target/linux/generic-2.6/patches/170-netfilter_chaostables.patch

   1 diff -ruN linux-2.6.19.1.orig/include/linux/netfilter/xt_CHAOS.h linux-2.6.19.1/include/linux/netfilter/xt_CHAOS.h
   2 --- linux-2.6.19.1.orig/include/linux/netfilter/xt_CHAOS.h      1970-01-01 01:00:00.000000000 +0100
   3 +++ linux-2.6.19.1/include/linux/netfilter/xt_CHAOS.h   2007-01-11 13:28:07.656144799 +0100
   4 @@ -0,0 +1,14 @@
   5 +#ifndef _LINUX_XT_CHAOS_H
   6 +#define _LINUX_XT_CHAOS_H 1
   7 +
   8 +enum xt_chaos_variant {
   9 +       XTCHAOS_NORMAL,
  10 +       XTCHAOS_TARPIT,
  11 +       XTCHAOS_DELUDE,
  12 +};
  13 +
  14 +struct xt_chaos_info {
  15 +       enum xt_chaos_variant variant;
  16 +};
  17 +
  18 +#endif /* _LINUX_XT_CHAOS_H */
  19 diff -ruN linux-2.6.19.1.orig/include/linux/netfilter/xt_portscan.h linux-2.6.19.1/include/linux/netfilter/xt_portscan.h
  20 --- linux-2.6.19.1.orig/include/linux/netfilter/xt_portscan.h   1970-01-01 01:00:00.000000000 +0100
  21 +++ linux-2.6.19.1/include/linux/netfilter/xt_portscan.h        2007-01-11 13:28:07.656144799 +0100
  22 @@ -0,0 +1,8 @@
  23 +#ifndef _LINUX_XT_PORTSCAN_H
  24 +#define _LINUX_XT_PORTSCAN_H 1
  25 +
  26 +struct xt_portscan_info {
  27 +       unsigned int match_stealth, match_syn, match_cn, match_gr;
  28 +};
  29 +
  30 +#endif /* _LINUX_XT_PORTSCAN_H */
  31 diff -ruN linux-2.6.19.1.orig/net/netfilter/find_match.c linux-2.6.19.1/net/netfilter/find_match.c
  32 --- linux-2.6.19.1.orig/net/netfilter/find_match.c      1970-01-01 01:00:00.000000000 +0100
  33 +++ linux-2.6.19.1/net/netfilter/find_match.c   2007-01-11 13:28:12.191994379 +0100
  34 @@ -0,0 +1,37 @@
  35 +/*
  36 +    xt_request_find_match
  37 +    by Jan Engelhardt <jengelh [at] gmx de>, 2006 - 2007
  38 +
  39 +    Based upon linux-2.6.18.5/net/netfilter/x_tables.c:
  40 +    Copyright (C) 2006-2006 Harald Welte <laforge@netfilter.org>
  41 +    This program is free software; you can redistribute it and/or modify
  42 +    it under the terms of the GNU General Public License version 2 as
  43 +    published by the Free Software Foundation.
  44 +*/
  45 +
  46 +#include <linux/err.h>
  47 +#include <linux/netfilter_arp.h>
  48 +#include <linux/socket.h>
  49 +#include <linux/netfilter/x_tables.h>
  50 +
  51 +/*
  52 + * Yeah this code is sub-optimal, but the function is missing in
  53 + * mainline so far. -jengelh
  54 + */
  55 +static struct xt_match *xt_request_find_match(int af, const char *name,
  56 +    u8 revision)
  57 +{
  58 +       static const char *const xt_prefix[] = {
  59 +               [AF_INET]  = "ip",
  60 +               [AF_INET6] = "ip6",
  61 +               [NF_ARP]   = "arp",
  62 +       };
  63 +       struct xt_match *match;
  64 +
  65 +       match = try_then_request_module(xt_find_match(af, name, revision),
  66 +               "%st_%s", xt_prefix[af], name);
  67 +       if(IS_ERR(match) || match == NULL)
  68 +               return NULL;
  69 +
  70 +       return match;
  71 +}
  72 diff -ruN linux-2.6.19.1.orig/net/netfilter/Kconfig linux-2.6.19.1/net/netfilter/Kconfig
  73 --- linux-2.6.19.1.orig/net/netfilter/Kconfig   2007-01-11 13:27:24.445577700 +0100
  74 +++ linux-2.6.19.1/net/netfilter/Kconfig        2007-01-11 13:28:09.092097179 +0100
  75 @@ -122,6 +122,14 @@
  76
  77  # alphabetically ordered list of targets
  78
  79 +config NETFILTER_XT_TARGET_CHAOS
  80 +       tristate '"CHAOS" target support'
  81 +       depends on NETFILTER_XTABLES
  82 +       help
  83 +         This option adds a `CHAOS' target.
  84 +
  85 +         To compile it as a module, choose M here.  If unsure, say N.
  86 +
  87  config NETFILTER_XT_TARGET_CLASSIFY
  88         tristate '"CLASSIFY" target support'
  89         depends on NETFILTER_XTABLES
  90 @@ -148,6 +156,14 @@
  91           <file:Documentation/modules.txt>.  The module will be called
  92           ipt_CONNMARK.o.  If unsure, say `N'.
  93
  94 +config NETFILTER_XT_TARGET_DELUDE
  95 +       tristate '"DELUDE" target support'
  96 +       depends on NETFILTER_XTABLES
  97 +       help
  98 +         This option adds a `DELUDE' target.
  99 +
 100 +         To compile it as a module, choose M here.  If unsure, say N.
 101 +
 102  config NETFILTER_XT_TARGET_DSCP
 103         tristate '"DSCP" target support'
 104         depends on NETFILTER_XTABLES
 105 @@ -355,6 +371,14 @@
 106
 107           To compile it as a module, choose M here.  If unsure, say N.
 108
 109 +config NETFILTER_XT_MATCH_PORTSCAN
 110 +       tristate '"portscan" match support'
 111 +       depends on NETFILTER_XTABLES
 112 +       help
 113 +         This option adds a 'portscan' match support.
 114 +
 115 +         To compile it as a module, choose M here.  If unsure, say N.
 116 +
 117  config NETFILTER_XT_MATCH_MULTIPORT
 118         tristate "Multiple port match support"
 119         depends on NETFILTER_XTABLES
 120 diff -ruN linux-2.6.19.1.orig/net/netfilter/Makefile linux-2.6.19.1/net/netfilter/Makefile
 121 --- linux-2.6.19.1.orig/net/netfilter/Makefile  2007-01-11 13:27:24.445577700 +0100
 122 +++ linux-2.6.19.1/net/netfilter/Makefile       2007-01-11 13:28:07.656144799 +0100
 123 @@ -23,8 +23,10 @@
 124  obj-$(CONFIG_NETFILTER_XTABLES) += x_tables.o xt_tcpudp.o
 125
 126  # targets
 127 +obj-$(CONFIG_NETFILTER_XT_TARGET_CHAOS) += xt_CHAOS.o
 128  obj-$(CONFIG_NETFILTER_XT_TARGET_CLASSIFY) += xt_CLASSIFY.o
 129  obj-$(CONFIG_NETFILTER_XT_TARGET_CONNMARK) += xt_CONNMARK.o
 130 +obj-$(CONFIG_NETFILTER_XT_TARGET_DELUDE) += xt_DELUDE.o
 131  obj-$(CONFIG_NETFILTER_XT_TARGET_DSCP) += xt_DSCP.o
 132  obj-$(CONFIG_NETFILTER_XT_TARGET_MARK) += xt_MARK.o
 133  obj-$(CONFIG_NETFILTER_XT_TARGET_NFQUEUE) += xt_NFQUEUE.o
 134 @@ -47,6 +49,7 @@
 135  obj-$(CONFIG_NETFILTER_XT_MATCH_MARK) += xt_mark.o
 136  obj-$(CONFIG_NETFILTER_XT_MATCH_MULTIPORT) += xt_multiport.o
 137  obj-$(CONFIG_NETFILTER_XT_MATCH_POLICY) += xt_policy.o
 138 +obj-$(CONFIG_NETFILTER_XT_MATCH_PORTSCAN) += xt_portscan.o
 139  obj-$(CONFIG_NETFILTER_XT_MATCH_PKTTYPE) += xt_pkttype.o
 140  obj-$(CONFIG_NETFILTER_XT_MATCH_QUOTA) += xt_quota.o
 141  obj-$(CONFIG_NETFILTER_XT_MATCH_REALM) += xt_realm.o
 142 diff -ruN linux-2.6.19.1.orig/net/netfilter/xt_CHAOS.c linux-2.6.19.1/net/netfilter/xt_CHAOS.c
 143 --- linux-2.6.19.1.orig/net/netfilter/xt_CHAOS.c        1970-01-01 01:00:00.000000000 +0100
 144 +++ linux-2.6.19.1/net/netfilter/xt_CHAOS.c     2007-01-11 13:28:14.407920893 +0100
 145 @@ -0,0 +1,180 @@
 146 +/*
 147 +    CHAOS target for netfilter
 148 +
 149 +    Copyright © Jan Engelhardt <jengelh [at] gmx de>, 2006 - 2007
 150 +    released under the terms of the GNU General Public
 151 +    License version 2.x and only versions 2.x.
 152 +*/
 153 +#include <linux/icmp.h>
 154 +#include <linux/in.h>
 155 +#include <linux/ip.h>
 156 +#include <linux/module.h>
 157 +#include <linux/skbuff.h>
 158 +#include <linux/stat.h>
 159 +#include <linux/netfilter/x_tables.h>
 160 +#include <linux/netfilter/xt_tcpudp.h>
 161 +#include <linux/netfilter_ipv4/ipt_REJECT.h>
 162 +#include <net/ip.h>
 163 +#include <linux/netfilter/xt_CHAOS.h>
 164 +#include "find_match.c"
 165 +#define PFX KBUILD_MODNAME ": "
 166 +
 167 +/* Out of tree workarounds */
 168 +#include <linux/version.h>
 169 +#if LINUX_VERSION_CODE <= KERNEL_VERSION(2, 6, 18)
 170 +#    define HAVE_TARGUSERINFO 1
 171 +#endif
 172 +
 173 +/* Module parameters */
 174 +static unsigned int reject_percentage = ~0U * .01;
 175 +static unsigned int delude_percentage = ~0U * .0101;
 176 +module_param(reject_percentage, uint, S_IRUGO | S_IWUSR);
 177 +module_param(delude_percentage, uint, S_IRUGO | S_IWUSR);
 178 +
 179 +/* References to other matches/targets */
 180 +static struct xt_match *xm_tcp;
 181 +static struct xt_target *xt_delude, *xt_reject, *xt_tarpit;
 182 +
 183 +/* Static data for other matches/targets */
 184 +static const struct ipt_reject_info reject_params = {
 185 +       .with = ICMP_HOST_UNREACH,
 186 +};
 187 +
 188 +static const struct xt_tcp tcp_params = {
 189 +       .spts = {0, ~0},
 190 +       .dpts = {0, ~0},
 191 +};
 192 +
 193 +/* CHAOS functions */
 194 +static void xt_chaos_total(const struct xt_chaos_info *info,
 195 +    struct sk_buff **pskb, const struct net_device *in,
 196 +    const struct net_device *out, unsigned int hooknum)
 197 +{
 198 +       const int protoff = 4 * (*pskb)->nh.iph->ihl;
 199 +       const int offset  = ntohs((*pskb)->nh.iph->frag_off) & IP_OFFSET;
 200 +       const struct xt_target *destiny;
 201 +       int hotdrop = 0, ret;
 202 +
 203 +       ret = xm_tcp->match(*pskb, in, out, xm_tcp, &tcp_params,
 204 +                           offset, protoff, &hotdrop);
 205 +       if(!ret || hotdrop || (unsigned int)net_random() > delude_percentage)
 206 +               return;
 207 +
 208 +       destiny = (info->variant == XTCHAOS_TARPIT) ? xt_tarpit : xt_delude;
 209 +#ifdef HAVE_TARGUSERINFO
 210 +       destiny->target(pskb, in, out, hooknum, destiny, NULL, NULL);
 211 +#else
 212 +       destiny->target(pskb, in, out, hooknum, destiny, NULL);
 213 +#endif
 214 +       return;
 215 +}
 216 +
 217 +static unsigned int xt_chaos_target(struct sk_buff **pskb,
 218 +    const struct net_device *in, const struct net_device *out,
 219 +    unsigned int hooknum, const struct xt_target *target, const void *targinfo
 220 +#ifdef HAVE_TARGUSERINFO
 221 +    ,
 222 +    void *userinfo
 223 +#endif
 224 +    )
 225 +{
 226 +       /* Equivalent to:
 227 +        * -A chaos -m statistic --mode random --probability \
 228 +        *         $reject_percentage -j REJECT --reject-with host-unreach;
 229 +        * -A chaos -m statistic --mode random --probability \
 230 +        *         $delude_percentage -j DELUDE;
 231 +        * -A chaos -j DROP;
 232 +        */
 233 +       const struct xt_chaos_info *info = targinfo;
 234 +
 235 +       if((unsigned int)net_random() <= reject_percentage)
 236 +#ifdef HAVE_TARGUSERINFO
 237 +               return xt_reject->target(pskb, in, out, hooknum, target,
 238 +                      &reject_params, userinfo);
 239 +#else
 240 +               return xt_reject->target(pskb, in, out, hooknum, target,
 241 +                      &reject_params);
 242 +#endif
 243 +
 244 +       /* TARPIT/DELUDE may not be called from the OUTPUT chain */
 245 +       if((*pskb)->nh.iph->protocol == IPPROTO_TCP &&
 246 +         info->variant != XTCHAOS_NORMAL && hooknum != NF_IP_LOCAL_OUT)
 247 +               xt_chaos_total(info, pskb, in, out, hooknum);
 248 +
 249 +       return NF_DROP;
 250 +}
 251 +
 252 +static struct xt_target xt_chaos_info = {
 253 +       .name       = "CHAOS",
 254 +       .target     = xt_chaos_target,
 255 +       .table      = "filter",
 256 +       .targetsize = sizeof(struct xt_chaos_info),
 257 +       .hooks      = (1 << NF_IP_LOCAL_IN) | (1 << NF_IP_FORWARD) |
 258 +                     (1 << NF_IP_LOCAL_OUT),
 259 +       .family     = AF_INET,
 260 +       .me         = THIS_MODULE,
 261 +};
 262 +
 263 +static int __init xt_chaos_init(void)
 264 +{
 265 +       int ret = -EINVAL;
 266 +
 267 +       xm_tcp = xt_request_find_match(AF_INET, "tcp", 0);
 268 +       if(xm_tcp == NULL) {
 269 +               printk(KERN_WARNING PFX "Could not find \"tcp\" match\n");
 270 +               return -EINVAL;
 271 +       }
 272 +
 273 +       xt_reject = xt_request_find_target(AF_INET, "REJECT", 0);
 274 +       if(xt_reject == NULL) {
 275 +               printk(KERN_WARNING PFX "Could not find \"REJECT\" target\n");
 276 +               goto out2;
 277 +       }
 278 +
 279 +       xt_tarpit = xt_request_find_target(AF_INET, "TARPIT", 0);
 280 +       if(xt_tarpit == NULL) {
 281 +               printk(KERN_WARNING PFX "Could not find \"TARPIT\" target\n");
 282 +               goto out3;
 283 +       }
 284 +
 285 +       xt_delude = xt_request_find_target(AF_INET, "DELUDE", 0);
 286 +       if(xt_delude == NULL) {
 287 +               printk(KERN_WARNING PFX "Could not find \"DELUDE\" target\n");
 288 +               goto out4;
 289 +       }
 290 +
 291 +       if((ret = xt_register_target(&xt_chaos_info)) != 0) {
 292 +               printk(KERN_WARNING PFX "xt_register_target returned "
 293 +                      "error %d\n", ret);
 294 +               goto out5;
 295 +       }
 296 +
 297 +       return 0;
 298 +
 299 + out5:
 300 +       module_put(xt_delude->me);
 301 + out4:
 302 +       module_put(xt_tarpit->me);
 303 + out3:
 304 +       module_put(xt_reject->me);
 305 + out2:
 306 +       module_put(xm_tcp->me);
 307 +       return ret;
 308 +}
 309 +
 310 +static void __exit xt_chaos_exit(void)
 311 +{
 312 +       xt_unregister_target(&xt_chaos_info);
 313 +       module_put(xm_tcp->me);
 314 +       module_put(xt_reject->me);
 315 +       module_put(xt_delude->me);
 316 +       module_put(xt_tarpit->me);
 317 +       return;
 318 +}
 319 +
 320 +module_init(xt_chaos_init);
 321 +module_exit(xt_chaos_exit);
 322 +MODULE_AUTHOR("Jan Engelhardt <jengelh@gmx.de>");
 323 +MODULE_DESCRIPTION("netfilter CHAOS target");
 324 +MODULE_LICENSE("GPL");
 325 +MODULE_ALIAS("ipt_CHAOS");
 326 diff -ruN linux-2.6.19.1.orig/net/netfilter/xt_DELUDE.c linux-2.6.19.1/net/netfilter/xt_DELUDE.c
 327 --- linux-2.6.19.1.orig/net/netfilter/xt_DELUDE.c       1970-01-01 01:00:00.000000000 +0100
 328 +++ linux-2.6.19.1/net/netfilter/xt_DELUDE.c    2007-01-11 13:28:07.656144799 +0100
 329 @@ -0,0 +1,265 @@
 330 +/*
 331 +    DELUDE target
 332 +    Copyright © Jan Engelhardt <jengelh [at] gmx de>, 2007
 333 +
 334 +    Based upon linux-2.6.18.5/net/ipv4/netfilter/ipt_REJECT.c:
 335 +    (C) 1999-2001 Paul `Rusty' Russell
 336 +    (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
 337 +
 338 +    This program is free software; you can redistribute it and/or modify
 339 +    it under the terms of the GNU General Public License version 2 as
 340 +    published by the Free Software Foundation.
 341 +*/
 342 +
 343 +#include <linux/module.h>
 344 +#include <linux/skbuff.h>
 345 +#include <linux/ip.h>
 346 +#include <linux/tcp.h>
 347 +#include <linux/udp.h>
 348 +#include <linux/icmp.h>
 349 +#include <net/icmp.h>
 350 +#include <net/ip.h>
 351 +#include <net/tcp.h>
 352 +#include <net/route.h>
 353 +#include <net/dst.h>
 354 +#include <linux/netfilter_ipv4/ip_tables.h>
 355 +#ifdef CONFIG_BRIDGE_NETFILTER
 356 +#include <linux/netfilter_bridge.h>
 357 +#endif
 358 +#define PFX KBUILD_MODNAME ": "
 359 +
 360 +/* Out of tree workarounds */
 361 +#include <linux/version.h>
 362 +#if LINUX_VERSION_CODE <= KERNEL_VERSION(2, 6, 18)
 363 +#    define HAVE_TARGINFOSIZE 1
 364 +#    define HAVE_TARGUSERINFO 1
 365 +#endif
 366 +#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 20)
 367 +#    define nfmark mark
 368 +#endif
 369 +
 370 +static inline struct rtable *route_reverse(struct sk_buff *skb,
 371 +                                          struct tcphdr *tcph, int hook)
 372 +{
 373 +       struct iphdr *iph = skb->nh.iph;
 374 +       struct dst_entry *odst;
 375 +       struct flowi fl = {};
 376 +       struct rtable *rt;
 377 +
 378 +       /* We don't require ip forwarding to be enabled to be able to
 379 +        * send a RST reply for bridged traffic. */
 380 +       if (hook != NF_IP_FORWARD
 381 +#ifdef CONFIG_BRIDGE_NETFILTER
 382 +           || (skb->nf_bridge && skb->nf_bridge->mask & BRNF_BRIDGED)
 383 +#endif
 384 +          ) {
 385 +               fl.nl_u.ip4_u.daddr = iph->saddr;
 386 +               if (hook == NF_IP_LOCAL_IN)
 387 +                       fl.nl_u.ip4_u.saddr = iph->daddr;
 388 +               fl.nl_u.ip4_u.tos = RT_TOS(iph->tos);
 389 +
 390 +               if (ip_route_output_key(&rt, &fl) != 0)
 391 +                       return NULL;
 392 +       } else {
 393 +               /* non-local src, find valid iif to satisfy
 394 +                * rp-filter when calling ip_route_input. */
 395 +               fl.nl_u.ip4_u.daddr = iph->daddr;
 396 +               if (ip_route_output_key(&rt, &fl) != 0)
 397 +                       return NULL;
 398 +
 399 +               odst = skb->dst;
 400 +               if (ip_route_input(skb, iph->saddr, iph->daddr,
 401 +                                  RT_TOS(iph->tos), rt->u.dst.dev) != 0) {
 402 +                       dst_release(&rt->u.dst);
 403 +                       return NULL;
 404 +               }
 405 +               dst_release(&rt->u.dst);
 406 +               rt = (struct rtable *)skb->dst;
 407 +               skb->dst = odst;
 408 +
 409 +               fl.nl_u.ip4_u.daddr = iph->saddr;
 410 +               fl.nl_u.ip4_u.saddr = iph->daddr;
 411 +               fl.nl_u.ip4_u.tos = RT_TOS(iph->tos);
 412 +       }
 413 +
 414 +       if (rt->u.dst.error) {
 415 +               dst_release(&rt->u.dst);
 416 +               return NULL;
 417 +       }
 418 +
 419 +       fl.proto = IPPROTO_TCP;
 420 +       fl.fl_ip_sport = tcph->dest;
 421 +       fl.fl_ip_dport = tcph->source;
 422 +
 423 +       xfrm_lookup((struct dst_entry **)&rt, &fl, NULL, 0);
 424 +
 425 +       return rt;
 426 +}
 427 +
 428 +static void send_reset(struct sk_buff *oldskb, int hook)
 429 +{
 430 +       struct sk_buff *nskb;
 431 +       struct iphdr *iph = oldskb->nh.iph;
 432 +       struct tcphdr _otcph, *oth, *tcph;
 433 +       struct rtable *rt;
 434 +       u_int16_t tmp_port;
 435 +       u_int32_t tmp_addr;
 436 +       int hh_len;
 437 +
 438 +       /* IP header checks: fragment. */
 439 +       if (oldskb->nh.iph->frag_off & htons(IP_OFFSET))
 440 +               return;
 441 +
 442 +       oth = skb_header_pointer(oldskb, oldskb->nh.iph->ihl * 4,
 443 +                                sizeof(_otcph), &_otcph);
 444 +       if (oth == NULL)
 445 +               return;
 446 +
 447 +       /* DELUDE only answers SYN. */
 448 +       if(!oth->syn || oth->ack || oth->fin || oth->rst)
 449 +               return;
 450 +
 451 +       /* Check checksum */
 452 +       if (nf_ip_checksum(oldskb, hook, iph->ihl * 4, IPPROTO_TCP))
 453 +               return;
 454 +
 455 +       if ((rt = route_reverse(oldskb, oth, hook)) == NULL)
 456 +               return;
 457 +
 458 +       hh_len = LL_RESERVED_SPACE(rt->u.dst.dev);
 459 +
 460 +       /* We need a linear, writeable skb.  We also need to expand
 461 +          headroom in case hh_len of incoming interface < hh_len of
 462 +          outgoing interface */
 463 +       nskb = skb_copy_expand(oldskb, hh_len, skb_tailroom(oldskb),
 464 +                              GFP_ATOMIC);
 465 +       if (!nskb) {
 466 +               dst_release(&rt->u.dst);
 467 +               return;
 468 +       }
 469 +
 470 +       dst_release(nskb->dst);
 471 +       nskb->dst = &rt->u.dst;
 472 +
 473 +       /* This packet will not be the same as the other: clear nf fields */
 474 +       nf_reset(nskb);
 475 +       nskb->nfmark = 0;
 476 +       skb_init_secmark(nskb);
 477 +
 478 +       tcph = (struct tcphdr *)((u_int32_t*)nskb->nh.iph + nskb->nh.iph->ihl);
 479 +
 480 +       /* Swap source and dest */
 481 +       tmp_addr = nskb->nh.iph->saddr;
 482 +       nskb->nh.iph->saddr = nskb->nh.iph->daddr;
 483 +       nskb->nh.iph->daddr = tmp_addr;
 484 +       tmp_port = tcph->source;
 485 +       tcph->source = tcph->dest;
 486 +       tcph->dest = tmp_port;
 487 +
 488 +       /* Truncate to length (no data) */
 489 +       tcph->doff = sizeof(struct tcphdr)/4;
 490 +       skb_trim(nskb, nskb->nh.iph->ihl*4 + sizeof(struct tcphdr));
 491 +       nskb->nh.iph->tot_len = htons(nskb->len);
 492 +
 493 +       tcph->seq = oth->ack_seq;
 494 +       tcph->ack_seq = 0;
 495 +
 496 +       /* Reset flags */
 497 +       ((u_int8_t *)tcph)[13] = 0;
 498 +       tcph->syn = tcph->ack = 1;
 499 +
 500 +       tcph->window = 0;
 501 +       tcph->urg_ptr = 0;
 502 +
 503 +       /* Adjust TCP checksum */
 504 +       tcph->check = 0;
 505 +       tcph->check = tcp_v4_check(tcph, sizeof(struct tcphdr),
 506 +                                  nskb->nh.iph->saddr,
 507 +                                  nskb->nh.iph->daddr,
 508 +                                  csum_partial((char *)tcph,
 509 +                                               sizeof(struct tcphdr), 0));
 510 +
 511 +       /* Adjust IP TTL, DF */
 512 +       nskb->nh.iph->ttl = dst_metric(nskb->dst, RTAX_HOPLIMIT);
 513 +       /* Set DF, id = 0 */
 514 +       nskb->nh.iph->frag_off = htons(IP_DF);
 515 +       nskb->nh.iph->id = 0;
 516 +
 517 +       /* Adjust IP checksum */
 518 +       nskb->nh.iph->check = 0;
 519 +       nskb->nh.iph->check = ip_fast_csum((unsigned char *)nskb->nh.iph,
 520 +                                          nskb->nh.iph->ihl);
 521 +
 522 +       /* "Never happens" */
 523 +       if (nskb->len > dst_mtu(nskb->dst))
 524 +               goto free_nskb;
 525 +
 526 +       nf_ct_attach(nskb, oldskb);
 527 +
 528 +       NF_HOOK(PF_INET, NF_IP_LOCAL_OUT, nskb, NULL, nskb->dst->dev,
 529 +               dst_output);
 530 +       return;
 531 +
 532 + free_nskb:
 533 +       kfree_skb(nskb);
 534 +       return;
 535 +}
 536 +
 537 +static unsigned int xt_delude_target(struct sk_buff **pskb,
 538 +    const struct net_device *in, const struct net_device *out,
 539 +    unsigned int hooknum, const struct xt_target *target, const void *targinfo
 540 +#ifdef HAVE_TARGUSERINFO
 541 +    ,
 542 +    void *userinfo
 543 +#endif
 544 +    )
 545 +{
 546 +       /* WARNING: This code causes reentry within iptables.
 547 +          This means that the iptables jump stack is now crap.  We
 548 +          must return an absolute verdict. --RR */
 549 +       send_reset(*pskb, hooknum);
 550 +       return NF_DROP;
 551 +}
 552 +
 553 +static int xt_delude_check(const char *tablename, const void *e_void,
 554 +    const struct xt_target *target, void *targinfo,
 555 +#ifdef HAVE_TARGINFOSIZE
 556 +    unsigned int targinfosize,
 557 +#endif
 558 +    unsigned int hook_mask)
 559 +{
 560 +       if(hook_mask & ~((1 << NF_IP_LOCAL_IN) | (1 << NF_IP_FORWARD))) {
 561 +               printk(KERN_WARNING PFX "DELUDE may not be used in chains "
 562 +                      "other than INPUT and FORWARD\n");
 563 +               return 0;
 564 +       }
 565 +       return 1;
 566 +}
 567 +
 568 +static struct xt_target xt_delude_info = {
 569 +       .name       = "DELUDE",
 570 +       .target     = xt_delude_target,
 571 +       .checkentry = xt_delude_check,
 572 +       .table      = "filter",
 573 +       .hooks      = (1 << NF_IP_LOCAL_IN) | (1 << NF_IP_FORWARD) |
 574 +                     (1 << NF_IP_LOCAL_OUT),
 575 +       .proto      = IPPROTO_TCP,
 576 +       .family     = AF_INET,
 577 +       .me         = THIS_MODULE,
 578 +};
 579 +
 580 +static int __init xt_delude_init(void)
 581 +{
 582 +       return xt_register_target(&xt_delude_info);
 583 +}
 584 +
 585 +static void __exit xt_delude_exit(void)
 586 +{
 587 +       xt_unregister_target(&xt_delude_info);
 588 +}
 589 +
 590 +module_init(xt_delude_init);
 591 +module_exit(xt_delude_exit);
 592 +MODULE_LICENSE("GPL");
 593 +MODULE_AUTHOR("Jan Engelhardt <jengelh@gmx.de>");
 594 +MODULE_DESCRIPTION("netfilter DELUDE target");
 595 diff -ruN linux-2.6.19.1.orig/net/netfilter/xt_portscan.c linux-2.6.19.1/net/netfilter/xt_portscan.c
 596 --- linux-2.6.19.1.orig/net/netfilter/xt_portscan.c     1970-01-01 01:00:00.000000000 +0100
 597 +++ linux-2.6.19.1/net/netfilter/xt_portscan.c  2007-01-11 13:28:14.407920893 +0100
 598 @@ -0,0 +1,282 @@
 599 +/*
 600 +    portscan match for netfilter
 601 +
 602 +    Written by Jan Engelhardt, 2006 - 2007
 603 +    released under the terms of the GNU General Public
 604 +    License version 2.x and only versions 2.x.
 605 +*/
 606 +#include <linux/in.h>
 607 +#include <linux/ip.h>
 608 +#include <linux/module.h>
 609 +#include <linux/moduleparam.h>
 610 +#include <linux/skbuff.h>
 611 +#include <linux/stat.h>
 612 +#include <linux/tcp.h>
 613 +#include <linux/types.h>
 614 +#include <linux/version.h>
 615 +#include <linux/netfilter/x_tables.h>
 616 +#include <linux/netfilter/xt_tcpudp.h>
 617 +#if defined(CONFIG_IP_NF_CONNTRACK) || defined(CONFIG_IP_NF_CONNTRACK_MODULE)
 618 +#    include <linux/netfilter_ipv4/ip_conntrack.h>
 619 +#else /* linux-2.6.20+ */
 620 +#    include <net/netfilter/nf_nat_rule.h>
 621 +#endif
 622 +#include <linux/netfilter/xt_portscan.h>
 623 +#define PFX KBUILD_MODNAME ": "
 624 +
 625 +/* Out of tree workarounds */
 626 +#if LINUX_VERSION_CODE <= KERNEL_VERSION(2, 6, 18)
 627 +#    define HAVE_MATCHINFOSIZE 1
 628 +#endif
 629 +#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 20)
 630 +#    define nfmark mark
 631 +#endif
 632 +
 633 +enum {
 634 +       TCP_FLAGS_ALL3 = TCP_FLAG_FIN | TCP_FLAG_RST | TCP_FLAG_SYN,
 635 +       TCP_FLAGS_ALL4 = TCP_FLAGS_ALL3 | TCP_FLAG_ACK,
 636 +       TCP_FLAGS_ALL6 = TCP_FLAGS_ALL4 | TCP_FLAG_PSH | TCP_FLAG_URG,
 637 +};
 638 +
 639 +/* Module parameters */
 640 +static unsigned int
 641 +       connmark_mask = ~0,
 642 +       packet_mask   = ~0,
 643 +       mark_seen     = 0x9,
 644 +       mark_synrcv   = 0x1,
 645 +       mark_closed   = 0x2,
 646 +       mark_synscan  = 0x3,
 647 +       mark_estab1   = 0x4,
 648 +       mark_estab2   = 0x5,
 649 +       mark_cnscan   = 0x6,
 650 +       mark_grscan   = 0x7,
 651 +       mark_valid    = 0x8;
 652 +
 653 +module_param(connmark_mask, uint, S_IRUGO | S_IWUSR);
 654 +module_param(packet_mask,   uint, S_IRUGO | S_IWUSR);
 655 +module_param(mark_seen,     uint, S_IRUGO | S_IWUSR);
 656 +module_param(mark_synrcv,   uint, S_IRUGO | S_IWUSR);
 657 +module_param(mark_closed,   uint, S_IRUGO | S_IWUSR);
 658 +module_param(mark_synscan,  uint, S_IRUGO | S_IWUSR);
 659 +module_param(mark_estab1,   uint, S_IRUGO | S_IWUSR);
 660 +module_param(mark_estab2,   uint, S_IRUGO | S_IWUSR);
 661 +module_param(mark_cnscan,   uint, S_IRUGO | S_IWUSR);
 662 +module_param(mark_grscan,   uint, S_IRUGO | S_IWUSR);
 663 +module_param(mark_valid,    uint, S_IRUGO | S_IWUSR);
 664 +MODULE_PARM_DESC(connmark_mask, "only set specified bits in connection mark");
 665 +MODULE_PARM_DESC(packet_mask,   "only set specified bits in packet mark");
 666 +MODULE_PARM_DESC(mark_seen,     "nfmark value for packet-seen state");
 667 +MODULE_PARM_DESC(mark_synrcv,   "connmark value for SYN Received state");
 668 +MODULE_PARM_DESC(mark_closed,   "connmark value for closed state");
 669 +MODULE_PARM_DESC(mark_synscan,  "connmark value for SYN Scan state");
 670 +MODULE_PARM_DESC(mark_estab1,   "connmark value for Established-1 state");
 671 +MODULE_PARM_DESC(mark_estab2,   "connmark value for Established-2 state");
 672 +MODULE_PARM_DESC(mark_cnscan,   "connmark value for Connect Scan state");
 673 +MODULE_PARM_DESC(mark_grscan,   "connmark value for Grab Scan state");
 674 +MODULE_PARM_DESC(mark_valid,    "connmark value for Valid state");
 675 +
 676 +/* TCP flag functions */
 677 +static inline int tflg_ack4(const struct tcphdr *th)
 678 +{
 679 +       return (tcp_flag_word(th) & TCP_FLAGS_ALL4) == TCP_FLAG_ACK;
 680 +}
 681 +
 682 +static inline int tflg_ack6(const struct tcphdr *th)
 683 +{
 684 +       return (tcp_flag_word(th) & TCP_FLAGS_ALL6) == TCP_FLAG_ACK;
 685 +}
 686 +
 687 +static inline int tflg_fin(const struct tcphdr *th)
 688 +{
 689 +       return (tcp_flag_word(th) & TCP_FLAGS_ALL3) == TCP_FLAG_FIN;
 690 +}
 691 +
 692 +static inline int tflg_rst(const struct tcphdr *th)
 693 +{
 694 +       return (tcp_flag_word(th) & TCP_FLAGS_ALL3) == TCP_FLAG_RST;
 695 +}
 696 +
 697 +static inline int tflg_rstack(const struct tcphdr *th)
 698 +{
 699 +       return (tcp_flag_word(th) & TCP_FLAGS_ALL4) ==
 700 +              (TCP_FLAG_ACK | TCP_FLAG_RST);
 701 +}
 702 +
 703 +static inline int tflg_syn(const struct tcphdr *th)
 704 +{
 705 +       return (tcp_flag_word(th) & TCP_FLAGS_ALL4) == TCP_FLAG_SYN;
 706 +}
 707 +
 708 +static inline int tflg_synack(const struct tcphdr *th)
 709 +{
 710 +       return (tcp_flag_word(th) & TCP_FLAGS_ALL4) ==
 711 +              (TCP_FLAG_SYN | TCP_FLAG_ACK);
 712 +}
 713 +
 714 +/* portscan functions */
 715 +static inline int xt_portscan_stealth(const struct tcphdr *th)
 716 +{
 717 +       /*
 718 +        * "Connection refused" replies to our own probes must not be matched.
 719 +        */
 720 +       if(tflg_rstack(th))
 721 +               return 0;
 722 +
 723 +       if(tflg_rst(th) && printk_ratelimit()) {
 724 +               printk(KERN_WARNING PFX "Warning: Pure RST received\n");
 725 +               return 0;
 726 +       }
 727 +
 728 +       /*
 729 +        * -p tcp ! --syn -m conntrack --ctstate INVALID: Looking for non-start
 730 +        * packets that are not associated with any connection -- this will
 731 +        * match most scan types (NULL, XMAS, FIN) and ridiculous flag
 732 +        * combinations (SYN-RST, SYN-FIN, SYN-FIN-RST, FIN-RST, etc.).
 733 +        */
 734 +       return !tflg_syn(th);
 735 +}
 736 +
 737 +static inline int xt_portscan_full(int mark, enum ip_conntrack_info ctstate,
 738 +    int loopback, const struct tcphdr *tcph, int payload_len)
 739 +{
 740 +       if(mark == mark_estab2) {
 741 +               /*
 742 +                * -m connmark --mark $ESTAB2
 743 +                */
 744 +               if(tflg_ack4(tcph) && payload_len == 0)
 745 +                       return mark; /* keep mark */
 746 +               else if(tflg_rst(tcph) || tflg_fin(tcph))
 747 +                       return mark_grscan;
 748 +               else
 749 +                       return mark_valid;
 750 +       } else if(mark == mark_estab1) {
 751 +               /*
 752 +                * -m connmark --mark $ESTAB1
 753 +                */
 754 +               if(tflg_rst(tcph) || tflg_fin(tcph))
 755 +                       return mark_cnscan;
 756 +               else if(!loopback && tflg_ack4(tcph) && payload_len == 0)
 757 +                       return mark_estab2;
 758 +               else
 759 +                       return mark_valid;
 760 +       } else if(mark == mark_synrcv) {
 761 +               /*
 762 +                * -m connmark --mark $SYN
 763 +                */
 764 +               if(loopback && tflg_synack(tcph))
 765 +                       return mark; /* keep mark */
 766 +               else if(loopback && tflg_rstack(tcph))
 767 +                       return mark_closed;
 768 +               else if(tflg_ack6(tcph))
 769 +                       return mark_estab1;
 770 +               else
 771 +                       return mark_synscan;
 772 +       } else if(ctstate == IP_CT_NEW && tflg_syn(tcph)) {
 773 +               /*
 774 +                * -p tcp --syn --ctstate NEW
 775 +                */
 776 +               return mark_synrcv;
 777 +       }
 778 +       return mark;
 779 +}
 780 +
 781 +static int xt_portscan_match(const struct sk_buff *skb,
 782 +    const struct net_device *in, const struct net_device *out,
 783 +    const struct xt_match *match, const void *matchinfo, int offset,
 784 +    unsigned int protoff, int *hotdrop)
 785 +{
 786 +       const struct xt_portscan_info *info = matchinfo;
 787 +       enum ip_conntrack_info ctstate;
 788 +       struct ip_conntrack *ctdata;
 789 +       const struct tcphdr *tcph;
 790 +       struct tcphdr tcph_buf;
 791 +
 792 +       tcph = skb_header_pointer(skb, protoff, sizeof(tcph_buf), &tcph_buf);
 793 +       if(tcph == NULL)
 794 +               return 0;
 795 +
 796 +       /* Check for invalid packets: -m conntrack --ctstate INVALID */
 797 +       if((ctdata = ip_conntrack_get(skb, &ctstate)) == NULL) {
 798 +               if(info->match_stealth)
 799 +                       return xt_portscan_stealth(tcph);
 800 +               /*
 801 +                * If @ctdata is NULL, we cannot match the other scan
 802 +                * types, return.
 803 +                */
 804 +               return 0;
 805 +       }
 806 +
 807 +       /*
 808 +        * If -m portscan was previously applied to this packet, the rules we
 809 +        * simulate must not be run through again. And for speedup, do not call
 810 +        * it either when the connection is already VALID.
 811 +        */
 812 +       if((ctdata->mark & connmark_mask) == mark_valid ||
 813 +         (skb->nfmark & packet_mask) != mark_seen)
 814 +       {
 815 +               unsigned int n;
 816 +               n = xt_portscan_full(ctdata->mark & connmark_mask, ctstate,
 817 +                   in == &loopback_dev, tcph,
 818 +                   skb->len - protoff - 4 * tcph->doff);
 819 +
 820 +               ctdata->mark = (ctdata->mark & ~connmark_mask) | n;
 821 +               ((struct sk_buff *)skb)->nfmark =
 822 +                       (skb->nfmark & ~packet_mask) | mark_seen;
 823 +       }
 824 +
 825 +       return (info->match_syn && ctdata->mark == mark_synscan) ||
 826 +              (info->match_cn && ctdata->mark == mark_cnscan) ||
 827 +              (info->match_gr && ctdata->mark == mark_grscan);
 828 +}
 829 +
 830 +static int xt_portscan_checkentry(const char *tablename, const void *entry,
 831 +    const struct xt_match *match, void *matchinfo,
 832 +#ifdef HAVE_MATCHINFOSIZE
 833 +    unsigned int matchinfosize,
 834 +#endif
 835 +    unsigned int hook_mask)
 836 +{
 837 +       const struct xt_portscan_info *info = matchinfo;
 838 +#ifdef HAVE_MATCHINFOSIZE
 839 +       if(matchinfosize != XT_ALIGN(sizeof(struct xt_portscan_info))) {
 840 +               printk(KERN_WARNING PFX "matchinfosize %u != %Zu\n",
 841 +                      matchinfosize,
 842 +                      XT_ALIGN(sizeof(struct xt_portscan_info)));
 843 +               return 0;
 844 +       }
 845 +#endif
 846 +       if((info->match_stealth & ~1) || (info->match_syn & ~1) ||
 847 +         (info->match_cn & ~1) || (info->match_gr & ~1)) {
 848 +               printk(KERN_WARNING PFX "Invalid flags\n");
 849 +               return 0;
 850 +       }
 851 +       return 1;
 852 +}
 853 +
 854 +static struct xt_match xt_portscan = {
 855 +       .name       = "portscan",
 856 +       .match      = xt_portscan_match,
 857 +       .checkentry = xt_portscan_checkentry,
 858 +       .matchsize  = sizeof(struct xt_portscan_info),
 859 +       .proto      = IPPROTO_TCP,
 860 +       .family     = AF_INET,
 861 +       .me         = THIS_MODULE,
 862 +};
 863 +
 864 +static int __init xt_portscan_init(void)
 865 +{
 866 +       return xt_register_match(&xt_portscan);
 867 +}
 868 +
 869 +static void __exit xt_portscan_exit(void)
 870 +{
 871 +       xt_unregister_match(&xt_portscan);
 872 +       return;
 873 +}
 874 +
 875 +module_init(xt_portscan_init);
 876 +module_exit(xt_portscan_exit);
 877 +MODULE_AUTHOR("Jan Engelhardt <jengelh@gmx.de>");
 878 +MODULE_DESCRIPTION("netfilter portscan match module");
 879 +MODULE_LICENSE("GPL");
 880 +MODULE_ALIAS("ipt_portscan");