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/aio.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)
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.mnt = ecryptfs_dentry_to_lower_mnt(file->f_path.dentry);
70 struct ecryptfs_getdents_callback {
72 struct dentry *dentry;
78 /* Inspired by generic filldir in fs/readdir.c */
80 ecryptfs_filldir(void *dirent, const char *lower_name, int lower_namelen,
81 loff_t offset, u64 ino, unsigned int d_type)
83 struct ecryptfs_getdents_callback *buf =
84 (struct ecryptfs_getdents_callback *)dirent;
89 buf->filldir_called++;
90 rc = ecryptfs_decode_and_decrypt_filename(&name, &name_size,
91 buf->dentry, lower_name,
94 printk(KERN_ERR "%s: Error attempting to decode and decrypt "
95 "filename [%s]; rc = [%d]\n", __func__, lower_name,
99 rc = buf->filldir(buf->dirent, name, name_size, offset, ino, d_type);
102 buf->entries_written++;
109 * @file: The eCryptfs directory file
110 * @dirent: Directory entry handle
111 * @filldir: The filldir callback function
113 static int ecryptfs_readdir(struct file *file, void *dirent, filldir_t filldir)
116 struct file *lower_file;
118 struct ecryptfs_getdents_callback buf;
120 lower_file = ecryptfs_file_to_lower(file);
121 lower_file->f_pos = file->f_pos;
122 inode = file_inode(file);
123 memset(&buf, 0, sizeof(buf));
125 buf.dentry = file->f_path.dentry;
126 buf.filldir = filldir;
127 buf.filldir_called = 0;
128 buf.entries_written = 0;
129 rc = vfs_readdir(lower_file, ecryptfs_filldir, (void *)&buf);
130 file->f_pos = lower_file->f_pos;
133 if (buf.filldir_called && !buf.entries_written)
136 fsstack_copy_attr_atime(inode,
137 file_inode(lower_file));
142 struct kmem_cache *ecryptfs_file_info_cache;
144 static int read_or_initialize_metadata(struct dentry *dentry)
146 struct inode *inode = dentry->d_inode;
147 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
148 struct ecryptfs_crypt_stat *crypt_stat;
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);
156 if (crypt_stat->flags & ECRYPTFS_POLICY_APPLIED &&
157 crypt_stat->flags & ECRYPTFS_KEY_VALID) {
162 rc = ecryptfs_read_metadata(dentry);
166 if (mount_crypt_stat->flags & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED) {
167 crypt_stat->flags &= ~(ECRYPTFS_I_SIZE_INITIALIZED
168 | ECRYPTFS_ENCRYPTED);
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);
182 mutex_unlock(&crypt_stat->cs_mutex);
188 * @inode: inode speciying file to open
189 * @file: Structure to return filled in
191 * Opens the file specified by inode.
193 * Returns zero on success; non-zero otherwise
195 static int ecryptfs_open(struct inode *inode, struct file *file)
198 struct ecryptfs_crypt_stat *crypt_stat = NULL;
199 struct dentry *ecryptfs_dentry = file->f_path.dentry;
200 /* Private value of ecryptfs_dentry allocated in
201 * ecryptfs_lookup() */
202 struct ecryptfs_file_info *file_info;
204 /* Released in ecryptfs_release or end of function if failure */
205 file_info = kmem_cache_zalloc(ecryptfs_file_info_cache, GFP_KERNEL);
206 ecryptfs_set_file_private(file, file_info);
208 ecryptfs_printk(KERN_ERR,
209 "Error attempting to allocate memory\n");
213 crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
214 mutex_lock(&crypt_stat->cs_mutex);
215 if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)) {
216 ecryptfs_printk(KERN_DEBUG, "Setting flags for stat...\n");
217 /* Policy code enabled in future release */
218 crypt_stat->flags |= (ECRYPTFS_POLICY_APPLIED
219 | ECRYPTFS_ENCRYPTED);
221 mutex_unlock(&crypt_stat->cs_mutex);
222 rc = ecryptfs_get_lower_file(ecryptfs_dentry, inode);
224 printk(KERN_ERR "%s: Error attempting to initialize "
225 "the lower file for the dentry with name "
226 "[%s]; rc = [%d]\n", __func__,
227 ecryptfs_dentry->d_name.name, rc);
230 if ((ecryptfs_inode_to_private(inode)->lower_file->f_flags & O_ACCMODE)
231 == O_RDONLY && (file->f_flags & O_ACCMODE) != O_RDONLY) {
233 printk(KERN_WARNING "%s: Lower file is RO; eCryptfs "
234 "file must hence be opened RO\n", __func__);
237 ecryptfs_set_file_lower(
238 file, ecryptfs_inode_to_private(inode)->lower_file);
239 if (S_ISDIR(ecryptfs_dentry->d_inode->i_mode)) {
240 ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
241 mutex_lock(&crypt_stat->cs_mutex);
242 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
243 mutex_unlock(&crypt_stat->cs_mutex);
247 rc = read_or_initialize_metadata(ecryptfs_dentry);
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));
255 ecryptfs_put_lower_file(inode);
257 kmem_cache_free(ecryptfs_file_info_cache,
258 ecryptfs_file_to_private(file));
263 static int ecryptfs_flush(struct file *file, fl_owner_t td)
265 struct file *lower_file = ecryptfs_file_to_lower(file);
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);
275 static int ecryptfs_release(struct inode *inode, struct file *file)
277 ecryptfs_put_lower_file(inode);
278 kmem_cache_free(ecryptfs_file_info_cache,
279 ecryptfs_file_to_private(file));
284 ecryptfs_fsync(struct file *file, loff_t start, loff_t end, int datasync)
288 rc = filemap_write_and_wait(file->f_mapping);
292 return vfs_fsync(ecryptfs_file_to_lower(file), datasync);
295 static int ecryptfs_fasync(int fd, struct file *file, int flag)
298 struct file *lower_file = NULL;
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);
307 ecryptfs_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
309 struct file *lower_file = NULL;
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);
321 ecryptfs_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
323 struct file *lower_file = NULL;
324 long rc = -ENOIOCTLCMD;
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);
334 const struct file_operations ecryptfs_dir_fops = {
335 .readdir = ecryptfs_readdir,
336 .read = generic_read_dir,
337 .unlocked_ioctl = ecryptfs_unlocked_ioctl,
339 .compat_ioctl = ecryptfs_compat_ioctl,
341 .open = ecryptfs_open,
342 .flush = ecryptfs_flush,
343 .release = ecryptfs_release,
344 .fsync = ecryptfs_fsync,
345 .fasync = ecryptfs_fasync,
346 .splice_read = generic_file_splice_read,
347 .llseek = default_llseek,
350 const struct file_operations ecryptfs_main_fops = {
351 .llseek = generic_file_llseek,
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,
357 .unlocked_ioctl = ecryptfs_unlocked_ioctl,
359 .compat_ioctl = ecryptfs_compat_ioctl,
361 .mmap = generic_file_mmap,
362 .open = ecryptfs_open,
363 .flush = ecryptfs_flush,
364 .release = ecryptfs_release,
365 .fsync = ecryptfs_fsync,
366 .fasync = ecryptfs_fasync,
367 .splice_read = generic_file_splice_read,