From: Dan Carpenter <dan.carpenter@oracle.com>
To: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Cc: support.opensource@diasemi.com, lgirdwood@gmail.com,
broonie@kernel.org, perex@perex.cz, tiwai@suse.com,
Adam.Thomson.Opensource@diasemi.com, alsa-devel@alsa-project.org,
linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org
Subject: Re: [PATCH] ASoC: da7219: Fix an out-of-bound read in an error handling path
Date: Wed, 23 Jun 2021 12:46:55 +0300 [thread overview]
Message-ID: <20210623094655.GB2116@kadam> (raw)
In-Reply-To: <4fdde55198294a07f04933f7cef937fcb654c901.1624425670.git.christophe.jaillet@wanadoo.fr>
On Wed, Jun 23, 2021 at 07:22:45AM +0200, Christophe JAILLET wrote:
> If 'of_clk_add_hw_provider()' fails, the previous 'for' loop will have
> run completely and 'i' is know to be 'DA7219_DAI_NUM_CLKS'.
>
> In such a case, there will be an out-of-bounds access when using
> 'da7219->dai_clks_lookup[i]' and '&da7219->dai_clks_hw[i]'.
>
> To avoid that, add a new label, 'err_free_all', which set the expected
> value of 'i' in such a case.
>
> Fixes: 78013a1cf297 ("ASoC: da7219: Fix clock handling around codec level probe")
> Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
> ---
> sound/soc/codecs/da7219.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/sound/soc/codecs/da7219.c b/sound/soc/codecs/da7219.c
> index 13009d08b09a..1e8b491d1fd3 100644
> --- a/sound/soc/codecs/da7219.c
> +++ b/sound/soc/codecs/da7219.c
> @@ -2204,12 +2204,14 @@ static int da7219_register_dai_clks(struct snd_soc_component *component)
> da7219->clk_hw_data);
> if (ret) {
> dev_err(dev, "Failed to register clock provider\n");
> - goto err;
> + goto err_free_all;
> }
> }
>
> return 0;
>
> +err_free_all:
> + i = DA7219_DAI_NUM_CLKS - 1;
> err:
> do {
> if (da7219->dai_clks_lookup[i])
This do while statement is wrong and it leads to potentially calling
clk_hw_unregister() on clks that haven't been registered.
I think that calling clk_hw_unregister() on unregistered clocks is
supposed to okay but I found a case where it leads to a WARN_ON()
(Nothing else harmful). It's in __clk_register() if the alloc_clk()
fails:
hw->clk = alloc_clk(core, NULL, NULL);
if (IS_ERR(hw->clk)) {
ret = PTR_ERR(hw->clk);
goto fail_create_clk; // <- forgot to set hw->clk = NULL
}
The better way to handle errors from loops is to clean up partial
iterations before doing the goto. So add a clk_hw_unregister() if the
dai_clk_lookup = clkdev_hw_create() assignment fails. Then use a
while (--i >= 0) loop in the unwind section:
err_free_all:
i = DA7219_DAI_NUM_CLKS;
err:
while (--i >= 0) {
regards,
dan carpenter
next prev parent reply other threads:[~2021-06-23 9:48 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-23 5:22 [PATCH] ASoC: da7219: Fix an out-of-bound read in an error handling path Christophe JAILLET
2021-06-23 9:46 ` Dan Carpenter [this message]
2021-06-23 21:09 ` Christophe JAILLET
2021-06-23 21:13 ` Christophe JAILLET
2021-06-23 21:13 ` Christophe JAILLET
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