[syslog-ng] [Bug 39] New: Memory exhaustion when using UDP destination to send to a remote server.

[bugzilla at bugzilla.balabit.com]

https://bugzilla.balabit.com/show_bug.cgi?id=39

           Summary: Memory exhaustion when using UDP destination to send to
                    a remote server.
           Product: syslog-ng
           Version: 2.1.x
          Platform: PC
        OS/Version: Linux
            Status: NEW
          Severity: normal
          Priority: unspecified
         Component: syslog-ng
        AssignedTo: bazsi at balabit.hu
        ReportedBy: gillespiem at pa.net
Type of the Report: ---
   Estimated Hours: 0.0


I have noticed that if syslog-ng receives an ICMP Type 3 / Code 3 message from a syslog-ng server configured as a remote destination
(using UDP as the transport), the syslog-ng process starts consuming more and more memory, finally exhausting all resources. I've found this issue can be 
consistently replicated.

Centos 5.2 (Final)
syslog-ng 2.1.3

syslog-ng.conf (snippet from sending server)
 destination d_syslog_rtr0 {udp("syslog-server.blah.com" port(514));};

Config on receiving server doesn't matter, you can send the packets to a blackhole when replicating the issue.

Steps to replicate:

Using tcpdump, determine the port the sending server is using to send messages. Then, using sing (or any packetcrafting tool), do the following (or similar):

sing -du -S <receiving syslog server IP> -x port-unreach -prot udp -psrc <Sending server source port (determined above)> --pdst 514 <Sending syslog server>

When viewing processes using "top", it's apparent that memory usage of the syslog-ng process starts increasing every ~2 seconds,
until the server has exhausted all memory. (I can replicate this on 3 separate servers)


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