net/sched/act_ipt.c

   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, 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         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);