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From:   Sasha Levin <sashal@kernel.org>
To:     linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc:     Lin Ma <linma@zju.edu.cn>, Marcel Holtmann <marcel@holtmann.org>,
        Sasha Levin <sashal@kernel.org>,
        linux-bluetooth@vger.kernel.org, netdev@vger.kernel.org
Subject: [PATCH AUTOSEL 4.9 08/15] Bluetooth: use correct lock to prevent UAF of hdev object
Date:   Mon,  7 Jun 2021 12:15:36 -0400
Message-Id: <20210607161543.3584778-8-sashal@kernel.org>
In-Reply-To: <20210607161543.3584778-1-sashal@kernel.org>
References: <20210607161543.3584778-1-sashal@kernel.org>
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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 44b3146c6117..35f5585188de 100644
--- a/net/bluetooth/hci_sock.c
+++ b/net/bluetooth/hci_sock.c
@@ -750,7 +750,7 @@ 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;
@@ -759,7 +759,7 @@ 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