Re: GSSAPI and V2 protocol - Mailing list pgsql-hackers

From Magnus Hagander
Subject Re: GSSAPI and V2 protocol
Date
Msg-id 20080206113229.GE4714@svr2.hagander.net
Whole thread Raw
In response to Re: GSSAPI and V2 protocol  (Kris Jurka <books@ejurka.com>)
Responses Re: GSSAPI and V2 protocol  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
On Wed, Feb 06, 2008 at 02:57:39AM -0500, Kris Jurka wrote:
> 
> 
> On Tue, 5 Feb 2008, Tom Lane wrote:
> 
> >The problem seems to be that AuthenticationGSSContinue messages carry
> >a variable-length payload, and the V2 protocol doesn't really cope with
> >that because it doesn't have a message length word.
> >
> >1. If the GSSContinue payload is self-identifying about its length,
> >qwe could teach fe-connect.c how to determine that.
> 
> The GSS data is supposed to be opaque to the caller, so this doesn't 
> seem likely or a good idea.

Yeah, agreed, that seems like a very fragile idea. 


> >2. We could retroactively redefine the contents of
> >AuthenticationGSSContinue as carrying a length word after the
> >authentication type code, but only in V2 protocol (so as not to break
> >existing working cases).  This is pretty ugly but certainly possible.
> 
> I see no harm in doing this.  What's there now can't work and the change 
> is self contained.  Is there any problem with the password message taking 
> a "String" datatype instead of Byte[n] with a null byte?

I agree that this is probabliy the best way, if we can do it. But you do
raise a good point - the message that goes the other way can certainly contain
embedded NULLs. 

//Magnus


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