[alsa-devel] [PATCH] sound/oss/opl3: validate voice and channel indexes

[Takashi Iwai]

At Wed, 23 Mar 2011 11:42:57 -0400,
Dan Rosenberg wrote:
> 
> User-controllable indexes for voice and channel values may cause reading
> and writing beyond the bounds of their respective arrays, leading to
> potentially exploitable memory corruption.  Validate these indexes.
> 
> Signed-off-by: Dan Rosenberg <drosenberg at vsecurity.com>
> Cc: stable at kernel.org

Applied now.  Thanks.


Takashi


> ---
>  sound/oss/opl3.c |   15 +++++++++++++--
>  1 files changed, 13 insertions(+), 2 deletions(-)
> 
> diff --git a/sound/oss/opl3.c b/sound/oss/opl3.c
> index 938c48c..e9d443e 100644
> --- a/sound/oss/opl3.c
> +++ b/sound/oss/opl3.c
> @@ -849,6 +849,10 @@ static int opl3_load_patch(int dev, int format, const char __user *addr,
>  
>  static void opl3_panning(int dev, int voice, int value)
>  {
> +
> +	if (voice < 0 || voice >= devc->nr_voice)
> +		return;
> +
>  	devc->voc[voice].panning = value;
>  }
>  
> @@ -1066,8 +1070,15 @@ static int opl3_alloc_voice(int dev, int chn, int note, struct voice_alloc_info
>  
>  static void opl3_setup_voice(int dev, int voice, int chn)
>  {
> -	struct channel_info *info =
> -	&synth_devs[dev]->chn_info[chn];
> +	struct channel_info *info;
> +
> +	if (voice < 0 || voice >= devc->nr_voice)
> +		return;
> +
> +	if (chn < 0 || chn > 15)
> +		return;
> +
> +	info = &synth_devs[dev]->chn_info[chn];
>  
>  	opl3_set_instr(dev, voice, info->pgm_num);
>  
> 
> 
>