Merge branch 'tipc-add-more-features-to-TIPC-encryption'

Tuong Lien says:

====================
tipc: add more features to TIPC encryption

This series adds some new features to TIPC encryption:

- Patch 1 ("tipc: optimize key switching time and logic") optimizes the
code and logic in preparation for the following commits.

- Patch 2 ("tipc: introduce encryption master key") introduces support
of 'master key' for authentication of new nodes and key exchange. A
master key can be set/changed by user via netlink (eg. using the same
'tipc node set key' command in iproute2/tipc).

- Patch 3 ("tipc: add automatic session key exchange") allows a session
key to be securely exchanged between nodes as needed.

- Patch 4 ("tipc: add automatic rekeying for encryption key") adds
automatic 'rekeying' of session keys a specific interval. The new key
will be distributed automatically to peer nodes, so become active then.
The rekeying interval is configurable via netlink as well.

v2: update the "tipc: add automatic session key exchange" patch to fix
"implicit declaration" issue when built without "CONFIG_TIPC_CRYPTO".

v3: update the patches according to David comments by using the
"genl_info->extack" for messages in response to netlink user config
requests.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

include/uapi/linux/tipc.h

@@ -254,6 +254,8 @@ static inline int tipc_aead_key_size(struct tipc_aead_key *key)
 	return sizeof(*key) + key->keylen;
 }
 
+#define TIPC_REKEYING_NOW		(~0U)
+
 /* The macros and functions below are deprecated:
  */
 

include/uapi/linux/tipc_netlink.h

@@ -165,6 +165,8 @@ enum {
 	TIPC_NLA_NODE_UP,		/* flag */
 	TIPC_NLA_NODE_ID,		/* data */
 	TIPC_NLA_NODE_KEY,		/* data */
+	TIPC_NLA_NODE_KEY_MASTER,	/* flag */
+	TIPC_NLA_NODE_REKEYING,		/* u32 */
 
 	__TIPC_NLA_NODE_MAX,
 	TIPC_NLA_NODE_MAX = __TIPC_NLA_NODE_MAX - 1

net/tipc/crypto.h

@@ -67,6 +67,7 @@ enum {
 };
 
 extern int sysctl_tipc_max_tfms __read_mostly;
+extern int sysctl_tipc_key_exchange_enabled __read_mostly;
 
 /**
  * TIPC encryption message format:
@@ -74,7 +75,7 @@ extern int sysctl_tipc_max_tfms __read_mostly;
  *     3 3 2 2 2 2 2 2 2 2 2 2 1 1 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0
  *     1 0 9 8 7 6 5 4|3 2 1 0 9 8 7 6|5 4 3 2 1 0 9 8|7 6 5 4 3 2 1 0
  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
- * w0:|Ver=7| User  |D|TX |RX |K|                 Rsvd                |
+ * w0:|Ver=7| User  |D|TX |RX |K|M|N|             Rsvd                |
  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  * w1:|                             Seqno                             |
  * w2:|                           (8 octets)                          |
@@ -101,6 +102,9 @@ extern int sysctl_tipc_max_tfms __read_mostly;
  *	RX	: Currently RX active key corresponding to the destination
  *	          node's TX key (when the "D" bit is set)
  *	K	: Keep-alive bit (for RPS, LINK_PROTOCOL/STATE_MSG only)
+ *	M       : Bit indicates if sender has master key
+ *	N	: Bit indicates if sender has no RX keys corresponding to the
+ *	          receiver's TX (when the "D" bit is set)
  *	Rsvd	: Reserved bit, field
  * Word1-2:
  *	Seqno	: The 64-bit sequence number of the encrypted message, also
@@ -117,7 +121,9 @@ struct tipc_ehdr {
 			__u8	destined:1,
 				user:4,
 				version:3;
-			__u8	reserved_1:3,
+			__u8	reserved_1:1,
+				rx_nokey:1,
+				master_key:1,
 				keepalive:1,
 				rx_key_active:2,
 				tx_key:2;
@@ -128,7 +134,9 @@ struct tipc_ehdr {
 			__u8	tx_key:2,
 				rx_key_active:2,
 				keepalive:1,
-				reserved_1:3;
+				master_key:1,
+				rx_nokey:1,
+				reserved_1:1;
 #else
 #error  "Please fix <asm/byteorder.h>"
 #endif
@@ -158,10 +166,35 @@ int tipc_crypto_xmit(struct net *net, struct sk_buff **skb,
 int tipc_crypto_rcv(struct net *net, struct tipc_crypto *rx,
 		    struct sk_buff **skb, struct tipc_bearer *b);
 int tipc_crypto_key_init(struct tipc_crypto *c, struct tipc_aead_key *ukey,
-			 u8 mode);
+			 u8 mode, bool master_key);
 void tipc_crypto_key_flush(struct tipc_crypto *c);
-int tipc_aead_key_validate(struct tipc_aead_key *ukey);
+int tipc_crypto_key_distr(struct tipc_crypto *tx, u8 key,
+			  struct tipc_node *dest);
+void tipc_crypto_msg_rcv(struct net *net, struct sk_buff *skb);
+void tipc_crypto_rekeying_sched(struct tipc_crypto *tx, bool changed,
+				u32 new_intv);
+int tipc_aead_key_validate(struct tipc_aead_key *ukey, struct genl_info *info);
 bool tipc_ehdr_validate(struct sk_buff *skb);
 
+static inline u32 msg_key_gen(struct tipc_msg *m)
+{
+	return msg_bits(m, 4, 16, 0xffff);
+}
+
+static inline void msg_set_key_gen(struct tipc_msg *m, u32 gen)
+{
+	msg_set_bits(m, 4, 16, 0xffff, gen);
+}
+
+static inline u32 msg_key_mode(struct tipc_msg *m)
+{
+	return msg_bits(m, 4, 0, 0xf);
+}
+
+static inline void msg_set_key_mode(struct tipc_msg *m, u32 mode)
+{
+	msg_set_bits(m, 4, 0, 0xf, mode);
+}
+
 #endif /* _TIPC_CRYPTO_H */
 #endif

net/tipc/link.c

@@ -1250,6 +1250,11 @@ static bool tipc_data_input(struct tipc_link *l, struct sk_buff *skb,
 	case MSG_FRAGMENTER:
 	case BCAST_PROTOCOL:
 		return false;
+#ifdef CONFIG_TIPC_CRYPTO
+	case MSG_CRYPTO:
+		tipc_crypto_msg_rcv(l->net, skb);
+		return true;
+#endif
 	default:
 		pr_warn("Dropping received illegal msg type\n");
 		kfree_skb(skb);

net/tipc/msg.h

@@ -82,6 +82,7 @@ struct plist;
 #define  NAME_DISTRIBUTOR     11
 #define  MSG_FRAGMENTER       12
 #define  LINK_CONFIG          13
+#define  MSG_CRYPTO           14
 #define  SOCK_WAKEUP          14       /* pseudo user */
 #define  TOP_SRV              15       /* pseudo user */
 
@@ -127,7 +128,9 @@ struct tipc_skb_cb {
 #ifdef CONFIG_TIPC_CRYPTO
 			u8 encrypted:1;
 			u8 decrypted:1;
-			u8 probe:1;
+#define SKB_PROBING	1
+#define SKB_GRACING	2
+			u8 xmit_type:2;
 			u8 tx_clone_deferred:1;
 #endif
 		};
@@ -747,6 +750,9 @@ static inline void msg_set_nameupper(struct tipc_msg *m, u32 n)
 #define GRP_RECLAIM_MSG      4
 #define GRP_REMIT_MSG        5
 
+/* Crypto message types */
+#define KEY_DISTR_MSG		0
+
 /*
  * Word 1
  */

net/tipc/netlink.c

@@ -108,6 +108,8 @@ const struct nla_policy tipc_nl_node_policy[TIPC_NLA_NODE_MAX + 1] = {
 					    .len = TIPC_NODEID_LEN},
 	[TIPC_NLA_NODE_KEY]		= { .type = NLA_BINARY,
 					    .len = TIPC_AEAD_KEY_SIZE_MAX},
+	[TIPC_NLA_NODE_KEY_MASTER]	= { .type = NLA_FLAG },
+	[TIPC_NLA_NODE_REKEYING]	= { .type = NLA_U32 },
 };
 
 /* Properties valid for media, bearer and link */

net/tipc/node.c

@@ -278,6 +278,14 @@ struct tipc_crypto *tipc_node_crypto_rx_by_list(struct list_head *pos)
 {
 	return container_of(pos, struct tipc_node, list)->crypto_rx;
 }
+
+struct tipc_crypto *tipc_node_crypto_rx_by_addr(struct net *net, u32 addr)
+{
+	struct tipc_node *n;
+
+	n = tipc_node_find(net, addr);
+	return (n) ? n->crypto_rx : NULL;
+}
 #endif
 
 static void tipc_node_free(struct rcu_head *rp)
@@ -303,7 +311,7 @@ void tipc_node_put(struct tipc_node *node)
 	kref_put(&node->kref, tipc_node_kref_release);
 }
 
-static void tipc_node_get(struct tipc_node *node)
+void tipc_node_get(struct tipc_node *node)
 {
 	kref_get(&node->kref);
 }
@@ -584,6 +592,9 @@ static void tipc_node_calculate_timer(struct tipc_node *n, struct tipc_link *l)
 
 static void tipc_node_delete_from_list(struct tipc_node *node)
 {
+#ifdef CONFIG_TIPC_CRYPTO
+	tipc_crypto_key_flush(node->crypto_rx);
+#endif
 	list_del_rcu(&node->list);
 	hlist_del_rcu(&node->hash);
 	tipc_node_put(node);
@@ -2868,15 +2879,27 @@ static int tipc_nl_retrieve_nodeid(struct nlattr **attrs, u8 **node_id)
 	return 0;
 }
 
+static int tipc_nl_retrieve_rekeying(struct nlattr **attrs, u32 *intv)
+{
+	struct nlattr *attr = attrs[TIPC_NLA_NODE_REKEYING];
+
+	if (!attr)
+		return -ENODATA;
+
+	*intv = nla_get_u32(attr);
+	return 0;
+}
+
 static 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_crypto *tx = tipc_net(net)->crypto_tx, *c = tx;
 	struct tipc_node *n = NULL;
 	struct tipc_aead_key *ukey;
-	struct tipc_crypto *c;
-	u8 *id, *own_id;
+	bool rekeying = true, master_key = false;
+	u8 *id, *own_id, mode;
+	u32 intv = 0;
 	int rc = 0;
 
 	if (!info->attrs[TIPC_NLA_NODE])
@@ -2886,52 +2909,66 @@ static int __tipc_nl_node_set_key(struct sk_buff *skb, struct genl_info *info)
 			      info->attrs[TIPC_NLA_NODE],
 			      tipc_nl_node_policy, info->extack);
 	if (rc)
-		goto exit;
+		return rc;
 
 	own_id = tipc_own_id(net);
 	if (!own_id) {
-		rc = -EPERM;
-		goto exit;
+		GENL_SET_ERR_MSG(info, "not found own node identity (set id?)");
+		return -EPERM;
 	}
 
+	rc = tipc_nl_retrieve_rekeying(attrs, &intv);
+	if (rc == -ENODATA)
+		rekeying = false;
+
 	rc = tipc_nl_retrieve_key(attrs, &ukey);
-	if (rc)
-		goto exit;
+	if (rc == -ENODATA && rekeying)
+		goto rekeying;
+	else if (rc)
+		return rc;
 
-	rc = tipc_aead_key_validate(ukey);
+	rc = tipc_aead_key_validate(ukey, info);
 	if (rc)
-		goto exit;
+		return rc;
 
 	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);
+		mode = CLUSTER_KEY;
+		master_key = !!(attrs[TIPC_NLA_NODE_KEY_MASTER]);
 		break;
 	case 0:
-		/* Per-node key mode */
-		if (!memcmp(id, own_id, NODE_ID_LEN)) {
-			c = tn->crypto_tx;
-		} else {
+		mode = PER_NODE_KEY;
+		if (memcmp(id, own_id, NODE_ID_LEN)) {
 			n = tipc_node_find_by_id(net, id) ?:
 				tipc_node_create(net, 0, id, 0xffffu, 0, true);
-			if (unlikely(!n)) {
-				rc = -ENOMEM;
-				break;
-			}
+			if (unlikely(!n))
+				return -ENOMEM;
 			c = n->crypto_rx;
 		}
-
-		rc = tipc_crypto_key_init(c, ukey, PER_NODE_KEY);
-		if (n)
-			tipc_node_put(n);
 		break;
 	default:
-		break;
+		return rc;
 	}
 
-exit:
-	return (rc < 0) ? rc : 0;
+	/* Initiate the TX/RX key */
+	rc = tipc_crypto_key_init(c, ukey, mode, master_key);
+	if (n)
+		tipc_node_put(n);
+
+	if (unlikely(rc < 0)) {
+		GENL_SET_ERR_MSG(info, "unable to initiate or attach new key");
+		return rc;
+	} else if (c == tx) {
+		/* Distribute TX key but not master one */
+		if (!master_key && tipc_crypto_key_distr(tx, rc, NULL))
+			GENL_SET_ERR_MSG(info, "failed to replicate new key");
+rekeying:
+		/* Schedule TX rekeying if needed */
+		tipc_crypto_rekeying_sched(tx, rekeying, intv);
+	}
+
+	return 0;
 }
 
 int tipc_nl_node_set_key(struct sk_buff *skb, struct genl_info *info)
@@ -2958,7 +2995,6 @@ static int __tipc_nl_node_flush_key(struct sk_buff *skb,
 		tipc_crypto_key_flush(n->crypto_rx);
 	rcu_read_unlock();
 
-	pr_info("All keys are flushed!\n");
 	return 0;
 }
 

net/tipc/node.h

@@ -79,12 +79,14 @@ bool tipc_node_get_id(struct net *net, u32 addr, u8 *id);
 u32 tipc_node_get_addr(struct tipc_node *node);
 char *tipc_node_get_id_str(struct tipc_node *node);
 void tipc_node_put(struct tipc_node *node);
+void tipc_node_get(struct tipc_node *node);
 struct tipc_node *tipc_node_create(struct net *net, u32 addr, u8 *peer_id,
 				   u16 capabilities, u32 hash_mixes,
 				   bool preliminary);
 #ifdef CONFIG_TIPC_CRYPTO
 struct tipc_crypto *tipc_node_crypto_rx(struct tipc_node *__n);
 struct tipc_crypto *tipc_node_crypto_rx_by_list(struct list_head *pos);
+struct tipc_crypto *tipc_node_crypto_rx_by_addr(struct net *net, u32 addr);
 #endif
 u32 tipc_node_try_addr(struct net *net, u8 *id, u32 addr);
 void tipc_node_check_dest(struct net *net, u32 onode, u8 *peer_id128,

net/tipc/sysctl.c

@@ -74,6 +74,15 @@ static struct ctl_table tipc_table[] = {
 		.proc_handler	= proc_dointvec_minmax,
 		.extra1         = SYSCTL_ONE,
 	},
+	{
+		.procname	= "key_exchange_enabled",
+		.data		= &sysctl_tipc_key_exchange_enabled,
+		.maxlen		= sizeof(sysctl_tipc_key_exchange_enabled),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1         = SYSCTL_ZERO,
+		.extra2         = SYSCTL_ONE,
+	},
 #endif
 	{
 		.procname	= "bc_retruni",