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 34MODULE_LICENSE("GPL"); 35MODULE_AUTHOR("David S. Miller <davem@redhat.com>"); 36MODULE_DESCRIPTION("arptables core"); 37 38void *arpt_alloc_initial_table(const struct xt_table *info) 39{ 40 return xt_alloc_initial_table(arpt, ARPT); 41} 42EXPORT_SYMBOL_GPL(arpt_alloc_initial_table); 43 44static 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 */ 64static 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. */ 82static 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 145static 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 155static unsigned int 156arpt_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 164static inline const struct xt_entry_target * 165arpt_get_target_c(const struct arpt_entry *e) 166{ 167 return arpt_get_target((struct arpt_entry *)e); 168} 169 170static inline struct arpt_entry * 171get_entry(const void *base, unsigned int offset) 172{ 173 return (struct arpt_entry *)(base + offset); 174} 175 176static inline 177struct arpt_entry *arpt_next_entry(const struct arpt_entry *entry) 178{ 179 return (void *)entry + entry->next_offset; 180} 181 182unsigned int arpt_do_table(void *priv, 183 struct sk_buff *skb, 184 const struct nf_hook_state *state) 185{ 186 const struct xt_table *table = priv; 187 unsigned int hook = state->hook; 188 static const char nulldevname[IFNAMSIZ] __attribute__((aligned(sizeof(long)))); 189 unsigned int verdict = NF_DROP; 190 const struct arphdr *arp; 191 struct arpt_entry *e, **jumpstack; 192 const char *indev, *outdev; 193 const void *table_base; 194 unsigned int cpu, stackidx = 0; 195 const struct xt_table_info *private; 196 struct xt_action_param acpar; 197 unsigned int addend; 198 199 if (!pskb_may_pull(skb, arp_hdr_len(skb->dev))) 200 return NF_DROP; 201 202 indev = state->in ? state->in->name : nulldevname; 203 outdev = state->out ? state->out->name : nulldevname; 204 205 local_bh_disable(); 206 addend = xt_write_recseq_begin(); 207 private = READ_ONCE(table->private); /* Address dependency. */ 208 cpu = smp_processor_id(); 209 table_base = private->entries; 210 jumpstack = (struct arpt_entry **)private->jumpstack[cpu]; 211 212 /* No TEE support for arptables, so no need to switch to alternate 213 * stack. All targets that reenter must return absolute verdicts. 214 */ 215 e = get_entry(table_base, private->hook_entry[hook]); 216 217 acpar.state = state; 218 acpar.hotdrop = false; 219 220 arp = arp_hdr(skb); 221 do { 222 const struct xt_entry_target *t; 223 struct xt_counters *counter; 224 225 if (!arp_packet_match(arp, skb->dev, indev, outdev, &e->arp)) { 226 e = arpt_next_entry(e); 227 continue; 228 } 229 230 counter = xt_get_this_cpu_counter(&e->counters); 231 ADD_COUNTER(*counter, arp_hdr_len(skb->dev), 1); 232 233 t = arpt_get_target_c(e); 234 235 /* Standard target? */ 236 if (!t->u.kernel.target->target) { 237 int v; 238 239 v = ((struct xt_standard_target *)t)->verdict; 240 if (v < 0) { 241 /* Pop from stack? */ 242 if (v != XT_RETURN) { 243 verdict = (unsigned int)(-v) - 1; 244 break; 245 } 246 if (stackidx == 0) { 247 e = get_entry(table_base, 248 private->underflow[hook]); 249 } else { 250 e = jumpstack[--stackidx]; 251 e = arpt_next_entry(e); 252 } 253 continue; 254 } 255 if (table_base + v 256 != arpt_next_entry(e)) { 257 if (unlikely(stackidx >= private->stacksize)) { 258 verdict = NF_DROP; 259 break; 260 } 261 jumpstack[stackidx++] = e; 262 } 263 264 e = get_entry(table_base, v); 265 continue; 266 } 267 268 acpar.target = t->u.kernel.target; 269 acpar.targinfo = t->data; 270 verdict = t->u.kernel.target->target(skb, &acpar); 271 272 if (verdict == XT_CONTINUE) { 273 /* Target might have changed stuff. */ 274 arp = arp_hdr(skb); 275 e = arpt_next_entry(e); 276 } else { 277 /* Verdict */ 278 break; 279 } 280 } while (!acpar.hotdrop); 281 xt_write_recseq_end(addend); 282 local_bh_enable(); 283 284 if (acpar.hotdrop) 285 return NF_DROP; 286 else 287 return verdict; 288} 289 290/* All zeroes == unconditional rule. */ 291static inline bool unconditional(const struct arpt_entry *e) 292{ 293 static const struct arpt_arp uncond; 294 295 return e->target_offset == sizeof(struct arpt_entry) && 296 memcmp(&e->arp, &uncond, sizeof(uncond)) == 0; 297} 298 299/* Figures out from what hook each rule can be called: returns 0 if 300 * there are loops. Puts hook bitmask in comefrom. 301 */ 302static int mark_source_chains(const struct xt_table_info *newinfo, 303 unsigned int valid_hooks, void *entry0, 304 unsigned int *offsets) 305{ 306 unsigned int hook; 307 308 /* No recursion; use packet counter to save back ptrs (reset 309 * to 0 as we leave), and comefrom to save source hook bitmask. 310 */ 311 for (hook = 0; hook < NF_ARP_NUMHOOKS; hook++) { 312 unsigned int pos = newinfo->hook_entry[hook]; 313 struct arpt_entry *e = 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 /* Return: backtrack through the last 340 * big jump. 341 */ 342 do { 343 e->comefrom ^= (1<<NF_ARP_NUMHOOKS); 344 oldpos = pos; 345 pos = e->counters.pcnt; 346 e->counters.pcnt = 0; 347 348 /* We're at the start. */ 349 if (pos == oldpos) 350 goto next; 351 352 e = entry0 + pos; 353 } while (oldpos == pos + e->next_offset); 354 355 /* Move along one */ 356 size = e->next_offset; 357 e = entry0 + pos + size; 358 if (pos + size >= newinfo->size) 359 return 0; 360 e->counters.pcnt = pos; 361 pos += size; 362 } else { 363 int newpos = t->verdict; 364 365 if (strcmp(t->target.u.user.name, 366 XT_STANDARD_TARGET) == 0 && 367 newpos >= 0) { 368 /* This a jump; chase it. */ 369 if (!xt_find_jump_offset(offsets, newpos, 370 newinfo->number)) 371 return 0; 372 } else { 373 /* ... this is a fallthru */ 374 newpos = pos + e->next_offset; 375 if (newpos >= newinfo->size) 376 return 0; 377 } 378 e = entry0 + newpos; 379 e->counters.pcnt = pos; 380 pos = newpos; 381 } 382 } 383next: ; 384 } 385 return 1; 386} 387 388static int check_target(struct arpt_entry *e, struct net *net, const char *name) 389{ 390 struct xt_entry_target *t = arpt_get_target(e); 391 struct xt_tgchk_param par = { 392 .net = net, 393 .table = name, 394 .entryinfo = e, 395 .target = t->u.kernel.target, 396 .targinfo = t->data, 397 .hook_mask = e->comefrom, 398 .family = NFPROTO_ARP, 399 }; 400 401 return xt_check_target(&par, t->u.target_size - sizeof(*t), 0, false); 402} 403 404static int 405find_check_entry(struct arpt_entry *e, struct net *net, const char *name, 406 unsigned int size, 407 struct xt_percpu_counter_alloc_state *alloc_state) 408{ 409 struct xt_entry_target *t; 410 struct xt_target *target; 411 int ret; 412 413 if (!xt_percpu_counter_alloc(alloc_state, &e->counters)) 414 return -ENOMEM; 415 416 t = arpt_get_target(e); 417 target = xt_request_find_target(NFPROTO_ARP, t->u.user.name, 418 t->u.user.revision); 419 if (IS_ERR(target)) { 420 ret = PTR_ERR(target); 421 goto out; 422 } 423 t->u.kernel.target = target; 424 425 ret = check_target(e, net, name); 426 if (ret) 427 goto err; 428 return 0; 429err: 430 module_put(t->u.kernel.target->me); 431out: 432 xt_percpu_counter_free(&e->counters); 433 434 return ret; 435} 436 437static bool check_underflow(const struct arpt_entry *e) 438{ 439 const struct xt_entry_target *t; 440 unsigned int verdict; 441 442 if (!unconditional(e)) 443 return false; 444 t = arpt_get_target_c(e); 445 if (strcmp(t->u.user.name, XT_STANDARD_TARGET) != 0) 446 return false; 447 verdict = ((struct xt_standard_target *)t)->verdict; 448 verdict = -verdict - 1; 449 return verdict == NF_DROP || verdict == NF_ACCEPT; 450} 451 452static inline int check_entry_size_and_hooks(struct arpt_entry *e, 453 struct xt_table_info *newinfo, 454 const unsigned char *base, 455 const unsigned char *limit, 456 const unsigned int *hook_entries, 457 const unsigned int *underflows, 458 unsigned int valid_hooks) 459{ 460 unsigned int h; 461 int err; 462 463 if ((unsigned long)e % __alignof__(struct arpt_entry) != 0 || 464 (unsigned char *)e + sizeof(struct arpt_entry) >= limit || 465 (unsigned char *)e + e->next_offset > limit) 466 return -EINVAL; 467 468 if (e->next_offset 469 < sizeof(struct arpt_entry) + sizeof(struct xt_entry_target)) 470 return -EINVAL; 471 472 if (!arp_checkentry(&e->arp)) 473 return -EINVAL; 474 475 err = xt_check_entry_offsets(e, e->elems, e->target_offset, 476 e->next_offset); 477 if (err) 478 return err; 479 480 /* Check hooks & underflows */ 481 for (h = 0; h < NF_ARP_NUMHOOKS; h++) { 482 if (!(valid_hooks & (1 << h))) 483 continue; 484 if ((unsigned char *)e - base == hook_entries[h]) 485 newinfo->hook_entry[h] = hook_entries[h]; 486 if ((unsigned char *)e - base == underflows[h]) { 487 if (!check_underflow(e)) 488 return -EINVAL; 489 490 newinfo->underflow[h] = underflows[h]; 491 } 492 } 493 494 /* Clear counters and comefrom */ 495 e->counters = ((struct xt_counters) { 0, 0 }); 496 e->comefrom = 0; 497 return 0; 498} 499 500static void cleanup_entry(struct arpt_entry *e, struct net *net) 501{ 502 struct xt_tgdtor_param par; 503 struct xt_entry_target *t; 504 505 t = arpt_get_target(e); 506 par.net = net; 507 par.target = t->u.kernel.target; 508 par.targinfo = t->data; 509 par.family = NFPROTO_ARP; 510 if (par.target->destroy != NULL) 511 par.target->destroy(&par); 512 module_put(par.target->me); 513 xt_percpu_counter_free(&e->counters); 514} 515 516/* Checks and translates the user-supplied table segment (held in 517 * newinfo). 518 */ 519static int translate_table(struct net *net, 520 struct xt_table_info *newinfo, 521 void *entry0, 522 const struct arpt_replace *repl) 523{ 524 struct xt_percpu_counter_alloc_state alloc_state = { 0 }; 525 struct arpt_entry *iter; 526 unsigned int *offsets; 527 unsigned int i; 528 int ret = 0; 529 530 newinfo->size = repl->size; 531 newinfo->number = repl->num_entries; 532 533 /* Init all hooks to impossible value. */ 534 for (i = 0; i < NF_ARP_NUMHOOKS; i++) { 535 newinfo->hook_entry[i] = 0xFFFFFFFF; 536 newinfo->underflow[i] = 0xFFFFFFFF; 537 } 538 539 offsets = xt_alloc_entry_offsets(newinfo->number); 540 if (!offsets) 541 return -ENOMEM; 542 i = 0; 543 544 /* Walk through entries, checking offsets. */ 545 xt_entry_foreach(iter, entry0, newinfo->size) { 546 ret = check_entry_size_and_hooks(iter, newinfo, entry0, 547 entry0 + repl->size, 548 repl->hook_entry, 549 repl->underflow, 550 repl->valid_hooks); 551 if (ret != 0) 552 goto out_free; 553 if (i < repl->num_entries) 554 offsets[i] = (void *)iter - entry0; 555 ++i; 556 if (strcmp(arpt_get_target(iter)->u.user.name, 557 XT_ERROR_TARGET) == 0) 558 ++newinfo->stacksize; 559 } 560 561 ret = -EINVAL; 562 if (i != repl->num_entries) 563 goto out_free; 564 565 ret = xt_check_table_hooks(newinfo, repl->valid_hooks); 566 if (ret) 567 goto out_free; 568 569 if (!mark_source_chains(newinfo, repl->valid_hooks, entry0, offsets)) { 570 ret = -ELOOP; 571 goto out_free; 572 } 573 kvfree(offsets); 574 575 /* Finally, each sanity check must pass */ 576 i = 0; 577 xt_entry_foreach(iter, entry0, newinfo->size) { 578 ret = find_check_entry(iter, net, repl->name, repl->size, 579 &alloc_state); 580 if (ret != 0) 581 break; 582 ++i; 583 } 584 585 if (ret != 0) { 586 xt_entry_foreach(iter, entry0, newinfo->size) { 587 if (i-- == 0) 588 break; 589 cleanup_entry(iter, net); 590 } 591 return ret; 592 } 593 594 return ret; 595 out_free: 596 kvfree(offsets); 597 return ret; 598} 599 600static void get_counters(const struct xt_table_info *t, 601 struct xt_counters counters[]) 602{ 603 struct arpt_entry *iter; 604 unsigned int cpu; 605 unsigned int i; 606 607 for_each_possible_cpu(cpu) { 608 seqcount_t *s = &per_cpu(xt_recseq, cpu); 609 610 i = 0; 611 xt_entry_foreach(iter, t->entries, t->size) { 612 struct xt_counters *tmp; 613 u64 bcnt, pcnt; 614 unsigned int start; 615 616 tmp = xt_get_per_cpu_counter(&iter->counters, cpu); 617 do { 618 start = read_seqcount_begin(s); 619 bcnt = tmp->bcnt; 620 pcnt = tmp->pcnt; 621 } while (read_seqcount_retry(s, start)); 622 623 ADD_COUNTER(counters[i], bcnt, pcnt); 624 ++i; 625 cond_resched(); 626 } 627 } 628} 629 630static void get_old_counters(const struct xt_table_info *t, 631 struct xt_counters counters[]) 632{ 633 struct arpt_entry *iter; 634 unsigned int cpu, i; 635 636 for_each_possible_cpu(cpu) { 637 i = 0; 638 xt_entry_foreach(iter, t->entries, t->size) { 639 struct xt_counters *tmp; 640 641 tmp = xt_get_per_cpu_counter(&iter->counters, cpu); 642 ADD_COUNTER(counters[i], tmp->bcnt, tmp->pcnt); 643 ++i; 644 } 645 cond_resched(); 646 } 647} 648 649static struct xt_counters *alloc_counters(const struct xt_table *table) 650{ 651 unsigned int countersize; 652 struct xt_counters *counters; 653 const struct xt_table_info *private = table->private; 654 655 /* We need atomic snapshot of counters: rest doesn't change 656 * (other than comefrom, which userspace doesn't care 657 * about). 658 */ 659 countersize = sizeof(struct xt_counters) * private->number; 660 counters = vzalloc(countersize); 661 662 if (counters == NULL) 663 return ERR_PTR(-ENOMEM); 664 665 get_counters(private, counters); 666 667 return counters; 668} 669 670static int copy_entries_to_user(unsigned int total_size, 671 const struct xt_table *table, 672 void __user *userptr) 673{ 674 unsigned int off, num; 675 const struct arpt_entry *e; 676 struct xt_counters *counters; 677 struct xt_table_info *private = table->private; 678 int ret = 0; 679 void *loc_cpu_entry; 680 681 counters = alloc_counters(table); 682 if (IS_ERR(counters)) 683 return PTR_ERR(counters); 684 685 loc_cpu_entry = private->entries; 686 687 /* FIXME: use iterator macros --RR */ 688 /* ... then go back and fix counters and names */ 689 for (off = 0, num = 0; off < total_size; off += e->next_offset, num++){ 690 const struct xt_entry_target *t; 691 692 e = loc_cpu_entry + off; 693 if (copy_to_user(userptr + off, e, sizeof(*e))) { 694 ret = -EFAULT; 695 goto free_counters; 696 } 697 if (copy_to_user(userptr + off 698 + offsetof(struct arpt_entry, counters), 699 &counters[num], 700 sizeof(counters[num])) != 0) { 701 ret = -EFAULT; 702 goto free_counters; 703 } 704 705 t = arpt_get_target_c(e); 706 if (xt_target_to_user(t, userptr + off + e->target_offset)) { 707 ret = -EFAULT; 708 goto free_counters; 709 } 710 } 711 712 free_counters: 713 vfree(counters); 714 return ret; 715} 716 717#ifdef CONFIG_NETFILTER_XTABLES_COMPAT 718static void compat_standard_from_user(void *dst, const void *src) 719{ 720 int v = *(compat_int_t *)src; 721 722 if (v > 0) 723 v += xt_compat_calc_jump(NFPROTO_ARP, v); 724 memcpy(dst, &v, sizeof(v)); 725} 726 727static int compat_standard_to_user(void __user *dst, const void *src) 728{ 729 compat_int_t cv = *(int *)src; 730 731 if (cv > 0) 732 cv -= xt_compat_calc_jump(NFPROTO_ARP, cv); 733 return copy_to_user(dst, &cv, sizeof(cv)) ? -EFAULT : 0; 734} 735 736static int compat_calc_entry(const struct arpt_entry *e, 737 const struct xt_table_info *info, 738 const void *base, struct xt_table_info *newinfo) 739{ 740 const struct xt_entry_target *t; 741 unsigned int entry_offset; 742 int off, i, ret; 743 744 off = sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry); 745 entry_offset = (void *)e - base; 746 747 t = arpt_get_target_c(e); 748 off += xt_compat_target_offset(t->u.kernel.target); 749 newinfo->size -= off; 750 ret = xt_compat_add_offset(NFPROTO_ARP, entry_offset, off); 751 if (ret) 752 return ret; 753 754 for (i = 0; i < NF_ARP_NUMHOOKS; i++) { 755 if (info->hook_entry[i] && 756 (e < (struct arpt_entry *)(base + info->hook_entry[i]))) 757 newinfo->hook_entry[i] -= off; 758 if (info->underflow[i] && 759 (e < (struct arpt_entry *)(base + info->underflow[i]))) 760 newinfo->underflow[i] -= off; 761 } 762 return 0; 763} 764 765static int compat_table_info(const struct xt_table_info *info, 766 struct xt_table_info *newinfo) 767{ 768 struct arpt_entry *iter; 769 const void *loc_cpu_entry; 770 int ret; 771 772 if (!newinfo || !info) 773 return -EINVAL; 774 775 /* we dont care about newinfo->entries */ 776 memcpy(newinfo, info, offsetof(struct xt_table_info, entries)); 777 newinfo->initial_entries = 0; 778 loc_cpu_entry = info->entries; 779 ret = xt_compat_init_offsets(NFPROTO_ARP, info->number); 780 if (ret) 781 return ret; 782 xt_entry_foreach(iter, loc_cpu_entry, info->size) { 783 ret = compat_calc_entry(iter, info, loc_cpu_entry, newinfo); 784 if (ret != 0) 785 return ret; 786 } 787 return 0; 788} 789#endif 790 791static int get_info(struct net *net, void __user *user, const int *len) 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_NETFILTER_XTABLES_COMPAT 805 if (in_compat_syscall()) 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_NETFILTER_XTABLES_COMPAT 813 struct xt_table_info tmp; 814 815 if (in_compat_syscall()) { 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_NETFILTER_XTABLES_COMPAT 840 if (in_compat_syscall()) 841 xt_compat_unlock(NFPROTO_ARP); 842#endif 843 return ret; 844} 845 846static 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 880static 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 951static int do_replace(struct net *net, sockptr_t arg, unsigned int len) 952{ 953 int ret; 954 struct arpt_replace tmp; 955 struct xt_table_info *newinfo; 956 void *loc_cpu_entry; 957 struct arpt_entry *iter; 958 959 if (len < sizeof(tmp)) 960 return -EINVAL; 961 if (copy_from_sockptr(&tmp, arg, sizeof(tmp)) != 0) 962 return -EFAULT; 963 964 /* overflow check */ 965 if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters)) 966 return -ENOMEM; 967 if (tmp.num_counters == 0) 968 return -EINVAL; 969 if ((u64)len < (u64)tmp.size + sizeof(tmp)) 970 return -EINVAL; 971 972 tmp.name[sizeof(tmp.name)-1] = 0; 973 974 newinfo = xt_alloc_table_info(tmp.size); 975 if (!newinfo) 976 return -ENOMEM; 977 978 loc_cpu_entry = newinfo->entries; 979 if (copy_from_sockptr_offset(loc_cpu_entry, arg, sizeof(tmp), 980 tmp.size) != 0) { 981 ret = -EFAULT; 982 goto free_newinfo; 983 } 984 985 ret = translate_table(net, newinfo, loc_cpu_entry, &tmp); 986 if (ret != 0) 987 goto free_newinfo; 988 989 ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo, 990 tmp.num_counters, tmp.counters); 991 if (ret) 992 goto free_newinfo_untrans; 993 return 0; 994 995 free_newinfo_untrans: 996 xt_entry_foreach(iter, loc_cpu_entry, newinfo->size) 997 cleanup_entry(iter, net); 998 free_newinfo: 999 xt_free_table_info(newinfo); 1000 return ret; 1001} 1002 1003static int do_add_counters(struct net *net, sockptr_t arg, unsigned int len) 1004{ 1005 unsigned int i; 1006 struct xt_counters_info tmp; 1007 struct xt_counters *paddc; 1008 struct xt_table *t; 1009 const struct xt_table_info *private; 1010 int ret = 0; 1011 struct arpt_entry *iter; 1012 unsigned int addend; 1013 1014 paddc = xt_copy_counters(arg, len, &tmp); 1015 if (IS_ERR(paddc)) 1016 return PTR_ERR(paddc); 1017 1018 t = xt_find_table_lock(net, NFPROTO_ARP, tmp.name); 1019 if (IS_ERR(t)) { 1020 ret = PTR_ERR(t); 1021 goto free; 1022 } 1023 1024 local_bh_disable(); 1025 private = t->private; 1026 if (private->number != tmp.num_counters) { 1027 ret = -EINVAL; 1028 goto unlock_up_free; 1029 } 1030 1031 i = 0; 1032 1033 addend = xt_write_recseq_begin(); 1034 xt_entry_foreach(iter, private->entries, private->size) { 1035 struct xt_counters *tmp; 1036 1037 tmp = xt_get_this_cpu_counter(&iter->counters); 1038 ADD_COUNTER(*tmp, paddc[i].bcnt, paddc[i].pcnt); 1039 ++i; 1040 } 1041 xt_write_recseq_end(addend); 1042 unlock_up_free: 1043 local_bh_enable(); 1044 xt_table_unlock(t); 1045 module_put(t->me); 1046 free: 1047 vfree(paddc); 1048 1049 return ret; 1050} 1051 1052#ifdef CONFIG_NETFILTER_XTABLES_COMPAT 1053struct compat_arpt_replace { 1054 char name[XT_TABLE_MAXNAMELEN]; 1055 u32 valid_hooks; 1056 u32 num_entries; 1057 u32 size; 1058 u32 hook_entry[NF_ARP_NUMHOOKS]; 1059 u32 underflow[NF_ARP_NUMHOOKS]; 1060 u32 num_counters; 1061 compat_uptr_t counters; 1062 struct compat_arpt_entry entries[]; 1063}; 1064 1065static inline void compat_release_entry(struct compat_arpt_entry *e) 1066{ 1067 struct xt_entry_target *t; 1068 1069 t = compat_arpt_get_target(e); 1070 module_put(t->u.kernel.target->me); 1071} 1072 1073static int 1074check_compat_entry_size_and_hooks(struct compat_arpt_entry *e, 1075 struct xt_table_info *newinfo, 1076 unsigned int *size, 1077 const unsigned char *base, 1078 const unsigned char *limit) 1079{ 1080 struct xt_entry_target *t; 1081 struct xt_target *target; 1082 unsigned int entry_offset; 1083 int ret, off; 1084 1085 if ((unsigned long)e % __alignof__(struct compat_arpt_entry) != 0 || 1086 (unsigned char *)e + sizeof(struct compat_arpt_entry) >= limit || 1087 (unsigned char *)e + e->next_offset > limit) 1088 return -EINVAL; 1089 1090 if (e->next_offset < sizeof(struct compat_arpt_entry) + 1091 sizeof(struct compat_xt_entry_target)) 1092 return -EINVAL; 1093 1094 if (!arp_checkentry(&e->arp)) 1095 return -EINVAL; 1096 1097 ret = xt_compat_check_entry_offsets(e, e->elems, e->target_offset, 1098 e->next_offset); 1099 if (ret) 1100 return ret; 1101 1102 off = sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry); 1103 entry_offset = (void *)e - (void *)base; 1104 1105 t = compat_arpt_get_target(e); 1106 target = xt_request_find_target(NFPROTO_ARP, t->u.user.name, 1107 t->u.user.revision); 1108 if (IS_ERR(target)) { 1109 ret = PTR_ERR(target); 1110 goto out; 1111 } 1112 t->u.kernel.target = target; 1113 1114 off += xt_compat_target_offset(target); 1115 *size += off; 1116 ret = xt_compat_add_offset(NFPROTO_ARP, entry_offset, off); 1117 if (ret) 1118 goto release_target; 1119 1120 return 0; 1121 1122release_target: 1123 module_put(t->u.kernel.target->me); 1124out: 1125 return ret; 1126} 1127 1128static void 1129compat_copy_entry_from_user(struct compat_arpt_entry *e, void **dstptr, 1130 unsigned int *size, 1131 struct xt_table_info *newinfo, unsigned char *base) 1132{ 1133 struct xt_entry_target *t; 1134 struct arpt_entry *de; 1135 unsigned int origsize; 1136 int h; 1137 1138 origsize = *size; 1139 de = *dstptr; 1140 memcpy(de, e, sizeof(struct arpt_entry)); 1141 memcpy(&de->counters, &e->counters, sizeof(e->counters)); 1142 1143 *dstptr += sizeof(struct arpt_entry); 1144 *size += sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry); 1145 1146 de->target_offset = e->target_offset - (origsize - *size); 1147 t = compat_arpt_get_target(e); 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 1159static int translate_compat_table(struct net *net, 1160 struct xt_table_info **pinfo, 1161 void **pentry0, 1162 const struct compat_arpt_replace *compatr) 1163{ 1164 unsigned int i, j; 1165 struct xt_table_info *newinfo, *info; 1166 void *pos, *entry0, *entry1; 1167 struct compat_arpt_entry *iter0; 1168 struct arpt_replace repl; 1169 unsigned int size; 1170 int ret; 1171 1172 info = *pinfo; 1173 entry0 = *pentry0; 1174 size = compatr->size; 1175 info->number = compatr->num_entries; 1176 1177 j = 0; 1178 xt_compat_lock(NFPROTO_ARP); 1179 ret = xt_compat_init_offsets(NFPROTO_ARP, compatr->num_entries); 1180 if (ret) 1181 goto out_unlock; 1182 /* Walk through entries, checking offsets. */ 1183 xt_entry_foreach(iter0, entry0, compatr->size) { 1184 ret = check_compat_entry_size_and_hooks(iter0, info, &size, 1185 entry0, 1186 entry0 + compatr->size); 1187 if (ret != 0) 1188 goto out_unlock; 1189 ++j; 1190 } 1191 1192 ret = -EINVAL; 1193 if (j != compatr->num_entries) 1194 goto out_unlock; 1195 1196 ret = -ENOMEM; 1197 newinfo = xt_alloc_table_info(size); 1198 if (!newinfo) 1199 goto out_unlock; 1200 1201 memset(newinfo->entries, 0, size); 1202 1203 newinfo->number = compatr->num_entries; 1204 for (i = 0; i < NF_ARP_NUMHOOKS; i++) { 1205 newinfo->hook_entry[i] = compatr->hook_entry[i]; 1206 newinfo->underflow[i] = compatr->underflow[i]; 1207 } 1208 entry1 = newinfo->entries; 1209 pos = entry1; 1210 size = compatr->size; 1211 xt_entry_foreach(iter0, entry0, compatr->size) 1212 compat_copy_entry_from_user(iter0, &pos, &size, 1213 newinfo, entry1); 1214 1215 /* all module references in entry0 are now gone */ 1216 1217 xt_compat_flush_offsets(NFPROTO_ARP); 1218 xt_compat_unlock(NFPROTO_ARP); 1219 1220 memcpy(&repl, compatr, sizeof(*compatr)); 1221 1222 for (i = 0; i < NF_ARP_NUMHOOKS; i++) { 1223 repl.hook_entry[i] = newinfo->hook_entry[i]; 1224 repl.underflow[i] = newinfo->underflow[i]; 1225 } 1226 1227 repl.num_counters = 0; 1228 repl.counters = NULL; 1229 repl.size = newinfo->size; 1230 ret = translate_table(net, newinfo, entry1, &repl); 1231 if (ret) 1232 goto free_newinfo; 1233 1234 *pinfo = newinfo; 1235 *pentry0 = entry1; 1236 xt_free_table_info(info); 1237 return 0; 1238 1239free_newinfo: 1240 xt_free_table_info(newinfo); 1241 return ret; 1242out_unlock: 1243 xt_compat_flush_offsets(NFPROTO_ARP); 1244 xt_compat_unlock(NFPROTO_ARP); 1245 xt_entry_foreach(iter0, entry0, compatr->size) { 1246 if (j-- == 0) 1247 break; 1248 compat_release_entry(iter0); 1249 } 1250 return ret; 1251} 1252 1253static int compat_do_replace(struct net *net, sockptr_t arg, unsigned int len) 1254{ 1255 int ret; 1256 struct compat_arpt_replace tmp; 1257 struct xt_table_info *newinfo; 1258 void *loc_cpu_entry; 1259 struct arpt_entry *iter; 1260 1261 if (len < sizeof(tmp)) 1262 return -EINVAL; 1263 if (copy_from_sockptr(&tmp, arg, sizeof(tmp)) != 0) 1264 return -EFAULT; 1265 1266 /* overflow check */ 1267 if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters)) 1268 return -ENOMEM; 1269 if (tmp.num_counters == 0) 1270 return -EINVAL; 1271 if ((u64)len < (u64)tmp.size + sizeof(tmp)) 1272 return -EINVAL; 1273 1274 tmp.name[sizeof(tmp.name)-1] = 0; 1275 1276 newinfo = xt_alloc_table_info(tmp.size); 1277 if (!newinfo) 1278 return -ENOMEM; 1279 1280 loc_cpu_entry = newinfo->entries; 1281 if (copy_from_sockptr_offset(loc_cpu_entry, arg, sizeof(tmp), 1282 tmp.size) != 0) { 1283 ret = -EFAULT; 1284 goto free_newinfo; 1285 } 1286 1287 ret = translate_compat_table(net, &newinfo, &loc_cpu_entry, &tmp); 1288 if (ret != 0) 1289 goto free_newinfo; 1290 1291 ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo, 1292 tmp.num_counters, compat_ptr(tmp.counters)); 1293 if (ret) 1294 goto free_newinfo_untrans; 1295 return 0; 1296 1297 free_newinfo_untrans: 1298 xt_entry_foreach(iter, loc_cpu_entry, newinfo->size) 1299 cleanup_entry(iter, net); 1300 free_newinfo: 1301 xt_free_table_info(newinfo); 1302 return ret; 1303} 1304 1305static int compat_copy_entry_to_user(struct arpt_entry *e, void __user **dstptr, 1306 compat_uint_t *size, 1307 struct xt_counters *counters, 1308 unsigned int i) 1309{ 1310 struct xt_entry_target *t; 1311 struct compat_arpt_entry __user *ce; 1312 u_int16_t target_offset, next_offset; 1313 compat_uint_t origsize; 1314 int ret; 1315 1316 origsize = *size; 1317 ce = *dstptr; 1318 if (copy_to_user(ce, e, sizeof(struct arpt_entry)) != 0 || 1319 copy_to_user(&ce->counters, &counters[i], 1320 sizeof(counters[i])) != 0) 1321 return -EFAULT; 1322 1323 *dstptr += sizeof(struct compat_arpt_entry); 1324 *size -= sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry); 1325 1326 target_offset = e->target_offset - (origsize - *size); 1327 1328 t = arpt_get_target(e); 1329 ret = xt_compat_target_to_user(t, dstptr, size); 1330 if (ret) 1331 return ret; 1332 next_offset = e->next_offset - (origsize - *size); 1333 if (put_user(target_offset, &ce->target_offset) != 0 || 1334 put_user(next_offset, &ce->next_offset) != 0) 1335 return -EFAULT; 1336 return 0; 1337} 1338 1339static int compat_copy_entries_to_user(unsigned int total_size, 1340 struct xt_table *table, 1341 void __user *userptr) 1342{ 1343 struct xt_counters *counters; 1344 const struct xt_table_info *private = table->private; 1345 void __user *pos; 1346 unsigned int size; 1347 int ret = 0; 1348 unsigned int i = 0; 1349 struct arpt_entry *iter; 1350 1351 counters = alloc_counters(table); 1352 if (IS_ERR(counters)) 1353 return PTR_ERR(counters); 1354 1355 pos = userptr; 1356 size = total_size; 1357 xt_entry_foreach(iter, private->entries, total_size) { 1358 ret = compat_copy_entry_to_user(iter, &pos, 1359 &size, counters, i++); 1360 if (ret != 0) 1361 break; 1362 } 1363 vfree(counters); 1364 return ret; 1365} 1366 1367struct compat_arpt_get_entries { 1368 char name[XT_TABLE_MAXNAMELEN]; 1369 compat_uint_t size; 1370 struct compat_arpt_entry entrytable[]; 1371}; 1372 1373static int compat_get_entries(struct net *net, 1374 struct compat_arpt_get_entries __user *uptr, 1375 int *len) 1376{ 1377 int ret; 1378 struct compat_arpt_get_entries get; 1379 struct xt_table *t; 1380 1381 if (*len < sizeof(get)) 1382 return -EINVAL; 1383 if (copy_from_user(&get, uptr, sizeof(get)) != 0) 1384 return -EFAULT; 1385 if (*len != sizeof(struct compat_arpt_get_entries) + get.size) 1386 return -EINVAL; 1387 1388 get.name[sizeof(get.name) - 1] = '\0'; 1389 1390 xt_compat_lock(NFPROTO_ARP); 1391 t = xt_find_table_lock(net, NFPROTO_ARP, get.name); 1392 if (!IS_ERR(t)) { 1393 const struct xt_table_info *private = t->private; 1394 struct xt_table_info info; 1395 1396 ret = compat_table_info(private, &info); 1397 if (!ret && get.size == info.size) { 1398 ret = compat_copy_entries_to_user(private->size, 1399 t, uptr->entrytable); 1400 } else if (!ret) 1401 ret = -EAGAIN; 1402 1403 xt_compat_flush_offsets(NFPROTO_ARP); 1404 module_put(t->me); 1405 xt_table_unlock(t); 1406 } else 1407 ret = PTR_ERR(t); 1408 1409 xt_compat_unlock(NFPROTO_ARP); 1410 return ret; 1411} 1412#endif 1413 1414static int do_arpt_set_ctl(struct sock *sk, int cmd, sockptr_t arg, 1415 unsigned int len) 1416{ 1417 int ret; 1418 1419 if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN)) 1420 return -EPERM; 1421 1422 switch (cmd) { 1423 case ARPT_SO_SET_REPLACE: 1424#ifdef CONFIG_NETFILTER_XTABLES_COMPAT 1425 if (in_compat_syscall()) 1426 ret = compat_do_replace(sock_net(sk), arg, len); 1427 else 1428#endif 1429 ret = do_replace(sock_net(sk), arg, len); 1430 break; 1431 1432 case ARPT_SO_SET_ADD_COUNTERS: 1433 ret = do_add_counters(sock_net(sk), arg, len); 1434 break; 1435 1436 default: 1437 ret = -EINVAL; 1438 } 1439 1440 return ret; 1441} 1442 1443static int do_arpt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len) 1444{ 1445 int ret; 1446 1447 if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN)) 1448 return -EPERM; 1449 1450 switch (cmd) { 1451 case ARPT_SO_GET_INFO: 1452 ret = get_info(sock_net(sk), user, len); 1453 break; 1454 1455 case ARPT_SO_GET_ENTRIES: 1456#ifdef CONFIG_NETFILTER_XTABLES_COMPAT 1457 if (in_compat_syscall()) 1458 ret = compat_get_entries(sock_net(sk), user, len); 1459 else 1460#endif 1461 ret = get_entries(sock_net(sk), user, len); 1462 break; 1463 1464 case ARPT_SO_GET_REVISION_TARGET: { 1465 struct xt_get_revision rev; 1466 1467 if (*len != sizeof(rev)) { 1468 ret = -EINVAL; 1469 break; 1470 } 1471 if (copy_from_user(&rev, user, sizeof(rev)) != 0) { 1472 ret = -EFAULT; 1473 break; 1474 } 1475 rev.name[sizeof(rev.name)-1] = 0; 1476 1477 try_then_request_module(xt_find_revision(NFPROTO_ARP, rev.name, 1478 rev.revision, 1, &ret), 1479 "arpt_%s", rev.name); 1480 break; 1481 } 1482 1483 default: 1484 ret = -EINVAL; 1485 } 1486 1487 return ret; 1488} 1489 1490static void __arpt_unregister_table(struct net *net, struct xt_table *table) 1491{ 1492 struct xt_table_info *private; 1493 void *loc_cpu_entry; 1494 struct module *table_owner = table->me; 1495 struct arpt_entry *iter; 1496 1497 private = xt_unregister_table(table); 1498 1499 /* Decrease module usage counts and free resources */ 1500 loc_cpu_entry = private->entries; 1501 xt_entry_foreach(iter, loc_cpu_entry, private->size) 1502 cleanup_entry(iter, net); 1503 if (private->number > private->initial_entries) 1504 module_put(table_owner); 1505 xt_free_table_info(private); 1506} 1507 1508int arpt_register_table(struct net *net, 1509 const struct xt_table *table, 1510 const struct arpt_replace *repl, 1511 const struct nf_hook_ops *template_ops) 1512{ 1513 struct nf_hook_ops *ops; 1514 unsigned int num_ops; 1515 int ret, i; 1516 struct xt_table_info *newinfo; 1517 struct xt_table_info bootstrap = {0}; 1518 void *loc_cpu_entry; 1519 struct xt_table *new_table; 1520 1521 newinfo = xt_alloc_table_info(repl->size); 1522 if (!newinfo) 1523 return -ENOMEM; 1524 1525 loc_cpu_entry = newinfo->entries; 1526 memcpy(loc_cpu_entry, repl->entries, repl->size); 1527 1528 ret = translate_table(net, newinfo, loc_cpu_entry, repl); 1529 if (ret != 0) { 1530 xt_free_table_info(newinfo); 1531 return ret; 1532 } 1533 1534 new_table = xt_register_table(net, table, &bootstrap, newinfo); 1535 if (IS_ERR(new_table)) { 1536 struct arpt_entry *iter; 1537 1538 xt_entry_foreach(iter, loc_cpu_entry, newinfo->size) 1539 cleanup_entry(iter, net); 1540 xt_free_table_info(newinfo); 1541 return PTR_ERR(new_table); 1542 } 1543 1544 num_ops = hweight32(table->valid_hooks); 1545 if (num_ops == 0) { 1546 ret = -EINVAL; 1547 goto out_free; 1548 } 1549 1550 ops = kmemdup(template_ops, sizeof(*ops) * num_ops, GFP_KERNEL); 1551 if (!ops) { 1552 ret = -ENOMEM; 1553 goto out_free; 1554 } 1555 1556 for (i = 0; i < num_ops; i++) 1557 ops[i].priv = new_table; 1558 1559 new_table->ops = ops; 1560 1561 ret = nf_register_net_hooks(net, ops, num_ops); 1562 if (ret != 0) 1563 goto out_free; 1564 1565 return ret; 1566 1567out_free: 1568 __arpt_unregister_table(net, new_table); 1569 return ret; 1570} 1571 1572void arpt_unregister_table_pre_exit(struct net *net, const char *name) 1573{ 1574 struct xt_table *table = xt_find_table(net, NFPROTO_ARP, name); 1575 1576 if (table) 1577 nf_unregister_net_hooks(net, table->ops, hweight32(table->valid_hooks)); 1578} 1579EXPORT_SYMBOL(arpt_unregister_table_pre_exit); 1580 1581void arpt_unregister_table(struct net *net, const char *name) 1582{ 1583 struct xt_table *table = xt_find_table(net, NFPROTO_ARP, name); 1584 1585 if (table) 1586 __arpt_unregister_table(net, table); 1587} 1588 1589/* The built-in targets: standard (NULL) and error. */ 1590static struct xt_target arpt_builtin_tg[] __read_mostly = { 1591 { 1592 .name = XT_STANDARD_TARGET, 1593 .targetsize = sizeof(int), 1594 .family = NFPROTO_ARP, 1595#ifdef CONFIG_NETFILTER_XTABLES_COMPAT 1596 .compatsize = sizeof(compat_int_t), 1597 .compat_from_user = compat_standard_from_user, 1598 .compat_to_user = compat_standard_to_user, 1599#endif 1600 }, 1601 { 1602 .name = XT_ERROR_TARGET, 1603 .target = arpt_error, 1604 .targetsize = XT_FUNCTION_MAXNAMELEN, 1605 .family = NFPROTO_ARP, 1606 }, 1607}; 1608 1609static struct nf_sockopt_ops arpt_sockopts = { 1610 .pf = PF_INET, 1611 .set_optmin = ARPT_BASE_CTL, 1612 .set_optmax = ARPT_SO_SET_MAX+1, 1613 .set = do_arpt_set_ctl, 1614 .get_optmin = ARPT_BASE_CTL, 1615 .get_optmax = ARPT_SO_GET_MAX+1, 1616 .get = do_arpt_get_ctl, 1617 .owner = THIS_MODULE, 1618}; 1619 1620static int __net_init arp_tables_net_init(struct net *net) 1621{ 1622 return xt_proto_init(net, NFPROTO_ARP); 1623} 1624 1625static void __net_exit arp_tables_net_exit(struct net *net) 1626{ 1627 xt_proto_fini(net, NFPROTO_ARP); 1628} 1629 1630static struct pernet_operations arp_tables_net_ops = { 1631 .init = arp_tables_net_init, 1632 .exit = arp_tables_net_exit, 1633}; 1634 1635static int __init arp_tables_init(void) 1636{ 1637 int ret; 1638 1639 ret = register_pernet_subsys(&arp_tables_net_ops); 1640 if (ret < 0) 1641 goto err1; 1642 1643 /* No one else will be downing sem now, so we won't sleep */ 1644 ret = xt_register_targets(arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg)); 1645 if (ret < 0) 1646 goto err2; 1647 1648 /* Register setsockopt */ 1649 ret = nf_register_sockopt(&arpt_sockopts); 1650 if (ret < 0) 1651 goto err4; 1652 1653 return 0; 1654 1655err4: 1656 xt_unregister_targets(arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg)); 1657err2: 1658 unregister_pernet_subsys(&arp_tables_net_ops); 1659err1: 1660 return ret; 1661} 1662 1663static void __exit arp_tables_fini(void) 1664{ 1665 nf_unregister_sockopt(&arpt_sockopts); 1666 xt_unregister_targets(arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg)); 1667 unregister_pernet_subsys(&arp_tables_net_ops); 1668} 1669 1670EXPORT_SYMBOL(arpt_register_table); 1671EXPORT_SYMBOL(arpt_unregister_table); 1672EXPORT_SYMBOL(arpt_do_table); 1673 1674module_init(arp_tables_init); 1675module_exit(arp_tables_fini); 1676