1	// SPDX-License-Identifier: GPL-2.0-or-later
2	/*
3	* eCryptfs: Linux filesystem encryption layer
4	*
5	* Copyright (C) 1997-2004 Erez Zadok
6	* Copyright (C) 2001-2004 Stony Brook University
7	* Copyright (C) 2004-2007 International Business Machines Corp.
8	* Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
9	* Michael C. Thompson <mcthomps@us.ibm.com>
10	*/
11
12	#include <crypto/hash.h>
13	#include <crypto/skcipher.h>
14	#include <linux/fs.h>
15	#include <linux/mount.h>
16	#include <linux/pagemap.h>
17	#include <linux/random.h>
18	#include <linux/compiler.h>
19	#include <linux/key.h>
20	#include <linux/namei.h>
21	#include <linux/file.h>
22	#include <linux/scatterlist.h>
23	#include <linux/slab.h>
24	#include <linux/unaligned.h>
25	#include <linux/kernel.h>
26	#include <linux/xattr.h>
27	#include "ecryptfs_kernel.h"
28
29	#define DECRYPT 0
30	#define ENCRYPT 1
31
32	/**
33	* ecryptfs_from_hex
34	* @dst: Buffer to take the bytes from src hex; must be at least of
35	* size (src_size / 2)
36	* @src: Buffer to be converted from a hex string representation to raw value
37	* @dst_size: size of dst buffer, or number of hex characters pairs to convert
38	*/
39	void ecryptfs_from_hex(char *dst, char *src, int dst_size)
40	{
41	int x;
42	char tmp[3] = { 0, };
43
44	for (x = 0; x < dst_size; x++) {
45	tmp[0] = src[x * 2];
46	tmp[1] = src[x * 2 + 1];
47	dst[x] = (unsigned char)simple_strtol(tmp, NULL, 16);
48	}
49	}
50
51	/**
52	* ecryptfs_calculate_md5 - calculates the md5 of @src
53	* @dst: Pointer to 16 bytes of allocated memory
54	* @crypt_stat: Pointer to crypt_stat struct for the current inode
55	* @src: Data to be md5'd
56	* @len: Length of @src
57	*
58	* Uses the allocated crypto context that crypt_stat references to
59	* generate the MD5 sum of the contents of src.
60	*/
61	static int ecryptfs_calculate_md5(char *dst,
62	struct ecryptfs_crypt_stat *crypt_stat,
63	char *src, int len)
64	{
65	int rc = crypto_shash_tfm_digest(tfm: crypt_stat->hash_tfm, data: src, len, out: dst);
66
67	if (rc) {
68	printk(KERN_ERR
69	"%s: Error computing crypto hash; rc = [%d]\n",
70	__func__, rc);
71	goto out;
72	}
73	out:
74	return rc;
75	}
76
77	static int ecryptfs_crypto_api_algify_cipher_name(char **algified_name,
78	char *cipher_name,
79	char *chaining_modifier)
80	{
81	int cipher_name_len = strlen(cipher_name);
82	int chaining_modifier_len = strlen(chaining_modifier);
83	int algified_name_len;
84	int rc;
85
86	algified_name_len = (chaining_modifier_len + cipher_name_len + 3);
87	(*algified_name) = kmalloc(algified_name_len, GFP_KERNEL);
88	if (!(*algified_name)) {
89	rc = -ENOMEM;
90	goto out;
91	}
92	snprintf(buf: (*algified_name), size: algified_name_len, fmt: "%s(%s)",
93	chaining_modifier, cipher_name);
94	rc = 0;
95	out:
96	return rc;
97	}
98
99	/**
100	* ecryptfs_derive_iv
101	* @iv: destination for the derived iv vale
102	* @crypt_stat: Pointer to crypt_stat struct for the current inode
103	* @offset: Offset of the extent whose IV we are to derive
104	*
105	* Generate the initialization vector from the given root IV and page
106	* offset.
107	*
108	* Returns zero on success; non-zero on error.
109	*/
110	int ecryptfs_derive_iv(char *iv, struct ecryptfs_crypt_stat *crypt_stat,
111	loff_t offset)
112	{
113	int rc = 0;
114	char dst[MD5_DIGEST_SIZE];
115	char src[ECRYPTFS_MAX_IV_BYTES + 16];
116
117	if (unlikely(ecryptfs_verbosity > 0)) {
118	ecryptfs_printk(KERN_DEBUG, "root iv:\n");
119	ecryptfs_dump_hex(data: crypt_stat->root_iv, bytes: crypt_stat->iv_bytes);
120	}
121	/* TODO: It is probably secure to just cast the least
122	* significant bits of the root IV into an unsigned long and
123	* add the offset to that rather than go through all this
124	* hashing business. -Halcrow */
125	memcpy(src, crypt_stat->root_iv, crypt_stat->iv_bytes);
126	memset((src + crypt_stat->iv_bytes), 0, 16);
127	snprintf(buf: (src + crypt_stat->iv_bytes), size: 16, fmt: "%lld", offset);
128	if (unlikely(ecryptfs_verbosity > 0)) {
129	ecryptfs_printk(KERN_DEBUG, "source:\n");
130	ecryptfs_dump_hex(data: src, bytes: (crypt_stat->iv_bytes + 16));
131	}
132	rc = ecryptfs_calculate_md5(dst, crypt_stat, src,
133	len: (crypt_stat->iv_bytes + 16));
134	if (rc) {
135	ecryptfs_printk(KERN_WARNING, "Error attempting to compute "
136	"MD5 while generating IV for a page\n");
137	goto out;
138	}
139	memcpy(iv, dst, crypt_stat->iv_bytes);
140	if (unlikely(ecryptfs_verbosity > 0)) {
141	ecryptfs_printk(KERN_DEBUG, "derived iv:\n");
142	ecryptfs_dump_hex(data: iv, bytes: crypt_stat->iv_bytes);
143	}
144	out:
145	return rc;
146	}
147
148	/**
149	* ecryptfs_init_crypt_stat
150	* @crypt_stat: Pointer to the crypt_stat struct to initialize.
151	*
152	* Initialize the crypt_stat structure.
153	*/
154	int ecryptfs_init_crypt_stat(struct ecryptfs_crypt_stat *crypt_stat)
155	{
156	struct crypto_shash *tfm;
157	int rc;
158
159	tfm = crypto_alloc_shash(ECRYPTFS_DEFAULT_HASH, type: 0, mask: 0);
160	if (IS_ERR(ptr: tfm)) {
161	rc = PTR_ERR(ptr: tfm);
162	ecryptfs_printk(KERN_ERR, "Error attempting to "
163	"allocate crypto context; rc = [%d]\n",
164	rc);
165	return rc;
166	}
167
168	memset((void *)crypt_stat, 0, sizeof(struct ecryptfs_crypt_stat));
169	INIT_LIST_HEAD(list: &crypt_stat->keysig_list);
170	mutex_init(&crypt_stat->keysig_list_mutex);
171	mutex_init(&crypt_stat->cs_mutex);
172	mutex_init(&crypt_stat->cs_tfm_mutex);
173	crypt_stat->hash_tfm = tfm;
174	crypt_stat->flags |= ECRYPTFS_STRUCT_INITIALIZED;
175
176	return 0;
177	}
178
179	/**
180	* ecryptfs_destroy_crypt_stat
181	* @crypt_stat: Pointer to the crypt_stat struct to initialize.
182	*
183	* Releases all memory associated with a crypt_stat struct.
184	*/
185	void ecryptfs_destroy_crypt_stat(struct ecryptfs_crypt_stat *crypt_stat)
186	{
187	struct ecryptfs_key_sig *key_sig, *key_sig_tmp;
188
189	crypto_free_skcipher(tfm: crypt_stat->tfm);
190	crypto_free_shash(tfm: 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(entry: &key_sig->crypt_stat_list);
194	kmem_cache_free(s: ecryptfs_key_sig_cache, objp: key_sig);
195	}
196	memset(crypt_stat, 0, sizeof(struct ecryptfs_crypt_stat));
197	}
198
199	void ecryptfs_destroy_mount_crypt_stat(
200	struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
201	{
202	struct ecryptfs_global_auth_tok *auth_tok, *auth_tok_tmp;
203
204	if (!(mount_crypt_stat->flags & ECRYPTFS_MOUNT_CRYPT_STAT_INITIALIZED))
205	return;
206	mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
207	list_for_each_entry_safe(auth_tok, auth_tok_tmp,
208	&mount_crypt_stat->global_auth_tok_list,
209	mount_crypt_stat_list) {
210	list_del(entry: &auth_tok->mount_crypt_stat_list);
211	if (!(auth_tok->flags & ECRYPTFS_AUTH_TOK_INVALID))
212	key_put(key: auth_tok->global_auth_tok_key);
213	kmem_cache_free(s: ecryptfs_global_auth_tok_cache, objp: auth_tok);
214	}
215	mutex_unlock(lock: &mount_crypt_stat->global_auth_tok_list_mutex);
216	memset(mount_crypt_stat, 0, sizeof(struct ecryptfs_mount_crypt_stat));
217	}
218
219	/**
220	* virt_to_scatterlist
221	* @addr: Virtual address
222	* @size: Size of data; should be an even multiple of the block size
223	* @sg: Pointer to scatterlist array; set to NULL to obtain only
224	* the number of scatterlist structs required in array
225	* @sg_size: Max array size
226	*
227	* Fills in a scatterlist array with page references for a passed
228	* virtual address.
229	*
230	* Returns the number of scatterlist structs in array used
231	*/
232	int virt_to_scatterlist(const void *addr, int size, struct scatterlist *sg,
233	int sg_size)
234	{
235	int i = 0;
236	struct page *pg;
237	int offset;
238	int remainder_of_page;
239
240	sg_init_table(sg, sg_size);
241
242	while (size > 0 && i < sg_size) {
243	pg = virt_to_page(addr);
244	offset = offset_in_page(addr);
245	sg_set_page(sg: &sg[i], page: pg, len: 0, offset);
246	remainder_of_page = PAGE_SIZE - offset;
247	if (size >= remainder_of_page) {
248	sg[i].length = remainder_of_page;
249	addr += remainder_of_page;
250	size -= remainder_of_page;
251	} else {
252	sg[i].length = size;
253	addr += size;
254	size = 0;
255	}
256	i++;
257	}
258	if (size > 0)
259	return -ENOMEM;
260	return i;
261	}
262
263	/**
264	* crypt_scatterlist
265	* @crypt_stat: Pointer to the crypt_stat struct to initialize.
266	* @dst_sg: Destination of the data after performing the crypto operation
267	* @src_sg: Data to be encrypted or decrypted
268	* @size: Length of data
269	* @iv: IV to use
270	* @op: ENCRYPT or DECRYPT to indicate the desired operation
271	*
272	* Returns the number of bytes encrypted or decrypted; negative value on error
273	*/
274	static int crypt_scatterlist(struct ecryptfs_crypt_stat *crypt_stat,
275	struct scatterlist *dst_sg,
276	struct scatterlist *src_sg, int size,
277	unsigned char *iv, int op)
278	{
279	struct skcipher_request *req = NULL;
280	DECLARE_CRYPTO_WAIT(ecr);
281	int rc = 0;
282
283	if (unlikely(ecryptfs_verbosity > 0)) {
284	ecryptfs_printk(KERN_DEBUG, "Key size [%zd]; key:\n",
285	crypt_stat->key_size);
286	ecryptfs_dump_hex(data: crypt_stat->key,
287	bytes: crypt_stat->key_size);
288	}
289
290	mutex_lock(&crypt_stat->cs_tfm_mutex);
291	req = skcipher_request_alloc(crypt_stat->tfm, GFP_NOFS);
292	if (!req) {
293	mutex_unlock(lock: &crypt_stat->cs_tfm_mutex);
294	rc = -ENOMEM;
295	goto out;
296	}
297
298	skcipher_request_set_callback(req,
299	CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
300	compl: crypto_req_done, data: &ecr);
301	/* Consider doing this once, when the file is opened */
302	if (!(crypt_stat->flags & ECRYPTFS_KEY_SET)) {
303	rc = crypto_skcipher_setkey(tfm: crypt_stat->tfm, key: crypt_stat->key,
304	keylen: crypt_stat->key_size);
305	if (rc) {
306	ecryptfs_printk(KERN_ERR,
307	"Error setting key; rc = [%d]\n",
308	rc);
309	mutex_unlock(lock: &crypt_stat->cs_tfm_mutex);
310	rc = -EINVAL;
311	goto out;
312	}
313	crypt_stat->flags |= ECRYPTFS_KEY_SET;
314	}
315	mutex_unlock(lock: &crypt_stat->cs_tfm_mutex);
316	skcipher_request_set_crypt(req, src: src_sg, dst: dst_sg, cryptlen: size, iv);
317	rc = op == ENCRYPT ? crypto_skcipher_encrypt(req) :
318	crypto_skcipher_decrypt(req);
319	rc = crypto_wait_req(err: rc, wait: &ecr);
320	out:
321	skcipher_request_free(req);
322	return rc;
323	}
324
325	/*
326	* lower_offset_for_page
327	*
328	* Convert an eCryptfs page index into a lower byte offset
329	*/
330	static loff_t lower_offset_for_page(struct ecryptfs_crypt_stat *crypt_stat,
331	struct folio *folio)
332	{
333	return ecryptfs_lower_header_size(crypt_stat) +
334	(loff_t)folio->index * PAGE_SIZE;
335	}
336
337	/**
338	* crypt_extent
339	* @crypt_stat: crypt_stat containing cryptographic context for the
340	* encryption operation
341	* @dst_page: The page to write the result into
342	* @src_page: The page to read from
343	* @page_index: The offset in the file (in units of PAGE_SIZE)
344	* @extent_offset: Page extent offset for use in generating IV
345	* @op: ENCRYPT or DECRYPT to indicate the desired operation
346	*
347	* Encrypts or decrypts one extent of data.
348	*
349	* Return zero on success; non-zero otherwise
350	*/
351	static int crypt_extent(struct ecryptfs_crypt_stat *crypt_stat,
352	struct page *dst_page,
353	struct page *src_page,
354	pgoff_t page_index,
355	unsigned long extent_offset, int op)
356	{
357	loff_t extent_base;
358	char extent_iv[ECRYPTFS_MAX_IV_BYTES];
359	struct scatterlist src_sg, dst_sg;
360	size_t extent_size = crypt_stat->extent_size;
361	int rc;
362
363	extent_base = (((loff_t)page_index) * (PAGE_SIZE / extent_size));
364	rc = ecryptfs_derive_iv(iv: extent_iv, crypt_stat,
365	offset: (extent_base + extent_offset));
366	if (rc) {
367	ecryptfs_printk(KERN_ERR, "Error attempting to derive IV for "
368	"extent [0x%.16llx]; rc = [%d]\n",
369	(unsigned long long)(extent_base + extent_offset), rc);
370	goto out;
371	}
372
373	sg_init_table(&src_sg, 1);
374	sg_init_table(&dst_sg, 1);
375
376	sg_set_page(sg: &src_sg, page: src_page, len: extent_size,
377	offset: extent_offset * extent_size);
378	sg_set_page(sg: &dst_sg, page: dst_page, len: extent_size,
379	offset: extent_offset * extent_size);
380
381	rc = crypt_scatterlist(crypt_stat, dst_sg: &dst_sg, src_sg: &src_sg, size: extent_size,
382	iv: extent_iv, op);
383	if (rc < 0) {
384	printk(KERN_ERR "%s: Error attempting to crypt page with "
385	"page_index = [%ld], extent_offset = [%ld]; "
386	"rc = [%d]\n", __func__, page_index, extent_offset, rc);
387	goto out;
388	}
389	rc = 0;
390	out:
391	return rc;
392	}
393
394	/**
395	* ecryptfs_encrypt_page
396	* @folio: Folio mapped from the eCryptfs inode for the file; contains
397	* decrypted content that needs to be encrypted (to a temporary
398	* page; not in place) and written out to the lower file
399	*
400	* Encrypt an eCryptfs page. This is done on a per-extent basis. Note
401	* that eCryptfs pages may straddle the lower pages -- for instance,
402	* if the file was created on a machine with an 8K page size
403	* (resulting in an 8K header), and then the file is copied onto a
404	* host with a 32K page size, then when reading page 0 of the eCryptfs
405	* file, 24K of page 0 of the lower file will be read and decrypted,
406	* and then 8K of page 1 of the lower file will be read and decrypted.
407	*
408	* Returns zero on success; negative on error
409	*/
410	int ecryptfs_encrypt_page(struct folio *folio)
411	{
412	struct inode *ecryptfs_inode;
413	struct ecryptfs_crypt_stat *crypt_stat;
414	char *enc_extent_virt;
415	struct page *enc_extent_page = NULL;
416	loff_t extent_offset;
417	loff_t lower_offset;
418	int rc = 0;
419
420	ecryptfs_inode = folio->mapping->host;
421	crypt_stat =
422	&(ecryptfs_inode_to_private(inode: ecryptfs_inode)->crypt_stat);
423	BUG_ON(!(crypt_stat->flags & ECRYPTFS_ENCRYPTED));
424	enc_extent_page = alloc_page(GFP_USER);
425	if (!enc_extent_page) {
426	rc = -ENOMEM;
427	ecryptfs_printk(KERN_ERR, "Error allocating memory for "
428	"encrypted extent\n");
429	goto out;
430	}
431
432	for (extent_offset = 0;
433	extent_offset < (PAGE_SIZE / crypt_stat->extent_size);
434	extent_offset++) {
435	rc = crypt_extent(crypt_stat, dst_page: enc_extent_page,
436	folio_page(folio, 0), page_index: folio->index,
437	extent_offset, ENCRYPT);
438	if (rc) {
439	printk(KERN_ERR "%s: Error encrypting extent; "
440	"rc = [%d]\n", __func__, rc);
441	goto out;
442	}
443	}
444
445	lower_offset = lower_offset_for_page(crypt_stat, folio);
446	enc_extent_virt = kmap_local_page(page: enc_extent_page);
447	rc = ecryptfs_write_lower(ecryptfs_inode, data: enc_extent_virt, offset: lower_offset,
448	PAGE_SIZE);
449	kunmap_local(enc_extent_virt);
450	if (rc < 0) {
451	ecryptfs_printk(KERN_ERR,
452	"Error attempting to write lower page; rc = [%d]\n",
453	rc);
454	goto out;
455	}
456	rc = 0;
457	out:
458	if (enc_extent_page) {
459	__free_page(enc_extent_page);
460	}
461	return rc;
462	}
463
464	/**
465	* ecryptfs_decrypt_page
466	* @folio: Folio mapped from the eCryptfs inode for the file; data read
467	* and decrypted from the lower file will be written into this
468	* page
469	*
470	* Decrypt an eCryptfs page. This is done on a per-extent basis. Note
471	* that eCryptfs pages may straddle the lower pages -- for instance,
472	* if the file was created on a machine with an 8K page size
473	* (resulting in an 8K header), and then the file is copied onto a
474	* host with a 32K page size, then when reading page 0 of the eCryptfs
475	* file, 24K of page 0 of the lower file will be read and decrypted,
476	* and then 8K of page 1 of the lower file will be read and decrypted.
477	*
478	* Returns zero on success; negative on error
479	*/
480	int ecryptfs_decrypt_page(struct folio *folio)
481	{
482	struct inode *ecryptfs_inode;
483	struct ecryptfs_crypt_stat *crypt_stat;
484	char *page_virt;
485	unsigned long extent_offset;
486	loff_t lower_offset;
487	int rc = 0;
488
489	ecryptfs_inode = folio->mapping->host;
490	crypt_stat =
491	&(ecryptfs_inode_to_private(inode: ecryptfs_inode)->crypt_stat);
492	BUG_ON(!(crypt_stat->flags & ECRYPTFS_ENCRYPTED));
493
494	lower_offset = lower_offset_for_page(crypt_stat, folio);
495	page_virt = kmap_local_folio(folio, offset: 0);
496	rc = ecryptfs_read_lower(data: page_virt, offset: lower_offset, PAGE_SIZE,
497	ecryptfs_inode);
498	kunmap_local(page_virt);
499	if (rc < 0) {
500	ecryptfs_printk(KERN_ERR,
501	"Error attempting to read lower page; rc = [%d]\n",
502	rc);
503	goto out;
504	}
505
506	for (extent_offset = 0;
507	extent_offset < (PAGE_SIZE / crypt_stat->extent_size);
508	extent_offset++) {
509	struct page *page = folio_page(folio, 0);
510	rc = crypt_extent(crypt_stat, dst_page: page, src_page: page, page_index: folio->index,
511	extent_offset, DECRYPT);
512	if (rc) {
513	printk(KERN_ERR "%s: Error decrypting extent; "
514	"rc = [%d]\n", __func__, rc);
515	goto out;
516	}
517	}
518	out:
519	return rc;
520	}
521
522	#define ECRYPTFS_MAX_SCATTERLIST_LEN 4
523
524	/**
525	* ecryptfs_init_crypt_ctx
526	* @crypt_stat: Uninitialized crypt stats structure
527	*
528	* Initialize the crypto context.
529	*
530	* TODO: Performance: Keep a cache of initialized cipher contexts;
531	* only init if needed
532	*/
533	int ecryptfs_init_crypt_ctx(struct ecryptfs_crypt_stat *crypt_stat)
534	{
535	char *full_alg_name;
536	int rc = -EINVAL;
537
538	ecryptfs_printk(KERN_DEBUG,
539	"Initializing cipher [%s]; strlen = [%d]; "
540	"key_size_bits = [%zd]\n",
541	crypt_stat->cipher, (int)strlen(crypt_stat->cipher),
542	crypt_stat->key_size << 3);
543	mutex_lock(&crypt_stat->cs_tfm_mutex);
544	if (crypt_stat->tfm) {
545	rc = 0;
546	goto out_unlock;
547	}
548	rc = ecryptfs_crypto_api_algify_cipher_name(algified_name: &full_alg_name,
549	cipher_name: crypt_stat->cipher, chaining_modifier: "cbc");
550	if (rc)
551	goto out_unlock;
552	crypt_stat->tfm = crypto_alloc_skcipher(alg_name: full_alg_name, type: 0, mask: 0);
553	if (IS_ERR(ptr: crypt_stat->tfm)) {
554	rc = PTR_ERR(ptr: crypt_stat->tfm);
555	crypt_stat->tfm = NULL;
556	ecryptfs_printk(KERN_ERR, "cryptfs: init_crypt_ctx(): "
557	"Error initializing cipher [%s]\n",
558	full_alg_name);
559	goto out_free;
560	}
561	crypto_skcipher_set_flags(tfm: crypt_stat->tfm,
562	CRYPTO_TFM_REQ_FORBID_WEAK_KEYS);
563	rc = 0;
564	out_free:
565	kfree(objp: full_alg_name);
566	out_unlock:
567	mutex_unlock(lock: &crypt_stat->cs_tfm_mutex);
568	return rc;
569	}
570
571	static void set_extent_mask_and_shift(struct ecryptfs_crypt_stat *crypt_stat)
572	{
573	int extent_size_tmp;
574
575	crypt_stat->extent_mask = 0xFFFFFFFF;
576	crypt_stat->extent_shift = 0;
577	if (crypt_stat->extent_size == 0)
578	return;
579	extent_size_tmp = crypt_stat->extent_size;
580	while ((extent_size_tmp & 0x01) == 0) {
581	extent_size_tmp >>= 1;
582	crypt_stat->extent_mask <<= 1;
583	crypt_stat->extent_shift++;
584	}
585	}
586
587	void ecryptfs_set_default_sizes(struct ecryptfs_crypt_stat *crypt_stat)
588	{
589	/* Default values; may be overwritten as we are parsing the
590	* packets. */
591	crypt_stat->extent_size = ECRYPTFS_DEFAULT_EXTENT_SIZE;
592	set_extent_mask_and_shift(crypt_stat);
593	crypt_stat->iv_bytes = ECRYPTFS_DEFAULT_IV_BYTES;
594	if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
595	crypt_stat->metadata_size = ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
596	else {
597	if (PAGE_SIZE <= ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE)
598	crypt_stat->metadata_size =
599	ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
600	else
601	crypt_stat->metadata_size = PAGE_SIZE;
602	}
603	}
604
605	/*
606	* ecryptfs_compute_root_iv
607	*
608	* On error, sets the root IV to all 0's.
609	*/
610	int ecryptfs_compute_root_iv(struct ecryptfs_crypt_stat *crypt_stat)
611	{
612	int rc = 0;
613	char dst[MD5_DIGEST_SIZE];
614
615	BUG_ON(crypt_stat->iv_bytes > MD5_DIGEST_SIZE);
616	BUG_ON(crypt_stat->iv_bytes <= 0);
617	if (!(crypt_stat->flags & ECRYPTFS_KEY_VALID)) {
618	rc = -EINVAL;
619	ecryptfs_printk(KERN_WARNING, "Session key not valid; "
620	"cannot generate root IV\n");
621	goto out;
622	}
623	rc = ecryptfs_calculate_md5(dst, crypt_stat, src: crypt_stat->key,
624	len: crypt_stat->key_size);
625	if (rc) {
626	ecryptfs_printk(KERN_WARNING, "Error attempting to compute "
627	"MD5 while generating root IV\n");
628	goto out;
629	}
630	memcpy(crypt_stat->root_iv, dst, crypt_stat->iv_bytes);
631	out:
632	if (rc) {
633	memset(crypt_stat->root_iv, 0, crypt_stat->iv_bytes);
634	crypt_stat->flags |= ECRYPTFS_SECURITY_WARNING;
635	}
636	return rc;
637	}
638
639	static void ecryptfs_generate_new_key(struct ecryptfs_crypt_stat *crypt_stat)
640	{
641	get_random_bytes(buf: crypt_stat->key, len: crypt_stat->key_size);
642	crypt_stat->flags |= ECRYPTFS_KEY_VALID;
643	ecryptfs_compute_root_iv(crypt_stat);
644	if (unlikely(ecryptfs_verbosity > 0)) {
645	ecryptfs_printk(KERN_DEBUG, "Generated new session key:\n");
646	ecryptfs_dump_hex(data: crypt_stat->key,
647	bytes: crypt_stat->key_size);
648	}
649	}
650
651	/**
652	* ecryptfs_copy_mount_wide_flags_to_inode_flags
653	* @crypt_stat: The inode's cryptographic context
654	* @mount_crypt_stat: The mount point's cryptographic context
655	*
656	* This function propagates the mount-wide flags to individual inode
657	* flags.
658	*/
659	static void ecryptfs_copy_mount_wide_flags_to_inode_flags(
660	struct ecryptfs_crypt_stat *crypt_stat,
661	struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
662	{
663	if (mount_crypt_stat->flags & ECRYPTFS_XATTR_METADATA_ENABLED)
664	crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
665	if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
666	crypt_stat->flags |= ECRYPTFS_VIEW_AS_ENCRYPTED;
667	if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) {
668	crypt_stat->flags |= ECRYPTFS_ENCRYPT_FILENAMES;
669	if (mount_crypt_stat->flags
670	& ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK)
671	crypt_stat->flags |= ECRYPTFS_ENCFN_USE_MOUNT_FNEK;
672	else if (mount_crypt_stat->flags
673	& ECRYPTFS_GLOBAL_ENCFN_USE_FEK)
674	crypt_stat->flags |= ECRYPTFS_ENCFN_USE_FEK;
675	}
676	}
677
678	static int ecryptfs_copy_mount_wide_sigs_to_inode_sigs(
679	struct ecryptfs_crypt_stat *crypt_stat,
680	struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
681	{
682	struct ecryptfs_global_auth_tok *global_auth_tok;
683	int rc = 0;
684
685	mutex_lock(&crypt_stat->keysig_list_mutex);
686	mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
687
688	list_for_each_entry(global_auth_tok,
689	&mount_crypt_stat->global_auth_tok_list,
690	mount_crypt_stat_list) {
691	if (global_auth_tok->flags & ECRYPTFS_AUTH_TOK_FNEK)
692	continue;
693	rc = ecryptfs_add_keysig(crypt_stat, sig: global_auth_tok->sig);
694	if (rc) {
695	printk(KERN_ERR "Error adding keysig; rc = [%d]\n", rc);
696	goto out;
697	}
698	}
699
700	out:
701	mutex_unlock(lock: &mount_crypt_stat->global_auth_tok_list_mutex);
702	mutex_unlock(lock: &crypt_stat->keysig_list_mutex);
703	return rc;
704	}
705
706	/**
707	* ecryptfs_set_default_crypt_stat_vals
708	* @crypt_stat: The inode's cryptographic context
709	* @mount_crypt_stat: The mount point's cryptographic context
710	*
711	* Default values in the event that policy does not override them.
712	*/
713	static void ecryptfs_set_default_crypt_stat_vals(
714	struct ecryptfs_crypt_stat *crypt_stat,
715	struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
716	{
717	ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
718	mount_crypt_stat);
719	ecryptfs_set_default_sizes(crypt_stat);
720	strcpy(p: crypt_stat->cipher, ECRYPTFS_DEFAULT_CIPHER);
721	crypt_stat->key_size = ECRYPTFS_DEFAULT_KEY_BYTES;
722	crypt_stat->flags &= ~(ECRYPTFS_KEY_VALID);
723	crypt_stat->file_version = ECRYPTFS_FILE_VERSION;
724	crypt_stat->mount_crypt_stat = mount_crypt_stat;
725	}
726
727	/**
728	* ecryptfs_new_file_context
729	* @ecryptfs_inode: The eCryptfs inode
730	*
731	* If the crypto context for the file has not yet been established,
732	* this is where we do that. Establishing a new crypto context
733	* involves the following decisions:
734	* - What cipher to use?
735	* - What set of authentication tokens to use?
736	* Here we just worry about getting enough information into the
737	* authentication tokens so that we know that they are available.
738	* We associate the available authentication tokens with the new file
739	* via the set of signatures in the crypt_stat struct. Later, when
740	* the headers are actually written out, we may again defer to
741	* userspace to perform the encryption of the session key; for the
742	* foreseeable future, this will be the case with public key packets.
743	*
744	* Returns zero on success; non-zero otherwise
745	*/
746	int ecryptfs_new_file_context(struct inode *ecryptfs_inode)
747	{
748	struct ecryptfs_crypt_stat *crypt_stat =
749	&ecryptfs_inode_to_private(inode: ecryptfs_inode)->crypt_stat;
750	struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
751	&ecryptfs_superblock_to_private(
752	sb: ecryptfs_inode->i_sb)->mount_crypt_stat;
753	int cipher_name_len;
754	int rc = 0;
755
756	ecryptfs_set_default_crypt_stat_vals(crypt_stat, mount_crypt_stat);
757	crypt_stat->flags |= (ECRYPTFS_ENCRYPTED | ECRYPTFS_KEY_VALID);
758	ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
759	mount_crypt_stat);
760	rc = ecryptfs_copy_mount_wide_sigs_to_inode_sigs(crypt_stat,
761	mount_crypt_stat);
762	if (rc) {
763	printk(KERN_ERR "Error attempting to copy mount-wide key sigs "
764	"to the inode key sigs; rc = [%d]\n", rc);
765	goto out;
766	}
767	cipher_name_len =
768	strlen(mount_crypt_stat->global_default_cipher_name);
769	memcpy(crypt_stat->cipher,
770	mount_crypt_stat->global_default_cipher_name,
771	cipher_name_len);
772	crypt_stat->cipher[cipher_name_len] = '\0';
773	crypt_stat->key_size =
774	mount_crypt_stat->global_default_cipher_key_size;
775	ecryptfs_generate_new_key(crypt_stat);
776	rc = ecryptfs_init_crypt_ctx(crypt_stat);
777	if (rc)
778	ecryptfs_printk(KERN_ERR, "Error initializing cryptographic "
779	"context for cipher [%s]: rc = [%d]\n",
780	crypt_stat->cipher, rc);
781	out:
782	return rc;
783	}
784
785	/**
786	* ecryptfs_validate_marker - check for the ecryptfs marker
787	* @data: The data block in which to check
788	*
789	* Returns zero if marker found; -EINVAL if not found
790	*/
791	static int ecryptfs_validate_marker(char *data)
792	{
793	u32 m_1, m_2;
794
795	m_1 = get_unaligned_be32(p: data);
796	m_2 = get_unaligned_be32(p: data + 4);
797	if ((m_1 ^ MAGIC_ECRYPTFS_MARKER) == m_2)
798	return 0;
799	ecryptfs_printk(KERN_DEBUG, "m_1 = [0x%.8x]; m_2 = [0x%.8x]; "
800	"MAGIC_ECRYPTFS_MARKER = [0x%.8x]\n", m_1, m_2,
801	MAGIC_ECRYPTFS_MARKER);
802	ecryptfs_printk(KERN_DEBUG, "(m_1 ^ MAGIC_ECRYPTFS_MARKER) = "
803	"[0x%.8x]\n", (m_1 ^ MAGIC_ECRYPTFS_MARKER));
804	return -EINVAL;
805	}
806
807	struct ecryptfs_flag_map_elem {
808	u32 file_flag;
809	u32 local_flag;
810	};
811
812	/* Add support for additional flags by adding elements here. */
813	static struct ecryptfs_flag_map_elem ecryptfs_flag_map[] = {
814	{0x00000001, ECRYPTFS_ENABLE_HMAC},
815	{0x00000002, ECRYPTFS_ENCRYPTED},
816	{0x00000004, ECRYPTFS_METADATA_IN_XATTR},
817	{0x00000008, ECRYPTFS_ENCRYPT_FILENAMES}
818	};
819
820	/**
821	* ecryptfs_process_flags
822	* @crypt_stat: The cryptographic context
823	* @page_virt: Source data to be parsed
824	* @bytes_read: Updated with the number of bytes read
825	*/
826	static void ecryptfs_process_flags(struct ecryptfs_crypt_stat *crypt_stat,
827	char *page_virt, int *bytes_read)
828	{
829	int i;
830	u32 flags;
831
832	flags = get_unaligned_be32(p: page_virt);
833	for (i = 0; i < ARRAY_SIZE(ecryptfs_flag_map); i++)
834	if (flags & ecryptfs_flag_map[i].file_flag) {
835	crypt_stat->flags |= ecryptfs_flag_map[i].local_flag;
836	} else
837	crypt_stat->flags &= ~(ecryptfs_flag_map[i].local_flag);
838	/* Version is in top 8 bits of the 32-bit flag vector */
839	crypt_stat->file_version = ((flags >> 24) & 0xFF);
840	(*bytes_read) = 4;
841	}
842
843	/**
844	* write_ecryptfs_marker
845	* @page_virt: The pointer to in a page to begin writing the marker
846	* @written: Number of bytes written
847	*
848	* Marker = 0x3c81b7f5
849	*/
850	static void write_ecryptfs_marker(char *page_virt, size_t *written)
851	{
852	u32 m_1, m_2;
853
854	get_random_bytes(buf: &m_1, len: (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2));
855	m_2 = (m_1 ^ MAGIC_ECRYPTFS_MARKER);
856	put_unaligned_be32(val: m_1, p: page_virt);
857	page_virt += (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2);
858	put_unaligned_be32(val: m_2, p: page_virt);
859	(*written) = MAGIC_ECRYPTFS_MARKER_SIZE_BYTES;
860	}
861
862	void ecryptfs_write_crypt_stat_flags(char *page_virt,
863	struct ecryptfs_crypt_stat *crypt_stat,
864	size_t *written)
865	{
866	u32 flags = 0;
867	int i;
868
869	for (i = 0; i < ARRAY_SIZE(ecryptfs_flag_map); i++)
870	if (crypt_stat->flags & ecryptfs_flag_map[i].local_flag)
871	flags |= ecryptfs_flag_map[i].file_flag;
872	/* Version is in top 8 bits of the 32-bit flag vector */
873	flags |= ((((u8)crypt_stat->file_version) << 24) & 0xFF000000);
874	put_unaligned_be32(val: flags, p: page_virt);
875	(*written) = 4;
876	}
877
878	struct ecryptfs_cipher_code_str_map_elem {
879	char cipher_str[16];
880	u8 cipher_code;
881	};
882
883	/* Add support for additional ciphers by adding elements here. The
884	* cipher_code is whatever OpenPGP applications use to identify the
885	* ciphers. List in order of probability. */
886	static struct ecryptfs_cipher_code_str_map_elem
887	ecryptfs_cipher_code_str_map[] = {
888	{"aes",RFC2440_CIPHER_AES_128 },
889	{"blowfish", RFC2440_CIPHER_BLOWFISH},
890	{"des3_ede", RFC2440_CIPHER_DES3_EDE},
891	{"cast5", RFC2440_CIPHER_CAST_5},
892	{"twofish", RFC2440_CIPHER_TWOFISH},
893	{"cast6", RFC2440_CIPHER_CAST_6},
894	{"aes", RFC2440_CIPHER_AES_192},
895	{"aes", RFC2440_CIPHER_AES_256}
896	};
897
898	/**
899	* ecryptfs_code_for_cipher_string
900	* @cipher_name: The string alias for the cipher
901	* @key_bytes: Length of key in bytes; used for AES code selection
902	*
903	* Returns zero on no match, or the cipher code on match
904	*/
905	u8 ecryptfs_code_for_cipher_string(char *cipher_name, size_t key_bytes)
906	{
907	int i;
908	u8 code = 0;
909	struct ecryptfs_cipher_code_str_map_elem *map =
910	ecryptfs_cipher_code_str_map;
911
912	if (strcmp(cipher_name, "aes") == 0) {
913	switch (key_bytes) {
914	case 16:
915	code = RFC2440_CIPHER_AES_128;
916	break;
917	case 24:
918	code = RFC2440_CIPHER_AES_192;
919	break;
920	case 32:
921	code = RFC2440_CIPHER_AES_256;
922	}
923	} else {
924	for (i = 0; i < ARRAY_SIZE(ecryptfs_cipher_code_str_map); i++)
925	if (strcmp(cipher_name, map[i].cipher_str) == 0) {
926	code = map[i].cipher_code;
927	break;
928	}
929	}
930	return code;
931	}
932
933	/**
934	* ecryptfs_cipher_code_to_string
935	* @str: Destination to write out the cipher name
936	* @cipher_code: The code to convert to cipher name string
937	*
938	* Returns zero on success
939	*/
940	int ecryptfs_cipher_code_to_string(char *str, u8 cipher_code)
941	{
942	int rc = 0;
943	int i;
944
945	str[0] = '\0';
946	for (i = 0; i < ARRAY_SIZE(ecryptfs_cipher_code_str_map); i++)
947	if (cipher_code == ecryptfs_cipher_code_str_map[i].cipher_code)
948	strcpy(p: str, q: ecryptfs_cipher_code_str_map[i].cipher_str);
949	if (str[0] == '\0') {
950	ecryptfs_printk(KERN_WARNING, "Cipher code not recognized: "
951	"[%d]\n", cipher_code);
952	rc = -EINVAL;
953	}
954	return rc;
955	}
956
957	int ecryptfs_read_and_validate_header_region(struct inode *inode)
958	{
959	u8 file_size[ECRYPTFS_SIZE_AND_MARKER_BYTES];
960	u8 *marker = file_size + ECRYPTFS_FILE_SIZE_BYTES;
961	int rc;
962
963	rc = ecryptfs_read_lower(data: file_size, offset: 0, ECRYPTFS_SIZE_AND_MARKER_BYTES,
964	ecryptfs_inode: inode);
965	if (rc < 0)
966	return rc;
967	else if (rc < ECRYPTFS_SIZE_AND_MARKER_BYTES)
968	return -EINVAL;
969	rc = ecryptfs_validate_marker(data: marker);
970	if (!rc)
971	ecryptfs_i_size_init(page_virt: file_size, inode);
972	return rc;
973	}
974
975	void
976	ecryptfs_write_header_metadata(char *virt,
977	struct ecryptfs_crypt_stat *crypt_stat,
978	size_t *written)
979	{
980	u32 header_extent_size;
981	u16 num_header_extents_at_front;
982
983	header_extent_size = (u32)crypt_stat->extent_size;
984	num_header_extents_at_front =
985	(u16)(crypt_stat->metadata_size / crypt_stat->extent_size);
986	put_unaligned_be32(val: header_extent_size, p: virt);
987	virt += 4;
988	put_unaligned_be16(val: num_header_extents_at_front, p: virt);
989	(*written) = 6;
990	}
991
992	struct kmem_cache *ecryptfs_header_cache;
993
994	/**
995	* ecryptfs_write_headers_virt
996	* @page_virt: The virtual address to write the headers to
997	* @max: The size of memory allocated at page_virt
998	* @size: Set to the number of bytes written by this function
999	* @crypt_stat: The cryptographic context
1000	* @ecryptfs_dentry: The eCryptfs dentry
1001	*
1002	* Format version: 1
1003	*
1004	* Header Extent:
1005	* Octets 0-7: Unencrypted file size (big-endian)
1006	* Octets 8-15: eCryptfs special marker
1007	* Octets 16-19: Flags
1008	* Octet 16: File format version number (between 0 and 255)
1009	* Octets 17-18: Reserved
1010	* Octet 19: Bit 1 (lsb): Reserved
1011	* Bit 2: Encrypted?
1012	* Bits 3-8: Reserved
1013	* Octets 20-23: Header extent size (big-endian)
1014	* Octets 24-25: Number of header extents at front of file
1015	* (big-endian)
1016	* Octet 26: Begin RFC 2440 authentication token packet set
1017	* Data Extent 0:
1018	* Lower data (CBC encrypted)
1019	* Data Extent 1:
1020	* Lower data (CBC encrypted)
1021	* ...
1022	*
1023	* Returns zero on success
1024	*/
1025	static int ecryptfs_write_headers_virt(char *page_virt, size_t max,
1026	size_t *size,
1027	struct ecryptfs_crypt_stat *crypt_stat,
1028	struct dentry *ecryptfs_dentry)
1029	{
1030	int rc;
1031	size_t written;
1032	size_t offset;
1033
1034	offset = ECRYPTFS_FILE_SIZE_BYTES;
1035	write_ecryptfs_marker(page_virt: (page_virt + offset), written: &written);
1036	offset += written;
1037	ecryptfs_write_crypt_stat_flags(page_virt: (page_virt + offset), crypt_stat,
1038	written: &written);
1039	offset += written;
1040	ecryptfs_write_header_metadata(virt: (page_virt + offset), crypt_stat,
1041	written: &written);
1042	offset += written;
1043	rc = ecryptfs_generate_key_packet_set(dest_base: (page_virt + offset), crypt_stat,
1044	ecryptfs_dentry, len: &written,
1045	max: max - offset);
1046	if (rc)
1047	ecryptfs_printk(KERN_WARNING, "Error generating key packet "
1048	"set; rc = [%d]\n", rc);
1049	if (size) {
1050	offset += written;
1051	*size = offset;
1052	}
1053	return rc;
1054	}
1055
1056	static int
1057	ecryptfs_write_metadata_to_contents(struct inode *ecryptfs_inode,
1058	char *virt, size_t virt_len)
1059	{
1060	int rc;
1061
1062	rc = ecryptfs_write_lower(ecryptfs_inode, data: virt,
1063	offset: 0, size: virt_len);
1064	if (rc < 0)
1065	printk(KERN_ERR "%s: Error attempting to write header "
1066	"information to lower file; rc = [%d]\n", __func__, rc);
1067	else
1068	rc = 0;
1069	return rc;
1070	}
1071
1072	static int
1073	ecryptfs_write_metadata_to_xattr(struct dentry *ecryptfs_dentry,
1074	struct inode *ecryptfs_inode,
1075	char *page_virt, size_t size)
1076	{
1077	int rc;
1078	struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry: ecryptfs_dentry);
1079	struct inode *lower_inode = d_inode(dentry: lower_dentry);
1080
1081	if (!(lower_inode->i_opflags & IOP_XATTR)) {
1082	rc = -EOPNOTSUPP;
1083	goto out;
1084	}
1085
1086	inode_lock(inode: lower_inode);
1087	rc = __vfs_setxattr(&nop_mnt_idmap, lower_dentry, lower_inode,
1088	ECRYPTFS_XATTR_NAME, page_virt, size, 0);
1089	if (!rc && ecryptfs_inode)
1090	fsstack_copy_attr_all(dest: ecryptfs_inode, src: lower_inode);
1091	inode_unlock(inode: lower_inode);
1092	out:
1093	return rc;
1094	}
1095
1096	static unsigned long ecryptfs_get_zeroed_pages(gfp_t gfp_mask,
1097	unsigned int order)
1098	{
1099	struct page *page;
1100
1101	page = alloc_pages(gfp_mask | __GFP_ZERO, order);
1102	if (page)
1103	return (unsigned long) page_address(page);
1104	return 0;
1105	}
1106
1107	/**
1108	* ecryptfs_write_metadata
1109	* @ecryptfs_dentry: The eCryptfs dentry, which should be negative
1110	* @ecryptfs_inode: The newly created eCryptfs inode
1111	*
1112	* Write the file headers out. This will likely involve a userspace
1113	* callout, in which the session key is encrypted with one or more
1114	* public keys and/or the passphrase necessary to do the encryption is
1115	* retrieved via a prompt. Exactly what happens at this point should
1116	* be policy-dependent.
1117	*
1118	* Returns zero on success; non-zero on error
1119	*/
1120	int ecryptfs_write_metadata(struct dentry *ecryptfs_dentry,
1121	struct inode *ecryptfs_inode)
1122	{
1123	struct ecryptfs_crypt_stat *crypt_stat =
1124	&ecryptfs_inode_to_private(inode: ecryptfs_inode)->crypt_stat;
1125	unsigned int order;
1126	char *virt;
1127	size_t virt_len;
1128	size_t size = 0;
1129	int rc = 0;
1130
1131	if (likely(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
1132	if (!(crypt_stat->flags & ECRYPTFS_KEY_VALID)) {
1133	printk(KERN_ERR "Key is invalid; bailing out\n");
1134	rc = -EINVAL;
1135	goto out;
1136	}
1137	} else {
1138	printk(KERN_WARNING "%s: Encrypted flag not set\n",
1139	__func__);
1140	rc = -EINVAL;
1141	goto out;
1142	}
1143	virt_len = crypt_stat->metadata_size;
1144	order = get_order(size: virt_len);
1145	/* Released in this function */
1146	virt = (char *)ecryptfs_get_zeroed_pages(GFP_KERNEL, order);
1147	if (!virt) {
1148	printk(KERN_ERR "%s: Out of memory\n", __func__);
1149	rc = -ENOMEM;
1150	goto out;
1151	}
1152	/* Zeroed page ensures the in-header unencrypted i_size is set to 0 */
1153	rc = ecryptfs_write_headers_virt(page_virt: virt, max: virt_len, size: &size, crypt_stat,
1154	ecryptfs_dentry);
1155	if (unlikely(rc)) {
1156	printk(KERN_ERR "%s: Error whilst writing headers; rc = [%d]\n",
1157	__func__, rc);
1158	goto out_free;
1159	}
1160	if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
1161	rc = ecryptfs_write_metadata_to_xattr(ecryptfs_dentry, ecryptfs_inode,
1162	page_virt: virt, size);
1163	else
1164	rc = ecryptfs_write_metadata_to_contents(ecryptfs_inode, virt,
1165	virt_len);
1166	if (rc) {
1167	printk(KERN_ERR "%s: Error writing metadata out to lower file; "
1168	"rc = [%d]\n", __func__, rc);
1169	goto out_free;
1170	}
1171	out_free:
1172	free_pages(addr: (unsigned long)virt, order);
1173	out:
1174	return rc;
1175	}
1176
1177	#define ECRYPTFS_DONT_VALIDATE_HEADER_SIZE 0
1178	#define ECRYPTFS_VALIDATE_HEADER_SIZE 1
1179	static int parse_header_metadata(struct ecryptfs_crypt_stat *crypt_stat,
1180	char *virt, int *bytes_read,
1181	int validate_header_size)
1182	{
1183	int rc = 0;
1184	u32 header_extent_size;
1185	u16 num_header_extents_at_front;
1186
1187	header_extent_size = get_unaligned_be32(p: virt);
1188	virt += sizeof(__be32);
1189	num_header_extents_at_front = get_unaligned_be16(p: virt);
1190	crypt_stat->metadata_size = (((size_t)num_header_extents_at_front
1191	* (size_t)header_extent_size));
1192	(*bytes_read) = (sizeof(__be32) + sizeof(__be16));
1193	if ((validate_header_size == ECRYPTFS_VALIDATE_HEADER_SIZE)
1194	&& (crypt_stat->metadata_size
1195	< ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE)) {
1196	rc = -EINVAL;
1197	printk(KERN_WARNING "Invalid header size: [%zd]\n",
1198	crypt_stat->metadata_size);
1199	}
1200	return rc;
1201	}
1202
1203	/**
1204	* set_default_header_data
1205	* @crypt_stat: The cryptographic context
1206	*
1207	* For version 0 file format; this function is only for backwards
1208	* compatibility for files created with the prior versions of
1209	* eCryptfs.
1210	*/
1211	static void set_default_header_data(struct ecryptfs_crypt_stat *crypt_stat)
1212	{
1213	crypt_stat->metadata_size = ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
1214	}
1215
1216	void ecryptfs_i_size_init(const char *page_virt, struct inode *inode)
1217	{
1218	struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
1219	struct ecryptfs_crypt_stat *crypt_stat;
1220	u64 file_size;
1221
1222	crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
1223	mount_crypt_stat =
1224	&ecryptfs_superblock_to_private(sb: inode->i_sb)->mount_crypt_stat;
1225	if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED) {
1226	file_size = i_size_read(inode: ecryptfs_inode_to_lower(inode));
1227	if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
1228	file_size += crypt_stat->metadata_size;
1229	} else
1230	file_size = get_unaligned_be64(p: page_virt);
1231	i_size_write(inode, i_size: (loff_t)file_size);
1232	crypt_stat->flags |= ECRYPTFS_I_SIZE_INITIALIZED;
1233	}
1234
1235	/**
1236	* ecryptfs_read_headers_virt
1237	* @page_virt: The virtual address into which to read the headers
1238	* @crypt_stat: The cryptographic context
1239	* @ecryptfs_dentry: The eCryptfs dentry
1240	* @validate_header_size: Whether to validate the header size while reading
1241	*
1242	* Read/parse the header data. The header format is detailed in the
1243	* comment block for the ecryptfs_write_headers_virt() function.
1244	*
1245	* Returns zero on success
1246	*/
1247	static int ecryptfs_read_headers_virt(char *page_virt,
1248	struct ecryptfs_crypt_stat *crypt_stat,
1249	struct dentry *ecryptfs_dentry,
1250	int validate_header_size)
1251	{
1252	int rc = 0;
1253	int offset;
1254	int bytes_read;
1255
1256	ecryptfs_set_default_sizes(crypt_stat);
1257	crypt_stat->mount_crypt_stat = &ecryptfs_superblock_to_private(
1258	sb: ecryptfs_dentry->d_sb)->mount_crypt_stat;
1259	offset = ECRYPTFS_FILE_SIZE_BYTES;
1260	rc = ecryptfs_validate_marker(data: page_virt + offset);
1261	if (rc)
1262	goto out;
1263	if (!(crypt_stat->flags & ECRYPTFS_I_SIZE_INITIALIZED))
1264	ecryptfs_i_size_init(page_virt, inode: d_inode(dentry: ecryptfs_dentry));
1265	offset += MAGIC_ECRYPTFS_MARKER_SIZE_BYTES;
1266	ecryptfs_process_flags(crypt_stat, page_virt: (page_virt + offset), bytes_read: &bytes_read);
1267	if (crypt_stat->file_version > ECRYPTFS_SUPPORTED_FILE_VERSION) {
1268	ecryptfs_printk(KERN_WARNING, "File version is [%d]; only "
1269	"file version [%d] is supported by this "
1270	"version of eCryptfs\n",
1271	crypt_stat->file_version,
1272	ECRYPTFS_SUPPORTED_FILE_VERSION);
1273	rc = -EINVAL;
1274	goto out;
1275	}
1276	offset += bytes_read;
1277	if (crypt_stat->file_version >= 1) {
1278	rc = parse_header_metadata(crypt_stat, virt: (page_virt + offset),
1279	bytes_read: &bytes_read, validate_header_size);
1280	if (rc) {
1281	ecryptfs_printk(KERN_WARNING, "Error reading header "
1282	"metadata; rc = [%d]\n", rc);
1283	}
1284	offset += bytes_read;
1285	} else
1286	set_default_header_data(crypt_stat);
1287	rc = ecryptfs_parse_packet_set(crypt_stat, src: (page_virt + offset),
1288	ecryptfs_dentry);
1289	out:
1290	return rc;
1291	}
1292
1293	/**
1294	* ecryptfs_read_xattr_region
1295	* @page_virt: The vitual address into which to read the xattr data
1296	* @ecryptfs_inode: The eCryptfs inode
1297	*
1298	* Attempts to read the crypto metadata from the extended attribute
1299	* region of the lower file.
1300	*
1301	* Returns zero on success; non-zero on error
1302	*/
1303	int ecryptfs_read_xattr_region(char *page_virt, struct inode *ecryptfs_inode)
1304	{
1305	struct dentry *lower_dentry =
1306	ecryptfs_inode_to_private(inode: ecryptfs_inode)->lower_file->f_path.dentry;
1307	ssize_t size;
1308	int rc = 0;
1309
1310	size = ecryptfs_getxattr_lower(lower_dentry,
1311	lower_inode: ecryptfs_inode_to_lower(inode: ecryptfs_inode),
1312	ECRYPTFS_XATTR_NAME,
1313	value: page_virt, ECRYPTFS_DEFAULT_EXTENT_SIZE);
1314	if (size < 0) {
1315	if (unlikely(ecryptfs_verbosity > 0))
1316	printk(KERN_INFO "Error attempting to read the [%s] "
1317	"xattr from the lower file; return value = "
1318	"[%zd]\n", ECRYPTFS_XATTR_NAME, size);
1319	rc = -EINVAL;
1320	goto out;
1321	}
1322	out:
1323	return rc;
1324	}
1325
1326	int ecryptfs_read_and_validate_xattr_region(struct dentry *dentry,
1327	struct inode *inode)
1328	{
1329	u8 file_size[ECRYPTFS_SIZE_AND_MARKER_BYTES];
1330	u8 *marker = file_size + ECRYPTFS_FILE_SIZE_BYTES;
1331	int rc;
1332
1333	rc = ecryptfs_getxattr_lower(lower_dentry: ecryptfs_dentry_to_lower(dentry),
1334	lower_inode: ecryptfs_inode_to_lower(inode),
1335	ECRYPTFS_XATTR_NAME, value: file_size,
1336	ECRYPTFS_SIZE_AND_MARKER_BYTES);
1337	if (rc < 0)
1338	return rc;
1339	else if (rc < ECRYPTFS_SIZE_AND_MARKER_BYTES)
1340	return -EINVAL;
1341	rc = ecryptfs_validate_marker(data: marker);
1342	if (!rc)
1343	ecryptfs_i_size_init(page_virt: file_size, inode);
1344	return rc;
1345	}
1346
1347	/*
1348	* ecryptfs_read_metadata
1349	*
1350	* Common entry point for reading file metadata. From here, we could
1351	* retrieve the header information from the header region of the file,
1352	* the xattr region of the file, or some other repository that is
1353	* stored separately from the file itself. The current implementation
1354	* supports retrieving the metadata information from the file contents
1355	* and from the xattr region.
1356	*
1357	* Returns zero if valid headers found and parsed; non-zero otherwise
1358	*/
1359	int ecryptfs_read_metadata(struct dentry *ecryptfs_dentry)
1360	{
1361	int rc;
1362	char *page_virt;
1363	struct inode *ecryptfs_inode = d_inode(dentry: ecryptfs_dentry);
1364	struct ecryptfs_crypt_stat *crypt_stat =
1365	&ecryptfs_inode_to_private(inode: ecryptfs_inode)->crypt_stat;
1366	struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
1367	&ecryptfs_superblock_to_private(
1368	sb: ecryptfs_dentry->d_sb)->mount_crypt_stat;
1369
1370	ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
1371	mount_crypt_stat);
1372	/* Read the first page from the underlying file */
1373	page_virt = kmem_cache_alloc(ecryptfs_header_cache, GFP_USER);
1374	if (!page_virt) {
1375	rc = -ENOMEM;
1376	goto out;
1377	}
1378	rc = ecryptfs_read_lower(data: page_virt, offset: 0, size: crypt_stat->extent_size,
1379	ecryptfs_inode);
1380	if (rc >= 0)
1381	rc = ecryptfs_read_headers_virt(page_virt, crypt_stat,
1382	ecryptfs_dentry,
1383	ECRYPTFS_VALIDATE_HEADER_SIZE);
1384	if (rc) {
1385	/* metadata is not in the file header, so try xattrs */
1386	memset(page_virt, 0, PAGE_SIZE);
1387	rc = ecryptfs_read_xattr_region(page_virt, ecryptfs_inode);
1388	if (rc) {
1389	printk(KERN_DEBUG "Valid eCryptfs headers not found in "
1390	"file header region or xattr region, inode %lu\n",
1391	ecryptfs_inode->i_ino);
1392	rc = -EINVAL;
1393	goto out;
1394	}
1395	rc = ecryptfs_read_headers_virt(page_virt, crypt_stat,
1396	ecryptfs_dentry,
1397	ECRYPTFS_DONT_VALIDATE_HEADER_SIZE);
1398	if (rc) {
1399	printk(KERN_DEBUG "Valid eCryptfs headers not found in "
1400	"file xattr region either, inode %lu\n",
1401	ecryptfs_inode->i_ino);
1402	rc = -EINVAL;
1403	}
1404	if (crypt_stat->mount_crypt_stat->flags
1405	& ECRYPTFS_XATTR_METADATA_ENABLED) {
1406	crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
1407	} else {
1408	printk(KERN_WARNING "Attempt to access file with "
1409	"crypto metadata only in the extended attribute "
1410	"region, but eCryptfs was mounted without "
1411	"xattr support enabled. eCryptfs will not treat "
1412	"this like an encrypted file, inode %lu\n",
1413	ecryptfs_inode->i_ino);
1414	rc = -EINVAL;
1415	}
1416	}
1417	out:
1418	if (page_virt) {
1419	memset(page_virt, 0, PAGE_SIZE);
1420	kmem_cache_free(s: ecryptfs_header_cache, objp: page_virt);
1421	}
1422	return rc;
1423	}
1424
1425	/*
1426	* ecryptfs_encrypt_filename - encrypt filename
1427	*
1428	* CBC-encrypts the filename. We do not want to encrypt the same
1429	* filename with the same key and IV, which may happen with hard
1430	* links, so we prepend random bits to each filename.
1431	*
1432	* Returns zero on success; non-zero otherwise
1433	*/
1434	static int
1435	ecryptfs_encrypt_filename(struct ecryptfs_filename *filename,
1436	struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
1437	{
1438	int rc = 0;
1439
1440	filename->encrypted_filename = NULL;
1441	filename->encrypted_filename_size = 0;
1442	if (mount_crypt_stat && (mount_crypt_stat->flags
1443	& ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK)) {
1444	size_t packet_size;
1445	size_t remaining_bytes;
1446
1447	rc = ecryptfs_write_tag_70_packet(
1448	NULL, NULL,
1449	packet_size: &filename->encrypted_filename_size,
1450	mount_crypt_stat, NULL,
1451	filename_size: filename->filename_size);
1452	if (rc) {
1453	printk(KERN_ERR "%s: Error attempting to get packet "
1454	"size for tag 72; rc = [%d]\n", __func__,
1455	rc);
1456	filename->encrypted_filename_size = 0;
1457	goto out;
1458	}
1459	filename->encrypted_filename =
1460	kmalloc(filename->encrypted_filename_size, GFP_KERNEL);
1461	if (!filename->encrypted_filename) {
1462	rc = -ENOMEM;
1463	goto out;
1464	}
1465	remaining_bytes = filename->encrypted_filename_size;
1466	rc = ecryptfs_write_tag_70_packet(dest: filename->encrypted_filename,
1467	remaining_bytes: &remaining_bytes,
1468	packet_size: &packet_size,
1469	mount_crypt_stat,
1470	filename: filename->filename,
1471	filename_size: filename->filename_size);
1472	if (rc) {
1473	printk(KERN_ERR "%s: Error attempting to generate "
1474	"tag 70 packet; rc = [%d]\n", __func__,
1475	rc);
1476	kfree(objp: filename->encrypted_filename);
1477	filename->encrypted_filename = NULL;
1478	filename->encrypted_filename_size = 0;
1479	goto out;
1480	}
1481	filename->encrypted_filename_size = packet_size;
1482	} else {
1483	printk(KERN_ERR "%s: No support for requested filename "
1484	"encryption method in this release\n", __func__);
1485	rc = -EOPNOTSUPP;
1486	goto out;
1487	}
1488	out:
1489	return rc;
1490	}
1491
1492	static int ecryptfs_copy_filename(char **copied_name, size_t *copied_name_size,
1493	const char *name, size_t name_size)
1494	{
1495	int rc = 0;
1496
1497	(*copied_name) = kmalloc((name_size + 1), GFP_KERNEL);
1498	if (!(*copied_name)) {
1499	rc = -ENOMEM;
1500	goto out;
1501	}
1502	memcpy((void *)(*copied_name), (void *)name, name_size);
1503	(*copied_name)[(name_size)] = '\0'; /* Only for convenience
1504	* in printing out the
1505	* string in debug
1506	* messages */
1507	(*copied_name_size) = name_size;
1508	out:
1509	return rc;
1510	}
1511
1512	/**
1513	* ecryptfs_process_key_cipher - Perform key cipher initialization.
1514	* @key_tfm: Crypto context for key material, set by this function
1515	* @cipher_name: Name of the cipher
1516	* @key_size: Size of the key in bytes
1517	*
1518	* Returns zero on success. Any crypto_tfm structs allocated here
1519	* should be released by other functions, such as on a superblock put
1520	* event, regardless of whether this function succeeds for fails.
1521	*/
1522	static int
1523	ecryptfs_process_key_cipher(struct crypto_skcipher **key_tfm,
1524	char *cipher_name, size_t *key_size)
1525	{
1526	char dummy_key[ECRYPTFS_MAX_KEY_BYTES];
1527	char *full_alg_name = NULL;
1528	int rc;
1529
1530	*key_tfm = NULL;
1531	if (*key_size > ECRYPTFS_MAX_KEY_BYTES) {
1532	rc = -EINVAL;
1533	printk(KERN_ERR "Requested key size is [%zd] bytes; maximum "
1534	"allowable is [%d]\n", *key_size, ECRYPTFS_MAX_KEY_BYTES);
1535	goto out;
1536	}
1537	rc = ecryptfs_crypto_api_algify_cipher_name(algified_name: &full_alg_name, cipher_name,
1538	chaining_modifier: "ecb");
1539	if (rc)
1540	goto out;
1541	*key_tfm = crypto_alloc_skcipher(alg_name: full_alg_name, type: 0, CRYPTO_ALG_ASYNC);
1542	if (IS_ERR(ptr: *key_tfm)) {
1543	rc = PTR_ERR(ptr: *key_tfm);
1544	printk(KERN_ERR "Unable to allocate crypto cipher with name "
1545	"[%s]; rc = [%d]\n", full_alg_name, rc);
1546	goto out;
1547	}
1548	crypto_skcipher_set_flags(tfm: *key_tfm, CRYPTO_TFM_REQ_FORBID_WEAK_KEYS);
1549	if (*key_size == 0)
1550	*key_size = crypto_skcipher_max_keysize(tfm: *key_tfm);
1551	get_random_bytes(buf: dummy_key, len: *key_size);
1552	rc = crypto_skcipher_setkey(tfm: *key_tfm, key: dummy_key, keylen: *key_size);
1553	if (rc) {
1554	printk(KERN_ERR "Error attempting to set key of size [%zd] for "
1555	"cipher [%s]; rc = [%d]\n", *key_size, full_alg_name,
1556	rc);
1557	rc = -EINVAL;
1558	goto out;
1559	}
1560	out:
1561	kfree(objp: full_alg_name);
1562	return rc;
1563	}
1564
1565	struct kmem_cache *ecryptfs_key_tfm_cache;
1566	static struct list_head key_tfm_list;
1567	DEFINE_MUTEX(key_tfm_list_mutex);
1568
1569	int __init ecryptfs_init_crypto(void)
1570	{
1571	INIT_LIST_HEAD(list: &key_tfm_list);
1572	return 0;
1573	}
1574
1575	/**
1576	* ecryptfs_destroy_crypto - free all cached key_tfms on key_tfm_list
1577	*
1578	* Called only at module unload time
1579	*/
1580	int ecryptfs_destroy_crypto(void)
1581	{
1582	struct ecryptfs_key_tfm *key_tfm, *key_tfm_tmp;
1583
1584	mutex_lock(&key_tfm_list_mutex);
1585	list_for_each_entry_safe(key_tfm, key_tfm_tmp, &key_tfm_list,
1586	key_tfm_list) {
1587	list_del(entry: &key_tfm->key_tfm_list);
1588	crypto_free_skcipher(tfm: key_tfm->key_tfm);
1589	kmem_cache_free(s: ecryptfs_key_tfm_cache, objp: key_tfm);
1590	}
1591	mutex_unlock(lock: &key_tfm_list_mutex);
1592	return 0;
1593	}
1594
1595	int
1596	ecryptfs_add_new_key_tfm(struct ecryptfs_key_tfm **key_tfm, char *cipher_name,
1597	size_t key_size)
1598	{
1599	struct ecryptfs_key_tfm *tmp_tfm;
1600	int rc = 0;
1601
1602	BUG_ON(!mutex_is_locked(&key_tfm_list_mutex));
1603
1604	tmp_tfm = kmem_cache_alloc(ecryptfs_key_tfm_cache, GFP_KERNEL);
1605	if (key_tfm)
1606	(*key_tfm) = tmp_tfm;
1607	if (!tmp_tfm) {
1608	rc = -ENOMEM;
1609	goto out;
1610	}
1611	mutex_init(&tmp_tfm->key_tfm_mutex);
1612	strscpy(tmp_tfm->cipher_name, cipher_name);
1613	tmp_tfm->key_size = key_size;
1614	rc = ecryptfs_process_key_cipher(key_tfm: &tmp_tfm->key_tfm,
1615	cipher_name: tmp_tfm->cipher_name,
1616	key_size: &tmp_tfm->key_size);
1617	if (rc) {
1618	printk(KERN_ERR "Error attempting to initialize key TFM "
1619	"cipher with name = [%s]; rc = [%d]\n",
1620	tmp_tfm->cipher_name, rc);
1621	kmem_cache_free(s: ecryptfs_key_tfm_cache, objp: tmp_tfm);
1622	if (key_tfm)
1623	(*key_tfm) = NULL;
1624	goto out;
1625	}
1626	list_add(new: &tmp_tfm->key_tfm_list, head: &key_tfm_list);
1627	out:
1628	return rc;
1629	}
1630
1631	/**
1632	* ecryptfs_tfm_exists - Search for existing tfm for cipher_name.
1633	* @cipher_name: the name of the cipher to search for
1634	* @key_tfm: set to corresponding tfm if found
1635	*
1636	* Searches for cached key_tfm matching @cipher_name
1637	* Must be called with &key_tfm_list_mutex held
1638	* Returns 1 if found, with @key_tfm set
1639	* Returns 0 if not found, with @key_tfm set to NULL
1640	*/
1641	int ecryptfs_tfm_exists(char *cipher_name, struct ecryptfs_key_tfm **key_tfm)
1642	{
1643	struct ecryptfs_key_tfm *tmp_key_tfm;
1644
1645	BUG_ON(!mutex_is_locked(&key_tfm_list_mutex));
1646
1647	list_for_each_entry(tmp_key_tfm, &key_tfm_list, key_tfm_list) {
1648	if (strcmp(tmp_key_tfm->cipher_name, cipher_name) == 0) {
1649	if (key_tfm)
1650	(*key_tfm) = tmp_key_tfm;
1651	return 1;
1652	}
1653	}
1654	if (key_tfm)
1655	(*key_tfm) = NULL;
1656	return 0;
1657	}
1658
1659	/**
1660	* ecryptfs_get_tfm_and_mutex_for_cipher_name
1661	*
1662	* @tfm: set to cached tfm found, or new tfm created
1663	* @tfm_mutex: set to mutex for cached tfm found, or new tfm created
1664	* @cipher_name: the name of the cipher to search for and/or add
1665	*
1666	* Sets pointers to @tfm & @tfm_mutex matching @cipher_name.
1667	* Searches for cached item first, and creates new if not found.
1668	* Returns 0 on success, non-zero if adding new cipher failed
1669	*/
1670	int ecryptfs_get_tfm_and_mutex_for_cipher_name(struct crypto_skcipher **tfm,
1671	struct mutex **tfm_mutex,
1672	char *cipher_name)
1673	{
1674	struct ecryptfs_key_tfm *key_tfm;
1675	int rc = 0;
1676
1677	(*tfm) = NULL;
1678	(*tfm_mutex) = NULL;
1679
1680	mutex_lock(&key_tfm_list_mutex);
1681	if (!ecryptfs_tfm_exists(cipher_name, key_tfm: &key_tfm)) {
1682	rc = ecryptfs_add_new_key_tfm(key_tfm: &key_tfm, cipher_name, key_size: 0);
1683	if (rc) {
1684	printk(KERN_ERR "Error adding new key_tfm to list; "
1685	"rc = [%d]\n", rc);
1686	goto out;
1687	}
1688	}
1689	(*tfm) = key_tfm->key_tfm;
1690	(*tfm_mutex) = &key_tfm->key_tfm_mutex;
1691	out:
1692	mutex_unlock(lock: &key_tfm_list_mutex);
1693	return rc;
1694	}
1695
1696	/* 64 characters forming a 6-bit target field */
1697	static unsigned char *portable_filename_chars = ("-.0123456789ABCD"
1698	"EFGHIJKLMNOPQRST"
1699	"UVWXYZabcdefghij"
1700	"klmnopqrstuvwxyz");
1701
1702	/* We could either offset on every reverse map or just pad some 0x00's
1703	* at the front here */
1704	static const unsigned char filename_rev_map[256] = {
1705	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 7 */
1706	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 15 */
1707	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 23 */
1708	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 31 */
1709	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 39 */
1710	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, /* 47 */
1711	0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, /* 55 */
1712	0x0A, 0x0B, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 63 */
1713	0x00, 0x0C, 0x0D, 0x0E, 0x0F, 0x10, 0x11, 0x12, /* 71 */
1714	0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1A, /* 79 */
1715	0x1B, 0x1C, 0x1D, 0x1E, 0x1F, 0x20, 0x21, 0x22, /* 87 */
1716	0x23, 0x24, 0x25, 0x00, 0x00, 0x00, 0x00, 0x00, /* 95 */
1717	0x00, 0x26, 0x27, 0x28, 0x29, 0x2A, 0x2B, 0x2C, /* 103 */
1718	0x2D, 0x2E, 0x2F, 0x30, 0x31, 0x32, 0x33, 0x34, /* 111 */
1719	0x35, 0x36, 0x37, 0x38, 0x39, 0x3A, 0x3B, 0x3C, /* 119 */
1720	0x3D, 0x3E, 0x3F /* 123 - 255 initialized to 0x00 */
1721	};
1722
1723	/**
1724	* ecryptfs_encode_for_filename
1725	* @dst: Destination location for encoded filename
1726	* @dst_size: Size of the encoded filename in bytes
1727	* @src: Source location for the filename to encode
1728	* @src_size: Size of the source in bytes
1729	*/
1730	static void ecryptfs_encode_for_filename(unsigned char *dst, size_t *dst_size,
1731	unsigned char *src, size_t src_size)
1732	{
1733	size_t num_blocks;
1734	size_t block_num = 0;
1735	size_t dst_offset = 0;
1736	unsigned char last_block[3];
1737
1738	if (src_size == 0) {
1739	(*dst_size) = 0;
1740	goto out;
1741	}
1742	num_blocks = (src_size / 3);
1743	if ((src_size % 3) == 0) {
1744	memcpy(last_block, (&src[src_size - 3]), 3);
1745	} else {
1746	num_blocks++;
1747	last_block[2] = 0x00;
1748	switch (src_size % 3) {
1749	case 1:
1750	last_block[0] = src[src_size - 1];
1751	last_block[1] = 0x00;
1752	break;
1753	case 2:
1754	last_block[0] = src[src_size - 2];
1755	last_block[1] = src[src_size - 1];
1756	}
1757	}
1758	(*dst_size) = (num_blocks * 4);
1759	if (!dst)
1760	goto out;
1761	while (block_num < num_blocks) {
1762	unsigned char *src_block;
1763	unsigned char dst_block[4];
1764
1765	if (block_num == (num_blocks - 1))
1766	src_block = last_block;
1767	else
1768	src_block = &src[block_num * 3];
1769	dst_block[0] = ((src_block[0] >> 2) & 0x3F);
1770	dst_block[1] = (((src_block[0] << 4) & 0x30)
1771	| ((src_block[1] >> 4) & 0x0F));
1772	dst_block[2] = (((src_block[1] << 2) & 0x3C)
1773	| ((src_block[2] >> 6) & 0x03));
1774	dst_block[3] = (src_block[2] & 0x3F);
1775	dst[dst_offset++] = portable_filename_chars[dst_block[0]];
1776	dst[dst_offset++] = portable_filename_chars[dst_block[1]];
1777	dst[dst_offset++] = portable_filename_chars[dst_block[2]];
1778	dst[dst_offset++] = portable_filename_chars[dst_block[3]];
1779	block_num++;
1780	}
1781	out:
1782	return;
1783	}
1784
1785	static size_t ecryptfs_max_decoded_size(size_t encoded_size)
1786	{
1787	/* Not exact; conservatively long. Every block of 4
1788	* encoded characters decodes into a block of 3
1789	* decoded characters. This segment of code provides
1790	* the caller with the maximum amount of allocated
1791	* space that @dst will need to point to in a
1792	* subsequent call. */
1793	return ((encoded_size + 1) * 3) / 4;
1794	}
1795
1796	/**
1797	* ecryptfs_decode_from_filename
1798	* @dst: If NULL, this function only sets @dst_size and returns. If
1799	* non-NULL, this function decodes the encoded octets in @src
1800	* into the memory that @dst points to.
1801	* @dst_size: Set to the size of the decoded string.
1802	* @src: The encoded set of octets to decode.
1803	* @src_size: The size of the encoded set of octets to decode.
1804	*/
1805	static void
1806	ecryptfs_decode_from_filename(unsigned char *dst, size_t *dst_size,
1807	const unsigned char *src, size_t src_size)
1808	{
1809	u8 current_bit_offset = 0;
1810	size_t src_byte_offset = 0;
1811	size_t dst_byte_offset = 0;
1812
1813	if (!dst) {
1814	(*dst_size) = ecryptfs_max_decoded_size(encoded_size: src_size);
1815	goto out;
1816	}
1817	while (src_byte_offset < src_size) {
1818	unsigned char src_byte =
1819	filename_rev_map[(int)src[src_byte_offset]];
1820
1821	switch (current_bit_offset) {
1822	case 0:
1823	dst[dst_byte_offset] = (src_byte << 2);
1824	current_bit_offset = 6;
1825	break;
1826	case 6:
1827	dst[dst_byte_offset++] |= (src_byte >> 4);
1828	dst[dst_byte_offset] = ((src_byte & 0xF)
1829	<< 4);
1830	current_bit_offset = 4;
1831	break;
1832	case 4:
1833	dst[dst_byte_offset++] |= (src_byte >> 2);
1834	dst[dst_byte_offset] = (src_byte << 6);
1835	current_bit_offset = 2;
1836	break;
1837	case 2:
1838	dst[dst_byte_offset++] |= (src_byte);
1839	current_bit_offset = 0;
1840	break;
1841	}
1842	src_byte_offset++;
1843	}
1844	(*dst_size) = dst_byte_offset;
1845	out:
1846	return;
1847	}
1848
1849	/**
1850	* ecryptfs_encrypt_and_encode_filename - converts a plaintext file name to cipher text
1851	* @encoded_name: The encrypted name
1852	* @encoded_name_size: Length of the encrypted name
1853	* @mount_crypt_stat: The crypt_stat struct associated with the file name to encode
1854	* @name: The plaintext name
1855	* @name_size: The length of the plaintext name
1856	*
1857	* Encrypts and encodes a filename into something that constitutes a
1858	* valid filename for a filesystem, with printable characters.
1859	*
1860	* We assume that we have a properly initialized crypto context,
1861	* pointed to by crypt_stat->tfm.
1862	*
1863	* Returns zero on success; non-zero on otherwise
1864	*/
1865	int ecryptfs_encrypt_and_encode_filename(
1866	char **encoded_name,
1867	size_t *encoded_name_size,
1868	struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
1869	const char *name, size_t name_size)
1870	{
1871	size_t encoded_name_no_prefix_size;
1872	int rc = 0;
1873
1874	(*encoded_name) = NULL;
1875	(*encoded_name_size) = 0;
1876	if (mount_crypt_stat && (mount_crypt_stat->flags
1877	& ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)) {
1878	struct ecryptfs_filename *filename;
1879
1880	filename = kzalloc(sizeof(*filename), GFP_KERNEL);
1881	if (!filename) {
1882	rc = -ENOMEM;
1883	goto out;
1884	}
1885	filename->filename = (char *)name;
1886	filename->filename_size = name_size;
1887	rc = ecryptfs_encrypt_filename(filename, mount_crypt_stat);
1888	if (rc) {
1889	printk(KERN_ERR "%s: Error attempting to encrypt "
1890	"filename; rc = [%d]\n", __func__, rc);
1891	kfree(objp: filename);
1892	goto out;
1893	}
1894	ecryptfs_encode_for_filename(
1895	NULL, dst_size: &encoded_name_no_prefix_size,
1896	src: filename->encrypted_filename,
1897	src_size: filename->encrypted_filename_size);
1898	if (mount_crypt_stat
1899	&& (mount_crypt_stat->flags
1900	& ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK))
1901	(*encoded_name_size) =
1902	(ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE
1903	+ encoded_name_no_prefix_size);
1904	else
1905	(*encoded_name_size) =
1906	(ECRYPTFS_FEK_ENCRYPTED_FILENAME_PREFIX_SIZE
1907	+ encoded_name_no_prefix_size);
1908	(*encoded_name) = kmalloc((*encoded_name_size) + 1, GFP_KERNEL);
1909	if (!(*encoded_name)) {
1910	rc = -ENOMEM;
1911	kfree(objp: filename->encrypted_filename);
1912	kfree(objp: filename);
1913	goto out;
1914	}
1915	if (mount_crypt_stat
1916	&& (mount_crypt_stat->flags
1917	& ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK)) {
1918	memcpy((*encoded_name),
1919	ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX,
1920	ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE);
1921	ecryptfs_encode_for_filename(
1922	dst: ((*encoded_name)
1923	+ ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE),
1924	dst_size: &encoded_name_no_prefix_size,
1925	src: filename->encrypted_filename,
1926	src_size: filename->encrypted_filename_size);
1927	(*encoded_name_size) =
1928	(ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE
1929	+ encoded_name_no_prefix_size);
1930	(*encoded_name)[(*encoded_name_size)] = '\0';
1931	} else {
1932	rc = -EOPNOTSUPP;
1933	}
1934	if (rc) {
1935	printk(KERN_ERR "%s: Error attempting to encode "
1936	"encrypted filename; rc = [%d]\n", __func__,
1937	rc);
1938	kfree(objp: (*encoded_name));
1939	(*encoded_name) = NULL;
1940	(*encoded_name_size) = 0;
1941	}
1942	kfree(objp: filename->encrypted_filename);
1943	kfree(objp: filename);
1944	} else {
1945	rc = ecryptfs_copy_filename(copied_name: encoded_name,
1946	copied_name_size: encoded_name_size,
1947	name, name_size);
1948	}
1949	out:
1950	return rc;
1951	}
1952
1953	/**
1954	* ecryptfs_decode_and_decrypt_filename - converts the encoded cipher text name to decoded plaintext
1955	* @plaintext_name: The plaintext name
1956	* @plaintext_name_size: The plaintext name size
1957	* @sb: Ecryptfs's super_block
1958	* @name: The filename in cipher text
1959	* @name_size: The cipher text name size
1960	*
1961	* Decrypts and decodes the filename.
1962	*
1963	* Returns zero on error; non-zero otherwise
1964	*/
1965	int ecryptfs_decode_and_decrypt_filename(char **plaintext_name,
1966	size_t *plaintext_name_size,
1967	struct super_block *sb,
1968	const char *name, size_t name_size)
1969	{
1970	struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
1971	&ecryptfs_superblock_to_private(sb)->mount_crypt_stat;
1972	char *decoded_name;
1973	size_t decoded_name_size;
1974	size_t packet_size;
1975	int rc = 0;
1976
1977	if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) &&
1978	!(mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)) {
1979	if (is_dot_dotdot(name, len: name_size)) {
1980	rc = ecryptfs_copy_filename(copied_name: plaintext_name,
1981	copied_name_size: plaintext_name_size,
1982	name, name_size);
1983	goto out;
1984	}
1985
1986	if (name_size <= ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE ||
1987	strncmp(name, ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX,
1988	ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE)) {
1989	rc = -EINVAL;
1990	goto out;
1991	}
1992
1993	name += ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE;
1994	name_size -= ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE;
1995	ecryptfs_decode_from_filename(NULL, dst_size: &decoded_name_size,
1996	src: name, src_size: name_size);
1997	decoded_name = kmalloc(decoded_name_size, GFP_KERNEL);
1998	if (!decoded_name) {
1999	rc = -ENOMEM;
2000	goto out;
2001	}
2002	ecryptfs_decode_from_filename(dst: decoded_name, dst_size: &decoded_name_size,
2003	src: name, src_size: name_size);
2004	rc = ecryptfs_parse_tag_70_packet(filename: plaintext_name,
2005	filename_size: plaintext_name_size,
2006	packet_size: &packet_size,
2007	mount_crypt_stat,
2008	data: decoded_name,
2009	max_packet_size: decoded_name_size);
2010	if (rc) {
2011	ecryptfs_printk(KERN_DEBUG,
2012	"%s: Could not parse tag 70 packet from filename\n",
2013	__func__);
2014	goto out_free;
2015	}
2016	} else {
2017	rc = ecryptfs_copy_filename(copied_name: plaintext_name,
2018	copied_name_size: plaintext_name_size,
2019	name, name_size);
2020	goto out;
2021	}
2022	out_free:
2023	kfree(objp: decoded_name);
2024	out:
2025	return rc;
2026	}
2027
2028	#define ENC_NAME_MAX_BLOCKLEN_8_OR_16 143
2029
2030	int ecryptfs_set_f_namelen(long *namelen, long lower_namelen,
2031	struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
2032	{
2033	struct crypto_skcipher *tfm;
2034	struct mutex *tfm_mutex;
2035	size_t cipher_blocksize;
2036	int rc;
2037
2038	if (!(mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)) {
2039	(*namelen) = lower_namelen;
2040	return 0;
2041	}
2042
2043	rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(tfm: &tfm, tfm_mutex: &tfm_mutex,
2044	cipher_name: mount_crypt_stat->global_default_fn_cipher_name);
2045	if (unlikely(rc)) {
2046	(*namelen) = 0;
2047	return rc;
2048	}
2049
2050	mutex_lock(tfm_mutex);
2051	cipher_blocksize = crypto_skcipher_blocksize(tfm);
2052	mutex_unlock(lock: tfm_mutex);
2053
2054	/* Return an exact amount for the common cases */
2055	if (lower_namelen == NAME_MAX
2056	&& (cipher_blocksize == 8 || cipher_blocksize == 16)) {
2057	(*namelen) = ENC_NAME_MAX_BLOCKLEN_8_OR_16;
2058	return 0;
2059	}
2060
2061	/* Return a safe estimate for the uncommon cases */
2062	(*namelen) = lower_namelen;
2063	(*namelen) -= ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE;
2064	/* Since this is the max decoded size, subtract 1 "decoded block" len */
2065	(*namelen) = ecryptfs_max_decoded_size(encoded_size: *namelen) - 3;
2066	(*namelen) -= ECRYPTFS_TAG_70_MAX_METADATA_SIZE;
2067	(*namelen) -= ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES;
2068	/* Worst case is that the filename is padded nearly a full block size */
2069	(*namelen) -= cipher_blocksize - 1;
2070
2071	if ((*namelen) < 0)
2072	(*namelen) = 0;
2073
2074	return 0;
2075	}
2076