1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Packet matching code for ARP packets. 4 * 5 * Based heavily, if not almost entirely, upon ip_tables.c framework. 6 * 7 * Some ARP specific bits are: 8 * 9 * Copyright (C) 2002 David S. Miller (davem@redhat.com) 10 * Copyright (C) 2006-2009 Patrick McHardy <kaber@trash.net> 11 * 12 */ 13 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 14 #include <linux/kernel.h> 15 #include <linux/skbuff.h> 16 #include <linux/netdevice.h> 17 #include <linux/capability.h> 18 #include <linux/if_arp.h> 19 #include <linux/kmod.h> 20 #include <linux/vmalloc.h> 21 #include <linux/proc_fs.h> 22 #include <linux/module.h> 23 #include <linux/init.h> 24 #include <linux/mutex.h> 25 #include <linux/err.h> 26 #include <net/compat.h> 27 #include <net/sock.h> 28 #include <linux/uaccess.h> 29 30 #include <linux/netfilter/x_tables.h> 31 #include <linux/netfilter_arp/arp_tables.h> 32 #include "../../netfilter/xt_repldata.h" 33 34 MODULE_LICENSE("GPL"); 35 MODULE_AUTHOR("David S. Miller <davem@redhat.com>"); 36 MODULE_DESCRIPTION("arptables core"); 37 38 void *arpt_alloc_initial_table(const struct xt_table *info) 39 { 40 return xt_alloc_initial_table(arpt, ARPT); 41 } 42 EXPORT_SYMBOL_GPL(arpt_alloc_initial_table); 43 44 static inline int arp_devaddr_compare(const struct arpt_devaddr_info *ap, 45 const char *hdr_addr, int len) 46 { 47 int i, ret; 48 49 if (len > ARPT_DEV_ADDR_LEN_MAX) 50 len = ARPT_DEV_ADDR_LEN_MAX; 51 52 ret = 0; 53 for (i = 0; i < len; i++) 54 ret |= (hdr_addr[i] ^ ap->addr[i]) & ap->mask[i]; 55 56 return ret != 0; 57 } 58 59 /* 60 * Unfortunately, _b and _mask are not aligned to an int (or long int) 61 * Some arches dont care, unrolling the loop is a win on them. 62 * For other arches, we only have a 16bit alignement. 63 */ 64 static unsigned long ifname_compare(const char *_a, const char *_b, const char *_mask) 65 { 66 #ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS 67 unsigned long ret = ifname_compare_aligned(_a, _b, _mask); 68 #else 69 unsigned long ret = 0; 70 const u16 *a = (const u16 *)_a; 71 const u16 *b = (const u16 *)_b; 72 const u16 *mask = (const u16 *)_mask; 73 int i; 74 75 for (i = 0; i < IFNAMSIZ/sizeof(u16); i++) 76 ret |= (a[i] ^ b[i]) & mask[i]; 77 #endif 78 return ret; 79 } 80 81 /* Returns whether packet matches rule or not. */ 82 static inline int arp_packet_match(const struct arphdr *arphdr, 83 struct net_device *dev, 84 const char *indev, 85 const char *outdev, 86 const struct arpt_arp *arpinfo) 87 { 88 const char *arpptr = (char *)(arphdr + 1); 89 const char *src_devaddr, *tgt_devaddr; 90 __be32 src_ipaddr, tgt_ipaddr; 91 long ret; 92 93 if (NF_INVF(arpinfo, ARPT_INV_ARPOP, 94 (arphdr->ar_op & arpinfo->arpop_mask) != arpinfo->arpop)) 95 return 0; 96 97 if (NF_INVF(arpinfo, ARPT_INV_ARPHRD, 98 (arphdr->ar_hrd & arpinfo->arhrd_mask) != arpinfo->arhrd)) 99 return 0; 100 101 if (NF_INVF(arpinfo, ARPT_INV_ARPPRO, 102 (arphdr->ar_pro & arpinfo->arpro_mask) != arpinfo->arpro)) 103 return 0; 104 105 if (NF_INVF(arpinfo, ARPT_INV_ARPHLN, 106 (arphdr->ar_hln & arpinfo->arhln_mask) != arpinfo->arhln)) 107 return 0; 108 109 src_devaddr = arpptr; 110 arpptr += dev->addr_len; 111 memcpy(&src_ipaddr, arpptr, sizeof(u32)); 112 arpptr += sizeof(u32); 113 tgt_devaddr = arpptr; 114 arpptr += dev->addr_len; 115 memcpy(&tgt_ipaddr, arpptr, sizeof(u32)); 116 117 if (NF_INVF(arpinfo, ARPT_INV_SRCDEVADDR, 118 arp_devaddr_compare(&arpinfo->src_devaddr, src_devaddr, 119 dev->addr_len)) || 120 NF_INVF(arpinfo, ARPT_INV_TGTDEVADDR, 121 arp_devaddr_compare(&arpinfo->tgt_devaddr, tgt_devaddr, 122 dev->addr_len))) 123 return 0; 124 125 if (NF_INVF(arpinfo, ARPT_INV_SRCIP, 126 (src_ipaddr & arpinfo->smsk.s_addr) != arpinfo->src.s_addr) || 127 NF_INVF(arpinfo, ARPT_INV_TGTIP, 128 (tgt_ipaddr & arpinfo->tmsk.s_addr) != arpinfo->tgt.s_addr)) 129 return 0; 130 131 /* Look for ifname matches. */ 132 ret = ifname_compare(indev, arpinfo->iniface, arpinfo->iniface_mask); 133 134 if (NF_INVF(arpinfo, ARPT_INV_VIA_IN, ret != 0)) 135 return 0; 136 137 ret = ifname_compare(outdev, arpinfo->outiface, arpinfo->outiface_mask); 138 139 if (NF_INVF(arpinfo, ARPT_INV_VIA_OUT, ret != 0)) 140 return 0; 141 142 return 1; 143 } 144 145 static inline int arp_checkentry(const struct arpt_arp *arp) 146 { 147 if (arp->flags & ~ARPT_F_MASK) 148 return 0; 149 if (arp->invflags & ~ARPT_INV_MASK) 150 return 0; 151 152 return 1; 153 } 154 155 static unsigned int 156 arpt_error(struct sk_buff *skb, const struct xt_action_param *par) 157 { 158 net_err_ratelimited("arp_tables: error: '%s'\n", 159 (const char *)par->targinfo); 160 161 return NF_DROP; 162 } 163 164 static inline const struct xt_entry_target * 165 arpt_get_target_c(const struct arpt_entry *e) 166 { 167 return arpt_get_target((struct arpt_entry *)e); 168 } 169 170 static inline struct arpt_entry * 171 get_entry(const void *base, unsigned int offset) 172 { 173 return (struct arpt_entry *)(base + offset); 174 } 175 176 static inline 177 struct arpt_entry *arpt_next_entry(const struct arpt_entry *entry) 178 { 179 return (void *)entry + entry->next_offset; 180 } 181 182 unsigned int arpt_do_table(struct sk_buff *skb, 183 const struct nf_hook_state *state, 184 struct xt_table *table) 185 { 186 unsigned int hook = state->hook; 187 static const char nulldevname[IFNAMSIZ] __attribute__((aligned(sizeof(long)))); 188 unsigned int verdict = NF_DROP; 189 const struct arphdr *arp; 190 struct arpt_entry *e, **jumpstack; 191 const char *indev, *outdev; 192 const void *table_base; 193 unsigned int cpu, stackidx = 0; 194 const struct xt_table_info *private; 195 struct xt_action_param acpar; 196 unsigned int addend; 197 198 if (!pskb_may_pull(skb, arp_hdr_len(skb->dev))) 199 return NF_DROP; 200 201 indev = state->in ? state->in->name : nulldevname; 202 outdev = state->out ? state->out->name : nulldevname; 203 204 local_bh_disable(); 205 addend = xt_write_recseq_begin(); 206 private = READ_ONCE(table->private); /* Address dependency. */ 207 cpu = smp_processor_id(); 208 table_base = private->entries; 209 jumpstack = (struct arpt_entry **)private->jumpstack[cpu]; 210 211 /* No TEE support for arptables, so no need to switch to alternate 212 * stack. All targets that reenter must return absolute verdicts. 213 */ 214 e = get_entry(table_base, private->hook_entry[hook]); 215 216 acpar.state = state; 217 acpar.hotdrop = false; 218 219 arp = arp_hdr(skb); 220 do { 221 const struct xt_entry_target *t; 222 struct xt_counters *counter; 223 224 if (!arp_packet_match(arp, skb->dev, indev, outdev, &e->arp)) { 225 e = arpt_next_entry(e); 226 continue; 227 } 228 229 counter = xt_get_this_cpu_counter(&e->counters); 230 ADD_COUNTER(*counter, arp_hdr_len(skb->dev), 1); 231 232 t = arpt_get_target_c(e); 233 234 /* Standard target? */ 235 if (!t->u.kernel.target->target) { 236 int v; 237 238 v = ((struct xt_standard_target *)t)->verdict; 239 if (v < 0) { 240 /* Pop from stack? */ 241 if (v != XT_RETURN) { 242 verdict = (unsigned int)(-v) - 1; 243 break; 244 } 245 if (stackidx == 0) { 246 e = get_entry(table_base, 247 private->underflow[hook]); 248 } else { 249 e = jumpstack[--stackidx]; 250 e = arpt_next_entry(e); 251 } 252 continue; 253 } 254 if (table_base + v 255 != arpt_next_entry(e)) { 256 if (unlikely(stackidx >= private->stacksize)) { 257 verdict = NF_DROP; 258 break; 259 } 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 /* Return: backtrack through the last 339 * big jump. 340 */ 341 do { 342 e->comefrom ^= (1<<NF_ARP_NUMHOOKS); 343 oldpos = pos; 344 pos = e->counters.pcnt; 345 e->counters.pcnt = 0; 346 347 /* We're at the start. */ 348 if (pos == oldpos) 349 goto next; 350 351 e = entry0 + pos; 352 } while (oldpos == pos + e->next_offset); 353 354 /* Move along one */ 355 size = e->next_offset; 356 e = entry0 + pos + size; 357 if (pos + size >= newinfo->size) 358 return 0; 359 e->counters.pcnt = pos; 360 pos += size; 361 } else { 362 int newpos = t->verdict; 363 364 if (strcmp(t->target.u.user.name, 365 XT_STANDARD_TARGET) == 0 && 366 newpos >= 0) { 367 /* This a jump; chase it. */ 368 if (!xt_find_jump_offset(offsets, newpos, 369 newinfo->number)) 370 return 0; 371 } else { 372 /* ... this is a fallthru */ 373 newpos = pos + e->next_offset; 374 if (newpos >= newinfo->size) 375 return 0; 376 } 377 e = entry0 + newpos; 378 e->counters.pcnt = pos; 379 pos = newpos; 380 } 381 } 382 next: ; 383 } 384 return 1; 385 } 386 387 static int check_target(struct arpt_entry *e, struct net *net, const char *name) 388 { 389 struct xt_entry_target *t = arpt_get_target(e); 390 struct xt_tgchk_param par = { 391 .net = net, 392 .table = name, 393 .entryinfo = e, 394 .target = t->u.kernel.target, 395 .targinfo = t->data, 396 .hook_mask = e->comefrom, 397 .family = NFPROTO_ARP, 398 }; 399 400 return xt_check_target(&par, t->u.target_size - sizeof(*t), 0, false); 401 } 402 403 static int 404 find_check_entry(struct arpt_entry *e, struct net *net, const char *name, 405 unsigned int size, 406 struct xt_percpu_counter_alloc_state *alloc_state) 407 { 408 struct xt_entry_target *t; 409 struct xt_target *target; 410 int ret; 411 412 if (!xt_percpu_counter_alloc(alloc_state, &e->counters)) 413 return -ENOMEM; 414 415 t = arpt_get_target(e); 416 target = xt_request_find_target(NFPROTO_ARP, t->u.user.name, 417 t->u.user.revision); 418 if (IS_ERR(target)) { 419 ret = PTR_ERR(target); 420 goto out; 421 } 422 t->u.kernel.target = target; 423 424 ret = check_target(e, net, name); 425 if (ret) 426 goto err; 427 return 0; 428 err: 429 module_put(t->u.kernel.target->me); 430 out: 431 xt_percpu_counter_free(&e->counters); 432 433 return ret; 434 } 435 436 static bool check_underflow(const struct arpt_entry *e) 437 { 438 const struct xt_entry_target *t; 439 unsigned int verdict; 440 441 if (!unconditional(e)) 442 return false; 443 t = arpt_get_target_c(e); 444 if (strcmp(t->u.user.name, XT_STANDARD_TARGET) != 0) 445 return false; 446 verdict = ((struct xt_standard_target *)t)->verdict; 447 verdict = -verdict - 1; 448 return verdict == NF_DROP || verdict == NF_ACCEPT; 449 } 450 451 static inline int check_entry_size_and_hooks(struct arpt_entry *e, 452 struct xt_table_info *newinfo, 453 const unsigned char *base, 454 const unsigned char *limit, 455 const unsigned int *hook_entries, 456 const unsigned int *underflows, 457 unsigned int valid_hooks) 458 { 459 unsigned int h; 460 int err; 461 462 if ((unsigned long)e % __alignof__(struct arpt_entry) != 0 || 463 (unsigned char *)e + sizeof(struct arpt_entry) >= limit || 464 (unsigned char *)e + e->next_offset > limit) 465 return -EINVAL; 466 467 if (e->next_offset 468 < sizeof(struct arpt_entry) + sizeof(struct xt_entry_target)) 469 return -EINVAL; 470 471 if (!arp_checkentry(&e->arp)) 472 return -EINVAL; 473 474 err = xt_check_entry_offsets(e, e->elems, e->target_offset, 475 e->next_offset); 476 if (err) 477 return err; 478 479 /* Check hooks & underflows */ 480 for (h = 0; h < NF_ARP_NUMHOOKS; h++) { 481 if (!(valid_hooks & (1 << h))) 482 continue; 483 if ((unsigned char *)e - base == hook_entries[h]) 484 newinfo->hook_entry[h] = hook_entries[h]; 485 if ((unsigned char *)e - base == underflows[h]) { 486 if (!check_underflow(e)) 487 return -EINVAL; 488 489 newinfo->underflow[h] = underflows[h]; 490 } 491 } 492 493 /* Clear counters and comefrom */ 494 e->counters = ((struct xt_counters) { 0, 0 }); 495 e->comefrom = 0; 496 return 0; 497 } 498 499 static void cleanup_entry(struct arpt_entry *e, struct net *net) 500 { 501 struct xt_tgdtor_param par; 502 struct xt_entry_target *t; 503 504 t = arpt_get_target(e); 505 par.net = net; 506 par.target = t->u.kernel.target; 507 par.targinfo = t->data; 508 par.family = NFPROTO_ARP; 509 if (par.target->destroy != NULL) 510 par.target->destroy(&par); 511 module_put(par.target->me); 512 xt_percpu_counter_free(&e->counters); 513 } 514 515 /* Checks and translates the user-supplied table segment (held in 516 * newinfo). 517 */ 518 static int translate_table(struct net *net, 519 struct xt_table_info *newinfo, 520 void *entry0, 521 const struct arpt_replace *repl) 522 { 523 struct xt_percpu_counter_alloc_state alloc_state = { 0 }; 524 struct arpt_entry *iter; 525 unsigned int *offsets; 526 unsigned int i; 527 int ret = 0; 528 529 newinfo->size = repl->size; 530 newinfo->number = repl->num_entries; 531 532 /* Init all hooks to impossible value. */ 533 for (i = 0; i < NF_ARP_NUMHOOKS; i++) { 534 newinfo->hook_entry[i] = 0xFFFFFFFF; 535 newinfo->underflow[i] = 0xFFFFFFFF; 536 } 537 538 offsets = xt_alloc_entry_offsets(newinfo->number); 539 if (!offsets) 540 return -ENOMEM; 541 i = 0; 542 543 /* Walk through entries, checking offsets. */ 544 xt_entry_foreach(iter, entry0, newinfo->size) { 545 ret = check_entry_size_and_hooks(iter, newinfo, entry0, 546 entry0 + repl->size, 547 repl->hook_entry, 548 repl->underflow, 549 repl->valid_hooks); 550 if (ret != 0) 551 goto out_free; 552 if (i < repl->num_entries) 553 offsets[i] = (void *)iter - entry0; 554 ++i; 555 if (strcmp(arpt_get_target(iter)->u.user.name, 556 XT_ERROR_TARGET) == 0) 557 ++newinfo->stacksize; 558 } 559 560 ret = -EINVAL; 561 if (i != repl->num_entries) 562 goto out_free; 563 564 ret = xt_check_table_hooks(newinfo, repl->valid_hooks); 565 if (ret) 566 goto out_free; 567 568 if (!mark_source_chains(newinfo, repl->valid_hooks, entry0, offsets)) { 569 ret = -ELOOP; 570 goto out_free; 571 } 572 kvfree(offsets); 573 574 /* Finally, each sanity check must pass */ 575 i = 0; 576 xt_entry_foreach(iter, entry0, newinfo->size) { 577 ret = find_check_entry(iter, net, repl->name, repl->size, 578 &alloc_state); 579 if (ret != 0) 580 break; 581 ++i; 582 } 583 584 if (ret != 0) { 585 xt_entry_foreach(iter, entry0, newinfo->size) { 586 if (i-- == 0) 587 break; 588 cleanup_entry(iter, net); 589 } 590 return ret; 591 } 592 593 return ret; 594 out_free: 595 kvfree(offsets); 596 return ret; 597 } 598 599 static void get_counters(const struct xt_table_info *t, 600 struct xt_counters counters[]) 601 { 602 struct arpt_entry *iter; 603 unsigned int cpu; 604 unsigned int i; 605 606 for_each_possible_cpu(cpu) { 607 seqcount_t *s = &per_cpu(xt_recseq, cpu); 608 609 i = 0; 610 xt_entry_foreach(iter, t->entries, t->size) { 611 struct xt_counters *tmp; 612 u64 bcnt, pcnt; 613 unsigned int start; 614 615 tmp = xt_get_per_cpu_counter(&iter->counters, cpu); 616 do { 617 start = read_seqcount_begin(s); 618 bcnt = tmp->bcnt; 619 pcnt = tmp->pcnt; 620 } while (read_seqcount_retry(s, start)); 621 622 ADD_COUNTER(counters[i], bcnt, pcnt); 623 ++i; 624 cond_resched(); 625 } 626 } 627 } 628 629 static void get_old_counters(const struct xt_table_info *t, 630 struct xt_counters counters[]) 631 { 632 struct arpt_entry *iter; 633 unsigned int cpu, i; 634 635 for_each_possible_cpu(cpu) { 636 i = 0; 637 xt_entry_foreach(iter, t->entries, t->size) { 638 struct xt_counters *tmp; 639 640 tmp = xt_get_per_cpu_counter(&iter->counters, cpu); 641 ADD_COUNTER(counters[i], tmp->bcnt, tmp->pcnt); 642 ++i; 643 } 644 cond_resched(); 645 } 646 } 647 648 static struct xt_counters *alloc_counters(const struct xt_table *table) 649 { 650 unsigned int countersize; 651 struct xt_counters *counters; 652 const struct xt_table_info *private = table->private; 653 654 /* We need atomic snapshot of counters: rest doesn't change 655 * (other than comefrom, which userspace doesn't care 656 * about). 657 */ 658 countersize = sizeof(struct xt_counters) * private->number; 659 counters = vzalloc(countersize); 660 661 if (counters == NULL) 662 return ERR_PTR(-ENOMEM); 663 664 get_counters(private, counters); 665 666 return counters; 667 } 668 669 static int copy_entries_to_user(unsigned int total_size, 670 const struct xt_table *table, 671 void __user *userptr) 672 { 673 unsigned int off, num; 674 const struct arpt_entry *e; 675 struct xt_counters *counters; 676 struct xt_table_info *private = table->private; 677 int ret = 0; 678 void *loc_cpu_entry; 679 680 counters = alloc_counters(table); 681 if (IS_ERR(counters)) 682 return PTR_ERR(counters); 683 684 loc_cpu_entry = private->entries; 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 = loc_cpu_entry + off; 692 if (copy_to_user(userptr + off, e, sizeof(*e))) { 693 ret = -EFAULT; 694 goto free_counters; 695 } 696 if (copy_to_user(userptr + off 697 + offsetof(struct arpt_entry, counters), 698 &counters[num], 699 sizeof(counters[num])) != 0) { 700 ret = -EFAULT; 701 goto free_counters; 702 } 703 704 t = arpt_get_target_c(e); 705 if (xt_target_to_user(t, userptr + off + e->target_offset)) { 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 ret = xt_compat_init_offsets(NFPROTO_ARP, info->number); 779 if (ret) 780 return ret; 781 xt_entry_foreach(iter, loc_cpu_entry, info->size) { 782 ret = compat_calc_entry(iter, info, loc_cpu_entry, newinfo); 783 if (ret != 0) 784 return ret; 785 } 786 return 0; 787 } 788 #endif 789 790 static int get_info(struct net *net, void __user *user, 791 const int *len, int compat) 792 { 793 char name[XT_TABLE_MAXNAMELEN]; 794 struct xt_table *t; 795 int ret; 796 797 if (*len != sizeof(struct arpt_getinfo)) 798 return -EINVAL; 799 800 if (copy_from_user(name, user, sizeof(name)) != 0) 801 return -EFAULT; 802 803 name[XT_TABLE_MAXNAMELEN-1] = '\0'; 804 #ifdef CONFIG_COMPAT 805 if (compat) 806 xt_compat_lock(NFPROTO_ARP); 807 #endif 808 t = xt_request_find_table_lock(net, NFPROTO_ARP, name); 809 if (!IS_ERR(t)) { 810 struct arpt_getinfo info; 811 const struct xt_table_info *private = t->private; 812 #ifdef CONFIG_COMPAT 813 struct xt_table_info tmp; 814 815 if (compat) { 816 ret = compat_table_info(private, &tmp); 817 xt_compat_flush_offsets(NFPROTO_ARP); 818 private = &tmp; 819 } 820 #endif 821 memset(&info, 0, sizeof(info)); 822 info.valid_hooks = t->valid_hooks; 823 memcpy(info.hook_entry, private->hook_entry, 824 sizeof(info.hook_entry)); 825 memcpy(info.underflow, private->underflow, 826 sizeof(info.underflow)); 827 info.num_entries = private->number; 828 info.size = private->size; 829 strcpy(info.name, name); 830 831 if (copy_to_user(user, &info, *len) != 0) 832 ret = -EFAULT; 833 else 834 ret = 0; 835 xt_table_unlock(t); 836 module_put(t->me); 837 } else 838 ret = PTR_ERR(t); 839 #ifdef CONFIG_COMPAT 840 if (compat) 841 xt_compat_unlock(NFPROTO_ARP); 842 #endif 843 return ret; 844 } 845 846 static int get_entries(struct net *net, struct arpt_get_entries __user *uptr, 847 const int *len) 848 { 849 int ret; 850 struct arpt_get_entries get; 851 struct xt_table *t; 852 853 if (*len < sizeof(get)) 854 return -EINVAL; 855 if (copy_from_user(&get, uptr, sizeof(get)) != 0) 856 return -EFAULT; 857 if (*len != sizeof(struct arpt_get_entries) + get.size) 858 return -EINVAL; 859 860 get.name[sizeof(get.name) - 1] = '\0'; 861 862 t = xt_find_table_lock(net, NFPROTO_ARP, get.name); 863 if (!IS_ERR(t)) { 864 const struct xt_table_info *private = t->private; 865 866 if (get.size == private->size) 867 ret = copy_entries_to_user(private->size, 868 t, uptr->entrytable); 869 else 870 ret = -EAGAIN; 871 872 module_put(t->me); 873 xt_table_unlock(t); 874 } else 875 ret = PTR_ERR(t); 876 877 return ret; 878 } 879 880 static int __do_replace(struct net *net, const char *name, 881 unsigned int valid_hooks, 882 struct xt_table_info *newinfo, 883 unsigned int num_counters, 884 void __user *counters_ptr) 885 { 886 int ret; 887 struct xt_table *t; 888 struct xt_table_info *oldinfo; 889 struct xt_counters *counters; 890 void *loc_cpu_old_entry; 891 struct arpt_entry *iter; 892 893 ret = 0; 894 counters = xt_counters_alloc(num_counters); 895 if (!counters) { 896 ret = -ENOMEM; 897 goto out; 898 } 899 900 t = xt_request_find_table_lock(net, NFPROTO_ARP, name); 901 if (IS_ERR(t)) { 902 ret = PTR_ERR(t); 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 xt_table_unlock(t); 925 926 get_old_counters(oldinfo, counters); 927 928 /* Decrease module usage counts and free resource */ 929 loc_cpu_old_entry = oldinfo->entries; 930 xt_entry_foreach(iter, loc_cpu_old_entry, oldinfo->size) 931 cleanup_entry(iter, net); 932 933 xt_free_table_info(oldinfo); 934 if (copy_to_user(counters_ptr, counters, 935 sizeof(struct xt_counters) * num_counters) != 0) { 936 /* Silent error, can't fail, new table is already in place */ 937 net_warn_ratelimited("arptables: counters copy to user failed while replacing table\n"); 938 } 939 vfree(counters); 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(net, 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, net); 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 (IS_ERR(t)) { 1018 ret = PTR_ERR(t); 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[]; 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 arpt_entry *de; 1133 unsigned int origsize; 1134 int h; 1135 1136 origsize = *size; 1137 de = *dstptr; 1138 memcpy(de, e, sizeof(struct arpt_entry)); 1139 memcpy(&de->counters, &e->counters, sizeof(e->counters)); 1140 1141 *dstptr += sizeof(struct arpt_entry); 1142 *size += sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry); 1143 1144 de->target_offset = e->target_offset - (origsize - *size); 1145 t = compat_arpt_get_target(e); 1146 xt_compat_target_from_user(t, dstptr, size); 1147 1148 de->next_offset = e->next_offset - (origsize - *size); 1149 for (h = 0; h < NF_ARP_NUMHOOKS; h++) { 1150 if ((unsigned char *)de - base < newinfo->hook_entry[h]) 1151 newinfo->hook_entry[h] -= origsize - *size; 1152 if ((unsigned char *)de - base < newinfo->underflow[h]) 1153 newinfo->underflow[h] -= origsize - *size; 1154 } 1155 } 1156 1157 static int translate_compat_table(struct net *net, 1158 struct xt_table_info **pinfo, 1159 void **pentry0, 1160 const struct compat_arpt_replace *compatr) 1161 { 1162 unsigned int i, j; 1163 struct xt_table_info *newinfo, *info; 1164 void *pos, *entry0, *entry1; 1165 struct compat_arpt_entry *iter0; 1166 struct arpt_replace repl; 1167 unsigned int size; 1168 int ret; 1169 1170 info = *pinfo; 1171 entry0 = *pentry0; 1172 size = compatr->size; 1173 info->number = compatr->num_entries; 1174 1175 j = 0; 1176 xt_compat_lock(NFPROTO_ARP); 1177 ret = xt_compat_init_offsets(NFPROTO_ARP, compatr->num_entries); 1178 if (ret) 1179 goto out_unlock; 1180 /* Walk through entries, checking offsets. */ 1181 xt_entry_foreach(iter0, entry0, compatr->size) { 1182 ret = check_compat_entry_size_and_hooks(iter0, info, &size, 1183 entry0, 1184 entry0 + compatr->size); 1185 if (ret != 0) 1186 goto out_unlock; 1187 ++j; 1188 } 1189 1190 ret = -EINVAL; 1191 if (j != compatr->num_entries) 1192 goto out_unlock; 1193 1194 ret = -ENOMEM; 1195 newinfo = xt_alloc_table_info(size); 1196 if (!newinfo) 1197 goto out_unlock; 1198 1199 newinfo->number = compatr->num_entries; 1200 for (i = 0; i < NF_ARP_NUMHOOKS; i++) { 1201 newinfo->hook_entry[i] = compatr->hook_entry[i]; 1202 newinfo->underflow[i] = compatr->underflow[i]; 1203 } 1204 entry1 = newinfo->entries; 1205 pos = entry1; 1206 size = compatr->size; 1207 xt_entry_foreach(iter0, entry0, compatr->size) 1208 compat_copy_entry_from_user(iter0, &pos, &size, 1209 newinfo, entry1); 1210 1211 /* all module references in entry0 are now gone */ 1212 1213 xt_compat_flush_offsets(NFPROTO_ARP); 1214 xt_compat_unlock(NFPROTO_ARP); 1215 1216 memcpy(&repl, compatr, sizeof(*compatr)); 1217 1218 for (i = 0; i < NF_ARP_NUMHOOKS; i++) { 1219 repl.hook_entry[i] = newinfo->hook_entry[i]; 1220 repl.underflow[i] = newinfo->underflow[i]; 1221 } 1222 1223 repl.num_counters = 0; 1224 repl.counters = NULL; 1225 repl.size = newinfo->size; 1226 ret = translate_table(net, newinfo, entry1, &repl); 1227 if (ret) 1228 goto free_newinfo; 1229 1230 *pinfo = newinfo; 1231 *pentry0 = entry1; 1232 xt_free_table_info(info); 1233 return 0; 1234 1235 free_newinfo: 1236 xt_free_table_info(newinfo); 1237 return ret; 1238 out_unlock: 1239 xt_compat_flush_offsets(NFPROTO_ARP); 1240 xt_compat_unlock(NFPROTO_ARP); 1241 xt_entry_foreach(iter0, entry0, compatr->size) { 1242 if (j-- == 0) 1243 break; 1244 compat_release_entry(iter0); 1245 } 1246 return ret; 1247 } 1248 1249 static int compat_do_replace(struct net *net, void __user *user, 1250 unsigned int len) 1251 { 1252 int ret; 1253 struct compat_arpt_replace tmp; 1254 struct xt_table_info *newinfo; 1255 void *loc_cpu_entry; 1256 struct arpt_entry *iter; 1257 1258 if (copy_from_user(&tmp, user, sizeof(tmp)) != 0) 1259 return -EFAULT; 1260 1261 /* overflow check */ 1262 if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters)) 1263 return -ENOMEM; 1264 if (tmp.num_counters == 0) 1265 return -EINVAL; 1266 1267 tmp.name[sizeof(tmp.name)-1] = 0; 1268 1269 newinfo = xt_alloc_table_info(tmp.size); 1270 if (!newinfo) 1271 return -ENOMEM; 1272 1273 loc_cpu_entry = newinfo->entries; 1274 if (copy_from_user(loc_cpu_entry, user + sizeof(tmp), tmp.size) != 0) { 1275 ret = -EFAULT; 1276 goto free_newinfo; 1277 } 1278 1279 ret = translate_compat_table(net, &newinfo, &loc_cpu_entry, &tmp); 1280 if (ret != 0) 1281 goto free_newinfo; 1282 1283 ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo, 1284 tmp.num_counters, compat_ptr(tmp.counters)); 1285 if (ret) 1286 goto free_newinfo_untrans; 1287 return 0; 1288 1289 free_newinfo_untrans: 1290 xt_entry_foreach(iter, loc_cpu_entry, newinfo->size) 1291 cleanup_entry(iter, net); 1292 free_newinfo: 1293 xt_free_table_info(newinfo); 1294 return ret; 1295 } 1296 1297 static int compat_do_arpt_set_ctl(struct sock *sk, int cmd, void __user *user, 1298 unsigned int len) 1299 { 1300 int ret; 1301 1302 if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN)) 1303 return -EPERM; 1304 1305 switch (cmd) { 1306 case ARPT_SO_SET_REPLACE: 1307 ret = compat_do_replace(sock_net(sk), user, len); 1308 break; 1309 1310 case ARPT_SO_SET_ADD_COUNTERS: 1311 ret = do_add_counters(sock_net(sk), user, len, 1); 1312 break; 1313 1314 default: 1315 ret = -EINVAL; 1316 } 1317 1318 return ret; 1319 } 1320 1321 static int compat_copy_entry_to_user(struct arpt_entry *e, void __user **dstptr, 1322 compat_uint_t *size, 1323 struct xt_counters *counters, 1324 unsigned int i) 1325 { 1326 struct xt_entry_target *t; 1327 struct compat_arpt_entry __user *ce; 1328 u_int16_t target_offset, next_offset; 1329 compat_uint_t origsize; 1330 int ret; 1331 1332 origsize = *size; 1333 ce = *dstptr; 1334 if (copy_to_user(ce, e, sizeof(struct arpt_entry)) != 0 || 1335 copy_to_user(&ce->counters, &counters[i], 1336 sizeof(counters[i])) != 0) 1337 return -EFAULT; 1338 1339 *dstptr += sizeof(struct compat_arpt_entry); 1340 *size -= sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry); 1341 1342 target_offset = e->target_offset - (origsize - *size); 1343 1344 t = arpt_get_target(e); 1345 ret = xt_compat_target_to_user(t, dstptr, size); 1346 if (ret) 1347 return ret; 1348 next_offset = e->next_offset - (origsize - *size); 1349 if (put_user(target_offset, &ce->target_offset) != 0 || 1350 put_user(next_offset, &ce->next_offset) != 0) 1351 return -EFAULT; 1352 return 0; 1353 } 1354 1355 static int compat_copy_entries_to_user(unsigned int total_size, 1356 struct xt_table *table, 1357 void __user *userptr) 1358 { 1359 struct xt_counters *counters; 1360 const struct xt_table_info *private = table->private; 1361 void __user *pos; 1362 unsigned int size; 1363 int ret = 0; 1364 unsigned int i = 0; 1365 struct arpt_entry *iter; 1366 1367 counters = alloc_counters(table); 1368 if (IS_ERR(counters)) 1369 return PTR_ERR(counters); 1370 1371 pos = userptr; 1372 size = total_size; 1373 xt_entry_foreach(iter, private->entries, total_size) { 1374 ret = compat_copy_entry_to_user(iter, &pos, 1375 &size, counters, i++); 1376 if (ret != 0) 1377 break; 1378 } 1379 vfree(counters); 1380 return ret; 1381 } 1382 1383 struct compat_arpt_get_entries { 1384 char name[XT_TABLE_MAXNAMELEN]; 1385 compat_uint_t size; 1386 struct compat_arpt_entry entrytable[]; 1387 }; 1388 1389 static int compat_get_entries(struct net *net, 1390 struct compat_arpt_get_entries __user *uptr, 1391 int *len) 1392 { 1393 int ret; 1394 struct compat_arpt_get_entries get; 1395 struct xt_table *t; 1396 1397 if (*len < sizeof(get)) 1398 return -EINVAL; 1399 if (copy_from_user(&get, uptr, sizeof(get)) != 0) 1400 return -EFAULT; 1401 if (*len != sizeof(struct compat_arpt_get_entries) + get.size) 1402 return -EINVAL; 1403 1404 get.name[sizeof(get.name) - 1] = '\0'; 1405 1406 xt_compat_lock(NFPROTO_ARP); 1407 t = xt_find_table_lock(net, NFPROTO_ARP, get.name); 1408 if (!IS_ERR(t)) { 1409 const struct xt_table_info *private = t->private; 1410 struct xt_table_info info; 1411 1412 ret = compat_table_info(private, &info); 1413 if (!ret && get.size == info.size) { 1414 ret = compat_copy_entries_to_user(private->size, 1415 t, uptr->entrytable); 1416 } else if (!ret) 1417 ret = -EAGAIN; 1418 1419 xt_compat_flush_offsets(NFPROTO_ARP); 1420 module_put(t->me); 1421 xt_table_unlock(t); 1422 } else 1423 ret = PTR_ERR(t); 1424 1425 xt_compat_unlock(NFPROTO_ARP); 1426 return ret; 1427 } 1428 1429 static int do_arpt_get_ctl(struct sock *, int, void __user *, int *); 1430 1431 static int compat_do_arpt_get_ctl(struct sock *sk, int cmd, void __user *user, 1432 int *len) 1433 { 1434 int ret; 1435 1436 if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN)) 1437 return -EPERM; 1438 1439 switch (cmd) { 1440 case ARPT_SO_GET_INFO: 1441 ret = get_info(sock_net(sk), user, len, 1); 1442 break; 1443 case ARPT_SO_GET_ENTRIES: 1444 ret = compat_get_entries(sock_net(sk), user, len); 1445 break; 1446 default: 1447 ret = do_arpt_get_ctl(sk, cmd, user, len); 1448 } 1449 return ret; 1450 } 1451 #endif 1452 1453 static int do_arpt_set_ctl(struct sock *sk, int cmd, void __user *user, unsigned int len) 1454 { 1455 int ret; 1456 1457 if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN)) 1458 return -EPERM; 1459 1460 switch (cmd) { 1461 case ARPT_SO_SET_REPLACE: 1462 ret = do_replace(sock_net(sk), user, len); 1463 break; 1464 1465 case ARPT_SO_SET_ADD_COUNTERS: 1466 ret = do_add_counters(sock_net(sk), user, len, 0); 1467 break; 1468 1469 default: 1470 ret = -EINVAL; 1471 } 1472 1473 return ret; 1474 } 1475 1476 static int do_arpt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len) 1477 { 1478 int ret; 1479 1480 if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN)) 1481 return -EPERM; 1482 1483 switch (cmd) { 1484 case ARPT_SO_GET_INFO: 1485 ret = get_info(sock_net(sk), user, len, 0); 1486 break; 1487 1488 case ARPT_SO_GET_ENTRIES: 1489 ret = get_entries(sock_net(sk), user, len); 1490 break; 1491 1492 case ARPT_SO_GET_REVISION_TARGET: { 1493 struct xt_get_revision rev; 1494 1495 if (*len != sizeof(rev)) { 1496 ret = -EINVAL; 1497 break; 1498 } 1499 if (copy_from_user(&rev, user, sizeof(rev)) != 0) { 1500 ret = -EFAULT; 1501 break; 1502 } 1503 rev.name[sizeof(rev.name)-1] = 0; 1504 1505 try_then_request_module(xt_find_revision(NFPROTO_ARP, rev.name, 1506 rev.revision, 1, &ret), 1507 "arpt_%s", rev.name); 1508 break; 1509 } 1510 1511 default: 1512 ret = -EINVAL; 1513 } 1514 1515 return ret; 1516 } 1517 1518 static void __arpt_unregister_table(struct net *net, struct xt_table *table) 1519 { 1520 struct xt_table_info *private; 1521 void *loc_cpu_entry; 1522 struct module *table_owner = table->me; 1523 struct arpt_entry *iter; 1524 1525 private = xt_unregister_table(table); 1526 1527 /* Decrease module usage counts and free resources */ 1528 loc_cpu_entry = private->entries; 1529 xt_entry_foreach(iter, loc_cpu_entry, private->size) 1530 cleanup_entry(iter, net); 1531 if (private->number > private->initial_entries) 1532 module_put(table_owner); 1533 xt_free_table_info(private); 1534 } 1535 1536 int arpt_register_table(struct net *net, 1537 const struct xt_table *table, 1538 const struct arpt_replace *repl, 1539 const struct nf_hook_ops *ops, 1540 struct xt_table **res) 1541 { 1542 int ret; 1543 struct xt_table_info *newinfo; 1544 struct xt_table_info bootstrap = {0}; 1545 void *loc_cpu_entry; 1546 struct xt_table *new_table; 1547 1548 newinfo = xt_alloc_table_info(repl->size); 1549 if (!newinfo) 1550 return -ENOMEM; 1551 1552 loc_cpu_entry = newinfo->entries; 1553 memcpy(loc_cpu_entry, repl->entries, repl->size); 1554 1555 ret = translate_table(net, newinfo, loc_cpu_entry, repl); 1556 if (ret != 0) 1557 goto out_free; 1558 1559 new_table = xt_register_table(net, table, &bootstrap, newinfo); 1560 if (IS_ERR(new_table)) { 1561 ret = PTR_ERR(new_table); 1562 goto out_free; 1563 } 1564 1565 /* set res now, will see skbs right after nf_register_net_hooks */ 1566 WRITE_ONCE(*res, new_table); 1567 1568 ret = nf_register_net_hooks(net, ops, hweight32(table->valid_hooks)); 1569 if (ret != 0) { 1570 __arpt_unregister_table(net, new_table); 1571 *res = NULL; 1572 } 1573 1574 return ret; 1575 1576 out_free: 1577 xt_free_table_info(newinfo); 1578 return ret; 1579 } 1580 1581 void arpt_unregister_table(struct net *net, struct xt_table *table, 1582 const struct nf_hook_ops *ops) 1583 { 1584 nf_unregister_net_hooks(net, ops, hweight32(table->valid_hooks)); 1585 __arpt_unregister_table(net, table); 1586 } 1587 1588 /* The built-in targets: standard (NULL) and error. */ 1589 static struct xt_target arpt_builtin_tg[] __read_mostly = { 1590 { 1591 .name = XT_STANDARD_TARGET, 1592 .targetsize = sizeof(int), 1593 .family = NFPROTO_ARP, 1594 #ifdef CONFIG_COMPAT 1595 .compatsize = sizeof(compat_int_t), 1596 .compat_from_user = compat_standard_from_user, 1597 .compat_to_user = compat_standard_to_user, 1598 #endif 1599 }, 1600 { 1601 .name = XT_ERROR_TARGET, 1602 .target = arpt_error, 1603 .targetsize = XT_FUNCTION_MAXNAMELEN, 1604 .family = NFPROTO_ARP, 1605 }, 1606 }; 1607 1608 static struct nf_sockopt_ops arpt_sockopts = { 1609 .pf = PF_INET, 1610 .set_optmin = ARPT_BASE_CTL, 1611 .set_optmax = ARPT_SO_SET_MAX+1, 1612 .set = do_arpt_set_ctl, 1613 #ifdef CONFIG_COMPAT 1614 .compat_set = compat_do_arpt_set_ctl, 1615 #endif 1616 .get_optmin = ARPT_BASE_CTL, 1617 .get_optmax = ARPT_SO_GET_MAX+1, 1618 .get = do_arpt_get_ctl, 1619 #ifdef CONFIG_COMPAT 1620 .compat_get = compat_do_arpt_get_ctl, 1621 #endif 1622 .owner = THIS_MODULE, 1623 }; 1624 1625 static int __net_init arp_tables_net_init(struct net *net) 1626 { 1627 return xt_proto_init(net, NFPROTO_ARP); 1628 } 1629 1630 static void __net_exit arp_tables_net_exit(struct net *net) 1631 { 1632 xt_proto_fini(net, NFPROTO_ARP); 1633 } 1634 1635 static struct pernet_operations arp_tables_net_ops = { 1636 .init = arp_tables_net_init, 1637 .exit = arp_tables_net_exit, 1638 }; 1639 1640 static int __init arp_tables_init(void) 1641 { 1642 int ret; 1643 1644 ret = register_pernet_subsys(&arp_tables_net_ops); 1645 if (ret < 0) 1646 goto err1; 1647 1648 /* No one else will be downing sem now, so we won't sleep */ 1649 ret = xt_register_targets(arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg)); 1650 if (ret < 0) 1651 goto err2; 1652 1653 /* Register setsockopt */ 1654 ret = nf_register_sockopt(&arpt_sockopts); 1655 if (ret < 0) 1656 goto err4; 1657 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