linux/net/netfilter/x_tables.c
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   1/*
   2 * x_tables core - Backend for {ip,ip6,arp}_tables
   3 *
   4 * Copyright (C) 2006-2006 Harald Welte <laforge@netfilter.org>
   5 *
   6 * Based on existing ip_tables code which is
   7 *   Copyright (C) 1999 Paul `Rusty' Russell & Michael J. Neuling
   8 *   Copyright (C) 2000-2005 Netfilter Core Team <coreteam@netfilter.org>
   9 *
  10 * This program is free software; you can redistribute it and/or modify
  11 * it under the terms of the GNU General Public License version 2 as
  12 * published by the Free Software Foundation.
  13 *
  14 */
  15#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  16#include <linux/kernel.h>
  17#include <linux/module.h>
  18#include <linux/socket.h>
  19#include <linux/net.h>
  20#include <linux/proc_fs.h>
  21#include <linux/seq_file.h>
  22#include <linux/string.h>
  23#include <linux/vmalloc.h>
  24#include <linux/mutex.h>
  25#include <linux/mm.h>
  26#include <linux/slab.h>
  27#include <linux/audit.h>
  28#include <net/net_namespace.h>
  29
  30#include <linux/netfilter/x_tables.h>
  31#include <linux/netfilter_arp.h>
  32#include <linux/netfilter_ipv4/ip_tables.h>
  33#include <linux/netfilter_ipv6/ip6_tables.h>
  34#include <linux/netfilter_arp/arp_tables.h>
  35
  36MODULE_LICENSE("GPL");
  37MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
  38MODULE_DESCRIPTION("{ip,ip6,arp,eb}_tables backend module");
  39
  40#define SMP_ALIGN(x) (((x) + SMP_CACHE_BYTES-1) & ~(SMP_CACHE_BYTES-1))
  41
  42struct compat_delta {
  43        unsigned int offset; /* offset in kernel */
  44        int delta; /* delta in 32bit user land */
  45};
  46
  47struct xt_af {
  48        struct mutex mutex;
  49        struct list_head match;
  50        struct list_head target;
  51#ifdef CONFIG_COMPAT
  52        struct mutex compat_mutex;
  53        struct compat_delta *compat_tab;
  54        unsigned int number; /* number of slots in compat_tab[] */
  55        unsigned int cur; /* number of used slots in compat_tab[] */
  56#endif
  57};
  58
  59static struct xt_af *xt;
  60
  61static const char *const xt_prefix[NFPROTO_NUMPROTO] = {
  62        [NFPROTO_UNSPEC] = "x",
  63        [NFPROTO_IPV4]   = "ip",
  64        [NFPROTO_ARP]    = "arp",
  65        [NFPROTO_BRIDGE] = "eb",
  66        [NFPROTO_IPV6]   = "ip6",
  67};
  68
  69/* Allow this many total (re)entries. */
  70static const unsigned int xt_jumpstack_multiplier = 2;
  71
  72/* Registration hooks for targets. */
  73int
  74xt_register_target(struct xt_target *target)
  75{
  76        u_int8_t af = target->family;
  77        int ret;
  78
  79        ret = mutex_lock_interruptible(&xt[af].mutex);
  80        if (ret != 0)
  81                return ret;
  82        list_add(&target->list, &xt[af].target);
  83        mutex_unlock(&xt[af].mutex);
  84        return ret;
  85}
  86EXPORT_SYMBOL(xt_register_target);
  87
  88void
  89xt_unregister_target(struct xt_target *target)
  90{
  91        u_int8_t af = target->family;
  92
  93        mutex_lock(&xt[af].mutex);
  94        list_del(&target->list);
  95        mutex_unlock(&xt[af].mutex);
  96}
  97EXPORT_SYMBOL(xt_unregister_target);
  98
  99int
 100xt_register_targets(struct xt_target *target, unsigned int n)
 101{
 102        unsigned int i;
 103        int err = 0;
 104
 105        for (i = 0; i < n; i++) {
 106                err = xt_register_target(&target[i]);
 107                if (err)
 108                        goto err;
 109        }
 110        return err;
 111
 112err:
 113        if (i > 0)
 114                xt_unregister_targets(target, i);
 115        return err;
 116}
 117EXPORT_SYMBOL(xt_register_targets);
 118
 119void
 120xt_unregister_targets(struct xt_target *target, unsigned int n)
 121{
 122        while (n-- > 0)
 123                xt_unregister_target(&target[n]);
 124}
 125EXPORT_SYMBOL(xt_unregister_targets);
 126
 127int
 128xt_register_match(struct xt_match *match)
 129{
 130        u_int8_t af = match->family;
 131        int ret;
 132
 133        ret = mutex_lock_interruptible(&xt[af].mutex);
 134        if (ret != 0)
 135                return ret;
 136
 137        list_add(&match->list, &xt[af].match);
 138        mutex_unlock(&xt[af].mutex);
 139
 140        return ret;
 141}
 142EXPORT_SYMBOL(xt_register_match);
 143
 144void
 145xt_unregister_match(struct xt_match *match)
 146{
 147        u_int8_t af = match->family;
 148
 149        mutex_lock(&xt[af].mutex);
 150        list_del(&match->list);
 151        mutex_unlock(&xt[af].mutex);
 152}
 153EXPORT_SYMBOL(xt_unregister_match);
 154
 155int
 156xt_register_matches(struct xt_match *match, unsigned int n)
 157{
 158        unsigned int i;
 159        int err = 0;
 160
 161        for (i = 0; i < n; i++) {
 162                err = xt_register_match(&match[i]);
 163                if (err)
 164                        goto err;
 165        }
 166        return err;
 167
 168err:
 169        if (i > 0)
 170                xt_unregister_matches(match, i);
 171        return err;
 172}
 173EXPORT_SYMBOL(xt_register_matches);
 174
 175void
 176xt_unregister_matches(struct xt_match *match, unsigned int n)
 177{
 178        while (n-- > 0)
 179                xt_unregister_match(&match[n]);
 180}
 181EXPORT_SYMBOL(xt_unregister_matches);
 182
 183
 184/*
 185 * These are weird, but module loading must not be done with mutex
 186 * held (since they will register), and we have to have a single
 187 * function to use.
 188 */
 189
 190/* Find match, grabs ref.  Returns ERR_PTR() on error. */
 191struct xt_match *xt_find_match(u8 af, const char *name, u8 revision)
 192{
 193        struct xt_match *m;
 194        int err = -ENOENT;
 195
 196        if (mutex_lock_interruptible(&xt[af].mutex) != 0)
 197                return ERR_PTR(-EINTR);
 198
 199        list_for_each_entry(m, &xt[af].match, list) {
 200                if (strcmp(m->name, name) == 0) {
 201                        if (m->revision == revision) {
 202                                if (try_module_get(m->me)) {
 203                                        mutex_unlock(&xt[af].mutex);
 204                                        return m;
 205                                }
 206                        } else
 207                                err = -EPROTOTYPE; /* Found something. */
 208                }
 209        }
 210        mutex_unlock(&xt[af].mutex);
 211
 212        if (af != NFPROTO_UNSPEC)
 213                /* Try searching again in the family-independent list */
 214                return xt_find_match(NFPROTO_UNSPEC, name, revision);
 215
 216        return ERR_PTR(err);
 217}
 218EXPORT_SYMBOL(xt_find_match);
 219
 220struct xt_match *
 221xt_request_find_match(uint8_t nfproto, const char *name, uint8_t revision)
 222{
 223        struct xt_match *match;
 224
 225        match = xt_find_match(nfproto, name, revision);
 226        if (IS_ERR(match)) {
 227                request_module("%st_%s", xt_prefix[nfproto], name);
 228                match = xt_find_match(nfproto, name, revision);
 229        }
 230
 231        return match;
 232}
 233EXPORT_SYMBOL_GPL(xt_request_find_match);
 234
 235/* Find target, grabs ref.  Returns ERR_PTR() on error. */
 236struct xt_target *xt_find_target(u8 af, const char *name, u8 revision)
 237{
 238        struct xt_target *t;
 239        int err = -ENOENT;
 240
 241        if (mutex_lock_interruptible(&xt[af].mutex) != 0)
 242                return ERR_PTR(-EINTR);
 243
 244        list_for_each_entry(t, &xt[af].target, list) {
 245                if (strcmp(t->name, name) == 0) {
 246                        if (t->revision == revision) {
 247                                if (try_module_get(t->me)) {
 248                                        mutex_unlock(&xt[af].mutex);
 249                                        return t;
 250                                }
 251                        } else
 252                                err = -EPROTOTYPE; /* Found something. */
 253                }
 254        }
 255        mutex_unlock(&xt[af].mutex);
 256
 257        if (af != NFPROTO_UNSPEC)
 258                /* Try searching again in the family-independent list */
 259                return xt_find_target(NFPROTO_UNSPEC, name, revision);
 260
 261        return ERR_PTR(err);
 262}
 263EXPORT_SYMBOL(xt_find_target);
 264
 265struct xt_target *xt_request_find_target(u8 af, const char *name, u8 revision)
 266{
 267        struct xt_target *target;
 268
 269        target = xt_find_target(af, name, revision);
 270        if (IS_ERR(target)) {
 271                request_module("%st_%s", xt_prefix[af], name);
 272                target = xt_find_target(af, name, revision);
 273        }
 274
 275        return target;
 276}
 277EXPORT_SYMBOL_GPL(xt_request_find_target);
 278
 279static int match_revfn(u8 af, const char *name, u8 revision, int *bestp)
 280{
 281        const struct xt_match *m;
 282        int have_rev = 0;
 283
 284        list_for_each_entry(m, &xt[af].match, list) {
 285                if (strcmp(m->name, name) == 0) {
 286                        if (m->revision > *bestp)
 287                                *bestp = m->revision;
 288                        if (m->revision == revision)
 289                                have_rev = 1;
 290                }
 291        }
 292
 293        if (af != NFPROTO_UNSPEC && !have_rev)
 294                return match_revfn(NFPROTO_UNSPEC, name, revision, bestp);
 295
 296        return have_rev;
 297}
 298
 299static int target_revfn(u8 af, const char *name, u8 revision, int *bestp)
 300{
 301        const struct xt_target *t;
 302        int have_rev = 0;
 303
 304        list_for_each_entry(t, &xt[af].target, list) {
 305                if (strcmp(t->name, name) == 0) {
 306                        if (t->revision > *bestp)
 307                                *bestp = t->revision;
 308                        if (t->revision == revision)
 309                                have_rev = 1;
 310                }
 311        }
 312
 313        if (af != NFPROTO_UNSPEC && !have_rev)
 314                return target_revfn(NFPROTO_UNSPEC, name, revision, bestp);
 315
 316        return have_rev;
 317}
 318
 319/* Returns true or false (if no such extension at all) */
 320int xt_find_revision(u8 af, const char *name, u8 revision, int target,
 321                     int *err)
 322{
 323        int have_rev, best = -1;
 324
 325        if (mutex_lock_interruptible(&xt[af].mutex) != 0) {
 326                *err = -EINTR;
 327                return 1;
 328        }
 329        if (target == 1)
 330                have_rev = target_revfn(af, name, revision, &best);
 331        else
 332                have_rev = match_revfn(af, name, revision, &best);
 333        mutex_unlock(&xt[af].mutex);
 334
 335        /* Nothing at all?  Return 0 to try loading module. */
 336        if (best == -1) {
 337                *err = -ENOENT;
 338                return 0;
 339        }
 340
 341        *err = best;
 342        if (!have_rev)
 343                *err = -EPROTONOSUPPORT;
 344        return 1;
 345}
 346EXPORT_SYMBOL_GPL(xt_find_revision);
 347
 348static char *textify_hooks(char *buf, size_t size, unsigned int mask)
 349{
 350        static const char *const names[] = {
 351                "PREROUTING", "INPUT", "FORWARD",
 352                "OUTPUT", "POSTROUTING", "BROUTING",
 353        };
 354        unsigned int i;
 355        char *p = buf;
 356        bool np = false;
 357        int res;
 358
 359        *p = '\0';
 360        for (i = 0; i < ARRAY_SIZE(names); ++i) {
 361                if (!(mask & (1 << i)))
 362                        continue;
 363                res = snprintf(p, size, "%s%s", np ? "/" : "", names[i]);
 364                if (res > 0) {
 365                        size -= res;
 366                        p += res;
 367                }
 368                np = true;
 369        }
 370
 371        return buf;
 372}
 373
 374int xt_check_match(struct xt_mtchk_param *par,
 375                   unsigned int size, u_int8_t proto, bool inv_proto)
 376{
 377        int ret;
 378
 379        if (XT_ALIGN(par->match->matchsize) != size &&
 380            par->match->matchsize != -1) {
 381                /*
 382                 * ebt_among is exempt from centralized matchsize checking
 383                 * because it uses a dynamic-size data set.
 384                 */
 385                pr_err("%s_tables: %s.%u match: invalid size "
 386                       "%u (kernel) != (user) %u\n",
 387                       xt_prefix[par->family], par->match->name,
 388                       par->match->revision,
 389                       XT_ALIGN(par->match->matchsize), size);
 390                return -EINVAL;
 391        }
 392        if (par->match->table != NULL &&
 393            strcmp(par->match->table, par->table) != 0) {
 394                pr_err("%s_tables: %s match: only valid in %s table, not %s\n",
 395                       xt_prefix[par->family], par->match->name,
 396                       par->match->table, par->table);
 397                return -EINVAL;
 398        }
 399        if (par->match->hooks && (par->hook_mask & ~par->match->hooks) != 0) {
 400                char used[64], allow[64];
 401
 402                pr_err("%s_tables: %s match: used from hooks %s, but only "
 403                       "valid from %s\n",
 404                       xt_prefix[par->family], par->match->name,
 405                       textify_hooks(used, sizeof(used), par->hook_mask),
 406                       textify_hooks(allow, sizeof(allow), par->match->hooks));
 407                return -EINVAL;
 408        }
 409        if (par->match->proto && (par->match->proto != proto || inv_proto)) {
 410                pr_err("%s_tables: %s match: only valid for protocol %u\n",
 411                       xt_prefix[par->family], par->match->name,
 412                       par->match->proto);
 413                return -EINVAL;
 414        }
 415        if (par->match->checkentry != NULL) {
 416                ret = par->match->checkentry(par);
 417                if (ret < 0)
 418                        return ret;
 419                else if (ret > 0)
 420                        /* Flag up potential errors. */
 421                        return -EIO;
 422        }
 423        return 0;
 424}
 425EXPORT_SYMBOL_GPL(xt_check_match);
 426
 427#ifdef CONFIG_COMPAT
 428int xt_compat_add_offset(u_int8_t af, unsigned int offset, int delta)
 429{
 430        struct xt_af *xp = &xt[af];
 431
 432        if (!xp->compat_tab) {
 433                if (!xp->number)
 434                        return -EINVAL;
 435                xp->compat_tab = vmalloc(sizeof(struct compat_delta) * xp->number);
 436                if (!xp->compat_tab)
 437                        return -ENOMEM;
 438                xp->cur = 0;
 439        }
 440
 441        if (xp->cur >= xp->number)
 442                return -EINVAL;
 443
 444        if (xp->cur)
 445                delta += xp->compat_tab[xp->cur - 1].delta;
 446        xp->compat_tab[xp->cur].offset = offset;
 447        xp->compat_tab[xp->cur].delta = delta;
 448        xp->cur++;
 449        return 0;
 450}
 451EXPORT_SYMBOL_GPL(xt_compat_add_offset);
 452
 453void xt_compat_flush_offsets(u_int8_t af)
 454{
 455        if (xt[af].compat_tab) {
 456                vfree(xt[af].compat_tab);
 457                xt[af].compat_tab = NULL;
 458                xt[af].number = 0;
 459                xt[af].cur = 0;
 460        }
 461}
 462EXPORT_SYMBOL_GPL(xt_compat_flush_offsets);
 463
 464int xt_compat_calc_jump(u_int8_t af, unsigned int offset)
 465{
 466        struct compat_delta *tmp = xt[af].compat_tab;
 467        int mid, left = 0, right = xt[af].cur - 1;
 468
 469        while (left <= right) {
 470                mid = (left + right) >> 1;
 471                if (offset > tmp[mid].offset)
 472                        left = mid + 1;
 473                else if (offset < tmp[mid].offset)
 474                        right = mid - 1;
 475                else
 476                        return mid ? tmp[mid - 1].delta : 0;
 477        }
 478        return left ? tmp[left - 1].delta : 0;
 479}
 480EXPORT_SYMBOL_GPL(xt_compat_calc_jump);
 481
 482void xt_compat_init_offsets(u_int8_t af, unsigned int number)
 483{
 484        xt[af].number = number;
 485        xt[af].cur = 0;
 486}
 487EXPORT_SYMBOL(xt_compat_init_offsets);
 488
 489int xt_compat_match_offset(const struct xt_match *match)
 490{
 491        u_int16_t csize = match->compatsize ? : match->matchsize;
 492        return XT_ALIGN(match->matchsize) - COMPAT_XT_ALIGN(csize);
 493}
 494EXPORT_SYMBOL_GPL(xt_compat_match_offset);
 495
 496int xt_compat_match_from_user(struct xt_entry_match *m, void **dstptr,
 497                              unsigned int *size)
 498{
 499        const struct xt_match *match = m->u.kernel.match;
 500        struct compat_xt_entry_match *cm = (struct compat_xt_entry_match *)m;
 501        int pad, off = xt_compat_match_offset(match);
 502        u_int16_t msize = cm->u.user.match_size;
 503
 504        m = *dstptr;
 505        memcpy(m, cm, sizeof(*cm));
 506        if (match->compat_from_user)
 507                match->compat_from_user(m->data, cm->data);
 508        else
 509                memcpy(m->data, cm->data, msize - sizeof(*cm));
 510        pad = XT_ALIGN(match->matchsize) - match->matchsize;
 511        if (pad > 0)
 512                memset(m->data + match->matchsize, 0, pad);
 513
 514        msize += off;
 515        m->u.user.match_size = msize;
 516
 517        *size += off;
 518        *dstptr += msize;
 519        return 0;
 520}
 521EXPORT_SYMBOL_GPL(xt_compat_match_from_user);
 522
 523int xt_compat_match_to_user(const struct xt_entry_match *m,
 524                            void __user **dstptr, unsigned int *size)
 525{
 526        const struct xt_match *match = m->u.kernel.match;
 527        struct compat_xt_entry_match __user *cm = *dstptr;
 528        int off = xt_compat_match_offset(match);
 529        u_int16_t msize = m->u.user.match_size - off;
 530
 531        if (copy_to_user(cm, m, sizeof(*cm)) ||
 532            put_user(msize, &cm->u.user.match_size) ||
 533            copy_to_user(cm->u.user.name, m->u.kernel.match->name,
 534                         strlen(m->u.kernel.match->name) + 1))
 535                return -EFAULT;
 536
 537        if (match->compat_to_user) {
 538                if (match->compat_to_user((void __user *)cm->data, m->data))
 539                        return -EFAULT;
 540        } else {
 541                if (copy_to_user(cm->data, m->data, msize - sizeof(*cm)))
 542                        return -EFAULT;
 543        }
 544
 545        *size -= off;
 546        *dstptr += msize;
 547        return 0;
 548}
 549EXPORT_SYMBOL_GPL(xt_compat_match_to_user);
 550#endif /* CONFIG_COMPAT */
 551
 552int xt_check_target(struct xt_tgchk_param *par,
 553                    unsigned int size, u_int8_t proto, bool inv_proto)
 554{
 555        int ret;
 556
 557        if (XT_ALIGN(par->target->targetsize) != size) {
 558                pr_err("%s_tables: %s.%u target: invalid size "
 559                       "%u (kernel) != (user) %u\n",
 560                       xt_prefix[par->family], par->target->name,
 561                       par->target->revision,
 562                       XT_ALIGN(par->target->targetsize), size);
 563                return -EINVAL;
 564        }
 565        if (par->target->table != NULL &&
 566            strcmp(par->target->table, par->table) != 0) {
 567                pr_err("%s_tables: %s target: only valid in %s table, not %s\n",
 568                       xt_prefix[par->family], par->target->name,
 569                       par->target->table, par->table);
 570                return -EINVAL;
 571        }
 572        if (par->target->hooks && (par->hook_mask & ~par->target->hooks) != 0) {
 573                char used[64], allow[64];
 574
 575                pr_err("%s_tables: %s target: used from hooks %s, but only "
 576                       "usable from %s\n",
 577                       xt_prefix[par->family], par->target->name,
 578                       textify_hooks(used, sizeof(used), par->hook_mask),
 579                       textify_hooks(allow, sizeof(allow), par->target->hooks));
 580                return -EINVAL;
 581        }
 582        if (par->target->proto && (par->target->proto != proto || inv_proto)) {
 583                pr_err("%s_tables: %s target: only valid for protocol %u\n",
 584                       xt_prefix[par->family], par->target->name,
 585                       par->target->proto);
 586                return -EINVAL;
 587        }
 588        if (par->target->checkentry != NULL) {
 589                ret = par->target->checkentry(par);
 590                if (ret < 0)
 591                        return ret;
 592                else if (ret > 0)
 593                        /* Flag up potential errors. */
 594                        return -EIO;
 595        }
 596        return 0;
 597}
 598EXPORT_SYMBOL_GPL(xt_check_target);
 599
 600#ifdef CONFIG_COMPAT
 601int xt_compat_target_offset(const struct xt_target *target)
 602{
 603        u_int16_t csize = target->compatsize ? : target->targetsize;
 604        return XT_ALIGN(target->targetsize) - COMPAT_XT_ALIGN(csize);
 605}
 606EXPORT_SYMBOL_GPL(xt_compat_target_offset);
 607
 608void xt_compat_target_from_user(struct xt_entry_target *t, void **dstptr,
 609                                unsigned int *size)
 610{
 611        const struct xt_target *target = t->u.kernel.target;
 612        struct compat_xt_entry_target *ct = (struct compat_xt_entry_target *)t;
 613        int pad, off = xt_compat_target_offset(target);
 614        u_int16_t tsize = ct->u.user.target_size;
 615
 616        t = *dstptr;
 617        memcpy(t, ct, sizeof(*ct));
 618        if (target->compat_from_user)
 619                target->compat_from_user(t->data, ct->data);
 620        else
 621                memcpy(t->data, ct->data, tsize - sizeof(*ct));
 622        pad = XT_ALIGN(target->targetsize) - target->targetsize;
 623        if (pad > 0)
 624                memset(t->data + target->targetsize, 0, pad);
 625
 626        tsize += off;
 627        t->u.user.target_size = tsize;
 628
 629        *size += off;
 630        *dstptr += tsize;
 631}
 632EXPORT_SYMBOL_GPL(xt_compat_target_from_user);
 633
 634int xt_compat_target_to_user(const struct xt_entry_target *t,
 635                             void __user **dstptr, unsigned int *size)
 636{
 637        const struct xt_target *target = t->u.kernel.target;
 638        struct compat_xt_entry_target __user *ct = *dstptr;
 639        int off = xt_compat_target_offset(target);
 640        u_int16_t tsize = t->u.user.target_size - off;
 641
 642        if (copy_to_user(ct, t, sizeof(*ct)) ||
 643            put_user(tsize, &ct->u.user.target_size) ||
 644            copy_to_user(ct->u.user.name, t->u.kernel.target->name,
 645                         strlen(t->u.kernel.target->name) + 1))
 646                return -EFAULT;
 647
 648        if (target->compat_to_user) {
 649                if (target->compat_to_user((void __user *)ct->data, t->data))
 650                        return -EFAULT;
 651        } else {
 652                if (copy_to_user(ct->data, t->data, tsize - sizeof(*ct)))
 653                        return -EFAULT;
 654        }
 655
 656        *size -= off;
 657        *dstptr += tsize;
 658        return 0;
 659}
 660EXPORT_SYMBOL_GPL(xt_compat_target_to_user);
 661#endif
 662
 663struct xt_table_info *xt_alloc_table_info(unsigned int size)
 664{
 665        struct xt_table_info *newinfo;
 666        int cpu;
 667
 668        /* Pedantry: prevent them from hitting BUG() in vmalloc.c --RR */
 669        if ((SMP_ALIGN(size) >> PAGE_SHIFT) + 2 > totalram_pages)
 670                return NULL;
 671
 672        newinfo = kzalloc(XT_TABLE_INFO_SZ, GFP_KERNEL);
 673        if (!newinfo)
 674                return NULL;
 675
 676        newinfo->size = size;
 677
 678        for_each_possible_cpu(cpu) {
 679                if (size <= PAGE_SIZE)
 680                        newinfo->entries[cpu] = kmalloc_node(size,
 681                                                        GFP_KERNEL,
 682                                                        cpu_to_node(cpu));
 683                else
 684                        newinfo->entries[cpu] = vmalloc_node(size,
 685                                                        cpu_to_node(cpu));
 686
 687                if (newinfo->entries[cpu] == NULL) {
 688                        xt_free_table_info(newinfo);
 689                        return NULL;
 690                }
 691        }
 692
 693        return newinfo;
 694}
 695EXPORT_SYMBOL(xt_alloc_table_info);
 696
 697void xt_free_table_info(struct xt_table_info *info)
 698{
 699        int cpu;
 700
 701        for_each_possible_cpu(cpu) {
 702                if (info->size <= PAGE_SIZE)
 703                        kfree(info->entries[cpu]);
 704                else
 705                        vfree(info->entries[cpu]);
 706        }
 707
 708        if (info->jumpstack != NULL) {
 709                if (sizeof(void *) * info->stacksize > PAGE_SIZE) {
 710                        for_each_possible_cpu(cpu)
 711                                vfree(info->jumpstack[cpu]);
 712                } else {
 713                        for_each_possible_cpu(cpu)
 714                                kfree(info->jumpstack[cpu]);
 715                }
 716        }
 717
 718        if (sizeof(void **) * nr_cpu_ids > PAGE_SIZE)
 719                vfree(info->jumpstack);
 720        else
 721                kfree(info->jumpstack);
 722
 723        free_percpu(info->stackptr);
 724
 725        kfree(info);
 726}
 727EXPORT_SYMBOL(xt_free_table_info);
 728
 729/* Find table by name, grabs mutex & ref.  Returns ERR_PTR() on error. */
 730struct xt_table *xt_find_table_lock(struct net *net, u_int8_t af,
 731                                    const char *name)
 732{
 733        struct xt_table *t;
 734
 735        if (mutex_lock_interruptible(&xt[af].mutex) != 0)
 736                return ERR_PTR(-EINTR);
 737
 738        list_for_each_entry(t, &net->xt.tables[af], list)
 739                if (strcmp(t->name, name) == 0 && try_module_get(t->me))
 740                        return t;
 741        mutex_unlock(&xt[af].mutex);
 742        return NULL;
 743}
 744EXPORT_SYMBOL_GPL(xt_find_table_lock);
 745
 746void xt_table_unlock(struct xt_table *table)
 747{
 748        mutex_unlock(&xt[table->af].mutex);
 749}
 750EXPORT_SYMBOL_GPL(xt_table_unlock);
 751
 752#ifdef CONFIG_COMPAT
 753void xt_compat_lock(u_int8_t af)
 754{
 755        mutex_lock(&xt[af].compat_mutex);
 756}
 757EXPORT_SYMBOL_GPL(xt_compat_lock);
 758
 759void xt_compat_unlock(u_int8_t af)
 760{
 761        mutex_unlock(&xt[af].compat_mutex);
 762}
 763EXPORT_SYMBOL_GPL(xt_compat_unlock);
 764#endif
 765
 766DEFINE_PER_CPU(seqcount_t, xt_recseq);
 767EXPORT_PER_CPU_SYMBOL_GPL(xt_recseq);
 768
 769static int xt_jumpstack_alloc(struct xt_table_info *i)
 770{
 771        unsigned int size;
 772        int cpu;
 773
 774        i->stackptr = alloc_percpu(unsigned int);
 775        if (i->stackptr == NULL)
 776                return -ENOMEM;
 777
 778        size = sizeof(void **) * nr_cpu_ids;
 779        if (size > PAGE_SIZE)
 780                i->jumpstack = vzalloc(size);
 781        else
 782                i->jumpstack = kzalloc(size, GFP_KERNEL);
 783        if (i->jumpstack == NULL)
 784                return -ENOMEM;
 785
 786        i->stacksize *= xt_jumpstack_multiplier;
 787        size = sizeof(void *) * i->stacksize;
 788        for_each_possible_cpu(cpu) {
 789                if (size > PAGE_SIZE)
 790                        i->jumpstack[cpu] = vmalloc_node(size,
 791                                cpu_to_node(cpu));
 792                else
 793                        i->jumpstack[cpu] = kmalloc_node(size,
 794                                GFP_KERNEL, cpu_to_node(cpu));
 795                if (i->jumpstack[cpu] == NULL)
 796                        /*
 797                         * Freeing will be done later on by the callers. The
 798                         * chain is: xt_replace_table -> __do_replace ->
 799                         * do_replace -> xt_free_table_info.
 800                         */
 801                        return -ENOMEM;
 802        }
 803
 804        return 0;
 805}
 806
 807struct xt_table_info *
 808xt_replace_table(struct xt_table *table,
 809              unsigned int num_counters,
 810              struct xt_table_info *newinfo,
 811              int *error)
 812{
 813        struct xt_table_info *private;
 814        int ret;
 815
 816        ret = xt_jumpstack_alloc(newinfo);
 817        if (ret < 0) {
 818                *error = ret;
 819                return NULL;
 820        }
 821
 822        /* Do the substitution. */
 823        local_bh_disable();
 824        private = table->private;
 825
 826        /* Check inside lock: is the old number correct? */
 827        if (num_counters != private->number) {
 828                pr_debug("num_counters != table->private->number (%u/%u)\n",
 829                         num_counters, private->number);
 830                local_bh_enable();
 831                *error = -EAGAIN;
 832                return NULL;
 833        }
 834
 835        table->private = newinfo;
 836        newinfo->initial_entries = private->initial_entries;
 837
 838        /*
 839         * Even though table entries have now been swapped, other CPU's
 840         * may still be using the old entries. This is okay, because
 841         * resynchronization happens because of the locking done
 842         * during the get_counters() routine.
 843         */
 844        local_bh_enable();
 845
 846#ifdef CONFIG_AUDIT
 847        if (audit_enabled) {
 848                struct audit_buffer *ab;
 849
 850                ab = audit_log_start(current->audit_context, GFP_KERNEL,
 851                                     AUDIT_NETFILTER_CFG);
 852                if (ab) {
 853                        audit_log_format(ab, "table=%s family=%u entries=%u",
 854                                         table->name, table->af,
 855                                         private->number);
 856                        audit_log_end(ab);
 857                }
 858        }
 859#endif
 860
 861        return private;
 862}
 863EXPORT_SYMBOL_GPL(xt_replace_table);
 864
 865struct xt_table *xt_register_table(struct net *net,
 866                                   const struct xt_table *input_table,
 867                                   struct xt_table_info *bootstrap,
 868                                   struct xt_table_info *newinfo)
 869{
 870        int ret;
 871        struct xt_table_info *private;
 872        struct xt_table *t, *table;
 873
 874        /* Don't add one object to multiple lists. */
 875        table = kmemdup(input_table, sizeof(struct xt_table), GFP_KERNEL);
 876        if (!table) {
 877                ret = -ENOMEM;
 878                goto out;
 879        }
 880
 881        ret = mutex_lock_interruptible(&xt[table->af].mutex);
 882        if (ret != 0)
 883                goto out_free;
 884
 885        /* Don't autoload: we'd eat our tail... */
 886        list_for_each_entry(t, &net->xt.tables[table->af], list) {
 887                if (strcmp(t->name, table->name) == 0) {
 888                        ret = -EEXIST;
 889                        goto unlock;
 890                }
 891        }
 892
 893        /* Simplifies replace_table code. */
 894        table->private = bootstrap;
 895
 896        if (!xt_replace_table(table, 0, newinfo, &ret))
 897                goto unlock;
 898
 899        private = table->private;
 900        pr_debug("table->private->number = %u\n", private->number);
 901
 902        /* save number of initial entries */
 903        private->initial_entries = private->number;
 904
 905        list_add(&table->list, &net->xt.tables[table->af]);
 906        mutex_unlock(&xt[table->af].mutex);
 907        return table;
 908
 909 unlock:
 910        mutex_unlock(&xt[table->af].mutex);
 911out_free:
 912        kfree(table);
 913out:
 914        return ERR_PTR(ret);
 915}
 916EXPORT_SYMBOL_GPL(xt_register_table);
 917
 918void *xt_unregister_table(struct xt_table *table)
 919{
 920        struct xt_table_info *private;
 921
 922        mutex_lock(&xt[table->af].mutex);
 923        private = table->private;
 924        list_del(&table->list);
 925        mutex_unlock(&xt[table->af].mutex);
 926        kfree(table);
 927
 928        return private;
 929}
 930EXPORT_SYMBOL_GPL(xt_unregister_table);
 931
 932#ifdef CONFIG_PROC_FS
 933struct xt_names_priv {
 934        struct seq_net_private p;
 935        u_int8_t af;
 936};
 937static void *xt_table_seq_start(struct seq_file *seq, loff_t *pos)
 938{
 939        struct xt_names_priv *priv = seq->private;
 940        struct net *net = seq_file_net(seq);
 941        u_int8_t af = priv->af;
 942
 943        mutex_lock(&xt[af].mutex);
 944        return seq_list_start(&net->xt.tables[af], *pos);
 945}
 946
 947static void *xt_table_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 948{
 949        struct xt_names_priv *priv = seq->private;
 950        struct net *net = seq_file_net(seq);
 951        u_int8_t af = priv->af;
 952
 953        return seq_list_next(v, &net->xt.tables[af], pos);
 954}
 955
 956static void xt_table_seq_stop(struct seq_file *seq, void *v)
 957{
 958        struct xt_names_priv *priv = seq->private;
 959        u_int8_t af = priv->af;
 960
 961        mutex_unlock(&xt[af].mutex);
 962}
 963
 964static int xt_table_seq_show(struct seq_file *seq, void *v)
 965{
 966        struct xt_table *table = list_entry(v, struct xt_table, list);
 967
 968        if (strlen(table->name))
 969                return seq_printf(seq, "%s\n", table->name);
 970        else
 971                return 0;
 972}
 973
 974static const struct seq_operations xt_table_seq_ops = {
 975        .start  = xt_table_seq_start,
 976        .next   = xt_table_seq_next,
 977        .stop   = xt_table_seq_stop,
 978        .show   = xt_table_seq_show,
 979};
 980
 981static int xt_table_open(struct inode *inode, struct file *file)
 982{
 983        int ret;
 984        struct xt_names_priv *priv;
 985
 986        ret = seq_open_net(inode, file, &xt_table_seq_ops,
 987                           sizeof(struct xt_names_priv));
 988        if (!ret) {
 989                priv = ((struct seq_file *)file->private_data)->private;
 990                priv->af = (unsigned long)PDE(inode)->data;
 991        }
 992        return ret;
 993}
 994
 995static const struct file_operations xt_table_ops = {
 996        .owner   = THIS_MODULE,
 997        .open    = xt_table_open,
 998        .read    = seq_read,
 999        .llseek  = seq_lseek,
1000        .release = seq_release_net,
1001};
1002
1003/*
1004 * Traverse state for ip{,6}_{tables,matches} for helping crossing
1005 * the multi-AF mutexes.
1006 */
1007struct nf_mttg_trav {
1008        struct list_head *head, *curr;
1009        uint8_t class, nfproto;
1010};
1011
1012enum {
1013        MTTG_TRAV_INIT,
1014        MTTG_TRAV_NFP_UNSPEC,
1015        MTTG_TRAV_NFP_SPEC,
1016        MTTG_TRAV_DONE,
1017};
1018
1019static void *xt_mttg_seq_next(struct seq_file *seq, void *v, loff_t *ppos,
1020    bool is_target)
1021{
1022        static const uint8_t next_class[] = {
1023                [MTTG_TRAV_NFP_UNSPEC] = MTTG_TRAV_NFP_SPEC,
1024                [MTTG_TRAV_NFP_SPEC]   = MTTG_TRAV_DONE,
1025        };
1026        struct nf_mttg_trav *trav = seq->private;
1027
1028        switch (trav->class) {
1029        case MTTG_TRAV_INIT:
1030                trav->class = MTTG_TRAV_NFP_UNSPEC;
1031                mutex_lock(&xt[NFPROTO_UNSPEC].mutex);
1032                trav->head = trav->curr = is_target ?
1033                        &xt[NFPROTO_UNSPEC].target : &xt[NFPROTO_UNSPEC].match;
1034                break;
1035        case MTTG_TRAV_NFP_UNSPEC:
1036                trav->curr = trav->curr->next;
1037                if (trav->curr != trav->head)
1038                        break;
1039                mutex_unlock(&xt[NFPROTO_UNSPEC].mutex);
1040                mutex_lock(&xt[trav->nfproto].mutex);
1041                trav->head = trav->curr = is_target ?
1042                        &xt[trav->nfproto].target : &xt[trav->nfproto].match;
1043                trav->class = next_class[trav->class];
1044                break;
1045        case MTTG_TRAV_NFP_SPEC:
1046                trav->curr = trav->curr->next;
1047                if (trav->curr != trav->head)
1048                        break;
1049                /* fallthru, _stop will unlock */
1050        default:
1051                return NULL;
1052        }
1053
1054        if (ppos != NULL)
1055                ++*ppos;
1056        return trav;
1057}
1058
1059static void *xt_mttg_seq_start(struct seq_file *seq, loff_t *pos,
1060    bool is_target)
1061{
1062        struct nf_mttg_trav *trav = seq->private;
1063        unsigned int j;
1064
1065        trav->class = MTTG_TRAV_INIT;
1066        for (j = 0; j < *pos; ++j)
1067                if (xt_mttg_seq_next(seq, NULL, NULL, is_target) == NULL)
1068                        return NULL;
1069        return trav;
1070}
1071
1072static void xt_mttg_seq_stop(struct seq_file *seq, void *v)
1073{
1074        struct nf_mttg_trav *trav = seq->private;
1075
1076        switch (trav->class) {
1077        case MTTG_TRAV_NFP_UNSPEC:
1078                mutex_unlock(&xt[NFPROTO_UNSPEC].mutex);
1079                break;
1080        case MTTG_TRAV_NFP_SPEC:
1081                mutex_unlock(&xt[trav->nfproto].mutex);
1082                break;
1083        }
1084}
1085
1086static void *xt_match_seq_start(struct seq_file *seq, loff_t *pos)
1087{
1088        return xt_mttg_seq_start(seq, pos, false);
1089}
1090
1091static void *xt_match_seq_next(struct seq_file *seq, void *v, loff_t *ppos)
1092{
1093        return xt_mttg_seq_next(seq, v, ppos, false);
1094}
1095
1096static int xt_match_seq_show(struct seq_file *seq, void *v)
1097{
1098        const struct nf_mttg_trav *trav = seq->private;
1099        const struct xt_match *match;
1100
1101        switch (trav->class) {
1102        case MTTG_TRAV_NFP_UNSPEC:
1103        case MTTG_TRAV_NFP_SPEC:
1104                if (trav->curr == trav->head)
1105                        return 0;
1106                match = list_entry(trav->curr, struct xt_match, list);
1107                return (*match->name == '\0') ? 0 :
1108                       seq_printf(seq, "%s\n", match->name);
1109        }
1110        return 0;
1111}
1112
1113static const struct seq_operations xt_match_seq_ops = {
1114        .start  = xt_match_seq_start,
1115        .next   = xt_match_seq_next,
1116        .stop   = xt_mttg_seq_stop,
1117        .show   = xt_match_seq_show,
1118};
1119
1120static int xt_match_open(struct inode *inode, struct file *file)
1121{
1122        struct seq_file *seq;
1123        struct nf_mttg_trav *trav;
1124        int ret;
1125
1126        trav = kmalloc(sizeof(*trav), GFP_KERNEL);
1127        if (trav == NULL)
1128                return -ENOMEM;
1129
1130        ret = seq_open(file, &xt_match_seq_ops);
1131        if (ret < 0) {
1132                kfree(trav);
1133                return ret;
1134        }
1135
1136        seq = file->private_data;
1137        seq->private = trav;
1138        trav->nfproto = (unsigned long)PDE(inode)->data;
1139        return 0;
1140}
1141
1142static const struct file_operations xt_match_ops = {
1143        .owner   = THIS_MODULE,
1144        .open    = xt_match_open,
1145        .read    = seq_read,
1146        .llseek  = seq_lseek,
1147        .release = seq_release_private,
1148};
1149
1150static void *xt_target_seq_start(struct seq_file *seq, loff_t *pos)
1151{
1152        return xt_mttg_seq_start(seq, pos, true);
1153}
1154
1155static void *xt_target_seq_next(struct seq_file *seq, void *v, loff_t *ppos)
1156{
1157        return xt_mttg_seq_next(seq, v, ppos, true);
1158}
1159
1160static int xt_target_seq_show(struct seq_file *seq, void *v)
1161{
1162        const struct nf_mttg_trav *trav = seq->private;
1163        const struct xt_target *target;
1164
1165        switch (trav->class) {
1166        case MTTG_TRAV_NFP_UNSPEC:
1167        case MTTG_TRAV_NFP_SPEC:
1168                if (trav->curr == trav->head)
1169                        return 0;
1170                target = list_entry(trav->curr, struct xt_target, list);
1171                return (*target->name == '\0') ? 0 :
1172                       seq_printf(seq, "%s\n", target->name);
1173        }
1174        return 0;
1175}
1176
1177static const struct seq_operations xt_target_seq_ops = {
1178        .start  = xt_target_seq_start,
1179        .next   = xt_target_seq_next,
1180        .stop   = xt_mttg_seq_stop,
1181        .show   = xt_target_seq_show,
1182};
1183
1184static int xt_target_open(struct inode *inode, struct file *file)
1185{
1186        struct seq_file *seq;
1187        struct nf_mttg_trav *trav;
1188        int ret;
1189
1190        trav = kmalloc(sizeof(*trav), GFP_KERNEL);
1191        if (trav == NULL)
1192                return -ENOMEM;
1193
1194        ret = seq_open(file, &xt_target_seq_ops);
1195        if (ret < 0) {
1196                kfree(trav);
1197                return ret;
1198        }
1199
1200        seq = file->private_data;
1201        seq->private = trav;
1202        trav->nfproto = (unsigned long)PDE(inode)->data;
1203        return 0;
1204}
1205
1206static const struct file_operations xt_target_ops = {
1207        .owner   = THIS_MODULE,
1208        .open    = xt_target_open,
1209        .read    = seq_read,
1210        .llseek  = seq_lseek,
1211        .release = seq_release_private,
1212};
1213
1214#define FORMAT_TABLES   "_tables_names"
1215#define FORMAT_MATCHES  "_tables_matches"
1216#define FORMAT_TARGETS  "_tables_targets"
1217
1218#endif /* CONFIG_PROC_FS */
1219
1220/**
1221 * xt_hook_link - set up hooks for a new table
1222 * @table:      table with metadata needed to set up hooks
1223 * @fn:         Hook function
1224 *
1225 * This function will take care of creating and registering the necessary
1226 * Netfilter hooks for XT tables.
1227 */
1228struct nf_hook_ops *xt_hook_link(const struct xt_table *table, nf_hookfn *fn)
1229{
1230        unsigned int hook_mask = table->valid_hooks;
1231        uint8_t i, num_hooks = hweight32(hook_mask);
1232        uint8_t hooknum;
1233        struct nf_hook_ops *ops;
1234        int ret;
1235
1236        ops = kmalloc(sizeof(*ops) * num_hooks, GFP_KERNEL);
1237        if (ops == NULL)
1238                return ERR_PTR(-ENOMEM);
1239
1240        for (i = 0, hooknum = 0; i < num_hooks && hook_mask != 0;
1241             hook_mask >>= 1, ++hooknum) {
1242                if (!(hook_mask & 1))
1243                        continue;
1244                ops[i].hook     = fn;
1245                ops[i].owner    = table->me;
1246                ops[i].pf       = table->af;
1247                ops[i].hooknum  = hooknum;
1248                ops[i].priority = table->priority;
1249                ++i;
1250        }
1251
1252        ret = nf_register_hooks(ops, num_hooks);
1253        if (ret < 0) {
1254                kfree(ops);
1255                return ERR_PTR(ret);
1256        }
1257
1258        return ops;
1259}
1260EXPORT_SYMBOL_GPL(xt_hook_link);
1261
1262/**
1263 * xt_hook_unlink - remove hooks for a table
1264 * @ops:        nf_hook_ops array as returned by nf_hook_link
1265 * @hook_mask:  the very same mask that was passed to nf_hook_link
1266 */
1267void xt_hook_unlink(const struct xt_table *table, struct nf_hook_ops *ops)
1268{
1269        nf_unregister_hooks(ops, hweight32(table->valid_hooks));
1270        kfree(ops);
1271}
1272EXPORT_SYMBOL_GPL(xt_hook_unlink);
1273
1274int xt_proto_init(struct net *net, u_int8_t af)
1275{
1276#ifdef CONFIG_PROC_FS
1277        char buf[XT_FUNCTION_MAXNAMELEN];
1278        struct proc_dir_entry *proc;
1279#endif
1280
1281        if (af >= ARRAY_SIZE(xt_prefix))
1282                return -EINVAL;
1283
1284
1285#ifdef CONFIG_PROC_FS
1286        strlcpy(buf, xt_prefix[af], sizeof(buf));
1287        strlcat(buf, FORMAT_TABLES, sizeof(buf));
1288        proc = proc_create_data(buf, 0440, net->proc_net, &xt_table_ops,
1289                                (void *)(unsigned long)af);
1290        if (!proc)
1291                goto out;
1292
1293        strlcpy(buf, xt_prefix[af], sizeof(buf));
1294        strlcat(buf, FORMAT_MATCHES, sizeof(buf));
1295        proc = proc_create_data(buf, 0440, net->proc_net, &xt_match_ops,
1296                                (void *)(unsigned long)af);
1297        if (!proc)
1298                goto out_remove_tables;
1299
1300        strlcpy(buf, xt_prefix[af], sizeof(buf));
1301        strlcat(buf, FORMAT_TARGETS, sizeof(buf));
1302        proc = proc_create_data(buf, 0440, net->proc_net, &xt_target_ops,
1303                                (void *)(unsigned long)af);
1304        if (!proc)
1305                goto out_remove_matches;
1306#endif
1307
1308        return 0;
1309
1310#ifdef CONFIG_PROC_FS
1311out_remove_matches:
1312        strlcpy(buf, xt_prefix[af], sizeof(buf));
1313        strlcat(buf, FORMAT_MATCHES, sizeof(buf));
1314        proc_net_remove(net, buf);
1315
1316out_remove_tables:
1317        strlcpy(buf, xt_prefix[af], sizeof(buf));
1318        strlcat(buf, FORMAT_TABLES, sizeof(buf));
1319        proc_net_remove(net, buf);
1320out:
1321        return -1;
1322#endif
1323}
1324EXPORT_SYMBOL_GPL(xt_proto_init);
1325
1326void xt_proto_fini(struct net *net, u_int8_t af)
1327{
1328#ifdef CONFIG_PROC_FS
1329        char buf[XT_FUNCTION_MAXNAMELEN];
1330
1331        strlcpy(buf, xt_prefix[af], sizeof(buf));
1332        strlcat(buf, FORMAT_TABLES, sizeof(buf));
1333        proc_net_remove(net, buf);
1334
1335        strlcpy(buf, xt_prefix[af], sizeof(buf));
1336        strlcat(buf, FORMAT_TARGETS, sizeof(buf));
1337        proc_net_remove(net, buf);
1338
1339        strlcpy(buf, xt_prefix[af], sizeof(buf));
1340        strlcat(buf, FORMAT_MATCHES, sizeof(buf));
1341        proc_net_remove(net, buf);
1342#endif /*CONFIG_PROC_FS*/
1343}
1344EXPORT_SYMBOL_GPL(xt_proto_fini);
1345
1346static int __net_init xt_net_init(struct net *net)
1347{
1348        int i;
1349
1350        for (i = 0; i < NFPROTO_NUMPROTO; i++)
1351                INIT_LIST_HEAD(&net->xt.tables[i]);
1352        return 0;
1353}
1354
1355static struct pernet_operations xt_net_ops = {
1356        .init = xt_net_init,
1357};
1358
1359static int __init xt_init(void)
1360{
1361        unsigned int i;
1362        int rv;
1363
1364        for_each_possible_cpu(i) {
1365                seqcount_init(&per_cpu(xt_recseq, i));
1366        }
1367
1368        xt = kmalloc(sizeof(struct xt_af) * NFPROTO_NUMPROTO, GFP_KERNEL);
1369        if (!xt)
1370                return -ENOMEM;
1371
1372        for (i = 0; i < NFPROTO_NUMPROTO; i++) {
1373                mutex_init(&xt[i].mutex);
1374#ifdef CONFIG_COMPAT
1375                mutex_init(&xt[i].compat_mutex);
1376                xt[i].compat_tab = NULL;
1377#endif
1378                INIT_LIST_HEAD(&xt[i].target);
1379                INIT_LIST_HEAD(&xt[i].match);
1380        }
1381        rv = register_pernet_subsys(&xt_net_ops);
1382        if (rv < 0)
1383                kfree(xt);
1384        return rv;
1385}
1386
1387static void __exit xt_fini(void)
1388{
1389        unregister_pernet_subsys(&xt_net_ops);
1390        kfree(xt);
1391}
1392
1393module_init(xt_init);
1394module_exit(xt_fini);
1395
1396
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