linux/net/netfilter/nft_compat.c
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   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * (C) 2012-2013 by Pablo Neira Ayuso <pablo@netfilter.org>
   4 *
   5 * This software has been sponsored by Sophos Astaro <http://www.sophos.com>
   6 */
   7
   8#include <linux/kernel.h>
   9#include <linux/init.h>
  10#include <linux/module.h>
  11#include <linux/netlink.h>
  12#include <linux/netfilter.h>
  13#include <linux/netfilter/nfnetlink.h>
  14#include <linux/netfilter/nf_tables.h>
  15#include <linux/netfilter/nf_tables_compat.h>
  16#include <linux/netfilter/x_tables.h>
  17#include <linux/netfilter_ipv4/ip_tables.h>
  18#include <linux/netfilter_ipv6/ip6_tables.h>
  19#include <linux/netfilter_bridge/ebtables.h>
  20#include <linux/netfilter_arp/arp_tables.h>
  21#include <net/netfilter/nf_tables.h>
  22
  23/* Used for matches where *info is larger than X byte */
  24#define NFT_MATCH_LARGE_THRESH  192
  25
  26struct nft_xt_match_priv {
  27        void *info;
  28};
  29
  30static int nft_compat_chain_validate_dependency(const struct nft_ctx *ctx,
  31                                                const char *tablename)
  32{
  33        enum nft_chain_types type = NFT_CHAIN_T_DEFAULT;
  34        const struct nft_chain *chain = ctx->chain;
  35        const struct nft_base_chain *basechain;
  36
  37        if (!tablename ||
  38            !nft_is_base_chain(chain))
  39                return 0;
  40
  41        basechain = nft_base_chain(chain);
  42        if (strcmp(tablename, "nat") == 0) {
  43                if (ctx->family != NFPROTO_BRIDGE)
  44                        type = NFT_CHAIN_T_NAT;
  45                if (basechain->type->type != type)
  46                        return -EINVAL;
  47        }
  48
  49        return 0;
  50}
  51
  52union nft_entry {
  53        struct ipt_entry e4;
  54        struct ip6t_entry e6;
  55        struct ebt_entry ebt;
  56        struct arpt_entry arp;
  57};
  58
  59static inline void
  60nft_compat_set_par(struct xt_action_param *par, void *xt, const void *xt_info)
  61{
  62        par->target     = xt;
  63        par->targinfo   = xt_info;
  64        par->hotdrop    = false;
  65}
  66
  67static void nft_target_eval_xt(const struct nft_expr *expr,
  68                               struct nft_regs *regs,
  69                               const struct nft_pktinfo *pkt)
  70{
  71        void *info = nft_expr_priv(expr);
  72        struct xt_target *target = expr->ops->data;
  73        struct sk_buff *skb = pkt->skb;
  74        int ret;
  75
  76        nft_compat_set_par((struct xt_action_param *)&pkt->xt, target, info);
  77
  78        ret = target->target(skb, &pkt->xt);
  79
  80        if (pkt->xt.hotdrop)
  81                ret = NF_DROP;
  82
  83        switch (ret) {
  84        case XT_CONTINUE:
  85                regs->verdict.code = NFT_CONTINUE;
  86                break;
  87        default:
  88                regs->verdict.code = ret;
  89                break;
  90        }
  91}
  92
  93static void nft_target_eval_bridge(const struct nft_expr *expr,
  94                                   struct nft_regs *regs,
  95                                   const struct nft_pktinfo *pkt)
  96{
  97        void *info = nft_expr_priv(expr);
  98        struct xt_target *target = expr->ops->data;
  99        struct sk_buff *skb = pkt->skb;
 100        int ret;
 101
 102        nft_compat_set_par((struct xt_action_param *)&pkt->xt, target, info);
 103
 104        ret = target->target(skb, &pkt->xt);
 105
 106        if (pkt->xt.hotdrop)
 107                ret = NF_DROP;
 108
 109        switch (ret) {
 110        case EBT_ACCEPT:
 111                regs->verdict.code = NF_ACCEPT;
 112                break;
 113        case EBT_DROP:
 114                regs->verdict.code = NF_DROP;
 115                break;
 116        case EBT_CONTINUE:
 117                regs->verdict.code = NFT_CONTINUE;
 118                break;
 119        case EBT_RETURN:
 120                regs->verdict.code = NFT_RETURN;
 121                break;
 122        default:
 123                regs->verdict.code = ret;
 124                break;
 125        }
 126}
 127
 128static const struct nla_policy nft_target_policy[NFTA_TARGET_MAX + 1] = {
 129        [NFTA_TARGET_NAME]      = { .type = NLA_NUL_STRING },
 130        [NFTA_TARGET_REV]       = { .type = NLA_U32 },
 131        [NFTA_TARGET_INFO]      = { .type = NLA_BINARY },
 132};
 133
 134static void
 135nft_target_set_tgchk_param(struct xt_tgchk_param *par,
 136                           const struct nft_ctx *ctx,
 137                           struct xt_target *target, void *info,
 138                           union nft_entry *entry, u16 proto, bool inv)
 139{
 140        par->net        = ctx->net;
 141        par->table      = ctx->table->name;
 142        switch (ctx->family) {
 143        case AF_INET:
 144                entry->e4.ip.proto = proto;
 145                entry->e4.ip.invflags = inv ? IPT_INV_PROTO : 0;
 146                break;
 147        case AF_INET6:
 148                if (proto)
 149                        entry->e6.ipv6.flags |= IP6T_F_PROTO;
 150
 151                entry->e6.ipv6.proto = proto;
 152                entry->e6.ipv6.invflags = inv ? IP6T_INV_PROTO : 0;
 153                break;
 154        case NFPROTO_BRIDGE:
 155                entry->ebt.ethproto = (__force __be16)proto;
 156                entry->ebt.invflags = inv ? EBT_IPROTO : 0;
 157                break;
 158        case NFPROTO_ARP:
 159                break;
 160        }
 161        par->entryinfo  = entry;
 162        par->target     = target;
 163        par->targinfo   = info;
 164        if (nft_is_base_chain(ctx->chain)) {
 165                const struct nft_base_chain *basechain =
 166                                                nft_base_chain(ctx->chain);
 167                const struct nf_hook_ops *ops = &basechain->ops;
 168
 169                par->hook_mask = 1 << ops->hooknum;
 170        } else {
 171                par->hook_mask = 0;
 172        }
 173        par->family     = ctx->family;
 174        par->nft_compat = true;
 175}
 176
 177static void target_compat_from_user(struct xt_target *t, void *in, void *out)
 178{
 179        int pad;
 180
 181        memcpy(out, in, t->targetsize);
 182        pad = XT_ALIGN(t->targetsize) - t->targetsize;
 183        if (pad > 0)
 184                memset(out + t->targetsize, 0, pad);
 185}
 186
 187static const struct nla_policy nft_rule_compat_policy[NFTA_RULE_COMPAT_MAX + 1] = {
 188        [NFTA_RULE_COMPAT_PROTO]        = { .type = NLA_U32 },
 189        [NFTA_RULE_COMPAT_FLAGS]        = { .type = NLA_U32 },
 190};
 191
 192static int nft_parse_compat(const struct nlattr *attr, u16 *proto, bool *inv)
 193{
 194        struct nlattr *tb[NFTA_RULE_COMPAT_MAX+1];
 195        u32 flags;
 196        int err;
 197
 198        err = nla_parse_nested_deprecated(tb, NFTA_RULE_COMPAT_MAX, attr,
 199                                          nft_rule_compat_policy, NULL);
 200        if (err < 0)
 201                return err;
 202
 203        if (!tb[NFTA_RULE_COMPAT_PROTO] || !tb[NFTA_RULE_COMPAT_FLAGS])
 204                return -EINVAL;
 205
 206        flags = ntohl(nla_get_be32(tb[NFTA_RULE_COMPAT_FLAGS]));
 207        if (flags & ~NFT_RULE_COMPAT_F_MASK)
 208                return -EINVAL;
 209        if (flags & NFT_RULE_COMPAT_F_INV)
 210                *inv = true;
 211
 212        *proto = ntohl(nla_get_be32(tb[NFTA_RULE_COMPAT_PROTO]));
 213        return 0;
 214}
 215
 216static int
 217nft_target_init(const struct nft_ctx *ctx, const struct nft_expr *expr,
 218                const struct nlattr * const tb[])
 219{
 220        void *info = nft_expr_priv(expr);
 221        struct xt_target *target = expr->ops->data;
 222        struct xt_tgchk_param par;
 223        size_t size = XT_ALIGN(nla_len(tb[NFTA_TARGET_INFO]));
 224        u16 proto = 0;
 225        bool inv = false;
 226        union nft_entry e = {};
 227        int ret;
 228
 229        target_compat_from_user(target, nla_data(tb[NFTA_TARGET_INFO]), info);
 230
 231        if (ctx->nla[NFTA_RULE_COMPAT]) {
 232                ret = nft_parse_compat(ctx->nla[NFTA_RULE_COMPAT], &proto, &inv);
 233                if (ret < 0)
 234                        return ret;
 235        }
 236
 237        nft_target_set_tgchk_param(&par, ctx, target, info, &e, proto, inv);
 238
 239        ret = xt_check_target(&par, size, proto, inv);
 240        if (ret < 0)
 241                return ret;
 242
 243        /* The standard target cannot be used */
 244        if (!target->target)
 245                return -EINVAL;
 246
 247        return 0;
 248}
 249
 250static void
 251nft_target_destroy(const struct nft_ctx *ctx, const struct nft_expr *expr)
 252{
 253        struct xt_target *target = expr->ops->data;
 254        void *info = nft_expr_priv(expr);
 255        struct module *me = target->me;
 256        struct xt_tgdtor_param par;
 257
 258        par.net = ctx->net;
 259        par.target = target;
 260        par.targinfo = info;
 261        par.family = ctx->family;
 262        if (par.target->destroy != NULL)
 263                par.target->destroy(&par);
 264
 265        module_put(me);
 266        kfree(expr->ops);
 267}
 268
 269static int nft_extension_dump_info(struct sk_buff *skb, int attr,
 270                                   const void *info,
 271                                   unsigned int size, unsigned int user_size)
 272{
 273        unsigned int info_size, aligned_size = XT_ALIGN(size);
 274        struct nlattr *nla;
 275
 276        nla = nla_reserve(skb, attr, aligned_size);
 277        if (!nla)
 278                return -1;
 279
 280        info_size = user_size ? : size;
 281        memcpy(nla_data(nla), info, info_size);
 282        memset(nla_data(nla) + info_size, 0, aligned_size - info_size);
 283
 284        return 0;
 285}
 286
 287static int nft_target_dump(struct sk_buff *skb, const struct nft_expr *expr)
 288{
 289        const struct xt_target *target = expr->ops->data;
 290        void *info = nft_expr_priv(expr);
 291
 292        if (nla_put_string(skb, NFTA_TARGET_NAME, target->name) ||
 293            nla_put_be32(skb, NFTA_TARGET_REV, htonl(target->revision)) ||
 294            nft_extension_dump_info(skb, NFTA_TARGET_INFO, info,
 295                                    target->targetsize, target->usersize))
 296                goto nla_put_failure;
 297
 298        return 0;
 299
 300nla_put_failure:
 301        return -1;
 302}
 303
 304static int nft_target_validate(const struct nft_ctx *ctx,
 305                               const struct nft_expr *expr,
 306                               const struct nft_data **data)
 307{
 308        struct xt_target *target = expr->ops->data;
 309        unsigned int hook_mask = 0;
 310        int ret;
 311
 312        if (nft_is_base_chain(ctx->chain)) {
 313                const struct nft_base_chain *basechain =
 314                                                nft_base_chain(ctx->chain);
 315                const struct nf_hook_ops *ops = &basechain->ops;
 316
 317                hook_mask = 1 << ops->hooknum;
 318                if (target->hooks && !(hook_mask & target->hooks))
 319                        return -EINVAL;
 320
 321                ret = nft_compat_chain_validate_dependency(ctx, target->table);
 322                if (ret < 0)
 323                        return ret;
 324        }
 325        return 0;
 326}
 327
 328static void __nft_match_eval(const struct nft_expr *expr,
 329                             struct nft_regs *regs,
 330                             const struct nft_pktinfo *pkt,
 331                             void *info)
 332{
 333        struct xt_match *match = expr->ops->data;
 334        struct sk_buff *skb = pkt->skb;
 335        bool ret;
 336
 337        nft_compat_set_par((struct xt_action_param *)&pkt->xt, match, info);
 338
 339        ret = match->match(skb, (struct xt_action_param *)&pkt->xt);
 340
 341        if (pkt->xt.hotdrop) {
 342                regs->verdict.code = NF_DROP;
 343                return;
 344        }
 345
 346        switch (ret ? 1 : 0) {
 347        case 1:
 348                regs->verdict.code = NFT_CONTINUE;
 349                break;
 350        case 0:
 351                regs->verdict.code = NFT_BREAK;
 352                break;
 353        }
 354}
 355
 356static void nft_match_large_eval(const struct nft_expr *expr,
 357                                 struct nft_regs *regs,
 358                                 const struct nft_pktinfo *pkt)
 359{
 360        struct nft_xt_match_priv *priv = nft_expr_priv(expr);
 361
 362        __nft_match_eval(expr, regs, pkt, priv->info);
 363}
 364
 365static void nft_match_eval(const struct nft_expr *expr,
 366                           struct nft_regs *regs,
 367                           const struct nft_pktinfo *pkt)
 368{
 369        __nft_match_eval(expr, regs, pkt, nft_expr_priv(expr));
 370}
 371
 372static const struct nla_policy nft_match_policy[NFTA_MATCH_MAX + 1] = {
 373        [NFTA_MATCH_NAME]       = { .type = NLA_NUL_STRING },
 374        [NFTA_MATCH_REV]        = { .type = NLA_U32 },
 375        [NFTA_MATCH_INFO]       = { .type = NLA_BINARY },
 376};
 377
 378/* struct xt_mtchk_param and xt_tgchk_param look very similar */
 379static void
 380nft_match_set_mtchk_param(struct xt_mtchk_param *par, const struct nft_ctx *ctx,
 381                          struct xt_match *match, void *info,
 382                          union nft_entry *entry, u16 proto, bool inv)
 383{
 384        par->net        = ctx->net;
 385        par->table      = ctx->table->name;
 386        switch (ctx->family) {
 387        case AF_INET:
 388                entry->e4.ip.proto = proto;
 389                entry->e4.ip.invflags = inv ? IPT_INV_PROTO : 0;
 390                break;
 391        case AF_INET6:
 392                if (proto)
 393                        entry->e6.ipv6.flags |= IP6T_F_PROTO;
 394
 395                entry->e6.ipv6.proto = proto;
 396                entry->e6.ipv6.invflags = inv ? IP6T_INV_PROTO : 0;
 397                break;
 398        case NFPROTO_BRIDGE:
 399                entry->ebt.ethproto = (__force __be16)proto;
 400                entry->ebt.invflags = inv ? EBT_IPROTO : 0;
 401                break;
 402        case NFPROTO_ARP:
 403                break;
 404        }
 405        par->entryinfo  = entry;
 406        par->match      = match;
 407        par->matchinfo  = info;
 408        if (nft_is_base_chain(ctx->chain)) {
 409                const struct nft_base_chain *basechain =
 410                                                nft_base_chain(ctx->chain);
 411                const struct nf_hook_ops *ops = &basechain->ops;
 412
 413                par->hook_mask = 1 << ops->hooknum;
 414        } else {
 415                par->hook_mask = 0;
 416        }
 417        par->family     = ctx->family;
 418        par->nft_compat = true;
 419}
 420
 421static void match_compat_from_user(struct xt_match *m, void *in, void *out)
 422{
 423        int pad;
 424
 425        memcpy(out, in, m->matchsize);
 426        pad = XT_ALIGN(m->matchsize) - m->matchsize;
 427        if (pad > 0)
 428                memset(out + m->matchsize, 0, pad);
 429}
 430
 431static int
 432__nft_match_init(const struct nft_ctx *ctx, const struct nft_expr *expr,
 433                 const struct nlattr * const tb[],
 434                 void *info)
 435{
 436        struct xt_match *match = expr->ops->data;
 437        struct xt_mtchk_param par;
 438        size_t size = XT_ALIGN(nla_len(tb[NFTA_MATCH_INFO]));
 439        u16 proto = 0;
 440        bool inv = false;
 441        union nft_entry e = {};
 442        int ret;
 443
 444        match_compat_from_user(match, nla_data(tb[NFTA_MATCH_INFO]), info);
 445
 446        if (ctx->nla[NFTA_RULE_COMPAT]) {
 447                ret = nft_parse_compat(ctx->nla[NFTA_RULE_COMPAT], &proto, &inv);
 448                if (ret < 0)
 449                        return ret;
 450        }
 451
 452        nft_match_set_mtchk_param(&par, ctx, match, info, &e, proto, inv);
 453
 454        return xt_check_match(&par, size, proto, inv);
 455}
 456
 457static int
 458nft_match_init(const struct nft_ctx *ctx, const struct nft_expr *expr,
 459               const struct nlattr * const tb[])
 460{
 461        return __nft_match_init(ctx, expr, tb, nft_expr_priv(expr));
 462}
 463
 464static int
 465nft_match_large_init(const struct nft_ctx *ctx, const struct nft_expr *expr,
 466                     const struct nlattr * const tb[])
 467{
 468        struct nft_xt_match_priv *priv = nft_expr_priv(expr);
 469        struct xt_match *m = expr->ops->data;
 470        int ret;
 471
 472        priv->info = kmalloc(XT_ALIGN(m->matchsize), GFP_KERNEL);
 473        if (!priv->info)
 474                return -ENOMEM;
 475
 476        ret = __nft_match_init(ctx, expr, tb, priv->info);
 477        if (ret)
 478                kfree(priv->info);
 479        return ret;
 480}
 481
 482static void
 483__nft_match_destroy(const struct nft_ctx *ctx, const struct nft_expr *expr,
 484                    void *info)
 485{
 486        struct xt_match *match = expr->ops->data;
 487        struct module *me = match->me;
 488        struct xt_mtdtor_param par;
 489
 490        par.net = ctx->net;
 491        par.match = match;
 492        par.matchinfo = info;
 493        par.family = ctx->family;
 494        if (par.match->destroy != NULL)
 495                par.match->destroy(&par);
 496
 497        module_put(me);
 498        kfree(expr->ops);
 499}
 500
 501static void
 502nft_match_destroy(const struct nft_ctx *ctx, const struct nft_expr *expr)
 503{
 504        __nft_match_destroy(ctx, expr, nft_expr_priv(expr));
 505}
 506
 507static void
 508nft_match_large_destroy(const struct nft_ctx *ctx, const struct nft_expr *expr)
 509{
 510        struct nft_xt_match_priv *priv = nft_expr_priv(expr);
 511
 512        __nft_match_destroy(ctx, expr, priv->info);
 513        kfree(priv->info);
 514}
 515
 516static int __nft_match_dump(struct sk_buff *skb, const struct nft_expr *expr,
 517                            void *info)
 518{
 519        struct xt_match *match = expr->ops->data;
 520
 521        if (nla_put_string(skb, NFTA_MATCH_NAME, match->name) ||
 522            nla_put_be32(skb, NFTA_MATCH_REV, htonl(match->revision)) ||
 523            nft_extension_dump_info(skb, NFTA_MATCH_INFO, info,
 524                                    match->matchsize, match->usersize))
 525                goto nla_put_failure;
 526
 527        return 0;
 528
 529nla_put_failure:
 530        return -1;
 531}
 532
 533static int nft_match_dump(struct sk_buff *skb, const struct nft_expr *expr)
 534{
 535        return __nft_match_dump(skb, expr, nft_expr_priv(expr));
 536}
 537
 538static int nft_match_large_dump(struct sk_buff *skb, const struct nft_expr *e)
 539{
 540        struct nft_xt_match_priv *priv = nft_expr_priv(e);
 541
 542        return __nft_match_dump(skb, e, priv->info);
 543}
 544
 545static int nft_match_validate(const struct nft_ctx *ctx,
 546                              const struct nft_expr *expr,
 547                              const struct nft_data **data)
 548{
 549        struct xt_match *match = expr->ops->data;
 550        unsigned int hook_mask = 0;
 551        int ret;
 552
 553        if (nft_is_base_chain(ctx->chain)) {
 554                const struct nft_base_chain *basechain =
 555                                                nft_base_chain(ctx->chain);
 556                const struct nf_hook_ops *ops = &basechain->ops;
 557
 558                hook_mask = 1 << ops->hooknum;
 559                if (match->hooks && !(hook_mask & match->hooks))
 560                        return -EINVAL;
 561
 562                ret = nft_compat_chain_validate_dependency(ctx, match->table);
 563                if (ret < 0)
 564                        return ret;
 565        }
 566        return 0;
 567}
 568
 569static int
 570nfnl_compat_fill_info(struct sk_buff *skb, u32 portid, u32 seq, u32 type,
 571                      int event, u16 family, const char *name,
 572                      int rev, int target)
 573{
 574        struct nlmsghdr *nlh;
 575        struct nfgenmsg *nfmsg;
 576        unsigned int flags = portid ? NLM_F_MULTI : 0;
 577
 578        event = nfnl_msg_type(NFNL_SUBSYS_NFT_COMPAT, event);
 579        nlh = nlmsg_put(skb, portid, seq, event, sizeof(*nfmsg), flags);
 580        if (nlh == NULL)
 581                goto nlmsg_failure;
 582
 583        nfmsg = nlmsg_data(nlh);
 584        nfmsg->nfgen_family = family;
 585        nfmsg->version = NFNETLINK_V0;
 586        nfmsg->res_id = 0;
 587
 588        if (nla_put_string(skb, NFTA_COMPAT_NAME, name) ||
 589            nla_put_be32(skb, NFTA_COMPAT_REV, htonl(rev)) ||
 590            nla_put_be32(skb, NFTA_COMPAT_TYPE, htonl(target)))
 591                goto nla_put_failure;
 592
 593        nlmsg_end(skb, nlh);
 594        return skb->len;
 595
 596nlmsg_failure:
 597nla_put_failure:
 598        nlmsg_cancel(skb, nlh);
 599        return -1;
 600}
 601
 602static int nfnl_compat_get_rcu(struct net *net, struct sock *nfnl,
 603                               struct sk_buff *skb, const struct nlmsghdr *nlh,
 604                               const struct nlattr * const tb[],
 605                               struct netlink_ext_ack *extack)
 606{
 607        int ret = 0, target;
 608        struct nfgenmsg *nfmsg;
 609        const char *fmt;
 610        const char *name;
 611        u32 rev;
 612        struct sk_buff *skb2;
 613
 614        if (tb[NFTA_COMPAT_NAME] == NULL ||
 615            tb[NFTA_COMPAT_REV] == NULL ||
 616            tb[NFTA_COMPAT_TYPE] == NULL)
 617                return -EINVAL;
 618
 619        name = nla_data(tb[NFTA_COMPAT_NAME]);
 620        rev = ntohl(nla_get_be32(tb[NFTA_COMPAT_REV]));
 621        target = ntohl(nla_get_be32(tb[NFTA_COMPAT_TYPE]));
 622
 623        nfmsg = nlmsg_data(nlh);
 624
 625        switch(nfmsg->nfgen_family) {
 626        case AF_INET:
 627                fmt = "ipt_%s";
 628                break;
 629        case AF_INET6:
 630                fmt = "ip6t_%s";
 631                break;
 632        case NFPROTO_BRIDGE:
 633                fmt = "ebt_%s";
 634                break;
 635        case NFPROTO_ARP:
 636                fmt = "arpt_%s";
 637                break;
 638        default:
 639                pr_err("nft_compat: unsupported protocol %d\n",
 640                        nfmsg->nfgen_family);
 641                return -EINVAL;
 642        }
 643
 644        if (!try_module_get(THIS_MODULE))
 645                return -EINVAL;
 646
 647        rcu_read_unlock();
 648        try_then_request_module(xt_find_revision(nfmsg->nfgen_family, name,
 649                                                 rev, target, &ret),
 650                                                 fmt, name);
 651        if (ret < 0)
 652                goto out_put;
 653
 654        skb2 = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 655        if (skb2 == NULL) {
 656                ret = -ENOMEM;
 657                goto out_put;
 658        }
 659
 660        /* include the best revision for this extension in the message */
 661        if (nfnl_compat_fill_info(skb2, NETLINK_CB(skb).portid,
 662                                  nlh->nlmsg_seq,
 663                                  NFNL_MSG_TYPE(nlh->nlmsg_type),
 664                                  NFNL_MSG_COMPAT_GET,
 665                                  nfmsg->nfgen_family,
 666                                  name, ret, target) <= 0) {
 667                kfree_skb(skb2);
 668                goto out_put;
 669        }
 670
 671        ret = netlink_unicast(nfnl, skb2, NETLINK_CB(skb).portid,
 672                                MSG_DONTWAIT);
 673        if (ret > 0)
 674                ret = 0;
 675out_put:
 676        rcu_read_lock();
 677        module_put(THIS_MODULE);
 678        return ret == -EAGAIN ? -ENOBUFS : ret;
 679}
 680
 681static const struct nla_policy nfnl_compat_policy_get[NFTA_COMPAT_MAX+1] = {
 682        [NFTA_COMPAT_NAME]      = { .type = NLA_NUL_STRING,
 683                                    .len = NFT_COMPAT_NAME_MAX-1 },
 684        [NFTA_COMPAT_REV]       = { .type = NLA_U32 },
 685        [NFTA_COMPAT_TYPE]      = { .type = NLA_U32 },
 686};
 687
 688static const struct nfnl_callback nfnl_nft_compat_cb[NFNL_MSG_COMPAT_MAX] = {
 689        [NFNL_MSG_COMPAT_GET]           = { .call_rcu = nfnl_compat_get_rcu,
 690                                            .attr_count = NFTA_COMPAT_MAX,
 691                                            .policy = nfnl_compat_policy_get },
 692};
 693
 694static const struct nfnetlink_subsystem nfnl_compat_subsys = {
 695        .name           = "nft-compat",
 696        .subsys_id      = NFNL_SUBSYS_NFT_COMPAT,
 697        .cb_count       = NFNL_MSG_COMPAT_MAX,
 698        .cb             = nfnl_nft_compat_cb,
 699};
 700
 701static struct nft_expr_type nft_match_type;
 702
 703static const struct nft_expr_ops *
 704nft_match_select_ops(const struct nft_ctx *ctx,
 705                     const struct nlattr * const tb[])
 706{
 707        struct nft_expr_ops *ops;
 708        struct xt_match *match;
 709        unsigned int matchsize;
 710        char *mt_name;
 711        u32 rev, family;
 712        int err;
 713
 714        if (tb[NFTA_MATCH_NAME] == NULL ||
 715            tb[NFTA_MATCH_REV] == NULL ||
 716            tb[NFTA_MATCH_INFO] == NULL)
 717                return ERR_PTR(-EINVAL);
 718
 719        mt_name = nla_data(tb[NFTA_MATCH_NAME]);
 720        rev = ntohl(nla_get_be32(tb[NFTA_MATCH_REV]));
 721        family = ctx->family;
 722
 723        match = xt_request_find_match(family, mt_name, rev);
 724        if (IS_ERR(match))
 725                return ERR_PTR(-ENOENT);
 726
 727        if (match->matchsize > nla_len(tb[NFTA_MATCH_INFO])) {
 728                err = -EINVAL;
 729                goto err;
 730        }
 731
 732        ops = kzalloc(sizeof(struct nft_expr_ops), GFP_KERNEL);
 733        if (!ops) {
 734                err = -ENOMEM;
 735                goto err;
 736        }
 737
 738        ops->type = &nft_match_type;
 739        ops->eval = nft_match_eval;
 740        ops->init = nft_match_init;
 741        ops->destroy = nft_match_destroy;
 742        ops->dump = nft_match_dump;
 743        ops->validate = nft_match_validate;
 744        ops->data = match;
 745
 746        matchsize = NFT_EXPR_SIZE(XT_ALIGN(match->matchsize));
 747        if (matchsize > NFT_MATCH_LARGE_THRESH) {
 748                matchsize = NFT_EXPR_SIZE(sizeof(struct nft_xt_match_priv));
 749
 750                ops->eval = nft_match_large_eval;
 751                ops->init = nft_match_large_init;
 752                ops->destroy = nft_match_large_destroy;
 753                ops->dump = nft_match_large_dump;
 754        }
 755
 756        ops->size = matchsize;
 757
 758        return ops;
 759err:
 760        module_put(match->me);
 761        return ERR_PTR(err);
 762}
 763
 764static void nft_match_release_ops(const struct nft_expr_ops *ops)
 765{
 766        struct xt_match *match = ops->data;
 767
 768        module_put(match->me);
 769        kfree(ops);
 770}
 771
 772static struct nft_expr_type nft_match_type __read_mostly = {
 773        .name           = "match",
 774        .select_ops     = nft_match_select_ops,
 775        .release_ops    = nft_match_release_ops,
 776        .policy         = nft_match_policy,
 777        .maxattr        = NFTA_MATCH_MAX,
 778        .owner          = THIS_MODULE,
 779};
 780
 781static struct nft_expr_type nft_target_type;
 782
 783static const struct nft_expr_ops *
 784nft_target_select_ops(const struct nft_ctx *ctx,
 785                      const struct nlattr * const tb[])
 786{
 787        struct nft_expr_ops *ops;
 788        struct xt_target *target;
 789        char *tg_name;
 790        u32 rev, family;
 791        int err;
 792
 793        if (tb[NFTA_TARGET_NAME] == NULL ||
 794            tb[NFTA_TARGET_REV] == NULL ||
 795            tb[NFTA_TARGET_INFO] == NULL)
 796                return ERR_PTR(-EINVAL);
 797
 798        tg_name = nla_data(tb[NFTA_TARGET_NAME]);
 799        rev = ntohl(nla_get_be32(tb[NFTA_TARGET_REV]));
 800        family = ctx->family;
 801
 802        if (strcmp(tg_name, XT_ERROR_TARGET) == 0 ||
 803            strcmp(tg_name, XT_STANDARD_TARGET) == 0 ||
 804            strcmp(tg_name, "standard") == 0)
 805                return ERR_PTR(-EINVAL);
 806
 807        target = xt_request_find_target(family, tg_name, rev);
 808        if (IS_ERR(target))
 809                return ERR_PTR(-ENOENT);
 810
 811        if (!target->target) {
 812                err = -EINVAL;
 813                goto err;
 814        }
 815
 816        if (target->targetsize > nla_len(tb[NFTA_TARGET_INFO])) {
 817                err = -EINVAL;
 818                goto err;
 819        }
 820
 821        ops = kzalloc(sizeof(struct nft_expr_ops), GFP_KERNEL);
 822        if (!ops) {
 823                err = -ENOMEM;
 824                goto err;
 825        }
 826
 827        ops->type = &nft_target_type;
 828        ops->size = NFT_EXPR_SIZE(XT_ALIGN(target->targetsize));
 829        ops->init = nft_target_init;
 830        ops->destroy = nft_target_destroy;
 831        ops->dump = nft_target_dump;
 832        ops->validate = nft_target_validate;
 833        ops->data = target;
 834
 835        if (family == NFPROTO_BRIDGE)
 836                ops->eval = nft_target_eval_bridge;
 837        else
 838                ops->eval = nft_target_eval_xt;
 839
 840        return ops;
 841err:
 842        module_put(target->me);
 843        return ERR_PTR(err);
 844}
 845
 846static void nft_target_release_ops(const struct nft_expr_ops *ops)
 847{
 848        struct xt_target *target = ops->data;
 849
 850        module_put(target->me);
 851        kfree(ops);
 852}
 853
 854static struct nft_expr_type nft_target_type __read_mostly = {
 855        .name           = "target",
 856        .select_ops     = nft_target_select_ops,
 857        .release_ops    = nft_target_release_ops,
 858        .policy         = nft_target_policy,
 859        .maxattr        = NFTA_TARGET_MAX,
 860        .owner          = THIS_MODULE,
 861};
 862
 863static int __init nft_compat_module_init(void)
 864{
 865        int ret;
 866
 867        ret = nft_register_expr(&nft_match_type);
 868        if (ret < 0)
 869                return ret;
 870
 871        ret = nft_register_expr(&nft_target_type);
 872        if (ret < 0)
 873                goto err_match;
 874
 875        ret = nfnetlink_subsys_register(&nfnl_compat_subsys);
 876        if (ret < 0) {
 877                pr_err("nft_compat: cannot register with nfnetlink.\n");
 878                goto err_target;
 879        }
 880
 881        return ret;
 882err_target:
 883        nft_unregister_expr(&nft_target_type);
 884err_match:
 885        nft_unregister_expr(&nft_match_type);
 886        return ret;
 887}
 888
 889static void __exit nft_compat_module_exit(void)
 890{
 891        nfnetlink_subsys_unregister(&nfnl_compat_subsys);
 892        nft_unregister_expr(&nft_target_type);
 893        nft_unregister_expr(&nft_match_type);
 894}
 895
 896MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_NFT_COMPAT);
 897
 898module_init(nft_compat_module_init);
 899module_exit(nft_compat_module_exit);
 900
 901MODULE_LICENSE("GPL");
 902MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
 903MODULE_ALIAS_NFT_EXPR("match");
 904MODULE_ALIAS_NFT_EXPR("target");
 905