eCryptfs: Write out all dirty pages just before releasing the lower file
[GitHub/mt8127/android_kernel_alcatel_ttab.git] / fs / ecryptfs / file.c
CommitLineData
237fead6
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1/**
2 * eCryptfs: Linux filesystem encryption layer
3 *
4 * Copyright (C) 1997-2004 Erez Zadok
5 * Copyright (C) 2001-2004 Stony Brook University
dd2a3b7a 6 * Copyright (C) 2004-2007 International Business Machines Corp.
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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>
5a0e3ad6 28#include <linux/slab.h>
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29#include <linux/mount.h>
30#include <linux/pagemap.h>
31#include <linux/security.h>
237fead6 32#include <linux/compat.h>
0cc72dc7 33#include <linux/fs_stack.h>
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34#include "ecryptfs_kernel.h"
35
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36/**
37 * ecryptfs_read_update_atime
38 *
39 * generic_file_read updates the atime of upper layer inode. But, it
40 * doesn't give us a chance to update the atime of the lower layer
41 * inode. This function is a wrapper to generic_file_read. It
42 * updates the atime of the lower level inode if generic_file_read
43 * returns without any errors. This is to be used only for file reads.
44 * The function to be used for directory reads is ecryptfs_read.
45 */
46static ssize_t ecryptfs_read_update_atime(struct kiocb *iocb,
47 const struct iovec *iov,
48 unsigned long nr_segs, loff_t pos)
49{
38a708d7 50 ssize_t rc;
68ac1234 51 struct path lower;
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52 struct file *file = iocb->ki_filp;
53
54 rc = generic_file_aio_read(iocb, iov, nr_segs, pos);
55 /*
56 * Even though this is a async interface, we need to wait
57 * for IO to finish to update atime
58 */
59 if (-EIOCBQUEUED == rc)
60 rc = wait_on_sync_kiocb(iocb);
61 if (rc >= 0) {
68ac1234
AV
62 lower.dentry = ecryptfs_dentry_to_lower(file->f_path.dentry);
63 lower.mnt = ecryptfs_dentry_to_lower_mnt(file->f_path.dentry);
64 touch_atime(&lower);
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65 }
66 return rc;
67}
68
69struct ecryptfs_getdents_callback {
70 void *dirent;
71 struct dentry *dentry;
72 filldir_t filldir;
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73 int filldir_called;
74 int entries_written;
75};
76
7d6c7045 77/* Inspired by generic filldir in fs/readdir.c */
237fead6 78static int
addd65ad
MH
79ecryptfs_filldir(void *dirent, const char *lower_name, int lower_namelen,
80 loff_t offset, u64 ino, unsigned int d_type)
237fead6 81{
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82 struct ecryptfs_getdents_callback *buf =
83 (struct ecryptfs_getdents_callback *)dirent;
a8f12864 84 size_t name_size;
addd65ad 85 char *name;
237fead6 86 int rc;
237fead6 87
237fead6 88 buf->filldir_called++;
addd65ad
MH
89 rc = ecryptfs_decode_and_decrypt_filename(&name, &name_size,
90 buf->dentry, lower_name,
91 lower_namelen);
92 if (rc) {
93 printk(KERN_ERR "%s: Error attempting to decode and decrypt "
94 "filename [%s]; rc = [%d]\n", __func__, lower_name,
95 rc);
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96 goto out;
97 }
addd65ad
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98 rc = buf->filldir(buf->dirent, name, name_size, offset, ino, d_type);
99 kfree(name);
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100 if (rc >= 0)
101 buf->entries_written++;
102out:
103 return rc;
104}
105
106/**
107 * ecryptfs_readdir
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108 * @file: The eCryptfs directory file
109 * @dirent: Directory entry handle
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110 * @filldir: The filldir callback function
111 */
112static int ecryptfs_readdir(struct file *file, void *dirent, filldir_t filldir)
113{
114 int rc;
115 struct file *lower_file;
116 struct inode *inode;
117 struct ecryptfs_getdents_callback buf;
118
119 lower_file = ecryptfs_file_to_lower(file);
120 lower_file->f_pos = file->f_pos;
bd243a4b 121 inode = file->f_path.dentry->d_inode;
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122 memset(&buf, 0, sizeof(buf));
123 buf.dirent = dirent;
bd243a4b 124 buf.dentry = file->f_path.dentry;
237fead6 125 buf.filldir = filldir;
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126 buf.filldir_called = 0;
127 buf.entries_written = 0;
237fead6 128 rc = vfs_readdir(lower_file, ecryptfs_filldir, (void *)&buf);
237fead6 129 file->f_pos = lower_file->f_pos;
7d6c7045
MH
130 if (rc < 0)
131 goto out;
132 if (buf.filldir_called && !buf.entries_written)
133 goto out;
237fead6 134 if (rc >= 0)
7d6c7045
MH
135 fsstack_copy_attr_atime(inode,
136 lower_file->f_path.dentry->d_inode);
137out:
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138 return rc;
139}
140
141struct kmem_cache *ecryptfs_file_info_cache;
142
e3ccaa97
TH
143static int read_or_initialize_metadata(struct dentry *dentry)
144{
145 struct inode *inode = dentry->d_inode;
146 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
147 struct ecryptfs_crypt_stat *crypt_stat;
148 int rc;
149
150 crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
151 mount_crypt_stat = &ecryptfs_superblock_to_private(
152 inode->i_sb)->mount_crypt_stat;
153 mutex_lock(&crypt_stat->cs_mutex);
154
155 if (crypt_stat->flags & ECRYPTFS_POLICY_APPLIED &&
156 crypt_stat->flags & ECRYPTFS_KEY_VALID) {
157 rc = 0;
158 goto out;
159 }
160
161 rc = ecryptfs_read_metadata(dentry);
162 if (!rc)
163 goto out;
164
165 if (mount_crypt_stat->flags & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED) {
166 crypt_stat->flags &= ~(ECRYPTFS_I_SIZE_INITIALIZED
167 | ECRYPTFS_ENCRYPTED);
168 rc = 0;
169 goto out;
170 }
171
172 if (!(mount_crypt_stat->flags & ECRYPTFS_XATTR_METADATA_ENABLED) &&
173 !i_size_read(ecryptfs_inode_to_lower(inode))) {
174 rc = ecryptfs_initialize_file(dentry, inode);
175 if (!rc)
176 goto out;
177 }
178
179 rc = -EIO;
180out:
181 mutex_unlock(&crypt_stat->cs_mutex);
182 return rc;
183}
184
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185/**
186 * ecryptfs_open
187 * @inode: inode speciying file to open
188 * @file: Structure to return filled in
189 *
190 * Opens the file specified by inode.
191 *
192 * Returns zero on success; non-zero otherwise
193 */
194static int ecryptfs_open(struct inode *inode, struct file *file)
195{
196 int rc = 0;
197 struct ecryptfs_crypt_stat *crypt_stat = NULL;
198 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
bd243a4b 199 struct dentry *ecryptfs_dentry = file->f_path.dentry;
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200 /* Private value of ecryptfs_dentry allocated in
201 * ecryptfs_lookup() */
4aa25bcb 202 struct dentry *lower_dentry;
237fead6 203 struct ecryptfs_file_info *file_info;
237fead6 204
e77a56dd
MH
205 mount_crypt_stat = &ecryptfs_superblock_to_private(
206 ecryptfs_dentry->d_sb)->mount_crypt_stat;
207 if ((mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
208 && ((file->f_flags & O_WRONLY) || (file->f_flags & O_RDWR)
209 || (file->f_flags & O_CREAT) || (file->f_flags & O_TRUNC)
210 || (file->f_flags & O_APPEND))) {
211 printk(KERN_WARNING "Mount has encrypted view enabled; "
212 "files may only be read\n");
213 rc = -EPERM;
214 goto out;
215 }
237fead6 216 /* Released in ecryptfs_release or end of function if failure */
c3762229 217 file_info = kmem_cache_zalloc(ecryptfs_file_info_cache, GFP_KERNEL);
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218 ecryptfs_set_file_private(file, file_info);
219 if (!file_info) {
220 ecryptfs_printk(KERN_ERR,
221 "Error attempting to allocate memory\n");
222 rc = -ENOMEM;
223 goto out;
224 }
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225 lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
226 crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
237fead6 227 mutex_lock(&crypt_stat->cs_mutex);
e2bd99ec 228 if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)) {
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229 ecryptfs_printk(KERN_DEBUG, "Setting flags for stat...\n");
230 /* Policy code enabled in future release */
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231 crypt_stat->flags |= (ECRYPTFS_POLICY_APPLIED
232 | ECRYPTFS_ENCRYPTED);
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233 }
234 mutex_unlock(&crypt_stat->cs_mutex);
3b06b3eb 235 rc = ecryptfs_get_lower_file(ecryptfs_dentry, inode);
27992890
RS
236 if (rc) {
237 printk(KERN_ERR "%s: Error attempting to initialize "
332ab16f 238 "the lower file for the dentry with name "
27992890
RS
239 "[%s]; rc = [%d]\n", __func__,
240 ecryptfs_dentry->d_name.name, rc);
241 goto out_free;
72b55fff 242 }
0abe1169
RS
243 if ((ecryptfs_inode_to_private(inode)->lower_file->f_flags & O_ACCMODE)
244 == O_RDONLY && (file->f_flags & O_ACCMODE) != O_RDONLY) {
e27759d7 245 rc = -EPERM;
332ab16f 246 printk(KERN_WARNING "%s: Lower file is RO; eCryptfs "
e27759d7 247 "file must hence be opened RO\n", __func__);
332ab16f 248 goto out_put;
e27759d7 249 }
2ed92554
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250 ecryptfs_set_file_lower(
251 file, ecryptfs_inode_to_private(inode)->lower_file);
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252 if (S_ISDIR(ecryptfs_dentry->d_inode->i_mode)) {
253 ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
2f9b12a3 254 mutex_lock(&crypt_stat->cs_mutex);
e2bd99ec 255 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
2f9b12a3 256 mutex_unlock(&crypt_stat->cs_mutex);
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257 rc = 0;
258 goto out;
259 }
e3ccaa97
TH
260 rc = read_or_initialize_metadata(ecryptfs_dentry);
261 if (rc)
262 goto out_put;
888d57bb
JP
263 ecryptfs_printk(KERN_DEBUG, "inode w/ addr = [0x%p], i_ino = "
264 "[0x%.16lx] size: [0x%.16llx]\n", inode, inode->i_ino,
265 (unsigned long long)i_size_read(inode));
237fead6 266 goto out;
332ab16f
TH
267out_put:
268 ecryptfs_put_lower_file(inode);
2ed92554 269out_free:
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270 kmem_cache_free(ecryptfs_file_info_cache,
271 ecryptfs_file_to_private(file));
272out:
273 return rc;
274}
275
276static int ecryptfs_flush(struct file *file, fl_owner_t td)
277{
332ab16f
TH
278 return file->f_mode & FMODE_WRITE
279 ? filemap_write_and_wait(file->f_mapping) : 0;
237fead6
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280}
281
282static int ecryptfs_release(struct inode *inode, struct file *file)
283{
332ab16f 284 ecryptfs_put_lower_file(inode);
2ed92554
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285 kmem_cache_free(ecryptfs_file_info_cache,
286 ecryptfs_file_to_private(file));
287 return 0;
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288}
289
290static int
02c24a82 291ecryptfs_fsync(struct file *file, loff_t start, loff_t end, int datasync)
237fead6 292{
821f7494 293 return vfs_fsync(ecryptfs_file_to_lower(file), datasync);
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294}
295
296static int ecryptfs_fasync(int fd, struct file *file, int flag)
297{
298 int rc = 0;
299 struct file *lower_file = NULL;
300
301 lower_file = ecryptfs_file_to_lower(file);
302 if (lower_file->f_op && lower_file->f_op->fasync)
303 rc = lower_file->f_op->fasync(fd, lower_file, flag);
304 return rc;
305}
306
c43f7b8f
TH
307static long
308ecryptfs_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
309{
310 struct file *lower_file = NULL;
311 long rc = -ENOTTY;
312
313 if (ecryptfs_file_to_private(file))
314 lower_file = ecryptfs_file_to_lower(file);
315 if (lower_file && lower_file->f_op && lower_file->f_op->unlocked_ioctl)
316 rc = lower_file->f_op->unlocked_ioctl(lower_file, cmd, arg);
317 return rc;
318}
319
320#ifdef CONFIG_COMPAT
321static long
322ecryptfs_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
323{
324 struct file *lower_file = NULL;
325 long rc = -ENOIOCTLCMD;
326
327 if (ecryptfs_file_to_private(file))
328 lower_file = ecryptfs_file_to_lower(file);
329 if (lower_file && lower_file->f_op && lower_file->f_op->compat_ioctl)
330 rc = lower_file->f_op->compat_ioctl(lower_file, cmd, arg);
331 return rc;
332}
333#endif
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334
335const struct file_operations ecryptfs_dir_fops = {
336 .readdir = ecryptfs_readdir,
323ef68f 337 .read = generic_read_dir,
c43f7b8f
TH
338 .unlocked_ioctl = ecryptfs_unlocked_ioctl,
339#ifdef CONFIG_COMPAT
340 .compat_ioctl = ecryptfs_compat_ioctl,
341#endif
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342 .open = ecryptfs_open,
343 .flush = ecryptfs_flush,
344 .release = ecryptfs_release,
345 .fsync = ecryptfs_fsync,
346 .fasync = ecryptfs_fasync,
e9f6a99c 347 .splice_read = generic_file_splice_read,
6038f373 348 .llseek = default_llseek,
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349};
350
351const struct file_operations ecryptfs_main_fops = {
53a2731f 352 .llseek = generic_file_llseek,
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353 .read = do_sync_read,
354 .aio_read = ecryptfs_read_update_atime,
355 .write = do_sync_write,
356 .aio_write = generic_file_aio_write,
357 .readdir = ecryptfs_readdir,
c43f7b8f
TH
358 .unlocked_ioctl = ecryptfs_unlocked_ioctl,
359#ifdef CONFIG_COMPAT
360 .compat_ioctl = ecryptfs_compat_ioctl,
361#endif
821f7494 362 .mmap = generic_file_mmap,
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363 .open = ecryptfs_open,
364 .flush = ecryptfs_flush,
365 .release = ecryptfs_release,
366 .fsync = ecryptfs_fsync,
367 .fasync = ecryptfs_fasync,
e9f6a99c 368 .splice_read = generic_file_splice_read,
237fead6 369};