Bug report: Crash xymond_rrd

On 31-01-2013 15:51, user-9b349bc9d31a@xymon.invalid 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