[PATCH v4.4/bluetooth 1/2] Bluetooth: Consolidate encryption handling in hci_encrypt_cfm

[Hans-Christian Noren Egtvedt]

From: Luiz Augusto von Dentz <luiz.von.dentz@xxxxxxxxx>

This makes hci_encrypt_cfm calls hci_connect_cfm in case the connection
state is BT_CONFIG so callers don't have to check the state.

Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@xxxxxxxxx>
Signed-off-by: Marcel Holtmann <marcel@xxxxxxxxxxxx>
(cherry picked from commit 3ca44c16b0dcc764b641ee4ac226909f5c421aa3)
(cherry picked from commit 0a60996c7fa7010ea00d9b62fb6996d908a01ead)
---
AFAICT, fixing CVE 2020-10135 Bluetooth impersonation attacks have been
left out for the 4.4 stable kernel. I cherry picked what I assume are
the appropriate two patches missing from the 4.9 stable kernel. Please
add them to upcoming 4.4 stable releases.

 include/net/bluetooth/hci_core.h | 20 ++++++++++++++++++--
 net/bluetooth/hci_event.c        | 28 +++-------------------------
 2 files changed, 21 insertions(+), 27 deletions(-)

diff --git a/include/net/bluetooth/hci_core.h b/include/net/bluetooth/hci_core.h
index 7c0c83dfe86e..0269a772bfe1 100644
--- a/include/net/bluetooth/hci_core.h
+++ b/include/net/bluetooth/hci_core.h
@@ -1235,10 +1235,26 @@ static inline void hci_auth_cfm(struct hci_conn *conn, __u8 status)
 		conn->security_cfm_cb(conn, status);
 }
 
-static inline void hci_encrypt_cfm(struct hci_conn *conn, __u8 status,
-								__u8 encrypt)
+static inline void hci_encrypt_cfm(struct hci_conn *conn, __u8 status)
 {
 	struct hci_cb *cb;
+	__u8 encrypt;
+
+	if (conn->state == BT_CONFIG) {
+		if (status)
+			conn->state = BT_CONNECTED;
+
+		hci_connect_cfm(conn, status);
+		hci_conn_drop(conn);
+		return;
+	}
+
+	if (!test_bit(HCI_CONN_ENCRYPT, &conn->flags))
+		encrypt = 0x00;
+	else if (test_bit(HCI_CONN_AES_CCM, &conn->flags))
+		encrypt = 0x02;
+	else
+		encrypt = 0x01;
 
 	if (conn->sec_level == BT_SECURITY_SDP)
 		conn->sec_level = BT_SECURITY_LOW;
diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
index 03319ab8a7c6..bb9c13506bca 100644
--- a/net/bluetooth/hci_event.c
+++ b/net/bluetooth/hci_event.c
@@ -2479,7 +2479,7 @@ static void hci_auth_complete_evt(struct hci_dev *hdev, struct sk_buff *skb)
 				     &cp);
 		} else {
 			clear_bit(HCI_CONN_ENCRYPT_PEND, &conn->flags);
-			hci_encrypt_cfm(conn, ev->status, 0x00);
+			hci_encrypt_cfm(conn, ev->status);
 		}
 	}
 
@@ -2565,22 +2565,7 @@ static void read_enc_key_size_complete(struct hci_dev *hdev, u8 status,
 		conn->enc_key_size = rp->key_size;
 	}
 
-	if (conn->state == BT_CONFIG) {
-		conn->state = BT_CONNECTED;
-		hci_connect_cfm(conn, 0);
-		hci_conn_drop(conn);
-	} else {
-		u8 encrypt;
-
-		if (!test_bit(HCI_CONN_ENCRYPT, &conn->flags))
-			encrypt = 0x00;
-		else if (test_bit(HCI_CONN_AES_CCM, &conn->flags))
-			encrypt = 0x02;
-		else
-			encrypt = 0x01;
-
-		hci_encrypt_cfm(conn, 0, encrypt);
-	}
+	hci_encrypt_cfm(conn, 0);
 
 unlock:
 	hci_dev_unlock(hdev);
@@ -2674,14 +2659,7 @@ static void hci_encrypt_change_evt(struct hci_dev *hdev, struct sk_buff *skb)
 	}
 
 notify:
-	if (conn->state == BT_CONFIG) {
-		if (!ev->status)
-			conn->state = BT_CONNECTED;
-
-		hci_connect_cfm(conn, ev->status);
-		hci_conn_drop(conn);
-	} else
-		hci_encrypt_cfm(conn, ev->status, ev->encrypt);
+	hci_encrypt_cfm(conn, ev->status);
 
 unlock:
 	hci_dev_unlock(hdev);
-- 
2.27.0