1 /* 2 * Copyright (c) 2010 Patrick McHardy <[email protected]> 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 static int 107 xt_ct_set_timeout(struct nf_conn *ct, const struct xt_tgchk_param *par, 108 const char *timeout_name) 109 { 110 #ifdef CONFIG_NF_CONNTRACK_TIMEOUT 111 const struct nf_conntrack_l4proto *l4proto; 112 u8 proto; 113 114 proto = xt_ct_find_proto(par); 115 if (!proto) { 116 pr_info_ratelimited("You must specify a L4 protocol and not " 117 "use inversions on it"); 118 return -EINVAL; 119 } 120 l4proto = nf_ct_l4proto_find(proto); 121 return nf_ct_set_timeout(par->net, ct, par->family, l4proto->l4proto, 122 timeout_name); 123 124 #else 125 return -EOPNOTSUPP; 126 #endif 127 } 128 129 static u16 xt_ct_flags_to_dir(const struct xt_ct_target_info_v1 *info) 130 { 131 switch (info->flags & (XT_CT_ZONE_DIR_ORIG | 132 XT_CT_ZONE_DIR_REPL)) { 133 case XT_CT_ZONE_DIR_ORIG: 134 return NF_CT_ZONE_DIR_ORIG; 135 case XT_CT_ZONE_DIR_REPL: 136 return NF_CT_ZONE_DIR_REPL; 137 default: 138 return NF_CT_DEFAULT_ZONE_DIR; 139 } 140 } 141 142 static int xt_ct_tg_check(const struct xt_tgchk_param *par, 143 struct xt_ct_target_info_v1 *info) 144 { 145 struct nf_conntrack_zone zone; 146 struct nf_conn_help *help; 147 struct nf_conn *ct; 148 int ret = -EOPNOTSUPP; 149 150 if (info->flags & XT_CT_NOTRACK) { 151 ct = NULL; 152 goto out; 153 } 154 155 #ifndef CONFIG_NF_CONNTRACK_ZONES 156 if (info->zone || info->flags & (XT_CT_ZONE_DIR_ORIG | 157 XT_CT_ZONE_DIR_REPL | 158 XT_CT_ZONE_MARK)) 159 goto err1; 160 #endif 161 162 ret = nf_ct_netns_get(par->net, par->family); 163 if (ret < 0) 164 goto err1; 165 166 memset(&zone, 0, sizeof(zone)); 167 zone.id = info->zone; 168 zone.dir = xt_ct_flags_to_dir(info); 169 if (info->flags & XT_CT_ZONE_MARK) 170 zone.flags |= NF_CT_FLAG_MARK; 171 172 ct = nf_ct_tmpl_alloc(par->net, &zone, GFP_KERNEL); 173 if (!ct) { 174 ret = -ENOMEM; 175 goto err2; 176 } 177 178 ret = 0; 179 if ((info->ct_events || info->exp_events) && 180 !nf_ct_ecache_ext_add(ct, info->ct_events, info->exp_events, 181 GFP_KERNEL)) { 182 ret = -EINVAL; 183 goto err3; 184 } 185 186 if (info->helper[0]) { 187 if (strnlen(info->helper, sizeof(info->helper)) == sizeof(info->helper)) { 188 ret = -ENAMETOOLONG; 189 goto err3; 190 } 191 192 ret = xt_ct_set_helper(ct, info->helper, par); 193 if (ret < 0) 194 goto err3; 195 } 196 197 if (info->timeout[0]) { 198 if (strnlen(info->timeout, sizeof(info->timeout)) == sizeof(info->timeout)) { 199 ret = -ENAMETOOLONG; 200 goto err4; 201 } 202 203 ret = xt_ct_set_timeout(ct, par, info->timeout); 204 if (ret < 0) 205 goto err4; 206 } 207 __set_bit(IPS_CONFIRMED_BIT, &ct->status); 208 nf_conntrack_get(&ct->ct_general); 209 out: 210 info->ct = ct; 211 return 0; 212 213 err4: 214 help = nfct_help(ct); 215 if (help) 216 nf_conntrack_helper_put(help->helper); 217 err3: 218 nf_ct_tmpl_free(ct); 219 err2: 220 nf_ct_netns_put(par->net, par->family); 221 err1: 222 return ret; 223 } 224 225 static int xt_ct_tg_check_v0(const struct xt_tgchk_param *par) 226 { 227 struct xt_ct_target_info *info = par->targinfo; 228 struct xt_ct_target_info_v1 info_v1 = { 229 .flags = info->flags, 230 .zone = info->zone, 231 .ct_events = info->ct_events, 232 .exp_events = info->exp_events, 233 }; 234 int ret; 235 236 if (info->flags & ~XT_CT_NOTRACK) 237 return -EINVAL; 238 239 memcpy(info_v1.helper, info->helper, sizeof(info->helper)); 240 241 ret = xt_ct_tg_check(par, &info_v1); 242 if (ret < 0) 243 return ret; 244 245 info->ct = info_v1.ct; 246 247 return ret; 248 } 249 250 static int xt_ct_tg_check_v1(const struct xt_tgchk_param *par) 251 { 252 struct xt_ct_target_info_v1 *info = par->targinfo; 253 254 if (info->flags & ~XT_CT_NOTRACK) 255 return -EINVAL; 256 257 return xt_ct_tg_check(par, par->targinfo); 258 } 259 260 static int xt_ct_tg_check_v2(const struct xt_tgchk_param *par) 261 { 262 struct xt_ct_target_info_v1 *info = par->targinfo; 263 264 if (info->flags & ~XT_CT_MASK) 265 return -EINVAL; 266 267 return xt_ct_tg_check(par, par->targinfo); 268 } 269 270 static void xt_ct_tg_destroy(const struct xt_tgdtor_param *par, 271 struct xt_ct_target_info_v1 *info) 272 { 273 struct nf_conn *ct = info->ct; 274 struct nf_conn_help *help; 275 276 if (ct) { 277 help = nfct_help(ct); 278 if (help) 279 nf_conntrack_helper_put(help->helper); 280 281 nf_ct_netns_put(par->net, par->family); 282 283 nf_ct_destroy_timeout(ct); 284 nf_ct_put(info->ct); 285 } 286 } 287 288 static void xt_ct_tg_destroy_v0(const struct xt_tgdtor_param *par) 289 { 290 struct xt_ct_target_info *info = par->targinfo; 291 struct xt_ct_target_info_v1 info_v1 = { 292 .flags = info->flags, 293 .zone = info->zone, 294 .ct_events = info->ct_events, 295 .exp_events = info->exp_events, 296 .ct = info->ct, 297 }; 298 memcpy(info_v1.helper, info->helper, sizeof(info->helper)); 299 300 xt_ct_tg_destroy(par, &info_v1); 301 } 302 303 static void xt_ct_tg_destroy_v1(const struct xt_tgdtor_param *par) 304 { 305 xt_ct_tg_destroy(par, par->targinfo); 306 } 307 308 static struct xt_target xt_ct_tg_reg[] __read_mostly = { 309 { 310 .name = "CT", 311 .family = NFPROTO_UNSPEC, 312 .targetsize = sizeof(struct xt_ct_target_info), 313 .usersize = offsetof(struct xt_ct_target_info, ct), 314 .checkentry = xt_ct_tg_check_v0, 315 .destroy = xt_ct_tg_destroy_v0, 316 .target = xt_ct_target_v0, 317 .table = "raw", 318 .me = THIS_MODULE, 319 }, 320 { 321 .name = "CT", 322 .family = NFPROTO_UNSPEC, 323 .revision = 1, 324 .targetsize = sizeof(struct xt_ct_target_info_v1), 325 .usersize = offsetof(struct xt_ct_target_info, ct), 326 .checkentry = xt_ct_tg_check_v1, 327 .destroy = xt_ct_tg_destroy_v1, 328 .target = xt_ct_target_v1, 329 .table = "raw", 330 .me = THIS_MODULE, 331 }, 332 { 333 .name = "CT", 334 .family = NFPROTO_UNSPEC, 335 .revision = 2, 336 .targetsize = sizeof(struct xt_ct_target_info_v1), 337 .usersize = offsetof(struct xt_ct_target_info, ct), 338 .checkentry = xt_ct_tg_check_v2, 339 .destroy = xt_ct_tg_destroy_v1, 340 .target = xt_ct_target_v1, 341 .table = "raw", 342 .me = THIS_MODULE, 343 }, 344 }; 345 346 static unsigned int 347 notrack_tg(struct sk_buff *skb, const struct xt_action_param *par) 348 { 349 /* Previously seen (loopback)? Ignore. */ 350 if (skb->_nfct != 0) 351 return XT_CONTINUE; 352 353 nf_ct_set(skb, NULL, IP_CT_UNTRACKED); 354 355 return XT_CONTINUE; 356 } 357 358 static int notrack_chk(const struct xt_tgchk_param *par) 359 { 360 if (!par->net->xt.notrack_deprecated_warning) { 361 pr_info("netfilter: NOTRACK target is deprecated, " 362 "use CT instead or upgrade iptables\n"); 363 par->net->xt.notrack_deprecated_warning = true; 364 } 365 return 0; 366 } 367 368 static struct xt_target notrack_tg_reg __read_mostly = { 369 .name = "NOTRACK", 370 .revision = 0, 371 .family = NFPROTO_UNSPEC, 372 .checkentry = notrack_chk, 373 .target = notrack_tg, 374 .table = "raw", 375 .me = THIS_MODULE, 376 }; 377 378 static int __init xt_ct_tg_init(void) 379 { 380 int ret; 381 382 ret = xt_register_target(¬rack_tg_reg); 383 if (ret < 0) 384 return ret; 385 386 ret = xt_register_targets(xt_ct_tg_reg, ARRAY_SIZE(xt_ct_tg_reg)); 387 if (ret < 0) { 388 xt_unregister_target(¬rack_tg_reg); 389 return ret; 390 } 391 return 0; 392 } 393 394 static void __exit xt_ct_tg_exit(void) 395 { 396 xt_unregister_targets(xt_ct_tg_reg, ARRAY_SIZE(xt_ct_tg_reg)); 397 xt_unregister_target(¬rack_tg_reg); 398 } 399 400 module_init(xt_ct_tg_init); 401 module_exit(xt_ct_tg_exit); 402 403 MODULE_LICENSE("GPL"); 404 MODULE_DESCRIPTION("Xtables: connection tracking target"); 405 MODULE_ALIAS("ipt_CT"); 406 MODULE_ALIAS("ip6t_CT"); 407 MODULE_ALIAS("ipt_NOTRACK"); 408 MODULE_ALIAS("ip6t_NOTRACK"); 409