[Secure-testing-team] Bug#543785: backintime-common: backintime make world readable file in backup when it remove old backup

[Rémi Vanicat]

Package: backintime-common
Version: 0.9.26-2
Severity: grave
Tags: security
Justification: user security hole

When asking backintime to remove an old backup, it first change mode
of all file of the backup to 777, allowing potentially every local
user to read and modify those before they are deleted (and this could take some
time). 

Worst still, if a file is shared between several backup, as the file's
mode are also shared, it stay world readable and writable in those
other backup.

Note that one do not need to change the mode of a file to suppress it:
only the mode of the directory need to be changed. The other advantage
to change the mode only for directories is that they are not shared
between backup, so the changed mode don't stay for long period of
time.



-- System Information:
Debian Release: squeeze/sid
  APT prefers transitional
  APT policy: (500, 'transitional'), (500, 'unstable'), (500, 'testing'), (1, 'experimental')
Architecture: amd64 (x86_64)

Kernel: Linux 2.6.30.4 (SMP w/2 CPU cores)
Locale: LANG=fr_FR.UTF-8, LC_CTYPE=fr_FR.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/bash

Versions of packages backintime-common depends on:
ii  cron                          3.0pl1-106 process scheduling daemon
ii  python                        2.5.4-2    An interactive high-level object-o
ii  python-support                1.0.3      automated rebuilding support for P
ii  rsync                         3.0.6-1    fast remote file copy program (lik

backintime-common recommends no packages.

backintime-common suggests no packages.

-- no debconf information