[FFmpeg-devel] [PATCH 2/4] avcodec/vp5: Check render_x/y

[Peter Ross]

On Wed, Oct 23, 2019 at 08:57:12PM +0200, Michael Niedermayer wrote:
> Fixes: Timeout (15sec -> 91ms)
> Fixes: 18353/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_VP5_fuzzer-5704150326706176
> 
> Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
> Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
> ---
>  libavcodec/vp5.c | 9 +++++++--
>  1 file changed, 7 insertions(+), 2 deletions(-)
> 
> diff --git a/libavcodec/vp5.c b/libavcodec/vp5.c
> index 0fca282918..f3946f508c 100644
> --- a/libavcodec/vp5.c
> +++ b/libavcodec/vp5.c
> @@ -48,6 +48,8 @@ static int vp5_parse_header(VP56Context *s, const uint8_t *buf, int buf_size)
>      ff_vp56_init_dequant(s, vp56_rac_gets(c, 6));
>      if (s->frames[VP56_FRAME_CURRENT]->key_frame)
>      {
> +        int render_x, render_y;
> +
>          vp56_rac_gets(c, 8);
>          if(vp56_rac_gets(c, 5) > 5)
>              return AVERROR_INVALIDDATA;
> @@ -63,8 +65,11 @@ static int vp5_parse_header(VP56Context *s, const uint8_t *buf, int buf_size)
>                     cols << 4, rows << 4);
>              return AVERROR_INVALIDDATA;
>          }
> -        vp56_rac_gets(c, 8);  /* number of displayed macroblock rows */
> -        vp56_rac_gets(c, 8);  /* number of displayed macroblock cols */
> +        render_y = vp56_rac_gets(c, 8);  /* number of displayed macroblock rows */
> +        render_x = vp56_rac_gets(c, 8);  /* number of displayed macroblock cols */
> +        if (render_x == 0 || render_x > cols ||
> +            render_y == 0 || render_y > rows)
> +            return AVERROR_INVALIDDATA;
>          vp56_rac_gets(c, 2);
>          if (!s->macroblocks || /* first frame */
>              16*cols != s->avctx->coded_width ||

looks good. approve

-- Peter
(A907 E02F A6E5 0CD2 34CD 20D2 6760 79C5 AC40 DD6B)
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