[PATCH-v5 0/6] Bluetooth: Add MITM protection to LE-SMP

[PATCH-v5 0/6] Bluetooth: Add MITM protection to LE-SMP

[Brian Gix]

Mods made per Gustavo's request: Moved function Prototypes to Header
in the patch that they were created.

Also some mods to the blkcipher clean-up, and added a key NULL check
to handling of incoming SMP User Response.

-- 
Brian Gix
bgix@codeaurora.org
Employee of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum

[PATCH-v5 1/6] Bluetooth: Add User Passkey Response handling

[Brian Gix]

For some MITM protection pairing scenarios, the user is
required to enter or accept a 6 digit passkey.

Signed-off-by: Brian Gix <bgix@codeaurora.org>
---
 include/net/bluetooth/hci_core.h |    5 +++
 net/bluetooth/mgmt.c             |   74 +++++++++++++++++++++++++++++++++++++-
 2 files changed, 78 insertions(+), 1 deletions(-)

diff --git a/include/net/bluetooth/hci_core.h b/include/net/bluetooth/hci_core.h
index 1795257..e7b2e25 100644
--- a/include/net/bluetooth/hci_core.h
+++ b/include/net/bluetooth/hci_core.h
@@ -933,6 +933,11 @@ int mgmt_user_confirm_reply_complete(struct hci_dev *hdev, bdaddr_t *bdaddr,
 								u8 status);
 int mgmt_user_confirm_neg_reply_complete(struct hci_dev *hdev,
 						bdaddr_t *bdaddr, u8 status);
+int mgmt_user_passkey_request(struct hci_dev *hdev, bdaddr_t *bdaddr);
+int mgmt_user_passkey_reply_complete(struct hci_dev *hdev, bdaddr_t *bdaddr,
+								u8 status);
+int mgmt_user_passkey_neg_reply_complete(struct hci_dev *hdev,
+						bdaddr_t *bdaddr, u8 status);
 int mgmt_auth_failed(struct hci_dev *hdev, bdaddr_t *bdaddr, u8 status);
 int mgmt_set_local_name_complete(struct hci_dev *hdev, u8 *name, u8 status);
 int mgmt_read_local_oob_data_reply_complete(struct hci_dev *hdev, u8 *hash,
diff --git a/net/bluetooth/mgmt.c b/net/bluetooth/mgmt.c
index c06a05c..7a23f21 100644
--- a/net/bluetooth/mgmt.c
+++ b/net/bluetooth/mgmt.c
@@ -1618,7 +1618,15 @@ static int user_pairing_resp(struct sock *sk, u16 index, bdaddr_t *bdaddr,
 	}
 
 	/* Continue with pairing via HCI */
-	err = hci_send_cmd(hdev, hci_op, sizeof(*bdaddr), bdaddr);
+	if (hci_op == HCI_OP_USER_PASSKEY_REPLY) {
+		struct hci_cp_user_passkey_reply cp;
+
+		bacpy(&cp.bdaddr, bdaddr);
+		cp.passkey = passkey;
+		err = hci_send_cmd(hdev, hci_op, sizeof(cp), &cp);
+	} else
+		err = hci_send_cmd(hdev, hci_op, sizeof(*bdaddr), bdaddr);
+
 	if (err < 0)
 		mgmt_pending_remove(cmd);
 
@@ -1660,6 +1668,37 @@ static int user_confirm_neg_reply(struct sock *sk, u16 index, void *data,
 			HCI_OP_USER_CONFIRM_NEG_REPLY, 0);
 }
 
+static int user_passkey_reply(struct sock *sk, u16 index, void *data, u16 len)
+{
+	struct mgmt_cp_user_passkey_reply *cp = (void *) data;
+
+	BT_DBG("");
+
+	if (len != sizeof(*cp))
+		return cmd_status(sk, index, MGMT_OP_USER_PASSKEY_REPLY,
+									EINVAL);
+
+	return user_pairing_resp(sk, index, &cp->bdaddr,
+			MGMT_OP_USER_PASSKEY_REPLY,
+			HCI_OP_USER_PASSKEY_REPLY, cp->passkey);
+}
+
+static int user_passkey_neg_reply(struct sock *sk, u16 index, void *data,
+									u16 len)
+{
+	struct mgmt_cp_user_passkey_neg_reply *cp = (void *) data;
+
+	BT_DBG("");
+
+	if (len != sizeof(*cp))
+		return cmd_status(sk, index, MGMT_OP_USER_PASSKEY_NEG_REPLY,
+									EINVAL);
+
+	return user_pairing_resp(sk, index, &cp->bdaddr,
+			MGMT_OP_USER_PASSKEY_NEG_REPLY,
+			HCI_OP_USER_PASSKEY_NEG_REPLY, 0);
+}
+
 static int set_local_name(struct sock *sk, u16 index, unsigned char *data,
 								u16 len)
 {
@@ -2117,6 +2156,13 @@ int mgmt_control(struct sock *sk, struct msghdr *msg, size_t msglen)
 		err = user_confirm_neg_reply(sk, index, buf + sizeof(*hdr),
 									len);
 		break;
+	case MGMT_OP_USER_PASSKEY_REPLY:
+		err = user_passkey_reply(sk, index, buf + sizeof(*hdr), len);
+		break;
+	case MGMT_OP_USER_PASSKEY_NEG_REPLY:
+		err = user_passkey_neg_reply(sk, index, buf + sizeof(*hdr),
+									len);
+		break;
 	case MGMT_OP_SET_LOCAL_NAME:
 		err = set_local_name(sk, index, buf + sizeof(*hdr), len);
 		break;
@@ -2477,6 +2523,18 @@ int mgmt_user_confirm_request(struct hci_dev *hdev, bdaddr_t *bdaddr,
 									NULL);
 }
 
+int mgmt_user_passkey_request(struct hci_dev *hdev, bdaddr_t *bdaddr)
+{
+	struct mgmt_ev_user_passkey_request ev;
+
+	BT_DBG("%s", hdev->name);
+
+	bacpy(&ev.bdaddr, bdaddr);
+
+	return mgmt_event(MGMT_EV_USER_PASSKEY_REQUEST, hdev, &ev, sizeof(ev),
+									NULL);
+}
+
 static int user_pairing_resp_complete(struct hci_dev *hdev, bdaddr_t *bdaddr,
 							u8 status, u8 opcode)
 {
@@ -2511,6 +2569,20 @@ int mgmt_user_confirm_neg_reply_complete(struct hci_dev *hdev,
 					MGMT_OP_USER_CONFIRM_NEG_REPLY);
 }
 
+int mgmt_user_passkey_reply_complete(struct hci_dev *hdev, bdaddr_t *bdaddr,
+								u8 status)
+{
+	return user_pairing_resp_complete(hdev, bdaddr, status,
+						MGMT_OP_USER_PASSKEY_REPLY);
+}
+
+int mgmt_user_passkey_neg_reply_complete(struct hci_dev *hdev,
+						bdaddr_t *bdaddr, u8 status)
+{
+	return user_pairing_resp_complete(hdev, bdaddr, status,
+					MGMT_OP_USER_PASSKEY_NEG_REPLY);
+}
+
 int mgmt_auth_failed(struct hci_dev *hdev, bdaddr_t *bdaddr, u8 status)
 {
 	struct mgmt_ev_auth_failed ev;
-- 
1.7.7.2

-- 
Brian Gix
bgix@codeaurora.org
Employee of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum 

[PATCH-v5 2/6] Bluetooth: Add HCI User Passkey Req Evt handling

[Brian Gix]

Some MITM scenarios require handling of the User Passkey Request event,
by querying the user, and passing the response back.

Signed-off-by: Brian Gix <bgix@codeaurora.org>
---
 net/bluetooth/hci_event.c |   58 +++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 58 insertions(+), 0 deletions(-)

diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
index dfe6fbc..980da08 100644
--- a/net/bluetooth/hci_event.c
+++ b/net/bluetooth/hci_event.c
@@ -931,6 +931,37 @@ static void hci_cc_user_confirm_neg_reply(struct hci_dev *hdev,
 	hci_dev_unlock(hdev);
 }
 
+static void hci_cc_user_passkey_reply(struct hci_dev *hdev, struct sk_buff *skb)
+{
+	struct hci_rp_user_confirm_reply *rp = (void *) skb->data;
+
+	BT_DBG("%s status 0x%x", hdev->name, rp->status);
+
+	hci_dev_lock(hdev);
+
+	if (test_bit(HCI_MGMT, &hdev->flags))
+		mgmt_user_passkey_reply_complete(hdev, &rp->bdaddr,
+								rp->status);
+
+	hci_dev_unlock(hdev);
+}
+
+static void hci_cc_user_passkey_neg_reply(struct hci_dev *hdev,
+							struct sk_buff *skb)
+{
+	struct hci_rp_user_confirm_reply *rp = (void *) skb->data;
+
+	BT_DBG("%s status 0x%x", hdev->name, rp->status);
+
+	hci_dev_lock(hdev);
+
+	if (test_bit(HCI_MGMT, &hdev->flags))
+		mgmt_user_passkey_neg_reply_complete(hdev, &rp->bdaddr,
+								rp->status);
+
+	hci_dev_unlock(hdev);
+}
+
 static void hci_cc_read_local_oob_data_reply(struct hci_dev *hdev,
 							struct sk_buff *skb)
 {
@@ -2015,6 +2046,14 @@ static inline void hci_cmd_complete_evt(struct hci_dev *hdev, struct sk_buff *sk
 		hci_cc_user_confirm_neg_reply(hdev, skb);
 		break;
 
+	case HCI_OP_USER_PASSKEY_REPLY:
+		hci_cc_user_passkey_reply(hdev, skb);
+		break;
+
+	case HCI_OP_USER_PASSKEY_NEG_REPLY:
+		hci_cc_user_passkey_neg_reply(hdev, skb);
+		break;
+
 	case HCI_OP_LE_SET_SCAN_ENABLE:
 		hci_cc_le_set_scan_enable(hdev, skb);
 		break;
@@ -2774,6 +2813,21 @@ unlock:
 	hci_dev_unlock(hdev);
 }
 
+static inline void hci_user_passkey_request_evt(struct hci_dev *hdev,
+							struct sk_buff *skb)
+{
+	struct hci_ev_user_passkey_req *ev = (void *) skb->data;
+
+	BT_DBG("%s", hdev->name);
+
+	hci_dev_lock(hdev);
+
+	if (test_bit(HCI_MGMT, &hdev->flags))
+		mgmt_user_passkey_request(hdev, &ev->bdaddr);
+
+	hci_dev_unlock(hdev);
+}
+
 static inline void hci_simple_pair_complete_evt(struct hci_dev *hdev, struct sk_buff *skb)
 {
 	struct hci_ev_simple_pair_complete *ev = (void *) skb->data;
@@ -3113,6 +3167,10 @@ void hci_event_packet(struct hci_dev *hdev, struct sk_buff *skb)
 		hci_user_confirm_request_evt(hdev, skb);
 		break;
 
+	case HCI_EV_USER_PASSKEY_REQUEST:
+		hci_user_passkey_request_evt(hdev, skb);
+		break;
+
 	case HCI_EV_SIMPLE_PAIR_COMPLETE:
 		hci_simple_pair_complete_evt(hdev, skb);
 		break;
-- 
1.7.7.2

-- 
Brian Gix
bgix@codeaurora.org
Employee of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum 

[PATCH-v5 3/6] Bluetooth: Cleanup blkcipher on SMP termination

[Brian Gix]

The blkcipher must be freed to avoid memory leak.

Signed-off-by: Brian Gix <bgix@codeaurora.org>
---
 net/bluetooth/smp.c |   10 +++++++++-
 1 files changed, 9 insertions(+), 1 deletions(-)

diff --git a/net/bluetooth/smp.c b/net/bluetooth/smp.c
index 94e94ca..b9af488 100644
--- a/net/bluetooth/smp.c
+++ b/net/bluetooth/smp.c
@@ -379,7 +379,15 @@ static struct smp_chan *smp_chan_create(struct l2cap_conn *conn)
 
 void smp_chan_destroy(struct l2cap_conn *conn)
 {
-	kfree(conn->smp_chan);
+	struct smp_chan *smp = conn->smp_chan;
+
+	clear_bit(HCI_CONN_LE_SMP_PEND, &conn->hcon->pend);
+
+	if (smp->tfm)
+		crypto_free_blkcipher(smp->tfm);
+
+	kfree(smp);
+	conn->smp_chan = NULL;
 	hci_conn_put(conn->hcon);
 }
 
-- 
1.7.7.2

-- 
Brian Gix
bgix@codeaurora.org
Employee of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum 

[PATCH-v5 4/6] Bluetooth: Centralize SMP pairing failure handling

[Brian Gix]

Signed-off-by: Brian Gix <bgix@codeaurora.org>
---
 net/bluetooth/smp.c |   22 ++++++++++++++++------
 1 files changed, 16 insertions(+), 6 deletions(-)

diff --git a/net/bluetooth/smp.c b/net/bluetooth/smp.c
index b9af488..0b96737 100644
--- a/net/bluetooth/smp.c
+++ b/net/bluetooth/smp.c
@@ -232,6 +232,18 @@ static u8 check_enc_key_size(struct l2cap_conn *conn, __u8 max_key_size)
 	return 0;
 }
 
+static void smp_failure(struct l2cap_conn *conn, u8 reason, u8 send)
+{
+	if (send)
+		smp_send_cmd(conn, SMP_CMD_PAIRING_FAIL, sizeof(reason),
+								&reason);
+
+	clear_bit(HCI_CONN_ENCRYPT_PEND, &conn->hcon->pend);
+	mgmt_auth_failed(conn->hcon->hdev, conn->dst, reason);
+	del_timer(&conn->security_timer);
+	smp_chan_destroy(conn);
+}
+
 static void confirm_work(struct work_struct *work)
 {
 	struct smp_chan *smp = container_of(work, struct smp_chan, confirm);
@@ -270,8 +282,7 @@ static void confirm_work(struct work_struct *work)
 	return;
 
 error:
-	smp_send_cmd(conn, SMP_CMD_PAIRING_FAIL, sizeof(reason), &reason);
-	smp_chan_destroy(conn);
+	smp_failure(conn, reason, 1);
 }
 
 static void random_work(struct work_struct *work)
@@ -354,8 +365,7 @@ static void random_work(struct work_struct *work)
 	return;
 
 error:
-	smp_send_cmd(conn, SMP_CMD_PAIRING_FAIL, sizeof(reason), &reason);
-	smp_chan_destroy(conn);
+	smp_failure(conn, reason, 1);
 }
 
 static struct smp_chan *smp_chan_create(struct l2cap_conn *conn)
@@ -655,6 +665,7 @@ int smp_sig_channel(struct l2cap_conn *conn, struct sk_buff *skb)
 		break;
 
 	case SMP_CMD_PAIRING_FAIL:
+		smp_failure(conn, skb->data[0], 0);
 		reason = 0;
 		err = -EPERM;
 		break;
@@ -700,8 +711,7 @@ int smp_sig_channel(struct l2cap_conn *conn, struct sk_buff *skb)
 
 done:
 	if (reason)
-		smp_send_cmd(conn, SMP_CMD_PAIRING_FAIL, sizeof(reason),
-								&reason);
+		smp_failure(conn, reason, 1);
 
 	kfree_skb(skb);
 	return err;
-- 
1.7.7.2

-- 
Brian Gix
bgix@codeaurora.org
Employee of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum 

Re: [PATCH-v5 4/6] Bluetooth: Centralize SMP pairing failure handling

[Gustavo Padovan]

Hi Brian,

* Brian Gix <bgix@codeaurora.org> [2011-11-23 08:28:36 -0800]:

> Signed-off-by: Brian Gix <bgix@codeaurora.org>
> ---
>  net/bluetooth/smp.c |   22 ++++++++++++++++------
>  1 files changed, 16 insertions(+), 6 deletions(-)
> 
> diff --git a/net/bluetooth/smp.c b/net/bluetooth/smp.c
> index b9af488..0b96737 100644
> --- a/net/bluetooth/smp.c
> +++ b/net/bluetooth/smp.c
> @@ -232,6 +232,18 @@ static u8 check_enc_key_size(struct l2cap_conn *conn, __u8 max_key_size)
>  	return 0;
>  }
>  
> +static void smp_failure(struct l2cap_conn *conn, u8 reason, u8 send)
> +{
> +	if (send)
> +		smp_send_cmd(conn, SMP_CMD_PAIRING_FAIL, sizeof(reason),
> +								&reason);
> +
> +	clear_bit(HCI_CONN_ENCRYPT_PEND, &conn->hcon->pend);
> +	mgmt_auth_failed(conn->hcon->hdev, conn->dst, reason);
> +	del_timer(&conn->security_timer);
> +	smp_chan_destroy(conn);
> +}
> +
>  static void confirm_work(struct work_struct *work)
>  {
>  	struct smp_chan *smp = container_of(work, struct smp_chan, confirm);
> @@ -270,8 +282,7 @@ static void confirm_work(struct work_struct *work)
>  	return;
>  
>  error:
> -	smp_send_cmd(conn, SMP_CMD_PAIRING_FAIL, sizeof(reason), &reason);
> -	smp_chan_destroy(conn);
> +	smp_failure(conn, reason, 1);
>  }
>  
>  static void random_work(struct work_struct *work)
> @@ -354,8 +365,7 @@ static void random_work(struct work_struct *work)
>  	return;
>  
>  error:
> -	smp_send_cmd(conn, SMP_CMD_PAIRING_FAIL, sizeof(reason), &reason);
> -	smp_chan_destroy(conn);
> +	smp_failure(conn, reason, 1);
>  }
>  
>  static struct smp_chan *smp_chan_create(struct l2cap_conn *conn)
> @@ -655,6 +665,7 @@ int smp_sig_channel(struct l2cap_conn *conn, struct sk_buff *skb)
>  		break;
>  
>  	case SMP_CMD_PAIRING_FAIL:
> +		smp_failure(conn, skb->data[0], 0);
>  		reason = 0;
>  		err = -EPERM;
>  		break;
> @@ -700,8 +711,7 @@ int smp_sig_channel(struct l2cap_conn *conn, struct sk_buff *skb)
>  
>  done:
>  	if (reason)
> -		smp_send_cmd(conn, SMP_CMD_PAIRING_FAIL, sizeof(reason),
> -								&reason);
> +		smp_failure(conn, reason, 1);
>  
>  	kfree_skb(skb);
>  	return err;

Patch 1 to 4 were applied. Thanks.

	Gustavo

[PATCH-v5 5/6] Bluetooth: Add MITM mechanism to LE-SMP

[Brian Gix]

To achive Man-In-The-Middle (MITM) level security with Low Energy,
we have to enable User Passkey Comparison.  This commit modifies the
hard-coded JUST-WORKS pairing mechanism to support query via the MGMT
interface of Passkey comparison and User Confirmation.

Signed-off-by: Brian Gix <bgix@codeaurora.org>
---
 include/net/bluetooth/hci_core.h |    1 +
 include/net/bluetooth/smp.h      |    3 +
 net/bluetooth/smp.c              |  228 ++++++++++++++++++++++++++++++++++----
 3 files changed, 210 insertions(+), 22 deletions(-)

diff --git a/include/net/bluetooth/hci_core.h b/include/net/bluetooth/hci_core.h
index e7b2e25..4aa417c 100644
--- a/include/net/bluetooth/hci_core.h
+++ b/include/net/bluetooth/hci_core.h
@@ -312,6 +312,7 @@ struct hci_conn {
 	struct hci_dev	*hdev;
 	void		*l2cap_data;
 	void		*sco_data;
+	void		*smp_conn;
 
 	struct hci_conn	*link;
 
diff --git a/include/net/bluetooth/smp.h b/include/net/bluetooth/smp.h
index 15b97d5..43b6c49 100644
--- a/include/net/bluetooth/smp.h
+++ b/include/net/bluetooth/smp.h
@@ -124,6 +124,8 @@ struct smp_chan {
 	u8		pcnf[16]; /* SMP Pairing Confirm */
 	u8		tk[16]; /* SMP Temporary Key */
 	u8		smp_key_size;
+	u8		smp_tk_valid;
+	u8		smp_cfm_pending;
 	struct crypto_blkcipher	*tfm;
 	struct work_struct confirm;
 	struct work_struct random;
@@ -134,6 +136,7 @@ struct smp_chan {
 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);
+int smp_user_confirm_reply(struct hci_conn *conn, u16 mgmt_op, __le32 passkey);
 
 void smp_chan_destroy(struct l2cap_conn *conn);
 
diff --git a/net/bluetooth/smp.c b/net/bluetooth/smp.c
index 0b96737..e1df0a2 100644
--- a/net/bluetooth/smp.c
+++ b/net/bluetooth/smp.c
@@ -23,6 +23,7 @@
 #include <net/bluetooth/bluetooth.h>
 #include <net/bluetooth/hci_core.h>
 #include <net/bluetooth/l2cap.h>
+#include <net/bluetooth/mgmt.h>
 #include <net/bluetooth/smp.h>
 #include <linux/crypto.h>
 #include <linux/scatterlist.h>
@@ -188,24 +189,46 @@ static void smp_send_cmd(struct l2cap_conn *conn, u8 code, u16 len, void *data)
 					msecs_to_jiffies(SMP_TIMEOUT));
 }
 
+static __u8 authreq_to_seclevel(__u8 authreq)
+{
+	if (authreq & SMP_AUTH_MITM)
+		return BT_SECURITY_HIGH;
+	else
+		return BT_SECURITY_MEDIUM;
+}
+
+static __u8 seclevel_to_authreq(__u8 sec_level)
+{
+	switch (sec_level) {
+	case BT_SECURITY_HIGH:
+		return SMP_AUTH_MITM | SMP_AUTH_BONDING;
+	case BT_SECURITY_MEDIUM:
+		return SMP_AUTH_BONDING;
+	default:
+		return SMP_AUTH_NONE;
+	}
+}
+
 static void build_pairing_cmd(struct l2cap_conn *conn,
 				struct smp_cmd_pairing *req,
 				struct smp_cmd_pairing *rsp,
 				__u8 authreq)
 {
-	u8 dist_keys;
+	u8 all_keys = 0;
+	u8 dist_keys = 0;
 
-	dist_keys = 0;
 	if (test_bit(HCI_PAIRABLE, &conn->hcon->hdev->flags)) {
 		dist_keys = SMP_DIST_ENC_KEY;
 		authreq |= SMP_AUTH_BONDING;
+	} else {
+		authreq &= ~SMP_AUTH_BONDING;
 	}
 
 	if (rsp == NULL) {
 		req->io_capability = conn->hcon->io_capability;
 		req->oob_flag = SMP_OOB_NOT_PRESENT;
 		req->max_key_size = SMP_MAX_ENC_KEY_SIZE;
-		req->init_key_dist = dist_keys;
+		req->init_key_dist = all_keys;
 		req->resp_key_dist = dist_keys;
 		req->auth_req = authreq;
 		return;
@@ -214,7 +237,7 @@ static void build_pairing_cmd(struct l2cap_conn *conn,
 	rsp->io_capability = conn->hcon->io_capability;
 	rsp->oob_flag = SMP_OOB_NOT_PRESENT;
 	rsp->max_key_size = SMP_MAX_ENC_KEY_SIZE;
-	rsp->init_key_dist = req->init_key_dist & dist_keys;
+	rsp->init_key_dist = req->init_key_dist & all_keys;
 	rsp->resp_key_dist = req->resp_key_dist & dist_keys;
 	rsp->auth_req = authreq;
 }
@@ -244,6 +267,93 @@ static void smp_failure(struct l2cap_conn *conn, u8 reason, u8 send)
 	smp_chan_destroy(conn);
 }
 
+#define JUST_WORKS	0x00
+#define JUST_CFM	0x01
+#define REQ_PASSKEY	0x02
+#define CFM_PASSKEY	0x03
+#define REQ_OOB		0x04
+#define OVERLAP		0xFF
+
+static const u8	gen_method[5][5] = {
+	{JUST_WORKS,  JUST_CFM,    REQ_PASSKEY, JUST_WORKS, REQ_PASSKEY},
+	{JUST_WORKS,  JUST_CFM,    REQ_PASSKEY, JUST_WORKS, REQ_PASSKEY},
+	{CFM_PASSKEY, CFM_PASSKEY, REQ_PASSKEY, JUST_WORKS, CFM_PASSKEY},
+	{JUST_WORKS,  JUST_CFM,    JUST_WORKS,  JUST_WORKS, JUST_CFM},
+	{CFM_PASSKEY, CFM_PASSKEY, REQ_PASSKEY, JUST_WORKS, OVERLAP}
+};
+
+static int tk_request(struct l2cap_conn *conn, u8 remote_oob, u8 auth,
+						u8 local_io, u8 remote_io)
+{
+	struct hci_conn *hcon = conn->hcon;
+	struct smp_chan *smp = conn->smp_chan;
+	u8 method;
+	u32 passkey = 0;
+	int ret = 0;
+
+	/* Initialize key to JUST WORKS */
+	memset(smp->tk, 0, sizeof(smp->tk));
+	smp->smp_tk_valid = 0;
+
+	BT_DBG("tk_request: auth:%d lcl:%d rem:%d", auth, local_io, remote_io);
+
+	/* If neither side wants MITM, use JUST WORKS */
+	/* If either side has unknown io_caps, use JUST_WORKS */
+	if (!(auth & SMP_AUTH_MITM) ||
+			local_io > SMP_IO_KEYBOARD_DISPLAY ||
+			remote_io > SMP_IO_KEYBOARD_DISPLAY) {
+		auth &= ~SMP_AUTH_MITM;
+		smp->smp_tk_valid = 1;
+		return 0;
+	}
+
+	/* MITM is now officially requested, but not required */
+	/* Determine what we need (if anything) from the agent */
+	method = gen_method[local_io][remote_io];
+
+	if (method == JUST_WORKS || method == JUST_CFM)
+		auth &= ~SMP_AUTH_MITM;
+
+	/* Don't bother confirming unbonded JUST_WORKS */
+	if (!(auth & SMP_AUTH_BONDING) && method == JUST_CFM) {
+		smp->smp_tk_valid = 1;
+		return 0;
+	} else if (method == JUST_WORKS) {
+		smp->smp_tk_valid = 1;
+		return 0;
+	} else if (method == OVERLAP) {
+		if (hcon->link_mode & HCI_LM_MASTER)
+			method = CFM_PASSKEY;
+		else
+			method = REQ_PASSKEY;
+	}
+
+	if (method == CFM_PASSKEY) {
+		u8 key[16];
+		/* Generate a passkey for display. It is not valid until
+		 * confirmed.
+		 */
+		memset(key, 0, sizeof(key));
+		get_random_bytes(&passkey, sizeof(passkey));
+		passkey %= 1000000;
+		put_unaligned_le32(passkey, key);
+		swap128(key, smp->tk);
+		BT_DBG("PassKey: %d", passkey);
+	}
+
+	hci_dev_lock(hcon->hdev);
+
+	if (method == REQ_PASSKEY)
+		ret = mgmt_user_passkey_request(hcon->hdev, conn->dst);
+	else
+		ret = mgmt_user_confirm_request(hcon->hdev, conn->dst,
+						cpu_to_le32(passkey), 0);
+
+	hci_dev_unlock(hcon->hdev);
+
+	return ret;
+}
+
 static void confirm_work(struct work_struct *work)
 {
 	struct smp_chan *smp = container_of(work, struct smp_chan, confirm);
@@ -276,6 +386,8 @@ static void confirm_work(struct work_struct *work)
 		goto error;
 	}
 
+	smp->smp_cfm_pending = 0;
+
 	swap128(res, cp.confirm_val);
 	smp_send_cmd(smp->conn, SMP_CMD_PAIRING_CONFIRM, sizeof(cp), &cp);
 
@@ -381,6 +493,7 @@ static struct smp_chan *smp_chan_create(struct l2cap_conn *conn)
 
 	smp->conn = conn;
 	conn->smp_chan = smp;
+	conn->hcon->smp_conn = conn;
 
 	hci_conn_hold(conn->hcon);
 
@@ -398,18 +511,67 @@ void smp_chan_destroy(struct l2cap_conn *conn)
 
 	kfree(smp);
 	conn->smp_chan = NULL;
+	conn->hcon->smp_conn = NULL;
 	hci_conn_put(conn->hcon);
 }
 
+int smp_user_confirm_reply(struct hci_conn *hcon, u16 mgmt_op, __le32 passkey)
+{
+	struct l2cap_conn *conn = hcon->smp_conn;
+	struct smp_chan *smp;
+	u32 value;
+	u8 key[16];
+	u8 reason = 0;
+	int ret = 0;
+
+	BT_DBG("");
+
+	if (!conn)
+		return -ENOTCONN;
+
+	smp = conn->smp_chan;
+
+	switch (mgmt_op) {
+	case MGMT_OP_USER_PASSKEY_REPLY:
+		value = le32_to_cpu(passkey);
+		memset(key, 0, sizeof(key));
+		BT_DBG("PassKey: %d", value);
+		put_unaligned_le32(value, key);
+		swap128(key, smp->tk);
+		/* Fall Through */
+	case MGMT_OP_USER_CONFIRM_REPLY:
+		smp->smp_tk_valid = 1;
+		break;
+	default:
+		ret = -EOPNOTSUPP;
+		/* Fall Through */
+	case MGMT_OP_USER_PASSKEY_NEG_REPLY:
+	case MGMT_OP_USER_CONFIRM_NEG_REPLY:
+		reason = SMP_PASSKEY_ENTRY_FAILED;
+		break;
+	}
+
+	if (reason)
+		smp_failure(conn, reason, 1);
+	else if (smp->smp_cfm_pending)
+		queue_work(hcon->hdev->workqueue, &smp->confirm);
+
+	return ret;
+}
+
 static u8 smp_cmd_pairing_req(struct l2cap_conn *conn, struct sk_buff *skb)
 {
 	struct smp_cmd_pairing rsp, *req = (void *) skb->data;
 	struct smp_chan *smp;
 	u8 key_size;
+	u8 auth = SMP_AUTH_NONE;
 	int ret;
 
 	BT_DBG("conn %p", conn);
 
+	if (conn->hcon->link_mode & HCI_LM_MASTER)
+		return SMP_CMD_NOTSUPP;
+
 	if (!test_and_set_bit(HCI_CONN_LE_SMP_PEND, &conn->hcon->pend))
 		smp = smp_chan_create(conn);
 
@@ -419,19 +581,16 @@ static u8 smp_cmd_pairing_req(struct l2cap_conn *conn, struct sk_buff *skb)
 	memcpy(&smp->preq[1], req, sizeof(*req));
 	skb_pull(skb, sizeof(*req));
 
-	if (req->oob_flag)
-		return SMP_OOB_NOT_AVAIL;
+	/* We didn't start the pairing, so match remote */
+	if (req->auth_req & SMP_AUTH_BONDING)
+		auth = req->auth_req;
 
-	/* We didn't start the pairing, so no requirements */
-	build_pairing_cmd(conn, req, &rsp, SMP_AUTH_NONE);
+	build_pairing_cmd(conn, req, &rsp, auth);
 
 	key_size = min(req->max_key_size, rsp.max_key_size);
 	if (check_enc_key_size(conn, key_size))
 		return SMP_ENC_KEY_SIZE;
 
-	/* Just works */
-	memset(smp->tk, 0, sizeof(smp->tk));
-
 	ret = smp_rand(smp->prnd);
 	if (ret)
 		return SMP_UNSPECIFIED;
@@ -441,6 +600,11 @@ static u8 smp_cmd_pairing_req(struct l2cap_conn *conn, struct sk_buff *skb)
 
 	smp_send_cmd(conn, SMP_CMD_PAIRING_RSP, sizeof(rsp), &rsp);
 
+	/* Request setup of TK */
+	ret = tk_request(conn, 0, auth, rsp.io_capability, req->io_capability);
+	if (ret)
+		return SMP_UNSPECIFIED;
+
 	return 0;
 }
 
@@ -449,11 +613,14 @@ static u8 smp_cmd_pairing_rsp(struct l2cap_conn *conn, struct sk_buff *skb)
 	struct smp_cmd_pairing *req, *rsp = (void *) skb->data;
 	struct smp_chan *smp = conn->smp_chan;
 	struct hci_dev *hdev = conn->hcon->hdev;
-	u8 key_size;
+	u8 key_size, auth = SMP_AUTH_NONE;
 	int ret;
 
 	BT_DBG("conn %p", conn);
 
+	if (!(conn->hcon->link_mode & HCI_LM_MASTER))
+		return SMP_CMD_NOTSUPP;
+
 	skb_pull(skb, sizeof(*rsp));
 
 	req = (void *) &smp->preq[1];
@@ -462,12 +629,6 @@ static u8 smp_cmd_pairing_rsp(struct l2cap_conn *conn, struct sk_buff *skb)
 	if (check_enc_key_size(conn, key_size))
 		return SMP_ENC_KEY_SIZE;
 
-	if (rsp->oob_flag)
-		return SMP_OOB_NOT_AVAIL;
-
-	/* Just works */
-	memset(smp->tk, 0, sizeof(smp->tk));
-
 	ret = smp_rand(smp->prnd);
 	if (ret)
 		return SMP_UNSPECIFIED;
@@ -475,6 +636,22 @@ static u8 smp_cmd_pairing_rsp(struct l2cap_conn *conn, struct sk_buff *skb)
 	smp->prsp[0] = SMP_CMD_PAIRING_RSP;
 	memcpy(&smp->prsp[1], rsp, sizeof(*rsp));
 
+	if ((req->auth_req & SMP_AUTH_BONDING) &&
+			(rsp->auth_req & SMP_AUTH_BONDING))
+		auth = SMP_AUTH_BONDING;
+
+	auth |= (req->auth_req | rsp->auth_req) & SMP_AUTH_MITM;
+
+	ret = tk_request(conn, 0, auth, rsp->io_capability, req->io_capability);
+	if (ret)
+		return SMP_UNSPECIFIED;
+
+	smp->smp_cfm_pending = 1;
+
+	/* Can't compose response until we have been confirmed */
+	if (!smp->smp_tk_valid)
+		return 0;
+
 	queue_work(hdev->workqueue, &smp->confirm);
 
 	return 0;
@@ -496,8 +673,10 @@ static u8 smp_cmd_pairing_confirm(struct l2cap_conn *conn, struct sk_buff *skb)
 		swap128(smp->prnd, random);
 		smp_send_cmd(conn, SMP_CMD_PAIRING_RANDOM, sizeof(random),
 								random);
-	} else {
+	} else if (smp->smp_tk_valid) {
 		queue_work(hdev->workqueue, &smp->confirm);
+	} else {
+		smp->smp_cfm_pending = 1;
 	}
 
 	return 0;
@@ -550,7 +729,7 @@ static u8 smp_cmd_security_req(struct l2cap_conn *conn, struct sk_buff *skb)
 
 	BT_DBG("conn %p", conn);
 
-	hcon->pending_sec_level = BT_SECURITY_MEDIUM;
+	hcon->pending_sec_level = authreq_to_seclevel(rp->auth_req);
 
 	if (smp_ltk_encrypt(conn))
 		return 0;
@@ -577,6 +756,7 @@ int smp_conn_security(struct l2cap_conn *conn, __u8 sec_level)
 {
 	struct hci_conn *hcon = conn->hcon;
 	struct smp_chan *smp = conn->smp_chan;
+	__u8 authreq;
 
 	BT_DBG("conn %p hcon %p level 0x%2.2x", conn, hcon, sec_level);
 
@@ -597,18 +777,22 @@ int smp_conn_security(struct l2cap_conn *conn, __u8 sec_level)
 		return 0;
 
 	smp = smp_chan_create(conn);
+	if (!smp)
+		return 1;
+
+	authreq = seclevel_to_authreq(sec_level);
 
 	if (hcon->link_mode & HCI_LM_MASTER) {
 		struct smp_cmd_pairing cp;
 
-		build_pairing_cmd(conn, &cp, NULL, SMP_AUTH_NONE);
+		build_pairing_cmd(conn, &cp, NULL, authreq);
 		smp->preq[0] = SMP_CMD_PAIRING_REQ;
 		memcpy(&smp->preq[1], &cp, sizeof(cp));
 
 		smp_send_cmd(conn, SMP_CMD_PAIRING_REQ, sizeof(cp), &cp);
 	} else {
 		struct smp_cmd_security_req cp;
-		cp.auth_req = SMP_AUTH_NONE;
+		cp.auth_req = authreq;
 		smp_send_cmd(conn, SMP_CMD_SECURITY_REQ, sizeof(cp), &cp);
 	}
 
-- 
1.7.7.2

-- 
Brian Gix
bgix@codeaurora.org
Employee of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum 

Re: [PATCH-v5 5/6] Bluetooth: Add MITM mechanism to LE-SMP

[Gustavo Padovan]

Hi Brian,

* Brian Gix <bgix@codeaurora.org> [2011-11-23 08:28:37 -0800]:

> To achive Man-In-The-Middle (MITM) level security with Low Energy,
> we have to enable User Passkey Comparison.  This commit modifies the
> hard-coded JUST-WORKS pairing mechanism to support query via the MGMT
> interface of Passkey comparison and User Confirmation.
> 
> Signed-off-by: Brian Gix <bgix@codeaurora.org>
> ---
>  include/net/bluetooth/hci_core.h |    1 +
>  include/net/bluetooth/smp.h      |    3 +
>  net/bluetooth/smp.c              |  228 ++++++++++++++++++++++++++++++++++----
>  3 files changed, 210 insertions(+), 22 deletions(-)
> 
> diff --git a/include/net/bluetooth/hci_core.h b/include/net/bluetooth/hci_core.h
> index e7b2e25..4aa417c 100644
> --- a/include/net/bluetooth/hci_core.h
> +++ b/include/net/bluetooth/hci_core.h
> @@ -312,6 +312,7 @@ struct hci_conn {
>  	struct hci_dev	*hdev;
>  	void		*l2cap_data;
>  	void		*sco_data;
> +	void		*smp_conn;
>  
>  	struct hci_conn	*link;
>  
> diff --git a/include/net/bluetooth/smp.h b/include/net/bluetooth/smp.h
> index 15b97d5..43b6c49 100644
> --- a/include/net/bluetooth/smp.h
> +++ b/include/net/bluetooth/smp.h
> @@ -124,6 +124,8 @@ struct smp_chan {
>  	u8		pcnf[16]; /* SMP Pairing Confirm */
>  	u8		tk[16]; /* SMP Temporary Key */
>  	u8		smp_key_size;
> +	u8		smp_tk_valid;
> +	u8		smp_cfm_pending;

Those two could be converted in a bitfield, you are using them as boolean.

>  	struct crypto_blkcipher	*tfm;
>  	struct work_struct confirm;
>  	struct work_struct random;
> @@ -134,6 +136,7 @@ struct smp_chan {
>  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);
> +int smp_user_confirm_reply(struct hci_conn *conn, u16 mgmt_op, __le32 passkey);
>  
>  void smp_chan_destroy(struct l2cap_conn *conn);
>  
> diff --git a/net/bluetooth/smp.c b/net/bluetooth/smp.c
> index 0b96737..e1df0a2 100644
> --- a/net/bluetooth/smp.c
> +++ b/net/bluetooth/smp.c
> @@ -23,6 +23,7 @@
>  #include <net/bluetooth/bluetooth.h>
>  #include <net/bluetooth/hci_core.h>
>  #include <net/bluetooth/l2cap.h>
> +#include <net/bluetooth/mgmt.h>
>  #include <net/bluetooth/smp.h>
>  #include <linux/crypto.h>
>  #include <linux/scatterlist.h>
> @@ -188,24 +189,46 @@ static void smp_send_cmd(struct l2cap_conn *conn, u8 code, u16 len, void *data)
>  					msecs_to_jiffies(SMP_TIMEOUT));
>  }
>  
> +static __u8 authreq_to_seclevel(__u8 authreq)
> +{
> +	if (authreq & SMP_AUTH_MITM)
> +		return BT_SECURITY_HIGH;
> +	else
> +		return BT_SECURITY_MEDIUM;
> +}
> +
> +static __u8 seclevel_to_authreq(__u8 sec_level)
> +{
> +	switch (sec_level) {
> +	case BT_SECURITY_HIGH:
> +		return SMP_AUTH_MITM | SMP_AUTH_BONDING;
> +	case BT_SECURITY_MEDIUM:
> +		return SMP_AUTH_BONDING;
> +	default:
> +		return SMP_AUTH_NONE;
> +	}
> +}
> +
>  static void build_pairing_cmd(struct l2cap_conn *conn,
>  				struct smp_cmd_pairing *req,
>  				struct smp_cmd_pairing *rsp,
>  				__u8 authreq)
>  {
> -	u8 dist_keys;
> +	u8 all_keys = 0;
> +	u8 dist_keys = 0;
>  
> -	dist_keys = 0;
>  	if (test_bit(HCI_PAIRABLE, &conn->hcon->hdev->flags)) {
>  		dist_keys = SMP_DIST_ENC_KEY;
>  		authreq |= SMP_AUTH_BONDING;
> +	} else {
> +		authreq &= ~SMP_AUTH_BONDING;
>  	}
>  
>  	if (rsp == NULL) {
>  		req->io_capability = conn->hcon->io_capability;
>  		req->oob_flag = SMP_OOB_NOT_PRESENT;
>  		req->max_key_size = SMP_MAX_ENC_KEY_SIZE;
> -		req->init_key_dist = dist_keys;
> +		req->init_key_dist = all_keys;
>  		req->resp_key_dist = dist_keys;
>  		req->auth_req = authreq;
>  		return;
> @@ -214,7 +237,7 @@ static void build_pairing_cmd(struct l2cap_conn *conn,
>  	rsp->io_capability = conn->hcon->io_capability;
>  	rsp->oob_flag = SMP_OOB_NOT_PRESENT;
>  	rsp->max_key_size = SMP_MAX_ENC_KEY_SIZE;
> -	rsp->init_key_dist = req->init_key_dist & dist_keys;
> +	rsp->init_key_dist = req->init_key_dist & all_keys;

all_keys is always zero. What's the purpose of create it?

	Gustavo

Re: [PATCH-v5 5/6] Bluetooth: Add MITM mechanism to LE-SMP

[Brian Gix]

On 12/1/2011 6:11 AM, Gustavo Padovan wrote:
> Hi Brian,

>> diff --git a/include/net/bluetooth/smp.h b/include/net/bluetooth/smp.h
>> index 15b97d5..43b6c49 100644
>> --- a/include/net/bluetooth/smp.h
>> +++ b/include/net/bluetooth/smp.h
>> @@ -124,6 +124,8 @@ struct smp_chan {
>>   	u8		pcnf[16]; /* SMP Pairing Confirm */
>>   	u8		tk[16]; /* SMP Temporary Key */
>>   	u8		smp_key_size;
>> +	u8		smp_tk_valid;
>> +	u8		smp_cfm_pending;
>
> Those two could be converted in a bitfield, you are using them as boolean.
>

Is there a mandate that bitfields must be manipulated/checked with the 
clear_bit/set_bit/test_bit prototypes?  Or can I just use a single u8 to 
represent both boolean values (as opposed to an unsigned long), and use 
standard &=, |= and & to set/clear/check?


-- 
Brian Gix
bgix@codeaurora.org
Employee of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum

Re: [PATCH-v5 5/6] Bluetooth: Add MITM mechanism to LE-SMP

[Gustavo Padovan]

Hi Brian,

* Brian Gix <bgix@codeaurora.org> [2011-12-01 10:35:30 -0800]:

> On 12/1/2011 6:11 AM, Gustavo Padovan wrote:
> >Hi Brian,
> 
> >>diff --git a/include/net/bluetooth/smp.h b/include/net/bluetooth/smp.h
> >>index 15b97d5..43b6c49 100644
> >>--- a/include/net/bluetooth/smp.h
> >>+++ b/include/net/bluetooth/smp.h
> >>@@ -124,6 +124,8 @@ struct smp_chan {
> >>  	u8		pcnf[16]; /* SMP Pairing Confirm */
> >>  	u8		tk[16]; /* SMP Temporary Key */
> >>  	u8		smp_key_size;
> >>+	u8		smp_tk_valid;
> >>+	u8		smp_cfm_pending;
> >
> >Those two could be converted in a bitfield, you are using them as boolean.
> >
> 
> Is there a mandate that bitfields must be manipulated/checked with
> the clear_bit/set_bit/test_bit prototypes?  Or can I just use a
> single u8 to represent both boolean values (as opposed to an
> unsigned long), and use standard &=, |= and & to set/clear/check?

Please use clear/set/test_bit, it is the right way.

	Gustavo

[PATCH-v5 6/6] Bluetooth: Add SMP to User Passkey and Confirm

[Brian Gix]

Low Energy pairing is performed through the SMP (Security Manager Protocol)
mechanism rather than HCI.

Signed-off-by: Brian Gix <bgix@codeaurora.org>
---
 net/bluetooth/mgmt.c |   10 +++++++++-
 1 files changed, 9 insertions(+), 1 deletions(-)

diff --git a/net/bluetooth/mgmt.c b/net/bluetooth/mgmt.c
index 7a23f21..4e05e24 100644
--- a/net/bluetooth/mgmt.c
+++ b/net/bluetooth/mgmt.c
@@ -29,6 +29,7 @@
 #include <net/bluetooth/bluetooth.h>
 #include <net/bluetooth/hci_core.h>
 #include <net/bluetooth/mgmt.h>
+#include <net/bluetooth/smp.h>
 
 #define MGMT_VERSION	0
 #define MGMT_REVISION	1
@@ -1606,8 +1607,15 @@ static int user_pairing_resp(struct sock *sk, u16 index, bdaddr_t *bdaddr,
 		}
 
 		/* Continue with pairing via SMP */
+		err = smp_user_confirm_reply(conn, mgmt_op, passkey);
+
+		if (!err)
+			err = cmd_status(sk, index, mgmt_op,
+							MGMT_STATUS_SUCCESS);
+		else
+			err = cmd_status(sk, index, mgmt_op,
+							MGMT_STATUS_FAILED);
 
-		err = cmd_status(sk, index, mgmt_op, MGMT_STATUS_SUCCESS);
 		goto done;
 	}
 
-- 
1.7.7.2

-- 
Brian Gix
bgix@codeaurora.org
Employee of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum