1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * net/sched/act_ipt.c iptables target interface 4 * 5 *TODO: Add other tables. For now we only support the ipv4 table targets 6 * 7 * Copyright: Jamal Hadi Salim (2002-13) 8 */ 9 10 #include <linux/types.h> 11 #include <linux/kernel.h> 12 #include <linux/string.h> 13 #include <linux/errno.h> 14 #include <linux/skbuff.h> 15 #include <linux/rtnetlink.h> 16 #include <linux/module.h> 17 #include <linux/init.h> 18 #include <linux/slab.h> 19 #include <net/netlink.h> 20 #include <net/pkt_sched.h> 21 #include <linux/tc_act/tc_ipt.h> 22 #include <net/tc_act/tc_ipt.h> 23 24 #include <linux/netfilter_ipv4/ip_tables.h> 25 26 27 static unsigned int ipt_net_id; 28 static struct tc_action_ops act_ipt_ops; 29 30 static unsigned int xt_net_id; 31 static struct tc_action_ops act_xt_ops; 32 33 static int ipt_init_target(struct net *net, struct xt_entry_target *t, 34 char *table, unsigned int hook) 35 { 36 struct xt_tgchk_param par; 37 struct xt_target *target; 38 struct ipt_entry e = {}; 39 int ret = 0; 40 41 target = xt_request_find_target(AF_INET, t->u.user.name, 42 t->u.user.revision); 43 if (IS_ERR(target)) 44 return PTR_ERR(target); 45 46 t->u.kernel.target = target; 47 memset(&par, 0, sizeof(par)); 48 par.net = net; 49 par.table = table; 50 par.entryinfo = &e; 51 par.target = target; 52 par.targinfo = t->data; 53 par.hook_mask = hook; 54 par.family = NFPROTO_IPV4; 55 56 ret = xt_check_target(&par, t->u.target_size - sizeof(*t), 0, false); 57 if (ret < 0) { 58 module_put(t->u.kernel.target->me); 59 return ret; 60 } 61 return 0; 62 } 63 64 static void ipt_destroy_target(struct xt_entry_target *t, struct net *net) 65 { 66 struct xt_tgdtor_param par = { 67 .target = t->u.kernel.target, 68 .targinfo = t->data, 69 .family = NFPROTO_IPV4, 70 .net = net, 71 }; 72 if (par.target->destroy != NULL) 73 par.target->destroy(&par); 74 module_put(par.target->me); 75 } 76 77 static void tcf_ipt_release(struct tc_action *a) 78 { 79 struct tcf_ipt *ipt = to_ipt(a); 80 81 if (ipt->tcfi_t) { 82 ipt_destroy_target(ipt->tcfi_t, a->idrinfo->net); 83 kfree(ipt->tcfi_t); 84 } 85 kfree(ipt->tcfi_tname); 86 } 87 88 static const struct nla_policy ipt_policy[TCA_IPT_MAX + 1] = { 89 [TCA_IPT_TABLE] = { .type = NLA_STRING, .len = IFNAMSIZ }, 90 [TCA_IPT_HOOK] = { .type = NLA_U32 }, 91 [TCA_IPT_INDEX] = { .type = NLA_U32 }, 92 [TCA_IPT_TARG] = { .len = sizeof(struct xt_entry_target) }, 93 }; 94 95 static int __tcf_ipt_init(struct net *net, unsigned int id, struct nlattr *nla, 96 struct nlattr *est, struct tc_action **a, 97 const struct tc_action_ops *ops, 98 struct tcf_proto *tp, u32 flags) 99 { 100 struct tc_action_net *tn = net_generic(net, id); 101 bool bind = flags & TCA_ACT_FLAGS_BIND; 102 struct nlattr *tb[TCA_IPT_MAX + 1]; 103 struct tcf_ipt *ipt; 104 struct xt_entry_target *td, *t; 105 char *tname; 106 bool exists = false; 107 int ret = 0, err; 108 u32 hook = 0; 109 u32 index = 0; 110 111 if (nla == NULL) 112 return -EINVAL; 113 114 err = nla_parse_nested_deprecated(tb, TCA_IPT_MAX, nla, ipt_policy, 115 NULL); 116 if (err < 0) 117 return err; 118 119 if (tb[TCA_IPT_INDEX] != NULL) 120 index = nla_get_u32(tb[TCA_IPT_INDEX]); 121 122 err = tcf_idr_check_alloc(tn, &index, a, bind); 123 if (err < 0) 124 return err; 125 exists = err; 126 if (exists && bind) 127 return 0; 128 129 if (tb[TCA_IPT_HOOK] == NULL || tb[TCA_IPT_TARG] == NULL) { 130 if (exists) 131 tcf_idr_release(*a, bind); 132 else 133 tcf_idr_cleanup(tn, index); 134 return -EINVAL; 135 } 136 137 td = (struct xt_entry_target *)nla_data(tb[TCA_IPT_TARG]); 138 if (nla_len(tb[TCA_IPT_TARG]) != td->u.target_size) { 139 if (exists) 140 tcf_idr_release(*a, bind); 141 else 142 tcf_idr_cleanup(tn, index); 143 return -EINVAL; 144 } 145 146 if (!exists) { 147 ret = tcf_idr_create(tn, index, est, a, ops, bind, 148 false, 0); 149 if (ret) { 150 tcf_idr_cleanup(tn, index); 151 return ret; 152 } 153 ret = ACT_P_CREATED; 154 } else { 155 if (bind)/* dont override defaults */ 156 return 0; 157 158 if (!(flags & TCA_ACT_FLAGS_REPLACE)) { 159 tcf_idr_release(*a, bind); 160 return -EEXIST; 161 } 162 } 163 hook = nla_get_u32(tb[TCA_IPT_HOOK]); 164 165 err = -ENOMEM; 166 tname = kmalloc(IFNAMSIZ, GFP_KERNEL); 167 if (unlikely(!tname)) 168 goto err1; 169 if (tb[TCA_IPT_TABLE] == NULL || 170 nla_strscpy(tname, tb[TCA_IPT_TABLE], IFNAMSIZ) >= IFNAMSIZ) 171 strcpy(tname, "mangle"); 172 173 t = kmemdup(td, td->u.target_size, GFP_KERNEL); 174 if (unlikely(!t)) 175 goto err2; 176 177 err = ipt_init_target(net, t, tname, hook); 178 if (err < 0) 179 goto err3; 180 181 ipt = to_ipt(*a); 182 183 spin_lock_bh(&ipt->tcf_lock); 184 if (ret != ACT_P_CREATED) { 185 ipt_destroy_target(ipt->tcfi_t, net); 186 kfree(ipt->tcfi_tname); 187 kfree(ipt->tcfi_t); 188 } 189 ipt->tcfi_tname = tname; 190 ipt->tcfi_t = t; 191 ipt->tcfi_hook = hook; 192 spin_unlock_bh(&ipt->tcf_lock); 193 return ret; 194 195 err3: 196 kfree(t); 197 err2: 198 kfree(tname); 199 err1: 200 tcf_idr_release(*a, bind); 201 return err; 202 } 203 204 static int tcf_ipt_init(struct net *net, struct nlattr *nla, 205 struct nlattr *est, struct tc_action **a, 206 struct tcf_proto *tp, 207 u32 flags, struct netlink_ext_ack *extack) 208 { 209 return __tcf_ipt_init(net, ipt_net_id, nla, est, a, &act_ipt_ops, 210 tp, flags); 211 } 212 213 static int tcf_xt_init(struct net *net, struct nlattr *nla, 214 struct nlattr *est, struct tc_action **a, 215 struct tcf_proto *tp, 216 u32 flags, struct netlink_ext_ack *extack) 217 { 218 return __tcf_ipt_init(net, xt_net_id, nla, est, a, &act_xt_ops, 219 tp, flags); 220 } 221 222 static int tcf_ipt_act(struct sk_buff *skb, const struct tc_action *a, 223 struct tcf_result *res) 224 { 225 int ret = 0, result = 0; 226 struct tcf_ipt *ipt = to_ipt(a); 227 struct xt_action_param par; 228 struct nf_hook_state state = { 229 .net = dev_net(skb->dev), 230 .in = skb->dev, 231 .hook = ipt->tcfi_hook, 232 .pf = NFPROTO_IPV4, 233 }; 234 235 if (skb_unclone(skb, GFP_ATOMIC)) 236 return TC_ACT_UNSPEC; 237 238 spin_lock(&ipt->tcf_lock); 239 240 tcf_lastuse_update(&ipt->tcf_tm); 241 bstats_update(&ipt->tcf_bstats, skb); 242 243 /* yes, we have to worry about both in and out dev 244 * worry later - danger - this API seems to have changed 245 * from earlier kernels 246 */ 247 par.state = &state; 248 par.target = ipt->tcfi_t->u.kernel.target; 249 par.targinfo = ipt->tcfi_t->data; 250 ret = par.target->target(skb, &par); 251 252 switch (ret) { 253 case NF_ACCEPT: 254 result = TC_ACT_OK; 255 break; 256 case NF_DROP: 257 result = TC_ACT_SHOT; 258 ipt->tcf_qstats.drops++; 259 break; 260 case XT_CONTINUE: 261 result = TC_ACT_PIPE; 262 break; 263 default: 264 net_notice_ratelimited("tc filter: Bogus netfilter code %d assume ACCEPT\n", 265 ret); 266 result = TC_ACT_OK; 267 break; 268 } 269 spin_unlock(&ipt->tcf_lock); 270 return result; 271 272 } 273 274 static int tcf_ipt_dump(struct sk_buff *skb, struct tc_action *a, int bind, 275 int ref) 276 { 277 unsigned char *b = skb_tail_pointer(skb); 278 struct tcf_ipt *ipt = to_ipt(a); 279 struct xt_entry_target *t; 280 struct tcf_t tm; 281 struct tc_cnt c; 282 283 /* for simple targets kernel size == user size 284 * user name = target name 285 * for foolproof you need to not assume this 286 */ 287 288 spin_lock_bh(&ipt->tcf_lock); 289 t = kmemdup(ipt->tcfi_t, ipt->tcfi_t->u.user.target_size, GFP_ATOMIC); 290 if (unlikely(!t)) 291 goto nla_put_failure; 292 293 c.bindcnt = atomic_read(&ipt->tcf_bindcnt) - bind; 294 c.refcnt = refcount_read(&ipt->tcf_refcnt) - ref; 295 strcpy(t->u.user.name, ipt->tcfi_t->u.kernel.target->name); 296 297 if (nla_put(skb, TCA_IPT_TARG, ipt->tcfi_t->u.user.target_size, t) || 298 nla_put_u32(skb, TCA_IPT_INDEX, ipt->tcf_index) || 299 nla_put_u32(skb, TCA_IPT_HOOK, ipt->tcfi_hook) || 300 nla_put(skb, TCA_IPT_CNT, sizeof(struct tc_cnt), &c) || 301 nla_put_string(skb, TCA_IPT_TABLE, ipt->tcfi_tname)) 302 goto nla_put_failure; 303 304 tcf_tm_dump(&tm, &ipt->tcf_tm); 305 if (nla_put_64bit(skb, TCA_IPT_TM, sizeof(tm), &tm, TCA_IPT_PAD)) 306 goto nla_put_failure; 307 308 spin_unlock_bh(&ipt->tcf_lock); 309 kfree(t); 310 return skb->len; 311 312 nla_put_failure: 313 spin_unlock_bh(&ipt->tcf_lock); 314 nlmsg_trim(skb, b); 315 kfree(t); 316 return -1; 317 } 318 319 static int tcf_ipt_walker(struct net *net, struct sk_buff *skb, 320 struct netlink_callback *cb, int type, 321 const struct tc_action_ops *ops, 322 struct netlink_ext_ack *extack) 323 { 324 struct tc_action_net *tn = net_generic(net, ipt_net_id); 325 326 return tcf_generic_walker(tn, skb, cb, type, ops, extack); 327 } 328 329 static int tcf_ipt_search(struct net *net, struct tc_action **a, u32 index) 330 { 331 struct tc_action_net *tn = net_generic(net, ipt_net_id); 332 333 return tcf_idr_search(tn, a, index); 334 } 335 336 static struct tc_action_ops act_ipt_ops = { 337 .kind = "ipt", 338 .id = TCA_ID_IPT, 339 .owner = THIS_MODULE, 340 .act = tcf_ipt_act, 341 .dump = tcf_ipt_dump, 342 .cleanup = tcf_ipt_release, 343 .init = tcf_ipt_init, 344 .walk = tcf_ipt_walker, 345 .lookup = tcf_ipt_search, 346 .size = sizeof(struct tcf_ipt), 347 }; 348 349 static __net_init int ipt_init_net(struct net *net) 350 { 351 struct tc_action_net *tn = net_generic(net, ipt_net_id); 352 353 return tc_action_net_init(net, tn, &act_ipt_ops); 354 } 355 356 static void __net_exit ipt_exit_net(struct list_head *net_list) 357 { 358 tc_action_net_exit(net_list, ipt_net_id); 359 } 360 361 static struct pernet_operations ipt_net_ops = { 362 .init = ipt_init_net, 363 .exit_batch = ipt_exit_net, 364 .id = &ipt_net_id, 365 .size = sizeof(struct tc_action_net), 366 }; 367 368 static int tcf_xt_walker(struct net *net, struct sk_buff *skb, 369 struct netlink_callback *cb, int type, 370 const struct tc_action_ops *ops, 371 struct netlink_ext_ack *extack) 372 { 373 struct tc_action_net *tn = net_generic(net, xt_net_id); 374 375 return tcf_generic_walker(tn, skb, cb, type, ops, extack); 376 } 377 378 static int tcf_xt_search(struct net *net, struct tc_action **a, u32 index) 379 { 380 struct tc_action_net *tn = net_generic(net, xt_net_id); 381 382 return tcf_idr_search(tn, a, index); 383 } 384 385 static struct tc_action_ops act_xt_ops = { 386 .kind = "xt", 387 .id = TCA_ID_XT, 388 .owner = THIS_MODULE, 389 .act = tcf_ipt_act, 390 .dump = tcf_ipt_dump, 391 .cleanup = tcf_ipt_release, 392 .init = tcf_xt_init, 393 .walk = tcf_xt_walker, 394 .lookup = tcf_xt_search, 395 .size = sizeof(struct tcf_ipt), 396 }; 397 398 static __net_init int xt_init_net(struct net *net) 399 { 400 struct tc_action_net *tn = net_generic(net, xt_net_id); 401 402 return tc_action_net_init(net, tn, &act_xt_ops); 403 } 404 405 static void __net_exit xt_exit_net(struct list_head *net_list) 406 { 407 tc_action_net_exit(net_list, xt_net_id); 408 } 409 410 static struct pernet_operations xt_net_ops = { 411 .init = xt_init_net, 412 .exit_batch = xt_exit_net, 413 .id = &xt_net_id, 414 .size = sizeof(struct tc_action_net), 415 }; 416 417 MODULE_AUTHOR("Jamal Hadi Salim(2002-13)"); 418 MODULE_DESCRIPTION("Iptables target actions"); 419 MODULE_LICENSE("GPL"); 420 MODULE_ALIAS("act_xt"); 421 422 static int __init ipt_init_module(void) 423 { 424 int ret1, ret2; 425 426 ret1 = tcf_register_action(&act_xt_ops, &xt_net_ops); 427 if (ret1 < 0) 428 pr_err("Failed to load xt action\n"); 429 430 ret2 = tcf_register_action(&act_ipt_ops, &ipt_net_ops); 431 if (ret2 < 0) 432 pr_err("Failed to load ipt action\n"); 433 434 if (ret1 < 0 && ret2 < 0) { 435 return ret1; 436 } else 437 return 0; 438 } 439 440 static void __exit ipt_cleanup_module(void) 441 { 442 tcf_unregister_action(&act_ipt_ops, &ipt_net_ops); 443 tcf_unregister_action(&act_xt_ops, &xt_net_ops); 444 } 445 446 module_init(ipt_init_module); 447 module_exit(ipt_cleanup_module); 448