Hi Bill,
I have done some more investigation on this issue, particularly around
doing a Trans2SetPathInfo() with the documented
FileEndOfFileInformation (0x104) level. It returns what I would
expect to be an acceptable error for an unknown info level. I have
attached a trace that shows this being done against a win7 server, but
I have a question about what the server is returning. The packets of
interest are 39/40:
1. Packet 40 appears to have the WordCount and ByteCount truncated,
making the packet smaller than normal minimum size of 35? Is this
intended behavior that other servers should implement?
Additionally a DOS Error is returned instead of a standard NT_STATUS
error. MS-CIFS does say that a DOS error or an NT_STATUS error may be
returned, but I don't see any indication in the documentation of when
a DOS error should be returned instead of an NT_STATUS error. Is it
possible to make this explicit in the docs or is this a case where
it's purposefully left ambiguous?
Thanks!
-Tim
On Nov 25, 2009, at 11:13 AM, Bill Wesse wrote:
Question:
Which existing handle would the pass-through be using? The handle
opened in packet #28 is a separate tcp connection and a separte
session from the Trans2SetPathInfo in packet #33. I'm not aware of
any situation where the server is expected to share file handles
across multiple sessions. Is this an exception?
Response:
I was paying more attention to the PID (0x26CD) - and didn't drill
down closer to the sessions (both of which use the same security
principal). Thanks for pointing that out; I will take it into
account during my ongoing study (this implies a straight share mode
bypass).
Question:
If a client can send a particular info level and windows implements
it, then we have a compatibility problem if we choose not to support
it. What I would really like to know is if other SMB implementations
need to circumvent share-mode checks for this pass through level (and
maybe others?).
Response:
That is certainly one of my goals - as I noted in my recent response
to Jeremy, I intend to set up test code to exercise the information
levels against the SMB calls.
As I also mentioned, I will submit a TDI against this - before
starting on any test code.
Also, the best reference for the full roster of info levels is at:
MSDN WDF_FILE_INFORMATION_CLASS
http://msdn.microsoft.com/en-us/library/dd568296.aspx
this being a subset:
[MS-FSCC] 2.4 File Information Classes
http://msdn.microsoft.com/en-us/library/cc232064.aspx
Regards,
Bill Wesse
MCSE, MCTS / Senior Escalation Engineer, US-CSS DSC PROTOCOL TEAM
8055 Microsoft Way
Charlotte, NC 28273
TEL: +1(980) 776-8200
CELL: +1(704) 661-5438
FAX: +1(704) 665-9606
-----Original Message-----
From: Tim Prouty [mailto:tim.pro...@isilon.com]
Sent: Wednesday, November 25, 2009 1:21 PM
To: Bill Wesse
Cc: cifs-proto...@samba.org; p...@tridgell.net
Subject: Re: SMB1 Trans2SetPathInfo() FileEndOfFileInformation is
not enforcing share modes
Hi Bill,
Thank you for the quick answer! I have a few comments/questions
below.
On Nov 25, 2009, at 9:14 AM, Bill Wesse wrote:
Hello Tim. I think the difference in the response between the
standard versus pass-through level lies in how the file handle is
obtained during the call (given that TRANS2_SET_PATH_INFORMATION
passes the path, and not the handle). The logical conclusion from
the trace is that pass-through gets the existing handle, and the non
pass-through value simply fails, because a new handle cannot be
opened due to the lack of sharing.
Which existing handle would the pass-through be using? The handle
opened in packet #28 is a separate tcp connection and a separte
session from the Trans2SetPathInfo in packet #33. I'm not aware of
any situation where the server is expected to share file handles
across multiple sessions. Is this an exception?
I will continue my investigation into the details on the differences
between the base & pass-through handling, with respect to the file
path / handle source. Pass-through is basically implementation
dependent, as noted in [MS-FSCC] (reference below), so there is a
possibility this may not be further elaborated on in the documents.
If a client can send a particular info level and windows implements
it, then we have a compatibility problem if we choose not to support
it. What I would really like to know is if other SMB implementations
need to circumvent share-mode checks for this pass through level (and
maybe others?).
Of course, TRANS2_SET_FILE_INFORMATION should succeed (without a
pass-through value), since that requires the file handle (per [MS-
CIFS] 2.2.6.9 TRANS2_SET_FILE_INFORMATION (0x0008) at
http://msdn.microsoft.com/en-us/library/ee442064.aspx)
.
I agree. A Trans2SetFileInfo on the fid opened in packet #28 from the
same session would have succeeded.
-Tim
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