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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>
237fead6
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>
237fead6
MH
34#include "ecryptfs_kernel.h"
35
237fead6
MH
36/**
37 * 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,
02797829 47 struct iov_iter *to)
237fead6 48{
38a708d7 49 ssize_t rc;
cc18ec3c 50 struct path *path;
237fead6
MH
51 struct file *file = iocb->ki_filp;
52
02797829 53 rc = generic_file_read_iter(iocb, to);
237fead6 54 if (rc >= 0) {
cc18ec3c
MW
55 path = ecryptfs_dentry_to_lower_path(file->f_path.dentry);
56 touch_atime(path);
237fead6
MH
57 }
58 return rc;
59}
60
61struct ecryptfs_getdents_callback {
5c0ba4e0 62 struct dir_context ctx;
2de5f059 63 struct dir_context *caller;
0747fdb2 64 struct super_block *sb;
237fead6
MH
65 int filldir_called;
66 int entries_written;
67};
68
7d6c7045 69/* Inspired by generic filldir in fs/readdir.c */
237fead6 70static int
ac7576f4
MS
71ecryptfs_filldir(struct dir_context *ctx, const char *lower_name,
72 int lower_namelen, loff_t offset, u64 ino, unsigned int d_type)
237fead6 73{
237fead6 74 struct ecryptfs_getdents_callback *buf =
ac7576f4 75 container_of(ctx, struct ecryptfs_getdents_callback, ctx);
a8f12864 76 size_t name_size;
addd65ad 77 char *name;
237fead6 78 int rc;
237fead6 79
237fead6 80 buf->filldir_called++;
addd65ad 81 rc = ecryptfs_decode_and_decrypt_filename(&name, &name_size,
0747fdb2 82 buf->sb, lower_name,
addd65ad
MH
83 lower_namelen);
84 if (rc) {
85 printk(KERN_ERR "%s: Error attempting to decode and decrypt "
86 "filename [%s]; rc = [%d]\n", __func__, lower_name,
87 rc);
237fead6
MH
88 goto out;
89 }
2de5f059
AV
90 buf->caller->pos = buf->ctx.pos;
91 rc = !dir_emit(buf->caller, name, name_size, ino, d_type);
addd65ad 92 kfree(name);
2de5f059 93 if (!rc)
237fead6
MH
94 buf->entries_written++;
95out:
96 return rc;
97}
98
99/**
100 * ecryptfs_readdir
addd65ad 101 * @file: The eCryptfs directory file
2de5f059 102 * @ctx: The actor to feed the entries to
237fead6 103 */
2de5f059 104static int ecryptfs_readdir(struct file *file, struct dir_context *ctx)
237fead6
MH
105{
106 int rc;
107 struct file *lower_file;
0747fdb2 108 struct inode *inode = file_inode(file);
2de5f059
AV
109 struct ecryptfs_getdents_callback buf = {
110 .ctx.actor = ecryptfs_filldir,
111 .caller = ctx,
0747fdb2 112 .sb = inode->i_sb,
2de5f059 113 };
237fead6 114 lower_file = ecryptfs_file_to_lower(file);
5c0ba4e0 115 rc = iterate_dir(lower_file, &buf.ctx);
2de5f059 116 ctx->pos = buf.ctx.pos;
7d6c7045
MH
117 if (rc < 0)
118 goto out;
119 if (buf.filldir_called && !buf.entries_written)
120 goto out;
237fead6 121 if (rc >= 0)
7d6c7045 122 fsstack_copy_attr_atime(inode,
496ad9aa 123 file_inode(lower_file));
7d6c7045 124out:
237fead6
MH
125 return rc;
126}
127
128struct kmem_cache *ecryptfs_file_info_cache;
129
e3ccaa97
TH
130static int read_or_initialize_metadata(struct dentry *dentry)
131{
2b0143b5 132 struct inode *inode = d_inode(dentry);
e3ccaa97
TH
133 struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
134 struct ecryptfs_crypt_stat *crypt_stat;
135 int rc;
136
137 crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
138 mount_crypt_stat = &ecryptfs_superblock_to_private(
139 inode->i_sb)->mount_crypt_stat;
140 mutex_lock(&crypt_stat->cs_mutex);
141
142 if (crypt_stat->flags & ECRYPTFS_POLICY_APPLIED &&
143 crypt_stat->flags & ECRYPTFS_KEY_VALID) {
144 rc = 0;
145 goto out;
146 }
147
148 rc = ecryptfs_read_metadata(dentry);
149 if (!rc)
150 goto out;
151
152 if (mount_crypt_stat->flags & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED) {
153 crypt_stat->flags &= ~(ECRYPTFS_I_SIZE_INITIALIZED
154 | ECRYPTFS_ENCRYPTED);
155 rc = 0;
156 goto out;
157 }
158
159 if (!(mount_crypt_stat->flags & ECRYPTFS_XATTR_METADATA_ENABLED) &&
160 !i_size_read(ecryptfs_inode_to_lower(inode))) {
161 rc = ecryptfs_initialize_file(dentry, inode);
162 if (!rc)
163 goto out;
164 }
165
166 rc = -EIO;
167out:
168 mutex_unlock(&crypt_stat->cs_mutex);
169 return rc;
170}
171
f0fe970d
JM
172static int ecryptfs_mmap(struct file *file, struct vm_area_struct *vma)
173{
174 struct file *lower_file = ecryptfs_file_to_lower(file);
175 /*
176 * Don't allow mmap on top of file systems that don't support it
177 * natively. If FILESYSTEM_MAX_STACK_DEPTH > 2 or ecryptfs
178 * allows recursive mounting, this will need to be extended.
179 */
180 if (!lower_file->f_op->mmap)
181 return -ENODEV;
182 return generic_file_mmap(file, vma);
183}
184
237fead6
MH
185/**
186 * ecryptfs_open
40f0fd37 187 * @inode: inode specifying file to open
237fead6
MH
188 * @file: Structure to return filled in
189 *
190 * Opens the file specified by inode.
191 *
192 * Returns zero on success; non-zero otherwise
193 */
194static int ecryptfs_open(struct inode *inode, struct file *file)
195{
196 int rc = 0;
197 struct ecryptfs_crypt_stat *crypt_stat = NULL;
bd243a4b 198 struct dentry *ecryptfs_dentry = file->f_path.dentry;
237fead6
MH
199 /* Private value of ecryptfs_dentry allocated in
200 * ecryptfs_lookup() */
237fead6 201 struct ecryptfs_file_info *file_info;
237fead6
MH
202
203 /* Released in ecryptfs_release or end of function if failure */
c3762229 204 file_info = kmem_cache_zalloc(ecryptfs_file_info_cache, GFP_KERNEL);
237fead6
MH
205 ecryptfs_set_file_private(file, file_info);
206 if (!file_info) {
207 ecryptfs_printk(KERN_ERR,
208 "Error attempting to allocate memory\n");
209 rc = -ENOMEM;
210 goto out;
211 }
237fead6 212 crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
237fead6 213 mutex_lock(&crypt_stat->cs_mutex);
e2bd99ec 214 if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)) {
237fead6
MH
215 ecryptfs_printk(KERN_DEBUG, "Setting flags for stat...\n");
216 /* Policy code enabled in future release */
2ed92554
MH
217 crypt_stat->flags |= (ECRYPTFS_POLICY_APPLIED
218 | ECRYPTFS_ENCRYPTED);
237fead6
MH
219 }
220 mutex_unlock(&crypt_stat->cs_mutex);
3b06b3eb 221 rc = ecryptfs_get_lower_file(ecryptfs_dentry, inode);
27992890
RS
222 if (rc) {
223 printk(KERN_ERR "%s: Error attempting to initialize "
332ab16f 224 "the lower file for the dentry with name "
9e78d14a
DH
225 "[%pd]; rc = [%d]\n", __func__,
226 ecryptfs_dentry, rc);
27992890 227 goto out_free;
72b55fff 228 }
0abe1169
RS
229 if ((ecryptfs_inode_to_private(inode)->lower_file->f_flags & O_ACCMODE)
230 == O_RDONLY && (file->f_flags & O_ACCMODE) != O_RDONLY) {
e27759d7 231 rc = -EPERM;
332ab16f 232 printk(KERN_WARNING "%s: Lower file is RO; eCryptfs "
e27759d7 233 "file must hence be opened RO\n", __func__);
332ab16f 234 goto out_put;
e27759d7 235 }
2ed92554
MH
236 ecryptfs_set_file_lower(
237 file, ecryptfs_inode_to_private(inode)->lower_file);
e3ccaa97
TH
238 rc = read_or_initialize_metadata(ecryptfs_dentry);
239 if (rc)
240 goto out_put;
888d57bb
JP
241 ecryptfs_printk(KERN_DEBUG, "inode w/ addr = [0x%p], i_ino = "
242 "[0x%.16lx] size: [0x%.16llx]\n", inode, inode->i_ino,
243 (unsigned long long)i_size_read(inode));
237fead6 244 goto out;
332ab16f
TH
245out_put:
246 ecryptfs_put_lower_file(inode);
2ed92554 247out_free:
237fead6
MH
248 kmem_cache_free(ecryptfs_file_info_cache,
249 ecryptfs_file_to_private(file));
250out:
251 return rc;
252}
253
6a480a78
AV
254/**
255 * ecryptfs_dir_open
40f0fd37 256 * @inode: inode specifying file to open
6a480a78
AV
257 * @file: Structure to return filled in
258 *
259 * Opens the file specified by inode.
260 *
261 * Returns zero on success; non-zero otherwise
262 */
263static int ecryptfs_dir_open(struct inode *inode, struct file *file)
264{
265 struct dentry *ecryptfs_dentry = file->f_path.dentry;
266 /* Private value of ecryptfs_dentry allocated in
267 * ecryptfs_lookup() */
268 struct ecryptfs_file_info *file_info;
269 struct file *lower_file;
270
271 /* Released in ecryptfs_release or end of function if failure */
272 file_info = kmem_cache_zalloc(ecryptfs_file_info_cache, GFP_KERNEL);
273 ecryptfs_set_file_private(file, file_info);
274 if (unlikely(!file_info)) {
275 ecryptfs_printk(KERN_ERR,
276 "Error attempting to allocate memory\n");
277 return -ENOMEM;
278 }
279 lower_file = dentry_open(ecryptfs_dentry_to_lower_path(ecryptfs_dentry),
280 file->f_flags, current_cred());
281 if (IS_ERR(lower_file)) {
282 printk(KERN_ERR "%s: Error attempting to initialize "
283 "the lower file for the dentry with name "
284 "[%pd]; rc = [%ld]\n", __func__,
285 ecryptfs_dentry, PTR_ERR(lower_file));
286 kmem_cache_free(ecryptfs_file_info_cache, file_info);
287 return PTR_ERR(lower_file);
288 }
289 ecryptfs_set_file_lower(file, lower_file);
290 return 0;
291}
292
237fead6
MH
293static int ecryptfs_flush(struct file *file, fl_owner_t td)
294{
64e6651d
TH
295 struct file *lower_file = ecryptfs_file_to_lower(file);
296
72c2d531 297 if (lower_file->f_op->flush) {
64e6651d
TH
298 filemap_write_and_wait(file->f_mapping);
299 return lower_file->f_op->flush(lower_file, td);
300 }
301
302 return 0;
237fead6
MH
303}
304
305static int ecryptfs_release(struct inode *inode, struct file *file)
306{
332ab16f 307 ecryptfs_put_lower_file(inode);
2ed92554
MH
308 kmem_cache_free(ecryptfs_file_info_cache,
309 ecryptfs_file_to_private(file));
310 return 0;
237fead6
MH
311}
312
6a480a78
AV
313static int ecryptfs_dir_release(struct inode *inode, struct file *file)
314{
315 fput(ecryptfs_file_to_lower(file));
316 kmem_cache_free(ecryptfs_file_info_cache,
317 ecryptfs_file_to_private(file));
318 return 0;
319}
320
321static loff_t ecryptfs_dir_llseek(struct file *file, loff_t offset, int whence)
322{
323 return vfs_llseek(ecryptfs_file_to_lower(file), offset, whence);
324}
325
237fead6 326static int
02c24a82 327ecryptfs_fsync(struct file *file, loff_t start, loff_t end, int datasync)
237fead6 328{
bc5abcf7
TH
329 int rc;
330
331 rc = filemap_write_and_wait(file->f_mapping);
332 if (rc)
333 return rc;
334
821f7494 335 return vfs_fsync(ecryptfs_file_to_lower(file), datasync);
237fead6
MH
336}
337
338static int ecryptfs_fasync(int fd, struct file *file, int flag)
339{
340 int rc = 0;
341 struct file *lower_file = NULL;
342
343 lower_file = ecryptfs_file_to_lower(file);
72c2d531 344 if (lower_file->f_op->fasync)
237fead6
MH
345 rc = lower_file->f_op->fasync(fd, lower_file, flag);
346 return rc;
347}
348
c43f7b8f
TH
349static long
350ecryptfs_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
351{
2000f5be 352 struct file *lower_file = ecryptfs_file_to_lower(file);
c43f7b8f
TH
353 long rc = -ENOTTY;
354
6d65261a
TH
355 if (!lower_file->f_op->unlocked_ioctl)
356 return rc;
357
358 switch (cmd) {
359 case FITRIM:
360 case FS_IOC_GETFLAGS:
361 case FS_IOC_SETFLAGS:
362 case FS_IOC_GETVERSION:
363 case FS_IOC_SETVERSION:
c43f7b8f 364 rc = lower_file->f_op->unlocked_ioctl(lower_file, cmd, arg);
6d65261a
TH
365 fsstack_copy_attr_all(file_inode(file), file_inode(lower_file));
366
367 return rc;
368 default:
369 return rc;
370 }
c43f7b8f
TH
371}
372
373#ifdef CONFIG_COMPAT
374static long
375ecryptfs_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
376{
2000f5be 377 struct file *lower_file = ecryptfs_file_to_lower(file);
c43f7b8f
TH
378 long rc = -ENOIOCTLCMD;
379
6d65261a
TH
380 if (!lower_file->f_op->compat_ioctl)
381 return rc;
382
383 switch (cmd) {
6d65261a
TH
384 case FS_IOC32_GETFLAGS:
385 case FS_IOC32_SETFLAGS:
386 case FS_IOC32_GETVERSION:
387 case FS_IOC32_SETVERSION:
c43f7b8f 388 rc = lower_file->f_op->compat_ioctl(lower_file, cmd, arg);
6d65261a
TH
389 fsstack_copy_attr_all(file_inode(file), file_inode(lower_file));
390
391 return rc;
392 default:
393 return rc;
394 }
c43f7b8f
TH
395}
396#endif
237fead6
MH
397
398const struct file_operations ecryptfs_dir_fops = {
51a16a9c 399 .iterate_shared = ecryptfs_readdir,
323ef68f 400 .read = generic_read_dir,
c43f7b8f
TH
401 .unlocked_ioctl = ecryptfs_unlocked_ioctl,
402#ifdef CONFIG_COMPAT
403 .compat_ioctl = ecryptfs_compat_ioctl,
404#endif
6a480a78
AV
405 .open = ecryptfs_dir_open,
406 .release = ecryptfs_dir_release,
237fead6 407 .fsync = ecryptfs_fsync,
6a480a78 408 .llseek = ecryptfs_dir_llseek,
237fead6
MH
409};
410
411const struct file_operations ecryptfs_main_fops = {
53a2731f 412 .llseek = generic_file_llseek,
02797829 413 .read_iter = ecryptfs_read_update_atime,
8174202b 414 .write_iter = generic_file_write_iter,
c43f7b8f
TH
415 .unlocked_ioctl = ecryptfs_unlocked_ioctl,
416#ifdef CONFIG_COMPAT
417 .compat_ioctl = ecryptfs_compat_ioctl,
418#endif
f0fe970d 419 .mmap = ecryptfs_mmap,
237fead6
MH
420 .open = ecryptfs_open,
421 .flush = ecryptfs_flush,
422 .release = ecryptfs_release,
423 .fsync = ecryptfs_fsync,
424 .fasync = ecryptfs_fasync,
e9f6a99c 425 .splice_read = generic_file_splice_read,
237fead6 426};