security/tomoyo/common.c

   1 /*
   2  * security/tomoyo/common.c
   3  *
   4  * Common functions for TOMOYO.
   5  *
   6  * Copyright (C) 2005-2009  NTT DATA CORPORATION
   7  *
   8  * Version: 2.2.0   2009/04/01
   9  *
  10  */
  11
  12 #include <linux/uaccess.h>
  13 #include <linux/slab.h>
  14 #include <linux/security.h>
  15 #include <linux/hardirq.h>
  16 #include "common.h"
  17
  18 /* Lock for protecting policy. */
  19 DEFINE_MUTEX(tomoyo_policy_lock);
  20
  21 /* Has loading policy done? */
  22 bool tomoyo_policy_loaded;
  23
  24 /* String table for functionality that takes 4 modes. */
  25 static const char *tomoyo_mode_4[4] = {
  26         "disabled", "learning", "permissive", "enforcing"
  27 };
  28 /* String table for functionality that takes 2 modes. */
  29 static const char *tomoyo_mode_2[4] = {
  30         "disabled", "enabled", "enabled", "enabled"
  31 };
  32
  33 /*
  34  * tomoyo_control_array is a static data which contains
  35  *
  36  *  (1) functionality name used by /sys/kernel/security/tomoyo/profile .
  37  *  (2) initial values for "struct tomoyo_profile".
  38  *  (3) max values for "struct tomoyo_profile".
  39  */
  40 static struct {
  41         const char *keyword;
  42         unsigned int current_value;
  43         const unsigned int max_value;
  44 } tomoyo_control_array[TOMOYO_MAX_CONTROL_INDEX] = {
  45         [TOMOYO_MAC_FOR_FILE]     = { "MAC_FOR_FILE",        0,       3 },
  46         [TOMOYO_MAX_ACCEPT_ENTRY] = { "MAX_ACCEPT_ENTRY", 2048, INT_MAX },
  47         [TOMOYO_VERBOSE]          = { "TOMOYO_VERBOSE",      1,       1 },
  48 };
  49
  50 /*
  51  * tomoyo_profile is a structure which is used for holding the mode of access
  52  * controls. TOMOYO has 4 modes: disabled, learning, permissive, enforcing.
  53  * An administrator can define up to 256 profiles.
  54  * The ->profile of "struct tomoyo_domain_info" is used for remembering
  55  * the profile's number (0 - 255) assigned to that domain.
  56  */
  57 static struct tomoyo_profile {
  58         unsigned int value[TOMOYO_MAX_CONTROL_INDEX];
  59         const struct tomoyo_path_info *comment;
  60 } *tomoyo_profile_ptr[TOMOYO_MAX_PROFILES];
  61
  62 /* Permit policy management by non-root user? */
  63 static bool tomoyo_manage_by_non_root;
  64
  65 /* Utility functions. */
  66
  67 /* Open operation for /sys/kernel/security/tomoyo/ interface. */
  68 static int tomoyo_open_control(const u8 type, struct file *file);
  69 /* Close /sys/kernel/security/tomoyo/ interface. */
  70 static int tomoyo_close_control(struct file *file);
  71 /* Read operation for /sys/kernel/security/tomoyo/ interface. */
  72 static int tomoyo_read_control(struct file *file, char __user *buffer,
  73                                const int buffer_len);
  74 /* Write operation for /sys/kernel/security/tomoyo/ interface. */
  75 static int tomoyo_write_control(struct file *file, const char __user *buffer,
  76                                 const int buffer_len);
  77
  78 /**
  79  * tomoyo_is_byte_range - Check whether the string isa \ooo style octal value.
  80  *
  81  * @str: Pointer to the string.
  82  *
  83  * Returns true if @str is a \ooo style octal value, false otherwise.
  84  *
  85  * TOMOYO uses \ooo style representation for 0x01 - 0x20 and 0x7F - 0xFF.
  86  * This function verifies that \ooo is in valid range.
  87  */
  88 static inline bool tomoyo_is_byte_range(const char *str)
  89 {
  90         return *str >= '0' && *str++ <= '3' &&
  91                 *str >= '0' && *str++ <= '7' &&
  92                 *str >= '0' && *str <= '7';
  93 }
  94
  95 /**
  96  * tomoyo_is_alphabet_char - Check whether the character is an alphabet.
  97  *
  98  * @c: The character to check.
  99  *
 100  * Returns true if @c is an alphabet character, false otherwise.
 101  */
 102 static inline bool tomoyo_is_alphabet_char(const char c)
 103 {
 104         return (c >= 'A' && c <= 'Z') || (c >= 'a' && c <= 'z');
 105 }
 106
 107 /**
 108  * tomoyo_make_byte - Make byte value from three octal characters.
 109  *
 110  * @c1: The first character.
 111  * @c2: The second character.
 112  * @c3: The third character.
 113  *
 114  * Returns byte value.
 115  */
 116 static inline u8 tomoyo_make_byte(const u8 c1, const u8 c2, const u8 c3)
 117 {
 118         return ((c1 - '0') << 6) + ((c2 - '0') << 3) + (c3 - '0');
 119 }
 120
 121 /**
 122  * tomoyo_str_starts - Check whether the given string starts with the given keyword.
 123  *
 124  * @src:  Pointer to pointer to the string.
 125  * @find: Pointer to the keyword.
 126  *
 127  * Returns true if @src starts with @find, false otherwise.
 128  *
 129  * The @src is updated to point the first character after the @find
 130  * if @src starts with @find.
 131  */
 132 static bool tomoyo_str_starts(char **src, const char *find)
 133 {
 134         const int len = strlen(find);
 135         char *tmp = *src;
 136
 137         if (strncmp(tmp, find, len))
 138                 return false;
 139         tmp += len;
 140         *src = tmp;
 141         return true;
 142 }
 143
 144 /**
 145  * tomoyo_normalize_line - Format string.
 146  *
 147  * @buffer: The line to normalize.
 148  *
 149  * Leading and trailing whitespaces are removed.
 150  * Multiple whitespaces are packed into single space.
 151  *
 152  * Returns nothing.
 153  */
 154 static void tomoyo_normalize_line(unsigned char *buffer)
 155 {
 156         unsigned char *sp = buffer;
 157         unsigned char *dp = buffer;
 158         bool first = true;
 159
 160         while (tomoyo_is_invalid(*sp))
 161                 sp++;
 162         while (*sp) {
 163                 if (!first)
 164                         *dp++ = ' ';
 165                 first = false;
 166                 while (tomoyo_is_valid(*sp))
 167                         *dp++ = *sp++;
 168                 while (tomoyo_is_invalid(*sp))
 169                         sp++;
 170         }
 171         *dp = '\0';
 172 }
 173
 174 /**
 175  * tomoyo_is_correct_path - Validate a pathname.
 176  * @filename:     The pathname to check.
 177  * @start_type:   Should the pathname start with '/'?
 178  *                1 = must / -1 = must not / 0 = don't care
 179  * @pattern_type: Can the pathname contain a wildcard?
 180  *                1 = must / -1 = must not / 0 = don't care
 181  * @end_type:     Should the pathname end with '/'?
 182  *                1 = must / -1 = must not / 0 = don't care
 183  *
 184  * Check whether the given filename follows the naming rules.
 185  * Returns true if @filename follows the naming rules, false otherwise.
 186  */
 187 bool tomoyo_is_correct_path(const char *filename, const s8 start_type,
 188                             const s8 pattern_type, const s8 end_type)
 189 {
 190         const char *const start = filename;
 191         bool in_repetition = false;
 192         bool contains_pattern = false;
 193         unsigned char c;
 194         unsigned char d;
 195         unsigned char e;
 196
 197         if (!filename)
 198                 goto out;
 199         c = *filename;
 200         if (start_type == 1) { /* Must start with '/' */
 201                 if (c != '/')
 202                         goto out;
 203         } else if (start_type == -1) { /* Must not start with '/' */
 204                 if (c == '/')
 205                         goto out;
 206         }
 207         if (c)
 208                 c = *(filename + strlen(filename) - 1);
 209         if (end_type == 1) { /* Must end with '/' */
 210                 if (c != '/')
 211                         goto out;
 212         } else if (end_type == -1) { /* Must not end with '/' */
 213                 if (c == '/')
 214                         goto out;
 215         }
 216         while (1) {
 217                 c = *filename++;
 218                 if (!c)
 219                         break;
 220                 if (c == '\\') {
 221                         c = *filename++;
 222                         switch (c) {
 223                         case '\\':  /* "\\" */
 224                                 continue;
 225                         case '$':   /* "\$" */
 226                         case '+':   /* "\+" */
 227                         case '?':   /* "\?" */
 228                         case '*':   /* "\*" */
 229                         case '@':   /* "\@" */
 230                         case 'x':   /* "\x" */
 231                         case 'X':   /* "\X" */
 232                         case 'a':   /* "\a" */
 233                         case 'A':   /* "\A" */
 234                         case '-':   /* "\-" */
 235                                 if (pattern_type == -1)
 236                                         break; /* Must not contain pattern */
 237                                 contains_pattern = true;
 238                                 continue;
 239                         case '{':   /* "/\{" */
 240                                 if (filename - 3 < start ||
 241                                     *(filename - 3) != '/')
 242                                         break;
 243                                 if (pattern_type == -1)
 244                                         break; /* Must not contain pattern */
 245                                 contains_pattern = true;
 246                                 in_repetition = true;
 247                                 continue;
 248                         case '}':   /* "\}/" */
 249                                 if (*filename != '/')
 250                                         break;
 251                                 if (!in_repetition)
 252                                         break;
 253                                 in_repetition = false;
 254                                 continue;
 255                         case '0':   /* "\ooo" */
 256                         case '1':
 257                         case '2':
 258                         case '3':
 259                                 d = *filename++;
 260                                 if (d < '0' || d > '7')
 261                                         break;
 262                                 e = *filename++;
 263                                 if (e < '0' || e > '7')
 264                                         break;
 265                                 c = tomoyo_make_byte(c, d, e);
 266                                 if (tomoyo_is_invalid(c))
 267                                         continue; /* pattern is not \000 */
 268                         }
 269                         goto out;
 270                 } else if (in_repetition && c == '/') {
 271                         goto out;
 272                 } else if (tomoyo_is_invalid(c)) {
 273                         goto out;
 274                 }
 275         }
 276         if (pattern_type == 1) { /* Must contain pattern */
 277                 if (!contains_pattern)
 278                         goto out;
 279         }
 280         if (in_repetition)
 281                 goto out;
 282         return true;
 283  out:
 284         return false;
 285 }
 286
 287 /**
 288  * tomoyo_is_correct_domain - Check whether the given domainname follows the naming rules.
 289  * @domainname:   The domainname to check.
 290  *
 291  * Returns true if @domainname follows the naming rules, false otherwise.
 292  */
 293 bool tomoyo_is_correct_domain(const unsigned char *domainname)
 294 {
 295         unsigned char c;
 296         unsigned char d;
 297         unsigned char e;
 298
 299         if (!domainname || strncmp(domainname, TOMOYO_ROOT_NAME,
 300                                    TOMOYO_ROOT_NAME_LEN))
 301                 goto out;
 302         domainname += TOMOYO_ROOT_NAME_LEN;
 303         if (!*domainname)
 304                 return true;
 305         do {
 306                 if (*domainname++ != ' ')
 307                         goto out;
 308                 if (*domainname++ != '/')
 309                         goto out;
 310                 while ((c = *domainname) != '\0' && c != ' ') {
 311                         domainname++;
 312                         if (c == '\\') {
 313                                 c = *domainname++;
 314                                 switch ((c)) {
 315                                 case '\\':  /* "\\" */
 316                                         continue;
 317                                 case '0':   /* "\ooo" */
 318                                 case '1':
 319                                 case '2':
 320                                 case '3':
 321                                         d = *domainname++;
 322                                         if (d < '0' || d > '7')
 323                                                 break;
 324                                         e = *domainname++;
 325                                         if (e < '0' || e > '7')
 326                                                 break;
 327                                         c = tomoyo_make_byte(c, d, e);
 328                                         if (tomoyo_is_invalid(c))
 329                                                 /* pattern is not \000 */
 330                                                 continue;
 331                                 }
 332                                 goto out;
 333                         } else if (tomoyo_is_invalid(c)) {
 334                                 goto out;
 335                         }
 336                 }
 337         } while (*domainname);
 338         return true;
 339  out:
 340         return false;
 341 }
 342
 343 /**
 344  * tomoyo_is_domain_def - Check whether the given token can be a domainname.
 345  *
 346  * @buffer: The token to check.
 347  *
 348  * Returns true if @buffer possibly be a domainname, false otherwise.
 349  */
 350 bool tomoyo_is_domain_def(const unsigned char *buffer)
 351 {
 352         return !strncmp(buffer, TOMOYO_ROOT_NAME, TOMOYO_ROOT_NAME_LEN);
 353 }
 354
 355 /**
 356  * tomoyo_find_domain - Find a domain by the given name.
 357  *
 358  * @domainname: The domainname to find.
 359  *
 360  * Returns pointer to "struct tomoyo_domain_info" if found, NULL otherwise.
 361  *
 362  * Caller holds tomoyo_read_lock().
 363  */
 364 struct tomoyo_domain_info *tomoyo_find_domain(const char *domainname)
 365 {
 366         struct tomoyo_domain_info *domain;
 367         struct tomoyo_path_info name;
 368
 369         name.name = domainname;
 370         tomoyo_fill_path_info(&name);
 371         list_for_each_entry_rcu(domain, &tomoyo_domain_list, list) {
 372                 if (!domain->is_deleted &&
 373                     !tomoyo_pathcmp(&name, domain->domainname))
 374                         return domain;
 375         }
 376         return NULL;
 377 }
 378
 379 /**
 380  * tomoyo_const_part_length - Evaluate the initial length without a pattern in a token.
 381  *
 382  * @filename: The string to evaluate.
 383  *
 384  * Returns the initial length without a pattern in @filename.
 385  */
 386 static int tomoyo_const_part_length(const char *filename)
 387 {
 388         char c;
 389         int len = 0;
 390
 391         if (!filename)
 392                 return 0;
 393         while ((c = *filename++) != '\0') {
 394                 if (c != '\\') {
 395                         len++;
 396                         continue;
 397                 }
 398                 c = *filename++;
 399                 switch (c) {
 400                 case '\\':  /* "\\" */
 401                         len += 2;
 402                         continue;
 403                 case '0':   /* "\ooo" */
 404                 case '1':
 405                 case '2':
 406                 case '3':
 407                         c = *filename++;
 408                         if (c < '0' || c > '7')
 409                                 break;
 410                         c = *filename++;
 411                         if (c < '0' || c > '7')
 412                                 break;
 413                         len += 4;
 414                         continue;
 415                 }
 416                 break;
 417         }
 418         return len;
 419 }
 420
 421 /**
 422  * tomoyo_fill_path_info - Fill in "struct tomoyo_path_info" members.
 423  *
 424  * @ptr: Pointer to "struct tomoyo_path_info" to fill in.
 425  *
 426  * The caller sets "struct tomoyo_path_info"->name.
 427  */
 428 void tomoyo_fill_path_info(struct tomoyo_path_info *ptr)
 429 {
 430         const char *name = ptr->name;
 431         const int len = strlen(name);
 432
 433         ptr->const_len = tomoyo_const_part_length(name);
 434         ptr->is_dir = len && (name[len - 1] == '/');
 435         ptr->is_patterned = (ptr->const_len < len);
 436         ptr->hash = full_name_hash(name, len);
 437 }
 438
 439 /**
 440  * tomoyo_file_matches_pattern2 - Pattern matching without '/' character
 441  * and "\-" pattern.
 442  *
 443  * @filename:     The start of string to check.
 444  * @filename_end: The end of string to check.
 445  * @pattern:      The start of pattern to compare.
 446  * @pattern_end:  The end of pattern to compare.
 447  *
 448  * Returns true if @filename matches @pattern, false otherwise.
 449  */
 450 static bool tomoyo_file_matches_pattern2(const char *filename,
 451                                          const char *filename_end,
 452                                          const char *pattern,
 453                                          const char *pattern_end)
 454 {
 455         while (filename < filename_end && pattern < pattern_end) {
 456                 char c;
 457                 if (*pattern != '\\') {
 458                         if (*filename++ != *pattern++)
 459                                 return false;
 460                         continue;
 461                 }
 462                 c = *filename;
 463                 pattern++;
 464                 switch (*pattern) {
 465                         int i;
 466                         int j;
 467                 case '?':
 468                         if (c == '/') {
 469                                 return false;
 470                         } else if (c == '\\') {
 471                                 if (filename[1] == '\\')
 472                                         filename++;
 473                                 else if (tomoyo_is_byte_range(filename + 1))
 474                                         filename += 3;
 475                                 else
 476                                         return false;
 477                         }
 478                         break;
 479                 case '\\':
 480                         if (c != '\\')
 481                                 return false;
 482                         if (*++filename != '\\')
 483                                 return false;
 484                         break;
 485                 case '+':
 486                         if (!isdigit(c))
 487                                 return false;
 488                         break;
 489                 case 'x':
 490                         if (!isxdigit(c))
 491                                 return false;
 492                         break;
 493                 case 'a':
 494                         if (!tomoyo_is_alphabet_char(c))
 495                                 return false;
 496                         break;
 497                 case '0':
 498                 case '1':
 499                 case '2':
 500                 case '3':
 501                         if (c == '\\' && tomoyo_is_byte_range(filename + 1)
 502                             && strncmp(filename + 1, pattern, 3) == 0) {
 503                                 filename += 3;
 504                                 pattern += 2;
 505                                 break;
 506                         }
 507                         return false; /* Not matched. */
 508                 case '*':
 509                 case '@':
 510                         for (i = 0; i <= filename_end - filename; i++) {
 511                                 if (tomoyo_file_matches_pattern2(
 512                                                     filename + i, filename_end,
 513                                                     pattern + 1, pattern_end))
 514                                         return true;
 515                                 c = filename[i];
 516                                 if (c == '.' && *pattern == '@')
 517                                         break;
 518                                 if (c != '\\')
 519                                         continue;
 520                                 if (filename[i + 1] == '\\')
 521                                         i++;
 522                                 else if (tomoyo_is_byte_range(filename + i + 1))
 523                                         i += 3;
 524                                 else
 525                                         break; /* Bad pattern. */
 526                         }
 527                         return false; /* Not matched. */
 528                 default:
 529                         j = 0;
 530                         c = *pattern;
 531                         if (c == '$') {
 532                                 while (isdigit(filename[j]))
 533                                         j++;
 534                         } else if (c == 'X') {
 535                                 while (isxdigit(filename[j]))
 536                                         j++;
 537                         } else if (c == 'A') {
 538                                 while (tomoyo_is_alphabet_char(filename[j]))
 539                                         j++;
 540                         }
 541                         for (i = 1; i <= j; i++) {
 542                                 if (tomoyo_file_matches_pattern2(
 543                                                     filename + i, filename_end,
 544                                                     pattern + 1, pattern_end))
 545                                         return true;
 546                         }
 547                         return false; /* Not matched or bad pattern. */
 548                 }
 549                 filename++;
 550                 pattern++;
 551         }
 552         while (*pattern == '\\' &&
 553                (*(pattern + 1) == '*' || *(pattern + 1) == '@'))
 554                 pattern += 2;
 555         return filename == filename_end && pattern == pattern_end;
 556 }
 557
 558 /**
 559  * tomoyo_file_matches_pattern - Pattern matching without without '/' character.
 560  *
 561  * @filename:     The start of string to check.
 562  * @filename_end: The end of string to check.
 563  * @pattern:      The start of pattern to compare.
 564  * @pattern_end:  The end of pattern to compare.
 565  *
 566  * Returns true if @filename matches @pattern, false otherwise.
 567  */
 568 static bool tomoyo_file_matches_pattern(const char *filename,
 569                                            const char *filename_end,
 570                                            const char *pattern,
 571                                            const char *pattern_end)
 572 {
 573         const char *pattern_start = pattern;
 574         bool first = true;
 575         bool result;
 576
 577         while (pattern < pattern_end - 1) {
 578                 /* Split at "\-" pattern. */
 579                 if (*pattern++ != '\\' || *pattern++ != '-')
 580                         continue;
 581                 result = tomoyo_file_matches_pattern2(filename,
 582                                                       filename_end,
 583                                                       pattern_start,
 584                                                       pattern - 2);
 585                 if (first)
 586                         result = !result;
 587                 if (result)
 588                         return false;
 589                 first = false;
 590                 pattern_start = pattern;
 591         }
 592         result = tomoyo_file_matches_pattern2(filename, filename_end,
 593                                               pattern_start, pattern_end);
 594         return first ? result : !result;
 595 }
 596
 597 /**
 598  * tomoyo_path_matches_pattern2 - Do pathname pattern matching.
 599  *
 600  * @f: The start of string to check.
 601  * @p: The start of pattern to compare.
 602  *
 603  * Returns true if @f matches @p, false otherwise.
 604  */
 605 static bool tomoyo_path_matches_pattern2(const char *f, const char *p)
 606 {
 607         const char *f_delimiter;
 608         const char *p_delimiter;
 609
 610         while (*f && *p) {
 611                 f_delimiter = strchr(f, '/');
 612                 if (!f_delimiter)
 613                         f_delimiter = f + strlen(f);
 614                 p_delimiter = strchr(p, '/');
 615                 if (!p_delimiter)
 616                         p_delimiter = p + strlen(p);
 617                 if (*p == '\\' && *(p + 1) == '{')
 618                         goto recursive;
 619                 if (!tomoyo_file_matches_pattern(f, f_delimiter, p,
 620                                                  p_delimiter))
 621                         return false;
 622                 f = f_delimiter;
 623                 if (*f)
 624                         f++;
 625                 p = p_delimiter;
 626                 if (*p)
 627                         p++;
 628         }
 629         /* Ignore trailing "\*" and "\@" in @pattern. */
 630         while (*p == '\\' &&
 631                (*(p + 1) == '*' || *(p + 1) == '@'))
 632                 p += 2;
 633         return !*f && !*p;
 634  recursive:
 635         /*
 636          * The "\{" pattern is permitted only after '/' character.
 637          * This guarantees that below "*(p - 1)" is safe.
 638          * Also, the "\}" pattern is permitted only before '/' character
 639          * so that "\{" + "\}" pair will not break the "\-" operator.
 640          */
 641         if (*(p - 1) != '/' || p_delimiter <= p + 3 || *p_delimiter != '/' ||
 642             *(p_delimiter - 1) != '}' || *(p_delimiter - 2) != '\\')
 643                 return false; /* Bad pattern. */
 644         do {
 645                 /* Compare current component with pattern. */
 646                 if (!tomoyo_file_matches_pattern(f, f_delimiter, p + 2,
 647                                                  p_delimiter - 2))
 648                         break;
 649                 /* Proceed to next component. */
 650                 f = f_delimiter;
 651                 if (!*f)
 652                         break;
 653                 f++;
 654                 /* Continue comparison. */
 655                 if (tomoyo_path_matches_pattern2(f, p_delimiter + 1))
 656                         return true;
 657                 f_delimiter = strchr(f, '/');
 658         } while (f_delimiter);
 659         return false; /* Not matched. */
 660 }
 661
 662 /**
 663  * tomoyo_path_matches_pattern - Check whether the given filename matches the given pattern.
 664  *
 665  * @filename: The filename to check.
 666  * @pattern:  The pattern to compare.
 667  *
 668  * Returns true if matches, false otherwise.
 669  *
 670  * The following patterns are available.
 671  *   \\     \ itself.
 672  *   \ooo   Octal representation of a byte.
 673  *   \*     Zero or more repetitions of characters other than '/'.
 674  *   \@     Zero or more repetitions of characters other than '/' or '.'.
 675  *   \?     1 byte character other than '/'.
 676  *   \$     One or more repetitions of decimal digits.
 677  *   \+     1 decimal digit.
 678  *   \X     One or more repetitions of hexadecimal digits.
 679  *   \x     1 hexadecimal digit.
 680  *   \A     One or more repetitions of alphabet characters.
 681  *   \a     1 alphabet character.
 682  *
 683  *   \-     Subtraction operator.
 684  *
 685  *   /\{dir\}/   '/' + 'One or more repetitions of dir/' (e.g. /dir/ /dir/dir/
 686  *               /dir/dir/dir/ ).
 687  */
 688 bool tomoyo_path_matches_pattern(const struct tomoyo_path_info *filename,
 689                                  const struct tomoyo_path_info *pattern)
 690 {
 691         const char *f = filename->name;
 692         const char *p = pattern->name;
 693         const int len = pattern->const_len;
 694
 695         /* If @pattern doesn't contain pattern, I can use strcmp(). */
 696         if (!pattern->is_patterned)
 697                 return !tomoyo_pathcmp(filename, pattern);
 698         /* Don't compare directory and non-directory. */
 699         if (filename->is_dir != pattern->is_dir)
 700                 return false;
 701         /* Compare the initial length without patterns. */
 702         if (strncmp(f, p, len))
 703                 return false;
 704         f += len;
 705         p += len;
 706         return tomoyo_path_matches_pattern2(f, p);
 707 }
 708
 709 /**
 710  * tomoyo_io_printf - Transactional printf() to "struct tomoyo_io_buffer" structure.
 711  *
 712  * @head: Pointer to "struct tomoyo_io_buffer".
 713  * @fmt:  The printf()'s format string, followed by parameters.
 714  *
 715  * Returns true if output was written, false otherwise.
 716  *
 717  * The snprintf() will truncate, but tomoyo_io_printf() won't.
 718  */
 719 bool tomoyo_io_printf(struct tomoyo_io_buffer *head, const char *fmt, ...)
 720 {
 721         va_list args;
 722         int len;
 723         int pos = head->read_avail;
 724         int size = head->readbuf_size - pos;
 725
 726         if (size <= 0)
 727                 return false;
 728         va_start(args, fmt);
 729         len = vsnprintf(head->read_buf + pos, size, fmt, args);
 730         va_end(args);
 731         if (pos + len >= head->readbuf_size)
 732                 return false;
 733         head->read_avail += len;
 734         return true;
 735 }
 736
 737 /**
 738  * tomoyo_get_exe - Get tomoyo_realpath() of current process.
 739  *
 740  * Returns the tomoyo_realpath() of current process on success, NULL otherwise.
 741  *
 742  * This function uses kzalloc(), so the caller must call kfree()
 743  * if this function didn't return NULL.
 744  */
 745 static const char *tomoyo_get_exe(void)
 746 {
 747         struct mm_struct *mm = current->mm;
 748         struct vm_area_struct *vma;
 749         const char *cp = NULL;
 750
 751         if (!mm)
 752                 return NULL;
 753         down_read(&mm->mmap_sem);
 754         for (vma = mm->mmap; vma; vma = vma->vm_next) {
 755                 if ((vma->vm_flags & VM_EXECUTABLE) && vma->vm_file) {
 756                         cp = tomoyo_realpath_from_path(&vma->vm_file->f_path);
 757                         break;
 758                 }
 759         }
 760         up_read(&mm->mmap_sem);
 761         return cp;
 762 }
 763
 764 /**
 765  * tomoyo_get_msg - Get warning message.
 766  *
 767  * @is_enforce: Is it enforcing mode?
 768  *
 769  * Returns "ERROR" or "WARNING".
 770  */
 771 const char *tomoyo_get_msg(const bool is_enforce)
 772 {
 773         if (is_enforce)
 774                 return "ERROR";
 775         else
 776                 return "WARNING";
 777 }
 778
 779 /**
 780  * tomoyo_check_flags - Check mode for specified functionality.
 781  *
 782  * @domain: Pointer to "struct tomoyo_domain_info".
 783  * @index:  The functionality to check mode.
 784  *
 785  * TOMOYO checks only process context.
 786  * This code disables TOMOYO's enforcement in case the function is called from
 787  * interrupt context.
 788  */
 789 unsigned int tomoyo_check_flags(const struct tomoyo_domain_info *domain,
 790                                 const u8 index)
 791 {
 792         const u8 profile = domain->profile;
 793
 794         if (WARN_ON(in_interrupt()))
 795                 return 0;
 796         return tomoyo_policy_loaded && index < TOMOYO_MAX_CONTROL_INDEX
 797 #if TOMOYO_MAX_PROFILES != 256
 798                 && profile < TOMOYO_MAX_PROFILES
 799 #endif
 800                 && tomoyo_profile_ptr[profile] ?
 801                 tomoyo_profile_ptr[profile]->value[index] : 0;
 802 }
 803
 804 /**
 805  * tomoyo_verbose_mode - Check whether TOMOYO is verbose mode.
 806  *
 807  * @domain: Pointer to "struct tomoyo_domain_info".
 808  *
 809  * Returns true if domain policy violation warning should be printed to
 810  * console.
 811  */
 812 bool tomoyo_verbose_mode(const struct tomoyo_domain_info *domain)
 813 {
 814         return tomoyo_check_flags(domain, TOMOYO_VERBOSE) != 0;
 815 }
 816
 817 /**
 818  * tomoyo_domain_quota_is_ok - Check for domain's quota.
 819  *
 820  * @domain: Pointer to "struct tomoyo_domain_info".
 821  *
 822  * Returns true if the domain is not exceeded quota, false otherwise.
 823  *
 824  * Caller holds tomoyo_read_lock().
 825  */
 826 bool tomoyo_domain_quota_is_ok(struct tomoyo_domain_info * const domain)
 827 {
 828         unsigned int count = 0;
 829         struct tomoyo_acl_info *ptr;
 830
 831         if (!domain)
 832                 return true;
 833         list_for_each_entry_rcu(ptr, &domain->acl_info_list, list) {
 834                 switch (ptr->type) {
 835                         struct tomoyo_path_acl *acl;
 836                         u32 perm;
 837                         u8 i;
 838                 case TOMOYO_TYPE_PATH_ACL:
 839                         acl = container_of(ptr, struct tomoyo_path_acl, head);
 840                         perm = acl->perm | (((u32) acl->perm_high) << 16);
 841                         for (i = 0; i < TOMOYO_MAX_PATH_OPERATION; i++)
 842                                 if (perm & (1 << i))
 843                                         count++;
 844                         if (perm & (1 << TOMOYO_TYPE_READ_WRITE))
 845                                 count -= 2;
 846                         break;
 847                 case TOMOYO_TYPE_PATH2_ACL:
 848                         perm = container_of(ptr, struct tomoyo_path2_acl, head)
 849                                 ->perm;
 850                         for (i = 0; i < TOMOYO_MAX_PATH2_OPERATION; i++)
 851                                 if (perm & (1 << i))
 852                                         count++;
 853                         break;
 854                 }
 855         }
 856         if (count < tomoyo_check_flags(domain, TOMOYO_MAX_ACCEPT_ENTRY))
 857                 return true;
 858         if (!domain->quota_warned) {
 859                 domain->quota_warned = true;
 860                 printk(KERN_WARNING "TOMOYO-WARNING: "
 861                        "Domain '%s' has so many ACLs to hold. "
 862                        "Stopped learning mode.\n", domain->domainname->name);
 863         }
 864         return false;
 865 }
 866
 867 /**
 868  * tomoyo_find_or_assign_new_profile - Create a new profile.
 869  *
 870  * @profile: Profile number to create.
 871  *
 872  * Returns pointer to "struct tomoyo_profile" on success, NULL otherwise.
 873  */
 874 static struct tomoyo_profile *tomoyo_find_or_assign_new_profile(const unsigned
 875                                                                 int profile)
 876 {
 877         static DEFINE_MUTEX(lock);
 878         struct tomoyo_profile *ptr = NULL;
 879         int i;
 880
 881         if (profile >= TOMOYO_MAX_PROFILES)
 882                 return NULL;
 883         mutex_lock(&lock);
 884         ptr = tomoyo_profile_ptr[profile];
 885         if (ptr)
 886                 goto ok;
 887         ptr = kmalloc(sizeof(*ptr), GFP_NOFS);
 888         if (!tomoyo_memory_ok(ptr)) {
 889                 kfree(ptr);
 890                 ptr = NULL;
 891                 goto ok;
 892         }
 893         for (i = 0; i < TOMOYO_MAX_CONTROL_INDEX; i++)
 894                 ptr->value[i] = tomoyo_control_array[i].current_value;
 895         mb(); /* Avoid out-of-order execution. */
 896         tomoyo_profile_ptr[profile] = ptr;
 897  ok:
 898         mutex_unlock(&lock);
 899         return ptr;
 900 }
 901
 902 /**
 903  * tomoyo_write_profile - Write to profile table.
 904  *
 905  * @head: Pointer to "struct tomoyo_io_buffer".
 906  *
 907  * Returns 0 on success, negative value otherwise.
 908  */
 909 static int tomoyo_write_profile(struct tomoyo_io_buffer *head)
 910 {
 911         char *data = head->write_buf;
 912         unsigned int i;
 913         unsigned int value;
 914         char *cp;
 915         struct tomoyo_profile *profile;
 916         unsigned long num;
 917
 918         cp = strchr(data, '-');
 919         if (cp)
 920                 *cp = '\0';
 921         if (strict_strtoul(data, 10, &num))
 922                 return -EINVAL;
 923         if (cp)
 924                 data = cp + 1;
 925         profile = tomoyo_find_or_assign_new_profile(num);
 926         if (!profile)
 927                 return -EINVAL;
 928         cp = strchr(data, '=');
 929         if (!cp)
 930                 return -EINVAL;
 931         *cp = '\0';
 932         if (!strcmp(data, "COMMENT")) {
 933                 const struct tomoyo_path_info *old_comment = profile->comment;
 934                 profile->comment = tomoyo_get_name(cp + 1);
 935                 tomoyo_put_name(old_comment);
 936                 return 0;
 937         }
 938         for (i = 0; i < TOMOYO_MAX_CONTROL_INDEX; i++) {
 939                 if (strcmp(data, tomoyo_control_array[i].keyword))
 940                         continue;
 941                 if (sscanf(cp + 1, "%u", &value) != 1) {
 942                         int j;
 943                         const char **modes;
 944                         switch (i) {
 945                         case TOMOYO_VERBOSE:
 946                                 modes = tomoyo_mode_2;
 947                                 break;
 948                         default:
 949                                 modes = tomoyo_mode_4;
 950                                 break;
 951                         }
 952                         for (j = 0; j < 4; j++) {
 953                                 if (strcmp(cp + 1, modes[j]))
 954                                         continue;
 955                                 value = j;
 956                                 break;
 957                         }
 958                         if (j == 4)
 959                                 return -EINVAL;
 960                 } else if (value > tomoyo_control_array[i].max_value) {
 961                         value = tomoyo_control_array[i].max_value;
 962                 }
 963                 profile->value[i] = value;
 964                 return 0;
 965         }
 966         return -EINVAL;
 967 }
 968
 969 /**
 970  * tomoyo_read_profile - Read from profile table.
 971  *
 972  * @head: Pointer to "struct tomoyo_io_buffer".
 973  *
 974  * Returns 0.
 975  */
 976 static int tomoyo_read_profile(struct tomoyo_io_buffer *head)
 977 {
 978         static const int total = TOMOYO_MAX_CONTROL_INDEX + 1;
 979         int step;
 980
 981         if (head->read_eof)
 982                 return 0;
 983         for (step = head->read_step; step < TOMOYO_MAX_PROFILES * total;
 984              step++) {
 985                 const u8 index = step / total;
 986                 u8 type = step % total;
 987                 const struct tomoyo_profile *profile
 988                         = tomoyo_profile_ptr[index];
 989                 head->read_step = step;
 990                 if (!profile)
 991                         continue;
 992                 if (!type) { /* Print profile' comment tag. */
 993                         if (!tomoyo_io_printf(head, "%u-COMMENT=%s\n",
 994                                               index, profile->comment ?
 995                                               profile->comment->name : ""))
 996                                 break;
 997                         continue;
 998                 }
 999                 type--;
1000                 if (type < TOMOYO_MAX_CONTROL_INDEX) {
1001                         const unsigned int value = profile->value[type];
1002                         const char **modes = NULL;
1003                         const char *keyword
1004                                 = tomoyo_control_array[type].keyword;
1005                         switch (tomoyo_control_array[type].max_value) {
1006                         case 3:
1007                                 modes = tomoyo_mode_4;
1008                                 break;
1009                         case 1:
1010                                 modes = tomoyo_mode_2;
1011                                 break;
1012                         }
1013                         if (modes) {
1014                                 if (!tomoyo_io_printf(head, "%u-%s=%s\n", index,
1015                                                       keyword, modes[value]))
1016                                         break;
1017                         } else {
1018                                 if (!tomoyo_io_printf(head, "%u-%s=%u\n", index,
1019                                                       keyword, value))
1020                                         break;
1021                         }
1022                 }
1023         }
1024         if (step == TOMOYO_MAX_PROFILES * total)
1025                 head->read_eof = true;
1026         return 0;
1027 }
1028
1029 /*
1030  * tomoyo_policy_manager_list is used for holding list of domainnames or
1031  * programs which are permitted to modify configuration via
1032  * /sys/kernel/security/tomoyo/ interface.
1033  *
1034  * An entry is added by
1035  *
1036  * # echo '<kernel> /sbin/mingetty /bin/login /bin/bash' > \
1037  *                                        /sys/kernel/security/tomoyo/manager
1038  *  (if you want to specify by a domainname)
1039  *
1040  *  or
1041  *
1042  * # echo '/usr/lib/ccs/editpolicy' > /sys/kernel/security/tomoyo/manager
1043  *  (if you want to specify by a program's location)
1044  *
1045  * and is deleted by
1046  *
1047  * # echo 'delete <kernel> /sbin/mingetty /bin/login /bin/bash' > \
1048  *                                        /sys/kernel/security/tomoyo/manager
1049  *
1050  *  or
1051  *
1052  * # echo 'delete /usr/lib/ccs/editpolicy' > \
1053  *                                        /sys/kernel/security/tomoyo/manager
1054  *
1055  * and all entries are retrieved by
1056  *
1057  * # cat /sys/kernel/security/tomoyo/manager
1058  */
1059 LIST_HEAD(tomoyo_policy_manager_list);
1060
1061 /**
1062  * tomoyo_update_manager_entry - Add a manager entry.
1063  *
1064  * @manager:   The path to manager or the domainnamme.
1065  * @is_delete: True if it is a delete request.
1066  *
1067  * Returns 0 on success, negative value otherwise.
1068  *
1069  * Caller holds tomoyo_read_lock().
1070  */
1071 static int tomoyo_update_manager_entry(const char *manager,
1072                                        const bool is_delete)
1073 {
1074         struct tomoyo_policy_manager_entry *entry = NULL;
1075         struct tomoyo_policy_manager_entry *ptr;
1076         const struct tomoyo_path_info *saved_manager;
1077         int error = is_delete ? -ENOENT : -ENOMEM;
1078         bool is_domain = false;
1079
1080         if (tomoyo_is_domain_def(manager)) {
1081                 if (!tomoyo_is_correct_domain(manager))
1082                         return -EINVAL;
1083                 is_domain = true;
1084         } else {
1085                 if (!tomoyo_is_correct_path(manager, 1, -1, -1))
1086                         return -EINVAL;
1087         }
1088         saved_manager = tomoyo_get_name(manager);
1089         if (!saved_manager)
1090                 return -ENOMEM;
1091         if (!is_delete)
1092                 entry = kmalloc(sizeof(*entry), GFP_NOFS);
1093         mutex_lock(&tomoyo_policy_lock);
1094         list_for_each_entry_rcu(ptr, &tomoyo_policy_manager_list, list) {
1095                 if (ptr->manager != saved_manager)
1096                         continue;
1097                 ptr->is_deleted = is_delete;
1098                 error = 0;
1099                 break;
1100         }
1101         if (!is_delete && error && tomoyo_memory_ok(entry)) {
1102                 entry->manager = saved_manager;
1103                 saved_manager = NULL;
1104                 entry->is_domain = is_domain;
1105                 list_add_tail_rcu(&entry->list, &tomoyo_policy_manager_list);
1106                 entry = NULL;
1107                 error = 0;
1108         }
1109         mutex_unlock(&tomoyo_policy_lock);
1110         tomoyo_put_name(saved_manager);
1111         kfree(entry);
1112         return error;
1113 }
1114
1115 /**
1116  * tomoyo_write_manager_policy - Write manager policy.
1117  *
1118  * @head: Pointer to "struct tomoyo_io_buffer".
1119  *
1120  * Returns 0 on success, negative value otherwise.
1121  *
1122  * Caller holds tomoyo_read_lock().
1123  */
1124 static int tomoyo_write_manager_policy(struct tomoyo_io_buffer *head)
1125 {
1126         char *data = head->write_buf;
1127         bool is_delete = tomoyo_str_starts(&data, TOMOYO_KEYWORD_DELETE);
1128
1129         if (!strcmp(data, "manage_by_non_root")) {
1130                 tomoyo_manage_by_non_root = !is_delete;
1131                 return 0;
1132         }
1133         return tomoyo_update_manager_entry(data, is_delete);
1134 }
1135
1136 /**
1137  * tomoyo_read_manager_policy - Read manager policy.
1138  *
1139  * @head: Pointer to "struct tomoyo_io_buffer".
1140  *
1141  * Returns 0.
1142  *
1143  * Caller holds tomoyo_read_lock().
1144  */
1145 static int tomoyo_read_manager_policy(struct tomoyo_io_buffer *head)
1146 {
1147         struct list_head *pos;
1148         bool done = true;
1149
1150         if (head->read_eof)
1151                 return 0;
1152         list_for_each_cookie(pos, head->read_var2,
1153                              &tomoyo_policy_manager_list) {
1154                 struct tomoyo_policy_manager_entry *ptr;
1155                 ptr = list_entry(pos, struct tomoyo_policy_manager_entry,
1156                                  list);
1157                 if (ptr->is_deleted)
1158                         continue;
1159                 done = tomoyo_io_printf(head, "%s\n", ptr->manager->name);
1160                 if (!done)
1161                         break;
1162         }
1163         head->read_eof = done;
1164         return 0;
1165 }
1166
1167 /**
1168  * tomoyo_is_policy_manager - Check whether the current process is a policy manager.
1169  *
1170  * Returns true if the current process is permitted to modify policy
1171  * via /sys/kernel/security/tomoyo/ interface.
1172  *
1173  * Caller holds tomoyo_read_lock().
1174  */
1175 static bool tomoyo_is_policy_manager(void)
1176 {
1177         struct tomoyo_policy_manager_entry *ptr;
1178         const char *exe;
1179         const struct task_struct *task = current;
1180         const struct tomoyo_path_info *domainname = tomoyo_domain()->domainname;
1181         bool found = false;
1182
1183         if (!tomoyo_policy_loaded)
1184                 return true;
1185         if (!tomoyo_manage_by_non_root && (task->cred->uid || task->cred->euid))
1186                 return false;
1187         list_for_each_entry_rcu(ptr, &tomoyo_policy_manager_list, list) {
1188                 if (!ptr->is_deleted && ptr->is_domain
1189                     && !tomoyo_pathcmp(domainname, ptr->manager)) {
1190                         found = true;
1191                         break;
1192                 }
1193         }
1194         if (found)
1195                 return true;
1196         exe = tomoyo_get_exe();
1197         if (!exe)
1198                 return false;
1199         list_for_each_entry_rcu(ptr, &tomoyo_policy_manager_list, list) {
1200                 if (!ptr->is_deleted && !ptr->is_domain
1201                     && !strcmp(exe, ptr->manager->name)) {
1202                         found = true;
1203                         break;
1204                 }
1205         }
1206         if (!found) { /* Reduce error messages. */
1207                 static pid_t last_pid;
1208                 const pid_t pid = current->pid;
1209                 if (last_pid != pid) {
1210                         printk(KERN_WARNING "%s ( %s ) is not permitted to "
1211                                "update policies.\n", domainname->name, exe);
1212                         last_pid = pid;
1213                 }
1214         }
1215         kfree(exe);
1216         return found;
1217 }
1218
1219 /**
1220  * tomoyo_is_select_one - Parse select command.
1221  *
1222  * @head: Pointer to "struct tomoyo_io_buffer".
1223  * @data: String to parse.
1224  *
1225  * Returns true on success, false otherwise.
1226  *
1227  * Caller holds tomoyo_read_lock().
1228  */
1229 static bool tomoyo_is_select_one(struct tomoyo_io_buffer *head,
1230                                  const char *data)
1231 {
1232         unsigned int pid;
1233         struct tomoyo_domain_info *domain = NULL;
1234
1235         if (sscanf(data, "pid=%u", &pid) == 1) {
1236                 struct task_struct *p;
1237                 rcu_read_lock();
1238                 read_lock(&tasklist_lock);
1239                 p = find_task_by_vpid(pid);
1240                 if (p)
1241                         domain = tomoyo_real_domain(p);
1242                 read_unlock(&tasklist_lock);
1243                 rcu_read_unlock();
1244         } else if (!strncmp(data, "domain=", 7)) {
1245                 if (tomoyo_is_domain_def(data + 7))
1246                         domain = tomoyo_find_domain(data + 7);
1247         } else
1248                 return false;
1249         head->write_var1 = domain;
1250         /* Accessing read_buf is safe because head->io_sem is held. */
1251         if (!head->read_buf)
1252                 return true; /* Do nothing if open(O_WRONLY). */
1253         head->read_avail = 0;
1254         tomoyo_io_printf(head, "# select %s\n", data);
1255         head->read_single_domain = true;
1256         head->read_eof = !domain;
1257         if (domain) {
1258                 struct tomoyo_domain_info *d;
1259                 head->read_var1 = NULL;
1260                 list_for_each_entry_rcu(d, &tomoyo_domain_list, list) {
1261                         if (d == domain)
1262                                 break;
1263                         head->read_var1 = &d->list;
1264                 }
1265                 head->read_var2 = NULL;
1266                 head->read_bit = 0;
1267                 head->read_step = 0;
1268                 if (domain->is_deleted)
1269                         tomoyo_io_printf(head, "# This is a deleted domain.\n");
1270         }
1271         return true;
1272 }
1273
1274 /**
1275  * tomoyo_delete_domain - Delete a domain.
1276  *
1277  * @domainname: The name of domain.
1278  *
1279  * Returns 0.
1280  *
1281  * Caller holds tomoyo_read_lock().
1282  */
1283 static int tomoyo_delete_domain(char *domainname)
1284 {
1285         struct tomoyo_domain_info *domain;
1286         struct tomoyo_path_info name;
1287
1288         name.name = domainname;
1289         tomoyo_fill_path_info(&name);
1290         mutex_lock(&tomoyo_policy_lock);
1291         /* Is there an active domain? */
1292         list_for_each_entry_rcu(domain, &tomoyo_domain_list, list) {
1293                 /* Never delete tomoyo_kernel_domain */
1294                 if (domain == &tomoyo_kernel_domain)
1295                         continue;
1296                 if (domain->is_deleted ||
1297                     tomoyo_pathcmp(domain->domainname, &name))
1298                         continue;
1299                 domain->is_deleted = true;
1300                 break;
1301         }
1302         mutex_unlock(&tomoyo_policy_lock);
1303         return 0;
1304 }
1305
1306 /**
1307  * tomoyo_write_domain_policy - Write domain policy.
1308  *
1309  * @head: Pointer to "struct tomoyo_io_buffer".
1310  *
1311  * Returns 0 on success, negative value otherwise.
1312  *
1313  * Caller holds tomoyo_read_lock().
1314  */
1315 static int tomoyo_write_domain_policy(struct tomoyo_io_buffer *head)
1316 {
1317         char *data = head->write_buf;
1318         struct tomoyo_domain_info *domain = head->write_var1;
1319         bool is_delete = false;
1320         bool is_select = false;
1321         unsigned int profile;
1322
1323         if (tomoyo_str_starts(&data, TOMOYO_KEYWORD_DELETE))
1324                 is_delete = true;
1325         else if (tomoyo_str_starts(&data, TOMOYO_KEYWORD_SELECT))
1326                 is_select = true;
1327         if (is_select && tomoyo_is_select_one(head, data))
1328                 return 0;
1329         /* Don't allow updating policies by non manager programs. */
1330         if (!tomoyo_is_policy_manager())
1331                 return -EPERM;
1332         if (tomoyo_is_domain_def(data)) {
1333                 domain = NULL;
1334                 if (is_delete)
1335                         tomoyo_delete_domain(data);
1336                 else if (is_select)
1337                         domain = tomoyo_find_domain(data);
1338                 else
1339                         domain = tomoyo_find_or_assign_new_domain(data, 0);
1340                 head->write_var1 = domain;
1341                 return 0;
1342         }
1343         if (!domain)
1344                 return -EINVAL;
1345
1346         if (sscanf(data, TOMOYO_KEYWORD_USE_PROFILE "%u", &profile) == 1
1347             && profile < TOMOYO_MAX_PROFILES) {
1348                 if (tomoyo_profile_ptr[profile] || !tomoyo_policy_loaded)
1349                         domain->profile = (u8) profile;
1350                 return 0;
1351         }
1352         if (!strcmp(data, TOMOYO_KEYWORD_IGNORE_GLOBAL_ALLOW_READ)) {
1353                 domain->ignore_global_allow_read = !is_delete;
1354                 return 0;
1355         }
1356         return tomoyo_write_file_policy(data, domain, is_delete);
1357 }
1358
1359 /**
1360  * tomoyo_print_path_acl - Print a single path ACL entry.
1361  *
1362  * @head: Pointer to "struct tomoyo_io_buffer".
1363  * @ptr:  Pointer to "struct tomoyo_path_acl".
1364  *
1365  * Returns true on success, false otherwise.
1366  */
1367 static bool tomoyo_print_path_acl(struct tomoyo_io_buffer *head,
1368                                   struct tomoyo_path_acl *ptr)
1369 {
1370         int pos;
1371         u8 bit;
1372         const char *filename;
1373         const u32 perm = ptr->perm | (((u32) ptr->perm_high) << 16);
1374
1375         filename = ptr->filename->name;
1376         for (bit = head->read_bit; bit < TOMOYO_MAX_PATH_OPERATION; bit++) {
1377                 const char *msg;
1378                 if (!(perm & (1 << bit)))
1379                         continue;
1380                 /* Print "read/write" instead of "read" and "write". */
1381                 if ((bit == TOMOYO_TYPE_READ || bit == TOMOYO_TYPE_WRITE)
1382                     && (perm & (1 << TOMOYO_TYPE_READ_WRITE)))
1383                         continue;
1384                 msg = tomoyo_path2keyword(bit);
1385                 pos = head->read_avail;
1386                 if (!tomoyo_io_printf(head, "allow_%s %s\n", msg, filename))
1387                         goto out;
1388         }
1389         head->read_bit = 0;
1390         return true;
1391  out:
1392         head->read_bit = bit;
1393         head->read_avail = pos;
1394         return false;
1395 }
1396
1397 /**
1398  * tomoyo_print_path2_acl - Print a double path ACL entry.
1399  *
1400  * @head: Pointer to "struct tomoyo_io_buffer".
1401  * @ptr:  Pointer to "struct tomoyo_path2_acl".
1402  *
1403  * Returns true on success, false otherwise.
1404  */
1405 static bool tomoyo_print_path2_acl(struct tomoyo_io_buffer *head,
1406                                    struct tomoyo_path2_acl *ptr)
1407 {
1408         int pos;
1409         const char *filename1;
1410         const char *filename2;
1411         const u8 perm = ptr->perm;
1412         u8 bit;
1413
1414         filename1 = ptr->filename1->name;
1415         filename2 = ptr->filename2->name;
1416         for (bit = head->read_bit; bit < TOMOYO_MAX_PATH2_OPERATION; bit++) {
1417                 const char *msg;
1418                 if (!(perm & (1 << bit)))
1419                         continue;
1420                 msg = tomoyo_path22keyword(bit);
1421                 pos = head->read_avail;
1422                 if (!tomoyo_io_printf(head, "allow_%s %s %s\n", msg,
1423                                       filename1, filename2))
1424                         goto out;
1425         }
1426         head->read_bit = 0;
1427         return true;
1428  out:
1429         head->read_bit = bit;
1430         head->read_avail = pos;
1431         return false;
1432 }
1433
1434 /**
1435  * tomoyo_print_entry - Print an ACL entry.
1436  *
1437  * @head: Pointer to "struct tomoyo_io_buffer".
1438  * @ptr:  Pointer to an ACL entry.
1439  *
1440  * Returns true on success, false otherwise.
1441  */
1442 static bool tomoyo_print_entry(struct tomoyo_io_buffer *head,
1443                                struct tomoyo_acl_info *ptr)
1444 {
1445         const u8 acl_type = ptr->type;
1446
1447         if (acl_type == TOMOYO_TYPE_PATH_ACL) {
1448                 struct tomoyo_path_acl *acl
1449                         = container_of(ptr, struct tomoyo_path_acl, head);
1450                 return tomoyo_print_path_acl(head, acl);
1451         }
1452         if (acl_type == TOMOYO_TYPE_PATH2_ACL) {
1453                 struct tomoyo_path2_acl *acl
1454                         = container_of(ptr, struct tomoyo_path2_acl, head);
1455                 return tomoyo_print_path2_acl(head, acl);
1456         }
1457         BUG(); /* This must not happen. */
1458         return false;
1459 }
1460
1461 /**
1462  * tomoyo_read_domain_policy - Read domain policy.
1463  *
1464  * @head: Pointer to "struct tomoyo_io_buffer".
1465  *
1466  * Returns 0.
1467  *
1468  * Caller holds tomoyo_read_lock().
1469  */
1470 static int tomoyo_read_domain_policy(struct tomoyo_io_buffer *head)
1471 {
1472         struct list_head *dpos;
1473         struct list_head *apos;
1474         bool done = true;
1475
1476         if (head->read_eof)
1477                 return 0;
1478         if (head->read_step == 0)
1479                 head->read_step = 1;
1480         list_for_each_cookie(dpos, head->read_var1, &tomoyo_domain_list) {
1481                 struct tomoyo_domain_info *domain;
1482                 const char *quota_exceeded = "";
1483                 const char *transition_failed = "";
1484                 const char *ignore_global_allow_read = "";
1485                 domain = list_entry(dpos, struct tomoyo_domain_info, list);
1486                 if (head->read_step != 1)
1487                         goto acl_loop;
1488                 if (domain->is_deleted && !head->read_single_domain)
1489                         continue;
1490                 /* Print domainname and flags. */
1491                 if (domain->quota_warned)
1492                         quota_exceeded = "quota_exceeded\n";
1493                 if (domain->transition_failed)
1494                         transition_failed = "transition_failed\n";
1495                 if (domain->ignore_global_allow_read)
1496                         ignore_global_allow_read
1497                                 = TOMOYO_KEYWORD_IGNORE_GLOBAL_ALLOW_READ "\n";
1498                 done = tomoyo_io_printf(head, "%s\n" TOMOYO_KEYWORD_USE_PROFILE
1499                                         "%u\n%s%s%s\n",
1500                                         domain->domainname->name,
1501                                         domain->profile, quota_exceeded,
1502                                         transition_failed,
1503                                         ignore_global_allow_read);
1504                 if (!done)
1505                         break;
1506                 head->read_step = 2;
1507 acl_loop:
1508                 if (head->read_step == 3)
1509                         goto tail_mark;
1510                 /* Print ACL entries in the domain. */
1511                 list_for_each_cookie(apos, head->read_var2,
1512                                      &domain->acl_info_list) {
1513                         struct tomoyo_acl_info *ptr
1514                                 = list_entry(apos, struct tomoyo_acl_info,
1515                                              list);
1516                         done = tomoyo_print_entry(head, ptr);
1517                         if (!done)
1518                                 break;
1519                 }
1520                 if (!done)
1521                         break;
1522                 head->read_step = 3;
1523 tail_mark:
1524                 done = tomoyo_io_printf(head, "\n");
1525                 if (!done)
1526                         break;
1527                 head->read_step = 1;
1528                 if (head->read_single_domain)
1529                         break;
1530         }
1531         head->read_eof = done;
1532         return 0;
1533 }
1534
1535 /**
1536  * tomoyo_write_domain_profile - Assign profile for specified domain.
1537  *
1538  * @head: Pointer to "struct tomoyo_io_buffer".
1539  *
1540  * Returns 0 on success, -EINVAL otherwise.
1541  *
1542  * This is equivalent to doing
1543  *
1544  *     ( echo "select " $domainname; echo "use_profile " $profile ) |
1545  *     /usr/lib/ccs/loadpolicy -d
1546  *
1547  * Caller holds tomoyo_read_lock().
1548  */
1549 static int tomoyo_write_domain_profile(struct tomoyo_io_buffer *head)
1550 {
1551         char *data = head->write_buf;
1552         char *cp = strchr(data, ' ');
1553         struct tomoyo_domain_info *domain;
1554         unsigned long profile;
1555
1556         if (!cp)
1557                 return -EINVAL;
1558         *cp = '\0';
1559         domain = tomoyo_find_domain(cp + 1);
1560         if (strict_strtoul(data, 10, &profile))
1561                 return -EINVAL;
1562         if (domain && profile < TOMOYO_MAX_PROFILES
1563             && (tomoyo_profile_ptr[profile] || !tomoyo_policy_loaded))
1564                 domain->profile = (u8) profile;
1565         return 0;
1566 }
1567
1568 /**
1569  * tomoyo_read_domain_profile - Read only domainname and profile.
1570  *
1571  * @head: Pointer to "struct tomoyo_io_buffer".
1572  *
1573  * Returns list of profile number and domainname pairs.
1574  *
1575  * This is equivalent to doing
1576  *
1577  *     grep -A 1 '^<kernel>' /sys/kernel/security/tomoyo/domain_policy |
1578  *     awk ' { if ( domainname == "" ) { if ( $1 == "<kernel>" )
1579  *     domainname = $0; } else if ( $1 == "use_profile" ) {
1580  *     print $2 " " domainname; domainname = ""; } } ; '
1581  *
1582  * Caller holds tomoyo_read_lock().
1583  */
1584 static int tomoyo_read_domain_profile(struct tomoyo_io_buffer *head)
1585 {
1586         struct list_head *pos;
1587         bool done = true;
1588
1589         if (head->read_eof)
1590                 return 0;
1591         list_for_each_cookie(pos, head->read_var1, &tomoyo_domain_list) {
1592                 struct tomoyo_domain_info *domain;
1593                 domain = list_entry(pos, struct tomoyo_domain_info, list);
1594                 if (domain->is_deleted)
1595                         continue;
1596                 done = tomoyo_io_printf(head, "%u %s\n", domain->profile,
1597                                         domain->domainname->name);
1598                 if (!done)
1599                         break;
1600         }
1601         head->read_eof = done;
1602         return 0;
1603 }
1604
1605 /**
1606  * tomoyo_write_pid: Specify PID to obtain domainname.
1607  *
1608  * @head: Pointer to "struct tomoyo_io_buffer".
1609  *
1610  * Returns 0.
1611  */
1612 static int tomoyo_write_pid(struct tomoyo_io_buffer *head)
1613 {
1614         unsigned long pid;
1615         /* No error check. */
1616         strict_strtoul(head->write_buf, 10, &pid);
1617         head->read_step = (int) pid;
1618         head->read_eof = false;
1619         return 0;
1620 }
1621
1622 /**
1623  * tomoyo_read_pid - Get domainname of the specified PID.
1624  *
1625  * @head: Pointer to "struct tomoyo_io_buffer".
1626  *
1627  * Returns the domainname which the specified PID is in on success,
1628  * empty string otherwise.
1629  * The PID is specified by tomoyo_write_pid() so that the user can obtain
1630  * using read()/write() interface rather than sysctl() interface.
1631  */
1632 static int tomoyo_read_pid(struct tomoyo_io_buffer *head)
1633 {
1634         if (head->read_avail == 0 && !head->read_eof) {
1635                 const int pid = head->read_step;
1636                 struct task_struct *p;
1637                 struct tomoyo_domain_info *domain = NULL;
1638                 rcu_read_lock();
1639                 read_lock(&tasklist_lock);
1640                 p = find_task_by_vpid(pid);
1641                 if (p)
1642                         domain = tomoyo_real_domain(p);
1643                 read_unlock(&tasklist_lock);
1644                 rcu_read_unlock();
1645                 if (domain)
1646                         tomoyo_io_printf(head, "%d %u %s", pid, domain->profile,
1647                                          domain->domainname->name);
1648                 head->read_eof = true;
1649         }
1650         return 0;
1651 }
1652
1653 /**
1654  * tomoyo_write_exception_policy - Write exception policy.
1655  *
1656  * @head: Pointer to "struct tomoyo_io_buffer".
1657  *
1658  * Returns 0 on success, negative value otherwise.
1659  *
1660  * Caller holds tomoyo_read_lock().
1661  */
1662 static int tomoyo_write_exception_policy(struct tomoyo_io_buffer *head)
1663 {
1664         char *data = head->write_buf;
1665         bool is_delete = tomoyo_str_starts(&data, TOMOYO_KEYWORD_DELETE);
1666
1667         if (tomoyo_str_starts(&data, TOMOYO_KEYWORD_KEEP_DOMAIN))
1668                 return tomoyo_write_domain_keeper_policy(data, false,
1669                                                          is_delete);
1670         if (tomoyo_str_starts(&data, TOMOYO_KEYWORD_NO_KEEP_DOMAIN))
1671                 return tomoyo_write_domain_keeper_policy(data, true, is_delete);
1672         if (tomoyo_str_starts(&data, TOMOYO_KEYWORD_INITIALIZE_DOMAIN))
1673                 return tomoyo_write_domain_initializer_policy(data, false,
1674                                                               is_delete);
1675         if (tomoyo_str_starts(&data, TOMOYO_KEYWORD_NO_INITIALIZE_DOMAIN))
1676                 return tomoyo_write_domain_initializer_policy(data, true,
1677                                                               is_delete);
1678         if (tomoyo_str_starts(&data, TOMOYO_KEYWORD_ALIAS))
1679                 return tomoyo_write_alias_policy(data, is_delete);
1680         if (tomoyo_str_starts(&data, TOMOYO_KEYWORD_ALLOW_READ))
1681                 return tomoyo_write_globally_readable_policy(data, is_delete);
1682         if (tomoyo_str_starts(&data, TOMOYO_KEYWORD_FILE_PATTERN))
1683                 return tomoyo_write_pattern_policy(data, is_delete);
1684         if (tomoyo_str_starts(&data, TOMOYO_KEYWORD_DENY_REWRITE))
1685                 return tomoyo_write_no_rewrite_policy(data, is_delete);
1686         return -EINVAL;
1687 }
1688
1689 /**
1690  * tomoyo_read_exception_policy - Read exception policy.
1691  *
1692  * @head: Pointer to "struct tomoyo_io_buffer".
1693  *
1694  * Returns 0 on success, -EINVAL otherwise.
1695  *
1696  * Caller holds tomoyo_read_lock().
1697  */
1698 static int tomoyo_read_exception_policy(struct tomoyo_io_buffer *head)
1699 {
1700         if (!head->read_eof) {
1701                 switch (head->read_step) {
1702                 case 0:
1703                         head->read_var2 = NULL;
1704                         head->read_step = 1;
1705                 case 1:
1706                         if (!tomoyo_read_domain_keeper_policy(head))
1707                                 break;
1708                         head->read_var2 = NULL;
1709                         head->read_step = 2;
1710                 case 2:
1711                         if (!tomoyo_read_globally_readable_policy(head))
1712                                 break;
1713                         head->read_var2 = NULL;
1714                         head->read_step = 3;
1715                 case 3:
1716                         head->read_var2 = NULL;
1717                         head->read_step = 4;
1718                 case 4:
1719                         if (!tomoyo_read_domain_initializer_policy(head))
1720                                 break;
1721                         head->read_var2 = NULL;
1722                         head->read_step = 5;
1723                 case 5:
1724                         if (!tomoyo_read_alias_policy(head))
1725                                 break;
1726                         head->read_var2 = NULL;
1727                         head->read_step = 6;
1728                 case 6:
1729                         head->read_var2 = NULL;
1730                         head->read_step = 7;
1731                 case 7:
1732                         if (!tomoyo_read_file_pattern(head))
1733                                 break;
1734                         head->read_var2 = NULL;
1735                         head->read_step = 8;
1736                 case 8:
1737                         if (!tomoyo_read_no_rewrite_policy(head))
1738                                 break;
1739                         head->read_var2 = NULL;
1740                         head->read_step = 9;
1741                 case 9:
1742                         head->read_eof = true;
1743                         break;
1744                 default:
1745                         return -EINVAL;
1746                 }
1747         }
1748         return 0;
1749 }
1750
1751 /* path to policy loader */
1752 static const char *tomoyo_loader = "/sbin/tomoyo-init";
1753
1754 /**
1755  * tomoyo_policy_loader_exists - Check whether /sbin/tomoyo-init exists.
1756  *
1757  * Returns true if /sbin/tomoyo-init exists, false otherwise.
1758  */
1759 static bool tomoyo_policy_loader_exists(void)
1760 {
1761         /*
1762          * Don't activate MAC if the policy loader doesn't exist.
1763          * If the initrd includes /sbin/init but real-root-dev has not
1764          * mounted on / yet, activating MAC will block the system since
1765          * policies are not loaded yet.
1766          * Thus, let do_execve() call this function everytime.
1767          */
1768         struct path path;
1769
1770         if (kern_path(tomoyo_loader, LOOKUP_FOLLOW, &path)) {
1771                 printk(KERN_INFO "Not activating Mandatory Access Control now "
1772                        "since %s doesn't exist.\n", tomoyo_loader);
1773                 return false;
1774         }
1775         path_put(&path);
1776         return true;
1777 }
1778
1779 /**
1780  * tomoyo_load_policy - Run external policy loader to load policy.
1781  *
1782  * @filename: The program about to start.
1783  *
1784  * This function checks whether @filename is /sbin/init , and if so
1785  * invoke /sbin/tomoyo-init and wait for the termination of /sbin/tomoyo-init
1786  * and then continues invocation of /sbin/init.
1787  * /sbin/tomoyo-init reads policy files in /etc/tomoyo/ directory and
1788  * writes to /sys/kernel/security/tomoyo/ interfaces.
1789  *
1790  * Returns nothing.
1791  */
1792 void tomoyo_load_policy(const char *filename)
1793 {
1794         char *argv[2];
1795         char *envp[3];
1796
1797         if (tomoyo_policy_loaded)
1798                 return;
1799         /*
1800          * Check filename is /sbin/init or /sbin/tomoyo-start.
1801          * /sbin/tomoyo-start is a dummy filename in case where /sbin/init can't
1802          * be passed.
1803          * You can create /sbin/tomoyo-start by
1804          * "ln -s /bin/true /sbin/tomoyo-start".
1805          */
1806         if (strcmp(filename, "/sbin/init") &&
1807             strcmp(filename, "/sbin/tomoyo-start"))
1808                 return;
1809         if (!tomoyo_policy_loader_exists())
1810                 return;
1811
1812         printk(KERN_INFO "Calling %s to load policy. Please wait.\n",
1813                tomoyo_loader);
1814         argv[0] = (char *) tomoyo_loader;
1815         argv[1] = NULL;
1816         envp[0] = "HOME=/";
1817         envp[1] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";
1818         envp[2] = NULL;
1819         call_usermodehelper(argv[0], argv, envp, 1);
1820
1821         printk(KERN_INFO "TOMOYO: 2.2.0   2009/04/01\n");
1822         printk(KERN_INFO "Mandatory Access Control activated.\n");
1823         tomoyo_policy_loaded = true;
1824         { /* Check all profiles currently assigned to domains are defined. */
1825                 struct tomoyo_domain_info *domain;
1826                 list_for_each_entry_rcu(domain, &tomoyo_domain_list, list) {
1827                         const u8 profile = domain->profile;
1828                         if (tomoyo_profile_ptr[profile])
1829                                 continue;
1830                         panic("Profile %u (used by '%s') not defined.\n",
1831                               profile, domain->domainname->name);
1832                 }
1833         }
1834 }
1835
1836 /**
1837  * tomoyo_read_version: Get version.
1838  *
1839  * @head: Pointer to "struct tomoyo_io_buffer".
1840  *
1841  * Returns version information.
1842  */
1843 static int tomoyo_read_version(struct tomoyo_io_buffer *head)
1844 {
1845         if (!head->read_eof) {
1846                 tomoyo_io_printf(head, "2.2.0");
1847                 head->read_eof = true;
1848         }
1849         return 0;
1850 }
1851
1852 /**
1853  * tomoyo_read_self_domain - Get the current process's domainname.
1854  *
1855  * @head: Pointer to "struct tomoyo_io_buffer".
1856  *
1857  * Returns the current process's domainname.
1858  */
1859 static int tomoyo_read_self_domain(struct tomoyo_io_buffer *head)
1860 {
1861         if (!head->read_eof) {
1862                 /*
1863                  * tomoyo_domain()->domainname != NULL
1864                  * because every process belongs to a domain and
1865                  * the domain's name cannot be NULL.
1866                  */
1867                 tomoyo_io_printf(head, "%s", tomoyo_domain()->domainname->name);
1868                 head->read_eof = true;
1869         }
1870         return 0;
1871 }
1872
1873 /**
1874  * tomoyo_open_control - open() for /sys/kernel/security/tomoyo/ interface.
1875  *
1876  * @type: Type of interface.
1877  * @file: Pointer to "struct file".
1878  *
1879  * Associates policy handler and returns 0 on success, -ENOMEM otherwise.
1880  *
1881  * Caller acquires tomoyo_read_lock().
1882  */
1883 static int tomoyo_open_control(const u8 type, struct file *file)
1884 {
1885         struct tomoyo_io_buffer *head = kzalloc(sizeof(*head), GFP_NOFS);
1886
1887         if (!head)
1888                 return -ENOMEM;
1889         mutex_init(&head->io_sem);
1890         switch (type) {
1891         case TOMOYO_DOMAINPOLICY:
1892                 /* /sys/kernel/security/tomoyo/domain_policy */
1893                 head->write = tomoyo_write_domain_policy;
1894                 head->read = tomoyo_read_domain_policy;
1895                 break;
1896         case TOMOYO_EXCEPTIONPOLICY:
1897                 /* /sys/kernel/security/tomoyo/exception_policy */
1898                 head->write = tomoyo_write_exception_policy;
1899                 head->read = tomoyo_read_exception_policy;
1900                 break;
1901         case TOMOYO_SELFDOMAIN:
1902                 /* /sys/kernel/security/tomoyo/self_domain */
1903                 head->read = tomoyo_read_self_domain;
1904                 break;
1905         case TOMOYO_DOMAIN_STATUS:
1906                 /* /sys/kernel/security/tomoyo/.domain_status */
1907                 head->write = tomoyo_write_domain_profile;
1908                 head->read = tomoyo_read_domain_profile;
1909                 break;
1910         case TOMOYO_PROCESS_STATUS:
1911                 /* /sys/kernel/security/tomoyo/.process_status */
1912                 head->write = tomoyo_write_pid;
1913                 head->read = tomoyo_read_pid;
1914                 break;
1915         case TOMOYO_VERSION:
1916                 /* /sys/kernel/security/tomoyo/version */
1917                 head->read = tomoyo_read_version;
1918                 head->readbuf_size = 128;
1919                 break;
1920         case TOMOYO_MEMINFO:
1921                 /* /sys/kernel/security/tomoyo/meminfo */
1922                 head->write = tomoyo_write_memory_quota;
1923                 head->read = tomoyo_read_memory_counter;
1924                 head->readbuf_size = 512;
1925                 break;
1926         case TOMOYO_PROFILE:
1927                 /* /sys/kernel/security/tomoyo/profile */
1928                 head->write = tomoyo_write_profile;
1929                 head->read = tomoyo_read_profile;
1930                 break;
1931         case TOMOYO_MANAGER:
1932                 /* /sys/kernel/security/tomoyo/manager */
1933                 head->write = tomoyo_write_manager_policy;
1934                 head->read = tomoyo_read_manager_policy;
1935                 break;
1936         }
1937         if (!(file->f_mode & FMODE_READ)) {
1938                 /*
1939                  * No need to allocate read_buf since it is not opened
1940                  * for reading.
1941                  */
1942                 head->read = NULL;
1943         } else {
1944                 if (!head->readbuf_size)
1945                         head->readbuf_size = 4096 * 2;
1946                 head->read_buf = kzalloc(head->readbuf_size, GFP_NOFS);
1947                 if (!head->read_buf) {
1948                         kfree(head);
1949                         return -ENOMEM;
1950                 }
1951         }
1952         if (!(file->f_mode & FMODE_WRITE)) {
1953                 /*
1954                  * No need to allocate write_buf since it is not opened
1955                  * for writing.
1956                  */
1957                 head->write = NULL;
1958         } else if (head->write) {
1959                 head->writebuf_size = 4096 * 2;
1960                 head->write_buf = kzalloc(head->writebuf_size, GFP_NOFS);
1961                 if (!head->write_buf) {
1962                         kfree(head->read_buf);
1963                         kfree(head);
1964                         return -ENOMEM;
1965                 }
1966         }
1967         head->reader_idx = tomoyo_read_lock();
1968         file->private_data = head;
1969         /*
1970          * Call the handler now if the file is
1971          * /sys/kernel/security/tomoyo/self_domain
1972          * so that the user can use
1973          * cat < /sys/kernel/security/tomoyo/self_domain"
1974          * to know the current process's domainname.
1975          */
1976         if (type == TOMOYO_SELFDOMAIN)
1977                 tomoyo_read_control(file, NULL, 0);
1978         return 0;
1979 }
1980
1981 /**
1982  * tomoyo_read_control - read() for /sys/kernel/security/tomoyo/ interface.
1983  *
1984  * @file:       Pointer to "struct file".
1985  * @buffer:     Poiner to buffer to write to.
1986  * @buffer_len: Size of @buffer.
1987  *
1988  * Returns bytes read on success, negative value otherwise.
1989  *
1990  * Caller holds tomoyo_read_lock().
1991  */
1992 static int tomoyo_read_control(struct file *file, char __user *buffer,
1993                                const int buffer_len)
1994 {
1995         int len = 0;
1996         struct tomoyo_io_buffer *head = file->private_data;
1997         char *cp;
1998
1999         if (!head->read)
2000                 return -ENOSYS;
2001         if (mutex_lock_interruptible(&head->io_sem))
2002                 return -EINTR;
2003         /* Call the policy handler. */
2004         len = head->read(head);
2005         if (len < 0)
2006                 goto out;
2007         /* Write to buffer. */
2008         len = head->read_avail;
2009         if (len > buffer_len)
2010                 len = buffer_len;
2011         if (!len)
2012                 goto out;
2013         /* head->read_buf changes by some functions. */
2014         cp = head->read_buf;
2015         if (copy_to_user(buffer, cp, len)) {
2016                 len = -EFAULT;
2017                 goto out;
2018         }
2019         head->read_avail -= len;
2020         memmove(cp, cp + len, head->read_avail);
2021  out:
2022         mutex_unlock(&head->io_sem);
2023         return len;
2024 }
2025
2026 /**
2027  * tomoyo_write_control - write() for /sys/kernel/security/tomoyo/ interface.
2028  *
2029  * @file:       Pointer to "struct file".
2030  * @buffer:     Pointer to buffer to read from.
2031  * @buffer_len: Size of @buffer.
2032  *
2033  * Returns @buffer_len on success, negative value otherwise.
2034  *
2035  * Caller holds tomoyo_read_lock().
2036  */
2037 static int tomoyo_write_control(struct file *file, const char __user *buffer,
2038                                 const int buffer_len)
2039 {
2040         struct tomoyo_io_buffer *head = file->private_data;
2041         int error = buffer_len;
2042         int avail_len = buffer_len;
2043         char *cp0 = head->write_buf;
2044
2045         if (!head->write)
2046                 return -ENOSYS;
2047         if (!access_ok(VERIFY_READ, buffer, buffer_len))
2048                 return -EFAULT;
2049         /* Don't allow updating policies by non manager programs. */
2050         if (head->write != tomoyo_write_pid &&
2051             head->write != tomoyo_write_domain_policy &&
2052             !tomoyo_is_policy_manager())
2053                 return -EPERM;
2054         if (mutex_lock_interruptible(&head->io_sem))
2055                 return -EINTR;
2056         /* Read a line and dispatch it to the policy handler. */
2057         while (avail_len > 0) {
2058                 char c;
2059                 if (head->write_avail >= head->writebuf_size - 1) {
2060                         error = -ENOMEM;
2061                         break;
2062                 } else if (get_user(c, buffer)) {
2063                         error = -EFAULT;
2064                         break;
2065                 }
2066                 buffer++;
2067                 avail_len--;
2068                 cp0[head->write_avail++] = c;
2069                 if (c != '\n')
2070                         continue;
2071                 cp0[head->write_avail - 1] = '\0';
2072                 head->write_avail = 0;
2073                 tomoyo_normalize_line(cp0);
2074                 head->write(head);
2075         }
2076         mutex_unlock(&head->io_sem);
2077         return error;
2078 }
2079
2080 /**
2081  * tomoyo_close_control - close() for /sys/kernel/security/tomoyo/ interface.
2082  *
2083  * @file: Pointer to "struct file".
2084  *
2085  * Releases memory and returns 0.
2086  *
2087  * Caller looses tomoyo_read_lock().
2088  */
2089 static int tomoyo_close_control(struct file *file)
2090 {
2091         struct tomoyo_io_buffer *head = file->private_data;
2092         const bool is_write = !!head->write_buf;
2093
2094         tomoyo_read_unlock(head->reader_idx);
2095         /* Release memory used for policy I/O. */
2096         kfree(head->read_buf);
2097         head->read_buf = NULL;
2098         kfree(head->write_buf);
2099         head->write_buf = NULL;
2100         kfree(head);
2101         head = NULL;
2102         file->private_data = NULL;
2103         if (is_write)
2104                 tomoyo_run_gc();
2105         return 0;
2106 }
2107
2108 /**
2109  * tomoyo_open - open() for /sys/kernel/security/tomoyo/ interface.
2110  *
2111  * @inode: Pointer to "struct inode".
2112  * @file:  Pointer to "struct file".
2113  *
2114  * Returns 0 on success, negative value otherwise.
2115  */
2116 static int tomoyo_open(struct inode *inode, struct file *file)
2117 {
2118         const int key = ((u8 *) file->f_path.dentry->d_inode->i_private)
2119                 - ((u8 *) NULL);
2120         return tomoyo_open_control(key, file);
2121 }
2122
2123 /**
2124  * tomoyo_release - close() for /sys/kernel/security/tomoyo/ interface.
2125  *
2126  * @inode: Pointer to "struct inode".
2127  * @file:  Pointer to "struct file".
2128  *
2129  * Returns 0 on success, negative value otherwise.
2130  */
2131 static int tomoyo_release(struct inode *inode, struct file *file)
2132 {
2133         return tomoyo_close_control(file);
2134 }
2135
2136 /**
2137  * tomoyo_read - read() for /sys/kernel/security/tomoyo/ interface.
2138  *
2139  * @file:  Pointer to "struct file".
2140  * @buf:   Pointer to buffer.
2141  * @count: Size of @buf.
2142  * @ppos:  Unused.
2143  *
2144  * Returns bytes read on success, negative value otherwise.
2145  */
2146 static ssize_t tomoyo_read(struct file *file, char __user *buf, size_t count,
2147                            loff_t *ppos)
2148 {
2149         return tomoyo_read_control(file, buf, count);
2150 }
2151
2152 /**
2153  * tomoyo_write - write() for /sys/kernel/security/tomoyo/ interface.
2154  *
2155  * @file:  Pointer to "struct file".
2156  * @buf:   Pointer to buffer.
2157  * @count: Size of @buf.
2158  * @ppos:  Unused.
2159  *
2160  * Returns @count on success, negative value otherwise.
2161  */
2162 static ssize_t tomoyo_write(struct file *file, const char __user *buf,
2163                             size_t count, loff_t *ppos)
2164 {
2165         return tomoyo_write_control(file, buf, count);
2166 }
2167
2168 /*
2169  * tomoyo_operations is a "struct file_operations" which is used for handling
2170  * /sys/kernel/security/tomoyo/ interface.
2171  *
2172  * Some files under /sys/kernel/security/tomoyo/ directory accept open(O_RDWR).
2173  * See tomoyo_io_buffer for internals.
2174  */
2175 static const struct file_operations tomoyo_operations = {
2176         .open    = tomoyo_open,
2177         .release = tomoyo_release,
2178         .read    = tomoyo_read,
2179         .write   = tomoyo_write,
2180 };
2181
2182 /**
2183  * tomoyo_create_entry - Create interface files under /sys/kernel/security/tomoyo/ directory.
2184  *
2185  * @name:   The name of the interface file.
2186  * @mode:   The permission of the interface file.
2187  * @parent: The parent directory.
2188  * @key:    Type of interface.
2189  *
2190  * Returns nothing.
2191  */
2192 static void __init tomoyo_create_entry(const char *name, const mode_t mode,
2193                                        struct dentry *parent, const u8 key)
2194 {
2195         securityfs_create_file(name, mode, parent, ((u8 *) NULL) + key,
2196                                &tomoyo_operations);
2197 }
2198
2199 /**
2200  * tomoyo_initerface_init - Initialize /sys/kernel/security/tomoyo/ interface.
2201  *
2202  * Returns 0.
2203  */
2204 static int __init tomoyo_initerface_init(void)
2205 {
2206         struct dentry *tomoyo_dir;
2207
2208         /* Don't create securityfs entries unless registered. */
2209         if (current_cred()->security != &tomoyo_kernel_domain)
2210                 return 0;
2211
2212         tomoyo_dir = securityfs_create_dir("tomoyo", NULL);
2213         tomoyo_create_entry("domain_policy",    0600, tomoyo_dir,
2214                             TOMOYO_DOMAINPOLICY);
2215         tomoyo_create_entry("exception_policy", 0600, tomoyo_dir,
2216                             TOMOYO_EXCEPTIONPOLICY);
2217         tomoyo_create_entry("self_domain",      0400, tomoyo_dir,
2218                             TOMOYO_SELFDOMAIN);
2219         tomoyo_create_entry(".domain_status",   0600, tomoyo_dir,
2220                             TOMOYO_DOMAIN_STATUS);
2221         tomoyo_create_entry(".process_status",  0600, tomoyo_dir,
2222                             TOMOYO_PROCESS_STATUS);
2223         tomoyo_create_entry("meminfo",          0600, tomoyo_dir,
2224                             TOMOYO_MEMINFO);
2225         tomoyo_create_entry("profile",          0600, tomoyo_dir,
2226                             TOMOYO_PROFILE);
2227         tomoyo_create_entry("manager",          0600, tomoyo_dir,
2228                             TOMOYO_MANAGER);
2229         tomoyo_create_entry("version",          0400, tomoyo_dir,
2230                             TOMOYO_VERSION);
2231         return 0;
2232 }
2233
2234 fs_initcall(tomoyo_initerface_init);