[FFmpeg-cvslog] avcodec/mpeg4videodec: Check read profile before setting it
Michael Niedermayer
git at videolan.org
Thu Jun 28 22:37:33 EEST 2018
ffmpeg | branch: master | Michael Niedermayer <michael at niedermayer.cc> | Wed Jun 27 19:37:09 2018 +0200| [2aa9047486dbff12d9e040f917e5f799ed2fd78b] | committer: Michael Niedermayer
avcodec/mpeg4videodec: Check read profile before setting it
Fixes: null pointer dereference
Fixes: ffmpeg_crash_7.avi
Found-by: Thuan Pham, Marcel Böhme, Andrew Santosa and Alexandru Razvan Caciulescu with AFLSmart
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=2aa9047486dbff12d9e040f917e5f799ed2fd78b
---
libavcodec/mpeg4videodec.c | 23 +++++++++++++++--------
1 file changed, 15 insertions(+), 8 deletions(-)
diff --git a/libavcodec/mpeg4videodec.c b/libavcodec/mpeg4videodec.c
index d0ebaac6e8..54a8496244 100644
--- a/libavcodec/mpeg4videodec.c
+++ b/libavcodec/mpeg4videodec.c
@@ -1980,15 +1980,15 @@ static int mpeg4_decode_gop_header(MpegEncContext *s, GetBitContext *gb)
return 0;
}
-static int mpeg4_decode_profile_level(MpegEncContext *s, GetBitContext *gb)
+static int mpeg4_decode_profile_level(MpegEncContext *s, GetBitContext *gb, int *profile, int *level)
{
- s->avctx->profile = get_bits(gb, 4);
- s->avctx->level = get_bits(gb, 4);
+ *profile = get_bits(gb, 4);
+ *level = get_bits(gb, 4);
// for Simple profile, level 0
- if (s->avctx->profile == 0 && s->avctx->level == 8) {
- s->avctx->level = 0;
+ if (*profile == 0 && *level == 8) {
+ *level = 0;
}
return 0;
@@ -3211,13 +3211,19 @@ int ff_mpeg4_decode_picture_header(Mpeg4DecContext *ctx, GetBitContext *gb)
} else if (startcode == GOP_STARTCODE) {
mpeg4_decode_gop_header(s, gb);
} else if (startcode == VOS_STARTCODE) {
- mpeg4_decode_profile_level(s, gb);
- if (s->avctx->profile == FF_PROFILE_MPEG4_SIMPLE_STUDIO &&
- (s->avctx->level > 0 && s->avctx->level < 9)) {
+ int profile, level;
+ mpeg4_decode_profile_level(s, gb, &profile, &level);
+ if (profile == FF_PROFILE_MPEG4_SIMPLE_STUDIO &&
+ (level > 0 && level < 9)) {
s->studio_profile = 1;
next_start_code_studio(gb);
extension_and_user_data(s, gb, 0);
+ } else if (s->studio_profile) {
+ avpriv_request_sample(s->avctx, "Mixes studio and non studio profile\n");
+ return AVERROR_PATCHWELCOME;
}
+ s->avctx->profile = profile;
+ s->avctx->level = level;
} else if (startcode == VISUAL_OBJ_STARTCODE) {
if (s->studio_profile) {
if ((ret = decode_studiovisualobject(ctx, gb)) < 0)
@@ -3238,6 +3244,7 @@ end:
s->avctx->has_b_frames = !s->low_delay;
if (s->studio_profile) {
+ av_assert0(s->avctx->profile == FF_PROFILE_MPEG4_SIMPLE_STUDIO);
if (!s->avctx->bits_per_raw_sample) {
av_log(s->avctx, AV_LOG_ERROR, "Missing VOL header\n");
return AVERROR_INVALIDDATA;
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