[v1] platform/x86: wmi: Fixes for event data handling

[PATCH 2/5] platform/x86: wmi: Check if event data is not NULL

Posted by Armin Wolf 1 year, 12 months ago

WMI event drivers which do not have no_notify_data set expect
that each WMI event contains valid data. Evaluating _WED however
might return no data, which can cause issues with such drivers.

Fix this by validating that evaluating _WED did return data.

Signed-off-by: Armin Wolf <W_Armin@gmx.de>
---
 drivers/platform/x86/wmi.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/drivers/platform/x86/wmi.c b/drivers/platform/x86/wmi.c
index 34d8f55afaad..8a916887c546 100644
--- a/drivers/platform/x86/wmi.c
+++ b/drivers/platform/x86/wmi.c
@@ -1211,6 +1211,7 @@ static void wmi_notify_driver(struct wmi_block *wblock)
 {
 	struct wmi_driver *driver = drv_to_wdrv(wblock->dev.dev.driver);
 	struct acpi_buffer data = { ACPI_ALLOCATE_BUFFER, NULL };
+	union acpi_object *obj = NULL;
 	acpi_status status;

 	if (!driver->no_notify_data) {
@@ -1219,12 +1220,18 @@ static void wmi_notify_driver(struct wmi_block *wblock)
 			dev_warn(&wblock->dev.dev, "Failed to get event data\n");
 			return;
 		}
+
+		obj = data.pointer;
+		if (!obj) {
+			dev_warn(&wblock->dev.dev, "Event contains not event data\n");
+			return;
+		}
 	}

 	if (driver->notify)
-		driver->notify(&wblock->dev, data.pointer);
+		driver->notify(&wblock->dev, obj);

-	kfree(data.pointer);
+	kfree(obj);
 }

 static int wmi_notify_device(struct device *dev, void *data)
--
2.39.2

Re: [PATCH 2/5] platform/x86: wmi: Check if event data is not NULL

Posted by Ilpo Järvinen 1 year, 12 months ago

On Wed, 14 Feb 2024, Armin Wolf wrote:

> WMI event drivers which do not have no_notify_data set expect
> that each WMI event contains valid data. Evaluating _WED however
> might return no data, which can cause issues with such drivers.
> 
> Fix this by validating that evaluating _WED did return data.
> 
> Signed-off-by: Armin Wolf <W_Armin@gmx.de>
> ---
>  drivers/platform/x86/wmi.c | 11 +++++++++--
>  1 file changed, 9 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/platform/x86/wmi.c b/drivers/platform/x86/wmi.c
> index 34d8f55afaad..8a916887c546 100644
> --- a/drivers/platform/x86/wmi.c
> +++ b/drivers/platform/x86/wmi.c
> @@ -1211,6 +1211,7 @@ static void wmi_notify_driver(struct wmi_block *wblock)
>  {
>  	struct wmi_driver *driver = drv_to_wdrv(wblock->dev.dev.driver);
>  	struct acpi_buffer data = { ACPI_ALLOCATE_BUFFER, NULL };
> +	union acpi_object *obj = NULL;
>  	acpi_status status;
> 
>  	if (!driver->no_notify_data) {
> @@ -1219,12 +1220,18 @@ static void wmi_notify_driver(struct wmi_block *wblock)
>  			dev_warn(&wblock->dev.dev, "Failed to get event data\n");
>  			return;
>  		}
> +
> +		obj = data.pointer;
> +		if (!obj) {
> +			dev_warn(&wblock->dev.dev, "Event contains not event data\n");
> +			return;
> +		}
>  	}
> 
>  	if (driver->notify)
> -		driver->notify(&wblock->dev, data.pointer);
> +		driver->notify(&wblock->dev, obj);
> 
> -	kfree(data.pointer);
> +	kfree(obj);

Hi Armin,

While looking into this patch, I failed to connect the mention of 
no_notify_data in the commit message with the code change that does
nothing differently based no_notify_data being set or not, AFAICT.

It could be just that you need to explain things better in the commit 
message, I'm not sure.

-- 
 i.

Re: [PATCH 2/5] platform/x86: wmi: Check if event data is not NULL

Posted by Armin Wolf 1 year, 11 months ago

Am 15.02.24 um 13:31 schrieb Ilpo Järvinen:

> On Wed, 14 Feb 2024, Armin Wolf wrote:
>
>> WMI event drivers which do not have no_notify_data set expect
>> that each WMI event contains valid data. Evaluating _WED however
>> might return no data, which can cause issues with such drivers.
>>
>> Fix this by validating that evaluating _WED did return data.
>>
>> Signed-off-by: Armin Wolf <W_Armin@gmx.de>
>> ---
>>   drivers/platform/x86/wmi.c | 11 +++++++++--
>>   1 file changed, 9 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/platform/x86/wmi.c b/drivers/platform/x86/wmi.c
>> index 34d8f55afaad..8a916887c546 100644
>> --- a/drivers/platform/x86/wmi.c
>> +++ b/drivers/platform/x86/wmi.c
>> @@ -1211,6 +1211,7 @@ static void wmi_notify_driver(struct wmi_block *wblock)
>>   {
>>   	struct wmi_driver *driver = drv_to_wdrv(wblock->dev.dev.driver);
>>   	struct acpi_buffer data = { ACPI_ALLOCATE_BUFFER, NULL };
>> +	union acpi_object *obj = NULL;
>>   	acpi_status status;
>>
>>   	if (!driver->no_notify_data) {
>> @@ -1219,12 +1220,18 @@ static void wmi_notify_driver(struct wmi_block *wblock)
>>   			dev_warn(&wblock->dev.dev, "Failed to get event data\n");
>>   			return;
>>   		}
>> +
>> +		obj = data.pointer;
>> +		if (!obj) {
>> +			dev_warn(&wblock->dev.dev, "Event contains not event data\n");
>> +			return;
>> +		}
>>   	}
>>
>>   	if (driver->notify)
>> -		driver->notify(&wblock->dev, data.pointer);
>> +		driver->notify(&wblock->dev, obj);
>>
>> -	kfree(data.pointer);
>> +	kfree(obj);
> Hi Armin,
>
> While looking into this patch, I failed to connect the mention of
> no_notify_data in the commit message with the code change that does
> nothing differently based no_notify_data being set or not, AFAICT.
>
> It could be just that you need to explain things better in the commit
> message, I'm not sure.

Here the _WED ACPI control method is only evaluated if driver->no_notify_data is not set.
So the returned ACPI object should only be validated in this case, as we pass NULL otherwise.

Armin Wolf

Re: [PATCH 2/5] platform/x86: wmi: Check if event data is not NULL

Posted by Ilpo Järvinen 1 year, 11 months ago

On Thu, 15 Feb 2024, Armin Wolf wrote:

> Am 15.02.24 um 13:31 schrieb Ilpo Järvinen:
> 
> > On Wed, 14 Feb 2024, Armin Wolf wrote:
> > 
> > > WMI event drivers which do not have no_notify_data set expect
> > > that each WMI event contains valid data. Evaluating _WED however
> > > might return no data, which can cause issues with such drivers.
> > > 
> > > Fix this by validating that evaluating _WED did return data.
> > > 
> > > Signed-off-by: Armin Wolf <W_Armin@gmx.de>
> > > ---
> > >   drivers/platform/x86/wmi.c | 11 +++++++++--
> > >   1 file changed, 9 insertions(+), 2 deletions(-)
> > > 
> > > diff --git a/drivers/platform/x86/wmi.c b/drivers/platform/x86/wmi.c
> > > index 34d8f55afaad..8a916887c546 100644
> > > --- a/drivers/platform/x86/wmi.c
> > > +++ b/drivers/platform/x86/wmi.c
> > > @@ -1211,6 +1211,7 @@ static void wmi_notify_driver(struct wmi_block
> > > *wblock)
> > >   {
> > >   	struct wmi_driver *driver = drv_to_wdrv(wblock->dev.dev.driver);
> > >   	struct acpi_buffer data = { ACPI_ALLOCATE_BUFFER, NULL };
> > > +	union acpi_object *obj = NULL;
> > >   	acpi_status status;
> > > 
> > >   	if (!driver->no_notify_data) {
> > > @@ -1219,12 +1220,18 @@ static void wmi_notify_driver(struct wmi_block
> > > *wblock)
> > >   			dev_warn(&wblock->dev.dev, "Failed to get event
> > > data\n");
> > >   			return;
> > >   		}
> > > +
> > > +		obj = data.pointer;
> > > +		if (!obj) {
> > > +			dev_warn(&wblock->dev.dev, "Event contains not event
> > > data\n");
> > > +			return;
> > > +		}
> > >   	}
> > > 
> > >   	if (driver->notify)
> > > -		driver->notify(&wblock->dev, data.pointer);
> > > +		driver->notify(&wblock->dev, obj);
> > > 
> > > -	kfree(data.pointer);
> > > +	kfree(obj);
> > Hi Armin,
> > 
> > While looking into this patch, I failed to connect the mention of
> > no_notify_data in the commit message with the code change that does
> > nothing differently based no_notify_data being set or not, AFAICT.
> > 
> > It could be just that you need to explain things better in the commit
> > message, I'm not sure.
> 
> Here the _WED ACPI control method is only evaluated if driver->no_notify_data
> is not set.
> So the returned ACPI object should only be validated in this case, as we pass
> NULL otherwise.

Yes, I'm sorry, it seems fine. For some reason I was very confused while 
reviewing even if no_notify_data was mentioned right in the previous 
context (maybe Iused some older version of the code while trying to figure 
things out, I dunno).

-- 
 i.