Michael Halcrow | 237fead | 2006-10-04 02:16:22 -0700 | [diff] [blame] | 1 | /** |
| 2 | * eCryptfs: Linux filesystem encryption layer |
| 3 | * |
| 4 | * Copyright (C) 1997-2004 Erez Zadok |
| 5 | * Copyright (C) 2001-2004 Stony Brook University |
| 6 | * Copyright (C) 2004-2006 International Business Machines Corp. |
| 7 | * Author(s): Michael A. Halcrow <mahalcro@us.ibm.com> |
| 8 | * Michael C. Thompson <mcthomps@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 | #include <linux/fs.h> |
| 27 | #include <linux/mount.h> |
| 28 | #include <linux/pagemap.h> |
| 29 | #include <linux/random.h> |
| 30 | #include <linux/compiler.h> |
| 31 | #include <linux/key.h> |
| 32 | #include <linux/namei.h> |
| 33 | #include <linux/crypto.h> |
| 34 | #include <linux/file.h> |
| 35 | #include <linux/scatterlist.h> |
| 36 | #include "ecryptfs_kernel.h" |
| 37 | |
| 38 | static int |
| 39 | ecryptfs_decrypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat, |
| 40 | struct page *dst_page, int dst_offset, |
| 41 | struct page *src_page, int src_offset, int size, |
| 42 | unsigned char *iv); |
| 43 | static int |
| 44 | ecryptfs_encrypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat, |
| 45 | struct page *dst_page, int dst_offset, |
| 46 | struct page *src_page, int src_offset, int size, |
| 47 | unsigned char *iv); |
| 48 | |
| 49 | /** |
| 50 | * ecryptfs_to_hex |
| 51 | * @dst: Buffer to take hex character representation of contents of |
| 52 | * src; must be at least of size (src_size * 2) |
| 53 | * @src: Buffer to be converted to a hex string respresentation |
| 54 | * @src_size: number of bytes to convert |
| 55 | */ |
| 56 | void ecryptfs_to_hex(char *dst, char *src, size_t src_size) |
| 57 | { |
| 58 | int x; |
| 59 | |
| 60 | for (x = 0; x < src_size; x++) |
| 61 | sprintf(&dst[x * 2], "%.2x", (unsigned char)src[x]); |
| 62 | } |
| 63 | |
| 64 | /** |
| 65 | * ecryptfs_from_hex |
| 66 | * @dst: Buffer to take the bytes from src hex; must be at least of |
| 67 | * size (src_size / 2) |
| 68 | * @src: Buffer to be converted from a hex string respresentation to raw value |
| 69 | * @dst_size: size of dst buffer, or number of hex characters pairs to convert |
| 70 | */ |
| 71 | void ecryptfs_from_hex(char *dst, char *src, int dst_size) |
| 72 | { |
| 73 | int x; |
| 74 | char tmp[3] = { 0, }; |
| 75 | |
| 76 | for (x = 0; x < dst_size; x++) { |
| 77 | tmp[0] = src[x * 2]; |
| 78 | tmp[1] = src[x * 2 + 1]; |
| 79 | dst[x] = (unsigned char)simple_strtol(tmp, NULL, 16); |
| 80 | } |
| 81 | } |
| 82 | |
| 83 | /** |
| 84 | * ecryptfs_calculate_md5 - calculates the md5 of @src |
| 85 | * @dst: Pointer to 16 bytes of allocated memory |
| 86 | * @crypt_stat: Pointer to crypt_stat struct for the current inode |
| 87 | * @src: Data to be md5'd |
| 88 | * @len: Length of @src |
| 89 | * |
| 90 | * Uses the allocated crypto context that crypt_stat references to |
| 91 | * generate the MD5 sum of the contents of src. |
| 92 | */ |
| 93 | static int ecryptfs_calculate_md5(char *dst, |
| 94 | struct ecryptfs_crypt_stat *crypt_stat, |
| 95 | char *src, int len) |
| 96 | { |
Michael Halcrow | 237fead | 2006-10-04 02:16:22 -0700 | [diff] [blame] | 97 | struct scatterlist sg; |
Michael Halcrow | 565d9724 | 2006-10-30 22:07:17 -0800 | [diff] [blame] | 98 | struct hash_desc desc = { |
| 99 | .tfm = crypt_stat->hash_tfm, |
| 100 | .flags = CRYPTO_TFM_REQ_MAY_SLEEP |
| 101 | }; |
| 102 | int rc = 0; |
Michael Halcrow | 237fead | 2006-10-04 02:16:22 -0700 | [diff] [blame] | 103 | |
Michael Halcrow | 565d9724 | 2006-10-30 22:07:17 -0800 | [diff] [blame] | 104 | mutex_lock(&crypt_stat->cs_hash_tfm_mutex); |
Michael Halcrow | 237fead | 2006-10-04 02:16:22 -0700 | [diff] [blame] | 105 | sg_init_one(&sg, (u8 *)src, len); |
Michael Halcrow | 565d9724 | 2006-10-30 22:07:17 -0800 | [diff] [blame] | 106 | if (!desc.tfm) { |
| 107 | desc.tfm = crypto_alloc_hash(ECRYPTFS_DEFAULT_HASH, 0, |
| 108 | CRYPTO_ALG_ASYNC); |
| 109 | if (IS_ERR(desc.tfm)) { |
| 110 | rc = PTR_ERR(desc.tfm); |
Michael Halcrow | 237fead | 2006-10-04 02:16:22 -0700 | [diff] [blame] | 111 | ecryptfs_printk(KERN_ERR, "Error attempting to " |
Michael Halcrow | 565d9724 | 2006-10-30 22:07:17 -0800 | [diff] [blame] | 112 | "allocate crypto context; rc = [%d]\n", |
| 113 | rc); |
Michael Halcrow | 237fead | 2006-10-04 02:16:22 -0700 | [diff] [blame] | 114 | goto out; |
| 115 | } |
Michael Halcrow | 565d9724 | 2006-10-30 22:07:17 -0800 | [diff] [blame] | 116 | crypt_stat->hash_tfm = desc.tfm; |
Michael Halcrow | 237fead | 2006-10-04 02:16:22 -0700 | [diff] [blame] | 117 | } |
Michael Halcrow | 565d9724 | 2006-10-30 22:07:17 -0800 | [diff] [blame] | 118 | crypto_hash_init(&desc); |
| 119 | crypto_hash_update(&desc, &sg, len); |
| 120 | crypto_hash_final(&desc, dst); |
| 121 | mutex_unlock(&crypt_stat->cs_hash_tfm_mutex); |
Michael Halcrow | 237fead | 2006-10-04 02:16:22 -0700 | [diff] [blame] | 122 | out: |
| 123 | return rc; |
| 124 | } |
| 125 | |
Michael Halcrow | 8bba066 | 2006-10-30 22:07:18 -0800 | [diff] [blame] | 126 | int ecryptfs_crypto_api_algify_cipher_name(char **algified_name, |
| 127 | char *cipher_name, |
| 128 | char *chaining_modifier) |
| 129 | { |
| 130 | int cipher_name_len = strlen(cipher_name); |
| 131 | int chaining_modifier_len = strlen(chaining_modifier); |
| 132 | int algified_name_len; |
| 133 | int rc; |
| 134 | |
| 135 | algified_name_len = (chaining_modifier_len + cipher_name_len + 3); |
| 136 | (*algified_name) = kmalloc(algified_name_len, GFP_KERNEL); |
Michael Halcrow | 7bd473f | 2006-11-02 22:06:56 -0800 | [diff] [blame] | 137 | if (!(*algified_name)) { |
Michael Halcrow | 8bba066 | 2006-10-30 22:07:18 -0800 | [diff] [blame] | 138 | rc = -ENOMEM; |
| 139 | goto out; |
| 140 | } |
| 141 | snprintf((*algified_name), algified_name_len, "%s(%s)", |
| 142 | chaining_modifier, cipher_name); |
| 143 | rc = 0; |
| 144 | out: |
| 145 | return rc; |
| 146 | } |
| 147 | |
Michael Halcrow | 237fead | 2006-10-04 02:16:22 -0700 | [diff] [blame] | 148 | /** |
| 149 | * ecryptfs_derive_iv |
| 150 | * @iv: destination for the derived iv vale |
| 151 | * @crypt_stat: Pointer to crypt_stat struct for the current inode |
| 152 | * @offset: Offset of the page whose's iv we are to derive |
| 153 | * |
| 154 | * Generate the initialization vector from the given root IV and page |
| 155 | * offset. |
| 156 | * |
| 157 | * Returns zero on success; non-zero on error. |
| 158 | */ |
| 159 | static int ecryptfs_derive_iv(char *iv, struct ecryptfs_crypt_stat *crypt_stat, |
| 160 | pgoff_t offset) |
| 161 | { |
| 162 | int rc = 0; |
| 163 | char dst[MD5_DIGEST_SIZE]; |
| 164 | char src[ECRYPTFS_MAX_IV_BYTES + 16]; |
| 165 | |
| 166 | if (unlikely(ecryptfs_verbosity > 0)) { |
| 167 | ecryptfs_printk(KERN_DEBUG, "root iv:\n"); |
| 168 | ecryptfs_dump_hex(crypt_stat->root_iv, crypt_stat->iv_bytes); |
| 169 | } |
| 170 | /* TODO: It is probably secure to just cast the least |
| 171 | * significant bits of the root IV into an unsigned long and |
| 172 | * add the offset to that rather than go through all this |
| 173 | * hashing business. -Halcrow */ |
| 174 | memcpy(src, crypt_stat->root_iv, crypt_stat->iv_bytes); |
| 175 | memset((src + crypt_stat->iv_bytes), 0, 16); |
| 176 | snprintf((src + crypt_stat->iv_bytes), 16, "%ld", offset); |
| 177 | if (unlikely(ecryptfs_verbosity > 0)) { |
| 178 | ecryptfs_printk(KERN_DEBUG, "source:\n"); |
| 179 | ecryptfs_dump_hex(src, (crypt_stat->iv_bytes + 16)); |
| 180 | } |
| 181 | rc = ecryptfs_calculate_md5(dst, crypt_stat, src, |
| 182 | (crypt_stat->iv_bytes + 16)); |
| 183 | if (rc) { |
| 184 | ecryptfs_printk(KERN_WARNING, "Error attempting to compute " |
| 185 | "MD5 while generating IV for a page\n"); |
| 186 | goto out; |
| 187 | } |
| 188 | memcpy(iv, dst, crypt_stat->iv_bytes); |
| 189 | if (unlikely(ecryptfs_verbosity > 0)) { |
| 190 | ecryptfs_printk(KERN_DEBUG, "derived iv:\n"); |
| 191 | ecryptfs_dump_hex(iv, crypt_stat->iv_bytes); |
| 192 | } |
| 193 | out: |
| 194 | return rc; |
| 195 | } |
| 196 | |
| 197 | /** |
| 198 | * ecryptfs_init_crypt_stat |
| 199 | * @crypt_stat: Pointer to the crypt_stat struct to initialize. |
| 200 | * |
| 201 | * Initialize the crypt_stat structure. |
| 202 | */ |
| 203 | void |
| 204 | ecryptfs_init_crypt_stat(struct ecryptfs_crypt_stat *crypt_stat) |
| 205 | { |
| 206 | memset((void *)crypt_stat, 0, sizeof(struct ecryptfs_crypt_stat)); |
| 207 | mutex_init(&crypt_stat->cs_mutex); |
| 208 | mutex_init(&crypt_stat->cs_tfm_mutex); |
Michael Halcrow | 565d9724 | 2006-10-30 22:07:17 -0800 | [diff] [blame] | 209 | mutex_init(&crypt_stat->cs_hash_tfm_mutex); |
Michael Halcrow | 237fead | 2006-10-04 02:16:22 -0700 | [diff] [blame] | 210 | ECRYPTFS_SET_FLAG(crypt_stat->flags, ECRYPTFS_STRUCT_INITIALIZED); |
| 211 | } |
| 212 | |
| 213 | /** |
| 214 | * ecryptfs_destruct_crypt_stat |
| 215 | * @crypt_stat: Pointer to the crypt_stat struct to initialize. |
| 216 | * |
| 217 | * Releases all memory associated with a crypt_stat struct. |
| 218 | */ |
| 219 | void ecryptfs_destruct_crypt_stat(struct ecryptfs_crypt_stat *crypt_stat) |
| 220 | { |
| 221 | if (crypt_stat->tfm) |
Michael Halcrow | 8bba066 | 2006-10-30 22:07:18 -0800 | [diff] [blame] | 222 | crypto_free_blkcipher(crypt_stat->tfm); |
Michael Halcrow | 565d9724 | 2006-10-30 22:07:17 -0800 | [diff] [blame] | 223 | if (crypt_stat->hash_tfm) |
| 224 | crypto_free_hash(crypt_stat->hash_tfm); |
Michael Halcrow | 237fead | 2006-10-04 02:16:22 -0700 | [diff] [blame] | 225 | memset(crypt_stat, 0, sizeof(struct ecryptfs_crypt_stat)); |
| 226 | } |
| 227 | |
| 228 | void ecryptfs_destruct_mount_crypt_stat( |
| 229 | struct ecryptfs_mount_crypt_stat *mount_crypt_stat) |
| 230 | { |
| 231 | if (mount_crypt_stat->global_auth_tok_key) |
| 232 | key_put(mount_crypt_stat->global_auth_tok_key); |
| 233 | if (mount_crypt_stat->global_key_tfm) |
Michael Halcrow | 8bba066 | 2006-10-30 22:07:18 -0800 | [diff] [blame] | 234 | crypto_free_blkcipher(mount_crypt_stat->global_key_tfm); |
Michael Halcrow | 237fead | 2006-10-04 02:16:22 -0700 | [diff] [blame] | 235 | memset(mount_crypt_stat, 0, sizeof(struct ecryptfs_mount_crypt_stat)); |
| 236 | } |
| 237 | |
| 238 | /** |
| 239 | * virt_to_scatterlist |
| 240 | * @addr: Virtual address |
| 241 | * @size: Size of data; should be an even multiple of the block size |
| 242 | * @sg: Pointer to scatterlist array; set to NULL to obtain only |
| 243 | * the number of scatterlist structs required in array |
| 244 | * @sg_size: Max array size |
| 245 | * |
| 246 | * Fills in a scatterlist array with page references for a passed |
| 247 | * virtual address. |
| 248 | * |
| 249 | * Returns the number of scatterlist structs in array used |
| 250 | */ |
| 251 | int virt_to_scatterlist(const void *addr, int size, struct scatterlist *sg, |
| 252 | int sg_size) |
| 253 | { |
| 254 | int i = 0; |
| 255 | struct page *pg; |
| 256 | int offset; |
| 257 | int remainder_of_page; |
| 258 | |
| 259 | while (size > 0 && i < sg_size) { |
| 260 | pg = virt_to_page(addr); |
| 261 | offset = offset_in_page(addr); |
| 262 | if (sg) { |
| 263 | sg[i].page = pg; |
| 264 | sg[i].offset = offset; |
| 265 | } |
| 266 | remainder_of_page = PAGE_CACHE_SIZE - offset; |
| 267 | if (size >= remainder_of_page) { |
| 268 | if (sg) |
| 269 | sg[i].length = remainder_of_page; |
| 270 | addr += remainder_of_page; |
| 271 | size -= remainder_of_page; |
| 272 | } else { |
| 273 | if (sg) |
| 274 | sg[i].length = size; |
| 275 | addr += size; |
| 276 | size = 0; |
| 277 | } |
| 278 | i++; |
| 279 | } |
| 280 | if (size > 0) |
| 281 | return -ENOMEM; |
| 282 | return i; |
| 283 | } |
| 284 | |
| 285 | /** |
| 286 | * encrypt_scatterlist |
| 287 | * @crypt_stat: Pointer to the crypt_stat struct to initialize. |
| 288 | * @dest_sg: Destination of encrypted data |
| 289 | * @src_sg: Data to be encrypted |
| 290 | * @size: Length of data to be encrypted |
| 291 | * @iv: iv to use during encryption |
| 292 | * |
| 293 | * Returns the number of bytes encrypted; negative value on error |
| 294 | */ |
| 295 | static int encrypt_scatterlist(struct ecryptfs_crypt_stat *crypt_stat, |
| 296 | struct scatterlist *dest_sg, |
| 297 | struct scatterlist *src_sg, int size, |
| 298 | unsigned char *iv) |
| 299 | { |
Michael Halcrow | 8bba066 | 2006-10-30 22:07:18 -0800 | [diff] [blame] | 300 | struct blkcipher_desc desc = { |
| 301 | .tfm = crypt_stat->tfm, |
| 302 | .info = iv, |
| 303 | .flags = CRYPTO_TFM_REQ_MAY_SLEEP |
| 304 | }; |
Michael Halcrow | 237fead | 2006-10-04 02:16:22 -0700 | [diff] [blame] | 305 | int rc = 0; |
| 306 | |
| 307 | BUG_ON(!crypt_stat || !crypt_stat->tfm |
| 308 | || !ECRYPTFS_CHECK_FLAG(crypt_stat->flags, |
| 309 | ECRYPTFS_STRUCT_INITIALIZED)); |
| 310 | if (unlikely(ecryptfs_verbosity > 0)) { |
| 311 | ecryptfs_printk(KERN_DEBUG, "Key size [%d]; key:\n", |
| 312 | crypt_stat->key_size); |
| 313 | ecryptfs_dump_hex(crypt_stat->key, |
| 314 | crypt_stat->key_size); |
| 315 | } |
| 316 | /* Consider doing this once, when the file is opened */ |
| 317 | mutex_lock(&crypt_stat->cs_tfm_mutex); |
Michael Halcrow | 8bba066 | 2006-10-30 22:07:18 -0800 | [diff] [blame] | 318 | rc = crypto_blkcipher_setkey(crypt_stat->tfm, crypt_stat->key, |
| 319 | crypt_stat->key_size); |
Michael Halcrow | 237fead | 2006-10-04 02:16:22 -0700 | [diff] [blame] | 320 | if (rc) { |
| 321 | ecryptfs_printk(KERN_ERR, "Error setting key; rc = [%d]\n", |
| 322 | rc); |
| 323 | mutex_unlock(&crypt_stat->cs_tfm_mutex); |
| 324 | rc = -EINVAL; |
| 325 | goto out; |
| 326 | } |
| 327 | ecryptfs_printk(KERN_DEBUG, "Encrypting [%d] bytes.\n", size); |
Michael Halcrow | 8bba066 | 2006-10-30 22:07:18 -0800 | [diff] [blame] | 328 | crypto_blkcipher_encrypt_iv(&desc, dest_sg, src_sg, size); |
Michael Halcrow | 237fead | 2006-10-04 02:16:22 -0700 | [diff] [blame] | 329 | mutex_unlock(&crypt_stat->cs_tfm_mutex); |
| 330 | out: |
| 331 | return rc; |
| 332 | } |
| 333 | |
| 334 | static void |
| 335 | ecryptfs_extent_to_lwr_pg_idx_and_offset(unsigned long *lower_page_idx, |
| 336 | int *byte_offset, |
| 337 | struct ecryptfs_crypt_stat *crypt_stat, |
| 338 | unsigned long extent_num) |
| 339 | { |
| 340 | unsigned long lower_extent_num; |
| 341 | int extents_occupied_by_headers_at_front; |
| 342 | int bytes_occupied_by_headers_at_front; |
| 343 | int extent_offset; |
| 344 | int extents_per_page; |
| 345 | |
| 346 | bytes_occupied_by_headers_at_front = |
| 347 | ( crypt_stat->header_extent_size |
| 348 | * crypt_stat->num_header_extents_at_front ); |
| 349 | extents_occupied_by_headers_at_front = |
| 350 | ( bytes_occupied_by_headers_at_front |
| 351 | / crypt_stat->extent_size ); |
| 352 | lower_extent_num = extents_occupied_by_headers_at_front + extent_num; |
| 353 | extents_per_page = PAGE_CACHE_SIZE / crypt_stat->extent_size; |
| 354 | (*lower_page_idx) = lower_extent_num / extents_per_page; |
| 355 | extent_offset = lower_extent_num % extents_per_page; |
| 356 | (*byte_offset) = extent_offset * crypt_stat->extent_size; |
| 357 | ecryptfs_printk(KERN_DEBUG, " * crypt_stat->header_extent_size = " |
| 358 | "[%d]\n", crypt_stat->header_extent_size); |
| 359 | ecryptfs_printk(KERN_DEBUG, " * crypt_stat->" |
| 360 | "num_header_extents_at_front = [%d]\n", |
| 361 | crypt_stat->num_header_extents_at_front); |
| 362 | ecryptfs_printk(KERN_DEBUG, " * extents_occupied_by_headers_at_" |
| 363 | "front = [%d]\n", extents_occupied_by_headers_at_front); |
| 364 | ecryptfs_printk(KERN_DEBUG, " * lower_extent_num = [0x%.16x]\n", |
| 365 | lower_extent_num); |
| 366 | ecryptfs_printk(KERN_DEBUG, " * extents_per_page = [%d]\n", |
| 367 | extents_per_page); |
| 368 | ecryptfs_printk(KERN_DEBUG, " * (*lower_page_idx) = [0x%.16x]\n", |
| 369 | (*lower_page_idx)); |
| 370 | ecryptfs_printk(KERN_DEBUG, " * extent_offset = [%d]\n", |
| 371 | extent_offset); |
| 372 | ecryptfs_printk(KERN_DEBUG, " * (*byte_offset) = [%d]\n", |
| 373 | (*byte_offset)); |
| 374 | } |
| 375 | |
| 376 | static int ecryptfs_write_out_page(struct ecryptfs_page_crypt_context *ctx, |
| 377 | struct page *lower_page, |
| 378 | struct inode *lower_inode, |
| 379 | int byte_offset_in_page, int bytes_to_write) |
| 380 | { |
| 381 | int rc = 0; |
| 382 | |
| 383 | if (ctx->mode == ECRYPTFS_PREPARE_COMMIT_MODE) { |
| 384 | rc = ecryptfs_commit_lower_page(lower_page, lower_inode, |
| 385 | ctx->param.lower_file, |
| 386 | byte_offset_in_page, |
| 387 | bytes_to_write); |
| 388 | if (rc) { |
| 389 | ecryptfs_printk(KERN_ERR, "Error calling lower " |
| 390 | "commit; rc = [%d]\n", rc); |
| 391 | goto out; |
| 392 | } |
| 393 | } else { |
| 394 | rc = ecryptfs_writepage_and_release_lower_page(lower_page, |
| 395 | lower_inode, |
| 396 | ctx->param.wbc); |
| 397 | if (rc) { |
| 398 | ecryptfs_printk(KERN_ERR, "Error calling lower " |
| 399 | "writepage(); rc = [%d]\n", rc); |
| 400 | goto out; |
| 401 | } |
| 402 | } |
| 403 | out: |
| 404 | return rc; |
| 405 | } |
| 406 | |
| 407 | static int ecryptfs_read_in_page(struct ecryptfs_page_crypt_context *ctx, |
| 408 | struct page **lower_page, |
| 409 | struct inode *lower_inode, |
| 410 | unsigned long lower_page_idx, |
| 411 | int byte_offset_in_page) |
| 412 | { |
| 413 | int rc = 0; |
| 414 | |
| 415 | if (ctx->mode == ECRYPTFS_PREPARE_COMMIT_MODE) { |
| 416 | /* TODO: Limit this to only the data extents that are |
| 417 | * needed */ |
| 418 | rc = ecryptfs_get_lower_page(lower_page, lower_inode, |
| 419 | ctx->param.lower_file, |
| 420 | lower_page_idx, |
| 421 | byte_offset_in_page, |
| 422 | (PAGE_CACHE_SIZE |
| 423 | - byte_offset_in_page)); |
| 424 | if (rc) { |
| 425 | ecryptfs_printk( |
| 426 | KERN_ERR, "Error attempting to grab, map, " |
| 427 | "and prepare_write lower page with index " |
| 428 | "[0x%.16x]; rc = [%d]\n", lower_page_idx, rc); |
| 429 | goto out; |
| 430 | } |
| 431 | } else { |
| 432 | rc = ecryptfs_grab_and_map_lower_page(lower_page, NULL, |
| 433 | lower_inode, |
| 434 | lower_page_idx); |
| 435 | if (rc) { |
| 436 | ecryptfs_printk( |
| 437 | KERN_ERR, "Error attempting to grab and map " |
| 438 | "lower page with index [0x%.16x]; rc = [%d]\n", |
| 439 | lower_page_idx, rc); |
| 440 | goto out; |
| 441 | } |
| 442 | } |
| 443 | out: |
| 444 | return rc; |
| 445 | } |
| 446 | |
| 447 | /** |
| 448 | * ecryptfs_encrypt_page |
| 449 | * @ctx: The context of the page |
| 450 | * |
| 451 | * Encrypt an eCryptfs page. This is done on a per-extent basis. Note |
| 452 | * that eCryptfs pages may straddle the lower pages -- for instance, |
| 453 | * if the file was created on a machine with an 8K page size |
| 454 | * (resulting in an 8K header), and then the file is copied onto a |
| 455 | * host with a 32K page size, then when reading page 0 of the eCryptfs |
| 456 | * file, 24K of page 0 of the lower file will be read and decrypted, |
| 457 | * and then 8K of page 1 of the lower file will be read and decrypted. |
| 458 | * |
| 459 | * The actual operations performed on each page depends on the |
| 460 | * contents of the ecryptfs_page_crypt_context struct. |
| 461 | * |
| 462 | * Returns zero on success; negative on error |
| 463 | */ |
| 464 | int ecryptfs_encrypt_page(struct ecryptfs_page_crypt_context *ctx) |
| 465 | { |
| 466 | char extent_iv[ECRYPTFS_MAX_IV_BYTES]; |
| 467 | unsigned long base_extent; |
| 468 | unsigned long extent_offset = 0; |
| 469 | unsigned long lower_page_idx = 0; |
| 470 | unsigned long prior_lower_page_idx = 0; |
| 471 | struct page *lower_page; |
| 472 | struct inode *lower_inode; |
| 473 | struct ecryptfs_inode_info *inode_info; |
| 474 | struct ecryptfs_crypt_stat *crypt_stat; |
| 475 | int rc = 0; |
| 476 | int lower_byte_offset = 0; |
| 477 | int orig_byte_offset = 0; |
| 478 | int num_extents_per_page; |
| 479 | #define ECRYPTFS_PAGE_STATE_UNREAD 0 |
| 480 | #define ECRYPTFS_PAGE_STATE_READ 1 |
| 481 | #define ECRYPTFS_PAGE_STATE_MODIFIED 2 |
| 482 | #define ECRYPTFS_PAGE_STATE_WRITTEN 3 |
| 483 | int page_state; |
| 484 | |
| 485 | lower_inode = ecryptfs_inode_to_lower(ctx->page->mapping->host); |
| 486 | inode_info = ecryptfs_inode_to_private(ctx->page->mapping->host); |
| 487 | crypt_stat = &inode_info->crypt_stat; |
| 488 | if (!ECRYPTFS_CHECK_FLAG(crypt_stat->flags, ECRYPTFS_ENCRYPTED)) { |
| 489 | rc = ecryptfs_copy_page_to_lower(ctx->page, lower_inode, |
| 490 | ctx->param.lower_file); |
| 491 | if (rc) |
| 492 | ecryptfs_printk(KERN_ERR, "Error attempting to copy " |
| 493 | "page at index [0x%.16x]\n", |
| 494 | ctx->page->index); |
| 495 | goto out; |
| 496 | } |
| 497 | num_extents_per_page = PAGE_CACHE_SIZE / crypt_stat->extent_size; |
| 498 | base_extent = (ctx->page->index * num_extents_per_page); |
| 499 | page_state = ECRYPTFS_PAGE_STATE_UNREAD; |
| 500 | while (extent_offset < num_extents_per_page) { |
| 501 | ecryptfs_extent_to_lwr_pg_idx_and_offset( |
| 502 | &lower_page_idx, &lower_byte_offset, crypt_stat, |
| 503 | (base_extent + extent_offset)); |
| 504 | if (prior_lower_page_idx != lower_page_idx |
| 505 | && page_state == ECRYPTFS_PAGE_STATE_MODIFIED) { |
| 506 | rc = ecryptfs_write_out_page(ctx, lower_page, |
| 507 | lower_inode, |
| 508 | orig_byte_offset, |
| 509 | (PAGE_CACHE_SIZE |
| 510 | - orig_byte_offset)); |
| 511 | if (rc) { |
| 512 | ecryptfs_printk(KERN_ERR, "Error attempting " |
| 513 | "to write out page; rc = [%d]" |
| 514 | "\n", rc); |
| 515 | goto out; |
| 516 | } |
| 517 | page_state = ECRYPTFS_PAGE_STATE_WRITTEN; |
| 518 | } |
| 519 | if (page_state == ECRYPTFS_PAGE_STATE_UNREAD |
| 520 | || page_state == ECRYPTFS_PAGE_STATE_WRITTEN) { |
| 521 | rc = ecryptfs_read_in_page(ctx, &lower_page, |
| 522 | lower_inode, lower_page_idx, |
| 523 | lower_byte_offset); |
| 524 | if (rc) { |
| 525 | ecryptfs_printk(KERN_ERR, "Error attempting " |
| 526 | "to read in lower page with " |
| 527 | "index [0x%.16x]; rc = [%d]\n", |
| 528 | lower_page_idx, rc); |
| 529 | goto out; |
| 530 | } |
| 531 | orig_byte_offset = lower_byte_offset; |
| 532 | prior_lower_page_idx = lower_page_idx; |
| 533 | page_state = ECRYPTFS_PAGE_STATE_READ; |
| 534 | } |
| 535 | BUG_ON(!(page_state == ECRYPTFS_PAGE_STATE_MODIFIED |
| 536 | || page_state == ECRYPTFS_PAGE_STATE_READ)); |
| 537 | rc = ecryptfs_derive_iv(extent_iv, crypt_stat, |
| 538 | (base_extent + extent_offset)); |
| 539 | if (rc) { |
| 540 | ecryptfs_printk(KERN_ERR, "Error attempting to " |
| 541 | "derive IV for extent [0x%.16x]; " |
| 542 | "rc = [%d]\n", |
| 543 | (base_extent + extent_offset), rc); |
| 544 | goto out; |
| 545 | } |
| 546 | if (unlikely(ecryptfs_verbosity > 0)) { |
| 547 | ecryptfs_printk(KERN_DEBUG, "Encrypting extent " |
| 548 | "with iv:\n"); |
| 549 | ecryptfs_dump_hex(extent_iv, crypt_stat->iv_bytes); |
| 550 | ecryptfs_printk(KERN_DEBUG, "First 8 bytes before " |
| 551 | "encryption:\n"); |
| 552 | ecryptfs_dump_hex((char *) |
| 553 | (page_address(ctx->page) |
| 554 | + (extent_offset |
| 555 | * crypt_stat->extent_size)), 8); |
| 556 | } |
| 557 | rc = ecryptfs_encrypt_page_offset( |
| 558 | crypt_stat, lower_page, lower_byte_offset, ctx->page, |
| 559 | (extent_offset * crypt_stat->extent_size), |
| 560 | crypt_stat->extent_size, extent_iv); |
| 561 | ecryptfs_printk(KERN_DEBUG, "Encrypt extent [0x%.16x]; " |
| 562 | "rc = [%d]\n", |
| 563 | (base_extent + extent_offset), rc); |
| 564 | if (unlikely(ecryptfs_verbosity > 0)) { |
| 565 | ecryptfs_printk(KERN_DEBUG, "First 8 bytes after " |
| 566 | "encryption:\n"); |
| 567 | ecryptfs_dump_hex((char *)(page_address(lower_page) |
| 568 | + lower_byte_offset), 8); |
| 569 | } |
| 570 | page_state = ECRYPTFS_PAGE_STATE_MODIFIED; |
| 571 | extent_offset++; |
| 572 | } |
| 573 | BUG_ON(orig_byte_offset != 0); |
| 574 | rc = ecryptfs_write_out_page(ctx, lower_page, lower_inode, 0, |
| 575 | (lower_byte_offset |
| 576 | + crypt_stat->extent_size)); |
| 577 | if (rc) { |
| 578 | ecryptfs_printk(KERN_ERR, "Error attempting to write out " |
| 579 | "page; rc = [%d]\n", rc); |
| 580 | goto out; |
| 581 | } |
| 582 | out: |
| 583 | return rc; |
| 584 | } |
| 585 | |
| 586 | /** |
| 587 | * ecryptfs_decrypt_page |
| 588 | * @file: The ecryptfs file |
| 589 | * @page: The page in ecryptfs to decrypt |
| 590 | * |
| 591 | * Decrypt an eCryptfs page. This is done on a per-extent basis. Note |
| 592 | * that eCryptfs pages may straddle the lower pages -- for instance, |
| 593 | * if the file was created on a machine with an 8K page size |
| 594 | * (resulting in an 8K header), and then the file is copied onto a |
| 595 | * host with a 32K page size, then when reading page 0 of the eCryptfs |
| 596 | * file, 24K of page 0 of the lower file will be read and decrypted, |
| 597 | * and then 8K of page 1 of the lower file will be read and decrypted. |
| 598 | * |
| 599 | * Returns zero on success; negative on error |
| 600 | */ |
| 601 | int ecryptfs_decrypt_page(struct file *file, struct page *page) |
| 602 | { |
| 603 | char extent_iv[ECRYPTFS_MAX_IV_BYTES]; |
| 604 | unsigned long base_extent; |
| 605 | unsigned long extent_offset = 0; |
| 606 | unsigned long lower_page_idx = 0; |
| 607 | unsigned long prior_lower_page_idx = 0; |
| 608 | struct page *lower_page; |
| 609 | char *lower_page_virt = NULL; |
| 610 | struct inode *lower_inode; |
| 611 | struct ecryptfs_crypt_stat *crypt_stat; |
| 612 | int rc = 0; |
| 613 | int byte_offset; |
| 614 | int num_extents_per_page; |
| 615 | int page_state; |
| 616 | |
| 617 | crypt_stat = &(ecryptfs_inode_to_private( |
| 618 | page->mapping->host)->crypt_stat); |
| 619 | lower_inode = ecryptfs_inode_to_lower(page->mapping->host); |
| 620 | if (!ECRYPTFS_CHECK_FLAG(crypt_stat->flags, ECRYPTFS_ENCRYPTED)) { |
| 621 | rc = ecryptfs_do_readpage(file, page, page->index); |
| 622 | if (rc) |
| 623 | ecryptfs_printk(KERN_ERR, "Error attempting to copy " |
| 624 | "page at index [0x%.16x]\n", |
| 625 | page->index); |
| 626 | goto out; |
| 627 | } |
| 628 | num_extents_per_page = PAGE_CACHE_SIZE / crypt_stat->extent_size; |
| 629 | base_extent = (page->index * num_extents_per_page); |
| 630 | lower_page_virt = kmem_cache_alloc(ecryptfs_lower_page_cache, |
Christoph Lameter | e94b176 | 2006-12-06 20:33:17 -0800 | [diff] [blame] | 631 | GFP_KERNEL); |
Michael Halcrow | 237fead | 2006-10-04 02:16:22 -0700 | [diff] [blame] | 632 | if (!lower_page_virt) { |
| 633 | rc = -ENOMEM; |
| 634 | ecryptfs_printk(KERN_ERR, "Error getting page for encrypted " |
| 635 | "lower page(s)\n"); |
| 636 | goto out; |
| 637 | } |
| 638 | lower_page = virt_to_page(lower_page_virt); |
| 639 | page_state = ECRYPTFS_PAGE_STATE_UNREAD; |
| 640 | while (extent_offset < num_extents_per_page) { |
| 641 | ecryptfs_extent_to_lwr_pg_idx_and_offset( |
| 642 | &lower_page_idx, &byte_offset, crypt_stat, |
| 643 | (base_extent + extent_offset)); |
| 644 | if (prior_lower_page_idx != lower_page_idx |
| 645 | || page_state == ECRYPTFS_PAGE_STATE_UNREAD) { |
| 646 | rc = ecryptfs_do_readpage(file, lower_page, |
| 647 | lower_page_idx); |
| 648 | if (rc) { |
| 649 | ecryptfs_printk(KERN_ERR, "Error reading " |
| 650 | "lower encrypted page; rc = " |
| 651 | "[%d]\n", rc); |
| 652 | goto out; |
| 653 | } |
| 654 | prior_lower_page_idx = lower_page_idx; |
| 655 | page_state = ECRYPTFS_PAGE_STATE_READ; |
| 656 | } |
| 657 | rc = ecryptfs_derive_iv(extent_iv, crypt_stat, |
| 658 | (base_extent + extent_offset)); |
| 659 | if (rc) { |
| 660 | ecryptfs_printk(KERN_ERR, "Error attempting to " |
| 661 | "derive IV for extent [0x%.16x]; rc = " |
| 662 | "[%d]\n", |
| 663 | (base_extent + extent_offset), rc); |
| 664 | goto out; |
| 665 | } |
| 666 | if (unlikely(ecryptfs_verbosity > 0)) { |
| 667 | ecryptfs_printk(KERN_DEBUG, "Decrypting extent " |
| 668 | "with iv:\n"); |
| 669 | ecryptfs_dump_hex(extent_iv, crypt_stat->iv_bytes); |
| 670 | ecryptfs_printk(KERN_DEBUG, "First 8 bytes before " |
| 671 | "decryption:\n"); |
| 672 | ecryptfs_dump_hex((lower_page_virt + byte_offset), 8); |
| 673 | } |
| 674 | rc = ecryptfs_decrypt_page_offset(crypt_stat, page, |
| 675 | (extent_offset |
| 676 | * crypt_stat->extent_size), |
| 677 | lower_page, byte_offset, |
| 678 | crypt_stat->extent_size, |
| 679 | extent_iv); |
| 680 | if (rc != crypt_stat->extent_size) { |
| 681 | ecryptfs_printk(KERN_ERR, "Error attempting to " |
| 682 | "decrypt extent [0x%.16x]\n", |
| 683 | (base_extent + extent_offset)); |
| 684 | goto out; |
| 685 | } |
| 686 | rc = 0; |
| 687 | if (unlikely(ecryptfs_verbosity > 0)) { |
| 688 | ecryptfs_printk(KERN_DEBUG, "First 8 bytes after " |
| 689 | "decryption:\n"); |
| 690 | ecryptfs_dump_hex((char *)(page_address(page) |
| 691 | + byte_offset), 8); |
| 692 | } |
| 693 | extent_offset++; |
| 694 | } |
| 695 | out: |
| 696 | if (lower_page_virt) |
| 697 | kmem_cache_free(ecryptfs_lower_page_cache, lower_page_virt); |
| 698 | return rc; |
| 699 | } |
| 700 | |
| 701 | /** |
| 702 | * decrypt_scatterlist |
| 703 | * |
| 704 | * Returns the number of bytes decrypted; negative value on error |
| 705 | */ |
| 706 | static int decrypt_scatterlist(struct ecryptfs_crypt_stat *crypt_stat, |
| 707 | struct scatterlist *dest_sg, |
| 708 | struct scatterlist *src_sg, int size, |
| 709 | unsigned char *iv) |
| 710 | { |
Michael Halcrow | 8bba066 | 2006-10-30 22:07:18 -0800 | [diff] [blame] | 711 | struct blkcipher_desc desc = { |
| 712 | .tfm = crypt_stat->tfm, |
| 713 | .info = iv, |
| 714 | .flags = CRYPTO_TFM_REQ_MAY_SLEEP |
| 715 | }; |
Michael Halcrow | 237fead | 2006-10-04 02:16:22 -0700 | [diff] [blame] | 716 | int rc = 0; |
| 717 | |
| 718 | /* Consider doing this once, when the file is opened */ |
| 719 | mutex_lock(&crypt_stat->cs_tfm_mutex); |
Michael Halcrow | 8bba066 | 2006-10-30 22:07:18 -0800 | [diff] [blame] | 720 | rc = crypto_blkcipher_setkey(crypt_stat->tfm, crypt_stat->key, |
| 721 | crypt_stat->key_size); |
Michael Halcrow | 237fead | 2006-10-04 02:16:22 -0700 | [diff] [blame] | 722 | if (rc) { |
| 723 | ecryptfs_printk(KERN_ERR, "Error setting key; rc = [%d]\n", |
| 724 | rc); |
| 725 | mutex_unlock(&crypt_stat->cs_tfm_mutex); |
| 726 | rc = -EINVAL; |
| 727 | goto out; |
| 728 | } |
| 729 | ecryptfs_printk(KERN_DEBUG, "Decrypting [%d] bytes.\n", size); |
Michael Halcrow | 8bba066 | 2006-10-30 22:07:18 -0800 | [diff] [blame] | 730 | rc = crypto_blkcipher_decrypt_iv(&desc, dest_sg, src_sg, size); |
Michael Halcrow | 237fead | 2006-10-04 02:16:22 -0700 | [diff] [blame] | 731 | mutex_unlock(&crypt_stat->cs_tfm_mutex); |
| 732 | if (rc) { |
| 733 | ecryptfs_printk(KERN_ERR, "Error decrypting; rc = [%d]\n", |
| 734 | rc); |
| 735 | goto out; |
| 736 | } |
| 737 | rc = size; |
| 738 | out: |
| 739 | return rc; |
| 740 | } |
| 741 | |
| 742 | /** |
| 743 | * ecryptfs_encrypt_page_offset |
| 744 | * |
| 745 | * Returns the number of bytes encrypted |
| 746 | */ |
| 747 | static int |
| 748 | ecryptfs_encrypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat, |
| 749 | struct page *dst_page, int dst_offset, |
| 750 | struct page *src_page, int src_offset, int size, |
| 751 | unsigned char *iv) |
| 752 | { |
| 753 | struct scatterlist src_sg, dst_sg; |
| 754 | |
| 755 | src_sg.page = src_page; |
| 756 | src_sg.offset = src_offset; |
| 757 | src_sg.length = size; |
| 758 | dst_sg.page = dst_page; |
| 759 | dst_sg.offset = dst_offset; |
| 760 | dst_sg.length = size; |
| 761 | return encrypt_scatterlist(crypt_stat, &dst_sg, &src_sg, size, iv); |
| 762 | } |
| 763 | |
| 764 | /** |
| 765 | * ecryptfs_decrypt_page_offset |
| 766 | * |
| 767 | * Returns the number of bytes decrypted |
| 768 | */ |
| 769 | static int |
| 770 | ecryptfs_decrypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat, |
| 771 | struct page *dst_page, int dst_offset, |
| 772 | struct page *src_page, int src_offset, int size, |
| 773 | unsigned char *iv) |
| 774 | { |
| 775 | struct scatterlist src_sg, dst_sg; |
| 776 | |
| 777 | src_sg.page = src_page; |
| 778 | src_sg.offset = src_offset; |
| 779 | src_sg.length = size; |
| 780 | dst_sg.page = dst_page; |
| 781 | dst_sg.offset = dst_offset; |
| 782 | dst_sg.length = size; |
| 783 | return decrypt_scatterlist(crypt_stat, &dst_sg, &src_sg, size, iv); |
| 784 | } |
| 785 | |
| 786 | #define ECRYPTFS_MAX_SCATTERLIST_LEN 4 |
| 787 | |
| 788 | /** |
| 789 | * ecryptfs_init_crypt_ctx |
| 790 | * @crypt_stat: Uninitilized crypt stats structure |
| 791 | * |
| 792 | * Initialize the crypto context. |
| 793 | * |
| 794 | * TODO: Performance: Keep a cache of initialized cipher contexts; |
| 795 | * only init if needed |
| 796 | */ |
| 797 | int ecryptfs_init_crypt_ctx(struct ecryptfs_crypt_stat *crypt_stat) |
| 798 | { |
Michael Halcrow | 8bba066 | 2006-10-30 22:07:18 -0800 | [diff] [blame] | 799 | char *full_alg_name; |
Michael Halcrow | 237fead | 2006-10-04 02:16:22 -0700 | [diff] [blame] | 800 | int rc = -EINVAL; |
| 801 | |
| 802 | if (!crypt_stat->cipher) { |
| 803 | ecryptfs_printk(KERN_ERR, "No cipher specified\n"); |
| 804 | goto out; |
| 805 | } |
| 806 | ecryptfs_printk(KERN_DEBUG, |
| 807 | "Initializing cipher [%s]; strlen = [%d]; " |
| 808 | "key_size_bits = [%d]\n", |
| 809 | crypt_stat->cipher, (int)strlen(crypt_stat->cipher), |
| 810 | crypt_stat->key_size << 3); |
| 811 | if (crypt_stat->tfm) { |
| 812 | rc = 0; |
| 813 | goto out; |
| 814 | } |
| 815 | mutex_lock(&crypt_stat->cs_tfm_mutex); |
Michael Halcrow | 8bba066 | 2006-10-30 22:07:18 -0800 | [diff] [blame] | 816 | rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name, |
| 817 | crypt_stat->cipher, "cbc"); |
| 818 | if (rc) |
| 819 | goto out; |
| 820 | crypt_stat->tfm = crypto_alloc_blkcipher(full_alg_name, 0, |
| 821 | CRYPTO_ALG_ASYNC); |
| 822 | kfree(full_alg_name); |
Akinobu Mita | de88777 | 2006-11-28 12:29:49 -0800 | [diff] [blame] | 823 | if (IS_ERR(crypt_stat->tfm)) { |
| 824 | rc = PTR_ERR(crypt_stat->tfm); |
Michael Halcrow | 237fead | 2006-10-04 02:16:22 -0700 | [diff] [blame] | 825 | ecryptfs_printk(KERN_ERR, "cryptfs: init_crypt_ctx(): " |
| 826 | "Error initializing cipher [%s]\n", |
| 827 | crypt_stat->cipher); |
Michael Halcrow | 8bba066 | 2006-10-30 22:07:18 -0800 | [diff] [blame] | 828 | mutex_unlock(&crypt_stat->cs_tfm_mutex); |
Michael Halcrow | 237fead | 2006-10-04 02:16:22 -0700 | [diff] [blame] | 829 | goto out; |
| 830 | } |
Michael Halcrow | 8bba066 | 2006-10-30 22:07:18 -0800 | [diff] [blame] | 831 | crypto_blkcipher_set_flags(crypt_stat->tfm, |
| 832 | (ECRYPTFS_DEFAULT_CHAINING_MODE |
| 833 | | CRYPTO_TFM_REQ_WEAK_KEY)); |
| 834 | mutex_unlock(&crypt_stat->cs_tfm_mutex); |
Michael Halcrow | 237fead | 2006-10-04 02:16:22 -0700 | [diff] [blame] | 835 | rc = 0; |
| 836 | out: |
| 837 | return rc; |
| 838 | } |
| 839 | |
| 840 | static void set_extent_mask_and_shift(struct ecryptfs_crypt_stat *crypt_stat) |
| 841 | { |
| 842 | int extent_size_tmp; |
| 843 | |
| 844 | crypt_stat->extent_mask = 0xFFFFFFFF; |
| 845 | crypt_stat->extent_shift = 0; |
| 846 | if (crypt_stat->extent_size == 0) |
| 847 | return; |
| 848 | extent_size_tmp = crypt_stat->extent_size; |
| 849 | while ((extent_size_tmp & 0x01) == 0) { |
| 850 | extent_size_tmp >>= 1; |
| 851 | crypt_stat->extent_mask <<= 1; |
| 852 | crypt_stat->extent_shift++; |
| 853 | } |
| 854 | } |
| 855 | |
| 856 | void ecryptfs_set_default_sizes(struct ecryptfs_crypt_stat *crypt_stat) |
| 857 | { |
| 858 | /* Default values; may be overwritten as we are parsing the |
| 859 | * packets. */ |
| 860 | crypt_stat->extent_size = ECRYPTFS_DEFAULT_EXTENT_SIZE; |
| 861 | set_extent_mask_and_shift(crypt_stat); |
| 862 | crypt_stat->iv_bytes = ECRYPTFS_DEFAULT_IV_BYTES; |
| 863 | if (PAGE_CACHE_SIZE <= ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE) { |
| 864 | crypt_stat->header_extent_size = |
| 865 | ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE; |
| 866 | } else |
| 867 | crypt_stat->header_extent_size = PAGE_CACHE_SIZE; |
| 868 | crypt_stat->num_header_extents_at_front = 1; |
| 869 | } |
| 870 | |
| 871 | /** |
| 872 | * ecryptfs_compute_root_iv |
| 873 | * @crypt_stats |
| 874 | * |
| 875 | * On error, sets the root IV to all 0's. |
| 876 | */ |
| 877 | int ecryptfs_compute_root_iv(struct ecryptfs_crypt_stat *crypt_stat) |
| 878 | { |
| 879 | int rc = 0; |
| 880 | char dst[MD5_DIGEST_SIZE]; |
| 881 | |
| 882 | BUG_ON(crypt_stat->iv_bytes > MD5_DIGEST_SIZE); |
| 883 | BUG_ON(crypt_stat->iv_bytes <= 0); |
| 884 | if (!ECRYPTFS_CHECK_FLAG(crypt_stat->flags, ECRYPTFS_KEY_VALID)) { |
| 885 | rc = -EINVAL; |
| 886 | ecryptfs_printk(KERN_WARNING, "Session key not valid; " |
| 887 | "cannot generate root IV\n"); |
| 888 | goto out; |
| 889 | } |
| 890 | rc = ecryptfs_calculate_md5(dst, crypt_stat, crypt_stat->key, |
| 891 | crypt_stat->key_size); |
| 892 | if (rc) { |
| 893 | ecryptfs_printk(KERN_WARNING, "Error attempting to compute " |
| 894 | "MD5 while generating root IV\n"); |
| 895 | goto out; |
| 896 | } |
| 897 | memcpy(crypt_stat->root_iv, dst, crypt_stat->iv_bytes); |
| 898 | out: |
| 899 | if (rc) { |
| 900 | memset(crypt_stat->root_iv, 0, crypt_stat->iv_bytes); |
| 901 | ECRYPTFS_SET_FLAG(crypt_stat->flags, |
| 902 | ECRYPTFS_SECURITY_WARNING); |
| 903 | } |
| 904 | return rc; |
| 905 | } |
| 906 | |
| 907 | static void ecryptfs_generate_new_key(struct ecryptfs_crypt_stat *crypt_stat) |
| 908 | { |
| 909 | get_random_bytes(crypt_stat->key, crypt_stat->key_size); |
| 910 | ECRYPTFS_SET_FLAG(crypt_stat->flags, ECRYPTFS_KEY_VALID); |
| 911 | ecryptfs_compute_root_iv(crypt_stat); |
| 912 | if (unlikely(ecryptfs_verbosity > 0)) { |
| 913 | ecryptfs_printk(KERN_DEBUG, "Generated new session key:\n"); |
| 914 | ecryptfs_dump_hex(crypt_stat->key, |
| 915 | crypt_stat->key_size); |
| 916 | } |
| 917 | } |
| 918 | |
| 919 | /** |
| 920 | * ecryptfs_set_default_crypt_stat_vals |
| 921 | * @crypt_stat |
| 922 | * |
| 923 | * Default values in the event that policy does not override them. |
| 924 | */ |
| 925 | static void ecryptfs_set_default_crypt_stat_vals( |
| 926 | struct ecryptfs_crypt_stat *crypt_stat, |
| 927 | struct ecryptfs_mount_crypt_stat *mount_crypt_stat) |
| 928 | { |
| 929 | ecryptfs_set_default_sizes(crypt_stat); |
| 930 | strcpy(crypt_stat->cipher, ECRYPTFS_DEFAULT_CIPHER); |
| 931 | crypt_stat->key_size = ECRYPTFS_DEFAULT_KEY_BYTES; |
| 932 | ECRYPTFS_CLEAR_FLAG(crypt_stat->flags, ECRYPTFS_KEY_VALID); |
| 933 | crypt_stat->file_version = ECRYPTFS_FILE_VERSION; |
| 934 | crypt_stat->mount_crypt_stat = mount_crypt_stat; |
| 935 | } |
| 936 | |
| 937 | /** |
| 938 | * ecryptfs_new_file_context |
| 939 | * @ecryptfs_dentry |
| 940 | * |
| 941 | * If the crypto context for the file has not yet been established, |
| 942 | * this is where we do that. Establishing a new crypto context |
| 943 | * involves the following decisions: |
| 944 | * - What cipher to use? |
| 945 | * - What set of authentication tokens to use? |
| 946 | * Here we just worry about getting enough information into the |
| 947 | * authentication tokens so that we know that they are available. |
| 948 | * We associate the available authentication tokens with the new file |
| 949 | * via the set of signatures in the crypt_stat struct. Later, when |
| 950 | * the headers are actually written out, we may again defer to |
| 951 | * userspace to perform the encryption of the session key; for the |
| 952 | * foreseeable future, this will be the case with public key packets. |
| 953 | * |
| 954 | * Returns zero on success; non-zero otherwise |
| 955 | */ |
| 956 | /* Associate an authentication token(s) with the file */ |
| 957 | int ecryptfs_new_file_context(struct dentry *ecryptfs_dentry) |
| 958 | { |
| 959 | int rc = 0; |
| 960 | struct ecryptfs_crypt_stat *crypt_stat = |
| 961 | &ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat; |
| 962 | struct ecryptfs_mount_crypt_stat *mount_crypt_stat = |
| 963 | &ecryptfs_superblock_to_private( |
| 964 | ecryptfs_dentry->d_sb)->mount_crypt_stat; |
| 965 | int cipher_name_len; |
| 966 | |
| 967 | ecryptfs_set_default_crypt_stat_vals(crypt_stat, mount_crypt_stat); |
| 968 | /* See if there are mount crypt options */ |
| 969 | if (mount_crypt_stat->global_auth_tok) { |
| 970 | ecryptfs_printk(KERN_DEBUG, "Initializing context for new " |
| 971 | "file using mount_crypt_stat\n"); |
| 972 | ECRYPTFS_SET_FLAG(crypt_stat->flags, ECRYPTFS_ENCRYPTED); |
| 973 | ECRYPTFS_SET_FLAG(crypt_stat->flags, ECRYPTFS_KEY_VALID); |
| 974 | memcpy(crypt_stat->keysigs[crypt_stat->num_keysigs++], |
| 975 | mount_crypt_stat->global_auth_tok_sig, |
| 976 | ECRYPTFS_SIG_SIZE_HEX); |
| 977 | cipher_name_len = |
| 978 | strlen(mount_crypt_stat->global_default_cipher_name); |
| 979 | memcpy(crypt_stat->cipher, |
| 980 | mount_crypt_stat->global_default_cipher_name, |
| 981 | cipher_name_len); |
| 982 | crypt_stat->cipher[cipher_name_len] = '\0'; |
| 983 | crypt_stat->key_size = |
| 984 | mount_crypt_stat->global_default_cipher_key_size; |
| 985 | ecryptfs_generate_new_key(crypt_stat); |
| 986 | } else |
| 987 | /* We should not encounter this scenario since we |
| 988 | * should detect lack of global_auth_tok at mount time |
| 989 | * TODO: Applies to 0.1 release only; remove in future |
| 990 | * release */ |
| 991 | BUG(); |
| 992 | rc = ecryptfs_init_crypt_ctx(crypt_stat); |
| 993 | if (rc) |
| 994 | ecryptfs_printk(KERN_ERR, "Error initializing cryptographic " |
| 995 | "context for cipher [%s]: rc = [%d]\n", |
| 996 | crypt_stat->cipher, rc); |
| 997 | return rc; |
| 998 | } |
| 999 | |
| 1000 | /** |
| 1001 | * contains_ecryptfs_marker - check for the ecryptfs marker |
| 1002 | * @data: The data block in which to check |
| 1003 | * |
| 1004 | * Returns one if marker found; zero if not found |
| 1005 | */ |
| 1006 | int contains_ecryptfs_marker(char *data) |
| 1007 | { |
| 1008 | u32 m_1, m_2; |
| 1009 | |
| 1010 | memcpy(&m_1, data, 4); |
| 1011 | m_1 = be32_to_cpu(m_1); |
| 1012 | memcpy(&m_2, (data + 4), 4); |
| 1013 | m_2 = be32_to_cpu(m_2); |
| 1014 | if ((m_1 ^ MAGIC_ECRYPTFS_MARKER) == m_2) |
| 1015 | return 1; |
| 1016 | ecryptfs_printk(KERN_DEBUG, "m_1 = [0x%.8x]; m_2 = [0x%.8x]; " |
| 1017 | "MAGIC_ECRYPTFS_MARKER = [0x%.8x]\n", m_1, m_2, |
| 1018 | MAGIC_ECRYPTFS_MARKER); |
| 1019 | ecryptfs_printk(KERN_DEBUG, "(m_1 ^ MAGIC_ECRYPTFS_MARKER) = " |
| 1020 | "[0x%.8x]\n", (m_1 ^ MAGIC_ECRYPTFS_MARKER)); |
| 1021 | return 0; |
| 1022 | } |
| 1023 | |
| 1024 | struct ecryptfs_flag_map_elem { |
| 1025 | u32 file_flag; |
| 1026 | u32 local_flag; |
| 1027 | }; |
| 1028 | |
| 1029 | /* Add support for additional flags by adding elements here. */ |
| 1030 | static struct ecryptfs_flag_map_elem ecryptfs_flag_map[] = { |
| 1031 | {0x00000001, ECRYPTFS_ENABLE_HMAC}, |
| 1032 | {0x00000002, ECRYPTFS_ENCRYPTED} |
| 1033 | }; |
| 1034 | |
| 1035 | /** |
| 1036 | * ecryptfs_process_flags |
| 1037 | * @crypt_stat |
| 1038 | * @page_virt: Source data to be parsed |
| 1039 | * @bytes_read: Updated with the number of bytes read |
| 1040 | * |
| 1041 | * Returns zero on success; non-zero if the flag set is invalid |
| 1042 | */ |
| 1043 | static int ecryptfs_process_flags(struct ecryptfs_crypt_stat *crypt_stat, |
| 1044 | char *page_virt, int *bytes_read) |
| 1045 | { |
| 1046 | int rc = 0; |
| 1047 | int i; |
| 1048 | u32 flags; |
| 1049 | |
| 1050 | memcpy(&flags, page_virt, 4); |
| 1051 | flags = be32_to_cpu(flags); |
| 1052 | for (i = 0; i < ((sizeof(ecryptfs_flag_map) |
| 1053 | / sizeof(struct ecryptfs_flag_map_elem))); i++) |
| 1054 | if (flags & ecryptfs_flag_map[i].file_flag) { |
| 1055 | ECRYPTFS_SET_FLAG(crypt_stat->flags, |
| 1056 | ecryptfs_flag_map[i].local_flag); |
| 1057 | } else |
| 1058 | ECRYPTFS_CLEAR_FLAG(crypt_stat->flags, |
| 1059 | ecryptfs_flag_map[i].local_flag); |
| 1060 | /* Version is in top 8 bits of the 32-bit flag vector */ |
| 1061 | crypt_stat->file_version = ((flags >> 24) & 0xFF); |
| 1062 | (*bytes_read) = 4; |
| 1063 | return rc; |
| 1064 | } |
| 1065 | |
| 1066 | /** |
| 1067 | * write_ecryptfs_marker |
| 1068 | * @page_virt: The pointer to in a page to begin writing the marker |
| 1069 | * @written: Number of bytes written |
| 1070 | * |
| 1071 | * Marker = 0x3c81b7f5 |
| 1072 | */ |
| 1073 | static void write_ecryptfs_marker(char *page_virt, size_t *written) |
| 1074 | { |
| 1075 | u32 m_1, m_2; |
| 1076 | |
| 1077 | get_random_bytes(&m_1, (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2)); |
| 1078 | m_2 = (m_1 ^ MAGIC_ECRYPTFS_MARKER); |
| 1079 | m_1 = cpu_to_be32(m_1); |
| 1080 | memcpy(page_virt, &m_1, (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2)); |
| 1081 | m_2 = cpu_to_be32(m_2); |
| 1082 | memcpy(page_virt + (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2), &m_2, |
| 1083 | (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2)); |
| 1084 | (*written) = MAGIC_ECRYPTFS_MARKER_SIZE_BYTES; |
| 1085 | } |
| 1086 | |
| 1087 | static void |
| 1088 | write_ecryptfs_flags(char *page_virt, struct ecryptfs_crypt_stat *crypt_stat, |
| 1089 | size_t *written) |
| 1090 | { |
| 1091 | u32 flags = 0; |
| 1092 | int i; |
| 1093 | |
| 1094 | for (i = 0; i < ((sizeof(ecryptfs_flag_map) |
| 1095 | / sizeof(struct ecryptfs_flag_map_elem))); i++) |
| 1096 | if (ECRYPTFS_CHECK_FLAG(crypt_stat->flags, |
| 1097 | ecryptfs_flag_map[i].local_flag)) |
| 1098 | flags |= ecryptfs_flag_map[i].file_flag; |
| 1099 | /* Version is in top 8 bits of the 32-bit flag vector */ |
| 1100 | flags |= ((((u8)crypt_stat->file_version) << 24) & 0xFF000000); |
| 1101 | flags = cpu_to_be32(flags); |
| 1102 | memcpy(page_virt, &flags, 4); |
| 1103 | (*written) = 4; |
| 1104 | } |
| 1105 | |
| 1106 | struct ecryptfs_cipher_code_str_map_elem { |
| 1107 | char cipher_str[16]; |
| 1108 | u16 cipher_code; |
| 1109 | }; |
| 1110 | |
| 1111 | /* Add support for additional ciphers by adding elements here. The |
| 1112 | * cipher_code is whatever OpenPGP applicatoins use to identify the |
| 1113 | * ciphers. List in order of probability. */ |
| 1114 | static struct ecryptfs_cipher_code_str_map_elem |
| 1115 | ecryptfs_cipher_code_str_map[] = { |
| 1116 | {"aes",RFC2440_CIPHER_AES_128 }, |
| 1117 | {"blowfish", RFC2440_CIPHER_BLOWFISH}, |
| 1118 | {"des3_ede", RFC2440_CIPHER_DES3_EDE}, |
| 1119 | {"cast5", RFC2440_CIPHER_CAST_5}, |
| 1120 | {"twofish", RFC2440_CIPHER_TWOFISH}, |
| 1121 | {"cast6", RFC2440_CIPHER_CAST_6}, |
| 1122 | {"aes", RFC2440_CIPHER_AES_192}, |
| 1123 | {"aes", RFC2440_CIPHER_AES_256} |
| 1124 | }; |
| 1125 | |
| 1126 | /** |
| 1127 | * ecryptfs_code_for_cipher_string |
| 1128 | * @str: The string representing the cipher name |
| 1129 | * |
| 1130 | * Returns zero on no match, or the cipher code on match |
| 1131 | */ |
| 1132 | u16 ecryptfs_code_for_cipher_string(struct ecryptfs_crypt_stat *crypt_stat) |
| 1133 | { |
| 1134 | int i; |
| 1135 | u16 code = 0; |
| 1136 | struct ecryptfs_cipher_code_str_map_elem *map = |
| 1137 | ecryptfs_cipher_code_str_map; |
| 1138 | |
| 1139 | if (strcmp(crypt_stat->cipher, "aes") == 0) { |
| 1140 | switch (crypt_stat->key_size) { |
| 1141 | case 16: |
| 1142 | code = RFC2440_CIPHER_AES_128; |
| 1143 | break; |
| 1144 | case 24: |
| 1145 | code = RFC2440_CIPHER_AES_192; |
| 1146 | break; |
| 1147 | case 32: |
| 1148 | code = RFC2440_CIPHER_AES_256; |
| 1149 | } |
| 1150 | } else { |
| 1151 | for (i = 0; i < ARRAY_SIZE(ecryptfs_cipher_code_str_map); i++) |
| 1152 | if (strcmp(crypt_stat->cipher, map[i].cipher_str) == 0){ |
| 1153 | code = map[i].cipher_code; |
| 1154 | break; |
| 1155 | } |
| 1156 | } |
| 1157 | return code; |
| 1158 | } |
| 1159 | |
| 1160 | /** |
| 1161 | * ecryptfs_cipher_code_to_string |
| 1162 | * @str: Destination to write out the cipher name |
| 1163 | * @cipher_code: The code to convert to cipher name string |
| 1164 | * |
| 1165 | * Returns zero on success |
| 1166 | */ |
| 1167 | int ecryptfs_cipher_code_to_string(char *str, u16 cipher_code) |
| 1168 | { |
| 1169 | int rc = 0; |
| 1170 | int i; |
| 1171 | |
| 1172 | str[0] = '\0'; |
| 1173 | for (i = 0; i < ARRAY_SIZE(ecryptfs_cipher_code_str_map); i++) |
| 1174 | if (cipher_code == ecryptfs_cipher_code_str_map[i].cipher_code) |
| 1175 | strcpy(str, ecryptfs_cipher_code_str_map[i].cipher_str); |
| 1176 | if (str[0] == '\0') { |
| 1177 | ecryptfs_printk(KERN_WARNING, "Cipher code not recognized: " |
| 1178 | "[%d]\n", cipher_code); |
| 1179 | rc = -EINVAL; |
| 1180 | } |
| 1181 | return rc; |
| 1182 | } |
| 1183 | |
| 1184 | /** |
| 1185 | * ecryptfs_read_header_region |
| 1186 | * @data |
| 1187 | * @dentry |
| 1188 | * @nd |
| 1189 | * |
| 1190 | * Returns zero on success; non-zero otherwise |
| 1191 | */ |
| 1192 | int ecryptfs_read_header_region(char *data, struct dentry *dentry, |
| 1193 | struct vfsmount *mnt) |
| 1194 | { |
Michael Halcrow | 7ff1d74 | 2006-10-30 22:07:19 -0800 | [diff] [blame] | 1195 | struct file *lower_file; |
Michael Halcrow | 237fead | 2006-10-04 02:16:22 -0700 | [diff] [blame] | 1196 | mm_segment_t oldfs; |
| 1197 | int rc; |
| 1198 | |
Michael Halcrow | 7ff1d74 | 2006-10-30 22:07:19 -0800 | [diff] [blame] | 1199 | if ((rc = ecryptfs_open_lower_file(&lower_file, dentry, mnt, |
| 1200 | O_RDONLY))) { |
| 1201 | printk(KERN_ERR |
| 1202 | "Error opening lower_file to read header region\n"); |
Michael Halcrow | 237fead | 2006-10-04 02:16:22 -0700 | [diff] [blame] | 1203 | goto out; |
| 1204 | } |
Michael Halcrow | 7ff1d74 | 2006-10-30 22:07:19 -0800 | [diff] [blame] | 1205 | lower_file->f_pos = 0; |
Michael Halcrow | 237fead | 2006-10-04 02:16:22 -0700 | [diff] [blame] | 1206 | oldfs = get_fs(); |
| 1207 | set_fs(get_ds()); |
| 1208 | /* For releases 0.1 and 0.2, all of the header information |
| 1209 | * fits in the first data extent-sized region. */ |
Michael Halcrow | 7ff1d74 | 2006-10-30 22:07:19 -0800 | [diff] [blame] | 1210 | rc = lower_file->f_op->read(lower_file, (char __user *)data, |
| 1211 | ECRYPTFS_DEFAULT_EXTENT_SIZE, &lower_file->f_pos); |
Michael Halcrow | 237fead | 2006-10-04 02:16:22 -0700 | [diff] [blame] | 1212 | set_fs(oldfs); |
Michael Halcrow | 7ff1d74 | 2006-10-30 22:07:19 -0800 | [diff] [blame] | 1213 | if ((rc = ecryptfs_close_lower_file(lower_file))) { |
| 1214 | printk(KERN_ERR "Error closing lower_file\n"); |
| 1215 | goto out; |
| 1216 | } |
Michael Halcrow | 237fead | 2006-10-04 02:16:22 -0700 | [diff] [blame] | 1217 | rc = 0; |
| 1218 | out: |
| 1219 | return rc; |
| 1220 | } |
| 1221 | |
| 1222 | static void |
| 1223 | write_header_metadata(char *virt, struct ecryptfs_crypt_stat *crypt_stat, |
| 1224 | size_t *written) |
| 1225 | { |
| 1226 | u32 header_extent_size; |
| 1227 | u16 num_header_extents_at_front; |
| 1228 | |
| 1229 | header_extent_size = (u32)crypt_stat->header_extent_size; |
| 1230 | num_header_extents_at_front = |
| 1231 | (u16)crypt_stat->num_header_extents_at_front; |
| 1232 | header_extent_size = cpu_to_be32(header_extent_size); |
| 1233 | memcpy(virt, &header_extent_size, 4); |
| 1234 | virt += 4; |
| 1235 | num_header_extents_at_front = cpu_to_be16(num_header_extents_at_front); |
| 1236 | memcpy(virt, &num_header_extents_at_front, 2); |
| 1237 | (*written) = 6; |
| 1238 | } |
| 1239 | |
| 1240 | struct kmem_cache *ecryptfs_header_cache_0; |
| 1241 | struct kmem_cache *ecryptfs_header_cache_1; |
| 1242 | struct kmem_cache *ecryptfs_header_cache_2; |
| 1243 | |
| 1244 | /** |
| 1245 | * ecryptfs_write_headers_virt |
| 1246 | * @page_virt |
| 1247 | * @crypt_stat |
| 1248 | * @ecryptfs_dentry |
| 1249 | * |
| 1250 | * Format version: 1 |
| 1251 | * |
| 1252 | * Header Extent: |
| 1253 | * Octets 0-7: Unencrypted file size (big-endian) |
| 1254 | * Octets 8-15: eCryptfs special marker |
| 1255 | * Octets 16-19: Flags |
| 1256 | * Octet 16: File format version number (between 0 and 255) |
| 1257 | * Octets 17-18: Reserved |
| 1258 | * Octet 19: Bit 1 (lsb): Reserved |
| 1259 | * Bit 2: Encrypted? |
| 1260 | * Bits 3-8: Reserved |
| 1261 | * Octets 20-23: Header extent size (big-endian) |
| 1262 | * Octets 24-25: Number of header extents at front of file |
| 1263 | * (big-endian) |
| 1264 | * Octet 26: Begin RFC 2440 authentication token packet set |
| 1265 | * Data Extent 0: |
| 1266 | * Lower data (CBC encrypted) |
| 1267 | * Data Extent 1: |
| 1268 | * Lower data (CBC encrypted) |
| 1269 | * ... |
| 1270 | * |
| 1271 | * Returns zero on success |
| 1272 | */ |
| 1273 | int ecryptfs_write_headers_virt(char *page_virt, |
| 1274 | struct ecryptfs_crypt_stat *crypt_stat, |
| 1275 | struct dentry *ecryptfs_dentry) |
| 1276 | { |
| 1277 | int rc; |
| 1278 | size_t written; |
| 1279 | size_t offset; |
| 1280 | |
| 1281 | offset = ECRYPTFS_FILE_SIZE_BYTES; |
| 1282 | write_ecryptfs_marker((page_virt + offset), &written); |
| 1283 | offset += written; |
| 1284 | write_ecryptfs_flags((page_virt + offset), crypt_stat, &written); |
| 1285 | offset += written; |
| 1286 | write_header_metadata((page_virt + offset), crypt_stat, &written); |
| 1287 | offset += written; |
| 1288 | rc = ecryptfs_generate_key_packet_set((page_virt + offset), crypt_stat, |
| 1289 | ecryptfs_dentry, &written, |
| 1290 | PAGE_CACHE_SIZE - offset); |
| 1291 | if (rc) |
| 1292 | ecryptfs_printk(KERN_WARNING, "Error generating key packet " |
| 1293 | "set; rc = [%d]\n", rc); |
| 1294 | return rc; |
| 1295 | } |
| 1296 | |
| 1297 | /** |
| 1298 | * ecryptfs_write_headers |
| 1299 | * @lower_file: The lower file struct, which was returned from dentry_open |
| 1300 | * |
| 1301 | * Write the file headers out. This will likely involve a userspace |
| 1302 | * callout, in which the session key is encrypted with one or more |
| 1303 | * public keys and/or the passphrase necessary to do the encryption is |
| 1304 | * retrieved via a prompt. Exactly what happens at this point should |
| 1305 | * be policy-dependent. |
| 1306 | * |
| 1307 | * Returns zero on success; non-zero on error |
| 1308 | */ |
| 1309 | int ecryptfs_write_headers(struct dentry *ecryptfs_dentry, |
| 1310 | struct file *lower_file) |
| 1311 | { |
| 1312 | mm_segment_t oldfs; |
| 1313 | struct ecryptfs_crypt_stat *crypt_stat; |
| 1314 | char *page_virt; |
| 1315 | int current_header_page; |
| 1316 | int header_pages; |
| 1317 | int rc = 0; |
| 1318 | |
| 1319 | crypt_stat = &ecryptfs_inode_to_private( |
| 1320 | ecryptfs_dentry->d_inode)->crypt_stat; |
| 1321 | if (likely(ECRYPTFS_CHECK_FLAG(crypt_stat->flags, |
| 1322 | ECRYPTFS_ENCRYPTED))) { |
| 1323 | if (!ECRYPTFS_CHECK_FLAG(crypt_stat->flags, |
| 1324 | ECRYPTFS_KEY_VALID)) { |
| 1325 | ecryptfs_printk(KERN_DEBUG, "Key is " |
| 1326 | "invalid; bailing out\n"); |
| 1327 | rc = -EINVAL; |
| 1328 | goto out; |
| 1329 | } |
| 1330 | } else { |
| 1331 | rc = -EINVAL; |
| 1332 | ecryptfs_printk(KERN_WARNING, |
| 1333 | "Called with crypt_stat->encrypted == 0\n"); |
| 1334 | goto out; |
| 1335 | } |
| 1336 | /* Released in this function */ |
Christoph Lameter | f7267c0 | 2006-12-06 20:33:15 -0800 | [diff] [blame] | 1337 | page_virt = kmem_cache_alloc(ecryptfs_header_cache_0, GFP_USER); |
Michael Halcrow | 237fead | 2006-10-04 02:16:22 -0700 | [diff] [blame] | 1338 | if (!page_virt) { |
| 1339 | ecryptfs_printk(KERN_ERR, "Out of memory\n"); |
| 1340 | rc = -ENOMEM; |
| 1341 | goto out; |
| 1342 | } |
| 1343 | memset(page_virt, 0, PAGE_CACHE_SIZE); |
| 1344 | rc = ecryptfs_write_headers_virt(page_virt, crypt_stat, |
| 1345 | ecryptfs_dentry); |
| 1346 | if (unlikely(rc)) { |
| 1347 | ecryptfs_printk(KERN_ERR, "Error whilst writing headers\n"); |
| 1348 | memset(page_virt, 0, PAGE_CACHE_SIZE); |
| 1349 | goto out_free; |
| 1350 | } |
| 1351 | ecryptfs_printk(KERN_DEBUG, |
| 1352 | "Writing key packet set to underlying file\n"); |
| 1353 | lower_file->f_pos = 0; |
| 1354 | oldfs = get_fs(); |
| 1355 | set_fs(get_ds()); |
| 1356 | ecryptfs_printk(KERN_DEBUG, "Calling lower_file->f_op->" |
| 1357 | "write() w/ header page; lower_file->f_pos = " |
| 1358 | "[0x%.16x]\n", lower_file->f_pos); |
| 1359 | lower_file->f_op->write(lower_file, (char __user *)page_virt, |
| 1360 | PAGE_CACHE_SIZE, &lower_file->f_pos); |
| 1361 | header_pages = ((crypt_stat->header_extent_size |
| 1362 | * crypt_stat->num_header_extents_at_front) |
| 1363 | / PAGE_CACHE_SIZE); |
| 1364 | memset(page_virt, 0, PAGE_CACHE_SIZE); |
| 1365 | current_header_page = 1; |
| 1366 | while (current_header_page < header_pages) { |
| 1367 | ecryptfs_printk(KERN_DEBUG, "Calling lower_file->f_op->" |
| 1368 | "write() w/ zero'd page; lower_file->f_pos = " |
| 1369 | "[0x%.16x]\n", lower_file->f_pos); |
| 1370 | lower_file->f_op->write(lower_file, (char __user *)page_virt, |
| 1371 | PAGE_CACHE_SIZE, &lower_file->f_pos); |
| 1372 | current_header_page++; |
| 1373 | } |
| 1374 | set_fs(oldfs); |
| 1375 | ecryptfs_printk(KERN_DEBUG, |
| 1376 | "Done writing key packet set to underlying file.\n"); |
| 1377 | out_free: |
| 1378 | kmem_cache_free(ecryptfs_header_cache_0, page_virt); |
| 1379 | out: |
| 1380 | return rc; |
| 1381 | } |
| 1382 | |
| 1383 | static int parse_header_metadata(struct ecryptfs_crypt_stat *crypt_stat, |
| 1384 | char *virt, int *bytes_read) |
| 1385 | { |
| 1386 | int rc = 0; |
| 1387 | u32 header_extent_size; |
| 1388 | u16 num_header_extents_at_front; |
| 1389 | |
| 1390 | memcpy(&header_extent_size, virt, 4); |
| 1391 | header_extent_size = be32_to_cpu(header_extent_size); |
| 1392 | virt += 4; |
| 1393 | memcpy(&num_header_extents_at_front, virt, 2); |
| 1394 | num_header_extents_at_front = be16_to_cpu(num_header_extents_at_front); |
| 1395 | crypt_stat->header_extent_size = (int)header_extent_size; |
| 1396 | crypt_stat->num_header_extents_at_front = |
| 1397 | (int)num_header_extents_at_front; |
| 1398 | (*bytes_read) = 6; |
| 1399 | if ((crypt_stat->header_extent_size |
| 1400 | * crypt_stat->num_header_extents_at_front) |
| 1401 | < ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE) { |
| 1402 | rc = -EINVAL; |
| 1403 | ecryptfs_printk(KERN_WARNING, "Invalid header extent size: " |
| 1404 | "[%d]\n", crypt_stat->header_extent_size); |
| 1405 | } |
| 1406 | return rc; |
| 1407 | } |
| 1408 | |
| 1409 | /** |
| 1410 | * set_default_header_data |
| 1411 | * |
| 1412 | * For version 0 file format; this function is only for backwards |
| 1413 | * compatibility for files created with the prior versions of |
| 1414 | * eCryptfs. |
| 1415 | */ |
| 1416 | static void set_default_header_data(struct ecryptfs_crypt_stat *crypt_stat) |
| 1417 | { |
| 1418 | crypt_stat->header_extent_size = 4096; |
| 1419 | crypt_stat->num_header_extents_at_front = 1; |
| 1420 | } |
| 1421 | |
| 1422 | /** |
| 1423 | * ecryptfs_read_headers_virt |
| 1424 | * |
| 1425 | * Read/parse the header data. The header format is detailed in the |
| 1426 | * comment block for the ecryptfs_write_headers_virt() function. |
| 1427 | * |
| 1428 | * Returns zero on success |
| 1429 | */ |
| 1430 | static int ecryptfs_read_headers_virt(char *page_virt, |
| 1431 | struct ecryptfs_crypt_stat *crypt_stat, |
| 1432 | struct dentry *ecryptfs_dentry) |
| 1433 | { |
| 1434 | int rc = 0; |
| 1435 | int offset; |
| 1436 | int bytes_read; |
| 1437 | |
| 1438 | ecryptfs_set_default_sizes(crypt_stat); |
| 1439 | crypt_stat->mount_crypt_stat = &ecryptfs_superblock_to_private( |
| 1440 | ecryptfs_dentry->d_sb)->mount_crypt_stat; |
| 1441 | offset = ECRYPTFS_FILE_SIZE_BYTES; |
| 1442 | rc = contains_ecryptfs_marker(page_virt + offset); |
| 1443 | if (rc == 0) { |
| 1444 | rc = -EINVAL; |
| 1445 | goto out; |
| 1446 | } |
| 1447 | offset += MAGIC_ECRYPTFS_MARKER_SIZE_BYTES; |
| 1448 | rc = ecryptfs_process_flags(crypt_stat, (page_virt + offset), |
| 1449 | &bytes_read); |
| 1450 | if (rc) { |
| 1451 | ecryptfs_printk(KERN_WARNING, "Error processing flags\n"); |
| 1452 | goto out; |
| 1453 | } |
| 1454 | if (crypt_stat->file_version > ECRYPTFS_SUPPORTED_FILE_VERSION) { |
| 1455 | ecryptfs_printk(KERN_WARNING, "File version is [%d]; only " |
| 1456 | "file version [%d] is supported by this " |
| 1457 | "version of eCryptfs\n", |
| 1458 | crypt_stat->file_version, |
| 1459 | ECRYPTFS_SUPPORTED_FILE_VERSION); |
| 1460 | rc = -EINVAL; |
| 1461 | goto out; |
| 1462 | } |
| 1463 | offset += bytes_read; |
| 1464 | if (crypt_stat->file_version >= 1) { |
| 1465 | rc = parse_header_metadata(crypt_stat, (page_virt + offset), |
| 1466 | &bytes_read); |
| 1467 | if (rc) { |
| 1468 | ecryptfs_printk(KERN_WARNING, "Error reading header " |
| 1469 | "metadata; rc = [%d]\n", rc); |
| 1470 | } |
| 1471 | offset += bytes_read; |
| 1472 | } else |
| 1473 | set_default_header_data(crypt_stat); |
| 1474 | rc = ecryptfs_parse_packet_set(crypt_stat, (page_virt + offset), |
| 1475 | ecryptfs_dentry); |
| 1476 | out: |
| 1477 | return rc; |
| 1478 | } |
| 1479 | |
| 1480 | /** |
| 1481 | * ecryptfs_read_headers |
| 1482 | * |
| 1483 | * Returns zero if valid headers found and parsed; non-zero otherwise |
| 1484 | */ |
| 1485 | int ecryptfs_read_headers(struct dentry *ecryptfs_dentry, |
| 1486 | struct file *lower_file) |
| 1487 | { |
| 1488 | int rc = 0; |
| 1489 | char *page_virt = NULL; |
| 1490 | mm_segment_t oldfs; |
| 1491 | ssize_t bytes_read; |
| 1492 | struct ecryptfs_crypt_stat *crypt_stat = |
| 1493 | &ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat; |
| 1494 | |
| 1495 | /* Read the first page from the underlying file */ |
Christoph Lameter | f7267c0 | 2006-12-06 20:33:15 -0800 | [diff] [blame] | 1496 | page_virt = kmem_cache_alloc(ecryptfs_header_cache_1, GFP_USER); |
Michael Halcrow | 237fead | 2006-10-04 02:16:22 -0700 | [diff] [blame] | 1497 | if (!page_virt) { |
| 1498 | rc = -ENOMEM; |
| 1499 | ecryptfs_printk(KERN_ERR, "Unable to allocate page_virt\n"); |
| 1500 | goto out; |
| 1501 | } |
| 1502 | lower_file->f_pos = 0; |
| 1503 | oldfs = get_fs(); |
| 1504 | set_fs(get_ds()); |
| 1505 | bytes_read = lower_file->f_op->read(lower_file, |
| 1506 | (char __user *)page_virt, |
| 1507 | ECRYPTFS_DEFAULT_EXTENT_SIZE, |
| 1508 | &lower_file->f_pos); |
| 1509 | set_fs(oldfs); |
| 1510 | if (bytes_read != ECRYPTFS_DEFAULT_EXTENT_SIZE) { |
| 1511 | rc = -EINVAL; |
| 1512 | goto out; |
| 1513 | } |
| 1514 | rc = ecryptfs_read_headers_virt(page_virt, crypt_stat, |
| 1515 | ecryptfs_dentry); |
| 1516 | if (rc) { |
| 1517 | ecryptfs_printk(KERN_DEBUG, "Valid eCryptfs headers not " |
| 1518 | "found\n"); |
| 1519 | rc = -EINVAL; |
| 1520 | } |
| 1521 | out: |
| 1522 | if (page_virt) { |
| 1523 | memset(page_virt, 0, PAGE_CACHE_SIZE); |
| 1524 | kmem_cache_free(ecryptfs_header_cache_1, page_virt); |
| 1525 | } |
| 1526 | return rc; |
| 1527 | } |
| 1528 | |
| 1529 | /** |
| 1530 | * ecryptfs_encode_filename - converts a plaintext file name to cipher text |
| 1531 | * @crypt_stat: The crypt_stat struct associated with the file anem to encode |
| 1532 | * @name: The plaintext name |
| 1533 | * @length: The length of the plaintext |
| 1534 | * @encoded_name: The encypted name |
| 1535 | * |
| 1536 | * Encrypts and encodes a filename into something that constitutes a |
| 1537 | * valid filename for a filesystem, with printable characters. |
| 1538 | * |
| 1539 | * We assume that we have a properly initialized crypto context, |
| 1540 | * pointed to by crypt_stat->tfm. |
| 1541 | * |
| 1542 | * TODO: Implement filename decoding and decryption here, in place of |
| 1543 | * memcpy. We are keeping the framework around for now to (1) |
| 1544 | * facilitate testing of the components needed to implement filename |
| 1545 | * encryption and (2) to provide a code base from which other |
| 1546 | * developers in the community can easily implement this feature. |
| 1547 | * |
| 1548 | * Returns the length of encoded filename; negative if error |
| 1549 | */ |
| 1550 | int |
| 1551 | ecryptfs_encode_filename(struct ecryptfs_crypt_stat *crypt_stat, |
| 1552 | const char *name, int length, char **encoded_name) |
| 1553 | { |
| 1554 | int error = 0; |
| 1555 | |
| 1556 | (*encoded_name) = kmalloc(length + 2, GFP_KERNEL); |
| 1557 | if (!(*encoded_name)) { |
| 1558 | error = -ENOMEM; |
| 1559 | goto out; |
| 1560 | } |
| 1561 | /* TODO: Filename encryption is a scheduled feature for a |
| 1562 | * future version of eCryptfs. This function is here only for |
| 1563 | * the purpose of providing a framework for other developers |
| 1564 | * to easily implement filename encryption. Hint: Replace this |
| 1565 | * memcpy() with a call to encrypt and encode the |
| 1566 | * filename, the set the length accordingly. */ |
| 1567 | memcpy((void *)(*encoded_name), (void *)name, length); |
| 1568 | (*encoded_name)[length] = '\0'; |
| 1569 | error = length + 1; |
| 1570 | out: |
| 1571 | return error; |
| 1572 | } |
| 1573 | |
| 1574 | /** |
| 1575 | * ecryptfs_decode_filename - converts the cipher text name to plaintext |
| 1576 | * @crypt_stat: The crypt_stat struct associated with the file |
| 1577 | * @name: The filename in cipher text |
| 1578 | * @length: The length of the cipher text name |
| 1579 | * @decrypted_name: The plaintext name |
| 1580 | * |
| 1581 | * Decodes and decrypts the filename. |
| 1582 | * |
| 1583 | * We assume that we have a properly initialized crypto context, |
| 1584 | * pointed to by crypt_stat->tfm. |
| 1585 | * |
| 1586 | * TODO: Implement filename decoding and decryption here, in place of |
| 1587 | * memcpy. We are keeping the framework around for now to (1) |
| 1588 | * facilitate testing of the components needed to implement filename |
| 1589 | * encryption and (2) to provide a code base from which other |
| 1590 | * developers in the community can easily implement this feature. |
| 1591 | * |
| 1592 | * Returns the length of decoded filename; negative if error |
| 1593 | */ |
| 1594 | int |
| 1595 | ecryptfs_decode_filename(struct ecryptfs_crypt_stat *crypt_stat, |
| 1596 | const char *name, int length, char **decrypted_name) |
| 1597 | { |
| 1598 | int error = 0; |
| 1599 | |
| 1600 | (*decrypted_name) = kmalloc(length + 2, GFP_KERNEL); |
| 1601 | if (!(*decrypted_name)) { |
| 1602 | error = -ENOMEM; |
| 1603 | goto out; |
| 1604 | } |
| 1605 | /* TODO: Filename encryption is a scheduled feature for a |
| 1606 | * future version of eCryptfs. This function is here only for |
| 1607 | * the purpose of providing a framework for other developers |
| 1608 | * to easily implement filename encryption. Hint: Replace this |
| 1609 | * memcpy() with a call to decode and decrypt the |
| 1610 | * filename, the set the length accordingly. */ |
| 1611 | memcpy((void *)(*decrypted_name), (void *)name, length); |
| 1612 | (*decrypted_name)[length + 1] = '\0'; /* Only for convenience |
| 1613 | * in printing out the |
| 1614 | * string in debug |
| 1615 | * messages */ |
| 1616 | error = length; |
| 1617 | out: |
| 1618 | return error; |
| 1619 | } |
| 1620 | |
| 1621 | /** |
| 1622 | * ecryptfs_process_cipher - Perform cipher initialization. |
Michael Halcrow | 237fead | 2006-10-04 02:16:22 -0700 | [diff] [blame] | 1623 | * @key_tfm: Crypto context for key material, set by this function |
Michael Halcrow | e5d9cbd | 2006-10-30 22:07:16 -0800 | [diff] [blame] | 1624 | * @cipher_name: Name of the cipher |
| 1625 | * @key_size: Size of the key in bytes |
Michael Halcrow | 237fead | 2006-10-04 02:16:22 -0700 | [diff] [blame] | 1626 | * |
| 1627 | * Returns zero on success. Any crypto_tfm structs allocated here |
| 1628 | * should be released by other functions, such as on a superblock put |
| 1629 | * event, regardless of whether this function succeeds for fails. |
| 1630 | */ |
| 1631 | int |
Michael Halcrow | 8bba066 | 2006-10-30 22:07:18 -0800 | [diff] [blame] | 1632 | ecryptfs_process_cipher(struct crypto_blkcipher **key_tfm, char *cipher_name, |
Michael Halcrow | e5d9cbd | 2006-10-30 22:07:16 -0800 | [diff] [blame] | 1633 | size_t *key_size) |
Michael Halcrow | 237fead | 2006-10-04 02:16:22 -0700 | [diff] [blame] | 1634 | { |
| 1635 | char dummy_key[ECRYPTFS_MAX_KEY_BYTES]; |
Michael Halcrow | 8bba066 | 2006-10-30 22:07:18 -0800 | [diff] [blame] | 1636 | char *full_alg_name; |
Michael Halcrow | 237fead | 2006-10-04 02:16:22 -0700 | [diff] [blame] | 1637 | int rc; |
| 1638 | |
Michael Halcrow | e5d9cbd | 2006-10-30 22:07:16 -0800 | [diff] [blame] | 1639 | *key_tfm = NULL; |
| 1640 | if (*key_size > ECRYPTFS_MAX_KEY_BYTES) { |
Michael Halcrow | 237fead | 2006-10-04 02:16:22 -0700 | [diff] [blame] | 1641 | rc = -EINVAL; |
| 1642 | printk(KERN_ERR "Requested key size is [%Zd] bytes; maximum " |
Michael Halcrow | e5d9cbd | 2006-10-30 22:07:16 -0800 | [diff] [blame] | 1643 | "allowable is [%d]\n", *key_size, ECRYPTFS_MAX_KEY_BYTES); |
Michael Halcrow | 237fead | 2006-10-04 02:16:22 -0700 | [diff] [blame] | 1644 | goto out; |
| 1645 | } |
Michael Halcrow | 8bba066 | 2006-10-30 22:07:18 -0800 | [diff] [blame] | 1646 | rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name, cipher_name, |
| 1647 | "ecb"); |
| 1648 | if (rc) |
| 1649 | goto out; |
| 1650 | *key_tfm = crypto_alloc_blkcipher(full_alg_name, 0, CRYPTO_ALG_ASYNC); |
| 1651 | kfree(full_alg_name); |
| 1652 | if (IS_ERR(*key_tfm)) { |
| 1653 | rc = PTR_ERR(*key_tfm); |
Michael Halcrow | 237fead | 2006-10-04 02:16:22 -0700 | [diff] [blame] | 1654 | printk(KERN_ERR "Unable to allocate crypto cipher with name " |
Michael Halcrow | 8bba066 | 2006-10-30 22:07:18 -0800 | [diff] [blame] | 1655 | "[%s]; rc = [%d]\n", cipher_name, rc); |
Michael Halcrow | 237fead | 2006-10-04 02:16:22 -0700 | [diff] [blame] | 1656 | goto out; |
| 1657 | } |
Michael Halcrow | 8bba066 | 2006-10-30 22:07:18 -0800 | [diff] [blame] | 1658 | crypto_blkcipher_set_flags(*key_tfm, CRYPTO_TFM_REQ_WEAK_KEY); |
| 1659 | if (*key_size == 0) { |
| 1660 | struct blkcipher_alg *alg = crypto_blkcipher_alg(*key_tfm); |
| 1661 | |
| 1662 | *key_size = alg->max_keysize; |
| 1663 | } |
Michael Halcrow | e5d9cbd | 2006-10-30 22:07:16 -0800 | [diff] [blame] | 1664 | get_random_bytes(dummy_key, *key_size); |
Michael Halcrow | 8bba066 | 2006-10-30 22:07:18 -0800 | [diff] [blame] | 1665 | rc = crypto_blkcipher_setkey(*key_tfm, dummy_key, *key_size); |
Michael Halcrow | 237fead | 2006-10-04 02:16:22 -0700 | [diff] [blame] | 1666 | if (rc) { |
| 1667 | printk(KERN_ERR "Error attempting to set key of size [%Zd] for " |
Michael Halcrow | e5d9cbd | 2006-10-30 22:07:16 -0800 | [diff] [blame] | 1668 | "cipher [%s]; rc = [%d]\n", *key_size, cipher_name, rc); |
Michael Halcrow | 237fead | 2006-10-04 02:16:22 -0700 | [diff] [blame] | 1669 | rc = -EINVAL; |
| 1670 | goto out; |
| 1671 | } |
| 1672 | out: |
| 1673 | return rc; |
| 1674 | } |