[v5,05/21] net/tcp: Calculate TCP-AO traffic keys

Message ID	20230403213420.1576559-6-dima@arista.com (mailing list archive)
State	Changes Requested
Delegated to:	Netdev Maintainers
Headers	show Return-Path: <netdev-owner@vger.kernel.org> From: Dmitry Safonov <dima@arista.com> To: linux-kernel@vger.kernel.org, David Ahern <dsahern@kernel.org>, Eric Dumazet <edumazet@google.com>, Paolo Abeni <pabeni@redhat.com>, Jakub Kicinski <kuba@kernel.org>, "David S. Miller" <davem@davemloft.net> Cc: Dmitry Safonov <dima@arista.com>, Andy Lutomirski <luto@amacapital.net>, Ard Biesheuvel <ardb@kernel.org>, Bob Gilligan <gilligan@arista.com>, Dan Carpenter <error27@gmail.com>, David Laight <David.Laight@aculab.com>, Dmitry Safonov <0x7f454c46@gmail.com>, Eric Biggers <ebiggers@kernel.org>, "Eric W. Biederman" <ebiederm@xmission.com>, Francesco Ruggeri <fruggeri05@gmail.com>, Herbert Xu <herbert@gondor.apana.org.au>, Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>, Ivan Delalande <colona@arista.com>, Leonard Crestez <cdleonard@gmail.com>, Salam Noureddine <noureddine@arista.com>, netdev@vger.kernel.org, Francesco Ruggeri <fruggeri@arista.com> Subject: [PATCH v5 05/21] net/tcp: Calculate TCP-AO traffic keys Date: Mon, 3 Apr 2023 22:34:04 +0100 Message-Id: <20230403213420.1576559-6-dima@arista.com> In-Reply-To: <20230403213420.1576559-1-dima@arista.com> References: <20230403213420.1576559-1-dima@arista.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk
Series	net/tcp: Add TCP-AO support \| expand [v5,00/21] net/tcp: Add TCP-AO support [v5,01/21,draft] net/tcp: Prepare tcp_md5sig_pool for TCP-AO [v5,02/21] net/tcp: Add TCP-AO config and structures [v5,03/21] net/tcp: Introduce TCP_AO setsockopt()s [v5,04/21] net/tcp: Prevent TCP-MD5 with TCP-AO being set [v5,05/21] net/tcp: Calculate TCP-AO traffic keys [v5,06/21] net/tcp: Add TCP-AO sign to outgoing packets [v5,07/21] net/tcp: Add tcp_parse_auth_options() [v5,08/21] net/tcp: Add AO sign to RST packets [v5,09/21] net/tcp: Add TCP-AO sign to twsk [v5,10/21] net/tcp: Wire TCP-AO to request sockets [v5,11/21] net/tcp: Sign SYN-ACK segments with TCP-AO [v5,12/21] net/tcp: Verify inbound TCP-AO signed segments [v5,13/21] net/tcp: Add TCP-AO segments counters [v5,14/21] net/tcp: Add TCP-AO SNE support [v5,15/21] net/tcp: Add tcp_hash_fail() ratelimited logs [v5,16/21] net/tcp: Ignore specific ICMPs for TCP-AO connections [v5,17/21] net/tcp: Add option for TCP-AO to (not) hash header [v5,18/21] net/tcp: Add TCP-AO getsockopt()s [v5,19/21] net/tcp: Allow asynchronous delete for TCP-AO keys (MKTs) [v5,20/21] net/tcp-ao: Add static_key for TCP-AO [v5,21/21] net/tcp-ao: Wire up l3index to TCP-AO

Context	Check	Description
netdev/tree_selection	success	Guessing tree name failed - patch did not apply, async

diff --git a/include/net/tcp.h b/include/net/tcp.h index fe3c0366db56..6d5ca08ab0c5 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -2118,6 +2118,11 @@ struct tcp_sock_af_ops { struct tcp_ao_key *(*ao_lookup)(const struct sock *sk, struct sock *addr_sk, int sndid, int rcvid); + int (*ao_calc_key_sk)(struct tcp_ao_key *mkt, + u8 *key, + const struct sock *sk, + __be32 sisn, __be32 disn, + bool send); #endif }; diff --git a/include/net/tcp_ao.h b/include/net/tcp_ao.h index 73f584b499f6..1172d9d9517a 100644 --- a/include/net/tcp_ao.h +++ b/include/net/tcp_ao.h @@ -95,8 +95,30 @@ struct tcp_ao_info { }; #ifdef CONFIG_TCP_AO +/* TCP-AO structures and functions */ + +struct tcp4_ao_context { + __be32 saddr; + __be32 daddr; + __be16 sport; + __be16 dport; + __be32 sisn; + __be32 disn; +}; + +struct tcp6_ao_context { + struct in6_addr saddr; + struct in6_addr daddr; + __be16 sport; + __be16 dport; + __be32 sisn; + __be32 disn; +}; + int tcp_parse_ao(struct sock *sk, int cmd, unsigned short int family, sockptr_t optval, int optlen); +int tcp_ao_calc_traffic_key(struct tcp_ao_key *mkt, u8 *key, void *ctx, + unsigned int len); void tcp_ao_destroy_sock(struct sock *sk); struct tcp_ao_key *tcp_ao_do_lookup(const struct sock *sk, const union tcp_ao_addr *addr, @@ -105,13 +127,23 @@ struct tcp_ao_key *tcp_ao_do_lookup(const struct sock *sk, int tcp_v4_parse_ao(struct sock *sk, int optname, sockptr_t optval, int optlen); struct tcp_ao_key *tcp_v4_ao_lookup(const struct sock *sk, struct sock *addr_sk, int sndid, int rcvid); +int tcp_v4_ao_calc_key_sk(struct tcp_ao_key *mkt, u8 *key, + const struct sock *sk, + __be32 sisn, __be32 disn, bool send); /* ipv6 specific functions */ +int tcp_v6_ao_calc_key_sk(struct tcp_ao_key *mkt, u8 *key, + const struct sock *sk, __be32 sisn, + __be32 disn, bool send); struct tcp_ao_key *tcp_v6_ao_lookup(const struct sock *sk, struct sock *addr_sk, int sndid, int rcvid); int tcp_v6_parse_ao(struct sock *sk, int cmd, sockptr_t optval, int optlen); -#else +void tcp_ao_finish_connect(struct sock *sk, struct sk_buff *skb); +void tcp_ao_connect_init(struct sock *sk); + +#else /* CONFIG_TCP_AO */ + static inline struct tcp_ao_key *tcp_ao_do_lookup(const struct sock *sk, const union tcp_ao_addr *addr, int family, int sndid, int rcvid, u16 port) @@ -122,6 +154,14 @@ static inline struct tcp_ao_key *tcp_ao_do_lookup(const struct sock *sk, static inline void tcp_ao_destroy_sock(struct sock *sk) { } + +static inline void tcp_ao_finish_connect(struct sock *sk, struct sk_buff *skb) +{ +} + +static inline void tcp_ao_connect_init(struct sock *sk) +{ +} #endif #endif /* _TCP_AO_H */ diff --git a/net/ipv4/tcp_ao.c b/net/ipv4/tcp_ao.c index f12937436377..da0ff96fa3d5 100644 --- a/net/ipv4/tcp_ao.c +++ b/net/ipv4/tcp_ao.c @@ -16,6 +16,42 @@ #include <net/tcp.h> #include <net/ipv6.h> +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 (tcp_sigpool_start(mkt->tcp_sigpool_id, &hp)) + goto clear_hash_noput; + + 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); + + /* TODO: Revisit on how to get different output length */ + ret = crypto_ahash_final(hp.req); + if (ret) + goto clear_hash; + + tcp_sigpool_end(); + return 0; +clear_hash: + tcp_sigpool_end(); +clear_hash_noput: + 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/port/VRF/etc. @@ -172,6 +208,62 @@ void tcp_ao_destroy_sock(struct sock *sk) kfree_rcu(ao, rcu); } +/* 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; + + 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 */ + + return tcp_ao_calc_traffic_key(mkt, key, &tmp, sizeof(tmp)); +} + +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); +} +EXPORT_SYMBOL_GPL(tcp_v4_ao_calc_key_sk); + +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; +} + struct tcp_ao_key *tcp_v4_ao_lookup(const struct sock *sk, struct sock *addr_sk, int sndid, int rcvid) { @@ -180,6 +272,104 @@ struct tcp_ao_key *tcp_v4_ao_lookup(const struct sock *sk, struct sock *addr_sk, return tcp_ao_do_lookup(sk, addr, AF_INET, sndid, rcvid, 0); } +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_ao_info *ao_info; + struct tcp_ao_key *key; + struct tcp_sock *tp = tcp_sk(sk); + union tcp_ao_addr *addr; + 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, sk->sk_dport) == 0) + 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); + tcp_sigpool_release(key->tcp_sigpool_id); + atomic_sub(tcp_ao_sizeof_key(key), &sk->sk_omem_alloc); + kfree_rcu(key, 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); + ao_info->snd_sne = 0; + ao_info->snd_sne_seq = tp->write_seq; + } else { + /* TODO: probably, it should fail to connect() here */ + rcu_assign_pointer(tp->ao_info, NULL); + kfree(ao_info); + } +} + +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; + + ao->risn = tcp_hdr(skb)->seq; + + ao->rcv_sne = 0; + ao->rcv_sne_seq = ntohl(tcp_hdr(skb)->seq); + + hlist_for_each_entry_rcu(key, &ao->head, node) { + tcp_ao_cache_traffic_keys(sk, ao, key); + } +} + static bool tcp_ao_can_set_current_rnext(struct sock *sk) { struct tcp_ao_info *ao_info; @@ -540,6 +730,12 @@ static int tcp_ao_add_cmd(struct sock *sk, unsigned short int family, 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); diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index cc072d2cfcd8..6baeb3fe4352 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -6064,6 +6064,7 @@ void tcp_finish_connect(struct sock *sk, struct sk_buff *skb) struct tcp_sock *tp = tcp_sk(sk); struct inet_connection_sock *icsk = inet_csk(sk); + tcp_ao_finish_connect(sk, skb); tcp_set_state(sk, TCP_ESTABLISHED); icsk->icsk_ack.lrcvtime = tcp_jiffies32; diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index e40baf3e8e29..c03510a24ce0 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -2278,6 +2278,7 @@ static const struct tcp_sock_af_ops tcp_sock_ipv4_specific = { #ifdef CONFIG_TCP_AO .ao_lookup = tcp_v4_ao_lookup, .ao_parse = tcp_v4_parse_ao, + .ao_calc_key_sk = tcp_v4_ao_calc_key_sk, #endif }; #endif diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index 9977e58a5587..260edb2a6b3c 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -3663,6 +3663,7 @@ static void tcp_connect_init(struct sock *sk) if (tp->af_specific->md5_lookup(sk, sk)) tp->tcp_header_len += TCPOLEN_MD5SIG_ALIGNED; #endif + tcp_ao_connect_init(sk); /* If user gave his TCP_MAXSEG, record it to clamp */ if (tp->rx_opt.user_mss) diff --git a/net/ipv6/tcp_ao.c b/net/ipv6/tcp_ao.c index 3d2be5f73cf0..2be0103fc4f8 100644 --- a/net/ipv6/tcp_ao.c +++ b/net/ipv6/tcp_ao.c @@ -12,6 +12,46 @@ #include <net/tcp.h> #include <net/ipv6.h> +static int 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 tmp; + + 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 */ + + return tcp_ao_calc_traffic_key(mkt, key, &tmp, sizeof(tmp)); +} + +int 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) + return 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 + return 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); +} + struct tcp_ao_key *tcp_v6_ao_do_lookup(const struct sock *sk, const struct in6_addr *addr, int sndid, int rcvid) diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c index 93ee479814bb..4e48818c1821 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -1918,6 +1918,7 @@ static const struct tcp_sock_af_ops tcp_sock_ipv6_specific = { #ifdef CONFIG_TCP_AO .ao_lookup = tcp_v6_ao_lookup, .ao_parse = tcp_v6_parse_ao, + .ao_calc_key_sk = tcp_v6_ao_calc_key_sk, #endif }; #endif

[v5,05/21] net/tcp: Calculate TCP-AO traffic keys

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