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