| Message ID | 20210905192418.25970-3-michael@niedermayer.cc |
|---|---|
| State | New |
| Headers | show |
| Series | [FFmpeg-devel,1/4] avformat/mxfdec: check channel number in mxf_get_d10_aes3_packet() | expand |
| Context | Check | Description |
|---|---|---|
| andriy/make_x86 | success | Make finished |
| andriy/make_fate_x86 | success | Make fate finished |
| andriy/make_ppc | success | Make finished |
| andriy/make_fate_ppc | success | Make fate finished |
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 <michael@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. - Andreas
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 <michael@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 [...]
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;
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 <michael@niedermayer.cc> --- libavcodec/h264_parser.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)