From patchwork Tue Nov 15 21:19:03 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dmitry Safonov X-Patchwork-Id: 13044184 X-Patchwork-Delegate: kuba@kernel.org 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 11558C433FE for ; Tue, 15 Nov 2022 21:20:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231263AbiKOVUG (ORCPT ); Tue, 15 Nov 2022 16:20:06 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45250 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229642AbiKOVTy (ORCPT ); Tue, 15 Nov 2022 16:19:54 -0500 Received: from mail-wr1-x432.google.com (mail-wr1-x432.google.com [IPv6:2a00:1450:4864:20::432]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3166622BE9 for ; Tue, 15 Nov 2022 13:19:46 -0800 (PST) Received: by mail-wr1-x432.google.com with SMTP id y16so26538805wrt.12 for ; Tue, 15 Nov 2022 13:19:46 -0800 (PST) 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:subject:date :message-id:reply-to; bh=8ytIn/f+EUf0Gut52ap1rHBQbXWl5H51uEoiN5mmkBA=; b=Hjb3rwnvy5J/tPYCYlfzXFAHL78C/DTsPOojbblL2x0Xffy+7PYL5Rb7blti/r1KrR plYEZCrFvBqOEfp6RMVTiHGA6R/fxD5Yx9Zyld2znG2I9WXnFDcSEupBY34xsc0wpXFa fz2mRLdr5FUSk0PfX+/uS1MazWafd9vv2TuTMHnNAIofjusC2OtImls3v7Q8Ei/Qcpgh BtLnyudfIzkKv0BivTAfoUVHPPyNesVTvawOKVN0m2CgtcoTGghRSHQMzF3m329cS5d2 UaFH7elxAcJ4JaRA6kGhbO+8U0/08DZwNHGOw3TAwiLtJ09VusNCu2hOOUy8bXtZchQH /rZw== 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 :subject:date:message-id:reply-to; bh=8ytIn/f+EUf0Gut52ap1rHBQbXWl5H51uEoiN5mmkBA=; b=OIhAOaAZuD5Rg5GYf842V7gNBgPsmJAKsfoeYzVJ7hduuMlCDPuZn6cQ+NhNi7ocSY 7VxzMwHhdQI+IXwUYhj3s+aZkPaBIM2eCogYGHJpWbnUdu9MfU8AohzetaXF5k0QSvnL az1XtKCSoHW0yrd9ge+QQtK4Vit1fNIlRyGF/7DSmnD46qR1BYb4lujE9QcWVqQnnkxg 6RXyN3Um1iEGF6NBWefuzWOjlE9M3uA6rErtKvMWf1zdAxEuP3ugNoMsdQI/QYp4aXEl Ui5Z6+i37ekE/xXK0gMFpbYaPSl59fRnBaXwersehnMm8TLLniiRILJbAbzh/4T71GZp 9CUw== X-Gm-Message-State: ANoB5pmuJqvMgu6CO8dDTtdRROwEMc6is7aERn52YBdm98KhuMq3NAip YQlKWVefTXmdnkNVuXaf6ySuQA== X-Google-Smtp-Source: AA0mqf5/1fc/ay9S0qpZ54QCPXaSLIzjDWNemj6uxkgk8CUEeEG5LDZOPSSj+ws62hfg6uC4hghirg== X-Received: by 2002:adf:f34b:0:b0:240:e14:cfa8 with SMTP id e11-20020adff34b000000b002400e14cfa8mr11819668wrp.63.1668547157217; Tue, 15 Nov 2022 13:19:17 -0800 (PST) Received: from Mindolluin.ire.aristanetworks.com ([217.173.96.166]) by smtp.gmail.com with ESMTPSA id n41-20020a05600c502900b003c65c9a36dfsm17201487wmr.48.2022.11.15.13.19.15 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 15 Nov 2022 13:19:16 -0800 (PST) From: Dmitry Safonov To: linux-kernel@vger.kernel.org, David Ahern , Eric Dumazet , Peter Zijlstra Cc: Dmitry Safonov , Ard Biesheuvel , Bob Gilligan , "David S. Miller" , Dmitry Safonov <0x7f454c46@gmail.com>, Francesco Ruggeri , Hideaki YOSHIFUJI , Jakub Kicinski , Jason Baron , Josh Poimboeuf , Paolo Abeni , Salam Noureddine , Steven Rostedt , netdev@vger.kernel.org Subject: [PATCH v4 3/5] net/tcp: Disable TCP-MD5 static key on tcp_md5sig_info destruction Date: Tue, 15 Nov 2022 21:19:03 +0000 Message-Id: <20221115211905.1685426-4-dima@arista.com> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221115211905.1685426-1-dima@arista.com> References: <20221115211905.1685426-1-dima@arista.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org 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. While at here, provide static_key_fast_inc() helper that does ref counter increment in atomic fashion (without grabbing cpus_read_lock() on CONFIG_JUMP_LABEL=y). This is needed to add a new user for a static_key when the caller controls the lifetime of another user. Signed-off-by: Dmitry Safonov Acked-by: Jakub Kicinski --- include/linux/jump_label.h | 4 ++- include/net/tcp.h | 10 ++++-- kernel/jump_label.c | 3 +- net/ipv4/tcp.c | 5 +-- net/ipv4/tcp_ipv4.c | 69 +++++++++++++++++++++++++++++++------- net/ipv4/tcp_minisocks.c | 16 ++++++--- net/ipv4/tcp_output.c | 4 +-- net/ipv6/tcp_ipv6.c | 10 +++--- 8 files changed, 87 insertions(+), 34 deletions(-) diff --git a/include/linux/jump_label.h b/include/linux/jump_label.h index c0a02d4c2ea2..f3fc5081cae6 100644 --- a/include/linux/jump_label.h +++ b/include/linux/jump_label.h @@ -225,6 +225,7 @@ extern bool arch_jump_label_transform_queue(struct jump_entry *entry, extern void arch_jump_label_transform_apply(void); extern int jump_label_text_reserved(void *start, void *end); extern bool static_key_slow_inc(struct static_key *key); +extern bool static_key_fast_inc_not_negative(struct static_key *key); extern void static_key_slow_dec(struct static_key *key); extern bool static_key_slow_inc_cpuslocked(struct static_key *key); extern void static_key_slow_dec_cpuslocked(struct static_key *key); @@ -278,7 +279,7 @@ static __always_inline bool static_key_true(struct static_key *key) return false; } -static inline bool static_key_slow_inc(struct static_key *key) +static inline bool static_key_fast_inc_not_negative(struct static_key *key) { int v; @@ -294,6 +295,7 @@ static inline bool static_key_slow_inc(struct static_key *key) } while (!likely(atomic_try_cmpxchg(&key->enabled, &v, v + 1))); return true; } +#define static_key_slow_inc(key) static_key_fast_inc_not_negative(key) static inline void static_key_slow_dec(struct static_key *key) { diff --git a/include/net/tcp.h b/include/net/tcp.h index 14d45661a84d..a0cdf013782a 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -1675,7 +1675,11 @@ 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, @@ -1683,7 +1687,7 @@ 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); @@ -1691,7 +1695,7 @@ 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/kernel/jump_label.c b/kernel/jump_label.c index 677a6674c130..32c785f5d2b1 100644 --- a/kernel/jump_label.c +++ b/kernel/jump_label.c @@ -123,7 +123,7 @@ EXPORT_SYMBOL_GPL(static_key_count); * * Returns true if the increment was done. */ -static bool static_key_fast_inc_not_negative(struct static_key *key) +bool static_key_fast_inc_not_negative(struct static_key *key) { int v; @@ -142,6 +142,7 @@ static bool static_key_fast_inc_not_negative(struct static_key *key) return true; } +EXPORT_SYMBOL_GPL(static_key_fast_inc_not_negative); bool static_key_slow_inc_cpuslocked(struct static_key *key) { diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 54836a6b81d6..07a73c9b49da 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -4460,11 +4460,8 @@ bool tcp_alloc_md5sig_pool(void) if (unlikely(!READ_ONCE(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 fae80b1a1796..4bdb6e1ecaf3 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -1064,7 +1064,7 @@ 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) @@ -1177,9 +1177,6 @@ static int tcp_md5sig_info_add(struct sock *sk, gfp_t gfp) struct tcp_sock *tp = tcp_sk(sk); struct tcp_md5sig_info *md5sig; - if (rcu_dereference_protected(tp->md5sig_info, lockdep_sock_is_held(sk))) - return 0; - md5sig = kmalloc(sizeof(*md5sig), gfp); if (!md5sig) return -ENOMEM; @@ -1191,9 +1188,9 @@ 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) +static 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; @@ -1220,9 +1217,6 @@ 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)); @@ -1246,8 +1240,57 @@ 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) +{ + struct tcp_sock *tp = tcp_sk(sk); + + if (!rcu_dereference_protected(tp->md5sig_info, lockdep_sock_is_held(sk))) { + if (tcp_md5sig_info_add(sk, GFP_KERNEL)) + return -ENOMEM; + + if (!static_branch_inc(&tcp_md5_needed.key)) { + struct tcp_md5sig_info *md5sig = tp->md5sig_info; + + rcu_assign_pointer(tp->md5sig_info, NULL); + kfree_rcu(md5sig); + return -EUSERS; + } + } + + 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) +{ + struct tcp_sock *tp = tcp_sk(sk); + + if (!rcu_dereference_protected(tp->md5sig_info, lockdep_sock_is_held(sk))) { + if (tcp_md5sig_info_add(sk, sk_gfp_mask(sk, GFP_ATOMIC))) + return -ENOMEM; + + if (!static_key_fast_inc_not_negative(&tcp_md5_needed.key.key)) { + struct tcp_md5sig_info *md5sig = tp->md5sig_info; + + net_warn_ratelimited("Too many TCP-MD5 keys in the system\n"); + rcu_assign_pointer(tp->md5sig_info, NULL); + kfree_rcu(md5sig); + return -EUSERS; + } + } + + 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) { @@ -1334,7 +1377,7 @@ 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, @@ -1591,8 +1634,7 @@ 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 @@ -2284,6 +2326,7 @@ 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 c375f603a16c..50f91c10eb7b 100644 --- a/net/ipv4/tcp_minisocks.c +++ b/net/ipv4/tcp_minisocks.c @@ -291,13 +291,19 @@ 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()); + if (!tcptw->tw_md5_key) + break; + BUG_ON(!tcp_alloc_md5sig_pool()); + if (!static_key_fast_inc_not_negative(&tcp_md5_needed.key.key)) { + kfree(tcptw->tw_md5_key); + tcptw->tw_md5_key = NULL; + } } } } while (0); @@ -337,11 +343,13 @@ 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 c69f4d966024..86e71c8c76bc 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 2a3f9296df1e..3e3bdc120fc8 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -677,12 +677,11 @@ 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, @@ -1382,9 +1381,8 @@ 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