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 /* Target might have changed stuff. */ 272 arp = arp_hdr(skb); 273 274 if (verdict == XT_CONTINUE) 275 e = arpt_next_entry(e); 276 else 277 /* Verdict */ 278 break; 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 313 = (struct arpt_entry *)(entry0 + pos); 314 315 if (!(valid_hooks & (1 << hook))) 316 continue; 317 318 /* Set initial back pointer. */ 319 e->counters.pcnt = pos; 320 321 for (;;) { 322 const struct xt_standard_target *t 323 = (void *)arpt_get_target_c(e); 324 int visited = e->comefrom & (1 << hook); 325 326 if (e->comefrom & (1 << NF_ARP_NUMHOOKS)) 327 return 0; 328 329 e->comefrom 330 |= ((1 << hook) | (1 << NF_ARP_NUMHOOKS)); 331 332 /* Unconditional return/END. */ 333 if ((unconditional(e) && 334 (strcmp(t->target.u.user.name, 335 XT_STANDARD_TARGET) == 0) && 336 t->verdict < 0) || visited) { 337 unsigned int oldpos, size; 338 339 if ((strcmp(t->target.u.user.name, 340 XT_STANDARD_TARGET) == 0) && 341 t->verdict < -NF_MAX_VERDICT - 1) 342 return 0; 343 344 /* Return: backtrack through the last 345 * big jump. 346 */ 347 do { 348 e->comefrom ^= (1<<NF_ARP_NUMHOOKS); 349 oldpos = pos; 350 pos = e->counters.pcnt; 351 e->counters.pcnt = 0; 352 353 /* We're at the start. */ 354 if (pos == oldpos) 355 goto next; 356 357 e = (struct arpt_entry *) 358 (entry0 + pos); 359 } while (oldpos == pos + e->next_offset); 360 361 /* Move along one */ 362 size = e->next_offset; 363 e = (struct arpt_entry *) 364 (entry0 + pos + size); 365 if (pos + size >= newinfo->size) 366 return 0; 367 e->counters.pcnt = pos; 368 pos += size; 369 } else { 370 int newpos = t->verdict; 371 372 if (strcmp(t->target.u.user.name, 373 XT_STANDARD_TARGET) == 0 && 374 newpos >= 0) { 375 /* This a jump; chase it. */ 376 if (!xt_find_jump_offset(offsets, newpos, 377 newinfo->number)) 378 return 0; 379 e = (struct arpt_entry *) 380 (entry0 + newpos); 381 } else { 382 /* ... this is a fallthru */ 383 newpos = pos + e->next_offset; 384 if (newpos >= newinfo->size) 385 return 0; 386 } 387 e = (struct arpt_entry *) 388 (entry0 + newpos); 389 e->counters.pcnt = pos; 390 pos = newpos; 391 } 392 } 393 next: ; 394 } 395 return 1; 396 } 397 398 static inline int check_target(struct arpt_entry *e, const char *name) 399 { 400 struct xt_entry_target *t = arpt_get_target(e); 401 struct xt_tgchk_param par = { 402 .table = name, 403 .entryinfo = e, 404 .target = t->u.kernel.target, 405 .targinfo = t->data, 406 .hook_mask = e->comefrom, 407 .family = NFPROTO_ARP, 408 }; 409 410 return xt_check_target(&par, t->u.target_size - sizeof(*t), 0, false); 411 } 412 413 static inline int 414 find_check_entry(struct arpt_entry *e, const char *name, unsigned int size, 415 struct xt_percpu_counter_alloc_state *alloc_state) 416 { 417 struct xt_entry_target *t; 418 struct xt_target *target; 419 int ret; 420 421 if (!xt_percpu_counter_alloc(alloc_state, &e->counters)) 422 return -ENOMEM; 423 424 t = arpt_get_target(e); 425 target = xt_request_find_target(NFPROTO_ARP, t->u.user.name, 426 t->u.user.revision); 427 if (IS_ERR(target)) { 428 ret = PTR_ERR(target); 429 goto out; 430 } 431 t->u.kernel.target = target; 432 433 ret = check_target(e, name); 434 if (ret) 435 goto err; 436 return 0; 437 err: 438 module_put(t->u.kernel.target->me); 439 out: 440 xt_percpu_counter_free(&e->counters); 441 442 return ret; 443 } 444 445 static bool check_underflow(const struct arpt_entry *e) 446 { 447 const struct xt_entry_target *t; 448 unsigned int verdict; 449 450 if (!unconditional(e)) 451 return false; 452 t = arpt_get_target_c(e); 453 if (strcmp(t->u.user.name, XT_STANDARD_TARGET) != 0) 454 return false; 455 verdict = ((struct xt_standard_target *)t)->verdict; 456 verdict = -verdict - 1; 457 return verdict == NF_DROP || verdict == NF_ACCEPT; 458 } 459 460 static inline int check_entry_size_and_hooks(struct arpt_entry *e, 461 struct xt_table_info *newinfo, 462 const unsigned char *base, 463 const unsigned char *limit, 464 const unsigned int *hook_entries, 465 const unsigned int *underflows, 466 unsigned int valid_hooks) 467 { 468 unsigned int h; 469 int err; 470 471 if ((unsigned long)e % __alignof__(struct arpt_entry) != 0 || 472 (unsigned char *)e + sizeof(struct arpt_entry) >= limit || 473 (unsigned char *)e + e->next_offset > limit) 474 return -EINVAL; 475 476 if (e->next_offset 477 < sizeof(struct arpt_entry) + sizeof(struct xt_entry_target)) 478 return -EINVAL; 479 480 if (!arp_checkentry(&e->arp)) 481 return -EINVAL; 482 483 err = xt_check_entry_offsets(e, e->elems, e->target_offset, 484 e->next_offset); 485 if (err) 486 return err; 487 488 /* Check hooks & underflows */ 489 for (h = 0; h < NF_ARP_NUMHOOKS; h++) { 490 if (!(valid_hooks & (1 << h))) 491 continue; 492 if ((unsigned char *)e - base == hook_entries[h]) 493 newinfo->hook_entry[h] = hook_entries[h]; 494 if ((unsigned char *)e - base == underflows[h]) { 495 if (!check_underflow(e)) 496 return -EINVAL; 497 498 newinfo->underflow[h] = underflows[h]; 499 } 500 } 501 502 /* Clear counters and comefrom */ 503 e->counters = ((struct xt_counters) { 0, 0 }); 504 e->comefrom = 0; 505 return 0; 506 } 507 508 static inline void cleanup_entry(struct arpt_entry *e) 509 { 510 struct xt_tgdtor_param par; 511 struct xt_entry_target *t; 512 513 t = arpt_get_target(e); 514 par.target = t->u.kernel.target; 515 par.targinfo = t->data; 516 par.family = NFPROTO_ARP; 517 if (par.target->destroy != NULL) 518 par.target->destroy(&par); 519 module_put(par.target->me); 520 xt_percpu_counter_free(&e->counters); 521 } 522 523 /* Checks and translates the user-supplied table segment (held in 524 * newinfo). 525 */ 526 static int translate_table(struct xt_table_info *newinfo, void *entry0, 527 const struct arpt_replace *repl) 528 { 529 struct xt_percpu_counter_alloc_state alloc_state = { 0 }; 530 struct arpt_entry *iter; 531 unsigned int *offsets; 532 unsigned int i; 533 int ret = 0; 534 535 newinfo->size = repl->size; 536 newinfo->number = repl->num_entries; 537 538 /* Init all hooks to impossible value. */ 539 for (i = 0; i < NF_ARP_NUMHOOKS; i++) { 540 newinfo->hook_entry[i] = 0xFFFFFFFF; 541 newinfo->underflow[i] = 0xFFFFFFFF; 542 } 543 544 offsets = xt_alloc_entry_offsets(newinfo->number); 545 if (!offsets) 546 return -ENOMEM; 547 i = 0; 548 549 /* Walk through entries, checking offsets. */ 550 xt_entry_foreach(iter, entry0, newinfo->size) { 551 ret = check_entry_size_and_hooks(iter, newinfo, entry0, 552 entry0 + repl->size, 553 repl->hook_entry, 554 repl->underflow, 555 repl->valid_hooks); 556 if (ret != 0) 557 goto out_free; 558 if (i < repl->num_entries) 559 offsets[i] = (void *)iter - entry0; 560 ++i; 561 if (strcmp(arpt_get_target(iter)->u.user.name, 562 XT_ERROR_TARGET) == 0) 563 ++newinfo->stacksize; 564 } 565 if (ret != 0) 566 goto out_free; 567 568 ret = -EINVAL; 569 if (i != repl->num_entries) 570 goto out_free; 571 572 /* Check hooks all assigned */ 573 for (i = 0; i < NF_ARP_NUMHOOKS; i++) { 574 /* Only hooks which are valid */ 575 if (!(repl->valid_hooks & (1 << i))) 576 continue; 577 if (newinfo->hook_entry[i] == 0xFFFFFFFF) 578 goto out_free; 579 if (newinfo->underflow[i] == 0xFFFFFFFF) 580 goto out_free; 581 } 582 583 if (!mark_source_chains(newinfo, repl->valid_hooks, entry0, offsets)) { 584 ret = -ELOOP; 585 goto out_free; 586 } 587 kvfree(offsets); 588 589 /* Finally, each sanity check must pass */ 590 i = 0; 591 xt_entry_foreach(iter, entry0, newinfo->size) { 592 ret = find_check_entry(iter, repl->name, repl->size, 593 &alloc_state); 594 if (ret != 0) 595 break; 596 ++i; 597 } 598 599 if (ret != 0) { 600 xt_entry_foreach(iter, entry0, newinfo->size) { 601 if (i-- == 0) 602 break; 603 cleanup_entry(iter); 604 } 605 return ret; 606 } 607 608 return ret; 609 out_free: 610 kvfree(offsets); 611 return ret; 612 } 613 614 static void get_counters(const struct xt_table_info *t, 615 struct xt_counters counters[]) 616 { 617 struct arpt_entry *iter; 618 unsigned int cpu; 619 unsigned int i; 620 621 for_each_possible_cpu(cpu) { 622 seqcount_t *s = &per_cpu(xt_recseq, cpu); 623 624 i = 0; 625 xt_entry_foreach(iter, t->entries, t->size) { 626 struct xt_counters *tmp; 627 u64 bcnt, pcnt; 628 unsigned int start; 629 630 tmp = xt_get_per_cpu_counter(&iter->counters, cpu); 631 do { 632 start = read_seqcount_begin(s); 633 bcnt = tmp->bcnt; 634 pcnt = tmp->pcnt; 635 } while (read_seqcount_retry(s, start)); 636 637 ADD_COUNTER(counters[i], bcnt, pcnt); 638 ++i; 639 } 640 } 641 } 642 643 static struct xt_counters *alloc_counters(const struct xt_table *table) 644 { 645 unsigned int countersize; 646 struct xt_counters *counters; 647 const struct xt_table_info *private = table->private; 648 649 /* We need atomic snapshot of counters: rest doesn't change 650 * (other than comefrom, which userspace doesn't care 651 * about). 652 */ 653 countersize = sizeof(struct xt_counters) * private->number; 654 counters = vzalloc(countersize); 655 656 if (counters == NULL) 657 return ERR_PTR(-ENOMEM); 658 659 get_counters(private, counters); 660 661 return counters; 662 } 663 664 static int copy_entries_to_user(unsigned int total_size, 665 const struct xt_table *table, 666 void __user *userptr) 667 { 668 unsigned int off, num; 669 const struct arpt_entry *e; 670 struct xt_counters *counters; 671 struct xt_table_info *private = table->private; 672 int ret = 0; 673 void *loc_cpu_entry; 674 675 counters = alloc_counters(table); 676 if (IS_ERR(counters)) 677 return PTR_ERR(counters); 678 679 loc_cpu_entry = private->entries; 680 /* ... then copy entire thing ... */ 681 if (copy_to_user(userptr, loc_cpu_entry, total_size) != 0) { 682 ret = -EFAULT; 683 goto free_counters; 684 } 685 686 /* FIXME: use iterator macros --RR */ 687 /* ... then go back and fix counters and names */ 688 for (off = 0, num = 0; off < total_size; off += e->next_offset, num++){ 689 const struct xt_entry_target *t; 690 691 e = (struct arpt_entry *)(loc_cpu_entry + off); 692 if (copy_to_user(userptr + off 693 + offsetof(struct arpt_entry, counters), 694 &counters[num], 695 sizeof(counters[num])) != 0) { 696 ret = -EFAULT; 697 goto free_counters; 698 } 699 700 t = arpt_get_target_c(e); 701 if (copy_to_user(userptr + off + e->target_offset 702 + offsetof(struct xt_entry_target, 703 u.user.name), 704 t->u.kernel.target->name, 705 strlen(t->u.kernel.target->name)+1) != 0) { 706 ret = -EFAULT; 707 goto free_counters; 708 } 709 } 710 711 free_counters: 712 vfree(counters); 713 return ret; 714 } 715 716 #ifdef CONFIG_COMPAT 717 static void compat_standard_from_user(void *dst, const void *src) 718 { 719 int v = *(compat_int_t *)src; 720 721 if (v > 0) 722 v += xt_compat_calc_jump(NFPROTO_ARP, v); 723 memcpy(dst, &v, sizeof(v)); 724 } 725 726 static int compat_standard_to_user(void __user *dst, const void *src) 727 { 728 compat_int_t cv = *(int *)src; 729 730 if (cv > 0) 731 cv -= xt_compat_calc_jump(NFPROTO_ARP, cv); 732 return copy_to_user(dst, &cv, sizeof(cv)) ? -EFAULT : 0; 733 } 734 735 static int compat_calc_entry(const struct arpt_entry *e, 736 const struct xt_table_info *info, 737 const void *base, struct xt_table_info *newinfo) 738 { 739 const struct xt_entry_target *t; 740 unsigned int entry_offset; 741 int off, i, ret; 742 743 off = sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry); 744 entry_offset = (void *)e - base; 745 746 t = arpt_get_target_c(e); 747 off += xt_compat_target_offset(t->u.kernel.target); 748 newinfo->size -= off; 749 ret = xt_compat_add_offset(NFPROTO_ARP, entry_offset, off); 750 if (ret) 751 return ret; 752 753 for (i = 0; i < NF_ARP_NUMHOOKS; i++) { 754 if (info->hook_entry[i] && 755 (e < (struct arpt_entry *)(base + info->hook_entry[i]))) 756 newinfo->hook_entry[i] -= off; 757 if (info->underflow[i] && 758 (e < (struct arpt_entry *)(base + info->underflow[i]))) 759 newinfo->underflow[i] -= off; 760 } 761 return 0; 762 } 763 764 static int compat_table_info(const struct xt_table_info *info, 765 struct xt_table_info *newinfo) 766 { 767 struct arpt_entry *iter; 768 const void *loc_cpu_entry; 769 int ret; 770 771 if (!newinfo || !info) 772 return -EINVAL; 773 774 /* we dont care about newinfo->entries */ 775 memcpy(newinfo, info, offsetof(struct xt_table_info, entries)); 776 newinfo->initial_entries = 0; 777 loc_cpu_entry = info->entries; 778 xt_compat_init_offsets(NFPROTO_ARP, info->number); 779 xt_entry_foreach(iter, loc_cpu_entry, info->size) { 780 ret = compat_calc_entry(iter, info, loc_cpu_entry, newinfo); 781 if (ret != 0) 782 return ret; 783 } 784 return 0; 785 } 786 #endif 787 788 static int get_info(struct net *net, void __user *user, 789 const int *len, int compat) 790 { 791 char name[XT_TABLE_MAXNAMELEN]; 792 struct xt_table *t; 793 int ret; 794 795 if (*len != sizeof(struct arpt_getinfo)) 796 return -EINVAL; 797 798 if (copy_from_user(name, user, sizeof(name)) != 0) 799 return -EFAULT; 800 801 name[XT_TABLE_MAXNAMELEN-1] = '\0'; 802 #ifdef CONFIG_COMPAT 803 if (compat) 804 xt_compat_lock(NFPROTO_ARP); 805 #endif 806 t = try_then_request_module(xt_find_table_lock(net, NFPROTO_ARP, name), 807 "arptable_%s", name); 808 if (t) { 809 struct arpt_getinfo info; 810 const struct xt_table_info *private = t->private; 811 #ifdef CONFIG_COMPAT 812 struct xt_table_info tmp; 813 814 if (compat) { 815 ret = compat_table_info(private, &tmp); 816 xt_compat_flush_offsets(NFPROTO_ARP); 817 private = &tmp; 818 } 819 #endif 820 memset(&info, 0, sizeof(info)); 821 info.valid_hooks = t->valid_hooks; 822 memcpy(info.hook_entry, private->hook_entry, 823 sizeof(info.hook_entry)); 824 memcpy(info.underflow, private->underflow, 825 sizeof(info.underflow)); 826 info.num_entries = private->number; 827 info.size = private->size; 828 strcpy(info.name, name); 829 830 if (copy_to_user(user, &info, *len) != 0) 831 ret = -EFAULT; 832 else 833 ret = 0; 834 xt_table_unlock(t); 835 module_put(t->me); 836 } else 837 ret = -ENOENT; 838 #ifdef CONFIG_COMPAT 839 if (compat) 840 xt_compat_unlock(NFPROTO_ARP); 841 #endif 842 return ret; 843 } 844 845 static int get_entries(struct net *net, struct arpt_get_entries __user *uptr, 846 const int *len) 847 { 848 int ret; 849 struct arpt_get_entries get; 850 struct xt_table *t; 851 852 if (*len < sizeof(get)) 853 return -EINVAL; 854 if (copy_from_user(&get, uptr, sizeof(get)) != 0) 855 return -EFAULT; 856 if (*len != sizeof(struct arpt_get_entries) + get.size) 857 return -EINVAL; 858 859 get.name[sizeof(get.name) - 1] = '\0'; 860 861 t = xt_find_table_lock(net, NFPROTO_ARP, get.name); 862 if (t) { 863 const struct xt_table_info *private = t->private; 864 865 if (get.size == private->size) 866 ret = copy_entries_to_user(private->size, 867 t, uptr->entrytable); 868 else 869 ret = -EAGAIN; 870 871 module_put(t->me); 872 xt_table_unlock(t); 873 } else 874 ret = -ENOENT; 875 876 return ret; 877 } 878 879 static int __do_replace(struct net *net, const char *name, 880 unsigned int valid_hooks, 881 struct xt_table_info *newinfo, 882 unsigned int num_counters, 883 void __user *counters_ptr) 884 { 885 int ret; 886 struct xt_table *t; 887 struct xt_table_info *oldinfo; 888 struct xt_counters *counters; 889 void *loc_cpu_old_entry; 890 struct arpt_entry *iter; 891 892 ret = 0; 893 counters = vzalloc(num_counters * sizeof(struct xt_counters)); 894 if (!counters) { 895 ret = -ENOMEM; 896 goto out; 897 } 898 899 t = try_then_request_module(xt_find_table_lock(net, NFPROTO_ARP, name), 900 "arptable_%s", name); 901 if (!t) { 902 ret = -ENOENT; 903 goto free_newinfo_counters_untrans; 904 } 905 906 /* You lied! */ 907 if (valid_hooks != t->valid_hooks) { 908 ret = -EINVAL; 909 goto put_module; 910 } 911 912 oldinfo = xt_replace_table(t, num_counters, newinfo, &ret); 913 if (!oldinfo) 914 goto put_module; 915 916 /* Update module usage count based on number of rules */ 917 if ((oldinfo->number > oldinfo->initial_entries) || 918 (newinfo->number <= oldinfo->initial_entries)) 919 module_put(t->me); 920 if ((oldinfo->number > oldinfo->initial_entries) && 921 (newinfo->number <= oldinfo->initial_entries)) 922 module_put(t->me); 923 924 /* Get the old counters, and synchronize with replace */ 925 get_counters(oldinfo, counters); 926 927 /* Decrease module usage counts and free resource */ 928 loc_cpu_old_entry = oldinfo->entries; 929 xt_entry_foreach(iter, loc_cpu_old_entry, oldinfo->size) 930 cleanup_entry(iter); 931 932 xt_free_table_info(oldinfo); 933 if (copy_to_user(counters_ptr, counters, 934 sizeof(struct xt_counters) * num_counters) != 0) { 935 /* Silent error, can't fail, new table is already in place */ 936 net_warn_ratelimited("arptables: counters copy to user failed while replacing table\n"); 937 } 938 vfree(counters); 939 xt_table_unlock(t); 940 return ret; 941 942 put_module: 943 module_put(t->me); 944 xt_table_unlock(t); 945 free_newinfo_counters_untrans: 946 vfree(counters); 947 out: 948 return ret; 949 } 950 951 static int do_replace(struct net *net, const void __user *user, 952 unsigned int len) 953 { 954 int ret; 955 struct arpt_replace tmp; 956 struct xt_table_info *newinfo; 957 void *loc_cpu_entry; 958 struct arpt_entry *iter; 959 960 if (copy_from_user(&tmp, user, sizeof(tmp)) != 0) 961 return -EFAULT; 962 963 /* overflow check */ 964 if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters)) 965 return -ENOMEM; 966 if (tmp.num_counters == 0) 967 return -EINVAL; 968 969 tmp.name[sizeof(tmp.name)-1] = 0; 970 971 newinfo = xt_alloc_table_info(tmp.size); 972 if (!newinfo) 973 return -ENOMEM; 974 975 loc_cpu_entry = newinfo->entries; 976 if (copy_from_user(loc_cpu_entry, user + sizeof(tmp), 977 tmp.size) != 0) { 978 ret = -EFAULT; 979 goto free_newinfo; 980 } 981 982 ret = translate_table(newinfo, loc_cpu_entry, &tmp); 983 if (ret != 0) 984 goto free_newinfo; 985 986 ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo, 987 tmp.num_counters, tmp.counters); 988 if (ret) 989 goto free_newinfo_untrans; 990 return 0; 991 992 free_newinfo_untrans: 993 xt_entry_foreach(iter, loc_cpu_entry, newinfo->size) 994 cleanup_entry(iter); 995 free_newinfo: 996 xt_free_table_info(newinfo); 997 return ret; 998 } 999 1000 static int do_add_counters(struct net *net, const void __user *user, 1001 unsigned int len, int compat) 1002 { 1003 unsigned int i; 1004 struct xt_counters_info tmp; 1005 struct xt_counters *paddc; 1006 struct xt_table *t; 1007 const struct xt_table_info *private; 1008 int ret = 0; 1009 struct arpt_entry *iter; 1010 unsigned int addend; 1011 1012 paddc = xt_copy_counters_from_user(user, len, &tmp, compat); 1013 if (IS_ERR(paddc)) 1014 return PTR_ERR(paddc); 1015 1016 t = xt_find_table_lock(net, NFPROTO_ARP, tmp.name); 1017 if (!t) { 1018 ret = -ENOENT; 1019 goto free; 1020 } 1021 1022 local_bh_disable(); 1023 private = t->private; 1024 if (private->number != tmp.num_counters) { 1025 ret = -EINVAL; 1026 goto unlock_up_free; 1027 } 1028 1029 i = 0; 1030 1031 addend = xt_write_recseq_begin(); 1032 xt_entry_foreach(iter, private->entries, private->size) { 1033 struct xt_counters *tmp; 1034 1035 tmp = xt_get_this_cpu_counter(&iter->counters); 1036 ADD_COUNTER(*tmp, paddc[i].bcnt, paddc[i].pcnt); 1037 ++i; 1038 } 1039 xt_write_recseq_end(addend); 1040 unlock_up_free: 1041 local_bh_enable(); 1042 xt_table_unlock(t); 1043 module_put(t->me); 1044 free: 1045 vfree(paddc); 1046 1047 return ret; 1048 } 1049 1050 #ifdef CONFIG_COMPAT 1051 struct compat_arpt_replace { 1052 char name[XT_TABLE_MAXNAMELEN]; 1053 u32 valid_hooks; 1054 u32 num_entries; 1055 u32 size; 1056 u32 hook_entry[NF_ARP_NUMHOOKS]; 1057 u32 underflow[NF_ARP_NUMHOOKS]; 1058 u32 num_counters; 1059 compat_uptr_t counters; 1060 struct compat_arpt_entry entries[0]; 1061 }; 1062 1063 static inline void compat_release_entry(struct compat_arpt_entry *e) 1064 { 1065 struct xt_entry_target *t; 1066 1067 t = compat_arpt_get_target(e); 1068 module_put(t->u.kernel.target->me); 1069 } 1070 1071 static int 1072 check_compat_entry_size_and_hooks(struct compat_arpt_entry *e, 1073 struct xt_table_info *newinfo, 1074 unsigned int *size, 1075 const unsigned char *base, 1076 const unsigned char *limit) 1077 { 1078 struct xt_entry_target *t; 1079 struct xt_target *target; 1080 unsigned int entry_offset; 1081 int ret, off; 1082 1083 if ((unsigned long)e % __alignof__(struct compat_arpt_entry) != 0 || 1084 (unsigned char *)e + sizeof(struct compat_arpt_entry) >= limit || 1085 (unsigned char *)e + e->next_offset > limit) 1086 return -EINVAL; 1087 1088 if (e->next_offset < sizeof(struct compat_arpt_entry) + 1089 sizeof(struct compat_xt_entry_target)) 1090 return -EINVAL; 1091 1092 if (!arp_checkentry(&e->arp)) 1093 return -EINVAL; 1094 1095 ret = xt_compat_check_entry_offsets(e, e->elems, e->target_offset, 1096 e->next_offset); 1097 if (ret) 1098 return ret; 1099 1100 off = sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry); 1101 entry_offset = (void *)e - (void *)base; 1102 1103 t = compat_arpt_get_target(e); 1104 target = xt_request_find_target(NFPROTO_ARP, t->u.user.name, 1105 t->u.user.revision); 1106 if (IS_ERR(target)) { 1107 ret = PTR_ERR(target); 1108 goto out; 1109 } 1110 t->u.kernel.target = target; 1111 1112 off += xt_compat_target_offset(target); 1113 *size += off; 1114 ret = xt_compat_add_offset(NFPROTO_ARP, entry_offset, off); 1115 if (ret) 1116 goto release_target; 1117 1118 return 0; 1119 1120 release_target: 1121 module_put(t->u.kernel.target->me); 1122 out: 1123 return ret; 1124 } 1125 1126 static void 1127 compat_copy_entry_from_user(struct compat_arpt_entry *e, void **dstptr, 1128 unsigned int *size, 1129 struct xt_table_info *newinfo, unsigned char *base) 1130 { 1131 struct xt_entry_target *t; 1132 struct xt_target *target; 1133 struct arpt_entry *de; 1134 unsigned int origsize; 1135 int h; 1136 1137 origsize = *size; 1138 de = (struct arpt_entry *)*dstptr; 1139 memcpy(de, e, sizeof(struct arpt_entry)); 1140 memcpy(&de->counters, &e->counters, sizeof(e->counters)); 1141 1142 *dstptr += sizeof(struct arpt_entry); 1143 *size += sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry); 1144 1145 de->target_offset = e->target_offset - (origsize - *size); 1146 t = compat_arpt_get_target(e); 1147 target = t->u.kernel.target; 1148 xt_compat_target_from_user(t, dstptr, size); 1149 1150 de->next_offset = e->next_offset - (origsize - *size); 1151 for (h = 0; h < NF_ARP_NUMHOOKS; h++) { 1152 if ((unsigned char *)de - base < newinfo->hook_entry[h]) 1153 newinfo->hook_entry[h] -= origsize - *size; 1154 if ((unsigned char *)de - base < newinfo->underflow[h]) 1155 newinfo->underflow[h] -= origsize - *size; 1156 } 1157 } 1158 1159 static int translate_compat_table(struct xt_table_info **pinfo, 1160 void **pentry0, 1161 const struct compat_arpt_replace *compatr) 1162 { 1163 unsigned int i, j; 1164 struct xt_table_info *newinfo, *info; 1165 void *pos, *entry0, *entry1; 1166 struct compat_arpt_entry *iter0; 1167 struct arpt_replace repl; 1168 unsigned int size; 1169 int ret = 0; 1170 1171 info = *pinfo; 1172 entry0 = *pentry0; 1173 size = compatr->size; 1174 info->number = compatr->num_entries; 1175 1176 j = 0; 1177 xt_compat_lock(NFPROTO_ARP); 1178 xt_compat_init_offsets(NFPROTO_ARP, compatr->num_entries); 1179 /* Walk through entries, checking offsets. */ 1180 xt_entry_foreach(iter0, entry0, compatr->size) { 1181 ret = check_compat_entry_size_and_hooks(iter0, info, &size, 1182 entry0, 1183 entry0 + compatr->size); 1184 if (ret != 0) 1185 goto out_unlock; 1186 ++j; 1187 } 1188 1189 ret = -EINVAL; 1190 if (j != compatr->num_entries) 1191 goto out_unlock; 1192 1193 ret = -ENOMEM; 1194 newinfo = xt_alloc_table_info(size); 1195 if (!newinfo) 1196 goto out_unlock; 1197 1198 newinfo->number = compatr->num_entries; 1199 for (i = 0; i < NF_ARP_NUMHOOKS; i++) { 1200 newinfo->hook_entry[i] = compatr->hook_entry[i]; 1201 newinfo->underflow[i] = compatr->underflow[i]; 1202 } 1203 entry1 = newinfo->entries; 1204 pos = entry1; 1205 size = compatr->size; 1206 xt_entry_foreach(iter0, entry0, compatr->size) 1207 compat_copy_entry_from_user(iter0, &pos, &size, 1208 newinfo, entry1); 1209 1210 /* all module references in entry0 are now gone */ 1211 1212 xt_compat_flush_offsets(NFPROTO_ARP); 1213 xt_compat_unlock(NFPROTO_ARP); 1214 1215 memcpy(&repl, compatr, sizeof(*compatr)); 1216 1217 for (i = 0; i < NF_ARP_NUMHOOKS; i++) { 1218 repl.hook_entry[i] = newinfo->hook_entry[i]; 1219 repl.underflow[i] = newinfo->underflow[i]; 1220 } 1221 1222 repl.num_counters = 0; 1223 repl.counters = NULL; 1224 repl.size = newinfo->size; 1225 ret = translate_table(newinfo, entry1, &repl); 1226 if (ret) 1227 goto free_newinfo; 1228 1229 *pinfo = newinfo; 1230 *pentry0 = entry1; 1231 xt_free_table_info(info); 1232 return 0; 1233 1234 free_newinfo: 1235 xt_free_table_info(newinfo); 1236 return ret; 1237 out_unlock: 1238 xt_compat_flush_offsets(NFPROTO_ARP); 1239 xt_compat_unlock(NFPROTO_ARP); 1240 xt_entry_foreach(iter0, entry0, compatr->size) { 1241 if (j-- == 0) 1242 break; 1243 compat_release_entry(iter0); 1244 } 1245 return ret; 1246 } 1247 1248 static int compat_do_replace(struct net *net, void __user *user, 1249 unsigned int len) 1250 { 1251 int ret; 1252 struct compat_arpt_replace tmp; 1253 struct xt_table_info *newinfo; 1254 void *loc_cpu_entry; 1255 struct arpt_entry *iter; 1256 1257 if (copy_from_user(&tmp, user, sizeof(tmp)) != 0) 1258 return -EFAULT; 1259 1260 /* overflow check */ 1261 if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters)) 1262 return -ENOMEM; 1263 if (tmp.num_counters == 0) 1264 return -EINVAL; 1265 1266 tmp.name[sizeof(tmp.name)-1] = 0; 1267 1268 newinfo = xt_alloc_table_info(tmp.size); 1269 if (!newinfo) 1270 return -ENOMEM; 1271 1272 loc_cpu_entry = newinfo->entries; 1273 if (copy_from_user(loc_cpu_entry, user + sizeof(tmp), tmp.size) != 0) { 1274 ret = -EFAULT; 1275 goto free_newinfo; 1276 } 1277 1278 ret = translate_compat_table(&newinfo, &loc_cpu_entry, &tmp); 1279 if (ret != 0) 1280 goto free_newinfo; 1281 1282 ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo, 1283 tmp.num_counters, compat_ptr(tmp.counters)); 1284 if (ret) 1285 goto free_newinfo_untrans; 1286 return 0; 1287 1288 free_newinfo_untrans: 1289 xt_entry_foreach(iter, loc_cpu_entry, newinfo->size) 1290 cleanup_entry(iter); 1291 free_newinfo: 1292 xt_free_table_info(newinfo); 1293 return ret; 1294 } 1295 1296 static int compat_do_arpt_set_ctl(struct sock *sk, int cmd, void __user *user, 1297 unsigned int len) 1298 { 1299 int ret; 1300 1301 if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN)) 1302 return -EPERM; 1303 1304 switch (cmd) { 1305 case ARPT_SO_SET_REPLACE: 1306 ret = compat_do_replace(sock_net(sk), user, len); 1307 break; 1308 1309 case ARPT_SO_SET_ADD_COUNTERS: 1310 ret = do_add_counters(sock_net(sk), user, len, 1); 1311 break; 1312 1313 default: 1314 ret = -EINVAL; 1315 } 1316 1317 return ret; 1318 } 1319 1320 static int compat_copy_entry_to_user(struct arpt_entry *e, void __user **dstptr, 1321 compat_uint_t *size, 1322 struct xt_counters *counters, 1323 unsigned int i) 1324 { 1325 struct xt_entry_target *t; 1326 struct compat_arpt_entry __user *ce; 1327 u_int16_t target_offset, next_offset; 1328 compat_uint_t origsize; 1329 int ret; 1330 1331 origsize = *size; 1332 ce = (struct compat_arpt_entry __user *)*dstptr; 1333 if (copy_to_user(ce, e, sizeof(struct arpt_entry)) != 0 || 1334 copy_to_user(&ce->counters, &counters[i], 1335 sizeof(counters[i])) != 0) 1336 return -EFAULT; 1337 1338 *dstptr += sizeof(struct compat_arpt_entry); 1339 *size -= sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry); 1340 1341 target_offset = e->target_offset - (origsize - *size); 1342 1343 t = arpt_get_target(e); 1344 ret = xt_compat_target_to_user(t, dstptr, size); 1345 if (ret) 1346 return ret; 1347 next_offset = e->next_offset - (origsize - *size); 1348 if (put_user(target_offset, &ce->target_offset) != 0 || 1349 put_user(next_offset, &ce->next_offset) != 0) 1350 return -EFAULT; 1351 return 0; 1352 } 1353 1354 static int compat_copy_entries_to_user(unsigned int total_size, 1355 struct xt_table *table, 1356 void __user *userptr) 1357 { 1358 struct xt_counters *counters; 1359 const struct xt_table_info *private = table->private; 1360 void __user *pos; 1361 unsigned int size; 1362 int ret = 0; 1363 unsigned int i = 0; 1364 struct arpt_entry *iter; 1365 1366 counters = alloc_counters(table); 1367 if (IS_ERR(counters)) 1368 return PTR_ERR(counters); 1369 1370 pos = userptr; 1371 size = total_size; 1372 xt_entry_foreach(iter, private->entries, total_size) { 1373 ret = compat_copy_entry_to_user(iter, &pos, 1374 &size, counters, i++); 1375 if (ret != 0) 1376 break; 1377 } 1378 vfree(counters); 1379 return ret; 1380 } 1381 1382 struct compat_arpt_get_entries { 1383 char name[XT_TABLE_MAXNAMELEN]; 1384 compat_uint_t size; 1385 struct compat_arpt_entry entrytable[0]; 1386 }; 1387 1388 static int compat_get_entries(struct net *net, 1389 struct compat_arpt_get_entries __user *uptr, 1390 int *len) 1391 { 1392 int ret; 1393 struct compat_arpt_get_entries get; 1394 struct xt_table *t; 1395 1396 if (*len < sizeof(get)) 1397 return -EINVAL; 1398 if (copy_from_user(&get, uptr, sizeof(get)) != 0) 1399 return -EFAULT; 1400 if (*len != sizeof(struct compat_arpt_get_entries) + get.size) 1401 return -EINVAL; 1402 1403 get.name[sizeof(get.name) - 1] = '\0'; 1404 1405 xt_compat_lock(NFPROTO_ARP); 1406 t = xt_find_table_lock(net, NFPROTO_ARP, get.name); 1407 if (t) { 1408 const struct xt_table_info *private = t->private; 1409 struct xt_table_info info; 1410 1411 ret = compat_table_info(private, &info); 1412 if (!ret && get.size == info.size) { 1413 ret = compat_copy_entries_to_user(private->size, 1414 t, uptr->entrytable); 1415 } else if (!ret) 1416 ret = -EAGAIN; 1417 1418 xt_compat_flush_offsets(NFPROTO_ARP); 1419 module_put(t->me); 1420 xt_table_unlock(t); 1421 } else 1422 ret = -ENOENT; 1423 1424 xt_compat_unlock(NFPROTO_ARP); 1425 return ret; 1426 } 1427 1428 static int do_arpt_get_ctl(struct sock *, int, void __user *, int *); 1429 1430 static int compat_do_arpt_get_ctl(struct sock *sk, int cmd, void __user *user, 1431 int *len) 1432 { 1433 int ret; 1434 1435 if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN)) 1436 return -EPERM; 1437 1438 switch (cmd) { 1439 case ARPT_SO_GET_INFO: 1440 ret = get_info(sock_net(sk), user, len, 1); 1441 break; 1442 case ARPT_SO_GET_ENTRIES: 1443 ret = compat_get_entries(sock_net(sk), user, len); 1444 break; 1445 default: 1446 ret = do_arpt_get_ctl(sk, cmd, user, len); 1447 } 1448 return ret; 1449 } 1450 #endif 1451 1452 static int do_arpt_set_ctl(struct sock *sk, int cmd, void __user *user, unsigned int len) 1453 { 1454 int ret; 1455 1456 if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN)) 1457 return -EPERM; 1458 1459 switch (cmd) { 1460 case ARPT_SO_SET_REPLACE: 1461 ret = do_replace(sock_net(sk), user, len); 1462 break; 1463 1464 case ARPT_SO_SET_ADD_COUNTERS: 1465 ret = do_add_counters(sock_net(sk), user, len, 0); 1466 break; 1467 1468 default: 1469 ret = -EINVAL; 1470 } 1471 1472 return ret; 1473 } 1474 1475 static int do_arpt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len) 1476 { 1477 int ret; 1478 1479 if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN)) 1480 return -EPERM; 1481 1482 switch (cmd) { 1483 case ARPT_SO_GET_INFO: 1484 ret = get_info(sock_net(sk), user, len, 0); 1485 break; 1486 1487 case ARPT_SO_GET_ENTRIES: 1488 ret = get_entries(sock_net(sk), user, len); 1489 break; 1490 1491 case ARPT_SO_GET_REVISION_TARGET: { 1492 struct xt_get_revision rev; 1493 1494 if (*len != sizeof(rev)) { 1495 ret = -EINVAL; 1496 break; 1497 } 1498 if (copy_from_user(&rev, user, sizeof(rev)) != 0) { 1499 ret = -EFAULT; 1500 break; 1501 } 1502 rev.name[sizeof(rev.name)-1] = 0; 1503 1504 try_then_request_module(xt_find_revision(NFPROTO_ARP, rev.name, 1505 rev.revision, 1, &ret), 1506 "arpt_%s", rev.name); 1507 break; 1508 } 1509 1510 default: 1511 ret = -EINVAL; 1512 } 1513 1514 return ret; 1515 } 1516 1517 static void __arpt_unregister_table(struct xt_table *table) 1518 { 1519 struct xt_table_info *private; 1520 void *loc_cpu_entry; 1521 struct module *table_owner = table->me; 1522 struct arpt_entry *iter; 1523 1524 private = xt_unregister_table(table); 1525 1526 /* Decrease module usage counts and free resources */ 1527 loc_cpu_entry = private->entries; 1528 xt_entry_foreach(iter, loc_cpu_entry, private->size) 1529 cleanup_entry(iter); 1530 if (private->number > private->initial_entries) 1531 module_put(table_owner); 1532 xt_free_table_info(private); 1533 } 1534 1535 int arpt_register_table(struct net *net, 1536 const struct xt_table *table, 1537 const struct arpt_replace *repl, 1538 const struct nf_hook_ops *ops, 1539 struct xt_table **res) 1540 { 1541 int ret; 1542 struct xt_table_info *newinfo; 1543 struct xt_table_info bootstrap = {0}; 1544 void *loc_cpu_entry; 1545 struct xt_table *new_table; 1546 1547 newinfo = xt_alloc_table_info(repl->size); 1548 if (!newinfo) 1549 return -ENOMEM; 1550 1551 loc_cpu_entry = newinfo->entries; 1552 memcpy(loc_cpu_entry, repl->entries, repl->size); 1553 1554 ret = translate_table(newinfo, loc_cpu_entry, repl); 1555 if (ret != 0) 1556 goto out_free; 1557 1558 new_table = xt_register_table(net, table, &bootstrap, newinfo); 1559 if (IS_ERR(new_table)) { 1560 ret = PTR_ERR(new_table); 1561 goto out_free; 1562 } 1563 1564 /* set res now, will see skbs right after nf_register_net_hooks */ 1565 WRITE_ONCE(*res, new_table); 1566 1567 ret = nf_register_net_hooks(net, ops, hweight32(table->valid_hooks)); 1568 if (ret != 0) { 1569 __arpt_unregister_table(new_table); 1570 *res = NULL; 1571 } 1572 1573 return ret; 1574 1575 out_free: 1576 xt_free_table_info(newinfo); 1577 return ret; 1578 } 1579 1580 void arpt_unregister_table(struct net *net, struct xt_table *table, 1581 const struct nf_hook_ops *ops) 1582 { 1583 nf_unregister_net_hooks(net, ops, hweight32(table->valid_hooks)); 1584 __arpt_unregister_table(table); 1585 } 1586 1587 /* The built-in targets: standard (NULL) and error. */ 1588 static struct xt_target arpt_builtin_tg[] __read_mostly = { 1589 { 1590 .name = XT_STANDARD_TARGET, 1591 .targetsize = sizeof(int), 1592 .family = NFPROTO_ARP, 1593 #ifdef CONFIG_COMPAT 1594 .compatsize = sizeof(compat_int_t), 1595 .compat_from_user = compat_standard_from_user, 1596 .compat_to_user = compat_standard_to_user, 1597 #endif 1598 }, 1599 { 1600 .name = XT_ERROR_TARGET, 1601 .target = arpt_error, 1602 .targetsize = XT_FUNCTION_MAXNAMELEN, 1603 .family = NFPROTO_ARP, 1604 }, 1605 }; 1606 1607 static struct nf_sockopt_ops arpt_sockopts = { 1608 .pf = PF_INET, 1609 .set_optmin = ARPT_BASE_CTL, 1610 .set_optmax = ARPT_SO_SET_MAX+1, 1611 .set = do_arpt_set_ctl, 1612 #ifdef CONFIG_COMPAT 1613 .compat_set = compat_do_arpt_set_ctl, 1614 #endif 1615 .get_optmin = ARPT_BASE_CTL, 1616 .get_optmax = ARPT_SO_GET_MAX+1, 1617 .get = do_arpt_get_ctl, 1618 #ifdef CONFIG_COMPAT 1619 .compat_get = compat_do_arpt_get_ctl, 1620 #endif 1621 .owner = THIS_MODULE, 1622 }; 1623 1624 static int __net_init arp_tables_net_init(struct net *net) 1625 { 1626 return xt_proto_init(net, NFPROTO_ARP); 1627 } 1628 1629 static void __net_exit arp_tables_net_exit(struct net *net) 1630 { 1631 xt_proto_fini(net, NFPROTO_ARP); 1632 } 1633 1634 static struct pernet_operations arp_tables_net_ops = { 1635 .init = arp_tables_net_init, 1636 .exit = arp_tables_net_exit, 1637 }; 1638 1639 static int __init arp_tables_init(void) 1640 { 1641 int ret; 1642 1643 ret = register_pernet_subsys(&arp_tables_net_ops); 1644 if (ret < 0) 1645 goto err1; 1646 1647 /* No one else will be downing sem now, so we won't sleep */ 1648 ret = xt_register_targets(arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg)); 1649 if (ret < 0) 1650 goto err2; 1651 1652 /* Register setsockopt */ 1653 ret = nf_register_sockopt(&arpt_sockopts); 1654 if (ret < 0) 1655 goto err4; 1656 1657 pr_info("arp_tables: (C) 2002 David S. Miller\n"); 1658 return 0; 1659 1660 err4: 1661 xt_unregister_targets(arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg)); 1662 err2: 1663 unregister_pernet_subsys(&arp_tables_net_ops); 1664 err1: 1665 return ret; 1666 } 1667 1668 static void __exit arp_tables_fini(void) 1669 { 1670 nf_unregister_sockopt(&arpt_sockopts); 1671 xt_unregister_targets(arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg)); 1672 unregister_pernet_subsys(&arp_tables_net_ops); 1673 } 1674 1675 EXPORT_SYMBOL(arpt_register_table); 1676 EXPORT_SYMBOL(arpt_unregister_table); 1677 EXPORT_SYMBOL(arpt_do_table); 1678 1679 module_init(arp_tables_init); 1680 module_exit(arp_tables_fini); 1681