[lvc-project] [PATCH] Drivers: hv: vmbus: Fix potential NULL pointer dereference in vmbus_acpi_add()

[Fedor Pchelkin]

On Tue, 10. Mar 08:42, Ваторопин Андрей wrote:
> From: Andrey Vatoropin <a.vatoropin at crpt.ru>
> 
> The current driver supports detection via both the ACPI interface and the
> Device Tree interface (OF).
> 
> In the function vmbus_platform_driver_probe() upon driver detection via OF,
> the branch vmbus_device_add() should be executed.
> 
> However, the variable "acpi_disabled" is a global variable that, in general
> equals 0 when CONFIG_ACPI is enabled. Therefore, it may enter another
> branch with vmbus_acpi_add().
> 
> Therefore, in the function vmbus_acpi_add(), when the device is not ACPI,
> the ACPI_COMPANION macro may return a NULL value, and this pointer is then
> dereferenced.
> 
> Add a NULL pointer check for the "device" pointer before dereferencing it.
> 
> Found by Linux Verification Center (linuxtesting.org) with SVACE.
> 
> Fixes: f83705a51275 ("Driver: VMBus: Add Devicetree support")
> Cc: stable at vger.kernel.org
> Signed-off-by: Andrey Vatoropin <a.vatoropin at crpt.ru>
> ---

Для ветки 6.12 понадобится выслать адаптированную версию патча только в
lvc-patches.

>  drivers/hv/vmbus_drv.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
> index bc4fc1951ae1..c9ee3375b524 100644
> --- a/drivers/hv/vmbus_drv.c
> +++ b/drivers/hv/vmbus_drv.c
> @@ -2571,6 +2571,9 @@ static int vmbus_acpi_add(struct platform_device *pdev)
>  	struct acpi_device *ancestor;
>  	struct acpi_device *device = ACPI_COMPANION(&pdev->dev);
>  
> +	if (!device)
> +		return -ENODEV;
> +
>  	vmbus_root_device = &device->dev;
>  
>  	/*
> -- 
> 2.43.0