func parseKey(in []byte) (out *Key, rest []byte, err error) {
var record struct {
Blob []byte
Comment string
Rest []byte `ssh:"rest"`
}
if err := ssh.Unmarshal(in, &record); err != nil {
return nil, nil, err
}
var wk wireKey
if err := ssh.Unmarshal(record.Blob, &wk); err != nil {
return nil, nil, err
}
return &Key{
Format: wk.Format,
Blob: record.Blob,
Comment: record.Comment,
}, record.Rest, nil
}
// unmarshal parses an agent message in packet, returning the parsed
// form and the message type of packet.
func unmarshal(packet []byte) (interface{}, error) {
if len(packet) < 1 {
return nil, errors.New("agent: empty packet")
}
var msg interface{}
switch packet[0] {
case agentFailure:
return new(failureAgentMsg), nil
case agentSuccess:
return new(successAgentMsg), nil
case agentIdentitiesAnswer:
msg = new(identitiesAnswerAgentMsg)
case agentSignResponse:
msg = new(signResponseAgentMsg)
default:
return nil, fmt.Errorf("agent: unknown type tag %d", packet[0])
}
if err := ssh.Unmarshal(packet, msg); err != nil {
return nil, err
}
return msg, nil
}
// Sign has the agent sign the data using a protocol 2 key as defined
// in [PROTOCOL.agent] section 2.6.2.
func (c *client) Sign(key ssh.PublicKey, data []byte) (*ssh.Signature, error) {
req := ssh.Marshal(signRequestAgentMsg{
KeyBlob: key.Marshal(),
Data: data,
})
msg, err := c.call(req)
if err != nil {
return nil, err
}
switch msg := msg.(type) {
case *signResponseAgentMsg:
var sig ssh.Signature
if err := ssh.Unmarshal(msg.SigBlob, &sig); err != nil {
return nil, err
}
return &sig, nil
case *failureAgentMsg:
return nil, errors.New("agent: failed to sign challenge")
}
panic("unreachable")
}