exp/ssh: cleanup client auth tests

This CL cleans up the client auth tests, making the
individual test body more manageable.

Also, adds tests for rsa and dsa key negotiation.

Finally, remove the package level use of the variable
strings, which avoids conflicting with the strings pkg.

R=gustav.paul, agl, n13m3y3r, rsc
CC=golang-dev
https://golang.org/cl/5447049

src/pkg/exp/ssh/client_auth_test.go

@@ -7,17 +7,20 @@ package ssh
 import (
 	"bytes"
 	"crypto"
-	"crypto/rand"
+	"crypto/dsa"
 	"crypto/rsa"
+	_ "crypto/sha1"
 	"crypto/x509"
 	"encoding/pem"
 	"errors"
 	"io"
 	"io/ioutil"
+	"math/big"
 	"testing"
 )
 
-const _pem = `-----BEGIN RSA PRIVATE KEY-----
+// private key for mock server
+const testServerPrivateKey = `-----BEGIN RSA PRIVATE KEY-----
 MIIEpAIBAAKCAQEA19lGVsTqIT5iiNYRgnoY1CwkbETW5cq+Rzk5v/kTlf31XpSU
 70HVWkbTERECjaYdXM2gGcbb+sxpq6GtXf1M3kVomycqhxwhPv4Cr6Xp4WT/jkFx
 9z+FFzpeodGJWjOH6L2H5uX1Cvr9EDdQp9t9/J32/qBFntY8GwoUI/y/1MSTmMiF
@@ -45,25 +48,32 @@ gqnBycHj6AhEycjda75cs+0zybZvN4x65KZHOGW/O/7OAWEcZP5TPb3zf9ned3Hl
 NsZoFj52ponUM6+99A2CmezFCN16c4mbA//luWF+k3VVqR6BpkrhKw==
 -----END RSA PRIVATE KEY-----`
 
-// reused internally by tests
+const testClientPrivateKey = `-----BEGIN RSA PRIVATE KEY-----
-var serverConfig = new(ServerConfig)
+MIIBOwIBAAJBALdGZxkXDAjsYk10ihwU6Id2KeILz1TAJuoq4tOgDWxEEGeTrcld
-
+r/ZwVaFzjWzxaf6zQIJbfaSEAhqD5yo72+sCAwEAAQJBAK8PEVU23Wj8mV0QjwcJ
-func init() {
+tZ4GcTUYQL7cF4+ezTCE9a1NrGnCP2RuQkHEKxuTVrxXt+6OF15/1/fuXnxKjmJC
-	if err := serverConfig.SetRSAPrivateKey([]byte(_pem)); err != nil {
+nxkCIQDaXvPPBi0c7vAxGwNY9726x01/dNbHCE0CBtcotobxpwIhANbbQbh3JHVW
-		panic("unable to set private key: " + err.Error())
+2haQh4fAG5mhesZKAGcxTyv4mQ7uMSQdAiAj+4dzMpJWdSzQ+qGHlHMIBvVHLkqB
-	}
+y2VdEyF7DPCZewIhAI7GOI/6LDIFOvtPo6Bj2nNmyQ1HU6k/LRtNIXi4c9NJAiAr
-}
+rrxx26itVhJmcvoUhOjwuzSlP2bE5VHAvkGB352YBg==
+-----END RSA PRIVATE KEY-----`
 
 // keychain implements the ClientPublickey interface
 type keychain struct {
-	keys []*rsa.PrivateKey
+	keys []interface{}
 }
 
 func (k *keychain) Key(i int) (interface{}, error) {
 	if i < 0 || i >= len(k.keys) {
 		return nil, nil
 	}
-	return k.keys[i].PublicKey, nil
+	switch key := k.keys[i].(type) {
+	case *rsa.PrivateKey:
+		return key.PublicKey, nil
+	case *dsa.PrivateKey:
+		return key.PublicKey, nil
+	}
+	panic("unknown key type")
 }
 
 func (k *keychain) Sign(i int, rand io.Reader, data []byte) (sig []byte, err error) {
@@ -71,7 +81,11 @@ func (k *keychain) Sign(i int, rand io.Reader, data []byte) (sig []byte, err err
 	h := hashFunc.New()
 	h.Write(data)
 	digest := h.Sum(nil)
-	return rsa.SignPKCS1v15(rand, k.keys[i], hashFunc, digest)
+	switch key := k.keys[i].(type) {
+	case *rsa.PrivateKey:
+		return rsa.SignPKCS1v15(rand, key, hashFunc, digest)
+	}
+	return nil, errors.New("unknown key type")
 }
 
 func (k *keychain) loadPEM(file string) error {
@@ -91,61 +105,6 @@ func (k *keychain) loadPEM(file string) error {
 	return nil
 }
 
-var pkey *rsa.PrivateKey
-
-func init() {
-	var err error
-	pkey, err = rsa.GenerateKey(rand.Reader, 512)
-	if err != nil {
-		panic("unable to generate public key")
-	}
-}
-
-func TestClientAuthPublickey(t *testing.T) {
-	k := new(keychain)
-	k.keys = append(k.keys, pkey)
-
-	serverConfig.PubKeyCallback = func(user, algo string, pubkey []byte) bool {
-		expected := []byte(serializePublickey(k.keys[0].PublicKey))
-		algoname := algoName(k.keys[0].PublicKey)
-		return user == "testuser" && algo == algoname && bytes.Equal(pubkey, expected)
-	}
-	serverConfig.PasswordCallback = nil
-
-	l, err := Listen("tcp", "127.0.0.1:0", serverConfig)
-	if err != nil {
-		t.Fatalf("unable to listen: %s", err)
-	}
-	defer l.Close()
-
-	done := make(chan bool, 1)
-	go func() {
-		c, err := l.Accept()
-		if err != nil {
-			t.Fatal(err)
-		}
-		defer c.Close()
-		if err := c.Handshake(); err != nil {
-			t.Error(err)
-		}
-		done <- true
-	}()
-
-	config := &ClientConfig{
-		User: "testuser",
-		Auth: []ClientAuth{
-			ClientAuthPublickey(k),
-		},
-	}
-
-	c, err := Dial("tcp", l.Addr().String(), config)
-	if err != nil {
-		t.Fatalf("unable to dial remote side: %s", err)
-	}
-	defer c.Close()
-	<-done
-}
-
 // password implements the ClientPassword interface
 type password string
 
@@ -153,96 +112,146 @@ func (p password) Password(user string) (string, error) {
 	return string(p), nil
 }
 
-func TestClientAuthPassword(t *testing.T) {
+// reused internally by tests
-	pw := password("tiger")
+var (
-
+	rsakey         *rsa.PrivateKey
-	serverConfig.PasswordCallback = func(user, pass string) bool {
+	dsakey         *dsa.PrivateKey
-		return user == "testuser" && pass == string(pw)
+	clientKeychain = new(keychain)
+	clientPassword = password("tiger")
+	serverConfig   = &ServerConfig{
+		PasswordCallback: func(user, pass string) bool {
+			return user == "testuser" && pass == string(clientPassword)
+		},
+		PubKeyCallback: func(user, algo string, pubkey []byte) bool {
+			key := clientKeychain.keys[0].(*rsa.PrivateKey).PublicKey
+			expected := []byte(serializePublickey(key))
+			algoname := algoName(key)
+			return user == "testuser" && algo == algoname && bytes.Equal(pubkey, expected)
+		},
 	}
-	serverConfig.PubKeyCallback = nil
+)
 
+func init() {
+	if err := serverConfig.SetRSAPrivateKey([]byte(testServerPrivateKey)); err != nil {
+		panic("unable to set private key: " + err.Error())
+	}
+
+	block, _ := pem.Decode([]byte(testClientPrivateKey))
+	rsakey, _ = x509.ParsePKCS1PrivateKey(block.Bytes)
+
+	clientKeychain.keys = append(clientKeychain.keys, rsakey)
+	dsakey = new(dsa.PrivateKey)
+	// taken from crypto/dsa/dsa_test.go
+	dsakey.P, _ = new(big.Int).SetString("A9B5B793FB4785793D246BAE77E8FF63CA52F442DA763C440259919FE1BC1D6065A9350637A04F75A2F039401D49F08E066C4D275A5A65DA5684BC563C14289D7AB8A67163BFBF79D85972619AD2CFF55AB0EE77A9002B0EF96293BDD0F42685EBB2C66C327079F6C98000FBCB79AACDE1BC6F9D5C7B1A97E3D9D54ED7951FEF", 16)
+	dsakey.Q, _ = new(big.Int).SetString("E1D3391245933D68A0714ED34BBCB7A1F422B9C1", 16)
+	dsakey.G, _ = new(big.Int).SetString("634364FC25248933D01D1993ECABD0657CC0CB2CEED7ED2E3E8AECDFCDC4A25C3B15E9E3B163ACA2984B5539181F3EFF1A5E8903D71D5B95DA4F27202B77D2C44B430BB53741A8D59A8F86887525C9F2A6A5980A195EAA7F2FF910064301DEF89D3AA213E1FAC7768D89365318E370AF54A112EFBA9246D9158386BA1B4EEFDA", 16)
+	dsakey.Y, _ = new(big.Int).SetString("32969E5780CFE1C849A1C276D7AEB4F38A23B591739AA2FE197349AEEBD31366AEE5EB7E6C6DDB7C57D02432B30DB5AA66D9884299FAA72568944E4EEDC92EA3FBC6F39F53412FBCC563208F7C15B737AC8910DBC2D9C9B8C001E72FDC40EB694AB1F06A5A2DBD18D9E36C66F31F566742F11EC0A52E9F7B89355C02FB5D32D2", 16)
+	dsakey.X, _ = new(big.Int).SetString("5078D4D29795CBE76D3AACFE48C9AF0BCDBEE91A", 16)
+}
+
+// newMockAuthServer creates a new Server bound to 
+// the loopback interface. The server exits after 
+// processing one handshake.
+func newMockAuthServer(t *testing.T) string {
 	l, err := Listen("tcp", "127.0.0.1:0", serverConfig)
 	if err != nil {
-		t.Fatalf("unable to listen: %s", err)
+		t.Fatalf("unable to newMockAuthServer: %s", err)
 	}
-	defer l.Close()
-
-	done := make(chan bool)
 	go func() {
+		defer l.Close()
 		c, err := l.Accept()
+		defer c.Close()
 		if err != nil {
-			t.Fatal(err)
+			t.Errorf("Unable to accept incoming connection: %v", err)
+			return
 		}
 		if err := c.Handshake(); err != nil {
-			t.Error(err)
+			// not Errorf because this is expected to
+			// fail for some tests.
+			t.Logf("Handshaking error: %v", err)
+			return
 		}
-		defer c.Close()
-		done <- true
 	}()
+	return l.Addr().String()
+}
 
+func TestClientAuthPublickey(t *testing.T) {
 	config := &ClientConfig{
 		User: "testuser",
 		Auth: []ClientAuth{
-			ClientAuthPassword(pw),
+			ClientAuthPublickey(clientKeychain),
 		},
 	}
-
+	c, err := Dial("tcp", newMockAuthServer(t), config)
-	c, err := Dial("tcp", l.Addr().String(), config)
 	if err != nil {
 		t.Fatalf("unable to dial remote side: %s", err)
 	}
-	defer c.Close()
+	c.Close()
-	<-done
 }
 
-func TestClientAuthPasswordAndPublickey(t *testing.T) {
+func TestClientAuthPassword(t *testing.T) {
-	pw := password("tiger")
+	config := &ClientConfig{
-
+		User: "testuser",
-	serverConfig.PasswordCallback = func(user, pass string) bool {
+		Auth: []ClientAuth{
-		return user == "testuser" && pass == string(pw)
+			ClientAuthPassword(clientPassword),
+		},
 	}
 
-	k := new(keychain)
+	c, err := Dial("tcp", newMockAuthServer(t), config)
-	k.keys = append(k.keys, pkey)
-
-	serverConfig.PubKeyCallback = func(user, algo string, pubkey []byte) bool {
-		expected := []byte(serializePublickey(k.keys[0].PublicKey))
-		algoname := algoName(k.keys[0].PublicKey)
-		return user == "testuser" && algo == algoname && bytes.Equal(pubkey, expected)
-	}
-
-	l, err := Listen("tcp", "127.0.0.1:0", serverConfig)
 	if err != nil {
-		t.Fatalf("unable to listen: %s", err)
+		t.Fatalf("unable to dial remote side: %s", err)
+	}
+	c.Close()
 }
-	defer l.Close()
-
-	done := make(chan bool)
-	go func() {
-		c, err := l.Accept()
-		if err != nil {
-			t.Fatal(err)
-		}
-		if err := c.Handshake(); err != nil {
-			t.Error(err)
-		}
-		defer c.Close()
-		done <- true
-	}()
 
+func TestClientAuthWrongPassword(t *testing.T) {
 	wrongPw := password("wrong")
 	config := &ClientConfig{
 		User: "testuser",
 		Auth: []ClientAuth{
 			ClientAuthPassword(wrongPw),
-			ClientAuthPublickey(k),
+			ClientAuthPublickey(clientKeychain),
 		},
 	}
 
-	c, err := Dial("tcp", l.Addr().String(), config)
+	c, err := Dial("tcp", newMockAuthServer(t), config)
 	if err != nil {
 		t.Fatalf("unable to dial remote side: %s", err)
 	}
-	defer c.Close()
+	c.Close()
-	<-done
+}
+
+// the mock server will only authenticate ssh-rsa keys
+func TestClientAuthInvalidPublickey(t *testing.T) {
+	kc := new(keychain)
+	kc.keys = append(kc.keys, dsakey)
+	config := &ClientConfig{
+		User: "testuser",
+		Auth: []ClientAuth{
+			ClientAuthPublickey(kc),
+		},
+	}
+
+	c, err := Dial("tcp", newMockAuthServer(t), config)
+	if err == nil {
+		c.Close()
+		t.Fatalf("dsa private key should not have authenticated with rsa public key")
+	}
+}
+
+// the client should authenticate with the second key
+func TestClientAuthRSAandDSA(t *testing.T) {
+	kc := new(keychain)
+	kc.keys = append(kc.keys, dsakey, rsakey)
+	config := &ClientConfig{
+		User: "testuser",
+		Auth: []ClientAuth{
+			ClientAuthPublickey(kc),
+		},
+	}
+	c, err := Dial("tcp", newMockAuthServer(t), config)
+	if err != nil {
+		t.Fatalf("client could not authenticate with rsa key: %v", err)
+	}
+	c.Close()
 }

src/pkg/exp/ssh/common_test.go

@@ -8,7 +8,8 @@ import (
 	"testing"
 )
 
-var strings = map[string]string{
+func TestSafeString(t *testing.T) {
+	strings := map[string]string{
 		"\x20\x0d\x0a":  "\x20\x0d\x0a",
 		"flibble":       "flibble",
 		"new\x20line":   "new\x20line",
@@ -16,7 +17,6 @@ var strings = map[string]string{
 		"\t\t\x10\r\n":  "\t\t \r\n",
 	}
 
-func TestSafeString(t *testing.T) {
 	for s, expected := range strings {
 		actual := safeString(s)
 		if expected != actual {