2018-09-18 13:34:41

by Gustavo A. R. Silva

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

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 <[email protected]>
---
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



2018-09-18 13:41:15

by Boris Brezillon

[permalink] [raw]
Subject: Re: [PATCH] mtd: rawnand: atmel: Fix potential NULL pointer dereference

Hi Gustavo,

On Tue, 18 Sep 2018 08:33:17 -0500
"Gustavo A. R. Silva" <[email protected]> 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 <[email protected]>
> ---
> 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

2018-09-18 13:45:49

by Gustavo A. R. Silva

[permalink] [raw]
Subject: Re: [PATCH] mtd: rawnand: atmel: Fix potential NULL pointer dereference

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" <[email protected]> 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 <[email protected]>
>> ---
>> 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