[FFmpeg-devel] [PATCH] avformat/asfdec: fix crash caused by free wlid pointers

Yang Xiao yshaw1999 at 163.com
Tue Jan 11 08:38:56 EET 2022


From: Yang Xiao <yshaw99 at outlook.com>

This commit fixed a crash when seeking wma frames, asf decoder will try to demux in function asf_read_pts().
Pointer member side_data of AVPacket that allocated by stack may be wild pointer.
Prevent releasing wild pointers in AVPacket when some functions try to call av_packet_unref, example av_read_frame().
---
 libavformat/asfdec_f.c | 2 +-
 libavformat/mpc.c      | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/libavformat/asfdec_f.c b/libavformat/asfdec_f.c
index a8f36ed286..bae0ecfc7c 100644
--- a/libavformat/asfdec_f.c
+++ b/libavformat/asfdec_f.c
@@ -1433,7 +1433,7 @@ static int64_t asf_read_pts(AVFormatContext *s, int stream_index,
 {
     FFFormatContext *const si = ffformatcontext(s);
     ASFContext *asf     = s->priv_data;
-    AVPacket pkt1, *pkt = &pkt1;
+    AVPacket pkt1 = {0}, *pkt = &pkt1;
     ASFStream *asf_st;
     int64_t pts;
     int64_t pos = *ppos;
diff --git a/libavformat/mpc.c b/libavformat/mpc.c
index b5b2bab33c..ad0d693152 100644
--- a/libavformat/mpc.c
+++ b/libavformat/mpc.c
@@ -189,7 +189,7 @@ static int mpc_read_seek(AVFormatContext *s, int stream_index, int64_t timestamp
     AVStream *st = s->streams[stream_index];
     FFStream *const sti = ffstream(st);
     MPCContext *c = s->priv_data;
-    AVPacket pkt1, *pkt = &pkt1;
+    AVPacket pkt1 = {0}, *pkt = &pkt1;
     int ret;
     int index = av_index_search_timestamp(st, FFMAX(timestamp - DELAY_FRAMES, 0), flags);
     uint32_t lastframe;
-- 
2.30.1 (Apple Git-130)



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