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,
51 struct file *file = iocb->ki_filp;
53 rc = generic_file_read_iter(iocb, to);
55 path = ecryptfs_dentry_to_lower_path(file->f_path.dentry);
61 struct ecryptfs_getdents_callback {
62 struct dir_context ctx;
63 struct dir_context *caller;
64 struct super_block *sb;
69 /* Inspired by generic filldir in fs/readdir.c */
71 ecryptfs_filldir(struct dir_context *ctx, const char *lower_name,
72 int lower_namelen, loff_t offset, u64 ino, unsigned int d_type)
74 struct ecryptfs_getdents_callback *buf =
75 container_of(ctx, struct ecryptfs_getdents_callback, ctx);
80 buf->filldir_called++;
81 rc = ecryptfs_decode_and_decrypt_filename(&name, &name_size,
85 printk(KERN_ERR "%s: Error attempting to decode and decrypt "
86 "filename [%s]; rc = [%d]\n", __func__, lower_name,
90 buf->caller->pos = buf->ctx.pos;
91 rc = !dir_emit(buf->caller, name, name_size, ino, d_type);
94 buf->entries_written++;
101 * @file: The eCryptfs directory file
102 * @ctx: The actor to feed the entries to
104 static int ecryptfs_readdir(struct file *file, struct dir_context *ctx)
107 struct file *lower_file;
108 struct inode *inode = file_inode(file);
109 struct ecryptfs_getdents_callback buf = {
110 .ctx.actor = ecryptfs_filldir,
114 lower_file = ecryptfs_file_to_lower(file);
115 lower_file->f_pos = ctx->pos;
116 rc = iterate_dir(lower_file, &buf.ctx);
117 ctx->pos = buf.ctx.pos;
120 if (buf.filldir_called && !buf.entries_written)
123 fsstack_copy_attr_atime(inode,
124 file_inode(lower_file));
129 struct kmem_cache *ecryptfs_file_info_cache;
131 static int read_or_initialize_metadata(struct dentry *dentry)
133 struct inode *inode = d_inode(dentry);
134 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
135 struct ecryptfs_crypt_stat *crypt_stat;
138 crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
139 mount_crypt_stat = &ecryptfs_superblock_to_private(
140 inode->i_sb)->mount_crypt_stat;
141 mutex_lock(&crypt_stat->cs_mutex);
143 if (crypt_stat->flags & ECRYPTFS_POLICY_APPLIED &&
144 crypt_stat->flags & ECRYPTFS_KEY_VALID) {
149 rc = ecryptfs_read_metadata(dentry);
153 if (mount_crypt_stat->flags & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED) {
154 crypt_stat->flags &= ~(ECRYPTFS_I_SIZE_INITIALIZED
155 | ECRYPTFS_ENCRYPTED);
160 if (!(mount_crypt_stat->flags & ECRYPTFS_XATTR_METADATA_ENABLED) &&
161 !i_size_read(ecryptfs_inode_to_lower(inode))) {
162 rc = ecryptfs_initialize_file(dentry, inode);
169 mutex_unlock(&crypt_stat->cs_mutex);
173 static int ecryptfs_mmap(struct file *file, struct vm_area_struct *vma)
175 struct file *lower_file = ecryptfs_file_to_lower(file);
177 * Don't allow mmap on top of file systems that don't support it
178 * natively. If FILESYSTEM_MAX_STACK_DEPTH > 2 or ecryptfs
179 * allows recursive mounting, this will need to be extended.
181 if (!lower_file->f_op->mmap)
183 return generic_file_mmap(file, vma);
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 "[%pd]; rc = [%d]\n", __func__,
227 ecryptfs_dentry, 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 (d_is_dir(ecryptfs_dentry)) {
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->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->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 = ecryptfs_file_to_lower(file);
312 if (!lower_file->f_op->unlocked_ioctl)
317 case FS_IOC_GETFLAGS:
318 case FS_IOC_SETFLAGS:
319 case FS_IOC_GETVERSION:
320 case FS_IOC_SETVERSION:
321 rc = lower_file->f_op->unlocked_ioctl(lower_file, cmd, arg);
322 fsstack_copy_attr_all(file_inode(file), file_inode(lower_file));
332 ecryptfs_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
334 struct file *lower_file = ecryptfs_file_to_lower(file);
335 long rc = -ENOIOCTLCMD;
337 if (!lower_file->f_op->compat_ioctl)
341 case FS_IOC32_GETFLAGS:
342 case FS_IOC32_SETFLAGS:
343 case FS_IOC32_GETVERSION:
344 case FS_IOC32_SETVERSION:
345 rc = lower_file->f_op->compat_ioctl(lower_file, cmd, arg);
346 fsstack_copy_attr_all(file_inode(file), file_inode(lower_file));
355 const struct file_operations ecryptfs_dir_fops = {
356 .iterate = ecryptfs_readdir,
357 .read = generic_read_dir,
358 .unlocked_ioctl = ecryptfs_unlocked_ioctl,
360 .compat_ioctl = ecryptfs_compat_ioctl,
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,
368 .llseek = default_llseek,
371 const struct file_operations ecryptfs_main_fops = {
372 .llseek = generic_file_llseek,
373 .read_iter = ecryptfs_read_update_atime,
374 .write_iter = generic_file_write_iter,
375 .iterate = ecryptfs_readdir,
376 .unlocked_ioctl = ecryptfs_unlocked_ioctl,
378 .compat_ioctl = ecryptfs_compat_ioctl,
380 .mmap = ecryptfs_mmap,
381 .open = ecryptfs_open,
382 .flush = ecryptfs_flush,
383 .release = ecryptfs_release,
384 .fsync = ecryptfs_fsync,
385 .fasync = ecryptfs_fasync,
386 .splice_read = generic_file_splice_read,