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vdpa: 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: 539fec78ed ("vdpa: add driver_override support")
Acked-by: Eugenio Pérez <eperezma@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Link: https://patch.msgid.link/20260324005919.2408620-9-dakr@kernel.org
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
This commit is contained in:
Danilo Krummrich
2026-03-24 01:59:12 +01:00
parent 8a700b1fc9
commit 85bb534ff1
2 changed files with 5 additions and 47 deletions
Download Patch File Download Diff File Expand all files Collapse all files

48
drivers/vdpa/vdpa.c
View File

@@ -67,57 +67,20 @@ static void vdpa_dev_remove(struct device *d)
static int vdpa_dev_match(struct device *dev, const struct device_driver *drv)
{
struct vdpa_device *vdev = dev_to_vdpa(dev);
int ret;
/* Check override first, and if set, only use the named driver */
if (vdev->driver_override)
return strcmp(vdev->driver_override, drv->name) == 0;
ret = device_match_driver_override(dev, drv);
if (ret >= 0)
return ret;
/* Currently devices must be supported by all vDPA bus drivers */
return 1;
}
static ssize_t driver_override_store(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t count)
{
struct vdpa_device *vdev = dev_to_vdpa(dev);
int ret;
ret = driver_set_override(dev, &vdev->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 vdpa_device *vdev = dev_to_vdpa(dev);
ssize_t len;
device_lock(dev);
len = sysfs_emit(buf, "%s\n", vdev->driver_override);
device_unlock(dev);
return len;
}
static DEVICE_ATTR_RW(driver_override);
static struct attribute *vdpa_dev_attrs[] = {
&dev_attr_driver_override.attr,
NULL,
};
static const struct attribute_group vdpa_dev_group = {
.attrs = vdpa_dev_attrs,
};
__ATTRIBUTE_GROUPS(vdpa_dev);
static const struct bus_type vdpa_bus = {
.name = "vdpa",
.dev_groups = vdpa_dev_groups,
.driver_override = true,
.match = vdpa_dev_match,
.probe = vdpa_dev_probe,
.remove = vdpa_dev_remove,
@@ -132,7 +95,6 @@ static void vdpa_release_dev(struct device *d)
ops->free(vdev);
ida_free(&vdpa_index_ida, vdev->index);
kfree(vdev->driver_override);
kfree(vdev);
}

4
include/linux/vdpa.h
View File

@@ -72,9 +72,6 @@ struct vdpa_mgmt_dev;
* struct vdpa_device - representation of a vDPA device
* @dev: underlying device
* @vmap: the metadata passed to upper layer to be used for mapping
* @driver_override: driver name to force a match; do not set directly,
* because core frees it; use driver_set_override() to
* set or clear it.
* @config: the configuration ops for this device.
* @map: the map ops for this device
* @cf_lock: Protects get and set access to configuration layout.
@@ -90,7 +87,6 @@ struct vdpa_mgmt_dev;
struct vdpa_device {
struct device dev;
union virtio_map vmap;
const char *driver_override;
const struct vdpa_config_ops *config;
const struct virtio_map_ops *map;
struct rw_semaphore cf_lock; /* Protects get/set config */