[PATCH] s3-winbindd: Store schannel credentials in secrets.tdb

Andrew Bartlett abartlet at samba.org
Thu Oct 4 17:08:24 MDT 2012

On Thu, 2012-10-04 at 15:56 -0700, Christof Schmitt wrote:
> Andrew Bartlett <abartlet at samba.org> wrote on 10/03/2012 06:46:54 PM:
> > However you do it, you do need to serialise the sequence number updates
> > for send, but a restructure may avoid you needing to serialise the whole
> > request/reply chain.  Essentially, we both probably need to read up the
> > docs, and see if instead we can store an expected reply for a given
> > sequence number.  That would avoid needing to lock over the network ops
> > waiting for the reply. 
> I started looking into this part and reading MS-NRPC. Using the lock
> only for sending the request would mean using the async calls
> dcerpc_netr_LogonSamLogon_send() and dcerpc_netr_LogonSamLogon_recv()
> instead of the sync one dcerpc_netr_LogonSamLogon().
> netlogon_creds_client_check() is simply a memcmp(), so the client
> already has the expected reply for verifying the server response.
> Besides LogonSamLogon, the same changes have to be made for all calls
> using the struct netr_Authenticator.
> Looking at the code, source3/rpc_client/cli_netlogon.c might be a good
> place to make those changes. Maybe this file would be also a better
> place to access the schannel tdb.
> I will continue from here, just let me know in case i am heading in
> the wrong direction.

Even better would be a set of generic, async wrappers around the
dcerpc_netr_LogonSamLogon_send() and dcerpc_netr_LogonSamLogon_recv()
(et al) calls that fills in the authenticator on the way out, and check
it on the way back. 

We are trying to push the async layer up the stack as far as possible,
so it would be best if new code didn't make that harder.  (Particularly
for crypto code, which few dare to touch once implemented :-)

Andrew Bartlett

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

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