chore: modernize CI and update Go toolchain

- Bump Go from 1.19 to 1.26 and update all dependencies
- Rewrite CI workflow with matrix strategy (Linux, macOS, Windows)
- Update GitHub Actions to current versions (checkout@v4, setup-go@v5)
- Update CodeQL actions from v1 to v3
- Fix cross-platform bug in mock/path.go (path.Join -> filepath.Join)
- Clean up dependabot config (weekly schedule, remove stale ignore)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
This commit is contained in:
Christopher Allen Lane
2026-02-14 20:58:51 -05:00
parent cc85a4bdb1
commit 2a19755804
657 changed files with 49050 additions and 32001 deletions

View File

@@ -10,7 +10,7 @@
// References:
//
// [PROTOCOL.agent]: https://tools.ietf.org/html/draft-miller-ssh-agent-00
package agent // import "golang.org/x/crypto/ssh/agent"
package agent
import (
"bytes"
@@ -430,8 +430,9 @@ func (c *client) List() ([]*Key, error) {
return keys, nil
case *failureAgentMsg:
return nil, errors.New("agent: failed to list keys")
default:
return nil, fmt.Errorf("agent: failed to list keys, unexpected message type %T", msg)
}
panic("unreachable")
}
// Sign has the agent sign the data using a protocol 2 key as defined
@@ -462,8 +463,9 @@ func (c *client) SignWithFlags(key ssh.PublicKey, data []byte, flags SignatureFl
return &sig, nil
case *failureAgentMsg:
return nil, errors.New("agent: failed to sign challenge")
default:
return nil, fmt.Errorf("agent: failed to sign challenge, unexpected message type %T", msg)
}
panic("unreachable")
}
// unmarshal parses an agent message in packet, returning the parsed
@@ -555,7 +557,7 @@ func (c *client) insertKey(s interface{}, comment string, constraints []byte) er
})
case *dsa.PrivateKey:
req = ssh.Marshal(dsaKeyMsg{
Type: ssh.KeyAlgoDSA,
Type: ssh.InsecureKeyAlgoDSA,
P: k.P,
Q: k.Q,
G: k.G,
@@ -803,16 +805,16 @@ var _ ssh.AlgorithmSigner = &agentKeyringSigner{}
//
// 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,
ssh.CertAlgoRSAv01: ssh.KeyAlgoRSA,
ssh.CertAlgoRSASHA256v01: ssh.KeyAlgoRSASHA256,
ssh.CertAlgoRSASHA512v01: ssh.KeyAlgoRSASHA512,
ssh.InsecureCertAlgoDSAv01: ssh.InsecureKeyAlgoDSA,
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

View File

@@ -112,7 +112,7 @@ 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
// with a lifetimesecs constraint and seconds >= lifetimesecs seconds have
// elapsed, it is removed. The caller *must* be holding the keyring mutex.
func (r *keyring) expireKeysLocked() {
for _, k := range r.keys {
@@ -175,6 +175,15 @@ func (r *keyring) Add(key AddedKey) error {
p.expire = &t
}
// If we already have a Signer with the same public key, replace it with the
// new one.
for idx, k := range r.keys {
if bytes.Equal(k.signer.PublicKey().Marshal(), p.signer.PublicKey().Marshal()) {
r.keys[idx] = p
return nil
}
}
r.keys = append(r.keys, p)
return nil

View File

@@ -203,6 +203,9 @@ func parseConstraints(constraints []byte) (lifetimeSecs uint32, confirmBeforeUse
for len(constraints) != 0 {
switch constraints[0] {
case agentConstrainLifetime:
if len(constraints) < 5 {
return 0, false, nil, io.ErrUnexpectedEOF
}
lifetimeSecs = binary.BigEndian.Uint32(constraints[1:5])
constraints = constraints[5:]
case agentConstrainConfirm:
@@ -506,7 +509,7 @@ func (s *server) insertIdentity(req []byte) error {
switch record.Type {
case ssh.KeyAlgoRSA:
addedKey, err = parseRSAKey(req)
case ssh.KeyAlgoDSA:
case ssh.InsecureKeyAlgoDSA:
addedKey, err = parseDSAKey(req)
case ssh.KeyAlgoECDSA256, ssh.KeyAlgoECDSA384, ssh.KeyAlgoECDSA521:
addedKey, err = parseECDSAKey(req)
@@ -514,7 +517,7 @@ func (s *server) insertIdentity(req []byte) error {
addedKey, err = parseEd25519Key(req)
case ssh.CertAlgoRSAv01:
addedKey, err = parseRSACert(req)
case ssh.CertAlgoDSAv01:
case ssh.InsecureCertAlgoDSAv01:
addedKey, err = parseDSACert(req)
case ssh.CertAlgoECDSA256v01, ssh.CertAlgoECDSA384v01, ssh.CertAlgoECDSA521v01:
addedKey, err = parseECDSACert(req)

View File

@@ -20,14 +20,19 @@ import (
// returned by MultiAlgorithmSigner and don't appear in the Signature.Format
// field.
const (
CertAlgoRSAv01 = "ssh-rsa-cert-v01@openssh.com"
CertAlgoDSAv01 = "ssh-dss-cert-v01@openssh.com"
CertAlgoECDSA256v01 = "ecdsa-sha2-nistp256-cert-v01@openssh.com"
CertAlgoECDSA384v01 = "ecdsa-sha2-nistp384-cert-v01@openssh.com"
CertAlgoECDSA521v01 = "ecdsa-sha2-nistp521-cert-v01@openssh.com"
CertAlgoSKECDSA256v01 = "sk-ecdsa-sha2-nistp256-cert-v01@openssh.com"
CertAlgoED25519v01 = "ssh-ed25519-cert-v01@openssh.com"
CertAlgoSKED25519v01 = "sk-ssh-ed25519-cert-v01@openssh.com"
CertAlgoRSAv01 = "ssh-rsa-cert-v01@openssh.com"
// Deprecated: DSA is only supported at insecure key sizes, and was removed
// from major implementations.
CertAlgoDSAv01 = InsecureCertAlgoDSAv01
// Deprecated: DSA is only supported at insecure key sizes, and was removed
// from major implementations.
InsecureCertAlgoDSAv01 = "ssh-dss-cert-v01@openssh.com"
CertAlgoECDSA256v01 = "ecdsa-sha2-nistp256-cert-v01@openssh.com"
CertAlgoECDSA384v01 = "ecdsa-sha2-nistp384-cert-v01@openssh.com"
CertAlgoECDSA521v01 = "ecdsa-sha2-nistp521-cert-v01@openssh.com"
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
@@ -228,7 +233,11 @@ func parseCert(in []byte, privAlgo string) (*Certificate, error) {
if err != nil {
return nil, err
}
// The Type() function is intended to return only certificate key types, but
// we use certKeyAlgoNames anyway for safety, to match [Certificate.Type].
if _, ok := certKeyAlgoNames[k.Type()]; ok {
return nil, fmt.Errorf("ssh: the signature key type %q is invalid for certificates", k.Type())
}
c.SignatureKey = k
c.Signature, rest, ok = parseSignatureBody(g.Signature)
if !ok || len(rest) > 0 {
@@ -296,16 +305,13 @@ type CertChecker struct {
SupportedCriticalOptions []string
// IsUserAuthority should return true if the key is recognized as an
// authority for the given user certificate. This allows for
// certificates to be signed by other certificates. This must be set
// if this CertChecker will be checking user certificates.
// authority for user certificate. This must be set if this CertChecker
// will be checking user certificates.
IsUserAuthority func(auth PublicKey) bool
// IsHostAuthority should report whether the key is recognized as
// an authority for this host. This allows for certificates to be
// signed by other keys, and for those other keys to only be valid
// signers for particular hostnames. This must be set if this
// CertChecker will be checking host certificates.
// an authority for this host. This must be set if this CertChecker
// will be checking host certificates.
IsHostAuthority func(auth PublicKey, address string) bool
// Clock is used for verifying time stamps. If nil, time.Now
@@ -442,12 +448,19 @@ func (c *CertChecker) CheckCert(principal string, cert *Certificate) error {
// SignCert signs the certificate with an authority, setting the Nonce,
// SignatureKey, and Signature fields. If the authority implements the
// MultiAlgorithmSigner interface the first algorithm in the list is used. This
// is useful if you want to sign with a specific algorithm.
// is useful if you want to sign with a specific algorithm. As specified in
// [SSH-CERTS], Section 2.1.1, authority can't be a [Certificate].
func (c *Certificate) SignCert(rand io.Reader, authority Signer) error {
c.Nonce = make([]byte, 32)
if _, err := io.ReadFull(rand, c.Nonce); err != nil {
return err
}
// The Type() function is intended to return only certificate key types, but
// we use certKeyAlgoNames anyway for safety, to match [Certificate.Type].
if _, ok := certKeyAlgoNames[authority.PublicKey().Type()]; ok {
return fmt.Errorf("ssh: certificates cannot be used as authority (public key type %q)",
authority.PublicKey().Type())
}
c.SignatureKey = authority.PublicKey()
if v, ok := authority.(MultiAlgorithmSigner); ok {
@@ -485,16 +498,16 @@ func (c *Certificate) SignCert(rand io.Reader, authority Signer) error {
//
// 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,
CertAlgoRSAv01: KeyAlgoRSA,
CertAlgoRSASHA256v01: KeyAlgoRSASHA256,
CertAlgoRSASHA512v01: KeyAlgoRSASHA512,
InsecureCertAlgoDSAv01: InsecureKeyAlgoDSA,
CertAlgoECDSA256v01: KeyAlgoECDSA256,
CertAlgoECDSA384v01: KeyAlgoECDSA384,
CertAlgoECDSA521v01: KeyAlgoECDSA521,
CertAlgoSKECDSA256v01: KeyAlgoSKECDSA256,
CertAlgoED25519v01: KeyAlgoED25519,
CertAlgoSKED25519v01: KeyAlgoSKED25519,
}
// underlyingAlgo returns the signature algorithm associated with algo (which is

View File

@@ -8,6 +8,7 @@ import (
"crypto/aes"
"crypto/cipher"
"crypto/des"
"crypto/fips140"
"crypto/rc4"
"crypto/subtle"
"encoding/binary"
@@ -15,6 +16,7 @@ import (
"fmt"
"hash"
"io"
"slices"
"golang.org/x/crypto/chacha20"
"golang.org/x/crypto/internal/poly1305"
@@ -58,11 +60,11 @@ func newRC4(key, iv []byte) (cipher.Stream, error) {
type cipherMode struct {
keySize int
ivSize int
create func(key, iv []byte, macKey []byte, algs directionAlgorithms) (packetCipher, error)
create func(key, iv []byte, macKey []byte, algs DirectionAlgorithms) (packetCipher, error)
}
func streamCipherMode(skip int, createFunc func(key, iv []byte) (cipher.Stream, error)) func(key, iv []byte, macKey []byte, algs directionAlgorithms) (packetCipher, error) {
return func(key, iv, macKey []byte, algs directionAlgorithms) (packetCipher, error) {
func streamCipherMode(skip int, createFunc func(key, iv []byte) (cipher.Stream, error)) func(key, iv []byte, macKey []byte, algs DirectionAlgorithms) (packetCipher, error) {
return func(key, iv, macKey []byte, algs DirectionAlgorithms) (packetCipher, error) {
stream, err := createFunc(key, iv)
if err != nil {
return nil, err
@@ -93,41 +95,41 @@ func streamCipherMode(skip int, createFunc func(key, iv []byte) (cipher.Stream,
}
// cipherModes documents properties of supported ciphers. Ciphers not included
// are not supported and will not be negotiated, even if explicitly requested in
// ClientConfig.Crypto.Ciphers.
var cipherModes = map[string]*cipherMode{
// 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)},
// are not supported and will not be negotiated, even if explicitly configured.
// When FIPS mode is enabled, only FIPS-approved algorithms are included.
var cipherModes = map[string]*cipherMode{}
// 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)},
func init() {
cipherModes[CipherAES128CTR] = &cipherMode{16, aes.BlockSize, streamCipherMode(0, newAESCTR)}
cipherModes[CipherAES192CTR] = &cipherMode{24, aes.BlockSize, streamCipherMode(0, newAESCTR)}
cipherModes[CipherAES256CTR] = &cipherMode{32, aes.BlockSize, streamCipherMode(0, newAESCTR)}
// Use of GCM with arbitrary IVs is not allowed in FIPS 140-only mode,
// we'll wire it up to NewGCMForSSH in Go 1.26.
//
// For now it means we'll work with fips140=on but not fips140=only.
cipherModes[CipherAES128GCM] = &cipherMode{16, 12, newGCMCipher}
cipherModes[CipherAES256GCM] = &cipherMode{32, 12, newGCMCipher}
// 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."
// RFC 4345 introduces improved versions of Arcfour.
"arcfour": {16, 0, streamCipherMode(0, newRC4)},
// AEAD ciphers
gcm128CipherID: {16, 12, newGCMCipher},
gcm256CipherID: {32, 12, newGCMCipher},
chacha20Poly1305ID: {64, 0, newChaCha20Cipher},
if fips140.Enabled() {
defaultCiphers = slices.DeleteFunc(defaultCiphers, func(algo string) bool {
_, ok := cipherModes[algo]
return !ok
})
return
}
cipherModes[CipherChaCha20Poly1305] = &cipherMode{64, 0, newChaCha20Cipher}
// Insecure ciphers not included in the default configuration.
cipherModes[InsecureCipherRC4128] = &cipherMode{16, 0, streamCipherMode(1536, newRC4)}
cipherModes[InsecureCipherRC4256] = &cipherMode{32, 0, streamCipherMode(1536, newRC4)}
cipherModes[InsecureCipherRC4] = &cipherMode{16, 0, streamCipherMode(0, newRC4)}
// CBC mode is insecure and so is not included in the default config.
// (See https://www.ieee-security.org/TC/SP2013/papers/4977a526.pdf). If absolutely
// needed, it's possible to specify a custom Config to enable it.
// You should expect that an active attacker can recover plaintext if
// you do.
aes128cbcID: {16, aes.BlockSize, newAESCBCCipher},
// 3des-cbc is insecure and is not included in the default
// config.
tripledescbcID: {24, des.BlockSize, newTripleDESCBCCipher},
cipherModes[InsecureCipherAES128CBC] = &cipherMode{16, aes.BlockSize, newAESCBCCipher}
cipherModes[InsecureCipherTripleDESCBC] = &cipherMode{24, des.BlockSize, newTripleDESCBCCipher}
}
// prefixLen is the length of the packet prefix that contains the packet length
@@ -307,7 +309,7 @@ type gcmCipher struct {
buf []byte
}
func newGCMCipher(key, iv, unusedMacKey []byte, unusedAlgs directionAlgorithms) (packetCipher, error) {
func newGCMCipher(key, iv, unusedMacKey []byte, unusedAlgs DirectionAlgorithms) (packetCipher, error) {
c, err := aes.NewCipher(key)
if err != nil {
return nil, err
@@ -429,7 +431,7 @@ type cbcCipher struct {
oracleCamouflage uint32
}
func newCBCCipher(c cipher.Block, key, iv, macKey []byte, algs directionAlgorithms) (packetCipher, error) {
func newCBCCipher(c cipher.Block, key, iv, macKey []byte, algs DirectionAlgorithms) (packetCipher, error) {
cbc := &cbcCipher{
mac: macModes[algs.MAC].new(macKey),
decrypter: cipher.NewCBCDecrypter(c, iv),
@@ -443,7 +445,7 @@ func newCBCCipher(c cipher.Block, key, iv, macKey []byte, algs directionAlgorith
return cbc, nil
}
func newAESCBCCipher(key, iv, macKey []byte, algs directionAlgorithms) (packetCipher, error) {
func newAESCBCCipher(key, iv, macKey []byte, algs DirectionAlgorithms) (packetCipher, error) {
c, err := aes.NewCipher(key)
if err != nil {
return nil, err
@@ -457,7 +459,7 @@ func newAESCBCCipher(key, iv, macKey []byte, algs directionAlgorithms) (packetCi
return cbc, nil
}
func newTripleDESCBCCipher(key, iv, macKey []byte, algs directionAlgorithms) (packetCipher, error) {
func newTripleDESCBCCipher(key, iv, macKey []byte, algs DirectionAlgorithms) (packetCipher, error) {
c, err := des.NewTripleDESCipher(key)
if err != nil {
return nil, err
@@ -635,8 +637,6 @@ func (c *cbcCipher) writeCipherPacket(seqNum uint32, w io.Writer, rand io.Reader
return nil
}
const chacha20Poly1305ID = "chacha20-poly1305@openssh.com"
// chacha20Poly1305Cipher implements the chacha20-poly1305@openssh.com
// AEAD, which is described here:
//
@@ -650,7 +650,7 @@ type chacha20Poly1305Cipher struct {
buf []byte
}
func newChaCha20Cipher(key, unusedIV, unusedMACKey []byte, unusedAlgs directionAlgorithms) (packetCipher, error) {
func newChaCha20Cipher(key, unusedIV, unusedMACKey []byte, unusedAlgs DirectionAlgorithms) (packetCipher, error) {
if len(key) != 64 {
panic(len(key))
}

View File

@@ -110,6 +110,7 @@ func (c *connection) clientHandshake(dialAddress string, config *ClientConfig) e
}
c.sessionID = c.transport.getSessionID()
c.algorithms = c.transport.getAlgorithms()
return c.clientAuthenticate(config)
}

View File

@@ -9,6 +9,7 @@ import (
"errors"
"fmt"
"io"
"slices"
"strings"
)
@@ -71,6 +72,10 @@ func (c *connection) clientAuthenticate(config *ClientConfig) error {
for auth := AuthMethod(new(noneAuth)); auth != nil; {
ok, methods, err := auth.auth(sessionID, config.User, c.transport, config.Rand, extensions)
if err != nil {
// On disconnect, return error immediately
if _, ok := err.(*disconnectMsg); ok {
return err
}
// We return the error later if there is no other method left to
// try.
ok = authFailure
@@ -79,7 +84,7 @@ func (c *connection) clientAuthenticate(config *ClientConfig) error {
// success
return nil
} else if ok == authFailure {
if m := auth.method(); !contains(tried, m) {
if m := auth.method(); !slices.Contains(tried, m) {
tried = append(tried, m)
}
}
@@ -93,7 +98,7 @@ func (c *connection) clientAuthenticate(config *ClientConfig) error {
findNext:
for _, a := range config.Auth {
candidateMethod := a.method()
if contains(tried, candidateMethod) {
if slices.Contains(tried, candidateMethod) {
continue
}
for _, meth := range methods {
@@ -113,15 +118,6 @@ func (c *connection) clientAuthenticate(config *ClientConfig) error {
return fmt.Errorf("ssh: unable to authenticate, attempted methods %v, no supported methods remain", tried)
}
func contains(list []string, e string) bool {
for _, s := range list {
if s == e {
return true
}
}
return false
}
// An AuthMethod represents an instance of an RFC 4252 authentication method.
type AuthMethod interface {
// auth authenticates user over transport t.
@@ -251,7 +247,7 @@ func pickSignatureAlgorithm(signer Signer, extensions map[string][]byte) (MultiA
// Fallback to use if there is no "server-sig-algs" extension or a
// common algorithm cannot be found. We use the public key format if the
// MultiAlgorithmSigner supports it, otherwise we return an error.
if !contains(as.Algorithms(), underlyingAlgo(keyFormat)) {
if !slices.Contains(as.Algorithms(), underlyingAlgo(keyFormat)) {
return "", fmt.Errorf("ssh: no common public key signature algorithm, server only supports %q for key type %q, signer only supports %v",
underlyingAlgo(keyFormat), keyFormat, as.Algorithms())
}
@@ -280,12 +276,12 @@ func pickSignatureAlgorithm(signer Signer, extensions map[string][]byte) (MultiA
// Filter algorithms based on those supported by MultiAlgorithmSigner.
var keyAlgos []string
for _, algo := range algorithmsForKeyFormat(keyFormat) {
if contains(as.Algorithms(), underlyingAlgo(algo)) {
if slices.Contains(as.Algorithms(), underlyingAlgo(algo)) {
keyAlgos = append(keyAlgos, algo)
}
}
algo, err := findCommon("public key signature algorithm", keyAlgos, serverAlgos)
algo, err := findCommon("public key signature algorithm", keyAlgos, serverAlgos, true)
if err != nil {
// If there is no overlap, return the fallback algorithm to support
// servers that fail to list all supported algorithms.
@@ -330,7 +326,7 @@ func (cb publicKeyCallback) auth(session []byte, user string, c packetConn, rand
// the key try to use the obtained algorithm as if "server-sig-algs" had
// not been implemented if supported from the algorithm signer.
if !ok && idx < origSignersLen && isRSACert(algo) && algo != CertAlgoRSAv01 {
if contains(as.Algorithms(), KeyAlgoRSA) {
if slices.Contains(as.Algorithms(), KeyAlgoRSA) {
// We retry using the compat algorithm after all signers have
// been tried normally.
signers = append(signers, &multiAlgorithmSigner{
@@ -381,7 +377,7 @@ func (cb publicKeyCallback) auth(session []byte, user string, c packetConn, rand
// contain the "publickey" method, do not attempt to authenticate with any
// other keys. According to RFC 4252 Section 7, the latter can occur when
// additional authentication methods are required.
if success == authSuccess || !contains(methods, cb.method()) {
if success == authSuccess || !slices.Contains(methods, cb.method()) {
return success, methods, err
}
}
@@ -404,10 +400,10 @@ func validateKey(key PublicKey, algo string, user string, c packetConn) (bool, e
return false, err
}
return confirmKeyAck(key, algo, c)
return confirmKeyAck(key, c)
}
func confirmKeyAck(key PublicKey, algo string, c packetConn) (bool, error) {
func confirmKeyAck(key PublicKey, c packetConn) (bool, error) {
pubKey := key.Marshal()
for {
@@ -425,7 +421,15 @@ func confirmKeyAck(key PublicKey, algo string, c packetConn) (bool, error) {
if err := Unmarshal(packet, &msg); err != nil {
return false, err
}
if msg.Algo != algo || !bytes.Equal(msg.PubKey, pubKey) {
// According to RFC 4252 Section 7 the algorithm in
// SSH_MSG_USERAUTH_PK_OK should match that of the request but some
// servers send the key type instead. OpenSSH allows any algorithm
// that matches the public key, so we do the same.
// https://github.com/openssh/openssh-portable/blob/86bdd385/sshconnect2.c#L709
if !slices.Contains(algorithmsForKeyFormat(key.Type()), msg.Algo) {
return false, nil
}
if !bytes.Equal(msg.PubKey, pubKey) {
return false, nil
}
return true, nil
@@ -543,6 +547,7 @@ func (cb KeyboardInteractiveChallenge) auth(session []byte, user string, c packe
}
gotMsgExtInfo := false
gotUserAuthInfoRequest := false
for {
packet, err := c.readPacket()
if err != nil {
@@ -573,6 +578,9 @@ func (cb KeyboardInteractiveChallenge) auth(session []byte, user string, c packe
if msg.PartialSuccess {
return authPartialSuccess, msg.Methods, nil
}
if !gotUserAuthInfoRequest {
return authFailure, msg.Methods, unexpectedMessageError(msgUserAuthInfoRequest, packet[0])
}
return authFailure, msg.Methods, nil
case msgUserAuthSuccess:
return authSuccess, nil, nil
@@ -584,6 +592,7 @@ func (cb KeyboardInteractiveChallenge) auth(session []byte, user string, c packe
if err := Unmarshal(packet, &msg); err != nil {
return authFailure, nil, err
}
gotUserAuthInfoRequest = true
// Manually unpack the prompt/echo pairs.
rest := msg.Prompts

View File

@@ -6,10 +6,12 @@ package ssh
import (
"crypto"
"crypto/fips140"
"crypto/rand"
"fmt"
"io"
"math"
"slices"
"sync"
_ "crypto/sha1"
@@ -24,88 +26,298 @@ const (
serviceSSH = "ssh-connection"
)
// supportedCiphers lists ciphers we support but might not recommend.
var supportedCiphers = []string{
"aes128-ctr", "aes192-ctr", "aes256-ctr",
"aes128-gcm@openssh.com", gcm256CipherID,
chacha20Poly1305ID,
"arcfour256", "arcfour128", "arcfour",
aes128cbcID,
tripledescbcID,
// The ciphers currently or previously implemented by this library, to use in
// [Config.Ciphers]. For a list, see the [Algorithms.Ciphers] returned by
// [SupportedAlgorithms] or [InsecureAlgorithms].
const (
CipherAES128GCM = "aes128-gcm@openssh.com"
CipherAES256GCM = "aes256-gcm@openssh.com"
CipherChaCha20Poly1305 = "chacha20-poly1305@openssh.com"
CipherAES128CTR = "aes128-ctr"
CipherAES192CTR = "aes192-ctr"
CipherAES256CTR = "aes256-ctr"
InsecureCipherAES128CBC = "aes128-cbc"
InsecureCipherTripleDESCBC = "3des-cbc"
InsecureCipherRC4 = "arcfour"
InsecureCipherRC4128 = "arcfour128"
InsecureCipherRC4256 = "arcfour256"
)
// The key exchanges currently or previously implemented by this library, to use
// in [Config.KeyExchanges]. For a list, see the
// [Algorithms.KeyExchanges] returned by [SupportedAlgorithms] or
// [InsecureAlgorithms].
const (
InsecureKeyExchangeDH1SHA1 = "diffie-hellman-group1-sha1"
InsecureKeyExchangeDH14SHA1 = "diffie-hellman-group14-sha1"
KeyExchangeDH14SHA256 = "diffie-hellman-group14-sha256"
KeyExchangeDH16SHA512 = "diffie-hellman-group16-sha512"
KeyExchangeECDHP256 = "ecdh-sha2-nistp256"
KeyExchangeECDHP384 = "ecdh-sha2-nistp384"
KeyExchangeECDHP521 = "ecdh-sha2-nistp521"
KeyExchangeCurve25519 = "curve25519-sha256"
InsecureKeyExchangeDHGEXSHA1 = "diffie-hellman-group-exchange-sha1"
KeyExchangeDHGEXSHA256 = "diffie-hellman-group-exchange-sha256"
// KeyExchangeMLKEM768X25519 is supported from Go 1.24.
KeyExchangeMLKEM768X25519 = "mlkem768x25519-sha256"
// An alias for KeyExchangeCurve25519SHA256. This kex ID will be added if
// KeyExchangeCurve25519SHA256 is requested for backward compatibility with
// OpenSSH versions up to 7.2.
keyExchangeCurve25519LibSSH = "curve25519-sha256@libssh.org"
)
// The message authentication code (MAC) currently or previously implemented by
// this library, to use in [Config.MACs]. For a list, see the
// [Algorithms.MACs] returned by [SupportedAlgorithms] or
// [InsecureAlgorithms].
const (
HMACSHA256ETM = "hmac-sha2-256-etm@openssh.com"
HMACSHA512ETM = "hmac-sha2-512-etm@openssh.com"
HMACSHA256 = "hmac-sha2-256"
HMACSHA512 = "hmac-sha2-512"
HMACSHA1 = "hmac-sha1"
InsecureHMACSHA196 = "hmac-sha1-96"
)
var (
// supportedKexAlgos specifies key-exchange algorithms implemented by this
// package in preference order, excluding those with security issues.
supportedKexAlgos = []string{
KeyExchangeMLKEM768X25519,
KeyExchangeCurve25519,
KeyExchangeECDHP256,
KeyExchangeECDHP384,
KeyExchangeECDHP521,
KeyExchangeDH14SHA256,
KeyExchangeDH16SHA512,
KeyExchangeDHGEXSHA256,
}
// defaultKexAlgos specifies the default preference for key-exchange
// algorithms in preference order.
defaultKexAlgos = []string{
KeyExchangeMLKEM768X25519,
KeyExchangeCurve25519,
KeyExchangeECDHP256,
KeyExchangeECDHP384,
KeyExchangeECDHP521,
KeyExchangeDH14SHA256,
InsecureKeyExchangeDH14SHA1,
}
// insecureKexAlgos specifies key-exchange algorithms implemented by this
// package and which have security issues.
insecureKexAlgos = []string{
InsecureKeyExchangeDH14SHA1,
InsecureKeyExchangeDH1SHA1,
InsecureKeyExchangeDHGEXSHA1,
}
// supportedCiphers specifies cipher algorithms implemented by this package
// in preference order, excluding those with security issues.
supportedCiphers = []string{
CipherAES128GCM,
CipherAES256GCM,
CipherChaCha20Poly1305,
CipherAES128CTR,
CipherAES192CTR,
CipherAES256CTR,
}
// defaultCiphers specifies the default preference for ciphers algorithms
// in preference order.
defaultCiphers = supportedCiphers
// insecureCiphers specifies cipher algorithms implemented by this
// package and which have security issues.
insecureCiphers = []string{
InsecureCipherAES128CBC,
InsecureCipherTripleDESCBC,
InsecureCipherRC4256,
InsecureCipherRC4128,
InsecureCipherRC4,
}
// supportedMACs specifies MAC algorithms implemented by this package in
// preference order, excluding those with security issues.
supportedMACs = []string{
HMACSHA256ETM,
HMACSHA512ETM,
HMACSHA256,
HMACSHA512,
HMACSHA1,
}
// defaultMACs specifies the default preference for MAC algorithms in
// preference order.
defaultMACs = []string{
HMACSHA256ETM,
HMACSHA512ETM,
HMACSHA256,
HMACSHA512,
HMACSHA1,
InsecureHMACSHA196,
}
// insecureMACs specifies MAC algorithms implemented by this
// package and which have security issues.
insecureMACs = []string{
InsecureHMACSHA196,
}
// supportedHostKeyAlgos specifies the supported host-key algorithms (i.e.
// methods of authenticating servers) implemented by this package in
// preference order, excluding those with security issues.
supportedHostKeyAlgos = []string{
CertAlgoRSASHA256v01,
CertAlgoRSASHA512v01,
CertAlgoECDSA256v01,
CertAlgoECDSA384v01,
CertAlgoECDSA521v01,
CertAlgoED25519v01,
KeyAlgoRSASHA256,
KeyAlgoRSASHA512,
KeyAlgoECDSA256,
KeyAlgoECDSA384,
KeyAlgoECDSA521,
KeyAlgoED25519,
}
// defaultHostKeyAlgos specifies the default preference for host-key
// algorithms in preference order.
defaultHostKeyAlgos = []string{
CertAlgoRSASHA256v01,
CertAlgoRSASHA512v01,
CertAlgoRSAv01,
InsecureCertAlgoDSAv01,
CertAlgoECDSA256v01,
CertAlgoECDSA384v01,
CertAlgoECDSA521v01,
CertAlgoED25519v01,
KeyAlgoECDSA256,
KeyAlgoECDSA384,
KeyAlgoECDSA521,
KeyAlgoRSASHA256,
KeyAlgoRSASHA512,
KeyAlgoRSA,
InsecureKeyAlgoDSA,
KeyAlgoED25519,
}
// insecureHostKeyAlgos specifies host-key algorithms implemented by this
// package and which have security issues.
insecureHostKeyAlgos = []string{
KeyAlgoRSA,
InsecureKeyAlgoDSA,
CertAlgoRSAv01,
InsecureCertAlgoDSAv01,
}
// supportedPubKeyAuthAlgos specifies the supported client public key
// authentication algorithms. Note that this doesn't include certificate
// types since those use the underlying algorithm. Order is irrelevant.
supportedPubKeyAuthAlgos = []string{
KeyAlgoED25519,
KeyAlgoSKED25519,
KeyAlgoSKECDSA256,
KeyAlgoECDSA256,
KeyAlgoECDSA384,
KeyAlgoECDSA521,
KeyAlgoRSASHA256,
KeyAlgoRSASHA512,
}
// defaultPubKeyAuthAlgos specifies the preferred client public key
// authentication algorithms. This list is sent to the client if it supports
// the server-sig-algs extension. Order is irrelevant.
defaultPubKeyAuthAlgos = []string{
KeyAlgoED25519,
KeyAlgoSKED25519,
KeyAlgoSKECDSA256,
KeyAlgoECDSA256,
KeyAlgoECDSA384,
KeyAlgoECDSA521,
KeyAlgoRSASHA256,
KeyAlgoRSASHA512,
KeyAlgoRSA,
InsecureKeyAlgoDSA,
}
// insecurePubKeyAuthAlgos specifies client public key authentication
// algorithms implemented by this package and which have security issues.
insecurePubKeyAuthAlgos = []string{
KeyAlgoRSA,
InsecureKeyAlgoDSA,
}
)
// NegotiatedAlgorithms defines algorithms negotiated between client and server.
type NegotiatedAlgorithms struct {
KeyExchange string
HostKey string
Read DirectionAlgorithms
Write DirectionAlgorithms
}
// preferredCiphers specifies the default preference for ciphers.
var preferredCiphers = []string{
"aes128-gcm@openssh.com", gcm256CipherID,
chacha20Poly1305ID,
"aes128-ctr", "aes192-ctr", "aes256-ctr",
// Algorithms defines a set of algorithms that can be configured in the client
// or server config for negotiation during a handshake.
type Algorithms struct {
KeyExchanges []string
Ciphers []string
MACs []string
HostKeys []string
PublicKeyAuths []string
}
// supportedKexAlgos specifies the supported key-exchange algorithms in
// preference order.
var supportedKexAlgos = []string{
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,
kexAlgoDH14SHA256, kexAlgoDH16SHA512, kexAlgoDH14SHA1,
kexAlgoDH1SHA1,
func init() {
if fips140.Enabled() {
defaultHostKeyAlgos = slices.DeleteFunc(defaultHostKeyAlgos, func(algo string) bool {
_, err := hashFunc(underlyingAlgo(algo))
return err != nil
})
defaultPubKeyAuthAlgos = slices.DeleteFunc(defaultPubKeyAuthAlgos, func(algo string) bool {
_, err := hashFunc(underlyingAlgo(algo))
return err != nil
})
}
}
// serverForbiddenKexAlgos contains key exchange algorithms, that are forbidden
// for the server half.
var serverForbiddenKexAlgos = map[string]struct{}{
kexAlgoDHGEXSHA1: {}, // server half implementation is only minimal to satisfy the automated tests
kexAlgoDHGEXSHA256: {}, // server half implementation is only minimal to satisfy the automated tests
func hashFunc(format string) (crypto.Hash, error) {
switch format {
case KeyAlgoRSASHA256, KeyAlgoECDSA256, KeyAlgoSKED25519, KeyAlgoSKECDSA256:
return crypto.SHA256, nil
case KeyAlgoECDSA384:
return crypto.SHA384, nil
case KeyAlgoRSASHA512, KeyAlgoECDSA521:
return crypto.SHA512, nil
case KeyAlgoED25519:
// KeyAlgoED25519 doesn't pre-hash.
return 0, nil
case KeyAlgoRSA, InsecureKeyAlgoDSA:
if fips140.Enabled() {
return 0, fmt.Errorf("ssh: hash algorithm for format %q not allowed in FIPS 140 mode", format)
}
return crypto.SHA1, nil
default:
return 0, fmt.Errorf("ssh: hash algorithm for format %q not mapped", format)
}
}
// preferredKexAlgos specifies the default preference for key-exchange
// algorithms in preference order. The diffie-hellman-group16-sha512 algorithm
// is disabled by default because it is a bit slower than the others.
var preferredKexAlgos = []string{
kexAlgoCurve25519SHA256, kexAlgoCurve25519SHA256LibSSH,
kexAlgoECDH256, kexAlgoECDH384, kexAlgoECDH521,
kexAlgoDH14SHA256, kexAlgoDH14SHA1,
// SupportedAlgorithms returns algorithms currently implemented by this package,
// excluding those with security issues, which are returned by
// InsecureAlgorithms. The algorithms listed here are in preference order.
func SupportedAlgorithms() Algorithms {
return Algorithms{
Ciphers: slices.Clone(supportedCiphers),
MACs: slices.Clone(supportedMACs),
KeyExchanges: slices.Clone(supportedKexAlgos),
HostKeys: slices.Clone(supportedHostKeyAlgos),
PublicKeyAuths: slices.Clone(supportedPubKeyAuthAlgos),
}
}
// supportedHostKeyAlgos specifies the supported host-key algorithms (i.e. methods
// of authenticating servers) in preference order.
var supportedHostKeyAlgos = []string{
CertAlgoRSASHA256v01, CertAlgoRSASHA512v01,
CertAlgoRSAv01, CertAlgoDSAv01, CertAlgoECDSA256v01,
CertAlgoECDSA384v01, CertAlgoECDSA521v01, CertAlgoED25519v01,
KeyAlgoECDSA256, KeyAlgoECDSA384, KeyAlgoECDSA521,
KeyAlgoRSASHA256, KeyAlgoRSASHA512,
KeyAlgoRSA, KeyAlgoDSA,
KeyAlgoED25519,
}
// supportedMACs specifies a default set of MAC algorithms in preference order.
// This is based on RFC 4253, section 6.4, but with hmac-md5 variants removed
// because they have reached the end of their useful life.
var supportedMACs = []string{
"hmac-sha2-256-etm@openssh.com", "hmac-sha2-512-etm@openssh.com", "hmac-sha2-256", "hmac-sha2-512", "hmac-sha1", "hmac-sha1-96",
// InsecureAlgorithms returns algorithms currently implemented by this package
// and which have security issues.
func InsecureAlgorithms() Algorithms {
return Algorithms{
KeyExchanges: slices.Clone(insecureKexAlgos),
Ciphers: slices.Clone(insecureCiphers),
MACs: slices.Clone(insecureMACs),
HostKeys: slices.Clone(insecureHostKeyAlgos),
PublicKeyAuths: slices.Clone(insecurePubKeyAuthAlgos),
}
}
var supportedCompressions = []string{compressionNone}
// 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,
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.
@@ -120,11 +332,40 @@ func algorithmsForKeyFormat(keyFormat string) []string {
}
}
// keyFormatForAlgorithm returns the key format corresponding to the given
// signature algorithm. It returns an empty string if the signature algorithm is
// invalid or unsupported.
func keyFormatForAlgorithm(sigAlgo string) string {
switch sigAlgo {
case KeyAlgoRSA, KeyAlgoRSASHA256, KeyAlgoRSASHA512:
return KeyAlgoRSA
case CertAlgoRSAv01, CertAlgoRSASHA256v01, CertAlgoRSASHA512v01:
return CertAlgoRSAv01
case KeyAlgoED25519,
KeyAlgoSKED25519,
KeyAlgoSKECDSA256,
KeyAlgoECDSA256,
KeyAlgoECDSA384,
KeyAlgoECDSA521,
InsecureKeyAlgoDSA,
InsecureCertAlgoDSAv01,
CertAlgoECDSA256v01,
CertAlgoECDSA384v01,
CertAlgoECDSA521v01,
CertAlgoSKECDSA256v01,
CertAlgoED25519v01,
CertAlgoSKED25519v01:
return sigAlgo
default:
return ""
}
}
// isRSA returns whether algo is a supported RSA algorithm, including certificate
// algorithms.
func isRSA(algo string) bool {
algos := algorithmsForKeyFormat(KeyAlgoRSA)
return contains(algos, underlyingAlgo(algo))
return slices.Contains(algos, underlyingAlgo(algo))
}
func isRSACert(algo string) bool {
@@ -135,18 +376,6 @@ func isRSACert(algo string) bool {
return isRSA(algo)
}
// 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,
}
// unexpectedMessageError results when the SSH message that we received didn't
// match what we wanted.
func unexpectedMessageError(expected, got uint8) error {
@@ -158,7 +387,7 @@ func parseError(tag uint8) error {
return fmt.Errorf("ssh: parse error in message type %d", tag)
}
func findCommon(what string, client []string, server []string) (common string, err error) {
func findCommon(what string, client []string, server []string, isClient bool) (string, error) {
for _, c := range client {
for _, s := range server {
if c == s {
@@ -166,23 +395,49 @@ func findCommon(what string, client []string, server []string) (common string, e
}
}
}
return "", fmt.Errorf("ssh: no common algorithm for %s; client offered: %v, server offered: %v", what, client, server)
err := &AlgorithmNegotiationError{
What: what,
}
if isClient {
err.SupportedAlgorithms = client
err.RequestedAlgorithms = server
} else {
err.SupportedAlgorithms = server
err.RequestedAlgorithms = client
}
return "", err
}
// directionAlgorithms records algorithm choices in one direction (either read or write)
type directionAlgorithms struct {
// AlgorithmNegotiationError defines the error returned if the client and the
// server cannot agree on an algorithm for key exchange, host key, cipher, MAC.
type AlgorithmNegotiationError struct {
What string
// RequestedAlgorithms lists the algorithms supported by the peer.
RequestedAlgorithms []string
// SupportedAlgorithms lists the algorithms supported on our side.
SupportedAlgorithms []string
}
func (a *AlgorithmNegotiationError) Error() string {
return fmt.Sprintf("ssh: no common algorithm for %s; we offered: %v, peer offered: %v",
a.What, a.SupportedAlgorithms, a.RequestedAlgorithms)
}
// DirectionAlgorithms defines the algorithms negotiated in one direction
// (either read or write).
type DirectionAlgorithms struct {
Cipher string
MAC string
Compression string
compression string
}
// rekeyBytes returns a rekeying intervals in bytes.
func (a *directionAlgorithms) rekeyBytes() int64 {
func (a *DirectionAlgorithms) rekeyBytes() int64 {
// According to RFC 4344 block ciphers should rekey after
// 2^(BLOCKSIZE/4) blocks. For all AES flavors BLOCKSIZE is
// 128.
switch a.Cipher {
case "aes128-ctr", "aes192-ctr", "aes256-ctr", gcm128CipherID, gcm256CipherID, aes128cbcID:
case CipherAES128CTR, CipherAES192CTR, CipherAES256CTR, CipherAES128GCM, CipherAES256GCM, InsecureCipherAES128CBC:
return 16 * (1 << 32)
}
@@ -192,66 +447,59 @@ func (a *directionAlgorithms) rekeyBytes() int64 {
}
var aeadCiphers = map[string]bool{
gcm128CipherID: true,
gcm256CipherID: true,
chacha20Poly1305ID: true,
CipherAES128GCM: true,
CipherAES256GCM: true,
CipherChaCha20Poly1305: true,
}
type algorithms struct {
kex string
hostKey string
w directionAlgorithms
r directionAlgorithms
}
func findAgreedAlgorithms(isClient bool, clientKexInit, serverKexInit *kexInitMsg) (algs *NegotiatedAlgorithms, err error) {
result := &NegotiatedAlgorithms{}
func findAgreedAlgorithms(isClient bool, clientKexInit, serverKexInit *kexInitMsg) (algs *algorithms, err error) {
result := &algorithms{}
result.kex, err = findCommon("key exchange", clientKexInit.KexAlgos, serverKexInit.KexAlgos)
result.KeyExchange, err = findCommon("key exchange", clientKexInit.KexAlgos, serverKexInit.KexAlgos, isClient)
if err != nil {
return
}
result.hostKey, err = findCommon("host key", clientKexInit.ServerHostKeyAlgos, serverKexInit.ServerHostKeyAlgos)
result.HostKey, err = findCommon("host key", clientKexInit.ServerHostKeyAlgos, serverKexInit.ServerHostKeyAlgos, isClient)
if err != nil {
return
}
stoc, ctos := &result.w, &result.r
stoc, ctos := &result.Write, &result.Read
if isClient {
ctos, stoc = stoc, ctos
}
ctos.Cipher, err = findCommon("client to server cipher", clientKexInit.CiphersClientServer, serverKexInit.CiphersClientServer)
ctos.Cipher, err = findCommon("client to server cipher", clientKexInit.CiphersClientServer, serverKexInit.CiphersClientServer, isClient)
if err != nil {
return
}
stoc.Cipher, err = findCommon("server to client cipher", clientKexInit.CiphersServerClient, serverKexInit.CiphersServerClient)
stoc.Cipher, err = findCommon("server to client cipher", clientKexInit.CiphersServerClient, serverKexInit.CiphersServerClient, isClient)
if err != nil {
return
}
if !aeadCiphers[ctos.Cipher] {
ctos.MAC, err = findCommon("client to server MAC", clientKexInit.MACsClientServer, serverKexInit.MACsClientServer)
ctos.MAC, err = findCommon("client to server MAC", clientKexInit.MACsClientServer, serverKexInit.MACsClientServer, isClient)
if err != nil {
return
}
}
if !aeadCiphers[stoc.Cipher] {
stoc.MAC, err = findCommon("server to client MAC", clientKexInit.MACsServerClient, serverKexInit.MACsServerClient)
stoc.MAC, err = findCommon("server to client MAC", clientKexInit.MACsServerClient, serverKexInit.MACsServerClient, isClient)
if err != nil {
return
}
}
ctos.Compression, err = findCommon("client to server compression", clientKexInit.CompressionClientServer, serverKexInit.CompressionClientServer)
ctos.compression, err = findCommon("client to server compression", clientKexInit.CompressionClientServer, serverKexInit.CompressionClientServer, isClient)
if err != nil {
return
}
stoc.Compression, err = findCommon("server to client compression", clientKexInit.CompressionServerClient, serverKexInit.CompressionServerClient)
stoc.compression, err = findCommon("server to client compression", clientKexInit.CompressionServerClient, serverKexInit.CompressionServerClient, isClient)
if err != nil {
return
}
@@ -297,7 +545,7 @@ func (c *Config) SetDefaults() {
c.Rand = rand.Reader
}
if c.Ciphers == nil {
c.Ciphers = preferredCiphers
c.Ciphers = defaultCiphers
}
var ciphers []string
for _, c := range c.Ciphers {
@@ -309,19 +557,22 @@ func (c *Config) SetDefaults() {
c.Ciphers = ciphers
if c.KeyExchanges == nil {
c.KeyExchanges = preferredKexAlgos
c.KeyExchanges = defaultKexAlgos
}
var kexs []string
for _, k := range c.KeyExchanges {
if kexAlgoMap[k] != nil {
// Ignore the KEX if we have no kexAlgoMap definition.
kexs = append(kexs, k)
if k == KeyExchangeCurve25519 && !slices.Contains(c.KeyExchanges, keyExchangeCurve25519LibSSH) {
kexs = append(kexs, keyExchangeCurve25519LibSSH)
}
}
}
c.KeyExchanges = kexs
if c.MACs == nil {
c.MACs = supportedMACs
c.MACs = defaultMACs
}
var macs []string
for _, m := range c.MACs {

View File

@@ -74,6 +74,13 @@ type Conn interface {
// Disconnect
}
// AlgorithmsConnMetadata is a ConnMetadata that can return the algorithms
// negotiated between client and server.
type AlgorithmsConnMetadata interface {
ConnMetadata
Algorithms() NegotiatedAlgorithms
}
// DiscardRequests consumes and rejects all requests from the
// passed-in channel.
func DiscardRequests(in <-chan *Request) {
@@ -106,6 +113,7 @@ type sshConn struct {
sessionID []byte
clientVersion []byte
serverVersion []byte
algorithms NegotiatedAlgorithms
}
func dup(src []byte) []byte {
@@ -141,3 +149,7 @@ func (c *sshConn) ClientVersion() []byte {
func (c *sshConn) ServerVersion() []byte {
return dup(c.serverVersion)
}
func (c *sshConn) Algorithms() NegotiatedAlgorithms {
return c.algorithms
}

View File

@@ -16,8 +16,19 @@ References:
[PROTOCOL]: https://cvsweb.openbsd.org/cgi-bin/cvsweb/src/usr.bin/ssh/PROTOCOL?rev=HEAD
[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
[SSH-CERTS]: https://datatracker.ietf.org/doc/html/draft-miller-ssh-cert-01
[FIPS 140-3 mode]: https://go.dev/doc/security/fips140
This package does not fall under the stability promise of the Go language itself,
so its API may be changed when pressing needs arise.
# FIPS 140-3 mode
When the program is in [FIPS 140-3 mode], this package behaves as if only SP
800-140C and SP 800-140D approved cipher suites, signature algorithms,
certificate public key types and sizes, and key exchange and derivation
algorithms were implemented. Others are silently ignored and not negotiated, or
rejected. This set may depend on the algorithms supported by the FIPS 140-3 Go
Cryptographic Module selected with GOFIPS140, and may change across Go versions.
*/
package ssh // import "golang.org/x/crypto/ssh"
package ssh

View File

@@ -5,12 +5,12 @@
package ssh
import (
"crypto/rand"
"errors"
"fmt"
"io"
"log"
"net"
"slices"
"strings"
"sync"
)
@@ -25,6 +25,11 @@ const debugHandshake = false
// quickly.
const chanSize = 16
// maxPendingPackets sets the maximum number of packets to queue while waiting
// for KEX to complete. This limits the total pending data to maxPendingPackets
// * maxPacket bytes, which is ~16.8MB.
const maxPendingPackets = 64
// keyingTransport is a packet based transport that supports key
// changes. It need not be thread-safe. It should pass through
// msgNewKeys in both directions.
@@ -34,7 +39,7 @@ type keyingTransport interface {
// prepareKeyChange sets up a key change. The key change for a
// direction will be effected if a msgNewKeys message is sent
// or received.
prepareKeyChange(*algorithms, *kexResult) error
prepareKeyChange(*NegotiatedAlgorithms, *kexResult) error
// setStrictMode sets the strict KEX mode, notably triggering
// sequence number resets on sending or receiving msgNewKeys.
@@ -73,13 +78,22 @@ 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
// Condition for the above mutex. It is used to notify a completed key
// exchange or a write failure. Writes can wait for this condition while a
// key exchange is in progress.
writeCond *sync.Cond
writeError error
sentInitPacket []byte
sentInitMsg *kexInitMsg
// Used to queue writes when a key exchange is in progress. The length is
// limited by pendingPacketsSize. Once full, writes will block until the key
// exchange is completed or an error occurs. If not empty, it is emptied
// all at once when the key exchange is completed in kexLoop.
pendingPackets [][]byte
writePacketsLeft uint32
writeBytesLeft int64
userAuthComplete bool // whether the user authentication phase is complete
// If the read loop wants to schedule a kex, it pings this
// channel, and the write loop will send out a kex
@@ -102,7 +116,7 @@ type handshakeTransport struct {
bannerCallback BannerCallback
// Algorithms agreed in the last key exchange.
algorithms *algorithms
algorithms *NegotiatedAlgorithms
// Counters exclusively owned by readLoop.
readPacketsLeft uint32
@@ -133,6 +147,7 @@ func newHandshakeTransport(conn keyingTransport, config *Config, clientVersion,
config: config,
}
t.writeCond = sync.NewCond(&t.mu)
t.resetReadThresholds()
t.resetWriteThresholds()
@@ -150,7 +165,7 @@ func newClientTransport(conn keyingTransport, clientVersion, serverVersion []byt
if config.HostKeyAlgorithms != nil {
t.hostKeyAlgorithms = config.HostKeyAlgorithms
} else {
t.hostKeyAlgorithms = supportedHostKeyAlgos
t.hostKeyAlgorithms = defaultHostKeyAlgos
}
go t.readLoop()
go t.kexLoop()
@@ -170,6 +185,10 @@ func (t *handshakeTransport) getSessionID() []byte {
return t.sessionID
}
func (t *handshakeTransport) getAlgorithms() NegotiatedAlgorithms {
return *t.algorithms
}
// waitSession waits for the session to be established. This should be
// the first thing to call after instantiating handshakeTransport.
func (t *handshakeTransport) waitSession() error {
@@ -259,6 +278,7 @@ func (t *handshakeTransport) recordWriteError(err error) {
defer t.mu.Unlock()
if t.writeError == nil && err != nil {
t.writeError = err
t.writeCond.Broadcast()
}
}
@@ -275,7 +295,7 @@ func (t *handshakeTransport) resetWriteThresholds() {
if t.config.RekeyThreshold > 0 {
t.writeBytesLeft = int64(t.config.RekeyThreshold)
} else if t.algorithms != nil {
t.writeBytesLeft = t.algorithms.w.rekeyBytes()
t.writeBytesLeft = t.algorithms.Write.rekeyBytes()
} else {
t.writeBytesLeft = 1 << 30
}
@@ -362,6 +382,8 @@ write:
}
}
t.pendingPackets = t.pendingPackets[:0]
// Unblock writePacket if waiting for KEX.
t.writeCond.Broadcast()
t.mu.Unlock()
}
@@ -390,7 +412,7 @@ func (t *handshakeTransport) resetReadThresholds() {
if t.config.RekeyThreshold > 0 {
t.readBytesLeft = int64(t.config.RekeyThreshold)
} else if t.algorithms != nil {
t.readBytesLeft = t.algorithms.r.rekeyBytes()
t.readBytesLeft = t.algorithms.Read.rekeyBytes()
} else {
t.readBytesLeft = 1 << 30
}
@@ -483,7 +505,7 @@ func (t *handshakeTransport) sendKexInit() error {
CompressionClientServer: supportedCompressions,
CompressionServerClient: supportedCompressions,
}
io.ReadFull(rand.Reader, msg.Cookie[:])
io.ReadFull(t.config.Rand, msg.Cookie[:])
// We mutate the KexAlgos slice, in order to add the kex-strict extension algorithm,
// and possibly to add the ext-info extension algorithm. Since the slice may be the
@@ -506,7 +528,7 @@ func (t *handshakeTransport) sendKexInit() error {
switch s := k.(type) {
case MultiAlgorithmSigner:
for _, algo := range algorithmsForKeyFormat(keyFormat) {
if contains(s.Algorithms(), underlyingAlgo(algo)) {
if slices.Contains(s.Algorithms(), underlyingAlgo(algo)) {
msg.ServerHostKeyAlgos = append(msg.ServerHostKeyAlgos, algo)
}
}
@@ -552,26 +574,44 @@ func (t *handshakeTransport) sendKexInit() error {
return nil
}
var errSendBannerPhase = errors.New("ssh: SendAuthBanner outside of authentication phase")
func (t *handshakeTransport) writePacket(p []byte) error {
t.mu.Lock()
defer t.mu.Unlock()
switch p[0] {
case msgKexInit:
return errors.New("ssh: only handshakeTransport can send kexInit")
case msgNewKeys:
return errors.New("ssh: only handshakeTransport can send newKeys")
case msgUserAuthBanner:
if t.userAuthComplete {
return errSendBannerPhase
}
case msgUserAuthSuccess:
t.userAuthComplete = true
}
t.mu.Lock()
defer t.mu.Unlock()
if t.writeError != nil {
return t.writeError
}
if t.sentInitMsg != nil {
// Copy the packet so the writer can reuse the buffer.
cp := make([]byte, len(p))
copy(cp, p)
t.pendingPackets = append(t.pendingPackets, cp)
return nil
if len(t.pendingPackets) < maxPendingPackets {
// Copy the packet so the writer can reuse the buffer.
cp := make([]byte, len(p))
copy(cp, p)
t.pendingPackets = append(t.pendingPackets, cp)
return nil
}
for t.sentInitMsg != nil {
// Block and wait for KEX to complete or an error.
t.writeCond.Wait()
if t.writeError != nil {
return t.writeError
}
}
}
if t.writeBytesLeft > 0 {
@@ -588,6 +628,7 @@ func (t *handshakeTransport) writePacket(p []byte) error {
if err := t.pushPacket(p); err != nil {
t.writeError = err
t.writeCond.Broadcast()
}
return nil
@@ -639,7 +680,7 @@ func (t *handshakeTransport) enterKeyExchange(otherInitPacket []byte) error {
return err
}
if t.sessionID == nil && ((isClient && contains(serverInit.KexAlgos, kexStrictServer)) || (!isClient && contains(clientInit.KexAlgos, kexStrictClient))) {
if t.sessionID == nil && ((isClient && slices.Contains(serverInit.KexAlgos, kexStrictServer)) || (!isClient && slices.Contains(clientInit.KexAlgos, kexStrictClient))) {
t.strictMode = true
if err := t.conn.setStrictMode(); err != nil {
return err
@@ -664,9 +705,9 @@ func (t *handshakeTransport) enterKeyExchange(otherInitPacket []byte) error {
}
}
kex, ok := kexAlgoMap[t.algorithms.kex]
kex, ok := kexAlgoMap[t.algorithms.KeyExchange]
if !ok {
return fmt.Errorf("ssh: unexpected key exchange algorithm %v", t.algorithms.kex)
return fmt.Errorf("ssh: unexpected key exchange algorithm %v", t.algorithms.KeyExchange)
}
var result *kexResult
@@ -696,7 +737,7 @@ func (t *handshakeTransport) enterKeyExchange(otherInitPacket []byte) error {
// 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, and [PROTOCOL], Section 1.9.
if !isClient && firstKeyExchange && contains(clientInit.KexAlgos, "ext-info-c") {
if !isClient && firstKeyExchange && slices.Contains(clientInit.KexAlgos, "ext-info-c") {
supportedPubKeyAuthAlgosList := strings.Join(t.publicKeyAuthAlgorithms, ",")
extInfo := &extInfoMsg{
NumExtensions: 2,
@@ -750,7 +791,7 @@ func (a algorithmSignerWrapper) SignWithAlgorithm(rand io.Reader, data []byte, a
func pickHostKey(hostKeys []Signer, algo string) AlgorithmSigner {
for _, k := range hostKeys {
if s, ok := k.(MultiAlgorithmSigner); ok {
if !contains(s.Algorithms(), underlyingAlgo(algo)) {
if !slices.Contains(s.Algorithms(), underlyingAlgo(algo)) {
continue
}
}
@@ -773,12 +814,12 @@ func pickHostKey(hostKeys []Signer, algo string) AlgorithmSigner {
}
func (t *handshakeTransport) server(kex kexAlgorithm, magics *handshakeMagics) (*kexResult, error) {
hostKey := pickHostKey(t.hostKeys, t.algorithms.hostKey)
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)
r, err := kex.Server(t.conn, t.config.Rand, magics, hostKey, t.algorithms.HostKey)
return r, err
}
@@ -793,7 +834,7 @@ func (t *handshakeTransport) client(kex kexAlgorithm, magics *handshakeMagics) (
return nil, err
}
if err := verifyHostKeySignature(hostKey, t.algorithms.hostKey, result); err != nil {
if err := verifyHostKeySignature(hostKey, t.algorithms.HostKey, result); err != nil {
return nil, err
}

155
vendor/golang.org/x/crypto/ssh/kex.go generated vendored
View File

@@ -8,33 +8,31 @@ import (
"crypto"
"crypto/ecdsa"
"crypto/elliptic"
"crypto/fips140"
"crypto/rand"
"crypto/subtle"
"encoding/binary"
"errors"
"fmt"
"io"
"math/big"
"slices"
"golang.org/x/crypto/curve25519"
)
const (
kexAlgoDH1SHA1 = "diffie-hellman-group1-sha1"
kexAlgoDH14SHA1 = "diffie-hellman-group14-sha1"
kexAlgoDH14SHA256 = "diffie-hellman-group14-sha256"
kexAlgoDH16SHA512 = "diffie-hellman-group16-sha512"
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
// implementation to satisfy the automated tests.
kexAlgoDHGEXSHA1 = "diffie-hellman-group-exchange-sha1"
kexAlgoDHGEXSHA256 = "diffie-hellman-group-exchange-sha256"
// This is the group called diffie-hellman-group1-sha1 in RFC 4253 and
// Oakley Group 2 in RFC 2409.
oakleyGroup2 = "FFFFFFFFFFFFFFFFC90FDAA22168C234C4C6628B80DC1CD129024E088A67CC74020BBEA63B139B22514A08798E3404DDEF9519B3CD3A431B302B0A6DF25F14374FE1356D6D51C245E485B576625E7EC6F44C42E9A637ED6B0BFF5CB6F406B7EDEE386BFB5A899FA5AE9F24117C4B1FE649286651ECE65381FFFFFFFFFFFFFFFF"
// This is the group called diffie-hellman-group14-sha1 in RFC 4253 and
// Oakley Group 14 in RFC 3526.
oakleyGroup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
// This is the group called diffie-hellman-group15-sha512 in RFC 8268 and
// Oakley Group 15 in RFC 3526.
oakleyGroup15 = "FFFFFFFFFFFFFFFFC90FDAA22168C234C4C6628B80DC1CD129024E088A67CC74020BBEA63B139B22514A08798E3404DDEF9519B3CD3A431B302B0A6DF25F14374FE1356D6D51C245E485B576625E7EC6F44C42E9A637ED6B0BFF5CB6F406B7EDEE386BFB5A899FA5AE9F24117C4B1FE649286651ECE45B3DC2007CB8A163BF0598DA48361C55D39A69163FA8FD24CF5F83655D23DCA3AD961C62F356208552BB9ED529077096966D670C354E4ABC9804F1746C08CA18217C32905E462E36CE3BE39E772C180E86039B2783A2EC07A28FB5C55DF06F4C52C9DE2BCBF6955817183995497CEA956AE515D2261898FA051015728E5A8AAAC42DAD33170D04507A33A85521ABDF1CBA64ECFB850458DBEF0A8AEA71575D060C7DB3970F85A6E1E4C7ABF5AE8CDB0933D71E8C94E04A25619DCEE3D2261AD2EE6BF12FFA06D98A0864D87602733EC86A64521F2B18177B200CBBE117577A615D6C770988C0BAD946E208E24FA074E5AB3143DB5BFCE0FD108E4B82D120A93AD2CAFFFFFFFFFFFFFFFF"
// This is the group called diffie-hellman-group16-sha512 in RFC 8268 and
// Oakley Group 16 in RFC 3526.
oakleyGroup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
)
// kexResult captures the outcome of a key exchange.
@@ -399,56 +397,64 @@ func ecHash(curve elliptic.Curve) crypto.Hash {
return crypto.SHA512
}
// kexAlgoMap defines the supported KEXs. KEXs not included are not supported
// and will not be negotiated, even if explicitly configured. When FIPS mode is
// enabled, only FIPS-approved algorithms are included.
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.
p, _ := new(big.Int).SetString("FFFFFFFFFFFFFFFFC90FDAA22168C234C4C6628B80DC1CD129024E088A67CC74020BBEA63B139B22514A08798E3404DDEF9519B3CD3A431B302B0A6DF25F14374FE1356D6D51C245E485B576625E7EC6F44C42E9A637ED6B0BFF5CB6F406B7EDEE386BFB5A899FA5AE9F24117C4B1FE649286651ECE65381FFFFFFFFFFFFFFFF", 16)
kexAlgoMap[kexAlgoDH1SHA1] = &dhGroup{
// mlkem768x25519-sha256 we'll work with fips140=on but not fips140=only
// until Go 1.26.
kexAlgoMap[KeyExchangeMLKEM768X25519] = &mlkem768WithCurve25519sha256{}
kexAlgoMap[KeyExchangeECDHP521] = &ecdh{elliptic.P521()}
kexAlgoMap[KeyExchangeECDHP384] = &ecdh{elliptic.P384()}
kexAlgoMap[KeyExchangeECDHP256] = &ecdh{elliptic.P256()}
if fips140.Enabled() {
defaultKexAlgos = slices.DeleteFunc(defaultKexAlgos, func(algo string) bool {
_, ok := kexAlgoMap[algo]
return !ok
})
return
}
p, _ := new(big.Int).SetString(oakleyGroup2, 16)
kexAlgoMap[InsecureKeyExchangeDH1SHA1] = &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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
p, _ = new(big.Int).SetString(oakleyGroup14, 16)
group14 := &dhGroup{
g: new(big.Int).SetInt64(2),
p: p,
pMinus1: new(big.Int).Sub(p, bigOne),
}
kexAlgoMap[kexAlgoDH14SHA1] = &dhGroup{
kexAlgoMap[InsecureKeyExchangeDH14SHA1] = &dhGroup{
g: group14.g, p: group14.p, pMinus1: group14.pMinus1,
hashFunc: crypto.SHA1,
}
kexAlgoMap[kexAlgoDH14SHA256] = &dhGroup{
kexAlgoMap[KeyExchangeDH14SHA256] = &dhGroup{
g: group14.g, p: group14.p, pMinus1: group14.pMinus1,
hashFunc: crypto.SHA256,
}
// This is the group called diffie-hellman-group16-sha512 in RFC
// 8268 and Oakley Group 16 in RFC 3526.
p, _ = new(big.Int).SetString("FFFFFFFFFFFFFFFFC90FDAA22168C234C4C6628B80DC1CD129024E088A67CC74020BBEA63B139B22514A08798E3404DDEF9519B3CD3A431B302B0A6DF25F14374FE1356D6D51C245E485B576625E7EC6F44C42E9A637ED6B0BFF5CB6F406B7EDEE386BFB5A899FA5AE9F24117C4B1FE649286651ECE45B3DC2007CB8A163BF0598DA48361C55D39A69163FA8FD24CF5F83655D23DCA3AD961C62F356208552BB9ED529077096966D670C354E4ABC9804F1746C08CA18217C32905E462E36CE3BE39E772C180E86039B2783A2EC07A28FB5C55DF06F4C52C9DE2BCBF6955817183995497CEA956AE515D2261898FA051015728E5A8AAAC42DAD33170D04507A33A85521ABDF1CBA64ECFB850458DBEF0A8AEA71575D060C7DB3970F85A6E1E4C7ABF5AE8CDB0933D71E8C94E04A25619DCEE3D2261AD2EE6BF12FFA06D98A0864D87602733EC86A64521F2B18177B200CBBE117577A615D6C770988C0BAD946E208E24FA074E5AB3143DB5BFCE0FD108E4B82D120A92108011A723C12A787E6D788719A10BDBA5B2699C327186AF4E23C1A946834B6150BDA2583E9CA2AD44CE8DBBBC2DB04DE8EF92E8EFC141FBECAA6287C59474E6BC05D99B2964FA090C3A2233BA186515BE7ED1F612970CEE2D7AFB81BDD762170481CD0069127D5B05AA993B4EA988D8FDDC186FFB7DC90A6C08F4DF435C934063199FFFFFFFFFFFFFFFF", 16)
p, _ = new(big.Int).SetString(oakleyGroup16, 16)
kexAlgoMap[kexAlgoDH16SHA512] = &dhGroup{
kexAlgoMap[KeyExchangeDH16SHA512] = &dhGroup{
g: new(big.Int).SetInt64(2),
p: p,
pMinus1: new(big.Int).Sub(p, bigOne),
hashFunc: crypto.SHA512,
}
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}
kexAlgoMap[KeyExchangeCurve25519] = &curve25519sha256{}
kexAlgoMap[keyExchangeCurve25519LibSSH] = &curve25519sha256{}
kexAlgoMap[InsecureKeyExchangeDHGEXSHA1] = &dhGEXSHA{hashFunc: crypto.SHA1}
kexAlgoMap[KeyExchangeDHGEXSHA256] = &dhGEXSHA{hashFunc: crypto.SHA256}
}
// curve25519sha256 implements the curve25519-sha256 (formerly known as
@@ -464,15 +470,17 @@ func (kp *curve25519KeyPair) generate(rand io.Reader) error {
if _, err := io.ReadFull(rand, kp.priv[:]); err != nil {
return err
}
curve25519.ScalarBaseMult(&kp.pub, &kp.priv)
p, err := curve25519.X25519(kp.priv[:], curve25519.Basepoint)
if err != nil {
return fmt.Errorf("curve25519: %w", err)
}
if len(p) != 32 {
return fmt.Errorf("curve25519: internal error: X25519 returned %d bytes, expected 32", len(p))
}
copy(kp.pub[:], p)
return nil
}
// curve25519Zeros is just an array of 32 zero bytes so that we have something
// convenient to compare against in order to reject curve25519 points with the
// wrong order.
var curve25519Zeros [32]byte
func (kex *curve25519sha256) Client(c packetConn, rand io.Reader, magics *handshakeMagics) (*kexResult, error) {
var kp curve25519KeyPair
if err := kp.generate(rand); err != nil {
@@ -495,11 +503,9 @@ func (kex *curve25519sha256) Client(c packetConn, rand io.Reader, magics *handsh
return nil, errors.New("ssh: peer's curve25519 public value has wrong length")
}
var servPub, secret [32]byte
copy(servPub[:], reply.EphemeralPubKey)
curve25519.ScalarMult(&secret, &kp.priv, &servPub)
if subtle.ConstantTimeCompare(secret[:], curve25519Zeros[:]) == 1 {
return nil, errors.New("ssh: peer's curve25519 public value has wrong order")
secret, err := curve25519.X25519(kp.priv[:], reply.EphemeralPubKey)
if err != nil {
return nil, fmt.Errorf("ssh: peer's curve25519 public value is not valid: %w", err)
}
h := crypto.SHA256.New()
@@ -541,11 +547,9 @@ func (kex *curve25519sha256) Server(c packetConn, rand io.Reader, magics *handsh
return nil, err
}
var clientPub, secret [32]byte
copy(clientPub[:], kexInit.ClientPubKey)
curve25519.ScalarMult(&secret, &kp.priv, &clientPub)
if subtle.ConstantTimeCompare(secret[:], curve25519Zeros[:]) == 1 {
return nil, errors.New("ssh: peer's curve25519 public value has wrong order")
secret, err := curve25519.X25519(kp.priv[:], kexInit.ClientPubKey)
if err != nil {
return nil, fmt.Errorf("ssh: peer's curve25519 public value is not valid: %w", err)
}
hostKeyBytes := priv.PublicKey().Marshal()
@@ -601,9 +605,9 @@ const (
func (gex *dhGEXSHA) Client(c packetConn, randSource io.Reader, magics *handshakeMagics) (*kexResult, error) {
// Send GexRequest
kexDHGexRequest := kexDHGexRequestMsg{
MinBits: dhGroupExchangeMinimumBits,
PreferedBits: dhGroupExchangePreferredBits,
MaxBits: dhGroupExchangeMaximumBits,
MinBits: dhGroupExchangeMinimumBits,
PreferredBits: dhGroupExchangePreferredBits,
MaxBits: dhGroupExchangeMaximumBits,
}
if err := c.writePacket(Marshal(&kexDHGexRequest)); err != nil {
return nil, err
@@ -690,9 +694,7 @@ func (gex *dhGEXSHA) Client(c packetConn, randSource io.Reader, magics *handshak
}
// 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 AlgorithmSigner, algo string) (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 {
@@ -702,13 +704,32 @@ func (gex dhGEXSHA) Server(c packetConn, randSource io.Reader, magics *handshake
if err = Unmarshal(packet, &kexDHGexRequest); err != nil {
return
}
// We check that the request received is valid and that the MaxBits
// requested are at least equal to our supported minimum. This is the same
// check done in OpenSSH:
// https://github.com/openssh/openssh-portable/blob/80a2f64b/kexgexs.c#L94
//
// Furthermore, we also check that the required MinBits are less than or
// equal to 4096 because we can use up to Oakley Group 16.
if kexDHGexRequest.MaxBits < kexDHGexRequest.MinBits || kexDHGexRequest.PreferredBits < kexDHGexRequest.MinBits ||
kexDHGexRequest.MaxBits < kexDHGexRequest.PreferredBits || kexDHGexRequest.MaxBits < dhGroupExchangeMinimumBits ||
kexDHGexRequest.MinBits > 4096 {
return nil, fmt.Errorf("ssh: DH GEX request out of range, min: %d, max: %d, preferred: %d", kexDHGexRequest.MinBits,
kexDHGexRequest.MaxBits, kexDHGexRequest.PreferredBits)
}
var p *big.Int
// We hardcode sending Oakley Group 14 (2048 bits), Oakley Group 15 (3072
// bits) or Oakley Group 16 (4096 bits), based on the requested max size.
if kexDHGexRequest.MaxBits < 3072 {
p, _ = new(big.Int).SetString(oakleyGroup14, 16)
} else if kexDHGexRequest.MaxBits < 4096 {
p, _ = new(big.Int).SetString(oakleyGroup15, 16)
} else {
p, _ = new(big.Int).SetString(oakleyGroup16, 16)
}
// 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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
g := big.NewInt(2)
msg := &kexDHGexGroupMsg{
P: p,
G: g,
@@ -746,9 +767,9 @@ func (gex dhGEXSHA) Server(c packetConn, randSource io.Reader, magics *handshake
h := gex.hashFunc.New()
magics.write(h)
writeString(h, hostKeyBytes)
binary.Write(h, binary.BigEndian, uint32(dhGroupExchangeMinimumBits))
binary.Write(h, binary.BigEndian, uint32(dhGroupExchangePreferredBits))
binary.Write(h, binary.BigEndian, uint32(dhGroupExchangeMaximumBits))
binary.Write(h, binary.BigEndian, kexDHGexRequest.MinBits)
binary.Write(h, binary.BigEndian, kexDHGexRequest.PreferredBits)
binary.Write(h, binary.BigEndian, kexDHGexRequest.MaxBits)
writeInt(h, p)
writeInt(h, g)
writeInt(h, kexDHGexInit.X)

View File

@@ -27,6 +27,7 @@ import (
"fmt"
"io"
"math/big"
"slices"
"strings"
"golang.org/x/crypto/ssh/internal/bcrypt_pbkdf"
@@ -36,14 +37,19 @@ import (
// ClientConfig.HostKeyAlgorithms, Signature.Format, or as AlgorithmSigner
// arguments.
const (
KeyAlgoRSA = "ssh-rsa"
KeyAlgoDSA = "ssh-dss"
KeyAlgoECDSA256 = "ecdsa-sha2-nistp256"
KeyAlgoSKECDSA256 = "sk-ecdsa-sha2-nistp256@openssh.com"
KeyAlgoECDSA384 = "ecdsa-sha2-nistp384"
KeyAlgoECDSA521 = "ecdsa-sha2-nistp521"
KeyAlgoED25519 = "ssh-ed25519"
KeyAlgoSKED25519 = "sk-ssh-ed25519@openssh.com"
KeyAlgoRSA = "ssh-rsa"
// Deprecated: DSA is only supported at insecure key sizes, and was removed
// from major implementations.
KeyAlgoDSA = InsecureKeyAlgoDSA
// Deprecated: DSA is only supported at insecure key sizes, and was removed
// from major implementations.
InsecureKeyAlgoDSA = "ssh-dss"
KeyAlgoECDSA256 = "ecdsa-sha2-nistp256"
KeyAlgoSKECDSA256 = "sk-ecdsa-sha2-nistp256@openssh.com"
KeyAlgoECDSA384 = "ecdsa-sha2-nistp384"
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
@@ -67,7 +73,7 @@ func parsePubKey(in []byte, algo string) (pubKey PublicKey, rest []byte, err err
switch algo {
case KeyAlgoRSA:
return parseRSA(in)
case KeyAlgoDSA:
case InsecureKeyAlgoDSA:
return parseDSA(in)
case KeyAlgoECDSA256, KeyAlgoECDSA384, KeyAlgoECDSA521:
return parseECDSA(in)
@@ -77,13 +83,18 @@ func parsePubKey(in []byte, algo string) (pubKey PublicKey, rest []byte, err err
return parseED25519(in)
case KeyAlgoSKED25519:
return parseSKEd25519(in)
case CertAlgoRSAv01, CertAlgoDSAv01, CertAlgoECDSA256v01, CertAlgoECDSA384v01, CertAlgoECDSA521v01, CertAlgoSKECDSA256v01, CertAlgoED25519v01, CertAlgoSKED25519v01:
case CertAlgoRSAv01, InsecureCertAlgoDSAv01, CertAlgoECDSA256v01, CertAlgoECDSA384v01, CertAlgoECDSA521v01, CertAlgoSKECDSA256v01, CertAlgoED25519v01, CertAlgoSKED25519v01:
cert, err := parseCert(in, certKeyAlgoNames[algo])
if err != nil {
return nil, nil, err
}
return cert, nil, nil
}
if keyFormat := keyFormatForAlgorithm(algo); keyFormat != "" {
return nil, nil, fmt.Errorf("ssh: signature algorithm %q isn't a key format; key is malformed and should be re-encoded with type %q",
algo, keyFormat)
}
return nil, nil, fmt.Errorf("ssh: unknown key algorithm: %v", algo)
}
@@ -186,9 +197,10 @@ func ParseKnownHosts(in []byte) (marker string, hosts []string, pubKey PublicKey
return "", nil, nil, "", nil, io.EOF
}
// ParseAuthorizedKey parses a public key from an authorized_keys
// file used in OpenSSH according to the sshd(8) manual page.
// ParseAuthorizedKey parses a public key from an authorized_keys file used in
// OpenSSH according to the sshd(8) manual page. Invalid lines are ignored.
func ParseAuthorizedKey(in []byte) (out PublicKey, comment string, options []string, rest []byte, err error) {
var lastErr error
for len(in) > 0 {
end := bytes.IndexByte(in, '\n')
if end != -1 {
@@ -217,6 +229,8 @@ func ParseAuthorizedKey(in []byte) (out PublicKey, comment string, options []str
if out, comment, err = parseAuthorizedKey(in[i:]); err == nil {
return out, comment, options, rest, nil
} else {
lastErr = err
}
// No key type recognised. Maybe there's an options field at
@@ -259,16 +273,22 @@ func ParseAuthorizedKey(in []byte) (out PublicKey, comment string, options []str
if out, comment, err = parseAuthorizedKey(in[i:]); err == nil {
options = candidateOptions
return out, comment, options, rest, nil
} else {
lastErr = err
}
in = rest
continue
}
if lastErr != nil {
return nil, "", nil, nil, fmt.Errorf("ssh: no key found; last parsing error for ignored line: %w", lastErr)
}
return nil, "", nil, nil, errors.New("ssh: no key found")
}
// ParsePublicKey parses an SSH public key formatted for use in
// ParsePublicKey parses an SSH public key or certificate formatted for use in
// the SSH wire protocol according to RFC 4253, section 6.6.
func ParsePublicKey(in []byte) (out PublicKey, err error) {
algo, in, ok := parseString(in)
@@ -390,11 +410,11 @@ func NewSignerWithAlgorithms(signer AlgorithmSigner, algorithms []string) (Multi
}
for _, algo := range algorithms {
if !contains(supportedAlgos, algo) {
if !slices.Contains(supportedAlgos, algo) {
return nil, fmt.Errorf("ssh: algorithm %q is not supported for key type %q",
algo, signer.PublicKey().Type())
}
if !contains(signerAlgos, algo) {
if !slices.Contains(signerAlgos, algo) {
return nil, fmt.Errorf("ssh: algorithm %q is restricted for the provided signer", algo)
}
}
@@ -481,14 +501,59 @@ func (r *rsaPublicKey) Marshal() []byte {
func (r *rsaPublicKey) Verify(data []byte, sig *Signature) error {
supportedAlgos := algorithmsForKeyFormat(r.Type())
if !contains(supportedAlgos, sig.Format) {
if !slices.Contains(supportedAlgos, sig.Format) {
return fmt.Errorf("ssh: signature type %s for key type %s", sig.Format, r.Type())
}
hash := hashFuncs[sig.Format]
hash, err := hashFunc(sig.Format)
if err != nil {
return err
}
h := hash.New()
h.Write(data)
digest := h.Sum(nil)
return rsa.VerifyPKCS1v15((*rsa.PublicKey)(r), hash, digest, sig.Blob)
// Signatures in PKCS1v15 must match the key's modulus in
// length. However with SSH, some signers provide RSA
// signatures which are missing the MSB 0's of the bignum
// represented. With ssh-rsa signatures, this is encouraged by
// the spec (even though e.g. OpenSSH will give the full
// length unconditionally). With rsa-sha2-* signatures, the
// verifier is allowed to support these, even though they are
// out of spec. See RFC 4253 Section 6.6 for ssh-rsa and RFC
// 8332 Section 3 for rsa-sha2-* details.
//
// In practice:
// * OpenSSH always allows "short" signatures:
// https://github.com/openssh/openssh-portable/blob/V_9_8_P1/ssh-rsa.c#L526
// but always generates padded signatures:
// https://github.com/openssh/openssh-portable/blob/V_9_8_P1/ssh-rsa.c#L439
//
// * PuTTY versions 0.81 and earlier will generate short
// signatures for all RSA signature variants. Note that
// PuTTY is embedded in other software, such as WinSCP and
// FileZilla. At the time of writing, a patch has been
// applied to PuTTY to generate padded signatures for
// rsa-sha2-*, but not yet released:
// https://git.tartarus.org/?p=simon/putty.git;a=commitdiff;h=a5bcf3d384e1bf15a51a6923c3724cbbee022d8e
//
// * SSH.NET versions 2024.0.0 and earlier will generate short
// signatures for all RSA signature variants, fixed in 2024.1.0:
// https://github.com/sshnet/SSH.NET/releases/tag/2024.1.0
//
// As a result, we pad these up to the key size by inserting
// leading 0's.
//
// Note that support for short signatures with rsa-sha2-* may
// be removed in the future due to such signatures not being
// allowed by the spec.
blob := sig.Blob
keySize := (*rsa.PublicKey)(r).Size()
if len(blob) < keySize {
padded := make([]byte, keySize)
copy(padded[keySize-len(blob):], blob)
blob = padded
}
return rsa.VerifyPKCS1v15((*rsa.PublicKey)(r), hash, digest, blob)
}
func (r *rsaPublicKey) CryptoPublicKey() crypto.PublicKey {
@@ -559,7 +624,11 @@ 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 := hashFuncs[sig.Format].New()
hash, err := hashFunc(sig.Format)
if err != nil {
return err
}
h := hash.New()
h.Write(data)
digest := h.Sum(nil)
@@ -604,7 +673,11 @@ func (k *dsaPrivateKey) SignWithAlgorithm(rand io.Reader, data []byte, algorithm
return nil, fmt.Errorf("ssh: unsupported signature algorithm %s", algorithm)
}
h := hashFuncs[k.PublicKey().Type()].New()
hash, err := hashFunc(k.PublicKey().Type())
if err != nil {
return nil, err
}
h := hash.New()
h.Write(data)
digest := h.Sum(nil)
r, s, err := dsa.Sign(rand, k.PrivateKey, digest)
@@ -754,8 +827,11 @@ func (k *ecdsaPublicKey) 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 := hashFuncs[sig.Format].New()
hash, err := hashFunc(sig.Format)
if err != nil {
return err
}
h := hash.New()
h.Write(data)
digest := h.Sum(nil)
@@ -858,8 +934,11 @@ func (k *skECDSAPublicKey) 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 := hashFuncs[sig.Format].New()
hash, err := hashFunc(sig.Format)
if err != nil {
return err
}
h := hash.New()
h.Write([]byte(k.application))
appDigest := h.Sum(nil)
@@ -904,6 +983,10 @@ func (k *skECDSAPublicKey) Verify(data []byte, sig *Signature) error {
return errors.New("ssh: signature did not verify")
}
func (k *skECDSAPublicKey) CryptoPublicKey() crypto.PublicKey {
return &k.PublicKey
}
type skEd25519PublicKey struct {
// application is a URL-like string, typically "ssh:" for SSH.
// see openssh/PROTOCOL.u2f for details.
@@ -958,7 +1041,11 @@ func (k *skEd25519PublicKey) Verify(data []byte, sig *Signature) error {
return fmt.Errorf("invalid size %d for Ed25519 public key", l)
}
h := hashFuncs[sig.Format].New()
hash, err := hashFunc(sig.Format)
if err != nil {
return err
}
h := hash.New()
h.Write([]byte(k.application))
appDigest := h.Sum(nil)
@@ -1000,6 +1087,10 @@ func (k *skEd25519PublicKey) Verify(data []byte, sig *Signature) error {
return nil
}
func (k *skEd25519PublicKey) CryptoPublicKey() crypto.PublicKey {
return k.PublicKey
}
// NewSignerFromKey takes an *rsa.PrivateKey, *dsa.PrivateKey,
// *ecdsa.PrivateKey or any other crypto.Signer and returns a
// corresponding Signer instance. ECDSA keys must use P-256, P-384 or
@@ -1057,11 +1148,14 @@ func (s *wrappedSigner) SignWithAlgorithm(rand io.Reader, data []byte, algorithm
algorithm = s.pubKey.Type()
}
if !contains(s.Algorithms(), algorithm) {
if !slices.Contains(s.Algorithms(), algorithm) {
return nil, fmt.Errorf("ssh: unsupported signature algorithm %q for key format %q", algorithm, s.pubKey.Type())
}
hashFunc := hashFuncs[algorithm]
hashFunc, err := hashFunc(algorithm)
if err != nil {
return nil, err
}
var digest []byte
if hashFunc != 0 {
h := hashFunc.New()
@@ -1396,6 +1490,7 @@ type openSSHEncryptedPrivateKey struct {
NumKeys uint32
PubKey []byte
PrivKeyBlock []byte
Rest []byte `ssh:"rest"`
}
type openSSHPrivateKey struct {

View File

@@ -302,8 +302,8 @@ func (k *KnownKey) String() string {
// applications can offer an interactive prompt to the user.
type KeyError struct {
// Want holds the accepted host keys. For each key algorithm,
// there can be one hostkey. If Want is empty, the host is
// unknown. If Want is non-empty, there was a mismatch, which
// there can be multiple hostkeys. If Want is empty, the host
// is unknown. If Want is non-empty, there was a mismatch, which
// can signify a MITM attack.
Want []KnownKey
}
@@ -358,34 +358,20 @@ func (db *hostKeyDB) checkAddr(a addr, remoteKey ssh.PublicKey) error {
// is just a key for the IP address, but not for the
// hostname?
// Algorithm => key.
knownKeys := map[string]KnownKey{}
keyErr := &KeyError{}
for _, l := range db.lines {
if l.match(a) {
typ := l.knownKey.Key.Type()
if _, ok := knownKeys[typ]; !ok {
knownKeys[typ] = l.knownKey
}
if !l.match(a) {
continue
}
keyErr.Want = append(keyErr.Want, l.knownKey)
if keyEq(l.knownKey.Key, remoteKey) {
return nil
}
}
keyErr := &KeyError{}
for _, v := range knownKeys {
keyErr.Want = append(keyErr.Want, v)
}
// Unknown remote host.
if len(knownKeys) == 0 {
return keyErr
}
// If the remote host starts using a different, unknown key type, we
// also interpret that as a mismatch.
if known, ok := knownKeys[remoteKey.Type()]; !ok || !keyEq(known.Key, remoteKey) {
return keyErr
}
return nil
return keyErr
}
// The Read function parses file contents.
@@ -435,20 +421,26 @@ func New(files ...string) (ssh.HostKeyCallback, error) {
return certChecker.CheckHostKey, nil
}
// Normalize normalizes an address into the form used in known_hosts
// Normalize normalizes an address into the form used in known_hosts. Supports
// IPv4, hostnames, bracketed IPv6. Any other non-standard formats are returned
// with minimal transformation.
func Normalize(address string) string {
const defaultSSHPort = "22"
host, port, err := net.SplitHostPort(address)
if err != nil {
host = address
port = "22"
port = defaultSSHPort
}
entry := host
if port != "22" {
entry = "[" + entry + "]:" + port
} else if strings.Contains(host, ":") && !strings.HasPrefix(host, "[") {
entry = "[" + entry + "]"
if strings.HasPrefix(host, "[") && strings.HasSuffix(host, "]") {
host = host[1 : len(host)-1]
}
return entry
if port == defaultSSHPort {
return host
}
return "[" + host + "]:" + port
}
// Line returns a line to add append to the known_hosts files.

View File

@@ -7,11 +7,13 @@ package ssh
// Message authentication support
import (
"crypto/fips140"
"crypto/hmac"
"crypto/sha1"
"crypto/sha256"
"crypto/sha512"
"hash"
"slices"
)
type macMode struct {
@@ -46,23 +48,37 @@ func (t truncatingMAC) Size() int {
func (t truncatingMAC) BlockSize() int { return t.hmac.BlockSize() }
var macModes = map[string]*macMode{
"hmac-sha2-512-etm@openssh.com": {64, true, func(key []byte) hash.Hash {
// macModes defines the supported MACs. MACs not included are not supported
// and will not be negotiated, even if explicitly configured. When FIPS mode is
// enabled, only FIPS-approved algorithms are included.
var macModes = map[string]*macMode{}
func init() {
macModes[HMACSHA512ETM] = &macMode{64, true, func(key []byte) hash.Hash {
return hmac.New(sha512.New, key)
}},
"hmac-sha2-256-etm@openssh.com": {32, true, func(key []byte) hash.Hash {
}}
macModes[HMACSHA256ETM] = &macMode{32, true, func(key []byte) hash.Hash {
return hmac.New(sha256.New, key)
}},
"hmac-sha2-512": {64, false, func(key []byte) hash.Hash {
}}
macModes[HMACSHA512] = &macMode{64, false, func(key []byte) hash.Hash {
return hmac.New(sha512.New, key)
}},
"hmac-sha2-256": {32, false, func(key []byte) hash.Hash {
}}
macModes[HMACSHA256] = &macMode{32, false, func(key []byte) hash.Hash {
return hmac.New(sha256.New, key)
}},
"hmac-sha1": {20, false, func(key []byte) hash.Hash {
}}
if fips140.Enabled() {
defaultMACs = slices.DeleteFunc(defaultMACs, func(algo string) bool {
_, ok := macModes[algo]
return !ok
})
return
}
macModes[HMACSHA1] = &macMode{20, false, func(key []byte) hash.Hash {
return hmac.New(sha1.New, key)
}},
"hmac-sha1-96": {20, false, func(key []byte) hash.Hash {
}}
macModes[InsecureHMACSHA196] = &macMode{20, false, func(key []byte) hash.Hash {
return truncatingMAC{12, hmac.New(sha1.New, key)}
}},
}}
}

View File

@@ -122,9 +122,9 @@ type kexDHGexReplyMsg struct {
const msgKexDHGexRequest = 34
type kexDHGexRequestMsg struct {
MinBits uint32 `sshtype:"34"`
PreferedBits uint32
MaxBits uint32
MinBits uint32 `sshtype:"34"`
PreferredBits uint32
MaxBits uint32
}
// See RFC 4253, section 10.
@@ -792,7 +792,7 @@ func marshalString(to []byte, s []byte) []byte {
return to[len(s):]
}
var bigIntType = reflect.TypeOf((*big.Int)(nil))
var bigIntType = reflect.TypeFor[*big.Int]()
// Decode a packet into its corresponding message.
func decode(packet []byte) (interface{}, error) {
@@ -818,6 +818,8 @@ func decode(packet []byte) (interface{}, error) {
return new(userAuthSuccessMsg), nil
case msgUserAuthFailure:
msg = new(userAuthFailureMsg)
case msgUserAuthBanner:
msg = new(userAuthBannerMsg)
case msgUserAuthPubKeyOk:
msg = new(userAuthPubKeyOkMsg)
case msgGlobalRequest:

168
vendor/golang.org/x/crypto/ssh/mlkem.go generated vendored Normal file
View File

@@ -0,0 +1,168 @@
// Copyright 2024 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 (
"crypto"
"crypto/mlkem"
"crypto/sha256"
"errors"
"fmt"
"io"
"golang.org/x/crypto/curve25519"
)
// mlkem768WithCurve25519sha256 implements the hybrid ML-KEM768 with
// curve25519-sha256 key exchange method, as described by
// draft-kampanakis-curdle-ssh-pq-ke-05 section 2.3.3.
type mlkem768WithCurve25519sha256 struct{}
func (kex *mlkem768WithCurve25519sha256) Client(c packetConn, rand io.Reader, magics *handshakeMagics) (*kexResult, error) {
var c25519kp curve25519KeyPair
if err := c25519kp.generate(rand); err != nil {
return nil, err
}
seed := make([]byte, mlkem.SeedSize)
if _, err := io.ReadFull(rand, seed); err != nil {
return nil, err
}
mlkemDk, err := mlkem.NewDecapsulationKey768(seed)
if err != nil {
return nil, err
}
hybridKey := append(mlkemDk.EncapsulationKey().Bytes(), c25519kp.pub[:]...)
if err := c.writePacket(Marshal(&kexECDHInitMsg{hybridKey})); err != nil {
return nil, err
}
packet, err := c.readPacket()
if err != nil {
return nil, err
}
var reply kexECDHReplyMsg
if err = Unmarshal(packet, &reply); err != nil {
return nil, err
}
if len(reply.EphemeralPubKey) != mlkem.CiphertextSize768+32 {
return nil, errors.New("ssh: peer's mlkem768x25519 public value has wrong length")
}
// Perform KEM decapsulate operation to obtain shared key from ML-KEM.
mlkem768Secret, err := mlkemDk.Decapsulate(reply.EphemeralPubKey[:mlkem.CiphertextSize768])
if err != nil {
return nil, err
}
// Complete Curve25519 ECDH to obtain its shared key.
c25519Secret, err := curve25519.X25519(c25519kp.priv[:], reply.EphemeralPubKey[mlkem.CiphertextSize768:])
if err != nil {
return nil, fmt.Errorf("ssh: peer's mlkem768x25519 public value is not valid: %w", err)
}
// Compute actual shared key.
h := sha256.New()
h.Write(mlkem768Secret)
h.Write(c25519Secret)
secret := h.Sum(nil)
h.Reset()
magics.write(h)
writeString(h, reply.HostKey)
writeString(h, hybridKey)
writeString(h, reply.EphemeralPubKey)
K := make([]byte, stringLength(len(secret)))
marshalString(K, secret)
h.Write(K)
return &kexResult{
H: h.Sum(nil),
K: K,
HostKey: reply.HostKey,
Signature: reply.Signature,
Hash: crypto.SHA256,
}, nil
}
func (kex *mlkem768WithCurve25519sha256) Server(c packetConn, rand io.Reader, magics *handshakeMagics, priv AlgorithmSigner, algo string) (*kexResult, error) {
packet, err := c.readPacket()
if err != nil {
return nil, err
}
var kexInit kexECDHInitMsg
if err = Unmarshal(packet, &kexInit); err != nil {
return nil, err
}
if len(kexInit.ClientPubKey) != mlkem.EncapsulationKeySize768+32 {
return nil, errors.New("ssh: peer's ML-KEM768/curve25519 public value has wrong length")
}
encapsulationKey, err := mlkem.NewEncapsulationKey768(kexInit.ClientPubKey[:mlkem.EncapsulationKeySize768])
if err != nil {
return nil, fmt.Errorf("ssh: peer's ML-KEM768 encapsulation key is not valid: %w", err)
}
// Perform KEM encapsulate operation to obtain ciphertext and shared key.
mlkem768Secret, mlkem768Ciphertext := encapsulationKey.Encapsulate()
// Perform server side of Curve25519 ECDH to obtain server public value and
// shared key.
var c25519kp curve25519KeyPair
if err := c25519kp.generate(rand); err != nil {
return nil, err
}
c25519Secret, err := curve25519.X25519(c25519kp.priv[:], kexInit.ClientPubKey[mlkem.EncapsulationKeySize768:])
if err != nil {
return nil, fmt.Errorf("ssh: peer's ML-KEM768/curve25519 public value is not valid: %w", err)
}
hybridKey := append(mlkem768Ciphertext, c25519kp.pub[:]...)
// Compute actual shared key.
h := sha256.New()
h.Write(mlkem768Secret)
h.Write(c25519Secret)
secret := h.Sum(nil)
hostKeyBytes := priv.PublicKey().Marshal()
h.Reset()
magics.write(h)
writeString(h, hostKeyBytes)
writeString(h, kexInit.ClientPubKey)
writeString(h, hybridKey)
K := make([]byte, stringLength(len(secret)))
marshalString(K, secret)
h.Write(K)
H := h.Sum(nil)
sig, err := signAndMarshal(priv, rand, H, algo)
if err != nil {
return nil, err
}
reply := kexECDHReplyMsg{
EphemeralPubKey: hybridKey,
HostKey: hostKeyBytes,
Signature: sig,
}
if err := c.writePacket(Marshal(&reply)); err != nil {
return nil, err
}
return &kexResult{
H: H,
K: K,
HostKey: hostKeyBytes,
Signature: sig,
Hash: crypto.SHA256,
}, nil
}

View File

@@ -10,6 +10,7 @@ import (
"fmt"
"io"
"net"
"slices"
"strings"
)
@@ -43,6 +44,9 @@ type Permissions struct {
// pass data from the authentication callbacks to the server
// application layer.
Extensions map[string]string
// ExtraData allows to store user defined data.
ExtraData map[any]any
}
type GSSAPIWithMICConfig struct {
@@ -59,6 +63,27 @@ type GSSAPIWithMICConfig struct {
Server GSSAPIServer
}
// SendAuthBanner implements [ServerPreAuthConn].
func (s *connection) SendAuthBanner(msg string) error {
return s.transport.writePacket(Marshal(&userAuthBannerMsg{
Message: msg,
}))
}
func (*connection) unexportedMethodForFutureProofing() {}
// ServerPreAuthConn is the interface available on an incoming server
// connection before authentication has completed.
type ServerPreAuthConn interface {
unexportedMethodForFutureProofing() // permits growing ServerPreAuthConn safely later, ala testing.TB
ConnMetadata
// SendAuthBanner sends a banner message to the client.
// It returns an error once the authentication phase has ended.
SendAuthBanner(string) error
}
// ServerConfig holds server specific configuration data.
type ServerConfig struct {
// Config contains configuration shared between client and server.
@@ -105,6 +130,21 @@ type ServerConfig struct {
// Permissions.Extensions entry.
PublicKeyCallback func(conn ConnMetadata, key PublicKey) (*Permissions, error)
// VerifiedPublicKeyCallback, if non-nil, is called after a client
// successfully confirms having control over a key that was previously
// approved by PublicKeyCallback. The permissions object passed to the
// callback is the one returned by PublicKeyCallback for the given public
// key and its ownership is transferred to the callback. The returned
// Permissions object can be the same object, optionally modified, or a
// completely new object. If VerifiedPublicKeyCallback is non-nil,
// PublicKeyCallback is not allowed to return a PartialSuccessError, which
// can instead be returned by VerifiedPublicKeyCallback.
//
// VerifiedPublicKeyCallback does not affect which authentication methods
// are included in the list of methods that can be attempted by the client.
VerifiedPublicKeyCallback func(conn ConnMetadata, key PublicKey, permissions *Permissions,
signatureAlgorithm string) (*Permissions, error)
// KeyboardInteractiveCallback, if non-nil, is called when
// keyboard-interactive authentication is selected (RFC
// 4256). The client object's Challenge function should be
@@ -118,6 +158,12 @@ type ServerConfig struct {
// attempts.
AuthLogCallback func(conn ConnMetadata, method string, err error)
// PreAuthConnCallback, if non-nil, is called upon receiving a new connection
// before any authentication has started. The provided ServerPreAuthConn
// can be used at any time before authentication is complete, including
// after this callback has returned.
PreAuthConnCallback func(ServerPreAuthConn)
// ServerVersion is the version identification string to announce in
// the public handshake.
// If empty, a reasonable default is used.
@@ -149,7 +195,7 @@ func (s *ServerConfig) AddHostKey(key Signer) {
}
// cachedPubKey contains the results of querying whether a public key is
// acceptable for a user.
// acceptable for a user. This is a FIFO cache.
type cachedPubKey struct {
user string
pubKeyData []byte
@@ -157,7 +203,13 @@ type cachedPubKey struct {
perms *Permissions
}
const maxCachedPubKeys = 16
// maxCachedPubKeys is the number of cache entries we store.
//
// Due to consistent misuse of the PublicKeyCallback API, we have reduced this
// to 1, such that the only key in the cache is the most recently seen one. This
// forces the behavior that the last call to PublicKeyCallback will always be
// with the key that is used for authentication.
const maxCachedPubKeys = 1
// pubKeyCache caches tests for public keys. Since SSH clients
// will query whether a public key is acceptable before attempting to
@@ -179,9 +231,10 @@ func (c *pubKeyCache) get(user string, pubKeyData []byte) (cachedPubKey, bool) {
// add adds the given tuple to the cache.
func (c *pubKeyCache) add(candidate cachedPubKey) {
if len(c.keys) < maxCachedPubKeys {
c.keys = append(c.keys, candidate)
if len(c.keys) >= maxCachedPubKeys {
c.keys = c.keys[1:]
}
c.keys = append(c.keys, candidate)
}
// ServerConn is an authenticated SSH connection, as seen from the
@@ -209,22 +262,15 @@ func NewServerConn(c net.Conn, config *ServerConfig) (*ServerConn, <-chan NewCha
fullConf.MaxAuthTries = 6
}
if len(fullConf.PublicKeyAuthAlgorithms) == 0 {
fullConf.PublicKeyAuthAlgorithms = supportedPubKeyAuthAlgos
fullConf.PublicKeyAuthAlgorithms = defaultPubKeyAuthAlgos
} else {
for _, algo := range fullConf.PublicKeyAuthAlgorithms {
if !contains(supportedPubKeyAuthAlgos, algo) {
if !slices.Contains(SupportedAlgorithms().PublicKeyAuths, algo) && !slices.Contains(InsecureAlgorithms().PublicKeyAuths, algo) {
c.Close()
return nil, nil, nil, fmt.Errorf("ssh: unsupported public key authentication algorithm %s", algo)
}
}
}
// Check if the config contains any unsupported key exchanges
for _, kex := range fullConf.KeyExchanges {
if _, ok := serverForbiddenKexAlgos[kex]; ok {
c.Close()
return nil, nil, nil, fmt.Errorf("ssh: unsupported key exchange %s for server", kex)
}
}
s := &connection{
sshConn: sshConn{conn: c},
@@ -281,6 +327,7 @@ func (s *connection) serverHandshake(config *ServerConfig) (*Permissions, error)
// We just did the key change, so the session ID is established.
s.sessionID = s.transport.getSessionID()
s.algorithms = s.transport.getAlgorithms()
var packet []byte
if packet, err = s.transport.readPacket(); err != nil {
@@ -426,6 +473,35 @@ func (l ServerAuthError) Error() string {
return "[" + strings.Join(errs, ", ") + "]"
}
// ServerAuthCallbacks defines server-side authentication callbacks.
type ServerAuthCallbacks struct {
// PasswordCallback behaves like [ServerConfig.PasswordCallback].
PasswordCallback func(conn ConnMetadata, password []byte) (*Permissions, error)
// PublicKeyCallback behaves like [ServerConfig.PublicKeyCallback].
PublicKeyCallback func(conn ConnMetadata, key PublicKey) (*Permissions, error)
// KeyboardInteractiveCallback behaves like [ServerConfig.KeyboardInteractiveCallback].
KeyboardInteractiveCallback func(conn ConnMetadata, client KeyboardInteractiveChallenge) (*Permissions, error)
// GSSAPIWithMICConfig behaves like [ServerConfig.GSSAPIWithMICConfig].
GSSAPIWithMICConfig *GSSAPIWithMICConfig
}
// PartialSuccessError can be returned by any of the [ServerConfig]
// authentication callbacks to indicate to the client that authentication has
// partially succeeded, but further steps are required.
type PartialSuccessError struct {
// Next defines the authentication callbacks to apply to further steps. The
// available methods communicated to the client are based on the non-nil
// ServerAuthCallbacks fields.
Next ServerAuthCallbacks
}
func (p *PartialSuccessError) Error() string {
return "ssh: authenticated with partial success"
}
// ErrNoAuth is the error value returned if no
// authentication method has been passed yet. This happens as a normal
// part of the authentication loop, since the client first tries
@@ -433,14 +509,46 @@ func (l ServerAuthError) Error() string {
// It is returned in ServerAuthError.Errors from NewServerConn.
var ErrNoAuth = errors.New("ssh: no auth passed yet")
// BannerError is an error that can be returned by authentication handlers in
// ServerConfig to send a banner message to the client.
type BannerError struct {
Err error
Message string
}
func (b *BannerError) Unwrap() error {
return b.Err
}
func (b *BannerError) Error() string {
if b.Err == nil {
return b.Message
}
return b.Err.Error()
}
func (s *connection) serverAuthenticate(config *ServerConfig) (*Permissions, error) {
if config.PreAuthConnCallback != nil {
config.PreAuthConnCallback(s)
}
sessionID := s.transport.getSessionID()
var cache pubKeyCache
var perms *Permissions
authFailures := 0
noneAuthCount := 0
var authErrs []error
var displayedBanner bool
var calledBannerCallback bool
partialSuccessReturned := false
// Set the initial authentication callbacks from the config. They can be
// changed if a PartialSuccessError is returned.
authConfig := ServerAuthCallbacks{
PasswordCallback: config.PasswordCallback,
PublicKeyCallback: config.PublicKeyCallback,
KeyboardInteractiveCallback: config.KeyboardInteractiveCallback,
GSSAPIWithMICConfig: config.GSSAPIWithMICConfig,
}
userAuthLoop:
for {
@@ -453,8 +561,8 @@ userAuthLoop:
if err := s.transport.writePacket(Marshal(discMsg)); err != nil {
return nil, err
}
return nil, discMsg
authErrs = append(authErrs, discMsg)
return nil, &ServerAuthError{Errors: authErrs}
}
var userAuthReq userAuthRequestMsg
@@ -471,16 +579,17 @@ userAuthLoop:
return nil, errors.New("ssh: client attempted to negotiate for unknown service: " + userAuthReq.Service)
}
if s.user != userAuthReq.User && partialSuccessReturned {
return nil, fmt.Errorf("ssh: client changed the user after a partial success authentication, previous user %q, current user %q",
s.user, userAuthReq.User)
}
s.user = userAuthReq.User
if !displayedBanner && config.BannerCallback != nil {
displayedBanner = true
msg := config.BannerCallback(s)
if msg != "" {
bannerMsg := &userAuthBannerMsg{
Message: msg,
}
if err := s.transport.writePacket(Marshal(bannerMsg)); err != nil {
if !calledBannerCallback && config.BannerCallback != nil {
calledBannerCallback = true
if msg := config.BannerCallback(s); msg != "" {
if err := s.SendAuthBanner(msg); err != nil {
return nil, err
}
}
@@ -491,20 +600,18 @@ userAuthLoop:
switch userAuthReq.Method {
case "none":
if config.NoClientAuth {
noneAuthCount++
// We don't allow none authentication after a partial success
// response.
if config.NoClientAuth && !partialSuccessReturned {
if config.NoClientAuthCallback != nil {
perms, authErr = config.NoClientAuthCallback(s)
} else {
authErr = nil
}
}
// allow initial attempt of 'none' without penalty
if authFailures == 0 {
authFailures--
}
case "password":
if config.PasswordCallback == nil {
if authConfig.PasswordCallback == nil {
authErr = errors.New("ssh: password auth not configured")
break
}
@@ -518,17 +625,17 @@ userAuthLoop:
return nil, parseError(msgUserAuthRequest)
}
perms, authErr = config.PasswordCallback(s, password)
perms, authErr = authConfig.PasswordCallback(s, password)
case "keyboard-interactive":
if config.KeyboardInteractiveCallback == nil {
if authConfig.KeyboardInteractiveCallback == nil {
authErr = errors.New("ssh: keyboard-interactive auth not configured")
break
}
prompter := &sshClientKeyboardInteractive{s}
perms, authErr = config.KeyboardInteractiveCallback(s, prompter.Challenge)
perms, authErr = authConfig.KeyboardInteractiveCallback(s, prompter.Challenge)
case "publickey":
if config.PublicKeyCallback == nil {
if authConfig.PublicKeyCallback == nil {
authErr = errors.New("ssh: publickey auth not configured")
break
}
@@ -543,7 +650,7 @@ userAuthLoop:
return nil, parseError(msgUserAuthRequest)
}
algo := string(algoBytes)
if !contains(config.PublicKeyAuthAlgorithms, underlyingAlgo(algo)) {
if !slices.Contains(config.PublicKeyAuthAlgorithms, underlyingAlgo(algo)) {
authErr = fmt.Errorf("ssh: algorithm %q not accepted", algo)
break
}
@@ -562,11 +669,21 @@ userAuthLoop:
if !ok {
candidate.user = s.user
candidate.pubKeyData = pubKeyData
candidate.perms, candidate.result = config.PublicKeyCallback(s, pubKey)
if candidate.result == nil && candidate.perms != nil && candidate.perms.CriticalOptions != nil && candidate.perms.CriticalOptions[sourceAddressCriticalOption] != "" {
candidate.result = checkSourceAddress(
candidate.perms, candidate.result = authConfig.PublicKeyCallback(s, pubKey)
_, isPartialSuccessError := candidate.result.(*PartialSuccessError)
if isPartialSuccessError && config.VerifiedPublicKeyCallback != nil {
return nil, errors.New("ssh: invalid library usage: PublicKeyCallback must not return partial success when VerifiedPublicKeyCallback is defined")
}
if (candidate.result == nil || isPartialSuccessError) &&
candidate.perms != nil &&
candidate.perms.CriticalOptions != nil &&
candidate.perms.CriticalOptions[sourceAddressCriticalOption] != "" {
if err := checkSourceAddress(
s.RemoteAddr(),
candidate.perms.CriticalOptions[sourceAddressCriticalOption])
candidate.perms.CriticalOptions[sourceAddressCriticalOption]); err != nil {
candidate.result = err
}
}
cache.add(candidate)
}
@@ -578,8 +695,8 @@ userAuthLoop:
if len(payload) > 0 {
return nil, parseError(msgUserAuthRequest)
}
if candidate.result == nil {
_, isPartialSuccessError := candidate.result.(*PartialSuccessError)
if candidate.result == nil || isPartialSuccessError {
okMsg := userAuthPubKeyOkMsg{
Algo: algo,
PubKey: pubKeyData,
@@ -600,7 +717,7 @@ userAuthLoop:
// ssh-rsa-cert-v01@openssh.com algorithm with ssh-rsa public
// key type. The algorithm and public key type must be
// consistent: both must be certificate algorithms, or neither.
if !contains(algorithmsForKeyFormat(pubKey.Type()), algo) {
if !slices.Contains(algorithmsForKeyFormat(pubKey.Type()), algo) {
authErr = fmt.Errorf("ssh: public key type %q not compatible with selected algorithm %q",
pubKey.Type(), algo)
break
@@ -610,7 +727,7 @@ userAuthLoop:
// algorithm name that corresponds to algo with
// sig.Format. This is usually the same, but
// for certs, the names differ.
if !contains(config.PublicKeyAuthAlgorithms, sig.Format) {
if !slices.Contains(config.PublicKeyAuthAlgorithms, sig.Format) {
authErr = fmt.Errorf("ssh: algorithm %q not accepted", sig.Format)
break
}
@@ -627,13 +744,19 @@ userAuthLoop:
authErr = candidate.result
perms = candidate.perms
if authErr == nil && config.VerifiedPublicKeyCallback != nil {
// Only call VerifiedPublicKeyCallback after the key has been accepted
// and successfully verified. If authErr is non-nil, the key is not
// considered verified and the callback must not run.
perms, authErr = config.VerifiedPublicKeyCallback(s, pubKey, perms, algo)
}
}
case "gssapi-with-mic":
if config.GSSAPIWithMICConfig == nil {
if authConfig.GSSAPIWithMICConfig == nil {
authErr = errors.New("ssh: gssapi-with-mic auth not configured")
break
}
gssapiConfig := config.GSSAPIWithMICConfig
gssapiConfig := authConfig.GSSAPIWithMICConfig
userAuthRequestGSSAPI, err := parseGSSAPIPayload(userAuthReq.Payload)
if err != nil {
return nil, parseError(msgUserAuthRequest)
@@ -685,53 +808,83 @@ userAuthLoop:
config.AuthLogCallback(s, userAuthReq.Method, authErr)
}
var bannerErr *BannerError
if errors.As(authErr, &bannerErr) {
if bannerErr.Message != "" {
if err := s.SendAuthBanner(bannerErr.Message); err != nil {
return nil, err
}
}
}
if authErr == nil {
break 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 partialSuccess, ok := authErr.(*PartialSuccessError); ok {
// After a partial success error we don't allow changing the user
// name and execute the NoClientAuthCallback.
partialSuccessReturned = true
// In case a partial success is returned, the server may send
// a new set of authentication methods.
authConfig = partialSuccess.Next
// Reset pubkey cache, as the new PublicKeyCallback might
// accept a different set of public keys.
cache = pubKeyCache{}
// Send back a partial success message to the user.
failureMsg.PartialSuccess = true
} else {
// Allow initial attempt of 'none' without penalty.
if authFailures > 0 || userAuthReq.Method != "none" || noneAuthCount != 1 {
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 authentication 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 {
if authConfig.PasswordCallback != nil {
failureMsg.Methods = append(failureMsg.Methods, "password")
}
if config.PublicKeyCallback != nil {
if authConfig.PublicKeyCallback != nil {
failureMsg.Methods = append(failureMsg.Methods, "publickey")
}
if config.KeyboardInteractiveCallback != nil {
if authConfig.KeyboardInteractiveCallback != nil {
failureMsg.Methods = append(failureMsg.Methods, "keyboard-interactive")
}
if config.GSSAPIWithMICConfig != nil && config.GSSAPIWithMICConfig.Server != nil &&
config.GSSAPIWithMICConfig.AllowLogin != nil {
if authConfig.GSSAPIWithMICConfig != nil && authConfig.GSSAPIWithMICConfig.Server != nil &&
authConfig.GSSAPIWithMICConfig.AllowLogin != nil {
failureMsg.Methods = append(failureMsg.Methods, "gssapi-with-mic")
}
if len(failureMsg.Methods) == 0 {
return nil, errors.New("ssh: no authentication methods configured but NoClientAuth is also false")
return nil, errors.New("ssh: no authentication methods available")
}
if err := s.transport.writePacket(Marshal(&failureMsg)); err != nil {

View File

@@ -106,6 +106,13 @@ func parseGSSAPIPayload(payload []byte) (*userAuthRequestGSSAPI, error) {
if !ok {
return nil, errors.New("parse uint32 failed")
}
// Each ASN.1 encoded OID must have a minimum
// of 2 bytes; 64 maximum mechanisms is an
// arbitrary, but reasonable ceiling.
const maxMechs = 64
if n > maxMechs || int(n)*2 > len(rest) {
return nil, errors.New("invalid mechanism count")
}
s := &userAuthRequestGSSAPI{
N: n,
OIDS: make([]asn1.ObjectIdentifier, n),
@@ -122,7 +129,6 @@ func parseGSSAPIPayload(payload []byte) (*userAuthRequestGSSAPI, error) {
if rest, err = asn1.Unmarshal(desiredMech, &s.OIDS[i]); err != nil {
return nil, err
}
}
return s, nil
}

View File

@@ -44,7 +44,7 @@ func (c *Client) ListenUnix(socketPath string) (net.Listener, error) {
if !ok {
return nil, errors.New("ssh: streamlocal-forward@openssh.com request denied by peer")
}
ch := c.forwards.add(&net.UnixAddr{Name: socketPath, Net: "unix"})
ch := c.forwards.add("unix", socketPath)
return &unixListener{socketPath, c, ch}, nil
}
@@ -96,7 +96,7 @@ func (l *unixListener) Accept() (net.Conn, error) {
// Close closes the listener.
func (l *unixListener) Close() error {
// this also closes the listener.
l.conn.forwards.remove(&net.UnixAddr{Name: l.socketPath, Net: "unix"})
l.conn.forwards.remove("unix", l.socketPath)
m := streamLocalChannelForwardMsg{
l.socketPath,
}

View File

@@ -11,6 +11,7 @@ import (
"io"
"math/rand"
"net"
"net/netip"
"strconv"
"strings"
"sync"
@@ -22,14 +23,21 @@ import (
// the returned net.Listener. The listener must be serviced, or the
// SSH connection may hang.
// N must be "tcp", "tcp4", "tcp6", or "unix".
//
// If the address is a hostname, it is sent to the remote peer as-is, without
// being resolved locally, and the Listener Addr method will return a zero IP.
func (c *Client) Listen(n, addr string) (net.Listener, error) {
switch n {
case "tcp", "tcp4", "tcp6":
laddr, err := net.ResolveTCPAddr(n, addr)
host, portStr, err := net.SplitHostPort(addr)
if err != nil {
return nil, err
}
return c.ListenTCP(laddr)
port, err := strconv.ParseInt(portStr, 10, 32)
if err != nil {
return nil, err
}
return c.listenTCPInternal(host, int(port))
case "unix":
return c.ListenUnix(addr)
default:
@@ -102,15 +110,24 @@ func (c *Client) handleForwards() {
// ListenTCP requests the remote peer open a listening socket
// on laddr. Incoming connections will be available by calling
// Accept on the returned net.Listener.
//
// ListenTCP accepts an IP address, to provide a hostname use [Client.Listen]
// with "tcp", "tcp4", or "tcp6" network instead.
func (c *Client) ListenTCP(laddr *net.TCPAddr) (net.Listener, error) {
c.handleForwardsOnce.Do(c.handleForwards)
if laddr.Port == 0 && isBrokenOpenSSHVersion(string(c.ServerVersion())) {
return c.autoPortListenWorkaround(laddr)
}
return c.listenTCPInternal(laddr.IP.String(), laddr.Port)
}
func (c *Client) listenTCPInternal(host string, port int) (net.Listener, error) {
c.handleForwardsOnce.Do(c.handleForwards)
m := channelForwardMsg{
laddr.IP.String(),
uint32(laddr.Port),
host,
uint32(port),
}
// send message
ok, resp, err := c.SendRequest("tcpip-forward", true, Marshal(&m))
@@ -123,20 +140,33 @@ func (c *Client) ListenTCP(laddr *net.TCPAddr) (net.Listener, error) {
// If the original port was 0, then the remote side will
// supply a real port number in the response.
if laddr.Port == 0 {
if port == 0 {
var p struct {
Port uint32
}
if err := Unmarshal(resp, &p); err != nil {
return nil, err
}
laddr.Port = int(p.Port)
port = int(p.Port)
}
// Construct a local address placeholder for the remote listener. If the
// original host is an IP address, preserve it so that Listener.Addr()
// reports the same IP. If the host is a hostname or cannot be parsed as an
// IP, fall back to IPv4zero. The port field is always set, even if the
// original port was 0, because in that case the remote server will assign
// one, allowing callers to determine which port was selected.
ip := net.IPv4zero
if parsed, err := netip.ParseAddr(host); err == nil {
ip = net.IP(parsed.AsSlice())
}
laddr := &net.TCPAddr{
IP: ip,
Port: port,
}
addr := net.JoinHostPort(host, strconv.FormatInt(int64(port), 10))
ch := c.forwards.add("tcp", addr)
// Register this forward, using the port number we obtained.
ch := c.forwards.add(laddr)
return &tcpListener{laddr, c, ch}, nil
return &tcpListener{laddr, addr, c, ch}, nil
}
// forwardList stores a mapping between remote
@@ -149,8 +179,9 @@ type forwardList struct {
// forwardEntry represents an established mapping of a laddr on a
// remote ssh server to a channel connected to a tcpListener.
type forwardEntry struct {
laddr net.Addr
c chan forward
addr string // host:port or socket path
network string // tcp or unix
c chan forward
}
// forward represents an incoming forwarded tcpip connection. The
@@ -161,12 +192,13 @@ type forward struct {
raddr net.Addr // the raddr of the incoming connection
}
func (l *forwardList) add(addr net.Addr) chan forward {
func (l *forwardList) add(n, addr string) chan forward {
l.Lock()
defer l.Unlock()
f := forwardEntry{
laddr: addr,
c: make(chan forward, 1),
addr: addr,
network: n,
c: make(chan forward, 1),
}
l.entries = append(l.entries, f)
return f.c
@@ -185,19 +217,20 @@ func parseTCPAddr(addr string, port uint32) (*net.TCPAddr, error) {
if port == 0 || port > 65535 {
return nil, fmt.Errorf("ssh: port number out of range: %d", port)
}
ip := net.ParseIP(string(addr))
if ip == nil {
ip, err := netip.ParseAddr(addr)
if err != nil {
return nil, fmt.Errorf("ssh: cannot parse IP address %q", addr)
}
return &net.TCPAddr{IP: ip, Port: int(port)}, nil
return &net.TCPAddr{IP: net.IP(ip.AsSlice()), Port: int(port)}, nil
}
func (l *forwardList) handleChannels(in <-chan NewChannel) {
for ch := range in {
var (
laddr net.Addr
raddr net.Addr
err error
addr string
network string
raddr net.Addr
err error
)
switch channelType := ch.ChannelType(); channelType {
case "forwarded-tcpip":
@@ -207,40 +240,34 @@ func (l *forwardList) handleChannels(in <-chan NewChannel) {
continue
}
// RFC 4254 section 7.2 specifies that incoming
// addresses should list the address, in string
// format. It is implied that this should be an IP
// address, as it would be impossible to connect to it
// otherwise.
laddr, err = parseTCPAddr(payload.Addr, payload.Port)
if err != nil {
ch.Reject(ConnectionFailed, err.Error())
continue
}
// RFC 4254 section 7.2 specifies that incoming addresses should
// list the address that was connected, in string format. It is the
// same address used in the tcpip-forward request. The originator
// address is an IP address instead.
addr = net.JoinHostPort(payload.Addr, strconv.FormatUint(uint64(payload.Port), 10))
raddr, err = parseTCPAddr(payload.OriginAddr, payload.OriginPort)
if err != nil {
ch.Reject(ConnectionFailed, err.Error())
continue
}
network = "tcp"
case "forwarded-streamlocal@openssh.com":
var payload forwardedStreamLocalPayload
if err = Unmarshal(ch.ExtraData(), &payload); err != nil {
ch.Reject(ConnectionFailed, "could not parse forwarded-streamlocal@openssh.com payload: "+err.Error())
continue
}
laddr = &net.UnixAddr{
Name: payload.SocketPath,
Net: "unix",
}
addr = payload.SocketPath
raddr = &net.UnixAddr{
Name: "@",
Net: "unix",
}
network = "unix"
default:
panic(fmt.Errorf("ssh: unknown channel type %s", channelType))
}
if ok := l.forward(laddr, raddr, ch); !ok {
if ok := l.forward(network, addr, raddr, ch); !ok {
// Section 7.2, implementations MUST reject spurious incoming
// connections.
ch.Reject(Prohibited, "no forward for address")
@@ -252,11 +279,11 @@ func (l *forwardList) handleChannels(in <-chan NewChannel) {
// remove removes the forward entry, and the channel feeding its
// listener.
func (l *forwardList) remove(addr net.Addr) {
func (l *forwardList) remove(n, addr string) {
l.Lock()
defer l.Unlock()
for i, f := range l.entries {
if addr.Network() == f.laddr.Network() && addr.String() == f.laddr.String() {
if n == f.network && addr == f.addr {
l.entries = append(l.entries[:i], l.entries[i+1:]...)
close(f.c)
return
@@ -274,11 +301,11 @@ func (l *forwardList) closeAll() {
l.entries = nil
}
func (l *forwardList) forward(laddr, raddr net.Addr, ch NewChannel) bool {
func (l *forwardList) forward(n, addr string, raddr net.Addr, ch NewChannel) bool {
l.Lock()
defer l.Unlock()
for _, f := range l.entries {
if laddr.Network() == f.laddr.Network() && laddr.String() == f.laddr.String() {
if n == f.network && addr == f.addr {
f.c <- forward{newCh: ch, raddr: raddr}
return true
}
@@ -288,6 +315,7 @@ func (l *forwardList) forward(laddr, raddr net.Addr, ch NewChannel) bool {
type tcpListener struct {
laddr *net.TCPAddr
addr string
conn *Client
in <-chan forward
@@ -314,13 +342,21 @@ func (l *tcpListener) Accept() (net.Conn, error) {
// Close closes the listener.
func (l *tcpListener) Close() error {
host, port, err := net.SplitHostPort(l.addr)
if err != nil {
return err
}
rport, err := strconv.ParseUint(port, 10, 32)
if err != nil {
return err
}
m := channelForwardMsg{
l.laddr.IP.String(),
uint32(l.laddr.Port),
host,
uint32(rport),
}
// this also closes the listener.
l.conn.forwards.remove(l.laddr)
l.conn.forwards.remove("tcp", l.addr)
ok, _, err := l.conn.SendRequest("cancel-tcpip-forward", true, Marshal(&m))
if err == nil && !ok {
err = errors.New("ssh: cancel-tcpip-forward failed")
@@ -459,7 +495,7 @@ func (c *Client) dial(laddr string, lport int, raddr string, rport int) (Channel
return nil, err
}
go DiscardRequests(in)
return ch, err
return ch, nil
}
type tcpChan struct {

View File

@@ -8,6 +8,7 @@ import (
"bufio"
"bytes"
"errors"
"fmt"
"io"
"log"
)
@@ -16,13 +17,6 @@ import (
// wire. No message decoding is done, to minimize the impact on timing.
const debugTransport = false
const (
gcm128CipherID = "aes128-gcm@openssh.com"
gcm256CipherID = "aes256-gcm@openssh.com"
aes128cbcID = "aes128-cbc"
tripledescbcID = "3des-cbc"
)
// packetConn represents a transport that implements packet based
// operations.
type packetConn interface {
@@ -92,14 +86,14 @@ func (t *transport) setInitialKEXDone() {
// prepareKeyChange sets up key material for a keychange. The key changes in
// both directions are triggered by reading and writing a msgNewKey packet
// respectively.
func (t *transport) prepareKeyChange(algs *algorithms, kexResult *kexResult) error {
ciph, err := newPacketCipher(t.reader.dir, algs.r, kexResult)
func (t *transport) prepareKeyChange(algs *NegotiatedAlgorithms, kexResult *kexResult) error {
ciph, err := newPacketCipher(t.reader.dir, algs.Read, kexResult)
if err != nil {
return err
}
t.reader.pendingKeyChange <- ciph
ciph, err = newPacketCipher(t.writer.dir, algs.w, kexResult)
ciph, err = newPacketCipher(t.writer.dir, algs.Write, kexResult)
if err != nil {
return err
}
@@ -259,8 +253,11 @@ var (
// setupKeys sets the cipher and MAC keys from kex.K, kex.H and sessionId, as
// described in RFC 4253, section 6.4. direction should either be serverKeys
// (to setup server->client keys) or clientKeys (for client->server keys).
func newPacketCipher(d direction, algs directionAlgorithms, kex *kexResult) (packetCipher, error) {
func newPacketCipher(d direction, algs DirectionAlgorithms, kex *kexResult) (packetCipher, error) {
cipherMode := cipherModes[algs.Cipher]
if cipherMode == nil {
return nil, fmt.Errorf("ssh: unsupported cipher %v", algs.Cipher)
}
iv := make([]byte, cipherMode.ivSize)
key := make([]byte, cipherMode.keySize)