[FFmpeg-cvslog] avformat/mpc8: Check first keyframe position for overflow
Michael Niedermayer
git at videolan.org
Wed Sep 8 22:43:48 EEST 2021
ffmpeg | branch: release/4.4 | Michael Niedermayer <michael at niedermayer.cc> | Sun Aug 1 20:25:20 2021 +0200| [58477f42a2a7220bf412fbfd460c6fcc077396a5] | committer: Michael Niedermayer
avformat/mpc8: Check first keyframe position for overflow
Fixes: signed integer overflow: 9223372036854775791 + 18 cannot be represented in type 'long'
Fixes: 36307/clusterfuzz-testcase-minimized-ffmpeg_dem_MPC8_fuzzer-4917863877050368
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 2bbef69b0ba938cce4f9d61bed46d3f3058e56c2)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=58477f42a2a7220bf412fbfd460c6fcc077396a5
---
libavformat/mpc8.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/libavformat/mpc8.c b/libavformat/mpc8.c
index 95813df748..c3d7e115a7 100644
--- a/libavformat/mpc8.c
+++ b/libavformat/mpc8.c
@@ -177,7 +177,13 @@ static void mpc8_parse_seektable(AVFormatContext *s, int64_t off)
}
seekd = get_bits(&gb, 4);
for(i = 0; i < 2; i++){
- pos = gb_get_v(&gb) + c->header_pos;
+ pos = gb_get_v(&gb);
+ if (av_sat_add64(pos, c->header_pos) != pos + (uint64_t)c->header_pos) {
+ av_free(buf);
+ return;
+ }
+
+ pos += c->header_pos;
ppos[1 - i] = pos;
av_add_index_entry(s->streams[0], pos, i, 0, 0, AVINDEX_KEYFRAME);
}
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