fix crash with missing mechtypes

[simo]

On Sat, 2010-09-25 at 08:31 +1000, Andrew Bartlett wrote:
> On Fri, 2010-09-24 at 09:57 -0700, Jeremy Allison wrote:
> > On Fri, Sep 24, 2010 at 12:36:37PM -0400, simo wrote:
> > > 
> > > Do you know how windows behaves against the same test ?
> > 
> > No, the test suites are proprietary and even if I did
> > I couldn't discuss it (under plugfest NDA I'm afraid).
> 
> http://tools.ietf.org/html/rfc4178#section-4.2.1
> I decided to look up the RFC: 
> 
> 4.2.1.  negTokenInit
> 
>       NegTokenInit ::= SEQUENCE {
>           mechTypes       [0] MechTypeList,
>           reqFlags        [1] ContextFlags  OPTIONAL,
>             -- inherited from RFC 2478 for backward compatibility,
>             -- RECOMMENDED to be left out
>           mechToken       [2] OCTET STRING  OPTIONAL,
>           mechListMIC     [3] OCTET STRING  OPTIONAL,
>           ...
>       }
>       ContextFlags ::= BIT STRING {
>           delegFlag       (0),
>           mutualFlag      (1),
>           replayFlag      (2),
>           sequenceFlag    (3),
>           anonFlag        (4),
>           confFlag        (5),
>           integFlag       (6)
>       } (SIZE (32))
> 
>    This is the syntax for the inner token of the initial negotiation
>    message.
> 
>    mechTypes
> 
>       This field contains one or more security mechanisms available for
>       the initiator, in decreasing preference order (favorite choice
>       first).
> 
> The older http://tools.ietf.org/html/rfc2478 also states that one or
> more mechTypes must be sent, but marks the ASN.1 as optional. 
> 
> > This fix prevents the crash, and I still think not
> > sending any OID's in a packet is definitely an invalid
> > parameter error :-).
> 
> It seems to me that this isn't optional, and therefore an invalid
> parameter reply is quite justified.

Ok, then all is fine, indeed.

Simo.

-- 
Simo Sorce
Samba Team GPL Compliance Officer <simo at samba.org>
Principal Software Engineer at Red Hat, Inc. <simo at redhat.com>