[FFmpeg-cvslog] avcodec/cbs: Allocate more CodedBitstreamUnit at once in cbs_insert_unit()

[Michael Niedermayer]

ffmpeg | branch: release/4.2 | Michael Niedermayer <michael at niedermayer.cc> | Fri Apr 10 22:05:07 2020 +0200| [75df98c0a00aa664e8645a07b7f9ad6760ba6631] | committer: Michael Niedermayer

avcodec/cbs: Allocate more CodedBitstreamUnit at once in cbs_insert_unit()

Fixes: Timeout (85sec -> 0.5sec)
Fixes: 20791/clusterfuzz-testcase-minimized-ffmpeg_BSF_AV1_FRAME_SPLIT_fuzzer-5659537719951360
Fixes: 21214/clusterfuzz-testcase-minimized-ffmpeg_BSF_MPEG2_METADATA_fuzzer-5165560875974656
Fixes: 21247/clusterfuzz-testcase-minimized-ffmpeg_BSF_H264_METADATA_fuzzer-5715175257931776

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
(cherry picked from commit 49ba60fed04d7011c36bae378445ba93ccf983c2)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=75df98c0a00aa664e8645a07b7f9ad6760ba6631
---

 libavcodec/cbs.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/libavcodec/cbs.c b/libavcodec/cbs.c
index 0ce66170ec..0a71385fa2 100644
--- a/libavcodec/cbs.c
+++ b/libavcodec/cbs.c
@@ -693,11 +693,11 @@ static int cbs_insert_unit(CodedBitstreamContext *ctx,
             memmove(units + position + 1, units + position,
                     (frag->nb_units - position) * sizeof(*units));
     } else {
-        units = av_malloc_array(frag->nb_units + 1, sizeof(*units));
+        units = av_malloc_array(frag->nb_units*2 + 1, sizeof(*units));
         if (!units)
             return AVERROR(ENOMEM);
 
-        ++frag->nb_units_allocated;
+        frag->nb_units_allocated = 2*frag->nb_units_allocated + 1;
 
         if (position > 0)
             memcpy(units, frag->units, position * sizeof(*units));