net/ipv6/tcp_ao.c

// 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>
 */
#include <linux/tcp.h>

#include <net/tcp.h>
#include <net/ipv6.h>

static void tcp_v6_ao_calc_key(struct tcp_ao_key *mkt, u8 *key,
			       const struct in6_addr *saddr,
			       const struct in6_addr *daddr,
			       __be16 sport, __be16 dport,
			       __be32 sisn, __be32 disn)
{
	struct kdf_input_block {
		u8			counter;
		u8			label[6];
		struct tcp6_ao_context	ctx;
		__be16			outlen;
	} __packed input = {
		.counter = 1,
		.label = "TCP-AO",
		.ctx = {
			.saddr = *saddr,
			.daddr = *daddr,
			.sport = sport,
			.dport = dport,
			.sisn = sisn,
			.disn = disn,
		},
		.outlen = htons(tcp_ao_digest_size(mkt) * 8), /* in bits */
	};

	tcp_ao_calc_traffic_key(mkt, key, &input, sizeof(input));
}

void tcp_v6_ao_calc_key_skb(struct tcp_ao_key *mkt, u8 *key,
			    const struct sk_buff *skb, __be32 sisn, __be32 disn)
{
	const struct ipv6hdr *iph = ipv6_hdr(skb);
	const struct tcphdr *th = tcp_hdr(skb);

	tcp_v6_ao_calc_key(mkt, key, &iph->saddr, &iph->daddr, th->source,
			   th->dest, sisn, disn);
}

void tcp_v6_ao_calc_key_sk(struct tcp_ao_key *mkt, u8 *key,
			   const struct sock *sk, __be32 sisn,
			   __be32 disn, bool send)
{
	if (send)
		tcp_v6_ao_calc_key(mkt, key, &sk->sk_v6_rcv_saddr,
				   &sk->sk_v6_daddr, htons(sk->sk_num),
				   sk->sk_dport, sisn, disn);
	else
		tcp_v6_ao_calc_key(mkt, key, &sk->sk_v6_daddr,
				   &sk->sk_v6_rcv_saddr, sk->sk_dport,
				   htons(sk->sk_num), disn, sisn);
}

void tcp_v6_ao_calc_key_rsk(struct tcp_ao_key *mkt, u8 *key,
			    struct request_sock *req)
{
	struct inet_request_sock *ireq = inet_rsk(req);

	tcp_v6_ao_calc_key(mkt, key,
			   &ireq->ir_v6_loc_addr, &ireq->ir_v6_rmt_addr,
			   htons(ireq->ir_num), ireq->ir_rmt_port,
			   htonl(tcp_rsk(req)->snt_isn),
			   htonl(tcp_rsk(req)->rcv_isn));
}

struct tcp_ao_key *tcp_v6_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);
	struct in6_addr *addr = &addr_sk->sk_v6_daddr;

	return tcp_ao_do_lookup(sk, l3index, (union tcp_ao_addr *)addr,
				AF_INET6, sndid, rcvid);
}

struct tcp_ao_key *tcp_v6_ao_lookup_rsk(const struct sock *sk,
					struct request_sock *req,
					int sndid, int rcvid)
{
	struct inet_request_sock *ireq = inet_rsk(req);
	struct in6_addr *addr = &ireq->ir_v6_rmt_addr;
	int l3index;

	l3index = l3mdev_master_ifindex_by_index(sock_net(sk), ireq->ir_iif);
	return tcp_ao_do_lookup(sk, l3index, (union tcp_ao_addr *)addr,
				AF_INET6, sndid, rcvid);
}

void tcp_v6_ao_hash_pseudoheader(struct tcp_ao_mac_ctx *mac_ctx,
				 const struct in6_addr *daddr,
				 const struct in6_addr *saddr, int nbytes)
{
	/* 1. TCP pseudo-header (RFC2460) */
	struct tcp6_pseudohdr phdr = {
		.saddr = *saddr,
		.daddr = *daddr,
		.len = cpu_to_be32(nbytes),
		.protocol = cpu_to_be32(IPPROTO_TCP),
	};

	tcp_ao_mac_update(mac_ctx, &phdr, sizeof(phdr));
}

int tcp_v6_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_INET6, ao_hash, key, sk, skb, tkey,
			hash_offset, sne);
}

int tcp_v6_parse_ao(struct sock *sk, int cmd,
		    sockptr_t optval, int optlen)
{
	return tcp_parse_ao(sk, cmd, AF_INET6, optval, optlen);
}

int tcp_v6_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)
{
	u8 tkey_buf[TCP_AO_MAX_TRAFFIC_KEY_LEN];

	tcp_v6_ao_calc_key_rsk(ao_key, tkey_buf, req);

	return tcp_ao_hash_skb(AF_INET6, ao_hash, ao_key, req_to_sk(req), skb,
			       tkey_buf, hash_offset, sne);
}