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// Copyright 2013 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 (
"bytes"
"crypto/rand"
"errors"
"fmt"
"io"
"net"
"reflect"
"runtime"
"strings"
"sync"
"testing"
)
type testChecker struct {
calls []string
}
func (t *testChecker) Check(dialAddr string, addr net.Addr, key PublicKey) error {
if dialAddr == "bad" {
return fmt.Errorf("dialAddr is bad")
}
if tcpAddr, ok := addr.(*net.TCPAddr); !ok || tcpAddr == nil {
return fmt.Errorf("testChecker: got %T want *net.TCPAddr", addr)
}
t.calls = append(t.calls, fmt.Sprintf("%s %v %s %x", dialAddr, addr, key.Type(), key.Marshal()))
return nil
}
// netPipe is analogous to net.Pipe, but it uses a real net.Conn, and
// therefore is buffered (net.Pipe deadlocks if both sides start with
// a write.)
func netPipe() (net.Conn, net.Conn, error) {
listener, err := net.Listen("tcp", "127.0.0.1:0")
if err != nil {
listener, err = net.Listen("tcp", "[::1]:0")
if err != nil {
return nil, nil, err
}
}
defer listener.Close()
c1, err := net.Dial("tcp", listener.Addr().String())
if err != nil {
return nil, nil, err
}
c2, err := listener.Accept()
if err != nil {
c1.Close()
return nil, nil, err
}
return c1, c2, nil
}
// noiseTransport inserts ignore messages to check that the read loop
// and the key exchange filters out these messages.
type noiseTransport struct {
keyingTransport
}
func (t *noiseTransport) writePacket(p []byte) error {
ignore := []byte{msgIgnore}
if err := t.keyingTransport.writePacket(ignore); err != nil {
return err
}
debug := []byte{msgDebug, 1, 2, 3}
if err := t.keyingTransport.writePacket(debug); err != nil {
return err
}
return t.keyingTransport.writePacket(p)
}
func addNoiseTransport(t keyingTransport) keyingTransport {
return &noiseTransport{t}
}
// handshakePair creates two handshakeTransports connected with each
// other. If the noise argument is true, both transports will try to
// confuse the other side by sending ignore and debug messages.
func handshakePair(clientConf *ClientConfig, addr string, noise bool) (client *handshakeTransport, server *handshakeTransport, err error) {
a, b, err := netPipe()
if err != nil {
return nil, nil, err
}
var trC, trS keyingTransport
trC = newTransport(a, rand.Reader, true)
trS = newTransport(b, rand.Reader, false)
if noise {
trC = addNoiseTransport(trC)
trS = addNoiseTransport(trS)
}
clientConf.SetDefaults()
v := []byte("version")
client = newClientTransport(trC, v, v, clientConf, addr, a.RemoteAddr())
serverConf := &ServerConfig{}
serverConf.AddHostKey(testSigners["ecdsa"])
serverConf.AddHostKey(testSigners["rsa"])
serverConf.SetDefaults()
server = newServerTransport(trS, v, v, serverConf)
if err := server.waitSession(); err != nil {
return nil, nil, fmt.Errorf("server.waitSession: %v", err)
}
if err := client.waitSession(); err != nil {
return nil, nil, fmt.Errorf("client.waitSession: %v", err)
}
return client, server, nil
}
func TestHandshakeBasic(t *testing.T) {
if runtime.GOOS == "plan9" {
t.Skip("see golang.org/issue/7237")
}
checker := &syncChecker{
waitCall: make(chan int, 10),
called: make(chan int, 10),
}
checker.waitCall <- 1
trC, trS, err := handshakePair(&ClientConfig{HostKeyCallback: checker.Check}, "addr", false)
if err != nil {
t.Fatalf("handshakePair: %v", err)
}
defer trC.Close()
defer trS.Close()
// Let first kex complete normally.
<-checker.called
clientDone := make(chan int, 0)
gotHalf := make(chan int, 0)
const N = 20
go func() {
defer close(clientDone)
// Client writes a bunch of stuff, and does a key
// change in the middle. This should not confuse the
// handshake in progress. We do this twice, so we test
// that the packet buffer is reset correctly.
for i := 0; i < N; i++ {
p := []byte{msgRequestSuccess, byte(i)}
if err := trC.writePacket(p); err != nil {
t.Fatalf("sendPacket: %v", err)
}
if (i % 10) == 5 {
<-gotHalf
// halfway through, we request a key change.
trC.requestKeyExchange()
// Wait until we can be sure the key
// change has really started before we
// write more.
<-checker.called
}
if (i % 10) == 7 {
// write some packets until the kex
// completes, to test buffering of
// packets.
checker.waitCall <- 1
}
}
}()
// Server checks that client messages come in cleanly
i := 0
err = nil
for ; i < N; i++ {
var p []byte
p, err = trS.readPacket()
if err != nil {
break
}
if (i % 10) == 5 {
gotHalf <- 1
}
want := []byte{msgRequestSuccess, byte(i)}
if bytes.Compare(p, want) != 0 {
t.Errorf("message %d: got %v, want %v", i, p, want)
}
}
<-clientDone
if err != nil && err != io.EOF {
t.Fatalf("server error: %v", err)
}
if i != N {
t.Errorf("received %d messages, want 10.", i)
}
close(checker.called)
if _, ok := <-checker.called; ok {
// If all went well, we registered exactly 2 key changes: one
// that establishes the session, and one that we requested
// additionally.
t.Fatalf("got another host key checks after 2 handshakes")
}
}
func TestForceFirstKex(t *testing.T) {
// like handshakePair, but must access the keyingTransport.
checker := &testChecker{}
clientConf := &ClientConfig{HostKeyCallback: checker.Check}
a, b, err := netPipe()
if err != nil {
t.Fatalf("netPipe: %v", err)
}
var trC, trS keyingTransport
trC = newTransport(a, rand.Reader, true)
// This is the disallowed packet:
trC.writePacket(Marshal(&serviceRequestMsg{serviceUserAuth}))
// Rest of the setup.
trS = newTransport(b, rand.Reader, false)
clientConf.SetDefaults()
v := []byte("version")
client := newClientTransport(trC, v, v, clientConf, "addr", a.RemoteAddr())
serverConf := &ServerConfig{}
serverConf.AddHostKey(testSigners["ecdsa"])
serverConf.AddHostKey(testSigners["rsa"])
serverConf.SetDefaults()
server := newServerTransport(trS, v, v, serverConf)
defer client.Close()
defer server.Close()
// We setup the initial key exchange, but the remote side
// tries to send serviceRequestMsg in cleartext, which is
// disallowed.
if err := server.waitSession(); err == nil {
t.Errorf("server first kex init should reject unexpected packet")
}
}
func TestHandshakeAutoRekeyWrite(t *testing.T) {
checker := &syncChecker{
called: make(chan int, 10),
waitCall: nil,
}
clientConf := &ClientConfig{HostKeyCallback: checker.Check}
clientConf.RekeyThreshold = 500
trC, trS, err := handshakePair(clientConf, "addr", false)
if err != nil {
t.Fatalf("handshakePair: %v", err)
}
defer trC.Close()
defer trS.Close()
input := make([]byte, 251)
input[0] = msgRequestSuccess
done := make(chan int, 1)
const numPacket = 5
go func() {
defer close(done)
j := 0
for ; j < numPacket; j++ {
if p, err := trS.readPacket(); err != nil {
break
} else if !bytes.Equal(input, p) {
t.Errorf("got packet type %d, want %d", p[0], input[0])
}
}
if j != numPacket {
t.Errorf("got %d, want 5 messages", j)
}
}()
<-checker.called
for i := 0; i < numPacket; i++ {
p := make([]byte, len(input))
copy(p, input)
if err := trC.writePacket(p); err != nil {
t.Errorf("writePacket: %v", err)
}
if i == 2 {
// Make sure the kex is in progress.
<-checker.called
}
}
<-done
}
type syncChecker struct {
waitCall chan int
called chan int
}
func (c *syncChecker) Check(dialAddr string, addr net.Addr, key PublicKey) error {
c.called <- 1
if c.waitCall != nil {
<-c.waitCall
}
return nil
}
func TestHandshakeAutoRekeyRead(t *testing.T) {
sync := &syncChecker{
called: make(chan int, 2),
waitCall: nil,
}
clientConf := &ClientConfig{
HostKeyCallback: sync.Check,
}
clientConf.RekeyThreshold = 500
trC, trS, err := handshakePair(clientConf, "addr", false)
if err != nil {
t.Fatalf("handshakePair: %v", err)
}
defer trC.Close()
defer trS.Close()
packet := make([]byte, 501)
packet[0] = msgRequestSuccess
if err := trS.writePacket(packet); err != nil {
t.Fatalf("writePacket: %v", err)
}
// While we read out the packet, a key change will be
// initiated.
done := make(chan int, 1)
go func() {
defer close(done)
if _, err := trC.readPacket(); err != nil {
t.Fatalf("readPacket(client): %v", err)
}
}()
<-done
<-sync.called
}
// errorKeyingTransport generates errors after a given number of
// read/write operations.
type errorKeyingTransport struct {
packetConn
readLeft, writeLeft int
}
func (n *errorKeyingTransport) prepareKeyChange(*algorithms, *kexResult) error {
return nil
}
func (n *errorKeyingTransport) getSessionID() []byte {
return nil
}
func (n *errorKeyingTransport) writePacket(packet []byte) error {
if n.writeLeft == 0 {
n.Close()
return errors.New("barf")
}
n.writeLeft--
return n.packetConn.writePacket(packet)
}
func (n *errorKeyingTransport) readPacket() ([]byte, error) {
if n.readLeft == 0 {
n.Close()
return nil, errors.New("barf")
}
n.readLeft--
return n.packetConn.readPacket()
}
func TestHandshakeErrorHandlingRead(t *testing.T) {
for i := 0; i < 20; i++ {
testHandshakeErrorHandlingN(t, i, -1, false)
}
}
func TestHandshakeErrorHandlingWrite(t *testing.T) {
for i := 0; i < 20; i++ {
testHandshakeErrorHandlingN(t, -1, i, false)
}
}
func TestHandshakeErrorHandlingReadCoupled(t *testing.T) {
for i := 0; i < 20; i++ {
testHandshakeErrorHandlingN(t, i, -1, true)
}
}
func TestHandshakeErrorHandlingWriteCoupled(t *testing.T) {
for i := 0; i < 20; i++ {
testHandshakeErrorHandlingN(t, -1, i, true)
}
}
// testHandshakeErrorHandlingN runs handshakes, injecting errors. If
// handshakeTransport deadlocks, the go runtime will detect it and
// panic.
func testHandshakeErrorHandlingN(t *testing.T, readLimit, writeLimit int, coupled bool) {
if runtime.GOOS == "js" && runtime.GOARCH == "wasm" {
t.Skip("skipping on js/wasm; see golang.org/issue/32840")
}
msg := Marshal(&serviceRequestMsg{strings.Repeat("x", int(minRekeyThreshold)/4)})
a, b := memPipe()
defer a.Close()
defer b.Close()
key := testSigners["ecdsa"]
serverConf := Config{RekeyThreshold: minRekeyThreshold}
serverConf.SetDefaults()
serverConn := newHandshakeTransport(&errorKeyingTransport{a, readLimit, writeLimit}, &serverConf, []byte{'a'}, []byte{'b'})
serverConn.hostKeys = []Signer{key}
go serverConn.readLoop()
go serverConn.kexLoop()
clientConf := Config{RekeyThreshold: 10 * minRekeyThreshold}
clientConf.SetDefaults()
clientConn := newHandshakeTransport(&errorKeyingTransport{b, -1, -1}, &clientConf, []byte{'a'}, []byte{'b'})
clientConn.hostKeyAlgorithms = []string{key.PublicKey().Type()}
clientConn.hostKeyCallback = InsecureIgnoreHostKey()
go clientConn.readLoop()
go clientConn.kexLoop()
var wg sync.WaitGroup
for _, hs := range []packetConn{serverConn, clientConn} {
if !coupled {
wg.Add(2)
go func(c packetConn) {
for i := 0; ; i++ {
str := fmt.Sprintf("%08x", i) + strings.Repeat("x", int(minRekeyThreshold)/4-8)
err := c.writePacket(Marshal(&serviceRequestMsg{str}))
if err != nil {
break
}
}
wg.Done()
c.Close()
}(hs)
go func(c packetConn) {
for {
_, err := c.readPacket()
if err != nil {
break
}
}
wg.Done()
}(hs)
} else {
wg.Add(1)
go func(c packetConn) {
for {
_, err := c.readPacket()
if err != nil {
break
}
if err := c.writePacket(msg); err != nil {
break
}
}
wg.Done()
}(hs)
}
}
wg.Wait()
}
func TestDisconnect(t *testing.T) {
if runtime.GOOS == "plan9" {
t.Skip("see golang.org/issue/7237")
}
checker := &testChecker{}
trC, trS, err := handshakePair(&ClientConfig{HostKeyCallback: checker.Check}, "addr", false)
if err != nil {
t.Fatalf("handshakePair: %v", err)
}
defer trC.Close()
defer trS.Close()
trC.writePacket([]byte{msgRequestSuccess, 0, 0})
errMsg := &disconnectMsg{
Reason: 42,
Message: "such is life",
}
trC.writePacket(Marshal(errMsg))
trC.writePacket([]byte{msgRequestSuccess, 0, 0})
packet, err := trS.readPacket()
if err != nil {
t.Fatalf("readPacket 1: %v", err)
}
if packet[0] != msgRequestSuccess {
t.Errorf("got packet %v, want packet type %d", packet, msgRequestSuccess)
}
_, err = trS.readPacket()
if err == nil {
t.Errorf("readPacket 2 succeeded")
} else if !reflect.DeepEqual(err, errMsg) {
t.Errorf("got error %#v, want %#v", err, errMsg)
}
_, err = trS.readPacket()
if err == nil {
t.Errorf("readPacket 3 succeeded")
}
}
func TestHandshakeRekeyDefault(t *testing.T) {
clientConf := &ClientConfig{
Config: Config{
Ciphers: []string{"aes128-ctr"},
},
HostKeyCallback: InsecureIgnoreHostKey(),
}
trC, trS, err := handshakePair(clientConf, "addr", false)
if err != nil {
t.Fatalf("handshakePair: %v", err)
}
defer trC.Close()
defer trS.Close()
trC.writePacket([]byte{msgRequestSuccess, 0, 0})
trC.Close()
rgb := (1024 + trC.readBytesLeft) >> 30
wgb := (1024 + trC.writeBytesLeft) >> 30
if rgb != 64 {
t.Errorf("got rekey after %dG read, want 64G", rgb)
}
if wgb != 64 {
t.Errorf("got rekey after %dG write, want 64G", wgb)
}
}