net/netfilter/x_tables.c

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