[FFmpeg-devel] [FFmpeg-cvslog] avcodec/alsdec: Fix reading 0 mantisse bits

[James Almer]

> ffmpeg | branch: master | Michael Niedermayer <michael at niedermayer.cc> | Thu Sep  8 22:02:44 2016 +0200| [037422178d7f1d0dd09e1ce424dd61a69e77668b] | committer: Michael Niedermayer
>
> avcodec/alsdec: Fix reading 0 mantisse bits
>
> Fixes assertion failure
> Fixes: 848c24abc1721c9e3d1ba7bfee8d9fcc/asan_heap-oob_1d99eca_3709_567bba70d67e7d62714dcf56f26fb1da.mp4
>
> Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
> Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
>
> > http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=037422178d7f1d0dd09e1ce424dd61a69e77668b
> ---
>
>  libavcodec/alsdec.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/libavcodec/alsdec.c b/libavcodec/alsdec.c
> index 1bb71f5..8c4ff53 100644
> --- a/libavcodec/alsdec.c
> +++ b/libavcodec/alsdec.c
> @@ -1527,7 +1527,7 @@ static int read_diff_float_data(ALSDecContext *ctx, unsigned int ra_frame) {
>              if (!get_bits1(gb)) { //uncompressed
>                  for (i = 0; i < frame_length; ++i) {
>                      if (ctx->raw_samples[c][i] != 0) {
> -                        raw_mantissa[c][i] = get_bits(gb, nbits[i]);
> +                        raw_mantissa[c][i] = nbits[i] ? get_bits(gb, nbits[i]) : 0;

No point changing it now, but keep in mind for future reference that there's a get_bitsz()
function. It in fact expands to this same code you wrote.

>                      }
>                  }
>              } else { //compressed
>