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, int ovr, int bind, 98 struct tcf_proto *tp, u32 flags) 99 { 100 struct tc_action_net *tn = net_generic(net, id); 101 struct nlattr *tb[TCA_IPT_MAX + 1]; 102 struct tcf_ipt *ipt; 103 struct xt_entry_target *td, *t; 104 char *tname; 105 bool exists = false; 106 int ret = 0, err; 107 u32 hook = 0; 108 u32 index = 0; 109 110 if (nla == NULL) 111 return -EINVAL; 112 113 err = nla_parse_nested_deprecated(tb, TCA_IPT_MAX, nla, ipt_policy, 114 NULL); 115 if (err < 0) 116 return err; 117 118 if (tb[TCA_IPT_INDEX] != NULL) 119 index = nla_get_u32(tb[TCA_IPT_INDEX]); 120 121 err = tcf_idr_check_alloc(tn, &index, a, bind); 122 if (err < 0) 123 return err; 124 exists = err; 125 if (exists && bind) 126 return 0; 127 128 if (tb[TCA_IPT_HOOK] == NULL || tb[TCA_IPT_TARG] == NULL) { 129 if (exists) 130 tcf_idr_release(*a, bind); 131 else 132 tcf_idr_cleanup(tn, index); 133 return -EINVAL; 134 } 135 136 td = (struct xt_entry_target *)nla_data(tb[TCA_IPT_TARG]); 137 if (nla_len(tb[TCA_IPT_TARG]) != td->u.target_size) { 138 if (exists) 139 tcf_idr_release(*a, bind); 140 else 141 tcf_idr_cleanup(tn, index); 142 return -EINVAL; 143 } 144 145 if (!exists) { 146 ret = tcf_idr_create(tn, index, est, a, ops, bind, 147 false, 0); 148 if (ret) { 149 tcf_idr_cleanup(tn, index); 150 return ret; 151 } 152 ret = ACT_P_CREATED; 153 } else { 154 if (bind)/* dont override defaults */ 155 return 0; 156 157 if (!ovr) { 158 tcf_idr_release(*a, bind); 159 return -EEXIST; 160 } 161 } 162 hook = nla_get_u32(tb[TCA_IPT_HOOK]); 163 164 err = -ENOMEM; 165 tname = kmalloc(IFNAMSIZ, GFP_KERNEL); 166 if (unlikely(!tname)) 167 goto err1; 168 if (tb[TCA_IPT_TABLE] == NULL || 169 nla_strlcpy(tname, tb[TCA_IPT_TABLE], IFNAMSIZ) >= IFNAMSIZ) 170 strcpy(tname, "mangle"); 171 172 t = kmemdup(td, td->u.target_size, GFP_KERNEL); 173 if (unlikely(!t)) 174 goto err2; 175 176 err = ipt_init_target(net, t, tname, hook); 177 if (err < 0) 178 goto err3; 179 180 ipt = to_ipt(*a); 181 182 spin_lock_bh(&ipt->tcf_lock); 183 if (ret != ACT_P_CREATED) { 184 ipt_destroy_target(ipt->tcfi_t, net); 185 kfree(ipt->tcfi_tname); 186 kfree(ipt->tcfi_t); 187 } 188 ipt->tcfi_tname = tname; 189 ipt->tcfi_t = t; 190 ipt->tcfi_hook = hook; 191 spin_unlock_bh(&ipt->tcf_lock); 192 if (ret == ACT_P_CREATED) 193 tcf_idr_insert(tn, *a); 194 return ret; 195 196 err3: 197 kfree(t); 198 err2: 199 kfree(tname); 200 err1: 201 tcf_idr_release(*a, bind); 202 return err; 203 } 204 205 static int tcf_ipt_init(struct net *net, struct nlattr *nla, 206 struct nlattr *est, struct tc_action **a, int ovr, 207 int bind, bool rtnl_held, struct tcf_proto *tp, 208 u32 flags, struct netlink_ext_ack *extack) 209 { 210 return __tcf_ipt_init(net, ipt_net_id, nla, est, a, &act_ipt_ops, ovr, 211 bind, tp, flags); 212 } 213 214 static int tcf_xt_init(struct net *net, struct nlattr *nla, 215 struct nlattr *est, struct tc_action **a, int ovr, 216 int bind, bool unlocked, struct tcf_proto *tp, 217 u32 flags, struct netlink_ext_ack *extack) 218 { 219 return __tcf_ipt_init(net, xt_net_id, nla, est, a, &act_xt_ops, ovr, 220 bind, tp, flags); 221 } 222 223 static int tcf_ipt_act(struct sk_buff *skb, const struct tc_action *a, 224 struct tcf_result *res) 225 { 226 int ret = 0, result = 0; 227 struct tcf_ipt *ipt = to_ipt(a); 228 struct xt_action_param par; 229 struct nf_hook_state state = { 230 .net = dev_net(skb->dev), 231 .in = skb->dev, 232 .hook = ipt->tcfi_hook, 233 .pf = NFPROTO_IPV4, 234 }; 235 236 if (skb_unclone(skb, GFP_ATOMIC)) 237 return TC_ACT_UNSPEC; 238 239 spin_lock(&ipt->tcf_lock); 240 241 tcf_lastuse_update(&ipt->tcf_tm); 242 bstats_update(&ipt->tcf_bstats, skb); 243 244 /* yes, we have to worry about both in and out dev 245 * worry later - danger - this API seems to have changed 246 * from earlier kernels 247 */ 248 par.state = &state; 249 par.target = ipt->tcfi_t->u.kernel.target; 250 par.targinfo = ipt->tcfi_t->data; 251 ret = par.target->target(skb, &par); 252 253 switch (ret) { 254 case NF_ACCEPT: 255 result = TC_ACT_OK; 256 break; 257 case NF_DROP: 258 result = TC_ACT_SHOT; 259 ipt->tcf_qstats.drops++; 260 break; 261 case XT_CONTINUE: 262 result = TC_ACT_PIPE; 263 break; 264 default: 265 net_notice_ratelimited("tc filter: Bogus netfilter code %d assume ACCEPT\n", 266 ret); 267 result = TC_ACT_OK; 268 break; 269 } 270 spin_unlock(&ipt->tcf_lock); 271 return result; 272 273 } 274 275 static int tcf_ipt_dump(struct sk_buff *skb, struct tc_action *a, int bind, 276 int ref) 277 { 278 unsigned char *b = skb_tail_pointer(skb); 279 struct tcf_ipt *ipt = to_ipt(a); 280 struct xt_entry_target *t; 281 struct tcf_t tm; 282 struct tc_cnt c; 283 284 /* for simple targets kernel size == user size 285 * user name = target name 286 * for foolproof you need to not assume this 287 */ 288 289 spin_lock_bh(&ipt->tcf_lock); 290 t = kmemdup(ipt->tcfi_t, ipt->tcfi_t->u.user.target_size, GFP_ATOMIC); 291 if (unlikely(!t)) 292 goto nla_put_failure; 293 294 c.bindcnt = atomic_read(&ipt->tcf_bindcnt) - bind; 295 c.refcnt = refcount_read(&ipt->tcf_refcnt) - ref; 296 strcpy(t->u.user.name, ipt->tcfi_t->u.kernel.target->name); 297 298 if (nla_put(skb, TCA_IPT_TARG, ipt->tcfi_t->u.user.target_size, t) || 299 nla_put_u32(skb, TCA_IPT_INDEX, ipt->tcf_index) || 300 nla_put_u32(skb, TCA_IPT_HOOK, ipt->tcfi_hook) || 301 nla_put(skb, TCA_IPT_CNT, sizeof(struct tc_cnt), &c) || 302 nla_put_string(skb, TCA_IPT_TABLE, ipt->tcfi_tname)) 303 goto nla_put_failure; 304 305 tcf_tm_dump(&tm, &ipt->tcf_tm); 306 if (nla_put_64bit(skb, TCA_IPT_TM, sizeof(tm), &tm, TCA_IPT_PAD)) 307 goto nla_put_failure; 308 309 spin_unlock_bh(&ipt->tcf_lock); 310 kfree(t); 311 return skb->len; 312 313 nla_put_failure: 314 spin_unlock_bh(&ipt->tcf_lock); 315 nlmsg_trim(skb, b); 316 kfree(t); 317 return -1; 318 } 319 320 static int tcf_ipt_walker(struct net *net, struct sk_buff *skb, 321 struct netlink_callback *cb, int type, 322 const struct tc_action_ops *ops, 323 struct netlink_ext_ack *extack) 324 { 325 struct tc_action_net *tn = net_generic(net, ipt_net_id); 326 327 return tcf_generic_walker(tn, skb, cb, type, ops, extack); 328 } 329 330 static int tcf_ipt_search(struct net *net, struct tc_action **a, u32 index) 331 { 332 struct tc_action_net *tn = net_generic(net, ipt_net_id); 333 334 return tcf_idr_search(tn, a, index); 335 } 336 337 static struct tc_action_ops act_ipt_ops = { 338 .kind = "ipt", 339 .id = TCA_ID_IPT, 340 .owner = THIS_MODULE, 341 .act = tcf_ipt_act, 342 .dump = tcf_ipt_dump, 343 .cleanup = tcf_ipt_release, 344 .init = tcf_ipt_init, 345 .walk = tcf_ipt_walker, 346 .lookup = tcf_ipt_search, 347 .size = sizeof(struct tcf_ipt), 348 }; 349 350 static __net_init int ipt_init_net(struct net *net) 351 { 352 struct tc_action_net *tn = net_generic(net, ipt_net_id); 353 354 return tc_action_net_init(net, tn, &act_ipt_ops); 355 } 356 357 static void __net_exit ipt_exit_net(struct list_head *net_list) 358 { 359 tc_action_net_exit(net_list, ipt_net_id); 360 } 361 362 static struct pernet_operations ipt_net_ops = { 363 .init = ipt_init_net, 364 .exit_batch = ipt_exit_net, 365 .id = &ipt_net_id, 366 .size = sizeof(struct tc_action_net), 367 }; 368 369 static int tcf_xt_walker(struct net *net, struct sk_buff *skb, 370 struct netlink_callback *cb, int type, 371 const struct tc_action_ops *ops, 372 struct netlink_ext_ack *extack) 373 { 374 struct tc_action_net *tn = net_generic(net, xt_net_id); 375 376 return tcf_generic_walker(tn, skb, cb, type, ops, extack); 377 } 378 379 static int tcf_xt_search(struct net *net, struct tc_action **a, u32 index) 380 { 381 struct tc_action_net *tn = net_generic(net, xt_net_id); 382 383 return tcf_idr_search(tn, a, index); 384 } 385 386 static struct tc_action_ops act_xt_ops = { 387 .kind = "xt", 388 .id = TCA_ID_XT, 389 .owner = THIS_MODULE, 390 .act = tcf_ipt_act, 391 .dump = tcf_ipt_dump, 392 .cleanup = tcf_ipt_release, 393 .init = tcf_xt_init, 394 .walk = tcf_xt_walker, 395 .lookup = tcf_xt_search, 396 .size = sizeof(struct tcf_ipt), 397 }; 398 399 static __net_init int xt_init_net(struct net *net) 400 { 401 struct tc_action_net *tn = net_generic(net, xt_net_id); 402 403 return tc_action_net_init(net, tn, &act_xt_ops); 404 } 405 406 static void __net_exit xt_exit_net(struct list_head *net_list) 407 { 408 tc_action_net_exit(net_list, xt_net_id); 409 } 410 411 static struct pernet_operations xt_net_ops = { 412 .init = xt_init_net, 413 .exit_batch = xt_exit_net, 414 .id = &xt_net_id, 415 .size = sizeof(struct tc_action_net), 416 }; 417 418 MODULE_AUTHOR("Jamal Hadi Salim(2002-13)"); 419 MODULE_DESCRIPTION("Iptables target actions"); 420 MODULE_LICENSE("GPL"); 421 MODULE_ALIAS("act_xt"); 422 423 static int __init ipt_init_module(void) 424 { 425 int ret1, ret2; 426 427 ret1 = tcf_register_action(&act_xt_ops, &xt_net_ops); 428 if (ret1 < 0) 429 pr_err("Failed to load xt action\n"); 430 431 ret2 = tcf_register_action(&act_ipt_ops, &ipt_net_ops); 432 if (ret2 < 0) 433 pr_err("Failed to load ipt action\n"); 434 435 if (ret1 < 0 && ret2 < 0) { 436 return ret1; 437 } else 438 return 0; 439 } 440 441 static void __exit ipt_cleanup_module(void) 442 { 443 tcf_unregister_action(&act_ipt_ops, &ipt_net_ops); 444 tcf_unregister_action(&act_xt_ops, &xt_net_ops); 445 } 446 447 module_init(ipt_init_module); 448 module_exit(ipt_cleanup_module); 449