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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> |
dda6445e | 33 | #include <linux/smp_lock.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 | */ | |
46 | static ssize_t ecryptfs_read_update_atime(struct kiocb *iocb, | |
47 | const struct iovec *iov, | |
48 | unsigned long nr_segs, loff_t pos) | |
49 | { | |
50 | int rc; | |
51 | struct dentry *lower_dentry; | |
52 | struct vfsmount *lower_vfsmount; | |
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) { | |
bd243a4b JJS |
63 | lower_dentry = ecryptfs_dentry_to_lower(file->f_path.dentry); |
64 | lower_vfsmount = ecryptfs_dentry_to_lower_mnt(file->f_path.dentry); | |
237fead6 MH |
65 | touch_atime(lower_vfsmount, lower_dentry); |
66 | } | |
67 | return rc; | |
68 | } | |
69 | ||
70 | struct ecryptfs_getdents_callback { | |
71 | void *dirent; | |
72 | struct dentry *dentry; | |
73 | filldir_t filldir; | |
74 | int err; | |
75 | int filldir_called; | |
76 | int entries_written; | |
77 | }; | |
78 | ||
79 | /* Inspired by generic filldir in fs/readir.c */ | |
80 | static int | |
81 | ecryptfs_filldir(void *dirent, const char *name, int namelen, loff_t offset, | |
82 | u64 ino, unsigned int d_type) | |
83 | { | |
84 | struct ecryptfs_crypt_stat *crypt_stat; | |
85 | struct ecryptfs_getdents_callback *buf = | |
86 | (struct ecryptfs_getdents_callback *)dirent; | |
87 | int rc; | |
88 | int decoded_length; | |
89 | char *decoded_name; | |
90 | ||
91 | crypt_stat = ecryptfs_dentry_to_private(buf->dentry)->crypt_stat; | |
92 | buf->filldir_called++; | |
93 | decoded_length = ecryptfs_decode_filename(crypt_stat, name, namelen, | |
94 | &decoded_name); | |
95 | if (decoded_length < 0) { | |
96 | rc = decoded_length; | |
97 | goto out; | |
98 | } | |
99 | rc = buf->filldir(buf->dirent, decoded_name, decoded_length, offset, | |
100 | ino, d_type); | |
101 | kfree(decoded_name); | |
102 | if (rc >= 0) | |
103 | buf->entries_written++; | |
104 | out: | |
105 | return rc; | |
106 | } | |
107 | ||
108 | /** | |
109 | * ecryptfs_readdir | |
110 | * @file: The ecryptfs file struct | |
111 | * @dirent: Directory entry | |
112 | * @filldir: The filldir callback function | |
113 | */ | |
114 | static int ecryptfs_readdir(struct file *file, void *dirent, filldir_t filldir) | |
115 | { | |
116 | int rc; | |
117 | struct file *lower_file; | |
118 | struct inode *inode; | |
119 | struct ecryptfs_getdents_callback buf; | |
120 | ||
121 | lower_file = ecryptfs_file_to_lower(file); | |
122 | lower_file->f_pos = file->f_pos; | |
bd243a4b | 123 | inode = file->f_path.dentry->d_inode; |
237fead6 MH |
124 | memset(&buf, 0, sizeof(buf)); |
125 | buf.dirent = dirent; | |
bd243a4b | 126 | buf.dentry = file->f_path.dentry; |
237fead6 MH |
127 | buf.filldir = filldir; |
128 | retry: | |
129 | buf.filldir_called = 0; | |
130 | buf.entries_written = 0; | |
131 | buf.err = 0; | |
132 | rc = vfs_readdir(lower_file, ecryptfs_filldir, (void *)&buf); | |
133 | if (buf.err) | |
134 | rc = buf.err; | |
135 | if (buf.filldir_called && !buf.entries_written) | |
136 | goto retry; | |
137 | file->f_pos = lower_file->f_pos; | |
138 | if (rc >= 0) | |
bd243a4b | 139 | fsstack_copy_attr_atime(inode, lower_file->f_path.dentry->d_inode); |
237fead6 MH |
140 | return rc; |
141 | } | |
142 | ||
143 | struct kmem_cache *ecryptfs_file_info_cache; | |
144 | ||
145 | /** | |
146 | * ecryptfs_open | |
147 | * @inode: inode speciying file to open | |
148 | * @file: Structure to return filled in | |
149 | * | |
150 | * Opens the file specified by inode. | |
151 | * | |
152 | * Returns zero on success; non-zero otherwise | |
153 | */ | |
154 | static int ecryptfs_open(struct inode *inode, struct file *file) | |
155 | { | |
156 | int rc = 0; | |
157 | struct ecryptfs_crypt_stat *crypt_stat = NULL; | |
158 | struct ecryptfs_mount_crypt_stat *mount_crypt_stat; | |
bd243a4b | 159 | struct dentry *ecryptfs_dentry = file->f_path.dentry; |
237fead6 MH |
160 | /* Private value of ecryptfs_dentry allocated in |
161 | * ecryptfs_lookup() */ | |
162 | struct dentry *lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry); | |
237fead6 | 163 | struct ecryptfs_file_info *file_info; |
237fead6 | 164 | |
e77a56dd MH |
165 | mount_crypt_stat = &ecryptfs_superblock_to_private( |
166 | ecryptfs_dentry->d_sb)->mount_crypt_stat; | |
167 | if ((mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED) | |
168 | && ((file->f_flags & O_WRONLY) || (file->f_flags & O_RDWR) | |
169 | || (file->f_flags & O_CREAT) || (file->f_flags & O_TRUNC) | |
170 | || (file->f_flags & O_APPEND))) { | |
171 | printk(KERN_WARNING "Mount has encrypted view enabled; " | |
172 | "files may only be read\n"); | |
173 | rc = -EPERM; | |
174 | goto out; | |
175 | } | |
237fead6 | 176 | /* Released in ecryptfs_release or end of function if failure */ |
c3762229 | 177 | file_info = kmem_cache_zalloc(ecryptfs_file_info_cache, GFP_KERNEL); |
237fead6 MH |
178 | ecryptfs_set_file_private(file, file_info); |
179 | if (!file_info) { | |
180 | ecryptfs_printk(KERN_ERR, | |
181 | "Error attempting to allocate memory\n"); | |
182 | rc = -ENOMEM; | |
183 | goto out; | |
184 | } | |
237fead6 MH |
185 | lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry); |
186 | crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat; | |
237fead6 | 187 | mutex_lock(&crypt_stat->cs_mutex); |
e2bd99ec | 188 | if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)) { |
237fead6 MH |
189 | ecryptfs_printk(KERN_DEBUG, "Setting flags for stat...\n"); |
190 | /* Policy code enabled in future release */ | |
2ed92554 MH |
191 | crypt_stat->flags |= (ECRYPTFS_POLICY_APPLIED |
192 | | ECRYPTFS_ENCRYPTED); | |
237fead6 MH |
193 | } |
194 | mutex_unlock(&crypt_stat->cs_mutex); | |
2ed92554 MH |
195 | ecryptfs_set_file_lower( |
196 | file, ecryptfs_inode_to_private(inode)->lower_file); | |
237fead6 MH |
197 | if (S_ISDIR(ecryptfs_dentry->d_inode->i_mode)) { |
198 | ecryptfs_printk(KERN_DEBUG, "This is a directory\n"); | |
2f9b12a3 | 199 | mutex_lock(&crypt_stat->cs_mutex); |
e2bd99ec | 200 | crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED); |
2f9b12a3 | 201 | mutex_unlock(&crypt_stat->cs_mutex); |
237fead6 MH |
202 | rc = 0; |
203 | goto out; | |
204 | } | |
205 | mutex_lock(&crypt_stat->cs_mutex); | |
e2bd99ec MH |
206 | if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED) |
207 | || !(crypt_stat->flags & ECRYPTFS_KEY_VALID)) { | |
d7cdc5fe | 208 | rc = ecryptfs_read_metadata(ecryptfs_dentry); |
237fead6 MH |
209 | if (rc) { |
210 | ecryptfs_printk(KERN_DEBUG, | |
211 | "Valid headers not found\n"); | |
212 | if (!(mount_crypt_stat->flags | |
213 | & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) { | |
214 | rc = -EIO; | |
25bd8174 | 215 | printk(KERN_WARNING "Either the lower file " |
237fead6 | 216 | "is not in a valid eCryptfs format, " |
25bd8174 MH |
217 | "or the key could not be retrieved. " |
218 | "Plaintext passthrough mode is not " | |
237fead6 MH |
219 | "enabled; returning -EIO\n"); |
220 | mutex_unlock(&crypt_stat->cs_mutex); | |
2ed92554 | 221 | goto out_free; |
237fead6 | 222 | } |
237fead6 | 223 | rc = 0; |
e2bd99ec | 224 | crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED); |
237fead6 MH |
225 | mutex_unlock(&crypt_stat->cs_mutex); |
226 | goto out; | |
227 | } | |
228 | } | |
229 | mutex_unlock(&crypt_stat->cs_mutex); | |
230 | ecryptfs_printk(KERN_DEBUG, "inode w/ addr = [0x%p], i_ino = [0x%.16x] " | |
231 | "size: [0x%.16x]\n", inode, inode->i_ino, | |
232 | i_size_read(inode)); | |
237fead6 | 233 | goto out; |
2ed92554 | 234 | out_free: |
237fead6 MH |
235 | kmem_cache_free(ecryptfs_file_info_cache, |
236 | ecryptfs_file_to_private(file)); | |
237 | out: | |
238 | return rc; | |
239 | } | |
240 | ||
241 | static int ecryptfs_flush(struct file *file, fl_owner_t td) | |
242 | { | |
243 | int rc = 0; | |
244 | struct file *lower_file = NULL; | |
245 | ||
246 | lower_file = ecryptfs_file_to_lower(file); | |
247 | if (lower_file->f_op && lower_file->f_op->flush) | |
248 | rc = lower_file->f_op->flush(lower_file, td); | |
249 | return rc; | |
250 | } | |
251 | ||
252 | static int ecryptfs_release(struct inode *inode, struct file *file) | |
253 | { | |
2ed92554 MH |
254 | kmem_cache_free(ecryptfs_file_info_cache, |
255 | ecryptfs_file_to_private(file)); | |
256 | return 0; | |
237fead6 MH |
257 | } |
258 | ||
259 | static int | |
260 | ecryptfs_fsync(struct file *file, struct dentry *dentry, int datasync) | |
261 | { | |
262 | struct file *lower_file = ecryptfs_file_to_lower(file); | |
263 | struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry); | |
264 | struct inode *lower_inode = lower_dentry->d_inode; | |
265 | int rc = -EINVAL; | |
266 | ||
267 | if (lower_inode->i_fop->fsync) { | |
268 | mutex_lock(&lower_inode->i_mutex); | |
269 | rc = lower_inode->i_fop->fsync(lower_file, lower_dentry, | |
270 | datasync); | |
271 | mutex_unlock(&lower_inode->i_mutex); | |
272 | } | |
273 | return rc; | |
274 | } | |
275 | ||
276 | static int ecryptfs_fasync(int fd, struct file *file, int flag) | |
277 | { | |
278 | int rc = 0; | |
279 | struct file *lower_file = NULL; | |
280 | ||
dda6445e | 281 | lock_kernel(); |
237fead6 MH |
282 | lower_file = ecryptfs_file_to_lower(file); |
283 | if (lower_file->f_op && lower_file->f_op->fasync) | |
284 | rc = lower_file->f_op->fasync(fd, lower_file, flag); | |
dda6445e | 285 | unlock_kernel(); |
237fead6 MH |
286 | return rc; |
287 | } | |
288 | ||
237fead6 MH |
289 | static int ecryptfs_ioctl(struct inode *inode, struct file *file, |
290 | unsigned int cmd, unsigned long arg); | |
291 | ||
292 | const struct file_operations ecryptfs_dir_fops = { | |
293 | .readdir = ecryptfs_readdir, | |
294 | .ioctl = ecryptfs_ioctl, | |
295 | .mmap = generic_file_mmap, | |
296 | .open = ecryptfs_open, | |
297 | .flush = ecryptfs_flush, | |
298 | .release = ecryptfs_release, | |
299 | .fsync = ecryptfs_fsync, | |
300 | .fasync = ecryptfs_fasync, | |
e9f6a99c | 301 | .splice_read = generic_file_splice_read, |
237fead6 MH |
302 | }; |
303 | ||
304 | const struct file_operations ecryptfs_main_fops = { | |
53a2731f | 305 | .llseek = generic_file_llseek, |
237fead6 MH |
306 | .read = do_sync_read, |
307 | .aio_read = ecryptfs_read_update_atime, | |
308 | .write = do_sync_write, | |
309 | .aio_write = generic_file_aio_write, | |
310 | .readdir = ecryptfs_readdir, | |
311 | .ioctl = ecryptfs_ioctl, | |
312 | .mmap = generic_file_mmap, | |
313 | .open = ecryptfs_open, | |
314 | .flush = ecryptfs_flush, | |
315 | .release = ecryptfs_release, | |
316 | .fsync = ecryptfs_fsync, | |
317 | .fasync = ecryptfs_fasync, | |
e9f6a99c | 318 | .splice_read = generic_file_splice_read, |
237fead6 MH |
319 | }; |
320 | ||
321 | static int | |
322 | ecryptfs_ioctl(struct inode *inode, struct file *file, unsigned int cmd, | |
323 | unsigned long arg) | |
324 | { | |
325 | int rc = 0; | |
326 | struct file *lower_file = NULL; | |
327 | ||
328 | if (ecryptfs_file_to_private(file)) | |
329 | lower_file = ecryptfs_file_to_lower(file); | |
330 | if (lower_file && lower_file->f_op && lower_file->f_op->ioctl) | |
331 | rc = lower_file->f_op->ioctl(ecryptfs_inode_to_lower(inode), | |
332 | lower_file, cmd, arg); | |
333 | else | |
334 | rc = -ENOTTY; | |
335 | return rc; | |
336 | } |