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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> | |
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> |
a27bb332 | 34 | #include <linux/aio.h> |
237fead6 MH |
35 | #include "ecryptfs_kernel.h" |
36 | ||
237fead6 MH |
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 | */ | |
47 | static 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; |
cc18ec3c | 52 | struct path *path; |
237fead6 MH |
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) { | |
cc18ec3c MW |
63 | path = ecryptfs_dentry_to_lower_path(file->f_path.dentry); |
64 | touch_atime(path); | |
237fead6 MH |
65 | } |
66 | return rc; | |
67 | } | |
68 | ||
69 | struct ecryptfs_getdents_callback { | |
5c0ba4e0 | 70 | struct dir_context ctx; |
2de5f059 | 71 | struct dir_context *caller; |
0747fdb2 | 72 | struct super_block *sb; |
237fead6 MH |
73 | int filldir_called; |
74 | int entries_written; | |
75 | }; | |
76 | ||
7d6c7045 | 77 | /* Inspired by generic filldir in fs/readdir.c */ |
237fead6 | 78 | static int |
addd65ad MH |
79 | ecryptfs_filldir(void *dirent, const char *lower_name, int lower_namelen, |
80 | loff_t offset, u64 ino, unsigned int d_type) | |
237fead6 | 81 | { |
237fead6 MH |
82 | struct ecryptfs_getdents_callback *buf = |
83 | (struct ecryptfs_getdents_callback *)dirent; | |
a8f12864 | 84 | size_t name_size; |
addd65ad | 85 | char *name; |
237fead6 | 86 | int rc; |
237fead6 | 87 | |
237fead6 | 88 | buf->filldir_called++; |
addd65ad | 89 | rc = ecryptfs_decode_and_decrypt_filename(&name, &name_size, |
0747fdb2 | 90 | buf->sb, lower_name, |
addd65ad MH |
91 | 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); | |
237fead6 MH |
96 | goto out; |
97 | } | |
2de5f059 AV |
98 | buf->caller->pos = buf->ctx.pos; |
99 | rc = !dir_emit(buf->caller, name, name_size, ino, d_type); | |
addd65ad | 100 | kfree(name); |
2de5f059 | 101 | if (!rc) |
237fead6 MH |
102 | buf->entries_written++; |
103 | out: | |
104 | return rc; | |
105 | } | |
106 | ||
107 | /** | |
108 | * ecryptfs_readdir | |
addd65ad | 109 | * @file: The eCryptfs directory file |
2de5f059 | 110 | * @ctx: The actor to feed the entries to |
237fead6 | 111 | */ |
2de5f059 | 112 | static int ecryptfs_readdir(struct file *file, struct dir_context *ctx) |
237fead6 MH |
113 | { |
114 | int rc; | |
115 | struct file *lower_file; | |
0747fdb2 | 116 | struct inode *inode = file_inode(file); |
2de5f059 AV |
117 | struct ecryptfs_getdents_callback buf = { |
118 | .ctx.actor = ecryptfs_filldir, | |
119 | .caller = ctx, | |
0747fdb2 | 120 | .sb = inode->i_sb, |
2de5f059 | 121 | }; |
237fead6 | 122 | lower_file = ecryptfs_file_to_lower(file); |
2de5f059 | 123 | lower_file->f_pos = ctx->pos; |
5c0ba4e0 | 124 | rc = iterate_dir(lower_file, &buf.ctx); |
2de5f059 | 125 | ctx->pos = buf.ctx.pos; |
7d6c7045 MH |
126 | if (rc < 0) |
127 | goto out; | |
128 | if (buf.filldir_called && !buf.entries_written) | |
129 | goto out; | |
237fead6 | 130 | if (rc >= 0) |
7d6c7045 | 131 | fsstack_copy_attr_atime(inode, |
496ad9aa | 132 | file_inode(lower_file)); |
7d6c7045 | 133 | out: |
237fead6 MH |
134 | return rc; |
135 | } | |
136 | ||
137 | struct kmem_cache *ecryptfs_file_info_cache; | |
138 | ||
e3ccaa97 TH |
139 | static 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; | |
176 | out: | |
177 | mutex_unlock(&crypt_stat->cs_mutex); | |
178 | return rc; | |
179 | } | |
180 | ||
237fead6 MH |
181 | /** |
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 | */ | |
190 | static 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; | |
bd243a4b | 195 | struct dentry *ecryptfs_dentry = file->f_path.dentry; |
237fead6 MH |
196 | /* Private value of ecryptfs_dentry allocated in |
197 | * ecryptfs_lookup() */ | |
237fead6 | 198 | struct ecryptfs_file_info *file_info; |
237fead6 | 199 | |
e77a56dd MH |
200 | 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 | } | |
237fead6 | 211 | /* Released in ecryptfs_release or end of function if failure */ |
c3762229 | 212 | file_info = kmem_cache_zalloc(ecryptfs_file_info_cache, GFP_KERNEL); |
237fead6 MH |
213 | 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 | } | |
237fead6 | 220 | crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat; |
237fead6 | 221 | mutex_lock(&crypt_stat->cs_mutex); |
e2bd99ec | 222 | if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)) { |
237fead6 MH |
223 | ecryptfs_printk(KERN_DEBUG, "Setting flags for stat...\n"); |
224 | /* Policy code enabled in future release */ | |
2ed92554 MH |
225 | crypt_stat->flags |= (ECRYPTFS_POLICY_APPLIED |
226 | | ECRYPTFS_ENCRYPTED); | |
237fead6 MH |
227 | } |
228 | mutex_unlock(&crypt_stat->cs_mutex); | |
3b06b3eb | 229 | rc = ecryptfs_get_lower_file(ecryptfs_dentry, inode); |
27992890 RS |
230 | if (rc) { |
231 | printk(KERN_ERR "%s: Error attempting to initialize " | |
332ab16f | 232 | "the lower file for the dentry with name " |
27992890 RS |
233 | "[%s]; rc = [%d]\n", __func__, |
234 | ecryptfs_dentry->d_name.name, rc); | |
235 | goto out_free; | |
72b55fff | 236 | } |
0abe1169 RS |
237 | if ((ecryptfs_inode_to_private(inode)->lower_file->f_flags & O_ACCMODE) |
238 | == O_RDONLY && (file->f_flags & O_ACCMODE) != O_RDONLY) { | |
e27759d7 | 239 | rc = -EPERM; |
332ab16f | 240 | printk(KERN_WARNING "%s: Lower file is RO; eCryptfs " |
e27759d7 | 241 | "file must hence be opened RO\n", __func__); |
332ab16f | 242 | goto out_put; |
e27759d7 | 243 | } |
2ed92554 MH |
244 | ecryptfs_set_file_lower( |
245 | file, ecryptfs_inode_to_private(inode)->lower_file); | |
237fead6 MH |
246 | if (S_ISDIR(ecryptfs_dentry->d_inode->i_mode)) { |
247 | ecryptfs_printk(KERN_DEBUG, "This is a directory\n"); | |
2f9b12a3 | 248 | mutex_lock(&crypt_stat->cs_mutex); |
e2bd99ec | 249 | crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED); |
2f9b12a3 | 250 | mutex_unlock(&crypt_stat->cs_mutex); |
237fead6 MH |
251 | rc = 0; |
252 | goto out; | |
253 | } | |
e3ccaa97 TH |
254 | rc = read_or_initialize_metadata(ecryptfs_dentry); |
255 | if (rc) | |
256 | goto out_put; | |
888d57bb JP |
257 | 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)); | |
237fead6 | 260 | goto out; |
332ab16f TH |
261 | out_put: |
262 | ecryptfs_put_lower_file(inode); | |
2ed92554 | 263 | out_free: |
237fead6 MH |
264 | kmem_cache_free(ecryptfs_file_info_cache, |
265 | ecryptfs_file_to_private(file)); | |
266 | out: | |
267 | return rc; | |
268 | } | |
269 | ||
270 | static int ecryptfs_flush(struct file *file, fl_owner_t td) | |
271 | { | |
64e6651d TH |
272 | struct file *lower_file = ecryptfs_file_to_lower(file); |
273 | ||
274 | if (lower_file->f_op && lower_file->f_op->flush) { | |
275 | filemap_write_and_wait(file->f_mapping); | |
276 | return lower_file->f_op->flush(lower_file, td); | |
277 | } | |
278 | ||
279 | return 0; | |
237fead6 MH |
280 | } |
281 | ||
282 | static int ecryptfs_release(struct inode *inode, struct file *file) | |
283 | { | |
332ab16f | 284 | ecryptfs_put_lower_file(inode); |
2ed92554 MH |
285 | kmem_cache_free(ecryptfs_file_info_cache, |
286 | ecryptfs_file_to_private(file)); | |
287 | return 0; | |
237fead6 MH |
288 | } |
289 | ||
290 | static int | |
02c24a82 | 291 | ecryptfs_fsync(struct file *file, loff_t start, loff_t end, int datasync) |
237fead6 | 292 | { |
bc5abcf7 TH |
293 | int rc; |
294 | ||
295 | rc = filemap_write_and_wait(file->f_mapping); | |
296 | if (rc) | |
297 | return rc; | |
298 | ||
821f7494 | 299 | return vfs_fsync(ecryptfs_file_to_lower(file), datasync); |
237fead6 MH |
300 | } |
301 | ||
302 | static 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); | |
308 | if (lower_file->f_op && lower_file->f_op->fasync) | |
309 | rc = lower_file->f_op->fasync(fd, lower_file, flag); | |
310 | return rc; | |
311 | } | |
312 | ||
c43f7b8f TH |
313 | static long |
314 | ecryptfs_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg) | |
315 | { | |
316 | struct file *lower_file = NULL; | |
317 | long rc = -ENOTTY; | |
318 | ||
319 | if (ecryptfs_file_to_private(file)) | |
320 | lower_file = ecryptfs_file_to_lower(file); | |
321 | if (lower_file && lower_file->f_op && lower_file->f_op->unlocked_ioctl) | |
322 | rc = lower_file->f_op->unlocked_ioctl(lower_file, cmd, arg); | |
323 | return rc; | |
324 | } | |
325 | ||
326 | #ifdef CONFIG_COMPAT | |
327 | static long | |
328 | ecryptfs_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg) | |
329 | { | |
330 | struct file *lower_file = NULL; | |
331 | long rc = -ENOIOCTLCMD; | |
332 | ||
333 | if (ecryptfs_file_to_private(file)) | |
334 | lower_file = ecryptfs_file_to_lower(file); | |
335 | if (lower_file && lower_file->f_op && lower_file->f_op->compat_ioctl) | |
336 | rc = lower_file->f_op->compat_ioctl(lower_file, cmd, arg); | |
337 | return rc; | |
338 | } | |
339 | #endif | |
237fead6 MH |
340 | |
341 | const struct file_operations ecryptfs_dir_fops = { | |
2de5f059 | 342 | .iterate = ecryptfs_readdir, |
323ef68f | 343 | .read = generic_read_dir, |
c43f7b8f TH |
344 | .unlocked_ioctl = ecryptfs_unlocked_ioctl, |
345 | #ifdef CONFIG_COMPAT | |
346 | .compat_ioctl = ecryptfs_compat_ioctl, | |
347 | #endif | |
237fead6 MH |
348 | .open = ecryptfs_open, |
349 | .flush = ecryptfs_flush, | |
350 | .release = ecryptfs_release, | |
351 | .fsync = ecryptfs_fsync, | |
352 | .fasync = ecryptfs_fasync, | |
e9f6a99c | 353 | .splice_read = generic_file_splice_read, |
6038f373 | 354 | .llseek = default_llseek, |
237fead6 MH |
355 | }; |
356 | ||
357 | const struct file_operations ecryptfs_main_fops = { | |
53a2731f | 358 | .llseek = generic_file_llseek, |
237fead6 MH |
359 | .read = do_sync_read, |
360 | .aio_read = ecryptfs_read_update_atime, | |
361 | .write = do_sync_write, | |
362 | .aio_write = generic_file_aio_write, | |
2de5f059 | 363 | .iterate = ecryptfs_readdir, |
c43f7b8f TH |
364 | .unlocked_ioctl = ecryptfs_unlocked_ioctl, |
365 | #ifdef CONFIG_COMPAT | |
366 | .compat_ioctl = ecryptfs_compat_ioctl, | |
367 | #endif | |
821f7494 | 368 | .mmap = generic_file_mmap, |
237fead6 MH |
369 | .open = ecryptfs_open, |
370 | .flush = ecryptfs_flush, | |
371 | .release = ecryptfs_release, | |
372 | .fsync = ecryptfs_fsync, | |
373 | .fasync = ecryptfs_fasync, | |
e9f6a99c | 374 | .splice_read = generic_file_splice_read, |
237fead6 | 375 | }; |