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i3c: master: Fix use-after-free of master->this

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sysfs attribute callbacks for the master controller device dereference
master->this.  However, master->this is freed in
i3c_master_detach_free_devs() before the master device itself is
released.

As a result, sysfs accesses can dereference a freed master->this
pointer, leading to a use-after-free.

Keep master->this alive until i3c_masterdev_release(), which is called
after the master device and its sysfs state are being torn down. Do not
free master->this as part of the normal device detach path.

On the error path in i3c_master_set_info(), reset master->this and
bus.cur_master to NULL before freeing the allocated device.

Fixes: 3a379bbcea ("i3c: Add core I3C infrastructure")
Cc: stable@vger.kernel.org
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Link: https://patch.msgid.link/20260807145638.168865-5-adrian.hunter@intel.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
This commit is contained in:
Adrian Hunter 2026-08-07 17:56:28 +03:00 committed by Alexandre Belloni
parent 4dc1b3eeba
commit feb0ed7660
1 changed files with 11 additions and 6 deletions
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17
drivers/i3c/master.c
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@ -842,6 +842,11 @@ static struct attribute *i3c_masterdev_attrs[] = {
};
ATTRIBUTE_GROUPS(i3c_masterdev);
static void i3c_master_free_i3c_dev(struct i3c_dev_desc *dev)
{
kfree(dev);
}
static void i3c_masterdev_release(struct device *dev)
{
struct i3c_master_controller *master = dev_to_i3cmaster(dev);
@ -854,6 +859,8 @@ static void i3c_masterdev_release(struct device *dev)
i3c_bus_cleanup(bus);
fwnode_handle_put(dev->fwnode);
i3c_master_free_i3c_dev(master->this);
}
static const struct device_type i3c_masterdev_type = {
@ -1125,11 +1132,6 @@ static void i3c_device_release(struct device *dev)
kfree(i3cdev);
}
static void i3c_master_free_i3c_dev(struct i3c_dev_desc *dev)
{
kfree(dev);
}
static struct i3c_dev_desc *
i3c_master_alloc_i3c_dev(struct i3c_master_controller *master,
const struct i3c_device_info *info)
@ -2266,6 +2268,8 @@ int i3c_master_set_info(struct i3c_master_controller *master,
return 0;
err_free_dev:
master->bus.cur_master = NULL;
master->this = NULL;
i3c_master_free_i3c_dev(i3cdev);
return ret;
@ -2286,7 +2290,8 @@ static void i3c_master_detach_free_devs(struct i3c_master_controller *master)
i3cdev->boardinfo->init_dyn_addr,
I3C_ADDR_SLOT_FREE);
i3c_master_free_i3c_dev(i3cdev);
if (i3cdev != master->this)
i3c_master_free_i3c_dev(i3cdev);
}
list_for_each_entry_safe(i2cdev, i2ctmp, &master->bus.devs.i2c,