Fix leaking of side data.

While we correctly "register" the side data when we split it,
the application (in this case FFmpeg) might not update the
AVPacket pool it uses to finally free the packet, thus
causing a leak.
This also makes the av_dup_packet unnecessary which could
cause an even worse leak in this situation.
Also change the code to not modify the user-provide AVPacket at all.

Signed-off-by: Reimar Döffinger <Reimar.Doeffinger@gmx.de>

1 files changed, 11 insertions, 6 deletions

diff --git a/libavcodec/utils.c b/libavcodec/utils.c
index 219be6b7fb..e25f1dfb41 100644
--- a/libavcodec/utils.c
+++ b/libavcodec/utils.c
@@ -994,24 +994,26 @@ static void apply_param_change(AVCodecContext *avctx, AVPacket *avpkt)
 
 int attribute_align_arg avcodec_decode_video2(AVCodecContext *avctx, AVFrame *picture,
                          int *got_picture_ptr,
-                         AVPacket *avpkt)
+                         const AVPacket *avpkt)
 {
     int ret;
+    // copy to ensure we do not change avpkt
+    AVPacket tmp = *avpkt;
 
     *got_picture_ptr= 0;
     if((avctx->coded_width||avctx->coded_height) && av_image_check_size(avctx->coded_width, avctx->coded_height, 0, avctx))
         return -1;
 
     if((avctx->codec->capabilities & CODEC_CAP_DELAY) || avpkt->size || (avctx->active_thread_type&FF_THREAD_FRAME)){
-        av_packet_split_side_data(avpkt);
-        apply_param_change(avctx, avpkt);
-        avctx->pkt = avpkt;
+        int did_split = av_packet_split_side_data(&tmp);
+        apply_param_change(avctx, &tmp);
+        avctx->pkt = &tmp;
         if (HAVE_THREADS && avctx->active_thread_type&FF_THREAD_FRAME)
              ret = ff_thread_decode_frame(avctx, picture, got_picture_ptr,
-                                          avpkt);
+                                          &tmp);
         else {
             ret = avctx->codec->decode(avctx, picture, got_picture_ptr,
-                              avpkt);
+                              &tmp);
             picture->pkt_dts= avpkt->dts;
 
             if(!avctx->has_b_frames){
@@ -1030,6 +1032,9 @@ int attribute_align_arg avcodec_decode_video2(AVCodecContext *avctx, AVFrame *pi
 
         emms_c(); //needed to avoid an emms_c() call before every return;
 
+        avctx->pkt = NULL;
+        if (did_split)
+            ff_packet_free_side_data(&tmp);
 
         if (*got_picture_ptr){
             avctx->frame_number++;