[Xymon] Segfault in confreport-critical.sh / confreport.cgi in 4.3.24 (now with backtrace)

[Axel Beckert]

Hi,

On Thu, Dec 10, 2015 at 01:45:49PM +0100, Axel Beckert wrote:
> I don't have a proper backtrace (yet), but I had look at the source
> code and I'm quite confident that the issue is inside the function
> print_alert_recipients() starting at lib/loadalerts.c, line 1124.

Here's the according backtrace. Doesn't look too helpful to me,
though:

# gdb /usr/lib/xymon/server/bin/confreport.cgi ./207855-33-33-11-1449754874-silberspitz--usr-lib-xymon-server-bin-confreport.cgi.core
GNU gdb (Debian 7.7.1+dfsg-5) 7.7.1
[...]
Reading symbols from /usr/lib/xymon/server/bin/confreport.cgi...Reading symbols from /usr/lib/debug/.build-id/f2/5c37643ea6a391c09535cc250d18cef4aa39cf.debug...done.
done.
[New LWP 207855]
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
Core was generated by `/usr/lib/xymon/server/bin/confreport.cgi --env=/usr/lib/xymon/server/etc/xymons'.
Program terminated with signal SIGSEGV, Segmentation fault.
#0  strlen () at ../sysdeps/x86_64/strlen.S:106
106     ../sysdeps/x86_64/strlen.S: No such file or directory.
(gdb) bt
#0  strlen () at ../sysdeps/x86_64/strlen.S:106
#1  0x0000000000403640 in print_host (testcount=18, testnames=0x167dcc0, host=0x166b070) at confreport.c:310
#2  main (argc=<optimized out>, argv=<optimized out>) at confreport.c:876

Line 310 of web/confreport.c looks liek this:

  newitem->visualdata = (char *)realloc(newitem->visualdata, strlen(newitem->visualdata) + strlen(visdata) + 5);

So do I read the backtrace correctly that there was no proper value
(e.g. a null pointer) was passed to strlen()?

Then again I also don't find any file named strlen.S on the system
where I build the packages either. (But it seems to be part of glibc's
source code.)

		Kind regards, Axel Beckert
-- 
Axel Beckert <beckert at phys.ethz.ch>       support: +41 44 633 26 68
IT Services Group, HPT H 6                  voice: +41 44 633 41 89
Departement of Physics, ETH Zurich
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