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amba: 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: 3cf3857134 ("ARM: 8256/1: driver coamba: add device binding path 'driver_override'")
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://patch.msgid.link/20260505133935.3772495-2-dakr@kernel.org
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
This commit is contained in:
Danilo Krummrich
2026-05-05 15:37:21 +02:00
parent 016267b521
commit 1947229f5f
2 changed files with 6 additions and 36 deletions
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37
drivers/amba/bus.c
View File

@@ -82,33 +82,6 @@ static void amba_put_disable_pclk(struct amba_device *pcdev)
}
static ssize_t driver_override_show(struct device *_dev,
struct device_attribute *attr, char *buf)
{
struct amba_device *dev = to_amba_device(_dev);
ssize_t len;
device_lock(_dev);
len = sprintf(buf, "%s\n", dev->driver_override);
device_unlock(_dev);
return len;
}
static ssize_t driver_override_store(struct device *_dev,
struct device_attribute *attr,
const char *buf, size_t count)
{
struct amba_device *dev = to_amba_device(_dev);
int ret;
ret = driver_set_override(_dev, &dev->driver_override, buf, count);
if (ret)
return ret;
return count;
}
static DEVICE_ATTR_RW(driver_override);
#define amba_attr_func(name,fmt,arg...) \
static ssize_t name##_show(struct device *_dev, \
struct device_attribute *attr, char *buf) \
@@ -126,7 +99,6 @@ amba_attr_func(resource, "\t%016llx\t%016llx\t%016lx\n",
static struct attribute *amba_dev_attrs[] = {
&dev_attr_id.attr,
&dev_attr_resource.attr,
&dev_attr_driver_override.attr,
NULL,
};
ATTRIBUTE_GROUPS(amba_dev);
@@ -209,10 +181,11 @@ static int amba_match(struct device *dev, const struct device_driver *drv)
{
struct amba_device *pcdev = to_amba_device(dev);
const struct amba_driver *pcdrv = to_amba_driver(drv);
int ret;
mutex_lock(&pcdev->periphid_lock);
if (!pcdev->periphid) {
int ret = amba_read_periphid(pcdev);
ret = amba_read_periphid(pcdev);
/*
* Returning any error other than -EPROBE_DEFER from bus match
@@ -230,8 +203,9 @@ static int amba_match(struct device *dev, const struct device_driver *drv)
mutex_unlock(&pcdev->periphid_lock);
/* When driver_override is set, only bind to the matching driver */
if (pcdev->driver_override)
return !strcmp(pcdev->driver_override, drv->name);
ret = device_match_driver_override(dev, drv);
if (ret >= 0)
return ret;
return amba_lookup(pcdrv->id_table, pcdev) != NULL;
}
@@ -436,6 +410,7 @@ static const struct dev_pm_ops amba_pm = {
const struct bus_type amba_bustype = {
.name = "amba",
.dev_groups = amba_dev_groups,
.driver_override = true,
.match = amba_match,
.uevent = amba_uevent,
.probe = amba_probe,

5
include/linux/amba/bus.h
View File

@@ -71,11 +71,6 @@ struct amba_device {
unsigned int cid;
struct amba_cs_uci_id uci;
unsigned int irq[AMBA_NR_IRQS];
/*
* 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 amba_driver {