[PATCH AUTOSEL 5.12 30/49] Bluetooth: use correct lock to prevent UAF of hdev object

Sasha Levin
2021-06-07T16:14:24Z

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

[ Upstream commit e305509e678b3a4af2b3cfd410f409f7cdaabb52 ]

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: Sasha Levin <sashal@kernel.org>
---
net/bluetooth/hci_sock.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/bluetooth/hci_sock.c b/net/bluetooth/hci_sock.c
index 251b9128f530..eed0dd066e12 100644
--- a/net/bluetooth/hci_sock.c
+++ b/net/bluetooth/hci_sock.c
@@ -762,7 +762,7 @@ void hci_sock_dev_event(struct hci_dev *hdev, int event)
/* 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;
@@ -771,7 +771,7 @@ void hci_sock_dev_event(struct hci_dev *hdev, int event)

hci_dev_put(hdev);
}
- bh_unlock_sock(sk);
+ release_sock(sk);
}
read_unlock(&hci_sk_list.lock);
}
--
2.30.2