[cifs-protocol] [REG: 111101256623456] SMB2: ioctl max size

[Edgar Olougouna]

Metze,

Upon investigation, it appears that there are some size limits applied on SMB2 IOCTL commands in Windows Server 2008 and Windows Server 2008 R2. 
The behavior is version-specific. A future release of MS-SMB2 will be updated to reflect the following logic. The change will affect Section “3.3.5.15   Receiving an SMB2 IOCTL Request”.
The server SHOULD fail the request with STATUS_INVALID_PARAMETER if InputCount or MaxInputResponse or MaxOutputResponse do not meet the following conditions:
Windows 7 and Windows Server 2008 R2 SMB2 servers fail an IOCTL with STATUS_INVALID_PARAMETER if InputCount or MaxInputResponse or MaxOutputResponse is greater than an implementation-specific value. When the connection is on direct TCP transport, Windows 7 and Windows Server 2008 R2 SMB2 Servers set this value to 1024*1024 and on NetBIOS over TCP transport, the value is 64*1024.
Windows Vista and Windows Server 2008 SMB2 servers fail an IOCTL request with STATUS_INVALID_PARAMETER if [ max(InputCount, MaxInputResponse) + max(OutputCount, MaxOutputResponse) ] is greater than 256*1024.

Regards,
Edgar

-----Original Message-----
From: Edgar Olougouna 
Sent: Friday, October 14, 2011 1:36 PM
To: Stefan (metze) Metzmacher (metze at samba.org); pfif at tridgell.net; cifs-protocol at cifs.org
Subject: RE: [REG: 111101256623456] SMB2: ioctl max size

Metze,

I have investigated this and engaged the product team to clarify SMB2 IOCTL sizes limit. I will update you as soon as I have news.

Regards,
Edgar

-----Original Message-----
From: Edgar Olougouna 
Sent: Wednesday, October 12, 2011 10:47 AM
To: Stefan (metze) Metzmacher (metze at samba.org); pfif at tridgell.net; cifs-protocol at cifs.org
Subject: [REG: 111101256623456] SMB2: ioctl max size

[Dochelp to bcc]
[Adding case number in subject]

Metze,

I have opened the case number 111101256623456 for this inquiry. One of my colleagues will take ownership and follow up soon.

Regards,
Edgar

-----Original Message-----
From: Stefan (metze) Metzmacher [mailto:metze at samba.org] 
Sent: Wednesday, October 12, 2011 10:35 AM
To: Interoperability Documentation Help; pfif at tridgell.net; cifs-protocol at cifs.org
Subject: SMB2: ioctl max size

Hi dochelp,

I wondering if there are any size limitations based on MaxTransactSize, MaxReadSize and/or MaxWriteSize in SMB2 IOCTL?

I can't find anything related in the docs, but I guess there is a size limitation too.

metze