[PATCH] ALSA: hwdep: fix a left shifting 1 by 31 UB bug

[Takashi Iwai]

On Tue, 26 May 2020 02:39:21 +0200,
Changming Liu wrote:
> 
> The "info.index" variable can be 31 in "1 << info.index".
> This might trigger an undefined behavior since 1 is signed.
> 
> Fix this by casting 1 to 1u just to be sure "1u << 31" is defined.
> 
> Signed-off-by: Changming Liu <liu.changm at northeastern.edu>

Thanks for the patch.

Unfortunately it seems that your MUA modified in quoted-printable and
inapplicable with git-am as is.  Since the changes are so small, I
manually applied it now.

Please fix the setup of your MUA at the next time, or better to try
git-send-email to submit directly.


thanks,

Takashi

> ---
>  sound/core/hwdep.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/sound/core/hwdep.c b/sound/core/hwdep.c
> index b412d3b3d5ff..21edb8ac95eb 100644
> --- a/sound/core/hwdep.c
> +++ b/sound/core/hwdep.c
> @@ -216,12 +216,12 @@ static int snd_hwdep_dsp_load(struct snd_hwdep *hw,
>         if (info.index >= 32)
>                 return -EINVAL;
>         /* check whether the dsp was already loaded */
> -       if (hw->dsp_loaded & (1 << info.index))
> +       if (hw->dsp_loaded & (1u << info.index))
>                 return -EBUSY;
>         err = hw->ops.dsp_load(hw, &info);
>         if (err < 0)
>                 return err;
> -       hw->dsp_loaded |= (1 << info.index);
> +       hw->dsp_loaded |= (1u << info.index);
>         return 0;
>  }
> 
> --
> 2.17.1
>