1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * eCryptfs: Linux filesystem encryption layer
5 * Copyright (C) 1997-2004 Erez Zadok
6 * Copyright (C) 2001-2004 Stony Brook University
7 * Copyright (C) 2004-2007 International Business Machines Corp.
8 * Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
9 * Michael C. Thompson <mcthomps@us.ibm.com>
12 #include <crypto/hash.h>
13 #include <crypto/skcipher.h>
15 #include <linux/mount.h>
16 #include <linux/pagemap.h>
17 #include <linux/random.h>
18 #include <linux/compiler.h>
19 #include <linux/key.h>
20 #include <linux/namei.h>
21 #include <linux/file.h>
22 #include <linux/scatterlist.h>
23 #include <linux/slab.h>
24 #include <asm/unaligned.h>
25 #include <linux/kernel.h>
26 #include <linux/xattr.h>
27 #include "ecryptfs_kernel.h"
34 * @dst: Buffer to take the bytes from src hex; must be at least of
36 * @src: Buffer to be converted from a hex string representation to raw value
37 * @dst_size: size of dst buffer, or number of hex characters pairs to convert
39 void ecryptfs_from_hex(char *dst, char *src, int dst_size)
44 for (x = 0; x < dst_size; x++) {
46 tmp[1] = src[x * 2 + 1];
47 dst[x] = (unsigned char)simple_strtol(tmp, NULL, 16);
52 * ecryptfs_calculate_md5 - calculates the md5 of @src
53 * @dst: Pointer to 16 bytes of allocated memory
54 * @crypt_stat: Pointer to crypt_stat struct for the current inode
55 * @src: Data to be md5'd
56 * @len: Length of @src
58 * Uses the allocated crypto context that crypt_stat references to
59 * generate the MD5 sum of the contents of src.
61 static int ecryptfs_calculate_md5(char *dst,
62 struct ecryptfs_crypt_stat *crypt_stat,
65 int rc = crypto_shash_tfm_digest(crypt_stat->hash_tfm, src, len, dst);
69 "%s: Error computing crypto hash; rc = [%d]\n",
77 static int ecryptfs_crypto_api_algify_cipher_name(char **algified_name,
79 char *chaining_modifier)
81 int cipher_name_len = strlen(cipher_name);
82 int chaining_modifier_len = strlen(chaining_modifier);
83 int algified_name_len;
86 algified_name_len = (chaining_modifier_len + cipher_name_len + 3);
87 (*algified_name) = kmalloc(algified_name_len, GFP_KERNEL);
88 if (!(*algified_name)) {
92 snprintf((*algified_name), algified_name_len, "%s(%s)",
93 chaining_modifier, cipher_name);
101 * @iv: destination for the derived iv vale
102 * @crypt_stat: Pointer to crypt_stat struct for the current inode
103 * @offset: Offset of the extent whose IV we are to derive
105 * Generate the initialization vector from the given root IV and page
108 * Returns zero on success; non-zero on error.
110 int ecryptfs_derive_iv(char *iv, struct ecryptfs_crypt_stat *crypt_stat,
114 char dst[MD5_DIGEST_SIZE];
115 char src[ECRYPTFS_MAX_IV_BYTES + 16];
117 if (unlikely(ecryptfs_verbosity > 0)) {
118 ecryptfs_printk(KERN_DEBUG, "root iv:\n");
119 ecryptfs_dump_hex(crypt_stat->root_iv, crypt_stat->iv_bytes);
121 /* TODO: It is probably secure to just cast the least
122 * significant bits of the root IV into an unsigned long and
123 * add the offset to that rather than go through all this
124 * hashing business. -Halcrow */
125 memcpy(src, crypt_stat->root_iv, crypt_stat->iv_bytes);
126 memset((src + crypt_stat->iv_bytes), 0, 16);
127 snprintf((src + crypt_stat->iv_bytes), 16, "%lld", offset);
128 if (unlikely(ecryptfs_verbosity > 0)) {
129 ecryptfs_printk(KERN_DEBUG, "source:\n");
130 ecryptfs_dump_hex(src, (crypt_stat->iv_bytes + 16));
132 rc = ecryptfs_calculate_md5(dst, crypt_stat, src,
133 (crypt_stat->iv_bytes + 16));
135 ecryptfs_printk(KERN_WARNING, "Error attempting to compute "
136 "MD5 while generating IV for a page\n");
139 memcpy(iv, dst, crypt_stat->iv_bytes);
140 if (unlikely(ecryptfs_verbosity > 0)) {
141 ecryptfs_printk(KERN_DEBUG, "derived iv:\n");
142 ecryptfs_dump_hex(iv, crypt_stat->iv_bytes);
149 * ecryptfs_init_crypt_stat
150 * @crypt_stat: Pointer to the crypt_stat struct to initialize.
152 * Initialize the crypt_stat structure.
154 int ecryptfs_init_crypt_stat(struct ecryptfs_crypt_stat *crypt_stat)
156 struct crypto_shash *tfm;
159 tfm = crypto_alloc_shash(ECRYPTFS_DEFAULT_HASH, 0, 0);
162 ecryptfs_printk(KERN_ERR, "Error attempting to "
163 "allocate crypto context; rc = [%d]\n",
168 memset((void *)crypt_stat, 0, sizeof(struct ecryptfs_crypt_stat));
169 INIT_LIST_HEAD(&crypt_stat->keysig_list);
170 mutex_init(&crypt_stat->keysig_list_mutex);
171 mutex_init(&crypt_stat->cs_mutex);
172 mutex_init(&crypt_stat->cs_tfm_mutex);
173 crypt_stat->hash_tfm = tfm;
174 crypt_stat->flags |= ECRYPTFS_STRUCT_INITIALIZED;
180 * ecryptfs_destroy_crypt_stat
181 * @crypt_stat: Pointer to the crypt_stat struct to initialize.
183 * Releases all memory associated with a crypt_stat struct.
185 void ecryptfs_destroy_crypt_stat(struct ecryptfs_crypt_stat *crypt_stat)
187 struct ecryptfs_key_sig *key_sig, *key_sig_tmp;
189 crypto_free_skcipher(crypt_stat->tfm);
190 crypto_free_shash(crypt_stat->hash_tfm);
191 list_for_each_entry_safe(key_sig, key_sig_tmp,
192 &crypt_stat->keysig_list, crypt_stat_list) {
193 list_del(&key_sig->crypt_stat_list);
194 kmem_cache_free(ecryptfs_key_sig_cache, key_sig);
196 memset(crypt_stat, 0, sizeof(struct ecryptfs_crypt_stat));
199 void ecryptfs_destroy_mount_crypt_stat(
200 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
202 struct ecryptfs_global_auth_tok *auth_tok, *auth_tok_tmp;
204 if (!(mount_crypt_stat->flags & ECRYPTFS_MOUNT_CRYPT_STAT_INITIALIZED))
206 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
207 list_for_each_entry_safe(auth_tok, auth_tok_tmp,
208 &mount_crypt_stat->global_auth_tok_list,
209 mount_crypt_stat_list) {
210 list_del(&auth_tok->mount_crypt_stat_list);
211 if (!(auth_tok->flags & ECRYPTFS_AUTH_TOK_INVALID))
212 key_put(auth_tok->global_auth_tok_key);
213 kmem_cache_free(ecryptfs_global_auth_tok_cache, auth_tok);
215 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
216 memset(mount_crypt_stat, 0, sizeof(struct ecryptfs_mount_crypt_stat));
220 * virt_to_scatterlist
221 * @addr: Virtual address
222 * @size: Size of data; should be an even multiple of the block size
223 * @sg: Pointer to scatterlist array; set to NULL to obtain only
224 * the number of scatterlist structs required in array
225 * @sg_size: Max array size
227 * Fills in a scatterlist array with page references for a passed
230 * Returns the number of scatterlist structs in array used
232 int virt_to_scatterlist(const void *addr, int size, struct scatterlist *sg,
238 int remainder_of_page;
240 sg_init_table(sg, sg_size);
242 while (size > 0 && i < sg_size) {
243 pg = virt_to_page(addr);
244 offset = offset_in_page(addr);
245 sg_set_page(&sg[i], pg, 0, offset);
246 remainder_of_page = PAGE_SIZE - offset;
247 if (size >= remainder_of_page) {
248 sg[i].length = remainder_of_page;
249 addr += remainder_of_page;
250 size -= remainder_of_page;
263 struct extent_crypt_result {
264 struct completion completion;
268 static void extent_crypt_complete(struct crypto_async_request *req, int rc)
270 struct extent_crypt_result *ecr = req->data;
272 if (rc == -EINPROGRESS)
276 complete(&ecr->completion);
281 * @crypt_stat: Pointer to the crypt_stat struct to initialize.
282 * @dst_sg: Destination of the data after performing the crypto operation
283 * @src_sg: Data to be encrypted or decrypted
284 * @size: Length of data
286 * @op: ENCRYPT or DECRYPT to indicate the desired operation
288 * Returns the number of bytes encrypted or decrypted; negative value on error
290 static int crypt_scatterlist(struct ecryptfs_crypt_stat *crypt_stat,
291 struct scatterlist *dst_sg,
292 struct scatterlist *src_sg, int size,
293 unsigned char *iv, int op)
295 struct skcipher_request *req = NULL;
296 struct extent_crypt_result ecr;
299 if (!crypt_stat || !crypt_stat->tfm
300 || !(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED))
303 if (unlikely(ecryptfs_verbosity > 0)) {
304 ecryptfs_printk(KERN_DEBUG, "Key size [%zd]; key:\n",
305 crypt_stat->key_size);
306 ecryptfs_dump_hex(crypt_stat->key,
307 crypt_stat->key_size);
310 init_completion(&ecr.completion);
312 mutex_lock(&crypt_stat->cs_tfm_mutex);
313 req = skcipher_request_alloc(crypt_stat->tfm, GFP_NOFS);
315 mutex_unlock(&crypt_stat->cs_tfm_mutex);
320 skcipher_request_set_callback(req,
321 CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
322 extent_crypt_complete, &ecr);
323 /* Consider doing this once, when the file is opened */
324 if (!(crypt_stat->flags & ECRYPTFS_KEY_SET)) {
325 rc = crypto_skcipher_setkey(crypt_stat->tfm, crypt_stat->key,
326 crypt_stat->key_size);
328 ecryptfs_printk(KERN_ERR,
329 "Error setting key; rc = [%d]\n",
331 mutex_unlock(&crypt_stat->cs_tfm_mutex);
335 crypt_stat->flags |= ECRYPTFS_KEY_SET;
337 mutex_unlock(&crypt_stat->cs_tfm_mutex);
338 skcipher_request_set_crypt(req, src_sg, dst_sg, size, iv);
339 rc = op == ENCRYPT ? crypto_skcipher_encrypt(req) :
340 crypto_skcipher_decrypt(req);
341 if (rc == -EINPROGRESS || rc == -EBUSY) {
342 struct extent_crypt_result *ecr = req->base.data;
344 wait_for_completion(&ecr->completion);
346 reinit_completion(&ecr->completion);
349 skcipher_request_free(req);
354 * lower_offset_for_page
356 * Convert an eCryptfs page index into a lower byte offset
358 static loff_t lower_offset_for_page(struct ecryptfs_crypt_stat *crypt_stat,
361 return ecryptfs_lower_header_size(crypt_stat) +
362 ((loff_t)page->index << PAGE_SHIFT);
367 * @crypt_stat: crypt_stat containing cryptographic context for the
368 * encryption operation
369 * @dst_page: The page to write the result into
370 * @src_page: The page to read from
371 * @extent_offset: Page extent offset for use in generating IV
372 * @op: ENCRYPT or DECRYPT to indicate the desired operation
374 * Encrypts or decrypts one extent of data.
376 * Return zero on success; non-zero otherwise
378 static int crypt_extent(struct ecryptfs_crypt_stat *crypt_stat,
379 struct page *dst_page,
380 struct page *src_page,
381 unsigned long extent_offset, int op)
383 pgoff_t page_index = op == ENCRYPT ? src_page->index : dst_page->index;
385 char extent_iv[ECRYPTFS_MAX_IV_BYTES];
386 struct scatterlist src_sg, dst_sg;
387 size_t extent_size = crypt_stat->extent_size;
390 extent_base = (((loff_t)page_index) * (PAGE_SIZE / extent_size));
391 rc = ecryptfs_derive_iv(extent_iv, crypt_stat,
392 (extent_base + extent_offset));
394 ecryptfs_printk(KERN_ERR, "Error attempting to derive IV for "
395 "extent [0x%.16llx]; rc = [%d]\n",
396 (unsigned long long)(extent_base + extent_offset), rc);
400 sg_init_table(&src_sg, 1);
401 sg_init_table(&dst_sg, 1);
403 sg_set_page(&src_sg, src_page, extent_size,
404 extent_offset * extent_size);
405 sg_set_page(&dst_sg, dst_page, extent_size,
406 extent_offset * extent_size);
408 rc = crypt_scatterlist(crypt_stat, &dst_sg, &src_sg, extent_size,
411 printk(KERN_ERR "%s: Error attempting to crypt page with "
412 "page_index = [%ld], extent_offset = [%ld]; "
413 "rc = [%d]\n", __func__, page_index, extent_offset, rc);
422 * ecryptfs_encrypt_page
423 * @page: Page mapped from the eCryptfs inode for the file; contains
424 * decrypted content that needs to be encrypted (to a temporary
425 * page; not in place) and written out to the lower file
427 * Encrypt an eCryptfs page. This is done on a per-extent basis. Note
428 * that eCryptfs pages may straddle the lower pages -- for instance,
429 * if the file was created on a machine with an 8K page size
430 * (resulting in an 8K header), and then the file is copied onto a
431 * host with a 32K page size, then when reading page 0 of the eCryptfs
432 * file, 24K of page 0 of the lower file will be read and decrypted,
433 * and then 8K of page 1 of the lower file will be read and decrypted.
435 * Returns zero on success; negative on error
437 int ecryptfs_encrypt_page(struct page *page)
439 struct inode *ecryptfs_inode;
440 struct ecryptfs_crypt_stat *crypt_stat;
441 char *enc_extent_virt;
442 struct page *enc_extent_page = NULL;
443 loff_t extent_offset;
447 ecryptfs_inode = page->mapping->host;
449 &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat);
450 BUG_ON(!(crypt_stat->flags & ECRYPTFS_ENCRYPTED));
451 enc_extent_page = alloc_page(GFP_USER);
452 if (!enc_extent_page) {
454 ecryptfs_printk(KERN_ERR, "Error allocating memory for "
455 "encrypted extent\n");
459 for (extent_offset = 0;
460 extent_offset < (PAGE_SIZE / crypt_stat->extent_size);
462 rc = crypt_extent(crypt_stat, enc_extent_page, page,
463 extent_offset, ENCRYPT);
465 printk(KERN_ERR "%s: Error encrypting extent; "
466 "rc = [%d]\n", __func__, rc);
471 lower_offset = lower_offset_for_page(crypt_stat, page);
472 enc_extent_virt = kmap(enc_extent_page);
473 rc = ecryptfs_write_lower(ecryptfs_inode, enc_extent_virt, lower_offset,
475 kunmap(enc_extent_page);
477 ecryptfs_printk(KERN_ERR,
478 "Error attempting to write lower page; rc = [%d]\n",
484 if (enc_extent_page) {
485 __free_page(enc_extent_page);
491 * ecryptfs_decrypt_page
492 * @page: Page mapped from the eCryptfs inode for the file; data read
493 * and decrypted from the lower file will be written into this
496 * Decrypt an eCryptfs page. This is done on a per-extent basis. Note
497 * that eCryptfs pages may straddle the lower pages -- for instance,
498 * if the file was created on a machine with an 8K page size
499 * (resulting in an 8K header), and then the file is copied onto a
500 * host with a 32K page size, then when reading page 0 of the eCryptfs
501 * file, 24K of page 0 of the lower file will be read and decrypted,
502 * and then 8K of page 1 of the lower file will be read and decrypted.
504 * Returns zero on success; negative on error
506 int ecryptfs_decrypt_page(struct page *page)
508 struct inode *ecryptfs_inode;
509 struct ecryptfs_crypt_stat *crypt_stat;
511 unsigned long extent_offset;
515 ecryptfs_inode = page->mapping->host;
517 &(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat);
518 BUG_ON(!(crypt_stat->flags & ECRYPTFS_ENCRYPTED));
520 lower_offset = lower_offset_for_page(crypt_stat, page);
521 page_virt = kmap(page);
522 rc = ecryptfs_read_lower(page_virt, lower_offset, PAGE_SIZE,
526 ecryptfs_printk(KERN_ERR,
527 "Error attempting to read lower page; rc = [%d]\n",
532 for (extent_offset = 0;
533 extent_offset < (PAGE_SIZE / crypt_stat->extent_size);
535 rc = crypt_extent(crypt_stat, page, page,
536 extent_offset, DECRYPT);
538 printk(KERN_ERR "%s: Error decrypting extent; "
539 "rc = [%d]\n", __func__, rc);
547 #define ECRYPTFS_MAX_SCATTERLIST_LEN 4
550 * ecryptfs_init_crypt_ctx
551 * @crypt_stat: Uninitialized crypt stats structure
553 * Initialize the crypto context.
555 * TODO: Performance: Keep a cache of initialized cipher contexts;
556 * only init if needed
558 int ecryptfs_init_crypt_ctx(struct ecryptfs_crypt_stat *crypt_stat)
563 ecryptfs_printk(KERN_DEBUG,
564 "Initializing cipher [%s]; strlen = [%d]; "
565 "key_size_bits = [%zd]\n",
566 crypt_stat->cipher, (int)strlen(crypt_stat->cipher),
567 crypt_stat->key_size << 3);
568 mutex_lock(&crypt_stat->cs_tfm_mutex);
569 if (crypt_stat->tfm) {
573 rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name,
574 crypt_stat->cipher, "cbc");
577 crypt_stat->tfm = crypto_alloc_skcipher(full_alg_name, 0, 0);
578 if (IS_ERR(crypt_stat->tfm)) {
579 rc = PTR_ERR(crypt_stat->tfm);
580 crypt_stat->tfm = NULL;
581 ecryptfs_printk(KERN_ERR, "cryptfs: init_crypt_ctx(): "
582 "Error initializing cipher [%s]\n",
586 crypto_skcipher_set_flags(crypt_stat->tfm,
587 CRYPTO_TFM_REQ_FORBID_WEAK_KEYS);
590 kfree(full_alg_name);
592 mutex_unlock(&crypt_stat->cs_tfm_mutex);
596 static void set_extent_mask_and_shift(struct ecryptfs_crypt_stat *crypt_stat)
600 crypt_stat->extent_mask = 0xFFFFFFFF;
601 crypt_stat->extent_shift = 0;
602 if (crypt_stat->extent_size == 0)
604 extent_size_tmp = crypt_stat->extent_size;
605 while ((extent_size_tmp & 0x01) == 0) {
606 extent_size_tmp >>= 1;
607 crypt_stat->extent_mask <<= 1;
608 crypt_stat->extent_shift++;
612 void ecryptfs_set_default_sizes(struct ecryptfs_crypt_stat *crypt_stat)
614 /* Default values; may be overwritten as we are parsing the
616 crypt_stat->extent_size = ECRYPTFS_DEFAULT_EXTENT_SIZE;
617 set_extent_mask_and_shift(crypt_stat);
618 crypt_stat->iv_bytes = ECRYPTFS_DEFAULT_IV_BYTES;
619 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
620 crypt_stat->metadata_size = ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
622 if (PAGE_SIZE <= ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE)
623 crypt_stat->metadata_size =
624 ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
626 crypt_stat->metadata_size = PAGE_SIZE;
631 * ecryptfs_compute_root_iv
633 * On error, sets the root IV to all 0's.
635 int ecryptfs_compute_root_iv(struct ecryptfs_crypt_stat *crypt_stat)
638 char dst[MD5_DIGEST_SIZE];
640 BUG_ON(crypt_stat->iv_bytes > MD5_DIGEST_SIZE);
641 BUG_ON(crypt_stat->iv_bytes <= 0);
642 if (!(crypt_stat->flags & ECRYPTFS_KEY_VALID)) {
644 ecryptfs_printk(KERN_WARNING, "Session key not valid; "
645 "cannot generate root IV\n");
648 rc = ecryptfs_calculate_md5(dst, crypt_stat, crypt_stat->key,
649 crypt_stat->key_size);
651 ecryptfs_printk(KERN_WARNING, "Error attempting to compute "
652 "MD5 while generating root IV\n");
655 memcpy(crypt_stat->root_iv, dst, crypt_stat->iv_bytes);
658 memset(crypt_stat->root_iv, 0, crypt_stat->iv_bytes);
659 crypt_stat->flags |= ECRYPTFS_SECURITY_WARNING;
664 static void ecryptfs_generate_new_key(struct ecryptfs_crypt_stat *crypt_stat)
666 get_random_bytes(crypt_stat->key, crypt_stat->key_size);
667 crypt_stat->flags |= ECRYPTFS_KEY_VALID;
668 ecryptfs_compute_root_iv(crypt_stat);
669 if (unlikely(ecryptfs_verbosity > 0)) {
670 ecryptfs_printk(KERN_DEBUG, "Generated new session key:\n");
671 ecryptfs_dump_hex(crypt_stat->key,
672 crypt_stat->key_size);
677 * ecryptfs_copy_mount_wide_flags_to_inode_flags
678 * @crypt_stat: The inode's cryptographic context
679 * @mount_crypt_stat: The mount point's cryptographic context
681 * This function propagates the mount-wide flags to individual inode
684 static void ecryptfs_copy_mount_wide_flags_to_inode_flags(
685 struct ecryptfs_crypt_stat *crypt_stat,
686 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
688 if (mount_crypt_stat->flags & ECRYPTFS_XATTR_METADATA_ENABLED)
689 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
690 if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
691 crypt_stat->flags |= ECRYPTFS_VIEW_AS_ENCRYPTED;
692 if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) {
693 crypt_stat->flags |= ECRYPTFS_ENCRYPT_FILENAMES;
694 if (mount_crypt_stat->flags
695 & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK)
696 crypt_stat->flags |= ECRYPTFS_ENCFN_USE_MOUNT_FNEK;
697 else if (mount_crypt_stat->flags
698 & ECRYPTFS_GLOBAL_ENCFN_USE_FEK)
699 crypt_stat->flags |= ECRYPTFS_ENCFN_USE_FEK;
703 static int ecryptfs_copy_mount_wide_sigs_to_inode_sigs(
704 struct ecryptfs_crypt_stat *crypt_stat,
705 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
707 struct ecryptfs_global_auth_tok *global_auth_tok;
710 mutex_lock(&crypt_stat->keysig_list_mutex);
711 mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
713 list_for_each_entry(global_auth_tok,
714 &mount_crypt_stat->global_auth_tok_list,
715 mount_crypt_stat_list) {
716 if (global_auth_tok->flags & ECRYPTFS_AUTH_TOK_FNEK)
718 rc = ecryptfs_add_keysig(crypt_stat, global_auth_tok->sig);
720 printk(KERN_ERR "Error adding keysig; rc = [%d]\n", rc);
726 mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
727 mutex_unlock(&crypt_stat->keysig_list_mutex);
732 * ecryptfs_set_default_crypt_stat_vals
733 * @crypt_stat: The inode's cryptographic context
734 * @mount_crypt_stat: The mount point's cryptographic context
736 * Default values in the event that policy does not override them.
738 static void ecryptfs_set_default_crypt_stat_vals(
739 struct ecryptfs_crypt_stat *crypt_stat,
740 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
742 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
744 ecryptfs_set_default_sizes(crypt_stat);
745 strcpy(crypt_stat->cipher, ECRYPTFS_DEFAULT_CIPHER);
746 crypt_stat->key_size = ECRYPTFS_DEFAULT_KEY_BYTES;
747 crypt_stat->flags &= ~(ECRYPTFS_KEY_VALID);
748 crypt_stat->file_version = ECRYPTFS_FILE_VERSION;
749 crypt_stat->mount_crypt_stat = mount_crypt_stat;
753 * ecryptfs_new_file_context
754 * @ecryptfs_inode: The eCryptfs inode
756 * If the crypto context for the file has not yet been established,
757 * this is where we do that. Establishing a new crypto context
758 * involves the following decisions:
759 * - What cipher to use?
760 * - What set of authentication tokens to use?
761 * Here we just worry about getting enough information into the
762 * authentication tokens so that we know that they are available.
763 * We associate the available authentication tokens with the new file
764 * via the set of signatures in the crypt_stat struct. Later, when
765 * the headers are actually written out, we may again defer to
766 * userspace to perform the encryption of the session key; for the
767 * foreseeable future, this will be the case with public key packets.
769 * Returns zero on success; non-zero otherwise
771 int ecryptfs_new_file_context(struct inode *ecryptfs_inode)
773 struct ecryptfs_crypt_stat *crypt_stat =
774 &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
775 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
776 &ecryptfs_superblock_to_private(
777 ecryptfs_inode->i_sb)->mount_crypt_stat;
781 ecryptfs_set_default_crypt_stat_vals(crypt_stat, mount_crypt_stat);
782 crypt_stat->flags |= (ECRYPTFS_ENCRYPTED | ECRYPTFS_KEY_VALID);
783 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
785 rc = ecryptfs_copy_mount_wide_sigs_to_inode_sigs(crypt_stat,
788 printk(KERN_ERR "Error attempting to copy mount-wide key sigs "
789 "to the inode key sigs; rc = [%d]\n", rc);
793 strlen(mount_crypt_stat->global_default_cipher_name);
794 memcpy(crypt_stat->cipher,
795 mount_crypt_stat->global_default_cipher_name,
797 crypt_stat->cipher[cipher_name_len] = '\0';
798 crypt_stat->key_size =
799 mount_crypt_stat->global_default_cipher_key_size;
800 ecryptfs_generate_new_key(crypt_stat);
801 rc = ecryptfs_init_crypt_ctx(crypt_stat);
803 ecryptfs_printk(KERN_ERR, "Error initializing cryptographic "
804 "context for cipher [%s]: rc = [%d]\n",
805 crypt_stat->cipher, rc);
811 * ecryptfs_validate_marker - check for the ecryptfs marker
812 * @data: The data block in which to check
814 * Returns zero if marker found; -EINVAL if not found
816 static int ecryptfs_validate_marker(char *data)
820 m_1 = get_unaligned_be32(data);
821 m_2 = get_unaligned_be32(data + 4);
822 if ((m_1 ^ MAGIC_ECRYPTFS_MARKER) == m_2)
824 ecryptfs_printk(KERN_DEBUG, "m_1 = [0x%.8x]; m_2 = [0x%.8x]; "
825 "MAGIC_ECRYPTFS_MARKER = [0x%.8x]\n", m_1, m_2,
826 MAGIC_ECRYPTFS_MARKER);
827 ecryptfs_printk(KERN_DEBUG, "(m_1 ^ MAGIC_ECRYPTFS_MARKER) = "
828 "[0x%.8x]\n", (m_1 ^ MAGIC_ECRYPTFS_MARKER));
832 struct ecryptfs_flag_map_elem {
837 /* Add support for additional flags by adding elements here. */
838 static struct ecryptfs_flag_map_elem ecryptfs_flag_map[] = {
839 {0x00000001, ECRYPTFS_ENABLE_HMAC},
840 {0x00000002, ECRYPTFS_ENCRYPTED},
841 {0x00000004, ECRYPTFS_METADATA_IN_XATTR},
842 {0x00000008, ECRYPTFS_ENCRYPT_FILENAMES}
846 * ecryptfs_process_flags
847 * @crypt_stat: The cryptographic context
848 * @page_virt: Source data to be parsed
849 * @bytes_read: Updated with the number of bytes read
851 static void ecryptfs_process_flags(struct ecryptfs_crypt_stat *crypt_stat,
852 char *page_virt, int *bytes_read)
857 flags = get_unaligned_be32(page_virt);
858 for (i = 0; i < ARRAY_SIZE(ecryptfs_flag_map); i++)
859 if (flags & ecryptfs_flag_map[i].file_flag) {
860 crypt_stat->flags |= ecryptfs_flag_map[i].local_flag;
862 crypt_stat->flags &= ~(ecryptfs_flag_map[i].local_flag);
863 /* Version is in top 8 bits of the 32-bit flag vector */
864 crypt_stat->file_version = ((flags >> 24) & 0xFF);
869 * write_ecryptfs_marker
870 * @page_virt: The pointer to in a page to begin writing the marker
871 * @written: Number of bytes written
873 * Marker = 0x3c81b7f5
875 static void write_ecryptfs_marker(char *page_virt, size_t *written)
879 get_random_bytes(&m_1, (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2));
880 m_2 = (m_1 ^ MAGIC_ECRYPTFS_MARKER);
881 put_unaligned_be32(m_1, page_virt);
882 page_virt += (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2);
883 put_unaligned_be32(m_2, page_virt);
884 (*written) = MAGIC_ECRYPTFS_MARKER_SIZE_BYTES;
887 void ecryptfs_write_crypt_stat_flags(char *page_virt,
888 struct ecryptfs_crypt_stat *crypt_stat,
894 for (i = 0; i < ARRAY_SIZE(ecryptfs_flag_map); i++)
895 if (crypt_stat->flags & ecryptfs_flag_map[i].local_flag)
896 flags |= ecryptfs_flag_map[i].file_flag;
897 /* Version is in top 8 bits of the 32-bit flag vector */
898 flags |= ((((u8)crypt_stat->file_version) << 24) & 0xFF000000);
899 put_unaligned_be32(flags, page_virt);
903 struct ecryptfs_cipher_code_str_map_elem {
908 /* Add support for additional ciphers by adding elements here. The
909 * cipher_code is whatever OpenPGP applications use to identify the
910 * ciphers. List in order of probability. */
911 static struct ecryptfs_cipher_code_str_map_elem
912 ecryptfs_cipher_code_str_map[] = {
913 {"aes",RFC2440_CIPHER_AES_128 },
914 {"blowfish", RFC2440_CIPHER_BLOWFISH},
915 {"des3_ede", RFC2440_CIPHER_DES3_EDE},
916 {"cast5", RFC2440_CIPHER_CAST_5},
917 {"twofish", RFC2440_CIPHER_TWOFISH},
918 {"cast6", RFC2440_CIPHER_CAST_6},
919 {"aes", RFC2440_CIPHER_AES_192},
920 {"aes", RFC2440_CIPHER_AES_256}
924 * ecryptfs_code_for_cipher_string
925 * @cipher_name: The string alias for the cipher
926 * @key_bytes: Length of key in bytes; used for AES code selection
928 * Returns zero on no match, or the cipher code on match
930 u8 ecryptfs_code_for_cipher_string(char *cipher_name, size_t key_bytes)
934 struct ecryptfs_cipher_code_str_map_elem *map =
935 ecryptfs_cipher_code_str_map;
937 if (strcmp(cipher_name, "aes") == 0) {
940 code = RFC2440_CIPHER_AES_128;
943 code = RFC2440_CIPHER_AES_192;
946 code = RFC2440_CIPHER_AES_256;
949 for (i = 0; i < ARRAY_SIZE(ecryptfs_cipher_code_str_map); i++)
950 if (strcmp(cipher_name, map[i].cipher_str) == 0) {
951 code = map[i].cipher_code;
959 * ecryptfs_cipher_code_to_string
960 * @str: Destination to write out the cipher name
961 * @cipher_code: The code to convert to cipher name string
963 * Returns zero on success
965 int ecryptfs_cipher_code_to_string(char *str, u8 cipher_code)
971 for (i = 0; i < ARRAY_SIZE(ecryptfs_cipher_code_str_map); i++)
972 if (cipher_code == ecryptfs_cipher_code_str_map[i].cipher_code)
973 strcpy(str, ecryptfs_cipher_code_str_map[i].cipher_str);
974 if (str[0] == '\0') {
975 ecryptfs_printk(KERN_WARNING, "Cipher code not recognized: "
976 "[%d]\n", cipher_code);
982 int ecryptfs_read_and_validate_header_region(struct inode *inode)
984 u8 file_size[ECRYPTFS_SIZE_AND_MARKER_BYTES];
985 u8 *marker = file_size + ECRYPTFS_FILE_SIZE_BYTES;
988 rc = ecryptfs_read_lower(file_size, 0, ECRYPTFS_SIZE_AND_MARKER_BYTES,
992 else if (rc < ECRYPTFS_SIZE_AND_MARKER_BYTES)
994 rc = ecryptfs_validate_marker(marker);
996 ecryptfs_i_size_init(file_size, inode);
1001 ecryptfs_write_header_metadata(char *virt,
1002 struct ecryptfs_crypt_stat *crypt_stat,
1005 u32 header_extent_size;
1006 u16 num_header_extents_at_front;
1008 header_extent_size = (u32)crypt_stat->extent_size;
1009 num_header_extents_at_front =
1010 (u16)(crypt_stat->metadata_size / crypt_stat->extent_size);
1011 put_unaligned_be32(header_extent_size, virt);
1013 put_unaligned_be16(num_header_extents_at_front, virt);
1017 struct kmem_cache *ecryptfs_header_cache;
1020 * ecryptfs_write_headers_virt
1021 * @page_virt: The virtual address to write the headers to
1022 * @max: The size of memory allocated at page_virt
1023 * @size: Set to the number of bytes written by this function
1024 * @crypt_stat: The cryptographic context
1025 * @ecryptfs_dentry: The eCryptfs dentry
1030 * Octets 0-7: Unencrypted file size (big-endian)
1031 * Octets 8-15: eCryptfs special marker
1032 * Octets 16-19: Flags
1033 * Octet 16: File format version number (between 0 and 255)
1034 * Octets 17-18: Reserved
1035 * Octet 19: Bit 1 (lsb): Reserved
1037 * Bits 3-8: Reserved
1038 * Octets 20-23: Header extent size (big-endian)
1039 * Octets 24-25: Number of header extents at front of file
1041 * Octet 26: Begin RFC 2440 authentication token packet set
1043 * Lower data (CBC encrypted)
1045 * Lower data (CBC encrypted)
1048 * Returns zero on success
1050 static int ecryptfs_write_headers_virt(char *page_virt, size_t max,
1052 struct ecryptfs_crypt_stat *crypt_stat,
1053 struct dentry *ecryptfs_dentry)
1059 offset = ECRYPTFS_FILE_SIZE_BYTES;
1060 write_ecryptfs_marker((page_virt + offset), &written);
1062 ecryptfs_write_crypt_stat_flags((page_virt + offset), crypt_stat,
1065 ecryptfs_write_header_metadata((page_virt + offset), crypt_stat,
1068 rc = ecryptfs_generate_key_packet_set((page_virt + offset), crypt_stat,
1069 ecryptfs_dentry, &written,
1072 ecryptfs_printk(KERN_WARNING, "Error generating key packet "
1073 "set; rc = [%d]\n", rc);
1082 ecryptfs_write_metadata_to_contents(struct inode *ecryptfs_inode,
1083 char *virt, size_t virt_len)
1087 rc = ecryptfs_write_lower(ecryptfs_inode, virt,
1090 printk(KERN_ERR "%s: Error attempting to write header "
1091 "information to lower file; rc = [%d]\n", __func__, rc);
1098 ecryptfs_write_metadata_to_xattr(struct dentry *ecryptfs_dentry,
1099 struct inode *ecryptfs_inode,
1100 char *page_virt, size_t size)
1103 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
1104 struct inode *lower_inode = d_inode(lower_dentry);
1106 if (!(lower_inode->i_opflags & IOP_XATTR)) {
1111 inode_lock(lower_inode);
1112 rc = __vfs_setxattr(&init_user_ns, lower_dentry, lower_inode,
1113 ECRYPTFS_XATTR_NAME, page_virt, size, 0);
1114 if (!rc && ecryptfs_inode)
1115 fsstack_copy_attr_all(ecryptfs_inode, lower_inode);
1116 inode_unlock(lower_inode);
1121 static unsigned long ecryptfs_get_zeroed_pages(gfp_t gfp_mask,
1126 page = alloc_pages(gfp_mask | __GFP_ZERO, order);
1128 return (unsigned long) page_address(page);
1133 * ecryptfs_write_metadata
1134 * @ecryptfs_dentry: The eCryptfs dentry, which should be negative
1135 * @ecryptfs_inode: The newly created eCryptfs inode
1137 * Write the file headers out. This will likely involve a userspace
1138 * callout, in which the session key is encrypted with one or more
1139 * public keys and/or the passphrase necessary to do the encryption is
1140 * retrieved via a prompt. Exactly what happens at this point should
1141 * be policy-dependent.
1143 * Returns zero on success; non-zero on error
1145 int ecryptfs_write_metadata(struct dentry *ecryptfs_dentry,
1146 struct inode *ecryptfs_inode)
1148 struct ecryptfs_crypt_stat *crypt_stat =
1149 &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
1156 if (likely(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
1157 if (!(crypt_stat->flags & ECRYPTFS_KEY_VALID)) {
1158 printk(KERN_ERR "Key is invalid; bailing out\n");
1163 printk(KERN_WARNING "%s: Encrypted flag not set\n",
1168 virt_len = crypt_stat->metadata_size;
1169 order = get_order(virt_len);
1170 /* Released in this function */
1171 virt = (char *)ecryptfs_get_zeroed_pages(GFP_KERNEL, order);
1173 printk(KERN_ERR "%s: Out of memory\n", __func__);
1177 /* Zeroed page ensures the in-header unencrypted i_size is set to 0 */
1178 rc = ecryptfs_write_headers_virt(virt, virt_len, &size, crypt_stat,
1181 printk(KERN_ERR "%s: Error whilst writing headers; rc = [%d]\n",
1185 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
1186 rc = ecryptfs_write_metadata_to_xattr(ecryptfs_dentry, ecryptfs_inode,
1189 rc = ecryptfs_write_metadata_to_contents(ecryptfs_inode, virt,
1192 printk(KERN_ERR "%s: Error writing metadata out to lower file; "
1193 "rc = [%d]\n", __func__, rc);
1197 free_pages((unsigned long)virt, order);
1202 #define ECRYPTFS_DONT_VALIDATE_HEADER_SIZE 0
1203 #define ECRYPTFS_VALIDATE_HEADER_SIZE 1
1204 static int parse_header_metadata(struct ecryptfs_crypt_stat *crypt_stat,
1205 char *virt, int *bytes_read,
1206 int validate_header_size)
1209 u32 header_extent_size;
1210 u16 num_header_extents_at_front;
1212 header_extent_size = get_unaligned_be32(virt);
1213 virt += sizeof(__be32);
1214 num_header_extents_at_front = get_unaligned_be16(virt);
1215 crypt_stat->metadata_size = (((size_t)num_header_extents_at_front
1216 * (size_t)header_extent_size));
1217 (*bytes_read) = (sizeof(__be32) + sizeof(__be16));
1218 if ((validate_header_size == ECRYPTFS_VALIDATE_HEADER_SIZE)
1219 && (crypt_stat->metadata_size
1220 < ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE)) {
1222 printk(KERN_WARNING "Invalid header size: [%zd]\n",
1223 crypt_stat->metadata_size);
1229 * set_default_header_data
1230 * @crypt_stat: The cryptographic context
1232 * For version 0 file format; this function is only for backwards
1233 * compatibility for files created with the prior versions of
1236 static void set_default_header_data(struct ecryptfs_crypt_stat *crypt_stat)
1238 crypt_stat->metadata_size = ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
1241 void ecryptfs_i_size_init(const char *page_virt, struct inode *inode)
1243 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
1244 struct ecryptfs_crypt_stat *crypt_stat;
1247 crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
1249 &ecryptfs_superblock_to_private(inode->i_sb)->mount_crypt_stat;
1250 if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED) {
1251 file_size = i_size_read(ecryptfs_inode_to_lower(inode));
1252 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
1253 file_size += crypt_stat->metadata_size;
1255 file_size = get_unaligned_be64(page_virt);
1256 i_size_write(inode, (loff_t)file_size);
1257 crypt_stat->flags |= ECRYPTFS_I_SIZE_INITIALIZED;
1261 * ecryptfs_read_headers_virt
1262 * @page_virt: The virtual address into which to read the headers
1263 * @crypt_stat: The cryptographic context
1264 * @ecryptfs_dentry: The eCryptfs dentry
1265 * @validate_header_size: Whether to validate the header size while reading
1267 * Read/parse the header data. The header format is detailed in the
1268 * comment block for the ecryptfs_write_headers_virt() function.
1270 * Returns zero on success
1272 static int ecryptfs_read_headers_virt(char *page_virt,
1273 struct ecryptfs_crypt_stat *crypt_stat,
1274 struct dentry *ecryptfs_dentry,
1275 int validate_header_size)
1281 ecryptfs_set_default_sizes(crypt_stat);
1282 crypt_stat->mount_crypt_stat = &ecryptfs_superblock_to_private(
1283 ecryptfs_dentry->d_sb)->mount_crypt_stat;
1284 offset = ECRYPTFS_FILE_SIZE_BYTES;
1285 rc = ecryptfs_validate_marker(page_virt + offset);
1288 if (!(crypt_stat->flags & ECRYPTFS_I_SIZE_INITIALIZED))
1289 ecryptfs_i_size_init(page_virt, d_inode(ecryptfs_dentry));
1290 offset += MAGIC_ECRYPTFS_MARKER_SIZE_BYTES;
1291 ecryptfs_process_flags(crypt_stat, (page_virt + offset), &bytes_read);
1292 if (crypt_stat->file_version > ECRYPTFS_SUPPORTED_FILE_VERSION) {
1293 ecryptfs_printk(KERN_WARNING, "File version is [%d]; only "
1294 "file version [%d] is supported by this "
1295 "version of eCryptfs\n",
1296 crypt_stat->file_version,
1297 ECRYPTFS_SUPPORTED_FILE_VERSION);
1301 offset += bytes_read;
1302 if (crypt_stat->file_version >= 1) {
1303 rc = parse_header_metadata(crypt_stat, (page_virt + offset),
1304 &bytes_read, validate_header_size);
1306 ecryptfs_printk(KERN_WARNING, "Error reading header "
1307 "metadata; rc = [%d]\n", rc);
1309 offset += bytes_read;
1311 set_default_header_data(crypt_stat);
1312 rc = ecryptfs_parse_packet_set(crypt_stat, (page_virt + offset),
1319 * ecryptfs_read_xattr_region
1320 * @page_virt: The vitual address into which to read the xattr data
1321 * @ecryptfs_inode: The eCryptfs inode
1323 * Attempts to read the crypto metadata from the extended attribute
1324 * region of the lower file.
1326 * Returns zero on success; non-zero on error
1328 int ecryptfs_read_xattr_region(char *page_virt, struct inode *ecryptfs_inode)
1330 struct dentry *lower_dentry =
1331 ecryptfs_inode_to_private(ecryptfs_inode)->lower_file->f_path.dentry;
1335 size = ecryptfs_getxattr_lower(lower_dentry,
1336 ecryptfs_inode_to_lower(ecryptfs_inode),
1337 ECRYPTFS_XATTR_NAME,
1338 page_virt, ECRYPTFS_DEFAULT_EXTENT_SIZE);
1340 if (unlikely(ecryptfs_verbosity > 0))
1341 printk(KERN_INFO "Error attempting to read the [%s] "
1342 "xattr from the lower file; return value = "
1343 "[%zd]\n", ECRYPTFS_XATTR_NAME, size);
1351 int ecryptfs_read_and_validate_xattr_region(struct dentry *dentry,
1352 struct inode *inode)
1354 u8 file_size[ECRYPTFS_SIZE_AND_MARKER_BYTES];
1355 u8 *marker = file_size + ECRYPTFS_FILE_SIZE_BYTES;
1358 rc = ecryptfs_getxattr_lower(ecryptfs_dentry_to_lower(dentry),
1359 ecryptfs_inode_to_lower(inode),
1360 ECRYPTFS_XATTR_NAME, file_size,
1361 ECRYPTFS_SIZE_AND_MARKER_BYTES);
1364 else if (rc < ECRYPTFS_SIZE_AND_MARKER_BYTES)
1366 rc = ecryptfs_validate_marker(marker);
1368 ecryptfs_i_size_init(file_size, inode);
1373 * ecryptfs_read_metadata
1375 * Common entry point for reading file metadata. From here, we could
1376 * retrieve the header information from the header region of the file,
1377 * the xattr region of the file, or some other repository that is
1378 * stored separately from the file itself. The current implementation
1379 * supports retrieving the metadata information from the file contents
1380 * and from the xattr region.
1382 * Returns zero if valid headers found and parsed; non-zero otherwise
1384 int ecryptfs_read_metadata(struct dentry *ecryptfs_dentry)
1388 struct inode *ecryptfs_inode = d_inode(ecryptfs_dentry);
1389 struct ecryptfs_crypt_stat *crypt_stat =
1390 &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
1391 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
1392 &ecryptfs_superblock_to_private(
1393 ecryptfs_dentry->d_sb)->mount_crypt_stat;
1395 ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
1397 /* Read the first page from the underlying file */
1398 page_virt = kmem_cache_alloc(ecryptfs_header_cache, GFP_USER);
1403 rc = ecryptfs_read_lower(page_virt, 0, crypt_stat->extent_size,
1406 rc = ecryptfs_read_headers_virt(page_virt, crypt_stat,
1408 ECRYPTFS_VALIDATE_HEADER_SIZE);
1410 /* metadata is not in the file header, so try xattrs */
1411 memset(page_virt, 0, PAGE_SIZE);
1412 rc = ecryptfs_read_xattr_region(page_virt, ecryptfs_inode);
1414 printk(KERN_DEBUG "Valid eCryptfs headers not found in "
1415 "file header region or xattr region, inode %lu\n",
1416 ecryptfs_inode->i_ino);
1420 rc = ecryptfs_read_headers_virt(page_virt, crypt_stat,
1422 ECRYPTFS_DONT_VALIDATE_HEADER_SIZE);
1424 printk(KERN_DEBUG "Valid eCryptfs headers not found in "
1425 "file xattr region either, inode %lu\n",
1426 ecryptfs_inode->i_ino);
1429 if (crypt_stat->mount_crypt_stat->flags
1430 & ECRYPTFS_XATTR_METADATA_ENABLED) {
1431 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
1433 printk(KERN_WARNING "Attempt to access file with "
1434 "crypto metadata only in the extended attribute "
1435 "region, but eCryptfs was mounted without "
1436 "xattr support enabled. eCryptfs will not treat "
1437 "this like an encrypted file, inode %lu\n",
1438 ecryptfs_inode->i_ino);
1444 memset(page_virt, 0, PAGE_SIZE);
1445 kmem_cache_free(ecryptfs_header_cache, page_virt);
1451 * ecryptfs_encrypt_filename - encrypt filename
1453 * CBC-encrypts the filename. We do not want to encrypt the same
1454 * filename with the same key and IV, which may happen with hard
1455 * links, so we prepend random bits to each filename.
1457 * Returns zero on success; non-zero otherwise
1460 ecryptfs_encrypt_filename(struct ecryptfs_filename *filename,
1461 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
1465 filename->encrypted_filename = NULL;
1466 filename->encrypted_filename_size = 0;
1467 if (mount_crypt_stat && (mount_crypt_stat->flags
1468 & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK)) {
1470 size_t remaining_bytes;
1472 rc = ecryptfs_write_tag_70_packet(
1474 &filename->encrypted_filename_size,
1475 mount_crypt_stat, NULL,
1476 filename->filename_size);
1478 printk(KERN_ERR "%s: Error attempting to get packet "
1479 "size for tag 72; rc = [%d]\n", __func__,
1481 filename->encrypted_filename_size = 0;
1484 filename->encrypted_filename =
1485 kmalloc(filename->encrypted_filename_size, GFP_KERNEL);
1486 if (!filename->encrypted_filename) {
1490 remaining_bytes = filename->encrypted_filename_size;
1491 rc = ecryptfs_write_tag_70_packet(filename->encrypted_filename,
1496 filename->filename_size);
1498 printk(KERN_ERR "%s: Error attempting to generate "
1499 "tag 70 packet; rc = [%d]\n", __func__,
1501 kfree(filename->encrypted_filename);
1502 filename->encrypted_filename = NULL;
1503 filename->encrypted_filename_size = 0;
1506 filename->encrypted_filename_size = packet_size;
1508 printk(KERN_ERR "%s: No support for requested filename "
1509 "encryption method in this release\n", __func__);
1517 static int ecryptfs_copy_filename(char **copied_name, size_t *copied_name_size,
1518 const char *name, size_t name_size)
1522 (*copied_name) = kmalloc((name_size + 1), GFP_KERNEL);
1523 if (!(*copied_name)) {
1527 memcpy((void *)(*copied_name), (void *)name, name_size);
1528 (*copied_name)[(name_size)] = '\0'; /* Only for convenience
1529 * in printing out the
1532 (*copied_name_size) = name_size;
1538 * ecryptfs_process_key_cipher - Perform key cipher initialization.
1539 * @key_tfm: Crypto context for key material, set by this function
1540 * @cipher_name: Name of the cipher
1541 * @key_size: Size of the key in bytes
1543 * Returns zero on success. Any crypto_tfm structs allocated here
1544 * should be released by other functions, such as on a superblock put
1545 * event, regardless of whether this function succeeds for fails.
1548 ecryptfs_process_key_cipher(struct crypto_skcipher **key_tfm,
1549 char *cipher_name, size_t *key_size)
1551 char dummy_key[ECRYPTFS_MAX_KEY_BYTES];
1552 char *full_alg_name = NULL;
1556 if (*key_size > ECRYPTFS_MAX_KEY_BYTES) {
1558 printk(KERN_ERR "Requested key size is [%zd] bytes; maximum "
1559 "allowable is [%d]\n", *key_size, ECRYPTFS_MAX_KEY_BYTES);
1562 rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name, cipher_name,
1566 *key_tfm = crypto_alloc_skcipher(full_alg_name, 0, CRYPTO_ALG_ASYNC);
1567 if (IS_ERR(*key_tfm)) {
1568 rc = PTR_ERR(*key_tfm);
1569 printk(KERN_ERR "Unable to allocate crypto cipher with name "
1570 "[%s]; rc = [%d]\n", full_alg_name, rc);
1573 crypto_skcipher_set_flags(*key_tfm, CRYPTO_TFM_REQ_FORBID_WEAK_KEYS);
1575 *key_size = crypto_skcipher_max_keysize(*key_tfm);
1576 get_random_bytes(dummy_key, *key_size);
1577 rc = crypto_skcipher_setkey(*key_tfm, dummy_key, *key_size);
1579 printk(KERN_ERR "Error attempting to set key of size [%zd] for "
1580 "cipher [%s]; rc = [%d]\n", *key_size, full_alg_name,
1586 kfree(full_alg_name);
1590 struct kmem_cache *ecryptfs_key_tfm_cache;
1591 static struct list_head key_tfm_list;
1592 DEFINE_MUTEX(key_tfm_list_mutex);
1594 int __init ecryptfs_init_crypto(void)
1596 INIT_LIST_HEAD(&key_tfm_list);
1601 * ecryptfs_destroy_crypto - free all cached key_tfms on key_tfm_list
1603 * Called only at module unload time
1605 int ecryptfs_destroy_crypto(void)
1607 struct ecryptfs_key_tfm *key_tfm, *key_tfm_tmp;
1609 mutex_lock(&key_tfm_list_mutex);
1610 list_for_each_entry_safe(key_tfm, key_tfm_tmp, &key_tfm_list,
1612 list_del(&key_tfm->key_tfm_list);
1613 crypto_free_skcipher(key_tfm->key_tfm);
1614 kmem_cache_free(ecryptfs_key_tfm_cache, key_tfm);
1616 mutex_unlock(&key_tfm_list_mutex);
1621 ecryptfs_add_new_key_tfm(struct ecryptfs_key_tfm **key_tfm, char *cipher_name,
1624 struct ecryptfs_key_tfm *tmp_tfm;
1627 BUG_ON(!mutex_is_locked(&key_tfm_list_mutex));
1629 tmp_tfm = kmem_cache_alloc(ecryptfs_key_tfm_cache, GFP_KERNEL);
1631 (*key_tfm) = tmp_tfm;
1636 mutex_init(&tmp_tfm->key_tfm_mutex);
1637 strncpy(tmp_tfm->cipher_name, cipher_name,
1638 ECRYPTFS_MAX_CIPHER_NAME_SIZE);
1639 tmp_tfm->cipher_name[ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
1640 tmp_tfm->key_size = key_size;
1641 rc = ecryptfs_process_key_cipher(&tmp_tfm->key_tfm,
1642 tmp_tfm->cipher_name,
1643 &tmp_tfm->key_size);
1645 printk(KERN_ERR "Error attempting to initialize key TFM "
1646 "cipher with name = [%s]; rc = [%d]\n",
1647 tmp_tfm->cipher_name, rc);
1648 kmem_cache_free(ecryptfs_key_tfm_cache, tmp_tfm);
1653 list_add(&tmp_tfm->key_tfm_list, &key_tfm_list);
1659 * ecryptfs_tfm_exists - Search for existing tfm for cipher_name.
1660 * @cipher_name: the name of the cipher to search for
1661 * @key_tfm: set to corresponding tfm if found
1663 * Searches for cached key_tfm matching @cipher_name
1664 * Must be called with &key_tfm_list_mutex held
1665 * Returns 1 if found, with @key_tfm set
1666 * Returns 0 if not found, with @key_tfm set to NULL
1668 int ecryptfs_tfm_exists(char *cipher_name, struct ecryptfs_key_tfm **key_tfm)
1670 struct ecryptfs_key_tfm *tmp_key_tfm;
1672 BUG_ON(!mutex_is_locked(&key_tfm_list_mutex));
1674 list_for_each_entry(tmp_key_tfm, &key_tfm_list, key_tfm_list) {
1675 if (strcmp(tmp_key_tfm->cipher_name, cipher_name) == 0) {
1677 (*key_tfm) = tmp_key_tfm;
1687 * ecryptfs_get_tfm_and_mutex_for_cipher_name
1689 * @tfm: set to cached tfm found, or new tfm created
1690 * @tfm_mutex: set to mutex for cached tfm found, or new tfm created
1691 * @cipher_name: the name of the cipher to search for and/or add
1693 * Sets pointers to @tfm & @tfm_mutex matching @cipher_name.
1694 * Searches for cached item first, and creates new if not found.
1695 * Returns 0 on success, non-zero if adding new cipher failed
1697 int ecryptfs_get_tfm_and_mutex_for_cipher_name(struct crypto_skcipher **tfm,
1698 struct mutex **tfm_mutex,
1701 struct ecryptfs_key_tfm *key_tfm;
1705 (*tfm_mutex) = NULL;
1707 mutex_lock(&key_tfm_list_mutex);
1708 if (!ecryptfs_tfm_exists(cipher_name, &key_tfm)) {
1709 rc = ecryptfs_add_new_key_tfm(&key_tfm, cipher_name, 0);
1711 printk(KERN_ERR "Error adding new key_tfm to list; "
1716 (*tfm) = key_tfm->key_tfm;
1717 (*tfm_mutex) = &key_tfm->key_tfm_mutex;
1719 mutex_unlock(&key_tfm_list_mutex);
1723 /* 64 characters forming a 6-bit target field */
1724 static unsigned char *portable_filename_chars = ("-.0123456789ABCD"
1727 "klmnopqrstuvwxyz");
1729 /* We could either offset on every reverse map or just pad some 0x00's
1730 * at the front here */
1731 static const unsigned char filename_rev_map[256] = {
1732 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 7 */
1733 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 15 */
1734 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 23 */
1735 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 31 */
1736 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 39 */
1737 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, /* 47 */
1738 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, /* 55 */
1739 0x0A, 0x0B, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 63 */
1740 0x00, 0x0C, 0x0D, 0x0E, 0x0F, 0x10, 0x11, 0x12, /* 71 */
1741 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1A, /* 79 */
1742 0x1B, 0x1C, 0x1D, 0x1E, 0x1F, 0x20, 0x21, 0x22, /* 87 */
1743 0x23, 0x24, 0x25, 0x00, 0x00, 0x00, 0x00, 0x00, /* 95 */
1744 0x00, 0x26, 0x27, 0x28, 0x29, 0x2A, 0x2B, 0x2C, /* 103 */
1745 0x2D, 0x2E, 0x2F, 0x30, 0x31, 0x32, 0x33, 0x34, /* 111 */
1746 0x35, 0x36, 0x37, 0x38, 0x39, 0x3A, 0x3B, 0x3C, /* 119 */
1747 0x3D, 0x3E, 0x3F /* 123 - 255 initialized to 0x00 */
1751 * ecryptfs_encode_for_filename
1752 * @dst: Destination location for encoded filename
1753 * @dst_size: Size of the encoded filename in bytes
1754 * @src: Source location for the filename to encode
1755 * @src_size: Size of the source in bytes
1757 static void ecryptfs_encode_for_filename(unsigned char *dst, size_t *dst_size,
1758 unsigned char *src, size_t src_size)
1761 size_t block_num = 0;
1762 size_t dst_offset = 0;
1763 unsigned char last_block[3];
1765 if (src_size == 0) {
1769 num_blocks = (src_size / 3);
1770 if ((src_size % 3) == 0) {
1771 memcpy(last_block, (&src[src_size - 3]), 3);
1774 last_block[2] = 0x00;
1775 switch (src_size % 3) {
1777 last_block[0] = src[src_size - 1];
1778 last_block[1] = 0x00;
1781 last_block[0] = src[src_size - 2];
1782 last_block[1] = src[src_size - 1];
1785 (*dst_size) = (num_blocks * 4);
1788 while (block_num < num_blocks) {
1789 unsigned char *src_block;
1790 unsigned char dst_block[4];
1792 if (block_num == (num_blocks - 1))
1793 src_block = last_block;
1795 src_block = &src[block_num * 3];
1796 dst_block[0] = ((src_block[0] >> 2) & 0x3F);
1797 dst_block[1] = (((src_block[0] << 4) & 0x30)
1798 | ((src_block[1] >> 4) & 0x0F));
1799 dst_block[2] = (((src_block[1] << 2) & 0x3C)
1800 | ((src_block[2] >> 6) & 0x03));
1801 dst_block[3] = (src_block[2] & 0x3F);
1802 dst[dst_offset++] = portable_filename_chars[dst_block[0]];
1803 dst[dst_offset++] = portable_filename_chars[dst_block[1]];
1804 dst[dst_offset++] = portable_filename_chars[dst_block[2]];
1805 dst[dst_offset++] = portable_filename_chars[dst_block[3]];
1812 static size_t ecryptfs_max_decoded_size(size_t encoded_size)
1814 /* Not exact; conservatively long. Every block of 4
1815 * encoded characters decodes into a block of 3
1816 * decoded characters. This segment of code provides
1817 * the caller with the maximum amount of allocated
1818 * space that @dst will need to point to in a
1819 * subsequent call. */
1820 return ((encoded_size + 1) * 3) / 4;
1824 * ecryptfs_decode_from_filename
1825 * @dst: If NULL, this function only sets @dst_size and returns. If
1826 * non-NULL, this function decodes the encoded octets in @src
1827 * into the memory that @dst points to.
1828 * @dst_size: Set to the size of the decoded string.
1829 * @src: The encoded set of octets to decode.
1830 * @src_size: The size of the encoded set of octets to decode.
1833 ecryptfs_decode_from_filename(unsigned char *dst, size_t *dst_size,
1834 const unsigned char *src, size_t src_size)
1836 u8 current_bit_offset = 0;
1837 size_t src_byte_offset = 0;
1838 size_t dst_byte_offset = 0;
1841 (*dst_size) = ecryptfs_max_decoded_size(src_size);
1844 while (src_byte_offset < src_size) {
1845 unsigned char src_byte =
1846 filename_rev_map[(int)src[src_byte_offset]];
1848 switch (current_bit_offset) {
1850 dst[dst_byte_offset] = (src_byte << 2);
1851 current_bit_offset = 6;
1854 dst[dst_byte_offset++] |= (src_byte >> 4);
1855 dst[dst_byte_offset] = ((src_byte & 0xF)
1857 current_bit_offset = 4;
1860 dst[dst_byte_offset++] |= (src_byte >> 2);
1861 dst[dst_byte_offset] = (src_byte << 6);
1862 current_bit_offset = 2;
1865 dst[dst_byte_offset++] |= (src_byte);
1866 current_bit_offset = 0;
1871 (*dst_size) = dst_byte_offset;
1877 * ecryptfs_encrypt_and_encode_filename - converts a plaintext file name to cipher text
1878 * @encoded_name: The encrypted name
1879 * @encoded_name_size: Length of the encrypted name
1880 * @mount_crypt_stat: The crypt_stat struct associated with the file name to encode
1881 * @name: The plaintext name
1882 * @name_size: The length of the plaintext name
1884 * Encrypts and encodes a filename into something that constitutes a
1885 * valid filename for a filesystem, with printable characters.
1887 * We assume that we have a properly initialized crypto context,
1888 * pointed to by crypt_stat->tfm.
1890 * Returns zero on success; non-zero on otherwise
1892 int ecryptfs_encrypt_and_encode_filename(
1893 char **encoded_name,
1894 size_t *encoded_name_size,
1895 struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
1896 const char *name, size_t name_size)
1898 size_t encoded_name_no_prefix_size;
1901 (*encoded_name) = NULL;
1902 (*encoded_name_size) = 0;
1903 if (mount_crypt_stat && (mount_crypt_stat->flags
1904 & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)) {
1905 struct ecryptfs_filename *filename;
1907 filename = kzalloc(sizeof(*filename), GFP_KERNEL);
1912 filename->filename = (char *)name;
1913 filename->filename_size = name_size;
1914 rc = ecryptfs_encrypt_filename(filename, mount_crypt_stat);
1916 printk(KERN_ERR "%s: Error attempting to encrypt "
1917 "filename; rc = [%d]\n", __func__, rc);
1921 ecryptfs_encode_for_filename(
1922 NULL, &encoded_name_no_prefix_size,
1923 filename->encrypted_filename,
1924 filename->encrypted_filename_size);
1925 if (mount_crypt_stat
1926 && (mount_crypt_stat->flags
1927 & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK))
1928 (*encoded_name_size) =
1929 (ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE
1930 + encoded_name_no_prefix_size);
1932 (*encoded_name_size) =
1933 (ECRYPTFS_FEK_ENCRYPTED_FILENAME_PREFIX_SIZE
1934 + encoded_name_no_prefix_size);
1935 (*encoded_name) = kmalloc((*encoded_name_size) + 1, GFP_KERNEL);
1936 if (!(*encoded_name)) {
1938 kfree(filename->encrypted_filename);
1942 if (mount_crypt_stat
1943 && (mount_crypt_stat->flags
1944 & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK)) {
1945 memcpy((*encoded_name),
1946 ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX,
1947 ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE);
1948 ecryptfs_encode_for_filename(
1950 + ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE),
1951 &encoded_name_no_prefix_size,
1952 filename->encrypted_filename,
1953 filename->encrypted_filename_size);
1954 (*encoded_name_size) =
1955 (ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE
1956 + encoded_name_no_prefix_size);
1957 (*encoded_name)[(*encoded_name_size)] = '\0';
1962 printk(KERN_ERR "%s: Error attempting to encode "
1963 "encrypted filename; rc = [%d]\n", __func__,
1965 kfree((*encoded_name));
1966 (*encoded_name) = NULL;
1967 (*encoded_name_size) = 0;
1969 kfree(filename->encrypted_filename);
1972 rc = ecryptfs_copy_filename(encoded_name,
1980 static bool is_dot_dotdot(const char *name, size_t name_size)
1982 if (name_size == 1 && name[0] == '.')
1984 else if (name_size == 2 && name[0] == '.' && name[1] == '.')
1991 * ecryptfs_decode_and_decrypt_filename - converts the encoded cipher text name to decoded plaintext
1992 * @plaintext_name: The plaintext name
1993 * @plaintext_name_size: The plaintext name size
1994 * @sb: Ecryptfs's super_block
1995 * @name: The filename in cipher text
1996 * @name_size: The cipher text name size
1998 * Decrypts and decodes the filename.
2000 * Returns zero on error; non-zero otherwise
2002 int ecryptfs_decode_and_decrypt_filename(char **plaintext_name,
2003 size_t *plaintext_name_size,
2004 struct super_block *sb,
2005 const char *name, size_t name_size)
2007 struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
2008 &ecryptfs_superblock_to_private(sb)->mount_crypt_stat;
2010 size_t decoded_name_size;
2014 if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) &&
2015 !(mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)) {
2016 if (is_dot_dotdot(name, name_size)) {
2017 rc = ecryptfs_copy_filename(plaintext_name,
2018 plaintext_name_size,
2023 if (name_size <= ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE ||
2024 strncmp(name, ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX,
2025 ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE)) {
2030 name += ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE;
2031 name_size -= ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE;
2032 ecryptfs_decode_from_filename(NULL, &decoded_name_size,
2034 decoded_name = kmalloc(decoded_name_size, GFP_KERNEL);
2035 if (!decoded_name) {
2039 ecryptfs_decode_from_filename(decoded_name, &decoded_name_size,
2041 rc = ecryptfs_parse_tag_70_packet(plaintext_name,
2042 plaintext_name_size,
2048 ecryptfs_printk(KERN_DEBUG,
2049 "%s: Could not parse tag 70 packet from filename\n",
2054 rc = ecryptfs_copy_filename(plaintext_name,
2055 plaintext_name_size,
2060 kfree(decoded_name);
2065 #define ENC_NAME_MAX_BLOCKLEN_8_OR_16 143
2067 int ecryptfs_set_f_namelen(long *namelen, long lower_namelen,
2068 struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
2070 struct crypto_skcipher *tfm;
2071 struct mutex *tfm_mutex;
2072 size_t cipher_blocksize;
2075 if (!(mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)) {
2076 (*namelen) = lower_namelen;
2080 rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&tfm, &tfm_mutex,
2081 mount_crypt_stat->global_default_fn_cipher_name);
2087 mutex_lock(tfm_mutex);
2088 cipher_blocksize = crypto_skcipher_blocksize(tfm);
2089 mutex_unlock(tfm_mutex);
2091 /* Return an exact amount for the common cases */
2092 if (lower_namelen == NAME_MAX
2093 && (cipher_blocksize == 8 || cipher_blocksize == 16)) {
2094 (*namelen) = ENC_NAME_MAX_BLOCKLEN_8_OR_16;
2098 /* Return a safe estimate for the uncommon cases */
2099 (*namelen) = lower_namelen;
2100 (*namelen) -= ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE;
2101 /* Since this is the max decoded size, subtract 1 "decoded block" len */
2102 (*namelen) = ecryptfs_max_decoded_size(*namelen) - 3;
2103 (*namelen) -= ECRYPTFS_TAG_70_MAX_METADATA_SIZE;
2104 (*namelen) -= ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES;
2105 /* Worst case is that the filename is padded nearly a full block size */
2106 (*namelen) -= cipher_blocksize - 1;