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("You must specify a L4 protocol, and not use " 86 "inversions on it.\n"); 87 return -ENOENT; 88 } 89 90 helper = nf_conntrack_helper_try_module_get(helper_name, par->family, 91 proto); 92 if (helper == NULL) { 93 pr_info("No such helper \"%s\"\n", helper_name); 94 return -ENOENT; 95 } 96 97 help = nf_ct_helper_ext_add(ct, helper, GFP_KERNEL); 98 if (help == NULL) { 99 nf_conntrack_helper_put(helper); 100 return -ENOMEM; 101 } 102 103 help->helper = helper; 104 return 0; 105 } 106 107 #ifdef CONFIG_NF_CONNTRACK_TIMEOUT 108 static void __xt_ct_tg_timeout_put(struct ctnl_timeout *timeout) 109 { 110 typeof(nf_ct_timeout_put_hook) timeout_put; 111 112 timeout_put = rcu_dereference(nf_ct_timeout_put_hook); 113 if (timeout_put) 114 timeout_put(timeout); 115 } 116 #endif 117 118 static int 119 xt_ct_set_timeout(struct nf_conn *ct, const struct xt_tgchk_param *par, 120 const char *timeout_name) 121 { 122 #ifdef CONFIG_NF_CONNTRACK_TIMEOUT 123 typeof(nf_ct_timeout_find_get_hook) timeout_find_get; 124 struct ctnl_timeout *timeout; 125 struct nf_conn_timeout *timeout_ext; 126 struct nf_conntrack_l4proto *l4proto; 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 pr_info("Timeout policy base is empty\n"); 135 goto out; 136 } 137 138 proto = xt_ct_find_proto(par); 139 if (!proto) { 140 ret = -EINVAL; 141 pr_info("You must specify a L4 protocol, and not use " 142 "inversions on it.\n"); 143 goto out; 144 } 145 146 timeout = timeout_find_get(par->net, timeout_name); 147 if (timeout == NULL) { 148 ret = -ENOENT; 149 pr_info("No such timeout policy \"%s\"\n", timeout_name); 150 goto out; 151 } 152 153 if (timeout->l3num != par->family) { 154 ret = -EINVAL; 155 pr_info("Timeout policy `%s' can only be used by L3 protocol " 156 "number %d\n", timeout_name, 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("Timeout policy `%s' can only be used by L4 protocol " 166 "number %d\n", 167 timeout_name, timeout->l4proto->l4proto); 168 goto err_put_timeout; 169 } 170 timeout_ext = nf_ct_timeout_ext_add(ct, timeout, GFP_ATOMIC); 171 if (!timeout_ext) { 172 ret = -ENOMEM; 173 goto err_put_timeout; 174 } 175 176 rcu_read_unlock(); 177 return ret; 178 179 err_put_timeout: 180 __xt_ct_tg_timeout_put(timeout); 181 out: 182 rcu_read_unlock(); 183 return ret; 184 #else 185 return -EOPNOTSUPP; 186 #endif 187 } 188 189 static u16 xt_ct_flags_to_dir(const struct xt_ct_target_info_v1 *info) 190 { 191 switch (info->flags & (XT_CT_ZONE_DIR_ORIG | 192 XT_CT_ZONE_DIR_REPL)) { 193 case XT_CT_ZONE_DIR_ORIG: 194 return NF_CT_ZONE_DIR_ORIG; 195 case XT_CT_ZONE_DIR_REPL: 196 return NF_CT_ZONE_DIR_REPL; 197 default: 198 return NF_CT_DEFAULT_ZONE_DIR; 199 } 200 } 201 202 static int xt_ct_tg_check(const struct xt_tgchk_param *par, 203 struct xt_ct_target_info_v1 *info) 204 { 205 struct nf_conntrack_zone zone; 206 struct nf_conn_help *help; 207 struct nf_conn *ct; 208 int ret = -EOPNOTSUPP; 209 210 if (info->flags & XT_CT_NOTRACK) { 211 ct = NULL; 212 goto out; 213 } 214 215 #ifndef CONFIG_NF_CONNTRACK_ZONES 216 if (info->zone || info->flags & (XT_CT_ZONE_DIR_ORIG | 217 XT_CT_ZONE_DIR_REPL | 218 XT_CT_ZONE_MARK)) 219 goto err1; 220 #endif 221 222 ret = nf_ct_netns_get(par->net, par->family); 223 if (ret < 0) 224 goto err1; 225 226 memset(&zone, 0, sizeof(zone)); 227 zone.id = info->zone; 228 zone.dir = xt_ct_flags_to_dir(info); 229 if (info->flags & XT_CT_ZONE_MARK) 230 zone.flags |= NF_CT_FLAG_MARK; 231 232 ct = nf_ct_tmpl_alloc(par->net, &zone, GFP_KERNEL); 233 if (!ct) { 234 ret = -ENOMEM; 235 goto err2; 236 } 237 238 ret = 0; 239 if ((info->ct_events || info->exp_events) && 240 !nf_ct_ecache_ext_add(ct, info->ct_events, info->exp_events, 241 GFP_KERNEL)) { 242 ret = -EINVAL; 243 goto err3; 244 } 245 246 if (info->helper[0]) { 247 ret = xt_ct_set_helper(ct, info->helper, par); 248 if (ret < 0) 249 goto err3; 250 } 251 252 if (info->timeout[0]) { 253 ret = xt_ct_set_timeout(ct, par, info->timeout); 254 if (ret < 0) 255 goto err4; 256 } 257 __set_bit(IPS_CONFIRMED_BIT, &ct->status); 258 nf_conntrack_get(&ct->ct_general); 259 out: 260 info->ct = ct; 261 return 0; 262 263 err4: 264 help = nfct_help(ct); 265 if (help) 266 nf_conntrack_helper_put(help->helper); 267 err3: 268 nf_ct_tmpl_free(ct); 269 err2: 270 nf_ct_netns_put(par->net, par->family); 271 err1: 272 return ret; 273 } 274 275 static int xt_ct_tg_check_v0(const struct xt_tgchk_param *par) 276 { 277 struct xt_ct_target_info *info = par->targinfo; 278 struct xt_ct_target_info_v1 info_v1 = { 279 .flags = info->flags, 280 .zone = info->zone, 281 .ct_events = info->ct_events, 282 .exp_events = info->exp_events, 283 }; 284 int ret; 285 286 if (info->flags & ~XT_CT_NOTRACK) 287 return -EINVAL; 288 289 memcpy(info_v1.helper, info->helper, sizeof(info->helper)); 290 291 ret = xt_ct_tg_check(par, &info_v1); 292 if (ret < 0) 293 return ret; 294 295 info->ct = info_v1.ct; 296 297 return ret; 298 } 299 300 static int xt_ct_tg_check_v1(const struct xt_tgchk_param *par) 301 { 302 struct xt_ct_target_info_v1 *info = par->targinfo; 303 304 if (info->flags & ~XT_CT_NOTRACK) 305 return -EINVAL; 306 307 return xt_ct_tg_check(par, par->targinfo); 308 } 309 310 static int xt_ct_tg_check_v2(const struct xt_tgchk_param *par) 311 { 312 struct xt_ct_target_info_v1 *info = par->targinfo; 313 314 if (info->flags & ~XT_CT_MASK) 315 return -EINVAL; 316 317 return xt_ct_tg_check(par, par->targinfo); 318 } 319 320 static void xt_ct_destroy_timeout(struct nf_conn *ct) 321 { 322 #ifdef CONFIG_NF_CONNTRACK_TIMEOUT 323 struct nf_conn_timeout *timeout_ext; 324 typeof(nf_ct_timeout_put_hook) timeout_put; 325 326 rcu_read_lock(); 327 timeout_put = rcu_dereference(nf_ct_timeout_put_hook); 328 329 if (timeout_put) { 330 timeout_ext = nf_ct_timeout_find(ct); 331 if (timeout_ext) { 332 timeout_put(timeout_ext->timeout); 333 RCU_INIT_POINTER(timeout_ext->timeout, NULL); 334 } 335 } 336 rcu_read_unlock(); 337 #endif 338 } 339 340 static void xt_ct_tg_destroy(const struct xt_tgdtor_param *par, 341 struct xt_ct_target_info_v1 *info) 342 { 343 struct nf_conn *ct = info->ct; 344 struct nf_conn_help *help; 345 346 if (ct) { 347 help = nfct_help(ct); 348 if (help) 349 nf_conntrack_helper_put(help->helper); 350 351 nf_ct_netns_put(par->net, par->family); 352 353 xt_ct_destroy_timeout(ct); 354 nf_ct_put(info->ct); 355 } 356 } 357 358 static void xt_ct_tg_destroy_v0(const struct xt_tgdtor_param *par) 359 { 360 struct xt_ct_target_info *info = par->targinfo; 361 struct xt_ct_target_info_v1 info_v1 = { 362 .flags = info->flags, 363 .zone = info->zone, 364 .ct_events = info->ct_events, 365 .exp_events = info->exp_events, 366 .ct = info->ct, 367 }; 368 memcpy(info_v1.helper, info->helper, sizeof(info->helper)); 369 370 xt_ct_tg_destroy(par, &info_v1); 371 } 372 373 static void xt_ct_tg_destroy_v1(const struct xt_tgdtor_param *par) 374 { 375 xt_ct_tg_destroy(par, par->targinfo); 376 } 377 378 static struct xt_target xt_ct_tg_reg[] __read_mostly = { 379 { 380 .name = "CT", 381 .family = NFPROTO_UNSPEC, 382 .targetsize = sizeof(struct xt_ct_target_info), 383 .usersize = offsetof(struct xt_ct_target_info, ct), 384 .checkentry = xt_ct_tg_check_v0, 385 .destroy = xt_ct_tg_destroy_v0, 386 .target = xt_ct_target_v0, 387 .table = "raw", 388 .me = THIS_MODULE, 389 }, 390 { 391 .name = "CT", 392 .family = NFPROTO_UNSPEC, 393 .revision = 1, 394 .targetsize = sizeof(struct xt_ct_target_info_v1), 395 .usersize = offsetof(struct xt_ct_target_info, ct), 396 .checkentry = xt_ct_tg_check_v1, 397 .destroy = xt_ct_tg_destroy_v1, 398 .target = xt_ct_target_v1, 399 .table = "raw", 400 .me = THIS_MODULE, 401 }, 402 { 403 .name = "CT", 404 .family = NFPROTO_UNSPEC, 405 .revision = 2, 406 .targetsize = sizeof(struct xt_ct_target_info_v1), 407 .usersize = offsetof(struct xt_ct_target_info, ct), 408 .checkentry = xt_ct_tg_check_v2, 409 .destroy = xt_ct_tg_destroy_v1, 410 .target = xt_ct_target_v1, 411 .table = "raw", 412 .me = THIS_MODULE, 413 }, 414 }; 415 416 static unsigned int 417 notrack_tg(struct sk_buff *skb, const struct xt_action_param *par) 418 { 419 /* Previously seen (loopback)? Ignore. */ 420 if (skb->_nfct != 0) 421 return XT_CONTINUE; 422 423 nf_ct_set(skb, NULL, IP_CT_UNTRACKED); 424 425 return XT_CONTINUE; 426 } 427 428 static int notrack_chk(const struct xt_tgchk_param *par) 429 { 430 if (!par->net->xt.notrack_deprecated_warning) { 431 pr_info("netfilter: NOTRACK target is deprecated, " 432 "use CT instead or upgrade iptables\n"); 433 par->net->xt.notrack_deprecated_warning = true; 434 } 435 return 0; 436 } 437 438 static struct xt_target notrack_tg_reg __read_mostly = { 439 .name = "NOTRACK", 440 .revision = 0, 441 .family = NFPROTO_UNSPEC, 442 .checkentry = notrack_chk, 443 .target = notrack_tg, 444 .table = "raw", 445 .me = THIS_MODULE, 446 }; 447 448 static int __init xt_ct_tg_init(void) 449 { 450 int ret; 451 452 ret = xt_register_target(¬rack_tg_reg); 453 if (ret < 0) 454 return ret; 455 456 ret = xt_register_targets(xt_ct_tg_reg, ARRAY_SIZE(xt_ct_tg_reg)); 457 if (ret < 0) { 458 xt_unregister_target(¬rack_tg_reg); 459 return ret; 460 } 461 return 0; 462 } 463 464 static void __exit xt_ct_tg_exit(void) 465 { 466 xt_unregister_targets(xt_ct_tg_reg, ARRAY_SIZE(xt_ct_tg_reg)); 467 xt_unregister_target(¬rack_tg_reg); 468 } 469 470 module_init(xt_ct_tg_init); 471 module_exit(xt_ct_tg_exit); 472 473 MODULE_LICENSE("GPL"); 474 MODULE_DESCRIPTION("Xtables: connection tracking target"); 475 MODULE_ALIAS("ipt_CT"); 476 MODULE_ALIAS("ip6t_CT"); 477 MODULE_ALIAS("ipt_NOTRACK"); 478 MODULE_ALIAS("ip6t_NOTRACK"); 479