security/tomoyo/domain.c

   1 /*
   2  * security/tomoyo/domain.c
   3  *
   4  * Domain transition functions for TOMOYO.
   5  *
   6  * Copyright (C) 2005-2010  NTT DATA CORPORATION
   7  */
   8
   9 #include "common.h"
  10 #include <linux/binfmts.h>
  11 #include <linux/slab.h>
  12
  13 /* Variables definitions.*/
  14
  15 /* The initial domain. */
  16 struct tomoyo_domain_info tomoyo_kernel_domain;
  17
  18 /**
  19  * tomoyo_update_policy - Update an entry for exception policy.
  20  *
  21  * @new_entry:       Pointer to "struct tomoyo_acl_info".
  22  * @size:            Size of @new_entry in bytes.
  23  * @is_delete:       True if it is a delete request.
  24  * @list:            Pointer to "struct list_head".
  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                          bool is_delete, struct list_head *list,
  33                          bool (*check_duplicate) (const struct tomoyo_acl_head
  34                                                   *,
  35                                                   const struct tomoyo_acl_head
  36                                                   *))
  37 {
  38         int error = is_delete ? -ENOENT : -ENOMEM;
  39         struct tomoyo_acl_head *entry;
  40
  41         if (mutex_lock_interruptible(&tomoyo_policy_lock))
  42                 return -ENOMEM;
  43         list_for_each_entry_rcu(entry, list, list) {
  44                 if (!check_duplicate(entry, new_entry))
  45                         continue;
  46                 entry->is_deleted = is_delete;
  47                 error = 0;
  48                 break;
  49         }
  50         if (error && !is_delete) {
  51                 entry = tomoyo_commit_ok(new_entry, size);
  52                 if (entry) {
  53                         list_add_tail_rcu(&entry->list, list);
  54                         error = 0;
  55                 }
  56         }
  57         mutex_unlock(&tomoyo_policy_lock);
  58         return error;
  59 }
  60
  61 /**
  62  * tomoyo_update_domain - Update an entry for domain policy.
  63  *
  64  * @new_entry:       Pointer to "struct tomoyo_acl_info".
  65  * @size:            Size of @new_entry in bytes.
  66  * @is_delete:       True if it is a delete request.
  67  * @domain:          Pointer to "struct tomoyo_domain_info".
  68  * @check_duplicate: Callback function to find duplicated entry.
  69  * @merge_duplicate: Callback function to merge duplicated entry.
  70  *
  71  * Returns 0 on success, negative value otherwise.
  72  *
  73  * Caller holds tomoyo_read_lock().
  74  */
  75 int tomoyo_update_domain(struct tomoyo_acl_info *new_entry, const int size,
  76                          bool is_delete, struct tomoyo_domain_info *domain,
  77                          bool (*check_duplicate) (const struct tomoyo_acl_info
  78                                                   *,
  79                                                   const struct tomoyo_acl_info
  80                                                   *),
  81                          bool (*merge_duplicate) (struct tomoyo_acl_info *,
  82                                                   struct tomoyo_acl_info *,
  83                                                   const bool))
  84 {
  85         int error = is_delete ? -ENOENT : -ENOMEM;
  86         struct tomoyo_acl_info *entry;
  87
  88         if (mutex_lock_interruptible(&tomoyo_policy_lock))
  89                 return error;
  90         list_for_each_entry_rcu(entry, &domain->acl_info_list, list) {
  91                 if (!check_duplicate(entry, new_entry))
  92                         continue;
  93                 if (merge_duplicate)
  94                         entry->is_deleted = merge_duplicate(entry, new_entry,
  95                                                             is_delete);
  96                 else
  97                         entry->is_deleted = is_delete;
  98                 error = 0;
  99                 break;
 100         }
 101         if (error && !is_delete) {
 102                 entry = tomoyo_commit_ok(new_entry, size);
 103                 if (entry) {
 104                         list_add_tail_rcu(&entry->list, &domain->acl_info_list);
 105                         error = 0;
 106                 }
 107         }
 108         mutex_unlock(&tomoyo_policy_lock);
 109         return error;
 110 }
 111
 112 void tomoyo_check_acl(struct tomoyo_request_info *r,
 113                       bool (*check_entry) (struct tomoyo_request_info *,
 114                                            const struct tomoyo_acl_info *))
 115 {
 116         const struct tomoyo_domain_info *domain = r->domain;
 117         struct tomoyo_acl_info *ptr;
 118
 119         list_for_each_entry_rcu(ptr, &domain->acl_info_list, list) {
 120                 if (ptr->is_deleted || ptr->type != r->param_type)
 121                         continue;
 122                 if (check_entry(r, ptr)) {
 123                         r->granted = true;
 124                         return;
 125                 }
 126         }
 127         r->granted = false;
 128 }
 129
 130 /* The list for "struct tomoyo_domain_info". */
 131 LIST_HEAD(tomoyo_domain_list);
 132
 133 struct list_head tomoyo_policy_list[TOMOYO_MAX_POLICY];
 134 struct list_head tomoyo_group_list[TOMOYO_MAX_GROUP];
 135
 136 /**
 137  * tomoyo_last_word - Get last component of a domainname.
 138  *
 139  * @domainname: Domainname to check.
 140  *
 141  * Returns the last word of @domainname.
 142  */
 143 static const char *tomoyo_last_word(const char *name)
 144 {
 145         const char *cp = strrchr(name, ' ');
 146         if (cp)
 147                 return cp + 1;
 148         return name;
 149 }
 150
 151 static bool tomoyo_same_transition_control(const struct tomoyo_acl_head *a,
 152                                            const struct tomoyo_acl_head *b)
 153 {
 154         const struct tomoyo_transition_control *p1 = container_of(a,
 155                                                                   typeof(*p1),
 156                                                                   head);
 157         const struct tomoyo_transition_control *p2 = container_of(b,
 158                                                                   typeof(*p2),
 159                                                                   head);
 160         return p1->type == p2->type && p1->is_last_name == p2->is_last_name
 161                 && p1->domainname == p2->domainname
 162                 && p1->program == p2->program;
 163 }
 164
 165 /**
 166  * tomoyo_update_transition_control_entry - Update "struct tomoyo_transition_control" list.
 167  *
 168  * @domainname: The name of domain. Maybe NULL.
 169  * @program:    The name of program. Maybe NULL.
 170  * @type:       Type of transition.
 171  * @is_delete:  True if it is a delete request.
 172  *
 173  * Returns 0 on success, negative value otherwise.
 174  */
 175 static int tomoyo_update_transition_control_entry(const char *domainname,
 176                                                   const char *program,
 177                                                   const u8 type,
 178                                                   const bool is_delete)
 179 {
 180         struct tomoyo_transition_control e = { .type = type };
 181         int error = is_delete ? -ENOENT : -ENOMEM;
 182         if (program) {
 183                 if (!tomoyo_correct_path(program))
 184                         return -EINVAL;
 185                 e.program = tomoyo_get_name(program);
 186                 if (!e.program)
 187                         goto out;
 188         }
 189         if (domainname) {
 190                 if (!tomoyo_correct_domain(domainname)) {
 191                         if (!tomoyo_correct_path(domainname))
 192                                 goto out;
 193                         e.is_last_name = true;
 194                 }
 195                 e.domainname = tomoyo_get_name(domainname);
 196                 if (!e.domainname)
 197                         goto out;
 198         }
 199         error = tomoyo_update_policy(&e.head, sizeof(e), is_delete,
 200                                      &tomoyo_policy_list
 201                                      [TOMOYO_ID_TRANSITION_CONTROL],
 202                                      tomoyo_same_transition_control);
 203  out:
 204         tomoyo_put_name(e.domainname);
 205         tomoyo_put_name(e.program);
 206         return error;
 207 }
 208
 209 /**
 210  * tomoyo_write_transition_control - Write "struct tomoyo_transition_control" list.
 211  *
 212  * @data:      String to parse.
 213  * @is_delete: True if it is a delete request.
 214  * @type:      Type of this entry.
 215  *
 216  * Returns 0 on success, negative value otherwise.
 217  */
 218 int tomoyo_write_transition_control(char *data, const bool is_delete,
 219                                     const u8 type)
 220 {
 221         char *domainname = strstr(data, " from ");
 222         if (domainname) {
 223                 *domainname = '\0';
 224                 domainname += 6;
 225         } else if (type == TOMOYO_TRANSITION_CONTROL_NO_KEEP ||
 226                    type == TOMOYO_TRANSITION_CONTROL_KEEP) {
 227                 domainname = data;
 228                 data = NULL;
 229         }
 230         return tomoyo_update_transition_control_entry(domainname, data, type,
 231                                                       is_delete);
 232 }
 233
 234 /**
 235  * tomoyo_transition_type - Get domain transition type.
 236  *
 237  * @domainname: The name of domain.
 238  * @program:    The name of program.
 239  *
 240  * Returns TOMOYO_TRANSITION_CONTROL_INITIALIZE if executing @program
 241  * reinitializes domain transition, TOMOYO_TRANSITION_CONTROL_KEEP if executing
 242  * @program suppresses domain transition, others otherwise.
 243  *
 244  * Caller holds tomoyo_read_lock().
 245  */
 246 static u8 tomoyo_transition_type(const struct tomoyo_path_info *domainname,
 247                                  const struct tomoyo_path_info *program)
 248 {
 249         const struct tomoyo_transition_control *ptr;
 250         const char *last_name = tomoyo_last_word(domainname->name);
 251         u8 type;
 252         for (type = 0; type < TOMOYO_MAX_TRANSITION_TYPE; type++) {
 253  next:
 254                 list_for_each_entry_rcu(ptr, &tomoyo_policy_list
 255                                         [TOMOYO_ID_TRANSITION_CONTROL],
 256                                         head.list) {
 257                         if (ptr->head.is_deleted || ptr->type != type)
 258                                 continue;
 259                         if (ptr->domainname) {
 260                                 if (!ptr->is_last_name) {
 261                                         if (ptr->domainname != domainname)
 262                                                 continue;
 263                                 } else {
 264                                         /*
 265                                          * Use direct strcmp() since this is
 266                                          * unlikely used.
 267                                          */
 268                                         if (strcmp(ptr->domainname->name,
 269                                                    last_name))
 270                                                 continue;
 271                                 }
 272                         }
 273                         if (ptr->program &&
 274                             tomoyo_pathcmp(ptr->program, program))
 275                                 continue;
 276                         if (type == TOMOYO_TRANSITION_CONTROL_NO_INITIALIZE) {
 277                                 /*
 278                                  * Do not check for initialize_domain if
 279                                  * no_initialize_domain matched.
 280                                  */
 281                                 type = TOMOYO_TRANSITION_CONTROL_NO_KEEP;
 282                                 goto next;
 283                         }
 284                         goto done;
 285                 }
 286         }
 287  done:
 288         return type;
 289 }
 290
 291 static bool tomoyo_same_aggregator(const struct tomoyo_acl_head *a,
 292                                    const struct tomoyo_acl_head *b)
 293 {
 294         const struct tomoyo_aggregator *p1 = container_of(a, typeof(*p1), head);
 295         const struct tomoyo_aggregator *p2 = container_of(b, typeof(*p2), head);
 296         return p1->original_name == p2->original_name &&
 297                 p1->aggregated_name == p2->aggregated_name;
 298 }
 299
 300 /**
 301  * tomoyo_update_aggregator_entry - Update "struct tomoyo_aggregator" list.
 302  *
 303  * @original_name:   The original program's name.
 304  * @aggregated_name: The program name to use.
 305  * @is_delete:       True if it is a delete request.
 306  *
 307  * Returns 0 on success, negative value otherwise.
 308  *
 309  * Caller holds tomoyo_read_lock().
 310  */
 311 static int tomoyo_update_aggregator_entry(const char *original_name,
 312                                           const char *aggregated_name,
 313                                           const bool is_delete)
 314 {
 315         struct tomoyo_aggregator e = { };
 316         int error = is_delete ? -ENOENT : -ENOMEM;
 317
 318         if (!tomoyo_correct_path(original_name) ||
 319             !tomoyo_correct_path(aggregated_name))
 320                 return -EINVAL;
 321         e.original_name = tomoyo_get_name(original_name);
 322         e.aggregated_name = tomoyo_get_name(aggregated_name);
 323         if (!e.original_name || !e.aggregated_name ||
 324             e.aggregated_name->is_patterned) /* No patterns allowed. */
 325                 goto out;
 326         error = tomoyo_update_policy(&e.head, sizeof(e), is_delete,
 327                                      &tomoyo_policy_list[TOMOYO_ID_AGGREGATOR],
 328                                      tomoyo_same_aggregator);
 329  out:
 330         tomoyo_put_name(e.original_name);
 331         tomoyo_put_name(e.aggregated_name);
 332         return error;
 333 }
 334
 335 /**
 336  * tomoyo_write_aggregator - Write "struct tomoyo_aggregator" list.
 337  *
 338  * @data:      String to parse.
 339  * @is_delete: True if it is a delete request.
 340  *
 341  * Returns 0 on success, negative value otherwise.
 342  *
 343  * Caller holds tomoyo_read_lock().
 344  */
 345 int tomoyo_write_aggregator(char *data, const bool is_delete)
 346 {
 347         char *cp = strchr(data, ' ');
 348
 349         if (!cp)
 350                 return -EINVAL;
 351         *cp++ = '\0';
 352         return tomoyo_update_aggregator_entry(data, cp, is_delete);
 353 }
 354
 355 /**
 356  * tomoyo_assign_domain - Create a domain.
 357  *
 358  * @domainname: The name of domain.
 359  * @profile:    Profile number to assign if the domain was newly created.
 360  *
 361  * Returns pointer to "struct tomoyo_domain_info" on success, NULL otherwise.
 362  *
 363  * Caller holds tomoyo_read_lock().
 364  */
 365 struct tomoyo_domain_info *tomoyo_assign_domain(const char *domainname,
 366                                                 const u8 profile)
 367 {
 368         struct tomoyo_domain_info *entry;
 369         struct tomoyo_domain_info *domain = NULL;
 370         const struct tomoyo_path_info *saved_domainname;
 371         bool found = false;
 372
 373         if (!tomoyo_correct_domain(domainname))
 374                 return NULL;
 375         saved_domainname = tomoyo_get_name(domainname);
 376         if (!saved_domainname)
 377                 return NULL;
 378         entry = kzalloc(sizeof(*entry), GFP_NOFS);
 379         if (mutex_lock_interruptible(&tomoyo_policy_lock))
 380                 goto out;
 381         list_for_each_entry_rcu(domain, &tomoyo_domain_list, list) {
 382                 if (domain->is_deleted ||
 383                     tomoyo_pathcmp(saved_domainname, domain->domainname))
 384                         continue;
 385                 found = true;
 386                 break;
 387         }
 388         if (!found && tomoyo_memory_ok(entry)) {
 389                 INIT_LIST_HEAD(&entry->acl_info_list);
 390                 entry->domainname = saved_domainname;
 391                 saved_domainname = NULL;
 392                 entry->profile = profile;
 393                 list_add_tail_rcu(&entry->list, &tomoyo_domain_list);
 394                 domain = entry;
 395                 entry = NULL;
 396                 found = true;
 397         }
 398         mutex_unlock(&tomoyo_policy_lock);
 399  out:
 400         tomoyo_put_name(saved_domainname);
 401         kfree(entry);
 402         return found ? domain : NULL;
 403 }
 404
 405 /**
 406  * tomoyo_find_next_domain - Find a domain.
 407  *
 408  * @bprm: Pointer to "struct linux_binprm".
 409  *
 410  * Returns 0 on success, negative value otherwise.
 411  *
 412  * Caller holds tomoyo_read_lock().
 413  */
 414 int tomoyo_find_next_domain(struct linux_binprm *bprm)
 415 {
 416         struct tomoyo_request_info r;
 417         char *tmp = kzalloc(TOMOYO_EXEC_TMPSIZE, GFP_NOFS);
 418         struct tomoyo_domain_info *old_domain = tomoyo_domain();
 419         struct tomoyo_domain_info *domain = NULL;
 420         const char *original_name = bprm->filename;
 421         u8 mode;
 422         bool is_enforce;
 423         int retval = -ENOMEM;
 424         bool need_kfree = false;
 425         struct tomoyo_path_info rn = { }; /* real name */
 426
 427         mode = tomoyo_init_request_info(&r, NULL, TOMOYO_MAC_FILE_EXECUTE);
 428         is_enforce = (mode == TOMOYO_CONFIG_ENFORCING);
 429         if (!tmp)
 430                 goto out;
 431
 432  retry:
 433         if (need_kfree) {
 434                 kfree(rn.name);
 435                 need_kfree = false;
 436         }
 437         /* Get symlink's pathname of program. */
 438         retval = -ENOENT;
 439         rn.name = tomoyo_realpath_nofollow(original_name);
 440         if (!rn.name)
 441                 goto out;
 442         tomoyo_fill_path_info(&rn);
 443         need_kfree = true;
 444
 445         /* Check 'aggregator' directive. */
 446         {
 447                 struct tomoyo_aggregator *ptr;
 448                 list_for_each_entry_rcu(ptr, &tomoyo_policy_list
 449                                         [TOMOYO_ID_AGGREGATOR], head.list) {
 450                         if (ptr->head.is_deleted ||
 451                             !tomoyo_path_matches_pattern(&rn,
 452                                                          ptr->original_name))
 453                                 continue;
 454                         kfree(rn.name);
 455                         need_kfree = false;
 456                         /* This is OK because it is read only. */
 457                         rn = *ptr->aggregated_name;
 458                         break;
 459                 }
 460         }
 461
 462         /* Check execute permission. */
 463         retval = tomoyo_path_permission(&r, TOMOYO_TYPE_EXECUTE, &rn);
 464         if (retval == TOMOYO_RETRY_REQUEST)
 465                 goto retry;
 466         if (retval < 0)
 467                 goto out;
 468         /*
 469          * To be able to specify domainnames with wildcards, use the
 470          * pathname specified in the policy (which may contain
 471          * wildcard) rather than the pathname passed to execve()
 472          * (which never contains wildcard).
 473          */
 474         if (r.param.path.matched_path) {
 475                 if (need_kfree)
 476                         kfree(rn.name);
 477                 need_kfree = false;
 478                 /* This is OK because it is read only. */
 479                 rn = *r.param.path.matched_path;
 480         }
 481
 482         /* Calculate domain to transit to. */
 483         switch (tomoyo_transition_type(old_domain->domainname, &rn)) {
 484         case TOMOYO_TRANSITION_CONTROL_INITIALIZE:
 485                 /* Transit to the child of tomoyo_kernel_domain domain. */
 486                 snprintf(tmp, TOMOYO_EXEC_TMPSIZE - 1, TOMOYO_ROOT_NAME " "
 487                          "%s", rn.name);
 488                 break;
 489         case TOMOYO_TRANSITION_CONTROL_KEEP:
 490                 /* Keep current domain. */
 491                 domain = old_domain;
 492                 break;
 493         default:
 494                 if (old_domain == &tomoyo_kernel_domain &&
 495                     !tomoyo_policy_loaded) {
 496                         /*
 497                          * Needn't to transit from kernel domain before
 498                          * starting /sbin/init. But transit from kernel domain
 499                          * if executing initializers because they might start
 500                          * before /sbin/init.
 501                          */
 502                         domain = old_domain;
 503                 } else {
 504                         /* Normal domain transition. */
 505                         snprintf(tmp, TOMOYO_EXEC_TMPSIZE - 1, "%s %s",
 506                                  old_domain->domainname->name, rn.name);
 507                 }
 508                 break;
 509         }
 510         if (domain || strlen(tmp) >= TOMOYO_EXEC_TMPSIZE - 10)
 511                 goto done;
 512         domain = tomoyo_find_domain(tmp);
 513         if (domain)
 514                 goto done;
 515         if (is_enforce) {
 516                 int error = tomoyo_supervisor(&r, "# wants to create domain\n"
 517                                               "%s\n", tmp);
 518                 if (error == TOMOYO_RETRY_REQUEST)
 519                         goto retry;
 520                 if (error < 0)
 521                         goto done;
 522         }
 523         domain = tomoyo_assign_domain(tmp, old_domain->profile);
 524  done:
 525         if (domain)
 526                 goto out;
 527         printk(KERN_WARNING "TOMOYO-ERROR: Domain '%s' not defined.\n", tmp);
 528         if (is_enforce)
 529                 retval = -EPERM;
 530         else
 531                 old_domain->transition_failed = true;
 532  out:
 533         if (!domain)
 534                 domain = old_domain;
 535         /* Update reference count on "struct tomoyo_domain_info". */
 536         atomic_inc(&domain->users);
 537         bprm->cred->security = domain;
 538         if (need_kfree)
 539                 kfree(rn.name);
 540         kfree(tmp);
 541         return retval;
 542 }