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, 76 insertions, 0 deletions

diff --git a/net/bluetooth/mgmt.c b/net/bluetooth/mgmt.c
index acb7c6d5643f..339c762eb6fd 100644
--- a/net/bluetooth/mgmt.c
+++ b/net/bluetooth/mgmt.c
@@ -106,6 +106,7 @@ static const u16 mgmt_commands[] = {
 	MGMT_OP_START_LIMITED_DISCOVERY,
 	MGMT_OP_READ_EXT_INFO,
 	MGMT_OP_SET_APPEARANCE,
+	MGMT_OP_SET_BLOCKED_KEYS,
 };
 
 static const u16 mgmt_events[] = {
@@ -2341,6 +2342,14 @@ static int load_link_keys(struct sock *sk, struct hci_dev *hdev, void *data,
 	for (i = 0; i < key_count; i++) {
 		struct mgmt_link_key_info *key = &cp->keys[i];
 
+		if (hci_is_blocked_key(hdev,
+				       HCI_BLOCKED_KEY_TYPE_LINKKEY,
+				       key->val)) {
+			bt_dev_warn(hdev, "Skipping blocked link key for %pMR",
+				    &key->addr.bdaddr);
+			continue;
+		}
+
 		/* Always ignore debug keys and require a new pairing if
 		 * the user wants to use them.
 		 */
@@ -3531,6 +3540,55 @@ unlock:
 	return err;
 }
 
+static int set_blocked_keys(struct sock *sk, struct hci_dev *hdev, void *data,
+			    u16 len)
+{
+	int err = MGMT_STATUS_SUCCESS;
+	struct mgmt_cp_set_blocked_keys *keys = data;
+	const u16 max_key_count = ((U16_MAX - sizeof(*keys)) /
+				   sizeof(struct mgmt_blocked_key_info));
+	u16 key_count, expected_len;
+	int i;
+
+	BT_DBG("request for %s", hdev->name);
+
+	key_count = __le16_to_cpu(keys->key_count);
+	if (key_count > max_key_count) {
+		bt_dev_err(hdev, "too big key_count value %u", key_count);
+		return mgmt_cmd_status(sk, hdev->id, MGMT_OP_SET_BLOCKED_KEYS,
+				       MGMT_STATUS_INVALID_PARAMS);
+	}
+
+	expected_len = struct_size(keys, keys, key_count);
+	if (expected_len != len) {
+		bt_dev_err(hdev, "expected %u bytes, got %u bytes",
+			   expected_len, len);
+		return mgmt_cmd_status(sk, hdev->id, MGMT_OP_SET_BLOCKED_KEYS,
+				       MGMT_STATUS_INVALID_PARAMS);
+	}
+
+	hci_dev_lock(hdev);
+
+	hci_blocked_keys_clear(hdev);
+
+	for (i = 0; i < keys->key_count; ++i) {
+		struct blocked_key *b = kzalloc(sizeof(*b), GFP_KERNEL);
+
+		if (!b) {
+			err = MGMT_STATUS_NO_RESOURCES;
+			break;
+		}
+
+		b->type = keys->keys[i].type;
+		memcpy(b->val, keys->keys[i].val, sizeof(b->val));
+		list_add_rcu(&b->list, &hdev->blocked_keys);
+	}
+	hci_dev_unlock(hdev);
+
+	return mgmt_cmd_complete(sk, hdev->id, MGMT_OP_SET_BLOCKED_KEYS,
+				err, NULL, 0);
+}
+
 static void read_local_oob_data_complete(struct hci_dev *hdev, u8 status,
 				         u16 opcode, struct sk_buff *skb)
 {
@@ -5051,6 +5109,14 @@ static int load_irks(struct sock *sk, struct hci_dev *hdev, void *cp_data,
 	for (i = 0; i < irk_count; i++) {
 		struct mgmt_irk_info *irk = &cp->irks[i];
 
+		if (hci_is_blocked_key(hdev,
+				       HCI_BLOCKED_KEY_TYPE_IRK,
+				       irk->val)) {
+			bt_dev_warn(hdev, "Skipping blocked IRK for %pMR",
+				    &irk->addr.bdaddr);
+			continue;
+		}
+
 		hci_add_irk(hdev, &irk->addr.bdaddr,
 			    le_addr_type(irk->addr.type), irk->val,
 			    BDADDR_ANY);
@@ -5134,6 +5200,14 @@ static int load_long_term_keys(struct sock *sk, struct hci_dev *hdev,
 		struct mgmt_ltk_info *key = &cp->keys[i];
 		u8 type, authenticated;
 
+		if (hci_is_blocked_key(hdev,
+				       HCI_BLOCKED_KEY_TYPE_LTK,
+				       key->val)) {
+			bt_dev_warn(hdev, "Skipping blocked LTK for %pMR",
+				    &key->addr.bdaddr);
+			continue;
+		}
+
 		switch (key->type) {
 		case MGMT_LTK_UNAUTHENTICATED:
 			authenticated = 0x00;
@@ -6914,6 +6988,8 @@ static const struct hci_mgmt_handler mgmt_handlers[] = {
 	{ set_appearance,	   MGMT_SET_APPEARANCE_SIZE },
 	{ get_phy_configuration,   MGMT_GET_PHY_CONFIGURATION_SIZE },
 	{ set_phy_configuration,   MGMT_SET_PHY_CONFIGURATION_SIZE },
+	{ set_blocked_keys,	   MGMT_OP_SET_BLOCKED_KEYS_SIZE,
+						HCI_MGMT_VAR_LEN },
 };
 
 void mgmt_index_added(struct hci_dev *hdev)