git.oblomov.eu Git - linux-2.6/blob - 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         int error = -ENOMEM;
 300         bool is_last_name = false;
 301
 302         if (!tomoyo_is_domain_def(domainname) &&
 303             tomoyo_is_correct_path(domainname, 1, -1, -1, __func__))
 304                 is_last_name = true;
 305         else if (!tomoyo_is_correct_domain(domainname, __func__))
 306                 return -EINVAL;
 307         if (program) {
 308                 if (!tomoyo_is_correct_path(program, 1, -1, -1, __func__))
 309                         return -EINVAL;
 310                 saved_program = tomoyo_save_name(program);
 311                 if (!saved_program)
 312                         return -ENOMEM;
 313         }
 314         saved_domainname = tomoyo_save_name(domainname);
 315         if (!saved_domainname)
 316                 return -ENOMEM;
 317         /***** EXCLUSIVE SECTION START *****/
 318         down_write(&tomoyo_domain_keeper_list_lock);
 319         list_for_each_entry(ptr, &tomoyo_domain_keeper_list, list) {
 320                 if (ptr->is_not != is_not ||
 321                     ptr->domainname != saved_domainname ||
 322                     ptr->program != saved_program)
 323                         continue;
 324                 ptr->is_deleted = is_delete;
 325                 error = 0;
 326                 goto out;
 327         }
 328         if (is_delete) {
 329                 error = -ENOENT;
 330                 goto out;
 331         }
 332         new_entry = tomoyo_alloc_element(sizeof(*new_entry));
 333         if (!new_entry)
 334                 goto out;
 335         new_entry->domainname = saved_domainname;
 336         new_entry->program = saved_program;
 337         new_entry->is_not = is_not;
 338         new_entry->is_last_name = is_last_name;
 339         list_add_tail(&new_entry->list, &tomoyo_domain_keeper_list);
 340         error = 0;
 341  out:
 342         up_write(&tomoyo_domain_keeper_list_lock);
 343         /***** EXCLUSIVE SECTION END *****/
 344         return error;
 345 }
 346
 347 /**
 348  * tomoyo_write_domain_keeper_policy - Write "struct tomoyo_domain_keeper_entry" list.
 349  *
 350  * @data:      String to parse.
 351  * @is_not:    True if it is "no_keep_domain" entry.
 352  * @is_delete: True if it is a delete request.
 353  *
 354  */
 355 int tomoyo_write_domain_keeper_policy(char *data, const bool is_not,
 356                                       const bool is_delete)
 357 {
 358         char *cp = strstr(data, " from ");
 359
 360         if (cp) {
 361                 *cp = '\0';
 362                 return tomoyo_update_domain_keeper_entry(cp + 6, data, is_not,
 363                                                          is_delete);
 364         }
 365         return tomoyo_update_domain_keeper_entry(data, NULL, is_not, is_delete);
 366 }
 367
 368 /**
 369  * tomoyo_read_domain_keeper_policy - Read "struct tomoyo_domain_keeper_entry" list.
 370  *
 371  * @head: Pointer to "struct tomoyo_io_buffer".
 372  *
 373  * Returns true on success, false otherwise.
 374  */
 375 bool tomoyo_read_domain_keeper_policy(struct tomoyo_io_buffer *head)
 376 {
 377         struct list_head *pos;
 378         bool done = true;
 379
 380         down_read(&tomoyo_domain_keeper_list_lock);
 381         list_for_each_cookie(pos, head->read_var2,
 382                              &tomoyo_domain_keeper_list) {
 383                 struct tomoyo_domain_keeper_entry *ptr;
 384                 const char *no;
 385                 const char *from = "";
 386                 const char *program = "";
 387
 388                 ptr = list_entry(pos, struct tomoyo_domain_keeper_entry, list);
 389                 if (ptr->is_deleted)
 390                         continue;
 391                 no = ptr->is_not ? "no_" : "";
 392                 if (ptr->program) {
 393                         from = " from ";
 394                         program = ptr->program->name;
 395                 }
 396                 if (!tomoyo_io_printf(head,
 397                                       "%s" TOMOYO_KEYWORD_KEEP_DOMAIN
 398                                       "%s%s%s\n", no, program, from,
 399                                       ptr->domainname->name)) {
 400                         done = false;
 401                         break;
 402                 }
 403         }
 404         up_read(&tomoyo_domain_keeper_list_lock);
 405         return done;
 406 }
 407
 408 /**
 409  * tomoyo_is_domain_keeper - Check whether the given program causes domain transition suppression.
 410  *
 411  * @domainname: The name of domain.
 412  * @program:    The name of program.
 413  * @last_name:  The last component of @domainname.
 414  *
 415  * Returns true if executing @program supresses domain transition,
 416  * false otherwise.
 417  */
 418 static bool tomoyo_is_domain_keeper(const struct tomoyo_path_info *domainname,
 419                                     const struct tomoyo_path_info *program,
 420                                     const struct tomoyo_path_info *last_name)
 421 {
 422         struct tomoyo_domain_keeper_entry *ptr;
 423         bool flag = false;
 424
 425         down_read(&tomoyo_domain_keeper_list_lock);
 426         list_for_each_entry(ptr, &tomoyo_domain_keeper_list, list) {
 427                 if (ptr->is_deleted)
 428                         continue;
 429                 if (!ptr->is_last_name) {
 430                         if (ptr->domainname != domainname)
 431                                 continue;
 432                 } else {
 433                         if (tomoyo_pathcmp(ptr->domainname, last_name))
 434                                 continue;
 435                 }
 436                 if (ptr->program && tomoyo_pathcmp(ptr->program, program))
 437                         continue;
 438                 if (ptr->is_not) {
 439                         flag = false;
 440                         break;
 441                 }
 442                 flag = true;
 443         }
 444         up_read(&tomoyo_domain_keeper_list_lock);
 445         return flag;
 446 }
 447
 448 /* The list for "struct tomoyo_alias_entry". */
 449 static LIST_HEAD(tomoyo_alias_list);
 450 static DECLARE_RWSEM(tomoyo_alias_list_lock);
 451
 452 /**
 453  * tomoyo_update_alias_entry - Update "struct tomoyo_alias_entry" list.
 454  *
 455  * @original_name: The original program's real name.
 456  * @aliased_name:  The symbolic program's symbolic link's name.
 457  * @is_delete:     True if it is a delete request.
 458  *
 459  * Returns 0 on success, negative value otherwise.
 460  */
 461 static int tomoyo_update_alias_entry(const char *original_name,
 462                                      const char *aliased_name,
 463                                      const bool is_delete)
 464 {
 465         struct tomoyo_alias_entry *new_entry;
 466         struct tomoyo_alias_entry *ptr;
 467         const struct tomoyo_path_info *saved_original_name;
 468         const struct tomoyo_path_info *saved_aliased_name;
 469         int error = -ENOMEM;
 470
 471         if (!tomoyo_is_correct_path(original_name, 1, -1, -1, __func__) ||
 472             !tomoyo_is_correct_path(aliased_name, 1, -1, -1, __func__))
 473                 return -EINVAL; /* No patterns allowed. */
 474         saved_original_name = tomoyo_save_name(original_name);
 475         saved_aliased_name = tomoyo_save_name(aliased_name);
 476         if (!saved_original_name || !saved_aliased_name)
 477                 return -ENOMEM;
 478         /***** EXCLUSIVE SECTION START *****/
 479         down_write(&tomoyo_alias_list_lock);
 480         list_for_each_entry(ptr, &tomoyo_alias_list, list) {
 481                 if (ptr->original_name != saved_original_name ||
 482                     ptr->aliased_name != saved_aliased_name)
 483                         continue;
 484                 ptr->is_deleted = is_delete;
 485                 error = 0;
 486                 goto out;
 487         }
 488         if (is_delete) {
 489                 error = -ENOENT;
 490                 goto out;
 491         }
 492         new_entry = tomoyo_alloc_element(sizeof(*new_entry));
 493         if (!new_entry)
 494                 goto out;
 495         new_entry->original_name = saved_original_name;
 496         new_entry->aliased_name = saved_aliased_name;
 497         list_add_tail(&new_entry->list, &tomoyo_alias_list);
 498         error = 0;
 499  out:
 500         up_write(&tomoyo_alias_list_lock);
 501         /***** EXCLUSIVE SECTION END *****/
 502         return error;
 503 }
 504
 505 /**
 506  * tomoyo_read_alias_policy - Read "struct tomoyo_alias_entry" list.
 507  *
 508  * @head: Pointer to "struct tomoyo_io_buffer".
 509  *
 510  * Returns true on success, false otherwise.
 511  */
 512 bool tomoyo_read_alias_policy(struct tomoyo_io_buffer *head)
 513 {
 514         struct list_head *pos;
 515         bool done = true;
 516
 517         down_read(&tomoyo_alias_list_lock);
 518         list_for_each_cookie(pos, head->read_var2, &tomoyo_alias_list) {
 519                 struct tomoyo_alias_entry *ptr;
 520
 521                 ptr = list_entry(pos, struct tomoyo_alias_entry, list);
 522                 if (ptr->is_deleted)
 523                         continue;
 524                 if (!tomoyo_io_printf(head, TOMOYO_KEYWORD_ALIAS "%s %s\n",
 525                                       ptr->original_name->name,
 526                                       ptr->aliased_name->name)) {
 527                         done = false;
 528                         break;
 529                 }
 530         }
 531         up_read(&tomoyo_alias_list_lock);
 532         return done;
 533 }
 534
 535 /**
 536  * tomoyo_write_alias_policy - Write "struct tomoyo_alias_entry" list.
 537  *
 538  * @data:      String to parse.
 539  * @is_delete: True if it is a delete request.
 540  *
 541  * Returns 0 on success, negative value otherwise.
 542  */
 543 int tomoyo_write_alias_policy(char *data, const bool is_delete)
 544 {
 545         char *cp = strchr(data, ' ');
 546
 547         if (!cp)
 548                 return -EINVAL;
 549         *cp++ = '\0';
 550         return tomoyo_update_alias_entry(data, cp, is_delete);
 551 }
 552
 553 /* Domain create/delete handler. */
 554
 555 /**
 556  * tomoyo_delete_domain - Delete a domain.
 557  *
 558  * @domainname: The name of domain.
 559  *
 560  * Returns 0.
 561  */
 562 int tomoyo_delete_domain(char *domainname)
 563 {
 564         struct tomoyo_domain_info *domain;
 565         struct tomoyo_path_info name;
 566
 567         name.name = domainname;
 568         tomoyo_fill_path_info(&name);
 569         /***** EXCLUSIVE SECTION START *****/
 570         down_write(&tomoyo_domain_list_lock);
 571         /* Is there an active domain? */
 572         list_for_each_entry(domain, &tomoyo_domain_list, list) {
 573                 /* Never delete tomoyo_kernel_domain */
 574                 if (domain == &tomoyo_kernel_domain)
 575                         continue;
 576                 if (domain->is_deleted ||
 577                     tomoyo_pathcmp(domain->domainname, &name))
 578                         continue;
 579                 domain->is_deleted = true;
 580                 break;
 581         }
 582         up_write(&tomoyo_domain_list_lock);
 583         /***** EXCLUSIVE SECTION END *****/
 584         return 0;
 585 }
 586
 587 /**
 588  * tomoyo_find_or_assign_new_domain - Create a domain.
 589  *
 590  * @domainname: The name of domain.
 591  * @profile:    Profile number to assign if the domain was newly created.
 592  *
 593  * Returns pointer to "struct tomoyo_domain_info" on success, NULL otherwise.
 594  */
 595 struct tomoyo_domain_info *tomoyo_find_or_assign_new_domain(const char *
 596                                                             domainname,
 597                                                             const u8 profile)
 598 {
 599         struct tomoyo_domain_info *domain = NULL;
 600         const struct tomoyo_path_info *saved_domainname;
 601
 602         /***** EXCLUSIVE SECTION START *****/
 603         down_write(&tomoyo_domain_list_lock);
 604         domain = tomoyo_find_domain(domainname);
 605         if (domain)
 606                 goto out;
 607         if (!tomoyo_is_correct_domain(domainname, __func__))
 608                 goto out;
 609         saved_domainname = tomoyo_save_name(domainname);
 610         if (!saved_domainname)
 611                 goto out;
 612         /* Can I reuse memory of deleted domain? */
 613         list_for_each_entry(domain, &tomoyo_domain_list, list) {
 614                 struct task_struct *p;
 615                 struct tomoyo_acl_info *ptr;
 616                 bool flag;
 617                 if (!domain->is_deleted ||
 618                     domain->domainname != saved_domainname)
 619                         continue;
 620                 flag = false;
 621                 /***** CRITICAL SECTION START *****/
 622                 read_lock(&tasklist_lock);
 623                 for_each_process(p) {
 624                         if (tomoyo_real_domain(p) != domain)
 625                                 continue;
 626                         flag = true;
 627                         break;
 628                 }
 629                 read_unlock(&tasklist_lock);
 630                 /***** CRITICAL SECTION END *****/
 631                 if (flag)
 632                         continue;
 633                 list_for_each_entry(ptr, &domain->acl_info_list, list) {
 634                         ptr->type |= TOMOYO_ACL_DELETED;
 635                 }
 636                 tomoyo_set_domain_flag(domain, true, domain->flags);
 637                 domain->profile = profile;
 638                 domain->quota_warned = false;
 639                 mb(); /* Avoid out-of-order execution. */
 640                 domain->is_deleted = false;
 641                 goto out;
 642         }
 643         /* No memory reusable. Create using new memory. */
 644         domain = tomoyo_alloc_element(sizeof(*domain));
 645         if (domain) {
 646                 INIT_LIST_HEAD(&domain->acl_info_list);
 647                 domain->domainname = saved_domainname;
 648                 domain->profile = profile;
 649                 list_add_tail(&domain->list, &tomoyo_domain_list);
 650         }
 651  out:
 652         up_write(&tomoyo_domain_list_lock);
 653         /***** EXCLUSIVE SECTION END *****/
 654         return domain;
 655 }
 656
 657 /**
 658  * tomoyo_find_next_domain - Find a domain.
 659  *
 660  * @bprm:           Pointer to "struct linux_binprm".
 661  * @next_domain:    Pointer to pointer to "struct tomoyo_domain_info".
 662  *
 663  * Returns 0 on success, negative value otherwise.
 664  */
 665 int tomoyo_find_next_domain(struct linux_binprm *bprm,
 666                             struct tomoyo_domain_info **next_domain)
 667 {
 668         /*
 669          * This function assumes that the size of buffer returned by
 670          * tomoyo_realpath() = TOMOYO_MAX_PATHNAME_LEN.
 671          */
 672         struct tomoyo_page_buffer *tmp = tomoyo_alloc(sizeof(*tmp));
 673         struct tomoyo_domain_info *old_domain = tomoyo_domain();
 674         struct tomoyo_domain_info *domain = NULL;
 675         const char *old_domain_name = old_domain->domainname->name;
 676         const char *original_name = bprm->filename;
 677         char *new_domain_name = NULL;
 678         char *real_program_name = NULL;
 679         char *symlink_program_name = NULL;
 680         const u8 mode = tomoyo_check_flags(old_domain, TOMOYO_MAC_FOR_FILE);
 681         const bool is_enforce = (mode == 3);
 682         int retval = -ENOMEM;
 683         struct tomoyo_path_info r; /* real name */
 684         struct tomoyo_path_info s; /* symlink name */
 685         struct tomoyo_path_info l; /* last name */
 686         static bool initialized;
 687
 688         if (!tmp)
 689                 goto out;
 690
 691         if (!initialized) {
 692                 /*
 693                  * Built-in initializers. This is needed because policies are
 694                  * not loaded until starting /sbin/init.
 695                  */
 696                 tomoyo_update_domain_initializer_entry(NULL, "/sbin/hotplug",
 697                                                        false, false);
 698                 tomoyo_update_domain_initializer_entry(NULL, "/sbin/modprobe",
 699                                                        false, false);
 700                 initialized = true;
 701         }
 702
 703         /* Get tomoyo_realpath of program. */
 704         retval = -ENOENT;
 705         /* I hope tomoyo_realpath() won't fail with -ENOMEM. */
 706         real_program_name = tomoyo_realpath(original_name);
 707         if (!real_program_name)
 708                 goto out;
 709         /* Get tomoyo_realpath of symbolic link. */
 710         symlink_program_name = tomoyo_realpath_nofollow(original_name);
 711         if (!symlink_program_name)
 712                 goto out;
 713
 714         r.name = real_program_name;
 715         tomoyo_fill_path_info(&r);
 716         s.name = symlink_program_name;
 717         tomoyo_fill_path_info(&s);
 718         l.name = tomoyo_get_last_name(old_domain);
 719         tomoyo_fill_path_info(&l);
 720
 721         /* Check 'alias' directive. */
 722         if (tomoyo_pathcmp(&r, &s)) {
 723                 struct tomoyo_alias_entry *ptr;
 724                 /* Is this program allowed to be called via symbolic links? */
 725                 down_read(&tomoyo_alias_list_lock);
 726                 list_for_each_entry(ptr, &tomoyo_alias_list, list) {
 727                         if (ptr->is_deleted ||
 728                             tomoyo_pathcmp(&r, ptr->original_name) ||
 729                             tomoyo_pathcmp(&s, ptr->aliased_name))
 730                                 continue;
 731                         memset(real_program_name, 0, TOMOYO_MAX_PATHNAME_LEN);
 732                         strncpy(real_program_name, ptr->aliased_name->name,
 733                                 TOMOYO_MAX_PATHNAME_LEN - 1);
 734                         tomoyo_fill_path_info(&r);
 735                         break;
 736                 }
 737                 up_read(&tomoyo_alias_list_lock);
 738         }
 739
 740         /* Check execute permission. */
 741         retval = tomoyo_check_exec_perm(old_domain, &r, tmp);
 742         if (retval < 0)
 743                 goto out;
 744
 745         new_domain_name = tmp->buffer;
 746         if (tomoyo_is_domain_initializer(old_domain->domainname, &r, &l)) {
 747                 /* Transit to the child of tomoyo_kernel_domain domain. */
 748                 snprintf(new_domain_name, TOMOYO_MAX_PATHNAME_LEN + 1,
 749                          TOMOYO_ROOT_NAME " " "%s", real_program_name);
 750         } else if (old_domain == &tomoyo_kernel_domain &&
 751                    !tomoyo_policy_loaded) {
 752                 /*
 753                  * Needn't to transit from kernel domain before starting
 754                  * /sbin/init. But transit from kernel domain if executing
 755                  * initializers because they might start before /sbin/init.
 756                  */
 757                 domain = old_domain;
 758         } else if (tomoyo_is_domain_keeper(old_domain->domainname, &r, &l)) {
 759                 /* Keep current domain. */
 760                 domain = old_domain;
 761         } else {
 762                 /* Normal domain transition. */
 763                 snprintf(new_domain_name, TOMOYO_MAX_PATHNAME_LEN + 1,
 764                          "%s %s", old_domain_name, real_program_name);
 765         }
 766         if (domain || strlen(new_domain_name) >= TOMOYO_MAX_PATHNAME_LEN)
 767                 goto done;
 768         down_read(&tomoyo_domain_list_lock);
 769         domain = tomoyo_find_domain(new_domain_name);
 770         up_read(&tomoyo_domain_list_lock);
 771         if (domain)
 772                 goto done;
 773         if (is_enforce)
 774                 goto done;
 775         domain = tomoyo_find_or_assign_new_domain(new_domain_name,
 776                                                   old_domain->profile);
 777  done:
 778         if (domain)
 779                 goto out;
 780         printk(KERN_WARNING "TOMOYO-ERROR: Domain '%s' not defined.\n",
 781                new_domain_name);
 782         if (is_enforce)
 783                 retval = -EPERM;
 784         else
 785                 tomoyo_set_domain_flag(old_domain, false,
 786                                        TOMOYO_DOMAIN_FLAGS_TRANSITION_FAILED);
 787  out:
 788         tomoyo_free(real_program_name);
 789         tomoyo_free(symlink_program_name);
 790         *next_domain = domain ? domain : old_domain;
 791         tomoyo_free(tmp);
 792         return retval;
 793 }