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Miller" Cc: linux-kernel@vger.kernel.org, Dmitry Safonov , Andy Lutomirski , Ard Biesheuvel , Bob Gilligan , Dan Carpenter , David Laight , Dmitry Safonov <0x7f454c46@gmail.com>, Donald Cassidy , Eric Biggers , "Eric W. Biederman" , Francesco Ruggeri , "Gaillardetz, Dominik" , Herbert Xu , Hideaki YOSHIFUJI , Ivan Delalande , Leonard Crestez , Salam Noureddine , "Tetreault, Francois" , netdev@vger.kernel.org Subject: [PATCH v8.1 net-next 05/23] net/tcp: Calculate TCP-AO traffic keys Date: Fri, 21 Jul 2023 17:18:56 +0100 Message-ID: <20230721161916.542667-6-dima@arista.com> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230721161916.542667-1-dima@arista.com> References: <20230721161916.542667-1-dima@arista.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF, RCVD_IN_DNSWL_BLOCKED,SPF_HELO_NONE,SPF_NONE,T_SCC_BODY_TEXT_LINE, URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net X-Patchwork-Delegate: kuba@kernel.org Add traffic key calculation the way it's described in RFC5926. Wire it up to tcp_finish_connect() and cache the new keys straight away on already established TCP connections. Co-developed-by: Francesco Ruggeri Signed-off-by: Francesco Ruggeri Co-developed-by: Salam Noureddine Signed-off-by: Salam Noureddine Signed-off-by: Dmitry Safonov --- include/net/tcp.h | 5 ++ include/net/tcp_ao.h | 43 +++++++++- net/ipv4/tcp_ao.c | 191 ++++++++++++++++++++++++++++++++++++++++++ net/ipv4/tcp_input.c | 1 + net/ipv4/tcp_ipv4.c | 1 + net/ipv4/tcp_output.c | 1 + net/ipv6/tcp_ao.c | 50 +++++++++++ net/ipv6/tcp_ipv6.c | 1 + 8 files changed, 292 insertions(+), 1 deletion(-) diff --git a/include/net/tcp.h b/include/net/tcp.h index 7e414873ef07..6a2e15a94214 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -2147,6 +2147,11 @@ 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 1c24b586c876..1aac82c1d22d 100644 --- a/include/net/tcp_ao.h +++ b/include/net/tcp_ao.h @@ -90,8 +90,31 @@ 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; +}; +struct tcp_sigpool; + 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, struct tcp_sigpool *hp); 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, @@ -100,13 +123,23 @@ 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) @@ -117,6 +150,14 @@ 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 c2be72beab70..a5c70cbaa954 100644 --- a/net/ipv4/tcp_ao.c +++ b/net/ipv4/tcp_ao.c @@ -16,6 +16,34 @@ #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/port/VRF/etc. @@ -171,6 +199,71 @@ 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; + 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; +} + struct tcp_ao_key *tcp_v4_ao_lookup(const struct sock *sk, struct sock *addr_sk, int sndid, int rcvid) { @@ -179,6 +272,98 @@ 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); + } 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; + + 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) { /* There aren't current/rnext keys on TCP_LISTEN sockets */ @@ -576,6 +761,12 @@ 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 670c3dab24f2..7780ceef3415 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -6082,6 +6082,7 @@ 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 65e9bcac45f9..447e0c6f132f 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -2286,6 +2286,7 @@ 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 e98083abd7fb..937516aac99a 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -3745,6 +3745,7 @@ 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 a56ab0a9cf55..0b490738c366 100644 --- a/net/ipv6/tcp_ao.c +++ b/net/ipv6/tcp_ao.c @@ -12,6 +12,56 @@ #include #include +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; + 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_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 5c7c9dbfdb73..1e67aaf42460 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -1917,6 +1917,7 @@ 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