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path: root/vendor/golang.org/x/crypto/ssh/agent/server.go
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Diffstat (limited to 'vendor/golang.org/x/crypto/ssh/agent/server.go')
-rw-r--r--vendor/golang.org/x/crypto/ssh/agent/server.go570
1 files changed, 570 insertions, 0 deletions
diff --git a/vendor/golang.org/x/crypto/ssh/agent/server.go b/vendor/golang.org/x/crypto/ssh/agent/server.go
new file mode 100644
index 000000000..6e7a1e02f
--- /dev/null
+++ b/vendor/golang.org/x/crypto/ssh/agent/server.go
@@ -0,0 +1,570 @@
+// Copyright 2012 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 agent
+
+import (
+ "crypto/dsa"
+ "crypto/ecdsa"
+ "crypto/elliptic"
+ "crypto/rsa"
+ "encoding/binary"
+ "errors"
+ "fmt"
+ "io"
+ "log"
+ "math/big"
+
+ "golang.org/x/crypto/ed25519"
+ "golang.org/x/crypto/ssh"
+)
+
+// Server wraps an Agent and uses it to implement the agent side of
+// the SSH-agent, wire protocol.
+type server struct {
+ agent Agent
+}
+
+func (s *server) processRequestBytes(reqData []byte) []byte {
+ rep, err := s.processRequest(reqData)
+ if err != nil {
+ if err != errLocked {
+ // TODO(hanwen): provide better logging interface?
+ log.Printf("agent %d: %v", reqData[0], err)
+ }
+ return []byte{agentFailure}
+ }
+
+ if err == nil && rep == nil {
+ return []byte{agentSuccess}
+ }
+
+ return ssh.Marshal(rep)
+}
+
+func marshalKey(k *Key) []byte {
+ var record struct {
+ Blob []byte
+ Comment string
+ }
+ record.Blob = k.Marshal()
+ record.Comment = k.Comment
+
+ return ssh.Marshal(&record)
+}
+
+// See [PROTOCOL.agent], section 2.5.1.
+const agentV1IdentitiesAnswer = 2
+
+type agentV1IdentityMsg struct {
+ Numkeys uint32 `sshtype:"2"`
+}
+
+type agentRemoveIdentityMsg struct {
+ KeyBlob []byte `sshtype:"18"`
+}
+
+type agentLockMsg struct {
+ Passphrase []byte `sshtype:"22"`
+}
+
+type agentUnlockMsg struct {
+ Passphrase []byte `sshtype:"23"`
+}
+
+func (s *server) processRequest(data []byte) (interface{}, error) {
+ switch data[0] {
+ case agentRequestV1Identities:
+ return &agentV1IdentityMsg{0}, nil
+
+ case agentRemoveAllV1Identities:
+ return nil, nil
+
+ case agentRemoveIdentity:
+ var req agentRemoveIdentityMsg
+ if err := ssh.Unmarshal(data, &req); err != nil {
+ return nil, err
+ }
+
+ var wk wireKey
+ if err := ssh.Unmarshal(req.KeyBlob, &wk); err != nil {
+ return nil, err
+ }
+
+ return nil, s.agent.Remove(&Key{Format: wk.Format, Blob: req.KeyBlob})
+
+ case agentRemoveAllIdentities:
+ return nil, s.agent.RemoveAll()
+
+ case agentLock:
+ var req agentLockMsg
+ if err := ssh.Unmarshal(data, &req); err != nil {
+ return nil, err
+ }
+
+ return nil, s.agent.Lock(req.Passphrase)
+
+ case agentUnlock:
+ var req agentUnlockMsg
+ if err := ssh.Unmarshal(data, &req); err != nil {
+ return nil, err
+ }
+ return nil, s.agent.Unlock(req.Passphrase)
+
+ case agentSignRequest:
+ var req signRequestAgentMsg
+ if err := ssh.Unmarshal(data, &req); err != nil {
+ return nil, err
+ }
+
+ var wk wireKey
+ if err := ssh.Unmarshal(req.KeyBlob, &wk); err != nil {
+ return nil, err
+ }
+
+ k := &Key{
+ Format: wk.Format,
+ Blob: req.KeyBlob,
+ }
+
+ var sig *ssh.Signature
+ var err error
+ if extendedAgent, ok := s.agent.(ExtendedAgent); ok {
+ sig, err = extendedAgent.SignWithFlags(k, req.Data, SignatureFlags(req.Flags))
+ } else {
+ sig, err = s.agent.Sign(k, req.Data)
+ }
+
+ if err != nil {
+ return nil, err
+ }
+ return &signResponseAgentMsg{SigBlob: ssh.Marshal(sig)}, nil
+
+ case agentRequestIdentities:
+ keys, err := s.agent.List()
+ if err != nil {
+ return nil, err
+ }
+
+ rep := identitiesAnswerAgentMsg{
+ NumKeys: uint32(len(keys)),
+ }
+ for _, k := range keys {
+ rep.Keys = append(rep.Keys, marshalKey(k)...)
+ }
+ return rep, nil
+
+ case agentAddIDConstrained, agentAddIdentity:
+ return nil, s.insertIdentity(data)
+
+ case agentExtension:
+ // Return a stub object where the whole contents of the response gets marshaled.
+ var responseStub struct {
+ Rest []byte `ssh:"rest"`
+ }
+
+ if extendedAgent, ok := s.agent.(ExtendedAgent); !ok {
+ // If this agent doesn't implement extensions, [PROTOCOL.agent] section 4.7
+ // requires that we return a standard SSH_AGENT_FAILURE message.
+ responseStub.Rest = []byte{agentFailure}
+ } else {
+ var req extensionAgentMsg
+ if err := ssh.Unmarshal(data, &req); err != nil {
+ return nil, err
+ }
+ res, err := extendedAgent.Extension(req.ExtensionType, req.Contents)
+ if err != nil {
+ // If agent extensions are unsupported, return a standard SSH_AGENT_FAILURE
+ // message as required by [PROTOCOL.agent] section 4.7.
+ if err == ErrExtensionUnsupported {
+ responseStub.Rest = []byte{agentFailure}
+ } else {
+ // As the result of any other error processing an extension request,
+ // [PROTOCOL.agent] section 4.7 requires that we return a
+ // SSH_AGENT_EXTENSION_FAILURE code.
+ responseStub.Rest = []byte{agentExtensionFailure}
+ }
+ } else {
+ if len(res) == 0 {
+ return nil, nil
+ }
+ responseStub.Rest = res
+ }
+ }
+
+ return responseStub, nil
+ }
+
+ return nil, fmt.Errorf("unknown opcode %d", data[0])
+}
+
+func parseConstraints(constraints []byte) (lifetimeSecs uint32, confirmBeforeUse bool, extensions []ConstraintExtension, err error) {
+ for len(constraints) != 0 {
+ switch constraints[0] {
+ case agentConstrainLifetime:
+ lifetimeSecs = binary.BigEndian.Uint32(constraints[1:5])
+ constraints = constraints[5:]
+ case agentConstrainConfirm:
+ confirmBeforeUse = true
+ constraints = constraints[1:]
+ case agentConstrainExtension:
+ var msg constrainExtensionAgentMsg
+ if err = ssh.Unmarshal(constraints, &msg); err != nil {
+ return 0, false, nil, err
+ }
+ extensions = append(extensions, ConstraintExtension{
+ ExtensionName: msg.ExtensionName,
+ ExtensionDetails: msg.ExtensionDetails,
+ })
+ constraints = msg.Rest
+ default:
+ return 0, false, nil, fmt.Errorf("unknown constraint type: %d", constraints[0])
+ }
+ }
+ return
+}
+
+func setConstraints(key *AddedKey, constraintBytes []byte) error {
+ lifetimeSecs, confirmBeforeUse, constraintExtensions, err := parseConstraints(constraintBytes)
+ if err != nil {
+ return err
+ }
+
+ key.LifetimeSecs = lifetimeSecs
+ key.ConfirmBeforeUse = confirmBeforeUse
+ key.ConstraintExtensions = constraintExtensions
+ return nil
+}
+
+func parseRSAKey(req []byte) (*AddedKey, error) {
+ var k rsaKeyMsg
+ if err := ssh.Unmarshal(req, &k); err != nil {
+ return nil, err
+ }
+ if k.E.BitLen() > 30 {
+ return nil, errors.New("agent: RSA public exponent too large")
+ }
+ priv := &rsa.PrivateKey{
+ PublicKey: rsa.PublicKey{
+ E: int(k.E.Int64()),
+ N: k.N,
+ },
+ D: k.D,
+ Primes: []*big.Int{k.P, k.Q},
+ }
+ priv.Precompute()
+
+ addedKey := &AddedKey{PrivateKey: priv, Comment: k.Comments}
+ if err := setConstraints(addedKey, k.Constraints); err != nil {
+ return nil, err
+ }
+ return addedKey, nil
+}
+
+func parseEd25519Key(req []byte) (*AddedKey, error) {
+ var k ed25519KeyMsg
+ if err := ssh.Unmarshal(req, &k); err != nil {
+ return nil, err
+ }
+ priv := ed25519.PrivateKey(k.Priv)
+
+ addedKey := &AddedKey{PrivateKey: &priv, Comment: k.Comments}
+ if err := setConstraints(addedKey, k.Constraints); err != nil {
+ return nil, err
+ }
+ return addedKey, nil
+}
+
+func parseDSAKey(req []byte) (*AddedKey, error) {
+ var k dsaKeyMsg
+ if err := ssh.Unmarshal(req, &k); err != nil {
+ return nil, err
+ }
+ priv := &dsa.PrivateKey{
+ PublicKey: dsa.PublicKey{
+ Parameters: dsa.Parameters{
+ P: k.P,
+ Q: k.Q,
+ G: k.G,
+ },
+ Y: k.Y,
+ },
+ X: k.X,
+ }
+
+ addedKey := &AddedKey{PrivateKey: priv, Comment: k.Comments}
+ if err := setConstraints(addedKey, k.Constraints); err != nil {
+ return nil, err
+ }
+ return addedKey, nil
+}
+
+func unmarshalECDSA(curveName string, keyBytes []byte, privScalar *big.Int) (priv *ecdsa.PrivateKey, err error) {
+ priv = &ecdsa.PrivateKey{
+ D: privScalar,
+ }
+
+ switch curveName {
+ case "nistp256":
+ priv.Curve = elliptic.P256()
+ case "nistp384":
+ priv.Curve = elliptic.P384()
+ case "nistp521":
+ priv.Curve = elliptic.P521()
+ default:
+ return nil, fmt.Errorf("agent: unknown curve %q", curveName)
+ }
+
+ priv.X, priv.Y = elliptic.Unmarshal(priv.Curve, keyBytes)
+ if priv.X == nil || priv.Y == nil {
+ return nil, errors.New("agent: point not on curve")
+ }
+
+ return priv, nil
+}
+
+func parseEd25519Cert(req []byte) (*AddedKey, error) {
+ var k ed25519CertMsg
+ if err := ssh.Unmarshal(req, &k); err != nil {
+ return nil, err
+ }
+ pubKey, err := ssh.ParsePublicKey(k.CertBytes)
+ if err != nil {
+ return nil, err
+ }
+ priv := ed25519.PrivateKey(k.Priv)
+ cert, ok := pubKey.(*ssh.Certificate)
+ if !ok {
+ return nil, errors.New("agent: bad ED25519 certificate")
+ }
+
+ addedKey := &AddedKey{PrivateKey: &priv, Certificate: cert, Comment: k.Comments}
+ if err := setConstraints(addedKey, k.Constraints); err != nil {
+ return nil, err
+ }
+ return addedKey, nil
+}
+
+func parseECDSAKey(req []byte) (*AddedKey, error) {
+ var k ecdsaKeyMsg
+ if err := ssh.Unmarshal(req, &k); err != nil {
+ return nil, err
+ }
+
+ priv, err := unmarshalECDSA(k.Curve, k.KeyBytes, k.D)
+ if err != nil {
+ return nil, err
+ }
+
+ addedKey := &AddedKey{PrivateKey: priv, Comment: k.Comments}
+ if err := setConstraints(addedKey, k.Constraints); err != nil {
+ return nil, err
+ }
+ return addedKey, nil
+}
+
+func parseRSACert(req []byte) (*AddedKey, error) {
+ var k rsaCertMsg
+ if err := ssh.Unmarshal(req, &k); err != nil {
+ return nil, err
+ }
+
+ pubKey, err := ssh.ParsePublicKey(k.CertBytes)
+ if err != nil {
+ return nil, err
+ }
+
+ cert, ok := pubKey.(*ssh.Certificate)
+ if !ok {
+ return nil, errors.New("agent: bad RSA certificate")
+ }
+
+ // An RSA publickey as marshaled by rsaPublicKey.Marshal() in keys.go
+ var rsaPub struct {
+ Name string
+ E *big.Int
+ N *big.Int
+ }
+ if err := ssh.Unmarshal(cert.Key.Marshal(), &rsaPub); err != nil {
+ return nil, fmt.Errorf("agent: Unmarshal failed to parse public key: %v", err)
+ }
+
+ if rsaPub.E.BitLen() > 30 {
+ return nil, errors.New("agent: RSA public exponent too large")
+ }
+
+ priv := rsa.PrivateKey{
+ PublicKey: rsa.PublicKey{
+ E: int(rsaPub.E.Int64()),
+ N: rsaPub.N,
+ },
+ D: k.D,
+ Primes: []*big.Int{k.Q, k.P},
+ }
+ priv.Precompute()
+
+ addedKey := &AddedKey{PrivateKey: &priv, Certificate: cert, Comment: k.Comments}
+ if err := setConstraints(addedKey, k.Constraints); err != nil {
+ return nil, err
+ }
+ return addedKey, nil
+}
+
+func parseDSACert(req []byte) (*AddedKey, error) {
+ var k dsaCertMsg
+ if err := ssh.Unmarshal(req, &k); err != nil {
+ return nil, err
+ }
+ pubKey, err := ssh.ParsePublicKey(k.CertBytes)
+ if err != nil {
+ return nil, err
+ }
+ cert, ok := pubKey.(*ssh.Certificate)
+ if !ok {
+ return nil, errors.New("agent: bad DSA certificate")
+ }
+
+ // A DSA publickey as marshaled by dsaPublicKey.Marshal() in keys.go
+ var w struct {
+ Name string
+ P, Q, G, Y *big.Int
+ }
+ if err := ssh.Unmarshal(cert.Key.Marshal(), &w); err != nil {
+ return nil, fmt.Errorf("agent: Unmarshal failed to parse public key: %v", err)
+ }
+
+ priv := &dsa.PrivateKey{
+ PublicKey: dsa.PublicKey{
+ Parameters: dsa.Parameters{
+ P: w.P,
+ Q: w.Q,
+ G: w.G,
+ },
+ Y: w.Y,
+ },
+ X: k.X,
+ }
+
+ addedKey := &AddedKey{PrivateKey: priv, Certificate: cert, Comment: k.Comments}
+ if err := setConstraints(addedKey, k.Constraints); err != nil {
+ return nil, err
+ }
+ return addedKey, nil
+}
+
+func parseECDSACert(req []byte) (*AddedKey, error) {
+ var k ecdsaCertMsg
+ if err := ssh.Unmarshal(req, &k); err != nil {
+ return nil, err
+ }
+
+ pubKey, err := ssh.ParsePublicKey(k.CertBytes)
+ if err != nil {
+ return nil, err
+ }
+ cert, ok := pubKey.(*ssh.Certificate)
+ if !ok {
+ return nil, errors.New("agent: bad ECDSA certificate")
+ }
+
+ // An ECDSA publickey as marshaled by ecdsaPublicKey.Marshal() in keys.go
+ var ecdsaPub struct {
+ Name string
+ ID string
+ Key []byte
+ }
+ if err := ssh.Unmarshal(cert.Key.Marshal(), &ecdsaPub); err != nil {
+ return nil, err
+ }
+
+ priv, err := unmarshalECDSA(ecdsaPub.ID, ecdsaPub.Key, k.D)
+ if err != nil {
+ return nil, err
+ }
+
+ addedKey := &AddedKey{PrivateKey: priv, Certificate: cert, Comment: k.Comments}
+ if err := setConstraints(addedKey, k.Constraints); err != nil {
+ return nil, err
+ }
+ return addedKey, nil
+}
+
+func (s *server) insertIdentity(req []byte) error {
+ var record struct {
+ Type string `sshtype:"17|25"`
+ Rest []byte `ssh:"rest"`
+ }
+
+ if err := ssh.Unmarshal(req, &record); err != nil {
+ return err
+ }
+
+ var addedKey *AddedKey
+ var err error
+
+ switch record.Type {
+ case ssh.KeyAlgoRSA:
+ addedKey, err = parseRSAKey(req)
+ case ssh.KeyAlgoDSA:
+ addedKey, err = parseDSAKey(req)
+ case ssh.KeyAlgoECDSA256, ssh.KeyAlgoECDSA384, ssh.KeyAlgoECDSA521:
+ addedKey, err = parseECDSAKey(req)
+ case ssh.KeyAlgoED25519:
+ addedKey, err = parseEd25519Key(req)
+ case ssh.CertAlgoRSAv01:
+ addedKey, err = parseRSACert(req)
+ case ssh.CertAlgoDSAv01:
+ addedKey, err = parseDSACert(req)
+ case ssh.CertAlgoECDSA256v01, ssh.CertAlgoECDSA384v01, ssh.CertAlgoECDSA521v01:
+ addedKey, err = parseECDSACert(req)
+ case ssh.CertAlgoED25519v01:
+ addedKey, err = parseEd25519Cert(req)
+ default:
+ return fmt.Errorf("agent: not implemented: %q", record.Type)
+ }
+
+ if err != nil {
+ return err
+ }
+ return s.agent.Add(*addedKey)
+}
+
+// ServeAgent serves the agent protocol on the given connection. It
+// returns when an I/O error occurs.
+func ServeAgent(agent Agent, c io.ReadWriter) error {
+ s := &server{agent}
+
+ var length [4]byte
+ for {
+ if _, err := io.ReadFull(c, length[:]); err != nil {
+ return err
+ }
+ l := binary.BigEndian.Uint32(length[:])
+ if l == 0 {
+ return fmt.Errorf("agent: request size is 0")
+ }
+ if l > maxAgentResponseBytes {
+ // We also cap requests.
+ return fmt.Errorf("agent: request too large: %d", l)
+ }
+
+ req := make([]byte, l)
+ if _, err := io.ReadFull(c, req); err != nil {
+ return err
+ }
+
+ repData := s.processRequestBytes(req)
+ if len(repData) > maxAgentResponseBytes {
+ return fmt.Errorf("agent: reply too large: %d bytes", len(repData))
+ }
+
+ binary.BigEndian.PutUint32(length[:], uint32(len(repData)))
+ if _, err := c.Write(length[:]); err != nil {
+ return err
+ }
+ if _, err := c.Write(repData); err != nil {
+ return err
+ }
+ }
+}
generated by cgit v1.2.3-54-g00ecf (git 2.39.0) at 2024-11-12 07:19:04 +0000