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x/crypto/ssh: add support for ed25519 keys

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Added support for parsing the "new" openssh private key format.
(ed25519 keys only in this format for now)

Signing and verifying functions now work with ed25519 keys.

ed25519 can now be accepted by the server to authenticate a client.

ed25519 can now be accepted by a client as a server host key.

Related documentation used:
https://www.ietf.org/archive/id/draft-bjh21-ssh-ed25519-02.txt

Change-Id: I84385f24d666fea08de21f980f78623f7bff8007
Reviewed-on: https://go-review.googlesource.com/22512
Reviewed-by: Han-Wen Nienhuys <hanwen@google.com>
Run-TryBot: Han-Wen Nienhuys <hanwen@google.com>
This commit is contained in:
Martin Garton
2016-05-12 13:28:31 +00:00
committed by Han-Wen Nienhuys
parent b76c864ef1
commit 1e61df8d9e
9 changed files with 178 additions and 12 deletions
Download Patch File Download Diff File Expand all files Collapse all files
ssh/agent/client.go
+1 -1
View File
@@ -188,7 +188,7 @@ func (k *Key) Marshal() []byte {
func (k *Key) Verify(data []byte, sig *ssh.Signature) error {
pubKey, err := ssh.ParsePublicKey(k.Blob)
if err != nil {
return fmt.Errorf("agent: bad public key")
return fmt.Errorf("agent: bad public key: %v", err)
}
return pubKey.Verify(data, sig)
}
ssh/certs.go
+3 -1
View File
@@ -22,6 +22,7 @@ const (
CertAlgoECDSA256v01 = "ecdsa-sha2-nistp256-cert-v01@openssh.com"
CertAlgoECDSA384v01 = "ecdsa-sha2-nistp384-cert-v01@openssh.com"
CertAlgoECDSA521v01 = "ecdsa-sha2-nistp521-cert-v01@openssh.com"
CertAlgoED25519v01 = "ssh-ed25519-cert-v01@openssh.com"
)
// Certificate types distinguish between host and user
@@ -401,6 +402,7 @@ var certAlgoNames = map[string]string{
KeyAlgoECDSA256: CertAlgoECDSA256v01,
KeyAlgoECDSA384: CertAlgoECDSA384v01,
KeyAlgoECDSA521: CertAlgoECDSA521v01,
KeyAlgoED25519: CertAlgoED25519v01,
}
// certToPrivAlgo returns the underlying algorithm for a certificate algorithm.
@@ -459,7 +461,7 @@ func (c *Certificate) Marshal() []byte {
func (c *Certificate) Type() string {
algo, ok := certAlgoNames[c.Key.Type()]
if !ok {
panic("unknown cert key type")
panic("unknown cert key type " + c.Key.Type())
}
return algo
}
ssh/common.go
+2
View File
@@ -48,6 +48,8 @@ var supportedHostKeyAlgos = []string{
KeyAlgoECDSA256, KeyAlgoECDSA384, KeyAlgoECDSA521,
KeyAlgoRSA, KeyAlgoDSA,
KeyAlgoED25519,
}
// supportedMACs specifies a default set of MAC algorithms in preference order.
ssh/keys.go
+128 -8
View File
@@ -20,6 +20,8 @@ import (
"io"
"math/big"
"strings"
"golang.org/x/crypto/ed25519"
)
// These constants represent the algorithm names for key types supported by this
@@ -30,6 +32,7 @@ const (
KeyAlgoECDSA256 = "ecdsa-sha2-nistp256"
KeyAlgoECDSA384 = "ecdsa-sha2-nistp384"
KeyAlgoECDSA521 = "ecdsa-sha2-nistp521"
KeyAlgoED25519 = "ssh-ed25519"
)
// parsePubKey parses a public key of the given algorithm.
@@ -42,14 +45,16 @@ func parsePubKey(in []byte, algo string) (pubKey PublicKey, rest []byte, err err
return parseDSA(in)
case KeyAlgoECDSA256, KeyAlgoECDSA384, KeyAlgoECDSA521:
return parseECDSA(in)
case CertAlgoRSAv01, CertAlgoDSAv01, CertAlgoECDSA256v01, CertAlgoECDSA384v01, CertAlgoECDSA521v01:
case KeyAlgoED25519:
return parseED25519(in)
case CertAlgoRSAv01, CertAlgoDSAv01, CertAlgoECDSA256v01, CertAlgoECDSA384v01, CertAlgoECDSA521v01, CertAlgoED25519v01:
cert, err := parseCert(in, certToPrivAlgo(algo))
if err != nil {
return nil, nil, err
}
return cert, nil, nil
}
return nil, nil, fmt.Errorf("ssh: unknown key algorithm: %v", err)
return nil, nil, fmt.Errorf("ssh: unknown key algorithm: %v", algo)
}
// parseAuthorizedKey parses a public key in OpenSSH authorized_keys format
@@ -459,6 +464,51 @@ func (key *ecdsaPublicKey) nistID() string {
panic("ssh: unsupported ecdsa key size")
}
type ed25519PublicKey ed25519.PublicKey
func (key ed25519PublicKey) Type() string {
return KeyAlgoED25519
}
func parseED25519(in []byte) (out PublicKey, rest []byte, err error) {
var w struct {
KeyBytes []byte
Rest []byte `ssh:"rest"`
}
if err := Unmarshal(in, &w); err != nil {
return nil, nil, err
}
key := ed25519.PublicKey(w.KeyBytes)
return (ed25519PublicKey)(key), w.Rest, nil
}
func (key ed25519PublicKey) Marshal() []byte {
w := struct {
Name string
KeyBytes []byte
}{
KeyAlgoED25519,
[]byte(key),
}
return Marshal(&w)
}
func (key ed25519PublicKey) Verify(b []byte, sig *Signature) error {
if sig.Format != key.Type() {
return fmt.Errorf("ssh: signature type %s for key type %s", sig.Format, key.Type())
}
edKey := (ed25519.PublicKey)(key)
if ok := ed25519.Verify(edKey, b, sig.Blob); !ok {
return errors.New("ssh: signature did not verify")
}
return nil
}
func supportedEllipticCurve(curve elliptic.Curve) bool {
return curve == elliptic.P256() || curve == elliptic.P384() || curve == elliptic.P521()
}
@@ -597,13 +647,19 @@ func (s *wrappedSigner) Sign(rand io.Reader, data []byte) (*Signature, error) {
hashFunc = crypto.SHA1
case *ecdsaPublicKey:
hashFunc = ecHash(key.Curve)
case ed25519PublicKey:
default:
return nil, fmt.Errorf("ssh: unsupported key type %T", key)
}
h := hashFunc.New()
h.Write(data)
digest := h.Sum(nil)
var digest []byte
if hashFunc != 0 {
h := hashFunc.New()
h.Write(data)
digest = h.Sum(nil)
} else {
digest = data
}
signature, err := s.signer.Sign(rand, digest, hashFunc)
if err != nil {
@@ -643,9 +699,9 @@ func (s *wrappedSigner) Sign(rand io.Reader, data []byte) (*Signature, error) {
}, nil
}
// NewPublicKey takes an *rsa.PublicKey, *dsa.PublicKey, *ecdsa.PublicKey or
// any other crypto.Signer and returns a corresponding Signer instance. ECDSA
// keys must use P-256, P-384 or P-521.
// NewPublicKey takes an *rsa.PublicKey, *dsa.PublicKey, *ecdsa.PublicKey,
// ed25519.PublicKey, or any other crypto.Signer and returns a corresponding
// Signer instance. ECDSA keys must use P-256, P-384 or P-521.
func NewPublicKey(key interface{}) (PublicKey, error) {
switch key := key.(type) {
case *rsa.PublicKey:
@@ -657,6 +713,8 @@ func NewPublicKey(key interface{}) (PublicKey, error) {
return (*ecdsaPublicKey)(key), nil
case *dsa.PublicKey:
return (*dsaPublicKey)(key), nil
case ed25519.PublicKey:
return (ed25519PublicKey)(key), nil
default:
return nil, fmt.Errorf("ssh: unsupported key type %T", key)
}
@@ -688,6 +746,8 @@ func ParseRawPrivateKey(pemBytes []byte) (interface{}, error) {
return x509.ParseECPrivateKey(block.Bytes)
case "DSA PRIVATE KEY":
return ParseDSAPrivateKey(block.Bytes)
case "OPENSSH PRIVATE KEY":
return parseOpenSSHPrivateKey(block.Bytes)
default:
return nil, fmt.Errorf("ssh: unsupported key type %q", block.Type)
}
@@ -724,3 +784,63 @@ func ParseDSAPrivateKey(der []byte) (*dsa.PrivateKey, error) {
X: k.Pub,
}, nil
}
// Implemented based on the documentation at
// https://github.com/openssh/openssh-portable/blob/master/PROTOCOL.key
func parseOpenSSHPrivateKey(key []byte) (*ed25519.PrivateKey, error) {
magic := append([]byte("openssh-key-v1"), 0)
if !bytes.Equal(magic, key[0:len(magic)]) {
return nil, errors.New("ssh: invalid openssh private key format")
}
remaining := key[len(magic):]
var w struct {
CipherName string
KdfName string
KdfOpts string
NumKeys uint32
PubKey []byte
PrivKeyBlock []byte
}
if err := Unmarshal(remaining, &w); err != nil {
return nil, err
}
pk1 := struct {
Check1 uint32
Check2 uint32
Keytype string
Pub []byte
Priv []byte
Comment string
Pad []byte `ssh:"rest"`
}{}
if err := Unmarshal(w.PrivKeyBlock, &pk1); err != nil {
return nil, err
}
if pk1.Check1 != pk1.Check2 {
return nil, errors.New("ssh: checkint mismatch")
}
// we only handle ed25519 keys currently
if pk1.Keytype != KeyAlgoED25519 {
return nil, errors.New("ssh: unhandled key type")
}
for i, b := range pk1.Pad {
if int(b) != i+1 {
return nil, errors.New("ssh: padding not as expected")
}
}
if len(pk1.Priv) != ed25519.PrivateKeySize {
return nil, errors.New("ssh: private key unexpected length")
}
pk := ed25519.PrivateKey(make([]byte, ed25519.PrivateKeySize))
copy(pk, pk1.Priv)
return &pk, nil
}
ssh/keys_test.go
+3
View File
@@ -17,6 +17,7 @@ import (
"strings"
"testing"
"golang.org/x/crypto/ed25519"
"golang.org/x/crypto/ssh/testdata"
)
@@ -28,6 +29,8 @@ func rawKey(pub PublicKey) interface{} {
return (*dsa.PublicKey)(k)
case *ecdsaPublicKey:
return (*ecdsa.PublicKey)(k)
case ed25519PublicKey:
return (ed25519.PublicKey)(k)
case *Certificate:
return k
}
ssh/server.go
+1 -1
View File
@@ -224,7 +224,7 @@ func (s *connection) serverHandshake(config *ServerConfig) (*Permissions, error)
func isAcceptableAlgo(algo string) bool {
switch algo {
case KeyAlgoRSA, KeyAlgoDSA, KeyAlgoECDSA256, KeyAlgoECDSA384, KeyAlgoECDSA521,
case KeyAlgoRSA, KeyAlgoDSA, KeyAlgoECDSA256, KeyAlgoECDSA384, KeyAlgoECDSA521, KeyAlgoED25519,
CertAlgoRSAv01, CertAlgoDSAv01, CertAlgoECDSA256v01, CertAlgoECDSA384v01, CertAlgoECDSA521v01:
return true
}
ssh/test/session_test.go
+25
View File
@@ -338,3 +338,28 @@ func TestKeyExchanges(t *testing.T) {
}
}
}
func TestClientAuthAlgorithms(t *testing.T) {
for _, key := range []string{
"rsa",
"dsa",
"ecdsa",
"ed25519",
} {
server := newServer(t)
conf := clientConfig()
conf.SetDefaults()
conf.Auth = []ssh.AuthMethod{
ssh.PublicKeys(testSigners[key]),
}
conn, err := server.TryDial(conf)
if err == nil {
conn.Close()
} else {
t.Errorf("failed for key %q", key)
}
server.Shutdown()
}
}
ssh/test/test_unix_test.go
+7 -1
View File
@@ -41,7 +41,7 @@ PermitRootLogin no
StrictModes no
RSAAuthentication yes
PubkeyAuthentication yes
AuthorizedKeysFile {{.Dir}}/id_user.pub
AuthorizedKeysFile {{.Dir}}/authorized_keys
TrustedUserCAKeys {{.Dir}}/id_ecdsa.pub
IgnoreRhosts yes
RhostsRSAAuthentication no
@@ -250,6 +250,12 @@ func newServer(t *testing.T) *server {
writeFile(filepath.Join(dir, filename+".pub"), ssh.MarshalAuthorizedKey(testPublicKeys[k]))
}
var authkeys bytes.Buffer
for k, _ := range testdata.PEMBytes {
authkeys.Write(ssh.MarshalAuthorizedKey(testPublicKeys[k]))
}
writeFile(filepath.Join(dir, "authorized_keys"), authkeys.Bytes())
return &server{
t: t,
configfile: f.Name(),
ssh/testdata/keys.go
Vendored
+8
View File
@@ -39,6 +39,14 @@ NDvRS0rjwt6lJGv7zPZoqDc65VfrK2aNyHx2PgFyzwrEOtuF57bu7pnvEIxpLTeM
z26i6XVMeYXAWZMTloMCQBbpGgEERQpeUknLBqUHhg/wXF6+lFA+vEGnkY+Dwab2
KCXFGd+SQ5GdUcEMe9isUH6DYj/6/yCDoFrXXmpQb+M=
-----END RSA PRIVATE KEY-----
`),
"ed25519": []byte(`-----BEGIN OPENSSH PRIVATE KEY-----
b3BlbnNzaC1rZXktdjEAAAAABG5vbmUAAAAEbm9uZQAAAAAAAAABAAAAMwAAAAtzc2gtZW
QyNTUxOQAAACA+3f7hS7g5UWwXOGVTrMfhmxyrjqz7Sxxbx7I1j8DvvwAAAJhAFfkOQBX5
DgAAAAtzc2gtZWQyNTUxOQAAACA+3f7hS7g5UWwXOGVTrMfhmxyrjqz7Sxxbx7I1j8Dvvw
AAAEAaYmXltfW6nhRo3iWGglRB48lYq0z0Q3I3KyrdutEr6j7d/uFLuDlRbBc4ZVOsx+Gb
HKuOrPtLHFvHsjWPwO+/AAAAE2dhcnRvbm1AZ2FydG9ubS14cHMBAg==
-----END OPENSSH PRIVATE KEY-----
`),
"user": []byte(`-----BEGIN EC PRIVATE KEY-----
MHcCAQEEILYCAeq8f7V4vSSypRw7pxy8yz3V5W4qg8kSC3zJhqpQoAoGCCqGSM49