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rpmsg: 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: e950604782 ("rpmsg: Introduce a driver override mechanism")
Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://patch.msgid.link/20260505133935.3772495-5-dakr@kernel.org
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
This commit is contained in:
Danilo Krummrich 2026-05-05 15:37:24 +02:00
parent 331d890012
commit 55ced13c42
4 changed files with 7 additions and 43 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
drivers/rpmsg/qcom_glink_native.c
View File

@ -1626,7 +1626,6 @@ static void qcom_glink_rpdev_release(struct device *dev)
{
struct rpmsg_device *rpdev = to_rpmsg_device(dev);
kfree(rpdev->driver_override);
kfree(rpdev);
}
@ -1862,7 +1861,6 @@ static void qcom_glink_device_release(struct device *dev)
/* Release qcom_glink_alloc_channel() reference */
kref_put(&channel->refcount, qcom_glink_channel_release);
kfree(rpdev->driver_override);
kfree(rpdev);
}

43
drivers/rpmsg/rpmsg_core.c
View File

@ -358,33 +358,6 @@ rpmsg_show_attr(src, src, "0x%x\n");
rpmsg_show_attr(dst, dst, "0x%x\n");
rpmsg_show_attr(announce, announce ? "true" : "false", "%s\n");
static ssize_t driver_override_store(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t count)
{
struct rpmsg_device *rpdev = to_rpmsg_device(dev);
int ret;
ret = driver_set_override(dev, &rpdev->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 rpmsg_device *rpdev = to_rpmsg_device(dev);
ssize_t len;
device_lock(dev);
len = sysfs_emit(buf, "%s\n", rpdev->driver_override);
device_unlock(dev);
return len;
}
static DEVICE_ATTR_RW(driver_override);
static ssize_t modalias_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
@ -405,7 +378,6 @@ static struct attribute *rpmsg_dev_attrs[] = {
&dev_attr_dst.attr,
&dev_attr_src.attr,
&dev_attr_announce.attr,
&dev_attr_driver_override.attr,
NULL,
};
ATTRIBUTE_GROUPS(rpmsg_dev);
@ -424,9 +396,11 @@ static int rpmsg_dev_match(struct device *dev, const struct device_driver *drv)
const struct rpmsg_driver *rpdrv = to_rpmsg_driver(drv);
const struct rpmsg_device_id *ids = rpdrv->id_table;
unsigned int i;
int ret;
if (rpdev->driver_override)
return !strcmp(rpdev->driver_override, drv->name);
ret = device_match_driver_override(dev, drv);
if (ret >= 0)
return ret;
if (ids)
for (i = 0; ids[i].name[0]; i++)
@ -535,6 +509,7 @@ static const struct bus_type rpmsg_bus = {
.name = "rpmsg",
.match = rpmsg_dev_match,
.dev_groups = rpmsg_dev_groups,
.driver_override = true,
.uevent = rpmsg_uevent,
.probe = rpmsg_dev_probe,
.remove = rpmsg_dev_remove,
@ -560,11 +535,9 @@ int rpmsg_register_device_override(struct rpmsg_device *rpdev,
device_initialize(dev);
if (driver_override) {
ret = driver_set_override(dev, &rpdev->driver_override,
driver_override,
strlen(driver_override));
ret = device_set_driver_override(dev, driver_override);
if (ret) {
dev_err(dev, "device_set_override failed: %d\n", ret);
dev_err(dev, "device_set_driver_override() failed: %d\n", ret);
put_device(dev);
return ret;
}
@ -573,8 +546,6 @@ int rpmsg_register_device_override(struct rpmsg_device *rpdev,
ret = device_add(dev);
if (ret) {
dev_err(dev, "device_add failed: %d\n", ret);
kfree(rpdev->driver_override);
rpdev->driver_override = NULL;
put_device(dev);
}

1
drivers/rpmsg/virtio_rpmsg_bus.c
View File

@ -374,7 +374,6 @@ static void virtio_rpmsg_release_device(struct device *dev)
struct rpmsg_device *rpdev = to_rpmsg_device(dev);
struct virtio_rpmsg_channel *vch = to_virtio_rpmsg_channel(rpdev);
kfree(rpdev->driver_override);
kfree(vch);
}

4
include/linux/rpmsg.h
View File

@ -41,9 +41,6 @@ struct rpmsg_channel_info {
* rpmsg_device - device that belong to the rpmsg bus
* @dev: the device struct
* @id: device id (used to match between rpmsg drivers and devices)
* @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.
* @src: local address
* @dst: destination address
* @ept: the rpmsg endpoint of this channel
@ -53,7 +50,6 @@ struct rpmsg_channel_info {
struct rpmsg_device {
struct device dev;
struct rpmsg_device_id id;
const char *driver_override;
u32 src;
u32 dst;
struct rpmsg_endpoint *ept;