avcodec/vc1_block: Check get_vlc2() return before use

Fixes: index -1 out of bounds for type 'const uint8_t [185][2]'
Fixes: 15720/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_MSS2_fuzzer-5666071933091840

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 2cb1f79735)
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
This commit is contained in:
Michael Niedermayer 2019-08-04 08:32:58 +02:00
parent 25aa7ddd31
commit 889fdc690a
1 changed files with 2 additions and 0 deletions

View File

@ -526,6 +526,8 @@ static int vc1_decode_ac_coeff(VC1Context *v, int *last, int *skip,
int escape = decode210(gb);
if (escape != 2) {
index = get_vlc2(gb, ff_vc1_ac_coeff_table[codingset].table, AC_VLC_BITS, 3);
if (index < 0)
return AVERROR_INVALIDDATA;
run = vc1_index_decode_table[codingset][index][0];
level = vc1_index_decode_table[codingset][index][1];
lst = index >= vc1_last_decode_table[codingset];