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Drivers: hv: vmbus: 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]

Tested-by: Michael Kelley <mhklinux@outlook.com>
Reviewed-by: Michael Kelley <mhklinux@outlook.com>
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: d765edbb30 ("vmbus: add driver_override support")
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://patch.msgid.link/20260505133935.3772495-4-dakr@kernel.org
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
This commit is contained in:
Danilo Krummrich
2026-05-05 15:37:23 +02:00
parent d541aa1897
commit 331d890012
2 changed files with 10 additions and 38 deletions
Download Patch File Download Diff File Expand all files Collapse all files
drivers/hv/vmbus_drv.c
+10 -33
View File
@@ -538,34 +538,6 @@ static ssize_t device_show(struct device *dev,
}
static DEVICE_ATTR_RO(device);
static ssize_t driver_override_store(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t count)
{
struct hv_device *hv_dev = device_to_hv_device(dev);
int ret;
ret = driver_set_override(dev, &hv_dev->driver_override, buf, count);
if (ret)
return ret;
return count;
}
static ssize_t driver_override_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct hv_device *hv_dev = device_to_hv_device(dev);
ssize_t len;
device_lock(dev);
len = sysfs_emit(buf, "%s\n", hv_dev->driver_override);
device_unlock(dev);
return len;
}
static DEVICE_ATTR_RW(driver_override);
/* Set up per device attributes in /sys/bus/vmbus/devices/<bus device> */
static struct attribute *vmbus_dev_attrs[] = {
&dev_attr_id.attr,
@@ -596,7 +568,6 @@ static struct attribute *vmbus_dev_attrs[] = {
&dev_attr_channel_vp_mapping.attr,
&dev_attr_vendor.attr,
&dev_attr_device.attr,
&dev_attr_driver_override.attr,
NULL,
};
@@ -708,9 +679,11 @@ static const struct hv_vmbus_device_id *hv_vmbus_get_id(const struct hv_driver *
{
const guid_t *guid = &dev->dev_type;
const struct hv_vmbus_device_id *id;
int ret;
/* When driver_override is set, only bind to the matching driver */
if (dev->driver_override && strcmp(dev->driver_override, drv->name))
/* If a driver override is set, only bind to the matching driver */
ret = device_match_driver_override(&dev->device, &drv->driver);
if (ret == 0)
return NULL;
/* Look at the dynamic ids first, before the static ones */
@@ -718,8 +691,11 @@ static const struct hv_vmbus_device_id *hv_vmbus_get_id(const struct hv_driver *
if (!id)
id = hv_vmbus_dev_match(drv->id_table, guid);
/* driver_override will always match, send a dummy id */
if (!id && dev->driver_override)
/*
* If there's a matching driver override, this function should succeed,
* thus return a dummy device ID if no matching ID is found.
*/
if (!id && ret > 0)
id = &vmbus_device_null;
return id;
@@ -1021,6 +997,7 @@ static const struct dev_pm_ops vmbus_pm = {
/* The one and only one */
static const struct bus_type hv_bus = {
.name = "vmbus",
.driver_override = true,
.match = vmbus_match,
.shutdown = vmbus_shutdown,
.remove = vmbus_remove,
include/linux/hyperv.h
-5
View File
@@ -1272,11 +1272,6 @@ struct hv_device {
u16 device_id;
struct device device;
/*
* Driver name to force a match. Do not set directly, because core
* frees it. Use driver_set_override() to set or clear it.
*/
const char *driver_override;
struct vmbus_channel *channel;
struct kset *channels_kset;