blob: 53acc9d0c1384ff8030a17e922a7e6fb45dcf081 [file] [log] [blame]
Michael Halcrow237fead2006-10-04 02:16:22 -07001/**
2 * eCryptfs: Linux filesystem encryption layer
3 *
4 * Copyright (C) 1997-2004 Erez Zadok
5 * Copyright (C) 2001-2004 Stony Brook University
Michael Halcrowdd2a3b72007-02-12 00:53:46 -08006 * Copyright (C) 2004-2007 International Business Machines Corp.
Michael Halcrow237fead2006-10-04 02:16:22 -07007 * Author(s): Michael A. Halcrow <mhalcrow@us.ibm.com>
8 * Michael C. Thompson <mcthomps@us.ibm.com>
9 *
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.
14 *
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.
19 *
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
23 * 02111-1307, USA.
24 */
25
26#include <linux/file.h>
27#include <linux/poll.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090028#include <linux/slab.h>
Michael Halcrow237fead2006-10-04 02:16:22 -070029#include <linux/mount.h>
30#include <linux/pagemap.h>
31#include <linux/security.h>
Michael Halcrow237fead2006-10-04 02:16:22 -070032#include <linux/compat.h>
Josef "Jeff" Sipek0cc72dc2006-12-08 02:36:31 -080033#include <linux/fs_stack.h>
Michael Halcrow237fead2006-10-04 02:16:22 -070034#include "ecryptfs_kernel.h"
35
36/**
Michael Halcrow237fead2006-10-04 02:16:22 -070037 * ecryptfs_read_update_atime
38 *
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.
45 */
46static ssize_t ecryptfs_read_update_atime(struct kiocb *iocb,
47 const struct iovec *iov,
48 unsigned long nr_segs, loff_t pos)
49{
Edward Shishkin38a708d2010-10-30 00:11:50 +020050 ssize_t rc;
Al Viro68ac1232012-03-15 08:21:57 -040051 struct path lower;
Michael Halcrow237fead2006-10-04 02:16:22 -070052 struct file *file = iocb->ki_filp;
53
54 rc = generic_file_aio_read(iocb, iov, nr_segs, pos);
55 /*
56 * Even though this is a async interface, we need to wait
57 * for IO to finish to update atime
58 */
59 if (-EIOCBQUEUED == rc)
60 rc = wait_on_sync_kiocb(iocb);
61 if (rc >= 0) {
Al Viro68ac1232012-03-15 08:21:57 -040062 lower.dentry = ecryptfs_dentry_to_lower(file->f_path.dentry);
63 lower.mnt = ecryptfs_dentry_to_lower_mnt(file->f_path.dentry);
64 touch_atime(&lower);
Michael Halcrow237fead2006-10-04 02:16:22 -070065 }
66 return rc;
67}
68
69struct ecryptfs_getdents_callback {
70 void *dirent;
71 struct dentry *dentry;
72 filldir_t filldir;
Michael Halcrow237fead2006-10-04 02:16:22 -070073 int filldir_called;
74 int entries_written;
75};
76
Michael Halcrow7d6c7042008-10-15 22:02:49 -070077/* Inspired by generic filldir in fs/readdir.c */
Michael Halcrow237fead2006-10-04 02:16:22 -070078static int
Michael Halcrowaddd65ad2009-01-06 14:42:00 -080079ecryptfs_filldir(void *dirent, const char *lower_name, int lower_namelen,
80 loff_t offset, u64 ino, unsigned int d_type)
Michael Halcrow237fead2006-10-04 02:16:22 -070081{
Michael Halcrow237fead2006-10-04 02:16:22 -070082 struct ecryptfs_getdents_callback *buf =
83 (struct ecryptfs_getdents_callback *)dirent;
Michael Halcrowa8f12862009-01-06 14:42:03 -080084 size_t name_size;
Michael Halcrowaddd65ad2009-01-06 14:42:00 -080085 char *name;
Michael Halcrow237fead2006-10-04 02:16:22 -070086 int rc;
Michael Halcrow237fead2006-10-04 02:16:22 -070087
Michael Halcrow237fead2006-10-04 02:16:22 -070088 buf->filldir_called++;
Michael Halcrowaddd65ad2009-01-06 14:42:00 -080089 rc = ecryptfs_decode_and_decrypt_filename(&name, &name_size,
90 buf->dentry, lower_name,
91 lower_namelen);
92 if (rc) {
93 printk(KERN_ERR "%s: Error attempting to decode and decrypt "
94 "filename [%s]; rc = [%d]\n", __func__, lower_name,
95 rc);
Michael Halcrow237fead2006-10-04 02:16:22 -070096 goto out;
97 }
Michael Halcrowaddd65ad2009-01-06 14:42:00 -080098 rc = buf->filldir(buf->dirent, name, name_size, offset, ino, d_type);
99 kfree(name);
Michael Halcrow237fead2006-10-04 02:16:22 -0700100 if (rc >= 0)
101 buf->entries_written++;
102out:
103 return rc;
104}
105
106/**
107 * ecryptfs_readdir
Michael Halcrowaddd65ad2009-01-06 14:42:00 -0800108 * @file: The eCryptfs directory file
109 * @dirent: Directory entry handle
Michael Halcrow237fead2006-10-04 02:16:22 -0700110 * @filldir: The filldir callback function
111 */
112static int ecryptfs_readdir(struct file *file, void *dirent, filldir_t filldir)
113{
114 int rc;
115 struct file *lower_file;
116 struct inode *inode;
117 struct ecryptfs_getdents_callback buf;
118
119 lower_file = ecryptfs_file_to_lower(file);
120 lower_file->f_pos = file->f_pos;
Al Viro496ad9a2013-01-23 17:07:38 -0500121 inode = file_inode(file);
Michael Halcrow237fead2006-10-04 02:16:22 -0700122 memset(&buf, 0, sizeof(buf));
123 buf.dirent = dirent;
Josef "Jeff" Sipekbd243a42006-12-08 02:36:48 -0800124 buf.dentry = file->f_path.dentry;
Michael Halcrow237fead2006-10-04 02:16:22 -0700125 buf.filldir = filldir;
Michael Halcrow237fead2006-10-04 02:16:22 -0700126 buf.filldir_called = 0;
127 buf.entries_written = 0;
Michael Halcrow237fead2006-10-04 02:16:22 -0700128 rc = vfs_readdir(lower_file, ecryptfs_filldir, (void *)&buf);
Michael Halcrow237fead2006-10-04 02:16:22 -0700129 file->f_pos = lower_file->f_pos;
Michael Halcrow7d6c7042008-10-15 22:02:49 -0700130 if (rc < 0)
131 goto out;
132 if (buf.filldir_called && !buf.entries_written)
133 goto out;
Michael Halcrow237fead2006-10-04 02:16:22 -0700134 if (rc >= 0)
Michael Halcrow7d6c7042008-10-15 22:02:49 -0700135 fsstack_copy_attr_atime(inode,
Al Viro496ad9a2013-01-23 17:07:38 -0500136 file_inode(lower_file));
Michael Halcrow7d6c7042008-10-15 22:02:49 -0700137out:
Michael Halcrow237fead2006-10-04 02:16:22 -0700138 return rc;
139}
140
141struct kmem_cache *ecryptfs_file_info_cache;
142
Tyler Hickse3ccaa92012-06-20 23:50:59 -0700143static int read_or_initialize_metadata(struct dentry *dentry)
144{
145 struct inode *inode = dentry->d_inode;
146 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
147 struct ecryptfs_crypt_stat *crypt_stat;
148 int rc;
149
150 crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
151 mount_crypt_stat = &ecryptfs_superblock_to_private(
152 inode->i_sb)->mount_crypt_stat;
153 mutex_lock(&crypt_stat->cs_mutex);
154
155 if (crypt_stat->flags & ECRYPTFS_POLICY_APPLIED &&
156 crypt_stat->flags & ECRYPTFS_KEY_VALID) {
157 rc = 0;
158 goto out;
159 }
160
161 rc = ecryptfs_read_metadata(dentry);
162 if (!rc)
163 goto out;
164
165 if (mount_crypt_stat->flags & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED) {
166 crypt_stat->flags &= ~(ECRYPTFS_I_SIZE_INITIALIZED
167 | ECRYPTFS_ENCRYPTED);
168 rc = 0;
169 goto out;
170 }
171
172 if (!(mount_crypt_stat->flags & ECRYPTFS_XATTR_METADATA_ENABLED) &&
173 !i_size_read(ecryptfs_inode_to_lower(inode))) {
174 rc = ecryptfs_initialize_file(dentry, inode);
175 if (!rc)
176 goto out;
177 }
178
179 rc = -EIO;
180out:
181 mutex_unlock(&crypt_stat->cs_mutex);
182 return rc;
183}
184
Michael Halcrow237fead2006-10-04 02:16:22 -0700185/**
186 * ecryptfs_open
187 * @inode: inode speciying file to open
188 * @file: Structure to return filled in
189 *
190 * Opens the file specified by inode.
191 *
192 * Returns zero on success; non-zero otherwise
193 */
194static int ecryptfs_open(struct inode *inode, struct file *file)
195{
196 int rc = 0;
197 struct ecryptfs_crypt_stat *crypt_stat = NULL;
198 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
Josef "Jeff" Sipekbd243a42006-12-08 02:36:48 -0800199 struct dentry *ecryptfs_dentry = file->f_path.dentry;
Michael Halcrow237fead2006-10-04 02:16:22 -0700200 /* Private value of ecryptfs_dentry allocated in
201 * ecryptfs_lookup() */
Julia Lawall4aa25bc2010-01-16 17:00:26 +0100202 struct dentry *lower_dentry;
Michael Halcrow237fead2006-10-04 02:16:22 -0700203 struct ecryptfs_file_info *file_info;
Michael Halcrow237fead2006-10-04 02:16:22 -0700204
Michael Halcrowe77a56d2007-02-12 00:53:47 -0800205 mount_crypt_stat = &ecryptfs_superblock_to_private(
206 ecryptfs_dentry->d_sb)->mount_crypt_stat;
207 if ((mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
208 && ((file->f_flags & O_WRONLY) || (file->f_flags & O_RDWR)
209 || (file->f_flags & O_CREAT) || (file->f_flags & O_TRUNC)
210 || (file->f_flags & O_APPEND))) {
211 printk(KERN_WARNING "Mount has encrypted view enabled; "
212 "files may only be read\n");
213 rc = -EPERM;
214 goto out;
215 }
Michael Halcrow237fead2006-10-04 02:16:22 -0700216 /* Released in ecryptfs_release or end of function if failure */
Robert P. J. Dayc3762222007-02-10 01:45:03 -0800217 file_info = kmem_cache_zalloc(ecryptfs_file_info_cache, GFP_KERNEL);
Michael Halcrow237fead2006-10-04 02:16:22 -0700218 ecryptfs_set_file_private(file, file_info);
219 if (!file_info) {
220 ecryptfs_printk(KERN_ERR,
221 "Error attempting to allocate memory\n");
222 rc = -ENOMEM;
223 goto out;
224 }
Michael Halcrow237fead2006-10-04 02:16:22 -0700225 lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
226 crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
Michael Halcrow237fead2006-10-04 02:16:22 -0700227 mutex_lock(&crypt_stat->cs_mutex);
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800228 if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)) {
Michael Halcrow237fead2006-10-04 02:16:22 -0700229 ecryptfs_printk(KERN_DEBUG, "Setting flags for stat...\n");
230 /* Policy code enabled in future release */
Michael Halcrow2ed92552007-10-16 01:28:10 -0700231 crypt_stat->flags |= (ECRYPTFS_POLICY_APPLIED
232 | ECRYPTFS_ENCRYPTED);
Michael Halcrow237fead2006-10-04 02:16:22 -0700233 }
234 mutex_unlock(&crypt_stat->cs_mutex);
Tyler Hicks3b06b3e2011-05-24 03:49:02 -0500235 rc = ecryptfs_get_lower_file(ecryptfs_dentry, inode);
Roberto Sassu27992892010-11-03 11:11:28 +0100236 if (rc) {
237 printk(KERN_ERR "%s: Error attempting to initialize "
Tyler Hicks332ab162011-04-14 15:35:11 -0500238 "the lower file for the dentry with name "
Roberto Sassu27992892010-11-03 11:11:28 +0100239 "[%s]; rc = [%d]\n", __func__,
240 ecryptfs_dentry->d_name.name, rc);
241 goto out_free;
Michael Halcrow72b55ff2008-07-23 21:30:07 -0700242 }
Roberto Sassu0abe1162010-11-03 11:11:34 +0100243 if ((ecryptfs_inode_to_private(inode)->lower_file->f_flags & O_ACCMODE)
244 == O_RDONLY && (file->f_flags & O_ACCMODE) != O_RDONLY) {
Erez Zadoke27759d2009-12-03 13:35:27 -0500245 rc = -EPERM;
Tyler Hicks332ab162011-04-14 15:35:11 -0500246 printk(KERN_WARNING "%s: Lower file is RO; eCryptfs "
Erez Zadoke27759d2009-12-03 13:35:27 -0500247 "file must hence be opened RO\n", __func__);
Tyler Hicks332ab162011-04-14 15:35:11 -0500248 goto out_put;
Erez Zadoke27759d2009-12-03 13:35:27 -0500249 }
Michael Halcrow2ed92552007-10-16 01:28:10 -0700250 ecryptfs_set_file_lower(
251 file, ecryptfs_inode_to_private(inode)->lower_file);
Michael Halcrow237fead2006-10-04 02:16:22 -0700252 if (S_ISDIR(ecryptfs_dentry->d_inode->i_mode)) {
253 ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
Michael Halcrow2f9b12a2008-04-29 00:59:52 -0700254 mutex_lock(&crypt_stat->cs_mutex);
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800255 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
Michael Halcrow2f9b12a2008-04-29 00:59:52 -0700256 mutex_unlock(&crypt_stat->cs_mutex);
Michael Halcrow237fead2006-10-04 02:16:22 -0700257 rc = 0;
258 goto out;
259 }
Tyler Hickse3ccaa92012-06-20 23:50:59 -0700260 rc = read_or_initialize_metadata(ecryptfs_dentry);
261 if (rc)
262 goto out_put;
Joe Perches888d57b2010-11-10 15:46:16 -0800263 ecryptfs_printk(KERN_DEBUG, "inode w/ addr = [0x%p], i_ino = "
264 "[0x%.16lx] size: [0x%.16llx]\n", inode, inode->i_ino,
265 (unsigned long long)i_size_read(inode));
Michael Halcrow237fead2006-10-04 02:16:22 -0700266 goto out;
Tyler Hicks332ab162011-04-14 15:35:11 -0500267out_put:
268 ecryptfs_put_lower_file(inode);
Michael Halcrow2ed92552007-10-16 01:28:10 -0700269out_free:
Michael Halcrow237fead2006-10-04 02:16:22 -0700270 kmem_cache_free(ecryptfs_file_info_cache,
271 ecryptfs_file_to_private(file));
272out:
273 return rc;
274}
275
276static int ecryptfs_flush(struct file *file, fl_owner_t td)
277{
Tyler Hicks64e66512012-09-12 18:38:00 -0700278 struct file *lower_file = ecryptfs_file_to_lower(file);
279
280 if (lower_file->f_op && lower_file->f_op->flush) {
281 filemap_write_and_wait(file->f_mapping);
282 return lower_file->f_op->flush(lower_file, td);
283 }
284
285 return 0;
Michael Halcrow237fead2006-10-04 02:16:22 -0700286}
287
288static int ecryptfs_release(struct inode *inode, struct file *file)
289{
Tyler Hicks332ab162011-04-14 15:35:11 -0500290 ecryptfs_put_lower_file(inode);
Michael Halcrow2ed92552007-10-16 01:28:10 -0700291 kmem_cache_free(ecryptfs_file_info_cache,
292 ecryptfs_file_to_private(file));
293 return 0;
Michael Halcrow237fead2006-10-04 02:16:22 -0700294}
295
296static int
Josef Bacik02c24a82011-07-16 20:44:56 -0400297ecryptfs_fsync(struct file *file, loff_t start, loff_t end, int datasync)
Michael Halcrow237fead2006-10-04 02:16:22 -0700298{
Tyler Hicks821f7492012-07-03 16:50:57 -0700299 return vfs_fsync(ecryptfs_file_to_lower(file), datasync);
Michael Halcrow237fead2006-10-04 02:16:22 -0700300}
301
302static int ecryptfs_fasync(int fd, struct file *file, int flag)
303{
304 int rc = 0;
305 struct file *lower_file = NULL;
306
307 lower_file = ecryptfs_file_to_lower(file);
308 if (lower_file->f_op && lower_file->f_op->fasync)
309 rc = lower_file->f_op->fasync(fd, lower_file, flag);
310 return rc;
311}
312
Tyler Hicksc43f7b82009-11-03 11:45:11 -0600313static long
314ecryptfs_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
315{
316 struct file *lower_file = NULL;
317 long rc = -ENOTTY;
318
319 if (ecryptfs_file_to_private(file))
320 lower_file = ecryptfs_file_to_lower(file);
321 if (lower_file && lower_file->f_op && lower_file->f_op->unlocked_ioctl)
322 rc = lower_file->f_op->unlocked_ioctl(lower_file, cmd, arg);
323 return rc;
324}
325
326#ifdef CONFIG_COMPAT
327static long
328ecryptfs_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
329{
330 struct file *lower_file = NULL;
331 long rc = -ENOIOCTLCMD;
332
333 if (ecryptfs_file_to_private(file))
334 lower_file = ecryptfs_file_to_lower(file);
335 if (lower_file && lower_file->f_op && lower_file->f_op->compat_ioctl)
336 rc = lower_file->f_op->compat_ioctl(lower_file, cmd, arg);
337 return rc;
338}
339#endif
Michael Halcrow237fead2006-10-04 02:16:22 -0700340
341const struct file_operations ecryptfs_dir_fops = {
342 .readdir = ecryptfs_readdir,
Andy Whitcroft323ef682011-02-16 04:49:59 +0000343 .read = generic_read_dir,
Tyler Hicksc43f7b82009-11-03 11:45:11 -0600344 .unlocked_ioctl = ecryptfs_unlocked_ioctl,
345#ifdef CONFIG_COMPAT
346 .compat_ioctl = ecryptfs_compat_ioctl,
347#endif
Michael Halcrow237fead2006-10-04 02:16:22 -0700348 .open = ecryptfs_open,
349 .flush = ecryptfs_flush,
350 .release = ecryptfs_release,
351 .fsync = ecryptfs_fsync,
352 .fasync = ecryptfs_fasync,
Michael Halcrowe9f6a992007-10-16 01:28:04 -0700353 .splice_read = generic_file_splice_read,
Arnd Bergmann6038f372010-08-15 18:52:59 +0200354 .llseek = default_llseek,
Michael Halcrow237fead2006-10-04 02:16:22 -0700355};
356
357const struct file_operations ecryptfs_main_fops = {
Michael Halcrow53a27312007-05-23 13:58:15 -0700358 .llseek = generic_file_llseek,
Michael Halcrow237fead2006-10-04 02:16:22 -0700359 .read = do_sync_read,
360 .aio_read = ecryptfs_read_update_atime,
361 .write = do_sync_write,
362 .aio_write = generic_file_aio_write,
363 .readdir = ecryptfs_readdir,
Tyler Hicksc43f7b82009-11-03 11:45:11 -0600364 .unlocked_ioctl = ecryptfs_unlocked_ioctl,
365#ifdef CONFIG_COMPAT
366 .compat_ioctl = ecryptfs_compat_ioctl,
367#endif
Tyler Hicks821f7492012-07-03 16:50:57 -0700368 .mmap = generic_file_mmap,
Michael Halcrow237fead2006-10-04 02:16:22 -0700369 .open = ecryptfs_open,
370 .flush = ecryptfs_flush,
371 .release = ecryptfs_release,
372 .fsync = ecryptfs_fsync,
373 .fasync = ecryptfs_fasync,
Michael Halcrowe9f6a992007-10-16 01:28:04 -0700374 .splice_read = generic_file_splice_read,
Michael Halcrow237fead2006-10-04 02:16:22 -0700375};