target/linux/generic-2.6/patches-2.6.21/170-netfilter_chaostables_0.8.patch

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