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(void *dirent, const char *lower_name, int lower_namelen,
79 loff_t offset, u64 ino, unsigned int d_type)
81 struct ecryptfs_getdents_callback *buf =
82 (struct ecryptfs_getdents_callback *)dirent;
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);
180 static int ecryptfs_mmap(struct file *file, struct vm_area_struct *vma)
182 struct file *lower_file = ecryptfs_file_to_lower(file);
184 * Don't allow mmap on top of file systems that don't support it
185 * natively. If FILESYSTEM_MAX_STACK_DEPTH > 2 or ecryptfs
186 * allows recursive mounting, this will need to be extended.
188 if (!lower_file->f_op->mmap)
190 return generic_file_mmap(file, vma);
195 * @inode: inode speciying file to open
196 * @file: Structure to return filled in
198 * Opens the file specified by inode.
200 * Returns zero on success; non-zero otherwise
202 static int ecryptfs_open(struct inode *inode, struct file *file)
205 struct ecryptfs_crypt_stat *crypt_stat = NULL;
206 struct dentry *ecryptfs_dentry = file->f_path.dentry;
207 /* Private value of ecryptfs_dentry allocated in
208 * ecryptfs_lookup() */
209 struct ecryptfs_file_info *file_info;
211 /* Released in ecryptfs_release or end of function if failure */
212 file_info = kmem_cache_zalloc(ecryptfs_file_info_cache, GFP_KERNEL);
213 ecryptfs_set_file_private(file, file_info);
215 ecryptfs_printk(KERN_ERR,
216 "Error attempting to allocate memory\n");
220 crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
221 mutex_lock(&crypt_stat->cs_mutex);
222 if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)) {
223 ecryptfs_printk(KERN_DEBUG, "Setting flags for stat...\n");
224 /* Policy code enabled in future release */
225 crypt_stat->flags |= (ECRYPTFS_POLICY_APPLIED
226 | ECRYPTFS_ENCRYPTED);
228 mutex_unlock(&crypt_stat->cs_mutex);
229 rc = ecryptfs_get_lower_file(ecryptfs_dentry, inode);
231 printk(KERN_ERR "%s: Error attempting to initialize "
232 "the lower file for the dentry with name "
233 "[%s]; rc = [%d]\n", __func__,
234 ecryptfs_dentry->d_name.name, rc);
237 if ((ecryptfs_inode_to_private(inode)->lower_file->f_flags & O_ACCMODE)
238 == O_RDONLY && (file->f_flags & O_ACCMODE) != O_RDONLY) {
240 printk(KERN_WARNING "%s: Lower file is RO; eCryptfs "
241 "file must hence be opened RO\n", __func__);
244 ecryptfs_set_file_lower(
245 file, ecryptfs_inode_to_private(inode)->lower_file);
246 if (S_ISDIR(ecryptfs_dentry->d_inode->i_mode)) {
247 ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
248 mutex_lock(&crypt_stat->cs_mutex);
249 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
250 mutex_unlock(&crypt_stat->cs_mutex);
254 rc = read_or_initialize_metadata(ecryptfs_dentry);
257 ecryptfs_printk(KERN_DEBUG, "inode w/ addr = [0x%p], i_ino = "
258 "[0x%.16lx] size: [0x%.16llx]\n", inode, inode->i_ino,
259 (unsigned long long)i_size_read(inode));
262 ecryptfs_put_lower_file(inode);
264 kmem_cache_free(ecryptfs_file_info_cache,
265 ecryptfs_file_to_private(file));
270 static int ecryptfs_flush(struct file *file, fl_owner_t td)
272 struct file *lower_file = ecryptfs_file_to_lower(file);
274 if (lower_file->f_op->flush) {
275 filemap_write_and_wait(file->f_mapping);
276 return lower_file->f_op->flush(lower_file, td);
282 static int ecryptfs_release(struct inode *inode, struct file *file)
284 ecryptfs_put_lower_file(inode);
285 kmem_cache_free(ecryptfs_file_info_cache,
286 ecryptfs_file_to_private(file));
291 ecryptfs_fsync(struct file *file, loff_t start, loff_t end, int datasync)
295 rc = filemap_write_and_wait(file->f_mapping);
299 return vfs_fsync(ecryptfs_file_to_lower(file), datasync);
302 static int ecryptfs_fasync(int fd, struct file *file, int flag)
305 struct file *lower_file = NULL;
307 lower_file = ecryptfs_file_to_lower(file);
308 if (lower_file->f_op->fasync)
309 rc = lower_file->f_op->fasync(fd, lower_file, flag);
314 ecryptfs_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
316 struct file *lower_file = ecryptfs_file_to_lower(file);
319 if (!lower_file->f_op->unlocked_ioctl)
324 case FS_IOC_GETFLAGS:
325 case FS_IOC_SETFLAGS:
326 case FS_IOC_GETVERSION:
327 case FS_IOC_SETVERSION:
328 rc = lower_file->f_op->unlocked_ioctl(lower_file, cmd, arg);
329 fsstack_copy_attr_all(file_inode(file), file_inode(lower_file));
339 ecryptfs_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
341 struct file *lower_file = ecryptfs_file_to_lower(file);
342 long rc = -ENOIOCTLCMD;
344 if (!lower_file->f_op->compat_ioctl)
349 case FS_IOC32_GETFLAGS:
350 case FS_IOC32_SETFLAGS:
351 case FS_IOC32_GETVERSION:
352 case FS_IOC32_SETVERSION:
353 rc = lower_file->f_op->compat_ioctl(lower_file, cmd, arg);
354 fsstack_copy_attr_all(file_inode(file), file_inode(lower_file));
363 const struct file_operations ecryptfs_dir_fops = {
364 .iterate = ecryptfs_readdir,
365 .read = generic_read_dir,
366 .unlocked_ioctl = ecryptfs_unlocked_ioctl,
368 .compat_ioctl = ecryptfs_compat_ioctl,
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,
376 .llseek = default_llseek,
379 const struct file_operations ecryptfs_main_fops = {
380 .llseek = generic_file_llseek,
381 .read = new_sync_read,
382 .read_iter = ecryptfs_read_update_atime,
383 .write = new_sync_write,
384 .write_iter = generic_file_write_iter,
385 .iterate = ecryptfs_readdir,
386 .unlocked_ioctl = ecryptfs_unlocked_ioctl,
388 .compat_ioctl = ecryptfs_compat_ioctl,
390 .mmap = ecryptfs_mmap,
391 .open = ecryptfs_open,
392 .flush = ecryptfs_flush,
393 .release = ecryptfs_release,
394 .fsync = ecryptfs_fsync,
395 .fasync = ecryptfs_fasync,
396 .splice_read = generic_file_splice_read,