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From:   Sasha Levin <sashal@kernel.org>
To:     linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc:     Nguyen Dinh Phi <phind.uet@gmail.com>,
        syzbot+4c4ffd1e1094dae61035@syzkaller.appspotmail.com,
        Marcel Holtmann <marcel@holtmann.org>,
        Sasha Levin <sashal@kernel.org>, johan.hedberg@gmail.com,
        luiz.dentz@gmail.com, davem@davemloft.net, kuba@kernel.org,
        linux-bluetooth@vger.kernel.org, netdev@vger.kernel.org
Subject: [PATCH AUTOSEL 5.16 001/217] Bluetooth: hci_sock: purge socket queues in the destruct() callback
Date:   Mon, 17 Jan 2022 21:16:04 -0500
Message-Id: <20220118021940.1942199-1-sashal@kernel.org>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

From: Nguyen Dinh Phi <phind.uet@gmail.com>

[ Upstream commit 709fca500067524381e28a5f481882930eebac88 ]

The receive path may take the socket right before hci_sock_release(),
but it may enqueue the packets to the socket queues after the call to
skb_queue_purge(), therefore the socket can be destroyed without clear
its queues completely.

Moving these skb_queue_purge() to the hci_sock_destruct() will fix this
issue, because nothing is referencing the socket at this point.

Signed-off-by: Nguyen Dinh Phi <phind.uet@gmail.com>
Reported-by: syzbot+4c4ffd1e1094dae61035@syzkaller.appspotmail.com
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/bluetooth/hci_sock.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/net/bluetooth/hci_sock.c b/net/bluetooth/hci_sock.c
index d0dad1fafe079..446573a125711 100644
--- a/net/bluetooth/hci_sock.c
+++ b/net/bluetooth/hci_sock.c
@@ -889,10 +889,6 @@ static int hci_sock_release(struct socket *sock)
 	}
 
 	sock_orphan(sk);
-
-	skb_queue_purge(&sk->sk_receive_queue);
-	skb_queue_purge(&sk->sk_write_queue);
-
 	release_sock(sk);
 	sock_put(sk);
 	return 0;
@@ -2058,6 +2054,12 @@ static int hci_sock_getsockopt(struct socket *sock, int level, int optname,
 	return err;
 }
 
+static void hci_sock_destruct(struct sock *sk)
+{
+	skb_queue_purge(&sk->sk_receive_queue);
+	skb_queue_purge(&sk->sk_write_queue);
+}
+
 static const struct proto_ops hci_sock_ops = {
 	.family		= PF_BLUETOOTH,
 	.owner		= THIS_MODULE,
@@ -2111,6 +2113,7 @@ static int hci_sock_create(struct net *net, struct socket *sock, int protocol,
 
 	sock->state = SS_UNCONNECTED;
 	sk->sk_state = BT_OPEN;
+	sk->sk_destruct = hci_sock_destruct;
 
 	bt_sock_link(&hci_sk_list, sk);
 	return 0;
-- 
2.34.1