[FFmpeg-devel] [PATCH 1/2] lavc/qsvenc: Fix the memory leak for enc_ctrl.Payload

[Li, Zhong]

> From: ffmpeg-devel [mailto:ffmpeg-devel-bounces at ffmpeg.org] On Behalf
> Of Linjie Fu
> Sent: Wednesday, April 10, 2019 7:27 PM
> To: ffmpeg-devel at ffmpeg.org
> Cc: Fu, Linjie <linjie.fu at intel.com>
> Subject: [FFmpeg-devel] [PATCH 1/2] lavc/qsvenc: Fix the memory leak for
> enc_ctrl.Payload
> 
> frame->enc_ctrl.Payload is malloced in get_free_frame, directly memset
> the whole structure of enc_ctrl to zero will cause the memory leak for
> enc_ctrl.Payload.
> 
> Fix the memory leak issue and reset other members in mfxEncodeCtrl.
> 
> Signed-off-by: Linjie Fu <linjie.fu at intel.com>
> ---
>  libavcodec/qsvenc.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/libavcodec/qsvenc.c b/libavcodec/qsvenc.c index
> 5aa020d47b..029bb562d6 100644
> --- a/libavcodec/qsvenc.c
> +++ b/libavcodec/qsvenc.c
> @@ -1254,7 +1254,7 @@ static int encode_frame(AVCodecContext *avctx,
> QSVEncContext *q,
>      if (qsv_frame) {
>          surf = &qsv_frame->surface;
>          enc_ctrl = &qsv_frame->enc_ctrl;
> -        memset(enc_ctrl, 0, sizeof(mfxEncodeCtrl));
> +        memset(enc_ctrl, 0, sizeof(mfxEncodeCtrl) - sizeof(mfxPayload
> + **));

Looks a little tricky, if someone didn't read carefully the sequence of mfxPayload usages, they can't know why this change happening. 
And potential risk for other elements such as "mfxExtBuffer** ExtParam" is still existed. 

IMHO, one good habit is that is you want to memset a buffer, would better memset it when you allocate it. 
So I believe the correct fix should be: memset mfxEncodeCtrl at the start of qsv frame allocated: the place should be in the function get_free_frame()