blob: e7440a6f5ebf0cffb9e9bee7a770b80553e72b15 [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>
Jonathan Corbetdda64452008-06-19 16:18:25 -060034#include <linux/smp_lock.h>
Michael Halcrow237fead2006-10-04 02:16:22 -070035#include "ecryptfs_kernel.h"
36
37/**
Michael Halcrow237fead2006-10-04 02:16:22 -070038 * ecryptfs_read_update_atime
39 *
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.
46 */
47static ssize_t ecryptfs_read_update_atime(struct kiocb *iocb,
48 const struct iovec *iov,
49 unsigned long nr_segs, loff_t pos)
50{
51 int rc;
52 struct dentry *lower_dentry;
53 struct vfsmount *lower_vfsmount;
54 struct file *file = iocb->ki_filp;
55
56 rc = generic_file_aio_read(iocb, iov, nr_segs, pos);
57 /*
58 * Even though this is a async interface, we need to wait
59 * for IO to finish to update atime
60 */
61 if (-EIOCBQUEUED == rc)
62 rc = wait_on_sync_kiocb(iocb);
63 if (rc >= 0) {
Josef "Jeff" Sipekbd243a42006-12-08 02:36:48 -080064 lower_dentry = ecryptfs_dentry_to_lower(file->f_path.dentry);
65 lower_vfsmount = ecryptfs_dentry_to_lower_mnt(file->f_path.dentry);
Michael Halcrow237fead2006-10-04 02:16:22 -070066 touch_atime(lower_vfsmount, lower_dentry);
67 }
68 return rc;
69}
70
71struct ecryptfs_getdents_callback {
72 void *dirent;
73 struct dentry *dentry;
74 filldir_t filldir;
Michael Halcrow237fead2006-10-04 02:16:22 -070075 int filldir_called;
76 int entries_written;
77};
78
Michael Halcrow7d6c7042008-10-15 22:02:49 -070079/* Inspired by generic filldir in fs/readdir.c */
Michael Halcrow237fead2006-10-04 02:16:22 -070080static int
Michael Halcrowaddd65ad2009-01-06 14:42:00 -080081ecryptfs_filldir(void *dirent, const char *lower_name, int lower_namelen,
82 loff_t offset, u64 ino, unsigned int d_type)
Michael Halcrow237fead2006-10-04 02:16:22 -070083{
Michael Halcrow237fead2006-10-04 02:16:22 -070084 struct ecryptfs_getdents_callback *buf =
85 (struct ecryptfs_getdents_callback *)dirent;
Michael Halcrowa8f12862009-01-06 14:42:03 -080086 size_t name_size;
Michael Halcrowaddd65ad2009-01-06 14:42:00 -080087 char *name;
Michael Halcrow237fead2006-10-04 02:16:22 -070088 int rc;
Michael Halcrow237fead2006-10-04 02:16:22 -070089
Michael Halcrow237fead2006-10-04 02:16:22 -070090 buf->filldir_called++;
Michael Halcrowaddd65ad2009-01-06 14:42:00 -080091 rc = ecryptfs_decode_and_decrypt_filename(&name, &name_size,
92 buf->dentry, lower_name,
93 lower_namelen);
94 if (rc) {
95 printk(KERN_ERR "%s: Error attempting to decode and decrypt "
96 "filename [%s]; rc = [%d]\n", __func__, lower_name,
97 rc);
Michael Halcrow237fead2006-10-04 02:16:22 -070098 goto out;
99 }
Michael Halcrowaddd65ad2009-01-06 14:42:00 -0800100 rc = buf->filldir(buf->dirent, name, name_size, offset, ino, d_type);
101 kfree(name);
Michael Halcrow237fead2006-10-04 02:16:22 -0700102 if (rc >= 0)
103 buf->entries_written++;
104out:
105 return rc;
106}
107
108/**
109 * ecryptfs_readdir
Michael Halcrowaddd65ad2009-01-06 14:42:00 -0800110 * @file: The eCryptfs directory file
111 * @dirent: Directory entry handle
Michael Halcrow237fead2006-10-04 02:16:22 -0700112 * @filldir: The filldir callback function
113 */
114static int ecryptfs_readdir(struct file *file, void *dirent, filldir_t filldir)
115{
116 int rc;
117 struct file *lower_file;
118 struct inode *inode;
119 struct ecryptfs_getdents_callback buf;
120
121 lower_file = ecryptfs_file_to_lower(file);
122 lower_file->f_pos = file->f_pos;
Josef "Jeff" Sipekbd243a42006-12-08 02:36:48 -0800123 inode = file->f_path.dentry->d_inode;
Michael Halcrow237fead2006-10-04 02:16:22 -0700124 memset(&buf, 0, sizeof(buf));
125 buf.dirent = dirent;
Josef "Jeff" Sipekbd243a42006-12-08 02:36:48 -0800126 buf.dentry = file->f_path.dentry;
Michael Halcrow237fead2006-10-04 02:16:22 -0700127 buf.filldir = filldir;
Michael Halcrow237fead2006-10-04 02:16:22 -0700128 buf.filldir_called = 0;
129 buf.entries_written = 0;
Michael Halcrow237fead2006-10-04 02:16:22 -0700130 rc = vfs_readdir(lower_file, ecryptfs_filldir, (void *)&buf);
Michael Halcrow237fead2006-10-04 02:16:22 -0700131 file->f_pos = lower_file->f_pos;
Michael Halcrow7d6c7042008-10-15 22:02:49 -0700132 if (rc < 0)
133 goto out;
134 if (buf.filldir_called && !buf.entries_written)
135 goto out;
Michael Halcrow237fead2006-10-04 02:16:22 -0700136 if (rc >= 0)
Michael Halcrow7d6c7042008-10-15 22:02:49 -0700137 fsstack_copy_attr_atime(inode,
138 lower_file->f_path.dentry->d_inode);
139out:
Michael Halcrow237fead2006-10-04 02:16:22 -0700140 return rc;
141}
142
143struct kmem_cache *ecryptfs_file_info_cache;
144
145/**
146 * ecryptfs_open
147 * @inode: inode speciying file to open
148 * @file: Structure to return filled in
149 *
150 * Opens the file specified by inode.
151 *
152 * Returns zero on success; non-zero otherwise
153 */
154static int ecryptfs_open(struct inode *inode, struct file *file)
155{
156 int rc = 0;
157 struct ecryptfs_crypt_stat *crypt_stat = NULL;
158 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
Josef "Jeff" Sipekbd243a42006-12-08 02:36:48 -0800159 struct dentry *ecryptfs_dentry = file->f_path.dentry;
Michael Halcrow237fead2006-10-04 02:16:22 -0700160 /* Private value of ecryptfs_dentry allocated in
161 * ecryptfs_lookup() */
Julia Lawall4aa25bc2010-01-16 17:00:26 +0100162 struct dentry *lower_dentry;
Michael Halcrow237fead2006-10-04 02:16:22 -0700163 struct ecryptfs_file_info *file_info;
Michael Halcrow237fead2006-10-04 02:16:22 -0700164
Michael Halcrowe77a56d2007-02-12 00:53:47 -0800165 mount_crypt_stat = &ecryptfs_superblock_to_private(
166 ecryptfs_dentry->d_sb)->mount_crypt_stat;
167 if ((mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
168 && ((file->f_flags & O_WRONLY) || (file->f_flags & O_RDWR)
169 || (file->f_flags & O_CREAT) || (file->f_flags & O_TRUNC)
170 || (file->f_flags & O_APPEND))) {
171 printk(KERN_WARNING "Mount has encrypted view enabled; "
172 "files may only be read\n");
173 rc = -EPERM;
174 goto out;
175 }
Michael Halcrow237fead2006-10-04 02:16:22 -0700176 /* Released in ecryptfs_release or end of function if failure */
Robert P. J. Dayc3762222007-02-10 01:45:03 -0800177 file_info = kmem_cache_zalloc(ecryptfs_file_info_cache, GFP_KERNEL);
Michael Halcrow237fead2006-10-04 02:16:22 -0700178 ecryptfs_set_file_private(file, file_info);
179 if (!file_info) {
180 ecryptfs_printk(KERN_ERR,
181 "Error attempting to allocate memory\n");
182 rc = -ENOMEM;
183 goto out;
184 }
Michael Halcrow237fead2006-10-04 02:16:22 -0700185 lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
186 crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
Michael Halcrow237fead2006-10-04 02:16:22 -0700187 mutex_lock(&crypt_stat->cs_mutex);
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800188 if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)) {
Michael Halcrow237fead2006-10-04 02:16:22 -0700189 ecryptfs_printk(KERN_DEBUG, "Setting flags for stat...\n");
190 /* Policy code enabled in future release */
Michael Halcrow2ed92552007-10-16 01:28:10 -0700191 crypt_stat->flags |= (ECRYPTFS_POLICY_APPLIED
192 | ECRYPTFS_ENCRYPTED);
Michael Halcrow237fead2006-10-04 02:16:22 -0700193 }
194 mutex_unlock(&crypt_stat->cs_mutex);
Michael Halcrow72b55ff2008-07-23 21:30:07 -0700195 if (!ecryptfs_inode_to_private(inode)->lower_file) {
Michael Halcrow72b55ff2008-07-23 21:30:07 -0700196 rc = ecryptfs_init_persistent_file(ecryptfs_dentry);
197 if (rc) {
198 printk(KERN_ERR "%s: Error attempting to initialize "
199 "the persistent file for the dentry with name "
200 "[%s]; rc = [%d]\n", __func__,
201 ecryptfs_dentry->d_name.name, rc);
202 goto out;
203 }
204 }
Erez Zadoke27759d2009-12-03 13:35:27 -0500205 if ((ecryptfs_inode_to_private(inode)->lower_file->f_flags & O_RDONLY)
206 && !(file->f_flags & O_RDONLY)) {
207 rc = -EPERM;
208 printk(KERN_WARNING "%s: Lower persistent file is RO; eCryptfs "
209 "file must hence be opened RO\n", __func__);
210 goto out;
211 }
Michael Halcrow2ed92552007-10-16 01:28:10 -0700212 ecryptfs_set_file_lower(
213 file, ecryptfs_inode_to_private(inode)->lower_file);
Michael Halcrow237fead2006-10-04 02:16:22 -0700214 if (S_ISDIR(ecryptfs_dentry->d_inode->i_mode)) {
215 ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
Michael Halcrow2f9b12a2008-04-29 00:59:52 -0700216 mutex_lock(&crypt_stat->cs_mutex);
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800217 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
Michael Halcrow2f9b12a2008-04-29 00:59:52 -0700218 mutex_unlock(&crypt_stat->cs_mutex);
Michael Halcrow237fead2006-10-04 02:16:22 -0700219 rc = 0;
220 goto out;
221 }
222 mutex_lock(&crypt_stat->cs_mutex);
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800223 if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)
224 || !(crypt_stat->flags & ECRYPTFS_KEY_VALID)) {
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -0700225 rc = ecryptfs_read_metadata(ecryptfs_dentry);
Michael Halcrow237fead2006-10-04 02:16:22 -0700226 if (rc) {
227 ecryptfs_printk(KERN_DEBUG,
228 "Valid headers not found\n");
229 if (!(mount_crypt_stat->flags
230 & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) {
231 rc = -EIO;
Michael Halcrow25bd8172008-02-06 01:38:35 -0800232 printk(KERN_WARNING "Either the lower file "
Michael Halcrow237fead2006-10-04 02:16:22 -0700233 "is not in a valid eCryptfs format, "
Michael Halcrow25bd8172008-02-06 01:38:35 -0800234 "or the key could not be retrieved. "
235 "Plaintext passthrough mode is not "
Michael Halcrow237fead2006-10-04 02:16:22 -0700236 "enabled; returning -EIO\n");
237 mutex_unlock(&crypt_stat->cs_mutex);
Michael Halcrow2ed92552007-10-16 01:28:10 -0700238 goto out_free;
Michael Halcrow237fead2006-10-04 02:16:22 -0700239 }
Michael Halcrow237fead2006-10-04 02:16:22 -0700240 rc = 0;
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800241 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
Michael Halcrow237fead2006-10-04 02:16:22 -0700242 mutex_unlock(&crypt_stat->cs_mutex);
243 goto out;
244 }
245 }
246 mutex_unlock(&crypt_stat->cs_mutex);
247 ecryptfs_printk(KERN_DEBUG, "inode w/ addr = [0x%p], i_ino = [0x%.16x] "
248 "size: [0x%.16x]\n", inode, inode->i_ino,
249 i_size_read(inode));
Michael Halcrow237fead2006-10-04 02:16:22 -0700250 goto out;
Michael Halcrow2ed92552007-10-16 01:28:10 -0700251out_free:
Michael Halcrow237fead2006-10-04 02:16:22 -0700252 kmem_cache_free(ecryptfs_file_info_cache,
253 ecryptfs_file_to_private(file));
254out:
255 return rc;
256}
257
258static int ecryptfs_flush(struct file *file, fl_owner_t td)
259{
260 int rc = 0;
261 struct file *lower_file = NULL;
262
263 lower_file = ecryptfs_file_to_lower(file);
264 if (lower_file->f_op && lower_file->f_op->flush)
265 rc = lower_file->f_op->flush(lower_file, td);
266 return rc;
267}
268
269static int ecryptfs_release(struct inode *inode, struct file *file)
270{
Michael Halcrow2ed92552007-10-16 01:28:10 -0700271 kmem_cache_free(ecryptfs_file_info_cache,
272 ecryptfs_file_to_private(file));
273 return 0;
Michael Halcrow237fead2006-10-04 02:16:22 -0700274}
275
276static int
277ecryptfs_fsync(struct file *file, struct dentry *dentry, int datasync)
278{
Christoph Hellwig4c728ef2008-12-22 21:11:15 +0100279 return vfs_fsync(ecryptfs_file_to_lower(file),
280 ecryptfs_dentry_to_lower(dentry),
281 datasync);
Michael Halcrow237fead2006-10-04 02:16:22 -0700282}
283
284static int ecryptfs_fasync(int fd, struct file *file, int flag)
285{
286 int rc = 0;
287 struct file *lower_file = NULL;
288
Jonathan Corbetdda64452008-06-19 16:18:25 -0600289 lock_kernel();
Michael Halcrow237fead2006-10-04 02:16:22 -0700290 lower_file = ecryptfs_file_to_lower(file);
291 if (lower_file->f_op && lower_file->f_op->fasync)
292 rc = lower_file->f_op->fasync(fd, lower_file, flag);
Jonathan Corbetdda64452008-06-19 16:18:25 -0600293 unlock_kernel();
Michael Halcrow237fead2006-10-04 02:16:22 -0700294 return rc;
295}
296
Michael Halcrow237fead2006-10-04 02:16:22 -0700297static int ecryptfs_ioctl(struct inode *inode, struct file *file,
298 unsigned int cmd, unsigned long arg);
299
300const struct file_operations ecryptfs_dir_fops = {
301 .readdir = ecryptfs_readdir,
302 .ioctl = ecryptfs_ioctl,
Michael Halcrow237fead2006-10-04 02:16:22 -0700303 .open = ecryptfs_open,
304 .flush = ecryptfs_flush,
305 .release = ecryptfs_release,
306 .fsync = ecryptfs_fsync,
307 .fasync = ecryptfs_fasync,
Michael Halcrowe9f6a992007-10-16 01:28:04 -0700308 .splice_read = generic_file_splice_read,
Michael Halcrow237fead2006-10-04 02:16:22 -0700309};
310
311const struct file_operations ecryptfs_main_fops = {
Michael Halcrow53a27312007-05-23 13:58:15 -0700312 .llseek = generic_file_llseek,
Michael Halcrow237fead2006-10-04 02:16:22 -0700313 .read = do_sync_read,
314 .aio_read = ecryptfs_read_update_atime,
315 .write = do_sync_write,
316 .aio_write = generic_file_aio_write,
317 .readdir = ecryptfs_readdir,
318 .ioctl = ecryptfs_ioctl,
319 .mmap = generic_file_mmap,
320 .open = ecryptfs_open,
321 .flush = ecryptfs_flush,
322 .release = ecryptfs_release,
323 .fsync = ecryptfs_fsync,
324 .fasync = ecryptfs_fasync,
Michael Halcrowe9f6a992007-10-16 01:28:04 -0700325 .splice_read = generic_file_splice_read,
Michael Halcrow237fead2006-10-04 02:16:22 -0700326};
327
328static int
329ecryptfs_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
330 unsigned long arg)
331{
332 int rc = 0;
333 struct file *lower_file = NULL;
334
335 if (ecryptfs_file_to_private(file))
336 lower_file = ecryptfs_file_to_lower(file);
337 if (lower_file && lower_file->f_op && lower_file->f_op->ioctl)
338 rc = lower_file->f_op->ioctl(ecryptfs_inode_to_lower(inode),
339 lower_file, cmd, arg);
340 else
341 rc = -ENOTTY;
342 return rc;
343}