security/tomoyo/domain.c

   1 /*
   2  * security/tomoyo/domain.c
   3  *
   4  * Copyright (C) 2005-2011  NTT DATA CORPORATION
   5  */
   6
   7 #include "common.h"
   8 #include <linux/binfmts.h>
   9 #include <linux/slab.h>
  10
  11 /* Variables definitions.*/
  12
  13 /* The initial domain. */
  14 struct tomoyo_domain_info tomoyo_kernel_domain;
  15
  16 /**
  17  * tomoyo_update_policy - Update an entry for exception policy.
  18  *
  19  * @new_entry:       Pointer to "struct tomoyo_acl_info".
  20  * @size:            Size of @new_entry in bytes.
  21  * @param:           Pointer to "struct tomoyo_acl_param".
  22  * @check_duplicate: Callback function to find duplicated entry.
  23  *
  24  * Returns 0 on success, negative value otherwise.
  25  *
  26  * Caller holds tomoyo_read_lock().
  27  */
  28 int tomoyo_update_policy(struct tomoyo_acl_head *new_entry, const int size,
  29                          struct tomoyo_acl_param *param,
  30                          bool (*check_duplicate) (const struct tomoyo_acl_head
  31                                                   *,
  32                                                   const struct tomoyo_acl_head
  33                                                   *))
  34 {
  35         int error = param->is_delete ? -ENOENT : -ENOMEM;
  36         struct tomoyo_acl_head *entry;
  37         struct list_head *list = param->list;
  38
  39         if (mutex_lock_interruptible(&tomoyo_policy_lock))
  40                 return -ENOMEM;
  41         list_for_each_entry_rcu(entry, list, list) {
  42                 if (!check_duplicate(entry, new_entry))
  43                         continue;
  44                 entry->is_deleted = param->is_delete;
  45                 error = 0;
  46                 break;
  47         }
  48         if (error && !param->is_delete) {
  49                 entry = tomoyo_commit_ok(new_entry, size);
  50                 if (entry) {
  51                         list_add_tail_rcu(&entry->list, list);
  52                         error = 0;
  53                 }
  54         }
  55         mutex_unlock(&tomoyo_policy_lock);
  56         return error;
  57 }
  58
  59 /**
  60  * tomoyo_same_acl_head - Check for duplicated "struct tomoyo_acl_info" entry.
  61  *
  62  * @a: Pointer to "struct tomoyo_acl_info".
  63  * @b: Pointer to "struct tomoyo_acl_info".
  64  *
  65  * Returns true if @a == @b, false otherwise.
  66  */
  67 static inline bool tomoyo_same_acl_head(const struct tomoyo_acl_info *a,
  68                                         const struct tomoyo_acl_info *b)
  69 {
  70         return a->type == b->type && a->cond == b->cond;
  71 }
  72
  73 /**
  74  * tomoyo_update_domain - Update an entry for domain policy.
  75  *
  76  * @new_entry:       Pointer to "struct tomoyo_acl_info".
  77  * @size:            Size of @new_entry in bytes.
  78  * @param:           Pointer to "struct tomoyo_acl_param".
  79  * @check_duplicate: Callback function to find duplicated entry.
  80  * @merge_duplicate: Callback function to merge duplicated entry.
  81  *
  82  * Returns 0 on success, negative value otherwise.
  83  *
  84  * Caller holds tomoyo_read_lock().
  85  */
  86 int tomoyo_update_domain(struct tomoyo_acl_info *new_entry, const int size,
  87                          struct tomoyo_acl_param *param,
  88                          bool (*check_duplicate) (const struct tomoyo_acl_info
  89                                                   *,
  90                                                   const struct tomoyo_acl_info
  91                                                   *),
  92                          bool (*merge_duplicate) (struct tomoyo_acl_info *,
  93                                                   struct tomoyo_acl_info *,
  94                                                   const bool))
  95 {
  96         const bool is_delete = param->is_delete;
  97         int error = is_delete ? -ENOENT : -ENOMEM;
  98         struct tomoyo_acl_info *entry;
  99         struct list_head * const list = param->list;
 100
 101         if (param->data[0]) {
 102                 new_entry->cond = tomoyo_get_condition(param);
 103                 if (!new_entry->cond)
 104                         return -EINVAL;
 105         }
 106         if (mutex_lock_interruptible(&tomoyo_policy_lock))
 107                 goto out;
 108         list_for_each_entry_rcu(entry, list, list) {
 109                 if (!tomoyo_same_acl_head(entry, new_entry) ||
 110                     !check_duplicate(entry, new_entry))
 111                         continue;
 112                 if (merge_duplicate)
 113                         entry->is_deleted = merge_duplicate(entry, new_entry,
 114                                                             is_delete);
 115                 else
 116                         entry->is_deleted = is_delete;
 117                 error = 0;
 118                 break;
 119         }
 120         if (error && !is_delete) {
 121                 entry = tomoyo_commit_ok(new_entry, size);
 122                 if (entry) {
 123                         list_add_tail_rcu(&entry->list, list);
 124                         error = 0;
 125                 }
 126         }
 127         mutex_unlock(&tomoyo_policy_lock);
 128 out:
 129         tomoyo_put_condition(new_entry->cond);
 130         return error;
 131 }
 132
 133 /**
 134  * tomoyo_check_acl - Do permission check.
 135  *
 136  * @r:           Pointer to "struct tomoyo_request_info".
 137  * @check_entry: Callback function to check type specific parameters.
 138  *
 139  * Returns 0 on success, negative value otherwise.
 140  *
 141  * Caller holds tomoyo_read_lock().
 142  */
 143 void tomoyo_check_acl(struct tomoyo_request_info *r,
 144                       bool (*check_entry) (struct tomoyo_request_info *,
 145                                            const struct tomoyo_acl_info *))
 146 {
 147         const struct tomoyo_domain_info *domain = r->domain;
 148         struct tomoyo_acl_info *ptr;
 149         bool retried = false;
 150         const struct list_head *list = &domain->acl_info_list;
 151
 152 retry:
 153         list_for_each_entry_rcu(ptr, list, list) {
 154                 if (ptr->is_deleted || ptr->type != r->param_type)
 155                         continue;
 156                 if (!check_entry(r, ptr))
 157                         continue;
 158                 if (!tomoyo_condition(r, ptr->cond))
 159                         continue;
 160                 r->granted = true;
 161                 return;
 162         }
 163         if (!retried) {
 164                 retried = true;
 165                 list = &domain->ns->acl_group[domain->group];
 166                 goto retry;
 167         }
 168         r->granted = false;
 169 }
 170
 171 /* The list for "struct tomoyo_domain_info". */
 172 LIST_HEAD(tomoyo_domain_list);
 173
 174 /**
 175  * tomoyo_last_word - Get last component of a domainname.
 176  *
 177  * @name: Domainname to check.
 178  *
 179  * Returns the last word of @domainname.
 180  */
 181 static const char *tomoyo_last_word(const char *name)
 182 {
 183         const char *cp = strrchr(name, ' ');
 184         if (cp)
 185                 return cp + 1;
 186         return name;
 187 }
 188
 189 /**
 190  * tomoyo_same_transition_control - Check for duplicated "struct tomoyo_transition_control" entry.
 191  *
 192  * @a: Pointer to "struct tomoyo_acl_head".
 193  * @b: Pointer to "struct tomoyo_acl_head".
 194  *
 195  * Returns true if @a == @b, false otherwise.
 196  */
 197 static bool tomoyo_same_transition_control(const struct tomoyo_acl_head *a,
 198                                            const struct tomoyo_acl_head *b)
 199 {
 200         const struct tomoyo_transition_control *p1 = container_of(a,
 201                                                                   typeof(*p1),
 202                                                                   head);
 203         const struct tomoyo_transition_control *p2 = container_of(b,
 204                                                                   typeof(*p2),
 205                                                                   head);
 206         return p1->type == p2->type && p1->is_last_name == p2->is_last_name
 207                 && p1->domainname == p2->domainname
 208                 && p1->program == p2->program;
 209 }
 210
 211 /**
 212  * tomoyo_write_transition_control - Write "struct tomoyo_transition_control" list.
 213  *
 214  * @param: Pointer to "struct tomoyo_acl_param".
 215  * @type:  Type of this entry.
 216  *
 217  * Returns 0 on success, negative value otherwise.
 218  */
 219 int tomoyo_write_transition_control(struct tomoyo_acl_param *param,
 220                                     const u8 type)
 221 {
 222         struct tomoyo_transition_control e = { .type = type };
 223         int error = param->is_delete ? -ENOENT : -ENOMEM;
 224         char *program = param->data;
 225         char *domainname = strstr(program, " from ");
 226         if (domainname) {
 227                 *domainname = '\0';
 228                 domainname += 6;
 229         } else if (type == TOMOYO_TRANSITION_CONTROL_NO_KEEP ||
 230                    type == TOMOYO_TRANSITION_CONTROL_KEEP) {
 231                 domainname = program;
 232                 program = NULL;
 233         }
 234         if (program && strcmp(program, "any")) {
 235                 if (!tomoyo_correct_path(program))
 236                         return -EINVAL;
 237                 e.program = tomoyo_get_name(program);
 238                 if (!e.program)
 239                         goto out;
 240         }
 241         if (domainname && strcmp(domainname, "any")) {
 242                 if (!tomoyo_correct_domain(domainname)) {
 243                         if (!tomoyo_correct_path(domainname))
 244                                 goto out;
 245                         e.is_last_name = true;
 246                 }
 247                 e.domainname = tomoyo_get_name(domainname);
 248                 if (!e.domainname)
 249                         goto out;
 250         }
 251         param->list = &param->ns->policy_list[TOMOYO_ID_TRANSITION_CONTROL];
 252         error = tomoyo_update_policy(&e.head, sizeof(e), param,
 253                                      tomoyo_same_transition_control);
 254 out:
 255         tomoyo_put_name(e.domainname);
 256         tomoyo_put_name(e.program);
 257         return error;
 258 }
 259
 260 /**
 261  * tomoyo_scan_transition - Try to find specific domain transition type.
 262  *
 263  * @list:       Pointer to "struct list_head".
 264  * @domainname: The name of current domain.
 265  * @program:    The name of requested program.
 266  * @last_name:  The last component of @domainname.
 267  * @type:       One of values in "enum tomoyo_transition_type".
 268  *
 269  * Returns true if found one, false otherwise.
 270  *
 271  * Caller holds tomoyo_read_lock().
 272  */
 273 static inline bool tomoyo_scan_transition
 274 (const struct list_head *list, const struct tomoyo_path_info *domainname,
 275  const struct tomoyo_path_info *program, const char *last_name,
 276  const enum tomoyo_transition_type type)
 277 {
 278         const struct tomoyo_transition_control *ptr;
 279         list_for_each_entry_rcu(ptr, list, head.list) {
 280                 if (ptr->head.is_deleted || ptr->type != type)
 281                         continue;
 282                 if (ptr->domainname) {
 283                         if (!ptr->is_last_name) {
 284                                 if (ptr->domainname != domainname)
 285                                         continue;
 286                         } else {
 287                                 /*
 288                                  * Use direct strcmp() since this is
 289                                  * unlikely used.
 290                                  */
 291                                 if (strcmp(ptr->domainname->name, last_name))
 292                                         continue;
 293                         }
 294                 }
 295                 if (ptr->program && tomoyo_pathcmp(ptr->program, program))
 296                         continue;
 297                 return true;
 298         }
 299         return false;
 300 }
 301
 302 /**
 303  * tomoyo_transition_type - Get domain transition type.
 304  *
 305  * @ns:         Pointer to "struct tomoyo_policy_namespace".
 306  * @domainname: The name of current domain.
 307  * @program:    The name of requested program.
 308  *
 309  * Returns TOMOYO_TRANSITION_CONTROL_TRANSIT if executing @program causes
 310  * domain transition across namespaces, TOMOYO_TRANSITION_CONTROL_INITIALIZE if
 311  * executing @program reinitializes domain transition within that namespace,
 312  * TOMOYO_TRANSITION_CONTROL_KEEP if executing @program stays at @domainname ,
 313  * others otherwise.
 314  *
 315  * Caller holds tomoyo_read_lock().
 316  */
 317 static enum tomoyo_transition_type tomoyo_transition_type
 318 (const struct tomoyo_policy_namespace *ns,
 319  const struct tomoyo_path_info *domainname,
 320  const struct tomoyo_path_info *program)
 321 {
 322         const char *last_name = tomoyo_last_word(domainname->name);
 323         enum tomoyo_transition_type type = TOMOYO_TRANSITION_CONTROL_NO_RESET;
 324         while (type < TOMOYO_MAX_TRANSITION_TYPE) {
 325                 const struct list_head * const list =
 326                         &ns->policy_list[TOMOYO_ID_TRANSITION_CONTROL];
 327                 if (!tomoyo_scan_transition(list, domainname, program,
 328                                             last_name, type)) {
 329                         type++;
 330                         continue;
 331                 }
 332                 if (type != TOMOYO_TRANSITION_CONTROL_NO_RESET &&
 333                     type != TOMOYO_TRANSITION_CONTROL_NO_INITIALIZE)
 334                         break;
 335                 /*
 336                  * Do not check for reset_domain if no_reset_domain matched.
 337                  * Do not check for initialize_domain if no_initialize_domain
 338                  * matched.
 339                  */
 340                 type++;
 341                 type++;
 342         }
 343         return type;
 344 }
 345
 346 /**
 347  * tomoyo_same_aggregator - Check for duplicated "struct tomoyo_aggregator" entry.
 348  *
 349  * @a: Pointer to "struct tomoyo_acl_head".
 350  * @b: Pointer to "struct tomoyo_acl_head".
 351  *
 352  * Returns true if @a == @b, false otherwise.
 353  */
 354 static bool tomoyo_same_aggregator(const struct tomoyo_acl_head *a,
 355                                    const struct tomoyo_acl_head *b)
 356 {
 357         const struct tomoyo_aggregator *p1 = container_of(a, typeof(*p1),
 358                                                           head);
 359         const struct tomoyo_aggregator *p2 = container_of(b, typeof(*p2),
 360                                                           head);
 361         return p1->original_name == p2->original_name &&
 362                 p1->aggregated_name == p2->aggregated_name;
 363 }
 364
 365 /**
 366  * tomoyo_write_aggregator - Write "struct tomoyo_aggregator" list.
 367  *
 368  * @param: Pointer to "struct tomoyo_acl_param".
 369  *
 370  * Returns 0 on success, negative value otherwise.
 371  *
 372  * Caller holds tomoyo_read_lock().
 373  */
 374 int tomoyo_write_aggregator(struct tomoyo_acl_param *param)
 375 {
 376         struct tomoyo_aggregator e = { };
 377         int error = param->is_delete ? -ENOENT : -ENOMEM;
 378         const char *original_name = tomoyo_read_token(param);
 379         const char *aggregated_name = tomoyo_read_token(param);
 380         if (!tomoyo_correct_word(original_name) ||
 381             !tomoyo_correct_path(aggregated_name))
 382                 return -EINVAL;
 383         e.original_name = tomoyo_get_name(original_name);
 384         e.aggregated_name = tomoyo_get_name(aggregated_name);
 385         if (!e.original_name || !e.aggregated_name ||
 386             e.aggregated_name->is_patterned) /* No patterns allowed. */
 387                 goto out;
 388         param->list = &param->ns->policy_list[TOMOYO_ID_AGGREGATOR];
 389         error = tomoyo_update_policy(&e.head, sizeof(e), param,
 390                                      tomoyo_same_aggregator);
 391 out:
 392         tomoyo_put_name(e.original_name);
 393         tomoyo_put_name(e.aggregated_name);
 394         return error;
 395 }
 396
 397 /**
 398  * tomoyo_find_namespace - Find specified namespace.
 399  *
 400  * @name: Name of namespace to find.
 401  * @len:  Length of @name.
 402  *
 403  * Returns pointer to "struct tomoyo_policy_namespace" if found,
 404  * NULL otherwise.
 405  *
 406  * Caller holds tomoyo_read_lock().
 407  */
 408 static struct tomoyo_policy_namespace *tomoyo_find_namespace
 409 (const char *name, const unsigned int len)
 410 {
 411         struct tomoyo_policy_namespace *ns;
 412         list_for_each_entry(ns, &tomoyo_namespace_list, namespace_list) {
 413                 if (strncmp(name, ns->name, len) ||
 414                     (name[len] && name[len] != ' '))
 415                         continue;
 416                 return ns;
 417         }
 418         return NULL;
 419 }
 420
 421 /**
 422  * tomoyo_assign_namespace - Create a new namespace.
 423  *
 424  * @domainname: Name of namespace to create.
 425  *
 426  * Returns pointer to "struct tomoyo_policy_namespace" on success,
 427  * NULL otherwise.
 428  *
 429  * Caller holds tomoyo_read_lock().
 430  */
 431 struct tomoyo_policy_namespace *tomoyo_assign_namespace(const char *domainname)
 432 {
 433         struct tomoyo_policy_namespace *ptr;
 434         struct tomoyo_policy_namespace *entry;
 435         const char *cp = domainname;
 436         unsigned int len = 0;
 437         while (*cp && *cp++ != ' ')
 438                 len++;
 439         ptr = tomoyo_find_namespace(domainname, len);
 440         if (ptr)
 441                 return ptr;
 442         if (len >= TOMOYO_EXEC_TMPSIZE - 10 || !tomoyo_domain_def(domainname))
 443                 return NULL;
 444         entry = kzalloc(sizeof(*entry) + len + 1, GFP_NOFS);
 445         if (!entry)
 446                 return NULL;
 447         if (mutex_lock_interruptible(&tomoyo_policy_lock))
 448                 goto out;
 449         ptr = tomoyo_find_namespace(domainname, len);
 450         if (!ptr && tomoyo_memory_ok(entry)) {
 451                 char *name = (char *) (entry + 1);
 452                 ptr = entry;
 453                 memmove(name, domainname, len);
 454                 name[len] = '\0';
 455                 entry->name = name;
 456                 tomoyo_init_policy_namespace(entry);
 457                 entry = NULL;
 458         }
 459         mutex_unlock(&tomoyo_policy_lock);
 460 out:
 461         kfree(entry);
 462         return ptr;
 463 }
 464
 465 /**
 466  * tomoyo_namespace_jump - Check for namespace jump.
 467  *
 468  * @domainname: Name of domain.
 469  *
 470  * Returns true if namespace differs, false otherwise.
 471  */
 472 static bool tomoyo_namespace_jump(const char *domainname)
 473 {
 474         const char *namespace = tomoyo_current_namespace()->name;
 475         const int len = strlen(namespace);
 476         return strncmp(domainname, namespace, len) ||
 477                 (domainname[len] && domainname[len] != ' ');
 478 }
 479
 480 /**
 481  * tomoyo_assign_domain - Create a domain or a namespace.
 482  *
 483  * @domainname: The name of domain.
 484  * @transit:    True if transit to domain found or created.
 485  *
 486  * Returns pointer to "struct tomoyo_domain_info" on success, NULL otherwise.
 487  *
 488  * Caller holds tomoyo_read_lock().
 489  */
 490 struct tomoyo_domain_info *tomoyo_assign_domain(const char *domainname,
 491                                                 const bool transit)
 492 {
 493         struct tomoyo_domain_info e = { };
 494         struct tomoyo_domain_info *entry = tomoyo_find_domain(domainname);
 495         bool created = false;
 496         if (entry) {
 497                 if (transit) {
 498                         /*
 499                          * Since namespace is created at runtime, profiles may
 500                          * not be created by the moment the process transits to
 501                          * that domain. Do not perform domain transition if
 502                          * profile for that domain is not yet created.
 503                          */
 504                         if (!entry->ns->profile_ptr[entry->profile])
 505                                 return NULL;
 506                 }
 507                 return entry;
 508         }
 509         /* Requested domain does not exist. */
 510         /* Don't create requested domain if domainname is invalid. */
 511         if (strlen(domainname) >= TOMOYO_EXEC_TMPSIZE - 10 ||
 512             !tomoyo_correct_domain(domainname))
 513                 return NULL;
 514         /*
 515          * Since definition of profiles and acl_groups may differ across
 516          * namespaces, do not inherit "use_profile" and "use_group" settings
 517          * by automatically creating requested domain upon domain transition.
 518          */
 519         if (transit && tomoyo_namespace_jump(domainname))
 520                 return NULL;
 521         e.ns = tomoyo_assign_namespace(domainname);
 522         if (!e.ns)
 523                 return NULL;
 524         /*
 525          * "use_profile" and "use_group" settings for automatically created
 526          * domains are inherited from current domain. These are 0 for manually
 527          * created domains.
 528          */
 529         if (transit) {
 530                 const struct tomoyo_domain_info *domain = tomoyo_domain();
 531                 e.profile = domain->profile;
 532                 e.group = domain->group;
 533         }
 534         e.domainname = tomoyo_get_name(domainname);
 535         if (!e.domainname)
 536                 return NULL;
 537         if (mutex_lock_interruptible(&tomoyo_policy_lock))
 538                 goto out;
 539         entry = tomoyo_find_domain(domainname);
 540         if (!entry) {
 541                 entry = tomoyo_commit_ok(&e, sizeof(e));
 542                 if (entry) {
 543                         INIT_LIST_HEAD(&entry->acl_info_list);
 544                         list_add_tail_rcu(&entry->list, &tomoyo_domain_list);
 545                         created = true;
 546                 }
 547         }
 548         mutex_unlock(&tomoyo_policy_lock);
 549 out:
 550         tomoyo_put_name(e.domainname);
 551         if (entry && transit) {
 552                 if (created) {
 553                         struct tomoyo_request_info r;
 554                         tomoyo_init_request_info(&r, entry,
 555                                                  TOMOYO_MAC_FILE_EXECUTE);
 556                         r.granted = false;
 557                         tomoyo_write_log(&r, "use_profile %u\n",
 558                                          entry->profile);
 559                         tomoyo_write_log(&r, "use_group %u\n", entry->group);
 560                 }
 561         }
 562         return entry;
 563 }
 564
 565 /**
 566  * tomoyo_environ - Check permission for environment variable names.
 567  *
 568  * @ee: Pointer to "struct tomoyo_execve".
 569  *
 570  * Returns 0 on success, negative value otherwise.
 571  */
 572 static int tomoyo_environ(struct tomoyo_execve *ee)
 573 {
 574         struct tomoyo_request_info *r = &ee->r;
 575         struct linux_binprm *bprm = ee->bprm;
 576         /* env_page.data is allocated by tomoyo_dump_page(). */
 577         struct tomoyo_page_dump env_page = { };
 578         char *arg_ptr; /* Size is TOMOYO_EXEC_TMPSIZE bytes */
 579         int arg_len = 0;
 580         unsigned long pos = bprm->p;
 581         int offset = pos % PAGE_SIZE;
 582         int argv_count = bprm->argc;
 583         int envp_count = bprm->envc;
 584         int error = -ENOMEM;
 585
 586         ee->r.type = TOMOYO_MAC_ENVIRON;
 587         ee->r.profile = r->domain->profile;
 588         ee->r.mode = tomoyo_get_mode(r->domain->ns, ee->r.profile,
 589                                      TOMOYO_MAC_ENVIRON);
 590         if (!r->mode || !envp_count)
 591                 return 0;
 592         arg_ptr = kzalloc(TOMOYO_EXEC_TMPSIZE, GFP_NOFS);
 593         if (!arg_ptr)
 594                 goto out;
 595         while (error == -ENOMEM) {
 596                 if (!tomoyo_dump_page(bprm, pos, &env_page))
 597                         goto out;
 598                 pos += PAGE_SIZE - offset;
 599                 /* Read. */
 600                 while (argv_count && offset < PAGE_SIZE) {
 601                         if (!env_page.data[offset++])
 602                                 argv_count--;
 603                 }
 604                 if (argv_count) {
 605                         offset = 0;
 606                         continue;
 607                 }
 608                 while (offset < PAGE_SIZE) {
 609                         const unsigned char c = env_page.data[offset++];
 610
 611                         if (c && arg_len < TOMOYO_EXEC_TMPSIZE - 10) {
 612                                 if (c == '=') {
 613                                         arg_ptr[arg_len++] = '\0';
 614                                 } else if (c == '\\') {
 615                                         arg_ptr[arg_len++] = '\\';
 616                                         arg_ptr[arg_len++] = '\\';
 617                                 } else if (c > ' ' && c < 127) {
 618                                         arg_ptr[arg_len++] = c;
 619                                 } else {
 620                                         arg_ptr[arg_len++] = '\\';
 621                                         arg_ptr[arg_len++] = (c >> 6) + '0';
 622                                         arg_ptr[arg_len++]
 623                                                 = ((c >> 3) & 7) + '0';
 624                                         arg_ptr[arg_len++] = (c & 7) + '0';
 625                                 }
 626                         } else {
 627                                 arg_ptr[arg_len] = '\0';
 628                         }
 629                         if (c)
 630                                 continue;
 631                         if (tomoyo_env_perm(r, arg_ptr)) {
 632                                 error = -EPERM;
 633                                 break;
 634                         }
 635                         if (!--envp_count) {
 636                                 error = 0;
 637                                 break;
 638                         }
 639                         arg_len = 0;
 640                 }
 641                 offset = 0;
 642         }
 643 out:
 644         if (r->mode != TOMOYO_CONFIG_ENFORCING)
 645                 error = 0;
 646         kfree(env_page.data);
 647         kfree(arg_ptr);
 648         return error;
 649 }
 650
 651 /**
 652  * tomoyo_find_next_domain - Find a domain.
 653  *
 654  * @bprm: Pointer to "struct linux_binprm".
 655  *
 656  * Returns 0 on success, negative value otherwise.
 657  *
 658  * Caller holds tomoyo_read_lock().
 659  */
 660 int tomoyo_find_next_domain(struct linux_binprm *bprm)
 661 {
 662         struct tomoyo_domain_info *old_domain = tomoyo_domain();
 663         struct tomoyo_domain_info *domain = NULL;
 664         const char *original_name = bprm->filename;
 665         int retval = -ENOMEM;
 666         bool need_kfree = false;
 667         bool reject_on_transition_failure = false;
 668         struct tomoyo_path_info rn = { }; /* real name */
 669         struct tomoyo_execve *ee = kzalloc(sizeof(*ee), GFP_NOFS);
 670
 671         if (!ee)
 672                 return -ENOMEM;
 673         ee->tmp = kzalloc(TOMOYO_EXEC_TMPSIZE, GFP_NOFS);
 674         if (!ee->tmp) {
 675                 kfree(ee);
 676                 return -ENOMEM;
 677         }
 678         /* ee->dump->data is allocated by tomoyo_dump_page(). */
 679         tomoyo_init_request_info(&ee->r, NULL, TOMOYO_MAC_FILE_EXECUTE);
 680         ee->r.ee = ee;
 681         ee->bprm = bprm;
 682         ee->r.obj = &ee->obj;
 683         ee->obj.path1 = bprm->file->f_path;
 684  retry:
 685         if (need_kfree) {
 686                 kfree(rn.name);
 687                 need_kfree = false;
 688         }
 689         /* Get symlink's pathname of program. */
 690         retval = -ENOENT;
 691         rn.name = tomoyo_realpath_nofollow(original_name);
 692         if (!rn.name)
 693                 goto out;
 694         tomoyo_fill_path_info(&rn);
 695         need_kfree = true;
 696
 697         /* Check 'aggregator' directive. */
 698         {
 699                 struct tomoyo_aggregator *ptr;
 700                 struct list_head *list =
 701                         &old_domain->ns->policy_list[TOMOYO_ID_AGGREGATOR];
 702                 /* Check 'aggregator' directive. */
 703                 list_for_each_entry_rcu(ptr, list, head.list) {
 704                         if (ptr->head.is_deleted ||
 705                             !tomoyo_path_matches_pattern(&rn,
 706                                                          ptr->original_name))
 707                                 continue;
 708                         kfree(rn.name);
 709                         need_kfree = false;
 710                         /* This is OK because it is read only. */
 711                         rn = *ptr->aggregated_name;
 712                         break;
 713                 }
 714         }
 715
 716         /* Check execute permission. */
 717         retval = tomoyo_path_permission(&ee->r, TOMOYO_TYPE_EXECUTE, &rn);
 718         if (retval == TOMOYO_RETRY_REQUEST)
 719                 goto retry;
 720         if (retval < 0)
 721                 goto out;
 722         /*
 723          * To be able to specify domainnames with wildcards, use the
 724          * pathname specified in the policy (which may contain
 725          * wildcard) rather than the pathname passed to execve()
 726          * (which never contains wildcard).
 727          */
 728         if (ee->r.param.path.matched_path) {
 729                 if (need_kfree)
 730                         kfree(rn.name);
 731                 need_kfree = false;
 732                 /* This is OK because it is read only. */
 733                 rn = *ee->r.param.path.matched_path;
 734         }
 735
 736         /* Calculate domain to transit to. */
 737         switch (tomoyo_transition_type(old_domain->ns, old_domain->domainname,
 738                                        &rn)) {
 739         case TOMOYO_TRANSITION_CONTROL_RESET:
 740                 /* Transit to the root of specified namespace. */
 741                 snprintf(ee->tmp, TOMOYO_EXEC_TMPSIZE - 1, "<%s>", rn.name);
 742                 /*
 743                  * Make do_execve() fail if domain transition across namespaces
 744                  * has failed.
 745                  */
 746                 reject_on_transition_failure = true;
 747                 break;
 748         case TOMOYO_TRANSITION_CONTROL_INITIALIZE:
 749                 /* Transit to the child of current namespace's root. */
 750                 snprintf(ee->tmp, TOMOYO_EXEC_TMPSIZE - 1, "%s %s",
 751                          old_domain->ns->name, rn.name);
 752                 break;
 753         case TOMOYO_TRANSITION_CONTROL_KEEP:
 754                 /* Keep current domain. */
 755                 domain = old_domain;
 756                 break;
 757         default:
 758                 if (old_domain == &tomoyo_kernel_domain &&
 759                     !tomoyo_policy_loaded) {
 760                         /*
 761                          * Needn't to transit from kernel domain before
 762                          * starting /sbin/init. But transit from kernel domain
 763                          * if executing initializers because they might start
 764                          * before /sbin/init.
 765                          */
 766                         domain = old_domain;
 767                 } else {
 768                         /* Normal domain transition. */
 769                         snprintf(ee->tmp, TOMOYO_EXEC_TMPSIZE - 1, "%s %s",
 770                                  old_domain->domainname->name, rn.name);
 771                 }
 772                 break;
 773         }
 774         if (!domain)
 775                 domain = tomoyo_assign_domain(ee->tmp, true);
 776         if (domain)
 777                 retval = 0;
 778         else if (reject_on_transition_failure) {
 779                 printk(KERN_WARNING "ERROR: Domain '%s' not ready.\n",
 780                        ee->tmp);
 781                 retval = -ENOMEM;
 782         } else if (ee->r.mode == TOMOYO_CONFIG_ENFORCING)
 783                 retval = -ENOMEM;
 784         else {
 785                 retval = 0;
 786                 if (!old_domain->flags[TOMOYO_DIF_TRANSITION_FAILED]) {
 787                         old_domain->flags[TOMOYO_DIF_TRANSITION_FAILED] = true;
 788                         ee->r.granted = false;
 789                         tomoyo_write_log(&ee->r, "%s", tomoyo_dif
 790                                          [TOMOYO_DIF_TRANSITION_FAILED]);
 791                         printk(KERN_WARNING
 792                                "ERROR: Domain '%s' not defined.\n", ee->tmp);
 793                 }
 794         }
 795  out:
 796         if (!domain)
 797                 domain = old_domain;
 798         /* Update reference count on "struct tomoyo_domain_info". */
 799         atomic_inc(&domain->users);
 800         bprm->cred->security = domain;
 801         if (need_kfree)
 802                 kfree(rn.name);
 803         if (!retval) {
 804                 ee->r.domain = domain;
 805                 retval = tomoyo_environ(ee);
 806         }
 807         kfree(ee->tmp);
 808         kfree(ee->dump.data);
 809         kfree(ee);
 810         return retval;
 811 }
 812
 813 /**
 814  * tomoyo_dump_page - Dump a page to buffer.
 815  *
 816  * @bprm: Pointer to "struct linux_binprm".
 817  * @pos:  Location to dump.
 818  * @dump: Poiner to "struct tomoyo_page_dump".
 819  *
 820  * Returns true on success, false otherwise.
 821  */
 822 bool tomoyo_dump_page(struct linux_binprm *bprm, unsigned long pos,
 823                       struct tomoyo_page_dump *dump)
 824 {
 825         struct page *page;
 826
 827         /* dump->data is released by tomoyo_find_next_domain(). */
 828         if (!dump->data) {
 829                 dump->data = kzalloc(PAGE_SIZE, GFP_NOFS);
 830                 if (!dump->data)
 831                         return false;
 832         }
 833         /* Same with get_arg_page(bprm, pos, 0) in fs/exec.c */
 834 #ifdef CONFIG_MMU
 835         if (get_user_pages(current, bprm->mm, pos, 1, 0, 1, &page, NULL) <= 0)
 836                 return false;
 837 #else
 838         page = bprm->page[pos / PAGE_SIZE];
 839 #endif
 840         if (page != dump->page) {
 841                 const unsigned int offset = pos % PAGE_SIZE;
 842                 /*
 843                  * Maybe kmap()/kunmap() should be used here.
 844                  * But remove_arg_zero() uses kmap_atomic()/kunmap_atomic().
 845                  * So do I.
 846                  */
 847                 char *kaddr = kmap_atomic(page, KM_USER0);
 848
 849                 dump->page = page;
 850                 memcpy(dump->data + offset, kaddr + offset,
 851                        PAGE_SIZE - offset);
 852                 kunmap_atomic(kaddr, KM_USER0);
 853         }
 854         /* Same with put_arg_page(page) in fs/exec.c */
 855 #ifdef CONFIG_MMU
 856         put_page(page);
 857 #endif
 858         return true;
 859 }