blob: cc64fca89f8dc995f8ca5af82d135c053c6d59b2 [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>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090035#include <linux/slab.h>
Harvey Harrison0a688ad2008-07-23 21:30:07 -070036#include <asm/unaligned.h>
Michael Halcrow237fead2006-10-04 02:16:22 -070037#include "ecryptfs_kernel.h"
38
Michael Halcrow237fead2006-10-04 02:16:22 -070039/**
Michael Halcrow16a72c42007-10-16 01:28:14 -070040 * ecryptfs_get_locked_page
Michael Halcrow237fead2006-10-04 02:16:22 -070041 *
42 * Get one page from cache or lower f/s, return error otherwise.
43 *
Michael Halcrow16a72c42007-10-16 01:28:14 -070044 * Returns locked and up-to-date page (if ok), with increased
Michael Halcrow237fead2006-10-04 02:16:22 -070045 * refcnt.
46 */
Al Viro02bd9792010-05-21 11:02:14 -040047struct page *ecryptfs_get_locked_page(struct inode *inode, loff_t index)
Michael Halcrow237fead2006-10-04 02:16:22 -070048{
Al Viro02bd9792010-05-21 11:02:14 -040049 struct page *page = read_mapping_page(inode->i_mapping, index, NULL);
Michael Halcrow16a72c42007-10-16 01:28:14 -070050 if (!IS_ERR(page))
51 lock_page(page);
52 return page;
Michael Halcrow237fead2006-10-04 02:16:22 -070053}
54
Michael Halcrow237fead2006-10-04 02:16:22 -070055/**
Michael Halcrow237fead2006-10-04 02:16:22 -070056 * ecryptfs_writepage
57 * @page: Page that is locked before this call is made
58 *
59 * Returns zero on success; non-zero otherwise
60 */
61static int ecryptfs_writepage(struct page *page, struct writeback_control *wbc)
62{
Michael Halcrow237fead2006-10-04 02:16:22 -070063 int rc;
64
Michael Halcrow0216f7f2007-10-16 01:28:08 -070065 rc = ecryptfs_encrypt_page(page);
Michael Halcrow237fead2006-10-04 02:16:22 -070066 if (rc) {
67 ecryptfs_printk(KERN_WARNING, "Error encrypting "
Joe Perches888d57b2010-11-10 15:46:16 -080068 "page (upper index [0x%.16lx])\n", page->index);
Michael Halcrow237fead2006-10-04 02:16:22 -070069 ClearPageUptodate(page);
70 goto out;
71 }
72 SetPageUptodate(page);
73 unlock_page(page);
74out:
75 return rc;
76}
77
Tyler Hicksf4e60e62010-02-11 00:02:32 -060078static void strip_xattr_flag(char *page_virt,
79 struct ecryptfs_crypt_stat *crypt_stat)
80{
81 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR) {
82 size_t written;
83
84 crypt_stat->flags &= ~ECRYPTFS_METADATA_IN_XATTR;
85 ecryptfs_write_crypt_stat_flags(page_virt, crypt_stat,
86 &written);
87 crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
88 }
89}
90
Michael Halcrow237fead2006-10-04 02:16:22 -070091/**
Michael Halcrowe77a56d2007-02-12 00:53:47 -080092 * Header Extent:
93 * Octets 0-7: Unencrypted file size (big-endian)
94 * Octets 8-15: eCryptfs special marker
95 * Octets 16-19: Flags
96 * Octet 16: File format version number (between 0 and 255)
97 * Octets 17-18: Reserved
98 * Octet 19: Bit 1 (lsb): Reserved
99 * Bit 2: Encrypted?
100 * Bits 3-8: Reserved
101 * Octets 20-23: Header extent size (big-endian)
102 * Octets 24-25: Number of header extents at front of file
103 * (big-endian)
104 * Octet 26: Begin RFC 2440 authentication token packet set
105 */
Michael Halcrow237fead2006-10-04 02:16:22 -0700106
107/**
Michael Halcrowbf12be12007-10-16 01:28:11 -0700108 * ecryptfs_copy_up_encrypted_with_header
109 * @page: Sort of a ``virtual'' representation of the encrypted lower
110 * file. The actual lower file does not have the metadata in
111 * the header. This is locked.
112 * @crypt_stat: The eCryptfs inode's cryptographic context
113 *
114 * The ``view'' is the version of the file that userspace winds up
115 * seeing, with the header information inserted.
116 */
117static int
118ecryptfs_copy_up_encrypted_with_header(struct page *page,
119 struct ecryptfs_crypt_stat *crypt_stat)
120{
121 loff_t extent_num_in_page = 0;
122 loff_t num_extents_per_page = (PAGE_CACHE_SIZE
123 / crypt_stat->extent_size);
124 int rc = 0;
125
126 while (extent_num_in_page < num_extents_per_page) {
Michael Halcrowd6a13c12007-10-16 01:28:12 -0700127 loff_t view_extent_num = ((((loff_t)page->index)
128 * num_extents_per_page)
Michael Halcrowbf12be12007-10-16 01:28:11 -0700129 + extent_num_in_page);
Michael Halcrowcc11bef2008-02-06 01:38:32 -0800130 size_t num_header_extents_at_front =
Tyler Hicksfa3ef1c2010-02-11 05:09:14 -0600131 (crypt_stat->metadata_size / crypt_stat->extent_size);
Michael Halcrowbf12be12007-10-16 01:28:11 -0700132
Michael Halcrowcc11bef2008-02-06 01:38:32 -0800133 if (view_extent_num < num_header_extents_at_front) {
Michael Halcrowbf12be12007-10-16 01:28:11 -0700134 /* This is a header extent */
135 char *page_virt;
136
137 page_virt = kmap_atomic(page, KM_USER0);
138 memset(page_virt, 0, PAGE_CACHE_SIZE);
139 /* TODO: Support more than one header extent */
140 if (view_extent_num == 0) {
Tyler Hicks157f1072010-02-11 07:10:38 -0600141 size_t written;
142
Michael Halcrowbf12be12007-10-16 01:28:11 -0700143 rc = ecryptfs_read_xattr_region(
144 page_virt, page->mapping->host);
Tyler Hicksf4e60e62010-02-11 00:02:32 -0600145 strip_xattr_flag(page_virt + 16, crypt_stat);
Tyler Hicks157f1072010-02-11 07:10:38 -0600146 ecryptfs_write_header_metadata(page_virt + 20,
147 crypt_stat,
148 &written);
Michael Halcrowbf12be12007-10-16 01:28:11 -0700149 }
150 kunmap_atomic(page_virt, KM_USER0);
151 flush_dcache_page(page);
152 if (rc) {
Michael Halcrowbf12be12007-10-16 01:28:11 -0700153 printk(KERN_ERR "%s: Error reading xattr "
Harvey Harrison18d1dbf2008-04-29 00:59:48 -0700154 "region; rc = [%d]\n", __func__, rc);
Michael Halcrowbf12be12007-10-16 01:28:11 -0700155 goto out;
156 }
Michael Halcrowbf12be12007-10-16 01:28:11 -0700157 } else {
158 /* This is an encrypted data extent */
159 loff_t lower_offset =
Michael Halcrowcc11bef2008-02-06 01:38:32 -0800160 ((view_extent_num * crypt_stat->extent_size)
Tyler Hicksfa3ef1c2010-02-11 05:09:14 -0600161 - crypt_stat->metadata_size);
Michael Halcrowbf12be12007-10-16 01:28:11 -0700162
163 rc = ecryptfs_read_lower_page_segment(
164 page, (lower_offset >> PAGE_CACHE_SHIFT),
165 (lower_offset & ~PAGE_CACHE_MASK),
166 crypt_stat->extent_size, page->mapping->host);
167 if (rc) {
168 printk(KERN_ERR "%s: Error attempting to read "
169 "extent at offset [%lld] in the lower "
Harvey Harrison18d1dbf2008-04-29 00:59:48 -0700170 "file; rc = [%d]\n", __func__,
Michael Halcrowbf12be12007-10-16 01:28:11 -0700171 lower_offset, rc);
172 goto out;
173 }
174 }
175 extent_num_in_page++;
176 }
177out:
178 return rc;
179}
180
181/**
Michael Halcrow237fead2006-10-04 02:16:22 -0700182 * ecryptfs_readpage
Michael Halcrowbf12be12007-10-16 01:28:11 -0700183 * @file: An eCryptfs file
184 * @page: Page from eCryptfs inode mapping into which to stick the read data
Michael Halcrow237fead2006-10-04 02:16:22 -0700185 *
186 * Read in a page, decrypting if necessary.
187 *
188 * Returns zero on success; non-zero on error.
189 */
190static int ecryptfs_readpage(struct file *file, struct page *page)
191{
Michael Halcrowbf12be12007-10-16 01:28:11 -0700192 struct ecryptfs_crypt_stat *crypt_stat =
Al Virobef5bc22010-05-21 10:56:12 -0400193 &ecryptfs_inode_to_private(page->mapping->host)->crypt_stat;
Michael Halcrow237fead2006-10-04 02:16:22 -0700194 int rc = 0;
Michael Halcrow237fead2006-10-04 02:16:22 -0700195
Michael Halcrow237fead2006-10-04 02:16:22 -0700196 if (!crypt_stat
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800197 || !(crypt_stat->flags & ECRYPTFS_ENCRYPTED)
198 || (crypt_stat->flags & ECRYPTFS_NEW_FILE)) {
Michael Halcrow237fead2006-10-04 02:16:22 -0700199 ecryptfs_printk(KERN_DEBUG,
200 "Passing through unencrypted page\n");
Michael Halcrowbf12be12007-10-16 01:28:11 -0700201 rc = ecryptfs_read_lower_page_segment(page, page->index, 0,
202 PAGE_CACHE_SIZE,
203 page->mapping->host);
Michael Halcrowe77a56d2007-02-12 00:53:47 -0800204 } else if (crypt_stat->flags & ECRYPTFS_VIEW_AS_ENCRYPTED) {
205 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR) {
Michael Halcrowbf12be12007-10-16 01:28:11 -0700206 rc = ecryptfs_copy_up_encrypted_with_header(page,
207 crypt_stat);
208 if (rc) {
209 printk(KERN_ERR "%s: Error attempting to copy "
210 "the encrypted content from the lower "
211 "file whilst inserting the metadata "
212 "from the xattr into the header; rc = "
Harvey Harrison18d1dbf2008-04-29 00:59:48 -0700213 "[%d]\n", __func__, rc);
Michael Halcrowbf12be12007-10-16 01:28:11 -0700214 goto out;
Michael Halcrowe77a56d2007-02-12 00:53:47 -0800215 }
Michael Halcrowbf12be12007-10-16 01:28:11 -0700216
Michael Halcrowe77a56d2007-02-12 00:53:47 -0800217 } else {
Michael Halcrowbf12be12007-10-16 01:28:11 -0700218 rc = ecryptfs_read_lower_page_segment(
219 page, page->index, 0, PAGE_CACHE_SIZE,
220 page->mapping->host);
Michael Halcrowe77a56d2007-02-12 00:53:47 -0800221 if (rc) {
222 printk(KERN_ERR "Error reading page; rc = "
223 "[%d]\n", rc);
224 goto out;
225 }
226 }
Michael Halcrow237fead2006-10-04 02:16:22 -0700227 } else {
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700228 rc = ecryptfs_decrypt_page(page);
Michael Halcrow237fead2006-10-04 02:16:22 -0700229 if (rc) {
Michael Halcrow237fead2006-10-04 02:16:22 -0700230 ecryptfs_printk(KERN_ERR, "Error decrypting page; "
231 "rc = [%d]\n", rc);
232 goto out;
233 }
234 }
Michael Halcrow237fead2006-10-04 02:16:22 -0700235out:
Michael Halcrow16a72c42007-10-16 01:28:14 -0700236 if (rc)
237 ClearPageUptodate(page);
238 else
239 SetPageUptodate(page);
Joe Perches888d57b2010-11-10 15:46:16 -0800240 ecryptfs_printk(KERN_DEBUG, "Unlocking page with index = [0x%.16lx]\n",
Michael Halcrow237fead2006-10-04 02:16:22 -0700241 page->index);
242 unlock_page(page);
243 return rc;
244}
245
Michael Halcrowdd2a3b72007-02-12 00:53:46 -0800246/**
247 * Called with lower inode mutex held.
248 */
Michael Halcrow237fead2006-10-04 02:16:22 -0700249static int fill_zeros_to_end_of_page(struct page *page, unsigned int to)
250{
251 struct inode *inode = page->mapping->host;
252 int end_byte_in_page;
Michael Halcrow237fead2006-10-04 02:16:22 -0700253
Michael Halcrow9d8b8ce2007-02-12 00:53:48 -0800254 if ((i_size_read(inode) / PAGE_CACHE_SIZE) != page->index)
255 goto out;
256 end_byte_in_page = i_size_read(inode) % PAGE_CACHE_SIZE;
257 if (to > end_byte_in_page)
258 end_byte_in_page = to;
Christoph Lametereebd2aa2008-02-04 22:28:29 -0800259 zero_user_segment(page, end_byte_in_page, PAGE_CACHE_SIZE);
Michael Halcrow237fead2006-10-04 02:16:22 -0700260out:
Michael Halcrow9d8b8ce2007-02-12 00:53:48 -0800261 return 0;
Michael Halcrow237fead2006-10-04 02:16:22 -0700262}
263
Michael Halcrowe4465fd2008-03-04 14:29:24 -0800264/**
Badari Pulavarty807b7eb2008-10-15 22:02:50 -0700265 * ecryptfs_write_begin
Michael Halcrowe4465fd2008-03-04 14:29:24 -0800266 * @file: The eCryptfs file
Badari Pulavarty807b7eb2008-10-15 22:02:50 -0700267 * @mapping: The eCryptfs object
268 * @pos: The file offset at which to start writing
269 * @len: Length of the write
270 * @flags: Various flags
271 * @pagep: Pointer to return the page
272 * @fsdata: Pointer to return fs data (unused)
Michael Halcrowe4465fd2008-03-04 14:29:24 -0800273 *
274 * This function must zero any hole we create
275 *
276 * Returns zero on success; non-zero otherwise
277 */
Badari Pulavarty807b7eb2008-10-15 22:02:50 -0700278static int ecryptfs_write_begin(struct file *file,
279 struct address_space *mapping,
280 loff_t pos, unsigned len, unsigned flags,
281 struct page **pagep, void **fsdata)
Michael Halcrow53a27312007-05-23 13:58:15 -0700282{
Badari Pulavarty807b7eb2008-10-15 22:02:50 -0700283 pgoff_t index = pos >> PAGE_CACHE_SHIFT;
284 struct page *page;
Eric Sandeen7a3f5952007-12-17 16:20:10 -0800285 loff_t prev_page_end_size;
Michael Halcrowe4465fd2008-03-04 14:29:24 -0800286 int rc = 0;
Michael Halcrow53a27312007-05-23 13:58:15 -0700287
Nick Piggin54566b22009-01-04 12:00:53 -0800288 page = grab_cache_page_write_begin(mapping, index, flags);
Badari Pulavarty807b7eb2008-10-15 22:02:50 -0700289 if (!page)
290 return -ENOMEM;
291 *pagep = page;
292
Frank Swiderski24562482010-11-15 10:43:22 -0800293 prev_page_end_size = ((loff_t)index << PAGE_CACHE_SHIFT);
Michael Halcrow16a72c42007-10-16 01:28:14 -0700294 if (!PageUptodate(page)) {
Michael Halcrowe4465fd2008-03-04 14:29:24 -0800295 struct ecryptfs_crypt_stat *crypt_stat =
Al Virobef5bc22010-05-21 10:56:12 -0400296 &ecryptfs_inode_to_private(mapping->host)->crypt_stat;
Michael Halcrowe4465fd2008-03-04 14:29:24 -0800297
298 if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)
299 || (crypt_stat->flags & ECRYPTFS_NEW_FILE)) {
300 rc = ecryptfs_read_lower_page_segment(
Badari Pulavarty807b7eb2008-10-15 22:02:50 -0700301 page, index, 0, PAGE_CACHE_SIZE, mapping->host);
Michael Halcrowe4465fd2008-03-04 14:29:24 -0800302 if (rc) {
303 printk(KERN_ERR "%s: Error attemping to read "
304 "lower page segment; rc = [%d]\n",
Harvey Harrison18d1dbf2008-04-29 00:59:48 -0700305 __func__, rc);
Michael Halcrowe4465fd2008-03-04 14:29:24 -0800306 ClearPageUptodate(page);
307 goto out;
308 } else
309 SetPageUptodate(page);
310 } else if (crypt_stat->flags & ECRYPTFS_VIEW_AS_ENCRYPTED) {
311 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR) {
312 rc = ecryptfs_copy_up_encrypted_with_header(
313 page, crypt_stat);
314 if (rc) {
315 printk(KERN_ERR "%s: Error attempting "
316 "to copy the encrypted content "
317 "from the lower file whilst "
318 "inserting the metadata from "
319 "the xattr into the header; rc "
Harvey Harrison18d1dbf2008-04-29 00:59:48 -0700320 "= [%d]\n", __func__, rc);
Michael Halcrowe4465fd2008-03-04 14:29:24 -0800321 ClearPageUptodate(page);
322 goto out;
323 }
324 SetPageUptodate(page);
325 } else {
326 rc = ecryptfs_read_lower_page_segment(
Badari Pulavarty807b7eb2008-10-15 22:02:50 -0700327 page, index, 0, PAGE_CACHE_SIZE,
328 mapping->host);
Michael Halcrowe4465fd2008-03-04 14:29:24 -0800329 if (rc) {
330 printk(KERN_ERR "%s: Error reading "
331 "page; rc = [%d]\n",
Harvey Harrison18d1dbf2008-04-29 00:59:48 -0700332 __func__, rc);
Michael Halcrowe4465fd2008-03-04 14:29:24 -0800333 ClearPageUptodate(page);
334 goto out;
335 }
336 SetPageUptodate(page);
337 }
338 } else {
Frank Swiderski24562482010-11-15 10:43:22 -0800339 if (prev_page_end_size
340 >= i_size_read(page->mapping->host)) {
341 zero_user(page, 0, PAGE_CACHE_SIZE);
342 } else {
343 rc = ecryptfs_decrypt_page(page);
344 if (rc) {
345 printk(KERN_ERR "%s: Error decrypting "
346 "page at index [%ld]; "
347 "rc = [%d]\n",
348 __func__, page->index, rc);
349 ClearPageUptodate(page);
350 goto out;
351 }
Michael Halcrowe4465fd2008-03-04 14:29:24 -0800352 }
Michael Halcrow16a72c42007-10-16 01:28:14 -0700353 SetPageUptodate(page);
Michael Halcrowe4465fd2008-03-04 14:29:24 -0800354 }
Michael Halcrow16a72c42007-10-16 01:28:14 -0700355 }
Michael Halcrowe4465fd2008-03-04 14:29:24 -0800356 /* If creating a page or more of holes, zero them out via truncate.
357 * Note, this will increase i_size. */
Badari Pulavarty807b7eb2008-10-15 22:02:50 -0700358 if (index != 0) {
Eric Sandeen7a3f5952007-12-17 16:20:10 -0800359 if (prev_page_end_size > i_size_read(page->mapping->host)) {
Michael Halcrow240e2df2007-06-27 14:09:44 -0700360 rc = ecryptfs_truncate(file->f_path.dentry,
Eric Sandeen7a3f5952007-12-17 16:20:10 -0800361 prev_page_end_size);
Michael Halcrow240e2df2007-06-27 14:09:44 -0700362 if (rc) {
Michael Halcrowe4465fd2008-03-04 14:29:24 -0800363 printk(KERN_ERR "%s: Error on attempt to "
Michael Halcrow240e2df2007-06-27 14:09:44 -0700364 "truncate to (higher) offset [%lld];"
Harvey Harrison18d1dbf2008-04-29 00:59:48 -0700365 " rc = [%d]\n", __func__,
Michael Halcrowe4465fd2008-03-04 14:29:24 -0800366 prev_page_end_size, rc);
Michael Halcrow240e2df2007-06-27 14:09:44 -0700367 goto out;
368 }
Michael Halcrow53a27312007-05-23 13:58:15 -0700369 }
Eric Sandeen7a3f5952007-12-17 16:20:10 -0800370 }
Michael Halcrowe4465fd2008-03-04 14:29:24 -0800371 /* Writing to a new page, and creating a small hole from start
372 * of page? Zero it out. */
Badari Pulavarty807b7eb2008-10-15 22:02:50 -0700373 if ((i_size_read(mapping->host) == prev_page_end_size)
374 && (pos != 0))
Christoph Lametereebd2aa2008-02-04 22:28:29 -0800375 zero_user(page, 0, PAGE_CACHE_SIZE);
Michael Halcrow53a27312007-05-23 13:58:15 -0700376out:
377 return rc;
378}
379
Michael Halcrow237fead2006-10-04 02:16:22 -0700380/**
381 * ecryptfs_write_inode_size_to_header
382 *
383 * Writes the lower file size to the first 8 bytes of the header.
384 *
385 * Returns zero on success; non-zero on error.
386 */
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700387static int ecryptfs_write_inode_size_to_header(struct inode *ecryptfs_inode)
Michael Halcrow237fead2006-10-04 02:16:22 -0700388{
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700389 char *file_size_virt;
390 int rc;
Michael Halcrow237fead2006-10-04 02:16:22 -0700391
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700392 file_size_virt = kmalloc(sizeof(u64), GFP_KERNEL);
393 if (!file_size_virt) {
394 rc = -ENOMEM;
Michael Halcrow237fead2006-10-04 02:16:22 -0700395 goto out;
396 }
Harvey Harrison0a688ad2008-07-23 21:30:07 -0700397 put_unaligned_be64(i_size_read(ecryptfs_inode), file_size_virt);
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700398 rc = ecryptfs_write_lower(ecryptfs_inode, file_size_virt, 0,
399 sizeof(u64));
400 kfree(file_size_virt);
Tyler Hicks96a7b9c2009-09-16 19:04:20 -0500401 if (rc < 0)
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700402 printk(KERN_ERR "%s: Error writing file size to header; "
Harvey Harrison18d1dbf2008-04-29 00:59:48 -0700403 "rc = [%d]\n", __func__, rc);
Tyler Hicks96a7b9c2009-09-16 19:04:20 -0500404 else
405 rc = 0;
Michael Halcrow237fead2006-10-04 02:16:22 -0700406out:
407 return rc;
408}
409
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700410struct kmem_cache *ecryptfs_xattr_cache;
411
412static int ecryptfs_write_inode_size_to_xattr(struct inode *ecryptfs_inode)
Michael Halcrowdd2a3b72007-02-12 00:53:46 -0800413{
414 ssize_t size;
415 void *xattr_virt;
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700416 struct dentry *lower_dentry =
417 ecryptfs_inode_to_private(ecryptfs_inode)->lower_file->f_dentry;
418 struct inode *lower_inode = lower_dentry->d_inode;
Michael Halcrowdd2a3b72007-02-12 00:53:46 -0800419 int rc;
420
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700421 if (!lower_inode->i_op->getxattr || !lower_inode->i_op->setxattr) {
422 printk(KERN_WARNING
423 "No support for setting xattr in lower filesystem\n");
424 rc = -ENOSYS;
425 goto out;
426 }
Michael Halcrowdd2a3b72007-02-12 00:53:46 -0800427 xattr_virt = kmem_cache_alloc(ecryptfs_xattr_cache, GFP_KERNEL);
428 if (!xattr_virt) {
429 printk(KERN_ERR "Out of memory whilst attempting to write "
430 "inode size to xattr\n");
431 rc = -ENOMEM;
432 goto out;
433 }
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700434 mutex_lock(&lower_inode->i_mutex);
435 size = lower_inode->i_op->getxattr(lower_dentry, ECRYPTFS_XATTR_NAME,
436 xattr_virt, PAGE_CACHE_SIZE);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -0800437 if (size < 0)
438 size = 8;
Harvey Harrison0a688ad2008-07-23 21:30:07 -0700439 put_unaligned_be64(i_size_read(ecryptfs_inode), xattr_virt);
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700440 rc = lower_inode->i_op->setxattr(lower_dentry, ECRYPTFS_XATTR_NAME,
441 xattr_virt, size, 0);
442 mutex_unlock(&lower_inode->i_mutex);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -0800443 if (rc)
444 printk(KERN_ERR "Error whilst attempting to write inode size "
445 "to lower file xattr; rc = [%d]\n", rc);
446 kmem_cache_free(ecryptfs_xattr_cache, xattr_virt);
447out:
448 return rc;
449}
450
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700451int ecryptfs_write_inode_size_to_metadata(struct inode *ecryptfs_inode)
Michael Halcrowdd2a3b72007-02-12 00:53:46 -0800452{
453 struct ecryptfs_crypt_stat *crypt_stat;
454
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700455 crypt_stat = &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
Tyler Hicks13a791b2009-04-13 15:29:27 -0500456 BUG_ON(!(crypt_stat->flags & ECRYPTFS_ENCRYPTED));
Michael Halcrowdd2a3b72007-02-12 00:53:46 -0800457 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700458 return ecryptfs_write_inode_size_to_xattr(ecryptfs_inode);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -0800459 else
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700460 return ecryptfs_write_inode_size_to_header(ecryptfs_inode);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -0800461}
462
Michael Halcrow237fead2006-10-04 02:16:22 -0700463/**
Badari Pulavarty807b7eb2008-10-15 22:02:50 -0700464 * ecryptfs_write_end
Michael Halcrow237fead2006-10-04 02:16:22 -0700465 * @file: The eCryptfs file object
Badari Pulavarty807b7eb2008-10-15 22:02:50 -0700466 * @mapping: The eCryptfs object
467 * @pos: The file position
468 * @len: The length of the data (unused)
469 * @copied: The amount of data copied
Michael Halcrow237fead2006-10-04 02:16:22 -0700470 * @page: The eCryptfs page
Badari Pulavarty807b7eb2008-10-15 22:02:50 -0700471 * @fsdata: The fsdata (unused)
Michael Halcrow237fead2006-10-04 02:16:22 -0700472 *
473 * This is where we encrypt the data and pass the encrypted data to
474 * the lower filesystem. In OpenPGP-compatible mode, we operate on
475 * entire underlying packets.
476 */
Badari Pulavarty807b7eb2008-10-15 22:02:50 -0700477static int ecryptfs_write_end(struct file *file,
478 struct address_space *mapping,
479 loff_t pos, unsigned len, unsigned copied,
480 struct page *page, void *fsdata)
Michael Halcrow237fead2006-10-04 02:16:22 -0700481{
Badari Pulavarty807b7eb2008-10-15 22:02:50 -0700482 pgoff_t index = pos >> PAGE_CACHE_SHIFT;
483 unsigned from = pos & (PAGE_CACHE_SIZE - 1);
484 unsigned to = from + copied;
485 struct inode *ecryptfs_inode = mapping->host;
Michael Halcrowbf12be12007-10-16 01:28:11 -0700486 struct ecryptfs_crypt_stat *crypt_stat =
Al Virobef5bc22010-05-21 10:56:12 -0400487 &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
Michael Halcrow237fead2006-10-04 02:16:22 -0700488 int rc;
489
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800490 if (crypt_stat->flags & ECRYPTFS_NEW_FILE) {
Michael Halcrow237fead2006-10-04 02:16:22 -0700491 ecryptfs_printk(KERN_DEBUG, "ECRYPTFS_NEW_FILE flag set in "
492 "crypt_stat at memory location [%p]\n", crypt_stat);
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800493 crypt_stat->flags &= ~(ECRYPTFS_NEW_FILE);
Michael Halcrow237fead2006-10-04 02:16:22 -0700494 } else
495 ecryptfs_printk(KERN_DEBUG, "Not a new file\n");
496 ecryptfs_printk(KERN_DEBUG, "Calling fill_zeros_to_end_of_page"
Joe Perches888d57b2010-11-10 15:46:16 -0800497 "(page w/ index = [0x%.16lx], to = [%d])\n", index, to);
Tyler Hicks13a791b2009-04-13 15:29:27 -0500498 if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
499 rc = ecryptfs_write_lower_page_segment(ecryptfs_inode, page, 0,
500 to);
501 if (!rc) {
502 rc = copied;
503 fsstack_copy_inode_size(ecryptfs_inode,
504 ecryptfs_inode_to_lower(ecryptfs_inode));
505 }
506 goto out;
507 }
Michael Halcrowbf12be12007-10-16 01:28:11 -0700508 /* Fills in zeros if 'to' goes beyond inode size */
Michael Halcrow237fead2006-10-04 02:16:22 -0700509 rc = fill_zeros_to_end_of_page(page, to);
510 if (rc) {
511 ecryptfs_printk(KERN_WARNING, "Error attempting to fill "
Joe Perches888d57b2010-11-10 15:46:16 -0800512 "zeros in page with index = [0x%.16lx]\n", index);
Michael Halcrow237fead2006-10-04 02:16:22 -0700513 goto out;
514 }
Michael Halcrow0216f7f2007-10-16 01:28:08 -0700515 rc = ecryptfs_encrypt_page(page);
Michael Halcrow237fead2006-10-04 02:16:22 -0700516 if (rc) {
517 ecryptfs_printk(KERN_WARNING, "Error encrypting page (upper "
Joe Perches888d57b2010-11-10 15:46:16 -0800518 "index [0x%.16lx])\n", index);
Michael Halcrow237fead2006-10-04 02:16:22 -0700519 goto out;
520 }
Badari Pulavarty807b7eb2008-10-15 22:02:50 -0700521 if (pos + copied > i_size_read(ecryptfs_inode)) {
522 i_size_write(ecryptfs_inode, pos + copied);
Michael Halcrow237fead2006-10-04 02:16:22 -0700523 ecryptfs_printk(KERN_DEBUG, "Expanded file size to "
Joe Perches888d57b2010-11-10 15:46:16 -0800524 "[0x%.16llx]\n",
525 (unsigned long long)i_size_read(ecryptfs_inode));
Michael Halcrow237fead2006-10-04 02:16:22 -0700526 }
Michael Halcrowbf12be12007-10-16 01:28:11 -0700527 rc = ecryptfs_write_inode_size_to_metadata(ecryptfs_inode);
Michael Halcrowdd2a3b72007-02-12 00:53:46 -0800528 if (rc)
529 printk(KERN_ERR "Error writing inode size to metadata; "
530 "rc = [%d]\n", rc);
Badari Pulavarty807b7eb2008-10-15 22:02:50 -0700531 else
532 rc = copied;
Michael Halcrow237fead2006-10-04 02:16:22 -0700533out:
Badari Pulavarty807b7eb2008-10-15 22:02:50 -0700534 unlock_page(page);
535 page_cache_release(page);
Michael Halcrow237fead2006-10-04 02:16:22 -0700536 return rc;
537}
538
Michael Halcrow237fead2006-10-04 02:16:22 -0700539static sector_t ecryptfs_bmap(struct address_space *mapping, sector_t block)
540{
541 int rc = 0;
542 struct inode *inode;
543 struct inode *lower_inode;
544
545 inode = (struct inode *)mapping->host;
546 lower_inode = ecryptfs_inode_to_lower(inode);
547 if (lower_inode->i_mapping->a_ops->bmap)
548 rc = lower_inode->i_mapping->a_ops->bmap(lower_inode->i_mapping,
549 block);
550 return rc;
551}
552
Alexey Dobriyan7f094102009-09-21 17:01:10 -0700553const struct address_space_operations ecryptfs_aops = {
Michael Halcrow237fead2006-10-04 02:16:22 -0700554 .writepage = ecryptfs_writepage,
555 .readpage = ecryptfs_readpage,
Badari Pulavarty807b7eb2008-10-15 22:02:50 -0700556 .write_begin = ecryptfs_write_begin,
557 .write_end = ecryptfs_write_end,
Michael Halcrow237fead2006-10-04 02:16:22 -0700558 .bmap = ecryptfs_bmap,
Michael Halcrow237fead2006-10-04 02:16:22 -0700559};