[alsa-devel] [PATCH] ASoC: rsnd: Fix possible NULL pointer dereference

[Kuninori Morimoto]

Hi Marek

> In case the "clock-frequency" DT property is not present, the
> of_find_property(np, "clock-frequency", NULL) will return NULL
> and the subsequent req_size = prop->length / sizeof(u32); will
> trigger a NULL pointer dereference.
> 
> This patch adds check for the NULL return value and propagates
> the error into the caller of the function.
> 
> Signed-off-by: Marek Vasut <marek.vasut+renesas at gmail.com>
> Cc: Geert Uytterhoeven <geert+renesas at glider.be>
> Cc: Hiroyuki Yokoyama <hiroyuki.yokoyama.vx at renesas.com>
> Cc: Kuninori Morimoto <kuninori.morimoto.gx at renesas.com>
> Cc: Mark Brown <broonie at kernel.org>
> Cc: linux-renesas-soc at vger.kernel.org
> ---

Thank you for your patch, it was my fail.
But your patch will breaks Lager board sound
(= it doesn't need clkout, and have no "clock-frequency")

I will try to fix this issue

>  sound/soc/sh/rcar/adg.c | 13 +++++++++----
>  1 file changed, 9 insertions(+), 4 deletions(-)
> 
> diff --git a/sound/soc/sh/rcar/adg.c b/sound/soc/sh/rcar/adg.c
> index 96fef91b480c..a7cbe7e89dfc 100644
> --- a/sound/soc/sh/rcar/adg.c
> +++ b/sound/soc/sh/rcar/adg.c
> @@ -425,8 +425,7 @@ static void rsnd_adg_get_clkin(struct rsnd_priv *priv,
>  		dev_dbg(dev, "clk %d : %p : %ld\n", i, clk, clk_get_rate(clk));
>  }
>  
> -static void rsnd_adg_get_clkout(struct rsnd_priv *priv,
> -				struct rsnd_adg *adg)
> +static int rsnd_adg_get_clkout(struct rsnd_priv *priv, struct rsnd_adg *adg)
>  {
>  	struct clk *clk;
>  	struct device *dev = rsnd_priv_to_dev(priv);
> @@ -459,7 +458,10 @@ static void rsnd_adg_get_clkout(struct rsnd_priv *priv,
>  	 * ADG supports BRRA/BRRB output only
>  	 * this means all clkout0/1/2/3 will be same rate
>  	 */
> -	prop = of_find_property(np, "clock-frequency", NULL);;
> +	prop = of_find_property(np, "clock-frequency", NULL);
> +	if (!prop)
> +		return -EINVAL;
> +
>  	req_size = prop->length / sizeof(u32);
>  
>  	of_property_read_u32_array(np, "clock-frequency", req_rate, req_size);
> @@ -568,6 +570,7 @@ static void rsnd_adg_get_clkout(struct rsnd_priv *priv,
>  		dev_dbg(dev, "clkout %d : %p : %ld\n", i, clk, clk_get_rate(clk));
>  	dev_dbg(dev, "BRGCKR = 0x%08x, BRRA/BRRB = 0x%x/0x%x\n",
>  		ckr, rbga, rbgb);
> +	return 0;
>  }
>  
>  int rsnd_adg_probe(struct rsnd_priv *priv)
> @@ -589,7 +592,9 @@ int rsnd_adg_probe(struct rsnd_priv *priv)
>  		return ret;
>  
>  	rsnd_adg_get_clkin(priv, adg);
> -	rsnd_adg_get_clkout(priv, adg);
> +	ret = rsnd_adg_get_clkout(priv, adg);
> +	if (ret)
> +		return ret;
>  
>  	if (of_get_property(np, "clkout-lr-asynchronous", NULL))
>  		adg->flags = LRCLK_ASYNC;
> -- 
> 2.11.0
>