From patchwork Mon Jun 10 20:41:19 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stephen Suryaputra X-Patchwork-Id: 1113309 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming-netdev@ozlabs.org Delivered-To: patchwork-incoming-netdev@ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=netdev-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=gmail.com header.i=@gmail.com header.b="myzWyc7I"; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 45N4mm03xgz9s6w for ; Tue, 11 Jun 2019 06:41:44 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389725AbfFJUlm (ORCPT ); Mon, 10 Jun 2019 16:41:42 -0400 Received: from mail-pf1-f195.google.com ([209.85.210.195]:40303 "EHLO mail-pf1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389429AbfFJUlm (ORCPT ); Mon, 10 Jun 2019 16:41:42 -0400 Received: by mail-pf1-f195.google.com with SMTP id p184so2669213pfp.7 for ; Mon, 10 Jun 2019 13:41:42 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id; bh=uEbaWZ7CSywpPD1njQAxIRl3QQVRG3+Pm3u0i4SdA7w=; b=myzWyc7IzQ40a7FYnmsy4R+mEd/DohReFfNuXXS2dJlHE57HgEJrojUoWcJSQEDj0Y Nc2Jm8Gv4tMaqB+TRfFyxU4r0QrdBDPgTY+FBAgAvOIkraVh7ldd9Z2huEm1Qc3jtbrD Nan4k3zkno6QUkIxb1DtYh1KPcpcY6LCiiXzME+CF0tDFHGFaALqkvHzavRIAQoNX3jX NMTvhSTvf5u7V4lcTelauGmwUta9WycWIjsABNW5CnyBKi4oeiFrVa+jsBN9pYD1lHn1 EmxfGR/W2jJHov3e6vNCmvN96mKyd38CZNkHhf4ZHu/VedzJu9sG+rjvjRgrwhbBV3q+ oYAA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id; bh=uEbaWZ7CSywpPD1njQAxIRl3QQVRG3+Pm3u0i4SdA7w=; b=mnDY7UmFdAqQWB0RFS64Jn30UQXJifReVb81pDY1EC9BhRNmsqUWX3p6gxrnVN97rd 3uQ0ZooTSOVDxYFvXEQtZxpSLvTzjv6h4SK7rSScs+wn+2opY9TMLKUc8rLlCygGAXel 5rpQb4JjLwkm8T8y2k6T3v+DB88Nyg6gY5eG5igMPKlp1w8KEsByPwMnU04JIEaCtUXw uArxBWM85ZcEVOev0CuCxqfxxLeROzpJJdykWAPousnFnwnfP1aonCWLLEdCGxkaOdsh v4J/ZkU2j9bJDPwRanPDaUBLv5HKB+h4dcHyLPvOYDUU6anmCubTC8YQvcDnNejeBID9 YugA== X-Gm-Message-State: APjAAAXih0AZ/L+WAaJX1UFaU0bMhRvvLSP7/+f9k+glpyL51SiJiMa8 YJiQFhP8eUAR/aQL3ChOfK7SPGE= X-Google-Smtp-Source: APXvYqxsHhoTco5L4MFYCcu/BFDFRnFBvpKhmq4S2+r8GXgwsAi5wWYj1MzB/eUw2wGXsCKsmVrE4Q== X-Received: by 2002:a63:4d05:: with SMTP id a5mr16094072pgb.19.1560199301222; Mon, 10 Jun 2019 13:41:41 -0700 (PDT) Received: from ubuntu.extremenetworks.com ([12.38.14.8]) by smtp.gmail.com with ESMTPSA id y19sm12580455pfe.150.2019.06.10.13.41.38 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 10 Jun 2019 13:41:40 -0700 (PDT) From: Stephen Suryaputra To: netdev@vger.kernel.org Cc: Stephen Suryaputra Subject: [PATCH nf-next v2] netfilter: add support for matching IPv4 options Date: Mon, 10 Jun 2019 16:41:19 -0400 Message-Id: <20190610204119.26747-1-ssuryaextr@gmail.com> X-Mailer: git-send-email 2.17.1 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org This is the kernel change for the overall changes with this description: Add capability to have rules matching IPv4 options. This is developed mainly to support dropping of IP packets with loose and/or strict source route route options. Nevertheless, the implementation include others and ability to get specific fields in the option. v2: Fix style issues. Make this work with NFPROTO_INET (inet tables), NFPROTO_BRIDGE and the NFPROTO_NETDEV families. Check skb->protocol. Remove ability to input IP header offset for ipv4_find_option() function (all per Pablo Neira Ayuso). Signed-off-by: Stephen Suryaputra --- include/net/inet_sock.h | 2 +- include/uapi/linux/netfilter/nf_tables.h | 2 + net/ipv4/ip_options.c | 2 + net/netfilter/nft_exthdr.c | 133 +++++++++++++++++++++++ 4 files changed, 138 insertions(+), 1 deletion(-) diff --git a/include/net/inet_sock.h b/include/net/inet_sock.h index e8eef85006aa..8db4f8639a33 100644 --- a/include/net/inet_sock.h +++ b/include/net/inet_sock.h @@ -55,7 +55,7 @@ struct ip_options { ts_needaddr:1; unsigned char router_alert; unsigned char cipso; - unsigned char __pad2; + unsigned char end; unsigned char __data[0]; }; diff --git a/include/uapi/linux/netfilter/nf_tables.h b/include/uapi/linux/netfilter/nf_tables.h index 505393c6e959..168d741f42c5 100644 --- a/include/uapi/linux/netfilter/nf_tables.h +++ b/include/uapi/linux/netfilter/nf_tables.h @@ -730,10 +730,12 @@ enum nft_exthdr_flags { * * @NFT_EXTHDR_OP_IPV6: match against ipv6 extension headers * @NFT_EXTHDR_OP_TCP: match against tcp options + * @NFT_EXTHDR_OP_IPV4: match against ipv4 options */ enum nft_exthdr_op { NFT_EXTHDR_OP_IPV6, NFT_EXTHDR_OP_TCPOPT, + NFT_EXTHDR_OP_IPV4, __NFT_EXTHDR_OP_MAX }; #define NFT_EXTHDR_OP_MAX (__NFT_EXTHDR_OP_MAX - 1) diff --git a/net/ipv4/ip_options.c b/net/ipv4/ip_options.c index 3db31bb9df50..fc0e694aa97c 100644 --- a/net/ipv4/ip_options.c +++ b/net/ipv4/ip_options.c @@ -272,6 +272,7 @@ int __ip_options_compile(struct net *net, for (l = opt->optlen; l > 0; ) { switch (*optptr) { case IPOPT_END: + opt->end = optptr - iph; for (optptr++, l--; l > 0; optptr++, l--) { if (*optptr != IPOPT_END) { *optptr = IPOPT_END; @@ -473,6 +474,7 @@ int __ip_options_compile(struct net *net, *info = htonl((pp_ptr-iph)<<24); return -EINVAL; } +EXPORT_SYMBOL(__ip_options_compile); int ip_options_compile(struct net *net, struct ip_options *opt, struct sk_buff *skb) diff --git a/net/netfilter/nft_exthdr.c b/net/netfilter/nft_exthdr.c index a940c9fd9045..4155a32fade7 100644 --- a/net/netfilter/nft_exthdr.c +++ b/net/netfilter/nft_exthdr.c @@ -62,6 +62,125 @@ static void nft_exthdr_ipv6_eval(const struct nft_expr *expr, regs->verdict.code = NFT_BREAK; } +/* find the offset to specified option or the header beyond the options + * if target < 0. + * + * If target header is found, its offset is set in *offset and return option + * number. Otherwise, return negative error. + * + * If the first fragment doesn't contain the End of Options it is considered + * invalid. + */ +static int ipv4_find_option(struct net *net, struct sk_buff *skb, + unsigned int *offset, int target, + unsigned short *fragoff, int *flags) +{ + unsigned char optbuf[sizeof(struct ip_options) + 41]; + struct ip_options *opt = (struct ip_options *)optbuf; + struct iphdr *iph, _iph; + unsigned int start; + bool found = false; + __be32 info; + int optlen; + + if (fragoff) + *fragoff = 0; + + iph = skb_header_pointer(skb, 0, sizeof(_iph), &_iph); + if (!iph || iph->version != 4) + return -EBADMSG; + start = sizeof(struct iphdr); + + optlen = iph->ihl * 4 - (int)sizeof(struct iphdr); + if (optlen <= 0) + return -ENOENT; + + memset(opt, 0, sizeof(struct ip_options)); + /* Copy the options since __ip_options_compile() modifies + * the options. Get one byte beyond the option for target < 0 + */ + if (skb_copy_bits(skb, start, opt->__data, optlen + 1)) + return -EBADMSG; + opt->optlen = optlen; + + if (__ip_options_compile(net, opt, NULL, &info)) + return -EBADMSG; + + switch (target) { + case IPOPT_SSRR: + case IPOPT_LSRR: + if (!opt->srr) + break; + found = target == IPOPT_SSRR ? opt->is_strictroute : + !opt->is_strictroute; + if (found) + *offset = opt->srr + start; + break; + case IPOPT_RR: + if (opt->rr) + break; + *offset = opt->rr + start; + found = true; + break; + case IPOPT_RA: + if (opt->router_alert) + break; + *offset = opt->router_alert + start; + found = true; + break; + default: + /* Either not supported or not a specific search, treated as + * found + */ + found = true; + if (target >= 0) { + target = -EOPNOTSUPP; + break; + } + if (opt->end) { + *offset = opt->end + start; + target = IPOPT_END; + } else { + /* Point to beyond the options. */ + *offset = optlen + start; + target = opt->__data[optlen]; + } + } + if (!found) + target = -ENOENT; + return target; +} + +static void nft_exthdr_ipv4_eval(const struct nft_expr *expr, + struct nft_regs *regs, + const struct nft_pktinfo *pkt) +{ + struct nft_exthdr *priv = nft_expr_priv(expr); + u32 *dest = ®s->data[priv->dreg]; + struct sk_buff *skb = pkt->skb; + unsigned int offset; + int err; + + if (skb->protocol != htons(ETH_P_IP)) + goto err; + + err = ipv4_find_option(nft_net(pkt), skb, &offset, priv->type, NULL, NULL); + if (priv->flags & NFT_EXTHDR_F_PRESENT) { + *dest = (err >= 0); + return; + } else if (err < 0) { + goto err; + } + offset += priv->offset; + + dest[priv->len / NFT_REG32_SIZE] = 0; + if (skb_copy_bits(pkt->skb, offset, dest, priv->len) < 0) + goto err; + return; +err: + regs->verdict.code = NFT_BREAK; +} + static void * nft_tcp_header_pointer(const struct nft_pktinfo *pkt, unsigned int len, void *buffer, unsigned int *tcphdr_len) @@ -360,6 +479,14 @@ static const struct nft_expr_ops nft_exthdr_ipv6_ops = { .dump = nft_exthdr_dump, }; +static const struct nft_expr_ops nft_exthdr_ipv4_ops = { + .type = &nft_exthdr_type, + .size = NFT_EXPR_SIZE(sizeof(struct nft_exthdr)), + .eval = nft_exthdr_ipv4_eval, + .init = nft_exthdr_init, + .dump = nft_exthdr_dump, +}; + static const struct nft_expr_ops nft_exthdr_tcp_ops = { .type = &nft_exthdr_type, .size = NFT_EXPR_SIZE(sizeof(struct nft_exthdr)), @@ -400,6 +527,12 @@ nft_exthdr_select_ops(const struct nft_ctx *ctx, if (tb[NFTA_EXTHDR_DREG]) return &nft_exthdr_ipv6_ops; break; + case NFT_EXTHDR_OP_IPV4: + if (ctx->family != NFPROTO_IPV6) { + if (tb[NFTA_EXTHDR_DREG]) + return &nft_exthdr_ipv4_ops; + } + break; } return ERR_PTR(-EOPNOTSUPP);