[v7,11/22] net/tcp: Sign SYN-ACK segments with TCP-AO

Message ID	20230614230947.3954084-12-dima@arista.com (mailing list archive)
State	Changes Requested
Delegated to:	Netdev Maintainers
Headers	show Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6827D18AFB for <netdev@vger.kernel.org>; Wed, 14 Jun 2023 23:10:30 +0000 (UTC) From: Dmitry Safonov <dima@arista.com> To: 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: linux-kernel@vger.kernel.org, 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>, Donald Cassidy <dcassidy@redhat.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 Subject: [PATCH v7 11/22] net/tcp: Sign SYN-ACK segments with TCP-AO Date: Thu, 15 Jun 2023 00:09:36 +0100 Message-Id: <20230614230947.3954084-12-dima@arista.com> In-Reply-To: <20230614230947.3954084-1-dima@arista.com> References: <20230614230947.3954084-1-dima@arista.com> Precedence: bulk MIME-Version: 1.0 Content-Transfer-Encoding: 8bit
Series	net/tcp: Add TCP-AO support \| expand [v7,00/22] net/tcp: Add TCP-AO support [v7,01/22] net/tcp: Prepare tcp_md5sig_pool for TCP-AO [v7,02/22] net/tcp: Add TCP-AO config and structures [v7,03/22] net/tcp: Introduce TCP_AO setsockopt()s [v7,04/22] net/tcp: Prevent TCP-MD5 with TCP-AO being set [v7,05/22] net/tcp: Calculate TCP-AO traffic keys [v7,06/22] net/tcp: Add TCP-AO sign to outgoing packets [v7,07/22] net/tcp: Add tcp_parse_auth_options() [v7,08/22] net/tcp: Add AO sign to RST packets [v7,09/22] net/tcp: Add TCP-AO sign to twsk [v7,10/22] net/tcp: Wire TCP-AO to request sockets [v7,11/22] net/tcp: Sign SYN-ACK segments with TCP-AO [v7,12/22] net/tcp: Verify inbound TCP-AO signed segments [v7,13/22] net/tcp: Add TCP-AO segments counters [v7,14/22] net/tcp: Add TCP-AO SNE support [v7,15/22] net/tcp: Add tcp_hash_fail() ratelimited logs [v7,16/22] net/tcp: Ignore specific ICMPs for TCP-AO connections [v7,17/22] net/tcp: Add option for TCP-AO to (not) hash header [v7,18/22] net/tcp: Add TCP-AO getsockopt()s [v7,19/22] net/tcp: Allow asynchronous delete for TCP-AO keys (MKTs) [v7,20/22] net/tcp: Add static_key for TCP-AO [v7,21/22] net/tcp: Wire up l3index to TCP-AO [v7,22/22] net/tcp: Add TCP_AO_REPAIR

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 f80e99fc1922..1d38ecac9b00 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -2151,6 +2151,10 @@ 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 02a15aa6650f..933b39445575 100644 --- a/include/net/tcp_ao.h +++ b/include/net/tcp_ao.h @@ -149,6 +149,9 @@ int tcp_ao_prepare_reset(const struct sock *sk, struct sk_buff *skb, 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); @@ -184,6 +187,9 @@ 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); void tcp_ao_syncookie(struct sock *sk, const struct sk_buff *skb, diff --git a/net/ipv4/tcp_ao.c b/net/ipv4/tcp_ao.c index d3e916d2ed98..a22d6321bc81 100644 --- a/net/ipv4/tcp_ao.c +++ b/net/ipv4/tcp_ao.c @@ -554,6 +554,20 @@ int tcp_v4_ao_hash_skb(char *ao_hash, struct tcp_ao_key *key, } EXPORT_SYMBOL_GPL(tcp_v4_ao_hash_skb); +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 1d78853ec07c..97712b954e2d 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -1673,6 +1673,7 @@ 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 5344e6564b56..f055ef225c37 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -3638,6 +3638,7 @@ 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; @@ -3688,16 +3689,43 @@ 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 + u8 maclen = tcp_rsk(req)->maclen; + u8 keyid = tcp_rsk(req)->ao_keyid; + + ao_key = tcp_sk(sk)->af_specific->ao_lookup(sk, req_to_sk(req), + keyid, -1); + /* If there is no matching key - avoid sending anything, + * especially usigned segments. It could try harder and lookup + * for another peer-matching key, but the peer has requested + * ao_keyid (RFC5925 RNextKeyID), so let's keep it simple here. + */ + if (unlikely(!ao_key || tcp_ao_maclen(ao_key) != maclen)) { + rcu_read_unlock(); + skb_dst_drop(skb); + kfree_skb(skb); + net_warn_ratelimited("TCP-AO: the keyid %u with maclen %u|%u from SYN packet is not present - not sending SYNACK\n", + keyid, maclen, + ao_key ? tcp_ao_maclen(ao_key) : 0); + return NULL; + } +#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); @@ -3717,7 +3745,7 @@ 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, ao_key); th->doff = (tcp_header_size >> 2); TCP_INC_STATS(sock_net(sk), TCP_MIB_OUTSEGS); @@ -3725,7 +3753,15 @@ 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 17acb2fd5182..bc032e441ef8 100644 --- a/net/ipv6/tcp_ao.c +++ b/net/ipv6/tcp_ao.c @@ -128,3 +128,18 @@ int tcp_v6_parse_ao(struct sock *sk, int cmd, return tcp_parse_ao(sk, cmd, AF_INET6, optval, optlen); } EXPORT_SYMBOL_GPL(tcp_v6_parse_ao); + +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; +} +EXPORT_SYMBOL_GPL(tcp_v6_ao_synack_hash); diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c index a7efec5af4e6..19f644970196 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -849,6 +849,7 @@ 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,

[v7,11/22] net/tcp: Sign SYN-ACK segments with TCP-AO

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