Commit | Line | Data |
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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> | |
28 | #include <linux/mount.h> | |
29 | #include <linux/pagemap.h> | |
30 | #include <linux/security.h> | |
237fead6 | 31 | #include <linux/compat.h> |
0cc72dc7 | 32 | #include <linux/fs_stack.h> |
237fead6 MH |
33 | #include "ecryptfs_kernel.h" |
34 | ||
237fead6 MH |
35 | /** |
36 | * 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 | */ | |
45 | static 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) { | |
bd243a4b JJS |
62 | lower_dentry = ecryptfs_dentry_to_lower(file->f_path.dentry); |
63 | lower_vfsmount = ecryptfs_dentry_to_lower_mnt(file->f_path.dentry); | |
237fead6 MH |
64 | touch_atime(lower_vfsmount, lower_dentry); |
65 | } | |
66 | return rc; | |
67 | } | |
68 | ||
69 | struct 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 */ | |
79 | static int | |
80 | ecryptfs_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++; | |
103 | out: | |
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 | */ | |
113 | static 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; | |
bd243a4b | 122 | inode = file->f_path.dentry->d_inode; |
237fead6 MH |
123 | memset(&buf, 0, sizeof(buf)); |
124 | buf.dirent = dirent; | |
bd243a4b | 125 | buf.dentry = file->f_path.dentry; |
237fead6 MH |
126 | buf.filldir = filldir; |
127 | retry: | |
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) | |
bd243a4b | 138 | fsstack_copy_attr_atime(inode, lower_file->f_path.dentry->d_inode); |
237fead6 MH |
139 | return rc; |
140 | } | |
141 | ||
142 | struct kmem_cache *ecryptfs_file_info_cache; | |
143 | ||
7ff1d74f MH |
144 | int ecryptfs_open_lower_file(struct file **lower_file, |
145 | struct dentry *lower_dentry, | |
146 | struct vfsmount *lower_mnt, int flags) | |
147 | { | |
148 | int rc = 0; | |
149 | ||
a8d547d5 | 150 | flags |= O_LARGEFILE; |
7ff1d74f MH |
151 | dget(lower_dentry); |
152 | mntget(lower_mnt); | |
153 | *lower_file = dentry_open(lower_dentry, lower_mnt, flags); | |
154 | if (IS_ERR(*lower_file)) { | |
155 | printk(KERN_ERR "Error opening lower file for lower_dentry " | |
156 | "[0x%p], lower_mnt [0x%p], and flags [0x%x]\n", | |
157 | lower_dentry, lower_mnt, flags); | |
158 | rc = PTR_ERR(*lower_file); | |
159 | *lower_file = NULL; | |
160 | goto out; | |
161 | } | |
162 | out: | |
163 | return rc; | |
164 | } | |
165 | ||
166 | int ecryptfs_close_lower_file(struct file *lower_file) | |
167 | { | |
168 | fput(lower_file); | |
169 | return 0; | |
170 | } | |
171 | ||
237fead6 MH |
172 | /** |
173 | * ecryptfs_open | |
174 | * @inode: inode speciying file to open | |
175 | * @file: Structure to return filled in | |
176 | * | |
177 | * Opens the file specified by inode. | |
178 | * | |
179 | * Returns zero on success; non-zero otherwise | |
180 | */ | |
181 | static int ecryptfs_open(struct inode *inode, struct file *file) | |
182 | { | |
183 | int rc = 0; | |
184 | struct ecryptfs_crypt_stat *crypt_stat = NULL; | |
185 | struct ecryptfs_mount_crypt_stat *mount_crypt_stat; | |
bd243a4b | 186 | struct dentry *ecryptfs_dentry = file->f_path.dentry; |
237fead6 MH |
187 | /* Private value of ecryptfs_dentry allocated in |
188 | * ecryptfs_lookup() */ | |
189 | struct dentry *lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry); | |
190 | struct inode *lower_inode = NULL; | |
191 | struct file *lower_file = NULL; | |
192 | struct vfsmount *lower_mnt; | |
193 | struct ecryptfs_file_info *file_info; | |
194 | int lower_flags; | |
195 | ||
e77a56dd MH |
196 | mount_crypt_stat = &ecryptfs_superblock_to_private( |
197 | ecryptfs_dentry->d_sb)->mount_crypt_stat; | |
198 | if ((mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED) | |
199 | && ((file->f_flags & O_WRONLY) || (file->f_flags & O_RDWR) | |
200 | || (file->f_flags & O_CREAT) || (file->f_flags & O_TRUNC) | |
201 | || (file->f_flags & O_APPEND))) { | |
202 | printk(KERN_WARNING "Mount has encrypted view enabled; " | |
203 | "files may only be read\n"); | |
204 | rc = -EPERM; | |
205 | goto out; | |
206 | } | |
237fead6 | 207 | /* Released in ecryptfs_release or end of function if failure */ |
c3762229 | 208 | file_info = kmem_cache_zalloc(ecryptfs_file_info_cache, GFP_KERNEL); |
237fead6 MH |
209 | ecryptfs_set_file_private(file, file_info); |
210 | if (!file_info) { | |
211 | ecryptfs_printk(KERN_ERR, | |
212 | "Error attempting to allocate memory\n"); | |
213 | rc = -ENOMEM; | |
214 | goto out; | |
215 | } | |
237fead6 MH |
216 | lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry); |
217 | crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat; | |
237fead6 | 218 | mutex_lock(&crypt_stat->cs_mutex); |
e2bd99ec | 219 | if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)) { |
237fead6 MH |
220 | ecryptfs_printk(KERN_DEBUG, "Setting flags for stat...\n"); |
221 | /* Policy code enabled in future release */ | |
e2bd99ec MH |
222 | crypt_stat->flags |= ECRYPTFS_POLICY_APPLIED; |
223 | crypt_stat->flags |= ECRYPTFS_ENCRYPTED; | |
237fead6 MH |
224 | } |
225 | mutex_unlock(&crypt_stat->cs_mutex); | |
237fead6 MH |
226 | lower_flags = file->f_flags; |
227 | if ((lower_flags & O_ACCMODE) == O_WRONLY) | |
228 | lower_flags = (lower_flags & O_ACCMODE) | O_RDWR; | |
229 | if (file->f_flags & O_APPEND) | |
230 | lower_flags &= ~O_APPEND; | |
231 | lower_mnt = ecryptfs_dentry_to_lower_mnt(ecryptfs_dentry); | |
237fead6 | 232 | /* Corresponding fput() in ecryptfs_release() */ |
5dda6992 MH |
233 | rc = ecryptfs_open_lower_file(&lower_file, lower_dentry, lower_mnt, |
234 | lower_flags); | |
235 | if (rc) { | |
237fead6 MH |
236 | ecryptfs_printk(KERN_ERR, "Error opening lower file\n"); |
237 | goto out_puts; | |
238 | } | |
239 | ecryptfs_set_file_lower(file, lower_file); | |
240 | /* Isn't this check the same as the one in lookup? */ | |
241 | lower_inode = lower_dentry->d_inode; | |
242 | if (S_ISDIR(ecryptfs_dentry->d_inode->i_mode)) { | |
243 | ecryptfs_printk(KERN_DEBUG, "This is a directory\n"); | |
e2bd99ec | 244 | crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED); |
237fead6 MH |
245 | rc = 0; |
246 | goto out; | |
247 | } | |
248 | mutex_lock(&crypt_stat->cs_mutex); | |
e2bd99ec MH |
249 | if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED) |
250 | || !(crypt_stat->flags & ECRYPTFS_KEY_VALID)) { | |
dd2a3b7a | 251 | rc = ecryptfs_read_metadata(ecryptfs_dentry, lower_file); |
237fead6 MH |
252 | if (rc) { |
253 | ecryptfs_printk(KERN_DEBUG, | |
254 | "Valid headers not found\n"); | |
255 | if (!(mount_crypt_stat->flags | |
256 | & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) { | |
257 | rc = -EIO; | |
258 | printk(KERN_WARNING "Attempt to read file that " | |
259 | "is not in a valid eCryptfs format, " | |
260 | "and plaintext passthrough mode is not " | |
261 | "enabled; returning -EIO\n"); | |
262 | mutex_unlock(&crypt_stat->cs_mutex); | |
263 | goto out_puts; | |
264 | } | |
237fead6 | 265 | rc = 0; |
e2bd99ec | 266 | crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED); |
237fead6 MH |
267 | mutex_unlock(&crypt_stat->cs_mutex); |
268 | goto out; | |
269 | } | |
270 | } | |
271 | mutex_unlock(&crypt_stat->cs_mutex); | |
272 | ecryptfs_printk(KERN_DEBUG, "inode w/ addr = [0x%p], i_ino = [0x%.16x] " | |
273 | "size: [0x%.16x]\n", inode, inode->i_ino, | |
274 | i_size_read(inode)); | |
275 | ecryptfs_set_file_lower(file, lower_file); | |
276 | goto out; | |
277 | out_puts: | |
278 | mntput(lower_mnt); | |
279 | dput(lower_dentry); | |
280 | kmem_cache_free(ecryptfs_file_info_cache, | |
281 | ecryptfs_file_to_private(file)); | |
282 | out: | |
283 | return rc; | |
284 | } | |
285 | ||
286 | static int ecryptfs_flush(struct file *file, fl_owner_t td) | |
287 | { | |
288 | int rc = 0; | |
289 | struct file *lower_file = NULL; | |
290 | ||
291 | lower_file = ecryptfs_file_to_lower(file); | |
292 | if (lower_file->f_op && lower_file->f_op->flush) | |
293 | rc = lower_file->f_op->flush(lower_file, td); | |
294 | return rc; | |
295 | } | |
296 | ||
297 | static int ecryptfs_release(struct inode *inode, struct file *file) | |
298 | { | |
299 | struct file *lower_file = ecryptfs_file_to_lower(file); | |
300 | struct ecryptfs_file_info *file_info = ecryptfs_file_to_private(file); | |
301 | struct inode *lower_inode = ecryptfs_inode_to_lower(inode); | |
7ff1d74f | 302 | int rc; |
237fead6 | 303 | |
5dda6992 MH |
304 | rc = ecryptfs_close_lower_file(lower_file); |
305 | if (rc) { | |
7ff1d74f MH |
306 | printk(KERN_ERR "Error closing lower_file\n"); |
307 | goto out; | |
308 | } | |
237fead6 MH |
309 | inode->i_blocks = lower_inode->i_blocks; |
310 | kmem_cache_free(ecryptfs_file_info_cache, file_info); | |
7ff1d74f MH |
311 | out: |
312 | return rc; | |
237fead6 MH |
313 | } |
314 | ||
315 | static int | |
316 | ecryptfs_fsync(struct file *file, struct dentry *dentry, int datasync) | |
317 | { | |
318 | struct file *lower_file = ecryptfs_file_to_lower(file); | |
319 | struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry); | |
320 | struct inode *lower_inode = lower_dentry->d_inode; | |
321 | int rc = -EINVAL; | |
322 | ||
323 | if (lower_inode->i_fop->fsync) { | |
324 | mutex_lock(&lower_inode->i_mutex); | |
325 | rc = lower_inode->i_fop->fsync(lower_file, lower_dentry, | |
326 | datasync); | |
327 | mutex_unlock(&lower_inode->i_mutex); | |
328 | } | |
329 | return rc; | |
330 | } | |
331 | ||
332 | static int ecryptfs_fasync(int fd, struct file *file, int flag) | |
333 | { | |
334 | int rc = 0; | |
335 | struct file *lower_file = NULL; | |
336 | ||
337 | lower_file = ecryptfs_file_to_lower(file); | |
338 | if (lower_file->f_op && lower_file->f_op->fasync) | |
339 | rc = lower_file->f_op->fasync(fd, lower_file, flag); | |
340 | return rc; | |
341 | } | |
342 | ||
237fead6 MH |
343 | static int ecryptfs_ioctl(struct inode *inode, struct file *file, |
344 | unsigned int cmd, unsigned long arg); | |
345 | ||
346 | const struct file_operations ecryptfs_dir_fops = { | |
347 | .readdir = ecryptfs_readdir, | |
348 | .ioctl = ecryptfs_ioctl, | |
349 | .mmap = generic_file_mmap, | |
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, |
237fead6 MH |
356 | }; |
357 | ||
358 | const struct file_operations ecryptfs_main_fops = { | |
53a2731f | 359 | .llseek = generic_file_llseek, |
237fead6 MH |
360 | .read = do_sync_read, |
361 | .aio_read = ecryptfs_read_update_atime, | |
362 | .write = do_sync_write, | |
363 | .aio_write = generic_file_aio_write, | |
364 | .readdir = ecryptfs_readdir, | |
365 | .ioctl = ecryptfs_ioctl, | |
366 | .mmap = generic_file_mmap, | |
367 | .open = ecryptfs_open, | |
368 | .flush = ecryptfs_flush, | |
369 | .release = ecryptfs_release, | |
370 | .fsync = ecryptfs_fsync, | |
371 | .fasync = ecryptfs_fasync, | |
e9f6a99c | 372 | .splice_read = generic_file_splice_read, |
237fead6 MH |
373 | }; |
374 | ||
375 | static int | |
376 | ecryptfs_ioctl(struct inode *inode, struct file *file, unsigned int cmd, | |
377 | unsigned long arg) | |
378 | { | |
379 | int rc = 0; | |
380 | struct file *lower_file = NULL; | |
381 | ||
382 | if (ecryptfs_file_to_private(file)) | |
383 | lower_file = ecryptfs_file_to_lower(file); | |
384 | if (lower_file && lower_file->f_op && lower_file->f_op->ioctl) | |
385 | rc = lower_file->f_op->ioctl(ecryptfs_inode_to_lower(inode), | |
386 | lower_file, cmd, arg); | |
387 | else | |
388 | rc = -ENOTTY; | |
389 | return rc; | |
390 | } |