From 947732c56d56a567f051cfd8219678372230ce70 Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Sat, 28 Sep 2019 22:44:18 +0200 Subject: avcodec/vc1_block: Check for end of bitstream at the top of vc1_decode_i_blocks_adv() Fixes: Timeout (147sec -> 2sec) Fixes: 17704/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_VC1IMAGE_fuzzer-5723851098423296 Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg Signed-off-by: Michael Niedermayer --- libavcodec/vc1_block.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) (limited to 'libavcodec') diff --git a/libavcodec/vc1_block.c b/libavcodec/vc1_block.c index 4c6dfaf..ca793a7 100644 --- a/libavcodec/vc1_block.c +++ b/libavcodec/vc1_block.c @@ -2661,7 +2661,7 @@ static void vc1_decode_i_blocks(VC1Context *v) /** Decode blocks of I-frame for advanced profile */ -static void vc1_decode_i_blocks_adv(VC1Context *v) +static int vc1_decode_i_blocks_adv(VC1Context *v) { int k; MpegEncContext *s = &v->s; @@ -2672,6 +2672,9 @@ static void vc1_decode_i_blocks_adv(VC1Context *v) int mqdiff; GetBitContext *gb = &s->gb; + if (get_bits_left(gb) <= 1) + return AVERROR_INVALIDDATA; + /* select coding mode used for VLC tables selection */ switch (v->y_ac_table_index) { case 0: @@ -2775,7 +2778,7 @@ static void vc1_decode_i_blocks_adv(VC1Context *v) ff_er_add_slice(&s->er, 0, s->start_mb_y, s->mb_x, s->mb_y, ER_MB_ERROR); av_log(s->avctx, AV_LOG_ERROR, "Bits overconsumption: %i > %i\n", get_bits_count(&s->gb), v->bits); - return; + return 0; } inc_blk_idx(v->topleft_blk_idx); inc_blk_idx(v->top_blk_idx); @@ -2793,6 +2796,7 @@ static void vc1_decode_i_blocks_adv(VC1Context *v) ff_mpeg_draw_horiz_band(s, (s->end_mb_y - 1) * 16, 16); ff_er_add_slice(&s->er, 0, s->start_mb_y << v->field_mode, s->mb_width - 1, (s->end_mb_y << v->field_mode) - 1, ER_MB_END); + return 0; } static void vc1_decode_p_blocks(VC1Context *v) -- cgit v1.1