[cifs-protocol] [MS-CIFS] PendingRequestTable issues.
Christopher R. Hertel
crh at samba.org
Thu Mar 1 14:36:55 MST 2012
[Resending the message below due to a typo in the address.]
Dochelp,
In section 3.3.5.20 of [MS-CIFS] (Receiving an SMB_COM_PROCESS_EXIT
Request), there is the following statement:
The server MUST search the Server.Connection.PendingRequestTable for
any pending commands that have the same UID, TID, PID, and MID as
presented in the request. If the SMB transport is connectionless,
the header SID value SHOULD<264> also be used. For each matching
entry, the server MUST abort the pending operation. The client
process that made the aborted command request no longer exists to
receive the response.
There are two problems with the above statement.
1) For connectionless transports, you would use the CID value. The
CID is the Connection ID, used to identify a connection context
over a connectionless transport. The SID is a search ID.
2) The server must search the Server.Connection.PendingRequestTable
for *all* pending requests under the same PID. It is the PID
that is being closed. If you only look for those matching all
of [PID, MID, UID, TID], as presented in the Exit request, you
have the following problems:
* There is no SID value presented in the SMB_COM_PROCESS_EXIT,
but there is a CID in the header. More evidence that you
want CID not SID.
* No UID or TID are presented in the SMB_COM_PROCESS_EXIT
request, so you *cannot* match on those fields.
* The SMB_COM_PROCESS_EXIT is specific to a process, not a
MID within a process. A single process may use several MIDs
to identify threads within the process.
So, above should read:
The server MUST search the Server.Connection.PendingRequestTable for
any pending commands that have the same PID as presented in the
request header. If the SMB transport is connectionless, the header
CID value SHOULD<264> also be used. For each matching entry, the
server MUST abort the pending operation. The client process that
made the aborted command request no longer exists to receive the
response to the pending operations.
Please not that the SID->CID change also impacts Windows Behavior Note
<264>, which should read:
<264> Section 3.3.5.20: Windows NT Server 4.0 does not use the CID
as a lookup key. The list of pending requests is associated with
the SMB transport, so the effect is the same.
(That is, SID should be CID in that note. The note is otherwise correct.)
Chris -)-----
--
"Implementing CIFS - the Common Internet FileSystem" ISBN: 013047116X
Samba Team -- http://www.samba.org/ -)----- Christopher R. Hertel
jCIFS Team -- http://jcifs.samba.org/ -)----- ubiqx development, uninq.
ubiqx Team -- http://www.ubiqx.org/ -)----- crh at ubiqx.mn.org
OnLineBook -- http://ubiqx.org/cifs/ -)----- crh at ubiqx.org
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