[vlc-devel] [PATCH] amem: fix integer overflow above 262143Hz

[Farid HAMMANE]

Hello,

If this patch is ok for you, could you please apply it? I have another
patch waiting that depends on it (support of multiple formats).

Thank you in advance

Best regards

Farid



On Wed, Jan 8, 2020 at 9:23 PM Farid Hammane <farid.hammane at gmail.com>
wrote:

> The variable 'rate' in aout_sys_t had 18bits, which was
> not enough to represent values greater than 262143.
>
> This patch increases the number of bits reserved for
> the sample rate while keeping enough bits for 'channels'
> to be able to represent up to 1023;
>
> This patch also fixes an inconsistency in the number
> of supported channels. According to source code, where
> channel mapping is configured, amem only supports 8
> channels.
>
> Signed-off-by: Farid Hammane <farid.hammane at gmail.com>
> ---
>  modules/audio_output/amem.c | 9 +++++----
>  1 file changed, 5 insertions(+), 4 deletions(-)
>
> diff --git a/modules/audio_output/amem.c b/modules/audio_output/amem.c
> index 0e10a86211..f89b5ec4fe 100644
> --- a/modules/audio_output/amem.c
> +++ b/modules/audio_output/amem.c
> @@ -31,6 +31,7 @@ static int Open (vlc_object_t *);
>  static void Close (vlc_object_t *);
>
>  #define AMEM_SAMPLE_RATE_MAX 384000
> +#define AMEM_CHAN_MAX 8
>
>  vlc_module_begin ()
>      set_shortname (N_("Audio memory"))
> @@ -49,7 +50,7 @@ vlc_module_begin ()
>          change_private()
>      add_integer ("amem-channels", 2,
>                   N_("Channels count"), N_("Channels count"), false)
> -        change_integer_range (1, AOUT_CHAN_MAX)
> +        change_integer_range (1, AMEM_CHAN_MAX)
>          change_private()
>
>  vlc_module_end ()
> @@ -67,8 +68,8 @@ typedef struct
>          };
>          struct
>          {
> -             unsigned rate:18;
> -             unsigned channels:14;
> +             unsigned rate:22;
> +             unsigned channels:10;
>          };
>      };
>      void (*play) (void *opaque, const void *data, unsigned count, int64_t
> pts);
> @@ -229,7 +230,7 @@ static int Start (audio_output_t *aout,
> audio_sample_format_t *fmt)
>
>      /* Ensure that format is supported */
>      if (fmt->i_rate == 0 || fmt->i_rate > AMEM_SAMPLE_RATE_MAX
> -     || channels == 0 || channels > AOUT_CHAN_MAX
> +     || channels == 0 || channels > AMEM_CHAN_MAX
>       || strcmp(format, "S16N") /* TODO: amem-format */)
>      {
>          msg_Err (aout, "format not supported: %s, %u channel(s), %u Hz",
> --
> 2.20.1
>
>
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