s4:rpc_server/dcesrv_auth.c - Fix a RPC issue in conjunction with Windows 2000

Andrew Bartlett abartlet at samba.org
Sun May 30 07:36:05 MDT 2010

On Sun, 2010-05-30 at 15:29 +0200, Stefan (metze) Metzmacher wrote:
> Am 30.05.2010 15:20, schrieb Stefan (metze) Metzmacher:
> > Hi Matthias,
> > 
> >> if you are so concerned I don't have another possibility other than to
> >> revert it. I just would like to bring to attention that the mentioned
> >> "special" RPC calls work against Windows Server 2008 - so the problem is
> >> definitely valid.
> >> Before I pushed this fix I tried also to activate our header-sign
> >> support ("dcesrv:header sign = yes" in smb.conf) - which would be the
> >> expected solution. But then the whole schannel interactions with the
> >> Windows client broke.
> > 
> > We don't support header signing for all auth types yet, but also don't
> > have to, as the client won't use it, if the server doesn't indicate
> > support for it.
> > 
> >> I revert but I wish that you or metze take care about the issue and see
> >> what's still missing in our own RPC header-sign implementation. If this
> >> is fixed then we are done.
> > 
> > I'm sure we'll fix this problem, but I'm not sure that it's related to
> > header signing
> > at all.
> > 
> > We need a torture test that does the packet sequence as a windows 2000
> > client
> > first (with all the same bits set).
> I think the correct fix should be in
> schannel_session_info(), there we force auth_anonymous_session_info()
> which seems to be wrong. We should not provide a session_info at all,
> to indicate to the dcerpc server code that it should keep the transport
> related
> session info.
> metze

Yeah, that may be the correct fix.  Fortunately we can tell, as we can
ask the LSA server for our username, and we can try different
combinations, once we get the handle via the exact sequence used by
Windows 2000. 

I previously had this code use the machine account, but that didn't
match what RPC-SCHANNEL showed windows did. 

Andrew Bartlett

Andrew Bartlett                                http://samba.org/~abartlet/
Authentication Developer, Samba Team           http://samba.org
Samba Developer, Cisco Inc.
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