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