1 files changed, 44 insertions, 5 deletions

diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
index b510da76170e..f63d9918b15a 100644
--- a/net/bluetooth/l2cap_core.c
+++ b/net/bluetooth/l2cap_core.c
@@ -1340,6 +1340,21 @@ static void l2cap_request_info(struct l2cap_conn *conn)
 		       sizeof(req), &req);
 }
 
+static bool l2cap_check_enc_key_size(struct hci_conn *hcon)
+{
+	/* The minimum encryption key size needs to be enforced by the
+	 * host stack before establishing any L2CAP connections. The
+	 * specification in theory allows a minimum of 1, but to align
+	 * BR/EDR and LE transports, a minimum of 7 is chosen.
+	 *
+	 * This check might also be called for unencrypted connections
+	 * that have no key size requirements. Ensure that the link is
+	 * actually encrypted before enforcing a key size.
+	 */
+	return (!test_bit(HCI_CONN_ENCRYPT, &hcon->flags) ||
+		hcon->enc_key_size >= HCI_MIN_ENC_KEY_SIZE);
+}
+
 static void l2cap_do_start(struct l2cap_chan *chan)
 {
 	struct l2cap_conn *conn = chan->conn;
@@ -1357,9 +1372,14 @@ static void l2cap_do_start(struct l2cap_chan *chan)
 	if (!(conn->info_state & L2CAP_INFO_FEAT_MASK_REQ_DONE))
 		return;
 
-	if (l2cap_chan_check_security(chan, true) &&
-	    __l2cap_no_conn_pending(chan))
+	if (!l2cap_chan_check_security(chan, true) ||
+	    !__l2cap_no_conn_pending(chan))
+		return;
+
+	if (l2cap_check_enc_key_size(conn->hcon))
 		l2cap_start_connection(chan);
+	else
+		__set_chan_timer(chan, L2CAP_DISC_TIMEOUT);
 }
 
 static inline int l2cap_mode_supported(__u8 mode, __u32 feat_mask)
@@ -1438,7 +1458,10 @@ static void l2cap_conn_start(struct l2cap_conn *conn)
 				continue;
 			}
 
-			l2cap_start_connection(chan);
+			if (l2cap_check_enc_key_size(conn->hcon))
+				l2cap_start_connection(chan);
+			else
+				l2cap_chan_close(chan, ECONNREFUSED);
 
 		} else if (chan->state == BT_CONNECT2) {
 			struct l2cap_conn_rsp rsp;
@@ -4361,6 +4384,12 @@ static inline int l2cap_disconnect_rsp(struct l2cap_conn *conn,
 
 	l2cap_chan_lock(chan);
 
+	if (chan->state != BT_DISCONN) {
+		l2cap_chan_unlock(chan);
+		mutex_unlock(&conn->chan_lock);
+		return 0;
+	}
+
 	l2cap_chan_hold(chan);
 	l2cap_chan_del(chan, 0);
 
@@ -6790,6 +6819,16 @@ static int l2cap_le_data_rcv(struct l2cap_chan *chan, struct sk_buff *skb)
 		chan->sdu_len = sdu_len;
 		chan->sdu_last_frag = skb;
 
+		/* Detect if remote is not able to use the selected MPS */
+		if (skb->len + L2CAP_SDULEN_SIZE < chan->mps) {
+			u16 mps_len = skb->len + L2CAP_SDULEN_SIZE;
+
+			/* Adjust the number of credits */
+			BT_DBG("chan->mps %u -> %u", chan->mps, mps_len);
+			chan->mps = mps_len;
+			l2cap_chan_le_send_credits(chan);
+		}
+
 		return 0;
 	}
 
@@ -7455,7 +7494,7 @@ static void l2cap_security_cfm(struct hci_conn *hcon, u8 status, u8 encrypt)
 		}
 
 		if (chan->state == BT_CONNECT) {
-			if (!status)
+			if (!status && l2cap_check_enc_key_size(hcon))
 				l2cap_start_connection(chan);
 			else
 				__set_chan_timer(chan, L2CAP_DISC_TIMEOUT);
@@ -7464,7 +7503,7 @@ static void l2cap_security_cfm(struct hci_conn *hcon, u8 status, u8 encrypt)
 			struct l2cap_conn_rsp rsp;
 			__u16 res, stat;
 
-			if (!status) {
+			if (!status && l2cap_check_enc_key_size(hcon)) {
 				if (test_bit(FLAG_DEFER_SETUP, &chan->flags)) {
 					res = L2CAP_CR_PEND;
 					stat = L2CAP_CS_AUTHOR_PEND;