From 821f37666815c9f3a7a4d195ce9184ad4d084942 Mon Sep 17 00:00:00 2001 From: Johan Hedberg Date: Thu, 11 Jun 2015 13:52:29 +0300 Subject: Bluetooth: Read encryption key size for BR/EDR connections Since Bluetooth 3.0 there's a HCI command available for reading the encryption key size of an BR/EDR connection. This information is essential e.g. for generating an LTK using SMP over BR/EDR, so store it as part of struct hci_conn. Signed-off-by: Johan Hedberg Signed-off-by: Marcel Holtmann --- net/bluetooth/hci_event.c | 87 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 87 insertions(+) (limited to 'net/bluetooth/hci_event.c') diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c index 62934151431b..88c57b12a222 100644 --- a/net/bluetooth/hci_event.c +++ b/net/bluetooth/hci_event.c @@ -2603,6 +2603,64 @@ unlock: hci_dev_unlock(hdev); } +static void read_enc_key_size_complete(struct hci_dev *hdev, u8 status, + u16 opcode, struct sk_buff *skb) +{ + const struct hci_rp_read_enc_key_size *rp; + struct hci_conn *conn; + u16 handle; + + BT_DBG("%s status 0x%02x", hdev->name, status); + + if (!skb || skb->len < sizeof(*rp)) { + BT_ERR("%s invalid HCI Read Encryption Key Size response", + hdev->name); + return; + } + + rp = (void *)skb->data; + handle = le16_to_cpu(rp->handle); + + hci_dev_lock(hdev); + + conn = hci_conn_hash_lookup_handle(hdev, handle); + if (!conn) + goto unlock; + + /* If we fail to read the encryption key size, assume maximum + * (which is the same we do also when this HCI command isn't + * supported. + */ + if (rp->status) { + BT_ERR("%s failed to read key size for handle %u", hdev->name, + handle); + conn->enc_key_size = HCI_LINK_KEY_SIZE; + } else { + 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 (conn->type == ACL_LINK && + test_bit(HCI_CONN_AES_CCM, &conn->flags)) + encrypt = 0x02; + else + encrypt = 0x01; + + hci_encrypt_cfm(conn, 0, encrypt); + } + +unlock: + hci_dev_unlock(hdev); +} + static void hci_encrypt_change_evt(struct hci_dev *hdev, struct sk_buff *skb) { struct hci_ev_encrypt_change *ev = (void *) skb->data; @@ -2662,6 +2720,35 @@ static void hci_encrypt_change_evt(struct hci_dev *hdev, struct sk_buff *skb) 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; + struct hci_request req; + + /* Only send HCI_Read_Encryption_Key_Size if the + * controller really supports it. If it doesn't, assume + * the default size (16). + */ + if (!(hdev->commands[20] & 0x10)) { + conn->enc_key_size = HCI_LINK_KEY_SIZE; + goto notify; + } + + hci_req_init(&req, hdev); + + cp.handle = cpu_to_le16(conn->handle); + hci_req_add(&req, HCI_OP_READ_ENC_KEY_SIZE, sizeof(cp), &cp); + + if (hci_req_run_skb(&req, read_enc_key_size_complete)) { + BT_ERR("Sending HCI Read Encryption Key Size failed"); + conn->enc_key_size = HCI_LINK_KEY_SIZE; + goto notify; + } + + goto unlock; + } + +notify: if (conn->state == BT_CONFIG) { if (!ev->status) conn->state = BT_CONNECTED; -- cgit v1.2.3