From e5ce10514918cec2ca25cf48e0dcc80d68e18656 Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Wed, 1 May 2019 00:40:03 +0200 Subject: [PATCH] avcodec/wmv2dec: Check input bits vs. coded MBs Fixes: Timeout (94sec ->8sec) Fixes: 14387/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_WMV2_fuzzer-5723546887651328 Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg Signed-off-by: Michael Niedermayer --- libavcodec/wmv2dec.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/libavcodec/wmv2dec.c b/libavcodec/wmv2dec.c index 124dfdb7e0..afa65478e3 100644 --- a/libavcodec/wmv2dec.c +++ b/libavcodec/wmv2dec.c @@ -33,6 +33,7 @@ static int parse_mb_skip(Wmv2Context *w) { int mb_x, mb_y; + int coded_mb_count = 0; MpegEncContext *const s = &w->s; uint32_t *const mb_type = s->current_picture_ptr->mb_type; @@ -83,6 +84,14 @@ static int parse_mb_skip(Wmv2Context *w) } break; } + + for (mb_y = 0; mb_y < s->mb_height; mb_y++) + for (mb_x = 0; mb_x < s->mb_width; mb_x++) + coded_mb_count += !IS_SKIP(mb_type[mb_y * s->mb_stride + mb_x]); + + if (coded_mb_count > get_bits_left(&s->gb)) + return AVERROR_INVALIDDATA; + return 0; }