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Bluetooth: Read encryption key size for BR/EDR connections

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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@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
This commit is contained in:
Johan Hedberg 2015-06-11 13:52:29 +03:00 committed by Marcel Holtmann
parent 035ad621b6
commit 821f376668
2 changed files with 97 additions and 0 deletions
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10
include/net/bluetooth/hci.h
View File

@ -1202,6 +1202,16 @@ struct hci_rp_read_clock {
__le16 accuracy; __le16 accuracy;
} __packed; } __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 #define HCI_OP_READ_LOCAL_AMP_INFO 0x1409
struct hci_rp_read_local_amp_info { struct hci_rp_read_local_amp_info {
__u8 status; __u8 status;

87
net/bluetooth/hci_event.c
View File

@ -2603,6 +2603,64 @@ unlock:
hci_dev_unlock(hdev); 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) static void hci_encrypt_change_evt(struct hci_dev *hdev, struct sk_buff *skb)
{ {
struct hci_ev_encrypt_change *ev = (void *) skb->data; 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; 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 (conn->state == BT_CONFIG) {
if (!ev->status) if (!ev->status)
conn->state = BT_CONNECTED; conn->state = BT_CONNECTED;