[PATCH] platform/x86: fujitsu-laptop: add NULL check on devm_kzalloc() return value

[PATCH] platform/x86: fujitsu-laptop: add NULL check on devm_kzalloc() return value

[Gustavo A. R. Silva]

Check return value from call to devm_kzalloc()
in order to prevent a NULL pointer dereference.

This issue was detected using Coccinelle and the following semantic patch:

@@
expression x;
identifier fld;
@@

* x = devm_kzalloc(...);
  ... when != x == NULL
  x->fld

Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>
---
 drivers/platform/x86/fujitsu-laptop.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/drivers/platform/x86/fujitsu-laptop.c b/drivers/platform/x86/fujitsu-laptop.c
index c1a8528..593a350 100644
--- a/drivers/platform/x86/fujitsu-laptop.c
+++ b/drivers/platform/x86/fujitsu-laptop.c
@@ -695,6 +695,9 @@ static int acpi_fujitsu_laptop_leds_register(struct acpi_device *device)
 	if (call_fext_func(device,
 			   FUNC_LEDS, 0x0, 0x0, 0x0) & LOGOLAMP_POWERON) {
 		led = devm_kzalloc(&device->dev, sizeof(*led), GFP_KERNEL);
+		if (!led)
+			return -ENOMEM;
+
 		led->name = "fujitsu::logolamp";
 		led->brightness_set_blocking = logolamp_set;
 		led->brightness_get = logolamp_get;
@@ -707,6 +710,9 @@ static int acpi_fujitsu_laptop_leds_register(struct acpi_device *device)
 			    FUNC_LEDS, 0x0, 0x0, 0x0) & KEYBOARD_LAMPS) &&
 	    (call_fext_func(device, FUNC_BUTTONS, 0x0, 0x0, 0x0) == 0x0)) {
 		led = devm_kzalloc(&device->dev, sizeof(*led), GFP_KERNEL);
+		if (!led)
+			return -ENOMEM;
+
 		led->name = "fujitsu::kblamps";
 		led->brightness_set_blocking = kblamps_set;
 		led->brightness_get = kblamps_get;
@@ -723,6 +729,9 @@ static int acpi_fujitsu_laptop_leds_register(struct acpi_device *device)
 	 */
 	if (call_fext_func(device, FUNC_BUTTONS, 0x0, 0x0, 0x0) & BIT(24)) {
 		led = devm_kzalloc(&device->dev, sizeof(*led), GFP_KERNEL);
+		if (!led)
+			return -ENOMEM;
+
 		led->name = "fujitsu::radio_led";
 		led->brightness_set_blocking = radio_led_set;
 		led->brightness_get = radio_led_get;
@@ -741,6 +750,9 @@ static int acpi_fujitsu_laptop_leds_register(struct acpi_device *device)
 	    (call_fext_func(device,
 			    FUNC_LEDS, 0x2, ECO_LED, 0x0) != UNSUPPORTED_CMD)) {
 		led = devm_kzalloc(&device->dev, sizeof(*led), GFP_KERNEL);
+		if (!led)
+			return -ENOMEM;
+
 		led->name = "fujitsu::eco_led";
 		led->brightness_set_blocking = eco_led_set;
 		led->brightness_get = eco_led_get;
-- 
2.5.0

Re: [PATCH] platform/x86: fujitsu-laptop: add NULL check on devm_kzalloc() return value

[Jonathan Woithe]

On Thu, Jul 06, 2017 at 05:19:02PM -0500, Gustavo A. R. Silva wrote:
> Check return value from call to devm_kzalloc()
> in order to prevent a NULL pointer dereference.
> 
> This issue was detected using Coccinelle and the following semantic patch:
> 
> @@
> expression x;
> identifier fld;
> @@
> 
> * x = devm_kzalloc(...);
>   ... when != x == NULL
>   x->fld
> 
> Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>

These checks should be added in the interest of code correctness. 
devm_kzalloc() can fail (even if it's extremely unlikely in practice) so we
should check for this.

Reviewed-by: Jonathan Woithe <jwoithe@just42.net>

> ---
>  drivers/platform/x86/fujitsu-laptop.c | 12 ++++++++++++
>  1 file changed, 12 insertions(+)
> 
> diff --git a/drivers/platform/x86/fujitsu-laptop.c b/drivers/platform/x86/fujitsu-laptop.c
> index c1a8528..593a350 100644
> --- a/drivers/platform/x86/fujitsu-laptop.c
> +++ b/drivers/platform/x86/fujitsu-laptop.c
> @@ -695,6 +695,9 @@ static int acpi_fujitsu_laptop_leds_register(struct acpi_device *device)
>  	if (call_fext_func(device,
>  			   FUNC_LEDS, 0x0, 0x0, 0x0) & LOGOLAMP_POWERON) {
>  		led = devm_kzalloc(&device->dev, sizeof(*led), GFP_KERNEL);
> +		if (!led)
> +			return -ENOMEM;
> +
>  		led->name = "fujitsu::logolamp";
>  		led->brightness_set_blocking = logolamp_set;
>  		led->brightness_get = logolamp_get;
> @@ -707,6 +710,9 @@ static int acpi_fujitsu_laptop_leds_register(struct acpi_device *device)
>  			    FUNC_LEDS, 0x0, 0x0, 0x0) & KEYBOARD_LAMPS) &&
>  	    (call_fext_func(device, FUNC_BUTTONS, 0x0, 0x0, 0x0) == 0x0)) {
>  		led = devm_kzalloc(&device->dev, sizeof(*led), GFP_KERNEL);
> +		if (!led)
> +			return -ENOMEM;
> +
>  		led->name = "fujitsu::kblamps";
>  		led->brightness_set_blocking = kblamps_set;
>  		led->brightness_get = kblamps_get;
> @@ -723,6 +729,9 @@ static int acpi_fujitsu_laptop_leds_register(struct acpi_device *device)
>  	 */
>  	if (call_fext_func(device, FUNC_BUTTONS, 0x0, 0x0, 0x0) & BIT(24)) {
>  		led = devm_kzalloc(&device->dev, sizeof(*led), GFP_KERNEL);
> +		if (!led)
> +			return -ENOMEM;
> +
>  		led->name = "fujitsu::radio_led";
>  		led->brightness_set_blocking = radio_led_set;
>  		led->brightness_get = radio_led_get;
> @@ -741,6 +750,9 @@ static int acpi_fujitsu_laptop_leds_register(struct acpi_device *device)
>  	    (call_fext_func(device,
>  			    FUNC_LEDS, 0x2, ECO_LED, 0x0) != UNSUPPORTED_CMD)) {
>  		led = devm_kzalloc(&device->dev, sizeof(*led), GFP_KERNEL);
> +		if (!led)
> +			return -ENOMEM;
> +
>  		led->name = "fujitsu::eco_led";
>  		led->brightness_set_blocking = eco_led_set;
>  		led->brightness_get = eco_led_get;
> -- 
> 2.5.0

Re: [PATCH] platform/x86: fujitsu-laptop: add NULL check on devm_kzalloc() return value

[Darren Hart]

On Fri, Jul 07, 2017 at 09:49:00AM +0930, Jonathan Woithe wrote:
> On Thu, Jul 06, 2017 at 05:19:02PM -0500, Gustavo A. R. Silva wrote:
> > Check return value from call to devm_kzalloc()
> > in order to prevent a NULL pointer dereference.
> > 
> > This issue was detected using Coccinelle and the following semantic patch:
> > 
> > @@
> > expression x;
> > identifier fld;
> > @@
> > 
> > * x = devm_kzalloc(...);
> >   ... when != x == NULL
> >   x->fld
> > 
> > Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>
> 
> These checks should be added in the interest of code correctness. 
> devm_kzalloc() can fail (even if it's extremely unlikely in practice) so we
> should check for this.
> 
> Reviewed-by: Jonathan Woithe <jwoithe@just42.net>

Thanks Gustavo and Jonathan,

Queued to testing.

-- 
Darren Hart
VMware Open Source Technology Center

Re: [PATCH] platform/x86: fujitsu-laptop: add NULL check on devm_kzalloc() return value

[Gustavo A. R. Silva]

Hi Darren, Jonathan,

Quoting Darren Hart <dvhart@infradead.org>:

> On Fri, Jul 07, 2017 at 09:49:00AM +0930, Jonathan Woithe wrote:
>> On Thu, Jul 06, 2017 at 05:19:02PM -0500, Gustavo A. R. Silva wrote:
>> > Check return value from call to devm_kzalloc()
>> > in order to prevent a NULL pointer dereference.
>> >
>> > This issue was detected using Coccinelle and the following semantic patch:
>> >
>> > @@
>> > expression x;
>> > identifier fld;
>> > @@
>> >
>> > * x = devm_kzalloc(...);
>> >   ... when != x == NULL
>> >   x->fld
>> >
>> > Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>
>>
>> These checks should be added in the interest of code correctness.
>> devm_kzalloc() can fail (even if it's extremely unlikely in practice) so we
>> should check for this.
>>
>> Reviewed-by: Jonathan Woithe <jwoithe@just42.net>
>
> Thanks Gustavo and Jonathan,
>
> Queued to testing.
>

Glad to help. :)

Thanks
--
Gustavo A. R. Silva