From patchwork Tue Jul 26 06:15:27 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Leonard Crestez X-Patchwork-Id: 12928697 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 61B2BC433EF for ; Tue, 26 Jul 2022 06:21:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238024AbiGZGVP (ORCPT ); Tue, 26 Jul 2022 02:21:15 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33112 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237897AbiGZGTF (ORCPT ); Tue, 26 Jul 2022 02:19:05 -0400 Received: from mail-ed1-x52b.google.com (mail-ed1-x52b.google.com [IPv6:2a00:1450:4864:20::52b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 455712A975; Mon, 25 Jul 2022 23:16:35 -0700 (PDT) Received: by mail-ed1-x52b.google.com with SMTP id x91so16533318ede.1; Mon, 25 Jul 2022 23:16:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=kVRZdxuJ9ycX3epDnPg5nrSBdofilV3G70rXJN3b0KQ=; b=kmxy22CHBpjXpAPy4VXO03WMeRIxdnXe0dn2nZZ99jQmMns3CU804GJTf/KXaKfoB5 wHn1kb2eBX8hEP/0CpeA0uOzGRu/ZDTgpMVTyFmmkf+ebHVPhL/sv7wtVhtVXTK3UFyX ve3KoyPIH2LskNXYN3o1g0ortjJhZ4feMSYKjt8fhIkamRneOdWRaZCDVklNEBOjfWDu 6+8vxOwHhnQ8qrOJb8+ZF7RNoUVpATL7Zwje3paWOzZbpYCkjtBb3c12DJsOzpuBdBww ALEwbJdOkZ0ab8fszyjzvoSZSq76ftQjbkQGJo6UVxtiDwIDRNvqW3qclOhMlFHA7k8Y kpwA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=kVRZdxuJ9ycX3epDnPg5nrSBdofilV3G70rXJN3b0KQ=; b=0tTR8xmjKEj7ivXaWvRA4fy8M/7NRSop44jssApDX6vAFX2fJubCAEBWwSMSVdfTQJ KK2H/1G6JOKKjbgJi6OIgjEu0b+VHh76JnPe5YBalheeMTX016RcZ/BQtv5PamYGzvpG mteAkQQdKwp9qPe0S3nwQdDFu/CSjHB7+ZeDuw1VPrHIc5+6RQUVq8/i7j5jCXRxXlHA OZTZMqXJMeSoQYRfJo5gKQTM7JTJTK+y++ULRWXcdW55ZjEWtyBkwOLs3kUduXADbuTF MiTW/v/D3No4kfDPzKWPfLLfMScype6x4Vryp1FuzEmxHovA55Ckrp9AUdAVCe6f3xdo YhBg== X-Gm-Message-State: AJIora9JH425qhhz5nhUPgbrCRTpaS81w18AZYRZUn0KXb4yysfLu4VH olLQqCzEO/3o4NoPzhBWptUAaybl0DZT9g== X-Google-Smtp-Source: AGRyM1t8TsoBy85dJWLHWS7wjzqAv4uT8oQ/dMWQ80ZGJ3O1yXkm8Ta0emAegg+7H36zItDRbXSKNA== X-Received: by 2002:aa7:c0d0:0:b0:43b:b6d5:2977 with SMTP id j16-20020aa7c0d0000000b0043bb6d52977mr16764435edp.199.1658816185449; Mon, 25 Jul 2022 23:16:25 -0700 (PDT) Received: from localhost.localdomain ([2a04:241e:502:a080:2b68:36a:5a94:4ba1]) by smtp.gmail.com with ESMTPSA id l23-20020a056402345700b0043ba7df7a42sm8133067edc.26.2022.07.25.23.16.23 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 25 Jul 2022 23:16:25 -0700 (PDT) From: Leonard Crestez To: David Ahern , Eric Dumazet , Philip Paeps Cc: Dmitry Safonov <0x7f454c46@gmail.com>, Shuah Khan , "David S. Miller" , Herbert Xu , Kuniyuki Iwashima , Hideaki YOSHIFUJI , Jakub Kicinski , Yuchung Cheng , Francesco Ruggeri , Mat Martineau , Christoph Paasch , Ivan Delalande , Caowangbao , Priyaranjan Jha , netdev@vger.kernel.org, linux-crypto@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v6 25/26] tcp: authopt: If no keys are valid for send report an error Date: Tue, 26 Jul 2022 09:15:27 +0300 Message-Id: <09b6b75d04cf4a439cf84a6d50dcf641c9d727bc.1658815925.git.cdleonard@gmail.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: References: MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org If this is not treated specially then when all keys are removed or expired then TCP will start sending unsigned packets which is undesirable. Instead try to report an error on key selection and propagate it to userspace. The error is assigned to sk_err and propagate it as soon as possible. In theory we could try to make the error "soft" and even let the connection continue if userspace adds a new key but the advantages are unclear. Since userspace is responsible for managing keys it can also avoid sending unsigned packets by always closing the socket before removing the active last key. The specific error reported is ENOKEY. This requires changes inside TCP option write code to support aborting the actual packet send, until this point this did not happen in any scenario. Signed-off-by: Leonard Crestez --- net/ipv4/tcp_authopt.c | 9 +++++++-- net/ipv4/tcp_output.c | 20 ++++++++++++++++++++ 2 files changed, 27 insertions(+), 2 deletions(-) diff --git a/net/ipv4/tcp_authopt.c b/net/ipv4/tcp_authopt.c index e162e5944ec5..c71f5ed5ca1d 100644 --- a/net/ipv4/tcp_authopt.c +++ b/net/ipv4/tcp_authopt.c @@ -439,10 +439,11 @@ struct tcp_authopt_key_info *__tcp_authopt_select_key(const struct sock *sk, u8 *rnextkeyid, bool locked) { struct tcp_authopt_key_info *key, *new_key = NULL; struct netns_tcp_authopt *net = sock_net_tcp_authopt(sk); + bool anykey = false; /* Listen sockets don't refer to any specific connection so we don't try * to keep using the same key. * The rnextkeyid is stored in tcp_request_sock */ @@ -461,11 +462,13 @@ struct tcp_authopt_key_info *__tcp_authopt_select_key(const struct sock *sk, else send_id = rsk->recv_rnextkeyid; key = tcp_authopt_lookup_send(net, addr_sk, send_id, NULL); /* If no key found with specific send_id try anything else. */ if (!key) - key = tcp_authopt_lookup_send(net, addr_sk, -1, NULL); + key = tcp_authopt_lookup_send(net, addr_sk, -1, &anykey); + if (!key && anykey) + return ERR_PTR(-ENOKEY); if (key) *rnextkeyid = key->recv_id; return key; } @@ -497,11 +500,13 @@ struct tcp_authopt_key_info *__tcp_authopt_select_key(const struct sock *sk, info->recv_rnextkeyid, NULL); } /* If no key found with specific send_id try anything else. */ if (!key && !new_key) - new_key = tcp_authopt_lookup_send(net, addr_sk, -1, NULL); + new_key = tcp_authopt_lookup_send(net, addr_sk, -1, &anykey); + if (!new_key && anykey) + return ERR_PTR(-ENOKEY); /* Update current key only if we hold the socket lock. */ if (new_key && key != new_key) { if (locked) { if (kref_get_unless_zero(&new_key->ref)) { diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index 0ab3c7801f33..b8dab313af0f 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -414,10 +414,11 @@ static inline bool tcp_urg_mode(const struct tcp_sock *tp) #define OPTION_SACK_ADVERTISE BIT(0) #define OPTION_TS BIT(1) #define OPTION_MD5 BIT(2) #define OPTION_WSCALE BIT(3) #define OPTION_AUTHOPT BIT(4) +#define OPTION_AUTHOPT_FAIL BIT(5) #define OPTION_FAST_OPEN_COOKIE BIT(8) #define OPTION_SMC BIT(9) #define OPTION_MPTCP BIT(10) static void smc_options_write(__be32 *ptr, u16 *options) @@ -786,10 +787,14 @@ static int tcp_authopt_init_options(const struct sock *sk, { #ifdef CONFIG_TCP_AUTHOPT struct tcp_authopt_key_info *key; key = tcp_authopt_select_key(sk, addr_sk, &opts->authopt_info, &opts->authopt_rnextkeyid); + if (IS_ERR(key)) { + opts->options |= OPTION_AUTHOPT_FAIL; + return TCPOLEN_AUTHOPT_OUTPUT; + } if (key) { opts->options |= OPTION_AUTHOPT; opts->authopt_key = key; return TCPOLEN_AUTHOPT_OUTPUT; } @@ -1345,10 +1350,18 @@ static int __tcp_transmit_skb(struct sock *sk, struct sk_buff *skb, * release the following packet. */ if (tcp_skb_pcount(skb) > 1) tcb->tcp_flags |= TCPHDR_PSH; } +#ifdef CONFIG_TCP_AUTHOPT + if (opts.options & OPTION_AUTHOPT_FAIL) { + rcu_read_unlock(); + sk->sk_err = ENOKEY; + sk_error_report(sk); + return -ENOKEY; + } +#endif tcp_header_size = tcp_options_size + sizeof(struct tcphdr); /* if no packet is in qdisc/device queue, then allow XPS to select * another queue. We can be called from tcp_tsq_handler() * which holds one reference to sk. @@ -3655,10 +3668,17 @@ struct sk_buff *tcp_make_synack(const struct sock *sk, struct dst_entry *dst, /* bpf program will be interested in the tcp_flags */ TCP_SKB_CB(skb)->tcp_flags = TCPHDR_SYN | TCPHDR_ACK; tcp_header_size = tcp_synack_options(sk, req, mss, skb, &opts, md5, foc, synack_type, syn_skb) + sizeof(*th); +#ifdef CONFIG_TCP_AUTHOPT + if (opts.options & OPTION_AUTHOPT_FAIL) { + rcu_read_unlock(); + kfree_skb(skb); + return NULL; + } +#endif skb_push(skb, tcp_header_size); skb_reset_transport_header(skb); th = (struct tcphdr *)skb->data;