Hello Stefan, Thank you for your question regarding SMB2. I will have one of my colleagues get back to you so that we can start working on this.
Thanks John Dunning Senior Escalation Engineer Microsoft Corporation US-CSS DSC PROTOCOL TEAM Email: john...@microsoft.com Tele: (469)775-7008 -----Original Message----- From: Stefan (metze) Metzmacher [mailto:me...@samba.org] Sent: Monday, July 06, 2009 3:45 AM To: Interoperability Documentation Help Cc: p...@tridgell.net; cifs-proto...@samba.org Subject: CAR - SMB2 Write and Read in Windows 7 Hi, I'm working on SMB2 support for Samba and noticed a strange behavior regarding the maximum read and write sizes in SMB2. Section "3.3.5.13 Receiving an SMB2 WRITE Request" says the server must return STATUS_INVALID_PARAMETER if the length isn't in the configured range (which is reported to the client in the NEGOTIATE response). The same applies to SMB2 Read requests. However a Windows 7 server doesn't behave like this. (I tested this with Windows 7 RC Build 7100). I've attached 3 network captures to this mail, which demonstrate the wrong behavior. SMB2-CONNECT-w7rc-smb2.002.writesize-01.pcap: - We run our SMB2-CONNECT torture test like this: bin/smbtorture -Utest%test -p 445 //172.31.9.212/torture \ SMB2-CONNECT --option=torture:smb2maxwrite=65537 (I manually excluded the SMB 2.100 dialect in our code) - In Frame 5 SMB 2.002 is negotiated and the server returns MaxReadSize and MaxWriteSize as 65536 (0x00010000). - The Frames 17-71 (wireshark reassembles them in Frame 71) there's a SMB2 Write request with length 65537 (0x00010001). - And the SMB2 Write response in Frame 72 returns STATUS_BUFFER_OVERFLOW instead of STATUS_INVALID_PARAMETER. (Then our test closes the tcp connection) - Now we run our SMB2-CONNECT torture test like this: bin/smbtorture -Utest%test -p 445 //172.31.9.212/torture \ SMB2-CONNECT --option=torture:smb2maxwrite=65536 - The SMB2 Write response in Frame 147 returns STATUS_OK, which is correct. - Also the SMB2 Read response (reassembled) in Frame 285, gets STATUS_OK. SMB2-CONNECT-w7rc-smb2.002.writesize-strange-02.pcap: - Here I manually modified the write/read sizes in the SMB2-CONNECT torture test and ignored any errors. So that we write 65537 bytes and read 65536 bytes. (I also manually excluded the SMB 2.100 dialect in our code) - The SMB2 Write request (reassembled in Frame 142) writes 65537 bytes and gets STATUS_BUFFER_OVERFLOW. - The SMB2 GetInfo response in Frame 146 returns the allocation size and end of file both as 65536, which indicates that the SMB2 Write was just truncated to 65536. - The SMB2 Read request in Frame 155 asks for the first 65536 bytes of the file. - The SMB2 Read response (reassembled) in Frame 223 proves that the truncated Write as it returns the exactly same bytes, which were written before. SMB2-CONNECT-w7rc-smb2.100.writesize-01.pcap: - The behavior in SMB 2.100 mode is even more strange... - We run our SMB2-CONNECT torture test like this: bin/smbtorture -Utest%test -p 445 //172.31.9.212/torture \ SMB2-CONNECT --option=torture:smb2maxwrite=1048576 - In Frame 9 SMB 2.100 is negotiated and the server returns MaxReadSize and MaxWriteSize as 1048576 (0x00100000). - We try a SMB2 Write with length 1048576 (reassembled) in Frame 784, but get STATUS_INVALID_PARAMETER in Frame 787. (Our test closes the connection at this point. - We run our SMB2-CONNECT torture test like this: bin/smbtorture -Utest%test -p 445 //172.31.9.212/torture \ SMB2-CONNECT --option=torture:smb2maxwrite=1048576 - In Frame 795 SMB 2.100 is negotiated and the server returns MaxReadSize and MaxWriteSize as 1048576 (0x00100000). - We try a SMB2 Write with length 65537 (reassembled) in Frame 859, but get STATUS_INVALID_PARAMETER in Frame 861. (Our test closes the connection at this point. - We run our SMB2-CONNECT torture test like this: bin/smbtorture -Utest%test -p 445 //172.31.9.212/torture \ SMB2-CONNECT --option=torture:smb2maxwrite=65536 - In Frame 869 SMB 2.100 is negotiated and the server returns MaxReadSize and MaxWriteSize as 1048576 (0x00100000). - We try a SMB2 Write with length 65536 (reassembled) in Frame 933. - The SMB2 Write response in Frame 935 returns STATUS_OK, which is correct. - Also the SMB2 Read response (reassembled) in Frame 1073, gets STATUS_OK. The major problem is that a client in SMB 2.100 mode can't rely on the values returned in the NEGOTIATE response. I think it would be very, very good if this could be fixed in the final version of Windows 7! metze (Samba Team and PFIF member)
_______________________________________________ cifs-protocol mailing list cifs-protocol@cifs.org https://lists.samba.org/mailman/listinfo/cifs-protocol