[DVDnav-discuss] [patch] Fix SIGSEGV in dvdnav_describe_title_chapters

Sylvain HENRY hsyl20 at gmail.com
Wed Apr 4 14:56:25 CEST 2012

My patch checks that cellnr is strictly inferior to endcellnr. It was 
only based on the fact that this condition was true for every case 
except the bogus case (cellnr=0 and endcellnr=0).

If my assumption is wrong, a patch that excludes the case "cellnr=0" 
would do the trick.


Le 03/04/2012 20:08, Erik Hovland a écrit :
> On Mon, Apr 2, 2012 at 12:16 PM, Sylvain HENRY<hsyl20 at gmail.com>  wrote:
>> Hi,
>> Please consider checking and applying the attached patch. It fixes a
>> segfault occuring with some DVDs. It seems to be the same problem as the one
>> mentionned here:
>> https://bugs.launchpad.net/ubuntu/+source/libdvdnav/+bug/934471
>> In my case, "cellnr" and "endcellnr" variables were set to 0 when the crash
>> occured.
> Although I don't doubt that your patch fixes the problem for you it seems
> to address a different problem. The crash is likely because:
> cell =&pgc->cell_playback[cellnr-1];
> In this case cellnr should never be zero because cellnr-1 will evaluate to
> UINT_MAX. A patch that is more likely to be accepted is one that
> checks cellnr. What does the attached patch do?
> E

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