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 <linux/user_namespace.h> 30 #include <net/net_namespace.h> 31 32 #include <linux/netfilter/x_tables.h> 33 #include <linux/netfilter_arp.h> 34 #include <linux/netfilter_ipv4/ip_tables.h> 35 #include <linux/netfilter_ipv6/ip6_tables.h> 36 #include <linux/netfilter_arp/arp_tables.h> 37 38 MODULE_LICENSE("GPL"); 39 MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>"); 40 MODULE_DESCRIPTION("{ip,ip6,arp,eb}_tables backend module"); 41 42 #define XT_PCPU_BLOCK_SIZE 4096 43 #define XT_MAX_TABLE_SIZE (512 * 1024 * 1024) 44 45 struct compat_delta { 46 unsigned int offset; /* offset in kernel */ 47 int delta; /* delta in 32bit user land */ 48 }; 49 50 struct xt_af { 51 struct mutex mutex; 52 struct list_head match; 53 struct list_head target; 54 #ifdef CONFIG_COMPAT 55 struct mutex compat_mutex; 56 struct compat_delta *compat_tab; 57 unsigned int number; /* number of slots in compat_tab[] */ 58 unsigned int cur; /* number of used slots in compat_tab[] */ 59 #endif 60 }; 61 62 static struct xt_af *xt; 63 64 static const char *const xt_prefix[NFPROTO_NUMPROTO] = { 65 [NFPROTO_UNSPEC] = "x", 66 [NFPROTO_IPV4] = "ip", 67 [NFPROTO_ARP] = "arp", 68 [NFPROTO_BRIDGE] = "eb", 69 [NFPROTO_IPV6] = "ip6", 70 }; 71 72 /* Registration hooks for targets. */ 73 int xt_register_target(struct xt_target *target) 74 { 75 u_int8_t af = target->family; 76 77 mutex_lock(&xt[af].mutex); 78 list_add(&target->list, &xt[af].target); 79 mutex_unlock(&xt[af].mutex); 80 return 0; 81 } 82 EXPORT_SYMBOL(xt_register_target); 83 84 void 85 xt_unregister_target(struct xt_target *target) 86 { 87 u_int8_t af = target->family; 88 89 mutex_lock(&xt[af].mutex); 90 list_del(&target->list); 91 mutex_unlock(&xt[af].mutex); 92 } 93 EXPORT_SYMBOL(xt_unregister_target); 94 95 int 96 xt_register_targets(struct xt_target *target, unsigned int n) 97 { 98 unsigned int i; 99 int err = 0; 100 101 for (i = 0; i < n; i++) { 102 err = xt_register_target(&target[i]); 103 if (err) 104 goto err; 105 } 106 return err; 107 108 err: 109 if (i > 0) 110 xt_unregister_targets(target, i); 111 return err; 112 } 113 EXPORT_SYMBOL(xt_register_targets); 114 115 void 116 xt_unregister_targets(struct xt_target *target, unsigned int n) 117 { 118 while (n-- > 0) 119 xt_unregister_target(&target[n]); 120 } 121 EXPORT_SYMBOL(xt_unregister_targets); 122 123 int xt_register_match(struct xt_match *match) 124 { 125 u_int8_t af = match->family; 126 127 mutex_lock(&xt[af].mutex); 128 list_add(&match->list, &xt[af].match); 129 mutex_unlock(&xt[af].mutex); 130 return 0; 131 } 132 EXPORT_SYMBOL(xt_register_match); 133 134 void 135 xt_unregister_match(struct xt_match *match) 136 { 137 u_int8_t af = match->family; 138 139 mutex_lock(&xt[af].mutex); 140 list_del(&match->list); 141 mutex_unlock(&xt[af].mutex); 142 } 143 EXPORT_SYMBOL(xt_unregister_match); 144 145 int 146 xt_register_matches(struct xt_match *match, unsigned int n) 147 { 148 unsigned int i; 149 int err = 0; 150 151 for (i = 0; i < n; i++) { 152 err = xt_register_match(&match[i]); 153 if (err) 154 goto err; 155 } 156 return err; 157 158 err: 159 if (i > 0) 160 xt_unregister_matches(match, i); 161 return err; 162 } 163 EXPORT_SYMBOL(xt_register_matches); 164 165 void 166 xt_unregister_matches(struct xt_match *match, unsigned int n) 167 { 168 while (n-- > 0) 169 xt_unregister_match(&match[n]); 170 } 171 EXPORT_SYMBOL(xt_unregister_matches); 172 173 174 /* 175 * These are weird, but module loading must not be done with mutex 176 * held (since they will register), and we have to have a single 177 * function to use. 178 */ 179 180 /* Find match, grabs ref. Returns ERR_PTR() on error. */ 181 struct xt_match *xt_find_match(u8 af, const char *name, u8 revision) 182 { 183 struct xt_match *m; 184 int err = -ENOENT; 185 186 if (strnlen(name, XT_EXTENSION_MAXNAMELEN) == XT_EXTENSION_MAXNAMELEN) 187 return ERR_PTR(-EINVAL); 188 189 mutex_lock(&xt[af].mutex); 190 list_for_each_entry(m, &xt[af].match, list) { 191 if (strcmp(m->name, name) == 0) { 192 if (m->revision == revision) { 193 if (try_module_get(m->me)) { 194 mutex_unlock(&xt[af].mutex); 195 return m; 196 } 197 } else 198 err = -EPROTOTYPE; /* Found something. */ 199 } 200 } 201 mutex_unlock(&xt[af].mutex); 202 203 if (af != NFPROTO_UNSPEC) 204 /* Try searching again in the family-independent list */ 205 return xt_find_match(NFPROTO_UNSPEC, name, revision); 206 207 return ERR_PTR(err); 208 } 209 EXPORT_SYMBOL(xt_find_match); 210 211 struct xt_match * 212 xt_request_find_match(uint8_t nfproto, const char *name, uint8_t revision) 213 { 214 struct xt_match *match; 215 216 if (strnlen(name, XT_EXTENSION_MAXNAMELEN) == XT_EXTENSION_MAXNAMELEN) 217 return ERR_PTR(-EINVAL); 218 219 match = xt_find_match(nfproto, name, revision); 220 if (IS_ERR(match)) { 221 request_module("%st_%s", xt_prefix[nfproto], name); 222 match = xt_find_match(nfproto, name, revision); 223 } 224 225 return match; 226 } 227 EXPORT_SYMBOL_GPL(xt_request_find_match); 228 229 /* Find target, grabs ref. Returns ERR_PTR() on error. */ 230 struct xt_target *xt_find_target(u8 af, const char *name, u8 revision) 231 { 232 struct xt_target *t; 233 int err = -ENOENT; 234 235 if (strnlen(name, XT_EXTENSION_MAXNAMELEN) == XT_EXTENSION_MAXNAMELEN) 236 return ERR_PTR(-EINVAL); 237 238 mutex_lock(&xt[af].mutex); 239 list_for_each_entry(t, &xt[af].target, list) { 240 if (strcmp(t->name, name) == 0) { 241 if (t->revision == revision) { 242 if (try_module_get(t->me)) { 243 mutex_unlock(&xt[af].mutex); 244 return t; 245 } 246 } else 247 err = -EPROTOTYPE; /* Found something. */ 248 } 249 } 250 mutex_unlock(&xt[af].mutex); 251 252 if (af != NFPROTO_UNSPEC) 253 /* Try searching again in the family-independent list */ 254 return xt_find_target(NFPROTO_UNSPEC, name, revision); 255 256 return ERR_PTR(err); 257 } 258 EXPORT_SYMBOL(xt_find_target); 259 260 struct xt_target *xt_request_find_target(u8 af, const char *name, u8 revision) 261 { 262 struct xt_target *target; 263 264 if (strnlen(name, XT_EXTENSION_MAXNAMELEN) == XT_EXTENSION_MAXNAMELEN) 265 return ERR_PTR(-EINVAL); 266 267 target = xt_find_target(af, name, revision); 268 if (IS_ERR(target)) { 269 request_module("%st_%s", xt_prefix[af], name); 270 target = xt_find_target(af, name, revision); 271 } 272 273 return target; 274 } 275 EXPORT_SYMBOL_GPL(xt_request_find_target); 276 277 278 static int xt_obj_to_user(u16 __user *psize, u16 size, 279 void __user *pname, const char *name, 280 u8 __user *prev, u8 rev) 281 { 282 if (put_user(size, psize)) 283 return -EFAULT; 284 if (copy_to_user(pname, name, strlen(name) + 1)) 285 return -EFAULT; 286 if (put_user(rev, prev)) 287 return -EFAULT; 288 289 return 0; 290 } 291 292 #define XT_OBJ_TO_USER(U, K, TYPE, C_SIZE) \ 293 xt_obj_to_user(&U->u.TYPE##_size, C_SIZE ? : K->u.TYPE##_size, \ 294 U->u.user.name, K->u.kernel.TYPE->name, \ 295 &U->u.user.revision, K->u.kernel.TYPE->revision) 296 297 int xt_data_to_user(void __user *dst, const void *src, 298 int usersize, int size, int aligned_size) 299 { 300 usersize = usersize ? : size; 301 if (copy_to_user(dst, src, usersize)) 302 return -EFAULT; 303 if (usersize != aligned_size && 304 clear_user(dst + usersize, aligned_size - usersize)) 305 return -EFAULT; 306 307 return 0; 308 } 309 EXPORT_SYMBOL_GPL(xt_data_to_user); 310 311 #define XT_DATA_TO_USER(U, K, TYPE) \ 312 xt_data_to_user(U->data, K->data, \ 313 K->u.kernel.TYPE->usersize, \ 314 K->u.kernel.TYPE->TYPE##size, \ 315 XT_ALIGN(K->u.kernel.TYPE->TYPE##size)) 316 317 int xt_match_to_user(const struct xt_entry_match *m, 318 struct xt_entry_match __user *u) 319 { 320 return XT_OBJ_TO_USER(u, m, match, 0) || 321 XT_DATA_TO_USER(u, m, match); 322 } 323 EXPORT_SYMBOL_GPL(xt_match_to_user); 324 325 int xt_target_to_user(const struct xt_entry_target *t, 326 struct xt_entry_target __user *u) 327 { 328 return XT_OBJ_TO_USER(u, t, target, 0) || 329 XT_DATA_TO_USER(u, t, target); 330 } 331 EXPORT_SYMBOL_GPL(xt_target_to_user); 332 333 static int match_revfn(u8 af, const char *name, u8 revision, int *bestp) 334 { 335 const struct xt_match *m; 336 int have_rev = 0; 337 338 list_for_each_entry(m, &xt[af].match, list) { 339 if (strcmp(m->name, name) == 0) { 340 if (m->revision > *bestp) 341 *bestp = m->revision; 342 if (m->revision == revision) 343 have_rev = 1; 344 } 345 } 346 347 if (af != NFPROTO_UNSPEC && !have_rev) 348 return match_revfn(NFPROTO_UNSPEC, name, revision, bestp); 349 350 return have_rev; 351 } 352 353 static int target_revfn(u8 af, const char *name, u8 revision, int *bestp) 354 { 355 const struct xt_target *t; 356 int have_rev = 0; 357 358 list_for_each_entry(t, &xt[af].target, list) { 359 if (strcmp(t->name, name) == 0) { 360 if (t->revision > *bestp) 361 *bestp = t->revision; 362 if (t->revision == revision) 363 have_rev = 1; 364 } 365 } 366 367 if (af != NFPROTO_UNSPEC && !have_rev) 368 return target_revfn(NFPROTO_UNSPEC, name, revision, bestp); 369 370 return have_rev; 371 } 372 373 /* Returns true or false (if no such extension at all) */ 374 int xt_find_revision(u8 af, const char *name, u8 revision, int target, 375 int *err) 376 { 377 int have_rev, best = -1; 378 379 mutex_lock(&xt[af].mutex); 380 if (target == 1) 381 have_rev = target_revfn(af, name, revision, &best); 382 else 383 have_rev = match_revfn(af, name, revision, &best); 384 mutex_unlock(&xt[af].mutex); 385 386 /* Nothing at all? Return 0 to try loading module. */ 387 if (best == -1) { 388 *err = -ENOENT; 389 return 0; 390 } 391 392 *err = best; 393 if (!have_rev) 394 *err = -EPROTONOSUPPORT; 395 return 1; 396 } 397 EXPORT_SYMBOL_GPL(xt_find_revision); 398 399 static char * 400 textify_hooks(char *buf, size_t size, unsigned int mask, uint8_t nfproto) 401 { 402 static const char *const inetbr_names[] = { 403 "PREROUTING", "INPUT", "FORWARD", 404 "OUTPUT", "POSTROUTING", "BROUTING", 405 }; 406 static const char *const arp_names[] = { 407 "INPUT", "FORWARD", "OUTPUT", 408 }; 409 const char *const *names; 410 unsigned int i, max; 411 char *p = buf; 412 bool np = false; 413 int res; 414 415 names = (nfproto == NFPROTO_ARP) ? arp_names : inetbr_names; 416 max = (nfproto == NFPROTO_ARP) ? ARRAY_SIZE(arp_names) : 417 ARRAY_SIZE(inetbr_names); 418 *p = '\0'; 419 for (i = 0; i < max; ++i) { 420 if (!(mask & (1 << i))) 421 continue; 422 res = snprintf(p, size, "%s%s", np ? "/" : "", names[i]); 423 if (res > 0) { 424 size -= res; 425 p += res; 426 } 427 np = true; 428 } 429 430 return buf; 431 } 432 433 /** 434 * xt_check_proc_name - check that name is suitable for /proc file creation 435 * 436 * @name: file name candidate 437 * @size: length of buffer 438 * 439 * some x_tables modules wish to create a file in /proc. 440 * This function makes sure that the name is suitable for this 441 * purpose, it checks that name is NUL terminated and isn't a 'special' 442 * name, like "..". 443 * 444 * returns negative number on error or 0 if name is useable. 445 */ 446 int xt_check_proc_name(const char *name, unsigned int size) 447 { 448 if (name[0] == '\0') 449 return -EINVAL; 450 451 if (strnlen(name, size) == size) 452 return -ENAMETOOLONG; 453 454 if (strcmp(name, ".") == 0 || 455 strcmp(name, "..") == 0 || 456 strchr(name, '/')) 457 return -EINVAL; 458 459 return 0; 460 } 461 EXPORT_SYMBOL(xt_check_proc_name); 462 463 int xt_check_match(struct xt_mtchk_param *par, 464 unsigned int size, u_int8_t proto, bool inv_proto) 465 { 466 int ret; 467 468 if (XT_ALIGN(par->match->matchsize) != size && 469 par->match->matchsize != -1) { 470 /* 471 * ebt_among is exempt from centralized matchsize checking 472 * because it uses a dynamic-size data set. 473 */ 474 pr_err_ratelimited("%s_tables: %s.%u match: invalid size %u (kernel) != (user) %u\n", 475 xt_prefix[par->family], par->match->name, 476 par->match->revision, 477 XT_ALIGN(par->match->matchsize), size); 478 return -EINVAL; 479 } 480 if (par->match->table != NULL && 481 strcmp(par->match->table, par->table) != 0) { 482 pr_info_ratelimited("%s_tables: %s match: only valid in %s table, not %s\n", 483 xt_prefix[par->family], par->match->name, 484 par->match->table, par->table); 485 return -EINVAL; 486 } 487 if (par->match->hooks && (par->hook_mask & ~par->match->hooks) != 0) { 488 char used[64], allow[64]; 489 490 pr_info_ratelimited("%s_tables: %s match: used from hooks %s, but only valid from %s\n", 491 xt_prefix[par->family], par->match->name, 492 textify_hooks(used, sizeof(used), 493 par->hook_mask, par->family), 494 textify_hooks(allow, sizeof(allow), 495 par->match->hooks, 496 par->family)); 497 return -EINVAL; 498 } 499 if (par->match->proto && (par->match->proto != proto || inv_proto)) { 500 pr_info_ratelimited("%s_tables: %s match: only valid for protocol %u\n", 501 xt_prefix[par->family], par->match->name, 502 par->match->proto); 503 return -EINVAL; 504 } 505 if (par->match->checkentry != NULL) { 506 ret = par->match->checkentry(par); 507 if (ret < 0) 508 return ret; 509 else if (ret > 0) 510 /* Flag up potential errors. */ 511 return -EIO; 512 } 513 return 0; 514 } 515 EXPORT_SYMBOL_GPL(xt_check_match); 516 517 /** xt_check_entry_match - check that matches end before start of target 518 * 519 * @match: beginning of xt_entry_match 520 * @target: beginning of this rules target (alleged end of matches) 521 * @alignment: alignment requirement of match structures 522 * 523 * Validates that all matches add up to the beginning of the target, 524 * and that each match covers at least the base structure size. 525 * 526 * Return: 0 on success, negative errno on failure. 527 */ 528 static int xt_check_entry_match(const char *match, const char *target, 529 const size_t alignment) 530 { 531 const struct xt_entry_match *pos; 532 int length = target - match; 533 534 if (length == 0) /* no matches */ 535 return 0; 536 537 pos = (struct xt_entry_match *)match; 538 do { 539 if ((unsigned long)pos % alignment) 540 return -EINVAL; 541 542 if (length < (int)sizeof(struct xt_entry_match)) 543 return -EINVAL; 544 545 if (pos->u.match_size < sizeof(struct xt_entry_match)) 546 return -EINVAL; 547 548 if (pos->u.match_size > length) 549 return -EINVAL; 550 551 length -= pos->u.match_size; 552 pos = ((void *)((char *)(pos) + (pos)->u.match_size)); 553 } while (length > 0); 554 555 return 0; 556 } 557 558 /** xt_check_table_hooks - check hook entry points are sane 559 * 560 * @info xt_table_info to check 561 * @valid_hooks - hook entry points that we can enter from 562 * 563 * Validates that the hook entry and underflows points are set up. 564 * 565 * Return: 0 on success, negative errno on failure. 566 */ 567 int xt_check_table_hooks(const struct xt_table_info *info, unsigned int valid_hooks) 568 { 569 const char *err = "unsorted underflow"; 570 unsigned int i, max_uflow, max_entry; 571 bool check_hooks = false; 572 573 BUILD_BUG_ON(ARRAY_SIZE(info->hook_entry) != ARRAY_SIZE(info->underflow)); 574 575 max_entry = 0; 576 max_uflow = 0; 577 578 for (i = 0; i < ARRAY_SIZE(info->hook_entry); i++) { 579 if (!(valid_hooks & (1 << i))) 580 continue; 581 582 if (info->hook_entry[i] == 0xFFFFFFFF) 583 return -EINVAL; 584 if (info->underflow[i] == 0xFFFFFFFF) 585 return -EINVAL; 586 587 if (check_hooks) { 588 if (max_uflow > info->underflow[i]) 589 goto error; 590 591 if (max_uflow == info->underflow[i]) { 592 err = "duplicate underflow"; 593 goto error; 594 } 595 if (max_entry > info->hook_entry[i]) { 596 err = "unsorted entry"; 597 goto error; 598 } 599 if (max_entry == info->hook_entry[i]) { 600 err = "duplicate entry"; 601 goto error; 602 } 603 } 604 max_entry = info->hook_entry[i]; 605 max_uflow = info->underflow[i]; 606 check_hooks = true; 607 } 608 609 return 0; 610 error: 611 pr_err_ratelimited("%s at hook %d\n", err, i); 612 return -EINVAL; 613 } 614 EXPORT_SYMBOL(xt_check_table_hooks); 615 616 static bool verdict_ok(int verdict) 617 { 618 if (verdict > 0) 619 return true; 620 621 if (verdict < 0) { 622 int v = -verdict - 1; 623 624 if (verdict == XT_RETURN) 625 return true; 626 627 switch (v) { 628 case NF_ACCEPT: return true; 629 case NF_DROP: return true; 630 case NF_QUEUE: return true; 631 default: 632 break; 633 } 634 635 return false; 636 } 637 638 return false; 639 } 640 641 static bool error_tg_ok(unsigned int usersize, unsigned int kernsize, 642 const char *msg, unsigned int msglen) 643 { 644 return usersize == kernsize && strnlen(msg, msglen) < msglen; 645 } 646 647 #ifdef CONFIG_COMPAT 648 int xt_compat_add_offset(u_int8_t af, unsigned int offset, int delta) 649 { 650 struct xt_af *xp = &xt[af]; 651 652 WARN_ON(!mutex_is_locked(&xt[af].compat_mutex)); 653 654 if (WARN_ON(!xp->compat_tab)) 655 return -ENOMEM; 656 657 if (xp->cur >= xp->number) 658 return -EINVAL; 659 660 if (xp->cur) 661 delta += xp->compat_tab[xp->cur - 1].delta; 662 xp->compat_tab[xp->cur].offset = offset; 663 xp->compat_tab[xp->cur].delta = delta; 664 xp->cur++; 665 return 0; 666 } 667 EXPORT_SYMBOL_GPL(xt_compat_add_offset); 668 669 void xt_compat_flush_offsets(u_int8_t af) 670 { 671 WARN_ON(!mutex_is_locked(&xt[af].compat_mutex)); 672 673 if (xt[af].compat_tab) { 674 vfree(xt[af].compat_tab); 675 xt[af].compat_tab = NULL; 676 xt[af].number = 0; 677 xt[af].cur = 0; 678 } 679 } 680 EXPORT_SYMBOL_GPL(xt_compat_flush_offsets); 681 682 int xt_compat_calc_jump(u_int8_t af, unsigned int offset) 683 { 684 struct compat_delta *tmp = xt[af].compat_tab; 685 int mid, left = 0, right = xt[af].cur - 1; 686 687 while (left <= right) { 688 mid = (left + right) >> 1; 689 if (offset > tmp[mid].offset) 690 left = mid + 1; 691 else if (offset < tmp[mid].offset) 692 right = mid - 1; 693 else 694 return mid ? tmp[mid - 1].delta : 0; 695 } 696 return left ? tmp[left - 1].delta : 0; 697 } 698 EXPORT_SYMBOL_GPL(xt_compat_calc_jump); 699 700 int xt_compat_init_offsets(u8 af, unsigned int number) 701 { 702 size_t mem; 703 704 WARN_ON(!mutex_is_locked(&xt[af].compat_mutex)); 705 706 if (!number || number > (INT_MAX / sizeof(struct compat_delta))) 707 return -EINVAL; 708 709 if (WARN_ON(xt[af].compat_tab)) 710 return -EINVAL; 711 712 mem = sizeof(struct compat_delta) * number; 713 if (mem > XT_MAX_TABLE_SIZE) 714 return -ENOMEM; 715 716 xt[af].compat_tab = vmalloc(mem); 717 if (!xt[af].compat_tab) 718 return -ENOMEM; 719 720 xt[af].number = number; 721 xt[af].cur = 0; 722 723 return 0; 724 } 725 EXPORT_SYMBOL(xt_compat_init_offsets); 726 727 int xt_compat_match_offset(const struct xt_match *match) 728 { 729 u_int16_t csize = match->compatsize ? : match->matchsize; 730 return XT_ALIGN(match->matchsize) - COMPAT_XT_ALIGN(csize); 731 } 732 EXPORT_SYMBOL_GPL(xt_compat_match_offset); 733 734 void xt_compat_match_from_user(struct xt_entry_match *m, void **dstptr, 735 unsigned int *size) 736 { 737 const struct xt_match *match = m->u.kernel.match; 738 struct compat_xt_entry_match *cm = (struct compat_xt_entry_match *)m; 739 int pad, off = xt_compat_match_offset(match); 740 u_int16_t msize = cm->u.user.match_size; 741 char name[sizeof(m->u.user.name)]; 742 743 m = *dstptr; 744 memcpy(m, cm, sizeof(*cm)); 745 if (match->compat_from_user) 746 match->compat_from_user(m->data, cm->data); 747 else 748 memcpy(m->data, cm->data, msize - sizeof(*cm)); 749 pad = XT_ALIGN(match->matchsize) - match->matchsize; 750 if (pad > 0) 751 memset(m->data + match->matchsize, 0, pad); 752 753 msize += off; 754 m->u.user.match_size = msize; 755 strlcpy(name, match->name, sizeof(name)); 756 module_put(match->me); 757 strncpy(m->u.user.name, name, sizeof(m->u.user.name)); 758 759 *size += off; 760 *dstptr += msize; 761 } 762 EXPORT_SYMBOL_GPL(xt_compat_match_from_user); 763 764 #define COMPAT_XT_DATA_TO_USER(U, K, TYPE, C_SIZE) \ 765 xt_data_to_user(U->data, K->data, \ 766 K->u.kernel.TYPE->usersize, \ 767 C_SIZE, \ 768 COMPAT_XT_ALIGN(C_SIZE)) 769 770 int xt_compat_match_to_user(const struct xt_entry_match *m, 771 void __user **dstptr, unsigned int *size) 772 { 773 const struct xt_match *match = m->u.kernel.match; 774 struct compat_xt_entry_match __user *cm = *dstptr; 775 int off = xt_compat_match_offset(match); 776 u_int16_t msize = m->u.user.match_size - off; 777 778 if (XT_OBJ_TO_USER(cm, m, match, msize)) 779 return -EFAULT; 780 781 if (match->compat_to_user) { 782 if (match->compat_to_user((void __user *)cm->data, m->data)) 783 return -EFAULT; 784 } else { 785 if (COMPAT_XT_DATA_TO_USER(cm, m, match, msize - sizeof(*cm))) 786 return -EFAULT; 787 } 788 789 *size -= off; 790 *dstptr += msize; 791 return 0; 792 } 793 EXPORT_SYMBOL_GPL(xt_compat_match_to_user); 794 795 /* non-compat version may have padding after verdict */ 796 struct compat_xt_standard_target { 797 struct compat_xt_entry_target t; 798 compat_uint_t verdict; 799 }; 800 801 struct compat_xt_error_target { 802 struct compat_xt_entry_target t; 803 char errorname[XT_FUNCTION_MAXNAMELEN]; 804 }; 805 806 int xt_compat_check_entry_offsets(const void *base, const char *elems, 807 unsigned int target_offset, 808 unsigned int next_offset) 809 { 810 long size_of_base_struct = elems - (const char *)base; 811 const struct compat_xt_entry_target *t; 812 const char *e = base; 813 814 if (target_offset < size_of_base_struct) 815 return -EINVAL; 816 817 if (target_offset + sizeof(*t) > next_offset) 818 return -EINVAL; 819 820 t = (void *)(e + target_offset); 821 if (t->u.target_size < sizeof(*t)) 822 return -EINVAL; 823 824 if (target_offset + t->u.target_size > next_offset) 825 return -EINVAL; 826 827 if (strcmp(t->u.user.name, XT_STANDARD_TARGET) == 0) { 828 const struct compat_xt_standard_target *st = (const void *)t; 829 830 if (COMPAT_XT_ALIGN(target_offset + sizeof(*st)) != next_offset) 831 return -EINVAL; 832 833 if (!verdict_ok(st->verdict)) 834 return -EINVAL; 835 } else if (strcmp(t->u.user.name, XT_ERROR_TARGET) == 0) { 836 const struct compat_xt_error_target *et = (const void *)t; 837 838 if (!error_tg_ok(t->u.target_size, sizeof(*et), 839 et->errorname, sizeof(et->errorname))) 840 return -EINVAL; 841 } 842 843 /* compat_xt_entry match has less strict alignment requirements, 844 * otherwise they are identical. In case of padding differences 845 * we need to add compat version of xt_check_entry_match. 846 */ 847 BUILD_BUG_ON(sizeof(struct compat_xt_entry_match) != sizeof(struct xt_entry_match)); 848 849 return xt_check_entry_match(elems, base + target_offset, 850 __alignof__(struct compat_xt_entry_match)); 851 } 852 EXPORT_SYMBOL(xt_compat_check_entry_offsets); 853 #endif /* CONFIG_COMPAT */ 854 855 /** 856 * xt_check_entry_offsets - validate arp/ip/ip6t_entry 857 * 858 * @base: pointer to arp/ip/ip6t_entry 859 * @elems: pointer to first xt_entry_match, i.e. ip(6)t_entry->elems 860 * @target_offset: the arp/ip/ip6_t->target_offset 861 * @next_offset: the arp/ip/ip6_t->next_offset 862 * 863 * validates that target_offset and next_offset are sane and that all 864 * match sizes (if any) align with the target offset. 865 * 866 * This function does not validate the targets or matches themselves, it 867 * only tests that all the offsets and sizes are correct, that all 868 * match structures are aligned, and that the last structure ends where 869 * the target structure begins. 870 * 871 * Also see xt_compat_check_entry_offsets for CONFIG_COMPAT version. 872 * 873 * The arp/ip/ip6t_entry structure @base must have passed following tests: 874 * - it must point to a valid memory location 875 * - base to base + next_offset must be accessible, i.e. not exceed allocated 876 * length. 877 * 878 * A well-formed entry looks like this: 879 * 880 * ip(6)t_entry match [mtdata] match [mtdata] target [tgdata] ip(6)t_entry 881 * e->elems[]-----' | | 882 * matchsize | | 883 * matchsize | | 884 * | | 885 * target_offset---------------------------------' | 886 * next_offset---------------------------------------------------' 887 * 888 * elems[]: flexible array member at end of ip(6)/arpt_entry struct. 889 * This is where matches (if any) and the target reside. 890 * target_offset: beginning of target. 891 * next_offset: start of the next rule; also: size of this rule. 892 * Since targets have a minimum size, target_offset + minlen <= next_offset. 893 * 894 * Every match stores its size, sum of sizes must not exceed target_offset. 895 * 896 * Return: 0 on success, negative errno on failure. 897 */ 898 int xt_check_entry_offsets(const void *base, 899 const char *elems, 900 unsigned int target_offset, 901 unsigned int next_offset) 902 { 903 long size_of_base_struct = elems - (const char *)base; 904 const struct xt_entry_target *t; 905 const char *e = base; 906 907 /* target start is within the ip/ip6/arpt_entry struct */ 908 if (target_offset < size_of_base_struct) 909 return -EINVAL; 910 911 if (target_offset + sizeof(*t) > next_offset) 912 return -EINVAL; 913 914 t = (void *)(e + target_offset); 915 if (t->u.target_size < sizeof(*t)) 916 return -EINVAL; 917 918 if (target_offset + t->u.target_size > next_offset) 919 return -EINVAL; 920 921 if (strcmp(t->u.user.name, XT_STANDARD_TARGET) == 0) { 922 const struct xt_standard_target *st = (const void *)t; 923 924 if (XT_ALIGN(target_offset + sizeof(*st)) != next_offset) 925 return -EINVAL; 926 927 if (!verdict_ok(st->verdict)) 928 return -EINVAL; 929 } else if (strcmp(t->u.user.name, XT_ERROR_TARGET) == 0) { 930 const struct xt_error_target *et = (const void *)t; 931 932 if (!error_tg_ok(t->u.target_size, sizeof(*et), 933 et->errorname, sizeof(et->errorname))) 934 return -EINVAL; 935 } 936 937 return xt_check_entry_match(elems, base + target_offset, 938 __alignof__(struct xt_entry_match)); 939 } 940 EXPORT_SYMBOL(xt_check_entry_offsets); 941 942 /** 943 * xt_alloc_entry_offsets - allocate array to store rule head offsets 944 * 945 * @size: number of entries 946 * 947 * Return: NULL or kmalloc'd or vmalloc'd array 948 */ 949 unsigned int *xt_alloc_entry_offsets(unsigned int size) 950 { 951 if (size > XT_MAX_TABLE_SIZE / sizeof(unsigned int)) 952 return NULL; 953 954 return kvmalloc_array(size, sizeof(unsigned int), GFP_KERNEL | __GFP_ZERO); 955 956 } 957 EXPORT_SYMBOL(xt_alloc_entry_offsets); 958 959 /** 960 * xt_find_jump_offset - check if target is a valid jump offset 961 * 962 * @offsets: array containing all valid rule start offsets of a rule blob 963 * @target: the jump target to search for 964 * @size: entries in @offset 965 */ 966 bool xt_find_jump_offset(const unsigned int *offsets, 967 unsigned int target, unsigned int size) 968 { 969 int m, low = 0, hi = size; 970 971 while (hi > low) { 972 m = (low + hi) / 2u; 973 974 if (offsets[m] > target) 975 hi = m; 976 else if (offsets[m] < target) 977 low = m + 1; 978 else 979 return true; 980 } 981 982 return false; 983 } 984 EXPORT_SYMBOL(xt_find_jump_offset); 985 986 int xt_check_target(struct xt_tgchk_param *par, 987 unsigned int size, u_int8_t proto, bool inv_proto) 988 { 989 int ret; 990 991 if (XT_ALIGN(par->target->targetsize) != size) { 992 pr_err_ratelimited("%s_tables: %s.%u target: invalid size %u (kernel) != (user) %u\n", 993 xt_prefix[par->family], par->target->name, 994 par->target->revision, 995 XT_ALIGN(par->target->targetsize), size); 996 return -EINVAL; 997 } 998 if (par->target->table != NULL && 999 strcmp(par->target->table, par->table) != 0) { 1000 pr_info_ratelimited("%s_tables: %s target: only valid in %s table, not %s\n", 1001 xt_prefix[par->family], par->target->name, 1002 par->target->table, par->table); 1003 return -EINVAL; 1004 } 1005 if (par->target->hooks && (par->hook_mask & ~par->target->hooks) != 0) { 1006 char used[64], allow[64]; 1007 1008 pr_info_ratelimited("%s_tables: %s target: used from hooks %s, but only usable from %s\n", 1009 xt_prefix[par->family], par->target->name, 1010 textify_hooks(used, sizeof(used), 1011 par->hook_mask, par->family), 1012 textify_hooks(allow, sizeof(allow), 1013 par->target->hooks, 1014 par->family)); 1015 return -EINVAL; 1016 } 1017 if (par->target->proto && (par->target->proto != proto || inv_proto)) { 1018 pr_info_ratelimited("%s_tables: %s target: only valid for protocol %u\n", 1019 xt_prefix[par->family], par->target->name, 1020 par->target->proto); 1021 return -EINVAL; 1022 } 1023 if (par->target->checkentry != NULL) { 1024 ret = par->target->checkentry(par); 1025 if (ret < 0) 1026 return ret; 1027 else if (ret > 0) 1028 /* Flag up potential errors. */ 1029 return -EIO; 1030 } 1031 return 0; 1032 } 1033 EXPORT_SYMBOL_GPL(xt_check_target); 1034 1035 /** 1036 * xt_copy_counters_from_user - copy counters and metadata from userspace 1037 * 1038 * @user: src pointer to userspace memory 1039 * @len: alleged size of userspace memory 1040 * @info: where to store the xt_counters_info metadata 1041 * @compat: true if we setsockopt call is done by 32bit task on 64bit kernel 1042 * 1043 * Copies counter meta data from @user and stores it in @info. 1044 * 1045 * vmallocs memory to hold the counters, then copies the counter data 1046 * from @user to the new memory and returns a pointer to it. 1047 * 1048 * If @compat is true, @info gets converted automatically to the 64bit 1049 * representation. 1050 * 1051 * The metadata associated with the counters is stored in @info. 1052 * 1053 * Return: returns pointer that caller has to test via IS_ERR(). 1054 * If IS_ERR is false, caller has to vfree the pointer. 1055 */ 1056 void *xt_copy_counters_from_user(const void __user *user, unsigned int len, 1057 struct xt_counters_info *info, bool compat) 1058 { 1059 void *mem; 1060 u64 size; 1061 1062 #ifdef CONFIG_COMPAT 1063 if (compat) { 1064 /* structures only differ in size due to alignment */ 1065 struct compat_xt_counters_info compat_tmp; 1066 1067 if (len <= sizeof(compat_tmp)) 1068 return ERR_PTR(-EINVAL); 1069 1070 len -= sizeof(compat_tmp); 1071 if (copy_from_user(&compat_tmp, user, sizeof(compat_tmp)) != 0) 1072 return ERR_PTR(-EFAULT); 1073 1074 memcpy(info->name, compat_tmp.name, sizeof(info->name) - 1); 1075 info->num_counters = compat_tmp.num_counters; 1076 user += sizeof(compat_tmp); 1077 } else 1078 #endif 1079 { 1080 if (len <= sizeof(*info)) 1081 return ERR_PTR(-EINVAL); 1082 1083 len -= sizeof(*info); 1084 if (copy_from_user(info, user, sizeof(*info)) != 0) 1085 return ERR_PTR(-EFAULT); 1086 1087 user += sizeof(*info); 1088 } 1089 info->name[sizeof(info->name) - 1] = '\0'; 1090 1091 size = sizeof(struct xt_counters); 1092 size *= info->num_counters; 1093 1094 if (size != (u64)len) 1095 return ERR_PTR(-EINVAL); 1096 1097 mem = vmalloc(len); 1098 if (!mem) 1099 return ERR_PTR(-ENOMEM); 1100 1101 if (copy_from_user(mem, user, len) == 0) 1102 return mem; 1103 1104 vfree(mem); 1105 return ERR_PTR(-EFAULT); 1106 } 1107 EXPORT_SYMBOL_GPL(xt_copy_counters_from_user); 1108 1109 #ifdef CONFIG_COMPAT 1110 int xt_compat_target_offset(const struct xt_target *target) 1111 { 1112 u_int16_t csize = target->compatsize ? : target->targetsize; 1113 return XT_ALIGN(target->targetsize) - COMPAT_XT_ALIGN(csize); 1114 } 1115 EXPORT_SYMBOL_GPL(xt_compat_target_offset); 1116 1117 void xt_compat_target_from_user(struct xt_entry_target *t, void **dstptr, 1118 unsigned int *size) 1119 { 1120 const struct xt_target *target = t->u.kernel.target; 1121 struct compat_xt_entry_target *ct = (struct compat_xt_entry_target *)t; 1122 int pad, off = xt_compat_target_offset(target); 1123 u_int16_t tsize = ct->u.user.target_size; 1124 char name[sizeof(t->u.user.name)]; 1125 1126 t = *dstptr; 1127 memcpy(t, ct, sizeof(*ct)); 1128 if (target->compat_from_user) 1129 target->compat_from_user(t->data, ct->data); 1130 else 1131 memcpy(t->data, ct->data, tsize - sizeof(*ct)); 1132 pad = XT_ALIGN(target->targetsize) - target->targetsize; 1133 if (pad > 0) 1134 memset(t->data + target->targetsize, 0, pad); 1135 1136 tsize += off; 1137 t->u.user.target_size = tsize; 1138 strlcpy(name, target->name, sizeof(name)); 1139 module_put(target->me); 1140 strncpy(t->u.user.name, name, sizeof(t->u.user.name)); 1141 1142 *size += off; 1143 *dstptr += tsize; 1144 } 1145 EXPORT_SYMBOL_GPL(xt_compat_target_from_user); 1146 1147 int xt_compat_target_to_user(const struct xt_entry_target *t, 1148 void __user **dstptr, unsigned int *size) 1149 { 1150 const struct xt_target *target = t->u.kernel.target; 1151 struct compat_xt_entry_target __user *ct = *dstptr; 1152 int off = xt_compat_target_offset(target); 1153 u_int16_t tsize = t->u.user.target_size - off; 1154 1155 if (XT_OBJ_TO_USER(ct, t, target, tsize)) 1156 return -EFAULT; 1157 1158 if (target->compat_to_user) { 1159 if (target->compat_to_user((void __user *)ct->data, t->data)) 1160 return -EFAULT; 1161 } else { 1162 if (COMPAT_XT_DATA_TO_USER(ct, t, target, tsize - sizeof(*ct))) 1163 return -EFAULT; 1164 } 1165 1166 *size -= off; 1167 *dstptr += tsize; 1168 return 0; 1169 } 1170 EXPORT_SYMBOL_GPL(xt_compat_target_to_user); 1171 #endif 1172 1173 struct xt_table_info *xt_alloc_table_info(unsigned int size) 1174 { 1175 struct xt_table_info *info = NULL; 1176 size_t sz = sizeof(*info) + size; 1177 1178 if (sz < sizeof(*info) || sz >= XT_MAX_TABLE_SIZE) 1179 return NULL; 1180 1181 /* __GFP_NORETRY is not fully supported by kvmalloc but it should 1182 * work reasonably well if sz is too large and bail out rather 1183 * than shoot all processes down before realizing there is nothing 1184 * more to reclaim. 1185 */ 1186 info = kvmalloc(sz, GFP_KERNEL | __GFP_NORETRY); 1187 if (!info) 1188 return NULL; 1189 1190 memset(info, 0, sizeof(*info)); 1191 info->size = size; 1192 return info; 1193 } 1194 EXPORT_SYMBOL(xt_alloc_table_info); 1195 1196 void xt_free_table_info(struct xt_table_info *info) 1197 { 1198 int cpu; 1199 1200 if (info->jumpstack != NULL) { 1201 for_each_possible_cpu(cpu) 1202 kvfree(info->jumpstack[cpu]); 1203 kvfree(info->jumpstack); 1204 } 1205 1206 kvfree(info); 1207 } 1208 EXPORT_SYMBOL(xt_free_table_info); 1209 1210 /* Find table by name, grabs mutex & ref. Returns ERR_PTR on error. */ 1211 struct xt_table *xt_find_table_lock(struct net *net, u_int8_t af, 1212 const char *name) 1213 { 1214 struct xt_table *t, *found = NULL; 1215 1216 mutex_lock(&xt[af].mutex); 1217 list_for_each_entry(t, &net->xt.tables[af], list) 1218 if (strcmp(t->name, name) == 0 && try_module_get(t->me)) 1219 return t; 1220 1221 if (net == &init_net) 1222 goto out; 1223 1224 /* Table doesn't exist in this netns, re-try init */ 1225 list_for_each_entry(t, &init_net.xt.tables[af], list) { 1226 int err; 1227 1228 if (strcmp(t->name, name)) 1229 continue; 1230 if (!try_module_get(t->me)) 1231 goto out; 1232 mutex_unlock(&xt[af].mutex); 1233 err = t->table_init(net); 1234 if (err < 0) { 1235 module_put(t->me); 1236 return ERR_PTR(err); 1237 } 1238 1239 found = t; 1240 1241 mutex_lock(&xt[af].mutex); 1242 break; 1243 } 1244 1245 if (!found) 1246 goto out; 1247 1248 /* and once again: */ 1249 list_for_each_entry(t, &net->xt.tables[af], list) 1250 if (strcmp(t->name, name) == 0) 1251 return t; 1252 1253 module_put(found->me); 1254 out: 1255 mutex_unlock(&xt[af].mutex); 1256 return ERR_PTR(-ENOENT); 1257 } 1258 EXPORT_SYMBOL_GPL(xt_find_table_lock); 1259 1260 struct xt_table *xt_request_find_table_lock(struct net *net, u_int8_t af, 1261 const char *name) 1262 { 1263 struct xt_table *t = xt_find_table_lock(net, af, name); 1264 1265 #ifdef CONFIG_MODULES 1266 if (IS_ERR(t)) { 1267 int err = request_module("%stable_%s", xt_prefix[af], name); 1268 if (err < 0) 1269 return ERR_PTR(err); 1270 t = xt_find_table_lock(net, af, name); 1271 } 1272 #endif 1273 1274 return t; 1275 } 1276 EXPORT_SYMBOL_GPL(xt_request_find_table_lock); 1277 1278 void xt_table_unlock(struct xt_table *table) 1279 { 1280 mutex_unlock(&xt[table->af].mutex); 1281 } 1282 EXPORT_SYMBOL_GPL(xt_table_unlock); 1283 1284 #ifdef CONFIG_COMPAT 1285 void xt_compat_lock(u_int8_t af) 1286 { 1287 mutex_lock(&xt[af].compat_mutex); 1288 } 1289 EXPORT_SYMBOL_GPL(xt_compat_lock); 1290 1291 void xt_compat_unlock(u_int8_t af) 1292 { 1293 mutex_unlock(&xt[af].compat_mutex); 1294 } 1295 EXPORT_SYMBOL_GPL(xt_compat_unlock); 1296 #endif 1297 1298 DEFINE_PER_CPU(seqcount_t, xt_recseq); 1299 EXPORT_PER_CPU_SYMBOL_GPL(xt_recseq); 1300 1301 struct static_key xt_tee_enabled __read_mostly; 1302 EXPORT_SYMBOL_GPL(xt_tee_enabled); 1303 1304 static int xt_jumpstack_alloc(struct xt_table_info *i) 1305 { 1306 unsigned int size; 1307 int cpu; 1308 1309 size = sizeof(void **) * nr_cpu_ids; 1310 if (size > PAGE_SIZE) 1311 i->jumpstack = kvzalloc(size, GFP_KERNEL); 1312 else 1313 i->jumpstack = kzalloc(size, GFP_KERNEL); 1314 if (i->jumpstack == NULL) 1315 return -ENOMEM; 1316 1317 /* ruleset without jumps -- no stack needed */ 1318 if (i->stacksize == 0) 1319 return 0; 1320 1321 /* Jumpstack needs to be able to record two full callchains, one 1322 * from the first rule set traversal, plus one table reentrancy 1323 * via -j TEE without clobbering the callchain that brought us to 1324 * TEE target. 1325 * 1326 * This is done by allocating two jumpstacks per cpu, on reentry 1327 * the upper half of the stack is used. 1328 * 1329 * see the jumpstack setup in ipt_do_table() for more details. 1330 */ 1331 size = sizeof(void *) * i->stacksize * 2u; 1332 for_each_possible_cpu(cpu) { 1333 i->jumpstack[cpu] = kvmalloc_node(size, GFP_KERNEL, 1334 cpu_to_node(cpu)); 1335 if (i->jumpstack[cpu] == NULL) 1336 /* 1337 * Freeing will be done later on by the callers. The 1338 * chain is: xt_replace_table -> __do_replace -> 1339 * do_replace -> xt_free_table_info. 1340 */ 1341 return -ENOMEM; 1342 } 1343 1344 return 0; 1345 } 1346 1347 struct xt_counters *xt_counters_alloc(unsigned int counters) 1348 { 1349 struct xt_counters *mem; 1350 1351 if (counters == 0 || counters > INT_MAX / sizeof(*mem)) 1352 return NULL; 1353 1354 counters *= sizeof(*mem); 1355 if (counters > XT_MAX_TABLE_SIZE) 1356 return NULL; 1357 1358 return vzalloc(counters); 1359 } 1360 EXPORT_SYMBOL(xt_counters_alloc); 1361 1362 struct xt_table_info * 1363 xt_replace_table(struct xt_table *table, 1364 unsigned int num_counters, 1365 struct xt_table_info *newinfo, 1366 int *error) 1367 { 1368 struct xt_table_info *private; 1369 unsigned int cpu; 1370 int ret; 1371 1372 ret = xt_jumpstack_alloc(newinfo); 1373 if (ret < 0) { 1374 *error = ret; 1375 return NULL; 1376 } 1377 1378 /* Do the substitution. */ 1379 local_bh_disable(); 1380 private = table->private; 1381 1382 /* Check inside lock: is the old number correct? */ 1383 if (num_counters != private->number) { 1384 pr_debug("num_counters != table->private->number (%u/%u)\n", 1385 num_counters, private->number); 1386 local_bh_enable(); 1387 *error = -EAGAIN; 1388 return NULL; 1389 } 1390 1391 newinfo->initial_entries = private->initial_entries; 1392 /* 1393 * Ensure contents of newinfo are visible before assigning to 1394 * private. 1395 */ 1396 smp_wmb(); 1397 table->private = newinfo; 1398 1399 /* make sure all cpus see new ->private value */ 1400 smp_wmb(); 1401 1402 /* 1403 * Even though table entries have now been swapped, other CPU's 1404 * may still be using the old entries... 1405 */ 1406 local_bh_enable(); 1407 1408 /* ... so wait for even xt_recseq on all cpus */ 1409 for_each_possible_cpu(cpu) { 1410 seqcount_t *s = &per_cpu(xt_recseq, cpu); 1411 u32 seq = raw_read_seqcount(s); 1412 1413 if (seq & 1) { 1414 do { 1415 cond_resched(); 1416 cpu_relax(); 1417 } while (seq == raw_read_seqcount(s)); 1418 } 1419 } 1420 1421 #ifdef CONFIG_AUDIT 1422 if (audit_enabled) { 1423 audit_log(audit_context(), GFP_KERNEL, 1424 AUDIT_NETFILTER_CFG, 1425 "table=%s family=%u entries=%u", 1426 table->name, table->af, private->number); 1427 } 1428 #endif 1429 1430 return private; 1431 } 1432 EXPORT_SYMBOL_GPL(xt_replace_table); 1433 1434 struct xt_table *xt_register_table(struct net *net, 1435 const struct xt_table *input_table, 1436 struct xt_table_info *bootstrap, 1437 struct xt_table_info *newinfo) 1438 { 1439 int ret; 1440 struct xt_table_info *private; 1441 struct xt_table *t, *table; 1442 1443 /* Don't add one object to multiple lists. */ 1444 table = kmemdup(input_table, sizeof(struct xt_table), GFP_KERNEL); 1445 if (!table) { 1446 ret = -ENOMEM; 1447 goto out; 1448 } 1449 1450 mutex_lock(&xt[table->af].mutex); 1451 /* Don't autoload: we'd eat our tail... */ 1452 list_for_each_entry(t, &net->xt.tables[table->af], list) { 1453 if (strcmp(t->name, table->name) == 0) { 1454 ret = -EEXIST; 1455 goto unlock; 1456 } 1457 } 1458 1459 /* Simplifies replace_table code. */ 1460 table->private = bootstrap; 1461 1462 if (!xt_replace_table(table, 0, newinfo, &ret)) 1463 goto unlock; 1464 1465 private = table->private; 1466 pr_debug("table->private->number = %u\n", private->number); 1467 1468 /* save number of initial entries */ 1469 private->initial_entries = private->number; 1470 1471 list_add(&table->list, &net->xt.tables[table->af]); 1472 mutex_unlock(&xt[table->af].mutex); 1473 return table; 1474 1475 unlock: 1476 mutex_unlock(&xt[table->af].mutex); 1477 kfree(table); 1478 out: 1479 return ERR_PTR(ret); 1480 } 1481 EXPORT_SYMBOL_GPL(xt_register_table); 1482 1483 void *xt_unregister_table(struct xt_table *table) 1484 { 1485 struct xt_table_info *private; 1486 1487 mutex_lock(&xt[table->af].mutex); 1488 private = table->private; 1489 list_del(&table->list); 1490 mutex_unlock(&xt[table->af].mutex); 1491 kfree(table); 1492 1493 return private; 1494 } 1495 EXPORT_SYMBOL_GPL(xt_unregister_table); 1496 1497 #ifdef CONFIG_PROC_FS 1498 static void *xt_table_seq_start(struct seq_file *seq, loff_t *pos) 1499 { 1500 struct net *net = seq_file_net(seq); 1501 u_int8_t af = (unsigned long)PDE_DATA(file_inode(seq->file)); 1502 1503 mutex_lock(&xt[af].mutex); 1504 return seq_list_start(&net->xt.tables[af], *pos); 1505 } 1506 1507 static void *xt_table_seq_next(struct seq_file *seq, void *v, loff_t *pos) 1508 { 1509 struct net *net = seq_file_net(seq); 1510 u_int8_t af = (unsigned long)PDE_DATA(file_inode(seq->file)); 1511 1512 return seq_list_next(v, &net->xt.tables[af], pos); 1513 } 1514 1515 static void xt_table_seq_stop(struct seq_file *seq, void *v) 1516 { 1517 u_int8_t af = (unsigned long)PDE_DATA(file_inode(seq->file)); 1518 1519 mutex_unlock(&xt[af].mutex); 1520 } 1521 1522 static int xt_table_seq_show(struct seq_file *seq, void *v) 1523 { 1524 struct xt_table *table = list_entry(v, struct xt_table, list); 1525 1526 if (*table->name) 1527 seq_printf(seq, "%s\n", table->name); 1528 return 0; 1529 } 1530 1531 static const struct seq_operations xt_table_seq_ops = { 1532 .start = xt_table_seq_start, 1533 .next = xt_table_seq_next, 1534 .stop = xt_table_seq_stop, 1535 .show = xt_table_seq_show, 1536 }; 1537 1538 /* 1539 * Traverse state for ip{,6}_{tables,matches} for helping crossing 1540 * the multi-AF mutexes. 1541 */ 1542 struct nf_mttg_trav { 1543 struct list_head *head, *curr; 1544 uint8_t class; 1545 }; 1546 1547 enum { 1548 MTTG_TRAV_INIT, 1549 MTTG_TRAV_NFP_UNSPEC, 1550 MTTG_TRAV_NFP_SPEC, 1551 MTTG_TRAV_DONE, 1552 }; 1553 1554 static void *xt_mttg_seq_next(struct seq_file *seq, void *v, loff_t *ppos, 1555 bool is_target) 1556 { 1557 static const uint8_t next_class[] = { 1558 [MTTG_TRAV_NFP_UNSPEC] = MTTG_TRAV_NFP_SPEC, 1559 [MTTG_TRAV_NFP_SPEC] = MTTG_TRAV_DONE, 1560 }; 1561 uint8_t nfproto = (unsigned long)PDE_DATA(file_inode(seq->file)); 1562 struct nf_mttg_trav *trav = seq->private; 1563 1564 switch (trav->class) { 1565 case MTTG_TRAV_INIT: 1566 trav->class = MTTG_TRAV_NFP_UNSPEC; 1567 mutex_lock(&xt[NFPROTO_UNSPEC].mutex); 1568 trav->head = trav->curr = is_target ? 1569 &xt[NFPROTO_UNSPEC].target : &xt[NFPROTO_UNSPEC].match; 1570 break; 1571 case MTTG_TRAV_NFP_UNSPEC: 1572 trav->curr = trav->curr->next; 1573 if (trav->curr != trav->head) 1574 break; 1575 mutex_unlock(&xt[NFPROTO_UNSPEC].mutex); 1576 mutex_lock(&xt[nfproto].mutex); 1577 trav->head = trav->curr = is_target ? 1578 &xt[nfproto].target : &xt[nfproto].match; 1579 trav->class = next_class[trav->class]; 1580 break; 1581 case MTTG_TRAV_NFP_SPEC: 1582 trav->curr = trav->curr->next; 1583 if (trav->curr != trav->head) 1584 break; 1585 /* fall through */ 1586 default: 1587 return NULL; 1588 } 1589 1590 if (ppos != NULL) 1591 ++*ppos; 1592 return trav; 1593 } 1594 1595 static void *xt_mttg_seq_start(struct seq_file *seq, loff_t *pos, 1596 bool is_target) 1597 { 1598 struct nf_mttg_trav *trav = seq->private; 1599 unsigned int j; 1600 1601 trav->class = MTTG_TRAV_INIT; 1602 for (j = 0; j < *pos; ++j) 1603 if (xt_mttg_seq_next(seq, NULL, NULL, is_target) == NULL) 1604 return NULL; 1605 return trav; 1606 } 1607 1608 static void xt_mttg_seq_stop(struct seq_file *seq, void *v) 1609 { 1610 uint8_t nfproto = (unsigned long)PDE_DATA(file_inode(seq->file)); 1611 struct nf_mttg_trav *trav = seq->private; 1612 1613 switch (trav->class) { 1614 case MTTG_TRAV_NFP_UNSPEC: 1615 mutex_unlock(&xt[NFPROTO_UNSPEC].mutex); 1616 break; 1617 case MTTG_TRAV_NFP_SPEC: 1618 mutex_unlock(&xt[nfproto].mutex); 1619 break; 1620 } 1621 } 1622 1623 static void *xt_match_seq_start(struct seq_file *seq, loff_t *pos) 1624 { 1625 return xt_mttg_seq_start(seq, pos, false); 1626 } 1627 1628 static void *xt_match_seq_next(struct seq_file *seq, void *v, loff_t *ppos) 1629 { 1630 return xt_mttg_seq_next(seq, v, ppos, false); 1631 } 1632 1633 static int xt_match_seq_show(struct seq_file *seq, void *v) 1634 { 1635 const struct nf_mttg_trav *trav = seq->private; 1636 const struct xt_match *match; 1637 1638 switch (trav->class) { 1639 case MTTG_TRAV_NFP_UNSPEC: 1640 case MTTG_TRAV_NFP_SPEC: 1641 if (trav->curr == trav->head) 1642 return 0; 1643 match = list_entry(trav->curr, struct xt_match, list); 1644 if (*match->name) 1645 seq_printf(seq, "%s\n", match->name); 1646 } 1647 return 0; 1648 } 1649 1650 static const struct seq_operations xt_match_seq_ops = { 1651 .start = xt_match_seq_start, 1652 .next = xt_match_seq_next, 1653 .stop = xt_mttg_seq_stop, 1654 .show = xt_match_seq_show, 1655 }; 1656 1657 static void *xt_target_seq_start(struct seq_file *seq, loff_t *pos) 1658 { 1659 return xt_mttg_seq_start(seq, pos, true); 1660 } 1661 1662 static void *xt_target_seq_next(struct seq_file *seq, void *v, loff_t *ppos) 1663 { 1664 return xt_mttg_seq_next(seq, v, ppos, true); 1665 } 1666 1667 static int xt_target_seq_show(struct seq_file *seq, void *v) 1668 { 1669 const struct nf_mttg_trav *trav = seq->private; 1670 const struct xt_target *target; 1671 1672 switch (trav->class) { 1673 case MTTG_TRAV_NFP_UNSPEC: 1674 case MTTG_TRAV_NFP_SPEC: 1675 if (trav->curr == trav->head) 1676 return 0; 1677 target = list_entry(trav->curr, struct xt_target, list); 1678 if (*target->name) 1679 seq_printf(seq, "%s\n", target->name); 1680 } 1681 return 0; 1682 } 1683 1684 static const struct seq_operations xt_target_seq_ops = { 1685 .start = xt_target_seq_start, 1686 .next = xt_target_seq_next, 1687 .stop = xt_mttg_seq_stop, 1688 .show = xt_target_seq_show, 1689 }; 1690 1691 #define FORMAT_TABLES "_tables_names" 1692 #define FORMAT_MATCHES "_tables_matches" 1693 #define FORMAT_TARGETS "_tables_targets" 1694 1695 #endif /* CONFIG_PROC_FS */ 1696 1697 /** 1698 * xt_hook_ops_alloc - set up hooks for a new table 1699 * @table: table with metadata needed to set up hooks 1700 * @fn: Hook function 1701 * 1702 * This function will create the nf_hook_ops that the x_table needs 1703 * to hand to xt_hook_link_net(). 1704 */ 1705 struct nf_hook_ops * 1706 xt_hook_ops_alloc(const struct xt_table *table, nf_hookfn *fn) 1707 { 1708 unsigned int hook_mask = table->valid_hooks; 1709 uint8_t i, num_hooks = hweight32(hook_mask); 1710 uint8_t hooknum; 1711 struct nf_hook_ops *ops; 1712 1713 if (!num_hooks) 1714 return ERR_PTR(-EINVAL); 1715 1716 ops = kcalloc(num_hooks, sizeof(*ops), GFP_KERNEL); 1717 if (ops == NULL) 1718 return ERR_PTR(-ENOMEM); 1719 1720 for (i = 0, hooknum = 0; i < num_hooks && hook_mask != 0; 1721 hook_mask >>= 1, ++hooknum) { 1722 if (!(hook_mask & 1)) 1723 continue; 1724 ops[i].hook = fn; 1725 ops[i].pf = table->af; 1726 ops[i].hooknum = hooknum; 1727 ops[i].priority = table->priority; 1728 ++i; 1729 } 1730 1731 return ops; 1732 } 1733 EXPORT_SYMBOL_GPL(xt_hook_ops_alloc); 1734 1735 int xt_proto_init(struct net *net, u_int8_t af) 1736 { 1737 #ifdef CONFIG_PROC_FS 1738 char buf[XT_FUNCTION_MAXNAMELEN]; 1739 struct proc_dir_entry *proc; 1740 kuid_t root_uid; 1741 kgid_t root_gid; 1742 #endif 1743 1744 if (af >= ARRAY_SIZE(xt_prefix)) 1745 return -EINVAL; 1746 1747 1748 #ifdef CONFIG_PROC_FS 1749 root_uid = make_kuid(net->user_ns, 0); 1750 root_gid = make_kgid(net->user_ns, 0); 1751 1752 strlcpy(buf, xt_prefix[af], sizeof(buf)); 1753 strlcat(buf, FORMAT_TABLES, sizeof(buf)); 1754 proc = proc_create_net_data(buf, 0440, net->proc_net, &xt_table_seq_ops, 1755 sizeof(struct seq_net_private), 1756 (void *)(unsigned long)af); 1757 if (!proc) 1758 goto out; 1759 if (uid_valid(root_uid) && gid_valid(root_gid)) 1760 proc_set_user(proc, root_uid, root_gid); 1761 1762 strlcpy(buf, xt_prefix[af], sizeof(buf)); 1763 strlcat(buf, FORMAT_MATCHES, sizeof(buf)); 1764 proc = proc_create_seq_private(buf, 0440, net->proc_net, 1765 &xt_match_seq_ops, sizeof(struct nf_mttg_trav), 1766 (void *)(unsigned long)af); 1767 if (!proc) 1768 goto out_remove_tables; 1769 if (uid_valid(root_uid) && gid_valid(root_gid)) 1770 proc_set_user(proc, root_uid, root_gid); 1771 1772 strlcpy(buf, xt_prefix[af], sizeof(buf)); 1773 strlcat(buf, FORMAT_TARGETS, sizeof(buf)); 1774 proc = proc_create_seq_private(buf, 0440, net->proc_net, 1775 &xt_target_seq_ops, sizeof(struct nf_mttg_trav), 1776 (void *)(unsigned long)af); 1777 if (!proc) 1778 goto out_remove_matches; 1779 if (uid_valid(root_uid) && gid_valid(root_gid)) 1780 proc_set_user(proc, root_uid, root_gid); 1781 #endif 1782 1783 return 0; 1784 1785 #ifdef CONFIG_PROC_FS 1786 out_remove_matches: 1787 strlcpy(buf, xt_prefix[af], sizeof(buf)); 1788 strlcat(buf, FORMAT_MATCHES, sizeof(buf)); 1789 remove_proc_entry(buf, net->proc_net); 1790 1791 out_remove_tables: 1792 strlcpy(buf, xt_prefix[af], sizeof(buf)); 1793 strlcat(buf, FORMAT_TABLES, sizeof(buf)); 1794 remove_proc_entry(buf, net->proc_net); 1795 out: 1796 return -1; 1797 #endif 1798 } 1799 EXPORT_SYMBOL_GPL(xt_proto_init); 1800 1801 void xt_proto_fini(struct net *net, u_int8_t af) 1802 { 1803 #ifdef CONFIG_PROC_FS 1804 char buf[XT_FUNCTION_MAXNAMELEN]; 1805 1806 strlcpy(buf, xt_prefix[af], sizeof(buf)); 1807 strlcat(buf, FORMAT_TABLES, sizeof(buf)); 1808 remove_proc_entry(buf, net->proc_net); 1809 1810 strlcpy(buf, xt_prefix[af], sizeof(buf)); 1811 strlcat(buf, FORMAT_TARGETS, sizeof(buf)); 1812 remove_proc_entry(buf, net->proc_net); 1813 1814 strlcpy(buf, xt_prefix[af], sizeof(buf)); 1815 strlcat(buf, FORMAT_MATCHES, sizeof(buf)); 1816 remove_proc_entry(buf, net->proc_net); 1817 #endif /*CONFIG_PROC_FS*/ 1818 } 1819 EXPORT_SYMBOL_GPL(xt_proto_fini); 1820 1821 /** 1822 * xt_percpu_counter_alloc - allocate x_tables rule counter 1823 * 1824 * @state: pointer to xt_percpu allocation state 1825 * @counter: pointer to counter struct inside the ip(6)/arpt_entry struct 1826 * 1827 * On SMP, the packet counter [ ip(6)t_entry->counters.pcnt ] will then 1828 * contain the address of the real (percpu) counter. 1829 * 1830 * Rule evaluation needs to use xt_get_this_cpu_counter() helper 1831 * to fetch the real percpu counter. 1832 * 1833 * To speed up allocation and improve data locality, a 4kb block is 1834 * allocated. Freeing any counter may free an entire block, so all 1835 * counters allocated using the same state must be freed at the same 1836 * time. 1837 * 1838 * xt_percpu_counter_alloc_state contains the base address of the 1839 * allocated page and the current sub-offset. 1840 * 1841 * returns false on error. 1842 */ 1843 bool xt_percpu_counter_alloc(struct xt_percpu_counter_alloc_state *state, 1844 struct xt_counters *counter) 1845 { 1846 BUILD_BUG_ON(XT_PCPU_BLOCK_SIZE < (sizeof(*counter) * 2)); 1847 1848 if (nr_cpu_ids <= 1) 1849 return true; 1850 1851 if (!state->mem) { 1852 state->mem = __alloc_percpu(XT_PCPU_BLOCK_SIZE, 1853 XT_PCPU_BLOCK_SIZE); 1854 if (!state->mem) 1855 return false; 1856 } 1857 counter->pcnt = (__force unsigned long)(state->mem + state->off); 1858 state->off += sizeof(*counter); 1859 if (state->off > (XT_PCPU_BLOCK_SIZE - sizeof(*counter))) { 1860 state->mem = NULL; 1861 state->off = 0; 1862 } 1863 return true; 1864 } 1865 EXPORT_SYMBOL_GPL(xt_percpu_counter_alloc); 1866 1867 void xt_percpu_counter_free(struct xt_counters *counters) 1868 { 1869 unsigned long pcnt = counters->pcnt; 1870 1871 if (nr_cpu_ids > 1 && (pcnt & (XT_PCPU_BLOCK_SIZE - 1)) == 0) 1872 free_percpu((void __percpu *)pcnt); 1873 } 1874 EXPORT_SYMBOL_GPL(xt_percpu_counter_free); 1875 1876 static int __net_init xt_net_init(struct net *net) 1877 { 1878 int i; 1879 1880 for (i = 0; i < NFPROTO_NUMPROTO; i++) 1881 INIT_LIST_HEAD(&net->xt.tables[i]); 1882 return 0; 1883 } 1884 1885 static void __net_exit xt_net_exit(struct net *net) 1886 { 1887 int i; 1888 1889 for (i = 0; i < NFPROTO_NUMPROTO; i++) 1890 WARN_ON_ONCE(!list_empty(&net->xt.tables[i])); 1891 } 1892 1893 static struct pernet_operations xt_net_ops = { 1894 .init = xt_net_init, 1895 .exit = xt_net_exit, 1896 }; 1897 1898 static int __init xt_init(void) 1899 { 1900 unsigned int i; 1901 int rv; 1902 1903 for_each_possible_cpu(i) { 1904 seqcount_init(&per_cpu(xt_recseq, i)); 1905 } 1906 1907 xt = kmalloc_array(NFPROTO_NUMPROTO, sizeof(struct xt_af), GFP_KERNEL); 1908 if (!xt) 1909 return -ENOMEM; 1910 1911 for (i = 0; i < NFPROTO_NUMPROTO; i++) { 1912 mutex_init(&xt[i].mutex); 1913 #ifdef CONFIG_COMPAT 1914 mutex_init(&xt[i].compat_mutex); 1915 xt[i].compat_tab = NULL; 1916 #endif 1917 INIT_LIST_HEAD(&xt[i].target); 1918 INIT_LIST_HEAD(&xt[i].match); 1919 } 1920 rv = register_pernet_subsys(&xt_net_ops); 1921 if (rv < 0) 1922 kfree(xt); 1923 return rv; 1924 } 1925 1926 static void __exit xt_fini(void) 1927 { 1928 unregister_pernet_subsys(&xt_net_ops); 1929 kfree(xt); 1930 } 1931 1932 module_init(xt_init); 1933 module_exit(xt_fini); 1934 1935