Merging upstream version 6.7.7.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 2396 insertions, 0 deletions

diff --git a/net/ipv4/tcp_ao.c b/net/ipv4/tcp_ao.c
new file mode 100644
index 0000000000..f8308d3f56
--- /dev/null
+++ b/net/ipv4/tcp_ao.c
@@ -0,0 +1,2396 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * INET		An implementation of the TCP Authentication Option (TCP-AO).
+ *		See RFC5925.
+ *
+ * Authors:	Dmitry Safonov <dima@arista.com>
+ *		Francesco Ruggeri <fruggeri@arista.com>
+ *		Salam Noureddine <noureddine@arista.com>
+ */
+#define pr_fmt(fmt) "TCP: " fmt
+
+#include <crypto/hash.h>
+#include <linux/inetdevice.h>
+#include <linux/tcp.h>
+
+#include <net/tcp.h>
+#include <net/ipv6.h>
+#include <net/icmp.h>
+
+DEFINE_STATIC_KEY_DEFERRED_FALSE(tcp_ao_needed, HZ);
+
+int tcp_ao_calc_traffic_key(struct tcp_ao_key *mkt, u8 *key, void *ctx,
+			    unsigned int len, struct tcp_sigpool *hp)
+{
+	struct scatterlist sg;
+	int ret;
+
+	if (crypto_ahash_setkey(crypto_ahash_reqtfm(hp->req),
+				mkt->key, mkt->keylen))
+		goto clear_hash;
+
+	ret = crypto_ahash_init(hp->req);
+	if (ret)
+		goto clear_hash;
+
+	sg_init_one(&sg, ctx, len);
+	ahash_request_set_crypt(hp->req, &sg, key, len);
+	crypto_ahash_update(hp->req);
+
+	ret = crypto_ahash_final(hp->req);
+	if (ret)
+		goto clear_hash;
+
+	return 0;
+clear_hash:
+	memset(key, 0, tcp_ao_digest_size(mkt));
+	return 1;
+}
+
+bool tcp_ao_ignore_icmp(const struct sock *sk, int family, int type, int code)
+{
+	bool ignore_icmp = false;
+	struct tcp_ao_info *ao;
+
+	if (!static_branch_unlikely(&tcp_ao_needed.key))
+		return false;
+
+	/* RFC5925, 7.8:
+	 * >> A TCP-AO implementation MUST default to ignore incoming ICMPv4
+	 * messages of Type 3 (destination unreachable), Codes 2-4 (protocol
+	 * unreachable, port unreachable, and fragmentation needed -- ’hard
+	 * errors’), and ICMPv6 Type 1 (destination unreachable), Code 1
+	 * (administratively prohibited) and Code 4 (port unreachable) intended
+	 * for connections in synchronized states (ESTABLISHED, FIN-WAIT-1, FIN-
+	 * WAIT-2, CLOSE-WAIT, CLOSING, LAST-ACK, TIME-WAIT) that match MKTs.
+	 */
+	if (family == AF_INET) {
+		if (type != ICMP_DEST_UNREACH)
+			return false;
+		if (code < ICMP_PROT_UNREACH || code > ICMP_FRAG_NEEDED)
+			return false;
+	} else {
+		if (type != ICMPV6_DEST_UNREACH)
+			return false;
+		if (code != ICMPV6_ADM_PROHIBITED && code != ICMPV6_PORT_UNREACH)
+			return false;
+	}
+
+	rcu_read_lock();
+	switch (sk->sk_state) {
+	case TCP_TIME_WAIT:
+		ao = rcu_dereference(tcp_twsk(sk)->ao_info);
+		break;
+	case TCP_SYN_SENT:
+	case TCP_SYN_RECV:
+	case TCP_LISTEN:
+	case TCP_NEW_SYN_RECV:
+		/* RFC5925 specifies to ignore ICMPs *only* on connections
+		 * in synchronized states.
+		 */
+		rcu_read_unlock();
+		return false;
+	default:
+		ao = rcu_dereference(tcp_sk(sk)->ao_info);
+	}
+
+	if (ao && !ao->accept_icmps) {
+		ignore_icmp = true;
+		__NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPAODROPPEDICMPS);
+		atomic64_inc(&ao->counters.dropped_icmp);
+	}
+	rcu_read_unlock();
+
+	return ignore_icmp;
+}
+
+/* Optimized version of tcp_ao_do_lookup(): only for sockets for which
+ * it's known that the keys in ao_info are matching peer's
+ * family/address/VRF/etc.
+ */
+struct tcp_ao_key *tcp_ao_established_key(struct tcp_ao_info *ao,
+					  int sndid, int rcvid)
+{
+	struct tcp_ao_key *key;
+
+	hlist_for_each_entry_rcu(key, &ao->head, node) {
+		if ((sndid >= 0 && key->sndid != sndid) ||
+		    (rcvid >= 0 && key->rcvid != rcvid))
+			continue;
+		return key;
+	}
+
+	return NULL;
+}
+
+static int ipv4_prefix_cmp(const struct in_addr *addr1,
+			   const struct in_addr *addr2,
+			   unsigned int prefixlen)
+{
+	__be32 mask = inet_make_mask(prefixlen);
+	__be32 a1 = addr1->s_addr & mask;
+	__be32 a2 = addr2->s_addr & mask;
+
+	if (a1 == a2)
+		return 0;
+	return memcmp(&a1, &a2, sizeof(a1));
+}
+
+static int __tcp_ao_key_cmp(const struct tcp_ao_key *key, int l3index,
+			    const union tcp_ao_addr *addr, u8 prefixlen,
+			    int family, int sndid, int rcvid)
+{
+	if (sndid >= 0 && key->sndid != sndid)
+		return (key->sndid > sndid) ? 1 : -1;
+	if (rcvid >= 0 && key->rcvid != rcvid)
+		return (key->rcvid > rcvid) ? 1 : -1;
+	if (l3index >= 0 && (key->keyflags & TCP_AO_KEYF_IFINDEX)) {
+		if (key->l3index != l3index)
+			return (key->l3index > l3index) ? 1 : -1;
+	}
+
+	if (family == AF_UNSPEC)
+		return 0;
+	if (key->family != family)
+		return (key->family > family) ? 1 : -1;
+
+	if (family == AF_INET) {
+		if (ntohl(key->addr.a4.s_addr) == INADDR_ANY)
+			return 0;
+		if (ntohl(addr->a4.s_addr) == INADDR_ANY)
+			return 0;
+		return ipv4_prefix_cmp(&key->addr.a4, &addr->a4, prefixlen);
+#if IS_ENABLED(CONFIG_IPV6)
+	} else {
+		if (ipv6_addr_any(&key->addr.a6) || ipv6_addr_any(&addr->a6))
+			return 0;
+		if (ipv6_prefix_equal(&key->addr.a6, &addr->a6, prefixlen))
+			return 0;
+		return memcmp(&key->addr.a6, &addr->a6, sizeof(addr->a6));
+#endif
+	}
+	return -1;
+}
+
+static int tcp_ao_key_cmp(const struct tcp_ao_key *key, int l3index,
+			  const union tcp_ao_addr *addr, u8 prefixlen,
+			  int family, int sndid, int rcvid)
+{
+#if IS_ENABLED(CONFIG_IPV6)
+	if (family == AF_INET6 && ipv6_addr_v4mapped(&addr->a6)) {
+		__be32 addr4 = addr->a6.s6_addr32[3];
+
+		return __tcp_ao_key_cmp(key, l3index,
+					(union tcp_ao_addr *)&addr4,
+					prefixlen, AF_INET, sndid, rcvid);
+	}
+#endif
+	return __tcp_ao_key_cmp(key, l3index, addr,
+				prefixlen, family, sndid, rcvid);
+}
+
+static struct tcp_ao_key *__tcp_ao_do_lookup(const struct sock *sk, int l3index,
+		const union tcp_ao_addr *addr, int family, u8 prefix,
+		int sndid, int rcvid)
+{
+	struct tcp_ao_key *key;
+	struct tcp_ao_info *ao;
+
+	if (!static_branch_unlikely(&tcp_ao_needed.key))
+		return NULL;
+
+	ao = rcu_dereference_check(tcp_sk(sk)->ao_info,
+				   lockdep_sock_is_held(sk));
+	if (!ao)
+		return NULL;
+
+	hlist_for_each_entry_rcu(key, &ao->head, node) {
+		u8 prefixlen = min(prefix, key->prefixlen);
+
+		if (!tcp_ao_key_cmp(key, l3index, addr, prefixlen,
+				    family, sndid, rcvid))
+			return key;
+	}
+	return NULL;
+}
+
+struct tcp_ao_key *tcp_ao_do_lookup(const struct sock *sk, int l3index,
+				    const union tcp_ao_addr *addr,
+				    int family, int sndid, int rcvid)
+{
+	return __tcp_ao_do_lookup(sk, l3index, addr, family, U8_MAX, sndid, rcvid);
+}
+
+static struct tcp_ao_info *tcp_ao_alloc_info(gfp_t flags)
+{
+	struct tcp_ao_info *ao;
+
+	ao = kzalloc(sizeof(*ao), flags);
+	if (!ao)
+		return NULL;
+	INIT_HLIST_HEAD(&ao->head);
+	refcount_set(&ao->refcnt, 1);
+
+	return ao;
+}
+
+static void tcp_ao_link_mkt(struct tcp_ao_info *ao, struct tcp_ao_key *mkt)
+{
+	hlist_add_head_rcu(&mkt->node, &ao->head);
+}
+
+static struct tcp_ao_key *tcp_ao_copy_key(struct sock *sk,
+					  struct tcp_ao_key *key)
+{
+	struct tcp_ao_key *new_key;
+
+	new_key = sock_kmalloc(sk, tcp_ao_sizeof_key(key),
+			       GFP_ATOMIC);
+	if (!new_key)
+		return NULL;
+
+	*new_key = *key;
+	INIT_HLIST_NODE(&new_key->node);
+	tcp_sigpool_get(new_key->tcp_sigpool_id);
+	atomic64_set(&new_key->pkt_good, 0);
+	atomic64_set(&new_key->pkt_bad, 0);
+
+	return new_key;
+}
+
+static void tcp_ao_key_free_rcu(struct rcu_head *head)
+{
+	struct tcp_ao_key *key = container_of(head, struct tcp_ao_key, rcu);
+
+	tcp_sigpool_release(key->tcp_sigpool_id);
+	kfree_sensitive(key);
+}
+
+void tcp_ao_destroy_sock(struct sock *sk, bool twsk)
+{
+	struct tcp_ao_info *ao;
+	struct tcp_ao_key *key;
+	struct hlist_node *n;
+
+	if (twsk) {
+		ao = rcu_dereference_protected(tcp_twsk(sk)->ao_info, 1);
+		tcp_twsk(sk)->ao_info = NULL;
+	} else {
+		ao = rcu_dereference_protected(tcp_sk(sk)->ao_info, 1);
+		tcp_sk(sk)->ao_info = NULL;
+	}
+
+	if (!ao || !refcount_dec_and_test(&ao->refcnt))
+		return;
+
+	hlist_for_each_entry_safe(key, n, &ao->head, node) {
+		hlist_del_rcu(&key->node);
+		if (!twsk)
+			atomic_sub(tcp_ao_sizeof_key(key), &sk->sk_omem_alloc);
+		call_rcu(&key->rcu, tcp_ao_key_free_rcu);
+	}
+
+	kfree_rcu(ao, rcu);
+	static_branch_slow_dec_deferred(&tcp_ao_needed);
+}
+
+void tcp_ao_time_wait(struct tcp_timewait_sock *tcptw, struct tcp_sock *tp)
+{
+	struct tcp_ao_info *ao_info = rcu_dereference_protected(tp->ao_info, 1);
+
+	if (ao_info) {
+		struct tcp_ao_key *key;
+		struct hlist_node *n;
+		int omem = 0;
+
+		hlist_for_each_entry_safe(key, n, &ao_info->head, node) {
+			omem += tcp_ao_sizeof_key(key);
+		}
+
+		refcount_inc(&ao_info->refcnt);
+		atomic_sub(omem, &(((struct sock *)tp)->sk_omem_alloc));
+		rcu_assign_pointer(tcptw->ao_info, ao_info);
+	} else {
+		tcptw->ao_info = NULL;
+	}
+}
+
+/* 4 tuple and ISNs are expected in NBO */
+static int tcp_v4_ao_calc_key(struct tcp_ao_key *mkt, u8 *key,
+			      __be32 saddr, __be32 daddr,
+			      __be16 sport, __be16 dport,
+			      __be32 sisn,  __be32 disn)
+{
+	/* See RFC5926 3.1.1 */
+	struct kdf_input_block {
+		u8                      counter;
+		u8                      label[6];
+		struct tcp4_ao_context	ctx;
+		__be16                  outlen;
+	} __packed * tmp;
+	struct tcp_sigpool hp;
+	int err;
+
+	err = tcp_sigpool_start(mkt->tcp_sigpool_id, &hp);
+	if (err)
+		return err;
+
+	tmp = hp.scratch;
+	tmp->counter	= 1;
+	memcpy(tmp->label, "TCP-AO", 6);
+	tmp->ctx.saddr	= saddr;
+	tmp->ctx.daddr	= daddr;
+	tmp->ctx.sport	= sport;
+	tmp->ctx.dport	= dport;
+	tmp->ctx.sisn	= sisn;
+	tmp->ctx.disn	= disn;
+	tmp->outlen	= htons(tcp_ao_digest_size(mkt) * 8); /* in bits */
+
+	err = tcp_ao_calc_traffic_key(mkt, key, tmp, sizeof(*tmp), &hp);
+	tcp_sigpool_end(&hp);
+
+	return err;
+}
+
+int tcp_v4_ao_calc_key_sk(struct tcp_ao_key *mkt, u8 *key,
+			  const struct sock *sk,
+			  __be32 sisn, __be32 disn, bool send)
+{
+	if (send)
+		return tcp_v4_ao_calc_key(mkt, key, sk->sk_rcv_saddr,
+					  sk->sk_daddr, htons(sk->sk_num),
+					  sk->sk_dport, sisn, disn);
+	else
+		return tcp_v4_ao_calc_key(mkt, key, sk->sk_daddr,
+					  sk->sk_rcv_saddr, sk->sk_dport,
+					  htons(sk->sk_num), disn, sisn);
+}
+
+static int tcp_ao_calc_key_sk(struct tcp_ao_key *mkt, u8 *key,
+			      const struct sock *sk,
+			      __be32 sisn, __be32 disn, bool send)
+{
+	if (mkt->family == AF_INET)
+		return tcp_v4_ao_calc_key_sk(mkt, key, sk, sisn, disn, send);
+#if IS_ENABLED(CONFIG_IPV6)
+	else if (mkt->family == AF_INET6)
+		return tcp_v6_ao_calc_key_sk(mkt, key, sk, sisn, disn, send);
+#endif
+	else
+		return -EOPNOTSUPP;
+}
+
+int tcp_v4_ao_calc_key_rsk(struct tcp_ao_key *mkt, u8 *key,
+			   struct request_sock *req)
+{
+	struct inet_request_sock *ireq = inet_rsk(req);
+
+	return tcp_v4_ao_calc_key(mkt, key,
+				  ireq->ir_loc_addr, ireq->ir_rmt_addr,
+				  htons(ireq->ir_num), ireq->ir_rmt_port,
+				  htonl(tcp_rsk(req)->snt_isn),
+				  htonl(tcp_rsk(req)->rcv_isn));
+}
+
+static int tcp_v4_ao_calc_key_skb(struct tcp_ao_key *mkt, u8 *key,
+				  const struct sk_buff *skb,
+				  __be32 sisn, __be32 disn)
+{
+	const struct iphdr *iph = ip_hdr(skb);
+	const struct tcphdr *th = tcp_hdr(skb);
+
+	return tcp_v4_ao_calc_key(mkt, key, iph->saddr, iph->daddr,
+				  th->source, th->dest, sisn, disn);
+}
+
+static int tcp_ao_calc_key_skb(struct tcp_ao_key *mkt, u8 *key,
+			       const struct sk_buff *skb,
+			       __be32 sisn, __be32 disn, int family)
+{
+	if (family == AF_INET)
+		return tcp_v4_ao_calc_key_skb(mkt, key, skb, sisn, disn);
+#if IS_ENABLED(CONFIG_IPV6)
+	else if (family == AF_INET6)
+		return tcp_v6_ao_calc_key_skb(mkt, key, skb, sisn, disn);
+#endif
+	return -EAFNOSUPPORT;
+}
+
+static int tcp_v4_ao_hash_pseudoheader(struct tcp_sigpool *hp,
+				       __be32 daddr, __be32 saddr,
+				       int nbytes)
+{
+	struct tcp4_pseudohdr *bp;
+	struct scatterlist sg;
+
+	bp = hp->scratch;
+	bp->saddr = saddr;
+	bp->daddr = daddr;
+	bp->pad = 0;
+	bp->protocol = IPPROTO_TCP;
+	bp->len = cpu_to_be16(nbytes);
+
+	sg_init_one(&sg, bp, sizeof(*bp));
+	ahash_request_set_crypt(hp->req, &sg, NULL, sizeof(*bp));
+	return crypto_ahash_update(hp->req);
+}
+
+static int tcp_ao_hash_pseudoheader(unsigned short int family,
+				    const struct sock *sk,
+				    const struct sk_buff *skb,
+				    struct tcp_sigpool *hp, int nbytes)
+{
+	const struct tcphdr *th = tcp_hdr(skb);
+
+	/* TODO: Can we rely on checksum being zero to mean outbound pkt? */
+	if (!th->check) {
+		if (family == AF_INET)
+			return tcp_v4_ao_hash_pseudoheader(hp, sk->sk_daddr,
+					sk->sk_rcv_saddr, skb->len);
+#if IS_ENABLED(CONFIG_IPV6)
+		else if (family == AF_INET6)
+			return tcp_v6_ao_hash_pseudoheader(hp, &sk->sk_v6_daddr,
+					&sk->sk_v6_rcv_saddr, skb->len);
+#endif
+		else
+			return -EAFNOSUPPORT;
+	}
+
+	if (family == AF_INET) {
+		const struct iphdr *iph = ip_hdr(skb);
+
+		return tcp_v4_ao_hash_pseudoheader(hp, iph->daddr,
+				iph->saddr, skb->len);
+#if IS_ENABLED(CONFIG_IPV6)
+	} else if (family == AF_INET6) {
+		const struct ipv6hdr *iph = ipv6_hdr(skb);
+
+		return tcp_v6_ao_hash_pseudoheader(hp, &iph->daddr,
+				&iph->saddr, skb->len);
+#endif
+	}
+	return -EAFNOSUPPORT;
+}
+
+u32 tcp_ao_compute_sne(u32 next_sne, u32 next_seq, u32 seq)
+{
+	u32 sne = next_sne;
+
+	if (before(seq, next_seq)) {
+		if (seq > next_seq)
+			sne--;
+	} else {
+		if (seq < next_seq)
+			sne++;
+	}
+
+	return sne;
+}
+
+/* tcp_ao_hash_sne(struct tcp_sigpool *hp)
+ * @hp	- used for hashing
+ * @sne - sne value
+ */
+static int tcp_ao_hash_sne(struct tcp_sigpool *hp, u32 sne)
+{
+	struct scatterlist sg;
+	__be32 *bp;
+
+	bp = (__be32 *)hp->scratch;
+	*bp = htonl(sne);
+
+	sg_init_one(&sg, bp, sizeof(*bp));
+	ahash_request_set_crypt(hp->req, &sg, NULL, sizeof(*bp));
+	return crypto_ahash_update(hp->req);
+}
+
+static int tcp_ao_hash_header(struct tcp_sigpool *hp,
+			      const struct tcphdr *th,
+			      bool exclude_options, u8 *hash,
+			      int hash_offset, int hash_len)
+{
+	int err, len = th->doff << 2;
+	struct scatterlist sg;
+	u8 *hdr = hp->scratch;
+
+	/* We are not allowed to change tcphdr, make a local copy */
+	if (exclude_options) {
+		len = sizeof(*th) + sizeof(struct tcp_ao_hdr) + hash_len;
+		memcpy(hdr, th, sizeof(*th));
+		memcpy(hdr + sizeof(*th),
+		       (u8 *)th + hash_offset - sizeof(struct tcp_ao_hdr),
+		       sizeof(struct tcp_ao_hdr));
+		memset(hdr + sizeof(*th) + sizeof(struct tcp_ao_hdr),
+		       0, hash_len);
+		((struct tcphdr *)hdr)->check = 0;
+	} else {
+		len = th->doff << 2;
+		memcpy(hdr, th, len);
+		/* zero out tcp-ao hash */
+		((struct tcphdr *)hdr)->check = 0;
+		memset(hdr + hash_offset, 0, hash_len);
+	}
+
+	sg_init_one(&sg, hdr, len);
+	ahash_request_set_crypt(hp->req, &sg, NULL, len);
+	err = crypto_ahash_update(hp->req);
+	WARN_ON_ONCE(err != 0);
+	return err;
+}
+
+int tcp_ao_hash_hdr(unsigned short int family, char *ao_hash,
+		    struct tcp_ao_key *key, const u8 *tkey,
+		    const union tcp_ao_addr *daddr,
+		    const union tcp_ao_addr *saddr,
+		    const struct tcphdr *th, u32 sne)
+{
+	int tkey_len = tcp_ao_digest_size(key);
+	int hash_offset = ao_hash - (char *)th;
+	struct tcp_sigpool hp;
+	void *hash_buf = NULL;
+
+	hash_buf = kmalloc(tkey_len, GFP_ATOMIC);
+	if (!hash_buf)
+		goto clear_hash_noput;
+
+	if (tcp_sigpool_start(key->tcp_sigpool_id, &hp))
+		goto clear_hash_noput;
+
+	if (crypto_ahash_setkey(crypto_ahash_reqtfm(hp.req), tkey, tkey_len))
+		goto clear_hash;
+
+	if (crypto_ahash_init(hp.req))
+		goto clear_hash;
+
+	if (tcp_ao_hash_sne(&hp, sne))
+		goto clear_hash;
+	if (family == AF_INET) {
+		if (tcp_v4_ao_hash_pseudoheader(&hp, daddr->a4.s_addr,
+						saddr->a4.s_addr, th->doff * 4))
+			goto clear_hash;
+#if IS_ENABLED(CONFIG_IPV6)
+	} else if (family == AF_INET6) {
+		if (tcp_v6_ao_hash_pseudoheader(&hp, &daddr->a6,
+						&saddr->a6, th->doff * 4))
+			goto clear_hash;
+#endif
+	} else {
+		WARN_ON_ONCE(1);
+		goto clear_hash;
+	}
+	if (tcp_ao_hash_header(&hp, th,
+			       !!(key->keyflags & TCP_AO_KEYF_EXCLUDE_OPT),
+			       ao_hash, hash_offset, tcp_ao_maclen(key)))
+		goto clear_hash;
+	ahash_request_set_crypt(hp.req, NULL, hash_buf, 0);
+	if (crypto_ahash_final(hp.req))
+		goto clear_hash;
+
+	memcpy(ao_hash, hash_buf, tcp_ao_maclen(key));
+	tcp_sigpool_end(&hp);
+	kfree(hash_buf);
+	return 0;
+
+clear_hash:
+	tcp_sigpool_end(&hp);
+clear_hash_noput:
+	memset(ao_hash, 0, tcp_ao_maclen(key));
+	kfree(hash_buf);
+	return 1;
+}
+
+int tcp_ao_hash_skb(unsigned short int family,
+		    char *ao_hash, struct tcp_ao_key *key,
+		    const struct sock *sk, const struct sk_buff *skb,
+		    const u8 *tkey, int hash_offset, u32 sne)
+{
+	const struct tcphdr *th = tcp_hdr(skb);
+	int tkey_len = tcp_ao_digest_size(key);
+	struct tcp_sigpool hp;
+	void *hash_buf = NULL;
+
+	hash_buf = kmalloc(tkey_len, GFP_ATOMIC);
+	if (!hash_buf)
+		goto clear_hash_noput;
+
+	if (tcp_sigpool_start(key->tcp_sigpool_id, &hp))
+		goto clear_hash_noput;
+
+	if (crypto_ahash_setkey(crypto_ahash_reqtfm(hp.req), tkey, tkey_len))
+		goto clear_hash;
+
+	/* For now use sha1 by default. Depends on alg in tcp_ao_key */
+	if (crypto_ahash_init(hp.req))
+		goto clear_hash;
+
+	if (tcp_ao_hash_sne(&hp, sne))
+		goto clear_hash;
+	if (tcp_ao_hash_pseudoheader(family, sk, skb, &hp, skb->len))
+		goto clear_hash;
+	if (tcp_ao_hash_header(&hp, th,
+			       !!(key->keyflags & TCP_AO_KEYF_EXCLUDE_OPT),
+			       ao_hash, hash_offset, tcp_ao_maclen(key)))
+		goto clear_hash;
+	if (tcp_sigpool_hash_skb_data(&hp, skb, th->doff << 2))
+		goto clear_hash;
+	ahash_request_set_crypt(hp.req, NULL, hash_buf, 0);
+	if (crypto_ahash_final(hp.req))
+		goto clear_hash;
+
+	memcpy(ao_hash, hash_buf, tcp_ao_maclen(key));
+	tcp_sigpool_end(&hp);
+	kfree(hash_buf);
+	return 0;
+
+clear_hash:
+	tcp_sigpool_end(&hp);
+clear_hash_noput:
+	memset(ao_hash, 0, tcp_ao_maclen(key));
+	kfree(hash_buf);
+	return 1;
+}
+
+int tcp_v4_ao_hash_skb(char *ao_hash, struct tcp_ao_key *key,
+		       const struct sock *sk, const struct sk_buff *skb,
+		       const u8 *tkey, int hash_offset, u32 sne)
+{
+	return tcp_ao_hash_skb(AF_INET, ao_hash, key, sk, skb,
+			       tkey, hash_offset, sne);
+}
+
+int tcp_v4_ao_synack_hash(char *ao_hash, struct tcp_ao_key *ao_key,
+			  struct request_sock *req, const struct sk_buff *skb,
+			  int hash_offset, u32 sne)
+{
+	void *hash_buf = NULL;
+	int err;
+
+	hash_buf = kmalloc(tcp_ao_digest_size(ao_key), GFP_ATOMIC);
+	if (!hash_buf)
+		return -ENOMEM;
+
+	err = tcp_v4_ao_calc_key_rsk(ao_key, hash_buf, req);
+	if (err)
+		goto out;
+
+	err = tcp_ao_hash_skb(AF_INET, ao_hash, ao_key, req_to_sk(req), skb,
+			      hash_buf, hash_offset, sne);
+out:
+	kfree(hash_buf);
+	return err;
+}
+
+struct tcp_ao_key *tcp_v4_ao_lookup_rsk(const struct sock *sk,
+					struct request_sock *req,
+					int sndid, int rcvid)
+{
+	struct inet_request_sock *ireq = inet_rsk(req);
+	union tcp_ao_addr *addr = (union tcp_ao_addr *)&ireq->ir_rmt_addr;
+	int l3index;
+
+	l3index = l3mdev_master_ifindex_by_index(sock_net(sk), ireq->ir_iif);
+	return tcp_ao_do_lookup(sk, l3index, addr, AF_INET, sndid, rcvid);
+}
+
+struct tcp_ao_key *tcp_v4_ao_lookup(const struct sock *sk, struct sock *addr_sk,
+				    int sndid, int rcvid)
+{
+	int l3index = l3mdev_master_ifindex_by_index(sock_net(sk),
+						     addr_sk->sk_bound_dev_if);
+	union tcp_ao_addr *addr = (union tcp_ao_addr *)&addr_sk->sk_daddr;
+
+	return tcp_ao_do_lookup(sk, l3index, addr, AF_INET, sndid, rcvid);
+}
+
+int tcp_ao_prepare_reset(const struct sock *sk, struct sk_buff *skb,
+			 const struct tcp_ao_hdr *aoh, int l3index, u32 seq,
+			 struct tcp_ao_key **key, char **traffic_key,
+			 bool *allocated_traffic_key, u8 *keyid, u32 *sne)
+{
+	const struct tcphdr *th = tcp_hdr(skb);
+	struct tcp_ao_info *ao_info;
+
+	*allocated_traffic_key = false;
+	/* If there's no socket - than initial sisn/disn are unknown.
+	 * Drop the segment. RFC5925 (7.7) advises to require graceful
+	 * restart [RFC4724]. Alternatively, the RFC5925 advises to
+	 * save/restore traffic keys before/after reboot.
+	 * Linux TCP-AO support provides TCP_AO_ADD_KEY and TCP_AO_REPAIR
+	 * options to restore a socket post-reboot.
+	 */
+	if (!sk)
+		return -ENOTCONN;
+
+	if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_NEW_SYN_RECV)) {
+		unsigned int family = READ_ONCE(sk->sk_family);
+		union tcp_ao_addr *addr;
+		__be32 disn, sisn;
+
+		if (sk->sk_state == TCP_NEW_SYN_RECV) {
+			struct request_sock *req = inet_reqsk(sk);
+
+			sisn = htonl(tcp_rsk(req)->rcv_isn);
+			disn = htonl(tcp_rsk(req)->snt_isn);
+			*sne = tcp_ao_compute_sne(0, tcp_rsk(req)->snt_isn, seq);
+		} else {
+			sisn = th->seq;
+			disn = 0;
+		}
+		if (IS_ENABLED(CONFIG_IPV6) && family == AF_INET6)
+			addr = (union tcp_md5_addr *)&ipv6_hdr(skb)->saddr;
+		else
+			addr = (union tcp_md5_addr *)&ip_hdr(skb)->saddr;
+#if IS_ENABLED(CONFIG_IPV6)
+		if (family == AF_INET6 && ipv6_addr_v4mapped(&sk->sk_v6_daddr))
+			family = AF_INET;
+#endif
+
+		sk = sk_const_to_full_sk(sk);
+		ao_info = rcu_dereference(tcp_sk(sk)->ao_info);
+		if (!ao_info)
+			return -ENOENT;
+		*key = tcp_ao_do_lookup(sk, l3index, addr, family,
+					-1, aoh->rnext_keyid);
+		if (!*key)
+			return -ENOENT;
+		*traffic_key = kmalloc(tcp_ao_digest_size(*key), GFP_ATOMIC);
+		if (!*traffic_key)
+			return -ENOMEM;
+		*allocated_traffic_key = true;
+		if (tcp_ao_calc_key_skb(*key, *traffic_key, skb,
+					sisn, disn, family))
+			return -1;
+		*keyid = (*key)->rcvid;
+	} else {
+		struct tcp_ao_key *rnext_key;
+		u32 snd_basis;
+
+		if (sk->sk_state == TCP_TIME_WAIT) {
+			ao_info = rcu_dereference(tcp_twsk(sk)->ao_info);
+			snd_basis = tcp_twsk(sk)->tw_snd_nxt;
+		} else {
+			ao_info = rcu_dereference(tcp_sk(sk)->ao_info);
+			snd_basis = tcp_sk(sk)->snd_una;
+		}
+		if (!ao_info)
+			return -ENOENT;
+
+		*key = tcp_ao_established_key(ao_info, aoh->rnext_keyid, -1);
+		if (!*key)
+			return -ENOENT;
+		*traffic_key = snd_other_key(*key);
+		rnext_key = READ_ONCE(ao_info->rnext_key);
+		*keyid = rnext_key->rcvid;
+		*sne = tcp_ao_compute_sne(READ_ONCE(ao_info->snd_sne),
+					  snd_basis, seq);
+	}
+	return 0;
+}
+
+int tcp_ao_transmit_skb(struct sock *sk, struct sk_buff *skb,
+			struct tcp_ao_key *key, struct tcphdr *th,
+			__u8 *hash_location)
+{
+	struct tcp_skb_cb *tcb = TCP_SKB_CB(skb);
+	struct tcp_sock *tp = tcp_sk(sk);
+	struct tcp_ao_info *ao;
+	void *tkey_buf = NULL;
+	u8 *traffic_key;
+	u32 sne;
+
+	ao = rcu_dereference_protected(tcp_sk(sk)->ao_info,
+				       lockdep_sock_is_held(sk));
+	traffic_key = snd_other_key(key);
+	if (unlikely(tcb->tcp_flags & TCPHDR_SYN)) {
+		__be32 disn;
+
+		if (!(tcb->tcp_flags & TCPHDR_ACK)) {
+			disn = 0;
+			tkey_buf = kmalloc(tcp_ao_digest_size(key), GFP_ATOMIC);
+			if (!tkey_buf)
+				return -ENOMEM;
+			traffic_key = tkey_buf;
+		} else {
+			disn = ao->risn;
+		}
+		tp->af_specific->ao_calc_key_sk(key, traffic_key,
+						sk, ao->lisn, disn, true);
+	}
+	sne = tcp_ao_compute_sne(READ_ONCE(ao->snd_sne), READ_ONCE(tp->snd_una),
+				 ntohl(th->seq));
+	tp->af_specific->calc_ao_hash(hash_location, key, sk, skb, traffic_key,
+				      hash_location - (u8 *)th, sne);
+	kfree(tkey_buf);
+	return 0;
+}
+
+static struct tcp_ao_key *tcp_ao_inbound_lookup(unsigned short int family,
+		const struct sock *sk, const struct sk_buff *skb,
+		int sndid, int rcvid, int l3index)
+{
+	if (family == AF_INET) {
+		const struct iphdr *iph = ip_hdr(skb);
+
+		return tcp_ao_do_lookup(sk, l3index,
+					(union tcp_ao_addr *)&iph->saddr,
+					AF_INET, sndid, rcvid);
+	} else {
+		const struct ipv6hdr *iph = ipv6_hdr(skb);
+
+		return tcp_ao_do_lookup(sk, l3index,
+					(union tcp_ao_addr *)&iph->saddr,
+					AF_INET6, sndid, rcvid);
+	}
+}
+
+void tcp_ao_syncookie(struct sock *sk, const struct sk_buff *skb,
+		      struct tcp_request_sock *treq,
+		      unsigned short int family, int l3index)
+{
+	const struct tcphdr *th = tcp_hdr(skb);
+	const struct tcp_ao_hdr *aoh;
+	struct tcp_ao_key *key;
+
+	treq->used_tcp_ao = false;
+
+	if (tcp_parse_auth_options(th, NULL, &aoh) || !aoh)
+		return;
+
+	key = tcp_ao_inbound_lookup(family, sk, skb, -1, aoh->keyid, l3index);
+	if (!key)
+		/* Key not found, continue without TCP-AO */
+		return;
+
+	treq->ao_rcv_next = aoh->keyid;
+	treq->ao_keyid = aoh->rnext_keyid;
+	treq->used_tcp_ao = true;
+}
+
+static enum skb_drop_reason
+tcp_ao_verify_hash(const struct sock *sk, const struct sk_buff *skb,
+		   unsigned short int family, struct tcp_ao_info *info,
+		   const struct tcp_ao_hdr *aoh, struct tcp_ao_key *key,
+		   u8 *traffic_key, u8 *phash, u32 sne, int l3index)
+{
+	u8 maclen = aoh->length - sizeof(struct tcp_ao_hdr);
+	const struct tcphdr *th = tcp_hdr(skb);
+	void *hash_buf = NULL;
+
+	if (maclen != tcp_ao_maclen(key)) {
+		NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPAOBAD);
+		atomic64_inc(&info->counters.pkt_bad);
+		atomic64_inc(&key->pkt_bad);
+		tcp_hash_fail("AO hash wrong length", family, skb,
+			      "%u != %d L3index: %d", maclen,
+			      tcp_ao_maclen(key), l3index);
+		return SKB_DROP_REASON_TCP_AOFAILURE;
+	}
+
+	hash_buf = kmalloc(tcp_ao_digest_size(key), GFP_ATOMIC);
+	if (!hash_buf)
+		return SKB_DROP_REASON_NOT_SPECIFIED;
+
+	/* XXX: make it per-AF callback? */
+	tcp_ao_hash_skb(family, hash_buf, key, sk, skb, traffic_key,
+			(phash - (u8 *)th), sne);
+	if (memcmp(phash, hash_buf, maclen)) {
+		NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPAOBAD);
+		atomic64_inc(&info->counters.pkt_bad);
+		atomic64_inc(&key->pkt_bad);
+		tcp_hash_fail("AO hash mismatch", family, skb,
+			      "L3index: %d", l3index);
+		kfree(hash_buf);
+		return SKB_DROP_REASON_TCP_AOFAILURE;
+	}
+	NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPAOGOOD);
+	atomic64_inc(&info->counters.pkt_good);
+	atomic64_inc(&key->pkt_good);
+	kfree(hash_buf);
+	return SKB_NOT_DROPPED_YET;
+}
+
+enum skb_drop_reason
+tcp_inbound_ao_hash(struct sock *sk, const struct sk_buff *skb,
+		    unsigned short int family, const struct request_sock *req,
+		    int l3index, const struct tcp_ao_hdr *aoh)
+{
+	const struct tcphdr *th = tcp_hdr(skb);
+	u8 *phash = (u8 *)(aoh + 1); /* hash goes just after the header */
+	struct tcp_ao_info *info;
+	enum skb_drop_reason ret;
+	struct tcp_ao_key *key;
+	__be32 sisn, disn;
+	u8 *traffic_key;
+	u32 sne = 0;
+
+	info = rcu_dereference(tcp_sk(sk)->ao_info);
+	if (!info) {
+		NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPAOKEYNOTFOUND);
+		tcp_hash_fail("AO key not found", family, skb,
+			      "keyid: %u L3index: %d", aoh->keyid, l3index);
+		return SKB_DROP_REASON_TCP_AOUNEXPECTED;
+	}
+
+	if (unlikely(th->syn)) {
+		sisn = th->seq;
+		disn = 0;
+	}
+
+	/* Fast-path */
+	if (likely((1 << sk->sk_state) & TCP_AO_ESTABLISHED)) {
+		enum skb_drop_reason err;
+		struct tcp_ao_key *current_key;
+
+		/* Check if this socket's rnext_key matches the keyid in the
+		 * packet. If not we lookup the key based on the keyid
+		 * matching the rcvid in the mkt.
+		 */
+		key = READ_ONCE(info->rnext_key);
+		if (key->rcvid != aoh->keyid) {
+			key = tcp_ao_established_key(info, -1, aoh->keyid);
+			if (!key)
+				goto key_not_found;
+		}
+
+		/* Delayed retransmitted SYN */
+		if (unlikely(th->syn && !th->ack))
+			goto verify_hash;
+
+		sne = tcp_ao_compute_sne(info->rcv_sne, tcp_sk(sk)->rcv_nxt,
+					 ntohl(th->seq));
+		/* Established socket, traffic key are cached */
+		traffic_key = rcv_other_key(key);
+		err = tcp_ao_verify_hash(sk, skb, family, info, aoh, key,
+					 traffic_key, phash, sne, l3index);
+		if (err)
+			return err;
+		current_key = READ_ONCE(info->current_key);
+		/* Key rotation: the peer asks us to use new key (RNext) */
+		if (unlikely(aoh->rnext_keyid != current_key->sndid)) {
+			/* If the key is not found we do nothing. */
+			key = tcp_ao_established_key(info, aoh->rnext_keyid, -1);
+			if (key)
+				/* pairs with tcp_ao_del_cmd */
+				WRITE_ONCE(info->current_key, key);
+		}
+		return SKB_NOT_DROPPED_YET;
+	}
+
+	/* Lookup key based on peer address and keyid.
+	 * current_key and rnext_key must not be used on tcp listen
+	 * sockets as otherwise:
+	 * - request sockets would race on those key pointers
+	 * - tcp_ao_del_cmd() allows async key removal
+	 */
+	key = tcp_ao_inbound_lookup(family, sk, skb, -1, aoh->keyid, l3index);
+	if (!key)
+		goto key_not_found;
+
+	if (th->syn && !th->ack)
+		goto verify_hash;
+
+	if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_NEW_SYN_RECV)) {
+		/* Make the initial syn the likely case here */
+		if (unlikely(req)) {
+			sne = tcp_ao_compute_sne(0, tcp_rsk(req)->rcv_isn,
+						 ntohl(th->seq));
+			sisn = htonl(tcp_rsk(req)->rcv_isn);
+			disn = htonl(tcp_rsk(req)->snt_isn);
+		} else if (unlikely(th->ack && !th->syn)) {
+			/* Possible syncookie packet */
+			sisn = htonl(ntohl(th->seq) - 1);
+			disn = htonl(ntohl(th->ack_seq) - 1);
+			sne = tcp_ao_compute_sne(0, ntohl(sisn),
+						 ntohl(th->seq));
+		} else if (unlikely(!th->syn)) {
+			/* no way to figure out initial sisn/disn - drop */
+			return SKB_DROP_REASON_TCP_FLAGS;
+		}
+	} else if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV)) {
+		disn = info->lisn;
+		if (th->syn || th->rst)
+			sisn = th->seq;
+		else
+			sisn = info->risn;
+	} else {
+		WARN_ONCE(1, "TCP-AO: Unexpected sk_state %d", sk->sk_state);
+		return SKB_DROP_REASON_TCP_AOFAILURE;
+	}
+verify_hash:
+	traffic_key = kmalloc(tcp_ao_digest_size(key), GFP_ATOMIC);
+	if (!traffic_key)
+		return SKB_DROP_REASON_NOT_SPECIFIED;
+	tcp_ao_calc_key_skb(key, traffic_key, skb, sisn, disn, family);
+	ret = tcp_ao_verify_hash(sk, skb, family, info, aoh, key,
+				 traffic_key, phash, sne, l3index);
+	kfree(traffic_key);
+	return ret;
+
+key_not_found:
+	NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPAOKEYNOTFOUND);
+	atomic64_inc(&info->counters.key_not_found);
+	tcp_hash_fail("Requested by the peer AO key id not found",
+		      family, skb, "L3index: %d", l3index);
+	return SKB_DROP_REASON_TCP_AOKEYNOTFOUND;
+}
+
+static int tcp_ao_cache_traffic_keys(const struct sock *sk,
+				     struct tcp_ao_info *ao,
+				     struct tcp_ao_key *ao_key)
+{
+	u8 *traffic_key = snd_other_key(ao_key);
+	int ret;
+
+	ret = tcp_ao_calc_key_sk(ao_key, traffic_key, sk,
+				 ao->lisn, ao->risn, true);
+	if (ret)
+		return ret;
+
+	traffic_key = rcv_other_key(ao_key);
+	ret = tcp_ao_calc_key_sk(ao_key, traffic_key, sk,
+				 ao->lisn, ao->risn, false);
+	return ret;
+}
+
+void tcp_ao_connect_init(struct sock *sk)
+{
+	struct tcp_sock *tp = tcp_sk(sk);
+	struct tcp_ao_info *ao_info;
+	union tcp_ao_addr *addr;
+	struct tcp_ao_key *key;
+	int family, l3index;
+
+	ao_info = rcu_dereference_protected(tp->ao_info,
+					    lockdep_sock_is_held(sk));
+	if (!ao_info)
+		return;
+
+	/* Remove all keys that don't match the peer */
+	family = sk->sk_family;
+	if (family == AF_INET)
+		addr = (union tcp_ao_addr *)&sk->sk_daddr;
+#if IS_ENABLED(CONFIG_IPV6)
+	else if (family == AF_INET6)
+		addr = (union tcp_ao_addr *)&sk->sk_v6_daddr;
+#endif
+	else
+		return;
+	l3index = l3mdev_master_ifindex_by_index(sock_net(sk),
+						 sk->sk_bound_dev_if);
+
+	hlist_for_each_entry_rcu(key, &ao_info->head, node) {
+		if (!tcp_ao_key_cmp(key, l3index, addr, key->prefixlen, family, -1, -1))
+			continue;
+
+		if (key == ao_info->current_key)
+			ao_info->current_key = NULL;
+		if (key == ao_info->rnext_key)
+			ao_info->rnext_key = NULL;
+		hlist_del_rcu(&key->node);
+		atomic_sub(tcp_ao_sizeof_key(key), &sk->sk_omem_alloc);
+		call_rcu(&key->rcu, tcp_ao_key_free_rcu);
+	}
+
+	key = tp->af_specific->ao_lookup(sk, sk, -1, -1);
+	if (key) {
+		/* if current_key or rnext_key were not provided,
+		 * use the first key matching the peer
+		 */
+		if (!ao_info->current_key)
+			ao_info->current_key = key;
+		if (!ao_info->rnext_key)
+			ao_info->rnext_key = key;
+		tp->tcp_header_len += tcp_ao_len_aligned(key);
+
+		ao_info->lisn = htonl(tp->write_seq);
+		ao_info->snd_sne = 0;
+	} else {
+		/* Can't happen: tcp_connect() verifies that there's
+		 * at least one tcp-ao key that matches the remote peer.
+		 */
+		WARN_ON_ONCE(1);
+		rcu_assign_pointer(tp->ao_info, NULL);
+		kfree(ao_info);
+	}
+}
+
+void tcp_ao_established(struct sock *sk)
+{
+	struct tcp_ao_info *ao;
+	struct tcp_ao_key *key;
+
+	ao = rcu_dereference_protected(tcp_sk(sk)->ao_info,
+				       lockdep_sock_is_held(sk));
+	if (!ao)
+		return;
+
+	hlist_for_each_entry_rcu(key, &ao->head, node)
+		tcp_ao_cache_traffic_keys(sk, ao, key);
+}
+
+void tcp_ao_finish_connect(struct sock *sk, struct sk_buff *skb)
+{
+	struct tcp_ao_info *ao;
+	struct tcp_ao_key *key;
+
+	ao = rcu_dereference_protected(tcp_sk(sk)->ao_info,
+				       lockdep_sock_is_held(sk));
+	if (!ao)
+		return;
+
+	WRITE_ONCE(ao->risn, tcp_hdr(skb)->seq);
+	ao->rcv_sne = 0;
+
+	hlist_for_each_entry_rcu(key, &ao->head, node)
+		tcp_ao_cache_traffic_keys(sk, ao, key);
+}
+
+int tcp_ao_copy_all_matching(const struct sock *sk, struct sock *newsk,
+			     struct request_sock *req, struct sk_buff *skb,
+			     int family)
+{
+	struct tcp_ao_key *key, *new_key, *first_key;
+	struct tcp_ao_info *new_ao, *ao;
+	struct hlist_node *key_head;
+	int l3index, ret = -ENOMEM;
+	union tcp_ao_addr *addr;
+	bool match = false;
+
+	ao = rcu_dereference(tcp_sk(sk)->ao_info);
+	if (!ao)
+		return 0;
+
+	/* New socket without TCP-AO on it */
+	if (!tcp_rsk_used_ao(req))
+		return 0;
+
+	new_ao = tcp_ao_alloc_info(GFP_ATOMIC);
+	if (!new_ao)
+		return -ENOMEM;
+	new_ao->lisn = htonl(tcp_rsk(req)->snt_isn);
+	new_ao->risn = htonl(tcp_rsk(req)->rcv_isn);
+	new_ao->ao_required = ao->ao_required;
+	new_ao->accept_icmps = ao->accept_icmps;
+
+	if (family == AF_INET) {
+		addr = (union tcp_ao_addr *)&newsk->sk_daddr;
+#if IS_ENABLED(CONFIG_IPV6)
+	} else if (family == AF_INET6) {
+		addr = (union tcp_ao_addr *)&newsk->sk_v6_daddr;
+#endif
+	} else {
+		ret = -EAFNOSUPPORT;
+		goto free_ao;
+	}
+	l3index = l3mdev_master_ifindex_by_index(sock_net(newsk),
+						 newsk->sk_bound_dev_if);
+
+	hlist_for_each_entry_rcu(key, &ao->head, node) {
+		if (tcp_ao_key_cmp(key, l3index, addr, key->prefixlen, family, -1, -1))
+			continue;
+
+		new_key = tcp_ao_copy_key(newsk, key);
+		if (!new_key)
+			goto free_and_exit;
+
+		tcp_ao_cache_traffic_keys(newsk, new_ao, new_key);
+		tcp_ao_link_mkt(new_ao, new_key);
+		match = true;
+	}
+
+	if (!match) {
+		/* RFC5925 (7.4.1) specifies that the TCP-AO status
+		 * of a connection is determined on the initial SYN.
+		 * At this point the connection was TCP-AO enabled, so
+		 * it can't switch to being unsigned if peer's key
+		 * disappears on the listening socket.
+		 */
+		ret = -EKEYREJECTED;
+		goto free_and_exit;
+	}
+
+	if (!static_key_fast_inc_not_disabled(&tcp_ao_needed.key.key)) {
+		ret = -EUSERS;
+		goto free_and_exit;
+	}
+
+	key_head = rcu_dereference(hlist_first_rcu(&new_ao->head));
+	first_key = hlist_entry_safe(key_head, struct tcp_ao_key, node);
+
+	key = tcp_ao_established_key(new_ao, tcp_rsk(req)->ao_keyid, -1);
+	if (key)
+		new_ao->current_key = key;
+	else
+		new_ao->current_key = first_key;
+
+	/* set rnext_key */
+	key = tcp_ao_established_key(new_ao, -1, tcp_rsk(req)->ao_rcv_next);
+	if (key)
+		new_ao->rnext_key = key;
+	else
+		new_ao->rnext_key = first_key;
+
+	sk_gso_disable(newsk);
+	rcu_assign_pointer(tcp_sk(newsk)->ao_info, new_ao);
+
+	return 0;
+
+free_and_exit:
+	hlist_for_each_entry_safe(key, key_head, &new_ao->head, node) {
+		hlist_del(&key->node);
+		tcp_sigpool_release(key->tcp_sigpool_id);
+		atomic_sub(tcp_ao_sizeof_key(key), &newsk->sk_omem_alloc);
+		kfree_sensitive(key);
+	}
+free_ao:
+	kfree(new_ao);
+	return ret;
+}
+
+static bool tcp_ao_can_set_current_rnext(struct sock *sk)
+{
+	/* There aren't current/rnext keys on TCP_LISTEN sockets */
+	if (sk->sk_state == TCP_LISTEN)
+		return false;
+	return true;
+}
+
+static int tcp_ao_verify_ipv4(struct sock *sk, struct tcp_ao_add *cmd,
+			      union tcp_ao_addr **addr)
+{
+	struct sockaddr_in *sin = (struct sockaddr_in *)&cmd->addr;
+	struct inet_sock *inet = inet_sk(sk);
+
+	if (sin->sin_family != AF_INET)
+		return -EINVAL;
+
+	/* Currently matching is not performed on port (or port ranges) */
+	if (sin->sin_port != 0)
+		return -EINVAL;
+
+	/* Check prefix and trailing 0's in addr */
+	if (cmd->prefix != 0) {
+		__be32 mask;
+
+		if (ntohl(sin->sin_addr.s_addr) == INADDR_ANY)
+			return -EINVAL;
+		if (cmd->prefix > 32)
+			return -EINVAL;
+
+		mask = inet_make_mask(cmd->prefix);
+		if (sin->sin_addr.s_addr & ~mask)
+			return -EINVAL;
+
+		/* Check that MKT address is consistent with socket */
+		if (ntohl(inet->inet_daddr) != INADDR_ANY &&
+		    (inet->inet_daddr & mask) != sin->sin_addr.s_addr)
+			return -EINVAL;
+	} else {
+		if (ntohl(sin->sin_addr.s_addr) != INADDR_ANY)
+			return -EINVAL;
+	}
+
+	*addr = (union tcp_ao_addr *)&sin->sin_addr;
+	return 0;
+}
+
+static int tcp_ao_parse_crypto(struct tcp_ao_add *cmd, struct tcp_ao_key *key)
+{
+	unsigned int syn_tcp_option_space;
+	bool is_kdf_aes_128_cmac = false;
+	struct crypto_ahash *tfm;
+	struct tcp_sigpool hp;
+	void *tmp_key = NULL;
+	int err;
+
+	/* RFC5926, 3.1.1.2. KDF_AES_128_CMAC */
+	if (!strcmp("cmac(aes128)", cmd->alg_name)) {
+		strscpy(cmd->alg_name, "cmac(aes)", sizeof(cmd->alg_name));
+		is_kdf_aes_128_cmac = (cmd->keylen != 16);
+		tmp_key = kmalloc(cmd->keylen, GFP_KERNEL);
+		if (!tmp_key)
+			return -ENOMEM;
+	}
+
+	key->maclen = cmd->maclen ?: 12; /* 12 is the default in RFC5925 */
+
+	/* Check: maclen + tcp-ao header <= (MAX_TCP_OPTION_SPACE - mss
+	 *					- tstamp (including sackperm)
+	 *					- wscale),
+	 * see tcp_syn_options(), tcp_synack_options(), commit 33ad798c924b.
+	 *
+	 * In order to allow D-SACK with TCP-AO, the header size should be:
+	 * (MAX_TCP_OPTION_SPACE - TCPOLEN_TSTAMP_ALIGNED
+	 *			- TCPOLEN_SACK_BASE_ALIGNED
+	 *			- 2 * TCPOLEN_SACK_PERBLOCK) = 8 (maclen = 4),
+	 * see tcp_established_options().
+	 *
+	 * RFC5925, 2.2:
+	 * Typical MACs are 96-128 bits (12-16 bytes), but any length
+	 * that fits in the header of the segment being authenticated
+	 * is allowed.
+	 *
+	 * RFC5925, 7.6:
+	 * TCP-AO continues to consume 16 bytes in non-SYN segments,
+	 * leaving a total of 24 bytes for other options, of which
+	 * the timestamp consumes 10.  This leaves 14 bytes, of which 10
+	 * are used for a single SACK block. When two SACK blocks are used,
+	 * such as to handle D-SACK, a smaller TCP-AO MAC would be required
+	 * to make room for the additional SACK block (i.e., to leave 18
+	 * bytes for the D-SACK variant of the SACK option) [RFC2883].
+	 * Note that D-SACK is not supportable in TCP MD5 in the presence
+	 * of timestamps, because TCP MD5’s MAC length is fixed and too
+	 * large to leave sufficient option space.
+	 */
+	syn_tcp_option_space = MAX_TCP_OPTION_SPACE;
+	syn_tcp_option_space -= TCPOLEN_MSS_ALIGNED;
+	syn_tcp_option_space -= TCPOLEN_TSTAMP_ALIGNED;
+	syn_tcp_option_space -= TCPOLEN_WSCALE_ALIGNED;
+	if (tcp_ao_len_aligned(key) > syn_tcp_option_space) {
+		err = -EMSGSIZE;
+		goto err_kfree;
+	}
+
+	key->keylen = cmd->keylen;
+	memcpy(key->key, cmd->key, cmd->keylen);
+
+	err = tcp_sigpool_start(key->tcp_sigpool_id, &hp);
+	if (err)
+		goto err_kfree;
+
+	tfm = crypto_ahash_reqtfm(hp.req);
+	if (is_kdf_aes_128_cmac) {
+		void *scratch = hp.scratch;
+		struct scatterlist sg;
+
+		memcpy(tmp_key, cmd->key, cmd->keylen);
+		sg_init_one(&sg, tmp_key, cmd->keylen);
+
+		/* Using zero-key of 16 bytes as described in RFC5926 */
+		memset(scratch, 0, 16);
+		err = crypto_ahash_setkey(tfm, scratch, 16);
+		if (err)
+			goto err_pool_end;
+
+		err = crypto_ahash_init(hp.req);
+		if (err)
+			goto err_pool_end;
+
+		ahash_request_set_crypt(hp.req, &sg, key->key, cmd->keylen);
+		err = crypto_ahash_update(hp.req);
+		if (err)
+			goto err_pool_end;
+
+		err |= crypto_ahash_final(hp.req);
+		if (err)
+			goto err_pool_end;
+		key->keylen = 16;
+	}
+
+	err = crypto_ahash_setkey(tfm, key->key, key->keylen);
+	if (err)
+		goto err_pool_end;
+
+	tcp_sigpool_end(&hp);
+	kfree_sensitive(tmp_key);
+
+	if (tcp_ao_maclen(key) > key->digest_size)
+		return -EINVAL;
+
+	return 0;
+
+err_pool_end:
+	tcp_sigpool_end(&hp);
+err_kfree:
+	kfree_sensitive(tmp_key);
+	return err;
+}
+
+#if IS_ENABLED(CONFIG_IPV6)
+static int tcp_ao_verify_ipv6(struct sock *sk, struct tcp_ao_add *cmd,
+			      union tcp_ao_addr **paddr,
+			      unsigned short int *family)
+{
+	struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)&cmd->addr;
+	struct in6_addr *addr = &sin6->sin6_addr;
+	u8 prefix = cmd->prefix;
+
+	if (sin6->sin6_family != AF_INET6)
+		return -EINVAL;
+
+	/* Currently matching is not performed on port (or port ranges) */
+	if (sin6->sin6_port != 0)
+		return -EINVAL;
+
+	/* Check prefix and trailing 0's in addr */
+	if (cmd->prefix != 0 && ipv6_addr_v4mapped(addr)) {
+		__be32 addr4 = addr->s6_addr32[3];
+		__be32 mask;
+
+		if (prefix > 32 || ntohl(addr4) == INADDR_ANY)
+			return -EINVAL;
+
+		mask = inet_make_mask(prefix);
+		if (addr4 & ~mask)
+			return -EINVAL;
+
+		/* Check that MKT address is consistent with socket */
+		if (!ipv6_addr_any(&sk->sk_v6_daddr)) {
+			__be32 daddr4 = sk->sk_v6_daddr.s6_addr32[3];
+
+			if (!ipv6_addr_v4mapped(&sk->sk_v6_daddr))
+				return -EINVAL;
+			if ((daddr4 & mask) != addr4)
+				return -EINVAL;
+		}
+
+		*paddr = (union tcp_ao_addr *)&addr->s6_addr32[3];
+		*family = AF_INET;
+		return 0;
+	} else if (cmd->prefix != 0) {
+		struct in6_addr pfx;
+
+		if (ipv6_addr_any(addr) || prefix > 128)
+			return -EINVAL;
+
+		ipv6_addr_prefix(&pfx, addr, prefix);
+		if (ipv6_addr_cmp(&pfx, addr))
+			return -EINVAL;
+
+		/* Check that MKT address is consistent with socket */
+		if (!ipv6_addr_any(&sk->sk_v6_daddr) &&
+		    !ipv6_prefix_equal(&sk->sk_v6_daddr, addr, prefix))
+
+			return -EINVAL;
+	} else {
+		if (!ipv6_addr_any(addr))
+			return -EINVAL;
+	}
+
+	*paddr = (union tcp_ao_addr *)addr;
+	return 0;
+}
+#else
+static int tcp_ao_verify_ipv6(struct sock *sk, struct tcp_ao_add *cmd,
+			      union tcp_ao_addr **paddr,
+			      unsigned short int *family)
+{
+	return -EOPNOTSUPP;
+}
+#endif
+
+static struct tcp_ao_info *setsockopt_ao_info(struct sock *sk)
+{
+	if (sk_fullsock(sk)) {
+		return rcu_dereference_protected(tcp_sk(sk)->ao_info,
+						 lockdep_sock_is_held(sk));
+	} else if (sk->sk_state == TCP_TIME_WAIT) {
+		return rcu_dereference_protected(tcp_twsk(sk)->ao_info,
+						 lockdep_sock_is_held(sk));
+	}
+	return ERR_PTR(-ESOCKTNOSUPPORT);
+}
+
+static struct tcp_ao_info *getsockopt_ao_info(struct sock *sk)
+{
+	if (sk_fullsock(sk))
+		return rcu_dereference(tcp_sk(sk)->ao_info);
+	else if (sk->sk_state == TCP_TIME_WAIT)
+		return rcu_dereference(tcp_twsk(sk)->ao_info);
+
+	return ERR_PTR(-ESOCKTNOSUPPORT);
+}
+
+#define TCP_AO_KEYF_ALL (TCP_AO_KEYF_IFINDEX | TCP_AO_KEYF_EXCLUDE_OPT)
+#define TCP_AO_GET_KEYF_VALID	(TCP_AO_KEYF_IFINDEX)
+
+static struct tcp_ao_key *tcp_ao_key_alloc(struct sock *sk,
+					   struct tcp_ao_add *cmd)
+{
+	const char *algo = cmd->alg_name;
+	unsigned int digest_size;
+	struct crypto_ahash *tfm;
+	struct tcp_ao_key *key;
+	struct tcp_sigpool hp;
+	int err, pool_id;
+	size_t size;
+
+	/* Force null-termination of alg_name */
+	cmd->alg_name[ARRAY_SIZE(cmd->alg_name) - 1] = '\0';
+
+	/* RFC5926, 3.1.1.2. KDF_AES_128_CMAC */
+	if (!strcmp("cmac(aes128)", algo))
+		algo = "cmac(aes)";
+
+	/* Full TCP header (th->doff << 2) should fit into scratch area,
+	 * see tcp_ao_hash_header().
+	 */
+	pool_id = tcp_sigpool_alloc_ahash(algo, 60);
+	if (pool_id < 0)
+		return ERR_PTR(pool_id);
+
+	err = tcp_sigpool_start(pool_id, &hp);
+	if (err)
+		goto err_free_pool;
+
+	tfm = crypto_ahash_reqtfm(hp.req);
+	digest_size = crypto_ahash_digestsize(tfm);
+	tcp_sigpool_end(&hp);
+
+	size = sizeof(struct tcp_ao_key) + (digest_size << 1);
+	key = sock_kmalloc(sk, size, GFP_KERNEL);
+	if (!key) {
+		err = -ENOMEM;
+		goto err_free_pool;
+	}
+
+	key->tcp_sigpool_id = pool_id;
+	key->digest_size = digest_size;
+	return key;
+
+err_free_pool:
+	tcp_sigpool_release(pool_id);
+	return ERR_PTR(err);
+}
+
+static int tcp_ao_add_cmd(struct sock *sk, unsigned short int family,
+			  sockptr_t optval, int optlen)
+{
+	struct tcp_ao_info *ao_info;
+	union tcp_ao_addr *addr;
+	struct tcp_ao_key *key;
+	struct tcp_ao_add cmd;
+	int ret, l3index = 0;
+	bool first = false;
+
+	if (optlen < sizeof(cmd))
+		return -EINVAL;
+
+	ret = copy_struct_from_sockptr(&cmd, sizeof(cmd), optval, optlen);
+	if (ret)
+		return ret;
+
+	if (cmd.keylen > TCP_AO_MAXKEYLEN)
+		return -EINVAL;
+
+	if (cmd.reserved != 0 || cmd.reserved2 != 0)
+		return -EINVAL;
+
+	if (family == AF_INET)
+		ret = tcp_ao_verify_ipv4(sk, &cmd, &addr);
+	else
+		ret = tcp_ao_verify_ipv6(sk, &cmd, &addr, &family);
+	if (ret)
+		return ret;
+
+	if (cmd.keyflags & ~TCP_AO_KEYF_ALL)
+		return -EINVAL;
+
+	if (cmd.set_current || cmd.set_rnext) {
+		if (!tcp_ao_can_set_current_rnext(sk))
+			return -EINVAL;
+	}
+
+	if (cmd.ifindex && !(cmd.keyflags & TCP_AO_KEYF_IFINDEX))
+		return -EINVAL;
+
+	/* For cmd.tcp_ifindex = 0 the key will apply to the default VRF */
+	if (cmd.keyflags & TCP_AO_KEYF_IFINDEX && cmd.ifindex) {
+		int bound_dev_if = READ_ONCE(sk->sk_bound_dev_if);
+		struct net_device *dev;
+
+		rcu_read_lock();
+		dev = dev_get_by_index_rcu(sock_net(sk), cmd.ifindex);
+		if (dev && netif_is_l3_master(dev))
+			l3index = dev->ifindex;
+		rcu_read_unlock();
+
+		if (!dev || !l3index)
+			return -EINVAL;
+
+		if (!bound_dev_if || bound_dev_if != cmd.ifindex) {
+			/* tcp_ao_established_key() doesn't expect having
+			 * non peer-matching key on an established TCP-AO
+			 * connection.
+			 */
+			if (!((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE)))
+				return -EINVAL;
+		}
+
+		/* It's still possible to bind after adding keys or even
+		 * re-bind to a different dev (with CAP_NET_RAW).
+		 * So, no reason to return error here, rather try to be
+		 * nice and warn the user.
+		 */
+		if (bound_dev_if && bound_dev_if != cmd.ifindex)
+			net_warn_ratelimited("AO key ifindex %d != sk bound ifindex %d\n",
+					     cmd.ifindex, bound_dev_if);
+	}
+
+	/* Don't allow keys for peers that have a matching TCP-MD5 key */
+	if (cmd.keyflags & TCP_AO_KEYF_IFINDEX) {
+		/* Non-_exact version of tcp_md5_do_lookup() will
+		 * as well match keys that aren't bound to a specific VRF
+		 * (that will make them match AO key with
+		 * sysctl_tcp_l3dev_accept = 1
+		 */
+		if (tcp_md5_do_lookup(sk, l3index, addr, family))
+			return -EKEYREJECTED;
+	} else {
+		if (tcp_md5_do_lookup_any_l3index(sk, addr, family))
+			return -EKEYREJECTED;
+	}
+
+	ao_info = setsockopt_ao_info(sk);
+	if (IS_ERR(ao_info))
+		return PTR_ERR(ao_info);
+
+	if (!ao_info) {
+		ao_info = tcp_ao_alloc_info(GFP_KERNEL);
+		if (!ao_info)
+			return -ENOMEM;
+		first = true;
+	} else {
+		/* Check that neither RecvID nor SendID match any
+		 * existing key for the peer, RFC5925 3.1:
+		 * > The IDs of MKTs MUST NOT overlap where their
+		 * > TCP connection identifiers overlap.
+		 */
+		if (__tcp_ao_do_lookup(sk, l3index, addr, family, cmd.prefix, -1, cmd.rcvid))
+			return -EEXIST;
+		if (__tcp_ao_do_lookup(sk, l3index, addr, family,
+				       cmd.prefix, cmd.sndid, -1))
+			return -EEXIST;
+	}
+
+	key = tcp_ao_key_alloc(sk, &cmd);
+	if (IS_ERR(key)) {
+		ret = PTR_ERR(key);
+		goto err_free_ao;
+	}
+
+	INIT_HLIST_NODE(&key->node);
+	memcpy(&key->addr, addr, (family == AF_INET) ? sizeof(struct in_addr) :
+						       sizeof(struct in6_addr));
+	key->prefixlen	= cmd.prefix;
+	key->family	= family;
+	key->keyflags	= cmd.keyflags;
+	key->sndid	= cmd.sndid;
+	key->rcvid	= cmd.rcvid;
+	key->l3index	= l3index;
+	atomic64_set(&key->pkt_good, 0);
+	atomic64_set(&key->pkt_bad, 0);
+
+	ret = tcp_ao_parse_crypto(&cmd, key);
+	if (ret < 0)
+		goto err_free_sock;
+
+	if (!((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE))) {
+		tcp_ao_cache_traffic_keys(sk, ao_info, key);
+		if (first) {
+			ao_info->current_key = key;
+			ao_info->rnext_key = key;
+		}
+	}
+
+	tcp_ao_link_mkt(ao_info, key);
+	if (first) {
+		if (!static_branch_inc(&tcp_ao_needed.key)) {
+			ret = -EUSERS;
+			goto err_free_sock;
+		}
+		sk_gso_disable(sk);
+		rcu_assign_pointer(tcp_sk(sk)->ao_info, ao_info);
+	}
+
+	if (cmd.set_current)
+		WRITE_ONCE(ao_info->current_key, key);
+	if (cmd.set_rnext)
+		WRITE_ONCE(ao_info->rnext_key, key);
+	return 0;
+
+err_free_sock:
+	atomic_sub(tcp_ao_sizeof_key(key), &sk->sk_omem_alloc);
+	tcp_sigpool_release(key->tcp_sigpool_id);
+	kfree_sensitive(key);
+err_free_ao:
+	if (first)
+		kfree(ao_info);
+	return ret;
+}
+
+static int tcp_ao_delete_key(struct sock *sk, struct tcp_ao_info *ao_info,
+			     bool del_async, struct tcp_ao_key *key,
+			     struct tcp_ao_key *new_current,
+			     struct tcp_ao_key *new_rnext)
+{
+	int err;
+
+	hlist_del_rcu(&key->node);
+
+	/* Support for async delete on listening sockets: as they don't
+	 * need current_key/rnext_key maintaining, we don't need to check
+	 * them and we can just free all resources in RCU fashion.
+	 */
+	if (del_async) {
+		atomic_sub(tcp_ao_sizeof_key(key), &sk->sk_omem_alloc);
+		call_rcu(&key->rcu, tcp_ao_key_free_rcu);
+		return 0;
+	}
+
+	/* At this moment another CPU could have looked this key up
+	 * while it was unlinked from the list. Wait for RCU grace period,
+	 * after which the key is off-list and can't be looked up again;
+	 * the rx path [just before RCU came] might have used it and set it
+	 * as current_key (very unlikely).
+	 * Free the key with next RCU grace period (in case it was
+	 * current_key before tcp_ao_current_rnext() might have
+	 * changed it in forced-delete).
+	 */
+	synchronize_rcu();
+	if (new_current)
+		WRITE_ONCE(ao_info->current_key, new_current);
+	if (new_rnext)
+		WRITE_ONCE(ao_info->rnext_key, new_rnext);
+
+	if (unlikely(READ_ONCE(ao_info->current_key) == key ||
+		     READ_ONCE(ao_info->rnext_key) == key)) {
+		err = -EBUSY;
+		goto add_key;
+	}
+
+	atomic_sub(tcp_ao_sizeof_key(key), &sk->sk_omem_alloc);
+	call_rcu(&key->rcu, tcp_ao_key_free_rcu);
+
+	return 0;
+add_key:
+	hlist_add_head_rcu(&key->node, &ao_info->head);
+	return err;
+}
+
+#define TCP_AO_DEL_KEYF_ALL (TCP_AO_KEYF_IFINDEX)
+static int tcp_ao_del_cmd(struct sock *sk, unsigned short int family,
+			  sockptr_t optval, int optlen)
+{
+	struct tcp_ao_key *key, *new_current = NULL, *new_rnext = NULL;
+	int err, addr_len, l3index = 0;
+	struct tcp_ao_info *ao_info;
+	union tcp_ao_addr *addr;
+	struct tcp_ao_del cmd;
+	__u8 prefix;
+	u16 port;
+
+	if (optlen < sizeof(cmd))
+		return -EINVAL;
+
+	err = copy_struct_from_sockptr(&cmd, sizeof(cmd), optval, optlen);
+	if (err)
+		return err;
+
+	if (cmd.reserved != 0 || cmd.reserved2 != 0)
+		return -EINVAL;
+
+	if (cmd.set_current || cmd.set_rnext) {
+		if (!tcp_ao_can_set_current_rnext(sk))
+			return -EINVAL;
+	}
+
+	if (cmd.keyflags & ~TCP_AO_DEL_KEYF_ALL)
+		return -EINVAL;
+
+	/* No sanity check for TCP_AO_KEYF_IFINDEX as if a VRF
+	 * was destroyed, there still should be a way to delete keys,
+	 * that were bound to that l3intf. So, fail late at lookup stage
+	 * if there is no key for that ifindex.
+	 */
+	if (cmd.ifindex && !(cmd.keyflags & TCP_AO_KEYF_IFINDEX))
+		return -EINVAL;
+
+	ao_info = setsockopt_ao_info(sk);
+	if (IS_ERR(ao_info))
+		return PTR_ERR(ao_info);
+	if (!ao_info)
+		return -ENOENT;
+
+	/* For sockets in TCP_CLOSED it's possible set keys that aren't
+	 * matching the future peer (address/VRF/etc),
+	 * tcp_ao_connect_init() will choose a correct matching MKT
+	 * if there's any.
+	 */
+	if (cmd.set_current) {
+		new_current = tcp_ao_established_key(ao_info, cmd.current_key, -1);
+		if (!new_current)
+			return -ENOENT;
+	}
+	if (cmd.set_rnext) {
+		new_rnext = tcp_ao_established_key(ao_info, -1, cmd.rnext);
+		if (!new_rnext)
+			return -ENOENT;
+	}
+	if (cmd.del_async && sk->sk_state != TCP_LISTEN)
+		return -EINVAL;
+
+	if (family == AF_INET) {
+		struct sockaddr_in *sin = (struct sockaddr_in *)&cmd.addr;
+
+		addr = (union tcp_ao_addr *)&sin->sin_addr;
+		addr_len = sizeof(struct in_addr);
+		port = ntohs(sin->sin_port);
+	} else {
+		struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)&cmd.addr;
+		struct in6_addr *addr6 = &sin6->sin6_addr;
+
+		if (ipv6_addr_v4mapped(addr6)) {
+			addr = (union tcp_ao_addr *)&addr6->s6_addr32[3];
+			addr_len = sizeof(struct in_addr);
+			family = AF_INET;
+		} else {
+			addr = (union tcp_ao_addr *)addr6;
+			addr_len = sizeof(struct in6_addr);
+		}
+		port = ntohs(sin6->sin6_port);
+	}
+	prefix = cmd.prefix;
+
+	/* Currently matching is not performed on port (or port ranges) */
+	if (port != 0)
+		return -EINVAL;
+
+	/* We could choose random present key here for current/rnext
+	 * but that's less predictable. Let's be strict and don't
+	 * allow removing a key that's in use. RFC5925 doesn't
+	 * specify how-to coordinate key removal, but says:
+	 * "It is presumed that an MKT affecting a particular
+	 * connection cannot be destroyed during an active connection"
+	 */
+	hlist_for_each_entry_rcu(key, &ao_info->head, node) {
+		if (cmd.sndid != key->sndid ||
+		    cmd.rcvid != key->rcvid)
+			continue;
+
+		if (family != key->family ||
+		    prefix != key->prefixlen ||
+		    memcmp(addr, &key->addr, addr_len))
+			continue;
+
+		if ((cmd.keyflags & TCP_AO_KEYF_IFINDEX) !=
+		    (key->keyflags & TCP_AO_KEYF_IFINDEX))
+			continue;
+
+		if (key->l3index != l3index)
+			continue;
+
+		if (key == new_current || key == new_rnext)
+			continue;
+
+		return tcp_ao_delete_key(sk, ao_info, cmd.del_async, key,
+					 new_current, new_rnext);
+	}
+	return -ENOENT;
+}
+
+/* cmd.ao_required makes a socket TCP-AO only.
+ * Don't allow any md5 keys for any l3intf on the socket together with it.
+ * Restricting it early in setsockopt() removes a check for
+ * ao_info->ao_required on inbound tcp segment fast-path.
+ */
+static int tcp_ao_required_verify(struct sock *sk)
+{
+#ifdef CONFIG_TCP_MD5SIG
+	const struct tcp_md5sig_info *md5sig;
+
+	if (!static_branch_unlikely(&tcp_md5_needed.key))
+		return 0;
+
+	md5sig = rcu_dereference_check(tcp_sk(sk)->md5sig_info,
+				       lockdep_sock_is_held(sk));
+	if (!md5sig)
+		return 0;
+
+	if (rcu_dereference_check(hlist_first_rcu(&md5sig->head),
+				  lockdep_sock_is_held(sk)))
+		return 1;
+#endif
+	return 0;
+}
+
+static int tcp_ao_info_cmd(struct sock *sk, unsigned short int family,
+			   sockptr_t optval, int optlen)
+{
+	struct tcp_ao_key *new_current = NULL, *new_rnext = NULL;
+	struct tcp_ao_info *ao_info;
+	struct tcp_ao_info_opt cmd;
+	bool first = false;
+	int err;
+
+	if (optlen < sizeof(cmd))
+		return -EINVAL;
+
+	err = copy_struct_from_sockptr(&cmd, sizeof(cmd), optval, optlen);
+	if (err)
+		return err;
+
+	if (cmd.set_current || cmd.set_rnext) {
+		if (!tcp_ao_can_set_current_rnext(sk))
+			return -EINVAL;
+	}
+
+	if (cmd.reserved != 0 || cmd.reserved2 != 0)
+		return -EINVAL;
+
+	ao_info = setsockopt_ao_info(sk);
+	if (IS_ERR(ao_info))
+		return PTR_ERR(ao_info);
+	if (!ao_info) {
+		if (!((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE)))
+			return -EINVAL;
+		ao_info = tcp_ao_alloc_info(GFP_KERNEL);
+		if (!ao_info)
+			return -ENOMEM;
+		first = true;
+	}
+
+	if (cmd.ao_required && tcp_ao_required_verify(sk))
+		return -EKEYREJECTED;
+
+	/* For sockets in TCP_CLOSED it's possible set keys that aren't
+	 * matching the future peer (address/port/VRF/etc),
+	 * tcp_ao_connect_init() will choose a correct matching MKT
+	 * if there's any.
+	 */
+	if (cmd.set_current) {
+		new_current = tcp_ao_established_key(ao_info, cmd.current_key, -1);
+		if (!new_current) {
+			err = -ENOENT;
+			goto out;
+		}
+	}
+	if (cmd.set_rnext) {
+		new_rnext = tcp_ao_established_key(ao_info, -1, cmd.rnext);
+		if (!new_rnext) {
+			err = -ENOENT;
+			goto out;
+		}
+	}
+	if (cmd.set_counters) {
+		atomic64_set(&ao_info->counters.pkt_good, cmd.pkt_good);
+		atomic64_set(&ao_info->counters.pkt_bad, cmd.pkt_bad);
+		atomic64_set(&ao_info->counters.key_not_found, cmd.pkt_key_not_found);
+		atomic64_set(&ao_info->counters.ao_required, cmd.pkt_ao_required);
+		atomic64_set(&ao_info->counters.dropped_icmp, cmd.pkt_dropped_icmp);
+	}
+
+	ao_info->ao_required = cmd.ao_required;
+	ao_info->accept_icmps = cmd.accept_icmps;
+	if (new_current)
+		WRITE_ONCE(ao_info->current_key, new_current);
+	if (new_rnext)
+		WRITE_ONCE(ao_info->rnext_key, new_rnext);
+	if (first) {
+		if (!static_branch_inc(&tcp_ao_needed.key)) {
+			err = -EUSERS;
+			goto out;
+		}
+		sk_gso_disable(sk);
+		rcu_assign_pointer(tcp_sk(sk)->ao_info, ao_info);
+	}
+	return 0;
+out:
+	if (first)
+		kfree(ao_info);
+	return err;
+}
+
+int tcp_parse_ao(struct sock *sk, int cmd, unsigned short int family,
+		 sockptr_t optval, int optlen)
+{
+	if (WARN_ON_ONCE(family != AF_INET && family != AF_INET6))
+		return -EAFNOSUPPORT;
+
+	switch (cmd) {
+	case TCP_AO_ADD_KEY:
+		return tcp_ao_add_cmd(sk, family, optval, optlen);
+	case TCP_AO_DEL_KEY:
+		return tcp_ao_del_cmd(sk, family, optval, optlen);
+	case TCP_AO_INFO:
+		return tcp_ao_info_cmd(sk, family, optval, optlen);
+	default:
+		WARN_ON_ONCE(1);
+		return -EINVAL;
+	}
+}
+
+int tcp_v4_parse_ao(struct sock *sk, int cmd, sockptr_t optval, int optlen)
+{
+	return tcp_parse_ao(sk, cmd, AF_INET, optval, optlen);
+}
+
+/* tcp_ao_copy_mkts_to_user(ao_info, optval, optlen)
+ *
+ * @ao_info:	struct tcp_ao_info on the socket that
+ *		socket getsockopt(TCP_AO_GET_KEYS) is executed on
+ * @optval:	pointer to array of tcp_ao_getsockopt structures in user space.
+ *		Must be != NULL.
+ * @optlen:	pointer to size of tcp_ao_getsockopt structure.
+ *		Must be != NULL.
+ *
+ * Return value: 0 on success, a negative error number otherwise.
+ *
+ * optval points to an array of tcp_ao_getsockopt structures in user space.
+ * optval[0] is used as both input and output to getsockopt. It determines
+ * which keys are returned by the kernel.
+ * optval[0].nkeys is the size of the array in user space. On return it contains
+ * the number of keys matching the search criteria.
+ * If tcp_ao_getsockopt::get_all is set, then all keys in the socket are
+ * returned, otherwise only keys matching <addr, prefix, sndid, rcvid>
+ * in optval[0] are returned.
+ * optlen is also used as both input and output. The user provides the size
+ * of struct tcp_ao_getsockopt in user space, and the kernel returns the size
+ * of the structure in kernel space.
+ * The size of struct tcp_ao_getsockopt may differ between user and kernel.
+ * There are three cases to consider:
+ *  * If usize == ksize, then keys are copied verbatim.
+ *  * If usize < ksize, then the userspace has passed an old struct to a
+ *    newer kernel. The rest of the trailing bytes in optval[0]
+ *    (ksize - usize) are interpreted as 0 by the kernel.
+ *  * If usize > ksize, then the userspace has passed a new struct to an
+ *    older kernel. The trailing bytes unknown to the kernel (usize - ksize)
+ *    are checked to ensure they are zeroed, otherwise -E2BIG is returned.
+ * On return the kernel fills in min(usize, ksize) in each entry of the array.
+ * The layout of the fields in the user and kernel structures is expected to
+ * be the same (including in the 32bit vs 64bit case).
+ */
+static int tcp_ao_copy_mkts_to_user(struct tcp_ao_info *ao_info,
+				    sockptr_t optval, sockptr_t optlen)
+{
+	struct tcp_ao_getsockopt opt_in, opt_out;
+	struct tcp_ao_key *key, *current_key;
+	bool do_address_matching = true;
+	union tcp_ao_addr *addr = NULL;
+	int err, l3index, user_len;
+	unsigned int max_keys;	/* maximum number of keys to copy to user */
+	size_t out_offset = 0;
+	size_t bytes_to_write;	/* number of bytes to write to user level */
+	u32 matched_keys;	/* keys from ao_info matched so far */
+	int optlen_out;
+	__be16 port = 0;
+
+	if (copy_from_sockptr(&user_len, optlen, sizeof(int)))
+		return -EFAULT;
+
+	if (user_len <= 0)
+		return -EINVAL;
+
+	memset(&opt_in, 0, sizeof(struct tcp_ao_getsockopt));
+	err = copy_struct_from_sockptr(&opt_in, sizeof(opt_in),
+				       optval, user_len);
+	if (err < 0)
+		return err;
+
+	if (opt_in.pkt_good || opt_in.pkt_bad)
+		return -EINVAL;
+	if (opt_in.keyflags & ~TCP_AO_GET_KEYF_VALID)
+		return -EINVAL;
+	if (opt_in.ifindex && !(opt_in.keyflags & TCP_AO_KEYF_IFINDEX))
+		return -EINVAL;
+
+	if (opt_in.reserved != 0)
+		return -EINVAL;
+
+	max_keys = opt_in.nkeys;
+	l3index = (opt_in.keyflags & TCP_AO_KEYF_IFINDEX) ? opt_in.ifindex : -1;
+
+	if (opt_in.get_all || opt_in.is_current || opt_in.is_rnext) {
+		if (opt_in.get_all && (opt_in.is_current || opt_in.is_rnext))
+			return -EINVAL;
+		do_address_matching = false;
+	}
+
+	switch (opt_in.addr.ss_family) {
+	case AF_INET: {
+		struct sockaddr_in *sin;
+		__be32 mask;
+
+		sin = (struct sockaddr_in *)&opt_in.addr;
+		port = sin->sin_port;
+		addr = (union tcp_ao_addr *)&sin->sin_addr;
+
+		if (opt_in.prefix > 32)
+			return -EINVAL;
+
+		if (ntohl(sin->sin_addr.s_addr) == INADDR_ANY &&
+		    opt_in.prefix != 0)
+			return -EINVAL;
+
+		mask = inet_make_mask(opt_in.prefix);
+		if (sin->sin_addr.s_addr & ~mask)
+			return -EINVAL;
+
+		break;
+	}
+	case AF_INET6: {
+		struct sockaddr_in6 *sin6;
+		struct in6_addr *addr6;
+
+		sin6 = (struct sockaddr_in6 *)&opt_in.addr;
+		addr = (union tcp_ao_addr *)&sin6->sin6_addr;
+		addr6 = &sin6->sin6_addr;
+		port = sin6->sin6_port;
+
+		/* We don't have to change family and @addr here if
+		 * ipv6_addr_v4mapped() like in key adding:
+		 * tcp_ao_key_cmp() does it. Do the sanity checks though.
+		 */
+		if (opt_in.prefix != 0) {
+			if (ipv6_addr_v4mapped(addr6)) {
+				__be32 mask, addr4 = addr6->s6_addr32[3];
+
+				if (opt_in.prefix > 32 ||
+				    ntohl(addr4) == INADDR_ANY)
+					return -EINVAL;
+				mask = inet_make_mask(opt_in.prefix);
+				if (addr4 & ~mask)
+					return -EINVAL;
+			} else {
+				struct in6_addr pfx;
+
+				if (ipv6_addr_any(addr6) ||
+				    opt_in.prefix > 128)
+					return -EINVAL;
+
+				ipv6_addr_prefix(&pfx, addr6, opt_in.prefix);
+				if (ipv6_addr_cmp(&pfx, addr6))
+					return -EINVAL;
+			}
+		} else if (!ipv6_addr_any(addr6)) {
+			return -EINVAL;
+		}
+		break;
+	}
+	case 0:
+		if (!do_address_matching)
+			break;
+		fallthrough;
+	default:
+		return -EAFNOSUPPORT;
+	}
+
+	if (!do_address_matching) {
+		/* We could just ignore those, but let's do stricter checks */
+		if (addr || port)
+			return -EINVAL;
+		if (opt_in.prefix || opt_in.sndid || opt_in.rcvid)
+			return -EINVAL;
+	}
+
+	bytes_to_write = min_t(int, user_len, sizeof(struct tcp_ao_getsockopt));
+	matched_keys = 0;
+	/* May change in RX, while we're dumping, pre-fetch it */
+	current_key = READ_ONCE(ao_info->current_key);
+
+	hlist_for_each_entry_rcu(key, &ao_info->head, node) {
+		if (opt_in.get_all)
+			goto match;
+
+		if (opt_in.is_current || opt_in.is_rnext) {
+			if (opt_in.is_current && key == current_key)
+				goto match;
+			if (opt_in.is_rnext && key == ao_info->rnext_key)
+				goto match;
+			continue;
+		}
+
+		if (tcp_ao_key_cmp(key, l3index, addr, opt_in.prefix,
+				   opt_in.addr.ss_family,
+				   opt_in.sndid, opt_in.rcvid) != 0)
+			continue;
+match:
+		matched_keys++;
+		if (matched_keys > max_keys)
+			continue;
+
+		memset(&opt_out, 0, sizeof(struct tcp_ao_getsockopt));
+
+		if (key->family == AF_INET) {
+			struct sockaddr_in *sin_out = (struct sockaddr_in *)&opt_out.addr;
+
+			sin_out->sin_family = key->family;
+			sin_out->sin_port = 0;
+			memcpy(&sin_out->sin_addr, &key->addr, sizeof(struct in_addr));
+		} else {
+			struct sockaddr_in6 *sin6_out = (struct sockaddr_in6 *)&opt_out.addr;
+
+			sin6_out->sin6_family = key->family;
+			sin6_out->sin6_port = 0;
+			memcpy(&sin6_out->sin6_addr, &key->addr, sizeof(struct in6_addr));
+		}
+		opt_out.sndid = key->sndid;
+		opt_out.rcvid = key->rcvid;
+		opt_out.prefix = key->prefixlen;
+		opt_out.keyflags = key->keyflags;
+		opt_out.is_current = (key == current_key);
+		opt_out.is_rnext = (key == ao_info->rnext_key);
+		opt_out.nkeys = 0;
+		opt_out.maclen = key->maclen;
+		opt_out.keylen = key->keylen;
+		opt_out.ifindex = key->l3index;
+		opt_out.pkt_good = atomic64_read(&key->pkt_good);
+		opt_out.pkt_bad = atomic64_read(&key->pkt_bad);
+		memcpy(&opt_out.key, key->key, key->keylen);
+		tcp_sigpool_algo(key->tcp_sigpool_id, opt_out.alg_name, 64);
+
+		/* Copy key to user */
+		if (copy_to_sockptr_offset(optval, out_offset,
+					   &opt_out, bytes_to_write))
+			return -EFAULT;
+		out_offset += user_len;
+	}
+
+	optlen_out = (int)sizeof(struct tcp_ao_getsockopt);
+	if (copy_to_sockptr(optlen, &optlen_out, sizeof(int)))
+		return -EFAULT;
+
+	out_offset = offsetof(struct tcp_ao_getsockopt, nkeys);
+	if (copy_to_sockptr_offset(optval, out_offset,
+				   &matched_keys, sizeof(u32)))
+		return -EFAULT;
+
+	return 0;
+}
+
+int tcp_ao_get_mkts(struct sock *sk, sockptr_t optval, sockptr_t optlen)
+{
+	struct tcp_ao_info *ao_info;
+
+	ao_info = setsockopt_ao_info(sk);
+	if (IS_ERR(ao_info))
+		return PTR_ERR(ao_info);
+	if (!ao_info)
+		return -ENOENT;
+
+	return tcp_ao_copy_mkts_to_user(ao_info, optval, optlen);
+}
+
+int tcp_ao_get_sock_info(struct sock *sk, sockptr_t optval, sockptr_t optlen)
+{
+	struct tcp_ao_info_opt out, in = {};
+	struct tcp_ao_key *current_key;
+	struct tcp_ao_info *ao;
+	int err, len;
+
+	if (copy_from_sockptr(&len, optlen, sizeof(int)))
+		return -EFAULT;
+
+	if (len <= 0)
+		return -EINVAL;
+
+	/* Copying this "in" only to check ::reserved, ::reserved2,
+	 * that may be needed to extend (struct tcp_ao_info_opt) and
+	 * what getsockopt() provides in future.
+	 */
+	err = copy_struct_from_sockptr(&in, sizeof(in), optval, len);
+	if (err)
+		return err;
+
+	if (in.reserved != 0 || in.reserved2 != 0)
+		return -EINVAL;
+
+	ao = setsockopt_ao_info(sk);
+	if (IS_ERR(ao))
+		return PTR_ERR(ao);
+	if (!ao)
+		return -ENOENT;
+
+	memset(&out, 0, sizeof(out));
+	out.ao_required		= ao->ao_required;
+	out.accept_icmps	= ao->accept_icmps;
+	out.pkt_good		= atomic64_read(&ao->counters.pkt_good);
+	out.pkt_bad		= atomic64_read(&ao->counters.pkt_bad);
+	out.pkt_key_not_found	= atomic64_read(&ao->counters.key_not_found);
+	out.pkt_ao_required	= atomic64_read(&ao->counters.ao_required);
+	out.pkt_dropped_icmp	= atomic64_read(&ao->counters.dropped_icmp);
+
+	current_key = READ_ONCE(ao->current_key);
+	if (current_key) {
+		out.set_current = 1;
+		out.current_key = current_key->sndid;
+	}
+	if (ao->rnext_key) {
+		out.set_rnext = 1;
+		out.rnext = ao->rnext_key->rcvid;
+	}
+
+	if (copy_to_sockptr(optval, &out, min_t(int, len, sizeof(out))))
+		return -EFAULT;
+
+	return 0;
+}
+
+int tcp_ao_set_repair(struct sock *sk, sockptr_t optval, unsigned int optlen)
+{
+	struct tcp_sock *tp = tcp_sk(sk);
+	struct tcp_ao_repair cmd;
+	struct tcp_ao_key *key;
+	struct tcp_ao_info *ao;
+	int err;
+
+	if (optlen < sizeof(cmd))
+		return -EINVAL;
+
+	err = copy_struct_from_sockptr(&cmd, sizeof(cmd), optval, optlen);
+	if (err)
+		return err;
+
+	if (!tp->repair)
+		return -EPERM;
+
+	ao = setsockopt_ao_info(sk);
+	if (IS_ERR(ao))
+		return PTR_ERR(ao);
+	if (!ao)
+		return -ENOENT;
+
+	WRITE_ONCE(ao->lisn, cmd.snt_isn);
+	WRITE_ONCE(ao->risn, cmd.rcv_isn);
+	WRITE_ONCE(ao->snd_sne, cmd.snd_sne);
+	WRITE_ONCE(ao->rcv_sne, cmd.rcv_sne);
+
+	hlist_for_each_entry_rcu(key, &ao->head, node)
+		tcp_ao_cache_traffic_keys(sk, ao, key);
+
+	return 0;
+}
+
+int tcp_ao_get_repair(struct sock *sk, sockptr_t optval, sockptr_t optlen)
+{
+	struct tcp_sock *tp = tcp_sk(sk);
+	struct tcp_ao_repair opt;
+	struct tcp_ao_info *ao;
+	int len;
+
+	if (copy_from_sockptr(&len, optlen, sizeof(int)))
+		return -EFAULT;
+
+	if (len <= 0)
+		return -EINVAL;
+
+	if (!tp->repair)
+		return -EPERM;
+
+	rcu_read_lock();
+	ao = getsockopt_ao_info(sk);
+	if (IS_ERR_OR_NULL(ao)) {
+		rcu_read_unlock();
+		return ao ? PTR_ERR(ao) : -ENOENT;
+	}
+
+	opt.snt_isn	= ao->lisn;
+	opt.rcv_isn	= ao->risn;
+	opt.snd_sne	= READ_ONCE(ao->snd_sne);
+	opt.rcv_sne	= READ_ONCE(ao->rcv_sne);
+	rcu_read_unlock();
+
+	if (copy_to_sockptr(optval, &opt, min_t(int, len, sizeof(opt))))
+		return -EFAULT;
+	return 0;
+}