[Pkg-samba-maint] Bug#660431: cifs-utils: Only root can unmount user-mounted share

[Vladimir Kudrya]

Package: cifs-utils
Version: 2:5.3-1
Severity: normal

Hello everyone!
I'm running Debian testing.
There is a cifs share that is mounted by users.
fstab line:
//fileserver.domain.local/share /mnt/share cifs user,noauto,noexec 0 0

mount by user is succsessful, but trying to unmount it by the same user with either
"umount /mnt/share" or "umount //main.virton.local/soft" results in error:

"umount: only root can unmount //main.virton.local/soft from /mnt/share"

I tried differend ownership and mode for mountpoint, with the same result.
Both mount.cifs and umount binaries have SUID bit.
There is also no difference if local and remote usernames are the same or not.

I have also checked if same problem happens on local filesystems: 
nope, I can mount and unmount local filesystem from user if it has 'user' option
in fstab. So it seems to be cifs-related, not umount.

-- System Information:
Debian Release: wheezy/sid
  APT prefers testing
  APT policy: (900, 'testing'), (500, 'unstable'), (1, 'experimental')
Architecture: i386 (i686)

Kernel: Linux 3.2.0-1-686-pae (SMP w/4 CPU cores)
Locale: LANG=ru_RU.UTF-8 at ISO, LC_CTYPE=ru_RU.UTF-8 at ISO (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash

Versions of packages cifs-utils depends on:
ii  libc6         2.13-26
ii  libkeyutils1  1.5.2-2
ii  libkrb5-3     1.10+dfsg~beta1-2
ii  libtalloc2    2.0.7+git20120207-1
ii  libwbclient0  2:3.6.3-1
ii  samba-common  2:3.6.3-1

Versions of packages cifs-utils recommends:
pn  keyutils  1.5.2-2
pn  winbind   <none>

Versions of packages cifs-utils suggests:
ii  smbclient  2:3.6.3-1

-- no debconf information