net/ipv4/netfilter/ip_tables.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Packet matching code.
   4  *
   5  * Copyright (C) 1999 Paul `Rusty' Russell & Michael J. Neuling
   6  * Copyright (C) 2000-2005 Netfilter Core Team <[email protected]>
   7  * Copyright (C) 2006-2010 Patrick McHardy <[email protected]>
   8  */
   9 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  10 #include <linux/cache.h>
  11 #include <linux/capability.h>
  12 #include <linux/skbuff.h>
  13 #include <linux/kmod.h>
  14 #include <linux/vmalloc.h>
  15 #include <linux/netdevice.h>
  16 #include <linux/module.h>
  17 #include <linux/icmp.h>
  18 #include <net/ip.h>
  19 #include <net/compat.h>
  20 #include <linux/uaccess.h>
  21 #include <linux/mutex.h>
  22 #include <linux/proc_fs.h>
  23 #include <linux/err.h>
  24 #include <linux/cpumask.h>
  25
  26 #include <linux/netfilter/x_tables.h>
  27 #include <linux/netfilter_ipv4/ip_tables.h>
  28 #include <net/netfilter/nf_log.h>
  29 #include "../../netfilter/xt_repldata.h"
  30
  31 MODULE_LICENSE("GPL");
  32 MODULE_AUTHOR("Netfilter Core Team <[email protected]>");
  33 MODULE_DESCRIPTION("IPv4 packet filter");
  34 MODULE_ALIAS("ipt_icmp");
  35
  36 void *ipt_alloc_initial_table(const struct xt_table *info)
  37 {
  38         return xt_alloc_initial_table(ipt, IPT);
  39 }
  40 EXPORT_SYMBOL_GPL(ipt_alloc_initial_table);
  41
  42 /* Returns whether matches rule or not. */
  43 /* Performance critical - called for every packet */
  44 static inline bool
  45 ip_packet_match(const struct iphdr *ip,
  46                 const char *indev,
  47                 const char *outdev,
  48                 const struct ipt_ip *ipinfo,
  49                 int isfrag)
  50 {
  51         unsigned long ret;
  52
  53         if (NF_INVF(ipinfo, IPT_INV_SRCIP,
  54                     (ip->saddr & ipinfo->smsk.s_addr) != ipinfo->src.s_addr) ||
  55             NF_INVF(ipinfo, IPT_INV_DSTIP,
  56                     (ip->daddr & ipinfo->dmsk.s_addr) != ipinfo->dst.s_addr))
  57                 return false;
  58
  59         ret = ifname_compare_aligned(indev, ipinfo->iniface, ipinfo->iniface_mask);
  60
  61         if (NF_INVF(ipinfo, IPT_INV_VIA_IN, ret != 0))
  62                 return false;
  63
  64         ret = ifname_compare_aligned(outdev, ipinfo->outiface, ipinfo->outiface_mask);
  65
  66         if (NF_INVF(ipinfo, IPT_INV_VIA_OUT, ret != 0))
  67                 return false;
  68
  69         /* Check specific protocol */
  70         if (ipinfo->proto &&
  71             NF_INVF(ipinfo, IPT_INV_PROTO, ip->protocol != ipinfo->proto))
  72                 return false;
  73
  74         /* If we have a fragment rule but the packet is not a fragment
  75          * then we return zero */
  76         if (NF_INVF(ipinfo, IPT_INV_FRAG,
  77                     (ipinfo->flags & IPT_F_FRAG) && !isfrag))
  78                 return false;
  79
  80         return true;
  81 }
  82
  83 static bool
  84 ip_checkentry(const struct ipt_ip *ip)
  85 {
  86         if (ip->flags & ~IPT_F_MASK)
  87                 return false;
  88         if (ip->invflags & ~IPT_INV_MASK)
  89                 return false;
  90         return true;
  91 }
  92
  93 static unsigned int
  94 ipt_error(struct sk_buff *skb, const struct xt_action_param *par)
  95 {
  96         net_info_ratelimited("error: `%s'\n", (const char *)par->targinfo);
  97
  98         return NF_DROP;
  99 }
 100
 101 /* Performance critical */
 102 static inline struct ipt_entry *
 103 get_entry(const void *base, unsigned int offset)
 104 {
 105         return (struct ipt_entry *)(base + offset);
 106 }
 107
 108 /* All zeroes == unconditional rule. */
 109 /* Mildly perf critical (only if packet tracing is on) */
 110 static inline bool unconditional(const struct ipt_entry *e)
 111 {
 112         static const struct ipt_ip uncond;
 113
 114         return e->target_offset == sizeof(struct ipt_entry) &&
 115                memcmp(&e->ip, &uncond, sizeof(uncond)) == 0;
 116 }
 117
 118 /* for const-correctness */
 119 static inline const struct xt_entry_target *
 120 ipt_get_target_c(const struct ipt_entry *e)
 121 {
 122         return ipt_get_target((struct ipt_entry *)e);
 123 }
 124
 125 #if IS_ENABLED(CONFIG_NETFILTER_XT_TARGET_TRACE)
 126 static const char *const hooknames[] = {
 127         [NF_INET_PRE_ROUTING]           = "PREROUTING",
 128         [NF_INET_LOCAL_IN]              = "INPUT",
 129         [NF_INET_FORWARD]               = "FORWARD",
 130         [NF_INET_LOCAL_OUT]             = "OUTPUT",
 131         [NF_INET_POST_ROUTING]          = "POSTROUTING",
 132 };
 133
 134 enum nf_ip_trace_comments {
 135         NF_IP_TRACE_COMMENT_RULE,
 136         NF_IP_TRACE_COMMENT_RETURN,
 137         NF_IP_TRACE_COMMENT_POLICY,
 138 };
 139
 140 static const char *const comments[] = {
 141         [NF_IP_TRACE_COMMENT_RULE]      = "rule",
 142         [NF_IP_TRACE_COMMENT_RETURN]    = "return",
 143         [NF_IP_TRACE_COMMENT_POLICY]    = "policy",
 144 };
 145
 146 static const struct nf_loginfo trace_loginfo = {
 147         .type = NF_LOG_TYPE_LOG,
 148         .u = {
 149                 .log = {
 150                         .level = 4,
 151                         .logflags = NF_LOG_DEFAULT_MASK,
 152                 },
 153         },
 154 };
 155
 156 /* Mildly perf critical (only if packet tracing is on) */
 157 static inline int
 158 get_chainname_rulenum(const struct ipt_entry *s, const struct ipt_entry *e,
 159                       const char *hookname, const char **chainname,
 160                       const char **comment, unsigned int *rulenum)
 161 {
 162         const struct xt_standard_target *t = (void *)ipt_get_target_c(s);
 163
 164         if (strcmp(t->target.u.kernel.target->name, XT_ERROR_TARGET) == 0) {
 165                 /* Head of user chain: ERROR target with chainname */
 166                 *chainname = t->target.data;
 167                 (*rulenum) = 0;
 168         } else if (s == e) {
 169                 (*rulenum)++;
 170
 171                 if (unconditional(s) &&
 172                     strcmp(t->target.u.kernel.target->name,
 173                            XT_STANDARD_TARGET) == 0 &&
 174                    t->verdict < 0) {
 175                         /* Tail of chains: STANDARD target (return/policy) */
 176                         *comment = *chainname == hookname
 177                                 ? comments[NF_IP_TRACE_COMMENT_POLICY]
 178                                 : comments[NF_IP_TRACE_COMMENT_RETURN];
 179                 }
 180                 return 1;
 181         } else
 182                 (*rulenum)++;
 183
 184         return 0;
 185 }
 186
 187 static void trace_packet(struct net *net,
 188                          const struct sk_buff *skb,
 189                          unsigned int hook,
 190                          const struct net_device *in,
 191                          const struct net_device *out,
 192                          const char *tablename,
 193                          const struct xt_table_info *private,
 194                          const struct ipt_entry *e)
 195 {
 196         const struct ipt_entry *root;
 197         const char *hookname, *chainname, *comment;
 198         const struct ipt_entry *iter;
 199         unsigned int rulenum = 0;
 200
 201         root = get_entry(private->entries, private->hook_entry[hook]);
 202
 203         hookname = chainname = hooknames[hook];
 204         comment = comments[NF_IP_TRACE_COMMENT_RULE];
 205
 206         xt_entry_foreach(iter, root, private->size - private->hook_entry[hook])
 207                 if (get_chainname_rulenum(iter, e, hookname,
 208                     &chainname, &comment, &rulenum) != 0)
 209                         break;
 210
 211         nf_log_trace(net, AF_INET, hook, skb, in, out, &trace_loginfo,
 212                      "TRACE: %s:%s:%s:%u ",
 213                      tablename, chainname, comment, rulenum);
 214 }
 215 #endif
 216
 217 static inline
 218 struct ipt_entry *ipt_next_entry(const struct ipt_entry *entry)
 219 {
 220         return (void *)entry + entry->next_offset;
 221 }
 222
 223 /* Returns one of the generic firewall policies, like NF_ACCEPT. */
 224 unsigned int
 225 ipt_do_table(struct sk_buff *skb,
 226              const struct nf_hook_state *state,
 227              struct xt_table *table)
 228 {
 229         unsigned int hook = state->hook;
 230         static const char nulldevname[IFNAMSIZ] __attribute__((aligned(sizeof(long))));
 231         const struct iphdr *ip;
 232         /* Initializing verdict to NF_DROP keeps gcc happy. */
 233         unsigned int verdict = NF_DROP;
 234         const char *indev, *outdev;
 235         const void *table_base;
 236         struct ipt_entry *e, **jumpstack;
 237         unsigned int stackidx, cpu;
 238         const struct xt_table_info *private;
 239         struct xt_action_param acpar;
 240         unsigned int addend;
 241
 242         /* Initialization */
 243         stackidx = 0;
 244         ip = ip_hdr(skb);
 245         indev = state->in ? state->in->name : nulldevname;
 246         outdev = state->out ? state->out->name : nulldevname;
 247         /* We handle fragments by dealing with the first fragment as
 248          * if it was a normal packet.  All other fragments are treated
 249          * normally, except that they will NEVER match rules that ask
 250          * things we don't know, ie. tcp syn flag or ports).  If the
 251          * rule is also a fragment-specific rule, non-fragments won't
 252          * match it. */
 253         acpar.fragoff = ntohs(ip->frag_off) & IP_OFFSET;
 254         acpar.thoff   = ip_hdrlen(skb);
 255         acpar.hotdrop = false;
 256         acpar.state   = state;
 257
 258         WARN_ON(!(table->valid_hooks & (1 << hook)));
 259         local_bh_disable();
 260         addend = xt_write_recseq_begin();
 261         private = READ_ONCE(table->private); /* Address dependency. */
 262         cpu        = smp_processor_id();
 263         table_base = private->entries;
 264         jumpstack  = (struct ipt_entry **)private->jumpstack[cpu];
 265
 266         /* Switch to alternate jumpstack if we're being invoked via TEE.
 267          * TEE issues XT_CONTINUE verdict on original skb so we must not
 268          * clobber the jumpstack.
 269          *
 270          * For recursion via REJECT or SYNPROXY the stack will be clobbered
 271          * but it is no problem since absolute verdict is issued by these.
 272          */
 273         if (static_key_false(&xt_tee_enabled))
 274                 jumpstack += private->stacksize * __this_cpu_read(nf_skb_duplicated);
 275
 276         e = get_entry(table_base, private->hook_entry[hook]);
 277
 278         do {
 279                 const struct xt_entry_target *t;
 280                 const struct xt_entry_match *ematch;
 281                 struct xt_counters *counter;
 282
 283                 WARN_ON(!e);
 284                 if (!ip_packet_match(ip, indev, outdev,
 285                     &e->ip, acpar.fragoff)) {
 286  no_match:
 287                         e = ipt_next_entry(e);
 288                         continue;
 289                 }
 290
 291                 xt_ematch_foreach(ematch, e) {
 292                         acpar.match     = ematch->u.kernel.match;
 293                         acpar.matchinfo = ematch->data;
 294                         if (!acpar.match->match(skb, &acpar))
 295                                 goto no_match;
 296                 }
 297
 298                 counter = xt_get_this_cpu_counter(&e->counters);
 299                 ADD_COUNTER(*counter, skb->len, 1);
 300
 301                 t = ipt_get_target_c(e);
 302                 WARN_ON(!t->u.kernel.target);
 303
 304 #if IS_ENABLED(CONFIG_NETFILTER_XT_TARGET_TRACE)
 305                 /* The packet is traced: log it */
 306                 if (unlikely(skb->nf_trace))
 307                         trace_packet(state->net, skb, hook, state->in,
 308                                      state->out, table->name, private, e);
 309 #endif
 310                 /* Standard target? */
 311                 if (!t->u.kernel.target->target) {
 312                         int v;
 313
 314                         v = ((struct xt_standard_target *)t)->verdict;
 315                         if (v < 0) {
 316                                 /* Pop from stack? */
 317                                 if (v != XT_RETURN) {
 318                                         verdict = (unsigned int)(-v) - 1;
 319                                         break;
 320                                 }
 321                                 if (stackidx == 0) {
 322                                         e = get_entry(table_base,
 323                                             private->underflow[hook]);
 324                                 } else {
 325                                         e = jumpstack[--stackidx];
 326                                         e = ipt_next_entry(e);
 327                                 }
 328                                 continue;
 329                         }
 330                         if (table_base + v != ipt_next_entry(e) &&
 331                             !(e->ip.flags & IPT_F_GOTO)) {
 332                                 if (unlikely(stackidx >= private->stacksize)) {
 333                                         verdict = NF_DROP;
 334                                         break;
 335                                 }
 336                                 jumpstack[stackidx++] = e;
 337                         }
 338
 339                         e = get_entry(table_base, v);
 340                         continue;
 341                 }
 342
 343                 acpar.target   = t->u.kernel.target;
 344                 acpar.targinfo = t->data;
 345
 346                 verdict = t->u.kernel.target->target(skb, &acpar);
 347                 if (verdict == XT_CONTINUE) {
 348                         /* Target might have changed stuff. */
 349                         ip = ip_hdr(skb);
 350                         e = ipt_next_entry(e);
 351                 } else {
 352                         /* Verdict */
 353                         break;
 354                 }
 355         } while (!acpar.hotdrop);
 356
 357         xt_write_recseq_end(addend);
 358         local_bh_enable();
 359
 360         if (acpar.hotdrop)
 361                 return NF_DROP;
 362         else return verdict;
 363 }
 364
 365 /* Figures out from what hook each rule can be called: returns 0 if
 366    there are loops.  Puts hook bitmask in comefrom. */
 367 static int
 368 mark_source_chains(const struct xt_table_info *newinfo,
 369                    unsigned int valid_hooks, void *entry0,
 370                    unsigned int *offsets)
 371 {
 372         unsigned int hook;
 373
 374         /* No recursion; use packet counter to save back ptrs (reset
 375            to 0 as we leave), and comefrom to save source hook bitmask */
 376         for (hook = 0; hook < NF_INET_NUMHOOKS; hook++) {
 377                 unsigned int pos = newinfo->hook_entry[hook];
 378                 struct ipt_entry *e = entry0 + pos;
 379
 380                 if (!(valid_hooks & (1 << hook)))
 381                         continue;
 382
 383                 /* Set initial back pointer. */
 384                 e->counters.pcnt = pos;
 385
 386                 for (;;) {
 387                         const struct xt_standard_target *t
 388                                 = (void *)ipt_get_target_c(e);
 389                         int visited = e->comefrom & (1 << hook);
 390
 391                         if (e->comefrom & (1 << NF_INET_NUMHOOKS))
 392                                 return 0;
 393
 394                         e->comefrom |= ((1 << hook) | (1 << NF_INET_NUMHOOKS));
 395
 396                         /* Unconditional return/END. */
 397                         if ((unconditional(e) &&
 398                              (strcmp(t->target.u.user.name,
 399                                      XT_STANDARD_TARGET) == 0) &&
 400                              t->verdict < 0) || visited) {
 401                                 unsigned int oldpos, size;
 402
 403                                 /* Return: backtrack through the last
 404                                    big jump. */
 405                                 do {
 406                                         e->comefrom ^= (1<<NF_INET_NUMHOOKS);
 407                                         oldpos = pos;
 408                                         pos = e->counters.pcnt;
 409                                         e->counters.pcnt = 0;
 410
 411                                         /* We're at the start. */
 412                                         if (pos == oldpos)
 413                                                 goto next;
 414
 415                                         e = entry0 + pos;
 416                                 } while (oldpos == pos + e->next_offset);
 417
 418                                 /* Move along one */
 419                                 size = e->next_offset;
 420                                 e = entry0 + pos + size;
 421                                 if (pos + size >= newinfo->size)
 422                                         return 0;
 423                                 e->counters.pcnt = pos;
 424                                 pos += size;
 425                         } else {
 426                                 int newpos = t->verdict;
 427
 428                                 if (strcmp(t->target.u.user.name,
 429                                            XT_STANDARD_TARGET) == 0 &&
 430                                     newpos >= 0) {
 431                                         /* This a jump; chase it. */
 432                                         if (!xt_find_jump_offset(offsets, newpos,
 433                                                                  newinfo->number))
 434                                                 return 0;
 435                                 } else {
 436                                         /* ... this is a fallthru */
 437                                         newpos = pos + e->next_offset;
 438                                         if (newpos >= newinfo->size)
 439                                                 return 0;
 440                                 }
 441                                 e = entry0 + newpos;
 442                                 e->counters.pcnt = pos;
 443                                 pos = newpos;
 444                         }
 445                 }
 446 next:           ;
 447         }
 448         return 1;
 449 }
 450
 451 static void cleanup_match(struct xt_entry_match *m, struct net *net)
 452 {
 453         struct xt_mtdtor_param par;
 454
 455         par.net       = net;
 456         par.match     = m->u.kernel.match;
 457         par.matchinfo = m->data;
 458         par.family    = NFPROTO_IPV4;
 459         if (par.match->destroy != NULL)
 460                 par.match->destroy(&par);
 461         module_put(par.match->me);
 462 }
 463
 464 static int
 465 check_match(struct xt_entry_match *m, struct xt_mtchk_param *par)
 466 {
 467         const struct ipt_ip *ip = par->entryinfo;
 468
 469         par->match     = m->u.kernel.match;
 470         par->matchinfo = m->data;
 471
 472         return xt_check_match(par, m->u.match_size - sizeof(*m),
 473                               ip->proto, ip->invflags & IPT_INV_PROTO);
 474 }
 475
 476 static int
 477 find_check_match(struct xt_entry_match *m, struct xt_mtchk_param *par)
 478 {
 479         struct xt_match *match;
 480         int ret;
 481
 482         match = xt_request_find_match(NFPROTO_IPV4, m->u.user.name,
 483                                       m->u.user.revision);
 484         if (IS_ERR(match))
 485                 return PTR_ERR(match);
 486         m->u.kernel.match = match;
 487
 488         ret = check_match(m, par);
 489         if (ret)
 490                 goto err;
 491
 492         return 0;
 493 err:
 494         module_put(m->u.kernel.match->me);
 495         return ret;
 496 }
 497
 498 static int check_target(struct ipt_entry *e, struct net *net, const char *name)
 499 {
 500         struct xt_entry_target *t = ipt_get_target(e);
 501         struct xt_tgchk_param par = {
 502                 .net       = net,
 503                 .table     = name,
 504                 .entryinfo = e,
 505                 .target    = t->u.kernel.target,
 506                 .targinfo  = t->data,
 507                 .hook_mask = e->comefrom,
 508                 .family    = NFPROTO_IPV4,
 509         };
 510
 511         return xt_check_target(&par, t->u.target_size - sizeof(*t),
 512                                e->ip.proto, e->ip.invflags & IPT_INV_PROTO);
 513 }
 514
 515 static int
 516 find_check_entry(struct ipt_entry *e, struct net *net, const char *name,
 517                  unsigned int size,
 518                  struct xt_percpu_counter_alloc_state *alloc_state)
 519 {
 520         struct xt_entry_target *t;
 521         struct xt_target *target;
 522         int ret;
 523         unsigned int j;
 524         struct xt_mtchk_param mtpar;
 525         struct xt_entry_match *ematch;
 526
 527         if (!xt_percpu_counter_alloc(alloc_state, &e->counters))
 528                 return -ENOMEM;
 529
 530         j = 0;
 531         memset(&mtpar, 0, sizeof(mtpar));
 532         mtpar.net       = net;
 533         mtpar.table     = name;
 534         mtpar.entryinfo = &e->ip;
 535         mtpar.hook_mask = e->comefrom;
 536         mtpar.family    = NFPROTO_IPV4;
 537         xt_ematch_foreach(ematch, e) {
 538                 ret = find_check_match(ematch, &mtpar);
 539                 if (ret != 0)
 540                         goto cleanup_matches;
 541                 ++j;
 542         }
 543
 544         t = ipt_get_target(e);
 545         target = xt_request_find_target(NFPROTO_IPV4, t->u.user.name,
 546                                         t->u.user.revision);
 547         if (IS_ERR(target)) {
 548                 ret = PTR_ERR(target);
 549                 goto cleanup_matches;
 550         }
 551         t->u.kernel.target = target;
 552
 553         ret = check_target(e, net, name);
 554         if (ret)
 555                 goto err;
 556
 557         return 0;
 558  err:
 559         module_put(t->u.kernel.target->me);
 560  cleanup_matches:
 561         xt_ematch_foreach(ematch, e) {
 562                 if (j-- == 0)
 563                         break;
 564                 cleanup_match(ematch, net);
 565         }
 566
 567         xt_percpu_counter_free(&e->counters);
 568
 569         return ret;
 570 }
 571
 572 static bool check_underflow(const struct ipt_entry *e)
 573 {
 574         const struct xt_entry_target *t;
 575         unsigned int verdict;
 576
 577         if (!unconditional(e))
 578                 return false;
 579         t = ipt_get_target_c(e);
 580         if (strcmp(t->u.user.name, XT_STANDARD_TARGET) != 0)
 581                 return false;
 582         verdict = ((struct xt_standard_target *)t)->verdict;
 583         verdict = -verdict - 1;
 584         return verdict == NF_DROP || verdict == NF_ACCEPT;
 585 }
 586
 587 static int
 588 check_entry_size_and_hooks(struct ipt_entry *e,
 589                            struct xt_table_info *newinfo,
 590                            const unsigned char *base,
 591                            const unsigned char *limit,
 592                            const unsigned int *hook_entries,
 593                            const unsigned int *underflows,
 594                            unsigned int valid_hooks)
 595 {
 596         unsigned int h;
 597         int err;
 598
 599         if ((unsigned long)e % __alignof__(struct ipt_entry) != 0 ||
 600             (unsigned char *)e + sizeof(struct ipt_entry) >= limit ||
 601             (unsigned char *)e + e->next_offset > limit)
 602                 return -EINVAL;
 603
 604         if (e->next_offset
 605             < sizeof(struct ipt_entry) + sizeof(struct xt_entry_target))
 606                 return -EINVAL;
 607
 608         if (!ip_checkentry(&e->ip))
 609                 return -EINVAL;
 610
 611         err = xt_check_entry_offsets(e, e->elems, e->target_offset,
 612                                      e->next_offset);
 613         if (err)
 614                 return err;
 615
 616         /* Check hooks & underflows */
 617         for (h = 0; h < NF_INET_NUMHOOKS; h++) {
 618                 if (!(valid_hooks & (1 << h)))
 619                         continue;
 620                 if ((unsigned char *)e - base == hook_entries[h])
 621                         newinfo->hook_entry[h] = hook_entries[h];
 622                 if ((unsigned char *)e - base == underflows[h]) {
 623                         if (!check_underflow(e))
 624                                 return -EINVAL;
 625
 626                         newinfo->underflow[h] = underflows[h];
 627                 }
 628         }
 629
 630         /* Clear counters and comefrom */
 631         e->counters = ((struct xt_counters) { 0, 0 });
 632         e->comefrom = 0;
 633         return 0;
 634 }
 635
 636 static void
 637 cleanup_entry(struct ipt_entry *e, struct net *net)
 638 {
 639         struct xt_tgdtor_param par;
 640         struct xt_entry_target *t;
 641         struct xt_entry_match *ematch;
 642
 643         /* Cleanup all matches */
 644         xt_ematch_foreach(ematch, e)
 645                 cleanup_match(ematch, net);
 646         t = ipt_get_target(e);
 647
 648         par.net      = net;
 649         par.target   = t->u.kernel.target;
 650         par.targinfo = t->data;
 651         par.family   = NFPROTO_IPV4;
 652         if (par.target->destroy != NULL)
 653                 par.target->destroy(&par);
 654         module_put(par.target->me);
 655         xt_percpu_counter_free(&e->counters);
 656 }
 657
 658 /* Checks and translates the user-supplied table segment (held in
 659    newinfo) */
 660 static int
 661 translate_table(struct net *net, struct xt_table_info *newinfo, void *entry0,
 662                 const struct ipt_replace *repl)
 663 {
 664         struct xt_percpu_counter_alloc_state alloc_state = { 0 };
 665         struct ipt_entry *iter;
 666         unsigned int *offsets;
 667         unsigned int i;
 668         int ret = 0;
 669
 670         newinfo->size = repl->size;
 671         newinfo->number = repl->num_entries;
 672
 673         /* Init all hooks to impossible value. */
 674         for (i = 0; i < NF_INET_NUMHOOKS; i++) {
 675                 newinfo->hook_entry[i] = 0xFFFFFFFF;
 676                 newinfo->underflow[i] = 0xFFFFFFFF;
 677         }
 678
 679         offsets = xt_alloc_entry_offsets(newinfo->number);
 680         if (!offsets)
 681                 return -ENOMEM;
 682         i = 0;
 683         /* Walk through entries, checking offsets. */
 684         xt_entry_foreach(iter, entry0, newinfo->size) {
 685                 ret = check_entry_size_and_hooks(iter, newinfo, entry0,
 686                                                  entry0 + repl->size,
 687                                                  repl->hook_entry,
 688                                                  repl->underflow,
 689                                                  repl->valid_hooks);
 690                 if (ret != 0)
 691                         goto out_free;
 692                 if (i < repl->num_entries)
 693                         offsets[i] = (void *)iter - entry0;
 694                 ++i;
 695                 if (strcmp(ipt_get_target(iter)->u.user.name,
 696                     XT_ERROR_TARGET) == 0)
 697                         ++newinfo->stacksize;
 698         }
 699
 700         ret = -EINVAL;
 701         if (i != repl->num_entries)
 702                 goto out_free;
 703
 704         ret = xt_check_table_hooks(newinfo, repl->valid_hooks);
 705         if (ret)
 706                 goto out_free;
 707
 708         if (!mark_source_chains(newinfo, repl->valid_hooks, entry0, offsets)) {
 709                 ret = -ELOOP;
 710                 goto out_free;
 711         }
 712         kvfree(offsets);
 713
 714         /* Finally, each sanity check must pass */
 715         i = 0;
 716         xt_entry_foreach(iter, entry0, newinfo->size) {
 717                 ret = find_check_entry(iter, net, repl->name, repl->size,
 718                                        &alloc_state);
 719                 if (ret != 0)
 720                         break;
 721                 ++i;
 722         }
 723
 724         if (ret != 0) {
 725                 xt_entry_foreach(iter, entry0, newinfo->size) {
 726                         if (i-- == 0)
 727                                 break;
 728                         cleanup_entry(iter, net);
 729                 }
 730                 return ret;
 731         }
 732
 733         return ret;
 734  out_free:
 735         kvfree(offsets);
 736         return ret;
 737 }
 738
 739 static void
 740 get_counters(const struct xt_table_info *t,
 741              struct xt_counters counters[])
 742 {
 743         struct ipt_entry *iter;
 744         unsigned int cpu;
 745         unsigned int i;
 746
 747         for_each_possible_cpu(cpu) {
 748                 seqcount_t *s = &per_cpu(xt_recseq, cpu);
 749
 750                 i = 0;
 751                 xt_entry_foreach(iter, t->entries, t->size) {
 752                         struct xt_counters *tmp;
 753                         u64 bcnt, pcnt;
 754                         unsigned int start;
 755
 756                         tmp = xt_get_per_cpu_counter(&iter->counters, cpu);
 757                         do {
 758                                 start = read_seqcount_begin(s);
 759                                 bcnt = tmp->bcnt;
 760                                 pcnt = tmp->pcnt;
 761                         } while (read_seqcount_retry(s, start));
 762
 763                         ADD_COUNTER(counters[i], bcnt, pcnt);
 764                         ++i; /* macro does multi eval of i */
 765                         cond_resched();
 766                 }
 767         }
 768 }
 769
 770 static void get_old_counters(const struct xt_table_info *t,
 771                              struct xt_counters counters[])
 772 {
 773         struct ipt_entry *iter;
 774         unsigned int cpu, i;
 775
 776         for_each_possible_cpu(cpu) {
 777                 i = 0;
 778                 xt_entry_foreach(iter, t->entries, t->size) {
 779                         const struct xt_counters *tmp;
 780
 781                         tmp = xt_get_per_cpu_counter(&iter->counters, cpu);
 782                         ADD_COUNTER(counters[i], tmp->bcnt, tmp->pcnt);
 783                         ++i; /* macro does multi eval of i */
 784                 }
 785
 786                 cond_resched();
 787         }
 788 }
 789
 790 static struct xt_counters *alloc_counters(const struct xt_table *table)
 791 {
 792         unsigned int countersize;
 793         struct xt_counters *counters;
 794         const struct xt_table_info *private = table->private;
 795
 796         /* We need atomic snapshot of counters: rest doesn't change
 797            (other than comefrom, which userspace doesn't care
 798            about). */
 799         countersize = sizeof(struct xt_counters) * private->number;
 800         counters = vzalloc(countersize);
 801
 802         if (counters == NULL)
 803                 return ERR_PTR(-ENOMEM);
 804
 805         get_counters(private, counters);
 806
 807         return counters;
 808 }
 809
 810 static int
 811 copy_entries_to_user(unsigned int total_size,
 812                      const struct xt_table *table,
 813                      void __user *userptr)
 814 {
 815         unsigned int off, num;
 816         const struct ipt_entry *e;
 817         struct xt_counters *counters;
 818         const struct xt_table_info *private = table->private;
 819         int ret = 0;
 820         const void *loc_cpu_entry;
 821
 822         counters = alloc_counters(table);
 823         if (IS_ERR(counters))
 824                 return PTR_ERR(counters);
 825
 826         loc_cpu_entry = private->entries;
 827
 828         /* FIXME: use iterator macros --RR */
 829         /* ... then go back and fix counters and names */
 830         for (off = 0, num = 0; off < total_size; off += e->next_offset, num++){
 831                 unsigned int i;
 832                 const struct xt_entry_match *m;
 833                 const struct xt_entry_target *t;
 834
 835                 e = loc_cpu_entry + off;
 836                 if (copy_to_user(userptr + off, e, sizeof(*e))) {
 837                         ret = -EFAULT;
 838                         goto free_counters;
 839                 }
 840                 if (copy_to_user(userptr + off
 841                                  + offsetof(struct ipt_entry, counters),
 842                                  &counters[num],
 843                                  sizeof(counters[num])) != 0) {
 844                         ret = -EFAULT;
 845                         goto free_counters;
 846                 }
 847
 848                 for (i = sizeof(struct ipt_entry);
 849                      i < e->target_offset;
 850                      i += m->u.match_size) {
 851                         m = (void *)e + i;
 852
 853                         if (xt_match_to_user(m, userptr + off + i)) {
 854                                 ret = -EFAULT;
 855                                 goto free_counters;
 856                         }
 857                 }
 858
 859                 t = ipt_get_target_c(e);
 860                 if (xt_target_to_user(t, userptr + off + e->target_offset)) {
 861                         ret = -EFAULT;
 862                         goto free_counters;
 863                 }
 864         }
 865
 866  free_counters:
 867         vfree(counters);
 868         return ret;
 869 }
 870
 871 #ifdef CONFIG_COMPAT
 872 static void compat_standard_from_user(void *dst, const void *src)
 873 {
 874         int v = *(compat_int_t *)src;
 875
 876         if (v > 0)
 877                 v += xt_compat_calc_jump(AF_INET, v);
 878         memcpy(dst, &v, sizeof(v));
 879 }
 880
 881 static int compat_standard_to_user(void __user *dst, const void *src)
 882 {
 883         compat_int_t cv = *(int *)src;
 884
 885         if (cv > 0)
 886                 cv -= xt_compat_calc_jump(AF_INET, cv);
 887         return copy_to_user(dst, &cv, sizeof(cv)) ? -EFAULT : 0;
 888 }
 889
 890 static int compat_calc_entry(const struct ipt_entry *e,
 891                              const struct xt_table_info *info,
 892                              const void *base, struct xt_table_info *newinfo)
 893 {
 894         const struct xt_entry_match *ematch;
 895         const struct xt_entry_target *t;
 896         unsigned int entry_offset;
 897         int off, i, ret;
 898
 899         off = sizeof(struct ipt_entry) - sizeof(struct compat_ipt_entry);
 900         entry_offset = (void *)e - base;
 901         xt_ematch_foreach(ematch, e)
 902                 off += xt_compat_match_offset(ematch->u.kernel.match);
 903         t = ipt_get_target_c(e);
 904         off += xt_compat_target_offset(t->u.kernel.target);
 905         newinfo->size -= off;
 906         ret = xt_compat_add_offset(AF_INET, entry_offset, off);
 907         if (ret)
 908                 return ret;
 909
 910         for (i = 0; i < NF_INET_NUMHOOKS; i++) {
 911                 if (info->hook_entry[i] &&
 912                     (e < (struct ipt_entry *)(base + info->hook_entry[i])))
 913                         newinfo->hook_entry[i] -= off;
 914                 if (info->underflow[i] &&
 915                     (e < (struct ipt_entry *)(base + info->underflow[i])))
 916                         newinfo->underflow[i] -= off;
 917         }
 918         return 0;
 919 }
 920
 921 static int compat_table_info(const struct xt_table_info *info,
 922                              struct xt_table_info *newinfo)
 923 {
 924         struct ipt_entry *iter;
 925         const void *loc_cpu_entry;
 926         int ret;
 927
 928         if (!newinfo || !info)
 929                 return -EINVAL;
 930
 931         /* we dont care about newinfo->entries */
 932         memcpy(newinfo, info, offsetof(struct xt_table_info, entries));
 933         newinfo->initial_entries = 0;
 934         loc_cpu_entry = info->entries;
 935         ret = xt_compat_init_offsets(AF_INET, info->number);
 936         if (ret)
 937                 return ret;
 938         xt_entry_foreach(iter, loc_cpu_entry, info->size) {
 939                 ret = compat_calc_entry(iter, info, loc_cpu_entry, newinfo);
 940                 if (ret != 0)
 941                         return ret;
 942         }
 943         return 0;
 944 }
 945 #endif
 946
 947 static int get_info(struct net *net, void __user *user,
 948                     const int *len, int compat)
 949 {
 950         char name[XT_TABLE_MAXNAMELEN];
 951         struct xt_table *t;
 952         int ret;
 953
 954         if (*len != sizeof(struct ipt_getinfo))
 955                 return -EINVAL;
 956
 957         if (copy_from_user(name, user, sizeof(name)) != 0)
 958                 return -EFAULT;
 959
 960         name[XT_TABLE_MAXNAMELEN-1] = '\0';
 961 #ifdef CONFIG_COMPAT
 962         if (compat)
 963                 xt_compat_lock(AF_INET);
 964 #endif
 965         t = xt_request_find_table_lock(net, AF_INET, name);
 966         if (!IS_ERR(t)) {
 967                 struct ipt_getinfo info;
 968                 const struct xt_table_info *private = t->private;
 969 #ifdef CONFIG_COMPAT
 970                 struct xt_table_info tmp;
 971
 972                 if (compat) {
 973                         ret = compat_table_info(private, &tmp);
 974                         xt_compat_flush_offsets(AF_INET);
 975                         private = &tmp;
 976                 }
 977 #endif
 978                 memset(&info, 0, sizeof(info));
 979                 info.valid_hooks = t->valid_hooks;
 980                 memcpy(info.hook_entry, private->hook_entry,
 981                        sizeof(info.hook_entry));
 982                 memcpy(info.underflow, private->underflow,
 983                        sizeof(info.underflow));
 984                 info.num_entries = private->number;
 985                 info.size = private->size;
 986                 strcpy(info.name, name);
 987
 988                 if (copy_to_user(user, &info, *len) != 0)
 989                         ret = -EFAULT;
 990                 else
 991                         ret = 0;
 992
 993                 xt_table_unlock(t);
 994                 module_put(t->me);
 995         } else
 996                 ret = PTR_ERR(t);
 997 #ifdef CONFIG_COMPAT
 998         if (compat)
 999                 xt_compat_unlock(AF_INET);
1000 #endif
1001         return ret;
1002 }
1003
1004 static int
1005 get_entries(struct net *net, struct ipt_get_entries __user *uptr,
1006             const int *len)
1007 {
1008         int ret;
1009         struct ipt_get_entries get;
1010         struct xt_table *t;
1011
1012         if (*len < sizeof(get))
1013                 return -EINVAL;
1014         if (copy_from_user(&get, uptr, sizeof(get)) != 0)
1015                 return -EFAULT;
1016         if (*len != sizeof(struct ipt_get_entries) + get.size)
1017                 return -EINVAL;
1018         get.name[sizeof(get.name) - 1] = '\0';
1019
1020         t = xt_find_table_lock(net, AF_INET, get.name);
1021         if (!IS_ERR(t)) {
1022                 const struct xt_table_info *private = t->private;
1023                 if (get.size == private->size)
1024                         ret = copy_entries_to_user(private->size,
1025                                                    t, uptr->entrytable);
1026                 else
1027                         ret = -EAGAIN;
1028
1029                 module_put(t->me);
1030                 xt_table_unlock(t);
1031         } else
1032                 ret = PTR_ERR(t);
1033
1034         return ret;
1035 }
1036
1037 static int
1038 __do_replace(struct net *net, const char *name, unsigned int valid_hooks,
1039              struct xt_table_info *newinfo, unsigned int num_counters,
1040              void __user *counters_ptr)
1041 {
1042         int ret;
1043         struct xt_table *t;
1044         struct xt_table_info *oldinfo;
1045         struct xt_counters *counters;
1046         struct ipt_entry *iter;
1047
1048         ret = 0;
1049         counters = xt_counters_alloc(num_counters);
1050         if (!counters) {
1051                 ret = -ENOMEM;
1052                 goto out;
1053         }
1054
1055         t = xt_request_find_table_lock(net, AF_INET, name);
1056         if (IS_ERR(t)) {
1057                 ret = PTR_ERR(t);
1058                 goto free_newinfo_counters_untrans;
1059         }
1060
1061         /* You lied! */
1062         if (valid_hooks != t->valid_hooks) {
1063                 ret = -EINVAL;
1064                 goto put_module;
1065         }
1066
1067         oldinfo = xt_replace_table(t, num_counters, newinfo, &ret);
1068         if (!oldinfo)
1069                 goto put_module;
1070
1071         /* Update module usage count based on number of rules */
1072         if ((oldinfo->number > oldinfo->initial_entries) ||
1073             (newinfo->number <= oldinfo->initial_entries))
1074                 module_put(t->me);
1075         if ((oldinfo->number > oldinfo->initial_entries) &&
1076             (newinfo->number <= oldinfo->initial_entries))
1077                 module_put(t->me);
1078
1079         xt_table_unlock(t);
1080
1081         get_old_counters(oldinfo, counters);
1082
1083         /* Decrease module usage counts and free resource */
1084         xt_entry_foreach(iter, oldinfo->entries, oldinfo->size)
1085                 cleanup_entry(iter, net);
1086
1087         xt_free_table_info(oldinfo);
1088         if (copy_to_user(counters_ptr, counters,
1089                          sizeof(struct xt_counters) * num_counters) != 0) {
1090                 /* Silent error, can't fail, new table is already in place */
1091                 net_warn_ratelimited("iptables: counters copy to user failed while replacing table\n");
1092         }
1093         vfree(counters);
1094         return ret;
1095
1096  put_module:
1097         module_put(t->me);
1098         xt_table_unlock(t);
1099  free_newinfo_counters_untrans:
1100         vfree(counters);
1101  out:
1102         return ret;
1103 }
1104
1105 static int
1106 do_replace(struct net *net, const void __user *user, unsigned int len)
1107 {
1108         int ret;
1109         struct ipt_replace tmp;
1110         struct xt_table_info *newinfo;
1111         void *loc_cpu_entry;
1112         struct ipt_entry *iter;
1113
1114         if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
1115                 return -EFAULT;
1116
1117         /* overflow check */
1118         if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
1119                 return -ENOMEM;
1120         if (tmp.num_counters == 0)
1121                 return -EINVAL;
1122
1123         tmp.name[sizeof(tmp.name)-1] = 0;
1124
1125         newinfo = xt_alloc_table_info(tmp.size);
1126         if (!newinfo)
1127                 return -ENOMEM;
1128
1129         loc_cpu_entry = newinfo->entries;
1130         if (copy_from_user(loc_cpu_entry, user + sizeof(tmp),
1131                            tmp.size) != 0) {
1132                 ret = -EFAULT;
1133                 goto free_newinfo;
1134         }
1135
1136         ret = translate_table(net, newinfo, loc_cpu_entry, &tmp);
1137         if (ret != 0)
1138                 goto free_newinfo;
1139
1140         ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo,
1141                            tmp.num_counters, tmp.counters);
1142         if (ret)
1143                 goto free_newinfo_untrans;
1144         return 0;
1145
1146  free_newinfo_untrans:
1147         xt_entry_foreach(iter, loc_cpu_entry, newinfo->size)
1148                 cleanup_entry(iter, net);
1149  free_newinfo:
1150         xt_free_table_info(newinfo);
1151         return ret;
1152 }
1153
1154 static int
1155 do_add_counters(struct net *net, const void __user *user,
1156                 unsigned int len, int compat)
1157 {
1158         unsigned int i;
1159         struct xt_counters_info tmp;
1160         struct xt_counters *paddc;
1161         struct xt_table *t;
1162         const struct xt_table_info *private;
1163         int ret = 0;
1164         struct ipt_entry *iter;
1165         unsigned int addend;
1166
1167         paddc = xt_copy_counters_from_user(user, len, &tmp, compat);
1168         if (IS_ERR(paddc))
1169                 return PTR_ERR(paddc);
1170
1171         t = xt_find_table_lock(net, AF_INET, tmp.name);
1172         if (IS_ERR(t)) {
1173                 ret = PTR_ERR(t);
1174                 goto free;
1175         }
1176
1177         local_bh_disable();
1178         private = t->private;
1179         if (private->number != tmp.num_counters) {
1180                 ret = -EINVAL;
1181                 goto unlock_up_free;
1182         }
1183
1184         i = 0;
1185         addend = xt_write_recseq_begin();
1186         xt_entry_foreach(iter, private->entries, private->size) {
1187                 struct xt_counters *tmp;
1188
1189                 tmp = xt_get_this_cpu_counter(&iter->counters);
1190                 ADD_COUNTER(*tmp, paddc[i].bcnt, paddc[i].pcnt);
1191                 ++i;
1192         }
1193         xt_write_recseq_end(addend);
1194  unlock_up_free:
1195         local_bh_enable();
1196         xt_table_unlock(t);
1197         module_put(t->me);
1198  free:
1199         vfree(paddc);
1200
1201         return ret;
1202 }
1203
1204 #ifdef CONFIG_COMPAT
1205 struct compat_ipt_replace {
1206         char                    name[XT_TABLE_MAXNAMELEN];
1207         u32                     valid_hooks;
1208         u32                     num_entries;
1209         u32                     size;
1210         u32                     hook_entry[NF_INET_NUMHOOKS];
1211         u32                     underflow[NF_INET_NUMHOOKS];
1212         u32                     num_counters;
1213         compat_uptr_t           counters;       /* struct xt_counters * */
1214         struct compat_ipt_entry entries[0];
1215 };
1216
1217 static int
1218 compat_copy_entry_to_user(struct ipt_entry *e, void __user **dstptr,
1219                           unsigned int *size, struct xt_counters *counters,
1220                           unsigned int i)
1221 {
1222         struct xt_entry_target *t;
1223         struct compat_ipt_entry __user *ce;
1224         u_int16_t target_offset, next_offset;
1225         compat_uint_t origsize;
1226         const struct xt_entry_match *ematch;
1227         int ret = 0;
1228
1229         origsize = *size;
1230         ce = *dstptr;
1231         if (copy_to_user(ce, e, sizeof(struct ipt_entry)) != 0 ||
1232             copy_to_user(&ce->counters, &counters[i],
1233             sizeof(counters[i])) != 0)
1234                 return -EFAULT;
1235
1236         *dstptr += sizeof(struct compat_ipt_entry);
1237         *size -= sizeof(struct ipt_entry) - sizeof(struct compat_ipt_entry);
1238
1239         xt_ematch_foreach(ematch, e) {
1240                 ret = xt_compat_match_to_user(ematch, dstptr, size);
1241                 if (ret != 0)
1242                         return ret;
1243         }
1244         target_offset = e->target_offset - (origsize - *size);
1245         t = ipt_get_target(e);
1246         ret = xt_compat_target_to_user(t, dstptr, size);
1247         if (ret)
1248                 return ret;
1249         next_offset = e->next_offset - (origsize - *size);
1250         if (put_user(target_offset, &ce->target_offset) != 0 ||
1251             put_user(next_offset, &ce->next_offset) != 0)
1252                 return -EFAULT;
1253         return 0;
1254 }
1255
1256 static int
1257 compat_find_calc_match(struct xt_entry_match *m,
1258                        const struct ipt_ip *ip,
1259                        int *size)
1260 {
1261         struct xt_match *match;
1262
1263         match = xt_request_find_match(NFPROTO_IPV4, m->u.user.name,
1264                                       m->u.user.revision);
1265         if (IS_ERR(match))
1266                 return PTR_ERR(match);
1267
1268         m->u.kernel.match = match;
1269         *size += xt_compat_match_offset(match);
1270         return 0;
1271 }
1272
1273 static void compat_release_entry(struct compat_ipt_entry *e)
1274 {
1275         struct xt_entry_target *t;
1276         struct xt_entry_match *ematch;
1277
1278         /* Cleanup all matches */
1279         xt_ematch_foreach(ematch, e)
1280                 module_put(ematch->u.kernel.match->me);
1281         t = compat_ipt_get_target(e);
1282         module_put(t->u.kernel.target->me);
1283 }
1284
1285 static int
1286 check_compat_entry_size_and_hooks(struct compat_ipt_entry *e,
1287                                   struct xt_table_info *newinfo,
1288                                   unsigned int *size,
1289                                   const unsigned char *base,
1290                                   const unsigned char *limit)
1291 {
1292         struct xt_entry_match *ematch;
1293         struct xt_entry_target *t;
1294         struct xt_target *target;
1295         unsigned int entry_offset;
1296         unsigned int j;
1297         int ret, off;
1298
1299         if ((unsigned long)e % __alignof__(struct compat_ipt_entry) != 0 ||
1300             (unsigned char *)e + sizeof(struct compat_ipt_entry) >= limit ||
1301             (unsigned char *)e + e->next_offset > limit)
1302                 return -EINVAL;
1303
1304         if (e->next_offset < sizeof(struct compat_ipt_entry) +
1305                              sizeof(struct compat_xt_entry_target))
1306                 return -EINVAL;
1307
1308         if (!ip_checkentry(&e->ip))
1309                 return -EINVAL;
1310
1311         ret = xt_compat_check_entry_offsets(e, e->elems,
1312                                             e->target_offset, e->next_offset);
1313         if (ret)
1314                 return ret;
1315
1316         off = sizeof(struct ipt_entry) - sizeof(struct compat_ipt_entry);
1317         entry_offset = (void *)e - (void *)base;
1318         j = 0;
1319         xt_ematch_foreach(ematch, e) {
1320                 ret = compat_find_calc_match(ematch, &e->ip, &off);
1321                 if (ret != 0)
1322                         goto release_matches;
1323                 ++j;
1324         }
1325
1326         t = compat_ipt_get_target(e);
1327         target = xt_request_find_target(NFPROTO_IPV4, t->u.user.name,
1328                                         t->u.user.revision);
1329         if (IS_ERR(target)) {
1330                 ret = PTR_ERR(target);
1331                 goto release_matches;
1332         }
1333         t->u.kernel.target = target;
1334
1335         off += xt_compat_target_offset(target);
1336         *size += off;
1337         ret = xt_compat_add_offset(AF_INET, entry_offset, off);
1338         if (ret)
1339                 goto out;
1340
1341         return 0;
1342
1343 out:
1344         module_put(t->u.kernel.target->me);
1345 release_matches:
1346         xt_ematch_foreach(ematch, e) {
1347                 if (j-- == 0)
1348                         break;
1349                 module_put(ematch->u.kernel.match->me);
1350         }
1351         return ret;
1352 }
1353
1354 static void
1355 compat_copy_entry_from_user(struct compat_ipt_entry *e, void **dstptr,
1356                             unsigned int *size,
1357                             struct xt_table_info *newinfo, unsigned char *base)
1358 {
1359         struct xt_entry_target *t;
1360         struct ipt_entry *de;
1361         unsigned int origsize;
1362         int h;
1363         struct xt_entry_match *ematch;
1364
1365         origsize = *size;
1366         de = *dstptr;
1367         memcpy(de, e, sizeof(struct ipt_entry));
1368         memcpy(&de->counters, &e->counters, sizeof(e->counters));
1369
1370         *dstptr += sizeof(struct ipt_entry);
1371         *size += sizeof(struct ipt_entry) - sizeof(struct compat_ipt_entry);
1372
1373         xt_ematch_foreach(ematch, e)
1374                 xt_compat_match_from_user(ematch, dstptr, size);
1375
1376         de->target_offset = e->target_offset - (origsize - *size);
1377         t = compat_ipt_get_target(e);
1378         xt_compat_target_from_user(t, dstptr, size);
1379
1380         de->next_offset = e->next_offset - (origsize - *size);
1381
1382         for (h = 0; h < NF_INET_NUMHOOKS; h++) {
1383                 if ((unsigned char *)de - base < newinfo->hook_entry[h])
1384                         newinfo->hook_entry[h] -= origsize - *size;
1385                 if ((unsigned char *)de - base < newinfo->underflow[h])
1386                         newinfo->underflow[h] -= origsize - *size;
1387         }
1388 }
1389
1390 static int
1391 translate_compat_table(struct net *net,
1392                        struct xt_table_info **pinfo,
1393                        void **pentry0,
1394                        const struct compat_ipt_replace *compatr)
1395 {
1396         unsigned int i, j;
1397         struct xt_table_info *newinfo, *info;
1398         void *pos, *entry0, *entry1;
1399         struct compat_ipt_entry *iter0;
1400         struct ipt_replace repl;
1401         unsigned int size;
1402         int ret;
1403
1404         info = *pinfo;
1405         entry0 = *pentry0;
1406         size = compatr->size;
1407         info->number = compatr->num_entries;
1408
1409         j = 0;
1410         xt_compat_lock(AF_INET);
1411         ret = xt_compat_init_offsets(AF_INET, compatr->num_entries);
1412         if (ret)
1413                 goto out_unlock;
1414         /* Walk through entries, checking offsets. */
1415         xt_entry_foreach(iter0, entry0, compatr->size) {
1416                 ret = check_compat_entry_size_and_hooks(iter0, info, &size,
1417                                                         entry0,
1418                                                         entry0 + compatr->size);
1419                 if (ret != 0)
1420                         goto out_unlock;
1421                 ++j;
1422         }
1423
1424         ret = -EINVAL;
1425         if (j != compatr->num_entries)
1426                 goto out_unlock;
1427
1428         ret = -ENOMEM;
1429         newinfo = xt_alloc_table_info(size);
1430         if (!newinfo)
1431                 goto out_unlock;
1432
1433         newinfo->number = compatr->num_entries;
1434         for (i = 0; i < NF_INET_NUMHOOKS; i++) {
1435                 newinfo->hook_entry[i] = compatr->hook_entry[i];
1436                 newinfo->underflow[i] = compatr->underflow[i];
1437         }
1438         entry1 = newinfo->entries;
1439         pos = entry1;
1440         size = compatr->size;
1441         xt_entry_foreach(iter0, entry0, compatr->size)
1442                 compat_copy_entry_from_user(iter0, &pos, &size,
1443                                             newinfo, entry1);
1444
1445         /* all module references in entry0 are now gone.
1446          * entry1/newinfo contains a 64bit ruleset that looks exactly as
1447          * generated by 64bit userspace.
1448          *
1449          * Call standard translate_table() to validate all hook_entrys,
1450          * underflows, check for loops, etc.
1451          */
1452         xt_compat_flush_offsets(AF_INET);
1453         xt_compat_unlock(AF_INET);
1454
1455         memcpy(&repl, compatr, sizeof(*compatr));
1456
1457         for (i = 0; i < NF_INET_NUMHOOKS; i++) {
1458                 repl.hook_entry[i] = newinfo->hook_entry[i];
1459                 repl.underflow[i] = newinfo->underflow[i];
1460         }
1461
1462         repl.num_counters = 0;
1463         repl.counters = NULL;
1464         repl.size = newinfo->size;
1465         ret = translate_table(net, newinfo, entry1, &repl);
1466         if (ret)
1467                 goto free_newinfo;
1468
1469         *pinfo = newinfo;
1470         *pentry0 = entry1;
1471         xt_free_table_info(info);
1472         return 0;
1473
1474 free_newinfo:
1475         xt_free_table_info(newinfo);
1476         return ret;
1477 out_unlock:
1478         xt_compat_flush_offsets(AF_INET);
1479         xt_compat_unlock(AF_INET);
1480         xt_entry_foreach(iter0, entry0, compatr->size) {
1481                 if (j-- == 0)
1482                         break;
1483                 compat_release_entry(iter0);
1484         }
1485         return ret;
1486 }
1487
1488 static int
1489 compat_do_replace(struct net *net, void __user *user, unsigned int len)
1490 {
1491         int ret;
1492         struct compat_ipt_replace tmp;
1493         struct xt_table_info *newinfo;
1494         void *loc_cpu_entry;
1495         struct ipt_entry *iter;
1496
1497         if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
1498                 return -EFAULT;
1499
1500         /* overflow check */
1501         if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
1502                 return -ENOMEM;
1503         if (tmp.num_counters == 0)
1504                 return -EINVAL;
1505
1506         tmp.name[sizeof(tmp.name)-1] = 0;
1507
1508         newinfo = xt_alloc_table_info(tmp.size);
1509         if (!newinfo)
1510                 return -ENOMEM;
1511
1512         loc_cpu_entry = newinfo->entries;
1513         if (copy_from_user(loc_cpu_entry, user + sizeof(tmp),
1514                            tmp.size) != 0) {
1515                 ret = -EFAULT;
1516                 goto free_newinfo;
1517         }
1518
1519         ret = translate_compat_table(net, &newinfo, &loc_cpu_entry, &tmp);
1520         if (ret != 0)
1521                 goto free_newinfo;
1522
1523         ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo,
1524                            tmp.num_counters, compat_ptr(tmp.counters));
1525         if (ret)
1526                 goto free_newinfo_untrans;
1527         return 0;
1528
1529  free_newinfo_untrans:
1530         xt_entry_foreach(iter, loc_cpu_entry, newinfo->size)
1531                 cleanup_entry(iter, net);
1532  free_newinfo:
1533         xt_free_table_info(newinfo);
1534         return ret;
1535 }
1536
1537 static int
1538 compat_do_ipt_set_ctl(struct sock *sk,  int cmd, void __user *user,
1539                       unsigned int len)
1540 {
1541         int ret;
1542
1543         if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1544                 return -EPERM;
1545
1546         switch (cmd) {
1547         case IPT_SO_SET_REPLACE:
1548                 ret = compat_do_replace(sock_net(sk), user, len);
1549                 break;
1550
1551         case IPT_SO_SET_ADD_COUNTERS:
1552                 ret = do_add_counters(sock_net(sk), user, len, 1);
1553                 break;
1554
1555         default:
1556                 ret = -EINVAL;
1557         }
1558
1559         return ret;
1560 }
1561
1562 struct compat_ipt_get_entries {
1563         char name[XT_TABLE_MAXNAMELEN];
1564         compat_uint_t size;
1565         struct compat_ipt_entry entrytable[0];
1566 };
1567
1568 static int
1569 compat_copy_entries_to_user(unsigned int total_size, struct xt_table *table,
1570                             void __user *userptr)
1571 {
1572         struct xt_counters *counters;
1573         const struct xt_table_info *private = table->private;
1574         void __user *pos;
1575         unsigned int size;
1576         int ret = 0;
1577         unsigned int i = 0;
1578         struct ipt_entry *iter;
1579
1580         counters = alloc_counters(table);
1581         if (IS_ERR(counters))
1582                 return PTR_ERR(counters);
1583
1584         pos = userptr;
1585         size = total_size;
1586         xt_entry_foreach(iter, private->entries, total_size) {
1587                 ret = compat_copy_entry_to_user(iter, &pos,
1588                                                 &size, counters, i++);
1589                 if (ret != 0)
1590                         break;
1591         }
1592
1593         vfree(counters);
1594         return ret;
1595 }
1596
1597 static int
1598 compat_get_entries(struct net *net, struct compat_ipt_get_entries __user *uptr,
1599                    int *len)
1600 {
1601         int ret;
1602         struct compat_ipt_get_entries get;
1603         struct xt_table *t;
1604
1605         if (*len < sizeof(get))
1606                 return -EINVAL;
1607
1608         if (copy_from_user(&get, uptr, sizeof(get)) != 0)
1609                 return -EFAULT;
1610
1611         if (*len != sizeof(struct compat_ipt_get_entries) + get.size)
1612                 return -EINVAL;
1613
1614         get.name[sizeof(get.name) - 1] = '\0';
1615
1616         xt_compat_lock(AF_INET);
1617         t = xt_find_table_lock(net, AF_INET, get.name);
1618         if (!IS_ERR(t)) {
1619                 const struct xt_table_info *private = t->private;
1620                 struct xt_table_info info;
1621                 ret = compat_table_info(private, &info);
1622                 if (!ret && get.size == info.size)
1623                         ret = compat_copy_entries_to_user(private->size,
1624                                                           t, uptr->entrytable);
1625                 else if (!ret)
1626                         ret = -EAGAIN;
1627
1628                 xt_compat_flush_offsets(AF_INET);
1629                 module_put(t->me);
1630                 xt_table_unlock(t);
1631         } else
1632                 ret = PTR_ERR(t);
1633
1634         xt_compat_unlock(AF_INET);
1635         return ret;
1636 }
1637
1638 static int do_ipt_get_ctl(struct sock *, int, void __user *, int *);
1639
1640 static int
1641 compat_do_ipt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
1642 {
1643         int ret;
1644
1645         if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1646                 return -EPERM;
1647
1648         switch (cmd) {
1649         case IPT_SO_GET_INFO:
1650                 ret = get_info(sock_net(sk), user, len, 1);
1651                 break;
1652         case IPT_SO_GET_ENTRIES:
1653                 ret = compat_get_entries(sock_net(sk), user, len);
1654                 break;
1655         default:
1656                 ret = do_ipt_get_ctl(sk, cmd, user, len);
1657         }
1658         return ret;
1659 }
1660 #endif
1661
1662 static int
1663 do_ipt_set_ctl(struct sock *sk, int cmd, void __user *user, unsigned int len)
1664 {
1665         int ret;
1666
1667         if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1668                 return -EPERM;
1669
1670         switch (cmd) {
1671         case IPT_SO_SET_REPLACE:
1672                 ret = do_replace(sock_net(sk), user, len);
1673                 break;
1674
1675         case IPT_SO_SET_ADD_COUNTERS:
1676                 ret = do_add_counters(sock_net(sk), user, len, 0);
1677                 break;
1678
1679         default:
1680                 ret = -EINVAL;
1681         }
1682
1683         return ret;
1684 }
1685
1686 static int
1687 do_ipt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
1688 {
1689         int ret;
1690
1691         if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1692                 return -EPERM;
1693
1694         switch (cmd) {
1695         case IPT_SO_GET_INFO:
1696                 ret = get_info(sock_net(sk), user, len, 0);
1697                 break;
1698
1699         case IPT_SO_GET_ENTRIES:
1700                 ret = get_entries(sock_net(sk), user, len);
1701                 break;
1702
1703         case IPT_SO_GET_REVISION_MATCH:
1704         case IPT_SO_GET_REVISION_TARGET: {
1705                 struct xt_get_revision rev;
1706                 int target;
1707
1708                 if (*len != sizeof(rev)) {
1709                         ret = -EINVAL;
1710                         break;
1711                 }
1712                 if (copy_from_user(&rev, user, sizeof(rev)) != 0) {
1713                         ret = -EFAULT;
1714                         break;
1715                 }
1716                 rev.name[sizeof(rev.name)-1] = 0;
1717
1718                 if (cmd == IPT_SO_GET_REVISION_TARGET)
1719                         target = 1;
1720                 else
1721                         target = 0;
1722
1723                 try_then_request_module(xt_find_revision(AF_INET, rev.name,
1724                                                          rev.revision,
1725                                                          target, &ret),
1726                                         "ipt_%s", rev.name);
1727                 break;
1728         }
1729
1730         default:
1731                 ret = -EINVAL;
1732         }
1733
1734         return ret;
1735 }
1736
1737 static void __ipt_unregister_table(struct net *net, struct xt_table *table)
1738 {
1739         struct xt_table_info *private;
1740         void *loc_cpu_entry;
1741         struct module *table_owner = table->me;
1742         struct ipt_entry *iter;
1743
1744         private = xt_unregister_table(table);
1745
1746         /* Decrease module usage counts and free resources */
1747         loc_cpu_entry = private->entries;
1748         xt_entry_foreach(iter, loc_cpu_entry, private->size)
1749                 cleanup_entry(iter, net);
1750         if (private->number > private->initial_entries)
1751                 module_put(table_owner);
1752         xt_free_table_info(private);
1753 }
1754
1755 int ipt_register_table(struct net *net, const struct xt_table *table,
1756                        const struct ipt_replace *repl,
1757                        const struct nf_hook_ops *ops, struct xt_table **res)
1758 {
1759         int ret;
1760         struct xt_table_info *newinfo;
1761         struct xt_table_info bootstrap = {0};
1762         void *loc_cpu_entry;
1763         struct xt_table *new_table;
1764
1765         newinfo = xt_alloc_table_info(repl->size);
1766         if (!newinfo)
1767                 return -ENOMEM;
1768
1769         loc_cpu_entry = newinfo->entries;
1770         memcpy(loc_cpu_entry, repl->entries, repl->size);
1771
1772         ret = translate_table(net, newinfo, loc_cpu_entry, repl);
1773         if (ret != 0)
1774                 goto out_free;
1775
1776         new_table = xt_register_table(net, table, &bootstrap, newinfo);
1777         if (IS_ERR(new_table)) {
1778                 ret = PTR_ERR(new_table);
1779                 goto out_free;
1780         }
1781
1782         /* set res now, will see skbs right after nf_register_net_hooks */
1783         WRITE_ONCE(*res, new_table);
1784         if (!ops)
1785                 return 0;
1786
1787         ret = nf_register_net_hooks(net, ops, hweight32(table->valid_hooks));
1788         if (ret != 0) {
1789                 __ipt_unregister_table(net, new_table);
1790                 *res = NULL;
1791         }
1792
1793         return ret;
1794
1795 out_free:
1796         xt_free_table_info(newinfo);
1797         return ret;
1798 }
1799
1800 void ipt_unregister_table(struct net *net, struct xt_table *table,
1801                           const struct nf_hook_ops *ops)
1802 {
1803         if (ops)
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                 .me         = THIS_MODULE,
1899         },
1900 };
1901
1902 static int __net_init ip_tables_net_init(struct net *net)
1903 {
1904         return xt_proto_init(net, NFPROTO_IPV4);
1905 }
1906
1907 static void __net_exit ip_tables_net_exit(struct net *net)
1908 {
1909         xt_proto_fini(net, NFPROTO_IPV4);
1910 }
1911
1912 static struct pernet_operations ip_tables_net_ops = {
1913         .init = ip_tables_net_init,
1914         .exit = ip_tables_net_exit,
1915 };
1916
1917 static int __init ip_tables_init(void)
1918 {
1919         int ret;
1920
1921         ret = register_pernet_subsys(&ip_tables_net_ops);
1922         if (ret < 0)
1923                 goto err1;
1924
1925         /* No one else will be downing sem now, so we won't sleep */
1926         ret = xt_register_targets(ipt_builtin_tg, ARRAY_SIZE(ipt_builtin_tg));
1927         if (ret < 0)
1928                 goto err2;
1929         ret = xt_register_matches(ipt_builtin_mt, ARRAY_SIZE(ipt_builtin_mt));
1930         if (ret < 0)
1931                 goto err4;
1932
1933         /* Register setsockopt */
1934         ret = nf_register_sockopt(&ipt_sockopts);
1935         if (ret < 0)
1936                 goto err5;
1937
1938         return 0;
1939
1940 err5:
1941         xt_unregister_matches(ipt_builtin_mt, ARRAY_SIZE(ipt_builtin_mt));
1942 err4:
1943         xt_unregister_targets(ipt_builtin_tg, ARRAY_SIZE(ipt_builtin_tg));
1944 err2:
1945         unregister_pernet_subsys(&ip_tables_net_ops);
1946 err1:
1947         return ret;
1948 }
1949
1950 static void __exit ip_tables_fini(void)
1951 {
1952         nf_unregister_sockopt(&ipt_sockopts);
1953
1954         xt_unregister_matches(ipt_builtin_mt, ARRAY_SIZE(ipt_builtin_mt));
1955         xt_unregister_targets(ipt_builtin_tg, ARRAY_SIZE(ipt_builtin_tg));
1956         unregister_pernet_subsys(&ip_tables_net_ops);
1957 }
1958
1959 EXPORT_SYMBOL(ipt_register_table);
1960 EXPORT_SYMBOL(ipt_unregister_table);
1961 EXPORT_SYMBOL(ipt_do_table);
1962 module_init(ip_tables_init);
1963 module_exit(ip_tables_fini);