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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>
Kent Overstreeta27bb332013-05-07 16:19:08 -070034#include <linux/aio.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{
Edward Shishkin38a708d2010-10-30 00:11:50 +020051 ssize_t rc;
Matthew Wilcoxcc18ec32013-06-15 07:55:59 -040052 struct path *path;
Michael Halcrow237fead2006-10-04 02:16:22 -070053 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) {
Matthew Wilcoxcc18ec32013-06-15 07:55:59 -040063 path = ecryptfs_dentry_to_lower_path(file->f_path.dentry);
64 touch_atime(path);
Michael Halcrow237fead2006-10-04 02:16:22 -070065 }
66 return rc;
67}
68
69struct ecryptfs_getdents_callback {
Al Viro5c0ba4e2013-05-15 13:52:59 -040070 struct dir_context ctx;
Al Viro2de5f052013-05-22 21:23:40 -040071 struct dir_context *caller;
Al Viro0747fdb2013-06-16 20:05:38 +040072 struct super_block *sb;
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,
Al Viro0747fdb2013-06-16 20:05:38 +040090 buf->sb, lower_name,
Michael Halcrowaddd65ad2009-01-06 14:42:00 -080091 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 }
Al Viro2de5f052013-05-22 21:23:40 -040098 buf->caller->pos = buf->ctx.pos;
99 rc = !dir_emit(buf->caller, name, name_size, ino, d_type);
Michael Halcrowaddd65ad2009-01-06 14:42:00 -0800100 kfree(name);
Al Viro2de5f052013-05-22 21:23:40 -0400101 if (!rc)
Michael Halcrow237fead2006-10-04 02:16:22 -0700102 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
Al Viro2de5f052013-05-22 21:23:40 -0400110 * @ctx: The actor to feed the entries to
Michael Halcrow237fead2006-10-04 02:16:22 -0700111 */
Al Viro2de5f052013-05-22 21:23:40 -0400112static int ecryptfs_readdir(struct file *file, struct dir_context *ctx)
Michael Halcrow237fead2006-10-04 02:16:22 -0700113{
114 int rc;
115 struct file *lower_file;
Al Viro0747fdb2013-06-16 20:05:38 +0400116 struct inode *inode = file_inode(file);
Al Viro2de5f052013-05-22 21:23:40 -0400117 struct ecryptfs_getdents_callback buf = {
118 .ctx.actor = ecryptfs_filldir,
119 .caller = ctx,
Al Viro0747fdb2013-06-16 20:05:38 +0400120 .sb = inode->i_sb,
Al Viro2de5f052013-05-22 21:23:40 -0400121 };
Michael Halcrow237fead2006-10-04 02:16:22 -0700122 lower_file = ecryptfs_file_to_lower(file);
Al Viro2de5f052013-05-22 21:23:40 -0400123 lower_file->f_pos = ctx->pos;
Al Viro5c0ba4e2013-05-15 13:52:59 -0400124 rc = iterate_dir(lower_file, &buf.ctx);
Al Viro2de5f052013-05-22 21:23:40 -0400125 ctx->pos = buf.ctx.pos;
Michael Halcrow7d6c7042008-10-15 22:02:49 -0700126 if (rc < 0)
127 goto out;
128 if (buf.filldir_called && !buf.entries_written)
129 goto out;
Michael Halcrow237fead2006-10-04 02:16:22 -0700130 if (rc >= 0)
Michael Halcrow7d6c7042008-10-15 22:02:49 -0700131 fsstack_copy_attr_atime(inode,
Al Viro496ad9a2013-01-23 17:07:38 -0500132 file_inode(lower_file));
Michael Halcrow7d6c7042008-10-15 22:02:49 -0700133out:
Michael Halcrow237fead2006-10-04 02:16:22 -0700134 return rc;
135}
136
137struct kmem_cache *ecryptfs_file_info_cache;
138
Tyler Hickse3ccaa92012-06-20 23:50:59 -0700139static int read_or_initialize_metadata(struct dentry *dentry)
140{
141 struct inode *inode = dentry->d_inode;
142 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
143 struct ecryptfs_crypt_stat *crypt_stat;
144 int rc;
145
146 crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
147 mount_crypt_stat = &ecryptfs_superblock_to_private(
148 inode->i_sb)->mount_crypt_stat;
149 mutex_lock(&crypt_stat->cs_mutex);
150
151 if (crypt_stat->flags & ECRYPTFS_POLICY_APPLIED &&
152 crypt_stat->flags & ECRYPTFS_KEY_VALID) {
153 rc = 0;
154 goto out;
155 }
156
157 rc = ecryptfs_read_metadata(dentry);
158 if (!rc)
159 goto out;
160
161 if (mount_crypt_stat->flags & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED) {
162 crypt_stat->flags &= ~(ECRYPTFS_I_SIZE_INITIALIZED
163 | ECRYPTFS_ENCRYPTED);
164 rc = 0;
165 goto out;
166 }
167
168 if (!(mount_crypt_stat->flags & ECRYPTFS_XATTR_METADATA_ENABLED) &&
169 !i_size_read(ecryptfs_inode_to_lower(inode))) {
170 rc = ecryptfs_initialize_file(dentry, inode);
171 if (!rc)
172 goto out;
173 }
174
175 rc = -EIO;
176out:
177 mutex_unlock(&crypt_stat->cs_mutex);
178 return rc;
179}
180
Michael Halcrow237fead2006-10-04 02:16:22 -0700181/**
182 * ecryptfs_open
183 * @inode: inode speciying file to open
184 * @file: Structure to return filled in
185 *
186 * Opens the file specified by inode.
187 *
188 * Returns zero on success; non-zero otherwise
189 */
190static int ecryptfs_open(struct inode *inode, struct file *file)
191{
192 int rc = 0;
193 struct ecryptfs_crypt_stat *crypt_stat = NULL;
194 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
Josef "Jeff" Sipekbd243a42006-12-08 02:36:48 -0800195 struct dentry *ecryptfs_dentry = file->f_path.dentry;
Michael Halcrow237fead2006-10-04 02:16:22 -0700196 /* Private value of ecryptfs_dentry allocated in
197 * ecryptfs_lookup() */
Michael Halcrow237fead2006-10-04 02:16:22 -0700198 struct ecryptfs_file_info *file_info;
Michael Halcrow237fead2006-10-04 02:16:22 -0700199
Michael Halcrowe77a56d2007-02-12 00:53:47 -0800200 mount_crypt_stat = &ecryptfs_superblock_to_private(
201 ecryptfs_dentry->d_sb)->mount_crypt_stat;
202 if ((mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
203 && ((file->f_flags & O_WRONLY) || (file->f_flags & O_RDWR)
204 || (file->f_flags & O_CREAT) || (file->f_flags & O_TRUNC)
205 || (file->f_flags & O_APPEND))) {
206 printk(KERN_WARNING "Mount has encrypted view enabled; "
207 "files may only be read\n");
208 rc = -EPERM;
209 goto out;
210 }
Michael Halcrow237fead2006-10-04 02:16:22 -0700211 /* Released in ecryptfs_release or end of function if failure */
Robert P. J. Dayc3762222007-02-10 01:45:03 -0800212 file_info = kmem_cache_zalloc(ecryptfs_file_info_cache, GFP_KERNEL);
Michael Halcrow237fead2006-10-04 02:16:22 -0700213 ecryptfs_set_file_private(file, file_info);
214 if (!file_info) {
215 ecryptfs_printk(KERN_ERR,
216 "Error attempting to allocate memory\n");
217 rc = -ENOMEM;
218 goto out;
219 }
Michael Halcrow237fead2006-10-04 02:16:22 -0700220 crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
Michael Halcrow237fead2006-10-04 02:16:22 -0700221 mutex_lock(&crypt_stat->cs_mutex);
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800222 if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)) {
Michael Halcrow237fead2006-10-04 02:16:22 -0700223 ecryptfs_printk(KERN_DEBUG, "Setting flags for stat...\n");
224 /* Policy code enabled in future release */
Michael Halcrow2ed92552007-10-16 01:28:10 -0700225 crypt_stat->flags |= (ECRYPTFS_POLICY_APPLIED
226 | ECRYPTFS_ENCRYPTED);
Michael Halcrow237fead2006-10-04 02:16:22 -0700227 }
228 mutex_unlock(&crypt_stat->cs_mutex);
Tyler Hicks3b06b3e2011-05-24 03:49:02 -0500229 rc = ecryptfs_get_lower_file(ecryptfs_dentry, inode);
Roberto Sassu27992892010-11-03 11:11:28 +0100230 if (rc) {
231 printk(KERN_ERR "%s: Error attempting to initialize "
Tyler Hicks332ab162011-04-14 15:35:11 -0500232 "the lower file for the dentry with name "
Roberto Sassu27992892010-11-03 11:11:28 +0100233 "[%s]; rc = [%d]\n", __func__,
234 ecryptfs_dentry->d_name.name, rc);
235 goto out_free;
Michael Halcrow72b55ff2008-07-23 21:30:07 -0700236 }
Roberto Sassu0abe1162010-11-03 11:11:34 +0100237 if ((ecryptfs_inode_to_private(inode)->lower_file->f_flags & O_ACCMODE)
238 == O_RDONLY && (file->f_flags & O_ACCMODE) != O_RDONLY) {
Erez Zadoke27759d2009-12-03 13:35:27 -0500239 rc = -EPERM;
Tyler Hicks332ab162011-04-14 15:35:11 -0500240 printk(KERN_WARNING "%s: Lower file is RO; eCryptfs "
Erez Zadoke27759d2009-12-03 13:35:27 -0500241 "file must hence be opened RO\n", __func__);
Tyler Hicks332ab162011-04-14 15:35:11 -0500242 goto out_put;
Erez Zadoke27759d2009-12-03 13:35:27 -0500243 }
Michael Halcrow2ed92552007-10-16 01:28:10 -0700244 ecryptfs_set_file_lower(
245 file, ecryptfs_inode_to_private(inode)->lower_file);
Michael Halcrow237fead2006-10-04 02:16:22 -0700246 if (S_ISDIR(ecryptfs_dentry->d_inode->i_mode)) {
247 ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
Michael Halcrow2f9b12a2008-04-29 00:59:52 -0700248 mutex_lock(&crypt_stat->cs_mutex);
Michael Halcrowe2bd99e2007-02-12 00:53:49 -0800249 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
Michael Halcrow2f9b12a2008-04-29 00:59:52 -0700250 mutex_unlock(&crypt_stat->cs_mutex);
Michael Halcrow237fead2006-10-04 02:16:22 -0700251 rc = 0;
252 goto out;
253 }
Tyler Hickse3ccaa92012-06-20 23:50:59 -0700254 rc = read_or_initialize_metadata(ecryptfs_dentry);
255 if (rc)
256 goto out_put;
Joe Perches888d57b2010-11-10 15:46:16 -0800257 ecryptfs_printk(KERN_DEBUG, "inode w/ addr = [0x%p], i_ino = "
258 "[0x%.16lx] size: [0x%.16llx]\n", inode, inode->i_ino,
259 (unsigned long long)i_size_read(inode));
Michael Halcrow237fead2006-10-04 02:16:22 -0700260 goto out;
Tyler Hicks332ab162011-04-14 15:35:11 -0500261out_put:
262 ecryptfs_put_lower_file(inode);
Michael Halcrow2ed92552007-10-16 01:28:10 -0700263out_free:
Michael Halcrow237fead2006-10-04 02:16:22 -0700264 kmem_cache_free(ecryptfs_file_info_cache,
265 ecryptfs_file_to_private(file));
266out:
267 return rc;
268}
269
270static int ecryptfs_flush(struct file *file, fl_owner_t td)
271{
Tyler Hicks64e66512012-09-12 18:38:00 -0700272 struct file *lower_file = ecryptfs_file_to_lower(file);
273
Al Viro72c2d532013-09-22 16:27:52 -0400274 if (lower_file->f_op->flush) {
Tyler Hicks64e66512012-09-12 18:38:00 -0700275 filemap_write_and_wait(file->f_mapping);
276 return lower_file->f_op->flush(lower_file, td);
277 }
278
279 return 0;
Michael Halcrow237fead2006-10-04 02:16:22 -0700280}
281
282static int ecryptfs_release(struct inode *inode, struct file *file)
283{
Tyler Hicks332ab162011-04-14 15:35:11 -0500284 ecryptfs_put_lower_file(inode);
Michael Halcrow2ed92552007-10-16 01:28:10 -0700285 kmem_cache_free(ecryptfs_file_info_cache,
286 ecryptfs_file_to_private(file));
287 return 0;
Michael Halcrow237fead2006-10-04 02:16:22 -0700288}
289
290static int
Josef Bacik02c24a82011-07-16 20:44:56 -0400291ecryptfs_fsync(struct file *file, loff_t start, loff_t end, int datasync)
Michael Halcrow237fead2006-10-04 02:16:22 -0700292{
Tyler Hicksbc5abcf2013-06-04 10:24:56 -0700293 int rc;
294
295 rc = filemap_write_and_wait(file->f_mapping);
296 if (rc)
297 return rc;
298
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);
Al Viro72c2d532013-09-22 16:27:52 -0400308 if (lower_file->f_op->fasync)
Michael Halcrow237fead2006-10-04 02:16:22 -0700309 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{
Tyler Hicks2000f5b2013-11-13 10:09:42 -0800316 struct file *lower_file = ecryptfs_file_to_lower(file);
Tyler Hicksc43f7b82009-11-03 11:45:11 -0600317 long rc = -ENOTTY;
318
Al Virobdd35362013-11-09 22:19:48 -0500319 if (lower_file->f_op->unlocked_ioctl)
Tyler Hicksc43f7b82009-11-03 11:45:11 -0600320 rc = lower_file->f_op->unlocked_ioctl(lower_file, cmd, arg);
321 return rc;
322}
323
324#ifdef CONFIG_COMPAT
325static long
326ecryptfs_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
327{
Tyler Hicks2000f5b2013-11-13 10:09:42 -0800328 struct file *lower_file = ecryptfs_file_to_lower(file);
Tyler Hicksc43f7b82009-11-03 11:45:11 -0600329 long rc = -ENOIOCTLCMD;
330
Al Viro72c2d532013-09-22 16:27:52 -0400331 if (lower_file->f_op && lower_file->f_op->compat_ioctl)
Tyler Hicksc43f7b82009-11-03 11:45:11 -0600332 rc = lower_file->f_op->compat_ioctl(lower_file, cmd, arg);
333 return rc;
334}
335#endif
Michael Halcrow237fead2006-10-04 02:16:22 -0700336
337const struct file_operations ecryptfs_dir_fops = {
Al Viro2de5f052013-05-22 21:23:40 -0400338 .iterate = ecryptfs_readdir,
Andy Whitcroft323ef682011-02-16 04:49:59 +0000339 .read = generic_read_dir,
Tyler Hicksc43f7b82009-11-03 11:45:11 -0600340 .unlocked_ioctl = ecryptfs_unlocked_ioctl,
341#ifdef CONFIG_COMPAT
342 .compat_ioctl = ecryptfs_compat_ioctl,
343#endif
Michael Halcrow237fead2006-10-04 02:16:22 -0700344 .open = ecryptfs_open,
345 .flush = ecryptfs_flush,
346 .release = ecryptfs_release,
347 .fsync = ecryptfs_fsync,
348 .fasync = ecryptfs_fasync,
Michael Halcrowe9f6a992007-10-16 01:28:04 -0700349 .splice_read = generic_file_splice_read,
Arnd Bergmann6038f372010-08-15 18:52:59 +0200350 .llseek = default_llseek,
Michael Halcrow237fead2006-10-04 02:16:22 -0700351};
352
353const struct file_operations ecryptfs_main_fops = {
Michael Halcrow53a27312007-05-23 13:58:15 -0700354 .llseek = generic_file_llseek,
Michael Halcrow237fead2006-10-04 02:16:22 -0700355 .read = do_sync_read,
356 .aio_read = ecryptfs_read_update_atime,
357 .write = do_sync_write,
358 .aio_write = generic_file_aio_write,
Al Viro2de5f052013-05-22 21:23:40 -0400359 .iterate = ecryptfs_readdir,
Tyler Hicksc43f7b82009-11-03 11:45:11 -0600360 .unlocked_ioctl = ecryptfs_unlocked_ioctl,
361#ifdef CONFIG_COMPAT
362 .compat_ioctl = ecryptfs_compat_ioctl,
363#endif
Tyler Hicks821f7492012-07-03 16:50:57 -0700364 .mmap = generic_file_mmap,
Michael Halcrow237fead2006-10-04 02:16:22 -0700365 .open = ecryptfs_open,
366 .flush = ecryptfs_flush,
367 .release = ecryptfs_release,
368 .fsync = ecryptfs_fsync,
369 .fasync = ecryptfs_fasync,
Michael Halcrowe9f6a992007-10-16 01:28:04 -0700370 .splice_read = generic_file_splice_read,
Michael Halcrow237fead2006-10-04 02:16:22 -0700371};