Ejemplo n.º 1
0
func (k KnownHosts) HostKeyCallback(hostname string, remote net.Addr, key ssh.PublicKey) error {
	var addr *net.TCPAddr
	if v, ok := remote.(*net.TCPAddr); ok {
		addr = v
	} else {
		return UnsupportedAddrType
	}
	keyBytes := key.Marshal()
	var matched []*Host
	for _, l := range k {
		if l.CertAuthority {
			continue
		}
		if key.Type() != l.PublicKey.Type() {
			continue
		}
		lKeyBytes := l.PublicKey.Marshal()
		for _, h := range l.Hosts {
			if h.Match(hostname, addr) {
				if !bytes.Equal(keyBytes, lKeyBytes) {
					return HostKeyMismatchError
				}
				if l.Revoked {
					return HostRevokedError
				}
				matched = append(matched, h)
			}
		}
	}
	if len(matched) == 0 {
		return HostNotFoundError
	}
	return nil
}
Ejemplo n.º 2
0
// compareKeys compares to key files and returns true of they match.
func compareKeys(a, b ssh.PublicKey) bool {
	if a.Type() != b.Type() {
		return false
	}
	// The best way to compare just the key seems to be to marshal both and
	// then compare the output byte sequence.
	return subtle.ConstantTimeCompare(a.Marshal(), b.Marshal()) == 1
}
Ejemplo n.º 3
0
func (k *storedHostKey) Check(addr string, remote net.Addr, key ssh.PublicKey) error {
	k.checkCount++
	algo := key.Type()

	if k.keys == nil || bytes.Compare(key.Marshal(), k.keys[algo]) != 0 {
		return fmt.Errorf("host key mismatch. Got %q, want %q", key, k.keys[algo])
	}
	return nil
}
Ejemplo n.º 4
0
/* logPubKey logs a public key attempt */
func logPubKey(
	conn ssh.ConnMetadata,
	key ssh.PublicKey,
) (*ssh.Permissions, error) {
	log.Printf(
		"%v Key(%v):%02X",
		ci(conn),
		key.Type(),
		md5.Sum(key.Marshal()),
	)
	return nil, fmt.Errorf("invalid key")
}
Ejemplo n.º 5
0
func testAgentInterface(t *testing.T, agent Agent, key interface{}, cert *ssh.Certificate, lifetimeSecs uint32) {
	signer, err := ssh.NewSignerFromKey(key)
	if err != nil {
		t.Fatalf("NewSignerFromKey(%T): %v", key, err)
	}
	// The agent should start up empty.
	if keys, err := agent.List(); err != nil {
		t.Fatalf("RequestIdentities: %v", err)
	} else if len(keys) > 0 {
		t.Fatalf("got %d keys, want 0: %v", len(keys), keys)
	}

	// Attempt to insert the key, with certificate if specified.
	var pubKey ssh.PublicKey
	if cert != nil {
		err = agent.Add(AddedKey{
			PrivateKey:   key,
			Certificate:  cert,
			Comment:      "comment",
			LifetimeSecs: lifetimeSecs,
		})
		pubKey = cert
	} else {
		err = agent.Add(AddedKey{PrivateKey: key, Comment: "comment", LifetimeSecs: lifetimeSecs})
		pubKey = signer.PublicKey()
	}
	if err != nil {
		t.Fatalf("insert(%T): %v", key, err)
	}

	// Did the key get inserted successfully?
	if keys, err := agent.List(); err != nil {
		t.Fatalf("List: %v", err)
	} else if len(keys) != 1 {
		t.Fatalf("got %v, want 1 key", keys)
	} else if keys[0].Comment != "comment" {
		t.Fatalf("key comment: got %v, want %v", keys[0].Comment, "comment")
	} else if !bytes.Equal(keys[0].Blob, pubKey.Marshal()) {
		t.Fatalf("key mismatch")
	}

	// Can the agent make a valid signature?
	data := []byte("hello")
	sig, err := agent.Sign(pubKey, data)
	if err != nil {
		t.Fatalf("Sign(%s): %v", pubKey.Type(), err)
	}

	if err := pubKey.Verify(data, sig); err != nil {
		t.Fatalf("Verify(%s): %v", pubKey.Type(), err)
	}
}
Ejemplo n.º 6
0
func sshToCrypto(pk ssh.PublicKey) crypto.PublicKey {
	// Don't judge me, judge the ssh.PublicKey interface. And me. A bit.
	switch pk.Type() {
	case ssh.KeyAlgoRSA:
		return (*rsa.PublicKey)(unsafe.Pointer(reflect.ValueOf(pk).Elem().UnsafeAddr()))
	case ssh.KeyAlgoDSA:
		return (*dsa.PublicKey)(unsafe.Pointer(reflect.ValueOf(pk).Elem().UnsafeAddr()))
	case ssh.KeyAlgoECDSA256, ssh.KeyAlgoECDSA384, ssh.KeyAlgoECDSA521:
		return (*ecdsa.PublicKey)(unsafe.Pointer(reflect.ValueOf(pk).Elem().UnsafeAddr()))
	default:
		return nil
	}
}
Ejemplo n.º 7
0
// authKey records any incoming request trying to auth with an ssh key
func authKey(conn ssh.ConnMetadata, key ssh.PublicKey) (*ssh.Permissions, error) {
	h := sha256.New()
	h.Write(key.Marshal())
	sum := h.Sum(nil)

	log.Printf("sshkey: %s %s %s %s\n",
		conn.RemoteAddr().String(),
		conn.User(),
		key.Type(),
		base64.StdEncoding.EncodeToString(sum))

	return nil, errAuthenticationFailed
}
Ejemplo n.º 8
0
// Check is called during the handshake to check the server's public key for
// unexpected changes. The key argument is in SSH wire format. It can be parsed
// using ssh.ParsePublicKey. The address before DNS resolution is passed in the
// addr argument, so the key can also be checked against the hostname.
// It returns any error encountered while checking the public key. A nil return
// value indicates that the key was either successfully verified (against an
// existing known_hosts entry), or accepted by the user as a new key.
func (kc *HostKeyChecker) Check(addr string, remote net.Addr, key gossh.PublicKey) error {
	remoteAddr, err := kc.addrToHostPort(remote.String())
	if err != nil {
		return err
	}

	algoStr := algoString(key.Type())
	keyFingerprintStr := md5String(md5.Sum(key.Marshal()))

	hostKeys, err := kc.m.GetHostKeys()
	_, ok := err.(*os.PathError)
	if err != nil && !ok {
		log.Errorf("Failed to read known_hosts file %v: %v", kc.m.String(), err)
	}

	mismatched := false
	for pattern, keys := range hostKeys {
		if !matchHost(remoteAddr, pattern) {
			continue
		}
		for _, hostKey := range keys {
			// Any matching key is considered a success, irrespective of previous failures
			if hostKey.Type() == key.Type() && bytes.Compare(hostKey.Marshal(), key.Marshal()) == 0 {
				return nil
			}
			// TODO(jonboulle): could be super friendly like the OpenSSH client
			// and note exactly which key failed (file + line number)
			mismatched = true
		}
	}

	if mismatched {
		fmt.Fprintf(os.Stderr, warningRemoteHostChanged, algoStr, keyFingerprintStr, kc.m.String())
		return ErrUnmatchKey
	}

	// If we get this far, we haven't matched on any of the hostname patterns,
	// so it's considered a new key. Prompt the user to trust it.
	if !kc.trustHost(remoteAddr, algoStr, keyFingerprintStr) {
		fmt.Fprintln(os.Stderr, "Host key verification failed.")
		return ErrUntrustHost
	}

	if err := kc.m.PutHostKey(remoteAddr, key); err != nil {
		fmt.Fprintf(os.Stderr, "Failed to add the host to the list of known hosts (%v).\n", kc.m)
		return nil
	}

	fmt.Fprintf(os.Stderr, "Warning: Permanently added '%v' (%v) to the list of known hosts.\n", remoteAddr, algoStr)
	return nil
}
Ejemplo n.º 9
0
func (inst *instance) hostKeyCallback(hostname string, remote net.Addr, key ssh.PublicKey) error {
	oldPublicKey, err := hex.DecodeString(inst.conn.Options.SSHPublicKey)
	if err != nil {
		return errors.New("XML is corrupt: " + err.Error())
	}
	newPublicKey := key.Marshal()
	//TODO correctly marshal/unmarshal into xml

	newPublicMD5 := md5.Sum(newPublicKey)
	newPublicString := hex.EncodeToString(newPublicMD5[:])

	if len(oldPublicKey) == 0 {
		color.Yellowln("Registering new SSH Public Key", key.Type(),
			newPublicString)
		inst.conn.Options.SSHPublicKey = hex.EncodeToString(newPublicKey)
		inst.changed = true
		return nil
	}

	oldPublicMD5 := md5.Sum(oldPublicKey)
	oldPublicString := hex.EncodeToString(oldPublicMD5[:])

	same := subtle.ConstantTimeCompare(newPublicKey, oldPublicKey)
	if same == 1 {
		return nil
	}
	color.Redln("-----POSSIBLE ATTACK-----\nSSH key changed! expected (md5):",
		oldPublicString,
		"got:", newPublicString, "type:", key.Type())
	inst.terminal.Stderr().Write([]byte("Accept change [Ny]? "))

	buf := make([]byte, 128)
	n, err := inst.terminal.Stdin().Read(buf)
	if err != nil {
		color.Yellowln("Error reading answer:", err)
		return err
	}
	inst.terminal.Stderr().Write([]byte{'\n'})

	text := strings.ToLower(string(buf[:n]))
	if text == "y" || text == "yes" {
		inst.conn.Options.SSHPublicKey = hex.EncodeToString(newPublicKey)
		inst.changed = true
		color.Yellowln("Saving new public key to connections.xml on exit.")
		return nil
	}
	return errors.New("Public key not accepted")
}
Ejemplo n.º 10
0
func keyAuth(conn ssh.ConnMetadata, key ssh.PublicKey) (*ssh.Permissions, error) {

	log.Println(conn.RemoteAddr(), "authenticate with", key.Type(), "for user", conn.User())
	log.Println(base64.StdEncoding.EncodeToString(key.Marshal()))

	if isValidToken(conn.User()) {
		authRequestMap.Lock()
		authRequestMap.matches[conn.User()] = key.Type() + " " + base64.StdEncoding.EncodeToString(key.Marshal())
		authRequestMap.timestamps[conn.User()] = time.Now()
		authRequestMap.Unlock()
		return nil, nil
	}

	//Causes "Permission denied (publickey)." for openssh. How can this bubble up to the user?
	return nil, errors.New("Invalid token/username.")
}
Ejemplo n.º 11
0
func (s *Server) auth(conn ssh.ConnMetadata, key ssh.PublicKey) (*ssh.Permissions, error) {
	k := key.Marshal()
	t := key.Type()
	perm := &ssh.Permissions{
		Extensions: map[string]string{
			"pubKey":     string(k),
			"pubKeyType": t,
		},
	}

	_, err := s.Auther(conn, key)
	if err == nil {
		return perm, nil
	}

	return nil, err
}
Ejemplo n.º 12
0
func keyAuthCallback(conn ssh.ConnMetadata, key ssh.PublicKey) (*ssh.Permissions, error) {
	guid := uuid.NewV4()
	ip, remotePort := parseIpPortFrom(conn)
	login := SshLogin{RemoteAddr: ip,
		RemotePort: remotePort,
		Username:   conn.User(),
		Guid:       guid.String(),
		Version:    string(conn.ClientVersion()),
		PublicKey:  key.Marshal(),
		KeyType:    string(key.Type()),
		LoginType:  "key",
	}
	go login.Save()
	//log.Println("Fail to authenticate", conn, ":", err)
	//return nil, errors.New("invalid authentication")
	return &ssh.Permissions{Extensions: map[string]string{"guid": guid.String()}}, nil
}
Ejemplo n.º 13
0
// authKey records any incoming request trying to auth with an ssh key
func authKey(conn ssh.ConnMetadata, key ssh.PublicKey) (*ssh.Permissions, error) {

	r := &AuthEvent{
		Time:     fmt.Sprintf("%d", time.Now().Unix()),
		AuthType: "sshKey",
		SrcIP:    strings.Split(conn.RemoteAddr().String(), ":")[0],
		DestIP:   extIP,
		User:     conn.User(),
		TypeData: fmt.Sprintf("ssh-key-type: %s client-version: %s", key.Type(), strconv.QuoteToASCII(string(conn.ClientVersion()))),
	}

	h := sha256.New()
	h.Write(key.Marshal())
	r.Credentials = base64.StdEncoding.EncodeToString(h.Sum(nil))

	addToBatch(r)

	return nil, errAuthenticationFailed
}
Ejemplo n.º 14
0
func (config BeaconConfig) checkHostKey(hostname string, remote net.Addr, key ssh.PublicKey) error {
	hostPublicKeyBytes, err := ioutil.ReadFile(string(config.PublicKey))
	if err != nil {
		return fmt.Errorf("failed to read host public key: %s", err)
	}

	hostPublicKey, _, _, _, err := ssh.ParseAuthorizedKey(hostPublicKeyBytes)
	if err != nil {
		return fmt.Errorf("failed to parse host public key: %s", err)
	}

	// note: hostname/addr are not verified; they may be behind a load balancer
	// so the definition gets a bit fuzzy

	if hostPublicKey.Type() != key.Type() || !bytes.Equal(hostPublicKey.Marshal(), key.Marshal()) {
		return errors.New("remote host public key mismatch")
	}

	return nil
}
Ejemplo n.º 15
0
func keyAuth(conn ssh.ConnMetadata, key ssh.PublicKey) (*ssh.Permissions, error) {
	log.Println(conn.RemoteAddr(), "authenticate with", key.Type())
	return nil, nil
}
Ejemplo n.º 16
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func (k *storedHostKey) Add(key ssh.PublicKey) {
	if k.keys == nil {
		k.keys = map[string][]byte{}
	}
	k.keys[key.Type()] = key.Marshal()
}
Ejemplo n.º 17
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func keyAuth(conn ssh.ConnMetadata, key ssh.PublicKey) (*ssh.Permissions, error) {
	log.Printf("(keyAuth) >>  New client conn from '%s' authenticating with '%s'\n", conn.RemoteAddr(), key.Type())
	// Check if the user is allowed to connect at all (meaning: the must be a subdirectory in the 'data' dir
	// matching the provided SSH username).
	authorizedPubKey, err := getPubKeyForUser(conn.User())
	if err != nil {
		return nil, fmt.Errorf("(keyAuth) >>  No pub key for user '%s' found / user not allowed to connect.", conn.User())

	}

	fpProvidedPubKey, err := pubKeyFingerprint(key)
	if err != nil {
		log.Printf("(keyAuth) >>  Error: Unable to create fingerprint for provided PubKey: %s\n", err.Error())
	}
	log.Printf("(keyAuth) >>  Fingerprint of provided PubKey  : %s\n", fpProvidedPubKey)
	fpAuthorizedPubKey, err := pubKeyFingerprint(authorizedPubKey)
	if err != nil {
		log.Printf("(keyAuth) >>  Error: Unable to create fingerprint for authorized PubKey: %s\n", err.Error())
	}
	log.Printf("(keyAuth) >>  Fingerprint of authorized PubKey: %s\n", fpAuthorizedPubKey)

	// Check if username and Public Key combination is allowed to establish a connection.
	if theseTwoPublicKeysAreEqual(key, authorizedPubKey) {
		log.Printf("(keyAuth) >>  Correct username '%s' and public key provided.", conn.User())
		// Signaling success / authentication passed.
		return nil, nil
	}
	log.Printf("(keyAuth) >>  Wrong username '%s' and/or public key provided.", conn.User())
	return nil, fmt.Errorf("Wrong username and/or public key.")
}
Ejemplo n.º 18
0
func (c *SSHCluster) hostKeyCallback(hostname string, remote net.Addr, key ssh.PublicKey) error {
	if c.knownHosts == nil {
		if err := c.parseKnownHosts(); err != nil {
			return err
		}
	}
	err := c.knownHosts.HostKeyCallback(hostname, remote, key)
	if err == knownhosts.HostNotFoundError {
		fingerprint := c.fingerprintSSHKey(key)
		hostnameFormatted := hostname
		remoteAddr := remote.String()
		if remoteAddr != hostname {
			hostnameFormatted = fmt.Sprintf("%s (%s)", hostname, remoteAddr)
		}
		if c.base.YesNoPrompt(fmt.Sprintf("The authenticity of host '%s' can't be established.\n%s key fingerprint is %s.\nAre you sure you want to continue connecting?", hostnameFormatted, key.Type(), fingerprint)) {
			c.base.SendLog(fmt.Sprintf("Trusting '%s' with key fingerprint %s", hostnameFormatted, fingerprint))
			file, err := os.OpenFile(c.knownHostsPath(), os.O_CREATE|os.O_WRONLY|os.O_APPEND, os.FileMode(0644))
			if err != nil {
				c.base.SendLog(fmt.Sprintf("WARNING: Can't write to %s: %s", c.knownHostsPath(), err))
			} else {
				defer file.Close()
			}
			c.knownHosts.AppendHost(hostname, key, file)
			return nil
		}
	}
	return err
}