[RFCv2,5/9] tcp: authopt: Hook into tcp core

diff --git a/include/net/tcp_authopt.h b/include/net/tcp_authopt.h
index bd5ba95e15de..28ebc77473a4 100644
--- a/include/net/tcp_authopt.h
+++ b/include/net/tcp_authopt.h
@@ -15,10 +15,11 @@  struct tcp_authopt_key_info {
 	/* Wire identifiers */
 	u8 send_id, recv_id;
 	u8 alg_id;
 	u8 keylen;
 	u8 key[TCP_AUTHOPT_MAXKEYLEN];
+	u8 maclen;
 	struct rcu_head rcu;
 	struct sockaddr_storage addr;
 	struct tcp_authopt_alg_imp *alg;
 };
 
@@ -31,15 +32,52 @@  struct tcp_authopt_info {
 	u32 dst_isn;
 	struct rcu_head rcu;
 };
 
 #ifdef CONFIG_TCP_AUTHOPT
+struct tcp_authopt_key_info *tcp_authopt_select_key(const struct sock *sk,
+						    const struct sock *addr_sk,
+						    u8 *rnextkeyid);
 void tcp_authopt_clear(struct sock *sk);
 int tcp_set_authopt(struct sock *sk, sockptr_t optval, unsigned int optlen);
 int tcp_get_authopt_val(struct sock *sk, struct tcp_authopt *key);
 int tcp_set_authopt_key(struct sock *sk, sockptr_t optval, unsigned int optlen);
+int tcp_authopt_hash(
+		char *hash_location,
+		struct tcp_authopt_key_info *key,
+		struct sock *sk, struct sk_buff *skb);
+int __tcp_authopt_openreq(struct sock *newsk, const struct sock *oldsk, struct request_sock *req);
+static inline int tcp_authopt_openreq(
+		struct sock *newsk,
+		const struct sock *oldsk,
+		struct request_sock *req)
+{
+	if (!rcu_dereference(tcp_sk(oldsk)->authopt_info))
+		return 0;
+	else
+		return __tcp_authopt_openreq(newsk, oldsk, req);
+}
+int __tcp_authopt_inbound_check(
+		struct sock *sk,
+		struct sk_buff *skb,
+		struct tcp_authopt_info *info);
+static inline int tcp_authopt_inbound_check(struct sock *sk, struct sk_buff *skb)
+{
+	struct tcp_authopt_info *info = rcu_dereference(tcp_sk(sk)->authopt_info);
+
+	if (info)
+		return __tcp_authopt_inbound_check(sk, skb, info);
+	else
+		return 0;
+}
 #else
+static struct tcp_authopt_key_info *tcp_authopt_select_key(const struct sock *sk,
+							   const struct sock *addr_sk,
+							   u8 *rnextkeyid);
+{
+	return NULL;
+}
 static inline int tcp_set_authopt(struct sock *sk, sockptr_t optval, unsigned int optlen)
 {
 	return -ENOPROTOOPT;
 }
 static inline int tcp_get_authopt_val(struct sock *sk, struct tcp_authopt *key)
@@ -51,8 +89,25 @@  static inline void tcp_authopt_clear(struct sock *sk)
 }
 static inline int tcp_set_authopt_key(struct sock *sk, sockptr_t optval, unsigned int optlen)
 {
 	return -ENOPROTOOPT;
 }
+static inline int tcp_authopt_hash(
+		char *hash_location,
+		struct tcp_authopt_key_info *key,
+		struct sock *sk, struct sk_buff *skb)
+{
+	return -EINVAL;
+}
+static inline int tcp_authopt_openreq(struct sock *newsk,
+				      const struct sock *oldsk,
+				      struct request_sock *req)
+{
+	return 0;
+}
+static inline int tcp_authopt_inbound_check(struct sock *sk, struct sk_buff *skb)
+{
+	return 0;
+}
 #endif
 
 #endif /* _LINUX_TCP_AUTHOPT_H */
diff --git a/net/ipv4/tcp_authopt.c b/net/ipv4/tcp_authopt.c
index a42daadf6b7d..493461e46460 100644
--- a/net/ipv4/tcp_authopt.c
+++ b/net/ipv4/tcp_authopt.c
@@ -168,10 +168,66 @@  struct tcp_authopt_key_info *__tcp_authopt_key_info_lookup(const struct sock *sk
 			return key;
 
 	return NULL;
 }
 
+struct tcp_authopt_key_info *tcp_authopt_lookup_send(struct tcp_authopt_info *info,
+						     const struct sock *addr_sk,
+						     int send_id)
+{
+	struct tcp_authopt_key_info *result = NULL;
+	struct tcp_authopt_key_info *key;
+
+	hlist_for_each_entry_rcu(key, &info->head, node, 0) {
+		if (send_id >= 0 && key->send_id != send_id)
+			continue;
+		if (key->flags & TCP_AUTHOPT_KEY_ADDR_BIND) {
+			if (addr_sk->sk_family == AF_INET) {
+				struct sockaddr_in *key_addr = (struct sockaddr_in *)&key->addr;
+				const struct in_addr *daddr =
+					(const struct in_addr *)&addr_sk->sk_daddr;
+
+				if (WARN_ON(key_addr->sin_family != AF_INET))
+					continue;
+				if (memcmp(daddr, &key_addr->sin_addr, sizeof(*daddr)))
+					continue;
+			}
+			if (addr_sk->sk_family == AF_INET6) {
+				struct sockaddr_in6 *key_addr = (struct sockaddr_in6 *)&key->addr;
+				const struct in6_addr *daddr = &addr_sk->sk_v6_daddr;
+
+				if (WARN_ON(key_addr->sin6_family != AF_INET6))
+					continue;
+				if (memcmp(daddr, &key_addr->sin6_addr, sizeof(*daddr)))
+					continue;
+			}
+		}
+		if (result && net_ratelimit())
+			pr_warn("ambiguous tcp authentication keys configured for send\n");
+		result = key;
+	}
+
+	return result;
+}
+
+/* Select key for sending
+ * addr_sk is the sock used for comparing daddr, it is only different from sk in
+ * the synack case.
+ */
+struct tcp_authopt_key_info *tcp_authopt_select_key(const struct sock *sk,
+						    const struct sock *addr_sk,
+						    u8 *rnextkeyid)
+{
+	struct tcp_authopt_info *info;
+
+	info = rcu_dereference(tcp_sk(sk)->authopt_info);
+	if (!info)
+		return NULL;
+
+	return tcp_authopt_lookup_send(info, addr_sk, -1);
+}
+
 static struct tcp_authopt_info *__tcp_authopt_info_get_or_create(struct sock *sk)
 {
 	struct tcp_sock *tp = tcp_sk(sk);
 	struct tcp_authopt_info *info;
 
@@ -336,16 +392,69 @@  int tcp_set_authopt_key(struct sock *sk, sockptr_t optval, unsigned int optlen)
 	key_info->recv_id = opt.recv_id;
 	key_info->alg_id = opt.alg;
 	key_info->alg = alg;
 	key_info->keylen = opt.keylen;
 	memcpy(key_info->key, opt.key, opt.keylen);
+	key_info->maclen = alg->maclen;
 	memcpy(&key_info->addr, &opt.addr, sizeof(key_info->addr));
 	hlist_add_head_rcu(&key_info->node, &info->head);
 
 	return 0;
 }
 
+static int tcp_authopt_clone_keys(struct sock *newsk,
+				  const struct sock *oldsk,
+				  struct tcp_authopt_info *new_info,
+				  struct tcp_authopt_info *old_info)
+{
+	struct tcp_authopt_key_info *old_key;
+	struct tcp_authopt_key_info *new_key;
+
+	hlist_for_each_entry_rcu(old_key, &old_info->head, node, lockdep_sock_is_held(sk)) {
+		new_key = sock_kmalloc(newsk, sizeof(*new_key), GFP_ATOMIC);
+		if (!new_key)
+			return -ENOMEM;
+		memcpy(new_key, old_key, sizeof(*new_key));
+		tcp_authopt_alg_incref(old_key->alg);
+		hlist_add_head_rcu(&new_key->node, &new_info->head);
+	}
+
+	return 0;
+}
+
+/** Called to create accepted sockets.
+ *
+ *  Need to copy authopt info from listen socket.
+ */
+int __tcp_authopt_openreq(struct sock *newsk, const struct sock *oldsk, struct request_sock *req)
+{
+	struct tcp_authopt_info *old_info;
+	struct tcp_authopt_info *new_info;
+	int err;
+
+	old_info = rcu_dereference(tcp_sk(oldsk)->authopt_info);
+	if (!old_info)
+		return 0;
+
+	new_info = kmalloc(sizeof(*new_info), GFP_ATOMIC | __GFP_ZERO);
+	if (!new_info)
+		return -ENOMEM;
+
+	sk_nocaps_add(newsk, NETIF_F_GSO_MASK);
+	new_info->src_isn = tcp_rsk(req)->snt_isn;
+	new_info->dst_isn = tcp_rsk(req)->rcv_isn;
+	INIT_HLIST_HEAD(&new_info->head);
+	err = tcp_authopt_clone_keys(newsk, oldsk, new_info, old_info);
+	if (err) {
+		__tcp_authopt_info_free(newsk, new_info);
+		return err;
+	}
+	rcu_assign_pointer(tcp_sk(newsk)->authopt_info, new_info);
+
+	return 0;
+}
+
 /* feed traffic key into shash */
 static int tcp_authopt_shash_traffic_key(struct shash_desc *desc,
 					 struct sock *sk,
 					 struct sk_buff *skb,
 					 bool input,
@@ -808,5 +917,123 @@  int __tcp_authopt_calc_mac(struct sock *sk,
 
 out:
 	tcp_authopt_put_mac_shash(key, mac_tfm);
 	return err;
 }
+
+int tcp_authopt_hash(char *hash_location,
+		     struct tcp_authopt_key_info *key,
+		     struct sock *sk,
+		     struct sk_buff *skb)
+{
+	/* MAC inside option is truncated to 12 bytes but crypto API needs output
+	 * buffer to be large enough so we use a buffer on the stack.
+	 */
+	u8 macbuf[TCP_AUTHOPT_MAXMACBUF];
+	int err;
+
+	if (WARN_ON(key->maclen > sizeof(macbuf)))
+		return -ENOBUFS;
+
+	err = __tcp_authopt_calc_mac(sk, skb, key, false, macbuf);
+	if (err) {
+		memset(hash_location, 0, key->maclen);
+		return err;
+	}
+	memcpy(hash_location, macbuf, key->maclen);
+
+	return 0;
+}
+
+static struct tcp_authopt_key_info *tcp_authopt_lookup_recv(struct sock *sk,
+							    struct sk_buff *skb,
+							    struct tcp_authopt_info *info,
+							    int recv_id)
+{
+	struct tcp_authopt_key_info *result = NULL;
+	struct tcp_authopt_key_info *key;
+
+	/* multiple matches will cause occasional failures */
+	hlist_for_each_entry_rcu(key, &info->head, node, 0) {
+		if (recv_id >= 0 && key->recv_id != recv_id)
+			continue;
+		if (key->flags & TCP_AUTHOPT_KEY_ADDR_BIND) {
+			if (sk->sk_family == AF_INET) {
+				struct sockaddr_in *key_addr = (struct sockaddr_in *)&key->addr;
+				struct iphdr *iph = (struct iphdr *)skb_network_header(skb);
+
+				if (WARN_ON(key_addr->sin_family != AF_INET))
+					continue;
+				if (WARN_ON(iph->version != 4))
+					continue;
+				if (memcmp(&iph->saddr, &key_addr->sin_addr, sizeof(iph->saddr)))
+					continue;
+			}
+			if (sk->sk_family == AF_INET6) {
+				struct sockaddr_in6 *key_addr = (struct sockaddr_in6 *)&key->addr;
+				struct ipv6hdr *iph = (struct ipv6hdr *)skb_network_header(skb);
+
+				if (WARN_ON(key_addr->sin6_family != AF_INET6))
+					continue;
+				if (WARN_ON(iph->version != 6))
+					continue;
+				if (memcmp(&iph->saddr, &key_addr->sin6_addr, sizeof(iph->saddr)))
+					continue;
+			}
+		}
+		if (result && net_ratelimit())
+			pr_warn("ambiguous tcp authentication keys configured for receive\n");
+		result = key;
+	}
+
+	return result;
+}
+
+int __tcp_authopt_inbound_check(struct sock *sk, struct sk_buff *skb, struct tcp_authopt_info *info)
+{
+	struct tcphdr *th = (struct tcphdr *)skb_transport_header(skb);
+	struct tcphdr_authopt *opt;
+	struct tcp_authopt_key_info *key;
+	u8 macbuf[16];
+	int err;
+
+	opt = (struct tcphdr_authopt *)tcp_authopt_find_option(th);
+	key = tcp_authopt_lookup_recv(sk, skb, info, opt ? opt->keyid : -1);
+
+	/* nothing found or expected */
+	if (!opt && !key)
+		return 0;
+	if (!opt && key) {
+		net_info_ratelimited("TCP Authentication Missing\n");
+		return -EINVAL;
+	}
+	if (opt && !key) {
+		/* RFC5925 Section 7.3:
+		 * A TCP-AO implementation MUST allow for configuration of the behavior
+		 * of segments with TCP-AO but that do not match an MKT. The initial
+		 * default of this configuration SHOULD be to silently accept such
+		 * connections.
+		 */
+		if (info->flags & TCP_AUTHOPT_FLAG_REJECT_UNEXPECTED) {
+			net_info_ratelimited("TCP Authentication Unexpected: Rejected\n");
+			return -EINVAL;
+		} else {
+			net_info_ratelimited("TCP Authentication Unexpected: Accepted\n");
+			return 0;
+		}
+	}
+
+	/* bad inbound key len */
+	if (key->maclen + 4 != opt->len)
+		return -EINVAL;
+
+	err = __tcp_authopt_calc_mac(sk, skb, key, true, macbuf);
+	if (err)
+		return err;
+
+	if (memcmp(macbuf, opt->mac, key->maclen)) {
+		net_info_ratelimited("TCP Authentication Failed\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 3f7bd7ae7d7a..e0b51b2f747f 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -70,10 +70,11 @@ 
 #include <linux/sysctl.h>
 #include <linux/kernel.h>
 #include <linux/prefetch.h>
 #include <net/dst.h>
 #include <net/tcp.h>
+#include <net/tcp_authopt.h>
 #include <net/inet_common.h>
 #include <linux/ipsec.h>
 #include <asm/unaligned.h>
 #include <linux/errqueue.h>
 #include <trace/events/tcp.h>
@@ -5967,18 +5968,34 @@  void tcp_init_transfer(struct sock *sk, int bpf_op, struct sk_buff *skb)
 	if (!icsk->icsk_ca_initialized)
 		tcp_init_congestion_control(sk);
 	tcp_init_buffer_space(sk);
 }
 
+static void tcp_authopt_finish_connect(struct sock *sk, struct sk_buff *skb)
+{
+#ifdef CONFIG_TCP_AUTHOPT
+	struct tcp_authopt_info *info;
+
+	info = rcu_dereference_protected(tcp_sk(sk)->authopt_info, lockdep_sock_is_held(sk));
+	if (!info)
+		return;
+
+	info->src_isn = ntohl(tcp_hdr(skb)->ack_seq) - 1;
+	info->dst_isn = ntohl(tcp_hdr(skb)->seq);
+#endif
+}
+
 void tcp_finish_connect(struct sock *sk, struct sk_buff *skb)
 {
 	struct tcp_sock *tp = tcp_sk(sk);
 	struct inet_connection_sock *icsk = inet_csk(sk);
 
 	tcp_set_state(sk, TCP_ESTABLISHED);
 	icsk->icsk_ack.lrcvtime = tcp_jiffies32;
 
+	tcp_authopt_finish_connect(sk, skb);
+
 	if (skb) {
 		icsk->icsk_af_ops->sk_rx_dst_set(sk, skb);
 		security_inet_conn_established(sk, skb);
 		sk_mark_napi_id(sk, skb);
 	}
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 1348615c7576..a1d39183908c 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -2060,10 +2060,13 @@  int tcp_v4_rcv(struct sk_buff *skb)
 		goto discard_and_relse;
 
 	if (tcp_v4_inbound_md5_hash(sk, skb, dif, sdif))
 		goto discard_and_relse;
 
+	if (tcp_authopt_inbound_check(sk, skb))
+		goto discard_and_relse;
+
 	nf_reset_ct(skb);
 
 	if (tcp_filter(sk, skb))
 		goto discard_and_relse;
 	th = (const struct tcphdr *)skb->data;
diff --git a/net/ipv4/tcp_minisocks.c b/net/ipv4/tcp_minisocks.c
index 0a4f3f16140a..4d7d86547b0e 100644
--- a/net/ipv4/tcp_minisocks.c
+++ b/net/ipv4/tcp_minisocks.c
@@ -24,10 +24,11 @@ 
 #include <linux/slab.h>
 #include <linux/sysctl.h>
 #include <linux/workqueue.h>
 #include <linux/static_key.h>
 #include <net/tcp.h>
+#include <net/tcp_authopt.h>
 #include <net/inet_common.h>
 #include <net/xfrm.h>
 #include <net/busy_poll.h>
 
 static bool tcp_in_window(u32 seq, u32 end_seq, u32 s_win, u32 e_win)
@@ -539,10 +540,11 @@  struct sock *tcp_create_openreq_child(const struct sock *sk,
 #ifdef CONFIG_TCP_MD5SIG
 	newtp->md5sig_info = NULL;	/*XXX*/
 	if (newtp->af_specific->md5_lookup(sk, newsk))
 		newtp->tcp_header_len += TCPOLEN_MD5SIG_ALIGNED;
 #endif
+	tcp_authopt_openreq(newsk, sk, req);
 	if (skb->len >= TCP_MSS_DEFAULT + newtp->tcp_header_len)
 		newicsk->icsk_ack.last_seg_size = skb->len - newtp->tcp_header_len;
 	newtp->rx_opt.mss_clamp = req->mss;
 	tcp_ecn_openreq_child(newtp, req);
 	newtp->fastopen_req = NULL;
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 29553fce8502..0e9ed6578809 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -37,10 +37,11 @@ 
 
 #define pr_fmt(fmt) "TCP: " fmt
 
 #include <net/tcp.h>
 #include <net/mptcp.h>
+#include <net/tcp_authopt.h>
 
 #include <linux/compiler.h>
 #include <linux/gfp.h>
 #include <linux/module.h>
 #include <linux/static_key.h>
@@ -411,10 +412,11 @@  static inline bool tcp_urg_mode(const struct tcp_sock *tp)
 
 #define OPTION_SACK_ADVERTISE	(1 << 0)
 #define OPTION_TS		(1 << 1)
 #define OPTION_MD5		(1 << 2)
 #define OPTION_WSCALE		(1 << 3)
+#define OPTION_AUTHOPT		(1 << 4)
 #define OPTION_FAST_OPEN_COOKIE	(1 << 8)
 #define OPTION_SMC		(1 << 9)
 #define OPTION_MPTCP		(1 << 10)
 
 static void smc_options_write(__be32 *ptr, u16 *options)
@@ -435,16 +437,21 @@  static void smc_options_write(__be32 *ptr, u16 *options)
 struct tcp_out_options {
 	u16 options;		/* bit field of OPTION_* */
 	u16 mss;		/* 0 to disable */
 	u8 ws;			/* window scale, 0 to disable */
 	u8 num_sack_blocks;	/* number of SACK blocks to include */
-	u8 hash_size;		/* bytes in hash_location */
 	u8 bpf_opt_len;		/* length of BPF hdr option */
+#ifdef CONFIG_TCP_AUTHOPT
+	u8 authopt_rnextkeyid; /* rnextkey */
+#endif
 	__u8 *hash_location;	/* temporary pointer, overloaded */
 	__u32 tsval, tsecr;	/* need to include OPTION_TS */
 	struct tcp_fastopen_cookie *fastopen_cookie;	/* Fast open cookie */
 	struct mptcp_out_options mptcp;
+#ifdef CONFIG_TCP_AUTHOPT
+	struct tcp_authopt_key_info *authopt_key;
+#endif
 };
 
 static void mptcp_options_write(__be32 *ptr, const struct tcp_sock *tp,
 				struct tcp_out_options *opts)
 {
@@ -617,10 +624,24 @@  static void tcp_options_write(__be32 *ptr, struct tcp_sock *tp,
 		/* overload cookie hash location */
 		opts->hash_location = (__u8 *)ptr;
 		ptr += 4;
 	}
 
+#ifdef CONFIG_TCP_AUTHOPT
+	if (unlikely(OPTION_AUTHOPT & options)) {
+		struct tcp_authopt_key_info *key = opts->authopt_key;
+
+		WARN_ON(!key);
+		*ptr++ = htonl((TCPOPT_AUTHOPT << 24) | ((4 + key->maclen) << 16) |
+			       (key->send_id << 8) | opts->authopt_rnextkeyid);
+		/* overload cookie hash location */
+		opts->hash_location = (__u8 *)ptr;
+		/* maclen is currently always 12 but try to align nicely anyway. */
+		ptr += (key->maclen + 3) / 4;
+	}
+#endif
+
 	if (unlikely(opts->mss)) {
 		*ptr++ = htonl((TCPOPT_MSS << 24) |
 			       (TCPOLEN_MSS << 16) |
 			       opts->mss);
 	}
@@ -752,10 +773,28 @@  static void mptcp_set_option_cond(const struct request_sock *req,
 			}
 		}
 	}
 }
 
+static int tcp_authopt_init_options(const struct sock *sk,
+				    const struct sock *addr_sk,
+				    struct tcp_out_options *opts)
+{
+#ifdef CONFIG_TCP_AUTHOPT
+	struct tcp_authopt_key_info *key;
+
+	key = tcp_authopt_select_key(sk, addr_sk, &opts->authopt_rnextkeyid);
+	if (key) {
+		opts->options |= OPTION_AUTHOPT;
+		opts->authopt_key = key;
+		return 4 + key->maclen;
+	}
+#endif
+
+	return 0;
+}
+
 /* Compute TCP options for SYN packets. This is not the final
  * network wire format yet.
  */
 static unsigned int tcp_syn_options(struct sock *sk, struct sk_buff *skb,
 				struct tcp_out_options *opts,
@@ -774,10 +813,11 @@  static unsigned int tcp_syn_options(struct sock *sk, struct sk_buff *skb,
 			opts->options |= OPTION_MD5;
 			remaining -= TCPOLEN_MD5SIG_ALIGNED;
 		}
 	}
 #endif
+	remaining -= tcp_authopt_init_options(sk, sk, opts);
 
 	/* We always get an MSS option.  The option bytes which will be seen in
 	 * normal data packets should timestamps be used, must be in the MSS
 	 * advertised.  But we subtract them from tp->mss_cache so that
 	 * calculations in tcp_sendmsg are simpler etc.  So account for this
@@ -862,10 +902,11 @@  static unsigned int tcp_synack_options(const struct sock *sk,
 		 */
 		if (synack_type != TCP_SYNACK_COOKIE)
 			ireq->tstamp_ok &= !ireq->sack_ok;
 	}
 #endif
+	remaining -= tcp_authopt_init_options(sk, req_to_sk(req), opts);
 
 	/* We always send an MSS option. */
 	opts->mss = mss;
 	remaining -= TCPOLEN_MSS_ALIGNED;
 
@@ -930,10 +971,11 @@  static unsigned int tcp_established_options(struct sock *sk, struct sk_buff *skb
 			opts->options |= OPTION_MD5;
 			size += TCPOLEN_MD5SIG_ALIGNED;
 		}
 	}
 #endif
+	size += tcp_authopt_init_options(sk, sk, opts);
 
 	if (likely(tp->rx_opt.tstamp_ok)) {
 		opts->options |= OPTION_TS;
 		opts->tsval = skb ? tcp_skb_timestamp(skb) + tp->tsoffset : 0;
 		opts->tsecr = tp->rx_opt.ts_recent;
@@ -1365,10 +1407,17 @@  static int __tcp_transmit_skb(struct sock *sk, struct sk_buff *skb,
 		sk_nocaps_add(sk, NETIF_F_GSO_MASK);
 		tp->af_specific->calc_md5_hash(opts.hash_location,
 					       md5, sk, skb);
 	}
 #endif
+#ifdef CONFIG_TCP_AUTHOPT
+	if (opts.authopt_key) {
+		sk_nocaps_add(sk, NETIF_F_GSO_MASK);
+		err = tcp_authopt_hash(opts.hash_location, opts.authopt_key, sk, skb);
+		WARN_ON(err); // FIXME
+	}
+#endif
 
 	/* BPF prog is the last one writing header option */
 	bpf_skops_write_hdr_opt(sk, skb, NULL, NULL, 0, &opts);
 
 	INDIRECT_CALL_INET(icsk->icsk_af_ops->send_check,
@@ -3602,10 +3651,15 @@  struct sk_buff *tcp_make_synack(const struct sock *sk, struct dst_entry *dst,
 	if (md5)
 		tcp_rsk(req)->af_specific->calc_md5_hash(opts.hash_location,
 					       md5, req_to_sk(req), skb);
 	rcu_read_unlock();
 #endif
+#ifdef CONFIG_TCP_AUTHOPT
+	/* If signature fails we do nothing */
+	if (opts.authopt_key)
+		tcp_authopt_hash(opts.hash_location, opts.authopt_key, req_to_sk(req), skb);
+#endif
 
 	bpf_skops_write_hdr_opt((struct sock *)sk, skb, req, syn_skb,
 				synack_type, &opts);
 
 	skb->skb_mstamp_ns = now;
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 0ce52d46e4f8..51381a9c2bd5 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -40,10 +40,11 @@ 
 #include <linux/icmpv6.h>
 #include <linux/random.h>
 #include <linux/indirect_call_wrapper.h>
 
 #include <net/tcp.h>
+#include <net/tcp_authopt.h>
 #include <net/ndisc.h>
 #include <net/inet6_hashtables.h>
 #include <net/inet6_connection_sock.h>
 #include <net/ipv6.h>
 #include <net/transp_v6.h>
@@ -1733,10 +1734,13 @@  INDIRECT_CALLABLE_SCOPE int tcp_v6_rcv(struct sk_buff *skb)
 		goto discard_and_relse;
 
 	if (tcp_v6_inbound_md5_hash(sk, skb, dif, sdif))
 		goto discard_and_relse;
 
+	if (tcp_authopt_inbound_check(sk, skb))
+		goto discard_and_relse;
+
 	if (tcp_filter(sk, skb))
 		goto discard_and_relse;
 	th = (const struct tcphdr *)skb->data;
 	hdr = ipv6_hdr(skb);
 	tcp_v6_fill_cb(skb, hdr, th);