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Re: possible samba security problem



On Sat, 29 Jan 2005 14:50:03 +0100, Ruben van der Leij wrote:

>+++ Nick Boyce [29/01/05 02:56 +0000]:
>
>> I think it
>> should be okay to simply change the permissions on
>> /var/run/samba/locking.tdb so only root can access it.  There's no
>> real need for ordinary users to use smbstatus anyway.  IMHO.
>
>Have you actually *tried* that 'solution'? 

I confess at the time I wrote that I *hadn't* tried it - but I have
now - I just did an experiment on a Woody box running a backport of
Samba 2.2.8a :

==================< cut >==================
W1LWS001:~$ smbstatus

Samba version 2.2.8a-1.woody for Debian
Service      uid      gid      pid     machine
----------------------------------------------

No locked files

W1LWS001:~$ smbclient -L \\localhost -N
added interface ip=xxx.yyy.47.40 bcast=xxx.yyy.47.255
nmask=255.255.255.0
Anonymous login successful
Domain=[MYDOMAIN] OS=[Unix] Server=[Samba 2.2.8a-1.woody for Debian]

        Sharename      Type      Comment
        ---------      ----      -------
        IPC$           IPC       IPC Service (Samba 2.2.8a)
        ADMIN$         Disk      IPC Service (Samba 2.2.8a)

        Server               Comment
        ---------            -------
        W1LWS001             Samba 2.2.8a

        Workgroup            Master
        ---------            -------
        MYDOMAIN

W1LWS001:~$ su -
Password:
W1LWS001:~# ls -l /var/run/samba
total 40
-rw-r--r--    1 root     root          696 Jan 31 00:39 brlock.tdb
-rw-r--r--    1 root     root         8192 Jan 30 19:30
connections.tdb
-rw-r--r--    1 root     root          696 Jan 31 00:39 locking.tdb
-rw-------    1 root     root          696 Jan 30 19:30 messages.tdb
-rw-r--r--    1 root     root         3599 Nov 17 06:25 namelist.debug
-rw-r--r--    1 root     root           20 Jan 30 19:30 nmbd.pid
-rw-r--r--    1 root     root           20 Jan 30 19:30 smbd.pid
-rw-r--r--    1 root     root         8192 Jan 30 19:30 unexpected.tdb
W1LWS001:~# chmod 640 /var/run/samba/locking.tdb
W1LWS001:~# ls -l /var/run/samba/locking.tdb
-rw-r-----    1 root     root          696 Jan 31 00:39
/var/run/samba/locking.tdb
W1LWS001:~# logout

W1LWS001:~$ smbclient -L \\localhost -N
added interface ip=xxx.yyy.47.40 bcast=xxx.yyy.47.255
nmask=255.255.255.0
Anonymous login successful
Domain=[MYDOMAIN] OS=[Unix] Server=[Samba 2.2.8a-1.woody for Debian]

        Sharename      Type      Comment
        ---------      ----      -------
        IPC$           IPC       IPC Service (Samba 2.2.8a)
        ADMIN$         Disk      IPC Service (Samba 2.2.8a)

        Server               Comment
        ---------            -------
        W1LWS001             Samba 2.2.8a

        Workgroup            Master
        ---------            -------
        MYDOMAIN

W1LWS001:~$ smbstatus

Samba version 2.2.8a-1.woody for Debian
Service      uid      gid      pid     machine
----------------------------------------------

ERROR: Failed to initialise locking database
Can't initialise locking module - exiting
==================< cut >==================

Doesn't seem to cause a problem. Might be different with Samba 3.x.x
though, but I don't have any of those at present.


>Perhaps smbstatus isn't doing anything that it shouldn't. 
>It might even be accurately emulating behaviour available 
>on windows.

Just because Windows does it doesn't necessarily mean it's a good
thing ;-)

Cheers,
Nick Boyce
Bristol, UK
--
"If you assume that there's no hope, you guarantee there will be no hope.
If you assume that there is an instinct for freedom, there are
opportunities to change things."  - Noam Chomsky



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