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