avcodec/smacker: Check remaining bits in SMK_BLK_FULL

Fixes: out of array access
Fixes: 26047/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_SMACKER_fuzzer-5083031667474432

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
This commit is contained in:
Michael Niedermayer 2020-10-02 10:54:31 +02:00
parent 5a2a7604da
commit 42ded4d1e6
1 changed files with 2 additions and 0 deletions

View File

@ -448,6 +448,8 @@ static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
case SMK_BLK_FULL: case SMK_BLK_FULL:
mode = 0; mode = 0;
if(avctx->codec_tag == MKTAG('S', 'M', 'K', '4')) { // In case of Smacker v4 we have three modes if(avctx->codec_tag == MKTAG('S', 'M', 'K', '4')) { // In case of Smacker v4 we have three modes
if (get_bits_left(&gb) < 1)
return AVERROR_INVALIDDATA;
if(get_bits1(&gb)) mode = 1; if(get_bits1(&gb)) mode = 1;
else if(get_bits1(&gb)) mode = 2; else if(get_bits1(&gb)) mode = 2;
} }