Commit 9b5c7a5a authored by Rafael J. Wysocki's avatar Rafael J. Wysocki
Browse files

ACPI / PM: Fix possible NULL pointer deref in acpi_pm_device_sleep_state() 



After commit fa1675b5 (ACPI / PM: Rework and clean up
acpi_dev_pm_get_state()) a NULL pointer dereference will take place
if NULL is passed to acpi_pm_device_sleep_state() as the second
argument.

Fix that by avoiding to use the pointer that may be NULL until
it's necessary to store a return value at the location pointed to
by it (if not NULL).

Reported-and-tested-by: default avatarAaron Lu <aaron.lu@intel.com>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent fa1675b5

drivers/acpi/device_pm.c

+8 −4
Original line number Original line Diff line number Diff line
@@ -521,7 +521,7 @@ int acpi_pm_device_sleep_state(struct device *dev, int *d_min_p, int d_max_in) 
{

{

	acpi_handle handle = DEVICE_ACPI_HANDLE(dev);

	acpi_handle handle = DEVICE_ACPI_HANDLE(dev);

	struct acpi_device *adev;

	struct acpi_device *adev;

	int ret, d_max;

	int ret, d_min, d_max;





	if (d_max_in < ACPI_STATE_D0 || d_max_in > ACPI_STATE_D3_COLD)

	if (d_max_in < ACPI_STATE_D0 || d_max_in > ACPI_STATE_D3_COLD)

		return -EINVAL;

		return -EINVAL;
@@ -540,19 +540,23 @@ int acpi_pm_device_sleep_state(struct device *dev, int *d_min_p, int d_max_in) 
	}

	}





	ret = acpi_dev_pm_get_state(dev, adev, acpi_target_system_state(),

	ret = acpi_dev_pm_get_state(dev, adev, acpi_target_system_state(),

				    d_min_p, &d_max);

				    &d_min, &d_max);

	if (ret)

	if (ret)

		return ret;

		return ret;





	if (d_max_in < *d_min_p)

	if (d_max_in < d_min)

		return -EINVAL;

		return -EINVAL;





	if (d_max > d_max_in) {

	if (d_max > d_max_in) {

		for (d_max = d_max_in; d_max > *d_min_p; d_max--) {

		for (d_max = d_max_in; d_max > d_min; d_max--) {

			if (adev->power.states[d_max].flags.valid)

			if (adev->power.states[d_max].flags.valid)

				break;

				break;

		}

		}

	}

	}



	if (d_min_p)

		*d_min_p = d_min;



	return d_max;

	return d_max;

}

}

EXPORT_SYMBOL(acpi_pm_device_sleep_state);

EXPORT_SYMBOL(acpi_pm_device_sleep_state);

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