[Xymon] Bug report: Crash xymond_rrd

[Henrik Størner]

On 31-01-2013 15:51, nloyau.ext at orange.com wrote:
>           I discovered a bug in xymond_rrd module present in release
> 4.3.7 and after.
>           Some times function update_rrd in do_rrd.c msg pointer (*msg)
> can be null. That cause an segfault at strchr call.
>
> Following the coredump analyse
>
> #0 0xb775e424 in __kernel_vsyscall ()
> #1 0xb741e781 in raise () from /lib/i686/cmov/libc.so.6
> #2 0xb7421bb2 in abort () from /lib/i686/cmov/libc.so.6
> #3 0x08070723 in sigsegv_handler (signum=11) at sig.c:57
> #4 <signal handler called>
> #5 0xb7466a83 in strchr () from /lib/i686/cmov/libc.so.6
> #6 0x08050b80 in do_ncv_rrd (hostname=0xb6c847af
> "lvmpitg-sql02o.lvm93.cvf",
>      testname=0xb6c847c8 "mbs_oracle1", classname=0x807fc0d "",
>      pagepaths=0x807fc0d "", msg=0x0, tstamp=1359477166) at rrd/do_ncv.c:54
> #7 0x0805a45f in update_rrd (hostname=0xb6c847af
> "lvmpitg-sql02o.lvm93.cvf",
>      testname=0xb6c847c8 "mbs_oracle1", msg=0x0, tstamp=1359477166,
>      sender=0xb6c847a1 "10.193.26.14", ldef=0x9f5d608,
> classname=0x807fc0d "",
>      pagepaths=0x807fc0d "") at do_rrd.c:712
> #8 0x0804a90f in main (argc=3, argv=0xbfadf744) at xymond_rrd.c:369

I can see how this can happen, and it should not crash on that. But the 
underlying problem is that your host lvmpitg-sql02o.lvm93.cvf sends a 
status- or data-message with no data in it - not even a new-line after 
the first line.

A better patch for this is attached, it handles all cases where there is 
a null message, not just the NCV case.

Regards,
Henrik

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