2016-12-22 11:45:48

by Arvind Yadav

Subject: [v1] i2c: busses: i2c-designware-pcidrv:- Handle return NULL error from pcim_iomap_table

Here, If pcim_iomap_table will fail. It will return NULL.
Kernel can run into a NULL-pointer dereference.
This error check will avoid NULL pointer dereference.

Signed-off-by: Arvind Yadav <[email protected]>
---
drivers/i2c/busses/i2c-designware-pcidrv.c | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/drivers/i2c/busses/i2c-designware-pcidrv.c b/drivers/i2c/busses/i2c-designware-pcidrv.c
index d6423cf..6a1907d 100644
--- a/drivers/i2c/busses/i2c-designware-pcidrv.c
+++ b/drivers/i2c/busses/i2c-designware-pcidrv.c
@@ -235,6 +235,10 @@ static int i2c_dw_pci_probe(struct pci_dev *pdev,
dev->controller = controller;
dev->get_clk_rate_khz = i2c_dw_get_clk_rate_khz;
dev->base = pcim_iomap_table(pdev)[0];
+ if (!dev->base) {
+ dev_err(&pdev->dev, "I/O map table allocation failed\n");
+ return -ENOMEM;
+ }
dev->dev = &pdev->dev;
dev->irq = pdev->irq;

--
1.7.9.5

2016-12-22 11:51:05

by Mika Westerberg

Subject: Re: [v1] i2c: busses: i2c-designware-pcidrv:- Handle return NULL error from pcim_iomap_table

On Thu, Dec 22, 2016 at 05:09:19PM +0530, Arvind Yadav wrote:
> Here, If pcim_iomap_table will fail. It will return NULL.
> Kernel can run into a NULL-pointer dereference.
> This error check will avoid NULL pointer dereference.
>
> Signed-off-by: Arvind Yadav <[email protected]>
> ---
> drivers/i2c/busses/i2c-designware-pcidrv.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/drivers/i2c/busses/i2c-designware-pcidrv.c b/drivers/i2c/busses/i2c-designware-pcidrv.c
> index d6423cf..6a1907d 100644
> --- a/drivers/i2c/busses/i2c-designware-pcidrv.c
> +++ b/drivers/i2c/busses/i2c-designware-pcidrv.c
> @@ -235,6 +235,10 @@ static int i2c_dw_pci_probe(struct pci_dev *pdev,
> dev->controller = controller;
> dev->get_clk_rate_khz = i2c_dw_get_clk_rate_khz;
> dev->base = pcim_iomap_table(pdev)[0];
> + if (!dev->base) {
> + dev_err(&pdev->dev, "I/O map table allocation failed\n");
> + return -ENOMEM;

Are you sure this can actually happen?

IIRC pcim_iomap_regions() (which is called before this) makes sure the
BARs you access here are valid.

2016-12-22 14:35:15

by Andy Shevchenko

Subject: Re: [v1] i2c: busses: i2c-designware-pcidrv:- Handle return NULL error from pcim_iomap_table

On Thu, 2016-12-22 at 17:09 +0530, Arvind Yadav wrote:
> Here, If pcim_iomap_table will fail. It will return NULL.
> Kernel can run into a NULL-pointer dereference.
> This error check will avoid NULL pointer dereference.
>
> Signed-off-by: Arvind Yadav <[email protected]>
> ---
>  drivers/i2c/busses/i2c-designware-pcidrv.c |    4 ++++
>  1 file changed, 4 insertions(+)
>
> diff --git a/drivers/i2c/busses/i2c-designware-pcidrv.c
> b/drivers/i2c/busses/i2c-designware-pcidrv.c
> index d6423cf..6a1907d 100644
> --- a/drivers/i2c/busses/i2c-designware-pcidrv.c
> +++ b/drivers/i2c/busses/i2c-designware-pcidrv.c
> @@ -235,6 +235,10 @@ static int i2c_dw_pci_probe(struct pci_dev *pdev,
>   dev->controller = controller;
>   dev->get_clk_rate_khz = i2c_dw_get_clk_rate_khz;
>   dev->base = pcim_iomap_table(pdev)[0];
> + if (!dev->base) {
> + dev_err(&pdev->dev, "I/O map table allocation
> failed\n");
> + return -ENOMEM;
> + }

NAK.


--
Andy Shevchenko <[email protected]>
Intel Finland Oy

2016-12-22 17:11:20

by Arvind Yadav

Subject: Re: [v1] i2c: busses: i2c-designware-pcidrv:- Handle return NULL error from pcim_iomap_table

Yes, It will not fail. Sorry for the noise.

Thanks
-Arvind

On Thursday 22 December 2016 08:05 PM, Andy Shevchenko wrote:
> On Thu, 2016-12-22 at 17:09 +0530, Arvind Yadav wrote:
>> Here, If pcim_iomap_table will fail. It will return NULL.
>> Kernel can run into a NULL-pointer dereference.
>> This error check will avoid NULL pointer dereference.
>>
>> Signed-off-by: Arvind Yadav <[email protected]>
>> ---
>> drivers/i2c/busses/i2c-designware-pcidrv.c | 4 ++++
>> 1 file changed, 4 insertions(+)
>>
>> diff --git a/drivers/i2c/busses/i2c-designware-pcidrv.c
>> b/drivers/i2c/busses/i2c-designware-pcidrv.c
>> index d6423cf..6a1907d 100644
>> --- a/drivers/i2c/busses/i2c-designware-pcidrv.c
>> +++ b/drivers/i2c/busses/i2c-designware-pcidrv.c
>> @@ -235,6 +235,10 @@ static int i2c_dw_pci_probe(struct pci_dev *pdev,
>> dev->controller = controller;
>> dev->get_clk_rate_khz = i2c_dw_get_clk_rate_khz;
>> dev->base = pcim_iomap_table(pdev)[0];
>> + if (!dev->base) {
>> + dev_err(&pdev->dev, "I/O map table allocation
>> failed\n");
>> + return -ENOMEM;
>> + }
> NAK.
>
>