mirror of
https://github.com/42wim/matterbridge.git
synced 2024-12-26 21:22:35 +01:00
524 lines
12 KiB
Go
524 lines
12 KiB
Go
// 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,
|
|
}
|
|
|
|
sig, err := s.agent.Sign(k, req.Data) // TODO(hanwen): flags.
|
|
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)
|
|
}
|
|
|
|
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 > 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
|
|
}
|
|
}
|
|
}
|