[Ffmpeg-devel] Maybe (?), robustness patch
Michael Niedermayer
michaelni
Mon Jan 23 15:20:30 CET 2006
Hi
On Mon, Jan 23, 2006 at 08:05:47AM +0000, Mean wrote:
> Michael Niedermayer wrote:
> >Hi
> >
> >On Sun, Jan 22, 2006 at 05:31:16PM +0000, Mean wrote:
> >
> >>Hi,
> >> While trying to create a correct avcC atom with lavformat/x264, i've
> >>made some (interestingly ?) broken mp4 files.
> >> One of them makes lavcodec crash hard, which is bad and uncommon.
> >>
> >> The problem is that in that case bit_length ends up being equal to
> >>-1, hence the crash a bit later
> >> I'm not sure it is a fix of great interest since such broken files
> >>should not exist at all, but anyway.
> >>
> >> The trivial check that avoids the hard crash is below
> >>
> >> One such funny file is available here
> >>
> >>http://fixounet.free.fr/avidemux/win32/broken_h264_makes_lavcodec_crash.mp4
> >> No image, but no crash either.
> >>
> >>Thanks.
> >>
> >>
> >>
> >> Index: h264.c
> >>===================================================================
> >>--- h264.c (revision 1724)
> >>+++ h264.c (working copy)
> >>@@ -7458,7 +7458,13 @@
> >> ptr= decode_nal(h, buf + buf_index, &dst_length, &consumed,
> >>h->is_avc ? nalsize : buf_size - buf_index);
> >> if(ptr[dst_length - 1] == 0) dst_length--;
> >> bit_length= 8*dst_length - decode_rbsp_trailing(ptr +
> >>dst_length - 1);
> >>-
> >>+ /* MEANX */
> >>+ if(bit_length<=0)
> >>+ {
> >>+ av_log(h->s.avctx, AV_LOG_ERROR, "h264: bit length
> >>computing error, broken stream ? \n");
> >>+ return -1;
> >>+ }
> >>+ /* /MEANX */
> >>
> >
> >can you submit patches without addng your name to every chunk? just imagine
> >how ffmpegs source would look like if everyone did this ...
> >
> >bit_length<0 also needs dst_length=0 and that already seems wrong ...
> >
> >[...]
> >
> Hello,
> Sorry to be thick, but does that mean that a check for dst_length
> is also need or does that mean
> that it is of no interest ?
IMHO a check for dst_length would be ideal yes
[...]
--
Michael
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