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, helper, 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 ctnl_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 ctnl_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(par->family, 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 ret = xt_ct_set_helper(ct, info->helper, par); 249 if (ret < 0) 250 goto err3; 251 } 252 253 if (info->timeout[0]) { 254 ret = xt_ct_set_timeout(ct, par, info->timeout); 255 if (ret < 0) 256 goto err4; 257 } 258 __set_bit(IPS_CONFIRMED_BIT, &ct->status); 259 nf_conntrack_get(&ct->ct_general); 260 out: 261 info->ct = ct; 262 return 0; 263 264 err4: 265 help = nfct_help(ct); 266 if (help) 267 nf_conntrack_helper_put(help->helper); 268 err3: 269 nf_ct_tmpl_free(ct); 270 err2: 271 nf_ct_netns_put(par->net, par->family); 272 err1: 273 return ret; 274 } 275 276 static int xt_ct_tg_check_v0(const struct xt_tgchk_param *par) 277 { 278 struct xt_ct_target_info *info = par->targinfo; 279 struct xt_ct_target_info_v1 info_v1 = { 280 .flags = info->flags, 281 .zone = info->zone, 282 .ct_events = info->ct_events, 283 .exp_events = info->exp_events, 284 }; 285 int ret; 286 287 if (info->flags & ~XT_CT_NOTRACK) 288 return -EINVAL; 289 290 memcpy(info_v1.helper, info->helper, sizeof(info->helper)); 291 292 ret = xt_ct_tg_check(par, &info_v1); 293 if (ret < 0) 294 return ret; 295 296 info->ct = info_v1.ct; 297 298 return ret; 299 } 300 301 static int xt_ct_tg_check_v1(const struct xt_tgchk_param *par) 302 { 303 struct xt_ct_target_info_v1 *info = par->targinfo; 304 305 if (info->flags & ~XT_CT_NOTRACK) 306 return -EINVAL; 307 308 return xt_ct_tg_check(par, par->targinfo); 309 } 310 311 static int xt_ct_tg_check_v2(const struct xt_tgchk_param *par) 312 { 313 struct xt_ct_target_info_v1 *info = par->targinfo; 314 315 if (info->flags & ~XT_CT_MASK) 316 return -EINVAL; 317 318 return xt_ct_tg_check(par, par->targinfo); 319 } 320 321 static void xt_ct_destroy_timeout(struct nf_conn *ct) 322 { 323 #ifdef CONFIG_NF_CONNTRACK_TIMEOUT 324 struct nf_conn_timeout *timeout_ext; 325 typeof(nf_ct_timeout_put_hook) timeout_put; 326 327 rcu_read_lock(); 328 timeout_put = rcu_dereference(nf_ct_timeout_put_hook); 329 330 if (timeout_put) { 331 timeout_ext = nf_ct_timeout_find(ct); 332 if (timeout_ext) { 333 timeout_put(timeout_ext->timeout); 334 RCU_INIT_POINTER(timeout_ext->timeout, NULL); 335 } 336 } 337 rcu_read_unlock(); 338 #endif 339 } 340 341 static void xt_ct_tg_destroy(const struct xt_tgdtor_param *par, 342 struct xt_ct_target_info_v1 *info) 343 { 344 struct nf_conn *ct = info->ct; 345 struct nf_conn_help *help; 346 347 if (ct) { 348 help = nfct_help(ct); 349 if (help) 350 nf_conntrack_helper_put(help->helper); 351 352 nf_ct_netns_put(par->net, par->family); 353 354 xt_ct_destroy_timeout(ct); 355 nf_ct_put(info->ct); 356 } 357 } 358 359 static void xt_ct_tg_destroy_v0(const struct xt_tgdtor_param *par) 360 { 361 struct xt_ct_target_info *info = par->targinfo; 362 struct xt_ct_target_info_v1 info_v1 = { 363 .flags = info->flags, 364 .zone = info->zone, 365 .ct_events = info->ct_events, 366 .exp_events = info->exp_events, 367 .ct = info->ct, 368 }; 369 memcpy(info_v1.helper, info->helper, sizeof(info->helper)); 370 371 xt_ct_tg_destroy(par, &info_v1); 372 } 373 374 static void xt_ct_tg_destroy_v1(const struct xt_tgdtor_param *par) 375 { 376 xt_ct_tg_destroy(par, par->targinfo); 377 } 378 379 static struct xt_target xt_ct_tg_reg[] __read_mostly = { 380 { 381 .name = "CT", 382 .family = NFPROTO_UNSPEC, 383 .targetsize = sizeof(struct xt_ct_target_info), 384 .usersize = offsetof(struct xt_ct_target_info, ct), 385 .checkentry = xt_ct_tg_check_v0, 386 .destroy = xt_ct_tg_destroy_v0, 387 .target = xt_ct_target_v0, 388 .table = "raw", 389 .me = THIS_MODULE, 390 }, 391 { 392 .name = "CT", 393 .family = NFPROTO_UNSPEC, 394 .revision = 1, 395 .targetsize = sizeof(struct xt_ct_target_info_v1), 396 .usersize = offsetof(struct xt_ct_target_info, ct), 397 .checkentry = xt_ct_tg_check_v1, 398 .destroy = xt_ct_tg_destroy_v1, 399 .target = xt_ct_target_v1, 400 .table = "raw", 401 .me = THIS_MODULE, 402 }, 403 { 404 .name = "CT", 405 .family = NFPROTO_UNSPEC, 406 .revision = 2, 407 .targetsize = sizeof(struct xt_ct_target_info_v1), 408 .usersize = offsetof(struct xt_ct_target_info, ct), 409 .checkentry = xt_ct_tg_check_v2, 410 .destroy = xt_ct_tg_destroy_v1, 411 .target = xt_ct_target_v1, 412 .table = "raw", 413 .me = THIS_MODULE, 414 }, 415 }; 416 417 static unsigned int 418 notrack_tg(struct sk_buff *skb, const struct xt_action_param *par) 419 { 420 /* Previously seen (loopback)? Ignore. */ 421 if (skb->_nfct != 0) 422 return XT_CONTINUE; 423 424 nf_ct_set(skb, NULL, IP_CT_UNTRACKED); 425 426 return XT_CONTINUE; 427 } 428 429 static int notrack_chk(const struct xt_tgchk_param *par) 430 { 431 if (!par->net->xt.notrack_deprecated_warning) { 432 pr_info("netfilter: NOTRACK target is deprecated, " 433 "use CT instead or upgrade iptables\n"); 434 par->net->xt.notrack_deprecated_warning = true; 435 } 436 return 0; 437 } 438 439 static struct xt_target notrack_tg_reg __read_mostly = { 440 .name = "NOTRACK", 441 .revision = 0, 442 .family = NFPROTO_UNSPEC, 443 .checkentry = notrack_chk, 444 .target = notrack_tg, 445 .table = "raw", 446 .me = THIS_MODULE, 447 }; 448 449 static int __init xt_ct_tg_init(void) 450 { 451 int ret; 452 453 ret = xt_register_target(¬rack_tg_reg); 454 if (ret < 0) 455 return ret; 456 457 ret = xt_register_targets(xt_ct_tg_reg, ARRAY_SIZE(xt_ct_tg_reg)); 458 if (ret < 0) { 459 xt_unregister_target(¬rack_tg_reg); 460 return ret; 461 } 462 return 0; 463 } 464 465 static void __exit xt_ct_tg_exit(void) 466 { 467 xt_unregister_targets(xt_ct_tg_reg, ARRAY_SIZE(xt_ct_tg_reg)); 468 xt_unregister_target(¬rack_tg_reg); 469 } 470 471 module_init(xt_ct_tg_init); 472 module_exit(xt_ct_tg_exit); 473 474 MODULE_LICENSE("GPL"); 475 MODULE_DESCRIPTION("Xtables: connection tracking target"); 476 MODULE_ALIAS("ipt_CT"); 477 MODULE_ALIAS("ip6t_CT"); 478 MODULE_ALIAS("ipt_NOTRACK"); 479 MODULE_ALIAS("ip6t_NOTRACK"); 480