[FFmpeg-devel] [PATCH] avcodec/frame_thread_encoder: Free AVCodecContext structure on error during init

[James Almer]

On 8/13/2021 2:48 PM, Michael Niedermayer wrote:
> Fixes: MemLeak
> Fixes: 8281
> Fixes: PoC_option158.jpg
> Fixes: CVE-2020-22037
> 
> Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
> ---
>   libavcodec/frame_thread_encoder.c | 10 ++++++----
>   1 file changed, 6 insertions(+), 4 deletions(-)
> 
> diff --git a/libavcodec/frame_thread_encoder.c b/libavcodec/frame_thread_encoder.c
> index 9cabfc495f..25a308173d 100644
> --- a/libavcodec/frame_thread_encoder.c
> +++ b/libavcodec/frame_thread_encoder.c
> @@ -126,7 +126,7 @@ int ff_frame_thread_encoder_init(AVCodecContext *avctx)
>   {
>       int i=0;
>       ThreadContext *c;
> -
> +    AVCodecContext *thread_avctx = NULL;
>   
>       if(   !(avctx->thread_type & FF_THREAD_FRAME)
>          || !(avctx->codec->capabilities & AV_CODEC_CAP_FRAME_THREADS))
> @@ -202,16 +202,16 @@ int ff_frame_thread_encoder_init(AVCodecContext *avctx)
>       for(i=0; i<avctx->thread_count ; i++){
>           int ret;
>           void *tmpv;
> -        AVCodecContext *thread_avctx = avcodec_alloc_context3(avctx->codec);
> +        thread_avctx = avcodec_alloc_context3(avctx->codec);
>           if(!thread_avctx)
>               goto fail;
>           tmpv = thread_avctx->priv_data;
>           *thread_avctx = *avctx;
> +        thread_avctx->priv_data = tmpv;
> +        thread_avctx->internal = NULL;
>           ret = av_opt_copy(thread_avctx, avctx);
>           if (ret < 0)
>               goto fail;
> -        thread_avctx->priv_data = tmpv;
> -        thread_avctx->internal = NULL;
>           if (avctx->codec->priv_class) {
>               int ret = av_opt_copy(thread_avctx->priv_data, avctx->priv_data);
>               if (ret < 0)
> @@ -233,6 +233,8 @@ int ff_frame_thread_encoder_init(AVCodecContext *avctx)
>   
>       return 0;
>   fail:
> +    avcodec_close(thread_avctx);
> +    av_freep(&thread_avctx);
>       avctx->thread_count = i;
>       av_log(avctx, AV_LOG_ERROR, "ff_frame_thread_encoder_init failed\n");
>       ff_frame_thread_encoder_free(avctx);

Should be ok.