security/tomoyo/domain.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * security/tomoyo/domain.c
   4  *
   5  * Copyright (C) 2005-2011  NTT DATA CORPORATION
   6  */
   7
   8 #include "common.h"
   9
  10 #include <linux/binfmts.h>
  11 #include <linux/slab.h>
  12 #include <linux/rculist.h>
  13
  14 /* Variables definitions.*/
  15
  16 /* The initial domain. */
  17 struct tomoyo_domain_info tomoyo_kernel_domain;
  18
  19 /**
  20  * tomoyo_update_policy - Update an entry for exception policy.
  21  *
  22  * @new_entry:       Pointer to "struct tomoyo_acl_info".
  23  * @size:            Size of @new_entry in bytes.
  24  * @param:           Pointer to "struct tomoyo_acl_param".
  25  * @check_duplicate: Callback function to find duplicated entry.
  26  *
  27  * Returns 0 on success, negative value otherwise.
  28  *
  29  * Caller holds tomoyo_read_lock().
  30  */
  31 int tomoyo_update_policy(struct tomoyo_acl_head *new_entry, const int size,
  32                          struct tomoyo_acl_param *param,
  33                          bool (*check_duplicate)(const struct tomoyo_acl_head
  34                                                  *,
  35                                                  const struct tomoyo_acl_head
  36                                                  *))
  37 {
  38         int error = param->is_delete ? -ENOENT : -ENOMEM;
  39         struct tomoyo_acl_head *entry;
  40         struct list_head *list = param->list;
  41
  42         if (mutex_lock_interruptible(&tomoyo_policy_lock))
  43                 return -ENOMEM;
  44         list_for_each_entry_rcu(entry, list, list) {
  45                 if (entry->is_deleted == TOMOYO_GC_IN_PROGRESS)
  46                         continue;
  47                 if (!check_duplicate(entry, new_entry))
  48                         continue;
  49                 entry->is_deleted = param->is_delete;
  50                 error = 0;
  51                 break;
  52         }
  53         if (error && !param->is_delete) {
  54                 entry = tomoyo_commit_ok(new_entry, size);
  55                 if (entry) {
  56                         list_add_tail_rcu(&entry->list, list);
  57                         error = 0;
  58                 }
  59         }
  60         mutex_unlock(&tomoyo_policy_lock);
  61         return error;
  62 }
  63
  64 /**
  65  * tomoyo_same_acl_head - Check for duplicated "struct tomoyo_acl_info" entry.
  66  *
  67  * @a: Pointer to "struct tomoyo_acl_info".
  68  * @b: Pointer to "struct tomoyo_acl_info".
  69  *
  70  * Returns true if @a == @b, false otherwise.
  71  */
  72 static inline bool tomoyo_same_acl_head(const struct tomoyo_acl_info *a,
  73                                         const struct tomoyo_acl_info *b)
  74 {
  75         return a->type == b->type && a->cond == b->cond;
  76 }
  77
  78 /**
  79  * tomoyo_update_domain - Update an entry for domain policy.
  80  *
  81  * @new_entry:       Pointer to "struct tomoyo_acl_info".
  82  * @size:            Size of @new_entry in bytes.
  83  * @param:           Pointer to "struct tomoyo_acl_param".
  84  * @check_duplicate: Callback function to find duplicated entry.
  85  * @merge_duplicate: Callback function to merge duplicated entry.
  86  *
  87  * Returns 0 on success, negative value otherwise.
  88  *
  89  * Caller holds tomoyo_read_lock().
  90  */
  91 int tomoyo_update_domain(struct tomoyo_acl_info *new_entry, const int size,
  92                          struct tomoyo_acl_param *param,
  93                          bool (*check_duplicate)(const struct tomoyo_acl_info
  94                                                  *,
  95                                                  const struct tomoyo_acl_info
  96                                                  *),
  97                          bool (*merge_duplicate)(struct tomoyo_acl_info *,
  98                                                  struct tomoyo_acl_info *,
  99                                                  const bool))
 100 {
 101         const bool is_delete = param->is_delete;
 102         int error = is_delete ? -ENOENT : -ENOMEM;
 103         struct tomoyo_acl_info *entry;
 104         struct list_head * const list = param->list;
 105
 106         if (param->data[0]) {
 107                 new_entry->cond = tomoyo_get_condition(param);
 108                 if (!new_entry->cond)
 109                         return -EINVAL;
 110                 /*
 111                  * Domain transition preference is allowed for only
 112                  * "file execute" entries.
 113                  */
 114                 if (new_entry->cond->transit &&
 115                     !(new_entry->type == TOMOYO_TYPE_PATH_ACL &&
 116                       container_of(new_entry, struct tomoyo_path_acl, head)
 117                       ->perm == 1 << TOMOYO_TYPE_EXECUTE))
 118                         goto out;
 119         }
 120         if (mutex_lock_interruptible(&tomoyo_policy_lock))
 121                 goto out;
 122         list_for_each_entry_rcu(entry, list, list) {
 123                 if (entry->is_deleted == TOMOYO_GC_IN_PROGRESS)
 124                         continue;
 125                 if (!tomoyo_same_acl_head(entry, new_entry) ||
 126                     !check_duplicate(entry, new_entry))
 127                         continue;
 128                 if (merge_duplicate)
 129                         entry->is_deleted = merge_duplicate(entry, new_entry,
 130                                                             is_delete);
 131                 else
 132                         entry->is_deleted = is_delete;
 133                 error = 0;
 134                 break;
 135         }
 136         if (error && !is_delete) {
 137                 entry = tomoyo_commit_ok(new_entry, size);
 138                 if (entry) {
 139                         list_add_tail_rcu(&entry->list, list);
 140                         error = 0;
 141                 }
 142         }
 143         mutex_unlock(&tomoyo_policy_lock);
 144 out:
 145         tomoyo_put_condition(new_entry->cond);
 146         return error;
 147 }
 148
 149 /**
 150  * tomoyo_check_acl - Do permission check.
 151  *
 152  * @r:           Pointer to "struct tomoyo_request_info".
 153  * @check_entry: Callback function to check type specific parameters.
 154  *
 155  * Returns 0 on success, negative value otherwise.
 156  *
 157  * Caller holds tomoyo_read_lock().
 158  */
 159 void tomoyo_check_acl(struct tomoyo_request_info *r,
 160                       bool (*check_entry)(struct tomoyo_request_info *,
 161                                           const struct tomoyo_acl_info *))
 162 {
 163         const struct tomoyo_domain_info *domain = r->domain;
 164         struct tomoyo_acl_info *ptr;
 165         const struct list_head *list = &domain->acl_info_list;
 166         u16 i = 0;
 167
 168 retry:
 169         list_for_each_entry_rcu(ptr, list, list) {
 170                 if (ptr->is_deleted || ptr->type != r->param_type)
 171                         continue;
 172                 if (!check_entry(r, ptr))
 173                         continue;
 174                 if (!tomoyo_condition(r, ptr->cond))
 175                         continue;
 176                 r->matched_acl = ptr;
 177                 r->granted = true;
 178                 return;
 179         }
 180         for (; i < TOMOYO_MAX_ACL_GROUPS; i++) {
 181                 if (!test_bit(i, domain->group))
 182                         continue;
 183                 list = &domain->ns->acl_group[i++];
 184                 goto retry;
 185         }
 186         r->granted = false;
 187 }
 188
 189 /* The list for "struct tomoyo_domain_info". */
 190 LIST_HEAD(tomoyo_domain_list);
 191
 192 /**
 193  * tomoyo_last_word - Get last component of a domainname.
 194  *
 195  * @name: Domainname to check.
 196  *
 197  * Returns the last word of @domainname.
 198  */
 199 static const char *tomoyo_last_word(const char *name)
 200 {
 201         const char *cp = strrchr(name, ' ');
 202
 203         if (cp)
 204                 return cp + 1;
 205         return name;
 206 }
 207
 208 /**
 209  * tomoyo_same_transition_control - Check for duplicated "struct tomoyo_transition_control" entry.
 210  *
 211  * @a: Pointer to "struct tomoyo_acl_head".
 212  * @b: Pointer to "struct tomoyo_acl_head".
 213  *
 214  * Returns true if @a == @b, false otherwise.
 215  */
 216 static bool tomoyo_same_transition_control(const struct tomoyo_acl_head *a,
 217                                            const struct tomoyo_acl_head *b)
 218 {
 219         const struct tomoyo_transition_control *p1 = container_of(a,
 220                                                                   typeof(*p1),
 221                                                                   head);
 222         const struct tomoyo_transition_control *p2 = container_of(b,
 223                                                                   typeof(*p2),
 224                                                                   head);
 225
 226         return p1->type == p2->type && p1->is_last_name == p2->is_last_name
 227                 && p1->domainname == p2->domainname
 228                 && p1->program == p2->program;
 229 }
 230
 231 /**
 232  * tomoyo_write_transition_control - Write "struct tomoyo_transition_control" list.
 233  *
 234  * @param: Pointer to "struct tomoyo_acl_param".
 235  * @type:  Type of this entry.
 236  *
 237  * Returns 0 on success, negative value otherwise.
 238  */
 239 int tomoyo_write_transition_control(struct tomoyo_acl_param *param,
 240                                     const u8 type)
 241 {
 242         struct tomoyo_transition_control e = { .type = type };
 243         int error = param->is_delete ? -ENOENT : -ENOMEM;
 244         char *program = param->data;
 245         char *domainname = strstr(program, " from ");
 246
 247         if (domainname) {
 248                 *domainname = '\0';
 249                 domainname += 6;
 250         } else if (type == TOMOYO_TRANSITION_CONTROL_NO_KEEP ||
 251                    type == TOMOYO_TRANSITION_CONTROL_KEEP) {
 252                 domainname = program;
 253                 program = NULL;
 254         }
 255         if (program && strcmp(program, "any")) {
 256                 if (!tomoyo_correct_path(program))
 257                         return -EINVAL;
 258                 e.program = tomoyo_get_name(program);
 259                 if (!e.program)
 260                         goto out;
 261         }
 262         if (domainname && strcmp(domainname, "any")) {
 263                 if (!tomoyo_correct_domain(domainname)) {
 264                         if (!tomoyo_correct_path(domainname))
 265                                 goto out;
 266                         e.is_last_name = true;
 267                 }
 268                 e.domainname = tomoyo_get_name(domainname);
 269                 if (!e.domainname)
 270                         goto out;
 271         }
 272         param->list = &param->ns->policy_list[TOMOYO_ID_TRANSITION_CONTROL];
 273         error = tomoyo_update_policy(&e.head, sizeof(e), param,
 274                                      tomoyo_same_transition_control);
 275 out:
 276         tomoyo_put_name(e.domainname);
 277         tomoyo_put_name(e.program);
 278         return error;
 279 }
 280
 281 /**
 282  * tomoyo_scan_transition - Try to find specific domain transition type.
 283  *
 284  * @list:       Pointer to "struct list_head".
 285  * @domainname: The name of current domain.
 286  * @program:    The name of requested program.
 287  * @last_name:  The last component of @domainname.
 288  * @type:       One of values in "enum tomoyo_transition_type".
 289  *
 290  * Returns true if found one, false otherwise.
 291  *
 292  * Caller holds tomoyo_read_lock().
 293  */
 294 static inline bool tomoyo_scan_transition
 295 (const struct list_head *list, const struct tomoyo_path_info *domainname,
 296  const struct tomoyo_path_info *program, const char *last_name,
 297  const enum tomoyo_transition_type type)
 298 {
 299         const struct tomoyo_transition_control *ptr;
 300
 301         list_for_each_entry_rcu(ptr, list, head.list) {
 302                 if (ptr->head.is_deleted || ptr->type != type)
 303                         continue;
 304                 if (ptr->domainname) {
 305                         if (!ptr->is_last_name) {
 306                                 if (ptr->domainname != domainname)
 307                                         continue;
 308                         } else {
 309                                 /*
 310                                  * Use direct strcmp() since this is
 311                                  * unlikely used.
 312                                  */
 313                                 if (strcmp(ptr->domainname->name, last_name))
 314                                         continue;
 315                         }
 316                 }
 317                 if (ptr->program && tomoyo_pathcmp(ptr->program, program))
 318                         continue;
 319                 return true;
 320         }
 321         return false;
 322 }
 323
 324 /**
 325  * tomoyo_transition_type - Get domain transition type.
 326  *
 327  * @ns:         Pointer to "struct tomoyo_policy_namespace".
 328  * @domainname: The name of current domain.
 329  * @program:    The name of requested program.
 330  *
 331  * Returns TOMOYO_TRANSITION_CONTROL_TRANSIT if executing @program causes
 332  * domain transition across namespaces, TOMOYO_TRANSITION_CONTROL_INITIALIZE if
 333  * executing @program reinitializes domain transition within that namespace,
 334  * TOMOYO_TRANSITION_CONTROL_KEEP if executing @program stays at @domainname ,
 335  * others otherwise.
 336  *
 337  * Caller holds tomoyo_read_lock().
 338  */
 339 static enum tomoyo_transition_type tomoyo_transition_type
 340 (const struct tomoyo_policy_namespace *ns,
 341  const struct tomoyo_path_info *domainname,
 342  const struct tomoyo_path_info *program)
 343 {
 344         const char *last_name = tomoyo_last_word(domainname->name);
 345         enum tomoyo_transition_type type = TOMOYO_TRANSITION_CONTROL_NO_RESET;
 346
 347         while (type < TOMOYO_MAX_TRANSITION_TYPE) {
 348                 const struct list_head * const list =
 349                         &ns->policy_list[TOMOYO_ID_TRANSITION_CONTROL];
 350
 351                 if (!tomoyo_scan_transition(list, domainname, program,
 352                                             last_name, type)) {
 353                         type++;
 354                         continue;
 355                 }
 356                 if (type != TOMOYO_TRANSITION_CONTROL_NO_RESET &&
 357                     type != TOMOYO_TRANSITION_CONTROL_NO_INITIALIZE)
 358                         break;
 359                 /*
 360                  * Do not check for reset_domain if no_reset_domain matched.
 361                  * Do not check for initialize_domain if no_initialize_domain
 362                  * matched.
 363                  */
 364                 type++;
 365                 type++;
 366         }
 367         return type;
 368 }
 369
 370 /**
 371  * tomoyo_same_aggregator - Check for duplicated "struct tomoyo_aggregator" entry.
 372  *
 373  * @a: Pointer to "struct tomoyo_acl_head".
 374  * @b: Pointer to "struct tomoyo_acl_head".
 375  *
 376  * Returns true if @a == @b, false otherwise.
 377  */
 378 static bool tomoyo_same_aggregator(const struct tomoyo_acl_head *a,
 379                                    const struct tomoyo_acl_head *b)
 380 {
 381         const struct tomoyo_aggregator *p1 = container_of(a, typeof(*p1),
 382                                                           head);
 383         const struct tomoyo_aggregator *p2 = container_of(b, typeof(*p2),
 384                                                           head);
 385
 386         return p1->original_name == p2->original_name &&
 387                 p1->aggregated_name == p2->aggregated_name;
 388 }
 389
 390 /**
 391  * tomoyo_write_aggregator - Write "struct tomoyo_aggregator" list.
 392  *
 393  * @param: Pointer to "struct tomoyo_acl_param".
 394  *
 395  * Returns 0 on success, negative value otherwise.
 396  *
 397  * Caller holds tomoyo_read_lock().
 398  */
 399 int tomoyo_write_aggregator(struct tomoyo_acl_param *param)
 400 {
 401         struct tomoyo_aggregator e = { };
 402         int error = param->is_delete ? -ENOENT : -ENOMEM;
 403         const char *original_name = tomoyo_read_token(param);
 404         const char *aggregated_name = tomoyo_read_token(param);
 405
 406         if (!tomoyo_correct_word(original_name) ||
 407             !tomoyo_correct_path(aggregated_name))
 408                 return -EINVAL;
 409         e.original_name = tomoyo_get_name(original_name);
 410         e.aggregated_name = tomoyo_get_name(aggregated_name);
 411         if (!e.original_name || !e.aggregated_name ||
 412             e.aggregated_name->is_patterned) /* No patterns allowed. */
 413                 goto out;
 414         param->list = &param->ns->policy_list[TOMOYO_ID_AGGREGATOR];
 415         error = tomoyo_update_policy(&e.head, sizeof(e), param,
 416                                      tomoyo_same_aggregator);
 417 out:
 418         tomoyo_put_name(e.original_name);
 419         tomoyo_put_name(e.aggregated_name);
 420         return error;
 421 }
 422
 423 /**
 424  * tomoyo_find_namespace - Find specified namespace.
 425  *
 426  * @name: Name of namespace to find.
 427  * @len:  Length of @name.
 428  *
 429  * Returns pointer to "struct tomoyo_policy_namespace" if found,
 430  * NULL otherwise.
 431  *
 432  * Caller holds tomoyo_read_lock().
 433  */
 434 static struct tomoyo_policy_namespace *tomoyo_find_namespace
 435 (const char *name, const unsigned int len)
 436 {
 437         struct tomoyo_policy_namespace *ns;
 438
 439         list_for_each_entry(ns, &tomoyo_namespace_list, namespace_list) {
 440                 if (strncmp(name, ns->name, len) ||
 441                     (name[len] && name[len] != ' '))
 442                         continue;
 443                 return ns;
 444         }
 445         return NULL;
 446 }
 447
 448 /**
 449  * tomoyo_assign_namespace - Create a new namespace.
 450  *
 451  * @domainname: Name of namespace to create.
 452  *
 453  * Returns pointer to "struct tomoyo_policy_namespace" on success,
 454  * NULL otherwise.
 455  *
 456  * Caller holds tomoyo_read_lock().
 457  */
 458 struct tomoyo_policy_namespace *tomoyo_assign_namespace(const char *domainname)
 459 {
 460         struct tomoyo_policy_namespace *ptr;
 461         struct tomoyo_policy_namespace *entry;
 462         const char *cp = domainname;
 463         unsigned int len = 0;
 464
 465         while (*cp && *cp++ != ' ')
 466                 len++;
 467         ptr = tomoyo_find_namespace(domainname, len);
 468         if (ptr)
 469                 return ptr;
 470         if (len >= TOMOYO_EXEC_TMPSIZE - 10 || !tomoyo_domain_def(domainname))
 471                 return NULL;
 472         entry = kzalloc(sizeof(*entry) + len + 1, GFP_NOFS);
 473         if (!entry)
 474                 return NULL;
 475         if (mutex_lock_interruptible(&tomoyo_policy_lock))
 476                 goto out;
 477         ptr = tomoyo_find_namespace(domainname, len);
 478         if (!ptr && tomoyo_memory_ok(entry)) {
 479                 char *name = (char *) (entry + 1);
 480
 481                 ptr = entry;
 482                 memmove(name, domainname, len);
 483                 name[len] = '\0';
 484                 entry->name = name;
 485                 tomoyo_init_policy_namespace(entry);
 486                 entry = NULL;
 487         }
 488         mutex_unlock(&tomoyo_policy_lock);
 489 out:
 490         kfree(entry);
 491         return ptr;
 492 }
 493
 494 /**
 495  * tomoyo_namespace_jump - Check for namespace jump.
 496  *
 497  * @domainname: Name of domain.
 498  *
 499  * Returns true if namespace differs, false otherwise.
 500  */
 501 static bool tomoyo_namespace_jump(const char *domainname)
 502 {
 503         const char *namespace = tomoyo_current_namespace()->name;
 504         const int len = strlen(namespace);
 505
 506         return strncmp(domainname, namespace, len) ||
 507                 (domainname[len] && domainname[len] != ' ');
 508 }
 509
 510 /**
 511  * tomoyo_assign_domain - Create a domain or a namespace.
 512  *
 513  * @domainname: The name of domain.
 514  * @transit:    True if transit to domain found or created.
 515  *
 516  * Returns pointer to "struct tomoyo_domain_info" on success, NULL otherwise.
 517  *
 518  * Caller holds tomoyo_read_lock().
 519  */
 520 struct tomoyo_domain_info *tomoyo_assign_domain(const char *domainname,
 521                                                 const bool transit)
 522 {
 523         struct tomoyo_domain_info e = { };
 524         struct tomoyo_domain_info *entry = tomoyo_find_domain(domainname);
 525         bool created = false;
 526
 527         if (entry) {
 528                 if (transit) {
 529                         /*
 530                          * Since namespace is created at runtime, profiles may
 531                          * not be created by the moment the process transits to
 532                          * that domain. Do not perform domain transition if
 533                          * profile for that domain is not yet created.
 534                          */
 535                         if (tomoyo_policy_loaded &&
 536                             !entry->ns->profile_ptr[entry->profile])
 537                                 return NULL;
 538                 }
 539                 return entry;
 540         }
 541         /* Requested domain does not exist. */
 542         /* Don't create requested domain if domainname is invalid. */
 543         if (strlen(domainname) >= TOMOYO_EXEC_TMPSIZE - 10 ||
 544             !tomoyo_correct_domain(domainname))
 545                 return NULL;
 546         /*
 547          * Since definition of profiles and acl_groups may differ across
 548          * namespaces, do not inherit "use_profile" and "use_group" settings
 549          * by automatically creating requested domain upon domain transition.
 550          */
 551         if (transit && tomoyo_namespace_jump(domainname))
 552                 return NULL;
 553         e.ns = tomoyo_assign_namespace(domainname);
 554         if (!e.ns)
 555                 return NULL;
 556         /*
 557          * "use_profile" and "use_group" settings for automatically created
 558          * domains are inherited from current domain. These are 0 for manually
 559          * created domains.
 560          */
 561         if (transit) {
 562                 const struct tomoyo_domain_info *domain = tomoyo_domain();
 563
 564                 e.profile = domain->profile;
 565                 memcpy(e.group, domain->group, sizeof(e.group));
 566         }
 567         e.domainname = tomoyo_get_name(domainname);
 568         if (!e.domainname)
 569                 return NULL;
 570         if (mutex_lock_interruptible(&tomoyo_policy_lock))
 571                 goto out;
 572         entry = tomoyo_find_domain(domainname);
 573         if (!entry) {
 574                 entry = tomoyo_commit_ok(&e, sizeof(e));
 575                 if (entry) {
 576                         INIT_LIST_HEAD(&entry->acl_info_list);
 577                         list_add_tail_rcu(&entry->list, &tomoyo_domain_list);
 578                         created = true;
 579                 }
 580         }
 581         mutex_unlock(&tomoyo_policy_lock);
 582 out:
 583         tomoyo_put_name(e.domainname);
 584         if (entry && transit) {
 585                 if (created) {
 586                         struct tomoyo_request_info r;
 587                         int i;
 588
 589                         tomoyo_init_request_info(&r, entry,
 590                                                  TOMOYO_MAC_FILE_EXECUTE);
 591                         r.granted = false;
 592                         tomoyo_write_log(&r, "use_profile %u\n",
 593                                          entry->profile);
 594                         for (i = 0; i < TOMOYO_MAX_ACL_GROUPS; i++)
 595                                 if (test_bit(i, entry->group))
 596                                         tomoyo_write_log(&r, "use_group %u\n",
 597                                                          i);
 598                         tomoyo_update_stat(TOMOYO_STAT_POLICY_UPDATES);
 599                 }
 600         }
 601         return entry;
 602 }
 603
 604 /**
 605  * tomoyo_environ - Check permission for environment variable names.
 606  *
 607  * @ee: Pointer to "struct tomoyo_execve".
 608  *
 609  * Returns 0 on success, negative value otherwise.
 610  */
 611 static int tomoyo_environ(struct tomoyo_execve *ee)
 612 {
 613         struct tomoyo_request_info *r = &ee->r;
 614         struct linux_binprm *bprm = ee->bprm;
 615         /* env_page.data is allocated by tomoyo_dump_page(). */
 616         struct tomoyo_page_dump env_page = { };
 617         char *arg_ptr; /* Size is TOMOYO_EXEC_TMPSIZE bytes */
 618         int arg_len = 0;
 619         unsigned long pos = bprm->p;
 620         int offset = pos % PAGE_SIZE;
 621         int argv_count = bprm->argc;
 622         int envp_count = bprm->envc;
 623         int error = -ENOMEM;
 624
 625         ee->r.type = TOMOYO_MAC_ENVIRON;
 626         ee->r.profile = r->domain->profile;
 627         ee->r.mode = tomoyo_get_mode(r->domain->ns, ee->r.profile,
 628                                      TOMOYO_MAC_ENVIRON);
 629         if (!r->mode || !envp_count)
 630                 return 0;
 631         arg_ptr = kzalloc(TOMOYO_EXEC_TMPSIZE, GFP_NOFS);
 632         if (!arg_ptr)
 633                 goto out;
 634         while (error == -ENOMEM) {
 635                 if (!tomoyo_dump_page(bprm, pos, &env_page))
 636                         goto out;
 637                 pos += PAGE_SIZE - offset;
 638                 /* Read. */
 639                 while (argv_count && offset < PAGE_SIZE) {
 640                         if (!env_page.data[offset++])
 641                                 argv_count--;
 642                 }
 643                 if (argv_count) {
 644                         offset = 0;
 645                         continue;
 646                 }
 647                 while (offset < PAGE_SIZE) {
 648                         const unsigned char c = env_page.data[offset++];
 649
 650                         if (c && arg_len < TOMOYO_EXEC_TMPSIZE - 10) {
 651                                 if (c == '=') {
 652                                         arg_ptr[arg_len++] = '\0';
 653                                 } else if (c == '\\') {
 654                                         arg_ptr[arg_len++] = '\\';
 655                                         arg_ptr[arg_len++] = '\\';
 656                                 } else if (c > ' ' && c < 127) {
 657                                         arg_ptr[arg_len++] = c;
 658                                 } else {
 659                                         arg_ptr[arg_len++] = '\\';
 660                                         arg_ptr[arg_len++] = (c >> 6) + '0';
 661                                         arg_ptr[arg_len++]
 662                                                 = ((c >> 3) & 7) + '0';
 663                                         arg_ptr[arg_len++] = (c & 7) + '0';
 664                                 }
 665                         } else {
 666                                 arg_ptr[arg_len] = '\0';
 667                         }
 668                         if (c)
 669                                 continue;
 670                         if (tomoyo_env_perm(r, arg_ptr)) {
 671                                 error = -EPERM;
 672                                 break;
 673                         }
 674                         if (!--envp_count) {
 675                                 error = 0;
 676                                 break;
 677                         }
 678                         arg_len = 0;
 679                 }
 680                 offset = 0;
 681         }
 682 out:
 683         if (r->mode != TOMOYO_CONFIG_ENFORCING)
 684                 error = 0;
 685         kfree(env_page.data);
 686         kfree(arg_ptr);
 687         return error;
 688 }
 689
 690 /**
 691  * tomoyo_find_next_domain - Find a domain.
 692  *
 693  * @bprm: Pointer to "struct linux_binprm".
 694  *
 695  * Returns 0 on success, negative value otherwise.
 696  *
 697  * Caller holds tomoyo_read_lock().
 698  */
 699 int tomoyo_find_next_domain(struct linux_binprm *bprm)
 700 {
 701         struct tomoyo_domain_info *old_domain = tomoyo_domain();
 702         struct tomoyo_domain_info *domain = NULL;
 703         const char *original_name = bprm->filename;
 704         int retval = -ENOMEM;
 705         bool reject_on_transition_failure = false;
 706         const struct tomoyo_path_info *candidate;
 707         struct tomoyo_path_info exename;
 708         struct tomoyo_execve *ee = kzalloc(sizeof(*ee), GFP_NOFS);
 709
 710         if (!ee)
 711                 return -ENOMEM;
 712         ee->tmp = kzalloc(TOMOYO_EXEC_TMPSIZE, GFP_NOFS);
 713         if (!ee->tmp) {
 714                 kfree(ee);
 715                 return -ENOMEM;
 716         }
 717         /* ee->dump->data is allocated by tomoyo_dump_page(). */
 718         tomoyo_init_request_info(&ee->r, NULL, TOMOYO_MAC_FILE_EXECUTE);
 719         ee->r.ee = ee;
 720         ee->bprm = bprm;
 721         ee->r.obj = &ee->obj;
 722         ee->obj.path1 = bprm->file->f_path;
 723         /* Get symlink's pathname of program. */
 724         retval = -ENOENT;
 725         exename.name = tomoyo_realpath_nofollow(original_name);
 726         if (!exename.name)
 727                 goto out;
 728         tomoyo_fill_path_info(&exename);
 729 retry:
 730         /* Check 'aggregator' directive. */
 731         {
 732                 struct tomoyo_aggregator *ptr;
 733                 struct list_head *list =
 734                         &old_domain->ns->policy_list[TOMOYO_ID_AGGREGATOR];
 735
 736                 /* Check 'aggregator' directive. */
 737                 candidate = &exename;
 738                 list_for_each_entry_rcu(ptr, list, head.list) {
 739                         if (ptr->head.is_deleted ||
 740                             !tomoyo_path_matches_pattern(&exename,
 741                                                          ptr->original_name))
 742                                 continue;
 743                         candidate = ptr->aggregated_name;
 744                         break;
 745                 }
 746         }
 747
 748         /* Check execute permission. */
 749         retval = tomoyo_execute_permission(&ee->r, candidate);
 750         if (retval == TOMOYO_RETRY_REQUEST)
 751                 goto retry;
 752         if (retval < 0)
 753                 goto out;
 754         /*
 755          * To be able to specify domainnames with wildcards, use the
 756          * pathname specified in the policy (which may contain
 757          * wildcard) rather than the pathname passed to execve()
 758          * (which never contains wildcard).
 759          */
 760         if (ee->r.param.path.matched_path)
 761                 candidate = ee->r.param.path.matched_path;
 762
 763         /*
 764          * Check for domain transition preference if "file execute" matched.
 765          * If preference is given, make do_execve() fail if domain transition
 766          * has failed, for domain transition preference should be used with
 767          * destination domain defined.
 768          */
 769         if (ee->transition) {
 770                 const char *domainname = ee->transition->name;
 771
 772                 reject_on_transition_failure = true;
 773                 if (!strcmp(domainname, "keep"))
 774                         goto force_keep_domain;
 775                 if (!strcmp(domainname, "child"))
 776                         goto force_child_domain;
 777                 if (!strcmp(domainname, "reset"))
 778                         goto force_reset_domain;
 779                 if (!strcmp(domainname, "initialize"))
 780                         goto force_initialize_domain;
 781                 if (!strcmp(domainname, "parent")) {
 782                         char *cp;
 783
 784                         strncpy(ee->tmp, old_domain->domainname->name,
 785                                 TOMOYO_EXEC_TMPSIZE - 1);
 786                         cp = strrchr(ee->tmp, ' ');
 787                         if (cp)
 788                                 *cp = '\0';
 789                 } else if (*domainname == '<')
 790                         strncpy(ee->tmp, domainname, TOMOYO_EXEC_TMPSIZE - 1);
 791                 else
 792                         snprintf(ee->tmp, TOMOYO_EXEC_TMPSIZE - 1, "%s %s",
 793                                  old_domain->domainname->name, domainname);
 794                 goto force_jump_domain;
 795         }
 796         /*
 797          * No domain transition preference specified.
 798          * Calculate domain to transit to.
 799          */
 800         switch (tomoyo_transition_type(old_domain->ns, old_domain->domainname,
 801                                        candidate)) {
 802         case TOMOYO_TRANSITION_CONTROL_RESET:
 803 force_reset_domain:
 804                 /* Transit to the root of specified namespace. */
 805                 snprintf(ee->tmp, TOMOYO_EXEC_TMPSIZE - 1, "<%s>",
 806                          candidate->name);
 807                 /*
 808                  * Make do_execve() fail if domain transition across namespaces
 809                  * has failed.
 810                  */
 811                 reject_on_transition_failure = true;
 812                 break;
 813         case TOMOYO_TRANSITION_CONTROL_INITIALIZE:
 814 force_initialize_domain:
 815                 /* Transit to the child of current namespace's root. */
 816                 snprintf(ee->tmp, TOMOYO_EXEC_TMPSIZE - 1, "%s %s",
 817                          old_domain->ns->name, candidate->name);
 818                 break;
 819         case TOMOYO_TRANSITION_CONTROL_KEEP:
 820 force_keep_domain:
 821                 /* Keep current domain. */
 822                 domain = old_domain;
 823                 break;
 824         default:
 825                 if (old_domain == &tomoyo_kernel_domain &&
 826                     !tomoyo_policy_loaded) {
 827                         /*
 828                          * Needn't to transit from kernel domain before
 829                          * starting /sbin/init. But transit from kernel domain
 830                          * if executing initializers because they might start
 831                          * before /sbin/init.
 832                          */
 833                         domain = old_domain;
 834                         break;
 835                 }
 836 force_child_domain:
 837                 /* Normal domain transition. */
 838                 snprintf(ee->tmp, TOMOYO_EXEC_TMPSIZE - 1, "%s %s",
 839                          old_domain->domainname->name, candidate->name);
 840                 break;
 841         }
 842 force_jump_domain:
 843         if (!domain)
 844                 domain = tomoyo_assign_domain(ee->tmp, true);
 845         if (domain)
 846                 retval = 0;
 847         else if (reject_on_transition_failure) {
 848                 pr_warn("ERROR: Domain '%s' not ready.\n", ee->tmp);
 849                 retval = -ENOMEM;
 850         } else if (ee->r.mode == TOMOYO_CONFIG_ENFORCING)
 851                 retval = -ENOMEM;
 852         else {
 853                 retval = 0;
 854                 if (!old_domain->flags[TOMOYO_DIF_TRANSITION_FAILED]) {
 855                         old_domain->flags[TOMOYO_DIF_TRANSITION_FAILED] = true;
 856                         ee->r.granted = false;
 857                         tomoyo_write_log(&ee->r, "%s", tomoyo_dif
 858                                          [TOMOYO_DIF_TRANSITION_FAILED]);
 859                         pr_warn("ERROR: Domain '%s' not defined.\n", ee->tmp);
 860                 }
 861         }
 862  out:
 863         if (!domain)
 864                 domain = old_domain;
 865         /* Update reference count on "struct tomoyo_domain_info". */
 866         {
 867                 struct tomoyo_task *s = tomoyo_task(current);
 868
 869                 s->old_domain_info = s->domain_info;
 870                 s->domain_info = domain;
 871                 atomic_inc(&domain->users);
 872         }
 873         kfree(exename.name);
 874         if (!retval) {
 875                 ee->r.domain = domain;
 876                 retval = tomoyo_environ(ee);
 877         }
 878         kfree(ee->tmp);
 879         kfree(ee->dump.data);
 880         kfree(ee);
 881         return retval;
 882 }
 883
 884 /**
 885  * tomoyo_dump_page - Dump a page to buffer.
 886  *
 887  * @bprm: Pointer to "struct linux_binprm".
 888  * @pos:  Location to dump.
 889  * @dump: Poiner to "struct tomoyo_page_dump".
 890  *
 891  * Returns true on success, false otherwise.
 892  */
 893 bool tomoyo_dump_page(struct linux_binprm *bprm, unsigned long pos,
 894                       struct tomoyo_page_dump *dump)
 895 {
 896         struct page *page;
 897
 898         /* dump->data is released by tomoyo_find_next_domain(). */
 899         if (!dump->data) {
 900                 dump->data = kzalloc(PAGE_SIZE, GFP_NOFS);
 901                 if (!dump->data)
 902                         return false;
 903         }
 904         /* Same with get_arg_page(bprm, pos, 0) in fs/exec.c */
 905 #ifdef CONFIG_MMU
 906         /*
 907          * This is called at execve() time in order to dig around
 908          * in the argv/environment of the new proceess
 909          * (represented by bprm).  'current' is the process doing
 910          * the execve().
 911          */
 912         if (get_user_pages_remote(current, bprm->mm, pos, 1,
 913                                 FOLL_FORCE, &page, NULL, NULL) <= 0)
 914                 return false;
 915 #else
 916         page = bprm->page[pos / PAGE_SIZE];
 917 #endif
 918         if (page != dump->page) {
 919                 const unsigned int offset = pos % PAGE_SIZE;
 920                 /*
 921                  * Maybe kmap()/kunmap() should be used here.
 922                  * But remove_arg_zero() uses kmap_atomic()/kunmap_atomic().
 923                  * So do I.
 924                  */
 925                 char *kaddr = kmap_atomic(page);
 926
 927                 dump->page = page;
 928                 memcpy(dump->data + offset, kaddr + offset,
 929                        PAGE_SIZE - offset);
 930                 kunmap_atomic(kaddr);
 931         }
 932         /* Same with put_arg_page(page) in fs/exec.c */
 933 #ifdef CONFIG_MMU
 934         put_page(page);
 935 #endif
 936         return true;
 937 }