go.mod: update golang.org/x dependencies

Update golang.org/x dependencies to their latest tagged versions.

Change-Id: I75e16a930bfe42cc082df82ab67802c42ad56a97
Reviewed-on: https://go-review.googlesource.com/c/crypto/+/701303
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Reviewed-by: Michael Pratt <mpratt@google.com>
Auto-Submit: Gopher Robot <gobot@golang.org>

README.md

@@ -2,20 +2,17 @@
 
 [![Go Reference](https://pkg.go.dev/badge/golang.org/x/crypto.svg)](https://pkg.go.dev/golang.org/x/crypto)
 
-This repository holds supplementary Go cryptography libraries.
-
-## Download/Install
-
-The easiest way to install is to run `go get -u golang.org/x/crypto/...`. You
-can also manually git clone the repository to `$GOPATH/src/golang.org/x/crypto`.
+This repository holds supplementary Go cryptography packages.
 
 ## Report Issues / Send Patches
 
 This repository uses Gerrit for code changes. To learn how to submit changes to
-this repository, see https://golang.org/doc/contribute.html.
+this repository, see https://go.dev/doc/contribute.
+
+The git repository is https://go.googlesource.com/crypto.
 
 The main issue tracker for the crypto repository is located at
-https://github.com/golang/go/issues. Prefix your issue with "x/crypto:" in the
+https://go.dev/issues. Prefix your issue with "x/crypto:" in the
 subject line, so it is easy to find.
 
 Note that contributions to the cryptography package receive additional scrutiny

acme/acme.go

@@ -31,12 +31,11 @@ import (
 	"crypto/x509/pkix"
 	"encoding/asn1"
 	"encoding/base64"
-	"encoding/hex"
 	"encoding/json"
-	"encoding/pem"
 	"errors"
 	"fmt"
 	"math/big"
+	"net"
 	"net/http"
 	"strings"
 	"sync"
@@ -353,6 +352,10 @@ func (c *Client) authorize(ctx context.Context, typ, val string) (*Authorization
 	if _, err := c.Discover(ctx); err != nil {
 		return nil, err
 	}
+	if c.dir.AuthzURL == "" {
+		// Pre-Authorization is unsupported
+		return nil, errPreAuthorizationNotSupported
+	}
 
 	type authzID struct {
 		Type  string `json:"type"`
@@ -467,7 +470,7 @@ func (c *Client) WaitAuthorization(ctx context.Context, url string) (*Authorizat
 		// while waiting for a final authorization status.
 		d := retryAfter(res.Header.Get("Retry-After"))
 		if d == 0 {
-			// Given that the fastest challenges TLS-SNI and HTTP-01
+			// Given that the fastest challenges TLS-ALPN and HTTP-01
 			// require a CA to make at least 1 network round trip
 			// and most likely persist a challenge state,
 			// this default delay seems reasonable.
@@ -514,7 +517,11 @@ func (c *Client) Accept(ctx context.Context, chal *Challenge) (*Challenge, error
 		return nil, err
 	}
 
-	res, err := c.post(ctx, nil, chal.URI, json.RawMessage("{}"), wantStatus(
+	payload := json.RawMessage("{}")
+	if len(chal.Payload) != 0 {
+		payload = chal.Payload
+	}
+	res, err := c.post(ctx, nil, chal.URI, payload, wantStatus(
 		http.StatusOK,       // according to the spec
 		http.StatusAccepted, // Let's Encrypt: see https://goo.gl/WsJ7VT (acme-divergences.md)
 	))
@@ -564,50 +571,28 @@ func (c *Client) HTTP01ChallengePath(token string) string {
 }
 
 // TLSSNI01ChallengeCert creates a certificate for TLS-SNI-01 challenge response.
+// Always returns an error.
 //
-// Deprecated: This challenge type is unused in both draft-02 and RFC versions of the ACME spec.
-func (c *Client) TLSSNI01ChallengeCert(token string, opt ...CertOption) (cert tls.Certificate, name string, err error) {
-	ka, err := keyAuth(c.Key.Public(), token)
-	if err != nil {
-		return tls.Certificate{}, "", err
-	}
-	b := sha256.Sum256([]byte(ka))
-	h := hex.EncodeToString(b[:])
-	name = fmt.Sprintf("%s.%s.acme.invalid", h[:32], h[32:])
-	cert, err = tlsChallengeCert([]string{name}, opt)
-	if err != nil {
-		return tls.Certificate{}, "", err
-	}
-	return cert, name, nil
+// Deprecated: This challenge type was only present in pre-standardized ACME
+// protocol drafts and is insecure for use in shared hosting environments.
+func (c *Client) TLSSNI01ChallengeCert(token string, opt ...CertOption) (tls.Certificate, string, error) {
+	return tls.Certificate{}, "", errPreRFC
 }
 
 // TLSSNI02ChallengeCert creates a certificate for TLS-SNI-02 challenge response.
+// Always returns an error.
 //
-// Deprecated: This challenge type is unused in both draft-02 and RFC versions of the ACME spec.
-func (c *Client) TLSSNI02ChallengeCert(token string, opt ...CertOption) (cert tls.Certificate, name string, err error) {
-	b := sha256.Sum256([]byte(token))
-	h := hex.EncodeToString(b[:])
-	sanA := fmt.Sprintf("%s.%s.token.acme.invalid", h[:32], h[32:])
-
-	ka, err := keyAuth(c.Key.Public(), token)
-	if err != nil {
-		return tls.Certificate{}, "", err
-	}
-	b = sha256.Sum256([]byte(ka))
-	h = hex.EncodeToString(b[:])
-	sanB := fmt.Sprintf("%s.%s.ka.acme.invalid", h[:32], h[32:])
-
-	cert, err = tlsChallengeCert([]string{sanA, sanB}, opt)
-	if err != nil {
-		return tls.Certificate{}, "", err
-	}
-	return cert, sanA, nil
+// Deprecated: This challenge type was only present in pre-standardized ACME
+// protocol drafts and is insecure for use in shared hosting environments.
+func (c *Client) TLSSNI02ChallengeCert(token string, opt ...CertOption) (tls.Certificate, string, error) {
+	return tls.Certificate{}, "", errPreRFC
 }
 
 // TLSALPN01ChallengeCert creates a certificate for TLS-ALPN-01 challenge response.
 // Servers can present the certificate to validate the challenge and prove control
-// over a domain name. For more details on TLS-ALPN-01 see
-// https://tools.ietf.org/html/draft-shoemaker-acme-tls-alpn-00#section-3
+// over an identifier (either a DNS name or the textual form of an IPv4 or IPv6
+// address). For more details on TLS-ALPN-01 see
+// https://www.rfc-editor.org/rfc/rfc8737 and https://www.rfc-editor.org/rfc/rfc8738
 //
 // The token argument is a Challenge.Token value.
 // If a WithKey option is provided, its private part signs the returned cert,
@@ -615,9 +600,13 @@ func (c *Client) TLSSNI02ChallengeCert(token string, opt ...CertOption) (cert tl
 // If no WithKey option is provided, a new ECDSA key is generated using P-256 curve.
 //
 // The returned certificate is valid for the next 24 hours and must be presented only when
-// the server name in the TLS ClientHello matches the domain, and the special acme-tls/1 ALPN protocol
+// the server name in the TLS ClientHello matches the identifier, and the special acme-tls/1 ALPN protocol
 // has been specified.
-func (c *Client) TLSALPN01ChallengeCert(token, domain string, opt ...CertOption) (cert tls.Certificate, err error) {
+//
+// Validation requests for IP address identifiers will use the reverse DNS form in the server name
+// in the TLS ClientHello since the SNI extension is not supported for IP addresses.
+// See RFC 8738 Section 6 for more information.
+func (c *Client) TLSALPN01ChallengeCert(token, identifier string, opt ...CertOption) (cert tls.Certificate, err error) {
 	ka, err := keyAuth(c.Key.Public(), token)
 	if err != nil {
 		return tls.Certificate{}, err
@@ -647,7 +636,7 @@ func (c *Client) TLSALPN01ChallengeCert(token, domain string, opt ...CertOption)
 	}
 	tmpl.ExtraExtensions = append(tmpl.ExtraExtensions, acmeExtension)
 	newOpt = append(newOpt, WithTemplate(tmpl))
-	return tlsChallengeCert([]string{domain}, newOpt)
+	return tlsChallengeCert(identifier, newOpt)
 }
 
 // popNonce returns a nonce value previously stored with c.addNonce
@@ -765,11 +754,15 @@ func defaultTLSChallengeCertTemplate() *x509.Certificate {
 	}
 }
 
-// tlsChallengeCert creates a temporary certificate for TLS-SNI challenges
-// with the given SANs and auto-generated public/private key pair.
-// The Subject Common Name is set to the first SAN to aid debugging.
+// tlsChallengeCert creates a temporary certificate for TLS-ALPN challenges
+// for the given identifier, using an auto-generated public/private key pair.
+//
+// If the provided identifier is a domain name, it will be used as a DNS type SAN and for the
+// subject common name. If the provided identifier is an IP address it will be used as an IP type
+// SAN.
+//
 // To create a cert with a custom key pair, specify WithKey option.
-func tlsChallengeCert(san []string, opt []CertOption) (tls.Certificate, error) {
+func tlsChallengeCert(identifier string, opt []CertOption) (tls.Certificate, error) {
 	var key crypto.Signer
 	tmpl := defaultTLSChallengeCertTemplate()
 	for _, o := range opt {
@@ -793,9 +786,12 @@ func tlsChallengeCert(san []string, opt []CertOption) (tls.Certificate, error) {
 			return tls.Certificate{}, err
 		}
 	}
-	tmpl.DNSNames = san
-	if len(san) > 0 {
-		tmpl.Subject.CommonName = san[0]
+
+	if ip := net.ParseIP(identifier); ip != nil {
+		tmpl.IPAddresses = []net.IP{ip}
+	} else {
+		tmpl.DNSNames = []string{identifier}
+		tmpl.Subject.CommonName = identifier
 	}
 
 	der, err := x509.CreateCertificate(rand.Reader, tmpl, tmpl, key.Public(), key)
@@ -808,11 +804,5 @@ func tlsChallengeCert(san []string, opt []CertOption) (tls.Certificate, error) {
 	}, nil
 }
 
-// encodePEM returns b encoded as PEM with block of type typ.
-func encodePEM(typ string, b []byte) []byte {
-	pb := &pem.Block{Type: typ, Bytes: b}
-	return pem.EncodeToMemory(pb)
-}
-
 // timeNow is time.Now, except in tests which can mess with it.
 var timeNow = time.Now

acme/acme_test.go

@@ -9,20 +9,18 @@ import (
 	"context"
 	"crypto/rand"
 	"crypto/rsa"
-	"crypto/tls"
 	"crypto/x509"
 	"crypto/x509/pkix"
 	"encoding/base64"
 	"encoding/hex"
 	"encoding/json"
+	"errors"
 	"fmt"
 	"io"
 	"math/big"
 	"net/http"
 	"net/http/httptest"
 	"reflect"
-	"sort"
-	"strings"
 	"testing"
 	"time"
 )
@@ -254,6 +252,57 @@ func TestAuthorizeValid(t *testing.T) {
 	}
 }
 
+func TestAuthorizeUnsupported(t *testing.T) {
+	const (
+		nonce       = "https://example.com/acme/new-nonce"
+		reg         = "https://example.com/acme/new-acct"
+		order       = "https://example.com/acme/new-order"
+		revoke      = "https://example.com/acme/revoke-cert"
+		keychange   = "https://example.com/acme/key-change"
+		metaTerms   = "https://example.com/acme/terms/2017-5-30"
+		metaWebsite = "https://www.example.com/"
+		metaCAA     = "example.com"
+	)
+	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Replay-Nonce", "nonce")
+		if r.Method == http.MethodHead {
+			return
+		}
+		switch r.URL.Path {
+		case "/": // Directory
+			w.Header().Set("Content-Type", "application/json")
+			fmt.Fprintf(w, `{
+                "newNonce": %q,
+                "newAccount": %q,
+                "newOrder": %q,
+                "revokeCert": %q,
+                "keyChange": %q,
+                "meta": {
+                    "termsOfService": %q,
+                    "website": %q,
+                    "caaIdentities": [%q],
+                    "externalAccountRequired": true
+                }
+            }`, nonce, reg, order, revoke, keychange, metaTerms, metaWebsite, metaCAA)
+			w.WriteHeader(http.StatusOK)
+		case "/acme/new-authz":
+			w.WriteHeader(http.StatusBadRequest)
+		}
+	}))
+	defer ts.Close()
+	client := &Client{Key: testKey, DirectoryURL: ts.URL}
+	dir, err := client.Discover(context.Background())
+	if err != nil {
+		t.Fatal(err)
+	}
+	if dir.AuthzURL != "" {
+		t.Fatalf("expected AuthzURL to be empty, got %q", dir.AuthzURL)
+	}
+	if _, err := client.Authorize(context.Background(), "example.com"); !errors.Is(err, errPreAuthorizationNotSupported) {
+		t.Errorf("expected err to indicate pre-authorization is unsupported, got %+v", err)
+	}
+}
+
 func TestWaitAuthorization(t *testing.T) {
 	t.Run("wait loop", func(t *testing.T) {
 		var count int
@@ -640,71 +689,6 @@ func TestLinkHeader(t *testing.T) {
 	}
 }
 
-func TestTLSSNI01ChallengeCert(t *testing.T) {
-	const (
-		token = "evaGxfADs6pSRb2LAv9IZf17Dt3juxGJ-PCt92wr-oA"
-		// echo -n <token.testKeyECThumbprint> | shasum -a 256
-		san = "dbbd5eefe7b4d06eb9d1d9f5acb4c7cd.a27d320e4b30332f0b6cb441734ad7b0.acme.invalid"
-	)
-
-	tlscert, name, err := newTestClient().TLSSNI01ChallengeCert(token)
-	if err != nil {
-		t.Fatal(err)
-	}
-
-	if n := len(tlscert.Certificate); n != 1 {
-		t.Fatalf("len(tlscert.Certificate) = %d; want 1", n)
-	}
-	cert, err := x509.ParseCertificate(tlscert.Certificate[0])
-	if err != nil {
-		t.Fatal(err)
-	}
-	if len(cert.DNSNames) != 1 || cert.DNSNames[0] != san {
-		t.Fatalf("cert.DNSNames = %v; want %q", cert.DNSNames, san)
-	}
-	if cert.DNSNames[0] != name {
-		t.Errorf("cert.DNSNames[0] != name: %q vs %q", cert.DNSNames[0], name)
-	}
-	if cn := cert.Subject.CommonName; cn != san {
-		t.Errorf("cert.Subject.CommonName = %q; want %q", cn, san)
-	}
-}
-
-func TestTLSSNI02ChallengeCert(t *testing.T) {
-	const (
-		token = "evaGxfADs6pSRb2LAv9IZf17Dt3juxGJ-PCt92wr-oA"
-		// echo -n evaGxfADs6pSRb2LAv9IZf17Dt3juxGJ-PCt92wr-oA | shasum -a 256
-		sanA = "7ea0aaa69214e71e02cebb18bb867736.09b730209baabf60e43d4999979ff139.token.acme.invalid"
-		// echo -n <token.testKeyECThumbprint> | shasum -a 256
-		sanB = "dbbd5eefe7b4d06eb9d1d9f5acb4c7cd.a27d320e4b30332f0b6cb441734ad7b0.ka.acme.invalid"
-	)
-
-	tlscert, name, err := newTestClient().TLSSNI02ChallengeCert(token)
-	if err != nil {
-		t.Fatal(err)
-	}
-
-	if n := len(tlscert.Certificate); n != 1 {
-		t.Fatalf("len(tlscert.Certificate) = %d; want 1", n)
-	}
-	cert, err := x509.ParseCertificate(tlscert.Certificate[0])
-	if err != nil {
-		t.Fatal(err)
-	}
-	names := []string{sanA, sanB}
-	if !reflect.DeepEqual(cert.DNSNames, names) {
-		t.Fatalf("cert.DNSNames = %v;\nwant %v", cert.DNSNames, names)
-	}
-	sort.Strings(cert.DNSNames)
-	i := sort.SearchStrings(cert.DNSNames, name)
-	if i >= len(cert.DNSNames) || cert.DNSNames[i] != name {
-		t.Errorf("%v doesn't have %q", cert.DNSNames, name)
-	}
-	if cn := cert.Subject.CommonName; cn != sanA {
-		t.Errorf("CommonName = %q; want %q", cn, sanA)
-	}
-}
-
 func TestTLSALPN01ChallengeCert(t *testing.T) {
 	const (
 		token   = "evaGxfADs6pSRb2LAv9IZf17Dt3juxGJ-PCt92wr-oA"
@@ -757,10 +741,11 @@ func TestTLSALPN01ChallengeCert(t *testing.T) {
 }
 
 func TestTLSChallengeCertOpt(t *testing.T) {
-	key, err := rsa.GenerateKey(rand.Reader, 512)
+	key, err := rsa.GenerateKey(rand.Reader, 1024)
 	if err != nil {
 		t.Fatal(err)
 	}
+	domain := "example.com"
 	tmpl := &x509.Certificate{
 		SerialNumber: big.NewInt(2),
 		Subject:      pkix.Name{Organization: []string{"Test"}},
@@ -769,52 +754,43 @@ func TestTLSChallengeCertOpt(t *testing.T) {
 	opts := []CertOption{WithKey(key), WithTemplate(tmpl)}
 
 	client := newTestClient()
-	cert1, _, err := client.TLSSNI01ChallengeCert("token", opts...)
-	if err != nil {
-		t.Fatal(err)
-	}
-	cert2, _, err := client.TLSSNI02ChallengeCert("token", opts...)
+	cert, err := client.TLSALPN01ChallengeCert("token", domain, opts...)
 	if err != nil {
 		t.Fatal(err)
 	}
 
-	for i, tlscert := range []tls.Certificate{cert1, cert2} {
-		// verify generated cert private key
-		tlskey, ok := tlscert.PrivateKey.(*rsa.PrivateKey)
-		if !ok {
-			t.Errorf("%d: tlscert.PrivateKey is %T; want *rsa.PrivateKey", i, tlscert.PrivateKey)
-			continue
-		}
-		if tlskey.D.Cmp(key.D) != 0 {
-			t.Errorf("%d: tlskey.D = %v; want %v", i, tlskey.D, key.D)
-		}
-		// verify generated cert public key
-		x509Cert, err := x509.ParseCertificate(tlscert.Certificate[0])
-		if err != nil {
-			t.Errorf("%d: %v", i, err)
-			continue
-		}
-		tlspub, ok := x509Cert.PublicKey.(*rsa.PublicKey)
-		if !ok {
-			t.Errorf("%d: x509Cert.PublicKey is %T; want *rsa.PublicKey", i, x509Cert.PublicKey)
-			continue
-		}
-		if tlspub.N.Cmp(key.N) != 0 {
-			t.Errorf("%d: tlspub.N = %v; want %v", i, tlspub.N, key.N)
-		}
-		// verify template option
-		sn := big.NewInt(2)
-		if x509Cert.SerialNumber.Cmp(sn) != 0 {
-			t.Errorf("%d: SerialNumber = %v; want %v", i, x509Cert.SerialNumber, sn)
-		}
-		org := []string{"Test"}
-		if !reflect.DeepEqual(x509Cert.Subject.Organization, org) {
-			t.Errorf("%d: Subject.Organization = %+v; want %+v", i, x509Cert.Subject.Organization, org)
-		}
-		for _, v := range x509Cert.DNSNames {
-			if !strings.HasSuffix(v, ".acme.invalid") {
-				t.Errorf("%d: invalid DNSNames element: %q", i, v)
-			}
+	// verify generated cert private key
+	tlskey, ok := cert.PrivateKey.(*rsa.PrivateKey)
+	if !ok {
+		t.Fatalf("tlscert.PrivateKey is %T; want *rsa.PrivateKey", cert.PrivateKey)
+	}
+	if tlskey.D.Cmp(key.D) != 0 {
+		t.Errorf("tlskey.D = %v; want %v", tlskey.D, key.D)
+	}
+	// verify generated cert public key
+	x509Cert, err := x509.ParseCertificate(cert.Certificate[0])
+	if err != nil {
+		t.Fatal(err)
+	}
+	tlspub, ok := x509Cert.PublicKey.(*rsa.PublicKey)
+	if !ok {
+		t.Fatalf("x509Cert.PublicKey is %T; want *rsa.PublicKey", x509Cert.PublicKey)
+	}
+	if tlspub.N.Cmp(key.N) != 0 {
+		t.Errorf("tlspub.N = %v; want %v", tlspub.N, key.N)
+	}
+	// verify template option
+	sn := big.NewInt(2)
+	if x509Cert.SerialNumber.Cmp(sn) != 0 {
+		t.Errorf("SerialNumber = %v; want %v", x509Cert.SerialNumber, sn)
+	}
+	org := []string{"Test"}
+	if !reflect.DeepEqual(x509Cert.Subject.Organization, org) {
+		t.Errorf("Subject.Organization = %+v; want %+v", x509Cert.Subject.Organization, org)
+	}
+	for _, v := range x509Cert.DNSNames {
+		if v != domain {
+			t.Errorf("invalid DNSNames element: %q", v)
 		}
 	}
 }

acme/autocert/autocert.go

@@ -292,6 +292,10 @@ func (m *Manager) GetCertificate(hello *tls.ClientHelloInfo) (*tls.Certificate,
 	}
 
 	// regular domain
+	if err := m.hostPolicy()(ctx, name); err != nil {
+		return nil, err
+	}
+
 	ck := certKey{
 		domain: strings.TrimSuffix(name, "."), // golang.org/issue/18114
 		isRSA:  !supportsECDSA(hello),
@@ -305,9 +309,6 @@ func (m *Manager) GetCertificate(hello *tls.ClientHelloInfo) (*tls.Certificate,
 	}
 
 	// first-time
-	if err := m.hostPolicy()(ctx, name); err != nil {
-		return nil, err
-	}
 	cert, err = m.createCert(ctx, ck)
 	if err != nil {
 		return nil, err

acme/autocert/autocert_test.go

@@ -619,7 +619,7 @@ func TestCache(t *testing.T) {
 		PrivateKey:  ecdsaKey,
 	}
 
-	rsaKey, err := rsa.GenerateKey(rand.Reader, 512)
+	rsaKey, err := rsa.GenerateKey(rand.Reader, 1024)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -694,7 +694,7 @@ func TestValidCert(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	key3, err := rsa.GenerateKey(rand.Reader, 512)
+	key3, err := rsa.GenerateKey(rand.Reader, 1024)
 	if err != nil {
 		t.Fatal(err)
 	}

acme/autocert/internal/acmetest/ca.go

@@ -308,7 +308,7 @@ func (ca *CAServer) handle(w http.ResponseWriter, r *http.Request) {
 		}
 
 		if err := decodePayload(&req, r.Body); err != nil {
-			ca.httpErrorf(w, http.StatusBadRequest, err.Error())
+			ca.httpErrorf(w, http.StatusBadRequest, "%v", err)
 			return
 		}
 
@@ -328,7 +328,7 @@ func (ca *CAServer) handle(w http.ResponseWriter, r *http.Request) {
 			Identifiers []struct{ Value string }
 		}
 		if err := decodePayload(&req, r.Body); err != nil {
-			ca.httpErrorf(w, http.StatusBadRequest, err.Error())
+			ca.httpErrorf(w, http.StatusBadRequest, "%v", err)
 			return
 		}
 		ca.mu.Lock()
@@ -352,7 +352,7 @@ func (ca *CAServer) handle(w http.ResponseWriter, r *http.Request) {
 		defer ca.mu.Unlock()
 		o, err := ca.storedOrder(strings.TrimPrefix(r.URL.Path, "/orders/"))
 		if err != nil {
-			ca.httpErrorf(w, http.StatusBadRequest, err.Error())
+			ca.httpErrorf(w, http.StatusBadRequest, "%v", err)
 			return
 		}
 		if err := json.NewEncoder(w).Encode(o); err != nil {
@@ -412,7 +412,7 @@ func (ca *CAServer) handle(w http.ResponseWriter, r *http.Request) {
 		orderID := strings.TrimPrefix(r.URL.Path, "/new-cert/")
 		o, err := ca.storedOrder(orderID)
 		if err != nil {
-			ca.httpErrorf(w, http.StatusBadRequest, err.Error())
+			ca.httpErrorf(w, http.StatusBadRequest, "%v", err)
 			return
 		}
 		if o.Status != acme.StatusReady {
@@ -427,7 +427,7 @@ func (ca *CAServer) handle(w http.ResponseWriter, r *http.Request) {
 		b, _ := base64.RawURLEncoding.DecodeString(req.CSR)
 		csr, err := x509.ParseCertificateRequest(b)
 		if err != nil {
-			ca.httpErrorf(w, http.StatusBadRequest, err.Error())
+			ca.httpErrorf(w, http.StatusBadRequest, "%v", err)
 			return
 		}
 		// Issue the certificate.
@@ -449,7 +449,7 @@ func (ca *CAServer) handle(w http.ResponseWriter, r *http.Request) {
 		defer ca.mu.Unlock()
 		o, err := ca.storedOrder(strings.TrimPrefix(r.URL.Path, "/issued-cert/"))
 		if err != nil {
-			ca.httpErrorf(w, http.StatusBadRequest, err.Error())
+			ca.httpErrorf(w, http.StatusBadRequest, "%v", err)
 			return
 		}
 		if o.Status != acme.StatusValid {
@@ -782,15 +782,3 @@ func decodePayload(v interface{}, r io.Reader) error {
 func challengeToken(domain, challType string, authzID int) string {
 	return fmt.Sprintf("token-%s-%s-%d", domain, challType, authzID)
 }
-
-func unique(a []string) []string {
-	seen := make(map[string]bool)
-	var res []string
-	for _, s := range a {
-		if s != "" && !seen[s] {
-			seen[s] = true
-			res = append(res, s)
-		}
-	}
-	return res
-}

acme/autocert/listener.go

@@ -10,7 +10,6 @@ import (
 	"net"
 	"os"
 	"path/filepath"
-	"runtime"
 	"time"
 )
 
@@ -124,32 +123,13 @@ func (ln *listener) Close() error {
 	return ln.tcpListener.Close()
 }
 
-func homeDir() string {
-	if runtime.GOOS == "windows" {
-		return os.Getenv("HOMEDRIVE") + os.Getenv("HOMEPATH")
-	}
-	if h := os.Getenv("HOME"); h != "" {
-		return h
-	}
-	return "/"
-}
-
 func cacheDir() string {
 	const base = "golang-autocert"
-	switch runtime.GOOS {
-	case "darwin":
-		return filepath.Join(homeDir(), "Library", "Caches", base)
-	case "windows":
-		for _, ev := range []string{"APPDATA", "CSIDL_APPDATA", "TEMP", "TMP"} {
-			if v := os.Getenv(ev); v != "" {
-				return filepath.Join(v, base)
-			}
-		}
-		// Worst case:
-		return filepath.Join(homeDir(), base)
+	cache, err := os.UserCacheDir()
+	if err != nil {
+		// Fall back to the root directory.
+		cache = "/.cache"
 	}
-	if xdg := os.Getenv("XDG_CACHE_HOME"); xdg != "" {
-		return filepath.Join(xdg, base)
-	}
-	return filepath.Join(homeDir(), ".cache", base)
+
+	return filepath.Join(cache, base)
 }

acme/http.go

@@ -66,7 +66,7 @@ func (c *Client) retryTimer() *retryTimer {
 // The n argument is always bounded between 1 and 30.
 // The returned value is always greater than 0.
 func defaultBackoff(n int, r *http.Request, res *http.Response) time.Duration {
-	const max = 10 * time.Second
+	const maxVal = 10 * time.Second
 	var jitter time.Duration
 	if x, err := rand.Int(rand.Reader, big.NewInt(1000)); err == nil {
 		// Set the minimum to 1ms to avoid a case where
@@ -86,10 +86,7 @@ func defaultBackoff(n int, r *http.Request, res *http.Response) time.Duration {
 		n = 30
 	}
 	d := time.Duration(1<<uint(n-1))*time.Second + jitter
-	if d > max {
-		return max
-	}
-	return d
+	return min(d, maxVal)
 }
 
 // retryAfter parses a Retry-After HTTP header value,

acme/jws.go

@@ -92,7 +92,7 @@ func jwsEncodeJSON(claimset interface{}, key crypto.Signer, kid KeyID, nonce, ur
 	if err != nil {
 		return nil, err
 	}
-	phead := base64.RawURLEncoding.EncodeToString([]byte(phJSON))
+	phead := base64.RawURLEncoding.EncodeToString(phJSON)
 	var payload string
 	if val, ok := claimset.(string); ok {
 		payload = val

acme/pebble_test.go

@@ -0,0 +1,809 @@
+// Copyright 2025 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package acme_test
+
+import (
+	"bytes"
+	"context"
+	"crypto/ecdsa"
+	"crypto/elliptic"
+	"crypto/rand"
+	"crypto/tls"
+	"crypto/x509"
+	"encoding/json"
+	"encoding/pem"
+	"errors"
+	"flag"
+	"fmt"
+	"io"
+	"log"
+	"net"
+	"net/http"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"runtime"
+	"strings"
+	"sync"
+	"sync/atomic"
+	"testing"
+	"time"
+
+	"golang.org/x/crypto/acme"
+)
+
+const (
+	// pebbleModVersion is the module version used for Pebble and Pebble's
+	// challenge test server. It is ignored if `-pebble-local-dir` is provided.
+	pebbleModVersion = "v2.7.0"
+	// startingPort is the first port number used for binding interface
+	// addresses. Each call to takeNextPort() will increment a port number
+	// starting at this value.
+	startingPort = 5555
+)
+
+var (
+	pebbleLocalDir = flag.String(
+		"pebble-local-dir",
+		"",
+		"Local Pebble to use, instead of fetching from source",
+	)
+	nextPort atomic.Uint32
+)
+
+func init() {
+	nextPort.Store(startingPort)
+}
+
+func TestWithPebble(t *testing.T) {
+	// We want to use process groups w/ syscall.Kill, and the acme package
+	// is very platform-agnostic, so skip on non-Linux.
+	if runtime.GOOS != "linux" {
+		t.Skip("skipping pebble tests on non-linux OS")
+	}
+
+	if testing.Short() {
+		t.Skip("skipping pebble tests in short mode")
+	}
+
+	tests := []struct {
+		name     string
+		challSrv func(*environment) (challengeServer, string)
+	}{
+		{
+			name: "TLSALPN01-Issuance",
+			challSrv: func(env *environment) (challengeServer, string) {
+				bindAddr := fmt.Sprintf(":%d", env.config.TLSPort)
+				return newChallTLSServer(bindAddr), bindAddr
+			},
+		},
+
+		{
+			name: "HTTP01-Issuance",
+			challSrv: func(env *environment) (challengeServer, string) {
+				bindAddr := fmt.Sprintf(":%d", env.config.HTTPPort)
+				return newChallHTTPServer(bindAddr), bindAddr
+			},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			t.Parallel()
+
+			env := startPebbleEnvironment(t, nil)
+			challSrv, challSrvAddr := tt.challSrv(&env)
+			challSrv.Run()
+
+			t.Cleanup(func() {
+				challSrv.Shutdown()
+			})
+
+			waitForServer(t, challSrvAddr)
+			testIssuance(t, &env, challSrv)
+		})
+	}
+}
+
+// challengeServer abstracts over the details of running a challenge response
+// server for some supported acme.Challenge type. Responses are provisioned
+// during the test issuance process to be presented to the ACME server's
+// validation authority.
+type challengeServer interface {
+	Run()
+	Shutdown() error
+	Supported(chal *acme.Challenge) bool
+	Provision(client *acme.Client, ident acme.AuthzID, chal *acme.Challenge) error
+}
+
+// challTLSServer is a simple challenge response server that listens for TLS
+// connections on a specific port and if they are TLS-ALPN-01 challenge
+// requests, completes the handshake using the configured challenge response
+// certificate for the SNI value provided.
+type challTLSServer struct {
+	*http.Server
+	// mu protects challCerts.
+	mu sync.RWMutex
+	// challCerts is a map from SNI domain name to challenge response certificate.
+	challCerts map[string]*tls.Certificate
+}
+
+// https://datatracker.ietf.org/doc/html/rfc8737#section-4
+const acmeTLSAlpnProtocol = "acme-tls/1"
+
+func newChallTLSServer(address string) *challTLSServer {
+	challServer := &challTLSServer{Server: &http.Server{
+		Addr:         address,
+		ReadTimeout:  5 * time.Second,
+		WriteTimeout: 5 * time.Second,
+	}, challCerts: make(map[string]*tls.Certificate)}
+
+	// Configure the server to support the TLS-ALPN-01 challenge protocol
+	// and to use a callback for selecting the handshake certificate.
+	challServer.Server.TLSConfig = &tls.Config{
+		NextProtos:     []string{acmeTLSAlpnProtocol},
+		GetCertificate: challServer.getCertificate,
+	}
+
+	return challServer
+}
+
+func (c *challTLSServer) Shutdown() error {
+	log.Printf("challTLSServer: shutting down")
+	ctx, cancel := context.WithTimeout(context.Background(), 10)
+	defer cancel()
+	return c.Server.Shutdown(ctx)
+}
+
+func (c *challTLSServer) Run() {
+	go func() {
+		// Note: certFile and keyFile are empty because our config uses a
+		// GetCertificate callback.
+		if err := c.Server.ListenAndServeTLS("", ""); err != nil {
+			if !errors.Is(err, http.ErrServerClosed) {
+				log.Printf("challTLSServer error: %v", err)
+			}
+		}
+	}()
+}
+
+func (c *challTLSServer) Supported(chal *acme.Challenge) bool {
+	return chal.Type == "tls-alpn-01"
+}
+
+func (c *challTLSServer) Provision(client *acme.Client, ident acme.AuthzID, chal *acme.Challenge) error {
+	respCert, err := client.TLSALPN01ChallengeCert(chal.Token, ident.Value)
+	if err != nil {
+		return fmt.Errorf("challTLSServer: failed to generate challlenge response cert for %s: %w",
+			ident.Value, err)
+	}
+
+	log.Printf("challTLSServer: setting challenge response certificate for %s", ident.Value)
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	c.challCerts[ident.Value] = &respCert
+
+	return nil
+}
+
+func (c *challTLSServer) getCertificate(clientHello *tls.ClientHelloInfo) (*tls.Certificate, error) {
+	// Verify the request looks like a TLS-ALPN-01 challenge request.
+	if len(clientHello.SupportedProtos) != 1 || clientHello.SupportedProtos[0] != acmeTLSAlpnProtocol {
+		return nil, fmt.Errorf(
+			"challTLSServer: non-TLS-ALPN-01 challenge request received with SupportedProtos: %s",
+			clientHello.SupportedProtos)
+	}
+
+	serverName := clientHello.ServerName
+
+	// TLS-ALPN-01 challenge requests for IP addresses are encoded in the SNI
+	// using the reverse-DNS notation. See RFC 8738 Section 6:
+	//   https://www.rfc-editor.org/rfc/rfc8738.html#section-6
+	if strings.HasSuffix(serverName, ".in-addr.arpa") {
+		serverName = strings.TrimSuffix(serverName, ".in-addr.arpa")
+		parts := strings.Split(serverName, ".")
+		for i, j := 0, len(parts)-1; i < j; i, j = i+1, j-1 {
+			parts[i], parts[j] = parts[j], parts[i]
+		}
+		serverName = strings.Join(parts, ".")
+	}
+
+	log.Printf("challTLSServer: selecting certificate for request from %s for %s",
+		clientHello.Conn.RemoteAddr(), serverName)
+
+	c.mu.RLock()
+	defer c.mu.RUnlock()
+	cert := c.challCerts[serverName]
+	if cert == nil {
+		return nil, fmt.Errorf("challTLSServer: no challenge response certificate configured for %s", serverName)
+	}
+
+	return cert, nil
+}
+
+// challHTTPServer is a simple challenge response server that listens for HTTP
+// connections on a specific port and if they are HTTP-01 challenge requests,
+// serves the challenge response key authorization.
+type challHTTPServer struct {
+	*http.Server
+	// mu protects challMap
+	mu sync.RWMutex
+	// challMap is a mapping from request path to response body.
+	challMap map[string]string
+}
+
+func newChallHTTPServer(address string) *challHTTPServer {
+	challServer := &challHTTPServer{
+		Server: &http.Server{
+			Addr:         address,
+			ReadTimeout:  5 * time.Second,
+			WriteTimeout: 5 * time.Second,
+		},
+		challMap: make(map[string]string),
+	}
+
+	challServer.Server.Handler = challServer
+
+	return challServer
+}
+
+func (c *challHTTPServer) Supported(chal *acme.Challenge) bool {
+	return chal.Type == "http-01"
+}
+
+func (c *challHTTPServer) Provision(client *acme.Client, ident acme.AuthzID, chall *acme.Challenge) error {
+	path := client.HTTP01ChallengePath(chall.Token)
+	body, err := client.HTTP01ChallengeResponse(chall.Token)
+	if err != nil {
+		return fmt.Errorf("failed to generate HTTP-01 challenge response for %v challenge %s token %s: %w",
+			ident, chall.URI, chall.Token, err)
+	}
+
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	log.Printf("challHTTPServer: setting challenge response for %s", path)
+	c.challMap[path] = body
+
+	return nil
+}
+
+func (c *challHTTPServer) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	log.Printf("challHTTPServer: handling %s to %s from %s", r.Method, r.URL.Path, r.RemoteAddr)
+	if r.Method != http.MethodGet {
+		http.Error(w, "method not allowed", http.StatusMethodNotAllowed)
+		return
+	}
+
+	c.mu.RLock()
+	defer c.mu.RUnlock()
+	response, exists := c.challMap[r.URL.Path]
+
+	if !exists {
+		http.NotFound(w, r)
+		return
+	}
+
+	w.Header().Set("Content-Type", "text/plain")
+	w.Write([]byte(response))
+}
+
+func (c *challHTTPServer) Shutdown() error {
+	log.Printf("challHTTPServer: shutting down")
+	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
+	defer cancel()
+	return c.Server.Shutdown(ctx)
+}
+
+func (c *challHTTPServer) Run() {
+	go func() {
+		if err := c.Server.ListenAndServe(); err != nil {
+			if !errors.Is(err, http.ErrServerClosed) {
+				log.Printf("challHTTPServer error: %v", err)
+			}
+		}
+	}()
+}
+
+func testIssuance(t *testing.T, env *environment, challSrv challengeServer) {
+	t.Helper()
+
+	// Bound the total issuance process by a timeout of 60 seconds.
+	ctx, cancel := context.WithTimeout(context.Background(), 60*time.Second)
+	defer cancel()
+
+	// Create a new ACME account.
+	client := env.client
+	acct, err := client.Register(ctx, &acme.Account{}, acme.AcceptTOS)
+	if err != nil {
+		t.Fatalf("failed to register account: %v", err)
+	}
+	if acct.Status != acme.StatusValid {
+		t.Fatalf("expected new account status to be valid, got %v", acct.Status)
+	}
+	log.Printf("registered account: %s", acct.URI)
+
+	// Create a new order for some example identifiers
+	identifiers := []acme.AuthzID{
+		{
+			Type:  "dns",
+			Value: "example.com",
+		},
+		{
+			Type:  "dns",
+			Value: "www.example.com",
+		},
+		{
+			Type:  "ip",
+			Value: "127.0.0.1",
+		},
+	}
+	order, err := client.AuthorizeOrder(ctx, identifiers)
+	if err != nil {
+		t.Fatalf("failed to create order for %v: %v", identifiers, err)
+	}
+	if order.Status != acme.StatusPending {
+		t.Fatalf("expected new order status to be pending, got %v", order.Status)
+	}
+	orderURL := order.URI
+	log.Printf("created order: %v", orderURL)
+
+	// For each pending authz provision a supported challenge type's response
+	// with the test challenge server, and tell the ACME server to verify it.
+	for _, authzURL := range order.AuthzURLs {
+		authz, err := client.GetAuthorization(ctx, authzURL)
+		if err != nil {
+			t.Fatalf("failed to get order %s authorization %s: %v",
+				orderURL, authzURL, err)
+		}
+
+		if authz.Status != acme.StatusPending {
+			continue
+		}
+
+		for _, challenge := range authz.Challenges {
+			if challenge.Status != acme.StatusPending || !challSrv.Supported(challenge) {
+				continue
+			}
+
+			if err := challSrv.Provision(client, authz.Identifier, challenge); err != nil {
+				t.Fatalf("failed to provision challenge %s: %v", challenge.URI, err)
+			}
+
+			_, err = client.Accept(ctx, challenge)
+			if err != nil {
+				t.Fatalf("failed to accept order %s challenge %s: %v",
+					orderURL, challenge.URI, err)
+			}
+		}
+	}
+
+	// Wait for the order to become ready for finalization.
+	order, err = client.WaitOrder(ctx, order.URI)
+	if err != nil {
+		var orderErr *acme.OrderError
+		if errors.Is(err, orderErr) {
+			t.Fatalf("failed to wait for order %s: %s: %s", orderURL, err, orderErr.Problem)
+		} else {
+			t.Fatalf("failed to wait for order %s: %s", orderURL, err)
+		}
+	}
+	if order.Status != acme.StatusReady {
+		t.Fatalf("expected order %s status to be ready, got %v",
+			orderURL, order.Status)
+	}
+
+	// Generate a certificate keypair and a CSR for the order identifiers.
+	certKey, err := ecdsa.GenerateKey(elliptic.P256(), rand.Reader)
+	if err != nil {
+		t.Fatalf("failed to generate certificate key: %v", err)
+	}
+	var dnsNames []string
+	var ipAddresses []net.IP
+	for _, ident := range identifiers {
+		switch ident.Type {
+		case "dns":
+			dnsNames = append(dnsNames, ident.Value)
+		case "ip":
+			ipAddresses = append(ipAddresses, net.ParseIP(ident.Value))
+		default:
+			t.Fatalf("unsupported identifier type: %s", ident.Type)
+		}
+	}
+	csrDer, err := x509.CreateCertificateRequest(rand.Reader, &x509.CertificateRequest{
+		DNSNames:    dnsNames,
+		IPAddresses: ipAddresses,
+	}, certKey)
+	if err != nil {
+		t.Fatalf("failed to create CSR: %v", err)
+	}
+
+	// Finalize the order by creating a certificate with our CSR.
+	chain, _, err := client.CreateOrderCert(ctx, order.FinalizeURL, csrDer, true)
+	if err != nil {
+		t.Fatalf("failed to finalize order %s with finalize URL %s: %v",
+			orderURL, order.FinalizeURL, err)
+	}
+
+	// Split the chain into the leaf and any intermediates.
+	leaf := chain[0]
+	intermediatesDER := chain[1:]
+	leafCert, err := x509.ParseCertificate(leaf)
+	if err != nil {
+		t.Fatalf("failed to parse order %s leaf certificate: %v", orderURL, err)
+	}
+	intermediates := x509.NewCertPool()
+	for i, intermediateDER := range intermediatesDER {
+		intermediate, err := x509.ParseCertificate(intermediateDER)
+		if err != nil {
+			t.Fatalf("failed to parse intermediate %d: %v", i, err)
+		}
+		intermediates.AddCert(intermediate)
+	}
+
+	// Verify there is a valid path from the leaf certificate to Pebble's
+	// issuing root using the provided intermediate certificates.
+	roots, err := env.RootCert()
+	if err != nil {
+		t.Fatalf("failed to get Pebble issuer root certs: %v", err)
+	}
+	paths, err := leafCert.Verify(x509.VerifyOptions{
+		Intermediates: intermediates,
+		Roots:         roots,
+	})
+	if err != nil {
+		t.Fatalf("failed to verify order %s leaf certificate: %v", orderURL, err)
+	}
+	log.Printf("verified %d path(s) from issued leaf certificate to Pebble root CA", len(paths))
+
+	// Also verify that the leaf cert is valid for each of the DNS names
+	// and IP addresses from our order's identifiers.
+	for _, name := range dnsNames {
+		if err := leafCert.VerifyHostname(name); err != nil {
+			t.Fatalf("failed to verify order %s leaf certificate for order DNS name %s: %v",
+				orderURL, name, err)
+		}
+	}
+	for _, ip := range ipAddresses {
+		if err := leafCert.VerifyHostname(ip.String()); err != nil {
+			t.Fatalf("failed to verify order %s leaf certificate for order IP address %s: %v",
+				orderURL, ip, err)
+		}
+	}
+}
+
+type environment struct {
+	config *environmentConfig
+	client *acme.Client
+}
+
+// RootCert returns the Pebble CA's primary issuing hierarchy root certificate.
+// This is generated randomly at each startup and can be used to verify
+// certificate chains issued by Pebble's ACME interface. Note that this
+// is separate from the static root certificate used by the Pebble ACME
+// HTTPS interface.
+func (e *environment) RootCert() (*x509.CertPool, error) {
+	// NOTE: in the future we may want to consider the alternative chains
+	// 		 returned as Link alternative headers.
+	rootURL := fmt.Sprintf("https://%s/roots/0", e.config.pebbleConfig.ManagementListenAddress)
+	resp, err := e.client.HTTPClient.Get(rootURL)
+	if err != nil || resp.StatusCode != http.StatusOK {
+		return nil, fmt.Errorf("failed to GET Pebble root CA from %s: %v", rootURL, err)
+	}
+
+	roots := x509.NewCertPool()
+	rootPEM, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return nil, fmt.Errorf("failed to parse Pebble root CA PEM: %v", err)
+	}
+	rootDERBlock, _ := pem.Decode(rootPEM)
+	rootCA, err := x509.ParseCertificate(rootDERBlock.Bytes)
+	if err != nil {
+		return nil, fmt.Errorf("failed to parse Pebble root CA DER: %v", err)
+	}
+	roots.AddCert(rootCA)
+
+	return roots, nil
+}
+
+// environmentConfig describes the Pebble configuration, and configuration
+// shared between pebble and pebble-challtestsrv.
+type environmentConfig struct {
+	pebbleConfig
+	dnsPort uint32
+}
+
+// defaultConfig returns an environmentConfig populated with default values.
+// The provided pebbleDir is used to specify certificate/private key paths
+// for the HTTPS ACME interface.
+func defaultConfig(pebbleDir string) environmentConfig {
+	return environmentConfig{
+		pebbleConfig: pebbleConfig{
+			ListenAddress:                  fmt.Sprintf("127.0.0.1:%d", takeNextPort()),
+			ManagementListenAddress:        fmt.Sprintf("127.0.0.1:%d", takeNextPort()),
+			HTTPPort:                       takeNextPort(),
+			TLSPort:                        takeNextPort(),
+			Certificate:                    fmt.Sprintf("%s/test/certs/localhost/cert.pem", pebbleDir),
+			PrivateKey:                     fmt.Sprintf("%s/test/certs/localhost/key.pem", pebbleDir),
+			OCSPResponderURL:               "",
+			ExternalAccountBindingRequired: false,
+			ExternalAccountMACKeys:         make(map[string]string),
+			DomainBlocklist:                []string{"blocked-domain.example"},
+			Profiles: map[string]struct {
+				Description    string
+				ValidityPeriod uint64
+			}{
+				"default": {
+					Description:    "default profile",
+					ValidityPeriod: 3600,
+				},
+			},
+			RetryAfter: struct {
+				Authz int
+				Order int
+			}{
+				3,
+				5,
+			},
+		},
+		dnsPort: takeNextPort(),
+	}
+}
+
+// pebbleConfig matches the JSON structure of the Pebble configuration file.
+type pebbleConfig struct {
+	ListenAddress                  string
+	ManagementListenAddress        string
+	HTTPPort                       uint32
+	TLSPort                        uint32
+	Certificate                    string
+	PrivateKey                     string
+	OCSPResponderURL               string
+	ExternalAccountBindingRequired bool
+	ExternalAccountMACKeys         map[string]string
+	DomainBlocklist                []string
+	Profiles                       map[string]struct {
+		Description    string
+		ValidityPeriod uint64
+	}
+	RetryAfter struct {
+		Authz int
+		Order int
+	}
+}
+
+func takeNextPort() uint32 {
+	return nextPort.Add(1) - 1
+}
+
+// startPebbleEnvironment is a test helper that spawns Pebble and Pebble
+// challenge test server processes based on the provided environmentConfig. The
+// processes will be torn down when the test ends.
+func startPebbleEnvironment(t *testing.T, config *environmentConfig) environment {
+	t.Helper()
+
+	var pebbleDir string
+	if *pebbleLocalDir != "" {
+		pebbleDir = *pebbleLocalDir
+	} else {
+		pebbleDir = fetchModule(t, "github.com/letsencrypt/pebble/v2", pebbleModVersion)
+	}
+
+	binDir := prepareBinaries(t, pebbleDir)
+
+	if config == nil {
+		cfg := defaultConfig(pebbleDir)
+		config = &cfg
+	}
+
+	marshalConfig := struct {
+		Pebble pebbleConfig
+	}{
+		Pebble: config.pebbleConfig,
+	}
+
+	configData, err := json.Marshal(marshalConfig)
+	if err != nil {
+		t.Fatalf("failed to marshal config: %v", err)
+	}
+
+	configFile, err := os.CreateTemp("", "pebble-config-*.json")
+	if err != nil {
+		t.Fatalf("failed to create temp config file: %v", err)
+	}
+	t.Cleanup(func() { os.Remove(configFile.Name()) })
+
+	if _, err := configFile.Write(configData); err != nil {
+		t.Fatalf("failed to write config file: %v", err)
+	}
+	configFile.Close()
+
+	log.Printf("pebble dir: %s", pebbleDir)
+	log.Printf("config file: %s", configFile.Name())
+
+	// Spawn the Pebble CA server. It answers ACME requests and performs
+	// outbound validations. We configure it to use a mock DNS server that
+	// always answers 127.0.0.1 for all A queries so that validation
+	// requests for any domain name will resolve to our local challenge
+	// server instances.
+	spawnServerProcess(t, binDir, "pebble", "-config", configFile.Name(),
+		"-dnsserver", fmt.Sprintf("127.0.0.1:%d", config.dnsPort),
+		"-strict")
+
+	// Spawn the Pebble challenge test server. We'll use it to mock DNS
+	// responses but disable all the other interfaces. We want to stand
+	// up our own challenge response servers for TLS-ALPN-01,
+	// etc.
+	// Note: we specify -defaultIPv6 "" so that no AAAA records are served.
+	// The LUCI CI runners have issues with IPv6 connectivity on localhost.
+	spawnServerProcess(t, binDir, "pebble-challtestsrv",
+		"-dns01", fmt.Sprintf(":%d", config.dnsPort),
+		"-defaultIPv6", "",
+		"-management", fmt.Sprintf(":%d", takeNextPort()),
+		"-doh", "",
+		"-http01", "",
+		"-tlsalpn01", "",
+		"-https01", "")
+
+	waitForServer(t, config.pebbleConfig.ListenAddress)
+	waitForServer(t, fmt.Sprintf("127.0.0.1:%d", config.dnsPort))
+
+	log.Printf("pebble environment ready")
+
+	// Construct a cert pool that contains the CA certificate used by the ACME
+	// interface's certificate chain. This is separate from the issuing
+	// hierarchy and is used for the ACME client to interact with the ACME
+	// interface without cert verification error.
+	caCertPath := filepath.Join(pebbleDir, "test/certs/pebble.minica.pem")
+	caCert, err := os.ReadFile(caCertPath)
+	if err != nil {
+		t.Fatalf("failed to read CA certificate %s: %v", caCertPath, err)
+	}
+	caCertPool := x509.NewCertPool()
+	if !caCertPool.AppendCertsFromPEM(caCert) {
+		t.Fatalf("failed to parse CA certificate %s", caCertPath)
+	}
+	httpClient := &http.Client{
+		Transport: &http.Transport{
+			TLSClientConfig: &tls.Config{
+				RootCAs: caCertPool,
+			},
+		},
+	}
+
+	// Create an ACME account keypair/client and verify it can discover
+	// the Pebble server's ACME directory without error.
+	key, err := ecdsa.GenerateKey(elliptic.P256(), rand.Reader)
+	if err != nil {
+		t.Fatalf("failed to generate account key: %v", err)
+	}
+	client := &acme.Client{
+		Key:          key,
+		HTTPClient:   httpClient,
+		DirectoryURL: fmt.Sprintf("https://%s/dir", config.ListenAddress),
+	}
+	_, err = client.Discover(context.TODO())
+	if err != nil {
+		t.Fatalf("failed to discover ACME directory: %v", err)
+	}
+
+	return environment{
+		config: config,
+		client: client,
+	}
+}
+
+func waitForServer(t *testing.T, addr string) {
+	t.Helper()
+
+	for i := 0; i < 20; i++ {
+		if conn, err := net.Dial("tcp", addr); err == nil {
+			conn.Close()
+			return
+		}
+		time.Sleep(time.Duration(i*100) * time.Millisecond)
+	}
+	t.Fatalf("failed to connect to %q after 20 tries", addr)
+}
+
+// fetchModule fetches the module at the given version and returns the directory
+// containing its source tree. It skips the test if fetching modules is not
+// possible in this environment.
+//
+// Copied from the stdlib cryptotest.FetchModule and adapted to not rely on the
+// stdlib internal testenv package.
+func fetchModule(t *testing.T, module, version string) string {
+	// If the default GOMODCACHE doesn't exist, use a temporary directory
+	// instead. (For example, run.bash sets GOPATH=/nonexist-gopath.)
+	out, err := exec.Command("go", "env", "GOMODCACHE").Output()
+	if err != nil {
+		t.Errorf("go env GOMODCACHE: %v\n%s", err, out)
+		if ee, ok := err.(*exec.ExitError); ok {
+			t.Logf("%s", ee.Stderr)
+		}
+		t.FailNow()
+	}
+	modcacheOk := false
+	if gomodcache := string(bytes.TrimSpace(out)); gomodcache != "" {
+		if _, err := os.Stat(gomodcache); err == nil {
+			modcacheOk = true
+		}
+	}
+	if !modcacheOk {
+		t.Setenv("GOMODCACHE", t.TempDir())
+		// Allow t.TempDir() to clean up subdirectories.
+		t.Setenv("GOFLAGS", os.Getenv("GOFLAGS")+" -modcacherw")
+	}
+
+	t.Logf("fetching %s@%s\n", module, version)
+
+	output, err := exec.Command("go", "mod", "download", "-json", module+"@"+version).CombinedOutput()
+	if err != nil {
+		t.Fatalf("failed to download %s@%s: %s\n%s\n", module, version, err, output)
+	}
+	var j struct {
+		Dir string
+	}
+	if err := json.Unmarshal(output, &j); err != nil {
+		t.Fatalf("failed to parse 'go mod download': %s\n%s\n", err, output)
+	}
+
+	return j.Dir
+}
+
+func prepareBinaries(t *testing.T, pebbleDir string) string {
+	t.Helper()
+
+	// We don't want to build in the module cache dir, which might not be
+	// writable or to pollute the user's clone with binaries if pebbleLocalDir
+	//is used.
+	binDir := t.TempDir()
+
+	build := func(cmd string) {
+		log.Printf("building %s", cmd)
+		buildCmd := exec.Command(
+			"go",
+			"build", "-o", filepath.Join(binDir, cmd), "-mod", "mod", "./cmd/"+cmd)
+		buildCmd.Dir = pebbleDir
+		output, err := buildCmd.CombinedOutput()
+		if err != nil {
+			t.Fatalf("failed to build %s: %s\n%s\n", cmd, err, output)
+		}
+	}
+
+	build("pebble")
+	build("pebble-challtestsrv")
+
+	return binDir
+}
+
+func spawnServerProcess(t *testing.T, dir string, cmd string, args ...string) {
+	t.Helper()
+
+	var stdout, stderr bytes.Buffer
+
+	cmdInstance := exec.Command("./"+cmd, args...)
+	cmdInstance.Dir = dir
+	cmdInstance.Stdout = &stdout
+	cmdInstance.Stderr = &stderr
+
+	if err := cmdInstance.Start(); err != nil {
+		t.Fatalf("failed to start %s: %v", cmd, err)
+	}
+
+	t.Cleanup(func() {
+		cmdInstance.Process.Kill()
+		cmdInstance.Wait()
+
+		if t.Failed() || testing.Verbose() {
+			t.Logf("=== %s output ===", cmd)
+			if stdout.Len() > 0 {
+				t.Logf("stdout:\n%s", strings.TrimSpace(stdout.String()))
+			}
+			if stderr.Len() > 0 {
+				t.Logf("stderr:\n%s", strings.TrimSpace(stderr.String()))
+			}
+		}
+	})
+}

acme/rfc8555.go

@@ -272,7 +272,7 @@ func (c *Client) WaitOrder(ctx context.Context, url string) (*Order, error) {
 		case err != nil:
 			// Skip and retry.
 		case o.Status == StatusInvalid:
-			return nil, &OrderError{OrderURL: o.URI, Status: o.Status}
+			return nil, &OrderError{OrderURL: o.URI, Status: o.Status, Problem: o.Error}
 		case o.Status == StatusReady || o.Status == StatusValid:
 			return o, nil
 		}
@@ -369,7 +369,7 @@ func (c *Client) CreateOrderCert(ctx context.Context, url string, csr []byte, bu
 	}
 	// The only acceptable status post finalize and WaitOrder is "valid".
 	if o.Status != StatusValid {
-		return nil, "", &OrderError{OrderURL: o.URI, Status: o.Status}
+		return nil, "", &OrderError{OrderURL: o.URI, Status: o.Status, Problem: o.Error}
 	}
 	crt, err := c.fetchCertRFC(ctx, o.CertURL, bundle)
 	return crt, o.CertURL, err

acme/rfc8555_test.go

@@ -885,11 +885,17 @@ func TestRFC_WaitOrderError(t *testing.T) {
 	s.handle("/orders/1", func(w http.ResponseWriter, r *http.Request) {
 		w.Header().Set("Location", s.url("/orders/1"))
 		w.WriteHeader(http.StatusOK)
-		s := StatusPending
 		if count > 0 {
-			s = StatusInvalid
+			// https://www.rfc-editor.org/rfc/rfc8555#section-7.3.3
+			errorData := `{
+				"type": "urn:ietf:params:acme:error:userActionRequired",
+				"detail": "Terms of service have changed",
+				"instance": "https://example.com/acme/agreement/?token=W8Ih3PswD-8"
+			}`
+			fmt.Fprintf(w, `{"status": %q, "error": %s}`, StatusInvalid, errorData)
+		} else {
+			fmt.Fprintf(w, `{"status": %q}`, StatusPending)
 		}
-		fmt.Fprintf(w, `{"status": %q}`, s)
 		count++
 	})
 	s.start()
@@ -910,6 +916,13 @@ func TestRFC_WaitOrderError(t *testing.T) {
 	if e.Status != StatusInvalid {
 		t.Errorf("e.Status = %q; want %q", e.Status, StatusInvalid)
 	}
+	if e.Problem == nil {
+		t.Errorf("e.Problem = nil")
+	}
+	expectedProbType := "urn:ietf:params:acme:error:userActionRequired"
+	if e.Problem.ProblemType != expectedProbType {
+		t.Errorf("e.Problem.ProblemType = %q; want %q", e.Problem.ProblemType, expectedProbType)
+	}
 }
 
 func TestRFC_CreateOrderCert(t *testing.T) {

acme/types.go

@@ -7,6 +7,7 @@ package acme
 import (
 	"crypto"
 	"crypto/x509"
+	"encoding/json"
 	"errors"
 	"fmt"
 	"net/http"
@@ -55,6 +56,10 @@ var (
 
 	// ErrNoAccount indicates that the Client's key has not been registered with the CA.
 	ErrNoAccount = errors.New("acme: account does not exist")
+
+	// errPreAuthorizationNotSupported indicates that the server does not
+	// support pre-authorization of identifiers.
+	errPreAuthorizationNotSupported = errors.New("acme: pre-authorization is not supported")
 )
 
 // A Subproblem describes an ACME subproblem as reported in an Error.
@@ -149,13 +154,16 @@ func (a *AuthorizationError) Error() string {
 
 // OrderError is returned from Client's order related methods.
 // It indicates the order is unusable and the clients should start over with
-// AuthorizeOrder.
+// AuthorizeOrder. A Problem description may be provided with details on
+// what caused the order to become unusable.
 //
 // The clients can still fetch the order object from CA using GetOrder
 // to inspect its state.
 type OrderError struct {
 	OrderURL string
 	Status   string
+	// Problem is the error that occurred while processing the order.
+	Problem *Error
 }
 
 func (oe *OrderError) Error() string {
@@ -288,7 +296,7 @@ type Directory struct {
 	// KeyChangeURL allows to perform account key rollover flow.
 	KeyChangeURL string
 
-	// Term is a URI identifying the current terms of service.
+	// Terms is a URI identifying the current terms of service.
 	Terms string
 
 	// Website is an HTTP or HTTPS URL locating a website
@@ -527,6 +535,16 @@ type Challenge struct {
 	// when this challenge was used.
 	// The type of a non-nil value is *Error.
 	Error error
+
+	// Payload is the JSON-formatted payload that the client sends
+	// to the server to indicate it is ready to respond to the challenge.
+	// When unset, it defaults to an empty JSON object: {}.
+	// For most challenges, the client must not set Payload,
+	// see https://tools.ietf.org/html/rfc8555#section-7.5.1.
+	// Payload is used only for newer challenges (such as "device-attest-01")
+	// where the client must send additional data for the server to validate
+	// the challenge.
+	Payload json.RawMessage
 }
 
 // wireChallenge is ACME JSON challenge representation.
@@ -604,7 +622,7 @@ func (*certOptKey) privateCertOpt() {}
 //
 // In TLS ChallengeCert methods, the template is also used as parent,
 // resulting in a self-signed certificate.
-// The DNSNames field of t is always overwritten for tls-sni challenge certs.
+// The DNSNames or IPAddresses fields of t are always overwritten for tls-alpn challenge certs.
 func WithTemplate(t *x509.Certificate) CertOption {
 	return (*certOptTemplate)(t)
 }

argon2/_asm/blamka_amd64.go

@@ -0,0 +1,287 @@
+// Copyright 2024 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package main
+
+import (
+	. "github.com/mmcloughlin/avo/build"
+	. "github.com/mmcloughlin/avo/operand"
+	. "github.com/mmcloughlin/avo/reg"
+	_ "golang.org/x/crypto/argon2"
+)
+
+//go:generate go run . -out ../blamka_amd64.s -pkg argon2
+
+func main() {
+	Package("golang.org/x/crypto/argon2")
+	ConstraintExpr("amd64,gc,!purego")
+
+	blamkaSSE4()
+	mixBlocksSSE2()
+	xorBlocksSSE2()
+	Generate()
+}
+
+func blamkaSSE4() {
+	Implement("blamkaSSE4")
+	Attributes(NOSPLIT)
+	AllocLocal(0)
+
+	Load(Param("b"), RAX)
+
+	c40 := c40_DATA()
+	c48 := c48_DATA()
+
+	MOVOU(c40, X10)
+	MOVOU(c48, X11)
+
+	BLAMKA_ROUND_0(AX, 0, X8, X9, X10, X11)
+	BLAMKA_ROUND_0(AX, 16, X8, X9, X10, X11)
+	BLAMKA_ROUND_0(AX, 32, X8, X9, X10, X11)
+	BLAMKA_ROUND_0(AX, 48, X8, X9, X10, X11)
+	BLAMKA_ROUND_0(AX, 64, X8, X9, X10, X11)
+	BLAMKA_ROUND_0(AX, 80, X8, X9, X10, X11)
+	BLAMKA_ROUND_0(AX, 96, X8, X9, X10, X11)
+	BLAMKA_ROUND_0(AX, 112, X8, X9, X10, X11)
+
+	BLAMKA_ROUND_1(AX, 0, X8, X9, X10, X11)
+	BLAMKA_ROUND_1(AX, 2, X8, X9, X10, X11)
+	BLAMKA_ROUND_1(AX, 4, X8, X9, X10, X11)
+	BLAMKA_ROUND_1(AX, 6, X8, X9, X10, X11)
+	BLAMKA_ROUND_1(AX, 8, X8, X9, X10, X11)
+	BLAMKA_ROUND_1(AX, 10, X8, X9, X10, X11)
+	BLAMKA_ROUND_1(AX, 12, X8, X9, X10, X11)
+	BLAMKA_ROUND_1(AX, 14, X8, X9, X10, X11)
+	RET()
+}
+
+func mixBlocksSSE2() {
+	Implement("mixBlocksSSE2")
+	Attributes(NOSPLIT)
+	AllocLocal(0)
+
+	Load(Param("out"), RDX)
+	Load(Param("a"), RAX)
+	Load(Param("b"), RBX)
+	Load(Param("c"), RCX)
+	MOVQ(U32(128), RDI)
+
+	Label("loop")
+	MOVOU(Mem{Base: AX}.Offset(0), X0)
+	MOVOU(Mem{Base: BX}.Offset(0), X1)
+	MOVOU(Mem{Base: CX}.Offset(0), X2)
+	PXOR(X1, X0)
+	PXOR(X2, X0)
+	MOVOU(X0, Mem{Base: DX}.Offset(0))
+	ADDQ(Imm(16), RAX)
+	ADDQ(Imm(16), RBX)
+	ADDQ(Imm(16), RCX)
+	ADDQ(Imm(16), RDX)
+	SUBQ(Imm(2), RDI)
+	JA(LabelRef("loop"))
+	RET()
+}
+
+func xorBlocksSSE2() {
+	Implement("xorBlocksSSE2")
+	Attributes(NOSPLIT)
+	AllocLocal(0)
+
+	Load(Param("out"), RDX)
+	Load(Param("a"), RAX)
+	Load(Param("b"), RBX)
+	Load(Param("c"), RCX)
+	MOVQ(U32(128), RDI)
+
+	Label("loop")
+	MOVOU(Mem{Base: AX}.Offset(0), X0)
+	MOVOU(Mem{Base: BX}.Offset(0), X1)
+	MOVOU(Mem{Base: CX}.Offset(0), X2)
+	MOVOU(Mem{Base: DX}.Offset(0), X3)
+	PXOR(X1, X0)
+	PXOR(X2, X0)
+	PXOR(X3, X0)
+	MOVOU(X0, Mem{Base: DX}.Offset(0))
+	ADDQ(Imm(16), RAX)
+	ADDQ(Imm(16), RBX)
+	ADDQ(Imm(16), RCX)
+	ADDQ(Imm(16), RDX)
+	SUBQ(Imm(2), RDI)
+	JA(LabelRef("loop"))
+	RET()
+}
+
+func SHUFFLE(v2, v3, v4, v5, v6, v7, t1, t2 VecPhysical) {
+	MOVO(v4, t1)
+	MOVO(v5, v4)
+	MOVO(t1, v5)
+	MOVO(v6, t1)
+	PUNPCKLQDQ(v6, t2)
+	PUNPCKHQDQ(v7, v6)
+	PUNPCKHQDQ(t2, v6)
+	PUNPCKLQDQ(v7, t2)
+	MOVO(t1, v7)
+	MOVO(v2, t1)
+	PUNPCKHQDQ(t2, v7)
+	PUNPCKLQDQ(v3, t2)
+	PUNPCKHQDQ(t2, v2)
+	PUNPCKLQDQ(t1, t2)
+	PUNPCKHQDQ(t2, v3)
+}
+
+func SHUFFLE_INV(v2, v3, v4, v5, v6, v7, t1, t2 VecPhysical) {
+	MOVO(v4, t1)
+	MOVO(v5, v4)
+	MOVO(t1, v5)
+	MOVO(v2, t1)
+	PUNPCKLQDQ(v2, t2)
+	PUNPCKHQDQ(v3, v2)
+	PUNPCKHQDQ(t2, v2)
+	PUNPCKLQDQ(v3, t2)
+	MOVO(t1, v3)
+	MOVO(v6, t1)
+	PUNPCKHQDQ(t2, v3)
+	PUNPCKLQDQ(v7, t2)
+	PUNPCKHQDQ(t2, v6)
+	PUNPCKLQDQ(t1, t2)
+	PUNPCKHQDQ(t2, v7)
+}
+
+func HALF_ROUND(v0, v1, v2, v3, v4, v5, v6, v7, t0, c40, c48 VecPhysical) {
+	MOVO(v0, t0)
+	PMULULQ(v2, t0)
+	PADDQ(v2, v0)
+	PADDQ(t0, v0)
+	PADDQ(t0, v0)
+	PXOR(v0, v6)
+	PSHUFD(Imm(0xB1), v6, v6)
+	MOVO(v4, t0)
+	PMULULQ(v6, t0)
+	PADDQ(v6, v4)
+	PADDQ(t0, v4)
+	PADDQ(t0, v4)
+	PXOR(v4, v2)
+	PSHUFB(c40, v2)
+	MOVO(v0, t0)
+	PMULULQ(v2, t0)
+	PADDQ(v2, v0)
+	PADDQ(t0, v0)
+	PADDQ(t0, v0)
+	PXOR(v0, v6)
+	PSHUFB(c48, v6)
+	MOVO(v4, t0)
+	PMULULQ(v6, t0)
+	PADDQ(v6, v4)
+	PADDQ(t0, v4)
+	PADDQ(t0, v4)
+	PXOR(v4, v2)
+	MOVO(v2, t0)
+	PADDQ(v2, t0)
+	PSRLQ(Imm(63), v2)
+	PXOR(t0, v2)
+	MOVO(v1, t0)
+	PMULULQ(v3, t0)
+	PADDQ(v3, v1)
+	PADDQ(t0, v1)
+	PADDQ(t0, v1)
+	PXOR(v1, v7)
+	PSHUFD(Imm(0xB1), v7, v7)
+	MOVO(v5, t0)
+	PMULULQ(v7, t0)
+	PADDQ(v7, v5)
+	PADDQ(t0, v5)
+	PADDQ(t0, v5)
+	PXOR(v5, v3)
+	PSHUFB(c40, v3)
+	MOVO(v1, t0)
+	PMULULQ(v3, t0)
+	PADDQ(v3, v1)
+	PADDQ(t0, v1)
+	PADDQ(t0, v1)
+	PXOR(v1, v7)
+	PSHUFB(c48, v7)
+	MOVO(v5, t0)
+	PMULULQ(v7, t0)
+	PADDQ(v7, v5)
+	PADDQ(t0, v5)
+	PADDQ(t0, v5)
+	PXOR(v5, v3)
+	MOVO(v3, t0)
+	PADDQ(v3, t0)
+	PSRLQ(Imm(63), v3)
+	PXOR(t0, v3)
+}
+
+func LOAD_MSG_0(block GPPhysical, off int) {
+	var registers = []VecPhysical{X0, X1, X2, X3, X4, X5, X6, X7}
+	for i, r := range registers {
+		MOVOU(Mem{Base: block}.Offset(8*(off+(i*2))), r)
+	}
+}
+
+func STORE_MSG_0(block GPPhysical, off int) {
+	var registers = []VecPhysical{X0, X1, X2, X3, X4, X5, X6, X7}
+	for i, r := range registers {
+		MOVOU(r, Mem{Base: block}.Offset(8*(off+(i*2))))
+	}
+}
+
+func LOAD_MSG_1(block GPPhysical, off int) {
+	var registers = []VecPhysical{X0, X1, X2, X3, X4, X5, X6, X7}
+	for i, r := range registers {
+		MOVOU(Mem{Base: block}.Offset(8*off+i*16*8), r)
+	}
+}
+
+func STORE_MSG_1(block GPPhysical, off int) {
+	var registers = []VecPhysical{X0, X1, X2, X3, X4, X5, X6, X7}
+	for i, r := range registers {
+		MOVOU(r, Mem{Base: block}.Offset(8*off+i*16*8))
+	}
+}
+
+func BLAMKA_ROUND_0(block GPPhysical, off int, t0, t1, c40, c48 VecPhysical) {
+	LOAD_MSG_0(block, off)
+	HALF_ROUND(X0, X1, X2, X3, X4, X5, X6, X7, t0, c40, c48)
+	SHUFFLE(X2, X3, X4, X5, X6, X7, t0, t1)
+	HALF_ROUND(X0, X1, X2, X3, X4, X5, X6, X7, t0, c40, c48)
+	SHUFFLE_INV(X2, X3, X4, X5, X6, X7, t0, t1)
+	STORE_MSG_0(block, off)
+}
+
+func BLAMKA_ROUND_1(block GPPhysical, off int, t0, t1, c40, c48 VecPhysical) {
+	LOAD_MSG_1(block, off)
+	HALF_ROUND(X0, X1, X2, X3, X4, X5, X6, X7, t0, c40, c48)
+	SHUFFLE(X2, X3, X4, X5, X6, X7, t0, t1)
+	HALF_ROUND(X0, X1, X2, X3, X4, X5, X6, X7, t0, c40, c48)
+	SHUFFLE_INV(X2, X3, X4, X5, X6, X7, t0, t1)
+	STORE_MSG_1(block, off)
+}
+
+// ##------------------DATA SECTION-------------------##
+
+var c40_DATA_ptr, c48_DATA_ptr *Mem
+
+func c40_DATA() Mem {
+	if c40_DATA_ptr != nil {
+		return *c40_DATA_ptr
+	}
+
+	c40_DATA := GLOBL("·c40", NOPTR|RODATA)
+	c40_DATA_ptr = &c40_DATA
+	DATA(0x00, U64(0x0201000706050403))
+	DATA(0x08, U64(0x0a09080f0e0d0c0b))
+	return c40_DATA
+}
+func c48_DATA() Mem {
+	if c48_DATA_ptr != nil {
+		return *c48_DATA_ptr
+	}
+
+	c48_DATA := GLOBL("·c48", NOPTR|RODATA)
+	c48_DATA_ptr = &c48_DATA
+	DATA(0x00, U64(0x0100070605040302))
+	DATA(0x08, U64(0x09080f0e0d0c0b0a))
+	return c48_DATA
+}

argon2/_asm/go.mod

@@ -0,0 +1,15 @@
+module argon2/_asm
+
+go 1.23
+
+require (
+	github.com/mmcloughlin/avo v0.6.0
+	golang.org/x/crypto v0.33.0
+)
+
+require (
+	golang.org/x/mod v0.20.0 // indirect
+	golang.org/x/sync v0.8.0 // indirect
+	golang.org/x/sys v0.30.0 // indirect
+	golang.org/x/tools v0.24.0 // indirect
+)

argon2/_asm/go.sum

@@ -0,0 +1,12 @@
+github.com/mmcloughlin/avo v0.6.0 h1:QH6FU8SKoTLaVs80GA8TJuLNkUYl4VokHKlPhVDg4YY=
+github.com/mmcloughlin/avo v0.6.0/go.mod h1:8CoAGaCSYXtCPR+8y18Y9aB/kxb8JSS6FRI7mSkvD+8=
+golang.org/x/crypto v0.33.0 h1:IOBPskki6Lysi0lo9qQvbxiQ+FvsCC/YWOecCHAixus=
+golang.org/x/crypto v0.33.0/go.mod h1:bVdXmD7IV/4GdElGPozy6U7lWdRXA4qyRVGJV57uQ5M=
+golang.org/x/mod v0.20.0 h1:utOm6MM3R3dnawAiJgn0y+xvuYRsm1RKM/4giyfDgV0=
+golang.org/x/mod v0.20.0/go.mod h1:hTbmBsO62+eylJbnUtE2MGJUyE7QWk4xUqPFrRgJ+7c=
+golang.org/x/sync v0.8.0 h1:3NFvSEYkUoMifnESzZl15y791HH1qU2xm6eCJU5ZPXQ=
+golang.org/x/sync v0.8.0/go.mod h1:Czt+wKu1gCyEFDUtn0jG5QVvpJ6rzVqr5aXyt9drQfk=
+golang.org/x/sys v0.30.0 h1:QjkSwP/36a20jFYWkSue1YwXzLmsV5Gfq7Eiy72C1uc=
+golang.org/x/sys v0.30.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
+golang.org/x/tools v0.24.0 h1:J1shsA93PJUEVaUSaay7UXAyE8aimq3GW0pjlolpa24=
+golang.org/x/tools v0.24.0/go.mod h1:YhNqVBIfWHdzvTLs0d8LCuMhkKUgSUKldakyV7W/WDQ=

bcrypt/bcrypt.go

@@ -50,7 +50,7 @@ func (ih InvalidHashPrefixError) Error() string {
 type InvalidCostError int
 
 func (ic InvalidCostError) Error() string {
-	return fmt.Sprintf("crypto/bcrypt: cost %d is outside allowed range (%d,%d)", int(ic), MinCost, MaxCost)
+	return fmt.Sprintf("crypto/bcrypt: cost %d is outside allowed inclusive range %d..%d", int(ic), MinCost, MaxCost)
 }
 
 const (

blake2b/_asm/AVX2/go.mod

@@ -0,0 +1,16 @@
+module blake2b/_asm/AVX2
+
+go 1.23
+
+require (
+	github.com/mmcloughlin/avo v0.6.0
+	golang.org/x/crypto v0.33.0
+
+)
+
+require (
+	golang.org/x/mod v0.20.0 // indirect
+	golang.org/x/sync v0.8.0 // indirect
+	golang.org/x/sys v0.30.0 // indirect
+	golang.org/x/tools v0.24.0 // indirect
+)

blake2b/_asm/AVX2/go.sum

@@ -0,0 +1,12 @@
+github.com/mmcloughlin/avo v0.6.0 h1:QH6FU8SKoTLaVs80GA8TJuLNkUYl4VokHKlPhVDg4YY=
+github.com/mmcloughlin/avo v0.6.0/go.mod h1:8CoAGaCSYXtCPR+8y18Y9aB/kxb8JSS6FRI7mSkvD+8=
+golang.org/x/crypto v0.33.0 h1:IOBPskki6Lysi0lo9qQvbxiQ+FvsCC/YWOecCHAixus=
+golang.org/x/crypto v0.33.0/go.mod h1:bVdXmD7IV/4GdElGPozy6U7lWdRXA4qyRVGJV57uQ5M=
+golang.org/x/mod v0.20.0 h1:utOm6MM3R3dnawAiJgn0y+xvuYRsm1RKM/4giyfDgV0=
+golang.org/x/mod v0.20.0/go.mod h1:hTbmBsO62+eylJbnUtE2MGJUyE7QWk4xUqPFrRgJ+7c=
+golang.org/x/sync v0.8.0 h1:3NFvSEYkUoMifnESzZl15y791HH1qU2xm6eCJU5ZPXQ=
+golang.org/x/sync v0.8.0/go.mod h1:Czt+wKu1gCyEFDUtn0jG5QVvpJ6rzVqr5aXyt9drQfk=
+golang.org/x/sys v0.30.0 h1:QjkSwP/36a20jFYWkSue1YwXzLmsV5Gfq7Eiy72C1uc=
+golang.org/x/sys v0.30.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
+golang.org/x/tools v0.24.0 h1:J1shsA93PJUEVaUSaay7UXAyE8aimq3GW0pjlolpa24=
+golang.org/x/tools v0.24.0/go.mod h1:YhNqVBIfWHdzvTLs0d8LCuMhkKUgSUKldakyV7W/WDQ=

blake2b/_asm/standard/blake2b_amd64_asm.go

@@ -0,0 +1,361 @@
+// Copyright 2024 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package main
+
+import (
+	. "github.com/mmcloughlin/avo/build"
+	. "github.com/mmcloughlin/avo/operand"
+	. "github.com/mmcloughlin/avo/reg"
+	_ "golang.org/x/crypto/blake2b"
+)
+
+//go:generate go run . -out ../../blake2b_amd64.s -pkg blake2b
+
+const ThatPeskyUnicodeDot = "\u00b7"
+
+var iv0_DATA_ptr, iv1_DATA_ptr, iv2_DATA_ptr, iv3_DATA_ptr, c40_DATA_ptr, c48_DATA_ptr *Mem
+
+func main() {
+	Package("golang.org/x/crypto/blake2b")
+	ConstraintExpr("amd64,gc,!purego")
+	hashBlocksSSE4()
+	Generate()
+}
+
+func SHUFFLE(v2, v3, v4, v5, v6, v7, t1, t2 VecPhysical) {
+	MOVO(v4, t1)
+	MOVO(v5, v4)
+	MOVO(t1, v5)
+	MOVO(v6, t1)
+	PUNPCKLQDQ(v6, t2)
+	PUNPCKHQDQ(v7, v6)
+	PUNPCKHQDQ(t2, v6)
+	PUNPCKLQDQ(v7, t2)
+	MOVO(t1, v7)
+	MOVO(v2, t1)
+	PUNPCKHQDQ(t2, v7)
+	PUNPCKLQDQ(v3, t2)
+	PUNPCKHQDQ(t2, v2)
+	PUNPCKLQDQ(t1, t2)
+	PUNPCKHQDQ(t2, v3)
+}
+
+func SHUFFLE_INV(v2, v3, v4, v5, v6, v7, t1, t2 VecPhysical) {
+	MOVO(v4, t1)
+	MOVO(v5, v4)
+	MOVO(t1, v5)
+	MOVO(v2, t1)
+	PUNPCKLQDQ(v2, t2)
+	PUNPCKHQDQ(v3, v2)
+	PUNPCKHQDQ(t2, v2)
+	PUNPCKLQDQ(v3, t2)
+	MOVO(t1, v3)
+	MOVO(v6, t1)
+	PUNPCKHQDQ(t2, v3)
+	PUNPCKLQDQ(v7, t2)
+	PUNPCKHQDQ(t2, v6)
+	PUNPCKLQDQ(t1, t2)
+	PUNPCKHQDQ(t2, v7)
+}
+
+func HALF_ROUND(v0, v1, v2, v3, v4, v5, v6, v7 VecPhysical, m0, m1, m2, m3 Op, t0, c40, c48 VecPhysical) {
+	PADDQ(m0, v0)
+	PADDQ(m1, v1)
+	PADDQ(v2, v0)
+	PADDQ(v3, v1)
+	PXOR(v0, v6)
+	PXOR(v1, v7)
+	PSHUFD(Imm(0xB1), v6, v6)
+	PSHUFD(Imm(0xB1), v7, v7)
+	PADDQ(v6, v4)
+	PADDQ(v7, v5)
+	PXOR(v4, v2)
+	PXOR(v5, v3)
+	PSHUFB(c40, v2)
+	PSHUFB(c40, v3)
+	PADDQ(m2, v0)
+	PADDQ(m3, v1)
+	PADDQ(v2, v0)
+	PADDQ(v3, v1)
+	PXOR(v0, v6)
+	PXOR(v1, v7)
+	PSHUFB(c48, v6)
+	PSHUFB(c48, v7)
+	PADDQ(v6, v4)
+	PADDQ(v7, v5)
+	PXOR(v4, v2)
+	PXOR(v5, v3)
+	MOVOU(v2, t0)
+	PADDQ(v2, t0)
+	PSRLQ(Imm(63), v2)
+	PXOR(t0, v2)
+	MOVOU(v3, t0)
+	PADDQ(v3, t0)
+	PSRLQ(Imm(63), v3)
+	PXOR(t0, v3)
+}
+
+func LOAD_MSG(m0, m1, m2, m3 VecPhysical, src GPPhysical, i0, i1, i2, i3, i4, i5, i6, i7 int) {
+	MOVQ(Mem{Base: src}.Offset(i0*8), m0)
+	PINSRQ(Imm(1), Mem{Base: src}.Offset(i1*8), m0)
+	MOVQ(Mem{Base: src}.Offset(i2*8), m1)
+	PINSRQ(Imm(1), Mem{Base: src}.Offset(i3*8), m1)
+	MOVQ(Mem{Base: src}.Offset(i4*8), m2)
+	PINSRQ(Imm(1), Mem{Base: src}.Offset(i5*8), m2)
+	MOVQ(Mem{Base: src}.Offset(i6*8), m3)
+	PINSRQ(Imm(1), Mem{Base: src}.Offset(i7*8), m3)
+}
+
+func hashBlocksSSE4() {
+	Implement("hashBlocksSSE4")
+	Attributes(4)
+	AllocLocal(288) // frame size = 272 + 16 byte alignment
+
+	Load(Param("h"), RAX)
+	Load(Param("c"), RBX)
+	Load(Param("flag"), RCX)
+	Load(Param("blocks").Base(), RSI)
+	Load(Param("blocks").Len(), RDI)
+
+	MOVQ(RSP, R10)
+	ADDQ(Imm(15), R10)
+	ANDQ(I32(-16), R10)
+
+	iv3 := iv3_DATA()
+	MOVOU(iv3, X0)
+	MOVO(X0, Mem{Base: R10}.Offset(0))
+	XORQ(RCX, Mem{Base: R10}.Offset(0)) // 0(R10) = ·iv3 ^ (CX || 0)
+
+	c40 := c40_DATA()
+	c48 := c48_DATA()
+	MOVOU(c40, X13)
+	MOVOU(c48, X14)
+
+	MOVOU(Mem{Base: AX}.Offset(0), X12)
+	MOVOU(Mem{Base: AX}.Offset(16), X15)
+
+	MOVQ(Mem{Base: BX}.Offset(0), R8)
+	MOVQ(Mem{Base: BX}.Offset(8), R9)
+
+	Label("loop")
+	ADDQ(Imm(128), R8)
+	CMPQ(R8, Imm(128))
+	JGE(LabelRef("noinc"))
+	INCQ(R9)
+
+	Label("noinc")
+	MOVQ(R8, X8)
+	PINSRQ(Imm(1), R9, X8)
+
+	iv0 := iv0_DATA()
+	iv1 := iv1_DATA()
+	iv2 := iv2_DATA()
+
+	MOVO(X12, X0)
+	MOVO(X15, X1)
+	MOVOU(Mem{Base: AX}.Offset(32), X2)
+	MOVOU(Mem{Base: AX}.Offset(48), X3)
+	MOVOU(iv0, X4)
+	MOVOU(iv1, X5)
+	MOVOU(iv2, X6)
+
+	PXOR(X8, X6)
+	MOVO(Mem{Base: R10}.Offset(0), X7)
+
+	LOAD_MSG(X8, X9, X10, X11, SI, 0, 2, 4, 6, 1, 3, 5, 7)
+	MOVO(X8, Mem{Base: R10}.Offset(16))
+	MOVO(X9, Mem{Base: R10}.Offset(32))
+	MOVO(X10, Mem{Base: R10}.Offset(48))
+	MOVO(X11, Mem{Base: R10}.Offset(64))
+	HALF_ROUND(X0, X1, X2, X3, X4, X5, X6, X7, X8, X9, X10, X11, X11, X13, X14)
+	SHUFFLE(X2, X3, X4, X5, X6, X7, X8, X9)
+	LOAD_MSG(X8, X9, X10, X11, SI, 8, 10, 12, 14, 9, 11, 13, 15)
+	MOVO(X8, Mem{Base: R10}.Offset(80))
+	MOVO(X9, Mem{Base: R10}.Offset(96))
+	MOVO(X10, Mem{Base: R10}.Offset(112))
+	MOVO(X11, Mem{Base: R10}.Offset(128))
+	HALF_ROUND(X0, X1, X2, X3, X4, X5, X6, X7, X8, X9, X10, X11, X11, X13, X14)
+	SHUFFLE_INV(X2, X3, X4, X5, X6, X7, X8, X9)
+
+	LOAD_MSG(X8, X9, X10, X11, SI, 14, 4, 9, 13, 10, 8, 15, 6)
+	MOVO(X8, Mem{Base: R10}.Offset(144))
+	MOVO(X9, Mem{Base: R10}.Offset(160))
+	MOVO(X10, Mem{Base: R10}.Offset(176))
+	MOVO(X11, Mem{Base: R10}.Offset(192))
+	HALF_ROUND(X0, X1, X2, X3, X4, X5, X6, X7, X8, X9, X10, X11, X11, X13, X14)
+	SHUFFLE(X2, X3, X4, X5, X6, X7, X8, X9)
+	LOAD_MSG(X8, X9, X10, X11, SI, 1, 0, 11, 5, 12, 2, 7, 3)
+	MOVO(X8, Mem{Base: R10}.Offset(208))
+	MOVO(X9, Mem{Base: R10}.Offset(224))
+	MOVO(X10, Mem{Base: R10}.Offset(240))
+	MOVO(X11, Mem{Base: R10}.Offset(256))
+	HALF_ROUND(X0, X1, X2, X3, X4, X5, X6, X7, X8, X9, X10, X11, X11, X13, X14)
+	SHUFFLE_INV(X2, X3, X4, X5, X6, X7, X8, X9)
+
+	LOAD_MSG(X8, X9, X10, X11, SI, 11, 12, 5, 15, 8, 0, 2, 13)
+	HALF_ROUND(X0, X1, X2, X3, X4, X5, X6, X7, X8, X9, X10, X11, X11, X13, X14)
+	SHUFFLE(X2, X3, X4, X5, X6, X7, X8, X9)
+	LOAD_MSG(X8, X9, X10, X11, SI, 10, 3, 7, 9, 14, 6, 1, 4)
+	HALF_ROUND(X0, X1, X2, X3, X4, X5, X6, X7, X8, X9, X10, X11, X11, X13, X14)
+	SHUFFLE_INV(X2, X3, X4, X5, X6, X7, X8, X9)
+
+	LOAD_MSG(X8, X9, X10, X11, SI, 7, 3, 13, 11, 9, 1, 12, 14)
+	HALF_ROUND(X0, X1, X2, X3, X4, X5, X6, X7, X8, X9, X10, X11, X11, X13, X14)
+	SHUFFLE(X2, X3, X4, X5, X6, X7, X8, X9)
+	LOAD_MSG(X8, X9, X10, X11, SI, 2, 5, 4, 15, 6, 10, 0, 8)
+	HALF_ROUND(X0, X1, X2, X3, X4, X5, X6, X7, X8, X9, X10, X11, X11, X13, X14)
+	SHUFFLE_INV(X2, X3, X4, X5, X6, X7, X8, X9)
+
+	LOAD_MSG(X8, X9, X10, X11, SI, 9, 5, 2, 10, 0, 7, 4, 15)
+	HALF_ROUND(X0, X1, X2, X3, X4, X5, X6, X7, X8, X9, X10, X11, X11, X13, X14)
+	SHUFFLE(X2, X3, X4, X5, X6, X7, X8, X9)
+	LOAD_MSG(X8, X9, X10, X11, SI, 14, 11, 6, 3, 1, 12, 8, 13)
+	HALF_ROUND(X0, X1, X2, X3, X4, X5, X6, X7, X8, X9, X10, X11, X11, X13, X14)
+	SHUFFLE_INV(X2, X3, X4, X5, X6, X7, X8, X9)
+
+	LOAD_MSG(X8, X9, X10, X11, SI, 2, 6, 0, 8, 12, 10, 11, 3)
+	HALF_ROUND(X0, X1, X2, X3, X4, X5, X6, X7, X8, X9, X10, X11, X11, X13, X14)
+	SHUFFLE(X2, X3, X4, X5, X6, X7, X8, X9)
+	LOAD_MSG(X8, X9, X10, X11, SI, 4, 7, 15, 1, 13, 5, 14, 9)
+	HALF_ROUND(X0, X1, X2, X3, X4, X5, X6, X7, X8, X9, X10, X11, X11, X13, X14)
+	SHUFFLE_INV(X2, X3, X4, X5, X6, X7, X8, X9)
+
+	LOAD_MSG(X8, X9, X10, X11, SI, 12, 1, 14, 4, 5, 15, 13, 10)
+	HALF_ROUND(X0, X1, X2, X3, X4, X5, X6, X7, X8, X9, X10, X11, X11, X13, X14)
+	SHUFFLE(X2, X3, X4, X5, X6, X7, X8, X9)
+	LOAD_MSG(X8, X9, X10, X11, SI, 0, 6, 9, 8, 7, 3, 2, 11)
+	HALF_ROUND(X0, X1, X2, X3, X4, X5, X6, X7, X8, X9, X10, X11, X11, X13, X14)
+	SHUFFLE_INV(X2, X3, X4, X5, X6, X7, X8, X9)
+
+	LOAD_MSG(X8, X9, X10, X11, SI, 13, 7, 12, 3, 11, 14, 1, 9)
+	HALF_ROUND(X0, X1, X2, X3, X4, X5, X6, X7, X8, X9, X10, X11, X11, X13, X14)
+	SHUFFLE(X2, X3, X4, X5, X6, X7, X8, X9)
+	LOAD_MSG(X8, X9, X10, X11, SI, 5, 15, 8, 2, 0, 4, 6, 10)
+	HALF_ROUND(X0, X1, X2, X3, X4, X5, X6, X7, X8, X9, X10, X11, X11, X13, X14)
+	SHUFFLE_INV(X2, X3, X4, X5, X6, X7, X8, X9)
+
+	LOAD_MSG(X8, X9, X10, X11, SI, 6, 14, 11, 0, 15, 9, 3, 8)
+	HALF_ROUND(X0, X1, X2, X3, X4, X5, X6, X7, X8, X9, X10, X11, X11, X13, X14)
+	SHUFFLE(X2, X3, X4, X5, X6, X7, X8, X9)
+	LOAD_MSG(X8, X9, X10, X11, SI, 12, 13, 1, 10, 2, 7, 4, 5)
+	HALF_ROUND(X0, X1, X2, X3, X4, X5, X6, X7, X8, X9, X10, X11, X11, X13, X14)
+	SHUFFLE_INV(X2, X3, X4, X5, X6, X7, X8, X9)
+
+	LOAD_MSG(X8, X9, X10, X11, SI, 10, 8, 7, 1, 2, 4, 6, 5)
+	HALF_ROUND(X0, X1, X2, X3, X4, X5, X6, X7, X8, X9, X10, X11, X11, X13, X14)
+	SHUFFLE(X2, X3, X4, X5, X6, X7, X8, X9)
+	LOAD_MSG(X8, X9, X10, X11, SI, 15, 9, 3, 13, 11, 14, 12, 0)
+	HALF_ROUND(X0, X1, X2, X3, X4, X5, X6, X7, X8, X9, X10, X11, X11, X13, X14)
+	SHUFFLE_INV(X2, X3, X4, X5, X6, X7, X8, X9)
+
+	HALF_ROUND(X0, X1, X2, X3, X4, X5, X6, X7, Mem{Base: R10}.Offset(16), Mem{Base: R10}.Offset(32), Mem{Base: R10}.Offset(48), Mem{Base: R10}.Offset(64), X11, X13, X14)
+	SHUFFLE(X2, X3, X4, X5, X6, X7, X8, X9)
+	HALF_ROUND(X0, X1, X2, X3, X4, X5, X6, X7, Mem{Base: R10}.Offset(80), Mem{Base: R10}.Offset(96), Mem{Base: R10}.Offset(112), Mem{Base: R10}.Offset(128), X11, X13, X14)
+	SHUFFLE_INV(X2, X3, X4, X5, X6, X7, X8, X9)
+
+	HALF_ROUND(X0, X1, X2, X3, X4, X5, X6, X7, Mem{Base: R10}.Offset(144), Mem{Base: R10}.Offset(160), Mem{Base: R10}.Offset(176), Mem{Base: R10}.Offset(192), X11, X13, X14)
+	SHUFFLE(X2, X3, X4, X5, X6, X7, X8, X9)
+	HALF_ROUND(X0, X1, X2, X3, X4, X5, X6, X7, Mem{Base: R10}.Offset(208), Mem{Base: R10}.Offset(224), Mem{Base: R10}.Offset(240), Mem{Base: R10}.Offset(256), X11, X13, X14)
+	SHUFFLE_INV(X2, X3, X4, X5, X6, X7, X8, X9)
+
+	MOVOU(Mem{Base: AX}.Offset(32), X10)
+	MOVOU(Mem{Base: AX}.Offset(48), X11)
+	PXOR(X0, X12)
+	PXOR(X1, X15)
+	PXOR(X2, X10)
+	PXOR(X3, X11)
+	PXOR(X4, X12)
+	PXOR(X5, X15)
+	PXOR(X6, X10)
+	PXOR(X7, X11)
+	MOVOU(X10, Mem{Base: AX}.Offset(32))
+	MOVOU(X11, Mem{Base: AX}.Offset(48))
+
+	LEAQ(Mem{Base: SI}.Offset(128), RSI)
+	SUBQ(Imm(128), RDI)
+	JNE(LabelRef("loop"))
+
+	MOVOU(X12, Mem{Base: AX}.Offset(0))
+	MOVOU(X15, Mem{Base: AX}.Offset(16))
+
+	MOVQ(R8, Mem{Base: BX}.Offset(0))
+	MOVQ(R9, Mem{Base: BX}.Offset(8))
+
+	RET()
+}
+
+// #~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~DATA SECTION~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~##
+
+func iv0_DATA() Mem {
+	if iv0_DATA_ptr != nil {
+		return *iv0_DATA_ptr
+	}
+
+	iv0 := GLOBL(ThatPeskyUnicodeDot+"iv0", NOPTR|RODATA)
+	iv0_DATA_ptr = &iv0
+	DATA(0x00, U64(0x6a09e667f3bcc908))
+	DATA(0x08, U64(0xbb67ae8584caa73b))
+	return iv0
+}
+
+func iv1_DATA() Mem {
+	if iv1_DATA_ptr != nil {
+		return *iv1_DATA_ptr
+	}
+
+	iv1 := GLOBL(ThatPeskyUnicodeDot+"iv1", NOPTR|RODATA)
+	iv1_DATA_ptr = &iv1
+	DATA(0x00, U64(0x3c6ef372fe94f82b))
+	DATA(0x08, U64(0xa54ff53a5f1d36f1))
+	return iv1
+}
+
+func iv2_DATA() Mem {
+	if iv2_DATA_ptr != nil {
+		return *iv2_DATA_ptr
+	}
+
+	iv2 := GLOBL(ThatPeskyUnicodeDot+"iv2", NOPTR|RODATA)
+	iv2_DATA_ptr = &iv2
+	DATA(0x00, U64(0x510e527fade682d1))
+	DATA(0x08, U64(0x9b05688c2b3e6c1f))
+	return iv2
+}
+
+func iv3_DATA() Mem {
+	if iv3_DATA_ptr != nil {
+		return *iv3_DATA_ptr
+	}
+
+	iv3 := GLOBL(ThatPeskyUnicodeDot+"iv3", NOPTR|RODATA)
+	iv3_DATA_ptr = &iv3
+	DATA(0x00, U64(0x1f83d9abfb41bd6b))
+	DATA(0x08, U64(0x5be0cd19137e2179))
+	return iv3
+}
+
+func c40_DATA() Mem {
+	if c40_DATA_ptr != nil {
+		return *c40_DATA_ptr
+	}
+
+	c40 := GLOBL(ThatPeskyUnicodeDot+"c40", NOPTR|RODATA)
+	c40_DATA_ptr = &c40
+	DATA(0x00, U64(0x0201000706050403))
+	DATA(0x08, U64(0x0a09080f0e0d0c0b))
+	return c40
+}
+
+func c48_DATA() Mem {
+	if c48_DATA_ptr != nil {
+		return *c48_DATA_ptr
+	}
+
+	c48 := GLOBL(ThatPeskyUnicodeDot+"c48", NOPTR|RODATA)
+	c48_DATA_ptr = &c48
+	DATA(0x00, U64(0x0100070605040302))
+	DATA(0x08, U64(0x09080f0e0d0c0b0a))
+	return c48
+}

blake2b/_asm/standard/go.mod

@@ -0,0 +1,15 @@
+module blake2b/_asm
+
+go 1.23
+
+require (
+	github.com/mmcloughlin/avo v0.6.0
+	golang.org/x/crypto v0.33.0
+)
+
+require (
+	golang.org/x/mod v0.20.0 // indirect
+	golang.org/x/sync v0.8.0 // indirect
+	golang.org/x/sys v0.30.0 // indirect
+	golang.org/x/tools v0.24.0 // indirect
+)

blake2b/_asm/standard/go.sum

@@ -0,0 +1,12 @@
+github.com/mmcloughlin/avo v0.6.0 h1:QH6FU8SKoTLaVs80GA8TJuLNkUYl4VokHKlPhVDg4YY=
+github.com/mmcloughlin/avo v0.6.0/go.mod h1:8CoAGaCSYXtCPR+8y18Y9aB/kxb8JSS6FRI7mSkvD+8=
+golang.org/x/crypto v0.33.0 h1:IOBPskki6Lysi0lo9qQvbxiQ+FvsCC/YWOecCHAixus=
+golang.org/x/crypto v0.33.0/go.mod h1:bVdXmD7IV/4GdElGPozy6U7lWdRXA4qyRVGJV57uQ5M=
+golang.org/x/mod v0.20.0 h1:utOm6MM3R3dnawAiJgn0y+xvuYRsm1RKM/4giyfDgV0=
+golang.org/x/mod v0.20.0/go.mod h1:hTbmBsO62+eylJbnUtE2MGJUyE7QWk4xUqPFrRgJ+7c=
+golang.org/x/sync v0.8.0 h1:3NFvSEYkUoMifnESzZl15y791HH1qU2xm6eCJU5ZPXQ=
+golang.org/x/sync v0.8.0/go.mod h1:Czt+wKu1gCyEFDUtn0jG5QVvpJ6rzVqr5aXyt9drQfk=
+golang.org/x/sys v0.30.0 h1:QjkSwP/36a20jFYWkSue1YwXzLmsV5Gfq7Eiy72C1uc=
+golang.org/x/sys v0.30.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
+golang.org/x/tools v0.24.0 h1:J1shsA93PJUEVaUSaay7UXAyE8aimq3GW0pjlolpa24=
+golang.org/x/tools v0.24.0/go.mod h1:YhNqVBIfWHdzvTLs0d8LCuMhkKUgSUKldakyV7W/WDQ=

blake2b/blake2x.go

@@ -12,6 +12,8 @@ import (
 
 // XOF defines the interface to hash functions that
 // support arbitrary-length output.
+//
+// New callers should prefer the standard library [hash.XOF].
 type XOF interface {
 	// Write absorbs more data into the hash's state. It panics if called
 	// after Read.
@@ -47,6 +49,8 @@ const maxOutputLength = (1 << 32) * 64
 //
 // A non-nil key turns the hash into a MAC. The key must between
 // zero and 32 bytes long.
+//
+// The result can be safely interface-upgraded to [hash.XOF].
 func NewXOF(size uint32, key []byte) (XOF, error) {
 	if len(key) > Size {
 		return nil, errKeySize
@@ -93,6 +97,10 @@ func (x *xof) Clone() XOF {
 	return &clone
 }
 
+func (x *xof) BlockSize() int {
+	return x.d.BlockSize()
+}
+
 func (x *xof) Reset() {
 	x.cfg[0] = byte(Size)
 	binary.LittleEndian.PutUint32(x.cfg[4:], uint32(Size)) // leaf length

blake2b/go125.go

@@ -0,0 +1,11 @@
+// Copyright 2025 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build go1.25
+
+package blake2b
+
+import "hash"
+
+var _ hash.XOF = (*xof)(nil)

blake2s/_asm/blake2s_amd64_asm.go

@@ -0,0 +1,525 @@
+// Copyright 2024 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package main
+
+import (
+	. "github.com/mmcloughlin/avo/build"
+	"github.com/mmcloughlin/avo/ir"
+	. "github.com/mmcloughlin/avo/operand"
+	. "github.com/mmcloughlin/avo/reg"
+	_ "golang.org/x/crypto/blake2s"
+)
+
+//go:generate go run . -out ../blake2s_amd64.s -pkg blake2s
+
+func main() {
+	Package("golang.org/x/crypto/blake2s")
+	ConstraintExpr("amd64,gc,!purego")
+	hashBlocksSSE2()
+	hashBlocksSSSE3()
+	hashBlocksSSE4()
+	Generate()
+}
+
+func ROTL_SSE2(n uint64, t, v VecPhysical) {
+	MOVO(v, t)
+	PSLLL(Imm(n), t)
+	PSRLL(Imm(32-n), v)
+	PXOR(t, v)
+}
+
+func ROTL_SSSE3(c, v VecPhysical) {
+	PSHUFB(c, v)
+}
+
+func ROUND_SSE2(v0, v1, v2, v3 VecPhysical, m0, m1, m2, m3 Mem, t VecPhysical) {
+	PADDL(m0, v0)
+	PADDL(v1, v0)
+	PXOR(v0, v3)
+	ROTL_SSE2(16, t, v3)
+	PADDL(v3, v2)
+	PXOR(v2, v1)
+	ROTL_SSE2(20, t, v1)
+	PADDL(m1, v0)
+	PADDL(v1, v0)
+	PXOR(v0, v3)
+	ROTL_SSE2(24, t, v3)
+	PADDL(v3, v2)
+	PXOR(v2, v1)
+	ROTL_SSE2(25, t, v1)
+	PSHUFL(Imm(0x39), v1, v1)
+	PSHUFL(Imm(0x4E), v2, v2)
+	PSHUFL(Imm(0x93), v3, v3)
+	PADDL(m2, v0)
+	PADDL(v1, v0)
+	PXOR(v0, v3)
+	ROTL_SSE2(16, t, v3)
+	PADDL(v3, v2)
+	PXOR(v2, v1)
+	ROTL_SSE2(20, t, v1)
+	PADDL(m3, v0)
+	PADDL(v1, v0)
+	PXOR(v0, v3)
+	ROTL_SSE2(24, t, v3)
+	PADDL(v3, v2)
+	PXOR(v2, v1)
+	ROTL_SSE2(25, t, v1)
+	PSHUFL(Imm(0x39), v3, v3)
+	PSHUFL(Imm(0x4E), v2, v2)
+	PSHUFL(Imm(0x93), v1, v1)
+}
+
+func ROUND_SSSE3(v0, v1, v2, v3 VecPhysical, m0, m1, m2, m3 Op, t, c16, c8 VecPhysical) {
+	PADDL(m0, v0)
+	PADDL(v1, v0)
+	PXOR(v0, v3)
+	ROTL_SSSE3(c16, v3)
+	PADDL(v3, v2)
+	PXOR(v2, v1)
+	ROTL_SSE2(20, t, v1)
+	PADDL(m1, v0)
+	PADDL(v1, v0)
+	PXOR(v0, v3)
+	ROTL_SSSE3(c8, v3)
+	PADDL(v3, v2)
+	PXOR(v2, v1)
+	ROTL_SSE2(25, t, v1)
+	PSHUFL(Imm(0x39), v1, v1)
+	PSHUFL(Imm(0x4E), v2, v2)
+	PSHUFL(Imm(0x93), v3, v3)
+	PADDL(m2, v0)
+	PADDL(v1, v0)
+	PXOR(v0, v3)
+	ROTL_SSSE3(c16, v3)
+	PADDL(v3, v2)
+	PXOR(v2, v1)
+	ROTL_SSE2(20, t, v1)
+	PADDL(m3, v0)
+	PADDL(v1, v0)
+	PXOR(v0, v3)
+	ROTL_SSSE3(c8, v3)
+	PADDL(v3, v2)
+	PXOR(v2, v1)
+	ROTL_SSE2(25, t, v1)
+	PSHUFL(Imm(0x39), v3, v3)
+	PSHUFL(Imm(0x4E), v2, v2)
+	PSHUFL(Imm(0x93), v1, v1)
+}
+
+func LOAD_MSG_SSE4(m0, m1, m2, m3 VecPhysical, src GPPhysical, i0, i1, i2, i3, i4, i5, i6, i7, i8, i9, i10, i11, i12, i13, i14, i15 int) {
+	// Hack to get Avo to emit a MOVL instruction with a VecPhysical as the destination
+	Instruction(&ir.Instruction{Opcode: "MOVL", Operands: []Op{Mem{Base: src}.Offset(i0 * 4), m0}})
+	PINSRD(Imm(1), Mem{Base: src}.Offset(i1*4), m0)
+	PINSRD(Imm(2), Mem{Base: src}.Offset(i2*4), m0)
+	PINSRD(Imm(3), Mem{Base: src}.Offset(i3*4), m0)
+	Instruction(&ir.Instruction{Opcode: "MOVL", Operands: []Op{Mem{Base: src}.Offset(i4 * 4), m1}})
+	PINSRD(Imm(1), Mem{Base: src}.Offset(i5*4), m1)
+	PINSRD(Imm(2), Mem{Base: src}.Offset(i6*4), m1)
+	PINSRD(Imm(3), Mem{Base: src}.Offset(i7*4), m1)
+	Instruction(&ir.Instruction{Opcode: "MOVL", Operands: []Op{Mem{Base: src}.Offset(i8 * 4), m2}})
+	PINSRD(Imm(1), Mem{Base: src}.Offset(i9*4), m2)
+	PINSRD(Imm(2), Mem{Base: src}.Offset(i10*4), m2)
+	PINSRD(Imm(3), Mem{Base: src}.Offset(i11*4), m2)
+	Instruction(&ir.Instruction{Opcode: "MOVL", Operands: []Op{Mem{Base: src}.Offset(i12 * 4), m3}})
+	PINSRD(Imm(1), Mem{Base: src}.Offset(i13*4), m3)
+	PINSRD(Imm(2), Mem{Base: src}.Offset(i14*4), m3)
+	PINSRD(Imm(3), Mem{Base: src}.Offset(i15*4), m3)
+}
+
+func PRECOMPUTE_MSG(dst GPPhysical, off int, src, R8, R9, R10, R11, R12, R13, R14, R15 GPPhysical) {
+	MOVQ(Mem{Base: src}.Offset(0*4), R8)
+	MOVQ(Mem{Base: src}.Offset(2*4), R9)
+	MOVQ(Mem{Base: src}.Offset(4*4), R10)
+	MOVQ(Mem{Base: src}.Offset(6*4), R11)
+	MOVQ(Mem{Base: src}.Offset(8*4), R12)
+	MOVQ(Mem{Base: src}.Offset(10*4), R13)
+	MOVQ(Mem{Base: src}.Offset(12*4), R14)
+	MOVQ(Mem{Base: src}.Offset(14*4), R15)
+
+	MOVL(R8L, Mem{Base: dst}.Offset(0*4+off+0))
+	MOVL(R8L, Mem{Base: dst}.Offset(9*4+off+64))
+	MOVL(R8L, Mem{Base: dst}.Offset(5*4+off+128))
+	MOVL(R8L, Mem{Base: dst}.Offset(14*4+off+192))
+	MOVL(R8L, Mem{Base: dst}.Offset(4*4+off+256))
+	MOVL(R8L, Mem{Base: dst}.Offset(2*4+off+320))
+	MOVL(R8L, Mem{Base: dst}.Offset(8*4+off+384))
+	MOVL(R8L, Mem{Base: dst}.Offset(12*4+off+448))
+	MOVL(R8L, Mem{Base: dst}.Offset(3*4+off+512))
+	MOVL(R8L, Mem{Base: dst}.Offset(15*4+off+576))
+	SHRQ(Imm(32), R8)
+	MOVL(R8L, Mem{Base: dst}.Offset(4*4+off+0))
+	MOVL(R8L, Mem{Base: dst}.Offset(8*4+off+64))
+	MOVL(R8L, Mem{Base: dst}.Offset(14*4+off+128))
+	MOVL(R8L, Mem{Base: dst}.Offset(5*4+off+192))
+	MOVL(R8L, Mem{Base: dst}.Offset(12*4+off+256))
+	MOVL(R8L, Mem{Base: dst}.Offset(11*4+off+320))
+	MOVL(R8L, Mem{Base: dst}.Offset(1*4+off+384))
+	MOVL(R8L, Mem{Base: dst}.Offset(6*4+off+448))
+	MOVL(R8L, Mem{Base: dst}.Offset(10*4+off+512))
+	MOVL(R8L, Mem{Base: dst}.Offset(3*4+off+576))
+
+	MOVL(R9L, Mem{Base: dst}.Offset(1*4+off+0))
+	MOVL(R9L, Mem{Base: dst}.Offset(13*4+off+64))
+	MOVL(R9L, Mem{Base: dst}.Offset(6*4+off+128))
+	MOVL(R9L, Mem{Base: dst}.Offset(8*4+off+192))
+	MOVL(R9L, Mem{Base: dst}.Offset(2*4+off+256))
+	MOVL(R9L, Mem{Base: dst}.Offset(0*4+off+320))
+	MOVL(R9L, Mem{Base: dst}.Offset(14*4+off+384))
+	MOVL(R9L, Mem{Base: dst}.Offset(11*4+off+448))
+	MOVL(R9L, Mem{Base: dst}.Offset(12*4+off+512))
+	MOVL(R9L, Mem{Base: dst}.Offset(4*4+off+576))
+	SHRQ(Imm(32), R9)
+	MOVL(R9L, Mem{Base: dst}.Offset(5*4+off+0))
+	MOVL(R9L, Mem{Base: dst}.Offset(15*4+off+64))
+	MOVL(R9L, Mem{Base: dst}.Offset(9*4+off+128))
+	MOVL(R9L, Mem{Base: dst}.Offset(1*4+off+192))
+	MOVL(R9L, Mem{Base: dst}.Offset(11*4+off+256))
+	MOVL(R9L, Mem{Base: dst}.Offset(7*4+off+320))
+	MOVL(R9L, Mem{Base: dst}.Offset(13*4+off+384))
+	MOVL(R9L, Mem{Base: dst}.Offset(3*4+off+448))
+	MOVL(R9L, Mem{Base: dst}.Offset(6*4+off+512))
+	MOVL(R9L, Mem{Base: dst}.Offset(10*4+off+576))
+
+	MOVL(R10L, Mem{Base: dst}.Offset(2*4+off+0))
+	MOVL(R10L, Mem{Base: dst}.Offset(1*4+off+64))
+	MOVL(R10L, Mem{Base: dst}.Offset(15*4+off+128))
+	MOVL(R10L, Mem{Base: dst}.Offset(10*4+off+192))
+	MOVL(R10L, Mem{Base: dst}.Offset(6*4+off+256))
+	MOVL(R10L, Mem{Base: dst}.Offset(8*4+off+320))
+	MOVL(R10L, Mem{Base: dst}.Offset(3*4+off+384))
+	MOVL(R10L, Mem{Base: dst}.Offset(13*4+off+448))
+	MOVL(R10L, Mem{Base: dst}.Offset(14*4+off+512))
+	MOVL(R10L, Mem{Base: dst}.Offset(5*4+off+576))
+	SHRQ(Imm(32), R10)
+	MOVL(R10L, Mem{Base: dst}.Offset(6*4+off+0))
+	MOVL(R10L, Mem{Base: dst}.Offset(11*4+off+64))
+	MOVL(R10L, Mem{Base: dst}.Offset(2*4+off+128))
+	MOVL(R10L, Mem{Base: dst}.Offset(9*4+off+192))
+	MOVL(R10L, Mem{Base: dst}.Offset(1*4+off+256))
+	MOVL(R10L, Mem{Base: dst}.Offset(13*4+off+320))
+	MOVL(R10L, Mem{Base: dst}.Offset(4*4+off+384))
+	MOVL(R10L, Mem{Base: dst}.Offset(8*4+off+448))
+	MOVL(R10L, Mem{Base: dst}.Offset(15*4+off+512))
+	MOVL(R10L, Mem{Base: dst}.Offset(7*4+off+576))
+
+	MOVL(R11L, Mem{Base: dst}.Offset(3*4+off+0))
+	MOVL(R11L, Mem{Base: dst}.Offset(7*4+off+64))
+	MOVL(R11L, Mem{Base: dst}.Offset(13*4+off+128))
+	MOVL(R11L, Mem{Base: dst}.Offset(12*4+off+192))
+	MOVL(R11L, Mem{Base: dst}.Offset(10*4+off+256))
+	MOVL(R11L, Mem{Base: dst}.Offset(1*4+off+320))
+	MOVL(R11L, Mem{Base: dst}.Offset(9*4+off+384))
+	MOVL(R11L, Mem{Base: dst}.Offset(14*4+off+448))
+	MOVL(R11L, Mem{Base: dst}.Offset(0*4+off+512))
+	MOVL(R11L, Mem{Base: dst}.Offset(6*4+off+576))
+	SHRQ(Imm(32), R11)
+	MOVL(R11L, Mem{Base: dst}.Offset(7*4+off+0))
+	MOVL(R11L, Mem{Base: dst}.Offset(14*4+off+64))
+	MOVL(R11L, Mem{Base: dst}.Offset(10*4+off+128))
+	MOVL(R11L, Mem{Base: dst}.Offset(0*4+off+192))
+	MOVL(R11L, Mem{Base: dst}.Offset(5*4+off+256))
+	MOVL(R11L, Mem{Base: dst}.Offset(9*4+off+320))
+	MOVL(R11L, Mem{Base: dst}.Offset(12*4+off+384))
+	MOVL(R11L, Mem{Base: dst}.Offset(1*4+off+448))
+	MOVL(R11L, Mem{Base: dst}.Offset(13*4+off+512))
+	MOVL(R11L, Mem{Base: dst}.Offset(2*4+off+576))
+
+	MOVL(R12L, Mem{Base: dst}.Offset(8*4+off+0))
+	MOVL(R12L, Mem{Base: dst}.Offset(5*4+off+64))
+	MOVL(R12L, Mem{Base: dst}.Offset(4*4+off+128))
+	MOVL(R12L, Mem{Base: dst}.Offset(15*4+off+192))
+	MOVL(R12L, Mem{Base: dst}.Offset(14*4+off+256))
+	MOVL(R12L, Mem{Base: dst}.Offset(3*4+off+320))
+	MOVL(R12L, Mem{Base: dst}.Offset(11*4+off+384))
+	MOVL(R12L, Mem{Base: dst}.Offset(10*4+off+448))
+	MOVL(R12L, Mem{Base: dst}.Offset(7*4+off+512))
+	MOVL(R12L, Mem{Base: dst}.Offset(1*4+off+576))
+	SHRQ(Imm(32), R12)
+	MOVL(R12L, Mem{Base: dst}.Offset(12*4+off+0))
+	MOVL(R12L, Mem{Base: dst}.Offset(2*4+off+64))
+	MOVL(R12L, Mem{Base: dst}.Offset(11*4+off+128))
+	MOVL(R12L, Mem{Base: dst}.Offset(4*4+off+192))
+	MOVL(R12L, Mem{Base: dst}.Offset(0*4+off+256))
+	MOVL(R12L, Mem{Base: dst}.Offset(15*4+off+320))
+	MOVL(R12L, Mem{Base: dst}.Offset(10*4+off+384))
+	MOVL(R12L, Mem{Base: dst}.Offset(7*4+off+448))
+	MOVL(R12L, Mem{Base: dst}.Offset(5*4+off+512))
+	MOVL(R12L, Mem{Base: dst}.Offset(9*4+off+576))
+
+	MOVL(R13L, Mem{Base: dst}.Offset(9*4+off+0))
+	MOVL(R13L, Mem{Base: dst}.Offset(4*4+off+64))
+	MOVL(R13L, Mem{Base: dst}.Offset(8*4+off+128))
+	MOVL(R13L, Mem{Base: dst}.Offset(13*4+off+192))
+	MOVL(R13L, Mem{Base: dst}.Offset(3*4+off+256))
+	MOVL(R13L, Mem{Base: dst}.Offset(5*4+off+320))
+	MOVL(R13L, Mem{Base: dst}.Offset(7*4+off+384))
+	MOVL(R13L, Mem{Base: dst}.Offset(15*4+off+448))
+	MOVL(R13L, Mem{Base: dst}.Offset(11*4+off+512))
+	MOVL(R13L, Mem{Base: dst}.Offset(0*4+off+576))
+	SHRQ(Imm(32), R13)
+	MOVL(R13L, Mem{Base: dst}.Offset(13*4+off+0))
+	MOVL(R13L, Mem{Base: dst}.Offset(10*4+off+64))
+	MOVL(R13L, Mem{Base: dst}.Offset(0*4+off+128))
+	MOVL(R13L, Mem{Base: dst}.Offset(3*4+off+192))
+	MOVL(R13L, Mem{Base: dst}.Offset(9*4+off+256))
+	MOVL(R13L, Mem{Base: dst}.Offset(6*4+off+320))
+	MOVL(R13L, Mem{Base: dst}.Offset(15*4+off+384))
+	MOVL(R13L, Mem{Base: dst}.Offset(4*4+off+448))
+	MOVL(R13L, Mem{Base: dst}.Offset(2*4+off+512))
+	MOVL(R13L, Mem{Base: dst}.Offset(12*4+off+576))
+
+	MOVL(R14L, Mem{Base: dst}.Offset(10*4+off+0))
+	MOVL(R14L, Mem{Base: dst}.Offset(12*4+off+64))
+	MOVL(R14L, Mem{Base: dst}.Offset(1*4+off+128))
+	MOVL(R14L, Mem{Base: dst}.Offset(6*4+off+192))
+	MOVL(R14L, Mem{Base: dst}.Offset(13*4+off+256))
+	MOVL(R14L, Mem{Base: dst}.Offset(4*4+off+320))
+	MOVL(R14L, Mem{Base: dst}.Offset(0*4+off+384))
+	MOVL(R14L, Mem{Base: dst}.Offset(2*4+off+448))
+	MOVL(R14L, Mem{Base: dst}.Offset(8*4+off+512))
+	MOVL(R14L, Mem{Base: dst}.Offset(14*4+off+576))
+	SHRQ(Imm(32), R14)
+	MOVL(R14L, Mem{Base: dst}.Offset(14*4+off+0))
+	MOVL(R14L, Mem{Base: dst}.Offset(3*4+off+64))
+	MOVL(R14L, Mem{Base: dst}.Offset(7*4+off+128))
+	MOVL(R14L, Mem{Base: dst}.Offset(2*4+off+192))
+	MOVL(R14L, Mem{Base: dst}.Offset(15*4+off+256))
+	MOVL(R14L, Mem{Base: dst}.Offset(12*4+off+320))
+	MOVL(R14L, Mem{Base: dst}.Offset(6*4+off+384))
+	MOVL(R14L, Mem{Base: dst}.Offset(0*4+off+448))
+	MOVL(R14L, Mem{Base: dst}.Offset(9*4+off+512))
+	MOVL(R14L, Mem{Base: dst}.Offset(11*4+off+576))
+
+	MOVL(R15L, Mem{Base: dst}.Offset(11*4+off+0))
+	MOVL(R15L, Mem{Base: dst}.Offset(0*4+off+64))
+	MOVL(R15L, Mem{Base: dst}.Offset(12*4+off+128))
+	MOVL(R15L, Mem{Base: dst}.Offset(7*4+off+192))
+	MOVL(R15L, Mem{Base: dst}.Offset(8*4+off+256))
+	MOVL(R15L, Mem{Base: dst}.Offset(14*4+off+320))
+	MOVL(R15L, Mem{Base: dst}.Offset(2*4+off+384))
+	MOVL(R15L, Mem{Base: dst}.Offset(5*4+off+448))
+	MOVL(R15L, Mem{Base: dst}.Offset(1*4+off+512))
+	MOVL(R15L, Mem{Base: dst}.Offset(13*4+off+576))
+	SHRQ(Imm(32), R15)
+	MOVL(R15L, Mem{Base: dst}.Offset(15*4+off+0))
+	MOVL(R15L, Mem{Base: dst}.Offset(6*4+off+64))
+	MOVL(R15L, Mem{Base: dst}.Offset(3*4+off+128))
+	MOVL(R15L, Mem{Base: dst}.Offset(11*4+off+192))
+	MOVL(R15L, Mem{Base: dst}.Offset(7*4+off+256))
+	MOVL(R15L, Mem{Base: dst}.Offset(10*4+off+320))
+	MOVL(R15L, Mem{Base: dst}.Offset(5*4+off+384))
+	MOVL(R15L, Mem{Base: dst}.Offset(9*4+off+448))
+	MOVL(R15L, Mem{Base: dst}.Offset(4*4+off+512))
+	MOVL(R15L, Mem{Base: dst}.Offset(8*4+off+576))
+}
+
+func BLAKE2s_SSE2() {
+	PRECOMPUTE_MSG(BP, 16, SI, R8, R9, R10, R11, R12, R13, R14, R15)
+	for i := 0; i < 10; i++ {
+		ROUND_SSE2(X4, X5, X6, X7, Mem{Base: BP}.Offset(16+64*i), Mem{Base: BP}.Offset(32+64*i), Mem{Base: BP}.Offset(48+64*i), Mem{Base: BP}.Offset(64+64*i), X8)
+	}
+}
+
+func BLAKE2s_SSSE3() {
+	PRECOMPUTE_MSG(BP, 16, SI, R8, R9, R10, R11, R12, R13, R14, R15)
+	for i := 0; i < 10; i++ {
+		ROUND_SSSE3(X4, X5, X6, X7, Mem{Base: BP}.Offset(16+64*i), Mem{Base: BP}.Offset(32+64*i), Mem{Base: BP}.Offset(48+64*i), Mem{Base: BP}.Offset(64+64*i), X8, X13, X14)
+	}
+}
+
+func BLAKE2s_SSE4() {
+	LOAD_MSG_SSE4(X8, X9, X10, X11, SI, 0, 2, 4, 6, 1, 3, 5, 7, 8, 10, 12, 14, 9, 11, 13, 15)
+	ROUND_SSSE3(X4, X5, X6, X7, X8, X9, X10, X11, X8, X13, X14)
+	LOAD_MSG_SSE4(X8, X9, X10, X11, SI, 14, 4, 9, 13, 10, 8, 15, 6, 1, 0, 11, 5, 12, 2, 7, 3)
+	ROUND_SSSE3(X4, X5, X6, X7, X8, X9, X10, X11, X8, X13, X14)
+	LOAD_MSG_SSE4(X8, X9, X10, X11, SI, 11, 12, 5, 15, 8, 0, 2, 13, 10, 3, 7, 9, 14, 6, 1, 4)
+	ROUND_SSSE3(X4, X5, X6, X7, X8, X9, X10, X11, X8, X13, X14)
+	LOAD_MSG_SSE4(X8, X9, X10, X11, SI, 7, 3, 13, 11, 9, 1, 12, 14, 2, 5, 4, 15, 6, 10, 0, 8)
+	ROUND_SSSE3(X4, X5, X6, X7, X8, X9, X10, X11, X8, X13, X14)
+	LOAD_MSG_SSE4(X8, X9, X10, X11, SI, 9, 5, 2, 10, 0, 7, 4, 15, 14, 11, 6, 3, 1, 12, 8, 13)
+	ROUND_SSSE3(X4, X5, X6, X7, X8, X9, X10, X11, X8, X13, X14)
+	LOAD_MSG_SSE4(X8, X9, X10, X11, SI, 2, 6, 0, 8, 12, 10, 11, 3, 4, 7, 15, 1, 13, 5, 14, 9)
+	ROUND_SSSE3(X4, X5, X6, X7, X8, X9, X10, X11, X8, X13, X14)
+	LOAD_MSG_SSE4(X8, X9, X10, X11, SI, 12, 1, 14, 4, 5, 15, 13, 10, 0, 6, 9, 8, 7, 3, 2, 11)
+	ROUND_SSSE3(X4, X5, X6, X7, X8, X9, X10, X11, X8, X13, X14)
+	LOAD_MSG_SSE4(X8, X9, X10, X11, SI, 13, 7, 12, 3, 11, 14, 1, 9, 5, 15, 8, 2, 0, 4, 6, 10)
+	ROUND_SSSE3(X4, X5, X6, X7, X8, X9, X10, X11, X8, X13, X14)
+	LOAD_MSG_SSE4(X8, X9, X10, X11, SI, 6, 14, 11, 0, 15, 9, 3, 8, 12, 13, 1, 10, 2, 7, 4, 5)
+	ROUND_SSSE3(X4, X5, X6, X7, X8, X9, X10, X11, X8, X13, X14)
+	LOAD_MSG_SSE4(X8, X9, X10, X11, SI, 10, 8, 7, 1, 2, 4, 6, 5, 15, 9, 3, 13, 11, 14, 12, 0)
+	ROUND_SSSE3(X4, X5, X6, X7, X8, X9, X10, X11, X8, X13, X14)
+}
+
+func HASH_BLOCKS(h, c, flag, blocks_base, blocks_len Mem, BLAKE2s_FUNC func()) {
+	MOVQ(h, RAX)
+	MOVQ(c, RBX)
+	MOVL(flag, ECX)
+	MOVQ(blocks_base, RSI)
+	MOVQ(blocks_len, RDX)
+
+	MOVQ(RSP, RBP)
+	ADDQ(Imm(15), RBP)
+	ANDQ(I32(^15), RBP)
+
+	MOVQ(Mem{Base: BX}.Offset(0), R9)
+	MOVQ(R9, Mem{Base: BP}.Offset(0))
+	MOVQ(RCX, Mem{Base: BP}.Offset(8))
+
+	MOVOU(Mem{Base: AX}.Offset(0), X0)
+	MOVOU(Mem{Base: AX}.Offset(16), X1)
+
+	iv0 := iv0_DATA()
+	iv1 := iv1_DATA()
+	MOVOU(iv0, X2)
+	MOVOU(iv1, X3)
+
+	counter := counter_DATA()
+	rol16 := rol16_DATA()
+	rol8 := rol8_DATA()
+	MOVOU(counter, X12)
+	MOVOU(rol16, X13)
+	MOVOU(rol8, X14)
+	MOVO(Mem{Base: BP}.Offset(0), X15)
+
+	Label("loop")
+	MOVO(X0, X4)
+	MOVO(X1, X5)
+	MOVO(X2, X6)
+	MOVO(X3, X7)
+
+	PADDQ(X12, X15)
+	PXOR(X15, X7)
+
+	BLAKE2s_FUNC()
+
+	PXOR(X4, X0)
+	PXOR(X5, X1)
+	PXOR(X6, X0)
+	PXOR(X7, X1)
+
+	LEAQ(Mem{Base: SI}.Offset(64), RSI)
+	SUBQ(Imm(64), RDX)
+	JNE(LabelRef("loop"))
+
+	MOVO(X15, Mem{Base: BP}.Offset(0))
+	MOVQ(Mem{Base: BP}.Offset(0), R9)
+	MOVQ(R9, Mem{Base: BX}.Offset(0))
+
+	MOVOU(X0, Mem{Base: AX}.Offset(0))
+	MOVOU(X1, Mem{Base: AX}.Offset(16))
+}
+
+func hashBlocksSSE2() {
+	Implement("hashBlocksSSE2")
+	Attributes(0)
+	AllocLocal(672) // frame = 656 + 16 byte alignment
+
+	h := NewParamAddr("h", 0)
+	c := NewParamAddr("c", 8)
+	flag := NewParamAddr("flag", 16)
+	blocks_base := NewParamAddr("blocks_base", 24)
+	blocks_len := NewParamAddr("blocks_len", 32)
+
+	HASH_BLOCKS(h, c, flag, blocks_base, blocks_len, BLAKE2s_SSE2)
+	RET()
+}
+
+func hashBlocksSSSE3() {
+	Implement("hashBlocksSSSE3")
+	Attributes(0)
+	AllocLocal(672) // frame = 656 + 16 byte alignment
+
+	h := NewParamAddr("h", 0)
+	c := NewParamAddr("c", 8)
+	flag := NewParamAddr("flag", 16)
+	blocks_base := NewParamAddr("blocks_base", 24)
+	blocks_len := NewParamAddr("blocks_len", 32)
+
+	HASH_BLOCKS(h, c, flag, blocks_base, blocks_len, BLAKE2s_SSSE3)
+	RET()
+}
+
+func hashBlocksSSE4() {
+	Implement("hashBlocksSSE4")
+	Attributes(0)
+	AllocLocal(32) // frame = 16 + 16 byte alignment
+
+	h := NewParamAddr("h", 0)
+	c := NewParamAddr("c", 8)
+	flag := NewParamAddr("flag", 16)
+	blocks_base := NewParamAddr("blocks_base", 24)
+	blocks_len := NewParamAddr("blocks_len", 32)
+
+	HASH_BLOCKS(h, c, flag, blocks_base, blocks_len, BLAKE2s_SSE4)
+	RET()
+}
+
+// ##~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~DATA SECTION~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~##
+
+var iv0_DATA_ptr, iv1_DATA_ptr, rol16_DATA_ptr, rol8_DATA_ptr, counter_DATA_ptr *Mem
+
+func iv0_DATA() Mem {
+	if iv0_DATA_ptr != nil {
+		return *iv0_DATA_ptr
+	}
+
+	iv0_DATA := GLOBL("iv0", NOPTR|RODATA)
+	iv0_DATA_ptr = &iv0_DATA
+	DATA(0x00, U32(0x6a09e667))
+	DATA(0x04, U32(0xbb67ae85))
+	DATA(0x08, U32(0x3c6ef372))
+	DATA(0x0c, U32(0xa54ff53a))
+	return iv0_DATA
+}
+
+func iv1_DATA() Mem {
+	if iv1_DATA_ptr != nil {
+		return *iv1_DATA_ptr
+	}
+
+	iv1_DATA := GLOBL("iv1", NOPTR|RODATA)
+	iv1_DATA_ptr = &iv1_DATA
+	DATA(0x00, U32(0x510e527f))
+	DATA(0x04, U32(0x9b05688c))
+	DATA(0x08, U32(0x1f83d9ab))
+	DATA(0x0c, U32(0x5be0cd19))
+	return iv1_DATA
+}
+
+func rol16_DATA() Mem {
+	if rol16_DATA_ptr != nil {
+		return *rol16_DATA_ptr
+	}
+
+	rol16_DATA := GLOBL("rol16", NOPTR|RODATA)
+	rol16_DATA_ptr = &rol16_DATA
+	DATA(0x00, U64(0x0504070601000302))
+	DATA(0x08, U64(0x0D0C0F0E09080B0A))
+	return rol16_DATA
+}
+
+func rol8_DATA() Mem {
+	if rol8_DATA_ptr != nil {
+		return *rol8_DATA_ptr
+	}
+
+	rol8_DATA := GLOBL("rol8", NOPTR|RODATA)
+	rol8_DATA_ptr = &rol8_DATA
+	DATA(0x00, U64(0x0407060500030201))
+	DATA(0x08, U64(0x0C0F0E0D080B0A09))
+	return rol8_DATA
+}
+
+func counter_DATA() Mem {
+	if counter_DATA_ptr != nil {
+		return *counter_DATA_ptr
+	}
+
+	counter_DATA := GLOBL("counter", NOPTR|RODATA)
+	counter_DATA_ptr = &counter_DATA
+	DATA(0x00, U64(0x0000000000000040))
+	DATA(0x08, U64(0x0000000000000000))
+	return counter_DATA
+}

blake2s/_asm/go.mod

@@ -0,0 +1,15 @@
+module blake2s/_asm
+
+go 1.23
+
+require (
+	github.com/mmcloughlin/avo v0.6.0
+	golang.org/x/crypto v0.33.0
+)
+
+require (
+	golang.org/x/mod v0.20.0 // indirect
+	golang.org/x/sync v0.8.0 // indirect
+	golang.org/x/sys v0.30.0 // indirect
+	golang.org/x/tools v0.24.0 // indirect
+)

blake2s/_asm/go.sum

@@ -0,0 +1,12 @@
+github.com/mmcloughlin/avo v0.6.0 h1:QH6FU8SKoTLaVs80GA8TJuLNkUYl4VokHKlPhVDg4YY=
+github.com/mmcloughlin/avo v0.6.0/go.mod h1:8CoAGaCSYXtCPR+8y18Y9aB/kxb8JSS6FRI7mSkvD+8=
+golang.org/x/crypto v0.33.0 h1:IOBPskki6Lysi0lo9qQvbxiQ+FvsCC/YWOecCHAixus=
+golang.org/x/crypto v0.33.0/go.mod h1:bVdXmD7IV/4GdElGPozy6U7lWdRXA4qyRVGJV57uQ5M=
+golang.org/x/mod v0.20.0 h1:utOm6MM3R3dnawAiJgn0y+xvuYRsm1RKM/4giyfDgV0=
+golang.org/x/mod v0.20.0/go.mod h1:hTbmBsO62+eylJbnUtE2MGJUyE7QWk4xUqPFrRgJ+7c=
+golang.org/x/sync v0.8.0 h1:3NFvSEYkUoMifnESzZl15y791HH1qU2xm6eCJU5ZPXQ=
+golang.org/x/sync v0.8.0/go.mod h1:Czt+wKu1gCyEFDUtn0jG5QVvpJ6rzVqr5aXyt9drQfk=
+golang.org/x/sys v0.30.0 h1:QjkSwP/36a20jFYWkSue1YwXzLmsV5Gfq7Eiy72C1uc=
+golang.org/x/sys v0.30.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
+golang.org/x/tools v0.24.0 h1:J1shsA93PJUEVaUSaay7UXAyE8aimq3GW0pjlolpa24=
+golang.org/x/tools v0.24.0/go.mod h1:YhNqVBIfWHdzvTLs0d8LCuMhkKUgSUKldakyV7W/WDQ=

bn256/gfp12.go

@@ -5,7 +5,7 @@
 package bn256
 
 // For details of the algorithms used, see "Multiplication and Squaring on
-// Pairing-Friendly Fields, Devegili et al.
+// Pairing-Friendly Fields", Devegili et al.
 // http://eprint.iacr.org/2006/471.pdf.
 
 import (

bn256/gfp2.go

@@ -5,7 +5,7 @@
 package bn256
 
 // For details of the algorithms used, see "Multiplication and Squaring on
-// Pairing-Friendly Fields, Devegili et al.
+// Pairing-Friendly Fields", Devegili et al.
 // http://eprint.iacr.org/2006/471.pdf.
 
 import (

bn256/gfp6.go

@@ -5,7 +5,7 @@
 package bn256
 
 // For details of the algorithms used, see "Multiplication and Squaring on
-// Pairing-Friendly Fields, Devegili et al.
+// Pairing-Friendly Fields", Devegili et al.
 // http://eprint.iacr.org/2006/471.pdf.
 
 import (

chacha20/chacha_noasm.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build (!arm64 && !s390x && !ppc64le) || !gc || purego
+//go:build (!arm64 && !s390x && !ppc64 && !ppc64le) || !gc || purego
 
 package chacha20
 

chacha20/chacha_ppc64x.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build gc && !purego
+//go:build gc && !purego && (ppc64 || ppc64le)
 
 package chacha20
 

chacha20/chacha_ppc64x.s

@@ -19,7 +19,7 @@
 // The differences in this and the original implementation are
 // due to the calling conventions and initialization of constants.
 
-//go:build gc && !purego
+//go:build gc && !purego && (ppc64 || ppc64le)
 
 #include "textflag.h"
 
@@ -36,32 +36,68 @@
 // for VPERMXOR
 #define MASK  R18
 
-DATA consts<>+0x00(SB)/8, $0x3320646e61707865
-DATA consts<>+0x08(SB)/8, $0x6b20657479622d32
-DATA consts<>+0x10(SB)/8, $0x0000000000000001
-DATA consts<>+0x18(SB)/8, $0x0000000000000000
-DATA consts<>+0x20(SB)/8, $0x0000000000000004
-DATA consts<>+0x28(SB)/8, $0x0000000000000000
-DATA consts<>+0x30(SB)/8, $0x0a0b08090e0f0c0d
-DATA consts<>+0x38(SB)/8, $0x0203000106070405
-DATA consts<>+0x40(SB)/8, $0x090a0b080d0e0f0c
-DATA consts<>+0x48(SB)/8, $0x0102030005060704
-DATA consts<>+0x50(SB)/8, $0x6170786561707865
-DATA consts<>+0x58(SB)/8, $0x6170786561707865
-DATA consts<>+0x60(SB)/8, $0x3320646e3320646e
-DATA consts<>+0x68(SB)/8, $0x3320646e3320646e
-DATA consts<>+0x70(SB)/8, $0x79622d3279622d32
-DATA consts<>+0x78(SB)/8, $0x79622d3279622d32
-DATA consts<>+0x80(SB)/8, $0x6b2065746b206574
-DATA consts<>+0x88(SB)/8, $0x6b2065746b206574
-DATA consts<>+0x90(SB)/8, $0x0000000100000000
-DATA consts<>+0x98(SB)/8, $0x0000000300000002
-DATA consts<>+0xa0(SB)/8, $0x5566774411223300
-DATA consts<>+0xa8(SB)/8, $0xddeeffcc99aabb88
-DATA consts<>+0xb0(SB)/8, $0x6677445522330011
-DATA consts<>+0xb8(SB)/8, $0xeeffccddaabb8899
+DATA consts<>+0x00(SB)/4, $0x61707865
+DATA consts<>+0x04(SB)/4, $0x3320646e
+DATA consts<>+0x08(SB)/4, $0x79622d32
+DATA consts<>+0x0c(SB)/4, $0x6b206574
+DATA consts<>+0x10(SB)/4, $0x00000001
+DATA consts<>+0x14(SB)/4, $0x00000000
+DATA consts<>+0x18(SB)/4, $0x00000000
+DATA consts<>+0x1c(SB)/4, $0x00000000
+DATA consts<>+0x20(SB)/4, $0x00000004
+DATA consts<>+0x24(SB)/4, $0x00000000
+DATA consts<>+0x28(SB)/4, $0x00000000
+DATA consts<>+0x2c(SB)/4, $0x00000000
+DATA consts<>+0x30(SB)/4, $0x0e0f0c0d
+DATA consts<>+0x34(SB)/4, $0x0a0b0809
+DATA consts<>+0x38(SB)/4, $0x06070405
+DATA consts<>+0x3c(SB)/4, $0x02030001
+DATA consts<>+0x40(SB)/4, $0x0d0e0f0c
+DATA consts<>+0x44(SB)/4, $0x090a0b08
+DATA consts<>+0x48(SB)/4, $0x05060704
+DATA consts<>+0x4c(SB)/4, $0x01020300
+DATA consts<>+0x50(SB)/4, $0x61707865
+DATA consts<>+0x54(SB)/4, $0x61707865
+DATA consts<>+0x58(SB)/4, $0x61707865
+DATA consts<>+0x5c(SB)/4, $0x61707865
+DATA consts<>+0x60(SB)/4, $0x3320646e
+DATA consts<>+0x64(SB)/4, $0x3320646e
+DATA consts<>+0x68(SB)/4, $0x3320646e
+DATA consts<>+0x6c(SB)/4, $0x3320646e
+DATA consts<>+0x70(SB)/4, $0x79622d32
+DATA consts<>+0x74(SB)/4, $0x79622d32
+DATA consts<>+0x78(SB)/4, $0x79622d32
+DATA consts<>+0x7c(SB)/4, $0x79622d32
+DATA consts<>+0x80(SB)/4, $0x6b206574
+DATA consts<>+0x84(SB)/4, $0x6b206574
+DATA consts<>+0x88(SB)/4, $0x6b206574
+DATA consts<>+0x8c(SB)/4, $0x6b206574
+DATA consts<>+0x90(SB)/4, $0x00000000
+DATA consts<>+0x94(SB)/4, $0x00000001
+DATA consts<>+0x98(SB)/4, $0x00000002
+DATA consts<>+0x9c(SB)/4, $0x00000003
+DATA consts<>+0xa0(SB)/4, $0x11223300
+DATA consts<>+0xa4(SB)/4, $0x55667744
+DATA consts<>+0xa8(SB)/4, $0x99aabb88
+DATA consts<>+0xac(SB)/4, $0xddeeffcc
+DATA consts<>+0xb0(SB)/4, $0x22330011
+DATA consts<>+0xb4(SB)/4, $0x66774455
+DATA consts<>+0xb8(SB)/4, $0xaabb8899
+DATA consts<>+0xbc(SB)/4, $0xeeffccdd
 GLOBL consts<>(SB), RODATA, $0xc0
 
+#ifdef GOARCH_ppc64
+#define BE_XXBRW_INIT() \
+		LVSL (R0)(R0), V24 \
+		VSPLTISB $3, V25   \
+		VXOR V24, V25, V24 \
+
+#define BE_XXBRW(vr) VPERM vr, vr, V24, vr
+#else
+#define BE_XXBRW_INIT()
+#define BE_XXBRW(vr)
+#endif
+
 //func chaCha20_ctr32_vsx(out, inp *byte, len int, key *[8]uint32, counter *uint32)
 TEXT ·chaCha20_ctr32_vsx(SB),NOSPLIT,$64-40
 	MOVD out+0(FP), OUT
@@ -94,6 +130,8 @@ TEXT ·chaCha20_ctr32_vsx(SB),NOSPLIT,$64-40
 	// Clear V27
 	VXOR V27, V27, V27
 
+	BE_XXBRW_INIT()
+
 	// V28
 	LXVW4X (CONSTBASE)(R11), VS60
 
@@ -299,6 +337,11 @@ loop_vsx:
 	VADDUWM V8, V18, V8
 	VADDUWM V12, V19, V12
 
+	BE_XXBRW(V0)
+	BE_XXBRW(V4)
+	BE_XXBRW(V8)
+	BE_XXBRW(V12)
+
 	CMPU LEN, $64
 	BLT tail_vsx
 
@@ -327,6 +370,11 @@ loop_vsx:
 	VADDUWM V9, V18, V8
 	VADDUWM V13, V19, V12
 
+	BE_XXBRW(V0)
+	BE_XXBRW(V4)
+	BE_XXBRW(V8)
+	BE_XXBRW(V12)
+
 	CMPU  LEN, $64
 	BLT   tail_vsx
 
@@ -334,8 +382,8 @@ loop_vsx:
 	LXVW4X (INP)(R8), VS60
 	LXVW4X (INP)(R9), VS61
 	LXVW4X (INP)(R10), VS62
-	VXOR   V27, V0, V27
 
+	VXOR V27, V0, V27
 	VXOR V28, V4, V28
 	VXOR V29, V8, V29
 	VXOR V30, V12, V30
@@ -354,6 +402,11 @@ loop_vsx:
 	VADDUWM V10, V18, V8
 	VADDUWM V14, V19, V12
 
+	BE_XXBRW(V0)
+	BE_XXBRW(V4)
+	BE_XXBRW(V8)
+	BE_XXBRW(V12)
+
 	CMPU LEN, $64
 	BLT  tail_vsx
 
@@ -381,6 +434,11 @@ loop_vsx:
 	VADDUWM V11, V18, V8
 	VADDUWM V15, V19, V12
 
+	BE_XXBRW(V0)
+	BE_XXBRW(V4)
+	BE_XXBRW(V8)
+	BE_XXBRW(V12)
+
 	CMPU  LEN, $64
 	BLT   tail_vsx
 
@@ -408,9 +466,9 @@ loop_vsx:
 
 done_vsx:
 	// Increment counter by number of 64 byte blocks
-	MOVD (CNT), R14
+	MOVWZ (CNT), R14
 	ADD  BLOCKS, R14
-	MOVD R14, (CNT)
+	MOVWZ R14, (CNT)
 	RET
 
 tail_vsx:

chacha20poly1305/_asm/go.mod

@@ -0,0 +1,15 @@
+module chacha20poly1305/_asm
+
+go 1.23
+
+require (
+	github.com/mmcloughlin/avo v0.6.0
+	golang.org/x/crypto v0.33.0
+)
+
+require (
+	golang.org/x/mod v0.20.0 // indirect
+	golang.org/x/sync v0.8.0 // indirect
+	golang.org/x/sys v0.30.0 // indirect
+	golang.org/x/tools v0.24.0 // indirect
+)

chacha20poly1305/_asm/go.sum

@@ -0,0 +1,12 @@
+github.com/mmcloughlin/avo v0.6.0 h1:QH6FU8SKoTLaVs80GA8TJuLNkUYl4VokHKlPhVDg4YY=
+github.com/mmcloughlin/avo v0.6.0/go.mod h1:8CoAGaCSYXtCPR+8y18Y9aB/kxb8JSS6FRI7mSkvD+8=
+golang.org/x/crypto v0.33.0 h1:IOBPskki6Lysi0lo9qQvbxiQ+FvsCC/YWOecCHAixus=
+golang.org/x/crypto v0.33.0/go.mod h1:bVdXmD7IV/4GdElGPozy6U7lWdRXA4qyRVGJV57uQ5M=
+golang.org/x/mod v0.20.0 h1:utOm6MM3R3dnawAiJgn0y+xvuYRsm1RKM/4giyfDgV0=
+golang.org/x/mod v0.20.0/go.mod h1:hTbmBsO62+eylJbnUtE2MGJUyE7QWk4xUqPFrRgJ+7c=
+golang.org/x/sync v0.8.0 h1:3NFvSEYkUoMifnESzZl15y791HH1qU2xm6eCJU5ZPXQ=
+golang.org/x/sync v0.8.0/go.mod h1:Czt+wKu1gCyEFDUtn0jG5QVvpJ6rzVqr5aXyt9drQfk=
+golang.org/x/sys v0.30.0 h1:QjkSwP/36a20jFYWkSue1YwXzLmsV5Gfq7Eiy72C1uc=
+golang.org/x/sys v0.30.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
+golang.org/x/tools v0.24.0 h1:J1shsA93PJUEVaUSaay7UXAyE8aimq3GW0pjlolpa24=
+golang.org/x/tools v0.24.0/go.mod h1:YhNqVBIfWHdzvTLs0d8LCuMhkKUgSUKldakyV7W/WDQ=

cryptobyte/asn1.go

@@ -234,7 +234,7 @@ func (b *Builder) AddASN1(tag asn1.Tag, f BuilderContinuation) {
 	// Identifiers with the low five bits set indicate high-tag-number format
 	// (two or more octets), which we don't support.
 	if tag&0x1f == 0x1f {
-		b.err = fmt.Errorf("cryptobyte: high-tag number identifier octects not supported: 0x%x", tag)
+		b.err = fmt.Errorf("cryptobyte: high-tag number identifier octets not supported: 0x%x", tag)
 		return
 	}
 	b.AddUint8(uint8(tag))

curve25519/curve25519.go

@@ -36,7 +36,7 @@ func ScalarBaseMult(dst, scalar *[32]byte) {
 	curve := ecdh.X25519()
 	priv, err := curve.NewPrivateKey(scalar[:])
 	if err != nil {
-		panic("curve25519: internal error: scalarBaseMult was not 32 bytes")
+		panic("curve25519: " + err.Error())
 	}
 	copy(dst[:], priv.PublicKey().Bytes())
 }

go.mod

@@ -1,11 +1,11 @@
 module golang.org/x/crypto
 
-go 1.20
+go 1.24.0
 
 require (
-	golang.org/x/net v0.21.0 // tagx:ignore
-	golang.org/x/sys v0.23.0
-	golang.org/x/term v0.23.0
+	golang.org/x/net v0.43.0 // tagx:ignore
+	golang.org/x/sys v0.36.0
+	golang.org/x/term v0.35.0
 )
 
-require golang.org/x/text v0.17.0 // indirect
+require golang.org/x/text v0.29.0 // indirect

go.sum

@@ -1,8 +1,8 @@
-golang.org/x/net v0.21.0 h1:AQyQV4dYCvJ7vGmJyKki9+PBdyvhkSd8EIx/qb0AYv4=
-golang.org/x/net v0.21.0/go.mod h1:bIjVDfnllIU7BJ2DNgfnXvpSvtn8VRwhlsaeUTyUS44=
-golang.org/x/sys v0.23.0 h1:YfKFowiIMvtgl1UERQoTPPToxltDeZfbj4H7dVUCwmM=
-golang.org/x/sys v0.23.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
-golang.org/x/term v0.23.0 h1:F6D4vR+EHoL9/sWAWgAR1H2DcHr4PareCbAaCo1RpuU=
-golang.org/x/term v0.23.0/go.mod h1:DgV24QBUrK6jhZXl+20l6UWznPlwAHm1Q1mGHtydmSk=
-golang.org/x/text v0.17.0 h1:XtiM5bkSOt+ewxlOE/aE/AKEHibwj/6gvWMl9Rsh0Qc=
-golang.org/x/text v0.17.0/go.mod h1:BuEKDfySbSR4drPmRPG/7iBdf8hvFMuRexcpahXilzY=
+golang.org/x/net v0.43.0 h1:lat02VYK2j4aLzMzecihNvTlJNQUq316m2Mr9rnM6YE=
+golang.org/x/net v0.43.0/go.mod h1:vhO1fvI4dGsIjh73sWfUVjj3N7CA9WkKJNQm2svM6Jg=
+golang.org/x/sys v0.36.0 h1:KVRy2GtZBrk1cBYA7MKu5bEZFxQk4NIDV6RLVcC8o0k=
+golang.org/x/sys v0.36.0/go.mod h1:OgkHotnGiDImocRcuBABYBEXf8A9a87e/uXjp9XT3ks=
+golang.org/x/term v0.35.0 h1:bZBVKBudEyhRcajGcNc3jIfWPqV4y/Kt2XcoigOWtDQ=
+golang.org/x/term v0.35.0/go.mod h1:TPGtkTLesOwf2DE8CgVYiZinHAOuy5AYUYT1lENIZnA=
+golang.org/x/text v0.29.0 h1:1neNs90w9YzJ9BocxfsQNHKuAT4pkghyXc4nhZ6sJvk=
+golang.org/x/text v0.29.0/go.mod h1:7MhJOA9CD2qZyOKYazxdYMF85OwPdEr9jTtBpO7ydH4=

internal/poly1305/_asm/go.mod

@@ -0,0 +1,15 @@
+module internal/poly1305/_asm
+
+go 1.23
+
+require (
+	github.com/mmcloughlin/avo v0.6.0
+	golang.org/x/crypto v0.33.0
+)
+
+require (
+	golang.org/x/mod v0.20.0 // indirect
+	golang.org/x/sync v0.8.0 // indirect
+	golang.org/x/sys v0.30.0 // indirect
+	golang.org/x/tools v0.24.0 // indirect
+)

internal/poly1305/_asm/go.sum

@@ -0,0 +1,12 @@
+github.com/mmcloughlin/avo v0.6.0 h1:QH6FU8SKoTLaVs80GA8TJuLNkUYl4VokHKlPhVDg4YY=
+github.com/mmcloughlin/avo v0.6.0/go.mod h1:8CoAGaCSYXtCPR+8y18Y9aB/kxb8JSS6FRI7mSkvD+8=
+golang.org/x/crypto v0.33.0 h1:IOBPskki6Lysi0lo9qQvbxiQ+FvsCC/YWOecCHAixus=
+golang.org/x/crypto v0.33.0/go.mod h1:bVdXmD7IV/4GdElGPozy6U7lWdRXA4qyRVGJV57uQ5M=
+golang.org/x/mod v0.20.0 h1:utOm6MM3R3dnawAiJgn0y+xvuYRsm1RKM/4giyfDgV0=
+golang.org/x/mod v0.20.0/go.mod h1:hTbmBsO62+eylJbnUtE2MGJUyE7QWk4xUqPFrRgJ+7c=
+golang.org/x/sync v0.8.0 h1:3NFvSEYkUoMifnESzZl15y791HH1qU2xm6eCJU5ZPXQ=
+golang.org/x/sync v0.8.0/go.mod h1:Czt+wKu1gCyEFDUtn0jG5QVvpJ6rzVqr5aXyt9drQfk=
+golang.org/x/sys v0.30.0 h1:QjkSwP/36a20jFYWkSue1YwXzLmsV5Gfq7Eiy72C1uc=
+golang.org/x/sys v0.30.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
+golang.org/x/tools v0.24.0 h1:J1shsA93PJUEVaUSaay7UXAyE8aimq3GW0pjlolpa24=
+golang.org/x/tools v0.24.0/go.mod h1:YhNqVBIfWHdzvTLs0d8LCuMhkKUgSUKldakyV7W/WDQ=

internal/poly1305/_asm/sum_amd64_asm.go

@@ -0,0 +1,126 @@
+// Copyright 2024 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package main
+
+import (
+	. "github.com/mmcloughlin/avo/build"
+	. "github.com/mmcloughlin/avo/operand"
+	. "github.com/mmcloughlin/avo/reg"
+	_ "golang.org/x/crypto/sha3"
+)
+
+//go:generate go run . -out ../sum_amd64.s -pkg poly1305
+
+func main() {
+	Package("golang.org/x/crypto/internal/poly1305")
+	ConstraintExpr("gc,!purego")
+	update()
+	Generate()
+}
+
+func update() {
+	Implement("update")
+
+	Load(Param("state"), RDI)
+	MOVQ(NewParamAddr("msg_base", 8), RSI)
+	MOVQ(NewParamAddr("msg_len", 16), R15)
+
+	MOVQ(Mem{Base: DI}.Offset(0), R8)   // h0
+	MOVQ(Mem{Base: DI}.Offset(8), R9)   // h1
+	MOVQ(Mem{Base: DI}.Offset(16), R10) // h2
+	MOVQ(Mem{Base: DI}.Offset(24), R11) // r0
+	MOVQ(Mem{Base: DI}.Offset(32), R12) // r1
+
+	CMPQ(R15, Imm(16))
+	JB(LabelRef("bytes_between_0_and_15"))
+
+	Label("loop")
+	POLY1305_ADD(RSI, R8, R9, R10)
+
+	Label("multiply")
+	POLY1305_MUL(R8, R9, R10, R11, R12, RBX, RCX, R13, R14)
+	SUBQ(Imm(16), R15)
+	CMPQ(R15, Imm(16))
+	JAE(LabelRef("loop"))
+
+	Label("bytes_between_0_and_15")
+	TESTQ(R15, R15)
+	JZ(LabelRef("done"))
+	MOVQ(U32(1), RBX)
+	XORQ(RCX, RCX)
+	XORQ(R13, R13)
+	ADDQ(R15, RSI)
+
+	Label("flush_buffer")
+	SHLQ(Imm(8), RBX, RCX)
+	SHLQ(Imm(8), RBX)
+	MOVB(Mem{Base: SI}.Offset(-1), R13B)
+	XORQ(R13, RBX)
+	DECQ(RSI)
+	DECQ(R15)
+	JNZ(LabelRef("flush_buffer"))
+
+	ADDQ(RBX, R8)
+	ADCQ(RCX, R9)
+	ADCQ(Imm(0), R10)
+	MOVQ(U32(16), R15)
+	JMP(LabelRef("multiply"))
+
+	Label("done")
+	MOVQ(R8, Mem{Base: DI}.Offset(0))
+	MOVQ(R9, Mem{Base: DI}.Offset(8))
+	MOVQ(R10, Mem{Base: DI}.Offset(16))
+	RET()
+}
+
+func POLY1305_ADD(msg, h0, h1, h2 GPPhysical) {
+	ADDQ(Mem{Base: msg}.Offset(0), h0)
+	ADCQ(Mem{Base: msg}.Offset(8), h1)
+	ADCQ(Imm(1), h2)
+	LEAQ(Mem{Base: msg}.Offset(16), msg)
+}
+
+func POLY1305_MUL(h0, h1, h2, r0, r1, t0, t1, t2, t3 GPPhysical) {
+	MOVQ(r0, RAX)
+	MULQ(h0)
+	MOVQ(RAX, t0)
+	MOVQ(RDX, t1)
+	MOVQ(r0, RAX)
+	MULQ(h1)
+	ADDQ(RAX, t1)
+	ADCQ(Imm(0), RDX)
+	MOVQ(r0, t2)
+	IMULQ(h2, t2)
+	ADDQ(RDX, t2)
+
+	MOVQ(r1, RAX)
+	MULQ(h0)
+	ADDQ(RAX, t1)
+	ADCQ(Imm(0), RDX)
+	MOVQ(RDX, h0)
+	MOVQ(r1, t3)
+	IMULQ(h2, t3)
+	MOVQ(r1, RAX)
+	MULQ(h1)
+	ADDQ(RAX, t2)
+	ADCQ(RDX, t3)
+	ADDQ(h0, t2)
+	ADCQ(Imm(0), t3)
+
+	MOVQ(t0, h0)
+	MOVQ(t1, h1)
+	MOVQ(t2, h2)
+	ANDQ(Imm(3), h2)
+	MOVQ(t2, t0)
+	ANDQ(I32(-4), t0)
+	ADDQ(t0, h0)
+	ADCQ(t3, h1)
+	ADCQ(Imm(0), h2)
+	SHRQ(Imm(2), t3, t2)
+	SHRQ(Imm(2), t3)
+	ADDQ(t2, h0)
+	ADCQ(t3, h1)
+	ADCQ(Imm(0), h2)
+}

internal/poly1305/mac_noasm.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build (!amd64 && !ppc64le && !s390x) || !gc || purego
+//go:build (!amd64 && !loong64 && !ppc64le && !ppc64 && !s390x) || !gc || purego
 
 package poly1305
 

internal/poly1305/sum_amd64.s

@@ -1,108 +1,93 @@
-// Copyright 2012 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
+// Code generated by command: go run sum_amd64_asm.go -out ../sum_amd64.s -pkg poly1305. DO NOT EDIT.
 
 //go:build gc && !purego
 
-#include "textflag.h"
-
-#define POLY1305_ADD(msg, h0, h1, h2) \
-	ADDQ 0(msg), h0;  \
-	ADCQ 8(msg), h1;  \
-	ADCQ $1, h2;      \
-	LEAQ 16(msg), msg
-
-#define POLY1305_MUL(h0, h1, h2, r0, r1, t0, t1, t2, t3) \
-	MOVQ  r0, AX;                  \
-	MULQ  h0;                      \
-	MOVQ  AX, t0;                  \
-	MOVQ  DX, t1;                  \
-	MOVQ  r0, AX;                  \
-	MULQ  h1;                      \
-	ADDQ  AX, t1;                  \
-	ADCQ  $0, DX;                  \
-	MOVQ  r0, t2;                  \
-	IMULQ h2, t2;                  \
-	ADDQ  DX, t2;                  \
-	                               \
-	MOVQ  r1, AX;                  \
-	MULQ  h0;                      \
-	ADDQ  AX, t1;                  \
-	ADCQ  $0, DX;                  \
-	MOVQ  DX, h0;                  \
-	MOVQ  r1, t3;                  \
-	IMULQ h2, t3;                  \
-	MOVQ  r1, AX;                  \
-	MULQ  h1;                      \
-	ADDQ  AX, t2;                  \
-	ADCQ  DX, t3;                  \
-	ADDQ  h0, t2;                  \
-	ADCQ  $0, t3;                  \
-	                               \
-	MOVQ  t0, h0;                  \
-	MOVQ  t1, h1;                  \
-	MOVQ  t2, h2;                  \
-	ANDQ  $3, h2;                  \
-	MOVQ  t2, t0;                  \
-	ANDQ  $0xFFFFFFFFFFFFFFFC, t0; \
-	ADDQ  t0, h0;                  \
-	ADCQ  t3, h1;                  \
-	ADCQ  $0, h2;                  \
-	SHRQ  $2, t3, t2;              \
-	SHRQ  $2, t3;                  \
-	ADDQ  t2, h0;                  \
-	ADCQ  t3, h1;                  \
-	ADCQ  $0, h2
-
-// func update(state *[7]uint64, msg []byte)
+// func update(state *macState, msg []byte)
 TEXT ·update(SB), $0-32
 	MOVQ state+0(FP), DI
 	MOVQ msg_base+8(FP), SI
 	MOVQ msg_len+16(FP), R15
-
-	MOVQ 0(DI), R8   // h0
-	MOVQ 8(DI), R9   // h1
-	MOVQ 16(DI), R10 // h2
-	MOVQ 24(DI), R11 // r0
-	MOVQ 32(DI), R12 // r1
-
-	CMPQ R15, $16
+	MOVQ (DI), R8
+	MOVQ 8(DI), R9
+	MOVQ 16(DI), R10
+	MOVQ 24(DI), R11
+	MOVQ 32(DI), R12
+	CMPQ R15, $0x10
 	JB   bytes_between_0_and_15
 
 loop:
-	POLY1305_ADD(SI, R8, R9, R10)
+	ADDQ (SI), R8
+	ADCQ 8(SI), R9
+	ADCQ $0x01, R10
+	LEAQ 16(SI), SI
 
 multiply:
-	POLY1305_MUL(R8, R9, R10, R11, R12, BX, CX, R13, R14)
-	SUBQ $16, R15
-	CMPQ R15, $16
-	JAE  loop
+	MOVQ  R11, AX
+	MULQ  R8
+	MOVQ  AX, BX
+	MOVQ  DX, CX
+	MOVQ  R11, AX
+	MULQ  R9
+	ADDQ  AX, CX
+	ADCQ  $0x00, DX
+	MOVQ  R11, R13
+	IMULQ R10, R13
+	ADDQ  DX, R13
+	MOVQ  R12, AX
+	MULQ  R8
+	ADDQ  AX, CX
+	ADCQ  $0x00, DX
+	MOVQ  DX, R8
+	MOVQ  R12, R14
+	IMULQ R10, R14
+	MOVQ  R12, AX
+	MULQ  R9
+	ADDQ  AX, R13
+	ADCQ  DX, R14
+	ADDQ  R8, R13
+	ADCQ  $0x00, R14
+	MOVQ  BX, R8
+	MOVQ  CX, R9
+	MOVQ  R13, R10
+	ANDQ  $0x03, R10
+	MOVQ  R13, BX
+	ANDQ  $-4, BX
+	ADDQ  BX, R8
+	ADCQ  R14, R9
+	ADCQ  $0x00, R10
+	SHRQ  $0x02, R14, R13
+	SHRQ  $0x02, R14
+	ADDQ  R13, R8
+	ADCQ  R14, R9
+	ADCQ  $0x00, R10
+	SUBQ  $0x10, R15
+	CMPQ  R15, $0x10
+	JAE   loop
 
 bytes_between_0_and_15:
 	TESTQ R15, R15
 	JZ    done
-	MOVQ  $1, BX
+	MOVQ  $0x00000001, BX
 	XORQ  CX, CX
 	XORQ  R13, R13
 	ADDQ  R15, SI
 
 flush_buffer:
-	SHLQ $8, BX, CX
-	SHLQ $8, BX
+	SHLQ $0x08, BX, CX
+	SHLQ $0x08, BX
 	MOVB -1(SI), R13
 	XORQ R13, BX
 	DECQ SI
 	DECQ R15
 	JNZ  flush_buffer
-
 	ADDQ BX, R8
 	ADCQ CX, R9
-	ADCQ $0, R10
-	MOVQ $16, R15
+	ADCQ $0x00, R10
+	MOVQ $0x00000010, R15
 	JMP  multiply
 
 done:
-	MOVQ R8, 0(DI)
+	MOVQ R8, (DI)
 	MOVQ R9, 8(DI)
 	MOVQ R10, 16(DI)
 	RET

internal/poly1305/sum_asm.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build gc && !purego
+//go:build gc && !purego && (amd64 || loong64 || ppc64 || ppc64le)
 
 package poly1305
 

internal/poly1305/sum_loong64.s

@@ -0,0 +1,123 @@
+// Copyright 2025 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build gc && !purego
+
+// func update(state *macState, msg []byte)
+TEXT ·update(SB), $0-32
+	MOVV	state+0(FP), R4
+	MOVV	msg_base+8(FP), R5
+	MOVV	msg_len+16(FP), R6
+
+	MOVV	$0x10, R7
+
+	MOVV	(R4), R8	// h0
+	MOVV	8(R4), R9	// h1
+	MOVV	16(R4), R10	// h2
+	MOVV	24(R4), R11	// r0
+	MOVV	32(R4), R12	// r1
+
+	BLT	R6, R7, bytes_between_0_and_15
+
+loop:
+	MOVV	(R5), R14	// msg[0:8]
+	MOVV	8(R5), R16	// msg[8:16]
+	ADDV	R14, R8, R8	// h0 (x1 + y1 = z1', if z1' < x1 then z1' overflow)
+	ADDV	R16, R9, R27
+	SGTU	R14, R8, R24	// h0.carry
+	SGTU	R9, R27, R28
+	ADDV	R27, R24, R9	// h1
+	SGTU	R27, R9, R24
+	OR	R24, R28, R24	// h1.carry
+	ADDV	$0x01, R24, R24
+	ADDV	R10, R24, R10	// h2
+
+	ADDV	$16, R5, R5	// msg = msg[16:]
+
+multiply:
+	MULV	R8, R11, R14	// h0r0.lo
+	MULHVU	R8, R11, R15	// h0r0.hi
+	MULV	R9, R11, R13	// h1r0.lo
+	MULHVU	R9, R11, R16	// h1r0.hi
+	ADDV	R13, R15, R15
+	SGTU	R13, R15, R24
+	ADDV	R24, R16, R16
+	MULV	R10, R11, R25
+	ADDV	R16, R25, R25
+	MULV	R8, R12, R13	// h0r1.lo
+	MULHVU	R8, R12, R16	// h0r1.hi
+	ADDV	R13, R15, R15
+	SGTU	R13, R15, R24
+	ADDV	R24, R16, R16
+	MOVV	R16, R8
+	MULV	R10, R12, R26	// h2r1
+	MULV	R9, R12, R13	// h1r1.lo
+	MULHVU	R9, R12, R16	// h1r1.hi
+	ADDV	R13, R25, R25
+	ADDV	R16, R26, R27
+	SGTU	R13, R25, R24
+	ADDV	R27, R24, R26
+	ADDV	R8, R25, R25
+	SGTU	R8, R25, R24
+	ADDV	R24, R26, R26
+	AND	$3, R25, R10
+	AND	$-4, R25, R17
+	ADDV	R17, R14, R8
+	ADDV	R26, R15, R27
+	SGTU	R17, R8, R24
+	SGTU	R26, R27, R28
+	ADDV	R27, R24, R9
+	SGTU	R27, R9, R24
+	OR	R24, R28, R24
+	ADDV	R24, R10, R10
+	SLLV	$62, R26, R27
+	SRLV	$2, R25, R28
+	SRLV	$2, R26, R26
+	OR	R27, R28, R25
+	ADDV	R25, R8, R8
+	ADDV	R26, R9, R27
+	SGTU	R25, R8, R24
+	SGTU	R26, R27, R28
+	ADDV	R27, R24, R9
+	SGTU	R27, R9, R24
+	OR	R24, R28, R24
+	ADDV	R24, R10, R10
+
+	SUBV	$16, R6, R6
+	BGE	R6, R7, loop
+
+bytes_between_0_and_15:
+	BEQ	R6, R0, done
+	MOVV	$1, R14
+	XOR	R15, R15
+	ADDV	R6, R5, R5
+
+flush_buffer:
+	MOVBU	-1(R5), R25
+	SRLV	$56, R14, R24
+	SLLV	$8, R15, R28
+	SLLV	$8, R14, R14
+	OR	R24, R28, R15
+	XOR	R25, R14, R14
+	SUBV	$1, R6, R6
+	SUBV	$1, R5, R5
+	BNE	R6, R0, flush_buffer
+
+	ADDV	R14, R8, R8
+	SGTU	R14, R8, R24
+	ADDV	R15, R9, R27
+	SGTU	R15, R27, R28
+	ADDV	R27, R24, R9
+	SGTU	R27, R9, R24
+	OR	R24, R28, R24
+	ADDV	R10, R24, R10
+
+	MOVV	$16, R6
+	JMP	multiply
+
+done:
+	MOVV	R8, (R4)
+	MOVV	R9, 8(R4)
+	MOVV	R10, 16(R4)
+	RET

internal/poly1305/sum_ppc64le.go

@@ -1,47 +0,0 @@
-// Copyright 2019 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-//go:build gc && !purego
-
-package poly1305
-
-//go:noescape
-func update(state *macState, msg []byte)
-
-// mac is a wrapper for macGeneric that redirects calls that would have gone to
-// updateGeneric to update.
-//
-// Its Write and Sum methods are otherwise identical to the macGeneric ones, but
-// using function pointers would carry a major performance cost.
-type mac struct{ macGeneric }
-
-func (h *mac) Write(p []byte) (int, error) {
-	nn := len(p)
-	if h.offset > 0 {
-		n := copy(h.buffer[h.offset:], p)
-		if h.offset+n < TagSize {
-			h.offset += n
-			return nn, nil
-		}
-		p = p[n:]
-		h.offset = 0
-		update(&h.macState, h.buffer[:])
-	}
-	if n := len(p) - (len(p) % TagSize); n > 0 {
-		update(&h.macState, p[:n])
-		p = p[n:]
-	}
-	if len(p) > 0 {
-		h.offset += copy(h.buffer[h.offset:], p)
-	}
-	return nn, nil
-}
-
-func (h *mac) Sum(out *[16]byte) {
-	state := h.macState
-	if h.offset > 0 {
-		update(&state, h.buffer[:h.offset])
-	}
-	finalize(out, &state.h, &state.s)
-}

internal/poly1305/sum_ppc64x.s

@@ -2,15 +2,25 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build gc && !purego
+//go:build gc && !purego && (ppc64 || ppc64le)
 
 #include "textflag.h"
 
 // This was ported from the amd64 implementation.
 
+#ifdef GOARCH_ppc64le
+#define LE_MOVD MOVD
+#define LE_MOVWZ MOVWZ
+#define LE_MOVHZ MOVHZ
+#else
+#define LE_MOVD MOVDBR
+#define LE_MOVWZ MOVWBR
+#define LE_MOVHZ MOVHBR
+#endif
+
 #define POLY1305_ADD(msg, h0, h1, h2, t0, t1, t2) \
-	MOVD (msg), t0;  \
-	MOVD 8(msg), t1; \
+	LE_MOVD (msg)( R0), t0; \
+	LE_MOVD (msg)(R24), t1; \
 	MOVD $1, t2;     \
 	ADDC t0, h0, h0; \
 	ADDE t1, h1, h1; \
@@ -50,10 +60,6 @@
 	ADDE   t3, h1, h1;  \
 	ADDZE  h2
 
-DATA ·poly1305Mask<>+0x00(SB)/8, $0x0FFFFFFC0FFFFFFF
-DATA ·poly1305Mask<>+0x08(SB)/8, $0x0FFFFFFC0FFFFFFC
-GLOBL ·poly1305Mask<>(SB), RODATA, $16
-
 // func update(state *[7]uint64, msg []byte)
 TEXT ·update(SB), $0-32
 	MOVD state+0(FP), R3
@@ -66,6 +72,8 @@ TEXT ·update(SB), $0-32
 	MOVD 24(R3), R11 // r0
 	MOVD 32(R3), R12 // r1
 
+	MOVD $8, R24
+
 	CMP R5, $16
 	BLT bytes_between_0_and_15
 
@@ -94,7 +102,7 @@ flush_buffer:
 
 	// Greater than 8 -- load the rightmost remaining bytes in msg
 	// and put into R17 (h1)
-	MOVD (R4)(R21), R17
+	LE_MOVD (R4)(R21), R17
 	MOVD $16, R22
 
 	// Find the offset to those bytes
@@ -118,7 +126,7 @@ just1:
 	BLT less8
 
 	// Exactly 8
-	MOVD (R4), R16
+	LE_MOVD (R4), R16
 
 	CMP R17, $0
 
@@ -133,7 +141,7 @@ less8:
 	MOVD  $0, R22   // shift count
 	CMP   R5, $4
 	BLT   less4
-	MOVWZ (R4), R16
+	LE_MOVWZ (R4), R16
 	ADD   $4, R4
 	ADD   $-4, R5
 	MOVD  $32, R22
@@ -141,7 +149,7 @@ less8:
 less4:
 	CMP   R5, $2
 	BLT   less2
-	MOVHZ (R4), R21
+	LE_MOVHZ (R4), R21
 	SLD   R22, R21, R21
 	OR    R16, R21, R16
 	ADD   $16, R22

openpgp/clearsign/clearsign_test.go

@@ -123,24 +123,12 @@ func TestSigning(t *testing.T) {
 	}
 }
 
-// We use this to make test keys, so that they aren't all the same.
-type quickRand byte
-
-func (qr *quickRand) Read(p []byte) (int, error) {
-	for i := range p {
-		p[i] = byte(*qr)
-	}
-	*qr++
-	return len(p), nil
-}
-
 func TestMultiSign(t *testing.T) {
 	if testing.Short() {
 		t.Skip("skipping long test in -short mode")
 	}
 
-	zero := quickRand(0)
-	config := packet.Config{Rand: &zero}
+	var config packet.Config
 
 	for nKeys := 0; nKeys < 4; nKeys++ {
 	nextTest:

pkcs12/crypto.go

@@ -26,7 +26,7 @@ type pbeCipher interface {
 	create(key []byte) (cipher.Block, error)
 	// deriveKey returns a key derived from the given password and salt.
 	deriveKey(salt, password []byte, iterations int) []byte
-	// deriveKey returns an IV derived from the given password and salt.
+	// deriveIV returns an IV derived from the given password and salt.
 	deriveIV(salt, password []byte, iterations int) []byte
 }
 

salsa20/salsa/_asm/go.mod

@@ -0,0 +1,14 @@
+module salsa20/salsa/_asm
+
+go 1.23
+
+require (
+	github.com/mmcloughlin/avo v0.6.0
+	golang.org/x/crypto v0.33.0
+)
+
+require (
+	golang.org/x/mod v0.20.0 // indirect
+	golang.org/x/sync v0.8.0 // indirect
+	golang.org/x/tools v0.24.0 // indirect
+)

salsa20/salsa/_asm/go.sum

@@ -0,0 +1,10 @@
+github.com/mmcloughlin/avo v0.6.0 h1:QH6FU8SKoTLaVs80GA8TJuLNkUYl4VokHKlPhVDg4YY=
+github.com/mmcloughlin/avo v0.6.0/go.mod h1:8CoAGaCSYXtCPR+8y18Y9aB/kxb8JSS6FRI7mSkvD+8=
+golang.org/x/crypto v0.33.0 h1:IOBPskki6Lysi0lo9qQvbxiQ+FvsCC/YWOecCHAixus=
+golang.org/x/crypto v0.33.0/go.mod h1:bVdXmD7IV/4GdElGPozy6U7lWdRXA4qyRVGJV57uQ5M=
+golang.org/x/mod v0.20.0 h1:utOm6MM3R3dnawAiJgn0y+xvuYRsm1RKM/4giyfDgV0=
+golang.org/x/mod v0.20.0/go.mod h1:hTbmBsO62+eylJbnUtE2MGJUyE7QWk4xUqPFrRgJ+7c=
+golang.org/x/sync v0.8.0 h1:3NFvSEYkUoMifnESzZl15y791HH1qU2xm6eCJU5ZPXQ=
+golang.org/x/sync v0.8.0/go.mod h1:Czt+wKu1gCyEFDUtn0jG5QVvpJ6rzVqr5aXyt9drQfk=
+golang.org/x/tools v0.24.0 h1:J1shsA93PJUEVaUSaay7UXAyE8aimq3GW0pjlolpa24=
+golang.org/x/tools v0.24.0/go.mod h1:YhNqVBIfWHdzvTLs0d8LCuMhkKUgSUKldakyV7W/WDQ=

salsa20/salsa/_asm/salsa20_amd64_asm.go

@@ -0,0 +1,932 @@
+// Copyright 2024 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// This code was translated into a form compatible with 6a from the public
+// domain sources in SUPERCOP: https://bench.cr.yp.to/supercop.html
+
+package main
+
+import (
+	. "github.com/mmcloughlin/avo/build"
+	"github.com/mmcloughlin/avo/ir"
+	. "github.com/mmcloughlin/avo/operand"
+	. "github.com/mmcloughlin/avo/reg"
+	_ "golang.org/x/crypto/salsa20/salsa"
+)
+
+//go:generate go run . -out ../salsa20_amd64.s -pkg salsa
+
+func main() {
+	Package("golang.org/x/crypto/salsa20/salsa")
+	ConstraintExpr("amd64,!purego,gc")
+	salsa2020XORKeyStream()
+	Generate()
+}
+
+func salsa2020XORKeyStream() {
+	Implement("salsa2020XORKeyStream")
+	Attributes(0)
+	AllocLocal(456) // frame = 424 + 32 byte alignment
+	Comment("This needs up to 64 bytes at 360(R12); hence the non-obvious frame size.")
+
+	Load(Param("out"), RDI)
+	Load(Param("in"), RSI)
+	Load(Param("n"), RDX)
+	Load(Param("nonce"), RCX)
+	Load(Param("key"), R8)
+
+	MOVQ(RSP, R12)
+	ADDQ(Imm(31), R12)
+	ANDQ(I32(^31), R12)
+
+	MOVQ(RDX, R9)
+	MOVQ(RCX, RDX)
+	MOVQ(R8, R10)
+	CMPQ(R9, Imm(0))
+	JBE(LabelRef("DONE"))
+
+	START()
+	BYTESATLEAST256()
+	MAINLOOP1()
+	BYTESBETWEEN1AND255()
+	NOCOPY()
+	MAINLOOP2()
+
+	Label("BYTESATLEAST64")
+	Label("DONE")
+	RET()
+	Label("BYTESATLEAST65")
+	SUBQ(Imm(64), R9)
+	ADDQ(Imm(64), RDI)
+	ADDQ(Imm(64), RSI)
+	JMP(LabelRef("BYTESBETWEEN1AND255"))
+}
+
+func START() {
+	Label("START")
+	MOVL(Mem{Base: R10}.Offset(20), ECX)
+	MOVL(Mem{Base: R10}.Offset(0), R8L)
+	MOVL(Mem{Base: EDX}.Offset(0), EAX)
+	MOVL(Mem{Base: R10}.Offset(16), R11L)
+	MOVL(ECX, Mem{Base: R12}.Offset(0))
+	MOVL(R8L, Mem{Base: R12}.Offset(4))
+	MOVL(EAX, Mem{Base: R12}.Offset(8))
+	MOVL(R11L, Mem{Base: R12}.Offset(12))
+	MOVL(Mem{Base: EDX}.Offset(8), ECX)
+	MOVL(Mem{Base: R10}.Offset(24), R8L)
+	MOVL(Mem{Base: R10}.Offset(4), EAX)
+	MOVL(Mem{Base: EDX}.Offset(4), R11L)
+	MOVL(ECX, Mem{Base: R12}.Offset(16))
+	MOVL(R8L, Mem{Base: R12}.Offset(20))
+	MOVL(EAX, Mem{Base: R12}.Offset(24))
+	MOVL(R11L, Mem{Base: R12}.Offset(28))
+	MOVL(Mem{Base: EDX}.Offset(12), ECX)
+	MOVL(Mem{Base: R10}.Offset(12), EDX)
+	MOVL(Mem{Base: R10}.Offset(28), R8L)
+	MOVL(Mem{Base: R10}.Offset(8), EAX)
+	MOVL(EDX, Mem{Base: R12}.Offset(32))
+	MOVL(ECX, Mem{Base: R12}.Offset(36))
+	MOVL(R8L, Mem{Base: R12}.Offset(40))
+	MOVL(EAX, Mem{Base: R12}.Offset(44))
+	MOVQ(Imm(1634760805), RDX)
+	MOVQ(Imm(857760878), RCX)
+	MOVQ(Imm(2036477234), R8)
+	MOVQ(Imm(1797285236), RAX)
+	MOVL(EDX, Mem{Base: R12}.Offset(48))
+	MOVL(ECX, Mem{Base: R12}.Offset(52))
+	MOVL(R8L, Mem{Base: R12}.Offset(56))
+	MOVL(EAX, Mem{Base: R12}.Offset(60))
+	CMPQ(R9, U32(256))
+	JB(LabelRef("BYTESBETWEEN1AND255"))
+	MOVOA(Mem{Base: R12}.Offset(48), X0)
+	PSHUFL(Imm(0x55), X0, X1)
+	PSHUFL(Imm(0xAA), X0, X2)
+	PSHUFL(Imm(0xFF), X0, X3)
+	PSHUFL(Imm(0x00), X0, X0)
+	MOVOA(X1, Mem{Base: R12}.Offset(64))
+	MOVOA(X2, Mem{Base: R12}.Offset(80))
+	MOVOA(X3, Mem{Base: R12}.Offset(96))
+	MOVOA(X0, Mem{Base: R12}.Offset(112))
+	MOVOA(Mem{Base: R12}.Offset(0), X0)
+	PSHUFL(Imm(0xAA), X0, X1)
+	PSHUFL(Imm(0xFF), X0, X2)
+	PSHUFL(Imm(0x00), X0, X3)
+	PSHUFL(Imm(0x55), X0, X0)
+	MOVOA(X1, Mem{Base: R12}.Offset(128))
+	MOVOA(X2, Mem{Base: R12}.Offset(144))
+	MOVOA(X3, Mem{Base: R12}.Offset(160))
+	MOVOA(X0, Mem{Base: R12}.Offset(176))
+	MOVOA(Mem{Base: R12}.Offset(16), X0)
+	PSHUFL(Imm(0xFF), X0, X1)
+	PSHUFL(Imm(0x55), X0, X2)
+	PSHUFL(Imm(0xAA), X0, X0)
+	MOVOA(X1, Mem{Base: R12}.Offset(192))
+	MOVOA(X2, Mem{Base: R12}.Offset(208))
+	MOVOA(X0, Mem{Base: R12}.Offset(224))
+	MOVOA(Mem{Base: R12}.Offset(32), X0)
+	PSHUFL(Imm(0x00), X0, X1)
+	PSHUFL(Imm(0xAA), X0, X2)
+	PSHUFL(Imm(0xFF), X0, X0)
+	MOVOA(X1, Mem{Base: R12}.Offset(240))
+	MOVOA(X2, Mem{Base: R12}.Offset(256))
+	MOVOA(X0, Mem{Base: R12}.Offset(272))
+
+}
+
+func BYTESATLEAST256() {
+	Label("BYTESATLEAST256")
+	MOVL(Mem{Base: R12}.Offset(16), EDX)
+	MOVL(Mem{Base: R12}.Offset(36), ECX)
+	MOVL(EDX, Mem{Base: R12}.Offset(288))
+	MOVL(ECX, Mem{Base: R12}.Offset(304))
+	SHLQ(Imm(32), RCX)
+	ADDQ(RCX, RDX)
+	ADDQ(Imm(1), RDX)
+	MOVQ(RDX, RCX)
+	SHRQ(Imm(32), RCX)
+	MOVL(EDX, Mem{Base: R12}.Offset(292))
+	MOVL(ECX, Mem{Base: R12}.Offset(308))
+	ADDQ(Imm(1), RDX)
+	MOVQ(RDX, RCX)
+	SHRQ(Imm(32), RCX)
+	MOVL(EDX, Mem{Base: R12}.Offset(296))
+	MOVL(ECX, Mem{Base: R12}.Offset(312))
+	ADDQ(Imm(1), RDX)
+	MOVQ(RDX, RCX)
+	SHRQ(Imm(32), RCX)
+	MOVL(EDX, Mem{Base: R12}.Offset(300))
+	MOVL(ECX, Mem{Base: R12}.Offset(316))
+	ADDQ(Imm(1), RDX)
+	MOVQ(RDX, RCX)
+	SHRQ(Imm(32), RCX)
+	MOVL(EDX, Mem{Base: R12}.Offset(16))
+	MOVL(ECX, Mem{Base: R12}.Offset(36))
+	MOVQ(R9, Mem{Base: R12}.Offset(352))
+	MOVQ(U32(20), RDX)
+	MOVOA(Mem{Base: R12}.Offset(64), X0)
+	MOVOA(Mem{Base: R12}.Offset(80), X1)
+	MOVOA(Mem{Base: R12}.Offset(96), X2)
+	MOVOA(Mem{Base: R12}.Offset(256), X3)
+	MOVOA(Mem{Base: R12}.Offset(272), X4)
+	MOVOA(Mem{Base: R12}.Offset(128), X5)
+	MOVOA(Mem{Base: R12}.Offset(144), X6)
+	MOVOA(Mem{Base: R12}.Offset(176), X7)
+	MOVOA(Mem{Base: R12}.Offset(192), X8)
+	MOVOA(Mem{Base: R12}.Offset(208), X9)
+	MOVOA(Mem{Base: R12}.Offset(224), X10)
+	MOVOA(Mem{Base: R12}.Offset(304), X11)
+	MOVOA(Mem{Base: R12}.Offset(112), X12)
+	MOVOA(Mem{Base: R12}.Offset(160), X13)
+	MOVOA(Mem{Base: R12}.Offset(240), X14)
+	MOVOA(Mem{Base: R12}.Offset(288), X15)
+}
+
+func MAINLOOP1() {
+	Label("MAINLOOP1")
+	MOVOA(X1, Mem{Base: R12}.Offset(320))
+	MOVOA(X2, Mem{Base: R12}.Offset(336))
+	MOVOA(X13, X1)
+	PADDL(X12, X1)
+	MOVOA(X1, X2)
+	PSLLL(Imm(7), X1)
+	PXOR(X1, X14)
+	PSRLL(Imm(25), X2)
+	PXOR(X2, X14)
+	MOVOA(X7, X1)
+	PADDL(X0, X1)
+	MOVOA(X1, X2)
+	PSLLL(Imm(7), X1)
+	PXOR(X1, X11)
+	PSRLL(Imm(25), X2)
+	PXOR(X2, X11)
+	MOVOA(X12, X1)
+	PADDL(X14, X1)
+	MOVOA(X1, X2)
+	PSLLL(Imm(9), X1)
+	PXOR(X1, X15)
+	PSRLL(Imm(23), X2)
+	PXOR(X2, X15)
+	MOVOA(X0, X1)
+	PADDL(X11, X1)
+	MOVOA(X1, X2)
+	PSLLL(Imm(9), X1)
+	PXOR(X1, X9)
+	PSRLL(Imm(23), X2)
+	PXOR(X2, X9)
+	MOVOA(X14, X1)
+	PADDL(X15, X1)
+	MOVOA(X1, X2)
+	PSLLL(Imm(13), X1)
+	PXOR(X1, X13)
+	PSRLL(Imm(19), X2)
+	PXOR(X2, X13)
+	MOVOA(X11, X1)
+	PADDL(X9, X1)
+	MOVOA(X1, X2)
+	PSLLL(Imm(13), X1)
+	PXOR(X1, X7)
+	PSRLL(Imm(19), X2)
+	PXOR(X2, X7)
+	MOVOA(X15, X1)
+	PADDL(X13, X1)
+	MOVOA(X1, X2)
+	PSLLL(Imm(18), X1)
+	PXOR(X1, X12)
+	PSRLL(Imm(14), X2)
+	PXOR(X2, X12)
+	MOVOA(Mem{Base: R12}.Offset(320), X1)
+	MOVOA(X12, Mem{Base: R12}.Offset(320))
+	MOVOA(X9, X2)
+	PADDL(X7, X2)
+	MOVOA(X2, X12)
+	PSLLL(Imm(18), X2)
+	PXOR(X2, X0)
+	PSRLL(Imm(14), X12)
+	PXOR(X12, X0)
+	MOVOA(X5, X2)
+	PADDL(X1, X2)
+	MOVOA(X2, X12)
+	PSLLL(Imm(7), X2)
+	PXOR(X2, X3)
+	PSRLL(Imm(25), X12)
+	PXOR(X12, X3)
+	MOVOA(Mem{Base: R12}.Offset(336), X2)
+	MOVOA(X0, Mem{Base: R12}.Offset(336))
+	MOVOA(X6, X0)
+	PADDL(X2, X0)
+	MOVOA(X0, X12)
+	PSLLL(Imm(7), X0)
+	PXOR(X0, X4)
+	PSRLL(Imm(25), X12)
+	PXOR(X12, X4)
+	MOVOA(X1, X0)
+	PADDL(X3, X0)
+	MOVOA(X0, X12)
+	PSLLL(Imm(9), X0)
+	PXOR(X0, X10)
+	PSRLL(Imm(23), X12)
+	PXOR(X12, X10)
+	MOVOA(X2, X0)
+	PADDL(X4, X0)
+	MOVOA(X0, X12)
+	PSLLL(Imm(9), X0)
+	PXOR(X0, X8)
+	PSRLL(Imm(23), X12)
+	PXOR(X12, X8)
+	MOVOA(X3, X0)
+	PADDL(X10, X0)
+	MOVOA(X0, X12)
+	PSLLL(Imm(13), X0)
+	PXOR(X0, X5)
+	PSRLL(Imm(19), X12)
+	PXOR(X12, X5)
+	MOVOA(X4, X0)
+	PADDL(X8, X0)
+	MOVOA(X0, X12)
+	PSLLL(Imm(13), X0)
+	PXOR(X0, X6)
+	PSRLL(Imm(19), X12)
+	PXOR(X12, X6)
+	MOVOA(X10, X0)
+	PADDL(X5, X0)
+	MOVOA(X0, X12)
+	PSLLL(Imm(18), X0)
+	PXOR(X0, X1)
+	PSRLL(Imm(14), X12)
+	PXOR(X12, X1)
+	MOVOA(Mem{Base: R12}.Offset(320), X0)
+	MOVOA(X1, Mem{Base: R12}.Offset(320))
+	MOVOA(X4, X1)
+	PADDL(X0, X1)
+	MOVOA(X1, X12)
+	PSLLL(Imm(7), X1)
+	PXOR(X1, X7)
+	PSRLL(Imm(25), X12)
+	PXOR(X12, X7)
+	MOVOA(X8, X1)
+	PADDL(X6, X1)
+	MOVOA(X1, X12)
+	PSLLL(Imm(18), X1)
+	PXOR(X1, X2)
+	PSRLL(Imm(14), X12)
+	PXOR(X12, X2)
+	MOVOA(Mem{Base: R12}.Offset(336), X12)
+	MOVOA(X2, Mem{Base: R12}.Offset(336))
+	MOVOA(X14, X1)
+	PADDL(X12, X1)
+	MOVOA(X1, X2)
+	PSLLL(Imm(7), X1)
+	PXOR(X1, X5)
+	PSRLL(Imm(25), X2)
+	PXOR(X2, X5)
+	MOVOA(X0, X1)
+	PADDL(X7, X1)
+	MOVOA(X1, X2)
+	PSLLL(Imm(9), X1)
+	PXOR(X1, X10)
+	PSRLL(Imm(23), X2)
+	PXOR(X2, X10)
+	MOVOA(X12, X1)
+	PADDL(X5, X1)
+	MOVOA(X1, X2)
+	PSLLL(Imm(9), X1)
+	PXOR(X1, X8)
+	PSRLL(Imm(23), X2)
+	PXOR(X2, X8)
+	MOVOA(X7, X1)
+	PADDL(X10, X1)
+	MOVOA(X1, X2)
+	PSLLL(Imm(13), X1)
+	PXOR(X1, X4)
+	PSRLL(Imm(19), X2)
+	PXOR(X2, X4)
+	MOVOA(X5, X1)
+	PADDL(X8, X1)
+	MOVOA(X1, X2)
+	PSLLL(Imm(13), X1)
+	PXOR(X1, X14)
+	PSRLL(Imm(19), X2)
+	PXOR(X2, X14)
+	MOVOA(X10, X1)
+	PADDL(X4, X1)
+	MOVOA(X1, X2)
+	PSLLL(Imm(18), X1)
+	PXOR(X1, X0)
+	PSRLL(Imm(14), X2)
+	PXOR(X2, X0)
+	MOVOA(Mem{Base: R12}.Offset(320), X1)
+	MOVOA(X0, Mem{Base: R12}.Offset(320))
+	MOVOA(X8, X0)
+	PADDL(X14, X0)
+	MOVOA(X0, X2)
+	PSLLL(Imm(18), X0)
+	PXOR(X0, X12)
+	PSRLL(Imm(14), X2)
+	PXOR(X2, X12)
+	MOVOA(X11, X0)
+	PADDL(X1, X0)
+	MOVOA(X0, X2)
+	PSLLL(Imm(7), X0)
+	PXOR(X0, X6)
+	PSRLL(Imm(25), X2)
+	PXOR(X2, X6)
+	MOVOA(Mem{Base: R12}.Offset(336), X2)
+	MOVOA(X12, Mem{Base: R12}.Offset(336))
+	MOVOA(X3, X0)
+	PADDL(X2, X0)
+	MOVOA(X0, X12)
+	PSLLL(Imm(7), X0)
+	PXOR(X0, X13)
+	PSRLL(Imm(25), X12)
+	PXOR(X12, X13)
+	MOVOA(X1, X0)
+	PADDL(X6, X0)
+	MOVOA(X0, X12)
+	PSLLL(Imm(9), X0)
+	PXOR(X0, X15)
+	PSRLL(Imm(23), X12)
+	PXOR(X12, X15)
+	MOVOA(X2, X0)
+	PADDL(X13, X0)
+	MOVOA(X0, X12)
+	PSLLL(Imm(9), X0)
+	PXOR(X0, X9)
+	PSRLL(Imm(23), X12)
+	PXOR(X12, X9)
+	MOVOA(X6, X0)
+	PADDL(X15, X0)
+	MOVOA(X0, X12)
+	PSLLL(Imm(13), X0)
+	PXOR(X0, X11)
+	PSRLL(Imm(19), X12)
+	PXOR(X12, X11)
+	MOVOA(X13, X0)
+	PADDL(X9, X0)
+	MOVOA(X0, X12)
+	PSLLL(Imm(13), X0)
+	PXOR(X0, X3)
+	PSRLL(Imm(19), X12)
+	PXOR(X12, X3)
+	MOVOA(X15, X0)
+	PADDL(X11, X0)
+	MOVOA(X0, X12)
+	PSLLL(Imm(18), X0)
+	PXOR(X0, X1)
+	PSRLL(Imm(14), X12)
+	PXOR(X12, X1)
+	MOVOA(X9, X0)
+	PADDL(X3, X0)
+	MOVOA(X0, X12)
+	PSLLL(Imm(18), X0)
+	PXOR(X0, X2)
+	PSRLL(Imm(14), X12)
+	PXOR(X12, X2)
+	MOVOA(Mem{Base: R12}.Offset(320), X12)
+	MOVOA(Mem{Base: R12}.Offset(336), X0)
+	SUBQ(Imm(2), RDX)
+	JA(LabelRef("MAINLOOP1"))
+	PADDL(Mem{Base: R12}.Offset(112), X12)
+	PADDL(Mem{Base: R12}.Offset(176), X7)
+	PADDL(Mem{Base: R12}.Offset(224), X10)
+	PADDL(Mem{Base: R12}.Offset(272), X4)
+	MOVD(X12, EDX)
+	MOVD(X7, ECX)
+	MOVD(X10, R8)
+	MOVD(X4, R9)
+	PSHUFL(Imm(0x39), X12, X12)
+	PSHUFL(Imm(0x39), X7, X7)
+	PSHUFL(Imm(0x39), X10, X10)
+	PSHUFL(Imm(0x39), X4, X4)
+	XORL(Mem{Base: SI}.Offset(0), EDX)
+	XORL(Mem{Base: SI}.Offset(4), ECX)
+	XORL(Mem{Base: SI}.Offset(8), R8L)
+	XORL(Mem{Base: SI}.Offset(12), R9L)
+	MOVL(EDX, Mem{Base: DI}.Offset(0))
+	MOVL(ECX, Mem{Base: DI}.Offset(4))
+	MOVL(R8L, Mem{Base: DI}.Offset(8))
+	MOVL(R9L, Mem{Base: DI}.Offset(12))
+	MOVD(X12, EDX)
+	MOVD(X7, ECX)
+	MOVD(X10, R8)
+	MOVD(X4, R9)
+	PSHUFL(Imm(0x39), X12, X12)
+	PSHUFL(Imm(0x39), X7, X7)
+	PSHUFL(Imm(0x39), X10, X10)
+	PSHUFL(Imm(0x39), X4, X4)
+	XORL(Mem{Base: SI}.Offset(64), EDX)
+	XORL(Mem{Base: SI}.Offset(68), ECX)
+	XORL(Mem{Base: SI}.Offset(72), R8L)
+	XORL(Mem{Base: SI}.Offset(76), R9L)
+	MOVL(EDX, Mem{Base: DI}.Offset(64))
+	MOVL(ECX, Mem{Base: DI}.Offset(68))
+	MOVL(R8L, Mem{Base: DI}.Offset(72))
+	MOVL(R9L, Mem{Base: DI}.Offset(76))
+	MOVD(X12, EDX)
+	MOVD(X7, ECX)
+	MOVD(X10, R8)
+	MOVD(X4, R9)
+	PSHUFL(Imm(0x39), X12, X12)
+	PSHUFL(Imm(0x39), X7, X7)
+	PSHUFL(Imm(0x39), X10, X10)
+	PSHUFL(Imm(0x39), X4, X4)
+	XORL(Mem{Base: SI}.Offset(128), EDX)
+	XORL(Mem{Base: SI}.Offset(132), ECX)
+	XORL(Mem{Base: SI}.Offset(136), R8L)
+	XORL(Mem{Base: SI}.Offset(140), R9L)
+	MOVL(EDX, Mem{Base: DI}.Offset(128))
+	MOVL(ECX, Mem{Base: DI}.Offset(132))
+	MOVL(R8L, Mem{Base: DI}.Offset(136))
+	MOVL(R9L, Mem{Base: DI}.Offset(140))
+	MOVD(X12, EDX)
+	MOVD(X7, ECX)
+	MOVD(X10, R8)
+	MOVD(X4, R9)
+	XORL(Mem{Base: SI}.Offset(192), EDX)
+	XORL(Mem{Base: SI}.Offset(196), ECX)
+	XORL(Mem{Base: SI}.Offset(200), R8L)
+	XORL(Mem{Base: SI}.Offset(204), R9L)
+	MOVL(EDX, Mem{Base: DI}.Offset(192))
+	MOVL(ECX, Mem{Base: DI}.Offset(196))
+	MOVL(R8L, Mem{Base: DI}.Offset(200))
+	MOVL(R9L, Mem{Base: DI}.Offset(204))
+	PADDL(Mem{Base: R12}.Offset(240), X14)
+	PADDL(Mem{Base: R12}.Offset(64), X0)
+	PADDL(Mem{Base: R12}.Offset(128), X5)
+	PADDL(Mem{Base: R12}.Offset(192), X8)
+	MOVD(X14, EDX)
+	MOVD(X0, ECX)
+	MOVD(X5, R8)
+	MOVD(X8, R9)
+	PSHUFL(Imm(0x39), X14, X14)
+	PSHUFL(Imm(0x39), X0, X0)
+	PSHUFL(Imm(0x39), X5, X5)
+	PSHUFL(Imm(0x39), X8, X8)
+	XORL(Mem{Base: SI}.Offset(16), EDX)
+	XORL(Mem{Base: SI}.Offset(20), ECX)
+	XORL(Mem{Base: SI}.Offset(24), R8L)
+	XORL(Mem{Base: SI}.Offset(28), R9L)
+	MOVL(EDX, Mem{Base: DI}.Offset(16))
+	MOVL(ECX, Mem{Base: DI}.Offset(20))
+	MOVL(R8L, Mem{Base: DI}.Offset(24))
+	MOVL(R9L, Mem{Base: DI}.Offset(28))
+	MOVD(X14, EDX)
+	MOVD(X0, ECX)
+	MOVD(X5, R8)
+	MOVD(X8, R9)
+	PSHUFL(Imm(0x39), X14, X14)
+	PSHUFL(Imm(0x39), X0, X0)
+	PSHUFL(Imm(0x39), X5, X5)
+	PSHUFL(Imm(0x39), X8, X8)
+	XORL(Mem{Base: SI}.Offset(80), EDX)
+	XORL(Mem{Base: SI}.Offset(84), ECX)
+	XORL(Mem{Base: SI}.Offset(88), R8L)
+	XORL(Mem{Base: SI}.Offset(92), R9L)
+	MOVL(EDX, Mem{Base: DI}.Offset(80))
+	MOVL(ECX, Mem{Base: DI}.Offset(84))
+	MOVL(R8L, Mem{Base: DI}.Offset(88))
+	MOVL(R9L, Mem{Base: DI}.Offset(92))
+	MOVD(X14, EDX)
+	MOVD(X0, ECX)
+	MOVD(X5, R8)
+	MOVD(X8, R9)
+	PSHUFL(Imm(0x39), X14, X14)
+	PSHUFL(Imm(0x39), X0, X0)
+	PSHUFL(Imm(0x39), X5, X5)
+	PSHUFL(Imm(0x39), X8, X8)
+	XORL(Mem{Base: SI}.Offset(144), EDX)
+	XORL(Mem{Base: SI}.Offset(148), ECX)
+	XORL(Mem{Base: SI}.Offset(152), R8L)
+	XORL(Mem{Base: SI}.Offset(156), R9L)
+	MOVL(EDX, Mem{Base: DI}.Offset(144))
+	MOVL(ECX, Mem{Base: DI}.Offset(148))
+	MOVL(R8L, Mem{Base: DI}.Offset(152))
+	MOVL(R9L, Mem{Base: DI}.Offset(156))
+	MOVD(X14, EDX)
+	MOVD(X0, ECX)
+	MOVD(X5, R8)
+	MOVD(X8, R9)
+	XORL(Mem{Base: SI}.Offset(208), EDX)
+	XORL(Mem{Base: SI}.Offset(212), ECX)
+	XORL(Mem{Base: SI}.Offset(216), R8L)
+	XORL(Mem{Base: SI}.Offset(220), R9L)
+	MOVL(EDX, Mem{Base: DI}.Offset(208))
+	MOVL(ECX, Mem{Base: DI}.Offset(212))
+	MOVL(R8L, Mem{Base: DI}.Offset(216))
+	MOVL(R9L, Mem{Base: DI}.Offset(220))
+	PADDL(Mem{Base: R12}.Offset(288), X15)
+	PADDL(Mem{Base: R12}.Offset(304), X11)
+	PADDL(Mem{Base: R12}.Offset(80), X1)
+	PADDL(Mem{Base: R12}.Offset(144), X6)
+	MOVD(X15, EDX)
+	MOVD(X11, ECX)
+	MOVD(X1, R8)
+	MOVD(X6, R9)
+	PSHUFL(Imm(0x39), X15, X15)
+	PSHUFL(Imm(0x39), X11, X11)
+	PSHUFL(Imm(0x39), X1, X1)
+	PSHUFL(Imm(0x39), X6, X6)
+	XORL(Mem{Base: SI}.Offset(32), EDX)
+	XORL(Mem{Base: SI}.Offset(36), ECX)
+	XORL(Mem{Base: SI}.Offset(40), R8L)
+	XORL(Mem{Base: SI}.Offset(44), R9L)
+	MOVL(EDX, Mem{Base: DI}.Offset(32))
+	MOVL(ECX, Mem{Base: DI}.Offset(36))
+	MOVL(R8L, Mem{Base: DI}.Offset(40))
+	MOVL(R9L, Mem{Base: DI}.Offset(44))
+	MOVD(X15, EDX)
+	MOVD(X11, ECX)
+	MOVD(X1, R8)
+	MOVD(X6, R9)
+	PSHUFL(Imm(0x39), X15, X15)
+	PSHUFL(Imm(0x39), X11, X11)
+	PSHUFL(Imm(0x39), X1, X1)
+	PSHUFL(Imm(0x39), X6, X6)
+	XORL(Mem{Base: SI}.Offset(96), EDX)
+	XORL(Mem{Base: SI}.Offset(100), ECX)
+	XORL(Mem{Base: SI}.Offset(104), R8L)
+	XORL(Mem{Base: SI}.Offset(108), R9L)
+	MOVL(EDX, Mem{Base: DI}.Offset(96))
+	MOVL(ECX, Mem{Base: DI}.Offset(100))
+	MOVL(R8L, Mem{Base: DI}.Offset(104))
+	MOVL(R9L, Mem{Base: DI}.Offset(108))
+	MOVD(X15, EDX)
+	MOVD(X11, ECX)
+	MOVD(X1, R8)
+	MOVD(X6, R9)
+	PSHUFL(Imm(0x39), X15, X15)
+	PSHUFL(Imm(0x39), X11, X11)
+	PSHUFL(Imm(0x39), X1, X1)
+	PSHUFL(Imm(0x39), X6, X6)
+	XORL(Mem{Base: SI}.Offset(160), EDX)
+	XORL(Mem{Base: SI}.Offset(164), ECX)
+	XORL(Mem{Base: SI}.Offset(168), R8L)
+	XORL(Mem{Base: SI}.Offset(172), R9L)
+	MOVL(EDX, Mem{Base: DI}.Offset(160))
+	MOVL(ECX, Mem{Base: DI}.Offset(164))
+	MOVL(R8L, Mem{Base: DI}.Offset(168))
+	MOVL(R9L, Mem{Base: DI}.Offset(172))
+	MOVD(X15, EDX)
+	MOVD(X11, ECX)
+	MOVD(X1, R8)
+	MOVD(X6, R9)
+	XORL(Mem{Base: SI}.Offset(224), EDX)
+	XORL(Mem{Base: SI}.Offset(228), ECX)
+	XORL(Mem{Base: SI}.Offset(232), R8L)
+	XORL(Mem{Base: SI}.Offset(236), R9L)
+	MOVL(EDX, Mem{Base: DI}.Offset(224))
+	MOVL(ECX, Mem{Base: DI}.Offset(228))
+	MOVL(R8L, Mem{Base: DI}.Offset(232))
+	MOVL(R9L, Mem{Base: DI}.Offset(236))
+	PADDL(Mem{Base: R12}.Offset(160), X13)
+	PADDL(Mem{Base: R12}.Offset(208), X9)
+	PADDL(Mem{Base: R12}.Offset(256), X3)
+	PADDL(Mem{Base: R12}.Offset(96), X2)
+	MOVD(X13, EDX)
+	MOVD(X9, ECX)
+	MOVD(X3, R8)
+	MOVD(X2, R9)
+	PSHUFL(Imm(0x39), X13, X13)
+	PSHUFL(Imm(0x39), X9, X9)
+	PSHUFL(Imm(0x39), X3, X3)
+	PSHUFL(Imm(0x39), X2, X2)
+	XORL(Mem{Base: SI}.Offset(48), EDX)
+	XORL(Mem{Base: SI}.Offset(52), ECX)
+	XORL(Mem{Base: SI}.Offset(56), R8L)
+	XORL(Mem{Base: SI}.Offset(60), R9L)
+	MOVL(EDX, Mem{Base: DI}.Offset(48))
+	MOVL(ECX, Mem{Base: DI}.Offset(52))
+	MOVL(R8L, Mem{Base: DI}.Offset(56))
+	MOVL(R9L, Mem{Base: DI}.Offset(60))
+	MOVD(X13, EDX)
+	MOVD(X9, ECX)
+	MOVD(X3, R8)
+	MOVD(X2, R9)
+	PSHUFL(Imm(0x39), X13, X13)
+	PSHUFL(Imm(0x39), X9, X9)
+	PSHUFL(Imm(0x39), X3, X3)
+	PSHUFL(Imm(0x39), X2, X2)
+	XORL(Mem{Base: SI}.Offset(112), EDX)
+	XORL(Mem{Base: SI}.Offset(116), ECX)
+	XORL(Mem{Base: SI}.Offset(120), R8L)
+	XORL(Mem{Base: SI}.Offset(124), R9L)
+	MOVL(EDX, Mem{Base: DI}.Offset(112))
+	MOVL(ECX, Mem{Base: DI}.Offset(116))
+	MOVL(R8L, Mem{Base: DI}.Offset(120))
+	MOVL(R9L, Mem{Base: DI}.Offset(124))
+	MOVD(X13, EDX)
+	MOVD(X9, ECX)
+	MOVD(X3, R8)
+	MOVD(X2, R9)
+	PSHUFL(Imm(0x39), X13, X13)
+	PSHUFL(Imm(0x39), X9, X9)
+	PSHUFL(Imm(0x39), X3, X3)
+	PSHUFL(Imm(0x39), X2, X2)
+	XORL(Mem{Base: SI}.Offset(176), EDX)
+	XORL(Mem{Base: SI}.Offset(180), ECX)
+	XORL(Mem{Base: SI}.Offset(184), R8L)
+	XORL(Mem{Base: SI}.Offset(188), R9L)
+	MOVL(EDX, Mem{Base: DI}.Offset(176))
+	MOVL(ECX, Mem{Base: DI}.Offset(180))
+	MOVL(R8L, Mem{Base: DI}.Offset(184))
+	MOVL(R9L, Mem{Base: DI}.Offset(188))
+	MOVD(X13, EDX)
+	MOVD(X9, ECX)
+	MOVD(X3, R8)
+	MOVD(X2, R9)
+	XORL(Mem{Base: SI}.Offset(240), EDX)
+	XORL(Mem{Base: SI}.Offset(244), ECX)
+	XORL(Mem{Base: SI}.Offset(248), R8L)
+	XORL(Mem{Base: SI}.Offset(252), R9L)
+	MOVL(EDX, Mem{Base: DI}.Offset(240))
+	MOVL(ECX, Mem{Base: DI}.Offset(244))
+	MOVL(R8L, Mem{Base: DI}.Offset(248))
+	MOVL(R9L, Mem{Base: DI}.Offset(252))
+	MOVQ(Mem{Base: R12}.Offset(352), R9)
+	SUBQ(U32(256), R9)
+	ADDQ(U32(256), RSI)
+	ADDQ(U32(256), RDI)
+	CMPQ(R9, U32(256))
+	JAE(LabelRef("BYTESATLEAST256"))
+	CMPQ(R9, Imm(0))
+	JBE(LabelRef("DONE"))
+}
+
+func BYTESBETWEEN1AND255() {
+	Label("BYTESBETWEEN1AND255")
+	CMPQ(R9, Imm(64))
+	JAE(LabelRef("NOCOPY"))
+	MOVQ(RDI, RDX)
+	LEAQ(Mem{Base: R12}.Offset(360), RDI)
+	MOVQ(R9, RCX)
+	// Hack to get Avo to emit:
+	// 	REP; MOVSB
+	Instruction(&ir.Instruction{Opcode: "REP; MOVSB"})
+	LEAQ(Mem{Base: R12}.Offset(360), RDI)
+	LEAQ(Mem{Base: R12}.Offset(360), RSI)
+}
+
+func NOCOPY() {
+	Label("NOCOPY")
+	MOVQ(R9, Mem{Base: R12}.Offset(352))
+	MOVOA(Mem{Base: R12}.Offset(48), X0)
+	MOVOA(Mem{Base: R12}.Offset(0), X1)
+	MOVOA(Mem{Base: R12}.Offset(16), X2)
+	MOVOA(Mem{Base: R12}.Offset(32), X3)
+	MOVOA(X1, X4)
+	MOVQ(U32(20), RCX)
+}
+
+func MAINLOOP2() {
+	Label("MAINLOOP2")
+	PADDL(X0, X4)
+	MOVOA(X0, X5)
+	MOVOA(X4, X6)
+	PSLLL(Imm(7), X4)
+	PSRLL(Imm(25), X6)
+	PXOR(X4, X3)
+	PXOR(X6, X3)
+	PADDL(X3, X5)
+	MOVOA(X3, X4)
+	MOVOA(X5, X6)
+	PSLLL(Imm(9), X5)
+	PSRLL(Imm(23), X6)
+	PXOR(X5, X2)
+	PSHUFL(Imm(0x93), X3, X3)
+	PXOR(X6, X2)
+	PADDL(X2, X4)
+	MOVOA(X2, X5)
+	MOVOA(X4, X6)
+	PSLLL(Imm(13), X4)
+	PSRLL(Imm(19), X6)
+	PXOR(X4, X1)
+	PSHUFL(Imm(0x4E), X2, X2)
+	PXOR(X6, X1)
+	PADDL(X1, X5)
+	MOVOA(X3, X4)
+	MOVOA(X5, X6)
+	PSLLL(Imm(18), X5)
+	PSRLL(Imm(14), X6)
+	PXOR(X5, X0)
+	PSHUFL(Imm(0x39), X1, X1)
+	PXOR(X6, X0)
+	PADDL(X0, X4)
+	MOVOA(X0, X5)
+	MOVOA(X4, X6)
+	PSLLL(Imm(7), X4)
+	PSRLL(Imm(25), X6)
+	PXOR(X4, X1)
+	PXOR(X6, X1)
+	PADDL(X1, X5)
+	MOVOA(X1, X4)
+	MOVOA(X5, X6)
+	PSLLL(Imm(9), X5)
+	PSRLL(Imm(23), X6)
+	PXOR(X5, X2)
+	PSHUFL(Imm(0x93), X1, X1)
+	PXOR(X6, X2)
+	PADDL(X2, X4)
+	MOVOA(X2, X5)
+	MOVOA(X4, X6)
+	PSLLL(Imm(13), X4)
+	PSRLL(Imm(19), X6)
+	PXOR(X4, X3)
+	PSHUFL(Imm(0x4E), X2, X2)
+	PXOR(X6, X3)
+	PADDL(X3, X5)
+	MOVOA(X1, X4)
+	MOVOA(X5, X6)
+	PSLLL(Imm(18), X5)
+	PSRLL(Imm(14), X6)
+	PXOR(X5, X0)
+	PSHUFL(Imm(0x39), X3, X3)
+	PXOR(X6, X0)
+	PADDL(X0, X4)
+	MOVOA(X0, X5)
+	MOVOA(X4, X6)
+	PSLLL(Imm(7), X4)
+	PSRLL(Imm(25), X6)
+	PXOR(X4, X3)
+	PXOR(X6, X3)
+	PADDL(X3, X5)
+	MOVOA(X3, X4)
+	MOVOA(X5, X6)
+	PSLLL(Imm(9), X5)
+	PSRLL(Imm(23), X6)
+	PXOR(X5, X2)
+	PSHUFL(Imm(0x93), X3, X3)
+	PXOR(X6, X2)
+	PADDL(X2, X4)
+	MOVOA(X2, X5)
+	MOVOA(X4, X6)
+	PSLLL(Imm(13), X4)
+	PSRLL(Imm(19), X6)
+	PXOR(X4, X1)
+	PSHUFL(Imm(0x4E), X2, X2)
+	PXOR(X6, X1)
+	PADDL(X1, X5)
+	MOVOA(X3, X4)
+	MOVOA(X5, X6)
+	PSLLL(Imm(18), X5)
+	PSRLL(Imm(14), X6)
+	PXOR(X5, X0)
+	PSHUFL(Imm(0x39), X1, X1)
+	PXOR(X6, X0)
+	PADDL(X0, X4)
+	MOVOA(X0, X5)
+	MOVOA(X4, X6)
+	PSLLL(Imm(7), X4)
+	PSRLL(Imm(25), X6)
+	PXOR(X4, X1)
+	PXOR(X6, X1)
+	PADDL(X1, X5)
+	MOVOA(X1, X4)
+	MOVOA(X5, X6)
+	PSLLL(Imm(9), X5)
+	PSRLL(Imm(23), X6)
+	PXOR(X5, X2)
+	PSHUFL(Imm(0x93), X1, X1)
+	PXOR(X6, X2)
+	PADDL(X2, X4)
+	MOVOA(X2, X5)
+	MOVOA(X4, X6)
+	PSLLL(Imm(13), X4)
+	PSRLL(Imm(19), X6)
+	PXOR(X4, X3)
+	PSHUFL(Imm(0x4E), X2, X2)
+	PXOR(X6, X3)
+	SUBQ(Imm(4), RCX)
+	PADDL(X3, X5)
+	MOVOA(X1, X4)
+	MOVOA(X5, X6)
+	PSLLL(Imm(18), X5)
+	PXOR(X7, X7)
+	PSRLL(Imm(14), X6)
+	PXOR(X5, X0)
+	PSHUFL(Imm(0x39), X3, X3)
+	PXOR(X6, X0)
+	JA(LabelRef("MAINLOOP2"))
+	PADDL(Mem{Base: R12}.Offset(48), X0)
+	PADDL(Mem{Base: R12}.Offset(0), X1)
+	PADDL(Mem{Base: R12}.Offset(16), X2)
+	PADDL(Mem{Base: R12}.Offset(32), X3)
+	MOVD(X0, ECX)
+	MOVD(X1, R8)
+	MOVD(X2, R9)
+	MOVD(X3, EAX)
+	PSHUFL(Imm(0x39), X0, X0)
+	PSHUFL(Imm(0x39), X1, X1)
+	PSHUFL(Imm(0x39), X2, X2)
+	PSHUFL(Imm(0x39), X3, X3)
+	XORL(Mem{Base: SI}.Offset(0), ECX)
+	XORL(Mem{Base: SI}.Offset(48), R8L)
+	XORL(Mem{Base: SI}.Offset(32), R9L)
+	XORL(Mem{Base: SI}.Offset(16), EAX)
+	MOVL(ECX, Mem{Base: DI}.Offset(0))
+	MOVL(R8L, Mem{Base: DI}.Offset(48))
+	MOVL(R9L, Mem{Base: DI}.Offset(32))
+	MOVL(EAX, Mem{Base: DI}.Offset(16))
+	MOVD(X0, ECX)
+	MOVD(X1, R8)
+	MOVD(X2, R9)
+	MOVD(X3, EAX)
+	PSHUFL(Imm(0x39), X0, X0)
+	PSHUFL(Imm(0x39), X1, X1)
+	PSHUFL(Imm(0x39), X2, X2)
+	PSHUFL(Imm(0x39), X3, X3)
+	XORL(Mem{Base: SI}.Offset(20), ECX)
+	XORL(Mem{Base: SI}.Offset(4), R8L)
+	XORL(Mem{Base: SI}.Offset(52), R9L)
+	XORL(Mem{Base: SI}.Offset(36), EAX)
+	MOVL(ECX, Mem{Base: DI}.Offset(20))
+	MOVL(R8L, Mem{Base: DI}.Offset(4))
+	MOVL(R9L, Mem{Base: DI}.Offset(52))
+	MOVL(EAX, Mem{Base: DI}.Offset(36))
+	MOVD(X0, ECX)
+	MOVD(X1, R8)
+	MOVD(X2, R9)
+	MOVD(X3, EAX)
+	PSHUFL(Imm(0x39), X0, X0)
+	PSHUFL(Imm(0x39), X1, X1)
+	PSHUFL(Imm(0x39), X2, X2)
+	PSHUFL(Imm(0x39), X3, X3)
+	XORL(Mem{Base: SI}.Offset(40), ECX)
+	XORL(Mem{Base: SI}.Offset(24), R8L)
+	XORL(Mem{Base: SI}.Offset(8), R9L)
+	XORL(Mem{Base: SI}.Offset(56), EAX)
+	MOVL(ECX, Mem{Base: DI}.Offset(40))
+	MOVL(R8L, Mem{Base: DI}.Offset(24))
+	MOVL(R9L, Mem{Base: DI}.Offset(8))
+	MOVL(EAX, Mem{Base: DI}.Offset(56))
+	MOVD(X0, ECX)
+	MOVD(X1, R8)
+	MOVD(X2, R9)
+	MOVD(X3, EAX)
+	XORL(Mem{Base: SI}.Offset(60), ECX)
+	XORL(Mem{Base: SI}.Offset(44), R8L)
+	XORL(Mem{Base: SI}.Offset(28), R9L)
+	XORL(Mem{Base: SI}.Offset(12), EAX)
+	MOVL(ECX, Mem{Base: DI}.Offset(60))
+	MOVL(R8L, Mem{Base: DI}.Offset(44))
+	MOVL(R9L, Mem{Base: DI}.Offset(28))
+	MOVL(EAX, Mem{Base: DI}.Offset(12))
+	MOVQ(Mem{Base: R12}.Offset(352), R9)
+	MOVL(Mem{Base: R12}.Offset(16), ECX)
+	MOVL(Mem{Base: R12}.Offset(36), R8L)
+	ADDQ(Imm(1), RCX)
+	SHLQ(Imm(32), R8)
+	ADDQ(R8, RCX)
+	MOVQ(RCX, R8)
+	SHRQ(Imm(32), R8)
+	MOVL(ECX, Mem{Base: R12}.Offset(16))
+	MOVL(R8L, Mem{Base: R12}.Offset(36))
+	CMPQ(R9, Imm(64))
+	JA(LabelRef("BYTESATLEAST65"))
+	JAE(LabelRef("BYTESATLEAST64"))
+	MOVQ(RDI, RSI)
+	MOVQ(RDX, RDI)
+	MOVQ(R9, RCX)
+	// Hack to get Avo to emit:
+	// 	REP; MOVSB
+	Instruction(&ir.Instruction{Opcode: "REP; MOVSB"})
+}

sha3/_asm/go.mod

@@ -4,12 +4,12 @@ go 1.22
 
 require (
 	github.com/mmcloughlin/avo v0.6.0
-	golang.org/x/crypto v0.25.0
+	golang.org/x/crypto v0.33.0
 )
 
 require (
 	golang.org/x/mod v0.19.0 // indirect
 	golang.org/x/sync v0.7.0 // indirect
-	golang.org/x/sys v0.22.0 // indirect
+	golang.org/x/sys v0.30.0 // indirect
 	golang.org/x/tools v0.23.0 // indirect
 )

sha3/_asm/go.sum

@@ -1,12 +1,12 @@
 github.com/mmcloughlin/avo v0.6.0 h1:QH6FU8SKoTLaVs80GA8TJuLNkUYl4VokHKlPhVDg4YY=
 github.com/mmcloughlin/avo v0.6.0/go.mod h1:8CoAGaCSYXtCPR+8y18Y9aB/kxb8JSS6FRI7mSkvD+8=
-golang.org/x/crypto v0.25.0 h1:ypSNr+bnYL2YhwoMt2zPxHFmbAN1KZs/njMG3hxUp30=
-golang.org/x/crypto v0.25.0/go.mod h1:T+wALwcMOSE0kXgUAnPAHqTLW+XHgcELELW8VaDgm/M=
+golang.org/x/crypto v0.33.0 h1:IOBPskki6Lysi0lo9qQvbxiQ+FvsCC/YWOecCHAixus=
+golang.org/x/crypto v0.33.0/go.mod h1:bVdXmD7IV/4GdElGPozy6U7lWdRXA4qyRVGJV57uQ5M=
 golang.org/x/mod v0.19.0 h1:fEdghXQSo20giMthA7cd28ZC+jts4amQ3YMXiP5oMQ8=
 golang.org/x/mod v0.19.0/go.mod h1:hTbmBsO62+eylJbnUtE2MGJUyE7QWk4xUqPFrRgJ+7c=
 golang.org/x/sync v0.7.0 h1:YsImfSBoP9QPYL0xyKJPq0gcaJdG3rInoqxTWbfQu9M=
 golang.org/x/sync v0.7.0/go.mod h1:Czt+wKu1gCyEFDUtn0jG5QVvpJ6rzVqr5aXyt9drQfk=
-golang.org/x/sys v0.22.0 h1:RI27ohtqKCnwULzJLqkv897zojh5/DwS/ENaMzUOaWI=
-golang.org/x/sys v0.22.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
+golang.org/x/sys v0.30.0 h1:QjkSwP/36a20jFYWkSue1YwXzLmsV5Gfq7Eiy72C1uc=
+golang.org/x/sys v0.30.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
 golang.org/x/tools v0.23.0 h1:SGsXPZ+2l4JsgaCKkx+FQ9YZ5XEtA1GZYuoDjenLjvg=
 golang.org/x/tools v0.23.0/go.mod h1:pnu6ufv6vQkll6szChhK3C3L/ruaIv5eBeztNG8wtsI=

sha3/doc.go

@@ -5,6 +5,10 @@
 // Package sha3 implements the SHA-3 fixed-output-length hash functions and
 // the SHAKE variable-output-length hash functions defined by FIPS-202.
 //
+// All types in this package also implement [encoding.BinaryMarshaler],
+// [encoding.BinaryAppender] and [encoding.BinaryUnmarshaler] to marshal and
+// unmarshal the internal state of the hash.
+//
 // Both types of hash function use the "sponge" construction and the Keccak
 // permutation. For a detailed specification see http://keccak.noekeon.org/
 //

sha3/hashes.go

@@ -48,33 +48,52 @@ func init() {
 	crypto.RegisterHash(crypto.SHA3_512, New512)
 }
 
+const (
+	dsbyteSHA3   = 0b00000110
+	dsbyteKeccak = 0b00000001
+	dsbyteShake  = 0b00011111
+	dsbyteCShake = 0b00000100
+
+	// rateK[c] is the rate in bytes for Keccak[c] where c is the capacity in
+	// bits. Given the sponge size is 1600 bits, the rate is 1600 - c bits.
+	rateK256  = (1600 - 256) / 8
+	rateK448  = (1600 - 448) / 8
+	rateK512  = (1600 - 512) / 8
+	rateK768  = (1600 - 768) / 8
+	rateK1024 = (1600 - 1024) / 8
+)
+
 func new224Generic() *state {
-	return &state{rate: 144, outputLen: 28, dsbyte: 0x06}
+	return &state{rate: rateK448, outputLen: 28, dsbyte: dsbyteSHA3}
 }
 
 func new256Generic() *state {
-	return &state{rate: 136, outputLen: 32, dsbyte: 0x06}
+	return &state{rate: rateK512, outputLen: 32, dsbyte: dsbyteSHA3}
 }
 
 func new384Generic() *state {
-	return &state{rate: 104, outputLen: 48, dsbyte: 0x06}
+	return &state{rate: rateK768, outputLen: 48, dsbyte: dsbyteSHA3}
 }
 
 func new512Generic() *state {
-	return &state{rate: 72, outputLen: 64, dsbyte: 0x06}
+	return &state{rate: rateK1024, outputLen: 64, dsbyte: dsbyteSHA3}
 }
 
 // NewLegacyKeccak256 creates a new Keccak-256 hash.
 //
 // Only use this function if you require compatibility with an existing cryptosystem
 // that uses non-standard padding. All other users should use New256 instead.
-func NewLegacyKeccak256() hash.Hash { return &state{rate: 136, outputLen: 32, dsbyte: 0x01} }
+func NewLegacyKeccak256() hash.Hash {
+	return &state{rate: rateK512, outputLen: 32, dsbyte: dsbyteKeccak}
+}
 
 // NewLegacyKeccak512 creates a new Keccak-512 hash.
 //
 // Only use this function if you require compatibility with an existing cryptosystem
 // that uses non-standard padding. All other users should use New512 instead.
-func NewLegacyKeccak512() hash.Hash { return &state{rate: 72, outputLen: 64, dsbyte: 0x01} }
+func NewLegacyKeccak512() hash.Hash {
+	return &state{rate: rateK1024, outputLen: 64, dsbyte: dsbyteKeccak}
+}
 
 // Sum224 returns the SHA3-224 digest of the data.
 func Sum224(data []byte) (digest [28]byte) {

sha3/sha3.go

@@ -4,6 +4,15 @@
 
 package sha3
 
+import (
+	"crypto/subtle"
+	"encoding/binary"
+	"errors"
+	"unsafe"
+
+	"golang.org/x/sys/cpu"
+)
+
 // spongeDirection indicates the direction bytes are flowing through the sponge.
 type spongeDirection int
 
@@ -14,16 +23,13 @@ const (
 	spongeSqueezing
 )
 
-const (
-	// maxRate is the maximum size of the internal buffer. SHAKE-256
-	// currently needs the largest buffer.
-	maxRate = 168
-)
-
 type state struct {
-	// Generic sponge components.
-	a    [25]uint64 // main state of the hash
-	rate int        // the number of bytes of state to use
+	a [1600 / 8]byte // main state of the hash
+
+	// a[n:rate] is the buffer. If absorbing, it's the remaining space to XOR
+	// into before running the permutation. If squeezing, it's the remaining
+	// output to produce before running the permutation.
+	n, rate int
 
 	// dsbyte contains the "domain separation" bits and the first bit of
 	// the padding. Sections 6.1 and 6.2 of [1] separate the outputs of the
@@ -39,10 +45,6 @@ type state struct {
 	//      Extendable-Output Functions (May 2014)"
 	dsbyte byte
 
-	i, n    int // storage[i:n] is the buffer, i is only used while squeezing
-	storage [maxRate]byte
-
-	// Specific to SHA-3 and SHAKE.
 	outputLen int             // the default output size in bytes
 	state     spongeDirection // whether the sponge is absorbing or squeezing
 }
@@ -61,7 +63,7 @@ func (d *state) Reset() {
 		d.a[i] = 0
 	}
 	d.state = spongeAbsorbing
-	d.i, d.n = 0, 0
+	d.n = 0
 }
 
 func (d *state) clone() *state {
@@ -69,22 +71,25 @@ func (d *state) clone() *state {
 	return &ret
 }
 
-// permute applies the KeccakF-1600 permutation. It handles
-// any input-output buffering.
+// permute applies the KeccakF-1600 permutation.
 func (d *state) permute() {
-	switch d.state {
-	case spongeAbsorbing:
-		// If we're absorbing, we need to xor the input into the state
-		// before applying the permutation.
-		xorIn(d, d.storage[:d.rate])
-		d.n = 0
-		keccakF1600(&d.a)
-	case spongeSqueezing:
-		// If we're squeezing, we need to apply the permutation before
-		// copying more output.
-		keccakF1600(&d.a)
-		d.i = 0
-		copyOut(d, d.storage[:d.rate])
+	var a *[25]uint64
+	if cpu.IsBigEndian {
+		a = new([25]uint64)
+		for i := range a {
+			a[i] = binary.LittleEndian.Uint64(d.a[i*8:])
+		}
+	} else {
+		a = (*[25]uint64)(unsafe.Pointer(&d.a))
+	}
+
+	keccakF1600(a)
+	d.n = 0
+
+	if cpu.IsBigEndian {
+		for i := range a {
+			binary.LittleEndian.PutUint64(d.a[i*8:], a[i])
+		}
 	}
 }
 
@@ -92,53 +97,36 @@ func (d *state) permute() {
 // the multi-bitrate 10..1 padding rule, and permutes the state.
 func (d *state) padAndPermute() {
 	// Pad with this instance's domain-separator bits. We know that there's
-	// at least one byte of space in d.buf because, if it were full,
+	// at least one byte of space in the sponge because, if it were full,
 	// permute would have been called to empty it. dsbyte also contains the
 	// first one bit for the padding. See the comment in the state struct.
-	d.storage[d.n] = d.dsbyte
-	d.n++
-	for d.n < d.rate {
-		d.storage[d.n] = 0
-		d.n++
-	}
+	d.a[d.n] ^= d.dsbyte
 	// This adds the final one bit for the padding. Because of the way that
 	// bits are numbered from the LSB upwards, the final bit is the MSB of
 	// the last byte.
-	d.storage[d.rate-1] ^= 0x80
+	d.a[d.rate-1] ^= 0x80
 	// Apply the permutation
 	d.permute()
 	d.state = spongeSqueezing
-	d.n = d.rate
-	copyOut(d, d.storage[:d.rate])
 }
 
 // Write absorbs more data into the hash's state. It panics if any
 // output has already been read.
-func (d *state) Write(p []byte) (written int, err error) {
+func (d *state) Write(p []byte) (n int, err error) {
 	if d.state != spongeAbsorbing {
 		panic("sha3: Write after Read")
 	}
-	written = len(p)
+
+	n = len(p)
 
 	for len(p) > 0 {
-		if d.n == 0 && len(p) >= d.rate {
-			// The fast path; absorb a full "rate" bytes of input and apply the permutation.
-			xorIn(d, p[:d.rate])
-			p = p[d.rate:]
-			keccakF1600(&d.a)
-		} else {
-			// The slow path; buffer the input until we can fill the sponge, and then xor it in.
-			todo := d.rate - d.n
-			if todo > len(p) {
-				todo = len(p)
-			}
-			d.n += copy(d.storage[d.n:], p[:todo])
-			p = p[todo:]
+		x := subtle.XORBytes(d.a[d.n:d.rate], d.a[d.n:d.rate], p)
+		d.n += x
+		p = p[x:]
 
-			// If the sponge is full, apply the permutation.
-			if d.n == d.rate {
-				d.permute()
-			}
+		// If the sponge is full, apply the permutation.
+		if d.n == d.rate {
+			d.permute()
 		}
 	}
 
@@ -156,14 +144,14 @@ func (d *state) Read(out []byte) (n int, err error) {
 
 	// Now, do the squeezing.
 	for len(out) > 0 {
-		n := copy(out, d.storage[d.i:d.n])
-		d.i += n
-		out = out[n:]
-
 		// Apply the permutation if we've squeezed the sponge dry.
-		if d.i == d.rate {
+		if d.n == d.rate {
 			d.permute()
 		}
+
+		x := copy(out, d.a[d.n:d.rate])
+		d.n += x
+		out = out[x:]
 	}
 
 	return
@@ -183,3 +171,74 @@ func (d *state) Sum(in []byte) []byte {
 	dup.Read(hash)
 	return append(in, hash...)
 }
+
+const (
+	magicSHA3   = "sha\x08"
+	magicShake  = "sha\x09"
+	magicCShake = "sha\x0a"
+	magicKeccak = "sha\x0b"
+	// magic || rate || main state || n || sponge direction
+	marshaledSize = len(magicSHA3) + 1 + 200 + 1 + 1
+)
+
+func (d *state) MarshalBinary() ([]byte, error) {
+	return d.AppendBinary(make([]byte, 0, marshaledSize))
+}
+
+func (d *state) AppendBinary(b []byte) ([]byte, error) {
+	switch d.dsbyte {
+	case dsbyteSHA3:
+		b = append(b, magicSHA3...)
+	case dsbyteShake:
+		b = append(b, magicShake...)
+	case dsbyteCShake:
+		b = append(b, magicCShake...)
+	case dsbyteKeccak:
+		b = append(b, magicKeccak...)
+	default:
+		panic("unknown dsbyte")
+	}
+	// rate is at most 168, and n is at most rate.
+	b = append(b, byte(d.rate))
+	b = append(b, d.a[:]...)
+	b = append(b, byte(d.n), byte(d.state))
+	return b, nil
+}
+
+func (d *state) UnmarshalBinary(b []byte) error {
+	if len(b) != marshaledSize {
+		return errors.New("sha3: invalid hash state")
+	}
+
+	magic := string(b[:len(magicSHA3)])
+	b = b[len(magicSHA3):]
+	switch {
+	case magic == magicSHA3 && d.dsbyte == dsbyteSHA3:
+	case magic == magicShake && d.dsbyte == dsbyteShake:
+	case magic == magicCShake && d.dsbyte == dsbyteCShake:
+	case magic == magicKeccak && d.dsbyte == dsbyteKeccak:
+	default:
+		return errors.New("sha3: invalid hash state identifier")
+	}
+
+	rate := int(b[0])
+	b = b[1:]
+	if rate != d.rate {
+		return errors.New("sha3: invalid hash state function")
+	}
+
+	copy(d.a[:], b)
+	b = b[len(d.a):]
+
+	n, state := int(b[0]), spongeDirection(b[1])
+	if n > d.rate {
+		return errors.New("sha3: invalid hash state")
+	}
+	d.n = n
+	if state != spongeAbsorbing && state != spongeSqueezing {
+		return errors.New("sha3: invalid hash state")
+	}
+	d.state = state
+
+	return nil
+}

sha3/sha3_test.go

@@ -13,10 +13,12 @@ package sha3
 import (
 	"bytes"
 	"compress/flate"
+	"encoding"
 	"encoding/hex"
 	"encoding/json"
 	"fmt"
 	"hash"
+	"io"
 	"math/rand"
 	"os"
 	"strings"
@@ -375,6 +377,153 @@ func TestClone(t *testing.T) {
 	}
 }
 
+func TestCSHAKEAccumulated(t *testing.T) {
+	// Generated with pycryptodome@3.20.0
+	//
+	//    from Crypto.Hash import cSHAKE128
+	//    rng = cSHAKE128.new()
+	//    acc = cSHAKE128.new()
+	//    for n in range(200):
+	//        N = rng.read(n)
+	//        for s in range(200):
+	//            S = rng.read(s)
+	//            c = cSHAKE128.cSHAKE_XOF(data=None, custom=S, capacity=256, function=N)
+	//            c.update(rng.read(100))
+	//            acc.update(c.read(200))
+	//            c = cSHAKE128.cSHAKE_XOF(data=None, custom=S, capacity=256, function=N)
+	//            c.update(rng.read(168))
+	//            acc.update(c.read(200))
+	//            c = cSHAKE128.cSHAKE_XOF(data=None, custom=S, capacity=256, function=N)
+	//            c.update(rng.read(200))
+	//            acc.update(c.read(200))
+	//    print(acc.read(32).hex())
+	//
+	// and with @noble/hashes@v1.5.0
+	//
+	//    import { bytesToHex } from "@noble/hashes/utils";
+	//    import { cshake128 } from "@noble/hashes/sha3-addons";
+	//    const rng = cshake128.create();
+	//    const acc = cshake128.create();
+	//    for (let n = 0; n < 200; n++) {
+	//        const N = rng.xof(n);
+	//        for (let s = 0; s < 200; s++) {
+	//            const S = rng.xof(s);
+	//            let c = cshake128.create({ NISTfn: N, personalization: S });
+	//            c.update(rng.xof(100));
+	//            acc.update(c.xof(200));
+	//            c = cshake128.create({ NISTfn: N, personalization: S });
+	//            c.update(rng.xof(168));
+	//            acc.update(c.xof(200));
+	//            c = cshake128.create({ NISTfn: N, personalization: S });
+	//            c.update(rng.xof(200));
+	//            acc.update(c.xof(200));
+	//        }
+	//    }
+	//    console.log(bytesToHex(acc.xof(32)));
+	//
+	t.Run("cSHAKE128", func(t *testing.T) {
+		testCSHAKEAccumulated(t, NewCShake128, rateK256,
+			"bb14f8657c6ec5403d0b0e2ef3d3393497e9d3b1a9a9e8e6c81dbaa5fd809252")
+	})
+	t.Run("cSHAKE256", func(t *testing.T) {
+		testCSHAKEAccumulated(t, NewCShake256, rateK512,
+			"0baaf9250c6e25f0c14ea5c7f9bfde54c8a922c8276437db28f3895bdf6eeeef")
+	})
+}
+
+func testCSHAKEAccumulated(t *testing.T, newCShake func(N, S []byte) ShakeHash, rate int64, exp string) {
+	rnd := newCShake(nil, nil)
+	acc := newCShake(nil, nil)
+	for n := 0; n < 200; n++ {
+		N := make([]byte, n)
+		rnd.Read(N)
+		for s := 0; s < 200; s++ {
+			S := make([]byte, s)
+			rnd.Read(S)
+
+			c := newCShake(N, S)
+			io.CopyN(c, rnd, 100 /* < rate */)
+			io.CopyN(acc, c, 200)
+
+			c.Reset()
+			io.CopyN(c, rnd, rate)
+			io.CopyN(acc, c, 200)
+
+			c.Reset()
+			io.CopyN(c, rnd, 200 /* > rate */)
+			io.CopyN(acc, c, 200)
+		}
+	}
+	if got := hex.EncodeToString(acc.Sum(nil)[:32]); got != exp {
+		t.Errorf("got %s, want %s", got, exp)
+	}
+}
+
+func TestCSHAKELargeS(t *testing.T) {
+	if testing.Short() {
+		t.Skip("skipping test in short mode.")
+	}
+
+	// See https://go.dev/issue/66232.
+	const s = (1<<32)/8 + 1000 // s * 8 > 2^32
+	S := make([]byte, s)
+	rnd := NewShake128()
+	rnd.Read(S)
+	c := NewCShake128(nil, S)
+	io.CopyN(c, rnd, 1000)
+
+	// Generated with pycryptodome@3.20.0
+	//
+	//    from Crypto.Hash import cSHAKE128
+	//    rng = cSHAKE128.new()
+	//    S = rng.read(536871912)
+	//    c = cSHAKE128.new(custom=S)
+	//    c.update(rng.read(1000))
+	//    print(c.read(32).hex())
+	//
+	exp := "2cb9f237767e98f2614b8779cf096a52da9b3a849280bbddec820771ae529cf0"
+	if got := hex.EncodeToString(c.Sum(nil)); got != exp {
+		t.Errorf("got %s, want %s", got, exp)
+	}
+}
+
+func TestMarshalUnmarshal(t *testing.T) {
+	t.Run("SHA3-224", func(t *testing.T) { testMarshalUnmarshal(t, New224()) })
+	t.Run("SHA3-256", func(t *testing.T) { testMarshalUnmarshal(t, New256()) })
+	t.Run("SHA3-384", func(t *testing.T) { testMarshalUnmarshal(t, New384()) })
+	t.Run("SHA3-512", func(t *testing.T) { testMarshalUnmarshal(t, New512()) })
+	t.Run("SHAKE128", func(t *testing.T) { testMarshalUnmarshal(t, NewShake128()) })
+	t.Run("SHAKE256", func(t *testing.T) { testMarshalUnmarshal(t, NewShake256()) })
+	t.Run("cSHAKE128", func(t *testing.T) { testMarshalUnmarshal(t, NewCShake128([]byte("N"), []byte("S"))) })
+	t.Run("cSHAKE256", func(t *testing.T) { testMarshalUnmarshal(t, NewCShake256([]byte("N"), []byte("S"))) })
+	t.Run("Keccak-256", func(t *testing.T) { testMarshalUnmarshal(t, NewLegacyKeccak256()) })
+	t.Run("Keccak-512", func(t *testing.T) { testMarshalUnmarshal(t, NewLegacyKeccak512()) })
+}
+
+// TODO(filippo): move this to crypto/internal/cryptotest.
+func testMarshalUnmarshal(t *testing.T, h hash.Hash) {
+	buf := make([]byte, 200)
+	rand.Read(buf)
+	n := rand.Intn(200)
+	h.Write(buf)
+	want := h.Sum(nil)
+	h.Reset()
+	h.Write(buf[:n])
+	b, err := h.(encoding.BinaryMarshaler).MarshalBinary()
+	if err != nil {
+		t.Errorf("MarshalBinary: %v", err)
+	}
+	h.Write(bytes.Repeat([]byte{0}, 200))
+	if err := h.(encoding.BinaryUnmarshaler).UnmarshalBinary(b); err != nil {
+		t.Errorf("UnmarshalBinary: %v", err)
+	}
+	h.Write(buf[n:])
+	got := h.Sum(nil)
+	if !bytes.Equal(got, want) {
+		t.Errorf("got %x, want %x", got, want)
+	}
+}
+
 // BenchmarkPermutationFunction measures the speed of the permutation function
 // with no input data.
 func BenchmarkPermutationFunction(b *testing.B) {

sha3/shake.go

@@ -16,9 +16,12 @@ package sha3
 // [2] https://doi.org/10.6028/NIST.SP.800-185
 
 import (
+	"bytes"
 	"encoding/binary"
+	"errors"
 	"hash"
 	"io"
+	"math/bits"
 )
 
 // ShakeHash defines the interface to hash functions that support
@@ -50,44 +53,36 @@ type cshakeState struct {
 	initBlock []byte
 }
 
-// Consts for configuring initial SHA-3 state
-const (
-	dsbyteShake  = 0x1f
-	dsbyteCShake = 0x04
-	rate128      = 168
-	rate256      = 136
-)
-
-func bytepad(input []byte, w int) []byte {
-	// leftEncode always returns max 9 bytes
-	buf := make([]byte, 0, 9+len(input)+w)
-	buf = append(buf, leftEncode(uint64(w))...)
-	buf = append(buf, input...)
-	padlen := w - (len(buf) % w)
-	return append(buf, make([]byte, padlen)...)
+func bytepad(data []byte, rate int) []byte {
+	out := make([]byte, 0, 9+len(data)+rate-1)
+	out = append(out, leftEncode(uint64(rate))...)
+	out = append(out, data...)
+	if padlen := rate - len(out)%rate; padlen < rate {
+		out = append(out, make([]byte, padlen)...)
+	}
+	return out
 }
 
-func leftEncode(value uint64) []byte {
-	var b [9]byte
-	binary.BigEndian.PutUint64(b[1:], value)
-	// Trim all but last leading zero bytes
-	i := byte(1)
-	for i < 8 && b[i] == 0 {
-		i++
+func leftEncode(x uint64) []byte {
+	// Let n be the smallest positive integer for which 2^(8n) > x.
+	n := (bits.Len64(x) + 7) / 8
+	if n == 0 {
+		n = 1
 	}
-	// Prepend number of encoded bytes
-	b[i-1] = 9 - i
-	return b[i-1:]
+	// Return n || x with n as a byte and x an n bytes in big-endian order.
+	b := make([]byte, 9)
+	binary.BigEndian.PutUint64(b[1:], x)
+	b = b[9-n-1:]
+	b[0] = byte(n)
+	return b
 }
 
 func newCShake(N, S []byte, rate, outputLen int, dsbyte byte) ShakeHash {
 	c := cshakeState{state: &state{rate: rate, outputLen: outputLen, dsbyte: dsbyte}}
-
-	// leftEncode returns max 9 bytes
-	c.initBlock = make([]byte, 0, 9*2+len(N)+len(S))
-	c.initBlock = append(c.initBlock, leftEncode(uint64(len(N)*8))...)
+	c.initBlock = make([]byte, 0, 9+len(N)+9+len(S)) // leftEncode returns max 9 bytes
+	c.initBlock = append(c.initBlock, leftEncode(uint64(len(N))*8)...)
 	c.initBlock = append(c.initBlock, N...)
-	c.initBlock = append(c.initBlock, leftEncode(uint64(len(S)*8))...)
+	c.initBlock = append(c.initBlock, leftEncode(uint64(len(S))*8)...)
 	c.initBlock = append(c.initBlock, S...)
 	c.Write(bytepad(c.initBlock, c.rate))
 	return &c
@@ -111,6 +106,30 @@ func (c *state) Clone() ShakeHash {
 	return c.clone()
 }
 
+func (c *cshakeState) MarshalBinary() ([]byte, error) {
+	return c.AppendBinary(make([]byte, 0, marshaledSize+len(c.initBlock)))
+}
+
+func (c *cshakeState) AppendBinary(b []byte) ([]byte, error) {
+	b, err := c.state.AppendBinary(b)
+	if err != nil {
+		return nil, err
+	}
+	b = append(b, c.initBlock...)
+	return b, nil
+}
+
+func (c *cshakeState) UnmarshalBinary(b []byte) error {
+	if len(b) <= marshaledSize {
+		return errors.New("sha3: invalid hash state")
+	}
+	if err := c.state.UnmarshalBinary(b[:marshaledSize]); err != nil {
+		return err
+	}
+	c.initBlock = bytes.Clone(b[marshaledSize:])
+	return nil
+}
+
 // NewShake128 creates a new SHAKE128 variable-output-length ShakeHash.
 // Its generic security strength is 128 bits against all attacks if at
 // least 32 bytes of its output are used.
@@ -126,11 +145,11 @@ func NewShake256() ShakeHash {
 }
 
 func newShake128Generic() *state {
-	return &state{rate: rate128, outputLen: 32, dsbyte: dsbyteShake}
+	return &state{rate: rateK256, outputLen: 32, dsbyte: dsbyteShake}
 }
 
 func newShake256Generic() *state {
-	return &state{rate: rate256, outputLen: 64, dsbyte: dsbyteShake}
+	return &state{rate: rateK512, outputLen: 64, dsbyte: dsbyteShake}
 }
 
 // NewCShake128 creates a new instance of cSHAKE128 variable-output-length ShakeHash,
@@ -143,7 +162,7 @@ func NewCShake128(N, S []byte) ShakeHash {
 	if len(N) == 0 && len(S) == 0 {
 		return NewShake128()
 	}
-	return newCShake(N, S, rate128, 32, dsbyteCShake)
+	return newCShake(N, S, rateK256, 32, dsbyteCShake)
 }
 
 // NewCShake256 creates a new instance of cSHAKE256 variable-output-length ShakeHash,
@@ -156,7 +175,7 @@ func NewCShake256(N, S []byte) ShakeHash {
 	if len(N) == 0 && len(S) == 0 {
 		return NewShake256()
 	}
-	return newCShake(N, S, rate256, 64, dsbyteCShake)
+	return newCShake(N, S, rateK512, 64, dsbyteCShake)
 }
 
 // ShakeSum128 writes an arbitrary-length digest of data into hash.

sha3/xor.go

@@ -1,40 +0,0 @@
-// Copyright 2015 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package sha3
-
-import (
-	"crypto/subtle"
-	"encoding/binary"
-	"unsafe"
-
-	"golang.org/x/sys/cpu"
-)
-
-// xorIn xors the bytes in buf into the state.
-func xorIn(d *state, buf []byte) {
-	if cpu.IsBigEndian {
-		for i := 0; len(buf) >= 8; i++ {
-			a := binary.LittleEndian.Uint64(buf)
-			d.a[i] ^= a
-			buf = buf[8:]
-		}
-	} else {
-		ab := (*[25 * 64 / 8]byte)(unsafe.Pointer(&d.a))
-		subtle.XORBytes(ab[:], ab[:], buf)
-	}
-}
-
-// copyOut copies uint64s to a byte buffer.
-func copyOut(d *state, b []byte) {
-	if cpu.IsBigEndian {
-		for i := 0; len(b) >= 8; i++ {
-			binary.LittleEndian.PutUint64(b, d.a[i])
-			b = b[8:]
-		}
-	} else {
-		ab := (*[25 * 64 / 8]byte)(unsafe.Pointer(&d.a))
-		copy(b, ab[:])
-	}
-}

ssh/agent/client.go

@@ -555,7 +555,7 @@ func (c *client) insertKey(s interface{}, comment string, constraints []byte) er
 		})
 	case *dsa.PrivateKey:
 		req = ssh.Marshal(dsaKeyMsg{
-			Type:        ssh.KeyAlgoDSA,
+			Type:        ssh.InsecureKeyAlgoDSA,
 			P:           k.P,
 			Q:           k.Q,
 			G:           k.G,
@@ -803,16 +803,16 @@ var _ ssh.AlgorithmSigner = &agentKeyringSigner{}
 //
 // This map must be kept in sync with the one in certs.go.
 var certKeyAlgoNames = map[string]string{
-	ssh.CertAlgoRSAv01:        ssh.KeyAlgoRSA,
-	ssh.CertAlgoRSASHA256v01:  ssh.KeyAlgoRSASHA256,
-	ssh.CertAlgoRSASHA512v01:  ssh.KeyAlgoRSASHA512,
-	ssh.CertAlgoDSAv01:        ssh.KeyAlgoDSA,
-	ssh.CertAlgoECDSA256v01:   ssh.KeyAlgoECDSA256,
-	ssh.CertAlgoECDSA384v01:   ssh.KeyAlgoECDSA384,
-	ssh.CertAlgoECDSA521v01:   ssh.KeyAlgoECDSA521,
-	ssh.CertAlgoSKECDSA256v01: ssh.KeyAlgoSKECDSA256,
-	ssh.CertAlgoED25519v01:    ssh.KeyAlgoED25519,
-	ssh.CertAlgoSKED25519v01:  ssh.KeyAlgoSKED25519,
+	ssh.CertAlgoRSAv01:         ssh.KeyAlgoRSA,
+	ssh.CertAlgoRSASHA256v01:   ssh.KeyAlgoRSASHA256,
+	ssh.CertAlgoRSASHA512v01:   ssh.KeyAlgoRSASHA512,
+	ssh.InsecureCertAlgoDSAv01: ssh.InsecureKeyAlgoDSA,
+	ssh.CertAlgoECDSA256v01:    ssh.KeyAlgoECDSA256,
+	ssh.CertAlgoECDSA384v01:    ssh.KeyAlgoECDSA384,
+	ssh.CertAlgoECDSA521v01:    ssh.KeyAlgoECDSA521,
+	ssh.CertAlgoSKECDSA256v01:  ssh.KeyAlgoSKECDSA256,
+	ssh.CertAlgoED25519v01:     ssh.KeyAlgoED25519,
+	ssh.CertAlgoSKED25519v01:   ssh.KeyAlgoSKED25519,
 }
 
 // underlyingAlgo returns the signature algorithm associated with algo (which is

ssh/agent/keyring.go

@@ -175,6 +175,15 @@ func (r *keyring) Add(key AddedKey) error {
 		p.expire = &t
 	}
 
+	// If we already have a Signer with the same public key, replace it with the
+	// new one.
+	for idx, k := range r.keys {
+		if bytes.Equal(k.signer.PublicKey().Marshal(), p.signer.PublicKey().Marshal()) {
+			r.keys[idx] = p
+			return nil
+		}
+	}
+
 	r.keys = append(r.keys, p)
 
 	return nil

ssh/agent/keyring_test.go

@@ -29,6 +29,10 @@ func validateListedKeys(t *testing.T, a Agent, expectedKeys []string) {
 		t.Fatalf("failed to list keys: %v", err)
 		return
 	}
+	if len(listedKeys) != len(expectedKeys) {
+		t.Fatalf("expeted %d key, got %d", len(expectedKeys), len(listedKeys))
+		return
+	}
 	actualKeys := make(map[string]bool)
 	for _, key := range listedKeys {
 		actualKeys[key.Comment] = true
@@ -74,3 +78,45 @@ func TestKeyringAddingAndRemoving(t *testing.T) {
 	}
 	validateListedKeys(t, k, []string{})
 }
+
+func TestAddDuplicateKey(t *testing.T) {
+	keyNames := []string{"rsa", "user"}
+
+	k := NewKeyring()
+	for _, keyName := range keyNames {
+		addTestKey(t, k, keyName)
+	}
+	validateListedKeys(t, k, keyNames)
+	// Add the keys again.
+	for _, keyName := range keyNames {
+		addTestKey(t, k, keyName)
+	}
+	validateListedKeys(t, k, keyNames)
+	// Add an existing key with an updated comment.
+	keyName := keyNames[0]
+	addedKey := AddedKey{
+		PrivateKey: testPrivateKeys[keyName],
+		Comment:    "comment updated",
+	}
+	err := k.Add(addedKey)
+	if err != nil {
+		t.Fatalf("failed to add key %q: %v", keyName, err)
+	}
+	// Check the that key is found and the comment was updated.
+	keys, err := k.List()
+	if err != nil {
+		t.Fatalf("failed to list keys: %v", err)
+	}
+	if len(keys) != len(keyNames) {
+		t.Fatalf("expected %d keys, got %d", len(keyNames), len(keys))
+	}
+	isFound := false
+	for _, key := range keys {
+		if key.Comment == addedKey.Comment {
+			isFound = true
+		}
+	}
+	if !isFound {
+		t.Fatal("key with the updated comment not found")
+	}
+}

ssh/agent/server.go

@@ -506,7 +506,7 @@ func (s *server) insertIdentity(req []byte) error {
 	switch record.Type {
 	case ssh.KeyAlgoRSA:
 		addedKey, err = parseRSAKey(req)
-	case ssh.KeyAlgoDSA:
+	case ssh.InsecureKeyAlgoDSA:
 		addedKey, err = parseDSAKey(req)
 	case ssh.KeyAlgoECDSA256, ssh.KeyAlgoECDSA384, ssh.KeyAlgoECDSA521:
 		addedKey, err = parseECDSAKey(req)
@@ -514,7 +514,7 @@ func (s *server) insertIdentity(req []byte) error {
 		addedKey, err = parseEd25519Key(req)
 	case ssh.CertAlgoRSAv01:
 		addedKey, err = parseRSACert(req)
-	case ssh.CertAlgoDSAv01:
+	case ssh.InsecureCertAlgoDSAv01:
 		addedKey, err = parseDSACert(req)
 	case ssh.CertAlgoECDSA256v01, ssh.CertAlgoECDSA384v01, ssh.CertAlgoECDSA521v01:
 		addedKey, err = parseECDSACert(req)

ssh/certs.go

@@ -20,14 +20,19 @@ import (
 // returned by MultiAlgorithmSigner and don't appear in the Signature.Format
 // field.
 const (
-	CertAlgoRSAv01        = "ssh-rsa-cert-v01@openssh.com"
-	CertAlgoDSAv01        = "ssh-dss-cert-v01@openssh.com"
-	CertAlgoECDSA256v01   = "ecdsa-sha2-nistp256-cert-v01@openssh.com"
-	CertAlgoECDSA384v01   = "ecdsa-sha2-nistp384-cert-v01@openssh.com"
-	CertAlgoECDSA521v01   = "ecdsa-sha2-nistp521-cert-v01@openssh.com"
-	CertAlgoSKECDSA256v01 = "sk-ecdsa-sha2-nistp256-cert-v01@openssh.com"
-	CertAlgoED25519v01    = "ssh-ed25519-cert-v01@openssh.com"
-	CertAlgoSKED25519v01  = "sk-ssh-ed25519-cert-v01@openssh.com"
+	CertAlgoRSAv01 = "ssh-rsa-cert-v01@openssh.com"
+	// Deprecated: DSA is only supported at insecure key sizes, and was removed
+	// from major implementations.
+	CertAlgoDSAv01 = InsecureCertAlgoDSAv01
+	// Deprecated: DSA is only supported at insecure key sizes, and was removed
+	// from major implementations.
+	InsecureCertAlgoDSAv01 = "ssh-dss-cert-v01@openssh.com"
+	CertAlgoECDSA256v01    = "ecdsa-sha2-nistp256-cert-v01@openssh.com"
+	CertAlgoECDSA384v01    = "ecdsa-sha2-nistp384-cert-v01@openssh.com"
+	CertAlgoECDSA521v01    = "ecdsa-sha2-nistp521-cert-v01@openssh.com"
+	CertAlgoSKECDSA256v01  = "sk-ecdsa-sha2-nistp256-cert-v01@openssh.com"
+	CertAlgoED25519v01     = "ssh-ed25519-cert-v01@openssh.com"
+	CertAlgoSKED25519v01   = "sk-ssh-ed25519-cert-v01@openssh.com"
 
 	// CertAlgoRSASHA256v01 and CertAlgoRSASHA512v01 can't appear as a
 	// Certificate.Type (or PublicKey.Type), but only in
@@ -228,7 +233,11 @@ func parseCert(in []byte, privAlgo string) (*Certificate, error) {
 	if err != nil {
 		return nil, err
 	}
-
+	// The Type() function is intended to return only certificate key types, but
+	// we use certKeyAlgoNames anyway for safety, to match [Certificate.Type].
+	if _, ok := certKeyAlgoNames[k.Type()]; ok {
+		return nil, fmt.Errorf("ssh: the signature key type %q is invalid for certificates", k.Type())
+	}
 	c.SignatureKey = k
 	c.Signature, rest, ok = parseSignatureBody(g.Signature)
 	if !ok || len(rest) > 0 {
@@ -296,16 +305,13 @@ type CertChecker struct {
 	SupportedCriticalOptions []string
 
 	// IsUserAuthority should return true if the key is recognized as an
-	// authority for the given user certificate. This allows for
-	// certificates to be signed by other certificates. This must be set
-	// if this CertChecker will be checking user certificates.
+	// authority for user certificate. This must be set if this CertChecker
+	// will be checking user certificates.
 	IsUserAuthority func(auth PublicKey) bool
 
 	// IsHostAuthority should report whether the key is recognized as
-	// an authority for this host. This allows for certificates to be
-	// signed by other keys, and for those other keys to only be valid
-	// signers for particular hostnames. This must be set if this
-	// CertChecker will be checking host certificates.
+	// an authority for this host. This must be set if this CertChecker
+	// will be checking host certificates.
 	IsHostAuthority func(auth PublicKey, address string) bool
 
 	// Clock is used for verifying time stamps. If nil, time.Now
@@ -442,12 +448,19 @@ func (c *CertChecker) CheckCert(principal string, cert *Certificate) error {
 // SignCert signs the certificate with an authority, setting the Nonce,
 // SignatureKey, and Signature fields. If the authority implements the
 // MultiAlgorithmSigner interface the first algorithm in the list is used. This
-// is useful if you want to sign with a specific algorithm.
+// is useful if you want to sign with a specific algorithm. As specified in
+// [SSH-CERTS], Section 2.1.1, authority can't be a [Certificate].
 func (c *Certificate) SignCert(rand io.Reader, authority Signer) error {
 	c.Nonce = make([]byte, 32)
 	if _, err := io.ReadFull(rand, c.Nonce); err != nil {
 		return err
 	}
+	// The Type() function is intended to return only certificate key types, but
+	// we use certKeyAlgoNames anyway for safety, to match [Certificate.Type].
+	if _, ok := certKeyAlgoNames[authority.PublicKey().Type()]; ok {
+		return fmt.Errorf("ssh: certificates cannot be used as authority (public key type %q)",
+			authority.PublicKey().Type())
+	}
 	c.SignatureKey = authority.PublicKey()
 
 	if v, ok := authority.(MultiAlgorithmSigner); ok {
@@ -485,16 +498,16 @@ func (c *Certificate) SignCert(rand io.Reader, authority Signer) error {
 //
 // This map must be kept in sync with the one in agent/client.go.
 var certKeyAlgoNames = map[string]string{
-	CertAlgoRSAv01:        KeyAlgoRSA,
-	CertAlgoRSASHA256v01:  KeyAlgoRSASHA256,
-	CertAlgoRSASHA512v01:  KeyAlgoRSASHA512,
-	CertAlgoDSAv01:        KeyAlgoDSA,
-	CertAlgoECDSA256v01:   KeyAlgoECDSA256,
-	CertAlgoECDSA384v01:   KeyAlgoECDSA384,
-	CertAlgoECDSA521v01:   KeyAlgoECDSA521,
-	CertAlgoSKECDSA256v01: KeyAlgoSKECDSA256,
-	CertAlgoED25519v01:    KeyAlgoED25519,
-	CertAlgoSKED25519v01:  KeyAlgoSKED25519,
+	CertAlgoRSAv01:         KeyAlgoRSA,
+	CertAlgoRSASHA256v01:   KeyAlgoRSASHA256,
+	CertAlgoRSASHA512v01:   KeyAlgoRSASHA512,
+	InsecureCertAlgoDSAv01: InsecureKeyAlgoDSA,
+	CertAlgoECDSA256v01:    KeyAlgoECDSA256,
+	CertAlgoECDSA384v01:    KeyAlgoECDSA384,
+	CertAlgoECDSA521v01:    KeyAlgoECDSA521,
+	CertAlgoSKECDSA256v01:  KeyAlgoSKECDSA256,
+	CertAlgoED25519v01:     KeyAlgoED25519,
+	CertAlgoSKED25519v01:   KeyAlgoSKED25519,
 }
 
 // underlyingAlgo returns the signature algorithm associated with algo (which is

ssh/certs_test.go

@@ -15,14 +15,12 @@ import (
 	"reflect"
 	"testing"
 	"time"
+
+	"golang.org/x/crypto/ssh/testdata"
 )
 
-// Cert generated by ssh-keygen 6.0p1 Debian-4.
-// % ssh-keygen -s ca-key -I test user-key
-const exampleSSHCert = `ssh-rsa-cert-v01@openssh.com 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`
-
 func TestParseCert(t *testing.T) {
-	authKeyBytes := []byte(exampleSSHCert)
+	authKeyBytes := bytes.TrimSuffix(testdata.SSHCertificates["rsa"], []byte(" host.example.com\n"))
 
 	key, _, _, rest, err := ParseAuthorizedKey(authKeyBytes)
 	if err != nil {
@@ -103,7 +101,7 @@ func TestParseCertWithOptions(t *testing.T) {
 }
 
 func TestValidateCert(t *testing.T) {
-	key, _, _, _, err := ParseAuthorizedKey([]byte(exampleSSHCert))
+	key, _, _, _, err := ParseAuthorizedKey(testdata.SSHCertificates["rsa-user-testcertificate"])
 	if err != nil {
 		t.Fatalf("ParseAuthorizedKey: %v", err)
 	}
@@ -116,7 +114,7 @@ func TestValidateCert(t *testing.T) {
 		return bytes.Equal(k.Marshal(), validCert.SignatureKey.Marshal())
 	}
 
-	if err := checker.CheckCert("user", validCert); err != nil {
+	if err := checker.CheckCert("testcertificate", validCert); err != nil {
 		t.Errorf("Unable to validate certificate: %v", err)
 	}
 	invalidCert := &Certificate{
@@ -125,7 +123,7 @@ func TestValidateCert(t *testing.T) {
 		ValidBefore:  CertTimeInfinity,
 		Signature:    &Signature{},
 	}
-	if err := checker.CheckCert("user", invalidCert); err == nil {
+	if err := checker.CheckCert("testcertificate", invalidCert); err == nil {
 		t.Error("Invalid cert signature passed validation")
 	}
 }
@@ -299,7 +297,7 @@ func TestCertTypes(t *testing.T) {
 		{"legacyRSASigner", &legacyRSASigner{testSigners["rsa"]}, KeyAlgoRSA},
 		{"multiAlgoRSASignerSHA256", multiAlgoSignerSHA256, KeyAlgoRSASHA256},
 		{"multiAlgoRSASignerSHA512", multiAlgoSignerSHA512, KeyAlgoRSASHA512},
-		{CertAlgoDSAv01, testSigners["dsa"], ""},
+		{InsecureCertAlgoDSAv01, testSigners["dsa"], ""},
 	}
 
 	k, err := ecdsa.GenerateKey(elliptic.P256(), rand.Reader)
@@ -406,3 +404,32 @@ func TestCertSignWithMultiAlgorithmSigner(t *testing.T) {
 		})
 	}
 }
+
+func TestCertSignWithCertificate(t *testing.T) {
+	cert := &Certificate{
+		Key:         testPublicKeys["rsa"],
+		ValidBefore: CertTimeInfinity,
+		CertType:    UserCert,
+	}
+	if err := cert.SignCert(rand.Reader, testSigners["ecdsa"]); err != nil {
+		t.Fatalf("SignCert: %v", err)
+	}
+	signer, err := NewSignerWithAlgorithms(testSigners["rsa"].(AlgorithmSigner), []string{KeyAlgoRSASHA256})
+	if err != nil {
+		t.Fatal(err)
+	}
+	certSigner, err := NewCertSigner(cert, signer)
+	if err != nil {
+		t.Fatalf("NewCertSigner: %v", err)
+	}
+
+	cert1 := &Certificate{
+		Key:         testPublicKeys["ecdsa"],
+		ValidBefore: CertTimeInfinity,
+		CertType:    UserCert,
+	}
+
+	if err := cert1.SignCert(rand.Reader, certSigner); err == nil {
+		t.Fatal("successfully signed a certificate using another certificate, it is expected to fail")
+	}
+}

ssh/cipher.go

@@ -58,11 +58,11 @@ func newRC4(key, iv []byte) (cipher.Stream, error) {
 type cipherMode struct {
 	keySize int
 	ivSize  int
-	create  func(key, iv []byte, macKey []byte, algs directionAlgorithms) (packetCipher, error)
+	create  func(key, iv []byte, macKey []byte, algs DirectionAlgorithms) (packetCipher, error)
 }
 
-func streamCipherMode(skip int, createFunc func(key, iv []byte) (cipher.Stream, error)) func(key, iv []byte, macKey []byte, algs directionAlgorithms) (packetCipher, error) {
-	return func(key, iv, macKey []byte, algs directionAlgorithms) (packetCipher, error) {
+func streamCipherMode(skip int, createFunc func(key, iv []byte) (cipher.Stream, error)) func(key, iv []byte, macKey []byte, algs DirectionAlgorithms) (packetCipher, error) {
+	return func(key, iv, macKey []byte, algs DirectionAlgorithms) (packetCipher, error) {
 		stream, err := createFunc(key, iv)
 		if err != nil {
 			return nil, err
@@ -98,36 +98,36 @@ func streamCipherMode(skip int, createFunc func(key, iv []byte) (cipher.Stream,
 var cipherModes = map[string]*cipherMode{
 	// Ciphers from RFC 4344, which introduced many CTR-based ciphers. Algorithms
 	// are defined in the order specified in the RFC.
-	"aes128-ctr": {16, aes.BlockSize, streamCipherMode(0, newAESCTR)},
-	"aes192-ctr": {24, aes.BlockSize, streamCipherMode(0, newAESCTR)},
-	"aes256-ctr": {32, aes.BlockSize, streamCipherMode(0, newAESCTR)},
+	CipherAES128CTR: {16, aes.BlockSize, streamCipherMode(0, newAESCTR)},
+	CipherAES192CTR: {24, aes.BlockSize, streamCipherMode(0, newAESCTR)},
+	CipherAES256CTR: {32, aes.BlockSize, streamCipherMode(0, newAESCTR)},
 
 	// Ciphers from RFC 4345, which introduces security-improved arcfour ciphers.
 	// They are defined in the order specified in the RFC.
-	"arcfour128": {16, 0, streamCipherMode(1536, newRC4)},
-	"arcfour256": {32, 0, streamCipherMode(1536, newRC4)},
+	InsecureCipherRC4128: {16, 0, streamCipherMode(1536, newRC4)},
+	InsecureCipherRC4256: {32, 0, streamCipherMode(1536, newRC4)},
 
 	// Cipher defined in RFC 4253, which describes SSH Transport Layer Protocol.
 	// Note that this cipher is not safe, as stated in RFC 4253: "Arcfour (and
 	// RC4) has problems with weak keys, and should be used with caution."
 	// RFC 4345 introduces improved versions of Arcfour.
-	"arcfour": {16, 0, streamCipherMode(0, newRC4)},
+	InsecureCipherRC4: {16, 0, streamCipherMode(0, newRC4)},
 
 	// AEAD ciphers
-	gcm128CipherID:     {16, 12, newGCMCipher},
-	gcm256CipherID:     {32, 12, newGCMCipher},
-	chacha20Poly1305ID: {64, 0, newChaCha20Cipher},
+	CipherAES128GCM:        {16, 12, newGCMCipher},
+	CipherAES256GCM:        {32, 12, newGCMCipher},
+	CipherChaCha20Poly1305: {64, 0, newChaCha20Cipher},
 
 	// CBC mode is insecure and so is not included in the default config.
 	// (See https://www.ieee-security.org/TC/SP2013/papers/4977a526.pdf). If absolutely
 	// needed, it's possible to specify a custom Config to enable it.
 	// You should expect that an active attacker can recover plaintext if
 	// you do.
-	aes128cbcID: {16, aes.BlockSize, newAESCBCCipher},
+	InsecureCipherAES128CBC: {16, aes.BlockSize, newAESCBCCipher},
 
 	// 3des-cbc is insecure and is not included in the default
 	// config.
-	tripledescbcID: {24, des.BlockSize, newTripleDESCBCCipher},
+	InsecureCipherTripleDESCBC: {24, des.BlockSize, newTripleDESCBCCipher},
 }
 
 // prefixLen is the length of the packet prefix that contains the packet length
@@ -307,7 +307,7 @@ type gcmCipher struct {
 	buf    []byte
 }
 
-func newGCMCipher(key, iv, unusedMacKey []byte, unusedAlgs directionAlgorithms) (packetCipher, error) {
+func newGCMCipher(key, iv, unusedMacKey []byte, unusedAlgs DirectionAlgorithms) (packetCipher, error) {
 	c, err := aes.NewCipher(key)
 	if err != nil {
 		return nil, err
@@ -429,7 +429,7 @@ type cbcCipher struct {
 	oracleCamouflage uint32
 }
 
-func newCBCCipher(c cipher.Block, key, iv, macKey []byte, algs directionAlgorithms) (packetCipher, error) {
+func newCBCCipher(c cipher.Block, key, iv, macKey []byte, algs DirectionAlgorithms) (packetCipher, error) {
 	cbc := &cbcCipher{
 		mac:        macModes[algs.MAC].new(macKey),
 		decrypter:  cipher.NewCBCDecrypter(c, iv),
@@ -443,7 +443,7 @@ func newCBCCipher(c cipher.Block, key, iv, macKey []byte, algs directionAlgorith
 	return cbc, nil
 }
 
-func newAESCBCCipher(key, iv, macKey []byte, algs directionAlgorithms) (packetCipher, error) {
+func newAESCBCCipher(key, iv, macKey []byte, algs DirectionAlgorithms) (packetCipher, error) {
 	c, err := aes.NewCipher(key)
 	if err != nil {
 		return nil, err
@@ -457,7 +457,7 @@ func newAESCBCCipher(key, iv, macKey []byte, algs directionAlgorithms) (packetCi
 	return cbc, nil
 }
 
-func newTripleDESCBCCipher(key, iv, macKey []byte, algs directionAlgorithms) (packetCipher, error) {
+func newTripleDESCBCCipher(key, iv, macKey []byte, algs DirectionAlgorithms) (packetCipher, error) {
 	c, err := des.NewTripleDESCipher(key)
 	if err != nil {
 		return nil, err
@@ -635,8 +635,6 @@ func (c *cbcCipher) writeCipherPacket(seqNum uint32, w io.Writer, rand io.Reader
 	return nil
 }
 
-const chacha20Poly1305ID = "chacha20-poly1305@openssh.com"
-
 // chacha20Poly1305Cipher implements the chacha20-poly1305@openssh.com
 // AEAD, which is described here:
 //
@@ -650,7 +648,7 @@ type chacha20Poly1305Cipher struct {
 	buf        []byte
 }
 
-func newChaCha20Cipher(key, unusedIV, unusedMACKey []byte, unusedAlgs directionAlgorithms) (packetCipher, error) {
+func newChaCha20Cipher(key, unusedIV, unusedMACKey []byte, unusedAlgs DirectionAlgorithms) (packetCipher, error) {
 	if len(key) != 64 {
 		panic(len(key))
 	}

ssh/cipher_test.go

@@ -22,7 +22,7 @@ func TestDefaultCiphersExist(t *testing.T) {
 			t.Errorf("supported cipher %q is unknown", cipherAlgo)
 		}
 	}
-	for _, cipherAlgo := range preferredCiphers {
+	for _, cipherAlgo := range defaultCiphers {
 		if _, ok := cipherModes[cipherAlgo]; !ok {
 			t.Errorf("preferred cipher %q is unknown", cipherAlgo)
 		}
@@ -30,8 +30,8 @@ func TestDefaultCiphersExist(t *testing.T) {
 }
 
 func TestPacketCiphers(t *testing.T) {
-	defaultMac := "hmac-sha2-256"
-	defaultCipher := "aes128-ctr"
+	defaultMac := HMACSHA256
+	defaultCipher := CipherAES128CTR
 	for cipher := range cipherModes {
 		t.Run("cipher="+cipher,
 			func(t *testing.T) { testPacketCipher(t, cipher, defaultMac) })
@@ -44,10 +44,10 @@ func TestPacketCiphers(t *testing.T) {
 
 func testPacketCipher(t *testing.T, cipher, mac string) {
 	kr := &kexResult{Hash: crypto.SHA1}
-	algs := directionAlgorithms{
+	algs := DirectionAlgorithms{
 		Cipher:      cipher,
 		MAC:         mac,
-		Compression: "none",
+		compression: compressionNone,
 	}
 	client, err := newPacketCipher(clientKeys, algs, kr)
 	if err != nil {
@@ -77,10 +77,10 @@ func testPacketCipher(t *testing.T, cipher, mac string) {
 
 func TestCBCOracleCounterMeasure(t *testing.T) {
 	kr := &kexResult{Hash: crypto.SHA1}
-	algs := directionAlgorithms{
-		Cipher:      aes128cbcID,
-		MAC:         "hmac-sha1",
-		Compression: "none",
+	algs := DirectionAlgorithms{
+		Cipher:      InsecureCipherAES128CBC,
+		MAC:         HMACSHA1,
+		compression: compressionNone,
 	}
 	client, err := newPacketCipher(clientKeys, algs, kr)
 	if err != nil {
@@ -141,7 +141,7 @@ func TestCVE202143565(t *testing.T) {
 		constructPacket func(packetCipher) io.Reader
 	}{
 		{
-			cipher: gcm128CipherID,
+			cipher: CipherAES128GCM,
 			constructPacket: func(client packetCipher) io.Reader {
 				internalCipher := client.(*gcmCipher)
 				b := &bytes.Buffer{}
@@ -159,7 +159,7 @@ func TestCVE202143565(t *testing.T) {
 			},
 		},
 		{
-			cipher: chacha20Poly1305ID,
+			cipher: CipherChaCha20Poly1305,
 			constructPacket: func(client packetCipher) io.Reader {
 				internalCipher := client.(*chacha20Poly1305Cipher)
 				b := &bytes.Buffer{}
@@ -201,13 +201,13 @@ func TestCVE202143565(t *testing.T) {
 	}
 
 	for _, tc := range tests {
-		mac := "hmac-sha2-256"
+		mac := HMACSHA256
 
 		kr := &kexResult{Hash: crypto.SHA1}
-		algs := directionAlgorithms{
+		algs := DirectionAlgorithms{
 			Cipher:      tc.cipher,
 			MAC:         mac,
-			Compression: "none",
+			compression: compressionNone,
 		}
 		client, err := newPacketCipher(clientKeys, algs, kr)
 		if err != nil {

ssh/client.go

@@ -110,6 +110,7 @@ func (c *connection) clientHandshake(dialAddress string, config *ClientConfig) e
 	}
 
 	c.sessionID = c.transport.getSessionID()
+	c.algorithms = c.transport.getAlgorithms()
 	return c.clientAuthenticate(config)
 }
 

ssh/client_auth.go

@@ -289,7 +289,7 @@ func pickSignatureAlgorithm(signer Signer, extensions map[string][]byte) (MultiA
 		}
 	}
 
-	algo, err := findCommon("public key signature algorithm", keyAlgos, serverAlgos)
+	algo, err := findCommon("public key signature algorithm", keyAlgos, serverAlgos, true)
 	if err != nil {
 		// If there is no overlap, return the fallback algorithm to support
 		// servers that fail to list all supported algorithms.
@@ -555,6 +555,7 @@ func (cb KeyboardInteractiveChallenge) auth(session []byte, user string, c packe
 	}
 
 	gotMsgExtInfo := false
+	gotUserAuthInfoRequest := false
 	for {
 		packet, err := c.readPacket()
 		if err != nil {
@@ -585,6 +586,9 @@ func (cb KeyboardInteractiveChallenge) auth(session []byte, user string, c packe
 			if msg.PartialSuccess {
 				return authPartialSuccess, msg.Methods, nil
 			}
+			if !gotUserAuthInfoRequest {
+				return authFailure, msg.Methods, unexpectedMessageError(msgUserAuthInfoRequest, packet[0])
+			}
 			return authFailure, msg.Methods, nil
 		case msgUserAuthSuccess:
 			return authSuccess, nil, nil
@@ -596,6 +600,7 @@ func (cb KeyboardInteractiveChallenge) auth(session []byte, user string, c packe
 		if err := Unmarshal(packet, &msg); err != nil {
 			return authFailure, nil, err
 		}
+		gotUserAuthInfoRequest = true
 
 		// Manually unpack the prompt/echo pairs.
 		rest := msg.Prompts

ssh/client_auth_test.go

@@ -38,7 +38,7 @@ func tryAuth(t *testing.T, config *ClientConfig) error {
 	return err
 }
 
-// tryAuth runs a handshake with a given config against an SSH server
+// tryAuthWithGSSAPIWithMICConfig runs a handshake with a given config against an SSH server
 // with a given GSSAPIWithMICConfig and config serverConfig. Returns both client and server side errors.
 func tryAuthWithGSSAPIWithMICConfig(t *testing.T, clientConfig *ClientConfig, gssAPIWithMICConfig *GSSAPIWithMICConfig) error {
 	err, _ := tryAuthBothSides(t, clientConfig, gssAPIWithMICConfig)
@@ -324,6 +324,9 @@ func TestMethodInvalidAlgorithm(t *testing.T) {
 }
 
 func TestClientHMAC(t *testing.T) {
+	supportedAlgos := SupportedAlgorithms()
+	insecureAlgos := InsecureAlgorithms()
+	supportedMACs := append(supportedAlgos.MACs, insecureAlgos.MACs...)
 	for _, mac := range supportedMACs {
 		config := &ClientConfig{
 			User: "testuser",
@@ -349,7 +352,7 @@ func TestClientUnsupportedCipher(t *testing.T) {
 			PublicKeys(),
 		},
 		Config: Config{
-			Ciphers: []string{"aes128-cbc"}, // not currently supported
+			Ciphers: []string{"unsupported-cipher"}, // not currently supported
 		},
 	}
 	if err := tryAuth(t, config); err == nil {
@@ -641,17 +644,28 @@ func TestClientAuthMaxAuthTries(t *testing.T) {
 		defer c1.Close()
 		defer c2.Close()
 
-		go newServer(c1, serverConfig)
-		_, _, _, err = NewClientConn(c2, "", clientConfig)
-		if tries > 2 {
-			if err == nil {
+		errCh := make(chan error, 1)
+
+		go func() {
+			_, err := newServer(c1, serverConfig)
+			errCh <- err
+		}()
+		_, _, _, cliErr := NewClientConn(c2, "", clientConfig)
+		srvErr := <-errCh
+
+		if tries > serverConfig.MaxAuthTries {
+			if cliErr == nil {
 				t.Fatalf("client: got no error, want %s", expectedErr)
-			} else if err.Error() != expectedErr.Error() {
+			} else if cliErr.Error() != expectedErr.Error() {
 				t.Fatalf("client: got %s, want %s", err, expectedErr)
 			}
+			var authErr *ServerAuthError
+			if !errors.As(srvErr, &authErr) {
+				t.Errorf("expected ServerAuthError, got: %v", srvErr)
+			}
 		} else {
-			if err != nil {
-				t.Fatalf("client: got %s, want no error", err)
+			if cliErr != nil {
+				t.Fatalf("client: got %s, want no error", cliErr)
 			}
 		}
 	}
@@ -1282,3 +1296,92 @@ func TestCertAuthOpenSSHCompat(t *testing.T) {
 		t.Fatalf("unable to dial remote side: %s", err)
 	}
 }
+
+func TestKeyboardInteractiveAuthEarlyFail(t *testing.T) {
+	const maxAuthTries = 2
+
+	c1, c2, err := netPipe()
+	if err != nil {
+		t.Fatalf("netPipe: %v", err)
+	}
+	defer c1.Close()
+	defer c2.Close()
+
+	// Start testserver
+	serverConfig := &ServerConfig{
+		MaxAuthTries: maxAuthTries,
+		KeyboardInteractiveCallback: func(c ConnMetadata,
+			client KeyboardInteractiveChallenge) (*Permissions, error) {
+			// Fail keyboard-interactive authentication early before
+			// any prompt is sent to client.
+			return nil, errors.New("keyboard-interactive auth failed")
+		},
+		PasswordCallback: func(c ConnMetadata,
+			pass []byte) (*Permissions, error) {
+			if string(pass) == clientPassword {
+				return nil, nil
+			}
+			return nil, errors.New("password auth failed")
+		},
+	}
+	serverConfig.AddHostKey(testSigners["rsa"])
+
+	serverDone := make(chan struct{})
+	go func() {
+		defer func() { serverDone <- struct{}{} }()
+		conn, chans, reqs, err := NewServerConn(c2, serverConfig)
+		if err != nil {
+			return
+		}
+		_ = conn.Close()
+
+		discarderDone := make(chan struct{})
+		go func() {
+			defer func() { discarderDone <- struct{}{} }()
+			DiscardRequests(reqs)
+		}()
+		for newChannel := range chans {
+			newChannel.Reject(Prohibited,
+				"testserver not accepting requests")
+		}
+
+		<-discarderDone
+	}()
+
+	// Connect to testserver, expect KeyboardInteractive() to be not called,
+	// PasswordCallback() to be called and connection to succeed.
+	passwordCallbackCalled := false
+	clientConfig := &ClientConfig{
+		User: "testuser",
+		Auth: []AuthMethod{
+			RetryableAuthMethod(KeyboardInteractive(func(name,
+				instruction string, questions []string,
+				echos []bool) ([]string, error) {
+				t.Errorf("unexpected call to KeyboardInteractive()")
+				return []string{clientPassword}, nil
+			}), maxAuthTries),
+			RetryableAuthMethod(PasswordCallback(func() (secret string,
+				err error) {
+				t.Logf("PasswordCallback()")
+				passwordCallbackCalled = true
+				return clientPassword, nil
+			}), maxAuthTries),
+		},
+		HostKeyCallback: InsecureIgnoreHostKey(),
+	}
+
+	conn, _, _, err := NewClientConn(c1, "", clientConfig)
+	if err != nil {
+		t.Errorf("unexpected NewClientConn() error: %v", err)
+	}
+	if conn != nil {
+		conn.Close()
+	}
+
+	// Wait for server to finish.
+	<-serverDone
+
+	if !passwordCallbackCalled {
+		t.Errorf("expected PasswordCallback() to be called")
+	}
+}

ssh/client_test.go

@@ -292,7 +292,7 @@ func TestUnsupportedAlgorithm(t *testing.T) {
 		{
 			"unsupported and supported KEXs",
 			Config{
-				KeyExchanges: []string{"unsupported", kexAlgoCurve25519SHA256},
+				KeyExchanges: []string{"unsupported", KeyExchangeCurve25519},
 			},
 			"",
 		},
@@ -306,7 +306,7 @@ func TestUnsupportedAlgorithm(t *testing.T) {
 		{
 			"unsupported and supported ciphers",
 			Config{
-				Ciphers: []string{"unsupported", chacha20Poly1305ID},
+				Ciphers: []string{"unsupported", CipherChaCha20Poly1305},
 			},
 			"",
 		},
@@ -315,16 +315,16 @@ func TestUnsupportedAlgorithm(t *testing.T) {
 			Config{
 				MACs: []string{"unsupported"},
 				// MAC is used for non AAED ciphers.
-				Ciphers: []string{"aes256-ctr"},
+				Ciphers: []string{CipherAES256CTR},
 			},
 			"no common algorithm",
 		},
 		{
 			"unsupported and supported MACs",
 			Config{
-				MACs: []string{"unsupported", "hmac-sha2-256-etm@openssh.com"},
+				MACs: []string{"unsupported", HMACSHA256ETM},
 				// MAC is used for non AAED ciphers.
-				Ciphers: []string{"aes256-ctr"},
+				Ciphers: []string{CipherAES256CTR},
 			},
 			"",
 		},

ssh/common.go

@@ -10,6 +10,7 @@ import (
 	"fmt"
 	"io"
 	"math"
+	"slices"
 	"sync"
 
 	_ "crypto/sha1"
@@ -24,69 +25,260 @@ const (
 	serviceSSH      = "ssh-connection"
 )
 
-// supportedCiphers lists ciphers we support but might not recommend.
-var supportedCiphers = []string{
-	"aes128-ctr", "aes192-ctr", "aes256-ctr",
-	"aes128-gcm@openssh.com", gcm256CipherID,
-	chacha20Poly1305ID,
-	"arcfour256", "arcfour128", "arcfour",
-	aes128cbcID,
-	tripledescbcID,
+// The ciphers currently or previously implemented by this library, to use in
+// [Config.Ciphers]. For a list, see the [Algorithms.Ciphers] returned by
+// [SupportedAlgorithms] or [InsecureAlgorithms].
+const (
+	CipherAES128GCM            = "aes128-gcm@openssh.com"
+	CipherAES256GCM            = "aes256-gcm@openssh.com"
+	CipherChaCha20Poly1305     = "chacha20-poly1305@openssh.com"
+	CipherAES128CTR            = "aes128-ctr"
+	CipherAES192CTR            = "aes192-ctr"
+	CipherAES256CTR            = "aes256-ctr"
+	InsecureCipherAES128CBC    = "aes128-cbc"
+	InsecureCipherTripleDESCBC = "3des-cbc"
+	InsecureCipherRC4          = "arcfour"
+	InsecureCipherRC4128       = "arcfour128"
+	InsecureCipherRC4256       = "arcfour256"
+)
+
+// The key exchanges currently or previously implemented by this library, to use
+// in [Config.KeyExchanges]. For a list, see the
+// [Algorithms.KeyExchanges] returned by [SupportedAlgorithms] or
+// [InsecureAlgorithms].
+const (
+	InsecureKeyExchangeDH1SHA1   = "diffie-hellman-group1-sha1"
+	InsecureKeyExchangeDH14SHA1  = "diffie-hellman-group14-sha1"
+	KeyExchangeDH14SHA256        = "diffie-hellman-group14-sha256"
+	KeyExchangeDH16SHA512        = "diffie-hellman-group16-sha512"
+	KeyExchangeECDHP256          = "ecdh-sha2-nistp256"
+	KeyExchangeECDHP384          = "ecdh-sha2-nistp384"
+	KeyExchangeECDHP521          = "ecdh-sha2-nistp521"
+	KeyExchangeCurve25519        = "curve25519-sha256"
+	InsecureKeyExchangeDHGEXSHA1 = "diffie-hellman-group-exchange-sha1"
+	KeyExchangeDHGEXSHA256       = "diffie-hellman-group-exchange-sha256"
+	// KeyExchangeMLKEM768X25519 is supported from Go 1.24.
+	KeyExchangeMLKEM768X25519 = "mlkem768x25519-sha256"
+
+	// An alias for KeyExchangeCurve25519SHA256. This kex ID will be added if
+	// KeyExchangeCurve25519SHA256 is requested for backward compatibility with
+	// OpenSSH versions up to 7.2.
+	keyExchangeCurve25519LibSSH = "curve25519-sha256@libssh.org"
+)
+
+// The message authentication code (MAC) currently or previously implemented by
+// this library, to use in [Config.MACs]. For a list, see the
+// [Algorithms.MACs] returned by [SupportedAlgorithms] or
+// [InsecureAlgorithms].
+const (
+	HMACSHA256ETM      = "hmac-sha2-256-etm@openssh.com"
+	HMACSHA512ETM      = "hmac-sha2-512-etm@openssh.com"
+	HMACSHA256         = "hmac-sha2-256"
+	HMACSHA512         = "hmac-sha2-512"
+	HMACSHA1           = "hmac-sha1"
+	InsecureHMACSHA196 = "hmac-sha1-96"
+)
+
+var (
+	// supportedKexAlgos specifies key-exchange algorithms implemented by this
+	// package in preference order, excluding those with security issues.
+	supportedKexAlgos = []string{
+		KeyExchangeMLKEM768X25519,
+		KeyExchangeCurve25519,
+		KeyExchangeECDHP256,
+		KeyExchangeECDHP384,
+		KeyExchangeECDHP521,
+		KeyExchangeDH14SHA256,
+		KeyExchangeDH16SHA512,
+		KeyExchangeDHGEXSHA256,
+	}
+	// defaultKexAlgos specifies the default preference for key-exchange
+	// algorithms in preference order.
+	defaultKexAlgos = []string{
+		KeyExchangeMLKEM768X25519,
+		KeyExchangeCurve25519,
+		KeyExchangeECDHP256,
+		KeyExchangeECDHP384,
+		KeyExchangeECDHP521,
+		KeyExchangeDH14SHA256,
+		InsecureKeyExchangeDH14SHA1,
+	}
+	// insecureKexAlgos specifies key-exchange algorithms implemented by this
+	// package and which have security issues.
+	insecureKexAlgos = []string{
+		InsecureKeyExchangeDH14SHA1,
+		InsecureKeyExchangeDH1SHA1,
+		InsecureKeyExchangeDHGEXSHA1,
+	}
+	// supportedCiphers specifies cipher algorithms implemented by this package
+	// in preference order, excluding those with security issues.
+	supportedCiphers = []string{
+		CipherAES128GCM,
+		CipherAES256GCM,
+		CipherChaCha20Poly1305,
+		CipherAES128CTR,
+		CipherAES192CTR,
+		CipherAES256CTR,
+	}
+	// defaultCiphers specifies the default preference for ciphers algorithms
+	// in preference order.
+	defaultCiphers = supportedCiphers
+	// insecureCiphers specifies cipher algorithms implemented by this
+	// package and which have security issues.
+	insecureCiphers = []string{
+		InsecureCipherAES128CBC,
+		InsecureCipherTripleDESCBC,
+		InsecureCipherRC4256,
+		InsecureCipherRC4128,
+		InsecureCipherRC4,
+	}
+	// supportedMACs specifies MAC algorithms implemented by this package in
+	// preference order, excluding those with security issues.
+	supportedMACs = []string{
+		HMACSHA256ETM,
+		HMACSHA512ETM,
+		HMACSHA256,
+		HMACSHA512,
+		HMACSHA1,
+	}
+	// defaultMACs specifies the default preference for MAC algorithms in
+	// preference order.
+	defaultMACs = []string{
+		HMACSHA256ETM,
+		HMACSHA512ETM,
+		HMACSHA256,
+		HMACSHA512,
+		HMACSHA1,
+		InsecureHMACSHA196,
+	}
+	// insecureMACs specifies MAC algorithms implemented by this
+	// package and which have security issues.
+	insecureMACs = []string{
+		InsecureHMACSHA196,
+	}
+	// supportedHostKeyAlgos specifies the supported host-key algorithms (i.e.
+	// methods of authenticating servers) implemented by this package in
+	// preference order, excluding those with security issues.
+	supportedHostKeyAlgos = []string{
+		CertAlgoRSASHA256v01,
+		CertAlgoRSASHA512v01,
+		CertAlgoECDSA256v01,
+		CertAlgoECDSA384v01,
+		CertAlgoECDSA521v01,
+		CertAlgoED25519v01,
+		KeyAlgoRSASHA256,
+		KeyAlgoRSASHA512,
+		KeyAlgoECDSA256,
+		KeyAlgoECDSA384,
+		KeyAlgoECDSA521,
+		KeyAlgoED25519,
+	}
+	// defaultHostKeyAlgos specifies the default preference for host-key
+	// algorithms in preference order.
+	defaultHostKeyAlgos = []string{
+		CertAlgoRSASHA256v01,
+		CertAlgoRSASHA512v01,
+		CertAlgoRSAv01,
+		InsecureCertAlgoDSAv01,
+		CertAlgoECDSA256v01,
+		CertAlgoECDSA384v01,
+		CertAlgoECDSA521v01,
+		CertAlgoED25519v01,
+		KeyAlgoECDSA256,
+		KeyAlgoECDSA384,
+		KeyAlgoECDSA521,
+		KeyAlgoRSASHA256,
+		KeyAlgoRSASHA512,
+		KeyAlgoRSA,
+		InsecureKeyAlgoDSA,
+		KeyAlgoED25519,
+	}
+	// insecureHostKeyAlgos specifies host-key algorithms implemented by this
+	// package and which have security issues.
+	insecureHostKeyAlgos = []string{
+		KeyAlgoRSA,
+		InsecureKeyAlgoDSA,
+		CertAlgoRSAv01,
+		InsecureCertAlgoDSAv01,
+	}
+	// supportedPubKeyAuthAlgos specifies the supported client public key
+	// authentication algorithms. Note that this doesn't include certificate
+	// types since those use the underlying algorithm. Order is irrelevant.
+	supportedPubKeyAuthAlgos = []string{
+		KeyAlgoED25519,
+		KeyAlgoSKED25519,
+		KeyAlgoSKECDSA256,
+		KeyAlgoECDSA256,
+		KeyAlgoECDSA384,
+		KeyAlgoECDSA521,
+		KeyAlgoRSASHA256,
+		KeyAlgoRSASHA512,
+	}
+
+	// defaultPubKeyAuthAlgos specifies the preferred client public key
+	// authentication algorithms. This list is sent to the client if it supports
+	// the server-sig-algs extension. Order is irrelevant.
+	defaultPubKeyAuthAlgos = []string{
+		KeyAlgoED25519,
+		KeyAlgoSKED25519,
+		KeyAlgoSKECDSA256,
+		KeyAlgoECDSA256,
+		KeyAlgoECDSA384,
+		KeyAlgoECDSA521,
+		KeyAlgoRSASHA256,
+		KeyAlgoRSASHA512,
+		KeyAlgoRSA,
+		InsecureKeyAlgoDSA,
+	}
+	// insecurePubKeyAuthAlgos specifies client public key authentication
+	// algorithms implemented by this package and which have security issues.
+	insecurePubKeyAuthAlgos = []string{
+		KeyAlgoRSA,
+		InsecureKeyAlgoDSA,
+	}
+)
+
+// NegotiatedAlgorithms defines algorithms negotiated between client and server.
+type NegotiatedAlgorithms struct {
+	KeyExchange string
+	HostKey     string
+	Read        DirectionAlgorithms
+	Write       DirectionAlgorithms
 }
 
-// preferredCiphers specifies the default preference for ciphers.
-var preferredCiphers = []string{
-	"aes128-gcm@openssh.com", gcm256CipherID,
-	chacha20Poly1305ID,
-	"aes128-ctr", "aes192-ctr", "aes256-ctr",
+// Algorithms defines a set of algorithms that can be configured in the client
+// or server config for negotiation during a handshake.
+type Algorithms struct {
+	KeyExchanges   []string
+	Ciphers        []string
+	MACs           []string
+	HostKeys       []string
+	PublicKeyAuths []string
 }
 
-// supportedKexAlgos specifies the supported key-exchange algorithms in
-// preference order.
-var supportedKexAlgos = []string{
-	kexAlgoCurve25519SHA256, kexAlgoCurve25519SHA256LibSSH,
-	// P384 and P521 are not constant-time yet, but since we don't
-	// reuse ephemeral keys, using them for ECDH should be OK.
-	kexAlgoECDH256, kexAlgoECDH384, kexAlgoECDH521,
-	kexAlgoDH14SHA256, kexAlgoDH16SHA512, kexAlgoDH14SHA1,
-	kexAlgoDH1SHA1,
+// SupportedAlgorithms returns algorithms currently implemented by this package,
+// excluding those with security issues, which are returned by
+// InsecureAlgorithms. The algorithms listed here are in preference order.
+func SupportedAlgorithms() Algorithms {
+	return Algorithms{
+		Ciphers:        slices.Clone(supportedCiphers),
+		MACs:           slices.Clone(supportedMACs),
+		KeyExchanges:   slices.Clone(supportedKexAlgos),
+		HostKeys:       slices.Clone(supportedHostKeyAlgos),
+		PublicKeyAuths: slices.Clone(supportedPubKeyAuthAlgos),
+	}
 }
 
-// serverForbiddenKexAlgos contains key exchange algorithms, that are forbidden
-// for the server half.
-var serverForbiddenKexAlgos = map[string]struct{}{
-	kexAlgoDHGEXSHA1:   {}, // server half implementation is only minimal to satisfy the automated tests
-	kexAlgoDHGEXSHA256: {}, // server half implementation is only minimal to satisfy the automated tests
-}
-
-// preferredKexAlgos specifies the default preference for key-exchange
-// algorithms in preference order. The diffie-hellman-group16-sha512 algorithm
-// is disabled by default because it is a bit slower than the others.
-var preferredKexAlgos = []string{
-	kexAlgoCurve25519SHA256, kexAlgoCurve25519SHA256LibSSH,
-	kexAlgoECDH256, kexAlgoECDH384, kexAlgoECDH521,
-	kexAlgoDH14SHA256, kexAlgoDH14SHA1,
-}
-
-// supportedHostKeyAlgos specifies the supported host-key algorithms (i.e. methods
-// of authenticating servers) in preference order.
-var supportedHostKeyAlgos = []string{
-	CertAlgoRSASHA256v01, CertAlgoRSASHA512v01,
-	CertAlgoRSAv01, CertAlgoDSAv01, CertAlgoECDSA256v01,
-	CertAlgoECDSA384v01, CertAlgoECDSA521v01, CertAlgoED25519v01,
-
-	KeyAlgoECDSA256, KeyAlgoECDSA384, KeyAlgoECDSA521,
-	KeyAlgoRSASHA256, KeyAlgoRSASHA512,
-	KeyAlgoRSA, KeyAlgoDSA,
-
-	KeyAlgoED25519,
-}
-
-// supportedMACs specifies a default set of MAC algorithms in preference order.
-// This is based on RFC 4253, section 6.4, but with hmac-md5 variants removed
-// because they have reached the end of their useful life.
-var supportedMACs = []string{
-	"hmac-sha2-256-etm@openssh.com", "hmac-sha2-512-etm@openssh.com", "hmac-sha2-256", "hmac-sha2-512", "hmac-sha1", "hmac-sha1-96",
+// InsecureAlgorithms returns algorithms currently implemented by this package
+// and which have security issues.
+func InsecureAlgorithms() Algorithms {
+	return Algorithms{
+		KeyExchanges:   slices.Clone(insecureKexAlgos),
+		Ciphers:        slices.Clone(insecureCiphers),
+		MACs:           slices.Clone(insecureMACs),
+		HostKeys:       slices.Clone(insecureHostKeyAlgos),
+		PublicKeyAuths: slices.Clone(insecurePubKeyAuthAlgos),
+	}
 }
 
 var supportedCompressions = []string{compressionNone}
@@ -94,13 +286,13 @@ var supportedCompressions = []string{compressionNone}
 // hashFuncs keeps the mapping of supported signature algorithms to their
 // respective hashes needed for signing and verification.
 var hashFuncs = map[string]crypto.Hash{
-	KeyAlgoRSA:       crypto.SHA1,
-	KeyAlgoRSASHA256: crypto.SHA256,
-	KeyAlgoRSASHA512: crypto.SHA512,
-	KeyAlgoDSA:       crypto.SHA1,
-	KeyAlgoECDSA256:  crypto.SHA256,
-	KeyAlgoECDSA384:  crypto.SHA384,
-	KeyAlgoECDSA521:  crypto.SHA512,
+	KeyAlgoRSA:         crypto.SHA1,
+	KeyAlgoRSASHA256:   crypto.SHA256,
+	KeyAlgoRSASHA512:   crypto.SHA512,
+	InsecureKeyAlgoDSA: crypto.SHA1,
+	KeyAlgoECDSA256:    crypto.SHA256,
+	KeyAlgoECDSA384:    crypto.SHA384,
+	KeyAlgoECDSA521:    crypto.SHA512,
 	// KeyAlgoED25519 doesn't pre-hash.
 	KeyAlgoSKECDSA256: crypto.SHA256,
 	KeyAlgoSKED25519:  crypto.SHA256,
@@ -135,18 +327,6 @@ func isRSACert(algo string) bool {
 	return isRSA(algo)
 }
 
-// supportedPubKeyAuthAlgos specifies the supported client public key
-// authentication algorithms. Note that this doesn't include certificate types
-// since those use the underlying algorithm. This list is sent to the client if
-// it supports the server-sig-algs extension. Order is irrelevant.
-var supportedPubKeyAuthAlgos = []string{
-	KeyAlgoED25519,
-	KeyAlgoSKED25519, KeyAlgoSKECDSA256,
-	KeyAlgoECDSA256, KeyAlgoECDSA384, KeyAlgoECDSA521,
-	KeyAlgoRSASHA256, KeyAlgoRSASHA512, KeyAlgoRSA,
-	KeyAlgoDSA,
-}
-
 // unexpectedMessageError results when the SSH message that we received didn't
 // match what we wanted.
 func unexpectedMessageError(expected, got uint8) error {
@@ -158,7 +338,7 @@ func parseError(tag uint8) error {
 	return fmt.Errorf("ssh: parse error in message type %d", tag)
 }
 
-func findCommon(what string, client []string, server []string) (common string, err error) {
+func findCommon(what string, client []string, server []string, isClient bool) (string, error) {
 	for _, c := range client {
 		for _, s := range server {
 			if c == s {
@@ -166,23 +346,49 @@ func findCommon(what string, client []string, server []string) (common string, e
 			}
 		}
 	}
-	return "", fmt.Errorf("ssh: no common algorithm for %s; client offered: %v, server offered: %v", what, client, server)
+	err := &AlgorithmNegotiationError{
+		What: what,
+	}
+	if isClient {
+		err.SupportedAlgorithms = client
+		err.RequestedAlgorithms = server
+	} else {
+		err.SupportedAlgorithms = server
+		err.RequestedAlgorithms = client
+	}
+	return "", err
 }
 
-// directionAlgorithms records algorithm choices in one direction (either read or write)
-type directionAlgorithms struct {
+// AlgorithmNegotiationError defines the error returned if the client and the
+// server cannot agree on an algorithm for key exchange, host key, cipher, MAC.
+type AlgorithmNegotiationError struct {
+	What string
+	// RequestedAlgorithms lists the algorithms supported by the peer.
+	RequestedAlgorithms []string
+	// SupportedAlgorithms lists the algorithms supported on our side.
+	SupportedAlgorithms []string
+}
+
+func (a *AlgorithmNegotiationError) Error() string {
+	return fmt.Sprintf("ssh: no common algorithm for %s; we offered: %v, peer offered: %v",
+		a.What, a.SupportedAlgorithms, a.RequestedAlgorithms)
+}
+
+// DirectionAlgorithms defines the algorithms negotiated in one direction
+// (either read or write).
+type DirectionAlgorithms struct {
 	Cipher      string
 	MAC         string
-	Compression string
+	compression string
 }
 
 // rekeyBytes returns a rekeying intervals in bytes.
-func (a *directionAlgorithms) rekeyBytes() int64 {
+func (a *DirectionAlgorithms) rekeyBytes() int64 {
 	// According to RFC 4344 block ciphers should rekey after
 	// 2^(BLOCKSIZE/4) blocks. For all AES flavors BLOCKSIZE is
 	// 128.
 	switch a.Cipher {
-	case "aes128-ctr", "aes192-ctr", "aes256-ctr", gcm128CipherID, gcm256CipherID, aes128cbcID:
+	case CipherAES128CTR, CipherAES192CTR, CipherAES256CTR, CipherAES128GCM, CipherAES256GCM, InsecureCipherAES128CBC:
 		return 16 * (1 << 32)
 
 	}
@@ -192,66 +398,59 @@ func (a *directionAlgorithms) rekeyBytes() int64 {
 }
 
 var aeadCiphers = map[string]bool{
-	gcm128CipherID:     true,
-	gcm256CipherID:     true,
-	chacha20Poly1305ID: true,
+	CipherAES128GCM:        true,
+	CipherAES256GCM:        true,
+	CipherChaCha20Poly1305: true,
 }
 
-type algorithms struct {
-	kex     string
-	hostKey string
-	w       directionAlgorithms
-	r       directionAlgorithms
-}
+func findAgreedAlgorithms(isClient bool, clientKexInit, serverKexInit *kexInitMsg) (algs *NegotiatedAlgorithms, err error) {
+	result := &NegotiatedAlgorithms{}
 
-func findAgreedAlgorithms(isClient bool, clientKexInit, serverKexInit *kexInitMsg) (algs *algorithms, err error) {
-	result := &algorithms{}
-
-	result.kex, err = findCommon("key exchange", clientKexInit.KexAlgos, serverKexInit.KexAlgos)
+	result.KeyExchange, err = findCommon("key exchange", clientKexInit.KexAlgos, serverKexInit.KexAlgos, isClient)
 	if err != nil {
 		return
 	}
 
-	result.hostKey, err = findCommon("host key", clientKexInit.ServerHostKeyAlgos, serverKexInit.ServerHostKeyAlgos)
+	result.HostKey, err = findCommon("host key", clientKexInit.ServerHostKeyAlgos, serverKexInit.ServerHostKeyAlgos, isClient)
 	if err != nil {
 		return
 	}
 
-	stoc, ctos := &result.w, &result.r
+	stoc, ctos := &result.Write, &result.Read
 	if isClient {
 		ctos, stoc = stoc, ctos
 	}
 
-	ctos.Cipher, err = findCommon("client to server cipher", clientKexInit.CiphersClientServer, serverKexInit.CiphersClientServer)
+	ctos.Cipher, err = findCommon("client to server cipher", clientKexInit.CiphersClientServer, serverKexInit.CiphersClientServer, isClient)
 	if err != nil {
 		return
 	}
 
-	stoc.Cipher, err = findCommon("server to client cipher", clientKexInit.CiphersServerClient, serverKexInit.CiphersServerClient)
+	stoc.Cipher, err = findCommon("server to client cipher", clientKexInit.CiphersServerClient, serverKexInit.CiphersServerClient, isClient)
 	if err != nil {
 		return
 	}
 
 	if !aeadCiphers[ctos.Cipher] {
-		ctos.MAC, err = findCommon("client to server MAC", clientKexInit.MACsClientServer, serverKexInit.MACsClientServer)
+		ctos.MAC, err = findCommon("client to server MAC", clientKexInit.MACsClientServer, serverKexInit.MACsClientServer, isClient)
 		if err != nil {
 			return
 		}
 	}
 
 	if !aeadCiphers[stoc.Cipher] {
-		stoc.MAC, err = findCommon("server to client MAC", clientKexInit.MACsServerClient, serverKexInit.MACsServerClient)
+		stoc.MAC, err = findCommon("server to client MAC", clientKexInit.MACsServerClient, serverKexInit.MACsServerClient, isClient)
 		if err != nil {
 			return
 		}
 	}
 
-	ctos.Compression, err = findCommon("client to server compression", clientKexInit.CompressionClientServer, serverKexInit.CompressionClientServer)
+	ctos.compression, err = findCommon("client to server compression", clientKexInit.CompressionClientServer, serverKexInit.CompressionClientServer, isClient)
 	if err != nil {
 		return
 	}
 
-	stoc.Compression, err = findCommon("server to client compression", clientKexInit.CompressionServerClient, serverKexInit.CompressionServerClient)
+	stoc.compression, err = findCommon("server to client compression", clientKexInit.CompressionServerClient, serverKexInit.CompressionServerClient, isClient)
 	if err != nil {
 		return
 	}
@@ -297,7 +496,7 @@ func (c *Config) SetDefaults() {
 		c.Rand = rand.Reader
 	}
 	if c.Ciphers == nil {
-		c.Ciphers = preferredCiphers
+		c.Ciphers = defaultCiphers
 	}
 	var ciphers []string
 	for _, c := range c.Ciphers {
@@ -309,19 +508,22 @@ func (c *Config) SetDefaults() {
 	c.Ciphers = ciphers
 
 	if c.KeyExchanges == nil {
-		c.KeyExchanges = preferredKexAlgos
+		c.KeyExchanges = defaultKexAlgos
 	}
 	var kexs []string
 	for _, k := range c.KeyExchanges {
 		if kexAlgoMap[k] != nil {
 			// Ignore the KEX if we have no kexAlgoMap definition.
 			kexs = append(kexs, k)
+			if k == KeyExchangeCurve25519 && !contains(c.KeyExchanges, keyExchangeCurve25519LibSSH) {
+				kexs = append(kexs, keyExchangeCurve25519LibSSH)
+			}
 		}
 	}
 	c.KeyExchanges = kexs
 
 	if c.MACs == nil {
-		c.MACs = supportedMACs
+		c.MACs = defaultMACs
 	}
 	var macs []string
 	for _, m := range c.MACs {

ssh/common_test.go

@@ -51,33 +51,33 @@ func TestFindAgreedAlgorithms(t *testing.T) {
 		}
 	}
 
-	initDirAlgs := func(a *directionAlgorithms) {
+	initDirAlgs := func(a *DirectionAlgorithms) {
 		if a.Cipher == "" {
 			a.Cipher = "cipher1"
 		}
 		if a.MAC == "" {
 			a.MAC = "mac1"
 		}
-		if a.Compression == "" {
-			a.Compression = "compression1"
+		if a.compression == "" {
+			a.compression = "compression1"
 		}
 	}
 
-	initAlgs := func(a *algorithms) {
-		if a.kex == "" {
-			a.kex = "kex1"
+	initAlgs := func(a *NegotiatedAlgorithms) {
+		if a.KeyExchange == "" {
+			a.KeyExchange = "kex1"
 		}
-		if a.hostKey == "" {
-			a.hostKey = "hostkey1"
+		if a.HostKey == "" {
+			a.HostKey = "hostkey1"
 		}
-		initDirAlgs(&a.r)
-		initDirAlgs(&a.w)
+		initDirAlgs(&a.Read)
+		initDirAlgs(&a.Write)
 	}
 
 	type testcase struct {
 		name                   string
 		clientIn, serverIn     kexInitMsg
-		wantClient, wantServer algorithms
+		wantClient, wantServer NegotiatedAlgorithms
 		wantErr                bool
 	}
 
@@ -120,19 +120,19 @@ func TestFindAgreedAlgorithms(t *testing.T) {
 				CiphersClientServer: []string{"cipher2", "cipher1"},
 				CiphersServerClient: []string{"cipher3", "cipher2"},
 			},
-			wantClient: algorithms{
-				r: directionAlgorithms{
+			wantClient: NegotiatedAlgorithms{
+				Read: DirectionAlgorithms{
 					Cipher: "cipher3",
 				},
-				w: directionAlgorithms{
+				Write: DirectionAlgorithms{
 					Cipher: "cipher2",
 				},
 			},
-			wantServer: algorithms{
-				w: directionAlgorithms{
+			wantServer: NegotiatedAlgorithms{
+				Write: DirectionAlgorithms{
 					Cipher: "cipher3",
 				},
-				r: directionAlgorithms{
+				Read: DirectionAlgorithms{
 					Cipher: "cipher2",
 				},
 			},

ssh/connection.go

@@ -74,6 +74,13 @@ type Conn interface {
 	//   Disconnect
 }
 
+// AlgorithmsConnMetadata is a ConnMetadata that can return the algorithms
+// negotiated between client and server.
+type AlgorithmsConnMetadata interface {
+	ConnMetadata
+	Algorithms() NegotiatedAlgorithms
+}
+
 // DiscardRequests consumes and rejects all requests from the
 // passed-in channel.
 func DiscardRequests(in <-chan *Request) {
@@ -106,6 +113,7 @@ type sshConn struct {
 	sessionID     []byte
 	clientVersion []byte
 	serverVersion []byte
+	algorithms    NegotiatedAlgorithms
 }
 
 func dup(src []byte) []byte {
@@ -141,3 +149,7 @@ func (c *sshConn) ClientVersion() []byte {
 func (c *sshConn) ServerVersion() []byte {
 	return dup(c.serverVersion)
 }
+
+func (c *sshConn) Algorithms() NegotiatedAlgorithms {
+	return c.algorithms
+}

ssh/doc.go

@@ -16,6 +16,7 @@ References:
 	[PROTOCOL]: https://cvsweb.openbsd.org/cgi-bin/cvsweb/src/usr.bin/ssh/PROTOCOL?rev=HEAD
 	[PROTOCOL.certkeys]: http://cvsweb.openbsd.org/cgi-bin/cvsweb/src/usr.bin/ssh/PROTOCOL.certkeys?rev=HEAD
 	[SSH-PARAMETERS]:    http://www.iana.org/assignments/ssh-parameters/ssh-parameters.xml#ssh-parameters-1
+	[SSH-CERTS]:	https://datatracker.ietf.org/doc/html/draft-miller-ssh-cert-01
 
 This package does not fall under the stability promise of the Go language itself,
 so its API may be changed when pressing needs arise.

ssh/example_test.go

@@ -154,6 +154,75 @@ func ExampleNewServerConn() {
 	}
 }
 
+func ExampleServerConfig() {
+	// Minimal ServerConfig with SHA-1 algoritms disabled and supporting only
+	// public key authentication.
+
+	// The algorithms returned by ssh.SupportedAlgorithms() are different from
+	// the default ones and do not include algorithms that are considered
+	// insecure, such as those using SHA-1, returned by
+	// ssh.InsecureAlgorithms().
+	algorithms := ssh.SupportedAlgorithms()
+
+	// Public key authentication is done by comparing
+	// the public key of a received connection
+	// with the entries in the authorized_keys file.
+	authorizedKeysBytes, err := os.ReadFile("authorized_keys")
+	if err != nil {
+		log.Fatalf("Failed to load authorized_keys, err: %v", err)
+	}
+
+	authorizedKeysMap := map[string]bool{}
+	for len(authorizedKeysBytes) > 0 {
+		pubKey, _, _, rest, err := ssh.ParseAuthorizedKey(authorizedKeysBytes)
+		if err != nil {
+			log.Fatal(err)
+		}
+
+		authorizedKeysMap[string(pubKey.Marshal())] = true
+		authorizedKeysBytes = rest
+	}
+
+	config := &ssh.ServerConfig{
+		Config: ssh.Config{
+			KeyExchanges: algorithms.KeyExchanges,
+			Ciphers:      algorithms.Ciphers,
+			MACs:         algorithms.MACs,
+		},
+		// The configured PublicKeyAuthAlgorithms do not contain SHA-1 based
+		// signature formats, so if the client attempts to use them the
+		// authentication will fail before calling the defined callback.
+		PublicKeyAuthAlgorithms: algorithms.PublicKeyAuths,
+		PublicKeyCallback: func(c ssh.ConnMetadata, pubKey ssh.PublicKey) (*ssh.Permissions, error) {
+			if authorizedKeysMap[string(pubKey.Marshal())] {
+				return &ssh.Permissions{
+					// Record the public key used for authentication.
+					Extensions: map[string]string{
+						"pubkey-fp": ssh.FingerprintSHA256(pubKey),
+					},
+				}, nil
+			}
+			return nil, fmt.Errorf("unknown public key for %q", c.User())
+		},
+	}
+
+	privateBytes, err := os.ReadFile("id_rsa")
+	if err != nil {
+		log.Fatal("Failed to load private key: ", err)
+	}
+
+	private, err := ssh.ParsePrivateKey(privateBytes)
+	if err != nil {
+		log.Fatal("Failed to parse private key: ", err)
+	}
+	// Restrict host key algorithms to disable ssh-rsa.
+	signer, err := ssh.NewSignerWithAlgorithms(private.(ssh.AlgorithmSigner), []string{ssh.KeyAlgoRSASHA256, ssh.KeyAlgoRSASHA512})
+	if err != nil {
+		log.Fatal("Failed to create private key with restricted algorithms: ", err)
+	}
+	config.AddHostKey(signer)
+}
+
 func ExampleServerConfig_AddHostKey() {
 	// Minimal ServerConfig supporting only password authentication.
 	config := &ssh.ServerConfig{
@@ -262,6 +331,47 @@ func ExampleDial() {
 	fmt.Println(b.String())
 }
 
+func ExampleClientConfig() {
+	var hostKey ssh.PublicKey
+	key, err := os.ReadFile("/home/user/.ssh/id_rsa")
+	if err != nil {
+		log.Fatalf("unable to read private key: %v", err)
+	}
+
+	// Create the Signer for this private key.
+	signer, err := ssh.ParsePrivateKey(key)
+	if err != nil {
+		log.Fatalf("unable to parse private key: %v", err)
+	}
+
+	// Minimal ClientConfig with SHA-1 algoritms disabled.
+	// The algorithms returned by ssh.SupportedAlgorithms() are different from
+	// the default ones and do not include algorithms that are considered
+	// insecure, such as those using SHA-1, returned by
+	// ssh.InsecureAlgorithms().
+	algorithms := ssh.SupportedAlgorithms()
+	config := &ssh.ClientConfig{
+		Config: ssh.Config{
+			KeyExchanges: algorithms.KeyExchanges,
+			Ciphers:      algorithms.Ciphers,
+			MACs:         algorithms.MACs,
+		},
+		User: "username",
+		Auth: []ssh.AuthMethod{
+			ssh.PublicKeys(signer),
+		},
+		HostKeyCallback: ssh.FixedHostKey(hostKey),
+		// We should check that hostKey algorithm is inlcuded in
+		// algorithms.HostKeys.
+		HostKeyAlgorithms: algorithms.HostKeys,
+	}
+	client, err := ssh.Dial("tcp", "yourserver.com:22", config)
+	if err != nil {
+		log.Fatal("Failed to dial: ", err)
+	}
+	defer client.Close()
+}
+
 func ExamplePublicKeys() {
 	var hostKey ssh.PublicKey
 	// A public key may be used to authenticate against the remote

ssh/handshake.go

@@ -5,7 +5,6 @@
 package ssh
 
 import (
-	"crypto/rand"
 	"errors"
 	"fmt"
 	"io"
@@ -25,6 +24,11 @@ const debugHandshake = false
 // quickly.
 const chanSize = 16
 
+// maxPendingPackets sets the maximum number of packets to queue while waiting
+// for KEX to complete. This limits the total pending data to maxPendingPackets
+// * maxPacket bytes, which is ~16.8MB.
+const maxPendingPackets = 64
+
 // keyingTransport is a packet based transport that supports key
 // changes. It need not be thread-safe. It should pass through
 // msgNewKeys in both directions.
@@ -34,7 +38,7 @@ type keyingTransport interface {
 	// prepareKeyChange sets up a key change. The key change for a
 	// direction will be effected if a msgNewKeys message is sent
 	// or received.
-	prepareKeyChange(*algorithms, *kexResult) error
+	prepareKeyChange(*NegotiatedAlgorithms, *kexResult) error
 
 	// setStrictMode sets the strict KEX mode, notably triggering
 	// sequence number resets on sending or receiving msgNewKeys.
@@ -73,13 +77,22 @@ type handshakeTransport struct {
 	incoming  chan []byte
 	readError error
 
-	mu               sync.Mutex
-	writeError       error
-	sentInitPacket   []byte
-	sentInitMsg      *kexInitMsg
-	pendingPackets   [][]byte // Used when a key exchange is in progress.
+	mu sync.Mutex
+	// Condition for the above mutex. It is used to notify a completed key
+	// exchange or a write failure. Writes can wait for this condition while a
+	// key exchange is in progress.
+	writeCond      *sync.Cond
+	writeError     error
+	sentInitPacket []byte
+	sentInitMsg    *kexInitMsg
+	// Used to queue writes when a key exchange is in progress. The length is
+	// limited by pendingPacketsSize. Once full, writes will block until the key
+	// exchange is completed or an error occurs. If not empty, it is emptied
+	// all at once when the key exchange is completed in kexLoop.
+	pendingPackets   [][]byte
 	writePacketsLeft uint32
 	writeBytesLeft   int64
+	userAuthComplete bool // whether the user authentication phase is complete
 
 	// If the read loop wants to schedule a kex, it pings this
 	// channel, and the write loop will send out a kex
@@ -102,7 +115,7 @@ type handshakeTransport struct {
 	bannerCallback BannerCallback
 
 	// Algorithms agreed in the last key exchange.
-	algorithms *algorithms
+	algorithms *NegotiatedAlgorithms
 
 	// Counters exclusively owned by readLoop.
 	readPacketsLeft uint32
@@ -133,6 +146,7 @@ func newHandshakeTransport(conn keyingTransport, config *Config, clientVersion,
 
 		config: config,
 	}
+	t.writeCond = sync.NewCond(&t.mu)
 	t.resetReadThresholds()
 	t.resetWriteThresholds()
 
@@ -150,7 +164,7 @@ func newClientTransport(conn keyingTransport, clientVersion, serverVersion []byt
 	if config.HostKeyAlgorithms != nil {
 		t.hostKeyAlgorithms = config.HostKeyAlgorithms
 	} else {
-		t.hostKeyAlgorithms = supportedHostKeyAlgos
+		t.hostKeyAlgorithms = defaultHostKeyAlgos
 	}
 	go t.readLoop()
 	go t.kexLoop()
@@ -170,6 +184,10 @@ func (t *handshakeTransport) getSessionID() []byte {
 	return t.sessionID
 }
 
+func (t *handshakeTransport) getAlgorithms() NegotiatedAlgorithms {
+	return *t.algorithms
+}
+
 // waitSession waits for the session to be established. This should be
 // the first thing to call after instantiating handshakeTransport.
 func (t *handshakeTransport) waitSession() error {
@@ -259,6 +277,7 @@ func (t *handshakeTransport) recordWriteError(err error) {
 	defer t.mu.Unlock()
 	if t.writeError == nil && err != nil {
 		t.writeError = err
+		t.writeCond.Broadcast()
 	}
 }
 
@@ -275,7 +294,7 @@ func (t *handshakeTransport) resetWriteThresholds() {
 	if t.config.RekeyThreshold > 0 {
 		t.writeBytesLeft = int64(t.config.RekeyThreshold)
 	} else if t.algorithms != nil {
-		t.writeBytesLeft = t.algorithms.w.rekeyBytes()
+		t.writeBytesLeft = t.algorithms.Write.rekeyBytes()
 	} else {
 		t.writeBytesLeft = 1 << 30
 	}
@@ -362,6 +381,8 @@ write:
 			}
 		}
 		t.pendingPackets = t.pendingPackets[:0]
+		// Unblock writePacket if waiting for KEX.
+		t.writeCond.Broadcast()
 		t.mu.Unlock()
 	}
 
@@ -390,7 +411,7 @@ func (t *handshakeTransport) resetReadThresholds() {
 	if t.config.RekeyThreshold > 0 {
 		t.readBytesLeft = int64(t.config.RekeyThreshold)
 	} else if t.algorithms != nil {
-		t.readBytesLeft = t.algorithms.r.rekeyBytes()
+		t.readBytesLeft = t.algorithms.Read.rekeyBytes()
 	} else {
 		t.readBytesLeft = 1 << 30
 	}
@@ -483,7 +504,7 @@ func (t *handshakeTransport) sendKexInit() error {
 		CompressionClientServer: supportedCompressions,
 		CompressionServerClient: supportedCompressions,
 	}
-	io.ReadFull(rand.Reader, msg.Cookie[:])
+	io.ReadFull(t.config.Rand, msg.Cookie[:])
 
 	// We mutate the KexAlgos slice, in order to add the kex-strict extension algorithm,
 	// and possibly to add the ext-info extension algorithm. Since the slice may be the
@@ -552,26 +573,44 @@ func (t *handshakeTransport) sendKexInit() error {
 	return nil
 }
 
+var errSendBannerPhase = errors.New("ssh: SendAuthBanner outside of authentication phase")
+
 func (t *handshakeTransport) writePacket(p []byte) error {
+	t.mu.Lock()
+	defer t.mu.Unlock()
+
 	switch p[0] {
 	case msgKexInit:
 		return errors.New("ssh: only handshakeTransport can send kexInit")
 	case msgNewKeys:
 		return errors.New("ssh: only handshakeTransport can send newKeys")
+	case msgUserAuthBanner:
+		if t.userAuthComplete {
+			return errSendBannerPhase
+		}
+	case msgUserAuthSuccess:
+		t.userAuthComplete = true
 	}
 
-	t.mu.Lock()
-	defer t.mu.Unlock()
 	if t.writeError != nil {
 		return t.writeError
 	}
 
 	if t.sentInitMsg != nil {
-		// Copy the packet so the writer can reuse the buffer.
-		cp := make([]byte, len(p))
-		copy(cp, p)
-		t.pendingPackets = append(t.pendingPackets, cp)
-		return nil
+		if len(t.pendingPackets) < maxPendingPackets {
+			// Copy the packet so the writer can reuse the buffer.
+			cp := make([]byte, len(p))
+			copy(cp, p)
+			t.pendingPackets = append(t.pendingPackets, cp)
+			return nil
+		}
+		for t.sentInitMsg != nil {
+			// Block and wait for KEX to complete or an error.
+			t.writeCond.Wait()
+			if t.writeError != nil {
+				return t.writeError
+			}
+		}
 	}
 
 	if t.writeBytesLeft > 0 {
@@ -588,6 +627,7 @@ func (t *handshakeTransport) writePacket(p []byte) error {
 
 	if err := t.pushPacket(p); err != nil {
 		t.writeError = err
+		t.writeCond.Broadcast()
 	}
 
 	return nil
@@ -664,9 +704,9 @@ func (t *handshakeTransport) enterKeyExchange(otherInitPacket []byte) error {
 		}
 	}
 
-	kex, ok := kexAlgoMap[t.algorithms.kex]
+	kex, ok := kexAlgoMap[t.algorithms.KeyExchange]
 	if !ok {
-		return fmt.Errorf("ssh: unexpected key exchange algorithm %v", t.algorithms.kex)
+		return fmt.Errorf("ssh: unexpected key exchange algorithm %v", t.algorithms.KeyExchange)
 	}
 
 	var result *kexResult
@@ -773,12 +813,12 @@ func pickHostKey(hostKeys []Signer, algo string) AlgorithmSigner {
 }
 
 func (t *handshakeTransport) server(kex kexAlgorithm, magics *handshakeMagics) (*kexResult, error) {
-	hostKey := pickHostKey(t.hostKeys, t.algorithms.hostKey)
+	hostKey := pickHostKey(t.hostKeys, t.algorithms.HostKey)
 	if hostKey == nil {
 		return nil, errors.New("ssh: internal error: negotiated unsupported signature type")
 	}
 
-	r, err := kex.Server(t.conn, t.config.Rand, magics, hostKey, t.algorithms.hostKey)
+	r, err := kex.Server(t.conn, t.config.Rand, magics, hostKey, t.algorithms.HostKey)
 	return r, err
 }
 
@@ -793,7 +833,7 @@ func (t *handshakeTransport) client(kex kexAlgorithm, magics *handshakeMagics) (
 		return nil, err
 	}
 
-	if err := verifyHostKeySignature(hostKey, t.algorithms.hostKey, result); err != nil {
+	if err := verifyHostKeySignature(hostKey, t.algorithms.HostKey, result); err != nil {
 		return nil, err
 	}
 

ssh/handshake_test.go

@@ -367,7 +367,7 @@ type errorKeyingTransport struct {
 	readLeft, writeLeft int
 }
 
-func (n *errorKeyingTransport) prepareKeyChange(*algorithms, *kexResult) error {
+func (n *errorKeyingTransport) prepareKeyChange(*NegotiatedAlgorithms, *kexResult) error {
 	return nil
 }
 
@@ -539,10 +539,230 @@ func TestDisconnect(t *testing.T) {
 	}
 }
 
+type mockKeyingTransport struct {
+	packetConn
+	kexInitAllowed chan struct{}
+	kexInitSent    chan struct{}
+}
+
+func (n *mockKeyingTransport) prepareKeyChange(*NegotiatedAlgorithms, *kexResult) error {
+	return nil
+}
+
+func (n *mockKeyingTransport) writePacket(packet []byte) error {
+	if packet[0] == msgKexInit {
+		<-n.kexInitAllowed
+		n.kexInitSent <- struct{}{}
+	}
+	return n.packetConn.writePacket(packet)
+}
+
+func (n *mockKeyingTransport) readPacket() ([]byte, error) {
+	return n.packetConn.readPacket()
+}
+
+func (n *mockKeyingTransport) setStrictMode() error { return nil }
+
+func (n *mockKeyingTransport) setInitialKEXDone() {}
+
+func TestHandshakePendingPacketsWait(t *testing.T) {
+	a, b := memPipe()
+
+	trS := &mockKeyingTransport{
+		packetConn:     a,
+		kexInitAllowed: make(chan struct{}, 2),
+		kexInitSent:    make(chan struct{}, 2),
+	}
+	// Allow the first KEX.
+	trS.kexInitAllowed <- struct{}{}
+
+	trC := &mockKeyingTransport{
+		packetConn:     b,
+		kexInitAllowed: make(chan struct{}, 2),
+		kexInitSent:    make(chan struct{}, 2),
+	}
+	// Allow the first KEX.
+	trC.kexInitAllowed <- struct{}{}
+
+	clientConf := &ClientConfig{
+		HostKeyCallback: InsecureIgnoreHostKey(),
+	}
+	clientConf.SetDefaults()
+
+	v := []byte("version")
+	client := newClientTransport(trC, v, v, clientConf, "addr", nil)
+
+	serverConf := &ServerConfig{}
+	serverConf.AddHostKey(testSigners["ecdsa"])
+	serverConf.AddHostKey(testSigners["rsa"])
+	serverConf.SetDefaults()
+	server := newServerTransport(trS, v, v, serverConf)
+
+	if err := server.waitSession(); err != nil {
+		t.Fatalf("server.waitSession: %v", err)
+	}
+	if err := client.waitSession(); err != nil {
+		t.Fatalf("client.waitSession: %v", err)
+	}
+
+	<-trC.kexInitSent
+	<-trS.kexInitSent
+
+	// Allow and request new KEX server side.
+	trS.kexInitAllowed <- struct{}{}
+	server.requestKeyExchange()
+	// Wait until the KEX init is sent.
+	<-trS.kexInitSent
+	// The client is not allowed to respond to the KEX, so writes will be
+	// blocked on the server side once the packets queue is full.
+	for i := 0; i < maxPendingPackets; i++ {
+		p := []byte{msgRequestSuccess, byte(i)}
+		if err := server.writePacket(p); err != nil {
+			t.Errorf("unexpected write error: %v", err)
+		}
+	}
+	// The packets queue is now full, the next write will block.
+	server.mu.Lock()
+	if len(server.pendingPackets) != maxPendingPackets {
+		t.Errorf("unexpected pending packets size; got: %d, want: %d", len(server.pendingPackets), maxPendingPackets)
+	}
+	server.mu.Unlock()
+
+	writeDone := make(chan struct{})
+	go func() {
+		defer close(writeDone)
+
+		p := []byte{msgRequestSuccess, byte(65)}
+		// This write will block until KEX completes.
+		err := server.writePacket(p)
+		if err != nil {
+			t.Errorf("unexpected write error: %v", err)
+		}
+	}()
+
+	// Consume packets on the client side
+	readDone := make(chan bool)
+	go func() {
+		defer close(readDone)
+
+		for {
+			if _, err := client.readPacket(); err != nil {
+				if err != io.EOF {
+					t.Errorf("unexpected read error: %v", err)
+				}
+				break
+			}
+		}
+	}()
+
+	// Allow the client to reply to the KEX and so unblock the write goroutine.
+	trC.kexInitAllowed <- struct{}{}
+	<-trC.kexInitSent
+	<-writeDone
+	// Close the client to unblock the read goroutine.
+	client.Close()
+	<-readDone
+	server.Close()
+}
+
+func TestHandshakePendingPacketsError(t *testing.T) {
+	a, b := memPipe()
+
+	trS := &mockKeyingTransport{
+		packetConn:     a,
+		kexInitAllowed: make(chan struct{}, 2),
+		kexInitSent:    make(chan struct{}, 2),
+	}
+	// Allow the first KEX.
+	trS.kexInitAllowed <- struct{}{}
+
+	trC := &mockKeyingTransport{
+		packetConn:     b,
+		kexInitAllowed: make(chan struct{}, 2),
+		kexInitSent:    make(chan struct{}, 2),
+	}
+	// Allow the first KEX.
+	trC.kexInitAllowed <- struct{}{}
+
+	clientConf := &ClientConfig{
+		HostKeyCallback: InsecureIgnoreHostKey(),
+	}
+	clientConf.SetDefaults()
+
+	v := []byte("version")
+	client := newClientTransport(trC, v, v, clientConf, "addr", nil)
+
+	serverConf := &ServerConfig{}
+	serverConf.AddHostKey(testSigners["ecdsa"])
+	serverConf.AddHostKey(testSigners["rsa"])
+	serverConf.SetDefaults()
+	server := newServerTransport(trS, v, v, serverConf)
+
+	if err := server.waitSession(); err != nil {
+		t.Fatalf("server.waitSession: %v", err)
+	}
+	if err := client.waitSession(); err != nil {
+		t.Fatalf("client.waitSession: %v", err)
+	}
+
+	<-trC.kexInitSent
+	<-trS.kexInitSent
+
+	// Allow and request new KEX server side.
+	trS.kexInitAllowed <- struct{}{}
+	server.requestKeyExchange()
+	// Wait until the KEX init is sent.
+	<-trS.kexInitSent
+	// The client is not allowed to respond to the KEX, so writes will be
+	// blocked on the server side once the packets queue is full.
+	for i := 0; i < maxPendingPackets; i++ {
+		p := []byte{msgRequestSuccess, byte(i)}
+		if err := server.writePacket(p); err != nil {
+			t.Errorf("unexpected write error: %v", err)
+		}
+	}
+	// The packets queue is now full, the next write will block.
+	writeDone := make(chan struct{})
+	go func() {
+		defer close(writeDone)
+
+		p := []byte{msgRequestSuccess, byte(65)}
+		// This write will block until KEX completes.
+		err := server.writePacket(p)
+		if err != io.EOF {
+			t.Errorf("unexpected write error: %v", err)
+		}
+	}()
+
+	// Consume packets on the client side
+	readDone := make(chan bool)
+	go func() {
+		defer close(readDone)
+
+		for {
+			if _, err := client.readPacket(); err != nil {
+				if err != io.EOF {
+					t.Errorf("unexpected read error: %v", err)
+				}
+				break
+			}
+		}
+	}()
+
+	// Close the server to unblock the write after an error
+	server.Close()
+	<-writeDone
+	// Unblock the pending write and close the client to unblock the read
+	// goroutine.
+	trC.kexInitAllowed <- struct{}{}
+	client.Close()
+	<-readDone
+}
+
 func TestHandshakeRekeyDefault(t *testing.T) {
 	clientConf := &ClientConfig{
 		Config: Config{
-			Ciphers: []string{"aes128-ctr"},
+			Ciphers: []string{CipherAES128CTR},
 		},
 		HostKeyCallback: InsecureIgnoreHostKey(),
 	}
@@ -568,7 +788,7 @@ func TestHandshakeRekeyDefault(t *testing.T) {
 }
 
 func TestHandshakeAEADCipherNoMAC(t *testing.T) {
-	for _, cipher := range []string{chacha20Poly1305ID, gcm128CipherID} {
+	for _, cipher := range []string{CipherChaCha20Poly1305, CipherAES128GCM} {
 		checker := &syncChecker{
 			called: make(chan int, 1),
 		}
@@ -1019,3 +1239,128 @@ func TestStrictKEXMixed(t *testing.T) {
 		t.Fatalf("client.waitSession: %v", err)
 	}
 }
+
+func TestNegotiatedAlgorithms(t *testing.T) {
+	c1, c2, err := netPipe()
+	if err != nil {
+		t.Fatalf("netPipe: %v", err)
+	}
+	defer c1.Close()
+	defer c2.Close()
+
+	var serverAlgorithms NegotiatedAlgorithms
+
+	serverConf := &ServerConfig{
+		PasswordCallback: func(conn ConnMetadata, password []byte) (*Permissions, error) {
+			if algorithmConn, ok := conn.(AlgorithmsConnMetadata); ok {
+				serverAlgorithms = algorithmConn.Algorithms()
+				return &Permissions{}, nil
+			}
+			return nil, errors.New("server conn does not implement AlgorithmsConnMetadata")
+		},
+	}
+	serverConf.AddHostKey(testSigners["rsa"])
+	go NewServerConn(c1, serverConf)
+
+	clientConf := &ClientConfig{
+		User:            "test",
+		Auth:            []AuthMethod{Password("testpw")},
+		HostKeyCallback: FixedHostKey(testSigners["rsa"].PublicKey()),
+	}
+
+	if conn, _, _, err := NewClientConn(c2, "", clientConf); err != nil {
+		t.Fatal(err)
+	} else {
+		if algorithmConn, ok := conn.(AlgorithmsConnMetadata); ok {
+			clientAlgorithms := algorithmConn.Algorithms()
+			if clientAlgorithms.HostKey == "" {
+				t.Fatal("negotiated client host key is empty")
+			}
+			if clientAlgorithms.KeyExchange == "" {
+				t.Fatal("negotiated client KEX is empty")
+			}
+			if clientAlgorithms.Read.Cipher == "" {
+				t.Fatal("negotiated client read cipher is empty")
+			}
+			if clientAlgorithms.Write.Cipher == "" {
+				t.Fatal("negotiated client write cipher is empty")
+			}
+			if !reflect.DeepEqual(clientAlgorithms, serverAlgorithms) {
+				t.Fatalf("negotiated client algorithms: %+v differs from negotiated server algorithms: %+v",
+					clientAlgorithms, serverAlgorithms)
+			}
+		} else {
+			t.Fatal("client conn does not implement AlgorithmsConnMetadata")
+		}
+	}
+}
+
+func TestAlgorithmNegotiationError(t *testing.T) {
+	c1, c2, err := netPipe()
+	if err != nil {
+		t.Fatalf("netPipe: %v", err)
+	}
+	defer c1.Close()
+	defer c2.Close()
+
+	serverConf := &ServerConfig{
+		Config: Config{
+			Ciphers: []string{CipherAES128CTR, CipherAES256CTR},
+		},
+		PasswordCallback: func(conn ConnMetadata, password []byte) (*Permissions, error) {
+			return &Permissions{}, nil
+		},
+	}
+	serverConf.AddHostKey(testSigners["rsa"])
+
+	srvErrCh := make(chan error, 1)
+	go func() {
+		_, _, _, err := NewServerConn(c1, serverConf)
+		srvErrCh <- err
+	}()
+
+	clientConf := &ClientConfig{
+		Config: Config{
+			Ciphers: []string{CipherAES128GCM, CipherAES256GCM},
+		},
+		User:            "test",
+		Auth:            []AuthMethod{Password("testpw")},
+		HostKeyCallback: FixedHostKey(testSigners["rsa"].PublicKey()),
+	}
+
+	_, _, _, err = NewClientConn(c2, "", clientConf)
+	if err == nil {
+		t.Fatal("client connection succeded expected algorithm negotiation error")
+	}
+	var negotiationError *AlgorithmNegotiationError
+	if !errors.As(err, &negotiationError) {
+		t.Fatalf("expected algorithm negotiation error, got %v", err)
+	}
+	expectedErrorString := fmt.Sprintf("ssh: handshake failed: ssh: no common algorithm for client to server cipher; we offered: %v, peer offered: %v",
+		clientConf.Ciphers, serverConf.Ciphers)
+	if err.Error() != expectedErrorString {
+		t.Fatalf("expected error string %q, got %q", expectedErrorString, err.Error())
+	}
+	if !reflect.DeepEqual(negotiationError.RequestedAlgorithms, serverConf.Ciphers) {
+		t.Fatalf("expected requested algorithms %v, got %v", serverConf.Ciphers, negotiationError.RequestedAlgorithms)
+	}
+	if !reflect.DeepEqual(negotiationError.SupportedAlgorithms, clientConf.Ciphers) {
+		t.Fatalf("expected supported algorithms %v, got %v", clientConf.Ciphers, negotiationError.SupportedAlgorithms)
+	}
+	err = <-srvErrCh
+	negotiationError = nil
+	if !errors.As(err, &negotiationError) {
+		t.Fatalf("expected algorithm negotiation error, got %v", err)
+	}
+	expectedErrorString = fmt.Sprintf("ssh: no common algorithm for client to server cipher; we offered: %v, peer offered: %v",
+		serverConf.Ciphers, clientConf.Ciphers)
+	if err.Error() != expectedErrorString {
+		t.Fatalf("expected error string %q, got %q", expectedErrorString, err.Error())
+	}
+	if !reflect.DeepEqual(negotiationError.RequestedAlgorithms, clientConf.Ciphers) {
+		t.Fatalf("expected requested algorithms %v, got %v", clientConf.Ciphers, negotiationError.RequestedAlgorithms)
+	}
+	if !reflect.DeepEqual(negotiationError.SupportedAlgorithms, serverConf.Ciphers) {
+		t.Fatalf("expected supported algorithms %v, got %v", serverConf.Ciphers, negotiationError.SupportedAlgorithms)
+	}
+}

ssh/kex.go

@@ -9,7 +9,6 @@ import (
 	"crypto/ecdsa"
 	"crypto/elliptic"
 	"crypto/rand"
-	"crypto/subtle"
 	"encoding/binary"
 	"errors"
 	"fmt"
@@ -20,21 +19,18 @@ import (
 )
 
 const (
-	kexAlgoDH1SHA1                = "diffie-hellman-group1-sha1"
-	kexAlgoDH14SHA1               = "diffie-hellman-group14-sha1"
-	kexAlgoDH14SHA256             = "diffie-hellman-group14-sha256"
-	kexAlgoDH16SHA512             = "diffie-hellman-group16-sha512"
-	kexAlgoECDH256                = "ecdh-sha2-nistp256"
-	kexAlgoECDH384                = "ecdh-sha2-nistp384"
-	kexAlgoECDH521                = "ecdh-sha2-nistp521"
-	kexAlgoCurve25519SHA256LibSSH = "curve25519-sha256@libssh.org"
-	kexAlgoCurve25519SHA256       = "curve25519-sha256"
-
-	// For the following kex only the client half contains a production
-	// ready implementation. The server half only consists of a minimal
-	// implementation to satisfy the automated tests.
-	kexAlgoDHGEXSHA1   = "diffie-hellman-group-exchange-sha1"
-	kexAlgoDHGEXSHA256 = "diffie-hellman-group-exchange-sha256"
+	// This is the group called diffie-hellman-group1-sha1 in RFC 4253 and
+	// Oakley Group 2 in RFC 2409.
+	oakleyGroup2 = "FFFFFFFFFFFFFFFFC90FDAA22168C234C4C6628B80DC1CD129024E088A67CC74020BBEA63B139B22514A08798E3404DDEF9519B3CD3A431B302B0A6DF25F14374FE1356D6D51C245E485B576625E7EC6F44C42E9A637ED6B0BFF5CB6F406B7EDEE386BFB5A899FA5AE9F24117C4B1FE649286651ECE65381FFFFFFFFFFFFFFFF"
+	// This is the group called diffie-hellman-group14-sha1 in RFC 4253 and
+	// Oakley Group 14 in RFC 3526.
+	oakleyGroup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
+	// This is the group called diffie-hellman-group15-sha512 in RFC 8268 and
+	// Oakley Group 15 in RFC 3526.
+	oakleyGroup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
+	// This is the group called diffie-hellman-group16-sha512 in RFC 8268 and
+	// Oakley Group 16 in RFC 3526.
+	oakleyGroup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
 )
 
 // kexResult captures the outcome of a key exchange.
@@ -402,53 +398,47 @@ func ecHash(curve elliptic.Curve) crypto.Hash {
 var kexAlgoMap = map[string]kexAlgorithm{}
 
 func init() {
-	// This is the group called diffie-hellman-group1-sha1 in
-	// RFC 4253 and Oakley Group 2 in RFC 2409.
-	p, _ := new(big.Int).SetString("FFFFFFFFFFFFFFFFC90FDAA22168C234C4C6628B80DC1CD129024E088A67CC74020BBEA63B139B22514A08798E3404DDEF9519B3CD3A431B302B0A6DF25F14374FE1356D6D51C245E485B576625E7EC6F44C42E9A637ED6B0BFF5CB6F406B7EDEE386BFB5A899FA5AE9F24117C4B1FE649286651ECE65381FFFFFFFFFFFFFFFF", 16)
-	kexAlgoMap[kexAlgoDH1SHA1] = &dhGroup{
+	p, _ := new(big.Int).SetString(oakleyGroup2, 16)
+	kexAlgoMap[InsecureKeyExchangeDH1SHA1] = &dhGroup{
 		g:        new(big.Int).SetInt64(2),
 		p:        p,
 		pMinus1:  new(big.Int).Sub(p, bigOne),
 		hashFunc: crypto.SHA1,
 	}
 
-	// This are the groups called diffie-hellman-group14-sha1 and
-	// diffie-hellman-group14-sha256 in RFC 4253 and RFC 8268,
-	// and Oakley Group 14 in RFC 3526.
-	p, _ = new(big.Int).SetString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
+	p, _ = new(big.Int).SetString(oakleyGroup14, 16)
 	group14 := &dhGroup{
 		g:       new(big.Int).SetInt64(2),
 		p:       p,
 		pMinus1: new(big.Int).Sub(p, bigOne),
 	}
 
-	kexAlgoMap[kexAlgoDH14SHA1] = &dhGroup{
+	kexAlgoMap[InsecureKeyExchangeDH14SHA1] = &dhGroup{
 		g: group14.g, p: group14.p, pMinus1: group14.pMinus1,
 		hashFunc: crypto.SHA1,
 	}
-	kexAlgoMap[kexAlgoDH14SHA256] = &dhGroup{
+	kexAlgoMap[KeyExchangeDH14SHA256] = &dhGroup{
 		g: group14.g, p: group14.p, pMinus1: group14.pMinus1,
 		hashFunc: crypto.SHA256,
 	}
 
-	// This is the group called diffie-hellman-group16-sha512 in RFC
-	// 8268 and Oakley Group 16 in RFC 3526.
-	p, _ = new(big.Int).SetString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
+	p, _ = new(big.Int).SetString(oakleyGroup16, 16)
 
-	kexAlgoMap[kexAlgoDH16SHA512] = &dhGroup{
+	kexAlgoMap[KeyExchangeDH16SHA512] = &dhGroup{
 		g:        new(big.Int).SetInt64(2),
 		p:        p,
 		pMinus1:  new(big.Int).Sub(p, bigOne),
 		hashFunc: crypto.SHA512,
 	}
 
-	kexAlgoMap[kexAlgoECDH521] = &ecdh{elliptic.P521()}
-	kexAlgoMap[kexAlgoECDH384] = &ecdh{elliptic.P384()}
-	kexAlgoMap[kexAlgoECDH256] = &ecdh{elliptic.P256()}
-	kexAlgoMap[kexAlgoCurve25519SHA256] = &curve25519sha256{}
-	kexAlgoMap[kexAlgoCurve25519SHA256LibSSH] = &curve25519sha256{}
-	kexAlgoMap[kexAlgoDHGEXSHA1] = &dhGEXSHA{hashFunc: crypto.SHA1}
-	kexAlgoMap[kexAlgoDHGEXSHA256] = &dhGEXSHA{hashFunc: crypto.SHA256}
+	kexAlgoMap[KeyExchangeECDHP521] = &ecdh{elliptic.P521()}
+	kexAlgoMap[KeyExchangeECDHP384] = &ecdh{elliptic.P384()}
+	kexAlgoMap[KeyExchangeECDHP256] = &ecdh{elliptic.P256()}
+	kexAlgoMap[KeyExchangeCurve25519] = &curve25519sha256{}
+	kexAlgoMap[keyExchangeCurve25519LibSSH] = &curve25519sha256{}
+	kexAlgoMap[InsecureKeyExchangeDHGEXSHA1] = &dhGEXSHA{hashFunc: crypto.SHA1}
+	kexAlgoMap[KeyExchangeDHGEXSHA256] = &dhGEXSHA{hashFunc: crypto.SHA256}
+	kexAlgoMap[KeyExchangeMLKEM768X25519] = &mlkem768WithCurve25519sha256{}
 }
 
 // curve25519sha256 implements the curve25519-sha256 (formerly known as
@@ -464,15 +454,17 @@ func (kp *curve25519KeyPair) generate(rand io.Reader) error {
 	if _, err := io.ReadFull(rand, kp.priv[:]); err != nil {
 		return err
 	}
-	curve25519.ScalarBaseMult(&kp.pub, &kp.priv)
+	p, err := curve25519.X25519(kp.priv[:], curve25519.Basepoint)
+	if err != nil {
+		return fmt.Errorf("curve25519: %w", err)
+	}
+	if len(p) != 32 {
+		return fmt.Errorf("curve25519: internal error: X25519 returned %d bytes, expected 32", len(p))
+	}
+	copy(kp.pub[:], p)
 	return nil
 }
 
-// curve25519Zeros is just an array of 32 zero bytes so that we have something
-// convenient to compare against in order to reject curve25519 points with the
-// wrong order.
-var curve25519Zeros [32]byte
-
 func (kex *curve25519sha256) Client(c packetConn, rand io.Reader, magics *handshakeMagics) (*kexResult, error) {
 	var kp curve25519KeyPair
 	if err := kp.generate(rand); err != nil {
@@ -495,11 +487,9 @@ func (kex *curve25519sha256) Client(c packetConn, rand io.Reader, magics *handsh
 		return nil, errors.New("ssh: peer's curve25519 public value has wrong length")
 	}
 
-	var servPub, secret [32]byte
-	copy(servPub[:], reply.EphemeralPubKey)
-	curve25519.ScalarMult(&secret, &kp.priv, &servPub)
-	if subtle.ConstantTimeCompare(secret[:], curve25519Zeros[:]) == 1 {
-		return nil, errors.New("ssh: peer's curve25519 public value has wrong order")
+	secret, err := curve25519.X25519(kp.priv[:], reply.EphemeralPubKey)
+	if err != nil {
+		return nil, fmt.Errorf("ssh: peer's curve25519 public value is not valid: %w", err)
 	}
 
 	h := crypto.SHA256.New()
@@ -541,11 +531,9 @@ func (kex *curve25519sha256) Server(c packetConn, rand io.Reader, magics *handsh
 		return nil, err
 	}
 
-	var clientPub, secret [32]byte
-	copy(clientPub[:], kexInit.ClientPubKey)
-	curve25519.ScalarMult(&secret, &kp.priv, &clientPub)
-	if subtle.ConstantTimeCompare(secret[:], curve25519Zeros[:]) == 1 {
-		return nil, errors.New("ssh: peer's curve25519 public value has wrong order")
+	secret, err := curve25519.X25519(kp.priv[:], kexInit.ClientPubKey)
+	if err != nil {
+		return nil, fmt.Errorf("ssh: peer's curve25519 public value is not valid: %w", err)
 	}
 
 	hostKeyBytes := priv.PublicKey().Marshal()
@@ -601,9 +589,9 @@ const (
 func (gex *dhGEXSHA) Client(c packetConn, randSource io.Reader, magics *handshakeMagics) (*kexResult, error) {
 	// Send GexRequest
 	kexDHGexRequest := kexDHGexRequestMsg{
-		MinBits:      dhGroupExchangeMinimumBits,
-		PreferedBits: dhGroupExchangePreferredBits,
-		MaxBits:      dhGroupExchangeMaximumBits,
+		MinBits:       dhGroupExchangeMinimumBits,
+		PreferredBits: dhGroupExchangePreferredBits,
+		MaxBits:       dhGroupExchangeMaximumBits,
 	}
 	if err := c.writePacket(Marshal(&kexDHGexRequest)); err != nil {
 		return nil, err
@@ -690,9 +678,7 @@ func (gex *dhGEXSHA) Client(c packetConn, randSource io.Reader, magics *handshak
 }
 
 // Server half implementation of the Diffie Hellman Key Exchange with SHA1 and SHA256.
-//
-// This is a minimal implementation to satisfy the automated tests.
-func (gex dhGEXSHA) Server(c packetConn, randSource io.Reader, magics *handshakeMagics, priv AlgorithmSigner, algo string) (result *kexResult, err error) {
+func (gex *dhGEXSHA) Server(c packetConn, randSource io.Reader, magics *handshakeMagics, priv AlgorithmSigner, algo string) (result *kexResult, err error) {
 	// Receive GexRequest
 	packet, err := c.readPacket()
 	if err != nil {
@@ -702,13 +688,32 @@ func (gex dhGEXSHA) Server(c packetConn, randSource io.Reader, magics *handshake
 	if err = Unmarshal(packet, &kexDHGexRequest); err != nil {
 		return
 	}
+	// We check that the request received is valid and that the MaxBits
+	// requested are at least equal to our supported minimum. This is the same
+	// check done in OpenSSH:
+	// https://github.com/openssh/openssh-portable/blob/80a2f64b/kexgexs.c#L94
+	//
+	// Furthermore, we also check that the required MinBits are less than or
+	// equal to 4096 because we can use up to Oakley Group 16.
+	if kexDHGexRequest.MaxBits < kexDHGexRequest.MinBits || kexDHGexRequest.PreferredBits < kexDHGexRequest.MinBits ||
+		kexDHGexRequest.MaxBits < kexDHGexRequest.PreferredBits || kexDHGexRequest.MaxBits < dhGroupExchangeMinimumBits ||
+		kexDHGexRequest.MinBits > 4096 {
+		return nil, fmt.Errorf("ssh: DH GEX request out of range, min: %d, max: %d, preferred: %d", kexDHGexRequest.MinBits,
+			kexDHGexRequest.MaxBits, kexDHGexRequest.PreferredBits)
+	}
+
+	var p *big.Int
+	// We hardcode sending Oakley Group 14 (2048 bits), Oakley Group 15 (3072
+	// bits) or Oakley Group 16 (4096 bits), based on the requested max size.
+	if kexDHGexRequest.MaxBits < 3072 {
+		p, _ = new(big.Int).SetString(oakleyGroup14, 16)
+	} else if kexDHGexRequest.MaxBits < 4096 {
+		p, _ = new(big.Int).SetString(oakleyGroup15, 16)
+	} else {
+		p, _ = new(big.Int).SetString(oakleyGroup16, 16)
+	}
 
-	// Send GexGroup
-	// This is the group called diffie-hellman-group14-sha1 in RFC
-	// 4253 and Oakley Group 14 in RFC 3526.
-	p, _ := new(big.Int).SetString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
 	g := big.NewInt(2)
-
 	msg := &kexDHGexGroupMsg{
 		P: p,
 		G: g,
@@ -746,9 +751,9 @@ func (gex dhGEXSHA) Server(c packetConn, randSource io.Reader, magics *handshake
 	h := gex.hashFunc.New()
 	magics.write(h)
 	writeString(h, hostKeyBytes)
-	binary.Write(h, binary.BigEndian, uint32(dhGroupExchangeMinimumBits))
-	binary.Write(h, binary.BigEndian, uint32(dhGroupExchangePreferredBits))
-	binary.Write(h, binary.BigEndian, uint32(dhGroupExchangeMaximumBits))
+	binary.Write(h, binary.BigEndian, kexDHGexRequest.MinBits)
+	binary.Write(h, binary.BigEndian, kexDHGexRequest.PreferredBits)
+	binary.Write(h, binary.BigEndian, kexDHGexRequest.MaxBits)
 	writeInt(h, p)
 	writeInt(h, g)
 	writeInt(h, kexDHGexInit.X)

ssh/keys.go

@@ -36,14 +36,19 @@ import (
 // ClientConfig.HostKeyAlgorithms, Signature.Format, or as AlgorithmSigner
 // arguments.
 const (
-	KeyAlgoRSA        = "ssh-rsa"
-	KeyAlgoDSA        = "ssh-dss"
-	KeyAlgoECDSA256   = "ecdsa-sha2-nistp256"
-	KeyAlgoSKECDSA256 = "sk-ecdsa-sha2-nistp256@openssh.com"
-	KeyAlgoECDSA384   = "ecdsa-sha2-nistp384"
-	KeyAlgoECDSA521   = "ecdsa-sha2-nistp521"
-	KeyAlgoED25519    = "ssh-ed25519"
-	KeyAlgoSKED25519  = "sk-ssh-ed25519@openssh.com"
+	KeyAlgoRSA = "ssh-rsa"
+	// Deprecated: DSA is only supported at insecure key sizes, and was removed
+	// from major implementations.
+	KeyAlgoDSA = InsecureKeyAlgoDSA
+	// Deprecated: DSA is only supported at insecure key sizes, and was removed
+	// from major implementations.
+	InsecureKeyAlgoDSA = "ssh-dss"
+	KeyAlgoECDSA256    = "ecdsa-sha2-nistp256"
+	KeyAlgoSKECDSA256  = "sk-ecdsa-sha2-nistp256@openssh.com"
+	KeyAlgoECDSA384    = "ecdsa-sha2-nistp384"
+	KeyAlgoECDSA521    = "ecdsa-sha2-nistp521"
+	KeyAlgoED25519     = "ssh-ed25519"
+	KeyAlgoSKED25519   = "sk-ssh-ed25519@openssh.com"
 
 	// KeyAlgoRSASHA256 and KeyAlgoRSASHA512 are only public key algorithms, not
 	// public key formats, so they can't appear as a PublicKey.Type. The
@@ -67,7 +72,7 @@ func parsePubKey(in []byte, algo string) (pubKey PublicKey, rest []byte, err err
 	switch algo {
 	case KeyAlgoRSA:
 		return parseRSA(in)
-	case KeyAlgoDSA:
+	case InsecureKeyAlgoDSA:
 		return parseDSA(in)
 	case KeyAlgoECDSA256, KeyAlgoECDSA384, KeyAlgoECDSA521:
 		return parseECDSA(in)
@@ -77,7 +82,7 @@ func parsePubKey(in []byte, algo string) (pubKey PublicKey, rest []byte, err err
 		return parseED25519(in)
 	case KeyAlgoSKED25519:
 		return parseSKEd25519(in)
-	case CertAlgoRSAv01, CertAlgoDSAv01, CertAlgoECDSA256v01, CertAlgoECDSA384v01, CertAlgoECDSA521v01, CertAlgoSKECDSA256v01, CertAlgoED25519v01, CertAlgoSKED25519v01:
+	case CertAlgoRSAv01, InsecureCertAlgoDSAv01, CertAlgoECDSA256v01, CertAlgoECDSA384v01, CertAlgoECDSA521v01, CertAlgoSKECDSA256v01, CertAlgoED25519v01, CertAlgoSKED25519v01:
 		cert, err := parseCert(in, certKeyAlgoNames[algo])
 		if err != nil {
 			return nil, nil, err
@@ -268,7 +273,7 @@ func ParseAuthorizedKey(in []byte) (out PublicKey, comment string, options []str
 	return nil, "", nil, nil, errors.New("ssh: no key found")
 }
 
-// ParsePublicKey parses an SSH public key formatted for use in
+// ParsePublicKey parses an SSH public key or certificate formatted for use in
 // the SSH wire protocol according to RFC 4253, section 6.6.
 func ParsePublicKey(in []byte) (out PublicKey, err error) {
 	algo, in, ok := parseString(in)

ssh/keys_test.go

@@ -810,3 +810,30 @@ func TestCryptoPublicKey(t *testing.T) {
 		}
 	}
 }
+
+func TestParseCertWithCertSignatureKey(t *testing.T) {
+	certBytes := []byte(`-----BEGIN SSH CERTIFICATE-----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+-----END SSH CERTIFICATE-----
+	`)
+	block, _ := pem.Decode(certBytes)
+	if block == nil {
+		t.Fatal("invalid test certificate")
+	}
+
+	if _, err := ParsePublicKey(block.Bytes); err == nil {
+		t.Fatal("parsing an SSH certificate using another certificate as signature key succeeded; expected failure")
+	}
+}

ssh/knownhosts/knownhosts.go

@@ -302,8 +302,8 @@ func (k *KnownKey) String() string {
 // applications can offer an interactive prompt to the user.
 type KeyError struct {
 	// Want holds the accepted host keys. For each key algorithm,
-	// there can be one hostkey.  If Want is empty, the host is
-	// unknown. If Want is non-empty, there was a mismatch, which
+	// there can be multiple hostkeys.  If Want is empty, the host
+	// is unknown. If Want is non-empty, there was a mismatch, which
 	// can signify a MITM attack.
 	Want []KnownKey
 }
@@ -358,34 +358,20 @@ func (db *hostKeyDB) checkAddr(a addr, remoteKey ssh.PublicKey) error {
 	// is just a key for the IP address, but not for the
 	// hostname?
 
-	// Algorithm => key.
-	knownKeys := map[string]KnownKey{}
+	keyErr := &KeyError{}
+
 	for _, l := range db.lines {
-		if l.match(a) {
-			typ := l.knownKey.Key.Type()
-			if _, ok := knownKeys[typ]; !ok {
-				knownKeys[typ] = l.knownKey
-			}
+		if !l.match(a) {
+			continue
+		}
+
+		keyErr.Want = append(keyErr.Want, l.knownKey)
+		if keyEq(l.knownKey.Key, remoteKey) {
+			return nil
 		}
 	}
 
-	keyErr := &KeyError{}
-	for _, v := range knownKeys {
-		keyErr.Want = append(keyErr.Want, v)
-	}
-
-	// Unknown remote host.
-	if len(knownKeys) == 0 {
-		return keyErr
-	}
-
-	// If the remote host starts using a different, unknown key type, we
-	// also interpret that as a mismatch.
-	if known, ok := knownKeys[remoteKey.Type()]; !ok || !keyEq(known.Key, remoteKey) {
-		return keyErr
-	}
-
-	return nil
+	return keyErr
 }
 
 // The Read function parses file contents.
@@ -435,20 +421,26 @@ func New(files ...string) (ssh.HostKeyCallback, error) {
 	return certChecker.CheckHostKey, nil
 }
 
-// Normalize normalizes an address into the form used in known_hosts
+// Normalize normalizes an address into the form used in known_hosts. Supports
+// IPv4, hostnames, bracketed IPv6. Any other non-standard formats are returned
+// with minimal transformation.
 func Normalize(address string) string {
+	const defaultSSHPort = "22"
+
 	host, port, err := net.SplitHostPort(address)
 	if err != nil {
 		host = address
-		port = "22"
+		port = defaultSSHPort
 	}
-	entry := host
-	if port != "22" {
-		entry = "[" + entry + "]:" + port
-	} else if strings.Contains(host, ":") && !strings.HasPrefix(host, "[") {
-		entry = "[" + entry + "]"
+
+	if strings.HasPrefix(host, "[") && strings.HasSuffix(host, "]") {
+		host = host[1 : len(host)-1]
 	}
-	return entry
+
+	if port == defaultSSHPort {
+		return host
+	}
+	return "[" + host + "]:" + port
 }
 
 // Line returns a line to add append to the known_hosts files.

ssh/knownhosts/knownhosts_test.go

@@ -201,17 +201,6 @@ func TestHostNamePrecedence(t *testing.T) {
 	}
 }
 
-func TestDBOrderingPrecedenceKeyType(t *testing.T) {
-	str := fmt.Sprintf("server.org,%s %s\nserver.org,%s %s", testAddr, edKeyStr, testAddr, alternateEdKeyStr)
-	db := testDB(t, str)
-
-	if err := db.check("server.org:22", testAddr, alternateEdKey); err == nil {
-		t.Errorf("check succeeded")
-	} else if _, ok := err.(*KeyError); !ok {
-		t.Errorf("got %T, want *KeyError", err)
-	}
-}
-
 func TestNegate(t *testing.T) {
 	str := fmt.Sprintf("%s,!server.org %s", testAddr, edKeyStr)
 	db := testDB(t, str)
@@ -247,7 +236,7 @@ func TestLine(t *testing.T) {
 		"server.org":                             "server.org " + edKeyStr,
 		"server.org:22":                          "server.org " + edKeyStr,
 		"server.org:23":                          "[server.org]:23 " + edKeyStr,
-		"[c629:1ec4:102:304:102:304:102:304]:22": "[c629:1ec4:102:304:102:304:102:304] " + edKeyStr,
+		"[c629:1ec4:102:304:102:304:102:304]:22": "c629:1ec4:102:304:102:304:102:304 " + edKeyStr,
 		"[c629:1ec4:102:304:102:304:102:304]:23": "[c629:1ec4:102:304:102:304:102:304]:23 " + edKeyStr,
 	} {
 		if got := Line([]string{in}, edKey); got != want {
@@ -321,14 +310,25 @@ func testHostHash(t *testing.T, hostname, encoded string) {
 
 func TestNormalize(t *testing.T) {
 	for in, want := range map[string]string{
-		"127.0.0.1:22":             "127.0.0.1",
-		"[127.0.0.1]:22":           "127.0.0.1",
-		"[127.0.0.1]:23":           "[127.0.0.1]:23",
-		"127.0.0.1:23":             "[127.0.0.1]:23",
-		"[a.b.c]:22":               "a.b.c",
-		"[abcd:abcd:abcd:abcd]":    "[abcd:abcd:abcd:abcd]",
-		"[abcd:abcd:abcd:abcd]:22": "[abcd:abcd:abcd:abcd]",
-		"[abcd:abcd:abcd:abcd]:23": "[abcd:abcd:abcd:abcd]:23",
+		"127.0.0.1":                 "127.0.0.1",
+		"127.0.0.1:22":              "127.0.0.1",
+		"[127.0.0.1]:22":            "127.0.0.1",
+		"[127.0.0.1]:23":            "[127.0.0.1]:23",
+		"127.0.0.1:23":              "[127.0.0.1]:23",
+		"[a.b.c]:22":                "a.b.c",
+		"[a.b.c]:23":                "[a.b.c]:23",
+		"abcd::abcd:abcd:abcd":      "abcd::abcd:abcd:abcd",
+		"[abcd::abcd:abcd:abcd]":    "abcd::abcd:abcd:abcd",
+		"[abcd::abcd:abcd:abcd]:22": "abcd::abcd:abcd:abcd",
+		"[abcd::abcd:abcd:abcd]:23": "[abcd::abcd:abcd:abcd]:23",
+		"2001:db8::1":               "2001:db8::1",
+		"2001:db8::1:22":            "2001:db8::1:22",
+		"[2001:db8::1]:22":          "2001:db8::1",
+		"2001:db8::1:2200":          "2001:db8::1:2200",
+		"a.b.c.d.com:2200":          "[a.b.c.d.com]:2200",
+		"2001::db8:1":               "2001::db8:1",
+		"2001::db8:1:22":            "2001::db8:1:22",
+		"2001::db8:1:2200":          "2001::db8:1:2200",
 	} {
 		got := Normalize(in)
 		if got != want {
@@ -354,3 +354,16 @@ func TestHashedHostkeyCheck(t *testing.T) {
 		t.Errorf("got error %v, want %v", got, want)
 	}
 }
+
+func TestIssue36126(t *testing.T) {
+	str := fmt.Sprintf("server.org,%s %s\nserver.org,%s %s", testAddr, edKeyStr, testAddr, alternateEdKeyStr)
+	db := testDB(t, str)
+
+	if err := db.check("server.org:22", testAddr, edKey); err != nil {
+		t.Errorf("should have passed the check, got %v", err)
+	}
+
+	if err := db.check("server.org:22", testAddr, alternateEdKey); err != nil {
+		t.Errorf("should have passed the check, got %v", err)
+	}
+}

ssh/mac.go

@@ -47,22 +47,22 @@ func (t truncatingMAC) Size() int {
 func (t truncatingMAC) BlockSize() int { return t.hmac.BlockSize() }
 
 var macModes = map[string]*macMode{
-	"hmac-sha2-512-etm@openssh.com": {64, true, func(key []byte) hash.Hash {
+	HMACSHA512ETM: {64, true, func(key []byte) hash.Hash {
 		return hmac.New(sha512.New, key)
 	}},
-	"hmac-sha2-256-etm@openssh.com": {32, true, func(key []byte) hash.Hash {
+	HMACSHA256ETM: {32, true, func(key []byte) hash.Hash {
 		return hmac.New(sha256.New, key)
 	}},
-	"hmac-sha2-512": {64, false, func(key []byte) hash.Hash {
+	HMACSHA512: {64, false, func(key []byte) hash.Hash {
 		return hmac.New(sha512.New, key)
 	}},
-	"hmac-sha2-256": {32, false, func(key []byte) hash.Hash {
+	HMACSHA256: {32, false, func(key []byte) hash.Hash {
 		return hmac.New(sha256.New, key)
 	}},
-	"hmac-sha1": {20, false, func(key []byte) hash.Hash {
+	HMACSHA1: {20, false, func(key []byte) hash.Hash {
 		return hmac.New(sha1.New, key)
 	}},
-	"hmac-sha1-96": {20, false, func(key []byte) hash.Hash {
+	InsecureHMACSHA196: {20, false, func(key []byte) hash.Hash {
 		return truncatingMAC{12, hmac.New(sha1.New, key)}
 	}},
 }

ssh/messages.go

@@ -122,9 +122,9 @@ type kexDHGexReplyMsg struct {
 const msgKexDHGexRequest = 34
 
 type kexDHGexRequestMsg struct {
-	MinBits      uint32 `sshtype:"34"`
-	PreferedBits uint32
-	MaxBits      uint32
+	MinBits       uint32 `sshtype:"34"`
+	PreferredBits uint32
+	MaxBits       uint32
 }
 
 // See RFC 4253, section 10.
@@ -818,6 +818,8 @@ func decode(packet []byte) (interface{}, error) {
 		return new(userAuthSuccessMsg), nil
 	case msgUserAuthFailure:
 		msg = new(userAuthFailureMsg)
+	case msgUserAuthBanner:
+		msg = new(userAuthBannerMsg)
 	case msgUserAuthPubKeyOk:
 		msg = new(userAuthPubKeyOkMsg)
 	case msgGlobalRequest:

ssh/messages_test.go

@@ -206,6 +206,62 @@ func TestMarshalMultiTag(t *testing.T) {
 	}
 }
 
+func TestDecode(t *testing.T) {
+	rnd := rand.New(rand.NewSource(0))
+	kexInit := new(kexInitMsg).Generate(rnd, 10).Interface()
+	kexDHInit := new(kexDHInitMsg).Generate(rnd, 10).Interface()
+	kexDHReply := new(kexDHReplyMsg)
+	kexDHReply.Y = randomInt(rnd)
+	// Note: userAuthSuccessMsg can't be tested directly since it
+	// doesn't have a field for sshtype. So it's tested separately
+	// at the end.
+	decodeMessageTypes := []interface{}{
+		new(disconnectMsg),
+		new(serviceRequestMsg),
+		new(serviceAcceptMsg),
+		new(extInfoMsg),
+		kexInit,
+		kexDHInit,
+		kexDHReply,
+		new(userAuthRequestMsg),
+		new(userAuthFailureMsg),
+		new(userAuthBannerMsg),
+		new(userAuthPubKeyOkMsg),
+		new(globalRequestMsg),
+		new(globalRequestSuccessMsg),
+		new(globalRequestFailureMsg),
+		new(channelOpenMsg),
+		new(channelDataMsg),
+		new(channelOpenConfirmMsg),
+		new(channelOpenFailureMsg),
+		new(windowAdjustMsg),
+		new(channelEOFMsg),
+		new(channelCloseMsg),
+		new(channelRequestMsg),
+		new(channelRequestSuccessMsg),
+		new(channelRequestFailureMsg),
+		new(userAuthGSSAPIToken),
+		new(userAuthGSSAPIMIC),
+		new(userAuthGSSAPIErrTok),
+		new(userAuthGSSAPIError),
+	}
+	for _, msg := range decodeMessageTypes {
+		decoded, err := decode(Marshal(msg))
+		if err != nil {
+			t.Errorf("error decoding %T", msg)
+		} else if reflect.TypeOf(msg) != reflect.TypeOf(decoded) {
+			t.Errorf("error decoding %T, unexpected %T", msg, decoded)
+		}
+	}
+
+	userAuthSuccess, err := decode([]byte{msgUserAuthSuccess})
+	if err != nil {
+		t.Errorf("error decoding userAuthSuccessMsg")
+	} else if reflect.TypeOf(userAuthSuccess) != reflect.TypeOf((*userAuthSuccessMsg)(nil)) {
+		t.Errorf("error decoding userAuthSuccessMsg, unexpected %T", userAuthSuccess)
+	}
+}
+
 func randomBytes(out []byte, rand *rand.Rand) {
 	for i := 0; i < len(out); i++ {
 		out[i] = byte(rand.Int31())

ssh/mlkem.go

@@ -0,0 +1,168 @@
+// Copyright 2024 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package ssh
+
+import (
+	"crypto"
+	"crypto/mlkem"
+	"crypto/sha256"
+	"errors"
+	"fmt"
+	"io"
+
+	"golang.org/x/crypto/curve25519"
+)
+
+// mlkem768WithCurve25519sha256 implements the hybrid ML-KEM768 with
+// curve25519-sha256 key exchange method, as described by
+// draft-kampanakis-curdle-ssh-pq-ke-05 section 2.3.3.
+type mlkem768WithCurve25519sha256 struct{}
+
+func (kex *mlkem768WithCurve25519sha256) Client(c packetConn, rand io.Reader, magics *handshakeMagics) (*kexResult, error) {
+	var c25519kp curve25519KeyPair
+	if err := c25519kp.generate(rand); err != nil {
+		return nil, err
+	}
+
+	seed := make([]byte, mlkem.SeedSize)
+	if _, err := io.ReadFull(rand, seed); err != nil {
+		return nil, err
+	}
+
+	mlkemDk, err := mlkem.NewDecapsulationKey768(seed)
+	if err != nil {
+		return nil, err
+	}
+
+	hybridKey := append(mlkemDk.EncapsulationKey().Bytes(), c25519kp.pub[:]...)
+	if err := c.writePacket(Marshal(&kexECDHInitMsg{hybridKey})); err != nil {
+		return nil, err
+	}
+
+	packet, err := c.readPacket()
+	if err != nil {
+		return nil, err
+	}
+
+	var reply kexECDHReplyMsg
+	if err = Unmarshal(packet, &reply); err != nil {
+		return nil, err
+	}
+
+	if len(reply.EphemeralPubKey) != mlkem.CiphertextSize768+32 {
+		return nil, errors.New("ssh: peer's mlkem768x25519 public value has wrong length")
+	}
+
+	// Perform KEM decapsulate operation to obtain shared key from ML-KEM.
+	mlkem768Secret, err := mlkemDk.Decapsulate(reply.EphemeralPubKey[:mlkem.CiphertextSize768])
+	if err != nil {
+		return nil, err
+	}
+
+	// Complete Curve25519 ECDH to obtain its shared key.
+	c25519Secret, err := curve25519.X25519(c25519kp.priv[:], reply.EphemeralPubKey[mlkem.CiphertextSize768:])
+	if err != nil {
+		return nil, fmt.Errorf("ssh: peer's mlkem768x25519 public value is not valid: %w", err)
+	}
+	// Compute actual shared key.
+	h := sha256.New()
+	h.Write(mlkem768Secret)
+	h.Write(c25519Secret)
+	secret := h.Sum(nil)
+
+	h.Reset()
+	magics.write(h)
+	writeString(h, reply.HostKey)
+	writeString(h, hybridKey)
+	writeString(h, reply.EphemeralPubKey)
+
+	K := make([]byte, stringLength(len(secret)))
+	marshalString(K, secret)
+	h.Write(K)
+
+	return &kexResult{
+		H:         h.Sum(nil),
+		K:         K,
+		HostKey:   reply.HostKey,
+		Signature: reply.Signature,
+		Hash:      crypto.SHA256,
+	}, nil
+}
+
+func (kex *mlkem768WithCurve25519sha256) Server(c packetConn, rand io.Reader, magics *handshakeMagics, priv AlgorithmSigner, algo string) (*kexResult, error) {
+	packet, err := c.readPacket()
+	if err != nil {
+		return nil, err
+	}
+
+	var kexInit kexECDHInitMsg
+	if err = Unmarshal(packet, &kexInit); err != nil {
+		return nil, err
+	}
+
+	if len(kexInit.ClientPubKey) != mlkem.EncapsulationKeySize768+32 {
+		return nil, errors.New("ssh: peer's ML-KEM768/curve25519 public value has wrong length")
+	}
+
+	encapsulationKey, err := mlkem.NewEncapsulationKey768(kexInit.ClientPubKey[:mlkem.EncapsulationKeySize768])
+	if err != nil {
+		return nil, fmt.Errorf("ssh: peer's ML-KEM768 encapsulation key is not valid: %w", err)
+	}
+	// Perform KEM encapsulate operation to obtain ciphertext and shared key.
+	mlkem768Secret, mlkem768Ciphertext := encapsulationKey.Encapsulate()
+
+	// Perform server side of Curve25519 ECDH to obtain server public value and
+	// shared key.
+	var c25519kp curve25519KeyPair
+	if err := c25519kp.generate(rand); err != nil {
+		return nil, err
+	}
+	c25519Secret, err := curve25519.X25519(c25519kp.priv[:], kexInit.ClientPubKey[mlkem.EncapsulationKeySize768:])
+	if err != nil {
+		return nil, fmt.Errorf("ssh: peer's ML-KEM768/curve25519 public value is not valid: %w", err)
+	}
+	hybridKey := append(mlkem768Ciphertext, c25519kp.pub[:]...)
+
+	// Compute actual shared key.
+	h := sha256.New()
+	h.Write(mlkem768Secret)
+	h.Write(c25519Secret)
+	secret := h.Sum(nil)
+
+	hostKeyBytes := priv.PublicKey().Marshal()
+
+	h.Reset()
+	magics.write(h)
+	writeString(h, hostKeyBytes)
+	writeString(h, kexInit.ClientPubKey)
+	writeString(h, hybridKey)
+
+	K := make([]byte, stringLength(len(secret)))
+	marshalString(K, secret)
+	h.Write(K)
+
+	H := h.Sum(nil)
+
+	sig, err := signAndMarshal(priv, rand, H, algo)
+	if err != nil {
+		return nil, err
+	}
+
+	reply := kexECDHReplyMsg{
+		EphemeralPubKey: hybridKey,
+		HostKey:         hostKeyBytes,
+		Signature:       sig,
+	}
+	if err := c.writePacket(Marshal(&reply)); err != nil {
+		return nil, err
+	}
+	return &kexResult{
+		H:         H,
+		K:         K,
+		HostKey:   hostKeyBytes,
+		Signature: sig,
+		Hash:      crypto.SHA256,
+	}, nil
+}

ssh/server.go

@@ -59,6 +59,27 @@ type GSSAPIWithMICConfig struct {
 	Server GSSAPIServer
 }
 
+// SendAuthBanner implements [ServerPreAuthConn].
+func (s *connection) SendAuthBanner(msg string) error {
+	return s.transport.writePacket(Marshal(&userAuthBannerMsg{
+		Message: msg,
+	}))
+}
+
+func (*connection) unexportedMethodForFutureProofing() {}
+
+// ServerPreAuthConn is the interface available on an incoming server
+// connection before authentication has completed.
+type ServerPreAuthConn interface {
+	unexportedMethodForFutureProofing() // permits growing ServerPreAuthConn safely later, ala testing.TB
+
+	ConnMetadata
+
+	// SendAuthBanner sends a banner message to the client.
+	// It returns an error once the authentication phase has ended.
+	SendAuthBanner(string) error
+}
+
 // ServerConfig holds server specific configuration data.
 type ServerConfig struct {
 	// Config contains configuration shared between client and server.
@@ -118,6 +139,12 @@ type ServerConfig struct {
 	// attempts.
 	AuthLogCallback func(conn ConnMetadata, method string, err error)
 
+	// PreAuthConnCallback, if non-nil, is called upon receiving a new connection
+	// before any authentication has started. The provided ServerPreAuthConn
+	// can be used at any time before authentication is complete, including
+	// after this callback has returned.
+	PreAuthConnCallback func(ServerPreAuthConn)
+
 	// ServerVersion is the version identification string to announce in
 	// the public handshake.
 	// If empty, a reasonable default is used.
@@ -149,7 +176,7 @@ func (s *ServerConfig) AddHostKey(key Signer) {
 }
 
 // cachedPubKey contains the results of querying whether a public key is
-// acceptable for a user.
+// acceptable for a user. This is a FIFO cache.
 type cachedPubKey struct {
 	user       string
 	pubKeyData []byte
@@ -157,7 +184,13 @@ type cachedPubKey struct {
 	perms      *Permissions
 }
 
-const maxCachedPubKeys = 16
+// maxCachedPubKeys is the number of cache entries we store.
+//
+// Due to consistent misuse of the PublicKeyCallback API, we have reduced this
+// to 1, such that the only key in the cache is the most recently seen one. This
+// forces the behavior that the last call to PublicKeyCallback will always be
+// with the key that is used for authentication.
+const maxCachedPubKeys = 1
 
 // pubKeyCache caches tests for public keys.  Since SSH clients
 // will query whether a public key is acceptable before attempting to
@@ -179,9 +212,10 @@ func (c *pubKeyCache) get(user string, pubKeyData []byte) (cachedPubKey, bool) {
 
 // add adds the given tuple to the cache.
 func (c *pubKeyCache) add(candidate cachedPubKey) {
-	if len(c.keys) < maxCachedPubKeys {
-		c.keys = append(c.keys, candidate)
+	if len(c.keys) >= maxCachedPubKeys {
+		c.keys = c.keys[1:]
 	}
+	c.keys = append(c.keys, candidate)
 }
 
 // ServerConn is an authenticated SSH connection, as seen from the
@@ -209,22 +243,15 @@ func NewServerConn(c net.Conn, config *ServerConfig) (*ServerConn, <-chan NewCha
 		fullConf.MaxAuthTries = 6
 	}
 	if len(fullConf.PublicKeyAuthAlgorithms) == 0 {
-		fullConf.PublicKeyAuthAlgorithms = supportedPubKeyAuthAlgos
+		fullConf.PublicKeyAuthAlgorithms = defaultPubKeyAuthAlgos
 	} else {
 		for _, algo := range fullConf.PublicKeyAuthAlgorithms {
-			if !contains(supportedPubKeyAuthAlgos, algo) {
+			if !contains(SupportedAlgorithms().PublicKeyAuths, algo) && !contains(InsecureAlgorithms().PublicKeyAuths, algo) {
 				c.Close()
 				return nil, nil, nil, fmt.Errorf("ssh: unsupported public key authentication algorithm %s", algo)
 			}
 		}
 	}
-	// Check if the config contains any unsupported key exchanges
-	for _, kex := range fullConf.KeyExchanges {
-		if _, ok := serverForbiddenKexAlgos[kex]; ok {
-			c.Close()
-			return nil, nil, nil, fmt.Errorf("ssh: unsupported key exchange %s for server", kex)
-		}
-	}
 
 	s := &connection{
 		sshConn: sshConn{conn: c},
@@ -281,6 +308,7 @@ func (s *connection) serverHandshake(config *ServerConfig) (*Permissions, error)
 
 	// We just did the key change, so the session ID is established.
 	s.sessionID = s.transport.getSessionID()
+	s.algorithms = s.transport.getAlgorithms()
 
 	var packet []byte
 	if packet, err = s.transport.readPacket(); err != nil {
@@ -481,6 +509,10 @@ func (b *BannerError) Error() string {
 }
 
 func (s *connection) serverAuthenticate(config *ServerConfig) (*Permissions, error) {
+	if config.PreAuthConnCallback != nil {
+		config.PreAuthConnCallback(s)
+	}
+
 	sessionID := s.transport.getSessionID()
 	var cache pubKeyCache
 	var perms *Permissions
@@ -488,7 +520,7 @@ func (s *connection) serverAuthenticate(config *ServerConfig) (*Permissions, err
 	authFailures := 0
 	noneAuthCount := 0
 	var authErrs []error
-	var displayedBanner bool
+	var calledBannerCallback bool
 	partialSuccessReturned := false
 	// Set the initial authentication callbacks from the config. They can be
 	// changed if a PartialSuccessError is returned.
@@ -510,8 +542,8 @@ userAuthLoop:
 			if err := s.transport.writePacket(Marshal(discMsg)); err != nil {
 				return nil, err
 			}
-
-			return nil, discMsg
+			authErrs = append(authErrs, discMsg)
+			return nil, &ServerAuthError{Errors: authErrs}
 		}
 
 		var userAuthReq userAuthRequestMsg
@@ -535,14 +567,10 @@ userAuthLoop:
 
 		s.user = userAuthReq.User
 
-		if !displayedBanner && config.BannerCallback != nil {
-			displayedBanner = true
-			msg := config.BannerCallback(s)
-			if msg != "" {
-				bannerMsg := &userAuthBannerMsg{
-					Message: msg,
-				}
-				if err := s.transport.writePacket(Marshal(bannerMsg)); err != nil {
+		if !calledBannerCallback && config.BannerCallback != nil {
+			calledBannerCallback = true
+			if msg := config.BannerCallback(s); msg != "" {
+				if err := s.SendAuthBanner(msg); err != nil {
 					return nil, err
 				}
 			}
@@ -755,10 +783,7 @@ userAuthLoop:
 		var bannerErr *BannerError
 		if errors.As(authErr, &bannerErr) {
 			if bannerErr.Message != "" {
-				bannerMsg := &userAuthBannerMsg{
-					Message: bannerErr.Message,
-				}
-				if err := s.transport.writePacket(Marshal(bannerMsg)); err != nil {
+				if err := s.SendAuthBanner(bannerErr.Message); err != nil {
 					return nil, err
 				}
 			}

ssh/server_test.go

@@ -5,6 +5,7 @@
 package ssh
 
 import (
+	"bytes"
 	"errors"
 	"fmt"
 	"io"
@@ -211,7 +212,7 @@ func TestNewServerConnValidationErrors(t *testing.T) {
 
 	serverConf = &ServerConfig{
 		Config: Config{
-			KeyExchanges: []string{kexAlgoDHGEXSHA256},
+			KeyExchanges: []string{KeyExchangeDHGEXSHA256},
 		},
 	}
 	c = &markerConn{}
@@ -299,6 +300,140 @@ func TestBannerError(t *testing.T) {
 	}
 }
 
+func TestPublicKeyCallbackLastSeen(t *testing.T) {
+	var lastSeenKey PublicKey
+
+	c1, c2, err := netPipe()
+	if err != nil {
+		t.Fatalf("netPipe: %v", err)
+	}
+	defer c1.Close()
+	defer c2.Close()
+	serverConf := &ServerConfig{
+		PublicKeyCallback: func(conn ConnMetadata, key PublicKey) (*Permissions, error) {
+			lastSeenKey = key
+			fmt.Printf("seen %#v\n", key)
+			if _, ok := key.(*dsaPublicKey); !ok {
+				return nil, errors.New("nope")
+			}
+			return nil, nil
+		},
+	}
+	serverConf.AddHostKey(testSigners["ecdsap256"])
+
+	done := make(chan struct{})
+	go func() {
+		defer close(done)
+		NewServerConn(c1, serverConf)
+	}()
+
+	clientConf := ClientConfig{
+		User: "user",
+		Auth: []AuthMethod{
+			PublicKeys(testSigners["rsa"], testSigners["dsa"], testSigners["ed25519"]),
+		},
+		HostKeyCallback: InsecureIgnoreHostKey(),
+	}
+
+	_, _, _, err = NewClientConn(c2, "", &clientConf)
+	if err != nil {
+		t.Fatal(err)
+	}
+	<-done
+
+	expectedPublicKey := testSigners["dsa"].PublicKey().Marshal()
+	lastSeenMarshalled := lastSeenKey.Marshal()
+	if !bytes.Equal(lastSeenMarshalled, expectedPublicKey) {
+		t.Errorf("unexpected key: got %#v, want %#v", lastSeenKey, testSigners["dsa"].PublicKey())
+	}
+}
+
+func TestPreAuthConnAndBanners(t *testing.T) {
+	testDone := make(chan struct{})
+	defer close(testDone)
+
+	authConnc := make(chan ServerPreAuthConn, 1)
+	serverConfig := &ServerConfig{
+		PreAuthConnCallback: func(c ServerPreAuthConn) {
+			t.Logf("got ServerPreAuthConn: %v", c)
+			authConnc <- c // for use later in the test
+			for _, s := range []string{"hello1", "hello2"} {
+				if err := c.SendAuthBanner(s); err != nil {
+					t.Errorf("failed to send banner %q: %v", s, err)
+				}
+			}
+			// Now start a goroutine to spam SendAuthBanner in hopes
+			// of hitting a race.
+			go func() {
+				for {
+					select {
+					case <-testDone:
+						return
+					default:
+						if err := c.SendAuthBanner("attempted-race"); err != nil && err != errSendBannerPhase {
+							t.Errorf("unexpected error from SendAuthBanner: %v", err)
+						}
+						time.Sleep(5 * time.Millisecond)
+					}
+				}
+			}()
+		},
+		NoClientAuth: true,
+		NoClientAuthCallback: func(ConnMetadata) (*Permissions, error) {
+			t.Logf("got NoClientAuthCallback")
+			return &Permissions{}, nil
+		},
+	}
+	serverConfig.AddHostKey(testSigners["rsa"])
+
+	var banners []string
+	clientConfig := &ClientConfig{
+		User:            "test",
+		HostKeyCallback: InsecureIgnoreHostKey(),
+		BannerCallback: func(msg string) error {
+			if msg != "attempted-race" {
+				banners = append(banners, msg)
+			}
+			return nil
+		},
+	}
+
+	c1, c2, err := netPipe()
+	if err != nil {
+		t.Fatalf("netPipe: %v", err)
+	}
+	defer c1.Close()
+	defer c2.Close()
+	go newServer(c1, serverConfig)
+	c, _, _, err := NewClientConn(c2, "", clientConfig)
+	if err != nil {
+		t.Fatalf("client connection failed: %v", err)
+	}
+	defer c.Close()
+
+	wantBanners := []string{
+		"hello1",
+		"hello2",
+	}
+	if !reflect.DeepEqual(banners, wantBanners) {
+		t.Errorf("got banners:\n%q\nwant banners:\n%q", banners, wantBanners)
+	}
+
+	// Now that we're authenticated, verify that use of SendBanner
+	// is an error.
+	var bc ServerPreAuthConn
+	select {
+	case bc = <-authConnc:
+	default:
+		t.Fatal("expected ServerPreAuthConn")
+	}
+	if err := bc.SendAuthBanner("wrong-phase"); err == nil {
+		t.Error("unexpected success of SendAuthBanner after authentication")
+	} else if err != errSendBannerPhase {
+		t.Errorf("unexpected error: %v; want %v", err, errSendBannerPhase)
+	}
+}
+
 type markerConn struct {
 	closed uint32
 	used   uint32

ssh/tcpip.go

@@ -459,7 +459,7 @@ func (c *Client) dial(laddr string, lport int, raddr string, rport int) (Channel
 		return nil, err
 	}
 	go DiscardRequests(in)
-	return ch, err
+	return ch, nil
 }
 
 type tcpChan struct {