Bug#474771: pbuilder: No unmount on failed mount

[Carl Fürstenberg]

Package: pbuilder
Version: 0.179
Severity: grave
Justification: causes data loss

If a BINDMOUNTS variable in pbuilderrc contains a non-existing source to
mount, the previous mounted points are not unmounted, and the try to
delete the content of the chroot is thus trying to delete the content in
the mounted points.

As it's a chroot we are talking about, there is no security left to talk
about, though the problem could be that someone accidentally adds an
wrong point to mount, and thus "accidentally" deletes $HOME or similar
:).

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

Kernel: Linux 2.6.22-1-686 (SMP w/1 CPU core)
Locale: LANG=sv_SE.UTF-8, LC_CTYPE=sv_SE.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/bash

Versions of packages pbuilder depends on:
ii  cdebootstrap                  0.5.1      Bootstrap a Debian system
ii  coreutils                     6.10-6     The GNU core utilities
ii  debconf [debconf-2.0]         1.5.20     Debian configuration management sy
ii  debianutils                   2.28.4     Miscellaneous utilities specific t
ii  debootstrap                   1.0.8      Bootstrap a basic Debian system
ii  gcc                           4:4.2.3-7  The GNU C compiler
ii  wget                          1.11.1-1   retrieves files from the web

Versions of packages pbuilder recommends:
ii  cowdancer                     0.44       Copy-on-write directory tree utili
ii  devscripts                    2.10.23    scripts to make the life of a Debi
ii  fakeroot                      1.9.4      Gives a fake root environment
ii  sudo                          1.6.9p15-1 Provide limited super user privile

-- debconf information:
  pbuilder/nomirror:
* pbuilder/mirrorsite: http://ftp.se.debian.org/debian/
  pbuilder/rewrite: false