Implement ExtendedAgent

Allows clients to specify the algorithm used via the `SignWithFlags` function. Currently this is `rsa-sha2-256` or `rsa-sha2-512` which are the two allowable options in the spec but it is extendable in the future as required.

Aiming to reduce code duplication, Existing `Sign` function retains it's default behaviour by calling `SignWithFlags` with `SignatureFlagReserved`.

The other `ExtendedAgent` function `Extension` returns `ErrExtensionUnsupported` to all calls as required by the spec.
This commit is contained in:
Chris Sutcliff 2024-02-23 11:09:38 +00:00
parent 8553e0d798
commit c7cc1d646e
No known key found for this signature in database

View File

@ -81,6 +81,10 @@ func Eq(a, b ssh.PublicKey) bool {
}
func (vaultAgent vaultAgent) Sign(key ssh.PublicKey, data []byte) (*ssh.Signature, error) {
return vaultAgent.SignWithFlags(key, data, agent.SignatureFlagReserved)
}
func (vaultAgent vaultAgent) SignWithFlags(key ssh.PublicKey, data []byte, flags agent.SignatureFlags) (*ssh.Signature, error) {
log.Info("Sign Request for key: %s", ssh.FingerprintSHA256(key))
if vaultAgent.vault.Keyring.IsLocked() {
if !vaultAgent.unlockRequestAction() {
@ -156,7 +160,30 @@ func (vaultAgent vaultAgent) Sign(key ssh.PublicKey, data []byte) (*ssh.Signatur
} else {
notify.Notify("Goldwarden", fmt.Sprintf("SSH Signing Request Approved for %s", sshKey.Name), "", 10*time.Second, func() {})
}
return signer.Sign(rand, data)
algo := ""
switch flags {
case agent.SignatureFlagRsaSha256:
algo = ssh.KeyAlgoRSASHA256
case agent.SignatureFlagRsaSha512:
algo = ssh.KeyAlgoRSASHA512
default:
return signer.Sign(rand, data)
}
log.Info("%s algorithm requested", algo)
algoSigner, err := ssh.NewSignerWithAlgorithms(signer.(ssh.AlgorithmSigner), []string{algo})
if err != nil {
return nil, err
}
return algoSigner.SignWithAlgorithm(rand, data, algo)
}
func (vaultAgent) Extension(extensionType string, contents []byte) ([]byte, error) {
return nil, agent.ErrExtensionUnsupported
}
func (vaultAgent) Signers() ([]ssh.Signer, error) {