eCryptfs: Remove mmap from directory operations
[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>
28#include <linux/mount.h>
29#include <linux/pagemap.h>
30#include <linux/security.h>
237fead6 31#include <linux/compat.h>
0cc72dc7 32#include <linux/fs_stack.h>
dda6445e 33#include <linux/smp_lock.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{
50 int rc;
51 struct dentry *lower_dentry;
52 struct vfsmount *lower_vfsmount;
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) {
bd243a4b
JJS
63 lower_dentry = ecryptfs_dentry_to_lower(file->f_path.dentry);
64 lower_vfsmount = ecryptfs_dentry_to_lower_mnt(file->f_path.dentry);
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65 touch_atime(lower_vfsmount, lower_dentry);
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++;
addd65ad
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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;
bd243a4b 122 inode = file->f_path.dentry->d_inode;
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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
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136 fsstack_copy_attr_atime(inode,
137 lower_file->f_path.dentry->d_inode);
138out:
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139 return rc;
140}
141
142struct kmem_cache *ecryptfs_file_info_cache;
143
144/**
145 * ecryptfs_open
146 * @inode: inode speciying file to open
147 * @file: Structure to return filled in
148 *
149 * Opens the file specified by inode.
150 *
151 * Returns zero on success; non-zero otherwise
152 */
153static int ecryptfs_open(struct inode *inode, struct file *file)
154{
155 int rc = 0;
156 struct ecryptfs_crypt_stat *crypt_stat = NULL;
157 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
bd243a4b 158 struct dentry *ecryptfs_dentry = file->f_path.dentry;
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159 /* Private value of ecryptfs_dentry allocated in
160 * ecryptfs_lookup() */
161 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
237fead6 162 struct ecryptfs_file_info *file_info;
237fead6 163
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MH
164 mount_crypt_stat = &ecryptfs_superblock_to_private(
165 ecryptfs_dentry->d_sb)->mount_crypt_stat;
166 if ((mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
167 && ((file->f_flags & O_WRONLY) || (file->f_flags & O_RDWR)
168 || (file->f_flags & O_CREAT) || (file->f_flags & O_TRUNC)
169 || (file->f_flags & O_APPEND))) {
170 printk(KERN_WARNING "Mount has encrypted view enabled; "
171 "files may only be read\n");
172 rc = -EPERM;
173 goto out;
174 }
237fead6 175 /* Released in ecryptfs_release or end of function if failure */
c3762229 176 file_info = kmem_cache_zalloc(ecryptfs_file_info_cache, GFP_KERNEL);
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177 ecryptfs_set_file_private(file, file_info);
178 if (!file_info) {
179 ecryptfs_printk(KERN_ERR,
180 "Error attempting to allocate memory\n");
181 rc = -ENOMEM;
182 goto out;
183 }
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184 lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
185 crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
237fead6 186 mutex_lock(&crypt_stat->cs_mutex);
e2bd99ec 187 if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)) {
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188 ecryptfs_printk(KERN_DEBUG, "Setting flags for stat...\n");
189 /* Policy code enabled in future release */
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190 crypt_stat->flags |= (ECRYPTFS_POLICY_APPLIED
191 | ECRYPTFS_ENCRYPTED);
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192 }
193 mutex_unlock(&crypt_stat->cs_mutex);
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194 if ((ecryptfs_inode_to_private(inode)->lower_file->f_flags & O_RDONLY)
195 && !(file->f_flags & O_RDONLY)) {
196 rc = -EPERM;
197 printk(KERN_WARNING "%s: Lower persistent file is RO; eCryptfs "
198 "file must hence be opened RO\n", __func__);
199 goto out;
200 }
72b55fff 201 if (!ecryptfs_inode_to_private(inode)->lower_file) {
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202 rc = ecryptfs_init_persistent_file(ecryptfs_dentry);
203 if (rc) {
204 printk(KERN_ERR "%s: Error attempting to initialize "
205 "the persistent file for the dentry with name "
206 "[%s]; rc = [%d]\n", __func__,
207 ecryptfs_dentry->d_name.name, rc);
208 goto out;
209 }
210 }
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211 ecryptfs_set_file_lower(
212 file, ecryptfs_inode_to_private(inode)->lower_file);
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213 if (S_ISDIR(ecryptfs_dentry->d_inode->i_mode)) {
214 ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
2f9b12a3 215 mutex_lock(&crypt_stat->cs_mutex);
e2bd99ec 216 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
2f9b12a3 217 mutex_unlock(&crypt_stat->cs_mutex);
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218 rc = 0;
219 goto out;
220 }
221 mutex_lock(&crypt_stat->cs_mutex);
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222 if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)
223 || !(crypt_stat->flags & ECRYPTFS_KEY_VALID)) {
d7cdc5fe 224 rc = ecryptfs_read_metadata(ecryptfs_dentry);
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225 if (rc) {
226 ecryptfs_printk(KERN_DEBUG,
227 "Valid headers not found\n");
228 if (!(mount_crypt_stat->flags
229 & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) {
230 rc = -EIO;
25bd8174 231 printk(KERN_WARNING "Either the lower file "
237fead6 232 "is not in a valid eCryptfs format, "
25bd8174
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233 "or the key could not be retrieved. "
234 "Plaintext passthrough mode is not "
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235 "enabled; returning -EIO\n");
236 mutex_unlock(&crypt_stat->cs_mutex);
2ed92554 237 goto out_free;
237fead6 238 }
237fead6 239 rc = 0;
e2bd99ec 240 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
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241 mutex_unlock(&crypt_stat->cs_mutex);
242 goto out;
243 }
244 }
245 mutex_unlock(&crypt_stat->cs_mutex);
246 ecryptfs_printk(KERN_DEBUG, "inode w/ addr = [0x%p], i_ino = [0x%.16x] "
247 "size: [0x%.16x]\n", inode, inode->i_ino,
248 i_size_read(inode));
237fead6 249 goto out;
2ed92554 250out_free:
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251 kmem_cache_free(ecryptfs_file_info_cache,
252 ecryptfs_file_to_private(file));
253out:
254 return rc;
255}
256
257static int ecryptfs_flush(struct file *file, fl_owner_t td)
258{
259 int rc = 0;
260 struct file *lower_file = NULL;
261
262 lower_file = ecryptfs_file_to_lower(file);
263 if (lower_file->f_op && lower_file->f_op->flush)
264 rc = lower_file->f_op->flush(lower_file, td);
265 return rc;
266}
267
268static int ecryptfs_release(struct inode *inode, struct file *file)
269{
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270 kmem_cache_free(ecryptfs_file_info_cache,
271 ecryptfs_file_to_private(file));
272 return 0;
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273}
274
275static int
276ecryptfs_fsync(struct file *file, struct dentry *dentry, int datasync)
277{
4c728ef5
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278 return vfs_fsync(ecryptfs_file_to_lower(file),
279 ecryptfs_dentry_to_lower(dentry),
280 datasync);
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281}
282
283static int ecryptfs_fasync(int fd, struct file *file, int flag)
284{
285 int rc = 0;
286 struct file *lower_file = NULL;
287
dda6445e 288 lock_kernel();
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289 lower_file = ecryptfs_file_to_lower(file);
290 if (lower_file->f_op && lower_file->f_op->fasync)
291 rc = lower_file->f_op->fasync(fd, lower_file, flag);
dda6445e 292 unlock_kernel();
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293 return rc;
294}
295
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296static int ecryptfs_ioctl(struct inode *inode, struct file *file,
297 unsigned int cmd, unsigned long arg);
298
299const struct file_operations ecryptfs_dir_fops = {
300 .readdir = ecryptfs_readdir,
301 .ioctl = ecryptfs_ioctl,
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302 .open = ecryptfs_open,
303 .flush = ecryptfs_flush,
304 .release = ecryptfs_release,
305 .fsync = ecryptfs_fsync,
306 .fasync = ecryptfs_fasync,
e9f6a99c 307 .splice_read = generic_file_splice_read,
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308};
309
310const struct file_operations ecryptfs_main_fops = {
53a2731f 311 .llseek = generic_file_llseek,
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312 .read = do_sync_read,
313 .aio_read = ecryptfs_read_update_atime,
314 .write = do_sync_write,
315 .aio_write = generic_file_aio_write,
316 .readdir = ecryptfs_readdir,
317 .ioctl = ecryptfs_ioctl,
318 .mmap = generic_file_mmap,
319 .open = ecryptfs_open,
320 .flush = ecryptfs_flush,
321 .release = ecryptfs_release,
322 .fsync = ecryptfs_fsync,
323 .fasync = ecryptfs_fasync,
e9f6a99c 324 .splice_read = generic_file_splice_read,
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325};
326
327static int
328ecryptfs_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
329 unsigned long arg)
330{
331 int rc = 0;
332 struct file *lower_file = NULL;
333
334 if (ecryptfs_file_to_private(file))
335 lower_file = ecryptfs_file_to_lower(file);
336 if (lower_file && lower_file->f_op && lower_file->f_op->ioctl)
337 rc = lower_file->f_op->ioctl(ecryptfs_inode_to_lower(inode),
338 lower_file, cmd, arg);
339 else
340 rc = -ENOTTY;
341 return rc;
342}