[bluetooth-next v5 0/2] SMP Just Works implementation

[bluetooth-next v5 0/2] SMP Just Works implementation

[Vinicius Costa Gomes]

Hi Gustavo,

These are the last two patches (15/16 and 16/16) that needed a
rebase on top of your latest tree.

--
Cheers,


Vinicius Costa Gomes (2):
  Bluetooth: Add support for SMP timeout
  Bluetooth: Add key size checks for SMP

 include/net/bluetooth/l2cap.h |    3 ++
 include/net/bluetooth/smp.h   |    3 ++
 net/bluetooth/l2cap_core.c    |   74 ++++++++++++++++++++++++----------------
 net/bluetooth/smp.c           |   68 ++++++++++++++++++++++++++++++-------
 4 files changed, 105 insertions(+), 43 deletions(-)

--
1.7.5.4

[bluetooth-next v5 1/2] Bluetooth: Add support for SMP timeout

[Vinicius Costa Gomes]

This patch adds support for disconnecting the link when SMP procedure
takes more than 30 seconds.

SMP begins when either the Pairing Request command is sent or the
Pairing Response is received, and it ends when the link is encrypted
(or terminated). Vol 3, Part H Section 3.4.

Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@openbossa.org>
---
 include/net/bluetooth/l2cap.h |    2 +
 net/bluetooth/l2cap_core.c    |   74 ++++++++++++++++++++++++----------------
 net/bluetooth/smp.c           |   14 ++++++++
 3 files changed, 60 insertions(+), 30 deletions(-)

diff --git a/include/net/bluetooth/l2cap.h b/include/net/bluetooth/l2cap.h
index 01c993b..157419a 100644
--- a/include/net/bluetooth/l2cap.h
+++ b/include/net/bluetooth/l2cap.h
@@ -401,6 +401,8 @@ struct l2cap_conn {
 	__u8		pcnf[16]; /* SMP Pairing Confirm */
 	__u8		tk[16]; /* SMP Temporary Key */
 
+	struct timer_list security_timer;
+
 	struct list_head chan_l;
 	rwlock_t	chan_lock;
 };
diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
index 584a423..bbbae2e 100644
--- a/net/bluetooth/l2cap_core.c
+++ b/net/bluetooth/l2cap_core.c
@@ -970,6 +970,45 @@ static void l2cap_info_timeout(unsigned long arg)
 	l2cap_conn_start(conn);
 }
 
+static void l2cap_conn_del(struct hci_conn *hcon, int err)
+{
+	struct l2cap_conn *conn = hcon->l2cap_data;
+	struct l2cap_chan *chan, *l;
+	struct sock *sk;
+
+	if (!conn)
+		return;
+
+	BT_DBG("hcon %p conn %p, err %d", hcon, conn, err);
+
+	kfree_skb(conn->rx_skb);
+
+	/* Kill channels */
+	list_for_each_entry_safe(chan, l, &conn->chan_l, list) {
+		sk = chan->sk;
+		bh_lock_sock(sk);
+		l2cap_chan_del(chan, err);
+		bh_unlock_sock(sk);
+		chan->ops->close(chan->data);
+	}
+
+	if (conn->info_state & L2CAP_INFO_FEAT_MASK_REQ_SENT)
+		del_timer_sync(&conn->info_timer);
+
+	if (test_bit(HCI_CONN_ENCRYPT_PEND, &hcon->pend))
+		del_timer(&conn->security_timer);
+
+	hcon->l2cap_data = NULL;
+	kfree(conn);
+}
+
+static void security_timeout(unsigned long arg)
+{
+	struct l2cap_conn *conn = (void *) arg;
+
+	l2cap_conn_del(conn->hcon, ETIMEDOUT);
+}
+
 static struct l2cap_conn *l2cap_conn_add(struct hci_conn *hcon, u8 status)
 {
 	struct l2cap_conn *conn = hcon->l2cap_data;
@@ -1001,7 +1040,10 @@ static struct l2cap_conn *l2cap_conn_add(struct hci_conn *hcon, u8 status)
 
 	INIT_LIST_HEAD(&conn->chan_l);
 
-	if (hcon->type != LE_LINK)
+	if (hcon->type == LE_LINK)
+		setup_timer(&conn->security_timer, security_timeout,
+						(unsigned long) conn);
+	else
 		setup_timer(&conn->info_timer, l2cap_info_timeout,
 						(unsigned long) conn);
 
@@ -1010,35 +1052,6 @@ static struct l2cap_conn *l2cap_conn_add(struct hci_conn *hcon, u8 status)
 	return conn;
 }
 
-static void l2cap_conn_del(struct hci_conn *hcon, int err)
-{
-	struct l2cap_conn *conn = hcon->l2cap_data;
-	struct l2cap_chan *chan, *l;
-	struct sock *sk;
-
-	if (!conn)
-		return;
-
-	BT_DBG("hcon %p conn %p, err %d", hcon, conn, err);
-
-	kfree_skb(conn->rx_skb);
-
-	/* Kill channels */
-	list_for_each_entry_safe(chan, l, &conn->chan_l, list) {
-		sk = chan->sk;
-		bh_lock_sock(sk);
-		l2cap_chan_del(chan, err);
-		bh_unlock_sock(sk);
-		chan->ops->close(chan->data);
-	}
-
-	if (conn->info_state & L2CAP_INFO_FEAT_MASK_REQ_SENT)
-		del_timer_sync(&conn->info_timer);
-
-	hcon->l2cap_data = NULL;
-	kfree(conn);
-}
-
 static inline void l2cap_chan_add(struct l2cap_conn *conn, struct l2cap_chan *chan)
 {
 	write_lock_bh(&conn->chan_lock);
@@ -4182,6 +4195,7 @@ static int l2cap_security_cfm(struct hci_conn *hcon, u8 status, u8 encrypt)
 		if (chan->scid == L2CAP_CID_LE_DATA) {
 			if (!status && encrypt) {
 				chan->sec_level = hcon->sec_level;
+				del_timer(&conn->security_timer);
 				l2cap_chan_ready(sk);
 			}
 
diff --git a/net/bluetooth/smp.c b/net/bluetooth/smp.c
index dfd6891..3988678 100644
--- a/net/bluetooth/smp.c
+++ b/net/bluetooth/smp.c
@@ -27,6 +27,8 @@
 #include <linux/crypto.h>
 #include <crypto/b128ops.h>
 
+#define SMP_TIMEOUT 30000 /* 30 seconds */
+
 static inline void swap128(u8 src[16], u8 dst[16])
 {
 	int i;
@@ -228,6 +230,9 @@ static u8 smp_cmd_pairing_req(struct l2cap_conn *conn, struct sk_buff *skb)
 
 	smp_send_cmd(conn, SMP_CMD_PAIRING_RSP, sizeof(*rp), rp);
 
+	mod_timer(&conn->security_timer, jiffies +
+					msecs_to_jiffies(SMP_TIMEOUT));
+
 	return 0;
 }
 
@@ -303,6 +308,9 @@ static u8 smp_cmd_pairing_confirm(struct l2cap_conn *conn, struct sk_buff *skb)
 		smp_send_cmd(conn, SMP_CMD_PAIRING_CONFIRM, sizeof(cp), &cp);
 	}
 
+	mod_timer(&conn->security_timer, jiffies +
+					msecs_to_jiffies(SMP_TIMEOUT));
+
 	return 0;
 }
 
@@ -382,6 +390,9 @@ static u8 smp_cmd_security_req(struct l2cap_conn *conn, struct sk_buff *skb)
 
 	smp_send_cmd(conn, SMP_CMD_PAIRING_REQ, sizeof(cp), &cp);
 
+	mod_timer(&conn->security_timer, jiffies +
+					msecs_to_jiffies(SMP_TIMEOUT));
+
 	set_bit(HCI_CONN_ENCRYPT_PEND, &hcon->pend);
 
 	return 0;
@@ -415,6 +426,9 @@ int smp_conn_security(struct l2cap_conn *conn, __u8 sec_level)
 		conn->preq[0] = SMP_CMD_PAIRING_REQ;
 		memcpy(&conn->preq[1], &cp, sizeof(cp));
 
+		mod_timer(&conn->security_timer, jiffies +
+					msecs_to_jiffies(SMP_TIMEOUT));
+
 		smp_send_cmd(conn, SMP_CMD_PAIRING_REQ, sizeof(cp), &cp);
 	} else {
 		struct smp_cmd_security_req cp;
-- 
1.7.5.4

[bluetooth-next v5 2/2] Bluetooth: Add key size checks for SMP

[Vinicius Costa Gomes]

This patch implements a check in smp cmd pairing request and pairing
response to verify if encryption key maximum size is compatible in both
slave and master when SMP Pairing is requested. Keys are also masked to
the correct negotiated size.

Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@openbossa.org>
Signed-off-by: Anderson Briglia <anderson.briglia@openbossa.org>
---
 include/net/bluetooth/l2cap.h |    1 +
 include/net/bluetooth/smp.h   |    3 ++
 net/bluetooth/smp.c           |   54 +++++++++++++++++++++++++++++++----------
 3 files changed, 45 insertions(+), 13 deletions(-)

diff --git a/include/net/bluetooth/l2cap.h b/include/net/bluetooth/l2cap.h
index 157419a..bf1c7f6 100644
--- a/include/net/bluetooth/l2cap.h
+++ b/include/net/bluetooth/l2cap.h
@@ -400,6 +400,7 @@ struct l2cap_conn {
 	__u8		prnd[16]; /* SMP Pairing Random */
 	__u8		pcnf[16]; /* SMP Pairing Confirm */
 	__u8		tk[16]; /* SMP Temporary Key */
+	__u8		smp_key_size;
 
 	struct timer_list security_timer;
 
diff --git a/include/net/bluetooth/smp.h b/include/net/bluetooth/smp.h
index 111853a..4fb7d19 100644
--- a/include/net/bluetooth/smp.h
+++ b/include/net/bluetooth/smp.h
@@ -112,6 +112,9 @@ struct smp_cmd_security_req {
 #define SMP_UNSPECIFIED		0x08
 #define SMP_REPEATED_ATTEMPTS		0x09
 
+#define SMP_MIN_ENC_KEY_SIZE		7
+#define SMP_MAX_ENC_KEY_SIZE		16
+
 /* 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);
diff --git a/net/bluetooth/smp.c b/net/bluetooth/smp.c
index 3988678..52e9ec2 100644
--- a/net/bluetooth/smp.c
+++ b/net/bluetooth/smp.c
@@ -200,35 +200,51 @@ 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 = 16;
+	cmd->max_key_size = SMP_MAX_ENC_KEY_SIZE;
 	cmd->init_key_dist = 0x00;
 	cmd->resp_key_dist = 0x00;
 	cmd->auth_req = authreq;
 }
 
+static u8 check_enc_key_size(struct l2cap_conn *conn, __u8 max_key_size)
+{
+	if ((max_key_size > SMP_MAX_ENC_KEY_SIZE) ||
+			(max_key_size < SMP_MIN_ENC_KEY_SIZE))
+		return SMP_ENC_KEY_SIZE;
+
+	conn->smp_key_size = max_key_size;
+
+	return 0;
+}
+
 static u8 smp_cmd_pairing_req(struct l2cap_conn *conn, struct sk_buff *skb)
 {
-	struct smp_cmd_pairing *rp = (void *) skb->data;
+	struct smp_cmd_pairing rsp, *req = (void *) skb->data;
+	u8 key_size;
 
 	BT_DBG("conn %p", conn);
 
 	conn->preq[0] = SMP_CMD_PAIRING_REQ;
-	memcpy(&conn->preq[1], rp, sizeof(*rp));
-	skb_pull(skb, sizeof(*rp));
+	memcpy(&conn->preq[1], req, sizeof(*req));
+	skb_pull(skb, sizeof(*req));
 
-	if (rp->oob_flag)
+	if (req->oob_flag)
 		return SMP_OOB_NOT_AVAIL;
 
 	/* We didn't start the pairing, so no requirements */
-	build_pairing_cmd(conn, rp, SMP_AUTH_NONE);
+	build_pairing_cmd(conn, &rsp, SMP_AUTH_NONE);
+
+	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(conn->tk, 0, sizeof(conn->tk));
 
 	conn->prsp[0] = SMP_CMD_PAIRING_RSP;
-	memcpy(&conn->prsp[1], rp, sizeof(*rp));
+	memcpy(&conn->prsp[1], &rsp, sizeof(rsp));
 
-	smp_send_cmd(conn, SMP_CMD_PAIRING_RSP, sizeof(*rp), rp);
+	smp_send_cmd(conn, SMP_CMD_PAIRING_RSP, sizeof(rsp), &rsp);
 
 	mod_timer(&conn->security_timer, jiffies +
 					msecs_to_jiffies(SMP_TIMEOUT));
@@ -238,24 +254,30 @@ static u8 smp_cmd_pairing_req(struct l2cap_conn *conn, struct sk_buff *skb)
 
 static u8 smp_cmd_pairing_rsp(struct l2cap_conn *conn, struct sk_buff *skb)
 {
-	struct smp_cmd_pairing *rp = (void *) skb->data;
+	struct smp_cmd_pairing *req, *rsp = (void *) skb->data;
 	struct smp_cmd_pairing_confirm cp;
 	struct crypto_blkcipher *tfm = conn->hcon->hdev->tfm;
 	int ret;
-	u8 res[16];
+	u8 res[16], key_size;
 
 	BT_DBG("conn %p", conn);
 
-	skb_pull(skb, sizeof(*rp));
+	skb_pull(skb, sizeof(*rsp));
+
+	req = (void *) &conn->preq[1];
 
-	if (rp->oob_flag)
+	key_size = min(req->max_key_size, rsp->max_key_size);
+	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(conn->tk, 0, sizeof(conn->tk));
 
 	conn->prsp[0] = SMP_CMD_PAIRING_RSP;
-	memcpy(&conn->prsp[1], rp, sizeof(*rp));
+	memcpy(&conn->prsp[1], rsp, sizeof(*rsp));
 
 	ret = smp_rand(conn->prnd);
 	if (ret)
@@ -353,6 +375,9 @@ static u8 smp_cmd_pairing_random(struct l2cap_conn *conn, struct sk_buff *skb)
 		smp_s1(tfm, conn->tk, random, conn->prnd, key);
 		swap128(key, hcon->ltk);
 
+		memset(hcon->ltk + conn->smp_key_size, 0,
+				SMP_MAX_ENC_KEY_SIZE - conn->smp_key_size);
+
 		memset(rand, 0, sizeof(rand));
 		ediv = 0;
 		hci_le_start_enc(hcon, ediv, rand, hcon->ltk);
@@ -364,6 +389,9 @@ static u8 smp_cmd_pairing_random(struct l2cap_conn *conn, struct sk_buff *skb)
 
 		smp_s1(tfm, conn->tk, conn->prnd, random, key);
 		swap128(key, hcon->ltk);
+
+		memset(hcon->ltk + conn->smp_key_size, 0,
+				SMP_MAX_ENC_KEY_SIZE - conn->smp_key_size);
 	}
 
 	return 0;
-- 
1.7.5.4

Re: [bluetooth-next v5 0/2] SMP Just Works implementation

[Gustavo F. Padovan]

* Vinicius Costa Gomes <vinicius.gomes@openbossa.org> [2011-06-14 13:37:40 -0300]:

> Hi Gustavo,
> 
> These are the last two patches (15/16 and 16/16) that needed a
> rebase on top of your latest tree.
> 
> --
> Cheers,
> 
> 
> Vinicius Costa Gomes (2):
>   Bluetooth: Add support for SMP timeout
>   Bluetooth: Add key size checks for SMP
> 
>  include/net/bluetooth/l2cap.h |    3 ++
>  include/net/bluetooth/smp.h   |    3 ++
>  net/bluetooth/l2cap_core.c    |   74 ++++++++++++++++++++++++----------------
>  net/bluetooth/smp.c           |   68 ++++++++++++++++++++++++++++++-------
>  4 files changed, 105 insertions(+), 43 deletions(-)

Both patches applied. Thanks.

	Gustavo