Re: [FFmpeg-devel] [PATCH 2/3] mlvdec: validate bits_per_coded_sample

[Peter Ross]

On Sat, Dec 19, 2015 at 11:49:02PM +0100, Andreas Cadhalpun wrote:
> A negative bits_per_coded_sample doesn't make sense.
> If it is too large, the size calculation for av_get_packet overflows,
> resulting in allocation of a too small buffer.
> 
> Signed-off-by: Andreas Cadhalpun <andreas.cadhal...@googlemail.com>
> ---
>  libavformat/mlvdec.c | 9 +++++++++
>  1 file changed, 9 insertions(+)
> 
> diff --git a/libavformat/mlvdec.c b/libavformat/mlvdec.c
> index 4b3bdc1..2e57aae 100644
> --- a/libavformat/mlvdec.c
> +++ b/libavformat/mlvdec.c
> @@ -135,6 +135,15 @@ static int scan_file(AVFormatContext *avctx, AVStream 
> *vst, AVStream *ast, int f
>                  avpriv_request_sample(avctx, "raw api version");
>              avio_skip(pb, 20); // pointer, width, height, pitch, frame_size
>              vst->codec->bits_per_coded_sample = avio_rl32(pb);
> +            if (vst->codec->bits_per_coded_sample < 0 ||
> +                (vst->codec->width && vst->codec->height &&
> +                vst->codec->bits_per_coded_sample > (INT_MAX - 7) / 
> (vst->codec->width * vst->codec->height))) {
> +                av_log(avctx, AV_LOG_ERROR,
> +                       "invalid bits_per_coded_sample %d (size: %dx%d)\n",
> +                       vst->codec->bits_per_coded_sample,
> +                       vst->codec->width, vst->codec->height);
> +                return AVERROR_INVALIDDATA;
> +            }
>              avio_skip(pb, 8 + 16 + 24); // black_level, white_level, xywh, 
> active_area, exposure_bias
>              if (avio_rl32(pb) != 0x2010100) /* RGGB */
>                  avpriv_request_sample(avctx, "cfa_pattern");
> -- 
> 2.6.2

Looks good.

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

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