security/tomoyo/domain.c

   1 /*
   2  * security/tomoyo/domain.c
   3  *
   4  * Implementation of the Domain-Based Mandatory Access Control.
   5  *
   6  * Copyright (C) 2005-2009  NTT DATA CORPORATION
   7  *
   8  * Version: 2.2.0   2009/04/01
   9  *
  10  */
  11
  12 #include "common.h"
  13 #include "tomoyo.h"
  14 #include "realpath.h"
  15 #include <linux/binfmts.h>
  16
  17 /* Variables definitions.*/
  18
  19 /* The initial domain. */
  20 struct tomoyo_domain_info tomoyo_kernel_domain;
  21
  22 /* The list for "struct tomoyo_domain_info". */
  23 LIST_HEAD(tomoyo_domain_list);
  24 DECLARE_RWSEM(tomoyo_domain_list_lock);
  25
  26 /* Structure for "initialize_domain" and "no_initialize_domain" keyword. */
  27 struct tomoyo_domain_initializer_entry {
  28         struct list_head list;
  29         const struct tomoyo_path_info *domainname;    /* This may be NULL */
  30         const struct tomoyo_path_info *program;
  31         bool is_deleted;
  32         bool is_not;       /* True if this entry is "no_initialize_domain".  */
  33         /* True if the domainname is tomoyo_get_last_name(). */
  34         bool is_last_name;
  35 };
  36
  37 /* Structure for "keep_domain" and "no_keep_domain" keyword. */
  38 struct tomoyo_domain_keeper_entry {
  39         struct list_head list;
  40         const struct tomoyo_path_info *domainname;
  41         const struct tomoyo_path_info *program;       /* This may be NULL */
  42         bool is_deleted;
  43         bool is_not;       /* True if this entry is "no_keep_domain".        */
  44         /* True if the domainname is tomoyo_get_last_name(). */
  45         bool is_last_name;
  46 };
  47
  48 /* Structure for "alias" keyword. */
  49 struct tomoyo_alias_entry {
  50         struct list_head list;
  51         const struct tomoyo_path_info *original_name;
  52         const struct tomoyo_path_info *aliased_name;
  53         bool is_deleted;
  54 };
  55
  56 /**
  57  * tomoyo_set_domain_flag - Set or clear domain's attribute flags.
  58  *
  59  * @domain:    Pointer to "struct tomoyo_domain_info".
  60  * @is_delete: True if it is a delete request.
  61  * @flags:     Flags to set or clear.
  62  *
  63  * Returns nothing.
  64  */
  65 void tomoyo_set_domain_flag(struct tomoyo_domain_info *domain,
  66                             const bool is_delete, const u8 flags)
  67 {
  68         /* We need to serialize because this is bitfield operation. */
  69         static DEFINE_SPINLOCK(lock);
  70         /***** CRITICAL SECTION START *****/
  71         spin_lock(&lock);
  72         if (!is_delete)
  73                 domain->flags |= flags;
  74         else
  75                 domain->flags &= ~flags;
  76         spin_unlock(&lock);
  77         /***** CRITICAL SECTION END *****/
  78 }
  79
  80 /**
  81  * tomoyo_get_last_name - Get last component of a domainname.
  82  *
  83  * @domain: Pointer to "struct tomoyo_domain_info".
  84  *
  85  * Returns the last component of the domainname.
  86  */
  87 const char *tomoyo_get_last_name(const struct tomoyo_domain_info *domain)
  88 {
  89         const char *cp0 = domain->domainname->name;
  90         const char *cp1 = strrchr(cp0, ' ');
  91
  92         if (cp1)
  93                 return cp1 + 1;
  94         return cp0;
  95 }
  96
  97 /* The list for "struct tomoyo_domain_initializer_entry". */
  98 static LIST_HEAD(tomoyo_domain_initializer_list);
  99 static DECLARE_RWSEM(tomoyo_domain_initializer_list_lock);
 100
 101 /**
 102  * tomoyo_update_domain_initializer_entry - Update "struct tomoyo_domain_initializer_entry" list.
 103  *
 104  * @domainname: The name of domain. May be NULL.
 105  * @program:    The name of program.
 106  * @is_not:     True if it is "no_initialize_domain" entry.
 107  * @is_delete:  True if it is a delete request.
 108  *
 109  * Returns 0 on success, negative value otherwise.
 110  */
 111 static int tomoyo_update_domain_initializer_entry(const char *domainname,
 112                                                   const char *program,
 113                                                   const bool is_not,
 114                                                   const bool is_delete)
 115 {
 116         struct tomoyo_domain_initializer_entry *new_entry;
 117         struct tomoyo_domain_initializer_entry *ptr;
 118         const struct tomoyo_path_info *saved_program;
 119         const struct tomoyo_path_info *saved_domainname = NULL;
 120         int error = -ENOMEM;
 121         bool is_last_name = false;
 122
 123         if (!tomoyo_is_correct_path(program, 1, -1, -1, __func__))
 124                 return -EINVAL; /* No patterns allowed. */
 125         if (domainname) {
 126                 if (!tomoyo_is_domain_def(domainname) &&
 127                     tomoyo_is_correct_path(domainname, 1, -1, -1, __func__))
 128                         is_last_name = true;
 129                 else if (!tomoyo_is_correct_domain(domainname, __func__))
 130                         return -EINVAL;
 131                 saved_domainname = tomoyo_save_name(domainname);
 132                 if (!saved_domainname)
 133                         return -ENOMEM;
 134         }
 135         saved_program = tomoyo_save_name(program);
 136         if (!saved_program)
 137                 return -ENOMEM;
 138         /***** EXCLUSIVE SECTION START *****/
 139         down_write(&tomoyo_domain_initializer_list_lock);
 140         list_for_each_entry(ptr, &tomoyo_domain_initializer_list, list) {
 141                 if (ptr->is_not != is_not ||
 142                     ptr->domainname != saved_domainname ||
 143                     ptr->program != saved_program)
 144                         continue;
 145                 ptr->is_deleted = is_delete;
 146                 error = 0;
 147                 goto out;
 148         }
 149         if (is_delete) {
 150                 error = -ENOENT;
 151                 goto out;
 152         }
 153         new_entry = tomoyo_alloc_element(sizeof(*new_entry));
 154         if (!new_entry)
 155                 goto out;
 156         new_entry->domainname = saved_domainname;
 157         new_entry->program = saved_program;
 158         new_entry->is_not = is_not;
 159         new_entry->is_last_name = is_last_name;
 160         list_add_tail(&new_entry->list, &tomoyo_domain_initializer_list);
 161         error = 0;
 162  out:
 163         up_write(&tomoyo_domain_initializer_list_lock);
 164         /***** EXCLUSIVE SECTION END *****/
 165         return error;
 166 }
 167
 168 /**
 169  * tomoyo_read_domain_initializer_policy - Read "struct tomoyo_domain_initializer_entry" list.
 170  *
 171  * @head: Pointer to "struct tomoyo_io_buffer".
 172  *
 173  * Returns true on success, false otherwise.
 174  */
 175 bool tomoyo_read_domain_initializer_policy(struct tomoyo_io_buffer *head)
 176 {
 177         struct list_head *pos;
 178         bool done = true;
 179
 180         down_read(&tomoyo_domain_initializer_list_lock);
 181         list_for_each_cookie(pos, head->read_var2,
 182                              &tomoyo_domain_initializer_list) {
 183                 const char *no;
 184                 const char *from = "";
 185                 const char *domain = "";
 186                 struct tomoyo_domain_initializer_entry *ptr;
 187                 ptr = list_entry(pos, struct tomoyo_domain_initializer_entry,
 188                                   list);
 189                 if (ptr->is_deleted)
 190                         continue;
 191                 no = ptr->is_not ? "no_" : "";
 192                 if (ptr->domainname) {
 193                         from = " from ";
 194                         domain = ptr->domainname->name;
 195                 }
 196                 if (!tomoyo_io_printf(head,
 197                                       "%s" TOMOYO_KEYWORD_INITIALIZE_DOMAIN
 198                                       "%s%s%s\n", no, ptr->program->name, from,
 199                                       domain)) {
 200                         done = false;
 201                         break;
 202                 }
 203         }
 204         up_read(&tomoyo_domain_initializer_list_lock);
 205         return done;
 206 }
 207
 208 /**
 209  * tomoyo_write_domain_initializer_policy - Write "struct tomoyo_domain_initializer_entry" list.
 210  *
 211  * @data:      String to parse.
 212  * @is_not:    True if it is "no_initialize_domain" entry.
 213  * @is_delete: True if it is a delete request.
 214  *
 215  * Returns 0 on success, negative value otherwise.
 216  */
 217 int tomoyo_write_domain_initializer_policy(char *data, const bool is_not,
 218                                            const bool is_delete)
 219 {
 220         char *cp = strstr(data, " from ");
 221
 222         if (cp) {
 223                 *cp = '\0';
 224                 return tomoyo_update_domain_initializer_entry(cp + 6, data,
 225                                                               is_not,
 226                                                               is_delete);
 227         }
 228         return tomoyo_update_domain_initializer_entry(NULL, data, is_not,
 229                                                       is_delete);
 230 }
 231
 232 /**
 233  * tomoyo_is_domain_initializer - Check whether the given program causes domainname reinitialization.
 234  *
 235  * @domainname: The name of domain.
 236  * @program:    The name of program.
 237  * @last_name:  The last component of @domainname.
 238  *
 239  * Returns true if executing @program reinitializes domain transition,
 240  * false otherwise.
 241  */
 242 static bool tomoyo_is_domain_initializer(const struct tomoyo_path_info *
 243                                          domainname,
 244                                          const struct tomoyo_path_info *program,
 245                                          const struct tomoyo_path_info *
 246                                          last_name)
 247 {
 248         struct tomoyo_domain_initializer_entry *ptr;
 249         bool flag = false;
 250
 251         down_read(&tomoyo_domain_initializer_list_lock);
 252         list_for_each_entry(ptr,  &tomoyo_domain_initializer_list, list) {
 253                 if (ptr->is_deleted)
 254                         continue;
 255                 if (ptr->domainname) {
 256                         if (!ptr->is_last_name) {
 257                                 if (ptr->domainname != domainname)
 258                                         continue;
 259                         } else {
 260                                 if (tomoyo_pathcmp(ptr->domainname, last_name))
 261                                         continue;
 262                         }
 263                 }
 264                 if (tomoyo_pathcmp(ptr->program, program))
 265                         continue;
 266                 if (ptr->is_not) {
 267                         flag = false;
 268                         break;
 269                 }
 270                 flag = true;
 271         }
 272         up_read(&tomoyo_domain_initializer_list_lock);
 273         return flag;
 274 }
 275
 276 /* The list for "struct tomoyo_domain_keeper_entry". */
 277 static LIST_HEAD(tomoyo_domain_keeper_list);
 278 static DECLARE_RWSEM(tomoyo_domain_keeper_list_lock);
 279
 280 /**
 281  * tomoyo_update_domain_keeper_entry - Update "struct tomoyo_domain_keeper_entry" list.
 282  *
 283  * @domainname: The name of domain.
 284  * @program:    The name of program. May be NULL.
 285  * @is_not:     True if it is "no_keep_domain" entry.
 286  * @is_delete:  True if it is a delete request.
 287  *
 288  * Returns 0 on success, negative value otherwise.
 289  */
 290 static int tomoyo_update_domain_keeper_entry(const char *domainname,
 291                                              const char *program,
 292                                              const bool is_not,
 293                                              const bool is_delete)
 294 {
 295         struct tomoyo_domain_keeper_entry *new_entry;
 296         struct tomoyo_domain_keeper_entry *ptr;
 297         const struct tomoyo_path_info *saved_domainname;
 298         const struct tomoyo_path_info *saved_program = NULL;
 299         static DEFINE_MUTEX(lock);
 300         int error = -ENOMEM;
 301         bool is_last_name = false;
 302
 303         if (!tomoyo_is_domain_def(domainname) &&
 304             tomoyo_is_correct_path(domainname, 1, -1, -1, __func__))
 305                 is_last_name = true;
 306         else if (!tomoyo_is_correct_domain(domainname, __func__))
 307                 return -EINVAL;
 308         if (program) {
 309                 if (!tomoyo_is_correct_path(program, 1, -1, -1, __func__))
 310                         return -EINVAL;
 311                 saved_program = tomoyo_save_name(program);
 312                 if (!saved_program)
 313                         return -ENOMEM;
 314         }
 315         saved_domainname = tomoyo_save_name(domainname);
 316         if (!saved_domainname)
 317                 return -ENOMEM;
 318         /***** EXCLUSIVE SECTION START *****/
 319         down_write(&tomoyo_domain_keeper_list_lock);
 320         list_for_each_entry(ptr, &tomoyo_domain_keeper_list, list) {
 321                 if (ptr->is_not != is_not ||
 322                     ptr->domainname != saved_domainname ||
 323                     ptr->program != saved_program)
 324                         continue;
 325                 ptr->is_deleted = is_delete;
 326                 error = 0;
 327                 goto out;
 328         }
 329         if (is_delete) {
 330                 error = -ENOENT;
 331                 goto out;
 332         }
 333         new_entry = tomoyo_alloc_element(sizeof(*new_entry));
 334         if (!new_entry)
 335                 goto out;
 336         new_entry->domainname = saved_domainname;
 337         new_entry->program = saved_program;
 338         new_entry->is_not = is_not;
 339         new_entry->is_last_name = is_last_name;
 340         list_add_tail(&new_entry->list, &tomoyo_domain_keeper_list);
 341         error = 0;
 342  out:
 343         up_write(&tomoyo_domain_keeper_list_lock);
 344         /***** EXCLUSIVE SECTION END *****/
 345         return error;
 346 }
 347
 348 /**
 349  * tomoyo_write_domain_keeper_policy - Write "struct tomoyo_domain_keeper_entry" list.
 350  *
 351  * @data:      String to parse.
 352  * @is_not:    True if it is "no_keep_domain" entry.
 353  * @is_delete: True if it is a delete request.
 354  *
 355  */
 356 int tomoyo_write_domain_keeper_policy(char *data, const bool is_not,
 357                                       const bool is_delete)
 358 {
 359         char *cp = strstr(data, " from ");
 360
 361         if (cp) {
 362                 *cp = '\0';
 363                 return tomoyo_update_domain_keeper_entry(cp + 6, data, is_not,
 364                                                          is_delete);
 365         }
 366         return tomoyo_update_domain_keeper_entry(data, NULL, is_not, is_delete);
 367 }
 368
 369 /**
 370  * tomoyo_read_domain_keeper_policy - Read "struct tomoyo_domain_keeper_entry" list.
 371  *
 372  * @head: Pointer to "struct tomoyo_io_buffer".
 373  *
 374  * Returns true on success, false otherwise.
 375  */
 376 bool tomoyo_read_domain_keeper_policy(struct tomoyo_io_buffer *head)
 377 {
 378         struct list_head *pos;
 379         bool done = true;
 380
 381         down_read(&tomoyo_domain_keeper_list_lock);
 382         list_for_each_cookie(pos, head->read_var2,
 383                              &tomoyo_domain_keeper_list) {
 384                 struct tomoyo_domain_keeper_entry *ptr;
 385                 const char *no;
 386                 const char *from = "";
 387                 const char *program = "";
 388
 389                 ptr = list_entry(pos, struct tomoyo_domain_keeper_entry, list);
 390                 if (ptr->is_deleted)
 391                         continue;
 392                 no = ptr->is_not ? "no_" : "";
 393                 if (ptr->program) {
 394                         from = " from ";
 395                         program = ptr->program->name;
 396                 }
 397                 if (!tomoyo_io_printf(head,
 398                                       "%s" TOMOYO_KEYWORD_KEEP_DOMAIN
 399                                       "%s%s%s\n", no, program, from,
 400                                       ptr->domainname->name)) {
 401                         done = false;
 402                         break;
 403                 }
 404         }
 405         up_read(&tomoyo_domain_keeper_list_lock);
 406         return done;
 407 }
 408
 409 /**
 410  * tomoyo_is_domain_keeper - Check whether the given program causes domain transition suppression.
 411  *
 412  * @domainname: The name of domain.
 413  * @program:    The name of program.
 414  * @last_name:  The last component of @domainname.
 415  *
 416  * Returns true if executing @program supresses domain transition,
 417  * false otherwise.
 418  */
 419 static bool tomoyo_is_domain_keeper(const struct tomoyo_path_info *domainname,
 420                                     const struct tomoyo_path_info *program,
 421                                     const struct tomoyo_path_info *last_name)
 422 {
 423         struct tomoyo_domain_keeper_entry *ptr;
 424         bool flag = false;
 425
 426         down_read(&tomoyo_domain_keeper_list_lock);
 427         list_for_each_entry(ptr, &tomoyo_domain_keeper_list, list) {
 428                 if (ptr->is_deleted)
 429                         continue;
 430                 if (!ptr->is_last_name) {
 431                         if (ptr->domainname != domainname)
 432                                 continue;
 433                 } else {
 434                         if (tomoyo_pathcmp(ptr->domainname, last_name))
 435                                 continue;
 436                 }
 437                 if (ptr->program && tomoyo_pathcmp(ptr->program, program))
 438                         continue;
 439                 if (ptr->is_not) {
 440                         flag = false;
 441                         break;
 442                 }
 443                 flag = true;
 444         }
 445         up_read(&tomoyo_domain_keeper_list_lock);
 446         return flag;
 447 }
 448
 449 /* The list for "struct tomoyo_alias_entry". */
 450 static LIST_HEAD(tomoyo_alias_list);
 451 static DECLARE_RWSEM(tomoyo_alias_list_lock);
 452
 453 /**
 454  * tomoyo_update_alias_entry - Update "struct tomoyo_alias_entry" list.
 455  *
 456  * @original_name: The original program's real name.
 457  * @aliased_name:  The symbolic program's symbolic link's name.
 458  * @is_delete:     True if it is a delete request.
 459  *
 460  * Returns 0 on success, negative value otherwise.
 461  */
 462 static int tomoyo_update_alias_entry(const char *original_name,
 463                                      const char *aliased_name,
 464                                      const bool is_delete)
 465 {
 466         struct tomoyo_alias_entry *new_entry;
 467         struct tomoyo_alias_entry *ptr;
 468         const struct tomoyo_path_info *saved_original_name;
 469         const struct tomoyo_path_info *saved_aliased_name;
 470         int error = -ENOMEM;
 471
 472         if (!tomoyo_is_correct_path(original_name, 1, -1, -1, __func__) ||
 473             !tomoyo_is_correct_path(aliased_name, 1, -1, -1, __func__))
 474                 return -EINVAL; /* No patterns allowed. */
 475         saved_original_name = tomoyo_save_name(original_name);
 476         saved_aliased_name = tomoyo_save_name(aliased_name);
 477         if (!saved_original_name || !saved_aliased_name)
 478                 return -ENOMEM;
 479         /***** EXCLUSIVE SECTION START *****/
 480         down_write(&tomoyo_alias_list_lock);
 481         list_for_each_entry(ptr, &tomoyo_alias_list, list) {
 482                 if (ptr->original_name != saved_original_name ||
 483                     ptr->aliased_name != saved_aliased_name)
 484                         continue;
 485                 ptr->is_deleted = is_delete;
 486                 error = 0;
 487                 goto out;
 488         }
 489         if (is_delete) {
 490                 error = -ENOENT;
 491                 goto out;
 492         }
 493         new_entry = tomoyo_alloc_element(sizeof(*new_entry));
 494         if (!new_entry)
 495                 goto out;
 496         new_entry->original_name = saved_original_name;
 497         new_entry->aliased_name = saved_aliased_name;
 498         list_add_tail(&new_entry->list, &tomoyo_alias_list);
 499         error = 0;
 500  out:
 501         up_write(&tomoyo_alias_list_lock);
 502         /***** EXCLUSIVE SECTION END *****/
 503         return error;
 504 }
 505
 506 /**
 507  * tomoyo_read_alias_policy - Read "struct tomoyo_alias_entry" list.
 508  *
 509  * @head: Pointer to "struct tomoyo_io_buffer".
 510  *
 511  * Returns true on success, false otherwise.
 512  */
 513 bool tomoyo_read_alias_policy(struct tomoyo_io_buffer *head)
 514 {
 515         struct list_head *pos;
 516         bool done = true;
 517
 518         down_read(&tomoyo_alias_list_lock);
 519         list_for_each_cookie(pos, head->read_var2, &tomoyo_alias_list) {
 520                 struct tomoyo_alias_entry *ptr;
 521
 522                 ptr = list_entry(pos, struct tomoyo_alias_entry, list);
 523                 if (ptr->is_deleted)
 524                         continue;
 525                 if (!tomoyo_io_printf(head, TOMOYO_KEYWORD_ALIAS "%s %s\n",
 526                                       ptr->original_name->name,
 527                                       ptr->aliased_name->name)) {
 528                         done = false;
 529                         break;
 530                 }
 531         }
 532         up_read(&tomoyo_alias_list_lock);
 533         return done;
 534 }
 535
 536 /**
 537  * tomoyo_write_alias_policy - Write "struct tomoyo_alias_entry" list.
 538  *
 539  * @data:      String to parse.
 540  * @is_delete: True if it is a delete request.
 541  *
 542  * Returns 0 on success, negative value otherwise.
 543  */
 544 int tomoyo_write_alias_policy(char *data, const bool is_delete)
 545 {
 546         char *cp = strchr(data, ' ');
 547
 548         if (!cp)
 549                 return -EINVAL;
 550         *cp++ = '\0';
 551         return tomoyo_update_alias_entry(data, cp, is_delete);
 552 }
 553
 554 /* Domain create/delete handler. */
 555
 556 /**
 557  * tomoyo_delete_domain - Delete a domain.
 558  *
 559  * @domainname: The name of domain.
 560  *
 561  * Returns 0.
 562  */
 563 int tomoyo_delete_domain(char *domainname)
 564 {
 565         struct tomoyo_domain_info *domain;
 566         struct tomoyo_path_info name;
 567
 568         name.name = domainname;
 569         tomoyo_fill_path_info(&name);
 570         /***** EXCLUSIVE SECTION START *****/
 571         down_write(&tomoyo_domain_list_lock);
 572         /* Is there an active domain? */
 573         list_for_each_entry(domain, &tomoyo_domain_list, list) {
 574                 /* Never delete tomoyo_kernel_domain */
 575                 if (domain == &tomoyo_kernel_domain)
 576                         continue;
 577                 if (domain->is_deleted ||
 578                     tomoyo_pathcmp(domain->domainname, &name))
 579                         continue;
 580                 domain->is_deleted = true;
 581                 break;
 582         }
 583         up_write(&tomoyo_domain_list_lock);
 584         /***** EXCLUSIVE SECTION END *****/
 585         return 0;
 586 }
 587
 588 /**
 589  * tomoyo_find_or_assign_new_domain - Create a domain.
 590  *
 591  * @domainname: The name of domain.
 592  * @profile:    Profile number to assign if the domain was newly created.
 593  *
 594  * Returns pointer to "struct tomoyo_domain_info" on success, NULL otherwise.
 595  */
 596 struct tomoyo_domain_info *tomoyo_find_or_assign_new_domain(const char *
 597                                                             domainname,
 598                                                             const u8 profile)
 599 {
 600         struct tomoyo_domain_info *domain = NULL;
 601         const struct tomoyo_path_info *saved_domainname;
 602
 603         /***** EXCLUSIVE SECTION START *****/
 604         down_write(&tomoyo_domain_list_lock);
 605         domain = tomoyo_find_domain(domainname);
 606         if (domain)
 607                 goto out;
 608         if (!tomoyo_is_correct_domain(domainname, __func__))
 609                 goto out;
 610         saved_domainname = tomoyo_save_name(domainname);
 611         if (!saved_domainname)
 612                 goto out;
 613         /* Can I reuse memory of deleted domain? */
 614         list_for_each_entry(domain, &tomoyo_domain_list, list) {
 615                 struct task_struct *p;
 616                 struct tomoyo_acl_info *ptr;
 617                 bool flag;
 618                 if (!domain->is_deleted ||
 619                     domain->domainname != saved_domainname)
 620                         continue;
 621                 flag = false;
 622                 /***** CRITICAL SECTION START *****/
 623                 read_lock(&tasklist_lock);
 624                 for_each_process(p) {
 625                         if (tomoyo_real_domain(p) != domain)
 626                                 continue;
 627                         flag = true;
 628                         break;
 629                 }
 630                 read_unlock(&tasklist_lock);
 631                 /***** CRITICAL SECTION END *****/
 632                 if (flag)
 633                         continue;
 634                 list_for_each_entry(ptr, &domain->acl_info_list, list) {
 635                         ptr->type |= TOMOYO_ACL_DELETED;
 636                 }
 637                 tomoyo_set_domain_flag(domain, true, domain->flags);
 638                 domain->profile = profile;
 639                 domain->quota_warned = false;
 640                 mb(); /* Avoid out-of-order execution. */
 641                 domain->is_deleted = false;
 642                 goto out;
 643         }
 644         /* No memory reusable. Create using new memory. */
 645         domain = tomoyo_alloc_element(sizeof(*domain));
 646         if (domain) {
 647                 INIT_LIST_HEAD(&domain->acl_info_list);
 648                 domain->domainname = saved_domainname;
 649                 domain->profile = profile;
 650                 list_add_tail(&domain->list, &tomoyo_domain_list);
 651         }
 652  out:
 653         up_write(&tomoyo_domain_list_lock);
 654         /***** EXCLUSIVE SECTION END *****/
 655         return domain;
 656 }
 657
 658 /**
 659  * tomoyo_find_next_domain - Find a domain.
 660  *
 661  * @bprm:           Pointer to "struct linux_binprm".
 662  * @next_domain:    Pointer to pointer to "struct tomoyo_domain_info".
 663  *
 664  * Returns 0 on success, negative value otherwise.
 665  */
 666 int tomoyo_find_next_domain(struct linux_binprm *bprm,
 667                             struct tomoyo_domain_info **next_domain)
 668 {
 669         /*
 670          * This function assumes that the size of buffer returned by
 671          * tomoyo_realpath() = TOMOYO_MAX_PATHNAME_LEN.
 672          */
 673         struct tomoyo_page_buffer *tmp = tomoyo_alloc(sizeof(*tmp));
 674         struct tomoyo_domain_info *old_domain = tomoyo_domain();
 675         struct tomoyo_domain_info *domain = NULL;
 676         const char *old_domain_name = old_domain->domainname->name;
 677         const char *original_name = bprm->filename;
 678         char *new_domain_name = NULL;
 679         char *real_program_name = NULL;
 680         char *symlink_program_name = NULL;
 681         const u8 mode = tomoyo_check_flags(old_domain, TOMOYO_MAC_FOR_FILE);
 682         const bool is_enforce = (mode == 3);
 683         int retval = -ENOMEM;
 684         struct tomoyo_path_info r; /* real name */
 685         struct tomoyo_path_info s; /* symlink name */
 686         struct tomoyo_path_info l; /* last name */
 687         static bool initialized;
 688
 689         if (!tmp)
 690                 goto out;
 691
 692         if (!initialized) {
 693                 /*
 694                  * Built-in initializers. This is needed because policies are
 695                  * not loaded until starting /sbin/init.
 696                  */
 697                 tomoyo_update_domain_initializer_entry(NULL, "/sbin/hotplug",
 698                                                        false, false);
 699                 tomoyo_update_domain_initializer_entry(NULL, "/sbin/modprobe",
 700                                                        false, false);
 701                 initialized = true;
 702         }
 703
 704         /* Get tomoyo_realpath of program. */
 705         retval = -ENOENT;
 706         /* I hope tomoyo_realpath() won't fail with -ENOMEM. */
 707         real_program_name = tomoyo_realpath(original_name);
 708         if (!real_program_name)
 709                 goto out;
 710         /* Get tomoyo_realpath of symbolic link. */
 711         symlink_program_name = tomoyo_realpath_nofollow(original_name);
 712         if (!symlink_program_name)
 713                 goto out;
 714
 715         r.name = real_program_name;
 716         tomoyo_fill_path_info(&r);
 717         s.name = symlink_program_name;
 718         tomoyo_fill_path_info(&s);
 719         l.name = tomoyo_get_last_name(old_domain);
 720         tomoyo_fill_path_info(&l);
 721
 722         /* Check 'alias' directive. */
 723         if (tomoyo_pathcmp(&r, &s)) {
 724                 struct tomoyo_alias_entry *ptr;
 725                 /* Is this program allowed to be called via symbolic links? */
 726                 down_read(&tomoyo_alias_list_lock);
 727                 list_for_each_entry(ptr, &tomoyo_alias_list, list) {
 728                         if (ptr->is_deleted ||
 729                             tomoyo_pathcmp(&r, ptr->original_name) ||
 730                             tomoyo_pathcmp(&s, ptr->aliased_name))
 731                                 continue;
 732                         memset(real_program_name, 0, TOMOYO_MAX_PATHNAME_LEN);
 733                         strncpy(real_program_name, ptr->aliased_name->name,
 734                                 TOMOYO_MAX_PATHNAME_LEN - 1);
 735                         tomoyo_fill_path_info(&r);
 736                         break;
 737                 }
 738                 up_read(&tomoyo_alias_list_lock);
 739         }
 740
 741         /* Check execute permission. */
 742         retval = tomoyo_check_exec_perm(old_domain, &r, tmp);
 743         if (retval < 0)
 744                 goto out;
 745
 746         new_domain_name = tmp->buffer;
 747         if (tomoyo_is_domain_initializer(old_domain->domainname, &r, &l)) {
 748                 /* Transit to the child of tomoyo_kernel_domain domain. */
 749                 snprintf(new_domain_name, TOMOYO_MAX_PATHNAME_LEN + 1,
 750                          TOMOYO_ROOT_NAME " " "%s", real_program_name);
 751         } else if (old_domain == &tomoyo_kernel_domain &&
 752                    !tomoyo_policy_loaded) {
 753                 /*
 754                  * Needn't to transit from kernel domain before starting
 755                  * /sbin/init. But transit from kernel domain if executing
 756                  * initializers because they might start before /sbin/init.
 757                  */
 758                 domain = old_domain;
 759         } else if (tomoyo_is_domain_keeper(old_domain->domainname, &r, &l)) {
 760                 /* Keep current domain. */
 761                 domain = old_domain;
 762         } else {
 763                 /* Normal domain transition. */
 764                 snprintf(new_domain_name, TOMOYO_MAX_PATHNAME_LEN + 1,
 765                          "%s %s", old_domain_name, real_program_name);
 766         }
 767         if (domain || strlen(new_domain_name) >= TOMOYO_MAX_PATHNAME_LEN)
 768                 goto done;
 769         down_read(&tomoyo_domain_list_lock);
 770         domain = tomoyo_find_domain(new_domain_name);
 771         up_read(&tomoyo_domain_list_lock);
 772         if (domain)
 773                 goto done;
 774         if (is_enforce)
 775                 goto done;
 776         domain = tomoyo_find_or_assign_new_domain(new_domain_name,
 777                                                   old_domain->profile);
 778  done:
 779         if (domain)
 780                 goto out;
 781         printk(KERN_WARNING "TOMOYO-ERROR: Domain '%s' not defined.\n",
 782                new_domain_name);
 783         if (is_enforce)
 784                 retval = -EPERM;
 785         else
 786                 tomoyo_set_domain_flag(old_domain, false,
 787                                        TOMOYO_DOMAIN_FLAGS_TRANSITION_FAILED);
 788  out:
 789         tomoyo_free(real_program_name);
 790         tomoyo_free(symlink_program_name);
 791         *next_domain = domain ? domain : old_domain;
 792         tomoyo_free(tmp);
 793         return retval;
 794 }