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Michael Halcrow237fead2006-10-04 02:16:22 -07001/**
2 * eCryptfs: Linux filesystem encryption layer
3 *
4 * Copyright (C) 1997-2004 Erez Zadok
5 * Copyright (C) 2001-2004 Stony Brook University
6 * Copyright (C) 2004-2006 International Business Machines Corp.
7 * Author(s): Michael A. Halcrow <mhalcrow@us.ibm.com>
8 * Michael C. Thompson <mcthomps@us.ibm.com>
9 *
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License as
12 * published by the Free Software Foundation; either version 2 of the
13 * License, or (at your option) any later version.
14 *
15 * This program is distributed in the hope that it will be useful, but
16 * WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
18 * General Public License for more details.
19 *
20 * You should have received a copy of the GNU General Public License
21 * along with this program; if not, write to the Free Software
22 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
23 * 02111-1307, USA.
24 */
25
26#include <linux/file.h>
27#include <linux/poll.h>
28#include <linux/mount.h>
29#include <linux/pagemap.h>
30#include <linux/security.h>
31#include <linux/smp_lock.h>
32#include <linux/compat.h>
Josef "Jeff" Sipek0cc72dc2006-12-08 02:36:31 -080033#include <linux/fs_stack.h>
Michael Halcrow237fead2006-10-04 02:16:22 -070034#include "ecryptfs_kernel.h"
35
36/**
37 * ecryptfs_llseek
38 * @file: File we are seeking in
39 * @offset: The offset to seek to
40 * @origin: 2 - offset from i_size; 1 - offset from f_pos
41 *
42 * Returns the position we have seeked to, or negative on error
43 */
44static loff_t ecryptfs_llseek(struct file *file, loff_t offset, int origin)
45{
46 loff_t rv;
47 loff_t new_end_pos;
48 int rc;
49 int expanding_file = 0;
50 struct inode *inode = file->f_mapping->host;
51
52 /* If our offset is past the end of our file, we're going to
53 * need to grow it so we have a valid length of 0's */
54 new_end_pos = offset;
55 switch (origin) {
56 case 2:
57 new_end_pos += i_size_read(inode);
58 expanding_file = 1;
59 break;
60 case 1:
61 new_end_pos += file->f_pos;
62 if (new_end_pos > i_size_read(inode)) {
63 ecryptfs_printk(KERN_DEBUG, "new_end_pos(=[0x%.16x]) "
64 "> i_size_read(inode)(=[0x%.16x])\n",
65 new_end_pos, i_size_read(inode));
66 expanding_file = 1;
67 }
68 break;
69 default:
70 if (new_end_pos > i_size_read(inode)) {
71 ecryptfs_printk(KERN_DEBUG, "new_end_pos(=[0x%.16x]) "
72 "> i_size_read(inode)(=[0x%.16x])\n",
73 new_end_pos, i_size_read(inode));
74 expanding_file = 1;
75 }
76 }
77 ecryptfs_printk(KERN_DEBUG, "new_end_pos = [0x%.16x]\n", new_end_pos);
78 if (expanding_file) {
Josef "Jeff" Sipekbd243a42006-12-08 02:36:48 -080079 rc = ecryptfs_truncate(file->f_path.dentry, new_end_pos);
Michael Halcrow237fead2006-10-04 02:16:22 -070080 if (rc) {
81 rv = rc;
82 ecryptfs_printk(KERN_ERR, "Error on attempt to "
83 "truncate to (higher) offset [0x%.16x];"
84 " rc = [%d]\n", new_end_pos, rc);
85 goto out;
86 }
87 }
88 rv = generic_file_llseek(file, offset, origin);
89out:
90 return rv;
91}
92
93/**
94 * ecryptfs_read_update_atime
95 *
96 * generic_file_read updates the atime of upper layer inode. But, it
97 * doesn't give us a chance to update the atime of the lower layer
98 * inode. This function is a wrapper to generic_file_read. It
99 * updates the atime of the lower level inode if generic_file_read
100 * returns without any errors. This is to be used only for file reads.
101 * The function to be used for directory reads is ecryptfs_read.
102 */
103static ssize_t ecryptfs_read_update_atime(struct kiocb *iocb,
104 const struct iovec *iov,
105 unsigned long nr_segs, loff_t pos)
106{
107 int rc;
108 struct dentry *lower_dentry;
109 struct vfsmount *lower_vfsmount;
110 struct file *file = iocb->ki_filp;
111
112 rc = generic_file_aio_read(iocb, iov, nr_segs, pos);
113 /*
114 * Even though this is a async interface, we need to wait
115 * for IO to finish to update atime
116 */
117 if (-EIOCBQUEUED == rc)
118 rc = wait_on_sync_kiocb(iocb);
119 if (rc >= 0) {
Josef "Jeff" Sipekbd243a42006-12-08 02:36:48 -0800120 lower_dentry = ecryptfs_dentry_to_lower(file->f_path.dentry);
121 lower_vfsmount = ecryptfs_dentry_to_lower_mnt(file->f_path.dentry);
Michael Halcrow237fead2006-10-04 02:16:22 -0700122 touch_atime(lower_vfsmount, lower_dentry);
123 }
124 return rc;
125}
126
127struct ecryptfs_getdents_callback {
128 void *dirent;
129 struct dentry *dentry;
130 filldir_t filldir;
131 int err;
132 int filldir_called;
133 int entries_written;
134};
135
136/* Inspired by generic filldir in fs/readir.c */
137static int
138ecryptfs_filldir(void *dirent, const char *name, int namelen, loff_t offset,
139 u64 ino, unsigned int d_type)
140{
141 struct ecryptfs_crypt_stat *crypt_stat;
142 struct ecryptfs_getdents_callback *buf =
143 (struct ecryptfs_getdents_callback *)dirent;
144 int rc;
145 int decoded_length;
146 char *decoded_name;
147
148 crypt_stat = ecryptfs_dentry_to_private(buf->dentry)->crypt_stat;
149 buf->filldir_called++;
150 decoded_length = ecryptfs_decode_filename(crypt_stat, name, namelen,
151 &decoded_name);
152 if (decoded_length < 0) {
153 rc = decoded_length;
154 goto out;
155 }
156 rc = buf->filldir(buf->dirent, decoded_name, decoded_length, offset,
157 ino, d_type);
158 kfree(decoded_name);
159 if (rc >= 0)
160 buf->entries_written++;
161out:
162 return rc;
163}
164
165/**
166 * ecryptfs_readdir
167 * @file: The ecryptfs file struct
168 * @dirent: Directory entry
169 * @filldir: The filldir callback function
170 */
171static int ecryptfs_readdir(struct file *file, void *dirent, filldir_t filldir)
172{
173 int rc;
174 struct file *lower_file;
175 struct inode *inode;
176 struct ecryptfs_getdents_callback buf;
177
178 lower_file = ecryptfs_file_to_lower(file);
179 lower_file->f_pos = file->f_pos;
Josef "Jeff" Sipekbd243a42006-12-08 02:36:48 -0800180 inode = file->f_path.dentry->d_inode;
Michael Halcrow237fead2006-10-04 02:16:22 -0700181 memset(&buf, 0, sizeof(buf));
182 buf.dirent = dirent;
Josef "Jeff" Sipekbd243a42006-12-08 02:36:48 -0800183 buf.dentry = file->f_path.dentry;
Michael Halcrow237fead2006-10-04 02:16:22 -0700184 buf.filldir = filldir;
185retry:
186 buf.filldir_called = 0;
187 buf.entries_written = 0;
188 buf.err = 0;
189 rc = vfs_readdir(lower_file, ecryptfs_filldir, (void *)&buf);
190 if (buf.err)
191 rc = buf.err;
192 if (buf.filldir_called && !buf.entries_written)
193 goto retry;
194 file->f_pos = lower_file->f_pos;
195 if (rc >= 0)
Josef "Jeff" Sipekbd243a42006-12-08 02:36:48 -0800196 fsstack_copy_attr_atime(inode, lower_file->f_path.dentry->d_inode);
Michael Halcrow237fead2006-10-04 02:16:22 -0700197 return rc;
198}
199
200struct kmem_cache *ecryptfs_file_info_cache;
201
Michael Halcrow7ff1d742006-10-30 22:07:19 -0800202int ecryptfs_open_lower_file(struct file **lower_file,
203 struct dentry *lower_dentry,
204 struct vfsmount *lower_mnt, int flags)
205{
206 int rc = 0;
207
208 dget(lower_dentry);
209 mntget(lower_mnt);
210 *lower_file = dentry_open(lower_dentry, lower_mnt, flags);
211 if (IS_ERR(*lower_file)) {
212 printk(KERN_ERR "Error opening lower file for lower_dentry "
213 "[0x%p], lower_mnt [0x%p], and flags [0x%x]\n",
214 lower_dentry, lower_mnt, flags);
215 rc = PTR_ERR(*lower_file);
216 *lower_file = NULL;
217 goto out;
218 }
219out:
220 return rc;
221}
222
223int ecryptfs_close_lower_file(struct file *lower_file)
224{
225 fput(lower_file);
226 return 0;
227}
228
Michael Halcrow237fead2006-10-04 02:16:22 -0700229/**
230 * ecryptfs_open
231 * @inode: inode speciying file to open
232 * @file: Structure to return filled in
233 *
234 * Opens the file specified by inode.
235 *
236 * Returns zero on success; non-zero otherwise
237 */
238static int ecryptfs_open(struct inode *inode, struct file *file)
239{
240 int rc = 0;
241 struct ecryptfs_crypt_stat *crypt_stat = NULL;
242 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
Josef "Jeff" Sipekbd243a42006-12-08 02:36:48 -0800243 struct dentry *ecryptfs_dentry = file->f_path.dentry;
Michael Halcrow237fead2006-10-04 02:16:22 -0700244 /* Private value of ecryptfs_dentry allocated in
245 * ecryptfs_lookup() */
246 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
247 struct inode *lower_inode = NULL;
248 struct file *lower_file = NULL;
249 struct vfsmount *lower_mnt;
250 struct ecryptfs_file_info *file_info;
251 int lower_flags;
252
253 /* Released in ecryptfs_release or end of function if failure */
Robert P. J. Dayc3762222007-02-10 01:45:03 -0800254 file_info = kmem_cache_zalloc(ecryptfs_file_info_cache, GFP_KERNEL);
Michael Halcrow237fead2006-10-04 02:16:22 -0700255 ecryptfs_set_file_private(file, file_info);
256 if (!file_info) {
257 ecryptfs_printk(KERN_ERR,
258 "Error attempting to allocate memory\n");
259 rc = -ENOMEM;
260 goto out;
261 }
Michael Halcrow237fead2006-10-04 02:16:22 -0700262 lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
263 crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
264 mount_crypt_stat = &ecryptfs_superblock_to_private(
265 ecryptfs_dentry->d_sb)->mount_crypt_stat;
266 mutex_lock(&crypt_stat->cs_mutex);
267 if (!ECRYPTFS_CHECK_FLAG(crypt_stat->flags, ECRYPTFS_POLICY_APPLIED)) {
268 ecryptfs_printk(KERN_DEBUG, "Setting flags for stat...\n");
269 /* Policy code enabled in future release */
270 ECRYPTFS_SET_FLAG(crypt_stat->flags, ECRYPTFS_POLICY_APPLIED);
271 ECRYPTFS_SET_FLAG(crypt_stat->flags, ECRYPTFS_ENCRYPTED);
272 }
273 mutex_unlock(&crypt_stat->cs_mutex);
Michael Halcrow237fead2006-10-04 02:16:22 -0700274 lower_flags = file->f_flags;
275 if ((lower_flags & O_ACCMODE) == O_WRONLY)
276 lower_flags = (lower_flags & O_ACCMODE) | O_RDWR;
277 if (file->f_flags & O_APPEND)
278 lower_flags &= ~O_APPEND;
279 lower_mnt = ecryptfs_dentry_to_lower_mnt(ecryptfs_dentry);
Michael Halcrow237fead2006-10-04 02:16:22 -0700280 /* Corresponding fput() in ecryptfs_release() */
Michael Halcrow7ff1d742006-10-30 22:07:19 -0800281 if ((rc = ecryptfs_open_lower_file(&lower_file, lower_dentry, lower_mnt,
282 lower_flags))) {
Michael Halcrow237fead2006-10-04 02:16:22 -0700283 ecryptfs_printk(KERN_ERR, "Error opening lower file\n");
284 goto out_puts;
285 }
286 ecryptfs_set_file_lower(file, lower_file);
287 /* Isn't this check the same as the one in lookup? */
288 lower_inode = lower_dentry->d_inode;
289 if (S_ISDIR(ecryptfs_dentry->d_inode->i_mode)) {
290 ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
291 ECRYPTFS_CLEAR_FLAG(crypt_stat->flags, ECRYPTFS_ENCRYPTED);
292 rc = 0;
293 goto out;
294 }
295 mutex_lock(&crypt_stat->cs_mutex);
296 if (i_size_read(lower_inode) < ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE) {
297 if (!(mount_crypt_stat->flags
298 & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) {
299 rc = -EIO;
300 printk(KERN_WARNING "Attempt to read file that is "
301 "not in a valid eCryptfs format, and plaintext "
302 "passthrough mode is not enabled; returning "
303 "-EIO\n");
304 mutex_unlock(&crypt_stat->cs_mutex);
305 goto out_puts;
306 }
307 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
308 rc = 0;
309 mutex_unlock(&crypt_stat->cs_mutex);
310 goto out;
311 } else if (!ECRYPTFS_CHECK_FLAG(crypt_stat->flags,
312 ECRYPTFS_POLICY_APPLIED)
313 || !ECRYPTFS_CHECK_FLAG(crypt_stat->flags,
314 ECRYPTFS_KEY_VALID)) {
315 rc = ecryptfs_read_headers(ecryptfs_dentry, lower_file);
316 if (rc) {
317 ecryptfs_printk(KERN_DEBUG,
318 "Valid headers not found\n");
319 if (!(mount_crypt_stat->flags
320 & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) {
321 rc = -EIO;
322 printk(KERN_WARNING "Attempt to read file that "
323 "is not in a valid eCryptfs format, "
324 "and plaintext passthrough mode is not "
325 "enabled; returning -EIO\n");
326 mutex_unlock(&crypt_stat->cs_mutex);
327 goto out_puts;
328 }
329 ECRYPTFS_CLEAR_FLAG(crypt_stat->flags,
330 ECRYPTFS_ENCRYPTED);
331 rc = 0;
332 mutex_unlock(&crypt_stat->cs_mutex);
333 goto out;
334 }
335 }
336 mutex_unlock(&crypt_stat->cs_mutex);
337 ecryptfs_printk(KERN_DEBUG, "inode w/ addr = [0x%p], i_ino = [0x%.16x] "
338 "size: [0x%.16x]\n", inode, inode->i_ino,
339 i_size_read(inode));
340 ecryptfs_set_file_lower(file, lower_file);
341 goto out;
342out_puts:
343 mntput(lower_mnt);
344 dput(lower_dentry);
345 kmem_cache_free(ecryptfs_file_info_cache,
346 ecryptfs_file_to_private(file));
347out:
348 return rc;
349}
350
351static int ecryptfs_flush(struct file *file, fl_owner_t td)
352{
353 int rc = 0;
354 struct file *lower_file = NULL;
355
356 lower_file = ecryptfs_file_to_lower(file);
357 if (lower_file->f_op && lower_file->f_op->flush)
358 rc = lower_file->f_op->flush(lower_file, td);
359 return rc;
360}
361
362static int ecryptfs_release(struct inode *inode, struct file *file)
363{
364 struct file *lower_file = ecryptfs_file_to_lower(file);
365 struct ecryptfs_file_info *file_info = ecryptfs_file_to_private(file);
366 struct inode *lower_inode = ecryptfs_inode_to_lower(inode);
Michael Halcrow7ff1d742006-10-30 22:07:19 -0800367 int rc;
Michael Halcrow237fead2006-10-04 02:16:22 -0700368
Michael Halcrow7ff1d742006-10-30 22:07:19 -0800369 if ((rc = ecryptfs_close_lower_file(lower_file))) {
370 printk(KERN_ERR "Error closing lower_file\n");
371 goto out;
372 }
Michael Halcrow237fead2006-10-04 02:16:22 -0700373 inode->i_blocks = lower_inode->i_blocks;
374 kmem_cache_free(ecryptfs_file_info_cache, file_info);
Michael Halcrow7ff1d742006-10-30 22:07:19 -0800375out:
376 return rc;
Michael Halcrow237fead2006-10-04 02:16:22 -0700377}
378
379static int
380ecryptfs_fsync(struct file *file, struct dentry *dentry, int datasync)
381{
382 struct file *lower_file = ecryptfs_file_to_lower(file);
383 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
384 struct inode *lower_inode = lower_dentry->d_inode;
385 int rc = -EINVAL;
386
387 if (lower_inode->i_fop->fsync) {
388 mutex_lock(&lower_inode->i_mutex);
389 rc = lower_inode->i_fop->fsync(lower_file, lower_dentry,
390 datasync);
391 mutex_unlock(&lower_inode->i_mutex);
392 }
393 return rc;
394}
395
396static int ecryptfs_fasync(int fd, struct file *file, int flag)
397{
398 int rc = 0;
399 struct file *lower_file = NULL;
400
401 lower_file = ecryptfs_file_to_lower(file);
402 if (lower_file->f_op && lower_file->f_op->fasync)
403 rc = lower_file->f_op->fasync(fd, lower_file, flag);
404 return rc;
405}
406
407static ssize_t ecryptfs_sendfile(struct file *file, loff_t * ppos,
408 size_t count, read_actor_t actor, void *target)
409{
410 struct file *lower_file = NULL;
411 int rc = -EINVAL;
412
413 lower_file = ecryptfs_file_to_lower(file);
414 if (lower_file->f_op && lower_file->f_op->sendfile)
415 rc = lower_file->f_op->sendfile(lower_file, ppos, count,
416 actor, target);
417
418 return rc;
419}
420
421static int ecryptfs_ioctl(struct inode *inode, struct file *file,
422 unsigned int cmd, unsigned long arg);
423
424const struct file_operations ecryptfs_dir_fops = {
425 .readdir = ecryptfs_readdir,
426 .ioctl = ecryptfs_ioctl,
427 .mmap = generic_file_mmap,
428 .open = ecryptfs_open,
429 .flush = ecryptfs_flush,
430 .release = ecryptfs_release,
431 .fsync = ecryptfs_fsync,
432 .fasync = ecryptfs_fasync,
433 .sendfile = ecryptfs_sendfile,
434};
435
436const struct file_operations ecryptfs_main_fops = {
437 .llseek = ecryptfs_llseek,
438 .read = do_sync_read,
439 .aio_read = ecryptfs_read_update_atime,
440 .write = do_sync_write,
441 .aio_write = generic_file_aio_write,
442 .readdir = ecryptfs_readdir,
443 .ioctl = ecryptfs_ioctl,
444 .mmap = generic_file_mmap,
445 .open = ecryptfs_open,
446 .flush = ecryptfs_flush,
447 .release = ecryptfs_release,
448 .fsync = ecryptfs_fsync,
449 .fasync = ecryptfs_fasync,
450 .sendfile = ecryptfs_sendfile,
451};
452
453static int
454ecryptfs_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
455 unsigned long arg)
456{
457 int rc = 0;
458 struct file *lower_file = NULL;
459
460 if (ecryptfs_file_to_private(file))
461 lower_file = ecryptfs_file_to_lower(file);
462 if (lower_file && lower_file->f_op && lower_file->f_op->ioctl)
463 rc = lower_file->f_op->ioctl(ecryptfs_inode_to_lower(inode),
464 lower_file, cmd, arg);
465 else
466 rc = -ENOTTY;
467 return rc;
468}