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

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Date: Wed, 14 Feb 2024 08:04:30 +0100
From: Armin Wolf <W_Armin@....de>
To: corentin.chary@...il.com,
	luke@...nes.dev
Cc: hdegoede@...hat.com,
	ilpo.jarvinen@...ux.intel.com,
	platform-driver-x86@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH 2/5] platform/x86: wmi: Check if event data is not NULL

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@....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