x/crypto/ssh: support more keytypes in the agent.

This allows the golang ssh-agent to support the full suite of keys
the library accepts.

Currently constraints are ignored.

Change-Id: I7d48c78e9a355582eb54788571a483a736c3d3ef
Reviewed-on: https://go-review.googlesource.com/21536
Reviewed-by: Han-Wen Nienhuys <hanwen@google.com>
Run-TryBot: Han-Wen Nienhuys <hanwen@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

ssh/agent/server_test.go

@@ -5,6 +5,9 @@
 package agent
 
 import (
+	"crypto"
+	"crypto/rand"
+	"fmt"
 	"testing"
 
 	"golang.org/x/crypto/ssh"
@@ -107,3 +110,77 @@ func testV1ProtocolMessages(t *testing.T, c *client) {
 		t.Fatalf("invalid remove all response: %#v", reply)
 	}
 }
+
+func verifyKey(sshAgent Agent) error {
+	keys, err := sshAgent.List()
+	if err != nil {
+		return fmt.Errorf("listing keys: %v", err)
+	}
+
+	if len(keys) != 1 {
+		return fmt.Errorf("bad number of keys found. expected 1, got %d", len(keys))
+	}
+
+	buf := make([]byte, 128)
+	if _, err := rand.Read(buf); err != nil {
+		return fmt.Errorf("rand: %v", err)
+	}
+
+	sig, err := sshAgent.Sign(keys[0], buf)
+	if err != nil {
+		return fmt.Errorf("sign: %v", err)
+	}
+
+	if err := keys[0].Verify(buf, sig); err != nil {
+		return fmt.Errorf("verify: %v", err)
+	}
+	return nil
+}
+
+func addKeyToAgent(key crypto.PrivateKey) error {
+	sshAgent := NewKeyring()
+	if err := sshAgent.Add(AddedKey{PrivateKey: key}); err != nil {
+		return fmt.Errorf("add: %v", err)
+	}
+	return verifyKey(sshAgent)
+}
+
+func TestKeyTypes(t *testing.T) {
+	for k, v := range testPrivateKeys {
+		if err := addKeyToAgent(v); err != nil {
+			t.Errorf("error adding key type %s, %v", k, err)
+		}
+	}
+}
+
+func addCertToAgent(key crypto.PrivateKey, cert *ssh.Certificate) error {
+	sshAgent := NewKeyring()
+	if err := sshAgent.Add(AddedKey{PrivateKey: key, Certificate: cert}); err != nil {
+		return fmt.Errorf("add: %v", err)
+	}
+	return verifyKey(sshAgent)
+}
+
+func TestCertTypes(t *testing.T) {
+	for keyType, key := range testPublicKeys {
+		cert := &ssh.Certificate{
+			ValidPrincipals: []string{"gopher1"},
+			ValidAfter:      0,
+			ValidBefore:     ssh.CertTimeInfinity,
+			Key:             key,
+			Serial:          1,
+			CertType:        ssh.UserCert,
+			SignatureKey:    testPublicKeys["rsa"],
+			Permissions: ssh.Permissions{
+				CriticalOptions: map[string]string{},
+				Extensions:      map[string]string{},
+			},
+		}
+		if err := cert.SignCert(rand.Reader, testSigners["rsa"]); err != nil {
+			t.Fatalf("signcert: %v", err)
+		}
+		if err := addCertToAgent(testPrivateKeys[keyType], cert); err != nil {
+			t.Fatalf("%v", err)
+		}
+	}
+}