[PATCH] mfd: fix a potential NULL pointer dereference

[PATCH] mfd: fix a potential NULL pointer dereference

[Kangjie Lu]

In case devm_kzalloc fails, the fix does NULL check and returns
-ENOMEM upon failure so as to avoid NULL pointer dereference.

Signed-off-by: Kangjie Lu <kjlu@umn.edu>
---
 drivers/mfd/sm501.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/mfd/sm501.c b/drivers/mfd/sm501.c
index a530972c5a7e..e0173bf4b0dc 100644
--- a/drivers/mfd/sm501.c
+++ b/drivers/mfd/sm501.c
@@ -1145,6 +1145,9 @@ static int sm501_register_gpio_i2c_instance(struct sm501_devdata *sm,
 	lookup = devm_kzalloc(&pdev->dev,
 			      sizeof(*lookup) + 3 * sizeof(struct gpiod_lookup),
 			      GFP_KERNEL);
+	if (!lookup)
+		return -ENOMEM;
+
 	lookup->dev_id = "i2c-gpio";
 	if (iic->pin_sda < 32)
 		lookup->table[0].chip_label = "SM501-LOW";
-- 
2.17.1

Re: [PATCH] mfd: fix a potential NULL pointer dereference

[Kangjie Lu]

Hi Lee Jones,

Can you review this patch?

Thanks. 

> On Mar 9, 2019, at 2:04 AM, Kangjie Lu <kjlu@umn.edu> wrote:
> 
> In case devm_kzalloc fails, the fix does NULL check and returns
> -ENOMEM upon failure so as to avoid NULL pointer dereference.
> 
> Signed-off-by: Kangjie Lu <kjlu@umn.edu>
> ---
> drivers/mfd/sm501.c | 3 +++
> 1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/mfd/sm501.c b/drivers/mfd/sm501.c
> index a530972c5a7e..e0173bf4b0dc 100644
> --- a/drivers/mfd/sm501.c
> +++ b/drivers/mfd/sm501.c
> @@ -1145,6 +1145,9 @@ static int sm501_register_gpio_i2c_instance(struct sm501_devdata *sm,
> 	lookup = devm_kzalloc(&pdev->dev,
> 			      sizeof(*lookup) + 3 * sizeof(struct gpiod_lookup),
> 			      GFP_KERNEL);
> +	if (!lookup)
> +		return -ENOMEM;
> +
> 	lookup->dev_id = "i2c-gpio";
> 	if (iic->pin_sda < 32)
> 		lookup->table[0].chip_label = "SM501-LOW";
> -- 
> 2.17.1
> 

Re: [PATCH] mfd: fix a potential NULL pointer dereference

[Lee Jones]

On Fri, 22 Mar 2019, Kangjie Lu wrote:

> Hi Lee Jones,
> 
> Can you review this patch?

Don't poke.

I have a very long list of reviews on my TODO.  Poking only surfaces
your patch to the top of my Inbox, and since I review patches in
reverse chronological order, it puts the review to the back of the
queue.

> > On Mar 9, 2019, at 2:04 AM, Kangjie Lu <kjlu@umn.edu> wrote:
> > 
> > In case devm_kzalloc fails, the fix does NULL check and returns
> > -ENOMEM upon failure so as to avoid NULL pointer dereference.
> > 
> > Signed-off-by: Kangjie Lu <kjlu@umn.edu>
> > ---
> > drivers/mfd/sm501.c | 3 +++
> > 1 file changed, 3 insertions(+)
> > 
> > diff --git a/drivers/mfd/sm501.c b/drivers/mfd/sm501.c
> > index a530972c5a7e..e0173bf4b0dc 100644
> > --- a/drivers/mfd/sm501.c
> > +++ b/drivers/mfd/sm501.c
> > @@ -1145,6 +1145,9 @@ static int sm501_register_gpio_i2c_instance(struct sm501_devdata *sm,
> > 	lookup = devm_kzalloc(&pdev->dev,
> > 			      sizeof(*lookup) + 3 * sizeof(struct gpiod_lookup),
> > 			      GFP_KERNEL);
> > +	if (!lookup)
> > +		return -ENOMEM;
> > +
> > 	lookup->dev_id = "i2c-gpio";
> > 	if (iic->pin_sda < 32)
> > 		lookup->table[0].chip_label = "SM501-LOW";
> 

-- 
Lee Jones [李琼斯]
Linaro Services Technical Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog

Re: [PATCH] mfd: fix a potential NULL pointer dereference

[Mukesh Ojha]

On 3/25/2019 1:26 PM, Lee Jones wrote:
> On Fri, 22 Mar 2019, Kangjie Lu wrote:
>
>> Hi Lee Jones,
>>
>> Can you review this patch?
> Don't poke.
>
> I have a very long list of reviews on my TODO.  Poking only surfaces
> your patch to the top of my Inbox, and since I review patches in
> reverse chronological order, it puts the review to the back of the
> queue.
>
>>> On Mar 9, 2019, at 2:04 AM, Kangjie Lu <kjlu@umn.edu> wrote:
>>>
>>> In case devm_kzalloc fails, the fix does NULL check and returns
>>> -ENOMEM upon failure so as to avoid NULL pointer dereference.
>>>
>>> Signed-off-by: Kangjie Lu <kjlu@umn.edu>
>>> ---
>>> drivers/mfd/sm501.c | 3 +++
>>> 1 file changed, 3 insertions(+)
>>>
>>> diff --git a/drivers/mfd/sm501.c b/drivers/mfd/sm501.c
>>> index a530972c5a7e..e0173bf4b0dc 100644
>>> --- a/drivers/mfd/sm501.c
>>> +++ b/drivers/mfd/sm501.c
>>> @@ -1145,6 +1145,9 @@ static int sm501_register_gpio_i2c_instance(struct sm501_devdata *sm,
>>> 	lookup = devm_kzalloc(&pdev->dev,
>>> 			      sizeof(*lookup) + 3 * sizeof(struct gpiod_lookup),
>>> 			      GFP_KERNEL);
>>> +	if (!lookup)
>>> +		return -ENOMEM;

Seems you are using quite old codebase.
This patch is already there ..

https://elixir.bootlin.com/linux/v5.1-rc2/source/drivers/mfd/sm501.c#L1147

commit ae7b8eda27b3( mfd: sm501: Fix potential NULL pointer dereference )


Thanks,
Mukesh


>>> +
>>> 	lookup->dev_id = "i2c-gpio";
>>> 	if (iic->pin_sda < 32)
>>> 		lookup->table[0].chip_label = "SM501-LOW";

Re: [PATCH] mfd: fix a potential NULL pointer dereference

[Lee Jones]

On Mon, 25 Mar 2019, Mukesh Ojha wrote:

> On 3/25/2019 1:26 PM, Lee Jones wrote:
> > On Fri, 22 Mar 2019, Kangjie Lu wrote:
> > 
> > > Hi Lee Jones,
> > > 
> > > Can you review this patch?
> > Don't poke.
> > 
> > I have a very long list of reviews on my TODO.  Poking only surfaces
> > your patch to the top of my Inbox, and since I review patches in
> > reverse chronological order, it puts the review to the back of the
> > queue.
> > 
> > > > On Mar 9, 2019, at 2:04 AM, Kangjie Lu <kjlu@umn.edu> wrote:
> > > > 
> > > > In case devm_kzalloc fails, the fix does NULL check and returns
> > > > -ENOMEM upon failure so as to avoid NULL pointer dereference.
> > > > 
> > > > Signed-off-by: Kangjie Lu <kjlu@umn.edu>
> > > > ---
> > > > drivers/mfd/sm501.c | 3 +++
> > > > 1 file changed, 3 insertions(+)
> > > > 
> > > > diff --git a/drivers/mfd/sm501.c b/drivers/mfd/sm501.c
> > > > index a530972c5a7e..e0173bf4b0dc 100644
> > > > --- a/drivers/mfd/sm501.c
> > > > +++ b/drivers/mfd/sm501.c
> > > > @@ -1145,6 +1145,9 @@ static int sm501_register_gpio_i2c_instance(struct sm501_devdata *sm,
> > > > 	lookup = devm_kzalloc(&pdev->dev,
> > > > 			      sizeof(*lookup) + 3 * sizeof(struct gpiod_lookup),
> > > > 			      GFP_KERNEL);
> > > > +	if (!lookup)
> > > > +		return -ENOMEM;
> 
> Seems you are using quite old codebase.
> This patch is already there ..
> 
> https://elixir.bootlin.com/linux/v5.1-rc2/source/drivers/mfd/sm501.c#L1147
> 
> commit ae7b8eda27b3( mfd: sm501: Fix potential NULL pointer dereference )

Confirmed.  Dropping this one.

-- 
Lee Jones [李琼斯]
Linaro Services Technical Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog