[PATCH] mtd: nand: atmel_nand: fix a possible NULL dereference

[PATCH] mtd: nand: atmel_nand: fix a possible NULL dereference

[LABBE Corentin]

of_match_device could return NULL, and so cause a NULL pointer
dereference later.

Signed-off-by: LABBE Corentin <clabbe.montjoie@gmail.com>
---
 drivers/mtd/nand/atmel_nand.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/mtd/nand/atmel_nand.c b/drivers/mtd/nand/atmel_nand.c
index 475c938..f3cf68b 100644
--- a/drivers/mtd/nand/atmel_nand.c
+++ b/drivers/mtd/nand/atmel_nand.c
@@ -1495,9 +1495,12 @@ static int atmel_of_init_port(struct atmel_nand_host *host,
 	int ecc_mode;
 	struct atmel_nand_data *board = &host->board;
 	enum of_gpio_flags flags = 0;
+	const struct of_device_id *of_id;
 
-	host->caps = (struct atmel_nand_caps *)
-		of_match_device(atmel_nand_dt_ids, host->dev)->data;
+	of_id = of_match_device(atmel_nand_dt_ids, host->dev);
+	if (!of_id)
+		return -ENODEV;
+	host->caps = of_id->data;
 
 	if (of_property_read_u32(np, "atmel,nand-addr-offset", &val) == 0) {
 		if (val >= 32) {
-- 
2.4.10

Re: [PATCH] mtd: nand: atmel_nand: fix a possible NULL dereference

[Joachim Eastwood]

On 12 November 2015 at 08:49, LABBE Corentin <clabbe.montjoie@gmail.com> wrote:
> of_match_device could return NULL, and so cause a NULL pointer
> dereference later.
>
> Signed-off-by: LABBE Corentin <clabbe.montjoie@gmail.com>
> ---
>  drivers/mtd/nand/atmel_nand.c | 7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/mtd/nand/atmel_nand.c b/drivers/mtd/nand/atmel_nand.c
> index 475c938..f3cf68b 100644
> --- a/drivers/mtd/nand/atmel_nand.c
> +++ b/drivers/mtd/nand/atmel_nand.c
> @@ -1495,9 +1495,12 @@ static int atmel_of_init_port(struct atmel_nand_host *host,
>         int ecc_mode;
>         struct atmel_nand_data *board = &host->board;
>         enum of_gpio_flags flags = 0;
> +       const struct of_device_id *of_id;
>
> -       host->caps = (struct atmel_nand_caps *)
> -               of_match_device(atmel_nand_dt_ids, host->dev)->data;
> +       of_id = of_match_device(atmel_nand_dt_ids, host->dev);
> +       if (!of_id)
> +               return -ENODEV;
> +       host->caps = of_id->data;

It might be cleaner to use of_device_get_match_data() here.


regards,
Joachim Eastwood

Re: [PATCH] mtd: nand: atmel_nand: fix a possible NULL dereference

[Joachim Eastwood]

On 12 November 2015 at 08:49, LABBE Corentin <clabbe.montjoie@gmail.com> wrote:
> of_match_device could return NULL, and so cause a NULL pointer
> dereference later.
>
> Signed-off-by: LABBE Corentin <clabbe.montjoie@gmail.com>
> ---
>  drivers/mtd/nand/atmel_nand.c | 7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/mtd/nand/atmel_nand.c b/drivers/mtd/nand/atmel_nand.c
> index 475c938..f3cf68b 100644
> --- a/drivers/mtd/nand/atmel_nand.c
> +++ b/drivers/mtd/nand/atmel_nand.c
> @@ -1495,9 +1495,12 @@ static int atmel_of_init_port(struct atmel_nand_host *host,
>         int ecc_mode;
>         struct atmel_nand_data *board = &host->board;
>         enum of_gpio_flags flags = 0;
> +       const struct of_device_id *of_id;
>
> -       host->caps = (struct atmel_nand_caps *)
> -               of_match_device(atmel_nand_dt_ids, host->dev)->data;
> +       of_id = of_match_device(atmel_nand_dt_ids, host->dev);
> +       if (!of_id)
> +               return -ENODEV;
> +       host->caps = of_id->data;

It might be cleaner to use of_device_get_match_data() here.


regards,
Joachim Eastwood

Re: [PATCH] mtd: nand: atmel_nand: fix a possible NULL dereference

[kbuild test robot]

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Hi LABBE,

[auto build test WARNING on mtd/master]
[also build test WARNING on v4.3 next-20151112]

url:    https://github.com/0day-ci/linux/commits/LABBE-Corentin/mtd-nand-atmel_nand-fix-a-possible-NULL-dereference/20151112-155258
base:   git://git.infradead.org/linux-mtd.git master
config: arm-at91_dt_defconfig (attached as .config)
reproduce:
        wget https://git.kernel.org/cgit/linux/kernel/git/wfg/lkp-tests.git/plain/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        make.cross ARCH=arm 

All warnings (new ones prefixed by >>):

   drivers/mtd/nand/atmel_nand.c: In function 'atmel_of_init_port':
>> drivers/mtd/nand/atmel_nand.c:1503:13: warning: assignment discards 'const' qualifier from pointer target type
     host->caps = of_id->data;
                ^

vim +/const +1503 drivers/mtd/nand/atmel_nand.c

  1487	
  1488	static const struct of_device_id atmel_nand_dt_ids[];
  1489	
  1490	static int atmel_of_init_port(struct atmel_nand_host *host,
  1491				      struct device_node *np)
  1492	{
  1493		u32 val;
  1494		u32 offset[2];
  1495		int ecc_mode;
  1496		struct atmel_nand_data *board = &host->board;
  1497		enum of_gpio_flags flags = 0;
  1498		const struct of_device_id *of_id;
  1499	
  1500		of_id = of_match_device(atmel_nand_dt_ids, host->dev);
  1501		if (!of_id)
  1502			return -ENODEV;
> 1503		host->caps = of_id->data;
  1504	
  1505		if (of_property_read_u32(np, "atmel,nand-addr-offset", &val) == 0) {
  1506			if (val >= 32) {
  1507				dev_err(host->dev, "invalid addr-offset %u\n", val);
  1508				return -EINVAL;
  1509			}
  1510			board->ale = val;
  1511		}

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

[-- Attachment #2: .config.gz --]
[-- Type: application/octet-stream, Size: 20006 bytes --]

Re: [PATCH] mtd: nand: atmel_nand: fix a possible NULL dereference

[LABBE Corentin]

On Thu, Nov 12, 2015 at 09:29:57AM +0100, Joachim Eastwood wrote:
> On 12 November 2015 at 08:49, LABBE Corentin <clabbe.montjoie@gmail.com> wrote:
> > of_match_device could return NULL, and so cause a NULL pointer
> > dereference later.
> >
> > Signed-off-by: LABBE Corentin <clabbe.montjoie@gmail.com>
> > ---
> >  drivers/mtd/nand/atmel_nand.c | 7 +++++--
> >  1 file changed, 5 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/mtd/nand/atmel_nand.c b/drivers/mtd/nand/atmel_nand.c
> > index 475c938..f3cf68b 100644
> > --- a/drivers/mtd/nand/atmel_nand.c
> > +++ b/drivers/mtd/nand/atmel_nand.c
> > @@ -1495,9 +1495,12 @@ static int atmel_of_init_port(struct atmel_nand_host *host,
> >         int ecc_mode;
> >         struct atmel_nand_data *board = &host->board;
> >         enum of_gpio_flags flags = 0;
> > +       const struct of_device_id *of_id;
> >
> > -       host->caps = (struct atmel_nand_caps *)
> > -               of_match_device(atmel_nand_dt_ids, host->dev)->data;
> > +       of_id = of_match_device(atmel_nand_dt_ids, host->dev);
> > +       if (!of_id)
> > +               return -ENODEV;
> > +       host->caps = of_id->data;
> 
> It might be cleaner to use of_device_get_match_data() here.
> 

I agree, I will resend shortly with it.
And this time, I wont forgot the patch which permit to supress the kbuild_robot warning.

Regards

LABBE Corentin