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
  40static int
  41ecryptfs_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);
  45static int
  46ecryptfs_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 */
  58void 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 */
  73void 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 */
  95static 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	}
 141out:
 142	mutex_unlock(&crypt_stat->cs_hash_tfm_mutex);
 143	return rc;
 144}
 145
 146static 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;
 164out:
 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 */
 179int 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	}
 213out:
 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 */
 223void
 224ecryptfs_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 */
 241void 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
 257void 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 */
 291int 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 */
 335static 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);
 
 
 
 
 
 
 
 
 
 
 372out:
 
 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 */
 381static 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 */
 401static 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	if (unlikely(ecryptfs_verbosity > 0)) {
 421		ecryptfs_printk(KERN_DEBUG, "Encrypting extent "
 422				"with iv:\n");
 423		ecryptfs_dump_hex(extent_iv, crypt_stat->iv_bytes);
 424		ecryptfs_printk(KERN_DEBUG, "First 8 bytes before "
 425				"encryption:\n");
 426		ecryptfs_dump_hex((char *)
 427				  (page_address(page)
 428				   + (extent_offset * crypt_stat->extent_size)),
 429				  8);
 430	}
 431	rc = ecryptfs_encrypt_page_offset(crypt_stat, enc_extent_page, 0,
 432					  page, (extent_offset
 433						 * crypt_stat->extent_size),
 434					  crypt_stat->extent_size, extent_iv);
 435	if (rc < 0) {
 436		printk(KERN_ERR "%s: Error attempting to encrypt page with "
 437		       "page->index = [%ld], extent_offset = [%ld]; "
 438		       "rc = [%d]\n", __func__, page->index, extent_offset,
 439		       rc);
 440		goto out;
 441	}
 442	rc = 0;
 443	if (unlikely(ecryptfs_verbosity > 0)) {
 444		ecryptfs_printk(KERN_DEBUG, "Encrypt extent [0x%.16llx]; "
 445			"rc = [%d]\n",
 446			(unsigned long long)(extent_base + extent_offset), rc);
 447		ecryptfs_printk(KERN_DEBUG, "First 8 bytes after "
 448				"encryption:\n");
 449		ecryptfs_dump_hex((char *)(page_address(enc_extent_page)), 8);
 450	}
 451out:
 452	return rc;
 453}
 454
 455/**
 456 * ecryptfs_encrypt_page
 457 * @page: Page mapped from the eCryptfs inode for the file; contains
 458 *        decrypted content that needs to be encrypted (to a temporary
 459 *        page; not in place) and written out to the lower file
 460 *
 461 * Encrypt an eCryptfs page. This is done on a per-extent basis. Note
 462 * that eCryptfs pages may straddle the lower pages -- for instance,
 463 * if the file was created on a machine with an 8K page size
 464 * (resulting in an 8K header), and then the file is copied onto a
 465 * host with a 32K page size, then when reading page 0 of the eCryptfs
 466 * file, 24K of page 0 of the lower file will be read and decrypted,
 467 * and then 8K of page 1 of the lower file will be read and decrypted.
 468 *
 469 * Returns zero on success; negative on error
 470 */
 471int ecryptfs_encrypt_page(struct page *page)
 472{
 473	struct inode *ecryptfs_inode;
 474	struct ecryptfs_crypt_stat *crypt_stat;
 475	char *enc_extent_virt;
 476	struct page *enc_extent_page = NULL;
 477	loff_t extent_offset;
 
 478	int rc = 0;
 479
 480	ecryptfs_inode = page->mapping->host;
 481	crypt_stat =
 482		&(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat);
 483	BUG_ON(!(crypt_stat->flags & ECRYPTFS_ENCRYPTED));
 484	enc_extent_page = alloc_page(GFP_USER);
 485	if (!enc_extent_page) {
 486		rc = -ENOMEM;
 487		ecryptfs_printk(KERN_ERR, "Error allocating memory for "
 488				"encrypted extent\n");
 489		goto out;
 490	}
 491	enc_extent_virt = kmap(enc_extent_page);
 492	for (extent_offset = 0;
 493	     extent_offset < (PAGE_CACHE_SIZE / crypt_stat->extent_size);
 494	     extent_offset++) {
 495		loff_t offset;
 496
 497		rc = ecryptfs_encrypt_extent(enc_extent_page, crypt_stat, page,
 498					     extent_offset);
 499		if (rc) {
 500			printk(KERN_ERR "%s: Error encrypting extent; "
 501			       "rc = [%d]\n", __func__, rc);
 502			goto out;
 503		}
 504		ecryptfs_lower_offset_for_extent(
 505			&offset, ((((loff_t)page->index)
 506				   * (PAGE_CACHE_SIZE
 507				      / crypt_stat->extent_size))
 508				  + extent_offset), crypt_stat);
 509		rc = ecryptfs_write_lower(ecryptfs_inode, enc_extent_virt,
 510					  offset, crypt_stat->extent_size);
 511		if (rc < 0) {
 512			ecryptfs_printk(KERN_ERR, "Error attempting "
 513					"to write lower page; rc = [%d]"
 514					"\n", rc);
 515			goto out;
 516		}
 517	}
 518	rc = 0;
 519out:
 520	if (enc_extent_page) {
 521		kunmap(enc_extent_page);
 522		__free_page(enc_extent_page);
 523	}
 524	return rc;
 525}
 526
 527static int ecryptfs_decrypt_extent(struct page *page,
 528				   struct ecryptfs_crypt_stat *crypt_stat,
 529				   struct page *enc_extent_page,
 530				   unsigned long extent_offset)
 531{
 532	loff_t extent_base;
 533	char extent_iv[ECRYPTFS_MAX_IV_BYTES];
 534	int rc;
 535
 536	extent_base = (((loff_t)page->index)
 537		       * (PAGE_CACHE_SIZE / crypt_stat->extent_size));
 538	rc = ecryptfs_derive_iv(extent_iv, crypt_stat,
 539				(extent_base + extent_offset));
 540	if (rc) {
 541		ecryptfs_printk(KERN_ERR, "Error attempting to derive IV for "
 542			"extent [0x%.16llx]; rc = [%d]\n",
 543			(unsigned long long)(extent_base + extent_offset), rc);
 544		goto out;
 545	}
 546	if (unlikely(ecryptfs_verbosity > 0)) {
 547		ecryptfs_printk(KERN_DEBUG, "Decrypting extent "
 548				"with iv:\n");
 549		ecryptfs_dump_hex(extent_iv, crypt_stat->iv_bytes);
 550		ecryptfs_printk(KERN_DEBUG, "First 8 bytes before "
 551				"decryption:\n");
 552		ecryptfs_dump_hex((char *)
 553				  (page_address(enc_extent_page)
 554				   + (extent_offset * crypt_stat->extent_size)),
 555				  8);
 556	}
 557	rc = ecryptfs_decrypt_page_offset(crypt_stat, page,
 558					  (extent_offset
 559					   * crypt_stat->extent_size),
 560					  enc_extent_page, 0,
 561					  crypt_stat->extent_size, extent_iv);
 562	if (rc < 0) {
 563		printk(KERN_ERR "%s: Error attempting to decrypt to page with "
 564		       "page->index = [%ld], extent_offset = [%ld]; "
 565		       "rc = [%d]\n", __func__, page->index, extent_offset,
 566		       rc);
 567		goto out;
 568	}
 569	rc = 0;
 570	if (unlikely(ecryptfs_verbosity > 0)) {
 571		ecryptfs_printk(KERN_DEBUG, "Decrypt extent [0x%.16llx]; "
 572			"rc = [%d]\n",
 573			(unsigned long long)(extent_base + extent_offset), rc);
 574		ecryptfs_printk(KERN_DEBUG, "First 8 bytes after "
 575				"decryption:\n");
 576		ecryptfs_dump_hex((char *)(page_address(page)
 577					   + (extent_offset
 578					      * crypt_stat->extent_size)), 8);
 579	}
 580out:
 
 
 
 581	return rc;
 582}
 583
 584/**
 585 * ecryptfs_decrypt_page
 586 * @page: Page mapped from the eCryptfs inode for the file; data read
 587 *        and decrypted from the lower file will be written into this
 588 *        page
 589 *
 590 * Decrypt an eCryptfs page. This is done on a per-extent basis. Note
 591 * that eCryptfs pages may straddle the lower pages -- for instance,
 592 * if the file was created on a machine with an 8K page size
 593 * (resulting in an 8K header), and then the file is copied onto a
 594 * host with a 32K page size, then when reading page 0 of the eCryptfs
 595 * file, 24K of page 0 of the lower file will be read and decrypted,
 596 * and then 8K of page 1 of the lower file will be read and decrypted.
 597 *
 598 * Returns zero on success; negative on error
 599 */
 600int ecryptfs_decrypt_page(struct page *page)
 601{
 602	struct inode *ecryptfs_inode;
 603	struct ecryptfs_crypt_stat *crypt_stat;
 604	char *enc_extent_virt;
 605	struct page *enc_extent_page = NULL;
 606	unsigned long extent_offset;
 
 607	int rc = 0;
 608
 609	ecryptfs_inode = page->mapping->host;
 610	crypt_stat =
 611		&(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat);
 612	BUG_ON(!(crypt_stat->flags & ECRYPTFS_ENCRYPTED));
 613	enc_extent_page = alloc_page(GFP_USER);
 614	if (!enc_extent_page) {
 615		rc = -ENOMEM;
 616		ecryptfs_printk(KERN_ERR, "Error allocating memory for "
 617				"encrypted extent\n");
 
 
 
 
 
 618		goto out;
 619	}
 620	enc_extent_virt = kmap(enc_extent_page);
 621	for (extent_offset = 0;
 622	     extent_offset < (PAGE_CACHE_SIZE / crypt_stat->extent_size);
 623	     extent_offset++) {
 624		loff_t offset;
 625
 626		ecryptfs_lower_offset_for_extent(
 627			&offset, ((page->index * (PAGE_CACHE_SIZE
 628						  / crypt_stat->extent_size))
 629				  + extent_offset), crypt_stat);
 630		rc = ecryptfs_read_lower(enc_extent_virt, offset,
 631					 crypt_stat->extent_size,
 632					 ecryptfs_inode);
 633		if (rc < 0) {
 634			ecryptfs_printk(KERN_ERR, "Error attempting "
 635					"to read lower page; rc = [%d]"
 636					"\n", rc);
 637			goto out;
 638		}
 639		rc = ecryptfs_decrypt_extent(page, crypt_stat, enc_extent_page,
 640					     extent_offset);
 641		if (rc) {
 642			printk(KERN_ERR "%s: Error encrypting extent; "
 643			       "rc = [%d]\n", __func__, rc);
 644			goto out;
 645		}
 646	}
 647out:
 648	if (enc_extent_page) {
 649		kunmap(enc_extent_page);
 650		__free_page(enc_extent_page);
 651	}
 652	return rc;
 653}
 654
 655/**
 656 * decrypt_scatterlist
 657 * @crypt_stat: Cryptographic context
 658 * @dest_sg: The destination scatterlist to decrypt into
 659 * @src_sg: The source scatterlist to decrypt from
 660 * @size: The number of bytes to decrypt
 661 * @iv: The initialization vector to use for the decryption
 662 *
 663 * Returns the number of bytes decrypted; negative value on error
 664 */
 665static int decrypt_scatterlist(struct ecryptfs_crypt_stat *crypt_stat,
 666			       struct scatterlist *dest_sg,
 667			       struct scatterlist *src_sg, int size,
 668			       unsigned char *iv)
 669{
 670	struct blkcipher_desc desc = {
 671		.tfm = crypt_stat->tfm,
 672		.info = iv,
 673		.flags = CRYPTO_TFM_REQ_MAY_SLEEP
 674	};
 675	int rc = 0;
 676
 677	/* Consider doing this once, when the file is opened */
 678	mutex_lock(&crypt_stat->cs_tfm_mutex);
 679	rc = crypto_blkcipher_setkey(crypt_stat->tfm, crypt_stat->key,
 680				     crypt_stat->key_size);
 681	if (rc) {
 682		ecryptfs_printk(KERN_ERR, "Error setting key; rc = [%d]\n",
 683				rc);
 684		mutex_unlock(&crypt_stat->cs_tfm_mutex);
 685		rc = -EINVAL;
 686		goto out;
 687	}
 688	ecryptfs_printk(KERN_DEBUG, "Decrypting [%d] bytes.\n", size);
 689	rc = crypto_blkcipher_decrypt_iv(&desc, dest_sg, src_sg, size);
 690	mutex_unlock(&crypt_stat->cs_tfm_mutex);
 691	if (rc) {
 692		ecryptfs_printk(KERN_ERR, "Error decrypting; rc = [%d]\n",
 693				rc);
 694		goto out;
 695	}
 696	rc = size;
 697out:
 698	return rc;
 699}
 700
 701/**
 702 * ecryptfs_encrypt_page_offset
 703 * @crypt_stat: The cryptographic context
 704 * @dst_page: The page to encrypt into
 705 * @dst_offset: The offset in the page to encrypt into
 706 * @src_page: The page to encrypt from
 707 * @src_offset: The offset in the page to encrypt from
 708 * @size: The number of bytes to encrypt
 709 * @iv: The initialization vector to use for the encryption
 710 *
 711 * Returns the number of bytes encrypted
 712 */
 713static int
 714ecryptfs_encrypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat,
 715			     struct page *dst_page, int dst_offset,
 716			     struct page *src_page, int src_offset, int size,
 717			     unsigned char *iv)
 718{
 719	struct scatterlist src_sg, dst_sg;
 720
 721	sg_init_table(&src_sg, 1);
 722	sg_init_table(&dst_sg, 1);
 723
 724	sg_set_page(&src_sg, src_page, size, src_offset);
 725	sg_set_page(&dst_sg, dst_page, size, dst_offset);
 726	return encrypt_scatterlist(crypt_stat, &dst_sg, &src_sg, size, iv);
 727}
 728
 729/**
 730 * ecryptfs_decrypt_page_offset
 731 * @crypt_stat: The cryptographic context
 732 * @dst_page: The page to decrypt into
 733 * @dst_offset: The offset in the page to decrypt into
 734 * @src_page: The page to decrypt from
 735 * @src_offset: The offset in the page to decrypt from
 736 * @size: The number of bytes to decrypt
 737 * @iv: The initialization vector to use for the decryption
 738 *
 739 * Returns the number of bytes decrypted
 740 */
 741static int
 742ecryptfs_decrypt_page_offset(struct ecryptfs_crypt_stat *crypt_stat,
 743			     struct page *dst_page, int dst_offset,
 744			     struct page *src_page, int src_offset, int size,
 745			     unsigned char *iv)
 746{
 747	struct scatterlist src_sg, dst_sg;
 748
 749	sg_init_table(&src_sg, 1);
 750	sg_set_page(&src_sg, src_page, size, src_offset);
 751
 752	sg_init_table(&dst_sg, 1);
 753	sg_set_page(&dst_sg, dst_page, size, dst_offset);
 754
 755	return decrypt_scatterlist(crypt_stat, &dst_sg, &src_sg, size, iv);
 756}
 757
 758#define ECRYPTFS_MAX_SCATTERLIST_LEN 4
 759
 760/**
 761 * ecryptfs_init_crypt_ctx
 762 * @crypt_stat: Uninitialized crypt stats structure
 763 *
 764 * Initialize the crypto context.
 765 *
 766 * TODO: Performance: Keep a cache of initialized cipher contexts;
 767 * only init if needed
 768 */
 769int ecryptfs_init_crypt_ctx(struct ecryptfs_crypt_stat *crypt_stat)
 770{
 771	char *full_alg_name;
 772	int rc = -EINVAL;
 773
 774	if (!crypt_stat->cipher) {
 775		ecryptfs_printk(KERN_ERR, "No cipher specified\n");
 776		goto out;
 777	}
 778	ecryptfs_printk(KERN_DEBUG,
 779			"Initializing cipher [%s]; strlen = [%d]; "
 780			"key_size_bits = [%zd]\n",
 781			crypt_stat->cipher, (int)strlen(crypt_stat->cipher),
 782			crypt_stat->key_size << 3);
 
 783	if (crypt_stat->tfm) {
 784		rc = 0;
 785		goto out;
 786	}
 787	mutex_lock(&crypt_stat->cs_tfm_mutex);
 788	rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name,
 789						    crypt_stat->cipher, "cbc");
 790	if (rc)
 791		goto out_unlock;
 792	crypt_stat->tfm = crypto_alloc_blkcipher(full_alg_name, 0,
 793						 CRYPTO_ALG_ASYNC);
 794	kfree(full_alg_name);
 795	if (IS_ERR(crypt_stat->tfm)) {
 796		rc = PTR_ERR(crypt_stat->tfm);
 797		crypt_stat->tfm = NULL;
 798		ecryptfs_printk(KERN_ERR, "cryptfs: init_crypt_ctx(): "
 799				"Error initializing cipher [%s]\n",
 800				crypt_stat->cipher);
 801		goto out_unlock;
 802	}
 803	crypto_blkcipher_set_flags(crypt_stat->tfm, CRYPTO_TFM_REQ_WEAK_KEY);
 
 804	rc = 0;
 
 
 805out_unlock:
 806	mutex_unlock(&crypt_stat->cs_tfm_mutex);
 807out:
 808	return rc;
 809}
 810
 811static void set_extent_mask_and_shift(struct ecryptfs_crypt_stat *crypt_stat)
 812{
 813	int extent_size_tmp;
 814
 815	crypt_stat->extent_mask = 0xFFFFFFFF;
 816	crypt_stat->extent_shift = 0;
 817	if (crypt_stat->extent_size == 0)
 818		return;
 819	extent_size_tmp = crypt_stat->extent_size;
 820	while ((extent_size_tmp & 0x01) == 0) {
 821		extent_size_tmp >>= 1;
 822		crypt_stat->extent_mask <<= 1;
 823		crypt_stat->extent_shift++;
 824	}
 825}
 826
 827void ecryptfs_set_default_sizes(struct ecryptfs_crypt_stat *crypt_stat)
 828{
 829	/* Default values; may be overwritten as we are parsing the
 830	 * packets. */
 831	crypt_stat->extent_size = ECRYPTFS_DEFAULT_EXTENT_SIZE;
 832	set_extent_mask_and_shift(crypt_stat);
 833	crypt_stat->iv_bytes = ECRYPTFS_DEFAULT_IV_BYTES;
 834	if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
 835		crypt_stat->metadata_size = ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
 836	else {
 837		if (PAGE_CACHE_SIZE <= ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE)
 838			crypt_stat->metadata_size =
 839				ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
 840		else
 841			crypt_stat->metadata_size = PAGE_CACHE_SIZE;
 842	}
 843}
 844
 845/**
 846 * ecryptfs_compute_root_iv
 847 * @crypt_stats
 848 *
 849 * On error, sets the root IV to all 0's.
 850 */
 851int ecryptfs_compute_root_iv(struct ecryptfs_crypt_stat *crypt_stat)
 852{
 853	int rc = 0;
 854	char dst[MD5_DIGEST_SIZE];
 855
 856	BUG_ON(crypt_stat->iv_bytes > MD5_DIGEST_SIZE);
 857	BUG_ON(crypt_stat->iv_bytes <= 0);
 858	if (!(crypt_stat->flags & ECRYPTFS_KEY_VALID)) {
 859		rc = -EINVAL;
 860		ecryptfs_printk(KERN_WARNING, "Session key not valid; "
 861				"cannot generate root IV\n");
 862		goto out;
 863	}
 864	rc = ecryptfs_calculate_md5(dst, crypt_stat, crypt_stat->key,
 865				    crypt_stat->key_size);
 866	if (rc) {
 867		ecryptfs_printk(KERN_WARNING, "Error attempting to compute "
 868				"MD5 while generating root IV\n");
 869		goto out;
 870	}
 871	memcpy(crypt_stat->root_iv, dst, crypt_stat->iv_bytes);
 872out:
 873	if (rc) {
 874		memset(crypt_stat->root_iv, 0, crypt_stat->iv_bytes);
 875		crypt_stat->flags |= ECRYPTFS_SECURITY_WARNING;
 876	}
 877	return rc;
 878}
 879
 880static void ecryptfs_generate_new_key(struct ecryptfs_crypt_stat *crypt_stat)
 881{
 882	get_random_bytes(crypt_stat->key, crypt_stat->key_size);
 883	crypt_stat->flags |= ECRYPTFS_KEY_VALID;
 884	ecryptfs_compute_root_iv(crypt_stat);
 885	if (unlikely(ecryptfs_verbosity > 0)) {
 886		ecryptfs_printk(KERN_DEBUG, "Generated new session key:\n");
 887		ecryptfs_dump_hex(crypt_stat->key,
 888				  crypt_stat->key_size);
 889	}
 890}
 891
 892/**
 893 * ecryptfs_copy_mount_wide_flags_to_inode_flags
 894 * @crypt_stat: The inode's cryptographic context
 895 * @mount_crypt_stat: The mount point's cryptographic context
 896 *
 897 * This function propagates the mount-wide flags to individual inode
 898 * flags.
 899 */
 900static void ecryptfs_copy_mount_wide_flags_to_inode_flags(
 901	struct ecryptfs_crypt_stat *crypt_stat,
 902	struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
 903{
 904	if (mount_crypt_stat->flags & ECRYPTFS_XATTR_METADATA_ENABLED)
 905		crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
 906	if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
 907		crypt_stat->flags |= ECRYPTFS_VIEW_AS_ENCRYPTED;
 908	if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) {
 909		crypt_stat->flags |= ECRYPTFS_ENCRYPT_FILENAMES;
 910		if (mount_crypt_stat->flags
 911		    & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK)
 912			crypt_stat->flags |= ECRYPTFS_ENCFN_USE_MOUNT_FNEK;
 913		else if (mount_crypt_stat->flags
 914			 & ECRYPTFS_GLOBAL_ENCFN_USE_FEK)
 915			crypt_stat->flags |= ECRYPTFS_ENCFN_USE_FEK;
 916	}
 917}
 918
 919static int ecryptfs_copy_mount_wide_sigs_to_inode_sigs(
 920	struct ecryptfs_crypt_stat *crypt_stat,
 921	struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
 922{
 923	struct ecryptfs_global_auth_tok *global_auth_tok;
 924	int rc = 0;
 925
 926	mutex_lock(&crypt_stat->keysig_list_mutex);
 927	mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
 928
 929	list_for_each_entry(global_auth_tok,
 930			    &mount_crypt_stat->global_auth_tok_list,
 931			    mount_crypt_stat_list) {
 932		if (global_auth_tok->flags & ECRYPTFS_AUTH_TOK_FNEK)
 933			continue;
 934		rc = ecryptfs_add_keysig(crypt_stat, global_auth_tok->sig);
 935		if (rc) {
 936			printk(KERN_ERR "Error adding keysig; rc = [%d]\n", rc);
 937			goto out;
 938		}
 939	}
 940
 941out:
 942	mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
 943	mutex_unlock(&crypt_stat->keysig_list_mutex);
 944	return rc;
 945}
 946
 947/**
 948 * ecryptfs_set_default_crypt_stat_vals
 949 * @crypt_stat: The inode's cryptographic context
 950 * @mount_crypt_stat: The mount point's cryptographic context
 951 *
 952 * Default values in the event that policy does not override them.
 953 */
 954static void ecryptfs_set_default_crypt_stat_vals(
 955	struct ecryptfs_crypt_stat *crypt_stat,
 956	struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
 957{
 958	ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
 959						      mount_crypt_stat);
 960	ecryptfs_set_default_sizes(crypt_stat);
 961	strcpy(crypt_stat->cipher, ECRYPTFS_DEFAULT_CIPHER);
 962	crypt_stat->key_size = ECRYPTFS_DEFAULT_KEY_BYTES;
 963	crypt_stat->flags &= ~(ECRYPTFS_KEY_VALID);
 964	crypt_stat->file_version = ECRYPTFS_FILE_VERSION;
 965	crypt_stat->mount_crypt_stat = mount_crypt_stat;
 966}
 967
 968/**
 969 * ecryptfs_new_file_context
 970 * @ecryptfs_dentry: The eCryptfs dentry
 971 *
 972 * If the crypto context for the file has not yet been established,
 973 * this is where we do that.  Establishing a new crypto context
 974 * involves the following decisions:
 975 *  - What cipher to use?
 976 *  - What set of authentication tokens to use?
 977 * Here we just worry about getting enough information into the
 978 * authentication tokens so that we know that they are available.
 979 * We associate the available authentication tokens with the new file
 980 * via the set of signatures in the crypt_stat struct.  Later, when
 981 * the headers are actually written out, we may again defer to
 982 * userspace to perform the encryption of the session key; for the
 983 * foreseeable future, this will be the case with public key packets.
 984 *
 985 * Returns zero on success; non-zero otherwise
 986 */
 987int ecryptfs_new_file_context(struct dentry *ecryptfs_dentry)
 988{
 989	struct ecryptfs_crypt_stat *crypt_stat =
 990	    &ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat;
 991	struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
 992	    &ecryptfs_superblock_to_private(
 993		    ecryptfs_dentry->d_sb)->mount_crypt_stat;
 994	int cipher_name_len;
 995	int rc = 0;
 996
 997	ecryptfs_set_default_crypt_stat_vals(crypt_stat, mount_crypt_stat);
 998	crypt_stat->flags |= (ECRYPTFS_ENCRYPTED | ECRYPTFS_KEY_VALID);
 999	ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
1000						      mount_crypt_stat);
1001	rc = ecryptfs_copy_mount_wide_sigs_to_inode_sigs(crypt_stat,
1002							 mount_crypt_stat);
1003	if (rc) {
1004		printk(KERN_ERR "Error attempting to copy mount-wide key sigs "
1005		       "to the inode key sigs; rc = [%d]\n", rc);
1006		goto out;
1007	}
1008	cipher_name_len =
1009		strlen(mount_crypt_stat->global_default_cipher_name);
1010	memcpy(crypt_stat->cipher,
1011	       mount_crypt_stat->global_default_cipher_name,
1012	       cipher_name_len);
1013	crypt_stat->cipher[cipher_name_len] = '\0';
1014	crypt_stat->key_size =
1015		mount_crypt_stat->global_default_cipher_key_size;
1016	ecryptfs_generate_new_key(crypt_stat);
1017	rc = ecryptfs_init_crypt_ctx(crypt_stat);
1018	if (rc)
1019		ecryptfs_printk(KERN_ERR, "Error initializing cryptographic "
1020				"context for cipher [%s]: rc = [%d]\n",
1021				crypt_stat->cipher, rc);
1022out:
1023	return rc;
1024}
1025
1026/**
1027 * ecryptfs_validate_marker - check for the ecryptfs marker
1028 * @data: The data block in which to check
1029 *
1030 * Returns zero if marker found; -EINVAL if not found
1031 */
1032static int ecryptfs_validate_marker(char *data)
1033{
1034	u32 m_1, m_2;
1035
1036	m_1 = get_unaligned_be32(data);
1037	m_2 = get_unaligned_be32(data + 4);
1038	if ((m_1 ^ MAGIC_ECRYPTFS_MARKER) == m_2)
1039		return 0;
1040	ecryptfs_printk(KERN_DEBUG, "m_1 = [0x%.8x]; m_2 = [0x%.8x]; "
1041			"MAGIC_ECRYPTFS_MARKER = [0x%.8x]\n", m_1, m_2,
1042			MAGIC_ECRYPTFS_MARKER);
1043	ecryptfs_printk(KERN_DEBUG, "(m_1 ^ MAGIC_ECRYPTFS_MARKER) = "
1044			"[0x%.8x]\n", (m_1 ^ MAGIC_ECRYPTFS_MARKER));
1045	return -EINVAL;
1046}
1047
1048struct ecryptfs_flag_map_elem {
1049	u32 file_flag;
1050	u32 local_flag;
1051};
1052
1053/* Add support for additional flags by adding elements here. */
1054static struct ecryptfs_flag_map_elem ecryptfs_flag_map[] = {
1055	{0x00000001, ECRYPTFS_ENABLE_HMAC},
1056	{0x00000002, ECRYPTFS_ENCRYPTED},
1057	{0x00000004, ECRYPTFS_METADATA_IN_XATTR},
1058	{0x00000008, ECRYPTFS_ENCRYPT_FILENAMES}
1059};
1060
1061/**
1062 * ecryptfs_process_flags
1063 * @crypt_stat: The cryptographic context
1064 * @page_virt: Source data to be parsed
1065 * @bytes_read: Updated with the number of bytes read
1066 *
1067 * Returns zero on success; non-zero if the flag set is invalid
1068 */
1069static int ecryptfs_process_flags(struct ecryptfs_crypt_stat *crypt_stat,
1070				  char *page_virt, int *bytes_read)
1071{
1072	int rc = 0;
1073	int i;
1074	u32 flags;
1075
1076	flags = get_unaligned_be32(page_virt);
1077	for (i = 0; i < ((sizeof(ecryptfs_flag_map)
1078			  / sizeof(struct ecryptfs_flag_map_elem))); i++)
1079		if (flags & ecryptfs_flag_map[i].file_flag) {
1080			crypt_stat->flags |= ecryptfs_flag_map[i].local_flag;
1081		} else
1082			crypt_stat->flags &= ~(ecryptfs_flag_map[i].local_flag);
1083	/* Version is in top 8 bits of the 32-bit flag vector */
1084	crypt_stat->file_version = ((flags >> 24) & 0xFF);
1085	(*bytes_read) = 4;
1086	return rc;
1087}
1088
1089/**
1090 * write_ecryptfs_marker
1091 * @page_virt: The pointer to in a page to begin writing the marker
1092 * @written: Number of bytes written
1093 *
1094 * Marker = 0x3c81b7f5
1095 */
1096static void write_ecryptfs_marker(char *page_virt, size_t *written)
1097{
1098	u32 m_1, m_2;
1099
1100	get_random_bytes(&m_1, (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2));
1101	m_2 = (m_1 ^ MAGIC_ECRYPTFS_MARKER);
1102	put_unaligned_be32(m_1, page_virt);
1103	page_virt += (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2);
1104	put_unaligned_be32(m_2, page_virt);
1105	(*written) = MAGIC_ECRYPTFS_MARKER_SIZE_BYTES;
1106}
1107
1108void ecryptfs_write_crypt_stat_flags(char *page_virt,
1109				     struct ecryptfs_crypt_stat *crypt_stat,
1110				     size_t *written)
1111{
1112	u32 flags = 0;
1113	int i;
1114
1115	for (i = 0; i < ((sizeof(ecryptfs_flag_map)
1116			  / sizeof(struct ecryptfs_flag_map_elem))); i++)
1117		if (crypt_stat->flags & ecryptfs_flag_map[i].local_flag)
1118			flags |= ecryptfs_flag_map[i].file_flag;
1119	/* Version is in top 8 bits of the 32-bit flag vector */
1120	flags |= ((((u8)crypt_stat->file_version) << 24) & 0xFF000000);
1121	put_unaligned_be32(flags, page_virt);
1122	(*written) = 4;
1123}
1124
1125struct ecryptfs_cipher_code_str_map_elem {
1126	char cipher_str[16];
1127	u8 cipher_code;
1128};
1129
1130/* Add support for additional ciphers by adding elements here. The
1131 * cipher_code is whatever OpenPGP applicatoins use to identify the
1132 * ciphers. List in order of probability. */
1133static struct ecryptfs_cipher_code_str_map_elem
1134ecryptfs_cipher_code_str_map[] = {
1135	{"aes",RFC2440_CIPHER_AES_128 },
1136	{"blowfish", RFC2440_CIPHER_BLOWFISH},
1137	{"des3_ede", RFC2440_CIPHER_DES3_EDE},
1138	{"cast5", RFC2440_CIPHER_CAST_5},
1139	{"twofish", RFC2440_CIPHER_TWOFISH},
1140	{"cast6", RFC2440_CIPHER_CAST_6},
1141	{"aes", RFC2440_CIPHER_AES_192},
1142	{"aes", RFC2440_CIPHER_AES_256}
1143};
1144
1145/**
1146 * ecryptfs_code_for_cipher_string
1147 * @cipher_name: The string alias for the cipher
1148 * @key_bytes: Length of key in bytes; used for AES code selection
1149 *
1150 * Returns zero on no match, or the cipher code on match
1151 */
1152u8 ecryptfs_code_for_cipher_string(char *cipher_name, size_t key_bytes)
1153{
1154	int i;
1155	u8 code = 0;
1156	struct ecryptfs_cipher_code_str_map_elem *map =
1157		ecryptfs_cipher_code_str_map;
1158
1159	if (strcmp(cipher_name, "aes") == 0) {
1160		switch (key_bytes) {
1161		case 16:
1162			code = RFC2440_CIPHER_AES_128;
1163			break;
1164		case 24:
1165			code = RFC2440_CIPHER_AES_192;
1166			break;
1167		case 32:
1168			code = RFC2440_CIPHER_AES_256;
1169		}
1170	} else {
1171		for (i = 0; i < ARRAY_SIZE(ecryptfs_cipher_code_str_map); i++)
1172			if (strcmp(cipher_name, map[i].cipher_str) == 0) {
1173				code = map[i].cipher_code;
1174				break;
1175			}
1176	}
1177	return code;
1178}
1179
1180/**
1181 * ecryptfs_cipher_code_to_string
1182 * @str: Destination to write out the cipher name
1183 * @cipher_code: The code to convert to cipher name string
1184 *
1185 * Returns zero on success
1186 */
1187int ecryptfs_cipher_code_to_string(char *str, u8 cipher_code)
1188{
1189	int rc = 0;
1190	int i;
1191
1192	str[0] = '\0';
1193	for (i = 0; i < ARRAY_SIZE(ecryptfs_cipher_code_str_map); i++)
1194		if (cipher_code == ecryptfs_cipher_code_str_map[i].cipher_code)
1195			strcpy(str, ecryptfs_cipher_code_str_map[i].cipher_str);
1196	if (str[0] == '\0') {
1197		ecryptfs_printk(KERN_WARNING, "Cipher code not recognized: "
1198				"[%d]\n", cipher_code);
1199		rc = -EINVAL;
1200	}
1201	return rc;
1202}
1203
1204int ecryptfs_read_and_validate_header_region(struct inode *inode)
1205{
1206	u8 file_size[ECRYPTFS_SIZE_AND_MARKER_BYTES];
1207	u8 *marker = file_size + ECRYPTFS_FILE_SIZE_BYTES;
1208	int rc;
1209
1210	rc = ecryptfs_read_lower(file_size, 0, ECRYPTFS_SIZE_AND_MARKER_BYTES,
1211				 inode);
1212	if (rc < ECRYPTFS_SIZE_AND_MARKER_BYTES)
1213		return rc >= 0 ? -EINVAL : rc;
 
 
1214	rc = ecryptfs_validate_marker(marker);
1215	if (!rc)
1216		ecryptfs_i_size_init(file_size, inode);
1217	return rc;
1218}
1219
1220void
1221ecryptfs_write_header_metadata(char *virt,
1222			       struct ecryptfs_crypt_stat *crypt_stat,
1223			       size_t *written)
1224{
1225	u32 header_extent_size;
1226	u16 num_header_extents_at_front;
1227
1228	header_extent_size = (u32)crypt_stat->extent_size;
1229	num_header_extents_at_front =
1230		(u16)(crypt_stat->metadata_size / crypt_stat->extent_size);
1231	put_unaligned_be32(header_extent_size, virt);
1232	virt += 4;
1233	put_unaligned_be16(num_header_extents_at_front, virt);
1234	(*written) = 6;
1235}
1236
1237struct kmem_cache *ecryptfs_header_cache;
1238
1239/**
1240 * ecryptfs_write_headers_virt
1241 * @page_virt: The virtual address to write the headers to
1242 * @max: The size of memory allocated at page_virt
1243 * @size: Set to the number of bytes written by this function
1244 * @crypt_stat: The cryptographic context
1245 * @ecryptfs_dentry: The eCryptfs dentry
1246 *
1247 * Format version: 1
1248 *
1249 *   Header Extent:
1250 *     Octets 0-7:        Unencrypted file size (big-endian)
1251 *     Octets 8-15:       eCryptfs special marker
1252 *     Octets 16-19:      Flags
1253 *      Octet 16:         File format version number (between 0 and 255)
1254 *      Octets 17-18:     Reserved
1255 *      Octet 19:         Bit 1 (lsb): Reserved
1256 *                        Bit 2: Encrypted?
1257 *                        Bits 3-8: Reserved
1258 *     Octets 20-23:      Header extent size (big-endian)
1259 *     Octets 24-25:      Number of header extents at front of file
1260 *                        (big-endian)
1261 *     Octet  26:         Begin RFC 2440 authentication token packet set
1262 *   Data Extent 0:
1263 *     Lower data (CBC encrypted)
1264 *   Data Extent 1:
1265 *     Lower data (CBC encrypted)
1266 *   ...
1267 *
1268 * Returns zero on success
1269 */
1270static int ecryptfs_write_headers_virt(char *page_virt, size_t max,
1271				       size_t *size,
1272				       struct ecryptfs_crypt_stat *crypt_stat,
1273				       struct dentry *ecryptfs_dentry)
1274{
1275	int rc;
1276	size_t written;
1277	size_t offset;
1278
1279	offset = ECRYPTFS_FILE_SIZE_BYTES;
1280	write_ecryptfs_marker((page_virt + offset), &written);
1281	offset += written;
1282	ecryptfs_write_crypt_stat_flags((page_virt + offset), crypt_stat,
1283					&written);
1284	offset += written;
1285	ecryptfs_write_header_metadata((page_virt + offset), crypt_stat,
1286				       &written);
1287	offset += written;
1288	rc = ecryptfs_generate_key_packet_set((page_virt + offset), crypt_stat,
1289					      ecryptfs_dentry, &written,
1290					      max - offset);
1291	if (rc)
1292		ecryptfs_printk(KERN_WARNING, "Error generating key packet "
1293				"set; rc = [%d]\n", rc);
1294	if (size) {
1295		offset += written;
1296		*size = offset;
1297	}
1298	return rc;
1299}
1300
1301static int
1302ecryptfs_write_metadata_to_contents(struct dentry *ecryptfs_dentry,
1303				    char *virt, size_t virt_len)
1304{
1305	int rc;
1306
1307	rc = ecryptfs_write_lower(ecryptfs_dentry->d_inode, virt,
1308				  0, virt_len);
1309	if (rc < 0)
1310		printk(KERN_ERR "%s: Error attempting to write header "
1311		       "information to lower file; rc = [%d]\n", __func__, rc);
1312	else
1313		rc = 0;
1314	return rc;
1315}
1316
1317static int
1318ecryptfs_write_metadata_to_xattr(struct dentry *ecryptfs_dentry,
 
1319				 char *page_virt, size_t size)
1320{
1321	int rc;
 
 
 
 
 
 
 
1322
1323	rc = ecryptfs_setxattr(ecryptfs_dentry, ECRYPTFS_XATTR_NAME, page_virt,
1324			       size, 0);
 
 
 
 
 
1325	return rc;
1326}
1327
1328static unsigned long ecryptfs_get_zeroed_pages(gfp_t gfp_mask,
1329					       unsigned int order)
1330{
1331	struct page *page;
1332
1333	page = alloc_pages(gfp_mask | __GFP_ZERO, order);
1334	if (page)
1335		return (unsigned long) page_address(page);
1336	return 0;
1337}
1338
1339/**
1340 * ecryptfs_write_metadata
1341 * @ecryptfs_dentry: The eCryptfs dentry
 
1342 *
1343 * Write the file headers out.  This will likely involve a userspace
1344 * callout, in which the session key is encrypted with one or more
1345 * public keys and/or the passphrase necessary to do the encryption is
1346 * retrieved via a prompt.  Exactly what happens at this point should
1347 * be policy-dependent.
1348 *
1349 * Returns zero on success; non-zero on error
1350 */
1351int ecryptfs_write_metadata(struct dentry *ecryptfs_dentry)
 
1352{
1353	struct ecryptfs_crypt_stat *crypt_stat =
1354		&ecryptfs_inode_to_private(ecryptfs_dentry->d_inode)->crypt_stat;
1355	unsigned int order;
1356	char *virt;
1357	size_t virt_len;
1358	size_t size = 0;
1359	int rc = 0;
1360
1361	if (likely(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
1362		if (!(crypt_stat->flags & ECRYPTFS_KEY_VALID)) {
1363			printk(KERN_ERR "Key is invalid; bailing out\n");
1364			rc = -EINVAL;
1365			goto out;
1366		}
1367	} else {
1368		printk(KERN_WARNING "%s: Encrypted flag not set\n",
1369		       __func__);
1370		rc = -EINVAL;
1371		goto out;
1372	}
1373	virt_len = crypt_stat->metadata_size;
1374	order = get_order(virt_len);
1375	/* Released in this function */
1376	virt = (char *)ecryptfs_get_zeroed_pages(GFP_KERNEL, order);
1377	if (!virt) {
1378		printk(KERN_ERR "%s: Out of memory\n", __func__);
1379		rc = -ENOMEM;
1380		goto out;
1381	}
1382	/* Zeroed page ensures the in-header unencrypted i_size is set to 0 */
1383	rc = ecryptfs_write_headers_virt(virt, virt_len, &size, crypt_stat,
1384					 ecryptfs_dentry);
1385	if (unlikely(rc)) {
1386		printk(KERN_ERR "%s: Error whilst writing headers; rc = [%d]\n",
1387		       __func__, rc);
1388		goto out_free;
1389	}
1390	if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
1391		rc = ecryptfs_write_metadata_to_xattr(ecryptfs_dentry, virt,
1392						      size);
1393	else
1394		rc = ecryptfs_write_metadata_to_contents(ecryptfs_dentry, virt,
1395							 virt_len);
1396	if (rc) {
1397		printk(KERN_ERR "%s: Error writing metadata out to lower file; "
1398		       "rc = [%d]\n", __func__, rc);
1399		goto out_free;
1400	}
1401out_free:
1402	free_pages((unsigned long)virt, order);
1403out:
1404	return rc;
1405}
1406
1407#define ECRYPTFS_DONT_VALIDATE_HEADER_SIZE 0
1408#define ECRYPTFS_VALIDATE_HEADER_SIZE 1
1409static int parse_header_metadata(struct ecryptfs_crypt_stat *crypt_stat,
1410				 char *virt, int *bytes_read,
1411				 int validate_header_size)
1412{
1413	int rc = 0;
1414	u32 header_extent_size;
1415	u16 num_header_extents_at_front;
1416
1417	header_extent_size = get_unaligned_be32(virt);
1418	virt += sizeof(__be32);
1419	num_header_extents_at_front = get_unaligned_be16(virt);
1420	crypt_stat->metadata_size = (((size_t)num_header_extents_at_front
1421				     * (size_t)header_extent_size));
1422	(*bytes_read) = (sizeof(__be32) + sizeof(__be16));
1423	if ((validate_header_size == ECRYPTFS_VALIDATE_HEADER_SIZE)
1424	    && (crypt_stat->metadata_size
1425		< ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE)) {
1426		rc = -EINVAL;
1427		printk(KERN_WARNING "Invalid header size: [%zd]\n",
1428		       crypt_stat->metadata_size);
1429	}
1430	return rc;
1431}
1432
1433/**
1434 * set_default_header_data
1435 * @crypt_stat: The cryptographic context
1436 *
1437 * For version 0 file format; this function is only for backwards
1438 * compatibility for files created with the prior versions of
1439 * eCryptfs.
1440 */
1441static void set_default_header_data(struct ecryptfs_crypt_stat *crypt_stat)
1442{
1443	crypt_stat->metadata_size = ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
1444}
1445
1446void ecryptfs_i_size_init(const char *page_virt, struct inode *inode)
1447{
1448	struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
1449	struct ecryptfs_crypt_stat *crypt_stat;
1450	u64 file_size;
1451
1452	crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
1453	mount_crypt_stat =
1454		&ecryptfs_superblock_to_private(inode->i_sb)->mount_crypt_stat;
1455	if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED) {
1456		file_size = i_size_read(ecryptfs_inode_to_lower(inode));
1457		if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
1458			file_size += crypt_stat->metadata_size;
1459	} else
1460		file_size = get_unaligned_be64(page_virt);
1461	i_size_write(inode, (loff_t)file_size);
1462	crypt_stat->flags |= ECRYPTFS_I_SIZE_INITIALIZED;
1463}
1464
1465/**
1466 * ecryptfs_read_headers_virt
1467 * @page_virt: The virtual address into which to read the headers
1468 * @crypt_stat: The cryptographic context
1469 * @ecryptfs_dentry: The eCryptfs dentry
1470 * @validate_header_size: Whether to validate the header size while reading
1471 *
1472 * Read/parse the header data. The header format is detailed in the
1473 * comment block for the ecryptfs_write_headers_virt() function.
1474 *
1475 * Returns zero on success
1476 */
1477static int ecryptfs_read_headers_virt(char *page_virt,
1478				      struct ecryptfs_crypt_stat *crypt_stat,
1479				      struct dentry *ecryptfs_dentry,
1480				      int validate_header_size)
1481{
1482	int rc = 0;
1483	int offset;
1484	int bytes_read;
1485
1486	ecryptfs_set_default_sizes(crypt_stat);
1487	crypt_stat->mount_crypt_stat = &ecryptfs_superblock_to_private(
1488		ecryptfs_dentry->d_sb)->mount_crypt_stat;
1489	offset = ECRYPTFS_FILE_SIZE_BYTES;
1490	rc = ecryptfs_validate_marker(page_virt + offset);
1491	if (rc)
1492		goto out;
1493	if (!(crypt_stat->flags & ECRYPTFS_I_SIZE_INITIALIZED))
1494		ecryptfs_i_size_init(page_virt, ecryptfs_dentry->d_inode);
1495	offset += MAGIC_ECRYPTFS_MARKER_SIZE_BYTES;
1496	rc = ecryptfs_process_flags(crypt_stat, (page_virt + offset),
1497				    &bytes_read);
1498	if (rc) {
1499		ecryptfs_printk(KERN_WARNING, "Error processing flags\n");
1500		goto out;
1501	}
1502	if (crypt_stat->file_version > ECRYPTFS_SUPPORTED_FILE_VERSION) {
1503		ecryptfs_printk(KERN_WARNING, "File version is [%d]; only "
1504				"file version [%d] is supported by this "
1505				"version of eCryptfs\n",
1506				crypt_stat->file_version,
1507				ECRYPTFS_SUPPORTED_FILE_VERSION);
1508		rc = -EINVAL;
1509		goto out;
1510	}
1511	offset += bytes_read;
1512	if (crypt_stat->file_version >= 1) {
1513		rc = parse_header_metadata(crypt_stat, (page_virt + offset),
1514					   &bytes_read, validate_header_size);
1515		if (rc) {
1516			ecryptfs_printk(KERN_WARNING, "Error reading header "
1517					"metadata; rc = [%d]\n", rc);
1518		}
1519		offset += bytes_read;
1520	} else
1521		set_default_header_data(crypt_stat);
1522	rc = ecryptfs_parse_packet_set(crypt_stat, (page_virt + offset),
1523				       ecryptfs_dentry);
1524out:
1525	return rc;
1526}
1527
1528/**
1529 * ecryptfs_read_xattr_region
1530 * @page_virt: The vitual address into which to read the xattr data
1531 * @ecryptfs_inode: The eCryptfs inode
1532 *
1533 * Attempts to read the crypto metadata from the extended attribute
1534 * region of the lower file.
1535 *
1536 * Returns zero on success; non-zero on error
1537 */
1538int ecryptfs_read_xattr_region(char *page_virt, struct inode *ecryptfs_inode)
1539{
1540	struct dentry *lower_dentry =
1541		ecryptfs_inode_to_private(ecryptfs_inode)->lower_file->f_dentry;
1542	ssize_t size;
1543	int rc = 0;
1544
1545	size = ecryptfs_getxattr_lower(lower_dentry, ECRYPTFS_XATTR_NAME,
 
 
1546				       page_virt, ECRYPTFS_DEFAULT_EXTENT_SIZE);
1547	if (size < 0) {
1548		if (unlikely(ecryptfs_verbosity > 0))
1549			printk(KERN_INFO "Error attempting to read the [%s] "
1550			       "xattr from the lower file; return value = "
1551			       "[%zd]\n", ECRYPTFS_XATTR_NAME, size);
1552		rc = -EINVAL;
1553		goto out;
1554	}
1555out:
1556	return rc;
1557}
1558
1559int ecryptfs_read_and_validate_xattr_region(struct dentry *dentry,
1560					    struct inode *inode)
1561{
1562	u8 file_size[ECRYPTFS_SIZE_AND_MARKER_BYTES];
1563	u8 *marker = file_size + ECRYPTFS_FILE_SIZE_BYTES;
1564	int rc;
1565
1566	rc = ecryptfs_getxattr_lower(ecryptfs_dentry_to_lower(dentry),
 
1567				     ECRYPTFS_XATTR_NAME, file_size,
1568				     ECRYPTFS_SIZE_AND_MARKER_BYTES);
1569	if (rc < ECRYPTFS_SIZE_AND_MARKER_BYTES)
1570		return rc >= 0 ? -EINVAL : rc;
 
 
1571	rc = ecryptfs_validate_marker(marker);
1572	if (!rc)
1573		ecryptfs_i_size_init(file_size, inode);
1574	return rc;
1575}
1576
1577/**
1578 * ecryptfs_read_metadata
1579 *
1580 * Common entry point for reading file metadata. From here, we could
1581 * retrieve the header information from the header region of the file,
1582 * the xattr region of the file, or some other repostory that is
1583 * stored separately from the file itself. The current implementation
1584 * supports retrieving the metadata information from the file contents
1585 * and from the xattr region.
1586 *
1587 * Returns zero if valid headers found and parsed; non-zero otherwise
1588 */
1589int ecryptfs_read_metadata(struct dentry *ecryptfs_dentry)
1590{
1591	int rc = 0;
1592	char *page_virt = NULL;
1593	struct inode *ecryptfs_inode = ecryptfs_dentry->d_inode;
1594	struct ecryptfs_crypt_stat *crypt_stat =
1595	    &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
1596	struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
1597		&ecryptfs_superblock_to_private(
1598			ecryptfs_dentry->d_sb)->mount_crypt_stat;
1599
1600	ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
1601						      mount_crypt_stat);
1602	/* Read the first page from the underlying file */
1603	page_virt = kmem_cache_alloc(ecryptfs_header_cache, GFP_USER);
1604	if (!page_virt) {
1605		rc = -ENOMEM;
1606		printk(KERN_ERR "%s: Unable to allocate page_virt\n",
1607		       __func__);
1608		goto out;
1609	}
1610	rc = ecryptfs_read_lower(page_virt, 0, crypt_stat->extent_size,
1611				 ecryptfs_inode);
1612	if (rc >= 0)
1613		rc = ecryptfs_read_headers_virt(page_virt, crypt_stat,
1614						ecryptfs_dentry,
1615						ECRYPTFS_VALIDATE_HEADER_SIZE);
1616	if (rc) {
1617		memset(page_virt, 0, PAGE_CACHE_SIZE);
 
1618		rc = ecryptfs_read_xattr_region(page_virt, ecryptfs_inode);
1619		if (rc) {
1620			printk(KERN_DEBUG "Valid eCryptfs headers not found in "
1621			       "file header region or xattr region\n");
 
1622			rc = -EINVAL;
1623			goto out;
1624		}
1625		rc = ecryptfs_read_headers_virt(page_virt, crypt_stat,
1626						ecryptfs_dentry,
1627						ECRYPTFS_DONT_VALIDATE_HEADER_SIZE);
1628		if (rc) {
1629			printk(KERN_DEBUG "Valid eCryptfs headers not found in "
1630			       "file xattr region either\n");
 
1631			rc = -EINVAL;
1632		}
1633		if (crypt_stat->mount_crypt_stat->flags
1634		    & ECRYPTFS_XATTR_METADATA_ENABLED) {
1635			crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
1636		} else {
1637			printk(KERN_WARNING "Attempt to access file with "
1638			       "crypto metadata only in the extended attribute "
1639			       "region, but eCryptfs was mounted without "
1640			       "xattr support enabled. eCryptfs will not treat "
1641			       "this like an encrypted file.\n");
 
1642			rc = -EINVAL;
1643		}
1644	}
1645out:
1646	if (page_virt) {
1647		memset(page_virt, 0, PAGE_CACHE_SIZE);
1648		kmem_cache_free(ecryptfs_header_cache, page_virt);
1649	}
1650	return rc;
1651}
1652
1653/**
1654 * ecryptfs_encrypt_filename - encrypt filename
1655 *
1656 * CBC-encrypts the filename. We do not want to encrypt the same
1657 * filename with the same key and IV, which may happen with hard
1658 * links, so we prepend random bits to each filename.
1659 *
1660 * Returns zero on success; non-zero otherwise
1661 */
1662static int
1663ecryptfs_encrypt_filename(struct ecryptfs_filename *filename,
1664			  struct ecryptfs_crypt_stat *crypt_stat,
1665			  struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
1666{
1667	int rc = 0;
1668
1669	filename->encrypted_filename = NULL;
1670	filename->encrypted_filename_size = 0;
1671	if ((crypt_stat && (crypt_stat->flags & ECRYPTFS_ENCFN_USE_MOUNT_FNEK))
1672	    || (mount_crypt_stat && (mount_crypt_stat->flags
1673				     & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK))) {
1674		size_t packet_size;
1675		size_t remaining_bytes;
1676
1677		rc = ecryptfs_write_tag_70_packet(
1678			NULL, NULL,
1679			&filename->encrypted_filename_size,
1680			mount_crypt_stat, NULL,
1681			filename->filename_size);
1682		if (rc) {
1683			printk(KERN_ERR "%s: Error attempting to get packet "
1684			       "size for tag 72; rc = [%d]\n", __func__,
1685			       rc);
1686			filename->encrypted_filename_size = 0;
1687			goto out;
1688		}
1689		filename->encrypted_filename =
1690			kmalloc(filename->encrypted_filename_size, GFP_KERNEL);
1691		if (!filename->encrypted_filename) {
1692			printk(KERN_ERR "%s: Out of memory whilst attempting "
1693			       "to kmalloc [%zd] bytes\n", __func__,
1694			       filename->encrypted_filename_size);
1695			rc = -ENOMEM;
1696			goto out;
1697		}
1698		remaining_bytes = filename->encrypted_filename_size;
1699		rc = ecryptfs_write_tag_70_packet(filename->encrypted_filename,
1700						  &remaining_bytes,
1701						  &packet_size,
1702						  mount_crypt_stat,
1703						  filename->filename,
1704						  filename->filename_size);
1705		if (rc) {
1706			printk(KERN_ERR "%s: Error attempting to generate "
1707			       "tag 70 packet; rc = [%d]\n", __func__,
1708			       rc);
1709			kfree(filename->encrypted_filename);
1710			filename->encrypted_filename = NULL;
1711			filename->encrypted_filename_size = 0;
1712			goto out;
1713		}
1714		filename->encrypted_filename_size = packet_size;
1715	} else {
1716		printk(KERN_ERR "%s: No support for requested filename "
1717		       "encryption method in this release\n", __func__);
1718		rc = -EOPNOTSUPP;
1719		goto out;
1720	}
1721out:
1722	return rc;
1723}
1724
1725static int ecryptfs_copy_filename(char **copied_name, size_t *copied_name_size,
1726				  const char *name, size_t name_size)
1727{
1728	int rc = 0;
1729
1730	(*copied_name) = kmalloc((name_size + 1), GFP_KERNEL);
1731	if (!(*copied_name)) {
1732		rc = -ENOMEM;
1733		goto out;
1734	}
1735	memcpy((void *)(*copied_name), (void *)name, name_size);
1736	(*copied_name)[(name_size)] = '\0';	/* Only for convenience
1737						 * in printing out the
1738						 * string in debug
1739						 * messages */
1740	(*copied_name_size) = name_size;
1741out:
1742	return rc;
1743}
1744
1745/**
1746 * ecryptfs_process_key_cipher - Perform key cipher initialization.
1747 * @key_tfm: Crypto context for key material, set by this function
1748 * @cipher_name: Name of the cipher
1749 * @key_size: Size of the key in bytes
1750 *
1751 * Returns zero on success. Any crypto_tfm structs allocated here
1752 * should be released by other functions, such as on a superblock put
1753 * event, regardless of whether this function succeeds for fails.
1754 */
1755static int
1756ecryptfs_process_key_cipher(struct crypto_blkcipher **key_tfm,
1757			    char *cipher_name, size_t *key_size)
1758{
1759	char dummy_key[ECRYPTFS_MAX_KEY_BYTES];
1760	char *full_alg_name = NULL;
1761	int rc;
1762
1763	*key_tfm = NULL;
1764	if (*key_size > ECRYPTFS_MAX_KEY_BYTES) {
1765		rc = -EINVAL;
1766		printk(KERN_ERR "Requested key size is [%zd] bytes; maximum "
1767		      "allowable is [%d]\n", *key_size, ECRYPTFS_MAX_KEY_BYTES);
1768		goto out;
1769	}
1770	rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name, cipher_name,
1771						    "ecb");
1772	if (rc)
1773		goto out;
1774	*key_tfm = crypto_alloc_blkcipher(full_alg_name, 0, CRYPTO_ALG_ASYNC);
1775	if (IS_ERR(*key_tfm)) {
1776		rc = PTR_ERR(*key_tfm);
1777		printk(KERN_ERR "Unable to allocate crypto cipher with name "
1778		       "[%s]; rc = [%d]\n", full_alg_name, rc);
1779		goto out;
1780	}
1781	crypto_blkcipher_set_flags(*key_tfm, CRYPTO_TFM_REQ_WEAK_KEY);
1782	if (*key_size == 0) {
1783		struct blkcipher_alg *alg = crypto_blkcipher_alg(*key_tfm);
1784
1785		*key_size = alg->max_keysize;
1786	}
1787	get_random_bytes(dummy_key, *key_size);
1788	rc = crypto_blkcipher_setkey(*key_tfm, dummy_key, *key_size);
1789	if (rc) {
1790		printk(KERN_ERR "Error attempting to set key of size [%zd] for "
1791		       "cipher [%s]; rc = [%d]\n", *key_size, full_alg_name,
1792		       rc);
1793		rc = -EINVAL;
1794		goto out;
1795	}
1796out:
1797	kfree(full_alg_name);
1798	return rc;
1799}
1800
1801struct kmem_cache *ecryptfs_key_tfm_cache;
1802static struct list_head key_tfm_list;
1803struct mutex key_tfm_list_mutex;
1804
1805int __init ecryptfs_init_crypto(void)
1806{
1807	mutex_init(&key_tfm_list_mutex);
1808	INIT_LIST_HEAD(&key_tfm_list);
1809	return 0;
1810}
1811
1812/**
1813 * ecryptfs_destroy_crypto - free all cached key_tfms on key_tfm_list
1814 *
1815 * Called only at module unload time
1816 */
1817int ecryptfs_destroy_crypto(void)
1818{
1819	struct ecryptfs_key_tfm *key_tfm, *key_tfm_tmp;
1820
1821	mutex_lock(&key_tfm_list_mutex);
1822	list_for_each_entry_safe(key_tfm, key_tfm_tmp, &key_tfm_list,
1823				 key_tfm_list) {
1824		list_del(&key_tfm->key_tfm_list);
1825		if (key_tfm->key_tfm)
1826			crypto_free_blkcipher(key_tfm->key_tfm);
1827		kmem_cache_free(ecryptfs_key_tfm_cache, key_tfm);
1828	}
1829	mutex_unlock(&key_tfm_list_mutex);
1830	return 0;
1831}
1832
1833int
1834ecryptfs_add_new_key_tfm(struct ecryptfs_key_tfm **key_tfm, char *cipher_name,
1835			 size_t key_size)
1836{
1837	struct ecryptfs_key_tfm *tmp_tfm;
1838	int rc = 0;
1839
1840	BUG_ON(!mutex_is_locked(&key_tfm_list_mutex));
1841
1842	tmp_tfm = kmem_cache_alloc(ecryptfs_key_tfm_cache, GFP_KERNEL);
1843	if (key_tfm != NULL)
1844		(*key_tfm) = tmp_tfm;
1845	if (!tmp_tfm) {
1846		rc = -ENOMEM;
1847		printk(KERN_ERR "Error attempting to allocate from "
1848		       "ecryptfs_key_tfm_cache\n");
1849		goto out;
1850	}
1851	mutex_init(&tmp_tfm->key_tfm_mutex);
1852	strncpy(tmp_tfm->cipher_name, cipher_name,
1853		ECRYPTFS_MAX_CIPHER_NAME_SIZE);
1854	tmp_tfm->cipher_name[ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
1855	tmp_tfm->key_size = key_size;
1856	rc = ecryptfs_process_key_cipher(&tmp_tfm->key_tfm,
1857					 tmp_tfm->cipher_name,
1858					 &tmp_tfm->key_size);
1859	if (rc) {
1860		printk(KERN_ERR "Error attempting to initialize key TFM "
1861		       "cipher with name = [%s]; rc = [%d]\n",
1862		       tmp_tfm->cipher_name, rc);
1863		kmem_cache_free(ecryptfs_key_tfm_cache, tmp_tfm);
1864		if (key_tfm != NULL)
1865			(*key_tfm) = NULL;
1866		goto out;
1867	}
1868	list_add(&tmp_tfm->key_tfm_list, &key_tfm_list);
1869out:
1870	return rc;
1871}
1872
1873/**
1874 * ecryptfs_tfm_exists - Search for existing tfm for cipher_name.
1875 * @cipher_name: the name of the cipher to search for
1876 * @key_tfm: set to corresponding tfm if found
1877 *
1878 * Searches for cached key_tfm matching @cipher_name
1879 * Must be called with &key_tfm_list_mutex held
1880 * Returns 1 if found, with @key_tfm set
1881 * Returns 0 if not found, with @key_tfm set to NULL
1882 */
1883int ecryptfs_tfm_exists(char *cipher_name, struct ecryptfs_key_tfm **key_tfm)
1884{
1885	struct ecryptfs_key_tfm *tmp_key_tfm;
1886
1887	BUG_ON(!mutex_is_locked(&key_tfm_list_mutex));
1888
1889	list_for_each_entry(tmp_key_tfm, &key_tfm_list, key_tfm_list) {
1890		if (strcmp(tmp_key_tfm->cipher_name, cipher_name) == 0) {
1891			if (key_tfm)
1892				(*key_tfm) = tmp_key_tfm;
1893			return 1;
1894		}
1895	}
1896	if (key_tfm)
1897		(*key_tfm) = NULL;
1898	return 0;
1899}
1900
1901/**
1902 * ecryptfs_get_tfm_and_mutex_for_cipher_name
1903 *
1904 * @tfm: set to cached tfm found, or new tfm created
1905 * @tfm_mutex: set to mutex for cached tfm found, or new tfm created
1906 * @cipher_name: the name of the cipher to search for and/or add
1907 *
1908 * Sets pointers to @tfm & @tfm_mutex matching @cipher_name.
1909 * Searches for cached item first, and creates new if not found.
1910 * Returns 0 on success, non-zero if adding new cipher failed
1911 */
1912int ecryptfs_get_tfm_and_mutex_for_cipher_name(struct crypto_blkcipher **tfm,
1913					       struct mutex **tfm_mutex,
1914					       char *cipher_name)
1915{
1916	struct ecryptfs_key_tfm *key_tfm;
1917	int rc = 0;
1918
1919	(*tfm) = NULL;
1920	(*tfm_mutex) = NULL;
1921
1922	mutex_lock(&key_tfm_list_mutex);
1923	if (!ecryptfs_tfm_exists(cipher_name, &key_tfm)) {
1924		rc = ecryptfs_add_new_key_tfm(&key_tfm, cipher_name, 0);
1925		if (rc) {
1926			printk(KERN_ERR "Error adding new key_tfm to list; "
1927					"rc = [%d]\n", rc);
1928			goto out;
1929		}
1930	}
1931	(*tfm) = key_tfm->key_tfm;
1932	(*tfm_mutex) = &key_tfm->key_tfm_mutex;
1933out:
1934	mutex_unlock(&key_tfm_list_mutex);
1935	return rc;
1936}
1937
1938/* 64 characters forming a 6-bit target field */
1939static unsigned char *portable_filename_chars = ("-.0123456789ABCD"
1940						 "EFGHIJKLMNOPQRST"
1941						 "UVWXYZabcdefghij"
1942						 "klmnopqrstuvwxyz");
1943
1944/* We could either offset on every reverse map or just pad some 0x00's
1945 * at the front here */
1946static const unsigned char filename_rev_map[] = {
1947	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 7 */
1948	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 15 */
1949	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 23 */
1950	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 31 */
1951	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 39 */
1952	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, /* 47 */
1953	0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, /* 55 */
1954	0x0A, 0x0B, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 63 */
1955	0x00, 0x0C, 0x0D, 0x0E, 0x0F, 0x10, 0x11, 0x12, /* 71 */
1956	0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1A, /* 79 */
1957	0x1B, 0x1C, 0x1D, 0x1E, 0x1F, 0x20, 0x21, 0x22, /* 87 */
1958	0x23, 0x24, 0x25, 0x00, 0x00, 0x00, 0x00, 0x00, /* 95 */
1959	0x00, 0x26, 0x27, 0x28, 0x29, 0x2A, 0x2B, 0x2C, /* 103 */
1960	0x2D, 0x2E, 0x2F, 0x30, 0x31, 0x32, 0x33, 0x34, /* 111 */
1961	0x35, 0x36, 0x37, 0x38, 0x39, 0x3A, 0x3B, 0x3C, /* 119 */
1962	0x3D, 0x3E, 0x3F
1963};
1964
1965/**
1966 * ecryptfs_encode_for_filename
1967 * @dst: Destination location for encoded filename
1968 * @dst_size: Size of the encoded filename in bytes
1969 * @src: Source location for the filename to encode
1970 * @src_size: Size of the source in bytes
1971 */
1972void ecryptfs_encode_for_filename(unsigned char *dst, size_t *dst_size,
1973				  unsigned char *src, size_t src_size)
1974{
1975	size_t num_blocks;
1976	size_t block_num = 0;
1977	size_t dst_offset = 0;
1978	unsigned char last_block[3];
1979
1980	if (src_size == 0) {
1981		(*dst_size) = 0;
1982		goto out;
1983	}
1984	num_blocks = (src_size / 3);
1985	if ((src_size % 3) == 0) {
1986		memcpy(last_block, (&src[src_size - 3]), 3);
1987	} else {
1988		num_blocks++;
1989		last_block[2] = 0x00;
1990		switch (src_size % 3) {
1991		case 1:
1992			last_block[0] = src[src_size - 1];
1993			last_block[1] = 0x00;
1994			break;
1995		case 2:
1996			last_block[0] = src[src_size - 2];
1997			last_block[1] = src[src_size - 1];
1998		}
1999	}
2000	(*dst_size) = (num_blocks * 4);
2001	if (!dst)
2002		goto out;
2003	while (block_num < num_blocks) {
2004		unsigned char *src_block;
2005		unsigned char dst_block[4];
2006
2007		if (block_num == (num_blocks - 1))
2008			src_block = last_block;
2009		else
2010			src_block = &src[block_num * 3];
2011		dst_block[0] = ((src_block[0] >> 2) & 0x3F);
2012		dst_block[1] = (((src_block[0] << 4) & 0x30)
2013				| ((src_block[1] >> 4) & 0x0F));
2014		dst_block[2] = (((src_block[1] << 2) & 0x3C)
2015				| ((src_block[2] >> 6) & 0x03));
2016		dst_block[3] = (src_block[2] & 0x3F);
2017		dst[dst_offset++] = portable_filename_chars[dst_block[0]];
2018		dst[dst_offset++] = portable_filename_chars[dst_block[1]];
2019		dst[dst_offset++] = portable_filename_chars[dst_block[2]];
2020		dst[dst_offset++] = portable_filename_chars[dst_block[3]];
2021		block_num++;
2022	}
2023out:
2024	return;
2025}
2026
 
 
 
 
 
 
 
 
 
 
 
2027/**
2028 * ecryptfs_decode_from_filename
2029 * @dst: If NULL, this function only sets @dst_size and returns. If
2030 *       non-NULL, this function decodes the encoded octets in @src
2031 *       into the memory that @dst points to.
2032 * @dst_size: Set to the size of the decoded string.
2033 * @src: The encoded set of octets to decode.
2034 * @src_size: The size of the encoded set of octets to decode.
2035 */
2036static void
2037ecryptfs_decode_from_filename(unsigned char *dst, size_t *dst_size,
2038			      const unsigned char *src, size_t src_size)
2039{
2040	u8 current_bit_offset = 0;
2041	size_t src_byte_offset = 0;
2042	size_t dst_byte_offset = 0;
2043
2044	if (dst == NULL) {
2045		/* Not exact; conservatively long. Every block of 4
2046		 * encoded characters decodes into a block of 3
2047		 * decoded characters. This segment of code provides
2048		 * the caller with the maximum amount of allocated
2049		 * space that @dst will need to point to in a
2050		 * subsequent call. */
2051		(*dst_size) = (((src_size + 1) * 3) / 4);
2052		goto out;
2053	}
2054	while (src_byte_offset < src_size) {
2055		unsigned char src_byte =
2056				filename_rev_map[(int)src[src_byte_offset]];
2057
2058		switch (current_bit_offset) {
2059		case 0:
2060			dst[dst_byte_offset] = (src_byte << 2);
2061			current_bit_offset = 6;
2062			break;
2063		case 6:
2064			dst[dst_byte_offset++] |= (src_byte >> 4);
2065			dst[dst_byte_offset] = ((src_byte & 0xF)
2066						 << 4);
2067			current_bit_offset = 4;
2068			break;
2069		case 4:
2070			dst[dst_byte_offset++] |= (src_byte >> 2);
2071			dst[dst_byte_offset] = (src_byte << 6);
2072			current_bit_offset = 2;
2073			break;
2074		case 2:
2075			dst[dst_byte_offset++] |= (src_byte);
2076			dst[dst_byte_offset] = 0;
2077			current_bit_offset = 0;
2078			break;
2079		}
2080		src_byte_offset++;
2081	}
2082	(*dst_size) = dst_byte_offset;
2083out:
2084	return;
2085}
2086
2087/**
2088 * ecryptfs_encrypt_and_encode_filename - converts a plaintext file name to cipher text
2089 * @crypt_stat: The crypt_stat struct associated with the file anem to encode
2090 * @name: The plaintext name
2091 * @length: The length of the plaintext
2092 * @encoded_name: The encypted name
2093 *
2094 * Encrypts and encodes a filename into something that constitutes a
2095 * valid filename for a filesystem, with printable characters.
2096 *
2097 * We assume that we have a properly initialized crypto context,
2098 * pointed to by crypt_stat->tfm.
2099 *
2100 * Returns zero on success; non-zero on otherwise
2101 */
2102int ecryptfs_encrypt_and_encode_filename(
2103	char **encoded_name,
2104	size_t *encoded_name_size,
2105	struct ecryptfs_crypt_stat *crypt_stat,
2106	struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
2107	const char *name, size_t name_size)
2108{
2109	size_t encoded_name_no_prefix_size;
2110	int rc = 0;
2111
2112	(*encoded_name) = NULL;
2113	(*encoded_name_size) = 0;
2114	if ((crypt_stat && (crypt_stat->flags & ECRYPTFS_ENCRYPT_FILENAMES))
2115	    || (mount_crypt_stat && (mount_crypt_stat->flags
2116				     & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES))) {
2117		struct ecryptfs_filename *filename;
2118
2119		filename = kzalloc(sizeof(*filename), GFP_KERNEL);
2120		if (!filename) {
2121			printk(KERN_ERR "%s: Out of memory whilst attempting "
2122			       "to kzalloc [%zd] bytes\n", __func__,
2123			       sizeof(*filename));
2124			rc = -ENOMEM;
2125			goto out;
2126		}
2127		filename->filename = (char *)name;
2128		filename->filename_size = name_size;
2129		rc = ecryptfs_encrypt_filename(filename, crypt_stat,
2130					       mount_crypt_stat);
2131		if (rc) {
2132			printk(KERN_ERR "%s: Error attempting to encrypt "
2133			       "filename; rc = [%d]\n", __func__, rc);
2134			kfree(filename);
2135			goto out;
2136		}
2137		ecryptfs_encode_for_filename(
2138			NULL, &encoded_name_no_prefix_size,
2139			filename->encrypted_filename,
2140			filename->encrypted_filename_size);
2141		if ((crypt_stat && (crypt_stat->flags
2142				    & ECRYPTFS_ENCFN_USE_MOUNT_FNEK))
2143		    || (mount_crypt_stat
2144			&& (mount_crypt_stat->flags
2145			    & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK)))
2146			(*encoded_name_size) =
2147				(ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE
2148				 + encoded_name_no_prefix_size);
2149		else
2150			(*encoded_name_size) =
2151				(ECRYPTFS_FEK_ENCRYPTED_FILENAME_PREFIX_SIZE
2152				 + encoded_name_no_prefix_size);
2153		(*encoded_name) = kmalloc((*encoded_name_size) + 1, GFP_KERNEL);
2154		if (!(*encoded_name)) {
2155			printk(KERN_ERR "%s: Out of memory whilst attempting "
2156			       "to kzalloc [%zd] bytes\n", __func__,
2157			       (*encoded_name_size));
2158			rc = -ENOMEM;
2159			kfree(filename->encrypted_filename);
2160			kfree(filename);
2161			goto out;
2162		}
2163		if ((crypt_stat && (crypt_stat->flags
2164				    & ECRYPTFS_ENCFN_USE_MOUNT_FNEK))
2165		    || (mount_crypt_stat
2166			&& (mount_crypt_stat->flags
2167			    & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK))) {
2168			memcpy((*encoded_name),
2169			       ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX,
2170			       ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE);
2171			ecryptfs_encode_for_filename(
2172			    ((*encoded_name)
2173			     + ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE),
2174			    &encoded_name_no_prefix_size,
2175			    filename->encrypted_filename,
2176			    filename->encrypted_filename_size);
2177			(*encoded_name_size) =
2178				(ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE
2179				 + encoded_name_no_prefix_size);
2180			(*encoded_name)[(*encoded_name_size)] = '\0';
2181		} else {
2182			rc = -EOPNOTSUPP;
2183		}
2184		if (rc) {
2185			printk(KERN_ERR "%s: Error attempting to encode "
2186			       "encrypted filename; rc = [%d]\n", __func__,
2187			       rc);
2188			kfree((*encoded_name));
2189			(*encoded_name) = NULL;
2190			(*encoded_name_size) = 0;
2191		}
2192		kfree(filename->encrypted_filename);
2193		kfree(filename);
2194	} else {
2195		rc = ecryptfs_copy_filename(encoded_name,
2196					    encoded_name_size,
2197					    name, name_size);
2198	}
2199out:
2200	return rc;
2201}
2202
 
 
 
 
 
 
 
 
 
 
2203/**
2204 * ecryptfs_decode_and_decrypt_filename - converts the encoded cipher text name to decoded plaintext
2205 * @plaintext_name: The plaintext name
2206 * @plaintext_name_size: The plaintext name size
2207 * @ecryptfs_dir_dentry: eCryptfs directory dentry
2208 * @name: The filename in cipher text
2209 * @name_size: The cipher text name size
2210 *
2211 * Decrypts and decodes the filename.
2212 *
2213 * Returns zero on error; non-zero otherwise
2214 */
2215int ecryptfs_decode_and_decrypt_filename(char **plaintext_name,
2216					 size_t *plaintext_name_size,
2217					 struct dentry *ecryptfs_dir_dentry,
2218					 const char *name, size_t name_size)
2219{
2220	struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
2221		&ecryptfs_superblock_to_private(
2222			ecryptfs_dir_dentry->d_sb)->mount_crypt_stat;
2223	char *decoded_name;
2224	size_t decoded_name_size;
2225	size_t packet_size;
2226	int rc = 0;
2227
2228	if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
2229	    && !(mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
2230	    && (name_size > ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE)
2231	    && (strncmp(name, ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX,
2232			ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE) == 0)) {
2233		const char *orig_name = name;
2234		size_t orig_name_size = name_size;
 
 
 
 
 
 
 
 
2235
2236		name += ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE;
2237		name_size -= ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE;
2238		ecryptfs_decode_from_filename(NULL, &decoded_name_size,
2239					      name, name_size);
2240		decoded_name = kmalloc(decoded_name_size, GFP_KERNEL);
2241		if (!decoded_name) {
2242			printk(KERN_ERR "%s: Out of memory whilst attempting "
2243			       "to kmalloc [%zd] bytes\n", __func__,
2244			       decoded_name_size);
2245			rc = -ENOMEM;
2246			goto out;
2247		}
2248		ecryptfs_decode_from_filename(decoded_name, &decoded_name_size,
2249					      name, name_size);
2250		rc = ecryptfs_parse_tag_70_packet(plaintext_name,
2251						  plaintext_name_size,
2252						  &packet_size,
2253						  mount_crypt_stat,
2254						  decoded_name,
2255						  decoded_name_size);
2256		if (rc) {
2257			printk(KERN_INFO "%s: Could not parse tag 70 packet "
2258			       "from filename; copying through filename "
2259			       "as-is\n", __func__);
2260			rc = ecryptfs_copy_filename(plaintext_name,
2261						    plaintext_name_size,
2262						    orig_name, orig_name_size);
2263			goto out_free;
2264		}
2265	} else {
2266		rc = ecryptfs_copy_filename(plaintext_name,
2267					    plaintext_name_size,
2268					    name, name_size);
2269		goto out;
2270	}
2271out_free:
2272	kfree(decoded_name);
2273out:
2274	return rc;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2275}