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Commit | Line | Data |
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237fead6 MH |
1 | /** |
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 | |
dd2a3b7a | 9 | * Copyright (C) 2004-2007 International Business Machines Corp. |
237fead6 MH |
10 | * 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> | |
5a0e3ad6 | 35 | #include <linux/slab.h> |
0a688ad7 | 36 | #include <asm/unaligned.h> |
237fead6 MH |
37 | #include "ecryptfs_kernel.h" |
38 | ||
237fead6 | 39 | /** |
16a72c45 | 40 | * ecryptfs_get_locked_page |
237fead6 MH |
41 | * |
42 | * Get one page from cache or lower f/s, return error otherwise. | |
43 | * | |
16a72c45 | 44 | * Returns locked and up-to-date page (if ok), with increased |
237fead6 MH |
45 | * refcnt. |
46 | */ | |
02bd9799 | 47 | struct page *ecryptfs_get_locked_page(struct inode *inode, loff_t index) |
237fead6 | 48 | { |
02bd9799 | 49 | struct page *page = read_mapping_page(inode->i_mapping, index, NULL); |
16a72c45 MH |
50 | if (!IS_ERR(page)) |
51 | lock_page(page); | |
52 | return page; | |
237fead6 MH |
53 | } |
54 | ||
237fead6 MH |
55 | /** |
56 | * ecryptfs_writepage | |
57 | * @page: Page that is locked before this call is made | |
58 | * | |
59 | * Returns zero on success; non-zero otherwise | |
60 | */ | |
61 | static int ecryptfs_writepage(struct page *page, struct writeback_control *wbc) | |
62 | { | |
237fead6 MH |
63 | int rc; |
64 | ||
57db4e8d TL |
65 | /* |
66 | * Refuse to write the page out if we are called from reclaim context | |
67 | * since our writepage() path may potentially allocate memory when | |
68 | * calling into the lower fs vfs_write() which may in turn invoke | |
69 | * us again. | |
70 | */ | |
71 | if (current->flags & PF_MEMALLOC) { | |
72 | redirty_page_for_writepage(wbc, page); | |
73 | rc = 0; | |
74 | goto out; | |
75 | } | |
76 | ||
0216f7f7 | 77 | rc = ecryptfs_encrypt_page(page); |
237fead6 MH |
78 | if (rc) { |
79 | ecryptfs_printk(KERN_WARNING, "Error encrypting " | |
888d57bb | 80 | "page (upper index [0x%.16lx])\n", page->index); |
237fead6 MH |
81 | ClearPageUptodate(page); |
82 | goto out; | |
83 | } | |
84 | SetPageUptodate(page); | |
237fead6 | 85 | out: |
57db4e8d | 86 | unlock_page(page); |
237fead6 MH |
87 | return rc; |
88 | } | |
89 | ||
f4e60e6b TH |
90 | static void strip_xattr_flag(char *page_virt, |
91 | struct ecryptfs_crypt_stat *crypt_stat) | |
92 | { | |
93 | if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR) { | |
94 | size_t written; | |
95 | ||
96 | crypt_stat->flags &= ~ECRYPTFS_METADATA_IN_XATTR; | |
97 | ecryptfs_write_crypt_stat_flags(page_virt, crypt_stat, | |
98 | &written); | |
99 | crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR; | |
100 | } | |
101 | } | |
102 | ||
e77a56dd MH |
103 | /** |
104 | * Header Extent: | |
105 | * Octets 0-7: Unencrypted file size (big-endian) | |
106 | * Octets 8-15: eCryptfs special marker | |
107 | * Octets 16-19: Flags | |
108 | * Octet 16: File format version number (between 0 and 255) | |
109 | * Octets 17-18: Reserved | |
110 | * Octet 19: Bit 1 (lsb): Reserved | |
111 | * Bit 2: Encrypted? | |
112 | * Bits 3-8: Reserved | |
113 | * Octets 20-23: Header extent size (big-endian) | |
114 | * Octets 24-25: Number of header extents at front of file | |
115 | * (big-endian) | |
116 | * Octet 26: Begin RFC 2440 authentication token packet set | |
117 | */ | |
237fead6 | 118 | |
bf12be1c MH |
119 | /** |
120 | * ecryptfs_copy_up_encrypted_with_header | |
121 | * @page: Sort of a ``virtual'' representation of the encrypted lower | |
122 | * file. The actual lower file does not have the metadata in | |
123 | * the header. This is locked. | |
124 | * @crypt_stat: The eCryptfs inode's cryptographic context | |
125 | * | |
126 | * The ``view'' is the version of the file that userspace winds up | |
127 | * seeing, with the header information inserted. | |
128 | */ | |
129 | static int | |
130 | ecryptfs_copy_up_encrypted_with_header(struct page *page, | |
131 | struct ecryptfs_crypt_stat *crypt_stat) | |
132 | { | |
133 | loff_t extent_num_in_page = 0; | |
134 | loff_t num_extents_per_page = (PAGE_CACHE_SIZE | |
135 | / crypt_stat->extent_size); | |
136 | int rc = 0; | |
137 | ||
138 | while (extent_num_in_page < num_extents_per_page) { | |
d6a13c17 MH |
139 | loff_t view_extent_num = ((((loff_t)page->index) |
140 | * num_extents_per_page) | |
bf12be1c | 141 | + extent_num_in_page); |
cc11beff | 142 | size_t num_header_extents_at_front = |
fa3ef1cb | 143 | (crypt_stat->metadata_size / crypt_stat->extent_size); |
bf12be1c | 144 | |
cc11beff | 145 | if (view_extent_num < num_header_extents_at_front) { |
bf12be1c MH |
146 | /* This is a header extent */ |
147 | char *page_virt; | |
148 | ||
149 | page_virt = kmap_atomic(page, KM_USER0); | |
150 | memset(page_virt, 0, PAGE_CACHE_SIZE); | |
151 | /* TODO: Support more than one header extent */ | |
152 | if (view_extent_num == 0) { | |
157f1071 TH |
153 | size_t written; |
154 | ||
bf12be1c MH |
155 | rc = ecryptfs_read_xattr_region( |
156 | page_virt, page->mapping->host); | |
f4e60e6b | 157 | strip_xattr_flag(page_virt + 16, crypt_stat); |
157f1071 TH |
158 | ecryptfs_write_header_metadata(page_virt + 20, |
159 | crypt_stat, | |
160 | &written); | |
bf12be1c MH |
161 | } |
162 | kunmap_atomic(page_virt, KM_USER0); | |
163 | flush_dcache_page(page); | |
164 | if (rc) { | |
bf12be1c | 165 | printk(KERN_ERR "%s: Error reading xattr " |
18d1dbf1 | 166 | "region; rc = [%d]\n", __func__, rc); |
bf12be1c MH |
167 | goto out; |
168 | } | |
bf12be1c MH |
169 | } else { |
170 | /* This is an encrypted data extent */ | |
171 | loff_t lower_offset = | |
cc11beff | 172 | ((view_extent_num * crypt_stat->extent_size) |
fa3ef1cb | 173 | - crypt_stat->metadata_size); |
bf12be1c MH |
174 | |
175 | rc = ecryptfs_read_lower_page_segment( | |
176 | page, (lower_offset >> PAGE_CACHE_SHIFT), | |
177 | (lower_offset & ~PAGE_CACHE_MASK), | |
178 | crypt_stat->extent_size, page->mapping->host); | |
179 | if (rc) { | |
180 | printk(KERN_ERR "%s: Error attempting to read " | |
181 | "extent at offset [%lld] in the lower " | |
18d1dbf1 | 182 | "file; rc = [%d]\n", __func__, |
bf12be1c MH |
183 | lower_offset, rc); |
184 | goto out; | |
185 | } | |
186 | } | |
187 | extent_num_in_page++; | |
188 | } | |
189 | out: | |
190 | return rc; | |
191 | } | |
192 | ||
237fead6 MH |
193 | /** |
194 | * ecryptfs_readpage | |
bf12be1c MH |
195 | * @file: An eCryptfs file |
196 | * @page: Page from eCryptfs inode mapping into which to stick the read data | |
237fead6 MH |
197 | * |
198 | * Read in a page, decrypting if necessary. | |
199 | * | |
200 | * Returns zero on success; non-zero on error. | |
201 | */ | |
202 | static int ecryptfs_readpage(struct file *file, struct page *page) | |
203 | { | |
bf12be1c | 204 | struct ecryptfs_crypt_stat *crypt_stat = |
bef5bc24 | 205 | &ecryptfs_inode_to_private(page->mapping->host)->crypt_stat; |
237fead6 | 206 | int rc = 0; |
237fead6 | 207 | |
fed8859b | 208 | if (!crypt_stat || !(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) { |
bf12be1c MH |
209 | rc = ecryptfs_read_lower_page_segment(page, page->index, 0, |
210 | PAGE_CACHE_SIZE, | |
211 | page->mapping->host); | |
e77a56dd MH |
212 | } else if (crypt_stat->flags & ECRYPTFS_VIEW_AS_ENCRYPTED) { |
213 | if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR) { | |
bf12be1c MH |
214 | rc = ecryptfs_copy_up_encrypted_with_header(page, |
215 | crypt_stat); | |
216 | if (rc) { | |
217 | printk(KERN_ERR "%s: Error attempting to copy " | |
218 | "the encrypted content from the lower " | |
219 | "file whilst inserting the metadata " | |
220 | "from the xattr into the header; rc = " | |
18d1dbf1 | 221 | "[%d]\n", __func__, rc); |
bf12be1c | 222 | goto out; |
e77a56dd | 223 | } |
bf12be1c | 224 | |
e77a56dd | 225 | } else { |
bf12be1c MH |
226 | rc = ecryptfs_read_lower_page_segment( |
227 | page, page->index, 0, PAGE_CACHE_SIZE, | |
228 | page->mapping->host); | |
e77a56dd MH |
229 | if (rc) { |
230 | printk(KERN_ERR "Error reading page; rc = " | |
231 | "[%d]\n", rc); | |
232 | goto out; | |
233 | } | |
234 | } | |
237fead6 | 235 | } else { |
0216f7f7 | 236 | rc = ecryptfs_decrypt_page(page); |
237fead6 | 237 | if (rc) { |
237fead6 MH |
238 | ecryptfs_printk(KERN_ERR, "Error decrypting page; " |
239 | "rc = [%d]\n", rc); | |
240 | goto out; | |
241 | } | |
242 | } | |
237fead6 | 243 | out: |
16a72c45 MH |
244 | if (rc) |
245 | ClearPageUptodate(page); | |
246 | else | |
247 | SetPageUptodate(page); | |
888d57bb | 248 | ecryptfs_printk(KERN_DEBUG, "Unlocking page with index = [0x%.16lx]\n", |
237fead6 MH |
249 | page->index); |
250 | unlock_page(page); | |
251 | return rc; | |
252 | } | |
253 | ||
dd2a3b7a MH |
254 | /** |
255 | * Called with lower inode mutex held. | |
256 | */ | |
237fead6 MH |
257 | static int fill_zeros_to_end_of_page(struct page *page, unsigned int to) |
258 | { | |
259 | struct inode *inode = page->mapping->host; | |
260 | int end_byte_in_page; | |
237fead6 | 261 | |
9d8b8ce5 MH |
262 | if ((i_size_read(inode) / PAGE_CACHE_SIZE) != page->index) |
263 | goto out; | |
264 | end_byte_in_page = i_size_read(inode) % PAGE_CACHE_SIZE; | |
265 | if (to > end_byte_in_page) | |
266 | end_byte_in_page = to; | |
eebd2aa3 | 267 | zero_user_segment(page, end_byte_in_page, PAGE_CACHE_SIZE); |
237fead6 | 268 | out: |
9d8b8ce5 | 269 | return 0; |
237fead6 MH |
270 | } |
271 | ||
e4465fda | 272 | /** |
807b7ebe | 273 | * ecryptfs_write_begin |
e4465fda | 274 | * @file: The eCryptfs file |
807b7ebe BP |
275 | * @mapping: The eCryptfs object |
276 | * @pos: The file offset at which to start writing | |
277 | * @len: Length of the write | |
278 | * @flags: Various flags | |
279 | * @pagep: Pointer to return the page | |
280 | * @fsdata: Pointer to return fs data (unused) | |
e4465fda MH |
281 | * |
282 | * This function must zero any hole we create | |
283 | * | |
284 | * Returns zero on success; non-zero otherwise | |
285 | */ | |
807b7ebe BP |
286 | static int ecryptfs_write_begin(struct file *file, |
287 | struct address_space *mapping, | |
288 | loff_t pos, unsigned len, unsigned flags, | |
289 | struct page **pagep, void **fsdata) | |
237fead6 | 290 | { |
807b7ebe BP |
291 | pgoff_t index = pos >> PAGE_CACHE_SHIFT; |
292 | struct page *page; | |
7a3f595c | 293 | loff_t prev_page_end_size; |
e4465fda | 294 | int rc = 0; |
237fead6 | 295 | |
54566b2c | 296 | page = grab_cache_page_write_begin(mapping, index, flags); |
807b7ebe BP |
297 | if (!page) |
298 | return -ENOMEM; | |
299 | *pagep = page; | |
300 | ||
24562486 | 301 | prev_page_end_size = ((loff_t)index << PAGE_CACHE_SHIFT); |
16a72c45 | 302 | if (!PageUptodate(page)) { |
e4465fda | 303 | struct ecryptfs_crypt_stat *crypt_stat = |
bef5bc24 | 304 | &ecryptfs_inode_to_private(mapping->host)->crypt_stat; |
e4465fda | 305 | |
fed8859b | 306 | if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) { |
e4465fda | 307 | rc = ecryptfs_read_lower_page_segment( |
807b7ebe | 308 | page, index, 0, PAGE_CACHE_SIZE, mapping->host); |
e4465fda MH |
309 | if (rc) { |
310 | printk(KERN_ERR "%s: Error attemping to read " | |
311 | "lower page segment; rc = [%d]\n", | |
18d1dbf1 | 312 | __func__, rc); |
e4465fda MH |
313 | ClearPageUptodate(page); |
314 | goto out; | |
315 | } else | |
316 | SetPageUptodate(page); | |
317 | } else if (crypt_stat->flags & ECRYPTFS_VIEW_AS_ENCRYPTED) { | |
318 | if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR) { | |
319 | rc = ecryptfs_copy_up_encrypted_with_header( | |
320 | page, crypt_stat); | |
321 | if (rc) { | |
322 | printk(KERN_ERR "%s: Error attempting " | |
323 | "to copy the encrypted content " | |
324 | "from the lower file whilst " | |
325 | "inserting the metadata from " | |
326 | "the xattr into the header; rc " | |
18d1dbf1 | 327 | "= [%d]\n", __func__, rc); |
e4465fda MH |
328 | ClearPageUptodate(page); |
329 | goto out; | |
330 | } | |
331 | SetPageUptodate(page); | |
332 | } else { | |
333 | rc = ecryptfs_read_lower_page_segment( | |
807b7ebe BP |
334 | page, index, 0, PAGE_CACHE_SIZE, |
335 | mapping->host); | |
e4465fda MH |
336 | if (rc) { |
337 | printk(KERN_ERR "%s: Error reading " | |
338 | "page; rc = [%d]\n", | |
18d1dbf1 | 339 | __func__, rc); |
e4465fda MH |
340 | ClearPageUptodate(page); |
341 | goto out; | |
342 | } | |
343 | SetPageUptodate(page); | |
344 | } | |
345 | } else { | |
24562486 FS |
346 | if (prev_page_end_size |
347 | >= i_size_read(page->mapping->host)) { | |
348 | zero_user(page, 0, PAGE_CACHE_SIZE); | |
349 | } else { | |
350 | rc = ecryptfs_decrypt_page(page); | |
351 | if (rc) { | |
352 | printk(KERN_ERR "%s: Error decrypting " | |
353 | "page at index [%ld]; " | |
354 | "rc = [%d]\n", | |
355 | __func__, page->index, rc); | |
356 | ClearPageUptodate(page); | |
357 | goto out; | |
358 | } | |
e4465fda | 359 | } |
16a72c45 | 360 | SetPageUptodate(page); |
e4465fda | 361 | } |
16a72c45 | 362 | } |
e4465fda MH |
363 | /* If creating a page or more of holes, zero them out via truncate. |
364 | * Note, this will increase i_size. */ | |
807b7ebe | 365 | if (index != 0) { |
7a3f595c | 366 | if (prev_page_end_size > i_size_read(page->mapping->host)) { |
240e2df5 | 367 | rc = ecryptfs_truncate(file->f_path.dentry, |
7a3f595c | 368 | prev_page_end_size); |
240e2df5 | 369 | if (rc) { |
e4465fda | 370 | printk(KERN_ERR "%s: Error on attempt to " |
240e2df5 | 371 | "truncate to (higher) offset [%lld];" |
18d1dbf1 | 372 | " rc = [%d]\n", __func__, |
e4465fda | 373 | prev_page_end_size, rc); |
240e2df5 MH |
374 | goto out; |
375 | } | |
53a2731f | 376 | } |
7a3f595c | 377 | } |
e4465fda MH |
378 | /* Writing to a new page, and creating a small hole from start |
379 | * of page? Zero it out. */ | |
807b7ebe BP |
380 | if ((i_size_read(mapping->host) == prev_page_end_size) |
381 | && (pos != 0)) | |
eebd2aa3 | 382 | zero_user(page, 0, PAGE_CACHE_SIZE); |
237fead6 | 383 | out: |
50f198ae TH |
384 | if (unlikely(rc)) { |
385 | unlock_page(page); | |
386 | page_cache_release(page); | |
387 | *pagep = NULL; | |
388 | } | |
237fead6 MH |
389 | return rc; |
390 | } | |
391 | ||
237fead6 MH |
392 | /** |
393 | * ecryptfs_write_inode_size_to_header | |
394 | * | |
395 | * Writes the lower file size to the first 8 bytes of the header. | |
396 | * | |
397 | * Returns zero on success; non-zero on error. | |
398 | */ | |
0216f7f7 | 399 | static int ecryptfs_write_inode_size_to_header(struct inode *ecryptfs_inode) |
237fead6 | 400 | { |
0216f7f7 MH |
401 | char *file_size_virt; |
402 | int rc; | |
237fead6 | 403 | |
0216f7f7 MH |
404 | file_size_virt = kmalloc(sizeof(u64), GFP_KERNEL); |
405 | if (!file_size_virt) { | |
406 | rc = -ENOMEM; | |
ae73fc09 MH |
407 | goto out; |
408 | } | |
0a688ad7 | 409 | put_unaligned_be64(i_size_read(ecryptfs_inode), file_size_virt); |
0216f7f7 MH |
410 | rc = ecryptfs_write_lower(ecryptfs_inode, file_size_virt, 0, |
411 | sizeof(u64)); | |
412 | kfree(file_size_virt); | |
96a7b9c2 | 413 | if (rc < 0) |
0216f7f7 | 414 | printk(KERN_ERR "%s: Error writing file size to header; " |
18d1dbf1 | 415 | "rc = [%d]\n", __func__, rc); |
96a7b9c2 TH |
416 | else |
417 | rc = 0; | |
237fead6 MH |
418 | out: |
419 | return rc; | |
420 | } | |
421 | ||
0216f7f7 MH |
422 | struct kmem_cache *ecryptfs_xattr_cache; |
423 | ||
424 | static int ecryptfs_write_inode_size_to_xattr(struct inode *ecryptfs_inode) | |
dd2a3b7a MH |
425 | { |
426 | ssize_t size; | |
427 | void *xattr_virt; | |
0216f7f7 MH |
428 | struct dentry *lower_dentry = |
429 | ecryptfs_inode_to_private(ecryptfs_inode)->lower_file->f_dentry; | |
430 | struct inode *lower_inode = lower_dentry->d_inode; | |
dd2a3b7a MH |
431 | int rc; |
432 | ||
0216f7f7 MH |
433 | if (!lower_inode->i_op->getxattr || !lower_inode->i_op->setxattr) { |
434 | printk(KERN_WARNING | |
435 | "No support for setting xattr in lower filesystem\n"); | |
436 | rc = -ENOSYS; | |
437 | goto out; | |
438 | } | |
dd2a3b7a MH |
439 | xattr_virt = kmem_cache_alloc(ecryptfs_xattr_cache, GFP_KERNEL); |
440 | if (!xattr_virt) { | |
441 | printk(KERN_ERR "Out of memory whilst attempting to write " | |
442 | "inode size to xattr\n"); | |
443 | rc = -ENOMEM; | |
444 | goto out; | |
445 | } | |
0216f7f7 MH |
446 | mutex_lock(&lower_inode->i_mutex); |
447 | size = lower_inode->i_op->getxattr(lower_dentry, ECRYPTFS_XATTR_NAME, | |
448 | xattr_virt, PAGE_CACHE_SIZE); | |
dd2a3b7a MH |
449 | if (size < 0) |
450 | size = 8; | |
0a688ad7 | 451 | put_unaligned_be64(i_size_read(ecryptfs_inode), xattr_virt); |
0216f7f7 MH |
452 | rc = lower_inode->i_op->setxattr(lower_dentry, ECRYPTFS_XATTR_NAME, |
453 | xattr_virt, size, 0); | |
454 | mutex_unlock(&lower_inode->i_mutex); | |
dd2a3b7a MH |
455 | if (rc) |
456 | printk(KERN_ERR "Error whilst attempting to write inode size " | |
457 | "to lower file xattr; rc = [%d]\n", rc); | |
458 | kmem_cache_free(ecryptfs_xattr_cache, xattr_virt); | |
459 | out: | |
460 | return rc; | |
461 | } | |
462 | ||
0216f7f7 | 463 | int ecryptfs_write_inode_size_to_metadata(struct inode *ecryptfs_inode) |
dd2a3b7a MH |
464 | { |
465 | struct ecryptfs_crypt_stat *crypt_stat; | |
466 | ||
0216f7f7 | 467 | crypt_stat = &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat; |
13a791b4 | 468 | BUG_ON(!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)); |
dd2a3b7a | 469 | if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR) |
0216f7f7 | 470 | return ecryptfs_write_inode_size_to_xattr(ecryptfs_inode); |
dd2a3b7a | 471 | else |
0216f7f7 | 472 | return ecryptfs_write_inode_size_to_header(ecryptfs_inode); |
dd2a3b7a MH |
473 | } |
474 | ||
237fead6 | 475 | /** |
807b7ebe | 476 | * ecryptfs_write_end |
237fead6 | 477 | * @file: The eCryptfs file object |
807b7ebe BP |
478 | * @mapping: The eCryptfs object |
479 | * @pos: The file position | |
480 | * @len: The length of the data (unused) | |
481 | * @copied: The amount of data copied | |
237fead6 | 482 | * @page: The eCryptfs page |
807b7ebe | 483 | * @fsdata: The fsdata (unused) |
237fead6 MH |
484 | * |
485 | * This is where we encrypt the data and pass the encrypted data to | |
486 | * the lower filesystem. In OpenPGP-compatible mode, we operate on | |
487 | * entire underlying packets. | |
488 | */ | |
807b7ebe BP |
489 | static int ecryptfs_write_end(struct file *file, |
490 | struct address_space *mapping, | |
491 | loff_t pos, unsigned len, unsigned copied, | |
492 | struct page *page, void *fsdata) | |
237fead6 | 493 | { |
807b7ebe BP |
494 | pgoff_t index = pos >> PAGE_CACHE_SHIFT; |
495 | unsigned from = pos & (PAGE_CACHE_SIZE - 1); | |
496 | unsigned to = from + copied; | |
497 | struct inode *ecryptfs_inode = mapping->host; | |
bf12be1c | 498 | struct ecryptfs_crypt_stat *crypt_stat = |
bef5bc24 | 499 | &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat; |
237fead6 | 500 | int rc; |
57db4e8d | 501 | int need_unlock_page = 1; |
237fead6 | 502 | |
237fead6 | 503 | ecryptfs_printk(KERN_DEBUG, "Calling fill_zeros_to_end_of_page" |
888d57bb | 504 | "(page w/ index = [0x%.16lx], to = [%d])\n", index, to); |
13a791b4 TH |
505 | if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) { |
506 | rc = ecryptfs_write_lower_page_segment(ecryptfs_inode, page, 0, | |
507 | to); | |
508 | if (!rc) { | |
509 | rc = copied; | |
510 | fsstack_copy_inode_size(ecryptfs_inode, | |
511 | ecryptfs_inode_to_lower(ecryptfs_inode)); | |
512 | } | |
513 | goto out; | |
514 | } | |
bf12be1c | 515 | /* Fills in zeros if 'to' goes beyond inode size */ |
237fead6 MH |
516 | rc = fill_zeros_to_end_of_page(page, to); |
517 | if (rc) { | |
518 | ecryptfs_printk(KERN_WARNING, "Error attempting to fill " | |
888d57bb | 519 | "zeros in page with index = [0x%.16lx]\n", index); |
237fead6 MH |
520 | goto out; |
521 | } | |
57db4e8d TL |
522 | set_page_dirty(page); |
523 | unlock_page(page); | |
524 | need_unlock_page = 0; | |
807b7ebe BP |
525 | if (pos + copied > i_size_read(ecryptfs_inode)) { |
526 | i_size_write(ecryptfs_inode, pos + copied); | |
237fead6 | 527 | ecryptfs_printk(KERN_DEBUG, "Expanded file size to " |
888d57bb JP |
528 | "[0x%.16llx]\n", |
529 | (unsigned long long)i_size_read(ecryptfs_inode)); | |
57db4e8d TL |
530 | balance_dirty_pages_ratelimited(mapping); |
531 | rc = ecryptfs_write_inode_size_to_metadata(ecryptfs_inode); | |
532 | if (rc) { | |
533 | printk(KERN_ERR "Error writing inode size to metadata; " | |
534 | "rc = [%d]\n", rc); | |
535 | goto out; | |
536 | } | |
237fead6 | 537 | } |
57db4e8d | 538 | rc = copied; |
237fead6 | 539 | out: |
57db4e8d TL |
540 | if (need_unlock_page) |
541 | unlock_page(page); | |
807b7ebe | 542 | page_cache_release(page); |
237fead6 MH |
543 | return rc; |
544 | } | |
545 | ||
237fead6 MH |
546 | static sector_t ecryptfs_bmap(struct address_space *mapping, sector_t block) |
547 | { | |
548 | int rc = 0; | |
549 | struct inode *inode; | |
550 | struct inode *lower_inode; | |
551 | ||
552 | inode = (struct inode *)mapping->host; | |
553 | lower_inode = ecryptfs_inode_to_lower(inode); | |
554 | if (lower_inode->i_mapping->a_ops->bmap) | |
555 | rc = lower_inode->i_mapping->a_ops->bmap(lower_inode->i_mapping, | |
556 | block); | |
557 | return rc; | |
558 | } | |
559 | ||
7f09410b | 560 | const struct address_space_operations ecryptfs_aops = { |
237fead6 MH |
561 | .writepage = ecryptfs_writepage, |
562 | .readpage = ecryptfs_readpage, | |
807b7ebe BP |
563 | .write_begin = ecryptfs_write_begin, |
564 | .write_end = ecryptfs_write_end, | |
237fead6 | 565 | .bmap = ecryptfs_bmap, |
237fead6 | 566 | }; |