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 <asm/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(size: 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(tfm: 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 page *page)
332	{
333	return ecryptfs_lower_header_size(crypt_stat) +
334	((loff_t)page->index << PAGE_SHIFT);
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	* @extent_offset: Page extent offset for use in generating IV
344	* @op: ENCRYPT or DECRYPT to indicate the desired operation
345	*
346	* Encrypts or decrypts one extent of data.
347	*
348	* Return zero on success; non-zero otherwise
349	*/
350	static int crypt_extent(struct ecryptfs_crypt_stat *crypt_stat,
351	struct page *dst_page,
352	struct page *src_page,
353	unsigned long extent_offset, int op)
354	{
355	pgoff_t page_index = op == ENCRYPT ? src_page->index : dst_page->index;
356	loff_t extent_base;
357	char extent_iv[ECRYPTFS_MAX_IV_BYTES];
358	struct scatterlist src_sg, dst_sg;
359	size_t extent_size = crypt_stat->extent_size;
360	int rc;
361
362	extent_base = (((loff_t)page_index) * (PAGE_SIZE / extent_size));
363	rc = ecryptfs_derive_iv(iv: extent_iv, crypt_stat,
364	offset: (extent_base + extent_offset));
365	if (rc) {
366	ecryptfs_printk(KERN_ERR, "Error attempting to derive IV for "
367	"extent [0x%.16llx]; rc = [%d]\n",
368	(unsigned long long)(extent_base + extent_offset), rc);
369	goto out;
370	}
371
372	sg_init_table(&src_sg, 1);
373	sg_init_table(&dst_sg, 1);
374
375	sg_set_page(sg: &src_sg, page: src_page, len: extent_size,
376	offset: extent_offset * extent_size);
377	sg_set_page(sg: &dst_sg, page: dst_page, len: extent_size,
378	offset: extent_offset * extent_size);
379
380	rc = crypt_scatterlist(crypt_stat, dst_sg: &dst_sg, src_sg: &src_sg, size: extent_size,
381	iv: extent_iv, op);
382	if (rc < 0) {
383	printk(KERN_ERR "%s: Error attempting to crypt page with "
384	"page_index = [%ld], extent_offset = [%ld]; "
385	"rc = [%d]\n", __func__, page_index, extent_offset, rc);
386	goto out;
387	}
388	rc = 0;
389	out:
390	return rc;
391	}
392
393	/**
394	* ecryptfs_encrypt_page
395	* @page: Page mapped from the eCryptfs inode for the file; contains
396	* decrypted content that needs to be encrypted (to a temporary
397	* page; not in place) and written out to the lower file
398	*
399	* Encrypt an eCryptfs page. This is done on a per-extent basis. Note
400	* that eCryptfs pages may straddle the lower pages -- for instance,
401	* if the file was created on a machine with an 8K page size
402	* (resulting in an 8K header), and then the file is copied onto a
403	* host with a 32K page size, then when reading page 0 of the eCryptfs
404	* file, 24K of page 0 of the lower file will be read and decrypted,
405	* and then 8K of page 1 of the lower file will be read and decrypted.
406	*
407	* Returns zero on success; negative on error
408	*/
409	int ecryptfs_encrypt_page(struct page *page)
410	{
411	struct inode *ecryptfs_inode;
412	struct ecryptfs_crypt_stat *crypt_stat;
413	char *enc_extent_virt;
414	struct page *enc_extent_page = NULL;
415	loff_t extent_offset;
416	loff_t lower_offset;
417	int rc = 0;
418
419	ecryptfs_inode = page->mapping->host;
420	crypt_stat =
421	&(ecryptfs_inode_to_private(inode: ecryptfs_inode)->crypt_stat);
422	BUG_ON(!(crypt_stat->flags & ECRYPTFS_ENCRYPTED));
423	enc_extent_page = alloc_page(GFP_USER);
424	if (!enc_extent_page) {
425	rc = -ENOMEM;
426	ecryptfs_printk(KERN_ERR, "Error allocating memory for "
427	"encrypted extent\n");
428	goto out;
429	}
430
431	for (extent_offset = 0;
432	extent_offset < (PAGE_SIZE / crypt_stat->extent_size);
433	extent_offset++) {
434	rc = crypt_extent(crypt_stat, dst_page: enc_extent_page, src_page: page,
435	extent_offset, ENCRYPT);
436	if (rc) {
437	printk(KERN_ERR "%s: Error encrypting extent; "
438	"rc = [%d]\n", __func__, rc);
439	goto out;
440	}
441	}
442
443	lower_offset = lower_offset_for_page(crypt_stat, page);
444	enc_extent_virt = kmap_local_page(page: enc_extent_page);
445	rc = ecryptfs_write_lower(ecryptfs_inode, data: enc_extent_virt, offset: lower_offset,
446	PAGE_SIZE);
447	kunmap_local(enc_extent_virt);
448	if (rc < 0) {
449	ecryptfs_printk(KERN_ERR,
450	"Error attempting to write lower page; rc = [%d]\n",
451	rc);
452	goto out;
453	}
454	rc = 0;
455	out:
456	if (enc_extent_page) {
457	__free_page(enc_extent_page);
458	}
459	return rc;
460	}
461
462	/**
463	* ecryptfs_decrypt_page
464	* @page: Page mapped from the eCryptfs inode for the file; data read
465	* and decrypted from the lower file will be written into this
466	* page
467	*
468	* Decrypt an eCryptfs page. This is done on a per-extent basis. Note
469	* that eCryptfs pages may straddle the lower pages -- for instance,
470	* if the file was created on a machine with an 8K page size
471	* (resulting in an 8K header), and then the file is copied onto a
472	* host with a 32K page size, then when reading page 0 of the eCryptfs
473	* file, 24K of page 0 of the lower file will be read and decrypted,
474	* and then 8K of page 1 of the lower file will be read and decrypted.
475	*
476	* Returns zero on success; negative on error
477	*/
478	int ecryptfs_decrypt_page(struct page *page)
479	{
480	struct inode *ecryptfs_inode;
481	struct ecryptfs_crypt_stat *crypt_stat;
482	char *page_virt;
483	unsigned long extent_offset;
484	loff_t lower_offset;
485	int rc = 0;
486
487	ecryptfs_inode = page->mapping->host;
488	crypt_stat =
489	&(ecryptfs_inode_to_private(inode: ecryptfs_inode)->crypt_stat);
490	BUG_ON(!(crypt_stat->flags & ECRYPTFS_ENCRYPTED));
491
492	lower_offset = lower_offset_for_page(crypt_stat, page);
493	page_virt = kmap_local_page(page);
494	rc = ecryptfs_read_lower(data: page_virt, offset: lower_offset, PAGE_SIZE,
495	ecryptfs_inode);
496	kunmap_local(page_virt);
497	if (rc < 0) {
498	ecryptfs_printk(KERN_ERR,
499	"Error attempting to read lower page; rc = [%d]\n",
500	rc);
501	goto out;
502	}
503
504	for (extent_offset = 0;
505	extent_offset < (PAGE_SIZE / crypt_stat->extent_size);
506	extent_offset++) {
507	rc = crypt_extent(crypt_stat, dst_page: page, src_page: page,
508	extent_offset, DECRYPT);
509	if (rc) {
510	printk(KERN_ERR "%s: Error decrypting extent; "
511	"rc = [%d]\n", __func__, rc);
512	goto out;
513	}
514	}
515	out:
516	return rc;
517	}
518
519	#define ECRYPTFS_MAX_SCATTERLIST_LEN 4
520
521	/**
522	* ecryptfs_init_crypt_ctx
523	* @crypt_stat: Uninitialized crypt stats structure
524	*
525	* Initialize the crypto context.
526	*
527	* TODO: Performance: Keep a cache of initialized cipher contexts;
528	* only init if needed
529	*/
530	int ecryptfs_init_crypt_ctx(struct ecryptfs_crypt_stat *crypt_stat)
531	{
532	char *full_alg_name;
533	int rc = -EINVAL;
534
535	ecryptfs_printk(KERN_DEBUG,
536	"Initializing cipher [%s]; strlen = [%d]; "
537	"key_size_bits = [%zd]\n",
538	crypt_stat->cipher, (int)strlen(crypt_stat->cipher),
539	crypt_stat->key_size << 3);
540	mutex_lock(&crypt_stat->cs_tfm_mutex);
541	if (crypt_stat->tfm) {
542	rc = 0;
543	goto out_unlock;
544	}
545	rc = ecryptfs_crypto_api_algify_cipher_name(algified_name: &full_alg_name,
546	cipher_name: crypt_stat->cipher, chaining_modifier: "cbc");
547	if (rc)
548	goto out_unlock;
549	crypt_stat->tfm = crypto_alloc_skcipher(alg_name: full_alg_name, type: 0, mask: 0);
550	if (IS_ERR(ptr: crypt_stat->tfm)) {
551	rc = PTR_ERR(ptr: crypt_stat->tfm);
552	crypt_stat->tfm = NULL;
553	ecryptfs_printk(KERN_ERR, "cryptfs: init_crypt_ctx(): "
554	"Error initializing cipher [%s]\n",
555	full_alg_name);
556	goto out_free;
557	}
558	crypto_skcipher_set_flags(tfm: crypt_stat->tfm,
559	CRYPTO_TFM_REQ_FORBID_WEAK_KEYS);
560	rc = 0;
561	out_free:
562	kfree(objp: full_alg_name);
563	out_unlock:
564	mutex_unlock(lock: &crypt_stat->cs_tfm_mutex);
565	return rc;
566	}
567
568	static void set_extent_mask_and_shift(struct ecryptfs_crypt_stat *crypt_stat)
569	{
570	int extent_size_tmp;
571
572	crypt_stat->extent_mask = 0xFFFFFFFF;
573	crypt_stat->extent_shift = 0;
574	if (crypt_stat->extent_size == 0)
575	return;
576	extent_size_tmp = crypt_stat->extent_size;
577	while ((extent_size_tmp & 0x01) == 0) {
578	extent_size_tmp >>= 1;
579	crypt_stat->extent_mask <<= 1;
580	crypt_stat->extent_shift++;
581	}
582	}
583
584	void ecryptfs_set_default_sizes(struct ecryptfs_crypt_stat *crypt_stat)
585	{
586	/* Default values; may be overwritten as we are parsing the
587	* packets. */
588	crypt_stat->extent_size = ECRYPTFS_DEFAULT_EXTENT_SIZE;
589	set_extent_mask_and_shift(crypt_stat);
590	crypt_stat->iv_bytes = ECRYPTFS_DEFAULT_IV_BYTES;
591	if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
592	crypt_stat->metadata_size = ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
593	else {
594	if (PAGE_SIZE <= ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE)
595	crypt_stat->metadata_size =
596	ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
597	else
598	crypt_stat->metadata_size = PAGE_SIZE;
599	}
600	}
601
602	/*
603	* ecryptfs_compute_root_iv
604	*
605	* On error, sets the root IV to all 0's.
606	*/
607	int ecryptfs_compute_root_iv(struct ecryptfs_crypt_stat *crypt_stat)
608	{
609	int rc = 0;
610	char dst[MD5_DIGEST_SIZE];
611
612	BUG_ON(crypt_stat->iv_bytes > MD5_DIGEST_SIZE);
613	BUG_ON(crypt_stat->iv_bytes <= 0);
614	if (!(crypt_stat->flags & ECRYPTFS_KEY_VALID)) {
615	rc = -EINVAL;
616	ecryptfs_printk(KERN_WARNING, "Session key not valid; "
617	"cannot generate root IV\n");
618	goto out;
619	}
620	rc = ecryptfs_calculate_md5(dst, crypt_stat, src: crypt_stat->key,
621	len: crypt_stat->key_size);
622	if (rc) {
623	ecryptfs_printk(KERN_WARNING, "Error attempting to compute "
624	"MD5 while generating root IV\n");
625	goto out;
626	}
627	memcpy(crypt_stat->root_iv, dst, crypt_stat->iv_bytes);
628	out:
629	if (rc) {
630	memset(crypt_stat->root_iv, 0, crypt_stat->iv_bytes);
631	crypt_stat->flags |= ECRYPTFS_SECURITY_WARNING;
632	}
633	return rc;
634	}
635
636	static void ecryptfs_generate_new_key(struct ecryptfs_crypt_stat *crypt_stat)
637	{
638	get_random_bytes(buf: crypt_stat->key, len: crypt_stat->key_size);
639	crypt_stat->flags |= ECRYPTFS_KEY_VALID;
640	ecryptfs_compute_root_iv(crypt_stat);
641	if (unlikely(ecryptfs_verbosity > 0)) {
642	ecryptfs_printk(KERN_DEBUG, "Generated new session key:\n");
643	ecryptfs_dump_hex(data: crypt_stat->key,
644	bytes: crypt_stat->key_size);
645	}
646	}
647
648	/**
649	* ecryptfs_copy_mount_wide_flags_to_inode_flags
650	* @crypt_stat: The inode's cryptographic context
651	* @mount_crypt_stat: The mount point's cryptographic context
652	*
653	* This function propagates the mount-wide flags to individual inode
654	* flags.
655	*/
656	static void ecryptfs_copy_mount_wide_flags_to_inode_flags(
657	struct ecryptfs_crypt_stat *crypt_stat,
658	struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
659	{
660	if (mount_crypt_stat->flags & ECRYPTFS_XATTR_METADATA_ENABLED)
661	crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
662	if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
663	crypt_stat->flags |= ECRYPTFS_VIEW_AS_ENCRYPTED;
664	if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) {
665	crypt_stat->flags |= ECRYPTFS_ENCRYPT_FILENAMES;
666	if (mount_crypt_stat->flags
667	& ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK)
668	crypt_stat->flags |= ECRYPTFS_ENCFN_USE_MOUNT_FNEK;
669	else if (mount_crypt_stat->flags
670	& ECRYPTFS_GLOBAL_ENCFN_USE_FEK)
671	crypt_stat->flags |= ECRYPTFS_ENCFN_USE_FEK;
672	}
673	}
674
675	static int ecryptfs_copy_mount_wide_sigs_to_inode_sigs(
676	struct ecryptfs_crypt_stat *crypt_stat,
677	struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
678	{
679	struct ecryptfs_global_auth_tok *global_auth_tok;
680	int rc = 0;
681
682	mutex_lock(&crypt_stat->keysig_list_mutex);
683	mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
684
685	list_for_each_entry(global_auth_tok,
686	&mount_crypt_stat->global_auth_tok_list,
687	mount_crypt_stat_list) {
688	if (global_auth_tok->flags & ECRYPTFS_AUTH_TOK_FNEK)
689	continue;
690	rc = ecryptfs_add_keysig(crypt_stat, sig: global_auth_tok->sig);
691	if (rc) {
692	printk(KERN_ERR "Error adding keysig; rc = [%d]\n", rc);
693	goto out;
694	}
695	}
696
697	out:
698	mutex_unlock(lock: &mount_crypt_stat->global_auth_tok_list_mutex);
699	mutex_unlock(lock: &crypt_stat->keysig_list_mutex);
700	return rc;
701	}
702
703	/**
704	* ecryptfs_set_default_crypt_stat_vals
705	* @crypt_stat: The inode's cryptographic context
706	* @mount_crypt_stat: The mount point's cryptographic context
707	*
708	* Default values in the event that policy does not override them.
709	*/
710	static void ecryptfs_set_default_crypt_stat_vals(
711	struct ecryptfs_crypt_stat *crypt_stat,
712	struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
713	{
714	ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
715	mount_crypt_stat);
716	ecryptfs_set_default_sizes(crypt_stat);
717	strcpy(p: crypt_stat->cipher, ECRYPTFS_DEFAULT_CIPHER);
718	crypt_stat->key_size = ECRYPTFS_DEFAULT_KEY_BYTES;
719	crypt_stat->flags &= ~(ECRYPTFS_KEY_VALID);
720	crypt_stat->file_version = ECRYPTFS_FILE_VERSION;
721	crypt_stat->mount_crypt_stat = mount_crypt_stat;
722	}
723
724	/**
725	* ecryptfs_new_file_context
726	* @ecryptfs_inode: The eCryptfs inode
727	*
728	* If the crypto context for the file has not yet been established,
729	* this is where we do that. Establishing a new crypto context
730	* involves the following decisions:
731	* - What cipher to use?
732	* - What set of authentication tokens to use?
733	* Here we just worry about getting enough information into the
734	* authentication tokens so that we know that they are available.
735	* We associate the available authentication tokens with the new file
736	* via the set of signatures in the crypt_stat struct. Later, when
737	* the headers are actually written out, we may again defer to
738	* userspace to perform the encryption of the session key; for the
739	* foreseeable future, this will be the case with public key packets.
740	*
741	* Returns zero on success; non-zero otherwise
742	*/
743	int ecryptfs_new_file_context(struct inode *ecryptfs_inode)
744	{
745	struct ecryptfs_crypt_stat *crypt_stat =
746	&ecryptfs_inode_to_private(inode: ecryptfs_inode)->crypt_stat;
747	struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
748	&ecryptfs_superblock_to_private(
749	sb: ecryptfs_inode->i_sb)->mount_crypt_stat;
750	int cipher_name_len;
751	int rc = 0;
752
753	ecryptfs_set_default_crypt_stat_vals(crypt_stat, mount_crypt_stat);
754	crypt_stat->flags |= (ECRYPTFS_ENCRYPTED | ECRYPTFS_KEY_VALID);
755	ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
756	mount_crypt_stat);
757	rc = ecryptfs_copy_mount_wide_sigs_to_inode_sigs(crypt_stat,
758	mount_crypt_stat);
759	if (rc) {
760	printk(KERN_ERR "Error attempting to copy mount-wide key sigs "
761	"to the inode key sigs; rc = [%d]\n", rc);
762	goto out;
763	}
764	cipher_name_len =
765	strlen(mount_crypt_stat->global_default_cipher_name);
766	memcpy(crypt_stat->cipher,
767	mount_crypt_stat->global_default_cipher_name,
768	cipher_name_len);
769	crypt_stat->cipher[cipher_name_len] = '\0';
770	crypt_stat->key_size =
771	mount_crypt_stat->global_default_cipher_key_size;
772	ecryptfs_generate_new_key(crypt_stat);
773	rc = ecryptfs_init_crypt_ctx(crypt_stat);
774	if (rc)
775	ecryptfs_printk(KERN_ERR, "Error initializing cryptographic "
776	"context for cipher [%s]: rc = [%d]\n",
777	crypt_stat->cipher, rc);
778	out:
779	return rc;
780	}
781
782	/**
783	* ecryptfs_validate_marker - check for the ecryptfs marker
784	* @data: The data block in which to check
785	*
786	* Returns zero if marker found; -EINVAL if not found
787	*/
788	static int ecryptfs_validate_marker(char *data)
789	{
790	u32 m_1, m_2;
791
792	m_1 = get_unaligned_be32(p: data);
793	m_2 = get_unaligned_be32(p: data + 4);
794	if ((m_1 ^ MAGIC_ECRYPTFS_MARKER) == m_2)
795	return 0;
796	ecryptfs_printk(KERN_DEBUG, "m_1 = [0x%.8x]; m_2 = [0x%.8x]; "
797	"MAGIC_ECRYPTFS_MARKER = [0x%.8x]\n", m_1, m_2,
798	MAGIC_ECRYPTFS_MARKER);
799	ecryptfs_printk(KERN_DEBUG, "(m_1 ^ MAGIC_ECRYPTFS_MARKER) = "
800	"[0x%.8x]\n", (m_1 ^ MAGIC_ECRYPTFS_MARKER));
801	return -EINVAL;
802	}
803
804	struct ecryptfs_flag_map_elem {
805	u32 file_flag;
806	u32 local_flag;
807	};
808
809	/* Add support for additional flags by adding elements here. */
810	static struct ecryptfs_flag_map_elem ecryptfs_flag_map[] = {
811	{0x00000001, ECRYPTFS_ENABLE_HMAC},
812	{0x00000002, ECRYPTFS_ENCRYPTED},
813	{0x00000004, ECRYPTFS_METADATA_IN_XATTR},
814	{0x00000008, ECRYPTFS_ENCRYPT_FILENAMES}
815	};
816
817	/**
818	* ecryptfs_process_flags
819	* @crypt_stat: The cryptographic context
820	* @page_virt: Source data to be parsed
821	* @bytes_read: Updated with the number of bytes read
822	*/
823	static void ecryptfs_process_flags(struct ecryptfs_crypt_stat *crypt_stat,
824	char *page_virt, int *bytes_read)
825	{
826	int i;
827	u32 flags;
828
829	flags = get_unaligned_be32(p: page_virt);
830	for (i = 0; i < ARRAY_SIZE(ecryptfs_flag_map); i++)
831	if (flags & ecryptfs_flag_map[i].file_flag) {
832	crypt_stat->flags |= ecryptfs_flag_map[i].local_flag;
833	} else
834	crypt_stat->flags &= ~(ecryptfs_flag_map[i].local_flag);
835	/* Version is in top 8 bits of the 32-bit flag vector */
836	crypt_stat->file_version = ((flags >> 24) & 0xFF);
837	(*bytes_read) = 4;
838	}
839
840	/**
841	* write_ecryptfs_marker
842	* @page_virt: The pointer to in a page to begin writing the marker
843	* @written: Number of bytes written
844	*
845	* Marker = 0x3c81b7f5
846	*/
847	static void write_ecryptfs_marker(char *page_virt, size_t *written)
848	{
849	u32 m_1, m_2;
850
851	get_random_bytes(buf: &m_1, len: (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2));
852	m_2 = (m_1 ^ MAGIC_ECRYPTFS_MARKER);
853	put_unaligned_be32(val: m_1, p: page_virt);
854	page_virt += (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2);
855	put_unaligned_be32(val: m_2, p: page_virt);
856	(*written) = MAGIC_ECRYPTFS_MARKER_SIZE_BYTES;
857	}
858
859	void ecryptfs_write_crypt_stat_flags(char *page_virt,
860	struct ecryptfs_crypt_stat *crypt_stat,
861	size_t *written)
862	{
863	u32 flags = 0;
864	int i;
865
866	for (i = 0; i < ARRAY_SIZE(ecryptfs_flag_map); i++)
867	if (crypt_stat->flags & ecryptfs_flag_map[i].local_flag)
868	flags |= ecryptfs_flag_map[i].file_flag;
869	/* Version is in top 8 bits of the 32-bit flag vector */
870	flags |= ((((u8)crypt_stat->file_version) << 24) & 0xFF000000);
871	put_unaligned_be32(val: flags, p: page_virt);
872	(*written) = 4;
873	}
874
875	struct ecryptfs_cipher_code_str_map_elem {
876	char cipher_str[16];
877	u8 cipher_code;
878	};
879
880	/* Add support for additional ciphers by adding elements here. The
881	* cipher_code is whatever OpenPGP applications use to identify the
882	* ciphers. List in order of probability. */
883	static struct ecryptfs_cipher_code_str_map_elem
884	ecryptfs_cipher_code_str_map[] = {
885	{"aes",RFC2440_CIPHER_AES_128 },
886	{"blowfish", RFC2440_CIPHER_BLOWFISH},
887	{"des3_ede", RFC2440_CIPHER_DES3_EDE},
888	{"cast5", RFC2440_CIPHER_CAST_5},
889	{"twofish", RFC2440_CIPHER_TWOFISH},
890	{"cast6", RFC2440_CIPHER_CAST_6},
891	{"aes", RFC2440_CIPHER_AES_192},
892	{"aes", RFC2440_CIPHER_AES_256}
893	};
894
895	/**
896	* ecryptfs_code_for_cipher_string
897	* @cipher_name: The string alias for the cipher
898	* @key_bytes: Length of key in bytes; used for AES code selection
899	*
900	* Returns zero on no match, or the cipher code on match
901	*/
902	u8 ecryptfs_code_for_cipher_string(char *cipher_name, size_t key_bytes)
903	{
904	int i;
905	u8 code = 0;
906	struct ecryptfs_cipher_code_str_map_elem *map =
907	ecryptfs_cipher_code_str_map;
908
909	if (strcmp(cipher_name, "aes") == 0) {
910	switch (key_bytes) {
911	case 16:
912	code = RFC2440_CIPHER_AES_128;
913	break;
914	case 24:
915	code = RFC2440_CIPHER_AES_192;
916	break;
917	case 32:
918	code = RFC2440_CIPHER_AES_256;
919	}
920	} else {
921	for (i = 0; i < ARRAY_SIZE(ecryptfs_cipher_code_str_map); i++)
922	if (strcmp(cipher_name, map[i].cipher_str) == 0) {
923	code = map[i].cipher_code;
924	break;
925	}
926	}
927	return code;
928	}
929
930	/**
931	* ecryptfs_cipher_code_to_string
932	* @str: Destination to write out the cipher name
933	* @cipher_code: The code to convert to cipher name string
934	*
935	* Returns zero on success
936	*/
937	int ecryptfs_cipher_code_to_string(char *str, u8 cipher_code)
938	{
939	int rc = 0;
940	int i;
941
942	str[0] = '\0';
943	for (i = 0; i < ARRAY_SIZE(ecryptfs_cipher_code_str_map); i++)
944	if (cipher_code == ecryptfs_cipher_code_str_map[i].cipher_code)
945	strcpy(p: str, q: ecryptfs_cipher_code_str_map[i].cipher_str);
946	if (str[0] == '\0') {
947	ecryptfs_printk(KERN_WARNING, "Cipher code not recognized: "
948	"[%d]\n", cipher_code);
949	rc = -EINVAL;
950	}
951	return rc;
952	}
953
954	int ecryptfs_read_and_validate_header_region(struct inode *inode)
955	{
956	u8 file_size[ECRYPTFS_SIZE_AND_MARKER_BYTES];
957	u8 *marker = file_size + ECRYPTFS_FILE_SIZE_BYTES;
958	int rc;
959
960	rc = ecryptfs_read_lower(data: file_size, offset: 0, ECRYPTFS_SIZE_AND_MARKER_BYTES,
961	ecryptfs_inode: inode);
962	if (rc < 0)
963	return rc;
964	else if (rc < ECRYPTFS_SIZE_AND_MARKER_BYTES)
965	return -EINVAL;
966	rc = ecryptfs_validate_marker(data: marker);
967	if (!rc)
968	ecryptfs_i_size_init(page_virt: file_size, inode);
969	return rc;
970	}
971
972	void
973	ecryptfs_write_header_metadata(char *virt,
974	struct ecryptfs_crypt_stat *crypt_stat,
975	size_t *written)
976	{
977	u32 header_extent_size;
978	u16 num_header_extents_at_front;
979
980	header_extent_size = (u32)crypt_stat->extent_size;
981	num_header_extents_at_front =
982	(u16)(crypt_stat->metadata_size / crypt_stat->extent_size);
983	put_unaligned_be32(val: header_extent_size, p: virt);
984	virt += 4;
985	put_unaligned_be16(val: num_header_extents_at_front, p: virt);
986	(*written) = 6;
987	}
988
989	struct kmem_cache *ecryptfs_header_cache;
990
991	/**
992	* ecryptfs_write_headers_virt
993	* @page_virt: The virtual address to write the headers to
994	* @max: The size of memory allocated at page_virt
995	* @size: Set to the number of bytes written by this function
996	* @crypt_stat: The cryptographic context
997	* @ecryptfs_dentry: The eCryptfs dentry
998	*
999	* Format version: 1
1000	*
1001	* Header Extent:
1002	* Octets 0-7: Unencrypted file size (big-endian)
1003	* Octets 8-15: eCryptfs special marker
1004	* Octets 16-19: Flags
1005	* Octet 16: File format version number (between 0 and 255)
1006	* Octets 17-18: Reserved
1007	* Octet 19: Bit 1 (lsb): Reserved
1008	* Bit 2: Encrypted?
1009	* Bits 3-8: Reserved
1010	* Octets 20-23: Header extent size (big-endian)
1011	* Octets 24-25: Number of header extents at front of file
1012	* (big-endian)
1013	* Octet 26: Begin RFC 2440 authentication token packet set
1014	* Data Extent 0:
1015	* Lower data (CBC encrypted)
1016	* Data Extent 1:
1017	* Lower data (CBC encrypted)
1018	* ...
1019	*
1020	* Returns zero on success
1021	*/
1022	static int ecryptfs_write_headers_virt(char *page_virt, size_t max,
1023	size_t *size,
1024	struct ecryptfs_crypt_stat *crypt_stat,
1025	struct dentry *ecryptfs_dentry)
1026	{
1027	int rc;
1028	size_t written;
1029	size_t offset;
1030
1031	offset = ECRYPTFS_FILE_SIZE_BYTES;
1032	write_ecryptfs_marker(page_virt: (page_virt + offset), written: &written);
1033	offset += written;
1034	ecryptfs_write_crypt_stat_flags(page_virt: (page_virt + offset), crypt_stat,
1035	written: &written);
1036	offset += written;
1037	ecryptfs_write_header_metadata(virt: (page_virt + offset), crypt_stat,
1038	written: &written);
1039	offset += written;
1040	rc = ecryptfs_generate_key_packet_set(dest_base: (page_virt + offset), crypt_stat,
1041	ecryptfs_dentry, len: &written,
1042	max: max - offset);
1043	if (rc)
1044	ecryptfs_printk(KERN_WARNING, "Error generating key packet "
1045	"set; rc = [%d]\n", rc);
1046	if (size) {
1047	offset += written;
1048	*size = offset;
1049	}
1050	return rc;
1051	}
1052
1053	static int
1054	ecryptfs_write_metadata_to_contents(struct inode *ecryptfs_inode,
1055	char *virt, size_t virt_len)
1056	{
1057	int rc;
1058
1059	rc = ecryptfs_write_lower(ecryptfs_inode, data: virt,
1060	offset: 0, size: virt_len);
1061	if (rc < 0)
1062	printk(KERN_ERR "%s: Error attempting to write header "
1063	"information to lower file; rc = [%d]\n", __func__, rc);
1064	else
1065	rc = 0;
1066	return rc;
1067	}
1068
1069	static int
1070	ecryptfs_write_metadata_to_xattr(struct dentry *ecryptfs_dentry,
1071	struct inode *ecryptfs_inode,
1072	char *page_virt, size_t size)
1073	{
1074	int rc;
1075	struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry: ecryptfs_dentry);
1076	struct inode *lower_inode = d_inode(dentry: lower_dentry);
1077
1078	if (!(lower_inode->i_opflags & IOP_XATTR)) {
1079	rc = -EOPNOTSUPP;
1080	goto out;
1081	}
1082
1083	inode_lock(inode: lower_inode);
1084	rc = __vfs_setxattr(&nop_mnt_idmap, lower_dentry, lower_inode,
1085	ECRYPTFS_XATTR_NAME, page_virt, size, 0);
1086	if (!rc && ecryptfs_inode)
1087	fsstack_copy_attr_all(dest: ecryptfs_inode, src: lower_inode);
1088	inode_unlock(inode: lower_inode);
1089	out:
1090	return rc;
1091	}
1092
1093	static unsigned long ecryptfs_get_zeroed_pages(gfp_t gfp_mask,
1094	unsigned int order)
1095	{
1096	struct page *page;
1097
1098	page = alloc_pages(gfp: gfp_mask | __GFP_ZERO, order);
1099	if (page)
1100	return (unsigned long) page_address(page);
1101	return 0;
1102	}
1103
1104	/**
1105	* ecryptfs_write_metadata
1106	* @ecryptfs_dentry: The eCryptfs dentry, which should be negative
1107	* @ecryptfs_inode: The newly created eCryptfs inode
1108	*
1109	* Write the file headers out. This will likely involve a userspace
1110	* callout, in which the session key is encrypted with one or more
1111	* public keys and/or the passphrase necessary to do the encryption is
1112	* retrieved via a prompt. Exactly what happens at this point should
1113	* be policy-dependent.
1114	*
1115	* Returns zero on success; non-zero on error
1116	*/
1117	int ecryptfs_write_metadata(struct dentry *ecryptfs_dentry,
1118	struct inode *ecryptfs_inode)
1119	{
1120	struct ecryptfs_crypt_stat *crypt_stat =
1121	&ecryptfs_inode_to_private(inode: ecryptfs_inode)->crypt_stat;
1122	unsigned int order;
1123	char *virt;
1124	size_t virt_len;
1125	size_t size = 0;
1126	int rc = 0;
1127
1128	if (likely(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
1129	if (!(crypt_stat->flags & ECRYPTFS_KEY_VALID)) {
1130	printk(KERN_ERR "Key is invalid; bailing out\n");
1131	rc = -EINVAL;
1132	goto out;
1133	}
1134	} else {
1135	printk(KERN_WARNING "%s: Encrypted flag not set\n",
1136	__func__);
1137	rc = -EINVAL;
1138	goto out;
1139	}
1140	virt_len = crypt_stat->metadata_size;
1141	order = get_order(size: virt_len);
1142	/* Released in this function */
1143	virt = (char *)ecryptfs_get_zeroed_pages(GFP_KERNEL, order);
1144	if (!virt) {
1145	printk(KERN_ERR "%s: Out of memory\n", __func__);
1146	rc = -ENOMEM;
1147	goto out;
1148	}
1149	/* Zeroed page ensures the in-header unencrypted i_size is set to 0 */
1150	rc = ecryptfs_write_headers_virt(page_virt: virt, max: virt_len, size: &size, crypt_stat,
1151	ecryptfs_dentry);
1152	if (unlikely(rc)) {
1153	printk(KERN_ERR "%s: Error whilst writing headers; rc = [%d]\n",
1154	__func__, rc);
1155	goto out_free;
1156	}
1157	if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
1158	rc = ecryptfs_write_metadata_to_xattr(ecryptfs_dentry, ecryptfs_inode,
1159	page_virt: virt, size);
1160	else
1161	rc = ecryptfs_write_metadata_to_contents(ecryptfs_inode, virt,
1162	virt_len);
1163	if (rc) {
1164	printk(KERN_ERR "%s: Error writing metadata out to lower file; "
1165	"rc = [%d]\n", __func__, rc);
1166	goto out_free;
1167	}
1168	out_free:
1169	free_pages(addr: (unsigned long)virt, order);
1170	out:
1171	return rc;
1172	}
1173
1174	#define ECRYPTFS_DONT_VALIDATE_HEADER_SIZE 0
1175	#define ECRYPTFS_VALIDATE_HEADER_SIZE 1
1176	static int parse_header_metadata(struct ecryptfs_crypt_stat *crypt_stat,
1177	char *virt, int *bytes_read,
1178	int validate_header_size)
1179	{
1180	int rc = 0;
1181	u32 header_extent_size;
1182	u16 num_header_extents_at_front;
1183
1184	header_extent_size = get_unaligned_be32(p: virt);
1185	virt += sizeof(__be32);
1186	num_header_extents_at_front = get_unaligned_be16(p: virt);
1187	crypt_stat->metadata_size = (((size_t)num_header_extents_at_front
1188	* (size_t)header_extent_size));
1189	(*bytes_read) = (sizeof(__be32) + sizeof(__be16));
1190	if ((validate_header_size == ECRYPTFS_VALIDATE_HEADER_SIZE)
1191	&& (crypt_stat->metadata_size
1192	< ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE)) {
1193	rc = -EINVAL;
1194	printk(KERN_WARNING "Invalid header size: [%zd]\n",
1195	crypt_stat->metadata_size);
1196	}
1197	return rc;
1198	}
1199
1200	/**
1201	* set_default_header_data
1202	* @crypt_stat: The cryptographic context
1203	*
1204	* For version 0 file format; this function is only for backwards
1205	* compatibility for files created with the prior versions of
1206	* eCryptfs.
1207	*/
1208	static void set_default_header_data(struct ecryptfs_crypt_stat *crypt_stat)
1209	{
1210	crypt_stat->metadata_size = ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
1211	}
1212
1213	void ecryptfs_i_size_init(const char *page_virt, struct inode *inode)
1214	{
1215	struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
1216	struct ecryptfs_crypt_stat *crypt_stat;
1217	u64 file_size;
1218
1219	crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
1220	mount_crypt_stat =
1221	&ecryptfs_superblock_to_private(sb: inode->i_sb)->mount_crypt_stat;
1222	if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED) {
1223	file_size = i_size_read(inode: ecryptfs_inode_to_lower(inode));
1224	if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
1225	file_size += crypt_stat->metadata_size;
1226	} else
1227	file_size = get_unaligned_be64(p: page_virt);
1228	i_size_write(inode, i_size: (loff_t)file_size);
1229	crypt_stat->flags |= ECRYPTFS_I_SIZE_INITIALIZED;
1230	}
1231
1232	/**
1233	* ecryptfs_read_headers_virt
1234	* @page_virt: The virtual address into which to read the headers
1235	* @crypt_stat: The cryptographic context
1236	* @ecryptfs_dentry: The eCryptfs dentry
1237	* @validate_header_size: Whether to validate the header size while reading
1238	*
1239	* Read/parse the header data. The header format is detailed in the
1240	* comment block for the ecryptfs_write_headers_virt() function.
1241	*
1242	* Returns zero on success
1243	*/
1244	static int ecryptfs_read_headers_virt(char *page_virt,
1245	struct ecryptfs_crypt_stat *crypt_stat,
1246	struct dentry *ecryptfs_dentry,
1247	int validate_header_size)
1248	{
1249	int rc = 0;
1250	int offset;
1251	int bytes_read;
1252
1253	ecryptfs_set_default_sizes(crypt_stat);
1254	crypt_stat->mount_crypt_stat = &ecryptfs_superblock_to_private(
1255	sb: ecryptfs_dentry->d_sb)->mount_crypt_stat;
1256	offset = ECRYPTFS_FILE_SIZE_BYTES;
1257	rc = ecryptfs_validate_marker(data: page_virt + offset);
1258	if (rc)
1259	goto out;
1260	if (!(crypt_stat->flags & ECRYPTFS_I_SIZE_INITIALIZED))
1261	ecryptfs_i_size_init(page_virt, inode: d_inode(dentry: ecryptfs_dentry));
1262	offset += MAGIC_ECRYPTFS_MARKER_SIZE_BYTES;
1263	ecryptfs_process_flags(crypt_stat, page_virt: (page_virt + offset), bytes_read: &bytes_read);
1264	if (crypt_stat->file_version > ECRYPTFS_SUPPORTED_FILE_VERSION) {
1265	ecryptfs_printk(KERN_WARNING, "File version is [%d]; only "
1266	"file version [%d] is supported by this "
1267	"version of eCryptfs\n",
1268	crypt_stat->file_version,
1269	ECRYPTFS_SUPPORTED_FILE_VERSION);
1270	rc = -EINVAL;
1271	goto out;
1272	}
1273	offset += bytes_read;
1274	if (crypt_stat->file_version >= 1) {
1275	rc = parse_header_metadata(crypt_stat, virt: (page_virt + offset),
1276	bytes_read: &bytes_read, validate_header_size);
1277	if (rc) {
1278	ecryptfs_printk(KERN_WARNING, "Error reading header "
1279	"metadata; rc = [%d]\n", rc);
1280	}
1281	offset += bytes_read;
1282	} else
1283	set_default_header_data(crypt_stat);
1284	rc = ecryptfs_parse_packet_set(crypt_stat, src: (page_virt + offset),
1285	ecryptfs_dentry);
1286	out:
1287	return rc;
1288	}
1289
1290	/**
1291	* ecryptfs_read_xattr_region
1292	* @page_virt: The vitual address into which to read the xattr data
1293	* @ecryptfs_inode: The eCryptfs inode
1294	*
1295	* Attempts to read the crypto metadata from the extended attribute
1296	* region of the lower file.
1297	*
1298	* Returns zero on success; non-zero on error
1299	*/
1300	int ecryptfs_read_xattr_region(char *page_virt, struct inode *ecryptfs_inode)
1301	{
1302	struct dentry *lower_dentry =
1303	ecryptfs_inode_to_private(inode: ecryptfs_inode)->lower_file->f_path.dentry;
1304	ssize_t size;
1305	int rc = 0;
1306
1307	size = ecryptfs_getxattr_lower(lower_dentry,
1308	lower_inode: ecryptfs_inode_to_lower(inode: ecryptfs_inode),
1309	ECRYPTFS_XATTR_NAME,
1310	value: page_virt, ECRYPTFS_DEFAULT_EXTENT_SIZE);
1311	if (size < 0) {
1312	if (unlikely(ecryptfs_verbosity > 0))
1313	printk(KERN_INFO "Error attempting to read the [%s] "
1314	"xattr from the lower file; return value = "
1315	"[%zd]\n", ECRYPTFS_XATTR_NAME, size);
1316	rc = -EINVAL;
1317	goto out;
1318	}
1319	out:
1320	return rc;
1321	}
1322
1323	int ecryptfs_read_and_validate_xattr_region(struct dentry *dentry,
1324	struct inode *inode)
1325	{
1326	u8 file_size[ECRYPTFS_SIZE_AND_MARKER_BYTES];
1327	u8 *marker = file_size + ECRYPTFS_FILE_SIZE_BYTES;
1328	int rc;
1329
1330	rc = ecryptfs_getxattr_lower(lower_dentry: ecryptfs_dentry_to_lower(dentry),
1331	lower_inode: ecryptfs_inode_to_lower(inode),
1332	ECRYPTFS_XATTR_NAME, value: file_size,
1333	ECRYPTFS_SIZE_AND_MARKER_BYTES);
1334	if (rc < 0)
1335	return rc;
1336	else if (rc < ECRYPTFS_SIZE_AND_MARKER_BYTES)
1337	return -EINVAL;
1338	rc = ecryptfs_validate_marker(data: marker);
1339	if (!rc)
1340	ecryptfs_i_size_init(page_virt: file_size, inode);
1341	return rc;
1342	}
1343
1344	/*
1345	* ecryptfs_read_metadata
1346	*
1347	* Common entry point for reading file metadata. From here, we could
1348	* retrieve the header information from the header region of the file,
1349	* the xattr region of the file, or some other repository that is
1350	* stored separately from the file itself. The current implementation
1351	* supports retrieving the metadata information from the file contents
1352	* and from the xattr region.
1353	*
1354	* Returns zero if valid headers found and parsed; non-zero otherwise
1355	*/
1356	int ecryptfs_read_metadata(struct dentry *ecryptfs_dentry)
1357	{
1358	int rc;
1359	char *page_virt;
1360	struct inode *ecryptfs_inode = d_inode(dentry: ecryptfs_dentry);
1361	struct ecryptfs_crypt_stat *crypt_stat =
1362	&ecryptfs_inode_to_private(inode: ecryptfs_inode)->crypt_stat;
1363	struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
1364	&ecryptfs_superblock_to_private(
1365	sb: ecryptfs_dentry->d_sb)->mount_crypt_stat;
1366
1367	ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
1368	mount_crypt_stat);
1369	/* Read the first page from the underlying file */
1370	page_virt = kmem_cache_alloc(cachep: ecryptfs_header_cache, GFP_USER);
1371	if (!page_virt) {
1372	rc = -ENOMEM;
1373	goto out;
1374	}
1375	rc = ecryptfs_read_lower(data: page_virt, offset: 0, size: crypt_stat->extent_size,
1376	ecryptfs_inode);
1377	if (rc >= 0)
1378	rc = ecryptfs_read_headers_virt(page_virt, crypt_stat,
1379	ecryptfs_dentry,
1380	ECRYPTFS_VALIDATE_HEADER_SIZE);
1381	if (rc) {
1382	/* metadata is not in the file header, so try xattrs */
1383	memset(page_virt, 0, PAGE_SIZE);
1384	rc = ecryptfs_read_xattr_region(page_virt, ecryptfs_inode);
1385	if (rc) {
1386	printk(KERN_DEBUG "Valid eCryptfs headers not found in "
1387	"file header region or xattr region, inode %lu\n",
1388	ecryptfs_inode->i_ino);
1389	rc = -EINVAL;
1390	goto out;
1391	}
1392	rc = ecryptfs_read_headers_virt(page_virt, crypt_stat,
1393	ecryptfs_dentry,
1394	ECRYPTFS_DONT_VALIDATE_HEADER_SIZE);
1395	if (rc) {
1396	printk(KERN_DEBUG "Valid eCryptfs headers not found in "
1397	"file xattr region either, inode %lu\n",
1398	ecryptfs_inode->i_ino);
1399	rc = -EINVAL;
1400	}
1401	if (crypt_stat->mount_crypt_stat->flags
1402	& ECRYPTFS_XATTR_METADATA_ENABLED) {
1403	crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
1404	} else {
1405	printk(KERN_WARNING "Attempt to access file with "
1406	"crypto metadata only in the extended attribute "
1407	"region, but eCryptfs was mounted without "
1408	"xattr support enabled. eCryptfs will not treat "
1409	"this like an encrypted file, inode %lu\n",
1410	ecryptfs_inode->i_ino);
1411	rc = -EINVAL;
1412	}
1413	}
1414	out:
1415	if (page_virt) {
1416	memset(page_virt, 0, PAGE_SIZE);
1417	kmem_cache_free(s: ecryptfs_header_cache, objp: page_virt);
1418	}
1419	return rc;
1420	}
1421
1422	/*
1423	* ecryptfs_encrypt_filename - encrypt filename
1424	*
1425	* CBC-encrypts the filename. We do not want to encrypt the same
1426	* filename with the same key and IV, which may happen with hard
1427	* links, so we prepend random bits to each filename.
1428	*
1429	* Returns zero on success; non-zero otherwise
1430	*/
1431	static int
1432	ecryptfs_encrypt_filename(struct ecryptfs_filename *filename,
1433	struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
1434	{
1435	int rc = 0;
1436
1437	filename->encrypted_filename = NULL;
1438	filename->encrypted_filename_size = 0;
1439	if (mount_crypt_stat && (mount_crypt_stat->flags
1440	& ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK)) {
1441	size_t packet_size;
1442	size_t remaining_bytes;
1443
1444	rc = ecryptfs_write_tag_70_packet(
1445	NULL, NULL,
1446	packet_size: &filename->encrypted_filename_size,
1447	mount_crypt_stat, NULL,
1448	filename_size: filename->filename_size);
1449	if (rc) {
1450	printk(KERN_ERR "%s: Error attempting to get packet "
1451	"size for tag 72; rc = [%d]\n", __func__,
1452	rc);
1453	filename->encrypted_filename_size = 0;
1454	goto out;
1455	}
1456	filename->encrypted_filename =
1457	kmalloc(size: filename->encrypted_filename_size, GFP_KERNEL);
1458	if (!filename->encrypted_filename) {
1459	rc = -ENOMEM;
1460	goto out;
1461	}
1462	remaining_bytes = filename->encrypted_filename_size;
1463	rc = ecryptfs_write_tag_70_packet(dest: filename->encrypted_filename,
1464	remaining_bytes: &remaining_bytes,
1465	packet_size: &packet_size,
1466	mount_crypt_stat,
1467	filename: filename->filename,
1468	filename_size: filename->filename_size);
1469	if (rc) {
1470	printk(KERN_ERR "%s: Error attempting to generate "
1471	"tag 70 packet; rc = [%d]\n", __func__,
1472	rc);
1473	kfree(objp: filename->encrypted_filename);
1474	filename->encrypted_filename = NULL;
1475	filename->encrypted_filename_size = 0;
1476	goto out;
1477	}
1478	filename->encrypted_filename_size = packet_size;
1479	} else {
1480	printk(KERN_ERR "%s: No support for requested filename "
1481	"encryption method in this release\n", __func__);
1482	rc = -EOPNOTSUPP;
1483	goto out;
1484	}
1485	out:
1486	return rc;
1487	}
1488
1489	static int ecryptfs_copy_filename(char **copied_name, size_t *copied_name_size,
1490	const char *name, size_t name_size)
1491	{
1492	int rc = 0;
1493
1494	(*copied_name) = kmalloc(size: (name_size + 1), GFP_KERNEL);
1495	if (!(*copied_name)) {
1496	rc = -ENOMEM;
1497	goto out;
1498	}
1499	memcpy((void *)(*copied_name), (void *)name, name_size);
1500	(*copied_name)[(name_size)] = '\0'; /* Only for convenience
1501	* in printing out the
1502	* string in debug
1503	* messages */
1504	(*copied_name_size) = name_size;
1505	out:
1506	return rc;
1507	}
1508
1509	/**
1510	* ecryptfs_process_key_cipher - Perform key cipher initialization.
1511	* @key_tfm: Crypto context for key material, set by this function
1512	* @cipher_name: Name of the cipher
1513	* @key_size: Size of the key in bytes
1514	*
1515	* Returns zero on success. Any crypto_tfm structs allocated here
1516	* should be released by other functions, such as on a superblock put
1517	* event, regardless of whether this function succeeds for fails.
1518	*/
1519	static int
1520	ecryptfs_process_key_cipher(struct crypto_skcipher **key_tfm,
1521	char *cipher_name, size_t *key_size)
1522	{
1523	char dummy_key[ECRYPTFS_MAX_KEY_BYTES];
1524	char *full_alg_name = NULL;
1525	int rc;
1526
1527	*key_tfm = NULL;
1528	if (*key_size > ECRYPTFS_MAX_KEY_BYTES) {
1529	rc = -EINVAL;
1530	printk(KERN_ERR "Requested key size is [%zd] bytes; maximum "
1531	"allowable is [%d]\n", *key_size, ECRYPTFS_MAX_KEY_BYTES);
1532	goto out;
1533	}
1534	rc = ecryptfs_crypto_api_algify_cipher_name(algified_name: &full_alg_name, cipher_name,
1535	chaining_modifier: "ecb");
1536	if (rc)
1537	goto out;
1538	*key_tfm = crypto_alloc_skcipher(alg_name: full_alg_name, type: 0, CRYPTO_ALG_ASYNC);
1539	if (IS_ERR(ptr: *key_tfm)) {
1540	rc = PTR_ERR(ptr: *key_tfm);
1541	printk(KERN_ERR "Unable to allocate crypto cipher with name "
1542	"[%s]; rc = [%d]\n", full_alg_name, rc);
1543	goto out;
1544	}
1545	crypto_skcipher_set_flags(tfm: *key_tfm, CRYPTO_TFM_REQ_FORBID_WEAK_KEYS);
1546	if (*key_size == 0)
1547	*key_size = crypto_skcipher_max_keysize(tfm: *key_tfm);
1548	get_random_bytes(buf: dummy_key, len: *key_size);
1549	rc = crypto_skcipher_setkey(tfm: *key_tfm, key: dummy_key, keylen: *key_size);
1550	if (rc) {
1551	printk(KERN_ERR "Error attempting to set key of size [%zd] for "
1552	"cipher [%s]; rc = [%d]\n", *key_size, full_alg_name,
1553	rc);
1554	rc = -EINVAL;
1555	goto out;
1556	}
1557	out:
1558	kfree(objp: full_alg_name);
1559	return rc;
1560	}
1561
1562	struct kmem_cache *ecryptfs_key_tfm_cache;
1563	static struct list_head key_tfm_list;
1564	DEFINE_MUTEX(key_tfm_list_mutex);
1565
1566	int __init ecryptfs_init_crypto(void)
1567	{
1568	INIT_LIST_HEAD(list: &key_tfm_list);
1569	return 0;
1570	}
1571
1572	/**
1573	* ecryptfs_destroy_crypto - free all cached key_tfms on key_tfm_list
1574	*
1575	* Called only at module unload time
1576	*/
1577	int ecryptfs_destroy_crypto(void)
1578	{
1579	struct ecryptfs_key_tfm *key_tfm, *key_tfm_tmp;
1580
1581	mutex_lock(&key_tfm_list_mutex);
1582	list_for_each_entry_safe(key_tfm, key_tfm_tmp, &key_tfm_list,
1583	key_tfm_list) {
1584	list_del(entry: &key_tfm->key_tfm_list);
1585	crypto_free_skcipher(tfm: key_tfm->key_tfm);
1586	kmem_cache_free(s: ecryptfs_key_tfm_cache, objp: key_tfm);
1587	}
1588	mutex_unlock(lock: &key_tfm_list_mutex);
1589	return 0;
1590	}
1591
1592	int
1593	ecryptfs_add_new_key_tfm(struct ecryptfs_key_tfm **key_tfm, char *cipher_name,
1594	size_t key_size)
1595	{
1596	struct ecryptfs_key_tfm *tmp_tfm;
1597	int rc = 0;
1598
1599	BUG_ON(!mutex_is_locked(&key_tfm_list_mutex));
1600
1601	tmp_tfm = kmem_cache_alloc(cachep: ecryptfs_key_tfm_cache, GFP_KERNEL);
1602	if (key_tfm)
1603	(*key_tfm) = tmp_tfm;
1604	if (!tmp_tfm) {
1605	rc = -ENOMEM;
1606	goto out;
1607	}
1608	mutex_init(&tmp_tfm->key_tfm_mutex);
1609	strncpy(p: tmp_tfm->cipher_name, q: cipher_name,
1610	ECRYPTFS_MAX_CIPHER_NAME_SIZE);
1611	tmp_tfm->cipher_name[ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
1612	tmp_tfm->key_size = key_size;
1613	rc = ecryptfs_process_key_cipher(key_tfm: &tmp_tfm->key_tfm,
1614	cipher_name: tmp_tfm->cipher_name,
1615	key_size: &tmp_tfm->key_size);
1616	if (rc) {
1617	printk(KERN_ERR "Error attempting to initialize key TFM "
1618	"cipher with name = [%s]; rc = [%d]\n",
1619	tmp_tfm->cipher_name, rc);
1620	kmem_cache_free(s: ecryptfs_key_tfm_cache, objp: tmp_tfm);
1621	if (key_tfm)
1622	(*key_tfm) = NULL;
1623	goto out;
1624	}
1625	list_add(new: &tmp_tfm->key_tfm_list, head: &key_tfm_list);
1626	out:
1627	return rc;
1628	}
1629
1630	/**
1631	* ecryptfs_tfm_exists - Search for existing tfm for cipher_name.
1632	* @cipher_name: the name of the cipher to search for
1633	* @key_tfm: set to corresponding tfm if found
1634	*
1635	* Searches for cached key_tfm matching @cipher_name
1636	* Must be called with &key_tfm_list_mutex held
1637	* Returns 1 if found, with @key_tfm set
1638	* Returns 0 if not found, with @key_tfm set to NULL
1639	*/
1640	int ecryptfs_tfm_exists(char *cipher_name, struct ecryptfs_key_tfm **key_tfm)
1641	{
1642	struct ecryptfs_key_tfm *tmp_key_tfm;
1643
1644	BUG_ON(!mutex_is_locked(&key_tfm_list_mutex));
1645
1646	list_for_each_entry(tmp_key_tfm, &key_tfm_list, key_tfm_list) {
1647	if (strcmp(tmp_key_tfm->cipher_name, cipher_name) == 0) {
1648	if (key_tfm)
1649	(*key_tfm) = tmp_key_tfm;
1650	return 1;
1651	}
1652	}
1653	if (key_tfm)
1654	(*key_tfm) = NULL;
1655	return 0;
1656	}
1657
1658	/**
1659	* ecryptfs_get_tfm_and_mutex_for_cipher_name
1660	*
1661	* @tfm: set to cached tfm found, or new tfm created
1662	* @tfm_mutex: set to mutex for cached tfm found, or new tfm created
1663	* @cipher_name: the name of the cipher to search for and/or add
1664	*
1665	* Sets pointers to @tfm & @tfm_mutex matching @cipher_name.
1666	* Searches for cached item first, and creates new if not found.
1667	* Returns 0 on success, non-zero if adding new cipher failed
1668	*/
1669	int ecryptfs_get_tfm_and_mutex_for_cipher_name(struct crypto_skcipher **tfm,
1670	struct mutex **tfm_mutex,
1671	char *cipher_name)
1672	{
1673	struct ecryptfs_key_tfm *key_tfm;
1674	int rc = 0;
1675
1676	(*tfm) = NULL;
1677	(*tfm_mutex) = NULL;
1678
1679	mutex_lock(&key_tfm_list_mutex);
1680	if (!ecryptfs_tfm_exists(cipher_name, key_tfm: &key_tfm)) {
1681	rc = ecryptfs_add_new_key_tfm(key_tfm: &key_tfm, cipher_name, key_size: 0);
1682	if (rc) {
1683	printk(KERN_ERR "Error adding new key_tfm to list; "
1684	"rc = [%d]\n", rc);
1685	goto out;
1686	}
1687	}
1688	(*tfm) = key_tfm->key_tfm;
1689	(*tfm_mutex) = &key_tfm->key_tfm_mutex;
1690	out:
1691	mutex_unlock(lock: &key_tfm_list_mutex);
1692	return rc;
1693	}
1694
1695	/* 64 characters forming a 6-bit target field */
1696	static unsigned char *portable_filename_chars = ("-.0123456789ABCD"
1697	"EFGHIJKLMNOPQRST"
1698	"UVWXYZabcdefghij"
1699	"klmnopqrstuvwxyz");
1700
1701	/* We could either offset on every reverse map or just pad some 0x00's
1702	* at the front here */
1703	static const unsigned char filename_rev_map[256] = {
1704	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 7 */
1705	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 15 */
1706	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 23 */
1707	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 31 */
1708	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 39 */
1709	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, /* 47 */
1710	0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, /* 55 */
1711	0x0A, 0x0B, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 63 */
1712	0x00, 0x0C, 0x0D, 0x0E, 0x0F, 0x10, 0x11, 0x12, /* 71 */
1713	0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1A, /* 79 */
1714	0x1B, 0x1C, 0x1D, 0x1E, 0x1F, 0x20, 0x21, 0x22, /* 87 */
1715	0x23, 0x24, 0x25, 0x00, 0x00, 0x00, 0x00, 0x00, /* 95 */
1716	0x00, 0x26, 0x27, 0x28, 0x29, 0x2A, 0x2B, 0x2C, /* 103 */
1717	0x2D, 0x2E, 0x2F, 0x30, 0x31, 0x32, 0x33, 0x34, /* 111 */
1718	0x35, 0x36, 0x37, 0x38, 0x39, 0x3A, 0x3B, 0x3C, /* 119 */
1719	0x3D, 0x3E, 0x3F /* 123 - 255 initialized to 0x00 */
1720	};
1721
1722	/**
1723	* ecryptfs_encode_for_filename
1724	* @dst: Destination location for encoded filename
1725	* @dst_size: Size of the encoded filename in bytes
1726	* @src: Source location for the filename to encode
1727	* @src_size: Size of the source in bytes
1728	*/
1729	static void ecryptfs_encode_for_filename(unsigned char *dst, size_t *dst_size,
1730	unsigned char *src, size_t src_size)
1731	{
1732	size_t num_blocks;
1733	size_t block_num = 0;
1734	size_t dst_offset = 0;
1735	unsigned char last_block[3];
1736
1737	if (src_size == 0) {
1738	(*dst_size) = 0;
1739	goto out;
1740	}
1741	num_blocks = (src_size / 3);
1742	if ((src_size % 3) == 0) {
1743	memcpy(last_block, (&src[src_size - 3]), 3);
1744	} else {
1745	num_blocks++;
1746	last_block[2] = 0x00;
1747	switch (src_size % 3) {
1748	case 1:
1749	last_block[0] = src[src_size - 1];
1750	last_block[1] = 0x00;
1751	break;
1752	case 2:
1753	last_block[0] = src[src_size - 2];
1754	last_block[1] = src[src_size - 1];
1755	}
1756	}
1757	(*dst_size) = (num_blocks * 4);
1758	if (!dst)
1759	goto out;
1760	while (block_num < num_blocks) {
1761	unsigned char *src_block;
1762	unsigned char dst_block[4];
1763
1764	if (block_num == (num_blocks - 1))
1765	src_block = last_block;
1766	else
1767	src_block = &src[block_num * 3];
1768	dst_block[0] = ((src_block[0] >> 2) & 0x3F);
1769	dst_block[1] = (((src_block[0] << 4) & 0x30)
1770	| ((src_block[1] >> 4) & 0x0F));
1771	dst_block[2] = (((src_block[1] << 2) & 0x3C)
1772	| ((src_block[2] >> 6) & 0x03));
1773	dst_block[3] = (src_block[2] & 0x3F);
1774	dst[dst_offset++] = portable_filename_chars[dst_block[0]];
1775	dst[dst_offset++] = portable_filename_chars[dst_block[1]];
1776	dst[dst_offset++] = portable_filename_chars[dst_block[2]];
1777	dst[dst_offset++] = portable_filename_chars[dst_block[3]];
1778	block_num++;
1779	}
1780	out:
1781	return;
1782	}
1783
1784	static size_t ecryptfs_max_decoded_size(size_t encoded_size)
1785	{
1786	/* Not exact; conservatively long. Every block of 4
1787	* encoded characters decodes into a block of 3
1788	* decoded characters. This segment of code provides
1789	* the caller with the maximum amount of allocated
1790	* space that @dst will need to point to in a
1791	* subsequent call. */
1792	return ((encoded_size + 1) * 3) / 4;
1793	}
1794
1795	/**
1796	* ecryptfs_decode_from_filename
1797	* @dst: If NULL, this function only sets @dst_size and returns. If
1798	* non-NULL, this function decodes the encoded octets in @src
1799	* into the memory that @dst points to.
1800	* @dst_size: Set to the size of the decoded string.
1801	* @src: The encoded set of octets to decode.
1802	* @src_size: The size of the encoded set of octets to decode.
1803	*/
1804	static void
1805	ecryptfs_decode_from_filename(unsigned char *dst, size_t *dst_size,
1806	const unsigned char *src, size_t src_size)
1807	{
1808	u8 current_bit_offset = 0;
1809	size_t src_byte_offset = 0;
1810	size_t dst_byte_offset = 0;
1811
1812	if (!dst) {
1813	(*dst_size) = ecryptfs_max_decoded_size(encoded_size: src_size);
1814	goto out;
1815	}
1816	while (src_byte_offset < src_size) {
1817	unsigned char src_byte =
1818	filename_rev_map[(int)src[src_byte_offset]];
1819
1820	switch (current_bit_offset) {
1821	case 0:
1822	dst[dst_byte_offset] = (src_byte << 2);
1823	current_bit_offset = 6;
1824	break;
1825	case 6:
1826	dst[dst_byte_offset++] |= (src_byte >> 4);
1827	dst[dst_byte_offset] = ((src_byte & 0xF)
1828	<< 4);
1829	current_bit_offset = 4;
1830	break;
1831	case 4:
1832	dst[dst_byte_offset++] |= (src_byte >> 2);
1833	dst[dst_byte_offset] = (src_byte << 6);
1834	current_bit_offset = 2;
1835	break;
1836	case 2:
1837	dst[dst_byte_offset++] |= (src_byte);
1838	current_bit_offset = 0;
1839	break;
1840	}
1841	src_byte_offset++;
1842	}
1843	(*dst_size) = dst_byte_offset;
1844	out:
1845	return;
1846	}
1847
1848	/**
1849	* ecryptfs_encrypt_and_encode_filename - converts a plaintext file name to cipher text
1850	* @encoded_name: The encrypted name
1851	* @encoded_name_size: Length of the encrypted name
1852	* @mount_crypt_stat: The crypt_stat struct associated with the file name to encode
1853	* @name: The plaintext name
1854	* @name_size: The length of the plaintext name
1855	*
1856	* Encrypts and encodes a filename into something that constitutes a
1857	* valid filename for a filesystem, with printable characters.
1858	*
1859	* We assume that we have a properly initialized crypto context,
1860	* pointed to by crypt_stat->tfm.
1861	*
1862	* Returns zero on success; non-zero on otherwise
1863	*/
1864	int ecryptfs_encrypt_and_encode_filename(
1865	char **encoded_name,
1866	size_t *encoded_name_size,
1867	struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
1868	const char *name, size_t name_size)
1869	{
1870	size_t encoded_name_no_prefix_size;
1871	int rc = 0;
1872
1873	(*encoded_name) = NULL;
1874	(*encoded_name_size) = 0;
1875	if (mount_crypt_stat && (mount_crypt_stat->flags
1876	& ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)) {
1877	struct ecryptfs_filename *filename;
1878
1879	filename = kzalloc(size: sizeof(*filename), GFP_KERNEL);
1880	if (!filename) {
1881	rc = -ENOMEM;
1882	goto out;
1883	}
1884	filename->filename = (char *)name;
1885	filename->filename_size = name_size;
1886	rc = ecryptfs_encrypt_filename(filename, mount_crypt_stat);
1887	if (rc) {
1888	printk(KERN_ERR "%s: Error attempting to encrypt "
1889	"filename; rc = [%d]\n", __func__, rc);
1890	kfree(objp: filename);
1891	goto out;
1892	}
1893	ecryptfs_encode_for_filename(
1894	NULL, dst_size: &encoded_name_no_prefix_size,
1895	src: filename->encrypted_filename,
1896	src_size: filename->encrypted_filename_size);
1897	if (mount_crypt_stat
1898	&& (mount_crypt_stat->flags
1899	& ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK))
1900	(*encoded_name_size) =
1901	(ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE
1902	+ encoded_name_no_prefix_size);
1903	else
1904	(*encoded_name_size) =
1905	(ECRYPTFS_FEK_ENCRYPTED_FILENAME_PREFIX_SIZE
1906	+ encoded_name_no_prefix_size);
1907	(*encoded_name) = kmalloc(size: (*encoded_name_size) + 1, GFP_KERNEL);
1908	if (!(*encoded_name)) {
1909	rc = -ENOMEM;
1910	kfree(objp: filename->encrypted_filename);
1911	kfree(objp: filename);
1912	goto out;
1913	}
1914	if (mount_crypt_stat
1915	&& (mount_crypt_stat->flags
1916	& ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK)) {
1917	memcpy((*encoded_name),
1918	ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX,
1919	ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE);
1920	ecryptfs_encode_for_filename(
1921	dst: ((*encoded_name)
1922	+ ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE),
1923	dst_size: &encoded_name_no_prefix_size,
1924	src: filename->encrypted_filename,
1925	src_size: filename->encrypted_filename_size);
1926	(*encoded_name_size) =
1927	(ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE
1928	+ encoded_name_no_prefix_size);
1929	(*encoded_name)[(*encoded_name_size)] = '\0';
1930	} else {
1931	rc = -EOPNOTSUPP;
1932	}
1933	if (rc) {
1934	printk(KERN_ERR "%s: Error attempting to encode "
1935	"encrypted filename; rc = [%d]\n", __func__,
1936	rc);
1937	kfree(objp: (*encoded_name));
1938	(*encoded_name) = NULL;
1939	(*encoded_name_size) = 0;
1940	}
1941	kfree(objp: filename->encrypted_filename);
1942	kfree(objp: filename);
1943	} else {
1944	rc = ecryptfs_copy_filename(copied_name: encoded_name,
1945	copied_name_size: encoded_name_size,
1946	name, name_size);
1947	}
1948	out:
1949	return rc;
1950	}
1951
1952	static bool is_dot_dotdot(const char *name, size_t name_size)
1953	{
1954	if (name_size == 1 && name[0] == '.')
1955	return true;
1956	else if (name_size == 2 && name[0] == '.' && name[1] == '.')
1957	return true;
1958
1959	return false;
1960	}
1961
1962	/**
1963	* ecryptfs_decode_and_decrypt_filename - converts the encoded cipher text name to decoded plaintext
1964	* @plaintext_name: The plaintext name
1965	* @plaintext_name_size: The plaintext name size
1966	* @sb: Ecryptfs's super_block
1967	* @name: The filename in cipher text
1968	* @name_size: The cipher text name size
1969	*
1970	* Decrypts and decodes the filename.
1971	*
1972	* Returns zero on error; non-zero otherwise
1973	*/
1974	int ecryptfs_decode_and_decrypt_filename(char **plaintext_name,
1975	size_t *plaintext_name_size,
1976	struct super_block *sb,
1977	const char *name, size_t name_size)
1978	{
1979	struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
1980	&ecryptfs_superblock_to_private(sb)->mount_crypt_stat;
1981	char *decoded_name;
1982	size_t decoded_name_size;
1983	size_t packet_size;
1984	int rc = 0;
1985
1986	if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) &&
1987	!(mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)) {
1988	if (is_dot_dotdot(name, name_size)) {
1989	rc = ecryptfs_copy_filename(copied_name: plaintext_name,
1990	copied_name_size: plaintext_name_size,
1991	name, name_size);
1992	goto out;
1993	}
1994
1995	if (name_size <= ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE ||
1996	strncmp(name, ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX,
1997	ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE)) {
1998	rc = -EINVAL;
1999	goto out;
2000	}
2001
2002	name += ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE;
2003	name_size -= ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE;
2004	ecryptfs_decode_from_filename(NULL, dst_size: &decoded_name_size,
2005	src: name, src_size: name_size);
2006	decoded_name = kmalloc(size: decoded_name_size, GFP_KERNEL);
2007	if (!decoded_name) {
2008	rc = -ENOMEM;
2009	goto out;
2010	}
2011	ecryptfs_decode_from_filename(dst: decoded_name, dst_size: &decoded_name_size,
2012	src: name, src_size: name_size);
2013	rc = ecryptfs_parse_tag_70_packet(filename: plaintext_name,
2014	filename_size: plaintext_name_size,
2015	packet_size: &packet_size,
2016	mount_crypt_stat,
2017	data: decoded_name,
2018	max_packet_size: decoded_name_size);
2019	if (rc) {
2020	ecryptfs_printk(KERN_DEBUG,
2021	"%s: Could not parse tag 70 packet from filename\n",
2022	__func__);
2023	goto out_free;
2024	}
2025	} else {
2026	rc = ecryptfs_copy_filename(copied_name: plaintext_name,
2027	copied_name_size: plaintext_name_size,
2028	name, name_size);
2029	goto out;
2030	}
2031	out_free:
2032	kfree(objp: decoded_name);
2033	out:
2034	return rc;
2035	}
2036
2037	#define ENC_NAME_MAX_BLOCKLEN_8_OR_16 143
2038
2039	int ecryptfs_set_f_namelen(long *namelen, long lower_namelen,
2040	struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
2041	{
2042	struct crypto_skcipher *tfm;
2043	struct mutex *tfm_mutex;
2044	size_t cipher_blocksize;
2045	int rc;
2046
2047	if (!(mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)) {
2048	(*namelen) = lower_namelen;
2049	return 0;
2050	}
2051
2052	rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(tfm: &tfm, tfm_mutex: &tfm_mutex,
2053	cipher_name: mount_crypt_stat->global_default_fn_cipher_name);
2054	if (unlikely(rc)) {
2055	(*namelen) = 0;
2056	return rc;
2057	}
2058
2059	mutex_lock(tfm_mutex);
2060	cipher_blocksize = crypto_skcipher_blocksize(tfm);
2061	mutex_unlock(lock: tfm_mutex);
2062
2063	/* Return an exact amount for the common cases */
2064	if (lower_namelen == NAME_MAX
2065	&& (cipher_blocksize == 8 || cipher_blocksize == 16)) {
2066	(*namelen) = ENC_NAME_MAX_BLOCKLEN_8_OR_16;
2067	return 0;
2068	}
2069
2070	/* Return a safe estimate for the uncommon cases */
2071	(*namelen) = lower_namelen;
2072	(*namelen) -= ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE;
2073	/* Since this is the max decoded size, subtract 1 "decoded block" len */
2074	(*namelen) = ecryptfs_max_decoded_size(encoded_size: *namelen) - 3;
2075	(*namelen) -= ECRYPTFS_TAG_70_MAX_METADATA_SIZE;
2076	(*namelen) -= ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES;
2077	/* Worst case is that the filename is padded nearly a full block size */
2078	(*namelen) -= cipher_blocksize - 1;
2079
2080	if ((*namelen) < 0)
2081	(*namelen) = 0;
2082
2083	return 0;
2084	}
2085