From 4cc3467e7abfea7e8d03b6af511f7719038a5a98 Mon Sep 17 00:00:00 2001 From: Chris Evans Date: Wed, 29 Jun 2011 15:44:40 -0700 Subject: [PATCH] oggdec: prevent heap corruption. Specifically crafted samples can reinit ogg->streams[] while reading samples, and thus we should not cache old pointers since these may no longer be valid. Signed-off-by: Ronald S. Bultje --- libavformat/oggdec.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/libavformat/oggdec.c b/libavformat/oggdec.c index e33de7d978..3d03a5f974 100644 --- a/libavformat/oggdec.c +++ b/libavformat/oggdec.c @@ -592,15 +592,15 @@ static int64_t ogg_read_timestamp(AVFormatContext *s, int stream_index, int64_t *pos_arg, int64_t pos_limit) { struct ogg *ogg = s->priv_data; - struct ogg_stream *os = ogg->streams + stream_index; AVIOContext *bc = s->pb; int64_t pts = AV_NOPTS_VALUE; - int i; + int i = -1; avio_seek(bc, *pos_arg, SEEK_SET); ogg_reset(ogg); while (avio_tell(bc) < pos_limit && !ogg_packet(s, &i, NULL, NULL, pos_arg)) { if (i == stream_index) { + struct ogg_stream *os = ogg->streams + stream_index; pts = ogg_calc_pts(s, i, NULL); if (os->keyframe_seek && !(os->pflags & AV_PKT_FLAG_KEY)) pts = AV_NOPTS_VALUE; @@ -626,6 +626,7 @@ static int ogg_read_seek(AVFormatContext *s, int stream_index, os->keyframe_seek = 1; ret = av_seek_frame_binary(s, stream_index, timestamp, flags); + os = ogg->streams + stream_index; if (ret < 0) os->keyframe_seek = 0; return ret;