1 /* 2 * Packet matching code for ARP packets. 3 * 4 * Based heavily, if not almost entirely, upon ip_tables.c framework. 5 * 6 * Some ARP specific bits are: 7 * 8 * Copyright (C) 2002 David S. Miller (davem@redhat.com) 9 * Copyright (C) 2006-2009 Patrick McHardy <kaber@trash.net> 10 * 11 */ 12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 13 #include <linux/kernel.h> 14 #include <linux/skbuff.h> 15 #include <linux/netdevice.h> 16 #include <linux/capability.h> 17 #include <linux/if_arp.h> 18 #include <linux/kmod.h> 19 #include <linux/vmalloc.h> 20 #include <linux/proc_fs.h> 21 #include <linux/module.h> 22 #include <linux/init.h> 23 #include <linux/mutex.h> 24 #include <linux/err.h> 25 #include <net/compat.h> 26 #include <net/sock.h> 27 #include <linux/uaccess.h> 28 29 #include <linux/netfilter/x_tables.h> 30 #include <linux/netfilter_arp/arp_tables.h> 31 #include "../../netfilter/xt_repldata.h" 32 33 MODULE_LICENSE("GPL"); 34 MODULE_AUTHOR("David S. Miller <davem@redhat.com>"); 35 MODULE_DESCRIPTION("arptables core"); 36 37 void *arpt_alloc_initial_table(const struct xt_table *info) 38 { 39 return xt_alloc_initial_table(arpt, ARPT); 40 } 41 EXPORT_SYMBOL_GPL(arpt_alloc_initial_table); 42 43 static inline int arp_devaddr_compare(const struct arpt_devaddr_info *ap, 44 const char *hdr_addr, int len) 45 { 46 int i, ret; 47 48 if (len > ARPT_DEV_ADDR_LEN_MAX) 49 len = ARPT_DEV_ADDR_LEN_MAX; 50 51 ret = 0; 52 for (i = 0; i < len; i++) 53 ret |= (hdr_addr[i] ^ ap->addr[i]) & ap->mask[i]; 54 55 return ret != 0; 56 } 57 58 /* 59 * Unfortunately, _b and _mask are not aligned to an int (or long int) 60 * Some arches dont care, unrolling the loop is a win on them. 61 * For other arches, we only have a 16bit alignement. 62 */ 63 static unsigned long ifname_compare(const char *_a, const char *_b, const char *_mask) 64 { 65 #ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS 66 unsigned long ret = ifname_compare_aligned(_a, _b, _mask); 67 #else 68 unsigned long ret = 0; 69 const u16 *a = (const u16 *)_a; 70 const u16 *b = (const u16 *)_b; 71 const u16 *mask = (const u16 *)_mask; 72 int i; 73 74 for (i = 0; i < IFNAMSIZ/sizeof(u16); i++) 75 ret |= (a[i] ^ b[i]) & mask[i]; 76 #endif 77 return ret; 78 } 79 80 /* Returns whether packet matches rule or not. */ 81 static inline int arp_packet_match(const struct arphdr *arphdr, 82 struct net_device *dev, 83 const char *indev, 84 const char *outdev, 85 const struct arpt_arp *arpinfo) 86 { 87 const char *arpptr = (char *)(arphdr + 1); 88 const char *src_devaddr, *tgt_devaddr; 89 __be32 src_ipaddr, tgt_ipaddr; 90 long ret; 91 92 if (NF_INVF(arpinfo, ARPT_INV_ARPOP, 93 (arphdr->ar_op & arpinfo->arpop_mask) != arpinfo->arpop)) 94 return 0; 95 96 if (NF_INVF(arpinfo, ARPT_INV_ARPHRD, 97 (arphdr->ar_hrd & arpinfo->arhrd_mask) != arpinfo->arhrd)) 98 return 0; 99 100 if (NF_INVF(arpinfo, ARPT_INV_ARPPRO, 101 (arphdr->ar_pro & arpinfo->arpro_mask) != arpinfo->arpro)) 102 return 0; 103 104 if (NF_INVF(arpinfo, ARPT_INV_ARPHLN, 105 (arphdr->ar_hln & arpinfo->arhln_mask) != arpinfo->arhln)) 106 return 0; 107 108 src_devaddr = arpptr; 109 arpptr += dev->addr_len; 110 memcpy(&src_ipaddr, arpptr, sizeof(u32)); 111 arpptr += sizeof(u32); 112 tgt_devaddr = arpptr; 113 arpptr += dev->addr_len; 114 memcpy(&tgt_ipaddr, arpptr, sizeof(u32)); 115 116 if (NF_INVF(arpinfo, ARPT_INV_SRCDEVADDR, 117 arp_devaddr_compare(&arpinfo->src_devaddr, src_devaddr, 118 dev->addr_len)) || 119 NF_INVF(arpinfo, ARPT_INV_TGTDEVADDR, 120 arp_devaddr_compare(&arpinfo->tgt_devaddr, tgt_devaddr, 121 dev->addr_len))) 122 return 0; 123 124 if (NF_INVF(arpinfo, ARPT_INV_SRCIP, 125 (src_ipaddr & arpinfo->smsk.s_addr) != arpinfo->src.s_addr) || 126 NF_INVF(arpinfo, ARPT_INV_TGTIP, 127 (tgt_ipaddr & arpinfo->tmsk.s_addr) != arpinfo->tgt.s_addr)) 128 return 0; 129 130 /* Look for ifname matches. */ 131 ret = ifname_compare(indev, arpinfo->iniface, arpinfo->iniface_mask); 132 133 if (NF_INVF(arpinfo, ARPT_INV_VIA_IN, ret != 0)) 134 return 0; 135 136 ret = ifname_compare(outdev, arpinfo->outiface, arpinfo->outiface_mask); 137 138 if (NF_INVF(arpinfo, ARPT_INV_VIA_OUT, ret != 0)) 139 return 0; 140 141 return 1; 142 } 143 144 static inline int arp_checkentry(const struct arpt_arp *arp) 145 { 146 if (arp->flags & ~ARPT_F_MASK) 147 return 0; 148 if (arp->invflags & ~ARPT_INV_MASK) 149 return 0; 150 151 return 1; 152 } 153 154 static unsigned int 155 arpt_error(struct sk_buff *skb, const struct xt_action_param *par) 156 { 157 net_err_ratelimited("arp_tables: error: '%s'\n", 158 (const char *)par->targinfo); 159 160 return NF_DROP; 161 } 162 163 static inline const struct xt_entry_target * 164 arpt_get_target_c(const struct arpt_entry *e) 165 { 166 return arpt_get_target((struct arpt_entry *)e); 167 } 168 169 static inline struct arpt_entry * 170 get_entry(const void *base, unsigned int offset) 171 { 172 return (struct arpt_entry *)(base + offset); 173 } 174 175 static inline 176 struct arpt_entry *arpt_next_entry(const struct arpt_entry *entry) 177 { 178 return (void *)entry + entry->next_offset; 179 } 180 181 unsigned int arpt_do_table(struct sk_buff *skb, 182 const struct nf_hook_state *state, 183 struct xt_table *table) 184 { 185 unsigned int hook = state->hook; 186 static const char nulldevname[IFNAMSIZ] __attribute__((aligned(sizeof(long)))); 187 unsigned int verdict = NF_DROP; 188 const struct arphdr *arp; 189 struct arpt_entry *e, **jumpstack; 190 const char *indev, *outdev; 191 const void *table_base; 192 unsigned int cpu, stackidx = 0; 193 const struct xt_table_info *private; 194 struct xt_action_param acpar; 195 unsigned int addend; 196 197 if (!pskb_may_pull(skb, arp_hdr_len(skb->dev))) 198 return NF_DROP; 199 200 indev = state->in ? state->in->name : nulldevname; 201 outdev = state->out ? state->out->name : nulldevname; 202 203 local_bh_disable(); 204 addend = xt_write_recseq_begin(); 205 private = table->private; 206 cpu = smp_processor_id(); 207 /* 208 * Ensure we load private-> members after we've fetched the base 209 * pointer. 210 */ 211 smp_read_barrier_depends(); 212 table_base = private->entries; 213 jumpstack = (struct arpt_entry **)private->jumpstack[cpu]; 214 215 /* No TEE support for arptables, so no need to switch to alternate 216 * stack. All targets that reenter must return absolute verdicts. 217 */ 218 e = get_entry(table_base, private->hook_entry[hook]); 219 220 acpar.state = state; 221 acpar.hotdrop = false; 222 223 arp = arp_hdr(skb); 224 do { 225 const struct xt_entry_target *t; 226 struct xt_counters *counter; 227 228 if (!arp_packet_match(arp, skb->dev, indev, outdev, &e->arp)) { 229 e = arpt_next_entry(e); 230 continue; 231 } 232 233 counter = xt_get_this_cpu_counter(&e->counters); 234 ADD_COUNTER(*counter, arp_hdr_len(skb->dev), 1); 235 236 t = arpt_get_target_c(e); 237 238 /* Standard target? */ 239 if (!t->u.kernel.target->target) { 240 int v; 241 242 v = ((struct xt_standard_target *)t)->verdict; 243 if (v < 0) { 244 /* Pop from stack? */ 245 if (v != XT_RETURN) { 246 verdict = (unsigned int)(-v) - 1; 247 break; 248 } 249 if (stackidx == 0) { 250 e = get_entry(table_base, 251 private->underflow[hook]); 252 } else { 253 e = jumpstack[--stackidx]; 254 e = arpt_next_entry(e); 255 } 256 continue; 257 } 258 if (table_base + v 259 != arpt_next_entry(e)) { 260 jumpstack[stackidx++] = e; 261 } 262 263 e = get_entry(table_base, v); 264 continue; 265 } 266 267 acpar.target = t->u.kernel.target; 268 acpar.targinfo = t->data; 269 verdict = t->u.kernel.target->target(skb, &acpar); 270 271 if (verdict == XT_CONTINUE) { 272 /* Target might have changed stuff. */ 273 arp = arp_hdr(skb); 274 e = arpt_next_entry(e); 275 } else { 276 /* Verdict */ 277 break; 278 } 279 } while (!acpar.hotdrop); 280 xt_write_recseq_end(addend); 281 local_bh_enable(); 282 283 if (acpar.hotdrop) 284 return NF_DROP; 285 else 286 return verdict; 287 } 288 289 /* All zeroes == unconditional rule. */ 290 static inline bool unconditional(const struct arpt_entry *e) 291 { 292 static const struct arpt_arp uncond; 293 294 return e->target_offset == sizeof(struct arpt_entry) && 295 memcmp(&e->arp, &uncond, sizeof(uncond)) == 0; 296 } 297 298 /* Figures out from what hook each rule can be called: returns 0 if 299 * there are loops. Puts hook bitmask in comefrom. 300 */ 301 static int mark_source_chains(const struct xt_table_info *newinfo, 302 unsigned int valid_hooks, void *entry0, 303 unsigned int *offsets) 304 { 305 unsigned int hook; 306 307 /* No recursion; use packet counter to save back ptrs (reset 308 * to 0 as we leave), and comefrom to save source hook bitmask. 309 */ 310 for (hook = 0; hook < NF_ARP_NUMHOOKS; hook++) { 311 unsigned int pos = newinfo->hook_entry[hook]; 312 struct arpt_entry *e = entry0 + pos; 313 314 if (!(valid_hooks & (1 << hook))) 315 continue; 316 317 /* Set initial back pointer. */ 318 e->counters.pcnt = pos; 319 320 for (;;) { 321 const struct xt_standard_target *t 322 = (void *)arpt_get_target_c(e); 323 int visited = e->comefrom & (1 << hook); 324 325 if (e->comefrom & (1 << NF_ARP_NUMHOOKS)) 326 return 0; 327 328 e->comefrom 329 |= ((1 << hook) | (1 << NF_ARP_NUMHOOKS)); 330 331 /* Unconditional return/END. */ 332 if ((unconditional(e) && 333 (strcmp(t->target.u.user.name, 334 XT_STANDARD_TARGET) == 0) && 335 t->verdict < 0) || visited) { 336 unsigned int oldpos, size; 337 338 if ((strcmp(t->target.u.user.name, 339 XT_STANDARD_TARGET) == 0) && 340 t->verdict < -NF_MAX_VERDICT - 1) 341 return 0; 342 343 /* Return: backtrack through the last 344 * big jump. 345 */ 346 do { 347 e->comefrom ^= (1<<NF_ARP_NUMHOOKS); 348 oldpos = pos; 349 pos = e->counters.pcnt; 350 e->counters.pcnt = 0; 351 352 /* We're at the start. */ 353 if (pos == oldpos) 354 goto next; 355 356 e = entry0 + pos; 357 } while (oldpos == pos + e->next_offset); 358 359 /* Move along one */ 360 size = e->next_offset; 361 e = entry0 + pos + size; 362 if (pos + size >= newinfo->size) 363 return 0; 364 e->counters.pcnt = pos; 365 pos += size; 366 } else { 367 int newpos = t->verdict; 368 369 if (strcmp(t->target.u.user.name, 370 XT_STANDARD_TARGET) == 0 && 371 newpos >= 0) { 372 /* This a jump; chase it. */ 373 if (!xt_find_jump_offset(offsets, newpos, 374 newinfo->number)) 375 return 0; 376 e = entry0 + newpos; 377 } else { 378 /* ... this is a fallthru */ 379 newpos = pos + e->next_offset; 380 if (newpos >= newinfo->size) 381 return 0; 382 } 383 e = entry0 + newpos; 384 e->counters.pcnt = pos; 385 pos = newpos; 386 } 387 } 388 next: ; 389 } 390 return 1; 391 } 392 393 static inline int check_target(struct arpt_entry *e, const char *name) 394 { 395 struct xt_entry_target *t = arpt_get_target(e); 396 struct xt_tgchk_param par = { 397 .table = name, 398 .entryinfo = e, 399 .target = t->u.kernel.target, 400 .targinfo = t->data, 401 .hook_mask = e->comefrom, 402 .family = NFPROTO_ARP, 403 }; 404 405 return xt_check_target(&par, t->u.target_size - sizeof(*t), 0, false); 406 } 407 408 static inline int 409 find_check_entry(struct arpt_entry *e, const char *name, unsigned int size, 410 struct xt_percpu_counter_alloc_state *alloc_state) 411 { 412 struct xt_entry_target *t; 413 struct xt_target *target; 414 int ret; 415 416 if (!xt_percpu_counter_alloc(alloc_state, &e->counters)) 417 return -ENOMEM; 418 419 t = arpt_get_target(e); 420 target = xt_request_find_target(NFPROTO_ARP, t->u.user.name, 421 t->u.user.revision); 422 if (IS_ERR(target)) { 423 ret = PTR_ERR(target); 424 goto out; 425 } 426 t->u.kernel.target = target; 427 428 ret = check_target(e, name); 429 if (ret) 430 goto err; 431 return 0; 432 err: 433 module_put(t->u.kernel.target->me); 434 out: 435 xt_percpu_counter_free(&e->counters); 436 437 return ret; 438 } 439 440 static bool check_underflow(const struct arpt_entry *e) 441 { 442 const struct xt_entry_target *t; 443 unsigned int verdict; 444 445 if (!unconditional(e)) 446 return false; 447 t = arpt_get_target_c(e); 448 if (strcmp(t->u.user.name, XT_STANDARD_TARGET) != 0) 449 return false; 450 verdict = ((struct xt_standard_target *)t)->verdict; 451 verdict = -verdict - 1; 452 return verdict == NF_DROP || verdict == NF_ACCEPT; 453 } 454 455 static inline int check_entry_size_and_hooks(struct arpt_entry *e, 456 struct xt_table_info *newinfo, 457 const unsigned char *base, 458 const unsigned char *limit, 459 const unsigned int *hook_entries, 460 const unsigned int *underflows, 461 unsigned int valid_hooks) 462 { 463 unsigned int h; 464 int err; 465 466 if ((unsigned long)e % __alignof__(struct arpt_entry) != 0 || 467 (unsigned char *)e + sizeof(struct arpt_entry) >= limit || 468 (unsigned char *)e + e->next_offset > limit) 469 return -EINVAL; 470 471 if (e->next_offset 472 < sizeof(struct arpt_entry) + sizeof(struct xt_entry_target)) 473 return -EINVAL; 474 475 if (!arp_checkentry(&e->arp)) 476 return -EINVAL; 477 478 err = xt_check_entry_offsets(e, e->elems, e->target_offset, 479 e->next_offset); 480 if (err) 481 return err; 482 483 /* Check hooks & underflows */ 484 for (h = 0; h < NF_ARP_NUMHOOKS; h++) { 485 if (!(valid_hooks & (1 << h))) 486 continue; 487 if ((unsigned char *)e - base == hook_entries[h]) 488 newinfo->hook_entry[h] = hook_entries[h]; 489 if ((unsigned char *)e - base == underflows[h]) { 490 if (!check_underflow(e)) 491 return -EINVAL; 492 493 newinfo->underflow[h] = underflows[h]; 494 } 495 } 496 497 /* Clear counters and comefrom */ 498 e->counters = ((struct xt_counters) { 0, 0 }); 499 e->comefrom = 0; 500 return 0; 501 } 502 503 static inline void cleanup_entry(struct arpt_entry *e) 504 { 505 struct xt_tgdtor_param par; 506 struct xt_entry_target *t; 507 508 t = arpt_get_target(e); 509 par.target = t->u.kernel.target; 510 par.targinfo = t->data; 511 par.family = NFPROTO_ARP; 512 if (par.target->destroy != NULL) 513 par.target->destroy(&par); 514 module_put(par.target->me); 515 xt_percpu_counter_free(&e->counters); 516 } 517 518 /* Checks and translates the user-supplied table segment (held in 519 * newinfo). 520 */ 521 static int translate_table(struct xt_table_info *newinfo, void *entry0, 522 const struct arpt_replace *repl) 523 { 524 struct xt_percpu_counter_alloc_state alloc_state = { 0 }; 525 struct arpt_entry *iter; 526 unsigned int *offsets; 527 unsigned int i; 528 int ret = 0; 529 530 newinfo->size = repl->size; 531 newinfo->number = repl->num_entries; 532 533 /* Init all hooks to impossible value. */ 534 for (i = 0; i < NF_ARP_NUMHOOKS; i++) { 535 newinfo->hook_entry[i] = 0xFFFFFFFF; 536 newinfo->underflow[i] = 0xFFFFFFFF; 537 } 538 539 offsets = xt_alloc_entry_offsets(newinfo->number); 540 if (!offsets) 541 return -ENOMEM; 542 i = 0; 543 544 /* Walk through entries, checking offsets. */ 545 xt_entry_foreach(iter, entry0, newinfo->size) { 546 ret = check_entry_size_and_hooks(iter, newinfo, entry0, 547 entry0 + repl->size, 548 repl->hook_entry, 549 repl->underflow, 550 repl->valid_hooks); 551 if (ret != 0) 552 goto out_free; 553 if (i < repl->num_entries) 554 offsets[i] = (void *)iter - entry0; 555 ++i; 556 if (strcmp(arpt_get_target(iter)->u.user.name, 557 XT_ERROR_TARGET) == 0) 558 ++newinfo->stacksize; 559 } 560 561 ret = -EINVAL; 562 if (i != repl->num_entries) 563 goto out_free; 564 565 /* Check hooks all assigned */ 566 for (i = 0; i < NF_ARP_NUMHOOKS; i++) { 567 /* Only hooks which are valid */ 568 if (!(repl->valid_hooks & (1 << i))) 569 continue; 570 if (newinfo->hook_entry[i] == 0xFFFFFFFF) 571 goto out_free; 572 if (newinfo->underflow[i] == 0xFFFFFFFF) 573 goto out_free; 574 } 575 576 if (!mark_source_chains(newinfo, repl->valid_hooks, entry0, offsets)) { 577 ret = -ELOOP; 578 goto out_free; 579 } 580 kvfree(offsets); 581 582 /* Finally, each sanity check must pass */ 583 i = 0; 584 xt_entry_foreach(iter, entry0, newinfo->size) { 585 ret = find_check_entry(iter, repl->name, repl->size, 586 &alloc_state); 587 if (ret != 0) 588 break; 589 ++i; 590 } 591 592 if (ret != 0) { 593 xt_entry_foreach(iter, entry0, newinfo->size) { 594 if (i-- == 0) 595 break; 596 cleanup_entry(iter); 597 } 598 return ret; 599 } 600 601 return ret; 602 out_free: 603 kvfree(offsets); 604 return ret; 605 } 606 607 static void get_counters(const struct xt_table_info *t, 608 struct xt_counters counters[]) 609 { 610 struct arpt_entry *iter; 611 unsigned int cpu; 612 unsigned int i; 613 614 for_each_possible_cpu(cpu) { 615 seqcount_t *s = &per_cpu(xt_recseq, cpu); 616 617 i = 0; 618 xt_entry_foreach(iter, t->entries, t->size) { 619 struct xt_counters *tmp; 620 u64 bcnt, pcnt; 621 unsigned int start; 622 623 tmp = xt_get_per_cpu_counter(&iter->counters, cpu); 624 do { 625 start = read_seqcount_begin(s); 626 bcnt = tmp->bcnt; 627 pcnt = tmp->pcnt; 628 } while (read_seqcount_retry(s, start)); 629 630 ADD_COUNTER(counters[i], bcnt, pcnt); 631 ++i; 632 cond_resched(); 633 } 634 } 635 } 636 637 static struct xt_counters *alloc_counters(const struct xt_table *table) 638 { 639 unsigned int countersize; 640 struct xt_counters *counters; 641 const struct xt_table_info *private = table->private; 642 643 /* We need atomic snapshot of counters: rest doesn't change 644 * (other than comefrom, which userspace doesn't care 645 * about). 646 */ 647 countersize = sizeof(struct xt_counters) * private->number; 648 counters = vzalloc(countersize); 649 650 if (counters == NULL) 651 return ERR_PTR(-ENOMEM); 652 653 get_counters(private, counters); 654 655 return counters; 656 } 657 658 static int copy_entries_to_user(unsigned int total_size, 659 const struct xt_table *table, 660 void __user *userptr) 661 { 662 unsigned int off, num; 663 const struct arpt_entry *e; 664 struct xt_counters *counters; 665 struct xt_table_info *private = table->private; 666 int ret = 0; 667 void *loc_cpu_entry; 668 669 counters = alloc_counters(table); 670 if (IS_ERR(counters)) 671 return PTR_ERR(counters); 672 673 loc_cpu_entry = private->entries; 674 675 /* FIXME: use iterator macros --RR */ 676 /* ... then go back and fix counters and names */ 677 for (off = 0, num = 0; off < total_size; off += e->next_offset, num++){ 678 const struct xt_entry_target *t; 679 680 e = loc_cpu_entry + off; 681 if (copy_to_user(userptr + off, e, sizeof(*e))) { 682 ret = -EFAULT; 683 goto free_counters; 684 } 685 if (copy_to_user(userptr + off 686 + offsetof(struct arpt_entry, counters), 687 &counters[num], 688 sizeof(counters[num])) != 0) { 689 ret = -EFAULT; 690 goto free_counters; 691 } 692 693 t = arpt_get_target_c(e); 694 if (xt_target_to_user(t, userptr + off + e->target_offset)) { 695 ret = -EFAULT; 696 goto free_counters; 697 } 698 } 699 700 free_counters: 701 vfree(counters); 702 return ret; 703 } 704 705 #ifdef CONFIG_COMPAT 706 static void compat_standard_from_user(void *dst, const void *src) 707 { 708 int v = *(compat_int_t *)src; 709 710 if (v > 0) 711 v += xt_compat_calc_jump(NFPROTO_ARP, v); 712 memcpy(dst, &v, sizeof(v)); 713 } 714 715 static int compat_standard_to_user(void __user *dst, const void *src) 716 { 717 compat_int_t cv = *(int *)src; 718 719 if (cv > 0) 720 cv -= xt_compat_calc_jump(NFPROTO_ARP, cv); 721 return copy_to_user(dst, &cv, sizeof(cv)) ? -EFAULT : 0; 722 } 723 724 static int compat_calc_entry(const struct arpt_entry *e, 725 const struct xt_table_info *info, 726 const void *base, struct xt_table_info *newinfo) 727 { 728 const struct xt_entry_target *t; 729 unsigned int entry_offset; 730 int off, i, ret; 731 732 off = sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry); 733 entry_offset = (void *)e - base; 734 735 t = arpt_get_target_c(e); 736 off += xt_compat_target_offset(t->u.kernel.target); 737 newinfo->size -= off; 738 ret = xt_compat_add_offset(NFPROTO_ARP, entry_offset, off); 739 if (ret) 740 return ret; 741 742 for (i = 0; i < NF_ARP_NUMHOOKS; i++) { 743 if (info->hook_entry[i] && 744 (e < (struct arpt_entry *)(base + info->hook_entry[i]))) 745 newinfo->hook_entry[i] -= off; 746 if (info->underflow[i] && 747 (e < (struct arpt_entry *)(base + info->underflow[i]))) 748 newinfo->underflow[i] -= off; 749 } 750 return 0; 751 } 752 753 static int compat_table_info(const struct xt_table_info *info, 754 struct xt_table_info *newinfo) 755 { 756 struct arpt_entry *iter; 757 const void *loc_cpu_entry; 758 int ret; 759 760 if (!newinfo || !info) 761 return -EINVAL; 762 763 /* we dont care about newinfo->entries */ 764 memcpy(newinfo, info, offsetof(struct xt_table_info, entries)); 765 newinfo->initial_entries = 0; 766 loc_cpu_entry = info->entries; 767 xt_compat_init_offsets(NFPROTO_ARP, info->number); 768 xt_entry_foreach(iter, loc_cpu_entry, info->size) { 769 ret = compat_calc_entry(iter, info, loc_cpu_entry, newinfo); 770 if (ret != 0) 771 return ret; 772 } 773 return 0; 774 } 775 #endif 776 777 static int get_info(struct net *net, void __user *user, 778 const int *len, int compat) 779 { 780 char name[XT_TABLE_MAXNAMELEN]; 781 struct xt_table *t; 782 int ret; 783 784 if (*len != sizeof(struct arpt_getinfo)) 785 return -EINVAL; 786 787 if (copy_from_user(name, user, sizeof(name)) != 0) 788 return -EFAULT; 789 790 name[XT_TABLE_MAXNAMELEN-1] = '\0'; 791 #ifdef CONFIG_COMPAT 792 if (compat) 793 xt_compat_lock(NFPROTO_ARP); 794 #endif 795 t = try_then_request_module(xt_find_table_lock(net, NFPROTO_ARP, name), 796 "arptable_%s", name); 797 if (t) { 798 struct arpt_getinfo info; 799 const struct xt_table_info *private = t->private; 800 #ifdef CONFIG_COMPAT 801 struct xt_table_info tmp; 802 803 if (compat) { 804 ret = compat_table_info(private, &tmp); 805 xt_compat_flush_offsets(NFPROTO_ARP); 806 private = &tmp; 807 } 808 #endif 809 memset(&info, 0, sizeof(info)); 810 info.valid_hooks = t->valid_hooks; 811 memcpy(info.hook_entry, private->hook_entry, 812 sizeof(info.hook_entry)); 813 memcpy(info.underflow, private->underflow, 814 sizeof(info.underflow)); 815 info.num_entries = private->number; 816 info.size = private->size; 817 strcpy(info.name, name); 818 819 if (copy_to_user(user, &info, *len) != 0) 820 ret = -EFAULT; 821 else 822 ret = 0; 823 xt_table_unlock(t); 824 module_put(t->me); 825 } else 826 ret = -ENOENT; 827 #ifdef CONFIG_COMPAT 828 if (compat) 829 xt_compat_unlock(NFPROTO_ARP); 830 #endif 831 return ret; 832 } 833 834 static int get_entries(struct net *net, struct arpt_get_entries __user *uptr, 835 const int *len) 836 { 837 int ret; 838 struct arpt_get_entries get; 839 struct xt_table *t; 840 841 if (*len < sizeof(get)) 842 return -EINVAL; 843 if (copy_from_user(&get, uptr, sizeof(get)) != 0) 844 return -EFAULT; 845 if (*len != sizeof(struct arpt_get_entries) + get.size) 846 return -EINVAL; 847 848 get.name[sizeof(get.name) - 1] = '\0'; 849 850 t = xt_find_table_lock(net, NFPROTO_ARP, get.name); 851 if (t) { 852 const struct xt_table_info *private = t->private; 853 854 if (get.size == private->size) 855 ret = copy_entries_to_user(private->size, 856 t, uptr->entrytable); 857 else 858 ret = -EAGAIN; 859 860 module_put(t->me); 861 xt_table_unlock(t); 862 } else 863 ret = -ENOENT; 864 865 return ret; 866 } 867 868 static int __do_replace(struct net *net, const char *name, 869 unsigned int valid_hooks, 870 struct xt_table_info *newinfo, 871 unsigned int num_counters, 872 void __user *counters_ptr) 873 { 874 int ret; 875 struct xt_table *t; 876 struct xt_table_info *oldinfo; 877 struct xt_counters *counters; 878 void *loc_cpu_old_entry; 879 struct arpt_entry *iter; 880 881 ret = 0; 882 counters = vzalloc(num_counters * sizeof(struct xt_counters)); 883 if (!counters) { 884 ret = -ENOMEM; 885 goto out; 886 } 887 888 t = try_then_request_module(xt_find_table_lock(net, NFPROTO_ARP, name), 889 "arptable_%s", name); 890 if (!t) { 891 ret = -ENOENT; 892 goto free_newinfo_counters_untrans; 893 } 894 895 /* You lied! */ 896 if (valid_hooks != t->valid_hooks) { 897 ret = -EINVAL; 898 goto put_module; 899 } 900 901 oldinfo = xt_replace_table(t, num_counters, newinfo, &ret); 902 if (!oldinfo) 903 goto put_module; 904 905 /* Update module usage count based on number of rules */ 906 if ((oldinfo->number > oldinfo->initial_entries) || 907 (newinfo->number <= oldinfo->initial_entries)) 908 module_put(t->me); 909 if ((oldinfo->number > oldinfo->initial_entries) && 910 (newinfo->number <= oldinfo->initial_entries)) 911 module_put(t->me); 912 913 /* Get the old counters, and synchronize with replace */ 914 get_counters(oldinfo, counters); 915 916 /* Decrease module usage counts and free resource */ 917 loc_cpu_old_entry = oldinfo->entries; 918 xt_entry_foreach(iter, loc_cpu_old_entry, oldinfo->size) 919 cleanup_entry(iter); 920 921 xt_free_table_info(oldinfo); 922 if (copy_to_user(counters_ptr, counters, 923 sizeof(struct xt_counters) * num_counters) != 0) { 924 /* Silent error, can't fail, new table is already in place */ 925 net_warn_ratelimited("arptables: counters copy to user failed while replacing table\n"); 926 } 927 vfree(counters); 928 xt_table_unlock(t); 929 return ret; 930 931 put_module: 932 module_put(t->me); 933 xt_table_unlock(t); 934 free_newinfo_counters_untrans: 935 vfree(counters); 936 out: 937 return ret; 938 } 939 940 static int do_replace(struct net *net, const void __user *user, 941 unsigned int len) 942 { 943 int ret; 944 struct arpt_replace tmp; 945 struct xt_table_info *newinfo; 946 void *loc_cpu_entry; 947 struct arpt_entry *iter; 948 949 if (copy_from_user(&tmp, user, sizeof(tmp)) != 0) 950 return -EFAULT; 951 952 /* overflow check */ 953 if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters)) 954 return -ENOMEM; 955 if (tmp.num_counters == 0) 956 return -EINVAL; 957 958 tmp.name[sizeof(tmp.name)-1] = 0; 959 960 newinfo = xt_alloc_table_info(tmp.size); 961 if (!newinfo) 962 return -ENOMEM; 963 964 loc_cpu_entry = newinfo->entries; 965 if (copy_from_user(loc_cpu_entry, user + sizeof(tmp), 966 tmp.size) != 0) { 967 ret = -EFAULT; 968 goto free_newinfo; 969 } 970 971 ret = translate_table(newinfo, loc_cpu_entry, &tmp); 972 if (ret != 0) 973 goto free_newinfo; 974 975 ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo, 976 tmp.num_counters, tmp.counters); 977 if (ret) 978 goto free_newinfo_untrans; 979 return 0; 980 981 free_newinfo_untrans: 982 xt_entry_foreach(iter, loc_cpu_entry, newinfo->size) 983 cleanup_entry(iter); 984 free_newinfo: 985 xt_free_table_info(newinfo); 986 return ret; 987 } 988 989 static int do_add_counters(struct net *net, const void __user *user, 990 unsigned int len, int compat) 991 { 992 unsigned int i; 993 struct xt_counters_info tmp; 994 struct xt_counters *paddc; 995 struct xt_table *t; 996 const struct xt_table_info *private; 997 int ret = 0; 998 struct arpt_entry *iter; 999 unsigned int addend; 1000 1001 paddc = xt_copy_counters_from_user(user, len, &tmp, compat); 1002 if (IS_ERR(paddc)) 1003 return PTR_ERR(paddc); 1004 1005 t = xt_find_table_lock(net, NFPROTO_ARP, tmp.name); 1006 if (!t) { 1007 ret = -ENOENT; 1008 goto free; 1009 } 1010 1011 local_bh_disable(); 1012 private = t->private; 1013 if (private->number != tmp.num_counters) { 1014 ret = -EINVAL; 1015 goto unlock_up_free; 1016 } 1017 1018 i = 0; 1019 1020 addend = xt_write_recseq_begin(); 1021 xt_entry_foreach(iter, private->entries, private->size) { 1022 struct xt_counters *tmp; 1023 1024 tmp = xt_get_this_cpu_counter(&iter->counters); 1025 ADD_COUNTER(*tmp, paddc[i].bcnt, paddc[i].pcnt); 1026 ++i; 1027 } 1028 xt_write_recseq_end(addend); 1029 unlock_up_free: 1030 local_bh_enable(); 1031 xt_table_unlock(t); 1032 module_put(t->me); 1033 free: 1034 vfree(paddc); 1035 1036 return ret; 1037 } 1038 1039 #ifdef CONFIG_COMPAT 1040 struct compat_arpt_replace { 1041 char name[XT_TABLE_MAXNAMELEN]; 1042 u32 valid_hooks; 1043 u32 num_entries; 1044 u32 size; 1045 u32 hook_entry[NF_ARP_NUMHOOKS]; 1046 u32 underflow[NF_ARP_NUMHOOKS]; 1047 u32 num_counters; 1048 compat_uptr_t counters; 1049 struct compat_arpt_entry entries[0]; 1050 }; 1051 1052 static inline void compat_release_entry(struct compat_arpt_entry *e) 1053 { 1054 struct xt_entry_target *t; 1055 1056 t = compat_arpt_get_target(e); 1057 module_put(t->u.kernel.target->me); 1058 } 1059 1060 static int 1061 check_compat_entry_size_and_hooks(struct compat_arpt_entry *e, 1062 struct xt_table_info *newinfo, 1063 unsigned int *size, 1064 const unsigned char *base, 1065 const unsigned char *limit) 1066 { 1067 struct xt_entry_target *t; 1068 struct xt_target *target; 1069 unsigned int entry_offset; 1070 int ret, off; 1071 1072 if ((unsigned long)e % __alignof__(struct compat_arpt_entry) != 0 || 1073 (unsigned char *)e + sizeof(struct compat_arpt_entry) >= limit || 1074 (unsigned char *)e + e->next_offset > limit) 1075 return -EINVAL; 1076 1077 if (e->next_offset < sizeof(struct compat_arpt_entry) + 1078 sizeof(struct compat_xt_entry_target)) 1079 return -EINVAL; 1080 1081 if (!arp_checkentry(&e->arp)) 1082 return -EINVAL; 1083 1084 ret = xt_compat_check_entry_offsets(e, e->elems, e->target_offset, 1085 e->next_offset); 1086 if (ret) 1087 return ret; 1088 1089 off = sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry); 1090 entry_offset = (void *)e - (void *)base; 1091 1092 t = compat_arpt_get_target(e); 1093 target = xt_request_find_target(NFPROTO_ARP, t->u.user.name, 1094 t->u.user.revision); 1095 if (IS_ERR(target)) { 1096 ret = PTR_ERR(target); 1097 goto out; 1098 } 1099 t->u.kernel.target = target; 1100 1101 off += xt_compat_target_offset(target); 1102 *size += off; 1103 ret = xt_compat_add_offset(NFPROTO_ARP, entry_offset, off); 1104 if (ret) 1105 goto release_target; 1106 1107 return 0; 1108 1109 release_target: 1110 module_put(t->u.kernel.target->me); 1111 out: 1112 return ret; 1113 } 1114 1115 static void 1116 compat_copy_entry_from_user(struct compat_arpt_entry *e, void **dstptr, 1117 unsigned int *size, 1118 struct xt_table_info *newinfo, unsigned char *base) 1119 { 1120 struct xt_entry_target *t; 1121 struct arpt_entry *de; 1122 unsigned int origsize; 1123 int h; 1124 1125 origsize = *size; 1126 de = *dstptr; 1127 memcpy(de, e, sizeof(struct arpt_entry)); 1128 memcpy(&de->counters, &e->counters, sizeof(e->counters)); 1129 1130 *dstptr += sizeof(struct arpt_entry); 1131 *size += sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry); 1132 1133 de->target_offset = e->target_offset - (origsize - *size); 1134 t = compat_arpt_get_target(e); 1135 xt_compat_target_from_user(t, dstptr, size); 1136 1137 de->next_offset = e->next_offset - (origsize - *size); 1138 for (h = 0; h < NF_ARP_NUMHOOKS; h++) { 1139 if ((unsigned char *)de - base < newinfo->hook_entry[h]) 1140 newinfo->hook_entry[h] -= origsize - *size; 1141 if ((unsigned char *)de - base < newinfo->underflow[h]) 1142 newinfo->underflow[h] -= origsize - *size; 1143 } 1144 } 1145 1146 static int translate_compat_table(struct xt_table_info **pinfo, 1147 void **pentry0, 1148 const struct compat_arpt_replace *compatr) 1149 { 1150 unsigned int i, j; 1151 struct xt_table_info *newinfo, *info; 1152 void *pos, *entry0, *entry1; 1153 struct compat_arpt_entry *iter0; 1154 struct arpt_replace repl; 1155 unsigned int size; 1156 int ret = 0; 1157 1158 info = *pinfo; 1159 entry0 = *pentry0; 1160 size = compatr->size; 1161 info->number = compatr->num_entries; 1162 1163 j = 0; 1164 xt_compat_lock(NFPROTO_ARP); 1165 xt_compat_init_offsets(NFPROTO_ARP, compatr->num_entries); 1166 /* Walk through entries, checking offsets. */ 1167 xt_entry_foreach(iter0, entry0, compatr->size) { 1168 ret = check_compat_entry_size_and_hooks(iter0, info, &size, 1169 entry0, 1170 entry0 + compatr->size); 1171 if (ret != 0) 1172 goto out_unlock; 1173 ++j; 1174 } 1175 1176 ret = -EINVAL; 1177 if (j != compatr->num_entries) 1178 goto out_unlock; 1179 1180 ret = -ENOMEM; 1181 newinfo = xt_alloc_table_info(size); 1182 if (!newinfo) 1183 goto out_unlock; 1184 1185 newinfo->number = compatr->num_entries; 1186 for (i = 0; i < NF_ARP_NUMHOOKS; i++) { 1187 newinfo->hook_entry[i] = compatr->hook_entry[i]; 1188 newinfo->underflow[i] = compatr->underflow[i]; 1189 } 1190 entry1 = newinfo->entries; 1191 pos = entry1; 1192 size = compatr->size; 1193 xt_entry_foreach(iter0, entry0, compatr->size) 1194 compat_copy_entry_from_user(iter0, &pos, &size, 1195 newinfo, entry1); 1196 1197 /* all module references in entry0 are now gone */ 1198 1199 xt_compat_flush_offsets(NFPROTO_ARP); 1200 xt_compat_unlock(NFPROTO_ARP); 1201 1202 memcpy(&repl, compatr, sizeof(*compatr)); 1203 1204 for (i = 0; i < NF_ARP_NUMHOOKS; i++) { 1205 repl.hook_entry[i] = newinfo->hook_entry[i]; 1206 repl.underflow[i] = newinfo->underflow[i]; 1207 } 1208 1209 repl.num_counters = 0; 1210 repl.counters = NULL; 1211 repl.size = newinfo->size; 1212 ret = translate_table(newinfo, entry1, &repl); 1213 if (ret) 1214 goto free_newinfo; 1215 1216 *pinfo = newinfo; 1217 *pentry0 = entry1; 1218 xt_free_table_info(info); 1219 return 0; 1220 1221 free_newinfo: 1222 xt_free_table_info(newinfo); 1223 return ret; 1224 out_unlock: 1225 xt_compat_flush_offsets(NFPROTO_ARP); 1226 xt_compat_unlock(NFPROTO_ARP); 1227 xt_entry_foreach(iter0, entry0, compatr->size) { 1228 if (j-- == 0) 1229 break; 1230 compat_release_entry(iter0); 1231 } 1232 return ret; 1233 } 1234 1235 static int compat_do_replace(struct net *net, void __user *user, 1236 unsigned int len) 1237 { 1238 int ret; 1239 struct compat_arpt_replace tmp; 1240 struct xt_table_info *newinfo; 1241 void *loc_cpu_entry; 1242 struct arpt_entry *iter; 1243 1244 if (copy_from_user(&tmp, user, sizeof(tmp)) != 0) 1245 return -EFAULT; 1246 1247 /* overflow check */ 1248 if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters)) 1249 return -ENOMEM; 1250 if (tmp.num_counters == 0) 1251 return -EINVAL; 1252 1253 tmp.name[sizeof(tmp.name)-1] = 0; 1254 1255 newinfo = xt_alloc_table_info(tmp.size); 1256 if (!newinfo) 1257 return -ENOMEM; 1258 1259 loc_cpu_entry = newinfo->entries; 1260 if (copy_from_user(loc_cpu_entry, user + sizeof(tmp), tmp.size) != 0) { 1261 ret = -EFAULT; 1262 goto free_newinfo; 1263 } 1264 1265 ret = translate_compat_table(&newinfo, &loc_cpu_entry, &tmp); 1266 if (ret != 0) 1267 goto free_newinfo; 1268 1269 ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo, 1270 tmp.num_counters, compat_ptr(tmp.counters)); 1271 if (ret) 1272 goto free_newinfo_untrans; 1273 return 0; 1274 1275 free_newinfo_untrans: 1276 xt_entry_foreach(iter, loc_cpu_entry, newinfo->size) 1277 cleanup_entry(iter); 1278 free_newinfo: 1279 xt_free_table_info(newinfo); 1280 return ret; 1281 } 1282 1283 static int compat_do_arpt_set_ctl(struct sock *sk, int cmd, void __user *user, 1284 unsigned int len) 1285 { 1286 int ret; 1287 1288 if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN)) 1289 return -EPERM; 1290 1291 switch (cmd) { 1292 case ARPT_SO_SET_REPLACE: 1293 ret = compat_do_replace(sock_net(sk), user, len); 1294 break; 1295 1296 case ARPT_SO_SET_ADD_COUNTERS: 1297 ret = do_add_counters(sock_net(sk), user, len, 1); 1298 break; 1299 1300 default: 1301 ret = -EINVAL; 1302 } 1303 1304 return ret; 1305 } 1306 1307 static int compat_copy_entry_to_user(struct arpt_entry *e, void __user **dstptr, 1308 compat_uint_t *size, 1309 struct xt_counters *counters, 1310 unsigned int i) 1311 { 1312 struct xt_entry_target *t; 1313 struct compat_arpt_entry __user *ce; 1314 u_int16_t target_offset, next_offset; 1315 compat_uint_t origsize; 1316 int ret; 1317 1318 origsize = *size; 1319 ce = *dstptr; 1320 if (copy_to_user(ce, e, sizeof(struct arpt_entry)) != 0 || 1321 copy_to_user(&ce->counters, &counters[i], 1322 sizeof(counters[i])) != 0) 1323 return -EFAULT; 1324 1325 *dstptr += sizeof(struct compat_arpt_entry); 1326 *size -= sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry); 1327 1328 target_offset = e->target_offset - (origsize - *size); 1329 1330 t = arpt_get_target(e); 1331 ret = xt_compat_target_to_user(t, dstptr, size); 1332 if (ret) 1333 return ret; 1334 next_offset = e->next_offset - (origsize - *size); 1335 if (put_user(target_offset, &ce->target_offset) != 0 || 1336 put_user(next_offset, &ce->next_offset) != 0) 1337 return -EFAULT; 1338 return 0; 1339 } 1340 1341 static int compat_copy_entries_to_user(unsigned int total_size, 1342 struct xt_table *table, 1343 void __user *userptr) 1344 { 1345 struct xt_counters *counters; 1346 const struct xt_table_info *private = table->private; 1347 void __user *pos; 1348 unsigned int size; 1349 int ret = 0; 1350 unsigned int i = 0; 1351 struct arpt_entry *iter; 1352 1353 counters = alloc_counters(table); 1354 if (IS_ERR(counters)) 1355 return PTR_ERR(counters); 1356 1357 pos = userptr; 1358 size = total_size; 1359 xt_entry_foreach(iter, private->entries, total_size) { 1360 ret = compat_copy_entry_to_user(iter, &pos, 1361 &size, counters, i++); 1362 if (ret != 0) 1363 break; 1364 } 1365 vfree(counters); 1366 return ret; 1367 } 1368 1369 struct compat_arpt_get_entries { 1370 char name[XT_TABLE_MAXNAMELEN]; 1371 compat_uint_t size; 1372 struct compat_arpt_entry entrytable[0]; 1373 }; 1374 1375 static int compat_get_entries(struct net *net, 1376 struct compat_arpt_get_entries __user *uptr, 1377 int *len) 1378 { 1379 int ret; 1380 struct compat_arpt_get_entries get; 1381 struct xt_table *t; 1382 1383 if (*len < sizeof(get)) 1384 return -EINVAL; 1385 if (copy_from_user(&get, uptr, sizeof(get)) != 0) 1386 return -EFAULT; 1387 if (*len != sizeof(struct compat_arpt_get_entries) + get.size) 1388 return -EINVAL; 1389 1390 get.name[sizeof(get.name) - 1] = '\0'; 1391 1392 xt_compat_lock(NFPROTO_ARP); 1393 t = xt_find_table_lock(net, NFPROTO_ARP, get.name); 1394 if (t) { 1395 const struct xt_table_info *private = t->private; 1396 struct xt_table_info info; 1397 1398 ret = compat_table_info(private, &info); 1399 if (!ret && get.size == info.size) { 1400 ret = compat_copy_entries_to_user(private->size, 1401 t, uptr->entrytable); 1402 } else if (!ret) 1403 ret = -EAGAIN; 1404 1405 xt_compat_flush_offsets(NFPROTO_ARP); 1406 module_put(t->me); 1407 xt_table_unlock(t); 1408 } else 1409 ret = -ENOENT; 1410 1411 xt_compat_unlock(NFPROTO_ARP); 1412 return ret; 1413 } 1414 1415 static int do_arpt_get_ctl(struct sock *, int, void __user *, int *); 1416 1417 static int compat_do_arpt_get_ctl(struct sock *sk, int cmd, void __user *user, 1418 int *len) 1419 { 1420 int ret; 1421 1422 if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN)) 1423 return -EPERM; 1424 1425 switch (cmd) { 1426 case ARPT_SO_GET_INFO: 1427 ret = get_info(sock_net(sk), user, len, 1); 1428 break; 1429 case ARPT_SO_GET_ENTRIES: 1430 ret = compat_get_entries(sock_net(sk), user, len); 1431 break; 1432 default: 1433 ret = do_arpt_get_ctl(sk, cmd, user, len); 1434 } 1435 return ret; 1436 } 1437 #endif 1438 1439 static int do_arpt_set_ctl(struct sock *sk, int cmd, void __user *user, unsigned int len) 1440 { 1441 int ret; 1442 1443 if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN)) 1444 return -EPERM; 1445 1446 switch (cmd) { 1447 case ARPT_SO_SET_REPLACE: 1448 ret = do_replace(sock_net(sk), user, len); 1449 break; 1450 1451 case ARPT_SO_SET_ADD_COUNTERS: 1452 ret = do_add_counters(sock_net(sk), user, len, 0); 1453 break; 1454 1455 default: 1456 ret = -EINVAL; 1457 } 1458 1459 return ret; 1460 } 1461 1462 static int do_arpt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len) 1463 { 1464 int ret; 1465 1466 if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN)) 1467 return -EPERM; 1468 1469 switch (cmd) { 1470 case ARPT_SO_GET_INFO: 1471 ret = get_info(sock_net(sk), user, len, 0); 1472 break; 1473 1474 case ARPT_SO_GET_ENTRIES: 1475 ret = get_entries(sock_net(sk), user, len); 1476 break; 1477 1478 case ARPT_SO_GET_REVISION_TARGET: { 1479 struct xt_get_revision rev; 1480 1481 if (*len != sizeof(rev)) { 1482 ret = -EINVAL; 1483 break; 1484 } 1485 if (copy_from_user(&rev, user, sizeof(rev)) != 0) { 1486 ret = -EFAULT; 1487 break; 1488 } 1489 rev.name[sizeof(rev.name)-1] = 0; 1490 1491 try_then_request_module(xt_find_revision(NFPROTO_ARP, rev.name, 1492 rev.revision, 1, &ret), 1493 "arpt_%s", rev.name); 1494 break; 1495 } 1496 1497 default: 1498 ret = -EINVAL; 1499 } 1500 1501 return ret; 1502 } 1503 1504 static void __arpt_unregister_table(struct xt_table *table) 1505 { 1506 struct xt_table_info *private; 1507 void *loc_cpu_entry; 1508 struct module *table_owner = table->me; 1509 struct arpt_entry *iter; 1510 1511 private = xt_unregister_table(table); 1512 1513 /* Decrease module usage counts and free resources */ 1514 loc_cpu_entry = private->entries; 1515 xt_entry_foreach(iter, loc_cpu_entry, private->size) 1516 cleanup_entry(iter); 1517 if (private->number > private->initial_entries) 1518 module_put(table_owner); 1519 xt_free_table_info(private); 1520 } 1521 1522 int arpt_register_table(struct net *net, 1523 const struct xt_table *table, 1524 const struct arpt_replace *repl, 1525 const struct nf_hook_ops *ops, 1526 struct xt_table **res) 1527 { 1528 int ret; 1529 struct xt_table_info *newinfo; 1530 struct xt_table_info bootstrap = {0}; 1531 void *loc_cpu_entry; 1532 struct xt_table *new_table; 1533 1534 newinfo = xt_alloc_table_info(repl->size); 1535 if (!newinfo) 1536 return -ENOMEM; 1537 1538 loc_cpu_entry = newinfo->entries; 1539 memcpy(loc_cpu_entry, repl->entries, repl->size); 1540 1541 ret = translate_table(newinfo, loc_cpu_entry, repl); 1542 if (ret != 0) 1543 goto out_free; 1544 1545 new_table = xt_register_table(net, table, &bootstrap, newinfo); 1546 if (IS_ERR(new_table)) { 1547 ret = PTR_ERR(new_table); 1548 goto out_free; 1549 } 1550 1551 /* set res now, will see skbs right after nf_register_net_hooks */ 1552 WRITE_ONCE(*res, new_table); 1553 1554 ret = nf_register_net_hooks(net, ops, hweight32(table->valid_hooks)); 1555 if (ret != 0) { 1556 __arpt_unregister_table(new_table); 1557 *res = NULL; 1558 } 1559 1560 return ret; 1561 1562 out_free: 1563 xt_free_table_info(newinfo); 1564 return ret; 1565 } 1566 1567 void arpt_unregister_table(struct net *net, struct xt_table *table, 1568 const struct nf_hook_ops *ops) 1569 { 1570 nf_unregister_net_hooks(net, ops, hweight32(table->valid_hooks)); 1571 __arpt_unregister_table(table); 1572 } 1573 1574 /* The built-in targets: standard (NULL) and error. */ 1575 static struct xt_target arpt_builtin_tg[] __read_mostly = { 1576 { 1577 .name = XT_STANDARD_TARGET, 1578 .targetsize = sizeof(int), 1579 .family = NFPROTO_ARP, 1580 #ifdef CONFIG_COMPAT 1581 .compatsize = sizeof(compat_int_t), 1582 .compat_from_user = compat_standard_from_user, 1583 .compat_to_user = compat_standard_to_user, 1584 #endif 1585 }, 1586 { 1587 .name = XT_ERROR_TARGET, 1588 .target = arpt_error, 1589 .targetsize = XT_FUNCTION_MAXNAMELEN, 1590 .family = NFPROTO_ARP, 1591 }, 1592 }; 1593 1594 static struct nf_sockopt_ops arpt_sockopts = { 1595 .pf = PF_INET, 1596 .set_optmin = ARPT_BASE_CTL, 1597 .set_optmax = ARPT_SO_SET_MAX+1, 1598 .set = do_arpt_set_ctl, 1599 #ifdef CONFIG_COMPAT 1600 .compat_set = compat_do_arpt_set_ctl, 1601 #endif 1602 .get_optmin = ARPT_BASE_CTL, 1603 .get_optmax = ARPT_SO_GET_MAX+1, 1604 .get = do_arpt_get_ctl, 1605 #ifdef CONFIG_COMPAT 1606 .compat_get = compat_do_arpt_get_ctl, 1607 #endif 1608 .owner = THIS_MODULE, 1609 }; 1610 1611 static int __net_init arp_tables_net_init(struct net *net) 1612 { 1613 return xt_proto_init(net, NFPROTO_ARP); 1614 } 1615 1616 static void __net_exit arp_tables_net_exit(struct net *net) 1617 { 1618 xt_proto_fini(net, NFPROTO_ARP); 1619 } 1620 1621 static struct pernet_operations arp_tables_net_ops = { 1622 .init = arp_tables_net_init, 1623 .exit = arp_tables_net_exit, 1624 }; 1625 1626 static int __init arp_tables_init(void) 1627 { 1628 int ret; 1629 1630 ret = register_pernet_subsys(&arp_tables_net_ops); 1631 if (ret < 0) 1632 goto err1; 1633 1634 /* No one else will be downing sem now, so we won't sleep */ 1635 ret = xt_register_targets(arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg)); 1636 if (ret < 0) 1637 goto err2; 1638 1639 /* Register setsockopt */ 1640 ret = nf_register_sockopt(&arpt_sockopts); 1641 if (ret < 0) 1642 goto err4; 1643 1644 pr_info("arp_tables: (C) 2002 David S. Miller\n"); 1645 return 0; 1646 1647 err4: 1648 xt_unregister_targets(arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg)); 1649 err2: 1650 unregister_pernet_subsys(&arp_tables_net_ops); 1651 err1: 1652 return ret; 1653 } 1654 1655 static void __exit arp_tables_fini(void) 1656 { 1657 nf_unregister_sockopt(&arpt_sockopts); 1658 xt_unregister_targets(arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg)); 1659 unregister_pernet_subsys(&arp_tables_net_ops); 1660 } 1661 1662 EXPORT_SYMBOL(arpt_register_table); 1663 EXPORT_SYMBOL(arpt_unregister_table); 1664 EXPORT_SYMBOL(arpt_do_table); 1665 1666 module_init(arp_tables_init); 1667 module_exit(arp_tables_fini); 1668