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Message-ID: <20231004223629.166300-21-dima@arista.com> Date: Wed, 4 Oct 2023 23:36:24 +0100 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>, Andy Lutomirski <luto@...capital.net>, Ard Biesheuvel <ardb@...nel.org>, Bob Gilligan <gilligan@...sta.com>, Dan Carpenter <error27@...il.com>, David Laight <David.Laight@...lab.com>, Dmitry Safonov <0x7f454c46@...il.com>, Donald Cassidy <dcassidy@...hat.com>, Eric Biggers <ebiggers@...nel.org>, "Eric W. Biederman" <ebiederm@...ssion.com>, Francesco Ruggeri <fruggeri05@...il.com>, "Gaillardetz, Dominik" <dgaillar@...na.com>, Herbert Xu <herbert@...dor.apana.org.au>, Hideaki YOSHIFUJI <yoshfuji@...ux-ipv6.org>, Ivan Delalande <colona@...sta.com>, Leonard Crestez <cdleonard@...il.com>, "Nassiri, Mohammad" <mnassiri@...na.com>, Salam Noureddine <noureddine@...sta.com>, Simon Horman <simon.horman@...igine.com>, "Tetreault, Francois" <ftetreau@...na.com>, netdev@...r.kernel.org Subject: [PATCH v13 net-next 20/23] net/tcp: Add static_key for TCP-AO Similarly to TCP-MD5, add a static key to TCP-AO that is patched out when there are no keys on a machine and dynamically enabled with the first setsockopt(TCP_AO) adds a key on any socket. The static key is as well dynamically disabled later when the socket is destructed. The lifetime of enabled static key here is the same as ao_info: it is enabled on allocation, passed over from full socket to twsk and destructed when ao_info is scheduled for destruction. Signed-off-by: Dmitry Safonov <dima@...sta.com> Acked-by: David Ahern <dsahern@...nel.org> --- include/net/tcp.h | 24 +++++++++++++++-------- include/net/tcp_ao.h | 2 ++ net/ipv4/tcp_ao.c | 22 +++++++++++++++++++++ net/ipv4/tcp_input.c | 46 +++++++++++++++++++++++++++++--------------- net/ipv4/tcp_ipv4.c | 25 +++++++++++++----------- net/ipv6/tcp_ipv6.c | 25 +++++++++++++----------- 6 files changed, 98 insertions(+), 46 deletions(-) diff --git a/include/net/tcp.h b/include/net/tcp.h index d91ddeca1652..5215f4ff4a1c 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -2248,14 +2248,18 @@ static inline void tcp_get_current_key(const struct sock *sk, #if defined(CONFIG_TCP_AO) || defined(CONFIG_TCP_MD5SIG) const struct tcp_sock *tp = tcp_sk(sk); #endif -#ifdef CONFIG_TCP_AO - struct tcp_ao_info *ao; - ao = rcu_dereference_protected(tp->ao_info, lockdep_sock_is_held(sk)); - if (ao) { - out->ao_key = READ_ONCE(ao->current_key); - out->type = TCP_KEY_AO; - return; +#ifdef CONFIG_TCP_AO + if (static_branch_unlikely(&tcp_ao_needed.key)) { + struct tcp_ao_info *ao; + + ao = rcu_dereference_protected(tp->ao_info, + lockdep_sock_is_held(sk)); + if (ao) { + out->ao_key = READ_ONCE(ao->current_key); + out->type = TCP_KEY_AO; + return; + } } #endif #ifdef CONFIG_TCP_MD5SIG @@ -2284,7 +2288,8 @@ static inline bool tcp_key_is_md5(const struct tcp_key *key) static inline bool tcp_key_is_ao(const struct tcp_key *key) { #ifdef CONFIG_TCP_AO - if (key->type == TCP_KEY_AO) + if (static_branch_unlikely(&tcp_ao_needed.key) && + key->type == TCP_KEY_AO) return true; #endif return false; @@ -2678,6 +2683,9 @@ static inline bool tcp_ao_required(struct sock *sk, const void *saddr, struct tcp_ao_info *ao_info; struct tcp_ao_key *ao_key; + if (!static_branch_unlikely(&tcp_ao_needed.key)) + return false; + ao_info = rcu_dereference_check(tcp_sk(sk)->ao_info, lockdep_sock_is_held(sk)); if (!ao_info) diff --git a/include/net/tcp_ao.h b/include/net/tcp_ao.h index 746bf078e59c..ba5b8c409e99 100644 --- a/include/net/tcp_ao.h +++ b/include/net/tcp_ao.h @@ -151,6 +151,8 @@ do { \ #ifdef CONFIG_TCP_AO /* TCP-AO structures and functions */ +#include <linux/jump_label.h> +extern struct static_key_false_deferred tcp_ao_needed; struct tcp4_ao_context { __be32 saddr; diff --git a/net/ipv4/tcp_ao.c b/net/ipv4/tcp_ao.c index afd5943a9972..9e8016157a37 100644 --- a/net/ipv4/tcp_ao.c +++ b/net/ipv4/tcp_ao.c @@ -17,6 +17,8 @@ #include <net/ipv6.h> #include <net/icmp.h> +DEFINE_STATIC_KEY_DEFERRED_FALSE(tcp_ao_needed, HZ); + int tcp_ao_calc_traffic_key(struct tcp_ao_key *mkt, u8 *key, void *ctx, unsigned int len, struct tcp_sigpool *hp) { @@ -50,6 +52,9 @@ bool tcp_ao_ignore_icmp(const struct sock *sk, int type, int code) bool ignore_icmp = false; struct tcp_ao_info *ao; + if (!static_branch_unlikely(&tcp_ao_needed.key)) + return false; + /* RFC5925, 7.8: * >> A TCP-AO implementation MUST default to ignore incoming ICMPv4 * messages of Type 3 (destination unreachable), Codes 2-4 (protocol @@ -185,6 +190,9 @@ static struct tcp_ao_key *__tcp_ao_do_lookup(const struct sock *sk, struct tcp_ao_key *key; struct tcp_ao_info *ao; + if (!static_branch_unlikely(&tcp_ao_needed.key)) + return NULL; + ao = rcu_dereference_check(tcp_sk(sk)->ao_info, lockdep_sock_is_held(sk)); if (!ao) @@ -276,6 +284,7 @@ void tcp_ao_destroy_sock(struct sock *sk, bool twsk) } kfree_rcu(ao, rcu); + static_branch_slow_dec_deferred(&tcp_ao_needed); } void tcp_ao_time_wait(struct tcp_timewait_sock *tcptw, struct tcp_sock *tp) @@ -1177,6 +1186,11 @@ int tcp_ao_copy_all_matching(const struct sock *sk, struct sock *newsk, goto free_and_exit; } + if (!static_key_fast_inc_not_disabled(&tcp_ao_needed.key.key)) { + ret = -EUSERS; + goto free_and_exit; + } + key_head = rcu_dereference(hlist_first_rcu(&new_ao->head)); first_key = hlist_entry_safe(key_head, struct tcp_ao_key, node); @@ -1604,6 +1618,10 @@ static int tcp_ao_add_cmd(struct sock *sk, unsigned short int family, tcp_ao_link_mkt(ao_info, key); if (first) { + if (!static_branch_inc(&tcp_ao_needed.key)) { + ret = -EUSERS; + goto err_free_sock; + } sk_gso_disable(sk); rcu_assign_pointer(tcp_sk(sk)->ao_info, ao_info); } @@ -1872,6 +1890,10 @@ static int tcp_ao_info_cmd(struct sock *sk, unsigned short int family, if (new_rnext) WRITE_ONCE(ao_info->rnext_key, new_rnext); if (first) { + if (!static_branch_inc(&tcp_ao_needed.key)) { + err = -EUSERS; + goto out; + } sk_gso_disable(sk); rcu_assign_pointer(tcp_sk(sk)->ao_info, ao_info); } diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index 2ce768e1d914..e432b6da1135 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -3542,41 +3542,55 @@ static inline bool tcp_may_update_window(const struct tcp_sock *tp, (ack_seq == tp->snd_wl1 && (nwin > tp->snd_wnd || !nwin)); } -/* If we update tp->snd_una, also update tp->bytes_acked */ -static void tcp_snd_una_update(struct tcp_sock *tp, u32 ack) +static void tcp_snd_sne_update(struct tcp_sock *tp, u32 ack) { - u32 delta = ack - tp->snd_una; #ifdef CONFIG_TCP_AO struct tcp_ao_info *ao; -#endif - sock_owned_by_me((struct sock *)tp); - tp->bytes_acked += delta; -#ifdef CONFIG_TCP_AO + if (!static_branch_unlikely(&tcp_ao_needed.key)) + return; + ao = rcu_dereference_protected(tp->ao_info, lockdep_sock_is_held((struct sock *)tp)); if (ao && ack < tp->snd_una) ao->snd_sne++; #endif +} + +/* If we update tp->snd_una, also update tp->bytes_acked */ +static void tcp_snd_una_update(struct tcp_sock *tp, u32 ack) +{ + u32 delta = ack - tp->snd_una; + + sock_owned_by_me((struct sock *)tp); + tp->bytes_acked += delta; + tcp_snd_sne_update(tp, ack); tp->snd_una = ack; } +static void tcp_rcv_sne_update(struct tcp_sock *tp, u32 seq) +{ +#ifdef CONFIG_TCP_AO + struct tcp_ao_info *ao; + + if (!static_branch_unlikely(&tcp_ao_needed.key)) + return; + + ao = rcu_dereference_protected(tp->ao_info, + lockdep_sock_is_held((struct sock *)tp)); + if (ao && seq < tp->rcv_nxt) + ao->rcv_sne++; +#endif +} + /* If we update tp->rcv_nxt, also update tp->bytes_received */ static void tcp_rcv_nxt_update(struct tcp_sock *tp, u32 seq) { u32 delta = seq - tp->rcv_nxt; -#ifdef CONFIG_TCP_AO - struct tcp_ao_info *ao; -#endif sock_owned_by_me((struct sock *)tp); tp->bytes_received += delta; -#ifdef CONFIG_TCP_AO - ao = rcu_dereference_protected(tp->ao_info, - lockdep_sock_is_held((struct sock *)tp)); - if (ao && seq < tp->rcv_nxt) - ao->rcv_sne++; -#endif + tcp_rcv_sne_update(tp, seq); WRITE_ONCE(tp->rcv_nxt, seq); } diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index 772fc6347302..cb314a28010f 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -1023,18 +1023,20 @@ static void tcp_v4_timewait_ack(struct sock *sk, struct sk_buff *skb) #ifdef CONFIG_TCP_AO struct tcp_ao_info *ao_info; - /* FIXME: the segment to-be-acked is not verified yet */ - ao_info = rcu_dereference(tcptw->ao_info); - if (ao_info) { - const struct tcp_ao_hdr *aoh; + if (static_branch_unlikely(&tcp_ao_needed.key)) { + /* FIXME: the segment to-be-acked is not verified yet */ + ao_info = rcu_dereference(tcptw->ao_info); + if (ao_info) { + const struct tcp_ao_hdr *aoh; - if (tcp_parse_auth_options(tcp_hdr(skb), NULL, &aoh)) { - inet_twsk_put(tw); - return; + if (tcp_parse_auth_options(tcp_hdr(skb), NULL, &aoh)) { + inet_twsk_put(tw); + return; + } + + if (aoh) + key.ao_key = tcp_ao_established_key(ao_info, aoh->rnext_keyid, -1); } - - if (aoh) - key.ao_key = tcp_ao_established_key(ao_info, aoh->rnext_keyid, -1); } if (key.ao_key) { struct tcp_ao_key *rnext_key; @@ -1080,7 +1082,8 @@ static void tcp_v4_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb, tcp_sk(sk)->snd_nxt; #ifdef CONFIG_TCP_AO - if (tcp_rsk_used_ao(req)) { + if (static_branch_unlikely(&tcp_ao_needed.key) && + tcp_rsk_used_ao(req)) { const union tcp_md5_addr *addr; const struct tcp_ao_hdr *aoh; diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c index 7ae70d6db07d..e71708dc011c 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -1151,17 +1151,19 @@ static void tcp_v6_timewait_ack(struct sock *sk, struct sk_buff *skb) #ifdef CONFIG_TCP_AO struct tcp_ao_info *ao_info; - /* FIXME: the segment to-be-acked is not verified yet */ - ao_info = rcu_dereference(tcptw->ao_info); - if (ao_info) { - const struct tcp_ao_hdr *aoh; + if (static_branch_unlikely(&tcp_ao_needed.key)) { - /* Invalid TCP option size or twice included auth */ - if (tcp_parse_auth_options(tcp_hdr(skb), NULL, &aoh)) - goto out; - if (aoh) { - key.ao_key = tcp_ao_established_key(ao_info, - aoh->rnext_keyid, -1); + /* FIXME: the segment to-be-acked is not verified yet */ + ao_info = rcu_dereference(tcptw->ao_info); + if (ao_info) { + const struct tcp_ao_hdr *aoh; + + /* Invalid TCP option size or twice included auth */ + if (tcp_parse_auth_options(tcp_hdr(skb), NULL, &aoh)) + goto out; + if (aoh) + key.ao_key = tcp_ao_established_key(ao_info, + aoh->rnext_keyid, -1); } } if (key.ao_key) { @@ -1203,7 +1205,8 @@ static void tcp_v6_reqsk_send_ack(const struct sock *sk, struct sk_buff *skb, struct tcp_key key = {}; #ifdef CONFIG_TCP_AO - if (tcp_rsk_used_ao(req)) { + if (static_branch_unlikely(&tcp_ao_needed.key) && + tcp_rsk_used_ao(req)) { const struct in6_addr *addr = &ipv6_hdr(skb)->saddr; const struct tcp_ao_hdr *aoh; int l3index; -- 2.42.0
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