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   1 /*
   2  * security/tomoyo/domain.c
   3  *
   4  * Implementation of the Domain-Based Mandatory Access Control.
   5  *
   6  * Copyright (C) 2005-2009  NTT DATA CORPORATION
   7  *
   8  * Version: 2.2.0   2009/04/01
   9  *
  10  */
  11
  12 #include "common.h"
  13 #include "tomoyo.h"
  14 #include "realpath.h"
  15 #include <linux/binfmts.h>
  16
  17 /* Variables definitions.*/
  18
  19 /* The initial domain. */
  20 struct tomoyo_domain_info tomoyo_kernel_domain;
  21
  22 /*
  23  * tomoyo_domain_list is used for holding list of domains.
  24  * The ->acl_info_list of "struct tomoyo_domain_info" is used for holding
  25  * permissions (e.g. "allow_read /lib/libc-2.5.so") given to each domain.
  26  *
  27  * An entry is added by
  28  *
  29  * # ( echo "<kernel>"; echo "allow_execute /sbin/init" ) > \
  30  *                                  /sys/kernel/security/tomoyo/domain_policy
  31  *
  32  * and is deleted by
  33  *
  34  * # ( echo "<kernel>"; echo "delete allow_execute /sbin/init" ) > \
  35  *                                  /sys/kernel/security/tomoyo/domain_policy
  36  *
  37  * and all entries are retrieved by
  38  *
  39  * # cat /sys/kernel/security/tomoyo/domain_policy
  40  *
  41  * A domain is added by
  42  *
  43  * # echo "<kernel>" > /sys/kernel/security/tomoyo/domain_policy
  44  *
  45  * and is deleted by
  46  *
  47  * # echo "delete <kernel>" > /sys/kernel/security/tomoyo/domain_policy
  48  *
  49  * and all domains are retrieved by
  50  *
  51  * # grep '^<kernel>' /sys/kernel/security/tomoyo/domain_policy
  52  *
  53  * Normally, a domainname is monotonically getting longer because a domainname
  54  * which the process will belong to if an execve() operation succeeds is
  55  * defined as a concatenation of "current domainname" + "pathname passed to
  56  * execve()".
  57  * See tomoyo_domain_initializer_list and tomoyo_domain_keeper_list for
  58  * exceptions.
  59  */
  60 LIST_HEAD(tomoyo_domain_list);
  61
  62 /*
  63  * tomoyo_domain_initializer_entry is a structure which is used for holding
  64  * "initialize_domain" and "no_initialize_domain" entries.
  65  * It has following fields.
  66  *
  67  *  (1) "list" which is linked to tomoyo_domain_initializer_list .
  68  *  (2) "domainname" which is "a domainname" or "the last component of a
  69  *      domainname". This field is NULL if "from" clause is not specified.
  70  *  (3) "program" which is a program's pathname.
  71  *  (4) "is_deleted" is a bool which is true if marked as deleted, false
  72  *      otherwise.
  73  *  (5) "is_not" is a bool which is true if "no_initialize_domain", false
  74  *      otherwise.
  75  *  (6) "is_last_name" is a bool which is true if "domainname" is "the last
  76  *      component of a domainname", false otherwise.
  77  */
  78 struct tomoyo_domain_initializer_entry {
  79         struct list_head list;
  80         const struct tomoyo_path_info *domainname;    /* This may be NULL */
  81         const struct tomoyo_path_info *program;
  82         bool is_deleted;
  83         bool is_not;       /* True if this entry is "no_initialize_domain".  */
  84         /* True if the domainname is tomoyo_get_last_name(). */
  85         bool is_last_name;
  86 };
  87
  88 /*
  89  * tomoyo_domain_keeper_entry is a structure which is used for holding
  90  * "keep_domain" and "no_keep_domain" entries.
  91  * It has following fields.
  92  *
  93  *  (1) "list" which is linked to tomoyo_domain_keeper_list .
  94  *  (2) "domainname" which is "a domainname" or "the last component of a
  95  *      domainname".
  96  *  (3) "program" which is a program's pathname.
  97  *      This field is NULL if "from" clause is not specified.
  98  *  (4) "is_deleted" is a bool which is true if marked as deleted, false
  99  *      otherwise.
 100  *  (5) "is_not" is a bool which is true if "no_initialize_domain", false
 101  *      otherwise.
 102  *  (6) "is_last_name" is a bool which is true if "domainname" is "the last
 103  *      component of a domainname", false otherwise.
 104  */
 105 struct tomoyo_domain_keeper_entry {
 106         struct list_head list;
 107         const struct tomoyo_path_info *domainname;
 108         const struct tomoyo_path_info *program;       /* This may be NULL */
 109         bool is_deleted;
 110         bool is_not;       /* True if this entry is "no_keep_domain".        */
 111         /* True if the domainname is tomoyo_get_last_name(). */
 112         bool is_last_name;
 113 };
 114
 115 /*
 116  * tomoyo_alias_entry is a structure which is used for holding "alias" entries.
 117  * It has following fields.
 118  *
 119  *  (1) "list" which is linked to tomoyo_alias_list .
 120  *  (2) "original_name" which is a dereferenced pathname.
 121  *  (3) "aliased_name" which is a symlink's pathname.
 122  *  (4) "is_deleted" is a bool which is true if marked as deleted, false
 123  *      otherwise.
 124  */
 125 struct tomoyo_alias_entry {
 126         struct list_head list;
 127         const struct tomoyo_path_info *original_name;
 128         const struct tomoyo_path_info *aliased_name;
 129         bool is_deleted;
 130 };
 131
 132 /**
 133  * tomoyo_get_last_name - Get last component of a domainname.
 134  *
 135  * @domain: Pointer to "struct tomoyo_domain_info".
 136  *
 137  * Returns the last component of the domainname.
 138  */
 139 const char *tomoyo_get_last_name(const struct tomoyo_domain_info *domain)
 140 {
 141         const char *cp0 = domain->domainname->name;
 142         const char *cp1 = strrchr(cp0, ' ');
 143
 144         if (cp1)
 145                 return cp1 + 1;
 146         return cp0;
 147 }
 148
 149 /*
 150  * tomoyo_domain_initializer_list is used for holding list of programs which
 151  * triggers reinitialization of domainname. Normally, a domainname is
 152  * monotonically getting longer. But sometimes, we restart daemon programs.
 153  * It would be convenient for us that "a daemon started upon system boot" and
 154  * "the daemon restarted from console" belong to the same domain. Thus, TOMOYO
 155  * provides a way to shorten domainnames.
 156  *
 157  * An entry is added by
 158  *
 159  * # echo 'initialize_domain /usr/sbin/httpd' > \
 160  *                               /sys/kernel/security/tomoyo/exception_policy
 161  *
 162  * and is deleted by
 163  *
 164  * # echo 'delete initialize_domain /usr/sbin/httpd' > \
 165  *                               /sys/kernel/security/tomoyo/exception_policy
 166  *
 167  * and all entries are retrieved by
 168  *
 169  * # grep ^initialize_domain /sys/kernel/security/tomoyo/exception_policy
 170  *
 171  * In the example above, /usr/sbin/httpd will belong to
 172  * "<kernel> /usr/sbin/httpd" domain.
 173  *
 174  * You may specify a domainname using "from" keyword.
 175  * "initialize_domain /usr/sbin/httpd from <kernel> /etc/rc.d/init.d/httpd"
 176  * will cause "/usr/sbin/httpd" executed from "<kernel> /etc/rc.d/init.d/httpd"
 177  * domain to belong to "<kernel> /usr/sbin/httpd" domain.
 178  *
 179  * You may add "no_" prefix to "initialize_domain".
 180  * "initialize_domain /usr/sbin/httpd" and
 181  * "no_initialize_domain /usr/sbin/httpd from <kernel> /etc/rc.d/init.d/httpd"
 182  * will cause "/usr/sbin/httpd" to belong to "<kernel> /usr/sbin/httpd" domain
 183  * unless executed from "<kernel> /etc/rc.d/init.d/httpd" domain.
 184  */
 185 static LIST_HEAD(tomoyo_domain_initializer_list);
 186
 187 /**
 188  * tomoyo_update_domain_initializer_entry - Update "struct tomoyo_domain_initializer_entry" list.
 189  *
 190  * @domainname: The name of domain. May be NULL.
 191  * @program:    The name of program.
 192  * @is_not:     True if it is "no_initialize_domain" entry.
 193  * @is_delete:  True if it is a delete request.
 194  *
 195  * Returns 0 on success, negative value otherwise.
 196  *
 197  * Caller holds tomoyo_read_lock().
 198  */
 199 static int tomoyo_update_domain_initializer_entry(const char *domainname,
 200                                                   const char *program,
 201                                                   const bool is_not,
 202                                                   const bool is_delete)
 203 {
 204         struct tomoyo_domain_initializer_entry *entry = NULL;
 205         struct tomoyo_domain_initializer_entry *ptr;
 206         const struct tomoyo_path_info *saved_program;
 207         const struct tomoyo_path_info *saved_domainname = NULL;
 208         int error = is_delete ? -ENOENT : -ENOMEM;
 209         bool is_last_name = false;
 210
 211         if (!tomoyo_is_correct_path(program, 1, -1, -1, __func__))
 212                 return -EINVAL; /* No patterns allowed. */
 213         if (domainname) {
 214                 if (!tomoyo_is_domain_def(domainname) &&
 215                     tomoyo_is_correct_path(domainname, 1, -1, -1, __func__))
 216                         is_last_name = true;
 217                 else if (!tomoyo_is_correct_domain(domainname, __func__))
 218                         return -EINVAL;
 219                 saved_domainname = tomoyo_save_name(domainname);
 220                 if (!saved_domainname)
 221                         goto out;
 222         }
 223         saved_program = tomoyo_save_name(program);
 224         if (!saved_program)
 225                 goto out;
 226         if (!is_delete)
 227                 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
 228         mutex_lock(&tomoyo_policy_lock);
 229         list_for_each_entry_rcu(ptr, &tomoyo_domain_initializer_list, list) {
 230                 if (ptr->is_not != is_not ||
 231                     ptr->domainname != saved_domainname ||
 232                     ptr->program != saved_program)
 233                         continue;
 234                 ptr->is_deleted = is_delete;
 235                 error = 0;
 236                 break;
 237         }
 238         if (!is_delete && error && tomoyo_memory_ok(entry)) {
 239                 entry->domainname = saved_domainname;
 240                 entry->program = saved_program;
 241                 entry->is_not = is_not;
 242                 entry->is_last_name = is_last_name;
 243                 list_add_tail_rcu(&entry->list,
 244                                   &tomoyo_domain_initializer_list);
 245                 entry = NULL;
 246                 error = 0;
 247         }
 248         mutex_unlock(&tomoyo_policy_lock);
 249  out:
 250         kfree(entry);
 251         return error;
 252 }
 253
 254 /**
 255  * tomoyo_read_domain_initializer_policy - Read "struct tomoyo_domain_initializer_entry" list.
 256  *
 257  * @head: Pointer to "struct tomoyo_io_buffer".
 258  *
 259  * Returns true on success, false otherwise.
 260  *
 261  * Caller holds tomoyo_read_lock().
 262  */
 263 bool tomoyo_read_domain_initializer_policy(struct tomoyo_io_buffer *head)
 264 {
 265         struct list_head *pos;
 266         bool done = true;
 267
 268         list_for_each_cookie(pos, head->read_var2,
 269                              &tomoyo_domain_initializer_list) {
 270                 const char *no;
 271                 const char *from = "";
 272                 const char *domain = "";
 273                 struct tomoyo_domain_initializer_entry *ptr;
 274                 ptr = list_entry(pos, struct tomoyo_domain_initializer_entry,
 275                                   list);
 276                 if (ptr->is_deleted)
 277                         continue;
 278                 no = ptr->is_not ? "no_" : "";
 279                 if (ptr->domainname) {
 280                         from = " from ";
 281                         domain = ptr->domainname->name;
 282                 }
 283                 done = tomoyo_io_printf(head,
 284                                         "%s" TOMOYO_KEYWORD_INITIALIZE_DOMAIN
 285                                         "%s%s%s\n", no, ptr->program->name,
 286                                         from, domain);
 287                 if (!done)
 288                         break;
 289         }
 290         return done;
 291 }
 292
 293 /**
 294  * tomoyo_write_domain_initializer_policy - Write "struct tomoyo_domain_initializer_entry" list.
 295  *
 296  * @data:      String to parse.
 297  * @is_not:    True if it is "no_initialize_domain" entry.
 298  * @is_delete: True if it is a delete request.
 299  *
 300  * Returns 0 on success, negative value otherwise.
 301  *
 302  * Caller holds tomoyo_read_lock().
 303  */
 304 int tomoyo_write_domain_initializer_policy(char *data, const bool is_not,
 305                                            const bool is_delete)
 306 {
 307         char *cp = strstr(data, " from ");
 308
 309         if (cp) {
 310                 *cp = '\0';
 311                 return tomoyo_update_domain_initializer_entry(cp + 6, data,
 312                                                               is_not,
 313                                                               is_delete);
 314         }
 315         return tomoyo_update_domain_initializer_entry(NULL, data, is_not,
 316                                                       is_delete);
 317 }
 318
 319 /**
 320  * tomoyo_is_domain_initializer - Check whether the given program causes domainname reinitialization.
 321  *
 322  * @domainname: The name of domain.
 323  * @program:    The name of program.
 324  * @last_name:  The last component of @domainname.
 325  *
 326  * Returns true if executing @program reinitializes domain transition,
 327  * false otherwise.
 328  *
 329  * Caller holds tomoyo_read_lock().
 330  */
 331 static bool tomoyo_is_domain_initializer(const struct tomoyo_path_info *
 332                                          domainname,
 333                                          const struct tomoyo_path_info *program,
 334                                          const struct tomoyo_path_info *
 335                                          last_name)
 336 {
 337         struct tomoyo_domain_initializer_entry *ptr;
 338         bool flag = false;
 339
 340         list_for_each_entry_rcu(ptr, &tomoyo_domain_initializer_list, list) {
 341                 if (ptr->is_deleted)
 342                         continue;
 343                 if (ptr->domainname) {
 344                         if (!ptr->is_last_name) {
 345                                 if (ptr->domainname != domainname)
 346                                         continue;
 347                         } else {
 348                                 if (tomoyo_pathcmp(ptr->domainname, last_name))
 349                                         continue;
 350                         }
 351                 }
 352                 if (tomoyo_pathcmp(ptr->program, program))
 353                         continue;
 354                 if (ptr->is_not) {
 355                         flag = false;
 356                         break;
 357                 }
 358                 flag = true;
 359         }
 360         return flag;
 361 }
 362
 363 /*
 364  * tomoyo_domain_keeper_list is used for holding list of domainnames which
 365  * suppresses domain transition. Normally, a domainname is monotonically
 366  * getting longer. But sometimes, we want to suppress domain transition.
 367  * It would be convenient for us that programs executed from a login session
 368  * belong to the same domain. Thus, TOMOYO provides a way to suppress domain
 369  * transition.
 370  *
 371  * An entry is added by
 372  *
 373  * # echo 'keep_domain <kernel> /usr/sbin/sshd /bin/bash' > \
 374  *                              /sys/kernel/security/tomoyo/exception_policy
 375  *
 376  * and is deleted by
 377  *
 378  * # echo 'delete keep_domain <kernel> /usr/sbin/sshd /bin/bash' > \
 379  *                              /sys/kernel/security/tomoyo/exception_policy
 380  *
 381  * and all entries are retrieved by
 382  *
 383  * # grep ^keep_domain /sys/kernel/security/tomoyo/exception_policy
 384  *
 385  * In the example above, any process which belongs to
 386  * "<kernel> /usr/sbin/sshd /bin/bash" domain will remain in that domain,
 387  * unless explicitly specified by "initialize_domain" or "no_keep_domain".
 388  *
 389  * You may specify a program using "from" keyword.
 390  * "keep_domain /bin/pwd from <kernel> /usr/sbin/sshd /bin/bash"
 391  * will cause "/bin/pwd" executed from "<kernel> /usr/sbin/sshd /bin/bash"
 392  * domain to remain in "<kernel> /usr/sbin/sshd /bin/bash" domain.
 393  *
 394  * You may add "no_" prefix to "keep_domain".
 395  * "keep_domain <kernel> /usr/sbin/sshd /bin/bash" and
 396  * "no_keep_domain /usr/bin/passwd from <kernel> /usr/sbin/sshd /bin/bash" will
 397  * cause "/usr/bin/passwd" to belong to
 398  * "<kernel> /usr/sbin/sshd /bin/bash /usr/bin/passwd" domain, unless
 399  * explicitly specified by "initialize_domain".
 400  */
 401 static LIST_HEAD(tomoyo_domain_keeper_list);
 402
 403 /**
 404  * tomoyo_update_domain_keeper_entry - Update "struct tomoyo_domain_keeper_entry" list.
 405  *
 406  * @domainname: The name of domain.
 407  * @program:    The name of program. May be NULL.
 408  * @is_not:     True if it is "no_keep_domain" entry.
 409  * @is_delete:  True if it is a delete request.
 410  *
 411  * Returns 0 on success, negative value otherwise.
 412  *
 413  * Caller holds tomoyo_read_lock().
 414  */
 415 static int tomoyo_update_domain_keeper_entry(const char *domainname,
 416                                              const char *program,
 417                                              const bool is_not,
 418                                              const bool is_delete)
 419 {
 420         struct tomoyo_domain_keeper_entry *entry = NULL;
 421         struct tomoyo_domain_keeper_entry *ptr;
 422         const struct tomoyo_path_info *saved_domainname;
 423         const struct tomoyo_path_info *saved_program = NULL;
 424         int error = is_delete ? -ENOENT : -ENOMEM;
 425         bool is_last_name = false;
 426
 427         if (!tomoyo_is_domain_def(domainname) &&
 428             tomoyo_is_correct_path(domainname, 1, -1, -1, __func__))
 429                 is_last_name = true;
 430         else if (!tomoyo_is_correct_domain(domainname, __func__))
 431                 return -EINVAL;
 432         if (program) {
 433                 if (!tomoyo_is_correct_path(program, 1, -1, -1, __func__))
 434                         return -EINVAL;
 435                 saved_program = tomoyo_save_name(program);
 436                 if (!saved_program)
 437                         goto out;
 438         }
 439         saved_domainname = tomoyo_save_name(domainname);
 440         if (!saved_domainname)
 441                 goto out;
 442         if (!is_delete)
 443                 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
 444         mutex_lock(&tomoyo_policy_lock);
 445         list_for_each_entry_rcu(ptr, &tomoyo_domain_keeper_list, list) {
 446                 if (ptr->is_not != is_not ||
 447                     ptr->domainname != saved_domainname ||
 448                     ptr->program != saved_program)
 449                         continue;
 450                 ptr->is_deleted = is_delete;
 451                 error = 0;
 452                 break;
 453         }
 454         if (!is_delete && error && tomoyo_memory_ok(entry)) {
 455                 entry->domainname = saved_domainname;
 456                 entry->program = saved_program;
 457                 entry->is_not = is_not;
 458                 entry->is_last_name = is_last_name;
 459                 list_add_tail_rcu(&entry->list, &tomoyo_domain_keeper_list);
 460                 entry = NULL;
 461                 error = 0;
 462         }
 463         mutex_unlock(&tomoyo_policy_lock);
 464  out:
 465         kfree(entry);
 466         return error;
 467 }
 468
 469 /**
 470  * tomoyo_write_domain_keeper_policy - Write "struct tomoyo_domain_keeper_entry" list.
 471  *
 472  * @data:      String to parse.
 473  * @is_not:    True if it is "no_keep_domain" entry.
 474  * @is_delete: True if it is a delete request.
 475  *
 476  * Caller holds tomoyo_read_lock().
 477  */
 478 int tomoyo_write_domain_keeper_policy(char *data, const bool is_not,
 479                                       const bool is_delete)
 480 {
 481         char *cp = strstr(data, " from ");
 482
 483         if (cp) {
 484                 *cp = '\0';
 485                 return tomoyo_update_domain_keeper_entry(cp + 6, data, is_not,
 486                                                          is_delete);
 487         }
 488         return tomoyo_update_domain_keeper_entry(data, NULL, is_not, is_delete);
 489 }
 490
 491 /**
 492  * tomoyo_read_domain_keeper_policy - Read "struct tomoyo_domain_keeper_entry" list.
 493  *
 494  * @head: Pointer to "struct tomoyo_io_buffer".
 495  *
 496  * Returns true on success, false otherwise.
 497  *
 498  * Caller holds tomoyo_read_lock().
 499  */
 500 bool tomoyo_read_domain_keeper_policy(struct tomoyo_io_buffer *head)
 501 {
 502         struct list_head *pos;
 503         bool done = true;
 504
 505         list_for_each_cookie(pos, head->read_var2,
 506                              &tomoyo_domain_keeper_list) {
 507                 struct tomoyo_domain_keeper_entry *ptr;
 508                 const char *no;
 509                 const char *from = "";
 510                 const char *program = "";
 511
 512                 ptr = list_entry(pos, struct tomoyo_domain_keeper_entry, list);
 513                 if (ptr->is_deleted)
 514                         continue;
 515                 no = ptr->is_not ? "no_" : "";
 516                 if (ptr->program) {
 517                         from = " from ";
 518                         program = ptr->program->name;
 519                 }
 520                 done = tomoyo_io_printf(head,
 521                                         "%s" TOMOYO_KEYWORD_KEEP_DOMAIN
 522                                         "%s%s%s\n", no, program, from,
 523                                         ptr->domainname->name);
 524                 if (!done)
 525                         break;
 526         }
 527         return done;
 528 }
 529
 530 /**
 531  * tomoyo_is_domain_keeper - Check whether the given program causes domain transition suppression.
 532  *
 533  * @domainname: The name of domain.
 534  * @program:    The name of program.
 535  * @last_name:  The last component of @domainname.
 536  *
 537  * Returns true if executing @program supresses domain transition,
 538  * false otherwise.
 539  *
 540  * Caller holds tomoyo_read_lock().
 541  */
 542 static bool tomoyo_is_domain_keeper(const struct tomoyo_path_info *domainname,
 543                                     const struct tomoyo_path_info *program,
 544                                     const struct tomoyo_path_info *last_name)
 545 {
 546         struct tomoyo_domain_keeper_entry *ptr;
 547         bool flag = false;
 548
 549         list_for_each_entry_rcu(ptr, &tomoyo_domain_keeper_list, list) {
 550                 if (ptr->is_deleted)
 551                         continue;
 552                 if (!ptr->is_last_name) {
 553                         if (ptr->domainname != domainname)
 554                                 continue;
 555                 } else {
 556                         if (tomoyo_pathcmp(ptr->domainname, last_name))
 557                                 continue;
 558                 }
 559                 if (ptr->program && tomoyo_pathcmp(ptr->program, program))
 560                         continue;
 561                 if (ptr->is_not) {
 562                         flag = false;
 563                         break;
 564                 }
 565                 flag = true;
 566         }
 567         return flag;
 568 }
 569
 570 /*
 571  * tomoyo_alias_list is used for holding list of symlink's pathnames which are
 572  * allowed to be passed to an execve() request. Normally, the domainname which
 573  * the current process will belong to after execve() succeeds is calculated
 574  * using dereferenced pathnames. But some programs behave differently depending
 575  * on the name passed to argv[0]. For busybox, calculating domainname using
 576  * dereferenced pathnames will cause all programs in the busybox to belong to
 577  * the same domain. Thus, TOMOYO provides a way to allow use of symlink's
 578  * pathname for checking execve()'s permission and calculating domainname which
 579  * the current process will belong to after execve() succeeds.
 580  *
 581  * An entry is added by
 582  *
 583  * # echo 'alias /bin/busybox /bin/cat' > \
 584  *                            /sys/kernel/security/tomoyo/exception_policy
 585  *
 586  * and is deleted by
 587  *
 588  * # echo 'delete alias /bin/busybox /bin/cat' > \
 589  *                            /sys/kernel/security/tomoyo/exception_policy
 590  *
 591  * and all entries are retrieved by
 592  *
 593  * # grep ^alias /sys/kernel/security/tomoyo/exception_policy
 594  *
 595  * In the example above, if /bin/cat is a symlink to /bin/busybox and execution
 596  * of /bin/cat is requested, permission is checked for /bin/cat rather than
 597  * /bin/busybox and domainname which the current process will belong to after
 598  * execve() succeeds is calculated using /bin/cat rather than /bin/busybox .
 599  */
 600 static LIST_HEAD(tomoyo_alias_list);
 601
 602 /**
 603  * tomoyo_update_alias_entry - Update "struct tomoyo_alias_entry" list.
 604  *
 605  * @original_name: The original program's real name.
 606  * @aliased_name:  The symbolic program's symbolic link's name.
 607  * @is_delete:     True if it is a delete request.
 608  *
 609  * Returns 0 on success, negative value otherwise.
 610  *
 611  * Caller holds tomoyo_read_lock().
 612  */
 613 static int tomoyo_update_alias_entry(const char *original_name,
 614                                      const char *aliased_name,
 615                                      const bool is_delete)
 616 {
 617         struct tomoyo_alias_entry *entry = NULL;
 618         struct tomoyo_alias_entry *ptr;
 619         const struct tomoyo_path_info *saved_original_name;
 620         const struct tomoyo_path_info *saved_aliased_name;
 621         int error = is_delete ? -ENOENT : -ENOMEM;
 622
 623         if (!tomoyo_is_correct_path(original_name, 1, -1, -1, __func__) ||
 624             !tomoyo_is_correct_path(aliased_name, 1, -1, -1, __func__))
 625                 return -EINVAL; /* No patterns allowed. */
 626         saved_original_name = tomoyo_save_name(original_name);
 627         saved_aliased_name = tomoyo_save_name(aliased_name);
 628         if (!saved_original_name || !saved_aliased_name)
 629                 goto out;
 630         if (!is_delete)
 631                 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
 632         mutex_lock(&tomoyo_policy_lock);
 633         list_for_each_entry_rcu(ptr, &tomoyo_alias_list, list) {
 634                 if (ptr->original_name != saved_original_name ||
 635                     ptr->aliased_name != saved_aliased_name)
 636                         continue;
 637                 ptr->is_deleted = is_delete;
 638                 error = 0;
 639                 break;
 640         }
 641         if (!is_delete && error && tomoyo_memory_ok(entry)) {
 642                 entry->original_name = saved_original_name;
 643                 entry->aliased_name = saved_aliased_name;
 644                 list_add_tail_rcu(&entry->list, &tomoyo_alias_list);
 645                 entry = NULL;
 646                 error = 0;
 647         }
 648         mutex_unlock(&tomoyo_policy_lock);
 649  out:
 650         kfree(entry);
 651         return error;
 652 }
 653
 654 /**
 655  * tomoyo_read_alias_policy - Read "struct tomoyo_alias_entry" list.
 656  *
 657  * @head: Pointer to "struct tomoyo_io_buffer".
 658  *
 659  * Returns true on success, false otherwise.
 660  *
 661  * Caller holds tomoyo_read_lock().
 662  */
 663 bool tomoyo_read_alias_policy(struct tomoyo_io_buffer *head)
 664 {
 665         struct list_head *pos;
 666         bool done = true;
 667
 668         list_for_each_cookie(pos, head->read_var2, &tomoyo_alias_list) {
 669                 struct tomoyo_alias_entry *ptr;
 670
 671                 ptr = list_entry(pos, struct tomoyo_alias_entry, list);
 672                 if (ptr->is_deleted)
 673                         continue;
 674                 done = tomoyo_io_printf(head, TOMOYO_KEYWORD_ALIAS "%s %s\n",
 675                                         ptr->original_name->name,
 676                                         ptr->aliased_name->name);
 677                 if (!done)
 678                         break;
 679         }
 680         return done;
 681 }
 682
 683 /**
 684  * tomoyo_write_alias_policy - Write "struct tomoyo_alias_entry" list.
 685  *
 686  * @data:      String to parse.
 687  * @is_delete: True if it is a delete request.
 688  *
 689  * Returns 0 on success, negative value otherwise.
 690  *
 691  * Caller holds tomoyo_read_lock().
 692  */
 693 int tomoyo_write_alias_policy(char *data, const bool is_delete)
 694 {
 695         char *cp = strchr(data, ' ');
 696
 697         if (!cp)
 698                 return -EINVAL;
 699         *cp++ = '\0';
 700         return tomoyo_update_alias_entry(data, cp, is_delete);
 701 }
 702
 703 /**
 704  * tomoyo_find_or_assign_new_domain - Create a domain.
 705  *
 706  * @domainname: The name of domain.
 707  * @profile:    Profile number to assign if the domain was newly created.
 708  *
 709  * Returns pointer to "struct tomoyo_domain_info" on success, NULL otherwise.
 710  *
 711  * Caller holds tomoyo_read_lock().
 712  */
 713 struct tomoyo_domain_info *tomoyo_find_or_assign_new_domain(const char *
 714                                                             domainname,
 715                                                             const u8 profile)
 716 {
 717         struct tomoyo_domain_info *entry;
 718         struct tomoyo_domain_info *domain;
 719         const struct tomoyo_path_info *saved_domainname;
 720         bool found = false;
 721
 722         if (!tomoyo_is_correct_domain(domainname, __func__))
 723                 return NULL;
 724         saved_domainname = tomoyo_save_name(domainname);
 725         if (!saved_domainname)
 726                 return NULL;
 727         entry = kzalloc(sizeof(*entry), GFP_KERNEL);
 728         mutex_lock(&tomoyo_policy_lock);
 729         list_for_each_entry_rcu(domain, &tomoyo_domain_list, list) {
 730                 if (domain->is_deleted ||
 731                     tomoyo_pathcmp(saved_domainname, domain->domainname))
 732                         continue;
 733                 found = true;
 734                 break;
 735         }
 736         if (!found && tomoyo_memory_ok(entry)) {
 737                 INIT_LIST_HEAD(&entry->acl_info_list);
 738                 entry->domainname = saved_domainname;
 739                 entry->profile = profile;
 740                 list_add_tail_rcu(&entry->list, &tomoyo_domain_list);
 741                 domain = entry;
 742                 entry = NULL;
 743                 found = true;
 744         }
 745         mutex_unlock(&tomoyo_policy_lock);
 746         kfree(entry);
 747         return found ? domain : NULL;
 748 }
 749
 750 /**
 751  * tomoyo_find_next_domain - Find a domain.
 752  *
 753  * @bprm: Pointer to "struct linux_binprm".
 754  *
 755  * Returns 0 on success, negative value otherwise.
 756  *
 757  * Caller holds tomoyo_read_lock().
 758  */
 759 int tomoyo_find_next_domain(struct linux_binprm *bprm)
 760 {
 761         /*
 762          * This function assumes that the size of buffer returned by
 763          * tomoyo_realpath() = TOMOYO_MAX_PATHNAME_LEN.
 764          */
 765         struct tomoyo_page_buffer *tmp = kzalloc(sizeof(*tmp), GFP_KERNEL);
 766         struct tomoyo_domain_info *old_domain = tomoyo_domain();
 767         struct tomoyo_domain_info *domain = NULL;
 768         const char *old_domain_name = old_domain->domainname->name;
 769         const char *original_name = bprm->filename;
 770         char *new_domain_name = NULL;
 771         char *real_program_name = NULL;
 772         char *symlink_program_name = NULL;
 773         const u8 mode = tomoyo_check_flags(old_domain, TOMOYO_MAC_FOR_FILE);
 774         const bool is_enforce = (mode == 3);
 775         int retval = -ENOMEM;
 776         struct tomoyo_path_info r; /* real name */
 777         struct tomoyo_path_info s; /* symlink name */
 778         struct tomoyo_path_info l; /* last name */
 779         static bool initialized;
 780
 781         if (!tmp)
 782                 goto out;
 783
 784         if (!initialized) {
 785                 /*
 786                  * Built-in initializers. This is needed because policies are
 787                  * not loaded until starting /sbin/init.
 788                  */
 789                 tomoyo_update_domain_initializer_entry(NULL, "/sbin/hotplug",
 790                                                        false, false);
 791                 tomoyo_update_domain_initializer_entry(NULL, "/sbin/modprobe",
 792                                                        false, false);
 793                 initialized = true;
 794         }
 795
 796         /* Get tomoyo_realpath of program. */
 797         retval = -ENOENT;
 798         /* I hope tomoyo_realpath() won't fail with -ENOMEM. */
 799         real_program_name = tomoyo_realpath(original_name);
 800         if (!real_program_name)
 801                 goto out;
 802         /* Get tomoyo_realpath of symbolic link. */
 803         symlink_program_name = tomoyo_realpath_nofollow(original_name);
 804         if (!symlink_program_name)
 805                 goto out;
 806
 807         r.name = real_program_name;
 808         tomoyo_fill_path_info(&r);
 809         s.name = symlink_program_name;
 810         tomoyo_fill_path_info(&s);
 811         l.name = tomoyo_get_last_name(old_domain);
 812         tomoyo_fill_path_info(&l);
 813
 814         /* Check 'alias' directive. */
 815         if (tomoyo_pathcmp(&r, &s)) {
 816                 struct tomoyo_alias_entry *ptr;
 817                 /* Is this program allowed to be called via symbolic links? */
 818                 list_for_each_entry_rcu(ptr, &tomoyo_alias_list, list) {
 819                         if (ptr->is_deleted ||
 820                             tomoyo_pathcmp(&r, ptr->original_name) ||
 821                             tomoyo_pathcmp(&s, ptr->aliased_name))
 822                                 continue;
 823                         memset(real_program_name, 0, TOMOYO_MAX_PATHNAME_LEN);
 824                         strncpy(real_program_name, ptr->aliased_name->name,
 825                                 TOMOYO_MAX_PATHNAME_LEN - 1);
 826                         tomoyo_fill_path_info(&r);
 827                         break;
 828                 }
 829         }
 830
 831         /* Check execute permission. */
 832         retval = tomoyo_check_exec_perm(old_domain, &r);
 833         if (retval < 0)
 834                 goto out;
 835
 836         new_domain_name = tmp->buffer;
 837         if (tomoyo_is_domain_initializer(old_domain->domainname, &r, &l)) {
 838                 /* Transit to the child of tomoyo_kernel_domain domain. */
 839                 snprintf(new_domain_name, TOMOYO_MAX_PATHNAME_LEN + 1,
 840                          TOMOYO_ROOT_NAME " " "%s", real_program_name);
 841         } else if (old_domain == &tomoyo_kernel_domain &&
 842                    !tomoyo_policy_loaded) {
 843                 /*
 844                  * Needn't to transit from kernel domain before starting
 845                  * /sbin/init. But transit from kernel domain if executing
 846                  * initializers because they might start before /sbin/init.
 847                  */
 848                 domain = old_domain;
 849         } else if (tomoyo_is_domain_keeper(old_domain->domainname, &r, &l)) {
 850                 /* Keep current domain. */
 851                 domain = old_domain;
 852         } else {
 853                 /* Normal domain transition. */
 854                 snprintf(new_domain_name, TOMOYO_MAX_PATHNAME_LEN + 1,
 855                          "%s %s", old_domain_name, real_program_name);
 856         }
 857         if (domain || strlen(new_domain_name) >= TOMOYO_MAX_PATHNAME_LEN)
 858                 goto done;
 859         domain = tomoyo_find_domain(new_domain_name);
 860         if (domain)
 861                 goto done;
 862         if (is_enforce)
 863                 goto done;
 864         domain = tomoyo_find_or_assign_new_domain(new_domain_name,
 865                                                   old_domain->profile);
 866  done:
 867         if (domain)
 868                 goto out;
 869         printk(KERN_WARNING "TOMOYO-ERROR: Domain '%s' not defined.\n",
 870                new_domain_name);
 871         if (is_enforce)
 872                 retval = -EPERM;
 873         else
 874                 old_domain->transition_failed = true;
 875  out:
 876         if (!domain)
 877                 domain = old_domain;
 878         bprm->cred->security = domain;
 879         kfree(real_program_name);
 880         kfree(symlink_program_name);
 881         kfree(tmp);
 882         return retval;
 883 }