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/slab.h>
29 #include <linux/mount.h>
30 #include <linux/pagemap.h>
31 #include <linux/security.h>
32 #include <linux/compat.h>
33 #include <linux/fs_stack.h>
34 #include <linux/smp_lock.h>
35 #include "ecryptfs_kernel.h"
38 * ecryptfs_read_update_atime
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.
47 static ssize_t ecryptfs_read_update_atime(struct kiocb *iocb,
48 const struct iovec *iov,
49 unsigned long nr_segs, loff_t pos)
52 struct dentry *lower_dentry;
53 struct vfsmount *lower_vfsmount;
54 struct file *file = iocb->ki_filp;
56 rc = generic_file_aio_read(iocb, iov, nr_segs, pos);
58 * Even though this is a async interface, we need to wait
59 * for IO to finish to update atime
61 if (-EIOCBQUEUED == rc)
62 rc = wait_on_sync_kiocb(iocb);
64 lower_dentry = ecryptfs_dentry_to_lower(file->f_path.dentry);
65 lower_vfsmount = ecryptfs_dentry_to_lower_mnt(file->f_path.dentry);
66 touch_atime(lower_vfsmount, lower_dentry);
71 struct ecryptfs_getdents_callback {
73 struct dentry *dentry;
79 /* Inspired by generic filldir in fs/readdir.c */
81 ecryptfs_filldir(void *dirent, const char *lower_name, int lower_namelen,
82 loff_t offset, u64 ino, unsigned int d_type)
84 struct ecryptfs_getdents_callback *buf =
85 (struct ecryptfs_getdents_callback *)dirent;
90 buf->filldir_called++;
91 rc = ecryptfs_decode_and_decrypt_filename(&name, &name_size,
92 buf->dentry, lower_name,
95 printk(KERN_ERR "%s: Error attempting to decode and decrypt "
96 "filename [%s]; rc = [%d]\n", __func__, lower_name,
100 rc = buf->filldir(buf->dirent, name, name_size, offset, ino, d_type);
103 buf->entries_written++;
110 * @file: The eCryptfs directory file
111 * @dirent: Directory entry handle
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;
128 buf.filldir_called = 0;
129 buf.entries_written = 0;
130 rc = vfs_readdir(lower_file, ecryptfs_filldir, (void *)&buf);
131 file->f_pos = lower_file->f_pos;
134 if (buf.filldir_called && !buf.entries_written)
137 fsstack_copy_attr_atime(inode,
138 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;
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) {
196 rc = ecryptfs_init_persistent_file(ecryptfs_dentry);
198 printk(KERN_ERR "%s: Error attempting to initialize "
199 "the persistent file for the dentry with name "
200 "[%s]; rc = [%d]\n", __func__,
201 ecryptfs_dentry->d_name.name, rc);
205 if ((ecryptfs_inode_to_private(inode)->lower_file->f_flags & O_RDONLY)
206 && !(file->f_flags & O_RDONLY)) {
208 printk(KERN_WARNING "%s: Lower persistent file is RO; eCryptfs "
209 "file must hence be opened RO\n", __func__);
212 ecryptfs_set_file_lower(
213 file, ecryptfs_inode_to_private(inode)->lower_file);
214 if (S_ISDIR(ecryptfs_dentry->d_inode->i_mode)) {
215 ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
216 mutex_lock(&crypt_stat->cs_mutex);
217 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
218 mutex_unlock(&crypt_stat->cs_mutex);
222 mutex_lock(&crypt_stat->cs_mutex);
223 if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)
224 || !(crypt_stat->flags & ECRYPTFS_KEY_VALID)) {
225 rc = ecryptfs_read_metadata(ecryptfs_dentry);
227 ecryptfs_printk(KERN_DEBUG,
228 "Valid headers not found\n");
229 if (!(mount_crypt_stat->flags
230 & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) {
232 printk(KERN_WARNING "Either the lower file "
233 "is not in a valid eCryptfs format, "
234 "or the key could not be retrieved. "
235 "Plaintext passthrough mode is not "
236 "enabled; returning -EIO\n");
237 mutex_unlock(&crypt_stat->cs_mutex);
241 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
242 mutex_unlock(&crypt_stat->cs_mutex);
246 mutex_unlock(&crypt_stat->cs_mutex);
247 ecryptfs_printk(KERN_DEBUG, "inode w/ addr = [0x%p], i_ino = [0x%.16x] "
248 "size: [0x%.16x]\n", inode, inode->i_ino,
252 kmem_cache_free(ecryptfs_file_info_cache,
253 ecryptfs_file_to_private(file));
258 static int ecryptfs_flush(struct file *file, fl_owner_t td)
261 struct file *lower_file = NULL;
263 lower_file = ecryptfs_file_to_lower(file);
264 if (lower_file->f_op && lower_file->f_op->flush)
265 rc = lower_file->f_op->flush(lower_file, td);
269 static int ecryptfs_release(struct inode *inode, struct file *file)
271 kmem_cache_free(ecryptfs_file_info_cache,
272 ecryptfs_file_to_private(file));
277 ecryptfs_fsync(struct file *file, int datasync)
279 return vfs_fsync(ecryptfs_file_to_lower(file), datasync);
282 static int ecryptfs_fasync(int fd, struct file *file, int flag)
285 struct file *lower_file = NULL;
288 lower_file = ecryptfs_file_to_lower(file);
289 if (lower_file->f_op && lower_file->f_op->fasync)
290 rc = lower_file->f_op->fasync(fd, lower_file, flag);
295 static int ecryptfs_ioctl(struct inode *inode, struct file *file,
296 unsigned int cmd, unsigned long arg);
298 const struct file_operations ecryptfs_dir_fops = {
299 .readdir = ecryptfs_readdir,
300 .ioctl = ecryptfs_ioctl,
301 .open = ecryptfs_open,
302 .flush = ecryptfs_flush,
303 .release = ecryptfs_release,
304 .fsync = ecryptfs_fsync,
305 .fasync = ecryptfs_fasync,
306 .splice_read = generic_file_splice_read,
309 const struct file_operations ecryptfs_main_fops = {
310 .llseek = generic_file_llseek,
311 .read = do_sync_read,
312 .aio_read = ecryptfs_read_update_atime,
313 .write = do_sync_write,
314 .aio_write = generic_file_aio_write,
315 .readdir = ecryptfs_readdir,
316 .ioctl = ecryptfs_ioctl,
317 .mmap = generic_file_mmap,
318 .open = ecryptfs_open,
319 .flush = ecryptfs_flush,
320 .release = ecryptfs_release,
321 .fsync = ecryptfs_fsync,
322 .fasync = ecryptfs_fasync,
323 .splice_read = generic_file_splice_read,
327 ecryptfs_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
331 struct file *lower_file = NULL;
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->ioctl)
336 rc = lower_file->f_op->ioctl(ecryptfs_inode_to_lower(inode),
337 lower_file, cmd, arg);