| 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); |