linux/net/netlabel/netlabel_domainhash.c
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   1/*
   2 * NetLabel Domain Hash Table
   3 *
   4 * This file manages the domain hash table that NetLabel uses to determine
   5 * which network labeling protocol to use for a given domain.  The NetLabel
   6 * system manages static and dynamic label mappings for network protocols such
   7 * as CIPSO and RIPSO.
   8 *
   9 * Author: Paul Moore <paul@paul-moore.com>
  10 *
  11 */
  12
  13/*
  14 * (c) Copyright Hewlett-Packard Development Company, L.P., 2006, 2008
  15 *
  16 * This program is free software;  you can redistribute it and/or modify
  17 * it under the terms of the GNU General Public License as published by
  18 * the Free Software Foundation; either version 2 of the License, or
  19 * (at your option) any later version.
  20 *
  21 * This program is distributed in the hope that it will be useful,
  22 * but WITHOUT ANY WARRANTY;  without even the implied warranty of
  23 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
  24 * the GNU General Public License for more details.
  25 *
  26 * You should have received a copy of the GNU General Public License
  27 * along with this program;  if not, write to the Free Software
  28 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  29 *
  30 */
  31
  32#include <linux/types.h>
  33#include <linux/rculist.h>
  34#include <linux/skbuff.h>
  35#include <linux/spinlock.h>
  36#include <linux/string.h>
  37#include <linux/audit.h>
  38#include <linux/slab.h>
  39#include <net/netlabel.h>
  40#include <net/cipso_ipv4.h>
  41#include <asm/bug.h>
  42
  43#include "netlabel_mgmt.h"
  44#include "netlabel_addrlist.h"
  45#include "netlabel_domainhash.h"
  46#include "netlabel_user.h"
  47
  48struct netlbl_domhsh_tbl {
  49        struct list_head *tbl;
  50        u32 size;
  51};
  52
  53/* Domain hash table */
  54/* updates should be so rare that having one spinlock for the entire hash table
  55 * should be okay */
  56static DEFINE_SPINLOCK(netlbl_domhsh_lock);
  57#define netlbl_domhsh_rcu_deref(p) \
  58        rcu_dereference_check(p, lockdep_is_held(&netlbl_domhsh_lock))
  59static struct netlbl_domhsh_tbl *netlbl_domhsh = NULL;
  60static struct netlbl_dom_map *netlbl_domhsh_def = NULL;
  61
  62/*
  63 * Domain Hash Table Helper Functions
  64 */
  65
  66/**
  67 * netlbl_domhsh_free_entry - Frees a domain hash table entry
  68 * @entry: the entry's RCU field
  69 *
  70 * Description:
  71 * This function is designed to be used as a callback to the call_rcu()
  72 * function so that the memory allocated to a hash table entry can be released
  73 * safely.
  74 *
  75 */
  76static void netlbl_domhsh_free_entry(struct rcu_head *entry)
  77{
  78        struct netlbl_dom_map *ptr;
  79        struct netlbl_af4list *iter4;
  80        struct netlbl_af4list *tmp4;
  81#if IS_ENABLED(CONFIG_IPV6)
  82        struct netlbl_af6list *iter6;
  83        struct netlbl_af6list *tmp6;
  84#endif /* IPv6 */
  85
  86        ptr = container_of(entry, struct netlbl_dom_map, rcu);
  87        if (ptr->def.type == NETLBL_NLTYPE_ADDRSELECT) {
  88                netlbl_af4list_foreach_safe(iter4, tmp4,
  89                                            &ptr->def.addrsel->list4) {
  90                        netlbl_af4list_remove_entry(iter4);
  91                        kfree(netlbl_domhsh_addr4_entry(iter4));
  92                }
  93#if IS_ENABLED(CONFIG_IPV6)
  94                netlbl_af6list_foreach_safe(iter6, tmp6,
  95                                            &ptr->def.addrsel->list6) {
  96                        netlbl_af6list_remove_entry(iter6);
  97                        kfree(netlbl_domhsh_addr6_entry(iter6));
  98                }
  99#endif /* IPv6 */
 100        }
 101        kfree(ptr->domain);
 102        kfree(ptr);
 103}
 104
 105/**
 106 * netlbl_domhsh_hash - Hashing function for the domain hash table
 107 * @domain: the domain name to hash
 108 *
 109 * Description:
 110 * This is the hashing function for the domain hash table, it returns the
 111 * correct bucket number for the domain.  The caller is responsible for
 112 * ensuring that the hash table is protected with either a RCU read lock or the
 113 * hash table lock.
 114 *
 115 */
 116static u32 netlbl_domhsh_hash(const char *key)
 117{
 118        u32 iter;
 119        u32 val;
 120        u32 len;
 121
 122        /* This is taken (with slight modification) from
 123         * security/selinux/ss/symtab.c:symhash() */
 124
 125        for (iter = 0, val = 0, len = strlen(key); iter < len; iter++)
 126                val = (val << 4 | (val >> (8 * sizeof(u32) - 4))) ^ key[iter];
 127        return val & (netlbl_domhsh_rcu_deref(netlbl_domhsh)->size - 1);
 128}
 129
 130/**
 131 * netlbl_domhsh_search - Search for a domain entry
 132 * @domain: the domain
 133 *
 134 * Description:
 135 * Searches the domain hash table and returns a pointer to the hash table
 136 * entry if found, otherwise NULL is returned.  The caller is responsible for
 137 * ensuring that the hash table is protected with either a RCU read lock or the
 138 * hash table lock.
 139 *
 140 */
 141static struct netlbl_dom_map *netlbl_domhsh_search(const char *domain)
 142{
 143        u32 bkt;
 144        struct list_head *bkt_list;
 145        struct netlbl_dom_map *iter;
 146
 147        if (domain != NULL) {
 148                bkt = netlbl_domhsh_hash(domain);
 149                bkt_list = &netlbl_domhsh_rcu_deref(netlbl_domhsh)->tbl[bkt];
 150                list_for_each_entry_rcu(iter, bkt_list, list)
 151                        if (iter->valid && strcmp(iter->domain, domain) == 0)
 152                                return iter;
 153        }
 154
 155        return NULL;
 156}
 157
 158/**
 159 * netlbl_domhsh_search_def - Search for a domain entry
 160 * @domain: the domain
 161 * @def: return default if no match is found
 162 *
 163 * Description:
 164 * Searches the domain hash table and returns a pointer to the hash table
 165 * entry if an exact match is found, if an exact match is not present in the
 166 * hash table then the default entry is returned if valid otherwise NULL is
 167 * returned.  The caller is responsible ensuring that the hash table is
 168 * protected with either a RCU read lock or the hash table lock.
 169 *
 170 */
 171static struct netlbl_dom_map *netlbl_domhsh_search_def(const char *domain)
 172{
 173        struct netlbl_dom_map *entry;
 174
 175        entry = netlbl_domhsh_search(domain);
 176        if (entry == NULL) {
 177                entry = netlbl_domhsh_rcu_deref(netlbl_domhsh_def);
 178                if (entry != NULL && !entry->valid)
 179                        entry = NULL;
 180        }
 181
 182        return entry;
 183}
 184
 185/**
 186 * netlbl_domhsh_audit_add - Generate an audit entry for an add event
 187 * @entry: the entry being added
 188 * @addr4: the IPv4 address information
 189 * @addr6: the IPv6 address information
 190 * @result: the result code
 191 * @audit_info: NetLabel audit information
 192 *
 193 * Description:
 194 * Generate an audit record for adding a new NetLabel/LSM mapping entry with
 195 * the given information.  Caller is responsible for holding the necessary
 196 * locks.
 197 *
 198 */
 199static void netlbl_domhsh_audit_add(struct netlbl_dom_map *entry,
 200                                    struct netlbl_af4list *addr4,
 201                                    struct netlbl_af6list *addr6,
 202                                    int result,
 203                                    struct netlbl_audit *audit_info)
 204{
 205        struct audit_buffer *audit_buf;
 206        struct cipso_v4_doi *cipsov4 = NULL;
 207        u32 type;
 208
 209        audit_buf = netlbl_audit_start_common(AUDIT_MAC_MAP_ADD, audit_info);
 210        if (audit_buf != NULL) {
 211                audit_log_format(audit_buf, " nlbl_domain=%s",
 212                                 entry->domain ? entry->domain : "(default)");
 213                if (addr4 != NULL) {
 214                        struct netlbl_domaddr4_map *map4;
 215                        map4 = netlbl_domhsh_addr4_entry(addr4);
 216                        type = map4->def.type;
 217                        cipsov4 = map4->def.cipso;
 218                        netlbl_af4list_audit_addr(audit_buf, 0, NULL,
 219                                                  addr4->addr, addr4->mask);
 220#if IS_ENABLED(CONFIG_IPV6)
 221                } else if (addr6 != NULL) {
 222                        struct netlbl_domaddr6_map *map6;
 223                        map6 = netlbl_domhsh_addr6_entry(addr6);
 224                        type = map6->def.type;
 225                        netlbl_af6list_audit_addr(audit_buf, 0, NULL,
 226                                                  &addr6->addr, &addr6->mask);
 227#endif /* IPv6 */
 228                } else {
 229                        type = entry->def.type;
 230                        cipsov4 = entry->def.cipso;
 231                }
 232                switch (type) {
 233                case NETLBL_NLTYPE_UNLABELED:
 234                        audit_log_format(audit_buf, " nlbl_protocol=unlbl");
 235                        break;
 236                case NETLBL_NLTYPE_CIPSOV4:
 237                        BUG_ON(cipsov4 == NULL);
 238                        audit_log_format(audit_buf,
 239                                         " nlbl_protocol=cipsov4 cipso_doi=%u",
 240                                         cipsov4->doi);
 241                        break;
 242                }
 243                audit_log_format(audit_buf, " res=%u", result == 0 ? 1 : 0);
 244                audit_log_end(audit_buf);
 245        }
 246}
 247
 248/**
 249 * netlbl_domhsh_validate - Validate a new domain mapping entry
 250 * @entry: the entry to validate
 251 *
 252 * This function validates the new domain mapping entry to ensure that it is
 253 * a valid entry.  Returns zero on success, negative values on failure.
 254 *
 255 */
 256static int netlbl_domhsh_validate(const struct netlbl_dom_map *entry)
 257{
 258        struct netlbl_af4list *iter4;
 259        struct netlbl_domaddr4_map *map4;
 260#if IS_ENABLED(CONFIG_IPV6)
 261        struct netlbl_af6list *iter6;
 262        struct netlbl_domaddr6_map *map6;
 263#endif /* IPv6 */
 264
 265        if (entry == NULL)
 266                return -EINVAL;
 267
 268        switch (entry->def.type) {
 269        case NETLBL_NLTYPE_UNLABELED:
 270                if (entry->def.cipso != NULL || entry->def.addrsel != NULL)
 271                        return -EINVAL;
 272                break;
 273        case NETLBL_NLTYPE_CIPSOV4:
 274                if (entry->def.cipso == NULL)
 275                        return -EINVAL;
 276                break;
 277        case NETLBL_NLTYPE_ADDRSELECT:
 278                netlbl_af4list_foreach(iter4, &entry->def.addrsel->list4) {
 279                        map4 = netlbl_domhsh_addr4_entry(iter4);
 280                        switch (map4->def.type) {
 281                        case NETLBL_NLTYPE_UNLABELED:
 282                                if (map4->def.cipso != NULL)
 283                                        return -EINVAL;
 284                                break;
 285                        case NETLBL_NLTYPE_CIPSOV4:
 286                                if (map4->def.cipso == NULL)
 287                                        return -EINVAL;
 288                                break;
 289                        default:
 290                                return -EINVAL;
 291                        }
 292                }
 293#if IS_ENABLED(CONFIG_IPV6)
 294                netlbl_af6list_foreach(iter6, &entry->def.addrsel->list6) {
 295                        map6 = netlbl_domhsh_addr6_entry(iter6);
 296                        switch (map6->def.type) {
 297                        case NETLBL_NLTYPE_UNLABELED:
 298                                break;
 299                        default:
 300                                return -EINVAL;
 301                        }
 302                }
 303#endif /* IPv6 */
 304                break;
 305        default:
 306                return -EINVAL;
 307        }
 308
 309        return 0;
 310}
 311
 312/*
 313 * Domain Hash Table Functions
 314 */
 315
 316/**
 317 * netlbl_domhsh_init - Init for the domain hash
 318 * @size: the number of bits to use for the hash buckets
 319 *
 320 * Description:
 321 * Initializes the domain hash table, should be called only by
 322 * netlbl_user_init() during initialization.  Returns zero on success, non-zero
 323 * values on error.
 324 *
 325 */
 326int __init netlbl_domhsh_init(u32 size)
 327{
 328        u32 iter;
 329        struct netlbl_domhsh_tbl *hsh_tbl;
 330
 331        if (size == 0)
 332                return -EINVAL;
 333
 334        hsh_tbl = kmalloc(sizeof(*hsh_tbl), GFP_KERNEL);
 335        if (hsh_tbl == NULL)
 336                return -ENOMEM;
 337        hsh_tbl->size = 1 << size;
 338        hsh_tbl->tbl = kcalloc(hsh_tbl->size,
 339                               sizeof(struct list_head),
 340                               GFP_KERNEL);
 341        if (hsh_tbl->tbl == NULL) {
 342                kfree(hsh_tbl);
 343                return -ENOMEM;
 344        }
 345        for (iter = 0; iter < hsh_tbl->size; iter++)
 346                INIT_LIST_HEAD(&hsh_tbl->tbl[iter]);
 347
 348        spin_lock(&netlbl_domhsh_lock);
 349        rcu_assign_pointer(netlbl_domhsh, hsh_tbl);
 350        spin_unlock(&netlbl_domhsh_lock);
 351
 352        return 0;
 353}
 354
 355/**
 356 * netlbl_domhsh_add - Adds a entry to the domain hash table
 357 * @entry: the entry to add
 358 * @audit_info: NetLabel audit information
 359 *
 360 * Description:
 361 * Adds a new entry to the domain hash table and handles any updates to the
 362 * lower level protocol handler (i.e. CIPSO).  Returns zero on success,
 363 * negative on failure.
 364 *
 365 */
 366int netlbl_domhsh_add(struct netlbl_dom_map *entry,
 367                      struct netlbl_audit *audit_info)
 368{
 369        int ret_val = 0;
 370        struct netlbl_dom_map *entry_old;
 371        struct netlbl_af4list *iter4;
 372        struct netlbl_af4list *tmp4;
 373#if IS_ENABLED(CONFIG_IPV6)
 374        struct netlbl_af6list *iter6;
 375        struct netlbl_af6list *tmp6;
 376#endif /* IPv6 */
 377
 378        ret_val = netlbl_domhsh_validate(entry);
 379        if (ret_val != 0)
 380                return ret_val;
 381
 382        /* XXX - we can remove this RCU read lock as the spinlock protects the
 383         *       entire function, but before we do we need to fixup the
 384         *       netlbl_af[4,6]list RCU functions to do "the right thing" with
 385         *       respect to rcu_dereference() when only a spinlock is held. */
 386        rcu_read_lock();
 387        spin_lock(&netlbl_domhsh_lock);
 388        if (entry->domain != NULL)
 389                entry_old = netlbl_domhsh_search(entry->domain);
 390        else
 391                entry_old = netlbl_domhsh_search_def(entry->domain);
 392        if (entry_old == NULL) {
 393                entry->valid = 1;
 394
 395                if (entry->domain != NULL) {
 396                        u32 bkt = netlbl_domhsh_hash(entry->domain);
 397                        list_add_tail_rcu(&entry->list,
 398                                    &rcu_dereference(netlbl_domhsh)->tbl[bkt]);
 399                } else {
 400                        INIT_LIST_HEAD(&entry->list);
 401                        rcu_assign_pointer(netlbl_domhsh_def, entry);
 402                }
 403
 404                if (entry->def.type == NETLBL_NLTYPE_ADDRSELECT) {
 405                        netlbl_af4list_foreach_rcu(iter4,
 406                                                   &entry->def.addrsel->list4)
 407                                netlbl_domhsh_audit_add(entry, iter4, NULL,
 408                                                        ret_val, audit_info);
 409#if IS_ENABLED(CONFIG_IPV6)
 410                        netlbl_af6list_foreach_rcu(iter6,
 411                                                   &entry->def.addrsel->list6)
 412                                netlbl_domhsh_audit_add(entry, NULL, iter6,
 413                                                        ret_val, audit_info);
 414#endif /* IPv6 */
 415                } else
 416                        netlbl_domhsh_audit_add(entry, NULL, NULL,
 417                                                ret_val, audit_info);
 418        } else if (entry_old->def.type == NETLBL_NLTYPE_ADDRSELECT &&
 419                   entry->def.type == NETLBL_NLTYPE_ADDRSELECT) {
 420                struct list_head *old_list4;
 421                struct list_head *old_list6;
 422
 423                old_list4 = &entry_old->def.addrsel->list4;
 424                old_list6 = &entry_old->def.addrsel->list6;
 425
 426                /* we only allow the addition of address selectors if all of
 427                 * the selectors do not exist in the existing domain map */
 428                netlbl_af4list_foreach_rcu(iter4, &entry->def.addrsel->list4)
 429                        if (netlbl_af4list_search_exact(iter4->addr,
 430                                                        iter4->mask,
 431                                                        old_list4)) {
 432                                ret_val = -EEXIST;
 433                                goto add_return;
 434                        }
 435#if IS_ENABLED(CONFIG_IPV6)
 436                netlbl_af6list_foreach_rcu(iter6, &entry->def.addrsel->list6)
 437                        if (netlbl_af6list_search_exact(&iter6->addr,
 438                                                        &iter6->mask,
 439                                                        old_list6)) {
 440                                ret_val = -EEXIST;
 441                                goto add_return;
 442                        }
 443#endif /* IPv6 */
 444
 445                netlbl_af4list_foreach_safe(iter4, tmp4,
 446                                            &entry->def.addrsel->list4) {
 447                        netlbl_af4list_remove_entry(iter4);
 448                        iter4->valid = 1;
 449                        ret_val = netlbl_af4list_add(iter4, old_list4);
 450                        netlbl_domhsh_audit_add(entry_old, iter4, NULL,
 451                                                ret_val, audit_info);
 452                        if (ret_val != 0)
 453                                goto add_return;
 454                }
 455#if IS_ENABLED(CONFIG_IPV6)
 456                netlbl_af6list_foreach_safe(iter6, tmp6,
 457                                            &entry->def.addrsel->list6) {
 458                        netlbl_af6list_remove_entry(iter6);
 459                        iter6->valid = 1;
 460                        ret_val = netlbl_af6list_add(iter6, old_list6);
 461                        netlbl_domhsh_audit_add(entry_old, NULL, iter6,
 462                                                ret_val, audit_info);
 463                        if (ret_val != 0)
 464                                goto add_return;
 465                }
 466#endif /* IPv6 */
 467        } else
 468                ret_val = -EINVAL;
 469
 470add_return:
 471        spin_unlock(&netlbl_domhsh_lock);
 472        rcu_read_unlock();
 473        return ret_val;
 474}
 475
 476/**
 477 * netlbl_domhsh_add_default - Adds the default entry to the domain hash table
 478 * @entry: the entry to add
 479 * @audit_info: NetLabel audit information
 480 *
 481 * Description:
 482 * Adds a new default entry to the domain hash table and handles any updates
 483 * to the lower level protocol handler (i.e. CIPSO).  Returns zero on success,
 484 * negative on failure.
 485 *
 486 */
 487int netlbl_domhsh_add_default(struct netlbl_dom_map *entry,
 488                              struct netlbl_audit *audit_info)
 489{
 490        return netlbl_domhsh_add(entry, audit_info);
 491}
 492
 493/**
 494 * netlbl_domhsh_remove_entry - Removes a given entry from the domain table
 495 * @entry: the entry to remove
 496 * @audit_info: NetLabel audit information
 497 *
 498 * Description:
 499 * Removes an entry from the domain hash table and handles any updates to the
 500 * lower level protocol handler (i.e. CIPSO).  Caller is responsible for
 501 * ensuring that the RCU read lock is held.  Returns zero on success, negative
 502 * on failure.
 503 *
 504 */
 505int netlbl_domhsh_remove_entry(struct netlbl_dom_map *entry,
 506                               struct netlbl_audit *audit_info)
 507{
 508        int ret_val = 0;
 509        struct audit_buffer *audit_buf;
 510
 511        if (entry == NULL)
 512                return -ENOENT;
 513
 514        spin_lock(&netlbl_domhsh_lock);
 515        if (entry->valid) {
 516                entry->valid = 0;
 517                if (entry != rcu_dereference(netlbl_domhsh_def))
 518                        list_del_rcu(&entry->list);
 519                else
 520                        RCU_INIT_POINTER(netlbl_domhsh_def, NULL);
 521        } else
 522                ret_val = -ENOENT;
 523        spin_unlock(&netlbl_domhsh_lock);
 524
 525        audit_buf = netlbl_audit_start_common(AUDIT_MAC_MAP_DEL, audit_info);
 526        if (audit_buf != NULL) {
 527                audit_log_format(audit_buf,
 528                                 " nlbl_domain=%s res=%u",
 529                                 entry->domain ? entry->domain : "(default)",
 530                                 ret_val == 0 ? 1 : 0);
 531                audit_log_end(audit_buf);
 532        }
 533
 534        if (ret_val == 0) {
 535                struct netlbl_af4list *iter4;
 536                struct netlbl_domaddr4_map *map4;
 537
 538                switch (entry->def.type) {
 539                case NETLBL_NLTYPE_ADDRSELECT:
 540                        netlbl_af4list_foreach_rcu(iter4,
 541                                             &entry->def.addrsel->list4) {
 542                                map4 = netlbl_domhsh_addr4_entry(iter4);
 543                                cipso_v4_doi_putdef(map4->def.cipso);
 544                        }
 545                        /* no need to check the IPv6 list since we currently
 546                         * support only unlabeled protocols for IPv6 */
 547                        break;
 548                case NETLBL_NLTYPE_CIPSOV4:
 549                        cipso_v4_doi_putdef(entry->def.cipso);
 550                        break;
 551                }
 552                call_rcu(&entry->rcu, netlbl_domhsh_free_entry);
 553        }
 554
 555        return ret_val;
 556}
 557
 558/**
 559 * netlbl_domhsh_remove_af4 - Removes an address selector entry
 560 * @domain: the domain
 561 * @addr: IPv4 address
 562 * @mask: IPv4 address mask
 563 * @audit_info: NetLabel audit information
 564 *
 565 * Description:
 566 * Removes an individual address selector from a domain mapping and potentially
 567 * the entire mapping if it is empty.  Returns zero on success, negative values
 568 * on failure.
 569 *
 570 */
 571int netlbl_domhsh_remove_af4(const char *domain,
 572                             const struct in_addr *addr,
 573                             const struct in_addr *mask,
 574                             struct netlbl_audit *audit_info)
 575{
 576        struct netlbl_dom_map *entry_map;
 577        struct netlbl_af4list *entry_addr;
 578        struct netlbl_af4list *iter4;
 579#if IS_ENABLED(CONFIG_IPV6)
 580        struct netlbl_af6list *iter6;
 581#endif /* IPv6 */
 582        struct netlbl_domaddr4_map *entry;
 583
 584        rcu_read_lock();
 585
 586        if (domain)
 587                entry_map = netlbl_domhsh_search(domain);
 588        else
 589                entry_map = netlbl_domhsh_search_def(domain);
 590        if (entry_map == NULL ||
 591            entry_map->def.type != NETLBL_NLTYPE_ADDRSELECT)
 592                goto remove_af4_failure;
 593
 594        spin_lock(&netlbl_domhsh_lock);
 595        entry_addr = netlbl_af4list_remove(addr->s_addr, mask->s_addr,
 596                                           &entry_map->def.addrsel->list4);
 597        spin_unlock(&netlbl_domhsh_lock);
 598
 599        if (entry_addr == NULL)
 600                goto remove_af4_failure;
 601        netlbl_af4list_foreach_rcu(iter4, &entry_map->def.addrsel->list4)
 602                goto remove_af4_single_addr;
 603#if IS_ENABLED(CONFIG_IPV6)
 604        netlbl_af6list_foreach_rcu(iter6, &entry_map->def.addrsel->list6)
 605                goto remove_af4_single_addr;
 606#endif /* IPv6 */
 607        /* the domain mapping is empty so remove it from the mapping table */
 608        netlbl_domhsh_remove_entry(entry_map, audit_info);
 609
 610remove_af4_single_addr:
 611        rcu_read_unlock();
 612        /* yick, we can't use call_rcu here because we don't have a rcu head
 613         * pointer but hopefully this should be a rare case so the pause
 614         * shouldn't be a problem */
 615        synchronize_rcu();
 616        entry = netlbl_domhsh_addr4_entry(entry_addr);
 617        cipso_v4_doi_putdef(entry->def.cipso);
 618        kfree(entry);
 619        return 0;
 620
 621remove_af4_failure:
 622        rcu_read_unlock();
 623        return -ENOENT;
 624}
 625
 626/**
 627 * netlbl_domhsh_remove - Removes an entry from the domain hash table
 628 * @domain: the domain to remove
 629 * @audit_info: NetLabel audit information
 630 *
 631 * Description:
 632 * Removes an entry from the domain hash table and handles any updates to the
 633 * lower level protocol handler (i.e. CIPSO).  Returns zero on success,
 634 * negative on failure.
 635 *
 636 */
 637int netlbl_domhsh_remove(const char *domain, struct netlbl_audit *audit_info)
 638{
 639        int ret_val;
 640        struct netlbl_dom_map *entry;
 641
 642        rcu_read_lock();
 643        if (domain)
 644                entry = netlbl_domhsh_search(domain);
 645        else
 646                entry = netlbl_domhsh_search_def(domain);
 647        ret_val = netlbl_domhsh_remove_entry(entry, audit_info);
 648        rcu_read_unlock();
 649
 650        return ret_val;
 651}
 652
 653/**
 654 * netlbl_domhsh_remove_default - Removes the default entry from the table
 655 * @audit_info: NetLabel audit information
 656 *
 657 * Description:
 658 * Removes/resets the default entry for the domain hash table and handles any
 659 * updates to the lower level protocol handler (i.e. CIPSO).  Returns zero on
 660 * success, non-zero on failure.
 661 *
 662 */
 663int netlbl_domhsh_remove_default(struct netlbl_audit *audit_info)
 664{
 665        return netlbl_domhsh_remove(NULL, audit_info);
 666}
 667
 668/**
 669 * netlbl_domhsh_getentry - Get an entry from the domain hash table
 670 * @domain: the domain name to search for
 671 *
 672 * Description:
 673 * Look through the domain hash table searching for an entry to match @domain,
 674 * return a pointer to a copy of the entry or NULL.  The caller is responsible
 675 * for ensuring that rcu_read_[un]lock() is called.
 676 *
 677 */
 678struct netlbl_dom_map *netlbl_domhsh_getentry(const char *domain)
 679{
 680        return netlbl_domhsh_search_def(domain);
 681}
 682
 683/**
 684 * netlbl_domhsh_getentry_af4 - Get an entry from the domain hash table
 685 * @domain: the domain name to search for
 686 * @addr: the IP address to search for
 687 *
 688 * Description:
 689 * Look through the domain hash table searching for an entry to match @domain
 690 * and @addr, return a pointer to a copy of the entry or NULL.  The caller is
 691 * responsible for ensuring that rcu_read_[un]lock() is called.
 692 *
 693 */
 694struct netlbl_dommap_def *netlbl_domhsh_getentry_af4(const char *domain,
 695                                                     __be32 addr)
 696{
 697        struct netlbl_dom_map *dom_iter;
 698        struct netlbl_af4list *addr_iter;
 699
 700        dom_iter = netlbl_domhsh_search_def(domain);
 701        if (dom_iter == NULL)
 702                return NULL;
 703
 704        if (dom_iter->def.type != NETLBL_NLTYPE_ADDRSELECT)
 705                return &dom_iter->def;
 706        addr_iter = netlbl_af4list_search(addr, &dom_iter->def.addrsel->list4);
 707        if (addr_iter == NULL)
 708                return NULL;
 709        return &(netlbl_domhsh_addr4_entry(addr_iter)->def);
 710}
 711
 712#if IS_ENABLED(CONFIG_IPV6)
 713/**
 714 * netlbl_domhsh_getentry_af6 - Get an entry from the domain hash table
 715 * @domain: the domain name to search for
 716 * @addr: the IP address to search for
 717 *
 718 * Description:
 719 * Look through the domain hash table searching for an entry to match @domain
 720 * and @addr, return a pointer to a copy of the entry or NULL.  The caller is
 721 * responsible for ensuring that rcu_read_[un]lock() is called.
 722 *
 723 */
 724struct netlbl_dommap_def *netlbl_domhsh_getentry_af6(const char *domain,
 725                                                   const struct in6_addr *addr)
 726{
 727        struct netlbl_dom_map *dom_iter;
 728        struct netlbl_af6list *addr_iter;
 729
 730        dom_iter = netlbl_domhsh_search_def(domain);
 731        if (dom_iter == NULL)
 732                return NULL;
 733
 734        if (dom_iter->def.type != NETLBL_NLTYPE_ADDRSELECT)
 735                return &dom_iter->def;
 736        addr_iter = netlbl_af6list_search(addr, &dom_iter->def.addrsel->list6);
 737        if (addr_iter == NULL)
 738                return NULL;
 739        return &(netlbl_domhsh_addr6_entry(addr_iter)->def);
 740}
 741#endif /* IPv6 */
 742
 743/**
 744 * netlbl_domhsh_walk - Iterate through the domain mapping hash table
 745 * @skip_bkt: the number of buckets to skip at the start
 746 * @skip_chain: the number of entries to skip in the first iterated bucket
 747 * @callback: callback for each entry
 748 * @cb_arg: argument for the callback function
 749 *
 750 * Description:
 751 * Interate over the domain mapping hash table, skipping the first @skip_bkt
 752 * buckets and @skip_chain entries.  For each entry in the table call
 753 * @callback, if @callback returns a negative value stop 'walking' through the
 754 * table and return.  Updates the values in @skip_bkt and @skip_chain on
 755 * return.  Returns zero on success, negative values on failure.
 756 *
 757 */
 758int netlbl_domhsh_walk(u32 *skip_bkt,
 759                     u32 *skip_chain,
 760                     int (*callback) (struct netlbl_dom_map *entry, void *arg),
 761                     void *cb_arg)
 762{
 763        int ret_val = -ENOENT;
 764        u32 iter_bkt;
 765        struct list_head *iter_list;
 766        struct netlbl_dom_map *iter_entry;
 767        u32 chain_cnt = 0;
 768
 769        rcu_read_lock();
 770        for (iter_bkt = *skip_bkt;
 771             iter_bkt < rcu_dereference(netlbl_domhsh)->size;
 772             iter_bkt++, chain_cnt = 0) {
 773                iter_list = &rcu_dereference(netlbl_domhsh)->tbl[iter_bkt];
 774                list_for_each_entry_rcu(iter_entry, iter_list, list)
 775                        if (iter_entry->valid) {
 776                                if (chain_cnt++ < *skip_chain)
 777                                        continue;
 778                                ret_val = callback(iter_entry, cb_arg);
 779                                if (ret_val < 0) {
 780                                        chain_cnt--;
 781                                        goto walk_return;
 782                                }
 783                        }
 784        }
 785
 786walk_return:
 787        rcu_read_unlock();
 788        *skip_bkt = iter_bkt;
 789        *skip_chain = chain_cnt;
 790        return ret_val;
 791}
 792
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