security/tomoyo/domain.c

   1 /*
   2  * security/tomoyo/domain.c
   3  *
   4  * Domain transition functions for TOMOYO.
   5  *
   6  * Copyright (C) 2005-2010  NTT DATA CORPORATION
   7  */
   8
   9 #include "common.h"
  10 #include <linux/binfmts.h>
  11 #include <linux/slab.h>
  12
  13 /* Variables definitions.*/
  14
  15 /* The initial domain. */
  16 struct tomoyo_domain_info tomoyo_kernel_domain;
  17
  18 /**
  19  * tomoyo_update_policy - Update an entry for exception policy.
  20  *
  21  * @new_entry:       Pointer to "struct tomoyo_acl_info".
  22  * @size:            Size of @new_entry in bytes.
  23  * @param:           Pointer to "struct tomoyo_acl_param".
  24  * @check_duplicate: Callback function to find duplicated entry.
  25  *
  26  * Returns 0 on success, negative value otherwise.
  27  *
  28  * Caller holds tomoyo_read_lock().
  29  */
  30 int tomoyo_update_policy(struct tomoyo_acl_head *new_entry, const int size,
  31                          struct tomoyo_acl_param *param,
  32                          bool (*check_duplicate) (const struct tomoyo_acl_head
  33                                                   *,
  34                                                   const struct tomoyo_acl_head
  35                                                   *))
  36 {
  37         int error = param->is_delete ? -ENOENT : -ENOMEM;
  38         struct tomoyo_acl_head *entry;
  39         struct list_head *list = param->list;
  40
  41         if (mutex_lock_interruptible(&tomoyo_policy_lock))
  42                 return -ENOMEM;
  43         list_for_each_entry_rcu(entry, list, list) {
  44                 if (!check_duplicate(entry, new_entry))
  45                         continue;
  46                 entry->is_deleted = param->is_delete;
  47                 error = 0;
  48                 break;
  49         }
  50         if (error && !param->is_delete) {
  51                 entry = tomoyo_commit_ok(new_entry, size);
  52                 if (entry) {
  53                         list_add_tail_rcu(&entry->list, list);
  54                         error = 0;
  55                 }
  56         }
  57         mutex_unlock(&tomoyo_policy_lock);
  58         return error;
  59 }
  60
  61 /**
  62  * tomoyo_same_acl_head - Check for duplicated "struct tomoyo_acl_info" entry.
  63  *
  64  * @a: Pointer to "struct tomoyo_acl_info".
  65  * @b: Pointer to "struct tomoyo_acl_info".
  66  *
  67  * Returns true if @a == @b, false otherwise.
  68  */
  69 static inline bool tomoyo_same_acl_head(const struct tomoyo_acl_info *a,
  70                                         const struct tomoyo_acl_info *b)
  71 {
  72         return a->type == b->type && a->cond == b->cond;
  73 }
  74
  75 /**
  76  * tomoyo_update_domain - Update an entry for domain policy.
  77  *
  78  * @new_entry:       Pointer to "struct tomoyo_acl_info".
  79  * @size:            Size of @new_entry in bytes.
  80  * @param:           Pointer to "struct tomoyo_acl_param".
  81  * @check_duplicate: Callback function to find duplicated entry.
  82  * @merge_duplicate: Callback function to merge duplicated entry.
  83  *
  84  * Returns 0 on success, negative value otherwise.
  85  *
  86  * Caller holds tomoyo_read_lock().
  87  */
  88 int tomoyo_update_domain(struct tomoyo_acl_info *new_entry, const int size,
  89                          struct tomoyo_acl_param *param,
  90                          bool (*check_duplicate) (const struct tomoyo_acl_info
  91                                                   *,
  92                                                   const struct tomoyo_acl_info
  93                                                   *),
  94                          bool (*merge_duplicate) (struct tomoyo_acl_info *,
  95                                                   struct tomoyo_acl_info *,
  96                                                   const bool))
  97 {
  98         const bool is_delete = param->is_delete;
  99         int error = is_delete ? -ENOENT : -ENOMEM;
 100         struct tomoyo_acl_info *entry;
 101         struct list_head * const list = param->list;
 102
 103         if (param->data[0]) {
 104                 new_entry->cond = tomoyo_get_condition(param);
 105                 if (!new_entry->cond)
 106                         return -EINVAL;
 107         }
 108         if (mutex_lock_interruptible(&tomoyo_policy_lock))
 109                 goto out;
 110         list_for_each_entry_rcu(entry, list, list) {
 111                 if (!tomoyo_same_acl_head(entry, new_entry) ||
 112                     !check_duplicate(entry, new_entry))
 113                         continue;
 114                 if (merge_duplicate)
 115                         entry->is_deleted = merge_duplicate(entry, new_entry,
 116                                                             is_delete);
 117                 else
 118                         entry->is_deleted = is_delete;
 119                 error = 0;
 120                 break;
 121         }
 122         if (error && !is_delete) {
 123                 entry = tomoyo_commit_ok(new_entry, size);
 124                 if (entry) {
 125                         list_add_tail_rcu(&entry->list, list);
 126                         error = 0;
 127                 }
 128         }
 129         mutex_unlock(&tomoyo_policy_lock);
 130 out:
 131         tomoyo_put_condition(new_entry->cond);
 132         return error;
 133 }
 134
 135 /**
 136  * tomoyo_check_acl - Do permission check.
 137  *
 138  * @r:           Pointer to "struct tomoyo_request_info".
 139  * @check_entry: Callback function to check type specific parameters.
 140  *
 141  * Returns 0 on success, negative value otherwise.
 142  *
 143  * Caller holds tomoyo_read_lock().
 144  */
 145 void tomoyo_check_acl(struct tomoyo_request_info *r,
 146                       bool (*check_entry) (struct tomoyo_request_info *,
 147                                            const struct tomoyo_acl_info *))
 148 {
 149         const struct tomoyo_domain_info *domain = r->domain;
 150         struct tomoyo_acl_info *ptr;
 151         bool retried = false;
 152         const struct list_head *list = &domain->acl_info_list;
 153
 154 retry:
 155         list_for_each_entry_rcu(ptr, list, list) {
 156                 if (ptr->is_deleted || ptr->type != r->param_type)
 157                         continue;
 158                 if (!check_entry(r, ptr))
 159                         continue;
 160                 if (!tomoyo_condition(r, ptr->cond))
 161                         continue;
 162                 r->granted = true;
 163                 return;
 164         }
 165         if (!retried) {
 166                 retried = true;
 167                 list = &domain->ns->acl_group[domain->group];
 168                 goto retry;
 169         }
 170         r->granted = false;
 171 }
 172
 173 /* The list for "struct tomoyo_domain_info". */
 174 LIST_HEAD(tomoyo_domain_list);
 175
 176 /**
 177  * tomoyo_last_word - Get last component of a domainname.
 178  *
 179  * @name: Domainname to check.
 180  *
 181  * Returns the last word of @domainname.
 182  */
 183 static const char *tomoyo_last_word(const char *name)
 184 {
 185         const char *cp = strrchr(name, ' ');
 186         if (cp)
 187                 return cp + 1;
 188         return name;
 189 }
 190
 191 /**
 192  * tomoyo_same_transition_control - Check for duplicated "struct tomoyo_transition_control" entry.
 193  *
 194  * @a: Pointer to "struct tomoyo_acl_head".
 195  * @b: Pointer to "struct tomoyo_acl_head".
 196  *
 197  * Returns true if @a == @b, false otherwise.
 198  */
 199 static bool tomoyo_same_transition_control(const struct tomoyo_acl_head *a,
 200                                            const struct tomoyo_acl_head *b)
 201 {
 202         const struct tomoyo_transition_control *p1 = container_of(a,
 203                                                                   typeof(*p1),
 204                                                                   head);
 205         const struct tomoyo_transition_control *p2 = container_of(b,
 206                                                                   typeof(*p2),
 207                                                                   head);
 208         return p1->type == p2->type && p1->is_last_name == p2->is_last_name
 209                 && p1->domainname == p2->domainname
 210                 && p1->program == p2->program;
 211 }
 212
 213 /**
 214  * tomoyo_write_transition_control - Write "struct tomoyo_transition_control" list.
 215  *
 216  * @param: Pointer to "struct tomoyo_acl_param".
 217  * @type:  Type of this entry.
 218  *
 219  * Returns 0 on success, negative value otherwise.
 220  */
 221 int tomoyo_write_transition_control(struct tomoyo_acl_param *param,
 222                                     const u8 type)
 223 {
 224         struct tomoyo_transition_control e = { .type = type };
 225         int error = param->is_delete ? -ENOENT : -ENOMEM;
 226         char *program = param->data;
 227         char *domainname = strstr(program, " from ");
 228         if (domainname) {
 229                 *domainname = '\0';
 230                 domainname += 6;
 231         } else if (type == TOMOYO_TRANSITION_CONTROL_NO_KEEP ||
 232                    type == TOMOYO_TRANSITION_CONTROL_KEEP) {
 233                 domainname = program;
 234                 program = NULL;
 235         }
 236         if (program && strcmp(program, "any")) {
 237                 if (!tomoyo_correct_path(program))
 238                         return -EINVAL;
 239                 e.program = tomoyo_get_name(program);
 240                 if (!e.program)
 241                         goto out;
 242         }
 243         if (domainname && strcmp(domainname, "any")) {
 244                 if (!tomoyo_correct_domain(domainname)) {
 245                         if (!tomoyo_correct_path(domainname))
 246                                 goto out;
 247                         e.is_last_name = true;
 248                 }
 249                 e.domainname = tomoyo_get_name(domainname);
 250                 if (!e.domainname)
 251                         goto out;
 252         }
 253         param->list = &param->ns->policy_list[TOMOYO_ID_TRANSITION_CONTROL];
 254         error = tomoyo_update_policy(&e.head, sizeof(e), param,
 255                                      tomoyo_same_transition_control);
 256 out:
 257         tomoyo_put_name(e.domainname);
 258         tomoyo_put_name(e.program);
 259         return error;
 260 }
 261
 262 /**
 263  * tomoyo_scan_transition - Try to find specific domain transition type.
 264  *
 265  * @list:       Pointer to "struct list_head".
 266  * @domainname: The name of current domain.
 267  * @program:    The name of requested program.
 268  * @last_name:  The last component of @domainname.
 269  * @type:       One of values in "enum tomoyo_transition_type".
 270  *
 271  * Returns true if found one, false otherwise.
 272  *
 273  * Caller holds tomoyo_read_lock().
 274  */
 275 static inline bool tomoyo_scan_transition
 276 (const struct list_head *list, const struct tomoyo_path_info *domainname,
 277  const struct tomoyo_path_info *program, const char *last_name,
 278  const enum tomoyo_transition_type type)
 279 {
 280         const struct tomoyo_transition_control *ptr;
 281         list_for_each_entry_rcu(ptr, list, head.list) {
 282                 if (ptr->head.is_deleted || ptr->type != type)
 283                         continue;
 284                 if (ptr->domainname) {
 285                         if (!ptr->is_last_name) {
 286                                 if (ptr->domainname != domainname)
 287                                         continue;
 288                         } else {
 289                                 /*
 290                                  * Use direct strcmp() since this is
 291                                  * unlikely used.
 292                                  */
 293                                 if (strcmp(ptr->domainname->name, last_name))
 294                                         continue;
 295                         }
 296                 }
 297                 if (ptr->program && tomoyo_pathcmp(ptr->program, program))
 298                         continue;
 299                 return true;
 300         }
 301         return false;
 302 }
 303
 304 /**
 305  * tomoyo_transition_type - Get domain transition type.
 306  *
 307  * @ns:         Pointer to "struct tomoyo_policy_namespace".
 308  * @domainname: The name of current domain.
 309  * @program:    The name of requested program.
 310  *
 311  * Returns TOMOYO_TRANSITION_CONTROL_TRANSIT if executing @program causes
 312  * domain transition across namespaces, TOMOYO_TRANSITION_CONTROL_INITIALIZE if
 313  * executing @program reinitializes domain transition within that namespace,
 314  * TOMOYO_TRANSITION_CONTROL_KEEP if executing @program stays at @domainname ,
 315  * others otherwise.
 316  *
 317  * Caller holds tomoyo_read_lock().
 318  */
 319 static enum tomoyo_transition_type tomoyo_transition_type
 320 (const struct tomoyo_policy_namespace *ns,
 321  const struct tomoyo_path_info *domainname,
 322  const struct tomoyo_path_info *program)
 323 {
 324         const char *last_name = tomoyo_last_word(domainname->name);
 325         enum tomoyo_transition_type type = TOMOYO_TRANSITION_CONTROL_NO_RESET;
 326         while (type < TOMOYO_MAX_TRANSITION_TYPE) {
 327                 const struct list_head * const list =
 328                         &ns->policy_list[TOMOYO_ID_TRANSITION_CONTROL];
 329                 if (!tomoyo_scan_transition(list, domainname, program,
 330                                             last_name, type)) {
 331                         type++;
 332                         continue;
 333                 }
 334                 if (type != TOMOYO_TRANSITION_CONTROL_NO_RESET &&
 335                     type != TOMOYO_TRANSITION_CONTROL_NO_INITIALIZE)
 336                         break;
 337                 /*
 338                  * Do not check for reset_domain if no_reset_domain matched.
 339                  * Do not check for initialize_domain if no_initialize_domain
 340                  * matched.
 341                  */
 342                 type++;
 343                 type++;
 344         }
 345         return type;
 346 }
 347
 348 /**
 349  * tomoyo_same_aggregator - Check for duplicated "struct tomoyo_aggregator" entry.
 350  *
 351  * @a: Pointer to "struct tomoyo_acl_head".
 352  * @b: Pointer to "struct tomoyo_acl_head".
 353  *
 354  * Returns true if @a == @b, false otherwise.
 355  */
 356 static bool tomoyo_same_aggregator(const struct tomoyo_acl_head *a,
 357                                    const struct tomoyo_acl_head *b)
 358 {
 359         const struct tomoyo_aggregator *p1 = container_of(a, typeof(*p1),
 360                                                           head);
 361         const struct tomoyo_aggregator *p2 = container_of(b, typeof(*p2),
 362                                                           head);
 363         return p1->original_name == p2->original_name &&
 364                 p1->aggregated_name == p2->aggregated_name;
 365 }
 366
 367 /**
 368  * tomoyo_write_aggregator - Write "struct tomoyo_aggregator" list.
 369  *
 370  * @param: Pointer to "struct tomoyo_acl_param".
 371  *
 372  * Returns 0 on success, negative value otherwise.
 373  *
 374  * Caller holds tomoyo_read_lock().
 375  */
 376 int tomoyo_write_aggregator(struct tomoyo_acl_param *param)
 377 {
 378         struct tomoyo_aggregator e = { };
 379         int error = param->is_delete ? -ENOENT : -ENOMEM;
 380         const char *original_name = tomoyo_read_token(param);
 381         const char *aggregated_name = tomoyo_read_token(param);
 382         if (!tomoyo_correct_word(original_name) ||
 383             !tomoyo_correct_path(aggregated_name))
 384                 return -EINVAL;
 385         e.original_name = tomoyo_get_name(original_name);
 386         e.aggregated_name = tomoyo_get_name(aggregated_name);
 387         if (!e.original_name || !e.aggregated_name ||
 388             e.aggregated_name->is_patterned) /* No patterns allowed. */
 389                 goto out;
 390         param->list = &param->ns->policy_list[TOMOYO_ID_AGGREGATOR];
 391         error = tomoyo_update_policy(&e.head, sizeof(e), param,
 392                                      tomoyo_same_aggregator);
 393 out:
 394         tomoyo_put_name(e.original_name);
 395         tomoyo_put_name(e.aggregated_name);
 396         return error;
 397 }
 398
 399 /**
 400  * tomoyo_find_namespace - Find specified namespace.
 401  *
 402  * @name: Name of namespace to find.
 403  * @len:  Length of @name.
 404  *
 405  * Returns pointer to "struct tomoyo_policy_namespace" if found,
 406  * NULL otherwise.
 407  *
 408  * Caller holds tomoyo_read_lock().
 409  */
 410 static struct tomoyo_policy_namespace *tomoyo_find_namespace
 411 (const char *name, const unsigned int len)
 412 {
 413         struct tomoyo_policy_namespace *ns;
 414         list_for_each_entry(ns, &tomoyo_namespace_list, namespace_list) {
 415                 if (strncmp(name, ns->name, len) ||
 416                     (name[len] && name[len] != ' '))
 417                         continue;
 418                 return ns;
 419         }
 420         return NULL;
 421 }
 422
 423 /**
 424  * tomoyo_assign_namespace - Create a new namespace.
 425  *
 426  * @domainname: Name of namespace to create.
 427  *
 428  * Returns pointer to "struct tomoyo_policy_namespace" on success,
 429  * NULL otherwise.
 430  *
 431  * Caller holds tomoyo_read_lock().
 432  */
 433 struct tomoyo_policy_namespace *tomoyo_assign_namespace(const char *domainname)
 434 {
 435         struct tomoyo_policy_namespace *ptr;
 436         struct tomoyo_policy_namespace *entry;
 437         const char *cp = domainname;
 438         unsigned int len = 0;
 439         while (*cp && *cp++ != ' ')
 440                 len++;
 441         ptr = tomoyo_find_namespace(domainname, len);
 442         if (ptr)
 443                 return ptr;
 444         if (len >= TOMOYO_EXEC_TMPSIZE - 10 || !tomoyo_domain_def(domainname))
 445                 return NULL;
 446         entry = kzalloc(sizeof(*entry) + len + 1, GFP_NOFS);
 447         if (!entry)
 448                 return NULL;
 449         if (mutex_lock_interruptible(&tomoyo_policy_lock))
 450                 goto out;
 451         ptr = tomoyo_find_namespace(domainname, len);
 452         if (!ptr && tomoyo_memory_ok(entry)) {
 453                 char *name = (char *) (entry + 1);
 454                 ptr = entry;
 455                 memmove(name, domainname, len);
 456                 name[len] = '\0';
 457                 entry->name = name;
 458                 tomoyo_init_policy_namespace(entry);
 459                 entry = NULL;
 460         }
 461         mutex_unlock(&tomoyo_policy_lock);
 462 out:
 463         kfree(entry);
 464         return ptr;
 465 }
 466
 467 /**
 468  * tomoyo_namespace_jump - Check for namespace jump.
 469  *
 470  * @domainname: Name of domain.
 471  *
 472  * Returns true if namespace differs, false otherwise.
 473  */
 474 static bool tomoyo_namespace_jump(const char *domainname)
 475 {
 476         const char *namespace = tomoyo_current_namespace()->name;
 477         const int len = strlen(namespace);
 478         return strncmp(domainname, namespace, len) ||
 479                 (domainname[len] && domainname[len] != ' ');
 480 }
 481
 482 /**
 483  * tomoyo_assign_domain - Create a domain or a namespace.
 484  *
 485  * @domainname: The name of domain.
 486  * @transit:    True if transit to domain found or created.
 487  *
 488  * Returns pointer to "struct tomoyo_domain_info" on success, NULL otherwise.
 489  *
 490  * Caller holds tomoyo_read_lock().
 491  */
 492 struct tomoyo_domain_info *tomoyo_assign_domain(const char *domainname,
 493                                                 const bool transit)
 494 {
 495         struct tomoyo_domain_info e = { };
 496         struct tomoyo_domain_info *entry = tomoyo_find_domain(domainname);
 497         bool created = false;
 498         if (entry) {
 499                 if (transit) {
 500                         /*
 501                          * Since namespace is created at runtime, profiles may
 502                          * not be created by the moment the process transits to
 503                          * that domain. Do not perform domain transition if
 504                          * profile for that domain is not yet created.
 505                          */
 506                         if (!entry->ns->profile_ptr[entry->profile])
 507                                 return NULL;
 508                 }
 509                 return entry;
 510         }
 511         /* Requested domain does not exist. */
 512         /* Don't create requested domain if domainname is invalid. */
 513         if (strlen(domainname) >= TOMOYO_EXEC_TMPSIZE - 10 ||
 514             !tomoyo_correct_domain(domainname))
 515                 return NULL;
 516         /*
 517          * Since definition of profiles and acl_groups may differ across
 518          * namespaces, do not inherit "use_profile" and "use_group" settings
 519          * by automatically creating requested domain upon domain transition.
 520          */
 521         if (transit && tomoyo_namespace_jump(domainname))
 522                 return NULL;
 523         e.ns = tomoyo_assign_namespace(domainname);
 524         if (!e.ns)
 525                 return NULL;
 526         /*
 527          * "use_profile" and "use_group" settings for automatically created
 528          * domains are inherited from current domain. These are 0 for manually
 529          * created domains.
 530          */
 531         if (transit) {
 532                 const struct tomoyo_domain_info *domain = tomoyo_domain();
 533                 e.profile = domain->profile;
 534                 e.group = domain->group;
 535         }
 536         e.domainname = tomoyo_get_name(domainname);
 537         if (!e.domainname)
 538                 return NULL;
 539         if (mutex_lock_interruptible(&tomoyo_policy_lock))
 540                 goto out;
 541         entry = tomoyo_find_domain(domainname);
 542         if (!entry) {
 543                 entry = tomoyo_commit_ok(&e, sizeof(e));
 544                 if (entry) {
 545                         INIT_LIST_HEAD(&entry->acl_info_list);
 546                         list_add_tail_rcu(&entry->list, &tomoyo_domain_list);
 547                         created = true;
 548                 }
 549         }
 550         mutex_unlock(&tomoyo_policy_lock);
 551 out:
 552         tomoyo_put_name(e.domainname);
 553         if (entry && transit) {
 554                 if (created) {
 555                         struct tomoyo_request_info r;
 556                         tomoyo_init_request_info(&r, entry,
 557                                                  TOMOYO_MAC_FILE_EXECUTE);
 558                         r.granted = false;
 559                         tomoyo_write_log(&r, "use_profile %u\n",
 560                                          entry->profile);
 561                         tomoyo_write_log(&r, "use_group %u\n", entry->group);
 562                 }
 563         }
 564         return entry;
 565 }
 566
 567 /**
 568  * tomoyo_find_next_domain - Find a domain.
 569  *
 570  * @bprm: Pointer to "struct linux_binprm".
 571  *
 572  * Returns 0 on success, negative value otherwise.
 573  *
 574  * Caller holds tomoyo_read_lock().
 575  */
 576 int tomoyo_find_next_domain(struct linux_binprm *bprm)
 577 {
 578         struct tomoyo_request_info r;
 579         char *tmp = kzalloc(TOMOYO_EXEC_TMPSIZE, GFP_NOFS);
 580         struct tomoyo_domain_info *old_domain = tomoyo_domain();
 581         struct tomoyo_domain_info *domain = NULL;
 582         const char *original_name = bprm->filename;
 583         u8 mode;
 584         bool is_enforce;
 585         int retval = -ENOMEM;
 586         bool need_kfree = false;
 587         bool reject_on_transition_failure = false;
 588         struct tomoyo_path_info rn = { }; /* real name */
 589
 590         mode = tomoyo_init_request_info(&r, NULL, TOMOYO_MAC_FILE_EXECUTE);
 591         is_enforce = (mode == TOMOYO_CONFIG_ENFORCING);
 592         if (!tmp)
 593                 goto out;
 594
 595  retry:
 596         if (need_kfree) {
 597                 kfree(rn.name);
 598                 need_kfree = false;
 599         }
 600         /* Get symlink's pathname of program. */
 601         retval = -ENOENT;
 602         rn.name = tomoyo_realpath_nofollow(original_name);
 603         if (!rn.name)
 604                 goto out;
 605         tomoyo_fill_path_info(&rn);
 606         need_kfree = true;
 607
 608         /* Check 'aggregator' directive. */
 609         {
 610                 struct tomoyo_aggregator *ptr;
 611                 struct list_head *list =
 612                         &old_domain->ns->policy_list[TOMOYO_ID_AGGREGATOR];
 613                 /* Check 'aggregator' directive. */
 614                 list_for_each_entry_rcu(ptr, list, head.list) {
 615                         if (ptr->head.is_deleted ||
 616                             !tomoyo_path_matches_pattern(&rn,
 617                                                          ptr->original_name))
 618                                 continue;
 619                         kfree(rn.name);
 620                         need_kfree = false;
 621                         /* This is OK because it is read only. */
 622                         rn = *ptr->aggregated_name;
 623                         break;
 624                 }
 625         }
 626
 627         /* Check execute permission. */
 628         retval = tomoyo_path_permission(&r, TOMOYO_TYPE_EXECUTE, &rn);
 629         if (retval == TOMOYO_RETRY_REQUEST)
 630                 goto retry;
 631         if (retval < 0)
 632                 goto out;
 633         /*
 634          * To be able to specify domainnames with wildcards, use the
 635          * pathname specified in the policy (which may contain
 636          * wildcard) rather than the pathname passed to execve()
 637          * (which never contains wildcard).
 638          */
 639         if (r.param.path.matched_path) {
 640                 if (need_kfree)
 641                         kfree(rn.name);
 642                 need_kfree = false;
 643                 /* This is OK because it is read only. */
 644                 rn = *r.param.path.matched_path;
 645         }
 646
 647         /* Calculate domain to transit to. */
 648         switch (tomoyo_transition_type(old_domain->ns, old_domain->domainname,
 649                                        &rn)) {
 650         case TOMOYO_TRANSITION_CONTROL_RESET:
 651                 /* Transit to the root of specified namespace. */
 652                 snprintf(tmp, TOMOYO_EXEC_TMPSIZE - 1, "<%s>", rn.name);
 653                 /*
 654                  * Make do_execve() fail if domain transition across namespaces
 655                  * has failed.
 656                  */
 657                 reject_on_transition_failure = true;
 658                 break;
 659         case TOMOYO_TRANSITION_CONTROL_INITIALIZE:
 660                 /* Transit to the child of current namespace's root. */
 661                 snprintf(tmp, TOMOYO_EXEC_TMPSIZE - 1, "%s %s",
 662                          old_domain->ns->name, rn.name);
 663                 break;
 664         case TOMOYO_TRANSITION_CONTROL_KEEP:
 665                 /* Keep current domain. */
 666                 domain = old_domain;
 667                 break;
 668         default:
 669                 if (old_domain == &tomoyo_kernel_domain &&
 670                     !tomoyo_policy_loaded) {
 671                         /*
 672                          * Needn't to transit from kernel domain before
 673                          * starting /sbin/init. But transit from kernel domain
 674                          * if executing initializers because they might start
 675                          * before /sbin/init.
 676                          */
 677                         domain = old_domain;
 678                 } else {
 679                         /* Normal domain transition. */
 680                         snprintf(tmp, TOMOYO_EXEC_TMPSIZE - 1, "%s %s",
 681                                  old_domain->domainname->name, rn.name);
 682                 }
 683                 break;
 684         }
 685         if (!domain)
 686                 domain = tomoyo_assign_domain(tmp, true);
 687         if (domain)
 688                 retval = 0;
 689         else if (reject_on_transition_failure) {
 690                 printk(KERN_WARNING "ERROR: Domain '%s' not ready.\n", tmp);
 691                 retval = -ENOMEM;
 692         } else if (r.mode == TOMOYO_CONFIG_ENFORCING)
 693                 retval = -ENOMEM;
 694         else {
 695                 retval = 0;
 696                 if (!old_domain->flags[TOMOYO_DIF_TRANSITION_FAILED]) {
 697                         old_domain->flags[TOMOYO_DIF_TRANSITION_FAILED] = true;
 698                         r.granted = false;
 699                         tomoyo_write_log(&r, "%s", tomoyo_dif
 700                                          [TOMOYO_DIF_TRANSITION_FAILED]);
 701                         printk(KERN_WARNING
 702                                "ERROR: Domain '%s' not defined.\n", tmp);
 703                 }
 704         }
 705  out:
 706         if (!domain)
 707                 domain = old_domain;
 708         /* Update reference count on "struct tomoyo_domain_info". */
 709         atomic_inc(&domain->users);
 710         bprm->cred->security = domain;
 711         if (need_kfree)
 712                 kfree(rn.name);
 713         kfree(tmp);
 714         return retval;
 715 }
 716
 717 /**
 718  * tomoyo_dump_page - Dump a page to buffer.
 719  *
 720  * @bprm: Pointer to "struct linux_binprm".
 721  * @pos:  Location to dump.
 722  * @dump: Poiner to "struct tomoyo_page_dump".
 723  *
 724  * Returns true on success, false otherwise.
 725  */
 726 bool tomoyo_dump_page(struct linux_binprm *bprm, unsigned long pos,
 727                       struct tomoyo_page_dump *dump)
 728 {
 729         struct page *page;
 730         /* dump->data is released by tomoyo_finish_execve(). */
 731         if (!dump->data) {
 732                 dump->data = kzalloc(PAGE_SIZE, GFP_NOFS);
 733                 if (!dump->data)
 734                         return false;
 735         }
 736         /* Same with get_arg_page(bprm, pos, 0) in fs/exec.c */
 737 #ifdef CONFIG_MMU
 738         if (get_user_pages(current, bprm->mm, pos, 1, 0, 1, &page, NULL) <= 0)
 739                 return false;
 740 #else
 741         page = bprm->page[pos / PAGE_SIZE];
 742 #endif
 743         if (page != dump->page) {
 744                 const unsigned int offset = pos % PAGE_SIZE;
 745                 /*
 746                  * Maybe kmap()/kunmap() should be used here.
 747                  * But remove_arg_zero() uses kmap_atomic()/kunmap_atomic().
 748                  * So do I.
 749                  */
 750                 char *kaddr = kmap_atomic(page, KM_USER0);
 751                 dump->page = page;
 752                 memcpy(dump->data + offset, kaddr + offset,
 753                        PAGE_SIZE - offset);
 754                 kunmap_atomic(kaddr, KM_USER0);
 755         }
 756         /* Same with put_arg_page(page) in fs/exec.c */
 757 #ifdef CONFIG_MMU
 758         put_page(page);
 759 #endif
 760         return true;
 761 }