linux/net/ipv6/netfilter/ip6_tables.c
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   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * Packet matching code.
   4 *
   5 * Copyright (C) 1999 Paul `Rusty' Russell & Michael J. Neuling
   6 * Copyright (C) 2000-2005 Netfilter Core Team <coreteam@netfilter.org>
   7 * Copyright (c) 2006-2010 Patrick McHardy <kaber@trash.net>
   8 */
   9
  10#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  11
  12#include <linux/kernel.h>
  13#include <linux/capability.h>
  14#include <linux/in.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/poison.h>
  21#include <linux/icmpv6.h>
  22#include <net/ipv6.h>
  23#include <net/compat.h>
  24#include <linux/uaccess.h>
  25#include <linux/mutex.h>
  26#include <linux/proc_fs.h>
  27#include <linux/err.h>
  28#include <linux/cpumask.h>
  29
  30#include <linux/netfilter_ipv6/ip6_tables.h>
  31#include <linux/netfilter/x_tables.h>
  32#include <net/netfilter/nf_log.h>
  33#include "../../netfilter/xt_repldata.h"
  34
  35MODULE_LICENSE("GPL");
  36MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
  37MODULE_DESCRIPTION("IPv6 packet filter");
  38MODULE_ALIAS("ip6t_icmp6");
  39
  40void *ip6t_alloc_initial_table(const struct xt_table *info)
  41{
  42        return xt_alloc_initial_table(ip6t, IP6T);
  43}
  44EXPORT_SYMBOL_GPL(ip6t_alloc_initial_table);
  45
  46/* Returns whether matches rule or not. */
  47/* Performance critical - called for every packet */
  48static inline bool
  49ip6_packet_match(const struct sk_buff *skb,
  50                 const char *indev,
  51                 const char *outdev,
  52                 const struct ip6t_ip6 *ip6info,
  53                 unsigned int *protoff,
  54                 int *fragoff, bool *hotdrop)
  55{
  56        unsigned long ret;
  57        const struct ipv6hdr *ipv6 = ipv6_hdr(skb);
  58
  59        if (NF_INVF(ip6info, IP6T_INV_SRCIP,
  60                    ipv6_masked_addr_cmp(&ipv6->saddr, &ip6info->smsk,
  61                                         &ip6info->src)) ||
  62            NF_INVF(ip6info, IP6T_INV_DSTIP,
  63                    ipv6_masked_addr_cmp(&ipv6->daddr, &ip6info->dmsk,
  64                                         &ip6info->dst)))
  65                return false;
  66
  67        ret = ifname_compare_aligned(indev, ip6info->iniface, ip6info->iniface_mask);
  68
  69        if (NF_INVF(ip6info, IP6T_INV_VIA_IN, ret != 0))
  70                return false;
  71
  72        ret = ifname_compare_aligned(outdev, ip6info->outiface, ip6info->outiface_mask);
  73
  74        if (NF_INVF(ip6info, IP6T_INV_VIA_OUT, ret != 0))
  75                return false;
  76
  77/* ... might want to do something with class and flowlabel here ... */
  78
  79        /* look for the desired protocol header */
  80        if (ip6info->flags & IP6T_F_PROTO) {
  81                int protohdr;
  82                unsigned short _frag_off;
  83
  84                protohdr = ipv6_find_hdr(skb, protoff, -1, &_frag_off, NULL);
  85                if (protohdr < 0) {
  86                        if (_frag_off == 0)
  87                                *hotdrop = true;
  88                        return false;
  89                }
  90                *fragoff = _frag_off;
  91
  92                if (ip6info->proto == protohdr) {
  93                        if (ip6info->invflags & IP6T_INV_PROTO)
  94                                return false;
  95
  96                        return true;
  97                }
  98
  99                /* We need match for the '-p all', too! */
 100                if ((ip6info->proto != 0) &&
 101                        !(ip6info->invflags & IP6T_INV_PROTO))
 102                        return false;
 103        }
 104        return true;
 105}
 106
 107/* should be ip6 safe */
 108static bool
 109ip6_checkentry(const struct ip6t_ip6 *ipv6)
 110{
 111        if (ipv6->flags & ~IP6T_F_MASK)
 112                return false;
 113        if (ipv6->invflags & ~IP6T_INV_MASK)
 114                return false;
 115
 116        return true;
 117}
 118
 119static unsigned int
 120ip6t_error(struct sk_buff *skb, const struct xt_action_param *par)
 121{
 122        net_info_ratelimited("error: `%s'\n", (const char *)par->targinfo);
 123
 124        return NF_DROP;
 125}
 126
 127static inline struct ip6t_entry *
 128get_entry(const void *base, unsigned int offset)
 129{
 130        return (struct ip6t_entry *)(base + offset);
 131}
 132
 133/* All zeroes == unconditional rule. */
 134/* Mildly perf critical (only if packet tracing is on) */
 135static inline bool unconditional(const struct ip6t_entry *e)
 136{
 137        static const struct ip6t_ip6 uncond;
 138
 139        return e->target_offset == sizeof(struct ip6t_entry) &&
 140               memcmp(&e->ipv6, &uncond, sizeof(uncond)) == 0;
 141}
 142
 143static inline const struct xt_entry_target *
 144ip6t_get_target_c(const struct ip6t_entry *e)
 145{
 146        return ip6t_get_target((struct ip6t_entry *)e);
 147}
 148
 149#if IS_ENABLED(CONFIG_NETFILTER_XT_TARGET_TRACE)
 150/* This cries for unification! */
 151static const char *const hooknames[] = {
 152        [NF_INET_PRE_ROUTING]           = "PREROUTING",
 153        [NF_INET_LOCAL_IN]              = "INPUT",
 154        [NF_INET_FORWARD]               = "FORWARD",
 155        [NF_INET_LOCAL_OUT]             = "OUTPUT",
 156        [NF_INET_POST_ROUTING]          = "POSTROUTING",
 157};
 158
 159enum nf_ip_trace_comments {
 160        NF_IP6_TRACE_COMMENT_RULE,
 161        NF_IP6_TRACE_COMMENT_RETURN,
 162        NF_IP6_TRACE_COMMENT_POLICY,
 163};
 164
 165static const char *const comments[] = {
 166        [NF_IP6_TRACE_COMMENT_RULE]     = "rule",
 167        [NF_IP6_TRACE_COMMENT_RETURN]   = "return",
 168        [NF_IP6_TRACE_COMMENT_POLICY]   = "policy",
 169};
 170
 171static const struct nf_loginfo trace_loginfo = {
 172        .type = NF_LOG_TYPE_LOG,
 173        .u = {
 174                .log = {
 175                        .level = LOGLEVEL_WARNING,
 176                        .logflags = NF_LOG_DEFAULT_MASK,
 177                },
 178        },
 179};
 180
 181/* Mildly perf critical (only if packet tracing is on) */
 182static inline int
 183get_chainname_rulenum(const struct ip6t_entry *s, const struct ip6t_entry *e,
 184                      const char *hookname, const char **chainname,
 185                      const char **comment, unsigned int *rulenum)
 186{
 187        const struct xt_standard_target *t = (void *)ip6t_get_target_c(s);
 188
 189        if (strcmp(t->target.u.kernel.target->name, XT_ERROR_TARGET) == 0) {
 190                /* Head of user chain: ERROR target with chainname */
 191                *chainname = t->target.data;
 192                (*rulenum) = 0;
 193        } else if (s == e) {
 194                (*rulenum)++;
 195
 196                if (unconditional(s) &&
 197                    strcmp(t->target.u.kernel.target->name,
 198                           XT_STANDARD_TARGET) == 0 &&
 199                    t->verdict < 0) {
 200                        /* Tail of chains: STANDARD target (return/policy) */
 201                        *comment = *chainname == hookname
 202                                ? comments[NF_IP6_TRACE_COMMENT_POLICY]
 203                                : comments[NF_IP6_TRACE_COMMENT_RETURN];
 204                }
 205                return 1;
 206        } else
 207                (*rulenum)++;
 208
 209        return 0;
 210}
 211
 212static void trace_packet(struct net *net,
 213                         const struct sk_buff *skb,
 214                         unsigned int hook,
 215                         const struct net_device *in,
 216                         const struct net_device *out,
 217                         const char *tablename,
 218                         const struct xt_table_info *private,
 219                         const struct ip6t_entry *e)
 220{
 221        const struct ip6t_entry *root;
 222        const char *hookname, *chainname, *comment;
 223        const struct ip6t_entry *iter;
 224        unsigned int rulenum = 0;
 225
 226        root = get_entry(private->entries, private->hook_entry[hook]);
 227
 228        hookname = chainname = hooknames[hook];
 229        comment = comments[NF_IP6_TRACE_COMMENT_RULE];
 230
 231        xt_entry_foreach(iter, root, private->size - private->hook_entry[hook])
 232                if (get_chainname_rulenum(iter, e, hookname,
 233                    &chainname, &comment, &rulenum) != 0)
 234                        break;
 235
 236        nf_log_trace(net, AF_INET6, hook, skb, in, out, &trace_loginfo,
 237                     "TRACE: %s:%s:%s:%u ",
 238                     tablename, chainname, comment, rulenum);
 239}
 240#endif
 241
 242static inline struct ip6t_entry *
 243ip6t_next_entry(const struct ip6t_entry *entry)
 244{
 245        return (void *)entry + entry->next_offset;
 246}
 247
 248/* Returns one of the generic firewall policies, like NF_ACCEPT. */
 249unsigned int
 250ip6t_do_table(struct sk_buff *skb,
 251              const struct nf_hook_state *state,
 252              struct xt_table *table)
 253{
 254        unsigned int hook = state->hook;
 255        static const char nulldevname[IFNAMSIZ] __attribute__((aligned(sizeof(long))));
 256        /* Initializing verdict to NF_DROP keeps gcc happy. */
 257        unsigned int verdict = NF_DROP;
 258        const char *indev, *outdev;
 259        const void *table_base;
 260        struct ip6t_entry *e, **jumpstack;
 261        unsigned int stackidx, cpu;
 262        const struct xt_table_info *private;
 263        struct xt_action_param acpar;
 264        unsigned int addend;
 265
 266        /* Initialization */
 267        stackidx = 0;
 268        indev = state->in ? state->in->name : nulldevname;
 269        outdev = state->out ? state->out->name : nulldevname;
 270        /* We handle fragments by dealing with the first fragment as
 271         * if it was a normal packet.  All other fragments are treated
 272         * normally, except that they will NEVER match rules that ask
 273         * things we don't know, ie. tcp syn flag or ports).  If the
 274         * rule is also a fragment-specific rule, non-fragments won't
 275         * match it. */
 276        acpar.hotdrop = false;
 277        acpar.state   = state;
 278
 279        WARN_ON(!(table->valid_hooks & (1 << hook)));
 280
 281        local_bh_disable();
 282        addend = xt_write_recseq_begin();
 283        private = rcu_access_pointer(table->private);
 284        cpu        = smp_processor_id();
 285        table_base = private->entries;
 286        jumpstack  = (struct ip6t_entry **)private->jumpstack[cpu];
 287
 288        /* Switch to alternate jumpstack if we're being invoked via TEE.
 289         * TEE issues XT_CONTINUE verdict on original skb so we must not
 290         * clobber the jumpstack.
 291         *
 292         * For recursion via REJECT or SYNPROXY the stack will be clobbered
 293         * but it is no problem since absolute verdict is issued by these.
 294         */
 295        if (static_key_false(&xt_tee_enabled))
 296                jumpstack += private->stacksize * __this_cpu_read(nf_skb_duplicated);
 297
 298        e = get_entry(table_base, private->hook_entry[hook]);
 299
 300        do {
 301                const struct xt_entry_target *t;
 302                const struct xt_entry_match *ematch;
 303                struct xt_counters *counter;
 304
 305                WARN_ON(!e);
 306                acpar.thoff = 0;
 307                if (!ip6_packet_match(skb, indev, outdev, &e->ipv6,
 308                    &acpar.thoff, &acpar.fragoff, &acpar.hotdrop)) {
 309 no_match:
 310                        e = ip6t_next_entry(e);
 311                        continue;
 312                }
 313
 314                xt_ematch_foreach(ematch, e) {
 315                        acpar.match     = ematch->u.kernel.match;
 316                        acpar.matchinfo = ematch->data;
 317                        if (!acpar.match->match(skb, &acpar))
 318                                goto no_match;
 319                }
 320
 321                counter = xt_get_this_cpu_counter(&e->counters);
 322                ADD_COUNTER(*counter, skb->len, 1);
 323
 324                t = ip6t_get_target_c(e);
 325                WARN_ON(!t->u.kernel.target);
 326
 327#if IS_ENABLED(CONFIG_NETFILTER_XT_TARGET_TRACE)
 328                /* The packet is traced: log it */
 329                if (unlikely(skb->nf_trace))
 330                        trace_packet(state->net, skb, hook, state->in,
 331                                     state->out, table->name, private, e);
 332#endif
 333                /* Standard target? */
 334                if (!t->u.kernel.target->target) {
 335                        int v;
 336
 337                        v = ((struct xt_standard_target *)t)->verdict;
 338                        if (v < 0) {
 339                                /* Pop from stack? */
 340                                if (v != XT_RETURN) {
 341                                        verdict = (unsigned int)(-v) - 1;
 342                                        break;
 343                                }
 344                                if (stackidx == 0)
 345                                        e = get_entry(table_base,
 346                                            private->underflow[hook]);
 347                                else
 348                                        e = ip6t_next_entry(jumpstack[--stackidx]);
 349                                continue;
 350                        }
 351                        if (table_base + v != ip6t_next_entry(e) &&
 352                            !(e->ipv6.flags & IP6T_F_GOTO)) {
 353                                if (unlikely(stackidx >= private->stacksize)) {
 354                                        verdict = NF_DROP;
 355                                        break;
 356                                }
 357                                jumpstack[stackidx++] = e;
 358                        }
 359
 360                        e = get_entry(table_base, v);
 361                        continue;
 362                }
 363
 364                acpar.target   = t->u.kernel.target;
 365                acpar.targinfo = t->data;
 366
 367                verdict = t->u.kernel.target->target(skb, &acpar);
 368                if (verdict == XT_CONTINUE)
 369                        e = ip6t_next_entry(e);
 370                else
 371                        /* Verdict */
 372                        break;
 373        } while (!acpar.hotdrop);
 374
 375        xt_write_recseq_end(addend);
 376        local_bh_enable();
 377
 378        if (acpar.hotdrop)
 379                return NF_DROP;
 380        else return verdict;
 381}
 382
 383/* Figures out from what hook each rule can be called: returns 0 if
 384   there are loops.  Puts hook bitmask in comefrom. */
 385static int
 386mark_source_chains(const struct xt_table_info *newinfo,
 387                   unsigned int valid_hooks, void *entry0,
 388                   unsigned int *offsets)
 389{
 390        unsigned int hook;
 391
 392        /* No recursion; use packet counter to save back ptrs (reset
 393           to 0 as we leave), and comefrom to save source hook bitmask */
 394        for (hook = 0; hook < NF_INET_NUMHOOKS; hook++) {
 395                unsigned int pos = newinfo->hook_entry[hook];
 396                struct ip6t_entry *e = entry0 + pos;
 397
 398                if (!(valid_hooks & (1 << hook)))
 399                        continue;
 400
 401                /* Set initial back pointer. */
 402                e->counters.pcnt = pos;
 403
 404                for (;;) {
 405                        const struct xt_standard_target *t
 406                                = (void *)ip6t_get_target_c(e);
 407                        int visited = e->comefrom & (1 << hook);
 408
 409                        if (e->comefrom & (1 << NF_INET_NUMHOOKS))
 410                                return 0;
 411
 412                        e->comefrom |= ((1 << hook) | (1 << NF_INET_NUMHOOKS));
 413
 414                        /* Unconditional return/END. */
 415                        if ((unconditional(e) &&
 416                             (strcmp(t->target.u.user.name,
 417                                     XT_STANDARD_TARGET) == 0) &&
 418                             t->verdict < 0) || visited) {
 419                                unsigned int oldpos, size;
 420
 421                                /* Return: backtrack through the last
 422                                   big jump. */
 423                                do {
 424                                        e->comefrom ^= (1<<NF_INET_NUMHOOKS);
 425                                        oldpos = pos;
 426                                        pos = e->counters.pcnt;
 427                                        e->counters.pcnt = 0;
 428
 429                                        /* We're at the start. */
 430                                        if (pos == oldpos)
 431                                                goto next;
 432
 433                                        e = entry0 + pos;
 434                                } while (oldpos == pos + e->next_offset);
 435
 436                                /* Move along one */
 437                                size = e->next_offset;
 438                                e = entry0 + pos + size;
 439                                if (pos + size >= newinfo->size)
 440                                        return 0;
 441                                e->counters.pcnt = pos;
 442                                pos += size;
 443                        } else {
 444                                int newpos = t->verdict;
 445
 446                                if (strcmp(t->target.u.user.name,
 447                                           XT_STANDARD_TARGET) == 0 &&
 448                                    newpos >= 0) {
 449                                        /* This a jump; chase it. */
 450                                        if (!xt_find_jump_offset(offsets, newpos,
 451                                                                 newinfo->number))
 452                                                return 0;
 453                                } else {
 454                                        /* ... this is a fallthru */
 455                                        newpos = pos + e->next_offset;
 456                                        if (newpos >= newinfo->size)
 457                                                return 0;
 458                                }
 459                                e = entry0 + newpos;
 460                                e->counters.pcnt = pos;
 461                                pos = newpos;
 462                        }
 463                }
 464next:           ;
 465        }
 466        return 1;
 467}
 468
 469static void cleanup_match(struct xt_entry_match *m, struct net *net)
 470{
 471        struct xt_mtdtor_param par;
 472
 473        par.net       = net;
 474        par.match     = m->u.kernel.match;
 475        par.matchinfo = m->data;
 476        par.family    = NFPROTO_IPV6;
 477        if (par.match->destroy != NULL)
 478                par.match->destroy(&par);
 479        module_put(par.match->me);
 480}
 481
 482static int check_match(struct xt_entry_match *m, struct xt_mtchk_param *par)
 483{
 484        const struct ip6t_ip6 *ipv6 = par->entryinfo;
 485
 486        par->match     = m->u.kernel.match;
 487        par->matchinfo = m->data;
 488
 489        return xt_check_match(par, m->u.match_size - sizeof(*m),
 490                              ipv6->proto, ipv6->invflags & IP6T_INV_PROTO);
 491}
 492
 493static int
 494find_check_match(struct xt_entry_match *m, struct xt_mtchk_param *par)
 495{
 496        struct xt_match *match;
 497        int ret;
 498
 499        match = xt_request_find_match(NFPROTO_IPV6, m->u.user.name,
 500                                      m->u.user.revision);
 501        if (IS_ERR(match))
 502                return PTR_ERR(match);
 503
 504        m->u.kernel.match = match;
 505
 506        ret = check_match(m, par);
 507        if (ret)
 508                goto err;
 509
 510        return 0;
 511err:
 512        module_put(m->u.kernel.match->me);
 513        return ret;
 514}
 515
 516static int check_target(struct ip6t_entry *e, struct net *net, const char *name)
 517{
 518        struct xt_entry_target *t = ip6t_get_target(e);
 519        struct xt_tgchk_param par = {
 520                .net       = net,
 521                .table     = name,
 522                .entryinfo = e,
 523                .target    = t->u.kernel.target,
 524                .targinfo  = t->data,
 525                .hook_mask = e->comefrom,
 526                .family    = NFPROTO_IPV6,
 527        };
 528
 529        return xt_check_target(&par, t->u.target_size - sizeof(*t),
 530                               e->ipv6.proto,
 531                               e->ipv6.invflags & IP6T_INV_PROTO);
 532}
 533
 534static int
 535find_check_entry(struct ip6t_entry *e, struct net *net, const char *name,
 536                 unsigned int size,
 537                 struct xt_percpu_counter_alloc_state *alloc_state)
 538{
 539        struct xt_entry_target *t;
 540        struct xt_target *target;
 541        int ret;
 542        unsigned int j;
 543        struct xt_mtchk_param mtpar;
 544        struct xt_entry_match *ematch;
 545
 546        if (!xt_percpu_counter_alloc(alloc_state, &e->counters))
 547                return -ENOMEM;
 548
 549        j = 0;
 550        memset(&mtpar, 0, sizeof(mtpar));
 551        mtpar.net       = net;
 552        mtpar.table     = name;
 553        mtpar.entryinfo = &e->ipv6;
 554        mtpar.hook_mask = e->comefrom;
 555        mtpar.family    = NFPROTO_IPV6;
 556        xt_ematch_foreach(ematch, e) {
 557                ret = find_check_match(ematch, &mtpar);
 558                if (ret != 0)
 559                        goto cleanup_matches;
 560                ++j;
 561        }
 562
 563        t = ip6t_get_target(e);
 564        target = xt_request_find_target(NFPROTO_IPV6, t->u.user.name,
 565                                        t->u.user.revision);
 566        if (IS_ERR(target)) {
 567                ret = PTR_ERR(target);
 568                goto cleanup_matches;
 569        }
 570        t->u.kernel.target = target;
 571
 572        ret = check_target(e, net, name);
 573        if (ret)
 574                goto err;
 575        return 0;
 576 err:
 577        module_put(t->u.kernel.target->me);
 578 cleanup_matches:
 579        xt_ematch_foreach(ematch, e) {
 580                if (j-- == 0)
 581                        break;
 582                cleanup_match(ematch, net);
 583        }
 584
 585        xt_percpu_counter_free(&e->counters);
 586
 587        return ret;
 588}
 589
 590static bool check_underflow(const struct ip6t_entry *e)
 591{
 592        const struct xt_entry_target *t;
 593        unsigned int verdict;
 594
 595        if (!unconditional(e))
 596                return false;
 597        t = ip6t_get_target_c(e);
 598        if (strcmp(t->u.user.name, XT_STANDARD_TARGET) != 0)
 599                return false;
 600        verdict = ((struct xt_standard_target *)t)->verdict;
 601        verdict = -verdict - 1;
 602        return verdict == NF_DROP || verdict == NF_ACCEPT;
 603}
 604
 605static int
 606check_entry_size_and_hooks(struct ip6t_entry *e,
 607                           struct xt_table_info *newinfo,
 608                           const unsigned char *base,
 609                           const unsigned char *limit,
 610                           const unsigned int *hook_entries,
 611                           const unsigned int *underflows,
 612                           unsigned int valid_hooks)
 613{
 614        unsigned int h;
 615        int err;
 616
 617        if ((unsigned long)e % __alignof__(struct ip6t_entry) != 0 ||
 618            (unsigned char *)e + sizeof(struct ip6t_entry) >= limit ||
 619            (unsigned char *)e + e->next_offset > limit)
 620                return -EINVAL;
 621
 622        if (e->next_offset
 623            < sizeof(struct ip6t_entry) + sizeof(struct xt_entry_target))
 624                return -EINVAL;
 625
 626        if (!ip6_checkentry(&e->ipv6))
 627                return -EINVAL;
 628
 629        err = xt_check_entry_offsets(e, e->elems, e->target_offset,
 630                                     e->next_offset);
 631        if (err)
 632                return err;
 633
 634        /* Check hooks & underflows */
 635        for (h = 0; h < NF_INET_NUMHOOKS; h++) {
 636                if (!(valid_hooks & (1 << h)))
 637                        continue;
 638                if ((unsigned char *)e - base == hook_entries[h])
 639                        newinfo->hook_entry[h] = hook_entries[h];
 640                if ((unsigned char *)e - base == underflows[h]) {
 641                        if (!check_underflow(e))
 642                                return -EINVAL;
 643
 644                        newinfo->underflow[h] = underflows[h];
 645                }
 646        }
 647
 648        /* Clear counters and comefrom */
 649        e->counters = ((struct xt_counters) { 0, 0 });
 650        e->comefrom = 0;
 651        return 0;
 652}
 653
 654static void cleanup_entry(struct ip6t_entry *e, struct net *net)
 655{
 656        struct xt_tgdtor_param par;
 657        struct xt_entry_target *t;
 658        struct xt_entry_match *ematch;
 659
 660        /* Cleanup all matches */
 661        xt_ematch_foreach(ematch, e)
 662                cleanup_match(ematch, net);
 663        t = ip6t_get_target(e);
 664
 665        par.net      = net;
 666        par.target   = t->u.kernel.target;
 667        par.targinfo = t->data;
 668        par.family   = NFPROTO_IPV6;
 669        if (par.target->destroy != NULL)
 670                par.target->destroy(&par);
 671        module_put(par.target->me);
 672        xt_percpu_counter_free(&e->counters);
 673}
 674
 675/* Checks and translates the user-supplied table segment (held in
 676   newinfo) */
 677static int
 678translate_table(struct net *net, struct xt_table_info *newinfo, void *entry0,
 679                const struct ip6t_replace *repl)
 680{
 681        struct xt_percpu_counter_alloc_state alloc_state = { 0 };
 682        struct ip6t_entry *iter;
 683        unsigned int *offsets;
 684        unsigned int i;
 685        int ret = 0;
 686
 687        newinfo->size = repl->size;
 688        newinfo->number = repl->num_entries;
 689
 690        /* Init all hooks to impossible value. */
 691        for (i = 0; i < NF_INET_NUMHOOKS; i++) {
 692                newinfo->hook_entry[i] = 0xFFFFFFFF;
 693                newinfo->underflow[i] = 0xFFFFFFFF;
 694        }
 695
 696        offsets = xt_alloc_entry_offsets(newinfo->number);
 697        if (!offsets)
 698                return -ENOMEM;
 699        i = 0;
 700        /* Walk through entries, checking offsets. */
 701        xt_entry_foreach(iter, entry0, newinfo->size) {
 702                ret = check_entry_size_and_hooks(iter, newinfo, entry0,
 703                                                 entry0 + repl->size,
 704                                                 repl->hook_entry,
 705                                                 repl->underflow,
 706                                                 repl->valid_hooks);
 707                if (ret != 0)
 708                        goto out_free;
 709                if (i < repl->num_entries)
 710                        offsets[i] = (void *)iter - entry0;
 711                ++i;
 712                if (strcmp(ip6t_get_target(iter)->u.user.name,
 713                    XT_ERROR_TARGET) == 0)
 714                        ++newinfo->stacksize;
 715        }
 716
 717        ret = -EINVAL;
 718        if (i != repl->num_entries)
 719                goto out_free;
 720
 721        ret = xt_check_table_hooks(newinfo, repl->valid_hooks);
 722        if (ret)
 723                goto out_free;
 724
 725        if (!mark_source_chains(newinfo, repl->valid_hooks, entry0, offsets)) {
 726                ret = -ELOOP;
 727                goto out_free;
 728        }
 729        kvfree(offsets);
 730
 731        /* Finally, each sanity check must pass */
 732        i = 0;
 733        xt_entry_foreach(iter, entry0, newinfo->size) {
 734                ret = find_check_entry(iter, net, repl->name, repl->size,
 735                                       &alloc_state);
 736                if (ret != 0)
 737                        break;
 738                ++i;
 739        }
 740
 741        if (ret != 0) {
 742                xt_entry_foreach(iter, entry0, newinfo->size) {
 743                        if (i-- == 0)
 744                                break;
 745                        cleanup_entry(iter, net);
 746                }
 747                return ret;
 748        }
 749
 750        return ret;
 751 out_free:
 752        kvfree(offsets);
 753        return ret;
 754}
 755
 756static void
 757get_counters(const struct xt_table_info *t,
 758             struct xt_counters counters[])
 759{
 760        struct ip6t_entry *iter;
 761        unsigned int cpu;
 762        unsigned int i;
 763
 764        for_each_possible_cpu(cpu) {
 765                seqcount_t *s = &per_cpu(xt_recseq, cpu);
 766
 767                i = 0;
 768                xt_entry_foreach(iter, t->entries, t->size) {
 769                        struct xt_counters *tmp;
 770                        u64 bcnt, pcnt;
 771                        unsigned int start;
 772
 773                        tmp = xt_get_per_cpu_counter(&iter->counters, cpu);
 774                        do {
 775                                start = read_seqcount_begin(s);
 776                                bcnt = tmp->bcnt;
 777                                pcnt = tmp->pcnt;
 778                        } while (read_seqcount_retry(s, start));
 779
 780                        ADD_COUNTER(counters[i], bcnt, pcnt);
 781                        ++i;
 782                        cond_resched();
 783                }
 784        }
 785}
 786
 787static void get_old_counters(const struct xt_table_info *t,
 788                             struct xt_counters counters[])
 789{
 790        struct ip6t_entry *iter;
 791        unsigned int cpu, i;
 792
 793        for_each_possible_cpu(cpu) {
 794                i = 0;
 795                xt_entry_foreach(iter, t->entries, t->size) {
 796                        const struct xt_counters *tmp;
 797
 798                        tmp = xt_get_per_cpu_counter(&iter->counters, cpu);
 799                        ADD_COUNTER(counters[i], tmp->bcnt, tmp->pcnt);
 800                        ++i;
 801                }
 802                cond_resched();
 803        }
 804}
 805
 806static struct xt_counters *alloc_counters(const struct xt_table *table)
 807{
 808        unsigned int countersize;
 809        struct xt_counters *counters;
 810        const struct xt_table_info *private = xt_table_get_private_protected(table);
 811
 812        /* We need atomic snapshot of counters: rest doesn't change
 813           (other than comefrom, which userspace doesn't care
 814           about). */
 815        countersize = sizeof(struct xt_counters) * private->number;
 816        counters = vzalloc(countersize);
 817
 818        if (counters == NULL)
 819                return ERR_PTR(-ENOMEM);
 820
 821        get_counters(private, counters);
 822
 823        return counters;
 824}
 825
 826static int
 827copy_entries_to_user(unsigned int total_size,
 828                     const struct xt_table *table,
 829                     void __user *userptr)
 830{
 831        unsigned int off, num;
 832        const struct ip6t_entry *e;
 833        struct xt_counters *counters;
 834        const struct xt_table_info *private = xt_table_get_private_protected(table);
 835        int ret = 0;
 836        const void *loc_cpu_entry;
 837
 838        counters = alloc_counters(table);
 839        if (IS_ERR(counters))
 840                return PTR_ERR(counters);
 841
 842        loc_cpu_entry = private->entries;
 843
 844        /* FIXME: use iterator macros --RR */
 845        /* ... then go back and fix counters and names */
 846        for (off = 0, num = 0; off < total_size; off += e->next_offset, num++){
 847                unsigned int i;
 848                const struct xt_entry_match *m;
 849                const struct xt_entry_target *t;
 850
 851                e = loc_cpu_entry + off;
 852                if (copy_to_user(userptr + off, e, sizeof(*e))) {
 853                        ret = -EFAULT;
 854                        goto free_counters;
 855                }
 856                if (copy_to_user(userptr + off
 857                                 + offsetof(struct ip6t_entry, counters),
 858                                 &counters[num],
 859                                 sizeof(counters[num])) != 0) {
 860                        ret = -EFAULT;
 861                        goto free_counters;
 862                }
 863
 864                for (i = sizeof(struct ip6t_entry);
 865                     i < e->target_offset;
 866                     i += m->u.match_size) {
 867                        m = (void *)e + i;
 868
 869                        if (xt_match_to_user(m, userptr + off + i)) {
 870                                ret = -EFAULT;
 871                                goto free_counters;
 872                        }
 873                }
 874
 875                t = ip6t_get_target_c(e);
 876                if (xt_target_to_user(t, userptr + off + e->target_offset)) {
 877                        ret = -EFAULT;
 878                        goto free_counters;
 879                }
 880        }
 881
 882 free_counters:
 883        vfree(counters);
 884        return ret;
 885}
 886
 887#ifdef CONFIG_COMPAT
 888static void compat_standard_from_user(void *dst, const void *src)
 889{
 890        int v = *(compat_int_t *)src;
 891
 892        if (v > 0)
 893                v += xt_compat_calc_jump(AF_INET6, v);
 894        memcpy(dst, &v, sizeof(v));
 895}
 896
 897static int compat_standard_to_user(void __user *dst, const void *src)
 898{
 899        compat_int_t cv = *(int *)src;
 900
 901        if (cv > 0)
 902                cv -= xt_compat_calc_jump(AF_INET6, cv);
 903        return copy_to_user(dst, &cv, sizeof(cv)) ? -EFAULT : 0;
 904}
 905
 906static int compat_calc_entry(const struct ip6t_entry *e,
 907                             const struct xt_table_info *info,
 908                             const void *base, struct xt_table_info *newinfo)
 909{
 910        const struct xt_entry_match *ematch;
 911        const struct xt_entry_target *t;
 912        unsigned int entry_offset;
 913        int off, i, ret;
 914
 915        off = sizeof(struct ip6t_entry) - sizeof(struct compat_ip6t_entry);
 916        entry_offset = (void *)e - base;
 917        xt_ematch_foreach(ematch, e)
 918                off += xt_compat_match_offset(ematch->u.kernel.match);
 919        t = ip6t_get_target_c(e);
 920        off += xt_compat_target_offset(t->u.kernel.target);
 921        newinfo->size -= off;
 922        ret = xt_compat_add_offset(AF_INET6, entry_offset, off);
 923        if (ret)
 924                return ret;
 925
 926        for (i = 0; i < NF_INET_NUMHOOKS; i++) {
 927                if (info->hook_entry[i] &&
 928                    (e < (struct ip6t_entry *)(base + info->hook_entry[i])))
 929                        newinfo->hook_entry[i] -= off;
 930                if (info->underflow[i] &&
 931                    (e < (struct ip6t_entry *)(base + info->underflow[i])))
 932                        newinfo->underflow[i] -= off;
 933        }
 934        return 0;
 935}
 936
 937static int compat_table_info(const struct xt_table_info *info,
 938                             struct xt_table_info *newinfo)
 939{
 940        struct ip6t_entry *iter;
 941        const void *loc_cpu_entry;
 942        int ret;
 943
 944        if (!newinfo || !info)
 945                return -EINVAL;
 946
 947        /* we dont care about newinfo->entries */
 948        memcpy(newinfo, info, offsetof(struct xt_table_info, entries));
 949        newinfo->initial_entries = 0;
 950        loc_cpu_entry = info->entries;
 951        ret = xt_compat_init_offsets(AF_INET6, info->number);
 952        if (ret)
 953                return ret;
 954        xt_entry_foreach(iter, loc_cpu_entry, info->size) {
 955                ret = compat_calc_entry(iter, info, loc_cpu_entry, newinfo);
 956                if (ret != 0)
 957                        return ret;
 958        }
 959        return 0;
 960}
 961#endif
 962
 963static int get_info(struct net *net, void __user *user, const int *len)
 964{
 965        char name[XT_TABLE_MAXNAMELEN];
 966        struct xt_table *t;
 967        int ret;
 968
 969        if (*len != sizeof(struct ip6t_getinfo))
 970                return -EINVAL;
 971
 972        if (copy_from_user(name, user, sizeof(name)) != 0)
 973                return -EFAULT;
 974
 975        name[XT_TABLE_MAXNAMELEN-1] = '\0';
 976#ifdef CONFIG_COMPAT
 977        if (in_compat_syscall())
 978                xt_compat_lock(AF_INET6);
 979#endif
 980        t = xt_request_find_table_lock(net, AF_INET6, name);
 981        if (!IS_ERR(t)) {
 982                struct ip6t_getinfo info;
 983                const struct xt_table_info *private = xt_table_get_private_protected(t);
 984#ifdef CONFIG_COMPAT
 985                struct xt_table_info tmp;
 986
 987                if (in_compat_syscall()) {
 988                        ret = compat_table_info(private, &tmp);
 989                        xt_compat_flush_offsets(AF_INET6);
 990                        private = &tmp;
 991                }
 992#endif
 993                memset(&info, 0, sizeof(info));
 994                info.valid_hooks = t->valid_hooks;
 995                memcpy(info.hook_entry, private->hook_entry,
 996                       sizeof(info.hook_entry));
 997                memcpy(info.underflow, private->underflow,
 998                       sizeof(info.underflow));
 999                info.num_entries = private->number;
1000                info.size = private->size;
1001                strcpy(info.name, name);
1002
1003                if (copy_to_user(user, &info, *len) != 0)
1004                        ret = -EFAULT;
1005                else
1006                        ret = 0;
1007
1008                xt_table_unlock(t);
1009                module_put(t->me);
1010        } else
1011                ret = PTR_ERR(t);
1012#ifdef CONFIG_COMPAT
1013        if (in_compat_syscall())
1014                xt_compat_unlock(AF_INET6);
1015#endif
1016        return ret;
1017}
1018
1019static int
1020get_entries(struct net *net, struct ip6t_get_entries __user *uptr,
1021            const int *len)
1022{
1023        int ret;
1024        struct ip6t_get_entries get;
1025        struct xt_table *t;
1026
1027        if (*len < sizeof(get))
1028                return -EINVAL;
1029        if (copy_from_user(&get, uptr, sizeof(get)) != 0)
1030                return -EFAULT;
1031        if (*len != sizeof(struct ip6t_get_entries) + get.size)
1032                return -EINVAL;
1033
1034        get.name[sizeof(get.name) - 1] = '\0';
1035
1036        t = xt_find_table_lock(net, AF_INET6, get.name);
1037        if (!IS_ERR(t)) {
1038                struct xt_table_info *private = xt_table_get_private_protected(t);
1039                if (get.size == private->size)
1040                        ret = copy_entries_to_user(private->size,
1041                                                   t, uptr->entrytable);
1042                else
1043                        ret = -EAGAIN;
1044
1045                module_put(t->me);
1046                xt_table_unlock(t);
1047        } else
1048                ret = PTR_ERR(t);
1049
1050        return ret;
1051}
1052
1053static int
1054__do_replace(struct net *net, const char *name, unsigned int valid_hooks,
1055             struct xt_table_info *newinfo, unsigned int num_counters,
1056             void __user *counters_ptr)
1057{
1058        int ret;
1059        struct xt_table *t;
1060        struct xt_table_info *oldinfo;
1061        struct xt_counters *counters;
1062        struct ip6t_entry *iter;
1063
1064        ret = 0;
1065        counters = xt_counters_alloc(num_counters);
1066        if (!counters) {
1067                ret = -ENOMEM;
1068                goto out;
1069        }
1070
1071        t = xt_request_find_table_lock(net, AF_INET6, name);
1072        if (IS_ERR(t)) {
1073                ret = PTR_ERR(t);
1074                goto free_newinfo_counters_untrans;
1075        }
1076
1077        /* You lied! */
1078        if (valid_hooks != t->valid_hooks) {
1079                ret = -EINVAL;
1080                goto put_module;
1081        }
1082
1083        oldinfo = xt_replace_table(t, num_counters, newinfo, &ret);
1084        if (!oldinfo)
1085                goto put_module;
1086
1087        /* Update module usage count based on number of rules */
1088        if ((oldinfo->number > oldinfo->initial_entries) ||
1089            (newinfo->number <= oldinfo->initial_entries))
1090                module_put(t->me);
1091        if ((oldinfo->number > oldinfo->initial_entries) &&
1092            (newinfo->number <= oldinfo->initial_entries))
1093                module_put(t->me);
1094
1095        xt_table_unlock(t);
1096
1097        get_old_counters(oldinfo, counters);
1098
1099        /* Decrease module usage counts and free resource */
1100        xt_entry_foreach(iter, oldinfo->entries, oldinfo->size)
1101                cleanup_entry(iter, net);
1102
1103        xt_free_table_info(oldinfo);
1104        if (copy_to_user(counters_ptr, counters,
1105                         sizeof(struct xt_counters) * num_counters) != 0) {
1106                /* Silent error, can't fail, new table is already in place */
1107                net_warn_ratelimited("ip6tables: counters copy to user failed while replacing table\n");
1108        }
1109        vfree(counters);
1110        return ret;
1111
1112 put_module:
1113        module_put(t->me);
1114        xt_table_unlock(t);
1115 free_newinfo_counters_untrans:
1116        vfree(counters);
1117 out:
1118        return ret;
1119}
1120
1121static int
1122do_replace(struct net *net, sockptr_t arg, unsigned int len)
1123{
1124        int ret;
1125        struct ip6t_replace tmp;
1126        struct xt_table_info *newinfo;
1127        void *loc_cpu_entry;
1128        struct ip6t_entry *iter;
1129
1130        if (copy_from_sockptr(&tmp, arg, sizeof(tmp)) != 0)
1131                return -EFAULT;
1132
1133        /* overflow check */
1134        if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
1135                return -ENOMEM;
1136        if (tmp.num_counters == 0)
1137                return -EINVAL;
1138
1139        tmp.name[sizeof(tmp.name)-1] = 0;
1140
1141        newinfo = xt_alloc_table_info(tmp.size);
1142        if (!newinfo)
1143                return -ENOMEM;
1144
1145        loc_cpu_entry = newinfo->entries;
1146        if (copy_from_sockptr_offset(loc_cpu_entry, arg, sizeof(tmp),
1147                        tmp.size) != 0) {
1148                ret = -EFAULT;
1149                goto free_newinfo;
1150        }
1151
1152        ret = translate_table(net, newinfo, loc_cpu_entry, &tmp);
1153        if (ret != 0)
1154                goto free_newinfo;
1155
1156        ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo,
1157                           tmp.num_counters, tmp.counters);
1158        if (ret)
1159                goto free_newinfo_untrans;
1160        return 0;
1161
1162 free_newinfo_untrans:
1163        xt_entry_foreach(iter, loc_cpu_entry, newinfo->size)
1164                cleanup_entry(iter, net);
1165 free_newinfo:
1166        xt_free_table_info(newinfo);
1167        return ret;
1168}
1169
1170static int
1171do_add_counters(struct net *net, sockptr_t arg, unsigned int len)
1172{
1173        unsigned int i;
1174        struct xt_counters_info tmp;
1175        struct xt_counters *paddc;
1176        struct xt_table *t;
1177        const struct xt_table_info *private;
1178        int ret = 0;
1179        struct ip6t_entry *iter;
1180        unsigned int addend;
1181
1182        paddc = xt_copy_counters(arg, len, &tmp);
1183        if (IS_ERR(paddc))
1184                return PTR_ERR(paddc);
1185        t = xt_find_table_lock(net, AF_INET6, tmp.name);
1186        if (IS_ERR(t)) {
1187                ret = PTR_ERR(t);
1188                goto free;
1189        }
1190
1191        local_bh_disable();
1192        private = xt_table_get_private_protected(t);
1193        if (private->number != tmp.num_counters) {
1194                ret = -EINVAL;
1195                goto unlock_up_free;
1196        }
1197
1198        i = 0;
1199        addend = xt_write_recseq_begin();
1200        xt_entry_foreach(iter, private->entries, private->size) {
1201                struct xt_counters *tmp;
1202
1203                tmp = xt_get_this_cpu_counter(&iter->counters);
1204                ADD_COUNTER(*tmp, paddc[i].bcnt, paddc[i].pcnt);
1205                ++i;
1206        }
1207        xt_write_recseq_end(addend);
1208 unlock_up_free:
1209        local_bh_enable();
1210        xt_table_unlock(t);
1211        module_put(t->me);
1212 free:
1213        vfree(paddc);
1214
1215        return ret;
1216}
1217
1218#ifdef CONFIG_COMPAT
1219struct compat_ip6t_replace {
1220        char                    name[XT_TABLE_MAXNAMELEN];
1221        u32                     valid_hooks;
1222        u32                     num_entries;
1223        u32                     size;
1224        u32                     hook_entry[NF_INET_NUMHOOKS];
1225        u32                     underflow[NF_INET_NUMHOOKS];
1226        u32                     num_counters;
1227        compat_uptr_t           counters;       /* struct xt_counters * */
1228        struct compat_ip6t_entry entries[];
1229};
1230
1231static int
1232compat_copy_entry_to_user(struct ip6t_entry *e, void __user **dstptr,
1233                          unsigned int *size, struct xt_counters *counters,
1234                          unsigned int i)
1235{
1236        struct xt_entry_target *t;
1237        struct compat_ip6t_entry __user *ce;
1238        u_int16_t target_offset, next_offset;
1239        compat_uint_t origsize;
1240        const struct xt_entry_match *ematch;
1241        int ret = 0;
1242
1243        origsize = *size;
1244        ce = *dstptr;
1245        if (copy_to_user(ce, e, sizeof(struct ip6t_entry)) != 0 ||
1246            copy_to_user(&ce->counters, &counters[i],
1247            sizeof(counters[i])) != 0)
1248                return -EFAULT;
1249
1250        *dstptr += sizeof(struct compat_ip6t_entry);
1251        *size -= sizeof(struct ip6t_entry) - sizeof(struct compat_ip6t_entry);
1252
1253        xt_ematch_foreach(ematch, e) {
1254                ret = xt_compat_match_to_user(ematch, dstptr, size);
1255                if (ret != 0)
1256                        return ret;
1257        }
1258        target_offset = e->target_offset - (origsize - *size);
1259        t = ip6t_get_target(e);
1260        ret = xt_compat_target_to_user(t, dstptr, size);
1261        if (ret)
1262                return ret;
1263        next_offset = e->next_offset - (origsize - *size);
1264        if (put_user(target_offset, &ce->target_offset) != 0 ||
1265            put_user(next_offset, &ce->next_offset) != 0)
1266                return -EFAULT;
1267        return 0;
1268}
1269
1270static int
1271compat_find_calc_match(struct xt_entry_match *m,
1272                       const struct ip6t_ip6 *ipv6,
1273                       int *size)
1274{
1275        struct xt_match *match;
1276
1277        match = xt_request_find_match(NFPROTO_IPV6, m->u.user.name,
1278                                      m->u.user.revision);
1279        if (IS_ERR(match))
1280                return PTR_ERR(match);
1281
1282        m->u.kernel.match = match;
1283        *size += xt_compat_match_offset(match);
1284        return 0;
1285}
1286
1287static void compat_release_entry(struct compat_ip6t_entry *e)
1288{
1289        struct xt_entry_target *t;
1290        struct xt_entry_match *ematch;
1291
1292        /* Cleanup all matches */
1293        xt_ematch_foreach(ematch, e)
1294                module_put(ematch->u.kernel.match->me);
1295        t = compat_ip6t_get_target(e);
1296        module_put(t->u.kernel.target->me);
1297}
1298
1299static int
1300check_compat_entry_size_and_hooks(struct compat_ip6t_entry *e,
1301                                  struct xt_table_info *newinfo,
1302                                  unsigned int *size,
1303                                  const unsigned char *base,
1304                                  const unsigned char *limit)
1305{
1306        struct xt_entry_match *ematch;
1307        struct xt_entry_target *t;
1308        struct xt_target *target;
1309        unsigned int entry_offset;
1310        unsigned int j;
1311        int ret, off;
1312
1313        if ((unsigned long)e % __alignof__(struct compat_ip6t_entry) != 0 ||
1314            (unsigned char *)e + sizeof(struct compat_ip6t_entry) >= limit ||
1315            (unsigned char *)e + e->next_offset > limit)
1316                return -EINVAL;
1317
1318        if (e->next_offset < sizeof(struct compat_ip6t_entry) +
1319                             sizeof(struct compat_xt_entry_target))
1320                return -EINVAL;
1321
1322        if (!ip6_checkentry(&e->ipv6))
1323                return -EINVAL;
1324
1325        ret = xt_compat_check_entry_offsets(e, e->elems,
1326                                            e->target_offset, e->next_offset);
1327        if (ret)
1328                return ret;
1329
1330        off = sizeof(struct ip6t_entry) - sizeof(struct compat_ip6t_entry);
1331        entry_offset = (void *)e - (void *)base;
1332        j = 0;
1333        xt_ematch_foreach(ematch, e) {
1334                ret = compat_find_calc_match(ematch, &e->ipv6, &off);
1335                if (ret != 0)
1336                        goto release_matches;
1337                ++j;
1338        }
1339
1340        t = compat_ip6t_get_target(e);
1341        target = xt_request_find_target(NFPROTO_IPV6, t->u.user.name,
1342                                        t->u.user.revision);
1343        if (IS_ERR(target)) {
1344                ret = PTR_ERR(target);
1345                goto release_matches;
1346        }
1347        t->u.kernel.target = target;
1348
1349        off += xt_compat_target_offset(target);
1350        *size += off;
1351        ret = xt_compat_add_offset(AF_INET6, entry_offset, off);
1352        if (ret)
1353                goto out;
1354
1355        return 0;
1356
1357out:
1358        module_put(t->u.kernel.target->me);
1359release_matches:
1360        xt_ematch_foreach(ematch, e) {
1361                if (j-- == 0)
1362                        break;
1363                module_put(ematch->u.kernel.match->me);
1364        }
1365        return ret;
1366}
1367
1368static void
1369compat_copy_entry_from_user(struct compat_ip6t_entry *e, void **dstptr,
1370                            unsigned int *size,
1371                            struct xt_table_info *newinfo, unsigned char *base)
1372{
1373        struct xt_entry_target *t;
1374        struct ip6t_entry *de;
1375        unsigned int origsize;
1376        int h;
1377        struct xt_entry_match *ematch;
1378
1379        origsize = *size;
1380        de = *dstptr;
1381        memcpy(de, e, sizeof(struct ip6t_entry));
1382        memcpy(&de->counters, &e->counters, sizeof(e->counters));
1383
1384        *dstptr += sizeof(struct ip6t_entry);
1385        *size += sizeof(struct ip6t_entry) - sizeof(struct compat_ip6t_entry);
1386
1387        xt_ematch_foreach(ematch, e)
1388                xt_compat_match_from_user(ematch, dstptr, size);
1389
1390        de->target_offset = e->target_offset - (origsize - *size);
1391        t = compat_ip6t_get_target(e);
1392        xt_compat_target_from_user(t, dstptr, size);
1393
1394        de->next_offset = e->next_offset - (origsize - *size);
1395        for (h = 0; h < NF_INET_NUMHOOKS; h++) {
1396                if ((unsigned char *)de - base < newinfo->hook_entry[h])
1397                        newinfo->hook_entry[h] -= origsize - *size;
1398                if ((unsigned char *)de - base < newinfo->underflow[h])
1399                        newinfo->underflow[h] -= origsize - *size;
1400        }
1401}
1402
1403static int
1404translate_compat_table(struct net *net,
1405                       struct xt_table_info **pinfo,
1406                       void **pentry0,
1407                       const struct compat_ip6t_replace *compatr)
1408{
1409        unsigned int i, j;
1410        struct xt_table_info *newinfo, *info;
1411        void *pos, *entry0, *entry1;
1412        struct compat_ip6t_entry *iter0;
1413        struct ip6t_replace repl;
1414        unsigned int size;
1415        int ret;
1416
1417        info = *pinfo;
1418        entry0 = *pentry0;
1419        size = compatr->size;
1420        info->number = compatr->num_entries;
1421
1422        j = 0;
1423        xt_compat_lock(AF_INET6);
1424        ret = xt_compat_init_offsets(AF_INET6, compatr->num_entries);
1425        if (ret)
1426                goto out_unlock;
1427        /* Walk through entries, checking offsets. */
1428        xt_entry_foreach(iter0, entry0, compatr->size) {
1429                ret = check_compat_entry_size_and_hooks(iter0, info, &size,
1430                                                        entry0,
1431                                                        entry0 + compatr->size);
1432                if (ret != 0)
1433                        goto out_unlock;
1434                ++j;
1435        }
1436
1437        ret = -EINVAL;
1438        if (j != compatr->num_entries)
1439                goto out_unlock;
1440
1441        ret = -ENOMEM;
1442        newinfo = xt_alloc_table_info(size);
1443        if (!newinfo)
1444                goto out_unlock;
1445
1446        newinfo->number = compatr->num_entries;
1447        for (i = 0; i < NF_INET_NUMHOOKS; i++) {
1448                newinfo->hook_entry[i] = compatr->hook_entry[i];
1449                newinfo->underflow[i] = compatr->underflow[i];
1450        }
1451        entry1 = newinfo->entries;
1452        pos = entry1;
1453        size = compatr->size;
1454        xt_entry_foreach(iter0, entry0, compatr->size)
1455                compat_copy_entry_from_user(iter0, &pos, &size,
1456                                            newinfo, entry1);
1457
1458        /* all module references in entry0 are now gone. */
1459        xt_compat_flush_offsets(AF_INET6);
1460        xt_compat_unlock(AF_INET6);
1461
1462        memcpy(&repl, compatr, sizeof(*compatr));
1463
1464        for (i = 0; i < NF_INET_NUMHOOKS; i++) {
1465                repl.hook_entry[i] = newinfo->hook_entry[i];
1466                repl.underflow[i] = newinfo->underflow[i];
1467        }
1468
1469        repl.num_counters = 0;
1470        repl.counters = NULL;
1471        repl.size = newinfo->size;
1472        ret = translate_table(net, newinfo, entry1, &repl);
1473        if (ret)
1474                goto free_newinfo;
1475
1476        *pinfo = newinfo;
1477        *pentry0 = entry1;
1478        xt_free_table_info(info);
1479        return 0;
1480
1481free_newinfo:
1482        xt_free_table_info(newinfo);
1483        return ret;
1484out_unlock:
1485        xt_compat_flush_offsets(AF_INET6);
1486        xt_compat_unlock(AF_INET6);
1487        xt_entry_foreach(iter0, entry0, compatr->size) {
1488                if (j-- == 0)
1489                        break;
1490                compat_release_entry(iter0);
1491        }
1492        return ret;
1493}
1494
1495static int
1496compat_do_replace(struct net *net, sockptr_t arg, unsigned int len)
1497{
1498        int ret;
1499        struct compat_ip6t_replace tmp;
1500        struct xt_table_info *newinfo;
1501        void *loc_cpu_entry;
1502        struct ip6t_entry *iter;
1503
1504        if (copy_from_sockptr(&tmp, arg, sizeof(tmp)) != 0)
1505                return -EFAULT;
1506
1507        /* overflow check */
1508        if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
1509                return -ENOMEM;
1510        if (tmp.num_counters == 0)
1511                return -EINVAL;
1512
1513        tmp.name[sizeof(tmp.name)-1] = 0;
1514
1515        newinfo = xt_alloc_table_info(tmp.size);
1516        if (!newinfo)
1517                return -ENOMEM;
1518
1519        loc_cpu_entry = newinfo->entries;
1520        if (copy_from_sockptr_offset(loc_cpu_entry, arg, sizeof(tmp),
1521                        tmp.size) != 0) {
1522                ret = -EFAULT;
1523                goto free_newinfo;
1524        }
1525
1526        ret = translate_compat_table(net, &newinfo, &loc_cpu_entry, &tmp);
1527        if (ret != 0)
1528                goto free_newinfo;
1529
1530        ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo,
1531                           tmp.num_counters, compat_ptr(tmp.counters));
1532        if (ret)
1533                goto free_newinfo_untrans;
1534        return 0;
1535
1536 free_newinfo_untrans:
1537        xt_entry_foreach(iter, loc_cpu_entry, newinfo->size)
1538                cleanup_entry(iter, net);
1539 free_newinfo:
1540        xt_free_table_info(newinfo);
1541        return ret;
1542}
1543
1544struct compat_ip6t_get_entries {
1545        char name[XT_TABLE_MAXNAMELEN];
1546        compat_uint_t size;
1547        struct compat_ip6t_entry entrytable[];
1548};
1549
1550static int
1551compat_copy_entries_to_user(unsigned int total_size, struct xt_table *table,
1552                            void __user *userptr)
1553{
1554        struct xt_counters *counters;
1555        const struct xt_table_info *private = xt_table_get_private_protected(table);
1556        void __user *pos;
1557        unsigned int size;
1558        int ret = 0;
1559        unsigned int i = 0;
1560        struct ip6t_entry *iter;
1561
1562        counters = alloc_counters(table);
1563        if (IS_ERR(counters))
1564                return PTR_ERR(counters);
1565
1566        pos = userptr;
1567        size = total_size;
1568        xt_entry_foreach(iter, private->entries, total_size) {
1569                ret = compat_copy_entry_to_user(iter, &pos,
1570                                                &size, counters, i++);
1571                if (ret != 0)
1572                        break;
1573        }
1574
1575        vfree(counters);
1576        return ret;
1577}
1578
1579static int
1580compat_get_entries(struct net *net, struct compat_ip6t_get_entries __user *uptr,
1581                   int *len)
1582{
1583        int ret;
1584        struct compat_ip6t_get_entries get;
1585        struct xt_table *t;
1586
1587        if (*len < sizeof(get))
1588                return -EINVAL;
1589
1590        if (copy_from_user(&get, uptr, sizeof(get)) != 0)
1591                return -EFAULT;
1592
1593        if (*len != sizeof(struct compat_ip6t_get_entries) + get.size)
1594                return -EINVAL;
1595
1596        get.name[sizeof(get.name) - 1] = '\0';
1597
1598        xt_compat_lock(AF_INET6);
1599        t = xt_find_table_lock(net, AF_INET6, get.name);
1600        if (!IS_ERR(t)) {
1601                const struct xt_table_info *private = t->private;
1602                struct xt_table_info info;
1603                ret = compat_table_info(private, &info);
1604                if (!ret && get.size == info.size)
1605                        ret = compat_copy_entries_to_user(private->size,
1606                                                          t, uptr->entrytable);
1607                else if (!ret)
1608                        ret = -EAGAIN;
1609
1610                xt_compat_flush_offsets(AF_INET6);
1611                module_put(t->me);
1612                xt_table_unlock(t);
1613        } else
1614                ret = PTR_ERR(t);
1615
1616        xt_compat_unlock(AF_INET6);
1617        return ret;
1618}
1619#endif
1620
1621static int
1622do_ip6t_set_ctl(struct sock *sk, int cmd, sockptr_t arg, unsigned int len)
1623{
1624        int ret;
1625
1626        if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1627                return -EPERM;
1628
1629        switch (cmd) {
1630        case IP6T_SO_SET_REPLACE:
1631#ifdef CONFIG_COMPAT
1632                if (in_compat_syscall())
1633                        ret = compat_do_replace(sock_net(sk), arg, len);
1634                else
1635#endif
1636                        ret = do_replace(sock_net(sk), arg, len);
1637                break;
1638
1639        case IP6T_SO_SET_ADD_COUNTERS:
1640                ret = do_add_counters(sock_net(sk), arg, len);
1641                break;
1642
1643        default:
1644                ret = -EINVAL;
1645        }
1646
1647        return ret;
1648}
1649
1650static int
1651do_ip6t_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
1652{
1653        int ret;
1654
1655        if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
1656                return -EPERM;
1657
1658        switch (cmd) {
1659        case IP6T_SO_GET_INFO:
1660                ret = get_info(sock_net(sk), user, len);
1661                break;
1662
1663        case IP6T_SO_GET_ENTRIES:
1664#ifdef CONFIG_COMPAT
1665                if (in_compat_syscall())
1666                        ret = compat_get_entries(sock_net(sk), user, len);
1667                else
1668#endif
1669                        ret = get_entries(sock_net(sk), user, len);
1670                break;
1671
1672        case IP6T_SO_GET_REVISION_MATCH:
1673        case IP6T_SO_GET_REVISION_TARGET: {
1674                struct xt_get_revision rev;
1675                int target;
1676
1677                if (*len != sizeof(rev)) {
1678                        ret = -EINVAL;
1679                        break;
1680                }
1681                if (copy_from_user(&rev, user, sizeof(rev)) != 0) {
1682                        ret = -EFAULT;
1683                        break;
1684                }
1685                rev.name[sizeof(rev.name)-1] = 0;
1686
1687                if (cmd == IP6T_SO_GET_REVISION_TARGET)
1688                        target = 1;
1689                else
1690                        target = 0;
1691
1692                try_then_request_module(xt_find_revision(AF_INET6, rev.name,
1693                                                         rev.revision,
1694                                                         target, &ret),
1695                                        "ip6t_%s", rev.name);
1696                break;
1697        }
1698
1699        default:
1700                ret = -EINVAL;
1701        }
1702
1703        return ret;
1704}
1705
1706static void __ip6t_unregister_table(struct net *net, struct xt_table *table)
1707{
1708        struct xt_table_info *private;
1709        void *loc_cpu_entry;
1710        struct module *table_owner = table->me;
1711        struct ip6t_entry *iter;
1712
1713        private = xt_unregister_table(table);
1714
1715        /* Decrease module usage counts and free resources */
1716        loc_cpu_entry = private->entries;
1717        xt_entry_foreach(iter, loc_cpu_entry, private->size)
1718                cleanup_entry(iter, net);
1719        if (private->number > private->initial_entries)
1720                module_put(table_owner);
1721        xt_free_table_info(private);
1722}
1723
1724int ip6t_register_table(struct net *net, const struct xt_table *table,
1725                        const struct ip6t_replace *repl,
1726                        const struct nf_hook_ops *ops,
1727                        struct xt_table **res)
1728{
1729        int ret;
1730        struct xt_table_info *newinfo;
1731        struct xt_table_info bootstrap = {0};
1732        void *loc_cpu_entry;
1733        struct xt_table *new_table;
1734
1735        newinfo = xt_alloc_table_info(repl->size);
1736        if (!newinfo)
1737                return -ENOMEM;
1738
1739        loc_cpu_entry = newinfo->entries;
1740        memcpy(loc_cpu_entry, repl->entries, repl->size);
1741
1742        ret = translate_table(net, newinfo, loc_cpu_entry, repl);
1743        if (ret != 0)
1744                goto out_free;
1745
1746        new_table = xt_register_table(net, table, &bootstrap, newinfo);
1747        if (IS_ERR(new_table)) {
1748                ret = PTR_ERR(new_table);
1749                goto out_free;
1750        }
1751
1752        /* set res now, will see skbs right after nf_register_net_hooks */
1753        WRITE_ONCE(*res, new_table);
1754        if (!ops)
1755                return 0;
1756
1757        ret = nf_register_net_hooks(net, ops, hweight32(table->valid_hooks));
1758        if (ret != 0) {
1759                __ip6t_unregister_table(net, new_table);
1760                *res = NULL;
1761        }
1762
1763        return ret;
1764
1765out_free:
1766        xt_free_table_info(newinfo);
1767        return ret;
1768}
1769
1770void ip6t_unregister_table_pre_exit(struct net *net, struct xt_table *table,
1771                                    const struct nf_hook_ops *ops)
1772{
1773        nf_unregister_net_hooks(net, ops, hweight32(table->valid_hooks));
1774}
1775
1776void ip6t_unregister_table_exit(struct net *net, struct xt_table *table)
1777{
1778        __ip6t_unregister_table(net, table);
1779}
1780
1781void ip6t_unregister_table(struct net *net, struct xt_table *table,
1782                           const struct nf_hook_ops *ops)
1783{
1784        if (ops)
1785                ip6t_unregister_table_pre_exit(net, table, ops);
1786        __ip6t_unregister_table(net, table);
1787}
1788
1789/* Returns 1 if the type and code is matched by the range, 0 otherwise */
1790static inline bool
1791icmp6_type_code_match(u_int8_t test_type, u_int8_t min_code, u_int8_t max_code,
1792                     u_int8_t type, u_int8_t code,
1793                     bool invert)
1794{
1795        return (type == test_type && code >= min_code && code <= max_code)
1796                ^ invert;
1797}
1798
1799static bool
1800icmp6_match(const struct sk_buff *skb, struct xt_action_param *par)
1801{
1802        const struct icmp6hdr *ic;
1803        struct icmp6hdr _icmph;
1804        const struct ip6t_icmp *icmpinfo = par->matchinfo;
1805
1806        /* Must not be a fragment. */
1807        if (par->fragoff != 0)
1808                return false;
1809
1810        ic = skb_header_pointer(skb, par->thoff, sizeof(_icmph), &_icmph);
1811        if (ic == NULL) {
1812                /* We've been asked to examine this packet, and we
1813                 * can't.  Hence, no choice but to drop.
1814                 */
1815                par->hotdrop = true;
1816                return false;
1817        }
1818
1819        return icmp6_type_code_match(icmpinfo->type,
1820                                     icmpinfo->code[0],
1821                                     icmpinfo->code[1],
1822                                     ic->icmp6_type, ic->icmp6_code,
1823                                     !!(icmpinfo->invflags&IP6T_ICMP_INV));
1824}
1825
1826/* Called when user tries to insert an entry of this type. */
1827static int icmp6_checkentry(const struct xt_mtchk_param *par)
1828{
1829        const struct ip6t_icmp *icmpinfo = par->matchinfo;
1830
1831        /* Must specify no unknown invflags */
1832        return (icmpinfo->invflags & ~IP6T_ICMP_INV) ? -EINVAL : 0;
1833}
1834
1835/* The built-in targets: standard (NULL) and error. */
1836static struct xt_target ip6t_builtin_tg[] __read_mostly = {
1837        {
1838                .name             = XT_STANDARD_TARGET,
1839                .targetsize       = sizeof(int),
1840                .family           = NFPROTO_IPV6,
1841#ifdef CONFIG_COMPAT
1842                .compatsize       = sizeof(compat_int_t),
1843                .compat_from_user = compat_standard_from_user,
1844                .compat_to_user   = compat_standard_to_user,
1845#endif
1846        },
1847        {
1848                .name             = XT_ERROR_TARGET,
1849                .target           = ip6t_error,
1850                .targetsize       = XT_FUNCTION_MAXNAMELEN,
1851                .family           = NFPROTO_IPV6,
1852        },
1853};
1854
1855static struct nf_sockopt_ops ip6t_sockopts = {
1856        .pf             = PF_INET6,
1857        .set_optmin     = IP6T_BASE_CTL,
1858        .set_optmax     = IP6T_SO_SET_MAX+1,
1859        .set            = do_ip6t_set_ctl,
1860        .get_optmin     = IP6T_BASE_CTL,
1861        .get_optmax     = IP6T_SO_GET_MAX+1,
1862        .get            = do_ip6t_get_ctl,
1863        .owner          = THIS_MODULE,
1864};
1865
1866static struct xt_match ip6t_builtin_mt[] __read_mostly = {
1867        {
1868                .name       = "icmp6",
1869                .match      = icmp6_match,
1870                .matchsize  = sizeof(struct ip6t_icmp),
1871                .checkentry = icmp6_checkentry,
1872                .proto      = IPPROTO_ICMPV6,
1873                .family     = NFPROTO_IPV6,
1874                .me         = THIS_MODULE,
1875        },
1876};
1877
1878static int __net_init ip6_tables_net_init(struct net *net)
1879{
1880        return xt_proto_init(net, NFPROTO_IPV6);
1881}
1882
1883static void __net_exit ip6_tables_net_exit(struct net *net)
1884{
1885        xt_proto_fini(net, NFPROTO_IPV6);
1886}
1887
1888static struct pernet_operations ip6_tables_net_ops = {
1889        .init = ip6_tables_net_init,
1890        .exit = ip6_tables_net_exit,
1891};
1892
1893static int __init ip6_tables_init(void)
1894{
1895        int ret;
1896
1897        ret = register_pernet_subsys(&ip6_tables_net_ops);
1898        if (ret < 0)
1899                goto err1;
1900
1901        /* No one else will be downing sem now, so we won't sleep */
1902        ret = xt_register_targets(ip6t_builtin_tg, ARRAY_SIZE(ip6t_builtin_tg));
1903        if (ret < 0)
1904                goto err2;
1905        ret = xt_register_matches(ip6t_builtin_mt, ARRAY_SIZE(ip6t_builtin_mt));
1906        if (ret < 0)
1907                goto err4;
1908
1909        /* Register setsockopt */
1910        ret = nf_register_sockopt(&ip6t_sockopts);
1911        if (ret < 0)
1912                goto err5;
1913
1914        return 0;
1915
1916err5:
1917        xt_unregister_matches(ip6t_builtin_mt, ARRAY_SIZE(ip6t_builtin_mt));
1918err4:
1919        xt_unregister_targets(ip6t_builtin_tg, ARRAY_SIZE(ip6t_builtin_tg));
1920err2:
1921        unregister_pernet_subsys(&ip6_tables_net_ops);
1922err1:
1923        return ret;
1924}
1925
1926static void __exit ip6_tables_fini(void)
1927{
1928        nf_unregister_sockopt(&ip6t_sockopts);
1929
1930        xt_unregister_matches(ip6t_builtin_mt, ARRAY_SIZE(ip6t_builtin_mt));
1931        xt_unregister_targets(ip6t_builtin_tg, ARRAY_SIZE(ip6t_builtin_tg));
1932        unregister_pernet_subsys(&ip6_tables_net_ops);
1933}
1934
1935EXPORT_SYMBOL(ip6t_register_table);
1936EXPORT_SYMBOL(ip6t_unregister_table);
1937EXPORT_SYMBOL(ip6t_unregister_table_pre_exit);
1938EXPORT_SYMBOL(ip6t_unregister_table_exit);
1939EXPORT_SYMBOL(ip6t_do_table);
1940
1941module_init(ip6_tables_init);
1942module_exit(ip6_tables_fini);
1943