[Secure-testing-team] Bug#574832: [security] possible symlink attack against /tmp/ddclient.cache

[Teodor]

Package: ddclient
Version: 3.8.0-10
Severity: grave
Tags: security
Justification: user security hole

Hi,

A local user could perform a symlink attack against /tmp/ddclient.cache file.
I see two solutions for this problem:
1) use /var/run/ddclient.cache as the cache file (only root has access here)
2) use `mktemp' to create a non-predictable temporary file.

The first solution seem to be the best as it avoids the complexity of working
with non-predictable temporary files (create, find, update, close).

Thanks

-- System Information:
Debian Release: squeeze/sid
  APT prefers testing
  APT policy: (990, 'testing'), (500, 'unstable')
Architecture: amd64 (x86_64)

Kernel: Linux 2.6.32-4-amd64 (SMP w/2 CPU cores)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash

Versions of packages ddclient depends on:
ii  debconf [debconf-2.0]        1.5.28      Debian configuration management sy
ii  initscripts                  2.87dsf-8.1 scripts for initializing and shutt
ii  lsb-base                     3.2-23      Linux Standard Base 3.2 init scrip
ii  perl [perl5]                 5.10.1-11   Larry Wall's Practical Extraction 

Versions of packages ddclient recommends:
ii  libio-socket-ssl-perl         1.31-1     Perl module implementing object or

ddclient suggests no packages.

-- debconf information excluded