Re: [PATCH 4/8] Bluetooth: Use the updated key structures for handling LTKs

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Hi Vinicius,

On 1/13/2012 11:39 AM, Vinicius Costa Gomes wrote:
This updates all the users of the older way, that was using the
link_keys list to store the SMP keys, to use the new way.

This includes defining new types for the keys, we have a type for each
combination of STK/LTK and Master/Slave.

Signed-off-by: Vinicius Costa Gomes<vinicius.gomes@xxxxxxxxxxxxx>
---
  include/net/bluetooth/hci_core.h |   11 +++--
  net/bluetooth/hci_core.c         |   79 ++++++++++++++++++--------------------
  net/bluetooth/hci_event.c        |    9 +++-
  net/bluetooth/smp.c              |   38 +++++++++++-------
  4 files changed, 73 insertions(+), 64 deletions(-)

diff --git a/include/net/bluetooth/hci_core.h b/include/net/bluetooth/hci_core.h
index 9d77a66..7ce25ad 100644
--- a/include/net/bluetooth/hci_core.h
+++ b/include/net/bluetooth/hci_core.h
@@ -651,12 +651,13 @@ int hci_link_keys_clear(struct hci_dev *hdev);
  struct link_key *hci_find_link_key(struct hci_dev *hdev, bdaddr_t *bdaddr);
  int hci_add_link_key(struct hci_dev *hdev, struct hci_conn *conn, int new_key,
  			bdaddr_t *bdaddr, u8 *val, u8 type, u8 pin_len);
-struct link_key *hci_find_ltk(struct hci_dev *hdev, __le16 ediv, u8 rand[8]);
-struct link_key *hci_find_link_key_type(struct hci_dev *hdev,
-					bdaddr_t *bdaddr, u8 type);
-int hci_add_ltk(struct hci_dev *hdev, int new_key, bdaddr_t *bdaddr,
-			u8 key_size, __le16 ediv, u8 rand[8], u8 ltk[16]);
+struct smp_ltk *hci_find_ltk(struct hci_dev *hdev, __le16 ediv, u8 rand[8]);
+int hci_add_ltk(struct hci_dev *hdev, bdaddr_t *bdaddr, u8 addr_type, u8 type,
+				int new_key, u8 authenticated, 	u8 tk[16],
+				u8 enc_size, u16 ediv, u8 rand[8]);
  int hci_remove_link_key(struct hci_dev *hdev, bdaddr_t *bdaddr);
+struct smp_ltk *hci_find_ltk_addr(struct hci_dev *hdev, bdaddr_t *bdaddr,
+								u8 addr_type);
  int hci_smp_ltks_clear(struct hci_dev *hdev);

  int hci_remote_oob_data_clear(struct hci_dev *hdev);
diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
index 3b5902d..5f41e74 100644
--- a/net/bluetooth/hci_core.c
+++ b/net/bluetooth/hci_core.c
@@ -1222,41 +1222,40 @@ static int hci_persistent_key(struct hci_dev *hdev, struct hci_conn *conn,
  	return 0;
  }

-struct link_key *hci_find_ltk(struct hci_dev *hdev, __le16 ediv, u8 rand[8])
+/* If the returned key is a STK it should be free'd by the caller */
+struct smp_ltk *hci_find_ltk(struct hci_dev *hdev, __le16 ediv, u8 rand[8])
  {
-	struct link_key *k;
-
-	list_for_each_entry(k,&hdev->link_keys, list) {
-		struct key_master_id *id;
+	struct smp_ltk *k, *tmp;

-		if (k->type != HCI_LK_SMP_LTK)
+	list_for_each_entry_safe(k, tmp,&hdev->ltks, list) {
+		if (k->ediv != ediv ||
+				memcmp(rand, k->rand, sizeof(k->rand)))
  			continue;

-		if (k->dlen != sizeof(*id))
-			continue;
+		/* The STK should only be used once, no need to keep it */
+		if (k->type&  HCI_SMP_STK)
+			list_del(&k->list);

Is HCI_SMP_STK a mask?  Shouldn't this be an equality test?


-		id = (void *)&k->data;
-		if (id->ediv == ediv&&
-				(memcmp(rand, id->rand, sizeof(id->rand)) == 0))
-			return k;
+		return k;
  	}

  	return NULL;
  }
  EXPORT_SYMBOL(hci_find_ltk);

-struct link_key *hci_find_link_key_type(struct hci_dev *hdev,
-					bdaddr_t *bdaddr, u8 type)
+struct smp_ltk *hci_find_ltk_addr(struct hci_dev *hdev, bdaddr_t *bdaddr,
+								u8 addr_type)
  {
-	struct link_key *k;
+	struct smp_ltk *k;

-	list_for_each_entry(k,&hdev->link_keys, list)
-		if (k->type == type&&  bacmp(bdaddr,&k->bdaddr) == 0)
+	list_for_each_entry(k,&hdev->ltks, list)
+		if (addr_type == k->bdaddr_type&&
+					bacmp(bdaddr,&k->bdaddr) == 0)
  			return k;

  	return NULL;
  }
-EXPORT_SYMBOL(hci_find_link_key_type);
+EXPORT_SYMBOL(hci_find_ltk_addr);

  int hci_add_link_key(struct hci_dev *hdev, struct hci_conn *conn, int new_key,
  				bdaddr_t *bdaddr, u8 *val, u8 type, u8 pin_len)
@@ -1313,40 +1312,36 @@ int hci_add_link_key(struct hci_dev *hdev, struct hci_conn *conn, int new_key,
  	return 0;
  }

-int hci_add_ltk(struct hci_dev *hdev, int new_key, bdaddr_t *bdaddr,
-			u8 key_size, __le16 ediv, u8 rand[8], u8 ltk[16])
+int hci_add_ltk(struct hci_dev *hdev, bdaddr_t *bdaddr, u8 addr_type, u8 type,
+				int new_key, u8 authenticated, 	u8 tk[16],
+				u8 enc_size, u16 ediv, u8 rand[8])
  {
-	struct link_key *key, *old_key;
-	struct key_master_id *id;
-	u8 old_key_type;
+	struct smp_ltk *key, *old_key;

-	BT_DBG("%s addr %s", hdev->name, batostr(bdaddr));
+	if (!(type&  HCI_SMP_STK)&&  !(type&  HCI_SMP_LTK))
+		return 0;

And here.


-	old_key = hci_find_link_key_type(hdev, bdaddr, HCI_LK_SMP_LTK);
-	if (old_key) {
+	old_key = hci_find_ltk_addr(hdev, bdaddr, addr_type);
+	if (old_key)
  		key = old_key;
-		old_key_type = old_key->type;
-	} else {
-		key = kzalloc(sizeof(*key) + sizeof(*id), GFP_ATOMIC);
+	else {
+		key = kzalloc(sizeof(*key), GFP_ATOMIC);
  		if (!key)
  			return -ENOMEM;

Looks like some whitespace issues.

-		list_add(&key->list,&hdev->link_keys);
-		old_key_type = 0xff;
+		list_add(&key->list,&hdev->ltks);
  	}

-	key->dlen = sizeof(*id);
-
  	bacpy(&key->bdaddr, bdaddr);
-	memcpy(key->val, ltk, sizeof(key->val));
-	key->type = HCI_LK_SMP_LTK;
-	key->pin_len = key_size;
-
-	id = (void *)&key->data;
-	id->ediv = ediv;
-	memcpy(id->rand, rand, sizeof(id->rand));
+	key->bdaddr_type = addr_type;
+	memcpy(key->val, tk, sizeof(key->val));
+	key->authenticated = authenticated;
+	key->ediv = ediv;
+	key->enc_size = enc_size;
+	key->type = type;
+	memcpy(key->rand, rand, sizeof(key->rand));

-	if (new_key)
-		mgmt_new_link_key(hdev, key, old_key_type);
+	if (!new_key)
+		return 0;

  	return 0;
  }
diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
index 94a9ca2..750fc0c 100644
--- a/net/bluetooth/hci_event.c
+++ b/net/bluetooth/hci_event.c
@@ -3227,7 +3227,7 @@ static inline void hci_le_ltk_request_evt(struct hci_dev *hdev,
  	struct hci_cp_le_ltk_reply cp;
  	struct hci_cp_le_ltk_neg_reply neg;
  	struct hci_conn *conn;
-	struct link_key *ltk;
+	struct smp_ltk *ltk;

  	BT_DBG("%s handle %d", hdev->name, cpu_to_le16(ev->handle));

@@ -3243,10 +3243,15 @@ static inline void hci_le_ltk_request_evt(struct hci_dev *hdev,

  	memcpy(cp.ltk, ltk->val, sizeof(ltk->val));
  	cp.handle = cpu_to_le16(conn->handle);
-	conn->pin_length = ltk->pin_len;
+
+	if (ltk->authenticated)
+		conn->sec_level = BT_SECURITY_HIGH;

  	hci_send_cmd(hdev, HCI_OP_LE_LTK_REPLY, sizeof(cp),&cp);

+	if (ltk->type&  HCI_SMP_STK)
+		kfree(ltk);
+
  	hci_dev_unlock(hdev);

  	return;
diff --git a/net/bluetooth/smp.c b/net/bluetooth/smp.c
index b7f2fd1..7bc82e4 100644
--- a/net/bluetooth/smp.c
+++ b/net/bluetooth/smp.c
@@ -472,8 +472,9 @@ static void random_work(struct work_struct *work)
  		memset(stk + smp->enc_key_size, 0,
  				SMP_MAX_ENC_KEY_SIZE - smp->enc_key_size);

-		hci_add_ltk(hcon->hdev, 0, conn->dst, smp->enc_key_size,
-							ediv, rand, stk);
+		hci_add_ltk(hcon->hdev, conn->dst, hcon->dst_type,
+						HCI_SMP_STK_SLAVE, 0, 0, stk,
+						smp->enc_key_size, ediv, rand);
  	}

  	return;
@@ -698,12 +699,10 @@ static u8 smp_cmd_pairing_random(struct l2cap_conn *conn, struct sk_buff *skb)

  static u8 smp_ltk_encrypt(struct l2cap_conn *conn)
  {
-	struct link_key *key;
-	struct key_master_id *master;
+	struct smp_ltk *key;
  	struct hci_conn *hcon = conn->hcon;

-	key = hci_find_link_key_type(hcon->hdev, conn->dst,
-						HCI_LK_SMP_LTK);
+	key = hci_find_ltk_addr(hcon->hdev, conn->dst, hcon->dst_type);
  	if (!key)
  		return 0;

@@ -711,10 +710,8 @@ static u8 smp_ltk_encrypt(struct l2cap_conn *conn)
  					&hcon->pend))
  		return 1;

-	master = (void *) key->data;
-	hci_le_start_enc(hcon, master->ediv, master->rand,
-						key->val);
-	hcon->enc_key_size = key->pin_len;
+	hci_le_start_enc(hcon, key->ediv, key->rand, key->val);
+	hcon->enc_key_size = key->enc_size;

  	return 1;

@@ -817,13 +814,19 @@ static int smp_cmd_master_ident(struct l2cap_conn *conn, struct sk_buff *skb)
  {
  	struct smp_cmd_master_ident *rp = (void *) skb->data;
  	struct smp_chan *smp = conn->smp_chan;
+	struct hci_dev *hdev = conn->hcon->hdev;
+	struct hci_conn *hcon = conn->hcon;
+	u8 authenticated;

  	skb_pull(skb, sizeof(*rp));

-	hci_add_ltk(conn->hcon->hdev, 1, conn->dst, smp->enc_key_size,
-						rp->ediv, rp->rand, smp->tk);
-
+	hci_dev_lock(hdev);
+	authenticated = (conn->hcon->sec_level == BT_SECURITY_HIGH);
+	hci_add_ltk(conn->hcon->hdev, conn->dst, hcon->dst_type,
+					HCI_SMP_LTK, 1, authenticated, smp->tk,
+					smp->enc_key_size, rp->ediv, rp->rand);
  	smp_distribute_keys(conn, 1);
+	hci_dev_unlock(hdev);

  	return 0;
  }
@@ -933,6 +936,8 @@ int smp_distribute_keys(struct l2cap_conn *conn, __u8 force)
  	if (*keydist&  SMP_DIST_ENC_KEY) {
  		struct smp_cmd_encrypt_info enc;
  		struct smp_cmd_master_ident ident;
+		struct hci_conn *hcon = conn->hcon;
+		u8 authenticated;
  		__le16 ediv;

  		get_random_bytes(enc.ltk, sizeof(enc.ltk));
@@ -941,8 +946,11 @@ int smp_distribute_keys(struct l2cap_conn *conn, __u8 force)

  		smp_send_cmd(conn, SMP_CMD_ENCRYPT_INFO, sizeof(enc),&enc);

-		hci_add_ltk(conn->hcon->hdev, 1, conn->dst, smp->enc_key_size,
-						ediv, ident.rand, enc.ltk);
+		authenticated = hcon->sec_level == BT_SECURITY_HIGH;
+		hci_add_ltk(conn->hcon->hdev, conn->dst, hcon->dst_type,
+					HCI_SMP_LTK_SLAVE, 1, authenticated,
+					enc.ltk, smp->enc_key_size,
+					ediv, ident.rand);

  		ident.ediv = cpu_to_le16(ediv);



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