1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * INET		An implementation of the TCP Authentication Option (TCP-AO).
4 *		See RFC5925.
5 *
6 * Authors:	Dmitry Safonov <dima@arista.com>
7 *		Francesco Ruggeri <fruggeri@arista.com>
8 *		Salam Noureddine <noureddine@arista.com>
9 */
10#include <crypto/hash.h>
11#include <linux/tcp.h>
12
13#include <net/tcp.h>
14#include <net/ipv6.h>
15
16static int tcp_v6_ao_calc_key(struct tcp_ao_key *mkt, u8 *key,
17			      const struct in6_addr *saddr,
18			      const struct in6_addr *daddr,
19			      __be16 sport, __be16 dport,
20			      __be32 sisn, __be32 disn)
21{
22	struct kdf_input_block {
23		u8			counter;
24		u8			label[6];
25		struct tcp6_ao_context	ctx;
26		__be16			outlen;
27	} __packed * tmp;
28	struct tcp_sigpool hp;
29	int err;
30
31	err = tcp_sigpool_start(mkt->tcp_sigpool_id, &hp);
32	if (err)
33		return err;
34
35	tmp = hp.scratch;
36	tmp->counter	= 1;
37	memcpy(tmp->label, "TCP-AO", 6);
38	tmp->ctx.saddr	= *saddr;
39	tmp->ctx.daddr	= *daddr;
40	tmp->ctx.sport	= sport;
41	tmp->ctx.dport	= dport;
42	tmp->ctx.sisn	= sisn;
43	tmp->ctx.disn	= disn;
44	tmp->outlen	= htons(tcp_ao_digest_size(mkt) * 8); /* in bits */
45
46	err = tcp_ao_calc_traffic_key(mkt, key, tmp, sizeof(*tmp), &hp);
47	tcp_sigpool_end(&hp);
48
49	return err;
50}
51
52int tcp_v6_ao_calc_key_skb(struct tcp_ao_key *mkt, u8 *key,
53			   const struct sk_buff *skb,
54			   __be32 sisn, __be32 disn)
55{
56	const struct ipv6hdr *iph = ipv6_hdr(skb);
57	const struct tcphdr *th = tcp_hdr(skb);
58
59	return tcp_v6_ao_calc_key(mkt, key, &iph->saddr,
60				  &iph->daddr, th->source,
61				  th->dest, sisn, disn);
62}
63
64int tcp_v6_ao_calc_key_sk(struct tcp_ao_key *mkt, u8 *key,
65			  const struct sock *sk, __be32 sisn,
66			  __be32 disn, bool send)
67{
68	if (send)
69		return tcp_v6_ao_calc_key(mkt, key, &sk->sk_v6_rcv_saddr,
70					  &sk->sk_v6_daddr, htons(sk->sk_num),
71					  sk->sk_dport, sisn, disn);
72	else
73		return tcp_v6_ao_calc_key(mkt, key, &sk->sk_v6_daddr,
74					  &sk->sk_v6_rcv_saddr, sk->sk_dport,
75					  htons(sk->sk_num), disn, sisn);
76}
77
78int tcp_v6_ao_calc_key_rsk(struct tcp_ao_key *mkt, u8 *key,
79			   struct request_sock *req)
80{
81	struct inet_request_sock *ireq = inet_rsk(req);
82
83	return tcp_v6_ao_calc_key(mkt, key,
84			&ireq->ir_v6_loc_addr, &ireq->ir_v6_rmt_addr,
85			htons(ireq->ir_num), ireq->ir_rmt_port,
86			htonl(tcp_rsk(req)->snt_isn),
87			htonl(tcp_rsk(req)->rcv_isn));
88}
89
90struct tcp_ao_key *tcp_v6_ao_lookup(const struct sock *sk,
91				    struct sock *addr_sk,
92				    int sndid, int rcvid)
93{
94	int l3index = l3mdev_master_ifindex_by_index(sock_net(sk),
95						     addr_sk->sk_bound_dev_if);
96	struct in6_addr *addr = &addr_sk->sk_v6_daddr;
97
98	return tcp_ao_do_lookup(sk, l3index, (union tcp_ao_addr *)addr,
99				AF_INET6, sndid, rcvid);
100}
101
102struct tcp_ao_key *tcp_v6_ao_lookup_rsk(const struct sock *sk,
103					struct request_sock *req,
104					int sndid, int rcvid)
105{
106	struct inet_request_sock *ireq = inet_rsk(req);
107	struct in6_addr *addr = &ireq->ir_v6_rmt_addr;
108	int l3index;
109
110	l3index = l3mdev_master_ifindex_by_index(sock_net(sk), ireq->ir_iif);
111	return tcp_ao_do_lookup(sk, l3index, (union tcp_ao_addr *)addr,
112				AF_INET6, sndid, rcvid);
113}
114
115int tcp_v6_ao_hash_pseudoheader(struct tcp_sigpool *hp,
116				const struct in6_addr *daddr,
117				const struct in6_addr *saddr, int nbytes)
118{
119	struct tcp6_pseudohdr *bp;
120	struct scatterlist sg;
121
122	bp = hp->scratch;
123	/* 1. TCP pseudo-header (RFC2460) */
124	bp->saddr = *saddr;
125	bp->daddr = *daddr;
126	bp->len = cpu_to_be32(nbytes);
127	bp->protocol = cpu_to_be32(IPPROTO_TCP);
128
129	sg_init_one(&sg, bp, sizeof(*bp));
130	ahash_request_set_crypt(hp->req, &sg, NULL, sizeof(*bp));
131	return crypto_ahash_update(hp->req);
132}
133
134int tcp_v6_ao_hash_skb(char *ao_hash, struct tcp_ao_key *key,
135		       const struct sock *sk, const struct sk_buff *skb,
136		       const u8 *tkey, int hash_offset, u32 sne)
137{
138	return tcp_ao_hash_skb(AF_INET6, ao_hash, key, sk, skb, tkey,
139			hash_offset, sne);
140}
141
142int tcp_v6_parse_ao(struct sock *sk, int cmd,
143		    sockptr_t optval, int optlen)
144{
145	return tcp_parse_ao(sk, cmd, AF_INET6, optval, optlen);
146}
147
148int tcp_v6_ao_synack_hash(char *ao_hash, struct tcp_ao_key *ao_key,
149			  struct request_sock *req, const struct sk_buff *skb,
150			  int hash_offset, u32 sne)
151{
152	void *hash_buf = NULL;
153	int err;
154
155	hash_buf = kmalloc(tcp_ao_digest_size(ao_key), GFP_ATOMIC);
156	if (!hash_buf)
157		return -ENOMEM;
158
159	err = tcp_v6_ao_calc_key_rsk(ao_key, hash_buf, req);
160	if (err)
161		goto out;
162
163	err = tcp_ao_hash_skb(AF_INET6, ao_hash, ao_key, req_to_sk(req), skb,
164			      hash_buf, hash_offset, sne);
165out:
166	kfree(hash_buf);
167	return err;
168}
169