[FFmpeg-devel] [PATCH] wavpack: limit extra_bits to 32 and use get_bits_long

[Paul B Mahol]

On 7/2/15, Andreas Cadhalpun <andreas.cadhalpun at googlemail.com> wrote:
> More than 32 bits can't be stored in an integer and get_bits should not
> be used with more than 25 bits.
>
> Signed-off-by: Andreas Cadhalpun <Andreas.Cadhalpun at googlemail.com>
> ---
>  libavcodec/wavpack.c | 8 ++++++--
>  1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/libavcodec/wavpack.c b/libavcodec/wavpack.c
> index d91b66c..554367b 100644
> --- a/libavcodec/wavpack.c
> +++ b/libavcodec/wavpack.c
> @@ -271,7 +271,7 @@ static inline int
> wv_get_value_integer(WavpackFrameContext *s, uint32_t *crc,
>
>          if (s->got_extra_bits &&
>              get_bits_left(&s->gb_extra_bits) >= s->extra_bits) {
> -            S   |= get_bits(&s->gb_extra_bits, s->extra_bits);
> +            S   |= get_bits_long(&s->gb_extra_bits, s->extra_bits);
>              *crc = *crc * 9 + (S & 0xffff) * 3 + ((unsigned)S >> 16);
>          }
>      }
> @@ -835,7 +835,11 @@ static int wavpack_decode_block(AVCodecContext *avctx,
> int block_no,
>                  continue;
>              }
>              bytestream2_get_buffer(&gb, val, 4);
> -            if (val[0]) {
> +            if (val[0] > 32) {
> +                av_log(avctx, AV_LOG_ERROR,
> +                       "Invalid INT32INFO, extra_bits = %d (> 32)\n",
> val[0]);
> +                continue;
> +            } else if (val[0]) {
>                  s->extra_bits = val[0];
>              } else if (val[1]) {
>                  s->shift = val[1];
> --
> 2.1.4
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>

lgtm