eCryptfs: Initialize empty lower files when opening them
[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
237fead6
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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;
237fead6
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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
addd65ad
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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
32001d6f
TH
141static void ecryptfs_vma_close(struct vm_area_struct *vma)
142{
143 filemap_write_and_wait(vma->vm_file->f_mapping);
144}
145
146static const struct vm_operations_struct ecryptfs_file_vm_ops = {
147 .close = ecryptfs_vma_close,
148 .fault = filemap_fault,
149};
150
151static int ecryptfs_file_mmap(struct file *file, struct vm_area_struct *vma)
152{
153 int rc;
154
155 rc = generic_file_mmap(file, vma);
156 if (!rc)
157 vma->vm_ops = &ecryptfs_file_vm_ops;
158
159 return rc;
160}
161
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162struct kmem_cache *ecryptfs_file_info_cache;
163
e3ccaa97
TH
164static int read_or_initialize_metadata(struct dentry *dentry)
165{
166 struct inode *inode = dentry->d_inode;
167 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
168 struct ecryptfs_crypt_stat *crypt_stat;
169 int rc;
170
171 crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
172 mount_crypt_stat = &ecryptfs_superblock_to_private(
173 inode->i_sb)->mount_crypt_stat;
174 mutex_lock(&crypt_stat->cs_mutex);
175
176 if (crypt_stat->flags & ECRYPTFS_POLICY_APPLIED &&
177 crypt_stat->flags & ECRYPTFS_KEY_VALID) {
178 rc = 0;
179 goto out;
180 }
181
182 rc = ecryptfs_read_metadata(dentry);
183 if (!rc)
184 goto out;
185
186 if (mount_crypt_stat->flags & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED) {
187 crypt_stat->flags &= ~(ECRYPTFS_I_SIZE_INITIALIZED
188 | ECRYPTFS_ENCRYPTED);
189 rc = 0;
190 goto out;
191 }
192
193 if (!(mount_crypt_stat->flags & ECRYPTFS_XATTR_METADATA_ENABLED) &&
194 !i_size_read(ecryptfs_inode_to_lower(inode))) {
195 rc = ecryptfs_initialize_file(dentry, inode);
196 if (!rc)
197 goto out;
198 }
199
200 rc = -EIO;
201out:
202 mutex_unlock(&crypt_stat->cs_mutex);
203 return rc;
204}
205
237fead6
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206/**
207 * ecryptfs_open
208 * @inode: inode speciying file to open
209 * @file: Structure to return filled in
210 *
211 * Opens the file specified by inode.
212 *
213 * Returns zero on success; non-zero otherwise
214 */
215static int ecryptfs_open(struct inode *inode, struct file *file)
216{
217 int rc = 0;
218 struct ecryptfs_crypt_stat *crypt_stat = NULL;
219 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
bd243a4b 220 struct dentry *ecryptfs_dentry = file->f_path.dentry;
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MH
221 /* Private value of ecryptfs_dentry allocated in
222 * ecryptfs_lookup() */
4aa25bcb 223 struct dentry *lower_dentry;
237fead6 224 struct ecryptfs_file_info *file_info;
237fead6 225
e77a56dd
MH
226 mount_crypt_stat = &ecryptfs_superblock_to_private(
227 ecryptfs_dentry->d_sb)->mount_crypt_stat;
228 if ((mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
229 && ((file->f_flags & O_WRONLY) || (file->f_flags & O_RDWR)
230 || (file->f_flags & O_CREAT) || (file->f_flags & O_TRUNC)
231 || (file->f_flags & O_APPEND))) {
232 printk(KERN_WARNING "Mount has encrypted view enabled; "
233 "files may only be read\n");
234 rc = -EPERM;
235 goto out;
236 }
237fead6 237 /* Released in ecryptfs_release or end of function if failure */
c3762229 238 file_info = kmem_cache_zalloc(ecryptfs_file_info_cache, GFP_KERNEL);
237fead6
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239 ecryptfs_set_file_private(file, file_info);
240 if (!file_info) {
241 ecryptfs_printk(KERN_ERR,
242 "Error attempting to allocate memory\n");
243 rc = -ENOMEM;
244 goto out;
245 }
237fead6
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246 lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
247 crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
237fead6 248 mutex_lock(&crypt_stat->cs_mutex);
e2bd99ec 249 if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)) {
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250 ecryptfs_printk(KERN_DEBUG, "Setting flags for stat...\n");
251 /* Policy code enabled in future release */
2ed92554
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252 crypt_stat->flags |= (ECRYPTFS_POLICY_APPLIED
253 | ECRYPTFS_ENCRYPTED);
237fead6
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254 }
255 mutex_unlock(&crypt_stat->cs_mutex);
3b06b3eb 256 rc = ecryptfs_get_lower_file(ecryptfs_dentry, inode);
27992890
RS
257 if (rc) {
258 printk(KERN_ERR "%s: Error attempting to initialize "
332ab16f 259 "the lower file for the dentry with name "
27992890
RS
260 "[%s]; rc = [%d]\n", __func__,
261 ecryptfs_dentry->d_name.name, rc);
262 goto out_free;
72b55fff 263 }
0abe1169
RS
264 if ((ecryptfs_inode_to_private(inode)->lower_file->f_flags & O_ACCMODE)
265 == O_RDONLY && (file->f_flags & O_ACCMODE) != O_RDONLY) {
e27759d7 266 rc = -EPERM;
332ab16f 267 printk(KERN_WARNING "%s: Lower file is RO; eCryptfs "
e27759d7 268 "file must hence be opened RO\n", __func__);
332ab16f 269 goto out_put;
e27759d7 270 }
2ed92554
MH
271 ecryptfs_set_file_lower(
272 file, ecryptfs_inode_to_private(inode)->lower_file);
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273 if (S_ISDIR(ecryptfs_dentry->d_inode->i_mode)) {
274 ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
2f9b12a3 275 mutex_lock(&crypt_stat->cs_mutex);
e2bd99ec 276 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
2f9b12a3 277 mutex_unlock(&crypt_stat->cs_mutex);
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278 rc = 0;
279 goto out;
280 }
e3ccaa97
TH
281 rc = read_or_initialize_metadata(ecryptfs_dentry);
282 if (rc)
283 goto out_put;
888d57bb
JP
284 ecryptfs_printk(KERN_DEBUG, "inode w/ addr = [0x%p], i_ino = "
285 "[0x%.16lx] size: [0x%.16llx]\n", inode, inode->i_ino,
286 (unsigned long long)i_size_read(inode));
237fead6 287 goto out;
332ab16f
TH
288out_put:
289 ecryptfs_put_lower_file(inode);
2ed92554 290out_free:
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291 kmem_cache_free(ecryptfs_file_info_cache,
292 ecryptfs_file_to_private(file));
293out:
294 return rc;
295}
296
297static int ecryptfs_flush(struct file *file, fl_owner_t td)
298{
332ab16f
TH
299 return file->f_mode & FMODE_WRITE
300 ? filemap_write_and_wait(file->f_mapping) : 0;
237fead6
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301}
302
303static int ecryptfs_release(struct inode *inode, struct file *file)
304{
332ab16f 305 ecryptfs_put_lower_file(inode);
2ed92554
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306 kmem_cache_free(ecryptfs_file_info_cache,
307 ecryptfs_file_to_private(file));
308 return 0;
237fead6
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309}
310
311static int
02c24a82 312ecryptfs_fsync(struct file *file, loff_t start, loff_t end, int datasync)
237fead6 313{
57db4e8d
TL
314 int rc = 0;
315
02c24a82 316 rc = generic_file_fsync(file, start, end, datasync);
57db4e8d
TL
317 if (rc)
318 goto out;
02c24a82
JB
319 rc = vfs_fsync_range(ecryptfs_file_to_lower(file), start, end,
320 datasync);
57db4e8d
TL
321out:
322 return rc;
237fead6
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323}
324
325static int ecryptfs_fasync(int fd, struct file *file, int flag)
326{
327 int rc = 0;
328 struct file *lower_file = NULL;
329
330 lower_file = ecryptfs_file_to_lower(file);
331 if (lower_file->f_op && lower_file->f_op->fasync)
332 rc = lower_file->f_op->fasync(fd, lower_file, flag);
333 return rc;
334}
335
c43f7b8f
TH
336static long
337ecryptfs_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
338{
339 struct file *lower_file = NULL;
340 long rc = -ENOTTY;
341
342 if (ecryptfs_file_to_private(file))
343 lower_file = ecryptfs_file_to_lower(file);
344 if (lower_file && lower_file->f_op && lower_file->f_op->unlocked_ioctl)
345 rc = lower_file->f_op->unlocked_ioctl(lower_file, cmd, arg);
346 return rc;
347}
348
349#ifdef CONFIG_COMPAT
350static long
351ecryptfs_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
352{
353 struct file *lower_file = NULL;
354 long rc = -ENOIOCTLCMD;
355
356 if (ecryptfs_file_to_private(file))
357 lower_file = ecryptfs_file_to_lower(file);
358 if (lower_file && lower_file->f_op && lower_file->f_op->compat_ioctl)
359 rc = lower_file->f_op->compat_ioctl(lower_file, cmd, arg);
360 return rc;
361}
362#endif
237fead6
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363
364const struct file_operations ecryptfs_dir_fops = {
365 .readdir = ecryptfs_readdir,
323ef68f 366 .read = generic_read_dir,
c43f7b8f
TH
367 .unlocked_ioctl = ecryptfs_unlocked_ioctl,
368#ifdef CONFIG_COMPAT
369 .compat_ioctl = ecryptfs_compat_ioctl,
370#endif
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371 .open = ecryptfs_open,
372 .flush = ecryptfs_flush,
373 .release = ecryptfs_release,
374 .fsync = ecryptfs_fsync,
375 .fasync = ecryptfs_fasync,
e9f6a99c 376 .splice_read = generic_file_splice_read,
6038f373 377 .llseek = default_llseek,
237fead6
MH
378};
379
380const struct file_operations ecryptfs_main_fops = {
53a2731f 381 .llseek = generic_file_llseek,
237fead6
MH
382 .read = do_sync_read,
383 .aio_read = ecryptfs_read_update_atime,
384 .write = do_sync_write,
385 .aio_write = generic_file_aio_write,
386 .readdir = ecryptfs_readdir,
c43f7b8f
TH
387 .unlocked_ioctl = ecryptfs_unlocked_ioctl,
388#ifdef CONFIG_COMPAT
389 .compat_ioctl = ecryptfs_compat_ioctl,
390#endif
32001d6f 391 .mmap = ecryptfs_file_mmap,
237fead6
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392 .open = ecryptfs_open,
393 .flush = ecryptfs_flush,
394 .release = ecryptfs_release,
395 .fsync = ecryptfs_fsync,
396 .fasync = ecryptfs_fasync,
e9f6a99c 397 .splice_read = generic_file_splice_read,
237fead6 398};