psanford / ctapkey Goto Github PK

There is a check that the Auth Ctrl value is known both here in the decoding: https://github.com/psanford/ctapkey/blob/main/u2f/u2f.go#L79 and here in handleAuthenticate: https://github.com/psanford/ctapkey/blob/main/ctapkey.go#L130

The latter will never happen, because decoding the auth req would fail. The former check does not do any WriteResponse, but the latter would. Wondering if this is fine -- not responding if the Auth Ctrl is unknown. Because that's how the code currently behaves. If so, the check in handleAuthenticate should probably just be removed.

Perhaps I have not gotten the overall gist of the U2F protocol, and a response is not really expected -- it is rather up to the FIDO client to do retries/timeouts. It does feel like that from reading your implementation, as you don't do any WriteResponse on several occasions of errors. Because, yeah, there would not even be any really suitable response code (there are not many of them either).