From a58eaf210a223672f67c03d2070fa2fefdb2595b Mon Sep 17 00:00:00 2001 From: juhosg Date: Tue, 15 Apr 2008 06:11:23 +0000 Subject: update iptables to 1.4.0 (2.6 kernels only), refresh kernel patches git-svn-id: svn://svn.openwrt.org/openwrt/trunk@10843 3c298f89-4303-0410-b956-a3cf2f4a3e73 --- .../patches/170-netfilter_chaostables_0.8.patch | 853 +++++++++++++++++++++ 1 file changed, 853 insertions(+) create mode 100644 target/linux/generic-2.6/patches/170-netfilter_chaostables_0.8.patch (limited to 'target/linux/generic-2.6/patches/170-netfilter_chaostables_0.8.patch') diff --git a/target/linux/generic-2.6/patches/170-netfilter_chaostables_0.8.patch b/target/linux/generic-2.6/patches/170-netfilter_chaostables_0.8.patch new file mode 100644 index 000000000..063bcf1e6 --- /dev/null +++ b/target/linux/generic-2.6/patches/170-netfilter_chaostables_0.8.patch @@ -0,0 +1,853 @@ +Index: linux-2.6.21.7/include/linux/netfilter/oot_conntrack.h +=================================================================== +--- /dev/null ++++ linux-2.6.21.7/include/linux/netfilter/oot_conntrack.h +@@ -0,0 +1,5 @@ ++#if defined(CONFIG_IP_NF_CONNTRACK) || defined(CONFIG_IP_NF_CONNTRACK_MODULE) ++# include ++#else /* linux-2.6.20+ */ ++# include ++#endif +Index: linux-2.6.21.7/include/linux/netfilter/oot_trans.h +=================================================================== +--- /dev/null ++++ linux-2.6.21.7/include/linux/netfilter/oot_trans.h +@@ -0,0 +1,14 @@ ++/* Out of tree workarounds */ ++#include ++#if LINUX_VERSION_CODE <= KERNEL_VERSION(2, 6, 18) ++# define HAVE_MATCHINFOSIZE 1 ++# define HAVE_TARGUSERINFO 1 ++# define HAVE_TARGINFOSIZE 1 ++#endif ++#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 20) ++# define nfmark mark ++#endif ++#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 21) ++# define tcp_v4_check(tcph, tcph_sz, s, d, csp) \ ++ tcp_v4_check((tcph_sz), (s), (d), (csp)) ++#endif +Index: linux-2.6.21.7/include/linux/netfilter/xt_CHAOS.h +=================================================================== +--- /dev/null ++++ linux-2.6.21.7/include/linux/netfilter/xt_CHAOS.h +@@ -0,0 +1,14 @@ ++#ifndef _LINUX_NETFILTER_XT_CHAOS_H ++#define _LINUX_NETFILTER_XT_CHAOS_H 1 ++ ++enum xt_chaos_target_variant { ++ XTCHAOS_NORMAL, ++ XTCHAOS_TARPIT, ++ XTCHAOS_DELUDE, ++}; ++ ++struct xt_chaos_target_info { ++ uint8_t variant; ++}; ++ ++#endif /* _LINUX_NETFILTER_XT_CHAOS_H */ +Index: linux-2.6.21.7/include/linux/netfilter/xt_portscan.h +=================================================================== +--- /dev/null ++++ linux-2.6.21.7/include/linux/netfilter/xt_portscan.h +@@ -0,0 +1,8 @@ ++#ifndef _LINUX_NETFILTER_XT_PORTSCAN_H ++#define _LINUX_NETFILTER_XT_PORTSCAN_H 1 ++ ++struct xt_portscan_match_info { ++ uint8_t match_stealth, match_syn, match_cn, match_gr; ++}; ++ ++#endif /* _LINUX_NETFILTER_XT_PORTSCAN_H */ +Index: linux-2.6.21.7/net/netfilter/find_match.c +=================================================================== +--- /dev/null ++++ linux-2.6.21.7/net/netfilter/find_match.c +@@ -0,0 +1,39 @@ ++/* ++ xt_request_find_match ++ by Jan Engelhardt , 2006 - 2007 ++ ++ Based upon linux-2.6.18.5/net/netfilter/x_tables.c: ++ Copyright (C) 2006-2006 Harald Welte ++ This program is free software; you can redistribute it and/or modify ++ it under the terms of the GNU General Public License version 2 as ++ published by the Free Software Foundation. ++*/ ++#include ++#include ++#include ++#include ++ ++/* ++ * Yeah this code is sub-optimal, but the function is missing in ++ * mainline so far. -jengelh ++ */ ++static struct xt_match *xt_request_find_match_lo(int af, const char *name, ++ u8 revision) ++{ ++ static const char *const xt_prefix[] = { ++ [AF_INET] = "ip", ++ [AF_INET6] = "ip6", ++ [NF_ARP] = "arp", ++ }; ++ struct xt_match *match; ++ ++ match = try_then_request_module(xt_find_match(af, name, revision), ++ "%st_%s", xt_prefix[af], name); ++ if (IS_ERR(match) || match == NULL) ++ return NULL; ++ ++ return match; ++} ++ ++/* In case it goes into mainline, let this out-of-tree package compile */ ++#define xt_request_find_match xt_request_find_match_lo +Index: linux-2.6.21.7/net/netfilter/Kconfig +=================================================================== +--- linux-2.6.21.7.orig/net/netfilter/Kconfig ++++ linux-2.6.21.7/net/netfilter/Kconfig +@@ -287,6 +287,14 @@ config NETFILTER_XTABLES + + # alphabetically ordered list of targets + ++config NETFILTER_XT_TARGET_CHAOS ++ tristate '"CHAOS" target support' ++ depends on NETFILTER_XTABLES ++ help ++ This option adds a `CHAOS' target. ++ ++ To compile it as a module, choose M here. If unsure, say N. ++ + config NETFILTER_XT_TARGET_CLASSIFY + tristate '"CLASSIFY" target support' + depends on NETFILTER_XTABLES +@@ -315,6 +323,14 @@ config NETFILTER_XT_TARGET_CONNMARK + . The module will be called + ipt_CONNMARK.o. If unsure, say `N'. + ++config NETFILTER_XT_TARGET_DELUDE ++ tristate '"DELUDE" target support' ++ depends on NETFILTER_XTABLES ++ help ++ This option adds a `DELUDE' target. ++ ++ To compile it as a module, choose M here. If unsure, say N. ++ + config NETFILTER_XT_TARGET_DSCP + tristate '"DSCP" target support' + depends on NETFILTER_XTABLES +@@ -563,6 +579,14 @@ config NETFILTER_XT_MATCH_POLICY + + To compile it as a module, choose M here. If unsure, say N. + ++config NETFILTER_XT_MATCH_PORTSCAN ++ tristate '"portscan" match support' ++ depends on NETFILTER_XTABLES ++ help ++ This option adds a 'portscan' match support. ++ ++ To compile it as a module, choose M here. If unsure, say N. ++ + config NETFILTER_XT_MATCH_MULTIPORT + tristate "Multiple port match support" + depends on NETFILTER_XTABLES +Index: linux-2.6.21.7/net/netfilter/Makefile +=================================================================== +--- linux-2.6.21.7.orig/net/netfilter/Makefile ++++ linux-2.6.21.7/net/netfilter/Makefile +@@ -47,6 +47,8 @@ obj-$(CONFIG_NETFILTER_XT_TARGET_NOTRACK + obj-$(CONFIG_NETFILTER_XT_TARGET_SECMARK) += xt_SECMARK.o + obj-$(CONFIG_NETFILTER_XT_TARGET_TCPMSS) += xt_TCPMSS.o + obj-$(CONFIG_NETFILTER_XT_TARGET_CONNSECMARK) += xt_CONNSECMARK.o ++obj-$(CONFIG_NETFILTER_XT_TARGET_CHAOS) += xt_CHAOS.o ++obj-$(CONFIG_NETFILTER_XT_TARGET_DELUDE) += xt_DELUDE.o + + # matches + obj-$(CONFIG_NETFILTER_XT_MATCH_COMMENT) += xt_comment.o +@@ -74,3 +76,4 @@ obj-$(CONFIG_NETFILTER_XT_MATCH_STRING) + obj-$(CONFIG_NETFILTER_XT_MATCH_TCPMSS) += xt_tcpmss.o + obj-$(CONFIG_NETFILTER_XT_MATCH_PHYSDEV) += xt_physdev.o + obj-$(CONFIG_NETFILTER_XT_MATCH_HASHLIMIT) += xt_hashlimit.o ++obj-$(CONFIG_NETFILTER_XT_MATCH_PORTSCAN) += xt_portscan.o +Index: linux-2.6.21.7/net/netfilter/xt_CHAOS.c +=================================================================== +--- /dev/null ++++ linux-2.6.21.7/net/netfilter/xt_CHAOS.c +@@ -0,0 +1,200 @@ ++/* ++ * CHAOS target for netfilter ++ * Copyright © CC Computer Consultants GmbH, 2006 - 2007 ++ * Contact: Jan Engelhardt ++ * ++ * This program is free software; you can redistribute it and/or modify ++ * it under the terms of the GNU General Public License; either version ++ * 2 or 3 as published by the Free Software Foundation. ++ */ ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#if defined(_LOCAL) ++# include "xt_CHAOS.h" ++# include "find_match.c" ++#elif defined(CONFIG_NETFILTER_XT_TARGET_CHAOS) || \ ++ defined(CONFIG_NETFILTER_XT_TARGET_CHAOS_MODULE) ++# include ++# include "find_match.c" ++#else ++# include "xt_CHAOS.h" ++# include "find_match.c" ++#endif ++#define PFX KBUILD_MODNAME ": " ++ ++/* Module parameters */ ++static unsigned int reject_percentage = ~0U * .01; ++static unsigned int delude_percentage = ~0U * .0101; ++module_param(reject_percentage, uint, S_IRUGO | S_IWUSR); ++module_param(delude_percentage, uint, S_IRUGO | S_IWUSR); ++ ++/* References to other matches/targets */ ++static struct xt_match *xm_tcp; ++static struct xt_target *xt_delude, *xt_reject, *xt_tarpit; ++ ++static int have_delude, have_tarpit; ++ ++/* Static data for other matches/targets */ ++static const struct ipt_reject_info reject_params = { ++ .with = ICMP_HOST_UNREACH, ++}; ++ ++static const struct xt_tcp tcp_params = { ++ .spts = {0, ~0}, ++ .dpts = {0, ~0}, ++}; ++ ++/* CHAOS functions */ ++static void xt_chaos_total(const struct xt_chaos_target_info *info, ++ struct sk_buff **pskb, const struct net_device *in, ++ const struct net_device *out, unsigned int hooknum) ++{ ++ const struct iphdr *iph = ip_hdr(*pskb); ++ const int protoff = 4 * iph->ihl; ++ const int offset = ntohs(iph->frag_off) & IP_OFFSET; ++ const struct xt_target *destiny; ++ int hotdrop = 0, ret; ++ ++ ret = xm_tcp->match(*pskb, in, out, xm_tcp, &tcp_params, ++ offset, protoff, &hotdrop); ++ if (!ret || hotdrop || (unsigned int)net_random() > delude_percentage) ++ return; ++ ++ destiny = (info->variant == XTCHAOS_TARPIT) ? xt_tarpit : xt_delude; ++ destiny->target(pskb, in, out, hooknum, destiny, NULL); ++ return; ++} ++ ++static unsigned int chaos_tg(struct sk_buff **pskb, ++ const struct net_device *in, const struct net_device *out, ++ unsigned int hooknum, const struct xt_target *target, const void *targinfo) ++{ ++ /* ++ * Equivalent to: ++ * -A chaos -m statistic --mode random --probability \ ++ * $reject_percentage -j REJECT --reject-with host-unreach; ++ * -A chaos -p tcp -m statistic --mode random --probability \ ++ * $delude_percentage -j DELUDE; ++ * -A chaos -j DROP; ++ */ ++ const struct xt_chaos_target_info *info = targinfo; ++ const struct iphdr *iph = ip_hdr(*pskb); ++ ++ if ((unsigned int)net_random() <= reject_percentage) ++ return xt_reject->target(pskb, in, out, hooknum, target, ++ &reject_params); ++ ++ /* TARPIT/DELUDE may not be called from the OUTPUT chain */ ++ if (iph->protocol == IPPROTO_TCP && ++ info->variant != XTCHAOS_NORMAL && hooknum != NF_IP_LOCAL_OUT) ++ xt_chaos_total(info, pskb, in, out, hooknum); ++ ++ return NF_DROP; ++} ++ ++static int chaos_tg_check(const char *tablename, const void *entry, ++ const struct xt_target *target, void *targinfo, unsigned int hook_mask) ++{ ++ const struct xt_chaos_target_info *info = targinfo; ++ ++ if (info->variant == XTCHAOS_DELUDE && !have_delude) { ++ printk(KERN_WARNING PFX "Error: Cannot use --delude when " ++ "DELUDE module not available\n"); ++ return false; ++ } ++ if (info->variant == XTCHAOS_TARPIT && !have_tarpit) { ++ printk(KERN_WARNING PFX "Error: Cannot use --tarpit when " ++ "TARPIT module not available\n"); ++ return false; ++ } ++ ++ return true; ++} ++ ++static struct xt_target chaos_tg_reg = { ++ .name = "CHAOS", ++ .family = AF_INET, ++ .table = "filter", ++ .hooks = (1 << NF_IP_LOCAL_IN) | (1 << NF_IP_FORWARD) | ++ (1 << NF_IP_LOCAL_OUT), ++ .checkentry = chaos_tg_check, ++ .target = chaos_tg, ++ .targetsize = sizeof(struct xt_chaos_target_info), ++ .me = THIS_MODULE, ++}; ++ ++static int __init chaos_tg_init(void) ++{ ++ int ret = -EINVAL; ++ ++ xm_tcp = xt_request_find_match(AF_INET, "tcp", 0); ++ if (xm_tcp == NULL) { ++ printk(KERN_WARNING PFX "Error: Could not find or load " ++ "\"tcp\" match\n"); ++ return -EINVAL; ++ } ++ ++ xt_reject = xt_request_find_target(AF_INET, "REJECT", 0); ++ if (xt_reject == NULL) { ++ printk(KERN_WARNING PFX "Error: Could not find or load " ++ "\"REJECT\" target\n"); ++ goto out2; ++ } ++ ++ xt_tarpit = xt_request_find_target(AF_INET, "TARPIT", 0); ++ have_tarpit = xt_tarpit != NULL; ++ if (!have_tarpit) ++ printk(KERN_WARNING PFX "Warning: Could not find or load " ++ "\"TARPIT\" target\n"); ++ ++ xt_delude = xt_request_find_target(AF_INET, "DELUDE", 0); ++ have_delude = xt_delude != NULL; ++ if (!have_delude) ++ printk(KERN_WARNING PFX "Warning: Could not find or load " ++ "\"DELUDE\" target\n"); ++ ++ if ((ret = xt_register_target(&chaos_tg_reg)) != 0) { ++ printk(KERN_WARNING PFX "xt_register_target returned " ++ "error %d\n", ret); ++ goto out3; ++ } ++ ++ return 0; ++ ++ out3: ++ if (have_delude) ++ module_put(xt_delude->me); ++ if (have_tarpit) ++ module_put(xt_tarpit->me); ++ module_put(xt_reject->me); ++ out2: ++ module_put(xm_tcp->me); ++ return ret; ++} ++ ++static void __exit chaos_tg_exit(void) ++{ ++ xt_unregister_target(&chaos_tg_reg); ++ module_put(xm_tcp->me); ++ module_put(xt_reject->me); ++ if (have_delude) ++ module_put(xt_delude->me); ++ if (have_tarpit) ++ module_put(xt_tarpit->me); ++ return; ++} ++ ++module_init(chaos_tg_init); ++module_exit(chaos_tg_exit); ++MODULE_AUTHOR("Jan Engelhardt "); ++MODULE_DESCRIPTION("netfilter \"CHAOS\" target"); ++MODULE_LICENSE("GPL"); ++MODULE_ALIAS("ipt_CHAOS"); +Index: linux-2.6.21.7/net/netfilter/xt_DELUDE.c +=================================================================== +--- /dev/null ++++ linux-2.6.21.7/net/netfilter/xt_DELUDE.c +@@ -0,0 +1,197 @@ ++/* ++ * DELUDE target ++ * Copyright © CC Computer Consultants GmbH, 2007 ++ * Contact: Jan Engelhardt ++ * ++ * Based upon linux-2.6.18.5/net/ipv4/netfilter/ipt_REJECT.c: ++ * (C) 1999-2001 Paul `Rusty' Russell ++ * (C) 2002-2004 Netfilter Core Team ++ * ++ * xt_DELUDE acts like REJECT, but does reply with SYN-ACK on SYN. ++ * ++ * This program is free software; you can redistribute it and/or modify ++ * it under the terms of the GNU General Public License version 2 as ++ * published by the Free Software Foundation. ++ */ ++#include ++#include ++#include ++#include ++#include ++#ifdef CONFIG_BRIDGE_NETFILTER ++# include ++#endif ++#include ++#define PFX KBUILD_MODNAME ": " ++ ++static void delude_send_reset(struct sk_buff *oldskb, unsigned int hook) ++{ ++ struct tcphdr _otcph, *oth, *tcph; ++ unsigned int addr_type; ++ struct sk_buff *nskb; ++ u_int16_t tmp_port; ++ u_int32_t tmp_addr; ++ struct iphdr *niph; ++ bool needs_ack; ++ ++ /* IP header checks: fragment. */ ++ if (ip_hdr(oldskb)->frag_off & htons(IP_OFFSET)) ++ return; ++ ++ oth = skb_header_pointer(oldskb, ip_hdrlen(oldskb), ++ sizeof(_otcph), &_otcph); ++ if (oth == NULL) ++ return; ++ ++ /* No RST for RST. */ ++ if (oth->rst) ++ return; ++ ++ /* Check checksum */ ++ if (nf_ip_checksum(oldskb, hook, ip_hdrlen(oldskb), IPPROTO_TCP)) ++ return; ++ ++ /* We need a linear, writeable skb. We also need to expand ++ headroom in case hh_len of incoming interface < hh_len of ++ outgoing interface */ ++ nskb = skb_copy_expand(oldskb, LL_MAX_HEADER, skb_tailroom(oldskb), ++ GFP_ATOMIC); ++ if (!nskb) ++ return; ++ ++ /* This packet will not be the same as the other: clear nf fields */ ++ nf_reset(nskb); ++ nskb->mark = 0; ++ skb_init_secmark(nskb); ++ ++ skb_shinfo(nskb)->gso_size = 0; ++ skb_shinfo(nskb)->gso_segs = 0; ++ skb_shinfo(nskb)->gso_type = 0; ++ ++ tcph = (struct tcphdr *)(skb_network_header(nskb) + ip_hdrlen(nskb)); ++ ++ /* Swap source and dest */ ++ niph = ip_hdr(nskb); ++ tmp_addr = niph->saddr; ++ niph->saddr = niph->daddr; ++ niph->daddr = tmp_addr; ++ tmp_port = tcph->source; ++ tcph->source = tcph->dest; ++ tcph->dest = tmp_port; ++ ++ /* Truncate to length (no data) */ ++ tcph->doff = sizeof(struct tcphdr) / 4; ++ skb_trim(nskb, ip_hdrlen(nskb) + sizeof(struct tcphdr)); ++ niph->tot_len = htons(nskb->len); ++ ++ if (oth->syn && !oth->ack && !oth->rst && !oth->fin) { ++ /* DELUDE essential part */ ++ tcph->ack_seq = htonl(ntohl(oth->seq) + oth->syn + oth->fin + ++ oldskb->len - ip_hdrlen(oldskb) - ++ (oth->doff << 2)); ++ tcph->seq = false; ++ tcph->ack = true; ++ } else { ++ if (!tcph->ack) { ++ needs_ack = true; ++ tcph->ack_seq = htonl(ntohl(oth->seq) + oth->syn + ++ oth->fin + oldskb->len - ++ ip_hdrlen(oldskb) - (oth->doff<<2)); ++ tcph->seq = false; ++ } else { ++ needs_ack = false; ++ tcph->seq = oth->ack_seq; ++ tcph->ack_seq = false; ++ } ++ ++ /* Reset flags */ ++ ((u_int8_t *)tcph)[13] = 0; ++ tcph->rst = true; ++ tcph->ack = needs_ack; ++ } ++ ++ tcph->window = 0; ++ tcph->urg_ptr = 0; ++ ++ /* Adjust TCP checksum */ ++ tcph->check = 0; ++ tcph->check = tcp_v4_check(sizeof(struct tcphdr), niph->saddr, ++ niph->daddr, csum_partial((char *)tcph, ++ sizeof(struct tcphdr), 0)); ++ ++ /* Set DF, id = 0 */ ++ niph->frag_off = htons(IP_DF); ++ niph->id = 0; ++ ++ addr_type = RTN_UNSPEC; ++#ifdef CONFIG_BRIDGE_NETFILTER ++ if (hook != NF_IP_FORWARD || (nskb->nf_bridge != NULL && ++ nskb->nf_bridge->mask & BRNF_BRIDGED)) ++#else ++ if (hook != NF_IP_FORWARD) ++#endif ++ addr_type = RTN_LOCAL; ++ ++ if (ip_route_me_harder(&nskb, addr_type)) ++ goto free_nskb; ++ ++ nskb->ip_summed = CHECKSUM_NONE; ++ ++ /* Adjust IP TTL */ ++ niph->ttl = dst_metric(nskb->dst, RTAX_HOPLIMIT); ++ ++ /* Adjust IP checksum */ ++ niph->check = 0; ++ niph->check = ip_fast_csum(skb_network_header(nskb), niph->ihl); ++ ++ /* "Never happens" */ ++ if (nskb->len > dst_mtu(nskb->dst)) ++ goto free_nskb; ++ ++ nf_ct_attach(nskb, oldskb); ++ ++ NF_HOOK(PF_INET, NF_IP_LOCAL_OUT, nskb, NULL, nskb->dst->dev, ++ dst_output); ++ return; ++ ++ free_nskb: ++ kfree_skb(nskb); ++} ++ ++static unsigned int delude_tg(struct sk_buff **pskb, ++ const struct net_device *in, const struct net_device *out, ++ unsigned int hooknum, const struct xt_target *target, const void *targinfo) ++{ ++ /* WARNING: This code causes reentry within iptables. ++ This means that the iptables jump stack is now crap. We ++ must return an absolute verdict. --RR */ ++ delude_send_reset(*pskb, hooknum); ++ return NF_DROP; ++} ++ ++static struct xt_target delude_tg_reg = { ++ .name = "DELUDE", ++ .family = AF_INET, ++ .table = "filter", ++ .hooks = (1 << NF_IP_LOCAL_IN) | (1 << NF_IP_FORWARD), ++ .target = delude_tg, ++ .proto = IPPROTO_TCP, ++ .me = THIS_MODULE, ++}; ++ ++static int __init delude_tg_init(void) ++{ ++ return xt_register_target(&delude_tg_reg); ++} ++ ++static void __exit delude_tg_exit(void) ++{ ++ xt_unregister_target(&delude_tg_reg); ++} ++ ++module_init(delude_tg_init); ++module_exit(delude_tg_exit); ++MODULE_AUTHOR("Jan Engelhardt "); ++MODULE_DESCRIPTION("netfilter \"DELUDE\" target"); ++MODULE_LICENSE("GPL"); ++MODULE_ALIAS("ipt_DELUDE"); +Index: linux-2.6.21.7/net/netfilter/xt_portscan.c +=================================================================== +--- /dev/null ++++ linux-2.6.21.7/net/netfilter/xt_portscan.c +@@ -0,0 +1,269 @@ ++/* ++ * portscan match for netfilter ++ * Copyright © CC Computer Consultants GmbH, 2006 - 2007 ++ * Contact: Jan Engelhardt ++ * ++ * This program is free software; you can redistribute it and/or modify ++ * it under the terms of the GNU General Public License; either version ++ * 2 or 3 as published by the Free Software Foundation. ++ */ ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++#if defined(_LOCAL) ++# include "xt_portscan.h" ++#elif defined(CONFIG_NETFILTER_XT_MATCH_PORTSCAN) || \ ++ defined(CONFIG_NETFILTER_XT_MATCH_PORTSCAN_MODULE) ++# include ++#else ++# include "xt_portscan.h" ++#endif ++#define PFX KBUILD_MODNAME ": " ++ ++enum { ++ TCP_FLAGS_ALL3 = TCP_FLAG_FIN | TCP_FLAG_RST | TCP_FLAG_SYN, ++ TCP_FLAGS_ALL4 = TCP_FLAGS_ALL3 | TCP_FLAG_ACK, ++ TCP_FLAGS_ALL6 = TCP_FLAGS_ALL4 | TCP_FLAG_PSH | TCP_FLAG_URG, ++}; ++ ++/* Module parameters */ ++static unsigned int ++ connmark_mask = ~0, ++ packet_mask = ~0, ++ mark_seen = 0x9, ++ mark_synrcv = 0x1, ++ mark_closed = 0x2, ++ mark_synscan = 0x3, ++ mark_estab1 = 0x4, ++ mark_estab2 = 0x5, ++ mark_cnscan = 0x6, ++ mark_grscan = 0x7, ++ mark_valid = 0x8; ++ ++module_param(connmark_mask, uint, S_IRUGO | S_IWUSR); ++module_param(packet_mask, uint, S_IRUGO | S_IWUSR); ++module_param(mark_seen, uint, S_IRUGO | S_IWUSR); ++module_param(mark_synrcv, uint, S_IRUGO | S_IWUSR); ++module_param(mark_closed, uint, S_IRUGO | S_IWUSR); ++module_param(mark_synscan, uint, S_IRUGO | S_IWUSR); ++module_param(mark_estab1, uint, S_IRUGO | S_IWUSR); ++module_param(mark_estab2, uint, S_IRUGO | S_IWUSR); ++module_param(mark_cnscan, uint, S_IRUGO | S_IWUSR); ++module_param(mark_grscan, uint, S_IRUGO | S_IWUSR); ++module_param(mark_valid, uint, S_IRUGO | S_IWUSR); ++MODULE_PARM_DESC(connmark_mask, "only set specified bits in connection mark"); ++MODULE_PARM_DESC(packet_mask, "only set specified bits in packet mark"); ++MODULE_PARM_DESC(mark_seen, "nfmark value for packet-seen state"); ++MODULE_PARM_DESC(mark_synrcv, "connmark value for SYN Received state"); ++MODULE_PARM_DESC(mark_closed, "connmark value for closed state"); ++MODULE_PARM_DESC(mark_synscan, "connmark value for SYN Scan state"); ++MODULE_PARM_DESC(mark_estab1, "connmark value for Established-1 state"); ++MODULE_PARM_DESC(mark_estab2, "connmark value for Established-2 state"); ++MODULE_PARM_DESC(mark_cnscan, "connmark value for Connect Scan state"); ++MODULE_PARM_DESC(mark_grscan, "connmark value for Grab Scan state"); ++MODULE_PARM_DESC(mark_valid, "connmark value for Valid state"); ++ ++/* TCP flag functions */ ++static inline bool tflg_ack4(const struct tcphdr *th) ++{ ++ return (tcp_flag_word(th) & TCP_FLAGS_ALL4) == TCP_FLAG_ACK; ++} ++ ++static inline bool tflg_ack6(const struct tcphdr *th) ++{ ++ return (tcp_flag_word(th) & TCP_FLAGS_ALL6) == TCP_FLAG_ACK; ++} ++ ++static inline bool tflg_fin(const struct tcphdr *th) ++{ ++ return (tcp_flag_word(th) & TCP_FLAGS_ALL3) == TCP_FLAG_FIN; ++} ++ ++static inline bool tflg_rst(const struct tcphdr *th) ++{ ++ return (tcp_flag_word(th) & TCP_FLAGS_ALL3) == TCP_FLAG_RST; ++} ++ ++static inline bool tflg_rstack(const struct tcphdr *th) ++{ ++ return (tcp_flag_word(th) & TCP_FLAGS_ALL4) == ++ (TCP_FLAG_ACK | TCP_FLAG_RST); ++} ++ ++static inline bool tflg_syn(const struct tcphdr *th) ++{ ++ return (tcp_flag_word(th) & TCP_FLAGS_ALL4) == TCP_FLAG_SYN; ++} ++ ++static inline bool tflg_synack(const struct tcphdr *th) ++{ ++ return (tcp_flag_word(th) & TCP_FLAGS_ALL4) == ++ (TCP_FLAG_SYN | TCP_FLAG_ACK); ++} ++ ++/* portscan functions */ ++static inline bool portscan_mt_stealth(const struct tcphdr *th) ++{ ++ /* ++ * "Connection refused" replies to our own probes must not be matched. ++ */ ++ if (tflg_rstack(th)) ++ return false; ++ ++ if (tflg_rst(th) && printk_ratelimit()) { ++ printk(KERN_WARNING PFX "Warning: Pure RST received\n"); ++ return false; ++ } ++ ++ /* ++ * -p tcp ! --syn -m conntrack --ctstate INVALID: Looking for non-start ++ * packets that are not associated with any connection -- this will ++ * match most scan types (NULL, XMAS, FIN) and ridiculous flag ++ * combinations (SYN-RST, SYN-FIN, SYN-FIN-RST, FIN-RST, etc.). ++ */ ++ return !tflg_syn(th); ++} ++ ++static inline unsigned int portscan_mt_full(int mark, ++ enum ip_conntrack_info ctstate, bool loopback, const struct tcphdr *tcph, ++ unsigned int payload_len) ++{ ++ if (mark == mark_estab2) { ++ /* ++ * -m connmark --mark $ESTAB2 ++ */ ++ if (tflg_ack4(tcph) && payload_len == 0) ++ return mark; /* keep mark */ ++ else if (tflg_rst(tcph) || tflg_fin(tcph)) ++ return mark_grscan; ++ else ++ return mark_valid; ++ } else if (mark == mark_estab1) { ++ /* ++ * -m connmark --mark $ESTAB1 ++ */ ++ if (tflg_rst(tcph) || tflg_fin(tcph)) ++ return mark_cnscan; ++ else if (!loopback && tflg_ack4(tcph) && payload_len == 0) ++ return mark_estab2; ++ else ++ return mark_valid; ++ } else if (mark == mark_synrcv) { ++ /* ++ * -m connmark --mark $SYN ++ */ ++ if (loopback && tflg_synack(tcph)) ++ return mark; /* keep mark */ ++ else if (loopback && tflg_rstack(tcph)) ++ return mark_closed; ++ else if (tflg_ack6(tcph)) ++ return mark_estab1; ++ else ++ return mark_synscan; ++ } else if (ctstate == IP_CT_NEW && tflg_syn(tcph)) { ++ /* ++ * -p tcp --syn --ctstate NEW ++ */ ++ return mark_synrcv; ++ } ++ return mark; ++} ++ ++static int portscan_mt(const struct sk_buff *skb, ++ const struct net_device *in, const struct net_device *out, ++ const struct xt_match *match, const void *matchinfo, int offset, ++ unsigned int protoff, int *hotdrop) ++{ ++ const struct xt_portscan_match_info *info = matchinfo; ++ enum ip_conntrack_info ctstate; ++ const struct tcphdr *tcph; ++ struct nf_conn *ctdata; ++ struct tcphdr tcph_buf; ++ ++ tcph = skb_header_pointer(skb, protoff, sizeof(tcph_buf), &tcph_buf); ++ if (tcph == NULL) ++ return false; ++ ++ /* Check for invalid packets: -m conntrack --ctstate INVALID */ ++ if ((ctdata = nf_ct_get(skb, &ctstate)) == NULL) { ++ if (info->match_stealth) ++ return portscan_mt_stealth(tcph); ++ /* ++ * If @ctdata is NULL, we cannot match the other scan ++ * types, return. ++ */ ++ return false; ++ } ++ ++ /* ++ * If -m portscan was previously applied to this packet, the rules we ++ * simulate must not be run through again. And for speedup, do not call ++ * it either when the connection is already VALID. ++ */ ++ if ((ctdata->mark & connmark_mask) == mark_valid || ++ (skb->mark & packet_mask) != mark_seen) { ++ unsigned int n; ++ ++ n = portscan_mt_full(ctdata->mark & connmark_mask, ctstate, ++ in == &loopback_dev, tcph, ++ skb->len - protoff - 4 * tcph->doff); ++ ++ ctdata->mark = (ctdata->mark & ~connmark_mask) | n; ++ ((struct sk_buff *)skb)->mark = ++ (skb->mark & ~packet_mask) ^ mark_seen; ++ } ++ ++ return (info->match_syn && ctdata->mark == mark_synscan) || ++ (info->match_cn && ctdata->mark == mark_cnscan) || ++ (info->match_gr && ctdata->mark == mark_grscan); ++} ++ ++static int portscan_mt_check(const char *tablename, const void *entry, ++ const struct xt_match *match, void *matchinfo, unsigned int hook_mask) ++{ ++ const struct xt_portscan_match_info *info = matchinfo; ++ ++ if ((info->match_stealth & ~1) || (info->match_syn & ~1) || ++ (info->match_cn & ~1) || (info->match_gr & ~1)) { ++ printk(KERN_WARNING PFX "Invalid flags\n"); ++ return false; ++ } ++ return true; ++} ++ ++static struct xt_match portscan_mt_reg __read_mostly = { ++ .name = "portscan", ++ .family = AF_INET, ++ .match = portscan_mt, ++ .checkentry = portscan_mt_check, ++ .matchsize = sizeof(struct xt_portscan_match_info), ++ .proto = IPPROTO_TCP, ++ .me = THIS_MODULE, ++}; ++ ++static int __init portscan_mt_init(void) ++{ ++ return xt_register_match(&portscan_mt_reg); ++} ++ ++static void __exit portscan_mt_exit(void) ++{ ++ xt_unregister_match(&portscan_mt_reg); ++ return; ++} ++ ++module_init(portscan_mt_init); ++module_exit(portscan_mt_exit); ++MODULE_AUTHOR("Jan Engelhardt "); ++MODULE_DESCRIPTION("netfilter \"portscan\" match"); ++MODULE_LICENSE("GPL"); ++MODULE_ALIAS("ipt_portscan"); -- cgit v1.2.3