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 "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)
52 struct file *file = iocb->ki_filp;
54 rc = generic_file_aio_read(iocb, iov, nr_segs, pos);
56 * Even though this is a async interface, we need to wait
57 * for IO to finish to update atime
59 if (-EIOCBQUEUED == rc)
60 rc = wait_on_sync_kiocb(iocb);
62 lower.dentry = ecryptfs_dentry_to_lower(file->f_path.dentry);
63 lower.mnt = ecryptfs_dentry_to_lower_mnt(file->f_path.dentry);
69 struct ecryptfs_getdents_callback {
71 struct dentry *dentry;
77 /* Inspired by generic filldir in fs/readdir.c */
79 ecryptfs_filldir(void *dirent, const char *lower_name, int lower_namelen,
80 loff_t offset, u64 ino, unsigned int d_type)
82 struct ecryptfs_getdents_callback *buf =
83 (struct ecryptfs_getdents_callback *)dirent;
88 buf->filldir_called++;
89 rc = ecryptfs_decode_and_decrypt_filename(&name, &name_size,
90 buf->dentry, lower_name,
93 printk(KERN_ERR "%s: Error attempting to decode and decrypt "
94 "filename [%s]; rc = [%d]\n", __func__, lower_name,
98 rc = buf->filldir(buf->dirent, name, name_size, offset, ino, d_type);
101 buf->entries_written++;
108 * @file: The eCryptfs directory file
109 * @dirent: Directory entry handle
110 * @filldir: The filldir callback function
112 static int ecryptfs_readdir(struct file *file, void *dirent, filldir_t filldir)
115 struct file *lower_file;
117 struct ecryptfs_getdents_callback buf;
119 lower_file = ecryptfs_file_to_lower(file);
120 lower_file->f_pos = file->f_pos;
121 inode = file->f_path.dentry->d_inode;
122 memset(&buf, 0, sizeof(buf));
124 buf.dentry = file->f_path.dentry;
125 buf.filldir = filldir;
126 buf.filldir_called = 0;
127 buf.entries_written = 0;
128 rc = vfs_readdir(lower_file, ecryptfs_filldir, (void *)&buf);
129 file->f_pos = lower_file->f_pos;
132 if (buf.filldir_called && !buf.entries_written)
135 fsstack_copy_attr_atime(inode,
136 lower_file->f_path.dentry->d_inode);
141 static void ecryptfs_vma_close(struct vm_area_struct *vma)
143 filemap_write_and_wait(vma->vm_file->f_mapping);
146 static const struct vm_operations_struct ecryptfs_file_vm_ops = {
147 .close = ecryptfs_vma_close,
148 .fault = filemap_fault,
151 static int ecryptfs_file_mmap(struct file *file, struct vm_area_struct *vma)
155 rc = generic_file_mmap(file, vma);
157 vma->vm_ops = &ecryptfs_file_vm_ops;
162 struct kmem_cache *ecryptfs_file_info_cache;
164 static int read_or_initialize_metadata(struct dentry *dentry)
166 struct inode *inode = dentry->d_inode;
167 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
168 struct ecryptfs_crypt_stat *crypt_stat;
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);
176 if (crypt_stat->flags & ECRYPTFS_POLICY_APPLIED &&
177 crypt_stat->flags & ECRYPTFS_KEY_VALID) {
182 rc = ecryptfs_read_metadata(dentry);
186 if (mount_crypt_stat->flags & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED) {
187 crypt_stat->flags &= ~(ECRYPTFS_I_SIZE_INITIALIZED
188 | ECRYPTFS_ENCRYPTED);
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);
202 mutex_unlock(&crypt_stat->cs_mutex);
208 * @inode: inode speciying file to open
209 * @file: Structure to return filled in
211 * Opens the file specified by inode.
213 * Returns zero on success; non-zero otherwise
215 static int ecryptfs_open(struct inode *inode, struct file *file)
218 struct ecryptfs_crypt_stat *crypt_stat = NULL;
219 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
220 struct dentry *ecryptfs_dentry = file->f_path.dentry;
221 /* Private value of ecryptfs_dentry allocated in
222 * ecryptfs_lookup() */
223 struct dentry *lower_dentry;
224 struct ecryptfs_file_info *file_info;
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");
237 /* Released in ecryptfs_release or end of function if failure */
238 file_info = kmem_cache_zalloc(ecryptfs_file_info_cache, GFP_KERNEL);
239 ecryptfs_set_file_private(file, file_info);
241 ecryptfs_printk(KERN_ERR,
242 "Error attempting to allocate memory\n");
246 lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
247 crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
248 mutex_lock(&crypt_stat->cs_mutex);
249 if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)) {
250 ecryptfs_printk(KERN_DEBUG, "Setting flags for stat...\n");
251 /* Policy code enabled in future release */
252 crypt_stat->flags |= (ECRYPTFS_POLICY_APPLIED
253 | ECRYPTFS_ENCRYPTED);
255 mutex_unlock(&crypt_stat->cs_mutex);
256 rc = ecryptfs_get_lower_file(ecryptfs_dentry, inode);
258 printk(KERN_ERR "%s: Error attempting to initialize "
259 "the lower file for the dentry with name "
260 "[%s]; rc = [%d]\n", __func__,
261 ecryptfs_dentry->d_name.name, rc);
264 if ((ecryptfs_inode_to_private(inode)->lower_file->f_flags & O_ACCMODE)
265 == O_RDONLY && (file->f_flags & O_ACCMODE) != O_RDONLY) {
267 printk(KERN_WARNING "%s: Lower file is RO; eCryptfs "
268 "file must hence be opened RO\n", __func__);
271 ecryptfs_set_file_lower(
272 file, ecryptfs_inode_to_private(inode)->lower_file);
273 if (S_ISDIR(ecryptfs_dentry->d_inode->i_mode)) {
274 ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
275 mutex_lock(&crypt_stat->cs_mutex);
276 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
277 mutex_unlock(&crypt_stat->cs_mutex);
281 rc = read_or_initialize_metadata(ecryptfs_dentry);
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));
289 ecryptfs_put_lower_file(inode);
291 kmem_cache_free(ecryptfs_file_info_cache,
292 ecryptfs_file_to_private(file));
297 static int ecryptfs_flush(struct file *file, fl_owner_t td)
299 return file->f_mode & FMODE_WRITE
300 ? filemap_write_and_wait(file->f_mapping) : 0;
303 static int ecryptfs_release(struct inode *inode, struct file *file)
305 ecryptfs_put_lower_file(inode);
306 kmem_cache_free(ecryptfs_file_info_cache,
307 ecryptfs_file_to_private(file));
312 ecryptfs_fsync(struct file *file, loff_t start, loff_t end, int datasync)
316 rc = generic_file_fsync(file, start, end, datasync);
319 rc = vfs_fsync_range(ecryptfs_file_to_lower(file), start, end,
325 static int ecryptfs_fasync(int fd, struct file *file, int flag)
328 struct file *lower_file = NULL;
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);
337 ecryptfs_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
339 struct file *lower_file = NULL;
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);
351 ecryptfs_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
353 struct file *lower_file = NULL;
354 long rc = -ENOIOCTLCMD;
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);
364 const struct file_operations ecryptfs_dir_fops = {
365 .readdir = ecryptfs_readdir,
366 .read = generic_read_dir,
367 .unlocked_ioctl = ecryptfs_unlocked_ioctl,
369 .compat_ioctl = ecryptfs_compat_ioctl,
371 .open = ecryptfs_open,
372 .flush = ecryptfs_flush,
373 .release = ecryptfs_release,
374 .fsync = ecryptfs_fsync,
375 .fasync = ecryptfs_fasync,
376 .splice_read = generic_file_splice_read,
377 .llseek = default_llseek,
380 const struct file_operations ecryptfs_main_fops = {
381 .llseek = generic_file_llseek,
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,
387 .unlocked_ioctl = ecryptfs_unlocked_ioctl,
389 .compat_ioctl = ecryptfs_compat_ioctl,
391 .mmap = ecryptfs_file_mmap,
392 .open = ecryptfs_open,
393 .flush = ecryptfs_flush,
394 .release = ecryptfs_release,
395 .fsync = ecryptfs_fsync,
396 .fasync = ecryptfs_fasync,
397 .splice_read = generic_file_splice_read,