[PATCH 1/2] platform/x86: msi-wmi-platform: Only load on MSI devices

[Armin Wolf <W_Armin@gmx.de>]

It turns out that the GUID used by the msi-wmi-platform driver
(ABBC0F60-8EA1-11D1-00A0-C90629100000) is not unique, but was instead
copied from the WIndows Driver Samples. This means that this driver
could load on devices from other manufacturers that also copied this
GUID, potentially causing hardware errors.

Prevent this by only loading on devices whitelisted via DMI. The DMI
matches where taken from the msi-ec driver.

Fixes: 9c0beb6b29e7 ("platform/x86: wmi: Add MSI WMI Platform driver")
Signed-off-by: Armin Wolf <W_Armin@gmx.de>
---
 drivers/platform/x86/Kconfig            |  1 +
 drivers/platform/x86/msi-wmi-platform.c | 41 ++++++++++++++++++++++++-
 2 files changed, 41 insertions(+), 1 deletion(-)

diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
index 46e62feeda3c..d96728a0f18d 100644
--- a/drivers/platform/x86/Kconfig
+++ b/drivers/platform/x86/Kconfig
@@ -545,6 +545,7 @@ config MSI_WMI
 config MSI_WMI_PLATFORM
 	tristate "MSI WMI Platform features"
 	depends on ACPI_WMI
+	depends on DMI
 	depends on HWMON
 	help
 	  Say Y here if you want to have support for WMI-based platform features
diff --git a/drivers/platform/x86/msi-wmi-platform.c b/drivers/platform/x86/msi-wmi-platform.c
index dc5e9878cb68..bd2687828a2e 100644
--- a/drivers/platform/x86/msi-wmi-platform.c
+++ b/drivers/platform/x86/msi-wmi-platform.c
@@ -14,6 +14,7 @@
 #include <linux/debugfs.h>
 #include <linux/device.h>
 #include <linux/device/driver.h>
+#include <linux/dmi.h>
 #include <linux/errno.h>
 #include <linux/hwmon.h>
 #include <linux/kernel.h>
@@ -448,7 +449,45 @@ static struct wmi_driver msi_wmi_platform_driver = {
 	.probe = msi_wmi_platform_probe,
 	.no_singleton = true,
 };
-module_wmi_driver(msi_wmi_platform_driver);
+
+/*
+ * MSI reused the WMI GUID from the WMI-ACPI sample code provided by Microsoft,
+ * so other manufacturers might use it as well for their WMI-ACPI implementations.
+ */
+static const struct dmi_system_id msi_wmi_platform_whitelist[] __initconst = {
+	{
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "MICRO-STAR INT"),
+		},
+	},
+	{
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "Micro-Star International"),
+		},
+	},
+	{ }
+};
+
+static int __init msi_wmi_platform_module_init(void)
+{
+	if (!dmi_check_system(msi_wmi_platform_whitelist)) {
+		if (!force)
+			return -ENODEV;
+
+		pr_warn("Ignoring DMI whitelist\n");
+	}
+
+	return wmi_driver_register(&msi_wmi_platform_driver);
+}
+
+static void __exit msi_wmi_platform_module_exit(void)
+{
+	wmi_driver_unregister(&msi_wmi_platform_driver);
+}
+
+module_init(msi_wmi_platform_module_init);
+module_exit(msi_wmi_platform_module_exit);
+
 
 MODULE_AUTHOR("Armin Wolf <W_Armin@gmx.de>");
 MODULE_DESCRIPTION("MSI WMI platform features");
-- 
2.39.5