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lavf/mov: ensure only one tkhd per trak 

Chromium fuzzing produced a whacky file with extra tkhds. This caused
an AVStream that was already in use to be corrupted by assigning it a
new id, which blows up later in mov_read_trun because the
MOVFragmentStreamInfo.index_entry now points OOB.

Reviewed-by: Baptiste Coudurier <baptiste.coudurier@gmail.com>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
This commit is contained in:
chcunningham 2018-12-13 13:58:40 -08:00 committed by Michael Niedermayer
parent 436bffaca2
commit c9f7b6f7a9
1 changed files with 11 additions and 1 deletions
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12
libavformat/mov.c
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@ -1326,6 +1326,10 @@ static int update_frag_index(MOVContext *c, int64_t offset)
return -1;
for (i = 0; i < c->fc->nb_streams; i++) {
// Avoid building frag index if streams lack track id.
if (c->fc->streams[i]->id < 0)
return AVERROR_INVALIDDATA;
frag_stream_info[i].id = c->fc->streams[i]->id;
frag_stream_info[i].sidx_pts = AV_NOPTS_VALUE;
frag_stream_info[i].tfdt_dts = AV_NOPTS_VALUE;
@ -4154,7 +4158,7 @@ static int mov_read_trak(MOVContext *c, AVIOContext *pb, MOVAtom atom)
st = avformat_new_stream(c->fc, NULL);
if (!st) return AVERROR(ENOMEM);
st->id = c->fc->nb_streams;
st->id = -1;
sc = av_mallocz(sizeof(MOVStreamContext));
if (!sc) return AVERROR(ENOMEM);
@ -4438,6 +4442,11 @@ static int mov_read_tkhd(MOVContext *c, AVIOContext *pb, MOVAtom atom)
st = c->fc->streams[c->fc->nb_streams-1];
sc = st->priv_data;
// Each stream (trak) should have exactly 1 tkhd. This catches bad files and
// avoids corrupting AVStreams mapped to an earlier tkhd.
if (st->id != -1)
return AVERROR_INVALIDDATA;
version = avio_r8(pb);
flags = avio_rb24(pb);
st->disposition |= (flags & MOV_TKHD_FLAG_ENABLED) ? AV_DISPOSITION_DEFAULT : 0;
@ -4704,6 +4713,7 @@ static int mov_read_trun(MOVContext *c, AVIOContext *pb, MOVAtom atom)
break;
}
}
av_assert0(index_entry_pos <= st->nb_index_entries);
avio_r8(pb); /* version */
flags = avio_rb24(pb);