[linux-cifs-client] Re: CIFS and Windows 2003 Server shares

I wanted to add a 'me too' but also provide some more details about what 
I am seeing.  Since my setup involves RHEL samba servers and RHEL cifs 
clients it may provide a good environment for debugging.

My problem looks to be the same as Leonardo with just one slight 

Please let me know if there is any further debugging information I can 
provide.  I would also be interested to know the downside of using this 
patch since it seems to work, albeit non-optimally.

Thanks!

  --Rob

======================  transcript demonstrating failure 
===========================
[root@wink ~]# cat /proc/fs/cifs/MultiuserMount
1
[root@wink ~]# mount -t cifs //curie.cs.indiana.edu/robh /mnt/robh -o 
user=robh
Password:
[root@wink ~]# df /mnt/robh
Filesystem           1K-blocks      Used Available Use% Mounted on
//curie.cs.indiana.edu/robh
                     1692109088 537737952 1068416960  34% /mnt/robh
[root@wink ~]# cat /proc/fs/cifs/DebugData
Display Internal CIFS Data Structures for Debugging
---------------------------------------------------
CIFS Version 1.50cRH
Active VFS Requests: 0
Servers:
1) Name: 129.79.246.140  Domain: WORKGROUP Mounts: 1 OS: Unix 
        NOS: Samba 3.0.28-1.el5_2.1     Capability: 0x80f3fd
        SMB session status: 1   TCP status: 1
        Local Users To Server: 1 SecMode: 0x3 Req On Wire: 0
MIDs:

Shares:
1) \\curie.cs.indiana.edu\robh Uses: 1 Type: NTFS DevInfo: 0x0 
Attributes: 0x2b
PathComponentMax: 255 Status: 1 type: 0
[root@wink ~]# mount -t cifs //curie.cs.indiana.edu/somebogususer 
/mnt/somebogususer -o user=somebogususer
Password:
mount error 13 = Permission denied
Refer to the mount.cifs(8) manual page (e.g.man mount.cifs)

       -> This was just a bogus username and I just hit enter at the 
password prompt so authentication failed

[root@wink ~]# df /mnt/robh
df: `/mnt/robh': Input/output error
[root@wink ~]# ls /mnt/robh
ls: /mnt/robh: Input/output error
[root@wink ~]# cat /proc/fs/cifs/DebugData
Display Internal CIFS Data Structures for Debugging
---------------------------------------------------
CIFS Version 1.50cRH
Active VFS Requests: 0
Servers:
1) Name: 129.79.246.140  Domain: WORKGROUP Mounts: 1 OS: Unix 
        NOS: Samba 3.0.28-1.el5_2.1     Capability: 0x80f3fd
        SMB session status: 2
Shares:
1) \\curie.cs.indiana.edu\robh Uses: 1 Type: NTFS DevInfo: 0x0 
Attributes: 0x2b
PathComponentMax: 255 Status: 1 type: 0

NOTES: 

  1) It doesn't seem to matter what I do with the second mount command.  
In this case, I just used some nonexistant username but the behavior is 
the same if I use a real user, with or without successful authentication.
  2) The diffs in the DebugData output show that the "SMB session 
status" changes from 1 to 2 and the "Local Users To Server" disappears 
as does the (empty) "MIDs:" section.

Jeff Layton wrote:
> On Tue, 6 Jan 2009 18:24:53 -0200
> "Leonardo Chiquitto" <leonardo.lists@gmail.com> wrote:
>
>   
>> On Fri, Dec 19, 2008 at 11:12 AM, Leonardo Chiquitto
>> <leonardo.lists@gmail.com> wrote:
>>     
>>> Hello,
>>>
>>> I'm doing some tests with CIFS client 1.54, trying to discover what
>>> changed with Windows 2003 server that is resulting in a different
>>> behavior from previous Windows versions. In the end, the goal is
>>> to understand whether this is something we can workaround / avoid
>>> on the client side.
>>>
>>> The test:
>>> - the same share is mounted twice with different user names
>>> - the server is not a domain controller or member server
>>> - the server doesn't "know" the users
>>> - "Everyone" and "Guest" have full permissions in the share
>>>
>>> The following commands were used:
>>>
>>> # mount -t cifs //192.168.8.1/Shared /mnt/a -o
>>>  noacl,noperm,user=john,dir_mode=0700,domain=DOMAIN,rw
>>> # mount -t cifs //192.168.8.1/Shared /mnt/b -o
>>>  noacl,noperm,user=jeff,dir_mode=0700,domain=DOMAIN,rw
>>>
>>> Results with Windows 2000 Server:
>>>
>>> - Both mount points are accessible in the client:
>>>
>>> client:/mnt # ls -la
>>> total 8
>>> drwxr-xr-x  4 root root 4096 Dec  9 19:14 .
>>> drwxr-xr-x 31 root root 4096 Dec 15 11:40 ..
>>> drwx------  1 root root    0 Dec 15  2008 a
>>> drwx------  1 root root    0 Dec 15  2008 b
>>>
>>> - "net session" output from server:
>>>
>>> Computer               User name            Client Type       Opens Idle time
>>> -------------------------------------------------------------------------------
>>> \\192.168.8.1          JOHN                 Linux version 2.6     0 00:01:40
>>> \\192.168.8.1          JEFF                 Linux version 2.6     0 00:01:40
>>>
>>> * We can see that Windows 2000 Server keeps the user name provided
>>> by the client.
>>>
>>> Results with Windows 2003 Server:
>>>
>>> - Just the mount point mounted last is accessible:
>>>
>>> client:/mnt # ls -la
>>> ls: cannot access a: Permission denied
>>> total 8
>>> drwxr-xr-x  4 root root 4096 Dec  9 19:14 .
>>> drwxr-xr-x 31 root root 4096 Dec 15 11:40 ..
>>> d?????????  ? ?    ?       ?            ? a
>>> drwx------  1 root root    0 Dec 15  2008 b
>>>
>>> - "net session" output from the server:
>>>
>>> Computer               User name            Client Type       Opens Idle time
>>> -------------------------------------------------------------------------------
>>> 192.168.8.1          GUEST                Linux version 2.6     0 000012
>>>
>>> * We can see that just one session remains and the user name was mapped to
>>> GUEST.
>>>
>>> I suppose this is expected, but I really would like to understand what is
>>> the underlying cause.
>>>       
>> I couldn't find a solution for this problem yet, but I have more information
>> to share:
>>
>> - The problem also happens with Windows 2008 Server and earlier versions
>>   of the CIFS client (tested with 1.20).
>>
>> Playing with the code, I found that disabling TCP connection sharing by
>> applying the following patch, will workaround the problem: I can now
>> mount the same share twice with different users and still have access to
>> both.
>>
>> --- linux.orig/fs/cifs/connect.c
>> +++ linux/fs/cifs/connect.c
>> @@ -1463,9 +1463,11 @@ cifs_get_tcp_session(struct smb_vol *vol
>>  	}
>>
>>  	/* see if we already have a matching tcp_ses */
>> +#if 0
>>  	tcp_ses = cifs_find_tcp_session(&addr);
>>  	if (tcp_ses)
>>  		return tcp_ses;
>> +#endif
>>
>>  	tcp_ses = kzalloc(sizeof(struct TCP_Server_Info), GFP_KERNEL);
>>  	if (!tcp_ses) {
>>
>> I understand that this is not a valid fix, it was made only for debugging.
>>
>> It's also interesting that even when not sharing the TCP connection,
>> "net session" output from Windows 2003 still shows only one session
>> opened. Don't laugh, but is there any documentation that describes what
>> defines an unique SMB session for different versions of Windows?
>>
>>     
>
> Not that I know of...
>
> The Linux CIFS code has 3 layered "pieces" when setting up a mount:
>
> TCP Session (basically the socket)
> SMB Session (generally separated by username)
> Tree Connection (sort of the actual "mount")
>
> These are all "many to one". i.e. a TCP session can have several SMB
> sessions, and a SMB session can have several tcons.
>
> It sounds almost like the server is squishing the SMB sessions together
> and getting them confused for some reason. You might want to look at
> what's going on on the wire with the SMB sessions.
>
> I also wonder whether the server may be presenting share-level security
> mounts, but that would be very odd for a server as new as win2k3.
>
>

[linux-cifs-client] Re: CIFS and Windows 2003 Server shares

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