// SPDX-License-Identifier: GPL-2.0-or-later /* * INET An implementation of the TCP Authentication Option (TCP-AO). * See RFC5925. * * Authors: Dmitry Safonov * Francesco Ruggeri * Salam Noureddine */ #define pr_fmt(fmt) "TCP: " fmt #include #include #include #include #include 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; } /* 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, 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 (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, 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, (union tcp_ao_addr *)&addr4, prefixlen, AF_INET, sndid, rcvid); } #endif return __tcp_ao_key_cmp(key, addr, prefixlen, family, sndid, rcvid); } static struct tcp_ao_key *__tcp_ao_do_lookup(const struct sock *sk, const union tcp_ao_addr *addr, int family, u8 prefix, int sndid, int rcvid) { struct tcp_ao_key *key; struct tcp_ao_info *ao; 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, addr, prefixlen, family, sndid, rcvid)) return key; } return NULL; } struct tcp_ao_key *tcp_ao_do_lookup(const struct sock *sk, const union tcp_ao_addr *addr, int family, int sndid, int rcvid) { return __tcp_ao_do_lookup(sk, 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); 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); } 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; } /* 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, false, 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, false, 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) { union tcp_ao_addr *addr = (union tcp_ao_addr *)&inet_rsk(req)->ir_rmt_addr; return tcp_ao_do_lookup(sk, 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) { union tcp_ao_addr *addr = (union tcp_ao_addr *)&addr_sk->sk_daddr; return tcp_ao_do_lookup(sk, 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, 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 = 0; } 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, 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; if (sk->sk_state == TCP_TIME_WAIT) ao_info = rcu_dereference(tcp_twsk(sk)->ao_info); else ao_info = rcu_dereference(tcp_sk(sk)->ao_info); 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 = 0; } 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; 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); } tp->af_specific->calc_ao_hash(hash_location, key, sk, skb, traffic_key, hash_location - (u8 *)th, 0); 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) { if (family == AF_INET) { const struct iphdr *iph = ip_hdr(skb); return tcp_ao_do_lookup(sk, (union tcp_ao_addr *)&iph->saddr, AF_INET, sndid, rcvid); } else { const struct ipv6hdr *iph = ipv6_hdr(skb); return tcp_ao_do_lookup(sk, (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) { const struct tcphdr *th = tcp_hdr(skb); const struct tcp_ao_hdr *aoh; struct tcp_ao_key *key; treq->maclen = 0; if (tcp_parse_auth_options(th, NULL, &aoh) || !aoh) return; key = tcp_ao_inbound_lookup(family, sk, skb, -1, aoh->keyid); if (!key) /* Key not found, continue without TCP-AO */ return; treq->ao_rcv_next = aoh->keyid; treq->ao_keyid = aoh->rnext_keyid; treq->maclen = tcp_ao_maclen(key); } 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) { 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)) 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)) { kfree(hash_buf); return SKB_DROP_REASON_TCP_AOFAILURE; } 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, 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) 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 = 0; /* 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); 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); 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 = 0; 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 = 0; } 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); kfree(traffic_key); return ret; key_not_found: 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; 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; hlist_for_each_entry_rcu(key, &ao_info->head, node) { if (!tcp_ao_key_cmp(key, 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(key); ao_info->lisn = htonl(tp->write_seq); } 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); 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; union tcp_ao_addr *addr; bool match = false; int ret = -ENOMEM; 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; 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; } hlist_for_each_entry_rcu(key, &ao->head, node) { if (tcp_ao_key_cmp(key, 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; } 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 - wscale - sackperm), * 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_TSTAMP_ALIGNED; syn_tcp_option_space -= TCPOLEN_WSCALE_ALIGNED; syn_tcp_option_space -= TCPOLEN_SACKPERM_ALIGNED; if (tcp_ao_len(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); } #define TCP_AO_KEYF_ALL (0) 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); if (crypto_ahash_alignmask(tfm) > TCP_AO_KEY_ALIGN) { err = -EOPNOTSUPP; goto err_pool_end; } 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_pool_end: tcp_sigpool_end(&hp); 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; bool first = false; int ret; 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; } /* Don't allow keys for peers that have a matching TCP-MD5 key */ 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, addr, family, cmd.prefix, -1, cmd.rcvid)) return -EEXIST; if (__tcp_ao_do_lookup(sk, 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; ret = tcp_ao_parse_crypto(&cmd, key); if (ret < 0) goto err_free_sock; /* Change this condition if we allow adding keys in states * like close_wait, syn_sent or fin_wait... */ if (sk->sk_state == TCP_ESTABLISHED) tcp_ao_cache_traffic_keys(sk, ao_info, key); tcp_ao_link_mkt(ao_info, key); if (first) { 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, struct tcp_ao_key *key, struct tcp_ao_key *new_current, struct tcp_ao_key *new_rnext) { int err; hlist_del_rcu(&key->node); /* 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). */ 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; } 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; struct tcp_ao_info *ao_info; union tcp_ao_addr *addr; struct tcp_ao_del cmd; int addr_len; __u8 prefix; u16 port; int err; 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; } 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 (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 (key == new_current || key == new_rnext) continue; return tcp_ao_delete_key(sk, ao_info, 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) return -EINVAL; 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; } 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; } } ao_info->ao_required = cmd.ao_required; if (new_current) WRITE_ONCE(ao_info->current_key, new_current); if (new_rnext) WRITE_ONCE(ao_info->rnext_key, new_rnext); if (first) { 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); }