[Bug 1022545] Re: Backport upstream bugfix "$PreserveFQDN on" not working properly

[Steve Langasek]

> Minimal risk as the value defined by the patch is only used
> if the $PreserveFQDN variable is defined in /etc/rsyslog.conf,
> which is absent by default.

It turns out this is not the case.  There is a critical regression in
rsyslog as a result of this patch; the value may not be *used* without
$PreserveFQDN, but the code to *set* it is still executed, and there's
an off-by-one error in the patch causing malloc corruption (bug
#1187876).

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Title:
  Backport upstream bugfix "$PreserveFQDN on" not working properly

Status in “rsyslog” package in Ubuntu:
  Fix Released
Status in “rsyslog” source package in Precise:
  Fix Released
Status in “rsyslog” source package in Quantal:
  Won't Fix
Status in “rsyslog” source package in Raring:
  Fix Released

Bug description:
  SRU justification :

  The $PreserveFQDN functionality does not work as expected. Even when
  defining it as 'on', the fully qualified domain name is not reported
  by rsyslog

  Impact :

  Unable to have the FQDN added to the hostname in syslog

  Fix :

  Upstream fix committed to upcoming 7.4 version of rsyslog :

  http://git.adiscon.com/?p=rsyslog.git;a=commitdiff_plain;h=89ace1e401dc179a20ec283c2f7c2f80becf4700

  Test Case :

  1. Configure rsyslog on a system that has the hostname defined with fully
     qualified domain name in /etc/hosts :

  192.168.122.10      rsyslogserver.localdomain.com    rsyslogserver

  The hostname -f command should return the hostname with FQDN appended
  :

  $ hostname -f
  rsyslogserver.localdomain.com

  2. Add the following entry in /etc/rsyslog.conf

  $PreserveFQDN on

  3. Restart rsyslogd :

  $ restart rsyslog

  4. Verify in /var/log/syslog that hostname + fqdn appears :

  Apr 25 14:13:29 rsyslogserver.localdomain.com kernel: imklog 5.8.6,
  log source = /proc/kmsg started.

  With the current version of rsyslog, only the hostname appears

  Regression :

  Minimal risk as the value defined by the patch is only used if the
  $PreserveFQDN variable is defined in /etc/rsyslog.conf, which is
  absent by default.

  Description of the problem :

  When adding $PreserveFQDN on in /etc/rsyslog.conf to have the Fully
  Qualified Domain Name appended to the hostname reported by rsyslog,
  the functionality does not work and only the hostname is reported.

  
  Original description (which is wrong as the cited commit does not fix the problem)

  You will find patch and information here:

  http://git.adiscon.com/?p=rsyslog.git;a=commitdiff;h=dec9bcfe2a869b0f70b5f2a18e08a0322ebf5517

  Please backport this patch for precise.

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