fs/ecryptfs/crypto.c

   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) 2004-2007 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 <linux/slab.h>
  37 #include <asm/unaligned.h>
  38 #include "ecryptfs_kernel.h"
  39
  40 static int
  41 ecryptfs_decrypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat,
  42                              struct page *dst_page, int dst_offset,
  43                              struct page *src_page, int src_offset, int size,
  44                              unsigned char *iv);
  45 static int
  46 ecryptfs_encrypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat,
  47                              struct page *dst_page, int dst_offset,
  48                              struct page *src_page, int src_offset, int size,
  49                              unsigned char *iv);
  50
  51 /**
  52  * ecryptfs_to_hex
  53  * @dst: Buffer to take hex character representation of contents of
  54  *       src; must be at least of size (src_size * 2)
  55  * @src: Buffer to be converted to a hex string respresentation
  56  * @src_size: number of bytes to convert
  57  */
  58 void ecryptfs_to_hex(char *dst, char *src, size_t src_size)
  59 {
  60         int x;
  61
  62         for (x = 0; x < src_size; x++)
  63                 sprintf(&dst[x * 2], "%.2x", (unsigned char)src[x]);
  64 }
  65
  66 /**
  67  * ecryptfs_from_hex
  68  * @dst: Buffer to take the bytes from src hex; must be at least of
  69  *       size (src_size / 2)
  70  * @src: Buffer to be converted from a hex string respresentation to raw value
  71  * @dst_size: size of dst buffer, or number of hex characters pairs to convert
  72  */
  73 void ecryptfs_from_hex(char *dst, char *src, int dst_size)
  74 {
  75         int x;
  76         char tmp[3] = { 0, };
  77
  78         for (x = 0; x < dst_size; x++) {
  79                 tmp[0] = src[x * 2];
  80                 tmp[1] = src[x * 2 + 1];
  81                 dst[x] = (unsigned char)simple_strtol(tmp, NULL, 16);
  82         }
  83 }
  84
  85 /**
  86  * ecryptfs_calculate_md5 - calculates the md5 of @src
  87  * @dst: Pointer to 16 bytes of allocated memory
  88  * @crypt_stat: Pointer to crypt_stat struct for the current inode
  89  * @src: Data to be md5'd
  90  * @len: Length of @src
  91  *
  92  * Uses the allocated crypto context that crypt_stat references to
  93  * generate the MD5 sum of the contents of src.
  94  */
  95 static int ecryptfs_calculate_md5(char *dst,
  96                                   struct ecryptfs_crypt_stat *crypt_stat,
  97                                   char *src, int len)
  98 {
  99         struct scatterlist sg;
 100         struct hash_desc desc = {
 101                 .tfm = crypt_stat->hash_tfm,
 102                 .flags = CRYPTO_TFM_REQ_MAY_SLEEP
 103         };
 104         int rc = 0;
 105
 106         mutex_lock(&crypt_stat->cs_hash_tfm_mutex);
 107         sg_init_one(&sg, (u8 *)src, len);
 108         if (!desc.tfm) {
 109                 desc.tfm = crypto_alloc_hash(ECRYPTFS_DEFAULT_HASH, 0,
 110                                              CRYPTO_ALG_ASYNC);
 111                 if (IS_ERR(desc.tfm)) {
 112                         rc = PTR_ERR(desc.tfm);
 113                         ecryptfs_printk(KERN_ERR, "Error attempting to "
 114                                         "allocate crypto context; rc = [%d]\n",
 115                                         rc);
 116                         goto out;
 117                 }
 118                 crypt_stat->hash_tfm = desc.tfm;
 119         }
 120         rc = crypto_hash_init(&desc);
 121         if (rc) {
 122                 printk(KERN_ERR
 123                        "%s: Error initializing crypto hash; rc = [%d]\n",
 124                        __func__, rc);
 125                 goto out;
 126         }
 127         rc = crypto_hash_update(&desc, &sg, len);
 128         if (rc) {
 129                 printk(KERN_ERR
 130                        "%s: Error updating crypto hash; rc = [%d]\n",
 131                        __func__, rc);
 132                 goto out;
 133         }
 134         rc = crypto_hash_final(&desc, dst);
 135         if (rc) {
 136                 printk(KERN_ERR
 137                        "%s: Error finalizing crypto hash; rc = [%d]\n",
 138                        __func__, rc);
 139                 goto out;
 140         }
 141 out:
 142         mutex_unlock(&crypt_stat->cs_hash_tfm_mutex);
 143         return rc;
 144 }
 145
 146 static int ecryptfs_crypto_api_algify_cipher_name(char **algified_name,
 147                                                   char *cipher_name,
 148                                                   char *chaining_modifier)
 149 {
 150         int cipher_name_len = strlen(cipher_name);
 151         int chaining_modifier_len = strlen(chaining_modifier);
 152         int algified_name_len;
 153         int rc;
 154
 155         algified_name_len = (chaining_modifier_len + cipher_name_len + 3);
 156         (*algified_name) = kmalloc(algified_name_len, GFP_KERNEL);
 157         if (!(*algified_name)) {
 158                 rc = -ENOMEM;
 159                 goto out;
 160         }
 161         snprintf((*algified_name), algified_name_len, "%s(%s)",
 162                  chaining_modifier, cipher_name);
 163         rc = 0;
 164 out:
 165         return rc;
 166 }
 167
 168 /**
 169  * ecryptfs_derive_iv
 170  * @iv: destination for the derived iv vale
 171  * @crypt_stat: Pointer to crypt_stat struct for the current inode
 172  * @offset: Offset of the extent whose IV we are to derive
 173  *
 174  * Generate the initialization vector from the given root IV and page
 175  * offset.
 176  *
 177  * Returns zero on success; non-zero on error.
 178  */
 179 int ecryptfs_derive_iv(char *iv, struct ecryptfs_crypt_stat *crypt_stat,
 180                        loff_t offset)
 181 {
 182         int rc = 0;
 183         char dst[MD5_DIGEST_SIZE];
 184         char src[ECRYPTFS_MAX_IV_BYTES + 16];
 185
 186         if (unlikely(ecryptfs_verbosity > 0)) {
 187                 ecryptfs_printk(KERN_DEBUG, "root iv:\n");
 188                 ecryptfs_dump_hex(crypt_stat->root_iv, crypt_stat->iv_bytes);
 189         }
 190         /* TODO: It is probably secure to just cast the least
 191          * significant bits of the root IV into an unsigned long and
 192          * add the offset to that rather than go through all this
 193          * hashing business. -Halcrow */
 194         memcpy(src, crypt_stat->root_iv, crypt_stat->iv_bytes);
 195         memset((src + crypt_stat->iv_bytes), 0, 16);
 196         snprintf((src + crypt_stat->iv_bytes), 16, "%lld", offset);
 197         if (unlikely(ecryptfs_verbosity > 0)) {
 198                 ecryptfs_printk(KERN_DEBUG, "source:\n");
 199                 ecryptfs_dump_hex(src, (crypt_stat->iv_bytes + 16));
 200         }
 201         rc = ecryptfs_calculate_md5(dst, crypt_stat, src,
 202                                     (crypt_stat->iv_bytes + 16));
 203         if (rc) {
 204                 ecryptfs_printk(KERN_WARNING, "Error attempting to compute "
 205                                 "MD5 while generating IV for a page\n");
 206                 goto out;
 207         }
 208         memcpy(iv, dst, crypt_stat->iv_bytes);
 209         if (unlikely(ecryptfs_verbosity > 0)) {
 210                 ecryptfs_printk(KERN_DEBUG, "derived iv:\n");
 211                 ecryptfs_dump_hex(iv, crypt_stat->iv_bytes);
 212         }
 213 out:
 214         return rc;
 215 }
 216
 217 /**
 218  * ecryptfs_init_crypt_stat
 219  * @crypt_stat: Pointer to the crypt_stat struct to initialize.
 220  *
 221  * Initialize the crypt_stat structure.
 222  */
 223 void
 224 ecryptfs_init_crypt_stat(struct ecryptfs_crypt_stat *crypt_stat)
 225 {
 226         memset((void *)crypt_stat, 0, sizeof(struct ecryptfs_crypt_stat));
 227         INIT_LIST_HEAD(&crypt_stat->keysig_list);
 228         mutex_init(&crypt_stat->keysig_list_mutex);
 229         mutex_init(&crypt_stat->cs_mutex);
 230         mutex_init(&crypt_stat->cs_tfm_mutex);
 231         mutex_init(&crypt_stat->cs_hash_tfm_mutex);
 232         crypt_stat->flags |= ECRYPTFS_STRUCT_INITIALIZED;
 233 }
 234
 235 /**
 236  * ecryptfs_destroy_crypt_stat
 237  * @crypt_stat: Pointer to the crypt_stat struct to initialize.
 238  *
 239  * Releases all memory associated with a crypt_stat struct.
 240  */
 241 void ecryptfs_destroy_crypt_stat(struct ecryptfs_crypt_stat *crypt_stat)
 242 {
 243         struct ecryptfs_key_sig *key_sig, *key_sig_tmp;
 244
 245         if (crypt_stat->tfm)
 246                 crypto_free_blkcipher(crypt_stat->tfm);
 247         if (crypt_stat->hash_tfm)
 248                 crypto_free_hash(crypt_stat->hash_tfm);
 249         list_for_each_entry_safe(key_sig, key_sig_tmp,
 250                                  &crypt_stat->keysig_list, crypt_stat_list) {
 251                 list_del(&key_sig->crypt_stat_list);
 252                 kmem_cache_free(ecryptfs_key_sig_cache, key_sig);
 253         }
 254         memset(crypt_stat, 0, sizeof(struct ecryptfs_crypt_stat));
 255 }
 256
 257 void ecryptfs_destroy_mount_crypt_stat(
 258         struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
 259 {
 260         struct ecryptfs_global_auth_tok *auth_tok, *auth_tok_tmp;
 261
 262         if (!(mount_crypt_stat->flags & ECRYPTFS_MOUNT_CRYPT_STAT_INITIALIZED))
 263                 return;
 264         mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
 265         list_for_each_entry_safe(auth_tok, auth_tok_tmp,
 266                                  &mount_crypt_stat->global_auth_tok_list,
 267                                  mount_crypt_stat_list) {
 268                 list_del(&auth_tok->mount_crypt_stat_list);
 269                 if (auth_tok->global_auth_tok_key
 270                     && !(auth_tok->flags & ECRYPTFS_AUTH_TOK_INVALID))
 271                         key_put(auth_tok->global_auth_tok_key);
 272                 kmem_cache_free(ecryptfs_global_auth_tok_cache, auth_tok);
 273         }
 274         mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
 275         memset(mount_crypt_stat, 0, sizeof(struct ecryptfs_mount_crypt_stat));
 276 }
 277
 278 /**
 279  * virt_to_scatterlist
 280  * @addr: Virtual address
 281  * @size: Size of data; should be an even multiple of the block size
 282  * @sg: Pointer to scatterlist array; set to NULL to obtain only
 283  *      the number of scatterlist structs required in array
 284  * @sg_size: Max array size
 285  *
 286  * Fills in a scatterlist array with page references for a passed
 287  * virtual address.
 288  *
 289  * Returns the number of scatterlist structs in array used
 290  */
 291 int virt_to_scatterlist(const void *addr, int size, struct scatterlist *sg,
 292                         int sg_size)
 293 {
 294         int i = 0;
 295         struct page *pg;
 296         int offset;
 297         int remainder_of_page;
 298
 299         sg_init_table(sg, sg_size);
 300
 301         while (size > 0 && i < sg_size) {
 302                 pg = virt_to_page(addr);
 303                 offset = offset_in_page(addr);
 304                 if (sg)
 305                         sg_set_page(&sg[i], pg, 0, offset);
 306                 remainder_of_page = PAGE_CACHE_SIZE - offset;
 307                 if (size >= remainder_of_page) {
 308                         if (sg)
 309                                 sg[i].length = remainder_of_page;
 310                         addr += remainder_of_page;
 311                         size -= remainder_of_page;
 312                 } else {
 313                         if (sg)
 314                                 sg[i].length = size;
 315                         addr += size;
 316                         size = 0;
 317                 }
 318                 i++;
 319         }
 320         if (size > 0)
 321                 return -ENOMEM;
 322         return i;
 323 }
 324
 325 /**
 326  * encrypt_scatterlist
 327  * @crypt_stat: Pointer to the crypt_stat struct to initialize.
 328  * @dest_sg: Destination of encrypted data
 329  * @src_sg: Data to be encrypted
 330  * @size: Length of data to be encrypted
 331  * @iv: iv to use during encryption
 332  *
 333  * Returns the number of bytes encrypted; negative value on error
 334  */
 335 static int encrypt_scatterlist(struct ecryptfs_crypt_stat *crypt_stat,
 336                                struct scatterlist *dest_sg,
 337                                struct scatterlist *src_sg, int size,
 338                                unsigned char *iv)
 339 {
 340         struct blkcipher_desc desc = {
 341                 .tfm = crypt_stat->tfm,
 342                 .info = iv,
 343                 .flags = CRYPTO_TFM_REQ_MAY_SLEEP
 344         };
 345         int rc = 0;
 346
 347         BUG_ON(!crypt_stat || !crypt_stat->tfm
 348                || !(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED));
 349         if (unlikely(ecryptfs_verbosity > 0)) {
 350                 ecryptfs_printk(KERN_DEBUG, "Key size [%zd]; key:\n",
 351                                 crypt_stat->key_size);
 352                 ecryptfs_dump_hex(crypt_stat->key,
 353                                   crypt_stat->key_size);
 354         }
 355         /* Consider doing this once, when the file is opened */
 356         mutex_lock(&crypt_stat->cs_tfm_mutex);
 357         if (!(crypt_stat->flags & ECRYPTFS_KEY_SET)) {
 358                 rc = crypto_blkcipher_setkey(crypt_stat->tfm, crypt_stat->key,
 359                                              crypt_stat->key_size);
 360                 crypt_stat->flags |= ECRYPTFS_KEY_SET;
 361         }
 362         if (rc) {
 363                 ecryptfs_printk(KERN_ERR, "Error setting key; rc = [%d]\n",
 364                                 rc);
 365                 mutex_unlock(&crypt_stat->cs_tfm_mutex);
 366                 rc = -EINVAL;
 367                 goto out;
 368         }
 369         ecryptfs_printk(KERN_DEBUG, "Encrypting [%d] bytes.\n", size);
 370         crypto_blkcipher_encrypt_iv(&desc, dest_sg, src_sg, size);
 371         mutex_unlock(&crypt_stat->cs_tfm_mutex);
 372 out:
 373         return rc;
 374 }
 375
 376 /**
 377  * ecryptfs_lower_offset_for_extent
 378  *
 379  * Convert an eCryptfs page index into a lower byte offset
 380  */
 381 static void ecryptfs_lower_offset_for_extent(loff_t *offset, loff_t extent_num,
 382                                              struct ecryptfs_crypt_stat *crypt_stat)
 383 {
 384         (*offset) = ecryptfs_lower_header_size(crypt_stat)
 385                     + (crypt_stat->extent_size * extent_num);
 386 }
 387
 388 /**
 389  * ecryptfs_encrypt_extent
 390  * @enc_extent_page: Allocated page into which to encrypt the data in
 391  *                   @page
 392  * @crypt_stat: crypt_stat containing cryptographic context for the
 393  *              encryption operation
 394  * @page: Page containing plaintext data extent to encrypt
 395  * @extent_offset: Page extent offset for use in generating IV
 396  *
 397  * Encrypts one extent of data.
 398  *
 399  * Return zero on success; non-zero otherwise
 400  */
 401 static int ecryptfs_encrypt_extent(struct page *enc_extent_page,
 402                                    struct ecryptfs_crypt_stat *crypt_stat,
 403                                    struct page *page,
 404                                    unsigned long extent_offset)
 405 {
 406         loff_t extent_base;
 407         char extent_iv[ECRYPTFS_MAX_IV_BYTES];
 408         int rc;
 409
 410         extent_base = (((loff_t)page->index)
 411                        * (PAGE_CACHE_SIZE / crypt_stat->extent_size));
 412         rc = ecryptfs_derive_iv(extent_iv, crypt_stat,
 413                                 (extent_base + extent_offset));
 414         if (rc) {
 415                 ecryptfs_printk(KERN_ERR, "Error attempting to derive IV for "
 416                         "extent [0x%.16llx]; rc = [%d]\n",
 417                         (unsigned long long)(extent_base + extent_offset), rc);
 418                 goto out;
 419         }
 420         rc = ecryptfs_encrypt_page_offset(crypt_stat, enc_extent_page, 0,
 421                                           page, (extent_offset
 422                                                  * crypt_stat->extent_size),
 423                                           crypt_stat->extent_size, extent_iv);
 424         if (rc < 0) {
 425                 printk(KERN_ERR "%s: Error attempting to encrypt page with "
 426                        "page->index = [%ld], extent_offset = [%ld]; "
 427                        "rc = [%d]\n", __func__, page->index, extent_offset,
 428                        rc);
 429                 goto out;
 430         }
 431         rc = 0;
 432 out:
 433         return rc;
 434 }
 435
 436 /**
 437  * ecryptfs_encrypt_page
 438  * @page: Page mapped from the eCryptfs inode for the file; contains
 439  *        decrypted content that needs to be encrypted (to a temporary
 440  *        page; not in place) and written out to the lower file
 441  *
 442  * Encrypt an eCryptfs page. This is done on a per-extent basis. Note
 443  * that eCryptfs pages may straddle the lower pages -- for instance,
 444  * if the file was created on a machine with an 8K page size
 445  * (resulting in an 8K header), and then the file is copied onto a
 446  * host with a 32K page size, then when reading page 0 of the eCryptfs
 447  * file, 24K of page 0 of the lower file will be read and decrypted,
 448  * and then 8K of page 1 of the lower file will be read and decrypted.
 449  *
 450  * Returns zero on success; negative on error
 451  */
 452 int ecryptfs_encrypt_page(struct page *page)
 453 {
 454         struct inode *ecryptfs_inode;
 455         struct ecryptfs_crypt_stat *crypt_stat;
 456         char *enc_extent_virt;
 457         struct page *enc_extent_page = NULL;
 458         loff_t extent_offset;
 459         int rc = 0;
 460
 461         ecryptfs_inode = page->mapping->host;
 462         crypt_stat =
 463                 &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat);
 464         BUG_ON(!(crypt_stat->flags & ECRYPTFS_ENCRYPTED));
 465         enc_extent_page = alloc_page(GFP_USER);
 466         if (!enc_extent_page) {
 467                 rc = -ENOMEM;
 468                 ecryptfs_printk(KERN_ERR, "Error allocating memory for "
 469                                 "encrypted extent\n");
 470                 goto out;
 471         }
 472         enc_extent_virt = kmap(enc_extent_page);
 473         for (extent_offset = 0;
 474              extent_offset < (PAGE_CACHE_SIZE / crypt_stat->extent_size);
 475              extent_offset++) {
 476                 loff_t offset;
 477
 478                 rc = ecryptfs_encrypt_extent(enc_extent_page, crypt_stat, page,
 479                                              extent_offset);
 480                 if (rc) {
 481                         printk(KERN_ERR "%s: Error encrypting extent; "
 482                                "rc = [%d]\n", __func__, rc);
 483                         goto out;
 484                 }
 485                 ecryptfs_lower_offset_for_extent(
 486                         &offset, ((((loff_t)page->index)
 487                                    * (PAGE_CACHE_SIZE
 488                                       / crypt_stat->extent_size))
 489                                   + extent_offset), crypt_stat);
 490                 rc = ecryptfs_write_lower(ecryptfs_inode, enc_extent_virt,
 491                                           offset, crypt_stat->extent_size);
 492                 if (rc < 0) {
 493                         ecryptfs_printk(KERN_ERR, "Error attempting "
 494                                         "to write lower page; rc = [%d]"
 495                                         "\n", rc);
 496                         goto out;
 497                 }
 498         }
 499         rc = 0;
 500 out:
 501         if (enc_extent_page) {
 502                 kunmap(enc_extent_page);
 503                 __free_page(enc_extent_page);
 504         }
 505         return rc;
 506 }
 507
 508 static int ecryptfs_decrypt_extent(struct page *page,
 509                                    struct ecryptfs_crypt_stat *crypt_stat,
 510                                    struct page *enc_extent_page,
 511                                    unsigned long extent_offset)
 512 {
 513         loff_t extent_base;
 514         char extent_iv[ECRYPTFS_MAX_IV_BYTES];
 515         int rc;
 516
 517         extent_base = (((loff_t)page->index)
 518                        * (PAGE_CACHE_SIZE / crypt_stat->extent_size));
 519         rc = ecryptfs_derive_iv(extent_iv, crypt_stat,
 520                                 (extent_base + extent_offset));
 521         if (rc) {
 522                 ecryptfs_printk(KERN_ERR, "Error attempting to derive IV for "
 523                         "extent [0x%.16llx]; rc = [%d]\n",
 524                         (unsigned long long)(extent_base + extent_offset), rc);
 525                 goto out;
 526         }
 527         rc = ecryptfs_decrypt_page_offset(crypt_stat, page,
 528                                           (extent_offset
 529                                            * crypt_stat->extent_size),
 530                                           enc_extent_page, 0,
 531                                           crypt_stat->extent_size, extent_iv);
 532         if (rc < 0) {
 533                 printk(KERN_ERR "%s: Error attempting to decrypt to page with "
 534                        "page->index = [%ld], extent_offset = [%ld]; "
 535                        "rc = [%d]\n", __func__, page->index, extent_offset,
 536                        rc);
 537                 goto out;
 538         }
 539         rc = 0;
 540 out:
 541         return rc;
 542 }
 543
 544 /**
 545  * ecryptfs_decrypt_page
 546  * @page: Page mapped from the eCryptfs inode for the file; data read
 547  *        and decrypted from the lower file will be written into this
 548  *        page
 549  *
 550  * Decrypt an eCryptfs page. This is done on a per-extent basis. Note
 551  * that eCryptfs pages may straddle the lower pages -- for instance,
 552  * if the file was created on a machine with an 8K page size
 553  * (resulting in an 8K header), and then the file is copied onto a
 554  * host with a 32K page size, then when reading page 0 of the eCryptfs
 555  * file, 24K of page 0 of the lower file will be read and decrypted,
 556  * and then 8K of page 1 of the lower file will be read and decrypted.
 557  *
 558  * Returns zero on success; negative on error
 559  */
 560 int ecryptfs_decrypt_page(struct page *page)
 561 {
 562         struct inode *ecryptfs_inode;
 563         struct ecryptfs_crypt_stat *crypt_stat;
 564         char *enc_extent_virt;
 565         struct page *enc_extent_page = NULL;
 566         unsigned long extent_offset;
 567         int rc = 0;
 568
 569         ecryptfs_inode = page->mapping->host;
 570         crypt_stat =
 571                 &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat);
 572         BUG_ON(!(crypt_stat->flags & ECRYPTFS_ENCRYPTED));
 573         enc_extent_page = alloc_page(GFP_USER);
 574         if (!enc_extent_page) {
 575                 rc = -ENOMEM;
 576                 ecryptfs_printk(KERN_ERR, "Error allocating memory for "
 577                                 "encrypted extent\n");
 578                 goto out;
 579         }
 580         enc_extent_virt = kmap(enc_extent_page);
 581         for (extent_offset = 0;
 582              extent_offset < (PAGE_CACHE_SIZE / crypt_stat->extent_size);
 583              extent_offset++) {
 584                 loff_t offset;
 585
 586                 ecryptfs_lower_offset_for_extent(
 587                         &offset, ((page->index * (PAGE_CACHE_SIZE
 588                                                   / crypt_stat->extent_size))
 589                                   + extent_offset), crypt_stat);
 590                 rc = ecryptfs_read_lower(enc_extent_virt, offset,
 591                                          crypt_stat->extent_size,
 592                                          ecryptfs_inode);
 593                 if (rc < 0) {
 594                         ecryptfs_printk(KERN_ERR, "Error attempting "
 595                                         "to read lower page; rc = [%d]"
 596                                         "\n", rc);
 597                         goto out;
 598                 }
 599                 rc = ecryptfs_decrypt_extent(page, crypt_stat, enc_extent_page,
 600                                              extent_offset);
 601                 if (rc) {
 602                         printk(KERN_ERR "%s: Error encrypting extent; "
 603                                "rc = [%d]\n", __func__, rc);
 604                         goto out;
 605                 }
 606         }
 607 out:
 608         if (enc_extent_page) {
 609                 kunmap(enc_extent_page);
 610                 __free_page(enc_extent_page);
 611         }
 612         return rc;
 613 }
 614
 615 /**
 616  * decrypt_scatterlist
 617  * @crypt_stat: Cryptographic context
 618  * @dest_sg: The destination scatterlist to decrypt into
 619  * @src_sg: The source scatterlist to decrypt from
 620  * @size: The number of bytes to decrypt
 621  * @iv: The initialization vector to use for the decryption
 622  *
 623  * Returns the number of bytes decrypted; negative value on error
 624  */
 625 static int decrypt_scatterlist(struct ecryptfs_crypt_stat *crypt_stat,
 626                                struct scatterlist *dest_sg,
 627                                struct scatterlist *src_sg, int size,
 628                                unsigned char *iv)
 629 {
 630         struct blkcipher_desc desc = {
 631                 .tfm = crypt_stat->tfm,
 632                 .info = iv,
 633                 .flags = CRYPTO_TFM_REQ_MAY_SLEEP
 634         };
 635         int rc = 0;
 636
 637         /* Consider doing this once, when the file is opened */
 638         mutex_lock(&crypt_stat->cs_tfm_mutex);
 639         rc = crypto_blkcipher_setkey(crypt_stat->tfm, crypt_stat->key,
 640                                      crypt_stat->key_size);
 641         if (rc) {
 642                 ecryptfs_printk(KERN_ERR, "Error setting key; rc = [%d]\n",
 643                                 rc);
 644                 mutex_unlock(&crypt_stat->cs_tfm_mutex);
 645                 rc = -EINVAL;
 646                 goto out;
 647         }
 648         ecryptfs_printk(KERN_DEBUG, "Decrypting [%d] bytes.\n", size);
 649         rc = crypto_blkcipher_decrypt_iv(&desc, dest_sg, src_sg, size);
 650         mutex_unlock(&crypt_stat->cs_tfm_mutex);
 651         if (rc) {
 652                 ecryptfs_printk(KERN_ERR, "Error decrypting; rc = [%d]\n",
 653                                 rc);
 654                 goto out;
 655         }
 656         rc = size;
 657 out:
 658         return rc;
 659 }
 660
 661 /**
 662  * ecryptfs_encrypt_page_offset
 663  * @crypt_stat: The cryptographic context
 664  * @dst_page: The page to encrypt into
 665  * @dst_offset: The offset in the page to encrypt into
 666  * @src_page: The page to encrypt from
 667  * @src_offset: The offset in the page to encrypt from
 668  * @size: The number of bytes to encrypt
 669  * @iv: The initialization vector to use for the encryption
 670  *
 671  * Returns the number of bytes encrypted
 672  */
 673 static int
 674 ecryptfs_encrypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat,
 675                              struct page *dst_page, int dst_offset,
 676                              struct page *src_page, int src_offset, int size,
 677                              unsigned char *iv)
 678 {
 679         struct scatterlist src_sg, dst_sg;
 680
 681         sg_init_table(&src_sg, 1);
 682         sg_init_table(&dst_sg, 1);
 683
 684         sg_set_page(&src_sg, src_page, size, src_offset);
 685         sg_set_page(&dst_sg, dst_page, size, dst_offset);
 686         return encrypt_scatterlist(crypt_stat, &dst_sg, &src_sg, size, iv);
 687 }
 688
 689 /**
 690  * ecryptfs_decrypt_page_offset
 691  * @crypt_stat: The cryptographic context
 692  * @dst_page: The page to decrypt into
 693  * @dst_offset: The offset in the page to decrypt into
 694  * @src_page: The page to decrypt from
 695  * @src_offset: The offset in the page to decrypt from
 696  * @size: The number of bytes to decrypt
 697  * @iv: The initialization vector to use for the decryption
 698  *
 699  * Returns the number of bytes decrypted
 700  */
 701 static int
 702 ecryptfs_decrypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat,
 703                              struct page *dst_page, int dst_offset,
 704                              struct page *src_page, int src_offset, int size,
 705                              unsigned char *iv)
 706 {
 707         struct scatterlist src_sg, dst_sg;
 708
 709         sg_init_table(&src_sg, 1);
 710         sg_set_page(&src_sg, src_page, size, src_offset);
 711
 712         sg_init_table(&dst_sg, 1);
 713         sg_set_page(&dst_sg, dst_page, size, dst_offset);
 714
 715         return decrypt_scatterlist(crypt_stat, &dst_sg, &src_sg, size, iv);
 716 }
 717
 718 #define ECRYPTFS_MAX_SCATTERLIST_LEN 4
 719
 720 /**
 721  * ecryptfs_init_crypt_ctx
 722  * @crypt_stat: Uninitialized crypt stats structure
 723  *
 724  * Initialize the crypto context.
 725  *
 726  * TODO: Performance: Keep a cache of initialized cipher contexts;
 727  * only init if needed
 728  */
 729 int ecryptfs_init_crypt_ctx(struct ecryptfs_crypt_stat *crypt_stat)
 730 {
 731         char *full_alg_name;
 732         int rc = -EINVAL;
 733
 734         if (!crypt_stat->cipher) {
 735                 ecryptfs_printk(KERN_ERR, "No cipher specified\n");
 736                 goto out;
 737         }
 738         ecryptfs_printk(KERN_DEBUG,
 739                         "Initializing cipher [%s]; strlen = [%d]; "
 740                         "key_size_bits = [%zd]\n",
 741                         crypt_stat->cipher, (int)strlen(crypt_stat->cipher),
 742                         crypt_stat->key_size << 3);
 743         if (crypt_stat->tfm) {
 744                 rc = 0;
 745                 goto out;
 746         }
 747         mutex_lock(&crypt_stat->cs_tfm_mutex);
 748         rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name,
 749                                                     crypt_stat->cipher, "cbc");
 750         if (rc)
 751                 goto out_unlock;
 752         crypt_stat->tfm = crypto_alloc_blkcipher(full_alg_name, 0,
 753                                                  CRYPTO_ALG_ASYNC);
 754         kfree(full_alg_name);
 755         if (IS_ERR(crypt_stat->tfm)) {
 756                 rc = PTR_ERR(crypt_stat->tfm);
 757                 crypt_stat->tfm = NULL;
 758                 ecryptfs_printk(KERN_ERR, "cryptfs: init_crypt_ctx(): "
 759                                 "Error initializing cipher [%s]\n",
 760                                 crypt_stat->cipher);
 761                 goto out_unlock;
 762         }
 763         crypto_blkcipher_set_flags(crypt_stat->tfm, CRYPTO_TFM_REQ_WEAK_KEY);
 764         rc = 0;
 765 out_unlock:
 766         mutex_unlock(&crypt_stat->cs_tfm_mutex);
 767 out:
 768         return rc;
 769 }
 770
 771 static void set_extent_mask_and_shift(struct ecryptfs_crypt_stat *crypt_stat)
 772 {
 773         int extent_size_tmp;
 774
 775         crypt_stat->extent_mask = 0xFFFFFFFF;
 776         crypt_stat->extent_shift = 0;
 777         if (crypt_stat->extent_size == 0)
 778                 return;
 779         extent_size_tmp = crypt_stat->extent_size;
 780         while ((extent_size_tmp & 0x01) == 0) {
 781                 extent_size_tmp >>= 1;
 782                 crypt_stat->extent_mask <<= 1;
 783                 crypt_stat->extent_shift++;
 784         }
 785 }
 786
 787 void ecryptfs_set_default_sizes(struct ecryptfs_crypt_stat *crypt_stat)
 788 {
 789         /* Default values; may be overwritten as we are parsing the
 790          * packets. */
 791         crypt_stat->extent_size = ECRYPTFS_DEFAULT_EXTENT_SIZE;
 792         set_extent_mask_and_shift(crypt_stat);
 793         crypt_stat->iv_bytes = ECRYPTFS_DEFAULT_IV_BYTES;
 794         if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
 795                 crypt_stat->metadata_size = ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
 796         else {
 797                 if (PAGE_CACHE_SIZE <= ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE)
 798                         crypt_stat->metadata_size =
 799                                 ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
 800                 else
 801                         crypt_stat->metadata_size = PAGE_CACHE_SIZE;
 802         }
 803 }
 804
 805 /**
 806  * ecryptfs_compute_root_iv
 807  * @crypt_stats
 808  *
 809  * On error, sets the root IV to all 0's.
 810  */
 811 int ecryptfs_compute_root_iv(struct ecryptfs_crypt_stat *crypt_stat)
 812 {
 813         int rc = 0;
 814         char dst[MD5_DIGEST_SIZE];
 815
 816         BUG_ON(crypt_stat->iv_bytes > MD5_DIGEST_SIZE);
 817         BUG_ON(crypt_stat->iv_bytes <= 0);
 818         if (!(crypt_stat->flags & ECRYPTFS_KEY_VALID)) {
 819                 rc = -EINVAL;
 820                 ecryptfs_printk(KERN_WARNING, "Session key not valid; "
 821                                 "cannot generate root IV\n");
 822                 goto out;
 823         }
 824         rc = ecryptfs_calculate_md5(dst, crypt_stat, crypt_stat->key,
 825                                     crypt_stat->key_size);
 826         if (rc) {
 827                 ecryptfs_printk(KERN_WARNING, "Error attempting to compute "
 828                                 "MD5 while generating root IV\n");
 829                 goto out;
 830         }
 831         memcpy(crypt_stat->root_iv, dst, crypt_stat->iv_bytes);
 832 out:
 833         if (rc) {
 834                 memset(crypt_stat->root_iv, 0, crypt_stat->iv_bytes);
 835                 crypt_stat->flags |= ECRYPTFS_SECURITY_WARNING;
 836         }
 837         return rc;
 838 }
 839
 840 static void ecryptfs_generate_new_key(struct ecryptfs_crypt_stat *crypt_stat)
 841 {
 842         get_random_bytes(crypt_stat->key, crypt_stat->key_size);
 843         crypt_stat->flags |= ECRYPTFS_KEY_VALID;
 844         ecryptfs_compute_root_iv(crypt_stat);
 845         if (unlikely(ecryptfs_verbosity > 0)) {
 846                 ecryptfs_printk(KERN_DEBUG, "Generated new session key:\n");
 847                 ecryptfs_dump_hex(crypt_stat->key,
 848                                   crypt_stat->key_size);
 849         }
 850 }
 851
 852 /**
 853  * ecryptfs_copy_mount_wide_flags_to_inode_flags
 854  * @crypt_stat: The inode's cryptographic context
 855  * @mount_crypt_stat: The mount point's cryptographic context
 856  *
 857  * This function propagates the mount-wide flags to individual inode
 858  * flags.
 859  */
 860 static void ecryptfs_copy_mount_wide_flags_to_inode_flags(
 861         struct ecryptfs_crypt_stat *crypt_stat,
 862         struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
 863 {
 864         if (mount_crypt_stat->flags & ECRYPTFS_XATTR_METADATA_ENABLED)
 865                 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
 866         if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
 867                 crypt_stat->flags |= ECRYPTFS_VIEW_AS_ENCRYPTED;
 868         if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) {
 869                 crypt_stat->flags |= ECRYPTFS_ENCRYPT_FILENAMES;
 870                 if (mount_crypt_stat->flags
 871                     & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK)
 872                         crypt_stat->flags |= ECRYPTFS_ENCFN_USE_MOUNT_FNEK;
 873                 else if (mount_crypt_stat->flags
 874                          & ECRYPTFS_GLOBAL_ENCFN_USE_FEK)
 875                         crypt_stat->flags |= ECRYPTFS_ENCFN_USE_FEK;
 876         }
 877 }
 878
 879 static int ecryptfs_copy_mount_wide_sigs_to_inode_sigs(
 880         struct ecryptfs_crypt_stat *crypt_stat,
 881         struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
 882 {
 883         struct ecryptfs_global_auth_tok *global_auth_tok;
 884         int rc = 0;
 885
 886         mutex_lock(&crypt_stat->keysig_list_mutex);
 887         mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
 888
 889         list_for_each_entry(global_auth_tok,
 890                             &mount_crypt_stat->global_auth_tok_list,
 891                             mount_crypt_stat_list) {
 892                 if (global_auth_tok->flags & ECRYPTFS_AUTH_TOK_FNEK)
 893                         continue;
 894                 rc = ecryptfs_add_keysig(crypt_stat, global_auth_tok->sig);
 895                 if (rc) {
 896                         printk(KERN_ERR "Error adding keysig; rc = [%d]\n", rc);
 897                         goto out;
 898                 }
 899         }
 900
 901 out:
 902         mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
 903         mutex_unlock(&crypt_stat->keysig_list_mutex);
 904         return rc;
 905 }
 906
 907 /**
 908  * ecryptfs_set_default_crypt_stat_vals
 909  * @crypt_stat: The inode's cryptographic context
 910  * @mount_crypt_stat: The mount point's cryptographic context
 911  *
 912  * Default values in the event that policy does not override them.
 913  */
 914 static void ecryptfs_set_default_crypt_stat_vals(
 915         struct ecryptfs_crypt_stat *crypt_stat,
 916         struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
 917 {
 918         ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
 919                                                       mount_crypt_stat);
 920         ecryptfs_set_default_sizes(crypt_stat);
 921         strcpy(crypt_stat->cipher, ECRYPTFS_DEFAULT_CIPHER);
 922         crypt_stat->key_size = ECRYPTFS_DEFAULT_KEY_BYTES;
 923         crypt_stat->flags &= ~(ECRYPTFS_KEY_VALID);
 924         crypt_stat->file_version = ECRYPTFS_FILE_VERSION;
 925         crypt_stat->mount_crypt_stat = mount_crypt_stat;
 926 }
 927
 928 /**
 929  * ecryptfs_new_file_context
 930  * @ecryptfs_dentry: The eCryptfs dentry
 931  *
 932  * If the crypto context for the file has not yet been established,
 933  * this is where we do that.  Establishing a new crypto context
 934  * involves the following decisions:
 935  *  - What cipher to use?
 936  *  - What set of authentication tokens to use?
 937  * Here we just worry about getting enough information into the
 938  * authentication tokens so that we know that they are available.
 939  * We associate the available authentication tokens with the new file
 940  * via the set of signatures in the crypt_stat struct.  Later, when
 941  * the headers are actually written out, we may again defer to
 942  * userspace to perform the encryption of the session key; for the
 943  * foreseeable future, this will be the case with public key packets.
 944  *
 945  * Returns zero on success; non-zero otherwise
 946  */
 947 int ecryptfs_new_file_context(struct dentry *ecryptfs_dentry)
 948 {
 949         struct ecryptfs_crypt_stat *crypt_stat =
 950             &ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat;
 951         struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
 952             &ecryptfs_superblock_to_private(
 953                     ecryptfs_dentry->d_sb)->mount_crypt_stat;
 954         int cipher_name_len;
 955         int rc = 0;
 956
 957         ecryptfs_set_default_crypt_stat_vals(crypt_stat, mount_crypt_stat);
 958         crypt_stat->flags |= (ECRYPTFS_ENCRYPTED | ECRYPTFS_KEY_VALID);
 959         ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
 960                                                       mount_crypt_stat);
 961         rc = ecryptfs_copy_mount_wide_sigs_to_inode_sigs(crypt_stat,
 962                                                          mount_crypt_stat);
 963         if (rc) {
 964                 printk(KERN_ERR "Error attempting to copy mount-wide key sigs "
 965                        "to the inode key sigs; rc = [%d]\n", rc);
 966                 goto out;
 967         }
 968         cipher_name_len =
 969                 strlen(mount_crypt_stat->global_default_cipher_name);
 970         memcpy(crypt_stat->cipher,
 971                mount_crypt_stat->global_default_cipher_name,
 972                cipher_name_len);
 973         crypt_stat->cipher[cipher_name_len] = '\0';
 974         crypt_stat->key_size =
 975                 mount_crypt_stat->global_default_cipher_key_size;
 976         ecryptfs_generate_new_key(crypt_stat);
 977         rc = ecryptfs_init_crypt_ctx(crypt_stat);
 978         if (rc)
 979                 ecryptfs_printk(KERN_ERR, "Error initializing cryptographic "
 980                                 "context for cipher [%s]: rc = [%d]\n",
 981                                 crypt_stat->cipher, rc);
 982 out:
 983         return rc;
 984 }
 985
 986 /**
 987  * ecryptfs_validate_marker - check for the ecryptfs marker
 988  * @data: The data block in which to check
 989  *
 990  * Returns zero if marker found; -EINVAL if not found
 991  */
 992 static int ecryptfs_validate_marker(char *data)
 993 {
 994         u32 m_1, m_2;
 995
 996         m_1 = get_unaligned_be32(data);
 997         m_2 = get_unaligned_be32(data + 4);
 998         if ((m_1 ^ MAGIC_ECRYPTFS_MARKER) == m_2)
 999                 return 0;
1000         ecryptfs_printk(KERN_DEBUG, "m_1 = [0x%.8x]; m_2 = [0x%.8x]; "
1001                         "MAGIC_ECRYPTFS_MARKER = [0x%.8x]\n", m_1, m_2,
1002                         MAGIC_ECRYPTFS_MARKER);
1003         ecryptfs_printk(KERN_DEBUG, "(m_1 ^ MAGIC_ECRYPTFS_MARKER) = "
1004                         "[0x%.8x]\n", (m_1 ^ MAGIC_ECRYPTFS_MARKER));
1005         return -EINVAL;
1006 }
1007
1008 struct ecryptfs_flag_map_elem {
1009         u32 file_flag;
1010         u32 local_flag;
1011 };
1012
1013 /* Add support for additional flags by adding elements here. */
1014 static struct ecryptfs_flag_map_elem ecryptfs_flag_map[] = {
1015         {0x00000001, ECRYPTFS_ENABLE_HMAC},
1016         {0x00000002, ECRYPTFS_ENCRYPTED},
1017         {0x00000004, ECRYPTFS_METADATA_IN_XATTR},
1018         {0x00000008, ECRYPTFS_ENCRYPT_FILENAMES}
1019 };
1020
1021 /**
1022  * ecryptfs_process_flags
1023  * @crypt_stat: The cryptographic context
1024  * @page_virt: Source data to be parsed
1025  * @bytes_read: Updated with the number of bytes read
1026  *
1027  * Returns zero on success; non-zero if the flag set is invalid
1028  */
1029 static int ecryptfs_process_flags(struct ecryptfs_crypt_stat *crypt_stat,
1030                                   char *page_virt, int *bytes_read)
1031 {
1032         int rc = 0;
1033         int i;
1034         u32 flags;
1035
1036         flags = get_unaligned_be32(page_virt);
1037         for (i = 0; i < ((sizeof(ecryptfs_flag_map)
1038                           / sizeof(struct ecryptfs_flag_map_elem))); i++)
1039                 if (flags & ecryptfs_flag_map[i].file_flag) {
1040                         crypt_stat->flags |= ecryptfs_flag_map[i].local_flag;
1041                 } else
1042                         crypt_stat->flags &= ~(ecryptfs_flag_map[i].local_flag);
1043         /* Version is in top 8 bits of the 32-bit flag vector */
1044         crypt_stat->file_version = ((flags >> 24) & 0xFF);
1045         (*bytes_read) = 4;
1046         return rc;
1047 }
1048
1049 /**
1050  * write_ecryptfs_marker
1051  * @page_virt: The pointer to in a page to begin writing the marker
1052  * @written: Number of bytes written
1053  *
1054  * Marker = 0x3c81b7f5
1055  */
1056 static void write_ecryptfs_marker(char *page_virt, size_t *written)
1057 {
1058         u32 m_1, m_2;
1059
1060         get_random_bytes(&m_1, (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2));
1061         m_2 = (m_1 ^ MAGIC_ECRYPTFS_MARKER);
1062         put_unaligned_be32(m_1, page_virt);
1063         page_virt += (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2);
1064         put_unaligned_be32(m_2, page_virt);
1065         (*written) = MAGIC_ECRYPTFS_MARKER_SIZE_BYTES;
1066 }
1067
1068 void ecryptfs_write_crypt_stat_flags(char *page_virt,
1069                                      struct ecryptfs_crypt_stat *crypt_stat,
1070                                      size_t *written)
1071 {
1072         u32 flags = 0;
1073         int i;
1074
1075         for (i = 0; i < ((sizeof(ecryptfs_flag_map)
1076                           / sizeof(struct ecryptfs_flag_map_elem))); i++)
1077                 if (crypt_stat->flags & ecryptfs_flag_map[i].local_flag)
1078                         flags |= ecryptfs_flag_map[i].file_flag;
1079         /* Version is in top 8 bits of the 32-bit flag vector */
1080         flags |= ((((u8)crypt_stat->file_version) << 24) & 0xFF000000);
1081         put_unaligned_be32(flags, page_virt);
1082         (*written) = 4;
1083 }
1084
1085 struct ecryptfs_cipher_code_str_map_elem {
1086         char cipher_str[16];
1087         u8 cipher_code;
1088 };
1089
1090 /* Add support for additional ciphers by adding elements here. The
1091  * cipher_code is whatever OpenPGP applicatoins use to identify the
1092  * ciphers. List in order of probability. */
1093 static struct ecryptfs_cipher_code_str_map_elem
1094 ecryptfs_cipher_code_str_map[] = {
1095         {"aes",RFC2440_CIPHER_AES_128 },
1096         {"blowfish", RFC2440_CIPHER_BLOWFISH},
1097         {"des3_ede", RFC2440_CIPHER_DES3_EDE},
1098         {"cast5", RFC2440_CIPHER_CAST_5},
1099         {"twofish", RFC2440_CIPHER_TWOFISH},
1100         {"cast6", RFC2440_CIPHER_CAST_6},
1101         {"aes", RFC2440_CIPHER_AES_192},
1102         {"aes", RFC2440_CIPHER_AES_256}
1103 };
1104
1105 /**
1106  * ecryptfs_code_for_cipher_string
1107  * @cipher_name: The string alias for the cipher
1108  * @key_bytes: Length of key in bytes; used for AES code selection
1109  *
1110  * Returns zero on no match, or the cipher code on match
1111  */
1112 u8 ecryptfs_code_for_cipher_string(char *cipher_name, size_t key_bytes)
1113 {
1114         int i;
1115         u8 code = 0;
1116         struct ecryptfs_cipher_code_str_map_elem *map =
1117                 ecryptfs_cipher_code_str_map;
1118
1119         if (strcmp(cipher_name, "aes") == 0) {
1120                 switch (key_bytes) {
1121                 case 16:
1122                         code = RFC2440_CIPHER_AES_128;
1123                         break;
1124                 case 24:
1125                         code = RFC2440_CIPHER_AES_192;
1126                         break;
1127                 case 32:
1128                         code = RFC2440_CIPHER_AES_256;
1129                 }
1130         } else {
1131                 for (i = 0; i < ARRAY_SIZE(ecryptfs_cipher_code_str_map); i++)
1132                         if (strcmp(cipher_name, map[i].cipher_str) == 0) {
1133                                 code = map[i].cipher_code;
1134                                 break;
1135                         }
1136         }
1137         return code;
1138 }
1139
1140 /**
1141  * ecryptfs_cipher_code_to_string
1142  * @str: Destination to write out the cipher name
1143  * @cipher_code: The code to convert to cipher name string
1144  *
1145  * Returns zero on success
1146  */
1147 int ecryptfs_cipher_code_to_string(char *str, u8 cipher_code)
1148 {
1149         int rc = 0;
1150         int i;
1151
1152         str[0] = '\0';
1153         for (i = 0; i < ARRAY_SIZE(ecryptfs_cipher_code_str_map); i++)
1154                 if (cipher_code == ecryptfs_cipher_code_str_map[i].cipher_code)
1155                         strcpy(str, ecryptfs_cipher_code_str_map[i].cipher_str);
1156         if (str[0] == '\0') {
1157                 ecryptfs_printk(KERN_WARNING, "Cipher code not recognized: "
1158                                 "[%d]\n", cipher_code);
1159                 rc = -EINVAL;
1160         }
1161         return rc;
1162 }
1163
1164 int ecryptfs_read_and_validate_header_region(struct inode *inode)
1165 {
1166         u8 file_size[ECRYPTFS_SIZE_AND_MARKER_BYTES];
1167         u8 *marker = file_size + ECRYPTFS_FILE_SIZE_BYTES;
1168         int rc;
1169
1170         rc = ecryptfs_read_lower(file_size, 0, ECRYPTFS_SIZE_AND_MARKER_BYTES,
1171                                  inode);
1172         if (rc < ECRYPTFS_SIZE_AND_MARKER_BYTES)
1173                 return rc >= 0 ? -EINVAL : rc;
1174         rc = ecryptfs_validate_marker(marker);
1175         if (!rc)
1176                 ecryptfs_i_size_init(file_size, inode);
1177         return rc;
1178 }
1179
1180 void
1181 ecryptfs_write_header_metadata(char *virt,
1182                                struct ecryptfs_crypt_stat *crypt_stat,
1183                                size_t *written)
1184 {
1185         u32 header_extent_size;
1186         u16 num_header_extents_at_front;
1187
1188         header_extent_size = (u32)crypt_stat->extent_size;
1189         num_header_extents_at_front =
1190                 (u16)(crypt_stat->metadata_size / crypt_stat->extent_size);
1191         put_unaligned_be32(header_extent_size, virt);
1192         virt += 4;
1193         put_unaligned_be16(num_header_extents_at_front, virt);
1194         (*written) = 6;
1195 }
1196
1197 struct kmem_cache *ecryptfs_header_cache;
1198
1199 /**
1200  * ecryptfs_write_headers_virt
1201  * @page_virt: The virtual address to write the headers to
1202  * @max: The size of memory allocated at page_virt
1203  * @size: Set to the number of bytes written by this function
1204  * @crypt_stat: The cryptographic context
1205  * @ecryptfs_dentry: The eCryptfs dentry
1206  *
1207  * Format version: 1
1208  *
1209  *   Header Extent:
1210  *     Octets 0-7:        Unencrypted file size (big-endian)
1211  *     Octets 8-15:       eCryptfs special marker
1212  *     Octets 16-19:      Flags
1213  *      Octet 16:         File format version number (between 0 and 255)
1214  *      Octets 17-18:     Reserved
1215  *      Octet 19:         Bit 1 (lsb): Reserved
1216  *                        Bit 2: Encrypted?
1217  *                        Bits 3-8: Reserved
1218  *     Octets 20-23:      Header extent size (big-endian)
1219  *     Octets 24-25:      Number of header extents at front of file
1220  *                        (big-endian)
1221  *     Octet  26:         Begin RFC 2440 authentication token packet set
1222  *   Data Extent 0:
1223  *     Lower data (CBC encrypted)
1224  *   Data Extent 1:
1225  *     Lower data (CBC encrypted)
1226  *   ...
1227  *
1228  * Returns zero on success
1229  */
1230 static int ecryptfs_write_headers_virt(char *page_virt, size_t max,
1231                                        size_t *size,
1232                                        struct ecryptfs_crypt_stat *crypt_stat,
1233                                        struct dentry *ecryptfs_dentry)
1234 {
1235         int rc;
1236         size_t written;
1237         size_t offset;
1238
1239         offset = ECRYPTFS_FILE_SIZE_BYTES;
1240         write_ecryptfs_marker((page_virt + offset), &written);
1241         offset += written;
1242         ecryptfs_write_crypt_stat_flags((page_virt + offset), crypt_stat,
1243                                         &written);
1244         offset += written;
1245         ecryptfs_write_header_metadata((page_virt + offset), crypt_stat,
1246                                        &written);
1247         offset += written;
1248         rc = ecryptfs_generate_key_packet_set((page_virt + offset), crypt_stat,
1249                                               ecryptfs_dentry, &written,
1250                                               max - offset);
1251         if (rc)
1252                 ecryptfs_printk(KERN_WARNING, "Error generating key packet "
1253                                 "set; rc = [%d]\n", rc);
1254         if (size) {
1255                 offset += written;
1256                 *size = offset;
1257         }
1258         return rc;
1259 }
1260
1261 static int
1262 ecryptfs_write_metadata_to_contents(struct dentry *ecryptfs_dentry,
1263                                     char *virt, size_t virt_len)
1264 {
1265         int rc;
1266
1267         rc = ecryptfs_write_lower(ecryptfs_dentry->d_inode, virt,
1268                                   0, virt_len);
1269         if (rc < 0)
1270                 printk(KERN_ERR "%s: Error attempting to write header "
1271                        "information to lower file; rc = [%d]\n", __func__, rc);
1272         else
1273                 rc = 0;
1274         return rc;
1275 }
1276
1277 static int
1278 ecryptfs_write_metadata_to_xattr(struct dentry *ecryptfs_dentry,
1279                                  char *page_virt, size_t size)
1280 {
1281         int rc;
1282
1283         rc = ecryptfs_setxattr(ecryptfs_dentry, ECRYPTFS_XATTR_NAME, page_virt,
1284                                size, 0);
1285         return rc;
1286 }
1287
1288 static unsigned long ecryptfs_get_zeroed_pages(gfp_t gfp_mask,
1289                                                unsigned int order)
1290 {
1291         struct page *page;
1292
1293         page = alloc_pages(gfp_mask | __GFP_ZERO, order);
1294         if (page)
1295                 return (unsigned long) page_address(page);
1296         return 0;
1297 }
1298
1299 /**
1300  * ecryptfs_write_metadata
1301  * @ecryptfs_dentry: The eCryptfs dentry
1302  *
1303  * Write the file headers out.  This will likely involve a userspace
1304  * callout, in which the session key is encrypted with one or more
1305  * public keys and/or the passphrase necessary to do the encryption is
1306  * retrieved via a prompt.  Exactly what happens at this point should
1307  * be policy-dependent.
1308  *
1309  * Returns zero on success; non-zero on error
1310  */
1311 int ecryptfs_write_metadata(struct dentry *ecryptfs_dentry)
1312 {
1313         struct ecryptfs_crypt_stat *crypt_stat =
1314                 &ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat;
1315         unsigned int order;
1316         char *virt;
1317         size_t virt_len;
1318         size_t size = 0;
1319         int rc = 0;
1320
1321         if (likely(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
1322                 if (!(crypt_stat->flags & ECRYPTFS_KEY_VALID)) {
1323                         printk(KERN_ERR "Key is invalid; bailing out\n");
1324                         rc = -EINVAL;
1325                         goto out;
1326                 }
1327         } else {
1328                 printk(KERN_WARNING "%s: Encrypted flag not set\n",
1329                        __func__);
1330                 rc = -EINVAL;
1331                 goto out;
1332         }
1333         virt_len = crypt_stat->metadata_size;
1334         order = get_order(virt_len);
1335         /* Released in this function */
1336         virt = (char *)ecryptfs_get_zeroed_pages(GFP_KERNEL, order);
1337         if (!virt) {
1338                 printk(KERN_ERR "%s: Out of memory\n", __func__);
1339                 rc = -ENOMEM;
1340                 goto out;
1341         }
1342         /* Zeroed page ensures the in-header unencrypted i_size is set to 0 */
1343         rc = ecryptfs_write_headers_virt(virt, virt_len, &size, crypt_stat,
1344                                          ecryptfs_dentry);
1345         if (unlikely(rc)) {
1346                 printk(KERN_ERR "%s: Error whilst writing headers; rc = [%d]\n",
1347                        __func__, rc);
1348                 goto out_free;
1349         }
1350         if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
1351                 rc = ecryptfs_write_metadata_to_xattr(ecryptfs_dentry, virt,
1352                                                       size);
1353         else
1354                 rc = ecryptfs_write_metadata_to_contents(ecryptfs_dentry, virt,
1355                                                          virt_len);
1356         if (rc) {
1357                 printk(KERN_ERR "%s: Error writing metadata out to lower file; "
1358                        "rc = [%d]\n", __func__, rc);
1359                 goto out_free;
1360         }
1361 out_free:
1362         free_pages((unsigned long)virt, order);
1363 out:
1364         return rc;
1365 }
1366
1367 #define ECRYPTFS_DONT_VALIDATE_HEADER_SIZE 0
1368 #define ECRYPTFS_VALIDATE_HEADER_SIZE 1
1369 static int parse_header_metadata(struct ecryptfs_crypt_stat *crypt_stat,
1370                                  char *virt, int *bytes_read,
1371                                  int validate_header_size)
1372 {
1373         int rc = 0;
1374         u32 header_extent_size;
1375         u16 num_header_extents_at_front;
1376
1377         header_extent_size = get_unaligned_be32(virt);
1378         virt += sizeof(__be32);
1379         num_header_extents_at_front = get_unaligned_be16(virt);
1380         crypt_stat->metadata_size = (((size_t)num_header_extents_at_front
1381                                      * (size_t)header_extent_size));
1382         (*bytes_read) = (sizeof(__be32) + sizeof(__be16));
1383         if ((validate_header_size == ECRYPTFS_VALIDATE_HEADER_SIZE)
1384             && (crypt_stat->metadata_size
1385                 < ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE)) {
1386                 rc = -EINVAL;
1387                 printk(KERN_WARNING "Invalid header size: [%zd]\n",
1388                        crypt_stat->metadata_size);
1389         }
1390         return rc;
1391 }
1392
1393 /**
1394  * set_default_header_data
1395  * @crypt_stat: The cryptographic context
1396  *
1397  * For version 0 file format; this function is only for backwards
1398  * compatibility for files created with the prior versions of
1399  * eCryptfs.
1400  */
1401 static void set_default_header_data(struct ecryptfs_crypt_stat *crypt_stat)
1402 {
1403         crypt_stat->metadata_size = ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
1404 }
1405
1406 void ecryptfs_i_size_init(const char *page_virt, struct inode *inode)
1407 {
1408         struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
1409         struct ecryptfs_crypt_stat *crypt_stat;
1410         u64 file_size;
1411
1412         crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
1413         mount_crypt_stat =
1414                 &ecryptfs_superblock_to_private(inode->i_sb)->mount_crypt_stat;
1415         if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED) {
1416                 file_size = i_size_read(ecryptfs_inode_to_lower(inode));
1417                 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
1418                         file_size += crypt_stat->metadata_size;
1419         } else
1420                 file_size = get_unaligned_be64(page_virt);
1421         i_size_write(inode, (loff_t)file_size);
1422         crypt_stat->flags |= ECRYPTFS_I_SIZE_INITIALIZED;
1423 }
1424
1425 /**
1426  * ecryptfs_read_headers_virt
1427  * @page_virt: The virtual address into which to read the headers
1428  * @crypt_stat: The cryptographic context
1429  * @ecryptfs_dentry: The eCryptfs dentry
1430  * @validate_header_size: Whether to validate the header size while reading
1431  *
1432  * Read/parse the header data. The header format is detailed in the
1433  * comment block for the ecryptfs_write_headers_virt() function.
1434  *
1435  * Returns zero on success
1436  */
1437 static int ecryptfs_read_headers_virt(char *page_virt,
1438                                       struct ecryptfs_crypt_stat *crypt_stat,
1439                                       struct dentry *ecryptfs_dentry,
1440                                       int validate_header_size)
1441 {
1442         int rc = 0;
1443         int offset;
1444         int bytes_read;
1445
1446         ecryptfs_set_default_sizes(crypt_stat);
1447         crypt_stat->mount_crypt_stat = &ecryptfs_superblock_to_private(
1448                 ecryptfs_dentry->d_sb)->mount_crypt_stat;
1449         offset = ECRYPTFS_FILE_SIZE_BYTES;
1450         rc = ecryptfs_validate_marker(page_virt + offset);
1451         if (rc)
1452                 goto out;
1453         if (!(crypt_stat->flags & ECRYPTFS_I_SIZE_INITIALIZED))
1454                 ecryptfs_i_size_init(page_virt, ecryptfs_dentry->d_inode);
1455         offset += MAGIC_ECRYPTFS_MARKER_SIZE_BYTES;
1456         rc = ecryptfs_process_flags(crypt_stat, (page_virt + offset),
1457                                     &bytes_read);
1458         if (rc) {
1459                 ecryptfs_printk(KERN_WARNING, "Error processing flags\n");
1460                 goto out;
1461         }
1462         if (crypt_stat->file_version > ECRYPTFS_SUPPORTED_FILE_VERSION) {
1463                 ecryptfs_printk(KERN_WARNING, "File version is [%d]; only "
1464                                 "file version [%d] is supported by this "
1465                                 "version of eCryptfs\n",
1466                                 crypt_stat->file_version,
1467                                 ECRYPTFS_SUPPORTED_FILE_VERSION);
1468                 rc = -EINVAL;
1469                 goto out;
1470         }
1471         offset += bytes_read;
1472         if (crypt_stat->file_version >= 1) {
1473                 rc = parse_header_metadata(crypt_stat, (page_virt + offset),
1474                                            &bytes_read, validate_header_size);
1475                 if (rc) {
1476                         ecryptfs_printk(KERN_WARNING, "Error reading header "
1477                                         "metadata; rc = [%d]\n", rc);
1478                 }
1479                 offset += bytes_read;
1480         } else
1481                 set_default_header_data(crypt_stat);
1482         rc = ecryptfs_parse_packet_set(crypt_stat, (page_virt + offset),
1483                                        ecryptfs_dentry);
1484 out:
1485         return rc;
1486 }
1487
1488 /**
1489  * ecryptfs_read_xattr_region
1490  * @page_virt: The vitual address into which to read the xattr data
1491  * @ecryptfs_inode: The eCryptfs inode
1492  *
1493  * Attempts to read the crypto metadata from the extended attribute
1494  * region of the lower file.
1495  *
1496  * Returns zero on success; non-zero on error
1497  */
1498 int ecryptfs_read_xattr_region(char *page_virt, struct inode *ecryptfs_inode)
1499 {
1500         struct dentry *lower_dentry =
1501                 ecryptfs_inode_to_private(ecryptfs_inode)->lower_file->f_dentry;
1502         ssize_t size;
1503         int rc = 0;
1504
1505         size = ecryptfs_getxattr_lower(lower_dentry, ECRYPTFS_XATTR_NAME,
1506                                        page_virt, ECRYPTFS_DEFAULT_EXTENT_SIZE);
1507         if (size < 0) {
1508                 if (unlikely(ecryptfs_verbosity > 0))
1509                         printk(KERN_INFO "Error attempting to read the [%s] "
1510                                "xattr from the lower file; return value = "
1511                                "[%zd]\n", ECRYPTFS_XATTR_NAME, size);
1512                 rc = -EINVAL;
1513                 goto out;
1514         }
1515 out:
1516         return rc;
1517 }
1518
1519 int ecryptfs_read_and_validate_xattr_region(struct dentry *dentry,
1520                                             struct inode *inode)
1521 {
1522         u8 file_size[ECRYPTFS_SIZE_AND_MARKER_BYTES];
1523         u8 *marker = file_size + ECRYPTFS_FILE_SIZE_BYTES;
1524         int rc;
1525
1526         rc = ecryptfs_getxattr_lower(ecryptfs_dentry_to_lower(dentry),
1527                                      ECRYPTFS_XATTR_NAME, file_size,
1528                                      ECRYPTFS_SIZE_AND_MARKER_BYTES);
1529         if (rc < ECRYPTFS_SIZE_AND_MARKER_BYTES)
1530                 return rc >= 0 ? -EINVAL : rc;
1531         rc = ecryptfs_validate_marker(marker);
1532         if (!rc)
1533                 ecryptfs_i_size_init(file_size, inode);
1534         return rc;
1535 }
1536
1537 /**
1538  * ecryptfs_read_metadata
1539  *
1540  * Common entry point for reading file metadata. From here, we could
1541  * retrieve the header information from the header region of the file,
1542  * the xattr region of the file, or some other repostory that is
1543  * stored separately from the file itself. The current implementation
1544  * supports retrieving the metadata information from the file contents
1545  * and from the xattr region.
1546  *
1547  * Returns zero if valid headers found and parsed; non-zero otherwise
1548  */
1549 int ecryptfs_read_metadata(struct dentry *ecryptfs_dentry)
1550 {
1551         int rc = 0;
1552         char *page_virt = NULL;
1553         struct inode *ecryptfs_inode = ecryptfs_dentry->d_inode;
1554         struct ecryptfs_crypt_stat *crypt_stat =
1555             &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
1556         struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
1557                 &ecryptfs_superblock_to_private(
1558                         ecryptfs_dentry->d_sb)->mount_crypt_stat;
1559
1560         ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
1561                                                       mount_crypt_stat);
1562         /* Read the first page from the underlying file */
1563         page_virt = kmem_cache_alloc(ecryptfs_header_cache, GFP_USER);
1564         if (!page_virt) {
1565                 rc = -ENOMEM;
1566                 printk(KERN_ERR "%s: Unable to allocate page_virt\n",
1567                        __func__);
1568                 goto out;
1569         }
1570         rc = ecryptfs_read_lower(page_virt, 0, crypt_stat->extent_size,
1571                                  ecryptfs_inode);
1572         if (rc >= 0)
1573                 rc = ecryptfs_read_headers_virt(page_virt, crypt_stat,
1574                                                 ecryptfs_dentry,
1575                                                 ECRYPTFS_VALIDATE_HEADER_SIZE);
1576         if (rc) {
1577                 memset(page_virt, 0, PAGE_CACHE_SIZE);
1578                 rc = ecryptfs_read_xattr_region(page_virt, ecryptfs_inode);
1579                 if (rc) {
1580                         printk(KERN_DEBUG "Valid eCryptfs headers not found in "
1581                                "file header region or xattr region, inode %lu\n",
1582                                 ecryptfs_inode->i_ino);
1583                         rc = -EINVAL;
1584                         goto out;
1585                 }
1586                 rc = ecryptfs_read_headers_virt(page_virt, crypt_stat,
1587                                                 ecryptfs_dentry,
1588                                                 ECRYPTFS_DONT_VALIDATE_HEADER_SIZE);
1589                 if (rc) {
1590                         printk(KERN_DEBUG "Valid eCryptfs headers not found in "
1591                                "file xattr region either, inode %lu\n",
1592                                 ecryptfs_inode->i_ino);
1593                         rc = -EINVAL;
1594                 }
1595                 if (crypt_stat->mount_crypt_stat->flags
1596                     & ECRYPTFS_XATTR_METADATA_ENABLED) {
1597                         crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
1598                 } else {
1599                         printk(KERN_WARNING "Attempt to access file with "
1600                                "crypto metadata only in the extended attribute "
1601                                "region, but eCryptfs was mounted without "
1602                                "xattr support enabled. eCryptfs will not treat "
1603                                "this like an encrypted file, inode %lu\n",
1604                                 ecryptfs_inode->i_ino);
1605                         rc = -EINVAL;
1606                 }
1607         }
1608 out:
1609         if (page_virt) {
1610                 memset(page_virt, 0, PAGE_CACHE_SIZE);
1611                 kmem_cache_free(ecryptfs_header_cache, page_virt);
1612         }
1613         return rc;
1614 }
1615
1616 /**
1617  * ecryptfs_encrypt_filename - encrypt filename
1618  *
1619  * CBC-encrypts the filename. We do not want to encrypt the same
1620  * filename with the same key and IV, which may happen with hard
1621  * links, so we prepend random bits to each filename.
1622  *
1623  * Returns zero on success; non-zero otherwise
1624  */
1625 static int
1626 ecryptfs_encrypt_filename(struct ecryptfs_filename *filename,
1627                           struct ecryptfs_crypt_stat *crypt_stat,
1628                           struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
1629 {
1630         int rc = 0;
1631
1632         filename->encrypted_filename = NULL;
1633         filename->encrypted_filename_size = 0;
1634         if ((crypt_stat && (crypt_stat->flags & ECRYPTFS_ENCFN_USE_MOUNT_FNEK))
1635             || (mount_crypt_stat && (mount_crypt_stat->flags
1636                                      & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK))) {
1637                 size_t packet_size;
1638                 size_t remaining_bytes;
1639
1640                 rc = ecryptfs_write_tag_70_packet(
1641                         NULL, NULL,
1642                         &filename->encrypted_filename_size,
1643                         mount_crypt_stat, NULL,
1644                         filename->filename_size);
1645                 if (rc) {
1646                         printk(KERN_ERR "%s: Error attempting to get packet "
1647                                "size for tag 72; rc = [%d]\n", __func__,
1648                                rc);
1649                         filename->encrypted_filename_size = 0;
1650                         goto out;
1651                 }
1652                 filename->encrypted_filename =
1653                         kmalloc(filename->encrypted_filename_size, GFP_KERNEL);
1654                 if (!filename->encrypted_filename) {
1655                         printk(KERN_ERR "%s: Out of memory whilst attempting "
1656                                "to kmalloc [%zd] bytes\n", __func__,
1657                                filename->encrypted_filename_size);
1658                         rc = -ENOMEM;
1659                         goto out;
1660                 }
1661                 remaining_bytes = filename->encrypted_filename_size;
1662                 rc = ecryptfs_write_tag_70_packet(filename->encrypted_filename,
1663                                                   &remaining_bytes,
1664                                                   &packet_size,
1665                                                   mount_crypt_stat,
1666                                                   filename->filename,
1667                                                   filename->filename_size);
1668                 if (rc) {
1669                         printk(KERN_ERR "%s: Error attempting to generate "
1670                                "tag 70 packet; rc = [%d]\n", __func__,
1671                                rc);
1672                         kfree(filename->encrypted_filename);
1673                         filename->encrypted_filename = NULL;
1674                         filename->encrypted_filename_size = 0;
1675                         goto out;
1676                 }
1677                 filename->encrypted_filename_size = packet_size;
1678         } else {
1679                 printk(KERN_ERR "%s: No support for requested filename "
1680                        "encryption method in this release\n", __func__);
1681                 rc = -EOPNOTSUPP;
1682                 goto out;
1683         }
1684 out:
1685         return rc;
1686 }
1687
1688 static int ecryptfs_copy_filename(char **copied_name, size_t *copied_name_size,
1689                                   const char *name, size_t name_size)
1690 {
1691         int rc = 0;
1692
1693         (*copied_name) = kmalloc((name_size + 1), GFP_KERNEL);
1694         if (!(*copied_name)) {
1695                 rc = -ENOMEM;
1696                 goto out;
1697         }
1698         memcpy((void *)(*copied_name), (void *)name, name_size);
1699         (*copied_name)[(name_size)] = '\0';     /* Only for convenience
1700                                                  * in printing out the
1701                                                  * string in debug
1702                                                  * messages */
1703         (*copied_name_size) = name_size;
1704 out:
1705         return rc;
1706 }
1707
1708 /**
1709  * ecryptfs_process_key_cipher - Perform key cipher initialization.
1710  * @key_tfm: Crypto context for key material, set by this function
1711  * @cipher_name: Name of the cipher
1712  * @key_size: Size of the key in bytes
1713  *
1714  * Returns zero on success. Any crypto_tfm structs allocated here
1715  * should be released by other functions, such as on a superblock put
1716  * event, regardless of whether this function succeeds for fails.
1717  */
1718 static int
1719 ecryptfs_process_key_cipher(struct crypto_blkcipher **key_tfm,
1720                             char *cipher_name, size_t *key_size)
1721 {
1722         char dummy_key[ECRYPTFS_MAX_KEY_BYTES];
1723         char *full_alg_name = NULL;
1724         int rc;
1725
1726         *key_tfm = NULL;
1727         if (*key_size > ECRYPTFS_MAX_KEY_BYTES) {
1728                 rc = -EINVAL;
1729                 printk(KERN_ERR "Requested key size is [%zd] bytes; maximum "
1730                       "allowable is [%d]\n", *key_size, ECRYPTFS_MAX_KEY_BYTES);
1731                 goto out;
1732         }
1733         rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name, cipher_name,
1734                                                     "ecb");
1735         if (rc)
1736                 goto out;
1737         *key_tfm = crypto_alloc_blkcipher(full_alg_name, 0, CRYPTO_ALG_ASYNC);
1738         if (IS_ERR(*key_tfm)) {
1739                 rc = PTR_ERR(*key_tfm);
1740                 printk(KERN_ERR "Unable to allocate crypto cipher with name "
1741                        "[%s]; rc = [%d]\n", full_alg_name, rc);
1742                 goto out;
1743         }
1744         crypto_blkcipher_set_flags(*key_tfm, CRYPTO_TFM_REQ_WEAK_KEY);
1745         if (*key_size == 0) {
1746                 struct blkcipher_alg *alg = crypto_blkcipher_alg(*key_tfm);
1747
1748                 *key_size = alg->max_keysize;
1749         }
1750         get_random_bytes(dummy_key, *key_size);
1751         rc = crypto_blkcipher_setkey(*key_tfm, dummy_key, *key_size);
1752         if (rc) {
1753                 printk(KERN_ERR "Error attempting to set key of size [%zd] for "
1754                        "cipher [%s]; rc = [%d]\n", *key_size, full_alg_name,
1755                        rc);
1756                 rc = -EINVAL;
1757                 goto out;
1758         }
1759 out:
1760         kfree(full_alg_name);
1761         return rc;
1762 }
1763
1764 struct kmem_cache *ecryptfs_key_tfm_cache;
1765 static struct list_head key_tfm_list;
1766 struct mutex key_tfm_list_mutex;
1767
1768 int __init ecryptfs_init_crypto(void)
1769 {
1770         mutex_init(&key_tfm_list_mutex);
1771         INIT_LIST_HEAD(&key_tfm_list);
1772         return 0;
1773 }
1774
1775 /**
1776  * ecryptfs_destroy_crypto - free all cached key_tfms on key_tfm_list
1777  *
1778  * Called only at module unload time
1779  */
1780 int ecryptfs_destroy_crypto(void)
1781 {
1782         struct ecryptfs_key_tfm *key_tfm, *key_tfm_tmp;
1783
1784         mutex_lock(&key_tfm_list_mutex);
1785         list_for_each_entry_safe(key_tfm, key_tfm_tmp, &key_tfm_list,
1786                                  key_tfm_list) {
1787                 list_del(&key_tfm->key_tfm_list);
1788                 if (key_tfm->key_tfm)
1789                         crypto_free_blkcipher(key_tfm->key_tfm);
1790                 kmem_cache_free(ecryptfs_key_tfm_cache, key_tfm);
1791         }
1792         mutex_unlock(&key_tfm_list_mutex);
1793         return 0;
1794 }
1795
1796 int
1797 ecryptfs_add_new_key_tfm(struct ecryptfs_key_tfm **key_tfm, char *cipher_name,
1798                          size_t key_size)
1799 {
1800         struct ecryptfs_key_tfm *tmp_tfm;
1801         int rc = 0;
1802
1803         BUG_ON(!mutex_is_locked(&key_tfm_list_mutex));
1804
1805         tmp_tfm = kmem_cache_alloc(ecryptfs_key_tfm_cache, GFP_KERNEL);
1806         if (key_tfm != NULL)
1807                 (*key_tfm) = tmp_tfm;
1808         if (!tmp_tfm) {
1809                 rc = -ENOMEM;
1810                 printk(KERN_ERR "Error attempting to allocate from "
1811                        "ecryptfs_key_tfm_cache\n");
1812                 goto out;
1813         }
1814         mutex_init(&tmp_tfm->key_tfm_mutex);
1815         strncpy(tmp_tfm->cipher_name, cipher_name,
1816                 ECRYPTFS_MAX_CIPHER_NAME_SIZE);
1817         tmp_tfm->cipher_name[ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
1818         tmp_tfm->key_size = key_size;
1819         rc = ecryptfs_process_key_cipher(&tmp_tfm->key_tfm,
1820                                          tmp_tfm->cipher_name,
1821                                          &tmp_tfm->key_size);
1822         if (rc) {
1823                 printk(KERN_ERR "Error attempting to initialize key TFM "
1824                        "cipher with name = [%s]; rc = [%d]\n",
1825                        tmp_tfm->cipher_name, rc);
1826                 kmem_cache_free(ecryptfs_key_tfm_cache, tmp_tfm);
1827                 if (key_tfm != NULL)
1828                         (*key_tfm) = NULL;
1829                 goto out;
1830         }
1831         list_add(&tmp_tfm->key_tfm_list, &key_tfm_list);
1832 out:
1833         return rc;
1834 }
1835
1836 /**
1837  * ecryptfs_tfm_exists - Search for existing tfm for cipher_name.
1838  * @cipher_name: the name of the cipher to search for
1839  * @key_tfm: set to corresponding tfm if found
1840  *
1841  * Searches for cached key_tfm matching @cipher_name
1842  * Must be called with &key_tfm_list_mutex held
1843  * Returns 1 if found, with @key_tfm set
1844  * Returns 0 if not found, with @key_tfm set to NULL
1845  */
1846 int ecryptfs_tfm_exists(char *cipher_name, struct ecryptfs_key_tfm **key_tfm)
1847 {
1848         struct ecryptfs_key_tfm *tmp_key_tfm;
1849
1850         BUG_ON(!mutex_is_locked(&key_tfm_list_mutex));
1851
1852         list_for_each_entry(tmp_key_tfm, &key_tfm_list, key_tfm_list) {
1853                 if (strcmp(tmp_key_tfm->cipher_name, cipher_name) == 0) {
1854                         if (key_tfm)
1855                                 (*key_tfm) = tmp_key_tfm;
1856                         return 1;
1857                 }
1858         }
1859         if (key_tfm)
1860                 (*key_tfm) = NULL;
1861         return 0;
1862 }
1863
1864 /**
1865  * ecryptfs_get_tfm_and_mutex_for_cipher_name
1866  *
1867  * @tfm: set to cached tfm found, or new tfm created
1868  * @tfm_mutex: set to mutex for cached tfm found, or new tfm created
1869  * @cipher_name: the name of the cipher to search for and/or add
1870  *
1871  * Sets pointers to @tfm & @tfm_mutex matching @cipher_name.
1872  * Searches for cached item first, and creates new if not found.
1873  * Returns 0 on success, non-zero if adding new cipher failed
1874  */
1875 int ecryptfs_get_tfm_and_mutex_for_cipher_name(struct crypto_blkcipher **tfm,
1876                                                struct mutex **tfm_mutex,
1877                                                char *cipher_name)
1878 {
1879         struct ecryptfs_key_tfm *key_tfm;
1880         int rc = 0;
1881
1882         (*tfm) = NULL;
1883         (*tfm_mutex) = NULL;
1884
1885         mutex_lock(&key_tfm_list_mutex);
1886         if (!ecryptfs_tfm_exists(cipher_name, &key_tfm)) {
1887                 rc = ecryptfs_add_new_key_tfm(&key_tfm, cipher_name, 0);
1888                 if (rc) {
1889                         printk(KERN_ERR "Error adding new key_tfm to list; "
1890                                         "rc = [%d]\n", rc);
1891                         goto out;
1892                 }
1893         }
1894         (*tfm) = key_tfm->key_tfm;
1895         (*tfm_mutex) = &key_tfm->key_tfm_mutex;
1896 out:
1897         mutex_unlock(&key_tfm_list_mutex);
1898         return rc;
1899 }
1900
1901 /* 64 characters forming a 6-bit target field */
1902 static unsigned char *portable_filename_chars = ("-.0123456789ABCD"
1903                                                  "EFGHIJKLMNOPQRST"
1904                                                  "UVWXYZabcdefghij"
1905                                                  "klmnopqrstuvwxyz");
1906
1907 /* We could either offset on every reverse map or just pad some 0x00's
1908  * at the front here */
1909 static const unsigned char filename_rev_map[256] = {
1910         0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 7 */
1911         0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 15 */
1912         0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 23 */
1913         0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 31 */
1914         0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 39 */
1915         0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, /* 47 */
1916         0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, /* 55 */
1917         0x0A, 0x0B, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 63 */
1918         0x00, 0x0C, 0x0D, 0x0E, 0x0F, 0x10, 0x11, 0x12, /* 71 */
1919         0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1A, /* 79 */
1920         0x1B, 0x1C, 0x1D, 0x1E, 0x1F, 0x20, 0x21, 0x22, /* 87 */
1921         0x23, 0x24, 0x25, 0x00, 0x00, 0x00, 0x00, 0x00, /* 95 */
1922         0x00, 0x26, 0x27, 0x28, 0x29, 0x2A, 0x2B, 0x2C, /* 103 */
1923         0x2D, 0x2E, 0x2F, 0x30, 0x31, 0x32, 0x33, 0x34, /* 111 */
1924         0x35, 0x36, 0x37, 0x38, 0x39, 0x3A, 0x3B, 0x3C, /* 119 */
1925         0x3D, 0x3E, 0x3F /* 123 - 255 initialized to 0x00 */
1926 };
1927
1928 /**
1929  * ecryptfs_encode_for_filename
1930  * @dst: Destination location for encoded filename
1931  * @dst_size: Size of the encoded filename in bytes
1932  * @src: Source location for the filename to encode
1933  * @src_size: Size of the source in bytes
1934  */
1935 void ecryptfs_encode_for_filename(unsigned char *dst, size_t *dst_size,
1936                                   unsigned char *src, size_t src_size)
1937 {
1938         size_t num_blocks;
1939         size_t block_num = 0;
1940         size_t dst_offset = 0;
1941         unsigned char last_block[3];
1942
1943         if (src_size == 0) {
1944                 (*dst_size) = 0;
1945                 goto out;
1946         }
1947         num_blocks = (src_size / 3);
1948         if ((src_size % 3) == 0) {
1949                 memcpy(last_block, (&src[src_size - 3]), 3);
1950         } else {
1951                 num_blocks++;
1952                 last_block[2] = 0x00;
1953                 switch (src_size % 3) {
1954                 case 1:
1955                         last_block[0] = src[src_size - 1];
1956                         last_block[1] = 0x00;
1957                         break;
1958                 case 2:
1959                         last_block[0] = src[src_size - 2];
1960                         last_block[1] = src[src_size - 1];
1961                 }
1962         }
1963         (*dst_size) = (num_blocks * 4);
1964         if (!dst)
1965                 goto out;
1966         while (block_num < num_blocks) {
1967                 unsigned char *src_block;
1968                 unsigned char dst_block[4];
1969
1970                 if (block_num == (num_blocks - 1))
1971                         src_block = last_block;
1972                 else
1973                         src_block = &src[block_num * 3];
1974                 dst_block[0] = ((src_block[0] >> 2) & 0x3F);
1975                 dst_block[1] = (((src_block[0] << 4) & 0x30)
1976                                 | ((src_block[1] >> 4) & 0x0F));
1977                 dst_block[2] = (((src_block[1] << 2) & 0x3C)
1978                                 | ((src_block[2] >> 6) & 0x03));
1979                 dst_block[3] = (src_block[2] & 0x3F);
1980                 dst[dst_offset++] = portable_filename_chars[dst_block[0]];
1981                 dst[dst_offset++] = portable_filename_chars[dst_block[1]];
1982                 dst[dst_offset++] = portable_filename_chars[dst_block[2]];
1983                 dst[dst_offset++] = portable_filename_chars[dst_block[3]];
1984                 block_num++;
1985         }
1986 out:
1987         return;
1988 }
1989
1990 /**
1991  * ecryptfs_decode_from_filename
1992  * @dst: If NULL, this function only sets @dst_size and returns. If
1993  *       non-NULL, this function decodes the encoded octets in @src
1994  *       into the memory that @dst points to.
1995  * @dst_size: Set to the size of the decoded string.
1996  * @src: The encoded set of octets to decode.
1997  * @src_size: The size of the encoded set of octets to decode.
1998  */
1999 static void
2000 ecryptfs_decode_from_filename(unsigned char *dst, size_t *dst_size,
2001                               const unsigned char *src, size_t src_size)
2002 {
2003         u8 current_bit_offset = 0;
2004         size_t src_byte_offset = 0;
2005         size_t dst_byte_offset = 0;
2006
2007         if (dst == NULL) {
2008                 /* Not exact; conservatively long. Every block of 4
2009                  * encoded characters decodes into a block of 3
2010                  * decoded characters. This segment of code provides
2011                  * the caller with the maximum amount of allocated
2012                  * space that @dst will need to point to in a
2013                  * subsequent call. */
2014                 (*dst_size) = (((src_size + 1) * 3) / 4);
2015                 goto out;
2016         }
2017         while (src_byte_offset < src_size) {
2018                 unsigned char src_byte =
2019                                 filename_rev_map[(int)src[src_byte_offset]];
2020
2021                 switch (current_bit_offset) {
2022                 case 0:
2023                         dst[dst_byte_offset] = (src_byte << 2);
2024                         current_bit_offset = 6;
2025                         break;
2026                 case 6:
2027                         dst[dst_byte_offset++] |= (src_byte >> 4);
2028                         dst[dst_byte_offset] = ((src_byte & 0xF)
2029                                                  << 4);
2030                         current_bit_offset = 4;
2031                         break;
2032                 case 4:
2033                         dst[dst_byte_offset++] |= (src_byte >> 2);
2034                         dst[dst_byte_offset] = (src_byte << 6);
2035                         current_bit_offset = 2;
2036                         break;
2037                 case 2:
2038                         dst[dst_byte_offset++] |= (src_byte);
2039                         dst[dst_byte_offset] = 0;
2040                         current_bit_offset = 0;
2041                         break;
2042                 }
2043                 src_byte_offset++;
2044         }
2045         (*dst_size) = dst_byte_offset;
2046 out:
2047         return;
2048 }
2049
2050 /**
2051  * ecryptfs_encrypt_and_encode_filename - converts a plaintext file name to cipher text
2052  * @crypt_stat: The crypt_stat struct associated with the file anem to encode
2053  * @name: The plaintext name
2054  * @length: The length of the plaintext
2055  * @encoded_name: The encypted name
2056  *
2057  * Encrypts and encodes a filename into something that constitutes a
2058  * valid filename for a filesystem, with printable characters.
2059  *
2060  * We assume that we have a properly initialized crypto context,
2061  * pointed to by crypt_stat->tfm.
2062  *
2063  * Returns zero on success; non-zero on otherwise
2064  */
2065 int ecryptfs_encrypt_and_encode_filename(
2066         char **encoded_name,
2067         size_t *encoded_name_size,
2068         struct ecryptfs_crypt_stat *crypt_stat,
2069         struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
2070         const char *name, size_t name_size)
2071 {
2072         size_t encoded_name_no_prefix_size;
2073         int rc = 0;
2074
2075         (*encoded_name) = NULL;
2076         (*encoded_name_size) = 0;
2077         if ((crypt_stat && (crypt_stat->flags & ECRYPTFS_ENCRYPT_FILENAMES))
2078             || (mount_crypt_stat && (mount_crypt_stat->flags
2079                                      & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES))) {
2080                 struct ecryptfs_filename *filename;
2081
2082                 filename = kzalloc(sizeof(*filename), GFP_KERNEL);
2083                 if (!filename) {
2084                         printk(KERN_ERR "%s: Out of memory whilst attempting "
2085                                "to kzalloc [%zd] bytes\n", __func__,
2086                                sizeof(*filename));
2087                         rc = -ENOMEM;
2088                         goto out;
2089                 }
2090                 filename->filename = (char *)name;
2091                 filename->filename_size = name_size;
2092                 rc = ecryptfs_encrypt_filename(filename, crypt_stat,
2093                                                mount_crypt_stat);
2094                 if (rc) {
2095                         printk(KERN_ERR "%s: Error attempting to encrypt "
2096                                "filename; rc = [%d]\n", __func__, rc);
2097                         kfree(filename);
2098                         goto out;
2099                 }
2100                 ecryptfs_encode_for_filename(
2101                         NULL, &encoded_name_no_prefix_size,
2102                         filename->encrypted_filename,
2103                         filename->encrypted_filename_size);
2104                 if ((crypt_stat && (crypt_stat->flags
2105                                     & ECRYPTFS_ENCFN_USE_MOUNT_FNEK))
2106                     || (mount_crypt_stat
2107                         && (mount_crypt_stat->flags
2108                             & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK)))
2109                         (*encoded_name_size) =
2110                                 (ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE
2111                                  + encoded_name_no_prefix_size);
2112                 else
2113                         (*encoded_name_size) =
2114                                 (ECRYPTFS_FEK_ENCRYPTED_FILENAME_PREFIX_SIZE
2115                                  + encoded_name_no_prefix_size);
2116                 (*encoded_name) = kmalloc((*encoded_name_size) + 1, GFP_KERNEL);
2117                 if (!(*encoded_name)) {
2118                         printk(KERN_ERR "%s: Out of memory whilst attempting "
2119                                "to kzalloc [%zd] bytes\n", __func__,
2120                                (*encoded_name_size));
2121                         rc = -ENOMEM;
2122                         kfree(filename->encrypted_filename);
2123                         kfree(filename);
2124                         goto out;
2125                 }
2126                 if ((crypt_stat && (crypt_stat->flags
2127                                     & ECRYPTFS_ENCFN_USE_MOUNT_FNEK))
2128                     || (mount_crypt_stat
2129                         && (mount_crypt_stat->flags
2130                             & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK))) {
2131                         memcpy((*encoded_name),
2132                                ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX,
2133                                ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE);
2134                         ecryptfs_encode_for_filename(
2135                             ((*encoded_name)
2136                              + ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE),
2137                             &encoded_name_no_prefix_size,
2138                             filename->encrypted_filename,
2139                             filename->encrypted_filename_size);
2140                         (*encoded_name_size) =
2141                                 (ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE
2142                                  + encoded_name_no_prefix_size);
2143                         (*encoded_name)[(*encoded_name_size)] = '\0';
2144                 } else {
2145                         rc = -EOPNOTSUPP;
2146                 }
2147                 if (rc) {
2148                         printk(KERN_ERR "%s: Error attempting to encode "
2149                                "encrypted filename; rc = [%d]\n", __func__,
2150                                rc);
2151                         kfree((*encoded_name));
2152                         (*encoded_name) = NULL;
2153                         (*encoded_name_size) = 0;
2154                 }
2155                 kfree(filename->encrypted_filename);
2156                 kfree(filename);
2157         } else {
2158                 rc = ecryptfs_copy_filename(encoded_name,
2159                                             encoded_name_size,
2160                                             name, name_size);
2161         }
2162 out:
2163         return rc;
2164 }
2165
2166 /**
2167  * ecryptfs_decode_and_decrypt_filename - converts the encoded cipher text name to decoded plaintext
2168  * @plaintext_name: The plaintext name
2169  * @plaintext_name_size: The plaintext name size
2170  * @ecryptfs_dir_dentry: eCryptfs directory dentry
2171  * @name: The filename in cipher text
2172  * @name_size: The cipher text name size
2173  *
2174  * Decrypts and decodes the filename.
2175  *
2176  * Returns zero on error; non-zero otherwise
2177  */
2178 int ecryptfs_decode_and_decrypt_filename(char **plaintext_name,
2179                                          size_t *plaintext_name_size,
2180                                          struct dentry *ecryptfs_dir_dentry,
2181                                          const char *name, size_t name_size)
2182 {
2183         struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
2184                 &ecryptfs_superblock_to_private(
2185                         ecryptfs_dir_dentry->d_sb)->mount_crypt_stat;
2186         char *decoded_name;
2187         size_t decoded_name_size;
2188         size_t packet_size;
2189         int rc = 0;
2190
2191         if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
2192             && !(mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
2193             && (name_size > ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE)
2194             && (strncmp(name, ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX,
2195                         ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE) == 0)) {
2196                 const char *orig_name = name;
2197                 size_t orig_name_size = name_size;
2198
2199                 name += ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE;
2200                 name_size -= ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE;
2201                 ecryptfs_decode_from_filename(NULL, &decoded_name_size,
2202                                               name, name_size);
2203                 decoded_name = kmalloc(decoded_name_size, GFP_KERNEL);
2204                 if (!decoded_name) {
2205                         printk(KERN_ERR "%s: Out of memory whilst attempting "
2206                                "to kmalloc [%zd] bytes\n", __func__,
2207                                decoded_name_size);
2208                         rc = -ENOMEM;
2209                         goto out;
2210                 }
2211                 ecryptfs_decode_from_filename(decoded_name, &decoded_name_size,
2212                                               name, name_size);
2213                 rc = ecryptfs_parse_tag_70_packet(plaintext_name,
2214                                                   plaintext_name_size,
2215                                                   &packet_size,
2216                                                   mount_crypt_stat,
2217                                                   decoded_name,
2218                                                   decoded_name_size);
2219                 if (rc) {
2220                         printk(KERN_INFO "%s: Could not parse tag 70 packet "
2221                                "from filename; copying through filename "
2222                                "as-is\n", __func__);
2223                         rc = ecryptfs_copy_filename(plaintext_name,
2224                                                     plaintext_name_size,
2225                                                     orig_name, orig_name_size);
2226                         goto out_free;
2227                 }
2228         } else {
2229                 rc = ecryptfs_copy_filename(plaintext_name,
2230                                             plaintext_name_size,
2231                                             name, name_size);
2232                 goto out;
2233         }
2234 out_free:
2235         kfree(decoded_name);
2236 out:
2237         return rc;
2238 }