[PATCH] mtd: rawnand: atmel: Fix potential NULL pointer dereference

[PATCH] mtd: rawnand: atmel: Fix potential NULL pointer dereference

[Gustavo A. R. Silva]

There is a potential execution path in which function
of_find_compatible_node() returns NULL. In such a case,
we end up having a NULL pointer dereference when accessing
pointer *nfc_np* in function of_clk_get().

So, we better don't take any chances and fix this by null
checking pointer *nfc_np* before calling of_clk_get().

Addresses-Coverity-ID: 1473052 ("Dereference null return value")
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
---
 drivers/mtd/nand/raw/atmel/nand-controller.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/mtd/nand/raw/atmel/nand-controller.c b/drivers/mtd/nand/raw/atmel/nand-controller.c
index a38633a..ffa0c6b6 100644
--- a/drivers/mtd/nand/raw/atmel/nand-controller.c
+++ b/drivers/mtd/nand/raw/atmel/nand-controller.c
@@ -2035,6 +2035,11 @@ atmel_hsmc_nand_controller_legacy_init(struct atmel_hsmc_nand_controller *nc)
 	nfc_np = of_find_compatible_node(dev->of_node, NULL,
 					 "atmel,sama5d3-nfc");
 
+	if (!nfc_np) {
+		dev_err(dev, "Could not find device node for sama5d3-nfc\n");
+		return -ENODEV;
+	}
+
 	nc->clk = of_clk_get(nfc_np, 0);
 	if (IS_ERR(nc->clk)) {
 		ret = PTR_ERR(nc->clk);
-- 
2.7.4

[PATCH] mtd: rawnand: atmel: Fix potential NULL pointer dereference

[Boris Brezillon]

Hi Gustavo,

On Tue, 18 Sep 2018 08:33:17 -0500
"Gustavo A. R. Silva" <gustavo@embeddedor.com> wrote:

> There is a potential execution path in which function
> of_find_compatible_node() returns NULL. In such a case,
> we end up having a NULL pointer dereference when accessing
> pointer *nfc_np* in function of_clk_get().
> 
> So, we better don't take any chances and fix this by null
> checking pointer *nfc_np* before calling of_clk_get().
> 
> Addresses-Coverity-ID: 1473052 ("Dereference null return value")

Can you add a Fixes tag here?

> Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
> ---
>  drivers/mtd/nand/raw/atmel/nand-controller.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/drivers/mtd/nand/raw/atmel/nand-controller.c b/drivers/mtd/nand/raw/atmel/nand-controller.c
> index a38633a..ffa0c6b6 100644
> --- a/drivers/mtd/nand/raw/atmel/nand-controller.c
> +++ b/drivers/mtd/nand/raw/atmel/nand-controller.c
> @@ -2035,6 +2035,11 @@ atmel_hsmc_nand_controller_legacy_init(struct atmel_hsmc_nand_controller *nc)
>  	nfc_np = of_find_compatible_node(dev->of_node, NULL,
>  					 "atmel,sama5d3-nfc");
>  

Can you drop this blank line?

> +	if (!nfc_np) {
> +		dev_err(dev, "Could not find device node for sama5d3-nfc\n");
> +		return -ENODEV;
> +	}
> +
>  	nc->clk = of_clk_get(nfc_np, 0);
>  	if (IS_ERR(nc->clk)) {
>  		ret = PTR_ERR(nc->clk);

Thanks,

Boris

[PATCH] mtd: rawnand: atmel: Fix potential NULL pointer dereference

[Gustavo A. R. Silva]

Hi Boris,

On 9/18/18 8:40 AM, Boris Brezillon wrote:
> Hi Gustavo,
> 
> On Tue, 18 Sep 2018 08:33:17 -0500
> "Gustavo A. R. Silva" <gustavo@embeddedor.com> wrote:
> 
>> There is a potential execution path in which function
>> of_find_compatible_node() returns NULL. In such a case,
>> we end up having a NULL pointer dereference when accessing
>> pointer *nfc_np* in function of_clk_get().
>>
>> So, we better don't take any chances and fix this by null
>> checking pointer *nfc_np* before calling of_clk_get().
>>
>> Addresses-Coverity-ID: 1473052 ("Dereference null return value")
> 
> Can you add a Fixes tag here?
> 

Yep.

>> Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
>> ---
>>  drivers/mtd/nand/raw/atmel/nand-controller.c | 5 +++++
>>  1 file changed, 5 insertions(+)
>>
>> diff --git a/drivers/mtd/nand/raw/atmel/nand-controller.c b/drivers/mtd/nand/raw/atmel/nand-controller.c
>> index a38633a..ffa0c6b6 100644
>> --- a/drivers/mtd/nand/raw/atmel/nand-controller.c
>> +++ b/drivers/mtd/nand/raw/atmel/nand-controller.c
>> @@ -2035,6 +2035,11 @@ atmel_hsmc_nand_controller_legacy_init(struct atmel_hsmc_nand_controller *nc)
>>  	nfc_np = of_find_compatible_node(dev->of_node, NULL,
>>  					 "atmel,sama5d3-nfc");
>>  
> 
> Can you drop this blank line?
> 

OK. Sure thing.

I'll send v2 shortly.

Thanks for the feedback.
--
Gustavo