From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 76C6AC00140 for ; Tue, 26 Jul 2022 20:16:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239912AbiGZUQu (ORCPT ); Tue, 26 Jul 2022 16:16:50 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52002 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239864AbiGZUQW (ORCPT ); Tue, 26 Jul 2022 16:16:22 -0400 Received: from mail-wr1-x42b.google.com (mail-wr1-x42b.google.com [IPv6:2a00:1450:4864:20::42b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 147F1326FD for ; Tue, 26 Jul 2022 13:16:14 -0700 (PDT) Received: by mail-wr1-x42b.google.com with SMTP id v17so2669502wrr.10 for ; Tue, 26 Jul 2022 13:16:13 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=arista.com; s=google; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc; bh=pmSO5o3Q44tqKwKFfKNMm0Ze8ef3CVpVV9CI9yXzviE=; b=D5lUTewwVLHHGjzMcNus5GsYhY5VOyJ5EbsBDumqrRq9zpSv8LL+NILNY+idc7V+jy gwssJlDW4770QDmmsH1d8Z2O7J/OOre7FLr4zdjpP6erd/N5/yx5S7DUdz/51yqjxP1F XkQpdIlAPcuuU9EK2Hp55iUVvyctYxw5oBCKEMSQJ7N5BNayUJNb8F5yjlmA8z28kUVP A/AzsOtOML497PIrxw9l3CfdJCNw9/gT3tP0R6Td5iUkT08C2NtmMEKETjiSeQZku+3s IoRefq1rlqZP+SVAhReLcNqCIZfD07wbzR0r9SkPpyEzb0AaR/oVqFPa8A4oqfVyQGOU pNtg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc; bh=pmSO5o3Q44tqKwKFfKNMm0Ze8ef3CVpVV9CI9yXzviE=; b=weeZ+ZhaMTRrbQ/hfRiQdF4CPInQxHdOqTvSxw1vsavhwqmEytqomt9WYZn6fnyym5 eHWwh35B5N+pEHZ+Ziu4oj850bG2CVYHhjx6QbRQyvopinLfg84kYTRM0y4s76+eFrxN vg5nktEHCUyas2de9D4SP45usKBHfp5sc/Lza3Iic58SowQyhm7fO3A7gLoZwJJfi7rP 2RDmbmtyLIq6zThnE1jxvOVto3nsuR/fqgLUSyKRzA1djbALrStBBI/p/V5anrXa88Vz T7PtZWhtDq/Gb54CavFh9OxKxdi9fuIZleNVLsCRgfCJ7oA0pwRTNQA0JtaRwRAVm6rk WCsw== X-Gm-Message-State: AJIora8LSOkhYYRlw7k6z7Ghp0/XMvjeCNHqEVjZmGzy4pn3W4esPN2P 7xGb0CLyyOIM6JLyt2phbICyuA== X-Google-Smtp-Source: AGRyM1uB79Y9Ri2seTNWcO7Gq0vlx1PC/AF/5zeWVVl++TFNfM6zhF2Jc/Q/fwlASGpGWU8eiPG99Q== X-Received: by 2002:a05:6000:986:b0:21e:939b:a71 with SMTP id by6-20020a056000098600b0021e939b0a71mr5780694wrb.256.1658866572371; Tue, 26 Jul 2022 13:16:12 -0700 (PDT) Received: from Mindolluin.ire.aristanetworks.com ([217.173.96.166]) by smtp.gmail.com with ESMTPSA id m6-20020a05600c3b0600b003a320e6f011sm28073wms.1.2022.07.26.13.16.11 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 26 Jul 2022 13:16:11 -0700 (PDT) From: Dmitry Safonov To: linux-kernel@vger.kernel.org Cc: Dmitry Safonov <0x7f454c46@gmail.com>, Dmitry Safonov , Andy Lutomirski , Ard Biesheuvel , David Ahern , "David S. Miller" , Eric Biggers , Eric Dumazet , Francesco Ruggeri , Herbert Xu , Hideaki YOSHIFUJI , Jakub Kicinski , Leonard Crestez , Paolo Abeni , Salam Noureddine , netdev@vger.kernel.org, linux-crypto@vger.kernel.org Subject: [PATCH 4/6] net/tcp: Disable TCP-MD5 static key on tcp_md5sig_info destruction Date: Tue, 26 Jul 2022 21:15:58 +0100 Message-Id: <20220726201600.1715505-5-dima@arista.com> X-Mailer: git-send-email 2.36.1 In-Reply-To: <20220726201600.1715505-1-dima@arista.com> References: <20220726201600.1715505-1-dima@arista.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-crypto@vger.kernel.org To do that, separate two scenarios: - where it's the first MD5 key on the system, which means that enabling of the static key may need to sleep; - copying of an existing key from a listening socket to the request socket upon receiving a signed TCP segment, where static key was already enabled (when the key was added to the listening socket). Now the life-time of the static branch for TCP-MD5 is until: - last tcp_md5sig_info is destroyed - last socket in time-wait state with MD5 key is closed. Which means that after all sockets with TCP-MD5 keys are gone, the system gets back the performance of disabled md5-key static branch. Signed-off-by: Dmitry Safonov --- include/net/tcp.h | 10 ++++++--- net/ipv4/tcp.c | 5 +---- net/ipv4/tcp_ipv4.c | 45 +++++++++++++++++++++++++++++++--------- net/ipv4/tcp_minisocks.c | 9 +++++--- net/ipv4/tcp_output.c | 4 ++-- net/ipv6/tcp_ipv6.c | 10 ++++----- 6 files changed, 55 insertions(+), 28 deletions(-) diff --git a/include/net/tcp.h b/include/net/tcp.h index f366626cbbba..aa735f963723 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -1663,7 +1663,11 @@ int tcp_v4_md5_hash_skb(char *md5_hash, const struct tcp_md5sig_key *key, const struct sock *sk, const struct sk_buff *skb); int tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr, int family, u8 prefixlen, int l3index, u8 flags, - const u8 *newkey, u8 newkeylen, gfp_t gfp); + const u8 *newkey, u8 newkeylen); +int tcp_md5_key_copy(struct sock *sk, const union tcp_md5_addr *addr, + int family, u8 prefixlen, int l3index, + struct tcp_md5sig_key *key); + int tcp_md5_do_del(struct sock *sk, const union tcp_md5_addr *addr, int family, u8 prefixlen, int l3index, u8 flags); struct tcp_md5sig_key *tcp_v4_md5_lookup(const struct sock *sk, @@ -1671,7 +1675,7 @@ struct tcp_md5sig_key *tcp_v4_md5_lookup(const struct sock *sk, #ifdef CONFIG_TCP_MD5SIG #include -extern struct static_key_false tcp_md5_needed; +extern struct static_key_false_deferred tcp_md5_needed; struct tcp_md5sig_key *__tcp_md5_do_lookup(const struct sock *sk, int l3index, const union tcp_md5_addr *addr, int family); @@ -1679,7 +1683,7 @@ static inline struct tcp_md5sig_key * tcp_md5_do_lookup(const struct sock *sk, int l3index, const union tcp_md5_addr *addr, int family) { - if (!static_branch_unlikely(&tcp_md5_needed)) + if (!static_branch_unlikely(&tcp_md5_needed.key)) return NULL; return __tcp_md5_do_lookup(sk, l3index, addr, family); } diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 635c6782cdbb..300056008e90 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -4404,11 +4404,8 @@ bool tcp_alloc_md5sig_pool(void) if (unlikely(!tcp_md5sig_pool_populated)) { mutex_lock(&tcp_md5sig_mutex); - if (!tcp_md5sig_pool_populated) { + if (!tcp_md5sig_pool_populated) __tcp_alloc_md5sig_pool(); - if (tcp_md5sig_pool_populated) - static_branch_inc(&tcp_md5_needed); - } mutex_unlock(&tcp_md5sig_mutex); } diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index 55e4092209a5..5b0caaea5029 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -1044,7 +1044,7 @@ static void tcp_v4_reqsk_destructor(struct request_sock *req) * We need to maintain these in the sk structure. */ -DEFINE_STATIC_KEY_FALSE(tcp_md5_needed); +DEFINE_STATIC_KEY_DEFERRED_FALSE(tcp_md5_needed, HZ); EXPORT_SYMBOL(tcp_md5_needed); static bool better_md5_match(struct tcp_md5sig_key *old, struct tcp_md5sig_key *new) @@ -1171,9 +1171,9 @@ static int tcp_md5sig_info_add(struct sock *sk, gfp_t gfp) } /* This can be called on a newly created socket, from other files */ -int tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr, - int family, u8 prefixlen, int l3index, u8 flags, - const u8 *newkey, u8 newkeylen, gfp_t gfp) +int __tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr, + int family, u8 prefixlen, int l3index, u8 flags, + const u8 *newkey, u8 newkeylen, gfp_t gfp) { /* Add Key to the list */ struct tcp_md5sig_key *key; @@ -1200,9 +1200,6 @@ int tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr, return 0; } - if (tcp_md5sig_info_add(sk, gfp)) - return -ENOMEM; - md5sig = rcu_dereference_protected(tp->md5sig_info, lockdep_sock_is_held(sk)); @@ -1226,8 +1223,36 @@ int tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr, hlist_add_head_rcu(&key->node, &md5sig->head); return 0; } + +int tcp_md5_do_add(struct sock *sk, const union tcp_md5_addr *addr, + int family, u8 prefixlen, int l3index, u8 flags, + const u8 *newkey, u8 newkeylen) +{ + if (tcp_md5sig_info_add(sk, GFP_KERNEL)) + return -ENOMEM; + + static_branch_inc(&tcp_md5_needed.key); + + return __tcp_md5_do_add(sk, addr, family, prefixlen, l3index, flags, + newkey, newkeylen, GFP_KERNEL); +} EXPORT_SYMBOL(tcp_md5_do_add); +int tcp_md5_key_copy(struct sock *sk, const union tcp_md5_addr *addr, + int family, u8 prefixlen, int l3index, + struct tcp_md5sig_key *key) +{ + if (tcp_md5sig_info_add(sk, sk_gfp_mask(sk, GFP_ATOMIC))) + return -ENOMEM; + + atomic_inc(&tcp_md5_needed.key.key.enabled); + + return __tcp_md5_do_add(sk, addr, family, prefixlen, l3index, + key->flags, key->key, key->keylen, + sk_gfp_mask(sk, GFP_ATOMIC)); +} +EXPORT_SYMBOL(tcp_md5_key_copy); + int tcp_md5_do_del(struct sock *sk, const union tcp_md5_addr *addr, int family, u8 prefixlen, int l3index, u8 flags) { @@ -1314,7 +1339,7 @@ static int tcp_v4_parse_md5_keys(struct sock *sk, int optname, return -EINVAL; return tcp_md5_do_add(sk, addr, AF_INET, prefixlen, l3index, flags, - cmd.tcpm_key, cmd.tcpm_keylen, GFP_KERNEL); + cmd.tcpm_key, cmd.tcpm_keylen); } static int tcp_v4_md5_hash_headers(struct tcp_md5sig_pool *hp, @@ -1571,8 +1596,7 @@ struct sock *tcp_v4_syn_recv_sock(const struct sock *sk, struct sk_buff *skb, * memory, then we end up not copying the key * across. Shucks. */ - tcp_md5_do_add(newsk, addr, AF_INET, 32, l3index, key->flags, - key->key, key->keylen, GFP_ATOMIC); + tcp_md5_key_copy(newsk, addr, AF_INET, 32, l3index, key); sk_gso_disable(newsk); } #endif @@ -2260,6 +2284,7 @@ void tcp_v4_destroy_sock(struct sock *sk) tcp_clear_md5_list(sk); kfree_rcu(rcu_dereference_protected(tp->md5sig_info, 1), rcu); tp->md5sig_info = NULL; + static_branch_slow_dec_deferred(&tcp_md5_needed); } #endif diff --git a/net/ipv4/tcp_minisocks.c b/net/ipv4/tcp_minisocks.c index cb95d88497ae..5d475a45a478 100644 --- a/net/ipv4/tcp_minisocks.c +++ b/net/ipv4/tcp_minisocks.c @@ -291,13 +291,14 @@ void tcp_time_wait(struct sock *sk, int state, int timeo) */ do { tcptw->tw_md5_key = NULL; - if (static_branch_unlikely(&tcp_md5_needed)) { + if (static_branch_unlikely(&tcp_md5_needed.key)) { struct tcp_md5sig_key *key; key = tp->af_specific->md5_lookup(sk, sk); if (key) { tcptw->tw_md5_key = kmemdup(key, sizeof(*key), GFP_ATOMIC); BUG_ON(tcptw->tw_md5_key && !tcp_alloc_md5sig_pool()); + atomic_inc(&tcp_md5_needed.key.key.enabled); } } } while (0); @@ -337,11 +338,13 @@ EXPORT_SYMBOL(tcp_time_wait); void tcp_twsk_destructor(struct sock *sk) { #ifdef CONFIG_TCP_MD5SIG - if (static_branch_unlikely(&tcp_md5_needed)) { + if (static_branch_unlikely(&tcp_md5_needed.key)) { struct tcp_timewait_sock *twsk = tcp_twsk(sk); - if (twsk->tw_md5_key) + if (twsk->tw_md5_key) { kfree_rcu(twsk->tw_md5_key, rcu); + static_branch_slow_dec_deferred(&tcp_md5_needed); + } } #endif } diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index 78b654ff421b..9e12845a8758 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -766,7 +766,7 @@ static unsigned int tcp_syn_options(struct sock *sk, struct sk_buff *skb, *md5 = NULL; #ifdef CONFIG_TCP_MD5SIG - if (static_branch_unlikely(&tcp_md5_needed) && + if (static_branch_unlikely(&tcp_md5_needed.key) && rcu_access_pointer(tp->md5sig_info)) { *md5 = tp->af_specific->md5_lookup(sk, sk); if (*md5) { @@ -922,7 +922,7 @@ static unsigned int tcp_established_options(struct sock *sk, struct sk_buff *skb *md5 = NULL; #ifdef CONFIG_TCP_MD5SIG - if (static_branch_unlikely(&tcp_md5_needed) && + if (static_branch_unlikely(&tcp_md5_needed.key) && rcu_access_pointer(tp->md5sig_info)) { *md5 = tp->af_specific->md5_lookup(sk, sk); if (*md5) { diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c index e54eee80ce5f..cb891a71db0d 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -658,12 +658,11 @@ static int tcp_v6_parse_md5_keys(struct sock *sk, int optname, if (ipv6_addr_v4mapped(&sin6->sin6_addr)) return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin6->sin6_addr.s6_addr32[3], AF_INET, prefixlen, l3index, flags, - cmd.tcpm_key, cmd.tcpm_keylen, - GFP_KERNEL); + cmd.tcpm_key, cmd.tcpm_keylen); return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin6->sin6_addr, AF_INET6, prefixlen, l3index, flags, - cmd.tcpm_key, cmd.tcpm_keylen, GFP_KERNEL); + cmd.tcpm_key, cmd.tcpm_keylen); } static int tcp_v6_md5_hash_headers(struct tcp_md5sig_pool *hp, @@ -1359,9 +1358,8 @@ static struct sock *tcp_v6_syn_recv_sock(const struct sock *sk, struct sk_buff * * memory, then we end up not copying the key * across. Shucks. */ - tcp_md5_do_add(newsk, (union tcp_md5_addr *)&newsk->sk_v6_daddr, - AF_INET6, 128, l3index, key->flags, key->key, key->keylen, - sk_gfp_mask(sk, GFP_ATOMIC)); + tcp_md5_key_copy(newsk, (union tcp_md5_addr *)&newsk->sk_v6_daddr, + AF_INET6, 128, l3index, key); } #endif -- 2.36.1