MRXSMB returns STATUS_INVALID_PARAMETER

NTFSD
1

I am trying to understand why MRXSMB on Windows XP sometimes returns
STATUS_INVALID_PARAMETER when enabling files for offline synchronization.

I found out that MRxSmbCscIoctlCopyChunk attempts to get the file object,
looks into its FsContext2, goes down 0x8 bytes into the structure, obtains
another pointer to some struct, adds 0x10 bytes and expects to find the
value of ‘0x20’ at that memory location. If it gets anything else, it throws
STATUS_INVALID_PARAMETER.

What is this 0x20, located at [[_FILE_OBJECT->FsContext2 + 0x8] + 0x10] and
how it could be set to anything else but 0x20 when attempting to do offline
synchronization?

I do suspect that my filter driver could be involved in this, but I do not
do anything obvious with the FO that would cause this. But then again, I’m
not sure I understand what it is that mrxsmb is checking in this case.

  • Alex
2

Hi Alex,

Good day… as far as MRXSMB filter is concerned it is used to read / write to the physical disk and also responsible for establishing the connectivity between the client and the server for file related activities.

Before i get into the functional aspect, i would like to ask whether you are running latest version of MRXSMB.sys file , because microsoft have modified their driver and updated the latest version which addresses your problem.

3

Hmm… I am running my code against XP SP2, mrxsmb.sys ver. 5.1.2600.2902,
this is probably not the latest. I am going to try this against SP3+, is
there a KB that explains the fix you are referring to?

Thanks,

-Alex

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of xxxxx@live.in
Sent: Friday, October 17, 2008 2:49 AM
To: Windows File Systems Devs Interest List
Subject: RE:[ntfsd] MRXSMB returns STATUS_INVALID_PARAMETER

Hi Alex,

Good day… as far as MRXSMB filter is concerned it is used to read / write
to the physical disk and also responsible for establishing the connectivity
between the client and the server for file related activities.

Before i get into the functional aspect, i would like to ask whether you are
running latest version of MRXSMB.sys file , because microsoft have modified
their driver and updated the latest version which addresses your problem.

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