Update Linux to v5.4.148

Sourced from [1]

[1] https://cdn.kernel.org/pub/linux/kernel/v5.x/linux-5.4.148.tar.gz

Change-Id: Ib3d26c5ba9b022e2e03533005c4fed4d7c30b61b
Signed-off-by: Olivier Deprez <olivier.deprez@arm.com>
diff --git a/net/bluetooth/l2cap_sock.c b/net/bluetooth/l2cap_sock.c
index a7be8b5..82e76ff 100644
--- a/net/bluetooth/l2cap_sock.c
+++ b/net/bluetooth/l2cap_sock.c
@@ -179,9 +179,17 @@
 	struct l2cap_chan *chan = l2cap_pi(sk)->chan;
 	struct sockaddr_l2 la;
 	int len, err = 0;
+	bool zapped;
 
 	BT_DBG("sk %p", sk);
 
+	lock_sock(sk);
+	zapped = sock_flag(sk, SOCK_ZAPPED);
+	release_sock(sk);
+
+	if (zapped)
+		return -EINVAL;
+
 	if (!addr || alen < offsetofend(struct sockaddr, sa_family) ||
 	    addr->sa_family != AF_BLUETOOTH)
 		return -EINVAL;
@@ -418,6 +426,20 @@
 			break;
 		}
 
+		/* Only BR/EDR modes are supported here */
+		switch (chan->mode) {
+		case L2CAP_MODE_BASIC:
+		case L2CAP_MODE_ERTM:
+		case L2CAP_MODE_STREAMING:
+			break;
+		default:
+			err = -EINVAL;
+			break;
+		}
+
+		if (err < 0)
+			break;
+
 		memset(&opts, 0, sizeof(opts));
 		opts.imtu     = chan->imtu;
 		opts.omtu     = chan->omtu;
@@ -677,10 +699,8 @@
 			break;
 		}
 
-		chan->mode = opts.mode;
-		switch (chan->mode) {
-		case L2CAP_MODE_LE_FLOWCTL:
-			break;
+		/* Only BR/EDR modes are supported here */
+		switch (opts.mode) {
 		case L2CAP_MODE_BASIC:
 			clear_bit(CONF_STATE2_DEVICE, &chan->conf_state);
 			break;
@@ -694,6 +714,10 @@
 			break;
 		}
 
+		if (err < 0)
+			break;
+
+		chan->mode = opts.mode;
 		chan->imtu = opts.imtu;
 		chan->omtu = opts.omtu;
 		chan->fcs  = opts.fcs;
@@ -1042,7 +1066,7 @@
 }
 
 /* Kill socket (only if zapped and orphan)
- * Must be called on unlocked socket.
+ * Must be called on unlocked socket, with l2cap channel lock.
  */
 static void l2cap_sock_kill(struct sock *sk)
 {
@@ -1193,6 +1217,7 @@
 {
 	struct sock *sk = sock->sk;
 	int err;
+	struct l2cap_chan *chan;
 
 	BT_DBG("sock %p, sk %p", sock, sk);
 
@@ -1202,9 +1227,17 @@
 	bt_sock_unlink(&l2cap_sk_list, sk);
 
 	err = l2cap_sock_shutdown(sock, 2);
+	chan = l2cap_pi(sk)->chan;
+
+	l2cap_chan_hold(chan);
+	l2cap_chan_lock(chan);
 
 	sock_orphan(sk);
 	l2cap_sock_kill(sk);
+
+	l2cap_chan_unlock(chan);
+	l2cap_chan_put(chan);
+
 	return err;
 }
 
@@ -1222,12 +1255,15 @@
 		BT_DBG("child chan %p state %s", chan,
 		       state_to_string(chan->state));
 
+		l2cap_chan_hold(chan);
 		l2cap_chan_lock(chan);
+
 		__clear_chan_timer(chan);
 		l2cap_chan_close(chan, ECONNRESET);
-		l2cap_chan_unlock(chan);
-
 		l2cap_sock_kill(sk);
+
+		l2cap_chan_unlock(chan);
+		l2cap_chan_put(chan);
 	}
 }
 
@@ -1332,8 +1368,6 @@
 
 	parent = bt_sk(sk)->parent;
 
-	sock_set_flag(sk, SOCK_ZAPPED);
-
 	switch (chan->state) {
 	case BT_OPEN:
 	case BT_BOUND:
@@ -1360,8 +1394,11 @@
 
 		break;
 	}
-
 	release_sock(sk);
+
+	/* Only zap after cleanup to avoid use after free race */
+	sock_set_flag(sk, SOCK_ZAPPED);
+
 }
 
 static void l2cap_sock_state_change_cb(struct l2cap_chan *chan, int state,
@@ -1467,6 +1504,19 @@
 	sk->sk_state_change(sk);
 }
 
+static int l2cap_sock_filter(struct l2cap_chan *chan, struct sk_buff *skb)
+{
+	struct sock *sk = chan->data;
+
+	switch (chan->mode) {
+	case L2CAP_MODE_ERTM:
+	case L2CAP_MODE_STREAMING:
+		return sk_filter(sk, skb);
+	}
+
+	return 0;
+}
+
 static const struct l2cap_ops l2cap_chan_ops = {
 	.name			= "L2CAP Socket Interface",
 	.new_connection		= l2cap_sock_new_connection_cb,
@@ -1481,6 +1531,7 @@
 	.set_shutdown		= l2cap_sock_set_shutdown_cb,
 	.get_sndtimeo		= l2cap_sock_get_sndtimeo_cb,
 	.alloc_skb		= l2cap_sock_alloc_skb_cb,
+	.filter			= l2cap_sock_filter,
 };
 
 static void l2cap_sock_destruct(struct sock *sk)