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avcodec/mpeg4videodec: Check read profile before setting it

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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@niedermayer.cc>
This commit is contained in:
Michael Niedermayer 2018-06-27 19:37:09 +02:00
parent 95556e27e2
commit 2aa9047486
1 changed files with 15 additions and 8 deletions
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23
libavcodec/mpeg4videodec.c
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@ -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;