From patchwork Tue May 9 22:16:04 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dmitry Safonov X-Patchwork-Id: 13236196 X-Patchwork-Delegate: kuba@kernel.org 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 92FB918C05 for ; Tue, 9 May 2023 22:16:20 +0000 (UTC) Received: from mail-wm1-x336.google.com (mail-wm1-x336.google.com [IPv6:2a00:1450:4864:20::336]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2E6B23A8B for ; Tue, 9 May 2023 15:16:18 -0700 (PDT) Received: by mail-wm1-x336.google.com with SMTP id 5b1f17b1804b1-3f475366514so729205e9.2 for ; Tue, 09 May 2023 15:16:18 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=arista.com; s=google; t=1683670576; x=1686262576; 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=Y6EGYjnQ/WyZ5lGG/G0UzhGu7aE+rdmJ2jNh/CB1dks=; b=NIA7icVyTxq2prfx2oVx3NhEvGTxl+OLH+p4cw1f0R+gTgse1UwmNXScSEQ6kpw5X6 /arhlTSLX9QD9kWvlhL8dUXgpMGI1bLd7P5izg1zAl8MbVzb0N3qcfMCbk+f2LBiO9TN bboQ+Pu0dhB//juC0VYaz5jA6LowIYlo6p50FcrMpQZNkmT6H/VzsaILEPb33xT47RtA /FbYxbnZzJtdBLs0vDuZzIqwGt7zVEgI/PgdXKqLIE3I/LzSUS3N3K3Oj/fpiZu/LNaZ cpiygz5BU4fJR9S75nrsvsE3KMwoHr1rRDxvpVhQ8v8QYR2v969QoL1jfTQ7UflEbbVy BH5g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1683670576; x=1686262576; 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=Y6EGYjnQ/WyZ5lGG/G0UzhGu7aE+rdmJ2jNh/CB1dks=; b=X2LRnW1m9aV/D4o3aeSEV9vUev9ODAH58Kqj4wZwg2SYkD0Ey89aWT2TH4WuAUzb/y qMidbVGzBfyRMgCCHQt8ezk7Xqg03oUoOmQ4QvxfK3Wxievp4ATnlAmFo91alLcU8aZj x9mHwX7LWI4lXKNyl4mkNcvoRxH/i6er2oXQai47YJP0BanmHUsdX2OjN+RvQW9Nesi5 kioyZy90ONCmOtPZjXC8l1oOdLH+JXVilferwCkndZQddBvupRf78LHRPkZ2JZ+406p5 cepzx6yu44ZYXasVSlOq6+b1SO3D03LCdDboHgn+Svp6wZb1h8RRsVzzend+Hte4BCuP JDrQ== X-Gm-Message-State: AC+VfDxx8p6kv3bBNGaTo4lFXEGf/uGnjyg+NPPpCXhdcr8NFSUrRh2b jUakoStbyFKJ+3PfGlFNGXImuw== X-Google-Smtp-Source: ACHHUZ6wgvotrUb/tm0TOg0te2P4XxsvMPXWrxHm+qcAywC9h/wd9u01Ef+pBiYFL4pQQDhwCkmTKQ== X-Received: by 2002:a1c:7c10:0:b0:3f4:253b:92b3 with SMTP id x16-20020a1c7c10000000b003f4253b92b3mr5795825wmc.18.1683670576558; Tue, 09 May 2023 15:16:16 -0700 (PDT) Received: from Mindolluin.ire.aristanetworks.com ([217.173.96.166]) by smtp.gmail.com with ESMTPSA id t25-20020a7bc3d9000000b003f42d3111b8sm2052888wmj.30.2023.05.09.15.16.15 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 09 May 2023 15:16:16 -0700 (PDT) From: Dmitry Safonov To: linux-kernel@vger.kernel.org, David Ahern , Eric Dumazet , Paolo Abeni , Jakub Kicinski , "David S. Miller" Cc: Dmitry Safonov , Dmitry Safonov <0x7f454c46@gmail.com>, Hideaki YOSHIFUJI , Leonard Crestez , Salam Noureddine , netdev@vger.kernel.org Subject: [PATCH 1/5] net/tcp: Separate TCP-MD5 signing from tcp_v{4,6}_send_reset() Date: Tue, 9 May 2023 23:16:04 +0100 Message-Id: <20230509221608.2569333-2-dima@arista.com> X-Mailer: git-send-email 2.40.0 In-Reply-To: <20230509221608.2569333-1-dima@arista.com> References: <20230509221608.2569333-1-dima@arista.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE, SPF_HELO_NONE,SPF_NONE,T_SCC_BODY_TEXT_LINE,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net X-Patchwork-Delegate: kuba@kernel.org Separate TCP-MD5 part from the generic TCP code, cleaning it up from MD5-related ifdeffery (this is most noticeable on ipv4 part). Mostly, it is refactoring, but with a small bonus: now RST sending functions can nicely get tcp_md5_needed static key check, making them faster on systems without TCP-MD5 keys. Signed-off-by: Dmitry Safonov --- net/ipv4/tcp_ipv4.c | 177 +++++++++++++++++++++++--------------------- net/ipv6/tcp_ipv6.c | 106 ++++++++++++++------------ 2 files changed, 152 insertions(+), 131 deletions(-) diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index 39bda2b1066e..b1056a4af60f 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -655,6 +655,97 @@ void tcp_v4_send_check(struct sock *sk, struct sk_buff *skb) } EXPORT_SYMBOL(tcp_v4_send_check); +#define REPLY_OPTIONS_LEN (MAX_TCP_OPTION_SPACE / sizeof(__be32)) + +static bool tcp_v4_md5_sign_reset(struct net *net, const struct sock *sk, + struct sk_buff *skb, struct ip_reply_arg *arg, + struct tcphdr *reply, + __be32 reply_options[REPLY_OPTIONS_LEN]) +{ +#ifdef CONFIG_TCP_MD5SIG + const struct tcphdr *th = tcp_hdr(skb); + struct tcp_md5sig_key *key = NULL; + const __u8 *hash_location = NULL; + unsigned char newhash[16]; + struct sock *sk1 = NULL; + int genhash; + + hash_location = tcp_parse_md5sig_option(th); + /* Fastpath: no keys in system, don't send RST iff segment is signed */ + if (!static_branch_unlikely(&tcp_md5_needed.key)) + return !!hash_location; + + rcu_read_lock(); + if (sk && sk_fullsock(sk)) { + const union tcp_md5_addr *addr; + int l3index; + + /* sdif set, means packet ingressed via a device + * in an L3 domain and inet_iif is set to it. + */ + l3index = tcp_v4_sdif(skb) ? inet_iif(skb) : 0; + addr = (union tcp_md5_addr *)&ip_hdr(skb)->saddr; + key = tcp_md5_do_lookup(sk, l3index, addr, AF_INET); + } else if (hash_location) { + const union tcp_md5_addr *addr; + int sdif = tcp_v4_sdif(skb); + int dif = inet_iif(skb); + int l3index; + + /* + * active side is lost. Try to find listening socket through + * source port, and then find md5 key through listening socket. + * we are not loose security here: + * Incoming packet is checked with md5 hash with finding key, + * no RST generated if md5 hash doesn't match. + */ + sk1 = __inet_lookup_listener(net, net->ipv4.tcp_death_row.hashinfo, + NULL, 0, ip_hdr(skb)->saddr, + th->source, ip_hdr(skb)->daddr, + ntohs(th->source), dif, sdif); + /* don't send rst if it can't find key */ + if (!sk1) { + rcu_read_unlock(); + return true; + } + + /* sdif set, means packet ingressed via a device + * in an L3 domain and dif is set to it. + */ + l3index = sdif ? dif : 0; + addr = (union tcp_md5_addr *)&ip_hdr(skb)->saddr; + key = tcp_md5_do_lookup(sk1, l3index, addr, AF_INET); + if (!key) { + rcu_read_unlock(); + return true; + } + + genhash = tcp_v4_md5_hash_skb(newhash, key, NULL, skb); + if (genhash || memcmp(hash_location, newhash, 16) != 0) { + rcu_read_unlock(); + return true; + } + } + + if (key) { + reply_options[0] = htonl((TCPOPT_NOP << 24) | + (TCPOPT_NOP << 16) | + (TCPOPT_MD5SIG << 8) | + TCPOLEN_MD5SIG); + /* Update length and the length the header thinks exists */ + arg->iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED; + reply->doff = arg->iov[0].iov_len / 4; + + tcp_v4_md5_hash_hdr((__u8 *)&reply_options[1], + key, ip_hdr(skb)->saddr, + ip_hdr(skb)->daddr, reply); + } + rcu_read_unlock(); +#endif + + return false; +} + /* * This routine will send an RST to the other tcp. * @@ -668,27 +759,14 @@ EXPORT_SYMBOL(tcp_v4_send_check); * Exception: precedence violation. We do not implement it in any case. */ -#ifdef CONFIG_TCP_MD5SIG -#define OPTION_BYTES TCPOLEN_MD5SIG_ALIGNED -#else -#define OPTION_BYTES sizeof(__be32) -#endif - static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb) { const struct tcphdr *th = tcp_hdr(skb); struct { struct tcphdr th; - __be32 opt[OPTION_BYTES / sizeof(__be32)]; + __be32 opt[REPLY_OPTIONS_LEN]; } rep; struct ip_reply_arg arg; -#ifdef CONFIG_TCP_MD5SIG - struct tcp_md5sig_key *key = NULL; - const __u8 *hash_location = NULL; - unsigned char newhash[16]; - int genhash; - struct sock *sk1 = NULL; -#endif u64 transmit_time = 0; struct sock *ctl_sk; struct net *net; @@ -723,70 +801,8 @@ static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb) arg.iov[0].iov_len = sizeof(rep.th); net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev); -#ifdef CONFIG_TCP_MD5SIG - rcu_read_lock(); - hash_location = tcp_parse_md5sig_option(th); - if (sk && sk_fullsock(sk)) { - const union tcp_md5_addr *addr; - int l3index; - - /* sdif set, means packet ingressed via a device - * in an L3 domain and inet_iif is set to it. - */ - l3index = tcp_v4_sdif(skb) ? inet_iif(skb) : 0; - addr = (union tcp_md5_addr *)&ip_hdr(skb)->saddr; - key = tcp_md5_do_lookup(sk, l3index, addr, AF_INET); - } else if (hash_location) { - const union tcp_md5_addr *addr; - int sdif = tcp_v4_sdif(skb); - int dif = inet_iif(skb); - int l3index; - - /* - * active side is lost. Try to find listening socket through - * source port, and then find md5 key through listening socket. - * we are not loose security here: - * Incoming packet is checked with md5 hash with finding key, - * no RST generated if md5 hash doesn't match. - */ - sk1 = __inet_lookup_listener(net, net->ipv4.tcp_death_row.hashinfo, - NULL, 0, ip_hdr(skb)->saddr, - th->source, ip_hdr(skb)->daddr, - ntohs(th->source), dif, sdif); - /* don't send rst if it can't find key */ - if (!sk1) - goto out; - - /* sdif set, means packet ingressed via a device - * in an L3 domain and dif is set to it. - */ - l3index = sdif ? dif : 0; - addr = (union tcp_md5_addr *)&ip_hdr(skb)->saddr; - key = tcp_md5_do_lookup(sk1, l3index, addr, AF_INET); - if (!key) - goto out; - - - genhash = tcp_v4_md5_hash_skb(newhash, key, NULL, skb); - if (genhash || memcmp(hash_location, newhash, 16) != 0) - goto out; - - } - - if (key) { - rep.opt[0] = htonl((TCPOPT_NOP << 24) | - (TCPOPT_NOP << 16) | - (TCPOPT_MD5SIG << 8) | - TCPOLEN_MD5SIG); - /* Update length and the length the header thinks exists */ - arg.iov[0].iov_len += TCPOLEN_MD5SIG_ALIGNED; - rep.th.doff = arg.iov[0].iov_len / 4; - - tcp_v4_md5_hash_hdr((__u8 *) &rep.opt[1], - key, ip_hdr(skb)->saddr, - ip_hdr(skb)->daddr, &rep.th); - } -#endif + if (tcp_v4_md5_sign_reset(net, sk, skb, &arg, &rep.th, rep.opt)) + return; /* Can't co-exist with TCPMD5, hence check rep.opt[0] */ if (rep.opt[0] == 0) { __be32 mrst = mptcp_reset_option(skb); @@ -842,11 +858,6 @@ static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb) __TCP_INC_STATS(net, TCP_MIB_OUTSEGS); __TCP_INC_STATS(net, TCP_MIB_OUTRSTS); local_bh_enable(); - -#ifdef CONFIG_TCP_MD5SIG -out: - rcu_read_unlock(); -#endif } /* The code following below sending ACKs in SYN-RECV and TIME-WAIT states diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c index 7132eb213a7a..42792bc5b9bf 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -977,18 +977,67 @@ static void tcp_v6_send_response(const struct sock *sk, struct sk_buff *skb, u32 kfree_skb(buff); } +#ifdef CONFIG_TCP_MD5SIG +static int tcp_v6_md5_lookup_reset_key(struct net *net, const struct sock *sk, + struct sk_buff *skb, struct tcp_md5sig_key **key, + const struct tcphdr *th, struct ipv6hdr *ipv6h) +{ + const __u8 *hash_location = NULL; + int genhash, l3index; + + hash_location = tcp_parse_md5sig_option(th); + if (!static_branch_unlikely(&tcp_md5_needed.key)) + return !!hash_location; + + if (sk && sk_fullsock(sk)) { + /* sdif set, means packet ingressed via a device + * in an L3 domain and inet_iif is set to it. + */ + l3index = tcp_v6_sdif(skb) ? tcp_v6_iif_l3_slave(skb) : 0; + *key = tcp_v6_md5_do_lookup(sk, &ipv6h->saddr, l3index); + } else if (hash_location) { + int dif = tcp_v6_iif_l3_slave(skb); + int sdif = tcp_v6_sdif(skb); + unsigned char newhash[16]; + struct sock *sk1; + + /* + * active side is lost. Try to find listening socket through + * source port, and then find md5 key through listening socket. + * we are not loose security here: + * Incoming packet is checked with md5 hash with finding key, + * no RST generated if md5 hash doesn't match. + */ + sk1 = inet6_lookup_listener(net, net->ipv4.tcp_death_row.hashinfo, + NULL, 0, &ipv6h->saddr, th->source, + &ipv6h->daddr, ntohs(th->source), + dif, sdif); + if (!sk1) + return -ENOKEY; + + /* sdif set, means packet ingressed via a device + * in an L3 domain and dif is set to it. + */ + l3index = tcp_v6_sdif(skb) ? dif : 0; + + *key = tcp_v6_md5_do_lookup(sk1, &ipv6h->saddr, l3index); + if (!*key) + return -ENOKEY; + + genhash = tcp_v6_md5_hash_skb(newhash, *key, NULL, skb); + if (genhash || memcmp(hash_location, newhash, 16) != 0) + return -EKEYREJECTED; + } + return 0; +} +#endif + static void tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb) { const struct tcphdr *th = tcp_hdr(skb); struct ipv6hdr *ipv6h = ipv6_hdr(skb); - u32 seq = 0, ack_seq = 0; struct tcp_md5sig_key *key = NULL; -#ifdef CONFIG_TCP_MD5SIG - const __u8 *hash_location = NULL; - unsigned char newhash[16]; - int genhash; - struct sock *sk1 = NULL; -#endif + u32 seq = 0, ack_seq = 0; __be32 label = 0; u32 priority = 0; struct net *net; @@ -1007,47 +1056,8 @@ static void tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb) net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev); #ifdef CONFIG_TCP_MD5SIG rcu_read_lock(); - hash_location = tcp_parse_md5sig_option(th); - if (sk && sk_fullsock(sk)) { - int l3index; - - /* sdif set, means packet ingressed via a device - * in an L3 domain and inet_iif is set to it. - */ - l3index = tcp_v6_sdif(skb) ? tcp_v6_iif_l3_slave(skb) : 0; - key = tcp_v6_md5_do_lookup(sk, &ipv6h->saddr, l3index); - } else if (hash_location) { - int dif = tcp_v6_iif_l3_slave(skb); - int sdif = tcp_v6_sdif(skb); - int l3index; - - /* - * active side is lost. Try to find listening socket through - * source port, and then find md5 key through listening socket. - * we are not loose security here: - * Incoming packet is checked with md5 hash with finding key, - * no RST generated if md5 hash doesn't match. - */ - sk1 = inet6_lookup_listener(net, net->ipv4.tcp_death_row.hashinfo, - NULL, 0, &ipv6h->saddr, th->source, - &ipv6h->daddr, ntohs(th->source), - dif, sdif); - if (!sk1) - goto out; - - /* sdif set, means packet ingressed via a device - * in an L3 domain and dif is set to it. - */ - l3index = tcp_v6_sdif(skb) ? dif : 0; - - key = tcp_v6_md5_do_lookup(sk1, &ipv6h->saddr, l3index); - if (!key) - goto out; - - genhash = tcp_v6_md5_hash_skb(newhash, key, NULL, skb); - if (genhash || memcmp(hash_location, newhash, 16) != 0) - goto out; - } + if (tcp_v6_md5_lookup_reset_key(net, sk, skb, &key, th, ipv6h)) + goto out; #endif if (th->ack) From patchwork Tue May 9 22:16:05 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dmitry Safonov X-Patchwork-Id: 13236197 X-Patchwork-Delegate: kuba@kernel.org 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 A77A01952F for ; Tue, 9 May 2023 22:16:21 +0000 (UTC) Received: from mail-wm1-x32e.google.com (mail-wm1-x32e.google.com [IPv6:2a00:1450:4864:20::32e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 58F113A88 for ; Tue, 9 May 2023 15:16:19 -0700 (PDT) Received: by mail-wm1-x32e.google.com with SMTP id 5b1f17b1804b1-3f41dceb93bso26395845e9.1 for ; Tue, 09 May 2023 15:16:19 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=arista.com; s=google; t=1683670578; x=1686262578; 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=TNaNVg3b0b9p/yqj32LHesflwoL6NjpvZvYZ6iwGQ4U=; b=M7PTN/jPtZaCbndrgKXB5fUCiuP/OVHWsN+jZdRGTMrM92yC/uBuA2QYkvFzTEhkgy a8lC+CIRThgZOMqbBUhknW9IB1HHR7iRUa64Eunab591Iahlk2tzjuEI5L4cDcYj4oA4 2JWmYcEBwsrPQE/8sTHxNUeBh3n618jO2ybsjbQdXiIeKcC5RNHNPK5Gn49bsx0BFGbv nyEdnlNxhDL2arE8+9mn41l+RC+anZPWyzKH8iAsyg/EPbD/YrHzxW8dqMtT+nX0BHYw ZYsQcxIt2tYSetXfh29BtDqXLzGEfSuhvtzL5WhBbV2wgKDUOaa123gVyZBNHGAQUyEf KCwQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1683670578; x=1686262578; 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=TNaNVg3b0b9p/yqj32LHesflwoL6NjpvZvYZ6iwGQ4U=; b=fAt8/R+zFSTIif/4vaK8zUYC9IcKwpybAMvJFcBRX1SlOvLdFQvLaUUnyvcVEqThAB XDTbiFfL3ouMG09LXTDCJ9INS+zlTk7MYA6W2QWcgVkPmN2OdZDIFqOPL25k34qbF/oH LB9Hm7fRUuAHoMq9sdf6H0lXKP/AstDeXSM2Ha8ea9iLz3BQf4CdP9rEx65lHFFiDEZJ xokIW4KUSBOnD/qChun3beofBselMkyPLlR8Sbte2XtQzM+I4qgFLHfxElXfAw7G7Fp6 NE6UvVBV0ezuAiitb+8yRfRbZQEOSB03YltjpiTIXRaTcY1iooP/k7BQFDFzpOaEnZiU 2Jqg== X-Gm-Message-State: AC+VfDzQBDFDJXXre6aGDo6+0ddTThdx8QB5huMhFW6ygd55NmUb40AY 7cYPGGBnPVwKwSObnZSeCPaEJw== X-Google-Smtp-Source: ACHHUZ72PpzNWq8SWA6TsHvvINJ8EjbBBRkPnspE4OoKvfr3prJsNXhmoxE9wTRql5V7Jz8yi5i9hw== X-Received: by 2002:a7b:c8d9:0:b0:3f4:2174:b284 with SMTP id f25-20020a7bc8d9000000b003f42174b284mr6687645wml.28.1683670577699; Tue, 09 May 2023 15:16:17 -0700 (PDT) Received: from Mindolluin.ire.aristanetworks.com ([217.173.96.166]) by smtp.gmail.com with ESMTPSA id t25-20020a7bc3d9000000b003f42d3111b8sm2052888wmj.30.2023.05.09.15.16.16 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 09 May 2023 15:16:17 -0700 (PDT) From: Dmitry Safonov To: linux-kernel@vger.kernel.org, David Ahern , Eric Dumazet , Paolo Abeni , Jakub Kicinski , "David S. Miller" Cc: Dmitry Safonov , Dmitry Safonov <0x7f454c46@gmail.com>, Hideaki YOSHIFUJI , Leonard Crestez , Salam Noureddine , netdev@vger.kernel.org Subject: [PATCH 2/5] net/tcp: Use tcp_v6_md5_hash_skb() instead of .calc_md5_hash() Date: Tue, 9 May 2023 23:16:05 +0100 Message-Id: <20230509221608.2569333-3-dima@arista.com> X-Mailer: git-send-email 2.40.0 In-Reply-To: <20230509221608.2569333-1-dima@arista.com> References: <20230509221608.2569333-1-dima@arista.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE, SPF_HELO_NONE,SPF_NONE,T_SCC_BODY_TEXT_LINE,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net X-Patchwork-Delegate: kuba@kernel.org Using af-specific callback requires the socket to be full (struct tcp_sock). Using tcp_v6_md5_hash_skb() instead, depending on passed family parameter makes it possible to use it for non-full sockets as well (if key-lookup succeeds). Next commit uses tcp_inbound_md5_hash() to verify segments on twsk. This seems quite safe to do, as pre-commit 7bbb765b7349 ("net/tcp: Merge TCP-MD5 inbound callbacks") ip-version-specific functions tcp_v{4,6}_inbound_md5_hash were calling tcp_v4_md5_hash_skb()/tcp_v6_md5_hash_skb(). Signed-off-by: Dmitry Safonov --- include/net/tcp.h | 11 +++++++++++ net/ipv4/tcp.c | 9 +++------ net/ipv6/tcp_ipv6.c | 6 ++---- 3 files changed, 16 insertions(+), 10 deletions(-) diff --git a/include/net/tcp.h b/include/net/tcp.h index 04a31643cda3..e127fc685ca6 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -1676,6 +1676,17 @@ struct tcp_md5sig_pool { /* - functions */ int tcp_v4_md5_hash_skb(char *md5_hash, const struct tcp_md5sig_key *key, const struct sock *sk, const struct sk_buff *skb); +#if IS_ENABLED(CONFIG_IPV6) +int tcp_v6_md5_hash_skb(char *md5_hash, const struct tcp_md5sig_key *key, + const struct sock *sk, const struct sk_buff *skb); +#else +static inline int tcp_v6_md5_hash_skb(char *md5_hash, + const struct tcp_md5sig_key *key, + const struct sock *sk, const struct sk_buff *skb) +{ + return -EPROTONOSUPPORT; +} +#endif 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); diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 20db115c38c4..c1897a039ff5 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -4570,7 +4570,6 @@ tcp_inbound_md5_hash(const struct sock *sk, const struct sk_buff *skb, const __u8 *hash_location = NULL; struct tcp_md5sig_key *hash_expected; const struct tcphdr *th = tcp_hdr(skb); - const struct tcp_sock *tp = tcp_sk(sk); int genhash, l3index; u8 newhash[16]; @@ -4601,13 +4600,11 @@ tcp_inbound_md5_hash(const struct sock *sk, const struct sk_buff *skb, * IPv4-mapped case. */ if (family == AF_INET) - genhash = tcp_v4_md5_hash_skb(newhash, - hash_expected, + genhash = tcp_v4_md5_hash_skb(newhash, hash_expected, NULL, skb); else - genhash = tp->af_specific->calc_md5_hash(newhash, - hash_expected, - NULL, skb); + genhash = tcp_v6_md5_hash_skb(newhash, hash_expected, + NULL, skb); if (genhash || memcmp(hash_location, newhash, 16) != 0) { NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5FAILURE); diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c index 42792bc5b9bf..574398a89970 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -732,10 +732,8 @@ static int tcp_v6_md5_hash_hdr(char *md5_hash, const struct tcp_md5sig_key *key, return 1; } -static int tcp_v6_md5_hash_skb(char *md5_hash, - const struct tcp_md5sig_key *key, - const struct sock *sk, - const struct sk_buff *skb) +int tcp_v6_md5_hash_skb(char *md5_hash, const struct tcp_md5sig_key *key, + const struct sock *sk, const struct sk_buff *skb) { const struct in6_addr *saddr, *daddr; struct tcp_md5sig_pool *hp; From patchwork Tue May 9 22:16:06 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dmitry Safonov X-Patchwork-Id: 13236198 X-Patchwork-Delegate: kuba@kernel.org 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 39CDB19E43 for ; Tue, 9 May 2023 22:16:22 +0000 (UTC) Received: from mail-wm1-x330.google.com (mail-wm1-x330.google.com [IPv6:2a00:1450:4864:20::330]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 511093A96 for ; 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Tue, 09 May 2023 15:16:18 -0700 (PDT) From: Dmitry Safonov To: linux-kernel@vger.kernel.org, David Ahern , Eric Dumazet , Paolo Abeni , Jakub Kicinski , "David S. Miller" Cc: Dmitry Safonov , Dmitry Safonov <0x7f454c46@gmail.com>, Hideaki YOSHIFUJI , Leonard Crestez , Salam Noureddine , netdev@vger.kernel.org Subject: [RFC 3/5] net/tcp-md5: Verify inbound segments on twsk Date: Tue, 9 May 2023 23:16:06 +0100 Message-Id: <20230509221608.2569333-4-dima@arista.com> X-Mailer: git-send-email 2.40.0 In-Reply-To: <20230509221608.2569333-1-dima@arista.com> References: <20230509221608.2569333-1-dima@arista.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE, SPF_HELO_NONE,SPF_NONE,T_SCC_BODY_TEXT_LINE,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net X-Patchwork-Delegate: kuba@kernel.org X-Patchwork-State: RFC It seems rare for BGP to have twsk socket and quite unlikely on server side, in addition I don't see any major concern of destroying twsk early by unsigned segments. But on the other hand, it seems better not to change TCP state by unsigned inbound segments and fixing this seems not hard. So, lets avoid replying or doing any TCP state changes as long as the segments weren't verified. Signed-off-by: Dmitry Safonov --- include/net/tcp.h | 7 ++++--- net/ipv4/tcp_ipv4.c | 9 +++++++-- net/ipv6/tcp_ipv6.c | 10 ++++++++-- 3 files changed, 19 insertions(+), 7 deletions(-) diff --git a/include/net/tcp.h b/include/net/tcp.h index e127fc685ca6..db13dc7558f4 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -1705,12 +1705,16 @@ 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); + +#define tcp_twsk_md5_key(twsk) ((twsk)->tw_md5_key) 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.key)) return NULL; + if (unlikely(sk->sk_state == TCP_TIME_WAIT)) + return tcp_twsk_md5_key(tcp_twsk(sk)); return __tcp_md5_do_lookup(sk, l3index, addr, family); } @@ -1718,9 +1722,6 @@ enum skb_drop_reason tcp_inbound_md5_hash(const struct sock *sk, const struct sk_buff *skb, const void *saddr, const void *daddr, int family, int dif, int sdif); - - -#define tcp_twsk_md5_key(twsk) ((twsk)->tw_md5_key) #else static inline struct tcp_md5sig_key * tcp_md5_do_lookup(const struct sock *sk, int l3index, diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index b1056a4af60f..f5b870943dcb 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -676,7 +676,7 @@ static bool tcp_v4_md5_sign_reset(struct net *net, const struct sock *sk, return !!hash_location; rcu_read_lock(); - if (sk && sk_fullsock(sk)) { + if (sk && sk->sk_state != TCP_NEW_SYN_RECV) { const union tcp_md5_addr *addr; int l3index; @@ -2195,8 +2195,13 @@ int tcp_v4_rcv(struct sk_buff *skb) goto discard_it; do_time_wait: - if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) { + if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) drop_reason = SKB_DROP_REASON_XFRM_POLICY; + else + drop_reason = tcp_inbound_md5_hash(sk, skb, + &iph->saddr, &iph->daddr, + AF_INET, dif, sdif); + if (drop_reason) { inet_twsk_put(inet_twsk(sk)); goto discard_it; } diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c index 574398a89970..3756a43367a3 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -987,7 +987,7 @@ static int tcp_v6_md5_lookup_reset_key(struct net *net, const struct sock *sk, if (!static_branch_unlikely(&tcp_md5_needed.key)) return !!hash_location; - if (sk && sk_fullsock(sk)) { + if (sk && sk->sk_state != TCP_NEW_SYN_RECV) { /* sdif set, means packet ingressed via a device * in an L3 domain and inet_iif is set to it. */ @@ -1795,8 +1795,14 @@ INDIRECT_CALLABLE_SCOPE int tcp_v6_rcv(struct sk_buff *skb) goto discard_it; do_time_wait: - if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) { + if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) drop_reason = SKB_DROP_REASON_XFRM_POLICY; + else + drop_reason = tcp_inbound_md5_hash(sk, skb, + &hdr->saddr, &hdr->daddr, + AF_INET6, dif, sdif); + + if (drop_reason) { inet_twsk_put(inet_twsk(sk)); goto discard_it; } From patchwork Tue May 9 22:16:07 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dmitry Safonov X-Patchwork-Id: 13236199 X-Patchwork-Delegate: kuba@kernel.org 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 B654319E4B for ; 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Tue, 09 May 2023 15:16:19 -0700 (PDT) From: Dmitry Safonov To: linux-kernel@vger.kernel.org, David Ahern , Eric Dumazet , Paolo Abeni , Jakub Kicinski , "David S. Miller" Cc: Dmitry Safonov , Dmitry Safonov <0x7f454c46@gmail.com>, Hideaki YOSHIFUJI , Leonard Crestez , Salam Noureddine , netdev@vger.kernel.org Subject: [RFC 4/5] net/tcp-md5: Don't send RST if key (dis)appeared Date: Tue, 9 May 2023 23:16:07 +0100 Message-Id: <20230509221608.2569333-5-dima@arista.com> X-Mailer: git-send-email 2.40.0 In-Reply-To: <20230509221608.2569333-1-dima@arista.com> References: <20230509221608.2569333-1-dima@arista.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE, SPF_HELO_NONE,SPF_NONE,T_SCC_BODY_TEXT_LINE,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net X-Patchwork-Delegate: kuba@kernel.org X-Patchwork-State: RFC Seems cheap at this place as both key and hash_location were looked up until now. Signed-off-by: Dmitry Safonov --- net/ipv4/tcp_ipv4.c | 10 ++++++++++ net/ipv6/tcp_ipv6.c | 8 ++++++++ 2 files changed, 18 insertions(+) diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index f5b870943dcb..d94cd5e70d58 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -686,6 +686,16 @@ static bool tcp_v4_md5_sign_reset(struct net *net, const struct sock *sk, l3index = tcp_v4_sdif(skb) ? inet_iif(skb) : 0; addr = (union tcp_md5_addr *)&ip_hdr(skb)->saddr; key = tcp_md5_do_lookup(sk, l3index, addr, AF_INET); + /* This segment should have been already verified by + * tcp_inbound_md5_hash(). But that might raced with userspace + * adding or deleting keys. So, follow the logic of + * tcp_inbound_md5_hash() and avoid replying with TCP-MD5 sign + * on non-signed segments and vice-versa. + */ + if (unlikely(!!key != !!hash_location)) { + rcu_read_unlock(); + return true; + } } else if (hash_location) { const union tcp_md5_addr *addr; int sdif = tcp_v4_sdif(skb); diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c index 3756a43367a3..498dfa194b8b 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -993,6 +993,14 @@ static int tcp_v6_md5_lookup_reset_key(struct net *net, const struct sock *sk, */ l3index = tcp_v6_sdif(skb) ? tcp_v6_iif_l3_slave(skb) : 0; *key = tcp_v6_md5_do_lookup(sk, &ipv6h->saddr, l3index); + /* This segment should have been already verified by + * tcp_inbound_md5_hash(). But that might raced with userspace + * adding or deleting keys. So, follow the logic of + * tcp_inbound_md5_hash() and avoid replying with TCP-MD5 sign + * on non-signed segments and vice-versa. + */ + if (unlikely(!!*key != !!hash_location)) + return -ENOKEY; } else if (hash_location) { int dif = tcp_v6_iif_l3_slave(skb); int sdif = tcp_v6_sdif(skb); From patchwork Tue May 9 22:16:08 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dmitry Safonov X-Patchwork-Id: 13236200 X-Patchwork-Delegate: kuba@kernel.org 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 9BB1119E4B for ; Tue, 9 May 2023 22:16:23 +0000 (UTC) Received: from mail-wm1-x336.google.com (mail-wm1-x336.google.com [IPv6:2a00:1450:4864:20::336]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5220A3A87 for ; Tue, 9 May 2023 15:16:22 -0700 (PDT) Received: by mail-wm1-x336.google.com with SMTP id 5b1f17b1804b1-3f42b984405so9829635e9.3 for ; Tue, 09 May 2023 15:16:22 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=arista.com; s=google; t=1683670581; x=1686262581; 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=Lc+xA7tlcC6A/HLIGYglx4S12hhfgqdXTKqlDOHD+8g=; b=MzlgfUUAYES98I8Blt0uDfqbqzdhCiYd3z2QxUhekOknoxQbNIgpLRyzMq1Xmch7h8 HItqYCSavUCqWy6kHsNZ0BcKI0OVSRDn6fwwYEQTXfplkFaQkswuICiX2I3//M9E6kAB P2nMX2EJLEkjUiRmfAAJoiyX555vwsTfgrWbc6FYyR/Pab9SfAR5yRxBmcBmTuaTDhmf jz/2BVV0PIEB5rr4S6tBalg4PrONuoUJJVDKZoAR+ajpq3NwV9XoZ8Lq2Nc2Avbp4q9O tXCn4Yl6HwngLAP+Lu+i6S3wv4Uhh/lPDtEwx1EtJpazHkWWT3scsIQqIIemzg+mHVwv Jrdg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1683670581; x=1686262581; 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=Lc+xA7tlcC6A/HLIGYglx4S12hhfgqdXTKqlDOHD+8g=; b=GbR93vnbfIvUxTc5mrnuDVSLFYgAzW4xrmPmRO69pHNlyIiNlkAFFHzq0FmH6cK510 yeTwDa1W29rEsQ3g3WBQwZW1n13RqLRNqu0lZqhL9D1Gd8jjkbeycEwVJL7ieYbIjh+A zOxaGqZM4588G95nYtSwlREUxTJFw90AcSM8jHCwr2Ed+OH3tXbDoF40Vq1X4cEeaYeH dnajLOP7LVYtwC1ynTCehOwhMq+CHO5INa+GvvYT4u5yzjBFNkfUQOWSZoJmgGHRgZsx ptsIe9MRNE375o4Cx5R8lSHMB6UfwRMNWpt1EovvrIM/PVU8jILa5i8IaIgNBJ0BO47r Zi+Q== X-Gm-Message-State: AC+VfDx7d3ak9sBd4LkTAInCAdoofb6etj6Y3aN64FZ7D/NQUTwX7Gdx q0Tzxcm6XA+pVfWSp9GU0FQ2mA== X-Google-Smtp-Source: ACHHUZ53khA8ZUPP0QlnwjV+NGrdwIuAZcQJbHfVX3TMwqEq0wSrQhmpuHxdHD0QKJFqU+ila5I/Bg== X-Received: by 2002:a1c:f20a:0:b0:3f1:819d:d050 with SMTP id s10-20020a1cf20a000000b003f1819dd050mr10537973wmc.37.1683670580862; Tue, 09 May 2023 15:16:20 -0700 (PDT) Received: from Mindolluin.ire.aristanetworks.com ([217.173.96.166]) by smtp.gmail.com with ESMTPSA id t25-20020a7bc3d9000000b003f42d3111b8sm2052888wmj.30.2023.05.09.15.16.19 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 09 May 2023 15:16:20 -0700 (PDT) From: Dmitry Safonov To: linux-kernel@vger.kernel.org, David Ahern , Eric Dumazet , Paolo Abeni , Jakub Kicinski , "David S. Miller" Cc: Dmitry Safonov , Dmitry Safonov <0x7f454c46@gmail.com>, Hideaki YOSHIFUJI , Leonard Crestez , Salam Noureddine , netdev@vger.kernel.org Subject: [RFC 5/5] net/tcp-md5: Don't send ACK if key (dis)appears Date: Tue, 9 May 2023 23:16:08 +0100 Message-Id: <20230509221608.2569333-6-dima@arista.com> X-Mailer: git-send-email 2.40.0 In-Reply-To: <20230509221608.2569333-1-dima@arista.com> References: <20230509221608.2569333-1-dima@arista.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE, SPF_HELO_NONE,SPF_NONE,T_SCC_BODY_TEXT_LINE,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net X-Patchwork-Delegate: kuba@kernel.org X-Patchwork-State: RFC To mirror RST paranoid checks and tcp_inbound_md5_hash(). Signed-off-by: Dmitry Safonov --- net/ipv4/tcp_ipv4.c | 2 ++ net/ipv6/tcp_ipv6.c | 2 ++ 2 files changed, 4 insertions(+) diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index d94cd5e70d58..0c8893240f70 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -918,6 +918,8 @@ static void tcp_v4_send_ack(const struct sock *sk, rep.th.window = htons(win); #ifdef CONFIG_TCP_MD5SIG + if (unlikely(!!key != !!tcp_parse_md5sig_option(th))) + return; if (key) { int offset = (tsecr) ? 3 : 0; diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c index 498dfa194b8b..4131ada9fabf 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -863,6 +863,8 @@ static void tcp_v6_send_response(const struct sock *sk, struct sk_buff *skb, u32 if (tsecr) tot_len += TCPOLEN_TSTAMP_ALIGNED; #ifdef CONFIG_TCP_MD5SIG + if (!rst && unlikely(!!key != !!tcp_parse_md5sig_option(th))) + return; if (key) tot_len += TCPOLEN_MD5SIG_ALIGNED; #endif