Commit | Line | Data |
---|---|---|
e9be9d5e MS |
1 | /* |
2 | * | |
3 | * Copyright (C) 2011 Novell Inc. | |
4 | * | |
5 | * This program is free software; you can redistribute it and/or modify it | |
6 | * under the terms of the GNU General Public License version 2 as published by | |
7 | * the Free Software Foundation. | |
8 | */ | |
9 | ||
fb5bb2c3 | 10 | #include <linux/module.h> |
e9be9d5e MS |
11 | #include <linux/fs.h> |
12 | #include <linux/slab.h> | |
13 | #include <linux/file.h> | |
14 | #include <linux/splice.h> | |
15 | #include <linux/xattr.h> | |
16 | #include <linux/security.h> | |
17 | #include <linux/uaccess.h> | |
174cd4b1 | 18 | #include <linux/sched/signal.h> |
5b825c3a | 19 | #include <linux/cred.h> |
e9be9d5e | 20 | #include <linux/namei.h> |
fb5bb2c3 DH |
21 | #include <linux/fdtable.h> |
22 | #include <linux/ratelimit.h> | |
e9be9d5e | 23 | #include "overlayfs.h" |
d8514d8e | 24 | #include "ovl_entry.h" |
e9be9d5e MS |
25 | |
26 | #define OVL_COPY_UP_CHUNK_SIZE (1 << 20) | |
27 | ||
fb5bb2c3 DH |
28 | static bool __read_mostly ovl_check_copy_up; |
29 | module_param_named(check_copy_up, ovl_check_copy_up, bool, | |
30 | S_IWUSR | S_IRUGO); | |
31 | MODULE_PARM_DESC(ovl_check_copy_up, | |
32 | "Warn on copy-up when causing process also has a R/O fd open"); | |
33 | ||
34 | static int ovl_check_fd(const void *data, struct file *f, unsigned int fd) | |
35 | { | |
36 | const struct dentry *dentry = data; | |
37 | ||
45063097 | 38 | if (file_inode(f) == d_inode(dentry)) |
fb5bb2c3 DH |
39 | pr_warn_ratelimited("overlayfs: Warning: Copying up %pD, but open R/O on fd %u which will cease to be coherent [pid=%d %s]\n", |
40 | f, fd, current->pid, current->comm); | |
41 | return 0; | |
42 | } | |
43 | ||
44 | /* | |
45 | * Check the fds open by this process and warn if something like the following | |
46 | * scenario is about to occur: | |
47 | * | |
48 | * fd1 = open("foo", O_RDONLY); | |
49 | * fd2 = open("foo", O_RDWR); | |
50 | */ | |
51 | static void ovl_do_check_copy_up(struct dentry *dentry) | |
52 | { | |
53 | if (ovl_check_copy_up) | |
54 | iterate_fd(current->files, 0, ovl_check_fd, dentry); | |
55 | } | |
56 | ||
e9be9d5e MS |
57 | int ovl_copy_xattr(struct dentry *old, struct dentry *new) |
58 | { | |
e4ad29fa VC |
59 | ssize_t list_size, size, value_size = 0; |
60 | char *buf, *name, *value = NULL; | |
61 | int uninitialized_var(error); | |
8b326c61 | 62 | size_t slen; |
e9be9d5e | 63 | |
5d6c3191 AG |
64 | if (!(old->d_inode->i_opflags & IOP_XATTR) || |
65 | !(new->d_inode->i_opflags & IOP_XATTR)) | |
e9be9d5e MS |
66 | return 0; |
67 | ||
68 | list_size = vfs_listxattr(old, NULL, 0); | |
69 | if (list_size <= 0) { | |
70 | if (list_size == -EOPNOTSUPP) | |
71 | return 0; | |
72 | return list_size; | |
73 | } | |
74 | ||
75 | buf = kzalloc(list_size, GFP_KERNEL); | |
76 | if (!buf) | |
77 | return -ENOMEM; | |
78 | ||
e9be9d5e MS |
79 | list_size = vfs_listxattr(old, buf, list_size); |
80 | if (list_size <= 0) { | |
81 | error = list_size; | |
e4ad29fa | 82 | goto out; |
e9be9d5e MS |
83 | } |
84 | ||
8b326c61 MS |
85 | for (name = buf; list_size; name += slen) { |
86 | slen = strnlen(name, list_size) + 1; | |
87 | ||
88 | /* underlying fs providing us with an broken xattr list? */ | |
89 | if (WARN_ON(slen > list_size)) { | |
90 | error = -EIO; | |
91 | break; | |
92 | } | |
93 | list_size -= slen; | |
94 | ||
0956254a MS |
95 | if (ovl_is_private_xattr(name)) |
96 | continue; | |
e4ad29fa VC |
97 | retry: |
98 | size = vfs_getxattr(old, name, value, value_size); | |
99 | if (size == -ERANGE) | |
100 | size = vfs_getxattr(old, name, NULL, 0); | |
101 | ||
97daf8b9 | 102 | if (size < 0) { |
e9be9d5e | 103 | error = size; |
e4ad29fa | 104 | break; |
e9be9d5e | 105 | } |
e4ad29fa VC |
106 | |
107 | if (size > value_size) { | |
108 | void *new; | |
109 | ||
110 | new = krealloc(value, size, GFP_KERNEL); | |
111 | if (!new) { | |
112 | error = -ENOMEM; | |
113 | break; | |
114 | } | |
115 | value = new; | |
116 | value_size = size; | |
117 | goto retry; | |
118 | } | |
119 | ||
121ab822 VG |
120 | error = security_inode_copy_up_xattr(name); |
121 | if (error < 0 && error != -EOPNOTSUPP) | |
122 | break; | |
123 | if (error == 1) { | |
124 | error = 0; | |
125 | continue; /* Discard */ | |
126 | } | |
e9be9d5e MS |
127 | error = vfs_setxattr(new, name, value, size, 0); |
128 | if (error) | |
e4ad29fa | 129 | break; |
e9be9d5e | 130 | } |
e9be9d5e MS |
131 | kfree(value); |
132 | out: | |
133 | kfree(buf); | |
134 | return error; | |
135 | } | |
136 | ||
137 | static int ovl_copy_up_data(struct path *old, struct path *new, loff_t len) | |
138 | { | |
139 | struct file *old_file; | |
140 | struct file *new_file; | |
141 | loff_t old_pos = 0; | |
142 | loff_t new_pos = 0; | |
143 | int error = 0; | |
144 | ||
145 | if (len == 0) | |
146 | return 0; | |
147 | ||
0480334f | 148 | old_file = ovl_path_open(old, O_LARGEFILE | O_RDONLY); |
e9be9d5e MS |
149 | if (IS_ERR(old_file)) |
150 | return PTR_ERR(old_file); | |
151 | ||
0480334f | 152 | new_file = ovl_path_open(new, O_LARGEFILE | O_WRONLY); |
e9be9d5e MS |
153 | if (IS_ERR(new_file)) { |
154 | error = PTR_ERR(new_file); | |
155 | goto out_fput; | |
156 | } | |
157 | ||
2ea98466 AG |
158 | /* Try to use clone_file_range to clone up within the same fs */ |
159 | error = vfs_clone_file_range(old_file, 0, new_file, 0, len); | |
160 | if (!error) | |
161 | goto out; | |
162 | /* Couldn't clone, so now we try to copy the data */ | |
163 | error = 0; | |
164 | ||
e9be9d5e MS |
165 | /* FIXME: copy up sparse files efficiently */ |
166 | while (len) { | |
167 | size_t this_len = OVL_COPY_UP_CHUNK_SIZE; | |
168 | long bytes; | |
169 | ||
170 | if (len < this_len) | |
171 | this_len = len; | |
172 | ||
173 | if (signal_pending_state(TASK_KILLABLE, current)) { | |
174 | error = -EINTR; | |
175 | break; | |
176 | } | |
177 | ||
178 | bytes = do_splice_direct(old_file, &old_pos, | |
179 | new_file, &new_pos, | |
180 | this_len, SPLICE_F_MOVE); | |
181 | if (bytes <= 0) { | |
182 | error = bytes; | |
183 | break; | |
184 | } | |
185 | WARN_ON(old_pos != new_pos); | |
186 | ||
187 | len -= bytes; | |
188 | } | |
2ea98466 | 189 | out: |
641089c1 MS |
190 | if (!error) |
191 | error = vfs_fsync(new_file, 0); | |
e9be9d5e MS |
192 | fput(new_file); |
193 | out_fput: | |
194 | fput(old_file); | |
195 | return error; | |
196 | } | |
197 | ||
e9be9d5e MS |
198 | static int ovl_set_timestamps(struct dentry *upperdentry, struct kstat *stat) |
199 | { | |
200 | struct iattr attr = { | |
201 | .ia_valid = | |
202 | ATTR_ATIME | ATTR_MTIME | ATTR_ATIME_SET | ATTR_MTIME_SET, | |
203 | .ia_atime = stat->atime, | |
204 | .ia_mtime = stat->mtime, | |
205 | }; | |
206 | ||
207 | return notify_change(upperdentry, &attr, NULL); | |
208 | } | |
209 | ||
210 | int ovl_set_attr(struct dentry *upperdentry, struct kstat *stat) | |
211 | { | |
212 | int err = 0; | |
213 | ||
214 | if (!S_ISLNK(stat->mode)) { | |
215 | struct iattr attr = { | |
216 | .ia_valid = ATTR_MODE, | |
217 | .ia_mode = stat->mode, | |
218 | }; | |
219 | err = notify_change(upperdentry, &attr, NULL); | |
220 | } | |
221 | if (!err) { | |
222 | struct iattr attr = { | |
223 | .ia_valid = ATTR_UID | ATTR_GID, | |
224 | .ia_uid = stat->uid, | |
225 | .ia_gid = stat->gid, | |
226 | }; | |
227 | err = notify_change(upperdentry, &attr, NULL); | |
228 | } | |
229 | if (!err) | |
230 | ovl_set_timestamps(upperdentry, stat); | |
231 | ||
232 | return err; | |
e9be9d5e MS |
233 | } |
234 | ||
235 | static int ovl_copy_up_locked(struct dentry *workdir, struct dentry *upperdir, | |
236 | struct dentry *dentry, struct path *lowerpath, | |
42f269b9 | 237 | struct kstat *stat, const char *link, |
d8514d8e | 238 | struct kstat *pstat, bool tmpfile) |
e9be9d5e MS |
239 | { |
240 | struct inode *wdir = workdir->d_inode; | |
241 | struct inode *udir = upperdir->d_inode; | |
242 | struct dentry *newdentry = NULL; | |
243 | struct dentry *upper = NULL; | |
42f269b9 | 244 | struct dentry *temp = NULL; |
e9be9d5e | 245 | int err; |
d8ad8b49 VG |
246 | const struct cred *old_creds = NULL; |
247 | struct cred *new_creds = NULL; | |
32a3d848 AV |
248 | struct cattr cattr = { |
249 | /* Can't properly set mode on creation because of the umask */ | |
250 | .mode = stat->mode & S_IFMT, | |
251 | .rdev = stat->rdev, | |
252 | .link = link | |
253 | }; | |
e9be9d5e | 254 | |
e9be9d5e MS |
255 | upper = lookup_one_len(dentry->d_name.name, upperdir, |
256 | dentry->d_name.len); | |
257 | err = PTR_ERR(upper); | |
258 | if (IS_ERR(upper)) | |
42f269b9 | 259 | goto out; |
e9be9d5e | 260 | |
d8ad8b49 VG |
261 | err = security_inode_copy_up(dentry, &new_creds); |
262 | if (err < 0) | |
42f269b9 | 263 | goto out1; |
d8ad8b49 VG |
264 | |
265 | if (new_creds) | |
266 | old_creds = override_creds(new_creds); | |
267 | ||
d8514d8e AG |
268 | if (tmpfile) |
269 | temp = ovl_do_tmpfile(upperdir, stat->mode); | |
270 | else | |
271 | temp = ovl_lookup_temp(workdir, dentry); | |
42f269b9 AG |
272 | err = PTR_ERR(temp); |
273 | if (IS_ERR(temp)) | |
274 | goto out1; | |
275 | ||
d8514d8e AG |
276 | err = 0; |
277 | if (!tmpfile) | |
278 | err = ovl_create_real(wdir, temp, &cattr, NULL, true); | |
d8ad8b49 VG |
279 | |
280 | if (new_creds) { | |
281 | revert_creds(old_creds); | |
282 | put_cred(new_creds); | |
283 | } | |
284 | ||
e9be9d5e MS |
285 | if (err) |
286 | goto out2; | |
287 | ||
288 | if (S_ISREG(stat->mode)) { | |
289 | struct path upperpath; | |
f134f244 | 290 | |
e9be9d5e MS |
291 | ovl_path_upper(dentry, &upperpath); |
292 | BUG_ON(upperpath.dentry != NULL); | |
42f269b9 | 293 | upperpath.dentry = temp; |
e9be9d5e | 294 | |
01ad3eb8 AG |
295 | if (tmpfile) { |
296 | inode_unlock(udir); | |
297 | err = ovl_copy_up_data(lowerpath, &upperpath, | |
298 | stat->size); | |
299 | inode_lock_nested(udir, I_MUTEX_PARENT); | |
300 | } else { | |
301 | err = ovl_copy_up_data(lowerpath, &upperpath, | |
302 | stat->size); | |
303 | } | |
e9be9d5e | 304 | |
e9be9d5e MS |
305 | if (err) |
306 | goto out_cleanup; | |
307 | } | |
308 | ||
42f269b9 | 309 | err = ovl_copy_xattr(lowerpath->dentry, temp); |
e9be9d5e MS |
310 | if (err) |
311 | goto out_cleanup; | |
312 | ||
42f269b9 AG |
313 | inode_lock(temp->d_inode); |
314 | err = ovl_set_attr(temp, stat); | |
315 | inode_unlock(temp->d_inode); | |
e9be9d5e MS |
316 | if (err) |
317 | goto out_cleanup; | |
318 | ||
d8514d8e AG |
319 | if (tmpfile) |
320 | err = ovl_do_link(temp, udir, upper, true); | |
321 | else | |
322 | err = ovl_do_rename(wdir, temp, udir, upper, 0); | |
e9be9d5e MS |
323 | if (err) |
324 | goto out_cleanup; | |
325 | ||
d8514d8e | 326 | newdentry = dget(tmpfile ? upper : temp); |
e9be9d5e | 327 | ovl_dentry_update(dentry, newdentry); |
39b681f8 | 328 | ovl_inode_update(d_inode(dentry), d_inode(newdentry)); |
42f269b9 AG |
329 | |
330 | /* Restore timestamps on parent (best effort) */ | |
331 | ovl_set_timestamps(upperdir, pstat); | |
e9be9d5e | 332 | out2: |
42f269b9 | 333 | dput(temp); |
e9be9d5e | 334 | out1: |
42f269b9 | 335 | dput(upper); |
e9be9d5e MS |
336 | out: |
337 | return err; | |
338 | ||
339 | out_cleanup: | |
d8514d8e AG |
340 | if (!tmpfile) |
341 | ovl_cleanup(wdir, temp); | |
ab79efab | 342 | goto out2; |
e9be9d5e MS |
343 | } |
344 | ||
345 | /* | |
346 | * Copy up a single dentry | |
347 | * | |
a6c60655 MS |
348 | * All renames start with copy up of source if necessary. The actual |
349 | * rename will only proceed once the copy up was successful. Copy up uses | |
350 | * upper parent i_mutex for exclusion. Since rename can change d_parent it | |
351 | * is possible that the copy up will lock the old parent. At that point | |
352 | * the file will have already been copied up anyway. | |
e9be9d5e | 353 | */ |
9aba6521 AG |
354 | static int ovl_copy_up_one(struct dentry *parent, struct dentry *dentry, |
355 | struct path *lowerpath, struct kstat *stat) | |
e9be9d5e | 356 | { |
7764235b | 357 | DEFINE_DELAYED_CALL(done); |
e9be9d5e MS |
358 | struct dentry *workdir = ovl_workdir(dentry); |
359 | int err; | |
360 | struct kstat pstat; | |
361 | struct path parentpath; | |
7764235b | 362 | struct dentry *lowerdentry = lowerpath->dentry; |
e9be9d5e | 363 | struct dentry *upperdir; |
7764235b | 364 | const char *link = NULL; |
d8514d8e | 365 | struct ovl_fs *ofs = dentry->d_sb->s_fs_info; |
e9be9d5e | 366 | |
cc6f67bc MS |
367 | if (WARN_ON(!workdir)) |
368 | return -EROFS; | |
369 | ||
7764235b | 370 | ovl_do_check_copy_up(lowerdentry); |
fb5bb2c3 | 371 | |
e9be9d5e MS |
372 | ovl_path_upper(parent, &parentpath); |
373 | upperdir = parentpath.dentry; | |
374 | ||
a528d35e DH |
375 | err = vfs_getattr(&parentpath, &pstat, |
376 | STATX_ATIME | STATX_MTIME, AT_STATX_SYNC_AS_STAT); | |
e9be9d5e MS |
377 | if (err) |
378 | return err; | |
379 | ||
380 | if (S_ISLNK(stat->mode)) { | |
7764235b | 381 | link = vfs_get_link(lowerdentry, &done); |
e9be9d5e MS |
382 | if (IS_ERR(link)) |
383 | return PTR_ERR(link); | |
384 | } | |
385 | ||
01ad3eb8 AG |
386 | /* Should we copyup with O_TMPFILE or with workdir? */ |
387 | if (S_ISREG(stat->mode) && ofs->tmpfile) { | |
388 | err = ovl_copy_up_start(dentry); | |
389 | /* err < 0: interrupted, err > 0: raced with another copy-up */ | |
390 | if (unlikely(err)) { | |
391 | pr_debug("ovl_copy_up_start(%pd2) = %i\n", dentry, err); | |
392 | if (err > 0) | |
393 | err = 0; | |
394 | goto out_done; | |
395 | } | |
396 | ||
397 | inode_lock_nested(upperdir->d_inode, I_MUTEX_PARENT); | |
398 | err = ovl_copy_up_locked(workdir, upperdir, dentry, lowerpath, | |
399 | stat, link, &pstat, true); | |
400 | inode_unlock(upperdir->d_inode); | |
401 | ovl_copy_up_end(dentry); | |
402 | goto out_done; | |
403 | } | |
404 | ||
e9be9d5e MS |
405 | err = -EIO; |
406 | if (lock_rename(workdir, upperdir) != NULL) { | |
407 | pr_err("overlayfs: failed to lock workdir+upperdir\n"); | |
408 | goto out_unlock; | |
409 | } | |
a6c60655 | 410 | if (ovl_dentry_upper(dentry)) { |
0f7ff2da | 411 | /* Raced with another copy-up? Nothing to do, then... */ |
e9be9d5e | 412 | err = 0; |
0f7ff2da | 413 | goto out_unlock; |
e9be9d5e MS |
414 | } |
415 | ||
416 | err = ovl_copy_up_locked(workdir, upperdir, dentry, lowerpath, | |
01ad3eb8 | 417 | stat, link, &pstat, false); |
e9be9d5e MS |
418 | out_unlock: |
419 | unlock_rename(workdir, upperdir); | |
01ad3eb8 | 420 | out_done: |
7764235b | 421 | do_delayed_call(&done); |
e9be9d5e MS |
422 | |
423 | return err; | |
424 | } | |
425 | ||
9aba6521 | 426 | int ovl_copy_up_flags(struct dentry *dentry, int flags) |
e9be9d5e | 427 | { |
8eac98b8 VG |
428 | int err = 0; |
429 | const struct cred *old_cred = ovl_override_creds(dentry->d_sb); | |
e9be9d5e | 430 | |
e9be9d5e MS |
431 | while (!err) { |
432 | struct dentry *next; | |
433 | struct dentry *parent; | |
434 | struct path lowerpath; | |
435 | struct kstat stat; | |
436 | enum ovl_path_type type = ovl_path_type(dentry); | |
437 | ||
1afaba1e | 438 | if (OVL_TYPE_UPPER(type)) |
e9be9d5e MS |
439 | break; |
440 | ||
441 | next = dget(dentry); | |
442 | /* find the topmost dentry not yet copied up */ | |
443 | for (;;) { | |
444 | parent = dget_parent(next); | |
445 | ||
446 | type = ovl_path_type(parent); | |
1afaba1e | 447 | if (OVL_TYPE_UPPER(type)) |
e9be9d5e MS |
448 | break; |
449 | ||
450 | dput(next); | |
451 | next = parent; | |
452 | } | |
453 | ||
454 | ovl_path_lower(next, &lowerpath); | |
a528d35e DH |
455 | err = vfs_getattr(&lowerpath, &stat, |
456 | STATX_BASIC_STATS, AT_STATX_SYNC_AS_STAT); | |
9aba6521 AG |
457 | /* maybe truncate regular file. this has no effect on dirs */ |
458 | if (flags & O_TRUNC) | |
459 | stat.size = 0; | |
e9be9d5e | 460 | if (!err) |
0f7ff2da | 461 | err = ovl_copy_up_one(parent, next, &lowerpath, &stat); |
e9be9d5e MS |
462 | |
463 | dput(parent); | |
464 | dput(next); | |
465 | } | |
8eac98b8 | 466 | revert_creds(old_cred); |
e9be9d5e MS |
467 | |
468 | return err; | |
469 | } | |
9aba6521 AG |
470 | |
471 | int ovl_copy_up(struct dentry *dentry) | |
472 | { | |
473 | return ovl_copy_up_flags(dentry, 0); | |
474 | } |