security/tomoyo/domain.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * security/tomoyo/domain.c
   4  *
   5  * Copyright (C) 2005-2011  NTT DATA CORPORATION
   6  */
   7
   8 #include "common.h"
   9
  10 #include <linux/binfmts.h>
  11 #include <linux/slab.h>
  12 #include <linux/rculist.h>
  13
  14 /* Variables definitions.*/
  15
  16 /* The initial domain. */
  17 struct tomoyo_domain_info tomoyo_kernel_domain;
  18
  19 /**
  20  * tomoyo_update_policy - Update an entry for exception policy.
  21  *
  22  * @new_entry:       Pointer to "struct tomoyo_acl_info".
  23  * @size:            Size of @new_entry in bytes.
  24  * @param:           Pointer to "struct tomoyo_acl_param".
  25  * @check_duplicate: Callback function to find duplicated entry.
  26  *
  27  * Returns 0 on success, negative value otherwise.
  28  *
  29  * Caller holds tomoyo_read_lock().
  30  */
  31 int tomoyo_update_policy(struct tomoyo_acl_head *new_entry, const int size,
  32                          struct tomoyo_acl_param *param,
  33                          bool (*check_duplicate) (const struct tomoyo_acl_head
  34                                                   *,
  35                                                   const struct tomoyo_acl_head
  36                                                   *))
  37 {
  38         int error = param->is_delete ? -ENOENT : -ENOMEM;
  39         struct tomoyo_acl_head *entry;
  40         struct list_head *list = param->list;
  41
  42         if (mutex_lock_interruptible(&tomoyo_policy_lock))
  43                 return -ENOMEM;
  44         list_for_each_entry_rcu(entry, list, list) {
  45                 if (entry->is_deleted == TOMOYO_GC_IN_PROGRESS)
  46                         continue;
  47                 if (!check_duplicate(entry, new_entry))
  48                         continue;
  49                 entry->is_deleted = param->is_delete;
  50                 error = 0;
  51                 break;
  52         }
  53         if (error && !param->is_delete) {
  54                 entry = tomoyo_commit_ok(new_entry, size);
  55                 if (entry) {
  56                         list_add_tail_rcu(&entry->list, list);
  57                         error = 0;
  58                 }
  59         }
  60         mutex_unlock(&tomoyo_policy_lock);
  61         return error;
  62 }
  63
  64 /**
  65  * tomoyo_same_acl_head - Check for duplicated "struct tomoyo_acl_info" entry.
  66  *
  67  * @a: Pointer to "struct tomoyo_acl_info".
  68  * @b: Pointer to "struct tomoyo_acl_info".
  69  *
  70  * Returns true if @a == @b, false otherwise.
  71  */
  72 static inline bool tomoyo_same_acl_head(const struct tomoyo_acl_info *a,
  73                                         const struct tomoyo_acl_info *b)
  74 {
  75         return a->type == b->type && a->cond == b->cond;
  76 }
  77
  78 /**
  79  * tomoyo_update_domain - Update an entry for domain policy.
  80  *
  81  * @new_entry:       Pointer to "struct tomoyo_acl_info".
  82  * @size:            Size of @new_entry in bytes.
  83  * @param:           Pointer to "struct tomoyo_acl_param".
  84  * @check_duplicate: Callback function to find duplicated entry.
  85  * @merge_duplicate: Callback function to merge duplicated entry.
  86  *
  87  * Returns 0 on success, negative value otherwise.
  88  *
  89  * Caller holds tomoyo_read_lock().
  90  */
  91 int tomoyo_update_domain(struct tomoyo_acl_info *new_entry, const int size,
  92                          struct tomoyo_acl_param *param,
  93                          bool (*check_duplicate) (const struct tomoyo_acl_info
  94                                                   *,
  95                                                   const struct tomoyo_acl_info
  96                                                   *),
  97                          bool (*merge_duplicate) (struct tomoyo_acl_info *,
  98                                                   struct tomoyo_acl_info *,
  99                                                   const bool))
 100 {
 101         const bool is_delete = param->is_delete;
 102         int error = is_delete ? -ENOENT : -ENOMEM;
 103         struct tomoyo_acl_info *entry;
 104         struct list_head * const list = param->list;
 105
 106         if (param->data[0]) {
 107                 new_entry->cond = tomoyo_get_condition(param);
 108                 if (!new_entry->cond)
 109                         return -EINVAL;
 110                 /*
 111                  * Domain transition preference is allowed for only
 112                  * "file execute" entries.
 113                  */
 114                 if (new_entry->cond->transit &&
 115                     !(new_entry->type == TOMOYO_TYPE_PATH_ACL &&
 116                       container_of(new_entry, struct tomoyo_path_acl, head)
 117                       ->perm == 1 << TOMOYO_TYPE_EXECUTE))
 118                         goto out;
 119         }
 120         if (mutex_lock_interruptible(&tomoyo_policy_lock))
 121                 goto out;
 122         list_for_each_entry_rcu(entry, list, list) {
 123                 if (entry->is_deleted == TOMOYO_GC_IN_PROGRESS)
 124                         continue;
 125                 if (!tomoyo_same_acl_head(entry, new_entry) ||
 126                     !check_duplicate(entry, new_entry))
 127                         continue;
 128                 if (merge_duplicate)
 129                         entry->is_deleted = merge_duplicate(entry, new_entry,
 130                                                             is_delete);
 131                 else
 132                         entry->is_deleted = is_delete;
 133                 error = 0;
 134                 break;
 135         }
 136         if (error && !is_delete) {
 137                 entry = tomoyo_commit_ok(new_entry, size);
 138                 if (entry) {
 139                         list_add_tail_rcu(&entry->list, list);
 140                         error = 0;
 141                 }
 142         }
 143         mutex_unlock(&tomoyo_policy_lock);
 144 out:
 145         tomoyo_put_condition(new_entry->cond);
 146         return error;
 147 }
 148
 149 /**
 150  * tomoyo_check_acl - Do permission check.
 151  *
 152  * @r:           Pointer to "struct tomoyo_request_info".
 153  * @check_entry: Callback function to check type specific parameters.
 154  *
 155  * Returns 0 on success, negative value otherwise.
 156  *
 157  * Caller holds tomoyo_read_lock().
 158  */
 159 void tomoyo_check_acl(struct tomoyo_request_info *r,
 160                       bool (*check_entry) (struct tomoyo_request_info *,
 161                                            const struct tomoyo_acl_info *))
 162 {
 163         const struct tomoyo_domain_info *domain = r->domain;
 164         struct tomoyo_acl_info *ptr;
 165         bool retried = false;
 166         const struct list_head *list = &domain->acl_info_list;
 167
 168 retry:
 169         list_for_each_entry_rcu(ptr, list, list) {
 170                 if (ptr->is_deleted || ptr->type != r->param_type)
 171                         continue;
 172                 if (!check_entry(r, ptr))
 173                         continue;
 174                 if (!tomoyo_condition(r, ptr->cond))
 175                         continue;
 176                 r->matched_acl = ptr;
 177                 r->granted = true;
 178                 return;
 179         }
 180         if (!retried) {
 181                 retried = true;
 182                 list = &domain->ns->acl_group[domain->group];
 183                 goto retry;
 184         }
 185         r->granted = false;
 186 }
 187
 188 /* The list for "struct tomoyo_domain_info". */
 189 LIST_HEAD(tomoyo_domain_list);
 190
 191 /**
 192  * tomoyo_last_word - Get last component of a domainname.
 193  *
 194  * @name: Domainname to check.
 195  *
 196  * Returns the last word of @domainname.
 197  */
 198 static const char *tomoyo_last_word(const char *name)
 199 {
 200         const char *cp = strrchr(name, ' ');
 201         if (cp)
 202                 return cp + 1;
 203         return name;
 204 }
 205
 206 /**
 207  * tomoyo_same_transition_control - Check for duplicated "struct tomoyo_transition_control" entry.
 208  *
 209  * @a: Pointer to "struct tomoyo_acl_head".
 210  * @b: Pointer to "struct tomoyo_acl_head".
 211  *
 212  * Returns true if @a == @b, false otherwise.
 213  */
 214 static bool tomoyo_same_transition_control(const struct tomoyo_acl_head *a,
 215                                            const struct tomoyo_acl_head *b)
 216 {
 217         const struct tomoyo_transition_control *p1 = container_of(a,
 218                                                                   typeof(*p1),
 219                                                                   head);
 220         const struct tomoyo_transition_control *p2 = container_of(b,
 221                                                                   typeof(*p2),
 222                                                                   head);
 223         return p1->type == p2->type && p1->is_last_name == p2->is_last_name
 224                 && p1->domainname == p2->domainname
 225                 && p1->program == p2->program;
 226 }
 227
 228 /**
 229  * tomoyo_write_transition_control - Write "struct tomoyo_transition_control" list.
 230  *
 231  * @param: Pointer to "struct tomoyo_acl_param".
 232  * @type:  Type of this entry.
 233  *
 234  * Returns 0 on success, negative value otherwise.
 235  */
 236 int tomoyo_write_transition_control(struct tomoyo_acl_param *param,
 237                                     const u8 type)
 238 {
 239         struct tomoyo_transition_control e = { .type = type };
 240         int error = param->is_delete ? -ENOENT : -ENOMEM;
 241         char *program = param->data;
 242         char *domainname = strstr(program, " from ");
 243         if (domainname) {
 244                 *domainname = '\0';
 245                 domainname += 6;
 246         } else if (type == TOMOYO_TRANSITION_CONTROL_NO_KEEP ||
 247                    type == TOMOYO_TRANSITION_CONTROL_KEEP) {
 248                 domainname = program;
 249                 program = NULL;
 250         }
 251         if (program && strcmp(program, "any")) {
 252                 if (!tomoyo_correct_path(program))
 253                         return -EINVAL;
 254                 e.program = tomoyo_get_name(program);
 255                 if (!e.program)
 256                         goto out;
 257         }
 258         if (domainname && strcmp(domainname, "any")) {
 259                 if (!tomoyo_correct_domain(domainname)) {
 260                         if (!tomoyo_correct_path(domainname))
 261                                 goto out;
 262                         e.is_last_name = true;
 263                 }
 264                 e.domainname = tomoyo_get_name(domainname);
 265                 if (!e.domainname)
 266                         goto out;
 267         }
 268         param->list = &param->ns->policy_list[TOMOYO_ID_TRANSITION_CONTROL];
 269         error = tomoyo_update_policy(&e.head, sizeof(e), param,
 270                                      tomoyo_same_transition_control);
 271 out:
 272         tomoyo_put_name(e.domainname);
 273         tomoyo_put_name(e.program);
 274         return error;
 275 }
 276
 277 /**
 278  * tomoyo_scan_transition - Try to find specific domain transition type.
 279  *
 280  * @list:       Pointer to "struct list_head".
 281  * @domainname: The name of current domain.
 282  * @program:    The name of requested program.
 283  * @last_name:  The last component of @domainname.
 284  * @type:       One of values in "enum tomoyo_transition_type".
 285  *
 286  * Returns true if found one, false otherwise.
 287  *
 288  * Caller holds tomoyo_read_lock().
 289  */
 290 static inline bool tomoyo_scan_transition
 291 (const struct list_head *list, const struct tomoyo_path_info *domainname,
 292  const struct tomoyo_path_info *program, const char *last_name,
 293  const enum tomoyo_transition_type type)
 294 {
 295         const struct tomoyo_transition_control *ptr;
 296         list_for_each_entry_rcu(ptr, list, head.list) {
 297                 if (ptr->head.is_deleted || ptr->type != type)
 298                         continue;
 299                 if (ptr->domainname) {
 300                         if (!ptr->is_last_name) {
 301                                 if (ptr->domainname != domainname)
 302                                         continue;
 303                         } else {
 304                                 /*
 305                                  * Use direct strcmp() since this is
 306                                  * unlikely used.
 307                                  */
 308                                 if (strcmp(ptr->domainname->name, last_name))
 309                                         continue;
 310                         }
 311                 }
 312                 if (ptr->program && tomoyo_pathcmp(ptr->program, program))
 313                         continue;
 314                 return true;
 315         }
 316         return false;
 317 }
 318
 319 /**
 320  * tomoyo_transition_type - Get domain transition type.
 321  *
 322  * @ns:         Pointer to "struct tomoyo_policy_namespace".
 323  * @domainname: The name of current domain.
 324  * @program:    The name of requested program.
 325  *
 326  * Returns TOMOYO_TRANSITION_CONTROL_TRANSIT if executing @program causes
 327  * domain transition across namespaces, TOMOYO_TRANSITION_CONTROL_INITIALIZE if
 328  * executing @program reinitializes domain transition within that namespace,
 329  * TOMOYO_TRANSITION_CONTROL_KEEP if executing @program stays at @domainname ,
 330  * others otherwise.
 331  *
 332  * Caller holds tomoyo_read_lock().
 333  */
 334 static enum tomoyo_transition_type tomoyo_transition_type
 335 (const struct tomoyo_policy_namespace *ns,
 336  const struct tomoyo_path_info *domainname,
 337  const struct tomoyo_path_info *program)
 338 {
 339         const char *last_name = tomoyo_last_word(domainname->name);
 340         enum tomoyo_transition_type type = TOMOYO_TRANSITION_CONTROL_NO_RESET;
 341         while (type < TOMOYO_MAX_TRANSITION_TYPE) {
 342                 const struct list_head * const list =
 343                         &ns->policy_list[TOMOYO_ID_TRANSITION_CONTROL];
 344                 if (!tomoyo_scan_transition(list, domainname, program,
 345                                             last_name, type)) {
 346                         type++;
 347                         continue;
 348                 }
 349                 if (type != TOMOYO_TRANSITION_CONTROL_NO_RESET &&
 350                     type != TOMOYO_TRANSITION_CONTROL_NO_INITIALIZE)
 351                         break;
 352                 /*
 353                  * Do not check for reset_domain if no_reset_domain matched.
 354                  * Do not check for initialize_domain if no_initialize_domain
 355                  * matched.
 356                  */
 357                 type++;
 358                 type++;
 359         }
 360         return type;
 361 }
 362
 363 /**
 364  * tomoyo_same_aggregator - Check for duplicated "struct tomoyo_aggregator" entry.
 365  *
 366  * @a: Pointer to "struct tomoyo_acl_head".
 367  * @b: Pointer to "struct tomoyo_acl_head".
 368  *
 369  * Returns true if @a == @b, false otherwise.
 370  */
 371 static bool tomoyo_same_aggregator(const struct tomoyo_acl_head *a,
 372                                    const struct tomoyo_acl_head *b)
 373 {
 374         const struct tomoyo_aggregator *p1 = container_of(a, typeof(*p1),
 375                                                           head);
 376         const struct tomoyo_aggregator *p2 = container_of(b, typeof(*p2),
 377                                                           head);
 378         return p1->original_name == p2->original_name &&
 379                 p1->aggregated_name == p2->aggregated_name;
 380 }
 381
 382 /**
 383  * tomoyo_write_aggregator - Write "struct tomoyo_aggregator" list.
 384  *
 385  * @param: Pointer to "struct tomoyo_acl_param".
 386  *
 387  * Returns 0 on success, negative value otherwise.
 388  *
 389  * Caller holds tomoyo_read_lock().
 390  */
 391 int tomoyo_write_aggregator(struct tomoyo_acl_param *param)
 392 {
 393         struct tomoyo_aggregator e = { };
 394         int error = param->is_delete ? -ENOENT : -ENOMEM;
 395         const char *original_name = tomoyo_read_token(param);
 396         const char *aggregated_name = tomoyo_read_token(param);
 397         if (!tomoyo_correct_word(original_name) ||
 398             !tomoyo_correct_path(aggregated_name))
 399                 return -EINVAL;
 400         e.original_name = tomoyo_get_name(original_name);
 401         e.aggregated_name = tomoyo_get_name(aggregated_name);
 402         if (!e.original_name || !e.aggregated_name ||
 403             e.aggregated_name->is_patterned) /* No patterns allowed. */
 404                 goto out;
 405         param->list = &param->ns->policy_list[TOMOYO_ID_AGGREGATOR];
 406         error = tomoyo_update_policy(&e.head, sizeof(e), param,
 407                                      tomoyo_same_aggregator);
 408 out:
 409         tomoyo_put_name(e.original_name);
 410         tomoyo_put_name(e.aggregated_name);
 411         return error;
 412 }
 413
 414 /**
 415  * tomoyo_find_namespace - Find specified namespace.
 416  *
 417  * @name: Name of namespace to find.
 418  * @len:  Length of @name.
 419  *
 420  * Returns pointer to "struct tomoyo_policy_namespace" if found,
 421  * NULL otherwise.
 422  *
 423  * Caller holds tomoyo_read_lock().
 424  */
 425 static struct tomoyo_policy_namespace *tomoyo_find_namespace
 426 (const char *name, const unsigned int len)
 427 {
 428         struct tomoyo_policy_namespace *ns;
 429         list_for_each_entry(ns, &tomoyo_namespace_list, namespace_list) {
 430                 if (strncmp(name, ns->name, len) ||
 431                     (name[len] && name[len] != ' '))
 432                         continue;
 433                 return ns;
 434         }
 435         return NULL;
 436 }
 437
 438 /**
 439  * tomoyo_assign_namespace - Create a new namespace.
 440  *
 441  * @domainname: Name of namespace to create.
 442  *
 443  * Returns pointer to "struct tomoyo_policy_namespace" on success,
 444  * NULL otherwise.
 445  *
 446  * Caller holds tomoyo_read_lock().
 447  */
 448 struct tomoyo_policy_namespace *tomoyo_assign_namespace(const char *domainname)
 449 {
 450         struct tomoyo_policy_namespace *ptr;
 451         struct tomoyo_policy_namespace *entry;
 452         const char *cp = domainname;
 453         unsigned int len = 0;
 454         while (*cp && *cp++ != ' ')
 455                 len++;
 456         ptr = tomoyo_find_namespace(domainname, len);
 457         if (ptr)
 458                 return ptr;
 459         if (len >= TOMOYO_EXEC_TMPSIZE - 10 || !tomoyo_domain_def(domainname))
 460                 return NULL;
 461         entry = kzalloc(sizeof(*entry) + len + 1, GFP_NOFS);
 462         if (!entry)
 463                 return NULL;
 464         if (mutex_lock_interruptible(&tomoyo_policy_lock))
 465                 goto out;
 466         ptr = tomoyo_find_namespace(domainname, len);
 467         if (!ptr && tomoyo_memory_ok(entry)) {
 468                 char *name = (char *) (entry + 1);
 469                 ptr = entry;
 470                 memmove(name, domainname, len);
 471                 name[len] = '\0';
 472                 entry->name = name;
 473                 tomoyo_init_policy_namespace(entry);
 474                 entry = NULL;
 475         }
 476         mutex_unlock(&tomoyo_policy_lock);
 477 out:
 478         kfree(entry);
 479         return ptr;
 480 }
 481
 482 /**
 483  * tomoyo_namespace_jump - Check for namespace jump.
 484  *
 485  * @domainname: Name of domain.
 486  *
 487  * Returns true if namespace differs, false otherwise.
 488  */
 489 static bool tomoyo_namespace_jump(const char *domainname)
 490 {
 491         const char *namespace = tomoyo_current_namespace()->name;
 492         const int len = strlen(namespace);
 493         return strncmp(domainname, namespace, len) ||
 494                 (domainname[len] && domainname[len] != ' ');
 495 }
 496
 497 /**
 498  * tomoyo_assign_domain - Create a domain or a namespace.
 499  *
 500  * @domainname: The name of domain.
 501  * @transit:    True if transit to domain found or created.
 502  *
 503  * Returns pointer to "struct tomoyo_domain_info" on success, NULL otherwise.
 504  *
 505  * Caller holds tomoyo_read_lock().
 506  */
 507 struct tomoyo_domain_info *tomoyo_assign_domain(const char *domainname,
 508                                                 const bool transit)
 509 {
 510         struct tomoyo_domain_info e = { };
 511         struct tomoyo_domain_info *entry = tomoyo_find_domain(domainname);
 512         bool created = false;
 513         if (entry) {
 514                 if (transit) {
 515                         /*
 516                          * Since namespace is created at runtime, profiles may
 517                          * not be created by the moment the process transits to
 518                          * that domain. Do not perform domain transition if
 519                          * profile for that domain is not yet created.
 520                          */
 521                         if (tomoyo_policy_loaded &&
 522                             !entry->ns->profile_ptr[entry->profile])
 523                                 return NULL;
 524                 }
 525                 return entry;
 526         }
 527         /* Requested domain does not exist. */
 528         /* Don't create requested domain if domainname is invalid. */
 529         if (strlen(domainname) >= TOMOYO_EXEC_TMPSIZE - 10 ||
 530             !tomoyo_correct_domain(domainname))
 531                 return NULL;
 532         /*
 533          * Since definition of profiles and acl_groups may differ across
 534          * namespaces, do not inherit "use_profile" and "use_group" settings
 535          * by automatically creating requested domain upon domain transition.
 536          */
 537         if (transit && tomoyo_namespace_jump(domainname))
 538                 return NULL;
 539         e.ns = tomoyo_assign_namespace(domainname);
 540         if (!e.ns)
 541                 return NULL;
 542         /*
 543          * "use_profile" and "use_group" settings for automatically created
 544          * domains are inherited from current domain. These are 0 for manually
 545          * created domains.
 546          */
 547         if (transit) {
 548                 const struct tomoyo_domain_info *domain = tomoyo_domain();
 549                 e.profile = domain->profile;
 550                 e.group = domain->group;
 551         }
 552         e.domainname = tomoyo_get_name(domainname);
 553         if (!e.domainname)
 554                 return NULL;
 555         if (mutex_lock_interruptible(&tomoyo_policy_lock))
 556                 goto out;
 557         entry = tomoyo_find_domain(domainname);
 558         if (!entry) {
 559                 entry = tomoyo_commit_ok(&e, sizeof(e));
 560                 if (entry) {
 561                         INIT_LIST_HEAD(&entry->acl_info_list);
 562                         list_add_tail_rcu(&entry->list, &tomoyo_domain_list);
 563                         created = true;
 564                 }
 565         }
 566         mutex_unlock(&tomoyo_policy_lock);
 567 out:
 568         tomoyo_put_name(e.domainname);
 569         if (entry && transit) {
 570                 if (created) {
 571                         struct tomoyo_request_info r;
 572                         tomoyo_init_request_info(&r, entry,
 573                                                  TOMOYO_MAC_FILE_EXECUTE);
 574                         r.granted = false;
 575                         tomoyo_write_log(&r, "use_profile %u\n",
 576                                          entry->profile);
 577                         tomoyo_write_log(&r, "use_group %u\n", entry->group);
 578                         tomoyo_update_stat(TOMOYO_STAT_POLICY_UPDATES);
 579                 }
 580         }
 581         return entry;
 582 }
 583
 584 /**
 585  * tomoyo_environ - Check permission for environment variable names.
 586  *
 587  * @ee: Pointer to "struct tomoyo_execve".
 588  *
 589  * Returns 0 on success, negative value otherwise.
 590  */
 591 static int tomoyo_environ(struct tomoyo_execve *ee)
 592 {
 593         struct tomoyo_request_info *r = &ee->r;
 594         struct linux_binprm *bprm = ee->bprm;
 595         /* env_page.data is allocated by tomoyo_dump_page(). */
 596         struct tomoyo_page_dump env_page = { };
 597         char *arg_ptr; /* Size is TOMOYO_EXEC_TMPSIZE bytes */
 598         int arg_len = 0;
 599         unsigned long pos = bprm->p;
 600         int offset = pos % PAGE_SIZE;
 601         int argv_count = bprm->argc;
 602         int envp_count = bprm->envc;
 603         int error = -ENOMEM;
 604
 605         ee->r.type = TOMOYO_MAC_ENVIRON;
 606         ee->r.profile = r->domain->profile;
 607         ee->r.mode = tomoyo_get_mode(r->domain->ns, ee->r.profile,
 608                                      TOMOYO_MAC_ENVIRON);
 609         if (!r->mode || !envp_count)
 610                 return 0;
 611         arg_ptr = kzalloc(TOMOYO_EXEC_TMPSIZE, GFP_NOFS);
 612         if (!arg_ptr)
 613                 goto out;
 614         while (error == -ENOMEM) {
 615                 if (!tomoyo_dump_page(bprm, pos, &env_page))
 616                         goto out;
 617                 pos += PAGE_SIZE - offset;
 618                 /* Read. */
 619                 while (argv_count && offset < PAGE_SIZE) {
 620                         if (!env_page.data[offset++])
 621                                 argv_count--;
 622                 }
 623                 if (argv_count) {
 624                         offset = 0;
 625                         continue;
 626                 }
 627                 while (offset < PAGE_SIZE) {
 628                         const unsigned char c = env_page.data[offset++];
 629
 630                         if (c && arg_len < TOMOYO_EXEC_TMPSIZE - 10) {
 631                                 if (c == '=') {
 632                                         arg_ptr[arg_len++] = '\0';
 633                                 } else if (c == '\\') {
 634                                         arg_ptr[arg_len++] = '\\';
 635                                         arg_ptr[arg_len++] = '\\';
 636                                 } else if (c > ' ' && c < 127) {
 637                                         arg_ptr[arg_len++] = c;
 638                                 } else {
 639                                         arg_ptr[arg_len++] = '\\';
 640                                         arg_ptr[arg_len++] = (c >> 6) + '0';
 641                                         arg_ptr[arg_len++]
 642                                                 = ((c >> 3) & 7) + '0';
 643                                         arg_ptr[arg_len++] = (c & 7) + '0';
 644                                 }
 645                         } else {
 646                                 arg_ptr[arg_len] = '\0';
 647                         }
 648                         if (c)
 649                                 continue;
 650                         if (tomoyo_env_perm(r, arg_ptr)) {
 651                                 error = -EPERM;
 652                                 break;
 653                         }
 654                         if (!--envp_count) {
 655                                 error = 0;
 656                                 break;
 657                         }
 658                         arg_len = 0;
 659                 }
 660                 offset = 0;
 661         }
 662 out:
 663         if (r->mode != TOMOYO_CONFIG_ENFORCING)
 664                 error = 0;
 665         kfree(env_page.data);
 666         kfree(arg_ptr);
 667         return error;
 668 }
 669
 670 /**
 671  * tomoyo_find_next_domain - Find a domain.
 672  *
 673  * @bprm: Pointer to "struct linux_binprm".
 674  *
 675  * Returns 0 on success, negative value otherwise.
 676  *
 677  * Caller holds tomoyo_read_lock().
 678  */
 679 int tomoyo_find_next_domain(struct linux_binprm *bprm)
 680 {
 681         struct tomoyo_domain_info *old_domain = tomoyo_domain();
 682         struct tomoyo_domain_info *domain = NULL;
 683         const char *original_name = bprm->filename;
 684         int retval = -ENOMEM;
 685         bool reject_on_transition_failure = false;
 686         const struct tomoyo_path_info *candidate;
 687         struct tomoyo_path_info exename;
 688         struct tomoyo_execve *ee = kzalloc(sizeof(*ee), GFP_NOFS);
 689
 690         if (!ee)
 691                 return -ENOMEM;
 692         ee->tmp = kzalloc(TOMOYO_EXEC_TMPSIZE, GFP_NOFS);
 693         if (!ee->tmp) {
 694                 kfree(ee);
 695                 return -ENOMEM;
 696         }
 697         /* ee->dump->data is allocated by tomoyo_dump_page(). */
 698         tomoyo_init_request_info(&ee->r, NULL, TOMOYO_MAC_FILE_EXECUTE);
 699         ee->r.ee = ee;
 700         ee->bprm = bprm;
 701         ee->r.obj = &ee->obj;
 702         ee->obj.path1 = bprm->file->f_path;
 703         /* Get symlink's pathname of program. */
 704         retval = -ENOENT;
 705         exename.name = tomoyo_realpath_nofollow(original_name);
 706         if (!exename.name)
 707                 goto out;
 708         tomoyo_fill_path_info(&exename);
 709 retry:
 710         /* Check 'aggregator' directive. */
 711         {
 712                 struct tomoyo_aggregator *ptr;
 713                 struct list_head *list =
 714                         &old_domain->ns->policy_list[TOMOYO_ID_AGGREGATOR];
 715                 /* Check 'aggregator' directive. */
 716                 candidate = &exename;
 717                 list_for_each_entry_rcu(ptr, list, head.list) {
 718                         if (ptr->head.is_deleted ||
 719                             !tomoyo_path_matches_pattern(&exename,
 720                                                          ptr->original_name))
 721                                 continue;
 722                         candidate = ptr->aggregated_name;
 723                         break;
 724                 }
 725         }
 726
 727         /* Check execute permission. */
 728         retval = tomoyo_execute_permission(&ee->r, candidate);
 729         if (retval == TOMOYO_RETRY_REQUEST)
 730                 goto retry;
 731         if (retval < 0)
 732                 goto out;
 733         /*
 734          * To be able to specify domainnames with wildcards, use the
 735          * pathname specified in the policy (which may contain
 736          * wildcard) rather than the pathname passed to execve()
 737          * (which never contains wildcard).
 738          */
 739         if (ee->r.param.path.matched_path)
 740                 candidate = ee->r.param.path.matched_path;
 741
 742         /*
 743          * Check for domain transition preference if "file execute" matched.
 744          * If preference is given, make do_execve() fail if domain transition
 745          * has failed, for domain transition preference should be used with
 746          * destination domain defined.
 747          */
 748         if (ee->transition) {
 749                 const char *domainname = ee->transition->name;
 750                 reject_on_transition_failure = true;
 751                 if (!strcmp(domainname, "keep"))
 752                         goto force_keep_domain;
 753                 if (!strcmp(domainname, "child"))
 754                         goto force_child_domain;
 755                 if (!strcmp(domainname, "reset"))
 756                         goto force_reset_domain;
 757                 if (!strcmp(domainname, "initialize"))
 758                         goto force_initialize_domain;
 759                 if (!strcmp(domainname, "parent")) {
 760                         char *cp;
 761                         strncpy(ee->tmp, old_domain->domainname->name,
 762                                 TOMOYO_EXEC_TMPSIZE - 1);
 763                         cp = strrchr(ee->tmp, ' ');
 764                         if (cp)
 765                                 *cp = '\0';
 766                 } else if (*domainname == '<')
 767                         strncpy(ee->tmp, domainname, TOMOYO_EXEC_TMPSIZE - 1);
 768                 else
 769                         snprintf(ee->tmp, TOMOYO_EXEC_TMPSIZE - 1, "%s %s",
 770                                  old_domain->domainname->name, domainname);
 771                 goto force_jump_domain;
 772         }
 773         /*
 774          * No domain transition preference specified.
 775          * Calculate domain to transit to.
 776          */
 777         switch (tomoyo_transition_type(old_domain->ns, old_domain->domainname,
 778                                        candidate)) {
 779         case TOMOYO_TRANSITION_CONTROL_RESET:
 780 force_reset_domain:
 781                 /* Transit to the root of specified namespace. */
 782                 snprintf(ee->tmp, TOMOYO_EXEC_TMPSIZE - 1, "<%s>",
 783                          candidate->name);
 784                 /*
 785                  * Make do_execve() fail if domain transition across namespaces
 786                  * has failed.
 787                  */
 788                 reject_on_transition_failure = true;
 789                 break;
 790         case TOMOYO_TRANSITION_CONTROL_INITIALIZE:
 791 force_initialize_domain:
 792                 /* Transit to the child of current namespace's root. */
 793                 snprintf(ee->tmp, TOMOYO_EXEC_TMPSIZE - 1, "%s %s",
 794                          old_domain->ns->name, candidate->name);
 795                 break;
 796         case TOMOYO_TRANSITION_CONTROL_KEEP:
 797 force_keep_domain:
 798                 /* Keep current domain. */
 799                 domain = old_domain;
 800                 break;
 801         default:
 802                 if (old_domain == &tomoyo_kernel_domain &&
 803                     !tomoyo_policy_loaded) {
 804                         /*
 805                          * Needn't to transit from kernel domain before
 806                          * starting /sbin/init. But transit from kernel domain
 807                          * if executing initializers because they might start
 808                          * before /sbin/init.
 809                          */
 810                         domain = old_domain;
 811                         break;
 812                 }
 813 force_child_domain:
 814                 /* Normal domain transition. */
 815                 snprintf(ee->tmp, TOMOYO_EXEC_TMPSIZE - 1, "%s %s",
 816                          old_domain->domainname->name, candidate->name);
 817                 break;
 818         }
 819 force_jump_domain:
 820         if (!domain)
 821                 domain = tomoyo_assign_domain(ee->tmp, true);
 822         if (domain)
 823                 retval = 0;
 824         else if (reject_on_transition_failure) {
 825                 printk(KERN_WARNING "ERROR: Domain '%s' not ready.\n",
 826                        ee->tmp);
 827                 retval = -ENOMEM;
 828         } else if (ee->r.mode == TOMOYO_CONFIG_ENFORCING)
 829                 retval = -ENOMEM;
 830         else {
 831                 retval = 0;
 832                 if (!old_domain->flags[TOMOYO_DIF_TRANSITION_FAILED]) {
 833                         old_domain->flags[TOMOYO_DIF_TRANSITION_FAILED] = true;
 834                         ee->r.granted = false;
 835                         tomoyo_write_log(&ee->r, "%s", tomoyo_dif
 836                                          [TOMOYO_DIF_TRANSITION_FAILED]);
 837                         printk(KERN_WARNING
 838                                "ERROR: Domain '%s' not defined.\n", ee->tmp);
 839                 }
 840         }
 841  out:
 842         if (!domain)
 843                 domain = old_domain;
 844         /* Update reference count on "struct tomoyo_domain_info". */
 845         atomic_inc(&domain->users);
 846         bprm->cred->security = domain;
 847         kfree(exename.name);
 848         if (!retval) {
 849                 ee->r.domain = domain;
 850                 retval = tomoyo_environ(ee);
 851         }
 852         kfree(ee->tmp);
 853         kfree(ee->dump.data);
 854         kfree(ee);
 855         return retval;
 856 }
 857
 858 /**
 859  * tomoyo_dump_page - Dump a page to buffer.
 860  *
 861  * @bprm: Pointer to "struct linux_binprm".
 862  * @pos:  Location to dump.
 863  * @dump: Poiner to "struct tomoyo_page_dump".
 864  *
 865  * Returns true on success, false otherwise.
 866  */
 867 bool tomoyo_dump_page(struct linux_binprm *bprm, unsigned long pos,
 868                       struct tomoyo_page_dump *dump)
 869 {
 870         struct page *page;
 871
 872         /* dump->data is released by tomoyo_find_next_domain(). */
 873         if (!dump->data) {
 874                 dump->data = kzalloc(PAGE_SIZE, GFP_NOFS);
 875                 if (!dump->data)
 876                         return false;
 877         }
 878         /* Same with get_arg_page(bprm, pos, 0) in fs/exec.c */
 879 #ifdef CONFIG_MMU
 880         /*
 881          * This is called at execve() time in order to dig around
 882          * in the argv/environment of the new proceess
 883          * (represented by bprm).  'current' is the process doing
 884          * the execve().
 885          */
 886         if (get_user_pages_remote(current, bprm->mm, pos, 1,
 887                                 FOLL_FORCE, &page, NULL, NULL) <= 0)
 888                 return false;
 889 #else
 890         page = bprm->page[pos / PAGE_SIZE];
 891 #endif
 892         if (page != dump->page) {
 893                 const unsigned int offset = pos % PAGE_SIZE;
 894                 /*
 895                  * Maybe kmap()/kunmap() should be used here.
 896                  * But remove_arg_zero() uses kmap_atomic()/kunmap_atomic().
 897                  * So do I.
 898                  */
 899                 char *kaddr = kmap_atomic(page);
 900
 901                 dump->page = page;
 902                 memcpy(dump->data + offset, kaddr + offset,
 903                        PAGE_SIZE - offset);
 904                 kunmap_atomic(kaddr);
 905         }
 906         /* Same with put_arg_page(page) in fs/exec.c */
 907 #ifdef CONFIG_MMU
 908         put_page(page);
 909 #endif
 910         return true;
 911 }