Update eCryptFS maintainers
[GitHub/mt8127/android_kernel_alcatel_ttab.git] / fs / ecryptfs / file.c
CommitLineData
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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>
a27bb332 34#include <linux/aio.h>
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35#include "ecryptfs_kernel.h"
36
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37/**
38 * ecryptfs_read_update_atime
39 *
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.
46 */
47static ssize_t ecryptfs_read_update_atime(struct kiocb *iocb,
48 const struct iovec *iov,
49 unsigned long nr_segs, loff_t pos)
50{
38a708d7 51 ssize_t rc;
68ac1234 52 struct path lower;
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53 struct file *file = iocb->ki_filp;
54
55 rc = generic_file_aio_read(iocb, iov, nr_segs, pos);
56 /*
57 * Even though this is a async interface, we need to wait
58 * for IO to finish to update atime
59 */
60 if (-EIOCBQUEUED == rc)
61 rc = wait_on_sync_kiocb(iocb);
62 if (rc >= 0) {
68ac1234
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63 lower.dentry = ecryptfs_dentry_to_lower(file->f_path.dentry);
64 lower.mnt = ecryptfs_dentry_to_lower_mnt(file->f_path.dentry);
65 touch_atime(&lower);
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66 }
67 return rc;
68}
69
70struct ecryptfs_getdents_callback {
71 void *dirent;
72 struct dentry *dentry;
73 filldir_t filldir;
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74 int filldir_called;
75 int entries_written;
76};
77
7d6c7045 78/* Inspired by generic filldir in fs/readdir.c */
237fead6 79static int
addd65ad
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80ecryptfs_filldir(void *dirent, const char *lower_name, int lower_namelen,
81 loff_t offset, u64 ino, unsigned int d_type)
237fead6 82{
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83 struct ecryptfs_getdents_callback *buf =
84 (struct ecryptfs_getdents_callback *)dirent;
a8f12864 85 size_t name_size;
addd65ad 86 char *name;
237fead6 87 int rc;
237fead6 88
237fead6 89 buf->filldir_called++;
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90 rc = ecryptfs_decode_and_decrypt_filename(&name, &name_size,
91 buf->dentry, lower_name,
92 lower_namelen);
93 if (rc) {
94 printk(KERN_ERR "%s: Error attempting to decode and decrypt "
95 "filename [%s]; rc = [%d]\n", __func__, lower_name,
96 rc);
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97 goto out;
98 }
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99 rc = buf->filldir(buf->dirent, name, name_size, offset, ino, d_type);
100 kfree(name);
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101 if (rc >= 0)
102 buf->entries_written++;
103out:
104 return rc;
105}
106
107/**
108 * ecryptfs_readdir
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109 * @file: The eCryptfs directory file
110 * @dirent: Directory entry handle
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111 * @filldir: The filldir callback function
112 */
113static int ecryptfs_readdir(struct file *file, void *dirent, filldir_t filldir)
114{
115 int rc;
116 struct file *lower_file;
117 struct inode *inode;
118 struct ecryptfs_getdents_callback buf;
119
120 lower_file = ecryptfs_file_to_lower(file);
121 lower_file->f_pos = file->f_pos;
496ad9aa 122 inode = file_inode(file);
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123 memset(&buf, 0, sizeof(buf));
124 buf.dirent = dirent;
bd243a4b 125 buf.dentry = file->f_path.dentry;
237fead6 126 buf.filldir = filldir;
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127 buf.filldir_called = 0;
128 buf.entries_written = 0;
237fead6 129 rc = vfs_readdir(lower_file, ecryptfs_filldir, (void *)&buf);
237fead6 130 file->f_pos = lower_file->f_pos;
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131 if (rc < 0)
132 goto out;
133 if (buf.filldir_called && !buf.entries_written)
134 goto out;
237fead6 135 if (rc >= 0)
7d6c7045 136 fsstack_copy_attr_atime(inode,
496ad9aa 137 file_inode(lower_file));
7d6c7045 138out:
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139 return rc;
140}
141
142struct kmem_cache *ecryptfs_file_info_cache;
143
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144static int read_or_initialize_metadata(struct dentry *dentry)
145{
146 struct inode *inode = dentry->d_inode;
147 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
148 struct ecryptfs_crypt_stat *crypt_stat;
149 int rc;
150
151 crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
152 mount_crypt_stat = &ecryptfs_superblock_to_private(
153 inode->i_sb)->mount_crypt_stat;
154 mutex_lock(&crypt_stat->cs_mutex);
155
156 if (crypt_stat->flags & ECRYPTFS_POLICY_APPLIED &&
157 crypt_stat->flags & ECRYPTFS_KEY_VALID) {
158 rc = 0;
159 goto out;
160 }
161
162 rc = ecryptfs_read_metadata(dentry);
163 if (!rc)
164 goto out;
165
166 if (mount_crypt_stat->flags & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED) {
167 crypt_stat->flags &= ~(ECRYPTFS_I_SIZE_INITIALIZED
168 | ECRYPTFS_ENCRYPTED);
169 rc = 0;
170 goto out;
171 }
172
173 if (!(mount_crypt_stat->flags & ECRYPTFS_XATTR_METADATA_ENABLED) &&
174 !i_size_read(ecryptfs_inode_to_lower(inode))) {
175 rc = ecryptfs_initialize_file(dentry, inode);
176 if (!rc)
177 goto out;
178 }
179
180 rc = -EIO;
181out:
182 mutex_unlock(&crypt_stat->cs_mutex);
183 return rc;
184}
185
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186/**
187 * ecryptfs_open
188 * @inode: inode speciying file to open
189 * @file: Structure to return filled in
190 *
191 * Opens the file specified by inode.
192 *
193 * Returns zero on success; non-zero otherwise
194 */
195static int ecryptfs_open(struct inode *inode, struct file *file)
196{
197 int rc = 0;
198 struct ecryptfs_crypt_stat *crypt_stat = NULL;
199 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
bd243a4b 200 struct dentry *ecryptfs_dentry = file->f_path.dentry;
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201 /* Private value of ecryptfs_dentry allocated in
202 * ecryptfs_lookup() */
237fead6 203 struct ecryptfs_file_info *file_info;
237fead6 204
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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 }
237fead6 225 crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
237fead6 226 mutex_lock(&crypt_stat->cs_mutex);
e2bd99ec 227 if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)) {
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228 ecryptfs_printk(KERN_DEBUG, "Setting flags for stat...\n");
229 /* Policy code enabled in future release */
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230 crypt_stat->flags |= (ECRYPTFS_POLICY_APPLIED
231 | ECRYPTFS_ENCRYPTED);
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232 }
233 mutex_unlock(&crypt_stat->cs_mutex);
3b06b3eb 234 rc = ecryptfs_get_lower_file(ecryptfs_dentry, inode);
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235 if (rc) {
236 printk(KERN_ERR "%s: Error attempting to initialize "
332ab16f 237 "the lower file for the dentry with name "
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238 "[%s]; rc = [%d]\n", __func__,
239 ecryptfs_dentry->d_name.name, rc);
240 goto out_free;
72b55fff 241 }
0abe1169
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242 if ((ecryptfs_inode_to_private(inode)->lower_file->f_flags & O_ACCMODE)
243 == O_RDONLY && (file->f_flags & O_ACCMODE) != O_RDONLY) {
e27759d7 244 rc = -EPERM;
332ab16f 245 printk(KERN_WARNING "%s: Lower file is RO; eCryptfs "
e27759d7 246 "file must hence be opened RO\n", __func__);
332ab16f 247 goto out_put;
e27759d7 248 }
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249 ecryptfs_set_file_lower(
250 file, ecryptfs_inode_to_private(inode)->lower_file);
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251 if (S_ISDIR(ecryptfs_dentry->d_inode->i_mode)) {
252 ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
2f9b12a3 253 mutex_lock(&crypt_stat->cs_mutex);
e2bd99ec 254 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
2f9b12a3 255 mutex_unlock(&crypt_stat->cs_mutex);
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256 rc = 0;
257 goto out;
258 }
e3ccaa97
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259 rc = read_or_initialize_metadata(ecryptfs_dentry);
260 if (rc)
261 goto out_put;
888d57bb
JP
262 ecryptfs_printk(KERN_DEBUG, "inode w/ addr = [0x%p], i_ino = "
263 "[0x%.16lx] size: [0x%.16llx]\n", inode, inode->i_ino,
264 (unsigned long long)i_size_read(inode));
237fead6 265 goto out;
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266out_put:
267 ecryptfs_put_lower_file(inode);
2ed92554 268out_free:
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269 kmem_cache_free(ecryptfs_file_info_cache,
270 ecryptfs_file_to_private(file));
271out:
272 return rc;
273}
274
275static int ecryptfs_flush(struct file *file, fl_owner_t td)
276{
64e6651d
TH
277 struct file *lower_file = ecryptfs_file_to_lower(file);
278
279 if (lower_file->f_op && lower_file->f_op->flush) {
280 filemap_write_and_wait(file->f_mapping);
281 return lower_file->f_op->flush(lower_file, td);
282 }
283
284 return 0;
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285}
286
287static int ecryptfs_release(struct inode *inode, struct file *file)
288{
332ab16f 289 ecryptfs_put_lower_file(inode);
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290 kmem_cache_free(ecryptfs_file_info_cache,
291 ecryptfs_file_to_private(file));
292 return 0;
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293}
294
295static int
02c24a82 296ecryptfs_fsync(struct file *file, loff_t start, loff_t end, int datasync)
237fead6 297{
c15cddd9 298 filemap_write_and_wait(file->f_mapping);
821f7494 299 return vfs_fsync(ecryptfs_file_to_lower(file), datasync);
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300}
301
302static int ecryptfs_fasync(int fd, struct file *file, int flag)
303{
304 int rc = 0;
305 struct file *lower_file = NULL;
306
307 lower_file = ecryptfs_file_to_lower(file);
308 if (lower_file->f_op && lower_file->f_op->fasync)
309 rc = lower_file->f_op->fasync(fd, lower_file, flag);
310 return rc;
311}
312
c43f7b8f
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313static long
314ecryptfs_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
315{
316 struct file *lower_file = NULL;
317 long rc = -ENOTTY;
318
319 if (ecryptfs_file_to_private(file))
320 lower_file = ecryptfs_file_to_lower(file);
321 if (lower_file && lower_file->f_op && lower_file->f_op->unlocked_ioctl)
322 rc = lower_file->f_op->unlocked_ioctl(lower_file, cmd, arg);
323 return rc;
324}
325
326#ifdef CONFIG_COMPAT
327static long
328ecryptfs_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
329{
330 struct file *lower_file = NULL;
331 long rc = -ENOIOCTLCMD;
332
333 if (ecryptfs_file_to_private(file))
334 lower_file = ecryptfs_file_to_lower(file);
335 if (lower_file && lower_file->f_op && lower_file->f_op->compat_ioctl)
336 rc = lower_file->f_op->compat_ioctl(lower_file, cmd, arg);
337 return rc;
338}
339#endif
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340
341const struct file_operations ecryptfs_dir_fops = {
342 .readdir = ecryptfs_readdir,
323ef68f 343 .read = generic_read_dir,
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344 .unlocked_ioctl = ecryptfs_unlocked_ioctl,
345#ifdef CONFIG_COMPAT
346 .compat_ioctl = ecryptfs_compat_ioctl,
347#endif
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348 .open = ecryptfs_open,
349 .flush = ecryptfs_flush,
350 .release = ecryptfs_release,
351 .fsync = ecryptfs_fsync,
352 .fasync = ecryptfs_fasync,
e9f6a99c 353 .splice_read = generic_file_splice_read,
6038f373 354 .llseek = default_llseek,
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355};
356
357const struct file_operations ecryptfs_main_fops = {
53a2731f 358 .llseek = generic_file_llseek,
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359 .read = do_sync_read,
360 .aio_read = ecryptfs_read_update_atime,
361 .write = do_sync_write,
362 .aio_write = generic_file_aio_write,
363 .readdir = ecryptfs_readdir,
c43f7b8f
TH
364 .unlocked_ioctl = ecryptfs_unlocked_ioctl,
365#ifdef CONFIG_COMPAT
366 .compat_ioctl = ecryptfs_compat_ioctl,
367#endif
821f7494 368 .mmap = generic_file_mmap,
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369 .open = ecryptfs_open,
370 .flush = ecryptfs_flush,
371 .release = ecryptfs_release,
372 .fsync = ecryptfs_fsync,
373 .fasync = ecryptfs_fasync,
e9f6a99c 374 .splice_read = generic_file_splice_read,
237fead6 375};