[PATCH 4.19 20/58] Bluetooth: use correct lock to prevent UAF of hdev object

Greg Kroah-Hartman
2021-06-08T18:40:02Z

From: Lin Ma <linma@zju.edu.cn>

commit e305509e678b3a4af2b3cfd410f409f7cdaabb52 upstream.

The hci_sock_dev_event() function will cleanup the hdev object for
sockets even if this object may still be in used within the
hci_sock_bound_ioctl() function, result in UAF vulnerability.

This patch replace the BH context lock to serialize these affairs
and prevent the race condition.

Signed-off-by: Lin Ma <linma@zju.edu.cn>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/bluetooth/hci_sock.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

--- a/net/bluetooth/hci_sock.c
+++ b/net/bluetooth/hci_sock.c
@@ -755,7 +755,7 @@ void hci_sock_dev_event(struct hci_dev *
/* Detach sockets from device */
read_lock(&hci_sk_list.lock);
sk_for_each(sk, &hci_sk_list.head) {
- bh_lock_sock_nested(sk);
+ lock_sock(sk);
if (hci_pi(sk)->hdev == hdev) {
hci_pi(sk)->hdev = NULL;
sk->sk_err = EPIPE;
@@ -764,7 +764,7 @@ void hci_sock_dev_event(struct hci_dev *

hci_dev_put(hdev);
}
- bh_unlock_sock(sk);
+ release_sock(sk);
}
read_unlock(&hci_sk_list.lock);
}