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authorMichael Niedermayer <michael@niedermayer.cc>2021-04-24 17:42:19 +0200
committerMichael Niedermayer <michael@niedermayer.cc>2021-10-06 14:41:41 +0200
commited9fe15b4928f4f0358e978b9c315f590bc909e5 (patch)
tree42f9fc7dc5296bfd25e580e1e3018237ec25b5f6
parent433e72f7e579a065de1d1811d9e2be4faec99b5f (diff)
downloadffmpeg-ed9fe15b4928f4f0358e978b9c315f590bc909e5.tar.gz
avformat/mpc8: Check for position overflow in mpc8_handle_chunk()
Fixes: signed integer overflow: 15 + 9223372036854775796 cannot be represented in type 'long' Fixes: 29102/clusterfuzz-testcase-minimized-ffmpeg_dem_MPC8_fuzzer-6723520756318208 Fixes: 29102/clusterfuzz-testcase-minimized-ffmpeg_dem_MPC8_fuzzer-6739833034768384 Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg Signed-off-by: Michael Niedermayer <michael@niedermayer.cc> (cherry picked from commit 8ef25d118246bf443900033fb3588dba628d11b0) Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
-rw-r--r--libavformat/mpc8.c5
1 files changed, 4 insertions, 1 deletions
diff --git a/libavformat/mpc8.c b/libavformat/mpc8.c
index 88c55e3d22..95813df748 100644
--- a/libavformat/mpc8.c
+++ b/libavformat/mpc8.c
@@ -205,8 +205,11 @@ static void mpc8_handle_chunk(AVFormatContext *s, int tag, int64_t chunk_pos, in
switch(tag){
case TAG_SEEKTBLOFF:
- pos = avio_tell(pb) + size;
+ pos = avio_tell(pb);
off = ffio_read_varlen(pb);
+ if (pos > INT64_MAX - size || off < 0 || off > INT64_MAX - chunk_pos)
+ return;
+ pos += size;
mpc8_parse_seektable(s, chunk_pos + off);
avio_seek(pb, pos, SEEK_SET);
break;