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 || !(chain->flags & NFT_BASE_CHAIN))
  46                 return 0;
  47
  48         basechain = nft_base_chain(chain);
  49         if (strcmp(tablename, "nat") == 0 &&
  50             basechain->type->type != NFT_CHAIN_T_NAT)
  51                 return -EINVAL;
  52
  53         return 0;
  54 }
  55
  56 union nft_entry {
  57         struct ipt_entry e4;
  58         struct ip6t_entry e6;
  59         struct ebt_entry ebt;
  60         struct arpt_entry arp;
  61 };
  62
  63 static inline void
  64 nft_compat_set_par(struct xt_action_param *par, void *xt, const void *xt_info)
  65 {
  66         par->target     = xt;
  67         par->targinfo   = xt_info;
  68         par->hotdrop    = false;
  69 }
  70
  71 static void nft_target_eval_xt(const struct nft_expr *expr,
  72                                struct nft_regs *regs,
  73                                const struct nft_pktinfo *pkt)
  74 {
  75         void *info = nft_expr_priv(expr);
  76         struct xt_target *target = expr->ops->data;
  77         struct sk_buff *skb = pkt->skb;
  78         int ret;
  79
  80         nft_compat_set_par((struct xt_action_param *)&pkt->xt, target, info);
  81
  82         ret = target->target(skb, &pkt->xt);
  83
  84         if (pkt->xt.hotdrop)
  85                 ret = NF_DROP;
  86
  87         switch (ret) {
  88         case XT_CONTINUE:
  89                 regs->verdict.code = NFT_CONTINUE;
  90                 break;
  91         default:
  92                 regs->verdict.code = ret;
  93                 break;
  94         }
  95 }
  96
  97 static void nft_target_eval_bridge(const struct nft_expr *expr,
  98                                    struct nft_regs *regs,
  99                                    const struct nft_pktinfo *pkt)
 100 {
 101         void *info = nft_expr_priv(expr);
 102         struct xt_target *target = expr->ops->data;
 103         struct sk_buff *skb = pkt->skb;
 104         int ret;
 105
 106         nft_compat_set_par((struct xt_action_param *)&pkt->xt, target, info);
 107
 108         ret = target->target(skb, &pkt->xt);
 109
 110         if (pkt->xt.hotdrop)
 111                 ret = NF_DROP;
 112
 113         switch (ret) {
 114         case EBT_ACCEPT:
 115                 regs->verdict.code = NF_ACCEPT;
 116                 break;
 117         case EBT_DROP:
 118                 regs->verdict.code = NF_DROP;
 119                 break;
 120         case EBT_CONTINUE:
 121                 regs->verdict.code = NFT_CONTINUE;
 122                 break;
 123         case EBT_RETURN:
 124                 regs->verdict.code = NFT_RETURN;
 125                 break;
 126         default:
 127                 regs->verdict.code = ret;
 128                 break;
 129         }
 130 }
 131
 132 static const struct nla_policy nft_target_policy[NFTA_TARGET_MAX + 1] = {
 133         [NFTA_TARGET_NAME]      = { .type = NLA_NUL_STRING },
 134         [NFTA_TARGET_REV]       = { .type = NLA_U32 },
 135         [NFTA_TARGET_INFO]      = { .type = NLA_BINARY },
 136 };
 137
 138 static void
 139 nft_target_set_tgchk_param(struct xt_tgchk_param *par,
 140                            const struct nft_ctx *ctx,
 141                            struct xt_target *target, void *info,
 142                            union nft_entry *entry, u16 proto, bool inv)
 143 {
 144         par->net        = ctx->net;
 145         par->table      = ctx->table->name;
 146         switch (ctx->afi->family) {
 147         case AF_INET:
 148                 entry->e4.ip.proto = proto;
 149                 entry->e4.ip.invflags = inv ? IPT_INV_PROTO : 0;
 150                 break;
 151         case AF_INET6:
 152                 if (proto)
 153                         entry->e6.ipv6.flags |= IP6T_F_PROTO;
 154
 155                 entry->e6.ipv6.proto = proto;
 156                 entry->e6.ipv6.invflags = inv ? IP6T_INV_PROTO : 0;
 157                 break;
 158         case NFPROTO_BRIDGE:
 159                 entry->ebt.ethproto = (__force __be16)proto;
 160                 entry->ebt.invflags = inv ? EBT_IPROTO : 0;
 161                 break;
 162         case NFPROTO_ARP:
 163                 break;
 164         }
 165         par->entryinfo  = entry;
 166         par->target     = target;
 167         par->targinfo   = info;
 168         if (ctx->chain->flags & NFT_BASE_CHAIN) {
 169                 const struct nft_base_chain *basechain =
 170                                                 nft_base_chain(ctx->chain);
 171                 const struct nf_hook_ops *ops = &basechain->ops[0];
 172
 173                 par->hook_mask = 1 << ops->hooknum;
 174         } else {
 175                 par->hook_mask = 0;
 176         }
 177         par->family     = ctx->afi->family;
 178         par->nft_compat = true;
 179 }
 180
 181 static void target_compat_from_user(struct xt_target *t, void *in, void *out)
 182 {
 183         int pad;
 184
 185         memcpy(out, in, t->targetsize);
 186         pad = XT_ALIGN(t->targetsize) - t->targetsize;
 187         if (pad > 0)
 188                 memset(out + t->targetsize, 0, pad);
 189 }
 190
 191 static const struct nla_policy nft_rule_compat_policy[NFTA_RULE_COMPAT_MAX + 1] = {
 192         [NFTA_RULE_COMPAT_PROTO]        = { .type = NLA_U32 },
 193         [NFTA_RULE_COMPAT_FLAGS]        = { .type = NLA_U32 },
 194 };
 195
 196 static int nft_parse_compat(const struct nlattr *attr, u16 *proto, bool *inv)
 197 {
 198         struct nlattr *tb[NFTA_RULE_COMPAT_MAX+1];
 199         u32 flags;
 200         int err;
 201
 202         err = nla_parse_nested(tb, NFTA_RULE_COMPAT_MAX, attr,
 203                                nft_rule_compat_policy, NULL);
 204         if (err < 0)
 205                 return err;
 206
 207         if (!tb[NFTA_RULE_COMPAT_PROTO] || !tb[NFTA_RULE_COMPAT_FLAGS])
 208                 return -EINVAL;
 209
 210         flags = ntohl(nla_get_be32(tb[NFTA_RULE_COMPAT_FLAGS]));
 211         if (flags & ~NFT_RULE_COMPAT_F_MASK)
 212                 return -EINVAL;
 213         if (flags & NFT_RULE_COMPAT_F_INV)
 214                 *inv = true;
 215
 216         *proto = ntohl(nla_get_be32(tb[NFTA_RULE_COMPAT_PROTO]));
 217         return 0;
 218 }
 219
 220 static int
 221 nft_target_init(const struct nft_ctx *ctx, const struct nft_expr *expr,
 222                 const struct nlattr * const tb[])
 223 {
 224         void *info = nft_expr_priv(expr);
 225         struct xt_target *target = expr->ops->data;
 226         struct xt_tgchk_param par;
 227         size_t size = XT_ALIGN(nla_len(tb[NFTA_TARGET_INFO]));
 228         u16 proto = 0;
 229         bool inv = false;
 230         union nft_entry e = {};
 231         int ret;
 232
 233         target_compat_from_user(target, nla_data(tb[NFTA_TARGET_INFO]), info);
 234
 235         if (ctx->nla[NFTA_RULE_COMPAT]) {
 236                 ret = nft_parse_compat(ctx->nla[NFTA_RULE_COMPAT], &proto, &inv);
 237                 if (ret < 0)
 238                         goto err;
 239         }
 240
 241         nft_target_set_tgchk_param(&par, ctx, target, info, &e, proto, inv);
 242
 243         ret = xt_check_target(&par, size, proto, inv);
 244         if (ret < 0)
 245                 goto err;
 246
 247         /* The standard target cannot be used */
 248         if (target->target == NULL) {
 249                 ret = -EINVAL;
 250                 goto err;
 251         }
 252
 253         return 0;
 254 err:
 255         module_put(target->me);
 256         return ret;
 257 }
 258
 259 static void
 260 nft_target_destroy(const struct nft_ctx *ctx, const struct nft_expr *expr)
 261 {
 262         struct xt_target *target = expr->ops->data;
 263         void *info = nft_expr_priv(expr);
 264         struct xt_tgdtor_param par;
 265
 266         par.net = ctx->net;
 267         par.target = target;
 268         par.targinfo = info;
 269         par.family = ctx->afi->family;
 270         if (par.target->destroy != NULL)
 271                 par.target->destroy(&par);
 272
 273         nft_xt_put(container_of(expr->ops, struct nft_xt, ops));
 274         module_put(target->me);
 275 }
 276
 277 static int nft_target_dump(struct sk_buff *skb, const struct nft_expr *expr)
 278 {
 279         const struct xt_target *target = expr->ops->data;
 280         void *info = nft_expr_priv(expr);
 281
 282         if (nla_put_string(skb, NFTA_TARGET_NAME, target->name) ||
 283             nla_put_be32(skb, NFTA_TARGET_REV, htonl(target->revision)) ||
 284             nla_put(skb, NFTA_TARGET_INFO, XT_ALIGN(target->targetsize), info))
 285                 goto nla_put_failure;
 286
 287         return 0;
 288
 289 nla_put_failure:
 290         return -1;
 291 }
 292
 293 static int nft_target_validate(const struct nft_ctx *ctx,
 294                                const struct nft_expr *expr,
 295                                const struct nft_data **data)
 296 {
 297         struct xt_target *target = expr->ops->data;
 298         unsigned int hook_mask = 0;
 299         int ret;
 300
 301         if (ctx->chain->flags & NFT_BASE_CHAIN) {
 302                 const struct nft_base_chain *basechain =
 303                                                 nft_base_chain(ctx->chain);
 304                 const struct nf_hook_ops *ops = &basechain->ops[0];
 305
 306                 hook_mask = 1 << ops->hooknum;
 307                 if (!(hook_mask & target->hooks))
 308                         return -EINVAL;
 309
 310                 ret = nft_compat_chain_validate_dependency(target->table,
 311                                                            ctx->chain);
 312                 if (ret < 0)
 313                         return ret;
 314         }
 315         return 0;
 316 }
 317
 318 static void nft_match_eval(const struct nft_expr *expr,
 319                            struct nft_regs *regs,
 320                            const struct nft_pktinfo *pkt)
 321 {
 322         void *info = nft_expr_priv(expr);
 323         struct xt_match *match = expr->ops->data;
 324         struct sk_buff *skb = pkt->skb;
 325         bool ret;
 326
 327         nft_compat_set_par((struct xt_action_param *)&pkt->xt, match, info);
 328
 329         ret = match->match(skb, (struct xt_action_param *)&pkt->xt);
 330
 331         if (pkt->xt.hotdrop) {
 332                 regs->verdict.code = NF_DROP;
 333                 return;
 334         }
 335
 336         switch (ret ? 1 : 0) {
 337         case 1:
 338                 regs->verdict.code = NFT_CONTINUE;
 339                 break;
 340         case 0:
 341                 regs->verdict.code = NFT_BREAK;
 342                 break;
 343         }
 344 }
 345
 346 static const struct nla_policy nft_match_policy[NFTA_MATCH_MAX + 1] = {
 347         [NFTA_MATCH_NAME]       = { .type = NLA_NUL_STRING },
 348         [NFTA_MATCH_REV]        = { .type = NLA_U32 },
 349         [NFTA_MATCH_INFO]       = { .type = NLA_BINARY },
 350 };
 351
 352 /* struct xt_mtchk_param and xt_tgchk_param look very similar */
 353 static void
 354 nft_match_set_mtchk_param(struct xt_mtchk_param *par, const struct nft_ctx *ctx,
 355                           struct xt_match *match, void *info,
 356                           union nft_entry *entry, u16 proto, bool inv)
 357 {
 358         par->net        = ctx->net;
 359         par->table      = ctx->table->name;
 360         switch (ctx->afi->family) {
 361         case AF_INET:
 362                 entry->e4.ip.proto = proto;
 363                 entry->e4.ip.invflags = inv ? IPT_INV_PROTO : 0;
 364                 break;
 365         case AF_INET6:
 366                 if (proto)
 367                         entry->e6.ipv6.flags |= IP6T_F_PROTO;
 368
 369                 entry->e6.ipv6.proto = proto;
 370                 entry->e6.ipv6.invflags = inv ? IP6T_INV_PROTO : 0;
 371                 break;
 372         case NFPROTO_BRIDGE:
 373                 entry->ebt.ethproto = (__force __be16)proto;
 374                 entry->ebt.invflags = inv ? EBT_IPROTO : 0;
 375                 break;
 376         case NFPROTO_ARP:
 377                 break;
 378         }
 379         par->entryinfo  = entry;
 380         par->match      = match;
 381         par->matchinfo  = info;
 382         if (ctx->chain->flags & NFT_BASE_CHAIN) {
 383                 const struct nft_base_chain *basechain =
 384                                                 nft_base_chain(ctx->chain);
 385                 const struct nf_hook_ops *ops = &basechain->ops[0];
 386
 387                 par->hook_mask = 1 << ops->hooknum;
 388         } else {
 389                 par->hook_mask = 0;
 390         }
 391         par->family     = ctx->afi->family;
 392         par->nft_compat = true;
 393 }
 394
 395 static void match_compat_from_user(struct xt_match *m, void *in, void *out)
 396 {
 397         int pad;
 398
 399         memcpy(out, in, m->matchsize);
 400         pad = XT_ALIGN(m->matchsize) - m->matchsize;
 401         if (pad > 0)
 402                 memset(out + m->matchsize, 0, pad);
 403 }
 404
 405 static int
 406 nft_match_init(const struct nft_ctx *ctx, const struct nft_expr *expr,
 407                 const struct nlattr * const tb[])
 408 {
 409         void *info = nft_expr_priv(expr);
 410         struct xt_match *match = expr->ops->data;
 411         struct xt_mtchk_param par;
 412         size_t size = XT_ALIGN(nla_len(tb[NFTA_MATCH_INFO]));
 413         u16 proto = 0;
 414         bool inv = false;
 415         union nft_entry e = {};
 416         int ret;
 417
 418         match_compat_from_user(match, nla_data(tb[NFTA_MATCH_INFO]), info);
 419
 420         if (ctx->nla[NFTA_RULE_COMPAT]) {
 421                 ret = nft_parse_compat(ctx->nla[NFTA_RULE_COMPAT], &proto, &inv);
 422                 if (ret < 0)
 423                         goto err;
 424         }
 425
 426         nft_match_set_mtchk_param(&par, ctx, match, info, &e, proto, inv);
 427
 428         ret = xt_check_match(&par, size, proto, inv);
 429         if (ret < 0)
 430                 goto err;
 431
 432         return 0;
 433 err:
 434         module_put(match->me);
 435         return ret;
 436 }
 437
 438 static void
 439 nft_match_destroy(const struct nft_ctx *ctx, const struct nft_expr *expr)
 440 {
 441         struct xt_match *match = expr->ops->data;
 442         void *info = nft_expr_priv(expr);
 443         struct xt_mtdtor_param par;
 444
 445         par.net = ctx->net;
 446         par.match = match;
 447         par.matchinfo = info;
 448         par.family = ctx->afi->family;
 449         if (par.match->destroy != NULL)
 450                 par.match->destroy(&par);
 451
 452         nft_xt_put(container_of(expr->ops, struct nft_xt, ops));
 453         module_put(match->me);
 454 }
 455
 456 static int nft_match_dump(struct sk_buff *skb, const struct nft_expr *expr)
 457 {
 458         void *info = nft_expr_priv(expr);
 459         struct xt_match *match = expr->ops->data;
 460
 461         if (nla_put_string(skb, NFTA_MATCH_NAME, match->name) ||
 462             nla_put_be32(skb, NFTA_MATCH_REV, htonl(match->revision)) ||
 463             nla_put(skb, NFTA_MATCH_INFO, XT_ALIGN(match->matchsize), info))
 464                 goto nla_put_failure;
 465
 466         return 0;
 467
 468 nla_put_failure:
 469         return -1;
 470 }
 471
 472 static int nft_match_validate(const struct nft_ctx *ctx,
 473                               const struct nft_expr *expr,
 474                               const struct nft_data **data)
 475 {
 476         struct xt_match *match = expr->ops->data;
 477         unsigned int hook_mask = 0;
 478         int ret;
 479
 480         if (ctx->chain->flags & NFT_BASE_CHAIN) {
 481                 const struct nft_base_chain *basechain =
 482                                                 nft_base_chain(ctx->chain);
 483                 const struct nf_hook_ops *ops = &basechain->ops[0];
 484
 485                 hook_mask = 1 << ops->hooknum;
 486                 if (!(hook_mask & match->hooks))
 487                         return -EINVAL;
 488
 489                 ret = nft_compat_chain_validate_dependency(match->table,
 490                                                            ctx->chain);
 491                 if (ret < 0)
 492                         return ret;
 493         }
 494         return 0;
 495 }
 496
 497 static int
 498 nfnl_compat_fill_info(struct sk_buff *skb, u32 portid, u32 seq, u32 type,
 499                       int event, u16 family, const char *name,
 500                       int rev, int target)
 501 {
 502         struct nlmsghdr *nlh;
 503         struct nfgenmsg *nfmsg;
 504         unsigned int flags = portid ? NLM_F_MULTI : 0;
 505
 506         event |= NFNL_SUBSYS_NFT_COMPAT << 8;
 507         nlh = nlmsg_put(skb, portid, seq, event, sizeof(*nfmsg), flags);
 508         if (nlh == NULL)
 509                 goto nlmsg_failure;
 510
 511         nfmsg = nlmsg_data(nlh);
 512         nfmsg->nfgen_family = family;
 513         nfmsg->version = NFNETLINK_V0;
 514         nfmsg->res_id = 0;
 515
 516         if (nla_put_string(skb, NFTA_COMPAT_NAME, name) ||
 517             nla_put_be32(skb, NFTA_COMPAT_REV, htonl(rev)) ||
 518             nla_put_be32(skb, NFTA_COMPAT_TYPE, htonl(target)))
 519                 goto nla_put_failure;
 520
 521         nlmsg_end(skb, nlh);
 522         return skb->len;
 523
 524 nlmsg_failure:
 525 nla_put_failure:
 526         nlmsg_cancel(skb, nlh);
 527         return -1;
 528 }
 529
 530 static int nfnl_compat_get(struct net *net, struct sock *nfnl,
 531                            struct sk_buff *skb, const struct nlmsghdr *nlh,
 532                            const struct nlattr * const tb[])
 533 {
 534         int ret = 0, target;
 535         struct nfgenmsg *nfmsg;
 536         const char *fmt;
 537         const char *name;
 538         u32 rev;
 539         struct sk_buff *skb2;
 540
 541         if (tb[NFTA_COMPAT_NAME] == NULL ||
 542             tb[NFTA_COMPAT_REV] == NULL ||
 543             tb[NFTA_COMPAT_TYPE] == NULL)
 544                 return -EINVAL;
 545
 546         name = nla_data(tb[NFTA_COMPAT_NAME]);
 547         rev = ntohl(nla_get_be32(tb[NFTA_COMPAT_REV]));
 548         target = ntohl(nla_get_be32(tb[NFTA_COMPAT_TYPE]));
 549
 550         nfmsg = nlmsg_data(nlh);
 551
 552         switch(nfmsg->nfgen_family) {
 553         case AF_INET:
 554                 fmt = "ipt_%s";
 555                 break;
 556         case AF_INET6:
 557                 fmt = "ip6t_%s";
 558                 break;
 559         case NFPROTO_BRIDGE:
 560                 fmt = "ebt_%s";
 561                 break;
 562         case NFPROTO_ARP:
 563                 fmt = "arpt_%s";
 564                 break;
 565         default:
 566                 pr_err("nft_compat: unsupported protocol %d\n",
 567                         nfmsg->nfgen_family);
 568                 return -EINVAL;
 569         }
 570
 571         try_then_request_module(xt_find_revision(nfmsg->nfgen_family, name,
 572                                                  rev, target, &ret),
 573                                                  fmt, name);
 574
 575         if (ret < 0)
 576                 return ret;
 577
 578         skb2 = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 579         if (skb2 == NULL)
 580                 return -ENOMEM;
 581
 582         /* include the best revision for this extension in the message */
 583         if (nfnl_compat_fill_info(skb2, NETLINK_CB(skb).portid,
 584                                   nlh->nlmsg_seq,
 585                                   NFNL_MSG_TYPE(nlh->nlmsg_type),
 586                                   NFNL_MSG_COMPAT_GET,
 587                                   nfmsg->nfgen_family,
 588                                   name, ret, target) <= 0) {
 589                 kfree_skb(skb2);
 590                 return -ENOSPC;
 591         }
 592
 593         ret = netlink_unicast(nfnl, skb2, NETLINK_CB(skb).portid,
 594                                 MSG_DONTWAIT);
 595         if (ret > 0)
 596                 ret = 0;
 597
 598         return ret == -EAGAIN ? -ENOBUFS : ret;
 599 }
 600
 601 static const struct nla_policy nfnl_compat_policy_get[NFTA_COMPAT_MAX+1] = {
 602         [NFTA_COMPAT_NAME]      = { .type = NLA_NUL_STRING,
 603                                     .len = NFT_COMPAT_NAME_MAX-1 },
 604         [NFTA_COMPAT_REV]       = { .type = NLA_U32 },
 605         [NFTA_COMPAT_TYPE]      = { .type = NLA_U32 },
 606 };
 607
 608 static const struct nfnl_callback nfnl_nft_compat_cb[NFNL_MSG_COMPAT_MAX] = {
 609         [NFNL_MSG_COMPAT_GET]           = { .call = nfnl_compat_get,
 610                                             .attr_count = NFTA_COMPAT_MAX,
 611                                             .policy = nfnl_compat_policy_get },
 612 };
 613
 614 static const struct nfnetlink_subsystem nfnl_compat_subsys = {
 615         .name           = "nft-compat",
 616         .subsys_id      = NFNL_SUBSYS_NFT_COMPAT,
 617         .cb_count       = NFNL_MSG_COMPAT_MAX,
 618         .cb             = nfnl_nft_compat_cb,
 619 };
 620
 621 static LIST_HEAD(nft_match_list);
 622
 623 static struct nft_expr_type nft_match_type;
 624
 625 static bool nft_match_cmp(const struct xt_match *match,
 626                           const char *name, u32 rev, u32 family)
 627 {
 628         return strcmp(match->name, name) == 0 && match->revision == rev &&
 629                (match->family == NFPROTO_UNSPEC || match->family == family);
 630 }
 631
 632 static const struct nft_expr_ops *
 633 nft_match_select_ops(const struct nft_ctx *ctx,
 634                      const struct nlattr * const tb[])
 635 {
 636         struct nft_xt *nft_match;
 637         struct xt_match *match;
 638         char *mt_name;
 639         u32 rev, family;
 640         int err;
 641
 642         if (tb[NFTA_MATCH_NAME] == NULL ||
 643             tb[NFTA_MATCH_REV] == NULL ||
 644             tb[NFTA_MATCH_INFO] == NULL)
 645                 return ERR_PTR(-EINVAL);
 646
 647         mt_name = nla_data(tb[NFTA_MATCH_NAME]);
 648         rev = ntohl(nla_get_be32(tb[NFTA_MATCH_REV]));
 649         family = ctx->afi->family;
 650
 651         /* Re-use the existing match if it's already loaded. */
 652         list_for_each_entry(nft_match, &nft_match_list, head) {
 653                 struct xt_match *match = nft_match->ops.data;
 654
 655                 if (nft_match_cmp(match, mt_name, rev, family)) {
 656                         if (!try_module_get(match->me))
 657                                 return ERR_PTR(-ENOENT);
 658
 659                         nft_match->refcnt++;
 660                         return &nft_match->ops;
 661                 }
 662         }
 663
 664         match = xt_request_find_match(family, mt_name, rev);
 665         if (IS_ERR(match))
 666                 return ERR_PTR(-ENOENT);
 667
 668         if (match->matchsize > nla_len(tb[NFTA_MATCH_INFO])) {
 669                 err = -EINVAL;
 670                 goto err;
 671         }
 672
 673         /* This is the first time we use this match, allocate operations */
 674         nft_match = kzalloc(sizeof(struct nft_xt), GFP_KERNEL);
 675         if (nft_match == NULL) {
 676                 err = -ENOMEM;
 677                 goto err;
 678         }
 679
 680         nft_match->refcnt = 1;
 681         nft_match->ops.type = &nft_match_type;
 682         nft_match->ops.size = NFT_EXPR_SIZE(XT_ALIGN(match->matchsize));
 683         nft_match->ops.eval = nft_match_eval;
 684         nft_match->ops.init = nft_match_init;
 685         nft_match->ops.destroy = nft_match_destroy;
 686         nft_match->ops.dump = nft_match_dump;
 687         nft_match->ops.validate = nft_match_validate;
 688         nft_match->ops.data = match;
 689
 690         list_add(&nft_match->head, &nft_match_list);
 691
 692         return &nft_match->ops;
 693 err:
 694         module_put(match->me);
 695         return ERR_PTR(err);
 696 }
 697
 698 static struct nft_expr_type nft_match_type __read_mostly = {
 699         .name           = "match",
 700         .select_ops     = nft_match_select_ops,
 701         .policy         = nft_match_policy,
 702         .maxattr        = NFTA_MATCH_MAX,
 703         .owner          = THIS_MODULE,
 704 };
 705
 706 static LIST_HEAD(nft_target_list);
 707
 708 static struct nft_expr_type nft_target_type;
 709
 710 static bool nft_target_cmp(const struct xt_target *tg,
 711                            const char *name, u32 rev, u32 family)
 712 {
 713         return strcmp(tg->name, name) == 0 && tg->revision == rev &&
 714                (tg->family == NFPROTO_UNSPEC || tg->family == family);
 715 }
 716
 717 static const struct nft_expr_ops *
 718 nft_target_select_ops(const struct nft_ctx *ctx,
 719                       const struct nlattr * const tb[])
 720 {
 721         struct nft_xt *nft_target;
 722         struct xt_target *target;
 723         char *tg_name;
 724         u32 rev, family;
 725         int err;
 726
 727         if (tb[NFTA_TARGET_NAME] == NULL ||
 728             tb[NFTA_TARGET_REV] == NULL ||
 729             tb[NFTA_TARGET_INFO] == NULL)
 730                 return ERR_PTR(-EINVAL);
 731
 732         tg_name = nla_data(tb[NFTA_TARGET_NAME]);
 733         rev = ntohl(nla_get_be32(tb[NFTA_TARGET_REV]));
 734         family = ctx->afi->family;
 735
 736         /* Re-use the existing target if it's already loaded. */
 737         list_for_each_entry(nft_target, &nft_target_list, head) {
 738                 struct xt_target *target = nft_target->ops.data;
 739
 740                 if (nft_target_cmp(target, tg_name, rev, family)) {
 741                         if (!try_module_get(target->me))
 742                                 return ERR_PTR(-ENOENT);
 743
 744                         nft_target->refcnt++;
 745                         return &nft_target->ops;
 746                 }
 747         }
 748
 749         target = xt_request_find_target(family, tg_name, rev);
 750         if (IS_ERR(target))
 751                 return ERR_PTR(-ENOENT);
 752
 753         if (target->targetsize > nla_len(tb[NFTA_TARGET_INFO])) {
 754                 err = -EINVAL;
 755                 goto err;
 756         }
 757
 758         /* This is the first time we use this target, allocate operations */
 759         nft_target = kzalloc(sizeof(struct nft_xt), GFP_KERNEL);
 760         if (nft_target == NULL) {
 761                 err = -ENOMEM;
 762                 goto err;
 763         }
 764
 765         nft_target->refcnt = 1;
 766         nft_target->ops.type = &nft_target_type;
 767         nft_target->ops.size = NFT_EXPR_SIZE(XT_ALIGN(target->targetsize));
 768         nft_target->ops.init = nft_target_init;
 769         nft_target->ops.destroy = nft_target_destroy;
 770         nft_target->ops.dump = nft_target_dump;
 771         nft_target->ops.validate = nft_target_validate;
 772         nft_target->ops.data = target;
 773
 774         if (family == NFPROTO_BRIDGE)
 775                 nft_target->ops.eval = nft_target_eval_bridge;
 776         else
 777                 nft_target->ops.eval = nft_target_eval_xt;
 778
 779         list_add(&nft_target->head, &nft_target_list);
 780
 781         return &nft_target->ops;
 782 err:
 783         module_put(target->me);
 784         return ERR_PTR(err);
 785 }
 786
 787 static struct nft_expr_type nft_target_type __read_mostly = {
 788         .name           = "target",
 789         .select_ops     = nft_target_select_ops,
 790         .policy         = nft_target_policy,
 791         .maxattr        = NFTA_TARGET_MAX,
 792         .owner          = THIS_MODULE,
 793 };
 794
 795 static int __init nft_compat_module_init(void)
 796 {
 797         int ret;
 798
 799         ret = nft_register_expr(&nft_match_type);
 800         if (ret < 0)
 801                 return ret;
 802
 803         ret = nft_register_expr(&nft_target_type);
 804         if (ret < 0)
 805                 goto err_match;
 806
 807         ret = nfnetlink_subsys_register(&nfnl_compat_subsys);
 808         if (ret < 0) {
 809                 pr_err("nft_compat: cannot register with nfnetlink.\n");
 810                 goto err_target;
 811         }
 812
 813         pr_info("nf_tables_compat: (c) 2012 Pablo Neira Ayuso <pablo@netfilter.org>\n");
 814
 815         return ret;
 816
 817 err_target:
 818         nft_unregister_expr(&nft_target_type);
 819 err_match:
 820         nft_unregister_expr(&nft_match_type);
 821         return ret;
 822 }
 823
 824 static void __exit nft_compat_module_exit(void)
 825 {
 826         nfnetlink_subsys_unregister(&nfnl_compat_subsys);
 827         nft_unregister_expr(&nft_target_type);
 828         nft_unregister_expr(&nft_match_type);
 829 }
 830
 831 MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_NFT_COMPAT);
 832
 833 module_init(nft_compat_module_init);
 834 module_exit(nft_compat_module_exit);
 835
 836 MODULE_LICENSE("GPL");
 837 MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
 838 MODULE_ALIAS_NFT_EXPR("match");
 839 MODULE_ALIAS_NFT_EXPR("target");