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, 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);