[FFmpeg-devel] [PATCH] Fix double free and null dereferences in the qsv decoder

[Ivan Uskov]

Hello Yuli,

Wednesday, July 27, 2016, 6:21:41 PM, you wrote:

> 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>
> ---
>  libavcodec/qsvdec.c | 10 ++++++----
>  1 file changed, 6 insertions(+), 4 deletions(-)

> diff --git a/libavcodec/qsvdec.c b/libavcodec/qsvdec.c
> index 9125700..b462887 100644
> --- a/libavcodec/qsvdec.c
> +++ b/libavcodec/qsvdec.c
> @@ -408,7 +408,7 @@ static int do_qsv_decode(AVCodecContext *avctx, QSVContext *q,
>          return ff_qsv_error(ret);
>      }
>      n_out_frames = av_fifo_size(q->async_fifo) / (sizeof(out_frame)+sizeof(sync));
> -
> +    av_freep(&sync);
I'm sorry but it is not actual more. There was the roll-back for
sync allocations on heap at July 24, now there is old good way uses again.

>      if (n_out_frames > q->async_depth || (flush && n_out_frames) ) {
>          AVFrame *src_frame;
>  
> @@ -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)


-- 
Best regards,
 Ivan                            mailto:ivan.uskov at nablet.com