[Bug 598275] [NEW] munin-node fw_conntrack plugin reports incorrect critical threshold

[Micah Stetson]

Public bug reported:

Binary package hint: munin

Ubuntu 10.04 LTS, munin-node 1.4.4-1ubuntu1.  On my newly installed
Lucid server, Munin's fw_conntrack plugin reports the "critical" number
of network connects as 5 or 6.  This means that I get constant alerts
about having too many network connections.  I think this is actually
caused by a bug in dash's built-in read command.  Fw_conntrack gets its
max connection number by reading /proc/sys/net/ipv4/ip_conntrack_max or
/proc/sys/net/ipv4/netfilter/ip_conntrack_max around line 110 of
/usr/share/munin/plugins/fw_conntrack.  Like this:

    read MAX < /proc/sys/net/ipv4/netfilter/ip_conntrack_max

If I run this in bash:

    bash# read MAX < /proc/sys/net/ipv4/netfilter/ip_conntrack_max && echo good: $MAX || echo bad: $MAX
    good: 7852

but in dash:

    dash# read MAX < /proc/sys/net/ipv4/netfilter/ip_conntrack_max && echo good: $MAX || echo bad: $MAX
    bad: 7

So dash's read is failing AND setting $MAX.  I imagine this is a bug in
dash, but fw_conntrack is also ignoring the fact that read returning
failure.

Changing fw_conntrack's #! line to #!/bin/bash works around the problem,
but I wouldn't call that a fix.

** Affects: munin (Ubuntu)
     Importance: Undecided
         Status: New

-- 
munin-node fw_conntrack plugin reports incorrect critical threshold
https://bugs.launchpad.net/bugs/598275
You received this bug notification because you are a member of Ubuntu
Server Team, which is subscribed to munin in ubuntu.