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Bluetooth: Add support for SMP phase 3 (key distribution)

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This adds support for generating and distributing all the keys
specified in the third phase of SMP.

This will make possible to re-establish secure connections, resolve
private addresses and sign commands.

For now, the values generated are random.

Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@openbossa.org>
Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>
This commit is contained in:
Vinicius Costa Gomes 2011-07-07 18:59:34 -03:00 committed by Gustavo F. Padovan
parent fadd192e81
commit 7034b911af
3 changed files with 114 additions and 2 deletions
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1
include/net/bluetooth/smp.h
View File

@ -118,5 +118,6 @@ struct smp_cmd_security_req {
/* SMP Commands */
int smp_conn_security(struct l2cap_conn *conn, __u8 sec_level);
int smp_sig_channel(struct l2cap_conn *conn, struct sk_buff *skb);
int smp_distribute_keys(struct l2cap_conn *conn, __u8 force);
#endif /* __SMP_H */

1
net/bluetooth/l2cap_core.c
View File

@ -4103,6 +4103,7 @@ static int l2cap_security_cfm(struct hci_conn *hcon, u8 status, u8 encrypt)
chan->sec_level = hcon->sec_level;
del_timer(&conn->security_timer);
l2cap_chan_ready(sk);
smp_distribute_keys(conn, 0);
}
bh_unlock_sock(sk);

114
net/bluetooth/smp.c
View File

@ -202,8 +202,8 @@ static void build_pairing_cmd(struct l2cap_conn *conn,
cmd->io_capability = conn->hcon->io_capability;
cmd->oob_flag = SMP_OOB_NOT_PRESENT;
cmd->max_key_size = SMP_MAX_ENC_KEY_SIZE;
cmd->init_key_dist = 0x00;
cmd->resp_key_dist = 0x00;
cmd->init_key_dist = SMP_DIST_ENC_KEY | SMP_DIST_ID_KEY | SMP_DIST_SIGN;
cmd->resp_key_dist = SMP_DIST_ENC_KEY | SMP_DIST_ID_KEY | SMP_DIST_SIGN;
cmd->auth_req = authreq;
}
@ -474,6 +474,26 @@ int smp_conn_security(struct l2cap_conn *conn, __u8 sec_level)
return 0;
}
static int smp_cmd_encrypt_info(struct l2cap_conn *conn, struct sk_buff *skb)
{
BT_DBG("conn %p", conn);
/* FIXME: store the ltk */
return 0;
}
static int smp_cmd_master_ident(struct l2cap_conn *conn, struct sk_buff *skb)
{
struct smp_cmd_pairing *paircmd = (void *) &conn->prsp[1];
u8 keydist = paircmd->init_key_dist;
BT_DBG("keydist 0x%x", keydist);
/* FIXME: store ediv and rand */
smp_distribute_keys(conn, 1);
return 0;
}
int smp_sig_channel(struct l2cap_conn *conn, struct sk_buff *skb)
{
__u8 code = skb->data[0];
@ -521,10 +541,20 @@ int smp_sig_channel(struct l2cap_conn *conn, struct sk_buff *skb)
break;
case SMP_CMD_ENCRYPT_INFO:
reason = smp_cmd_encrypt_info(conn, skb);
break;
case SMP_CMD_MASTER_IDENT:
reason = smp_cmd_master_ident(conn, skb);
break;
case SMP_CMD_IDENT_INFO:
case SMP_CMD_IDENT_ADDR_INFO:
case SMP_CMD_SIGN_INFO:
/* Just ignored */
reason = 0;
break;
default:
BT_DBG("Unknown command code 0x%2.2x", code);
@ -541,3 +571,83 @@ done:
kfree_skb(skb);
return err;
}
int smp_distribute_keys(struct l2cap_conn *conn, __u8 force)
{
struct smp_cmd_pairing *req, *rsp;
__u8 *keydist;
BT_DBG("conn %p force %d", conn, force);
if (IS_ERR(conn->hcon->hdev->tfm))
return PTR_ERR(conn->hcon->hdev->tfm);
rsp = (void *) &conn->prsp[1];
/* The responder sends its keys first */
if (!force && conn->hcon->out && (rsp->resp_key_dist & 0x07))
return 0;
req = (void *) &conn->preq[1];
if (conn->hcon->out) {
keydist = &rsp->init_key_dist;
*keydist &= req->init_key_dist;
} else {
keydist = &rsp->resp_key_dist;
*keydist &= req->resp_key_dist;
}
BT_DBG("keydist 0x%x", *keydist);
if (*keydist & SMP_DIST_ENC_KEY) {
struct smp_cmd_encrypt_info enc;
struct smp_cmd_master_ident ident;
__le16 ediv;
get_random_bytes(enc.ltk, sizeof(enc.ltk));
get_random_bytes(&ediv, sizeof(ediv));
get_random_bytes(ident.rand, sizeof(ident.rand));
smp_send_cmd(conn, SMP_CMD_ENCRYPT_INFO, sizeof(enc), &enc);
ident.ediv = cpu_to_le16(ediv);
smp_send_cmd(conn, SMP_CMD_MASTER_IDENT, sizeof(ident), &ident);
*keydist &= ~SMP_DIST_ENC_KEY;
}
if (*keydist & SMP_DIST_ID_KEY) {
struct smp_cmd_ident_addr_info addrinfo;
struct smp_cmd_ident_info idinfo;
/* Send a dummy key */
get_random_bytes(idinfo.irk, sizeof(idinfo.irk));
smp_send_cmd(conn, SMP_CMD_IDENT_INFO, sizeof(idinfo), &idinfo);
/* Just public address */
memset(&addrinfo, 0, sizeof(addrinfo));
bacpy(&addrinfo.bdaddr, conn->src);
smp_send_cmd(conn, SMP_CMD_IDENT_ADDR_INFO, sizeof(addrinfo),
&addrinfo);
*keydist &= ~SMP_DIST_ID_KEY;
}
if (*keydist & SMP_DIST_SIGN) {
struct smp_cmd_sign_info sign;
/* Send a dummy key */
get_random_bytes(sign.csrk, sizeof(sign.csrk));
smp_send_cmd(conn, SMP_CMD_SIGN_INFO, sizeof(sign), &sign);
*keydist &= ~SMP_DIST_SIGN;
}
return 0;
}