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,
52 struct file *file = iocb->ki_filp;
54 rc = generic_file_read_iter(iocb, to);
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 path = ecryptfs_dentry_to_lower_path(file->f_path.dentry);
68 struct ecryptfs_getdents_callback {
69 struct dir_context ctx;
70 struct dir_context *caller;
71 struct super_block *sb;
76 /* Inspired by generic filldir in fs/readdir.c */
78 ecryptfs_filldir(struct dir_context *ctx, const char *lower_name,
79 int lower_namelen, loff_t offset, u64 ino, unsigned int d_type)
81 struct ecryptfs_getdents_callback *buf =
82 container_of(ctx, struct ecryptfs_getdents_callback, ctx);
87 buf->filldir_called++;
88 rc = ecryptfs_decode_and_decrypt_filename(&name, &name_size,
92 printk(KERN_ERR "%s: Error attempting to decode and decrypt "
93 "filename [%s]; rc = [%d]\n", __func__, lower_name,
97 buf->caller->pos = buf->ctx.pos;
98 rc = !dir_emit(buf->caller, name, name_size, ino, d_type);
101 buf->entries_written++;
108 * @file: The eCryptfs directory file
109 * @ctx: The actor to feed the entries to
111 static int ecryptfs_readdir(struct file *file, struct dir_context *ctx)
114 struct file *lower_file;
115 struct inode *inode = file_inode(file);
116 struct ecryptfs_getdents_callback buf = {
117 .ctx.actor = ecryptfs_filldir,
121 lower_file = ecryptfs_file_to_lower(file);
122 lower_file->f_pos = ctx->pos;
123 rc = iterate_dir(lower_file, &buf.ctx);
124 ctx->pos = buf.ctx.pos;
127 if (buf.filldir_called && !buf.entries_written)
130 fsstack_copy_attr_atime(inode,
131 file_inode(lower_file));
136 struct kmem_cache *ecryptfs_file_info_cache;
138 static int read_or_initialize_metadata(struct dentry *dentry)
140 struct inode *inode = dentry->d_inode;
141 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
142 struct ecryptfs_crypt_stat *crypt_stat;
145 crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
146 mount_crypt_stat = &ecryptfs_superblock_to_private(
147 inode->i_sb)->mount_crypt_stat;
148 mutex_lock(&crypt_stat->cs_mutex);
150 if (crypt_stat->flags & ECRYPTFS_POLICY_APPLIED &&
151 crypt_stat->flags & ECRYPTFS_KEY_VALID) {
156 rc = ecryptfs_read_metadata(dentry);
160 if (mount_crypt_stat->flags & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED) {
161 crypt_stat->flags &= ~(ECRYPTFS_I_SIZE_INITIALIZED
162 | ECRYPTFS_ENCRYPTED);
167 if (!(mount_crypt_stat->flags & ECRYPTFS_XATTR_METADATA_ENABLED) &&
168 !i_size_read(ecryptfs_inode_to_lower(inode))) {
169 rc = ecryptfs_initialize_file(dentry, inode);
176 mutex_unlock(&crypt_stat->cs_mutex);
182 * @inode: inode speciying file to open
183 * @file: Structure to return filled in
185 * Opens the file specified by inode.
187 * Returns zero on success; non-zero otherwise
189 static int ecryptfs_open(struct inode *inode, struct file *file)
192 struct ecryptfs_crypt_stat *crypt_stat = NULL;
193 struct dentry *ecryptfs_dentry = file->f_path.dentry;
194 /* Private value of ecryptfs_dentry allocated in
195 * ecryptfs_lookup() */
196 struct ecryptfs_file_info *file_info;
198 /* Released in ecryptfs_release or end of function if failure */
199 file_info = kmem_cache_zalloc(ecryptfs_file_info_cache, GFP_KERNEL);
200 ecryptfs_set_file_private(file, file_info);
202 ecryptfs_printk(KERN_ERR,
203 "Error attempting to allocate memory\n");
207 crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
208 mutex_lock(&crypt_stat->cs_mutex);
209 if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)) {
210 ecryptfs_printk(KERN_DEBUG, "Setting flags for stat...\n");
211 /* Policy code enabled in future release */
212 crypt_stat->flags |= (ECRYPTFS_POLICY_APPLIED
213 | ECRYPTFS_ENCRYPTED);
215 mutex_unlock(&crypt_stat->cs_mutex);
216 rc = ecryptfs_get_lower_file(ecryptfs_dentry, inode);
218 printk(KERN_ERR "%s: Error attempting to initialize "
219 "the lower file for the dentry with name "
220 "[%pd]; rc = [%d]\n", __func__,
221 ecryptfs_dentry, rc);
224 if ((ecryptfs_inode_to_private(inode)->lower_file->f_flags & O_ACCMODE)
225 == O_RDONLY && (file->f_flags & O_ACCMODE) != O_RDONLY) {
227 printk(KERN_WARNING "%s: Lower file is RO; eCryptfs "
228 "file must hence be opened RO\n", __func__);
231 ecryptfs_set_file_lower(
232 file, ecryptfs_inode_to_private(inode)->lower_file);
233 if (d_is_dir(ecryptfs_dentry)) {
234 ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
235 mutex_lock(&crypt_stat->cs_mutex);
236 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
237 mutex_unlock(&crypt_stat->cs_mutex);
241 rc = read_or_initialize_metadata(ecryptfs_dentry);
244 ecryptfs_printk(KERN_DEBUG, "inode w/ addr = [0x%p], i_ino = "
245 "[0x%.16lx] size: [0x%.16llx]\n", inode, inode->i_ino,
246 (unsigned long long)i_size_read(inode));
249 ecryptfs_put_lower_file(inode);
251 kmem_cache_free(ecryptfs_file_info_cache,
252 ecryptfs_file_to_private(file));
257 static int ecryptfs_flush(struct file *file, fl_owner_t td)
259 struct file *lower_file = ecryptfs_file_to_lower(file);
261 if (lower_file->f_op->flush) {
262 filemap_write_and_wait(file->f_mapping);
263 return lower_file->f_op->flush(lower_file, td);
269 static int ecryptfs_release(struct inode *inode, struct file *file)
271 ecryptfs_put_lower_file(inode);
272 kmem_cache_free(ecryptfs_file_info_cache,
273 ecryptfs_file_to_private(file));
278 ecryptfs_fsync(struct file *file, loff_t start, loff_t end, int datasync)
282 rc = filemap_write_and_wait(file->f_mapping);
286 return vfs_fsync(ecryptfs_file_to_lower(file), datasync);
289 static int ecryptfs_fasync(int fd, struct file *file, int flag)
292 struct file *lower_file = NULL;
294 lower_file = ecryptfs_file_to_lower(file);
295 if (lower_file->f_op->fasync)
296 rc = lower_file->f_op->fasync(fd, lower_file, flag);
301 ecryptfs_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
303 struct file *lower_file = ecryptfs_file_to_lower(file);
306 if (lower_file->f_op->unlocked_ioctl)
307 rc = lower_file->f_op->unlocked_ioctl(lower_file, cmd, arg);
313 ecryptfs_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
315 struct file *lower_file = ecryptfs_file_to_lower(file);
316 long rc = -ENOIOCTLCMD;
318 if (lower_file->f_op->compat_ioctl)
319 rc = lower_file->f_op->compat_ioctl(lower_file, cmd, arg);
324 const struct file_operations ecryptfs_dir_fops = {
325 .iterate = ecryptfs_readdir,
326 .read = generic_read_dir,
327 .unlocked_ioctl = ecryptfs_unlocked_ioctl,
329 .compat_ioctl = ecryptfs_compat_ioctl,
331 .open = ecryptfs_open,
332 .flush = ecryptfs_flush,
333 .release = ecryptfs_release,
334 .fsync = ecryptfs_fsync,
335 .fasync = ecryptfs_fasync,
336 .splice_read = generic_file_splice_read,
337 .llseek = default_llseek,
340 const struct file_operations ecryptfs_main_fops = {
341 .llseek = generic_file_llseek,
342 .read = new_sync_read,
343 .read_iter = ecryptfs_read_update_atime,
344 .write = new_sync_write,
345 .write_iter = generic_file_write_iter,
346 .iterate = ecryptfs_readdir,
347 .unlocked_ioctl = ecryptfs_unlocked_ioctl,
349 .compat_ioctl = ecryptfs_compat_ioctl,
351 .mmap = generic_file_mmap,
352 .open = ecryptfs_open,
353 .flush = ecryptfs_flush,
354 .release = ecryptfs_release,
355 .fsync = ecryptfs_fsync,
356 .fasync = ecryptfs_fasync,
357 .splice_read = generic_file_splice_read,