2 * eCryptfs: Linux filesystem encryption layer
4 * Copyright (C) 1997-2004 Erez Zadok
5 * Copyright (C) 2001-2004 Stony Brook University
6 * Copyright (C) 2004-2007 International Business Machines Corp.
7 * Author(s): Michael A. Halcrow <mhalcrow@us.ibm.com>
8 * Michael C. Thompson <mcthomps@us.ibm.com>
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.
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.
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
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>
31 #include <linux/compat.h>
32 #include <linux/fs_stack.h>
33 #include <linux/smp_lock.h>
34 #include "ecryptfs_kernel.h"
37 * ecryptfs_read_update_atime
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.
46 static ssize_t ecryptfs_read_update_atime(struct kiocb *iocb,
47 const struct iovec *iov,
48 unsigned long nr_segs, loff_t pos)
51 struct dentry *lower_dentry;
52 struct vfsmount *lower_vfsmount;
53 struct file *file = iocb->ki_filp;
55 rc = generic_file_aio_read(iocb, iov, nr_segs, pos);
57 * Even though this is a async interface, we need to wait
58 * for IO to finish to update atime
60 if (-EIOCBQUEUED == rc)
61 rc = wait_on_sync_kiocb(iocb);
63 lower_dentry = ecryptfs_dentry_to_lower(file->f_path.dentry);
64 lower_vfsmount = ecryptfs_dentry_to_lower_mnt(file->f_path.dentry);
65 touch_atime(lower_vfsmount, lower_dentry);
70 struct ecryptfs_getdents_callback {
72 struct dentry *dentry;
79 /* Inspired by generic filldir in fs/readir.c */
81 ecryptfs_filldir(void *dirent, const char *name, int namelen, loff_t offset,
82 u64 ino, unsigned int d_type)
84 struct ecryptfs_crypt_stat *crypt_stat;
85 struct ecryptfs_getdents_callback *buf =
86 (struct ecryptfs_getdents_callback *)dirent;
91 crypt_stat = ecryptfs_dentry_to_private(buf->dentry)->crypt_stat;
92 buf->filldir_called++;
93 decoded_length = ecryptfs_decode_filename(crypt_stat, name, namelen,
95 if (decoded_length < 0) {
99 rc = buf->filldir(buf->dirent, decoded_name, decoded_length, offset,
103 buf->entries_written++;
110 * @file: The ecryptfs file struct
111 * @dirent: Directory entry
112 * @filldir: The filldir callback function
114 static int ecryptfs_readdir(struct file *file, void *dirent, filldir_t filldir)
117 struct file *lower_file;
119 struct ecryptfs_getdents_callback buf;
121 lower_file = ecryptfs_file_to_lower(file);
122 lower_file->f_pos = file->f_pos;
123 inode = file->f_path.dentry->d_inode;
124 memset(&buf, 0, sizeof(buf));
126 buf.dentry = file->f_path.dentry;
127 buf.filldir = filldir;
129 buf.filldir_called = 0;
130 buf.entries_written = 0;
132 rc = vfs_readdir(lower_file, ecryptfs_filldir, (void *)&buf);
135 if (buf.filldir_called && !buf.entries_written)
137 file->f_pos = lower_file->f_pos;
139 fsstack_copy_attr_atime(inode, lower_file->f_path.dentry->d_inode);
143 struct kmem_cache *ecryptfs_file_info_cache;
147 * @inode: inode speciying file to open
148 * @file: Structure to return filled in
150 * Opens the file specified by inode.
152 * Returns zero on success; non-zero otherwise
154 static int ecryptfs_open(struct inode *inode, struct file *file)
157 struct ecryptfs_crypt_stat *crypt_stat = NULL;
158 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
159 struct dentry *ecryptfs_dentry = file->f_path.dentry;
160 /* Private value of ecryptfs_dentry allocated in
161 * ecryptfs_lookup() */
162 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
163 struct ecryptfs_file_info *file_info;
165 mount_crypt_stat = &ecryptfs_superblock_to_private(
166 ecryptfs_dentry->d_sb)->mount_crypt_stat;
167 if ((mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
168 && ((file->f_flags & O_WRONLY) || (file->f_flags & O_RDWR)
169 || (file->f_flags & O_CREAT) || (file->f_flags & O_TRUNC)
170 || (file->f_flags & O_APPEND))) {
171 printk(KERN_WARNING "Mount has encrypted view enabled; "
172 "files may only be read\n");
176 /* Released in ecryptfs_release or end of function if failure */
177 file_info = kmem_cache_zalloc(ecryptfs_file_info_cache, GFP_KERNEL);
178 ecryptfs_set_file_private(file, file_info);
180 ecryptfs_printk(KERN_ERR,
181 "Error attempting to allocate memory\n");
185 lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
186 crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
187 mutex_lock(&crypt_stat->cs_mutex);
188 if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)) {
189 ecryptfs_printk(KERN_DEBUG, "Setting flags for stat...\n");
190 /* Policy code enabled in future release */
191 crypt_stat->flags |= (ECRYPTFS_POLICY_APPLIED
192 | ECRYPTFS_ENCRYPTED);
194 mutex_unlock(&crypt_stat->cs_mutex);
195 if ((ecryptfs_inode_to_private(inode)->lower_file->f_flags & O_RDONLY)
196 && !(file->f_flags & O_RDONLY)) {
198 printk(KERN_WARNING "%s: Lower persistent file is RO; eCryptfs "
199 "file must hence be opened RO\n", __func__);
202 if (!ecryptfs_inode_to_private(inode)->lower_file) {
203 BUG_ON(!(crypt_stat->flags & ECRYPTFS_DELAY_PERSISTENT));
204 mutex_lock(&crypt_stat->cs_mutex);
205 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
206 mutex_unlock(&crypt_stat->cs_mutex);
207 rc = ecryptfs_init_persistent_file(ecryptfs_dentry);
209 printk(KERN_ERR "%s: Error attempting to initialize "
210 "the persistent file for the dentry with name "
211 "[%s]; rc = [%d]\n", __func__,
212 ecryptfs_dentry->d_name.name, rc);
216 ecryptfs_set_file_lower(
217 file, ecryptfs_inode_to_private(inode)->lower_file);
218 if (S_ISDIR(ecryptfs_dentry->d_inode->i_mode)) {
219 ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
220 mutex_lock(&crypt_stat->cs_mutex);
221 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
222 mutex_unlock(&crypt_stat->cs_mutex);
226 mutex_lock(&crypt_stat->cs_mutex);
227 if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)
228 || !(crypt_stat->flags & ECRYPTFS_KEY_VALID)) {
229 rc = ecryptfs_read_metadata(ecryptfs_dentry);
231 ecryptfs_printk(KERN_DEBUG,
232 "Valid headers not found\n");
233 if (!(mount_crypt_stat->flags
234 & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) {
236 printk(KERN_WARNING "Either the lower file "
237 "is not in a valid eCryptfs format, "
238 "or the key could not be retrieved. "
239 "Plaintext passthrough mode is not "
240 "enabled; returning -EIO\n");
241 mutex_unlock(&crypt_stat->cs_mutex);
245 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
246 mutex_unlock(&crypt_stat->cs_mutex);
250 mutex_unlock(&crypt_stat->cs_mutex);
251 ecryptfs_printk(KERN_DEBUG, "inode w/ addr = [0x%p], i_ino = [0x%.16x] "
252 "size: [0x%.16x]\n", inode, inode->i_ino,
256 kmem_cache_free(ecryptfs_file_info_cache,
257 ecryptfs_file_to_private(file));
262 static int ecryptfs_flush(struct file *file, fl_owner_t td)
265 struct file *lower_file = NULL;
267 lower_file = ecryptfs_file_to_lower(file);
268 if (lower_file->f_op && lower_file->f_op->flush)
269 rc = lower_file->f_op->flush(lower_file, td);
273 static int ecryptfs_release(struct inode *inode, struct file *file)
275 kmem_cache_free(ecryptfs_file_info_cache,
276 ecryptfs_file_to_private(file));
281 ecryptfs_fsync(struct file *file, struct dentry *dentry, int datasync)
283 struct file *lower_file = ecryptfs_file_to_lower(file);
284 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
285 struct inode *lower_inode = lower_dentry->d_inode;
288 if (lower_inode->i_fop->fsync) {
289 mutex_lock(&lower_inode->i_mutex);
290 rc = lower_inode->i_fop->fsync(lower_file, lower_dentry,
292 mutex_unlock(&lower_inode->i_mutex);
297 static int ecryptfs_fasync(int fd, struct file *file, int flag)
300 struct file *lower_file = NULL;
303 lower_file = ecryptfs_file_to_lower(file);
304 if (lower_file->f_op && lower_file->f_op->fasync)
305 rc = lower_file->f_op->fasync(fd, lower_file, flag);
310 static int ecryptfs_ioctl(struct inode *inode, struct file *file,
311 unsigned int cmd, unsigned long arg);
313 const struct file_operations ecryptfs_dir_fops = {
314 .readdir = ecryptfs_readdir,
315 .ioctl = ecryptfs_ioctl,
316 .mmap = generic_file_mmap,
317 .open = ecryptfs_open,
318 .flush = ecryptfs_flush,
319 .release = ecryptfs_release,
320 .fsync = ecryptfs_fsync,
321 .fasync = ecryptfs_fasync,
322 .splice_read = generic_file_splice_read,
325 const struct file_operations ecryptfs_main_fops = {
326 .llseek = generic_file_llseek,
327 .read = do_sync_read,
328 .aio_read = ecryptfs_read_update_atime,
329 .write = do_sync_write,
330 .aio_write = generic_file_aio_write,
331 .readdir = ecryptfs_readdir,
332 .ioctl = ecryptfs_ioctl,
333 .mmap = generic_file_mmap,
334 .open = ecryptfs_open,
335 .flush = ecryptfs_flush,
336 .release = ecryptfs_release,
337 .fsync = ecryptfs_fsync,
338 .fasync = ecryptfs_fasync,
339 .splice_read = generic_file_splice_read,
343 ecryptfs_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
347 struct file *lower_file = NULL;
349 if (ecryptfs_file_to_private(file))
350 lower_file = ecryptfs_file_to_lower(file);
351 if (lower_file && lower_file->f_op && lower_file->f_op->ioctl)
352 rc = lower_file->f_op->ioctl(ecryptfs_inode_to_lower(inode),
353 lower_file, cmd, arg);