fuse: another open-coded file_inode()
[linux-2.6-block.git] / fs / ecryptfs / file.c
CommitLineData
237fead6
MH
1/**
2 * eCryptfs: Linux filesystem encryption layer
3 *
4 * Copyright (C) 1997-2004 Erez Zadok
5 * Copyright (C) 2001-2004 Stony Brook University
dd2a3b7a 6 * Copyright (C) 2004-2007 International Business Machines Corp.
237fead6
MH
7 * 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>
5a0e3ad6 28#include <linux/slab.h>
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MH
29#include <linux/mount.h>
30#include <linux/pagemap.h>
31#include <linux/security.h>
237fead6 32#include <linux/compat.h>
0cc72dc7 33#include <linux/fs_stack.h>
a27bb332 34#include <linux/aio.h>
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35#include "ecryptfs_kernel.h"
36
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37/**
38 * 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{
38a708d7 51 ssize_t rc;
68ac1234 52 struct path lower;
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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) {
68ac1234
AV
63 lower.dentry = ecryptfs_dentry_to_lower(file->f_path.dentry);
64 lower.mnt = ecryptfs_dentry_to_lower_mnt(file->f_path.dentry);
65 touch_atime(&lower);
237fead6
MH
66 }
67 return rc;
68}
69
70struct ecryptfs_getdents_callback {
5c0ba4e0 71 struct dir_context ctx;
2de5f059 72 struct dir_context *caller;
237fead6 73 struct dentry *dentry;
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74 int filldir_called;
75 int entries_written;
76};
77
7d6c7045 78/* Inspired by generic filldir in fs/readdir.c */
237fead6 79static int
addd65ad
MH
80ecryptfs_filldir(void *dirent, const char *lower_name, int lower_namelen,
81 loff_t offset, u64 ino, unsigned int d_type)
237fead6 82{
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MH
83 struct ecryptfs_getdents_callback *buf =
84 (struct ecryptfs_getdents_callback *)dirent;
a8f12864 85 size_t name_size;
addd65ad 86 char *name;
237fead6 87 int rc;
237fead6 88
237fead6 89 buf->filldir_called++;
addd65ad
MH
90 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);
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97 goto out;
98 }
2de5f059
AV
99 buf->caller->pos = buf->ctx.pos;
100 rc = !dir_emit(buf->caller, name, name_size, ino, d_type);
addd65ad 101 kfree(name);
2de5f059 102 if (!rc)
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MH
103 buf->entries_written++;
104out:
105 return rc;
106}
107
108/**
109 * ecryptfs_readdir
addd65ad 110 * @file: The eCryptfs directory file
2de5f059 111 * @ctx: The actor to feed the entries to
237fead6 112 */
2de5f059 113static int ecryptfs_readdir(struct file *file, struct dir_context *ctx)
237fead6
MH
114{
115 int rc;
116 struct file *lower_file;
117 struct inode *inode;
2de5f059
AV
118 struct ecryptfs_getdents_callback buf = {
119 .ctx.actor = ecryptfs_filldir,
120 .caller = ctx,
121 .dentry = file->f_path.dentry
122 };
237fead6 123 lower_file = ecryptfs_file_to_lower(file);
2de5f059 124 lower_file->f_pos = ctx->pos;
496ad9aa 125 inode = file_inode(file);
5c0ba4e0 126 rc = iterate_dir(lower_file, &buf.ctx);
2de5f059 127 ctx->pos = buf.ctx.pos;
7d6c7045
MH
128 if (rc < 0)
129 goto out;
130 if (buf.filldir_called && !buf.entries_written)
131 goto out;
237fead6 132 if (rc >= 0)
7d6c7045 133 fsstack_copy_attr_atime(inode,
496ad9aa 134 file_inode(lower_file));
7d6c7045 135out:
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136 return rc;
137}
138
139struct kmem_cache *ecryptfs_file_info_cache;
140
e3ccaa97
TH
141static int read_or_initialize_metadata(struct dentry *dentry)
142{
143 struct inode *inode = dentry->d_inode;
144 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
145 struct ecryptfs_crypt_stat *crypt_stat;
146 int rc;
147
148 crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
149 mount_crypt_stat = &ecryptfs_superblock_to_private(
150 inode->i_sb)->mount_crypt_stat;
151 mutex_lock(&crypt_stat->cs_mutex);
152
153 if (crypt_stat->flags & ECRYPTFS_POLICY_APPLIED &&
154 crypt_stat->flags & ECRYPTFS_KEY_VALID) {
155 rc = 0;
156 goto out;
157 }
158
159 rc = ecryptfs_read_metadata(dentry);
160 if (!rc)
161 goto out;
162
163 if (mount_crypt_stat->flags & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED) {
164 crypt_stat->flags &= ~(ECRYPTFS_I_SIZE_INITIALIZED
165 | ECRYPTFS_ENCRYPTED);
166 rc = 0;
167 goto out;
168 }
169
170 if (!(mount_crypt_stat->flags & ECRYPTFS_XATTR_METADATA_ENABLED) &&
171 !i_size_read(ecryptfs_inode_to_lower(inode))) {
172 rc = ecryptfs_initialize_file(dentry, inode);
173 if (!rc)
174 goto out;
175 }
176
177 rc = -EIO;
178out:
179 mutex_unlock(&crypt_stat->cs_mutex);
180 return rc;
181}
182
237fead6
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183/**
184 * ecryptfs_open
185 * @inode: inode speciying file to open
186 * @file: Structure to return filled in
187 *
188 * Opens the file specified by inode.
189 *
190 * Returns zero on success; non-zero otherwise
191 */
192static int ecryptfs_open(struct inode *inode, struct file *file)
193{
194 int rc = 0;
195 struct ecryptfs_crypt_stat *crypt_stat = NULL;
196 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
bd243a4b 197 struct dentry *ecryptfs_dentry = file->f_path.dentry;
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198 /* Private value of ecryptfs_dentry allocated in
199 * ecryptfs_lookup() */
237fead6 200 struct ecryptfs_file_info *file_info;
237fead6 201
e77a56dd
MH
202 mount_crypt_stat = &ecryptfs_superblock_to_private(
203 ecryptfs_dentry->d_sb)->mount_crypt_stat;
204 if ((mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
205 && ((file->f_flags & O_WRONLY) || (file->f_flags & O_RDWR)
206 || (file->f_flags & O_CREAT) || (file->f_flags & O_TRUNC)
207 || (file->f_flags & O_APPEND))) {
208 printk(KERN_WARNING "Mount has encrypted view enabled; "
209 "files may only be read\n");
210 rc = -EPERM;
211 goto out;
212 }
237fead6 213 /* Released in ecryptfs_release or end of function if failure */
c3762229 214 file_info = kmem_cache_zalloc(ecryptfs_file_info_cache, GFP_KERNEL);
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215 ecryptfs_set_file_private(file, file_info);
216 if (!file_info) {
217 ecryptfs_printk(KERN_ERR,
218 "Error attempting to allocate memory\n");
219 rc = -ENOMEM;
220 goto out;
221 }
237fead6 222 crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
237fead6 223 mutex_lock(&crypt_stat->cs_mutex);
e2bd99ec 224 if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)) {
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225 ecryptfs_printk(KERN_DEBUG, "Setting flags for stat...\n");
226 /* Policy code enabled in future release */
2ed92554
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227 crypt_stat->flags |= (ECRYPTFS_POLICY_APPLIED
228 | ECRYPTFS_ENCRYPTED);
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229 }
230 mutex_unlock(&crypt_stat->cs_mutex);
3b06b3eb 231 rc = ecryptfs_get_lower_file(ecryptfs_dentry, inode);
27992890
RS
232 if (rc) {
233 printk(KERN_ERR "%s: Error attempting to initialize "
332ab16f 234 "the lower file for the dentry with name "
27992890
RS
235 "[%s]; rc = [%d]\n", __func__,
236 ecryptfs_dentry->d_name.name, rc);
237 goto out_free;
72b55fff 238 }
0abe1169
RS
239 if ((ecryptfs_inode_to_private(inode)->lower_file->f_flags & O_ACCMODE)
240 == O_RDONLY && (file->f_flags & O_ACCMODE) != O_RDONLY) {
e27759d7 241 rc = -EPERM;
332ab16f 242 printk(KERN_WARNING "%s: Lower file is RO; eCryptfs "
e27759d7 243 "file must hence be opened RO\n", __func__);
332ab16f 244 goto out_put;
e27759d7 245 }
2ed92554
MH
246 ecryptfs_set_file_lower(
247 file, ecryptfs_inode_to_private(inode)->lower_file);
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248 if (S_ISDIR(ecryptfs_dentry->d_inode->i_mode)) {
249 ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
2f9b12a3 250 mutex_lock(&crypt_stat->cs_mutex);
e2bd99ec 251 crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
2f9b12a3 252 mutex_unlock(&crypt_stat->cs_mutex);
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253 rc = 0;
254 goto out;
255 }
e3ccaa97
TH
256 rc = read_or_initialize_metadata(ecryptfs_dentry);
257 if (rc)
258 goto out_put;
888d57bb
JP
259 ecryptfs_printk(KERN_DEBUG, "inode w/ addr = [0x%p], i_ino = "
260 "[0x%.16lx] size: [0x%.16llx]\n", inode, inode->i_ino,
261 (unsigned long long)i_size_read(inode));
237fead6 262 goto out;
332ab16f
TH
263out_put:
264 ecryptfs_put_lower_file(inode);
2ed92554 265out_free:
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MH
266 kmem_cache_free(ecryptfs_file_info_cache,
267 ecryptfs_file_to_private(file));
268out:
269 return rc;
270}
271
272static int ecryptfs_flush(struct file *file, fl_owner_t td)
273{
64e6651d
TH
274 struct file *lower_file = ecryptfs_file_to_lower(file);
275
276 if (lower_file->f_op && lower_file->f_op->flush) {
277 filemap_write_and_wait(file->f_mapping);
278 return lower_file->f_op->flush(lower_file, td);
279 }
280
281 return 0;
237fead6
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282}
283
284static int ecryptfs_release(struct inode *inode, struct file *file)
285{
332ab16f 286 ecryptfs_put_lower_file(inode);
2ed92554
MH
287 kmem_cache_free(ecryptfs_file_info_cache,
288 ecryptfs_file_to_private(file));
289 return 0;
237fead6
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290}
291
292static int
02c24a82 293ecryptfs_fsync(struct file *file, loff_t start, loff_t end, int datasync)
237fead6 294{
bc5abcf7
TH
295 int rc;
296
297 rc = filemap_write_and_wait(file->f_mapping);
298 if (rc)
299 return rc;
300
821f7494 301 return vfs_fsync(ecryptfs_file_to_lower(file), datasync);
237fead6
MH
302}
303
304static int ecryptfs_fasync(int fd, struct file *file, int flag)
305{
306 int rc = 0;
307 struct file *lower_file = NULL;
308
309 lower_file = ecryptfs_file_to_lower(file);
310 if (lower_file->f_op && lower_file->f_op->fasync)
311 rc = lower_file->f_op->fasync(fd, lower_file, flag);
312 return rc;
313}
314
c43f7b8f
TH
315static long
316ecryptfs_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
317{
318 struct file *lower_file = NULL;
319 long rc = -ENOTTY;
320
321 if (ecryptfs_file_to_private(file))
322 lower_file = ecryptfs_file_to_lower(file);
323 if (lower_file && lower_file->f_op && lower_file->f_op->unlocked_ioctl)
324 rc = lower_file->f_op->unlocked_ioctl(lower_file, cmd, arg);
325 return rc;
326}
327
328#ifdef CONFIG_COMPAT
329static long
330ecryptfs_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
331{
332 struct file *lower_file = NULL;
333 long rc = -ENOIOCTLCMD;
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->compat_ioctl)
338 rc = lower_file->f_op->compat_ioctl(lower_file, cmd, arg);
339 return rc;
340}
341#endif
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342
343const struct file_operations ecryptfs_dir_fops = {
2de5f059 344 .iterate = ecryptfs_readdir,
323ef68f 345 .read = generic_read_dir,
c43f7b8f
TH
346 .unlocked_ioctl = ecryptfs_unlocked_ioctl,
347#ifdef CONFIG_COMPAT
348 .compat_ioctl = ecryptfs_compat_ioctl,
349#endif
237fead6
MH
350 .open = ecryptfs_open,
351 .flush = ecryptfs_flush,
352 .release = ecryptfs_release,
353 .fsync = ecryptfs_fsync,
354 .fasync = ecryptfs_fasync,
e9f6a99c 355 .splice_read = generic_file_splice_read,
6038f373 356 .llseek = default_llseek,
237fead6
MH
357};
358
359const struct file_operations ecryptfs_main_fops = {
53a2731f 360 .llseek = generic_file_llseek,
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MH
361 .read = do_sync_read,
362 .aio_read = ecryptfs_read_update_atime,
363 .write = do_sync_write,
364 .aio_write = generic_file_aio_write,
2de5f059 365 .iterate = ecryptfs_readdir,
c43f7b8f
TH
366 .unlocked_ioctl = ecryptfs_unlocked_ioctl,
367#ifdef CONFIG_COMPAT
368 .compat_ioctl = ecryptfs_compat_ioctl,
369#endif
821f7494 370 .mmap = generic_file_mmap,
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MH
371 .open = ecryptfs_open,
372 .flush = ecryptfs_flush,
373 .release = ecryptfs_release,
374 .fsync = ecryptfs_fsync,
375 .fasync = ecryptfs_fasync,
e9f6a99c 376 .splice_read = generic_file_splice_read,
237fead6 377};