net/tcp: Add TCP-AO sign to twsk

Add support for sockets in time-wait state.
ao_info as well as all keys are inherited on transition to time-wait
socket. The lifetime of ao_info is now protected by ref counter, so
that tcp_ao_destroy_sock() will destruct it only when the last user is
gone.

Co-developed-by: Francesco Ruggeri <fruggeri@arista.com>
Signed-off-by: Francesco Ruggeri <fruggeri@arista.com>
Co-developed-by: Salam Noureddine <noureddine@arista.com>
Signed-off-by: Salam Noureddine <noureddine@arista.com>
Signed-off-by: Dmitry Safonov <dima@arista.com>
Acked-by: David Ahern <dsahern@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 53 insertions, 19 deletions

diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 45b81e230438..e6c3617976f0 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -778,13 +778,6 @@ clear_hash_nostart:
 	memset(md5_hash, 0, 16);
 	return 1;
 }
-#else /* CONFIG_TCP_MD5SIG */
-static struct tcp_md5sig_key *tcp_v6_md5_do_lookup(const struct sock *sk,
-						   const struct in6_addr *addr,
-						   int l3index)
-{
-	return NULL;
-}
 #endif
 
 static void tcp_v6_init_req(struct request_sock *req,
@@ -1134,39 +1127,81 @@ out:
 
 static void tcp_v6_send_ack(const struct sock *sk, struct sk_buff *skb, u32 seq,
 			    u32 ack, u32 win, u32 tsval, u32 tsecr, int oif,
-			    struct tcp_md5sig_key *md5_key, u8 tclass,
+			    struct tcp_key *key, u8 tclass,
 			    __be32 label, u32 priority, u32 txhash)
 {
-	struct tcp_key key = {
-				.md5_key = md5_key,
-				.type = md5_key ? TCP_KEY_MD5 : TCP_KEY_NONE,
-	};
-
 	tcp_v6_send_response(sk, skb, seq, ack, win, tsval, tsecr, oif, 0,
-			     tclass, label, priority, txhash, &key);
+			     tclass, label, priority, txhash, key);
 }
 
 static void tcp_v6_timewait_ack(struct sock *sk, struct sk_buff *skb)
 {
 	struct inet_timewait_sock *tw = inet_twsk(sk);
 	struct tcp_timewait_sock *tcptw = tcp_twsk(sk);
+	struct tcp_key key = {};
+#ifdef CONFIG_TCP_AO
+	struct tcp_ao_info *ao_info;
+
+	/* FIXME: the segment to-be-acked is not verified yet */
+	ao_info = rcu_dereference(tcptw->ao_info);
+	if (ao_info) {
+		const struct tcp_ao_hdr *aoh;
+
+		/* Invalid TCP option size or twice included auth */
+		if (tcp_parse_auth_options(tcp_hdr(skb), NULL, &aoh))
+			goto out;
+		if (aoh) {
+			key.ao_key = tcp_ao_established_key(ao_info,
+							    aoh->rnext_keyid, -1);
+		}
+	}
+	if (key.ao_key) {
+		struct tcp_ao_key *rnext_key;
+
+		key.traffic_key = snd_other_key(key.ao_key);
+		/* rcv_next switches to our rcv_next */
+		rnext_key = READ_ONCE(ao_info->rnext_key);
+		key.rcv_next = rnext_key->rcvid;
+		key.type = TCP_KEY_AO;
+#else
+	if (0) {
+#endif
+#ifdef CONFIG_TCP_MD5SIG
+	} else if (static_branch_unlikely(&tcp_md5_needed.key)) {
+		key.md5_key = tcp_twsk_md5_key(tcptw);
+		if (key.md5_key)
+			key.type = TCP_KEY_MD5;
+#endif
+	}
 
 	tcp_v6_send_ack(sk, skb, tcptw->tw_snd_nxt, tcptw->tw_rcv_nxt,
 			tcptw->tw_rcv_wnd >> tw->tw_rcv_wscale,
 			tcp_tw_tsval(tcptw),
-			tcptw->tw_ts_recent, tw->tw_bound_dev_if, tcp_twsk_md5_key(tcptw),
+			tcptw->tw_ts_recent, tw->tw_bound_dev_if, &key,
 			tw->tw_tclass, cpu_to_be32(tw->tw_flowlabel), tw->tw_priority,
 			tw->tw_txhash);
 
+#ifdef CONFIG_TCP_AO
+out:
+#endif
 	inet_twsk_put(tw);
 }
 
 static void tcp_v6_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
 				  struct request_sock *req)
 {
-	int l3index;
+	struct tcp_key key = {};
+
+#ifdef CONFIG_TCP_MD5SIG
+	if (static_branch_unlikely(&tcp_md5_needed.key)) {
+		int l3index = tcp_v6_sdif(skb) ? tcp_v6_iif_l3_slave(skb) : 0;
 
-	l3index = tcp_v6_sdif(skb) ? tcp_v6_iif_l3_slave(skb) : 0;
+		key.md5_key = tcp_v6_md5_do_lookup(sk, &ipv6_hdr(skb)->saddr,
+						   l3index);
+		if (key.md5_key)
+			key.type = TCP_KEY_MD5;
+	}
+#endif
 
 	/* sk->sk_state == TCP_LISTEN -> for regular TCP_SYN_RECV
 	 * sk->sk_state == TCP_SYN_RECV -> for Fast Open.
@@ -1182,8 +1217,7 @@ static void tcp_v6_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb,
 			req->rsk_rcv_wnd >> inet_rsk(req)->rcv_wscale,
 			tcp_rsk_tsval(tcp_rsk(req)),
 			READ_ONCE(req->ts_recent), sk->sk_bound_dev_if,
-			tcp_v6_md5_do_lookup(sk, &ipv6_hdr(skb)->saddr, l3index),
-			ipv6_get_dsfield(ipv6_hdr(skb)), 0,
+			&key, ipv6_get_dsfield(ipv6_hdr(skb)), 0,
 			READ_ONCE(sk->sk_priority),
 			READ_ONCE(tcp_rsk(req)->txhash));
 }