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platform/wmi: use generic driver_override infrastructure

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When a driver is probed through __driver_attach(), the bus' match()
callback is called without the device lock held, thus accessing the
driver_override field without a lock, which can cause a UAF.

Fix this by using the driver-core driver_override infrastructure taking
care of proper locking internally.

Note that calling match() from __driver_attach() without the device lock
held is intentional. [1]

Link: https://lore.kernel.org/driver-core/DGRGTIRHA62X.3RY09D9SOK77P@kernel.org/ [1]
Reported-by: Gui-Dong Han <hanguidong02@gmail.com>
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=220789
Fixes: 12046f8c77 ("platform/x86: wmi: Add driver_override support")
Reviewed-by: Armin Wolf <W_Armin@gmx.de>
Acked-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://patch.msgid.link/20260324005919.2408620-7-dakr@kernel.org
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
This commit is contained in:
Danilo Krummrich
2026-03-24 01:59:10 +01:00
parent 10a4206a24
commit 8a700b1fc9
2 changed files with 5 additions and 35 deletions
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36
drivers/platform/wmi/core.c
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@@ -842,39 +842,11 @@ static ssize_t expensive_show(struct device *dev,
}
static DEVICE_ATTR_RO(expensive);
static ssize_t driver_override_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
struct wmi_device *wdev = to_wmi_device(dev);
ssize_t ret;
device_lock(dev);
ret = sysfs_emit(buf, "%s\n", wdev->driver_override);
device_unlock(dev);
return ret;
}
static ssize_t driver_override_store(struct device *dev, struct device_attribute *attr,
const char *buf, size_t count)
{
struct wmi_device *wdev = to_wmi_device(dev);
int ret;
ret = driver_set_override(dev, &wdev->driver_override, buf, count);
if (ret < 0)
return ret;
return count;
}
static DEVICE_ATTR_RW(driver_override);
static struct attribute *wmi_attrs[] = {
&dev_attr_modalias.attr,
&dev_attr_guid.attr,
&dev_attr_instance_count.attr,
&dev_attr_expensive.attr,
&dev_attr_driver_override.attr,
NULL
};
ATTRIBUTE_GROUPS(wmi);
@@ -943,7 +915,6 @@ static void wmi_dev_release(struct device *dev)
{
struct wmi_block *wblock = dev_to_wblock(dev);
kfree(wblock->dev.driver_override);
kfree(wblock);
}
@@ -952,10 +923,12 @@ static int wmi_dev_match(struct device *dev, const struct device_driver *driver)
const struct wmi_driver *wmi_driver = to_wmi_driver(driver);
struct wmi_block *wblock = dev_to_wblock(dev);
const struct wmi_device_id *id = wmi_driver->id_table;
int ret;
/* When driver_override is set, only bind to the matching driver */
if (wblock->dev.driver_override)
return !strcmp(wblock->dev.driver_override, driver->name);
ret = device_match_driver_override(dev, driver);
if (ret >= 0)
return ret;
if (id == NULL)
return 0;
@@ -1076,6 +1049,7 @@ static struct class wmi_bus_class = {
static const struct bus_type wmi_bus_type = {
.name = "wmi",
.dev_groups = wmi_groups,
.driver_override = true,
.match = wmi_dev_match,
.uevent = wmi_dev_uevent,
.probe = wmi_dev_probe,