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> | |
35 | #include "ecryptfs_kernel.h" | |
36 | ||
37 | struct kmem_cache *ecryptfs_lower_page_cache; | |
38 | ||
39 | /** | |
40 | * ecryptfs_get1page | |
41 | * | |
42 | * Get one page from cache or lower f/s, return error otherwise. | |
43 | * | |
44 | * Returns unlocked and up-to-date page (if ok), with increased | |
45 | * refcnt. | |
46 | */ | |
47 | static struct page *ecryptfs_get1page(struct file *file, int index) | |
48 | { | |
49 | struct page *page; | |
50 | struct dentry *dentry; | |
51 | struct inode *inode; | |
52 | struct address_space *mapping; | |
53 | ||
bd243a4b | 54 | dentry = file->f_path.dentry; |
237fead6 MH |
55 | inode = dentry->d_inode; |
56 | mapping = inode->i_mapping; | |
57 | page = read_cache_page(mapping, index, | |
58 | (filler_t *)mapping->a_ops->readpage, | |
59 | (void *)file); | |
60 | if (IS_ERR(page)) | |
61 | goto out; | |
62 | wait_on_page_locked(page); | |
63 | out: | |
64 | return page; | |
65 | } | |
66 | ||
67 | static | |
68 | int write_zeros(struct file *file, pgoff_t index, int start, int num_zeros); | |
69 | ||
70 | /** | |
71 | * ecryptfs_fill_zeros | |
72 | * @file: The ecryptfs file | |
73 | * @new_length: The new length of the data in the underlying file; | |
74 | * everything between the prior end of the file and the | |
75 | * new end of the file will be filled with zero's. | |
76 | * new_length must be greater than current length | |
77 | * | |
78 | * Function for handling lseek-ing past the end of the file. | |
79 | * | |
80 | * This function does not support shrinking, only growing a file. | |
81 | * | |
82 | * Returns zero on success; non-zero otherwise. | |
83 | */ | |
84 | int ecryptfs_fill_zeros(struct file *file, loff_t new_length) | |
85 | { | |
86 | int rc = 0; | |
bd243a4b | 87 | struct dentry *dentry = file->f_path.dentry; |
237fead6 MH |
88 | struct inode *inode = dentry->d_inode; |
89 | pgoff_t old_end_page_index = 0; | |
90 | pgoff_t index = old_end_page_index; | |
91 | int old_end_pos_in_page = -1; | |
92 | pgoff_t new_end_page_index; | |
93 | int new_end_pos_in_page; | |
94 | loff_t cur_length = i_size_read(inode); | |
95 | ||
96 | if (cur_length != 0) { | |
97 | index = old_end_page_index = | |
98 | ((cur_length - 1) >> PAGE_CACHE_SHIFT); | |
99 | old_end_pos_in_page = ((cur_length - 1) & ~PAGE_CACHE_MASK); | |
100 | } | |
101 | new_end_page_index = ((new_length - 1) >> PAGE_CACHE_SHIFT); | |
102 | new_end_pos_in_page = ((new_length - 1) & ~PAGE_CACHE_MASK); | |
103 | ecryptfs_printk(KERN_DEBUG, "old_end_page_index = [0x%.16x]; " | |
104 | "old_end_pos_in_page = [%d]; " | |
105 | "new_end_page_index = [0x%.16x]; " | |
106 | "new_end_pos_in_page = [%d]\n", | |
107 | old_end_page_index, old_end_pos_in_page, | |
108 | new_end_page_index, new_end_pos_in_page); | |
109 | if (old_end_page_index == new_end_page_index) { | |
110 | /* Start and end are in the same page; we just need to | |
111 | * set a portion of the existing page to zero's */ | |
112 | rc = write_zeros(file, index, (old_end_pos_in_page + 1), | |
113 | (new_end_pos_in_page - old_end_pos_in_page)); | |
114 | if (rc) | |
115 | ecryptfs_printk(KERN_ERR, "write_zeros(file=[%p], " | |
116 | "index=[0x%.16x], " | |
117 | "old_end_pos_in_page=[d], " | |
118 | "(PAGE_CACHE_SIZE - new_end_pos_in_page" | |
119 | "=[%d]" | |
120 | ")=[d]) returned [%d]\n", file, index, | |
121 | old_end_pos_in_page, | |
122 | new_end_pos_in_page, | |
123 | (PAGE_CACHE_SIZE - new_end_pos_in_page), | |
124 | rc); | |
125 | goto out; | |
126 | } | |
127 | /* Fill the remainder of the previous last page with zeros */ | |
128 | rc = write_zeros(file, index, (old_end_pos_in_page + 1), | |
129 | ((PAGE_CACHE_SIZE - 1) - old_end_pos_in_page)); | |
130 | if (rc) { | |
131 | ecryptfs_printk(KERN_ERR, "write_zeros(file=[%p], " | |
132 | "index=[0x%.16x], old_end_pos_in_page=[d], " | |
133 | "(PAGE_CACHE_SIZE - old_end_pos_in_page)=[d]) " | |
134 | "returned [%d]\n", file, index, | |
135 | old_end_pos_in_page, | |
136 | (PAGE_CACHE_SIZE - old_end_pos_in_page), rc); | |
137 | goto out; | |
138 | } | |
139 | index++; | |
140 | while (index < new_end_page_index) { | |
141 | /* Fill all intermediate pages with zeros */ | |
142 | rc = write_zeros(file, index, 0, PAGE_CACHE_SIZE); | |
143 | if (rc) { | |
144 | ecryptfs_printk(KERN_ERR, "write_zeros(file=[%p], " | |
145 | "index=[0x%.16x], " | |
146 | "old_end_pos_in_page=[d], " | |
147 | "(PAGE_CACHE_SIZE - new_end_pos_in_page" | |
148 | "=[%d]" | |
149 | ")=[d]) returned [%d]\n", file, index, | |
150 | old_end_pos_in_page, | |
151 | new_end_pos_in_page, | |
152 | (PAGE_CACHE_SIZE - new_end_pos_in_page), | |
153 | rc); | |
154 | goto out; | |
155 | } | |
156 | index++; | |
157 | } | |
158 | /* Fill the portion at the beginning of the last new page with | |
159 | * zero's */ | |
160 | rc = write_zeros(file, index, 0, (new_end_pos_in_page + 1)); | |
161 | if (rc) { | |
162 | ecryptfs_printk(KERN_ERR, "write_zeros(file=" | |
163 | "[%p], index=[0x%.16x], 0, " | |
164 | "new_end_pos_in_page=[%d]" | |
165 | "returned [%d]\n", file, index, | |
166 | new_end_pos_in_page, rc); | |
167 | goto out; | |
168 | } | |
169 | out: | |
170 | return rc; | |
171 | } | |
172 | ||
173 | /** | |
174 | * ecryptfs_writepage | |
175 | * @page: Page that is locked before this call is made | |
176 | * | |
177 | * Returns zero on success; non-zero otherwise | |
178 | */ | |
179 | static int ecryptfs_writepage(struct page *page, struct writeback_control *wbc) | |
180 | { | |
181 | struct ecryptfs_page_crypt_context ctx; | |
182 | int rc; | |
183 | ||
184 | ctx.page = page; | |
185 | ctx.mode = ECRYPTFS_WRITEPAGE_MODE; | |
186 | ctx.param.wbc = wbc; | |
187 | rc = ecryptfs_encrypt_page(&ctx); | |
188 | if (rc) { | |
189 | ecryptfs_printk(KERN_WARNING, "Error encrypting " | |
190 | "page (upper index [0x%.16x])\n", page->index); | |
191 | ClearPageUptodate(page); | |
192 | goto out; | |
193 | } | |
194 | SetPageUptodate(page); | |
195 | unlock_page(page); | |
196 | out: | |
197 | return rc; | |
198 | } | |
199 | ||
200 | /** | |
201 | * Reads the data from the lower file file at index lower_page_index | |
202 | * and copies that data into page. | |
203 | * | |
204 | * @param page Page to fill | |
205 | * @param lower_page_index Index of the page in the lower file to get | |
206 | */ | |
207 | int ecryptfs_do_readpage(struct file *file, struct page *page, | |
208 | pgoff_t lower_page_index) | |
209 | { | |
210 | int rc; | |
211 | struct dentry *dentry; | |
212 | struct file *lower_file; | |
213 | struct dentry *lower_dentry; | |
214 | struct inode *inode; | |
215 | struct inode *lower_inode; | |
216 | char *page_data; | |
217 | struct page *lower_page = NULL; | |
218 | char *lower_page_data; | |
219 | const struct address_space_operations *lower_a_ops; | |
220 | ||
bd243a4b | 221 | dentry = file->f_path.dentry; |
237fead6 MH |
222 | lower_file = ecryptfs_file_to_lower(file); |
223 | lower_dentry = ecryptfs_dentry_to_lower(dentry); | |
224 | inode = dentry->d_inode; | |
225 | lower_inode = ecryptfs_inode_to_lower(inode); | |
226 | lower_a_ops = lower_inode->i_mapping->a_ops; | |
227 | lower_page = read_cache_page(lower_inode->i_mapping, lower_page_index, | |
228 | (filler_t *)lower_a_ops->readpage, | |
229 | (void *)lower_file); | |
230 | if (IS_ERR(lower_page)) { | |
231 | rc = PTR_ERR(lower_page); | |
232 | lower_page = NULL; | |
233 | ecryptfs_printk(KERN_ERR, "Error reading from page cache\n"); | |
234 | goto out; | |
235 | } | |
236 | wait_on_page_locked(lower_page); | |
237 | page_data = (char *)kmap(page); | |
238 | if (!page_data) { | |
239 | rc = -ENOMEM; | |
240 | ecryptfs_printk(KERN_ERR, "Error mapping page\n"); | |
241 | goto out; | |
242 | } | |
243 | lower_page_data = (char *)kmap(lower_page); | |
244 | if (!lower_page_data) { | |
245 | rc = -ENOMEM; | |
246 | ecryptfs_printk(KERN_ERR, "Error mapping page\n"); | |
247 | kunmap(page); | |
248 | goto out; | |
249 | } | |
250 | memcpy(page_data, lower_page_data, PAGE_CACHE_SIZE); | |
251 | kunmap(lower_page); | |
252 | kunmap(page); | |
253 | rc = 0; | |
254 | out: | |
255 | if (likely(lower_page)) | |
256 | page_cache_release(lower_page); | |
257 | if (rc == 0) | |
258 | SetPageUptodate(page); | |
259 | else | |
260 | ClearPageUptodate(page); | |
261 | return rc; | |
262 | } | |
e77a56dd MH |
263 | /** |
264 | * Header Extent: | |
265 | * Octets 0-7: Unencrypted file size (big-endian) | |
266 | * Octets 8-15: eCryptfs special marker | |
267 | * Octets 16-19: Flags | |
268 | * Octet 16: File format version number (between 0 and 255) | |
269 | * Octets 17-18: Reserved | |
270 | * Octet 19: Bit 1 (lsb): Reserved | |
271 | * Bit 2: Encrypted? | |
272 | * Bits 3-8: Reserved | |
273 | * Octets 20-23: Header extent size (big-endian) | |
274 | * Octets 24-25: Number of header extents at front of file | |
275 | * (big-endian) | |
276 | * Octet 26: Begin RFC 2440 authentication token packet set | |
277 | */ | |
278 | static void set_header_info(char *page_virt, | |
279 | struct ecryptfs_crypt_stat *crypt_stat) | |
280 | { | |
281 | size_t written; | |
282 | int save_num_header_extents_at_front = | |
283 | crypt_stat->num_header_extents_at_front; | |
284 | ||
285 | crypt_stat->num_header_extents_at_front = 1; | |
286 | ecryptfs_write_header_metadata(page_virt + 20, crypt_stat, &written); | |
287 | crypt_stat->num_header_extents_at_front = | |
288 | save_num_header_extents_at_front; | |
289 | } | |
237fead6 MH |
290 | |
291 | /** | |
292 | * ecryptfs_readpage | |
293 | * @file: This is an ecryptfs file | |
294 | * @page: ecryptfs associated page to stick the read data into | |
295 | * | |
296 | * Read in a page, decrypting if necessary. | |
297 | * | |
298 | * Returns zero on success; non-zero on error. | |
299 | */ | |
300 | static int ecryptfs_readpage(struct file *file, struct page *page) | |
301 | { | |
302 | int rc = 0; | |
303 | struct ecryptfs_crypt_stat *crypt_stat; | |
304 | ||
bd243a4b JJS |
305 | BUG_ON(!(file && file->f_path.dentry && file->f_path.dentry->d_inode)); |
306 | crypt_stat = &ecryptfs_inode_to_private(file->f_path.dentry->d_inode) | |
307 | ->crypt_stat; | |
237fead6 MH |
308 | if (!crypt_stat |
309 | || !ECRYPTFS_CHECK_FLAG(crypt_stat->flags, ECRYPTFS_ENCRYPTED) | |
310 | || ECRYPTFS_CHECK_FLAG(crypt_stat->flags, ECRYPTFS_NEW_FILE)) { | |
311 | ecryptfs_printk(KERN_DEBUG, | |
312 | "Passing through unencrypted page\n"); | |
313 | rc = ecryptfs_do_readpage(file, page, page->index); | |
314 | if (rc) { | |
315 | ecryptfs_printk(KERN_ERR, "Error reading page; rc = " | |
316 | "[%d]\n", rc); | |
317 | goto out; | |
318 | } | |
e77a56dd MH |
319 | } else if (crypt_stat->flags & ECRYPTFS_VIEW_AS_ENCRYPTED) { |
320 | if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR) { | |
321 | int num_pages_in_header_region = | |
322 | (crypt_stat->header_extent_size | |
323 | / PAGE_CACHE_SIZE); | |
324 | ||
325 | if (page->index < num_pages_in_header_region) { | |
326 | char *page_virt; | |
327 | ||
328 | page_virt = (char *)kmap(page); | |
329 | if (!page_virt) { | |
330 | rc = -ENOMEM; | |
331 | printk(KERN_ERR "Error mapping page\n"); | |
332 | goto out; | |
333 | } | |
334 | memset(page_virt, 0, PAGE_CACHE_SIZE); | |
335 | if (page->index == 0) { | |
336 | rc = ecryptfs_read_xattr_region( | |
337 | page_virt, file->f_path.dentry); | |
338 | set_header_info(page_virt, crypt_stat); | |
339 | } | |
340 | kunmap(page); | |
341 | if (rc) { | |
342 | printk(KERN_ERR "Error reading xattr " | |
343 | "region\n"); | |
344 | goto out; | |
345 | } | |
346 | } else { | |
347 | rc = ecryptfs_do_readpage( | |
348 | file, page, | |
349 | (page->index | |
350 | - num_pages_in_header_region)); | |
351 | if (rc) { | |
352 | printk(KERN_ERR "Error reading page; " | |
353 | "rc = [%d]\n", rc); | |
354 | goto out; | |
355 | } | |
356 | } | |
357 | } else { | |
358 | rc = ecryptfs_do_readpage(file, page, page->index); | |
359 | if (rc) { | |
360 | printk(KERN_ERR "Error reading page; rc = " | |
361 | "[%d]\n", rc); | |
362 | goto out; | |
363 | } | |
364 | } | |
237fead6 MH |
365 | } else { |
366 | rc = ecryptfs_decrypt_page(file, page); | |
367 | if (rc) { | |
237fead6 MH |
368 | ecryptfs_printk(KERN_ERR, "Error decrypting page; " |
369 | "rc = [%d]\n", rc); | |
370 | goto out; | |
371 | } | |
372 | } | |
373 | SetPageUptodate(page); | |
374 | out: | |
375 | if (rc) | |
376 | ClearPageUptodate(page); | |
377 | ecryptfs_printk(KERN_DEBUG, "Unlocking page with index = [0x%.16x]\n", | |
378 | page->index); | |
379 | unlock_page(page); | |
380 | return rc; | |
381 | } | |
382 | ||
dd2a3b7a MH |
383 | /** |
384 | * Called with lower inode mutex held. | |
385 | */ | |
237fead6 MH |
386 | static int fill_zeros_to_end_of_page(struct page *page, unsigned int to) |
387 | { | |
388 | struct inode *inode = page->mapping->host; | |
389 | int end_byte_in_page; | |
390 | int rc = 0; | |
391 | char *page_virt; | |
392 | ||
393 | if ((i_size_read(inode) / PAGE_CACHE_SIZE) == page->index) { | |
394 | end_byte_in_page = i_size_read(inode) % PAGE_CACHE_SIZE; | |
395 | if (to > end_byte_in_page) | |
396 | end_byte_in_page = to; | |
397 | page_virt = kmap(page); | |
398 | if (!page_virt) { | |
399 | rc = -ENOMEM; | |
400 | ecryptfs_printk(KERN_WARNING, | |
401 | "Could not map page\n"); | |
402 | goto out; | |
403 | } | |
404 | memset((page_virt + end_byte_in_page), 0, | |
405 | (PAGE_CACHE_SIZE - end_byte_in_page)); | |
406 | kunmap(page); | |
407 | } | |
408 | out: | |
409 | return rc; | |
410 | } | |
411 | ||
412 | static int ecryptfs_prepare_write(struct file *file, struct page *page, | |
413 | unsigned from, unsigned to) | |
414 | { | |
415 | int rc = 0; | |
416 | ||
417 | kmap(page); | |
418 | if (from == 0 && to == PAGE_CACHE_SIZE) | |
419 | goto out; /* If we are writing a full page, it will be | |
420 | up to date. */ | |
421 | if (!PageUptodate(page)) | |
422 | rc = ecryptfs_do_readpage(file, page, page->index); | |
423 | out: | |
424 | return rc; | |
425 | } | |
426 | ||
427 | int ecryptfs_grab_and_map_lower_page(struct page **lower_page, | |
428 | char **lower_virt, | |
429 | struct inode *lower_inode, | |
430 | unsigned long lower_page_index) | |
431 | { | |
432 | int rc = 0; | |
433 | ||
434 | (*lower_page) = grab_cache_page(lower_inode->i_mapping, | |
435 | lower_page_index); | |
436 | if (!(*lower_page)) { | |
437 | ecryptfs_printk(KERN_ERR, "grab_cache_page for " | |
438 | "lower_page_index = [0x%.16x] failed\n", | |
439 | lower_page_index); | |
440 | rc = -EINVAL; | |
441 | goto out; | |
442 | } | |
443 | if (lower_virt) | |
444 | (*lower_virt) = kmap((*lower_page)); | |
445 | else | |
446 | kmap((*lower_page)); | |
447 | out: | |
448 | return rc; | |
449 | } | |
450 | ||
451 | int ecryptfs_writepage_and_release_lower_page(struct page *lower_page, | |
452 | struct inode *lower_inode, | |
453 | struct writeback_control *wbc) | |
454 | { | |
455 | int rc = 0; | |
456 | ||
457 | rc = lower_inode->i_mapping->a_ops->writepage(lower_page, wbc); | |
458 | if (rc) { | |
459 | ecryptfs_printk(KERN_ERR, "Error calling lower writepage(); " | |
460 | "rc = [%d]\n", rc); | |
461 | goto out; | |
462 | } | |
463 | lower_inode->i_mtime = lower_inode->i_ctime = CURRENT_TIME; | |
464 | page_cache_release(lower_page); | |
465 | out: | |
466 | return rc; | |
467 | } | |
468 | ||
469 | static void ecryptfs_unmap_and_release_lower_page(struct page *lower_page) | |
470 | { | |
471 | kunmap(lower_page); | |
472 | ecryptfs_printk(KERN_DEBUG, "Unlocking lower page with index = " | |
473 | "[0x%.16x]\n", lower_page->index); | |
474 | unlock_page(lower_page); | |
475 | page_cache_release(lower_page); | |
476 | } | |
477 | ||
478 | /** | |
479 | * ecryptfs_write_inode_size_to_header | |
480 | * | |
481 | * Writes the lower file size to the first 8 bytes of the header. | |
482 | * | |
483 | * Returns zero on success; non-zero on error. | |
484 | */ | |
dd2a3b7a MH |
485 | static int ecryptfs_write_inode_size_to_header(struct file *lower_file, |
486 | struct inode *lower_inode, | |
487 | struct inode *inode) | |
237fead6 MH |
488 | { |
489 | int rc = 0; | |
490 | struct page *header_page; | |
491 | char *header_virt; | |
492 | const struct address_space_operations *lower_a_ops; | |
493 | u64 file_size; | |
494 | ||
495 | rc = ecryptfs_grab_and_map_lower_page(&header_page, &header_virt, | |
496 | lower_inode, 0); | |
497 | if (rc) { | |
498 | ecryptfs_printk(KERN_ERR, "grab_cache_page for header page " | |
499 | "failed\n"); | |
500 | goto out; | |
501 | } | |
502 | lower_a_ops = lower_inode->i_mapping->a_ops; | |
503 | rc = lower_a_ops->prepare_write(lower_file, header_page, 0, 8); | |
504 | file_size = (u64)i_size_read(inode); | |
505 | ecryptfs_printk(KERN_DEBUG, "Writing size: [0x%.16x]\n", file_size); | |
506 | file_size = cpu_to_be64(file_size); | |
507 | memcpy(header_virt, &file_size, sizeof(u64)); | |
508 | rc = lower_a_ops->commit_write(lower_file, header_page, 0, 8); | |
509 | if (rc < 0) | |
510 | ecryptfs_printk(KERN_ERR, "Error commiting header page " | |
511 | "write\n"); | |
512 | ecryptfs_unmap_and_release_lower_page(header_page); | |
513 | lower_inode->i_mtime = lower_inode->i_ctime = CURRENT_TIME; | |
514 | mark_inode_dirty_sync(inode); | |
515 | out: | |
516 | return rc; | |
517 | } | |
518 | ||
dd2a3b7a MH |
519 | static int ecryptfs_write_inode_size_to_xattr(struct inode *lower_inode, |
520 | struct inode *inode, | |
521 | struct dentry *ecryptfs_dentry, | |
522 | int lower_i_mutex_held) | |
523 | { | |
524 | ssize_t size; | |
525 | void *xattr_virt; | |
526 | struct dentry *lower_dentry; | |
527 | u64 file_size; | |
528 | int rc; | |
529 | ||
530 | xattr_virt = kmem_cache_alloc(ecryptfs_xattr_cache, GFP_KERNEL); | |
531 | if (!xattr_virt) { | |
532 | printk(KERN_ERR "Out of memory whilst attempting to write " | |
533 | "inode size to xattr\n"); | |
534 | rc = -ENOMEM; | |
535 | goto out; | |
536 | } | |
537 | lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry); | |
538 | if (!lower_dentry->d_inode->i_op->getxattr) { | |
539 | printk(KERN_WARNING | |
540 | "No support for setting xattr in lower filesystem\n"); | |
541 | rc = -ENOSYS; | |
542 | kmem_cache_free(ecryptfs_xattr_cache, xattr_virt); | |
543 | goto out; | |
544 | } | |
545 | if (!lower_i_mutex_held) | |
546 | mutex_lock(&lower_dentry->d_inode->i_mutex); | |
547 | size = lower_dentry->d_inode->i_op->getxattr(lower_dentry, | |
548 | ECRYPTFS_XATTR_NAME, | |
549 | xattr_virt, | |
550 | PAGE_CACHE_SIZE); | |
551 | if (!lower_i_mutex_held) | |
552 | mutex_unlock(&lower_dentry->d_inode->i_mutex); | |
553 | if (size < 0) | |
554 | size = 8; | |
555 | file_size = (u64)i_size_read(inode); | |
556 | file_size = cpu_to_be64(file_size); | |
557 | memcpy(xattr_virt, &file_size, sizeof(u64)); | |
558 | if (!lower_i_mutex_held) | |
559 | mutex_lock(&lower_dentry->d_inode->i_mutex); | |
560 | rc = lower_dentry->d_inode->i_op->setxattr(lower_dentry, | |
561 | ECRYPTFS_XATTR_NAME, | |
562 | xattr_virt, size, 0); | |
563 | if (!lower_i_mutex_held) | |
564 | mutex_unlock(&lower_dentry->d_inode->i_mutex); | |
565 | if (rc) | |
566 | printk(KERN_ERR "Error whilst attempting to write inode size " | |
567 | "to lower file xattr; rc = [%d]\n", rc); | |
568 | kmem_cache_free(ecryptfs_xattr_cache, xattr_virt); | |
569 | out: | |
570 | return rc; | |
571 | } | |
572 | ||
573 | int | |
574 | ecryptfs_write_inode_size_to_metadata(struct file *lower_file, | |
575 | struct inode *lower_inode, | |
576 | struct inode *inode, | |
577 | struct dentry *ecryptfs_dentry, | |
578 | int lower_i_mutex_held) | |
579 | { | |
580 | struct ecryptfs_crypt_stat *crypt_stat; | |
581 | ||
582 | crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat; | |
583 | if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR) | |
584 | return ecryptfs_write_inode_size_to_xattr(lower_inode, inode, | |
585 | ecryptfs_dentry, | |
586 | lower_i_mutex_held); | |
587 | else | |
588 | return ecryptfs_write_inode_size_to_header(lower_file, | |
589 | lower_inode, | |
590 | inode); | |
591 | } | |
592 | ||
237fead6 MH |
593 | int ecryptfs_get_lower_page(struct page **lower_page, struct inode *lower_inode, |
594 | struct file *lower_file, | |
595 | unsigned long lower_page_index, int byte_offset, | |
596 | int region_bytes) | |
597 | { | |
598 | int rc = 0; | |
599 | ||
600 | rc = ecryptfs_grab_and_map_lower_page(lower_page, NULL, lower_inode, | |
601 | lower_page_index); | |
602 | if (rc) { | |
603 | ecryptfs_printk(KERN_ERR, "Error attempting to grab and map " | |
604 | "lower page with index [0x%.16x]\n", | |
605 | lower_page_index); | |
606 | goto out; | |
607 | } | |
608 | rc = lower_inode->i_mapping->a_ops->prepare_write(lower_file, | |
609 | (*lower_page), | |
610 | byte_offset, | |
611 | region_bytes); | |
612 | if (rc) { | |
613 | ecryptfs_printk(KERN_ERR, "prepare_write for " | |
614 | "lower_page_index = [0x%.16x] failed; rc = " | |
615 | "[%d]\n", lower_page_index, rc); | |
616 | } | |
617 | out: | |
618 | if (rc && (*lower_page)) { | |
619 | ecryptfs_unmap_and_release_lower_page(*lower_page); | |
620 | (*lower_page) = NULL; | |
621 | } | |
622 | return rc; | |
623 | } | |
624 | ||
625 | /** | |
626 | * ecryptfs_commit_lower_page | |
627 | * | |
628 | * Returns zero on success; non-zero on error | |
629 | */ | |
630 | int | |
631 | ecryptfs_commit_lower_page(struct page *lower_page, struct inode *lower_inode, | |
632 | struct file *lower_file, int byte_offset, | |
633 | int region_size) | |
634 | { | |
635 | int rc = 0; | |
636 | ||
637 | rc = lower_inode->i_mapping->a_ops->commit_write( | |
638 | lower_file, lower_page, byte_offset, region_size); | |
639 | if (rc < 0) { | |
640 | ecryptfs_printk(KERN_ERR, | |
641 | "Error committing write; rc = [%d]\n", rc); | |
642 | } else | |
643 | rc = 0; | |
644 | ecryptfs_unmap_and_release_lower_page(lower_page); | |
645 | return rc; | |
646 | } | |
647 | ||
648 | /** | |
649 | * ecryptfs_copy_page_to_lower | |
650 | * | |
651 | * Used for plaintext pass-through; no page index interpolation | |
652 | * required. | |
653 | */ | |
654 | int ecryptfs_copy_page_to_lower(struct page *page, struct inode *lower_inode, | |
655 | struct file *lower_file) | |
656 | { | |
657 | int rc = 0; | |
658 | struct page *lower_page; | |
659 | ||
660 | rc = ecryptfs_get_lower_page(&lower_page, lower_inode, lower_file, | |
661 | page->index, 0, PAGE_CACHE_SIZE); | |
662 | if (rc) { | |
663 | ecryptfs_printk(KERN_ERR, "Error attempting to get page " | |
664 | "at index [0x%.16x]\n", page->index); | |
665 | goto out; | |
666 | } | |
667 | /* TODO: aops */ | |
668 | memcpy((char *)page_address(lower_page), page_address(page), | |
669 | PAGE_CACHE_SIZE); | |
670 | rc = ecryptfs_commit_lower_page(lower_page, lower_inode, lower_file, | |
671 | 0, PAGE_CACHE_SIZE); | |
672 | if (rc) | |
673 | ecryptfs_printk(KERN_ERR, "Error attempting to commit page " | |
674 | "at index [0x%.16x]\n", page->index); | |
675 | out: | |
676 | return rc; | |
677 | } | |
678 | ||
dd2a3b7a MH |
679 | struct kmem_cache *ecryptfs_xattr_cache; |
680 | ||
237fead6 MH |
681 | /** |
682 | * ecryptfs_commit_write | |
683 | * @file: The eCryptfs file object | |
684 | * @page: The eCryptfs page | |
685 | * @from: Ignored (we rotate the page IV on each write) | |
686 | * @to: Ignored | |
687 | * | |
688 | * This is where we encrypt the data and pass the encrypted data to | |
689 | * the lower filesystem. In OpenPGP-compatible mode, we operate on | |
690 | * entire underlying packets. | |
691 | */ | |
692 | static int ecryptfs_commit_write(struct file *file, struct page *page, | |
693 | unsigned from, unsigned to) | |
694 | { | |
695 | struct ecryptfs_page_crypt_context ctx; | |
696 | loff_t pos; | |
697 | struct inode *inode; | |
698 | struct inode *lower_inode; | |
699 | struct file *lower_file; | |
700 | struct ecryptfs_crypt_stat *crypt_stat; | |
701 | int rc; | |
702 | ||
703 | inode = page->mapping->host; | |
704 | lower_inode = ecryptfs_inode_to_lower(inode); | |
705 | lower_file = ecryptfs_file_to_lower(file); | |
706 | mutex_lock(&lower_inode->i_mutex); | |
bd243a4b JJS |
707 | crypt_stat = &ecryptfs_inode_to_private(file->f_path.dentry->d_inode) |
708 | ->crypt_stat; | |
237fead6 MH |
709 | if (ECRYPTFS_CHECK_FLAG(crypt_stat->flags, ECRYPTFS_NEW_FILE)) { |
710 | ecryptfs_printk(KERN_DEBUG, "ECRYPTFS_NEW_FILE flag set in " | |
711 | "crypt_stat at memory location [%p]\n", crypt_stat); | |
dddfa461 | 712 | ECRYPTFS_CLEAR_FLAG(crypt_stat->flags, ECRYPTFS_NEW_FILE); |
237fead6 MH |
713 | } else |
714 | ecryptfs_printk(KERN_DEBUG, "Not a new file\n"); | |
715 | ecryptfs_printk(KERN_DEBUG, "Calling fill_zeros_to_end_of_page" | |
716 | "(page w/ index = [0x%.16x], to = [%d])\n", page->index, | |
717 | to); | |
718 | rc = fill_zeros_to_end_of_page(page, to); | |
719 | if (rc) { | |
720 | ecryptfs_printk(KERN_WARNING, "Error attempting to fill " | |
721 | "zeros in page with index = [0x%.16x]\n", | |
722 | page->index); | |
723 | goto out; | |
724 | } | |
725 | ctx.page = page; | |
726 | ctx.mode = ECRYPTFS_PREPARE_COMMIT_MODE; | |
727 | ctx.param.lower_file = lower_file; | |
728 | rc = ecryptfs_encrypt_page(&ctx); | |
729 | if (rc) { | |
730 | ecryptfs_printk(KERN_WARNING, "Error encrypting page (upper " | |
731 | "index [0x%.16x])\n", page->index); | |
732 | goto out; | |
733 | } | |
237fead6 MH |
734 | inode->i_blocks = lower_inode->i_blocks; |
735 | pos = (page->index << PAGE_CACHE_SHIFT) + to; | |
736 | if (pos > i_size_read(inode)) { | |
737 | i_size_write(inode, pos); | |
738 | ecryptfs_printk(KERN_DEBUG, "Expanded file size to " | |
739 | "[0x%.16x]\n", i_size_read(inode)); | |
740 | } | |
dd2a3b7a MH |
741 | rc = ecryptfs_write_inode_size_to_metadata(lower_file, lower_inode, |
742 | inode, file->f_dentry, | |
743 | ECRYPTFS_LOWER_I_MUTEX_HELD); | |
744 | if (rc) | |
745 | printk(KERN_ERR "Error writing inode size to metadata; " | |
746 | "rc = [%d]\n", rc); | |
237fead6 MH |
747 | lower_inode->i_mtime = lower_inode->i_ctime = CURRENT_TIME; |
748 | mark_inode_dirty_sync(inode); | |
749 | out: | |
750 | kunmap(page); /* mapped in prior call (prepare_write) */ | |
751 | if (rc < 0) | |
752 | ClearPageUptodate(page); | |
753 | else | |
754 | SetPageUptodate(page); | |
755 | mutex_unlock(&lower_inode->i_mutex); | |
756 | return rc; | |
757 | } | |
758 | ||
759 | /** | |
760 | * write_zeros | |
761 | * @file: The ecryptfs file | |
762 | * @index: The index in which we are writing | |
763 | * @start: The position after the last block of data | |
764 | * @num_zeros: The number of zeros to write | |
765 | * | |
766 | * Write a specified number of zero's to a page. | |
767 | * | |
768 | * (start + num_zeros) must be less than or equal to PAGE_CACHE_SIZE | |
769 | */ | |
770 | static | |
771 | int write_zeros(struct file *file, pgoff_t index, int start, int num_zeros) | |
772 | { | |
773 | int rc = 0; | |
774 | struct page *tmp_page; | |
775 | ||
776 | tmp_page = ecryptfs_get1page(file, index); | |
777 | if (IS_ERR(tmp_page)) { | |
778 | ecryptfs_printk(KERN_ERR, "Error getting page at index " | |
779 | "[0x%.16x]\n", index); | |
780 | rc = PTR_ERR(tmp_page); | |
781 | goto out; | |
782 | } | |
783 | kmap(tmp_page); | |
784 | rc = ecryptfs_prepare_write(file, tmp_page, start, start + num_zeros); | |
785 | if (rc) { | |
786 | ecryptfs_printk(KERN_ERR, "Error preparing to write zero's " | |
787 | "to remainder of page at index [0x%.16x]\n", | |
788 | index); | |
789 | kunmap(tmp_page); | |
790 | page_cache_release(tmp_page); | |
791 | goto out; | |
792 | } | |
793 | memset(((char *)page_address(tmp_page) + start), 0, num_zeros); | |
794 | rc = ecryptfs_commit_write(file, tmp_page, start, start + num_zeros); | |
795 | if (rc < 0) { | |
796 | ecryptfs_printk(KERN_ERR, "Error attempting to write zero's " | |
797 | "to remainder of page at index [0x%.16x]\n", | |
798 | index); | |
799 | kunmap(tmp_page); | |
800 | page_cache_release(tmp_page); | |
801 | goto out; | |
802 | } | |
803 | rc = 0; | |
804 | kunmap(tmp_page); | |
805 | page_cache_release(tmp_page); | |
806 | out: | |
807 | return rc; | |
808 | } | |
809 | ||
810 | static sector_t ecryptfs_bmap(struct address_space *mapping, sector_t block) | |
811 | { | |
812 | int rc = 0; | |
813 | struct inode *inode; | |
814 | struct inode *lower_inode; | |
815 | ||
816 | inode = (struct inode *)mapping->host; | |
817 | lower_inode = ecryptfs_inode_to_lower(inode); | |
818 | if (lower_inode->i_mapping->a_ops->bmap) | |
819 | rc = lower_inode->i_mapping->a_ops->bmap(lower_inode->i_mapping, | |
820 | block); | |
821 | return rc; | |
822 | } | |
823 | ||
824 | static void ecryptfs_sync_page(struct page *page) | |
825 | { | |
826 | struct inode *inode; | |
827 | struct inode *lower_inode; | |
828 | struct page *lower_page; | |
829 | ||
830 | inode = page->mapping->host; | |
831 | lower_inode = ecryptfs_inode_to_lower(inode); | |
832 | /* NOTE: Recently swapped with grab_cache_page(), since | |
833 | * sync_page() just makes sure that pending I/O gets done. */ | |
834 | lower_page = find_lock_page(lower_inode->i_mapping, page->index); | |
835 | if (!lower_page) { | |
836 | ecryptfs_printk(KERN_DEBUG, "find_lock_page failed\n"); | |
837 | return; | |
838 | } | |
839 | lower_page->mapping->a_ops->sync_page(lower_page); | |
840 | ecryptfs_printk(KERN_DEBUG, "Unlocking page with index = [0x%.16x]\n", | |
841 | lower_page->index); | |
842 | unlock_page(lower_page); | |
843 | page_cache_release(lower_page); | |
844 | } | |
845 | ||
846 | struct address_space_operations ecryptfs_aops = { | |
847 | .writepage = ecryptfs_writepage, | |
848 | .readpage = ecryptfs_readpage, | |
849 | .prepare_write = ecryptfs_prepare_write, | |
850 | .commit_write = ecryptfs_commit_write, | |
851 | .bmap = ecryptfs_bmap, | |
852 | .sync_page = ecryptfs_sync_page, | |
853 | }; |