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