[FFmpeg-cvslog] avcodec/qsvdec: Fix null dereferences in the qsv decoder

[Yuli Khodorkovskiy]

ffmpeg | branch: master | Yuli Khodorkovskiy <ykhodo at gmail.com> | Fri Jul 29 11:00:44 2016 -0400| [f0adb99d068e659178c00271a46cd469dfc01a6e] | committer: Michael Niedermayer

avcodec/qsvdec: Fix null dereferences in the qsv decoder

This patch fixes the h264_qsv decoder issues mentioned
in https://ffmpeg.zeranoe.com/forum/viewtopic.php?t=2962.

The patch may be tested by specifying h264_qsv as the decoder to ffplay
for an h264 encoded file.

	ffplay -vcodec h264_qsv foo.mts

Signed-off-by: Yuli Khodorkovskiy <ykhodo at gmail.com>
Push requested-by: Ivan Uskov
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=f0adb99d068e659178c00271a46cd469dfc01a6e
---

 libavcodec/qsvdec.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/libavcodec/qsvdec.c b/libavcodec/qsvdec.c
index 9125700..98585e3 100644
--- a/libavcodec/qsvdec.c
+++ b/libavcodec/qsvdec.c
@@ -555,16 +555,18 @@ void ff_qsv_decode_reset(AVCodecContext *avctx, QSVContext *q)
     }
 
     /* Reset output surfaces */
-    av_fifo_reset(q->async_fifo);
+    if (q->async_fifo)
+        av_fifo_reset(q->async_fifo);
 
     /* Reset input packets fifo */
-    while (av_fifo_size(q->pkt_fifo)) {
+    while (q->pkt_fifo && av_fifo_size(q->pkt_fifo)) {
         av_fifo_generic_read(q->pkt_fifo, &pkt, sizeof(pkt), NULL);
         av_packet_unref(&pkt);
     }
 
     /* Reset input bitstream fifo */
-    av_fifo_reset(q->input_fifo);
+    if (q->input_fifo)
+        av_fifo_reset(q->input_fifo);
 }
 
 int ff_qsv_decode_close(QSVContext *q)