On Wed, Jul 22, 2015 at 9:39 PM, Dave Garrett <[email protected]> wrote:
> Hubert Kairo found quite a few more spots in need of explicit error 
> designations, which have been amended into PR #201.
> https://github.com/tlswg/tls13-spec/pull/201
>
> I just noticed one error in the current draft text that was wrong and added a 
> fix for that as well. The Server Hello section said that lack of acceptable 
> group would result in an "insufficient_security" error, which is incorrect. 
> That error is clearly defined to be for lack of acceptable cipher suite. The 
> Negotiated Groups section says lack of acceptable group is a 
> “handshake_failure” error. I changed the text to state the error for suites, 
> as the other is already noted elsewhere. (this change is now in PR #201) This 
> brings up a problem, however: there is no distinct error for lack of group 
> support. The “handshake_failure” is a bit of a catchall, so there's no way 
> for a client to really know what's wrong if this happens. This is also why I 
> don't want to change the definition of the "insufficient_security" error. 
> Clients rely on these being relatively precise in order to show error 
> messages that are hopefully meaningful enough to get them fixed. As such, I'd 
> like to propose adding a new error just for this and renaming the old one to 
> focus precisely on its long defined meaning. While we're at it, a failure of 
> client authentication doesn't have its own error alert code either.
>
>   enum {
>        handshake_failure(40),
>        unsupported_cipher_suites(71),  /* formerly insufficient_security */
>        unsupported_dh_groups(72),  /* new */
>        client_authentication_failure(73),  /* new */
>        (255)
>    } AlertDescription;
>
> Pretty straightforward. Are there any other errors that can't be clearly 
> identified by the returned code? Debugging shouldn't be guesswork. ;)
>
Alert 40 shows up frequently in my debugging experiences. A few things
can cause it. It would be nice to see that one broken out.

Jeff

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