Re: [xmpp] SASL errors in 3920bis-03

[Alexey Melnikov <alexey.melnikov at isode.com>]

Tobias Markmann wrote:
> Hi,
Hi Tobias,
> According to 3920bis-03 there are this two errors defined: 
> mechanism-invalid [1] and mechanism-too-weak [2]. I think 
> mechanism-invalid would be sufficient.
>
> SASL usually works the way that first the server advertises what it 
> supports and then the client gets to choose. A client selecting a 
> mechanism which hasn't advertised is quite broken in my opinion.
I agree.
But there might be another use case for the error code - selection of a 
mechanism which is considered too weak for a particular user. In such 
case the server would advertise the mechanism to everybody, but return 
the error for some users.
> Since it's broken why have two errors for this. I mean the client 
> can't really do something useful with the info mechanism-too-weak. 
> Selecting and unsupported mechanism is quite a bug and I think it 
> would be cleaner to not split our errors in areas that are about buggy 
> clients. Or have I missed the clients that bring up a text box where 
> the user can enter the mechanism to use manually? ;)
>
> Cheers,
> Tobias
>
> [1] http://tools.ietf.org/html/draft-ietf-xmpp-3920bis-03#section-7.4.7
> [2] http://tools.ietf.org/html/draft-ietf-xmpp-3920bis-03#section-7.4.9