Bluetooth: L2CAP: Fix not checking l2cap_chan security level

l2cap_check_enc_key_size shall check the security level of the
l2cap_chan rather than the hci_conn since for incoming connection
request that may be different as hci_conn may already been
encrypted using a different security level.

Fixes: 522e9ed ("Bluetooth: l2cap: Check encryption key size on incoming connection")
Signed-off-by: Luiz Augusto von Dentz <[email protected]>

Author: Vudentz

net/bluetooth/l2cap_core.c

@@ -1411,7 +1411,8 @@ static void l2cap_request_info(struct l2cap_conn *conn)
 		       sizeof(req), &req);
 }
 
-static bool l2cap_check_enc_key_size(struct hci_conn *hcon)
+static bool l2cap_check_enc_key_size(struct hci_conn *hcon,
+				     struct l2cap_chan *chan)
 {
 	/* The minimum encryption key size needs to be enforced by the
 	 * host stack before establishing any L2CAP connections. The
@@ -1425,7 +1426,7 @@ static bool l2cap_check_enc_key_size(struct hci_conn *hcon)
 	int min_key_size = hcon->hdev->min_enc_key_size;
 
 	/* On FIPS security level, key size must be 16 bytes */
-	if (hcon->sec_level == BT_SECURITY_FIPS)
+	if (chan->sec_level == BT_SECURITY_FIPS)
 		min_key_size = 16;
 
 	return (!test_bit(HCI_CONN_ENCRYPT, &hcon->flags) ||
@@ -1453,7 +1454,7 @@ static void l2cap_do_start(struct l2cap_chan *chan)
 	    !__l2cap_no_conn_pending(chan))
 		return;
 
-	if (l2cap_check_enc_key_size(conn->hcon))
+	if (l2cap_check_enc_key_size(conn->hcon, chan))
 		l2cap_start_connection(chan);
 	else
 		__set_chan_timer(chan, L2CAP_DISC_TIMEOUT);
@@ -1528,7 +1529,7 @@ static void l2cap_conn_start(struct l2cap_conn *conn)
 				continue;
 			}
 
-			if (l2cap_check_enc_key_size(conn->hcon))
+			if (l2cap_check_enc_key_size(conn->hcon, chan))
 				l2cap_start_connection(chan);
 			else
 				l2cap_chan_close(chan, ECONNREFUSED);
@@ -3992,7 +3993,7 @@ static void l2cap_connect(struct l2cap_conn *conn, struct l2cap_cmd_hdr *cmd,
 	/* Check if the ACL is secure enough (if not SDP) */
 	if (psm != cpu_to_le16(L2CAP_PSM_SDP) &&
 	    (!hci_conn_check_link_mode(conn->hcon) ||
-	    !l2cap_check_enc_key_size(conn->hcon))) {
+	    !l2cap_check_enc_key_size(conn->hcon, pchan))) {
 		conn->disc_reason = HCI_ERROR_AUTH_FAILURE;
 		result = L2CAP_CR_SEC_BLOCK;
 		goto response;
@@ -7352,7 +7353,7 @@ static void l2cap_security_cfm(struct hci_conn *hcon, u8 status, u8 encrypt)
 		}
 
 		if (chan->state == BT_CONNECT) {
-			if (!status && l2cap_check_enc_key_size(hcon))
+			if (!status && l2cap_check_enc_key_size(hcon, chan))
 				l2cap_start_connection(chan);
 			else
 				__set_chan_timer(chan, L2CAP_DISC_TIMEOUT);
@@ -7362,7 +7363,7 @@ static void l2cap_security_cfm(struct hci_conn *hcon, u8 status, u8 encrypt)
 			struct l2cap_conn_rsp rsp;
 			__u16 res, stat;
 
-			if (!status && l2cap_check_enc_key_size(hcon)) {
+			if (!status && l2cap_check_enc_key_size(hcon, chan)) {
 				if (test_bit(FLAG_DEFER_SETUP, &chan->flags)) {
 					res = L2CAP_CR_PEND;
 					stat = L2CAP_CS_AUTHOR_PEND;