tree e54a71369d7fe9e9e4685691f71c422122ce3989
parent 973ca497953bfc668f9879c3977942a1c6e1e536
author Michael Scherer <misc@zarb.org> 1358012119 +0100
committer Willy Tarreau <w@1wt.eu> 1358501125 +0100

BUG/MEDIUM: remove supplementary groups when changing gid

Without it, haproxy will retain the group membership of root, which may
give more access than intended to the process. For example, haproxy would
still be in the wheel group on Fedora 18, as seen with :

  # haproxy -f /etc/haproxy/haproxy.cfg

  # ps a -o pid,user,group,command | grep hapr
  3545 haproxy  haproxy  haproxy -f /etc/haproxy/haproxy.cfg
  4356 root     root     grep --color=auto hapr
  # grep Group /proc/3545/status
  Groups: 0 1 2 3 4 6 10
  # getent group wheel
  wheel:x:10:root,misc

[WT: The issue has been investigated by independent security research team
     and realized by itself not being able to allow security exploitation.
     Additionally, dropping groups is not allowed to unprivileged users,
     though this mode of deployment is quite common. Thus a warning is
     emitted in this case to inform the user. The fix could be backported
     into all supported versions as the issue has always been there. ]