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Miller" , linux-kernel@vger.kernel.org Cc: Dmitry Safonov , Andy Lutomirski , Ard Biesheuvel , Bob Gilligan , David Ahern , Dmitry Safonov <0x7f454c46@gmail.com>, Eric Biggers , Francesco Ruggeri , Herbert Xu , Hideaki YOSHIFUJI , Ivan Delalande , Jakub Kicinski , Leonard Crestez , Paolo Abeni , Salam Noureddine , Shuah Khan , netdev@vger.kernel.org, linux-crypto@vger.kernel.org Subject: [PATCH 16/31] net/tcp: Sign SYN-ACK segments with TCP-AO Date: Thu, 18 Aug 2022 17:59:50 +0100 Message-Id: <20220818170005.747015-17-dima@arista.com> X-Mailer: git-send-email 2.37.2 In-Reply-To: <20220818170005.747015-1-dima@arista.com> References: <20220818170005.747015-1-dima@arista.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org Similarly to RST segments, wire SYN-ACKs to TCP-AO. tcp_rsk_used_ao() is handy here to check if the request socket used AO and needs a signature on the outgoing segments. 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 | 4 ++++ include/net/tcp_ao.h | 6 ++++++ net/ipv4/tcp_ao.c | 14 ++++++++++++++ net/ipv4/tcp_ipv4.c | 1 + net/ipv4/tcp_output.c | 37 +++++++++++++++++++++++++++++++------ net/ipv6/tcp_ao.c | 14 ++++++++++++++ net/ipv6/tcp_ipv6.c | 1 + 7 files changed, 71 insertions(+), 6 deletions(-) diff --git a/include/net/tcp.h b/include/net/tcp.h index f21898bb31bd..19549be29265 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -2109,6 +2109,10 @@ struct tcp_request_sock_ops { int sndid, int rcvid); int (*ao_calc_key)(struct tcp_ao_key *mkt, u8 *key, struct request_sock *sk); + int (*ao_synack_hash)(char *ao_hash, struct tcp_ao_key *mkt, + struct request_sock *req, + const struct sk_buff *skb, + int hash_offset, u32 sne); #endif #ifdef CONFIG_SYN_COOKIES __u32 (*cookie_init_seq)(const struct sk_buff *skb, diff --git a/include/net/tcp_ao.h b/include/net/tcp_ao.h index a1d26e1a0b82..cc3f6686d5c9 100644 --- a/include/net/tcp_ao.h +++ b/include/net/tcp_ao.h @@ -142,6 +142,9 @@ int tcp_ao_hash_hdr(unsigned short family, char *ao_hash, 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_synack_hash(char *ao_hash, struct tcp_ao_key *mkt, + struct request_sock *req, const struct sk_buff *skb, + int hash_offset, u32 sne); int tcp_v4_ao_calc_key_sk(struct tcp_ao_key *mkt, u8 *key, const struct sock *sk, __be32 sisn, __be32 disn, bool send); @@ -176,6 +179,9 @@ int tcp_v6_ao_hash_skb(char *ao_hash, struct tcp_ao_key *key, const u8 *tkey, int hash_offset, u32 sne); int tcp_v6_parse_ao(struct sock *sk, int cmd, sockptr_t optval, int 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); void tcp_ao_finish_connect(struct sock *sk, struct sk_buff *skb); void tcp_ao_connect_init(struct sock *sk); diff --git a/net/ipv4/tcp_ao.c b/net/ipv4/tcp_ao.c index a797eedfbcdf..78c24ade9a03 100644 --- a/net/ipv4/tcp_ao.c +++ b/net/ipv4/tcp_ao.c @@ -586,6 +586,20 @@ int tcp_v4_ao_hash_skb(char *ao_hash, struct tcp_ao_key *key, 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) +{ + char traffic_key[TCP_AO_MAX_HASH_SIZE] __tcp_ao_key_align; + + tcp_v4_ao_calc_key_rsk(ao_key, traffic_key, req); + + tcp_ao_hash_skb(AF_INET, ao_hash, ao_key, req_to_sk(req), skb, + traffic_key, hash_offset, sne); + + return 0; +} + struct tcp_ao_key *tcp_v4_ao_lookup_rsk(const struct sock *sk, struct request_sock *req, int sndid, int rcvid) diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index 55c763b8bf24..02ab94461e86 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -1649,6 +1649,7 @@ const struct tcp_request_sock_ops tcp_request_sock_ipv4_ops = { #ifdef CONFIG_TCP_AO .ao_lookup = tcp_v4_ao_lookup_rsk, .ao_calc_key = tcp_v4_ao_calc_key_rsk, + .ao_synack_hash = tcp_v4_ao_synack_hash, #endif #ifdef CONFIG_SYN_COOKIES .cookie_init_seq = cookie_v4_init_sequence, diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index 81f897f95147..43111e39b6e1 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -3630,6 +3630,7 @@ struct sk_buff *tcp_make_synack(const struct sock *sk, struct dst_entry *dst, struct inet_request_sock *ireq = inet_rsk(req); const struct tcp_sock *tp = tcp_sk(sk); struct tcp_md5sig_key *md5 = NULL; + struct tcp_ao_key *ao_key = NULL; struct tcp_out_options opts; struct sk_buff *skb; int tcp_header_size; @@ -3680,16 +3681,32 @@ struct sk_buff *tcp_make_synack(const struct sock *sk, struct dst_entry *dst, tcp_rsk(req)->snt_synack = tcp_skb_timestamp_us(skb); } -#ifdef CONFIG_TCP_MD5SIG +#if defined(CONFIG_TCP_MD5SIG) || defined(CONFIG_TCP_AO) rcu_read_lock(); - md5 = tcp_rsk(req)->af_specific->req_md5_lookup(sk, req_to_sk(req)); #endif + if (tcp_rsk_used_ao(req)) { +#ifdef CONFIG_TCP_AO + /* TODO: what should we do if the key is no longer available on + * the listening socket? Maybe we can try a different matching + * key (without sndid match). If that also fails what should + * we do? We currently send an unsigned synack. It's probably + * better to not send anything. + */ + ao_key = tcp_sk(sk)->af_specific->ao_lookup(sk, req_to_sk(req), + tcp_rsk(req)->ao_keyid, -1); +#endif + } else { +#ifdef CONFIG_TCP_MD5SIG + md5 = tcp_rsk(req)->af_specific->req_md5_lookup(sk, + req_to_sk(req)); +#endif + } skb_set_hash(skb, tcp_rsk(req)->txhash, PKT_HASH_TYPE_L4); /* bpf program will be interested in the tcp_flags */ TCP_SKB_CB(skb)->tcp_flags = TCPHDR_SYN | TCPHDR_ACK; tcp_header_size = tcp_synack_options(sk, req, mss, skb, &opts, md5, - NULL, foc, synack_type, - syn_skb) + sizeof(*th); + ao_key, foc, synack_type, syn_skb) + + sizeof(*th); skb_push(skb, tcp_header_size); skb_reset_transport_header(skb); @@ -3709,7 +3726,7 @@ struct sk_buff *tcp_make_synack(const struct sock *sk, struct dst_entry *dst, /* RFC1323: The window in SYN & SYN/ACK segments is never scaled. */ th->window = htons(min(req->rsk_rcv_wnd, 65535U)); - tcp_options_write(th, NULL, NULL, &opts, NULL); + tcp_options_write(th, NULL, tcp_rsk(req), &opts, NULL); th->doff = (tcp_header_size >> 2); __TCP_INC_STATS(sock_net(sk), TCP_MIB_OUTSEGS); @@ -3717,7 +3734,15 @@ struct sk_buff *tcp_make_synack(const struct sock *sk, struct dst_entry *dst, /* Okay, we have all we need - do the md5 hash if needed */ if (md5) tcp_rsk(req)->af_specific->calc_md5_hash(opts.hash_location, - md5, req_to_sk(req), skb); + md5, req_to_sk(req), skb); +#endif +#ifdef CONFIG_TCP_AO + if (ao_key) + tcp_rsk(req)->af_specific->ao_synack_hash(opts.hash_location, + ao_key, req, skb, + opts.hash_location - (u8 *)th, 0); +#endif +#if defined(CONFIG_TCP_MD5SIG) || defined(CONFIG_TCP_AO) rcu_read_unlock(); #endif diff --git a/net/ipv6/tcp_ao.c b/net/ipv6/tcp_ao.c index 31ae504af8e6..526bbe232a64 100644 --- a/net/ipv6/tcp_ao.c +++ b/net/ipv6/tcp_ao.c @@ -123,3 +123,17 @@ int tcp_v6_parse_ao(struct sock *sk, int cmd, { 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) +{ + char traffic_key[TCP_AO_MAX_HASH_SIZE] __tcp_ao_key_align; + + tcp_v6_ao_calc_key_rsk(ao_key, traffic_key, req); + + tcp_ao_hash_skb(AF_INET6, ao_hash, ao_key, req_to_sk(req), skb, + traffic_key, hash_offset, sne); + + return 0; +} diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c index 7610fdf5d519..16cea7de0851 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -838,6 +838,7 @@ const struct tcp_request_sock_ops tcp_request_sock_ipv6_ops = { #ifdef CONFIG_TCP_AO .ao_lookup = tcp_v6_ao_lookup_rsk, .ao_calc_key = tcp_v6_ao_calc_key_rsk, + .ao_synack_hash = tcp_v6_ao_synack_hash, #endif #ifdef CONFIG_SYN_COOKIES .cookie_init_seq = cookie_v6_init_sequence,