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 int xt_check_match(struct xt_mtchk_param *par,
 333                    unsigned int size, u_int8_t proto, bool inv_proto)
 334 {
 335         if (XT_ALIGN(par->match->matchsize) != size &&
 336             par->match->matchsize != -1) {
 337                 /*
 338                  * ebt_among is exempt from centralized matchsize checking
 339                  * because it uses a dynamic-size data set.
 340                  */
 341                 printk("%s_tables: %s match: invalid size %Zu != %u\n",
 342                        xt_prefix[par->family], par->match->name,
 343                        XT_ALIGN(par->match->matchsize), size);
 344                 return -EINVAL;
 345         }
 346         if (par->match->table != NULL &&
 347             strcmp(par->match->table, par->table) != 0) {
 348                 printk("%s_tables: %s match: only valid in %s table, not %s\n",
 349                        xt_prefix[par->family], par->match->name,
 350                        par->match->table, par->table);
 351                 return -EINVAL;
 352         }
 353         if (par->match->hooks && (par->hook_mask & ~par->match->hooks) != 0) {
 354                 printk("%s_tables: %s match: bad hook_mask %#x/%#x\n",
 355                        xt_prefix[par->family], par->match->name,
 356                        par->hook_mask, par->match->hooks);
 357                 return -EINVAL;
 358         }
 359         if (par->match->proto && (par->match->proto != proto || inv_proto)) {
 360                 printk("%s_tables: %s match: only valid for protocol %u\n",
 361                        xt_prefix[par->family], par->match->name,
 362                        par->match->proto);
 363                 return -EINVAL;
 364         }
 365         if (par->match->checkentry != NULL && !par->match->checkentry(par))
 366                 return -EINVAL;
 367         return 0;
 368 }
 369 EXPORT_SYMBOL_GPL(xt_check_match);
 370
 371 #ifdef CONFIG_COMPAT
 372 int xt_compat_add_offset(u_int8_t af, unsigned int offset, short delta)
 373 {
 374         struct compat_delta *tmp;
 375
 376         tmp = kmalloc(sizeof(struct compat_delta), GFP_KERNEL);
 377         if (!tmp)
 378                 return -ENOMEM;
 379
 380         tmp->offset = offset;
 381         tmp->delta = delta;
 382
 383         if (xt[af].compat_offsets) {
 384                 tmp->next = xt[af].compat_offsets->next;
 385                 xt[af].compat_offsets->next = tmp;
 386         } else {
 387                 xt[af].compat_offsets = tmp;
 388                 tmp->next = NULL;
 389         }
 390         return 0;
 391 }
 392 EXPORT_SYMBOL_GPL(xt_compat_add_offset);
 393
 394 void xt_compat_flush_offsets(u_int8_t af)
 395 {
 396         struct compat_delta *tmp, *next;
 397
 398         if (xt[af].compat_offsets) {
 399                 for (tmp = xt[af].compat_offsets; tmp; tmp = next) {
 400                         next = tmp->next;
 401                         kfree(tmp);
 402                 }
 403                 xt[af].compat_offsets = NULL;
 404         }
 405 }
 406 EXPORT_SYMBOL_GPL(xt_compat_flush_offsets);
 407
 408 short xt_compat_calc_jump(u_int8_t af, unsigned int offset)
 409 {
 410         struct compat_delta *tmp;
 411         short delta;
 412
 413         for (tmp = xt[af].compat_offsets, delta = 0; tmp; tmp = tmp->next)
 414                 if (tmp->offset < offset)
 415                         delta += tmp->delta;
 416         return delta;
 417 }
 418 EXPORT_SYMBOL_GPL(xt_compat_calc_jump);
 419
 420 int xt_compat_match_offset(const struct xt_match *match)
 421 {
 422         u_int16_t csize = match->compatsize ? : match->matchsize;
 423         return XT_ALIGN(match->matchsize) - COMPAT_XT_ALIGN(csize);
 424 }
 425 EXPORT_SYMBOL_GPL(xt_compat_match_offset);
 426
 427 int xt_compat_match_from_user(struct xt_entry_match *m, void **dstptr,
 428                               unsigned int *size)
 429 {
 430         const struct xt_match *match = m->u.kernel.match;
 431         struct compat_xt_entry_match *cm = (struct compat_xt_entry_match *)m;
 432         int pad, off = xt_compat_match_offset(match);
 433         u_int16_t msize = cm->u.user.match_size;
 434
 435         m = *dstptr;
 436         memcpy(m, cm, sizeof(*cm));
 437         if (match->compat_from_user)
 438                 match->compat_from_user(m->data, cm->data);
 439         else
 440                 memcpy(m->data, cm->data, msize - sizeof(*cm));
 441         pad = XT_ALIGN(match->matchsize) - match->matchsize;
 442         if (pad > 0)
 443                 memset(m->data + match->matchsize, 0, pad);
 444
 445         msize += off;
 446         m->u.user.match_size = msize;
 447
 448         *size += off;
 449         *dstptr += msize;
 450         return 0;
 451 }
 452 EXPORT_SYMBOL_GPL(xt_compat_match_from_user);
 453
 454 int xt_compat_match_to_user(struct xt_entry_match *m, void __user **dstptr,
 455                             unsigned int *size)
 456 {
 457         const struct xt_match *match = m->u.kernel.match;
 458         struct compat_xt_entry_match __user *cm = *dstptr;
 459         int off = xt_compat_match_offset(match);
 460         u_int16_t msize = m->u.user.match_size - off;
 461
 462         if (copy_to_user(cm, m, sizeof(*cm)) ||
 463             put_user(msize, &cm->u.user.match_size) ||
 464             copy_to_user(cm->u.user.name, m->u.kernel.match->name,
 465                          strlen(m->u.kernel.match->name) + 1))
 466                 return -EFAULT;
 467
 468         if (match->compat_to_user) {
 469                 if (match->compat_to_user((void __user *)cm->data, m->data))
 470                         return -EFAULT;
 471         } else {
 472                 if (copy_to_user(cm->data, m->data, msize - sizeof(*cm)))
 473                         return -EFAULT;
 474         }
 475
 476         *size -= off;
 477         *dstptr += msize;
 478         return 0;
 479 }
 480 EXPORT_SYMBOL_GPL(xt_compat_match_to_user);
 481 #endif /* CONFIG_COMPAT */
 482
 483 int xt_check_target(struct xt_tgchk_param *par,
 484                     unsigned int size, u_int8_t proto, bool inv_proto)
 485 {
 486         if (XT_ALIGN(par->target->targetsize) != size) {
 487                 printk("%s_tables: %s target: invalid size %Zu != %u\n",
 488                        xt_prefix[par->family], par->target->name,
 489                        XT_ALIGN(par->target->targetsize), size);
 490                 return -EINVAL;
 491         }
 492         if (par->target->table != NULL &&
 493             strcmp(par->target->table, par->table) != 0) {
 494                 printk("%s_tables: %s target: only valid in %s table, not %s\n",
 495                        xt_prefix[par->family], par->target->name,
 496                        par->target->table, par->table);
 497                 return -EINVAL;
 498         }
 499         if (par->target->hooks && (par->hook_mask & ~par->target->hooks) != 0) {
 500                 printk("%s_tables: %s target: bad hook_mask %#x/%#x\n",
 501                        xt_prefix[par->family], par->target->name,
 502                        par->hook_mask, par->target->hooks);
 503                 return -EINVAL;
 504         }
 505         if (par->target->proto && (par->target->proto != proto || inv_proto)) {
 506                 printk("%s_tables: %s target: only valid for protocol %u\n",
 507                        xt_prefix[par->family], par->target->name,
 508                        par->target->proto);
 509                 return -EINVAL;
 510         }
 511         if (par->target->checkentry != NULL && !par->target->checkentry(par))
 512                 return -EINVAL;
 513         return 0;
 514 }
 515 EXPORT_SYMBOL_GPL(xt_check_target);
 516
 517 #ifdef CONFIG_COMPAT
 518 int xt_compat_target_offset(const struct xt_target *target)
 519 {
 520         u_int16_t csize = target->compatsize ? : target->targetsize;
 521         return XT_ALIGN(target->targetsize) - COMPAT_XT_ALIGN(csize);
 522 }
 523 EXPORT_SYMBOL_GPL(xt_compat_target_offset);
 524
 525 void xt_compat_target_from_user(struct xt_entry_target *t, void **dstptr,
 526                                 unsigned int *size)
 527 {
 528         const struct xt_target *target = t->u.kernel.target;
 529         struct compat_xt_entry_target *ct = (struct compat_xt_entry_target *)t;
 530         int pad, off = xt_compat_target_offset(target);
 531         u_int16_t tsize = ct->u.user.target_size;
 532
 533         t = *dstptr;
 534         memcpy(t, ct, sizeof(*ct));
 535         if (target->compat_from_user)
 536                 target->compat_from_user(t->data, ct->data);
 537         else
 538                 memcpy(t->data, ct->data, tsize - sizeof(*ct));
 539         pad = XT_ALIGN(target->targetsize) - target->targetsize;
 540         if (pad > 0)
 541                 memset(t->data + target->targetsize, 0, pad);
 542
 543         tsize += off;
 544         t->u.user.target_size = tsize;
 545
 546         *size += off;
 547         *dstptr += tsize;
 548 }
 549 EXPORT_SYMBOL_GPL(xt_compat_target_from_user);
 550
 551 int xt_compat_target_to_user(struct xt_entry_target *t, void __user **dstptr,
 552                              unsigned int *size)
 553 {
 554         const struct xt_target *target = t->u.kernel.target;
 555         struct compat_xt_entry_target __user *ct = *dstptr;
 556         int off = xt_compat_target_offset(target);
 557         u_int16_t tsize = t->u.user.target_size - off;
 558
 559         if (copy_to_user(ct, t, sizeof(*ct)) ||
 560             put_user(tsize, &ct->u.user.target_size) ||
 561             copy_to_user(ct->u.user.name, t->u.kernel.target->name,
 562                          strlen(t->u.kernel.target->name) + 1))
 563                 return -EFAULT;
 564
 565         if (target->compat_to_user) {
 566                 if (target->compat_to_user((void __user *)ct->data, t->data))
 567                         return -EFAULT;
 568         } else {
 569                 if (copy_to_user(ct->data, t->data, tsize - sizeof(*ct)))
 570                         return -EFAULT;
 571         }
 572
 573         *size -= off;
 574         *dstptr += tsize;
 575         return 0;
 576 }
 577 EXPORT_SYMBOL_GPL(xt_compat_target_to_user);
 578 #endif
 579
 580 struct xt_table_info *xt_alloc_table_info(unsigned int size)
 581 {
 582         struct xt_table_info *newinfo;
 583         int cpu;
 584
 585         /* Pedantry: prevent them from hitting BUG() in vmalloc.c --RR */
 586         if ((SMP_ALIGN(size) >> PAGE_SHIFT) + 2 > num_physpages)
 587                 return NULL;
 588
 589         newinfo = kzalloc(XT_TABLE_INFO_SZ, GFP_KERNEL);
 590         if (!newinfo)
 591                 return NULL;
 592
 593         newinfo->size = size;
 594
 595         for_each_possible_cpu(cpu) {
 596                 if (size <= PAGE_SIZE)
 597                         newinfo->entries[cpu] = kmalloc_node(size,
 598                                                         GFP_KERNEL,
 599                                                         cpu_to_node(cpu));
 600                 else
 601                         newinfo->entries[cpu] = vmalloc_node(size,
 602                                                         cpu_to_node(cpu));
 603
 604                 if (newinfo->entries[cpu] == NULL) {
 605                         xt_free_table_info(newinfo);
 606                         return NULL;
 607                 }
 608         }
 609
 610         return newinfo;
 611 }
 612 EXPORT_SYMBOL(xt_alloc_table_info);
 613
 614 void xt_free_table_info(struct xt_table_info *info)
 615 {
 616         int cpu;
 617
 618         for_each_possible_cpu(cpu) {
 619                 if (info->size <= PAGE_SIZE)
 620                         kfree(info->entries[cpu]);
 621                 else
 622                         vfree(info->entries[cpu]);
 623         }
 624         kfree(info);
 625 }
 626 EXPORT_SYMBOL(xt_free_table_info);
 627
 628 /* Find table by name, grabs mutex & ref.  Returns ERR_PTR() on error. */
 629 struct xt_table *xt_find_table_lock(struct net *net, u_int8_t af,
 630                                     const char *name)
 631 {
 632         struct xt_table *t;
 633
 634         if (mutex_lock_interruptible(&xt[af].mutex) != 0)
 635                 return ERR_PTR(-EINTR);
 636
 637         list_for_each_entry(t, &net->xt.tables[af], list)
 638                 if (strcmp(t->name, name) == 0 && try_module_get(t->me))
 639                         return t;
 640         mutex_unlock(&xt[af].mutex);
 641         return NULL;
 642 }
 643 EXPORT_SYMBOL_GPL(xt_find_table_lock);
 644
 645 void xt_table_unlock(struct xt_table *table)
 646 {
 647         mutex_unlock(&xt[table->af].mutex);
 648 }
 649 EXPORT_SYMBOL_GPL(xt_table_unlock);
 650
 651 #ifdef CONFIG_COMPAT
 652 void xt_compat_lock(u_int8_t af)
 653 {
 654         mutex_lock(&xt[af].compat_mutex);
 655 }
 656 EXPORT_SYMBOL_GPL(xt_compat_lock);
 657
 658 void xt_compat_unlock(u_int8_t af)
 659 {
 660         mutex_unlock(&xt[af].compat_mutex);
 661 }
 662 EXPORT_SYMBOL_GPL(xt_compat_unlock);
 663 #endif
 664
 665 DEFINE_PER_CPU(struct xt_info_lock, xt_info_locks);
 666 EXPORT_PER_CPU_SYMBOL_GPL(xt_info_locks);
 667
 668
 669 struct xt_table_info *
 670 xt_replace_table(struct xt_table *table,
 671               unsigned int num_counters,
 672               struct xt_table_info *newinfo,
 673               int *error)
 674 {
 675         struct xt_table_info *private;
 676
 677         /* Do the substitution. */
 678         local_bh_disable();
 679         private = table->private;
 680
 681         /* Check inside lock: is the old number correct? */
 682         if (num_counters != private->number) {
 683                 duprintf("num_counters != table->private->number (%u/%u)\n",
 684                          num_counters, private->number);
 685                 local_bh_enable();
 686                 *error = -EAGAIN;
 687                 return NULL;
 688         }
 689
 690         table->private = newinfo;
 691         newinfo->initial_entries = private->initial_entries;
 692
 693         /*
 694          * Even though table entries have now been swapped, other CPU's
 695          * may still be using the old entries. This is okay, because
 696          * resynchronization happens because of the locking done
 697          * during the get_counters() routine.
 698          */
 699         local_bh_enable();
 700
 701         return private;
 702 }
 703 EXPORT_SYMBOL_GPL(xt_replace_table);
 704
 705 struct xt_table *xt_register_table(struct net *net, struct xt_table *table,
 706                                    struct xt_table_info *bootstrap,
 707                                    struct xt_table_info *newinfo)
 708 {
 709         int ret;
 710         struct xt_table_info *private;
 711         struct xt_table *t;
 712
 713         /* Don't add one object to multiple lists. */
 714         table = kmemdup(table, sizeof(struct xt_table), GFP_KERNEL);
 715         if (!table) {
 716                 ret = -ENOMEM;
 717                 goto out;
 718         }
 719
 720         ret = mutex_lock_interruptible(&xt[table->af].mutex);
 721         if (ret != 0)
 722                 goto out_free;
 723
 724         /* Don't autoload: we'd eat our tail... */
 725         list_for_each_entry(t, &net->xt.tables[table->af], list) {
 726                 if (strcmp(t->name, table->name) == 0) {
 727                         ret = -EEXIST;
 728                         goto unlock;
 729                 }
 730         }
 731
 732         /* Simplifies replace_table code. */
 733         table->private = bootstrap;
 734
 735         if (!xt_replace_table(table, 0, newinfo, &ret))
 736                 goto unlock;
 737
 738         private = table->private;
 739         duprintf("table->private->number = %u\n", private->number);
 740
 741         /* save number of initial entries */
 742         private->initial_entries = private->number;
 743
 744         list_add(&table->list, &net->xt.tables[table->af]);
 745         mutex_unlock(&xt[table->af].mutex);
 746         return table;
 747
 748  unlock:
 749         mutex_unlock(&xt[table->af].mutex);
 750 out_free:
 751         kfree(table);
 752 out:
 753         return ERR_PTR(ret);
 754 }
 755 EXPORT_SYMBOL_GPL(xt_register_table);
 756
 757 void *xt_unregister_table(struct xt_table *table)
 758 {
 759         struct xt_table_info *private;
 760
 761         mutex_lock(&xt[table->af].mutex);
 762         private = table->private;
 763         list_del(&table->list);
 764         mutex_unlock(&xt[table->af].mutex);
 765         kfree(table);
 766
 767         return private;
 768 }
 769 EXPORT_SYMBOL_GPL(xt_unregister_table);
 770
 771 #ifdef CONFIG_PROC_FS
 772 struct xt_names_priv {
 773         struct seq_net_private p;
 774         u_int8_t af;
 775 };
 776 static void *xt_table_seq_start(struct seq_file *seq, loff_t *pos)
 777 {
 778         struct xt_names_priv *priv = seq->private;
 779         struct net *net = seq_file_net(seq);
 780         u_int8_t af = priv->af;
 781
 782         mutex_lock(&xt[af].mutex);
 783         return seq_list_start(&net->xt.tables[af], *pos);
 784 }
 785
 786 static void *xt_table_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 787 {
 788         struct xt_names_priv *priv = seq->private;
 789         struct net *net = seq_file_net(seq);
 790         u_int8_t af = priv->af;
 791
 792         return seq_list_next(v, &net->xt.tables[af], pos);
 793 }
 794
 795 static void xt_table_seq_stop(struct seq_file *seq, void *v)
 796 {
 797         struct xt_names_priv *priv = seq->private;
 798         u_int8_t af = priv->af;
 799
 800         mutex_unlock(&xt[af].mutex);
 801 }
 802
 803 static int xt_table_seq_show(struct seq_file *seq, void *v)
 804 {
 805         struct xt_table *table = list_entry(v, struct xt_table, list);
 806
 807         if (strlen(table->name))
 808                 return seq_printf(seq, "%s\n", table->name);
 809         else
 810                 return 0;
 811 }
 812
 813 static const struct seq_operations xt_table_seq_ops = {
 814         .start  = xt_table_seq_start,
 815         .next   = xt_table_seq_next,
 816         .stop   = xt_table_seq_stop,
 817         .show   = xt_table_seq_show,
 818 };
 819
 820 static int xt_table_open(struct inode *inode, struct file *file)
 821 {
 822         int ret;
 823         struct xt_names_priv *priv;
 824
 825         ret = seq_open_net(inode, file, &xt_table_seq_ops,
 826                            sizeof(struct xt_names_priv));
 827         if (!ret) {
 828                 priv = ((struct seq_file *)file->private_data)->private;
 829                 priv->af = (unsigned long)PDE(inode)->data;
 830         }
 831         return ret;
 832 }
 833
 834 static const struct file_operations xt_table_ops = {
 835         .owner   = THIS_MODULE,
 836         .open    = xt_table_open,
 837         .read    = seq_read,
 838         .llseek  = seq_lseek,
 839         .release = seq_release_net,
 840 };
 841
 842 /*
 843  * Traverse state for ip{,6}_{tables,matches} for helping crossing
 844  * the multi-AF mutexes.
 845  */
 846 struct nf_mttg_trav {
 847         struct list_head *head, *curr;
 848         uint8_t class, nfproto;
 849 };
 850
 851 enum {
 852         MTTG_TRAV_INIT,
 853         MTTG_TRAV_NFP_UNSPEC,
 854         MTTG_TRAV_NFP_SPEC,
 855         MTTG_TRAV_DONE,
 856 };
 857
 858 static void *xt_mttg_seq_next(struct seq_file *seq, void *v, loff_t *ppos,
 859     bool is_target)
 860 {
 861         static const uint8_t next_class[] = {
 862                 [MTTG_TRAV_NFP_UNSPEC] = MTTG_TRAV_NFP_SPEC,
 863                 [MTTG_TRAV_NFP_SPEC]   = MTTG_TRAV_DONE,
 864         };
 865         struct nf_mttg_trav *trav = seq->private;
 866
 867         switch (trav->class) {
 868         case MTTG_TRAV_INIT:
 869                 trav->class = MTTG_TRAV_NFP_UNSPEC;
 870                 mutex_lock(&xt[NFPROTO_UNSPEC].mutex);
 871                 trav->head = trav->curr = is_target ?
 872                         &xt[NFPROTO_UNSPEC].target : &xt[NFPROTO_UNSPEC].match;
 873                 break;
 874         case MTTG_TRAV_NFP_UNSPEC:
 875                 trav->curr = trav->curr->next;
 876                 if (trav->curr != trav->head)
 877                         break;
 878                 mutex_unlock(&xt[NFPROTO_UNSPEC].mutex);
 879                 mutex_lock(&xt[trav->nfproto].mutex);
 880                 trav->head = trav->curr = is_target ?
 881                         &xt[trav->nfproto].target : &xt[trav->nfproto].match;
 882                 trav->class = next_class[trav->class];
 883                 break;
 884         case MTTG_TRAV_NFP_SPEC:
 885                 trav->curr = trav->curr->next;
 886                 if (trav->curr != trav->head)
 887                         break;
 888                 /* fallthru, _stop will unlock */
 889         default:
 890                 return NULL;
 891         }
 892
 893         if (ppos != NULL)
 894                 ++*ppos;
 895         return trav;
 896 }
 897
 898 static void *xt_mttg_seq_start(struct seq_file *seq, loff_t *pos,
 899     bool is_target)
 900 {
 901         struct nf_mttg_trav *trav = seq->private;
 902         unsigned int j;
 903
 904         trav->class = MTTG_TRAV_INIT;
 905         for (j = 0; j < *pos; ++j)
 906                 if (xt_mttg_seq_next(seq, NULL, NULL, is_target) == NULL)
 907                         return NULL;
 908         return trav;
 909 }
 910
 911 static void xt_mttg_seq_stop(struct seq_file *seq, void *v)
 912 {
 913         struct nf_mttg_trav *trav = seq->private;
 914
 915         switch (trav->class) {
 916         case MTTG_TRAV_NFP_UNSPEC:
 917                 mutex_unlock(&xt[NFPROTO_UNSPEC].mutex);
 918                 break;
 919         case MTTG_TRAV_NFP_SPEC:
 920                 mutex_unlock(&xt[trav->nfproto].mutex);
 921                 break;
 922         }
 923 }
 924
 925 static void *xt_match_seq_start(struct seq_file *seq, loff_t *pos)
 926 {
 927         return xt_mttg_seq_start(seq, pos, false);
 928 }
 929
 930 static void *xt_match_seq_next(struct seq_file *seq, void *v, loff_t *ppos)
 931 {
 932         return xt_mttg_seq_next(seq, v, ppos, false);
 933 }
 934
 935 static int xt_match_seq_show(struct seq_file *seq, void *v)
 936 {
 937         const struct nf_mttg_trav *trav = seq->private;
 938         const struct xt_match *match;
 939
 940         switch (trav->class) {
 941         case MTTG_TRAV_NFP_UNSPEC:
 942         case MTTG_TRAV_NFP_SPEC:
 943                 if (trav->curr == trav->head)
 944                         return 0;
 945                 match = list_entry(trav->curr, struct xt_match, list);
 946                 return (*match->name == '\0') ? 0 :
 947                        seq_printf(seq, "%s\n", match->name);
 948         }
 949         return 0;
 950 }
 951
 952 static const struct seq_operations xt_match_seq_ops = {
 953         .start  = xt_match_seq_start,
 954         .next   = xt_match_seq_next,
 955         .stop   = xt_mttg_seq_stop,
 956         .show   = xt_match_seq_show,
 957 };
 958
 959 static int xt_match_open(struct inode *inode, struct file *file)
 960 {
 961         struct seq_file *seq;
 962         struct nf_mttg_trav *trav;
 963         int ret;
 964
 965         trav = kmalloc(sizeof(*trav), GFP_KERNEL);
 966         if (trav == NULL)
 967                 return -ENOMEM;
 968
 969         ret = seq_open(file, &xt_match_seq_ops);
 970         if (ret < 0) {
 971                 kfree(trav);
 972                 return ret;
 973         }
 974
 975         seq = file->private_data;
 976         seq->private = trav;
 977         trav->nfproto = (unsigned long)PDE(inode)->data;
 978         return 0;
 979 }
 980
 981 static const struct file_operations xt_match_ops = {
 982         .owner   = THIS_MODULE,
 983         .open    = xt_match_open,
 984         .read    = seq_read,
 985         .llseek  = seq_lseek,
 986         .release = seq_release_private,
 987 };
 988
 989 static void *xt_target_seq_start(struct seq_file *seq, loff_t *pos)
 990 {
 991         return xt_mttg_seq_start(seq, pos, true);
 992 }
 993
 994 static void *xt_target_seq_next(struct seq_file *seq, void *v, loff_t *ppos)
 995 {
 996         return xt_mttg_seq_next(seq, v, ppos, true);
 997 }
 998
 999 static int xt_target_seq_show(struct seq_file *seq, void *v)
1000 {
1001         const struct nf_mttg_trav *trav = seq->private;
1002         const struct xt_target *target;
1003
1004         switch (trav->class) {
1005         case MTTG_TRAV_NFP_UNSPEC:
1006         case MTTG_TRAV_NFP_SPEC:
1007                 if (trav->curr == trav->head)
1008                         return 0;
1009                 target = list_entry(trav->curr, struct xt_target, list);
1010                 return (*target->name == '\0') ? 0 :
1011                        seq_printf(seq, "%s\n", target->name);
1012         }
1013         return 0;
1014 }
1015
1016 static const struct seq_operations xt_target_seq_ops = {
1017         .start  = xt_target_seq_start,
1018         .next   = xt_target_seq_next,
1019         .stop   = xt_mttg_seq_stop,
1020         .show   = xt_target_seq_show,
1021 };
1022
1023 static int xt_target_open(struct inode *inode, struct file *file)
1024 {
1025         struct seq_file *seq;
1026         struct nf_mttg_trav *trav;
1027         int ret;
1028
1029         trav = kmalloc(sizeof(*trav), GFP_KERNEL);
1030         if (trav == NULL)
1031                 return -ENOMEM;
1032
1033         ret = seq_open(file, &xt_target_seq_ops);
1034         if (ret < 0) {
1035                 kfree(trav);
1036                 return ret;
1037         }
1038
1039         seq = file->private_data;
1040         seq->private = trav;
1041         trav->nfproto = (unsigned long)PDE(inode)->data;
1042         return 0;
1043 }
1044
1045 static const struct file_operations xt_target_ops = {
1046         .owner   = THIS_MODULE,
1047         .open    = xt_target_open,
1048         .read    = seq_read,
1049         .llseek  = seq_lseek,
1050         .release = seq_release_private,
1051 };
1052
1053 #define FORMAT_TABLES   "_tables_names"
1054 #define FORMAT_MATCHES  "_tables_matches"
1055 #define FORMAT_TARGETS  "_tables_targets"
1056
1057 #endif /* CONFIG_PROC_FS */
1058
1059 int xt_proto_init(struct net *net, u_int8_t af)
1060 {
1061 #ifdef CONFIG_PROC_FS
1062         char buf[XT_FUNCTION_MAXNAMELEN];
1063         struct proc_dir_entry *proc;
1064 #endif
1065
1066         if (af >= ARRAY_SIZE(xt_prefix))
1067                 return -EINVAL;
1068
1069
1070 #ifdef CONFIG_PROC_FS
1071         strlcpy(buf, xt_prefix[af], sizeof(buf));
1072         strlcat(buf, FORMAT_TABLES, sizeof(buf));
1073         proc = proc_create_data(buf, 0440, net->proc_net, &xt_table_ops,
1074                                 (void *)(unsigned long)af);
1075         if (!proc)
1076                 goto out;
1077
1078         strlcpy(buf, xt_prefix[af], sizeof(buf));
1079         strlcat(buf, FORMAT_MATCHES, sizeof(buf));
1080         proc = proc_create_data(buf, 0440, net->proc_net, &xt_match_ops,
1081                                 (void *)(unsigned long)af);
1082         if (!proc)
1083                 goto out_remove_tables;
1084
1085         strlcpy(buf, xt_prefix[af], sizeof(buf));
1086         strlcat(buf, FORMAT_TARGETS, sizeof(buf));
1087         proc = proc_create_data(buf, 0440, net->proc_net, &xt_target_ops,
1088                                 (void *)(unsigned long)af);
1089         if (!proc)
1090                 goto out_remove_matches;
1091 #endif
1092
1093         return 0;
1094
1095 #ifdef CONFIG_PROC_FS
1096 out_remove_matches:
1097         strlcpy(buf, xt_prefix[af], sizeof(buf));
1098         strlcat(buf, FORMAT_MATCHES, sizeof(buf));
1099         proc_net_remove(net, buf);
1100
1101 out_remove_tables:
1102         strlcpy(buf, xt_prefix[af], sizeof(buf));
1103         strlcat(buf, FORMAT_TABLES, sizeof(buf));
1104         proc_net_remove(net, buf);
1105 out:
1106         return -1;
1107 #endif
1108 }
1109 EXPORT_SYMBOL_GPL(xt_proto_init);
1110
1111 void xt_proto_fini(struct net *net, u_int8_t af)
1112 {
1113 #ifdef CONFIG_PROC_FS
1114         char buf[XT_FUNCTION_MAXNAMELEN];
1115
1116         strlcpy(buf, xt_prefix[af], sizeof(buf));
1117         strlcat(buf, FORMAT_TABLES, sizeof(buf));
1118         proc_net_remove(net, buf);
1119
1120         strlcpy(buf, xt_prefix[af], sizeof(buf));
1121         strlcat(buf, FORMAT_TARGETS, sizeof(buf));
1122         proc_net_remove(net, buf);
1123
1124         strlcpy(buf, xt_prefix[af], sizeof(buf));
1125         strlcat(buf, FORMAT_MATCHES, sizeof(buf));
1126         proc_net_remove(net, buf);
1127 #endif /*CONFIG_PROC_FS*/
1128 }
1129 EXPORT_SYMBOL_GPL(xt_proto_fini);
1130
1131 static int __net_init xt_net_init(struct net *net)
1132 {
1133         int i;
1134
1135         for (i = 0; i < NFPROTO_NUMPROTO; i++)
1136                 INIT_LIST_HEAD(&net->xt.tables[i]);
1137         return 0;
1138 }
1139
1140 static struct pernet_operations xt_net_ops = {
1141         .init = xt_net_init,
1142 };
1143
1144 static int __init xt_init(void)
1145 {
1146         unsigned int i;
1147         int rv;
1148
1149         for_each_possible_cpu(i) {
1150                 struct xt_info_lock *lock = &per_cpu(xt_info_locks, i);
1151                 spin_lock_init(&lock->lock);
1152                 lock->readers = 0;
1153         }
1154
1155         xt = kmalloc(sizeof(struct xt_af) * NFPROTO_NUMPROTO, GFP_KERNEL);
1156         if (!xt)
1157                 return -ENOMEM;
1158
1159         for (i = 0; i < NFPROTO_NUMPROTO; i++) {
1160                 mutex_init(&xt[i].mutex);
1161 #ifdef CONFIG_COMPAT
1162                 mutex_init(&xt[i].compat_mutex);
1163                 xt[i].compat_offsets = NULL;
1164 #endif
1165                 INIT_LIST_HEAD(&xt[i].target);
1166                 INIT_LIST_HEAD(&xt[i].match);
1167         }
1168         rv = register_pernet_subsys(&xt_net_ops);
1169         if (rv < 0)
1170                 kfree(xt);
1171         return rv;
1172 }
1173
1174 static void __exit xt_fini(void)
1175 {
1176         unregister_pernet_subsys(&xt_net_ops);
1177         kfree(xt);
1178 }
1179
1180 module_init(xt_init);
1181 module_exit(xt_fini);
1182