1 /* 2 * Packet matching code. 3 * 4 * Copyright (C) 1999 Paul `Rusty' Russell & Michael J. Neuling 5 * Copyright (C) 2000-2005 Netfilter Core Team <coreteam@netfilter.org> 6 * Copyright (C) 2006-2010 Patrick McHardy <kaber@trash.net> 7 * 8 * This program is free software; you can redistribute it and/or modify 9 * it under the terms of the GNU General Public License version 2 as 10 * published by the Free Software Foundation. 11 */ 12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 13 #include <linux/cache.h> 14 #include <linux/capability.h> 15 #include <linux/skbuff.h> 16 #include <linux/kmod.h> 17 #include <linux/vmalloc.h> 18 #include <linux/netdevice.h> 19 #include <linux/module.h> 20 #include <linux/icmp.h> 21 #include <net/ip.h> 22 #include <net/compat.h> 23 #include <linux/uaccess.h> 24 #include <linux/mutex.h> 25 #include <linux/proc_fs.h> 26 #include <linux/err.h> 27 #include <linux/cpumask.h> 28 29 #include <linux/netfilter/x_tables.h> 30 #include <linux/netfilter_ipv4/ip_tables.h> 31 #include <net/netfilter/nf_log.h> 32 #include "../../netfilter/xt_repldata.h" 33 34 MODULE_LICENSE("GPL"); 35 MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>"); 36 MODULE_DESCRIPTION("IPv4 packet filter"); 37 MODULE_ALIAS("ipt_icmp"); 38 39 void *ipt_alloc_initial_table(const struct xt_table *info) 40 { 41 return xt_alloc_initial_table(ipt, IPT); 42 } 43 EXPORT_SYMBOL_GPL(ipt_alloc_initial_table); 44 45 /* Returns whether matches rule or not. */ 46 /* Performance critical - called for every packet */ 47 static inline bool 48 ip_packet_match(const struct iphdr *ip, 49 const char *indev, 50 const char *outdev, 51 const struct ipt_ip *ipinfo, 52 int isfrag) 53 { 54 unsigned long ret; 55 56 if (NF_INVF(ipinfo, IPT_INV_SRCIP, 57 (ip->saddr & ipinfo->smsk.s_addr) != ipinfo->src.s_addr) || 58 NF_INVF(ipinfo, IPT_INV_DSTIP, 59 (ip->daddr & ipinfo->dmsk.s_addr) != ipinfo->dst.s_addr)) 60 return false; 61 62 ret = ifname_compare_aligned(indev, ipinfo->iniface, ipinfo->iniface_mask); 63 64 if (NF_INVF(ipinfo, IPT_INV_VIA_IN, ret != 0)) 65 return false; 66 67 ret = ifname_compare_aligned(outdev, ipinfo->outiface, ipinfo->outiface_mask); 68 69 if (NF_INVF(ipinfo, IPT_INV_VIA_OUT, ret != 0)) 70 return false; 71 72 /* Check specific protocol */ 73 if (ipinfo->proto && 74 NF_INVF(ipinfo, IPT_INV_PROTO, ip->protocol != ipinfo->proto)) 75 return false; 76 77 /* If we have a fragment rule but the packet is not a fragment 78 * then we return zero */ 79 if (NF_INVF(ipinfo, IPT_INV_FRAG, 80 (ipinfo->flags & IPT_F_FRAG) && !isfrag)) 81 return false; 82 83 return true; 84 } 85 86 static bool 87 ip_checkentry(const struct ipt_ip *ip) 88 { 89 if (ip->flags & ~IPT_F_MASK) 90 return false; 91 if (ip->invflags & ~IPT_INV_MASK) 92 return false; 93 return true; 94 } 95 96 static unsigned int 97 ipt_error(struct sk_buff *skb, const struct xt_action_param *par) 98 { 99 net_info_ratelimited("error: `%s'\n", (const char *)par->targinfo); 100 101 return NF_DROP; 102 } 103 104 /* Performance critical */ 105 static inline struct ipt_entry * 106 get_entry(const void *base, unsigned int offset) 107 { 108 return (struct ipt_entry *)(base + offset); 109 } 110 111 /* All zeroes == unconditional rule. */ 112 /* Mildly perf critical (only if packet tracing is on) */ 113 static inline bool unconditional(const struct ipt_entry *e) 114 { 115 static const struct ipt_ip uncond; 116 117 return e->target_offset == sizeof(struct ipt_entry) && 118 memcmp(&e->ip, &uncond, sizeof(uncond)) == 0; 119 } 120 121 /* for const-correctness */ 122 static inline const struct xt_entry_target * 123 ipt_get_target_c(const struct ipt_entry *e) 124 { 125 return ipt_get_target((struct ipt_entry *)e); 126 } 127 128 #if IS_ENABLED(CONFIG_NETFILTER_XT_TARGET_TRACE) 129 static const char *const hooknames[] = { 130 [NF_INET_PRE_ROUTING] = "PREROUTING", 131 [NF_INET_LOCAL_IN] = "INPUT", 132 [NF_INET_FORWARD] = "FORWARD", 133 [NF_INET_LOCAL_OUT] = "OUTPUT", 134 [NF_INET_POST_ROUTING] = "POSTROUTING", 135 }; 136 137 enum nf_ip_trace_comments { 138 NF_IP_TRACE_COMMENT_RULE, 139 NF_IP_TRACE_COMMENT_RETURN, 140 NF_IP_TRACE_COMMENT_POLICY, 141 }; 142 143 static const char *const comments[] = { 144 [NF_IP_TRACE_COMMENT_RULE] = "rule", 145 [NF_IP_TRACE_COMMENT_RETURN] = "return", 146 [NF_IP_TRACE_COMMENT_POLICY] = "policy", 147 }; 148 149 static const struct nf_loginfo trace_loginfo = { 150 .type = NF_LOG_TYPE_LOG, 151 .u = { 152 .log = { 153 .level = 4, 154 .logflags = NF_LOG_DEFAULT_MASK, 155 }, 156 }, 157 }; 158 159 /* Mildly perf critical (only if packet tracing is on) */ 160 static inline int 161 get_chainname_rulenum(const struct ipt_entry *s, const struct ipt_entry *e, 162 const char *hookname, const char **chainname, 163 const char **comment, unsigned int *rulenum) 164 { 165 const struct xt_standard_target *t = (void *)ipt_get_target_c(s); 166 167 if (strcmp(t->target.u.kernel.target->name, XT_ERROR_TARGET) == 0) { 168 /* Head of user chain: ERROR target with chainname */ 169 *chainname = t->target.data; 170 (*rulenum) = 0; 171 } else if (s == e) { 172 (*rulenum)++; 173 174 if (unconditional(s) && 175 strcmp(t->target.u.kernel.target->name, 176 XT_STANDARD_TARGET) == 0 && 177 t->verdict < 0) { 178 /* Tail of chains: STANDARD target (return/policy) */ 179 *comment = *chainname == hookname 180 ? comments[NF_IP_TRACE_COMMENT_POLICY] 181 : comments[NF_IP_TRACE_COMMENT_RETURN]; 182 } 183 return 1; 184 } else 185 (*rulenum)++; 186 187 return 0; 188 } 189 190 static void trace_packet(struct net *net, 191 const struct sk_buff *skb, 192 unsigned int hook, 193 const struct net_device *in, 194 const struct net_device *out, 195 const char *tablename, 196 const struct xt_table_info *private, 197 const struct ipt_entry *e) 198 { 199 const struct ipt_entry *root; 200 const char *hookname, *chainname, *comment; 201 const struct ipt_entry *iter; 202 unsigned int rulenum = 0; 203 204 root = get_entry(private->entries, private->hook_entry[hook]); 205 206 hookname = chainname = hooknames[hook]; 207 comment = comments[NF_IP_TRACE_COMMENT_RULE]; 208 209 xt_entry_foreach(iter, root, private->size - private->hook_entry[hook]) 210 if (get_chainname_rulenum(iter, e, hookname, 211 &chainname, &comment, &rulenum) != 0) 212 break; 213 214 nf_log_trace(net, AF_INET, hook, skb, in, out, &trace_loginfo, 215 "TRACE: %s:%s:%s:%u ", 216 tablename, chainname, comment, rulenum); 217 } 218 #endif 219 220 static inline 221 struct ipt_entry *ipt_next_entry(const struct ipt_entry *entry) 222 { 223 return (void *)entry + entry->next_offset; 224 } 225 226 /* Returns one of the generic firewall policies, like NF_ACCEPT. */ 227 unsigned int 228 ipt_do_table(struct sk_buff *skb, 229 const struct nf_hook_state *state, 230 struct xt_table *table) 231 { 232 unsigned int hook = state->hook; 233 static const char nulldevname[IFNAMSIZ] __attribute__((aligned(sizeof(long)))); 234 const struct iphdr *ip; 235 /* Initializing verdict to NF_DROP keeps gcc happy. */ 236 unsigned int verdict = NF_DROP; 237 const char *indev, *outdev; 238 const void *table_base; 239 struct ipt_entry *e, **jumpstack; 240 unsigned int stackidx, cpu; 241 const struct xt_table_info *private; 242 struct xt_action_param acpar; 243 unsigned int addend; 244 245 /* Initialization */ 246 stackidx = 0; 247 ip = ip_hdr(skb); 248 indev = state->in ? state->in->name : nulldevname; 249 outdev = state->out ? state->out->name : nulldevname; 250 /* We handle fragments by dealing with the first fragment as 251 * if it was a normal packet. All other fragments are treated 252 * normally, except that they will NEVER match rules that ask 253 * things we don't know, ie. tcp syn flag or ports). If the 254 * rule is also a fragment-specific rule, non-fragments won't 255 * match it. */ 256 acpar.fragoff = ntohs(ip->frag_off) & IP_OFFSET; 257 acpar.thoff = ip_hdrlen(skb); 258 acpar.hotdrop = false; 259 acpar.state = state; 260 261 WARN_ON(!(table->valid_hooks & (1 << hook))); 262 local_bh_disable(); 263 addend = xt_write_recseq_begin(); 264 private = READ_ONCE(table->private); /* Address dependency. */ 265 cpu = smp_processor_id(); 266 table_base = private->entries; 267 jumpstack = (struct ipt_entry **)private->jumpstack[cpu]; 268 269 /* Switch to alternate jumpstack if we're being invoked via TEE. 270 * TEE issues XT_CONTINUE verdict on original skb so we must not 271 * clobber the jumpstack. 272 * 273 * For recursion via REJECT or SYNPROXY the stack will be clobbered 274 * but it is no problem since absolute verdict is issued by these. 275 */ 276 if (static_key_false(&xt_tee_enabled)) 277 jumpstack += private->stacksize * __this_cpu_read(nf_skb_duplicated); 278 279 e = get_entry(table_base, private->hook_entry[hook]); 280 281 do { 282 const struct xt_entry_target *t; 283 const struct xt_entry_match *ematch; 284 struct xt_counters *counter; 285 286 WARN_ON(!e); 287 if (!ip_packet_match(ip, indev, outdev, 288 &e->ip, acpar.fragoff)) { 289 no_match: 290 e = ipt_next_entry(e); 291 continue; 292 } 293 294 xt_ematch_foreach(ematch, e) { 295 acpar.match = ematch->u.kernel.match; 296 acpar.matchinfo = ematch->data; 297 if (!acpar.match->match(skb, &acpar)) 298 goto no_match; 299 } 300 301 counter = xt_get_this_cpu_counter(&e->counters); 302 ADD_COUNTER(*counter, skb->len, 1); 303 304 t = ipt_get_target_c(e); 305 WARN_ON(!t->u.kernel.target); 306 307 #if IS_ENABLED(CONFIG_NETFILTER_XT_TARGET_TRACE) 308 /* The packet is traced: log it */ 309 if (unlikely(skb->nf_trace)) 310 trace_packet(state->net, skb, hook, state->in, 311 state->out, table->name, private, e); 312 #endif 313 /* Standard target? */ 314 if (!t->u.kernel.target->target) { 315 int v; 316 317 v = ((struct xt_standard_target *)t)->verdict; 318 if (v < 0) { 319 /* Pop from stack? */ 320 if (v != XT_RETURN) { 321 verdict = (unsigned int)(-v) - 1; 322 break; 323 } 324 if (stackidx == 0) { 325 e = get_entry(table_base, 326 private->underflow[hook]); 327 } else { 328 e = jumpstack[--stackidx]; 329 e = ipt_next_entry(e); 330 } 331 continue; 332 } 333 if (table_base + v != ipt_next_entry(e) && 334 !(e->ip.flags & IPT_F_GOTO)) { 335 if (unlikely(stackidx >= private->stacksize)) { 336 verdict = NF_DROP; 337 break; 338 } 339 jumpstack[stackidx++] = e; 340 } 341 342 e = get_entry(table_base, v); 343 continue; 344 } 345 346 acpar.target = t->u.kernel.target; 347 acpar.targinfo = t->data; 348 349 verdict = t->u.kernel.target->target(skb, &acpar); 350 if (verdict == XT_CONTINUE) { 351 /* Target might have changed stuff. */ 352 ip = ip_hdr(skb); 353 e = ipt_next_entry(e); 354 } else { 355 /* Verdict */ 356 break; 357 } 358 } while (!acpar.hotdrop); 359 360 xt_write_recseq_end(addend); 361 local_bh_enable(); 362 363 if (acpar.hotdrop) 364 return NF_DROP; 365 else return verdict; 366 } 367 368 /* Figures out from what hook each rule can be called: returns 0 if 369 there are loops. Puts hook bitmask in comefrom. */ 370 static int 371 mark_source_chains(const struct xt_table_info *newinfo, 372 unsigned int valid_hooks, void *entry0, 373 unsigned int *offsets) 374 { 375 unsigned int hook; 376 377 /* No recursion; use packet counter to save back ptrs (reset 378 to 0 as we leave), and comefrom to save source hook bitmask */ 379 for (hook = 0; hook < NF_INET_NUMHOOKS; hook++) { 380 unsigned int pos = newinfo->hook_entry[hook]; 381 struct ipt_entry *e = entry0 + pos; 382 383 if (!(valid_hooks & (1 << hook))) 384 continue; 385 386 /* Set initial back pointer. */ 387 e->counters.pcnt = pos; 388 389 for (;;) { 390 const struct xt_standard_target *t 391 = (void *)ipt_get_target_c(e); 392 int visited = e->comefrom & (1 << hook); 393 394 if (e->comefrom & (1 << NF_INET_NUMHOOKS)) 395 return 0; 396 397 e->comefrom |= ((1 << hook) | (1 << NF_INET_NUMHOOKS)); 398 399 /* Unconditional return/END. */ 400 if ((unconditional(e) && 401 (strcmp(t->target.u.user.name, 402 XT_STANDARD_TARGET) == 0) && 403 t->verdict < 0) || visited) { 404 unsigned int oldpos, size; 405 406 /* Return: backtrack through the last 407 big jump. */ 408 do { 409 e->comefrom ^= (1<<NF_INET_NUMHOOKS); 410 oldpos = pos; 411 pos = e->counters.pcnt; 412 e->counters.pcnt = 0; 413 414 /* We're at the start. */ 415 if (pos == oldpos) 416 goto next; 417 418 e = entry0 + pos; 419 } while (oldpos == pos + e->next_offset); 420 421 /* Move along one */ 422 size = e->next_offset; 423 e = entry0 + pos + size; 424 if (pos + size >= newinfo->size) 425 return 0; 426 e->counters.pcnt = pos; 427 pos += size; 428 } else { 429 int newpos = t->verdict; 430 431 if (strcmp(t->target.u.user.name, 432 XT_STANDARD_TARGET) == 0 && 433 newpos >= 0) { 434 /* This a jump; chase it. */ 435 if (!xt_find_jump_offset(offsets, newpos, 436 newinfo->number)) 437 return 0; 438 } else { 439 /* ... this is a fallthru */ 440 newpos = pos + e->next_offset; 441 if (newpos >= newinfo->size) 442 return 0; 443 } 444 e = entry0 + newpos; 445 e->counters.pcnt = pos; 446 pos = newpos; 447 } 448 } 449 next: ; 450 } 451 return 1; 452 } 453 454 static void cleanup_match(struct xt_entry_match *m, struct net *net) 455 { 456 struct xt_mtdtor_param par; 457 458 par.net = net; 459 par.match = m->u.kernel.match; 460 par.matchinfo = m->data; 461 par.family = NFPROTO_IPV4; 462 if (par.match->destroy != NULL) 463 par.match->destroy(&par); 464 module_put(par.match->me); 465 } 466 467 static int 468 check_match(struct xt_entry_match *m, struct xt_mtchk_param *par) 469 { 470 const struct ipt_ip *ip = par->entryinfo; 471 472 par->match = m->u.kernel.match; 473 par->matchinfo = m->data; 474 475 return xt_check_match(par, m->u.match_size - sizeof(*m), 476 ip->proto, ip->invflags & IPT_INV_PROTO); 477 } 478 479 static int 480 find_check_match(struct xt_entry_match *m, struct xt_mtchk_param *par) 481 { 482 struct xt_match *match; 483 int ret; 484 485 match = xt_request_find_match(NFPROTO_IPV4, m->u.user.name, 486 m->u.user.revision); 487 if (IS_ERR(match)) 488 return PTR_ERR(match); 489 m->u.kernel.match = match; 490 491 ret = check_match(m, par); 492 if (ret) 493 goto err; 494 495 return 0; 496 err: 497 module_put(m->u.kernel.match->me); 498 return ret; 499 } 500 501 static int check_target(struct ipt_entry *e, struct net *net, const char *name) 502 { 503 struct xt_entry_target *t = ipt_get_target(e); 504 struct xt_tgchk_param par = { 505 .net = net, 506 .table = name, 507 .entryinfo = e, 508 .target = t->u.kernel.target, 509 .targinfo = t->data, 510 .hook_mask = e->comefrom, 511 .family = NFPROTO_IPV4, 512 }; 513 514 return xt_check_target(&par, t->u.target_size - sizeof(*t), 515 e->ip.proto, e->ip.invflags & IPT_INV_PROTO); 516 } 517 518 static int 519 find_check_entry(struct ipt_entry *e, struct net *net, const char *name, 520 unsigned int size, 521 struct xt_percpu_counter_alloc_state *alloc_state) 522 { 523 struct xt_entry_target *t; 524 struct xt_target *target; 525 int ret; 526 unsigned int j; 527 struct xt_mtchk_param mtpar; 528 struct xt_entry_match *ematch; 529 530 if (!xt_percpu_counter_alloc(alloc_state, &e->counters)) 531 return -ENOMEM; 532 533 j = 0; 534 memset(&mtpar, 0, sizeof(mtpar)); 535 mtpar.net = net; 536 mtpar.table = name; 537 mtpar.entryinfo = &e->ip; 538 mtpar.hook_mask = e->comefrom; 539 mtpar.family = NFPROTO_IPV4; 540 xt_ematch_foreach(ematch, e) { 541 ret = find_check_match(ematch, &mtpar); 542 if (ret != 0) 543 goto cleanup_matches; 544 ++j; 545 } 546 547 t = ipt_get_target(e); 548 target = xt_request_find_target(NFPROTO_IPV4, t->u.user.name, 549 t->u.user.revision); 550 if (IS_ERR(target)) { 551 ret = PTR_ERR(target); 552 goto cleanup_matches; 553 } 554 t->u.kernel.target = target; 555 556 ret = check_target(e, net, name); 557 if (ret) 558 goto err; 559 560 return 0; 561 err: 562 module_put(t->u.kernel.target->me); 563 cleanup_matches: 564 xt_ematch_foreach(ematch, e) { 565 if (j-- == 0) 566 break; 567 cleanup_match(ematch, net); 568 } 569 570 xt_percpu_counter_free(&e->counters); 571 572 return ret; 573 } 574 575 static bool check_underflow(const struct ipt_entry *e) 576 { 577 const struct xt_entry_target *t; 578 unsigned int verdict; 579 580 if (!unconditional(e)) 581 return false; 582 t = ipt_get_target_c(e); 583 if (strcmp(t->u.user.name, XT_STANDARD_TARGET) != 0) 584 return false; 585 verdict = ((struct xt_standard_target *)t)->verdict; 586 verdict = -verdict - 1; 587 return verdict == NF_DROP || verdict == NF_ACCEPT; 588 } 589 590 static int 591 check_entry_size_and_hooks(struct ipt_entry *e, 592 struct xt_table_info *newinfo, 593 const unsigned char *base, 594 const unsigned char *limit, 595 const unsigned int *hook_entries, 596 const unsigned int *underflows, 597 unsigned int valid_hooks) 598 { 599 unsigned int h; 600 int err; 601 602 if ((unsigned long)e % __alignof__(struct ipt_entry) != 0 || 603 (unsigned char *)e + sizeof(struct ipt_entry) >= limit || 604 (unsigned char *)e + e->next_offset > limit) 605 return -EINVAL; 606 607 if (e->next_offset 608 < sizeof(struct ipt_entry) + sizeof(struct xt_entry_target)) 609 return -EINVAL; 610 611 if (!ip_checkentry(&e->ip)) 612 return -EINVAL; 613 614 err = xt_check_entry_offsets(e, e->elems, e->target_offset, 615 e->next_offset); 616 if (err) 617 return err; 618 619 /* Check hooks & underflows */ 620 for (h = 0; h < NF_INET_NUMHOOKS; h++) { 621 if (!(valid_hooks & (1 << h))) 622 continue; 623 if ((unsigned char *)e - base == hook_entries[h]) 624 newinfo->hook_entry[h] = hook_entries[h]; 625 if ((unsigned char *)e - base == underflows[h]) { 626 if (!check_underflow(e)) 627 return -EINVAL; 628 629 newinfo->underflow[h] = underflows[h]; 630 } 631 } 632 633 /* Clear counters and comefrom */ 634 e->counters = ((struct xt_counters) { 0, 0 }); 635 e->comefrom = 0; 636 return 0; 637 } 638 639 static void 640 cleanup_entry(struct ipt_entry *e, struct net *net) 641 { 642 struct xt_tgdtor_param par; 643 struct xt_entry_target *t; 644 struct xt_entry_match *ematch; 645 646 /* Cleanup all matches */ 647 xt_ematch_foreach(ematch, e) 648 cleanup_match(ematch, net); 649 t = ipt_get_target(e); 650 651 par.net = net; 652 par.target = t->u.kernel.target; 653 par.targinfo = t->data; 654 par.family = NFPROTO_IPV4; 655 if (par.target->destroy != NULL) 656 par.target->destroy(&par); 657 module_put(par.target->me); 658 xt_percpu_counter_free(&e->counters); 659 } 660 661 /* Checks and translates the user-supplied table segment (held in 662 newinfo) */ 663 static int 664 translate_table(struct net *net, struct xt_table_info *newinfo, void *entry0, 665 const struct ipt_replace *repl) 666 { 667 struct xt_percpu_counter_alloc_state alloc_state = { 0 }; 668 struct ipt_entry *iter; 669 unsigned int *offsets; 670 unsigned int i; 671 int ret = 0; 672 673 newinfo->size = repl->size; 674 newinfo->number = repl->num_entries; 675 676 /* Init all hooks to impossible value. */ 677 for (i = 0; i < NF_INET_NUMHOOKS; i++) { 678 newinfo->hook_entry[i] = 0xFFFFFFFF; 679 newinfo->underflow[i] = 0xFFFFFFFF; 680 } 681 682 offsets = xt_alloc_entry_offsets(newinfo->number); 683 if (!offsets) 684 return -ENOMEM; 685 i = 0; 686 /* Walk through entries, checking offsets. */ 687 xt_entry_foreach(iter, entry0, newinfo->size) { 688 ret = check_entry_size_and_hooks(iter, newinfo, entry0, 689 entry0 + repl->size, 690 repl->hook_entry, 691 repl->underflow, 692 repl->valid_hooks); 693 if (ret != 0) 694 goto out_free; 695 if (i < repl->num_entries) 696 offsets[i] = (void *)iter - entry0; 697 ++i; 698 if (strcmp(ipt_get_target(iter)->u.user.name, 699 XT_ERROR_TARGET) == 0) 700 ++newinfo->stacksize; 701 } 702 703 ret = -EINVAL; 704 if (i != repl->num_entries) 705 goto out_free; 706 707 ret = xt_check_table_hooks(newinfo, repl->valid_hooks); 708 if (ret) 709 goto out_free; 710 711 if (!mark_source_chains(newinfo, repl->valid_hooks, entry0, offsets)) { 712 ret = -ELOOP; 713 goto out_free; 714 } 715 kvfree(offsets); 716 717 /* Finally, each sanity check must pass */ 718 i = 0; 719 xt_entry_foreach(iter, entry0, newinfo->size) { 720 ret = find_check_entry(iter, net, repl->name, repl->size, 721 &alloc_state); 722 if (ret != 0) 723 break; 724 ++i; 725 } 726 727 if (ret != 0) { 728 xt_entry_foreach(iter, entry0, newinfo->size) { 729 if (i-- == 0) 730 break; 731 cleanup_entry(iter, net); 732 } 733 return ret; 734 } 735 736 return ret; 737 out_free: 738 kvfree(offsets); 739 return ret; 740 } 741 742 static void 743 get_counters(const struct xt_table_info *t, 744 struct xt_counters counters[]) 745 { 746 struct ipt_entry *iter; 747 unsigned int cpu; 748 unsigned int i; 749 750 for_each_possible_cpu(cpu) { 751 seqcount_t *s = &per_cpu(xt_recseq, cpu); 752 753 i = 0; 754 xt_entry_foreach(iter, t->entries, t->size) { 755 struct xt_counters *tmp; 756 u64 bcnt, pcnt; 757 unsigned int start; 758 759 tmp = xt_get_per_cpu_counter(&iter->counters, cpu); 760 do { 761 start = read_seqcount_begin(s); 762 bcnt = tmp->bcnt; 763 pcnt = tmp->pcnt; 764 } while (read_seqcount_retry(s, start)); 765 766 ADD_COUNTER(counters[i], bcnt, pcnt); 767 ++i; /* macro does multi eval of i */ 768 cond_resched(); 769 } 770 } 771 } 772 773 static void get_old_counters(const struct xt_table_info *t, 774 struct xt_counters counters[]) 775 { 776 struct ipt_entry *iter; 777 unsigned int cpu, i; 778 779 for_each_possible_cpu(cpu) { 780 i = 0; 781 xt_entry_foreach(iter, t->entries, t->size) { 782 const struct xt_counters *tmp; 783 784 tmp = xt_get_per_cpu_counter(&iter->counters, cpu); 785 ADD_COUNTER(counters[i], tmp->bcnt, tmp->pcnt); 786 ++i; /* macro does multi eval of i */ 787 } 788 789 cond_resched(); 790 } 791 } 792 793 static struct xt_counters *alloc_counters(const struct xt_table *table) 794 { 795 unsigned int countersize; 796 struct xt_counters *counters; 797 const struct xt_table_info *private = table->private; 798 799 /* We need atomic snapshot of counters: rest doesn't change 800 (other than comefrom, which userspace doesn't care 801 about). */ 802 countersize = sizeof(struct xt_counters) * private->number; 803 counters = vzalloc(countersize); 804 805 if (counters == NULL) 806 return ERR_PTR(-ENOMEM); 807 808 get_counters(private, counters); 809 810 return counters; 811 } 812 813 static int 814 copy_entries_to_user(unsigned int total_size, 815 const struct xt_table *table, 816 void __user *userptr) 817 { 818 unsigned int off, num; 819 const struct ipt_entry *e; 820 struct xt_counters *counters; 821 const struct xt_table_info *private = table->private; 822 int ret = 0; 823 const void *loc_cpu_entry; 824 825 counters = alloc_counters(table); 826 if (IS_ERR(counters)) 827 return PTR_ERR(counters); 828 829 loc_cpu_entry = private->entries; 830 831 /* FIXME: use iterator macros --RR */ 832 /* ... then go back and fix counters and names */ 833 for (off = 0, num = 0; off < total_size; off += e->next_offset, num++){ 834 unsigned int i; 835 const struct xt_entry_match *m; 836 const struct xt_entry_target *t; 837 838 e = loc_cpu_entry + off; 839 if (copy_to_user(userptr + off, e, sizeof(*e))) { 840 ret = -EFAULT; 841 goto free_counters; 842 } 843 if (copy_to_user(userptr + off 844 + offsetof(struct ipt_entry, counters), 845 &counters[num], 846 sizeof(counters[num])) != 0) { 847 ret = -EFAULT; 848 goto free_counters; 849 } 850 851 for (i = sizeof(struct ipt_entry); 852 i < e->target_offset; 853 i += m->u.match_size) { 854 m = (void *)e + i; 855 856 if (xt_match_to_user(m, userptr + off + i)) { 857 ret = -EFAULT; 858 goto free_counters; 859 } 860 } 861 862 t = ipt_get_target_c(e); 863 if (xt_target_to_user(t, userptr + off + e->target_offset)) { 864 ret = -EFAULT; 865 goto free_counters; 866 } 867 } 868 869 free_counters: 870 vfree(counters); 871 return ret; 872 } 873 874 #ifdef CONFIG_COMPAT 875 static void compat_standard_from_user(void *dst, const void *src) 876 { 877 int v = *(compat_int_t *)src; 878 879 if (v > 0) 880 v += xt_compat_calc_jump(AF_INET, v); 881 memcpy(dst, &v, sizeof(v)); 882 } 883 884 static int compat_standard_to_user(void __user *dst, const void *src) 885 { 886 compat_int_t cv = *(int *)src; 887 888 if (cv > 0) 889 cv -= xt_compat_calc_jump(AF_INET, cv); 890 return copy_to_user(dst, &cv, sizeof(cv)) ? -EFAULT : 0; 891 } 892 893 static int compat_calc_entry(const struct ipt_entry *e, 894 const struct xt_table_info *info, 895 const void *base, struct xt_table_info *newinfo) 896 { 897 const struct xt_entry_match *ematch; 898 const struct xt_entry_target *t; 899 unsigned int entry_offset; 900 int off, i, ret; 901 902 off = sizeof(struct ipt_entry) - sizeof(struct compat_ipt_entry); 903 entry_offset = (void *)e - base; 904 xt_ematch_foreach(ematch, e) 905 off += xt_compat_match_offset(ematch->u.kernel.match); 906 t = ipt_get_target_c(e); 907 off += xt_compat_target_offset(t->u.kernel.target); 908 newinfo->size -= off; 909 ret = xt_compat_add_offset(AF_INET, entry_offset, off); 910 if (ret) 911 return ret; 912 913 for (i = 0; i < NF_INET_NUMHOOKS; i++) { 914 if (info->hook_entry[i] && 915 (e < (struct ipt_entry *)(base + info->hook_entry[i]))) 916 newinfo->hook_entry[i] -= off; 917 if (info->underflow[i] && 918 (e < (struct ipt_entry *)(base + info->underflow[i]))) 919 newinfo->underflow[i] -= off; 920 } 921 return 0; 922 } 923 924 static int compat_table_info(const struct xt_table_info *info, 925 struct xt_table_info *newinfo) 926 { 927 struct ipt_entry *iter; 928 const void *loc_cpu_entry; 929 int ret; 930 931 if (!newinfo || !info) 932 return -EINVAL; 933 934 /* we dont care about newinfo->entries */ 935 memcpy(newinfo, info, offsetof(struct xt_table_info, entries)); 936 newinfo->initial_entries = 0; 937 loc_cpu_entry = info->entries; 938 ret = xt_compat_init_offsets(AF_INET, info->number); 939 if (ret) 940 return ret; 941 xt_entry_foreach(iter, loc_cpu_entry, info->size) { 942 ret = compat_calc_entry(iter, info, loc_cpu_entry, newinfo); 943 if (ret != 0) 944 return ret; 945 } 946 return 0; 947 } 948 #endif 949 950 static int get_info(struct net *net, void __user *user, 951 const int *len, int compat) 952 { 953 char name[XT_TABLE_MAXNAMELEN]; 954 struct xt_table *t; 955 int ret; 956 957 if (*len != sizeof(struct ipt_getinfo)) 958 return -EINVAL; 959 960 if (copy_from_user(name, user, sizeof(name)) != 0) 961 return -EFAULT; 962 963 name[XT_TABLE_MAXNAMELEN-1] = '\0'; 964 #ifdef CONFIG_COMPAT 965 if (compat) 966 xt_compat_lock(AF_INET); 967 #endif 968 t = xt_request_find_table_lock(net, AF_INET, name); 969 if (!IS_ERR(t)) { 970 struct ipt_getinfo info; 971 const struct xt_table_info *private = t->private; 972 #ifdef CONFIG_COMPAT 973 struct xt_table_info tmp; 974 975 if (compat) { 976 ret = compat_table_info(private, &tmp); 977 xt_compat_flush_offsets(AF_INET); 978 private = &tmp; 979 } 980 #endif 981 memset(&info, 0, sizeof(info)); 982 info.valid_hooks = t->valid_hooks; 983 memcpy(info.hook_entry, private->hook_entry, 984 sizeof(info.hook_entry)); 985 memcpy(info.underflow, private->underflow, 986 sizeof(info.underflow)); 987 info.num_entries = private->number; 988 info.size = private->size; 989 strcpy(info.name, name); 990 991 if (copy_to_user(user, &info, *len) != 0) 992 ret = -EFAULT; 993 else 994 ret = 0; 995 996 xt_table_unlock(t); 997 module_put(t->me); 998 } else 999 ret = PTR_ERR(t); 1000 #ifdef CONFIG_COMPAT 1001 if (compat) 1002 xt_compat_unlock(AF_INET); 1003 #endif 1004 return ret; 1005 } 1006 1007 static int 1008 get_entries(struct net *net, struct ipt_get_entries __user *uptr, 1009 const int *len) 1010 { 1011 int ret; 1012 struct ipt_get_entries get; 1013 struct xt_table *t; 1014 1015 if (*len < sizeof(get)) 1016 return -EINVAL; 1017 if (copy_from_user(&get, uptr, sizeof(get)) != 0) 1018 return -EFAULT; 1019 if (*len != sizeof(struct ipt_get_entries) + get.size) 1020 return -EINVAL; 1021 get.name[sizeof(get.name) - 1] = '\0'; 1022 1023 t = xt_find_table_lock(net, AF_INET, get.name); 1024 if (!IS_ERR(t)) { 1025 const struct xt_table_info *private = t->private; 1026 if (get.size == private->size) 1027 ret = copy_entries_to_user(private->size, 1028 t, uptr->entrytable); 1029 else 1030 ret = -EAGAIN; 1031 1032 module_put(t->me); 1033 xt_table_unlock(t); 1034 } else 1035 ret = PTR_ERR(t); 1036 1037 return ret; 1038 } 1039 1040 static int 1041 __do_replace(struct net *net, const char *name, unsigned int valid_hooks, 1042 struct xt_table_info *newinfo, unsigned int num_counters, 1043 void __user *counters_ptr) 1044 { 1045 int ret; 1046 struct xt_table *t; 1047 struct xt_table_info *oldinfo; 1048 struct xt_counters *counters; 1049 struct ipt_entry *iter; 1050 1051 ret = 0; 1052 counters = xt_counters_alloc(num_counters); 1053 if (!counters) { 1054 ret = -ENOMEM; 1055 goto out; 1056 } 1057 1058 t = xt_request_find_table_lock(net, AF_INET, name); 1059 if (IS_ERR(t)) { 1060 ret = PTR_ERR(t); 1061 goto free_newinfo_counters_untrans; 1062 } 1063 1064 /* You lied! */ 1065 if (valid_hooks != t->valid_hooks) { 1066 ret = -EINVAL; 1067 goto put_module; 1068 } 1069 1070 oldinfo = xt_replace_table(t, num_counters, newinfo, &ret); 1071 if (!oldinfo) 1072 goto put_module; 1073 1074 /* Update module usage count based on number of rules */ 1075 if ((oldinfo->number > oldinfo->initial_entries) || 1076 (newinfo->number <= oldinfo->initial_entries)) 1077 module_put(t->me); 1078 if ((oldinfo->number > oldinfo->initial_entries) && 1079 (newinfo->number <= oldinfo->initial_entries)) 1080 module_put(t->me); 1081 1082 xt_table_unlock(t); 1083 1084 get_old_counters(oldinfo, counters); 1085 1086 /* Decrease module usage counts and free resource */ 1087 xt_entry_foreach(iter, oldinfo->entries, oldinfo->size) 1088 cleanup_entry(iter, net); 1089 1090 xt_free_table_info(oldinfo); 1091 if (copy_to_user(counters_ptr, counters, 1092 sizeof(struct xt_counters) * num_counters) != 0) { 1093 /* Silent error, can't fail, new table is already in place */ 1094 net_warn_ratelimited("iptables: counters copy to user failed while replacing table\n"); 1095 } 1096 vfree(counters); 1097 return ret; 1098 1099 put_module: 1100 module_put(t->me); 1101 xt_table_unlock(t); 1102 free_newinfo_counters_untrans: 1103 vfree(counters); 1104 out: 1105 return ret; 1106 } 1107 1108 static int 1109 do_replace(struct net *net, const void __user *user, unsigned int len) 1110 { 1111 int ret; 1112 struct ipt_replace tmp; 1113 struct xt_table_info *newinfo; 1114 void *loc_cpu_entry; 1115 struct ipt_entry *iter; 1116 1117 if (copy_from_user(&tmp, user, sizeof(tmp)) != 0) 1118 return -EFAULT; 1119 1120 /* overflow check */ 1121 if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters)) 1122 return -ENOMEM; 1123 if (tmp.num_counters == 0) 1124 return -EINVAL; 1125 1126 tmp.name[sizeof(tmp.name)-1] = 0; 1127 1128 newinfo = xt_alloc_table_info(tmp.size); 1129 if (!newinfo) 1130 return -ENOMEM; 1131 1132 loc_cpu_entry = newinfo->entries; 1133 if (copy_from_user(loc_cpu_entry, user + sizeof(tmp), 1134 tmp.size) != 0) { 1135 ret = -EFAULT; 1136 goto free_newinfo; 1137 } 1138 1139 ret = translate_table(net, newinfo, loc_cpu_entry, &tmp); 1140 if (ret != 0) 1141 goto free_newinfo; 1142 1143 ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo, 1144 tmp.num_counters, tmp.counters); 1145 if (ret) 1146 goto free_newinfo_untrans; 1147 return 0; 1148 1149 free_newinfo_untrans: 1150 xt_entry_foreach(iter, loc_cpu_entry, newinfo->size) 1151 cleanup_entry(iter, net); 1152 free_newinfo: 1153 xt_free_table_info(newinfo); 1154 return ret; 1155 } 1156 1157 static int 1158 do_add_counters(struct net *net, const void __user *user, 1159 unsigned int len, int compat) 1160 { 1161 unsigned int i; 1162 struct xt_counters_info tmp; 1163 struct xt_counters *paddc; 1164 struct xt_table *t; 1165 const struct xt_table_info *private; 1166 int ret = 0; 1167 struct ipt_entry *iter; 1168 unsigned int addend; 1169 1170 paddc = xt_copy_counters_from_user(user, len, &tmp, compat); 1171 if (IS_ERR(paddc)) 1172 return PTR_ERR(paddc); 1173 1174 t = xt_find_table_lock(net, AF_INET, tmp.name); 1175 if (IS_ERR(t)) { 1176 ret = PTR_ERR(t); 1177 goto free; 1178 } 1179 1180 local_bh_disable(); 1181 private = t->private; 1182 if (private->number != tmp.num_counters) { 1183 ret = -EINVAL; 1184 goto unlock_up_free; 1185 } 1186 1187 i = 0; 1188 addend = xt_write_recseq_begin(); 1189 xt_entry_foreach(iter, private->entries, private->size) { 1190 struct xt_counters *tmp; 1191 1192 tmp = xt_get_this_cpu_counter(&iter->counters); 1193 ADD_COUNTER(*tmp, paddc[i].bcnt, paddc[i].pcnt); 1194 ++i; 1195 } 1196 xt_write_recseq_end(addend); 1197 unlock_up_free: 1198 local_bh_enable(); 1199 xt_table_unlock(t); 1200 module_put(t->me); 1201 free: 1202 vfree(paddc); 1203 1204 return ret; 1205 } 1206 1207 #ifdef CONFIG_COMPAT 1208 struct compat_ipt_replace { 1209 char name[XT_TABLE_MAXNAMELEN]; 1210 u32 valid_hooks; 1211 u32 num_entries; 1212 u32 size; 1213 u32 hook_entry[NF_INET_NUMHOOKS]; 1214 u32 underflow[NF_INET_NUMHOOKS]; 1215 u32 num_counters; 1216 compat_uptr_t counters; /* struct xt_counters * */ 1217 struct compat_ipt_entry entries[0]; 1218 }; 1219 1220 static int 1221 compat_copy_entry_to_user(struct ipt_entry *e, void __user **dstptr, 1222 unsigned int *size, struct xt_counters *counters, 1223 unsigned int i) 1224 { 1225 struct xt_entry_target *t; 1226 struct compat_ipt_entry __user *ce; 1227 u_int16_t target_offset, next_offset; 1228 compat_uint_t origsize; 1229 const struct xt_entry_match *ematch; 1230 int ret = 0; 1231 1232 origsize = *size; 1233 ce = *dstptr; 1234 if (copy_to_user(ce, e, sizeof(struct ipt_entry)) != 0 || 1235 copy_to_user(&ce->counters, &counters[i], 1236 sizeof(counters[i])) != 0) 1237 return -EFAULT; 1238 1239 *dstptr += sizeof(struct compat_ipt_entry); 1240 *size -= sizeof(struct ipt_entry) - sizeof(struct compat_ipt_entry); 1241 1242 xt_ematch_foreach(ematch, e) { 1243 ret = xt_compat_match_to_user(ematch, dstptr, size); 1244 if (ret != 0) 1245 return ret; 1246 } 1247 target_offset = e->target_offset - (origsize - *size); 1248 t = ipt_get_target(e); 1249 ret = xt_compat_target_to_user(t, dstptr, size); 1250 if (ret) 1251 return ret; 1252 next_offset = e->next_offset - (origsize - *size); 1253 if (put_user(target_offset, &ce->target_offset) != 0 || 1254 put_user(next_offset, &ce->next_offset) != 0) 1255 return -EFAULT; 1256 return 0; 1257 } 1258 1259 static int 1260 compat_find_calc_match(struct xt_entry_match *m, 1261 const struct ipt_ip *ip, 1262 int *size) 1263 { 1264 struct xt_match *match; 1265 1266 match = xt_request_find_match(NFPROTO_IPV4, m->u.user.name, 1267 m->u.user.revision); 1268 if (IS_ERR(match)) 1269 return PTR_ERR(match); 1270 1271 m->u.kernel.match = match; 1272 *size += xt_compat_match_offset(match); 1273 return 0; 1274 } 1275 1276 static void compat_release_entry(struct compat_ipt_entry *e) 1277 { 1278 struct xt_entry_target *t; 1279 struct xt_entry_match *ematch; 1280 1281 /* Cleanup all matches */ 1282 xt_ematch_foreach(ematch, e) 1283 module_put(ematch->u.kernel.match->me); 1284 t = compat_ipt_get_target(e); 1285 module_put(t->u.kernel.target->me); 1286 } 1287 1288 static int 1289 check_compat_entry_size_and_hooks(struct compat_ipt_entry *e, 1290 struct xt_table_info *newinfo, 1291 unsigned int *size, 1292 const unsigned char *base, 1293 const unsigned char *limit) 1294 { 1295 struct xt_entry_match *ematch; 1296 struct xt_entry_target *t; 1297 struct xt_target *target; 1298 unsigned int entry_offset; 1299 unsigned int j; 1300 int ret, off; 1301 1302 if ((unsigned long)e % __alignof__(struct compat_ipt_entry) != 0 || 1303 (unsigned char *)e + sizeof(struct compat_ipt_entry) >= limit || 1304 (unsigned char *)e + e->next_offset > limit) 1305 return -EINVAL; 1306 1307 if (e->next_offset < sizeof(struct compat_ipt_entry) + 1308 sizeof(struct compat_xt_entry_target)) 1309 return -EINVAL; 1310 1311 if (!ip_checkentry(&e->ip)) 1312 return -EINVAL; 1313 1314 ret = xt_compat_check_entry_offsets(e, e->elems, 1315 e->target_offset, e->next_offset); 1316 if (ret) 1317 return ret; 1318 1319 off = sizeof(struct ipt_entry) - sizeof(struct compat_ipt_entry); 1320 entry_offset = (void *)e - (void *)base; 1321 j = 0; 1322 xt_ematch_foreach(ematch, e) { 1323 ret = compat_find_calc_match(ematch, &e->ip, &off); 1324 if (ret != 0) 1325 goto release_matches; 1326 ++j; 1327 } 1328 1329 t = compat_ipt_get_target(e); 1330 target = xt_request_find_target(NFPROTO_IPV4, t->u.user.name, 1331 t->u.user.revision); 1332 if (IS_ERR(target)) { 1333 ret = PTR_ERR(target); 1334 goto release_matches; 1335 } 1336 t->u.kernel.target = target; 1337 1338 off += xt_compat_target_offset(target); 1339 *size += off; 1340 ret = xt_compat_add_offset(AF_INET, entry_offset, off); 1341 if (ret) 1342 goto out; 1343 1344 return 0; 1345 1346 out: 1347 module_put(t->u.kernel.target->me); 1348 release_matches: 1349 xt_ematch_foreach(ematch, e) { 1350 if (j-- == 0) 1351 break; 1352 module_put(ematch->u.kernel.match->me); 1353 } 1354 return ret; 1355 } 1356 1357 static void 1358 compat_copy_entry_from_user(struct compat_ipt_entry *e, void **dstptr, 1359 unsigned int *size, 1360 struct xt_table_info *newinfo, unsigned char *base) 1361 { 1362 struct xt_entry_target *t; 1363 struct ipt_entry *de; 1364 unsigned int origsize; 1365 int h; 1366 struct xt_entry_match *ematch; 1367 1368 origsize = *size; 1369 de = *dstptr; 1370 memcpy(de, e, sizeof(struct ipt_entry)); 1371 memcpy(&de->counters, &e->counters, sizeof(e->counters)); 1372 1373 *dstptr += sizeof(struct ipt_entry); 1374 *size += sizeof(struct ipt_entry) - sizeof(struct compat_ipt_entry); 1375 1376 xt_ematch_foreach(ematch, e) 1377 xt_compat_match_from_user(ematch, dstptr, size); 1378 1379 de->target_offset = e->target_offset - (origsize - *size); 1380 t = compat_ipt_get_target(e); 1381 xt_compat_target_from_user(t, dstptr, size); 1382 1383 de->next_offset = e->next_offset - (origsize - *size); 1384 1385 for (h = 0; h < NF_INET_NUMHOOKS; h++) { 1386 if ((unsigned char *)de - base < newinfo->hook_entry[h]) 1387 newinfo->hook_entry[h] -= origsize - *size; 1388 if ((unsigned char *)de - base < newinfo->underflow[h]) 1389 newinfo->underflow[h] -= origsize - *size; 1390 } 1391 } 1392 1393 static int 1394 translate_compat_table(struct net *net, 1395 struct xt_table_info **pinfo, 1396 void **pentry0, 1397 const struct compat_ipt_replace *compatr) 1398 { 1399 unsigned int i, j; 1400 struct xt_table_info *newinfo, *info; 1401 void *pos, *entry0, *entry1; 1402 struct compat_ipt_entry *iter0; 1403 struct ipt_replace repl; 1404 unsigned int size; 1405 int ret; 1406 1407 info = *pinfo; 1408 entry0 = *pentry0; 1409 size = compatr->size; 1410 info->number = compatr->num_entries; 1411 1412 j = 0; 1413 xt_compat_lock(AF_INET); 1414 ret = xt_compat_init_offsets(AF_INET, compatr->num_entries); 1415 if (ret) 1416 goto out_unlock; 1417 /* Walk through entries, checking offsets. */ 1418 xt_entry_foreach(iter0, entry0, compatr->size) { 1419 ret = check_compat_entry_size_and_hooks(iter0, info, &size, 1420 entry0, 1421 entry0 + compatr->size); 1422 if (ret != 0) 1423 goto out_unlock; 1424 ++j; 1425 } 1426 1427 ret = -EINVAL; 1428 if (j != compatr->num_entries) 1429 goto out_unlock; 1430 1431 ret = -ENOMEM; 1432 newinfo = xt_alloc_table_info(size); 1433 if (!newinfo) 1434 goto out_unlock; 1435 1436 newinfo->number = compatr->num_entries; 1437 for (i = 0; i < NF_INET_NUMHOOKS; i++) { 1438 newinfo->hook_entry[i] = compatr->hook_entry[i]; 1439 newinfo->underflow[i] = compatr->underflow[i]; 1440 } 1441 entry1 = newinfo->entries; 1442 pos = entry1; 1443 size = compatr->size; 1444 xt_entry_foreach(iter0, entry0, compatr->size) 1445 compat_copy_entry_from_user(iter0, &pos, &size, 1446 newinfo, entry1); 1447 1448 /* all module references in entry0 are now gone. 1449 * entry1/newinfo contains a 64bit ruleset that looks exactly as 1450 * generated by 64bit userspace. 1451 * 1452 * Call standard translate_table() to validate all hook_entrys, 1453 * underflows, check for loops, etc. 1454 */ 1455 xt_compat_flush_offsets(AF_INET); 1456 xt_compat_unlock(AF_INET); 1457 1458 memcpy(&repl, compatr, sizeof(*compatr)); 1459 1460 for (i = 0; i < NF_INET_NUMHOOKS; i++) { 1461 repl.hook_entry[i] = newinfo->hook_entry[i]; 1462 repl.underflow[i] = newinfo->underflow[i]; 1463 } 1464 1465 repl.num_counters = 0; 1466 repl.counters = NULL; 1467 repl.size = newinfo->size; 1468 ret = translate_table(net, newinfo, entry1, &repl); 1469 if (ret) 1470 goto free_newinfo; 1471 1472 *pinfo = newinfo; 1473 *pentry0 = entry1; 1474 xt_free_table_info(info); 1475 return 0; 1476 1477 free_newinfo: 1478 xt_free_table_info(newinfo); 1479 return ret; 1480 out_unlock: 1481 xt_compat_flush_offsets(AF_INET); 1482 xt_compat_unlock(AF_INET); 1483 xt_entry_foreach(iter0, entry0, compatr->size) { 1484 if (j-- == 0) 1485 break; 1486 compat_release_entry(iter0); 1487 } 1488 return ret; 1489 } 1490 1491 static int 1492 compat_do_replace(struct net *net, void __user *user, unsigned int len) 1493 { 1494 int ret; 1495 struct compat_ipt_replace tmp; 1496 struct xt_table_info *newinfo; 1497 void *loc_cpu_entry; 1498 struct ipt_entry *iter; 1499 1500 if (copy_from_user(&tmp, user, sizeof(tmp)) != 0) 1501 return -EFAULT; 1502 1503 /* overflow check */ 1504 if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters)) 1505 return -ENOMEM; 1506 if (tmp.num_counters == 0) 1507 return -EINVAL; 1508 1509 tmp.name[sizeof(tmp.name)-1] = 0; 1510 1511 newinfo = xt_alloc_table_info(tmp.size); 1512 if (!newinfo) 1513 return -ENOMEM; 1514 1515 loc_cpu_entry = newinfo->entries; 1516 if (copy_from_user(loc_cpu_entry, user + sizeof(tmp), 1517 tmp.size) != 0) { 1518 ret = -EFAULT; 1519 goto free_newinfo; 1520 } 1521 1522 ret = translate_compat_table(net, &newinfo, &loc_cpu_entry, &tmp); 1523 if (ret != 0) 1524 goto free_newinfo; 1525 1526 ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo, 1527 tmp.num_counters, compat_ptr(tmp.counters)); 1528 if (ret) 1529 goto free_newinfo_untrans; 1530 return 0; 1531 1532 free_newinfo_untrans: 1533 xt_entry_foreach(iter, loc_cpu_entry, newinfo->size) 1534 cleanup_entry(iter, net); 1535 free_newinfo: 1536 xt_free_table_info(newinfo); 1537 return ret; 1538 } 1539 1540 static int 1541 compat_do_ipt_set_ctl(struct sock *sk, int cmd, void __user *user, 1542 unsigned int len) 1543 { 1544 int ret; 1545 1546 if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN)) 1547 return -EPERM; 1548 1549 switch (cmd) { 1550 case IPT_SO_SET_REPLACE: 1551 ret = compat_do_replace(sock_net(sk), user, len); 1552 break; 1553 1554 case IPT_SO_SET_ADD_COUNTERS: 1555 ret = do_add_counters(sock_net(sk), user, len, 1); 1556 break; 1557 1558 default: 1559 ret = -EINVAL; 1560 } 1561 1562 return ret; 1563 } 1564 1565 struct compat_ipt_get_entries { 1566 char name[XT_TABLE_MAXNAMELEN]; 1567 compat_uint_t size; 1568 struct compat_ipt_entry entrytable[0]; 1569 }; 1570 1571 static int 1572 compat_copy_entries_to_user(unsigned int total_size, struct xt_table *table, 1573 void __user *userptr) 1574 { 1575 struct xt_counters *counters; 1576 const struct xt_table_info *private = table->private; 1577 void __user *pos; 1578 unsigned int size; 1579 int ret = 0; 1580 unsigned int i = 0; 1581 struct ipt_entry *iter; 1582 1583 counters = alloc_counters(table); 1584 if (IS_ERR(counters)) 1585 return PTR_ERR(counters); 1586 1587 pos = userptr; 1588 size = total_size; 1589 xt_entry_foreach(iter, private->entries, total_size) { 1590 ret = compat_copy_entry_to_user(iter, &pos, 1591 &size, counters, i++); 1592 if (ret != 0) 1593 break; 1594 } 1595 1596 vfree(counters); 1597 return ret; 1598 } 1599 1600 static int 1601 compat_get_entries(struct net *net, struct compat_ipt_get_entries __user *uptr, 1602 int *len) 1603 { 1604 int ret; 1605 struct compat_ipt_get_entries get; 1606 struct xt_table *t; 1607 1608 if (*len < sizeof(get)) 1609 return -EINVAL; 1610 1611 if (copy_from_user(&get, uptr, sizeof(get)) != 0) 1612 return -EFAULT; 1613 1614 if (*len != sizeof(struct compat_ipt_get_entries) + get.size) 1615 return -EINVAL; 1616 1617 get.name[sizeof(get.name) - 1] = '\0'; 1618 1619 xt_compat_lock(AF_INET); 1620 t = xt_find_table_lock(net, AF_INET, get.name); 1621 if (!IS_ERR(t)) { 1622 const struct xt_table_info *private = t->private; 1623 struct xt_table_info info; 1624 ret = compat_table_info(private, &info); 1625 if (!ret && get.size == info.size) 1626 ret = compat_copy_entries_to_user(private->size, 1627 t, uptr->entrytable); 1628 else if (!ret) 1629 ret = -EAGAIN; 1630 1631 xt_compat_flush_offsets(AF_INET); 1632 module_put(t->me); 1633 xt_table_unlock(t); 1634 } else 1635 ret = PTR_ERR(t); 1636 1637 xt_compat_unlock(AF_INET); 1638 return ret; 1639 } 1640 1641 static int do_ipt_get_ctl(struct sock *, int, void __user *, int *); 1642 1643 static int 1644 compat_do_ipt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len) 1645 { 1646 int ret; 1647 1648 if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN)) 1649 return -EPERM; 1650 1651 switch (cmd) { 1652 case IPT_SO_GET_INFO: 1653 ret = get_info(sock_net(sk), user, len, 1); 1654 break; 1655 case IPT_SO_GET_ENTRIES: 1656 ret = compat_get_entries(sock_net(sk), user, len); 1657 break; 1658 default: 1659 ret = do_ipt_get_ctl(sk, cmd, user, len); 1660 } 1661 return ret; 1662 } 1663 #endif 1664 1665 static int 1666 do_ipt_set_ctl(struct sock *sk, int cmd, void __user *user, unsigned int len) 1667 { 1668 int ret; 1669 1670 if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN)) 1671 return -EPERM; 1672 1673 switch (cmd) { 1674 case IPT_SO_SET_REPLACE: 1675 ret = do_replace(sock_net(sk), user, len); 1676 break; 1677 1678 case IPT_SO_SET_ADD_COUNTERS: 1679 ret = do_add_counters(sock_net(sk), user, len, 0); 1680 break; 1681 1682 default: 1683 ret = -EINVAL; 1684 } 1685 1686 return ret; 1687 } 1688 1689 static int 1690 do_ipt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len) 1691 { 1692 int ret; 1693 1694 if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN)) 1695 return -EPERM; 1696 1697 switch (cmd) { 1698 case IPT_SO_GET_INFO: 1699 ret = get_info(sock_net(sk), user, len, 0); 1700 break; 1701 1702 case IPT_SO_GET_ENTRIES: 1703 ret = get_entries(sock_net(sk), user, len); 1704 break; 1705 1706 case IPT_SO_GET_REVISION_MATCH: 1707 case IPT_SO_GET_REVISION_TARGET: { 1708 struct xt_get_revision rev; 1709 int target; 1710 1711 if (*len != sizeof(rev)) { 1712 ret = -EINVAL; 1713 break; 1714 } 1715 if (copy_from_user(&rev, user, sizeof(rev)) != 0) { 1716 ret = -EFAULT; 1717 break; 1718 } 1719 rev.name[sizeof(rev.name)-1] = 0; 1720 1721 if (cmd == IPT_SO_GET_REVISION_TARGET) 1722 target = 1; 1723 else 1724 target = 0; 1725 1726 try_then_request_module(xt_find_revision(AF_INET, rev.name, 1727 rev.revision, 1728 target, &ret), 1729 "ipt_%s", rev.name); 1730 break; 1731 } 1732 1733 default: 1734 ret = -EINVAL; 1735 } 1736 1737 return ret; 1738 } 1739 1740 static void __ipt_unregister_table(struct net *net, struct xt_table *table) 1741 { 1742 struct xt_table_info *private; 1743 void *loc_cpu_entry; 1744 struct module *table_owner = table->me; 1745 struct ipt_entry *iter; 1746 1747 private = xt_unregister_table(table); 1748 1749 /* Decrease module usage counts and free resources */ 1750 loc_cpu_entry = private->entries; 1751 xt_entry_foreach(iter, loc_cpu_entry, private->size) 1752 cleanup_entry(iter, net); 1753 if (private->number > private->initial_entries) 1754 module_put(table_owner); 1755 xt_free_table_info(private); 1756 } 1757 1758 int ipt_register_table(struct net *net, const struct xt_table *table, 1759 const struct ipt_replace *repl, 1760 const struct nf_hook_ops *ops, struct xt_table **res) 1761 { 1762 int ret; 1763 struct xt_table_info *newinfo; 1764 struct xt_table_info bootstrap = {0}; 1765 void *loc_cpu_entry; 1766 struct xt_table *new_table; 1767 1768 newinfo = xt_alloc_table_info(repl->size); 1769 if (!newinfo) 1770 return -ENOMEM; 1771 1772 loc_cpu_entry = newinfo->entries; 1773 memcpy(loc_cpu_entry, repl->entries, repl->size); 1774 1775 ret = translate_table(net, newinfo, loc_cpu_entry, repl); 1776 if (ret != 0) 1777 goto out_free; 1778 1779 new_table = xt_register_table(net, table, &bootstrap, newinfo); 1780 if (IS_ERR(new_table)) { 1781 ret = PTR_ERR(new_table); 1782 goto out_free; 1783 } 1784 1785 /* set res now, will see skbs right after nf_register_net_hooks */ 1786 WRITE_ONCE(*res, new_table); 1787 if (!ops) 1788 return 0; 1789 1790 ret = nf_register_net_hooks(net, ops, hweight32(table->valid_hooks)); 1791 if (ret != 0) { 1792 __ipt_unregister_table(net, new_table); 1793 *res = NULL; 1794 } 1795 1796 return ret; 1797 1798 out_free: 1799 xt_free_table_info(newinfo); 1800 return ret; 1801 } 1802 1803 void ipt_unregister_table(struct net *net, struct xt_table *table, 1804 const struct nf_hook_ops *ops) 1805 { 1806 if (ops) 1807 nf_unregister_net_hooks(net, ops, hweight32(table->valid_hooks)); 1808 __ipt_unregister_table(net, table); 1809 } 1810 1811 /* Returns 1 if the type and code is matched by the range, 0 otherwise */ 1812 static inline bool 1813 icmp_type_code_match(u_int8_t test_type, u_int8_t min_code, u_int8_t max_code, 1814 u_int8_t type, u_int8_t code, 1815 bool invert) 1816 { 1817 return ((test_type == 0xFF) || 1818 (type == test_type && code >= min_code && code <= max_code)) 1819 ^ invert; 1820 } 1821 1822 static bool 1823 icmp_match(const struct sk_buff *skb, struct xt_action_param *par) 1824 { 1825 const struct icmphdr *ic; 1826 struct icmphdr _icmph; 1827 const struct ipt_icmp *icmpinfo = par->matchinfo; 1828 1829 /* Must not be a fragment. */ 1830 if (par->fragoff != 0) 1831 return false; 1832 1833 ic = skb_header_pointer(skb, par->thoff, sizeof(_icmph), &_icmph); 1834 if (ic == NULL) { 1835 /* We've been asked to examine this packet, and we 1836 * can't. Hence, no choice but to drop. 1837 */ 1838 par->hotdrop = true; 1839 return false; 1840 } 1841 1842 return icmp_type_code_match(icmpinfo->type, 1843 icmpinfo->code[0], 1844 icmpinfo->code[1], 1845 ic->type, ic->code, 1846 !!(icmpinfo->invflags&IPT_ICMP_INV)); 1847 } 1848 1849 static int icmp_checkentry(const struct xt_mtchk_param *par) 1850 { 1851 const struct ipt_icmp *icmpinfo = par->matchinfo; 1852 1853 /* Must specify no unknown invflags */ 1854 return (icmpinfo->invflags & ~IPT_ICMP_INV) ? -EINVAL : 0; 1855 } 1856 1857 static struct xt_target ipt_builtin_tg[] __read_mostly = { 1858 { 1859 .name = XT_STANDARD_TARGET, 1860 .targetsize = sizeof(int), 1861 .family = NFPROTO_IPV4, 1862 #ifdef CONFIG_COMPAT 1863 .compatsize = sizeof(compat_int_t), 1864 .compat_from_user = compat_standard_from_user, 1865 .compat_to_user = compat_standard_to_user, 1866 #endif 1867 }, 1868 { 1869 .name = XT_ERROR_TARGET, 1870 .target = ipt_error, 1871 .targetsize = XT_FUNCTION_MAXNAMELEN, 1872 .family = NFPROTO_IPV4, 1873 }, 1874 }; 1875 1876 static struct nf_sockopt_ops ipt_sockopts = { 1877 .pf = PF_INET, 1878 .set_optmin = IPT_BASE_CTL, 1879 .set_optmax = IPT_SO_SET_MAX+1, 1880 .set = do_ipt_set_ctl, 1881 #ifdef CONFIG_COMPAT 1882 .compat_set = compat_do_ipt_set_ctl, 1883 #endif 1884 .get_optmin = IPT_BASE_CTL, 1885 .get_optmax = IPT_SO_GET_MAX+1, 1886 .get = do_ipt_get_ctl, 1887 #ifdef CONFIG_COMPAT 1888 .compat_get = compat_do_ipt_get_ctl, 1889 #endif 1890 .owner = THIS_MODULE, 1891 }; 1892 1893 static struct xt_match ipt_builtin_mt[] __read_mostly = { 1894 { 1895 .name = "icmp", 1896 .match = icmp_match, 1897 .matchsize = sizeof(struct ipt_icmp), 1898 .checkentry = icmp_checkentry, 1899 .proto = IPPROTO_ICMP, 1900 .family = NFPROTO_IPV4, 1901 .me = THIS_MODULE, 1902 }, 1903 }; 1904 1905 static int __net_init ip_tables_net_init(struct net *net) 1906 { 1907 return xt_proto_init(net, NFPROTO_IPV4); 1908 } 1909 1910 static void __net_exit ip_tables_net_exit(struct net *net) 1911 { 1912 xt_proto_fini(net, NFPROTO_IPV4); 1913 } 1914 1915 static struct pernet_operations ip_tables_net_ops = { 1916 .init = ip_tables_net_init, 1917 .exit = ip_tables_net_exit, 1918 }; 1919 1920 static int __init ip_tables_init(void) 1921 { 1922 int ret; 1923 1924 ret = register_pernet_subsys(&ip_tables_net_ops); 1925 if (ret < 0) 1926 goto err1; 1927 1928 /* No one else will be downing sem now, so we won't sleep */ 1929 ret = xt_register_targets(ipt_builtin_tg, ARRAY_SIZE(ipt_builtin_tg)); 1930 if (ret < 0) 1931 goto err2; 1932 ret = xt_register_matches(ipt_builtin_mt, ARRAY_SIZE(ipt_builtin_mt)); 1933 if (ret < 0) 1934 goto err4; 1935 1936 /* Register setsockopt */ 1937 ret = nf_register_sockopt(&ipt_sockopts); 1938 if (ret < 0) 1939 goto err5; 1940 1941 return 0; 1942 1943 err5: 1944 xt_unregister_matches(ipt_builtin_mt, ARRAY_SIZE(ipt_builtin_mt)); 1945 err4: 1946 xt_unregister_targets(ipt_builtin_tg, ARRAY_SIZE(ipt_builtin_tg)); 1947 err2: 1948 unregister_pernet_subsys(&ip_tables_net_ops); 1949 err1: 1950 return ret; 1951 } 1952 1953 static void __exit ip_tables_fini(void) 1954 { 1955 nf_unregister_sockopt(&ipt_sockopts); 1956 1957 xt_unregister_matches(ipt_builtin_mt, ARRAY_SIZE(ipt_builtin_mt)); 1958 xt_unregister_targets(ipt_builtin_tg, ARRAY_SIZE(ipt_builtin_tg)); 1959 unregister_pernet_subsys(&ip_tables_net_ops); 1960 } 1961 1962 EXPORT_SYMBOL(ipt_register_table); 1963 EXPORT_SYMBOL(ipt_unregister_table); 1964 EXPORT_SYMBOL(ipt_do_table); 1965 module_init(ip_tables_init); 1966 module_exit(ip_tables_fini); 1967