Bluetooth: L2CAP: Fix not initializing sk_peer_pid

stable inclusion
from stable-v5.10.94
commit cb5813b0e5918b4ea5a863f2b66458c6aaa0a654
bugzilla: https://gitee.com/openeuler/kernel/issues/I531X9

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=cb5813b0e5918b4ea5a863f2b66458c6aaa0a654

--------------------------------

[ Upstream commit f5ff2910 ]

In order to group sockets being connected using L2CAP_MODE_EXT_FLOWCTL
the pid is used but sk_peer_pid was not being initialized as it is
currently only done for af_unix.

Fixes: b48596d1 ("Bluetooth: L2CAP: Add get_peer_pid callback")
Signed-off-by: NLuiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: NMarcel Holtmann <marcel@holtmann.org>
Signed-off-by: NSasha Levin <sashal@kernel.org>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>
Acked-by: NXie XiuQi <xiexiuqi@huawei.com>

net/bluetooth/l2cap_sock.c

@@ -172,6 +172,21 @@ static int l2cap_sock_bind(struct socket *sock, struct sockaddr *addr, int alen)
 	return err;
 }
 
+static void l2cap_sock_init_pid(struct sock *sk)
+{
+	struct l2cap_chan *chan = l2cap_pi(sk)->chan;
+
+	/* Only L2CAP_MODE_EXT_FLOWCTL ever need to access the PID in order to
+	 * group the channels being requested.
+	 */
+	if (chan->mode != L2CAP_MODE_EXT_FLOWCTL)
+		return;
+
+	spin_lock(&sk->sk_peer_lock);
+	sk->sk_peer_pid = get_pid(task_tgid(current));
+	spin_unlock(&sk->sk_peer_lock);
+}
+
 static int l2cap_sock_connect(struct socket *sock, struct sockaddr *addr,
 			      int alen, int flags)
 {
@@ -243,6 +258,8 @@ static int l2cap_sock_connect(struct socket *sock, struct sockaddr *addr,
 	if (chan->psm && bdaddr_type_is_le(chan->src_type) && !chan->mode)
 		chan->mode = L2CAP_MODE_LE_FLOWCTL;
 
+	l2cap_sock_init_pid(sk);
+
 	err = l2cap_chan_connect(chan, la.l2_psm, __le16_to_cpu(la.l2_cid),
 				 &la.l2_bdaddr, la.l2_bdaddr_type);
 	if (err)
@@ -298,6 +315,8 @@ static int l2cap_sock_listen(struct socket *sock, int backlog)
 		goto done;
 	}
 
+	l2cap_sock_init_pid(sk);
+
 	sk->sk_max_ack_backlog = backlog;
 	sk->sk_ack_backlog = 0;