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 != NULL) 27 return XT_CONTINUE; 28 29 /* special case the untracked ct : we want the percpu object */ 30 if (!ct) 31 ct = nf_ct_untracked_get(); 32 atomic_inc(&ct->ct_general.use); 33 skb->nfct = &ct->ct_general; 34 skb->nfctinfo = IP_CT_NEW; 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 module_put(helper->me); 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 == NULL) 172 ret = -ENOMEM; 173 174 rcu_read_unlock(); 175 return ret; 176 177 err_put_timeout: 178 __xt_ct_tg_timeout_put(timeout); 179 out: 180 rcu_read_unlock(); 181 return ret; 182 #else 183 return -EOPNOTSUPP; 184 #endif 185 } 186 187 static u16 xt_ct_flags_to_dir(const struct xt_ct_target_info_v1 *info) 188 { 189 switch (info->flags & (XT_CT_ZONE_DIR_ORIG | 190 XT_CT_ZONE_DIR_REPL)) { 191 case XT_CT_ZONE_DIR_ORIG: 192 return NF_CT_ZONE_DIR_ORIG; 193 case XT_CT_ZONE_DIR_REPL: 194 return NF_CT_ZONE_DIR_REPL; 195 default: 196 return NF_CT_DEFAULT_ZONE_DIR; 197 } 198 } 199 200 static int xt_ct_tg_check(const struct xt_tgchk_param *par, 201 struct xt_ct_target_info_v1 *info) 202 { 203 struct nf_conntrack_zone zone; 204 struct nf_conn *ct; 205 int ret = -EOPNOTSUPP; 206 207 if (info->flags & XT_CT_NOTRACK) { 208 ct = NULL; 209 goto out; 210 } 211 212 #ifndef CONFIG_NF_CONNTRACK_ZONES 213 if (info->zone || info->flags & (XT_CT_ZONE_DIR_ORIG | 214 XT_CT_ZONE_DIR_REPL | 215 XT_CT_ZONE_MARK)) 216 goto err1; 217 #endif 218 219 ret = nf_ct_netns_get(par->net, par->family); 220 if (ret < 0) 221 goto err1; 222 223 memset(&zone, 0, sizeof(zone)); 224 zone.id = info->zone; 225 zone.dir = xt_ct_flags_to_dir(info); 226 if (info->flags & XT_CT_ZONE_MARK) 227 zone.flags |= NF_CT_FLAG_MARK; 228 229 ct = nf_ct_tmpl_alloc(par->net, &zone, GFP_KERNEL); 230 if (!ct) { 231 ret = -ENOMEM; 232 goto err2; 233 } 234 235 ret = 0; 236 if ((info->ct_events || info->exp_events) && 237 !nf_ct_ecache_ext_add(ct, info->ct_events, info->exp_events, 238 GFP_KERNEL)) { 239 ret = -EINVAL; 240 goto err3; 241 } 242 243 if (info->helper[0]) { 244 ret = xt_ct_set_helper(ct, info->helper, par); 245 if (ret < 0) 246 goto err3; 247 } 248 249 if (info->timeout[0]) { 250 ret = xt_ct_set_timeout(ct, par, info->timeout); 251 if (ret < 0) 252 goto err3; 253 } 254 __set_bit(IPS_CONFIRMED_BIT, &ct->status); 255 nf_conntrack_get(&ct->ct_general); 256 out: 257 info->ct = ct; 258 return 0; 259 260 err3: 261 nf_ct_tmpl_free(ct); 262 err2: 263 nf_ct_netns_put(par->net, par->family); 264 err1: 265 return ret; 266 } 267 268 static int xt_ct_tg_check_v0(const struct xt_tgchk_param *par) 269 { 270 struct xt_ct_target_info *info = par->targinfo; 271 struct xt_ct_target_info_v1 info_v1 = { 272 .flags = info->flags, 273 .zone = info->zone, 274 .ct_events = info->ct_events, 275 .exp_events = info->exp_events, 276 }; 277 int ret; 278 279 if (info->flags & ~XT_CT_NOTRACK) 280 return -EINVAL; 281 282 memcpy(info_v1.helper, info->helper, sizeof(info->helper)); 283 284 ret = xt_ct_tg_check(par, &info_v1); 285 if (ret < 0) 286 return ret; 287 288 info->ct = info_v1.ct; 289 290 return ret; 291 } 292 293 static int xt_ct_tg_check_v1(const struct xt_tgchk_param *par) 294 { 295 struct xt_ct_target_info_v1 *info = par->targinfo; 296 297 if (info->flags & ~XT_CT_NOTRACK) 298 return -EINVAL; 299 300 return xt_ct_tg_check(par, par->targinfo); 301 } 302 303 static int xt_ct_tg_check_v2(const struct xt_tgchk_param *par) 304 { 305 struct xt_ct_target_info_v1 *info = par->targinfo; 306 307 if (info->flags & ~XT_CT_MASK) 308 return -EINVAL; 309 310 return xt_ct_tg_check(par, par->targinfo); 311 } 312 313 static void xt_ct_destroy_timeout(struct nf_conn *ct) 314 { 315 #ifdef CONFIG_NF_CONNTRACK_TIMEOUT 316 struct nf_conn_timeout *timeout_ext; 317 typeof(nf_ct_timeout_put_hook) timeout_put; 318 319 rcu_read_lock(); 320 timeout_put = rcu_dereference(nf_ct_timeout_put_hook); 321 322 if (timeout_put) { 323 timeout_ext = nf_ct_timeout_find(ct); 324 if (timeout_ext) { 325 timeout_put(timeout_ext->timeout); 326 RCU_INIT_POINTER(timeout_ext->timeout, NULL); 327 } 328 } 329 rcu_read_unlock(); 330 #endif 331 } 332 333 static void xt_ct_tg_destroy(const struct xt_tgdtor_param *par, 334 struct xt_ct_target_info_v1 *info) 335 { 336 struct nf_conn *ct = info->ct; 337 struct nf_conn_help *help; 338 339 if (ct && !nf_ct_is_untracked(ct)) { 340 help = nfct_help(ct); 341 if (help) 342 module_put(help->helper->me); 343 344 nf_ct_netns_put(par->net, par->family); 345 346 xt_ct_destroy_timeout(ct); 347 nf_ct_put(info->ct); 348 } 349 } 350 351 static void xt_ct_tg_destroy_v0(const struct xt_tgdtor_param *par) 352 { 353 struct xt_ct_target_info *info = par->targinfo; 354 struct xt_ct_target_info_v1 info_v1 = { 355 .flags = info->flags, 356 .zone = info->zone, 357 .ct_events = info->ct_events, 358 .exp_events = info->exp_events, 359 .ct = info->ct, 360 }; 361 memcpy(info_v1.helper, info->helper, sizeof(info->helper)); 362 363 xt_ct_tg_destroy(par, &info_v1); 364 } 365 366 static void xt_ct_tg_destroy_v1(const struct xt_tgdtor_param *par) 367 { 368 xt_ct_tg_destroy(par, par->targinfo); 369 } 370 371 static struct xt_target xt_ct_tg_reg[] __read_mostly = { 372 { 373 .name = "CT", 374 .family = NFPROTO_UNSPEC, 375 .targetsize = sizeof(struct xt_ct_target_info), 376 .checkentry = xt_ct_tg_check_v0, 377 .destroy = xt_ct_tg_destroy_v0, 378 .target = xt_ct_target_v0, 379 .table = "raw", 380 .me = THIS_MODULE, 381 }, 382 { 383 .name = "CT", 384 .family = NFPROTO_UNSPEC, 385 .revision = 1, 386 .targetsize = sizeof(struct xt_ct_target_info_v1), 387 .checkentry = xt_ct_tg_check_v1, 388 .destroy = xt_ct_tg_destroy_v1, 389 .target = xt_ct_target_v1, 390 .table = "raw", 391 .me = THIS_MODULE, 392 }, 393 { 394 .name = "CT", 395 .family = NFPROTO_UNSPEC, 396 .revision = 2, 397 .targetsize = sizeof(struct xt_ct_target_info_v1), 398 .checkentry = xt_ct_tg_check_v2, 399 .destroy = xt_ct_tg_destroy_v1, 400 .target = xt_ct_target_v1, 401 .table = "raw", 402 .me = THIS_MODULE, 403 }, 404 }; 405 406 static unsigned int 407 notrack_tg(struct sk_buff *skb, const struct xt_action_param *par) 408 { 409 /* Previously seen (loopback)? Ignore. */ 410 if (skb->nfct != NULL) 411 return XT_CONTINUE; 412 413 skb->nfct = &nf_ct_untracked_get()->ct_general; 414 skb->nfctinfo = IP_CT_NEW; 415 nf_conntrack_get(skb->nfct); 416 417 return XT_CONTINUE; 418 } 419 420 static int notrack_chk(const struct xt_tgchk_param *par) 421 { 422 if (!par->net->xt.notrack_deprecated_warning) { 423 pr_info("netfilter: NOTRACK target is deprecated, " 424 "use CT instead or upgrade iptables\n"); 425 par->net->xt.notrack_deprecated_warning = true; 426 } 427 return 0; 428 } 429 430 static struct xt_target notrack_tg_reg __read_mostly = { 431 .name = "NOTRACK", 432 .revision = 0, 433 .family = NFPROTO_UNSPEC, 434 .checkentry = notrack_chk, 435 .target = notrack_tg, 436 .table = "raw", 437 .me = THIS_MODULE, 438 }; 439 440 static int __init xt_ct_tg_init(void) 441 { 442 int ret; 443 444 ret = xt_register_target(¬rack_tg_reg); 445 if (ret < 0) 446 return ret; 447 448 ret = xt_register_targets(xt_ct_tg_reg, ARRAY_SIZE(xt_ct_tg_reg)); 449 if (ret < 0) { 450 xt_unregister_target(¬rack_tg_reg); 451 return ret; 452 } 453 return 0; 454 } 455 456 static void __exit xt_ct_tg_exit(void) 457 { 458 xt_unregister_targets(xt_ct_tg_reg, ARRAY_SIZE(xt_ct_tg_reg)); 459 xt_unregister_target(¬rack_tg_reg); 460 } 461 462 module_init(xt_ct_tg_init); 463 module_exit(xt_ct_tg_exit); 464 465 MODULE_LICENSE("GPL"); 466 MODULE_DESCRIPTION("Xtables: connection tracking target"); 467 MODULE_ALIAS("ipt_CT"); 468 MODULE_ALIAS("ip6t_CT"); 469 MODULE_ALIAS("ipt_NOTRACK"); 470 MODULE_ALIAS("ip6t_NOTRACK"); 471