On 10/4/2020 5:57 PM, Michael Niedermayer wrote: > On Sun, Oct 04, 2020 at 05:04:05PM -0300, James Almer wrote: >> On 10/4/2020 4:41 PM, Michael Niedermayer wrote: >>> Fixes: OOM >>> Fixes: >>> 23817/clusterfuzz-testcase-minimized-ffmpeg_BSF_H264_METADATA_fuzzer-6300869057576960 >>> >>> Found-by: continuous fuzzing process >>> https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg >>> Signed-off-by: Michael Niedermayer <mich...@niedermayer.cc> >>> --- >>> libavcodec/h2645_parse.c | 2 +- >>> 1 file changed, 1 insertion(+), 1 deletion(-) >>> >>> diff --git a/libavcodec/h2645_parse.c b/libavcodec/h2645_parse.c >>> index 0f98b49fbe..61105a6eb5 100644 >>> --- a/libavcodec/h2645_parse.c >>> +++ b/libavcodec/h2645_parse.c >>> @@ -467,7 +467,7 @@ int ff_h2645_packet_split(H2645Packet *pkt, const >>> uint8_t *buf, int length, >>> memset(pkt->nals + pkt->nals_allocated, 0, sizeof(*pkt->nals)); >>> >>> nal = &pkt->nals[pkt->nb_nals]; >>> - nal->skipped_bytes_pos_size = 1024; // initial buffer size >>> + nal->skipped_bytes_pos_size = FFMIN(1024, >>> 1+(extract_length>>4)); // initial buffer size >> >> Why is there even an initial buffer? Why not just let >> ff_h2645_extract_rbsp() allocate it when needed? > > i wondered that too and assumed it was done that way to avoid spending > cpu cycles on reallocations later
Many streams don't need to escape bytes, so for those, allocating anything at all is a waste. And IMO by using av_fast_realloc() in ff_h2645_extract_rbsp() there's no need for a big enough initial buffer either. > > > > [...] > > > _______________________________________________ > 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". > _______________________________________________ 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".