From: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
To: Ben Dooks <ben-linux@fluff.org>,
Jaehoon Chung <jh80.chung@samsung.com>,
Adrian Hunter <adrian.hunter@intel.com>,
Ulf Hansson <ulf.hansson@linaro.org>,
linux-mmc@vger.kernel.org, linux-kernel@vger.kernel.org
Cc: Marek Szyprowski <m.szyprowski@samsung.com>,
Sylwester Nawrocki <snawrocki@kernel.org>
Subject: Re: [PATCH 1/3] mmc: sdhci-s3c: fix possible NULL pointer dereference when probed via platform
Date: Wed, 14 Apr 2021 17:25:25 +0200 [thread overview]
Message-ID: <a0ac5d21-acc1-825a-1585-f8d897902b14@canonical.com> (raw)
In-Reply-To: <20210414151242.102313-1-krzysztof.kozlowski@canonical.com>
On 14/04/2021 17:12, Krzysztof Kozlowski wrote:
> The driver can be matched by legacy platform way or OF-device matching.
> In the first case, of_match_node() can return NULL, which immediately
> would be dereferenced to get the match data.
>
> Addresses-Coverity: Dereference null return value
> Fixes: cd1b00eb24b0 ("mmc: sdhci-s3c: Add device tree support")
> Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
> ---
>
> Not tested on HW, but the code should be equivalent (plus safer).
>
> drivers/mmc/host/sdhci-s3c.c | 12 +++---------
> 1 file changed, 3 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/mmc/host/sdhci-s3c.c b/drivers/mmc/host/sdhci-s3c.c
> index f48a788a9d3d..8e1dca625620 100644
> --- a/drivers/mmc/host/sdhci-s3c.c
> +++ b/drivers/mmc/host/sdhci-s3c.c
> @@ -20,6 +20,7 @@
> #include <linux/gpio.h>
> #include <linux/module.h>
> #include <linux/of.h>
> +#include <linux/of_device.h>
> #include <linux/of_gpio.h>
> #include <linux/pm.h>
> #include <linux/pm_runtime.h>
> @@ -461,19 +462,12 @@ static int sdhci_s3c_parse_dt(struct device *dev,
> }
> #endif
>
> -#ifdef CONFIG_OF
> -static const struct of_device_id sdhci_s3c_dt_match[];
> -#endif
> -
> static inline struct sdhci_s3c_drv_data *sdhci_s3c_get_driver_data(
> struct platform_device *pdev)
> {
> #ifdef CONFIG_OF
> - if (pdev->dev.of_node) {
> - const struct of_device_id *match;
> - match = of_match_node(sdhci_s3c_dt_match, pdev->dev.of_node);
Now I have second thoughts whether NULL pointer can actually happen. If
device is matched via platform/board files, maybe the pdev->dev.of_node
will be NULL thus skipping this branch?
Could there be a case where device is matched via platform_device_id()
(which has different name than compatible!) and (pdev->dev.of_node) is
still assigned? Maybe in case of out of tree DTS?
Anyway, the patch makes the code simpler/smaller, so I still think it is
reasonable. Just the severity of issue is questionable...
Best regards,
Krzysztof
next prev parent reply other threads:[~2021-04-14 15:25 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-14 15:12 [PATCH 1/3] mmc: sdhci-s3c: fix possible NULL pointer dereference when probed via platform Krzysztof Kozlowski
2021-04-14 15:12 ` [PATCH 2/3] mmc: sdhci-s3c: correct kerneldoc of sdhci_s3c_drv_data Krzysztof Kozlowski
2021-04-14 15:12 ` [PATCH 3/3] mmc: sdhci-s3c: constify uses of driver/match data Krzysztof Kozlowski
2021-04-14 15:25 ` Krzysztof Kozlowski [this message]
2021-04-14 16:49 ` [PATCH 1/3] mmc: sdhci-s3c: fix possible NULL pointer dereference when probed via platform Sylwester Nawrocki
2021-04-15 8:41 ` Krzysztof Kozlowski
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