[FFmpeg-cvslog] avcodec/vc1_block: Check for end of bitstream at the top of vc1_decode_i_blocks_adv()
Michael Niedermayer
git at videolan.org
Sat Nov 9 18:10:20 EET 2019
ffmpeg | branch: master | Michael Niedermayer <michael at niedermayer.cc> | Sat Sep 28 22:44:18 2019 +0200| [947732c56d56a567f051cfd8219678372230ce70] | committer: Michael Niedermayer
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 at niedermayer.cc>
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=947732c56d56a567f051cfd8219678372230ce70
---
libavcodec/vc1_block.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/libavcodec/vc1_block.c b/libavcodec/vc1_block.c
index 4c6dfaf6bf..ca793a7992 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)
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