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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 <michael@niedermayer.cc>
This commit is contained in:
Michael Niedermayer 2019-09-28 22:44:18 +02:00
parent de1d3b0925
commit 947732c56d

View File

@ -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)