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