From patchwork Fri Dec 13 12:18:01 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "fan.du" X-Patchwork-Id: 300998 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 128CA2C00A1 for ; Fri, 13 Dec 2013 23:18:29 +1100 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752742Ab3LMMSW (ORCPT ); Fri, 13 Dec 2013 07:18:22 -0500 Received: from mail1.windriver.com ([147.11.146.13]:52467 "EHLO mail1.windriver.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752568Ab3LMMSR (ORCPT ); Fri, 13 Dec 2013 07:18:17 -0500 Received: from ALA-HCB.corp.ad.wrs.com (ala-hcb.corp.ad.wrs.com [147.11.189.41]) by mail1.windriver.com (8.14.5/8.14.5) with ESMTP id rBDCI6NX006955 (version=TLSv1/SSLv3 cipher=AES128-SHA bits=128 verify=FAIL); Fri, 13 Dec 2013 04:18:07 -0800 (PST) Received: from iamroot-OptiPlex-780.corp.ad.wrs.com (128.224.162.238) by ALA-HCB.corp.ad.wrs.com (147.11.189.41) with Microsoft SMTP Server id 14.2.347.0; Fri, 13 Dec 2013 04:18:06 -0800 From: Fan Du To: CC: , , , Subject: [PATCH 1/2] netfilter: add IPv4 IPComp extension match support Date: Fri, 13 Dec 2013 20:18:01 +0800 Message-ID: <1386937082-30412-2-git-send-email-fan.du@windriver.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1386937082-30412-1-git-send-email-fan.du@windriver.com> References: <1386937082-30412-1-git-send-email-fan.du@windriver.com> MIME-Version: 1.0 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org With this plugin, user could specify IPComp tagged with certain CPI that host not interested will be DROPped or any other action. For example: iptables -A INPUT -p 108 -m ipcomp --ipcompspi 0x87 -j DROP Then input IPComp packet with CPI equates 0x87 will not reach upper layer anymore. Signed-off-by: Fan Du --- include/uapi/linux/netfilter_ipv4/ipt_comp.h | 18 +++++ net/ipv4/netfilter/Kconfig | 9 +++ net/ipv4/netfilter/Makefile | 1 + net/ipv4/netfilter/ipt_comp.c | 101 ++++++++++++++++++++++++++ 4 files changed, 129 insertions(+) create mode 100644 include/uapi/linux/netfilter_ipv4/ipt_comp.h create mode 100644 net/ipv4/netfilter/ipt_comp.c diff --git a/include/uapi/linux/netfilter_ipv4/ipt_comp.h b/include/uapi/linux/netfilter_ipv4/ipt_comp.h new file mode 100644 index 0000000..37172fa --- /dev/null +++ b/include/uapi/linux/netfilter_ipv4/ipt_comp.h @@ -0,0 +1,18 @@ +#ifndef _IPT_COMP_H +#define _IPT_COMP_H + +#include + +struct ipt_comp { + __u32 spis[2]; /* Security Parameter Index */ + __u8 invflags; /* Inverse flags */ + __u8 hdrres; /* Test of the Reserved Filed */ +}; + + + +/* Values for "invflags" field in struct ipt_comp. */ +#define IPT_IPCOMP_INV_SPI 0x01 /* Invert the sense of spi. */ +#define IPT_IPCOMP_INV_MASK 0x01 /* All possible flags. */ + +#endif /*_IPT_COMP_H*/ diff --git a/net/ipv4/netfilter/Kconfig b/net/ipv4/netfilter/Kconfig index 40d5607..f71cf7b 100644 --- a/net/ipv4/netfilter/Kconfig +++ b/net/ipv4/netfilter/Kconfig @@ -81,6 +81,15 @@ config IP_NF_MATCH_AH To compile it as a module, choose M here. If unsure, say N. +config IP_NF_MATCH_IPCOMP + tristate '"ipcomp" match support' + depends on NETFILTER_ADVANCED + help + This match extension allows you to match a range of SPIs (Actually it's + Compression Parameter Index(CPI) inside IPComp header of IPSec packets. + + To compile it as a module, choose M here. If unsure, say N. + config IP_NF_MATCH_ECN tristate '"ecn" match support' depends on NETFILTER_ADVANCED diff --git a/net/ipv4/netfilter/Makefile b/net/ipv4/netfilter/Makefile index 19df72b..b67ecb8 100644 --- a/net/ipv4/netfilter/Makefile +++ b/net/ipv4/netfilter/Makefile @@ -45,6 +45,7 @@ obj-$(CONFIG_IP_NF_SECURITY) += iptable_security.o # matches obj-$(CONFIG_IP_NF_MATCH_AH) += ipt_ah.o +obj-$(CONFIG_IP_NF_MATCH_IPCOMP) += ipt_comp.o obj-$(CONFIG_IP_NF_MATCH_RPFILTER) += ipt_rpfilter.o # targets diff --git a/net/ipv4/netfilter/ipt_comp.c b/net/ipv4/netfilter/ipt_comp.c new file mode 100644 index 0000000..7796e6e --- /dev/null +++ b/net/ipv4/netfilter/ipt_comp.c @@ -0,0 +1,101 @@ +/* Kernel module to match IPComp parameters + * + * Copyright (C) 2013 WindRiver + * + * Author: + * Fan Du + * + * Based on: + * net/ipv4/netfilter/ipt_ah.c + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + */ + + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt +#include +#include +#include +#include + +#include +#include + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Fan Du "); +MODULE_DESCRIPTION("Xtables: IPv4 IPsec-IPComp SPI match"); + +/* Returns 1 if the spi is matched by the range, 0 otherwise */ +static inline bool +spi_match(u_int32_t min, u_int32_t max, u_int32_t spi, bool invert) +{ + bool r; + pr_debug("spi_match:%c 0x%x <= 0x%x <= 0x%x\n", + invert ? '!' : ' ', min, spi, max); + r = (spi >= min && spi <= max) ^ invert; + pr_debug(" result %s\n", r ? "PASS" : "FAILED"); + return r; +} + +static bool comp_mt(const struct sk_buff *skb, struct xt_action_param *par) +{ + struct ip_comp_hdr _comphdr; + const struct ip_comp_hdr *chdr; + const struct ipt_comp *compinfo = par->matchinfo; + + /* Must not be a fragment. */ + if (par->fragoff != 0) + return false; + + chdr = skb_header_pointer(skb, par->thoff, sizeof(_comphdr), &_comphdr); + if (chdr == NULL) { + /* We've been asked to examine this packet, and we + * can't. Hence, no choice but to drop. + */ + pr_debug("Dropping evil IPComp tinygram.\n"); + par->hotdrop = true; + return 0; + } + + return spi_match(compinfo->spis[0], compinfo->spis[1], + ntohl(chdr->cpi << 16), + !!(compinfo->invflags & IPT_IPCOMP_INV_SPI)); +} + +static int comp_mt_check(const struct xt_mtchk_param *par) +{ + const struct ipt_comp *compinfo = par->matchinfo; + + /* Must specify no unknown invflags */ + if (compinfo->invflags & ~IPT_IPCOMP_INV_MASK) { + pr_debug("unknown flags %X\n", compinfo->invflags); + return -EINVAL; + } + return 0; +} + +static struct xt_match comp_mt_reg __read_mostly = { + .name = "ipcomp", + .family = NFPROTO_IPV4, + .match = comp_mt, + .matchsize = sizeof(struct ipt_comp), + .proto = IPPROTO_COMP, + .checkentry = comp_mt_check, + .me = THIS_MODULE, +}; + +static int __init comp_mt_init(void) +{ + return xt_register_match(&comp_mt_reg); +} + +static void __exit comp_mt_exit(void) +{ + xt_unregister_match(&comp_mt_reg); +} + +module_init(comp_mt_init); +module_exit(comp_mt_exit);