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Message-ID: <20231121020111.1143180-8-dima@arista.com> Date: Tue, 21 Nov 2023 02:01:11 +0000 From: Dmitry Safonov <dima@...sta.com> To: David Ahern <dsahern@...nel.org>, Eric Dumazet <edumazet@...gle.com>, Paolo Abeni <pabeni@...hat.com>, Jakub Kicinski <kuba@...nel.org>, "David S. Miller" <davem@...emloft.net> Cc: linux-kernel@...r.kernel.org, Dmitry Safonov <dima@...sta.com>, Dmitry Safonov <0x7f454c46@...il.com>, Francesco Ruggeri <fruggeri05@...il.com>, Salam Noureddine <noureddine@...sta.com>, Simon Horman <horms@...nel.org>, netdev@...r.kernel.org Subject: [PATCH 7/7] net/tcp: Don't store TCP-AO maclen on reqsk This extra check doesn't work for a handshake when SYN segment has (current_key.maclen != rnext_key.maclen). It could be amended to preserve rnext_key.maclen instead of current_key.maclen, but that requires a lookup on listen socket. Originally, this extra maclen check was introduced just because it was cheap. Drop it and convert tcp_request_sock::maclen into boolean tcp_request_sock::used_tcp_ao. Fixes: 06b22ef29591 ("net/tcp: Wire TCP-AO to request sockets") Signed-off-by: Dmitry Safonov <dima@...sta.com> --- include/linux/tcp.h | 10 ++++------ net/ipv4/tcp_ao.c | 4 ++-- net/ipv4/tcp_input.c | 5 +++-- net/ipv4/tcp_output.c | 9 +++------ 4 files changed, 12 insertions(+), 16 deletions(-) diff --git a/include/linux/tcp.h b/include/linux/tcp.h index 68f3d315d2e1..3af897b00920 100644 --- a/include/linux/tcp.h +++ b/include/linux/tcp.h @@ -155,6 +155,9 @@ struct tcp_request_sock { bool req_usec_ts; #if IS_ENABLED(CONFIG_MPTCP) bool drop_req; +#endif +#ifdef CONFIG_TCP_AO + bool used_tcp_ao; #endif u32 txhash; u32 rcv_isn; @@ -169,7 +172,6 @@ struct tcp_request_sock { #ifdef CONFIG_TCP_AO u8 ao_keyid; u8 ao_rcv_next; - u8 maclen; #endif }; @@ -180,14 +182,10 @@ static inline struct tcp_request_sock *tcp_rsk(const struct request_sock *req) static inline bool tcp_rsk_used_ao(const struct request_sock *req) { - /* The real length of MAC is saved in the request socket, - * signing anything with zero-length makes no sense, so here is - * a little hack.. - */ #ifndef CONFIG_TCP_AO return false; #else - return tcp_rsk(req)->maclen != 0; + return tcp_rsk(req)->used_tcp_ao; #endif } diff --git a/net/ipv4/tcp_ao.c b/net/ipv4/tcp_ao.c index 9b7f1970c2e9..07221319e8c5 100644 --- a/net/ipv4/tcp_ao.c +++ b/net/ipv4/tcp_ao.c @@ -851,7 +851,7 @@ void tcp_ao_syncookie(struct sock *sk, const struct sk_buff *skb, const struct tcp_ao_hdr *aoh; struct tcp_ao_key *key; - treq->maclen = 0; + treq->used_tcp_ao = false; if (tcp_parse_auth_options(th, NULL, &aoh) || !aoh) return; @@ -863,7 +863,7 @@ void tcp_ao_syncookie(struct sock *sk, const struct sk_buff *skb, treq->ao_rcv_next = aoh->keyid; treq->ao_keyid = aoh->rnext_keyid; - treq->maclen = tcp_ao_maclen(key); + treq->used_tcp_ao = true; } static enum skb_drop_reason diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index 78896c8be0d4..89cb6912dd91 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -7182,11 +7182,12 @@ int tcp_conn_request(struct request_sock_ops *rsk_ops, if (tcp_parse_auth_options(tcp_hdr(skb), NULL, &aoh)) goto drop_and_release; /* Invalid TCP options */ if (aoh) { - tcp_rsk(req)->maclen = aoh->length - sizeof(struct tcp_ao_hdr); + tcp_rsk(req)->used_tcp_ao = true; tcp_rsk(req)->ao_rcv_next = aoh->keyid; tcp_rsk(req)->ao_keyid = aoh->rnext_keyid; + } else { - tcp_rsk(req)->maclen = 0; + tcp_rsk(req)->used_tcp_ao = false; } #endif tcp_rsk(req)->snt_isn = isn; diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index 93eef1dbbc55..f5ef15e1d9ac 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -3720,7 +3720,6 @@ struct sk_buff *tcp_make_synack(const struct sock *sk, struct dst_entry *dst, if (tcp_rsk_used_ao(req)) { #ifdef CONFIG_TCP_AO struct tcp_ao_key *ao_key = NULL; - 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), @@ -3730,13 +3729,11 @@ struct sk_buff *tcp_make_synack(const struct sock *sk, struct dst_entry *dst, * 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)) { - u8 key_maclen = ao_key ? tcp_ao_maclen(ao_key) : 0; - + if (unlikely(!ao_key)) { rcu_read_unlock(); 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, key_maclen); + net_warn_ratelimited("TCP-AO: the keyid %u from SYN packet is not present - not sending SYNACK\n", + keyid); return NULL; } key.ao_key = ao_key; -- 2.42.0
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