On Sun, Sep 05, 2021 at 09:51:32PM +0200, Andreas Rheinhardt wrote: > Michael Niedermayer: > > Fixes: Assertion failure > > Fixes: > > 37463/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_H264_fuzzer-4914693494931456 > > > > Found-by: continuous fuzzing process > > https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg > > Signed-off-by: Michael Niedermayer <mich...@niedermayer.cc> > > --- > > libavcodec/h264_parser.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/libavcodec/h264_parser.c b/libavcodec/h264_parser.c > > index 01ea016409..47cc1d5c78 100644 > > --- a/libavcodec/h264_parser.c > > +++ b/libavcodec/h264_parser.c > > @@ -87,7 +87,7 @@ static int h264_find_frame_end(H264ParseContext *p, const > > uint8_t *buf, > > i = next_avc; > > for (j = 0; j < p->nal_length_size; j++) > > nalsize = (nalsize << 8) | buf[i++]; > > - if (!nalsize || nalsize > buf_size - i) { > > + if (!nalsize || i > buf_size || nalsize > buf_size - i) { > > av_log(logctx, AV_LOG_ERROR, "AVC-parser: nal size > > %"PRIu32" " > > "remaining %d\n", nalsize, buf_size - i); > > return buf_size; > > > The cheapest fix for this is to make nalsize int64_t. But actually this > whole code looks highly weird: In contrast to how the parsing API is > supposed to be, it requires the whole buffer being available, despite > the PARSER_FLAG_COMPLETE_FRAMES being unset.
you are correct, this implementation assumes things beyond what the API alone gurantees packetization wise. the various specs gurantee that though i think for H.264 If you or someone wants to implement the generic case, i think its a good idea. OTOH if not i dont think that will be a problem either. as you prefer int64_t instead of the check, i will apply that change instead thx [...] -- Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB Rewriting code that is poorly written but fully understood is good. Rewriting code that one doesnt understand is a sign that one is less smart than the original author, trying to rewrite it will not make it better.
signature.asc
Description: PGP signature
_______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
