linux/net/ipv4/netfilter/arp_tables.c
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   1/*
   2 * Packet matching code for ARP packets.
   3 *
   4 * Based heavily, if not almost entirely, upon ip_tables.c framework.
   5 *
   6 * Some ARP specific bits are:
   7 *
   8 * Copyright (C) 2002 David S. Miller (davem@redhat.com)
   9 *
  10 */
  11#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  12#include <linux/kernel.h>
  13#include <linux/skbuff.h>
  14#include <linux/netdevice.h>
  15#include <linux/capability.h>
  16#include <linux/if_arp.h>
  17#include <linux/kmod.h>
  18#include <linux/vmalloc.h>
  19#include <linux/proc_fs.h>
  20#include <linux/module.h>
  21#include <linux/init.h>
  22#include <linux/mutex.h>
  23#include <linux/err.h>
  24#include <net/compat.h>
  25#include <net/sock.h>
  26#include <asm/uaccess.h>
  27
  28#include <linux/netfilter/x_tables.h>
  29#include <linux/netfilter_arp/arp_tables.h>
  30#include "../../netfilter/xt_repldata.h"
  31
  32MODULE_LICENSE("GPL");
  33MODULE_AUTHOR("David S. Miller <davem@redhat.com>");
  34MODULE_DESCRIPTION("arptables core");
  35
  36/*#define DEBUG_ARP_TABLES*/
  37/*#define DEBUG_ARP_TABLES_USER*/
  38
  39#ifdef DEBUG_ARP_TABLES
  40#define dprintf(format, args...)  printk(format , ## args)
  41#else
  42#define dprintf(format, args...)
  43#endif
  44
  45#ifdef DEBUG_ARP_TABLES_USER
  46#define duprintf(format, args...) printk(format , ## args)
  47#else
  48#define duprintf(format, args...)
  49#endif
  50
  51#ifdef CONFIG_NETFILTER_DEBUG
  52#define ARP_NF_ASSERT(x)        WARN_ON(!(x))
  53#else
  54#define ARP_NF_ASSERT(x)
  55#endif
  56
  57void *arpt_alloc_initial_table(const struct xt_table *info)
  58{
  59        return xt_alloc_initial_table(arpt, ARPT);
  60}
  61EXPORT_SYMBOL_GPL(arpt_alloc_initial_table);
  62
  63static inline int arp_devaddr_compare(const struct arpt_devaddr_info *ap,
  64                                      const char *hdr_addr, int len)
  65{
  66        int i, ret;
  67
  68        if (len > ARPT_DEV_ADDR_LEN_MAX)
  69                len = ARPT_DEV_ADDR_LEN_MAX;
  70
  71        ret = 0;
  72        for (i = 0; i < len; i++)
  73                ret |= (hdr_addr[i] ^ ap->addr[i]) & ap->mask[i];
  74
  75        return ret != 0;
  76}
  77
  78/*
  79 * Unfortunatly, _b and _mask are not aligned to an int (or long int)
  80 * Some arches dont care, unrolling the loop is a win on them.
  81 * For other arches, we only have a 16bit alignement.
  82 */
  83static unsigned long ifname_compare(const char *_a, const char *_b, const char *_mask)
  84{
  85#ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
  86        unsigned long ret = ifname_compare_aligned(_a, _b, _mask);
  87#else
  88        unsigned long ret = 0;
  89        const u16 *a = (const u16 *)_a;
  90        const u16 *b = (const u16 *)_b;
  91        const u16 *mask = (const u16 *)_mask;
  92        int i;
  93
  94        for (i = 0; i < IFNAMSIZ/sizeof(u16); i++)
  95                ret |= (a[i] ^ b[i]) & mask[i];
  96#endif
  97        return ret;
  98}
  99
 100/* Returns whether packet matches rule or not. */
 101static inline int arp_packet_match(const struct arphdr *arphdr,
 102                                   struct net_device *dev,
 103                                   const char *indev,
 104                                   const char *outdev,
 105                                   const struct arpt_arp *arpinfo)
 106{
 107        const char *arpptr = (char *)(arphdr + 1);
 108        const char *src_devaddr, *tgt_devaddr;
 109        __be32 src_ipaddr, tgt_ipaddr;
 110        long ret;
 111
 112#define FWINV(bool, invflg) ((bool) ^ !!(arpinfo->invflags & (invflg)))
 113
 114        if (FWINV((arphdr->ar_op & arpinfo->arpop_mask) != arpinfo->arpop,
 115                  ARPT_INV_ARPOP)) {
 116                dprintf("ARP operation field mismatch.\n");
 117                dprintf("ar_op: %04x info->arpop: %04x info->arpop_mask: %04x\n",
 118                        arphdr->ar_op, arpinfo->arpop, arpinfo->arpop_mask);
 119                return 0;
 120        }
 121
 122        if (FWINV((arphdr->ar_hrd & arpinfo->arhrd_mask) != arpinfo->arhrd,
 123                  ARPT_INV_ARPHRD)) {
 124                dprintf("ARP hardware address format mismatch.\n");
 125                dprintf("ar_hrd: %04x info->arhrd: %04x info->arhrd_mask: %04x\n",
 126                        arphdr->ar_hrd, arpinfo->arhrd, arpinfo->arhrd_mask);
 127                return 0;
 128        }
 129
 130        if (FWINV((arphdr->ar_pro & arpinfo->arpro_mask) != arpinfo->arpro,
 131                  ARPT_INV_ARPPRO)) {
 132                dprintf("ARP protocol address format mismatch.\n");
 133                dprintf("ar_pro: %04x info->arpro: %04x info->arpro_mask: %04x\n",
 134                        arphdr->ar_pro, arpinfo->arpro, arpinfo->arpro_mask);
 135                return 0;
 136        }
 137
 138        if (FWINV((arphdr->ar_hln & arpinfo->arhln_mask) != arpinfo->arhln,
 139                  ARPT_INV_ARPHLN)) {
 140                dprintf("ARP hardware address length mismatch.\n");
 141                dprintf("ar_hln: %02x info->arhln: %02x info->arhln_mask: %02x\n",
 142                        arphdr->ar_hln, arpinfo->arhln, arpinfo->arhln_mask);
 143                return 0;
 144        }
 145
 146        src_devaddr = arpptr;
 147        arpptr += dev->addr_len;
 148        memcpy(&src_ipaddr, arpptr, sizeof(u32));
 149        arpptr += sizeof(u32);
 150        tgt_devaddr = arpptr;
 151        arpptr += dev->addr_len;
 152        memcpy(&tgt_ipaddr, arpptr, sizeof(u32));
 153
 154        if (FWINV(arp_devaddr_compare(&arpinfo->src_devaddr, src_devaddr, dev->addr_len),
 155                  ARPT_INV_SRCDEVADDR) ||
 156            FWINV(arp_devaddr_compare(&arpinfo->tgt_devaddr, tgt_devaddr, dev->addr_len),
 157                  ARPT_INV_TGTDEVADDR)) {
 158                dprintf("Source or target device address mismatch.\n");
 159
 160                return 0;
 161        }
 162
 163        if (FWINV((src_ipaddr & arpinfo->smsk.s_addr) != arpinfo->src.s_addr,
 164                  ARPT_INV_SRCIP) ||
 165            FWINV(((tgt_ipaddr & arpinfo->tmsk.s_addr) != arpinfo->tgt.s_addr),
 166                  ARPT_INV_TGTIP)) {
 167                dprintf("Source or target IP address mismatch.\n");
 168
 169                dprintf("SRC: %pI4. Mask: %pI4. Target: %pI4.%s\n",
 170                        &src_ipaddr,
 171                        &arpinfo->smsk.s_addr,
 172                        &arpinfo->src.s_addr,
 173                        arpinfo->invflags & ARPT_INV_SRCIP ? " (INV)" : "");
 174                dprintf("TGT: %pI4 Mask: %pI4 Target: %pI4.%s\n",
 175                        &tgt_ipaddr,
 176                        &arpinfo->tmsk.s_addr,
 177                        &arpinfo->tgt.s_addr,
 178                        arpinfo->invflags & ARPT_INV_TGTIP ? " (INV)" : "");
 179                return 0;
 180        }
 181
 182        /* Look for ifname matches.  */
 183        ret = ifname_compare(indev, arpinfo->iniface, arpinfo->iniface_mask);
 184
 185        if (FWINV(ret != 0, ARPT_INV_VIA_IN)) {
 186                dprintf("VIA in mismatch (%s vs %s).%s\n",
 187                        indev, arpinfo->iniface,
 188                        arpinfo->invflags&ARPT_INV_VIA_IN ?" (INV)":"");
 189                return 0;
 190        }
 191
 192        ret = ifname_compare(outdev, arpinfo->outiface, arpinfo->outiface_mask);
 193
 194        if (FWINV(ret != 0, ARPT_INV_VIA_OUT)) {
 195                dprintf("VIA out mismatch (%s vs %s).%s\n",
 196                        outdev, arpinfo->outiface,
 197                        arpinfo->invflags&ARPT_INV_VIA_OUT ?" (INV)":"");
 198                return 0;
 199        }
 200
 201        return 1;
 202#undef FWINV
 203}
 204
 205static inline int arp_checkentry(const struct arpt_arp *arp)
 206{
 207        if (arp->flags & ~ARPT_F_MASK) {
 208                duprintf("Unknown flag bits set: %08X\n",
 209                         arp->flags & ~ARPT_F_MASK);
 210                return 0;
 211        }
 212        if (arp->invflags & ~ARPT_INV_MASK) {
 213                duprintf("Unknown invflag bits set: %08X\n",
 214                         arp->invflags & ~ARPT_INV_MASK);
 215                return 0;
 216        }
 217
 218        return 1;
 219}
 220
 221static unsigned int
 222arpt_error(struct sk_buff *skb, const struct xt_action_param *par)
 223{
 224        if (net_ratelimit())
 225                pr_err("arp_tables: error: '%s'\n",
 226                       (const char *)par->targinfo);
 227
 228        return NF_DROP;
 229}
 230
 231static inline const struct xt_entry_target *
 232arpt_get_target_c(const struct arpt_entry *e)
 233{
 234        return arpt_get_target((struct arpt_entry *)e);
 235}
 236
 237static inline struct arpt_entry *
 238get_entry(const void *base, unsigned int offset)
 239{
 240        return (struct arpt_entry *)(base + offset);
 241}
 242
 243static inline __pure
 244struct arpt_entry *arpt_next_entry(const struct arpt_entry *entry)
 245{
 246        return (void *)entry + entry->next_offset;
 247}
 248
 249unsigned int arpt_do_table(struct sk_buff *skb,
 250                           unsigned int hook,
 251                           const struct net_device *in,
 252                           const struct net_device *out,
 253                           struct xt_table *table)
 254{
 255        static const char nulldevname[IFNAMSIZ] __attribute__((aligned(sizeof(long))));
 256        unsigned int verdict = NF_DROP;
 257        const struct arphdr *arp;
 258        struct arpt_entry *e, *back;
 259        const char *indev, *outdev;
 260        void *table_base;
 261        const struct xt_table_info *private;
 262        struct xt_action_param acpar;
 263
 264        if (!pskb_may_pull(skb, arp_hdr_len(skb->dev)))
 265                return NF_DROP;
 266
 267        indev = in ? in->name : nulldevname;
 268        outdev = out ? out->name : nulldevname;
 269
 270        xt_info_rdlock_bh();
 271        private = table->private;
 272        table_base = private->entries[smp_processor_id()];
 273
 274        e = get_entry(table_base, private->hook_entry[hook]);
 275        back = get_entry(table_base, private->underflow[hook]);
 276
 277        acpar.in      = in;
 278        acpar.out     = out;
 279        acpar.hooknum = hook;
 280        acpar.family  = NFPROTO_ARP;
 281        acpar.hotdrop = false;
 282
 283        arp = arp_hdr(skb);
 284        do {
 285                const struct xt_entry_target *t;
 286
 287                if (!arp_packet_match(arp, skb->dev, indev, outdev, &e->arp)) {
 288                        e = arpt_next_entry(e);
 289                        continue;
 290                }
 291
 292                ADD_COUNTER(e->counters, arp_hdr_len(skb->dev), 1);
 293
 294                t = arpt_get_target_c(e);
 295
 296                /* Standard target? */
 297                if (!t->u.kernel.target->target) {
 298                        int v;
 299
 300                        v = ((struct xt_standard_target *)t)->verdict;
 301                        if (v < 0) {
 302                                /* Pop from stack? */
 303                                if (v != XT_RETURN) {
 304                                        verdict = (unsigned)(-v) - 1;
 305                                        break;
 306                                }
 307                                e = back;
 308                                back = get_entry(table_base, back->comefrom);
 309                                continue;
 310                        }
 311                        if (table_base + v
 312                            != arpt_next_entry(e)) {
 313                                /* Save old back ptr in next entry */
 314                                struct arpt_entry *next = arpt_next_entry(e);
 315                                next->comefrom = (void *)back - table_base;
 316
 317                                /* set back pointer to next entry */
 318                                back = next;
 319                        }
 320
 321                        e = get_entry(table_base, v);
 322                        continue;
 323                }
 324
 325                /* Targets which reenter must return
 326                 * abs. verdicts
 327                 */
 328                acpar.target   = t->u.kernel.target;
 329                acpar.targinfo = t->data;
 330                verdict = t->u.kernel.target->target(skb, &acpar);
 331
 332                /* Target might have changed stuff. */
 333                arp = arp_hdr(skb);
 334
 335                if (verdict == XT_CONTINUE)
 336                        e = arpt_next_entry(e);
 337                else
 338                        /* Verdict */
 339                        break;
 340        } while (!acpar.hotdrop);
 341        xt_info_rdunlock_bh();
 342
 343        if (acpar.hotdrop)
 344                return NF_DROP;
 345        else
 346                return verdict;
 347}
 348
 349/* All zeroes == unconditional rule. */
 350static inline bool unconditional(const struct arpt_arp *arp)
 351{
 352        static const struct arpt_arp uncond;
 353
 354        return memcmp(arp, &uncond, sizeof(uncond)) == 0;
 355}
 356
 357/* Figures out from what hook each rule can be called: returns 0 if
 358 * there are loops.  Puts hook bitmask in comefrom.
 359 */
 360static int mark_source_chains(const struct xt_table_info *newinfo,
 361                              unsigned int valid_hooks, void *entry0)
 362{
 363        unsigned int hook;
 364
 365        /* No recursion; use packet counter to save back ptrs (reset
 366         * to 0 as we leave), and comefrom to save source hook bitmask.
 367         */
 368        for (hook = 0; hook < NF_ARP_NUMHOOKS; hook++) {
 369                unsigned int pos = newinfo->hook_entry[hook];
 370                struct arpt_entry *e
 371                        = (struct arpt_entry *)(entry0 + pos);
 372
 373                if (!(valid_hooks & (1 << hook)))
 374                        continue;
 375
 376                /* Set initial back pointer. */
 377                e->counters.pcnt = pos;
 378
 379                for (;;) {
 380                        const struct xt_standard_target *t
 381                                = (void *)arpt_get_target_c(e);
 382                        int visited = e->comefrom & (1 << hook);
 383
 384                        if (e->comefrom & (1 << NF_ARP_NUMHOOKS)) {
 385                                pr_notice("arptables: loop hook %u pos %u %08X.\n",
 386                                       hook, pos, e->comefrom);
 387                                return 0;
 388                        }
 389                        e->comefrom
 390                                |= ((1 << hook) | (1 << NF_ARP_NUMHOOKS));
 391
 392                        /* Unconditional return/END. */
 393                        if ((e->target_offset == sizeof(struct arpt_entry) &&
 394                             (strcmp(t->target.u.user.name,
 395                                     XT_STANDARD_TARGET) == 0) &&
 396                             t->verdict < 0 && unconditional(&e->arp)) ||
 397                            visited) {
 398                                unsigned int oldpos, size;
 399
 400                                if ((strcmp(t->target.u.user.name,
 401                                            XT_STANDARD_TARGET) == 0) &&
 402                                    t->verdict < -NF_MAX_VERDICT - 1) {
 403                                        duprintf("mark_source_chains: bad "
 404                                                "negative verdict (%i)\n",
 405                                                                t->verdict);
 406                                        return 0;
 407                                }
 408
 409                                /* Return: backtrack through the last
 410                                 * big jump.
 411                                 */
 412                                do {
 413                                        e->comefrom ^= (1<<NF_ARP_NUMHOOKS);
 414                                        oldpos = pos;
 415                                        pos = e->counters.pcnt;
 416                                        e->counters.pcnt = 0;
 417
 418                                        /* We're at the start. */
 419                                        if (pos == oldpos)
 420                                                goto next;
 421
 422                                        e = (struct arpt_entry *)
 423                                                (entry0 + pos);
 424                                } while (oldpos == pos + e->next_offset);
 425
 426                                /* Move along one */
 427                                size = e->next_offset;
 428                                e = (struct arpt_entry *)
 429                                        (entry0 + pos + size);
 430                                e->counters.pcnt = pos;
 431                                pos += size;
 432                        } else {
 433                                int newpos = t->verdict;
 434
 435                                if (strcmp(t->target.u.user.name,
 436                                           XT_STANDARD_TARGET) == 0 &&
 437                                    newpos >= 0) {
 438                                        if (newpos > newinfo->size -
 439                                                sizeof(struct arpt_entry)) {
 440                                                duprintf("mark_source_chains: "
 441                                                        "bad verdict (%i)\n",
 442                                                                newpos);
 443                                                return 0;
 444                                        }
 445
 446                                        /* This a jump; chase it. */
 447                                        duprintf("Jump rule %u -> %u\n",
 448                                                 pos, newpos);
 449                                } else {
 450                                        /* ... this is a fallthru */
 451                                        newpos = pos + e->next_offset;
 452                                }
 453                                e = (struct arpt_entry *)
 454                                        (entry0 + newpos);
 455                                e->counters.pcnt = pos;
 456                                pos = newpos;
 457                        }
 458                }
 459                next:
 460                duprintf("Finished chain %u\n", hook);
 461        }
 462        return 1;
 463}
 464
 465static inline int check_entry(const struct arpt_entry *e, const char *name)
 466{
 467        const struct xt_entry_target *t;
 468
 469        if (!arp_checkentry(&e->arp)) {
 470                duprintf("arp_tables: arp check failed %p %s.\n", e, name);
 471                return -EINVAL;
 472        }
 473
 474        if (e->target_offset + sizeof(struct xt_entry_target) > e->next_offset)
 475                return -EINVAL;
 476
 477        t = arpt_get_target_c(e);
 478        if (e->target_offset + t->u.target_size > e->next_offset)
 479                return -EINVAL;
 480
 481        return 0;
 482}
 483
 484static inline int check_target(struct arpt_entry *e, const char *name)
 485{
 486        struct xt_entry_target *t = arpt_get_target(e);
 487        int ret;
 488        struct xt_tgchk_param par = {
 489                .table     = name,
 490                .entryinfo = e,
 491                .target    = t->u.kernel.target,
 492                .targinfo  = t->data,
 493                .hook_mask = e->comefrom,
 494                .family    = NFPROTO_ARP,
 495        };
 496
 497        ret = xt_check_target(&par, t->u.target_size - sizeof(*t), 0, false);
 498        if (ret < 0) {
 499                duprintf("arp_tables: check failed for `%s'.\n",
 500                         t->u.kernel.target->name);
 501                return ret;
 502        }
 503        return 0;
 504}
 505
 506static inline int
 507find_check_entry(struct arpt_entry *e, const char *name, unsigned int size)
 508{
 509        struct xt_entry_target *t;
 510        struct xt_target *target;
 511        int ret;
 512
 513        ret = check_entry(e, name);
 514        if (ret)
 515                return ret;
 516
 517        t = arpt_get_target(e);
 518        target = xt_request_find_target(NFPROTO_ARP, t->u.user.name,
 519                                        t->u.user.revision);
 520        if (IS_ERR(target)) {
 521                duprintf("find_check_entry: `%s' not found\n", t->u.user.name);
 522                ret = PTR_ERR(target);
 523                goto out;
 524        }
 525        t->u.kernel.target = target;
 526
 527        ret = check_target(e, name);
 528        if (ret)
 529                goto err;
 530        return 0;
 531err:
 532        module_put(t->u.kernel.target->me);
 533out:
 534        return ret;
 535}
 536
 537static bool check_underflow(const struct arpt_entry *e)
 538{
 539        const struct xt_entry_target *t;
 540        unsigned int verdict;
 541
 542        if (!unconditional(&e->arp))
 543                return false;
 544        t = arpt_get_target_c(e);
 545        if (strcmp(t->u.user.name, XT_STANDARD_TARGET) != 0)
 546                return false;
 547        verdict = ((struct xt_standard_target *)t)->verdict;
 548        verdict = -verdict - 1;
 549        return verdict == NF_DROP || verdict == NF_ACCEPT;
 550}
 551
 552static inline int check_entry_size_and_hooks(struct arpt_entry *e,
 553                                             struct xt_table_info *newinfo,
 554                                             const unsigned char *base,
 555                                             const unsigned char *limit,
 556                                             const unsigned int *hook_entries,
 557                                             const unsigned int *underflows,
 558                                             unsigned int valid_hooks)
 559{
 560        unsigned int h;
 561
 562        if ((unsigned long)e % __alignof__(struct arpt_entry) != 0 ||
 563            (unsigned char *)e + sizeof(struct arpt_entry) >= limit) {
 564                duprintf("Bad offset %p\n", e);
 565                return -EINVAL;
 566        }
 567
 568        if (e->next_offset
 569            < sizeof(struct arpt_entry) + sizeof(struct xt_entry_target)) {
 570                duprintf("checking: element %p size %u\n",
 571                         e, e->next_offset);
 572                return -EINVAL;
 573        }
 574
 575        /* Check hooks & underflows */
 576        for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
 577                if (!(valid_hooks & (1 << h)))
 578                        continue;
 579                if ((unsigned char *)e - base == hook_entries[h])
 580                        newinfo->hook_entry[h] = hook_entries[h];
 581                if ((unsigned char *)e - base == underflows[h]) {
 582                        if (!check_underflow(e)) {
 583                                pr_err("Underflows must be unconditional and "
 584                                       "use the STANDARD target with "
 585                                       "ACCEPT/DROP\n");
 586                                return -EINVAL;
 587                        }
 588                        newinfo->underflow[h] = underflows[h];
 589                }
 590        }
 591
 592        /* Clear counters and comefrom */
 593        e->counters = ((struct xt_counters) { 0, 0 });
 594        e->comefrom = 0;
 595        return 0;
 596}
 597
 598static inline void cleanup_entry(struct arpt_entry *e)
 599{
 600        struct xt_tgdtor_param par;
 601        struct xt_entry_target *t;
 602
 603        t = arpt_get_target(e);
 604        par.target   = t->u.kernel.target;
 605        par.targinfo = t->data;
 606        par.family   = NFPROTO_ARP;
 607        if (par.target->destroy != NULL)
 608                par.target->destroy(&par);
 609        module_put(par.target->me);
 610}
 611
 612/* Checks and translates the user-supplied table segment (held in
 613 * newinfo).
 614 */
 615static int translate_table(struct xt_table_info *newinfo, void *entry0,
 616                           const struct arpt_replace *repl)
 617{
 618        struct arpt_entry *iter;
 619        unsigned int i;
 620        int ret = 0;
 621
 622        newinfo->size = repl->size;
 623        newinfo->number = repl->num_entries;
 624
 625        /* Init all hooks to impossible value. */
 626        for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
 627                newinfo->hook_entry[i] = 0xFFFFFFFF;
 628                newinfo->underflow[i] = 0xFFFFFFFF;
 629        }
 630
 631        duprintf("translate_table: size %u\n", newinfo->size);
 632        i = 0;
 633
 634        /* Walk through entries, checking offsets. */
 635        xt_entry_foreach(iter, entry0, newinfo->size) {
 636                ret = check_entry_size_and_hooks(iter, newinfo, entry0,
 637                                                 entry0 + repl->size,
 638                                                 repl->hook_entry,
 639                                                 repl->underflow,
 640                                                 repl->valid_hooks);
 641                if (ret != 0)
 642                        break;
 643                ++i;
 644                if (strcmp(arpt_get_target(iter)->u.user.name,
 645                    XT_ERROR_TARGET) == 0)
 646                        ++newinfo->stacksize;
 647        }
 648        duprintf("translate_table: ARPT_ENTRY_ITERATE gives %d\n", ret);
 649        if (ret != 0)
 650                return ret;
 651
 652        if (i != repl->num_entries) {
 653                duprintf("translate_table: %u not %u entries\n",
 654                         i, repl->num_entries);
 655                return -EINVAL;
 656        }
 657
 658        /* Check hooks all assigned */
 659        for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
 660                /* Only hooks which are valid */
 661                if (!(repl->valid_hooks & (1 << i)))
 662                        continue;
 663                if (newinfo->hook_entry[i] == 0xFFFFFFFF) {
 664                        duprintf("Invalid hook entry %u %u\n",
 665                                 i, repl->hook_entry[i]);
 666                        return -EINVAL;
 667                }
 668                if (newinfo->underflow[i] == 0xFFFFFFFF) {
 669                        duprintf("Invalid underflow %u %u\n",
 670                                 i, repl->underflow[i]);
 671                        return -EINVAL;
 672                }
 673        }
 674
 675        if (!mark_source_chains(newinfo, repl->valid_hooks, entry0)) {
 676                duprintf("Looping hook\n");
 677                return -ELOOP;
 678        }
 679
 680        /* Finally, each sanity check must pass */
 681        i = 0;
 682        xt_entry_foreach(iter, entry0, newinfo->size) {
 683                ret = find_check_entry(iter, repl->name, repl->size);
 684                if (ret != 0)
 685                        break;
 686                ++i;
 687        }
 688
 689        if (ret != 0) {
 690                xt_entry_foreach(iter, entry0, newinfo->size) {
 691                        if (i-- == 0)
 692                                break;
 693                        cleanup_entry(iter);
 694                }
 695                return ret;
 696        }
 697
 698        /* And one copy for every other CPU */
 699        for_each_possible_cpu(i) {
 700                if (newinfo->entries[i] && newinfo->entries[i] != entry0)
 701                        memcpy(newinfo->entries[i], entry0, newinfo->size);
 702        }
 703
 704        return ret;
 705}
 706
 707static void get_counters(const struct xt_table_info *t,
 708                         struct xt_counters counters[])
 709{
 710        struct arpt_entry *iter;
 711        unsigned int cpu;
 712        unsigned int i;
 713
 714        for_each_possible_cpu(cpu) {
 715                seqlock_t *lock = &per_cpu(xt_info_locks, cpu).lock;
 716
 717                i = 0;
 718                xt_entry_foreach(iter, t->entries[cpu], t->size) {
 719                        u64 bcnt, pcnt;
 720                        unsigned int start;
 721
 722                        do {
 723                                start = read_seqbegin(lock);
 724                                bcnt = iter->counters.bcnt;
 725                                pcnt = iter->counters.pcnt;
 726                        } while (read_seqretry(lock, start));
 727
 728                        ADD_COUNTER(counters[i], bcnt, pcnt);
 729                        ++i;
 730                }
 731        }
 732}
 733
 734static struct xt_counters *alloc_counters(const struct xt_table *table)
 735{
 736        unsigned int countersize;
 737        struct xt_counters *counters;
 738        const struct xt_table_info *private = table->private;
 739
 740        /* We need atomic snapshot of counters: rest doesn't change
 741         * (other than comefrom, which userspace doesn't care
 742         * about).
 743         */
 744        countersize = sizeof(struct xt_counters) * private->number;
 745        counters = vzalloc(countersize);
 746
 747        if (counters == NULL)
 748                return ERR_PTR(-ENOMEM);
 749
 750        get_counters(private, counters);
 751
 752        return counters;
 753}
 754
 755static int copy_entries_to_user(unsigned int total_size,
 756                                const struct xt_table *table,
 757                                void __user *userptr)
 758{
 759        unsigned int off, num;
 760        const struct arpt_entry *e;
 761        struct xt_counters *counters;
 762        struct xt_table_info *private = table->private;
 763        int ret = 0;
 764        void *loc_cpu_entry;
 765
 766        counters = alloc_counters(table);
 767        if (IS_ERR(counters))
 768                return PTR_ERR(counters);
 769
 770        loc_cpu_entry = private->entries[raw_smp_processor_id()];
 771        /* ... then copy entire thing ... */
 772        if (copy_to_user(userptr, loc_cpu_entry, total_size) != 0) {
 773                ret = -EFAULT;
 774                goto free_counters;
 775        }
 776
 777        /* FIXME: use iterator macros --RR */
 778        /* ... then go back and fix counters and names */
 779        for (off = 0, num = 0; off < total_size; off += e->next_offset, num++){
 780                const struct xt_entry_target *t;
 781
 782                e = (struct arpt_entry *)(loc_cpu_entry + off);
 783                if (copy_to_user(userptr + off
 784                                 + offsetof(struct arpt_entry, counters),
 785                                 &counters[num],
 786                                 sizeof(counters[num])) != 0) {
 787                        ret = -EFAULT;
 788                        goto free_counters;
 789                }
 790
 791                t = arpt_get_target_c(e);
 792                if (copy_to_user(userptr + off + e->target_offset
 793                                 + offsetof(struct xt_entry_target,
 794                                            u.user.name),
 795                                 t->u.kernel.target->name,
 796                                 strlen(t->u.kernel.target->name)+1) != 0) {
 797                        ret = -EFAULT;
 798                        goto free_counters;
 799                }
 800        }
 801
 802 free_counters:
 803        vfree(counters);
 804        return ret;
 805}
 806
 807#ifdef CONFIG_COMPAT
 808static void compat_standard_from_user(void *dst, const void *src)
 809{
 810        int v = *(compat_int_t *)src;
 811
 812        if (v > 0)
 813                v += xt_compat_calc_jump(NFPROTO_ARP, v);
 814        memcpy(dst, &v, sizeof(v));
 815}
 816
 817static int compat_standard_to_user(void __user *dst, const void *src)
 818{
 819        compat_int_t cv = *(int *)src;
 820
 821        if (cv > 0)
 822                cv -= xt_compat_calc_jump(NFPROTO_ARP, cv);
 823        return copy_to_user(dst, &cv, sizeof(cv)) ? -EFAULT : 0;
 824}
 825
 826static int compat_calc_entry(const struct arpt_entry *e,
 827                             const struct xt_table_info *info,
 828                             const void *base, struct xt_table_info *newinfo)
 829{
 830        const struct xt_entry_target *t;
 831        unsigned int entry_offset;
 832        int off, i, ret;
 833
 834        off = sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
 835        entry_offset = (void *)e - base;
 836
 837        t = arpt_get_target_c(e);
 838        off += xt_compat_target_offset(t->u.kernel.target);
 839        newinfo->size -= off;
 840        ret = xt_compat_add_offset(NFPROTO_ARP, entry_offset, off);
 841        if (ret)
 842                return ret;
 843
 844        for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
 845                if (info->hook_entry[i] &&
 846                    (e < (struct arpt_entry *)(base + info->hook_entry[i])))
 847                        newinfo->hook_entry[i] -= off;
 848                if (info->underflow[i] &&
 849                    (e < (struct arpt_entry *)(base + info->underflow[i])))
 850                        newinfo->underflow[i] -= off;
 851        }
 852        return 0;
 853}
 854
 855static int compat_table_info(const struct xt_table_info *info,
 856                             struct xt_table_info *newinfo)
 857{
 858        struct arpt_entry *iter;
 859        void *loc_cpu_entry;
 860        int ret;
 861
 862        if (!newinfo || !info)
 863                return -EINVAL;
 864
 865        /* we dont care about newinfo->entries[] */
 866        memcpy(newinfo, info, offsetof(struct xt_table_info, entries));
 867        newinfo->initial_entries = 0;
 868        loc_cpu_entry = info->entries[raw_smp_processor_id()];
 869        xt_entry_foreach(iter, loc_cpu_entry, info->size) {
 870                ret = compat_calc_entry(iter, info, loc_cpu_entry, newinfo);
 871                if (ret != 0)
 872                        return ret;
 873        }
 874        return 0;
 875}
 876#endif
 877
 878static int get_info(struct net *net, void __user *user,
 879                    const int *len, int compat)
 880{
 881        char name[XT_TABLE_MAXNAMELEN];
 882        struct xt_table *t;
 883        int ret;
 884
 885        if (*len != sizeof(struct arpt_getinfo)) {
 886                duprintf("length %u != %Zu\n", *len,
 887                         sizeof(struct arpt_getinfo));
 888                return -EINVAL;
 889        }
 890
 891        if (copy_from_user(name, user, sizeof(name)) != 0)
 892                return -EFAULT;
 893
 894        name[XT_TABLE_MAXNAMELEN-1] = '\0';
 895#ifdef CONFIG_COMPAT
 896        if (compat)
 897                xt_compat_lock(NFPROTO_ARP);
 898#endif
 899        t = try_then_request_module(xt_find_table_lock(net, NFPROTO_ARP, name),
 900                                    "arptable_%s", name);
 901        if (t && !IS_ERR(t)) {
 902                struct arpt_getinfo info;
 903                const struct xt_table_info *private = t->private;
 904#ifdef CONFIG_COMPAT
 905                struct xt_table_info tmp;
 906
 907                if (compat) {
 908                        ret = compat_table_info(private, &tmp);
 909                        xt_compat_flush_offsets(NFPROTO_ARP);
 910                        private = &tmp;
 911                }
 912#endif
 913                memset(&info, 0, sizeof(info));
 914                info.valid_hooks = t->valid_hooks;
 915                memcpy(info.hook_entry, private->hook_entry,
 916                       sizeof(info.hook_entry));
 917                memcpy(info.underflow, private->underflow,
 918                       sizeof(info.underflow));
 919                info.num_entries = private->number;
 920                info.size = private->size;
 921                strcpy(info.name, name);
 922
 923                if (copy_to_user(user, &info, *len) != 0)
 924                        ret = -EFAULT;
 925                else
 926                        ret = 0;
 927                xt_table_unlock(t);
 928                module_put(t->me);
 929        } else
 930                ret = t ? PTR_ERR(t) : -ENOENT;
 931#ifdef CONFIG_COMPAT
 932        if (compat)
 933                xt_compat_unlock(NFPROTO_ARP);
 934#endif
 935        return ret;
 936}
 937
 938static int get_entries(struct net *net, struct arpt_get_entries __user *uptr,
 939                       const int *len)
 940{
 941        int ret;
 942        struct arpt_get_entries get;
 943        struct xt_table *t;
 944
 945        if (*len < sizeof(get)) {
 946                duprintf("get_entries: %u < %Zu\n", *len, sizeof(get));
 947                return -EINVAL;
 948        }
 949        if (copy_from_user(&get, uptr, sizeof(get)) != 0)
 950                return -EFAULT;
 951        if (*len != sizeof(struct arpt_get_entries) + get.size) {
 952                duprintf("get_entries: %u != %Zu\n", *len,
 953                         sizeof(struct arpt_get_entries) + get.size);
 954                return -EINVAL;
 955        }
 956
 957        t = xt_find_table_lock(net, NFPROTO_ARP, get.name);
 958        if (t && !IS_ERR(t)) {
 959                const struct xt_table_info *private = t->private;
 960
 961                duprintf("t->private->number = %u\n",
 962                         private->number);
 963                if (get.size == private->size)
 964                        ret = copy_entries_to_user(private->size,
 965                                                   t, uptr->entrytable);
 966                else {
 967                        duprintf("get_entries: I've got %u not %u!\n",
 968                                 private->size, get.size);
 969                        ret = -EAGAIN;
 970                }
 971                module_put(t->me);
 972                xt_table_unlock(t);
 973        } else
 974                ret = t ? PTR_ERR(t) : -ENOENT;
 975
 976        return ret;
 977}
 978
 979static int __do_replace(struct net *net, const char *name,
 980                        unsigned int valid_hooks,
 981                        struct xt_table_info *newinfo,
 982                        unsigned int num_counters,
 983                        void __user *counters_ptr)
 984{
 985        int ret;
 986        struct xt_table *t;
 987        struct xt_table_info *oldinfo;
 988        struct xt_counters *counters;
 989        void *loc_cpu_old_entry;
 990        struct arpt_entry *iter;
 991
 992        ret = 0;
 993        counters = vzalloc(num_counters * sizeof(struct xt_counters));
 994        if (!counters) {
 995                ret = -ENOMEM;
 996                goto out;
 997        }
 998
 999        t = try_then_request_module(xt_find_table_lock(net, NFPROTO_ARP, name),
1000                                    "arptable_%s", name);
1001        if (!t || IS_ERR(t)) {
1002                ret = t ? PTR_ERR(t) : -ENOENT;
1003                goto free_newinfo_counters_untrans;
1004        }
1005
1006        /* You lied! */
1007        if (valid_hooks != t->valid_hooks) {
1008                duprintf("Valid hook crap: %08X vs %08X\n",
1009                         valid_hooks, t->valid_hooks);
1010                ret = -EINVAL;
1011                goto put_module;
1012        }
1013
1014        oldinfo = xt_replace_table(t, num_counters, newinfo, &ret);
1015        if (!oldinfo)
1016                goto put_module;
1017
1018        /* Update module usage count based on number of rules */
1019        duprintf("do_replace: oldnum=%u, initnum=%u, newnum=%u\n",
1020                oldinfo->number, oldinfo->initial_entries, newinfo->number);
1021        if ((oldinfo->number > oldinfo->initial_entries) ||
1022            (newinfo->number <= oldinfo->initial_entries))
1023                module_put(t->me);
1024        if ((oldinfo->number > oldinfo->initial_entries) &&
1025            (newinfo->number <= oldinfo->initial_entries))
1026                module_put(t->me);
1027
1028        /* Get the old counters, and synchronize with replace */
1029        get_counters(oldinfo, counters);
1030
1031        /* Decrease module usage counts and free resource */
1032        loc_cpu_old_entry = oldinfo->entries[raw_smp_processor_id()];
1033        xt_entry_foreach(iter, loc_cpu_old_entry, oldinfo->size)
1034                cleanup_entry(iter);
1035
1036        xt_free_table_info(oldinfo);
1037        if (copy_to_user(counters_ptr, counters,
1038                         sizeof(struct xt_counters) * num_counters) != 0)
1039                ret = -EFAULT;
1040        vfree(counters);
1041        xt_table_unlock(t);
1042        return ret;
1043
1044 put_module:
1045        module_put(t->me);
1046        xt_table_unlock(t);
1047 free_newinfo_counters_untrans:
1048        vfree(counters);
1049 out:
1050        return ret;
1051}
1052
1053static int do_replace(struct net *net, const void __user *user,
1054                      unsigned int len)
1055{
1056        int ret;
1057        struct arpt_replace tmp;
1058        struct xt_table_info *newinfo;
1059        void *loc_cpu_entry;
1060        struct arpt_entry *iter;
1061
1062        if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
1063                return -EFAULT;
1064
1065        /* overflow check */
1066        if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
1067                return -ENOMEM;
1068
1069        newinfo = xt_alloc_table_info(tmp.size);
1070        if (!newinfo)
1071                return -ENOMEM;
1072
1073        /* choose the copy that is on our node/cpu */
1074        loc_cpu_entry = newinfo->entries[raw_smp_processor_id()];
1075        if (copy_from_user(loc_cpu_entry, user + sizeof(tmp),
1076                           tmp.size) != 0) {
1077                ret = -EFAULT;
1078                goto free_newinfo;
1079        }
1080
1081        ret = translate_table(newinfo, loc_cpu_entry, &tmp);
1082        if (ret != 0)
1083                goto free_newinfo;
1084
1085        duprintf("arp_tables: Translated table\n");
1086
1087        ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo,
1088                           tmp.num_counters, tmp.counters);
1089        if (ret)
1090                goto free_newinfo_untrans;
1091        return 0;
1092
1093 free_newinfo_untrans:
1094        xt_entry_foreach(iter, loc_cpu_entry, newinfo->size)
1095                cleanup_entry(iter);
1096 free_newinfo:
1097        xt_free_table_info(newinfo);
1098        return ret;
1099}
1100
1101static int do_add_counters(struct net *net, const void __user *user,
1102                           unsigned int len, int compat)
1103{
1104        unsigned int i, curcpu;
1105        struct xt_counters_info tmp;
1106        struct xt_counters *paddc;
1107        unsigned int num_counters;
1108        const char *name;
1109        int size;
1110        void *ptmp;
1111        struct xt_table *t;
1112        const struct xt_table_info *private;
1113        int ret = 0;
1114        void *loc_cpu_entry;
1115        struct arpt_entry *iter;
1116#ifdef CONFIG_COMPAT
1117        struct compat_xt_counters_info compat_tmp;
1118
1119        if (compat) {
1120                ptmp = &compat_tmp;
1121                size = sizeof(struct compat_xt_counters_info);
1122        } else
1123#endif
1124        {
1125                ptmp = &tmp;
1126                size = sizeof(struct xt_counters_info);
1127        }
1128
1129        if (copy_from_user(ptmp, user, size) != 0)
1130                return -EFAULT;
1131
1132#ifdef CONFIG_COMPAT
1133        if (compat) {
1134                num_counters = compat_tmp.num_counters;
1135                name = compat_tmp.name;
1136        } else
1137#endif
1138        {
1139                num_counters = tmp.num_counters;
1140                name = tmp.name;
1141        }
1142
1143        if (len != size + num_counters * sizeof(struct xt_counters))
1144                return -EINVAL;
1145
1146        paddc = vmalloc(len - size);
1147        if (!paddc)
1148                return -ENOMEM;
1149
1150        if (copy_from_user(paddc, user + size, len - size) != 0) {
1151                ret = -EFAULT;
1152                goto free;
1153        }
1154
1155        t = xt_find_table_lock(net, NFPROTO_ARP, name);
1156        if (!t || IS_ERR(t)) {
1157                ret = t ? PTR_ERR(t) : -ENOENT;
1158                goto free;
1159        }
1160
1161        local_bh_disable();
1162        private = t->private;
1163        if (private->number != num_counters) {
1164                ret = -EINVAL;
1165                goto unlock_up_free;
1166        }
1167
1168        i = 0;
1169        /* Choose the copy that is on our node */
1170        curcpu = smp_processor_id();
1171        loc_cpu_entry = private->entries[curcpu];
1172        xt_info_wrlock(curcpu);
1173        xt_entry_foreach(iter, loc_cpu_entry, private->size) {
1174                ADD_COUNTER(iter->counters, paddc[i].bcnt, paddc[i].pcnt);
1175                ++i;
1176        }
1177        xt_info_wrunlock(curcpu);
1178 unlock_up_free:
1179        local_bh_enable();
1180        xt_table_unlock(t);
1181        module_put(t->me);
1182 free:
1183        vfree(paddc);
1184
1185        return ret;
1186}
1187
1188#ifdef CONFIG_COMPAT
1189static inline void compat_release_entry(struct compat_arpt_entry *e)
1190{
1191        struct xt_entry_target *t;
1192
1193        t = compat_arpt_get_target(e);
1194        module_put(t->u.kernel.target->me);
1195}
1196
1197static inline int
1198check_compat_entry_size_and_hooks(struct compat_arpt_entry *e,
1199                                  struct xt_table_info *newinfo,
1200                                  unsigned int *size,
1201                                  const unsigned char *base,
1202                                  const unsigned char *limit,
1203                                  const unsigned int *hook_entries,
1204                                  const unsigned int *underflows,
1205                                  const char *name)
1206{
1207        struct xt_entry_target *t;
1208        struct xt_target *target;
1209        unsigned int entry_offset;
1210        int ret, off, h;
1211
1212        duprintf("check_compat_entry_size_and_hooks %p\n", e);
1213        if ((unsigned long)e % __alignof__(struct compat_arpt_entry) != 0 ||
1214            (unsigned char *)e + sizeof(struct compat_arpt_entry) >= limit) {
1215                duprintf("Bad offset %p, limit = %p\n", e, limit);
1216                return -EINVAL;
1217        }
1218
1219        if (e->next_offset < sizeof(struct compat_arpt_entry) +
1220                             sizeof(struct compat_xt_entry_target)) {
1221                duprintf("checking: element %p size %u\n",
1222                         e, e->next_offset);
1223                return -EINVAL;
1224        }
1225
1226        /* For purposes of check_entry casting the compat entry is fine */
1227        ret = check_entry((struct arpt_entry *)e, name);
1228        if (ret)
1229                return ret;
1230
1231        off = sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1232        entry_offset = (void *)e - (void *)base;
1233
1234        t = compat_arpt_get_target(e);
1235        target = xt_request_find_target(NFPROTO_ARP, t->u.user.name,
1236                                        t->u.user.revision);
1237        if (IS_ERR(target)) {
1238                duprintf("check_compat_entry_size_and_hooks: `%s' not found\n",
1239                         t->u.user.name);
1240                ret = PTR_ERR(target);
1241                goto out;
1242        }
1243        t->u.kernel.target = target;
1244
1245        off += xt_compat_target_offset(target);
1246        *size += off;
1247        ret = xt_compat_add_offset(NFPROTO_ARP, entry_offset, off);
1248        if (ret)
1249                goto release_target;
1250
1251        /* Check hooks & underflows */
1252        for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
1253                if ((unsigned char *)e - base == hook_entries[h])
1254                        newinfo->hook_entry[h] = hook_entries[h];
1255                if ((unsigned char *)e - base == underflows[h])
1256                        newinfo->underflow[h] = underflows[h];
1257        }
1258
1259        /* Clear counters and comefrom */
1260        memset(&e->counters, 0, sizeof(e->counters));
1261        e->comefrom = 0;
1262        return 0;
1263
1264release_target:
1265        module_put(t->u.kernel.target->me);
1266out:
1267        return ret;
1268}
1269
1270static int
1271compat_copy_entry_from_user(struct compat_arpt_entry *e, void **dstptr,
1272                            unsigned int *size, const char *name,
1273                            struct xt_table_info *newinfo, unsigned char *base)
1274{
1275        struct xt_entry_target *t;
1276        struct xt_target *target;
1277        struct arpt_entry *de;
1278        unsigned int origsize;
1279        int ret, h;
1280
1281        ret = 0;
1282        origsize = *size;
1283        de = (struct arpt_entry *)*dstptr;
1284        memcpy(de, e, sizeof(struct arpt_entry));
1285        memcpy(&de->counters, &e->counters, sizeof(e->counters));
1286
1287        *dstptr += sizeof(struct arpt_entry);
1288        *size += sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1289
1290        de->target_offset = e->target_offset - (origsize - *size);
1291        t = compat_arpt_get_target(e);
1292        target = t->u.kernel.target;
1293        xt_compat_target_from_user(t, dstptr, size);
1294
1295        de->next_offset = e->next_offset - (origsize - *size);
1296        for (h = 0; h < NF_ARP_NUMHOOKS; h++) {
1297                if ((unsigned char *)de - base < newinfo->hook_entry[h])
1298                        newinfo->hook_entry[h] -= origsize - *size;
1299                if ((unsigned char *)de - base < newinfo->underflow[h])
1300                        newinfo->underflow[h] -= origsize - *size;
1301        }
1302        return ret;
1303}
1304
1305static int translate_compat_table(const char *name,
1306                                  unsigned int valid_hooks,
1307                                  struct xt_table_info **pinfo,
1308                                  void **pentry0,
1309                                  unsigned int total_size,
1310                                  unsigned int number,
1311                                  unsigned int *hook_entries,
1312                                  unsigned int *underflows)
1313{
1314        unsigned int i, j;
1315        struct xt_table_info *newinfo, *info;
1316        void *pos, *entry0, *entry1;
1317        struct compat_arpt_entry *iter0;
1318        struct arpt_entry *iter1;
1319        unsigned int size;
1320        int ret = 0;
1321
1322        info = *pinfo;
1323        entry0 = *pentry0;
1324        size = total_size;
1325        info->number = number;
1326
1327        /* Init all hooks to impossible value. */
1328        for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
1329                info->hook_entry[i] = 0xFFFFFFFF;
1330                info->underflow[i] = 0xFFFFFFFF;
1331        }
1332
1333        duprintf("translate_compat_table: size %u\n", info->size);
1334        j = 0;
1335        xt_compat_lock(NFPROTO_ARP);
1336        /* Walk through entries, checking offsets. */
1337        xt_entry_foreach(iter0, entry0, total_size) {
1338                ret = check_compat_entry_size_and_hooks(iter0, info, &size,
1339                                                        entry0,
1340                                                        entry0 + total_size,
1341                                                        hook_entries,
1342                                                        underflows,
1343                                                        name);
1344                if (ret != 0)
1345                        goto out_unlock;
1346                ++j;
1347        }
1348
1349        ret = -EINVAL;
1350        if (j != number) {
1351                duprintf("translate_compat_table: %u not %u entries\n",
1352                         j, number);
1353                goto out_unlock;
1354        }
1355
1356        /* Check hooks all assigned */
1357        for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
1358                /* Only hooks which are valid */
1359                if (!(valid_hooks & (1 << i)))
1360                        continue;
1361                if (info->hook_entry[i] == 0xFFFFFFFF) {
1362                        duprintf("Invalid hook entry %u %u\n",
1363                                 i, hook_entries[i]);
1364                        goto out_unlock;
1365                }
1366                if (info->underflow[i] == 0xFFFFFFFF) {
1367                        duprintf("Invalid underflow %u %u\n",
1368                                 i, underflows[i]);
1369                        goto out_unlock;
1370                }
1371        }
1372
1373        ret = -ENOMEM;
1374        newinfo = xt_alloc_table_info(size);
1375        if (!newinfo)
1376                goto out_unlock;
1377
1378        newinfo->number = number;
1379        for (i = 0; i < NF_ARP_NUMHOOKS; i++) {
1380                newinfo->hook_entry[i] = info->hook_entry[i];
1381                newinfo->underflow[i] = info->underflow[i];
1382        }
1383        entry1 = newinfo->entries[raw_smp_processor_id()];
1384        pos = entry1;
1385        size = total_size;
1386        xt_entry_foreach(iter0, entry0, total_size) {
1387                ret = compat_copy_entry_from_user(iter0, &pos, &size,
1388                                                  name, newinfo, entry1);
1389                if (ret != 0)
1390                        break;
1391        }
1392        xt_compat_flush_offsets(NFPROTO_ARP);
1393        xt_compat_unlock(NFPROTO_ARP);
1394        if (ret)
1395                goto free_newinfo;
1396
1397        ret = -ELOOP;
1398        if (!mark_source_chains(newinfo, valid_hooks, entry1))
1399                goto free_newinfo;
1400
1401        i = 0;
1402        xt_entry_foreach(iter1, entry1, newinfo->size) {
1403                ret = check_target(iter1, name);
1404                if (ret != 0)
1405                        break;
1406                ++i;
1407                if (strcmp(arpt_get_target(iter1)->u.user.name,
1408                    XT_ERROR_TARGET) == 0)
1409                        ++newinfo->stacksize;
1410        }
1411        if (ret) {
1412                /*
1413                 * The first i matches need cleanup_entry (calls ->destroy)
1414                 * because they had called ->check already. The other j-i
1415                 * entries need only release.
1416                 */
1417                int skip = i;
1418                j -= i;
1419                xt_entry_foreach(iter0, entry0, newinfo->size) {
1420                        if (skip-- > 0)
1421                                continue;
1422                        if (j-- == 0)
1423                                break;
1424                        compat_release_entry(iter0);
1425                }
1426                xt_entry_foreach(iter1, entry1, newinfo->size) {
1427                        if (i-- == 0)
1428                                break;
1429                        cleanup_entry(iter1);
1430                }
1431                xt_free_table_info(newinfo);
1432                return ret;
1433        }
1434
1435        /* And one copy for every other CPU */
1436        for_each_possible_cpu(i)
1437                if (newinfo->entries[i] && newinfo->entries[i] != entry1)
1438                        memcpy(newinfo->entries[i], entry1, newinfo->size);
1439
1440        *pinfo = newinfo;
1441        *pentry0 = entry1;
1442        xt_free_table_info(info);
1443        return 0;
1444
1445free_newinfo:
1446        xt_free_table_info(newinfo);
1447out:
1448        xt_entry_foreach(iter0, entry0, total_size) {
1449                if (j-- == 0)
1450                        break;
1451                compat_release_entry(iter0);
1452        }
1453        return ret;
1454out_unlock:
1455        xt_compat_flush_offsets(NFPROTO_ARP);
1456        xt_compat_unlock(NFPROTO_ARP);
1457        goto out;
1458}
1459
1460struct compat_arpt_replace {
1461        char                            name[XT_TABLE_MAXNAMELEN];
1462        u32                             valid_hooks;
1463        u32                             num_entries;
1464        u32                             size;
1465        u32                             hook_entry[NF_ARP_NUMHOOKS];
1466        u32                             underflow[NF_ARP_NUMHOOKS];
1467        u32                             num_counters;
1468        compat_uptr_t                   counters;
1469        struct compat_arpt_entry        entries[0];
1470};
1471
1472static int compat_do_replace(struct net *net, void __user *user,
1473                             unsigned int len)
1474{
1475        int ret;
1476        struct compat_arpt_replace tmp;
1477        struct xt_table_info *newinfo;
1478        void *loc_cpu_entry;
1479        struct arpt_entry *iter;
1480
1481        if (copy_from_user(&tmp, user, sizeof(tmp)) != 0)
1482                return -EFAULT;
1483
1484        /* overflow check */
1485        if (tmp.size >= INT_MAX / num_possible_cpus())
1486                return -ENOMEM;
1487        if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
1488                return -ENOMEM;
1489
1490        newinfo = xt_alloc_table_info(tmp.size);
1491        if (!newinfo)
1492                return -ENOMEM;
1493
1494        /* choose the copy that is on our node/cpu */
1495        loc_cpu_entry = newinfo->entries[raw_smp_processor_id()];
1496        if (copy_from_user(loc_cpu_entry, user + sizeof(tmp), tmp.size) != 0) {
1497                ret = -EFAULT;
1498                goto free_newinfo;
1499        }
1500
1501        ret = translate_compat_table(tmp.name, tmp.valid_hooks,
1502                                     &newinfo, &loc_cpu_entry, tmp.size,
1503                                     tmp.num_entries, tmp.hook_entry,
1504                                     tmp.underflow);
1505        if (ret != 0)
1506                goto free_newinfo;
1507
1508        duprintf("compat_do_replace: Translated table\n");
1509
1510        ret = __do_replace(net, tmp.name, tmp.valid_hooks, newinfo,
1511                           tmp.num_counters, compat_ptr(tmp.counters));
1512        if (ret)
1513                goto free_newinfo_untrans;
1514        return 0;
1515
1516 free_newinfo_untrans:
1517        xt_entry_foreach(iter, loc_cpu_entry, newinfo->size)
1518                cleanup_entry(iter);
1519 free_newinfo:
1520        xt_free_table_info(newinfo);
1521        return ret;
1522}
1523
1524static int compat_do_arpt_set_ctl(struct sock *sk, int cmd, void __user *user,
1525                                  unsigned int len)
1526{
1527        int ret;
1528
1529        if (!capable(CAP_NET_ADMIN))
1530                return -EPERM;
1531
1532        switch (cmd) {
1533        case ARPT_SO_SET_REPLACE:
1534                ret = compat_do_replace(sock_net(sk), user, len);
1535                break;
1536
1537        case ARPT_SO_SET_ADD_COUNTERS:
1538                ret = do_add_counters(sock_net(sk), user, len, 1);
1539                break;
1540
1541        default:
1542                duprintf("do_arpt_set_ctl:  unknown request %i\n", cmd);
1543                ret = -EINVAL;
1544        }
1545
1546        return ret;
1547}
1548
1549static int compat_copy_entry_to_user(struct arpt_entry *e, void __user **dstptr,
1550                                     compat_uint_t *size,
1551                                     struct xt_counters *counters,
1552                                     unsigned int i)
1553{
1554        struct xt_entry_target *t;
1555        struct compat_arpt_entry __user *ce;
1556        u_int16_t target_offset, next_offset;
1557        compat_uint_t origsize;
1558        int ret;
1559
1560        origsize = *size;
1561        ce = (struct compat_arpt_entry __user *)*dstptr;
1562        if (copy_to_user(ce, e, sizeof(struct arpt_entry)) != 0 ||
1563            copy_to_user(&ce->counters, &counters[i],
1564            sizeof(counters[i])) != 0)
1565                return -EFAULT;
1566
1567        *dstptr += sizeof(struct compat_arpt_entry);
1568        *size -= sizeof(struct arpt_entry) - sizeof(struct compat_arpt_entry);
1569
1570        target_offset = e->target_offset - (origsize - *size);
1571
1572        t = arpt_get_target(e);
1573        ret = xt_compat_target_to_user(t, dstptr, size);
1574        if (ret)
1575                return ret;
1576        next_offset = e->next_offset - (origsize - *size);
1577        if (put_user(target_offset, &ce->target_offset) != 0 ||
1578            put_user(next_offset, &ce->next_offset) != 0)
1579                return -EFAULT;
1580        return 0;
1581}
1582
1583static int compat_copy_entries_to_user(unsigned int total_size,
1584                                       struct xt_table *table,
1585                                       void __user *userptr)
1586{
1587        struct xt_counters *counters;
1588        const struct xt_table_info *private = table->private;
1589        void __user *pos;
1590        unsigned int size;
1591        int ret = 0;
1592        void *loc_cpu_entry;
1593        unsigned int i = 0;
1594        struct arpt_entry *iter;
1595
1596        counters = alloc_counters(table);
1597        if (IS_ERR(counters))
1598                return PTR_ERR(counters);
1599
1600        /* choose the copy on our node/cpu */
1601        loc_cpu_entry = private->entries[raw_smp_processor_id()];
1602        pos = userptr;
1603        size = total_size;
1604        xt_entry_foreach(iter, loc_cpu_entry, total_size) {
1605                ret = compat_copy_entry_to_user(iter, &pos,
1606                                                &size, counters, i++);
1607                if (ret != 0)
1608                        break;
1609        }
1610        vfree(counters);
1611        return ret;
1612}
1613
1614struct compat_arpt_get_entries {
1615        char name[XT_TABLE_MAXNAMELEN];
1616        compat_uint_t size;
1617        struct compat_arpt_entry entrytable[0];
1618};
1619
1620static int compat_get_entries(struct net *net,
1621                              struct compat_arpt_get_entries __user *uptr,
1622                              int *len)
1623{
1624        int ret;
1625        struct compat_arpt_get_entries get;
1626        struct xt_table *t;
1627
1628        if (*len < sizeof(get)) {
1629                duprintf("compat_get_entries: %u < %zu\n", *len, sizeof(get));
1630                return -EINVAL;
1631        }
1632        if (copy_from_user(&get, uptr, sizeof(get)) != 0)
1633                return -EFAULT;
1634        if (*len != sizeof(struct compat_arpt_get_entries) + get.size) {
1635                duprintf("compat_get_entries: %u != %zu\n",
1636                         *len, sizeof(get) + get.size);
1637                return -EINVAL;
1638        }
1639
1640        xt_compat_lock(NFPROTO_ARP);
1641        t = xt_find_table_lock(net, NFPROTO_ARP, get.name);
1642        if (t && !IS_ERR(t)) {
1643                const struct xt_table_info *private = t->private;
1644                struct xt_table_info info;
1645
1646                duprintf("t->private->number = %u\n", private->number);
1647                ret = compat_table_info(private, &info);
1648                if (!ret && get.size == info.size) {
1649                        ret = compat_copy_entries_to_user(private->size,
1650                                                          t, uptr->entrytable);
1651                } else if (!ret) {
1652                        duprintf("compat_get_entries: I've got %u not %u!\n",
1653                                 private->size, get.size);
1654                        ret = -EAGAIN;
1655                }
1656                xt_compat_flush_offsets(NFPROTO_ARP);
1657                module_put(t->me);
1658                xt_table_unlock(t);
1659        } else
1660                ret = t ? PTR_ERR(t) : -ENOENT;
1661
1662        xt_compat_unlock(NFPROTO_ARP);
1663        return ret;
1664}
1665
1666static int do_arpt_get_ctl(struct sock *, int, void __user *, int *);
1667
1668static int compat_do_arpt_get_ctl(struct sock *sk, int cmd, void __user *user,
1669                                  int *len)
1670{
1671        int ret;
1672
1673        if (!capable(CAP_NET_ADMIN))
1674                return -EPERM;
1675
1676        switch (cmd) {
1677        case ARPT_SO_GET_INFO:
1678                ret = get_info(sock_net(sk), user, len, 1);
1679                break;
1680        case ARPT_SO_GET_ENTRIES:
1681                ret = compat_get_entries(sock_net(sk), user, len);
1682                break;
1683        default:
1684                ret = do_arpt_get_ctl(sk, cmd, user, len);
1685        }
1686        return ret;
1687}
1688#endif
1689
1690static int do_arpt_set_ctl(struct sock *sk, int cmd, void __user *user, unsigned int len)
1691{
1692        int ret;
1693
1694        if (!capable(CAP_NET_ADMIN))
1695                return -EPERM;
1696
1697        switch (cmd) {
1698        case ARPT_SO_SET_REPLACE:
1699                ret = do_replace(sock_net(sk), user, len);
1700                break;
1701
1702        case ARPT_SO_SET_ADD_COUNTERS:
1703                ret = do_add_counters(sock_net(sk), user, len, 0);
1704                break;
1705
1706        default:
1707                duprintf("do_arpt_set_ctl:  unknown request %i\n", cmd);
1708                ret = -EINVAL;
1709        }
1710
1711        return ret;
1712}
1713
1714static int do_arpt_get_ctl(struct sock *sk, int cmd, void __user *user, int *len)
1715{
1716        int ret;
1717
1718        if (!capable(CAP_NET_ADMIN))
1719                return -EPERM;
1720
1721        switch (cmd) {
1722        case ARPT_SO_GET_INFO:
1723                ret = get_info(sock_net(sk), user, len, 0);
1724                break;
1725
1726        case ARPT_SO_GET_ENTRIES:
1727                ret = get_entries(sock_net(sk), user, len);
1728                break;
1729
1730        case ARPT_SO_GET_REVISION_TARGET: {
1731                struct xt_get_revision rev;
1732
1733                if (*len != sizeof(rev)) {
1734                        ret = -EINVAL;
1735                        break;
1736                }
1737                if (copy_from_user(&rev, user, sizeof(rev)) != 0) {
1738                        ret = -EFAULT;
1739                        break;
1740                }
1741
1742                try_then_request_module(xt_find_revision(NFPROTO_ARP, rev.name,
1743                                                         rev.revision, 1, &ret),
1744                                        "arpt_%s", rev.name);
1745                break;
1746        }
1747
1748        default:
1749                duprintf("do_arpt_get_ctl: unknown request %i\n", cmd);
1750                ret = -EINVAL;
1751        }
1752
1753        return ret;
1754}
1755
1756struct xt_table *arpt_register_table(struct net *net,
1757                                     const struct xt_table *table,
1758                                     const struct arpt_replace *repl)
1759{
1760        int ret;
1761        struct xt_table_info *newinfo;
1762        struct xt_table_info bootstrap = {0};
1763        void *loc_cpu_entry;
1764        struct xt_table *new_table;
1765
1766        newinfo = xt_alloc_table_info(repl->size);
1767        if (!newinfo) {
1768                ret = -ENOMEM;
1769                goto out;
1770        }
1771
1772        /* choose the copy on our node/cpu */
1773        loc_cpu_entry = newinfo->entries[raw_smp_processor_id()];
1774        memcpy(loc_cpu_entry, repl->entries, repl->size);
1775
1776        ret = translate_table(newinfo, loc_cpu_entry, repl);
1777        duprintf("arpt_register_table: translate table gives %d\n", ret);
1778        if (ret != 0)
1779                goto out_free;
1780
1781        new_table = xt_register_table(net, table, &bootstrap, newinfo);
1782        if (IS_ERR(new_table)) {
1783                ret = PTR_ERR(new_table);
1784                goto out_free;
1785        }
1786        return new_table;
1787
1788out_free:
1789        xt_free_table_info(newinfo);
1790out:
1791        return ERR_PTR(ret);
1792}
1793
1794void arpt_unregister_table(struct xt_table *table)
1795{
1796        struct xt_table_info *private;
1797        void *loc_cpu_entry;
1798        struct module *table_owner = table->me;
1799        struct arpt_entry *iter;
1800
1801        private = xt_unregister_table(table);
1802
1803        /* Decrease module usage counts and free resources */
1804        loc_cpu_entry = private->entries[raw_smp_processor_id()];
1805        xt_entry_foreach(iter, loc_cpu_entry, private->size)
1806                cleanup_entry(iter);
1807        if (private->number > private->initial_entries)
1808                module_put(table_owner);
1809        xt_free_table_info(private);
1810}
1811
1812/* The built-in targets: standard (NULL) and error. */
1813static struct xt_target arpt_builtin_tg[] __read_mostly = {
1814        {
1815                .name             = XT_STANDARD_TARGET,
1816                .targetsize       = sizeof(int),
1817                .family           = NFPROTO_ARP,
1818#ifdef CONFIG_COMPAT
1819                .compatsize       = sizeof(compat_int_t),
1820                .compat_from_user = compat_standard_from_user,
1821                .compat_to_user   = compat_standard_to_user,
1822#endif
1823        },
1824        {
1825                .name             = XT_ERROR_TARGET,
1826                .target           = arpt_error,
1827                .targetsize       = XT_FUNCTION_MAXNAMELEN,
1828                .family           = NFPROTO_ARP,
1829        },
1830};
1831
1832static struct nf_sockopt_ops arpt_sockopts = {
1833        .pf             = PF_INET,
1834        .set_optmin     = ARPT_BASE_CTL,
1835        .set_optmax     = ARPT_SO_SET_MAX+1,
1836        .set            = do_arpt_set_ctl,
1837#ifdef CONFIG_COMPAT
1838        .compat_set     = compat_do_arpt_set_ctl,
1839#endif
1840        .get_optmin     = ARPT_BASE_CTL,
1841        .get_optmax     = ARPT_SO_GET_MAX+1,
1842        .get            = do_arpt_get_ctl,
1843#ifdef CONFIG_COMPAT
1844        .compat_get     = compat_do_arpt_get_ctl,
1845#endif
1846        .owner          = THIS_MODULE,
1847};
1848
1849static int __net_init arp_tables_net_init(struct net *net)
1850{
1851        return xt_proto_init(net, NFPROTO_ARP);
1852}
1853
1854static void __net_exit arp_tables_net_exit(struct net *net)
1855{
1856        xt_proto_fini(net, NFPROTO_ARP);
1857}
1858
1859static struct pernet_operations arp_tables_net_ops = {
1860        .init = arp_tables_net_init,
1861        .exit = arp_tables_net_exit,
1862};
1863
1864static int __init arp_tables_init(void)
1865{
1866        int ret;
1867
1868        ret = register_pernet_subsys(&arp_tables_net_ops);
1869        if (ret < 0)
1870                goto err1;
1871
1872        /* Noone else will be downing sem now, so we won't sleep */
1873        ret = xt_register_targets(arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg));
1874        if (ret < 0)
1875                goto err2;
1876
1877        /* Register setsockopt */
1878        ret = nf_register_sockopt(&arpt_sockopts);
1879        if (ret < 0)
1880                goto err4;
1881
1882        printk(KERN_INFO "arp_tables: (C) 2002 David S. Miller\n");
1883        return 0;
1884
1885err4:
1886        xt_unregister_targets(arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg));
1887err2:
1888        unregister_pernet_subsys(&arp_tables_net_ops);
1889err1:
1890        return ret;
1891}
1892
1893static void __exit arp_tables_fini(void)
1894{
1895        nf_unregister_sockopt(&arpt_sockopts);
1896        xt_unregister_targets(arpt_builtin_tg, ARRAY_SIZE(arpt_builtin_tg));
1897        unregister_pernet_subsys(&arp_tables_net_ops);
1898}
1899
1900EXPORT_SYMBOL(arpt_register_table);
1901EXPORT_SYMBOL(arpt_unregister_table);
1902EXPORT_SYMBOL(arpt_do_table);
1903
1904module_init(arp_tables_init);
1905module_exit(arp_tables_fini);
1906