update package dependencies (#5463)

Signed-off-by: fsl <1171313930@qq.com>

Signed-off-by: fsl <1171313930@qq.com>
This commit is contained in:
fsl
2023-01-13 15:33:36 +08:00
committed by GitHub
parent 30d10cac53
commit efac3bde8f
471 changed files with 101081 additions and 36331 deletions

View File

@@ -8,7 +8,8 @@
// ssh-agent process using the sample server.
//
// References:
// [PROTOCOL.agent]: https://tools.ietf.org/html/draft-miller-ssh-agent-00
//
// [PROTOCOL.agent]: https://tools.ietf.org/html/draft-miller-ssh-agent-00
package agent // import "golang.org/x/crypto/ssh/agent"
import (
@@ -25,7 +26,6 @@ import (
"math/big"
"sync"
"crypto"
"golang.org/x/crypto/ed25519"
"golang.org/x/crypto/ssh"
)
@@ -93,7 +93,7 @@ type ExtendedAgent interface {
type ConstraintExtension struct {
// ExtensionName consist of a UTF-8 string suffixed by the
// implementation domain following the naming scheme defined
// in Section 4.2 of [RFC4251], e.g. "foo@example.com".
// in Section 4.2 of RFC 4251, e.g. "foo@example.com".
ExtensionName string
// ExtensionDetails contains the actual content of the extended
// constraint.
@@ -226,7 +226,9 @@ var ErrExtensionUnsupported = errors.New("agent: extension unsupported")
type extensionAgentMsg struct {
ExtensionType string `sshtype:"27"`
Contents []byte
// NOTE: this matches OpenSSH's PROTOCOL.agent, not the IETF draft [PROTOCOL.agent],
// so that it matches what OpenSSH actually implements in the wild.
Contents []byte `ssh:"rest"`
}
// Key represents a protocol 2 public key as defined in
@@ -729,7 +731,7 @@ func (c *client) insertCert(s interface{}, cert *ssh.Certificate, comment string
if err != nil {
return err
}
if bytes.Compare(cert.Key.Marshal(), signer.PublicKey().Marshal()) != 0 {
if !bytes.Equal(cert.Key.Marshal(), signer.PublicKey().Marshal()) {
return errors.New("agent: signer and cert have different public key")
}
@@ -771,19 +773,53 @@ func (s *agentKeyringSigner) Sign(rand io.Reader, data []byte) (*ssh.Signature,
return s.agent.Sign(s.pub, data)
}
func (s *agentKeyringSigner) SignWithOpts(rand io.Reader, data []byte, opts crypto.SignerOpts) (*ssh.Signature, error) {
var flags SignatureFlags
if opts != nil {
switch opts.HashFunc() {
case crypto.SHA256:
flags = SignatureFlagRsaSha256
case crypto.SHA512:
flags = SignatureFlagRsaSha512
}
func (s *agentKeyringSigner) SignWithAlgorithm(rand io.Reader, data []byte, algorithm string) (*ssh.Signature, error) {
if algorithm == "" || algorithm == underlyingAlgo(s.pub.Type()) {
return s.Sign(rand, data)
}
var flags SignatureFlags
switch algorithm {
case ssh.KeyAlgoRSASHA256:
flags = SignatureFlagRsaSha256
case ssh.KeyAlgoRSASHA512:
flags = SignatureFlagRsaSha512
default:
return nil, fmt.Errorf("agent: unsupported algorithm %q", algorithm)
}
return s.agent.SignWithFlags(s.pub, data, flags)
}
var _ ssh.AlgorithmSigner = &agentKeyringSigner{}
// certKeyAlgoNames is a mapping from known certificate algorithm names to the
// corresponding public key signature algorithm.
//
// This map must be kept in sync with the one in certs.go.
var certKeyAlgoNames = map[string]string{
ssh.CertAlgoRSAv01: ssh.KeyAlgoRSA,
ssh.CertAlgoRSASHA256v01: ssh.KeyAlgoRSASHA256,
ssh.CertAlgoRSASHA512v01: ssh.KeyAlgoRSASHA512,
ssh.CertAlgoDSAv01: ssh.KeyAlgoDSA,
ssh.CertAlgoECDSA256v01: ssh.KeyAlgoECDSA256,
ssh.CertAlgoECDSA384v01: ssh.KeyAlgoECDSA384,
ssh.CertAlgoECDSA521v01: ssh.KeyAlgoECDSA521,
ssh.CertAlgoSKECDSA256v01: ssh.KeyAlgoSKECDSA256,
ssh.CertAlgoED25519v01: ssh.KeyAlgoED25519,
ssh.CertAlgoSKED25519v01: ssh.KeyAlgoSKED25519,
}
// underlyingAlgo returns the signature algorithm associated with algo (which is
// an advertised or negotiated public key or host key algorithm). These are
// usually the same, except for certificate algorithms.
func underlyingAlgo(algo string) string {
if a, ok := certKeyAlgoNames[algo]; ok {
return a
}
return algo
}
// Calls an extension method. It is up to the agent implementation as to whether or not
// any particular extension is supported and may always return an error. Because the
// type of the response is up to the implementation, this returns the bytes of the

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@@ -113,7 +113,7 @@ func (r *keyring) Unlock(passphrase []byte) error {
// expireKeysLocked removes expired keys from the keyring. If a key was added
// with a lifetimesecs contraint and seconds >= lifetimesecs seconds have
// ellapsed, it is removed. The caller *must* be holding the keyring mutex.
// elapsed, it is removed. The caller *must* be holding the keyring mutex.
func (r *keyring) expireKeysLocked() {
for _, k := range r.keys {
if k.expire != nil && time.Now().After(*k.expire) {
@@ -205,9 +205,9 @@ func (r *keyring) SignWithFlags(key ssh.PublicKey, data []byte, flags SignatureF
var algorithm string
switch flags {
case SignatureFlagRsaSha256:
algorithm = ssh.SigAlgoRSASHA2256
algorithm = ssh.KeyAlgoRSASHA256
case SignatureFlagRsaSha512:
algorithm = ssh.SigAlgoRSASHA2512
algorithm = ssh.KeyAlgoRSASHA512
default:
return nil, fmt.Errorf("agent: unsupported signature flags: %d", flags)
}

View File

@@ -14,8 +14,10 @@ import (
"time"
)
// These constants from [PROTOCOL.certkeys] represent the algorithm names
// for certificate types supported by this package.
// Certificate algorithm names from [PROTOCOL.certkeys]. These values can appear
// in Certificate.Type, PublicKey.Type, and ClientConfig.HostKeyAlgorithms.
// Unlike key algorithm names, these are not passed to AlgorithmSigner and don't
// appear in the Signature.Format field.
const (
CertAlgoRSAv01 = "ssh-rsa-cert-v01@openssh.com"
CertAlgoDSAv01 = "ssh-dss-cert-v01@openssh.com"
@@ -25,6 +27,21 @@ const (
CertAlgoSKECDSA256v01 = "sk-ecdsa-sha2-nistp256-cert-v01@openssh.com"
CertAlgoED25519v01 = "ssh-ed25519-cert-v01@openssh.com"
CertAlgoSKED25519v01 = "sk-ssh-ed25519-cert-v01@openssh.com"
// CertAlgoRSASHA256v01 and CertAlgoRSASHA512v01 can't appear as a
// Certificate.Type (or PublicKey.Type), but only in
// ClientConfig.HostKeyAlgorithms.
CertAlgoRSASHA256v01 = "rsa-sha2-256-cert-v01@openssh.com"
CertAlgoRSASHA512v01 = "rsa-sha2-512-cert-v01@openssh.com"
)
const (
// Deprecated: use CertAlgoRSAv01.
CertSigAlgoRSAv01 = CertAlgoRSAv01
// Deprecated: use CertAlgoRSASHA256v01.
CertSigAlgoRSASHA2256v01 = CertAlgoRSASHA256v01
// Deprecated: use CertAlgoRSASHA512v01.
CertSigAlgoRSASHA2512v01 = CertAlgoRSASHA512v01
)
// Certificate types distinguish between host and user
@@ -234,7 +251,7 @@ type algorithmOpenSSHCertSigner struct {
// private key is held by signer. It returns an error if the public key in cert
// doesn't match the key used by signer.
func NewCertSigner(cert *Certificate, signer Signer) (Signer, error) {
if bytes.Compare(cert.Key.Marshal(), signer.PublicKey().Marshal()) != 0 {
if !bytes.Equal(cert.Key.Marshal(), signer.PublicKey().Marshal()) {
return nil, errors.New("ssh: signer and cert have different public key")
}
@@ -423,6 +440,16 @@ func (c *Certificate) SignCert(rand io.Reader, authority Signer) error {
}
c.SignatureKey = authority.PublicKey()
// Default to KeyAlgoRSASHA512 for ssh-rsa signers.
if v, ok := authority.(AlgorithmSigner); ok && v.PublicKey().Type() == KeyAlgoRSA {
sig, err := v.SignWithAlgorithm(rand, c.bytesForSigning(), KeyAlgoRSASHA512)
if err != nil {
return err
}
c.Signature = sig
return nil
}
sig, err := authority.Sign(rand, c.bytesForSigning())
if err != nil {
return err
@@ -431,26 +458,42 @@ func (c *Certificate) SignCert(rand io.Reader, authority Signer) error {
return nil
}
var certAlgoNames = map[string]string{
KeyAlgoRSA: CertAlgoRSAv01,
KeyAlgoDSA: CertAlgoDSAv01,
KeyAlgoECDSA256: CertAlgoECDSA256v01,
KeyAlgoECDSA384: CertAlgoECDSA384v01,
KeyAlgoECDSA521: CertAlgoECDSA521v01,
KeyAlgoSKECDSA256: CertAlgoSKECDSA256v01,
KeyAlgoED25519: CertAlgoED25519v01,
KeyAlgoSKED25519: CertAlgoSKED25519v01,
// certKeyAlgoNames is a mapping from known certificate algorithm names to the
// corresponding public key signature algorithm.
//
// This map must be kept in sync with the one in agent/client.go.
var certKeyAlgoNames = map[string]string{
CertAlgoRSAv01: KeyAlgoRSA,
CertAlgoRSASHA256v01: KeyAlgoRSASHA256,
CertAlgoRSASHA512v01: KeyAlgoRSASHA512,
CertAlgoDSAv01: KeyAlgoDSA,
CertAlgoECDSA256v01: KeyAlgoECDSA256,
CertAlgoECDSA384v01: KeyAlgoECDSA384,
CertAlgoECDSA521v01: KeyAlgoECDSA521,
CertAlgoSKECDSA256v01: KeyAlgoSKECDSA256,
CertAlgoED25519v01: KeyAlgoED25519,
CertAlgoSKED25519v01: KeyAlgoSKED25519,
}
// certToPrivAlgo returns the underlying algorithm for a certificate algorithm.
// Panics if a non-certificate algorithm is passed.
func certToPrivAlgo(algo string) string {
for privAlgo, pubAlgo := range certAlgoNames {
if pubAlgo == algo {
return privAlgo
// underlyingAlgo returns the signature algorithm associated with algo (which is
// an advertised or negotiated public key or host key algorithm). These are
// usually the same, except for certificate algorithms.
func underlyingAlgo(algo string) string {
if a, ok := certKeyAlgoNames[algo]; ok {
return a
}
return algo
}
// certificateAlgo returns the certificate algorithms that uses the provided
// underlying signature algorithm.
func certificateAlgo(algo string) (certAlgo string, ok bool) {
for certName, algoName := range certKeyAlgoNames {
if algoName == algo {
return certName, true
}
}
panic("unknown cert algorithm")
return "", false
}
func (cert *Certificate) bytesForSigning() []byte {
@@ -494,13 +537,13 @@ func (c *Certificate) Marshal() []byte {
return result
}
// Type returns the key name. It is part of the PublicKey interface.
// Type returns the certificate algorithm name. It is part of the PublicKey interface.
func (c *Certificate) Type() string {
algo, ok := certAlgoNames[c.Key.Type()]
certName, ok := certificateAlgo(c.Key.Type())
if !ok {
panic("unknown cert key type " + c.Key.Type())
panic("unknown certificate type for key type " + c.Key.Type())
}
return algo
return certName
}
// Verify verifies a signature against the certificate's public

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@@ -15,10 +15,9 @@ import (
"fmt"
"hash"
"io"
"io/ioutil"
"golang.org/x/crypto/chacha20"
"golang.org/x/crypto/poly1305"
"golang.org/x/crypto/internal/poly1305"
)
const (
@@ -97,13 +96,13 @@ func streamCipherMode(skip int, createFunc func(key, iv []byte) (cipher.Stream,
// are not supported and will not be negotiated, even if explicitly requested in
// ClientConfig.Crypto.Ciphers.
var cipherModes = map[string]*cipherMode{
// Ciphers from RFC4344, which introduced many CTR-based ciphers. Algorithms
// Ciphers from RFC 4344, which introduced many CTR-based ciphers. Algorithms
// are defined in the order specified in the RFC.
"aes128-ctr": {16, aes.BlockSize, streamCipherMode(0, newAESCTR)},
"aes192-ctr": {24, aes.BlockSize, streamCipherMode(0, newAESCTR)},
"aes256-ctr": {32, aes.BlockSize, streamCipherMode(0, newAESCTR)},
// Ciphers from RFC4345, which introduces security-improved arcfour ciphers.
// Ciphers from RFC 4345, which introduces security-improved arcfour ciphers.
// They are defined in the order specified in the RFC.
"arcfour128": {16, 0, streamCipherMode(1536, newRC4)},
"arcfour256": {32, 0, streamCipherMode(1536, newRC4)},
@@ -111,7 +110,7 @@ var cipherModes = map[string]*cipherMode{
// Cipher defined in RFC 4253, which describes SSH Transport Layer Protocol.
// Note that this cipher is not safe, as stated in RFC 4253: "Arcfour (and
// RC4) has problems with weak keys, and should be used with caution."
// RFC4345 introduces improved versions of Arcfour.
// RFC 4345 introduces improved versions of Arcfour.
"arcfour": {16, 0, streamCipherMode(0, newRC4)},
// AEAD ciphers
@@ -394,6 +393,10 @@ func (c *gcmCipher) readCipherPacket(seqNum uint32, r io.Reader) ([]byte, error)
}
c.incIV()
if len(plain) == 0 {
return nil, errors.New("ssh: empty packet")
}
padding := plain[0]
if padding < 4 {
// padding is a byte, so it automatically satisfies
@@ -493,7 +496,7 @@ func (c *cbcCipher) readCipherPacket(seqNum uint32, r io.Reader) ([]byte, error)
// data, to make distinguishing between
// failing MAC and failing length check more
// difficult.
io.CopyN(ioutil.Discard, r, int64(c.oracleCamouflage))
io.CopyN(io.Discard, r, int64(c.oracleCamouflage))
}
}
return p, err
@@ -636,9 +639,9 @@ const chacha20Poly1305ID = "chacha20-poly1305@openssh.com"
// chacha20Poly1305Cipher implements the chacha20-poly1305@openssh.com
// AEAD, which is described here:
//
// https://tools.ietf.org/html/draft-josefsson-ssh-chacha20-poly1305-openssh-00
// https://tools.ietf.org/html/draft-josefsson-ssh-chacha20-poly1305-openssh-00
//
// the methods here also implement padding, which RFC4253 Section 6
// the methods here also implement padding, which RFC 4253 Section 6
// also requires of stream ciphers.
type chacha20Poly1305Cipher struct {
lengthKey [32]byte
@@ -710,6 +713,10 @@ func (c *chacha20Poly1305Cipher) readCipherPacket(seqNum uint32, r io.Reader) ([
plain := c.buf[4:contentEnd]
s.XORKeyStream(plain, plain)
if len(plain) == 0 {
return nil, errors.New("ssh: empty packet")
}
padding := plain[0]
if padding < 4 {
// padding is a byte, so it automatically satisfies

View File

@@ -113,14 +113,18 @@ func (c *connection) clientHandshake(dialAddress string, config *ClientConfig) e
return c.clientAuthenticate(config)
}
// verifyHostKeySignature verifies the host key obtained in the key
// exchange.
func verifyHostKeySignature(hostKey PublicKey, result *kexResult) error {
// verifyHostKeySignature verifies the host key obtained in the key exchange.
// algo is the negotiated algorithm, and may be a certificate type.
func verifyHostKeySignature(hostKey PublicKey, algo string, result *kexResult) error {
sig, rest, ok := parseSignatureBody(result.Signature)
if len(rest) > 0 || !ok {
return errors.New("ssh: signature parse error")
}
if a := underlyingAlgo(algo); sig.Format != a {
return fmt.Errorf("ssh: invalid signature algorithm %q, expected %q", sig.Format, a)
}
return hostKey.Verify(result.H, sig)
}
@@ -224,11 +228,11 @@ type ClientConfig struct {
// be used for the connection. If empty, a reasonable default is used.
ClientVersion string
// HostKeyAlgorithms lists the key types that the client will
// accept from the server as host key, in order of
// HostKeyAlgorithms lists the public key algorithms that the client will
// accept from the server for host key authentication, in order of
// preference. If empty, a reasonable default is used. Any
// string returned from PublicKey.Type method may be used, or
// any of the CertAlgoXxxx and KeyAlgoXxxx constants.
// string returned from a PublicKey.Type method may be used, or
// any of the CertAlgo and KeyAlgo constants.
HostKeyAlgorithms []string
// Timeout is the maximum amount of time for the TCP connection to establish.

View File

@@ -9,6 +9,7 @@ import (
"errors"
"fmt"
"io"
"strings"
)
type authResult int
@@ -29,6 +30,33 @@ func (c *connection) clientAuthenticate(config *ClientConfig) error {
if err != nil {
return err
}
// The server may choose to send a SSH_MSG_EXT_INFO at this point (if we
// advertised willingness to receive one, which we always do) or not. See
// RFC 8308, Section 2.4.
extensions := make(map[string][]byte)
if len(packet) > 0 && packet[0] == msgExtInfo {
var extInfo extInfoMsg
if err := Unmarshal(packet, &extInfo); err != nil {
return err
}
payload := extInfo.Payload
for i := uint32(0); i < extInfo.NumExtensions; i++ {
name, rest, ok := parseString(payload)
if !ok {
return parseError(msgExtInfo)
}
value, rest, ok := parseString(rest)
if !ok {
return parseError(msgExtInfo)
}
extensions[string(name)] = value
payload = rest
}
packet, err = c.transport.readPacket()
if err != nil {
return err
}
}
var serviceAccept serviceAcceptMsg
if err := Unmarshal(packet, &serviceAccept); err != nil {
return err
@@ -41,7 +69,7 @@ func (c *connection) clientAuthenticate(config *ClientConfig) error {
sessionID := c.transport.getSessionID()
for auth := AuthMethod(new(noneAuth)); auth != nil; {
ok, methods, err := auth.auth(sessionID, config.User, c.transport, config.Rand)
ok, methods, err := auth.auth(sessionID, config.User, c.transport, config.Rand, extensions)
if err != nil {
return err
}
@@ -93,7 +121,7 @@ type AuthMethod interface {
// If authentication is not successful, a []string of alternative
// method names is returned. If the slice is nil, it will be ignored
// and the previous set of possible methods will be reused.
auth(session []byte, user string, p packetConn, rand io.Reader) (authResult, []string, error)
auth(session []byte, user string, p packetConn, rand io.Reader, extensions map[string][]byte) (authResult, []string, error)
// method returns the RFC 4252 method name.
method() string
@@ -102,7 +130,7 @@ type AuthMethod interface {
// "none" authentication, RFC 4252 section 5.2.
type noneAuth int
func (n *noneAuth) auth(session []byte, user string, c packetConn, rand io.Reader) (authResult, []string, error) {
func (n *noneAuth) auth(session []byte, user string, c packetConn, rand io.Reader, _ map[string][]byte) (authResult, []string, error) {
if err := c.writePacket(Marshal(&userAuthRequestMsg{
User: user,
Service: serviceSSH,
@@ -122,7 +150,7 @@ func (n *noneAuth) method() string {
// a function call, e.g. by prompting the user.
type passwordCallback func() (password string, err error)
func (cb passwordCallback) auth(session []byte, user string, c packetConn, rand io.Reader) (authResult, []string, error) {
func (cb passwordCallback) auth(session []byte, user string, c packetConn, rand io.Reader, _ map[string][]byte) (authResult, []string, error) {
type passwordAuthMsg struct {
User string `sshtype:"50"`
Service string
@@ -189,7 +217,46 @@ func (cb publicKeyCallback) method() string {
return "publickey"
}
func (cb publicKeyCallback) auth(session []byte, user string, c packetConn, rand io.Reader) (authResult, []string, error) {
func pickSignatureAlgorithm(signer Signer, extensions map[string][]byte) (as AlgorithmSigner, algo string) {
keyFormat := signer.PublicKey().Type()
// Like in sendKexInit, if the public key implements AlgorithmSigner we
// assume it supports all algorithms, otherwise only the key format one.
as, ok := signer.(AlgorithmSigner)
if !ok {
return algorithmSignerWrapper{signer}, keyFormat
}
extPayload, ok := extensions["server-sig-algs"]
if !ok {
// If there is no "server-sig-algs" extension, fall back to the key
// format algorithm.
return as, keyFormat
}
// The server-sig-algs extension only carries underlying signature
// algorithm, but we are trying to select a protocol-level public key
// algorithm, which might be a certificate type. Extend the list of server
// supported algorithms to include the corresponding certificate algorithms.
serverAlgos := strings.Split(string(extPayload), ",")
for _, algo := range serverAlgos {
if certAlgo, ok := certificateAlgo(algo); ok {
serverAlgos = append(serverAlgos, certAlgo)
}
}
keyAlgos := algorithmsForKeyFormat(keyFormat)
algo, err := findCommon("public key signature algorithm", keyAlgos, serverAlgos)
if err != nil {
// If there is no overlap, try the key anyway with the key format
// algorithm, to support servers that fail to list all supported
// algorithms.
return as, keyFormat
}
return as, algo
}
func (cb publicKeyCallback) auth(session []byte, user string, c packetConn, rand io.Reader, extensions map[string][]byte) (authResult, []string, error) {
// Authentication is performed by sending an enquiry to test if a key is
// acceptable to the remote. If the key is acceptable, the client will
// attempt to authenticate with the valid key. If not the client will repeat
@@ -201,7 +268,10 @@ func (cb publicKeyCallback) auth(session []byte, user string, c packetConn, rand
}
var methods []string
for _, signer := range signers {
ok, err := validateKey(signer.PublicKey(), user, c)
pub := signer.PublicKey()
as, algo := pickSignatureAlgorithm(signer, extensions)
ok, err := validateKey(pub, algo, user, c)
if err != nil {
return authFailure, nil, err
}
@@ -209,13 +279,13 @@ func (cb publicKeyCallback) auth(session []byte, user string, c packetConn, rand
continue
}
pub := signer.PublicKey()
pubKey := pub.Marshal()
sign, err := signer.Sign(rand, buildDataSignedForAuth(session, userAuthRequestMsg{
data := buildDataSignedForAuth(session, userAuthRequestMsg{
User: user,
Service: serviceSSH,
Method: cb.method(),
}, []byte(pub.Type()), pubKey))
}, algo, pubKey)
sign, err := as.SignWithAlgorithm(rand, data, underlyingAlgo(algo))
if err != nil {
return authFailure, nil, err
}
@@ -229,7 +299,7 @@ func (cb publicKeyCallback) auth(session []byte, user string, c packetConn, rand
Service: serviceSSH,
Method: cb.method(),
HasSig: true,
Algoname: pub.Type(),
Algoname: algo,
PubKey: pubKey,
Sig: sig,
}
@@ -266,26 +336,25 @@ func containsMethod(methods []string, method string) bool {
}
// validateKey validates the key provided is acceptable to the server.
func validateKey(key PublicKey, user string, c packetConn) (bool, error) {
func validateKey(key PublicKey, algo string, user string, c packetConn) (bool, error) {
pubKey := key.Marshal()
msg := publickeyAuthMsg{
User: user,
Service: serviceSSH,
Method: "publickey",
HasSig: false,
Algoname: key.Type(),
Algoname: algo,
PubKey: pubKey,
}
if err := c.writePacket(Marshal(&msg)); err != nil {
return false, err
}
return confirmKeyAck(key, c)
return confirmKeyAck(key, algo, c)
}
func confirmKeyAck(key PublicKey, c packetConn) (bool, error) {
func confirmKeyAck(key PublicKey, algo string, c packetConn) (bool, error) {
pubKey := key.Marshal()
algoname := key.Type()
for {
packet, err := c.readPacket()
@@ -302,14 +371,14 @@ func confirmKeyAck(key PublicKey, c packetConn) (bool, error) {
if err := Unmarshal(packet, &msg); err != nil {
return false, err
}
if msg.Algo != algoname || !bytes.Equal(msg.PubKey, pubKey) {
if msg.Algo != algo || !bytes.Equal(msg.PubKey, pubKey) {
return false, nil
}
return true, nil
case msgUserAuthFailure:
return false, nil
default:
return false, unexpectedMessageError(msgUserAuthSuccess, packet[0])
return false, unexpectedMessageError(msgUserAuthPubKeyOk, packet[0])
}
}
}
@@ -330,6 +399,7 @@ func PublicKeysCallback(getSigners func() (signers []Signer, err error)) AuthMet
// along with a list of remaining authentication methods to try next and
// an error if an unexpected response was received.
func handleAuthResponse(c packetConn) (authResult, []string, error) {
gotMsgExtInfo := false
for {
packet, err := c.readPacket()
if err != nil {
@@ -341,6 +411,12 @@ func handleAuthResponse(c packetConn) (authResult, []string, error) {
if err := handleBannerResponse(c, packet); err != nil {
return authFailure, nil, err
}
case msgExtInfo:
// Ignore post-authentication RFC 8308 extensions, once.
if gotMsgExtInfo {
return authFailure, nil, unexpectedMessageError(msgUserAuthSuccess, packet[0])
}
gotMsgExtInfo = true
case msgUserAuthFailure:
var msg userAuthFailureMsg
if err := Unmarshal(packet, &msg); err != nil {
@@ -380,10 +456,10 @@ func handleBannerResponse(c packetConn, packet []byte) error {
// disabling echoing (e.g. for passwords), and return all the answers.
// Challenge may be called multiple times in a single session. After
// successful authentication, the server may send a challenge with no
// questions, for which the user and instruction messages should be
// questions, for which the name and instruction messages should be
// printed. RFC 4256 section 3.3 details how the UI should behave for
// both CLI and GUI environments.
type KeyboardInteractiveChallenge func(user, instruction string, questions []string, echos []bool) (answers []string, err error)
type KeyboardInteractiveChallenge func(name, instruction string, questions []string, echos []bool) (answers []string, err error)
// KeyboardInteractive returns an AuthMethod using a prompt/response
// sequence controlled by the server.
@@ -395,7 +471,7 @@ func (cb KeyboardInteractiveChallenge) method() string {
return "keyboard-interactive"
}
func (cb KeyboardInteractiveChallenge) auth(session []byte, user string, c packetConn, rand io.Reader) (authResult, []string, error) {
func (cb KeyboardInteractiveChallenge) auth(session []byte, user string, c packetConn, rand io.Reader, _ map[string][]byte) (authResult, []string, error) {
type initiateMsg struct {
User string `sshtype:"50"`
Service string
@@ -412,6 +488,7 @@ func (cb KeyboardInteractiveChallenge) auth(session []byte, user string, c packe
return authFailure, nil, err
}
gotMsgExtInfo := false
for {
packet, err := c.readPacket()
if err != nil {
@@ -425,6 +502,13 @@ func (cb KeyboardInteractiveChallenge) auth(session []byte, user string, c packe
return authFailure, nil, err
}
continue
case msgExtInfo:
// Ignore post-authentication RFC 8308 extensions, once.
if gotMsgExtInfo {
return authFailure, nil, unexpectedMessageError(msgUserAuthInfoRequest, packet[0])
}
gotMsgExtInfo = true
continue
case msgUserAuthInfoRequest:
// OK
case msgUserAuthFailure:
@@ -465,7 +549,7 @@ func (cb KeyboardInteractiveChallenge) auth(session []byte, user string, c packe
return authFailure, nil, errors.New("ssh: extra data following keyboard-interactive pairs")
}
answers, err := cb(msg.User, msg.Instruction, prompts, echos)
answers, err := cb(msg.Name, msg.Instruction, prompts, echos)
if err != nil {
return authFailure, nil, err
}
@@ -497,9 +581,9 @@ type retryableAuthMethod struct {
maxTries int
}
func (r *retryableAuthMethod) auth(session []byte, user string, c packetConn, rand io.Reader) (ok authResult, methods []string, err error) {
func (r *retryableAuthMethod) auth(session []byte, user string, c packetConn, rand io.Reader, extensions map[string][]byte) (ok authResult, methods []string, err error) {
for i := 0; r.maxTries <= 0 || i < r.maxTries; i++ {
ok, methods, err = r.authMethod.auth(session, user, c, rand)
ok, methods, err = r.authMethod.auth(session, user, c, rand, extensions)
if ok != authFailure || err != nil { // either success, partial success or error terminate
return ok, methods, err
}
@@ -542,7 +626,7 @@ type gssAPIWithMICCallback struct {
target string
}
func (g *gssAPIWithMICCallback) auth(session []byte, user string, c packetConn, rand io.Reader) (authResult, []string, error) {
func (g *gssAPIWithMICCallback) auth(session []byte, user string, c packetConn, rand io.Reader, _ map[string][]byte) (authResult, []string, error) {
m := &userAuthRequestMsg{
User: user,
Service: serviceSSH,

View File

@@ -10,6 +10,7 @@ import (
"fmt"
"io"
"math"
"strings"
"sync"
_ "crypto/sha1"
@@ -44,11 +45,11 @@ var preferredCiphers = []string{
// supportedKexAlgos specifies the supported key-exchange algorithms in
// preference order.
var supportedKexAlgos = []string{
kexAlgoCurve25519SHA256,
kexAlgoCurve25519SHA256, kexAlgoCurve25519SHA256LibSSH,
// P384 and P521 are not constant-time yet, but since we don't
// reuse ephemeral keys, using them for ECDH should be OK.
kexAlgoECDH256, kexAlgoECDH384, kexAlgoECDH521,
kexAlgoDH14SHA1, kexAlgoDH1SHA1,
kexAlgoDH14SHA256, kexAlgoDH14SHA1, kexAlgoDH1SHA1,
}
// serverForbiddenKexAlgos contains key exchange algorithms, that are forbidden
@@ -61,18 +62,20 @@ var serverForbiddenKexAlgos = map[string]struct{}{
// preferredKexAlgos specifies the default preference for key-exchange algorithms
// in preference order.
var preferredKexAlgos = []string{
kexAlgoCurve25519SHA256,
kexAlgoCurve25519SHA256, kexAlgoCurve25519SHA256LibSSH,
kexAlgoECDH256, kexAlgoECDH384, kexAlgoECDH521,
kexAlgoDH14SHA1,
kexAlgoDH14SHA256, kexAlgoDH14SHA1,
}
// supportedHostKeyAlgos specifies the supported host-key algorithms (i.e. methods
// of authenticating servers) in preference order.
var supportedHostKeyAlgos = []string{
CertAlgoRSASHA512v01, CertAlgoRSASHA256v01,
CertAlgoRSAv01, CertAlgoDSAv01, CertAlgoECDSA256v01,
CertAlgoECDSA384v01, CertAlgoECDSA521v01, CertAlgoED25519v01,
KeyAlgoECDSA256, KeyAlgoECDSA384, KeyAlgoECDSA521,
KeyAlgoRSASHA512, KeyAlgoRSASHA256,
KeyAlgoRSA, KeyAlgoDSA,
KeyAlgoED25519,
@@ -87,21 +90,49 @@ var supportedMACs = []string{
var supportedCompressions = []string{compressionNone}
// hashFuncs keeps the mapping of supported algorithms to their respective
// hashes needed for signature verification.
// hashFuncs keeps the mapping of supported signature algorithms to their
// respective hashes needed for signing and verification.
var hashFuncs = map[string]crypto.Hash{
KeyAlgoRSA: crypto.SHA1,
KeyAlgoDSA: crypto.SHA1,
KeyAlgoECDSA256: crypto.SHA256,
KeyAlgoECDSA384: crypto.SHA384,
KeyAlgoECDSA521: crypto.SHA512,
CertAlgoRSAv01: crypto.SHA1,
CertAlgoDSAv01: crypto.SHA1,
CertAlgoECDSA256v01: crypto.SHA256,
CertAlgoECDSA384v01: crypto.SHA384,
CertAlgoECDSA521v01: crypto.SHA512,
KeyAlgoRSA: crypto.SHA1,
KeyAlgoRSASHA256: crypto.SHA256,
KeyAlgoRSASHA512: crypto.SHA512,
KeyAlgoDSA: crypto.SHA1,
KeyAlgoECDSA256: crypto.SHA256,
KeyAlgoECDSA384: crypto.SHA384,
KeyAlgoECDSA521: crypto.SHA512,
// KeyAlgoED25519 doesn't pre-hash.
KeyAlgoSKECDSA256: crypto.SHA256,
KeyAlgoSKED25519: crypto.SHA256,
}
// algorithmsForKeyFormat returns the supported signature algorithms for a given
// public key format (PublicKey.Type), in order of preference. See RFC 8332,
// Section 2. See also the note in sendKexInit on backwards compatibility.
func algorithmsForKeyFormat(keyFormat string) []string {
switch keyFormat {
case KeyAlgoRSA:
return []string{KeyAlgoRSASHA256, KeyAlgoRSASHA512, KeyAlgoRSA}
case CertAlgoRSAv01:
return []string{CertAlgoRSASHA256v01, CertAlgoRSASHA512v01, CertAlgoRSAv01}
default:
return []string{keyFormat}
}
}
// supportedPubKeyAuthAlgos specifies the supported client public key
// authentication algorithms. Note that this doesn't include certificate types
// since those use the underlying algorithm. This list is sent to the client if
// it supports the server-sig-algs extension. Order is irrelevant.
var supportedPubKeyAuthAlgos = []string{
KeyAlgoED25519,
KeyAlgoSKED25519, KeyAlgoSKECDSA256,
KeyAlgoECDSA256, KeyAlgoECDSA384, KeyAlgoECDSA521,
KeyAlgoRSASHA256, KeyAlgoRSASHA512, KeyAlgoRSA,
KeyAlgoDSA,
}
var supportedPubKeyAuthAlgosList = strings.Join(supportedPubKeyAuthAlgos, ",")
// unexpectedMessageError results when the SSH message that we received didn't
// match what we wanted.
func unexpectedMessageError(expected, got uint8) error {
@@ -133,7 +164,7 @@ type directionAlgorithms struct {
// rekeyBytes returns a rekeying intervals in bytes.
func (a *directionAlgorithms) rekeyBytes() int64 {
// According to RFC4344 block ciphers should rekey after
// According to RFC 4344 block ciphers should rekey after
// 2^(BLOCKSIZE/4) blocks. For all AES flavors BLOCKSIZE is
// 128.
switch a.Cipher {
@@ -142,10 +173,15 @@ func (a *directionAlgorithms) rekeyBytes() int64 {
}
// For others, stick with RFC4253 recommendation to rekey after 1 Gb of data.
// For others, stick with RFC 4253 recommendation to rekey after 1 Gb of data.
return 1 << 30
}
var aeadCiphers = map[string]bool{
gcmCipherID: true,
chacha20Poly1305ID: true,
}
type algorithms struct {
kex string
hostKey string
@@ -181,14 +217,18 @@ func findAgreedAlgorithms(isClient bool, clientKexInit, serverKexInit *kexInitMs
return
}
ctos.MAC, err = findCommon("client to server MAC", clientKexInit.MACsClientServer, serverKexInit.MACsClientServer)
if err != nil {
return
if !aeadCiphers[ctos.Cipher] {
ctos.MAC, err = findCommon("client to server MAC", clientKexInit.MACsClientServer, serverKexInit.MACsClientServer)
if err != nil {
return
}
}
stoc.MAC, err = findCommon("server to client MAC", clientKexInit.MACsServerClient, serverKexInit.MACsServerClient)
if err != nil {
return
if !aeadCiphers[stoc.Cipher] {
stoc.MAC, err = findCommon("server to client MAC", clientKexInit.MACsServerClient, serverKexInit.MACsServerClient)
if err != nil {
return
}
}
ctos.Compression, err = findCommon("client to server compression", clientKexInit.CompressionClientServer, serverKexInit.CompressionClientServer)
@@ -272,8 +312,9 @@ func (c *Config) SetDefaults() {
}
// buildDataSignedForAuth returns the data that is signed in order to prove
// possession of a private key. See RFC 4252, section 7.
func buildDataSignedForAuth(sessionID []byte, req userAuthRequestMsg, algo, pubKey []byte) []byte {
// possession of a private key. See RFC 4252, section 7. algo is the advertised
// algorithm, and may be a certificate type.
func buildDataSignedForAuth(sessionID []byte, req userAuthRequestMsg, algo string, pubKey []byte) []byte {
data := struct {
Session []byte
Type byte
@@ -281,7 +322,7 @@ func buildDataSignedForAuth(sessionID []byte, req userAuthRequestMsg, algo, pubK
Service string
Method string
Sign bool
Algo []byte
Algo string
PubKey []byte
}{
sessionID,

View File

@@ -52,7 +52,7 @@ type Conn interface {
// SendRequest sends a global request, and returns the
// reply. If wantReply is true, it returns the response status
// and payload. See also RFC4254, section 4.
// and payload. See also RFC 4254, section 4.
SendRequest(name string, wantReply bool, payload []byte) (bool, []byte, error)
// OpenChannel tries to open an channel. If the request is

View File

@@ -12,8 +12,9 @@ the multiplexed nature of SSH is exposed to users that wish to support
others.
References:
[PROTOCOL.certkeys]: http://cvsweb.openbsd.org/cgi-bin/cvsweb/src/usr.bin/ssh/PROTOCOL.certkeys?rev=HEAD
[SSH-PARAMETERS]: http://www.iana.org/assignments/ssh-parameters/ssh-parameters.xml#ssh-parameters-1
[PROTOCOL.certkeys]: http://cvsweb.openbsd.org/cgi-bin/cvsweb/src/usr.bin/ssh/PROTOCOL.certkeys?rev=HEAD
[SSH-PARAMETERS]: http://www.iana.org/assignments/ssh-parameters/ssh-parameters.xml#ssh-parameters-1
This package does not fall under the stability promise of the Go language itself,
so its API may be changed when pressing needs arise.

View File

@@ -58,11 +58,13 @@ type handshakeTransport struct {
incoming chan []byte
readError error
mu sync.Mutex
writeError error
sentInitPacket []byte
sentInitMsg *kexInitMsg
pendingPackets [][]byte // Used when a key exchange is in progress.
mu sync.Mutex
writeError error
sentInitPacket []byte
sentInitMsg *kexInitMsg
pendingPackets [][]byte // Used when a key exchange is in progress.
writePacketsLeft uint32
writeBytesLeft int64
// If the read loop wants to schedule a kex, it pings this
// channel, and the write loop will send out a kex
@@ -71,7 +73,8 @@ type handshakeTransport struct {
// If the other side requests or confirms a kex, its kexInit
// packet is sent here for the write loop to find it.
startKex chan *pendingKex
startKex chan *pendingKex
kexLoopDone chan struct{} // closed (with writeError non-nil) when kexLoop exits
// data for host key checking
hostKeyCallback HostKeyCallback
@@ -86,12 +89,10 @@ type handshakeTransport struct {
// Algorithms agreed in the last key exchange.
algorithms *algorithms
// Counters exclusively owned by readLoop.
readPacketsLeft uint32
readBytesLeft int64
writePacketsLeft uint32
writeBytesLeft int64
// The session ID or nil if first kex did not complete yet.
sessionID []byte
}
@@ -108,7 +109,8 @@ func newHandshakeTransport(conn keyingTransport, config *Config, clientVersion,
clientVersion: clientVersion,
incoming: make(chan []byte, chanSize),
requestKex: make(chan struct{}, 1),
startKex: make(chan *pendingKex, 1),
startKex: make(chan *pendingKex),
kexLoopDone: make(chan struct{}),
config: config,
}
@@ -340,16 +342,17 @@ write:
t.mu.Unlock()
}
// drain startKex channel. We don't service t.requestKex
// because nobody does blocking sends there.
go func() {
for init := range t.startKex {
init.done <- t.writeError
}
}()
// Unblock reader.
t.conn.Close()
// drain startKex channel. We don't service t.requestKex
// because nobody does blocking sends there.
for request := range t.startKex {
request.done <- t.getWriteError()
}
// Mark that the loop is done so that Close can return.
close(t.kexLoopDone)
}
// The protocol uses uint32 for packet counters, so we can't let them
@@ -455,14 +458,38 @@ func (t *handshakeTransport) sendKexInit() error {
}
io.ReadFull(rand.Reader, msg.Cookie[:])
if len(t.hostKeys) > 0 {
isServer := len(t.hostKeys) > 0
if isServer {
for _, k := range t.hostKeys {
msg.ServerHostKeyAlgos = append(
msg.ServerHostKeyAlgos, k.PublicKey().Type())
// If k is an AlgorithmSigner, presume it supports all signature algorithms
// associated with the key format. (Ideally AlgorithmSigner would have a
// method to advertise supported algorithms, but it doesn't. This means that
// adding support for a new algorithm is a breaking change, as we will
// immediately negotiate it even if existing implementations don't support
// it. If that ever happens, we'll have to figure something out.)
// If k is not an AlgorithmSigner, we can only assume it only supports the
// algorithms that matches the key format. (This means that Sign can't pick
// a different default.)
keyFormat := k.PublicKey().Type()
if _, ok := k.(AlgorithmSigner); ok {
msg.ServerHostKeyAlgos = append(msg.ServerHostKeyAlgos, algorithmsForKeyFormat(keyFormat)...)
} else {
msg.ServerHostKeyAlgos = append(msg.ServerHostKeyAlgos, keyFormat)
}
}
} else {
msg.ServerHostKeyAlgos = t.hostKeyAlgorithms
// As a client we opt in to receiving SSH_MSG_EXT_INFO so we know what
// algorithms the server supports for public key authentication. See RFC
// 8308, Section 2.1.
if firstKeyExchange := t.sessionID == nil; firstKeyExchange {
msg.KexAlgos = make([]string, 0, len(t.config.KeyExchanges)+1)
msg.KexAlgos = append(msg.KexAlgos, t.config.KeyExchanges...)
msg.KexAlgos = append(msg.KexAlgos, "ext-info-c")
}
}
packet := Marshal(msg)
// writePacket destroys the contents, so save a copy.
@@ -521,7 +548,16 @@ func (t *handshakeTransport) writePacket(p []byte) error {
}
func (t *handshakeTransport) Close() error {
return t.conn.Close()
// Close the connection. This should cause the readLoop goroutine to wake up
// and close t.startKex, which will shut down kexLoop if running.
err := t.conn.Close()
// Wait for the kexLoop goroutine to complete.
// At that point we know that the readLoop goroutine is complete too,
// because kexLoop itself waits for readLoop to close the startKex channel.
<-t.kexLoopDone
return err
}
func (t *handshakeTransport) enterKeyExchange(otherInitPacket []byte) error {
@@ -582,16 +618,17 @@ func (t *handshakeTransport) enterKeyExchange(otherInitPacket []byte) error {
var result *kexResult
if len(t.hostKeys) > 0 {
result, err = t.server(kex, t.algorithms, &magics)
result, err = t.server(kex, &magics)
} else {
result, err = t.client(kex, t.algorithms, &magics)
result, err = t.client(kex, &magics)
}
if err != nil {
return err
}
if t.sessionID == nil {
firstKeyExchange := t.sessionID == nil
if firstKeyExchange {
t.sessionID = result.H
}
result.SessionID = t.sessionID
@@ -602,6 +639,24 @@ func (t *handshakeTransport) enterKeyExchange(otherInitPacket []byte) error {
if err = t.conn.writePacket([]byte{msgNewKeys}); err != nil {
return err
}
// On the server side, after the first SSH_MSG_NEWKEYS, send a SSH_MSG_EXT_INFO
// message with the server-sig-algs extension if the client supports it. See
// RFC 8308, Sections 2.4 and 3.1.
if !isClient && firstKeyExchange && contains(clientInit.KexAlgos, "ext-info-c") {
extInfo := &extInfoMsg{
NumExtensions: 1,
Payload: make([]byte, 0, 4+15+4+len(supportedPubKeyAuthAlgosList)),
}
extInfo.Payload = appendInt(extInfo.Payload, len("server-sig-algs"))
extInfo.Payload = append(extInfo.Payload, "server-sig-algs"...)
extInfo.Payload = appendInt(extInfo.Payload, len(supportedPubKeyAuthAlgosList))
extInfo.Payload = append(extInfo.Payload, supportedPubKeyAuthAlgosList...)
if err := t.conn.writePacket(Marshal(extInfo)); err != nil {
return err
}
}
if packet, err := t.conn.readPacket(); err != nil {
return err
} else if packet[0] != msgNewKeys {
@@ -611,19 +666,52 @@ func (t *handshakeTransport) enterKeyExchange(otherInitPacket []byte) error {
return nil
}
func (t *handshakeTransport) server(kex kexAlgorithm, algs *algorithms, magics *handshakeMagics) (*kexResult, error) {
var hostKey Signer
for _, k := range t.hostKeys {
if algs.hostKey == k.PublicKey().Type() {
hostKey = k
// algorithmSignerWrapper is an AlgorithmSigner that only supports the default
// key format algorithm.
//
// This is technically a violation of the AlgorithmSigner interface, but it
// should be unreachable given where we use this. Anyway, at least it returns an
// error instead of panicing or producing an incorrect signature.
type algorithmSignerWrapper struct {
Signer
}
func (a algorithmSignerWrapper) SignWithAlgorithm(rand io.Reader, data []byte, algorithm string) (*Signature, error) {
if algorithm != underlyingAlgo(a.PublicKey().Type()) {
return nil, errors.New("ssh: internal error: algorithmSignerWrapper invoked with non-default algorithm")
}
return a.Sign(rand, data)
}
func pickHostKey(hostKeys []Signer, algo string) AlgorithmSigner {
for _, k := range hostKeys {
if algo == k.PublicKey().Type() {
return algorithmSignerWrapper{k}
}
k, ok := k.(AlgorithmSigner)
if !ok {
continue
}
for _, a := range algorithmsForKeyFormat(k.PublicKey().Type()) {
if algo == a {
return k
}
}
}
return nil
}
r, err := kex.Server(t.conn, t.config.Rand, magics, hostKey)
func (t *handshakeTransport) server(kex kexAlgorithm, magics *handshakeMagics) (*kexResult, error) {
hostKey := pickHostKey(t.hostKeys, t.algorithms.hostKey)
if hostKey == nil {
return nil, errors.New("ssh: internal error: negotiated unsupported signature type")
}
r, err := kex.Server(t.conn, t.config.Rand, magics, hostKey, t.algorithms.hostKey)
return r, err
}
func (t *handshakeTransport) client(kex kexAlgorithm, algs *algorithms, magics *handshakeMagics) (*kexResult, error) {
func (t *handshakeTransport) client(kex kexAlgorithm, magics *handshakeMagics) (*kexResult, error) {
result, err := kex.Client(t.conn, t.config.Rand, magics)
if err != nil {
return nil, err
@@ -634,7 +722,7 @@ func (t *handshakeTransport) client(kex kexAlgorithm, algs *algorithms, magics *
return nil, err
}
if err := verifyHostKeySignature(hostKey, result); err != nil {
if err := verifyHostKeySignature(hostKey, t.algorithms.hostKey, result); err != nil {
return nil, err
}

186
vendor/golang.org/x/crypto/ssh/kex.go generated vendored
View File

@@ -20,12 +20,14 @@ import (
)
const (
kexAlgoDH1SHA1 = "diffie-hellman-group1-sha1"
kexAlgoDH14SHA1 = "diffie-hellman-group14-sha1"
kexAlgoECDH256 = "ecdh-sha2-nistp256"
kexAlgoECDH384 = "ecdh-sha2-nistp384"
kexAlgoECDH521 = "ecdh-sha2-nistp521"
kexAlgoCurve25519SHA256 = "curve25519-sha256@libssh.org"
kexAlgoDH1SHA1 = "diffie-hellman-group1-sha1"
kexAlgoDH14SHA1 = "diffie-hellman-group14-sha1"
kexAlgoDH14SHA256 = "diffie-hellman-group14-sha256"
kexAlgoECDH256 = "ecdh-sha2-nistp256"
kexAlgoECDH384 = "ecdh-sha2-nistp384"
kexAlgoECDH521 = "ecdh-sha2-nistp521"
kexAlgoCurve25519SHA256LibSSH = "curve25519-sha256@libssh.org"
kexAlgoCurve25519SHA256 = "curve25519-sha256"
// For the following kex only the client half contains a production
// ready implementation. The server half only consists of a minimal
@@ -75,8 +77,9 @@ func (m *handshakeMagics) write(w io.Writer) {
// kexAlgorithm abstracts different key exchange algorithms.
type kexAlgorithm interface {
// Server runs server-side key agreement, signing the result
// with a hostkey.
Server(p packetConn, rand io.Reader, magics *handshakeMagics, s Signer) (*kexResult, error)
// with a hostkey. algo is the negotiated algorithm, and may
// be a certificate type.
Server(p packetConn, rand io.Reader, magics *handshakeMagics, s AlgorithmSigner, algo string) (*kexResult, error)
// Client runs the client-side key agreement. Caller is
// responsible for verifying the host key signature.
@@ -86,6 +89,7 @@ type kexAlgorithm interface {
// dhGroup is a multiplicative group suitable for implementing Diffie-Hellman key agreement.
type dhGroup struct {
g, p, pMinus1 *big.Int
hashFunc crypto.Hash
}
func (group *dhGroup) diffieHellman(theirPublic, myPrivate *big.Int) (*big.Int, error) {
@@ -96,8 +100,6 @@ func (group *dhGroup) diffieHellman(theirPublic, myPrivate *big.Int) (*big.Int,
}
func (group *dhGroup) Client(c packetConn, randSource io.Reader, magics *handshakeMagics) (*kexResult, error) {
hashFunc := crypto.SHA1
var x *big.Int
for {
var err error
@@ -132,7 +134,7 @@ func (group *dhGroup) Client(c packetConn, randSource io.Reader, magics *handsha
return nil, err
}
h := hashFunc.New()
h := group.hashFunc.New()
magics.write(h)
writeString(h, kexDHReply.HostKey)
writeInt(h, X)
@@ -146,12 +148,11 @@ func (group *dhGroup) Client(c packetConn, randSource io.Reader, magics *handsha
K: K,
HostKey: kexDHReply.HostKey,
Signature: kexDHReply.Signature,
Hash: crypto.SHA1,
Hash: group.hashFunc,
}, nil
}
func (group *dhGroup) Server(c packetConn, randSource io.Reader, magics *handshakeMagics, priv Signer) (result *kexResult, err error) {
hashFunc := crypto.SHA1
func (group *dhGroup) Server(c packetConn, randSource io.Reader, magics *handshakeMagics, priv AlgorithmSigner, algo string) (result *kexResult, err error) {
packet, err := c.readPacket()
if err != nil {
return
@@ -179,7 +180,7 @@ func (group *dhGroup) Server(c packetConn, randSource io.Reader, magics *handsha
hostKeyBytes := priv.PublicKey().Marshal()
h := hashFunc.New()
h := group.hashFunc.New()
magics.write(h)
writeString(h, hostKeyBytes)
writeInt(h, kexDHInit.X)
@@ -193,7 +194,7 @@ func (group *dhGroup) Server(c packetConn, randSource io.Reader, magics *handsha
// H is already a hash, but the hostkey signing will apply its
// own key-specific hash algorithm.
sig, err := signAndMarshal(priv, randSource, H)
sig, err := signAndMarshal(priv, randSource, H, algo)
if err != nil {
return nil, err
}
@@ -211,7 +212,7 @@ func (group *dhGroup) Server(c packetConn, randSource io.Reader, magics *handsha
K: K,
HostKey: hostKeyBytes,
Signature: sig,
Hash: crypto.SHA1,
Hash: group.hashFunc,
}, err
}
@@ -314,7 +315,7 @@ func validateECPublicKey(curve elliptic.Curve, x, y *big.Int) bool {
return true
}
func (kex *ecdh) Server(c packetConn, rand io.Reader, magics *handshakeMagics, priv Signer) (result *kexResult, err error) {
func (kex *ecdh) Server(c packetConn, rand io.Reader, magics *handshakeMagics, priv AlgorithmSigner, algo string) (result *kexResult, err error) {
packet, err := c.readPacket()
if err != nil {
return nil, err
@@ -359,7 +360,7 @@ func (kex *ecdh) Server(c packetConn, rand io.Reader, magics *handshakeMagics, p
// H is already a hash, but the hostkey signing will apply its
// own key-specific hash algorithm.
sig, err := signAndMarshal(priv, rand, H)
sig, err := signAndMarshal(priv, rand, H, algo)
if err != nil {
return nil, err
}
@@ -384,39 +385,62 @@ func (kex *ecdh) Server(c packetConn, rand io.Reader, magics *handshakeMagics, p
}, nil
}
// ecHash returns the hash to match the given elliptic curve, see RFC
// 5656, section 6.2.1
func ecHash(curve elliptic.Curve) crypto.Hash {
bitSize := curve.Params().BitSize
switch {
case bitSize <= 256:
return crypto.SHA256
case bitSize <= 384:
return crypto.SHA384
}
return crypto.SHA512
}
var kexAlgoMap = map[string]kexAlgorithm{}
func init() {
// This is the group called diffie-hellman-group1-sha1 in RFC
// 4253 and Oakley Group 2 in RFC 2409.
// This is the group called diffie-hellman-group1-sha1 in
// RFC 4253 and Oakley Group 2 in RFC 2409.
p, _ := new(big.Int).SetString("FFFFFFFFFFFFFFFFC90FDAA22168C234C4C6628B80DC1CD129024E088A67CC74020BBEA63B139B22514A08798E3404DDEF9519B3CD3A431B302B0A6DF25F14374FE1356D6D51C245E485B576625E7EC6F44C42E9A637ED6B0BFF5CB6F406B7EDEE386BFB5A899FA5AE9F24117C4B1FE649286651ECE65381FFFFFFFFFFFFFFFF", 16)
kexAlgoMap[kexAlgoDH1SHA1] = &dhGroup{
g: new(big.Int).SetInt64(2),
p: p,
pMinus1: new(big.Int).Sub(p, bigOne),
hashFunc: crypto.SHA1,
}
// This are the groups called diffie-hellman-group14-sha1 and
// diffie-hellman-group14-sha256 in RFC 4253 and RFC 8268,
// and Oakley Group 14 in RFC 3526.
p, _ = new(big.Int).SetString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
group14 := &dhGroup{
g: new(big.Int).SetInt64(2),
p: p,
pMinus1: new(big.Int).Sub(p, bigOne),
}
// This is the group called diffie-hellman-group14-sha1 in RFC
// 4253 and Oakley Group 14 in RFC 3526.
p, _ = new(big.Int).SetString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
kexAlgoMap[kexAlgoDH14SHA1] = &dhGroup{
g: new(big.Int).SetInt64(2),
p: p,
pMinus1: new(big.Int).Sub(p, bigOne),
g: group14.g, p: group14.p, pMinus1: group14.pMinus1,
hashFunc: crypto.SHA1,
}
kexAlgoMap[kexAlgoDH14SHA256] = &dhGroup{
g: group14.g, p: group14.p, pMinus1: group14.pMinus1,
hashFunc: crypto.SHA256,
}
kexAlgoMap[kexAlgoECDH521] = &ecdh{elliptic.P521()}
kexAlgoMap[kexAlgoECDH384] = &ecdh{elliptic.P384()}
kexAlgoMap[kexAlgoECDH256] = &ecdh{elliptic.P256()}
kexAlgoMap[kexAlgoCurve25519SHA256] = &curve25519sha256{}
kexAlgoMap[kexAlgoCurve25519SHA256LibSSH] = &curve25519sha256{}
kexAlgoMap[kexAlgoDHGEXSHA1] = &dhGEXSHA{hashFunc: crypto.SHA1}
kexAlgoMap[kexAlgoDHGEXSHA256] = &dhGEXSHA{hashFunc: crypto.SHA256}
}
// curve25519sha256 implements the curve25519-sha256@libssh.org key
// agreement protocol, as described in
// https://git.libssh.org/projects/libssh.git/tree/doc/curve25519-sha256@libssh.org.txt
// curve25519sha256 implements the curve25519-sha256 (formerly known as
// curve25519-sha256@libssh.org) key exchange method, as described in RFC 8731.
type curve25519sha256 struct{}
type curve25519KeyPair struct {
@@ -486,7 +510,7 @@ func (kex *curve25519sha256) Client(c packetConn, rand io.Reader, magics *handsh
}, nil
}
func (kex *curve25519sha256) Server(c packetConn, rand io.Reader, magics *handshakeMagics, priv Signer) (result *kexResult, err error) {
func (kex *curve25519sha256) Server(c packetConn, rand io.Reader, magics *handshakeMagics, priv AlgorithmSigner, algo string) (result *kexResult, err error) {
packet, err := c.readPacket()
if err != nil {
return
@@ -527,7 +551,7 @@ func (kex *curve25519sha256) Server(c packetConn, rand io.Reader, magics *handsh
H := h.Sum(nil)
sig, err := signAndMarshal(priv, rand, H)
sig, err := signAndMarshal(priv, rand, H, algo)
if err != nil {
return nil, err
}
@@ -553,7 +577,6 @@ func (kex *curve25519sha256) Server(c packetConn, rand io.Reader, magics *handsh
// diffie-hellman-group-exchange-sha256 key agreement protocols,
// as described in RFC 4419
type dhGEXSHA struct {
g, p *big.Int
hashFunc crypto.Hash
}
@@ -563,14 +586,7 @@ const (
dhGroupExchangeMaximumBits = 8192
)
func (gex *dhGEXSHA) diffieHellman(theirPublic, myPrivate *big.Int) (*big.Int, error) {
if theirPublic.Sign() <= 0 || theirPublic.Cmp(gex.p) >= 0 {
return nil, fmt.Errorf("ssh: DH parameter out of bounds")
}
return new(big.Int).Exp(theirPublic, myPrivate, gex.p), nil
}
func (gex dhGEXSHA) Client(c packetConn, randSource io.Reader, magics *handshakeMagics) (*kexResult, error) {
func (gex *dhGEXSHA) Client(c packetConn, randSource io.Reader, magics *handshakeMagics) (*kexResult, error) {
// Send GexRequest
kexDHGexRequest := kexDHGexRequestMsg{
MinBits: dhGroupExchangeMinimumBits,
@@ -587,35 +603,29 @@ func (gex dhGEXSHA) Client(c packetConn, randSource io.Reader, magics *handshake
return nil, err
}
var kexDHGexGroup kexDHGexGroupMsg
if err = Unmarshal(packet, &kexDHGexGroup); err != nil {
var msg kexDHGexGroupMsg
if err = Unmarshal(packet, &msg); err != nil {
return nil, err
}
// reject if p's bit length < dhGroupExchangeMinimumBits or > dhGroupExchangeMaximumBits
if kexDHGexGroup.P.BitLen() < dhGroupExchangeMinimumBits || kexDHGexGroup.P.BitLen() > dhGroupExchangeMaximumBits {
return nil, fmt.Errorf("ssh: server-generated gex p is out of range (%d bits)", kexDHGexGroup.P.BitLen())
if msg.P.BitLen() < dhGroupExchangeMinimumBits || msg.P.BitLen() > dhGroupExchangeMaximumBits {
return nil, fmt.Errorf("ssh: server-generated gex p is out of range (%d bits)", msg.P.BitLen())
}
gex.p = kexDHGexGroup.P
gex.g = kexDHGexGroup.G
// Check if g is safe by verifing that g > 1 and g < p - 1
one := big.NewInt(1)
var pMinusOne = &big.Int{}
pMinusOne.Sub(gex.p, one)
if gex.g.Cmp(one) != 1 && gex.g.Cmp(pMinusOne) != -1 {
// Check if g is safe by verifying that 1 < g < p-1
pMinusOne := new(big.Int).Sub(msg.P, bigOne)
if msg.G.Cmp(bigOne) <= 0 || msg.G.Cmp(pMinusOne) >= 0 {
return nil, fmt.Errorf("ssh: server provided gex g is not safe")
}
// Send GexInit
var pHalf = &big.Int{}
pHalf.Rsh(gex.p, 1)
pHalf := new(big.Int).Rsh(msg.P, 1)
x, err := rand.Int(randSource, pHalf)
if err != nil {
return nil, err
}
X := new(big.Int).Exp(gex.g, x, gex.p)
X := new(big.Int).Exp(msg.G, x, msg.P)
kexDHGexInit := kexDHGexInitMsg{
X: X,
}
@@ -634,13 +644,13 @@ func (gex dhGEXSHA) Client(c packetConn, randSource io.Reader, magics *handshake
return nil, err
}
kInt, err := gex.diffieHellman(kexDHGexReply.Y, x)
if err != nil {
return nil, err
if kexDHGexReply.Y.Cmp(bigOne) <= 0 || kexDHGexReply.Y.Cmp(pMinusOne) >= 0 {
return nil, errors.New("ssh: DH parameter out of bounds")
}
kInt := new(big.Int).Exp(kexDHGexReply.Y, x, msg.P)
// Check if k is safe by verifing that k > 1 and k < p - 1
if kInt.Cmp(one) != 1 && kInt.Cmp(pMinusOne) != -1 {
// Check if k is safe by verifying that k > 1 and k < p - 1
if kInt.Cmp(bigOne) <= 0 || kInt.Cmp(pMinusOne) >= 0 {
return nil, fmt.Errorf("ssh: derived k is not safe")
}
@@ -650,8 +660,8 @@ func (gex dhGEXSHA) Client(c packetConn, randSource io.Reader, magics *handshake
binary.Write(h, binary.BigEndian, uint32(dhGroupExchangeMinimumBits))
binary.Write(h, binary.BigEndian, uint32(dhGroupExchangePreferredBits))
binary.Write(h, binary.BigEndian, uint32(dhGroupExchangeMaximumBits))
writeInt(h, gex.p)
writeInt(h, gex.g)
writeInt(h, msg.P)
writeInt(h, msg.G)
writeInt(h, X)
writeInt(h, kexDHGexReply.Y)
K := make([]byte, intLength(kInt))
@@ -670,7 +680,7 @@ func (gex dhGEXSHA) Client(c packetConn, randSource io.Reader, magics *handshake
// Server half implementation of the Diffie Hellman Key Exchange with SHA1 and SHA256.
//
// This is a minimal implementation to satisfy the automated tests.
func (gex dhGEXSHA) Server(c packetConn, randSource io.Reader, magics *handshakeMagics, priv Signer) (result *kexResult, err error) {
func (gex dhGEXSHA) Server(c packetConn, randSource io.Reader, magics *handshakeMagics, priv AlgorithmSigner, algo string) (result *kexResult, err error) {
// Receive GexRequest
packet, err := c.readPacket()
if err != nil {
@@ -681,35 +691,17 @@ func (gex dhGEXSHA) Server(c packetConn, randSource io.Reader, magics *handshake
return
}
// smoosh the user's preferred size into our own limits
if kexDHGexRequest.PreferedBits > dhGroupExchangeMaximumBits {
kexDHGexRequest.PreferedBits = dhGroupExchangeMaximumBits
}
if kexDHGexRequest.PreferedBits < dhGroupExchangeMinimumBits {
kexDHGexRequest.PreferedBits = dhGroupExchangeMinimumBits
}
// fix min/max if they're inconsistent. technically, we could just pout
// and hang up, but there's no harm in giving them the benefit of the
// doubt and just picking a bitsize for them.
if kexDHGexRequest.MinBits > kexDHGexRequest.PreferedBits {
kexDHGexRequest.MinBits = kexDHGexRequest.PreferedBits
}
if kexDHGexRequest.MaxBits < kexDHGexRequest.PreferedBits {
kexDHGexRequest.MaxBits = kexDHGexRequest.PreferedBits
}
// Send GexGroup
// This is the group called diffie-hellman-group14-sha1 in RFC
// 4253 and Oakley Group 14 in RFC 3526.
p, _ := new(big.Int).SetString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
gex.p = p
gex.g = big.NewInt(2)
g := big.NewInt(2)
kexDHGexGroup := kexDHGexGroupMsg{
P: gex.p,
G: gex.g,
msg := &kexDHGexGroupMsg{
P: p,
G: g,
}
if err := c.writePacket(Marshal(&kexDHGexGroup)); err != nil {
if err := c.writePacket(Marshal(msg)); err != nil {
return nil, err
}
@@ -723,19 +715,19 @@ func (gex dhGEXSHA) Server(c packetConn, randSource io.Reader, magics *handshake
return
}
var pHalf = &big.Int{}
pHalf.Rsh(gex.p, 1)
pHalf := new(big.Int).Rsh(p, 1)
y, err := rand.Int(randSource, pHalf)
if err != nil {
return
}
Y := new(big.Int).Exp(g, y, p)
Y := new(big.Int).Exp(gex.g, y, gex.p)
kInt, err := gex.diffieHellman(kexDHGexInit.X, y)
if err != nil {
return nil, err
pMinusOne := new(big.Int).Sub(p, bigOne)
if kexDHGexInit.X.Cmp(bigOne) <= 0 || kexDHGexInit.X.Cmp(pMinusOne) >= 0 {
return nil, errors.New("ssh: DH parameter out of bounds")
}
kInt := new(big.Int).Exp(kexDHGexInit.X, y, p)
hostKeyBytes := priv.PublicKey().Marshal()
@@ -745,8 +737,8 @@ func (gex dhGEXSHA) Server(c packetConn, randSource io.Reader, magics *handshake
binary.Write(h, binary.BigEndian, uint32(dhGroupExchangeMinimumBits))
binary.Write(h, binary.BigEndian, uint32(dhGroupExchangePreferredBits))
binary.Write(h, binary.BigEndian, uint32(dhGroupExchangeMaximumBits))
writeInt(h, gex.p)
writeInt(h, gex.g)
writeInt(h, p)
writeInt(h, g)
writeInt(h, kexDHGexInit.X)
writeInt(h, Y)
@@ -758,7 +750,7 @@ func (gex dhGEXSHA) Server(c packetConn, randSource io.Reader, magics *handshake
// H is already a hash, but the hostkey signing will apply its
// own key-specific hash algorithm.
sig, err := signAndMarshal(priv, randSource, H)
sig, err := signAndMarshal(priv, randSource, H, algo)
if err != nil {
return nil, err
}

View File

@@ -30,8 +30,9 @@ import (
"golang.org/x/crypto/ssh/internal/bcrypt_pbkdf"
)
// These constants represent the algorithm names for key types supported by this
// package.
// Public key algorithms names. These values can appear in PublicKey.Type,
// ClientConfig.HostKeyAlgorithms, Signature.Format, or as AlgorithmSigner
// arguments.
const (
KeyAlgoRSA = "ssh-rsa"
KeyAlgoDSA = "ssh-dss"
@@ -41,16 +42,21 @@ const (
KeyAlgoECDSA521 = "ecdsa-sha2-nistp521"
KeyAlgoED25519 = "ssh-ed25519"
KeyAlgoSKED25519 = "sk-ssh-ed25519@openssh.com"
// KeyAlgoRSASHA256 and KeyAlgoRSASHA512 are only public key algorithms, not
// public key formats, so they can't appear as a PublicKey.Type. The
// corresponding PublicKey.Type is KeyAlgoRSA. See RFC 8332, Section 2.
KeyAlgoRSASHA256 = "rsa-sha2-256"
KeyAlgoRSASHA512 = "rsa-sha2-512"
)
// These constants represent non-default signature algorithms that are supported
// as algorithm parameters to AlgorithmSigner.SignWithAlgorithm methods. See
// [PROTOCOL.agent] section 4.5.1 and
// https://tools.ietf.org/html/draft-ietf-curdle-rsa-sha2-10
const (
SigAlgoRSA = "ssh-rsa"
SigAlgoRSASHA2256 = "rsa-sha2-256"
SigAlgoRSASHA2512 = "rsa-sha2-512"
// Deprecated: use KeyAlgoRSA.
SigAlgoRSA = KeyAlgoRSA
// Deprecated: use KeyAlgoRSASHA256.
SigAlgoRSASHA2256 = KeyAlgoRSASHA256
// Deprecated: use KeyAlgoRSASHA512.
SigAlgoRSASHA2512 = KeyAlgoRSASHA512
)
// parsePubKey parses a public key of the given algorithm.
@@ -70,7 +76,7 @@ func parsePubKey(in []byte, algo string) (pubKey PublicKey, rest []byte, err err
case KeyAlgoSKED25519:
return parseSKEd25519(in)
case CertAlgoRSAv01, CertAlgoDSAv01, CertAlgoECDSA256v01, CertAlgoECDSA384v01, CertAlgoECDSA521v01, CertAlgoSKECDSA256v01, CertAlgoED25519v01, CertAlgoSKED25519v01:
cert, err := parseCert(in, certToPrivAlgo(algo))
cert, err := parseCert(in, certKeyAlgoNames[algo])
if err != nil {
return nil, nil, err
}
@@ -178,7 +184,7 @@ func ParseKnownHosts(in []byte) (marker string, hosts []string, pubKey PublicKey
return "", nil, nil, "", nil, io.EOF
}
// ParseAuthorizedKeys parses a public key from an authorized_keys
// ParseAuthorizedKey parses a public key from an authorized_keys
// file used in OpenSSH according to the sshd(8) manual page.
func ParseAuthorizedKey(in []byte) (out PublicKey, comment string, options []string, rest []byte, err error) {
for len(in) > 0 {
@@ -289,18 +295,21 @@ func MarshalAuthorizedKey(key PublicKey) []byte {
return b.Bytes()
}
// PublicKey is an abstraction of different types of public keys.
// PublicKey represents a public key using an unspecified algorithm.
//
// Some PublicKeys provided by this package also implement CryptoPublicKey.
type PublicKey interface {
// Type returns the key's type, e.g. "ssh-rsa".
// Type returns the key format name, e.g. "ssh-rsa".
Type() string
// Marshal returns the serialized key data in SSH wire format,
// with the name prefix. To unmarshal the returned data, use
// the ParsePublicKey function.
// Marshal returns the serialized key data in SSH wire format, with the name
// prefix. To unmarshal the returned data, use the ParsePublicKey function.
Marshal() []byte
// Verify that sig is a signature on the given data using this
// key. This function will hash the data appropriately first.
// Verify that sig is a signature on the given data using this key. This
// method will hash the data appropriately first. sig.Format is allowed to
// be any signature algorithm compatible with the key type, the caller
// should check if it has more stringent requirements.
Verify(data []byte, sig *Signature) error
}
@@ -311,25 +320,32 @@ type CryptoPublicKey interface {
}
// A Signer can create signatures that verify against a public key.
//
// Some Signers provided by this package also implement AlgorithmSigner.
type Signer interface {
// PublicKey returns an associated PublicKey instance.
// PublicKey returns the associated PublicKey.
PublicKey() PublicKey
// Sign returns raw signature for the given data. This method
// will apply the hash specified for the keytype to the data.
// Sign returns a signature for the given data. This method will hash the
// data appropriately first. The signature algorithm is expected to match
// the key format returned by the PublicKey.Type method (and not to be any
// alternative algorithm supported by the key format).
Sign(rand io.Reader, data []byte) (*Signature, error)
}
// A AlgorithmSigner is a Signer that also supports specifying a specific
// algorithm to use for signing.
// An AlgorithmSigner is a Signer that also supports specifying an algorithm to
// use for signing.
//
// An AlgorithmSigner can't advertise the algorithms it supports, so it should
// be prepared to be invoked with every algorithm supported by the public key
// format.
type AlgorithmSigner interface {
Signer
// SignWithAlgorithm is like Signer.Sign, but allows specification of a
// non-default signing algorithm. See the SigAlgo* constants in this
// package for signature algorithms supported by this package. Callers may
// pass an empty string for the algorithm in which case the AlgorithmSigner
// will use its default algorithm.
// SignWithAlgorithm is like Signer.Sign, but allows specifying a desired
// signing algorithm. Callers may pass an empty string for the algorithm in
// which case the AlgorithmSigner will use a default algorithm. This default
// doesn't currently control any behavior in this package.
SignWithAlgorithm(rand io.Reader, data []byte, algorithm string) (*Signature, error)
}
@@ -381,17 +397,11 @@ func (r *rsaPublicKey) Marshal() []byte {
}
func (r *rsaPublicKey) Verify(data []byte, sig *Signature) error {
var hash crypto.Hash
switch sig.Format {
case SigAlgoRSA:
hash = crypto.SHA1
case SigAlgoRSASHA2256:
hash = crypto.SHA256
case SigAlgoRSASHA2512:
hash = crypto.SHA512
default:
supportedAlgos := algorithmsForKeyFormat(r.Type())
if !contains(supportedAlgos, sig.Format) {
return fmt.Errorf("ssh: signature type %s for key type %s", sig.Format, r.Type())
}
hash := hashFuncs[sig.Format]
h := hash.New()
h.Write(data)
digest := h.Sum(nil)
@@ -466,7 +476,7 @@ func (k *dsaPublicKey) Verify(data []byte, sig *Signature) error {
if sig.Format != k.Type() {
return fmt.Errorf("ssh: signature type %s for key type %s", sig.Format, k.Type())
}
h := crypto.SHA1.New()
h := hashFuncs[sig.Format].New()
h.Write(data)
digest := h.Sum(nil)
@@ -499,7 +509,7 @@ func (k *dsaPrivateKey) PublicKey() PublicKey {
}
func (k *dsaPrivateKey) Sign(rand io.Reader, data []byte) (*Signature, error) {
return k.SignWithAlgorithm(rand, data, "")
return k.SignWithAlgorithm(rand, data, k.PublicKey().Type())
}
func (k *dsaPrivateKey) SignWithAlgorithm(rand io.Reader, data []byte, algorithm string) (*Signature, error) {
@@ -507,7 +517,7 @@ func (k *dsaPrivateKey) SignWithAlgorithm(rand io.Reader, data []byte, algorithm
return nil, fmt.Errorf("ssh: unsupported signature algorithm %s", algorithm)
}
h := crypto.SHA1.New()
h := hashFuncs[k.PublicKey().Type()].New()
h.Write(data)
digest := h.Sum(nil)
r, s, err := dsa.Sign(rand, k.PrivateKey, digest)
@@ -603,19 +613,6 @@ func supportedEllipticCurve(curve elliptic.Curve) bool {
return curve == elliptic.P256() || curve == elliptic.P384() || curve == elliptic.P521()
}
// ecHash returns the hash to match the given elliptic curve, see RFC
// 5656, section 6.2.1
func ecHash(curve elliptic.Curve) crypto.Hash {
bitSize := curve.Params().BitSize
switch {
case bitSize <= 256:
return crypto.SHA256
case bitSize <= 384:
return crypto.SHA384
}
return crypto.SHA512
}
// parseECDSA parses an ECDSA key according to RFC 5656, section 3.1.
func parseECDSA(in []byte) (out PublicKey, rest []byte, err error) {
var w struct {
@@ -671,7 +668,7 @@ func (k *ecdsaPublicKey) Verify(data []byte, sig *Signature) error {
return fmt.Errorf("ssh: signature type %s for key type %s", sig.Format, k.Type())
}
h := ecHash(k.Curve).New()
h := hashFuncs[sig.Format].New()
h.Write(data)
digest := h.Sum(nil)
@@ -775,7 +772,7 @@ func (k *skECDSAPublicKey) Verify(data []byte, sig *Signature) error {
return fmt.Errorf("ssh: signature type %s for key type %s", sig.Format, k.Type())
}
h := ecHash(k.Curve).New()
h := hashFuncs[sig.Format].New()
h.Write([]byte(k.application))
appDigest := h.Sum(nil)
@@ -874,7 +871,7 @@ func (k *skEd25519PublicKey) Verify(data []byte, sig *Signature) error {
return fmt.Errorf("invalid size %d for Ed25519 public key", l)
}
h := sha256.New()
h := hashFuncs[sig.Format].New()
h.Write([]byte(k.application))
appDigest := h.Sum(nil)
@@ -961,44 +958,20 @@ func (s *wrappedSigner) PublicKey() PublicKey {
}
func (s *wrappedSigner) Sign(rand io.Reader, data []byte) (*Signature, error) {
return s.SignWithAlgorithm(rand, data, "")
return s.SignWithAlgorithm(rand, data, s.pubKey.Type())
}
func (s *wrappedSigner) SignWithAlgorithm(rand io.Reader, data []byte, algorithm string) (*Signature, error) {
var hashFunc crypto.Hash
if _, ok := s.pubKey.(*rsaPublicKey); ok {
// RSA keys support a few hash functions determined by the requested signature algorithm
switch algorithm {
case "", SigAlgoRSA:
algorithm = SigAlgoRSA
hashFunc = crypto.SHA1
case SigAlgoRSASHA2256:
hashFunc = crypto.SHA256
case SigAlgoRSASHA2512:
hashFunc = crypto.SHA512
default:
return nil, fmt.Errorf("ssh: unsupported signature algorithm %s", algorithm)
}
} else {
// The only supported algorithm for all other key types is the same as the type of the key
if algorithm == "" {
algorithm = s.pubKey.Type()
} else if algorithm != s.pubKey.Type() {
return nil, fmt.Errorf("ssh: unsupported signature algorithm %s", algorithm)
}
switch key := s.pubKey.(type) {
case *dsaPublicKey:
hashFunc = crypto.SHA1
case *ecdsaPublicKey:
hashFunc = ecHash(key.Curve)
case ed25519PublicKey:
default:
return nil, fmt.Errorf("ssh: unsupported key type %T", key)
}
if algorithm == "" {
algorithm = s.pubKey.Type()
}
supportedAlgos := algorithmsForKeyFormat(s.pubKey.Type())
if !contains(supportedAlgos, algorithm) {
return nil, fmt.Errorf("ssh: unsupported signature algorithm %q for key format %q", algorithm, s.pubKey.Type())
}
hashFunc := hashFuncs[algorithm]
var digest []byte
if hashFunc != 0 {
h := hashFunc.New()

View File

@@ -68,7 +68,7 @@ type kexInitMsg struct {
// See RFC 4253, section 8.
// Diffie-Helman
// Diffie-Hellman
const msgKexDHInit = 30
type kexDHInitMsg struct {
@@ -141,6 +141,14 @@ type serviceAcceptMsg struct {
Service string `sshtype:"6"`
}
// See RFC 8308, section 2.3
const msgExtInfo = 7
type extInfoMsg struct {
NumExtensions uint32 `sshtype:"7"`
Payload []byte `ssh:"rest"`
}
// See RFC 4252, section 5.
const msgUserAuthRequest = 50
@@ -180,11 +188,11 @@ const msgUserAuthInfoRequest = 60
const msgUserAuthInfoResponse = 61
type userAuthInfoRequestMsg struct {
User string `sshtype:"60"`
Instruction string
DeprecatedLanguage string
NumPrompts uint32
Prompts []byte `ssh:"rest"`
Name string `sshtype:"60"`
Instruction string
Language string
NumPrompts uint32
Prompts []byte `ssh:"rest"`
}
// See RFC 4254, section 5.1.
@@ -782,6 +790,8 @@ func decode(packet []byte) (interface{}, error) {
msg = new(serviceRequestMsg)
case msgServiceAccept:
msg = new(serviceAcceptMsg)
case msgExtInfo:
msg = new(extInfoMsg)
case msgKexInit:
msg = new(kexInitMsg)
case msgKexDHInit:
@@ -843,6 +853,7 @@ var packetTypeNames = map[byte]string{
msgDisconnect: "disconnectMsg",
msgServiceRequest: "serviceRequestMsg",
msgServiceAccept: "serviceAcceptMsg",
msgExtInfo: "extInfoMsg",
msgKexInit: "kexInitMsg",
msgKexDHInit: "kexDHInitMsg",
msgKexDHReply: "kexDHReplyMsg",

View File

@@ -68,8 +68,16 @@ type ServerConfig struct {
// NoClientAuth is true if clients are allowed to connect without
// authenticating.
// To determine NoClientAuth at runtime, set NoClientAuth to true
// and the optional NoClientAuthCallback to a non-nil value.
NoClientAuth bool
// NoClientAuthCallback, if non-nil, is called when a user
// attempts to authenticate with auth method "none".
// NoClientAuth must also be set to true for this be used, or
// this func is unused.
NoClientAuthCallback func(ConnMetadata) (*Permissions, error)
// MaxAuthTries specifies the maximum number of authentication attempts
// permitted per connection. If set to a negative number, the number of
// attempts are unlimited. If set to zero, the number of attempts are limited
@@ -120,7 +128,7 @@ type ServerConfig struct {
}
// AddHostKey adds a private key as a host key. If an existing host
// key exists with the same algorithm, it is overwritten. Each server
// key exists with the same public key format, it is replaced. Each server
// config must have at least one host key.
func (s *ServerConfig) AddHostKey(key Signer) {
for i, k := range s.hostKeys {
@@ -212,9 +220,10 @@ func NewServerConn(c net.Conn, config *ServerConfig) (*ServerConn, <-chan NewCha
}
// signAndMarshal signs the data with the appropriate algorithm,
// and serializes the result in SSH wire format.
func signAndMarshal(k Signer, rand io.Reader, data []byte) ([]byte, error) {
sig, err := k.Sign(rand, data)
// and serializes the result in SSH wire format. algo is the negotiate
// algorithm and may be a certificate type.
func signAndMarshal(k AlgorithmSigner, rand io.Reader, data []byte, algo string) ([]byte, error) {
sig, err := k.SignWithAlgorithm(rand, data, underlyingAlgo(algo))
if err != nil {
return nil, err
}
@@ -282,15 +291,6 @@ func (s *connection) serverHandshake(config *ServerConfig) (*Permissions, error)
return perms, err
}
func isAcceptableAlgo(algo string) bool {
switch algo {
case KeyAlgoRSA, KeyAlgoDSA, KeyAlgoECDSA256, KeyAlgoECDSA384, KeyAlgoECDSA521, KeyAlgoSKECDSA256, KeyAlgoED25519, KeyAlgoSKED25519,
CertAlgoRSAv01, CertAlgoDSAv01, CertAlgoECDSA256v01, CertAlgoECDSA384v01, CertAlgoECDSA521v01, CertAlgoSKECDSA256v01, CertAlgoED25519v01, CertAlgoSKED25519v01:
return true
}
return false
}
func checkSourceAddress(addr net.Addr, sourceAddrs string) error {
if addr == nil {
return errors.New("ssh: no address known for client, but source-address match required")
@@ -454,7 +454,11 @@ userAuthLoop:
switch userAuthReq.Method {
case "none":
if config.NoClientAuth {
authErr = nil
if config.NoClientAuthCallback != nil {
perms, authErr = config.NoClientAuthCallback(s)
} else {
authErr = nil
}
}
// allow initial attempt of 'none' without penalty
@@ -501,7 +505,7 @@ userAuthLoop:
return nil, parseError(msgUserAuthRequest)
}
algo := string(algoBytes)
if !isAcceptableAlgo(algo) {
if !contains(supportedPubKeyAuthAlgos, underlyingAlgo(algo)) {
authErr = fmt.Errorf("ssh: algorithm %q not accepted", algo)
break
}
@@ -553,16 +557,22 @@ userAuthLoop:
if !ok || len(payload) > 0 {
return nil, parseError(msgUserAuthRequest)
}
// Ensure the public key algo and signature algo
// are supported. Compare the private key
// algorithm name that corresponds to algo with
// sig.Format. This is usually the same, but
// for certs, the names differ.
if !isAcceptableAlgo(sig.Format) {
if !contains(supportedPubKeyAuthAlgos, sig.Format) {
authErr = fmt.Errorf("ssh: algorithm %q not accepted", sig.Format)
break
}
signedData := buildDataSignedForAuth(sessionID, userAuthReq, algoBytes, pubKeyData)
if underlyingAlgo(algo) != sig.Format {
authErr = fmt.Errorf("ssh: signature %q not compatible with selected algorithm %q", sig.Format, algo)
break
}
signedData := buildDataSignedForAuth(sessionID, userAuthReq, algo, pubKeyData)
if err := pubKey.Verify(signedData, sig); err != nil {
return nil, err
@@ -633,6 +643,30 @@ userAuthLoop:
}
authFailures++
if config.MaxAuthTries > 0 && authFailures >= config.MaxAuthTries {
// If we have hit the max attempts, don't bother sending the
// final SSH_MSG_USERAUTH_FAILURE message, since there are
// no more authentication methods which can be attempted,
// and this message may cause the client to re-attempt
// authentication while we send the disconnect message.
// Continue, and trigger the disconnect at the start of
// the loop.
//
// The SSH specification is somewhat confusing about this,
// RFC 4252 Section 5.1 requires each authentication failure
// be responded to with a respective SSH_MSG_USERAUTH_FAILURE
// message, but Section 4 says the server should disconnect
// after some number of attempts, but it isn't explicit which
// message should take precedence (i.e. should there be a failure
// message than a disconnect message, or if we are going to
// disconnect, should we only send that message.)
//
// Either way, OpenSSH disconnects immediately after the last
// failed authnetication attempt, and given they are typically
// considered the golden implementation it seems reasonable
// to match that behavior.
continue
}
var failureMsg userAuthFailureMsg
if config.PasswordCallback != nil {
@@ -670,7 +704,7 @@ type sshClientKeyboardInteractive struct {
*connection
}
func (c *sshClientKeyboardInteractive) Challenge(user, instruction string, questions []string, echos []bool) (answers []string, err error) {
func (c *sshClientKeyboardInteractive) Challenge(name, instruction string, questions []string, echos []bool) (answers []string, err error) {
if len(questions) != len(echos) {
return nil, errors.New("ssh: echos and questions must have equal length")
}
@@ -682,6 +716,7 @@ func (c *sshClientKeyboardInteractive) Challenge(user, instruction string, quest
}
if err := c.transport.writePacket(Marshal(&userAuthInfoRequestMsg{
Name: name,
Instruction: instruction,
NumPrompts: uint32(len(questions)),
Prompts: prompts,

View File

@@ -13,7 +13,6 @@ import (
"errors"
"fmt"
"io"
"io/ioutil"
"sync"
)
@@ -85,6 +84,7 @@ const (
IXANY = 39
IXOFF = 40
IMAXBEL = 41
IUTF8 = 42 // RFC 8160
ISIG = 50
ICANON = 51
XCASE = 52
@@ -123,7 +123,7 @@ type Session struct {
// output and error.
//
// If either is nil, Run connects the corresponding file
// descriptor to an instance of ioutil.Discard. There is a
// descriptor to an instance of io.Discard. There is a
// fixed amount of buffering that is shared for the two streams.
// If either blocks it may eventually cause the remote
// command to block.
@@ -505,7 +505,7 @@ func (s *Session) stdout() {
return
}
if s.Stdout == nil {
s.Stdout = ioutil.Discard
s.Stdout = io.Discard
}
s.copyFuncs = append(s.copyFuncs, func() error {
_, err := io.Copy(s.Stdout, s.ch)
@@ -518,7 +518,7 @@ func (s *Session) stderr() {
return
}
if s.Stderr == nil {
s.Stderr = ioutil.Discard
s.Stderr = io.Discard
}
s.copyFuncs = append(s.copyFuncs, func() error {
_, err := io.Copy(s.Stderr, s.ch.Stderr())

View File

@@ -238,15 +238,19 @@ var (
// (to setup server->client keys) or clientKeys (for client->server keys).
func newPacketCipher(d direction, algs directionAlgorithms, kex *kexResult) (packetCipher, error) {
cipherMode := cipherModes[algs.Cipher]
macMode := macModes[algs.MAC]
iv := make([]byte, cipherMode.ivSize)
key := make([]byte, cipherMode.keySize)
macKey := make([]byte, macMode.keySize)
generateKeyMaterial(iv, d.ivTag, kex)
generateKeyMaterial(key, d.keyTag, kex)
generateKeyMaterial(macKey, d.macKeyTag, kex)
var macKey []byte
if !aeadCiphers[algs.Cipher] {
macMode := macModes[algs.MAC]
macKey = make([]byte, macMode.keySize)
generateKeyMaterial(macKey, d.macKeyTag, kex)
}
return cipherModes[algs.Cipher].create(key, iv, macKey, algs)
}