[cifs-protocol] [REG:111052652308584] [ttalpey at microsoft.com: Reminder -- share secdesc and smb2 echo?]

Obaid Farooqi obaidf at microsoft.com
Mon Jun 13 09:42:05 MDT 2011

Hi Volker:
Thanks for your reply. 
I'll look into the questions raised by you and will be in touch as soon as I have an answer.
I did not find a trace attached to this email. Please send me the trace you mentioned.

The changes I sent you will be incorporated in a future release of MS-CIFS/MS-SMB2

Obaid Farooqi
Escalation Engineer | Microsoft

Exceeding your expectations is my highest priority.  If you would like to provide feedback on your case you may contact my manager at allisong at microsoft.com

-----Original Message-----
From: Volker Lendecke [mailto:Volker.Lendecke at SerNet.DE]
Sent: Sunday, June 12, 2011 4:17 AM
To: Obaid Farooqi
Cc: cifs-protocol at samba.org; pfif at tridgell.net; MSSolve Case Email
Subject: Re: [REG:111052652308584] [ttalpey at microsoft.com: Reminder -- share secdesc and smb2 echo?]

On Fri, Jun 10, 2011 at 03:57:19PM +0000, Obaid Farooqi wrote:
> Your observation is correct, and it is the case that the CIFS, SMB or
> SMB2 server MUST first verify that the Share.FileSecurity allows the 
> client-supplied DesiredAccess. If any of the nonzero bits of 
> DesiredAccess are not permitted for the user by the 
> Share.FileSecurity, the server MUST fail the request with 

Thanks. This is for the ntcreate call, right?

> Please let me know if it answers your question. If it does, I'll 
> consider this issue resolved.

It does not fully answer it, sorry. Attached find a network trace against the server where user "vlendec" (the one I'm connecting as) does not have the "full access" right as in the last traces. However, in frames 38/39 it seems that I was able to create a new file, giving it a custom security descriptor. I would have thought that when setting secdescs is forbidden then creating a new file would not allow me to set custom file descriptors using the nttrans create call.
This way it is possible for a user to circumvent the non-ability to set secdescs by just making a copy into a new file.

BTW, the trace is from re-syncing an offline folder after the server came back.

Can you explain that or show where this exception is documented? And, will this end up in the documentation somewhere?



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