From 51dd54c51aaca909893c9f90a4119e96ff71ffdf Mon Sep 17 00:00:00 2001 From: Xiaohan Wang Date: Thu, 6 Nov 2014 12:59:54 -0800 Subject: [PATCH] matroskadec: Fix read-after-free in matroska_read_seek() In matroska_read_seek(), |tracks| is assigned at the begining of the function. However, functions like matroska_parse_cues() could reallocate the tracks and invalidate |tracks|. This assigns |tracks| only before using it, so that it will not get invalidated elsewhere. Bug-Id: chromium/427266 --- libavformat/matroskadec.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/libavformat/matroskadec.c b/libavformat/matroskadec.c index 922b2580be..4dd82d214a 100644 --- a/libavformat/matroskadec.c +++ b/libavformat/matroskadec.c @@ -1974,7 +1974,7 @@ static int matroska_read_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags) { MatroskaDemuxContext *matroska = s->priv_data; - MatroskaTrack *tracks = matroska->tracks.elem; + MatroskaTrack *tracks = NULL; AVStream *st = s->streams[stream_index]; int i, index, index_sub, index_min; @@ -2003,6 +2003,7 @@ static int matroska_read_seek(AVFormatContext *s, int stream_index, return 0; index_min = index; + tracks = matroska->tracks.elem; for (i=0; i < matroska->tracks.nb_elem; i++) { tracks[i].audio.pkt_cnt = 0; tracks[i].audio.sub_packet_cnt = 0;