KVM: svm: init cr0 with the wp bit set
[linux-2.6] / fs / ecryptfs / mmap.c
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
9  * Copyright (C) 2004-2007 International Business Machines Corp.
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
54         dentry = file->f_path.dentry;
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;
87         struct dentry *dentry = file->f_path.dentry;
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
221         dentry = file->f_path.dentry;
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 = kmap_atomic(page, KM_USER0);
238         lower_page_data = kmap_atomic(lower_page, KM_USER1);
239         memcpy(page_data, lower_page_data, PAGE_CACHE_SIZE);
240         kunmap_atomic(lower_page_data, KM_USER1);
241         kunmap_atomic(page_data, KM_USER0);
242         flush_dcache_page(page);
243         rc = 0;
244 out:
245         if (likely(lower_page))
246                 page_cache_release(lower_page);
247         if (rc == 0)
248                 SetPageUptodate(page);
249         else
250                 ClearPageUptodate(page);
251         return rc;
252 }
253 /**
254  *   Header Extent:
255  *     Octets 0-7:        Unencrypted file size (big-endian)
256  *     Octets 8-15:       eCryptfs special marker
257  *     Octets 16-19:      Flags
258  *      Octet 16:         File format version number (between 0 and 255)
259  *      Octets 17-18:     Reserved
260  *      Octet 19:         Bit 1 (lsb): Reserved
261  *                        Bit 2: Encrypted?
262  *                        Bits 3-8: Reserved
263  *     Octets 20-23:      Header extent size (big-endian)
264  *     Octets 24-25:      Number of header extents at front of file
265  *                        (big-endian)
266  *     Octet  26:         Begin RFC 2440 authentication token packet set
267  */
268 static void set_header_info(char *page_virt,
269                             struct ecryptfs_crypt_stat *crypt_stat)
270 {
271         size_t written;
272         int save_num_header_extents_at_front =
273                 crypt_stat->num_header_extents_at_front;
274
275         crypt_stat->num_header_extents_at_front = 1;
276         ecryptfs_write_header_metadata(page_virt + 20, crypt_stat, &written);
277         crypt_stat->num_header_extents_at_front =
278                 save_num_header_extents_at_front;
279 }
280
281 /**
282  * ecryptfs_readpage
283  * @file: This is an ecryptfs file
284  * @page: ecryptfs associated page to stick the read data into
285  *
286  * Read in a page, decrypting if necessary.
287  *
288  * Returns zero on success; non-zero on error.
289  */
290 static int ecryptfs_readpage(struct file *file, struct page *page)
291 {
292         int rc = 0;
293         struct ecryptfs_crypt_stat *crypt_stat;
294
295         BUG_ON(!(file && file->f_path.dentry && file->f_path.dentry->d_inode));
296         crypt_stat = &ecryptfs_inode_to_private(file->f_path.dentry->d_inode)
297                         ->crypt_stat;
298         if (!crypt_stat
299             || !(crypt_stat->flags & ECRYPTFS_ENCRYPTED)
300             || (crypt_stat->flags & ECRYPTFS_NEW_FILE)) {
301                 ecryptfs_printk(KERN_DEBUG,
302                                 "Passing through unencrypted page\n");
303                 rc = ecryptfs_do_readpage(file, page, page->index);
304                 if (rc) {
305                         ecryptfs_printk(KERN_ERR, "Error reading page; rc = "
306                                         "[%d]\n", rc);
307                         goto out;
308                 }
309         } else if (crypt_stat->flags & ECRYPTFS_VIEW_AS_ENCRYPTED) {
310                 if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR) {
311                         int num_pages_in_header_region =
312                                 (crypt_stat->header_extent_size
313                                  / PAGE_CACHE_SIZE);
314
315                         if (page->index < num_pages_in_header_region) {
316                                 char *page_virt;
317
318                                 page_virt = kmap_atomic(page, KM_USER0);
319                                 memset(page_virt, 0, PAGE_CACHE_SIZE);
320                                 if (page->index == 0) {
321                                         rc = ecryptfs_read_xattr_region(
322                                                 page_virt, file->f_path.dentry);
323                                         set_header_info(page_virt, crypt_stat);
324                                 }
325                                 kunmap_atomic(page_virt, KM_USER0);
326                                 flush_dcache_page(page);
327                                 if (rc) {
328                                         printk(KERN_ERR "Error reading xattr "
329                                                "region\n");
330                                         goto out;
331                                 }
332                         } else {
333                                 rc = ecryptfs_do_readpage(
334                                         file, page,
335                                         (page->index
336                                          - num_pages_in_header_region));
337                                 if (rc) {
338                                         printk(KERN_ERR "Error reading page; "
339                                                "rc = [%d]\n", rc);
340                                         goto out;
341                                 }
342                         }
343                 } else {
344                         rc = ecryptfs_do_readpage(file, page, page->index);
345                         if (rc) {
346                                 printk(KERN_ERR "Error reading page; rc = "
347                                        "[%d]\n", rc);
348                                 goto out;
349                         }
350                 }
351         } else {
352                 rc = ecryptfs_decrypt_page(file, page);
353                 if (rc) {
354                         ecryptfs_printk(KERN_ERR, "Error decrypting page; "
355                                         "rc = [%d]\n", rc);
356                         goto out;
357                 }
358         }
359         SetPageUptodate(page);
360 out:
361         if (rc)
362                 ClearPageUptodate(page);
363         ecryptfs_printk(KERN_DEBUG, "Unlocking page with index = [0x%.16x]\n",
364                         page->index);
365         unlock_page(page);
366         return rc;
367 }
368
369 /**
370  * Called with lower inode mutex held.
371  */
372 static int fill_zeros_to_end_of_page(struct page *page, unsigned int to)
373 {
374         struct inode *inode = page->mapping->host;
375         int end_byte_in_page;
376         char *page_virt;
377
378         if ((i_size_read(inode) / PAGE_CACHE_SIZE) != page->index)
379                 goto out;
380         end_byte_in_page = i_size_read(inode) % PAGE_CACHE_SIZE;
381         if (to > end_byte_in_page)
382                 end_byte_in_page = to;
383         page_virt = kmap_atomic(page, KM_USER0);
384         memset((page_virt + end_byte_in_page), 0,
385                (PAGE_CACHE_SIZE - end_byte_in_page));
386         kunmap_atomic(page_virt, KM_USER0);
387         flush_dcache_page(page);
388 out:
389         return 0;
390 }
391
392 static int ecryptfs_prepare_write(struct file *file, struct page *page,
393                                   unsigned from, unsigned to)
394 {
395         int rc = 0;
396
397         if (from == 0 && to == PAGE_CACHE_SIZE)
398                 goto out;       /* If we are writing a full page, it will be
399                                    up to date. */
400         if (!PageUptodate(page))
401                 rc = ecryptfs_do_readpage(file, page, page->index);
402 out:
403         return rc;
404 }
405
406 int ecryptfs_writepage_and_release_lower_page(struct page *lower_page,
407                                               struct inode *lower_inode,
408                                               struct writeback_control *wbc)
409 {
410         int rc = 0;
411
412         rc = lower_inode->i_mapping->a_ops->writepage(lower_page, wbc);
413         if (rc) {
414                 ecryptfs_printk(KERN_ERR, "Error calling lower writepage(); "
415                                 "rc = [%d]\n", rc);
416                 goto out;
417         }
418         lower_inode->i_mtime = lower_inode->i_ctime = CURRENT_TIME;
419         page_cache_release(lower_page);
420 out:
421         return rc;
422 }
423
424 static
425 void ecryptfs_release_lower_page(struct page *lower_page, int page_locked)
426 {
427         if (page_locked)
428                 unlock_page(lower_page);
429         page_cache_release(lower_page);
430 }
431
432 /**
433  * ecryptfs_write_inode_size_to_header
434  *
435  * Writes the lower file size to the first 8 bytes of the header.
436  *
437  * Returns zero on success; non-zero on error.
438  */
439 static int ecryptfs_write_inode_size_to_header(struct file *lower_file,
440                                                struct inode *lower_inode,
441                                                struct inode *inode)
442 {
443         int rc = 0;
444         struct page *header_page;
445         char *header_virt;
446         const struct address_space_operations *lower_a_ops;
447         u64 file_size;
448
449         header_page = grab_cache_page(lower_inode->i_mapping, 0);
450         if (!header_page) {
451                 ecryptfs_printk(KERN_ERR, "grab_cache_page for "
452                                 "lower_page_index 0 failed\n");
453                 rc = -EINVAL;
454                 goto out;
455         }
456         lower_a_ops = lower_inode->i_mapping->a_ops;
457         rc = lower_a_ops->prepare_write(lower_file, header_page, 0, 8);
458         if (rc) {
459                 if (rc == AOP_TRUNCATED_PAGE)
460                         ecryptfs_release_lower_page(header_page, 0);
461                 else
462                         ecryptfs_release_lower_page(header_page, 1);
463                 goto out;
464         }
465         file_size = (u64)i_size_read(inode);
466         ecryptfs_printk(KERN_DEBUG, "Writing size: [0x%.16x]\n", file_size);
467         file_size = cpu_to_be64(file_size);
468         header_virt = kmap_atomic(header_page, KM_USER0);
469         memcpy(header_virt, &file_size, sizeof(u64));
470         kunmap_atomic(header_virt, KM_USER0);
471         flush_dcache_page(header_page);
472         rc = lower_a_ops->commit_write(lower_file, header_page, 0, 8);
473         if (rc < 0)
474                 ecryptfs_printk(KERN_ERR, "Error commiting header page "
475                                 "write\n");
476         if (rc == AOP_TRUNCATED_PAGE)
477                 ecryptfs_release_lower_page(header_page, 0);
478         else
479                 ecryptfs_release_lower_page(header_page, 1);
480         lower_inode->i_mtime = lower_inode->i_ctime = CURRENT_TIME;
481         mark_inode_dirty_sync(inode);
482 out:
483         return rc;
484 }
485
486 static int ecryptfs_write_inode_size_to_xattr(struct inode *lower_inode,
487                                               struct inode *inode,
488                                               struct dentry *ecryptfs_dentry,
489                                               int lower_i_mutex_held)
490 {
491         ssize_t size;
492         void *xattr_virt;
493         struct dentry *lower_dentry;
494         u64 file_size;
495         int rc;
496
497         xattr_virt = kmem_cache_alloc(ecryptfs_xattr_cache, GFP_KERNEL);
498         if (!xattr_virt) {
499                 printk(KERN_ERR "Out of memory whilst attempting to write "
500                        "inode size to xattr\n");
501                 rc = -ENOMEM;
502                 goto out;
503         }
504         lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
505         if (!lower_dentry->d_inode->i_op->getxattr) {
506                 printk(KERN_WARNING
507                        "No support for setting xattr in lower filesystem\n");
508                 rc = -ENOSYS;
509                 kmem_cache_free(ecryptfs_xattr_cache, xattr_virt);
510                 goto out;
511         }
512         if (!lower_i_mutex_held)
513                 mutex_lock(&lower_dentry->d_inode->i_mutex);
514         size = lower_dentry->d_inode->i_op->getxattr(lower_dentry,
515                                                      ECRYPTFS_XATTR_NAME,
516                                                      xattr_virt,
517                                                      PAGE_CACHE_SIZE);
518         if (!lower_i_mutex_held)
519                 mutex_unlock(&lower_dentry->d_inode->i_mutex);
520         if (size < 0)
521                 size = 8;
522         file_size = (u64)i_size_read(inode);
523         file_size = cpu_to_be64(file_size);
524         memcpy(xattr_virt, &file_size, sizeof(u64));
525         if (!lower_i_mutex_held)
526                 mutex_lock(&lower_dentry->d_inode->i_mutex);
527         rc = lower_dentry->d_inode->i_op->setxattr(lower_dentry,
528                                                    ECRYPTFS_XATTR_NAME,
529                                                    xattr_virt, size, 0);
530         if (!lower_i_mutex_held)
531                 mutex_unlock(&lower_dentry->d_inode->i_mutex);
532         if (rc)
533                 printk(KERN_ERR "Error whilst attempting to write inode size "
534                        "to lower file xattr; rc = [%d]\n", rc);
535         kmem_cache_free(ecryptfs_xattr_cache, xattr_virt);
536 out:
537         return rc;
538 }
539
540 int
541 ecryptfs_write_inode_size_to_metadata(struct file *lower_file,
542                                       struct inode *lower_inode,
543                                       struct inode *inode,
544                                       struct dentry *ecryptfs_dentry,
545                                       int lower_i_mutex_held)
546 {
547         struct ecryptfs_crypt_stat *crypt_stat;
548
549         crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
550         if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
551                 return ecryptfs_write_inode_size_to_xattr(lower_inode, inode,
552                                                           ecryptfs_dentry,
553                                                           lower_i_mutex_held);
554         else
555                 return ecryptfs_write_inode_size_to_header(lower_file,
556                                                            lower_inode,
557                                                            inode);
558 }
559
560 int ecryptfs_get_lower_page(struct page **lower_page, struct inode *lower_inode,
561                             struct file *lower_file,
562                             unsigned long lower_page_index, int byte_offset,
563                             int region_bytes)
564 {
565         int rc = 0;
566
567         *lower_page = grab_cache_page(lower_inode->i_mapping, lower_page_index);
568         if (!(*lower_page)) {
569                 rc = -EINVAL;
570                 ecryptfs_printk(KERN_ERR, "Error attempting to grab "
571                                 "lower page with index [0x%.16x]\n",
572                                 lower_page_index);
573                 goto out;
574         }
575         rc = lower_inode->i_mapping->a_ops->prepare_write(lower_file,
576                                                           (*lower_page),
577                                                           byte_offset,
578                                                           region_bytes);
579         if (rc) {
580                 ecryptfs_printk(KERN_ERR, "prepare_write for "
581                                 "lower_page_index = [0x%.16x] failed; rc = "
582                                 "[%d]\n", lower_page_index, rc);
583         }
584 out:
585         if (rc && (*lower_page)) {
586                 if (rc == AOP_TRUNCATED_PAGE)
587                         ecryptfs_release_lower_page(*lower_page, 0);
588                 else
589                         ecryptfs_release_lower_page(*lower_page, 1);
590                 (*lower_page) = NULL;
591         }
592         return rc;
593 }
594
595 /**
596  * ecryptfs_commit_lower_page
597  *
598  * Returns zero on success; non-zero on error
599  */
600 int
601 ecryptfs_commit_lower_page(struct page *lower_page, struct inode *lower_inode,
602                            struct file *lower_file, int byte_offset,
603                            int region_size)
604 {
605         int page_locked = 1;
606         int rc = 0;
607
608         rc = lower_inode->i_mapping->a_ops->commit_write(
609                 lower_file, lower_page, byte_offset, region_size);
610         if (rc == AOP_TRUNCATED_PAGE)
611                 page_locked = 0;
612         if (rc < 0) {
613                 ecryptfs_printk(KERN_ERR,
614                                 "Error committing write; rc = [%d]\n", rc);
615         } else
616                 rc = 0;
617         ecryptfs_release_lower_page(lower_page, page_locked);
618         return rc;
619 }
620
621 /**
622  * ecryptfs_copy_page_to_lower
623  *
624  * Used for plaintext pass-through; no page index interpolation
625  * required.
626  */
627 int ecryptfs_copy_page_to_lower(struct page *page, struct inode *lower_inode,
628                                 struct file *lower_file)
629 {
630         int rc = 0;
631         struct page *lower_page;
632
633         rc = ecryptfs_get_lower_page(&lower_page, lower_inode, lower_file,
634                                      page->index, 0, PAGE_CACHE_SIZE);
635         if (rc) {
636                 ecryptfs_printk(KERN_ERR, "Error attempting to get page "
637                                 "at index [0x%.16x]\n", page->index);
638                 goto out;
639         }
640         /* TODO: aops */
641         memcpy((char *)page_address(lower_page), page_address(page),
642                PAGE_CACHE_SIZE);
643         rc = ecryptfs_commit_lower_page(lower_page, lower_inode, lower_file,
644                                         0, PAGE_CACHE_SIZE);
645         if (rc)
646                 ecryptfs_printk(KERN_ERR, "Error attempting to commit page "
647                                 "at index [0x%.16x]\n", page->index);
648 out:
649         return rc;
650 }
651
652 struct kmem_cache *ecryptfs_xattr_cache;
653
654 /**
655  * ecryptfs_commit_write
656  * @file: The eCryptfs file object
657  * @page: The eCryptfs page
658  * @from: Ignored (we rotate the page IV on each write)
659  * @to: Ignored
660  *
661  * This is where we encrypt the data and pass the encrypted data to
662  * the lower filesystem.  In OpenPGP-compatible mode, we operate on
663  * entire underlying packets.
664  */
665 static int ecryptfs_commit_write(struct file *file, struct page *page,
666                                  unsigned from, unsigned to)
667 {
668         struct ecryptfs_page_crypt_context ctx;
669         loff_t pos;
670         struct inode *inode;
671         struct inode *lower_inode;
672         struct file *lower_file;
673         struct ecryptfs_crypt_stat *crypt_stat;
674         int rc;
675
676         inode = page->mapping->host;
677         lower_inode = ecryptfs_inode_to_lower(inode);
678         lower_file = ecryptfs_file_to_lower(file);
679         mutex_lock(&lower_inode->i_mutex);
680         crypt_stat = &ecryptfs_inode_to_private(file->f_path.dentry->d_inode)
681                                 ->crypt_stat;
682         if (crypt_stat->flags & ECRYPTFS_NEW_FILE) {
683                 ecryptfs_printk(KERN_DEBUG, "ECRYPTFS_NEW_FILE flag set in "
684                         "crypt_stat at memory location [%p]\n", crypt_stat);
685                 crypt_stat->flags &= ~(ECRYPTFS_NEW_FILE);
686         } else
687                 ecryptfs_printk(KERN_DEBUG, "Not a new file\n");
688         ecryptfs_printk(KERN_DEBUG, "Calling fill_zeros_to_end_of_page"
689                         "(page w/ index = [0x%.16x], to = [%d])\n", page->index,
690                         to);
691         rc = fill_zeros_to_end_of_page(page, to);
692         if (rc) {
693                 ecryptfs_printk(KERN_WARNING, "Error attempting to fill "
694                                 "zeros in page with index = [0x%.16x]\n",
695                                 page->index);
696                 goto out;
697         }
698         ctx.page = page;
699         ctx.mode = ECRYPTFS_PREPARE_COMMIT_MODE;
700         ctx.param.lower_file = lower_file;
701         rc = ecryptfs_encrypt_page(&ctx);
702         if (rc) {
703                 ecryptfs_printk(KERN_WARNING, "Error encrypting page (upper "
704                                 "index [0x%.16x])\n", page->index);
705                 goto out;
706         }
707         inode->i_blocks = lower_inode->i_blocks;
708         pos = (page->index << PAGE_CACHE_SHIFT) + to;
709         if (pos > i_size_read(inode)) {
710                 i_size_write(inode, pos);
711                 ecryptfs_printk(KERN_DEBUG, "Expanded file size to "
712                                 "[0x%.16x]\n", i_size_read(inode));
713         }
714         rc = ecryptfs_write_inode_size_to_metadata(lower_file, lower_inode,
715                                                    inode, file->f_dentry,
716                                                    ECRYPTFS_LOWER_I_MUTEX_HELD);
717         if (rc)
718                 printk(KERN_ERR "Error writing inode size to metadata; "
719                        "rc = [%d]\n", rc);
720         lower_inode->i_mtime = lower_inode->i_ctime = CURRENT_TIME;
721         mark_inode_dirty_sync(inode);
722 out:
723         if (rc < 0)
724                 ClearPageUptodate(page);
725         else
726                 SetPageUptodate(page);
727         mutex_unlock(&lower_inode->i_mutex);
728         return rc;
729 }
730
731 /**
732  * write_zeros
733  * @file: The ecryptfs file
734  * @index: The index in which we are writing
735  * @start: The position after the last block of data
736  * @num_zeros: The number of zeros to write
737  *
738  * Write a specified number of zero's to a page.
739  *
740  * (start + num_zeros) must be less than or equal to PAGE_CACHE_SIZE
741  */
742 static
743 int write_zeros(struct file *file, pgoff_t index, int start, int num_zeros)
744 {
745         int rc = 0;
746         struct page *tmp_page;
747         char *tmp_page_virt;
748
749         tmp_page = ecryptfs_get1page(file, index);
750         if (IS_ERR(tmp_page)) {
751                 ecryptfs_printk(KERN_ERR, "Error getting page at index "
752                                 "[0x%.16x]\n", index);
753                 rc = PTR_ERR(tmp_page);
754                 goto out;
755         }
756         rc = ecryptfs_prepare_write(file, tmp_page, start, start + num_zeros);
757         if (rc) {
758                 ecryptfs_printk(KERN_ERR, "Error preparing to write zero's "
759                                 "to remainder of page at index [0x%.16x]\n",
760                                 index);
761                 page_cache_release(tmp_page);
762                 goto out;
763         }
764         tmp_page_virt = kmap_atomic(tmp_page, KM_USER0);
765         memset(((char *)tmp_page_virt + start), 0, num_zeros);
766         kunmap_atomic(tmp_page_virt, KM_USER0);
767         flush_dcache_page(tmp_page);
768         rc = ecryptfs_commit_write(file, tmp_page, start, start + num_zeros);
769         if (rc < 0) {
770                 ecryptfs_printk(KERN_ERR, "Error attempting to write zero's "
771                                 "to remainder of page at index [0x%.16x]\n",
772                                 index);
773                 page_cache_release(tmp_page);
774                 goto out;
775         }
776         rc = 0;
777         page_cache_release(tmp_page);
778 out:
779         return rc;
780 }
781
782 static sector_t ecryptfs_bmap(struct address_space *mapping, sector_t block)
783 {
784         int rc = 0;
785         struct inode *inode;
786         struct inode *lower_inode;
787
788         inode = (struct inode *)mapping->host;
789         lower_inode = ecryptfs_inode_to_lower(inode);
790         if (lower_inode->i_mapping->a_ops->bmap)
791                 rc = lower_inode->i_mapping->a_ops->bmap(lower_inode->i_mapping,
792                                                          block);
793         return rc;
794 }
795
796 static void ecryptfs_sync_page(struct page *page)
797 {
798         struct inode *inode;
799         struct inode *lower_inode;
800         struct page *lower_page;
801
802         inode = page->mapping->host;
803         lower_inode = ecryptfs_inode_to_lower(inode);
804         /* NOTE: Recently swapped with grab_cache_page(), since
805          * sync_page() just makes sure that pending I/O gets done. */
806         lower_page = find_lock_page(lower_inode->i_mapping, page->index);
807         if (!lower_page) {
808                 ecryptfs_printk(KERN_DEBUG, "find_lock_page failed\n");
809                 return;
810         }
811         lower_page->mapping->a_ops->sync_page(lower_page);
812         ecryptfs_printk(KERN_DEBUG, "Unlocking page with index = [0x%.16x]\n",
813                         lower_page->index);
814         unlock_page(lower_page);
815         page_cache_release(lower_page);
816 }
817
818 struct address_space_operations ecryptfs_aops = {
819         .writepage = ecryptfs_writepage,
820         .readpage = ecryptfs_readpage,
821         .prepare_write = ecryptfs_prepare_write,
822         .commit_write = ecryptfs_commit_write,
823         .bmap = ecryptfs_bmap,
824         .sync_page = ecryptfs_sync_page,
825 };