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 {
71 struct dir_context ctx;
72 struct dir_context *caller;
73 struct super_block *sb;
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,
94 printk(KERN_ERR "%s: Error attempting to decode and decrypt "
95 "filename [%s]; rc = [%d]\n", __func__, lower_name,
99 buf->caller->pos = buf->ctx.pos;
100 rc = !dir_emit(buf->caller, name, name_size, ino, d_type);
103 buf->entries_written++;
110 * @file: The eCryptfs directory file
111 * @ctx: The actor to feed the entries to
113 static int ecryptfs_readdir(struct file *file, struct dir_context *ctx)
116 struct file *lower_file;
117 struct inode *inode = file_inode(file);
118 struct ecryptfs_getdents_callback buf = {
119 .ctx.actor = ecryptfs_filldir,
123 lower_file = ecryptfs_file_to_lower(file);
124 lower_file->f_pos = ctx->pos;
125 rc = iterate_dir(lower_file, &buf.ctx);
126 ctx->pos = buf.ctx.pos;
129 if (buf.filldir_called && !buf.entries_written)
132 fsstack_copy_attr_atime(inode,
133 file_inode(lower_file));
138 struct kmem_cache *ecryptfs_file_info_cache;
140 static int read_or_initialize_metadata(struct dentry *dentry)
142 struct inode *inode = dentry->d_inode;
143 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
144 struct ecryptfs_crypt_stat *crypt_stat;
147 crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
148 mount_crypt_stat = &ecryptfs_superblock_to_private(
149 inode->i_sb)->mount_crypt_stat;
150 mutex_lock(&crypt_stat->cs_mutex);
152 if (crypt_stat->flags & ECRYPTFS_POLICY_APPLIED &&
153 crypt_stat->flags & ECRYPTFS_KEY_VALID) {
158 rc = ecryptfs_read_metadata(dentry);
162 if (mount_crypt_stat->flags & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED) {
163 crypt_stat->flags &= ~(ECRYPTFS_I_SIZE_INITIALIZED
164 | ECRYPTFS_ENCRYPTED);
169 if (!(mount_crypt_stat->flags & ECRYPTFS_XATTR_METADATA_ENABLED) &&
170 !i_size_read(ecryptfs_inode_to_lower(inode))) {
171 rc = ecryptfs_initialize_file(dentry, inode);
178 mutex_unlock(&crypt_stat->cs_mutex);
184 * @inode: inode speciying file to open
185 * @file: Structure to return filled in
187 * Opens the file specified by inode.
189 * Returns zero on success; non-zero otherwise
191 static int ecryptfs_open(struct inode *inode, struct file *file)
194 struct ecryptfs_crypt_stat *crypt_stat = NULL;
195 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
196 struct dentry *ecryptfs_dentry = file->f_path.dentry;
197 /* Private value of ecryptfs_dentry allocated in
198 * ecryptfs_lookup() */
199 struct ecryptfs_file_info *file_info;
201 mount_crypt_stat = &ecryptfs_superblock_to_private(
202 ecryptfs_dentry->d_sb)->mount_crypt_stat;
203 if ((mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
204 && ((file->f_flags & O_WRONLY) || (file->f_flags & O_RDWR)
205 || (file->f_flags & O_CREAT) || (file->f_flags & O_TRUNC)
206 || (file->f_flags & O_APPEND))) {
207 printk(KERN_WARNING "Mount has encrypted view enabled; "
208 "files may only be read\n");
212 /* Released in ecryptfs_release or end of function if failure */
213 file_info = kmem_cache_zalloc(ecryptfs_file_info_cache, GFP_KERNEL);
214 ecryptfs_set_file_private(file, file_info);
216 ecryptfs_printk(KERN_ERR,
217 "Error attempting to allocate memory\n");
221 crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
222 mutex_lock(&crypt_stat->cs_mutex);
223 if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)) {
224 ecryptfs_printk(KERN_DEBUG, "Setting flags for stat...\n");
225 /* Policy code enabled in future release */
226 crypt_stat->flags |= (ECRYPTFS_POLICY_APPLIED
227 | ECRYPTFS_ENCRYPTED);
229 mutex_unlock(&crypt_stat->cs_mutex);
230 rc = ecryptfs_get_lower_file(ecryptfs_dentry, inode);
232 printk(KERN_ERR "%s: Error attempting to initialize "
233 "the lower file for the dentry with name "
234 "[%s]; rc = [%d]\n", __func__,
235 ecryptfs_dentry->d_name.name, rc);
238 if ((ecryptfs_inode_to_private(inode)->lower_file->f_flags & O_ACCMODE)
239 == O_RDONLY && (file->f_flags & O_ACCMODE) != O_RDONLY) {
241 printk(KERN_WARNING "%s: Lower file is RO; eCryptfs "
242 "file must hence be opened RO\n", __func__);
245 ecryptfs_set_file_lower(
246 file, ecryptfs_inode_to_private(inode)->lower_file);
247 if (S_ISDIR(ecryptfs_dentry->d_inode->i_mode)) {
248 ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
249 mutex_lock(&crypt_stat->cs_mutex);
250 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
251 mutex_unlock(&crypt_stat->cs_mutex);
255 rc = read_or_initialize_metadata(ecryptfs_dentry);
258 ecryptfs_printk(KERN_DEBUG, "inode w/ addr = [0x%p], i_ino = "
259 "[0x%.16lx] size: [0x%.16llx]\n", inode, inode->i_ino,
260 (unsigned long long)i_size_read(inode));
263 ecryptfs_put_lower_file(inode);
265 kmem_cache_free(ecryptfs_file_info_cache,
266 ecryptfs_file_to_private(file));
271 static int ecryptfs_flush(struct file *file, fl_owner_t td)
273 struct file *lower_file = ecryptfs_file_to_lower(file);
275 if (lower_file->f_op && lower_file->f_op->flush) {
276 filemap_write_and_wait(file->f_mapping);
277 return lower_file->f_op->flush(lower_file, td);
283 static int ecryptfs_release(struct inode *inode, struct file *file)
285 ecryptfs_put_lower_file(inode);
286 kmem_cache_free(ecryptfs_file_info_cache,
287 ecryptfs_file_to_private(file));
292 ecryptfs_fsync(struct file *file, loff_t start, loff_t end, int datasync)
296 rc = filemap_write_and_wait(file->f_mapping);
300 return vfs_fsync(ecryptfs_file_to_lower(file), datasync);
303 static int ecryptfs_fasync(int fd, struct file *file, int flag)
306 struct file *lower_file = NULL;
308 lower_file = ecryptfs_file_to_lower(file);
309 if (lower_file->f_op && lower_file->f_op->fasync)
310 rc = lower_file->f_op->fasync(fd, lower_file, flag);
315 ecryptfs_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
317 struct file *lower_file = NULL;
320 if (ecryptfs_file_to_private(file))
321 lower_file = ecryptfs_file_to_lower(file);
322 if (lower_file && lower_file->f_op && lower_file->f_op->unlocked_ioctl)
323 rc = lower_file->f_op->unlocked_ioctl(lower_file, cmd, arg);
329 ecryptfs_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
331 struct file *lower_file = NULL;
332 long rc = -ENOIOCTLCMD;
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->compat_ioctl)
337 rc = lower_file->f_op->compat_ioctl(lower_file, cmd, arg);
342 const struct file_operations ecryptfs_dir_fops = {
343 .iterate = ecryptfs_readdir,
344 .read = generic_read_dir,
345 .unlocked_ioctl = ecryptfs_unlocked_ioctl,
347 .compat_ioctl = ecryptfs_compat_ioctl,
349 .open = ecryptfs_open,
350 .flush = ecryptfs_flush,
351 .release = ecryptfs_release,
352 .fsync = ecryptfs_fsync,
353 .fasync = ecryptfs_fasync,
354 .splice_read = generic_file_splice_read,
355 .llseek = default_llseek,
358 const struct file_operations ecryptfs_main_fops = {
359 .llseek = generic_file_llseek,
360 .read = do_sync_read,
361 .aio_read = ecryptfs_read_update_atime,
362 .write = do_sync_write,
363 .aio_write = generic_file_aio_write,
364 .iterate = ecryptfs_readdir,
365 .unlocked_ioctl = ecryptfs_unlocked_ioctl,
367 .compat_ioctl = ecryptfs_compat_ioctl,
369 .mmap = generic_file_mmap,
370 .open = ecryptfs_open,
371 .flush = ecryptfs_flush,
372 .release = ecryptfs_release,
373 .fsync = ecryptfs_fsync,
374 .fasync = ecryptfs_fasync,
375 .splice_read = generic_file_splice_read,