[FFmpeg-cvslog] avcodec/wmv2dec: Check end of bitstream in parse_mb_skip() and ff_wmv2_decode_mb()
Michael Niedermayer
git at videolan.org
Sat Nov 18 12:58:48 EET 2017
ffmpeg | branch: master | Michael Niedermayer <michael at niedermayer.cc> | Sun Sep 17 01:28:07 2017 +0200| [65e0a7c473f23f1833538ffecf53c81fe500b5e4] | committer: Michael Niedermayer
avcodec/wmv2dec: Check end of bitstream in parse_mb_skip() and ff_wmv2_decode_mb()
Fixes: Timeout
Fixes: 3200/clusterfuzz-testcase-5750022136135680
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=65e0a7c473f23f1833538ffecf53c81fe500b5e4
---
libavcodec/wmv2dec.c | 18 ++++++++++++++++--
1 file changed, 16 insertions(+), 2 deletions(-)
diff --git a/libavcodec/wmv2dec.c b/libavcodec/wmv2dec.c
index 261d291c97..ea0e0594b5 100644
--- a/libavcodec/wmv2dec.c
+++ b/libavcodec/wmv2dec.c
@@ -30,7 +30,7 @@
#include "wmv2.h"
-static void parse_mb_skip(Wmv2Context *w)
+static int parse_mb_skip(Wmv2Context *w)
{
int mb_x, mb_y;
MpegEncContext *const s = &w->s;
@@ -45,6 +45,8 @@ static void parse_mb_skip(Wmv2Context *w)
MB_TYPE_16x16 | MB_TYPE_L0;
break;
case SKIP_TYPE_MPEG:
+ if (get_bits_left(&s->gb) < s->mb_height * s->mb_width)
+ return AVERROR_INVALIDDATA;
for (mb_y = 0; mb_y < s->mb_height; mb_y++)
for (mb_x = 0; mb_x < s->mb_width; mb_x++)
mb_type[mb_y * s->mb_stride + mb_x] =
@@ -52,6 +54,8 @@ static void parse_mb_skip(Wmv2Context *w)
break;
case SKIP_TYPE_ROW:
for (mb_y = 0; mb_y < s->mb_height; mb_y++) {
+ if (get_bits_left(&s->gb) < 1)
+ return AVERROR_INVALIDDATA;
if (get_bits1(&s->gb)) {
for (mb_x = 0; mb_x < s->mb_width; mb_x++)
mb_type[mb_y * s->mb_stride + mb_x] =
@@ -65,6 +69,8 @@ static void parse_mb_skip(Wmv2Context *w)
break;
case SKIP_TYPE_COL:
for (mb_x = 0; mb_x < s->mb_width; mb_x++) {
+ if (get_bits_left(&s->gb) < 1)
+ return AVERROR_INVALIDDATA;
if (get_bits1(&s->gb)) {
for (mb_y = 0; mb_y < s->mb_height; mb_y++)
mb_type[mb_y * s->mb_stride + mb_x] =
@@ -77,6 +83,7 @@ static void parse_mb_skip(Wmv2Context *w)
}
break;
}
+ return 0;
}
static int decode_ext_header(Wmv2Context *w)
@@ -170,9 +177,12 @@ int ff_wmv2_decode_secondary_picture_header(MpegEncContext *s)
}
} else {
int cbp_index;
+ int ret;
w->j_type = 0;
- parse_mb_skip(w);
+ ret = parse_mb_skip(w);
+ if (ret < 0)
+ return ret;
cbp_index = decode012(&s->gb);
w->cbp_table_index = wmv2_get_cbp_table_index(s, cbp_index);
@@ -359,6 +369,8 @@ int ff_wmv2_decode_mb(MpegEncContext *s, int16_t block[6][64])
w->hshift = 0;
return 0;
}
+ if (get_bits_left(&s->gb) <= 0)
+ return AVERROR_INVALIDDATA;
code = get_vlc2(&s->gb, ff_mb_non_intra_vlc[w->cbp_table_index].table,
MB_NON_INTRA_VLC_BITS, 3);
@@ -369,6 +381,8 @@ int ff_wmv2_decode_mb(MpegEncContext *s, int16_t block[6][64])
cbp = code & 0x3f;
} else {
s->mb_intra = 1;
+ if (get_bits_left(&s->gb) <= 0)
+ return AVERROR_INVALIDDATA;
code = get_vlc2(&s->gb, ff_msmp4_mb_i_vlc.table, MB_INTRA_VLC_BITS, 2);
if (code < 0) {
av_log(s->avctx, AV_LOG_ERROR,
More information about the ffmpeg-cvslog
mailing list