blob: 9e944057001bfb83bc484b2136e628d2282c089f [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>
28#include <linux/mount.h>
29#include <linux/pagemap.h>
30#include <linux/security.h>
Michael Halcrow237fead2006-10-04 02:16:22 -070031#include <linux/compat.h>
Josef "Jeff" Sipek0cc72dc2006-12-08 02:36:31 -080032#include <linux/fs_stack.h>
Jonathan Corbetdda64452008-06-19 16:18:25 -060033#include <linux/smp_lock.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{
50 int rc;
51 struct dentry *lower_dentry;
52 struct vfsmount *lower_vfsmount;
53 struct file *file = iocb->ki_filp;
54
55 rc = generic_file_aio_read(iocb, iov, nr_segs, pos);
56 /*
57 * Even though this is a async interface, we need to wait
58 * for IO to finish to update atime
59 */
60 if (-EIOCBQUEUED == rc)
61 rc = wait_on_sync_kiocb(iocb);
62 if (rc >= 0) {
Josef "Jeff" Sipekbd243a42006-12-08 02:36:48 -080063 lower_dentry = ecryptfs_dentry_to_lower(file->f_path.dentry);
64 lower_vfsmount = ecryptfs_dentry_to_lower_mnt(file->f_path.dentry);
Michael Halcrow237fead2006-10-04 02:16:22 -070065 touch_atime(lower_vfsmount, lower_dentry);
66 }
67 return rc;
68}
69
70struct ecryptfs_getdents_callback {
71 void *dirent;
72 struct dentry *dentry;
73 filldir_t filldir;
Michael Halcrow237fead2006-10-04 02:16:22 -070074 int filldir_called;
75 int entries_written;
76};
77
Michael Halcrow7d6c7042008-10-15 22:02:49 -070078/* Inspired by generic filldir in fs/readdir.c */
Michael Halcrow237fead2006-10-04 02:16:22 -070079static int
Michael Halcrowaddd65ad2009-01-06 14:42:00 -080080ecryptfs_filldir(void *dirent, const char *lower_name, int lower_namelen,
81 loff_t offset, u64 ino, unsigned int d_type)
Michael Halcrow237fead2006-10-04 02:16:22 -070082{
Michael Halcrow237fead2006-10-04 02:16:22 -070083 struct ecryptfs_getdents_callback *buf =
84 (struct ecryptfs_getdents_callback *)dirent;
Michael Halcrowa8f12862009-01-06 14:42:03 -080085 size_t name_size;
Michael Halcrowaddd65ad2009-01-06 14:42:00 -080086 char *name;
Michael Halcrow237fead2006-10-04 02:16:22 -070087 int rc;
Michael Halcrow237fead2006-10-04 02:16:22 -070088
Michael Halcrow237fead2006-10-04 02:16:22 -070089 buf->filldir_called++;
Michael Halcrowaddd65ad2009-01-06 14:42:00 -080090 rc = ecryptfs_decode_and_decrypt_filename(&name, &name_size,
91 buf->dentry, lower_name,
92 lower_namelen);
93 if (rc) {
94 printk(KERN_ERR "%s: Error attempting to decode and decrypt "
95 "filename [%s]; rc = [%d]\n", __func__, lower_name,
96 rc);
Michael Halcrow237fead2006-10-04 02:16:22 -070097 goto out;
98 }
Michael Halcrowaddd65ad2009-01-06 14:42:00 -080099 rc = buf->filldir(buf->dirent, name, name_size, offset, ino, d_type);
100 kfree(name);
Michael Halcrow237fead2006-10-04 02:16:22 -0700101 if (rc >= 0)
102 buf->entries_written++;
103out:
104 return rc;
105}
106
107/**
108 * ecryptfs_readdir
Michael Halcrowaddd65ad2009-01-06 14:42:00 -0800109 * @file: The eCryptfs directory file
110 * @dirent: Directory entry handle
Michael Halcrow237fead2006-10-04 02:16:22 -0700111 * @filldir: The filldir callback function
112 */
113static int ecryptfs_readdir(struct file *file, void *dirent, filldir_t filldir)
114{
115 int rc;
116 struct file *lower_file;
117 struct inode *inode;
118 struct ecryptfs_getdents_callback buf;
119
120 lower_file = ecryptfs_file_to_lower(file);
121 lower_file->f_pos = file->f_pos;
Josef "Jeff" Sipekbd243a42006-12-08 02:36:48 -0800122 inode = file->f_path.dentry->d_inode;
Michael Halcrow237fead2006-10-04 02:16:22 -0700123 memset(&buf, 0, sizeof(buf));
124 buf.dirent = dirent;
Josef "Jeff" Sipekbd243a42006-12-08 02:36:48 -0800125 buf.dentry = file->f_path.dentry;
Michael Halcrow237fead2006-10-04 02:16:22 -0700126 buf.filldir = filldir;
Michael Halcrow237fead2006-10-04 02:16:22 -0700127 buf.filldir_called = 0;
128 buf.entries_written = 0;
Michael Halcrow237fead2006-10-04 02:16:22 -0700129 rc = vfs_readdir(lower_file, ecryptfs_filldir, (void *)&buf);
Michael Halcrow237fead2006-10-04 02:16:22 -0700130 file->f_pos = lower_file->f_pos;
Michael Halcrow7d6c7042008-10-15 22:02:49 -0700131 if (rc < 0)
132 goto out;
133 if (buf.filldir_called && !buf.entries_written)
134 goto out;
Michael Halcrow237fead2006-10-04 02:16:22 -0700135 if (rc >= 0)
Michael Halcrow7d6c7042008-10-15 22:02:49 -0700136 fsstack_copy_attr_atime(inode,
137 lower_file->f_path.dentry->d_inode);
138out:
Michael Halcrow237fead2006-10-04 02:16:22 -0700139 return rc;
140}
141
142struct kmem_cache *ecryptfs_file_info_cache;
143
144/**
145 * ecryptfs_open
146 * @inode: inode speciying file to open
147 * @file: Structure to return filled in
148 *
149 * Opens the file specified by inode.
150 *
151 * Returns zero on success; non-zero otherwise
152 */
153static int ecryptfs_open(struct inode *inode, struct file *file)
154{
155 int rc = 0;
156 struct ecryptfs_crypt_stat *crypt_stat = NULL;
157 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
Josef "Jeff" Sipekbd243a42006-12-08 02:36:48 -0800158 struct dentry *ecryptfs_dentry = file->f_path.dentry;
Michael Halcrow237fead2006-10-04 02:16:22 -0700159 /* Private value of ecryptfs_dentry allocated in
160 * ecryptfs_lookup() */
161 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
Michael Halcrow237fead2006-10-04 02:16:22 -0700162 struct ecryptfs_file_info *file_info;
Michael Halcrow237fead2006-10-04 02:16:22 -0700163
Michael Halcrowe77a56d2007-02-12 00:53:47 -0800164 mount_crypt_stat = &ecryptfs_superblock_to_private(
165 ecryptfs_dentry->d_sb)->mount_crypt_stat;
166 if ((mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
167 && ((file->f_flags & O_WRONLY) || (file->f_flags & O_RDWR)
168 || (file->f_flags & O_CREAT) || (file->f_flags & O_TRUNC)
169 || (file->f_flags & O_APPEND))) {
170 printk(KERN_WARNING "Mount has encrypted view enabled; "
171 "files may only be read\n");
172 rc = -EPERM;
173 goto out;
174 }
Michael Halcrow237fead2006-10-04 02:16:22 -0700175 /* Released in ecryptfs_release or end of function if failure */
Robert P. J. Dayc3762222007-02-10 01:45:03 -0800176 file_info = kmem_cache_zalloc(ecryptfs_file_info_cache, GFP_KERNEL);
Michael Halcrow237fead2006-10-04 02:16:22 -0700177 ecryptfs_set_file_private(file, file_info);
178 if (!file_info) {
179 ecryptfs_printk(KERN_ERR,
180 "Error attempting to allocate memory\n");
181 rc = -ENOMEM;
182 goto out;
183 }
Michael Halcrow237fead2006-10-04 02:16:22 -0700184 lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
185 crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
Michael Halcrow237fead2006-10-04 02:16:22 -0700186 mutex_lock(&crypt_stat->cs_mutex);
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800187 if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)) {
Michael Halcrow237fead2006-10-04 02:16:22 -0700188 ecryptfs_printk(KERN_DEBUG, "Setting flags for stat...\n");
189 /* Policy code enabled in future release */
Michael Halcrow2ed92552007-10-16 01:28:10 -0700190 crypt_stat->flags |= (ECRYPTFS_POLICY_APPLIED
191 | ECRYPTFS_ENCRYPTED);
Michael Halcrow237fead2006-10-04 02:16:22 -0700192 }
193 mutex_unlock(&crypt_stat->cs_mutex);
Michael Halcrow746f1e52008-07-23 21:30:02 -0700194 if ((ecryptfs_inode_to_private(inode)->lower_file->f_flags & O_RDONLY)
195 && !(file->f_flags & O_RDONLY)) {
196 rc = -EPERM;
197 printk(KERN_WARNING "%s: Lower persistent file is RO; eCryptfs "
198 "file must hence be opened RO\n", __func__);
199 goto out;
200 }
Michael Halcrow72b55ff2008-07-23 21:30:07 -0700201 if (!ecryptfs_inode_to_private(inode)->lower_file) {
Michael Halcrow72b55ff2008-07-23 21:30:07 -0700202 rc = ecryptfs_init_persistent_file(ecryptfs_dentry);
203 if (rc) {
204 printk(KERN_ERR "%s: Error attempting to initialize "
205 "the persistent file for the dentry with name "
206 "[%s]; rc = [%d]\n", __func__,
207 ecryptfs_dentry->d_name.name, rc);
208 goto out;
209 }
210 }
Michael Halcrow2ed92552007-10-16 01:28:10 -0700211 ecryptfs_set_file_lower(
212 file, ecryptfs_inode_to_private(inode)->lower_file);
Michael Halcrow237fead2006-10-04 02:16:22 -0700213 if (S_ISDIR(ecryptfs_dentry->d_inode->i_mode)) {
214 ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
Michael Halcrow2f9b12a2008-04-29 00:59:52 -0700215 mutex_lock(&crypt_stat->cs_mutex);
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800216 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
Michael Halcrow2f9b12a2008-04-29 00:59:52 -0700217 mutex_unlock(&crypt_stat->cs_mutex);
Michael Halcrow237fead2006-10-04 02:16:22 -0700218 rc = 0;
219 goto out;
220 }
221 mutex_lock(&crypt_stat->cs_mutex);
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800222 if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)
223 || !(crypt_stat->flags & ECRYPTFS_KEY_VALID)) {
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -0700224 rc = ecryptfs_read_metadata(ecryptfs_dentry);
Michael Halcrow237fead2006-10-04 02:16:22 -0700225 if (rc) {
226 ecryptfs_printk(KERN_DEBUG,
227 "Valid headers not found\n");
228 if (!(mount_crypt_stat->flags
229 & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) {
230 rc = -EIO;
Michael Halcrow25bd8172008-02-06 01:38:35 -0800231 printk(KERN_WARNING "Either the lower file "
Michael Halcrow237fead2006-10-04 02:16:22 -0700232 "is not in a valid eCryptfs format, "
Michael Halcrow25bd8172008-02-06 01:38:35 -0800233 "or the key could not be retrieved. "
234 "Plaintext passthrough mode is not "
Michael Halcrow237fead2006-10-04 02:16:22 -0700235 "enabled; returning -EIO\n");
236 mutex_unlock(&crypt_stat->cs_mutex);
Michael Halcrow2ed92552007-10-16 01:28:10 -0700237 goto out_free;
Michael Halcrow237fead2006-10-04 02:16:22 -0700238 }
Michael Halcrow237fead2006-10-04 02:16:22 -0700239 rc = 0;
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800240 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
Michael Halcrow237fead2006-10-04 02:16:22 -0700241 mutex_unlock(&crypt_stat->cs_mutex);
242 goto out;
243 }
244 }
245 mutex_unlock(&crypt_stat->cs_mutex);
246 ecryptfs_printk(KERN_DEBUG, "inode w/ addr = [0x%p], i_ino = [0x%.16x] "
247 "size: [0x%.16x]\n", inode, inode->i_ino,
248 i_size_read(inode));
Michael Halcrow237fead2006-10-04 02:16:22 -0700249 goto out;
Michael Halcrow2ed92552007-10-16 01:28:10 -0700250out_free:
Michael Halcrow237fead2006-10-04 02:16:22 -0700251 kmem_cache_free(ecryptfs_file_info_cache,
252 ecryptfs_file_to_private(file));
253out:
254 return rc;
255}
256
257static int ecryptfs_flush(struct file *file, fl_owner_t td)
258{
259 int rc = 0;
260 struct file *lower_file = NULL;
261
262 lower_file = ecryptfs_file_to_lower(file);
263 if (lower_file->f_op && lower_file->f_op->flush)
264 rc = lower_file->f_op->flush(lower_file, td);
265 return rc;
266}
267
268static int ecryptfs_release(struct inode *inode, struct file *file)
269{
Michael Halcrow2ed92552007-10-16 01:28:10 -0700270 kmem_cache_free(ecryptfs_file_info_cache,
271 ecryptfs_file_to_private(file));
272 return 0;
Michael Halcrow237fead2006-10-04 02:16:22 -0700273}
274
275static int
276ecryptfs_fsync(struct file *file, struct dentry *dentry, int datasync)
277{
Christoph Hellwig4c728ef2008-12-22 21:11:15 +0100278 return vfs_fsync(ecryptfs_file_to_lower(file),
279 ecryptfs_dentry_to_lower(dentry),
280 datasync);
Michael Halcrow237fead2006-10-04 02:16:22 -0700281}
282
283static int ecryptfs_fasync(int fd, struct file *file, int flag)
284{
285 int rc = 0;
286 struct file *lower_file = NULL;
287
Jonathan Corbetdda64452008-06-19 16:18:25 -0600288 lock_kernel();
Michael Halcrow237fead2006-10-04 02:16:22 -0700289 lower_file = ecryptfs_file_to_lower(file);
290 if (lower_file->f_op && lower_file->f_op->fasync)
291 rc = lower_file->f_op->fasync(fd, lower_file, flag);
Jonathan Corbetdda64452008-06-19 16:18:25 -0600292 unlock_kernel();
Michael Halcrow237fead2006-10-04 02:16:22 -0700293 return rc;
294}
295
Michael Halcrow237fead2006-10-04 02:16:22 -0700296static int ecryptfs_ioctl(struct inode *inode, struct file *file,
297 unsigned int cmd, unsigned long arg);
298
299const struct file_operations ecryptfs_dir_fops = {
300 .readdir = ecryptfs_readdir,
301 .ioctl = ecryptfs_ioctl,
302 .mmap = generic_file_mmap,
303 .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}