Revert "ecryptfs: forbid opening files without mmap handler"
[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>
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
AV
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
MH
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++;
addd65ad
MH
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 }
addd65ad
MH
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
addd65ad
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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;
7d6c7045
MH
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
e3ccaa97
TH
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;
bd243a4b 199 struct dentry *ecryptfs_dentry = file->f_path.dentry;
237fead6
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200 /* Private value of ecryptfs_dentry allocated in
201 * ecryptfs_lookup() */
237fead6 202 struct ecryptfs_file_info *file_info;
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203
204 /* Released in ecryptfs_release or end of function if failure */
c3762229 205 file_info = kmem_cache_zalloc(ecryptfs_file_info_cache, GFP_KERNEL);
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206 ecryptfs_set_file_private(file, file_info);
207 if (!file_info) {
208 ecryptfs_printk(KERN_ERR,
209 "Error attempting to allocate memory\n");
210 rc = -ENOMEM;
211 goto out;
212 }
237fead6 213 crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
237fead6 214 mutex_lock(&crypt_stat->cs_mutex);
e2bd99ec 215 if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)) {
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216 ecryptfs_printk(KERN_DEBUG, "Setting flags for stat...\n");
217 /* Policy code enabled in future release */
2ed92554
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218 crypt_stat->flags |= (ECRYPTFS_POLICY_APPLIED
219 | ECRYPTFS_ENCRYPTED);
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220 }
221 mutex_unlock(&crypt_stat->cs_mutex);
3b06b3eb 222 rc = ecryptfs_get_lower_file(ecryptfs_dentry, inode);
27992890
RS
223 if (rc) {
224 printk(KERN_ERR "%s: Error attempting to initialize "
332ab16f 225 "the lower file for the dentry with name "
27992890
RS
226 "[%s]; rc = [%d]\n", __func__,
227 ecryptfs_dentry->d_name.name, rc);
228 goto out_free;
72b55fff 229 }
0abe1169
RS
230 if ((ecryptfs_inode_to_private(inode)->lower_file->f_flags & O_ACCMODE)
231 == O_RDONLY && (file->f_flags & O_ACCMODE) != O_RDONLY) {
e27759d7 232 rc = -EPERM;
332ab16f 233 printk(KERN_WARNING "%s: Lower file is RO; eCryptfs "
e27759d7 234 "file must hence be opened RO\n", __func__);
332ab16f 235 goto out_put;
e27759d7 236 }
2ed92554
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237 ecryptfs_set_file_lower(
238 file, ecryptfs_inode_to_private(inode)->lower_file);
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239 if (S_ISDIR(ecryptfs_dentry->d_inode->i_mode)) {
240 ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
2f9b12a3 241 mutex_lock(&crypt_stat->cs_mutex);
e2bd99ec 242 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
2f9b12a3 243 mutex_unlock(&crypt_stat->cs_mutex);
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244 rc = 0;
245 goto out;
246 }
e3ccaa97
TH
247 rc = read_or_initialize_metadata(ecryptfs_dentry);
248 if (rc)
249 goto out_put;
888d57bb
JP
250 ecryptfs_printk(KERN_DEBUG, "inode w/ addr = [0x%p], i_ino = "
251 "[0x%.16lx] size: [0x%.16llx]\n", inode, inode->i_ino,
252 (unsigned long long)i_size_read(inode));
237fead6 253 goto out;
332ab16f
TH
254out_put:
255 ecryptfs_put_lower_file(inode);
2ed92554 256out_free:
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257 kmem_cache_free(ecryptfs_file_info_cache,
258 ecryptfs_file_to_private(file));
259out:
260 return rc;
261}
262
263static int ecryptfs_flush(struct file *file, fl_owner_t td)
264{
64e6651d
TH
265 struct file *lower_file = ecryptfs_file_to_lower(file);
266
267 if (lower_file->f_op && lower_file->f_op->flush) {
268 filemap_write_and_wait(file->f_mapping);
269 return lower_file->f_op->flush(lower_file, td);
270 }
271
272 return 0;
237fead6
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273}
274
275static int ecryptfs_release(struct inode *inode, struct file *file)
276{
332ab16f 277 ecryptfs_put_lower_file(inode);
2ed92554
MH
278 kmem_cache_free(ecryptfs_file_info_cache,
279 ecryptfs_file_to_private(file));
280 return 0;
237fead6
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281}
282
283static int
02c24a82 284ecryptfs_fsync(struct file *file, loff_t start, loff_t end, int datasync)
237fead6 285{
bc5abcf7
TH
286 int rc;
287
288 rc = filemap_write_and_wait(file->f_mapping);
289 if (rc)
290 return rc;
291
821f7494 292 return vfs_fsync(ecryptfs_file_to_lower(file), datasync);
237fead6
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293}
294
295static int ecryptfs_fasync(int fd, struct file *file, int flag)
296{
297 int rc = 0;
298 struct file *lower_file = NULL;
299
300 lower_file = ecryptfs_file_to_lower(file);
301 if (lower_file->f_op && lower_file->f_op->fasync)
302 rc = lower_file->f_op->fasync(fd, lower_file, flag);
303 return rc;
304}
305
c43f7b8f
TH
306static long
307ecryptfs_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
308{
309 struct file *lower_file = NULL;
310 long rc = -ENOTTY;
311
312 if (ecryptfs_file_to_private(file))
313 lower_file = ecryptfs_file_to_lower(file);
314 if (lower_file && lower_file->f_op && lower_file->f_op->unlocked_ioctl)
315 rc = lower_file->f_op->unlocked_ioctl(lower_file, cmd, arg);
316 return rc;
317}
318
319#ifdef CONFIG_COMPAT
320static long
321ecryptfs_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
322{
323 struct file *lower_file = NULL;
324 long rc = -ENOIOCTLCMD;
325
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->compat_ioctl)
329 rc = lower_file->f_op->compat_ioctl(lower_file, cmd, arg);
330 return rc;
331}
332#endif
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333
334const struct file_operations ecryptfs_dir_fops = {
335 .readdir = ecryptfs_readdir,
323ef68f 336 .read = generic_read_dir,
c43f7b8f
TH
337 .unlocked_ioctl = ecryptfs_unlocked_ioctl,
338#ifdef CONFIG_COMPAT
339 .compat_ioctl = ecryptfs_compat_ioctl,
340#endif
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341 .open = ecryptfs_open,
342 .flush = ecryptfs_flush,
343 .release = ecryptfs_release,
344 .fsync = ecryptfs_fsync,
345 .fasync = ecryptfs_fasync,
e9f6a99c 346 .splice_read = generic_file_splice_read,
6038f373 347 .llseek = default_llseek,
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348};
349
350const struct file_operations ecryptfs_main_fops = {
53a2731f 351 .llseek = generic_file_llseek,
237fead6
MH
352 .read = do_sync_read,
353 .aio_read = ecryptfs_read_update_atime,
354 .write = do_sync_write,
355 .aio_write = generic_file_aio_write,
356 .readdir = ecryptfs_readdir,
c43f7b8f
TH
357 .unlocked_ioctl = ecryptfs_unlocked_ioctl,
358#ifdef CONFIG_COMPAT
359 .compat_ioctl = ecryptfs_compat_ioctl,
360#endif
821f7494 361 .mmap = generic_file_mmap,
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362 .open = ecryptfs_open,
363 .flush = ecryptfs_flush,
364 .release = ecryptfs_release,
365 .fsync = ecryptfs_fsync,
366 .fasync = ecryptfs_fasync,
e9f6a99c 367 .splice_read = generic_file_splice_read,
237fead6 368};