From patchwork Thu Dec 23 15:40:10 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Leonard Crestez X-Patchwork-Id: 527490 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 0FE9FC433EF for ; Thu, 23 Dec 2021 15:41:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1349190AbhLWPlc (ORCPT ); Thu, 23 Dec 2021 10:41:32 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33938 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1349103AbhLWPlH (ORCPT ); Thu, 23 Dec 2021 10:41:07 -0500 Received: from mail-ed1-x534.google.com (mail-ed1-x534.google.com [IPv6:2a00:1450:4864:20::534]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EEDD4C061792; Thu, 23 Dec 2021 07:41:06 -0800 (PST) Received: by mail-ed1-x534.google.com with SMTP id m21so24214737edc.0; Thu, 23 Dec 2021 07:41:06 -0800 (PST) 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=rEhPZkA/AwOo/pza/2HZJSP1cTNQTQZNl+J27uwUZ7g=; b=WsIW1hysqf398eRsPZ+fFAL7c2qABZUk5IrbaaLan7cwW15pw18ouzu7uqnBan4axr BW6BT2AIvwnHGYoJ2rrjYdOHuYQ6NmHuQLu7iOXzrC6mrLgd8aYBuBW7bPEV682oxa+n /BOBR3rORac6KTEGDlROhrO4yWoKWCtJsMif4965W+xm5Rt2DLiYb6NawPs+4p2ALBX1 ChuIhrhNz4oYsP5EKUJtYVmocoty5mA+f1d/3HefI3acOCBlaRhy10Z+fZnJhHMD+hYL gth1QQ/nQCygcDqfoG/kPj45anp0EEj62K4YG9/B6QFIEfa4Y6cPw0mwQkGl1bSXGxSx pFrw== 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=rEhPZkA/AwOo/pza/2HZJSP1cTNQTQZNl+J27uwUZ7g=; b=sI7YQ4N6OiEdw5258m8zWQJrWPPDeGE+zWXhFwYs9bmuGA55VyEGzADE2I7/tVx9I1 WeRnWzsw1b/BnuXuZRl4mBiooYxmeUgqSnfB6ALlpUAC72+WxV7lLmhHWyw7dvAl8423 ZQZDKQbCxnAH6H1undlODwZSyVYkCd6kb7S62B+CY2cLzghLkNUmQqUIpixgpPODOHee V0hchPnDPvqZWuAW6hcayvhgSdowKg5KVetN3SOAnQMdkjUDDURSJVavTRkbpxmJnbiw FNgloUlammKjSk5vVOSd92vMl+L07mlrJacD1Z+Fy+qJHXK2hFpEwlqDdZEu6tl7F2Hz ZNVA== X-Gm-Message-State: AOAM532BOs1oP2GfUhI4U1dffD9qQpUViKSr+5sS5TZ1JxYzyqKjBJjI OmGzktL/m9IwkZS12B3Z9XA= X-Google-Smtp-Source: ABdhPJysF1sO2gThsWcUfiaskTEUc/nRXerkqu/ktvs+bqvLrAbTBDZ6aQDpX2yWVuH9b2/FNr7S9g== X-Received: by 2002:a17:906:4790:: with SMTP id cw16mr2299544ejc.493.1640274065280; Thu, 23 Dec 2021 07:41:05 -0800 (PST) Received: from ponky.lan ([2a04:241e:501:3870:7c02:dfc6:b554:ab10]) by smtp.gmail.com with ESMTPSA id bx6sm2088617edb.78.2021.12.23.07.41.03 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 23 Dec 2021 07:41:04 -0800 (PST) From: Leonard Crestez To: David Ahern , Eric Dumazet , Philip Paeps , Dmitry Safonov <0x7f454c46@gmail.com> Cc: Shuah Khan , "David S. Miller" , Herbert Xu , Kuniyuki Iwashima , Hideaki YOSHIFUJI , Jakub Kicinski , Yuchung Cheng , Francesco Ruggeri , Mat Martineau , Christoph Paasch , Ivan Delalande , Priyaranjan Jha , netdev@vger.kernel.org, linux-crypto@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v4 15/19] tcp: authopt: Add prefixlen support Date: Thu, 23 Dec 2021 17:40:10 +0200 Message-Id: <1d918bde7fdb13a05c899e519e833671cb5fbe5a.1640273966.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: linux-crypto@vger.kernel.org This allows making a key apply to an addr/prefix instead of just the full addr. This is enabled through a custom flag, default behavior is still full address match. This is equivalent to TCP_MD5SIG_FLAG_PREFIX from TCP_MD5SIG and has the same use-cases. Signed-off-by: Leonard Crestez --- Documentation/networking/tcp_authopt.rst | 1 + include/net/tcp_authopt.h | 2 + include/uapi/linux/tcp.h | 10 ++++ net/ipv4/tcp_authopt.c | 63 ++++++++++++++++++++++-- 4 files changed, 72 insertions(+), 4 deletions(-) diff --git a/Documentation/networking/tcp_authopt.rst b/Documentation/networking/tcp_authopt.rst index f681d2221ce3..6520c6d02755 100644 --- a/Documentation/networking/tcp_authopt.rst +++ b/Documentation/networking/tcp_authopt.rst @@ -38,10 +38,11 @@ new flags. * Address binding is optional, by default keys match all addresses * Local address is ignored, matching is done by remote address * Ports are ignored * It is possible to match a specific VRF by l3index (default is to ignore) + * It is possible to match with a fixed prefixlen (default is full address) RFC5925 requires that key ids do not overlap when tcp identifiers (addr/port) overlap. This is not enforced by linux, configuring ambiguous keys will result in packet drops and lost connections. diff --git a/include/net/tcp_authopt.h b/include/net/tcp_authopt.h index 800fde277239..743248904552 100644 --- a/include/net/tcp_authopt.h +++ b/include/net/tcp_authopt.h @@ -47,10 +47,12 @@ struct tcp_authopt_key_info { u8 keylen; /** @key: Same as &tcp_authopt_key.key */ u8 key[TCP_AUTHOPT_MAXKEYLEN]; /** @l3index: Same as &tcp_authopt_key.ifindex */ int l3index; + /** @prefix: Length of addr match (default full) */ + int prefixlen; /** @addr: Same as &tcp_authopt_key.addr */ struct sockaddr_storage addr; /** @alg: Algorithm implementation matching alg_id */ struct tcp_authopt_alg_imp *alg; }; diff --git a/include/uapi/linux/tcp.h b/include/uapi/linux/tcp.h index ed27feb93b0e..b1063e1e1b9f 100644 --- a/include/uapi/linux/tcp.h +++ b/include/uapi/linux/tcp.h @@ -403,18 +403,21 @@ struct tcp_authopt { * @TCP_AUTHOPT_KEY_EXCLUDE_OPTS: Exclude TCP options from signature * @TCP_AUTHOPT_KEY_ADDR_BIND: Key only valid for `tcp_authopt.addr` * @TCP_AUTHOPT_KEY_IFINDEX: Key only valid for `tcp_authopt.ifindex` * @TCP_AUTHOPT_KEY_NOSEND: Key invalid for send (expired) * @TCP_AUTHOPT_KEY_NORECV: Key invalid for recv (expired) + * @TCP_AUTHOPT_KEY_PREFIXLEN: Valid value in `tcp_authopt.prefixlen`, otherwise + * match full address length */ enum tcp_authopt_key_flag { TCP_AUTHOPT_KEY_DEL = (1 << 0), TCP_AUTHOPT_KEY_EXCLUDE_OPTS = (1 << 1), TCP_AUTHOPT_KEY_ADDR_BIND = (1 << 2), TCP_AUTHOPT_KEY_IFINDEX = (1 << 3), TCP_AUTHOPT_KEY_NOSEND = (1 << 4), TCP_AUTHOPT_KEY_NORECV = (1 << 5), + TCP_AUTHOPT_KEY_PREFIXLEN = (1 << 6), }; /** * enum tcp_authopt_alg - Algorithms for TCP Authentication Option */ @@ -465,10 +468,17 @@ struct tcp_authopt_key { * connections through this interface. Interface must be an vrf master. * * This is similar to `tcp_msg5sig.tcpm_ifindex` */ int ifindex; + /** + * @prefixlen: length of prefix to match + * + * Without the TCP_AUTHOPT_KEY_PREFIXLEN flag this is ignored and a full + * address match is performed. + */ + int prefixlen; }; /* setsockopt(fd, IPPROTO_TCP, TCP_ZEROCOPY_RECEIVE, ...) */ #define TCP_RECEIVE_ZEROCOPY_FLAG_TLB_CLEAN_HINT 0x1 diff --git a/net/ipv4/tcp_authopt.c b/net/ipv4/tcp_authopt.c index c598f3cf72d5..64bcb2a38472 100644 --- a/net/ipv4/tcp_authopt.c +++ b/net/ipv4/tcp_authopt.c @@ -4,10 +4,11 @@ #include #include #include #include #include +#include /* This is mainly intended to protect against local privilege escalations through * a rarely used feature so it is deliberately not namespaced. */ int sysctl_tcp_authopt; @@ -266,10 +267,14 @@ static bool tcp_authopt_key_match_exact(struct tcp_authopt_key_info *info, return false; if ((info->flags & TCP_AUTHOPT_KEY_IFINDEX) != (key->flags & TCP_AUTHOPT_KEY_IFINDEX)) return false; if ((info->flags & TCP_AUTHOPT_KEY_IFINDEX) && info->l3index != key->ifindex) return false; + if ((info->flags & TCP_AUTHOPT_KEY_PREFIXLEN) != (key->flags & TCP_AUTHOPT_KEY_PREFIXLEN)) + return false; + if ((info->flags & TCP_AUTHOPT_KEY_PREFIXLEN) && info->prefixlen != key->prefixlen) + return false; if ((info->flags & TCP_AUTHOPT_KEY_ADDR_BIND) != (key->flags & TCP_AUTHOPT_KEY_ADDR_BIND)) return false; if (info->flags & TCP_AUTHOPT_KEY_ADDR_BIND) if (!ipvx_addr_match(&info->addr, &key->addr)) return false; @@ -283,17 +288,20 @@ static bool tcp_authopt_key_match_skb_addr(struct tcp_authopt_key_info *key, u16 keyaf = key->addr.ss_family; struct iphdr *iph = (struct iphdr *)skb_network_header(skb); if (keyaf == AF_INET && iph->version == 4) { struct sockaddr_in *key_addr = (struct sockaddr_in *)&key->addr; + __be32 mask = inet_make_mask(key->prefixlen); - return iph->saddr == key_addr->sin_addr.s_addr; + return (iph->saddr & mask) == key_addr->sin_addr.s_addr; } else if (keyaf == AF_INET6 && iph->version == 6) { struct ipv6hdr *ip6h = (struct ipv6hdr *)skb_network_header(skb); struct sockaddr_in6 *key_addr = (struct sockaddr_in6 *)&key->addr; - return ipv6_addr_equal(&ip6h->saddr, &key_addr->sin6_addr); + return ipv6_prefix_equal(&ip6h->saddr, + &key_addr->sin6_addr, + key->prefixlen); } /* This actually happens with ipv6-mapped-ipv4-addresses * IPv6 listen sockets will be asked to validate ipv4 packets. */ @@ -309,16 +317,19 @@ static bool tcp_authopt_key_match_sk_addr(struct tcp_authopt_key_info *key, if (keyaf != addr_sk->sk_family) return false; if (keyaf == AF_INET) { struct sockaddr_in *key_addr = (struct sockaddr_in *)&key->addr; + __be32 mask = inet_make_mask(key->prefixlen); - return addr_sk->sk_daddr == key_addr->sin_addr.s_addr; + return (addr_sk->sk_daddr & mask) == key_addr->sin_addr.s_addr; } else if (keyaf == AF_INET6) { struct sockaddr_in6 *key_addr = (struct sockaddr_in6 *)&key->addr; - return ipv6_addr_equal(&addr_sk->sk_v6_daddr, &key_addr->sin6_addr); + return ipv6_prefix_equal(&addr_sk->sk_v6_daddr, + &key_addr->sin6_addr, + key->prefixlen); } return false; } @@ -343,10 +354,16 @@ static bool better_key_match(struct tcp_authopt_key_info *old, struct tcp_authop /* l3index always overrides non-l3index */ if (old->l3index && new->l3index == 0) return false; if (old->l3index == 0 && new->l3index) return true; + /* Full address match overrides match by prefixlen */ + if (!(new->flags & TCP_AUTHOPT_KEY_PREFIXLEN) && (old->flags & TCP_AUTHOPT_KEY_PREFIXLEN)) + return false; + /* Longer prefixes are better matches */ + if (new->prefixlen > old->prefixlen) + return true; return false; } static struct tcp_authopt_key_info *tcp_authopt_lookup_send(struct netns_tcp_authopt *net, @@ -610,21 +627,32 @@ int tcp_get_authopt_val(struct sock *sk, struct tcp_authopt *opt) #define TCP_AUTHOPT_KEY_KNOWN_FLAGS ( \ TCP_AUTHOPT_KEY_DEL | \ TCP_AUTHOPT_KEY_EXCLUDE_OPTS | \ TCP_AUTHOPT_KEY_ADDR_BIND | \ TCP_AUTHOPT_KEY_IFINDEX | \ + TCP_AUTHOPT_KEY_PREFIXLEN | \ TCP_AUTHOPT_KEY_NOSEND | \ TCP_AUTHOPT_KEY_NORECV) +static bool ipv6_addr_is_prefix(struct in6_addr *addr, int plen) +{ + struct in6_addr copy; + + ipv6_addr_prefix_copy(©, addr, plen); + + return !!memcmp(©, addr, sizeof(*addr)); +} + int tcp_set_authopt_key(struct sock *sk, sockptr_t optval, unsigned int optlen) { struct tcp_authopt_key opt; struct tcp_authopt_info *info; struct tcp_authopt_key_info *key_info, *old_key_info; struct netns_tcp_authopt *net = sock_net_tcp_authopt(sk); struct tcp_authopt_alg_imp *alg; int l3index = 0; + int prefixlen; int err; sock_owned_by_me(sk); err = check_sysctl_tcp_authopt(); if (err) @@ -660,10 +688,36 @@ int tcp_set_authopt_key(struct sock *sk, sockptr_t optval, unsigned int optlen) if (opt.flags & TCP_AUTHOPT_KEY_ADDR_BIND) { if (sk->sk_family != opt.addr.ss_family) return -EINVAL; } + /* check prefixlen */ + if (opt.flags & TCP_AUTHOPT_KEY_PREFIXLEN) { + prefixlen = opt.prefixlen; + if (sk->sk_family == AF_INET) { + if (prefixlen < 0 || prefixlen > 32) + return -EINVAL; + if (((struct sockaddr_in *)&opt.addr)->sin_addr.s_addr & + ~inet_make_mask(prefixlen)) + return -EINVAL; + } + if (sk->sk_family == AF_INET6) { + if (prefixlen < 0 || prefixlen > 128) + return -EINVAL; + if (!ipv6_addr_is_prefix(&((struct sockaddr_in6 *)&opt.addr)->sin6_addr, + prefixlen)) + return -EINVAL; + } + } else { + if (sk->sk_family == AF_INET) + prefixlen = 32; + else if (sk->sk_family == AF_INET6) + prefixlen = 128; + else + return -EINVAL; + } + /* Initialize tcp_authopt_info if not already set */ info = __tcp_authopt_info_get_or_create(sk); if (IS_ERR(info)) return PTR_ERR(info); @@ -709,10 +763,11 @@ int tcp_set_authopt_key(struct sock *sk, sockptr_t optval, unsigned int optlen) key_info->alg = alg; key_info->keylen = opt.keylen; memcpy(key_info->key, opt.key, opt.keylen); memcpy(&key_info->addr, &opt.addr, sizeof(key_info->addr)); key_info->l3index = l3index; + key_info->prefixlen = prefixlen; hlist_add_head_rcu(&key_info->node, &net->head); mutex_unlock(&net->mutex); return 0; }