tipc: add support for AEAD key setting via netlink

This commit adds two netlink commands to TIPC in order for user to be
able to set or remove AEAD keys:
- TIPC_NL_KEY_SET
- TIPC_NL_KEY_FLUSH

When the 'KEY_SET' is given along with the key data, the key will be
initiated and attached to TIPC crypto. On the other hand, the
'KEY_FLUSH' command will remove all existing keys if any.

Acked-by: Ying Xue <[e-mail]>
Acked-by: Jon Maloy <[e-mail]>
Signed-off-by: Tuong Lien <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

include/uapi/linux/tipc_netlink.h

···
 	TIPC_NL_PEER_REMOVE,
 	TIPC_NL_BEARER_ADD,
 	TIPC_NL_UDP_GET_REMOTEIP,
+	TIPC_NL_KEY_SET,
+	TIPC_NL_KEY_FLUSH,
 
 	__TIPC_NL_CMD_MAX,
 	TIPC_NL_CMD_MAX = __TIPC_NL_CMD_MAX - 1
···
 	TIPC_NLA_NODE_UNSPEC,
 	TIPC_NLA_NODE_ADDR,		/* u32 */
 	TIPC_NLA_NODE_UP,		/* flag */
+	TIPC_NLA_NODE_ID,		/* data */
+	TIPC_NLA_NODE_KEY,		/* data */
 
 	__TIPC_NLA_NODE_MAX,
 	TIPC_NLA_NODE_MAX = __TIPC_NLA_NODE_MAX - 1

net/tipc/netlink.c

···
 const struct nla_policy tipc_nl_node_policy[TIPC_NLA_NODE_MAX + 1] = {
 	[TIPC_NLA_NODE_UNSPEC]		= { .type = NLA_UNSPEC },
 	[TIPC_NLA_NODE_ADDR]		= { .type = NLA_U32 },
-	[TIPC_NLA_NODE_UP]		= { .type = NLA_FLAG }
+	[TIPC_NLA_NODE_UP]		= { .type = NLA_FLAG },
+	[TIPC_NLA_NODE_ID]		= { .type = NLA_BINARY,
+					    .len = TIPC_NODEID_LEN},
+	[TIPC_NLA_NODE_KEY]		= { .type = NLA_BINARY,
+					    .len = TIPC_AEAD_KEY_SIZE_MAX},
 };
 
 /* Properties valid for media, bearer and link */
···
 		.validate = GENL_DONT_VALIDATE_STRICT |
 			    GENL_DONT_VALIDATE_DUMP_STRICT,
 		.dumpit	= tipc_udp_nl_dump_remoteip,
+	},
+#endif
+#ifdef CONFIG_TIPC_CRYPTO
+	{
+		.cmd	= TIPC_NL_KEY_SET,
+		.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
+		.doit	= tipc_nl_node_set_key,
+	},
+	{
+		.cmd	= TIPC_NL_KEY_FLUSH,
+		.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
+		.doit	= tipc_nl_node_flush_key,
 	},
 #endif
 };

net/tipc/node.c

···
 	return skb->len;
 }
 
+#ifdef CONFIG_TIPC_CRYPTO
+static int tipc_nl_retrieve_key(struct nlattr **attrs,
+				struct tipc_aead_key **key)
+{
+	struct nlattr *attr = attrs[TIPC_NLA_NODE_KEY];
+
+	if (!attr)
+		return -ENODATA;
+
+	*key = (struct tipc_aead_key *)nla_data(attr);
+	if (nla_len(attr) < tipc_aead_key_size(*key))
+		return -EINVAL;
+
+	return 0;
+}
+
+static int tipc_nl_retrieve_nodeid(struct nlattr **attrs, u8 **node_id)
+{
+	struct nlattr *attr = attrs[TIPC_NLA_NODE_ID];
+
+	if (!attr)
+		return -ENODATA;
+
+	if (nla_len(attr) < TIPC_NODEID_LEN)
+		return -EINVAL;
+
+	*node_id = (u8 *)nla_data(attr);
+	return 0;
+}
+
+int __tipc_nl_node_set_key(struct sk_buff *skb, struct genl_info *info)
+{
+	struct nlattr *attrs[TIPC_NLA_NODE_MAX + 1];
+	struct net *net = sock_net(skb->sk);
+	struct tipc_net *tn = tipc_net(net);
+	struct tipc_node *n = NULL;
+	struct tipc_aead_key *ukey;
+	struct tipc_crypto *c;
+	u8 *id, *own_id;
+	int rc = 0;
+
+	if (!info->attrs[TIPC_NLA_NODE])
+		return -EINVAL;
+
+	rc = nla_parse_nested(attrs, TIPC_NLA_NODE_MAX,
+			      info->attrs[TIPC_NLA_NODE],
+			      tipc_nl_node_policy, info->extack);
+	if (rc)
+		goto exit;
+
+	own_id = tipc_own_id(net);
+	if (!own_id) {
+		rc = -EPERM;
+		goto exit;
+	}
+
+	rc = tipc_nl_retrieve_key(attrs, &ukey);
+	if (rc)
+		goto exit;
+
+	rc = tipc_aead_key_validate(ukey);
+	if (rc)
+		goto exit;
+
+	rc = tipc_nl_retrieve_nodeid(attrs, &id);
+	switch (rc) {
+	case -ENODATA:
+		/* Cluster key mode */
+		rc = tipc_crypto_key_init(tn->crypto_tx, ukey, CLUSTER_KEY);
+		break;
+	case 0:
+		/* Per-node key mode */
+		if (!memcmp(id, own_id, NODE_ID_LEN)) {
+			c = tn->crypto_tx;
+		} else {
+			n = tipc_node_find_by_id(net, id) ?:
+				tipc_node_create(net, 0, id, 0xffffu, 0, true);
+			if (unlikely(!n)) {
+				rc = -ENOMEM;
+				break;
+			}
+			c = n->crypto_rx;
+		}
+
+		rc = tipc_crypto_key_init(c, ukey, PER_NODE_KEY);
+		if (n)
+			tipc_node_put(n);
+		break;
+	default:
+		break;
+	}
+
+exit:
+	return (rc < 0) ? rc : 0;
+}
+
+int tipc_nl_node_set_key(struct sk_buff *skb, struct genl_info *info)
+{
+	int err;
+
+	rtnl_lock();
+	err = __tipc_nl_node_set_key(skb, info);
+	rtnl_unlock();
+
+	return err;
+}
+
+int __tipc_nl_node_flush_key(struct sk_buff *skb, struct genl_info *info)
+{
+	struct net *net = sock_net(skb->sk);
+	struct tipc_net *tn = tipc_net(net);
+	struct tipc_node *n;
+
+	tipc_crypto_key_flush(tn->crypto_tx);
+	rcu_read_lock();
+	list_for_each_entry_rcu(n, &tn->node_list, list)
+		tipc_crypto_key_flush(n->crypto_rx);
+	rcu_read_unlock();
+
+	pr_info("All keys are flushed!\n");
+	return 0;
+}
+
+int tipc_nl_node_flush_key(struct sk_buff *skb, struct genl_info *info)
+{
+	int err;
+
+	rtnl_lock();
+	err = __tipc_nl_node_flush_key(skb, info);
+	rtnl_unlock();
+
+	return err;
+}
+#endif
+
 /**
  * tipc_node_dump - dump TIPC node data
  * @n: tipc node to be dumped

net/tipc/node.h

···
 int tipc_nl_node_dump_monitor(struct sk_buff *skb, struct netlink_callback *cb);
 int tipc_nl_node_dump_monitor_peer(struct sk_buff *skb,
 				   struct netlink_callback *cb);
+#ifdef CONFIG_TIPC_CRYPTO
+int tipc_nl_node_set_key(struct sk_buff *skb, struct genl_info *info);
+int tipc_nl_node_flush_key(struct sk_buff *skb, struct genl_info *info);
+#endif
 void tipc_node_pre_cleanup_net(struct net *exit_net);
 #endif