[Xymon] Bug report: Crash xymond_rrd

[nloyau.ext at orange.com]

Hello Xymon team,

         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 have modified source code to control msg content.
See the attachement.

I suppose that isn't the best way to procede but that work better now.


    Best regards,

*Nicolas LOYAU*


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--- do_rrd.c	2011-11-30 11:07:02.000000000 +0100
+++ ../../xymon-4.3.7/xymond/do_rrd.c	2013-01-30 15:32:59.000000000 +0100
@@ -676,6 +676,9 @@
 	int res = 0;
 	char *id;
 
+	if (msg ==NULL)
+			return -1;
+
 	MEMDEFINE(rrdvalues);
 
 	if (ldef) id = ldef->xymonrrdname; else id = testname;