1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Packet matching code. 4 * 5 * Copyright (C) 1999 Paul `Rusty' Russell & Michael J. Neuling 6 * Copyright (C) 2000-2005 Netfilter Core Team <coreteam@netfilter.org> 7 * Copyright (C) 2006-2010 Patrick McHardy <kaber@trash.net> 8 */ 9 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 10 #include <linux/cache.h> 11 #include <linux/capability.h> 12 #include <linux/skbuff.h> 13 #include <linux/kmod.h> 14 #include <linux/vmalloc.h> 15 #include <linux/netdevice.h> 16 #include <linux/module.h> 17 #include <net/ip.h> 18 #include <net/compat.h> 19 #include <linux/uaccess.h> 20 #include <linux/mutex.h> 21 #include <linux/proc_fs.h> 22 #include <linux/err.h> 23 #include <linux/cpumask.h> 24 25 #include <linux/netfilter/x_tables.h> 26 #include <linux/netfilter_ipv4/ip_tables.h> 27 #include <net/netfilter/nf_log.h> 28 #include "../../netfilter/xt_repldata.h" 29 30 MODULE_LICENSE("GPL"); 31 MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>"); 32 MODULE_DESCRIPTION("IPv4 packet filter"); 33 34 void *ipt_alloc_initial_table(const struct xt_table *info) 35 { 36 return xt_alloc_initial_table(ipt, IPT); 37 } 38 EXPORT_SYMBOL_GPL(ipt_alloc_initial_table); 39 40 /* Returns whether matches rule or not. */ 41 /* Performance critical - called for every packet */ 42 static inline bool 43 ip_packet_match(const struct iphdr *ip, 44 const char *indev, 45 const char *outdev, 46 const struct ipt_ip *ipinfo, 47 int isfrag) 48 { 49 unsigned long ret; 50 51 if (NF_INVF(ipinfo, IPT_INV_SRCIP, 52 (ip->saddr & ipinfo->smsk.s_addr) != ipinfo->src.s_addr) || 53 NF_INVF(ipinfo, IPT_INV_DSTIP, 54 (ip->daddr & ipinfo->dmsk.s_addr) != ipinfo->dst.s_addr)) 55 return false; 56 57 ret = ifname_compare_aligned(indev, ipinfo->iniface, ipinfo->iniface_mask); 58 59 if (NF_INVF(ipinfo, IPT_INV_VIA_IN, ret != 0)) 60 return false; 61 62 ret = ifname_compare_aligned(outdev, ipinfo->outiface, ipinfo->outiface_mask); 63 64 if (NF_INVF(ipinfo, IPT_INV_VIA_OUT, ret != 0)) 65 return false; 66 67 /* Check specific protocol */ 68 if (ipinfo->proto && 69 NF_INVF(ipinfo, IPT_INV_PROTO, ip->protocol != ipinfo->proto)) 70 return false; 71 72 /* If we have a fragment rule but the packet is not a fragment 73 * then we return zero */ 74 if (NF_INVF(ipinfo, IPT_INV_FRAG, 75 (ipinfo->flags & IPT_F_FRAG) && !isfrag)) 76 return false; 77 78 return true; 79 } 80 81 static bool 82 ip_checkentry(const struct ipt_ip *ip) 83 { 84 if (ip->flags & ~IPT_F_MASK) 85 return false; 86 if (ip->invflags & ~IPT_INV_MASK) 87 return false; 88 return true; 89 } 90 91 static unsigned int 92 ipt_error(struct sk_buff *skb, const struct xt_action_param *par) 93 { 94 net_info_ratelimited("error: `%s'\n", (const char *)par->targinfo); 95 96 return NF_DROP; 97 } 98 99 /* Performance critical */ 100 static inline struct ipt_entry * 101 get_entry(const void *base, unsigned int offset) 102 { 103 return (struct ipt_entry *)(base + offset); 104 } 105 106 /* All zeroes == unconditional rule. */ 107 /* Mildly perf critical (only if packet tracing is on) */ 108 static inline bool unconditional(const struct ipt_entry *e) 109 { 110 static const struct ipt_ip uncond; 111 112 return e->target_offset == sizeof(struct ipt_entry) && 113 memcmp(&e->ip, &uncond, sizeof(uncond)) == 0; 114 } 115 116 /* for const-correctness */ 117 static inline const struct xt_entry_target * 118 ipt_get_target_c(const struct ipt_entry *e) 119 { 120 return ipt_get_target((struct ipt_entry *)e); 121 } 122 123 #if IS_ENABLED(CONFIG_NETFILTER_XT_TARGET_TRACE) 124 static const char *const hooknames[] = { 125 [NF_INET_PRE_ROUTING] = "PREROUTING", 126 [NF_INET_LOCAL_IN] = "INPUT", 127 [NF_INET_FORWARD] = "FORWARD", 128 [NF_INET_LOCAL_OUT] = "OUTPUT", 129 [NF_INET_POST_ROUTING] = "POSTROUTING", 130 }; 131 132 enum nf_ip_trace_comments { 133 NF_IP_TRACE_COMMENT_RULE, 134 NF_IP_TRACE_COMMENT_RETURN, 135 NF_IP_TRACE_COMMENT_POLICY, 136 }; 137 138 static const char *const comments[] = { 139 [NF_IP_TRACE_COMMENT_RULE] = "rule", 140 [NF_IP_TRACE_COMMENT_RETURN] = "return", 141 [NF_IP_TRACE_COMMENT_POLICY] = "policy", 142 }; 143 144 static const struct nf_loginfo trace_loginfo = { 145 .type = NF_LOG_TYPE_LOG, 146 .u = { 147 .log = { 148 .level = 4, 149 .logflags = NF_LOG_DEFAULT_MASK, 150 }, 151 }, 152 }; 153 154 /* Mildly perf critical (only if packet tracing is on) */ 155 static inline int 156 get_chainname_rulenum(const struct ipt_entry *s, const struct ipt_entry *e, 157 const char *hookname, const char **chainname, 158 const char **comment, unsigned int *rulenum) 159 { 160 const struct xt_standard_target *t = (void *)ipt_get_target_c(s); 161 162 if (strcmp(t->target.u.kernel.target->name, XT_ERROR_TARGET) == 0) { 163 /* Head of user chain: ERROR target with chainname */ 164 *chainname = t->target.data; 165 (*rulenum) = 0; 166 } else if (s == e) { 167 (*rulenum)++; 168 169 if (unconditional(s) && 170 strcmp(t->target.u.kernel.target->name, 171 XT_STANDARD_TARGET) == 0 && 172 t->verdict < 0) { 173 /* Tail of chains: STANDARD target (return/policy) */ 174 *comment = *chainname == hookname 175 ? comments[NF_IP_TRACE_COMMENT_POLICY] 176 : comments[NF_IP_TRACE_COMMENT_RETURN]; 177 } 178 return 1; 179 } else 180 (*rulenum)++; 181 182 return 0; 183 } 184 185 static void trace_packet(struct net *net, 186 const struct sk_buff *skb, 187 unsigned int hook, 188 const struct net_device *in, 189 const struct net_device *out, 190 const char *tablename, 191 const struct xt_table_info *private, 192 const struct ipt_entry *e) 193 { 194 const struct ipt_entry *root; 195 const char *hookname, *chainname, *comment; 196 const struct ipt_entry *iter; 197 unsigned int rulenum = 0; 198 199 root = get_entry(private->entries, private->hook_entry[hook]); 200 201 hookname = chainname = hooknames[hook]; 202 comment = comments[NF_IP_TRACE_COMMENT_RULE]; 203 204 xt_entry_foreach(iter, root, private->size - private->hook_entry[hook]) 205 if (get_chainname_rulenum(iter, e, hookname, 206 &chainname, &comment, &rulenum) != 0) 207 break; 208 209 nf_log_trace(net, AF_INET, hook, skb, in, out, &trace_loginfo, 210 "TRACE: %s:%s:%s:%u ", 211 tablename, chainname, comment, rulenum); 212 } 213 #endif 214 215 static inline 216 struct ipt_entry *ipt_next_entry(const struct ipt_entry *entry) 217 { 218 return (void *)entry + entry->next_offset; 219 } 220 221 /* Returns one of the generic firewall policies, like NF_ACCEPT. */ 222 unsigned int 223 ipt_do_table(void *priv, 224 struct sk_buff *skb, 225 const struct nf_hook_state *state) 226 { 227 const struct xt_table *table = priv; 228 unsigned int hook = state->hook; 229 static const char nulldevname[IFNAMSIZ] __attribute__((aligned(sizeof(long)))); 230 const struct iphdr *ip; 231 /* Initializing verdict to NF_DROP keeps gcc happy. */ 232 unsigned int verdict = NF_DROP; 233 const char *indev, *outdev; 234 const void *table_base; 235 struct ipt_entry *e, **jumpstack; 236 unsigned int stackidx, cpu; 237 const struct xt_table_info *private; 238 struct xt_action_param acpar; 239 unsigned int addend; 240 241 /* Initialization */ 242 stackidx = 0; 243 ip = ip_hdr(skb); 244 indev = state->in ? state->in->name : nulldevname; 245 outdev = state->out ? state->out->name : nulldevname; 246 /* We handle fragments by dealing with the first fragment as 247 * if it was a normal packet. All other fragments are treated 248 * normally, except that they will NEVER match rules that ask 249 * things we don't know, ie. tcp syn flag or ports). If the 250 * rule is also a fragment-specific rule, non-fragments won't 251 * match it. */ 252 acpar.fragoff = ntohs(ip->frag_off) & IP_OFFSET; 253 acpar.thoff = ip_hdrlen(skb); 254 acpar.hotdrop = false; 255 acpar.state = state; 256 257 WARN_ON(!(table->valid_hooks & (1 << hook))); 258 local_bh_disable(); 259 addend = xt_write_recseq_begin(); 260 private = READ_ONCE(table->private); /* Address dependency. */ 261 cpu = smp_processor_id(); 262 table_base = private->entries; 263 jumpstack = (struct ipt_entry **)private->jumpstack[cpu]; 264 265 /* Switch to alternate jumpstack if we're being invoked via TEE. 266 * TEE issues XT_CONTINUE verdict on original skb so we must not 267 * clobber the jumpstack. 268 * 269 * For recursion via REJECT or SYNPROXY the stack will be clobbered 270 * but it is no problem since absolute verdict is issued by these. 271 */ 272 if (static_key_false(&xt_tee_enabled)) 273 jumpstack += private->stacksize * __this_cpu_read(nf_skb_duplicated); 274 275 e = get_entry(table_base, private->hook_entry[hook]); 276 277 do { 278 const struct xt_entry_target *t; 279 const struct xt_entry_match *ematch; 280 struct xt_counters *counter; 281 282 WARN_ON(!e); 283 if (!ip_packet_match(ip, indev, outdev, 284 &e->ip, acpar.fragoff)) { 285 no_match: 286 e = ipt_next_entry(e); 287 continue; 288 } 289 290 xt_ematch_foreach(ematch, e) { 291 acpar.match = ematch->u.kernel.match; 292 acpar.matchinfo = ematch->data; 293 if (!acpar.match->match(skb, &acpar)) 294 goto no_match; 295 } 296 297 counter = xt_get_this_cpu_counter(&e->counters); 298 ADD_COUNTER(*counter, skb->len, 1); 299 300 t = ipt_get_target_c(e); 301 WARN_ON(!t->u.kernel.target); 302 303 #if IS_ENABLED(CONFIG_NETFILTER_XT_TARGET_TRACE) 304 /* The packet is traced: log it */ 305 if (unlikely(skb->nf_trace)) 306 trace_packet(state->net, skb, hook, state->in, 307 state->out, table->name, private, e); 308 #endif 309 /* Standard target? */ 310 if (!t->u.kernel.target->target) { 311 int v; 312 313 v = ((struct xt_standard_target *)t)->verdict; 314 if (v < 0) { 315 /* Pop from stack? */ 316 if (v != XT_RETURN) { 317 verdict = (unsigned int)(-v) - 1; 318 break; 319 } 320 if (stackidx == 0) { 321 e = get_entry(table_base, 322 private->underflow[hook]); 323 } else { 324 e = jumpstack[--stackidx]; 325 e = ipt_next_entry(e); 326 } 327 continue; 328 } 329 if (table_base + v != ipt_next_entry(e) && 330 !(e->ip.flags & IPT_F_GOTO)) { 331 if (unlikely(stackidx >= private->stacksize)) { 332 verdict = NF_DROP; 333 break; 334 } 335 jumpstack[stackidx++] = e; 336 } 337 338 e = get_entry(table_base, v); 339 continue; 340 } 341 342 acpar.target = t->u.kernel.target; 343 acpar.targinfo = t->data; 344 345 verdict = t->u.kernel.target->target(skb, &acpar); 346 if (verdict == XT_CONTINUE) { 347 /* Target might have changed stuff. */ 348 ip = ip_hdr(skb); 349 e = ipt_next_entry(e); 350 } else { 351 /* Verdict */ 352 break; 353 } 354 } while (!acpar.hotdrop); 355 356 xt_write_recseq_end(addend); 357 local_bh_enable(); 358 359 if (acpar.hotdrop) 360 return NF_DROP; 361 else return verdict; 362 } 363 364 /* Figures out from what hook each rule can be called: returns 0 if 365 there are loops. Puts hook bitmask in comefrom. */ 366 static int 367 mark_source_chains(const struct xt_table_info *newinfo, 368 unsigned int valid_hooks, void *entry0, 369 unsigned int *offsets) 370 { 371 unsigned int hook; 372 373 /* No recursion; use packet counter to save back ptrs (reset 374 to 0 as we leave), and comefrom to save source hook bitmask */ 375 for (hook = 0; hook < NF_INET_NUMHOOKS; hook++) { 376 unsigned int pos = newinfo->hook_entry[hook]; 377 struct ipt_entry *e = entry0 + pos; 378 379 if (!(valid_hooks & (1 << hook))) 380 continue; 381 382 /* Set initial back pointer. */ 383 e->counters.pcnt = pos; 384 385 for (;;) { 386 const struct xt_standard_target *t 387 = (void *)ipt_get_target_c(e); 388 int visited = e->comefrom & (1 << hook); 389 390 if (e->comefrom & (1 << NF_INET_NUMHOOKS)) 391 return 0; 392 393 e->comefrom |= ((1 << hook) | (1 << NF_INET_NUMHOOKS)); 394 395 /* Unconditional return/END. */ 396 if ((unconditional(e) && 397 (strcmp(t->target.u.user.name, 398 XT_STANDARD_TARGET) == 0) && 399 t->verdict < 0) || visited) { 400 unsigned int oldpos, size; 401 402 /* Return: backtrack through the last 403 big jump. */ 404 do { 405 e->comefrom ^= (1<<NF_INET_NUMHOOKS); 406 oldpos = pos; 407 pos = e->counters.pcnt; 408 e->counters.pcnt = 0; 409 410 /* We're at the start. */ 411 if (pos == oldpos) 412 goto next; 413 414 e = entry0 + pos; 415 } while (oldpos == pos + e->next_offset); 416 417 /* Move along one */ 418 size = e->next_offset; 419 e = entry0 + pos + size; 420 if (pos + size >= newinfo->size) 421 return 0; 422 e->counters.pcnt = pos; 423 pos += size; 424 } else { 425 int newpos = t->verdict; 426 427 if (strcmp(t->target.u.user.name, 428 XT_STANDARD_TARGET) == 0 && 429 newpos >= 0) { 430 /* This a jump; chase it. */ 431 if (!xt_find_jump_offset(offsets, newpos, 432 newinfo->number)) 433 return 0; 434 } else { 435 /* ... this is a fallthru */ 436 newpos = pos + e->next_offset; 437 if (newpos >= newinfo->size) 438 return 0; 439 } 440 e = entry0 + newpos; 441 e->counters.pcnt = pos; 442 pos = newpos; 443 } 444 } 445 next: ; 446 } 447 return 1; 448 } 449 450 static void cleanup_match(struct xt_entry_match *m, struct net *net) 451 { 452 struct xt_mtdtor_param par; 453 454 par.net = net; 455 par.match = m->u.kernel.match; 456 par.matchinfo = m->data; 457 par.family = NFPROTO_IPV4; 458 if (par.match->destroy != NULL) 459 par.match->destroy(&par); 460 module_put(par.match->me); 461 } 462 463 static int 464 check_match(struct xt_entry_match *m, struct xt_mtchk_param *par) 465 { 466 const struct ipt_ip *ip = par->entryinfo; 467 468 par->match = m->u.kernel.match; 469 par->matchinfo = m->data; 470 471 return xt_check_match(par, m->u.match_size - sizeof(*m), 472 ip->proto, ip->invflags & IPT_INV_PROTO); 473 } 474 475 static int 476 find_check_match(struct xt_entry_match *m, struct xt_mtchk_param *par) 477 { 478 struct xt_match *match; 479 int ret; 480 481 match = xt_request_find_match(NFPROTO_IPV4, m->u.user.name, 482 m->u.user.revision); 483 if (IS_ERR(match)) 484 return PTR_ERR(match); 485 m->u.kernel.match = match; 486 487 ret = check_match(m, par); 488 if (ret) 489 goto err; 490 491 return 0; 492 err: 493 module_put(m->u.kernel.match->me); 494 return ret; 495 } 496 497 static int check_target(struct ipt_entry *e, struct net *net, const char *name) 498 { 499 struct xt_entry_target *t = ipt_get_target(e); 500 struct xt_tgchk_param par = { 501 .net = net, 502 .table = name, 503 .entryinfo = e, 504 .target = t->u.kernel.target, 505 .targinfo = t->data, 506 .hook_mask = e->comefrom, 507 .family = NFPROTO_IPV4, 508 }; 509 510 return xt_check_target(&par, t->u.target_size - sizeof(*t), 511 e->ip.proto, e->ip.invflags & IPT_INV_PROTO); 512 } 513 514 static int 515 find_check_entry(struct ipt_entry *e, struct net *net, const char *name, 516 unsigned int size, 517 struct xt_percpu_counter_alloc_state *alloc_state) 518 { 519 struct xt_entry_target *t; 520 struct xt_target *target; 521 int ret; 522 unsigned int j; 523 struct xt_mtchk_param mtpar; 524 struct xt_entry_match *ematch; 525 526 if (!xt_percpu_counter_alloc(alloc_state, &e->counters)) 527 return -ENOMEM; 528 529 j = 0; 530 memset(&mtpar, 0, sizeof(mtpar)); 531 mtpar.net = net; 532 mtpar.table = name; 533 mtpar.entryinfo = &e->ip; 534 mtpar.hook_mask = e->comefrom; 535 mtpar.family = NFPROTO_IPV4; 536 xt_ematch_foreach(ematch, e) { 537 ret = find_check_match(ematch, &mtpar); 538 if (ret != 0) 539 goto cleanup_matches; 540 ++j; 541 } 542 543 t = ipt_get_target(e); 544 target = xt_request_find_target(NFPROTO_IPV4, t->u.user.name, 545 t->u.user.revision); 546 if (IS_ERR(target)) { 547 ret = PTR_ERR(target); 548 goto cleanup_matches; 549 } 550 t->u.kernel.target = target; 551 552 ret = check_target(e, net, name); 553 if (ret) 554 goto err; 555 556 return 0; 557 err: 558 module_put(t->u.kernel.target->me); 559 cleanup_matches: 560 xt_ematch_foreach(ematch, e) { 561 if (j-- == 0) 562 break; 563 cleanup_match(ematch, net); 564 } 565 566 xt_percpu_counter_free(&e->counters); 567 568 return ret; 569 } 570 571 static bool check_underflow(const struct ipt_entry *e) 572 { 573 const struct xt_entry_target *t; 574 unsigned int verdict; 575 576 if (!unconditional(e)) 577 return false; 578 t = ipt_get_target_c(e); 579 if (strcmp(t->u.user.name, XT_STANDARD_TARGET) != 0) 580 return false; 581 verdict = ((struct xt_standard_target *)t)->verdict; 582 verdict = -verdict - 1; 583 return verdict == NF_DROP || verdict == NF_ACCEPT; 584 } 585 586 static int 587 check_entry_size_and_hooks(struct ipt_entry *e, 588 struct xt_table_info *newinfo, 589 const unsigned char *base, 590 const unsigned char *limit, 591 const unsigned int *hook_entries, 592 const unsigned int *underflows, 593 unsigned int valid_hooks) 594 { 595 unsigned int h; 596 int err; 597 598 if ((unsigned long)e % __alignof__(struct ipt_entry) != 0 || 599 (unsigned char *)e + sizeof(struct ipt_entry) >= limit || 600 (unsigned char *)e + e->next_offset > limit) 601 return -EINVAL; 602 603 if (e->next_offset 604 < sizeof(struct ipt_entry) + sizeof(struct xt_entry_target)) 605 return -EINVAL; 606 607 if (!ip_checkentry(&e->ip)) 608 return -EINVAL; 609 610 err = xt_check_entry_offsets(e, e->elems, e->target_offset, 611 e->next_offset); 612 if (err) 613 return err; 614 615 /* Check hooks & underflows */ 616 for (h = 0; h < NF_INET_NUMHOOKS; h++) { 617 if (!(valid_hooks & (1 << h))) 618 continue; 619 if ((unsigned char *)e - base == hook_entries[h]) 620 newinfo->hook_entry[h] = hook_entries[h]; 621 if ((unsigned char *)e - base == underflows[h]) { 622 if (!check_underflow(e)) 623 return -EINVAL; 624 625 newinfo->underflow[h] = underflows[h]; 626 } 627 } 628 629 /* Clear counters and comefrom */ 630 e->counters = ((struct xt_counters) { 0, 0 }); 631 e->comefrom = 0; 632 return 0; 633 } 634 635 static void 636 cleanup_entry(struct ipt_entry *e, struct net *net) 637 { 638 struct xt_tgdtor_param par; 639 struct xt_entry_target *t; 640 struct xt_entry_match *ematch; 641 642 /* Cleanup all matches */ 643 xt_ematch_foreach(ematch, e) 644 cleanup_match(ematch, net); 645 t = ipt_get_target(e); 646 647 par.net = net; 648 par.target = t->u.kernel.target; 649 par.targinfo = t->data; 650 par.family = NFPROTO_IPV4; 651 if (par.target->destroy != NULL) 652 par.target->destroy(&par); 653 module_put(par.target->me); 654 xt_percpu_counter_free(&e->counters); 655 } 656 657 /* Checks and translates the user-supplied table segment (held in 658 newinfo) */ 659 static int 660 translate_table(struct net *net, struct xt_table_info *newinfo, void *entry0, 661 const struct ipt_replace *repl) 662 { 663 struct xt_percpu_counter_alloc_state alloc_state = { 0 }; 664 struct ipt_entry *iter; 665 unsigned int *offsets; 666 unsigned int i; 667 int ret = 0; 668 669 newinfo->size = repl->size; 670 newinfo->number = repl->num_entries; 671 672 /* Init all hooks to impossible value. */ 673 for (i = 0; i < NF_INET_NUMHOOKS; i++) { 674 newinfo->hook_entry[i] = 0xFFFFFFFF; 675 newinfo->underflow[i] = 0xFFFFFFFF; 676 } 677 678 offsets = xt_alloc_entry_offsets(newinfo->number); 679 if (!offsets) 680 return -ENOMEM; 681 i = 0; 682 /* Walk through entries, checking offsets. */ 683 xt_entry_foreach(iter, entry0, newinfo->size) { 684 ret = check_entry_size_and_hooks(iter, newinfo, entry0, 685 entry0 + repl->size, 686 repl->hook_entry, 687 repl->underflow, 688 repl->valid_hooks); 689 if (ret != 0) 690 goto out_free; 691 if (i < repl->num_entries) 692 offsets[i] = (void *)iter - entry0; 693 ++i; 694 if (strcmp(ipt_get_target(iter)->u.user.name, 695 XT_ERROR_TARGET) == 0) 696 ++newinfo->stacksize; 697 } 698 699 ret = -EINVAL; 700 if (i != repl->num_entries) 701 goto out_free; 702 703 ret = xt_check_table_hooks(newinfo, repl->valid_hooks); 704 if (ret) 705 goto out_free; 706 707 if (!mark_source_chains(newinfo, repl->valid_hooks, entry0, offsets)) { 708 ret = -ELOOP; 709 goto out_free; 710 } 711 kvfree(offsets); 712 713 /* Finally, each sanity check must pass */ 714 i = 0; 715 xt_entry_foreach(iter, entry0, newinfo->size) { 716 ret = find_check_entry(iter, net, repl->name, repl->size, 717 &alloc_state); 718 if (ret != 0) 719 break; 720 ++i; 721 } 722 723 if (ret != 0) { 724 xt_entry_foreach(iter, entry0, newinfo->size) { 725 if (i-- == 0) 726 break; 727 cleanup_entry(iter, net); 728 } 729 return ret; 730 } 731 732 return ret; 733 out_free: 734 kvfree(offsets); 735 return ret; 736 } 737 738 static void 739 get_counters(const struct xt_table_info *t, 740 struct xt_counters counters[]) 741 { 742 struct ipt_entry *iter; 743 unsigned int cpu; 744 unsigned int i; 745 746 for_each_possible_cpu(cpu) { 747 seqcount_t *s = &per_cpu(xt_recseq, cpu); 748 749 i = 0; 750 xt_entry_foreach(iter, t->entries, t->size) { 751 struct xt_counters *tmp; 752 u64 bcnt, pcnt; 753 unsigned int start; 754 755 tmp = xt_get_per_cpu_counter(&iter->counters, cpu); 756 do { 757 start = read_seqcount_begin(s); 758 bcnt = tmp->bcnt; 759 pcnt = tmp->pcnt; 760 } while (read_seqcount_retry(s, start)); 761 762 ADD_COUNTER(counters[i], bcnt, pcnt); 763 ++i; /* macro does multi eval of i */ 764 cond_resched(); 765 } 766 } 767 } 768 769 static void get_old_counters(const struct xt_table_info *t, 770 struct xt_counters counters[]) 771 { 772 struct ipt_entry *iter; 773 unsigned int cpu, i; 774 775 for_each_possible_cpu(cpu) { 776 i = 0; 777 xt_entry_foreach(iter, t->entries, t->size) { 778 const struct xt_counters *tmp; 779 780 tmp = xt_get_per_cpu_counter(&iter->counters, cpu); 781 ADD_COUNTER(counters[i], tmp->bcnt, tmp->pcnt); 782 ++i; /* macro does multi eval of i */ 783 } 784 785 cond_resched(); 786 } 787 } 788 789 static struct xt_counters *alloc_counters(const struct xt_table *table) 790 { 791 unsigned int countersize; 792 struct xt_counters *counters; 793 const struct xt_table_info *private = table->private; 794 795 /* We need atomic snapshot of counters: rest doesn't change 796 (other than comefrom, which userspace doesn't care 797 about). */ 798 countersize = sizeof(struct xt_counters) * private->number; 799 counters = vzalloc(countersize); 800 801 if (counters == NULL) 802 return ERR_PTR(-ENOMEM); 803 804 get_counters(private, counters); 805 806 return counters; 807 } 808 809 static int 810 copy_entries_to_user(unsigned int total_size, 811 const struct xt_table *table, 812 void __user *userptr) 813 { 814 unsigned int off, num; 815 const struct ipt_entry *e; 816 struct xt_counters *counters; 817 const struct xt_table_info *private = table->private; 818 int ret = 0; 819 const void *loc_cpu_entry; 820 821 counters = alloc_counters(table); 822 if (IS_ERR(counters)) 823 return PTR_ERR(counters); 824 825 loc_cpu_entry = private->entries; 826 827 /* FIXME: use iterator macros --RR */ 828 /* ... then go back and fix counters and names */ 829 for (off = 0, num = 0; off < total_size; off += e->next_offset, num++){ 830 unsigned int i; 831 const struct xt_entry_match *m; 832 const struct xt_entry_target *t; 833 834 e = loc_cpu_entry + off; 835 if (copy_to_user(userptr + off, e, sizeof(*e))) { 836 ret = -EFAULT; 837 goto free_counters; 838 } 839 if (copy_to_user(userptr + off 840 + offsetof(struct ipt_entry, counters), 841 &counters[num], 842 sizeof(counters[num])) != 0) { 843 ret = -EFAULT; 844 goto free_counters; 845 } 846 847 for (i = sizeof(struct ipt_entry); 848 i < e->target_offset; 849 i += m->u.match_size) { 850 m = (void *)e + i; 851 852 if (xt_match_to_user(m, userptr + off + i)) { 853 ret = -EFAULT; 854 goto free_counters; 855 } 856 } 857 858 t = ipt_get_target_c(e); 859 if (xt_target_to_user(t, userptr + off + e->target_offset)) { 860 ret = -EFAULT; 861 goto free_counters; 862 } 863 } 864 865 free_counters: 866 vfree(counters); 867 return ret; 868 } 869 870 #ifdef CONFIG_NETFILTER_XTABLES_COMPAT 871 static void compat_standard_from_user(void *dst, const void *src) 872 { 873 int v = *(compat_int_t *)src; 874 875 if (v > 0) 876 v += xt_compat_calc_jump(AF_INET, v); 877 memcpy(dst, &v, sizeof(v)); 878 } 879 880 static int compat_standard_to_user(void __user *dst, const void *src) 881 { 882 compat_int_t cv = *(int *)src; 883 884 if (cv > 0) 885 cv -= xt_compat_calc_jump(AF_INET, cv); 886 return copy_to_user(dst, &cv, sizeof(cv)) ? -EFAULT : 0; 887 } 888 889 static int compat_calc_entry(const struct ipt_entry *e, 890 const struct xt_table_info *info, 891 const void *base, struct xt_table_info *newinfo) 892 { 893 const struct xt_entry_match *ematch; 894 const struct xt_entry_target *t; 895 unsigned int entry_offset; 896 int off, i, ret; 897 898 off = sizeof(struct ipt_entry) - sizeof(struct compat_ipt_entry); 899 entry_offset = (void *)e - base; 900 xt_ematch_foreach(ematch, e) 901 off += xt_compat_match_offset(ematch->u.kernel.match); 902 t = ipt_get_target_c(e); 903 off += xt_compat_target_offset(t->u.kernel.target); 904 newinfo->size -= off; 905 ret = xt_compat_add_offset(AF_INET, entry_offset, off); 906 if (ret) 907 return ret; 908 909 for (i = 0; i < NF_INET_NUMHOOKS; i++) { 910 if (info->hook_entry[i] && 911 (e < (struct ipt_entry *)(base + info->hook_entry[i]))) 912 newinfo->hook_entry[i] -= off; 913 if (info->underflow[i] && 914 (e < (struct ipt_entry *)(base + info->underflow[i]))) 915 newinfo->underflow[i] -= off; 916 } 917 return 0; 918 } 919 920 static int compat_table_info(const struct xt_table_info *info, 921 struct xt_table_info *newinfo) 922 { 923 struct ipt_entry *iter; 924 const void *loc_cpu_entry; 925 int ret; 926 927 if (!newinfo || !info) 928 return -EINVAL; 929 930 /* we dont care about newinfo->entries */ 931 memcpy(newinfo, info, offsetof(struct xt_table_info, entries)); 932 newinfo->initial_entries = 0; 933 loc_cpu_entry = info->entries; 934 ret = xt_compat_init_offsets(AF_INET, info->number); 935 if (ret) 936 return ret; 937 xt_entry_foreach(iter, loc_cpu_entry, info->size) { 938 ret = compat_calc_entry(iter, info, loc_cpu_entry, newinfo); 939 if (ret != 0) 940 return ret; 941 } 942 return 0; 943 } 944 #endif 945 946 static int get_info(struct net *net, void __user *user, const int *len) 947 { 948 char name[XT_TABLE_MAXNAMELEN]; 949 struct xt_table *t; 950 int ret; 951 952 if (*len != sizeof(struct ipt_getinfo)) 953 return -EINVAL; 954 955 if (copy_from_user(name, user, sizeof(name)) != 0) 956 return -EFAULT; 957 958 name[XT_TABLE_MAXNAMELEN-1] = '\0'; 959 #ifdef CONFIG_NETFILTER_XTABLES_COMPAT 960 if (in_compat_syscall()) 961 xt_compat_lock(AF_INET); 962 #endif 963 t = xt_request_find_table_lock(net, AF_INET, name); 964 if (!IS_ERR(t)) { 965 struct ipt_getinfo info; 966 const struct xt_table_info *private = t->private; 967 #ifdef CONFIG_NETFILTER_XTABLES_COMPAT 968 struct xt_table_info tmp; 969 970 if (in_compat_syscall()) { 971 ret = compat_table_info(private, &tmp); 972 xt_compat_flush_offsets(AF_INET); 973 private = &tmp; 974 } 975 #endif 976 memset(&info, 0, sizeof(info)); 977 info.valid_hooks = t->valid_hooks; 978 memcpy(info.hook_entry, private->hook_entry, 979 sizeof(info.hook_entry)); 980 memcpy(info.underflow, private->underflow, 981 sizeof(info.underflow)); 982 info.num_entries = private->number; 983 info.size = private->size; 984 strcpy(info.name, name); 985 986 if (copy_to_user(user, &info, *len) != 0) 987 ret = -EFAULT; 988 else 989 ret = 0; 990 991 xt_table_unlock(t); 992 module_put(t->me); 993 } else 994 ret = PTR_ERR(t); 995 #ifdef CONFIG_NETFILTER_XTABLES_COMPAT 996 if (in_compat_syscall()) 997 xt_compat_unlock(AF_INET); 998 #endif 999 return ret; 1000 } 1001 1002 static int 1003 get_entries(struct net *net, struct ipt_get_entries __user *uptr, 1004 const int *len) 1005 { 1006 int ret; 1007 struct ipt_get_entries get; 1008 struct xt_table *t; 1009 1010 if (*len < sizeof(get)) 1011 return -EINVAL; 1012 if (copy_from_user(&get, uptr, sizeof(get)) != 0) 1013 return -EFAULT; 1014 if (*len != sizeof(struct ipt_get_entries) + get.size) 1015 return -EINVAL; 1016 get.name[sizeof(get.name) - 1] = '\0'; 1017 1018 t = xt_find_table_lock(net, AF_INET, get.name); 1019 if (!IS_ERR(t)) { 1020 const struct xt_table_info *private = t->private; 1021 if (get.size == private->size) 1022 ret = copy_entries_to_user(private->size, 1023 t, uptr->entrytable); 1024 else 1025 ret = -EAGAIN; 1026 1027 module_put(t->me); 1028 xt_table_unlock(t); 1029 } else 1030 ret = PTR_ERR(t); 1031 1032 return ret; 1033 } 1034 1035 static int 1036 __do_replace(struct net *net, const char *name, unsigned int valid_hooks, 1037 struct xt_table_info *newinfo, unsigned int num_counters, 1038 void __user *counters_ptr) 1039 { 1040 int ret; 1041 struct xt_table *t; 1042 struct xt_table_info *oldinfo; 1043 struct xt_counters *counters; 1044 struct ipt_entry *iter; 1045 1046 counters = xt_counters_alloc(num_counters); 1047 if (!counters) { 1048 ret = -ENOMEM; 1049 goto out; 1050 } 1051 1052 t = xt_request_find_table_lock(net, AF_INET, name); 1053 if (IS_ERR(t)) { 1054 ret = PTR_ERR(t); 1055 goto free_newinfo_counters_untrans; 1056 } 1057 1058 /* You lied! */ 1059 if (valid_hooks != t->valid_hooks) { 1060 ret = -EINVAL; 1061 goto put_module; 1062 } 1063 1064 oldinfo = xt_replace_table(t, num_counters, newinfo, &ret); 1065 if (!oldinfo) 1066 goto put_module; 1067 1068 /* Update module usage count based on number of rules */ 1069 if ((oldinfo->number > oldinfo->initial_entries) || 1070 (newinfo->number <= oldinfo->initial_entries)) 1071 module_put(t->me); 1072 if ((oldinfo->number > oldinfo->initial_entries) && 1073 (newinfo->number <= oldinfo->initial_entries)) 1074 module_put(t->me); 1075 1076 xt_table_unlock(t); 1077 1078 get_old_counters(oldinfo, counters); 1079 1080 /* Decrease module usage counts and free resource */ 1081 xt_entry_foreach(iter, oldinfo->entries, oldinfo->size) 1082 cleanup_entry(iter, net); 1083 1084 xt_free_table_info(oldinfo); 1085 if (copy_to_user(counters_ptr, counters, 1086 sizeof(struct xt_counters) * num_counters) != 0) { 1087 /* Silent error, can't fail, new table is already in place */ 1088 net_warn_ratelimited("iptables: counters copy to user failed while replacing table\n"); 1089 } 1090 vfree(counters); 1091 return 0; 1092 1093 put_module: 1094 module_put(t->me); 1095 xt_table_unlock(t); 1096 free_newinfo_counters_untrans: 1097 vfree(counters); 1098 out: 1099 return ret; 1100 } 1101 1102 static int 1103 do_replace(struct net *net, sockptr_t arg, unsigned int len) 1104 { 1105 int ret; 1106 struct ipt_replace tmp; 1107 struct xt_table_info *newinfo; 1108 void *loc_cpu_entry; 1109 struct ipt_entry *iter; 1110 1111 if (copy_from_sockptr(&tmp, arg, sizeof(tmp)) != 0) 1112 return -EFAULT; 1113 1114 /* overflow check */ 1115 if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters)) 1116 return -ENOMEM; 1117 if (tmp.num_counters == 0) 1118 return -EINVAL; 1119 1120 tmp.name[sizeof(tmp.name)-1] = 0; 1121 1122 newinfo = xt_alloc_table_info(tmp.size); 1123 if (!newinfo) 1124 return -ENOMEM; 1125 1126 loc_cpu_entry = newinfo->entries; 1127 if (copy_from_sockptr_offset(loc_cpu_entry, arg, sizeof(tmp), 1128 tmp.size) != 0) { 1129 ret = -EFAULT; 1130 goto free_newinfo; 1131 } 1132 1133 ret = translate_table(net, newinfo, loc_cpu_entry, &tmp); 1134 if (ret != 0) 1135 goto free_newinfo; 1136 1137 ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo, 1138 tmp.num_counters, tmp.counters); 1139 if (ret) 1140 goto free_newinfo_untrans; 1141 return 0; 1142 1143 free_newinfo_untrans: 1144 xt_entry_foreach(iter, loc_cpu_entry, newinfo->size) 1145 cleanup_entry(iter, net); 1146 free_newinfo: 1147 xt_free_table_info(newinfo); 1148 return ret; 1149 } 1150 1151 static int 1152 do_add_counters(struct net *net, sockptr_t arg, unsigned int len) 1153 { 1154 unsigned int i; 1155 struct xt_counters_info tmp; 1156 struct xt_counters *paddc; 1157 struct xt_table *t; 1158 const struct xt_table_info *private; 1159 int ret = 0; 1160 struct ipt_entry *iter; 1161 unsigned int addend; 1162 1163 paddc = xt_copy_counters(arg, len, &tmp); 1164 if (IS_ERR(paddc)) 1165 return PTR_ERR(paddc); 1166 1167 t = xt_find_table_lock(net, AF_INET, tmp.name); 1168 if (IS_ERR(t)) { 1169 ret = PTR_ERR(t); 1170 goto free; 1171 } 1172 1173 local_bh_disable(); 1174 private = t->private; 1175 if (private->number != tmp.num_counters) { 1176 ret = -EINVAL; 1177 goto unlock_up_free; 1178 } 1179 1180 i = 0; 1181 addend = xt_write_recseq_begin(); 1182 xt_entry_foreach(iter, private->entries, private->size) { 1183 struct xt_counters *tmp; 1184 1185 tmp = xt_get_this_cpu_counter(&iter->counters); 1186 ADD_COUNTER(*tmp, paddc[i].bcnt, paddc[i].pcnt); 1187 ++i; 1188 } 1189 xt_write_recseq_end(addend); 1190 unlock_up_free: 1191 local_bh_enable(); 1192 xt_table_unlock(t); 1193 module_put(t->me); 1194 free: 1195 vfree(paddc); 1196 1197 return ret; 1198 } 1199 1200 #ifdef CONFIG_NETFILTER_XTABLES_COMPAT 1201 struct compat_ipt_replace { 1202 char name[XT_TABLE_MAXNAMELEN]; 1203 u32 valid_hooks; 1204 u32 num_entries; 1205 u32 size; 1206 u32 hook_entry[NF_INET_NUMHOOKS]; 1207 u32 underflow[NF_INET_NUMHOOKS]; 1208 u32 num_counters; 1209 compat_uptr_t counters; /* struct xt_counters * */ 1210 struct compat_ipt_entry entries[]; 1211 }; 1212 1213 static int 1214 compat_copy_entry_to_user(struct ipt_entry *e, void __user **dstptr, 1215 unsigned int *size, struct xt_counters *counters, 1216 unsigned int i) 1217 { 1218 struct xt_entry_target *t; 1219 struct compat_ipt_entry __user *ce; 1220 u_int16_t target_offset, next_offset; 1221 compat_uint_t origsize; 1222 const struct xt_entry_match *ematch; 1223 int ret = 0; 1224 1225 origsize = *size; 1226 ce = *dstptr; 1227 if (copy_to_user(ce, e, sizeof(struct ipt_entry)) != 0 || 1228 copy_to_user(&ce->counters, &counters[i], 1229 sizeof(counters[i])) != 0) 1230 return -EFAULT; 1231 1232 *dstptr += sizeof(struct compat_ipt_entry); 1233 *size -= sizeof(struct ipt_entry) - sizeof(struct compat_ipt_entry); 1234 1235 xt_ematch_foreach(ematch, e) { 1236 ret = xt_compat_match_to_user(ematch, dstptr, size); 1237 if (ret != 0) 1238 return ret; 1239 } 1240 target_offset = e->target_offset - (origsize - *size); 1241 t = ipt_get_target(e); 1242 ret = xt_compat_target_to_user(t, dstptr, size); 1243 if (ret) 1244 return ret; 1245 next_offset = e->next_offset - (origsize - *size); 1246 if (put_user(target_offset, &ce->target_offset) != 0 || 1247 put_user(next_offset, &ce->next_offset) != 0) 1248 return -EFAULT; 1249 return 0; 1250 } 1251 1252 static int 1253 compat_find_calc_match(struct xt_entry_match *m, 1254 const struct ipt_ip *ip, 1255 int *size) 1256 { 1257 struct xt_match *match; 1258 1259 match = xt_request_find_match(NFPROTO_IPV4, m->u.user.name, 1260 m->u.user.revision); 1261 if (IS_ERR(match)) 1262 return PTR_ERR(match); 1263 1264 m->u.kernel.match = match; 1265 *size += xt_compat_match_offset(match); 1266 return 0; 1267 } 1268 1269 static void compat_release_entry(struct compat_ipt_entry *e) 1270 { 1271 struct xt_entry_target *t; 1272 struct xt_entry_match *ematch; 1273 1274 /* Cleanup all matches */ 1275 xt_ematch_foreach(ematch, e) 1276 module_put(ematch->u.kernel.match->me); 1277 t = compat_ipt_get_target(e); 1278 module_put(t->u.kernel.target->me); 1279 } 1280 1281 static int 1282 check_compat_entry_size_and_hooks(struct compat_ipt_entry *e, 1283 struct xt_table_info *newinfo, 1284 unsigned int *size, 1285 const unsigned char *base, 1286 const unsigned char *limit) 1287 { 1288 struct xt_entry_match *ematch; 1289 struct xt_entry_target *t; 1290 struct xt_target *target; 1291 unsigned int entry_offset; 1292 unsigned int j; 1293 int ret, off; 1294 1295 if ((unsigned long)e % __alignof__(struct compat_ipt_entry) != 0 || 1296 (unsigned char *)e + sizeof(struct compat_ipt_entry) >= limit || 1297 (unsigned char *)e + e->next_offset > limit) 1298 return -EINVAL; 1299 1300 if (e->next_offset < sizeof(struct compat_ipt_entry) + 1301 sizeof(struct compat_xt_entry_target)) 1302 return -EINVAL; 1303 1304 if (!ip_checkentry(&e->ip)) 1305 return -EINVAL; 1306 1307 ret = xt_compat_check_entry_offsets(e, e->elems, 1308 e->target_offset, e->next_offset); 1309 if (ret) 1310 return ret; 1311 1312 off = sizeof(struct ipt_entry) - sizeof(struct compat_ipt_entry); 1313 entry_offset = (void *)e - (void *)base; 1314 j = 0; 1315 xt_ematch_foreach(ematch, e) { 1316 ret = compat_find_calc_match(ematch, &e->ip, &off); 1317 if (ret != 0) 1318 goto release_matches; 1319 ++j; 1320 } 1321 1322 t = compat_ipt_get_target(e); 1323 target = xt_request_find_target(NFPROTO_IPV4, t->u.user.name, 1324 t->u.user.revision); 1325 if (IS_ERR(target)) { 1326 ret = PTR_ERR(target); 1327 goto release_matches; 1328 } 1329 t->u.kernel.target = target; 1330 1331 off += xt_compat_target_offset(target); 1332 *size += off; 1333 ret = xt_compat_add_offset(AF_INET, entry_offset, off); 1334 if (ret) 1335 goto out; 1336 1337 return 0; 1338 1339 out: 1340 module_put(t->u.kernel.target->me); 1341 release_matches: 1342 xt_ematch_foreach(ematch, e) { 1343 if (j-- == 0) 1344 break; 1345 module_put(ematch->u.kernel.match->me); 1346 } 1347 return ret; 1348 } 1349 1350 static void 1351 compat_copy_entry_from_user(struct compat_ipt_entry *e, void **dstptr, 1352 unsigned int *size, 1353 struct xt_table_info *newinfo, unsigned char *base) 1354 { 1355 struct xt_entry_target *t; 1356 struct ipt_entry *de; 1357 unsigned int origsize; 1358 int h; 1359 struct xt_entry_match *ematch; 1360 1361 origsize = *size; 1362 de = *dstptr; 1363 memcpy(de, e, sizeof(struct ipt_entry)); 1364 memcpy(&de->counters, &e->counters, sizeof(e->counters)); 1365 1366 *dstptr += sizeof(struct ipt_entry); 1367 *size += sizeof(struct ipt_entry) - sizeof(struct compat_ipt_entry); 1368 1369 xt_ematch_foreach(ematch, e) 1370 xt_compat_match_from_user(ematch, dstptr, size); 1371 1372 de->target_offset = e->target_offset - (origsize - *size); 1373 t = compat_ipt_get_target(e); 1374 xt_compat_target_from_user(t, dstptr, size); 1375 1376 de->next_offset = e->next_offset - (origsize - *size); 1377 1378 for (h = 0; h < NF_INET_NUMHOOKS; h++) { 1379 if ((unsigned char *)de - base < newinfo->hook_entry[h]) 1380 newinfo->hook_entry[h] -= origsize - *size; 1381 if ((unsigned char *)de - base < newinfo->underflow[h]) 1382 newinfo->underflow[h] -= origsize - *size; 1383 } 1384 } 1385 1386 static int 1387 translate_compat_table(struct net *net, 1388 struct xt_table_info **pinfo, 1389 void **pentry0, 1390 const struct compat_ipt_replace *compatr) 1391 { 1392 unsigned int i, j; 1393 struct xt_table_info *newinfo, *info; 1394 void *pos, *entry0, *entry1; 1395 struct compat_ipt_entry *iter0; 1396 struct ipt_replace repl; 1397 unsigned int size; 1398 int ret; 1399 1400 info = *pinfo; 1401 entry0 = *pentry0; 1402 size = compatr->size; 1403 info->number = compatr->num_entries; 1404 1405 j = 0; 1406 xt_compat_lock(AF_INET); 1407 ret = xt_compat_init_offsets(AF_INET, compatr->num_entries); 1408 if (ret) 1409 goto out_unlock; 1410 /* Walk through entries, checking offsets. */ 1411 xt_entry_foreach(iter0, entry0, compatr->size) { 1412 ret = check_compat_entry_size_and_hooks(iter0, info, &size, 1413 entry0, 1414 entry0 + compatr->size); 1415 if (ret != 0) 1416 goto out_unlock; 1417 ++j; 1418 } 1419 1420 ret = -EINVAL; 1421 if (j != compatr->num_entries) 1422 goto out_unlock; 1423 1424 ret = -ENOMEM; 1425 newinfo = xt_alloc_table_info(size); 1426 if (!newinfo) 1427 goto out_unlock; 1428 1429 memset(newinfo->entries, 0, size); 1430 1431 newinfo->number = compatr->num_entries; 1432 for (i = 0; i < NF_INET_NUMHOOKS; i++) { 1433 newinfo->hook_entry[i] = compatr->hook_entry[i]; 1434 newinfo->underflow[i] = compatr->underflow[i]; 1435 } 1436 entry1 = newinfo->entries; 1437 pos = entry1; 1438 size = compatr->size; 1439 xt_entry_foreach(iter0, entry0, compatr->size) 1440 compat_copy_entry_from_user(iter0, &pos, &size, 1441 newinfo, entry1); 1442 1443 /* all module references in entry0 are now gone. 1444 * entry1/newinfo contains a 64bit ruleset that looks exactly as 1445 * generated by 64bit userspace. 1446 * 1447 * Call standard translate_table() to validate all hook_entrys, 1448 * underflows, check for loops, etc. 1449 */ 1450 xt_compat_flush_offsets(AF_INET); 1451 xt_compat_unlock(AF_INET); 1452 1453 memcpy(&repl, compatr, sizeof(*compatr)); 1454 1455 for (i = 0; i < NF_INET_NUMHOOKS; i++) { 1456 repl.hook_entry[i] = newinfo->hook_entry[i]; 1457 repl.underflow[i] = newinfo->underflow[i]; 1458 } 1459 1460 repl.num_counters = 0; 1461 repl.counters = NULL; 1462 repl.size = newinfo->size; 1463 ret = translate_table(net, newinfo, entry1, &repl); 1464 if (ret) 1465 goto free_newinfo; 1466 1467 *pinfo = newinfo; 1468 *pentry0 = entry1; 1469 xt_free_table_info(info); 1470 return 0; 1471 1472 free_newinfo: 1473 xt_free_table_info(newinfo); 1474 return ret; 1475 out_unlock: 1476 xt_compat_flush_offsets(AF_INET); 1477 xt_compat_unlock(AF_INET); 1478 xt_entry_foreach(iter0, entry0, compatr->size) { 1479 if (j-- == 0) 1480 break; 1481 compat_release_entry(iter0); 1482 } 1483 return ret; 1484 } 1485 1486 static int 1487 compat_do_replace(struct net *net, sockptr_t arg, unsigned int len) 1488 { 1489 int ret; 1490 struct compat_ipt_replace tmp; 1491 struct xt_table_info *newinfo; 1492 void *loc_cpu_entry; 1493 struct ipt_entry *iter; 1494 1495 if (copy_from_sockptr(&tmp, arg, sizeof(tmp)) != 0) 1496 return -EFAULT; 1497 1498 /* overflow check */ 1499 if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters)) 1500 return -ENOMEM; 1501 if (tmp.num_counters == 0) 1502 return -EINVAL; 1503 1504 tmp.name[sizeof(tmp.name)-1] = 0; 1505 1506 newinfo = xt_alloc_table_info(tmp.size); 1507 if (!newinfo) 1508 return -ENOMEM; 1509 1510 loc_cpu_entry = newinfo->entries; 1511 if (copy_from_sockptr_offset(loc_cpu_entry, arg, sizeof(tmp), 1512 tmp.size) != 0) { 1513 ret = -EFAULT; 1514 goto free_newinfo; 1515 } 1516 1517 ret = translate_compat_table(net, &newinfo, &loc_cpu_entry, &tmp); 1518 if (ret != 0) 1519 goto free_newinfo; 1520 1521 ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo, 1522 tmp.num_counters, compat_ptr(tmp.counters)); 1523 if (ret) 1524 goto free_newinfo_untrans; 1525 return 0; 1526 1527 free_newinfo_untrans: 1528 xt_entry_foreach(iter, loc_cpu_entry, newinfo->size) 1529 cleanup_entry(iter, net); 1530 free_newinfo: 1531 xt_free_table_info(newinfo); 1532 return ret; 1533 } 1534 1535 struct compat_ipt_get_entries { 1536 char name[XT_TABLE_MAXNAMELEN]; 1537 compat_uint_t size; 1538 struct compat_ipt_entry entrytable[]; 1539 }; 1540 1541 static int 1542 compat_copy_entries_to_user(unsigned int total_size, struct xt_table *table, 1543 void __user *userptr) 1544 { 1545 struct xt_counters *counters; 1546 const struct xt_table_info *private = table->private; 1547 void __user *pos; 1548 unsigned int size; 1549 int ret = 0; 1550 unsigned int i = 0; 1551 struct ipt_entry *iter; 1552 1553 counters = alloc_counters(table); 1554 if (IS_ERR(counters)) 1555 return PTR_ERR(counters); 1556 1557 pos = userptr; 1558 size = total_size; 1559 xt_entry_foreach(iter, private->entries, total_size) { 1560 ret = compat_copy_entry_to_user(iter, &pos, 1561 &size, counters, i++); 1562 if (ret != 0) 1563 break; 1564 } 1565 1566 vfree(counters); 1567 return ret; 1568 } 1569 1570 static int 1571 compat_get_entries(struct net *net, struct compat_ipt_get_entries __user *uptr, 1572 int *len) 1573 { 1574 int ret; 1575 struct compat_ipt_get_entries get; 1576 struct xt_table *t; 1577 1578 if (*len < sizeof(get)) 1579 return -EINVAL; 1580 1581 if (copy_from_user(&get, uptr, sizeof(get)) != 0) 1582 return -EFAULT; 1583 1584 if (*len != sizeof(struct compat_ipt_get_entries) + get.size) 1585 return -EINVAL; 1586 1587 get.name[sizeof(get.name) - 1] = '\0'; 1588 1589 xt_compat_lock(AF_INET); 1590 t = xt_find_table_lock(net, AF_INET, get.name); 1591 if (!IS_ERR(t)) { 1592 const struct xt_table_info *private = t->private; 1593 struct xt_table_info info; 1594 ret = compat_table_info(private, &info); 1595 if (!ret && get.size == info.size) 1596 ret = compat_copy_entries_to_user(private->size, 1597 t, uptr->entrytable); 1598 else if (!ret) 1599 ret = -EAGAIN; 1600 1601 xt_compat_flush_offsets(AF_INET); 1602 module_put(t->me); 1603 xt_table_unlock(t); 1604 } else 1605 ret = PTR_ERR(t); 1606 1607 xt_compat_unlock(AF_INET); 1608 return ret; 1609 } 1610 #endif 1611 1612 static int 1613 do_ipt_set_ctl(struct sock *sk, int cmd, sockptr_t arg, unsigned int len) 1614 { 1615 int ret; 1616 1617 if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN)) 1618 return -EPERM; 1619 1620 switch (cmd) { 1621 case IPT_SO_SET_REPLACE: 1622 #ifdef CONFIG_NETFILTER_XTABLES_COMPAT 1623 if (in_compat_syscall()) 1624 ret = compat_do_replace(sock_net(sk), arg, len); 1625 else 1626 #endif 1627 ret = do_replace(sock_net(sk), arg, len); 1628 break; 1629 1630 case IPT_SO_SET_ADD_COUNTERS: 1631 ret = do_add_counters(sock_net(sk), arg, len); 1632 break; 1633 1634 default: 1635 ret = -EINVAL; 1636 } 1637 1638 return ret; 1639 } 1640 1641 static int 1642 do_ipt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len) 1643 { 1644 int ret; 1645 1646 if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN)) 1647 return -EPERM; 1648 1649 switch (cmd) { 1650 case IPT_SO_GET_INFO: 1651 ret = get_info(sock_net(sk), user, len); 1652 break; 1653 1654 case IPT_SO_GET_ENTRIES: 1655 #ifdef CONFIG_NETFILTER_XTABLES_COMPAT 1656 if (in_compat_syscall()) 1657 ret = compat_get_entries(sock_net(sk), user, len); 1658 else 1659 #endif 1660 ret = get_entries(sock_net(sk), user, len); 1661 break; 1662 1663 case IPT_SO_GET_REVISION_MATCH: 1664 case IPT_SO_GET_REVISION_TARGET: { 1665 struct xt_get_revision rev; 1666 int target; 1667 1668 if (*len != sizeof(rev)) { 1669 ret = -EINVAL; 1670 break; 1671 } 1672 if (copy_from_user(&rev, user, sizeof(rev)) != 0) { 1673 ret = -EFAULT; 1674 break; 1675 } 1676 rev.name[sizeof(rev.name)-1] = 0; 1677 1678 if (cmd == IPT_SO_GET_REVISION_TARGET) 1679 target = 1; 1680 else 1681 target = 0; 1682 1683 try_then_request_module(xt_find_revision(AF_INET, rev.name, 1684 rev.revision, 1685 target, &ret), 1686 "ipt_%s", rev.name); 1687 break; 1688 } 1689 1690 default: 1691 ret = -EINVAL; 1692 } 1693 1694 return ret; 1695 } 1696 1697 static void __ipt_unregister_table(struct net *net, struct xt_table *table) 1698 { 1699 struct xt_table_info *private; 1700 void *loc_cpu_entry; 1701 struct module *table_owner = table->me; 1702 struct ipt_entry *iter; 1703 1704 private = xt_unregister_table(table); 1705 1706 /* Decrease module usage counts and free resources */ 1707 loc_cpu_entry = private->entries; 1708 xt_entry_foreach(iter, loc_cpu_entry, private->size) 1709 cleanup_entry(iter, net); 1710 if (private->number > private->initial_entries) 1711 module_put(table_owner); 1712 xt_free_table_info(private); 1713 } 1714 1715 int ipt_register_table(struct net *net, const struct xt_table *table, 1716 const struct ipt_replace *repl, 1717 const struct nf_hook_ops *template_ops) 1718 { 1719 struct nf_hook_ops *ops; 1720 unsigned int num_ops; 1721 int ret, i; 1722 struct xt_table_info *newinfo; 1723 struct xt_table_info bootstrap = {0}; 1724 void *loc_cpu_entry; 1725 struct xt_table *new_table; 1726 1727 newinfo = xt_alloc_table_info(repl->size); 1728 if (!newinfo) 1729 return -ENOMEM; 1730 1731 loc_cpu_entry = newinfo->entries; 1732 memcpy(loc_cpu_entry, repl->entries, repl->size); 1733 1734 ret = translate_table(net, newinfo, loc_cpu_entry, repl); 1735 if (ret != 0) { 1736 xt_free_table_info(newinfo); 1737 return ret; 1738 } 1739 1740 new_table = xt_register_table(net, table, &bootstrap, newinfo); 1741 if (IS_ERR(new_table)) { 1742 struct ipt_entry *iter; 1743 1744 xt_entry_foreach(iter, loc_cpu_entry, newinfo->size) 1745 cleanup_entry(iter, net); 1746 xt_free_table_info(newinfo); 1747 return PTR_ERR(new_table); 1748 } 1749 1750 /* No template? No need to do anything. This is used by 'nat' table, it registers 1751 * with the nat core instead of the netfilter core. 1752 */ 1753 if (!template_ops) 1754 return 0; 1755 1756 num_ops = hweight32(table->valid_hooks); 1757 if (num_ops == 0) { 1758 ret = -EINVAL; 1759 goto out_free; 1760 } 1761 1762 ops = kmemdup(template_ops, sizeof(*ops) * num_ops, GFP_KERNEL); 1763 if (!ops) { 1764 ret = -ENOMEM; 1765 goto out_free; 1766 } 1767 1768 for (i = 0; i < num_ops; i++) 1769 ops[i].priv = new_table; 1770 1771 new_table->ops = ops; 1772 1773 ret = nf_register_net_hooks(net, ops, num_ops); 1774 if (ret != 0) 1775 goto out_free; 1776 1777 return ret; 1778 1779 out_free: 1780 __ipt_unregister_table(net, new_table); 1781 return ret; 1782 } 1783 1784 void ipt_unregister_table_pre_exit(struct net *net, const char *name) 1785 { 1786 struct xt_table *table = xt_find_table(net, NFPROTO_IPV4, name); 1787 1788 if (table) 1789 nf_unregister_net_hooks(net, table->ops, hweight32(table->valid_hooks)); 1790 } 1791 1792 void ipt_unregister_table_exit(struct net *net, const char *name) 1793 { 1794 struct xt_table *table = xt_find_table(net, NFPROTO_IPV4, name); 1795 1796 if (table) 1797 __ipt_unregister_table(net, table); 1798 } 1799 1800 static struct xt_target ipt_builtin_tg[] __read_mostly = { 1801 { 1802 .name = XT_STANDARD_TARGET, 1803 .targetsize = sizeof(int), 1804 .family = NFPROTO_IPV4, 1805 #ifdef CONFIG_NETFILTER_XTABLES_COMPAT 1806 .compatsize = sizeof(compat_int_t), 1807 .compat_from_user = compat_standard_from_user, 1808 .compat_to_user = compat_standard_to_user, 1809 #endif 1810 }, 1811 { 1812 .name = XT_ERROR_TARGET, 1813 .target = ipt_error, 1814 .targetsize = XT_FUNCTION_MAXNAMELEN, 1815 .family = NFPROTO_IPV4, 1816 }, 1817 }; 1818 1819 static struct nf_sockopt_ops ipt_sockopts = { 1820 .pf = PF_INET, 1821 .set_optmin = IPT_BASE_CTL, 1822 .set_optmax = IPT_SO_SET_MAX+1, 1823 .set = do_ipt_set_ctl, 1824 .get_optmin = IPT_BASE_CTL, 1825 .get_optmax = IPT_SO_GET_MAX+1, 1826 .get = do_ipt_get_ctl, 1827 .owner = THIS_MODULE, 1828 }; 1829 1830 static int __net_init ip_tables_net_init(struct net *net) 1831 { 1832 return xt_proto_init(net, NFPROTO_IPV4); 1833 } 1834 1835 static void __net_exit ip_tables_net_exit(struct net *net) 1836 { 1837 xt_proto_fini(net, NFPROTO_IPV4); 1838 } 1839 1840 static struct pernet_operations ip_tables_net_ops = { 1841 .init = ip_tables_net_init, 1842 .exit = ip_tables_net_exit, 1843 }; 1844 1845 static int __init ip_tables_init(void) 1846 { 1847 int ret; 1848 1849 ret = register_pernet_subsys(&ip_tables_net_ops); 1850 if (ret < 0) 1851 goto err1; 1852 1853 /* No one else will be downing sem now, so we won't sleep */ 1854 ret = xt_register_targets(ipt_builtin_tg, ARRAY_SIZE(ipt_builtin_tg)); 1855 if (ret < 0) 1856 goto err2; 1857 1858 /* Register setsockopt */ 1859 ret = nf_register_sockopt(&ipt_sockopts); 1860 if (ret < 0) 1861 goto err4; 1862 1863 return 0; 1864 1865 err4: 1866 xt_unregister_targets(ipt_builtin_tg, ARRAY_SIZE(ipt_builtin_tg)); 1867 err2: 1868 unregister_pernet_subsys(&ip_tables_net_ops); 1869 err1: 1870 return ret; 1871 } 1872 1873 static void __exit ip_tables_fini(void) 1874 { 1875 nf_unregister_sockopt(&ipt_sockopts); 1876 1877 xt_unregister_targets(ipt_builtin_tg, ARRAY_SIZE(ipt_builtin_tg)); 1878 unregister_pernet_subsys(&ip_tables_net_ops); 1879 } 1880 1881 EXPORT_SYMBOL(ipt_register_table); 1882 EXPORT_SYMBOL(ipt_unregister_table_pre_exit); 1883 EXPORT_SYMBOL(ipt_unregister_table_exit); 1884 EXPORT_SYMBOL(ipt_do_table); 1885 module_init(ip_tables_init); 1886 module_exit(ip_tables_fini); 1887