blob: c98c4690a771c78ad69d3188be2a595be081fa66 [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>
Michael Halcrow237fead2006-10-04 02:16:22 -070033#include "ecryptfs_kernel.h"
34
35/**
Michael Halcrow237fead2006-10-04 02:16:22 -070036 * ecryptfs_read_update_atime
37 *
38 * generic_file_read updates the atime of upper layer inode. But, it
39 * doesn't give us a chance to update the atime of the lower layer
40 * inode. This function is a wrapper to generic_file_read. It
41 * updates the atime of the lower level inode if generic_file_read
42 * returns without any errors. This is to be used only for file reads.
43 * The function to be used for directory reads is ecryptfs_read.
44 */
45static ssize_t ecryptfs_read_update_atime(struct kiocb *iocb,
46 const struct iovec *iov,
47 unsigned long nr_segs, loff_t pos)
48{
49 int rc;
50 struct dentry *lower_dentry;
51 struct vfsmount *lower_vfsmount;
52 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) {
Josef "Jeff" Sipekbd243a42006-12-08 02:36:48 -080062 lower_dentry = ecryptfs_dentry_to_lower(file->f_path.dentry);
63 lower_vfsmount = ecryptfs_dentry_to_lower_mnt(file->f_path.dentry);
Michael Halcrow237fead2006-10-04 02:16:22 -070064 touch_atime(lower_vfsmount, lower_dentry);
65 }
66 return rc;
67}
68
69struct ecryptfs_getdents_callback {
70 void *dirent;
71 struct dentry *dentry;
72 filldir_t filldir;
73 int err;
74 int filldir_called;
75 int entries_written;
76};
77
78/* Inspired by generic filldir in fs/readir.c */
79static int
80ecryptfs_filldir(void *dirent, const char *name, int namelen, loff_t offset,
81 u64 ino, unsigned int d_type)
82{
83 struct ecryptfs_crypt_stat *crypt_stat;
84 struct ecryptfs_getdents_callback *buf =
85 (struct ecryptfs_getdents_callback *)dirent;
86 int rc;
87 int decoded_length;
88 char *decoded_name;
89
90 crypt_stat = ecryptfs_dentry_to_private(buf->dentry)->crypt_stat;
91 buf->filldir_called++;
92 decoded_length = ecryptfs_decode_filename(crypt_stat, name, namelen,
93 &decoded_name);
94 if (decoded_length < 0) {
95 rc = decoded_length;
96 goto out;
97 }
98 rc = buf->filldir(buf->dirent, decoded_name, decoded_length, offset,
99 ino, d_type);
100 kfree(decoded_name);
101 if (rc >= 0)
102 buf->entries_written++;
103out:
104 return rc;
105}
106
107/**
108 * ecryptfs_readdir
109 * @file: The ecryptfs file struct
110 * @dirent: Directory entry
111 * @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;
127retry:
128 buf.filldir_called = 0;
129 buf.entries_written = 0;
130 buf.err = 0;
131 rc = vfs_readdir(lower_file, ecryptfs_filldir, (void *)&buf);
132 if (buf.err)
133 rc = buf.err;
134 if (buf.filldir_called && !buf.entries_written)
135 goto retry;
136 file->f_pos = lower_file->f_pos;
137 if (rc >= 0)
Josef "Jeff" Sipekbd243a42006-12-08 02:36:48 -0800138 fsstack_copy_attr_atime(inode, lower_file->f_path.dentry->d_inode);
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 Halcrow2ed92552007-10-16 01:28:10 -0700194 ecryptfs_set_file_lower(
195 file, ecryptfs_inode_to_private(inode)->lower_file);
Michael Halcrow237fead2006-10-04 02:16:22 -0700196 if (S_ISDIR(ecryptfs_dentry->d_inode->i_mode)) {
197 ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800198 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
Michael Halcrow237fead2006-10-04 02:16:22 -0700199 rc = 0;
200 goto out;
201 }
202 mutex_lock(&crypt_stat->cs_mutex);
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800203 if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)
204 || !(crypt_stat->flags & ECRYPTFS_KEY_VALID)) {
Michael Halcrowd7cdc5f2007-10-16 01:28:10 -0700205 rc = ecryptfs_read_metadata(ecryptfs_dentry);
Michael Halcrow237fead2006-10-04 02:16:22 -0700206 if (rc) {
207 ecryptfs_printk(KERN_DEBUG,
208 "Valid headers not found\n");
209 if (!(mount_crypt_stat->flags
210 & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) {
211 rc = -EIO;
212 printk(KERN_WARNING "Attempt to read file that "
213 "is not in a valid eCryptfs format, "
214 "and plaintext passthrough mode is not "
215 "enabled; returning -EIO\n");
216 mutex_unlock(&crypt_stat->cs_mutex);
Michael Halcrow2ed92552007-10-16 01:28:10 -0700217 goto out_free;
Michael Halcrow237fead2006-10-04 02:16:22 -0700218 }
Michael Halcrow237fead2006-10-04 02:16:22 -0700219 rc = 0;
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800220 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
Michael Halcrow237fead2006-10-04 02:16:22 -0700221 mutex_unlock(&crypt_stat->cs_mutex);
222 goto out;
223 }
224 }
225 mutex_unlock(&crypt_stat->cs_mutex);
226 ecryptfs_printk(KERN_DEBUG, "inode w/ addr = [0x%p], i_ino = [0x%.16x] "
227 "size: [0x%.16x]\n", inode, inode->i_ino,
228 i_size_read(inode));
Michael Halcrow237fead2006-10-04 02:16:22 -0700229 goto out;
Michael Halcrow2ed92552007-10-16 01:28:10 -0700230out_free:
Michael Halcrow237fead2006-10-04 02:16:22 -0700231 kmem_cache_free(ecryptfs_file_info_cache,
232 ecryptfs_file_to_private(file));
233out:
234 return rc;
235}
236
237static int ecryptfs_flush(struct file *file, fl_owner_t td)
238{
239 int rc = 0;
240 struct file *lower_file = NULL;
241
242 lower_file = ecryptfs_file_to_lower(file);
243 if (lower_file->f_op && lower_file->f_op->flush)
244 rc = lower_file->f_op->flush(lower_file, td);
245 return rc;
246}
247
248static int ecryptfs_release(struct inode *inode, struct file *file)
249{
Michael Halcrow2ed92552007-10-16 01:28:10 -0700250 kmem_cache_free(ecryptfs_file_info_cache,
251 ecryptfs_file_to_private(file));
252 return 0;
Michael Halcrow237fead2006-10-04 02:16:22 -0700253}
254
255static int
256ecryptfs_fsync(struct file *file, struct dentry *dentry, int datasync)
257{
258 struct file *lower_file = ecryptfs_file_to_lower(file);
259 struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
260 struct inode *lower_inode = lower_dentry->d_inode;
261 int rc = -EINVAL;
262
263 if (lower_inode->i_fop->fsync) {
264 mutex_lock(&lower_inode->i_mutex);
265 rc = lower_inode->i_fop->fsync(lower_file, lower_dentry,
266 datasync);
267 mutex_unlock(&lower_inode->i_mutex);
268 }
269 return rc;
270}
271
272static int ecryptfs_fasync(int fd, struct file *file, int flag)
273{
274 int rc = 0;
275 struct file *lower_file = NULL;
276
277 lower_file = ecryptfs_file_to_lower(file);
278 if (lower_file->f_op && lower_file->f_op->fasync)
279 rc = lower_file->f_op->fasync(fd, lower_file, flag);
280 return rc;
281}
282
Michael Halcrow237fead2006-10-04 02:16:22 -0700283static int ecryptfs_ioctl(struct inode *inode, struct file *file,
284 unsigned int cmd, unsigned long arg);
285
286const struct file_operations ecryptfs_dir_fops = {
287 .readdir = ecryptfs_readdir,
288 .ioctl = ecryptfs_ioctl,
289 .mmap = generic_file_mmap,
290 .open = ecryptfs_open,
291 .flush = ecryptfs_flush,
292 .release = ecryptfs_release,
293 .fsync = ecryptfs_fsync,
294 .fasync = ecryptfs_fasync,
Michael Halcrowe9f6a992007-10-16 01:28:04 -0700295 .splice_read = generic_file_splice_read,
Michael Halcrow237fead2006-10-04 02:16:22 -0700296};
297
298const struct file_operations ecryptfs_main_fops = {
Michael Halcrow53a27312007-05-23 13:58:15 -0700299 .llseek = generic_file_llseek,
Michael Halcrow237fead2006-10-04 02:16:22 -0700300 .read = do_sync_read,
301 .aio_read = ecryptfs_read_update_atime,
302 .write = do_sync_write,
303 .aio_write = generic_file_aio_write,
304 .readdir = ecryptfs_readdir,
305 .ioctl = ecryptfs_ioctl,
306 .mmap = generic_file_mmap,
307 .open = ecryptfs_open,
308 .flush = ecryptfs_flush,
309 .release = ecryptfs_release,
310 .fsync = ecryptfs_fsync,
311 .fasync = ecryptfs_fasync,
Michael Halcrowe9f6a992007-10-16 01:28:04 -0700312 .splice_read = generic_file_splice_read,
Michael Halcrow237fead2006-10-04 02:16:22 -0700313};
314
315static int
316ecryptfs_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
317 unsigned long arg)
318{
319 int rc = 0;
320 struct file *lower_file = NULL;
321
322 if (ecryptfs_file_to_private(file))
323 lower_file = ecryptfs_file_to_lower(file);
324 if (lower_file && lower_file->f_op && lower_file->f_op->ioctl)
325 rc = lower_file->f_op->ioctl(ecryptfs_inode_to_lower(inode),
326 lower_file, cmd, arg);
327 else
328 rc = -ENOTTY;
329 return rc;
330}