1 /** 2 * eCryptfs: Linux filesystem encryption layer 3 * Kernel declarations. 4 * 5 * Copyright (C) 1997-2003 Erez Zadok 6 * Copyright (C) 2001-2003 Stony Brook University 7 * Copyright (C) 2004-2006 International Business Machines Corp. 8 * Author(s): Michael A. Halcrow <mahalcro@us.ibm.com> 9 * 10 * This program is free software; you can redistribute it and/or 11 * modify it under the terms of the GNU General Public License as 12 * published by the Free Software Foundation; either version 2 of the 13 * License, or (at your option) any later version. 14 * 15 * This program is distributed in the hope that it will be useful, but 16 * WITHOUT ANY WARRANTY; without even the implied warranty of 17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 18 * General Public License for more details. 19 * 20 * You should have received a copy of the GNU General Public License 21 * along with this program; if not, write to the Free Software 22 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 23 * 02111-1307, USA. 24 */ 25 26 #ifndef ECRYPTFS_KERNEL_H 27 #define ECRYPTFS_KERNEL_H 28 29 #include <keys/user-type.h> 30 #include <linux/fs.h> 31 #include <linux/fs_stack.h> 32 #include <linux/namei.h> 33 #include <linux/scatterlist.h> 34 35 /* Version verification for shared data structures w/ userspace */ 36 #define ECRYPTFS_VERSION_MAJOR 0x00 37 #define ECRYPTFS_VERSION_MINOR 0x04 38 #define ECRYPTFS_SUPPORTED_FILE_VERSION 0x01 39 /* These flags indicate which features are supported by the kernel 40 * module; userspace tools such as the mount helper read 41 * ECRYPTFS_VERSIONING_MASK from a sysfs handle in order to determine 42 * how to behave. */ 43 #define ECRYPTFS_VERSIONING_PASSPHRASE 0x00000001 44 #define ECRYPTFS_VERSIONING_PUBKEY 0x00000002 45 #define ECRYPTFS_VERSIONING_PLAINTEXT_PASSTHROUGH 0x00000004 46 #define ECRYPTFS_VERSIONING_POLICY 0x00000008 47 #define ECRYPTFS_VERSIONING_MASK (ECRYPTFS_VERSIONING_PASSPHRASE \ 48 | ECRYPTFS_VERSIONING_PLAINTEXT_PASSTHROUGH) 49 50 #define ECRYPTFS_MAX_PASSWORD_LENGTH 64 51 #define ECRYPTFS_MAX_PASSPHRASE_BYTES ECRYPTFS_MAX_PASSWORD_LENGTH 52 #define ECRYPTFS_SALT_SIZE 8 53 #define ECRYPTFS_SALT_SIZE_HEX (ECRYPTFS_SALT_SIZE*2) 54 /* The original signature size is only for what is stored on disk; all 55 * in-memory representations are expanded hex, so it better adapted to 56 * be passed around or referenced on the command line */ 57 #define ECRYPTFS_SIG_SIZE 8 58 #define ECRYPTFS_SIG_SIZE_HEX (ECRYPTFS_SIG_SIZE*2) 59 #define ECRYPTFS_PASSWORD_SIG_SIZE ECRYPTFS_SIG_SIZE_HEX 60 #define ECRYPTFS_MAX_KEY_BYTES 64 61 #define ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES 512 62 #define ECRYPTFS_DEFAULT_IV_BYTES 16 63 #define ECRYPTFS_FILE_VERSION 0x01 64 #define ECRYPTFS_DEFAULT_HEADER_EXTENT_SIZE 8192 65 #define ECRYPTFS_DEFAULT_EXTENT_SIZE 4096 66 #define ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE 8192 67 68 #define RFC2440_CIPHER_DES3_EDE 0x02 69 #define RFC2440_CIPHER_CAST_5 0x03 70 #define RFC2440_CIPHER_BLOWFISH 0x04 71 #define RFC2440_CIPHER_AES_128 0x07 72 #define RFC2440_CIPHER_AES_192 0x08 73 #define RFC2440_CIPHER_AES_256 0x09 74 #define RFC2440_CIPHER_TWOFISH 0x0a 75 #define RFC2440_CIPHER_CAST_6 0x0b 76 77 #define ECRYPTFS_SET_FLAG(flag_bit_vector, flag) (flag_bit_vector |= (flag)) 78 #define ECRYPTFS_CLEAR_FLAG(flag_bit_vector, flag) (flag_bit_vector &= ~(flag)) 79 #define ECRYPTFS_CHECK_FLAG(flag_bit_vector, flag) (flag_bit_vector & (flag)) 80 81 /** 82 * For convenience, we may need to pass around the encrypted session 83 * key between kernel and userspace because the authentication token 84 * may not be extractable. For example, the TPM may not release the 85 * private key, instead requiring the encrypted data and returning the 86 * decrypted data. 87 */ 88 struct ecryptfs_session_key { 89 #define ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT 0x00000001 90 #define ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT 0x00000002 91 #define ECRYPTFS_CONTAINS_DECRYPTED_KEY 0x00000004 92 #define ECRYPTFS_CONTAINS_ENCRYPTED_KEY 0x00000008 93 u32 flags; 94 u32 encrypted_key_size; 95 u32 decrypted_key_size; 96 u8 encrypted_key[ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES]; 97 u8 decrypted_key[ECRYPTFS_MAX_KEY_BYTES]; 98 }; 99 100 struct ecryptfs_password { 101 u32 password_bytes; 102 s32 hash_algo; 103 u32 hash_iterations; 104 u32 session_key_encryption_key_bytes; 105 #define ECRYPTFS_PERSISTENT_PASSWORD 0x01 106 #define ECRYPTFS_SESSION_KEY_ENCRYPTION_KEY_SET 0x02 107 u32 flags; 108 /* Iterated-hash concatenation of salt and passphrase */ 109 u8 session_key_encryption_key[ECRYPTFS_MAX_KEY_BYTES]; 110 u8 signature[ECRYPTFS_PASSWORD_SIG_SIZE + 1]; 111 /* Always in expanded hex */ 112 u8 salt[ECRYPTFS_SALT_SIZE]; 113 }; 114 115 enum ecryptfs_token_types {ECRYPTFS_PASSWORD, ECRYPTFS_PRIVATE_KEY}; 116 117 /* May be a password or a private key */ 118 struct ecryptfs_auth_tok { 119 u16 version; /* 8-bit major and 8-bit minor */ 120 u16 token_type; 121 u32 flags; 122 struct ecryptfs_session_key session_key; 123 u8 reserved[32]; 124 union { 125 struct ecryptfs_password password; 126 /* Private key is in future eCryptfs releases */ 127 } token; 128 } __attribute__ ((packed)); 129 130 void ecryptfs_dump_auth_tok(struct ecryptfs_auth_tok *auth_tok); 131 extern void ecryptfs_to_hex(char *dst, char *src, size_t src_size); 132 extern void ecryptfs_from_hex(char *dst, char *src, int dst_size); 133 134 struct ecryptfs_key_record { 135 unsigned char type; 136 size_t enc_key_size; 137 unsigned char sig[ECRYPTFS_SIG_SIZE]; 138 unsigned char enc_key[ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES]; 139 }; 140 141 struct ecryptfs_auth_tok_list { 142 struct ecryptfs_auth_tok *auth_tok; 143 struct list_head list; 144 }; 145 146 struct ecryptfs_crypt_stat; 147 struct ecryptfs_mount_crypt_stat; 148 149 struct ecryptfs_page_crypt_context { 150 struct page *page; 151 #define ECRYPTFS_PREPARE_COMMIT_MODE 0 152 #define ECRYPTFS_WRITEPAGE_MODE 1 153 unsigned int mode; 154 union { 155 struct file *lower_file; 156 struct writeback_control *wbc; 157 } param; 158 }; 159 160 static inline struct ecryptfs_auth_tok * 161 ecryptfs_get_key_payload_data(struct key *key) 162 { 163 return (struct ecryptfs_auth_tok *) 164 (((struct user_key_payload*)key->payload.data)->data); 165 } 166 167 #define ECRYPTFS_SUPER_MAGIC 0xf15f 168 #define ECRYPTFS_MAX_KEYSET_SIZE 1024 169 #define ECRYPTFS_MAX_CIPHER_NAME_SIZE 32 170 #define ECRYPTFS_MAX_NUM_ENC_KEYS 64 171 #define ECRYPTFS_MAX_NUM_KEYSIGS 2 /* TODO: Make this a linked list */ 172 #define ECRYPTFS_MAX_IV_BYTES 16 /* 128 bits */ 173 #define ECRYPTFS_SALT_BYTES 2 174 #define MAGIC_ECRYPTFS_MARKER 0x3c81b7f5 175 #define MAGIC_ECRYPTFS_MARKER_SIZE_BYTES 8 /* 4*2 */ 176 #define ECRYPTFS_FILE_SIZE_BYTES 8 177 #define ECRYPTFS_DEFAULT_CIPHER "aes" 178 #define ECRYPTFS_DEFAULT_KEY_BYTES 16 179 #define ECRYPTFS_DEFAULT_CHAINING_MODE CRYPTO_TFM_MODE_CBC 180 #define ECRYPTFS_DEFAULT_HASH "md5" 181 #define ECRYPTFS_TAG_3_PACKET_TYPE 0x8C 182 #define ECRYPTFS_TAG_11_PACKET_TYPE 0xED 183 #define MD5_DIGEST_SIZE 16 184 185 /** 186 * This is the primary struct associated with each encrypted file. 187 * 188 * TODO: cache align/pack? 189 */ 190 struct ecryptfs_crypt_stat { 191 #define ECRYPTFS_STRUCT_INITIALIZED 0x00000001 192 #define ECRYPTFS_POLICY_APPLIED 0x00000002 193 #define ECRYPTFS_NEW_FILE 0x00000004 194 #define ECRYPTFS_ENCRYPTED 0x00000008 195 #define ECRYPTFS_SECURITY_WARNING 0x00000010 196 #define ECRYPTFS_ENABLE_HMAC 0x00000020 197 #define ECRYPTFS_ENCRYPT_IV_PAGES 0x00000040 198 #define ECRYPTFS_KEY_VALID 0x00000080 199 u32 flags; 200 unsigned int file_version; 201 size_t iv_bytes; 202 size_t num_keysigs; 203 size_t header_extent_size; 204 size_t num_header_extents_at_front; 205 size_t extent_size; /* Data extent size; default is 4096 */ 206 size_t key_size; 207 size_t extent_shift; 208 unsigned int extent_mask; 209 struct ecryptfs_mount_crypt_stat *mount_crypt_stat; 210 struct crypto_blkcipher *tfm; 211 struct crypto_hash *hash_tfm; /* Crypto context for generating 212 * the initialization vectors */ 213 unsigned char cipher[ECRYPTFS_MAX_CIPHER_NAME_SIZE]; 214 unsigned char key[ECRYPTFS_MAX_KEY_BYTES]; 215 unsigned char root_iv[ECRYPTFS_MAX_IV_BYTES]; 216 unsigned char keysigs[ECRYPTFS_MAX_NUM_KEYSIGS][ECRYPTFS_SIG_SIZE_HEX]; 217 struct mutex cs_tfm_mutex; 218 struct mutex cs_hash_tfm_mutex; 219 struct mutex cs_mutex; 220 }; 221 222 /* inode private data. */ 223 struct ecryptfs_inode_info { 224 struct inode vfs_inode; 225 struct inode *wii_inode; 226 struct ecryptfs_crypt_stat crypt_stat; 227 }; 228 229 /* dentry private data. Each dentry must keep track of a lower 230 * vfsmount too. */ 231 struct ecryptfs_dentry_info { 232 struct path lower_path; 233 struct ecryptfs_crypt_stat *crypt_stat; 234 }; 235 236 /** 237 * This struct is to enable a mount-wide passphrase/salt combo. This 238 * is more or less a stopgap to provide similar functionality to other 239 * crypto filesystems like EncFS or CFS until full policy support is 240 * implemented in eCryptfs. 241 */ 242 struct ecryptfs_mount_crypt_stat { 243 /* Pointers to memory we do not own, do not free these */ 244 #define ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED 0x00000001 245 u32 flags; 246 struct ecryptfs_auth_tok *global_auth_tok; 247 struct key *global_auth_tok_key; 248 size_t global_default_cipher_key_size; 249 struct crypto_blkcipher *global_key_tfm; 250 struct mutex global_key_tfm_mutex; 251 unsigned char global_default_cipher_name[ECRYPTFS_MAX_CIPHER_NAME_SIZE 252 + 1]; 253 unsigned char global_auth_tok_sig[ECRYPTFS_SIG_SIZE_HEX + 1]; 254 }; 255 256 /* superblock private data. */ 257 struct ecryptfs_sb_info { 258 struct super_block *wsi_sb; 259 struct ecryptfs_mount_crypt_stat mount_crypt_stat; 260 }; 261 262 /* file private data. */ 263 struct ecryptfs_file_info { 264 struct file *wfi_file; 265 struct ecryptfs_crypt_stat *crypt_stat; 266 }; 267 268 /* auth_tok <=> encrypted_session_key mappings */ 269 struct ecryptfs_auth_tok_list_item { 270 unsigned char encrypted_session_key[ECRYPTFS_MAX_KEY_BYTES]; 271 struct list_head list; 272 struct ecryptfs_auth_tok auth_tok; 273 }; 274 275 static inline struct ecryptfs_file_info * 276 ecryptfs_file_to_private(struct file *file) 277 { 278 return (struct ecryptfs_file_info *)file->private_data; 279 } 280 281 static inline void 282 ecryptfs_set_file_private(struct file *file, 283 struct ecryptfs_file_info *file_info) 284 { 285 file->private_data = file_info; 286 } 287 288 static inline struct file *ecryptfs_file_to_lower(struct file *file) 289 { 290 return ((struct ecryptfs_file_info *)file->private_data)->wfi_file; 291 } 292 293 static inline void 294 ecryptfs_set_file_lower(struct file *file, struct file *lower_file) 295 { 296 ((struct ecryptfs_file_info *)file->private_data)->wfi_file = 297 lower_file; 298 } 299 300 static inline struct ecryptfs_inode_info * 301 ecryptfs_inode_to_private(struct inode *inode) 302 { 303 return container_of(inode, struct ecryptfs_inode_info, vfs_inode); 304 } 305 306 static inline struct inode *ecryptfs_inode_to_lower(struct inode *inode) 307 { 308 return ecryptfs_inode_to_private(inode)->wii_inode; 309 } 310 311 static inline void 312 ecryptfs_set_inode_lower(struct inode *inode, struct inode *lower_inode) 313 { 314 ecryptfs_inode_to_private(inode)->wii_inode = lower_inode; 315 } 316 317 static inline struct ecryptfs_sb_info * 318 ecryptfs_superblock_to_private(struct super_block *sb) 319 { 320 return (struct ecryptfs_sb_info *)sb->s_fs_info; 321 } 322 323 static inline void 324 ecryptfs_set_superblock_private(struct super_block *sb, 325 struct ecryptfs_sb_info *sb_info) 326 { 327 sb->s_fs_info = sb_info; 328 } 329 330 static inline struct super_block * 331 ecryptfs_superblock_to_lower(struct super_block *sb) 332 { 333 return ((struct ecryptfs_sb_info *)sb->s_fs_info)->wsi_sb; 334 } 335 336 static inline void 337 ecryptfs_set_superblock_lower(struct super_block *sb, 338 struct super_block *lower_sb) 339 { 340 ((struct ecryptfs_sb_info *)sb->s_fs_info)->wsi_sb = lower_sb; 341 } 342 343 static inline struct ecryptfs_dentry_info * 344 ecryptfs_dentry_to_private(struct dentry *dentry) 345 { 346 return (struct ecryptfs_dentry_info *)dentry->d_fsdata; 347 } 348 349 static inline void 350 ecryptfs_set_dentry_private(struct dentry *dentry, 351 struct ecryptfs_dentry_info *dentry_info) 352 { 353 dentry->d_fsdata = dentry_info; 354 } 355 356 static inline struct dentry * 357 ecryptfs_dentry_to_lower(struct dentry *dentry) 358 { 359 return ((struct ecryptfs_dentry_info *)dentry->d_fsdata)->lower_path.dentry; 360 } 361 362 static inline void 363 ecryptfs_set_dentry_lower(struct dentry *dentry, struct dentry *lower_dentry) 364 { 365 ((struct ecryptfs_dentry_info *)dentry->d_fsdata)->lower_path.dentry = 366 lower_dentry; 367 } 368 369 static inline struct vfsmount * 370 ecryptfs_dentry_to_lower_mnt(struct dentry *dentry) 371 { 372 return ((struct ecryptfs_dentry_info *)dentry->d_fsdata)->lower_path.mnt; 373 } 374 375 static inline void 376 ecryptfs_set_dentry_lower_mnt(struct dentry *dentry, struct vfsmount *lower_mnt) 377 { 378 ((struct ecryptfs_dentry_info *)dentry->d_fsdata)->lower_path.mnt = 379 lower_mnt; 380 } 381 382 #define ecryptfs_printk(type, fmt, arg...) \ 383 __ecryptfs_printk(type "%s: " fmt, __FUNCTION__, ## arg); 384 void __ecryptfs_printk(const char *fmt, ...); 385 386 extern const struct file_operations ecryptfs_main_fops; 387 extern const struct file_operations ecryptfs_dir_fops; 388 extern struct inode_operations ecryptfs_main_iops; 389 extern struct inode_operations ecryptfs_dir_iops; 390 extern struct inode_operations ecryptfs_symlink_iops; 391 extern struct super_operations ecryptfs_sops; 392 extern struct dentry_operations ecryptfs_dops; 393 extern struct address_space_operations ecryptfs_aops; 394 extern int ecryptfs_verbosity; 395 396 extern struct kmem_cache *ecryptfs_auth_tok_list_item_cache; 397 extern struct kmem_cache *ecryptfs_file_info_cache; 398 extern struct kmem_cache *ecryptfs_dentry_info_cache; 399 extern struct kmem_cache *ecryptfs_inode_info_cache; 400 extern struct kmem_cache *ecryptfs_sb_info_cache; 401 extern struct kmem_cache *ecryptfs_header_cache_0; 402 extern struct kmem_cache *ecryptfs_header_cache_1; 403 extern struct kmem_cache *ecryptfs_header_cache_2; 404 extern struct kmem_cache *ecryptfs_lower_page_cache; 405 406 int ecryptfs_interpose(struct dentry *hidden_dentry, 407 struct dentry *this_dentry, struct super_block *sb, 408 int flag); 409 int ecryptfs_fill_zeros(struct file *file, loff_t new_length); 410 int ecryptfs_decode_filename(struct ecryptfs_crypt_stat *crypt_stat, 411 const char *name, int length, 412 char **decrypted_name); 413 int ecryptfs_encode_filename(struct ecryptfs_crypt_stat *crypt_stat, 414 const char *name, int length, 415 char **encoded_name); 416 struct dentry *ecryptfs_lower_dentry(struct dentry *this_dentry); 417 void ecryptfs_dump_hex(char *data, int bytes); 418 int virt_to_scatterlist(const void *addr, int size, struct scatterlist *sg, 419 int sg_size); 420 int ecryptfs_compute_root_iv(struct ecryptfs_crypt_stat *crypt_stat); 421 void ecryptfs_rotate_iv(unsigned char *iv); 422 void ecryptfs_init_crypt_stat(struct ecryptfs_crypt_stat *crypt_stat); 423 void ecryptfs_destruct_crypt_stat(struct ecryptfs_crypt_stat *crypt_stat); 424 void ecryptfs_destruct_mount_crypt_stat( 425 struct ecryptfs_mount_crypt_stat *mount_crypt_stat); 426 int ecryptfs_init_crypt_ctx(struct ecryptfs_crypt_stat *crypt_stat); 427 int ecryptfs_crypto_api_algify_cipher_name(char **algified_name, 428 char *cipher_name, 429 char *chaining_modifier); 430 int ecryptfs_write_inode_size_to_header(struct file *lower_file, 431 struct inode *lower_inode, 432 struct inode *inode); 433 int ecryptfs_get_lower_page(struct page **lower_page, struct inode *lower_inode, 434 struct file *lower_file, 435 unsigned long lower_page_index, int byte_offset, 436 int region_bytes); 437 int 438 ecryptfs_commit_lower_page(struct page *lower_page, struct inode *lower_inode, 439 struct file *lower_file, int byte_offset, 440 int region_size); 441 int ecryptfs_copy_page_to_lower(struct page *page, struct inode *lower_inode, 442 struct file *lower_file); 443 int ecryptfs_do_readpage(struct file *file, struct page *page, 444 pgoff_t lower_page_index); 445 int ecryptfs_grab_and_map_lower_page(struct page **lower_page, 446 char **lower_virt, 447 struct inode *lower_inode, 448 unsigned long lower_page_index); 449 int ecryptfs_writepage_and_release_lower_page(struct page *lower_page, 450 struct inode *lower_inode, 451 struct writeback_control *wbc); 452 int ecryptfs_encrypt_page(struct ecryptfs_page_crypt_context *ctx); 453 int ecryptfs_decrypt_page(struct file *file, struct page *page); 454 int ecryptfs_write_headers(struct dentry *ecryptfs_dentry, 455 struct file *lower_file); 456 int ecryptfs_write_headers_virt(char *page_virt, 457 struct ecryptfs_crypt_stat *crypt_stat, 458 struct dentry *ecryptfs_dentry); 459 int ecryptfs_read_headers(struct dentry *ecryptfs_dentry, 460 struct file *lower_file); 461 int ecryptfs_new_file_context(struct dentry *ecryptfs_dentry); 462 int contains_ecryptfs_marker(char *data); 463 int ecryptfs_read_header_region(char *data, struct dentry *dentry, 464 struct vfsmount *mnt); 465 u16 ecryptfs_code_for_cipher_string(struct ecryptfs_crypt_stat *crypt_stat); 466 int ecryptfs_cipher_code_to_string(char *str, u16 cipher_code); 467 void ecryptfs_set_default_sizes(struct ecryptfs_crypt_stat *crypt_stat); 468 int ecryptfs_generate_key_packet_set(char *dest_base, 469 struct ecryptfs_crypt_stat *crypt_stat, 470 struct dentry *ecryptfs_dentry, 471 size_t *len, size_t max); 472 int process_request_key_err(long err_code); 473 int 474 ecryptfs_parse_packet_set(struct ecryptfs_crypt_stat *crypt_stat, 475 unsigned char *src, struct dentry *ecryptfs_dentry); 476 int ecryptfs_truncate(struct dentry *dentry, loff_t new_length); 477 int 478 ecryptfs_process_cipher(struct crypto_blkcipher **key_tfm, char *cipher_name, 479 size_t *key_size); 480 int ecryptfs_inode_test(struct inode *inode, void *candidate_lower_inode); 481 int ecryptfs_inode_set(struct inode *inode, void *lower_inode); 482 void ecryptfs_init_inode(struct inode *inode, struct inode *lower_inode); 483 int ecryptfs_open_lower_file(struct file **lower_file, 484 struct dentry *lower_dentry, 485 struct vfsmount *lower_mnt, int flags); 486 int ecryptfs_close_lower_file(struct file *lower_file); 487 488 #endif /* #ifndef ECRYPTFS_KERNEL_H */ 489