2 * eCryptfs: Linux filesystem encryption layer
4 * Copyright (C) 1997-2004 Erez Zadok
5 * Copyright (C) 2001-2004 Stony Brook University
6 * Copyright (C) 2004-2007 International Business Machines Corp.
7 * Author(s): Michael A. Halcrow <mhalcrow@us.ibm.com>
8 * Michael C. Thompson <mcthomps@us.ibm.com>
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.
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.
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
26 #include <linux/file.h>
27 #include <linux/poll.h>
28 #include <linux/slab.h>
29 #include <linux/mount.h>
30 #include <linux/pagemap.h>
31 #include <linux/security.h>
32 #include <linux/compat.h>
33 #include <linux/fs_stack.h>
34 #include <linux/aio.h>
35 #include "ecryptfs_kernel.h"
38 * ecryptfs_read_update_atime
40 * generic_file_read updates the atime of upper layer inode. But, it
41 * doesn't give us a chance to update the atime of the lower layer
42 * inode. This function is a wrapper to generic_file_read. It
43 * updates the atime of the lower level inode if generic_file_read
44 * returns without any errors. This is to be used only for file reads.
45 * The function to be used for directory reads is ecryptfs_read.
47 static ssize_t
ecryptfs_read_update_atime(struct kiocb
*iocb
,
48 const struct iovec
*iov
,
49 unsigned long nr_segs
, loff_t pos
)
53 struct file
*file
= iocb
->ki_filp
;
55 rc
= generic_file_aio_read(iocb
, iov
, nr_segs
, pos
);
57 * Even though this is a async interface, we need to wait
58 * for IO to finish to update atime
60 if (-EIOCBQUEUED
== rc
)
61 rc
= wait_on_sync_kiocb(iocb
);
63 lower
.dentry
= ecryptfs_dentry_to_lower(file
->f_path
.dentry
);
64 lower
.mnt
= ecryptfs_dentry_to_lower_mnt(file
->f_path
.dentry
);
70 struct ecryptfs_getdents_callback
{
71 struct dir_context ctx
;
73 struct dentry
*dentry
;
79 /* Inspired by generic filldir in fs/readdir.c */
81 ecryptfs_filldir(void *dirent
, const char *lower_name
, int lower_namelen
,
82 loff_t offset
, u64 ino
, unsigned int d_type
)
84 struct ecryptfs_getdents_callback
*buf
=
85 (struct ecryptfs_getdents_callback
*)dirent
;
90 buf
->filldir_called
++;
91 rc
= ecryptfs_decode_and_decrypt_filename(&name
, &name_size
,
92 buf
->dentry
, lower_name
,
95 printk(KERN_ERR
"%s: Error attempting to decode and decrypt "
96 "filename [%s]; rc = [%d]\n", __func__
, lower_name
,
100 rc
= buf
->filldir(buf
->dirent
, name
, name_size
, offset
, ino
, d_type
);
103 buf
->entries_written
++;
110 * @file: The eCryptfs directory file
111 * @dirent: Directory entry handle
112 * @filldir: The filldir callback function
114 static int ecryptfs_readdir(struct file
*file
, void *dirent
, filldir_t filldir
)
117 struct file
*lower_file
;
119 struct ecryptfs_getdents_callback buf
;
121 lower_file
= ecryptfs_file_to_lower(file
);
122 lower_file
->f_pos
= file
->f_pos
;
123 inode
= file_inode(file
);
124 memset(&buf
, 0, sizeof(buf
));
126 buf
.dentry
= file
->f_path
.dentry
;
127 buf
.filldir
= filldir
;
128 buf
.filldir_called
= 0;
129 buf
.entries_written
= 0;
130 buf
.ctx
.actor
= ecryptfs_filldir
;
131 rc
= iterate_dir(lower_file
, &buf
.ctx
);
132 file
->f_pos
= lower_file
->f_pos
;
135 if (buf
.filldir_called
&& !buf
.entries_written
)
138 fsstack_copy_attr_atime(inode
,
139 file_inode(lower_file
));
144 struct kmem_cache
*ecryptfs_file_info_cache
;
146 static int read_or_initialize_metadata(struct dentry
*dentry
)
148 struct inode
*inode
= dentry
->d_inode
;
149 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
;
150 struct ecryptfs_crypt_stat
*crypt_stat
;
153 crypt_stat
= &ecryptfs_inode_to_private(inode
)->crypt_stat
;
154 mount_crypt_stat
= &ecryptfs_superblock_to_private(
155 inode
->i_sb
)->mount_crypt_stat
;
156 mutex_lock(&crypt_stat
->cs_mutex
);
158 if (crypt_stat
->flags
& ECRYPTFS_POLICY_APPLIED
&&
159 crypt_stat
->flags
& ECRYPTFS_KEY_VALID
) {
164 rc
= ecryptfs_read_metadata(dentry
);
168 if (mount_crypt_stat
->flags
& ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED
) {
169 crypt_stat
->flags
&= ~(ECRYPTFS_I_SIZE_INITIALIZED
170 | ECRYPTFS_ENCRYPTED
);
175 if (!(mount_crypt_stat
->flags
& ECRYPTFS_XATTR_METADATA_ENABLED
) &&
176 !i_size_read(ecryptfs_inode_to_lower(inode
))) {
177 rc
= ecryptfs_initialize_file(dentry
, inode
);
184 mutex_unlock(&crypt_stat
->cs_mutex
);
190 * @inode: inode speciying file to open
191 * @file: Structure to return filled in
193 * Opens the file specified by inode.
195 * Returns zero on success; non-zero otherwise
197 static int ecryptfs_open(struct inode
*inode
, struct file
*file
)
200 struct ecryptfs_crypt_stat
*crypt_stat
= NULL
;
201 struct ecryptfs_mount_crypt_stat
*mount_crypt_stat
;
202 struct dentry
*ecryptfs_dentry
= file
->f_path
.dentry
;
203 /* Private value of ecryptfs_dentry allocated in
204 * ecryptfs_lookup() */
205 struct ecryptfs_file_info
*file_info
;
207 mount_crypt_stat
= &ecryptfs_superblock_to_private(
208 ecryptfs_dentry
->d_sb
)->mount_crypt_stat
;
209 if ((mount_crypt_stat
->flags
& ECRYPTFS_ENCRYPTED_VIEW_ENABLED
)
210 && ((file
->f_flags
& O_WRONLY
) || (file
->f_flags
& O_RDWR
)
211 || (file
->f_flags
& O_CREAT
) || (file
->f_flags
& O_TRUNC
)
212 || (file
->f_flags
& O_APPEND
))) {
213 printk(KERN_WARNING
"Mount has encrypted view enabled; "
214 "files may only be read\n");
218 /* Released in ecryptfs_release or end of function if failure */
219 file_info
= kmem_cache_zalloc(ecryptfs_file_info_cache
, GFP_KERNEL
);
220 ecryptfs_set_file_private(file
, file_info
);
222 ecryptfs_printk(KERN_ERR
,
223 "Error attempting to allocate memory\n");
227 crypt_stat
= &ecryptfs_inode_to_private(inode
)->crypt_stat
;
228 mutex_lock(&crypt_stat
->cs_mutex
);
229 if (!(crypt_stat
->flags
& ECRYPTFS_POLICY_APPLIED
)) {
230 ecryptfs_printk(KERN_DEBUG
, "Setting flags for stat...\n");
231 /* Policy code enabled in future release */
232 crypt_stat
->flags
|= (ECRYPTFS_POLICY_APPLIED
233 | ECRYPTFS_ENCRYPTED
);
235 mutex_unlock(&crypt_stat
->cs_mutex
);
236 rc
= ecryptfs_get_lower_file(ecryptfs_dentry
, inode
);
238 printk(KERN_ERR
"%s: Error attempting to initialize "
239 "the lower file for the dentry with name "
240 "[%s]; rc = [%d]\n", __func__
,
241 ecryptfs_dentry
->d_name
.name
, rc
);
244 if ((ecryptfs_inode_to_private(inode
)->lower_file
->f_flags
& O_ACCMODE
)
245 == O_RDONLY
&& (file
->f_flags
& O_ACCMODE
) != O_RDONLY
) {
247 printk(KERN_WARNING
"%s: Lower file is RO; eCryptfs "
248 "file must hence be opened RO\n", __func__
);
251 ecryptfs_set_file_lower(
252 file
, ecryptfs_inode_to_private(inode
)->lower_file
);
253 if (S_ISDIR(ecryptfs_dentry
->d_inode
->i_mode
)) {
254 ecryptfs_printk(KERN_DEBUG
, "This is a directory\n");
255 mutex_lock(&crypt_stat
->cs_mutex
);
256 crypt_stat
->flags
&= ~(ECRYPTFS_ENCRYPTED
);
257 mutex_unlock(&crypt_stat
->cs_mutex
);
261 rc
= read_or_initialize_metadata(ecryptfs_dentry
);
264 ecryptfs_printk(KERN_DEBUG
, "inode w/ addr = [0x%p], i_ino = "
265 "[0x%.16lx] size: [0x%.16llx]\n", inode
, inode
->i_ino
,
266 (unsigned long long)i_size_read(inode
));
269 ecryptfs_put_lower_file(inode
);
271 kmem_cache_free(ecryptfs_file_info_cache
,
272 ecryptfs_file_to_private(file
));
277 static int ecryptfs_flush(struct file
*file
, fl_owner_t td
)
279 struct file
*lower_file
= ecryptfs_file_to_lower(file
);
281 if (lower_file
->f_op
&& lower_file
->f_op
->flush
) {
282 filemap_write_and_wait(file
->f_mapping
);
283 return lower_file
->f_op
->flush(lower_file
, td
);
289 static int ecryptfs_release(struct inode
*inode
, struct file
*file
)
291 ecryptfs_put_lower_file(inode
);
292 kmem_cache_free(ecryptfs_file_info_cache
,
293 ecryptfs_file_to_private(file
));
298 ecryptfs_fsync(struct file
*file
, loff_t start
, loff_t end
, int datasync
)
302 rc
= filemap_write_and_wait(file
->f_mapping
);
306 return vfs_fsync(ecryptfs_file_to_lower(file
), datasync
);
309 static int ecryptfs_fasync(int fd
, struct file
*file
, int flag
)
312 struct file
*lower_file
= NULL
;
314 lower_file
= ecryptfs_file_to_lower(file
);
315 if (lower_file
->f_op
&& lower_file
->f_op
->fasync
)
316 rc
= lower_file
->f_op
->fasync(fd
, lower_file
, flag
);
321 ecryptfs_unlocked_ioctl(struct file
*file
, unsigned int cmd
, unsigned long arg
)
323 struct file
*lower_file
= NULL
;
326 if (ecryptfs_file_to_private(file
))
327 lower_file
= ecryptfs_file_to_lower(file
);
328 if (lower_file
&& lower_file
->f_op
&& lower_file
->f_op
->unlocked_ioctl
)
329 rc
= lower_file
->f_op
->unlocked_ioctl(lower_file
, cmd
, arg
);
335 ecryptfs_compat_ioctl(struct file
*file
, unsigned int cmd
, unsigned long arg
)
337 struct file
*lower_file
= NULL
;
338 long rc
= -ENOIOCTLCMD
;
340 if (ecryptfs_file_to_private(file
))
341 lower_file
= ecryptfs_file_to_lower(file
);
342 if (lower_file
&& lower_file
->f_op
&& lower_file
->f_op
->compat_ioctl
)
343 rc
= lower_file
->f_op
->compat_ioctl(lower_file
, cmd
, arg
);
348 const struct file_operations ecryptfs_dir_fops
= {
349 .readdir
= ecryptfs_readdir
,
350 .read
= generic_read_dir
,
351 .unlocked_ioctl
= ecryptfs_unlocked_ioctl
,
353 .compat_ioctl
= ecryptfs_compat_ioctl
,
355 .open
= ecryptfs_open
,
356 .flush
= ecryptfs_flush
,
357 .release
= ecryptfs_release
,
358 .fsync
= ecryptfs_fsync
,
359 .fasync
= ecryptfs_fasync
,
360 .splice_read
= generic_file_splice_read
,
361 .llseek
= default_llseek
,
364 const struct file_operations ecryptfs_main_fops
= {
365 .llseek
= generic_file_llseek
,
366 .read
= do_sync_read
,
367 .aio_read
= ecryptfs_read_update_atime
,
368 .write
= do_sync_write
,
369 .aio_write
= generic_file_aio_write
,
370 .readdir
= ecryptfs_readdir
,
371 .unlocked_ioctl
= ecryptfs_unlocked_ioctl
,
373 .compat_ioctl
= ecryptfs_compat_ioctl
,
375 .mmap
= generic_file_mmap
,
376 .open
= ecryptfs_open
,
377 .flush
= ecryptfs_flush
,
378 .release
= ecryptfs_release
,
379 .fsync
= ecryptfs_fsync
,
380 .fasync
= ecryptfs_fasync
,
381 .splice_read
= generic_file_splice_read
,