From: Johan Hedberg <johan.hedberg@xxxxxxxxx>
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 <johan.hedberg@xxxxxxxxx>
---
include/net/bluetooth/hci.h | 10 ++++++
net/bluetooth/hci_event.c | 87 +++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 97 insertions(+)
diff --git a/include/net/bluetooth/hci.h b/include/net/bluetooth/hci.h
index d95da83cb1b0..7ca6690355ea 100644
--- a/include/net/bluetooth/hci.h
+++ b/include/net/bluetooth/hci.h
@@ -1202,6 +1202,16 @@ struct hci_rp_read_clock {
__le16 accuracy;
} __packed;
+#define HCI_OP_READ_ENC_KEY_SIZE 0x1408
+struct hci_cp_read_enc_key_size {
+ __le16 handle;
+} __packed;
+struct hci_rp_read_enc_key_size {
+ __u8 status;
+ __le16 handle;
+ __u8 key_size;
+} __packed;
+
#define HCI_OP_READ_LOCAL_AMP_INFO 0x1409
struct hci_rp_read_local_amp_info {
__u8 status;
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;
--
2.4.3
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