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 <linux/netfilter_bridge/ebtables.h>
  23 #include <linux/netfilter_arp/arp_tables.h>
  24 #include <net/netfilter/nf_tables.h>
  25
  26 struct nft_xt {
  27         struct list_head        head;
  28         struct nft_expr_ops     ops;
  29         unsigned int            refcnt;
  30 };
  31
  32 static void nft_xt_put(struct nft_xt *xt)
  33 {
  34         if (--xt->refcnt == 0) {
  35                 list_del(&xt->head);
  36                 kfree(xt);
  37         }
  38 }
  39
  40 static int nft_compat_chain_validate_dependency(const char *tablename,
  41                                                 const struct nft_chain *chain)
  42 {
  43         const struct nft_base_chain *basechain;
  44
  45         if (!tablename ||
  46             !nft_is_base_chain(chain))
  47                 return 0;
  48
  49         basechain = nft_base_chain(chain);
  50         if (strcmp(tablename, "nat") == 0 &&
  51             basechain->type->type != NFT_CHAIN_T_NAT)
  52                 return -EINVAL;
  53
  54         return 0;
  55 }
  56
  57 union nft_entry {
  58         struct ipt_entry e4;
  59         struct ip6t_entry e6;
  60         struct ebt_entry ebt;
  61         struct arpt_entry arp;
  62 };
  63
  64 static inline void
  65 nft_compat_set_par(struct xt_action_param *par, void *xt, const void *xt_info)
  66 {
  67         par->target     = xt;
  68         par->targinfo   = xt_info;
  69         par->hotdrop    = false;
  70 }
  71
  72 static void nft_target_eval_xt(const struct nft_expr *expr,
  73                                struct nft_regs *regs,
  74                                const struct nft_pktinfo *pkt)
  75 {
  76         void *info = nft_expr_priv(expr);
  77         struct xt_target *target = expr->ops->data;
  78         struct sk_buff *skb = pkt->skb;
  79         int ret;
  80
  81         nft_compat_set_par((struct xt_action_param *)&pkt->xt, target, info);
  82
  83         ret = target->target(skb, &pkt->xt);
  84
  85         if (pkt->xt.hotdrop)
  86                 ret = NF_DROP;
  87
  88         switch (ret) {
  89         case XT_CONTINUE:
  90                 regs->verdict.code = NFT_CONTINUE;
  91                 break;
  92         default:
  93                 regs->verdict.code = ret;
  94                 break;
  95         }
  96 }
  97
  98 static void nft_target_eval_bridge(const struct nft_expr *expr,
  99                                    struct nft_regs *regs,
 100                                    const struct nft_pktinfo *pkt)
 101 {
 102         void *info = nft_expr_priv(expr);
 103         struct xt_target *target = expr->ops->data;
 104         struct sk_buff *skb = pkt->skb;
 105         int ret;
 106
 107         nft_compat_set_par((struct xt_action_param *)&pkt->xt, target, info);
 108
 109         ret = target->target(skb, &pkt->xt);
 110
 111         if (pkt->xt.hotdrop)
 112                 ret = NF_DROP;
 113
 114         switch (ret) {
 115         case EBT_ACCEPT:
 116                 regs->verdict.code = NF_ACCEPT;
 117                 break;
 118         case EBT_DROP:
 119                 regs->verdict.code = NF_DROP;
 120                 break;
 121         case EBT_CONTINUE:
 122                 regs->verdict.code = NFT_CONTINUE;
 123                 break;
 124         case EBT_RETURN:
 125                 regs->verdict.code = NFT_RETURN;
 126                 break;
 127         default:
 128                 regs->verdict.code = ret;
 129                 break;
 130         }
 131 }
 132
 133 static const struct nla_policy nft_target_policy[NFTA_TARGET_MAX + 1] = {
 134         [NFTA_TARGET_NAME]      = { .type = NLA_NUL_STRING },
 135         [NFTA_TARGET_REV]       = { .type = NLA_U32 },
 136         [NFTA_TARGET_INFO]      = { .type = NLA_BINARY },
 137 };
 138
 139 static void
 140 nft_target_set_tgchk_param(struct xt_tgchk_param *par,
 141                            const struct nft_ctx *ctx,
 142                            struct xt_target *target, void *info,
 143                            union nft_entry *entry, u16 proto, bool inv)
 144 {
 145         par->net        = ctx->net;
 146         par->table      = ctx->table->name;
 147         switch (ctx->afi->family) {
 148         case AF_INET:
 149                 entry->e4.ip.proto = proto;
 150                 entry->e4.ip.invflags = inv ? IPT_INV_PROTO : 0;
 151                 break;
 152         case AF_INET6:
 153                 if (proto)
 154                         entry->e6.ipv6.flags |= IP6T_F_PROTO;
 155
 156                 entry->e6.ipv6.proto = proto;
 157                 entry->e6.ipv6.invflags = inv ? IP6T_INV_PROTO : 0;
 158                 break;
 159         case NFPROTO_BRIDGE:
 160                 entry->ebt.ethproto = (__force __be16)proto;
 161                 entry->ebt.invflags = inv ? EBT_IPROTO : 0;
 162                 break;
 163         case NFPROTO_ARP:
 164                 break;
 165         }
 166         par->entryinfo  = entry;
 167         par->target     = target;
 168         par->targinfo   = info;
 169         if (nft_is_base_chain(ctx->chain)) {
 170                 const struct nft_base_chain *basechain =
 171                                                 nft_base_chain(ctx->chain);
 172                 const struct nf_hook_ops *ops = &basechain->ops[0];
 173
 174                 par->hook_mask = 1 << ops->hooknum;
 175         } else {
 176                 par->hook_mask = 0;
 177         }
 178         par->family     = ctx->afi->family;
 179         par->nft_compat = true;
 180 }
 181
 182 static void target_compat_from_user(struct xt_target *t, void *in, void *out)
 183 {
 184         int pad;
 185
 186         memcpy(out, in, t->targetsize);
 187         pad = XT_ALIGN(t->targetsize) - t->targetsize;
 188         if (pad > 0)
 189                 memset(out + t->targetsize, 0, pad);
 190 }
 191
 192 static const struct nla_policy nft_rule_compat_policy[NFTA_RULE_COMPAT_MAX + 1] = {
 193         [NFTA_RULE_COMPAT_PROTO]        = { .type = NLA_U32 },
 194         [NFTA_RULE_COMPAT_FLAGS]        = { .type = NLA_U32 },
 195 };
 196
 197 static int nft_parse_compat(const struct nlattr *attr, u16 *proto, bool *inv)
 198 {
 199         struct nlattr *tb[NFTA_RULE_COMPAT_MAX+1];
 200         u32 flags;
 201         int err;
 202
 203         err = nla_parse_nested(tb, NFTA_RULE_COMPAT_MAX, attr,
 204                                nft_rule_compat_policy, NULL);
 205         if (err < 0)
 206                 return err;
 207
 208         if (!tb[NFTA_RULE_COMPAT_PROTO] || !tb[NFTA_RULE_COMPAT_FLAGS])
 209                 return -EINVAL;
 210
 211         flags = ntohl(nla_get_be32(tb[NFTA_RULE_COMPAT_FLAGS]));
 212         if (flags & ~NFT_RULE_COMPAT_F_MASK)
 213                 return -EINVAL;
 214         if (flags & NFT_RULE_COMPAT_F_INV)
 215                 *inv = true;
 216
 217         *proto = ntohl(nla_get_be32(tb[NFTA_RULE_COMPAT_PROTO]));
 218         return 0;
 219 }
 220
 221 static int
 222 nft_target_init(const struct nft_ctx *ctx, const struct nft_expr *expr,
 223                 const struct nlattr * const tb[])
 224 {
 225         void *info = nft_expr_priv(expr);
 226         struct xt_target *target = expr->ops->data;
 227         struct xt_tgchk_param par;
 228         size_t size = XT_ALIGN(nla_len(tb[NFTA_TARGET_INFO]));
 229         u16 proto = 0;
 230         bool inv = false;
 231         union nft_entry e = {};
 232         int ret;
 233
 234         target_compat_from_user(target, nla_data(tb[NFTA_TARGET_INFO]), info);
 235
 236         if (ctx->nla[NFTA_RULE_COMPAT]) {
 237                 ret = nft_parse_compat(ctx->nla[NFTA_RULE_COMPAT], &proto, &inv);
 238                 if (ret < 0)
 239                         goto err;
 240         }
 241
 242         nft_target_set_tgchk_param(&par, ctx, target, info, &e, proto, inv);
 243
 244         ret = xt_check_target(&par, size, proto, inv);
 245         if (ret < 0)
 246                 goto err;
 247
 248         /* The standard target cannot be used */
 249         if (target->target == NULL) {
 250                 ret = -EINVAL;
 251                 goto err;
 252         }
 253
 254         return 0;
 255 err:
 256         module_put(target->me);
 257         return ret;
 258 }
 259
 260 static void
 261 nft_target_destroy(const struct nft_ctx *ctx, const struct nft_expr *expr)
 262 {
 263         struct xt_target *target = expr->ops->data;
 264         void *info = nft_expr_priv(expr);
 265         struct xt_tgdtor_param par;
 266
 267         par.net = ctx->net;
 268         par.target = target;
 269         par.targinfo = info;
 270         par.family = ctx->afi->family;
 271         if (par.target->destroy != NULL)
 272                 par.target->destroy(&par);
 273
 274         nft_xt_put(container_of(expr->ops, struct nft_xt, ops));
 275         module_put(target->me);
 276 }
 277
 278 static int nft_target_dump(struct sk_buff *skb, const struct nft_expr *expr)
 279 {
 280         const struct xt_target *target = expr->ops->data;
 281         void *info = nft_expr_priv(expr);
 282
 283         if (nla_put_string(skb, NFTA_TARGET_NAME, target->name) ||
 284             nla_put_be32(skb, NFTA_TARGET_REV, htonl(target->revision)) ||
 285             nla_put(skb, NFTA_TARGET_INFO, XT_ALIGN(target->targetsize), info))
 286                 goto nla_put_failure;
 287
 288         return 0;
 289
 290 nla_put_failure:
 291         return -1;
 292 }
 293
 294 static int nft_target_validate(const struct nft_ctx *ctx,
 295                                const struct nft_expr *expr,
 296                                const struct nft_data **data)
 297 {
 298         struct xt_target *target = expr->ops->data;
 299         unsigned int hook_mask = 0;
 300         int ret;
 301
 302         if (nft_is_base_chain(ctx->chain)) {
 303                 const struct nft_base_chain *basechain =
 304                                                 nft_base_chain(ctx->chain);
 305                 const struct nf_hook_ops *ops = &basechain->ops[0];
 306
 307                 hook_mask = 1 << ops->hooknum;
 308                 if (!(hook_mask & target->hooks))
 309                         return -EINVAL;
 310
 311                 ret = nft_compat_chain_validate_dependency(target->table,
 312                                                            ctx->chain);
 313                 if (ret < 0)
 314                         return ret;
 315         }
 316         return 0;
 317 }
 318
 319 static void nft_match_eval(const struct nft_expr *expr,
 320                            struct nft_regs *regs,
 321                            const struct nft_pktinfo *pkt)
 322 {
 323         void *info = nft_expr_priv(expr);
 324         struct xt_match *match = expr->ops->data;
 325         struct sk_buff *skb = pkt->skb;
 326         bool ret;
 327
 328         nft_compat_set_par((struct xt_action_param *)&pkt->xt, match, info);
 329
 330         ret = match->match(skb, (struct xt_action_param *)&pkt->xt);
 331
 332         if (pkt->xt.hotdrop) {
 333                 regs->verdict.code = NF_DROP;
 334                 return;
 335         }
 336
 337         switch (ret ? 1 : 0) {
 338         case 1:
 339                 regs->verdict.code = NFT_CONTINUE;
 340                 break;
 341         case 0:
 342                 regs->verdict.code = NFT_BREAK;
 343                 break;
 344         }
 345 }
 346
 347 static const struct nla_policy nft_match_policy[NFTA_MATCH_MAX + 1] = {
 348         [NFTA_MATCH_NAME]       = { .type = NLA_NUL_STRING },
 349         [NFTA_MATCH_REV]        = { .type = NLA_U32 },
 350         [NFTA_MATCH_INFO]       = { .type = NLA_BINARY },
 351 };
 352
 353 /* struct xt_mtchk_param and xt_tgchk_param look very similar */
 354 static void
 355 nft_match_set_mtchk_param(struct xt_mtchk_param *par, const struct nft_ctx *ctx,
 356                           struct xt_match *match, void *info,
 357                           union nft_entry *entry, u16 proto, bool inv)
 358 {
 359         par->net        = ctx->net;
 360         par->table      = ctx->table->name;
 361         switch (ctx->afi->family) {
 362         case AF_INET:
 363                 entry->e4.ip.proto = proto;
 364                 entry->e4.ip.invflags = inv ? IPT_INV_PROTO : 0;
 365                 break;
 366         case AF_INET6:
 367                 if (proto)
 368                         entry->e6.ipv6.flags |= IP6T_F_PROTO;
 369
 370                 entry->e6.ipv6.proto = proto;
 371                 entry->e6.ipv6.invflags = inv ? IP6T_INV_PROTO : 0;
 372                 break;
 373         case NFPROTO_BRIDGE:
 374                 entry->ebt.ethproto = (__force __be16)proto;
 375                 entry->ebt.invflags = inv ? EBT_IPROTO : 0;
 376                 break;
 377         case NFPROTO_ARP:
 378                 break;
 379         }
 380         par->entryinfo  = entry;
 381         par->match      = match;
 382         par->matchinfo  = info;
 383         if (nft_is_base_chain(ctx->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                 par->hook_mask = 1 << ops->hooknum;
 389         } else {
 390                 par->hook_mask = 0;
 391         }
 392         par->family     = ctx->afi->family;
 393         par->nft_compat = true;
 394 }
 395
 396 static void match_compat_from_user(struct xt_match *m, void *in, void *out)
 397 {
 398         int pad;
 399
 400         memcpy(out, in, m->matchsize);
 401         pad = XT_ALIGN(m->matchsize) - m->matchsize;
 402         if (pad > 0)
 403                 memset(out + m->matchsize, 0, pad);
 404 }
 405
 406 static int
 407 nft_match_init(const struct nft_ctx *ctx, const struct nft_expr *expr,
 408                 const struct nlattr * const tb[])
 409 {
 410         void *info = nft_expr_priv(expr);
 411         struct xt_match *match = expr->ops->data;
 412         struct xt_mtchk_param par;
 413         size_t size = XT_ALIGN(nla_len(tb[NFTA_MATCH_INFO]));
 414         u16 proto = 0;
 415         bool inv = false;
 416         union nft_entry e = {};
 417         int ret;
 418
 419         match_compat_from_user(match, nla_data(tb[NFTA_MATCH_INFO]), info);
 420
 421         if (ctx->nla[NFTA_RULE_COMPAT]) {
 422                 ret = nft_parse_compat(ctx->nla[NFTA_RULE_COMPAT], &proto, &inv);
 423                 if (ret < 0)
 424                         goto err;
 425         }
 426
 427         nft_match_set_mtchk_param(&par, ctx, match, info, &e, proto, inv);
 428
 429         ret = xt_check_match(&par, size, proto, inv);
 430         if (ret < 0)
 431                 goto err;
 432
 433         return 0;
 434 err:
 435         module_put(match->me);
 436         return ret;
 437 }
 438
 439 static void
 440 nft_match_destroy(const struct nft_ctx *ctx, const struct nft_expr *expr)
 441 {
 442         struct xt_match *match = expr->ops->data;
 443         void *info = nft_expr_priv(expr);
 444         struct xt_mtdtor_param par;
 445
 446         par.net = ctx->net;
 447         par.match = match;
 448         par.matchinfo = info;
 449         par.family = ctx->afi->family;
 450         if (par.match->destroy != NULL)
 451                 par.match->destroy(&par);
 452
 453         nft_xt_put(container_of(expr->ops, struct nft_xt, ops));
 454         module_put(match->me);
 455 }
 456
 457 static int nft_match_dump(struct sk_buff *skb, const struct nft_expr *expr)
 458 {
 459         void *info = nft_expr_priv(expr);
 460         struct xt_match *match = expr->ops->data;
 461
 462         if (nla_put_string(skb, NFTA_MATCH_NAME, match->name) ||
 463             nla_put_be32(skb, NFTA_MATCH_REV, htonl(match->revision)) ||
 464             nla_put(skb, NFTA_MATCH_INFO, XT_ALIGN(match->matchsize), info))
 465                 goto nla_put_failure;
 466
 467         return 0;
 468
 469 nla_put_failure:
 470         return -1;
 471 }
 472
 473 static int nft_match_validate(const struct nft_ctx *ctx,
 474                               const struct nft_expr *expr,
 475                               const struct nft_data **data)
 476 {
 477         struct xt_match *match = expr->ops->data;
 478         unsigned int hook_mask = 0;
 479         int ret;
 480
 481         if (nft_is_base_chain(ctx->chain)) {
 482                 const struct nft_base_chain *basechain =
 483                                                 nft_base_chain(ctx->chain);
 484                 const struct nf_hook_ops *ops = &basechain->ops[0];
 485
 486                 hook_mask = 1 << ops->hooknum;
 487                 if (!(hook_mask & match->hooks))
 488                         return -EINVAL;
 489
 490                 ret = nft_compat_chain_validate_dependency(match->table,
 491                                                            ctx->chain);
 492                 if (ret < 0)
 493                         return ret;
 494         }
 495         return 0;
 496 }
 497
 498 static int
 499 nfnl_compat_fill_info(struct sk_buff *skb, u32 portid, u32 seq, u32 type,
 500                       int event, u16 family, const char *name,
 501                       int rev, int target)
 502 {
 503         struct nlmsghdr *nlh;
 504         struct nfgenmsg *nfmsg;
 505         unsigned int flags = portid ? NLM_F_MULTI : 0;
 506
 507         event = nfnl_msg_type(NFNL_SUBSYS_NFT_COMPAT, event);
 508         nlh = nlmsg_put(skb, portid, seq, event, sizeof(*nfmsg), flags);
 509         if (nlh == NULL)
 510                 goto nlmsg_failure;
 511
 512         nfmsg = nlmsg_data(nlh);
 513         nfmsg->nfgen_family = family;
 514         nfmsg->version = NFNETLINK_V0;
 515         nfmsg->res_id = 0;
 516
 517         if (nla_put_string(skb, NFTA_COMPAT_NAME, name) ||
 518             nla_put_be32(skb, NFTA_COMPAT_REV, htonl(rev)) ||
 519             nla_put_be32(skb, NFTA_COMPAT_TYPE, htonl(target)))
 520                 goto nla_put_failure;
 521
 522         nlmsg_end(skb, nlh);
 523         return skb->len;
 524
 525 nlmsg_failure:
 526 nla_put_failure:
 527         nlmsg_cancel(skb, nlh);
 528         return -1;
 529 }
 530
 531 static int nfnl_compat_get(struct net *net, struct sock *nfnl,
 532                            struct sk_buff *skb, const struct nlmsghdr *nlh,
 533                            const struct nlattr * const tb[],
 534                            struct netlink_ext_ack *extack)
 535 {
 536         int ret = 0, target;
 537         struct nfgenmsg *nfmsg;
 538         const char *fmt;
 539         const char *name;
 540         u32 rev;
 541         struct sk_buff *skb2;
 542
 543         if (tb[NFTA_COMPAT_NAME] == NULL ||
 544             tb[NFTA_COMPAT_REV] == NULL ||
 545             tb[NFTA_COMPAT_TYPE] == NULL)
 546                 return -EINVAL;
 547
 548         name = nla_data(tb[NFTA_COMPAT_NAME]);
 549         rev = ntohl(nla_get_be32(tb[NFTA_COMPAT_REV]));
 550         target = ntohl(nla_get_be32(tb[NFTA_COMPAT_TYPE]));
 551
 552         nfmsg = nlmsg_data(nlh);
 553
 554         switch(nfmsg->nfgen_family) {
 555         case AF_INET:
 556                 fmt = "ipt_%s";
 557                 break;
 558         case AF_INET6:
 559                 fmt = "ip6t_%s";
 560                 break;
 561         case NFPROTO_BRIDGE:
 562                 fmt = "ebt_%s";
 563                 break;
 564         case NFPROTO_ARP:
 565                 fmt = "arpt_%s";
 566                 break;
 567         default:
 568                 pr_err("nft_compat: unsupported protocol %d\n",
 569                         nfmsg->nfgen_family);
 570                 return -EINVAL;
 571         }
 572
 573         try_then_request_module(xt_find_revision(nfmsg->nfgen_family, name,
 574                                                  rev, target, &ret),
 575                                                  fmt, name);
 576
 577         if (ret < 0)
 578                 return ret;
 579
 580         skb2 = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 581         if (skb2 == NULL)
 582                 return -ENOMEM;
 583
 584         /* include the best revision for this extension in the message */
 585         if (nfnl_compat_fill_info(skb2, NETLINK_CB(skb).portid,
 586                                   nlh->nlmsg_seq,
 587                                   NFNL_MSG_TYPE(nlh->nlmsg_type),
 588                                   NFNL_MSG_COMPAT_GET,
 589                                   nfmsg->nfgen_family,
 590                                   name, ret, target) <= 0) {
 591                 kfree_skb(skb2);
 592                 return -ENOSPC;
 593         }
 594
 595         ret = netlink_unicast(nfnl, skb2, NETLINK_CB(skb).portid,
 596                                 MSG_DONTWAIT);
 597         if (ret > 0)
 598                 ret = 0;
 599
 600         return ret == -EAGAIN ? -ENOBUFS : ret;
 601 }
 602
 603 static const struct nla_policy nfnl_compat_policy_get[NFTA_COMPAT_MAX+1] = {
 604         [NFTA_COMPAT_NAME]      = { .type = NLA_NUL_STRING,
 605                                     .len = NFT_COMPAT_NAME_MAX-1 },
 606         [NFTA_COMPAT_REV]       = { .type = NLA_U32 },
 607         [NFTA_COMPAT_TYPE]      = { .type = NLA_U32 },
 608 };
 609
 610 static const struct nfnl_callback nfnl_nft_compat_cb[NFNL_MSG_COMPAT_MAX] = {
 611         [NFNL_MSG_COMPAT_GET]           = { .call = nfnl_compat_get,
 612                                             .attr_count = NFTA_COMPAT_MAX,
 613                                             .policy = nfnl_compat_policy_get },
 614 };
 615
 616 static const struct nfnetlink_subsystem nfnl_compat_subsys = {
 617         .name           = "nft-compat",
 618         .subsys_id      = NFNL_SUBSYS_NFT_COMPAT,
 619         .cb_count       = NFNL_MSG_COMPAT_MAX,
 620         .cb             = nfnl_nft_compat_cb,
 621 };
 622
 623 static LIST_HEAD(nft_match_list);
 624
 625 static struct nft_expr_type nft_match_type;
 626
 627 static bool nft_match_cmp(const struct xt_match *match,
 628                           const char *name, u32 rev, u32 family)
 629 {
 630         return strcmp(match->name, name) == 0 && match->revision == rev &&
 631                (match->family == NFPROTO_UNSPEC || match->family == family);
 632 }
 633
 634 static const struct nft_expr_ops *
 635 nft_match_select_ops(const struct nft_ctx *ctx,
 636                      const struct nlattr * const tb[])
 637 {
 638         struct nft_xt *nft_match;
 639         struct xt_match *match;
 640         char *mt_name;
 641         u32 rev, family;
 642         int err;
 643
 644         if (tb[NFTA_MATCH_NAME] == NULL ||
 645             tb[NFTA_MATCH_REV] == NULL ||
 646             tb[NFTA_MATCH_INFO] == NULL)
 647                 return ERR_PTR(-EINVAL);
 648
 649         mt_name = nla_data(tb[NFTA_MATCH_NAME]);
 650         rev = ntohl(nla_get_be32(tb[NFTA_MATCH_REV]));
 651         family = ctx->afi->family;
 652
 653         /* Re-use the existing match if it's already loaded. */
 654         list_for_each_entry(nft_match, &nft_match_list, head) {
 655                 struct xt_match *match = nft_match->ops.data;
 656
 657                 if (nft_match_cmp(match, mt_name, rev, family)) {
 658                         if (!try_module_get(match->me))
 659                                 return ERR_PTR(-ENOENT);
 660
 661                         nft_match->refcnt++;
 662                         return &nft_match->ops;
 663                 }
 664         }
 665
 666         match = xt_request_find_match(family, mt_name, rev);
 667         if (IS_ERR(match))
 668                 return ERR_PTR(-ENOENT);
 669
 670         if (match->matchsize > nla_len(tb[NFTA_MATCH_INFO])) {
 671                 err = -EINVAL;
 672                 goto err;
 673         }
 674
 675         /* This is the first time we use this match, allocate operations */
 676         nft_match = kzalloc(sizeof(struct nft_xt), GFP_KERNEL);
 677         if (nft_match == NULL) {
 678                 err = -ENOMEM;
 679                 goto err;
 680         }
 681
 682         nft_match->refcnt = 1;
 683         nft_match->ops.type = &nft_match_type;
 684         nft_match->ops.size = NFT_EXPR_SIZE(XT_ALIGN(match->matchsize));
 685         nft_match->ops.eval = nft_match_eval;
 686         nft_match->ops.init = nft_match_init;
 687         nft_match->ops.destroy = nft_match_destroy;
 688         nft_match->ops.dump = nft_match_dump;
 689         nft_match->ops.validate = nft_match_validate;
 690         nft_match->ops.data = match;
 691
 692         list_add(&nft_match->head, &nft_match_list);
 693
 694         return &nft_match->ops;
 695 err:
 696         module_put(match->me);
 697         return ERR_PTR(err);
 698 }
 699
 700 static struct nft_expr_type nft_match_type __read_mostly = {
 701         .name           = "match",
 702         .select_ops     = nft_match_select_ops,
 703         .policy         = nft_match_policy,
 704         .maxattr        = NFTA_MATCH_MAX,
 705         .owner          = THIS_MODULE,
 706 };
 707
 708 static LIST_HEAD(nft_target_list);
 709
 710 static struct nft_expr_type nft_target_type;
 711
 712 static bool nft_target_cmp(const struct xt_target *tg,
 713                            const char *name, u32 rev, u32 family)
 714 {
 715         return strcmp(tg->name, name) == 0 && tg->revision == rev &&
 716                (tg->family == NFPROTO_UNSPEC || tg->family == family);
 717 }
 718
 719 static const struct nft_expr_ops *
 720 nft_target_select_ops(const struct nft_ctx *ctx,
 721                       const struct nlattr * const tb[])
 722 {
 723         struct nft_xt *nft_target;
 724         struct xt_target *target;
 725         char *tg_name;
 726         u32 rev, family;
 727         int err;
 728
 729         if (tb[NFTA_TARGET_NAME] == NULL ||
 730             tb[NFTA_TARGET_REV] == NULL ||
 731             tb[NFTA_TARGET_INFO] == NULL)
 732                 return ERR_PTR(-EINVAL);
 733
 734         tg_name = nla_data(tb[NFTA_TARGET_NAME]);
 735         rev = ntohl(nla_get_be32(tb[NFTA_TARGET_REV]));
 736         family = ctx->afi->family;
 737
 738         /* Re-use the existing target if it's already loaded. */
 739         list_for_each_entry(nft_target, &nft_target_list, head) {
 740                 struct xt_target *target = nft_target->ops.data;
 741
 742                 if (nft_target_cmp(target, tg_name, rev, family)) {
 743                         if (!try_module_get(target->me))
 744                                 return ERR_PTR(-ENOENT);
 745
 746                         nft_target->refcnt++;
 747                         return &nft_target->ops;
 748                 }
 749         }
 750
 751         target = xt_request_find_target(family, tg_name, rev);
 752         if (IS_ERR(target))
 753                 return ERR_PTR(-ENOENT);
 754
 755         if (target->targetsize > nla_len(tb[NFTA_TARGET_INFO])) {
 756                 err = -EINVAL;
 757                 goto err;
 758         }
 759
 760         /* This is the first time we use this target, allocate operations */
 761         nft_target = kzalloc(sizeof(struct nft_xt), GFP_KERNEL);
 762         if (nft_target == NULL) {
 763                 err = -ENOMEM;
 764                 goto err;
 765         }
 766
 767         nft_target->refcnt = 1;
 768         nft_target->ops.type = &nft_target_type;
 769         nft_target->ops.size = NFT_EXPR_SIZE(XT_ALIGN(target->targetsize));
 770         nft_target->ops.init = nft_target_init;
 771         nft_target->ops.destroy = nft_target_destroy;
 772         nft_target->ops.dump = nft_target_dump;
 773         nft_target->ops.validate = nft_target_validate;
 774         nft_target->ops.data = target;
 775
 776         if (family == NFPROTO_BRIDGE)
 777                 nft_target->ops.eval = nft_target_eval_bridge;
 778         else
 779                 nft_target->ops.eval = nft_target_eval_xt;
 780
 781         list_add(&nft_target->head, &nft_target_list);
 782
 783         return &nft_target->ops;
 784 err:
 785         module_put(target->me);
 786         return ERR_PTR(err);
 787 }
 788
 789 static struct nft_expr_type nft_target_type __read_mostly = {
 790         .name           = "target",
 791         .select_ops     = nft_target_select_ops,
 792         .policy         = nft_target_policy,
 793         .maxattr        = NFTA_TARGET_MAX,
 794         .owner          = THIS_MODULE,
 795 };
 796
 797 static int __init nft_compat_module_init(void)
 798 {
 799         int ret;
 800
 801         ret = nft_register_expr(&nft_match_type);
 802         if (ret < 0)
 803                 return ret;
 804
 805         ret = nft_register_expr(&nft_target_type);
 806         if (ret < 0)
 807                 goto err_match;
 808
 809         ret = nfnetlink_subsys_register(&nfnl_compat_subsys);
 810         if (ret < 0) {
 811                 pr_err("nft_compat: cannot register with nfnetlink.\n");
 812                 goto err_target;
 813         }
 814
 815         pr_info("nf_tables_compat: (c) 2012 Pablo Neira Ayuso <pablo@netfilter.org>\n");
 816
 817         return ret;
 818
 819 err_target:
 820         nft_unregister_expr(&nft_target_type);
 821 err_match:
 822         nft_unregister_expr(&nft_match_type);
 823         return ret;
 824 }
 825
 826 static void __exit nft_compat_module_exit(void)
 827 {
 828         nfnetlink_subsys_unregister(&nfnl_compat_subsys);
 829         nft_unregister_expr(&nft_target_type);
 830         nft_unregister_expr(&nft_match_type);
 831 }
 832
 833 MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_NFT_COMPAT);
 834
 835 module_init(nft_compat_module_init);
 836 module_exit(nft_compat_module_exit);
 837
 838 MODULE_LICENSE("GPL");
 839 MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
 840 MODULE_ALIAS_NFT_EXPR("match");
 841 MODULE_ALIAS_NFT_EXPR("target");