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 #include <net/tc_wrapper.h> 24 #include <net/ip.h> 25 26 #include <linux/netfilter_ipv4/ip_tables.h> 27 28 29 static struct tc_action_ops act_ipt_ops; 30 static struct tc_action_ops act_xt_ops; 31 32 static int ipt_init_target(struct net *net, struct xt_entry_target *t, 33 char *table, unsigned int hook) 34 { 35 struct xt_tgchk_param par; 36 struct xt_target *target; 37 struct ipt_entry e = {}; 38 int ret = 0; 39 40 target = xt_request_find_target(AF_INET, t->u.user.name, 41 t->u.user.revision); 42 if (IS_ERR(target)) 43 return PTR_ERR(target); 44 45 t->u.kernel.target = target; 46 memset(&par, 0, sizeof(par)); 47 par.net = net; 48 par.table = table; 49 par.entryinfo = &e; 50 par.target = target; 51 par.targinfo = t->data; 52 par.hook_mask = 1 << hook; 53 par.family = NFPROTO_IPV4; 54 55 ret = xt_check_target(&par, t->u.target_size - sizeof(*t), 0, false); 56 if (ret < 0) { 57 module_put(t->u.kernel.target->me); 58 return ret; 59 } 60 return 0; 61 } 62 63 static void ipt_destroy_target(struct xt_entry_target *t, struct net *net) 64 { 65 struct xt_tgdtor_param par = { 66 .target = t->u.kernel.target, 67 .targinfo = t->data, 68 .family = NFPROTO_IPV4, 69 .net = net, 70 }; 71 if (par.target->destroy != NULL) 72 par.target->destroy(&par); 73 module_put(par.target->me); 74 } 75 76 static void tcf_ipt_release(struct tc_action *a) 77 { 78 struct tcf_ipt *ipt = to_ipt(a); 79 80 if (ipt->tcfi_t) { 81 ipt_destroy_target(ipt->tcfi_t, a->idrinfo->net); 82 kfree(ipt->tcfi_t); 83 } 84 kfree(ipt->tcfi_tname); 85 } 86 87 static const struct nla_policy ipt_policy[TCA_IPT_MAX + 1] = { 88 [TCA_IPT_TABLE] = { .type = NLA_STRING, .len = IFNAMSIZ }, 89 [TCA_IPT_HOOK] = NLA_POLICY_RANGE(NLA_U32, NF_INET_PRE_ROUTING, 90 NF_INET_NUMHOOKS), 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, flags); 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 } 163 164 err = -EINVAL; 165 hook = nla_get_u32(tb[TCA_IPT_HOOK]); 166 switch (hook) { 167 case NF_INET_PRE_ROUTING: 168 break; 169 case NF_INET_POST_ROUTING: 170 break; 171 default: 172 goto err1; 173 } 174 175 if (tb[TCA_IPT_TABLE]) { 176 /* mangle only for now */ 177 if (nla_strcmp(tb[TCA_IPT_TABLE], "mangle")) 178 goto err1; 179 } 180 181 tname = kstrdup("mangle", GFP_KERNEL); 182 if (unlikely(!tname)) 183 goto err1; 184 185 t = kmemdup(td, td->u.target_size, GFP_KERNEL); 186 if (unlikely(!t)) 187 goto err2; 188 189 err = ipt_init_target(net, t, tname, hook); 190 if (err < 0) 191 goto err3; 192 193 ipt = to_ipt(*a); 194 195 spin_lock_bh(&ipt->tcf_lock); 196 if (ret != ACT_P_CREATED) { 197 ipt_destroy_target(ipt->tcfi_t, net); 198 kfree(ipt->tcfi_tname); 199 kfree(ipt->tcfi_t); 200 } 201 ipt->tcfi_tname = tname; 202 ipt->tcfi_t = t; 203 ipt->tcfi_hook = hook; 204 spin_unlock_bh(&ipt->tcf_lock); 205 return ret; 206 207 err3: 208 kfree(t); 209 err2: 210 kfree(tname); 211 err1: 212 tcf_idr_release(*a, bind); 213 return err; 214 } 215 216 static int tcf_ipt_init(struct net *net, struct nlattr *nla, 217 struct nlattr *est, struct tc_action **a, 218 struct tcf_proto *tp, 219 u32 flags, struct netlink_ext_ack *extack) 220 { 221 return __tcf_ipt_init(net, act_ipt_ops.net_id, nla, est, 222 a, &act_ipt_ops, tp, flags); 223 } 224 225 static int tcf_xt_init(struct net *net, struct nlattr *nla, 226 struct nlattr *est, struct tc_action **a, 227 struct tcf_proto *tp, 228 u32 flags, struct netlink_ext_ack *extack) 229 { 230 return __tcf_ipt_init(net, act_xt_ops.net_id, nla, est, 231 a, &act_xt_ops, tp, flags); 232 } 233 234 static bool tcf_ipt_act_check(struct sk_buff *skb) 235 { 236 const struct iphdr *iph; 237 unsigned int nhoff, len; 238 239 if (!pskb_may_pull(skb, sizeof(struct iphdr))) 240 return false; 241 242 nhoff = skb_network_offset(skb); 243 iph = ip_hdr(skb); 244 if (iph->ihl < 5 || iph->version != 4) 245 return false; 246 247 len = skb_ip_totlen(skb); 248 if (skb->len < nhoff + len || len < (iph->ihl * 4u)) 249 return false; 250 251 return pskb_may_pull(skb, iph->ihl * 4u); 252 } 253 254 TC_INDIRECT_SCOPE int tcf_ipt_act(struct sk_buff *skb, 255 const struct tc_action *a, 256 struct tcf_result *res) 257 { 258 char saved_cb[sizeof_field(struct sk_buff, cb)]; 259 int ret = 0, result = 0; 260 struct tcf_ipt *ipt = to_ipt(a); 261 struct xt_action_param par; 262 struct nf_hook_state state = { 263 .net = dev_net(skb->dev), 264 .in = skb->dev, 265 .hook = ipt->tcfi_hook, 266 .pf = NFPROTO_IPV4, 267 }; 268 269 if (skb_protocol(skb, false) != htons(ETH_P_IP)) 270 return TC_ACT_UNSPEC; 271 272 if (skb_unclone(skb, GFP_ATOMIC)) 273 return TC_ACT_UNSPEC; 274 275 if (!tcf_ipt_act_check(skb)) 276 return TC_ACT_UNSPEC; 277 278 if (state.hook == NF_INET_POST_ROUTING) { 279 if (!skb_dst(skb)) 280 return TC_ACT_UNSPEC; 281 282 state.out = skb->dev; 283 } 284 285 memcpy(saved_cb, skb->cb, sizeof(saved_cb)); 286 287 spin_lock(&ipt->tcf_lock); 288 289 tcf_lastuse_update(&ipt->tcf_tm); 290 bstats_update(&ipt->tcf_bstats, skb); 291 292 /* yes, we have to worry about both in and out dev 293 * worry later - danger - this API seems to have changed 294 * from earlier kernels 295 */ 296 par.state = &state; 297 par.target = ipt->tcfi_t->u.kernel.target; 298 par.targinfo = ipt->tcfi_t->data; 299 300 memset(IPCB(skb), 0, sizeof(struct inet_skb_parm)); 301 302 ret = par.target->target(skb, &par); 303 304 switch (ret) { 305 case NF_ACCEPT: 306 result = TC_ACT_OK; 307 break; 308 case NF_DROP: 309 result = TC_ACT_SHOT; 310 ipt->tcf_qstats.drops++; 311 break; 312 case XT_CONTINUE: 313 result = TC_ACT_PIPE; 314 break; 315 default: 316 net_notice_ratelimited("tc filter: Bogus netfilter code %d assume ACCEPT\n", 317 ret); 318 result = TC_ACT_OK; 319 break; 320 } 321 spin_unlock(&ipt->tcf_lock); 322 323 memcpy(skb->cb, saved_cb, sizeof(skb->cb)); 324 325 return result; 326 327 } 328 329 static int tcf_ipt_dump(struct sk_buff *skb, struct tc_action *a, int bind, 330 int ref) 331 { 332 unsigned char *b = skb_tail_pointer(skb); 333 struct tcf_ipt *ipt = to_ipt(a); 334 struct xt_entry_target *t; 335 struct tcf_t tm; 336 struct tc_cnt c; 337 338 /* for simple targets kernel size == user size 339 * user name = target name 340 * for foolproof you need to not assume this 341 */ 342 343 spin_lock_bh(&ipt->tcf_lock); 344 t = kmemdup(ipt->tcfi_t, ipt->tcfi_t->u.user.target_size, GFP_ATOMIC); 345 if (unlikely(!t)) 346 goto nla_put_failure; 347 348 c.bindcnt = atomic_read(&ipt->tcf_bindcnt) - bind; 349 c.refcnt = refcount_read(&ipt->tcf_refcnt) - ref; 350 strcpy(t->u.user.name, ipt->tcfi_t->u.kernel.target->name); 351 352 if (nla_put(skb, TCA_IPT_TARG, ipt->tcfi_t->u.user.target_size, t) || 353 nla_put_u32(skb, TCA_IPT_INDEX, ipt->tcf_index) || 354 nla_put_u32(skb, TCA_IPT_HOOK, ipt->tcfi_hook) || 355 nla_put(skb, TCA_IPT_CNT, sizeof(struct tc_cnt), &c) || 356 nla_put_string(skb, TCA_IPT_TABLE, ipt->tcfi_tname)) 357 goto nla_put_failure; 358 359 tcf_tm_dump(&tm, &ipt->tcf_tm); 360 if (nla_put_64bit(skb, TCA_IPT_TM, sizeof(tm), &tm, TCA_IPT_PAD)) 361 goto nla_put_failure; 362 363 spin_unlock_bh(&ipt->tcf_lock); 364 kfree(t); 365 return skb->len; 366 367 nla_put_failure: 368 spin_unlock_bh(&ipt->tcf_lock); 369 nlmsg_trim(skb, b); 370 kfree(t); 371 return -1; 372 } 373 374 static struct tc_action_ops act_ipt_ops = { 375 .kind = "ipt", 376 .id = TCA_ID_IPT, 377 .owner = THIS_MODULE, 378 .act = tcf_ipt_act, 379 .dump = tcf_ipt_dump, 380 .cleanup = tcf_ipt_release, 381 .init = tcf_ipt_init, 382 .size = sizeof(struct tcf_ipt), 383 }; 384 385 static __net_init int ipt_init_net(struct net *net) 386 { 387 struct tc_action_net *tn = net_generic(net, act_ipt_ops.net_id); 388 389 return tc_action_net_init(net, tn, &act_ipt_ops); 390 } 391 392 static void __net_exit ipt_exit_net(struct list_head *net_list) 393 { 394 tc_action_net_exit(net_list, act_ipt_ops.net_id); 395 } 396 397 static struct pernet_operations ipt_net_ops = { 398 .init = ipt_init_net, 399 .exit_batch = ipt_exit_net, 400 .id = &act_ipt_ops.net_id, 401 .size = sizeof(struct tc_action_net), 402 }; 403 404 static struct tc_action_ops act_xt_ops = { 405 .kind = "xt", 406 .id = TCA_ID_XT, 407 .owner = THIS_MODULE, 408 .act = tcf_ipt_act, 409 .dump = tcf_ipt_dump, 410 .cleanup = tcf_ipt_release, 411 .init = tcf_xt_init, 412 .size = sizeof(struct tcf_ipt), 413 }; 414 415 static __net_init int xt_init_net(struct net *net) 416 { 417 struct tc_action_net *tn = net_generic(net, act_xt_ops.net_id); 418 419 return tc_action_net_init(net, tn, &act_xt_ops); 420 } 421 422 static void __net_exit xt_exit_net(struct list_head *net_list) 423 { 424 tc_action_net_exit(net_list, act_xt_ops.net_id); 425 } 426 427 static struct pernet_operations xt_net_ops = { 428 .init = xt_init_net, 429 .exit_batch = xt_exit_net, 430 .id = &act_xt_ops.net_id, 431 .size = sizeof(struct tc_action_net), 432 }; 433 434 MODULE_AUTHOR("Jamal Hadi Salim(2002-13)"); 435 MODULE_DESCRIPTION("Iptables target actions"); 436 MODULE_LICENSE("GPL"); 437 MODULE_ALIAS("act_xt"); 438 439 static int __init ipt_init_module(void) 440 { 441 int ret1, ret2; 442 443 ret1 = tcf_register_action(&act_xt_ops, &xt_net_ops); 444 if (ret1 < 0) 445 pr_err("Failed to load xt action\n"); 446 447 ret2 = tcf_register_action(&act_ipt_ops, &ipt_net_ops); 448 if (ret2 < 0) 449 pr_err("Failed to load ipt action\n"); 450 451 if (ret1 < 0 && ret2 < 0) { 452 return ret1; 453 } else 454 return 0; 455 } 456 457 static void __exit ipt_cleanup_module(void) 458 { 459 tcf_unregister_action(&act_ipt_ops, &ipt_net_ops); 460 tcf_unregister_action(&act_xt_ops, &xt_net_ops); 461 } 462 463 module_init(ipt_init_module); 464 module_exit(ipt_cleanup_module); 465