On Wed, Jan 19, 2011 at 6:55 PM, Saúl Ibarra Corretgé <saghul@gmail.com> wrote:
Hi all,
I'm experiencing something weird while writing a simple SSH server, and I wonder if anyone did run into this before:
On every snippet I see around regarding public key authentication, the signature is checked as follows:
# if not credentials.signature: # return failure.Failure(ValidPublicKey()) # try: # public_key = keys.Key.fromString(data=credentials.blob) # except (keys.BadKeyError, keys.EncryptedKeyError): # return failure.Failure(ConchError("Public key error"))
If it's not continuing, that's a problem with the other side. What happens with the SSH protocol is: C: sends a message asking 'if this public key okay?' without sending any signed data S: says either "no it's not valid for this account" or "yes it is valid, please prove you have the private key" C: if yes, sign some data and send the signature; otherwise try a different key or different authentication mechanism The 'if not credentials.signature: return failure.Failure(ValidPublicKey())' code is how the server tells the client it's a valid key, but needs to prove it also has the public key. -p -- Paul Swartz paulswartz at gmail dot com http://paulswartz.net/ AIM: z3penguin