linux-kernel - [PATCH] driver: base: fix UAF when driver

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Date:   Wed, 11 May 2022 20:43:36 +0800
From:   Schspa Shi <schspa@...il.com>
To:     gregkh@...uxfoundation.org, rafael@...nel.org
Cc:     ming.lei@...onical.com, linux-kernel@...r.kernel.org,
        Schspa Shi <schspa@...il.com>
Subject: [PATCH] driver: base: fix UAF when driver_attach failed

When driver_attach(drv); failed, the driver_private will be freed.
But it has been added to the bus, which caused a UAF.

To fix it, we need to delete it from the bus when failed.

Fixes: 190888ac01d0 ("driver core: fix possible missing of device probe")

Signed-off-by: Schspa Shi <schspa@...il.com>
---
 drivers/base/bus.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/base/bus.c b/drivers/base/bus.c
index 97936ec49bde..7ca47e5b3c1f 100644
--- a/drivers/base/bus.c
+++ b/drivers/base/bus.c
@@ -617,7 +617,7 @@ int bus_add_driver(struct device_driver *drv)
 	if (drv->bus->p->drivers_autoprobe) {
 		error = driver_attach(drv);
 		if (error)
-			goto out_unregister;
+			goto out_del_list;
 	}
 	module_add_driver(drv->owner, drv);
 
@@ -644,6 +644,8 @@ int bus_add_driver(struct device_driver *drv)
 
 	return 0;
 
+out_del_list:
+	klist_del(&priv->knode_bus);
 out_unregister:
 	kobject_put(&priv->kobj);
 	/* drv->p is freed in driver_release()  */
-- 
2.29.0