target/linux/generic-2.6/patches/170-netfilter_chaostables_0.8.patch

   1 Index: linux-2.6.21.7/include/linux/netfilter/oot_conntrack.h
   2 ===================================================================
   3 --- /dev/null
   4 +++ linux-2.6.21.7/include/linux/netfilter/oot_conntrack.h
   5 @@ -0,0 +1,5 @@
   6 +#if defined(CONFIG_IP_NF_CONNTRACK) || defined(CONFIG_IP_NF_CONNTRACK_MODULE)
   7 +#      include <linux/netfilter_ipv4/ip_conntrack.h>
   8 +#else /* linux-2.6.20+ */
   9 +#      include <net/netfilter/nf_nat_rule.h>
  10 +#endif
  11 Index: linux-2.6.21.7/include/linux/netfilter/oot_trans.h
  12 ===================================================================
  13 --- /dev/null
  14 +++ linux-2.6.21.7/include/linux/netfilter/oot_trans.h
  15 @@ -0,0 +1,14 @@
  16 +/* Out of tree workarounds */
  17 +#include <linux/version.h>
  18 +#if LINUX_VERSION_CODE <= KERNEL_VERSION(2, 6, 18)
  19 +#      define HAVE_MATCHINFOSIZE 1
  20 +#      define HAVE_TARGUSERINFO 1
  21 +#      define HAVE_TARGINFOSIZE 1
  22 +#endif
  23 +#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 20)
  24 +#      define nfmark mark
  25 +#endif
  26 +#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 21)
  27 +#      define tcp_v4_check(tcph, tcph_sz, s, d, csp) \
  28 +               tcp_v4_check((tcph_sz), (s), (d), (csp))
  29 +#endif
  30 Index: linux-2.6.21.7/include/linux/netfilter/xt_CHAOS.h
  31 ===================================================================
  32 --- /dev/null
  33 +++ linux-2.6.21.7/include/linux/netfilter/xt_CHAOS.h
  34 @@ -0,0 +1,14 @@
  35 +#ifndef _LINUX_NETFILTER_XT_CHAOS_H
  36 +#define _LINUX_NETFILTER_XT_CHAOS_H 1
  37 +
  38 +enum xt_chaos_target_variant {
  39 +       XTCHAOS_NORMAL,
  40 +       XTCHAOS_TARPIT,
  41 +       XTCHAOS_DELUDE,
  42 +};
  43 +
  44 +struct xt_chaos_target_info {
  45 +       uint8_t variant;
  46 +};
  47 +
  48 +#endif /* _LINUX_NETFILTER_XT_CHAOS_H */
  49 Index: linux-2.6.21.7/include/linux/netfilter/xt_portscan.h
  50 ===================================================================
  51 --- /dev/null
  52 +++ linux-2.6.21.7/include/linux/netfilter/xt_portscan.h
  53 @@ -0,0 +1,8 @@
  54 +#ifndef _LINUX_NETFILTER_XT_PORTSCAN_H
  55 +#define _LINUX_NETFILTER_XT_PORTSCAN_H 1
  56 +
  57 +struct xt_portscan_match_info {
  58 +       uint8_t match_stealth, match_syn, match_cn, match_gr;
  59 +};
  60 +
  61 +#endif /* _LINUX_NETFILTER_XT_PORTSCAN_H */
  62 Index: linux-2.6.21.7/net/netfilter/find_match.c
  63 ===================================================================
  64 --- /dev/null
  65 +++ linux-2.6.21.7/net/netfilter/find_match.c
  66 @@ -0,0 +1,39 @@
  67 +/*
  68 +    xt_request_find_match
  69 +    by Jan Engelhardt <jengelh [at] gmx de>, 2006 - 2007
  70 +
  71 +    Based upon linux-2.6.18.5/net/netfilter/x_tables.c:
  72 +    Copyright (C) 2006-2006 Harald Welte <laforge@netfilter.org>
  73 +    This program is free software; you can redistribute it and/or modify
  74 +    it under the terms of the GNU General Public License version 2 as
  75 +    published by the Free Software Foundation.
  76 +*/
  77 +#include <linux/err.h>
  78 +#include <linux/netfilter_arp.h>
  79 +#include <linux/socket.h>
  80 +#include <linux/netfilter/x_tables.h>
  81 +
  82 +/*
  83 + * Yeah this code is sub-optimal, but the function is missing in
  84 + * mainline so far. -jengelh
  85 + */
  86 +static struct xt_match *xt_request_find_match_lo(int af, const char *name,
  87 +    u8 revision)
  88 +{
  89 +       static const char *const xt_prefix[] = {
  90 +               [AF_INET]  = "ip",
  91 +               [AF_INET6] = "ip6",
  92 +               [NF_ARP]   = "arp",
  93 +       };
  94 +       struct xt_match *match;
  95 +
  96 +       match = try_then_request_module(xt_find_match(af, name, revision),
  97 +               "%st_%s", xt_prefix[af], name);
  98 +       if (IS_ERR(match) || match == NULL)
  99 +               return NULL;
 100 +
 101 +       return match;
 102 +}
 103 +
 104 +/* In case it goes into mainline, let this out-of-tree package compile */
 105 +#define xt_request_find_match xt_request_find_match_lo
 106 Index: linux-2.6.21.7/net/netfilter/Kconfig
 107 ===================================================================
 108 --- linux-2.6.21.7.orig/net/netfilter/Kconfig
 109 +++ linux-2.6.21.7/net/netfilter/Kconfig
 110 @@ -287,6 +287,14 @@ config NETFILTER_XTABLES
 111
 112  # alphabetically ordered list of targets
 113
 114 +config NETFILTER_XT_TARGET_CHAOS
 115 +       tristate '"CHAOS" target support'
 116 +       depends on NETFILTER_XTABLES
 117 +       help
 118 +         This option adds a `CHAOS' target.
 119 +
 120 +         To compile it as a module, choose M here.  If unsure, say N.
 121 +
 122  config NETFILTER_XT_TARGET_CLASSIFY
 123         tristate '"CLASSIFY" target support'
 124         depends on NETFILTER_XTABLES
 125 @@ -315,6 +323,14 @@ config NETFILTER_XT_TARGET_CONNMARK
 126           <file:Documentation/modules.txt>.  The module will be called
 127           ipt_CONNMARK.o.  If unsure, say `N'.
 128
 129 +config NETFILTER_XT_TARGET_DELUDE
 130 +       tristate '"DELUDE" target support'
 131 +       depends on NETFILTER_XTABLES
 132 +       help
 133 +         This option adds a `DELUDE' target.
 134 +
 135 +         To compile it as a module, choose M here.  If unsure, say N.
 136 +
 137  config NETFILTER_XT_TARGET_DSCP
 138         tristate '"DSCP" target support'
 139         depends on NETFILTER_XTABLES
 140 @@ -563,6 +579,14 @@ config NETFILTER_XT_MATCH_POLICY
 141
 142           To compile it as a module, choose M here.  If unsure, say N.
 143
 144 +config NETFILTER_XT_MATCH_PORTSCAN
 145 +       tristate '"portscan" match support'
 146 +       depends on NETFILTER_XTABLES
 147 +       help
 148 +         This option adds a 'portscan' match support.
 149 +
 150 +         To compile it as a module, choose M here.  If unsure, say N.
 151 +
 152  config NETFILTER_XT_MATCH_MULTIPORT
 153         tristate "Multiple port match support"
 154         depends on NETFILTER_XTABLES
 155 Index: linux-2.6.21.7/net/netfilter/Makefile
 156 ===================================================================
 157 --- linux-2.6.21.7.orig/net/netfilter/Makefile
 158 +++ linux-2.6.21.7/net/netfilter/Makefile
 159 @@ -47,6 +47,8 @@ obj-$(CONFIG_NETFILTER_XT_TARGET_NOTRACK
 160  obj-$(CONFIG_NETFILTER_XT_TARGET_SECMARK) += xt_SECMARK.o
 161  obj-$(CONFIG_NETFILTER_XT_TARGET_TCPMSS) += xt_TCPMSS.o
 162  obj-$(CONFIG_NETFILTER_XT_TARGET_CONNSECMARK) += xt_CONNSECMARK.o
 163 +obj-$(CONFIG_NETFILTER_XT_TARGET_CHAOS) += xt_CHAOS.o
 164 +obj-$(CONFIG_NETFILTER_XT_TARGET_DELUDE) += xt_DELUDE.o
 165
 166  # matches
 167  obj-$(CONFIG_NETFILTER_XT_MATCH_COMMENT) += xt_comment.o
 168 @@ -74,3 +76,4 @@ obj-$(CONFIG_NETFILTER_XT_MATCH_STRING)
 169  obj-$(CONFIG_NETFILTER_XT_MATCH_TCPMSS) += xt_tcpmss.o
 170  obj-$(CONFIG_NETFILTER_XT_MATCH_PHYSDEV) += xt_physdev.o
 171  obj-$(CONFIG_NETFILTER_XT_MATCH_HASHLIMIT) += xt_hashlimit.o
 172 +obj-$(CONFIG_NETFILTER_XT_MATCH_PORTSCAN) += xt_portscan.o
 173 Index: linux-2.6.21.7/net/netfilter/xt_CHAOS.c
 174 ===================================================================
 175 --- /dev/null
 176 +++ linux-2.6.21.7/net/netfilter/xt_CHAOS.c
 177 @@ -0,0 +1,200 @@
 178 +/*
 179 + *     CHAOS target for netfilter
 180 + *     Copyright © CC Computer Consultants GmbH, 2006 - 2007
 181 + *     Contact: Jan Engelhardt <jengelh@computergmbh.de>
 182 + *
 183 + *     This program is free software; you can redistribute it and/or modify
 184 + *     it under the terms of the GNU General Public License; either version
 185 + *     2 or 3 as published by the Free Software Foundation.
 186 + */
 187 +#include <linux/icmp.h>
 188 +#include <linux/in.h>
 189 +#include <linux/ip.h>
 190 +#include <linux/module.h>
 191 +#include <linux/skbuff.h>
 192 +#include <linux/stat.h>
 193 +#include <linux/netfilter/x_tables.h>
 194 +#include <linux/netfilter/xt_tcpudp.h>
 195 +#include <linux/netfilter_ipv4/ipt_REJECT.h>
 196 +#include <net/ip.h>
 197 +#if defined(_LOCAL)
 198 +#      include "xt_CHAOS.h"
 199 +#      include "find_match.c"
 200 +#elif defined(CONFIG_NETFILTER_XT_TARGET_CHAOS) || \
 201 +    defined(CONFIG_NETFILTER_XT_TARGET_CHAOS_MODULE)
 202 +#      include <linux/netfilter/xt_CHAOS.h>
 203 +#      include "find_match.c"
 204 +#else
 205 +#      include "xt_CHAOS.h"
 206 +#      include "find_match.c"
 207 +#endif
 208 +#define PFX KBUILD_MODNAME ": "
 209 +
 210 +/* Module parameters */
 211 +static unsigned int reject_percentage = ~0U * .01;
 212 +static unsigned int delude_percentage = ~0U * .0101;
 213 +module_param(reject_percentage, uint, S_IRUGO | S_IWUSR);
 214 +module_param(delude_percentage, uint, S_IRUGO | S_IWUSR);
 215 +
 216 +/* References to other matches/targets */
 217 +static struct xt_match *xm_tcp;
 218 +static struct xt_target *xt_delude, *xt_reject, *xt_tarpit;
 219 +
 220 +static int have_delude, have_tarpit;
 221 +
 222 +/* Static data for other matches/targets */
 223 +static const struct ipt_reject_info reject_params = {
 224 +       .with = ICMP_HOST_UNREACH,
 225 +};
 226 +
 227 +static const struct xt_tcp tcp_params = {
 228 +       .spts = {0, ~0},
 229 +       .dpts = {0, ~0},
 230 +};
 231 +
 232 +/* CHAOS functions */
 233 +static void xt_chaos_total(const struct xt_chaos_target_info *info,
 234 +    struct sk_buff **pskb, const struct net_device *in,
 235 +    const struct net_device *out, unsigned int hooknum)
 236 +{
 237 +       const struct iphdr *iph = ip_hdr(*pskb);
 238 +       const int protoff       = 4 * iph->ihl;
 239 +       const int offset        = ntohs(iph->frag_off) & IP_OFFSET;
 240 +       const struct xt_target *destiny;
 241 +       int hotdrop = 0, ret;
 242 +
 243 +       ret = xm_tcp->match(*pskb, in, out, xm_tcp, &tcp_params,
 244 +                           offset, protoff, &hotdrop);
 245 +       if (!ret || hotdrop || (unsigned int)net_random() > delude_percentage)
 246 +               return;
 247 +
 248 +       destiny = (info->variant == XTCHAOS_TARPIT) ? xt_tarpit : xt_delude;
 249 +       destiny->target(pskb, in, out, hooknum, destiny, NULL);
 250 +       return;
 251 +}
 252 +
 253 +static unsigned int chaos_tg(struct sk_buff **pskb,
 254 +    const struct net_device *in, const struct net_device *out,
 255 +    unsigned int hooknum, const struct xt_target *target, const void *targinfo)
 256 +{
 257 +       /*
 258 +        * Equivalent to:
 259 +        * -A chaos -m statistic --mode random --probability \
 260 +        *         $reject_percentage -j REJECT --reject-with host-unreach;
 261 +        * -A chaos -p tcp -m statistic --mode random --probability \
 262 +        *         $delude_percentage -j DELUDE;
 263 +        * -A chaos -j DROP;
 264 +        */
 265 +       const struct xt_chaos_target_info *info = targinfo;
 266 +       const struct iphdr *iph = ip_hdr(*pskb);
 267 +
 268 +       if ((unsigned int)net_random() <= reject_percentage)
 269 +               return xt_reject->target(pskb, in, out, hooknum, target,
 270 +                      &reject_params);
 271 +
 272 +       /* TARPIT/DELUDE may not be called from the OUTPUT chain */
 273 +       if (iph->protocol == IPPROTO_TCP &&
 274 +           info->variant != XTCHAOS_NORMAL && hooknum != NF_IP_LOCAL_OUT)
 275 +               xt_chaos_total(info, pskb, in, out, hooknum);
 276 +
 277 +       return NF_DROP;
 278 +}
 279 +
 280 +static int chaos_tg_check(const char *tablename, const void *entry,
 281 +    const struct xt_target *target, void *targinfo, unsigned int hook_mask)
 282 +{
 283 +       const struct xt_chaos_target_info *info = targinfo;
 284 +
 285 +       if (info->variant == XTCHAOS_DELUDE && !have_delude) {
 286 +               printk(KERN_WARNING PFX "Error: Cannot use --delude when "
 287 +                      "DELUDE module not available\n");
 288 +               return false;
 289 +       }
 290 +       if (info->variant == XTCHAOS_TARPIT && !have_tarpit) {
 291 +               printk(KERN_WARNING PFX "Error: Cannot use --tarpit when "
 292 +                      "TARPIT module not available\n");
 293 +               return false;
 294 +       }
 295 +
 296 +       return true;
 297 +}
 298 +
 299 +static struct xt_target chaos_tg_reg = {
 300 +       .name       = "CHAOS",
 301 +       .family     = AF_INET,
 302 +       .table      = "filter",
 303 +       .hooks      = (1 << NF_IP_LOCAL_IN) | (1 << NF_IP_FORWARD) |
 304 +                     (1 << NF_IP_LOCAL_OUT),
 305 +       .checkentry = chaos_tg_check,
 306 +       .target     = chaos_tg,
 307 +       .targetsize = sizeof(struct xt_chaos_target_info),
 308 +       .me         = THIS_MODULE,
 309 +};
 310 +
 311 +static int __init chaos_tg_init(void)
 312 +{
 313 +       int ret = -EINVAL;
 314 +
 315 +       xm_tcp = xt_request_find_match(AF_INET, "tcp", 0);
 316 +       if (xm_tcp == NULL) {
 317 +               printk(KERN_WARNING PFX "Error: Could not find or load "
 318 +                      "\"tcp\" match\n");
 319 +               return -EINVAL;
 320 +       }
 321 +
 322 +       xt_reject = xt_request_find_target(AF_INET, "REJECT", 0);
 323 +       if (xt_reject == NULL) {
 324 +               printk(KERN_WARNING PFX "Error: Could not find or load "
 325 +                      "\"REJECT\" target\n");
 326 +               goto out2;
 327 +       }
 328 +
 329 +       xt_tarpit   = xt_request_find_target(AF_INET, "TARPIT", 0);
 330 +       have_tarpit = xt_tarpit != NULL;
 331 +       if (!have_tarpit)
 332 +               printk(KERN_WARNING PFX "Warning: Could not find or load "
 333 +                      "\"TARPIT\" target\n");
 334 +
 335 +       xt_delude   = xt_request_find_target(AF_INET, "DELUDE", 0);
 336 +       have_delude = xt_delude != NULL;
 337 +       if (!have_delude)
 338 +               printk(KERN_WARNING PFX "Warning: Could not find or load "
 339 +                      "\"DELUDE\" target\n");
 340 +
 341 +       if ((ret = xt_register_target(&chaos_tg_reg)) != 0) {
 342 +               printk(KERN_WARNING PFX "xt_register_target returned "
 343 +                      "error %d\n", ret);
 344 +               goto out3;
 345 +       }
 346 +
 347 +       return 0;
 348 +
 349 + out3:
 350 +       if (have_delude)
 351 +               module_put(xt_delude->me);
 352 +       if (have_tarpit)
 353 +               module_put(xt_tarpit->me);
 354 +       module_put(xt_reject->me);
 355 + out2:
 356 +       module_put(xm_tcp->me);
 357 +       return ret;
 358 +}
 359 +
 360 +static void __exit chaos_tg_exit(void)
 361 +{
 362 +       xt_unregister_target(&chaos_tg_reg);
 363 +       module_put(xm_tcp->me);
 364 +       module_put(xt_reject->me);
 365 +       if (have_delude)
 366 +               module_put(xt_delude->me);
 367 +       if (have_tarpit)
 368 +               module_put(xt_tarpit->me);
 369 +       return;
 370 +}
 371 +
 372 +module_init(chaos_tg_init);
 373 +module_exit(chaos_tg_exit);
 374 +MODULE_AUTHOR("Jan Engelhardt <jengelh@computergmbh.de>");
 375 +MODULE_DESCRIPTION("netfilter \"CHAOS\" target");
 376 +MODULE_LICENSE("GPL");
 377 +MODULE_ALIAS("ipt_CHAOS");
 378 Index: linux-2.6.21.7/net/netfilter/xt_DELUDE.c
 379 ===================================================================
 380 --- /dev/null
 381 +++ linux-2.6.21.7/net/netfilter/xt_DELUDE.c
 382 @@ -0,0 +1,197 @@
 383 +/*
 384 + *     DELUDE target
 385 + *     Copyright © CC Computer Consultants GmbH, 2007
 386 + *     Contact: Jan Engelhardt <jengelh@computergmbh.de>
 387 + *
 388 + *     Based upon linux-2.6.18.5/net/ipv4/netfilter/ipt_REJECT.c:
 389 + *     (C) 1999-2001 Paul `Rusty' Russell
 390 + *     (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
 391 + *
 392 + *     xt_DELUDE acts like REJECT, but does reply with SYN-ACK on SYN.
 393 + *
 394 + *     This program is free software; you can redistribute it and/or modify
 395 + *     it under the terms of the GNU General Public License version 2 as
 396 + *     published by the Free Software Foundation.
 397 + */
 398 +#include <linux/module.h>
 399 +#include <linux/skbuff.h>
 400 +#include <linux/ip.h>
 401 +#include <linux/tcp.h>
 402 +#include <linux/netfilter/x_tables.h>
 403 +#ifdef CONFIG_BRIDGE_NETFILTER
 404 +#      include <linux/netfilter_bridge.h>
 405 +#endif
 406 +#include <net/tcp.h>
 407 +#define PFX KBUILD_MODNAME ": "
 408 +
 409 +static void delude_send_reset(struct sk_buff *oldskb, unsigned int hook)
 410 +{
 411 +       struct tcphdr _otcph, *oth, *tcph;
 412 +       unsigned int addr_type;
 413 +       struct sk_buff *nskb;
 414 +       u_int16_t tmp_port;
 415 +       u_int32_t tmp_addr;
 416 +       struct iphdr *niph;
 417 +       bool needs_ack;
 418 +
 419 +       /* IP header checks: fragment. */
 420 +       if (ip_hdr(oldskb)->frag_off & htons(IP_OFFSET))
 421 +               return;
 422 +
 423 +       oth = skb_header_pointer(oldskb, ip_hdrlen(oldskb),
 424 +                                sizeof(_otcph), &_otcph);
 425 +       if (oth == NULL)
 426 +               return;
 427 +
 428 +       /* No RST for RST. */
 429 +       if (oth->rst)
 430 +               return;
 431 +
 432 +       /* Check checksum */
 433 +       if (nf_ip_checksum(oldskb, hook, ip_hdrlen(oldskb), IPPROTO_TCP))
 434 +               return;
 435 +
 436 +       /* We need a linear, writeable skb.  We also need to expand
 437 +          headroom in case hh_len of incoming interface < hh_len of
 438 +          outgoing interface */
 439 +       nskb = skb_copy_expand(oldskb, LL_MAX_HEADER, skb_tailroom(oldskb),
 440 +                              GFP_ATOMIC);
 441 +       if (!nskb)
 442 +               return;
 443 +
 444 +       /* This packet will not be the same as the other: clear nf fields */
 445 +       nf_reset(nskb);
 446 +       nskb->mark = 0;
 447 +       skb_init_secmark(nskb);
 448 +
 449 +       skb_shinfo(nskb)->gso_size = 0;
 450 +       skb_shinfo(nskb)->gso_segs = 0;
 451 +       skb_shinfo(nskb)->gso_type = 0;
 452 +
 453 +       tcph = (struct tcphdr *)(skb_network_header(nskb) + ip_hdrlen(nskb));
 454 +
 455 +       /* Swap source and dest */
 456 +       niph         = ip_hdr(nskb);
 457 +       tmp_addr     = niph->saddr;
 458 +       niph->saddr  = niph->daddr;
 459 +       niph->daddr  = tmp_addr;
 460 +       tmp_port     = tcph->source;
 461 +       tcph->source = tcph->dest;
 462 +       tcph->dest   = tmp_port;
 463 +
 464 +       /* Truncate to length (no data) */
 465 +       tcph->doff    = sizeof(struct tcphdr) / 4;
 466 +       skb_trim(nskb, ip_hdrlen(nskb) + sizeof(struct tcphdr));
 467 +       niph->tot_len = htons(nskb->len);
 468 +
 469 +       if (oth->syn && !oth->ack && !oth->rst && !oth->fin) {
 470 +               /* DELUDE essential part */
 471 +               tcph->ack_seq = htonl(ntohl(oth->seq) + oth->syn + oth->fin +
 472 +                               oldskb->len - ip_hdrlen(oldskb) -
 473 +                               (oth->doff << 2));
 474 +               tcph->seq     = false;
 475 +               tcph->ack     = true;
 476 +       } else {
 477 +               if (!tcph->ack) {
 478 +                       needs_ack     = true;
 479 +                       tcph->ack_seq = htonl(ntohl(oth->seq) + oth->syn +
 480 +                                       oth->fin + oldskb->len -
 481 +                                       ip_hdrlen(oldskb) - (oth->doff<<2));
 482 +                       tcph->seq     = false;
 483 +               } else {
 484 +                       needs_ack     = false;
 485 +                       tcph->seq     = oth->ack_seq;
 486 +                       tcph->ack_seq = false;
 487 +               }
 488 +
 489 +               /* Reset flags */
 490 +               ((u_int8_t *)tcph)[13] = 0;
 491 +               tcph->rst = true;
 492 +               tcph->ack = needs_ack;
 493 +       }
 494 +
 495 +       tcph->window  = 0;
 496 +       tcph->urg_ptr = 0;
 497 +
 498 +       /* Adjust TCP checksum */
 499 +       tcph->check = 0;
 500 +       tcph->check = tcp_v4_check(sizeof(struct tcphdr), niph->saddr,
 501 +                     niph->daddr, csum_partial((char *)tcph,
 502 +                     sizeof(struct tcphdr), 0));
 503 +
 504 +       /* Set DF, id = 0 */
 505 +       niph->frag_off = htons(IP_DF);
 506 +       niph->id       = 0;
 507 +
 508 +       addr_type = RTN_UNSPEC;
 509 +#ifdef CONFIG_BRIDGE_NETFILTER
 510 +       if (hook != NF_IP_FORWARD || (nskb->nf_bridge != NULL &&
 511 +           nskb->nf_bridge->mask & BRNF_BRIDGED))
 512 +#else
 513 +       if (hook != NF_IP_FORWARD)
 514 +#endif
 515 +               addr_type = RTN_LOCAL;
 516 +
 517 +       if (ip_route_me_harder(&nskb, addr_type))
 518 +               goto free_nskb;
 519 +
 520 +       nskb->ip_summed = CHECKSUM_NONE;
 521 +
 522 +       /* Adjust IP TTL */
 523 +       niph->ttl = dst_metric(nskb->dst, RTAX_HOPLIMIT);
 524 +
 525 +       /* Adjust IP checksum */
 526 +       niph->check = 0;
 527 +       niph->check = ip_fast_csum(skb_network_header(nskb), niph->ihl);
 528 +
 529 +       /* "Never happens" */
 530 +       if (nskb->len > dst_mtu(nskb->dst))
 531 +               goto free_nskb;
 532 +
 533 +       nf_ct_attach(nskb, oldskb);
 534 +
 535 +       NF_HOOK(PF_INET, NF_IP_LOCAL_OUT, nskb, NULL, nskb->dst->dev,
 536 +               dst_output);
 537 +       return;
 538 +
 539 + free_nskb:
 540 +       kfree_skb(nskb);
 541 +}
 542 +
 543 +static unsigned int delude_tg(struct sk_buff **pskb,
 544 +    const struct net_device *in, const struct net_device *out,
 545 +    unsigned int hooknum, const struct xt_target *target, const void *targinfo)
 546 +{
 547 +       /* WARNING: This code causes reentry within iptables.
 548 +          This means that the iptables jump stack is now crap.  We
 549 +          must return an absolute verdict. --RR */
 550 +       delude_send_reset(*pskb, hooknum);
 551 +       return NF_DROP;
 552 +}
 553 +
 554 +static struct xt_target delude_tg_reg = {
 555 +       .name       = "DELUDE",
 556 +       .family     = AF_INET,
 557 +       .table      = "filter",
 558 +       .hooks      = (1 << NF_IP_LOCAL_IN) | (1 << NF_IP_FORWARD),
 559 +       .target     = delude_tg,
 560 +       .proto      = IPPROTO_TCP,
 561 +       .me         = THIS_MODULE,
 562 +};
 563 +
 564 +static int __init delude_tg_init(void)
 565 +{
 566 +       return xt_register_target(&delude_tg_reg);
 567 +}
 568 +
 569 +static void __exit delude_tg_exit(void)
 570 +{
 571 +       xt_unregister_target(&delude_tg_reg);
 572 +}
 573 +
 574 +module_init(delude_tg_init);
 575 +module_exit(delude_tg_exit);
 576 +MODULE_AUTHOR("Jan Engelhardt <jengelh@computergmbh.de>");
 577 +MODULE_DESCRIPTION("netfilter \"DELUDE\" target");
 578 +MODULE_LICENSE("GPL");
 579 +MODULE_ALIAS("ipt_DELUDE");
 580 Index: linux-2.6.21.7/net/netfilter/xt_portscan.c
 581 ===================================================================
 582 --- /dev/null
 583 +++ linux-2.6.21.7/net/netfilter/xt_portscan.c
 584 @@ -0,0 +1,269 @@
 585 +/*
 586 + *     portscan match for netfilter
 587 + *     Copyright © CC Computer Consultants GmbH, 2006 - 2007
 588 + *     Contact: Jan Engelhardt <jengelh@computergmbh.de>
 589 + *
 590 + *     This program is free software; you can redistribute it and/or modify
 591 + *     it under the terms of the GNU General Public License; either version
 592 + *     2 or 3 as published by the Free Software Foundation.
 593 + */
 594 +#include <linux/in.h>
 595 +#include <linux/ip.h>
 596 +#include <linux/module.h>
 597 +#include <linux/moduleparam.h>
 598 +#include <linux/skbuff.h>
 599 +#include <linux/stat.h>
 600 +#include <linux/tcp.h>
 601 +#include <linux/types.h>
 602 +#include <linux/version.h>
 603 +#include <linux/netfilter/x_tables.h>
 604 +#include <linux/netfilter/xt_tcpudp.h>
 605 +#include <net/netfilter/nf_nat_rule.h>
 606 +#if defined(_LOCAL)
 607 +#      include "xt_portscan.h"
 608 +#elif defined(CONFIG_NETFILTER_XT_MATCH_PORTSCAN) || \
 609 +    defined(CONFIG_NETFILTER_XT_MATCH_PORTSCAN_MODULE)
 610 +#      include <linux/netfilter/xt_portscan.h>
 611 +#else
 612 +#      include "xt_portscan.h"
 613 +#endif
 614 +#define PFX KBUILD_MODNAME ": "
 615 +
 616 +enum {
 617 +       TCP_FLAGS_ALL3 = TCP_FLAG_FIN | TCP_FLAG_RST | TCP_FLAG_SYN,
 618 +       TCP_FLAGS_ALL4 = TCP_FLAGS_ALL3 | TCP_FLAG_ACK,
 619 +       TCP_FLAGS_ALL6 = TCP_FLAGS_ALL4 | TCP_FLAG_PSH | TCP_FLAG_URG,
 620 +};
 621 +
 622 +/* Module parameters */
 623 +static unsigned int
 624 +       connmark_mask = ~0,
 625 +       packet_mask   = ~0,
 626 +       mark_seen     = 0x9,
 627 +       mark_synrcv   = 0x1,
 628 +       mark_closed   = 0x2,
 629 +       mark_synscan  = 0x3,
 630 +       mark_estab1   = 0x4,
 631 +       mark_estab2   = 0x5,
 632 +       mark_cnscan   = 0x6,
 633 +       mark_grscan   = 0x7,
 634 +       mark_valid    = 0x8;
 635 +
 636 +module_param(connmark_mask, uint, S_IRUGO | S_IWUSR);
 637 +module_param(packet_mask,   uint, S_IRUGO | S_IWUSR);
 638 +module_param(mark_seen,     uint, S_IRUGO | S_IWUSR);
 639 +module_param(mark_synrcv,   uint, S_IRUGO | S_IWUSR);
 640 +module_param(mark_closed,   uint, S_IRUGO | S_IWUSR);
 641 +module_param(mark_synscan,  uint, S_IRUGO | S_IWUSR);
 642 +module_param(mark_estab1,   uint, S_IRUGO | S_IWUSR);
 643 +module_param(mark_estab2,   uint, S_IRUGO | S_IWUSR);
 644 +module_param(mark_cnscan,   uint, S_IRUGO | S_IWUSR);
 645 +module_param(mark_grscan,   uint, S_IRUGO | S_IWUSR);
 646 +module_param(mark_valid,    uint, S_IRUGO | S_IWUSR);
 647 +MODULE_PARM_DESC(connmark_mask, "only set specified bits in connection mark");
 648 +MODULE_PARM_DESC(packet_mask,   "only set specified bits in packet mark");
 649 +MODULE_PARM_DESC(mark_seen,     "nfmark value for packet-seen state");
 650 +MODULE_PARM_DESC(mark_synrcv,   "connmark value for SYN Received state");
 651 +MODULE_PARM_DESC(mark_closed,   "connmark value for closed state");
 652 +MODULE_PARM_DESC(mark_synscan,  "connmark value for SYN Scan state");
 653 +MODULE_PARM_DESC(mark_estab1,   "connmark value for Established-1 state");
 654 +MODULE_PARM_DESC(mark_estab2,   "connmark value for Established-2 state");
 655 +MODULE_PARM_DESC(mark_cnscan,   "connmark value for Connect Scan state");
 656 +MODULE_PARM_DESC(mark_grscan,   "connmark value for Grab Scan state");
 657 +MODULE_PARM_DESC(mark_valid,    "connmark value for Valid state");
 658 +
 659 +/* TCP flag functions */
 660 +static inline bool tflg_ack4(const struct tcphdr *th)
 661 +{
 662 +       return (tcp_flag_word(th) & TCP_FLAGS_ALL4) == TCP_FLAG_ACK;
 663 +}
 664 +
 665 +static inline bool tflg_ack6(const struct tcphdr *th)
 666 +{
 667 +       return (tcp_flag_word(th) & TCP_FLAGS_ALL6) == TCP_FLAG_ACK;
 668 +}
 669 +
 670 +static inline bool tflg_fin(const struct tcphdr *th)
 671 +{
 672 +       return (tcp_flag_word(th) & TCP_FLAGS_ALL3) == TCP_FLAG_FIN;
 673 +}
 674 +
 675 +static inline bool tflg_rst(const struct tcphdr *th)
 676 +{
 677 +       return (tcp_flag_word(th) & TCP_FLAGS_ALL3) == TCP_FLAG_RST;
 678 +}
 679 +
 680 +static inline bool tflg_rstack(const struct tcphdr *th)
 681 +{
 682 +       return (tcp_flag_word(th) & TCP_FLAGS_ALL4) ==
 683 +              (TCP_FLAG_ACK | TCP_FLAG_RST);
 684 +}
 685 +
 686 +static inline bool tflg_syn(const struct tcphdr *th)
 687 +{
 688 +       return (tcp_flag_word(th) & TCP_FLAGS_ALL4) == TCP_FLAG_SYN;
 689 +}
 690 +
 691 +static inline bool tflg_synack(const struct tcphdr *th)
 692 +{
 693 +       return (tcp_flag_word(th) & TCP_FLAGS_ALL4) ==
 694 +              (TCP_FLAG_SYN | TCP_FLAG_ACK);
 695 +}
 696 +
 697 +/* portscan functions */
 698 +static inline bool portscan_mt_stealth(const struct tcphdr *th)
 699 +{
 700 +       /*
 701 +        * "Connection refused" replies to our own probes must not be matched.
 702 +        */
 703 +       if (tflg_rstack(th))
 704 +               return false;
 705 +
 706 +       if (tflg_rst(th) && printk_ratelimit()) {
 707 +               printk(KERN_WARNING PFX "Warning: Pure RST received\n");
 708 +               return false;
 709 +       }
 710 +
 711 +       /*
 712 +        * -p tcp ! --syn -m conntrack --ctstate INVALID: Looking for non-start
 713 +        * packets that are not associated with any connection -- this will
 714 +        * match most scan types (NULL, XMAS, FIN) and ridiculous flag
 715 +        * combinations (SYN-RST, SYN-FIN, SYN-FIN-RST, FIN-RST, etc.).
 716 +        */
 717 +       return !tflg_syn(th);
 718 +}
 719 +
 720 +static inline unsigned int portscan_mt_full(int mark,
 721 +    enum ip_conntrack_info ctstate, bool loopback, const struct tcphdr *tcph,
 722 +    unsigned int payload_len)
 723 +{
 724 +       if (mark == mark_estab2) {
 725 +               /*
 726 +                * -m connmark --mark $ESTAB2
 727 +                */
 728 +               if (tflg_ack4(tcph) && payload_len == 0)
 729 +                       return mark; /* keep mark */
 730 +               else if (tflg_rst(tcph) || tflg_fin(tcph))
 731 +                       return mark_grscan;
 732 +               else
 733 +                       return mark_valid;
 734 +       } else if (mark == mark_estab1) {
 735 +               /*
 736 +                * -m connmark --mark $ESTAB1
 737 +                */
 738 +               if (tflg_rst(tcph) || tflg_fin(tcph))
 739 +                       return mark_cnscan;
 740 +               else if (!loopback && tflg_ack4(tcph) && payload_len == 0)
 741 +                       return mark_estab2;
 742 +               else
 743 +                       return mark_valid;
 744 +       } else if (mark == mark_synrcv) {
 745 +               /*
 746 +                * -m connmark --mark $SYN
 747 +                */
 748 +               if (loopback && tflg_synack(tcph))
 749 +                       return mark; /* keep mark */
 750 +               else if (loopback && tflg_rstack(tcph))
 751 +                       return mark_closed;
 752 +               else if (tflg_ack6(tcph))
 753 +                       return mark_estab1;
 754 +               else
 755 +                       return mark_synscan;
 756 +       } else if (ctstate == IP_CT_NEW && tflg_syn(tcph)) {
 757 +               /*
 758 +                * -p tcp --syn --ctstate NEW
 759 +                */
 760 +               return mark_synrcv;
 761 +       }
 762 +       return mark;
 763 +}
 764 +
 765 +static int portscan_mt(const struct sk_buff *skb,
 766 +    const struct net_device *in, const struct net_device *out,
 767 +    const struct xt_match *match, const void *matchinfo, int offset,
 768 +    unsigned int protoff, int *hotdrop)
 769 +{
 770 +       const struct xt_portscan_match_info *info = matchinfo;
 771 +       enum ip_conntrack_info ctstate;
 772 +       const struct tcphdr *tcph;
 773 +       struct nf_conn *ctdata;
 774 +       struct tcphdr tcph_buf;
 775 +
 776 +       tcph = skb_header_pointer(skb, protoff, sizeof(tcph_buf), &tcph_buf);
 777 +       if (tcph == NULL)
 778 +               return false;
 779 +
 780 +       /* Check for invalid packets: -m conntrack --ctstate INVALID */
 781 +       if ((ctdata = nf_ct_get(skb, &ctstate)) == NULL) {
 782 +               if (info->match_stealth)
 783 +                       return portscan_mt_stealth(tcph);
 784 +               /*
 785 +                * If @ctdata is NULL, we cannot match the other scan
 786 +                * types, return.
 787 +                */
 788 +               return false;
 789 +       }
 790 +
 791 +       /*
 792 +        * If -m portscan was previously applied to this packet, the rules we
 793 +        * simulate must not be run through again. And for speedup, do not call
 794 +        * it either when the connection is already VALID.
 795 +        */
 796 +       if ((ctdata->mark & connmark_mask) == mark_valid ||
 797 +            (skb->mark & packet_mask) != mark_seen) {
 798 +               unsigned int n;
 799 +
 800 +               n = portscan_mt_full(ctdata->mark & connmark_mask, ctstate,
 801 +                   in == &loopback_dev, tcph,
 802 +                   skb->len - protoff - 4 * tcph->doff);
 803 +
 804 +               ctdata->mark = (ctdata->mark & ~connmark_mask) | n;
 805 +               ((struct sk_buff *)skb)->mark =
 806 +                       (skb->mark & ~packet_mask) ^ mark_seen;
 807 +       }
 808 +
 809 +       return (info->match_syn && ctdata->mark == mark_synscan) ||
 810 +              (info->match_cn && ctdata->mark == mark_cnscan) ||
 811 +              (info->match_gr && ctdata->mark == mark_grscan);
 812 +}
 813 +
 814 +static int portscan_mt_check(const char *tablename, const void *entry,
 815 +    const struct xt_match *match, void *matchinfo, unsigned int hook_mask)
 816 +{
 817 +       const struct xt_portscan_match_info *info = matchinfo;
 818 +
 819 +       if ((info->match_stealth & ~1) || (info->match_syn & ~1) ||
 820 +           (info->match_cn & ~1) || (info->match_gr & ~1)) {
 821 +               printk(KERN_WARNING PFX "Invalid flags\n");
 822 +               return false;
 823 +       }
 824 +       return true;
 825 +}
 826 +
 827 +static struct xt_match portscan_mt_reg __read_mostly = {
 828 +       .name       = "portscan",
 829 +       .family     = AF_INET,
 830 +       .match      = portscan_mt,
 831 +       .checkentry = portscan_mt_check,
 832 +       .matchsize  = sizeof(struct xt_portscan_match_info),
 833 +       .proto      = IPPROTO_TCP,
 834 +       .me         = THIS_MODULE,
 835 +};
 836 +
 837 +static int __init portscan_mt_init(void)
 838 +{
 839 +       return xt_register_match(&portscan_mt_reg);
 840 +}
 841 +
 842 +static void __exit portscan_mt_exit(void)
 843 +{
 844 +       xt_unregister_match(&portscan_mt_reg);
 845 +       return;
 846 +}
 847 +
 848 +module_init(portscan_mt_init);
 849 +module_exit(portscan_mt_exit);
 850 +MODULE_AUTHOR("Jan Engelhardt <jengelh@computergmbh.de>");
 851 +MODULE_DESCRIPTION("netfilter \"portscan\" match");
 852 +MODULE_LICENSE("GPL");
 853 +MODULE_ALIAS("ipt_portscan");