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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> | |
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); | |
9d8b8ce5 MH |
237 | page_data = kmap_atomic(page, KM_USER0); |
238 | lower_page_data = kmap_atomic(lower_page, KM_USER1); | |
237fead6 | 239 | memcpy(page_data, lower_page_data, PAGE_CACHE_SIZE); |
9d8b8ce5 | 240 | kunmap_atomic(lower_page_data, KM_USER1); |
0a9ac382 | 241 | flush_dcache_page(lower_page); |
9d8b8ce5 | 242 | kunmap_atomic(page_data, KM_USER0); |
0a9ac382 | 243 | flush_dcache_page(page); |
237fead6 MH |
244 | rc = 0; |
245 | out: | |
246 | if (likely(lower_page)) | |
247 | page_cache_release(lower_page); | |
248 | if (rc == 0) | |
249 | SetPageUptodate(page); | |
250 | else | |
251 | ClearPageUptodate(page); | |
252 | return rc; | |
253 | } | |
e77a56dd MH |
254 | /** |
255 | * Header Extent: | |
256 | * Octets 0-7: Unencrypted file size (big-endian) | |
257 | * Octets 8-15: eCryptfs special marker | |
258 | * Octets 16-19: Flags | |
259 | * Octet 16: File format version number (between 0 and 255) | |
260 | * Octets 17-18: Reserved | |
261 | * Octet 19: Bit 1 (lsb): Reserved | |
262 | * Bit 2: Encrypted? | |
263 | * Bits 3-8: Reserved | |
264 | * Octets 20-23: Header extent size (big-endian) | |
265 | * Octets 24-25: Number of header extents at front of file | |
266 | * (big-endian) | |
267 | * Octet 26: Begin RFC 2440 authentication token packet set | |
268 | */ | |
269 | static void set_header_info(char *page_virt, | |
270 | struct ecryptfs_crypt_stat *crypt_stat) | |
271 | { | |
272 | size_t written; | |
273 | int save_num_header_extents_at_front = | |
274 | crypt_stat->num_header_extents_at_front; | |
275 | ||
276 | crypt_stat->num_header_extents_at_front = 1; | |
277 | ecryptfs_write_header_metadata(page_virt + 20, crypt_stat, &written); | |
278 | crypt_stat->num_header_extents_at_front = | |
279 | save_num_header_extents_at_front; | |
280 | } | |
237fead6 MH |
281 | |
282 | /** | |
283 | * ecryptfs_readpage | |
284 | * @file: This is an ecryptfs file | |
285 | * @page: ecryptfs associated page to stick the read data into | |
286 | * | |
287 | * Read in a page, decrypting if necessary. | |
288 | * | |
289 | * Returns zero on success; non-zero on error. | |
290 | */ | |
291 | static int ecryptfs_readpage(struct file *file, struct page *page) | |
292 | { | |
293 | int rc = 0; | |
294 | struct ecryptfs_crypt_stat *crypt_stat; | |
295 | ||
bd243a4b JJS |
296 | BUG_ON(!(file && file->f_path.dentry && file->f_path.dentry->d_inode)); |
297 | crypt_stat = &ecryptfs_inode_to_private(file->f_path.dentry->d_inode) | |
298 | ->crypt_stat; | |
237fead6 | 299 | if (!crypt_stat |
e2bd99ec MH |
300 | || !(crypt_stat->flags & ECRYPTFS_ENCRYPTED) |
301 | || (crypt_stat->flags & ECRYPTFS_NEW_FILE)) { | |
237fead6 MH |
302 | ecryptfs_printk(KERN_DEBUG, |
303 | "Passing through unencrypted page\n"); | |
304 | rc = ecryptfs_do_readpage(file, page, page->index); | |
305 | if (rc) { | |
306 | ecryptfs_printk(KERN_ERR, "Error reading page; rc = " | |
307 | "[%d]\n", rc); | |
308 | goto out; | |
309 | } | |
e77a56dd MH |
310 | } else if (crypt_stat->flags & ECRYPTFS_VIEW_AS_ENCRYPTED) { |
311 | if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR) { | |
312 | int num_pages_in_header_region = | |
313 | (crypt_stat->header_extent_size | |
314 | / PAGE_CACHE_SIZE); | |
315 | ||
316 | if (page->index < num_pages_in_header_region) { | |
317 | char *page_virt; | |
318 | ||
9d8b8ce5 | 319 | page_virt = kmap_atomic(page, KM_USER0); |
e77a56dd MH |
320 | memset(page_virt, 0, PAGE_CACHE_SIZE); |
321 | if (page->index == 0) { | |
322 | rc = ecryptfs_read_xattr_region( | |
323 | page_virt, file->f_path.dentry); | |
324 | set_header_info(page_virt, crypt_stat); | |
325 | } | |
9d8b8ce5 | 326 | kunmap_atomic(page_virt, KM_USER0); |
0a9ac382 | 327 | flush_dcache_page(page); |
e77a56dd MH |
328 | if (rc) { |
329 | printk(KERN_ERR "Error reading xattr " | |
330 | "region\n"); | |
331 | goto out; | |
332 | } | |
333 | } else { | |
334 | rc = ecryptfs_do_readpage( | |
335 | file, page, | |
336 | (page->index | |
337 | - num_pages_in_header_region)); | |
338 | if (rc) { | |
339 | printk(KERN_ERR "Error reading page; " | |
340 | "rc = [%d]\n", rc); | |
341 | goto out; | |
342 | } | |
343 | } | |
344 | } else { | |
345 | rc = ecryptfs_do_readpage(file, page, page->index); | |
346 | if (rc) { | |
347 | printk(KERN_ERR "Error reading page; rc = " | |
348 | "[%d]\n", rc); | |
349 | goto out; | |
350 | } | |
351 | } | |
237fead6 MH |
352 | } else { |
353 | rc = ecryptfs_decrypt_page(file, page); | |
354 | if (rc) { | |
237fead6 MH |
355 | ecryptfs_printk(KERN_ERR, "Error decrypting page; " |
356 | "rc = [%d]\n", rc); | |
357 | goto out; | |
358 | } | |
359 | } | |
360 | SetPageUptodate(page); | |
361 | out: | |
362 | if (rc) | |
363 | ClearPageUptodate(page); | |
364 | ecryptfs_printk(KERN_DEBUG, "Unlocking page with index = [0x%.16x]\n", | |
365 | page->index); | |
366 | unlock_page(page); | |
367 | return rc; | |
368 | } | |
369 | ||
dd2a3b7a MH |
370 | /** |
371 | * Called with lower inode mutex held. | |
372 | */ | |
237fead6 MH |
373 | static int fill_zeros_to_end_of_page(struct page *page, unsigned int to) |
374 | { | |
375 | struct inode *inode = page->mapping->host; | |
376 | int end_byte_in_page; | |
237fead6 MH |
377 | char *page_virt; |
378 | ||
9d8b8ce5 MH |
379 | if ((i_size_read(inode) / PAGE_CACHE_SIZE) != page->index) |
380 | goto out; | |
381 | end_byte_in_page = i_size_read(inode) % PAGE_CACHE_SIZE; | |
382 | if (to > end_byte_in_page) | |
383 | end_byte_in_page = to; | |
384 | page_virt = kmap_atomic(page, KM_USER0); | |
385 | memset((page_virt + end_byte_in_page), 0, | |
386 | (PAGE_CACHE_SIZE - end_byte_in_page)); | |
387 | kunmap_atomic(page_virt, KM_USER0); | |
0a9ac382 | 388 | flush_dcache_page(page); |
237fead6 | 389 | out: |
9d8b8ce5 | 390 | return 0; |
237fead6 MH |
391 | } |
392 | ||
393 | static int ecryptfs_prepare_write(struct file *file, struct page *page, | |
394 | unsigned from, unsigned to) | |
395 | { | |
396 | int rc = 0; | |
397 | ||
237fead6 MH |
398 | if (from == 0 && to == PAGE_CACHE_SIZE) |
399 | goto out; /* If we are writing a full page, it will be | |
400 | up to date. */ | |
401 | if (!PageUptodate(page)) | |
402 | rc = ecryptfs_do_readpage(file, page, page->index); | |
403 | out: | |
404 | return rc; | |
405 | } | |
406 | ||
237fead6 MH |
407 | int ecryptfs_writepage_and_release_lower_page(struct page *lower_page, |
408 | struct inode *lower_inode, | |
409 | struct writeback_control *wbc) | |
410 | { | |
411 | int rc = 0; | |
412 | ||
413 | rc = lower_inode->i_mapping->a_ops->writepage(lower_page, wbc); | |
414 | if (rc) { | |
415 | ecryptfs_printk(KERN_ERR, "Error calling lower writepage(); " | |
416 | "rc = [%d]\n", rc); | |
417 | goto out; | |
418 | } | |
419 | lower_inode->i_mtime = lower_inode->i_ctime = CURRENT_TIME; | |
420 | page_cache_release(lower_page); | |
421 | out: | |
422 | return rc; | |
423 | } | |
424 | ||
9d8b8ce5 | 425 | static void ecryptfs_release_lower_page(struct page *lower_page) |
237fead6 | 426 | { |
237fead6 MH |
427 | unlock_page(lower_page); |
428 | page_cache_release(lower_page); | |
429 | } | |
430 | ||
431 | /** | |
432 | * ecryptfs_write_inode_size_to_header | |
433 | * | |
434 | * Writes the lower file size to the first 8 bytes of the header. | |
435 | * | |
436 | * Returns zero on success; non-zero on error. | |
437 | */ | |
dd2a3b7a MH |
438 | static int ecryptfs_write_inode_size_to_header(struct file *lower_file, |
439 | struct inode *lower_inode, | |
440 | struct inode *inode) | |
237fead6 MH |
441 | { |
442 | int rc = 0; | |
443 | struct page *header_page; | |
444 | char *header_virt; | |
445 | const struct address_space_operations *lower_a_ops; | |
446 | u64 file_size; | |
447 | ||
9d8b8ce5 MH |
448 | header_page = grab_cache_page(lower_inode->i_mapping, 0); |
449 | if (!header_page) { | |
450 | ecryptfs_printk(KERN_ERR, "grab_cache_page for " | |
451 | "lower_page_index 0 failed\n"); | |
452 | rc = -EINVAL; | |
237fead6 MH |
453 | goto out; |
454 | } | |
455 | lower_a_ops = lower_inode->i_mapping->a_ops; | |
456 | rc = lower_a_ops->prepare_write(lower_file, header_page, 0, 8); | |
457 | file_size = (u64)i_size_read(inode); | |
458 | ecryptfs_printk(KERN_DEBUG, "Writing size: [0x%.16x]\n", file_size); | |
459 | file_size = cpu_to_be64(file_size); | |
9d8b8ce5 | 460 | header_virt = kmap_atomic(header_page, KM_USER0); |
237fead6 | 461 | memcpy(header_virt, &file_size, sizeof(u64)); |
9d8b8ce5 | 462 | kunmap_atomic(header_virt, KM_USER0); |
0a9ac382 | 463 | flush_dcache_page(header_page); |
237fead6 MH |
464 | rc = lower_a_ops->commit_write(lower_file, header_page, 0, 8); |
465 | if (rc < 0) | |
466 | ecryptfs_printk(KERN_ERR, "Error commiting header page " | |
467 | "write\n"); | |
9d8b8ce5 | 468 | ecryptfs_release_lower_page(header_page); |
237fead6 MH |
469 | lower_inode->i_mtime = lower_inode->i_ctime = CURRENT_TIME; |
470 | mark_inode_dirty_sync(inode); | |
471 | out: | |
472 | return rc; | |
473 | } | |
474 | ||
dd2a3b7a MH |
475 | static int ecryptfs_write_inode_size_to_xattr(struct inode *lower_inode, |
476 | struct inode *inode, | |
477 | struct dentry *ecryptfs_dentry, | |
478 | int lower_i_mutex_held) | |
479 | { | |
480 | ssize_t size; | |
481 | void *xattr_virt; | |
482 | struct dentry *lower_dentry; | |
483 | u64 file_size; | |
484 | int rc; | |
485 | ||
486 | xattr_virt = kmem_cache_alloc(ecryptfs_xattr_cache, GFP_KERNEL); | |
487 | if (!xattr_virt) { | |
488 | printk(KERN_ERR "Out of memory whilst attempting to write " | |
489 | "inode size to xattr\n"); | |
490 | rc = -ENOMEM; | |
491 | goto out; | |
492 | } | |
493 | lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry); | |
494 | if (!lower_dentry->d_inode->i_op->getxattr) { | |
495 | printk(KERN_WARNING | |
496 | "No support for setting xattr in lower filesystem\n"); | |
497 | rc = -ENOSYS; | |
498 | kmem_cache_free(ecryptfs_xattr_cache, xattr_virt); | |
499 | goto out; | |
500 | } | |
501 | if (!lower_i_mutex_held) | |
502 | mutex_lock(&lower_dentry->d_inode->i_mutex); | |
503 | size = lower_dentry->d_inode->i_op->getxattr(lower_dentry, | |
504 | ECRYPTFS_XATTR_NAME, | |
505 | xattr_virt, | |
506 | PAGE_CACHE_SIZE); | |
507 | if (!lower_i_mutex_held) | |
508 | mutex_unlock(&lower_dentry->d_inode->i_mutex); | |
509 | if (size < 0) | |
510 | size = 8; | |
511 | file_size = (u64)i_size_read(inode); | |
512 | file_size = cpu_to_be64(file_size); | |
513 | memcpy(xattr_virt, &file_size, sizeof(u64)); | |
514 | if (!lower_i_mutex_held) | |
515 | mutex_lock(&lower_dentry->d_inode->i_mutex); | |
516 | rc = lower_dentry->d_inode->i_op->setxattr(lower_dentry, | |
517 | ECRYPTFS_XATTR_NAME, | |
518 | xattr_virt, size, 0); | |
519 | if (!lower_i_mutex_held) | |
520 | mutex_unlock(&lower_dentry->d_inode->i_mutex); | |
521 | if (rc) | |
522 | printk(KERN_ERR "Error whilst attempting to write inode size " | |
523 | "to lower file xattr; rc = [%d]\n", rc); | |
524 | kmem_cache_free(ecryptfs_xattr_cache, xattr_virt); | |
525 | out: | |
526 | return rc; | |
527 | } | |
528 | ||
529 | int | |
530 | ecryptfs_write_inode_size_to_metadata(struct file *lower_file, | |
531 | struct inode *lower_inode, | |
532 | struct inode *inode, | |
533 | struct dentry *ecryptfs_dentry, | |
534 | int lower_i_mutex_held) | |
535 | { | |
536 | struct ecryptfs_crypt_stat *crypt_stat; | |
537 | ||
538 | crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat; | |
539 | if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR) | |
540 | return ecryptfs_write_inode_size_to_xattr(lower_inode, inode, | |
541 | ecryptfs_dentry, | |
542 | lower_i_mutex_held); | |
543 | else | |
544 | return ecryptfs_write_inode_size_to_header(lower_file, | |
545 | lower_inode, | |
546 | inode); | |
547 | } | |
548 | ||
237fead6 MH |
549 | int ecryptfs_get_lower_page(struct page **lower_page, struct inode *lower_inode, |
550 | struct file *lower_file, | |
551 | unsigned long lower_page_index, int byte_offset, | |
552 | int region_bytes) | |
553 | { | |
554 | int rc = 0; | |
555 | ||
9d8b8ce5 MH |
556 | *lower_page = grab_cache_page(lower_inode->i_mapping, lower_page_index); |
557 | if (!(*lower_page)) { | |
558 | rc = -EINVAL; | |
559 | ecryptfs_printk(KERN_ERR, "Error attempting to grab " | |
237fead6 MH |
560 | "lower page with index [0x%.16x]\n", |
561 | lower_page_index); | |
562 | goto out; | |
563 | } | |
564 | rc = lower_inode->i_mapping->a_ops->prepare_write(lower_file, | |
565 | (*lower_page), | |
566 | byte_offset, | |
567 | region_bytes); | |
568 | if (rc) { | |
569 | ecryptfs_printk(KERN_ERR, "prepare_write for " | |
570 | "lower_page_index = [0x%.16x] failed; rc = " | |
571 | "[%d]\n", lower_page_index, rc); | |
572 | } | |
573 | out: | |
574 | if (rc && (*lower_page)) { | |
9d8b8ce5 | 575 | ecryptfs_release_lower_page(*lower_page); |
237fead6 MH |
576 | (*lower_page) = NULL; |
577 | } | |
578 | return rc; | |
579 | } | |
580 | ||
581 | /** | |
582 | * ecryptfs_commit_lower_page | |
583 | * | |
584 | * Returns zero on success; non-zero on error | |
585 | */ | |
586 | int | |
587 | ecryptfs_commit_lower_page(struct page *lower_page, struct inode *lower_inode, | |
588 | struct file *lower_file, int byte_offset, | |
589 | int region_size) | |
590 | { | |
591 | int rc = 0; | |
592 | ||
593 | rc = lower_inode->i_mapping->a_ops->commit_write( | |
594 | lower_file, lower_page, byte_offset, region_size); | |
595 | if (rc < 0) { | |
596 | ecryptfs_printk(KERN_ERR, | |
597 | "Error committing write; rc = [%d]\n", rc); | |
598 | } else | |
599 | rc = 0; | |
9d8b8ce5 | 600 | ecryptfs_release_lower_page(lower_page); |
237fead6 MH |
601 | return rc; |
602 | } | |
603 | ||
604 | /** | |
605 | * ecryptfs_copy_page_to_lower | |
606 | * | |
607 | * Used for plaintext pass-through; no page index interpolation | |
608 | * required. | |
609 | */ | |
610 | int ecryptfs_copy_page_to_lower(struct page *page, struct inode *lower_inode, | |
611 | struct file *lower_file) | |
612 | { | |
613 | int rc = 0; | |
614 | struct page *lower_page; | |
615 | ||
616 | rc = ecryptfs_get_lower_page(&lower_page, lower_inode, lower_file, | |
617 | page->index, 0, PAGE_CACHE_SIZE); | |
618 | if (rc) { | |
619 | ecryptfs_printk(KERN_ERR, "Error attempting to get page " | |
620 | "at index [0x%.16x]\n", page->index); | |
621 | goto out; | |
622 | } | |
623 | /* TODO: aops */ | |
624 | memcpy((char *)page_address(lower_page), page_address(page), | |
625 | PAGE_CACHE_SIZE); | |
626 | rc = ecryptfs_commit_lower_page(lower_page, lower_inode, lower_file, | |
627 | 0, PAGE_CACHE_SIZE); | |
628 | if (rc) | |
629 | ecryptfs_printk(KERN_ERR, "Error attempting to commit page " | |
630 | "at index [0x%.16x]\n", page->index); | |
631 | out: | |
632 | return rc; | |
633 | } | |
634 | ||
dd2a3b7a MH |
635 | struct kmem_cache *ecryptfs_xattr_cache; |
636 | ||
237fead6 MH |
637 | /** |
638 | * ecryptfs_commit_write | |
639 | * @file: The eCryptfs file object | |
640 | * @page: The eCryptfs page | |
641 | * @from: Ignored (we rotate the page IV on each write) | |
642 | * @to: Ignored | |
643 | * | |
644 | * This is where we encrypt the data and pass the encrypted data to | |
645 | * the lower filesystem. In OpenPGP-compatible mode, we operate on | |
646 | * entire underlying packets. | |
647 | */ | |
648 | static int ecryptfs_commit_write(struct file *file, struct page *page, | |
649 | unsigned from, unsigned to) | |
650 | { | |
651 | struct ecryptfs_page_crypt_context ctx; | |
652 | loff_t pos; | |
653 | struct inode *inode; | |
654 | struct inode *lower_inode; | |
655 | struct file *lower_file; | |
656 | struct ecryptfs_crypt_stat *crypt_stat; | |
657 | int rc; | |
658 | ||
659 | inode = page->mapping->host; | |
660 | lower_inode = ecryptfs_inode_to_lower(inode); | |
661 | lower_file = ecryptfs_file_to_lower(file); | |
662 | mutex_lock(&lower_inode->i_mutex); | |
bd243a4b JJS |
663 | crypt_stat = &ecryptfs_inode_to_private(file->f_path.dentry->d_inode) |
664 | ->crypt_stat; | |
e2bd99ec | 665 | if (crypt_stat->flags & ECRYPTFS_NEW_FILE) { |
237fead6 MH |
666 | ecryptfs_printk(KERN_DEBUG, "ECRYPTFS_NEW_FILE flag set in " |
667 | "crypt_stat at memory location [%p]\n", crypt_stat); | |
e2bd99ec | 668 | crypt_stat->flags &= ~(ECRYPTFS_NEW_FILE); |
237fead6 MH |
669 | } else |
670 | ecryptfs_printk(KERN_DEBUG, "Not a new file\n"); | |
671 | ecryptfs_printk(KERN_DEBUG, "Calling fill_zeros_to_end_of_page" | |
672 | "(page w/ index = [0x%.16x], to = [%d])\n", page->index, | |
673 | to); | |
674 | rc = fill_zeros_to_end_of_page(page, to); | |
675 | if (rc) { | |
676 | ecryptfs_printk(KERN_WARNING, "Error attempting to fill " | |
677 | "zeros in page with index = [0x%.16x]\n", | |
678 | page->index); | |
679 | goto out; | |
680 | } | |
681 | ctx.page = page; | |
682 | ctx.mode = ECRYPTFS_PREPARE_COMMIT_MODE; | |
683 | ctx.param.lower_file = lower_file; | |
684 | rc = ecryptfs_encrypt_page(&ctx); | |
685 | if (rc) { | |
686 | ecryptfs_printk(KERN_WARNING, "Error encrypting page (upper " | |
687 | "index [0x%.16x])\n", page->index); | |
688 | goto out; | |
689 | } | |
237fead6 MH |
690 | inode->i_blocks = lower_inode->i_blocks; |
691 | pos = (page->index << PAGE_CACHE_SHIFT) + to; | |
692 | if (pos > i_size_read(inode)) { | |
693 | i_size_write(inode, pos); | |
694 | ecryptfs_printk(KERN_DEBUG, "Expanded file size to " | |
695 | "[0x%.16x]\n", i_size_read(inode)); | |
696 | } | |
dd2a3b7a MH |
697 | rc = ecryptfs_write_inode_size_to_metadata(lower_file, lower_inode, |
698 | inode, file->f_dentry, | |
699 | ECRYPTFS_LOWER_I_MUTEX_HELD); | |
700 | if (rc) | |
701 | printk(KERN_ERR "Error writing inode size to metadata; " | |
702 | "rc = [%d]\n", rc); | |
237fead6 MH |
703 | lower_inode->i_mtime = lower_inode->i_ctime = CURRENT_TIME; |
704 | mark_inode_dirty_sync(inode); | |
705 | out: | |
237fead6 MH |
706 | if (rc < 0) |
707 | ClearPageUptodate(page); | |
708 | else | |
709 | SetPageUptodate(page); | |
710 | mutex_unlock(&lower_inode->i_mutex); | |
711 | return rc; | |
712 | } | |
713 | ||
714 | /** | |
715 | * write_zeros | |
716 | * @file: The ecryptfs file | |
717 | * @index: The index in which we are writing | |
718 | * @start: The position after the last block of data | |
719 | * @num_zeros: The number of zeros to write | |
720 | * | |
721 | * Write a specified number of zero's to a page. | |
722 | * | |
723 | * (start + num_zeros) must be less than or equal to PAGE_CACHE_SIZE | |
724 | */ | |
725 | static | |
726 | int write_zeros(struct file *file, pgoff_t index, int start, int num_zeros) | |
727 | { | |
728 | int rc = 0; | |
729 | struct page *tmp_page; | |
9d8b8ce5 | 730 | char *tmp_page_virt; |
237fead6 MH |
731 | |
732 | tmp_page = ecryptfs_get1page(file, index); | |
733 | if (IS_ERR(tmp_page)) { | |
734 | ecryptfs_printk(KERN_ERR, "Error getting page at index " | |
735 | "[0x%.16x]\n", index); | |
736 | rc = PTR_ERR(tmp_page); | |
737 | goto out; | |
738 | } | |
237fead6 MH |
739 | rc = ecryptfs_prepare_write(file, tmp_page, start, start + num_zeros); |
740 | if (rc) { | |
741 | ecryptfs_printk(KERN_ERR, "Error preparing to write zero's " | |
742 | "to remainder of page at index [0x%.16x]\n", | |
743 | index); | |
237fead6 MH |
744 | page_cache_release(tmp_page); |
745 | goto out; | |
746 | } | |
9d8b8ce5 MH |
747 | tmp_page_virt = kmap_atomic(tmp_page, KM_USER0); |
748 | memset(((char *)tmp_page_virt + start), 0, num_zeros); | |
749 | kunmap_atomic(tmp_page_virt, KM_USER0); | |
0a9ac382 | 750 | flush_dcache_page(tmp_page); |
237fead6 MH |
751 | rc = ecryptfs_commit_write(file, tmp_page, start, start + num_zeros); |
752 | if (rc < 0) { | |
753 | ecryptfs_printk(KERN_ERR, "Error attempting to write zero's " | |
754 | "to remainder of page at index [0x%.16x]\n", | |
755 | index); | |
237fead6 MH |
756 | page_cache_release(tmp_page); |
757 | goto out; | |
758 | } | |
759 | rc = 0; | |
237fead6 MH |
760 | page_cache_release(tmp_page); |
761 | out: | |
762 | return rc; | |
763 | } | |
764 | ||
765 | static sector_t ecryptfs_bmap(struct address_space *mapping, sector_t block) | |
766 | { | |
767 | int rc = 0; | |
768 | struct inode *inode; | |
769 | struct inode *lower_inode; | |
770 | ||
771 | inode = (struct inode *)mapping->host; | |
772 | lower_inode = ecryptfs_inode_to_lower(inode); | |
773 | if (lower_inode->i_mapping->a_ops->bmap) | |
774 | rc = lower_inode->i_mapping->a_ops->bmap(lower_inode->i_mapping, | |
775 | block); | |
776 | return rc; | |
777 | } | |
778 | ||
779 | static void ecryptfs_sync_page(struct page *page) | |
780 | { | |
781 | struct inode *inode; | |
782 | struct inode *lower_inode; | |
783 | struct page *lower_page; | |
784 | ||
785 | inode = page->mapping->host; | |
786 | lower_inode = ecryptfs_inode_to_lower(inode); | |
787 | /* NOTE: Recently swapped with grab_cache_page(), since | |
788 | * sync_page() just makes sure that pending I/O gets done. */ | |
789 | lower_page = find_lock_page(lower_inode->i_mapping, page->index); | |
790 | if (!lower_page) { | |
791 | ecryptfs_printk(KERN_DEBUG, "find_lock_page failed\n"); | |
792 | return; | |
793 | } | |
794 | lower_page->mapping->a_ops->sync_page(lower_page); | |
795 | ecryptfs_printk(KERN_DEBUG, "Unlocking page with index = [0x%.16x]\n", | |
796 | lower_page->index); | |
797 | unlock_page(lower_page); | |
798 | page_cache_release(lower_page); | |
799 | } | |
800 | ||
801 | struct address_space_operations ecryptfs_aops = { | |
802 | .writepage = ecryptfs_writepage, | |
803 | .readpage = ecryptfs_readpage, | |
804 | .prepare_write = ecryptfs_prepare_write, | |
805 | .commit_write = ecryptfs_commit_write, | |
806 | .bmap = ecryptfs_bmap, | |
807 | .sync_page = ecryptfs_sync_page, | |
808 | }; |