blob: 04d7b3fa1ac6cd7679237cd2188a385c67bf960c [file] [log] [blame]
Michael Halcrow237fead2006-10-04 02:16:22 -07001/**
2 * eCryptfs: Linux filesystem encryption layer
3 * This is where eCryptfs coordinates the symmetric encryption and
4 * decryption of the file data as it passes between the lower
5 * encrypted file and the upper decrypted file.
6 *
7 * Copyright (C) 1997-2003 Erez Zadok
8 * Copyright (C) 2001-2003 Stony Brook University
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08009 * Copyright (C) 2004-2007 International Business Machines Corp.
Michael Halcrow237fead2006-10-04 02:16:22 -070010 * Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
11 *
12 * This program is free software; you can redistribute it and/or
13 * modify it under the terms of the GNU General Public License as
14 * published by the Free Software Foundation; either version 2 of the
15 * License, or (at your option) any later version.
16 *
17 * This program is distributed in the hope that it will be useful, but
18 * WITHOUT ANY WARRANTY; without even the implied warranty of
19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
20 * General Public License for more details.
21 *
22 * You should have received a copy of the GNU General Public License
23 * along with this program; if not, write to the Free Software
24 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
25 * 02111-1307, USA.
26 */
27
28#include <linux/pagemap.h>
29#include <linux/writeback.h>
30#include <linux/page-flags.h>
31#include <linux/mount.h>
32#include <linux/file.h>
33#include <linux/crypto.h>
34#include <linux/scatterlist.h>
Harvey Harrison0a688ad2008-07-23 21:30:07 -070035#include <asm/unaligned.h>
Michael Halcrow237fead2006-10-04 02:16:22 -070036#include "ecryptfs_kernel.h"
37
Michael Halcrow237fead2006-10-04 02:16:22 -070038/**
Michael Halcrow16a72c42007-10-16 01:28:14 -070039 * ecryptfs_get_locked_page
Michael Halcrow237fead2006-10-04 02:16:22 -070040 *
41 * Get one page from cache or lower f/s, return error otherwise.
42 *
Michael Halcrow16a72c42007-10-16 01:28:14 -070043 * Returns locked and up-to-date page (if ok), with increased
Michael Halcrow237fead2006-10-04 02:16:22 -070044 * refcnt.
45 */
Michael Halcrow16a72c42007-10-16 01:28:14 -070046struct page *ecryptfs_get_locked_page(struct file *file, loff_t index)
Michael Halcrow237fead2006-10-04 02:16:22 -070047{
Michael Halcrow237fead2006-10-04 02:16:22 -070048 struct dentry *dentry;
49 struct inode *inode;
50 struct address_space *mapping;
Michael Halcrow16a72c42007-10-16 01:28:14 -070051 struct page *page;
Michael Halcrow237fead2006-10-04 02:16:22 -070052
Josef "Jeff" Sipekbd243a42006-12-08 02:36:48 -080053 dentry = file->f_path.dentry;
Michael Halcrow237fead2006-10-04 02:16:22 -070054 inode = dentry->d_inode;
55 mapping = inode->i_mapping;
Michael Halcrow16a72c42007-10-16 01:28:14 -070056 page = read_mapping_page(mapping, index, (void *)file);
57 if (!IS_ERR(page))
58 lock_page(page);
59 return page;
Michael Halcrow237fead2006-10-04 02:16:22 -070060}
61
Michael Halcrow237fead2006-10-04 02:16:22 -070062/**
Michael Halcrow237fead2006-10-04 02:16:22 -070063 * ecryptfs_writepage
64 * @page: Page that is locked before this call is made
65 *
66 * Returns zero on success; non-zero otherwise
67 */
68static int ecryptfs_writepage(struct page *page, struct writeback_control *wbc)
69{
Michael Halcrow237fead2006-10-04 02:16:22 -070070 int rc;
71
Michael Halcrow0216f7f2007-10-16 01:28:08 -070072 rc = ecryptfs_encrypt_page(page);
Michael Halcrow237fead2006-10-04 02:16:22 -070073 if (rc) {
74 ecryptfs_printk(KERN_WARNING, "Error encrypting "
75 "page (upper index [0x%.16x])\n", page->index);
76 ClearPageUptodate(page);
77 goto out;
78 }
79 SetPageUptodate(page);
80 unlock_page(page);
81out:
82 return rc;
83}
84
85/**
Michael Halcrowe77a56d2007-02-12 00:53:47 -080086 * Header Extent:
87 * Octets 0-7: Unencrypted file size (big-endian)
88 * Octets 8-15: eCryptfs special marker
89 * Octets 16-19: Flags
90 * Octet 16: File format version number (between 0 and 255)
91 * Octets 17-18: Reserved
92 * Octet 19: Bit 1 (lsb): Reserved
93 * Bit 2: Encrypted?
94 * Bits 3-8: Reserved
95 * Octets 20-23: Header extent size (big-endian)
96 * Octets 24-25: Number of header extents at front of file
97 * (big-endian)
98 * Octet 26: Begin RFC 2440 authentication token packet set
99 */
100static void set_header_info(char *page_virt,
101 struct ecryptfs_crypt_stat *crypt_stat)
102{
103 size_t written;
Michael Halcrowcc11bef2008-02-06 01:38:32 -0800104 size_t save_num_header_bytes_at_front =
105 crypt_stat->num_header_bytes_at_front;
Michael Halcrowe77a56d2007-02-12 00:53:47 -0800106
Michael Halcrowcc11bef2008-02-06 01:38:32 -0800107 crypt_stat->num_header_bytes_at_front =
108 ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
Michael Halcrowe77a56d2007-02-12 00:53:47 -0800109 ecryptfs_write_header_metadata(page_virt + 20, crypt_stat, &written);
Michael Halcrowcc11bef2008-02-06 01:38:32 -0800110 crypt_stat->num_header_bytes_at_front =
111 save_num_header_bytes_at_front;
Michael Halcrowe77a56d2007-02-12 00:53:47 -0800112}
Michael Halcrow237fead2006-10-04 02:16:22 -0700113
114/**
Michael Halcrowbf12be12007-10-16 01:28:11 -0700115 * ecryptfs_copy_up_encrypted_with_header
116 * @page: Sort of a ``virtual'' representation of the encrypted lower
117 * file. The actual lower file does not have the metadata in
118 * the header. This is locked.
119 * @crypt_stat: The eCryptfs inode's cryptographic context
120 *
121 * The ``view'' is the version of the file that userspace winds up
122 * seeing, with the header information inserted.
123 */
124static int
125ecryptfs_copy_up_encrypted_with_header(struct page *page,
126 struct ecryptfs_crypt_stat *crypt_stat)
127{
128 loff_t extent_num_in_page = 0;
129 loff_t num_extents_per_page = (PAGE_CACHE_SIZE
130 / crypt_stat->extent_size);
131 int rc = 0;
132
133 while (extent_num_in_page < num_extents_per_page) {
Michael Halcrowd6a13c12007-10-16 01:28:12 -0700134 loff_t view_extent_num = ((((loff_t)page->index)
135 * num_extents_per_page)
Michael Halcrowbf12be12007-10-16 01:28:11 -0700136 + extent_num_in_page);
Michael Halcrowcc11bef2008-02-06 01:38:32 -0800137 size_t num_header_extents_at_front =
138 (crypt_stat->num_header_bytes_at_front
139 / crypt_stat->extent_size);
Michael Halcrowbf12be12007-10-16 01:28:11 -0700140
Michael Halcrowcc11bef2008-02-06 01:38:32 -0800141 if (view_extent_num < num_header_extents_at_front) {
Michael Halcrowbf12be12007-10-16 01:28:11 -0700142 /* This is a header extent */
143 char *page_virt;
144
145 page_virt = kmap_atomic(page, KM_USER0);
146 memset(page_virt, 0, PAGE_CACHE_SIZE);
147 /* TODO: Support more than one header extent */
148 if (view_extent_num == 0) {
149 rc = ecryptfs_read_xattr_region(
150 page_virt, page->mapping->host);
151 set_header_info(page_virt, crypt_stat);
152 }
153 kunmap_atomic(page_virt, KM_USER0);
154 flush_dcache_page(page);
155 if (rc) {
Michael Halcrowbf12be12007-10-16 01:28:11 -0700156 printk(KERN_ERR "%s: Error reading xattr "
Harvey Harrison18d1dbf2008-04-29 00:59:48 -0700157 "region; rc = [%d]\n", __func__, rc);
Michael Halcrowbf12be12007-10-16 01:28:11 -0700158 goto out;
159 }
Michael Halcrowbf12be12007-10-16 01:28:11 -0700160 } else {
161 /* This is an encrypted data extent */
162 loff_t lower_offset =
Michael Halcrowcc11bef2008-02-06 01:38:32 -0800163 ((view_extent_num * crypt_stat->extent_size)
164 - crypt_stat->num_header_bytes_at_front);
Michael Halcrowbf12be12007-10-16 01:28:11 -0700165
166 rc = ecryptfs_read_lower_page_segment(
167 page, (lower_offset >> PAGE_CACHE_SHIFT),
168 (lower_offset & ~PAGE_CACHE_MASK),
169 crypt_stat->extent_size, page->mapping->host);
170 if (rc) {
171 printk(KERN_ERR "%s: Error attempting to read "
172 "extent at offset [%lld] in the lower "
Harvey Harrison18d1dbf2008-04-29 00:59:48 -0700173 "file; rc = [%d]\n", __func__,
Michael Halcrowbf12be12007-10-16 01:28:11 -0700174 lower_offset, rc);
175 goto out;
176 }
177 }
178 extent_num_in_page++;
179 }
180out:
181 return rc;
182}
183
184/**
Michael Halcrow237fead2006-10-04 02:16:22 -0700185 * ecryptfs_readpage
Michael Halcrowbf12be12007-10-16 01:28:11 -0700186 * @file: An eCryptfs file
187 * @page: Page from eCryptfs inode mapping into which to stick the read data
Michael Halcrow237fead2006-10-04 02:16:22 -0700188 *
189 * Read in a page, decrypting if necessary.
190 *
191 * Returns zero on success; non-zero on error.
192 */
193static int ecryptfs_readpage(struct file *file, struct page *page)
194{
Michael Halcrowbf12be12007-10-16 01:28:11 -0700195 struct ecryptfs_crypt_stat *crypt_stat =
196 &ecryptfs_inode_to_private(file->f_path.dentry->d_inode)->crypt_stat;
Michael Halcrow237fead2006-10-04 02:16:22 -0700197 int rc = 0;
Michael Halcrow237fead2006-10-04 02:16:22 -0700198
Michael Halcrow237fead2006-10-04 02:16:22 -0700199 if (!crypt_stat
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800200 || !(crypt_stat->flags & ECRYPTFS_ENCRYPTED)
201 || (crypt_stat->flags & ECRYPTFS_NEW_FILE)) {
Michael Halcrow237fead2006-10-04 02:16:22 -0700202 ecryptfs_printk(KERN_DEBUG,
203 "Passing through unencrypted page\n");
Michael Halcrowbf12be12007-10-16 01:28:11 -0700204 rc = ecryptfs_read_lower_page_segment(page, page->index, 0,
205 PAGE_CACHE_SIZE,
206 page->mapping->host);
Michael Halcrowe77a56d2007-02-12 00:53:47 -0800207 } else if (crypt_stat->flags & ECRYPTFS_VIEW_AS_ENCRYPTED) {
208 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR) {
Michael Halcrowbf12be12007-10-16 01:28:11 -0700209 rc = ecryptfs_copy_up_encrypted_with_header(page,
210 crypt_stat);
211 if (rc) {
212 printk(KERN_ERR "%s: Error attempting to copy "
213 "the encrypted content from the lower "
214 "file whilst inserting the metadata "
215 "from the xattr into the header; rc = "
Harvey Harrison18d1dbf2008-04-29 00:59:48 -0700216 "[%d]\n", __func__, rc);
Michael Halcrowbf12be12007-10-16 01:28:11 -0700217 goto out;
Michael Halcrowe77a56d2007-02-12 00:53:47 -0800218 }
Michael Halcrowbf12be12007-10-16 01:28:11 -0700219
Michael Halcrowe77a56d2007-02-12 00:53:47 -0800220 } else {
Michael Halcrowbf12be12007-10-16 01:28:11 -0700221 rc = ecryptfs_read_lower_page_segment(
222 page, page->index, 0, PAGE_CACHE_SIZE,
223 page->mapping->host);
Michael Halcrowe77a56d2007-02-12 00:53:47 -0800224 if (rc) {
225 printk(KERN_ERR "Error reading page; rc = "
226 "[%d]\n", rc);
227 goto out;
228 }
229 }
Michael Halcrow237fead2006-10-04 02:16:22 -0700230 } else {
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700231 rc = ecryptfs_decrypt_page(page);
Michael Halcrow237fead2006-10-04 02:16:22 -0700232 if (rc) {
Michael Halcrow237fead2006-10-04 02:16:22 -0700233 ecryptfs_printk(KERN_ERR, "Error decrypting page; "
234 "rc = [%d]\n", rc);
235 goto out;
236 }
237 }
Michael Halcrow237fead2006-10-04 02:16:22 -0700238out:
Michael Halcrow16a72c42007-10-16 01:28:14 -0700239 if (rc)
240 ClearPageUptodate(page);
241 else
242 SetPageUptodate(page);
Michael Halcrow237fead2006-10-04 02:16:22 -0700243 ecryptfs_printk(KERN_DEBUG, "Unlocking page with index = [0x%.16x]\n",
244 page->index);
245 unlock_page(page);
246 return rc;
247}
248
Michael Halcrowdd2a3b72007-02-12 00:53:46 -0800249/**
250 * Called with lower inode mutex held.
251 */
Michael Halcrow237fead2006-10-04 02:16:22 -0700252static int fill_zeros_to_end_of_page(struct page *page, unsigned int to)
253{
254 struct inode *inode = page->mapping->host;
255 int end_byte_in_page;
Michael Halcrow237fead2006-10-04 02:16:22 -0700256
Michael Halcrow9d8b8ce2007-02-12 00:53:48 -0800257 if ((i_size_read(inode) / PAGE_CACHE_SIZE) != page->index)
258 goto out;
259 end_byte_in_page = i_size_read(inode) % PAGE_CACHE_SIZE;
260 if (to > end_byte_in_page)
261 end_byte_in_page = to;
Christoph Lametereebd2aa2008-02-04 22:28:29 -0800262 zero_user_segment(page, end_byte_in_page, PAGE_CACHE_SIZE);
Michael Halcrow237fead2006-10-04 02:16:22 -0700263out:
Michael Halcrow9d8b8ce2007-02-12 00:53:48 -0800264 return 0;
Michael Halcrow237fead2006-10-04 02:16:22 -0700265}
266
Michael Halcrowe4465fd2008-03-04 14:29:24 -0800267/**
Badari Pulavarty807b7eb2008-10-15 22:02:50 -0700268 * ecryptfs_write_begin
Michael Halcrowe4465fd2008-03-04 14:29:24 -0800269 * @file: The eCryptfs file
Badari Pulavarty807b7eb2008-10-15 22:02:50 -0700270 * @mapping: The eCryptfs object
271 * @pos: The file offset at which to start writing
272 * @len: Length of the write
273 * @flags: Various flags
274 * @pagep: Pointer to return the page
275 * @fsdata: Pointer to return fs data (unused)
Michael Halcrowe4465fd2008-03-04 14:29:24 -0800276 *
277 * This function must zero any hole we create
278 *
279 * Returns zero on success; non-zero otherwise
280 */
Badari Pulavarty807b7eb2008-10-15 22:02:50 -0700281static int ecryptfs_write_begin(struct file *file,
282 struct address_space *mapping,
283 loff_t pos, unsigned len, unsigned flags,
284 struct page **pagep, void **fsdata)
Michael Halcrow53a27312007-05-23 13:58:15 -0700285{
Badari Pulavarty807b7eb2008-10-15 22:02:50 -0700286 pgoff_t index = pos >> PAGE_CACHE_SHIFT;
287 struct page *page;
Eric Sandeen7a3f5952007-12-17 16:20:10 -0800288 loff_t prev_page_end_size;
Michael Halcrowe4465fd2008-03-04 14:29:24 -0800289 int rc = 0;
Michael Halcrow53a27312007-05-23 13:58:15 -0700290
Badari Pulavarty807b7eb2008-10-15 22:02:50 -0700291 page = __grab_cache_page(mapping, index);
292 if (!page)
293 return -ENOMEM;
294 *pagep = page;
295
Michael Halcrow16a72c42007-10-16 01:28:14 -0700296 if (!PageUptodate(page)) {
Michael Halcrowe4465fd2008-03-04 14:29:24 -0800297 struct ecryptfs_crypt_stat *crypt_stat =
298 &ecryptfs_inode_to_private(
299 file->f_path.dentry->d_inode)->crypt_stat;
300
301 if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)
302 || (crypt_stat->flags & ECRYPTFS_NEW_FILE)) {
303 rc = ecryptfs_read_lower_page_segment(
Badari Pulavarty807b7eb2008-10-15 22:02:50 -0700304 page, index, 0, PAGE_CACHE_SIZE, mapping->host);
Michael Halcrowe4465fd2008-03-04 14:29:24 -0800305 if (rc) {
306 printk(KERN_ERR "%s: Error attemping to read "
307 "lower page segment; rc = [%d]\n",
Harvey Harrison18d1dbf2008-04-29 00:59:48 -0700308 __func__, rc);
Michael Halcrowe4465fd2008-03-04 14:29:24 -0800309 ClearPageUptodate(page);
310 goto out;
311 } else
312 SetPageUptodate(page);
313 } else if (crypt_stat->flags & ECRYPTFS_VIEW_AS_ENCRYPTED) {
314 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR) {
315 rc = ecryptfs_copy_up_encrypted_with_header(
316 page, crypt_stat);
317 if (rc) {
318 printk(KERN_ERR "%s: Error attempting "
319 "to copy the encrypted content "
320 "from the lower file whilst "
321 "inserting the metadata from "
322 "the xattr into the header; rc "
Harvey Harrison18d1dbf2008-04-29 00:59:48 -0700323 "= [%d]\n", __func__, rc);
Michael Halcrowe4465fd2008-03-04 14:29:24 -0800324 ClearPageUptodate(page);
325 goto out;
326 }
327 SetPageUptodate(page);
328 } else {
329 rc = ecryptfs_read_lower_page_segment(
Badari Pulavarty807b7eb2008-10-15 22:02:50 -0700330 page, index, 0, PAGE_CACHE_SIZE,
331 mapping->host);
Michael Halcrowe4465fd2008-03-04 14:29:24 -0800332 if (rc) {
333 printk(KERN_ERR "%s: Error reading "
334 "page; rc = [%d]\n",
Harvey Harrison18d1dbf2008-04-29 00:59:48 -0700335 __func__, rc);
Michael Halcrowe4465fd2008-03-04 14:29:24 -0800336 ClearPageUptodate(page);
337 goto out;
338 }
339 SetPageUptodate(page);
340 }
341 } else {
342 rc = ecryptfs_decrypt_page(page);
343 if (rc) {
344 printk(KERN_ERR "%s: Error decrypting page "
345 "at index [%ld]; rc = [%d]\n",
Harvey Harrison18d1dbf2008-04-29 00:59:48 -0700346 __func__, page->index, rc);
Michael Halcrowe4465fd2008-03-04 14:29:24 -0800347 ClearPageUptodate(page);
348 goto out;
349 }
Michael Halcrow16a72c42007-10-16 01:28:14 -0700350 SetPageUptodate(page);
Michael Halcrowe4465fd2008-03-04 14:29:24 -0800351 }
Michael Halcrow16a72c42007-10-16 01:28:14 -0700352 }
Badari Pulavarty807b7eb2008-10-15 22:02:50 -0700353 prev_page_end_size = ((loff_t)index << PAGE_CACHE_SHIFT);
Michael Halcrowe4465fd2008-03-04 14:29:24 -0800354 /* If creating a page or more of holes, zero them out via truncate.
355 * Note, this will increase i_size. */
Badari Pulavarty807b7eb2008-10-15 22:02:50 -0700356 if (index != 0) {
Eric Sandeen7a3f5952007-12-17 16:20:10 -0800357 if (prev_page_end_size > i_size_read(page->mapping->host)) {
Michael Halcrow240e2df2007-06-27 14:09:44 -0700358 rc = ecryptfs_truncate(file->f_path.dentry,
Eric Sandeen7a3f5952007-12-17 16:20:10 -0800359 prev_page_end_size);
Michael Halcrow240e2df2007-06-27 14:09:44 -0700360 if (rc) {
Michael Halcrowe4465fd2008-03-04 14:29:24 -0800361 printk(KERN_ERR "%s: Error on attempt to "
Michael Halcrow240e2df2007-06-27 14:09:44 -0700362 "truncate to (higher) offset [%lld];"
Harvey Harrison18d1dbf2008-04-29 00:59:48 -0700363 " rc = [%d]\n", __func__,
Michael Halcrowe4465fd2008-03-04 14:29:24 -0800364 prev_page_end_size, rc);
Michael Halcrow240e2df2007-06-27 14:09:44 -0700365 goto out;
366 }
Michael Halcrow53a27312007-05-23 13:58:15 -0700367 }
Eric Sandeen7a3f5952007-12-17 16:20:10 -0800368 }
Michael Halcrowe4465fd2008-03-04 14:29:24 -0800369 /* Writing to a new page, and creating a small hole from start
370 * of page? Zero it out. */
Badari Pulavarty807b7eb2008-10-15 22:02:50 -0700371 if ((i_size_read(mapping->host) == prev_page_end_size)
372 && (pos != 0))
Christoph Lametereebd2aa2008-02-04 22:28:29 -0800373 zero_user(page, 0, PAGE_CACHE_SIZE);
Michael Halcrow53a27312007-05-23 13:58:15 -0700374out:
375 return rc;
376}
377
Michael Halcrow237fead2006-10-04 02:16:22 -0700378/**
379 * ecryptfs_write_inode_size_to_header
380 *
381 * Writes the lower file size to the first 8 bytes of the header.
382 *
383 * Returns zero on success; non-zero on error.
384 */
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700385static int ecryptfs_write_inode_size_to_header(struct inode *ecryptfs_inode)
Michael Halcrow237fead2006-10-04 02:16:22 -0700386{
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700387 char *file_size_virt;
388 int rc;
Michael Halcrow237fead2006-10-04 02:16:22 -0700389
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700390 file_size_virt = kmalloc(sizeof(u64), GFP_KERNEL);
391 if (!file_size_virt) {
392 rc = -ENOMEM;
Michael Halcrow237fead2006-10-04 02:16:22 -0700393 goto out;
394 }
Harvey Harrison0a688ad2008-07-23 21:30:07 -0700395 put_unaligned_be64(i_size_read(ecryptfs_inode), file_size_virt);
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700396 rc = ecryptfs_write_lower(ecryptfs_inode, file_size_virt, 0,
397 sizeof(u64));
398 kfree(file_size_virt);
399 if (rc)
400 printk(KERN_ERR "%s: Error writing file size to header; "
Harvey Harrison18d1dbf2008-04-29 00:59:48 -0700401 "rc = [%d]\n", __func__, rc);
Michael Halcrow237fead2006-10-04 02:16:22 -0700402out:
403 return rc;
404}
405
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700406struct kmem_cache *ecryptfs_xattr_cache;
407
408static int ecryptfs_write_inode_size_to_xattr(struct inode *ecryptfs_inode)
Michael Halcrowdd2a3b72007-02-12 00:53:46 -0800409{
410 ssize_t size;
411 void *xattr_virt;
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700412 struct dentry *lower_dentry =
413 ecryptfs_inode_to_private(ecryptfs_inode)->lower_file->f_dentry;
414 struct inode *lower_inode = lower_dentry->d_inode;
Michael Halcrowdd2a3b72007-02-12 00:53:46 -0800415 int rc;
416
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700417 if (!lower_inode->i_op->getxattr || !lower_inode->i_op->setxattr) {
418 printk(KERN_WARNING
419 "No support for setting xattr in lower filesystem\n");
420 rc = -ENOSYS;
421 goto out;
422 }
Michael Halcrowdd2a3b72007-02-12 00:53:46 -0800423 xattr_virt = kmem_cache_alloc(ecryptfs_xattr_cache, GFP_KERNEL);
424 if (!xattr_virt) {
425 printk(KERN_ERR "Out of memory whilst attempting to write "
426 "inode size to xattr\n");
427 rc = -ENOMEM;
428 goto out;
429 }
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700430 mutex_lock(&lower_inode->i_mutex);
431 size = lower_inode->i_op->getxattr(lower_dentry, ECRYPTFS_XATTR_NAME,
432 xattr_virt, PAGE_CACHE_SIZE);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -0800433 if (size < 0)
434 size = 8;
Harvey Harrison0a688ad2008-07-23 21:30:07 -0700435 put_unaligned_be64(i_size_read(ecryptfs_inode), xattr_virt);
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700436 rc = lower_inode->i_op->setxattr(lower_dentry, ECRYPTFS_XATTR_NAME,
437 xattr_virt, size, 0);
438 mutex_unlock(&lower_inode->i_mutex);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -0800439 if (rc)
440 printk(KERN_ERR "Error whilst attempting to write inode size "
441 "to lower file xattr; rc = [%d]\n", rc);
442 kmem_cache_free(ecryptfs_xattr_cache, xattr_virt);
443out:
444 return rc;
445}
446
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700447int ecryptfs_write_inode_size_to_metadata(struct inode *ecryptfs_inode)
Michael Halcrowdd2a3b72007-02-12 00:53:46 -0800448{
449 struct ecryptfs_crypt_stat *crypt_stat;
450
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700451 crypt_stat = &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
Michael Halcrowdd2a3b72007-02-12 00:53:46 -0800452 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700453 return ecryptfs_write_inode_size_to_xattr(ecryptfs_inode);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -0800454 else
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700455 return ecryptfs_write_inode_size_to_header(ecryptfs_inode);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -0800456}
457
Michael Halcrow237fead2006-10-04 02:16:22 -0700458/**
Badari Pulavarty807b7eb2008-10-15 22:02:50 -0700459 * ecryptfs_write_end
Michael Halcrow237fead2006-10-04 02:16:22 -0700460 * @file: The eCryptfs file object
Badari Pulavarty807b7eb2008-10-15 22:02:50 -0700461 * @mapping: The eCryptfs object
462 * @pos: The file position
463 * @len: The length of the data (unused)
464 * @copied: The amount of data copied
Michael Halcrow237fead2006-10-04 02:16:22 -0700465 * @page: The eCryptfs page
Badari Pulavarty807b7eb2008-10-15 22:02:50 -0700466 * @fsdata: The fsdata (unused)
Michael Halcrow237fead2006-10-04 02:16:22 -0700467 *
468 * This is where we encrypt the data and pass the encrypted data to
469 * the lower filesystem. In OpenPGP-compatible mode, we operate on
470 * entire underlying packets.
471 */
Badari Pulavarty807b7eb2008-10-15 22:02:50 -0700472static int ecryptfs_write_end(struct file *file,
473 struct address_space *mapping,
474 loff_t pos, unsigned len, unsigned copied,
475 struct page *page, void *fsdata)
Michael Halcrow237fead2006-10-04 02:16:22 -0700476{
Badari Pulavarty807b7eb2008-10-15 22:02:50 -0700477 pgoff_t index = pos >> PAGE_CACHE_SHIFT;
478 unsigned from = pos & (PAGE_CACHE_SIZE - 1);
479 unsigned to = from + copied;
480 struct inode *ecryptfs_inode = mapping->host;
Michael Halcrowbf12be12007-10-16 01:28:11 -0700481 struct ecryptfs_crypt_stat *crypt_stat =
482 &ecryptfs_inode_to_private(file->f_path.dentry->d_inode)->crypt_stat;
Michael Halcrow237fead2006-10-04 02:16:22 -0700483 int rc;
484
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800485 if (crypt_stat->flags & ECRYPTFS_NEW_FILE) {
Michael Halcrow237fead2006-10-04 02:16:22 -0700486 ecryptfs_printk(KERN_DEBUG, "ECRYPTFS_NEW_FILE flag set in "
487 "crypt_stat at memory location [%p]\n", crypt_stat);
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800488 crypt_stat->flags &= ~(ECRYPTFS_NEW_FILE);
Michael Halcrow237fead2006-10-04 02:16:22 -0700489 } else
490 ecryptfs_printk(KERN_DEBUG, "Not a new file\n");
491 ecryptfs_printk(KERN_DEBUG, "Calling fill_zeros_to_end_of_page"
Badari Pulavarty807b7eb2008-10-15 22:02:50 -0700492 "(page w/ index = [0x%.16x], to = [%d])\n", index, to);
Michael Halcrowbf12be12007-10-16 01:28:11 -0700493 /* Fills in zeros if 'to' goes beyond inode size */
Michael Halcrow237fead2006-10-04 02:16:22 -0700494 rc = fill_zeros_to_end_of_page(page, to);
495 if (rc) {
496 ecryptfs_printk(KERN_WARNING, "Error attempting to fill "
Badari Pulavarty807b7eb2008-10-15 22:02:50 -0700497 "zeros in page with index = [0x%.16x]\n", index);
Michael Halcrow237fead2006-10-04 02:16:22 -0700498 goto out;
499 }
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700500 rc = ecryptfs_encrypt_page(page);
Michael Halcrow237fead2006-10-04 02:16:22 -0700501 if (rc) {
502 ecryptfs_printk(KERN_WARNING, "Error encrypting page (upper "
Badari Pulavarty807b7eb2008-10-15 22:02:50 -0700503 "index [0x%.16x])\n", index);
Michael Halcrow237fead2006-10-04 02:16:22 -0700504 goto out;
505 }
Badari Pulavarty807b7eb2008-10-15 22:02:50 -0700506 if (pos + copied > i_size_read(ecryptfs_inode)) {
507 i_size_write(ecryptfs_inode, pos + copied);
Michael Halcrow237fead2006-10-04 02:16:22 -0700508 ecryptfs_printk(KERN_DEBUG, "Expanded file size to "
Michael Halcrowbf12be12007-10-16 01:28:11 -0700509 "[0x%.16x]\n", i_size_read(ecryptfs_inode));
Michael Halcrow237fead2006-10-04 02:16:22 -0700510 }
Michael Halcrowbf12be12007-10-16 01:28:11 -0700511 rc = ecryptfs_write_inode_size_to_metadata(ecryptfs_inode);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -0800512 if (rc)
513 printk(KERN_ERR "Error writing inode size to metadata; "
514 "rc = [%d]\n", rc);
Badari Pulavarty807b7eb2008-10-15 22:02:50 -0700515 else
516 rc = copied;
Michael Halcrow237fead2006-10-04 02:16:22 -0700517out:
Badari Pulavarty807b7eb2008-10-15 22:02:50 -0700518 unlock_page(page);
519 page_cache_release(page);
Michael Halcrow237fead2006-10-04 02:16:22 -0700520 return rc;
521}
522
Michael Halcrow237fead2006-10-04 02:16:22 -0700523static sector_t ecryptfs_bmap(struct address_space *mapping, sector_t block)
524{
525 int rc = 0;
526 struct inode *inode;
527 struct inode *lower_inode;
528
529 inode = (struct inode *)mapping->host;
530 lower_inode = ecryptfs_inode_to_lower(inode);
531 if (lower_inode->i_mapping->a_ops->bmap)
532 rc = lower_inode->i_mapping->a_ops->bmap(lower_inode->i_mapping,
533 block);
534 return rc;
535}
536
Michael Halcrow237fead2006-10-04 02:16:22 -0700537struct address_space_operations ecryptfs_aops = {
538 .writepage = ecryptfs_writepage,
539 .readpage = ecryptfs_readpage,
Badari Pulavarty807b7eb2008-10-15 22:02:50 -0700540 .write_begin = ecryptfs_write_begin,
541 .write_end = ecryptfs_write_end,
Michael Halcrow237fead2006-10-04 02:16:22 -0700542 .bmap = ecryptfs_bmap,
Michael Halcrow237fead2006-10-04 02:16:22 -0700543};