security/tomoyo/common.h

   1 /*
   2  * security/tomoyo/common.h
   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 #ifndef _SECURITY_TOMOYO_COMMON_H
  13 #define _SECURITY_TOMOYO_COMMON_H
  14
  15 #include <linux/ctype.h>
  16 #include <linux/string.h>
  17 #include <linux/mm.h>
  18 #include <linux/file.h>
  19 #include <linux/kmod.h>
  20 #include <linux/fs.h>
  21 #include <linux/sched.h>
  22 #include <linux/namei.h>
  23 #include <linux/mount.h>
  24 #include <linux/list.h>
  25
  26 struct dentry;
  27 struct vfsmount;
  28
  29 /*
  30  * tomoyo_page_buffer is a structure which is used for holding a pathname
  31  * obtained from "struct dentry" and "struct vfsmount" pair.
  32  * As of now, it is 4096 bytes. If users complain that 4096 bytes is too small
  33  * (because TOMOYO escapes non ASCII printable characters using \ooo format),
  34  * we will make the buffer larger.
  35  */
  36 struct tomoyo_page_buffer {
  37         char buffer[4096];
  38 };
  39
  40 /*
  41  * tomoyo_path_info is a structure which is used for holding a string data
  42  * used by TOMOYO.
  43  * This structure has several fields for supporting pattern matching.
  44  *
  45  * (1) "name" is the '\0' terminated string data.
  46  * (2) "hash" is full_name_hash(name, strlen(name)).
  47  *     This allows tomoyo_pathcmp() to compare by hash before actually compare
  48  *     using strcmp().
  49  * (3) "const_len" is the length of the initial segment of "name" which
  50  *     consists entirely of non wildcard characters. In other words, the length
  51  *     which we can compare two strings using strncmp().
  52  * (4) "is_dir" is a bool which is true if "name" ends with "/",
  53  *     false otherwise.
  54  *     TOMOYO distinguishes directory and non-directory. A directory ends with
  55  *     "/" and non-directory does not end with "/".
  56  * (5) "is_patterned" is a bool which is true if "name" contains wildcard
  57  *     characters, false otherwise. This allows TOMOYO to use "hash" and
  58  *     strcmp() for string comparison if "is_patterned" is false.
  59  * (6) "depth" is calculated using the number of "/" characters in "name".
  60  *     This allows TOMOYO to avoid comparing two pathnames which never match
  61  *     (e.g. whether "/var/www/html/index.html" matches "/tmp/sh-thd-\$").
  62  */
  63 struct tomoyo_path_info {
  64         const char *name;
  65         u32 hash;          /* = full_name_hash(name, strlen(name)) */
  66         u16 const_len;     /* = tomoyo_const_part_length(name)     */
  67         bool is_dir;       /* = tomoyo_strendswith(name, "/")      */
  68         bool is_patterned; /* = tomoyo_path_contains_pattern(name) */
  69         u16 depth;         /* = tomoyo_path_depth(name)            */
  70 };
  71
  72 /*
  73  * This is the max length of a token.
  74  *
  75  * A token consists of only ASCII printable characters.
  76  * Non printable characters in a token is represented in \ooo style
  77  * octal string. Thus, \ itself is represented as \\.
  78  */
  79 #define TOMOYO_MAX_PATHNAME_LEN 4000
  80
  81 /*
  82  * tomoyo_path_info_with_data is a structure which is used for holding a
  83  * pathname obtained from "struct dentry" and "struct vfsmount" pair.
  84  *
  85  * "struct tomoyo_path_info_with_data" consists of "struct tomoyo_path_info"
  86  * and buffer for the pathname, while "struct tomoyo_page_buffer" consists of
  87  * buffer for the pathname only.
  88  *
  89  * "struct tomoyo_path_info_with_data" is intended to allow TOMOYO to release
  90  * both "struct tomoyo_path_info" and buffer for the pathname by single kfree()
  91  * so that we don't need to return two pointers to the caller. If the caller
  92  * puts "struct tomoyo_path_info" on stack memory, we will be able to remove
  93  * "struct tomoyo_path_info_with_data".
  94  */
  95 struct tomoyo_path_info_with_data {
  96         /* Keep "head" first, for this pointer is passed to tomoyo_free(). */
  97         struct tomoyo_path_info head;
  98         char barrier1[16]; /* Safeguard for overrun. */
  99         char body[TOMOYO_MAX_PATHNAME_LEN];
 100         char barrier2[16]; /* Safeguard for overrun. */
 101 };
 102
 103 /*
 104  * tomoyo_acl_info is a structure which is used for holding
 105  *
 106  *  (1) "list" which is linked to the ->acl_info_list of
 107  *      "struct tomoyo_domain_info"
 108  *  (2) "type" which tells
 109  *      (a) type & 0x7F : type of the entry (either
 110  *          "struct tomoyo_single_path_acl_record" or
 111  *          "struct tomoyo_double_path_acl_record")
 112  *      (b) type & 0x80 : whether the entry is marked as "deleted".
 113  *
 114  * Packing "struct tomoyo_acl_info" allows
 115  * "struct tomoyo_single_path_acl_record" to embed "u16" and
 116  * "struct tomoyo_double_path_acl_record" to embed "u8"
 117  * without enlarging their structure size.
 118  */
 119 struct tomoyo_acl_info {
 120         struct list_head list;
 121         /*
 122          * Type of this ACL entry.
 123          *
 124          * MSB is is_deleted flag.
 125          */
 126         u8 type;
 127 } __packed;
 128
 129 /* This ACL entry is deleted.           */
 130 #define TOMOYO_ACL_DELETED        0x80
 131
 132 /*
 133  * tomoyo_domain_info is a structure which is used for holding permissions
 134  * (e.g. "allow_read /lib/libc-2.5.so") given to each domain.
 135  * It has following fields.
 136  *
 137  *  (1) "list" which is linked to tomoyo_domain_list .
 138  *  (2) "acl_info_list" which is linked to "struct tomoyo_acl_info".
 139  *  (3) "domainname" which holds the name of the domain.
 140  *  (4) "profile" which remembers profile number assigned to this domain.
 141  *  (5) "is_deleted" is a bool which is true if this domain is marked as
 142  *      "deleted", false otherwise.
 143  *  (6) "quota_warned" is a bool which is used for suppressing warning message
 144  *      when learning mode learned too much entries.
 145  *  (7) "flags" which remembers this domain's attributes.
 146  *
 147  * A domain's lifecycle is an analogy of files on / directory.
 148  * Multiple domains with the same domainname cannot be created (as with
 149  * creating files with the same filename fails with -EEXIST).
 150  * If a process reached a domain, that process can reside in that domain after
 151  * that domain is marked as "deleted" (as with a process can access an already
 152  * open()ed file after that file was unlink()ed).
 153  */
 154 struct tomoyo_domain_info {
 155         struct list_head list;
 156         struct list_head acl_info_list;
 157         /* Name of this domain. Never NULL.          */
 158         const struct tomoyo_path_info *domainname;
 159         u8 profile;        /* Profile number to use. */
 160         bool is_deleted;   /* Delete flag.           */
 161         bool quota_warned; /* Quota warnning flag.   */
 162         /* DOMAIN_FLAGS_*. Use tomoyo_set_domain_flag() to modify. */
 163         u8 flags;
 164 };
 165
 166 /* Profile number is an integer between 0 and 255. */
 167 #define TOMOYO_MAX_PROFILES 256
 168
 169 /* Ignore "allow_read" directive in exception policy. */
 170 #define TOMOYO_DOMAIN_FLAGS_IGNORE_GLOBAL_ALLOW_READ 1
 171 /*
 172  * This domain was unable to create a new domain at tomoyo_find_next_domain()
 173  * because the name of the domain to be created was too long or
 174  * it could not allocate memory.
 175  * More than one process continued execve() without domain transition.
 176  */
 177 #define TOMOYO_DOMAIN_FLAGS_TRANSITION_FAILED        2
 178
 179 /*
 180  * tomoyo_single_path_acl_record is a structure which is used for holding an
 181  * entry with one pathname operation (e.g. open(), mkdir()).
 182  * It has following fields.
 183  *
 184  *  (1) "head" which is a "struct tomoyo_acl_info".
 185  *  (2) "perm" which is a bitmask of permitted operations.
 186  *  (3) "filename" is the pathname.
 187  *
 188  * Directives held by this structure are "allow_read/write", "allow_execute",
 189  * "allow_read", "allow_write", "allow_create", "allow_unlink", "allow_mkdir",
 190  * "allow_rmdir", "allow_mkfifo", "allow_mksock", "allow_mkblock",
 191  * "allow_mkchar", "allow_truncate", "allow_symlink" and "allow_rewrite".
 192  */
 193 struct tomoyo_single_path_acl_record {
 194         struct tomoyo_acl_info head; /* type = TOMOYO_TYPE_SINGLE_PATH_ACL */
 195         u16 perm;
 196         /* Pointer to single pathname. */
 197         const struct tomoyo_path_info *filename;
 198 };
 199
 200 /*
 201  * tomoyo_double_path_acl_record is a structure which is used for holding an
 202  * entry with two pathnames operation (i.e. link() and rename()).
 203  * It has following fields.
 204  *
 205  *  (1) "head" which is a "struct tomoyo_acl_info".
 206  *  (2) "perm" which is a bitmask of permitted operations.
 207  *  (3) "filename1" is the source/old pathname.
 208  *  (4) "filename2" is the destination/new pathname.
 209  *
 210  * Directives held by this structure are "allow_rename" and "allow_link".
 211  */
 212 struct tomoyo_double_path_acl_record {
 213         struct tomoyo_acl_info head; /* type = TOMOYO_TYPE_DOUBLE_PATH_ACL */
 214         u8 perm;
 215         /* Pointer to single pathname. */
 216         const struct tomoyo_path_info *filename1;
 217         /* Pointer to single pathname. */
 218         const struct tomoyo_path_info *filename2;
 219 };
 220
 221 /* Keywords for ACLs. */
 222 #define TOMOYO_KEYWORD_ALIAS                     "alias "
 223 #define TOMOYO_KEYWORD_ALLOW_READ                "allow_read "
 224 #define TOMOYO_KEYWORD_DELETE                    "delete "
 225 #define TOMOYO_KEYWORD_DENY_REWRITE              "deny_rewrite "
 226 #define TOMOYO_KEYWORD_FILE_PATTERN              "file_pattern "
 227 #define TOMOYO_KEYWORD_INITIALIZE_DOMAIN         "initialize_domain "
 228 #define TOMOYO_KEYWORD_KEEP_DOMAIN               "keep_domain "
 229 #define TOMOYO_KEYWORD_NO_INITIALIZE_DOMAIN      "no_initialize_domain "
 230 #define TOMOYO_KEYWORD_NO_KEEP_DOMAIN            "no_keep_domain "
 231 #define TOMOYO_KEYWORD_SELECT                    "select "
 232 #define TOMOYO_KEYWORD_USE_PROFILE               "use_profile "
 233 #define TOMOYO_KEYWORD_IGNORE_GLOBAL_ALLOW_READ  "ignore_global_allow_read"
 234 /* A domain definition starts with <kernel>. */
 235 #define TOMOYO_ROOT_NAME                         "<kernel>"
 236 #define TOMOYO_ROOT_NAME_LEN                     (sizeof(TOMOYO_ROOT_NAME) - 1)
 237
 238 /* Index numbers for Access Controls. */
 239 #define TOMOYO_MAC_FOR_FILE                  0  /* domain_policy.conf */
 240 #define TOMOYO_MAX_ACCEPT_ENTRY              1
 241 #define TOMOYO_VERBOSE                       2
 242 #define TOMOYO_MAX_CONTROL_INDEX             3
 243
 244 /*
 245  * tomoyo_io_buffer is a structure which is used for reading and modifying
 246  * configuration via /sys/kernel/security/tomoyo/ interface.
 247  * It has many fields. ->read_var1 , ->read_var2 , ->write_var1 are used as
 248  * cursors.
 249  *
 250  * Since the content of /sys/kernel/security/tomoyo/domain_policy is a list of
 251  * "struct tomoyo_domain_info" entries and each "struct tomoyo_domain_info"
 252  * entry has a list of "struct tomoyo_acl_info", we need two cursors when
 253  * reading (one is for traversing tomoyo_domain_list and the other is for
 254  * traversing "struct tomoyo_acl_info"->acl_info_list ).
 255  *
 256  * If a line written to /sys/kernel/security/tomoyo/domain_policy starts with
 257  * "select ", TOMOYO seeks the cursor ->read_var1 and ->write_var1 to the
 258  * domain with the domainname specified by the rest of that line (NULL is set
 259  * if seek failed).
 260  * If a line written to /sys/kernel/security/tomoyo/domain_policy starts with
 261  * "delete ", TOMOYO deletes an entry or a domain specified by the rest of that
 262  * line (->write_var1 is set to NULL if a domain was deleted).
 263  * If a line written to /sys/kernel/security/tomoyo/domain_policy starts with
 264  * neither "select " nor "delete ", an entry or a domain specified by that line
 265  * is appended.
 266  */
 267 struct tomoyo_io_buffer {
 268         int (*read) (struct tomoyo_io_buffer *);
 269         int (*write) (struct tomoyo_io_buffer *);
 270         /* Exclusive lock for this structure.   */
 271         struct mutex io_sem;
 272         /* The position currently reading from. */
 273         struct list_head *read_var1;
 274         /* Extra variables for reading.         */
 275         struct list_head *read_var2;
 276         /* The position currently writing to.   */
 277         struct tomoyo_domain_info *write_var1;
 278         /* The step for reading.                */
 279         int read_step;
 280         /* Buffer for reading.                  */
 281         char *read_buf;
 282         /* EOF flag for reading.                */
 283         bool read_eof;
 284         /* Read domain ACL of specified PID?    */
 285         bool read_single_domain;
 286         /* Extra variable for reading.          */
 287         u8 read_bit;
 288         /* Bytes available for reading.         */
 289         int read_avail;
 290         /* Size of read buffer.                 */
 291         int readbuf_size;
 292         /* Buffer for writing.                  */
 293         char *write_buf;
 294         /* Bytes available for writing.         */
 295         int write_avail;
 296         /* Size of write buffer.                */
 297         int writebuf_size;
 298 };
 299
 300 /* Check whether the domain has too many ACL entries to hold. */
 301 bool tomoyo_domain_quota_is_ok(struct tomoyo_domain_info * const domain);
 302 /* Transactional sprintf() for policy dump. */
 303 bool tomoyo_io_printf(struct tomoyo_io_buffer *head, const char *fmt, ...)
 304         __attribute__ ((format(printf, 2, 3)));
 305 /* Check whether the domainname is correct. */
 306 bool tomoyo_is_correct_domain(const unsigned char *domainname,
 307                               const char *function);
 308 /* Check whether the token is correct. */
 309 bool tomoyo_is_correct_path(const char *filename, const s8 start_type,
 310                             const s8 pattern_type, const s8 end_type,
 311                             const char *function);
 312 /* Check whether the token can be a domainname. */
 313 bool tomoyo_is_domain_def(const unsigned char *buffer);
 314 /* Check whether the given filename matches the given pattern. */
 315 bool tomoyo_path_matches_pattern(const struct tomoyo_path_info *filename,
 316                                  const struct tomoyo_path_info *pattern);
 317 /* Read "alias" entry in exception policy. */
 318 bool tomoyo_read_alias_policy(struct tomoyo_io_buffer *head);
 319 /*
 320  * Read "initialize_domain" and "no_initialize_domain" entry
 321  * in exception policy.
 322  */
 323 bool tomoyo_read_domain_initializer_policy(struct tomoyo_io_buffer *head);
 324 /* Read "keep_domain" and "no_keep_domain" entry in exception policy. */
 325 bool tomoyo_read_domain_keeper_policy(struct tomoyo_io_buffer *head);
 326 /* Read "file_pattern" entry in exception policy. */
 327 bool tomoyo_read_file_pattern(struct tomoyo_io_buffer *head);
 328 /* Read "allow_read" entry in exception policy. */
 329 bool tomoyo_read_globally_readable_policy(struct tomoyo_io_buffer *head);
 330 /* Read "deny_rewrite" entry in exception policy. */
 331 bool tomoyo_read_no_rewrite_policy(struct tomoyo_io_buffer *head);
 332 /* Write domain policy violation warning message to console? */
 333 bool tomoyo_verbose_mode(const struct tomoyo_domain_info *domain);
 334 /* Convert double path operation to operation name. */
 335 const char *tomoyo_dp2keyword(const u8 operation);
 336 /* Get the last component of the given domainname. */
 337 const char *tomoyo_get_last_name(const struct tomoyo_domain_info *domain);
 338 /* Get warning message. */
 339 const char *tomoyo_get_msg(const bool is_enforce);
 340 /* Convert single path operation to operation name. */
 341 const char *tomoyo_sp2keyword(const u8 operation);
 342 /* Delete a domain. */
 343 int tomoyo_delete_domain(char *data);
 344 /* Create "alias" entry in exception policy. */
 345 int tomoyo_write_alias_policy(char *data, const bool is_delete);
 346 /*
 347  * Create "initialize_domain" and "no_initialize_domain" entry
 348  * in exception policy.
 349  */
 350 int tomoyo_write_domain_initializer_policy(char *data, const bool is_not,
 351                                            const bool is_delete);
 352 /* Create "keep_domain" and "no_keep_domain" entry in exception policy. */
 353 int tomoyo_write_domain_keeper_policy(char *data, const bool is_not,
 354                                       const bool is_delete);
 355 /*
 356  * Create "allow_read/write", "allow_execute", "allow_read", "allow_write",
 357  * "allow_create", "allow_unlink", "allow_mkdir", "allow_rmdir",
 358  * "allow_mkfifo", "allow_mksock", "allow_mkblock", "allow_mkchar",
 359  * "allow_truncate", "allow_symlink", "allow_rewrite", "allow_rename" and
 360  * "allow_link" entry in domain policy.
 361  */
 362 int tomoyo_write_file_policy(char *data, struct tomoyo_domain_info *domain,
 363                              const bool is_delete);
 364 /* Create "allow_read" entry in exception policy. */
 365 int tomoyo_write_globally_readable_policy(char *data, const bool is_delete);
 366 /* Create "deny_rewrite" entry in exception policy. */
 367 int tomoyo_write_no_rewrite_policy(char *data, const bool is_delete);
 368 /* Create "file_pattern" entry in exception policy. */
 369 int tomoyo_write_pattern_policy(char *data, const bool is_delete);
 370 /* Find a domain by the given name. */
 371 struct tomoyo_domain_info *tomoyo_find_domain(const char *domainname);
 372 /* Find or create a domain by the given name. */
 373 struct tomoyo_domain_info *tomoyo_find_or_assign_new_domain(const char *
 374                                                             domainname,
 375                                                             const u8 profile);
 376 /* Check mode for specified functionality. */
 377 unsigned int tomoyo_check_flags(const struct tomoyo_domain_info *domain,
 378                                 const u8 index);
 379 /* Allocate memory for structures. */
 380 void *tomoyo_alloc_acl_element(const u8 acl_type);
 381 /* Fill in "struct tomoyo_path_info" members. */
 382 void tomoyo_fill_path_info(struct tomoyo_path_info *ptr);
 383 /* Run policy loader when /sbin/init starts. */
 384 void tomoyo_load_policy(const char *filename);
 385 /* Change "struct tomoyo_domain_info"->flags. */
 386 void tomoyo_set_domain_flag(struct tomoyo_domain_info *domain,
 387                             const bool is_delete, const u8 flags);
 388
 389 /* strcmp() for "struct tomoyo_path_info" structure. */
 390 static inline bool tomoyo_pathcmp(const struct tomoyo_path_info *a,
 391                                   const struct tomoyo_path_info *b)
 392 {
 393         return a->hash != b->hash || strcmp(a->name, b->name);
 394 }
 395
 396 /* Get type of an ACL entry. */
 397 static inline u8 tomoyo_acl_type1(struct tomoyo_acl_info *ptr)
 398 {
 399         return ptr->type & ~TOMOYO_ACL_DELETED;
 400 }
 401
 402 /* Get type of an ACL entry. */
 403 static inline u8 tomoyo_acl_type2(struct tomoyo_acl_info *ptr)
 404 {
 405         return ptr->type;
 406 }
 407
 408 /**
 409  * tomoyo_is_valid - Check whether the character is a valid char.
 410  *
 411  * @c: The character to check.
 412  *
 413  * Returns true if @c is a valid character, false otherwise.
 414  */
 415 static inline bool tomoyo_is_valid(const unsigned char c)
 416 {
 417         return c > ' ' && c < 127;
 418 }
 419
 420 /**
 421  * tomoyo_is_invalid - Check whether the character is an invalid char.
 422  *
 423  * @c: The character to check.
 424  *
 425  * Returns true if @c is an invalid character, false otherwise.
 426  */
 427 static inline bool tomoyo_is_invalid(const unsigned char c)
 428 {
 429         return c && (c <= ' ' || c >= 127);
 430 }
 431
 432 /* The list for "struct tomoyo_domain_info". */
 433 extern struct list_head tomoyo_domain_list;
 434 extern struct rw_semaphore tomoyo_domain_list_lock;
 435
 436 /* Lock for domain->acl_info_list. */
 437 extern struct rw_semaphore tomoyo_domain_acl_info_list_lock;
 438
 439 /* Has /sbin/init started? */
 440 extern bool tomoyo_policy_loaded;
 441
 442 /* The kernel's domain. */
 443 extern struct tomoyo_domain_info tomoyo_kernel_domain;
 444
 445 /**
 446  * list_for_each_cookie - iterate over a list with cookie.
 447  * @pos:        the &struct list_head to use as a loop cursor.
 448  * @cookie:     the &struct list_head to use as a cookie.
 449  * @head:       the head for your list.
 450  *
 451  * Same with list_for_each() except that this primitive uses @cookie
 452  * so that we can continue iteration.
 453  * @cookie must be NULL when iteration starts, and @cookie will become
 454  * NULL when iteration finishes.
 455  */
 456 #define list_for_each_cookie(pos, cookie, head)                       \
 457         for (({ if (!cookie)                                          \
 458                                      cookie = head; }),               \
 459              pos = (cookie)->next;                                    \
 460              prefetch(pos->next), pos != (head) || ((cookie) = NULL); \
 461              (cookie) = pos, pos = pos->next)
 462
 463 #endif /* !defined(_SECURITY_TOMOYO_COMMON_H) */