diff options
| author | Justin Ruggles <justin.ruggles@gmail.com> | 2012-12-10 12:44:09 -0500 |
|---|---|---|
| committer | Michael Niedermayer <michaelni@gmx.at> | 2013-07-21 01:13:10 +0200 |
| commit | d46713cc7e7dfd88b813078a71ed1c29e42011ca (patch) | |
| tree | a63326df854427052729313f9362d7cd333cca99 | |
| parent | 9c7c2abad4a8eb56472dd5651522530855a62f3f (diff) | |
| download | ffmpeg-d46713cc7e7dfd88b813078a71ed1c29e42011ca.tar.gz | |
swfdec: do better validation of tag length
Avoids trying to read a packet with 0 or negative size.
Avoids a potential infinite loop due to seeking backwards.
Partially based on a patch by Michael Niedermayer.
(cherry picked from commit e70c5b034c4787377e82cab2d5565486baec0c2a)
Conflicts:
libavformat/swfdec.c
| -rw-r--r-- | libavformat/swfdec.c | 20 |
1 files changed, 16 insertions, 4 deletions
diff --git a/libavformat/swfdec.c b/libavformat/swfdec.c index 9a8ef53738..ee1b5960aa 100644 --- a/libavformat/swfdec.c +++ b/libavformat/swfdec.c @@ -154,7 +154,7 @@ static int swf_read_packet(AVFormatContext *s, AVPacket *pkt) if (tag < 0) return tag; if (len < 0) { - av_log(s, AV_LOG_ERROR, "len %d is invalid\n", len); + av_log(s, AV_LOG_ERROR, "invalid tag length: %d\n", len); return AVERROR_INVALIDDATA; } if (tag == TAG_VIDEOSTREAM) { @@ -212,7 +212,10 @@ static int swf_read_packet(AVFormatContext *s, AVPacket *pkt) st = s->streams[i]; if (st->codec->codec_type == AVMEDIA_TYPE_VIDEO && st->id == ch_id) { frame = avio_rl16(pb); - if ((res = av_get_packet(pb, pkt, len-2)) < 0) + len -= 2; + if (len <= 0) + goto skip; + if ((res = av_get_packet(pb, pkt, len)) < 0) return res; pkt->pos = pos; pkt->pts = frame; @@ -226,9 +229,14 @@ static int swf_read_packet(AVFormatContext *s, AVPacket *pkt) if (st->codec->codec_type == AVMEDIA_TYPE_AUDIO && st->id == -1) { if (st->codec->codec_id == AV_CODEC_ID_MP3) { avio_skip(pb, 4); - if ((res = av_get_packet(pb, pkt, len-4)) < 0) + len -= 4; + if (len <= 0) + goto skip; + if ((res = av_get_packet(pb, pkt, len)) < 0) return res; } else { // ADPCM, PCM + if (len <= 0) + goto skip; if ((res = av_get_packet(pb, pkt, len)) < 0) return res; } @@ -254,7 +262,10 @@ static int swf_read_packet(AVFormatContext *s, AVPacket *pkt) st = vst; } avio_rl16(pb); /* BITMAP_ID */ - if ((res = av_new_packet(pkt, len-2)) < 0) + len -= 2; + if (len < 4) + goto skip; + if ((res = av_new_packet(pkt, len)) < 0) return res; avio_read(pb, pkt->data, 4); if (AV_RB32(pkt->data) == 0xffd8ffd9 || @@ -271,6 +282,7 @@ static int swf_read_packet(AVFormatContext *s, AVPacket *pkt) return pkt->size; } skip: + len = FFMAX(0, len); avio_skip(pb, len); } } |