1 /* 2 * x_tables core - Backend for {ip,ip6,arp}_tables 3 * 4 * Copyright (C) 2006-2006 Harald Welte <laforge@netfilter.org> 5 * Copyright (C) 2006-2012 Patrick McHardy <kaber@trash.net> 6 * 7 * Based on existing ip_tables code which is 8 * Copyright (C) 1999 Paul `Rusty' Russell & Michael J. Neuling 9 * Copyright (C) 2000-2005 Netfilter Core Team <coreteam@netfilter.org> 10 * 11 * This program is free software; you can redistribute it and/or modify 12 * it under the terms of the GNU General Public License version 2 as 13 * published by the Free Software Foundation. 14 * 15 */ 16 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 17 #include <linux/kernel.h> 18 #include <linux/module.h> 19 #include <linux/socket.h> 20 #include <linux/net.h> 21 #include <linux/proc_fs.h> 22 #include <linux/seq_file.h> 23 #include <linux/string.h> 24 #include <linux/vmalloc.h> 25 #include <linux/mutex.h> 26 #include <linux/mm.h> 27 #include <linux/slab.h> 28 #include <linux/audit.h> 29 #include <net/net_namespace.h> 30 31 #include <linux/netfilter/x_tables.h> 32 #include <linux/netfilter_arp.h> 33 #include <linux/netfilter_ipv4/ip_tables.h> 34 #include <linux/netfilter_ipv6/ip6_tables.h> 35 #include <linux/netfilter_arp/arp_tables.h> 36 37 MODULE_LICENSE("GPL"); 38 MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>"); 39 MODULE_DESCRIPTION("{ip,ip6,arp,eb}_tables backend module"); 40 41 #define SMP_ALIGN(x) (((x) + SMP_CACHE_BYTES-1) & ~(SMP_CACHE_BYTES-1)) 42 43 struct compat_delta { 44 unsigned int offset; /* offset in kernel */ 45 int delta; /* delta in 32bit user land */ 46 }; 47 48 struct xt_af { 49 struct mutex mutex; 50 struct list_head match; 51 struct list_head target; 52 #ifdef CONFIG_COMPAT 53 struct mutex compat_mutex; 54 struct compat_delta *compat_tab; 55 unsigned int number; /* number of slots in compat_tab[] */ 56 unsigned int cur; /* number of used slots in compat_tab[] */ 57 #endif 58 }; 59 60 static struct xt_af *xt; 61 62 static const char *const xt_prefix[NFPROTO_NUMPROTO] = { 63 [NFPROTO_UNSPEC] = "x", 64 [NFPROTO_IPV4] = "ip", 65 [NFPROTO_ARP] = "arp", 66 [NFPROTO_BRIDGE] = "eb", 67 [NFPROTO_IPV6] = "ip6", 68 }; 69 70 /* Allow this many total (re)entries. */ 71 static const unsigned int xt_jumpstack_multiplier = 2; 72 73 /* Registration hooks for targets. */ 74 int xt_register_target(struct xt_target *target) 75 { 76 u_int8_t af = target->family; 77 78 mutex_lock(&xt[af].mutex); 79 list_add(&target->list, &xt[af].target); 80 mutex_unlock(&xt[af].mutex); 81 return 0; 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 while (n-- > 0) 120 xt_unregister_target(&target[n]); 121 } 122 EXPORT_SYMBOL(xt_unregister_targets); 123 124 int xt_register_match(struct xt_match *match) 125 { 126 u_int8_t af = match->family; 127 128 mutex_lock(&xt[af].mutex); 129 list_add(&match->list, &xt[af].match); 130 mutex_unlock(&xt[af].mutex); 131 return 0; 132 } 133 EXPORT_SYMBOL(xt_register_match); 134 135 void 136 xt_unregister_match(struct xt_match *match) 137 { 138 u_int8_t af = match->family; 139 140 mutex_lock(&xt[af].mutex); 141 list_del(&match->list); 142 mutex_unlock(&xt[af].mutex); 143 } 144 EXPORT_SYMBOL(xt_unregister_match); 145 146 int 147 xt_register_matches(struct xt_match *match, unsigned int n) 148 { 149 unsigned int i; 150 int err = 0; 151 152 for (i = 0; i < n; i++) { 153 err = xt_register_match(&match[i]); 154 if (err) 155 goto err; 156 } 157 return err; 158 159 err: 160 if (i > 0) 161 xt_unregister_matches(match, i); 162 return err; 163 } 164 EXPORT_SYMBOL(xt_register_matches); 165 166 void 167 xt_unregister_matches(struct xt_match *match, unsigned int n) 168 { 169 while (n-- > 0) 170 xt_unregister_match(&match[n]); 171 } 172 EXPORT_SYMBOL(xt_unregister_matches); 173 174 175 /* 176 * These are weird, but module loading must not be done with mutex 177 * held (since they will register), and we have to have a single 178 * function to use. 179 */ 180 181 /* Find match, grabs ref. Returns ERR_PTR() on error. */ 182 struct xt_match *xt_find_match(u8 af, const char *name, u8 revision) 183 { 184 struct xt_match *m; 185 int err = -ENOENT; 186 187 mutex_lock(&xt[af].mutex); 188 list_for_each_entry(m, &xt[af].match, list) { 189 if (strcmp(m->name, name) == 0) { 190 if (m->revision == revision) { 191 if (try_module_get(m->me)) { 192 mutex_unlock(&xt[af].mutex); 193 return m; 194 } 195 } else 196 err = -EPROTOTYPE; /* Found something. */ 197 } 198 } 199 mutex_unlock(&xt[af].mutex); 200 201 if (af != NFPROTO_UNSPEC) 202 /* Try searching again in the family-independent list */ 203 return xt_find_match(NFPROTO_UNSPEC, name, revision); 204 205 return ERR_PTR(err); 206 } 207 EXPORT_SYMBOL(xt_find_match); 208 209 struct xt_match * 210 xt_request_find_match(uint8_t nfproto, const char *name, uint8_t revision) 211 { 212 struct xt_match *match; 213 214 match = xt_find_match(nfproto, name, revision); 215 if (IS_ERR(match)) { 216 request_module("%st_%s", xt_prefix[nfproto], name); 217 match = xt_find_match(nfproto, name, revision); 218 } 219 220 return match; 221 } 222 EXPORT_SYMBOL_GPL(xt_request_find_match); 223 224 /* Find target, grabs ref. Returns ERR_PTR() on error. */ 225 struct xt_target *xt_find_target(u8 af, const char *name, u8 revision) 226 { 227 struct xt_target *t; 228 int err = -ENOENT; 229 230 mutex_lock(&xt[af].mutex); 231 list_for_each_entry(t, &xt[af].target, list) { 232 if (strcmp(t->name, name) == 0) { 233 if (t->revision == revision) { 234 if (try_module_get(t->me)) { 235 mutex_unlock(&xt[af].mutex); 236 return t; 237 } 238 } else 239 err = -EPROTOTYPE; /* Found something. */ 240 } 241 } 242 mutex_unlock(&xt[af].mutex); 243 244 if (af != NFPROTO_UNSPEC) 245 /* Try searching again in the family-independent list */ 246 return xt_find_target(NFPROTO_UNSPEC, name, revision); 247 248 return ERR_PTR(err); 249 } 250 EXPORT_SYMBOL(xt_find_target); 251 252 struct xt_target *xt_request_find_target(u8 af, const char *name, u8 revision) 253 { 254 struct xt_target *target; 255 256 target = xt_find_target(af, name, revision); 257 if (IS_ERR(target)) { 258 request_module("%st_%s", xt_prefix[af], name); 259 target = xt_find_target(af, name, revision); 260 } 261 262 return target; 263 } 264 EXPORT_SYMBOL_GPL(xt_request_find_target); 265 266 static int match_revfn(u8 af, const char *name, u8 revision, int *bestp) 267 { 268 const struct xt_match *m; 269 int have_rev = 0; 270 271 list_for_each_entry(m, &xt[af].match, list) { 272 if (strcmp(m->name, name) == 0) { 273 if (m->revision > *bestp) 274 *bestp = m->revision; 275 if (m->revision == revision) 276 have_rev = 1; 277 } 278 } 279 280 if (af != NFPROTO_UNSPEC && !have_rev) 281 return match_revfn(NFPROTO_UNSPEC, name, revision, bestp); 282 283 return have_rev; 284 } 285 286 static int target_revfn(u8 af, const char *name, u8 revision, int *bestp) 287 { 288 const struct xt_target *t; 289 int have_rev = 0; 290 291 list_for_each_entry(t, &xt[af].target, list) { 292 if (strcmp(t->name, name) == 0) { 293 if (t->revision > *bestp) 294 *bestp = t->revision; 295 if (t->revision == revision) 296 have_rev = 1; 297 } 298 } 299 300 if (af != NFPROTO_UNSPEC && !have_rev) 301 return target_revfn(NFPROTO_UNSPEC, name, revision, bestp); 302 303 return have_rev; 304 } 305 306 /* Returns true or false (if no such extension at all) */ 307 int xt_find_revision(u8 af, const char *name, u8 revision, int target, 308 int *err) 309 { 310 int have_rev, best = -1; 311 312 mutex_lock(&xt[af].mutex); 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 * 333 textify_hooks(char *buf, size_t size, unsigned int mask, uint8_t nfproto) 334 { 335 static const char *const inetbr_names[] = { 336 "PREROUTING", "INPUT", "FORWARD", 337 "OUTPUT", "POSTROUTING", "BROUTING", 338 }; 339 static const char *const arp_names[] = { 340 "INPUT", "FORWARD", "OUTPUT", 341 }; 342 const char *const *names; 343 unsigned int i, max; 344 char *p = buf; 345 bool np = false; 346 int res; 347 348 names = (nfproto == NFPROTO_ARP) ? arp_names : inetbr_names; 349 max = (nfproto == NFPROTO_ARP) ? ARRAY_SIZE(arp_names) : 350 ARRAY_SIZE(inetbr_names); 351 *p = '\0'; 352 for (i = 0; i < max; ++i) { 353 if (!(mask & (1 << i))) 354 continue; 355 res = snprintf(p, size, "%s%s", np ? "/" : "", names[i]); 356 if (res > 0) { 357 size -= res; 358 p += res; 359 } 360 np = true; 361 } 362 363 return buf; 364 } 365 366 int xt_check_match(struct xt_mtchk_param *par, 367 unsigned int size, u_int8_t proto, bool inv_proto) 368 { 369 int ret; 370 371 if (XT_ALIGN(par->match->matchsize) != size && 372 par->match->matchsize != -1) { 373 /* 374 * ebt_among is exempt from centralized matchsize checking 375 * because it uses a dynamic-size data set. 376 */ 377 pr_err("%s_tables: %s.%u match: invalid size " 378 "%u (kernel) != (user) %u\n", 379 xt_prefix[par->family], par->match->name, 380 par->match->revision, 381 XT_ALIGN(par->match->matchsize), size); 382 return -EINVAL; 383 } 384 if (par->match->table != NULL && 385 strcmp(par->match->table, par->table) != 0) { 386 pr_err("%s_tables: %s match: only valid in %s table, not %s\n", 387 xt_prefix[par->family], par->match->name, 388 par->match->table, par->table); 389 return -EINVAL; 390 } 391 if (par->match->hooks && (par->hook_mask & ~par->match->hooks) != 0) { 392 char used[64], allow[64]; 393 394 pr_err("%s_tables: %s match: used from hooks %s, but only " 395 "valid from %s\n", 396 xt_prefix[par->family], par->match->name, 397 textify_hooks(used, sizeof(used), par->hook_mask, 398 par->family), 399 textify_hooks(allow, sizeof(allow), par->match->hooks, 400 par->family)); 401 return -EINVAL; 402 } 403 if (par->match->proto && (par->match->proto != proto || inv_proto)) { 404 pr_err("%s_tables: %s match: only valid for protocol %u\n", 405 xt_prefix[par->family], par->match->name, 406 par->match->proto); 407 return -EINVAL; 408 } 409 if (par->match->checkentry != NULL) { 410 ret = par->match->checkentry(par); 411 if (ret < 0) 412 return ret; 413 else if (ret > 0) 414 /* Flag up potential errors. */ 415 return -EIO; 416 } 417 return 0; 418 } 419 EXPORT_SYMBOL_GPL(xt_check_match); 420 421 #ifdef CONFIG_COMPAT 422 int xt_compat_add_offset(u_int8_t af, unsigned int offset, int delta) 423 { 424 struct xt_af *xp = &xt[af]; 425 426 if (!xp->compat_tab) { 427 if (!xp->number) 428 return -EINVAL; 429 xp->compat_tab = vmalloc(sizeof(struct compat_delta) * xp->number); 430 if (!xp->compat_tab) 431 return -ENOMEM; 432 xp->cur = 0; 433 } 434 435 if (xp->cur >= xp->number) 436 return -EINVAL; 437 438 if (xp->cur) 439 delta += xp->compat_tab[xp->cur - 1].delta; 440 xp->compat_tab[xp->cur].offset = offset; 441 xp->compat_tab[xp->cur].delta = delta; 442 xp->cur++; 443 return 0; 444 } 445 EXPORT_SYMBOL_GPL(xt_compat_add_offset); 446 447 void xt_compat_flush_offsets(u_int8_t af) 448 { 449 if (xt[af].compat_tab) { 450 vfree(xt[af].compat_tab); 451 xt[af].compat_tab = NULL; 452 xt[af].number = 0; 453 xt[af].cur = 0; 454 } 455 } 456 EXPORT_SYMBOL_GPL(xt_compat_flush_offsets); 457 458 int xt_compat_calc_jump(u_int8_t af, unsigned int offset) 459 { 460 struct compat_delta *tmp = xt[af].compat_tab; 461 int mid, left = 0, right = xt[af].cur - 1; 462 463 while (left <= right) { 464 mid = (left + right) >> 1; 465 if (offset > tmp[mid].offset) 466 left = mid + 1; 467 else if (offset < tmp[mid].offset) 468 right = mid - 1; 469 else 470 return mid ? tmp[mid - 1].delta : 0; 471 } 472 return left ? tmp[left - 1].delta : 0; 473 } 474 EXPORT_SYMBOL_GPL(xt_compat_calc_jump); 475 476 void xt_compat_init_offsets(u_int8_t af, unsigned int number) 477 { 478 xt[af].number = number; 479 xt[af].cur = 0; 480 } 481 EXPORT_SYMBOL(xt_compat_init_offsets); 482 483 int xt_compat_match_offset(const struct xt_match *match) 484 { 485 u_int16_t csize = match->compatsize ? : match->matchsize; 486 return XT_ALIGN(match->matchsize) - COMPAT_XT_ALIGN(csize); 487 } 488 EXPORT_SYMBOL_GPL(xt_compat_match_offset); 489 490 int xt_compat_match_from_user(struct xt_entry_match *m, void **dstptr, 491 unsigned int *size) 492 { 493 const struct xt_match *match = m->u.kernel.match; 494 struct compat_xt_entry_match *cm = (struct compat_xt_entry_match *)m; 495 int pad, off = xt_compat_match_offset(match); 496 u_int16_t msize = cm->u.user.match_size; 497 498 m = *dstptr; 499 memcpy(m, cm, sizeof(*cm)); 500 if (match->compat_from_user) 501 match->compat_from_user(m->data, cm->data); 502 else 503 memcpy(m->data, cm->data, msize - sizeof(*cm)); 504 pad = XT_ALIGN(match->matchsize) - match->matchsize; 505 if (pad > 0) 506 memset(m->data + match->matchsize, 0, pad); 507 508 msize += off; 509 m->u.user.match_size = msize; 510 511 *size += off; 512 *dstptr += msize; 513 return 0; 514 } 515 EXPORT_SYMBOL_GPL(xt_compat_match_from_user); 516 517 int xt_compat_match_to_user(const struct xt_entry_match *m, 518 void __user **dstptr, unsigned int *size) 519 { 520 const struct xt_match *match = m->u.kernel.match; 521 struct compat_xt_entry_match __user *cm = *dstptr; 522 int off = xt_compat_match_offset(match); 523 u_int16_t msize = m->u.user.match_size - off; 524 525 if (copy_to_user(cm, m, sizeof(*cm)) || 526 put_user(msize, &cm->u.user.match_size) || 527 copy_to_user(cm->u.user.name, m->u.kernel.match->name, 528 strlen(m->u.kernel.match->name) + 1)) 529 return -EFAULT; 530 531 if (match->compat_to_user) { 532 if (match->compat_to_user((void __user *)cm->data, m->data)) 533 return -EFAULT; 534 } else { 535 if (copy_to_user(cm->data, m->data, msize - sizeof(*cm))) 536 return -EFAULT; 537 } 538 539 *size -= off; 540 *dstptr += msize; 541 return 0; 542 } 543 EXPORT_SYMBOL_GPL(xt_compat_match_to_user); 544 #endif /* CONFIG_COMPAT */ 545 546 int xt_check_target(struct xt_tgchk_param *par, 547 unsigned int size, u_int8_t proto, bool inv_proto) 548 { 549 int ret; 550 551 if (XT_ALIGN(par->target->targetsize) != size) { 552 pr_err("%s_tables: %s.%u target: invalid size " 553 "%u (kernel) != (user) %u\n", 554 xt_prefix[par->family], par->target->name, 555 par->target->revision, 556 XT_ALIGN(par->target->targetsize), size); 557 return -EINVAL; 558 } 559 if (par->target->table != NULL && 560 strcmp(par->target->table, par->table) != 0) { 561 pr_err("%s_tables: %s target: only valid in %s table, not %s\n", 562 xt_prefix[par->family], par->target->name, 563 par->target->table, par->table); 564 return -EINVAL; 565 } 566 if (par->target->hooks && (par->hook_mask & ~par->target->hooks) != 0) { 567 char used[64], allow[64]; 568 569 pr_err("%s_tables: %s target: used from hooks %s, but only " 570 "usable from %s\n", 571 xt_prefix[par->family], par->target->name, 572 textify_hooks(used, sizeof(used), par->hook_mask, 573 par->family), 574 textify_hooks(allow, sizeof(allow), par->target->hooks, 575 par->family)); 576 return -EINVAL; 577 } 578 if (par->target->proto && (par->target->proto != proto || inv_proto)) { 579 pr_err("%s_tables: %s target: only valid for protocol %u\n", 580 xt_prefix[par->family], par->target->name, 581 par->target->proto); 582 return -EINVAL; 583 } 584 if (par->target->checkentry != NULL) { 585 ret = par->target->checkentry(par); 586 if (ret < 0) 587 return ret; 588 else if (ret > 0) 589 /* Flag up potential errors. */ 590 return -EIO; 591 } 592 return 0; 593 } 594 EXPORT_SYMBOL_GPL(xt_check_target); 595 596 #ifdef CONFIG_COMPAT 597 int xt_compat_target_offset(const struct xt_target *target) 598 { 599 u_int16_t csize = target->compatsize ? : target->targetsize; 600 return XT_ALIGN(target->targetsize) - COMPAT_XT_ALIGN(csize); 601 } 602 EXPORT_SYMBOL_GPL(xt_compat_target_offset); 603 604 void xt_compat_target_from_user(struct xt_entry_target *t, void **dstptr, 605 unsigned int *size) 606 { 607 const struct xt_target *target = t->u.kernel.target; 608 struct compat_xt_entry_target *ct = (struct compat_xt_entry_target *)t; 609 int pad, off = xt_compat_target_offset(target); 610 u_int16_t tsize = ct->u.user.target_size; 611 612 t = *dstptr; 613 memcpy(t, ct, sizeof(*ct)); 614 if (target->compat_from_user) 615 target->compat_from_user(t->data, ct->data); 616 else 617 memcpy(t->data, ct->data, tsize - sizeof(*ct)); 618 pad = XT_ALIGN(target->targetsize) - target->targetsize; 619 if (pad > 0) 620 memset(t->data + target->targetsize, 0, pad); 621 622 tsize += off; 623 t->u.user.target_size = tsize; 624 625 *size += off; 626 *dstptr += tsize; 627 } 628 EXPORT_SYMBOL_GPL(xt_compat_target_from_user); 629 630 int xt_compat_target_to_user(const struct xt_entry_target *t, 631 void __user **dstptr, unsigned int *size) 632 { 633 const struct xt_target *target = t->u.kernel.target; 634 struct compat_xt_entry_target __user *ct = *dstptr; 635 int off = xt_compat_target_offset(target); 636 u_int16_t tsize = t->u.user.target_size - off; 637 638 if (copy_to_user(ct, t, sizeof(*ct)) || 639 put_user(tsize, &ct->u.user.target_size) || 640 copy_to_user(ct->u.user.name, t->u.kernel.target->name, 641 strlen(t->u.kernel.target->name) + 1)) 642 return -EFAULT; 643 644 if (target->compat_to_user) { 645 if (target->compat_to_user((void __user *)ct->data, t->data)) 646 return -EFAULT; 647 } else { 648 if (copy_to_user(ct->data, t->data, tsize - sizeof(*ct))) 649 return -EFAULT; 650 } 651 652 *size -= off; 653 *dstptr += tsize; 654 return 0; 655 } 656 EXPORT_SYMBOL_GPL(xt_compat_target_to_user); 657 #endif 658 659 struct xt_table_info *xt_alloc_table_info(unsigned int size) 660 { 661 struct xt_table_info *info = NULL; 662 size_t sz = sizeof(*info) + size; 663 664 /* Pedantry: prevent them from hitting BUG() in vmalloc.c --RR */ 665 if ((SMP_ALIGN(size) >> PAGE_SHIFT) + 2 > totalram_pages) 666 return NULL; 667 668 if (sz <= (PAGE_SIZE << PAGE_ALLOC_COSTLY_ORDER)) 669 info = kmalloc(sz, GFP_KERNEL | __GFP_NOWARN | __GFP_NORETRY); 670 if (!info) { 671 info = vmalloc(sz); 672 if (!info) 673 return NULL; 674 } 675 memset(info, 0, sizeof(*info)); 676 info->size = size; 677 return info; 678 } 679 EXPORT_SYMBOL(xt_alloc_table_info); 680 681 void xt_free_table_info(struct xt_table_info *info) 682 { 683 int cpu; 684 685 if (info->jumpstack != NULL) { 686 for_each_possible_cpu(cpu) 687 kvfree(info->jumpstack[cpu]); 688 kvfree(info->jumpstack); 689 } 690 691 free_percpu(info->stackptr); 692 693 kvfree(info); 694 } 695 EXPORT_SYMBOL(xt_free_table_info); 696 697 /* Find table by name, grabs mutex & ref. Returns ERR_PTR() on error. */ 698 struct xt_table *xt_find_table_lock(struct net *net, u_int8_t af, 699 const char *name) 700 { 701 struct xt_table *t; 702 703 mutex_lock(&xt[af].mutex); 704 list_for_each_entry(t, &net->xt.tables[af], list) 705 if (strcmp(t->name, name) == 0 && try_module_get(t->me)) 706 return t; 707 mutex_unlock(&xt[af].mutex); 708 return NULL; 709 } 710 EXPORT_SYMBOL_GPL(xt_find_table_lock); 711 712 void xt_table_unlock(struct xt_table *table) 713 { 714 mutex_unlock(&xt[table->af].mutex); 715 } 716 EXPORT_SYMBOL_GPL(xt_table_unlock); 717 718 #ifdef CONFIG_COMPAT 719 void xt_compat_lock(u_int8_t af) 720 { 721 mutex_lock(&xt[af].compat_mutex); 722 } 723 EXPORT_SYMBOL_GPL(xt_compat_lock); 724 725 void xt_compat_unlock(u_int8_t af) 726 { 727 mutex_unlock(&xt[af].compat_mutex); 728 } 729 EXPORT_SYMBOL_GPL(xt_compat_unlock); 730 #endif 731 732 DEFINE_PER_CPU(seqcount_t, xt_recseq); 733 EXPORT_PER_CPU_SYMBOL_GPL(xt_recseq); 734 735 static int xt_jumpstack_alloc(struct xt_table_info *i) 736 { 737 unsigned int size; 738 int cpu; 739 740 i->stackptr = alloc_percpu(unsigned int); 741 if (i->stackptr == NULL) 742 return -ENOMEM; 743 744 size = sizeof(void **) * nr_cpu_ids; 745 if (size > PAGE_SIZE) 746 i->jumpstack = vzalloc(size); 747 else 748 i->jumpstack = kzalloc(size, GFP_KERNEL); 749 if (i->jumpstack == NULL) 750 return -ENOMEM; 751 752 i->stacksize *= xt_jumpstack_multiplier; 753 size = sizeof(void *) * i->stacksize; 754 for_each_possible_cpu(cpu) { 755 if (size > PAGE_SIZE) 756 i->jumpstack[cpu] = vmalloc_node(size, 757 cpu_to_node(cpu)); 758 else 759 i->jumpstack[cpu] = kmalloc_node(size, 760 GFP_KERNEL, cpu_to_node(cpu)); 761 if (i->jumpstack[cpu] == NULL) 762 /* 763 * Freeing will be done later on by the callers. The 764 * chain is: xt_replace_table -> __do_replace -> 765 * do_replace -> xt_free_table_info. 766 */ 767 return -ENOMEM; 768 } 769 770 return 0; 771 } 772 773 struct xt_table_info * 774 xt_replace_table(struct xt_table *table, 775 unsigned int num_counters, 776 struct xt_table_info *newinfo, 777 int *error) 778 { 779 struct xt_table_info *private; 780 int ret; 781 782 ret = xt_jumpstack_alloc(newinfo); 783 if (ret < 0) { 784 *error = ret; 785 return NULL; 786 } 787 788 /* Do the substitution. */ 789 local_bh_disable(); 790 private = table->private; 791 792 /* Check inside lock: is the old number correct? */ 793 if (num_counters != private->number) { 794 pr_debug("num_counters != table->private->number (%u/%u)\n", 795 num_counters, private->number); 796 local_bh_enable(); 797 *error = -EAGAIN; 798 return NULL; 799 } 800 801 newinfo->initial_entries = private->initial_entries; 802 /* 803 * Ensure contents of newinfo are visible before assigning to 804 * private. 805 */ 806 smp_wmb(); 807 table->private = newinfo; 808 809 /* 810 * Even though table entries have now been swapped, other CPU's 811 * may still be using the old entries. This is okay, because 812 * resynchronization happens because of the locking done 813 * during the get_counters() routine. 814 */ 815 local_bh_enable(); 816 817 #ifdef CONFIG_AUDIT 818 if (audit_enabled) { 819 struct audit_buffer *ab; 820 821 ab = audit_log_start(current->audit_context, GFP_KERNEL, 822 AUDIT_NETFILTER_CFG); 823 if (ab) { 824 audit_log_format(ab, "table=%s family=%u entries=%u", 825 table->name, table->af, 826 private->number); 827 audit_log_end(ab); 828 } 829 } 830 #endif 831 832 return private; 833 } 834 EXPORT_SYMBOL_GPL(xt_replace_table); 835 836 struct xt_table *xt_register_table(struct net *net, 837 const struct xt_table *input_table, 838 struct xt_table_info *bootstrap, 839 struct xt_table_info *newinfo) 840 { 841 int ret; 842 struct xt_table_info *private; 843 struct xt_table *t, *table; 844 845 /* Don't add one object to multiple lists. */ 846 table = kmemdup(input_table, sizeof(struct xt_table), GFP_KERNEL); 847 if (!table) { 848 ret = -ENOMEM; 849 goto out; 850 } 851 852 mutex_lock(&xt[table->af].mutex); 853 /* Don't autoload: we'd eat our tail... */ 854 list_for_each_entry(t, &net->xt.tables[table->af], list) { 855 if (strcmp(t->name, table->name) == 0) { 856 ret = -EEXIST; 857 goto unlock; 858 } 859 } 860 861 /* Simplifies replace_table code. */ 862 table->private = bootstrap; 863 864 if (!xt_replace_table(table, 0, newinfo, &ret)) 865 goto unlock; 866 867 private = table->private; 868 pr_debug("table->private->number = %u\n", private->number); 869 870 /* save number of initial entries */ 871 private->initial_entries = private->number; 872 873 list_add(&table->list, &net->xt.tables[table->af]); 874 mutex_unlock(&xt[table->af].mutex); 875 return table; 876 877 unlock: 878 mutex_unlock(&xt[table->af].mutex); 879 kfree(table); 880 out: 881 return ERR_PTR(ret); 882 } 883 EXPORT_SYMBOL_GPL(xt_register_table); 884 885 void *xt_unregister_table(struct xt_table *table) 886 { 887 struct xt_table_info *private; 888 889 mutex_lock(&xt[table->af].mutex); 890 private = table->private; 891 list_del(&table->list); 892 mutex_unlock(&xt[table->af].mutex); 893 kfree(table); 894 895 return private; 896 } 897 EXPORT_SYMBOL_GPL(xt_unregister_table); 898 899 #ifdef CONFIG_PROC_FS 900 struct xt_names_priv { 901 struct seq_net_private p; 902 u_int8_t af; 903 }; 904 static void *xt_table_seq_start(struct seq_file *seq, loff_t *pos) 905 { 906 struct xt_names_priv *priv = seq->private; 907 struct net *net = seq_file_net(seq); 908 u_int8_t af = priv->af; 909 910 mutex_lock(&xt[af].mutex); 911 return seq_list_start(&net->xt.tables[af], *pos); 912 } 913 914 static void *xt_table_seq_next(struct seq_file *seq, void *v, loff_t *pos) 915 { 916 struct xt_names_priv *priv = seq->private; 917 struct net *net = seq_file_net(seq); 918 u_int8_t af = priv->af; 919 920 return seq_list_next(v, &net->xt.tables[af], pos); 921 } 922 923 static void xt_table_seq_stop(struct seq_file *seq, void *v) 924 { 925 struct xt_names_priv *priv = seq->private; 926 u_int8_t af = priv->af; 927 928 mutex_unlock(&xt[af].mutex); 929 } 930 931 static int xt_table_seq_show(struct seq_file *seq, void *v) 932 { 933 struct xt_table *table = list_entry(v, struct xt_table, list); 934 935 if (*table->name) 936 seq_printf(seq, "%s\n", table->name); 937 return 0; 938 } 939 940 static const struct seq_operations xt_table_seq_ops = { 941 .start = xt_table_seq_start, 942 .next = xt_table_seq_next, 943 .stop = xt_table_seq_stop, 944 .show = xt_table_seq_show, 945 }; 946 947 static int xt_table_open(struct inode *inode, struct file *file) 948 { 949 int ret; 950 struct xt_names_priv *priv; 951 952 ret = seq_open_net(inode, file, &xt_table_seq_ops, 953 sizeof(struct xt_names_priv)); 954 if (!ret) { 955 priv = ((struct seq_file *)file->private_data)->private; 956 priv->af = (unsigned long)PDE_DATA(inode); 957 } 958 return ret; 959 } 960 961 static const struct file_operations xt_table_ops = { 962 .owner = THIS_MODULE, 963 .open = xt_table_open, 964 .read = seq_read, 965 .llseek = seq_lseek, 966 .release = seq_release_net, 967 }; 968 969 /* 970 * Traverse state for ip{,6}_{tables,matches} for helping crossing 971 * the multi-AF mutexes. 972 */ 973 struct nf_mttg_trav { 974 struct list_head *head, *curr; 975 uint8_t class, nfproto; 976 }; 977 978 enum { 979 MTTG_TRAV_INIT, 980 MTTG_TRAV_NFP_UNSPEC, 981 MTTG_TRAV_NFP_SPEC, 982 MTTG_TRAV_DONE, 983 }; 984 985 static void *xt_mttg_seq_next(struct seq_file *seq, void *v, loff_t *ppos, 986 bool is_target) 987 { 988 static const uint8_t next_class[] = { 989 [MTTG_TRAV_NFP_UNSPEC] = MTTG_TRAV_NFP_SPEC, 990 [MTTG_TRAV_NFP_SPEC] = MTTG_TRAV_DONE, 991 }; 992 struct nf_mttg_trav *trav = seq->private; 993 994 switch (trav->class) { 995 case MTTG_TRAV_INIT: 996 trav->class = MTTG_TRAV_NFP_UNSPEC; 997 mutex_lock(&xt[NFPROTO_UNSPEC].mutex); 998 trav->head = trav->curr = is_target ? 999 &xt[NFPROTO_UNSPEC].target : &xt[NFPROTO_UNSPEC].match; 1000 break; 1001 case MTTG_TRAV_NFP_UNSPEC: 1002 trav->curr = trav->curr->next; 1003 if (trav->curr != trav->head) 1004 break; 1005 mutex_unlock(&xt[NFPROTO_UNSPEC].mutex); 1006 mutex_lock(&xt[trav->nfproto].mutex); 1007 trav->head = trav->curr = is_target ? 1008 &xt[trav->nfproto].target : &xt[trav->nfproto].match; 1009 trav->class = next_class[trav->class]; 1010 break; 1011 case MTTG_TRAV_NFP_SPEC: 1012 trav->curr = trav->curr->next; 1013 if (trav->curr != trav->head) 1014 break; 1015 /* fallthru, _stop will unlock */ 1016 default: 1017 return NULL; 1018 } 1019 1020 if (ppos != NULL) 1021 ++*ppos; 1022 return trav; 1023 } 1024 1025 static void *xt_mttg_seq_start(struct seq_file *seq, loff_t *pos, 1026 bool is_target) 1027 { 1028 struct nf_mttg_trav *trav = seq->private; 1029 unsigned int j; 1030 1031 trav->class = MTTG_TRAV_INIT; 1032 for (j = 0; j < *pos; ++j) 1033 if (xt_mttg_seq_next(seq, NULL, NULL, is_target) == NULL) 1034 return NULL; 1035 return trav; 1036 } 1037 1038 static void xt_mttg_seq_stop(struct seq_file *seq, void *v) 1039 { 1040 struct nf_mttg_trav *trav = seq->private; 1041 1042 switch (trav->class) { 1043 case MTTG_TRAV_NFP_UNSPEC: 1044 mutex_unlock(&xt[NFPROTO_UNSPEC].mutex); 1045 break; 1046 case MTTG_TRAV_NFP_SPEC: 1047 mutex_unlock(&xt[trav->nfproto].mutex); 1048 break; 1049 } 1050 } 1051 1052 static void *xt_match_seq_start(struct seq_file *seq, loff_t *pos) 1053 { 1054 return xt_mttg_seq_start(seq, pos, false); 1055 } 1056 1057 static void *xt_match_seq_next(struct seq_file *seq, void *v, loff_t *ppos) 1058 { 1059 return xt_mttg_seq_next(seq, v, ppos, false); 1060 } 1061 1062 static int xt_match_seq_show(struct seq_file *seq, void *v) 1063 { 1064 const struct nf_mttg_trav *trav = seq->private; 1065 const struct xt_match *match; 1066 1067 switch (trav->class) { 1068 case MTTG_TRAV_NFP_UNSPEC: 1069 case MTTG_TRAV_NFP_SPEC: 1070 if (trav->curr == trav->head) 1071 return 0; 1072 match = list_entry(trav->curr, struct xt_match, list); 1073 if (*match->name) 1074 seq_printf(seq, "%s\n", match->name); 1075 } 1076 return 0; 1077 } 1078 1079 static const struct seq_operations xt_match_seq_ops = { 1080 .start = xt_match_seq_start, 1081 .next = xt_match_seq_next, 1082 .stop = xt_mttg_seq_stop, 1083 .show = xt_match_seq_show, 1084 }; 1085 1086 static int xt_match_open(struct inode *inode, struct file *file) 1087 { 1088 struct nf_mttg_trav *trav; 1089 trav = __seq_open_private(file, &xt_match_seq_ops, sizeof(*trav)); 1090 if (!trav) 1091 return -ENOMEM; 1092 1093 trav->nfproto = (unsigned long)PDE_DATA(inode); 1094 return 0; 1095 } 1096 1097 static const struct file_operations xt_match_ops = { 1098 .owner = THIS_MODULE, 1099 .open = xt_match_open, 1100 .read = seq_read, 1101 .llseek = seq_lseek, 1102 .release = seq_release_private, 1103 }; 1104 1105 static void *xt_target_seq_start(struct seq_file *seq, loff_t *pos) 1106 { 1107 return xt_mttg_seq_start(seq, pos, true); 1108 } 1109 1110 static void *xt_target_seq_next(struct seq_file *seq, void *v, loff_t *ppos) 1111 { 1112 return xt_mttg_seq_next(seq, v, ppos, true); 1113 } 1114 1115 static int xt_target_seq_show(struct seq_file *seq, void *v) 1116 { 1117 const struct nf_mttg_trav *trav = seq->private; 1118 const struct xt_target *target; 1119 1120 switch (trav->class) { 1121 case MTTG_TRAV_NFP_UNSPEC: 1122 case MTTG_TRAV_NFP_SPEC: 1123 if (trav->curr == trav->head) 1124 return 0; 1125 target = list_entry(trav->curr, struct xt_target, list); 1126 if (*target->name) 1127 seq_printf(seq, "%s\n", target->name); 1128 } 1129 return 0; 1130 } 1131 1132 static const struct seq_operations xt_target_seq_ops = { 1133 .start = xt_target_seq_start, 1134 .next = xt_target_seq_next, 1135 .stop = xt_mttg_seq_stop, 1136 .show = xt_target_seq_show, 1137 }; 1138 1139 static int xt_target_open(struct inode *inode, struct file *file) 1140 { 1141 struct nf_mttg_trav *trav; 1142 trav = __seq_open_private(file, &xt_target_seq_ops, sizeof(*trav)); 1143 if (!trav) 1144 return -ENOMEM; 1145 1146 trav->nfproto = (unsigned long)PDE_DATA(inode); 1147 return 0; 1148 } 1149 1150 static const struct file_operations xt_target_ops = { 1151 .owner = THIS_MODULE, 1152 .open = xt_target_open, 1153 .read = seq_read, 1154 .llseek = seq_lseek, 1155 .release = seq_release_private, 1156 }; 1157 1158 #define FORMAT_TABLES "_tables_names" 1159 #define FORMAT_MATCHES "_tables_matches" 1160 #define FORMAT_TARGETS "_tables_targets" 1161 1162 #endif /* CONFIG_PROC_FS */ 1163 1164 /** 1165 * xt_hook_link - set up hooks for a new table 1166 * @table: table with metadata needed to set up hooks 1167 * @fn: Hook function 1168 * 1169 * This function will take care of creating and registering the necessary 1170 * Netfilter hooks for XT tables. 1171 */ 1172 struct nf_hook_ops *xt_hook_link(const struct xt_table *table, nf_hookfn *fn) 1173 { 1174 unsigned int hook_mask = table->valid_hooks; 1175 uint8_t i, num_hooks = hweight32(hook_mask); 1176 uint8_t hooknum; 1177 struct nf_hook_ops *ops; 1178 int ret; 1179 1180 ops = kmalloc(sizeof(*ops) * num_hooks, GFP_KERNEL); 1181 if (ops == NULL) 1182 return ERR_PTR(-ENOMEM); 1183 1184 for (i = 0, hooknum = 0; i < num_hooks && hook_mask != 0; 1185 hook_mask >>= 1, ++hooknum) { 1186 if (!(hook_mask & 1)) 1187 continue; 1188 ops[i].hook = fn; 1189 ops[i].owner = table->me; 1190 ops[i].pf = table->af; 1191 ops[i].hooknum = hooknum; 1192 ops[i].priority = table->priority; 1193 ++i; 1194 } 1195 1196 ret = nf_register_hooks(ops, num_hooks); 1197 if (ret < 0) { 1198 kfree(ops); 1199 return ERR_PTR(ret); 1200 } 1201 1202 return ops; 1203 } 1204 EXPORT_SYMBOL_GPL(xt_hook_link); 1205 1206 /** 1207 * xt_hook_unlink - remove hooks for a table 1208 * @ops: nf_hook_ops array as returned by nf_hook_link 1209 * @hook_mask: the very same mask that was passed to nf_hook_link 1210 */ 1211 void xt_hook_unlink(const struct xt_table *table, struct nf_hook_ops *ops) 1212 { 1213 nf_unregister_hooks(ops, hweight32(table->valid_hooks)); 1214 kfree(ops); 1215 } 1216 EXPORT_SYMBOL_GPL(xt_hook_unlink); 1217 1218 int xt_proto_init(struct net *net, u_int8_t af) 1219 { 1220 #ifdef CONFIG_PROC_FS 1221 char buf[XT_FUNCTION_MAXNAMELEN]; 1222 struct proc_dir_entry *proc; 1223 #endif 1224 1225 if (af >= ARRAY_SIZE(xt_prefix)) 1226 return -EINVAL; 1227 1228 1229 #ifdef CONFIG_PROC_FS 1230 strlcpy(buf, xt_prefix[af], sizeof(buf)); 1231 strlcat(buf, FORMAT_TABLES, sizeof(buf)); 1232 proc = proc_create_data(buf, 0440, net->proc_net, &xt_table_ops, 1233 (void *)(unsigned long)af); 1234 if (!proc) 1235 goto out; 1236 1237 strlcpy(buf, xt_prefix[af], sizeof(buf)); 1238 strlcat(buf, FORMAT_MATCHES, sizeof(buf)); 1239 proc = proc_create_data(buf, 0440, net->proc_net, &xt_match_ops, 1240 (void *)(unsigned long)af); 1241 if (!proc) 1242 goto out_remove_tables; 1243 1244 strlcpy(buf, xt_prefix[af], sizeof(buf)); 1245 strlcat(buf, FORMAT_TARGETS, sizeof(buf)); 1246 proc = proc_create_data(buf, 0440, net->proc_net, &xt_target_ops, 1247 (void *)(unsigned long)af); 1248 if (!proc) 1249 goto out_remove_matches; 1250 #endif 1251 1252 return 0; 1253 1254 #ifdef CONFIG_PROC_FS 1255 out_remove_matches: 1256 strlcpy(buf, xt_prefix[af], sizeof(buf)); 1257 strlcat(buf, FORMAT_MATCHES, sizeof(buf)); 1258 remove_proc_entry(buf, net->proc_net); 1259 1260 out_remove_tables: 1261 strlcpy(buf, xt_prefix[af], sizeof(buf)); 1262 strlcat(buf, FORMAT_TABLES, sizeof(buf)); 1263 remove_proc_entry(buf, net->proc_net); 1264 out: 1265 return -1; 1266 #endif 1267 } 1268 EXPORT_SYMBOL_GPL(xt_proto_init); 1269 1270 void xt_proto_fini(struct net *net, u_int8_t af) 1271 { 1272 #ifdef CONFIG_PROC_FS 1273 char buf[XT_FUNCTION_MAXNAMELEN]; 1274 1275 strlcpy(buf, xt_prefix[af], sizeof(buf)); 1276 strlcat(buf, FORMAT_TABLES, sizeof(buf)); 1277 remove_proc_entry(buf, net->proc_net); 1278 1279 strlcpy(buf, xt_prefix[af], sizeof(buf)); 1280 strlcat(buf, FORMAT_TARGETS, sizeof(buf)); 1281 remove_proc_entry(buf, net->proc_net); 1282 1283 strlcpy(buf, xt_prefix[af], sizeof(buf)); 1284 strlcat(buf, FORMAT_MATCHES, sizeof(buf)); 1285 remove_proc_entry(buf, net->proc_net); 1286 #endif /*CONFIG_PROC_FS*/ 1287 } 1288 EXPORT_SYMBOL_GPL(xt_proto_fini); 1289 1290 static int __net_init xt_net_init(struct net *net) 1291 { 1292 int i; 1293 1294 for (i = 0; i < NFPROTO_NUMPROTO; i++) 1295 INIT_LIST_HEAD(&net->xt.tables[i]); 1296 return 0; 1297 } 1298 1299 static struct pernet_operations xt_net_ops = { 1300 .init = xt_net_init, 1301 }; 1302 1303 static int __init xt_init(void) 1304 { 1305 unsigned int i; 1306 int rv; 1307 1308 for_each_possible_cpu(i) { 1309 seqcount_init(&per_cpu(xt_recseq, i)); 1310 } 1311 1312 xt = kmalloc(sizeof(struct xt_af) * NFPROTO_NUMPROTO, GFP_KERNEL); 1313 if (!xt) 1314 return -ENOMEM; 1315 1316 for (i = 0; i < NFPROTO_NUMPROTO; i++) { 1317 mutex_init(&xt[i].mutex); 1318 #ifdef CONFIG_COMPAT 1319 mutex_init(&xt[i].compat_mutex); 1320 xt[i].compat_tab = NULL; 1321 #endif 1322 INIT_LIST_HEAD(&xt[i].target); 1323 INIT_LIST_HEAD(&xt[i].match); 1324 } 1325 rv = register_pernet_subsys(&xt_net_ops); 1326 if (rv < 0) 1327 kfree(xt); 1328 return rv; 1329 } 1330 1331 static void __exit xt_fini(void) 1332 { 1333 unregister_pernet_subsys(&xt_net_ops); 1334 kfree(xt); 1335 } 1336 1337 module_init(xt_init); 1338 module_exit(xt_fini); 1339 1340