Bluetooth: Implementation of MGMT_OP_SET_BLOCKED_KEYS.

MGMT command is added to receive the list of blocked keys from
user-space.

The list is used to:
1) Block keys from being distributed by the device during
   the ke distribution phase of SMP.
2) Filter out any keys that were previously saved so
   they are no longer used.

Signed-off-by: Alain Michaud <alainm@chromium.org>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

1 files changed, 77 insertions, 8 deletions

diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
index 9e19d5a3aac8..f0298db26dc3 100644
--- a/net/bluetooth/hci_core.c
+++ b/net/bluetooth/hci_core.c
@@ -2311,6 +2311,33 @@ void hci_smp_irks_clear(struct hci_dev *hdev)
 	}
 }
 
+void hci_blocked_keys_clear(struct hci_dev *hdev)
+{
+	struct blocked_key *b;
+
+	list_for_each_entry_rcu(b, &hdev->blocked_keys, list) {
+		list_del_rcu(&b->list);
+		kfree_rcu(b, rcu);
+	}
+}
+
+bool hci_is_blocked_key(struct hci_dev *hdev, u8 type, u8 val[16])
+{
+	bool blocked = false;
+	struct blocked_key *b;
+
+	rcu_read_lock();
+	list_for_each_entry(b, &hdev->blocked_keys, list) {
+		if (b->type == type && !memcmp(b->val, val, sizeof(b->val))) {
+			blocked = true;
+			break;
+		}
+	}
+
+	rcu_read_unlock();
+	return blocked;
+}
+
 struct link_key *hci_find_link_key(struct hci_dev *hdev, bdaddr_t *bdaddr)
 {
 	struct link_key *k;
@@ -2319,6 +2346,16 @@ struct link_key *hci_find_link_key(struct hci_dev *hdev, bdaddr_t *bdaddr)
 	list_for_each_entry_rcu(k, &hdev->link_keys, list) {
 		if (bacmp(bdaddr, &k->bdaddr) == 0) {
 			rcu_read_unlock();
+
+			if (hci_is_blocked_key(hdev,
+					       HCI_BLOCKED_KEY_TYPE_LINKKEY,
+					       k->val)) {
+				bt_dev_warn_ratelimited(hdev,
+							"Link key blocked for %pMR",
+							&k->bdaddr);
+				return NULL;
+			}
+
 			return k;
 		}
 	}
@@ -2387,6 +2424,15 @@ struct smp_ltk *hci_find_ltk(struct hci_dev *hdev, bdaddr_t *bdaddr,
 
 		if (smp_ltk_is_sc(k) || ltk_role(k->type) == role) {
 			rcu_read_unlock();
+
+			if (hci_is_blocked_key(hdev, HCI_BLOCKED_KEY_TYPE_LTK,
+					       k->val)) {
+				bt_dev_warn_ratelimited(hdev,
+							"LTK blocked for %pMR",
+							&k->bdaddr);
+				return NULL;
+			}
+
 			return k;
 		}
 	}
@@ -2397,31 +2443,42 @@ struct smp_ltk *hci_find_ltk(struct hci_dev *hdev, bdaddr_t *bdaddr,
 
 struct smp_irk *hci_find_irk_by_rpa(struct hci_dev *hdev, bdaddr_t *rpa)
 {
+	struct smp_irk *irk_to_return = NULL;
 	struct smp_irk *irk;
 
 	rcu_read_lock();
 	list_for_each_entry_rcu(irk, &hdev->identity_resolving_keys, list) {
 		if (!bacmp(&irk->rpa, rpa)) {
-			rcu_read_unlock();
-			return irk;
+			irk_to_return = irk;
+			goto done;
 		}
 	}
 
 	list_for_each_entry_rcu(irk, &hdev->identity_resolving_keys, list) {
 		if (smp_irk_matches(hdev, irk->val, rpa)) {
 			bacpy(&irk->rpa, rpa);
-			rcu_read_unlock();
-			return irk;
+			irk_to_return = irk;
+			goto done;
 		}
 	}
+
+done:
+	if (irk_to_return && hci_is_blocked_key(hdev, HCI_BLOCKED_KEY_TYPE_IRK,
+						irk_to_return->val)) {
+		bt_dev_warn_ratelimited(hdev, "Identity key blocked for %pMR",
+					&irk_to_return->bdaddr);
+		irk_to_return = NULL;
+	}
+
 	rcu_read_unlock();
 
-	return NULL;
+	return irk_to_return;
 }
 
 struct smp_irk *hci_find_irk_by_addr(struct hci_dev *hdev, bdaddr_t *bdaddr,
 				     u8 addr_type)
 {
+	struct smp_irk *irk_to_return = NULL;
 	struct smp_irk *irk;
 
 	/* Identity Address must be public or static random */
@@ -2432,13 +2489,23 @@ struct smp_irk *hci_find_irk_by_addr(struct hci_dev *hdev, bdaddr_t *bdaddr,
 	list_for_each_entry_rcu(irk, &hdev->identity_resolving_keys, list) {
 		if (addr_type == irk->addr_type &&
 		    bacmp(bdaddr, &irk->bdaddr) == 0) {
-			rcu_read_unlock();
-			return irk;
+			irk_to_return = irk;
+			goto done;
 		}
 	}
+
+done:
+
+	if (irk_to_return && hci_is_blocked_key(hdev, HCI_BLOCKED_KEY_TYPE_IRK,
+						irk_to_return->val)) {
+		bt_dev_warn_ratelimited(hdev, "Identity key blocked for %pMR",
+					&irk_to_return->bdaddr);
+		irk_to_return = NULL;
+	}
+
 	rcu_read_unlock();
 
-	return NULL;
+	return irk_to_return;
 }
 
 struct link_key *hci_add_link_key(struct hci_dev *hdev, struct hci_conn *conn,
@@ -3244,6 +3311,7 @@ struct hci_dev *hci_alloc_dev(void)
 	INIT_LIST_HEAD(&hdev->pend_le_reports);
 	INIT_LIST_HEAD(&hdev->conn_hash.list);
 	INIT_LIST_HEAD(&hdev->adv_instances);
+	INIT_LIST_HEAD(&hdev->blocked_keys);
 
 	INIT_WORK(&hdev->rx_work, hci_rx_work);
 	INIT_WORK(&hdev->cmd_work, hci_cmd_work);
@@ -3443,6 +3511,7 @@ void hci_unregister_dev(struct hci_dev *hdev)
 	hci_bdaddr_list_clear(&hdev->le_resolv_list);
 	hci_conn_params_clear_all(hdev);
 	hci_discovery_filter_clear(hdev);
+	hci_blocked_keys_clear(hdev);
 	hci_dev_unlock(hdev);
 
 	hci_dev_put(hdev);