Re: [Dvipng] DVIPNG segfault on DVI output of simple TEX file?

[Shriramana Sharma]

On Mon, Jun 17, 2013 at 12:05 PM, Shriramana Sharma <address@hidden> wrote:
> Given all this, it would seem that since the only change from Precise
> is due to the kpathsea, that should be the problem. I have reported:
> https://bugs.launchpad.net/ubuntu/+source/dvipng/+bug/1191673

OK so I built dvipng with -g3 and then ran gdb on it -- it seems that
dvipng is dereferencing a null pointer and that's the reason for the
segfault. So the problem may actually be within dvipng itself. I mean,
looking at the last few lines:

352             colornamep=LoadColornameFile(colordef[0]);
(gdb)
353           tmp=colornamep;
(gdb) print tmp
$11 = (struct colorname *) 0x0
(gdb) next
354           while((tmp->next!=NULL || colordef[unloaded]!=NULL)
(gdb) print tmp
$13 = (struct colorname *) 0x0
(gdb) next
Program received signal SIGSEGV, Segmentation fault.

It is evident that there is no check here to ensure that tmp is *not*
NULL before dereferencing it by -> on line 354.

-- 
Shriramana Sharma ஶ்ரீரமணஶர்மா श्रीरमणशर्मा

dvipng-segfault-debug-gdb-session.txt
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