[FFmpeg-devel] [PATCH] avcodec/cinepakenc: Fix invalid shifts

[Paul B Mahol]

Still ok.

On 10/6/19, Andreas Rheinhardt <andreas.rheinhardt at gmail.com> wrote:
> Fixes: left shift of 1 by 31 places cannot be represented in type 'int'.
> Affected the FATE-tests vsynth1-cinepak, vsynth2-cinepak and
> vsynth_lena-cinepak. Also fixes ticket #8220.
>
> Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt at gmail.com>
> ---
> I am resending this, because in the meantime ticket #8220 has been
> opened about this, so that the commit message needs to be updated.
>
>  libavcodec/cinepakenc.c | 11 ++++++-----
>  1 file changed, 6 insertions(+), 5 deletions(-)
>
> diff --git a/libavcodec/cinepakenc.c b/libavcodec/cinepakenc.c
> index 93917fafe8..6024df0fba 100644
> --- a/libavcodec/cinepakenc.c
> +++ b/libavcodec/cinepakenc.c
> @@ -544,8 +544,9 @@ static int encode_mode(CinepakEncContext *s, int h,
>                         uint8_t *last_data[4], int last_linesize[4],
>                         strip_info *info, unsigned char *buf)
>  {
> -    int x, y, z, flags, bits, temp_size, header_ofs, ret = 0, mb_count =
> s->w * h / MB_AREA;
> +    int x, y, z, bits, temp_size, header_ofs, ret = 0, mb_count = s->w * h
> / MB_AREA;
>      int needs_extra_bit, should_write_temp;
> +    uint32_t flags;
>      unsigned char temp[64]; // 32/2 = 16 V4 blocks at 4 B each -> 64 B
>      mb_info *mb;
>      uint8_t *sub_scratch_data[4] = { 0 }, *sub_last_data[4] = { 0 };
> @@ -599,7 +600,7 @@ static int encode_mode(CinepakEncContext *s, int h,
>              flags = 0;
>              for (y = x; y < FFMIN(x + 32, mb_count); y++)
>                  if (s->mb[y].best_encoding == ENC_V4)
> -                    flags |= 1 << (31 - y + x);
> +                    flags |= 1U << (31 - y + x);
>
>              AV_WB32(&buf[ret], flags);
>              ret += 4;
> @@ -626,13 +627,13 @@ static int encode_mode(CinepakEncContext *s, int h,
>
>          for (x = 0; x < mb_count; x++) {
>              mb                = &s->mb[x];
> -            flags            |= (mb->best_encoding != ENC_SKIP) << (31 -
> bits++);
> +            flags            |= (uint32_t)(mb->best_encoding != ENC_SKIP)
> << (31 - bits++);
>              needs_extra_bit   = 0;
>              should_write_temp = 0;
>
>              if (mb->best_encoding != ENC_SKIP) {
>                  if (bits < 32)
> -                    flags |= (mb->best_encoding == ENC_V4) << (31 -
> bits++);
> +                    flags |= (uint32_t)(mb->best_encoding == ENC_V4) << (31
> - bits++);
>                  else
>                      needs_extra_bit = 1;
>              }
> @@ -651,7 +652,7 @@ static int encode_mode(CinepakEncContext *s, int h,
>              }
>
>              if (needs_extra_bit) {
> -                flags = (mb->best_encoding == ENC_V4) << 31;
> +                flags = (uint32_t)(mb->best_encoding == ENC_V4) << 31;
>                  bits  = 1;
>              }
>
> --
> 2.20.1
>
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