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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 *new_entry;
 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 = -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                         return -ENOMEM;
 222         }
 223         saved_program = tomoyo_save_name(program);
 224         if (!saved_program)
 225                 return -ENOMEM;
 226         new_entry = kmalloc(sizeof(*new_entry), GFP_KERNEL);
 227         mutex_lock(&tomoyo_policy_lock);
 228         list_for_each_entry_rcu(ptr, &tomoyo_domain_initializer_list, list) {
 229                 if (ptr->is_not != is_not ||
 230                     ptr->domainname != saved_domainname ||
 231                     ptr->program != saved_program)
 232                         continue;
 233                 ptr->is_deleted = is_delete;
 234                 error = 0;
 235                 goto out;
 236         }
 237         if (is_delete) {
 238                 error = -ENOENT;
 239                 goto out;
 240         }
 241         if (!tomoyo_memory_ok(new_entry))
 242                 goto out;
 243         new_entry->domainname = saved_domainname;
 244         new_entry->program = saved_program;
 245         new_entry->is_not = is_not;
 246         new_entry->is_last_name = is_last_name;
 247         list_add_tail_rcu(&new_entry->list, &tomoyo_domain_initializer_list);
 248         new_entry = NULL;
 249         error = 0;
 250  out:
 251         mutex_unlock(&tomoyo_policy_lock);
 252         kfree(new_entry);
 253         return error;
 254 }
 255
 256 /**
 257  * tomoyo_read_domain_initializer_policy - Read "struct tomoyo_domain_initializer_entry" list.
 258  *
 259  * @head: Pointer to "struct tomoyo_io_buffer".
 260  *
 261  * Returns true on success, false otherwise.
 262  *
 263  * Caller holds tomoyo_read_lock().
 264  */
 265 bool tomoyo_read_domain_initializer_policy(struct tomoyo_io_buffer *head)
 266 {
 267         struct list_head *pos;
 268         bool done = true;
 269
 270         list_for_each_cookie(pos, head->read_var2,
 271                              &tomoyo_domain_initializer_list) {
 272                 const char *no;
 273                 const char *from = "";
 274                 const char *domain = "";
 275                 struct tomoyo_domain_initializer_entry *ptr;
 276                 ptr = list_entry(pos, struct tomoyo_domain_initializer_entry,
 277                                   list);
 278                 if (ptr->is_deleted)
 279                         continue;
 280                 no = ptr->is_not ? "no_" : "";
 281                 if (ptr->domainname) {
 282                         from = " from ";
 283                         domain = ptr->domainname->name;
 284                 }
 285                 done = tomoyo_io_printf(head,
 286                                         "%s" TOMOYO_KEYWORD_INITIALIZE_DOMAIN
 287                                         "%s%s%s\n", no, ptr->program->name,
 288                                         from, domain);
 289                 if (!done)
 290                         break;
 291         }
 292         return done;
 293 }
 294
 295 /**
 296  * tomoyo_write_domain_initializer_policy - Write "struct tomoyo_domain_initializer_entry" list.
 297  *
 298  * @data:      String to parse.
 299  * @is_not:    True if it is "no_initialize_domain" entry.
 300  * @is_delete: True if it is a delete request.
 301  *
 302  * Returns 0 on success, negative value otherwise.
 303  *
 304  * Caller holds tomoyo_read_lock().
 305  */
 306 int tomoyo_write_domain_initializer_policy(char *data, const bool is_not,
 307                                            const bool is_delete)
 308 {
 309         char *cp = strstr(data, " from ");
 310
 311         if (cp) {
 312                 *cp = '\0';
 313                 return tomoyo_update_domain_initializer_entry(cp + 6, data,
 314                                                               is_not,
 315                                                               is_delete);
 316         }
 317         return tomoyo_update_domain_initializer_entry(NULL, data, is_not,
 318                                                       is_delete);
 319 }
 320
 321 /**
 322  * tomoyo_is_domain_initializer - Check whether the given program causes domainname reinitialization.
 323  *
 324  * @domainname: The name of domain.
 325  * @program:    The name of program.
 326  * @last_name:  The last component of @domainname.
 327  *
 328  * Returns true if executing @program reinitializes domain transition,
 329  * false otherwise.
 330  *
 331  * Caller holds tomoyo_read_lock().
 332  */
 333 static bool tomoyo_is_domain_initializer(const struct tomoyo_path_info *
 334                                          domainname,
 335                                          const struct tomoyo_path_info *program,
 336                                          const struct tomoyo_path_info *
 337                                          last_name)
 338 {
 339         struct tomoyo_domain_initializer_entry *ptr;
 340         bool flag = false;
 341
 342         list_for_each_entry_rcu(ptr, &tomoyo_domain_initializer_list, list) {
 343                 if (ptr->is_deleted)
 344                         continue;
 345                 if (ptr->domainname) {
 346                         if (!ptr->is_last_name) {
 347                                 if (ptr->domainname != domainname)
 348                                         continue;
 349                         } else {
 350                                 if (tomoyo_pathcmp(ptr->domainname, last_name))
 351                                         continue;
 352                         }
 353                 }
 354                 if (tomoyo_pathcmp(ptr->program, program))
 355                         continue;
 356                 if (ptr->is_not) {
 357                         flag = false;
 358                         break;
 359                 }
 360                 flag = true;
 361         }
 362         return flag;
 363 }
 364
 365 /*
 366  * tomoyo_domain_keeper_list is used for holding list of domainnames which
 367  * suppresses domain transition. Normally, a domainname is monotonically
 368  * getting longer. But sometimes, we want to suppress domain transition.
 369  * It would be convenient for us that programs executed from a login session
 370  * belong to the same domain. Thus, TOMOYO provides a way to suppress domain
 371  * transition.
 372  *
 373  * An entry is added by
 374  *
 375  * # echo 'keep_domain <kernel> /usr/sbin/sshd /bin/bash' > \
 376  *                              /sys/kernel/security/tomoyo/exception_policy
 377  *
 378  * and is deleted by
 379  *
 380  * # echo 'delete keep_domain <kernel> /usr/sbin/sshd /bin/bash' > \
 381  *                              /sys/kernel/security/tomoyo/exception_policy
 382  *
 383  * and all entries are retrieved by
 384  *
 385  * # grep ^keep_domain /sys/kernel/security/tomoyo/exception_policy
 386  *
 387  * In the example above, any process which belongs to
 388  * "<kernel> /usr/sbin/sshd /bin/bash" domain will remain in that domain,
 389  * unless explicitly specified by "initialize_domain" or "no_keep_domain".
 390  *
 391  * You may specify a program using "from" keyword.
 392  * "keep_domain /bin/pwd from <kernel> /usr/sbin/sshd /bin/bash"
 393  * will cause "/bin/pwd" executed from "<kernel> /usr/sbin/sshd /bin/bash"
 394  * domain to remain in "<kernel> /usr/sbin/sshd /bin/bash" domain.
 395  *
 396  * You may add "no_" prefix to "keep_domain".
 397  * "keep_domain <kernel> /usr/sbin/sshd /bin/bash" and
 398  * "no_keep_domain /usr/bin/passwd from <kernel> /usr/sbin/sshd /bin/bash" will
 399  * cause "/usr/bin/passwd" to belong to
 400  * "<kernel> /usr/sbin/sshd /bin/bash /usr/bin/passwd" domain, unless
 401  * explicitly specified by "initialize_domain".
 402  */
 403 static LIST_HEAD(tomoyo_domain_keeper_list);
 404
 405 /**
 406  * tomoyo_update_domain_keeper_entry - Update "struct tomoyo_domain_keeper_entry" list.
 407  *
 408  * @domainname: The name of domain.
 409  * @program:    The name of program. May be NULL.
 410  * @is_not:     True if it is "no_keep_domain" entry.
 411  * @is_delete:  True if it is a delete request.
 412  *
 413  * Returns 0 on success, negative value otherwise.
 414  *
 415  * Caller holds tomoyo_read_lock().
 416  */
 417 static int tomoyo_update_domain_keeper_entry(const char *domainname,
 418                                              const char *program,
 419                                              const bool is_not,
 420                                              const bool is_delete)
 421 {
 422         struct tomoyo_domain_keeper_entry *new_entry;
 423         struct tomoyo_domain_keeper_entry *ptr;
 424         const struct tomoyo_path_info *saved_domainname;
 425         const struct tomoyo_path_info *saved_program = NULL;
 426         int error = -ENOMEM;
 427         bool is_last_name = false;
 428
 429         if (!tomoyo_is_domain_def(domainname) &&
 430             tomoyo_is_correct_path(domainname, 1, -1, -1, __func__))
 431                 is_last_name = true;
 432         else if (!tomoyo_is_correct_domain(domainname, __func__))
 433                 return -EINVAL;
 434         if (program) {
 435                 if (!tomoyo_is_correct_path(program, 1, -1, -1, __func__))
 436                         return -EINVAL;
 437                 saved_program = tomoyo_save_name(program);
 438                 if (!saved_program)
 439                         return -ENOMEM;
 440         }
 441         saved_domainname = tomoyo_save_name(domainname);
 442         if (!saved_domainname)
 443                 return -ENOMEM;
 444         new_entry = kmalloc(sizeof(*new_entry), GFP_KERNEL);
 445         mutex_lock(&tomoyo_policy_lock);
 446         list_for_each_entry_rcu(ptr, &tomoyo_domain_keeper_list, list) {
 447                 if (ptr->is_not != is_not ||
 448                     ptr->domainname != saved_domainname ||
 449                     ptr->program != saved_program)
 450                         continue;
 451                 ptr->is_deleted = is_delete;
 452                 error = 0;
 453                 goto out;
 454         }
 455         if (is_delete) {
 456                 error = -ENOENT;
 457                 goto out;
 458         }
 459         if (!tomoyo_memory_ok(new_entry))
 460                 goto out;
 461         new_entry->domainname = saved_domainname;
 462         new_entry->program = saved_program;
 463         new_entry->is_not = is_not;
 464         new_entry->is_last_name = is_last_name;
 465         list_add_tail_rcu(&new_entry->list, &tomoyo_domain_keeper_list);
 466         new_entry = NULL;
 467         error = 0;
 468  out:
 469         mutex_unlock(&tomoyo_policy_lock);
 470         kfree(new_entry);
 471         return error;
 472 }
 473
 474 /**
 475  * tomoyo_write_domain_keeper_policy - Write "struct tomoyo_domain_keeper_entry" list.
 476  *
 477  * @data:      String to parse.
 478  * @is_not:    True if it is "no_keep_domain" entry.
 479  * @is_delete: True if it is a delete request.
 480  *
 481  * Caller holds tomoyo_read_lock().
 482  */
 483 int tomoyo_write_domain_keeper_policy(char *data, const bool is_not,
 484                                       const bool is_delete)
 485 {
 486         char *cp = strstr(data, " from ");
 487
 488         if (cp) {
 489                 *cp = '\0';
 490                 return tomoyo_update_domain_keeper_entry(cp + 6, data, is_not,
 491                                                          is_delete);
 492         }
 493         return tomoyo_update_domain_keeper_entry(data, NULL, is_not, is_delete);
 494 }
 495
 496 /**
 497  * tomoyo_read_domain_keeper_policy - Read "struct tomoyo_domain_keeper_entry" list.
 498  *
 499  * @head: Pointer to "struct tomoyo_io_buffer".
 500  *
 501  * Returns true on success, false otherwise.
 502  *
 503  * Caller holds tomoyo_read_lock().
 504  */
 505 bool tomoyo_read_domain_keeper_policy(struct tomoyo_io_buffer *head)
 506 {
 507         struct list_head *pos;
 508         bool done = true;
 509
 510         list_for_each_cookie(pos, head->read_var2,
 511                              &tomoyo_domain_keeper_list) {
 512                 struct tomoyo_domain_keeper_entry *ptr;
 513                 const char *no;
 514                 const char *from = "";
 515                 const char *program = "";
 516
 517                 ptr = list_entry(pos, struct tomoyo_domain_keeper_entry, list);
 518                 if (ptr->is_deleted)
 519                         continue;
 520                 no = ptr->is_not ? "no_" : "";
 521                 if (ptr->program) {
 522                         from = " from ";
 523                         program = ptr->program->name;
 524                 }
 525                 done = tomoyo_io_printf(head,
 526                                         "%s" TOMOYO_KEYWORD_KEEP_DOMAIN
 527                                         "%s%s%s\n", no, program, from,
 528                                         ptr->domainname->name);
 529                 if (!done)
 530                         break;
 531         }
 532         return done;
 533 }
 534
 535 /**
 536  * tomoyo_is_domain_keeper - Check whether the given program causes domain transition suppression.
 537  *
 538  * @domainname: The name of domain.
 539  * @program:    The name of program.
 540  * @last_name:  The last component of @domainname.
 541  *
 542  * Returns true if executing @program supresses domain transition,
 543  * false otherwise.
 544  *
 545  * Caller holds tomoyo_read_lock().
 546  */
 547 static bool tomoyo_is_domain_keeper(const struct tomoyo_path_info *domainname,
 548                                     const struct tomoyo_path_info *program,
 549                                     const struct tomoyo_path_info *last_name)
 550 {
 551         struct tomoyo_domain_keeper_entry *ptr;
 552         bool flag = false;
 553
 554         list_for_each_entry_rcu(ptr, &tomoyo_domain_keeper_list, list) {
 555                 if (ptr->is_deleted)
 556                         continue;
 557                 if (!ptr->is_last_name) {
 558                         if (ptr->domainname != domainname)
 559                                 continue;
 560                 } else {
 561                         if (tomoyo_pathcmp(ptr->domainname, last_name))
 562                                 continue;
 563                 }
 564                 if (ptr->program && tomoyo_pathcmp(ptr->program, program))
 565                         continue;
 566                 if (ptr->is_not) {
 567                         flag = false;
 568                         break;
 569                 }
 570                 flag = true;
 571         }
 572         return flag;
 573 }
 574
 575 /*
 576  * tomoyo_alias_list is used for holding list of symlink's pathnames which are
 577  * allowed to be passed to an execve() request. Normally, the domainname which
 578  * the current process will belong to after execve() succeeds is calculated
 579  * using dereferenced pathnames. But some programs behave differently depending
 580  * on the name passed to argv[0]. For busybox, calculating domainname using
 581  * dereferenced pathnames will cause all programs in the busybox to belong to
 582  * the same domain. Thus, TOMOYO provides a way to allow use of symlink's
 583  * pathname for checking execve()'s permission and calculating domainname which
 584  * the current process will belong to after execve() succeeds.
 585  *
 586  * An entry is added by
 587  *
 588  * # echo 'alias /bin/busybox /bin/cat' > \
 589  *                            /sys/kernel/security/tomoyo/exception_policy
 590  *
 591  * and is deleted by
 592  *
 593  * # echo 'delete alias /bin/busybox /bin/cat' > \
 594  *                            /sys/kernel/security/tomoyo/exception_policy
 595  *
 596  * and all entries are retrieved by
 597  *
 598  * # grep ^alias /sys/kernel/security/tomoyo/exception_policy
 599  *
 600  * In the example above, if /bin/cat is a symlink to /bin/busybox and execution
 601  * of /bin/cat is requested, permission is checked for /bin/cat rather than
 602  * /bin/busybox and domainname which the current process will belong to after
 603  * execve() succeeds is calculated using /bin/cat rather than /bin/busybox .
 604  */
 605 static LIST_HEAD(tomoyo_alias_list);
 606
 607 /**
 608  * tomoyo_update_alias_entry - Update "struct tomoyo_alias_entry" list.
 609  *
 610  * @original_name: The original program's real name.
 611  * @aliased_name:  The symbolic program's symbolic link's name.
 612  * @is_delete:     True if it is a delete request.
 613  *
 614  * Returns 0 on success, negative value otherwise.
 615  *
 616  * Caller holds tomoyo_read_lock().
 617  */
 618 static int tomoyo_update_alias_entry(const char *original_name,
 619                                      const char *aliased_name,
 620                                      const bool is_delete)
 621 {
 622         struct tomoyo_alias_entry *new_entry;
 623         struct tomoyo_alias_entry *ptr;
 624         const struct tomoyo_path_info *saved_original_name;
 625         const struct tomoyo_path_info *saved_aliased_name;
 626         int error = -ENOMEM;
 627
 628         if (!tomoyo_is_correct_path(original_name, 1, -1, -1, __func__) ||
 629             !tomoyo_is_correct_path(aliased_name, 1, -1, -1, __func__))
 630                 return -EINVAL; /* No patterns allowed. */
 631         saved_original_name = tomoyo_save_name(original_name);
 632         saved_aliased_name = tomoyo_save_name(aliased_name);
 633         if (!saved_original_name || !saved_aliased_name)
 634                 return -ENOMEM;
 635         new_entry = kmalloc(sizeof(*new_entry), GFP_KERNEL);
 636         mutex_lock(&tomoyo_policy_lock);
 637         list_for_each_entry_rcu(ptr, &tomoyo_alias_list, list) {
 638                 if (ptr->original_name != saved_original_name ||
 639                     ptr->aliased_name != saved_aliased_name)
 640                         continue;
 641                 ptr->is_deleted = is_delete;
 642                 error = 0;
 643                 goto out;
 644         }
 645         if (is_delete) {
 646                 error = -ENOENT;
 647                 goto out;
 648         }
 649         if (!tomoyo_memory_ok(new_entry))
 650                 goto out;
 651         new_entry->original_name = saved_original_name;
 652         new_entry->aliased_name = saved_aliased_name;
 653         list_add_tail_rcu(&new_entry->list, &tomoyo_alias_list);
 654         new_entry = NULL;
 655         error = 0;
 656  out:
 657         mutex_unlock(&tomoyo_policy_lock);
 658         kfree(new_entry);
 659         return error;
 660 }
 661
 662 /**
 663  * tomoyo_read_alias_policy - Read "struct tomoyo_alias_entry" list.
 664  *
 665  * @head: Pointer to "struct tomoyo_io_buffer".
 666  *
 667  * Returns true on success, false otherwise.
 668  *
 669  * Caller holds tomoyo_read_lock().
 670  */
 671 bool tomoyo_read_alias_policy(struct tomoyo_io_buffer *head)
 672 {
 673         struct list_head *pos;
 674         bool done = true;
 675
 676         list_for_each_cookie(pos, head->read_var2, &tomoyo_alias_list) {
 677                 struct tomoyo_alias_entry *ptr;
 678
 679                 ptr = list_entry(pos, struct tomoyo_alias_entry, list);
 680                 if (ptr->is_deleted)
 681                         continue;
 682                 done = tomoyo_io_printf(head, TOMOYO_KEYWORD_ALIAS "%s %s\n",
 683                                         ptr->original_name->name,
 684                                         ptr->aliased_name->name);
 685                 if (!done)
 686                         break;
 687         }
 688         return done;
 689 }
 690
 691 /**
 692  * tomoyo_write_alias_policy - Write "struct tomoyo_alias_entry" list.
 693  *
 694  * @data:      String to parse.
 695  * @is_delete: True if it is a delete request.
 696  *
 697  * Returns 0 on success, negative value otherwise.
 698  *
 699  * Caller holds tomoyo_read_lock().
 700  */
 701 int tomoyo_write_alias_policy(char *data, const bool is_delete)
 702 {
 703         char *cp = strchr(data, ' ');
 704
 705         if (!cp)
 706                 return -EINVAL;
 707         *cp++ = '\0';
 708         return tomoyo_update_alias_entry(data, cp, is_delete);
 709 }
 710
 711 /**
 712  * tomoyo_find_or_assign_new_domain - Create a domain.
 713  *
 714  * @domainname: The name of domain.
 715  * @profile:    Profile number to assign if the domain was newly created.
 716  *
 717  * Returns pointer to "struct tomoyo_domain_info" on success, NULL otherwise.
 718  *
 719  * Caller holds tomoyo_read_lock().
 720  */
 721 struct tomoyo_domain_info *tomoyo_find_or_assign_new_domain(const char *
 722                                                             domainname,
 723                                                             const u8 profile)
 724 {
 725         struct tomoyo_domain_info *domain;
 726         const struct tomoyo_path_info *saved_domainname;
 727
 728         mutex_lock(&tomoyo_policy_lock);
 729         domain = tomoyo_find_domain(domainname);
 730         if (domain)
 731                 goto out;
 732         if (!tomoyo_is_correct_domain(domainname, __func__))
 733                 goto out;
 734         saved_domainname = tomoyo_save_name(domainname);
 735         if (!saved_domainname)
 736                 goto out;
 737         domain = kmalloc(sizeof(*domain), GFP_KERNEL);
 738         if (tomoyo_memory_ok(domain)) {
 739                 INIT_LIST_HEAD(&domain->acl_info_list);
 740                 domain->domainname = saved_domainname;
 741                 domain->profile = profile;
 742                 list_add_tail_rcu(&domain->list, &tomoyo_domain_list);
 743         } else {
 744                 kfree(domain);
 745                 domain = NULL;
 746         }
 747
 748  out:
 749         mutex_unlock(&tomoyo_policy_lock);
 750         return domain;
 751 }
 752
 753 /**
 754  * tomoyo_find_next_domain - Find a domain.
 755  *
 756  * @bprm: Pointer to "struct linux_binprm".
 757  *
 758  * Returns 0 on success, negative value otherwise.
 759  *
 760  * Caller holds tomoyo_read_lock().
 761  */
 762 int tomoyo_find_next_domain(struct linux_binprm *bprm)
 763 {
 764         /*
 765          * This function assumes that the size of buffer returned by
 766          * tomoyo_realpath() = TOMOYO_MAX_PATHNAME_LEN.
 767          */
 768         struct tomoyo_page_buffer *tmp = kzalloc(sizeof(*tmp), GFP_KERNEL);
 769         struct tomoyo_domain_info *old_domain = tomoyo_domain();
 770         struct tomoyo_domain_info *domain = NULL;
 771         const char *old_domain_name = old_domain->domainname->name;
 772         const char *original_name = bprm->filename;
 773         char *new_domain_name = NULL;
 774         char *real_program_name = NULL;
 775         char *symlink_program_name = NULL;
 776         const u8 mode = tomoyo_check_flags(old_domain, TOMOYO_MAC_FOR_FILE);
 777         const bool is_enforce = (mode == 3);
 778         int retval = -ENOMEM;
 779         struct tomoyo_path_info r; /* real name */
 780         struct tomoyo_path_info s; /* symlink name */
 781         struct tomoyo_path_info l; /* last name */
 782         static bool initialized;
 783
 784         if (!tmp)
 785                 goto out;
 786
 787         if (!initialized) {
 788                 /*
 789                  * Built-in initializers. This is needed because policies are
 790                  * not loaded until starting /sbin/init.
 791                  */
 792                 tomoyo_update_domain_initializer_entry(NULL, "/sbin/hotplug",
 793                                                        false, false);
 794                 tomoyo_update_domain_initializer_entry(NULL, "/sbin/modprobe",
 795                                                        false, false);
 796                 initialized = true;
 797         }
 798
 799         /* Get tomoyo_realpath of program. */
 800         retval = -ENOENT;
 801         /* I hope tomoyo_realpath() won't fail with -ENOMEM. */
 802         real_program_name = tomoyo_realpath(original_name);
 803         if (!real_program_name)
 804                 goto out;
 805         /* Get tomoyo_realpath of symbolic link. */
 806         symlink_program_name = tomoyo_realpath_nofollow(original_name);
 807         if (!symlink_program_name)
 808                 goto out;
 809
 810         r.name = real_program_name;
 811         tomoyo_fill_path_info(&r);
 812         s.name = symlink_program_name;
 813         tomoyo_fill_path_info(&s);
 814         l.name = tomoyo_get_last_name(old_domain);
 815         tomoyo_fill_path_info(&l);
 816
 817         /* Check 'alias' directive. */
 818         if (tomoyo_pathcmp(&r, &s)) {
 819                 struct tomoyo_alias_entry *ptr;
 820                 /* Is this program allowed to be called via symbolic links? */
 821                 list_for_each_entry_rcu(ptr, &tomoyo_alias_list, list) {
 822                         if (ptr->is_deleted ||
 823                             tomoyo_pathcmp(&r, ptr->original_name) ||
 824                             tomoyo_pathcmp(&s, ptr->aliased_name))
 825                                 continue;
 826                         memset(real_program_name, 0, TOMOYO_MAX_PATHNAME_LEN);
 827                         strncpy(real_program_name, ptr->aliased_name->name,
 828                                 TOMOYO_MAX_PATHNAME_LEN - 1);
 829                         tomoyo_fill_path_info(&r);
 830                         break;
 831                 }
 832         }
 833
 834         /* Check execute permission. */
 835         retval = tomoyo_check_exec_perm(old_domain, &r);
 836         if (retval < 0)
 837                 goto out;
 838
 839         new_domain_name = tmp->buffer;
 840         if (tomoyo_is_domain_initializer(old_domain->domainname, &r, &l)) {
 841                 /* Transit to the child of tomoyo_kernel_domain domain. */
 842                 snprintf(new_domain_name, TOMOYO_MAX_PATHNAME_LEN + 1,
 843                          TOMOYO_ROOT_NAME " " "%s", real_program_name);
 844         } else if (old_domain == &tomoyo_kernel_domain &&
 845                    !tomoyo_policy_loaded) {
 846                 /*
 847                  * Needn't to transit from kernel domain before starting
 848                  * /sbin/init. But transit from kernel domain if executing
 849                  * initializers because they might start before /sbin/init.
 850                  */
 851                 domain = old_domain;
 852         } else if (tomoyo_is_domain_keeper(old_domain->domainname, &r, &l)) {
 853                 /* Keep current domain. */
 854                 domain = old_domain;
 855         } else {
 856                 /* Normal domain transition. */
 857                 snprintf(new_domain_name, TOMOYO_MAX_PATHNAME_LEN + 1,
 858                          "%s %s", old_domain_name, real_program_name);
 859         }
 860         if (domain || strlen(new_domain_name) >= TOMOYO_MAX_PATHNAME_LEN)
 861                 goto done;
 862         domain = tomoyo_find_domain(new_domain_name);
 863         if (domain)
 864                 goto done;
 865         if (is_enforce)
 866                 goto done;
 867         domain = tomoyo_find_or_assign_new_domain(new_domain_name,
 868                                                   old_domain->profile);
 869  done:
 870         if (domain)
 871                 goto out;
 872         printk(KERN_WARNING "TOMOYO-ERROR: Domain '%s' not defined.\n",
 873                new_domain_name);
 874         if (is_enforce)
 875                 retval = -EPERM;
 876         else
 877                 old_domain->transition_failed = true;
 878  out:
 879         if (!domain)
 880                 domain = old_domain;
 881         bprm->cred->security = domain;
 882         kfree(real_program_name);
 883         kfree(symlink_program_name);
 884         kfree(tmp);
 885         return retval;
 886 }