1 /* 2 * Copyright (c) 2010 Patrick McHardy <kaber@trash.net> 3 * 4 * This program is free software; you can redistribute it and/or modify 5 * it under the terms of the GNU General Public License version 2 as 6 * published by the Free Software Foundation. 7 */ 8 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 9 #include <linux/module.h> 10 #include <linux/gfp.h> 11 #include <linux/skbuff.h> 12 #include <linux/netfilter_ipv4/ip_tables.h> 13 #include <linux/netfilter_ipv6/ip6_tables.h> 14 #include <linux/netfilter/x_tables.h> 15 #include <linux/netfilter/xt_CT.h> 16 #include <net/netfilter/nf_conntrack.h> 17 #include <net/netfilter/nf_conntrack_l4proto.h> 18 #include <net/netfilter/nf_conntrack_helper.h> 19 #include <net/netfilter/nf_conntrack_ecache.h> 20 #include <net/netfilter/nf_conntrack_timeout.h> 21 #include <net/netfilter/nf_conntrack_zones.h> 22 23 static inline int xt_ct_target(struct sk_buff *skb, struct nf_conn *ct) 24 { 25 /* Previously seen (loopback)? Ignore. */ 26 if (skb->_nfct != 0) 27 return XT_CONTINUE; 28 29 if (ct) { 30 atomic_inc(&ct->ct_general.use); 31 nf_ct_set(skb, ct, IP_CT_NEW); 32 } else { 33 nf_ct_set(skb, ct, IP_CT_UNTRACKED); 34 } 35 36 return XT_CONTINUE; 37 } 38 39 static unsigned int xt_ct_target_v0(struct sk_buff *skb, 40 const struct xt_action_param *par) 41 { 42 const struct xt_ct_target_info *info = par->targinfo; 43 struct nf_conn *ct = info->ct; 44 45 return xt_ct_target(skb, ct); 46 } 47 48 static unsigned int xt_ct_target_v1(struct sk_buff *skb, 49 const struct xt_action_param *par) 50 { 51 const struct xt_ct_target_info_v1 *info = par->targinfo; 52 struct nf_conn *ct = info->ct; 53 54 return xt_ct_target(skb, ct); 55 } 56 57 static u8 xt_ct_find_proto(const struct xt_tgchk_param *par) 58 { 59 if (par->family == NFPROTO_IPV4) { 60 const struct ipt_entry *e = par->entryinfo; 61 62 if (e->ip.invflags & IPT_INV_PROTO) 63 return 0; 64 return e->ip.proto; 65 } else if (par->family == NFPROTO_IPV6) { 66 const struct ip6t_entry *e = par->entryinfo; 67 68 if (e->ipv6.invflags & IP6T_INV_PROTO) 69 return 0; 70 return e->ipv6.proto; 71 } else 72 return 0; 73 } 74 75 static int 76 xt_ct_set_helper(struct nf_conn *ct, const char *helper_name, 77 const struct xt_tgchk_param *par) 78 { 79 struct nf_conntrack_helper *helper; 80 struct nf_conn_help *help; 81 u8 proto; 82 83 proto = xt_ct_find_proto(par); 84 if (!proto) { 85 pr_info_ratelimited("You must specify a L4 protocol and not use inversions on it\n"); 86 return -ENOENT; 87 } 88 89 helper = nf_conntrack_helper_try_module_get(helper_name, par->family, 90 proto); 91 if (helper == NULL) { 92 pr_info_ratelimited("No such helper \"%s\"\n", helper_name); 93 return -ENOENT; 94 } 95 96 help = nf_ct_helper_ext_add(ct, GFP_KERNEL); 97 if (help == NULL) { 98 nf_conntrack_helper_put(helper); 99 return -ENOMEM; 100 } 101 102 help->helper = helper; 103 return 0; 104 } 105 106 #ifdef CONFIG_NF_CONNTRACK_TIMEOUT 107 static void __xt_ct_tg_timeout_put(struct nf_ct_timeout *timeout) 108 { 109 typeof(nf_ct_timeout_put_hook) timeout_put; 110 111 timeout_put = rcu_dereference(nf_ct_timeout_put_hook); 112 if (timeout_put) 113 timeout_put(timeout); 114 } 115 #endif 116 117 static int 118 xt_ct_set_timeout(struct nf_conn *ct, const struct xt_tgchk_param *par, 119 const char *timeout_name) 120 { 121 #ifdef CONFIG_NF_CONNTRACK_TIMEOUT 122 typeof(nf_ct_timeout_find_get_hook) timeout_find_get; 123 const struct nf_conntrack_l4proto *l4proto; 124 struct nf_ct_timeout *timeout; 125 struct nf_conn_timeout *timeout_ext; 126 const char *errmsg = NULL; 127 int ret = 0; 128 u8 proto; 129 130 rcu_read_lock(); 131 timeout_find_get = rcu_dereference(nf_ct_timeout_find_get_hook); 132 if (timeout_find_get == NULL) { 133 ret = -ENOENT; 134 errmsg = "Timeout policy base is empty"; 135 goto out; 136 } 137 138 proto = xt_ct_find_proto(par); 139 if (!proto) { 140 ret = -EINVAL; 141 errmsg = "You must specify a L4 protocol and not use inversions on it"; 142 goto out; 143 } 144 145 timeout = timeout_find_get(par->net, timeout_name); 146 if (timeout == NULL) { 147 ret = -ENOENT; 148 pr_info_ratelimited("No such timeout policy \"%s\"\n", 149 timeout_name); 150 goto out; 151 } 152 153 if (timeout->l3num != par->family) { 154 ret = -EINVAL; 155 pr_info_ratelimited("Timeout policy `%s' can only be used by L%d protocol number %d\n", 156 timeout_name, 3, timeout->l3num); 157 goto err_put_timeout; 158 } 159 /* Make sure the timeout policy matches any existing protocol tracker, 160 * otherwise default to generic. 161 */ 162 l4proto = __nf_ct_l4proto_find(proto); 163 if (timeout->l4proto->l4proto != l4proto->l4proto) { 164 ret = -EINVAL; 165 pr_info_ratelimited("Timeout policy `%s' can only be used by L%d protocol number %d\n", 166 timeout_name, 4, timeout->l4proto->l4proto); 167 goto err_put_timeout; 168 } 169 timeout_ext = nf_ct_timeout_ext_add(ct, timeout, GFP_ATOMIC); 170 if (!timeout_ext) { 171 ret = -ENOMEM; 172 goto err_put_timeout; 173 } 174 175 rcu_read_unlock(); 176 return ret; 177 178 err_put_timeout: 179 __xt_ct_tg_timeout_put(timeout); 180 out: 181 rcu_read_unlock(); 182 if (errmsg) 183 pr_info_ratelimited("%s\n", errmsg); 184 return ret; 185 #else 186 return -EOPNOTSUPP; 187 #endif 188 } 189 190 static u16 xt_ct_flags_to_dir(const struct xt_ct_target_info_v1 *info) 191 { 192 switch (info->flags & (XT_CT_ZONE_DIR_ORIG | 193 XT_CT_ZONE_DIR_REPL)) { 194 case XT_CT_ZONE_DIR_ORIG: 195 return NF_CT_ZONE_DIR_ORIG; 196 case XT_CT_ZONE_DIR_REPL: 197 return NF_CT_ZONE_DIR_REPL; 198 default: 199 return NF_CT_DEFAULT_ZONE_DIR; 200 } 201 } 202 203 static int xt_ct_tg_check(const struct xt_tgchk_param *par, 204 struct xt_ct_target_info_v1 *info) 205 { 206 struct nf_conntrack_zone zone; 207 struct nf_conn_help *help; 208 struct nf_conn *ct; 209 int ret = -EOPNOTSUPP; 210 211 if (info->flags & XT_CT_NOTRACK) { 212 ct = NULL; 213 goto out; 214 } 215 216 #ifndef CONFIG_NF_CONNTRACK_ZONES 217 if (info->zone || info->flags & (XT_CT_ZONE_DIR_ORIG | 218 XT_CT_ZONE_DIR_REPL | 219 XT_CT_ZONE_MARK)) 220 goto err1; 221 #endif 222 223 ret = nf_ct_netns_get(par->net, par->family); 224 if (ret < 0) 225 goto err1; 226 227 memset(&zone, 0, sizeof(zone)); 228 zone.id = info->zone; 229 zone.dir = xt_ct_flags_to_dir(info); 230 if (info->flags & XT_CT_ZONE_MARK) 231 zone.flags |= NF_CT_FLAG_MARK; 232 233 ct = nf_ct_tmpl_alloc(par->net, &zone, GFP_KERNEL); 234 if (!ct) { 235 ret = -ENOMEM; 236 goto err2; 237 } 238 239 ret = 0; 240 if ((info->ct_events || info->exp_events) && 241 !nf_ct_ecache_ext_add(ct, info->ct_events, info->exp_events, 242 GFP_KERNEL)) { 243 ret = -EINVAL; 244 goto err3; 245 } 246 247 if (info->helper[0]) { 248 if (strnlen(info->helper, sizeof(info->helper)) == sizeof(info->helper)) { 249 ret = -ENAMETOOLONG; 250 goto err3; 251 } 252 253 ret = xt_ct_set_helper(ct, info->helper, par); 254 if (ret < 0) 255 goto err3; 256 } 257 258 if (info->timeout[0]) { 259 if (strnlen(info->timeout, sizeof(info->timeout)) == sizeof(info->timeout)) { 260 ret = -ENAMETOOLONG; 261 goto err4; 262 } 263 264 ret = xt_ct_set_timeout(ct, par, info->timeout); 265 if (ret < 0) 266 goto err4; 267 } 268 __set_bit(IPS_CONFIRMED_BIT, &ct->status); 269 nf_conntrack_get(&ct->ct_general); 270 out: 271 info->ct = ct; 272 return 0; 273 274 err4: 275 help = nfct_help(ct); 276 if (help) 277 nf_conntrack_helper_put(help->helper); 278 err3: 279 nf_ct_tmpl_free(ct); 280 err2: 281 nf_ct_netns_put(par->net, par->family); 282 err1: 283 return ret; 284 } 285 286 static int xt_ct_tg_check_v0(const struct xt_tgchk_param *par) 287 { 288 struct xt_ct_target_info *info = par->targinfo; 289 struct xt_ct_target_info_v1 info_v1 = { 290 .flags = info->flags, 291 .zone = info->zone, 292 .ct_events = info->ct_events, 293 .exp_events = info->exp_events, 294 }; 295 int ret; 296 297 if (info->flags & ~XT_CT_NOTRACK) 298 return -EINVAL; 299 300 memcpy(info_v1.helper, info->helper, sizeof(info->helper)); 301 302 ret = xt_ct_tg_check(par, &info_v1); 303 if (ret < 0) 304 return ret; 305 306 info->ct = info_v1.ct; 307 308 return ret; 309 } 310 311 static int xt_ct_tg_check_v1(const struct xt_tgchk_param *par) 312 { 313 struct xt_ct_target_info_v1 *info = par->targinfo; 314 315 if (info->flags & ~XT_CT_NOTRACK) 316 return -EINVAL; 317 318 return xt_ct_tg_check(par, par->targinfo); 319 } 320 321 static int xt_ct_tg_check_v2(const struct xt_tgchk_param *par) 322 { 323 struct xt_ct_target_info_v1 *info = par->targinfo; 324 325 if (info->flags & ~XT_CT_MASK) 326 return -EINVAL; 327 328 return xt_ct_tg_check(par, par->targinfo); 329 } 330 331 static void xt_ct_destroy_timeout(struct nf_conn *ct) 332 { 333 #ifdef CONFIG_NF_CONNTRACK_TIMEOUT 334 struct nf_conn_timeout *timeout_ext; 335 typeof(nf_ct_timeout_put_hook) timeout_put; 336 337 rcu_read_lock(); 338 timeout_put = rcu_dereference(nf_ct_timeout_put_hook); 339 340 if (timeout_put) { 341 timeout_ext = nf_ct_timeout_find(ct); 342 if (timeout_ext) { 343 timeout_put(timeout_ext->timeout); 344 RCU_INIT_POINTER(timeout_ext->timeout, NULL); 345 } 346 } 347 rcu_read_unlock(); 348 #endif 349 } 350 351 static void xt_ct_tg_destroy(const struct xt_tgdtor_param *par, 352 struct xt_ct_target_info_v1 *info) 353 { 354 struct nf_conn *ct = info->ct; 355 struct nf_conn_help *help; 356 357 if (ct) { 358 help = nfct_help(ct); 359 if (help) 360 nf_conntrack_helper_put(help->helper); 361 362 nf_ct_netns_put(par->net, par->family); 363 364 xt_ct_destroy_timeout(ct); 365 nf_ct_put(info->ct); 366 } 367 } 368 369 static void xt_ct_tg_destroy_v0(const struct xt_tgdtor_param *par) 370 { 371 struct xt_ct_target_info *info = par->targinfo; 372 struct xt_ct_target_info_v1 info_v1 = { 373 .flags = info->flags, 374 .zone = info->zone, 375 .ct_events = info->ct_events, 376 .exp_events = info->exp_events, 377 .ct = info->ct, 378 }; 379 memcpy(info_v1.helper, info->helper, sizeof(info->helper)); 380 381 xt_ct_tg_destroy(par, &info_v1); 382 } 383 384 static void xt_ct_tg_destroy_v1(const struct xt_tgdtor_param *par) 385 { 386 xt_ct_tg_destroy(par, par->targinfo); 387 } 388 389 static struct xt_target xt_ct_tg_reg[] __read_mostly = { 390 { 391 .name = "CT", 392 .family = NFPROTO_UNSPEC, 393 .targetsize = sizeof(struct xt_ct_target_info), 394 .usersize = offsetof(struct xt_ct_target_info, ct), 395 .checkentry = xt_ct_tg_check_v0, 396 .destroy = xt_ct_tg_destroy_v0, 397 .target = xt_ct_target_v0, 398 .table = "raw", 399 .me = THIS_MODULE, 400 }, 401 { 402 .name = "CT", 403 .family = NFPROTO_UNSPEC, 404 .revision = 1, 405 .targetsize = sizeof(struct xt_ct_target_info_v1), 406 .usersize = offsetof(struct xt_ct_target_info, ct), 407 .checkentry = xt_ct_tg_check_v1, 408 .destroy = xt_ct_tg_destroy_v1, 409 .target = xt_ct_target_v1, 410 .table = "raw", 411 .me = THIS_MODULE, 412 }, 413 { 414 .name = "CT", 415 .family = NFPROTO_UNSPEC, 416 .revision = 2, 417 .targetsize = sizeof(struct xt_ct_target_info_v1), 418 .usersize = offsetof(struct xt_ct_target_info, ct), 419 .checkentry = xt_ct_tg_check_v2, 420 .destroy = xt_ct_tg_destroy_v1, 421 .target = xt_ct_target_v1, 422 .table = "raw", 423 .me = THIS_MODULE, 424 }, 425 }; 426 427 static unsigned int 428 notrack_tg(struct sk_buff *skb, const struct xt_action_param *par) 429 { 430 /* Previously seen (loopback)? Ignore. */ 431 if (skb->_nfct != 0) 432 return XT_CONTINUE; 433 434 nf_ct_set(skb, NULL, IP_CT_UNTRACKED); 435 436 return XT_CONTINUE; 437 } 438 439 static int notrack_chk(const struct xt_tgchk_param *par) 440 { 441 if (!par->net->xt.notrack_deprecated_warning) { 442 pr_info("netfilter: NOTRACK target is deprecated, " 443 "use CT instead or upgrade iptables\n"); 444 par->net->xt.notrack_deprecated_warning = true; 445 } 446 return 0; 447 } 448 449 static struct xt_target notrack_tg_reg __read_mostly = { 450 .name = "NOTRACK", 451 .revision = 0, 452 .family = NFPROTO_UNSPEC, 453 .checkentry = notrack_chk, 454 .target = notrack_tg, 455 .table = "raw", 456 .me = THIS_MODULE, 457 }; 458 459 static int __init xt_ct_tg_init(void) 460 { 461 int ret; 462 463 ret = xt_register_target(¬rack_tg_reg); 464 if (ret < 0) 465 return ret; 466 467 ret = xt_register_targets(xt_ct_tg_reg, ARRAY_SIZE(xt_ct_tg_reg)); 468 if (ret < 0) { 469 xt_unregister_target(¬rack_tg_reg); 470 return ret; 471 } 472 return 0; 473 } 474 475 static void __exit xt_ct_tg_exit(void) 476 { 477 xt_unregister_targets(xt_ct_tg_reg, ARRAY_SIZE(xt_ct_tg_reg)); 478 xt_unregister_target(¬rack_tg_reg); 479 } 480 481 module_init(xt_ct_tg_init); 482 module_exit(xt_ct_tg_exit); 483 484 MODULE_LICENSE("GPL"); 485 MODULE_DESCRIPTION("Xtables: connection tracking target"); 486 MODULE_ALIAS("ipt_CT"); 487 MODULE_ALIAS("ip6t_CT"); 488 MODULE_ALIAS("ipt_NOTRACK"); 489 MODULE_ALIAS("ip6t_NOTRACK"); 490