| 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
| 2 | /* |
| 3 | * eCryptfs: Linux filesystem encryption layer |
| 4 | * |
| 5 | * Copyright (C) 1997-2004 Erez Zadok |
| 6 | * Copyright (C) 2001-2004 Stony Brook University |
| 7 | * Copyright (C) 2004-2007 International Business Machines Corp. |
| 8 | * Author(s): Michael A. Halcrow <mahalcro@us.ibm.com> |
| 9 | * Michael C. Thompson <mcthomps@us.ibm.com> |
| 10 | */ |
| 11 | |
| 12 | #include <crypto/hash.h> |
| 13 | #include <crypto/skcipher.h> |
| 14 | #include <linux/fs.h> |
| 15 | #include <linux/mount.h> |
| 16 | #include <linux/pagemap.h> |
| 17 | #include <linux/random.h> |
| 18 | #include <linux/compiler.h> |
| 19 | #include <linux/key.h> |
| 20 | #include <linux/namei.h> |
| 21 | #include <linux/file.h> |
| 22 | #include <linux/scatterlist.h> |
| 23 | #include <linux/slab.h> |
| 24 | #include <asm/unaligned.h> |
| 25 | #include <linux/kernel.h> |
| 26 | #include <linux/xattr.h> |
| 27 | #include "ecryptfs_kernel.h" |
| 28 | |
| 29 | #define DECRYPT 0 |
| 30 | #define ENCRYPT 1 |
| 31 | |
| 32 | /** |
| 33 | * ecryptfs_from_hex |
| 34 | * @dst: Buffer to take the bytes from src hex; must be at least of |
| 35 | * size (src_size / 2) |
| 36 | * @src: Buffer to be converted from a hex string representation to raw value |
| 37 | * @dst_size: size of dst buffer, or number of hex characters pairs to convert |
| 38 | */ |
| 39 | void ecryptfs_from_hex(char *dst, char *src, int dst_size) |
| 40 | { |
| 41 | int x; |
| 42 | char tmp[3] = { 0, }; |
| 43 | |
| 44 | for (x = 0; x < dst_size; x++) { |
| 45 | tmp[0] = src[x * 2]; |
| 46 | tmp[1] = src[x * 2 + 1]; |
| 47 | dst[x] = (unsigned char)simple_strtol(tmp, NULL, 16); |
| 48 | } |
| 49 | } |
| 50 | |
| 51 | /** |
| 52 | * ecryptfs_calculate_md5 - calculates the md5 of @src |
| 53 | * @dst: Pointer to 16 bytes of allocated memory |
| 54 | * @crypt_stat: Pointer to crypt_stat struct for the current inode |
| 55 | * @src: Data to be md5'd |
| 56 | * @len: Length of @src |
| 57 | * |
| 58 | * Uses the allocated crypto context that crypt_stat references to |
| 59 | * generate the MD5 sum of the contents of src. |
| 60 | */ |
| 61 | static int ecryptfs_calculate_md5(char *dst, |
| 62 | struct ecryptfs_crypt_stat *crypt_stat, |
| 63 | char *src, int len) |
| 64 | { |
| 65 | int rc = crypto_shash_tfm_digest(crypt_stat->hash_tfm, src, len, dst); |
| 66 | |
| 67 | if (rc) { |
| 68 | printk(KERN_ERR |
| 69 | "%s: Error computing crypto hash; rc = [%d]\n", |
| 70 | __func__, rc); |
| 71 | goto out; |
| 72 | } |
| 73 | out: |
| 74 | return rc; |
| 75 | } |
| 76 | |
| 77 | static int ecryptfs_crypto_api_algify_cipher_name(char **algified_name, |
| 78 | char *cipher_name, |
| 79 | char *chaining_modifier) |
| 80 | { |
| 81 | int cipher_name_len = strlen(cipher_name); |
| 82 | int chaining_modifier_len = strlen(chaining_modifier); |
| 83 | int algified_name_len; |
| 84 | int rc; |
| 85 | |
| 86 | algified_name_len = (chaining_modifier_len + cipher_name_len + 3); |
| 87 | (*algified_name) = kmalloc(algified_name_len, GFP_KERNEL); |
| 88 | if (!(*algified_name)) { |
| 89 | rc = -ENOMEM; |
| 90 | goto out; |
| 91 | } |
| 92 | snprintf((*algified_name), algified_name_len, "%s(%s)", |
| 93 | chaining_modifier, cipher_name); |
| 94 | rc = 0; |
| 95 | out: |
| 96 | return rc; |
| 97 | } |
| 98 | |
| 99 | /** |
| 100 | * ecryptfs_derive_iv |
| 101 | * @iv: destination for the derived iv vale |
| 102 | * @crypt_stat: Pointer to crypt_stat struct for the current inode |
| 103 | * @offset: Offset of the extent whose IV we are to derive |
| 104 | * |
| 105 | * Generate the initialization vector from the given root IV and page |
| 106 | * offset. |
| 107 | * |
| 108 | * Returns zero on success; non-zero on error. |
| 109 | */ |
| 110 | int ecryptfs_derive_iv(char *iv, struct ecryptfs_crypt_stat *crypt_stat, |
| 111 | loff_t offset) |
| 112 | { |
| 113 | int rc = 0; |
| 114 | char dst[MD5_DIGEST_SIZE]; |
| 115 | char src[ECRYPTFS_MAX_IV_BYTES + 16]; |
| 116 | |
| 117 | if (unlikely(ecryptfs_verbosity > 0)) { |
| 118 | ecryptfs_printk(KERN_DEBUG, "root iv:\n"); |
| 119 | ecryptfs_dump_hex(crypt_stat->root_iv, crypt_stat->iv_bytes); |
| 120 | } |
| 121 | /* TODO: It is probably secure to just cast the least |
| 122 | * significant bits of the root IV into an unsigned long and |
| 123 | * add the offset to that rather than go through all this |
| 124 | * hashing business. -Halcrow */ |
| 125 | memcpy(src, crypt_stat->root_iv, crypt_stat->iv_bytes); |
| 126 | memset((src + crypt_stat->iv_bytes), 0, 16); |
| 127 | snprintf((src + crypt_stat->iv_bytes), 16, "%lld", offset); |
| 128 | if (unlikely(ecryptfs_verbosity > 0)) { |
| 129 | ecryptfs_printk(KERN_DEBUG, "source:\n"); |
| 130 | ecryptfs_dump_hex(src, (crypt_stat->iv_bytes + 16)); |
| 131 | } |
| 132 | rc = ecryptfs_calculate_md5(dst, crypt_stat, src, |
| 133 | (crypt_stat->iv_bytes + 16)); |
| 134 | if (rc) { |
| 135 | ecryptfs_printk(KERN_WARNING, "Error attempting to compute " |
| 136 | "MD5 while generating IV for a page\n"); |
| 137 | goto out; |
| 138 | } |
| 139 | memcpy(iv, dst, crypt_stat->iv_bytes); |
| 140 | if (unlikely(ecryptfs_verbosity > 0)) { |
| 141 | ecryptfs_printk(KERN_DEBUG, "derived iv:\n"); |
| 142 | ecryptfs_dump_hex(iv, crypt_stat->iv_bytes); |
| 143 | } |
| 144 | out: |
| 145 | return rc; |
| 146 | } |
| 147 | |
| 148 | /** |
| 149 | * ecryptfs_init_crypt_stat |
| 150 | * @crypt_stat: Pointer to the crypt_stat struct to initialize. |
| 151 | * |
| 152 | * Initialize the crypt_stat structure. |
| 153 | */ |
| 154 | int ecryptfs_init_crypt_stat(struct ecryptfs_crypt_stat *crypt_stat) |
| 155 | { |
| 156 | struct crypto_shash *tfm; |
| 157 | int rc; |
| 158 | |
| 159 | tfm = crypto_alloc_shash(ECRYPTFS_DEFAULT_HASH, 0, 0); |
| 160 | if (IS_ERR(tfm)) { |
| 161 | rc = PTR_ERR(tfm); |
| 162 | ecryptfs_printk(KERN_ERR, "Error attempting to " |
| 163 | "allocate crypto context; rc = [%d]\n", |
| 164 | rc); |
| 165 | return rc; |
| 166 | } |
| 167 | |
| 168 | memset((void *)crypt_stat, 0, sizeof(struct ecryptfs_crypt_stat)); |
| 169 | INIT_LIST_HEAD(&crypt_stat->keysig_list); |
| 170 | mutex_init(&crypt_stat->keysig_list_mutex); |
| 171 | mutex_init(&crypt_stat->cs_mutex); |
| 172 | mutex_init(&crypt_stat->cs_tfm_mutex); |
| 173 | crypt_stat->hash_tfm = tfm; |
| 174 | crypt_stat->flags |= ECRYPTFS_STRUCT_INITIALIZED; |
| 175 | |
| 176 | return 0; |
| 177 | } |
| 178 | |
| 179 | /** |
| 180 | * ecryptfs_destroy_crypt_stat |
| 181 | * @crypt_stat: Pointer to the crypt_stat struct to initialize. |
| 182 | * |
| 183 | * Releases all memory associated with a crypt_stat struct. |
| 184 | */ |
| 185 | void ecryptfs_destroy_crypt_stat(struct ecryptfs_crypt_stat *crypt_stat) |
| 186 | { |
| 187 | struct ecryptfs_key_sig *key_sig, *key_sig_tmp; |
| 188 | |
| 189 | crypto_free_skcipher(crypt_stat->tfm); |
| 190 | crypto_free_shash(crypt_stat->hash_tfm); |
| 191 | list_for_each_entry_safe(key_sig, key_sig_tmp, |
| 192 | &crypt_stat->keysig_list, crypt_stat_list) { |
| 193 | list_del(&key_sig->crypt_stat_list); |
| 194 | kmem_cache_free(ecryptfs_key_sig_cache, key_sig); |
| 195 | } |
| 196 | memset(crypt_stat, 0, sizeof(struct ecryptfs_crypt_stat)); |
| 197 | } |
| 198 | |
| 199 | void ecryptfs_destroy_mount_crypt_stat( |
| 200 | struct ecryptfs_mount_crypt_stat *mount_crypt_stat) |
| 201 | { |
| 202 | struct ecryptfs_global_auth_tok *auth_tok, *auth_tok_tmp; |
| 203 | |
| 204 | if (!(mount_crypt_stat->flags & ECRYPTFS_MOUNT_CRYPT_STAT_INITIALIZED)) |
| 205 | return; |
| 206 | mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex); |
| 207 | list_for_each_entry_safe(auth_tok, auth_tok_tmp, |
| 208 | &mount_crypt_stat->global_auth_tok_list, |
| 209 | mount_crypt_stat_list) { |
| 210 | list_del(&auth_tok->mount_crypt_stat_list); |
| 211 | if (!(auth_tok->flags & ECRYPTFS_AUTH_TOK_INVALID)) |
| 212 | key_put(auth_tok->global_auth_tok_key); |
| 213 | kmem_cache_free(ecryptfs_global_auth_tok_cache, auth_tok); |
| 214 | } |
| 215 | mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex); |
| 216 | memset(mount_crypt_stat, 0, sizeof(struct ecryptfs_mount_crypt_stat)); |
| 217 | } |
| 218 | |
| 219 | /** |
| 220 | * virt_to_scatterlist |
| 221 | * @addr: Virtual address |
| 222 | * @size: Size of data; should be an even multiple of the block size |
| 223 | * @sg: Pointer to scatterlist array; set to NULL to obtain only |
| 224 | * the number of scatterlist structs required in array |
| 225 | * @sg_size: Max array size |
| 226 | * |
| 227 | * Fills in a scatterlist array with page references for a passed |
| 228 | * virtual address. |
| 229 | * |
| 230 | * Returns the number of scatterlist structs in array used |
| 231 | */ |
| 232 | int virt_to_scatterlist(const void *addr, int size, struct scatterlist *sg, |
| 233 | int sg_size) |
| 234 | { |
| 235 | int i = 0; |
| 236 | struct page *pg; |
| 237 | int offset; |
| 238 | int remainder_of_page; |
| 239 | |
| 240 | sg_init_table(sg, sg_size); |
| 241 | |
| 242 | while (size > 0 && i < sg_size) { |
| 243 | pg = virt_to_page(addr); |
| 244 | offset = offset_in_page(addr); |
| 245 | sg_set_page(&sg[i], pg, 0, offset); |
| 246 | remainder_of_page = PAGE_SIZE - offset; |
| 247 | if (size >= remainder_of_page) { |
| 248 | sg[i].length = remainder_of_page; |
| 249 | addr += remainder_of_page; |
| 250 | size -= remainder_of_page; |
| 251 | } else { |
| 252 | sg[i].length = size; |
| 253 | addr += size; |
| 254 | size = 0; |
| 255 | } |
| 256 | i++; |
| 257 | } |
| 258 | if (size > 0) |
| 259 | return -ENOMEM; |
| 260 | return i; |
| 261 | } |
| 262 | |
| 263 | /** |
| 264 | * crypt_scatterlist |
| 265 | * @crypt_stat: Pointer to the crypt_stat struct to initialize. |
| 266 | * @dst_sg: Destination of the data after performing the crypto operation |
| 267 | * @src_sg: Data to be encrypted or decrypted |
| 268 | * @size: Length of data |
| 269 | * @iv: IV to use |
| 270 | * @op: ENCRYPT or DECRYPT to indicate the desired operation |
| 271 | * |
| 272 | * Returns the number of bytes encrypted or decrypted; negative value on error |
| 273 | */ |
| 274 | static int crypt_scatterlist(struct ecryptfs_crypt_stat *crypt_stat, |
| 275 | struct scatterlist *dst_sg, |
| 276 | struct scatterlist *src_sg, int size, |
| 277 | unsigned char *iv, int op) |
| 278 | { |
| 279 | struct skcipher_request *req = NULL; |
| 280 | DECLARE_CRYPTO_WAIT(ecr); |
| 281 | int rc = 0; |
| 282 | |
| 283 | if (unlikely(ecryptfs_verbosity > 0)) { |
| 284 | ecryptfs_printk(KERN_DEBUG, "Key size [%zd]; key:\n", |
| 285 | crypt_stat->key_size); |
| 286 | ecryptfs_dump_hex(crypt_stat->key, |
| 287 | crypt_stat->key_size); |
| 288 | } |
| 289 | |
| 290 | mutex_lock(&crypt_stat->cs_tfm_mutex); |
| 291 | req = skcipher_request_alloc(crypt_stat->tfm, GFP_NOFS); |
| 292 | if (!req) { |
| 293 | mutex_unlock(&crypt_stat->cs_tfm_mutex); |
| 294 | rc = -ENOMEM; |
| 295 | goto out; |
| 296 | } |
| 297 | |
| 298 | skcipher_request_set_callback(req, |
| 299 | CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP, |
| 300 | crypto_req_done, &ecr); |
| 301 | /* Consider doing this once, when the file is opened */ |
| 302 | if (!(crypt_stat->flags & ECRYPTFS_KEY_SET)) { |
| 303 | rc = crypto_skcipher_setkey(crypt_stat->tfm, crypt_stat->key, |
| 304 | crypt_stat->key_size); |
| 305 | if (rc) { |
| 306 | ecryptfs_printk(KERN_ERR, |
| 307 | "Error setting key; rc = [%d]\n", |
| 308 | rc); |
| 309 | mutex_unlock(&crypt_stat->cs_tfm_mutex); |
| 310 | rc = -EINVAL; |
| 311 | goto out; |
| 312 | } |
| 313 | crypt_stat->flags |= ECRYPTFS_KEY_SET; |
| 314 | } |
| 315 | mutex_unlock(&crypt_stat->cs_tfm_mutex); |
| 316 | skcipher_request_set_crypt(req, src_sg, dst_sg, size, iv); |
| 317 | rc = op == ENCRYPT ? crypto_skcipher_encrypt(req) : |
| 318 | crypto_skcipher_decrypt(req); |
| 319 | rc = crypto_wait_req(rc, &ecr); |
| 320 | out: |
| 321 | skcipher_request_free(req); |
| 322 | return rc; |
| 323 | } |
| 324 | |
| 325 | /* |
| 326 | * lower_offset_for_page |
| 327 | * |
| 328 | * Convert an eCryptfs page index into a lower byte offset |
| 329 | */ |
| 330 | static loff_t lower_offset_for_page(struct ecryptfs_crypt_stat *crypt_stat, |
| 331 | struct page *page) |
| 332 | { |
| 333 | return ecryptfs_lower_header_size(crypt_stat) + |
| 334 | ((loff_t)page->index << PAGE_SHIFT); |
| 335 | } |
| 336 | |
| 337 | /** |
| 338 | * crypt_extent |
| 339 | * @crypt_stat: crypt_stat containing cryptographic context for the |
| 340 | * encryption operation |
| 341 | * @dst_page: The page to write the result into |
| 342 | * @src_page: The page to read from |
| 343 | * @extent_offset: Page extent offset for use in generating IV |
| 344 | * @op: ENCRYPT or DECRYPT to indicate the desired operation |
| 345 | * |
| 346 | * Encrypts or decrypts one extent of data. |
| 347 | * |
| 348 | * Return zero on success; non-zero otherwise |
| 349 | */ |
| 350 | static int crypt_extent(struct ecryptfs_crypt_stat *crypt_stat, |
| 351 | struct page *dst_page, |
| 352 | struct page *src_page, |
| 353 | unsigned long extent_offset, int op) |
| 354 | { |
| 355 | pgoff_t page_index = op == ENCRYPT ? src_page->index : dst_page->index; |
| 356 | loff_t extent_base; |
| 357 | char extent_iv[ECRYPTFS_MAX_IV_BYTES]; |
| 358 | struct scatterlist src_sg, dst_sg; |
| 359 | size_t extent_size = crypt_stat->extent_size; |
| 360 | int rc; |
| 361 | |
| 362 | extent_base = (((loff_t)page_index) * (PAGE_SIZE / extent_size)); |
| 363 | rc = ecryptfs_derive_iv(extent_iv, crypt_stat, |
| 364 | (extent_base + extent_offset)); |
| 365 | if (rc) { |
| 366 | ecryptfs_printk(KERN_ERR, "Error attempting to derive IV for " |
| 367 | "extent [0x%.16llx]; rc = [%d]\n", |
| 368 | (unsigned long long)(extent_base + extent_offset), rc); |
| 369 | goto out; |
| 370 | } |
| 371 | |
| 372 | sg_init_table(&src_sg, 1); |
| 373 | sg_init_table(&dst_sg, 1); |
| 374 | |
| 375 | sg_set_page(&src_sg, src_page, extent_size, |
| 376 | extent_offset * extent_size); |
| 377 | sg_set_page(&dst_sg, dst_page, extent_size, |
| 378 | extent_offset * extent_size); |
| 379 | |
| 380 | rc = crypt_scatterlist(crypt_stat, &dst_sg, &src_sg, extent_size, |
| 381 | extent_iv, op); |
| 382 | if (rc < 0) { |
| 383 | printk(KERN_ERR "%s: Error attempting to crypt page with " |
| 384 | "page_index = [%ld], extent_offset = [%ld]; " |
| 385 | "rc = [%d]\n", __func__, page_index, extent_offset, rc); |
| 386 | goto out; |
| 387 | } |
| 388 | rc = 0; |
| 389 | out: |
| 390 | return rc; |
| 391 | } |
| 392 | |
| 393 | /** |
| 394 | * ecryptfs_encrypt_page |
| 395 | * @page: Page mapped from the eCryptfs inode for the file; contains |
| 396 | * decrypted content that needs to be encrypted (to a temporary |
| 397 | * page; not in place) and written out to the lower file |
| 398 | * |
| 399 | * Encrypt an eCryptfs page. This is done on a per-extent basis. Note |
| 400 | * that eCryptfs pages may straddle the lower pages -- for instance, |
| 401 | * if the file was created on a machine with an 8K page size |
| 402 | * (resulting in an 8K header), and then the file is copied onto a |
| 403 | * host with a 32K page size, then when reading page 0 of the eCryptfs |
| 404 | * file, 24K of page 0 of the lower file will be read and decrypted, |
| 405 | * and then 8K of page 1 of the lower file will be read and decrypted. |
| 406 | * |
| 407 | * Returns zero on success; negative on error |
| 408 | */ |
| 409 | int ecryptfs_encrypt_page(struct page *page) |
| 410 | { |
| 411 | struct inode *ecryptfs_inode; |
| 412 | struct ecryptfs_crypt_stat *crypt_stat; |
| 413 | char *enc_extent_virt; |
| 414 | struct page *enc_extent_page = NULL; |
| 415 | loff_t extent_offset; |
| 416 | loff_t lower_offset; |
| 417 | int rc = 0; |
| 418 | |
| 419 | ecryptfs_inode = page->mapping->host; |
| 420 | crypt_stat = |
| 421 | &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat); |
| 422 | BUG_ON(!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)); |
| 423 | enc_extent_page = alloc_page(GFP_USER); |
| 424 | if (!enc_extent_page) { |
| 425 | rc = -ENOMEM; |
| 426 | ecryptfs_printk(KERN_ERR, "Error allocating memory for " |
| 427 | "encrypted extent\n"); |
| 428 | goto out; |
| 429 | } |
| 430 | |
| 431 | for (extent_offset = 0; |
| 432 | extent_offset < (PAGE_SIZE / crypt_stat->extent_size); |
| 433 | extent_offset++) { |
| 434 | rc = crypt_extent(crypt_stat, enc_extent_page, page, |
| 435 | extent_offset, ENCRYPT); |
| 436 | if (rc) { |
| 437 | printk(KERN_ERR "%s: Error encrypting extent; " |
| 438 | "rc = [%d]\n", __func__, rc); |
| 439 | goto out; |
| 440 | } |
| 441 | } |
| 442 | |
| 443 | lower_offset = lower_offset_for_page(crypt_stat, page); |
| 444 | enc_extent_virt = kmap_local_page(enc_extent_page); |
| 445 | rc = ecryptfs_write_lower(ecryptfs_inode, enc_extent_virt, lower_offset, |
| 446 | PAGE_SIZE); |
| 447 | kunmap_local(enc_extent_virt); |
| 448 | if (rc < 0) { |
| 449 | ecryptfs_printk(KERN_ERR, |
| 450 | "Error attempting to write lower page; rc = [%d]\n", |
| 451 | rc); |
| 452 | goto out; |
| 453 | } |
| 454 | rc = 0; |
| 455 | out: |
| 456 | if (enc_extent_page) { |
| 457 | __free_page(enc_extent_page); |
| 458 | } |
| 459 | return rc; |
| 460 | } |
| 461 | |
| 462 | /** |
| 463 | * ecryptfs_decrypt_page |
| 464 | * @page: Page mapped from the eCryptfs inode for the file; data read |
| 465 | * and decrypted from the lower file will be written into this |
| 466 | * page |
| 467 | * |
| 468 | * Decrypt an eCryptfs page. This is done on a per-extent basis. Note |
| 469 | * that eCryptfs pages may straddle the lower pages -- for instance, |
| 470 | * if the file was created on a machine with an 8K page size |
| 471 | * (resulting in an 8K header), and then the file is copied onto a |
| 472 | * host with a 32K page size, then when reading page 0 of the eCryptfs |
| 473 | * file, 24K of page 0 of the lower file will be read and decrypted, |
| 474 | * and then 8K of page 1 of the lower file will be read and decrypted. |
| 475 | * |
| 476 | * Returns zero on success; negative on error |
| 477 | */ |
| 478 | int ecryptfs_decrypt_page(struct page *page) |
| 479 | { |
| 480 | struct inode *ecryptfs_inode; |
| 481 | struct ecryptfs_crypt_stat *crypt_stat; |
| 482 | char *page_virt; |
| 483 | unsigned long extent_offset; |
| 484 | loff_t lower_offset; |
| 485 | int rc = 0; |
| 486 | |
| 487 | ecryptfs_inode = page->mapping->host; |
| 488 | crypt_stat = |
| 489 | &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat); |
| 490 | BUG_ON(!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)); |
| 491 | |
| 492 | lower_offset = lower_offset_for_page(crypt_stat, page); |
| 493 | page_virt = kmap_local_page(page); |
| 494 | rc = ecryptfs_read_lower(page_virt, lower_offset, PAGE_SIZE, |
| 495 | ecryptfs_inode); |
| 496 | kunmap_local(page_virt); |
| 497 | if (rc < 0) { |
| 498 | ecryptfs_printk(KERN_ERR, |
| 499 | "Error attempting to read lower page; rc = [%d]\n", |
| 500 | rc); |
| 501 | goto out; |
| 502 | } |
| 503 | |
| 504 | for (extent_offset = 0; |
| 505 | extent_offset < (PAGE_SIZE / crypt_stat->extent_size); |
| 506 | extent_offset++) { |
| 507 | rc = crypt_extent(crypt_stat, page, page, |
| 508 | extent_offset, DECRYPT); |
| 509 | if (rc) { |
| 510 | printk(KERN_ERR "%s: Error decrypting extent; " |
| 511 | "rc = [%d]\n", __func__, rc); |
| 512 | goto out; |
| 513 | } |
| 514 | } |
| 515 | out: |
| 516 | return rc; |
| 517 | } |
| 518 | |
| 519 | #define ECRYPTFS_MAX_SCATTERLIST_LEN 4 |
| 520 | |
| 521 | /** |
| 522 | * ecryptfs_init_crypt_ctx |
| 523 | * @crypt_stat: Uninitialized crypt stats structure |
| 524 | * |
| 525 | * Initialize the crypto context. |
| 526 | * |
| 527 | * TODO: Performance: Keep a cache of initialized cipher contexts; |
| 528 | * only init if needed |
| 529 | */ |
| 530 | int ecryptfs_init_crypt_ctx(struct ecryptfs_crypt_stat *crypt_stat) |
| 531 | { |
| 532 | char *full_alg_name; |
| 533 | int rc = -EINVAL; |
| 534 | |
| 535 | ecryptfs_printk(KERN_DEBUG, |
| 536 | "Initializing cipher [%s]; strlen = [%d]; " |
| 537 | "key_size_bits = [%zd]\n", |
| 538 | crypt_stat->cipher, (int)strlen(crypt_stat->cipher), |
| 539 | crypt_stat->key_size << 3); |
| 540 | mutex_lock(&crypt_stat->cs_tfm_mutex); |
| 541 | if (crypt_stat->tfm) { |
| 542 | rc = 0; |
| 543 | goto out_unlock; |
| 544 | } |
| 545 | rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name, |
| 546 | crypt_stat->cipher, "cbc"); |
| 547 | if (rc) |
| 548 | goto out_unlock; |
| 549 | crypt_stat->tfm = crypto_alloc_skcipher(full_alg_name, 0, 0); |
| 550 | if (IS_ERR(crypt_stat->tfm)) { |
| 551 | rc = PTR_ERR(crypt_stat->tfm); |
| 552 | crypt_stat->tfm = NULL; |
| 553 | ecryptfs_printk(KERN_ERR, "cryptfs: init_crypt_ctx(): " |
| 554 | "Error initializing cipher [%s]\n", |
| 555 | full_alg_name); |
| 556 | goto out_free; |
| 557 | } |
| 558 | crypto_skcipher_set_flags(crypt_stat->tfm, |
| 559 | CRYPTO_TFM_REQ_FORBID_WEAK_KEYS); |
| 560 | rc = 0; |
| 561 | out_free: |
| 562 | kfree(full_alg_name); |
| 563 | out_unlock: |
| 564 | mutex_unlock(&crypt_stat->cs_tfm_mutex); |
| 565 | return rc; |
| 566 | } |
| 567 | |
| 568 | static void set_extent_mask_and_shift(struct ecryptfs_crypt_stat *crypt_stat) |
| 569 | { |
| 570 | int extent_size_tmp; |
| 571 | |
| 572 | crypt_stat->extent_mask = 0xFFFFFFFF; |
| 573 | crypt_stat->extent_shift = 0; |
| 574 | if (crypt_stat->extent_size == 0) |
| 575 | return; |
| 576 | extent_size_tmp = crypt_stat->extent_size; |
| 577 | while ((extent_size_tmp & 0x01) == 0) { |
| 578 | extent_size_tmp >>= 1; |
| 579 | crypt_stat->extent_mask <<= 1; |
| 580 | crypt_stat->extent_shift++; |
| 581 | } |
| 582 | } |
| 583 | |
| 584 | void ecryptfs_set_default_sizes(struct ecryptfs_crypt_stat *crypt_stat) |
| 585 | { |
| 586 | /* Default values; may be overwritten as we are parsing the |
| 587 | * packets. */ |
| 588 | crypt_stat->extent_size = ECRYPTFS_DEFAULT_EXTENT_SIZE; |
| 589 | set_extent_mask_and_shift(crypt_stat); |
| 590 | crypt_stat->iv_bytes = ECRYPTFS_DEFAULT_IV_BYTES; |
| 591 | if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR) |
| 592 | crypt_stat->metadata_size = ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE; |
| 593 | else { |
| 594 | if (PAGE_SIZE <= ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE) |
| 595 | crypt_stat->metadata_size = |
| 596 | ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE; |
| 597 | else |
| 598 | crypt_stat->metadata_size = PAGE_SIZE; |
| 599 | } |
| 600 | } |
| 601 | |
| 602 | /* |
| 603 | * ecryptfs_compute_root_iv |
| 604 | * |
| 605 | * On error, sets the root IV to all 0's. |
| 606 | */ |
| 607 | int ecryptfs_compute_root_iv(struct ecryptfs_crypt_stat *crypt_stat) |
| 608 | { |
| 609 | int rc = 0; |
| 610 | char dst[MD5_DIGEST_SIZE]; |
| 611 | |
| 612 | BUG_ON(crypt_stat->iv_bytes > MD5_DIGEST_SIZE); |
| 613 | BUG_ON(crypt_stat->iv_bytes <= 0); |
| 614 | if (!(crypt_stat->flags & ECRYPTFS_KEY_VALID)) { |
| 615 | rc = -EINVAL; |
| 616 | ecryptfs_printk(KERN_WARNING, "Session key not valid; " |
| 617 | "cannot generate root IV\n"); |
| 618 | goto out; |
| 619 | } |
| 620 | rc = ecryptfs_calculate_md5(dst, crypt_stat, crypt_stat->key, |
| 621 | crypt_stat->key_size); |
| 622 | if (rc) { |
| 623 | ecryptfs_printk(KERN_WARNING, "Error attempting to compute " |
| 624 | "MD5 while generating root IV\n"); |
| 625 | goto out; |
| 626 | } |
| 627 | memcpy(crypt_stat->root_iv, dst, crypt_stat->iv_bytes); |
| 628 | out: |
| 629 | if (rc) { |
| 630 | memset(crypt_stat->root_iv, 0, crypt_stat->iv_bytes); |
| 631 | crypt_stat->flags |= ECRYPTFS_SECURITY_WARNING; |
| 632 | } |
| 633 | return rc; |
| 634 | } |
| 635 | |
| 636 | static void ecryptfs_generate_new_key(struct ecryptfs_crypt_stat *crypt_stat) |
| 637 | { |
| 638 | get_random_bytes(crypt_stat->key, crypt_stat->key_size); |
| 639 | crypt_stat->flags |= ECRYPTFS_KEY_VALID; |
| 640 | ecryptfs_compute_root_iv(crypt_stat); |
| 641 | if (unlikely(ecryptfs_verbosity > 0)) { |
| 642 | ecryptfs_printk(KERN_DEBUG, "Generated new session key:\n"); |
| 643 | ecryptfs_dump_hex(crypt_stat->key, |
| 644 | crypt_stat->key_size); |
| 645 | } |
| 646 | } |
| 647 | |
| 648 | /** |
| 649 | * ecryptfs_copy_mount_wide_flags_to_inode_flags |
| 650 | * @crypt_stat: The inode's cryptographic context |
| 651 | * @mount_crypt_stat: The mount point's cryptographic context |
| 652 | * |
| 653 | * This function propagates the mount-wide flags to individual inode |
| 654 | * flags. |
| 655 | */ |
| 656 | static void ecryptfs_copy_mount_wide_flags_to_inode_flags( |
| 657 | struct ecryptfs_crypt_stat *crypt_stat, |
| 658 | struct ecryptfs_mount_crypt_stat *mount_crypt_stat) |
| 659 | { |
| 660 | if (mount_crypt_stat->flags & ECRYPTFS_XATTR_METADATA_ENABLED) |
| 661 | crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR; |
| 662 | if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED) |
| 663 | crypt_stat->flags |= ECRYPTFS_VIEW_AS_ENCRYPTED; |
| 664 | if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) { |
| 665 | crypt_stat->flags |= ECRYPTFS_ENCRYPT_FILENAMES; |
| 666 | if (mount_crypt_stat->flags |
| 667 | & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK) |
| 668 | crypt_stat->flags |= ECRYPTFS_ENCFN_USE_MOUNT_FNEK; |
| 669 | else if (mount_crypt_stat->flags |
| 670 | & ECRYPTFS_GLOBAL_ENCFN_USE_FEK) |
| 671 | crypt_stat->flags |= ECRYPTFS_ENCFN_USE_FEK; |
| 672 | } |
| 673 | } |
| 674 | |
| 675 | static int ecryptfs_copy_mount_wide_sigs_to_inode_sigs( |
| 676 | struct ecryptfs_crypt_stat *crypt_stat, |
| 677 | struct ecryptfs_mount_crypt_stat *mount_crypt_stat) |
| 678 | { |
| 679 | struct ecryptfs_global_auth_tok *global_auth_tok; |
| 680 | int rc = 0; |
| 681 | |
| 682 | mutex_lock(&crypt_stat->keysig_list_mutex); |
| 683 | mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex); |
| 684 | |
| 685 | list_for_each_entry(global_auth_tok, |
| 686 | &mount_crypt_stat->global_auth_tok_list, |
| 687 | mount_crypt_stat_list) { |
| 688 | if (global_auth_tok->flags & ECRYPTFS_AUTH_TOK_FNEK) |
| 689 | continue; |
| 690 | rc = ecryptfs_add_keysig(crypt_stat, global_auth_tok->sig); |
| 691 | if (rc) { |
| 692 | printk(KERN_ERR "Error adding keysig; rc = [%d]\n", rc); |
| 693 | goto out; |
| 694 | } |
| 695 | } |
| 696 | |
| 697 | out: |
| 698 | mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex); |
| 699 | mutex_unlock(&crypt_stat->keysig_list_mutex); |
| 700 | return rc; |
| 701 | } |
| 702 | |
| 703 | /** |
| 704 | * ecryptfs_set_default_crypt_stat_vals |
| 705 | * @crypt_stat: The inode's cryptographic context |
| 706 | * @mount_crypt_stat: The mount point's cryptographic context |
| 707 | * |
| 708 | * Default values in the event that policy does not override them. |
| 709 | */ |
| 710 | static void ecryptfs_set_default_crypt_stat_vals( |
| 711 | struct ecryptfs_crypt_stat *crypt_stat, |
| 712 | struct ecryptfs_mount_crypt_stat *mount_crypt_stat) |
| 713 | { |
| 714 | ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat, |
| 715 | mount_crypt_stat); |
| 716 | ecryptfs_set_default_sizes(crypt_stat); |
| 717 | strcpy(crypt_stat->cipher, ECRYPTFS_DEFAULT_CIPHER); |
| 718 | crypt_stat->key_size = ECRYPTFS_DEFAULT_KEY_BYTES; |
| 719 | crypt_stat->flags &= ~(ECRYPTFS_KEY_VALID); |
| 720 | crypt_stat->file_version = ECRYPTFS_FILE_VERSION; |
| 721 | crypt_stat->mount_crypt_stat = mount_crypt_stat; |
| 722 | } |
| 723 | |
| 724 | /** |
| 725 | * ecryptfs_new_file_context |
| 726 | * @ecryptfs_inode: The eCryptfs inode |
| 727 | * |
| 728 | * If the crypto context for the file has not yet been established, |
| 729 | * this is where we do that. Establishing a new crypto context |
| 730 | * involves the following decisions: |
| 731 | * - What cipher to use? |
| 732 | * - What set of authentication tokens to use? |
| 733 | * Here we just worry about getting enough information into the |
| 734 | * authentication tokens so that we know that they are available. |
| 735 | * We associate the available authentication tokens with the new file |
| 736 | * via the set of signatures in the crypt_stat struct. Later, when |
| 737 | * the headers are actually written out, we may again defer to |
| 738 | * userspace to perform the encryption of the session key; for the |
| 739 | * foreseeable future, this will be the case with public key packets. |
| 740 | * |
| 741 | * Returns zero on success; non-zero otherwise |
| 742 | */ |
| 743 | int ecryptfs_new_file_context(struct inode *ecryptfs_inode) |
| 744 | { |
| 745 | struct ecryptfs_crypt_stat *crypt_stat = |
| 746 | &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat; |
| 747 | struct ecryptfs_mount_crypt_stat *mount_crypt_stat = |
| 748 | &ecryptfs_superblock_to_private( |
| 749 | ecryptfs_inode->i_sb)->mount_crypt_stat; |
| 750 | int cipher_name_len; |
| 751 | int rc = 0; |
| 752 | |
| 753 | ecryptfs_set_default_crypt_stat_vals(crypt_stat, mount_crypt_stat); |
| 754 | crypt_stat->flags |= (ECRYPTFS_ENCRYPTED | ECRYPTFS_KEY_VALID); |
| 755 | ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat, |
| 756 | mount_crypt_stat); |
| 757 | rc = ecryptfs_copy_mount_wide_sigs_to_inode_sigs(crypt_stat, |
| 758 | mount_crypt_stat); |
| 759 | if (rc) { |
| 760 | printk(KERN_ERR "Error attempting to copy mount-wide key sigs " |
| 761 | "to the inode key sigs; rc = [%d]\n", rc); |
| 762 | goto out; |
| 763 | } |
| 764 | cipher_name_len = |
| 765 | strlen(mount_crypt_stat->global_default_cipher_name); |
| 766 | memcpy(crypt_stat->cipher, |
| 767 | mount_crypt_stat->global_default_cipher_name, |
| 768 | cipher_name_len); |
| 769 | crypt_stat->cipher[cipher_name_len] = '\0'; |
| 770 | crypt_stat->key_size = |
| 771 | mount_crypt_stat->global_default_cipher_key_size; |
| 772 | ecryptfs_generate_new_key(crypt_stat); |
| 773 | rc = ecryptfs_init_crypt_ctx(crypt_stat); |
| 774 | if (rc) |
| 775 | ecryptfs_printk(KERN_ERR, "Error initializing cryptographic " |
| 776 | "context for cipher [%s]: rc = [%d]\n", |
| 777 | crypt_stat->cipher, rc); |
| 778 | out: |
| 779 | return rc; |
| 780 | } |
| 781 | |
| 782 | /** |
| 783 | * ecryptfs_validate_marker - check for the ecryptfs marker |
| 784 | * @data: The data block in which to check |
| 785 | * |
| 786 | * Returns zero if marker found; -EINVAL if not found |
| 787 | */ |
| 788 | static int ecryptfs_validate_marker(char *data) |
| 789 | { |
| 790 | u32 m_1, m_2; |
| 791 | |
| 792 | m_1 = get_unaligned_be32(data); |
| 793 | m_2 = get_unaligned_be32(data + 4); |
| 794 | if ((m_1 ^ MAGIC_ECRYPTFS_MARKER) == m_2) |
| 795 | return 0; |
| 796 | ecryptfs_printk(KERN_DEBUG, "m_1 = [0x%.8x]; m_2 = [0x%.8x]; " |
| 797 | "MAGIC_ECRYPTFS_MARKER = [0x%.8x]\n", m_1, m_2, |
| 798 | MAGIC_ECRYPTFS_MARKER); |
| 799 | ecryptfs_printk(KERN_DEBUG, "(m_1 ^ MAGIC_ECRYPTFS_MARKER) = " |
| 800 | "[0x%.8x]\n", (m_1 ^ MAGIC_ECRYPTFS_MARKER)); |
| 801 | return -EINVAL; |
| 802 | } |
| 803 | |
| 804 | struct ecryptfs_flag_map_elem { |
| 805 | u32 file_flag; |
| 806 | u32 local_flag; |
| 807 | }; |
| 808 | |
| 809 | /* Add support for additional flags by adding elements here. */ |
| 810 | static struct ecryptfs_flag_map_elem ecryptfs_flag_map[] = { |
| 811 | {0x00000001, ECRYPTFS_ENABLE_HMAC}, |
| 812 | {0x00000002, ECRYPTFS_ENCRYPTED}, |
| 813 | {0x00000004, ECRYPTFS_METADATA_IN_XATTR}, |
| 814 | {0x00000008, ECRYPTFS_ENCRYPT_FILENAMES} |
| 815 | }; |
| 816 | |
| 817 | /** |
| 818 | * ecryptfs_process_flags |
| 819 | * @crypt_stat: The cryptographic context |
| 820 | * @page_virt: Source data to be parsed |
| 821 | * @bytes_read: Updated with the number of bytes read |
| 822 | */ |
| 823 | static void ecryptfs_process_flags(struct ecryptfs_crypt_stat *crypt_stat, |
| 824 | char *page_virt, int *bytes_read) |
| 825 | { |
| 826 | int i; |
| 827 | u32 flags; |
| 828 | |
| 829 | flags = get_unaligned_be32(page_virt); |
| 830 | for (i = 0; i < ARRAY_SIZE(ecryptfs_flag_map); i++) |
| 831 | if (flags & ecryptfs_flag_map[i].file_flag) { |
| 832 | crypt_stat->flags |= ecryptfs_flag_map[i].local_flag; |
| 833 | } else |
| 834 | crypt_stat->flags &= ~(ecryptfs_flag_map[i].local_flag); |
| 835 | /* Version is in top 8 bits of the 32-bit flag vector */ |
| 836 | crypt_stat->file_version = ((flags >> 24) & 0xFF); |
| 837 | (*bytes_read) = 4; |
| 838 | } |
| 839 | |
| 840 | /** |
| 841 | * write_ecryptfs_marker |
| 842 | * @page_virt: The pointer to in a page to begin writing the marker |
| 843 | * @written: Number of bytes written |
| 844 | * |
| 845 | * Marker = 0x3c81b7f5 |
| 846 | */ |
| 847 | static void write_ecryptfs_marker(char *page_virt, size_t *written) |
| 848 | { |
| 849 | u32 m_1, m_2; |
| 850 | |
| 851 | get_random_bytes(&m_1, (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2)); |
| 852 | m_2 = (m_1 ^ MAGIC_ECRYPTFS_MARKER); |
| 853 | put_unaligned_be32(m_1, page_virt); |
| 854 | page_virt += (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2); |
| 855 | put_unaligned_be32(m_2, page_virt); |
| 856 | (*written) = MAGIC_ECRYPTFS_MARKER_SIZE_BYTES; |
| 857 | } |
| 858 | |
| 859 | void ecryptfs_write_crypt_stat_flags(char *page_virt, |
| 860 | struct ecryptfs_crypt_stat *crypt_stat, |
| 861 | size_t *written) |
| 862 | { |
| 863 | u32 flags = 0; |
| 864 | int i; |
| 865 | |
| 866 | for (i = 0; i < ARRAY_SIZE(ecryptfs_flag_map); i++) |
| 867 | if (crypt_stat->flags & ecryptfs_flag_map[i].local_flag) |
| 868 | flags |= ecryptfs_flag_map[i].file_flag; |
| 869 | /* Version is in top 8 bits of the 32-bit flag vector */ |
| 870 | flags |= ((((u8)crypt_stat->file_version) << 24) & 0xFF000000); |
| 871 | put_unaligned_be32(flags, page_virt); |
| 872 | (*written) = 4; |
| 873 | } |
| 874 | |
| 875 | struct ecryptfs_cipher_code_str_map_elem { |
| 876 | char cipher_str[16]; |
| 877 | u8 cipher_code; |
| 878 | }; |
| 879 | |
| 880 | /* Add support for additional ciphers by adding elements here. The |
| 881 | * cipher_code is whatever OpenPGP applications use to identify the |
| 882 | * ciphers. List in order of probability. */ |
| 883 | static struct ecryptfs_cipher_code_str_map_elem |
| 884 | ecryptfs_cipher_code_str_map[] = { |
| 885 | {"aes",RFC2440_CIPHER_AES_128 }, |
| 886 | {"blowfish", RFC2440_CIPHER_BLOWFISH}, |
| 887 | {"des3_ede", RFC2440_CIPHER_DES3_EDE}, |
| 888 | {"cast5", RFC2440_CIPHER_CAST_5}, |
| 889 | {"twofish", RFC2440_CIPHER_TWOFISH}, |
| 890 | {"cast6", RFC2440_CIPHER_CAST_6}, |
| 891 | {"aes", RFC2440_CIPHER_AES_192}, |
| 892 | {"aes", RFC2440_CIPHER_AES_256} |
| 893 | }; |
| 894 | |
| 895 | /** |
| 896 | * ecryptfs_code_for_cipher_string |
| 897 | * @cipher_name: The string alias for the cipher |
| 898 | * @key_bytes: Length of key in bytes; used for AES code selection |
| 899 | * |
| 900 | * Returns zero on no match, or the cipher code on match |
| 901 | */ |
| 902 | u8 ecryptfs_code_for_cipher_string(char *cipher_name, size_t key_bytes) |
| 903 | { |
| 904 | int i; |
| 905 | u8 code = 0; |
| 906 | struct ecryptfs_cipher_code_str_map_elem *map = |
| 907 | ecryptfs_cipher_code_str_map; |
| 908 | |
| 909 | if (strcmp(cipher_name, "aes") == 0) { |
| 910 | switch (key_bytes) { |
| 911 | case 16: |
| 912 | code = RFC2440_CIPHER_AES_128; |
| 913 | break; |
| 914 | case 24: |
| 915 | code = RFC2440_CIPHER_AES_192; |
| 916 | break; |
| 917 | case 32: |
| 918 | code = RFC2440_CIPHER_AES_256; |
| 919 | } |
| 920 | } else { |
| 921 | for (i = 0; i < ARRAY_SIZE(ecryptfs_cipher_code_str_map); i++) |
| 922 | if (strcmp(cipher_name, map[i].cipher_str) == 0) { |
| 923 | code = map[i].cipher_code; |
| 924 | break; |
| 925 | } |
| 926 | } |
| 927 | return code; |
| 928 | } |
| 929 | |
| 930 | /** |
| 931 | * ecryptfs_cipher_code_to_string |
| 932 | * @str: Destination to write out the cipher name |
| 933 | * @cipher_code: The code to convert to cipher name string |
| 934 | * |
| 935 | * Returns zero on success |
| 936 | */ |
| 937 | int ecryptfs_cipher_code_to_string(char *str, u8 cipher_code) |
| 938 | { |
| 939 | int rc = 0; |
| 940 | int i; |
| 941 | |
| 942 | str[0] = '\0'; |
| 943 | for (i = 0; i < ARRAY_SIZE(ecryptfs_cipher_code_str_map); i++) |
| 944 | if (cipher_code == ecryptfs_cipher_code_str_map[i].cipher_code) |
| 945 | strcpy(str, ecryptfs_cipher_code_str_map[i].cipher_str); |
| 946 | if (str[0] == '\0') { |
| 947 | ecryptfs_printk(KERN_WARNING, "Cipher code not recognized: " |
| 948 | "[%d]\n", cipher_code); |
| 949 | rc = -EINVAL; |
| 950 | } |
| 951 | return rc; |
| 952 | } |
| 953 | |
| 954 | int ecryptfs_read_and_validate_header_region(struct inode *inode) |
| 955 | { |
| 956 | u8 file_size[ECRYPTFS_SIZE_AND_MARKER_BYTES]; |
| 957 | u8 *marker = file_size + ECRYPTFS_FILE_SIZE_BYTES; |
| 958 | int rc; |
| 959 | |
| 960 | rc = ecryptfs_read_lower(file_size, 0, ECRYPTFS_SIZE_AND_MARKER_BYTES, |
| 961 | inode); |
| 962 | if (rc < 0) |
| 963 | return rc; |
| 964 | else if (rc < ECRYPTFS_SIZE_AND_MARKER_BYTES) |
| 965 | return -EINVAL; |
| 966 | rc = ecryptfs_validate_marker(marker); |
| 967 | if (!rc) |
| 968 | ecryptfs_i_size_init(file_size, inode); |
| 969 | return rc; |
| 970 | } |
| 971 | |
| 972 | void |
| 973 | ecryptfs_write_header_metadata(char *virt, |
| 974 | struct ecryptfs_crypt_stat *crypt_stat, |
| 975 | size_t *written) |
| 976 | { |
| 977 | u32 header_extent_size; |
| 978 | u16 num_header_extents_at_front; |
| 979 | |
| 980 | header_extent_size = (u32)crypt_stat->extent_size; |
| 981 | num_header_extents_at_front = |
| 982 | (u16)(crypt_stat->metadata_size / crypt_stat->extent_size); |
| 983 | put_unaligned_be32(header_extent_size, virt); |
| 984 | virt += 4; |
| 985 | put_unaligned_be16(num_header_extents_at_front, virt); |
| 986 | (*written) = 6; |
| 987 | } |
| 988 | |
| 989 | struct kmem_cache *ecryptfs_header_cache; |
| 990 | |
| 991 | /** |
| 992 | * ecryptfs_write_headers_virt |
| 993 | * @page_virt: The virtual address to write the headers to |
| 994 | * @max: The size of memory allocated at page_virt |
| 995 | * @size: Set to the number of bytes written by this function |
| 996 | * @crypt_stat: The cryptographic context |
| 997 | * @ecryptfs_dentry: The eCryptfs dentry |
| 998 | * |
| 999 | * Format version: 1 |
| 1000 | * |
| 1001 | * Header Extent: |
| 1002 | * Octets 0-7: Unencrypted file size (big-endian) |
| 1003 | * Octets 8-15: eCryptfs special marker |
| 1004 | * Octets 16-19: Flags |
| 1005 | * Octet 16: File format version number (between 0 and 255) |
| 1006 | * Octets 17-18: Reserved |
| 1007 | * Octet 19: Bit 1 (lsb): Reserved |
| 1008 | * Bit 2: Encrypted? |
| 1009 | * Bits 3-8: Reserved |
| 1010 | * Octets 20-23: Header extent size (big-endian) |
| 1011 | * Octets 24-25: Number of header extents at front of file |
| 1012 | * (big-endian) |
| 1013 | * Octet 26: Begin RFC 2440 authentication token packet set |
| 1014 | * Data Extent 0: |
| 1015 | * Lower data (CBC encrypted) |
| 1016 | * Data Extent 1: |
| 1017 | * Lower data (CBC encrypted) |
| 1018 | * ... |
| 1019 | * |
| 1020 | * Returns zero on success |
| 1021 | */ |
| 1022 | static int ecryptfs_write_headers_virt(char *page_virt, size_t max, |
| 1023 | size_t *size, |
| 1024 | struct ecryptfs_crypt_stat *crypt_stat, |
| 1025 | struct dentry *ecryptfs_dentry) |
| 1026 | { |
| 1027 | int rc; |
| 1028 | size_t written; |
| 1029 | size_t offset; |
| 1030 | |
| 1031 | offset = ECRYPTFS_FILE_SIZE_BYTES; |
| 1032 | write_ecryptfs_marker((page_virt + offset), &written); |
| 1033 | offset += written; |
| 1034 | ecryptfs_write_crypt_stat_flags((page_virt + offset), crypt_stat, |
| 1035 | &written); |
| 1036 | offset += written; |
| 1037 | ecryptfs_write_header_metadata((page_virt + offset), crypt_stat, |
| 1038 | &written); |
| 1039 | offset += written; |
| 1040 | rc = ecryptfs_generate_key_packet_set((page_virt + offset), crypt_stat, |
| 1041 | ecryptfs_dentry, &written, |
| 1042 | max - offset); |
| 1043 | if (rc) |
| 1044 | ecryptfs_printk(KERN_WARNING, "Error generating key packet " |
| 1045 | "set; rc = [%d]\n", rc); |
| 1046 | if (size) { |
| 1047 | offset += written; |
| 1048 | *size = offset; |
| 1049 | } |
| 1050 | return rc; |
| 1051 | } |
| 1052 | |
| 1053 | static int |
| 1054 | ecryptfs_write_metadata_to_contents(struct inode *ecryptfs_inode, |
| 1055 | char *virt, size_t virt_len) |
| 1056 | { |
| 1057 | int rc; |
| 1058 | |
| 1059 | rc = ecryptfs_write_lower(ecryptfs_inode, virt, |
| 1060 | 0, virt_len); |
| 1061 | if (rc < 0) |
| 1062 | printk(KERN_ERR "%s: Error attempting to write header " |
| 1063 | "information to lower file; rc = [%d]\n", __func__, rc); |
| 1064 | else |
| 1065 | rc = 0; |
| 1066 | return rc; |
| 1067 | } |
| 1068 | |
| 1069 | static int |
| 1070 | ecryptfs_write_metadata_to_xattr(struct dentry *ecryptfs_dentry, |
| 1071 | struct inode *ecryptfs_inode, |
| 1072 | char *page_virt, size_t size) |
| 1073 | { |
| 1074 | int rc; |
| 1075 | struct dentry *lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry); |
| 1076 | struct inode *lower_inode = d_inode(lower_dentry); |
| 1077 | |
| 1078 | if (!(lower_inode->i_opflags & IOP_XATTR)) { |
| 1079 | rc = -EOPNOTSUPP; |
| 1080 | goto out; |
| 1081 | } |
| 1082 | |
| 1083 | inode_lock(lower_inode); |
| 1084 | rc = __vfs_setxattr(&nop_mnt_idmap, lower_dentry, lower_inode, |
| 1085 | ECRYPTFS_XATTR_NAME, page_virt, size, 0); |
| 1086 | if (!rc && ecryptfs_inode) |
| 1087 | fsstack_copy_attr_all(ecryptfs_inode, lower_inode); |
| 1088 | inode_unlock(lower_inode); |
| 1089 | out: |
| 1090 | return rc; |
| 1091 | } |
| 1092 | |
| 1093 | static unsigned long ecryptfs_get_zeroed_pages(gfp_t gfp_mask, |
| 1094 | unsigned int order) |
| 1095 | { |
| 1096 | struct page *page; |
| 1097 | |
| 1098 | page = alloc_pages(gfp_mask | __GFP_ZERO, order); |
| 1099 | if (page) |
| 1100 | return (unsigned long) page_address(page); |
| 1101 | return 0; |
| 1102 | } |
| 1103 | |
| 1104 | /** |
| 1105 | * ecryptfs_write_metadata |
| 1106 | * @ecryptfs_dentry: The eCryptfs dentry, which should be negative |
| 1107 | * @ecryptfs_inode: The newly created eCryptfs inode |
| 1108 | * |
| 1109 | * Write the file headers out. This will likely involve a userspace |
| 1110 | * callout, in which the session key is encrypted with one or more |
| 1111 | * public keys and/or the passphrase necessary to do the encryption is |
| 1112 | * retrieved via a prompt. Exactly what happens at this point should |
| 1113 | * be policy-dependent. |
| 1114 | * |
| 1115 | * Returns zero on success; non-zero on error |
| 1116 | */ |
| 1117 | int ecryptfs_write_metadata(struct dentry *ecryptfs_dentry, |
| 1118 | struct inode *ecryptfs_inode) |
| 1119 | { |
| 1120 | struct ecryptfs_crypt_stat *crypt_stat = |
| 1121 | &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat; |
| 1122 | unsigned int order; |
| 1123 | char *virt; |
| 1124 | size_t virt_len; |
| 1125 | size_t size = 0; |
| 1126 | int rc = 0; |
| 1127 | |
| 1128 | if (likely(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) { |
| 1129 | if (!(crypt_stat->flags & ECRYPTFS_KEY_VALID)) { |
| 1130 | printk(KERN_ERR "Key is invalid; bailing out\n"); |
| 1131 | rc = -EINVAL; |
| 1132 | goto out; |
| 1133 | } |
| 1134 | } else { |
| 1135 | printk(KERN_WARNING "%s: Encrypted flag not set\n", |
| 1136 | __func__); |
| 1137 | rc = -EINVAL; |
| 1138 | goto out; |
| 1139 | } |
| 1140 | virt_len = crypt_stat->metadata_size; |
| 1141 | order = get_order(virt_len); |
| 1142 | /* Released in this function */ |
| 1143 | virt = (char *)ecryptfs_get_zeroed_pages(GFP_KERNEL, order); |
| 1144 | if (!virt) { |
| 1145 | printk(KERN_ERR "%s: Out of memory\n", __func__); |
| 1146 | rc = -ENOMEM; |
| 1147 | goto out; |
| 1148 | } |
| 1149 | /* Zeroed page ensures the in-header unencrypted i_size is set to 0 */ |
| 1150 | rc = ecryptfs_write_headers_virt(virt, virt_len, &size, crypt_stat, |
| 1151 | ecryptfs_dentry); |
| 1152 | if (unlikely(rc)) { |
| 1153 | printk(KERN_ERR "%s: Error whilst writing headers; rc = [%d]\n", |
| 1154 | __func__, rc); |
| 1155 | goto out_free; |
| 1156 | } |
| 1157 | if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR) |
| 1158 | rc = ecryptfs_write_metadata_to_xattr(ecryptfs_dentry, ecryptfs_inode, |
| 1159 | virt, size); |
| 1160 | else |
| 1161 | rc = ecryptfs_write_metadata_to_contents(ecryptfs_inode, virt, |
| 1162 | virt_len); |
| 1163 | if (rc) { |
| 1164 | printk(KERN_ERR "%s: Error writing metadata out to lower file; " |
| 1165 | "rc = [%d]\n", __func__, rc); |
| 1166 | goto out_free; |
| 1167 | } |
| 1168 | out_free: |
| 1169 | free_pages((unsigned long)virt, order); |
| 1170 | out: |
| 1171 | return rc; |
| 1172 | } |
| 1173 | |
| 1174 | #define ECRYPTFS_DONT_VALIDATE_HEADER_SIZE 0 |
| 1175 | #define ECRYPTFS_VALIDATE_HEADER_SIZE 1 |
| 1176 | static int parse_header_metadata(struct ecryptfs_crypt_stat *crypt_stat, |
| 1177 | char *virt, int *bytes_read, |
| 1178 | int validate_header_size) |
| 1179 | { |
| 1180 | int rc = 0; |
| 1181 | u32 header_extent_size; |
| 1182 | u16 num_header_extents_at_front; |
| 1183 | |
| 1184 | header_extent_size = get_unaligned_be32(virt); |
| 1185 | virt += sizeof(__be32); |
| 1186 | num_header_extents_at_front = get_unaligned_be16(virt); |
| 1187 | crypt_stat->metadata_size = (((size_t)num_header_extents_at_front |
| 1188 | * (size_t)header_extent_size)); |
| 1189 | (*bytes_read) = (sizeof(__be32) + sizeof(__be16)); |
| 1190 | if ((validate_header_size == ECRYPTFS_VALIDATE_HEADER_SIZE) |
| 1191 | && (crypt_stat->metadata_size |
| 1192 | < ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE)) { |
| 1193 | rc = -EINVAL; |
| 1194 | printk(KERN_WARNING "Invalid header size: [%zd]\n", |
| 1195 | crypt_stat->metadata_size); |
| 1196 | } |
| 1197 | return rc; |
| 1198 | } |
| 1199 | |
| 1200 | /** |
| 1201 | * set_default_header_data |
| 1202 | * @crypt_stat: The cryptographic context |
| 1203 | * |
| 1204 | * For version 0 file format; this function is only for backwards |
| 1205 | * compatibility for files created with the prior versions of |
| 1206 | * eCryptfs. |
| 1207 | */ |
| 1208 | static void set_default_header_data(struct ecryptfs_crypt_stat *crypt_stat) |
| 1209 | { |
| 1210 | crypt_stat->metadata_size = ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE; |
| 1211 | } |
| 1212 | |
| 1213 | void ecryptfs_i_size_init(const char *page_virt, struct inode *inode) |
| 1214 | { |
| 1215 | struct ecryptfs_mount_crypt_stat *mount_crypt_stat; |
| 1216 | struct ecryptfs_crypt_stat *crypt_stat; |
| 1217 | u64 file_size; |
| 1218 | |
| 1219 | crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat; |
| 1220 | mount_crypt_stat = |
| 1221 | &ecryptfs_superblock_to_private(inode->i_sb)->mount_crypt_stat; |
| 1222 | if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED) { |
| 1223 | file_size = i_size_read(ecryptfs_inode_to_lower(inode)); |
| 1224 | if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR) |
| 1225 | file_size += crypt_stat->metadata_size; |
| 1226 | } else |
| 1227 | file_size = get_unaligned_be64(page_virt); |
| 1228 | i_size_write(inode, (loff_t)file_size); |
| 1229 | crypt_stat->flags |= ECRYPTFS_I_SIZE_INITIALIZED; |
| 1230 | } |
| 1231 | |
| 1232 | /** |
| 1233 | * ecryptfs_read_headers_virt |
| 1234 | * @page_virt: The virtual address into which to read the headers |
| 1235 | * @crypt_stat: The cryptographic context |
| 1236 | * @ecryptfs_dentry: The eCryptfs dentry |
| 1237 | * @validate_header_size: Whether to validate the header size while reading |
| 1238 | * |
| 1239 | * Read/parse the header data. The header format is detailed in the |
| 1240 | * comment block for the ecryptfs_write_headers_virt() function. |
| 1241 | * |
| 1242 | * Returns zero on success |
| 1243 | */ |
| 1244 | static int ecryptfs_read_headers_virt(char *page_virt, |
| 1245 | struct ecryptfs_crypt_stat *crypt_stat, |
| 1246 | struct dentry *ecryptfs_dentry, |
| 1247 | int validate_header_size) |
| 1248 | { |
| 1249 | int rc = 0; |
| 1250 | int offset; |
| 1251 | int bytes_read; |
| 1252 | |
| 1253 | ecryptfs_set_default_sizes(crypt_stat); |
| 1254 | crypt_stat->mount_crypt_stat = &ecryptfs_superblock_to_private( |
| 1255 | ecryptfs_dentry->d_sb)->mount_crypt_stat; |
| 1256 | offset = ECRYPTFS_FILE_SIZE_BYTES; |
| 1257 | rc = ecryptfs_validate_marker(page_virt + offset); |
| 1258 | if (rc) |
| 1259 | goto out; |
| 1260 | if (!(crypt_stat->flags & ECRYPTFS_I_SIZE_INITIALIZED)) |
| 1261 | ecryptfs_i_size_init(page_virt, d_inode(ecryptfs_dentry)); |
| 1262 | offset += MAGIC_ECRYPTFS_MARKER_SIZE_BYTES; |
| 1263 | ecryptfs_process_flags(crypt_stat, (page_virt + offset), &bytes_read); |
| 1264 | if (crypt_stat->file_version > ECRYPTFS_SUPPORTED_FILE_VERSION) { |
| 1265 | ecryptfs_printk(KERN_WARNING, "File version is [%d]; only " |
| 1266 | "file version [%d] is supported by this " |
| 1267 | "version of eCryptfs\n", |
| 1268 | crypt_stat->file_version, |
| 1269 | ECRYPTFS_SUPPORTED_FILE_VERSION); |
| 1270 | rc = -EINVAL; |
| 1271 | goto out; |
| 1272 | } |
| 1273 | offset += bytes_read; |
| 1274 | if (crypt_stat->file_version >= 1) { |
| 1275 | rc = parse_header_metadata(crypt_stat, (page_virt + offset), |
| 1276 | &bytes_read, validate_header_size); |
| 1277 | if (rc) { |
| 1278 | ecryptfs_printk(KERN_WARNING, "Error reading header " |
| 1279 | "metadata; rc = [%d]\n", rc); |
| 1280 | } |
| 1281 | offset += bytes_read; |
| 1282 | } else |
| 1283 | set_default_header_data(crypt_stat); |
| 1284 | rc = ecryptfs_parse_packet_set(crypt_stat, (page_virt + offset), |
| 1285 | ecryptfs_dentry); |
| 1286 | out: |
| 1287 | return rc; |
| 1288 | } |
| 1289 | |
| 1290 | /** |
| 1291 | * ecryptfs_read_xattr_region |
| 1292 | * @page_virt: The vitual address into which to read the xattr data |
| 1293 | * @ecryptfs_inode: The eCryptfs inode |
| 1294 | * |
| 1295 | * Attempts to read the crypto metadata from the extended attribute |
| 1296 | * region of the lower file. |
| 1297 | * |
| 1298 | * Returns zero on success; non-zero on error |
| 1299 | */ |
| 1300 | int ecryptfs_read_xattr_region(char *page_virt, struct inode *ecryptfs_inode) |
| 1301 | { |
| 1302 | struct dentry *lower_dentry = |
| 1303 | ecryptfs_inode_to_private(ecryptfs_inode)->lower_file->f_path.dentry; |
| 1304 | ssize_t size; |
| 1305 | int rc = 0; |
| 1306 | |
| 1307 | size = ecryptfs_getxattr_lower(lower_dentry, |
| 1308 | ecryptfs_inode_to_lower(ecryptfs_inode), |
| 1309 | ECRYPTFS_XATTR_NAME, |
| 1310 | page_virt, ECRYPTFS_DEFAULT_EXTENT_SIZE); |
| 1311 | if (size < 0) { |
| 1312 | if (unlikely(ecryptfs_verbosity > 0)) |
| 1313 | printk(KERN_INFO "Error attempting to read the [%s] " |
| 1314 | "xattr from the lower file; return value = " |
| 1315 | "[%zd]\n", ECRYPTFS_XATTR_NAME, size); |
| 1316 | rc = -EINVAL; |
| 1317 | goto out; |
| 1318 | } |
| 1319 | out: |
| 1320 | return rc; |
| 1321 | } |
| 1322 | |
| 1323 | int ecryptfs_read_and_validate_xattr_region(struct dentry *dentry, |
| 1324 | struct inode *inode) |
| 1325 | { |
| 1326 | u8 file_size[ECRYPTFS_SIZE_AND_MARKER_BYTES]; |
| 1327 | u8 *marker = file_size + ECRYPTFS_FILE_SIZE_BYTES; |
| 1328 | int rc; |
| 1329 | |
| 1330 | rc = ecryptfs_getxattr_lower(ecryptfs_dentry_to_lower(dentry), |
| 1331 | ecryptfs_inode_to_lower(inode), |
| 1332 | ECRYPTFS_XATTR_NAME, file_size, |
| 1333 | ECRYPTFS_SIZE_AND_MARKER_BYTES); |
| 1334 | if (rc < 0) |
| 1335 | return rc; |
| 1336 | else if (rc < ECRYPTFS_SIZE_AND_MARKER_BYTES) |
| 1337 | return -EINVAL; |
| 1338 | rc = ecryptfs_validate_marker(marker); |
| 1339 | if (!rc) |
| 1340 | ecryptfs_i_size_init(file_size, inode); |
| 1341 | return rc; |
| 1342 | } |
| 1343 | |
| 1344 | /* |
| 1345 | * ecryptfs_read_metadata |
| 1346 | * |
| 1347 | * Common entry point for reading file metadata. From here, we could |
| 1348 | * retrieve the header information from the header region of the file, |
| 1349 | * the xattr region of the file, or some other repository that is |
| 1350 | * stored separately from the file itself. The current implementation |
| 1351 | * supports retrieving the metadata information from the file contents |
| 1352 | * and from the xattr region. |
| 1353 | * |
| 1354 | * Returns zero if valid headers found and parsed; non-zero otherwise |
| 1355 | */ |
| 1356 | int ecryptfs_read_metadata(struct dentry *ecryptfs_dentry) |
| 1357 | { |
| 1358 | int rc; |
| 1359 | char *page_virt; |
| 1360 | struct inode *ecryptfs_inode = d_inode(ecryptfs_dentry); |
| 1361 | struct ecryptfs_crypt_stat *crypt_stat = |
| 1362 | &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat; |
| 1363 | struct ecryptfs_mount_crypt_stat *mount_crypt_stat = |
| 1364 | &ecryptfs_superblock_to_private( |
| 1365 | ecryptfs_dentry->d_sb)->mount_crypt_stat; |
| 1366 | |
| 1367 | ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat, |
| 1368 | mount_crypt_stat); |
| 1369 | /* Read the first page from the underlying file */ |
| 1370 | page_virt = kmem_cache_alloc(ecryptfs_header_cache, GFP_USER); |
| 1371 | if (!page_virt) { |
| 1372 | rc = -ENOMEM; |
| 1373 | goto out; |
| 1374 | } |
| 1375 | rc = ecryptfs_read_lower(page_virt, 0, crypt_stat->extent_size, |
| 1376 | ecryptfs_inode); |
| 1377 | if (rc >= 0) |
| 1378 | rc = ecryptfs_read_headers_virt(page_virt, crypt_stat, |
| 1379 | ecryptfs_dentry, |
| 1380 | ECRYPTFS_VALIDATE_HEADER_SIZE); |
| 1381 | if (rc) { |
| 1382 | /* metadata is not in the file header, so try xattrs */ |
| 1383 | memset(page_virt, 0, PAGE_SIZE); |
| 1384 | rc = ecryptfs_read_xattr_region(page_virt, ecryptfs_inode); |
| 1385 | if (rc) { |
| 1386 | printk(KERN_DEBUG "Valid eCryptfs headers not found in " |
| 1387 | "file header region or xattr region, inode %lu\n", |
| 1388 | ecryptfs_inode->i_ino); |
| 1389 | rc = -EINVAL; |
| 1390 | goto out; |
| 1391 | } |
| 1392 | rc = ecryptfs_read_headers_virt(page_virt, crypt_stat, |
| 1393 | ecryptfs_dentry, |
| 1394 | ECRYPTFS_DONT_VALIDATE_HEADER_SIZE); |
| 1395 | if (rc) { |
| 1396 | printk(KERN_DEBUG "Valid eCryptfs headers not found in " |
| 1397 | "file xattr region either, inode %lu\n", |
| 1398 | ecryptfs_inode->i_ino); |
| 1399 | rc = -EINVAL; |
| 1400 | } |
| 1401 | if (crypt_stat->mount_crypt_stat->flags |
| 1402 | & ECRYPTFS_XATTR_METADATA_ENABLED) { |
| 1403 | crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR; |
| 1404 | } else { |
| 1405 | printk(KERN_WARNING "Attempt to access file with " |
| 1406 | "crypto metadata only in the extended attribute " |
| 1407 | "region, but eCryptfs was mounted without " |
| 1408 | "xattr support enabled. eCryptfs will not treat " |
| 1409 | "this like an encrypted file, inode %lu\n", |
| 1410 | ecryptfs_inode->i_ino); |
| 1411 | rc = -EINVAL; |
| 1412 | } |
| 1413 | } |
| 1414 | out: |
| 1415 | if (page_virt) { |
| 1416 | memset(page_virt, 0, PAGE_SIZE); |
| 1417 | kmem_cache_free(ecryptfs_header_cache, page_virt); |
| 1418 | } |
| 1419 | return rc; |
| 1420 | } |
| 1421 | |
| 1422 | /* |
| 1423 | * ecryptfs_encrypt_filename - encrypt filename |
| 1424 | * |
| 1425 | * CBC-encrypts the filename. We do not want to encrypt the same |
| 1426 | * filename with the same key and IV, which may happen with hard |
| 1427 | * links, so we prepend random bits to each filename. |
| 1428 | * |
| 1429 | * Returns zero on success; non-zero otherwise |
| 1430 | */ |
| 1431 | static int |
| 1432 | ecryptfs_encrypt_filename(struct ecryptfs_filename *filename, |
| 1433 | struct ecryptfs_mount_crypt_stat *mount_crypt_stat) |
| 1434 | { |
| 1435 | int rc = 0; |
| 1436 | |
| 1437 | filename->encrypted_filename = NULL; |
| 1438 | filename->encrypted_filename_size = 0; |
| 1439 | if (mount_crypt_stat && (mount_crypt_stat->flags |
| 1440 | & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK)) { |
| 1441 | size_t packet_size; |
| 1442 | size_t remaining_bytes; |
| 1443 | |
| 1444 | rc = ecryptfs_write_tag_70_packet( |
| 1445 | NULL, NULL, |
| 1446 | &filename->encrypted_filename_size, |
| 1447 | mount_crypt_stat, NULL, |
| 1448 | filename->filename_size); |
| 1449 | if (rc) { |
| 1450 | printk(KERN_ERR "%s: Error attempting to get packet " |
| 1451 | "size for tag 72; rc = [%d]\n", __func__, |
| 1452 | rc); |
| 1453 | filename->encrypted_filename_size = 0; |
| 1454 | goto out; |
| 1455 | } |
| 1456 | filename->encrypted_filename = |
| 1457 | kmalloc(filename->encrypted_filename_size, GFP_KERNEL); |
| 1458 | if (!filename->encrypted_filename) { |
| 1459 | rc = -ENOMEM; |
| 1460 | goto out; |
| 1461 | } |
| 1462 | remaining_bytes = filename->encrypted_filename_size; |
| 1463 | rc = ecryptfs_write_tag_70_packet(filename->encrypted_filename, |
| 1464 | &remaining_bytes, |
| 1465 | &packet_size, |
| 1466 | mount_crypt_stat, |
| 1467 | filename->filename, |
| 1468 | filename->filename_size); |
| 1469 | if (rc) { |
| 1470 | printk(KERN_ERR "%s: Error attempting to generate " |
| 1471 | "tag 70 packet; rc = [%d]\n", __func__, |
| 1472 | rc); |
| 1473 | kfree(filename->encrypted_filename); |
| 1474 | filename->encrypted_filename = NULL; |
| 1475 | filename->encrypted_filename_size = 0; |
| 1476 | goto out; |
| 1477 | } |
| 1478 | filename->encrypted_filename_size = packet_size; |
| 1479 | } else { |
| 1480 | printk(KERN_ERR "%s: No support for requested filename " |
| 1481 | "encryption method in this release\n", __func__); |
| 1482 | rc = -EOPNOTSUPP; |
| 1483 | goto out; |
| 1484 | } |
| 1485 | out: |
| 1486 | return rc; |
| 1487 | } |
| 1488 | |
| 1489 | static int ecryptfs_copy_filename(char **copied_name, size_t *copied_name_size, |
| 1490 | const char *name, size_t name_size) |
| 1491 | { |
| 1492 | int rc = 0; |
| 1493 | |
| 1494 | (*copied_name) = kmalloc((name_size + 1), GFP_KERNEL); |
| 1495 | if (!(*copied_name)) { |
| 1496 | rc = -ENOMEM; |
| 1497 | goto out; |
| 1498 | } |
| 1499 | memcpy((void *)(*copied_name), (void *)name, name_size); |
| 1500 | (*copied_name)[(name_size)] = '\0'; /* Only for convenience |
| 1501 | * in printing out the |
| 1502 | * string in debug |
| 1503 | * messages */ |
| 1504 | (*copied_name_size) = name_size; |
| 1505 | out: |
| 1506 | return rc; |
| 1507 | } |
| 1508 | |
| 1509 | /** |
| 1510 | * ecryptfs_process_key_cipher - Perform key cipher initialization. |
| 1511 | * @key_tfm: Crypto context for key material, set by this function |
| 1512 | * @cipher_name: Name of the cipher |
| 1513 | * @key_size: Size of the key in bytes |
| 1514 | * |
| 1515 | * Returns zero on success. Any crypto_tfm structs allocated here |
| 1516 | * should be released by other functions, such as on a superblock put |
| 1517 | * event, regardless of whether this function succeeds for fails. |
| 1518 | */ |
| 1519 | static int |
| 1520 | ecryptfs_process_key_cipher(struct crypto_skcipher **key_tfm, |
| 1521 | char *cipher_name, size_t *key_size) |
| 1522 | { |
| 1523 | char dummy_key[ECRYPTFS_MAX_KEY_BYTES]; |
| 1524 | char *full_alg_name = NULL; |
| 1525 | int rc; |
| 1526 | |
| 1527 | *key_tfm = NULL; |
| 1528 | if (*key_size > ECRYPTFS_MAX_KEY_BYTES) { |
| 1529 | rc = -EINVAL; |
| 1530 | printk(KERN_ERR "Requested key size is [%zd] bytes; maximum " |
| 1531 | "allowable is [%d]\n", *key_size, ECRYPTFS_MAX_KEY_BYTES); |
| 1532 | goto out; |
| 1533 | } |
| 1534 | rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name, cipher_name, |
| 1535 | "ecb"); |
| 1536 | if (rc) |
| 1537 | goto out; |
| 1538 | *key_tfm = crypto_alloc_skcipher(full_alg_name, 0, CRYPTO_ALG_ASYNC); |
| 1539 | if (IS_ERR(*key_tfm)) { |
| 1540 | rc = PTR_ERR(*key_tfm); |
| 1541 | printk(KERN_ERR "Unable to allocate crypto cipher with name " |
| 1542 | "[%s]; rc = [%d]\n", full_alg_name, rc); |
| 1543 | goto out; |
| 1544 | } |
| 1545 | crypto_skcipher_set_flags(*key_tfm, CRYPTO_TFM_REQ_FORBID_WEAK_KEYS); |
| 1546 | if (*key_size == 0) |
| 1547 | *key_size = crypto_skcipher_max_keysize(*key_tfm); |
| 1548 | get_random_bytes(dummy_key, *key_size); |
| 1549 | rc = crypto_skcipher_setkey(*key_tfm, dummy_key, *key_size); |
| 1550 | if (rc) { |
| 1551 | printk(KERN_ERR "Error attempting to set key of size [%zd] for " |
| 1552 | "cipher [%s]; rc = [%d]\n", *key_size, full_alg_name, |
| 1553 | rc); |
| 1554 | rc = -EINVAL; |
| 1555 | goto out; |
| 1556 | } |
| 1557 | out: |
| 1558 | kfree(full_alg_name); |
| 1559 | return rc; |
| 1560 | } |
| 1561 | |
| 1562 | struct kmem_cache *ecryptfs_key_tfm_cache; |
| 1563 | static struct list_head key_tfm_list; |
| 1564 | DEFINE_MUTEX(key_tfm_list_mutex); |
| 1565 | |
| 1566 | int __init ecryptfs_init_crypto(void) |
| 1567 | { |
| 1568 | INIT_LIST_HEAD(&key_tfm_list); |
| 1569 | return 0; |
| 1570 | } |
| 1571 | |
| 1572 | /** |
| 1573 | * ecryptfs_destroy_crypto - free all cached key_tfms on key_tfm_list |
| 1574 | * |
| 1575 | * Called only at module unload time |
| 1576 | */ |
| 1577 | int ecryptfs_destroy_crypto(void) |
| 1578 | { |
| 1579 | struct ecryptfs_key_tfm *key_tfm, *key_tfm_tmp; |
| 1580 | |
| 1581 | mutex_lock(&key_tfm_list_mutex); |
| 1582 | list_for_each_entry_safe(key_tfm, key_tfm_tmp, &key_tfm_list, |
| 1583 | key_tfm_list) { |
| 1584 | list_del(&key_tfm->key_tfm_list); |
| 1585 | crypto_free_skcipher(key_tfm->key_tfm); |
| 1586 | kmem_cache_free(ecryptfs_key_tfm_cache, key_tfm); |
| 1587 | } |
| 1588 | mutex_unlock(&key_tfm_list_mutex); |
| 1589 | return 0; |
| 1590 | } |
| 1591 | |
| 1592 | int |
| 1593 | ecryptfs_add_new_key_tfm(struct ecryptfs_key_tfm **key_tfm, char *cipher_name, |
| 1594 | size_t key_size) |
| 1595 | { |
| 1596 | struct ecryptfs_key_tfm *tmp_tfm; |
| 1597 | int rc = 0; |
| 1598 | |
| 1599 | BUG_ON(!mutex_is_locked(&key_tfm_list_mutex)); |
| 1600 | |
| 1601 | tmp_tfm = kmem_cache_alloc(ecryptfs_key_tfm_cache, GFP_KERNEL); |
| 1602 | if (key_tfm) |
| 1603 | (*key_tfm) = tmp_tfm; |
| 1604 | if (!tmp_tfm) { |
| 1605 | rc = -ENOMEM; |
| 1606 | goto out; |
| 1607 | } |
| 1608 | mutex_init(&tmp_tfm->key_tfm_mutex); |
| 1609 | strscpy(tmp_tfm->cipher_name, cipher_name); |
| 1610 | tmp_tfm->key_size = key_size; |
| 1611 | rc = ecryptfs_process_key_cipher(&tmp_tfm->key_tfm, |
| 1612 | tmp_tfm->cipher_name, |
| 1613 | &tmp_tfm->key_size); |
| 1614 | if (rc) { |
| 1615 | printk(KERN_ERR "Error attempting to initialize key TFM " |
| 1616 | "cipher with name = [%s]; rc = [%d]\n", |
| 1617 | tmp_tfm->cipher_name, rc); |
| 1618 | kmem_cache_free(ecryptfs_key_tfm_cache, tmp_tfm); |
| 1619 | if (key_tfm) |
| 1620 | (*key_tfm) = NULL; |
| 1621 | goto out; |
| 1622 | } |
| 1623 | list_add(&tmp_tfm->key_tfm_list, &key_tfm_list); |
| 1624 | out: |
| 1625 | return rc; |
| 1626 | } |
| 1627 | |
| 1628 | /** |
| 1629 | * ecryptfs_tfm_exists - Search for existing tfm for cipher_name. |
| 1630 | * @cipher_name: the name of the cipher to search for |
| 1631 | * @key_tfm: set to corresponding tfm if found |
| 1632 | * |
| 1633 | * Searches for cached key_tfm matching @cipher_name |
| 1634 | * Must be called with &key_tfm_list_mutex held |
| 1635 | * Returns 1 if found, with @key_tfm set |
| 1636 | * Returns 0 if not found, with @key_tfm set to NULL |
| 1637 | */ |
| 1638 | int ecryptfs_tfm_exists(char *cipher_name, struct ecryptfs_key_tfm **key_tfm) |
| 1639 | { |
| 1640 | struct ecryptfs_key_tfm *tmp_key_tfm; |
| 1641 | |
| 1642 | BUG_ON(!mutex_is_locked(&key_tfm_list_mutex)); |
| 1643 | |
| 1644 | list_for_each_entry(tmp_key_tfm, &key_tfm_list, key_tfm_list) { |
| 1645 | if (strcmp(tmp_key_tfm->cipher_name, cipher_name) == 0) { |
| 1646 | if (key_tfm) |
| 1647 | (*key_tfm) = tmp_key_tfm; |
| 1648 | return 1; |
| 1649 | } |
| 1650 | } |
| 1651 | if (key_tfm) |
| 1652 | (*key_tfm) = NULL; |
| 1653 | return 0; |
| 1654 | } |
| 1655 | |
| 1656 | /** |
| 1657 | * ecryptfs_get_tfm_and_mutex_for_cipher_name |
| 1658 | * |
| 1659 | * @tfm: set to cached tfm found, or new tfm created |
| 1660 | * @tfm_mutex: set to mutex for cached tfm found, or new tfm created |
| 1661 | * @cipher_name: the name of the cipher to search for and/or add |
| 1662 | * |
| 1663 | * Sets pointers to @tfm & @tfm_mutex matching @cipher_name. |
| 1664 | * Searches for cached item first, and creates new if not found. |
| 1665 | * Returns 0 on success, non-zero if adding new cipher failed |
| 1666 | */ |
| 1667 | int ecryptfs_get_tfm_and_mutex_for_cipher_name(struct crypto_skcipher **tfm, |
| 1668 | struct mutex **tfm_mutex, |
| 1669 | char *cipher_name) |
| 1670 | { |
| 1671 | struct ecryptfs_key_tfm *key_tfm; |
| 1672 | int rc = 0; |
| 1673 | |
| 1674 | (*tfm) = NULL; |
| 1675 | (*tfm_mutex) = NULL; |
| 1676 | |
| 1677 | mutex_lock(&key_tfm_list_mutex); |
| 1678 | if (!ecryptfs_tfm_exists(cipher_name, &key_tfm)) { |
| 1679 | rc = ecryptfs_add_new_key_tfm(&key_tfm, cipher_name, 0); |
| 1680 | if (rc) { |
| 1681 | printk(KERN_ERR "Error adding new key_tfm to list; " |
| 1682 | "rc = [%d]\n", rc); |
| 1683 | goto out; |
| 1684 | } |
| 1685 | } |
| 1686 | (*tfm) = key_tfm->key_tfm; |
| 1687 | (*tfm_mutex) = &key_tfm->key_tfm_mutex; |
| 1688 | out: |
| 1689 | mutex_unlock(&key_tfm_list_mutex); |
| 1690 | return rc; |
| 1691 | } |
| 1692 | |
| 1693 | /* 64 characters forming a 6-bit target field */ |
| 1694 | static unsigned char *portable_filename_chars = ("-.0123456789ABCD" |
| 1695 | "EFGHIJKLMNOPQRST" |
| 1696 | "UVWXYZabcdefghij" |
| 1697 | "klmnopqrstuvwxyz"); |
| 1698 | |
| 1699 | /* We could either offset on every reverse map or just pad some 0x00's |
| 1700 | * at the front here */ |
| 1701 | static const unsigned char filename_rev_map[256] = { |
| 1702 | 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 7 */ |
| 1703 | 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 15 */ |
| 1704 | 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 23 */ |
| 1705 | 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 31 */ |
| 1706 | 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 39 */ |
| 1707 | 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, /* 47 */ |
| 1708 | 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, /* 55 */ |
| 1709 | 0x0A, 0x0B, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 63 */ |
| 1710 | 0x00, 0x0C, 0x0D, 0x0E, 0x0F, 0x10, 0x11, 0x12, /* 71 */ |
| 1711 | 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1A, /* 79 */ |
| 1712 | 0x1B, 0x1C, 0x1D, 0x1E, 0x1F, 0x20, 0x21, 0x22, /* 87 */ |
| 1713 | 0x23, 0x24, 0x25, 0x00, 0x00, 0x00, 0x00, 0x00, /* 95 */ |
| 1714 | 0x00, 0x26, 0x27, 0x28, 0x29, 0x2A, 0x2B, 0x2C, /* 103 */ |
| 1715 | 0x2D, 0x2E, 0x2F, 0x30, 0x31, 0x32, 0x33, 0x34, /* 111 */ |
| 1716 | 0x35, 0x36, 0x37, 0x38, 0x39, 0x3A, 0x3B, 0x3C, /* 119 */ |
| 1717 | 0x3D, 0x3E, 0x3F /* 123 - 255 initialized to 0x00 */ |
| 1718 | }; |
| 1719 | |
| 1720 | /** |
| 1721 | * ecryptfs_encode_for_filename |
| 1722 | * @dst: Destination location for encoded filename |
| 1723 | * @dst_size: Size of the encoded filename in bytes |
| 1724 | * @src: Source location for the filename to encode |
| 1725 | * @src_size: Size of the source in bytes |
| 1726 | */ |
| 1727 | static void ecryptfs_encode_for_filename(unsigned char *dst, size_t *dst_size, |
| 1728 | unsigned char *src, size_t src_size) |
| 1729 | { |
| 1730 | size_t num_blocks; |
| 1731 | size_t block_num = 0; |
| 1732 | size_t dst_offset = 0; |
| 1733 | unsigned char last_block[3]; |
| 1734 | |
| 1735 | if (src_size == 0) { |
| 1736 | (*dst_size) = 0; |
| 1737 | goto out; |
| 1738 | } |
| 1739 | num_blocks = (src_size / 3); |
| 1740 | if ((src_size % 3) == 0) { |
| 1741 | memcpy(last_block, (&src[src_size - 3]), 3); |
| 1742 | } else { |
| 1743 | num_blocks++; |
| 1744 | last_block[2] = 0x00; |
| 1745 | switch (src_size % 3) { |
| 1746 | case 1: |
| 1747 | last_block[0] = src[src_size - 1]; |
| 1748 | last_block[1] = 0x00; |
| 1749 | break; |
| 1750 | case 2: |
| 1751 | last_block[0] = src[src_size - 2]; |
| 1752 | last_block[1] = src[src_size - 1]; |
| 1753 | } |
| 1754 | } |
| 1755 | (*dst_size) = (num_blocks * 4); |
| 1756 | if (!dst) |
| 1757 | goto out; |
| 1758 | while (block_num < num_blocks) { |
| 1759 | unsigned char *src_block; |
| 1760 | unsigned char dst_block[4]; |
| 1761 | |
| 1762 | if (block_num == (num_blocks - 1)) |
| 1763 | src_block = last_block; |
| 1764 | else |
| 1765 | src_block = &src[block_num * 3]; |
| 1766 | dst_block[0] = ((src_block[0] >> 2) & 0x3F); |
| 1767 | dst_block[1] = (((src_block[0] << 4) & 0x30) |
| 1768 | | ((src_block[1] >> 4) & 0x0F)); |
| 1769 | dst_block[2] = (((src_block[1] << 2) & 0x3C) |
| 1770 | | ((src_block[2] >> 6) & 0x03)); |
| 1771 | dst_block[3] = (src_block[2] & 0x3F); |
| 1772 | dst[dst_offset++] = portable_filename_chars[dst_block[0]]; |
| 1773 | dst[dst_offset++] = portable_filename_chars[dst_block[1]]; |
| 1774 | dst[dst_offset++] = portable_filename_chars[dst_block[2]]; |
| 1775 | dst[dst_offset++] = portable_filename_chars[dst_block[3]]; |
| 1776 | block_num++; |
| 1777 | } |
| 1778 | out: |
| 1779 | return; |
| 1780 | } |
| 1781 | |
| 1782 | static size_t ecryptfs_max_decoded_size(size_t encoded_size) |
| 1783 | { |
| 1784 | /* Not exact; conservatively long. Every block of 4 |
| 1785 | * encoded characters decodes into a block of 3 |
| 1786 | * decoded characters. This segment of code provides |
| 1787 | * the caller with the maximum amount of allocated |
| 1788 | * space that @dst will need to point to in a |
| 1789 | * subsequent call. */ |
| 1790 | return ((encoded_size + 1) * 3) / 4; |
| 1791 | } |
| 1792 | |
| 1793 | /** |
| 1794 | * ecryptfs_decode_from_filename |
| 1795 | * @dst: If NULL, this function only sets @dst_size and returns. If |
| 1796 | * non-NULL, this function decodes the encoded octets in @src |
| 1797 | * into the memory that @dst points to. |
| 1798 | * @dst_size: Set to the size of the decoded string. |
| 1799 | * @src: The encoded set of octets to decode. |
| 1800 | * @src_size: The size of the encoded set of octets to decode. |
| 1801 | */ |
| 1802 | static void |
| 1803 | ecryptfs_decode_from_filename(unsigned char *dst, size_t *dst_size, |
| 1804 | const unsigned char *src, size_t src_size) |
| 1805 | { |
| 1806 | u8 current_bit_offset = 0; |
| 1807 | size_t src_byte_offset = 0; |
| 1808 | size_t dst_byte_offset = 0; |
| 1809 | |
| 1810 | if (!dst) { |
| 1811 | (*dst_size) = ecryptfs_max_decoded_size(src_size); |
| 1812 | goto out; |
| 1813 | } |
| 1814 | while (src_byte_offset < src_size) { |
| 1815 | unsigned char src_byte = |
| 1816 | filename_rev_map[(int)src[src_byte_offset]]; |
| 1817 | |
| 1818 | switch (current_bit_offset) { |
| 1819 | case 0: |
| 1820 | dst[dst_byte_offset] = (src_byte << 2); |
| 1821 | current_bit_offset = 6; |
| 1822 | break; |
| 1823 | case 6: |
| 1824 | dst[dst_byte_offset++] |= (src_byte >> 4); |
| 1825 | dst[dst_byte_offset] = ((src_byte & 0xF) |
| 1826 | << 4); |
| 1827 | current_bit_offset = 4; |
| 1828 | break; |
| 1829 | case 4: |
| 1830 | dst[dst_byte_offset++] |= (src_byte >> 2); |
| 1831 | dst[dst_byte_offset] = (src_byte << 6); |
| 1832 | current_bit_offset = 2; |
| 1833 | break; |
| 1834 | case 2: |
| 1835 | dst[dst_byte_offset++] |= (src_byte); |
| 1836 | current_bit_offset = 0; |
| 1837 | break; |
| 1838 | } |
| 1839 | src_byte_offset++; |
| 1840 | } |
| 1841 | (*dst_size) = dst_byte_offset; |
| 1842 | out: |
| 1843 | return; |
| 1844 | } |
| 1845 | |
| 1846 | /** |
| 1847 | * ecryptfs_encrypt_and_encode_filename - converts a plaintext file name to cipher text |
| 1848 | * @encoded_name: The encrypted name |
| 1849 | * @encoded_name_size: Length of the encrypted name |
| 1850 | * @mount_crypt_stat: The crypt_stat struct associated with the file name to encode |
| 1851 | * @name: The plaintext name |
| 1852 | * @name_size: The length of the plaintext name |
| 1853 | * |
| 1854 | * Encrypts and encodes a filename into something that constitutes a |
| 1855 | * valid filename for a filesystem, with printable characters. |
| 1856 | * |
| 1857 | * We assume that we have a properly initialized crypto context, |
| 1858 | * pointed to by crypt_stat->tfm. |
| 1859 | * |
| 1860 | * Returns zero on success; non-zero on otherwise |
| 1861 | */ |
| 1862 | int ecryptfs_encrypt_and_encode_filename( |
| 1863 | char **encoded_name, |
| 1864 | size_t *encoded_name_size, |
| 1865 | struct ecryptfs_mount_crypt_stat *mount_crypt_stat, |
| 1866 | const char *name, size_t name_size) |
| 1867 | { |
| 1868 | size_t encoded_name_no_prefix_size; |
| 1869 | int rc = 0; |
| 1870 | |
| 1871 | (*encoded_name) = NULL; |
| 1872 | (*encoded_name_size) = 0; |
| 1873 | if (mount_crypt_stat && (mount_crypt_stat->flags |
| 1874 | & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)) { |
| 1875 | struct ecryptfs_filename *filename; |
| 1876 | |
| 1877 | filename = kzalloc(sizeof(*filename), GFP_KERNEL); |
| 1878 | if (!filename) { |
| 1879 | rc = -ENOMEM; |
| 1880 | goto out; |
| 1881 | } |
| 1882 | filename->filename = (char *)name; |
| 1883 | filename->filename_size = name_size; |
| 1884 | rc = ecryptfs_encrypt_filename(filename, mount_crypt_stat); |
| 1885 | if (rc) { |
| 1886 | printk(KERN_ERR "%s: Error attempting to encrypt " |
| 1887 | "filename; rc = [%d]\n", __func__, rc); |
| 1888 | kfree(filename); |
| 1889 | goto out; |
| 1890 | } |
| 1891 | ecryptfs_encode_for_filename( |
| 1892 | NULL, &encoded_name_no_prefix_size, |
| 1893 | filename->encrypted_filename, |
| 1894 | filename->encrypted_filename_size); |
| 1895 | if (mount_crypt_stat |
| 1896 | && (mount_crypt_stat->flags |
| 1897 | & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK)) |
| 1898 | (*encoded_name_size) = |
| 1899 | (ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE |
| 1900 | + encoded_name_no_prefix_size); |
| 1901 | else |
| 1902 | (*encoded_name_size) = |
| 1903 | (ECRYPTFS_FEK_ENCRYPTED_FILENAME_PREFIX_SIZE |
| 1904 | + encoded_name_no_prefix_size); |
| 1905 | (*encoded_name) = kmalloc((*encoded_name_size) + 1, GFP_KERNEL); |
| 1906 | if (!(*encoded_name)) { |
| 1907 | rc = -ENOMEM; |
| 1908 | kfree(filename->encrypted_filename); |
| 1909 | kfree(filename); |
| 1910 | goto out; |
| 1911 | } |
| 1912 | if (mount_crypt_stat |
| 1913 | && (mount_crypt_stat->flags |
| 1914 | & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK)) { |
| 1915 | memcpy((*encoded_name), |
| 1916 | ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX, |
| 1917 | ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE); |
| 1918 | ecryptfs_encode_for_filename( |
| 1919 | ((*encoded_name) |
| 1920 | + ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE), |
| 1921 | &encoded_name_no_prefix_size, |
| 1922 | filename->encrypted_filename, |
| 1923 | filename->encrypted_filename_size); |
| 1924 | (*encoded_name_size) = |
| 1925 | (ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE |
| 1926 | + encoded_name_no_prefix_size); |
| 1927 | (*encoded_name)[(*encoded_name_size)] = '\0'; |
| 1928 | } else { |
| 1929 | rc = -EOPNOTSUPP; |
| 1930 | } |
| 1931 | if (rc) { |
| 1932 | printk(KERN_ERR "%s: Error attempting to encode " |
| 1933 | "encrypted filename; rc = [%d]\n", __func__, |
| 1934 | rc); |
| 1935 | kfree((*encoded_name)); |
| 1936 | (*encoded_name) = NULL; |
| 1937 | (*encoded_name_size) = 0; |
| 1938 | } |
| 1939 | kfree(filename->encrypted_filename); |
| 1940 | kfree(filename); |
| 1941 | } else { |
| 1942 | rc = ecryptfs_copy_filename(encoded_name, |
| 1943 | encoded_name_size, |
| 1944 | name, name_size); |
| 1945 | } |
| 1946 | out: |
| 1947 | return rc; |
| 1948 | } |
| 1949 | |
| 1950 | /** |
| 1951 | * ecryptfs_decode_and_decrypt_filename - converts the encoded cipher text name to decoded plaintext |
| 1952 | * @plaintext_name: The plaintext name |
| 1953 | * @plaintext_name_size: The plaintext name size |
| 1954 | * @sb: Ecryptfs's super_block |
| 1955 | * @name: The filename in cipher text |
| 1956 | * @name_size: The cipher text name size |
| 1957 | * |
| 1958 | * Decrypts and decodes the filename. |
| 1959 | * |
| 1960 | * Returns zero on error; non-zero otherwise |
| 1961 | */ |
| 1962 | int ecryptfs_decode_and_decrypt_filename(char **plaintext_name, |
| 1963 | size_t *plaintext_name_size, |
| 1964 | struct super_block *sb, |
| 1965 | const char *name, size_t name_size) |
| 1966 | { |
| 1967 | struct ecryptfs_mount_crypt_stat *mount_crypt_stat = |
| 1968 | &ecryptfs_superblock_to_private(sb)->mount_crypt_stat; |
| 1969 | char *decoded_name; |
| 1970 | size_t decoded_name_size; |
| 1971 | size_t packet_size; |
| 1972 | int rc = 0; |
| 1973 | |
| 1974 | if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) && |
| 1975 | !(mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)) { |
| 1976 | if (is_dot_dotdot(name, name_size)) { |
| 1977 | rc = ecryptfs_copy_filename(plaintext_name, |
| 1978 | plaintext_name_size, |
| 1979 | name, name_size); |
| 1980 | goto out; |
| 1981 | } |
| 1982 | |
| 1983 | if (name_size <= ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE || |
| 1984 | strncmp(name, ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX, |
| 1985 | ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE)) { |
| 1986 | rc = -EINVAL; |
| 1987 | goto out; |
| 1988 | } |
| 1989 | |
| 1990 | name += ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE; |
| 1991 | name_size -= ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE; |
| 1992 | ecryptfs_decode_from_filename(NULL, &decoded_name_size, |
| 1993 | name, name_size); |
| 1994 | decoded_name = kmalloc(decoded_name_size, GFP_KERNEL); |
| 1995 | if (!decoded_name) { |
| 1996 | rc = -ENOMEM; |
| 1997 | goto out; |
| 1998 | } |
| 1999 | ecryptfs_decode_from_filename(decoded_name, &decoded_name_size, |
| 2000 | name, name_size); |
| 2001 | rc = ecryptfs_parse_tag_70_packet(plaintext_name, |
| 2002 | plaintext_name_size, |
| 2003 | &packet_size, |
| 2004 | mount_crypt_stat, |
| 2005 | decoded_name, |
| 2006 | decoded_name_size); |
| 2007 | if (rc) { |
| 2008 | ecryptfs_printk(KERN_DEBUG, |
| 2009 | "%s: Could not parse tag 70 packet from filename\n", |
| 2010 | __func__); |
| 2011 | goto out_free; |
| 2012 | } |
| 2013 | } else { |
| 2014 | rc = ecryptfs_copy_filename(plaintext_name, |
| 2015 | plaintext_name_size, |
| 2016 | name, name_size); |
| 2017 | goto out; |
| 2018 | } |
| 2019 | out_free: |
| 2020 | kfree(decoded_name); |
| 2021 | out: |
| 2022 | return rc; |
| 2023 | } |
| 2024 | |
| 2025 | #define ENC_NAME_MAX_BLOCKLEN_8_OR_16 143 |
| 2026 | |
| 2027 | int ecryptfs_set_f_namelen(long *namelen, long lower_namelen, |
| 2028 | struct ecryptfs_mount_crypt_stat *mount_crypt_stat) |
| 2029 | { |
| 2030 | struct crypto_skcipher *tfm; |
| 2031 | struct mutex *tfm_mutex; |
| 2032 | size_t cipher_blocksize; |
| 2033 | int rc; |
| 2034 | |
| 2035 | if (!(mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)) { |
| 2036 | (*namelen) = lower_namelen; |
| 2037 | return 0; |
| 2038 | } |
| 2039 | |
| 2040 | rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&tfm, &tfm_mutex, |
| 2041 | mount_crypt_stat->global_default_fn_cipher_name); |
| 2042 | if (unlikely(rc)) { |
| 2043 | (*namelen) = 0; |
| 2044 | return rc; |
| 2045 | } |
| 2046 | |
| 2047 | mutex_lock(tfm_mutex); |
| 2048 | cipher_blocksize = crypto_skcipher_blocksize(tfm); |
| 2049 | mutex_unlock(tfm_mutex); |
| 2050 | |
| 2051 | /* Return an exact amount for the common cases */ |
| 2052 | if (lower_namelen == NAME_MAX |
| 2053 | && (cipher_blocksize == 8 || cipher_blocksize == 16)) { |
| 2054 | (*namelen) = ENC_NAME_MAX_BLOCKLEN_8_OR_16; |
| 2055 | return 0; |
| 2056 | } |
| 2057 | |
| 2058 | /* Return a safe estimate for the uncommon cases */ |
| 2059 | (*namelen) = lower_namelen; |
| 2060 | (*namelen) -= ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE; |
| 2061 | /* Since this is the max decoded size, subtract 1 "decoded block" len */ |
| 2062 | (*namelen) = ecryptfs_max_decoded_size(*namelen) - 3; |
| 2063 | (*namelen) -= ECRYPTFS_TAG_70_MAX_METADATA_SIZE; |
| 2064 | (*namelen) -= ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES; |
| 2065 | /* Worst case is that the filename is padded nearly a full block size */ |
| 2066 | (*namelen) -= cipher_blocksize - 1; |
| 2067 | |
| 2068 | if ((*namelen) < 0) |
| 2069 | (*namelen) = 0; |
| 2070 | |
| 2071 | return 0; |
| 2072 | } |