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                  * Domain transition preference is allowed for only
 107                  * "file execute" entries.
 108                  */
 109                 if (new_entry->cond->transit &&
 110                     !(new_entry->type == TOMOYO_TYPE_PATH_ACL &&
 111                       container_of(new_entry, struct tomoyo_path_acl, head)
 112                       ->perm == 1 << TOMOYO_TYPE_EXECUTE))
 113                         goto out;
 114         }
 115         if (mutex_lock_interruptible(&tomoyo_policy_lock))
 116                 goto out;
 117         list_for_each_entry_rcu(entry, list, list) {
 118                 if (!tomoyo_same_acl_head(entry, new_entry) ||
 119                     !check_duplicate(entry, new_entry))
 120                         continue;
 121                 if (merge_duplicate)
 122                         entry->is_deleted = merge_duplicate(entry, new_entry,
 123                                                             is_delete);
 124                 else
 125                         entry->is_deleted = is_delete;
 126                 error = 0;
 127                 break;
 128         }
 129         if (error && !is_delete) {
 130                 entry = tomoyo_commit_ok(new_entry, size);
 131                 if (entry) {
 132                         list_add_tail_rcu(&entry->list, list);
 133                         error = 0;
 134                 }
 135         }
 136         mutex_unlock(&tomoyo_policy_lock);
 137 out:
 138         tomoyo_put_condition(new_entry->cond);
 139         return error;
 140 }
 141
 142 /**
 143  * tomoyo_check_acl - Do permission check.
 144  *
 145  * @r:           Pointer to "struct tomoyo_request_info".
 146  * @check_entry: Callback function to check type specific parameters.
 147  *
 148  * Returns 0 on success, negative value otherwise.
 149  *
 150  * Caller holds tomoyo_read_lock().
 151  */
 152 void tomoyo_check_acl(struct tomoyo_request_info *r,
 153                       bool (*check_entry) (struct tomoyo_request_info *,
 154                                            const struct tomoyo_acl_info *))
 155 {
 156         const struct tomoyo_domain_info *domain = r->domain;
 157         struct tomoyo_acl_info *ptr;
 158         bool retried = false;
 159         const struct list_head *list = &domain->acl_info_list;
 160
 161 retry:
 162         list_for_each_entry_rcu(ptr, list, list) {
 163                 if (ptr->is_deleted || ptr->type != r->param_type)
 164                         continue;
 165                 if (!check_entry(r, ptr))
 166                         continue;
 167                 if (!tomoyo_condition(r, ptr->cond))
 168                         continue;
 169                 r->matched_acl = ptr;
 170                 r->granted = true;
 171                 return;
 172         }
 173         if (!retried) {
 174                 retried = true;
 175                 list = &domain->ns->acl_group[domain->group];
 176                 goto retry;
 177         }
 178         r->granted = false;
 179 }
 180
 181 /* The list for "struct tomoyo_domain_info". */
 182 LIST_HEAD(tomoyo_domain_list);
 183
 184 /**
 185  * tomoyo_last_word - Get last component of a domainname.
 186  *
 187  * @name: Domainname to check.
 188  *
 189  * Returns the last word of @domainname.
 190  */
 191 static const char *tomoyo_last_word(const char *name)
 192 {
 193         const char *cp = strrchr(name, ' ');
 194         if (cp)
 195                 return cp + 1;
 196         return name;
 197 }
 198
 199 /**
 200  * tomoyo_same_transition_control - Check for duplicated "struct tomoyo_transition_control" entry.
 201  *
 202  * @a: Pointer to "struct tomoyo_acl_head".
 203  * @b: Pointer to "struct tomoyo_acl_head".
 204  *
 205  * Returns true if @a == @b, false otherwise.
 206  */
 207 static bool tomoyo_same_transition_control(const struct tomoyo_acl_head *a,
 208                                            const struct tomoyo_acl_head *b)
 209 {
 210         const struct tomoyo_transition_control *p1 = container_of(a,
 211                                                                   typeof(*p1),
 212                                                                   head);
 213         const struct tomoyo_transition_control *p2 = container_of(b,
 214                                                                   typeof(*p2),
 215                                                                   head);
 216         return p1->type == p2->type && p1->is_last_name == p2->is_last_name
 217                 && p1->domainname == p2->domainname
 218                 && p1->program == p2->program;
 219 }
 220
 221 /**
 222  * tomoyo_write_transition_control - Write "struct tomoyo_transition_control" list.
 223  *
 224  * @param: Pointer to "struct tomoyo_acl_param".
 225  * @type:  Type of this entry.
 226  *
 227  * Returns 0 on success, negative value otherwise.
 228  */
 229 int tomoyo_write_transition_control(struct tomoyo_acl_param *param,
 230                                     const u8 type)
 231 {
 232         struct tomoyo_transition_control e = { .type = type };
 233         int error = param->is_delete ? -ENOENT : -ENOMEM;
 234         char *program = param->data;
 235         char *domainname = strstr(program, " from ");
 236         if (domainname) {
 237                 *domainname = '\0';
 238                 domainname += 6;
 239         } else if (type == TOMOYO_TRANSITION_CONTROL_NO_KEEP ||
 240                    type == TOMOYO_TRANSITION_CONTROL_KEEP) {
 241                 domainname = program;
 242                 program = NULL;
 243         }
 244         if (program && strcmp(program, "any")) {
 245                 if (!tomoyo_correct_path(program))
 246                         return -EINVAL;
 247                 e.program = tomoyo_get_name(program);
 248                 if (!e.program)
 249                         goto out;
 250         }
 251         if (domainname && strcmp(domainname, "any")) {
 252                 if (!tomoyo_correct_domain(domainname)) {
 253                         if (!tomoyo_correct_path(domainname))
 254                                 goto out;
 255                         e.is_last_name = true;
 256                 }
 257                 e.domainname = tomoyo_get_name(domainname);
 258                 if (!e.domainname)
 259                         goto out;
 260         }
 261         param->list = &param->ns->policy_list[TOMOYO_ID_TRANSITION_CONTROL];
 262         error = tomoyo_update_policy(&e.head, sizeof(e), param,
 263                                      tomoyo_same_transition_control);
 264 out:
 265         tomoyo_put_name(e.domainname);
 266         tomoyo_put_name(e.program);
 267         return error;
 268 }
 269
 270 /**
 271  * tomoyo_scan_transition - Try to find specific domain transition type.
 272  *
 273  * @list:       Pointer to "struct list_head".
 274  * @domainname: The name of current domain.
 275  * @program:    The name of requested program.
 276  * @last_name:  The last component of @domainname.
 277  * @type:       One of values in "enum tomoyo_transition_type".
 278  *
 279  * Returns true if found one, false otherwise.
 280  *
 281  * Caller holds tomoyo_read_lock().
 282  */
 283 static inline bool tomoyo_scan_transition
 284 (const struct list_head *list, const struct tomoyo_path_info *domainname,
 285  const struct tomoyo_path_info *program, const char *last_name,
 286  const enum tomoyo_transition_type type)
 287 {
 288         const struct tomoyo_transition_control *ptr;
 289         list_for_each_entry_rcu(ptr, list, head.list) {
 290                 if (ptr->head.is_deleted || ptr->type != type)
 291                         continue;
 292                 if (ptr->domainname) {
 293                         if (!ptr->is_last_name) {
 294                                 if (ptr->domainname != domainname)
 295                                         continue;
 296                         } else {
 297                                 /*
 298                                  * Use direct strcmp() since this is
 299                                  * unlikely used.
 300                                  */
 301                                 if (strcmp(ptr->domainname->name, last_name))
 302                                         continue;
 303                         }
 304                 }
 305                 if (ptr->program && tomoyo_pathcmp(ptr->program, program))
 306                         continue;
 307                 return true;
 308         }
 309         return false;
 310 }
 311
 312 /**
 313  * tomoyo_transition_type - Get domain transition type.
 314  *
 315  * @ns:         Pointer to "struct tomoyo_policy_namespace".
 316  * @domainname: The name of current domain.
 317  * @program:    The name of requested program.
 318  *
 319  * Returns TOMOYO_TRANSITION_CONTROL_TRANSIT if executing @program causes
 320  * domain transition across namespaces, TOMOYO_TRANSITION_CONTROL_INITIALIZE if
 321  * executing @program reinitializes domain transition within that namespace,
 322  * TOMOYO_TRANSITION_CONTROL_KEEP if executing @program stays at @domainname ,
 323  * others otherwise.
 324  *
 325  * Caller holds tomoyo_read_lock().
 326  */
 327 static enum tomoyo_transition_type tomoyo_transition_type
 328 (const struct tomoyo_policy_namespace *ns,
 329  const struct tomoyo_path_info *domainname,
 330  const struct tomoyo_path_info *program)
 331 {
 332         const char *last_name = tomoyo_last_word(domainname->name);
 333         enum tomoyo_transition_type type = TOMOYO_TRANSITION_CONTROL_NO_RESET;
 334         while (type < TOMOYO_MAX_TRANSITION_TYPE) {
 335                 const struct list_head * const list =
 336                         &ns->policy_list[TOMOYO_ID_TRANSITION_CONTROL];
 337                 if (!tomoyo_scan_transition(list, domainname, program,
 338                                             last_name, type)) {
 339                         type++;
 340                         continue;
 341                 }
 342                 if (type != TOMOYO_TRANSITION_CONTROL_NO_RESET &&
 343                     type != TOMOYO_TRANSITION_CONTROL_NO_INITIALIZE)
 344                         break;
 345                 /*
 346                  * Do not check for reset_domain if no_reset_domain matched.
 347                  * Do not check for initialize_domain if no_initialize_domain
 348                  * matched.
 349                  */
 350                 type++;
 351                 type++;
 352         }
 353         return type;
 354 }
 355
 356 /**
 357  * tomoyo_same_aggregator - Check for duplicated "struct tomoyo_aggregator" entry.
 358  *
 359  * @a: Pointer to "struct tomoyo_acl_head".
 360  * @b: Pointer to "struct tomoyo_acl_head".
 361  *
 362  * Returns true if @a == @b, false otherwise.
 363  */
 364 static bool tomoyo_same_aggregator(const struct tomoyo_acl_head *a,
 365                                    const struct tomoyo_acl_head *b)
 366 {
 367         const struct tomoyo_aggregator *p1 = container_of(a, typeof(*p1),
 368                                                           head);
 369         const struct tomoyo_aggregator *p2 = container_of(b, typeof(*p2),
 370                                                           head);
 371         return p1->original_name == p2->original_name &&
 372                 p1->aggregated_name == p2->aggregated_name;
 373 }
 374
 375 /**
 376  * tomoyo_write_aggregator - Write "struct tomoyo_aggregator" list.
 377  *
 378  * @param: Pointer to "struct tomoyo_acl_param".
 379  *
 380  * Returns 0 on success, negative value otherwise.
 381  *
 382  * Caller holds tomoyo_read_lock().
 383  */
 384 int tomoyo_write_aggregator(struct tomoyo_acl_param *param)
 385 {
 386         struct tomoyo_aggregator e = { };
 387         int error = param->is_delete ? -ENOENT : -ENOMEM;
 388         const char *original_name = tomoyo_read_token(param);
 389         const char *aggregated_name = tomoyo_read_token(param);
 390         if (!tomoyo_correct_word(original_name) ||
 391             !tomoyo_correct_path(aggregated_name))
 392                 return -EINVAL;
 393         e.original_name = tomoyo_get_name(original_name);
 394         e.aggregated_name = tomoyo_get_name(aggregated_name);
 395         if (!e.original_name || !e.aggregated_name ||
 396             e.aggregated_name->is_patterned) /* No patterns allowed. */
 397                 goto out;
 398         param->list = &param->ns->policy_list[TOMOYO_ID_AGGREGATOR];
 399         error = tomoyo_update_policy(&e.head, sizeof(e), param,
 400                                      tomoyo_same_aggregator);
 401 out:
 402         tomoyo_put_name(e.original_name);
 403         tomoyo_put_name(e.aggregated_name);
 404         return error;
 405 }
 406
 407 /**
 408  * tomoyo_find_namespace - Find specified namespace.
 409  *
 410  * @name: Name of namespace to find.
 411  * @len:  Length of @name.
 412  *
 413  * Returns pointer to "struct tomoyo_policy_namespace" if found,
 414  * NULL otherwise.
 415  *
 416  * Caller holds tomoyo_read_lock().
 417  */
 418 static struct tomoyo_policy_namespace *tomoyo_find_namespace
 419 (const char *name, const unsigned int len)
 420 {
 421         struct tomoyo_policy_namespace *ns;
 422         list_for_each_entry(ns, &tomoyo_namespace_list, namespace_list) {
 423                 if (strncmp(name, ns->name, len) ||
 424                     (name[len] && name[len] != ' '))
 425                         continue;
 426                 return ns;
 427         }
 428         return NULL;
 429 }
 430
 431 /**
 432  * tomoyo_assign_namespace - Create a new namespace.
 433  *
 434  * @domainname: Name of namespace to create.
 435  *
 436  * Returns pointer to "struct tomoyo_policy_namespace" on success,
 437  * NULL otherwise.
 438  *
 439  * Caller holds tomoyo_read_lock().
 440  */
 441 struct tomoyo_policy_namespace *tomoyo_assign_namespace(const char *domainname)
 442 {
 443         struct tomoyo_policy_namespace *ptr;
 444         struct tomoyo_policy_namespace *entry;
 445         const char *cp = domainname;
 446         unsigned int len = 0;
 447         while (*cp && *cp++ != ' ')
 448                 len++;
 449         ptr = tomoyo_find_namespace(domainname, len);
 450         if (ptr)
 451                 return ptr;
 452         if (len >= TOMOYO_EXEC_TMPSIZE - 10 || !tomoyo_domain_def(domainname))
 453                 return NULL;
 454         entry = kzalloc(sizeof(*entry) + len + 1, GFP_NOFS);
 455         if (!entry)
 456                 return NULL;
 457         if (mutex_lock_interruptible(&tomoyo_policy_lock))
 458                 goto out;
 459         ptr = tomoyo_find_namespace(domainname, len);
 460         if (!ptr && tomoyo_memory_ok(entry)) {
 461                 char *name = (char *) (entry + 1);
 462                 ptr = entry;
 463                 memmove(name, domainname, len);
 464                 name[len] = '\0';
 465                 entry->name = name;
 466                 tomoyo_init_policy_namespace(entry);
 467                 entry = NULL;
 468         }
 469         mutex_unlock(&tomoyo_policy_lock);
 470 out:
 471         kfree(entry);
 472         return ptr;
 473 }
 474
 475 /**
 476  * tomoyo_namespace_jump - Check for namespace jump.
 477  *
 478  * @domainname: Name of domain.
 479  *
 480  * Returns true if namespace differs, false otherwise.
 481  */
 482 static bool tomoyo_namespace_jump(const char *domainname)
 483 {
 484         const char *namespace = tomoyo_current_namespace()->name;
 485         const int len = strlen(namespace);
 486         return strncmp(domainname, namespace, len) ||
 487                 (domainname[len] && domainname[len] != ' ');
 488 }
 489
 490 /**
 491  * tomoyo_assign_domain - Create a domain or a namespace.
 492  *
 493  * @domainname: The name of domain.
 494  * @transit:    True if transit to domain found or created.
 495  *
 496  * Returns pointer to "struct tomoyo_domain_info" on success, NULL otherwise.
 497  *
 498  * Caller holds tomoyo_read_lock().
 499  */
 500 struct tomoyo_domain_info *tomoyo_assign_domain(const char *domainname,
 501                                                 const bool transit)
 502 {
 503         struct tomoyo_domain_info e = { };
 504         struct tomoyo_domain_info *entry = tomoyo_find_domain(domainname);
 505         bool created = false;
 506         if (entry) {
 507                 if (transit) {
 508                         /*
 509                          * Since namespace is created at runtime, profiles may
 510                          * not be created by the moment the process transits to
 511                          * that domain. Do not perform domain transition if
 512                          * profile for that domain is not yet created.
 513                          */
 514                         if (!entry->ns->profile_ptr[entry->profile])
 515                                 return NULL;
 516                 }
 517                 return entry;
 518         }
 519         /* Requested domain does not exist. */
 520         /* Don't create requested domain if domainname is invalid. */
 521         if (strlen(domainname) >= TOMOYO_EXEC_TMPSIZE - 10 ||
 522             !tomoyo_correct_domain(domainname))
 523                 return NULL;
 524         /*
 525          * Since definition of profiles and acl_groups may differ across
 526          * namespaces, do not inherit "use_profile" and "use_group" settings
 527          * by automatically creating requested domain upon domain transition.
 528          */
 529         if (transit && tomoyo_namespace_jump(domainname))
 530                 return NULL;
 531         e.ns = tomoyo_assign_namespace(domainname);
 532         if (!e.ns)
 533                 return NULL;
 534         /*
 535          * "use_profile" and "use_group" settings for automatically created
 536          * domains are inherited from current domain. These are 0 for manually
 537          * created domains.
 538          */
 539         if (transit) {
 540                 const struct tomoyo_domain_info *domain = tomoyo_domain();
 541                 e.profile = domain->profile;
 542                 e.group = domain->group;
 543         }
 544         e.domainname = tomoyo_get_name(domainname);
 545         if (!e.domainname)
 546                 return NULL;
 547         if (mutex_lock_interruptible(&tomoyo_policy_lock))
 548                 goto out;
 549         entry = tomoyo_find_domain(domainname);
 550         if (!entry) {
 551                 entry = tomoyo_commit_ok(&e, sizeof(e));
 552                 if (entry) {
 553                         INIT_LIST_HEAD(&entry->acl_info_list);
 554                         list_add_tail_rcu(&entry->list, &tomoyo_domain_list);
 555                         created = true;
 556                 }
 557         }
 558         mutex_unlock(&tomoyo_policy_lock);
 559 out:
 560         tomoyo_put_name(e.domainname);
 561         if (entry && transit) {
 562                 if (created) {
 563                         struct tomoyo_request_info r;
 564                         tomoyo_init_request_info(&r, entry,
 565                                                  TOMOYO_MAC_FILE_EXECUTE);
 566                         r.granted = false;
 567                         tomoyo_write_log(&r, "use_profile %u\n",
 568                                          entry->profile);
 569                         tomoyo_write_log(&r, "use_group %u\n", entry->group);
 570                 }
 571         }
 572         return entry;
 573 }
 574
 575 /**
 576  * tomoyo_environ - Check permission for environment variable names.
 577  *
 578  * @ee: Pointer to "struct tomoyo_execve".
 579  *
 580  * Returns 0 on success, negative value otherwise.
 581  */
 582 static int tomoyo_environ(struct tomoyo_execve *ee)
 583 {
 584         struct tomoyo_request_info *r = &ee->r;
 585         struct linux_binprm *bprm = ee->bprm;
 586         /* env_page.data is allocated by tomoyo_dump_page(). */
 587         struct tomoyo_page_dump env_page = { };
 588         char *arg_ptr; /* Size is TOMOYO_EXEC_TMPSIZE bytes */
 589         int arg_len = 0;
 590         unsigned long pos = bprm->p;
 591         int offset = pos % PAGE_SIZE;
 592         int argv_count = bprm->argc;
 593         int envp_count = bprm->envc;
 594         int error = -ENOMEM;
 595
 596         ee->r.type = TOMOYO_MAC_ENVIRON;
 597         ee->r.profile = r->domain->profile;
 598         ee->r.mode = tomoyo_get_mode(r->domain->ns, ee->r.profile,
 599                                      TOMOYO_MAC_ENVIRON);
 600         if (!r->mode || !envp_count)
 601                 return 0;
 602         arg_ptr = kzalloc(TOMOYO_EXEC_TMPSIZE, GFP_NOFS);
 603         if (!arg_ptr)
 604                 goto out;
 605         while (error == -ENOMEM) {
 606                 if (!tomoyo_dump_page(bprm, pos, &env_page))
 607                         goto out;
 608                 pos += PAGE_SIZE - offset;
 609                 /* Read. */
 610                 while (argv_count && offset < PAGE_SIZE) {
 611                         if (!env_page.data[offset++])
 612                                 argv_count--;
 613                 }
 614                 if (argv_count) {
 615                         offset = 0;
 616                         continue;
 617                 }
 618                 while (offset < PAGE_SIZE) {
 619                         const unsigned char c = env_page.data[offset++];
 620
 621                         if (c && arg_len < TOMOYO_EXEC_TMPSIZE - 10) {
 622                                 if (c == '=') {
 623                                         arg_ptr[arg_len++] = '\0';
 624                                 } else if (c == '\\') {
 625                                         arg_ptr[arg_len++] = '\\';
 626                                         arg_ptr[arg_len++] = '\\';
 627                                 } else if (c > ' ' && c < 127) {
 628                                         arg_ptr[arg_len++] = c;
 629                                 } else {
 630                                         arg_ptr[arg_len++] = '\\';
 631                                         arg_ptr[arg_len++] = (c >> 6) + '0';
 632                                         arg_ptr[arg_len++]
 633                                                 = ((c >> 3) & 7) + '0';
 634                                         arg_ptr[arg_len++] = (c & 7) + '0';
 635                                 }
 636                         } else {
 637                                 arg_ptr[arg_len] = '\0';
 638                         }
 639                         if (c)
 640                                 continue;
 641                         if (tomoyo_env_perm(r, arg_ptr)) {
 642                                 error = -EPERM;
 643                                 break;
 644                         }
 645                         if (!--envp_count) {
 646                                 error = 0;
 647                                 break;
 648                         }
 649                         arg_len = 0;
 650                 }
 651                 offset = 0;
 652         }
 653 out:
 654         if (r->mode != TOMOYO_CONFIG_ENFORCING)
 655                 error = 0;
 656         kfree(env_page.data);
 657         kfree(arg_ptr);
 658         return error;
 659 }
 660
 661 /**
 662  * tomoyo_find_next_domain - Find a domain.
 663  *
 664  * @bprm: Pointer to "struct linux_binprm".
 665  *
 666  * Returns 0 on success, negative value otherwise.
 667  *
 668  * Caller holds tomoyo_read_lock().
 669  */
 670 int tomoyo_find_next_domain(struct linux_binprm *bprm)
 671 {
 672         struct tomoyo_domain_info *old_domain = tomoyo_domain();
 673         struct tomoyo_domain_info *domain = NULL;
 674         const char *original_name = bprm->filename;
 675         int retval = -ENOMEM;
 676         bool reject_on_transition_failure = false;
 677         const struct tomoyo_path_info *candidate;
 678         struct tomoyo_path_info exename;
 679         struct tomoyo_execve *ee = kzalloc(sizeof(*ee), GFP_NOFS);
 680
 681         if (!ee)
 682                 return -ENOMEM;
 683         ee->tmp = kzalloc(TOMOYO_EXEC_TMPSIZE, GFP_NOFS);
 684         if (!ee->tmp) {
 685                 kfree(ee);
 686                 return -ENOMEM;
 687         }
 688         /* ee->dump->data is allocated by tomoyo_dump_page(). */
 689         tomoyo_init_request_info(&ee->r, NULL, TOMOYO_MAC_FILE_EXECUTE);
 690         ee->r.ee = ee;
 691         ee->bprm = bprm;
 692         ee->r.obj = &ee->obj;
 693         ee->obj.path1 = bprm->file->f_path;
 694         /* Get symlink's pathname of program. */
 695         retval = -ENOENT;
 696         exename.name = tomoyo_realpath_nofollow(original_name);
 697         if (!exename.name)
 698                 goto out;
 699         tomoyo_fill_path_info(&exename);
 700 retry:
 701         /* Check 'aggregator' directive. */
 702         {
 703                 struct tomoyo_aggregator *ptr;
 704                 struct list_head *list =
 705                         &old_domain->ns->policy_list[TOMOYO_ID_AGGREGATOR];
 706                 /* Check 'aggregator' directive. */
 707                 candidate = &exename;
 708                 list_for_each_entry_rcu(ptr, list, head.list) {
 709                         if (ptr->head.is_deleted ||
 710                             !tomoyo_path_matches_pattern(&exename,
 711                                                          ptr->original_name))
 712                                 continue;
 713                         candidate = ptr->aggregated_name;
 714                         break;
 715                 }
 716         }
 717
 718         /* Check execute permission. */
 719         retval = tomoyo_execute_permission(&ee->r, candidate);
 720         if (retval == TOMOYO_RETRY_REQUEST)
 721                 goto retry;
 722         if (retval < 0)
 723                 goto out;
 724         /*
 725          * To be able to specify domainnames with wildcards, use the
 726          * pathname specified in the policy (which may contain
 727          * wildcard) rather than the pathname passed to execve()
 728          * (which never contains wildcard).
 729          */
 730         if (ee->r.param.path.matched_path)
 731                 candidate = ee->r.param.path.matched_path;
 732
 733         /*
 734          * Check for domain transition preference if "file execute" matched.
 735          * If preference is given, make do_execve() fail if domain transition
 736          * has failed, for domain transition preference should be used with
 737          * destination domain defined.
 738          */
 739         if (ee->transition) {
 740                 const char *domainname = ee->transition->name;
 741                 reject_on_transition_failure = true;
 742                 if (!strcmp(domainname, "keep"))
 743                         goto force_keep_domain;
 744                 if (!strcmp(domainname, "child"))
 745                         goto force_child_domain;
 746                 if (!strcmp(domainname, "reset"))
 747                         goto force_reset_domain;
 748                 if (!strcmp(domainname, "initialize"))
 749                         goto force_initialize_domain;
 750                 if (!strcmp(domainname, "parent")) {
 751                         char *cp;
 752                         strncpy(ee->tmp, old_domain->domainname->name,
 753                                 TOMOYO_EXEC_TMPSIZE - 1);
 754                         cp = strrchr(ee->tmp, ' ');
 755                         if (cp)
 756                                 *cp = '\0';
 757                 } else if (*domainname == '<')
 758                         strncpy(ee->tmp, domainname, TOMOYO_EXEC_TMPSIZE - 1);
 759                 else
 760                         snprintf(ee->tmp, TOMOYO_EXEC_TMPSIZE - 1, "%s %s",
 761                                  old_domain->domainname->name, domainname);
 762                 goto force_jump_domain;
 763         }
 764         /*
 765          * No domain transition preference specified.
 766          * Calculate domain to transit to.
 767          */
 768         switch (tomoyo_transition_type(old_domain->ns, old_domain->domainname,
 769                                        candidate)) {
 770         case TOMOYO_TRANSITION_CONTROL_RESET:
 771 force_reset_domain:
 772                 /* Transit to the root of specified namespace. */
 773                 snprintf(ee->tmp, TOMOYO_EXEC_TMPSIZE - 1, "<%s>",
 774                          candidate->name);
 775                 /*
 776                  * Make do_execve() fail if domain transition across namespaces
 777                  * has failed.
 778                  */
 779                 reject_on_transition_failure = true;
 780                 break;
 781         case TOMOYO_TRANSITION_CONTROL_INITIALIZE:
 782 force_initialize_domain:
 783                 /* Transit to the child of current namespace's root. */
 784                 snprintf(ee->tmp, TOMOYO_EXEC_TMPSIZE - 1, "%s %s",
 785                          old_domain->ns->name, candidate->name);
 786                 break;
 787         case TOMOYO_TRANSITION_CONTROL_KEEP:
 788 force_keep_domain:
 789                 /* Keep current domain. */
 790                 domain = old_domain;
 791                 break;
 792         default:
 793                 if (old_domain == &tomoyo_kernel_domain &&
 794                     !tomoyo_policy_loaded) {
 795                         /*
 796                          * Needn't to transit from kernel domain before
 797                          * starting /sbin/init. But transit from kernel domain
 798                          * if executing initializers because they might start
 799                          * before /sbin/init.
 800                          */
 801                         domain = old_domain;
 802                         break;
 803                 }
 804 force_child_domain:
 805                 /* Normal domain transition. */
 806                 snprintf(ee->tmp, TOMOYO_EXEC_TMPSIZE - 1, "%s %s",
 807                          old_domain->domainname->name, candidate->name);
 808                 break;
 809         }
 810 force_jump_domain:
 811         if (!domain)
 812                 domain = tomoyo_assign_domain(ee->tmp, true);
 813         if (domain)
 814                 retval = 0;
 815         else if (reject_on_transition_failure) {
 816                 printk(KERN_WARNING "ERROR: Domain '%s' not ready.\n",
 817                        ee->tmp);
 818                 retval = -ENOMEM;
 819         } else if (ee->r.mode == TOMOYO_CONFIG_ENFORCING)
 820                 retval = -ENOMEM;
 821         else {
 822                 retval = 0;
 823                 if (!old_domain->flags[TOMOYO_DIF_TRANSITION_FAILED]) {
 824                         old_domain->flags[TOMOYO_DIF_TRANSITION_FAILED] = true;
 825                         ee->r.granted = false;
 826                         tomoyo_write_log(&ee->r, "%s", tomoyo_dif
 827                                          [TOMOYO_DIF_TRANSITION_FAILED]);
 828                         printk(KERN_WARNING
 829                                "ERROR: Domain '%s' not defined.\n", ee->tmp);
 830                 }
 831         }
 832  out:
 833         if (!domain)
 834                 domain = old_domain;
 835         /* Update reference count on "struct tomoyo_domain_info". */
 836         atomic_inc(&domain->users);
 837         bprm->cred->security = domain;
 838         kfree(exename.name);
 839         if (!retval) {
 840                 ee->r.domain = domain;
 841                 retval = tomoyo_environ(ee);
 842         }
 843         kfree(ee->tmp);
 844         kfree(ee->dump.data);
 845         kfree(ee);
 846         return retval;
 847 }
 848
 849 /**
 850  * tomoyo_dump_page - Dump a page to buffer.
 851  *
 852  * @bprm: Pointer to "struct linux_binprm".
 853  * @pos:  Location to dump.
 854  * @dump: Poiner to "struct tomoyo_page_dump".
 855  *
 856  * Returns true on success, false otherwise.
 857  */
 858 bool tomoyo_dump_page(struct linux_binprm *bprm, unsigned long pos,
 859                       struct tomoyo_page_dump *dump)
 860 {
 861         struct page *page;
 862
 863         /* dump->data is released by tomoyo_find_next_domain(). */
 864         if (!dump->data) {
 865                 dump->data = kzalloc(PAGE_SIZE, GFP_NOFS);
 866                 if (!dump->data)
 867                         return false;
 868         }
 869         /* Same with get_arg_page(bprm, pos, 0) in fs/exec.c */
 870 #ifdef CONFIG_MMU
 871         if (get_user_pages(current, bprm->mm, pos, 1, 0, 1, &page, NULL) <= 0)
 872                 return false;
 873 #else
 874         page = bprm->page[pos / PAGE_SIZE];
 875 #endif
 876         if (page != dump->page) {
 877                 const unsigned int offset = pos % PAGE_SIZE;
 878                 /*
 879                  * Maybe kmap()/kunmap() should be used here.
 880                  * But remove_arg_zero() uses kmap_atomic()/kunmap_atomic().
 881                  * So do I.
 882                  */
 883                 char *kaddr = kmap_atomic(page, KM_USER0);
 884
 885                 dump->page = page;
 886                 memcpy(dump->data + offset, kaddr + offset,
 887                        PAGE_SIZE - offset);
 888                 kunmap_atomic(kaddr, KM_USER0);
 889         }
 890         /* Same with put_arg_page(page) in fs/exec.c */
 891 #ifdef CONFIG_MMU
 892         put_page(page);
 893 #endif
 894         return true;
 895 }