net/netfilter/nft_compat.c

   1 /*
   2  * (C) 2012-2013 by Pablo Neira Ayuso <pablo@netfilter.org>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License version 2 as
   6  * published by the Free Software Foundation.
   7  *
   8  * This software has been sponsored by Sophos Astaro <http://www.sophos.com>
   9  */
  10
  11 #include <linux/kernel.h>
  12 #include <linux/init.h>
  13 #include <linux/module.h>
  14 #include <linux/netlink.h>
  15 #include <linux/netfilter.h>
  16 #include <linux/netfilter/nfnetlink.h>
  17 #include <linux/netfilter/nf_tables.h>
  18 #include <linux/netfilter/nf_tables_compat.h>
  19 #include <linux/netfilter/x_tables.h>
  20 #include <linux/netfilter_ipv4/ip_tables.h>
  21 #include <linux/netfilter_ipv6/ip6_tables.h>
  22 #include <asm/uaccess.h> /* for set_fs */
  23 #include <net/netfilter/nf_tables.h>
  24
  25 union nft_entry {
  26         struct ipt_entry e4;
  27         struct ip6t_entry e6;
  28 };
  29
  30 static inline void
  31 nft_compat_set_par(struct xt_action_param *par, void *xt, const void *xt_info)
  32 {
  33         par->target     = xt;
  34         par->targinfo   = xt_info;
  35         par->hotdrop    = false;
  36 }
  37
  38 static void nft_target_eval(const struct nft_expr *expr,
  39                             struct nft_data data[NFT_REG_MAX + 1],
  40                             const struct nft_pktinfo *pkt)
  41 {
  42         void *info = nft_expr_priv(expr);
  43         struct xt_target *target = expr->ops->data;
  44         struct sk_buff *skb = pkt->skb;
  45         int ret;
  46
  47         nft_compat_set_par((struct xt_action_param *)&pkt->xt, target, info);
  48
  49         ret = target->target(skb, &pkt->xt);
  50
  51         if (pkt->xt.hotdrop)
  52                 ret = NF_DROP;
  53
  54         switch(ret) {
  55         case XT_CONTINUE:
  56                 data[NFT_REG_VERDICT].verdict = NFT_CONTINUE;
  57                 break;
  58         default:
  59                 data[NFT_REG_VERDICT].verdict = ret;
  60                 break;
  61         }
  62         return;
  63 }
  64
  65 static const struct nla_policy nft_target_policy[NFTA_TARGET_MAX + 1] = {
  66         [NFTA_TARGET_NAME]      = { .type = NLA_NUL_STRING },
  67         [NFTA_TARGET_REV]       = { .type = NLA_U32 },
  68         [NFTA_TARGET_INFO]      = { .type = NLA_BINARY },
  69 };
  70
  71 static void
  72 nft_target_set_tgchk_param(struct xt_tgchk_param *par,
  73                            const struct nft_ctx *ctx,
  74                            struct xt_target *target, void *info,
  75                            union nft_entry *entry, u8 proto, bool inv)
  76 {
  77         par->net        = &init_net;
  78         par->table      = ctx->table->name;
  79         switch (ctx->afi->family) {
  80         case AF_INET:
  81                 entry->e4.ip.proto = proto;
  82                 entry->e4.ip.invflags = inv ? IPT_INV_PROTO : 0;
  83                 break;
  84         case AF_INET6:
  85                 entry->e6.ipv6.proto = proto;
  86                 entry->e6.ipv6.invflags = inv ? IP6T_INV_PROTO : 0;
  87                 break;
  88         }
  89         par->entryinfo  = entry;
  90         par->target     = target;
  91         par->targinfo   = info;
  92         if (ctx->chain->flags & NFT_BASE_CHAIN) {
  93                 const struct nft_base_chain *basechain =
  94                                                 nft_base_chain(ctx->chain);
  95                 const struct nf_hook_ops *ops = &basechain->ops[0];
  96
  97                 par->hook_mask = 1 << ops->hooknum;
  98         }
  99         par->family     = ctx->afi->family;
 100 }
 101
 102 static void target_compat_from_user(struct xt_target *t, void *in, void *out)
 103 {
 104         int pad;
 105
 106         memcpy(out, in, t->targetsize);
 107         pad = XT_ALIGN(t->targetsize) - t->targetsize;
 108         if (pad > 0)
 109                 memset(out + t->targetsize, 0, pad);
 110 }
 111
 112 static const struct nla_policy nft_rule_compat_policy[NFTA_RULE_COMPAT_MAX + 1] = {
 113         [NFTA_RULE_COMPAT_PROTO]        = { .type = NLA_U32 },
 114         [NFTA_RULE_COMPAT_FLAGS]        = { .type = NLA_U32 },
 115 };
 116
 117 static int nft_parse_compat(const struct nlattr *attr, u8 *proto, bool *inv)
 118 {
 119         struct nlattr *tb[NFTA_RULE_COMPAT_MAX+1];
 120         u32 flags;
 121         int err;
 122
 123         err = nla_parse_nested(tb, NFTA_RULE_COMPAT_MAX, attr,
 124                                nft_rule_compat_policy);
 125         if (err < 0)
 126                 return err;
 127
 128         if (!tb[NFTA_RULE_COMPAT_PROTO] || !tb[NFTA_RULE_COMPAT_FLAGS])
 129                 return -EINVAL;
 130
 131         flags = ntohl(nla_get_be32(tb[NFTA_RULE_COMPAT_FLAGS]));
 132         if (flags & ~NFT_RULE_COMPAT_F_MASK)
 133                 return -EINVAL;
 134         if (flags & NFT_RULE_COMPAT_F_INV)
 135                 *inv = true;
 136
 137         *proto = ntohl(nla_get_be32(tb[NFTA_RULE_COMPAT_PROTO]));
 138         return 0;
 139 }
 140
 141 static int
 142 nft_target_init(const struct nft_ctx *ctx, const struct nft_expr *expr,
 143                 const struct nlattr * const tb[])
 144 {
 145         void *info = nft_expr_priv(expr);
 146         struct xt_target *target = expr->ops->data;
 147         struct xt_tgchk_param par;
 148         size_t size = XT_ALIGN(nla_len(tb[NFTA_TARGET_INFO]));
 149         u8 proto = 0;
 150         bool inv = false;
 151         union nft_entry e = {};
 152         int ret;
 153
 154         target_compat_from_user(target, nla_data(tb[NFTA_TARGET_INFO]), info);
 155
 156         if (ctx->nla[NFTA_RULE_COMPAT]) {
 157                 ret = nft_parse_compat(ctx->nla[NFTA_RULE_COMPAT], &proto, &inv);
 158                 if (ret < 0)
 159                         goto err;
 160         }
 161
 162         nft_target_set_tgchk_param(&par, ctx, target, info, &e, proto, inv);
 163
 164         ret = xt_check_target(&par, size, proto, inv);
 165         if (ret < 0)
 166                 goto err;
 167
 168         /* The standard target cannot be used */
 169         if (target->target == NULL) {
 170                 ret = -EINVAL;
 171                 goto err;
 172         }
 173
 174         return 0;
 175 err:
 176         module_put(target->me);
 177         return ret;
 178 }
 179
 180 static void
 181 nft_target_destroy(const struct nft_ctx *ctx, const struct nft_expr *expr)
 182 {
 183         struct xt_target *target = expr->ops->data;
 184         void *info = nft_expr_priv(expr);
 185         struct xt_tgdtor_param par;
 186
 187         par.net = ctx->net;
 188         par.target = target;
 189         par.targinfo = info;
 190         par.family = ctx->afi->family;
 191         if (par.target->destroy != NULL)
 192                 par.target->destroy(&par);
 193
 194         module_put(target->me);
 195 }
 196
 197 static int nft_target_dump(struct sk_buff *skb, const struct nft_expr *expr)
 198 {
 199         const struct xt_target *target = expr->ops->data;
 200         void *info = nft_expr_priv(expr);
 201
 202         if (nla_put_string(skb, NFTA_TARGET_NAME, target->name) ||
 203             nla_put_be32(skb, NFTA_TARGET_REV, htonl(target->revision)) ||
 204             nla_put(skb, NFTA_TARGET_INFO, XT_ALIGN(target->targetsize), info))
 205                 goto nla_put_failure;
 206
 207         return 0;
 208
 209 nla_put_failure:
 210         return -1;
 211 }
 212
 213 static int nft_target_validate(const struct nft_ctx *ctx,
 214                                const struct nft_expr *expr,
 215                                const struct nft_data **data)
 216 {
 217         struct xt_target *target = expr->ops->data;
 218         unsigned int hook_mask = 0;
 219
 220         if (ctx->chain->flags & NFT_BASE_CHAIN) {
 221                 const struct nft_base_chain *basechain =
 222                                                 nft_base_chain(ctx->chain);
 223                 const struct nf_hook_ops *ops = &basechain->ops[0];
 224
 225                 hook_mask = 1 << ops->hooknum;
 226                 if (hook_mask & target->hooks)
 227                         return 0;
 228
 229                 /* This target is being called from an invalid chain */
 230                 return -EINVAL;
 231         }
 232         return 0;
 233 }
 234
 235 static void nft_match_eval(const struct nft_expr *expr,
 236                            struct nft_data data[NFT_REG_MAX + 1],
 237                            const struct nft_pktinfo *pkt)
 238 {
 239         void *info = nft_expr_priv(expr);
 240         struct xt_match *match = expr->ops->data;
 241         struct sk_buff *skb = pkt->skb;
 242         bool ret;
 243
 244         nft_compat_set_par((struct xt_action_param *)&pkt->xt, match, info);
 245
 246         ret = match->match(skb, (struct xt_action_param *)&pkt->xt);
 247
 248         if (pkt->xt.hotdrop) {
 249                 data[NFT_REG_VERDICT].verdict = NF_DROP;
 250                 return;
 251         }
 252
 253         switch(ret) {
 254         case true:
 255                 data[NFT_REG_VERDICT].verdict = NFT_CONTINUE;
 256                 break;
 257         case false:
 258                 data[NFT_REG_VERDICT].verdict = NFT_BREAK;
 259                 break;
 260         }
 261 }
 262
 263 static const struct nla_policy nft_match_policy[NFTA_MATCH_MAX + 1] = {
 264         [NFTA_MATCH_NAME]       = { .type = NLA_NUL_STRING },
 265         [NFTA_MATCH_REV]        = { .type = NLA_U32 },
 266         [NFTA_MATCH_INFO]       = { .type = NLA_BINARY },
 267 };
 268
 269 /* struct xt_mtchk_param and xt_tgchk_param look very similar */
 270 static void
 271 nft_match_set_mtchk_param(struct xt_mtchk_param *par, const struct nft_ctx *ctx,
 272                           struct xt_match *match, void *info,
 273                           union nft_entry *entry, u8 proto, bool inv)
 274 {
 275         par->net        = &init_net;
 276         par->table      = ctx->table->name;
 277         switch (ctx->afi->family) {
 278         case AF_INET:
 279                 entry->e4.ip.proto = proto;
 280                 entry->e4.ip.invflags = inv ? IPT_INV_PROTO : 0;
 281                 break;
 282         case AF_INET6:
 283                 entry->e6.ipv6.proto = proto;
 284                 entry->e6.ipv6.invflags = inv ? IP6T_INV_PROTO : 0;
 285                 break;
 286         }
 287         par->entryinfo  = entry;
 288         par->match      = match;
 289         par->matchinfo  = info;
 290         if (ctx->chain->flags & NFT_BASE_CHAIN) {
 291                 const struct nft_base_chain *basechain =
 292                                                 nft_base_chain(ctx->chain);
 293                 const struct nf_hook_ops *ops = &basechain->ops[0];
 294
 295                 par->hook_mask = 1 << ops->hooknum;
 296         }
 297         par->family     = ctx->afi->family;
 298 }
 299
 300 static void match_compat_from_user(struct xt_match *m, void *in, void *out)
 301 {
 302         int pad;
 303
 304         memcpy(out, in, m->matchsize);
 305         pad = XT_ALIGN(m->matchsize) - m->matchsize;
 306         if (pad > 0)
 307                 memset(out + m->matchsize, 0, pad);
 308 }
 309
 310 static int
 311 nft_match_init(const struct nft_ctx *ctx, const struct nft_expr *expr,
 312                 const struct nlattr * const tb[])
 313 {
 314         void *info = nft_expr_priv(expr);
 315         struct xt_match *match = expr->ops->data;
 316         struct xt_mtchk_param par;
 317         size_t size = XT_ALIGN(nla_len(tb[NFTA_MATCH_INFO]));
 318         u8 proto = 0;
 319         bool inv = false;
 320         union nft_entry e = {};
 321         int ret;
 322
 323         match_compat_from_user(match, nla_data(tb[NFTA_MATCH_INFO]), info);
 324
 325         if (ctx->nla[NFTA_RULE_COMPAT]) {
 326                 ret = nft_parse_compat(ctx->nla[NFTA_RULE_COMPAT], &proto, &inv);
 327                 if (ret < 0)
 328                         goto err;
 329         }
 330
 331         nft_match_set_mtchk_param(&par, ctx, match, info, &e, proto, inv);
 332
 333         ret = xt_check_match(&par, size, proto, inv);
 334         if (ret < 0)
 335                 goto err;
 336
 337         return 0;
 338 err:
 339         module_put(match->me);
 340         return ret;
 341 }
 342
 343 static void
 344 nft_match_destroy(const struct nft_ctx *ctx, const struct nft_expr *expr)
 345 {
 346         struct xt_match *match = expr->ops->data;
 347         void *info = nft_expr_priv(expr);
 348         struct xt_mtdtor_param par;
 349
 350         par.net = ctx->net;
 351         par.match = match;
 352         par.matchinfo = info;
 353         par.family = ctx->afi->family;
 354         if (par.match->destroy != NULL)
 355                 par.match->destroy(&par);
 356
 357         module_put(match->me);
 358 }
 359
 360 static int nft_match_dump(struct sk_buff *skb, const struct nft_expr *expr)
 361 {
 362         void *info = nft_expr_priv(expr);
 363         struct xt_match *match = expr->ops->data;
 364
 365         if (nla_put_string(skb, NFTA_MATCH_NAME, match->name) ||
 366             nla_put_be32(skb, NFTA_MATCH_REV, htonl(match->revision)) ||
 367             nla_put(skb, NFTA_MATCH_INFO, XT_ALIGN(match->matchsize), info))
 368                 goto nla_put_failure;
 369
 370         return 0;
 371
 372 nla_put_failure:
 373         return -1;
 374 }
 375
 376 static int nft_match_validate(const struct nft_ctx *ctx,
 377                               const struct nft_expr *expr,
 378                               const struct nft_data **data)
 379 {
 380         struct xt_match *match = expr->ops->data;
 381         unsigned int hook_mask = 0;
 382
 383         if (ctx->chain->flags & NFT_BASE_CHAIN) {
 384                 const struct nft_base_chain *basechain =
 385                                                 nft_base_chain(ctx->chain);
 386                 const struct nf_hook_ops *ops = &basechain->ops[0];
 387
 388                 hook_mask = 1 << ops->hooknum;
 389                 if (hook_mask & match->hooks)
 390                         return 0;
 391
 392                 /* This match is being called from an invalid chain */
 393                 return -EINVAL;
 394         }
 395         return 0;
 396 }
 397
 398 static int
 399 nfnl_compat_fill_info(struct sk_buff *skb, u32 portid, u32 seq, u32 type,
 400                       int event, u16 family, const char *name,
 401                       int rev, int target)
 402 {
 403         struct nlmsghdr *nlh;
 404         struct nfgenmsg *nfmsg;
 405         unsigned int flags = portid ? NLM_F_MULTI : 0;
 406
 407         event |= NFNL_SUBSYS_NFT_COMPAT << 8;
 408         nlh = nlmsg_put(skb, portid, seq, event, sizeof(*nfmsg), flags);
 409         if (nlh == NULL)
 410                 goto nlmsg_failure;
 411
 412         nfmsg = nlmsg_data(nlh);
 413         nfmsg->nfgen_family = family;
 414         nfmsg->version = NFNETLINK_V0;
 415         nfmsg->res_id = 0;
 416
 417         if (nla_put_string(skb, NFTA_COMPAT_NAME, name) ||
 418             nla_put_be32(skb, NFTA_COMPAT_REV, htonl(rev)) ||
 419             nla_put_be32(skb, NFTA_COMPAT_TYPE, htonl(target)))
 420                 goto nla_put_failure;
 421
 422         nlmsg_end(skb, nlh);
 423         return skb->len;
 424
 425 nlmsg_failure:
 426 nla_put_failure:
 427         nlmsg_cancel(skb, nlh);
 428         return -1;
 429 }
 430
 431 static int
 432 nfnl_compat_get(struct sock *nfnl, struct sk_buff *skb,
 433                 const struct nlmsghdr *nlh, const struct nlattr * const tb[])
 434 {
 435         int ret = 0, target;
 436         struct nfgenmsg *nfmsg;
 437         const char *fmt;
 438         const char *name;
 439         u32 rev;
 440         struct sk_buff *skb2;
 441
 442         if (tb[NFTA_COMPAT_NAME] == NULL ||
 443             tb[NFTA_COMPAT_REV] == NULL ||
 444             tb[NFTA_COMPAT_TYPE] == NULL)
 445                 return -EINVAL;
 446
 447         name = nla_data(tb[NFTA_COMPAT_NAME]);
 448         rev = ntohl(nla_get_be32(tb[NFTA_COMPAT_REV]));
 449         target = ntohl(nla_get_be32(tb[NFTA_COMPAT_TYPE]));
 450
 451         nfmsg = nlmsg_data(nlh);
 452
 453         switch(nfmsg->nfgen_family) {
 454         case AF_INET:
 455                 fmt = "ipt_%s";
 456                 break;
 457         case AF_INET6:
 458                 fmt = "ip6t_%s";
 459                 break;
 460         default:
 461                 pr_err("nft_compat: unsupported protocol %d\n",
 462                         nfmsg->nfgen_family);
 463                 return -EINVAL;
 464         }
 465
 466         try_then_request_module(xt_find_revision(nfmsg->nfgen_family, name,
 467                                                  rev, target, &ret),
 468                                                  fmt, name);
 469
 470         if (ret < 0)
 471                 return ret;
 472
 473         skb2 = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 474         if (skb2 == NULL)
 475                 return -ENOMEM;
 476
 477         /* include the best revision for this extension in the message */
 478         if (nfnl_compat_fill_info(skb2, NETLINK_CB(skb).portid,
 479                                   nlh->nlmsg_seq,
 480                                   NFNL_MSG_TYPE(nlh->nlmsg_type),
 481                                   NFNL_MSG_COMPAT_GET,
 482                                   nfmsg->nfgen_family,
 483                                   name, ret, target) <= 0) {
 484                 kfree_skb(skb2);
 485                 return -ENOSPC;
 486         }
 487
 488         ret = netlink_unicast(nfnl, skb2, NETLINK_CB(skb).portid,
 489                                 MSG_DONTWAIT);
 490         if (ret > 0)
 491                 ret = 0;
 492
 493         return ret == -EAGAIN ? -ENOBUFS : ret;
 494 }
 495
 496 static const struct nla_policy nfnl_compat_policy_get[NFTA_COMPAT_MAX+1] = {
 497         [NFTA_COMPAT_NAME]      = { .type = NLA_NUL_STRING,
 498                                     .len = NFT_COMPAT_NAME_MAX-1 },
 499         [NFTA_COMPAT_REV]       = { .type = NLA_U32 },
 500         [NFTA_COMPAT_TYPE]      = { .type = NLA_U32 },
 501 };
 502
 503 static const struct nfnl_callback nfnl_nft_compat_cb[NFNL_MSG_COMPAT_MAX] = {
 504         [NFNL_MSG_COMPAT_GET]           = { .call = nfnl_compat_get,
 505                                             .attr_count = NFTA_COMPAT_MAX,
 506                                             .policy = nfnl_compat_policy_get },
 507 };
 508
 509 static const struct nfnetlink_subsystem nfnl_compat_subsys = {
 510         .name           = "nft-compat",
 511         .subsys_id      = NFNL_SUBSYS_NFT_COMPAT,
 512         .cb_count       = NFNL_MSG_COMPAT_MAX,
 513         .cb             = nfnl_nft_compat_cb,
 514 };
 515
 516 static LIST_HEAD(nft_match_list);
 517
 518 struct nft_xt {
 519         struct list_head        head;
 520         struct nft_expr_ops     ops;
 521 };
 522
 523 static struct nft_expr_type nft_match_type;
 524
 525 static const struct nft_expr_ops *
 526 nft_match_select_ops(const struct nft_ctx *ctx,
 527                      const struct nlattr * const tb[])
 528 {
 529         struct nft_xt *nft_match;
 530         struct xt_match *match;
 531         char *mt_name;
 532         __u32 rev, family;
 533
 534         if (tb[NFTA_MATCH_NAME] == NULL ||
 535             tb[NFTA_MATCH_REV] == NULL ||
 536             tb[NFTA_MATCH_INFO] == NULL)
 537                 return ERR_PTR(-EINVAL);
 538
 539         mt_name = nla_data(tb[NFTA_MATCH_NAME]);
 540         rev = ntohl(nla_get_be32(tb[NFTA_MATCH_REV]));
 541         family = ctx->afi->family;
 542
 543         /* Re-use the existing match if it's already loaded. */
 544         list_for_each_entry(nft_match, &nft_match_list, head) {
 545                 struct xt_match *match = nft_match->ops.data;
 546
 547                 if (strcmp(match->name, mt_name) == 0 &&
 548                     match->revision == rev && match->family == family)
 549                         return &nft_match->ops;
 550         }
 551
 552         match = xt_request_find_match(family, mt_name, rev);
 553         if (IS_ERR(match))
 554                 return ERR_PTR(-ENOENT);
 555
 556         /* This is the first time we use this match, allocate operations */
 557         nft_match = kzalloc(sizeof(struct nft_xt), GFP_KERNEL);
 558         if (nft_match == NULL)
 559                 return ERR_PTR(-ENOMEM);
 560
 561         nft_match->ops.type = &nft_match_type;
 562         nft_match->ops.size = NFT_EXPR_SIZE(XT_ALIGN(match->matchsize));
 563         nft_match->ops.eval = nft_match_eval;
 564         nft_match->ops.init = nft_match_init;
 565         nft_match->ops.destroy = nft_match_destroy;
 566         nft_match->ops.dump = nft_match_dump;
 567         nft_match->ops.validate = nft_match_validate;
 568         nft_match->ops.data = match;
 569
 570         list_add(&nft_match->head, &nft_match_list);
 571
 572         return &nft_match->ops;
 573 }
 574
 575 static void nft_match_release(void)
 576 {
 577         struct nft_xt *nft_match, *tmp;
 578
 579         list_for_each_entry_safe(nft_match, tmp, &nft_match_list, head)
 580                 kfree(nft_match);
 581 }
 582
 583 static struct nft_expr_type nft_match_type __read_mostly = {
 584         .name           = "match",
 585         .select_ops     = nft_match_select_ops,
 586         .policy         = nft_match_policy,
 587         .maxattr        = NFTA_MATCH_MAX,
 588         .owner          = THIS_MODULE,
 589 };
 590
 591 static LIST_HEAD(nft_target_list);
 592
 593 static struct nft_expr_type nft_target_type;
 594
 595 static const struct nft_expr_ops *
 596 nft_target_select_ops(const struct nft_ctx *ctx,
 597                       const struct nlattr * const tb[])
 598 {
 599         struct nft_xt *nft_target;
 600         struct xt_target *target;
 601         char *tg_name;
 602         __u32 rev, family;
 603
 604         if (tb[NFTA_TARGET_NAME] == NULL ||
 605             tb[NFTA_TARGET_REV] == NULL ||
 606             tb[NFTA_TARGET_INFO] == NULL)
 607                 return ERR_PTR(-EINVAL);
 608
 609         tg_name = nla_data(tb[NFTA_TARGET_NAME]);
 610         rev = ntohl(nla_get_be32(tb[NFTA_TARGET_REV]));
 611         family = ctx->afi->family;
 612
 613         /* Re-use the existing target if it's already loaded. */
 614         list_for_each_entry(nft_target, &nft_match_list, head) {
 615                 struct xt_target *target = nft_target->ops.data;
 616
 617                 if (strcmp(target->name, tg_name) == 0 &&
 618                     target->revision == rev && target->family == family)
 619                         return &nft_target->ops;
 620         }
 621
 622         target = xt_request_find_target(family, tg_name, rev);
 623         if (IS_ERR(target))
 624                 return ERR_PTR(-ENOENT);
 625
 626         /* This is the first time we use this target, allocate operations */
 627         nft_target = kzalloc(sizeof(struct nft_xt), GFP_KERNEL);
 628         if (nft_target == NULL)
 629                 return ERR_PTR(-ENOMEM);
 630
 631         nft_target->ops.type = &nft_target_type;
 632         nft_target->ops.size = NFT_EXPR_SIZE(XT_ALIGN(target->targetsize));
 633         nft_target->ops.eval = nft_target_eval;
 634         nft_target->ops.init = nft_target_init;
 635         nft_target->ops.destroy = nft_target_destroy;
 636         nft_target->ops.dump = nft_target_dump;
 637         nft_target->ops.validate = nft_target_validate;
 638         nft_target->ops.data = target;
 639
 640         list_add(&nft_target->head, &nft_target_list);
 641
 642         return &nft_target->ops;
 643 }
 644
 645 static void nft_target_release(void)
 646 {
 647         struct nft_xt *nft_target, *tmp;
 648
 649         list_for_each_entry_safe(nft_target, tmp, &nft_target_list, head)
 650                 kfree(nft_target);
 651 }
 652
 653 static struct nft_expr_type nft_target_type __read_mostly = {
 654         .name           = "target",
 655         .select_ops     = nft_target_select_ops,
 656         .policy         = nft_target_policy,
 657         .maxattr        = NFTA_TARGET_MAX,
 658         .owner          = THIS_MODULE,
 659 };
 660
 661 static int __init nft_compat_module_init(void)
 662 {
 663         int ret;
 664
 665         ret = nft_register_expr(&nft_match_type);
 666         if (ret < 0)
 667                 return ret;
 668
 669         ret = nft_register_expr(&nft_target_type);
 670         if (ret < 0)
 671                 goto err_match;
 672
 673         ret = nfnetlink_subsys_register(&nfnl_compat_subsys);
 674         if (ret < 0) {
 675                 pr_err("nft_compat: cannot register with nfnetlink.\n");
 676                 goto err_target;
 677         }
 678
 679         pr_info("nf_tables_compat: (c) 2012 Pablo Neira Ayuso <pablo@netfilter.org>\n");
 680
 681         return ret;
 682
 683 err_target:
 684         nft_unregister_expr(&nft_target_type);
 685 err_match:
 686         nft_unregister_expr(&nft_match_type);
 687         return ret;
 688 }
 689
 690 static void __exit nft_compat_module_exit(void)
 691 {
 692         nfnetlink_subsys_unregister(&nfnl_compat_subsys);
 693         nft_unregister_expr(&nft_target_type);
 694         nft_unregister_expr(&nft_match_type);
 695         nft_match_release();
 696         nft_target_release();
 697 }
 698
 699 MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_NFT_COMPAT);
 700
 701 module_init(nft_compat_module_init);
 702 module_exit(nft_compat_module_exit);
 703
 704 MODULE_LICENSE("GPL");
 705 MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
 706 MODULE_ALIAS_NFT_EXPR("match");
 707 MODULE_ALIAS_NFT_EXPR("target");