From 8746f135bb01872ff412d408ea1aa9ebd328c1f5 Mon Sep 17 00:00:00 2001 From: Luiz Augusto von Dentz Date: Wed, 20 May 2020 14:20:14 -0700 Subject: [PATCH] Bluetooth: Disconnect if E0 is used for Level 4 E0 is not allowed with Level 4: BLUETOOTH CORE SPECIFICATION Version 5.2 | Vol 3, Part C page 1319: '128-bit equivalent strength for link and encryption keys required using FIPS approved algorithms (E0 not allowed, SAFER+ not allowed, and P-192 not allowed; encryption key not shortened' SC enabled: > HCI Event: Read Remote Extended Features (0x23) plen 13 Status: Success (0x00) Handle: 256 Page: 1/2 Features: 0x0b 0x00 0x00 0x00 0x00 0x00 0x00 0x00 Secure Simple Pairing (Host Support) LE Supported (Host) Secure Connections (Host Support) > HCI Event: Encryption Change (0x08) plen 4 Status: Success (0x00) Handle: 256 Encryption: Enabled with AES-CCM (0x02) SC disabled: > HCI Event: Read Remote Extended Features (0x23) plen 13 Status: Success (0x00) Handle: 256 Page: 1/2 Features: 0x03 0x00 0x00 0x00 0x00 0x00 0x00 0x00 Secure Simple Pairing (Host Support) LE Supported (Host) > HCI Event: Encryption Change (0x08) plen 4 Status: Success (0x00) Handle: 256 Encryption: Enabled with E0 (0x01) [May 8 20:23] Bluetooth: hci0: Invalid security: expect AES but E0 was used < HCI Command: Disconnect (0x01|0x0006) plen 3 Handle: 256 Reason: Authentication Failure (0x05) Signed-off-by: Luiz Augusto von Dentz Signed-off-by: Marcel Holtmann --- include/net/bluetooth/hci_core.h | 10 ++++++---- net/bluetooth/hci_conn.c | 17 +++++++++++++++++ net/bluetooth/hci_event.c | 20 ++++++++------------ 3 files changed, 31 insertions(+), 16 deletions(-) diff --git a/include/net/bluetooth/hci_core.h b/include/net/bluetooth/hci_core.h index 77d29341b064..836dc997ff94 100644 --- a/include/net/bluetooth/hci_core.h +++ b/include/net/bluetooth/hci_core.h @@ -1481,11 +1481,13 @@ static inline void hci_encrypt_cfm(struct hci_conn *conn, __u8 status) else encrypt = 0x01; - if (conn->sec_level == BT_SECURITY_SDP) - conn->sec_level = BT_SECURITY_LOW; + if (!status) { + if (conn->sec_level == BT_SECURITY_SDP) + conn->sec_level = BT_SECURITY_LOW; - if (conn->pending_sec_level > conn->sec_level) - conn->sec_level = conn->pending_sec_level; + if (conn->pending_sec_level > conn->sec_level) + conn->sec_level = conn->pending_sec_level; + } mutex_lock(&hci_cb_list_lock); list_for_each_entry(cb, &hci_cb_list, list) { diff --git a/net/bluetooth/hci_conn.c b/net/bluetooth/hci_conn.c index 47f3a45d7dcb..8805d68e65f2 100644 --- a/net/bluetooth/hci_conn.c +++ b/net/bluetooth/hci_conn.c @@ -1322,6 +1322,23 @@ int hci_conn_check_link_mode(struct hci_conn *conn) return 0; } + /* AES encryption is required for Level 4: + * + * BLUETOOTH CORE SPECIFICATION Version 5.2 | Vol 3, Part C + * page 1319: + * + * 128-bit equivalent strength for link and encryption keys + * required using FIPS approved algorithms (E0 not allowed, + * SAFER+ not allowed, and P-192 not allowed; encryption key + * not shortened) + */ + if (conn->sec_level == BT_SECURITY_FIPS && + !test_bit(HCI_CONN_AES_CCM, &conn->flags)) { + bt_dev_err(conn->hdev, + "Invalid security: Missing AES-CCM usage"); + return 0; + } + if (hci_conn_ssp_enabled(conn) && !test_bit(HCI_CONN_ENCRYPT, &conn->flags)) return 0; diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c index e08d4dd9a24e..e060fc9ebb18 100644 --- a/net/bluetooth/hci_event.c +++ b/net/bluetooth/hci_event.c @@ -3065,27 +3065,23 @@ static void hci_encrypt_change_evt(struct hci_dev *hdev, struct sk_buff *skb) clear_bit(HCI_CONN_ENCRYPT_PEND, &conn->flags); + /* Check link security requirements are met */ + if (!hci_conn_check_link_mode(conn)) + ev->status = HCI_ERROR_AUTH_FAILURE; + if (ev->status && conn->state == BT_CONNECTED) { if (ev->status == HCI_ERROR_PIN_OR_KEY_MISSING) set_bit(HCI_CONN_AUTH_FAILURE, &conn->flags); + /* Notify upper layers so they can cleanup before + * disconnecting. + */ + hci_encrypt_cfm(conn, ev->status); hci_disconnect(conn, HCI_ERROR_AUTH_FAILURE); hci_conn_drop(conn); goto unlock; } - /* In Secure Connections Only mode, do not allow any connections - * that are not encrypted with AES-CCM using a P-256 authenticated - * combination key. - */ - if (hci_dev_test_flag(hdev, HCI_SC_ONLY) && - (!test_bit(HCI_CONN_AES_CCM, &conn->flags) || - conn->key_type != HCI_LK_AUTH_COMBINATION_P256)) { - hci_connect_cfm(conn, HCI_ERROR_AUTH_FAILURE); - hci_conn_drop(conn); - goto unlock; - } - /* Try reading the encryption key size for encrypted ACL links */ if (!ev->status && ev->encrypt && conn->type == ACL_LINK) { struct hci_cp_read_enc_key_size cp; -- 2.39.5