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