[cifs-protocol] SR# 117072516091337 :SMB2 ECHO request

[Jeff McCashland]

[-casemail]

Hi Andreas,

Here is what we came up with for the next release of the document:

In section 3.3.5.17 Receiving an SMB2 ECHO Request the following has been added:
The server MUST verify the session, as specified in section 3.3.5.2.9, if any of the following conditions is TRUE:
§ SMB2_FLAGS_SIGNED bit is set in the Flags field of the SMB2 header of the request.
§ The request is not encrypted, and the SessionId field of the SMB2 header of the request is not zero.

Best regards,
Jeff McCashland | Senior Escalation Engineer | Microsoft Protocol Open Specifications Team 
Phone: +1 (425) 703-8300 x38300 | Hours: 9am-5pm | Time zone: (UTC-08:00) Pacific Time (US and Canada)
Local country phone number found here: http://support.microsoft.com/globalenglish | Extension 1138300
We value your feedback.  My manager is Rama Ganesan (ramagane), +1 (425) 703-8712

-----Original Message-----
From: Jeff McCashland 
Sent: Monday, September 18, 2017 4:19 PM
To: 'Andreas Schneider' <asn at samba.org>
Cc: cifs-protocol <cifs-protocol at lists.samba.org>; MSSolve Case Email <casemail at microsoft.com>
Subject: RE: SR# 117072516091337 :SMB2 ECHO request

Hi Andreas,

My suggestion below was rejected as inappropriate for section 2, since it isn't a MUST rule. In fact, it is felt that the documentation covers the issue as the server processing rules for every SMB2 command (except NEGOTIATE and SESSION_SETUP) specify verifying the SessionId with the single exception of ECHO. We don't document what isn't done, just what we do. By implication, SessionID can be 0 for ECHO (unless the message is signed).

Hope that helps!

Best regards,
Jeff McCashland | Senior Escalation Engineer | Microsoft Protocol Open Specifications Team
Phone: +1 (425) 703-8300 x38300 | Hours: 9am-5pm | Time zone: (UTC-08:00) Pacific Time (US and Canada) Local country phone number found here: http://support.microsoft.com/globalenglish | Extension 1138300 We value your feedback.  My manager is Rama Ganesan (ramagane), +1 (425) 703-8712

-----Original Message-----
From: Andreas Schneider [mailto:asn at samba.org]
Sent: Monday, July 31, 2017 1:19 AM
To: Jeff McCashland <jeffm at microsoft.com>
Cc: cifs-protocol <cifs-protocol at lists.samba.org>; MSSolve Case Email <casemail at microsoft.com>
Subject: Re: SR# 117072516091337 :SMB2 ECHO request

On Thursday, 27 July 2017 21:25:51 CEST Jeff McCashland wrote:
> Hi Andreas,

Hi Jeff,

> Normally, this type of information would go into the processing rules 
> for the Client (Section 3.2). However, the gist of what I explained 
> below is that SMB2 doesn't have any rules for the client to process 
> the ECHO command. The client is free to use and process ECHO as 
> needed, as long as the structure in section 2.2 is met.
> 
> We could add something like:
> 
> 2.2.1.1	SMB2 Packet Header - ASYNC
> SessionId (8 bytes): Uniquely identifies the established session for 
> the command. This field MUST be set to 0 for an SMB2 NEGOTIATE Request 
> (section
> 2.2.3) and for an SMB2 NEGOTIATE Response (section 2.2.4). SessionId 
> MAY be set to 0 for an SMB2 ECHO Request (section 2.2.28) and for an
> SMB2 ECHO Response (section 2.2.29).
> 
> 2.2.1.2	SMB2 Packet Header - SYNC
> SessionId (8 bytes): Uniquely identifies the established session for 
> the command. This field MUST be set to 0 for an SMB2 NEGOTIATE Request 
> (section
> 2.2.3) and for an SMB2 NEGOTIATE Response (section 2.2.4). SessionId 
> MAY be set to 0 for an SMB2 ECHO Request (section 2.2.28) and for an
> SMB2 ECHO Response (section 2.2.29).
> 
> Would that be helpful?


I think that's perfect.


Thanks,


	Andreas


-- 
Andreas Schneider                   GPG-ID: CC014E3D
Samba Team                             asn at samba.org
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