1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * linux/fs/reiserfs/xattr.c
4 *
5 * Copyright (c) 2002 by Jeff Mahoney, <jeffm@suse.com>
6 *
7 */
8
9 /*
10 * In order to implement EA/ACLs in a clean, backwards compatible manner,
11 * they are implemented as files in a "private" directory.
12 * Each EA is in it's own file, with the directory layout like so (/ is assumed
13 * to be relative to fs root). Inside the /.reiserfs_priv/xattrs directory,
14 * directories named using the capital-hex form of the objectid and
15 * generation number are used. Inside each directory are individual files
16 * named with the name of the extended attribute.
17 *
18 * So, for objectid 12648430, we could have:
19 * /.reiserfs_priv/xattrs/C0FFEE.0/system.posix_acl_access
20 * /.reiserfs_priv/xattrs/C0FFEE.0/system.posix_acl_default
21 * /.reiserfs_priv/xattrs/C0FFEE.0/user.Content-Type
22 * .. or similar.
23 *
24 * The file contents are the text of the EA. The size is known based on the
25 * stat data describing the file.
26 *
27 * In the case of system.posix_acl_access and system.posix_acl_default, since
28 * these are special cases for filesystem ACLs, they are interpreted by the
29 * kernel, in addition, they are negatively and positively cached and attached
30 * to the inode so that unnecessary lookups are avoided.
31 *
32 * Locking works like so:
33 * Directory components (xattr root, xattr dir) are protectd by their i_mutex.
34 * The xattrs themselves are protected by the xattr_sem.
35 */
36
37 #include "reiserfs.h"
38 #include <linux/capability.h>
39 #include <linux/dcache.h>
40 #include <linux/namei.h>
41 #include <linux/errno.h>
42 #include <linux/gfp.h>
43 #include <linux/fs.h>
44 #include <linux/file.h>
45 #include <linux/pagemap.h>
46 #include <linux/xattr.h>
47 #include "xattr.h"
48 #include "acl.h"
49 #include <linux/uaccess.h>
50 #include <net/checksum.h>
51 #include <linux/stat.h>
52 #include <linux/quotaops.h>
53 #include <linux/security.h>
54 #include <linux/posix_acl_xattr.h>
55 #include <linux/xattr.h>
56
57 #define PRIVROOT_NAME ".reiserfs_priv"
58 #define XAROOT_NAME "xattrs"
59
60
61 /*
62 * Helpers for inode ops. We do this so that we don't have all the VFS
63 * overhead and also for proper i_mutex annotation.
64 * dir->i_mutex must be held for all of them.
65 */
66 #ifdef CONFIG_REISERFS_FS_XATTR
67 static int xattr_create(struct inode *dir, struct dentry *dentry, int mode)
68 {
69 BUG_ON(!inode_is_locked(dir));
70 return dir->i_op->create(&nop_mnt_idmap, dir, dentry, mode, true);
71 }
72 #endif
73
74 static int xattr_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
75 {
76 BUG_ON(!inode_is_locked(dir));
77 return dir->i_op->mkdir(&nop_mnt_idmap, dir, dentry, mode);
78 }
79
80 /*
81 * We use I_MUTEX_CHILD here to silence lockdep. It's safe because xattr
82 * mutation ops aren't called during rename or splace, which are the
83 * only other users of I_MUTEX_CHILD. It violates the ordering, but that's
84 * better than allocating another subclass just for this code.
85 */
86 static int xattr_unlink(struct inode *dir, struct dentry *dentry)
87 {
88 int error;
89
90 BUG_ON(!inode_is_locked(dir));
91
92 inode_lock_nested(d_inode(dentry), I_MUTEX_CHILD);
93 error = dir->i_op->unlink(dir, dentry);
94 inode_unlock(d_inode(dentry));
95
96 if (!error)
97 d_delete(dentry);
98 return error;
99 }
100
101 static int xattr_rmdir(struct inode *dir, struct dentry *dentry)
102 {
103 int error;
104
105 BUG_ON(!inode_is_locked(dir));
106
107 inode_lock_nested(d_inode(dentry), I_MUTEX_CHILD);
108 error = dir->i_op->rmdir(dir, dentry);
109 if (!error)
110 d_inode(dentry)->i_flags |= S_DEAD;
111 inode_unlock(d_inode(dentry));
112 if (!error)
113 d_delete(dentry);
114
115 return error;
116 }
117
118 #define xattr_may_create(flags) (!flags || flags & XATTR_CREATE)
119
120 static struct dentry *open_xa_root(struct super_block *sb, int flags)
121 {
122 struct dentry *privroot = REISERFS_SB(sb)->priv_root;
123 struct dentry *xaroot;
124
125 if (d_really_is_negative(privroot))
126 return ERR_PTR(-EOPNOTSUPP);
127
128 inode_lock_nested(d_inode(privroot), I_MUTEX_XATTR);
129
130 xaroot = dget(REISERFS_SB(sb)->xattr_root);
131 if (!xaroot)
132 xaroot = ERR_PTR(-EOPNOTSUPP);
133 else if (d_really_is_negative(xaroot)) {
134 int err = -ENODATA;
135
136 if (xattr_may_create(flags))
137 err = xattr_mkdir(d_inode(privroot), xaroot, 0700);
138 if (err) {
139 dput(xaroot);
140 xaroot = ERR_PTR(err);
141 }
142 }
143
144 inode_unlock(d_inode(privroot));
145 return xaroot;
146 }
147
148 static struct dentry *open_xa_dir(const struct inode *inode, int flags)
149 {
150 struct dentry *xaroot, *xadir;
151 char namebuf[17];
152
153 xaroot = open_xa_root(inode->i_sb, flags);
154 if (IS_ERR(xaroot))
155 return xaroot;
156
157 snprintf(namebuf, sizeof(namebuf), "%X.%X",
158 le32_to_cpu(INODE_PKEY(inode)->k_objectid),
159 inode->i_generation);
160
161 inode_lock_nested(d_inode(xaroot), I_MUTEX_XATTR);
162
163 xadir = lookup_one_len(namebuf, xaroot, strlen(namebuf));
164 if (!IS_ERR(xadir) && d_really_is_negative(xadir)) {
165 int err = -ENODATA;
166
167 if (xattr_may_create(flags))
168 err = xattr_mkdir(d_inode(xaroot), xadir, 0700);
169 if (err) {
170 dput(xadir);
171 xadir = ERR_PTR(err);
172 }
173 }
174
175 inode_unlock(d_inode(xaroot));
176 dput(xaroot);
177 return xadir;
178 }
179
180 /*
181 * The following are side effects of other operations that aren't explicitly
182 * modifying extended attributes. This includes operations such as permissions
183 * or ownership changes, object deletions, etc.
184 */
185 struct reiserfs_dentry_buf {
186 struct dir_context ctx;
187 struct dentry *xadir;
188 int count;
189 int err;
190 struct dentry *dentries[8];
191 };
192
193 static bool
194 fill_with_dentries(struct dir_context *ctx, const char *name, int namelen,
195 loff_t offset, u64 ino, unsigned int d_type)
196 {
197 struct reiserfs_dentry_buf *dbuf =
198 container_of(ctx, struct reiserfs_dentry_buf, ctx);
199 struct dentry *dentry;
200
201 WARN_ON_ONCE(!inode_is_locked(d_inode(dbuf->xadir)));
202
203 if (dbuf->count == ARRAY_SIZE(dbuf->dentries))
204 return false;
205
206 if (name[0] == '.' && (namelen < 2 ||
207 (namelen == 2 && name[1] == '.')))
208 return true;
209
210 dentry = lookup_one_len(name, dbuf->xadir, namelen);
211 if (IS_ERR(dentry)) {
212 dbuf->err = PTR_ERR(dentry);
213 return false;
214 } else if (d_really_is_negative(dentry)) {
215 /* A directory entry exists, but no file? */
216 reiserfs_error(dentry->d_sb, "xattr-20003",
217 "Corrupted directory: xattr %pd listed but "
218 "not found for file %pd.\n",
219 dentry, dbuf->xadir);
220 dput(dentry);
221 dbuf->err = -EIO;
222 return false;
223 }
224
225 dbuf->dentries[dbuf->count++] = dentry;
226 return true;
227 }
228
229 static void
230 cleanup_dentry_buf(struct reiserfs_dentry_buf *buf)
231 {
232 int i;
233
234 for (i = 0; i < buf->count; i++)
235 if (buf->dentries[i])
236 dput(buf->dentries[i]);
237 }
238
239 static int reiserfs_for_each_xattr(struct inode *inode,
240 int (*action)(struct dentry *, void *),
241 void *data)
242 {
243 struct dentry *dir;
244 int i, err = 0;
245 struct reiserfs_dentry_buf buf = {
246 .ctx.actor = fill_with_dentries,
247 };
248
249 /* Skip out, an xattr has no xattrs associated with it */
250 if (IS_PRIVATE(inode) || get_inode_sd_version(inode) == STAT_DATA_V1)
251 return 0;
252
253 dir = open_xa_dir(inode, XATTR_REPLACE);
254 if (IS_ERR(dir)) {
255 err = PTR_ERR(dir);
256 goto out;
257 } else if (d_really_is_negative(dir)) {
258 err = 0;
259 goto out_dir;
260 }
261
262 inode_lock_nested(d_inode(dir), I_MUTEX_XATTR);
263
264 buf.xadir = dir;
265 while (1) {
266 err = reiserfs_readdir_inode(d_inode(dir), &buf.ctx);
267 if (err)
268 break;
269 if (buf.err) {
270 err = buf.err;
271 break;
272 }
273 if (!buf.count)
274 break;
275 for (i = 0; !err && i < buf.count && buf.dentries[i]; i++) {
276 struct dentry *dentry = buf.dentries[i];
277
278 if (!d_is_dir(dentry))
279 err = action(dentry, data);
280
281 dput(dentry);
282 buf.dentries[i] = NULL;
283 }
284 if (err)
285 break;
286 buf.count = 0;
287 }
288 inode_unlock(d_inode(dir));
289
290 cleanup_dentry_buf(&buf);
291
292 if (!err) {
293 /*
294 * We start a transaction here to avoid a ABBA situation
295 * between the xattr root's i_mutex and the journal lock.
296 * This doesn't incur much additional overhead since the
297 * new transaction will just nest inside the
298 * outer transaction.
299 */
300 int blocks = JOURNAL_PER_BALANCE_CNT * 2 + 2 +
301 4 * REISERFS_QUOTA_TRANS_BLOCKS(inode->i_sb);
302 struct reiserfs_transaction_handle th;
303
304 reiserfs_write_lock(inode->i_sb);
305 err = journal_begin(&th, inode->i_sb, blocks);
306 reiserfs_write_unlock(inode->i_sb);
307 if (!err) {
308 int jerror;
309
310 inode_lock_nested(d_inode(dir->d_parent),
311 I_MUTEX_XATTR);
312 err = action(dir, data);
313 reiserfs_write_lock(inode->i_sb);
314 jerror = journal_end(&th);
315 reiserfs_write_unlock(inode->i_sb);
316 inode_unlock(d_inode(dir->d_parent));
317 err = jerror ?: err;
318 }
319 }
320 out_dir:
321 dput(dir);
322 out:
323 /*
324 * -ENODATA: this object doesn't have any xattrs
325 * -EOPNOTSUPP: this file system doesn't have xattrs enabled on disk.
326 * Neither are errors
327 */
328 if (err == -ENODATA || err == -EOPNOTSUPP)
329 err = 0;
330 return err;
331 }
332
333 static int delete_one_xattr(struct dentry *dentry, void *data)
334 {
335 struct inode *dir = d_inode(dentry->d_parent);
336
337 /* This is the xattr dir, handle specially. */
338 if (d_is_dir(dentry))
339 return xattr_rmdir(dir, dentry);
340
341 return xattr_unlink(dir, dentry);
342 }
343
344 static int chown_one_xattr(struct dentry *dentry, void *data)
345 {
346 struct iattr *attrs = data;
347 int ia_valid = attrs->ia_valid;
348 int err;
349
350 /*
351 * We only want the ownership bits. Otherwise, we'll do
352 * things like change a directory to a regular file if
353 * ATTR_MODE is set.
354 */
355 attrs->ia_valid &= (ATTR_UID|ATTR_GID);
356 err = reiserfs_setattr(&nop_mnt_idmap, dentry, attrs);
357 attrs->ia_valid = ia_valid;
358
359 return err;
360 }
361
362 /* No i_mutex, but the inode is unconnected. */
363 int reiserfs_delete_xattrs(struct inode *inode)
364 {
365 int err = reiserfs_for_each_xattr(inode, delete_one_xattr, NULL);
366
367 if (err)
368 reiserfs_warning(inode->i_sb, "jdm-20004",
369 "Couldn't delete all xattrs (%d)\n", err);
370 return err;
371 }
372
373 /* inode->i_mutex: down */
374 int reiserfs_chown_xattrs(struct inode *inode, struct iattr *attrs)
375 {
376 int err = reiserfs_for_each_xattr(inode, chown_one_xattr, attrs);
377
378 if (err)
379 reiserfs_warning(inode->i_sb, "jdm-20007",
380 "Couldn't chown all xattrs (%d)\n", err);
381 return err;
382 }
383
384 #ifdef CONFIG_REISERFS_FS_XATTR
385 /*
386 * Returns a dentry corresponding to a specific extended attribute file
387 * for the inode. If flags allow, the file is created. Otherwise, a
388 * valid or negative dentry, or an error is returned.
389 */
390 static struct dentry *xattr_lookup(struct inode *inode, const char *name,
391 int flags)
392 {
393 struct dentry *xadir, *xafile;
394 int err = 0;
395
396 xadir = open_xa_dir(inode, flags);
397 if (IS_ERR(xadir))
398 return ERR_CAST(xadir);
399
400 inode_lock_nested(d_inode(xadir), I_MUTEX_XATTR);
401 xafile = lookup_one_len(name, xadir, strlen(name));
402 if (IS_ERR(xafile)) {
403 err = PTR_ERR(xafile);
404 goto out;
405 }
406
407 if (d_really_is_positive(xafile) && (flags & XATTR_CREATE))
408 err = -EEXIST;
409
410 if (d_really_is_negative(xafile)) {
411 err = -ENODATA;
412 if (xattr_may_create(flags))
413 err = xattr_create(d_inode(xadir), xafile,
414 0700|S_IFREG);
415 }
416
417 if (err)
418 dput(xafile);
419 out:
420 inode_unlock(d_inode(xadir));
421 dput(xadir);
422 if (err)
423 return ERR_PTR(err);
424 return xafile;
425 }
426
427 /* Internal operations on file data */
428 static inline void reiserfs_put_page(struct page *page)
429 {
430 kunmap(page);
431 put_page(page);
432 }
433
434 static struct page *reiserfs_get_page(struct inode *dir, size_t n)
435 {
436 struct address_space *mapping = dir->i_mapping;
437 struct page *page;
438 /*
439 * We can deadlock if we try to free dentries,
440 * and an unlink/rmdir has just occurred - GFP_NOFS avoids this
441 */
442 mapping_set_gfp_mask(mapping, GFP_NOFS);
443 page = read_mapping_page(mapping, n >> PAGE_SHIFT, NULL);
444 if (!IS_ERR(page))
445 kmap(page);
446 return page;
447 }
448
449 static inline __u32 xattr_hash(const char *msg, int len)
450 {
451 /*
452 * csum_partial() gives different results for little-endian and
453 * big endian hosts. Images created on little-endian hosts and
454 * mounted on big-endian hosts(and vice versa) will see csum mismatches
455 * when trying to fetch xattrs. Treating the hash as __wsum_t would
456 * lower the frequency of mismatch. This is an endianness bug in
457 * reiserfs. The return statement would result in a sparse warning. Do
458 * not fix the sparse warning so as to not hide a reminder of the bug.
459 */
460 return csum_partial(msg, len, 0);
461 }
462
463 int reiserfs_commit_write(struct file *f, struct page *page,
464 unsigned from, unsigned to);
465
466 static void update_ctime(struct inode *inode)
467 {
468 struct timespec64 now = current_time(inode);
469 struct timespec64 ctime = inode_get_ctime(inode);
470
471 if (inode_unhashed(inode) || !inode->i_nlink ||
472 timespec64_equal(&ctime, &now))
473 return;
474
475 inode_set_ctime_to_ts(inode, now);
476 mark_inode_dirty(inode);
477 }
478
479 static int lookup_and_delete_xattr(struct inode *inode, const char *name)
480 {
481 int err = 0;
482 struct dentry *dentry, *xadir;
483
484 xadir = open_xa_dir(inode, XATTR_REPLACE);
485 if (IS_ERR(xadir))
486 return PTR_ERR(xadir);
487
488 inode_lock_nested(d_inode(xadir), I_MUTEX_XATTR);
489 dentry = lookup_one_len(name, xadir, strlen(name));
490 if (IS_ERR(dentry)) {
491 err = PTR_ERR(dentry);
492 goto out_dput;
493 }
494
495 if (d_really_is_positive(dentry)) {
496 err = xattr_unlink(d_inode(xadir), dentry);
497 update_ctime(inode);
498 }
499
500 dput(dentry);
501 out_dput:
502 inode_unlock(d_inode(xadir));
503 dput(xadir);
504 return err;
505 }
506
507
508 /* Generic extended attribute operations that can be used by xa plugins */
509
510 /*
511 * inode->i_mutex: down
512 */
513 int
514 reiserfs_xattr_set_handle(struct reiserfs_transaction_handle *th,
515 struct inode *inode, const char *name,
516 const void *buffer, size_t buffer_size, int flags)
517 {
518 int err = 0;
519 struct dentry *dentry;
520 struct page *page;
521 char *data;
522 size_t file_pos = 0;
523 size_t buffer_pos = 0;
524 size_t new_size;
525 __u32 xahash = 0;
526
527 if (get_inode_sd_version(inode) == STAT_DATA_V1)
528 return -EOPNOTSUPP;
529
530 if (!buffer) {
531 err = lookup_and_delete_xattr(inode, name);
532 return err;
533 }
534
535 dentry = xattr_lookup(inode, name, flags);
536 if (IS_ERR(dentry))
537 return PTR_ERR(dentry);
538
539 down_write(&REISERFS_I(inode)->i_xattr_sem);
540
541 xahash = xattr_hash(buffer, buffer_size);
542 while (buffer_pos < buffer_size || buffer_pos == 0) {
543 size_t chunk;
544 size_t skip = 0;
545 size_t page_offset = (file_pos & (PAGE_SIZE - 1));
546
547 if (buffer_size - buffer_pos > PAGE_SIZE)
548 chunk = PAGE_SIZE;
549 else
550 chunk = buffer_size - buffer_pos;
551
552 page = reiserfs_get_page(d_inode(dentry), file_pos);
553 if (IS_ERR(page)) {
554 err = PTR_ERR(page);
555 goto out_unlock;
556 }
557
558 lock_page(page);
559 data = page_address(page);
560
561 if (file_pos == 0) {
562 struct reiserfs_xattr_header *rxh;
563
564 skip = file_pos = sizeof(struct reiserfs_xattr_header);
565 if (chunk + skip > PAGE_SIZE)
566 chunk = PAGE_SIZE - skip;
567 rxh = (struct reiserfs_xattr_header *)data;
568 rxh->h_magic = cpu_to_le32(REISERFS_XATTR_MAGIC);
569 rxh->h_hash = cpu_to_le32(xahash);
570 }
571
572 reiserfs_write_lock(inode->i_sb);
573 err = __reiserfs_write_begin(page, page_offset, chunk + skip);
574 if (!err) {
575 if (buffer)
576 memcpy(data + skip, buffer + buffer_pos, chunk);
577 err = reiserfs_commit_write(NULL, page, page_offset,
578 page_offset + chunk +
579 skip);
580 }
581 reiserfs_write_unlock(inode->i_sb);
582 unlock_page(page);
583 reiserfs_put_page(page);
584 buffer_pos += chunk;
585 file_pos += chunk;
586 skip = 0;
587 if (err || buffer_size == 0 || !buffer)
588 break;
589 }
590
591 new_size = buffer_size + sizeof(struct reiserfs_xattr_header);
592 if (!err && new_size < i_size_read(d_inode(dentry))) {
593 struct iattr newattrs = {
594 .ia_ctime = current_time(inode),
595 .ia_size = new_size,
596 .ia_valid = ATTR_SIZE | ATTR_CTIME,
597 };
598
599 inode_lock_nested(d_inode(dentry), I_MUTEX_XATTR);
600 inode_dio_wait(d_inode(dentry));
601
602 err = reiserfs_setattr(&nop_mnt_idmap, dentry, &newattrs);
603 inode_unlock(d_inode(dentry));
604 } else
605 update_ctime(inode);
606 out_unlock:
607 up_write(&REISERFS_I(inode)->i_xattr_sem);
608 dput(dentry);
609 return err;
610 }
611
612 /* We need to start a transaction to maintain lock ordering */
613 int reiserfs_xattr_set(struct inode *inode, const char *name,
614 const void *buffer, size_t buffer_size, int flags)
615 {
616
617 struct reiserfs_transaction_handle th;
618 int error, error2;
619 size_t jbegin_count = reiserfs_xattr_nblocks(inode, buffer_size);
620
621 /* Check before we start a transaction and then do nothing. */
622 if (!d_really_is_positive(REISERFS_SB(inode->i_sb)->priv_root))
623 return -EOPNOTSUPP;
624
625 if (!(flags & XATTR_REPLACE))
626 jbegin_count += reiserfs_xattr_jcreate_nblocks(inode);
627
628 reiserfs_write_lock(inode->i_sb);
629 error = journal_begin(&th, inode->i_sb, jbegin_count);
630 reiserfs_write_unlock(inode->i_sb);
631 if (error) {
632 return error;
633 }
634
635 error = reiserfs_xattr_set_handle(&th, inode, name,
636 buffer, buffer_size, flags);
637
638 reiserfs_write_lock(inode->i_sb);
639 error2 = journal_end(&th);
640 reiserfs_write_unlock(inode->i_sb);
641 if (error == 0)
642 error = error2;
643
644 return error;
645 }
646
647 /*
648 * inode->i_mutex: down
649 */
650 int
651 reiserfs_xattr_get(struct inode *inode, const char *name, void *buffer,
652 size_t buffer_size)
653 {
654 ssize_t err = 0;
655 struct dentry *dentry;
656 size_t isize;
657 size_t file_pos = 0;
658 size_t buffer_pos = 0;
659 struct page *page;
660 __u32 hash = 0;
661
662 if (name == NULL)
663 return -EINVAL;
664
665 /*
666 * We can't have xattrs attached to v1 items since they don't have
667 * generation numbers
668 */
669 if (get_inode_sd_version(inode) == STAT_DATA_V1)
670 return -EOPNOTSUPP;
671
672 /*
673 * priv_root needn't be initialized during mount so allow initial
674 * lookups to succeed.
675 */
676 if (!REISERFS_SB(inode->i_sb)->priv_root)
677 return 0;
678
679 dentry = xattr_lookup(inode, name, XATTR_REPLACE);
680 if (IS_ERR(dentry)) {
681 err = PTR_ERR(dentry);
682 goto out;
683 }
684
685 down_read(&REISERFS_I(inode)->i_xattr_sem);
686
687 isize = i_size_read(d_inode(dentry));
688
689 /* Just return the size needed */
690 if (buffer == NULL) {
691 err = isize - sizeof(struct reiserfs_xattr_header);
692 goto out_unlock;
693 }
694
695 if (buffer_size < isize - sizeof(struct reiserfs_xattr_header)) {
696 err = -ERANGE;
697 goto out_unlock;
698 }
699
700 while (file_pos < isize) {
701 size_t chunk;
702 char *data;
703 size_t skip = 0;
704
705 if (isize - file_pos > PAGE_SIZE)
706 chunk = PAGE_SIZE;
707 else
708 chunk = isize - file_pos;
709
710 page = reiserfs_get_page(d_inode(dentry), file_pos);
711 if (IS_ERR(page)) {
712 err = PTR_ERR(page);
713 goto out_unlock;
714 }
715
716 lock_page(page);
717 data = page_address(page);
718 if (file_pos == 0) {
719 struct reiserfs_xattr_header *rxh =
720 (struct reiserfs_xattr_header *)data;
721 skip = file_pos = sizeof(struct reiserfs_xattr_header);
722 chunk -= skip;
723 /* Magic doesn't match up.. */
724 if (rxh->h_magic != cpu_to_le32(REISERFS_XATTR_MAGIC)) {
725 unlock_page(page);
726 reiserfs_put_page(page);
727 reiserfs_warning(inode->i_sb, "jdm-20001",
728 "Invalid magic for xattr (%s) "
729 "associated with %k", name,
730 INODE_PKEY(inode));
731 err = -EIO;
732 goto out_unlock;
733 }
734 hash = le32_to_cpu(rxh->h_hash);
735 }
736 memcpy(buffer + buffer_pos, data + skip, chunk);
737 unlock_page(page);
738 reiserfs_put_page(page);
739 file_pos += chunk;
740 buffer_pos += chunk;
741 skip = 0;
742 }
743 err = isize - sizeof(struct reiserfs_xattr_header);
744
745 if (xattr_hash(buffer, isize - sizeof(struct reiserfs_xattr_header)) !=
746 hash) {
747 reiserfs_warning(inode->i_sb, "jdm-20002",
748 "Invalid hash for xattr (%s) associated "
749 "with %k", name, INODE_PKEY(inode));
750 err = -EIO;
751 }
752
753 out_unlock:
754 up_read(&REISERFS_I(inode)->i_xattr_sem);
755 dput(dentry);
756
757 out:
758 return err;
759 }
760
761 /*
762 * In order to implement different sets of xattr operations for each xattr
763 * prefix with the generic xattr API, a filesystem should create a
764 * null-terminated array of struct xattr_handler (one for each prefix) and
765 * hang a pointer to it off of the s_xattr field of the superblock.
766 *
767 * The generic_fooxattr() functions will use this list to dispatch xattr
768 * operations to the correct xattr_handler.
769 */
770 #define for_each_xattr_handler(handlers, handler) \
771 for ((handler) = *(handlers)++; \
772 (handler) != NULL; \
773 (handler) = *(handlers)++)
774
775 static inline bool reiserfs_posix_acl_list(const char *name,
776 struct dentry *dentry)
777 {
778 return (posix_acl_type(name) >= 0) &&
779 IS_POSIXACL(d_backing_inode(dentry));
780 }
781
782 /* This is the implementation for the xattr plugin infrastructure */
783 static inline bool reiserfs_xattr_list(const struct xattr_handler * const *handlers,
784 const char *name, struct dentry *dentry)
785 {
786 if (handlers) {
787 const struct xattr_handler *xah = NULL;
788
789 for_each_xattr_handler(handlers, xah) {
790 const char *prefix = xattr_prefix(xah);
791
792 if (strncmp(prefix, name, strlen(prefix)))
793 continue;
794
795 if (!xattr_handler_can_list(xah, dentry))
796 return false;
797
798 return true;
799 }
800 }
801
802 return reiserfs_posix_acl_list(name, dentry);
803 }
804
805 struct listxattr_buf {
806 struct dir_context ctx;
807 size_t size;
808 size_t pos;
809 char *buf;
810 struct dentry *dentry;
811 };
812
813 static bool listxattr_filler(struct dir_context *ctx, const char *name,
814 int namelen, loff_t offset, u64 ino,
815 unsigned int d_type)
816 {
817 struct listxattr_buf *b =
818 container_of(ctx, struct listxattr_buf, ctx);
819 size_t size;
820
821 if (name[0] != '.' ||
822 (namelen != 1 && (name[1] != '.' || namelen != 2))) {
823 if (!reiserfs_xattr_list(b->dentry->d_sb->s_xattr, name,
824 b->dentry))
825 return true;
826 size = namelen + 1;
827 if (b->buf) {
828 if (b->pos + size > b->size) {
829 b->pos = -ERANGE;
830 return false;
831 }
832 memcpy(b->buf + b->pos, name, namelen);
833 b->buf[b->pos + namelen] = 0;
834 }
835 b->pos += size;
836 }
837 return true;
838 }
839
840 /*
841 * Inode operation listxattr()
842 *
843 * We totally ignore the generic listxattr here because it would be stupid
844 * not to. Since the xattrs are organized in a directory, we can just
845 * readdir to find them.
846 */
847 ssize_t reiserfs_listxattr(struct dentry * dentry, char *buffer, size_t size)
848 {
849 struct dentry *dir;
850 int err = 0;
851 struct listxattr_buf buf = {
852 .ctx.actor = listxattr_filler,
853 .dentry = dentry,
854 .buf = buffer,
855 .size = buffer ? size : 0,
856 };
857
858 if (d_really_is_negative(dentry))
859 return -EINVAL;
860
861 if (get_inode_sd_version(d_inode(dentry)) == STAT_DATA_V1)
862 return -EOPNOTSUPP;
863
864 dir = open_xa_dir(d_inode(dentry), XATTR_REPLACE);
865 if (IS_ERR(dir)) {
866 err = PTR_ERR(dir);
867 if (err == -ENODATA)
868 err = 0; /* Not an error if there aren't any xattrs */
869 goto out;
870 }
871
872 inode_lock_nested(d_inode(dir), I_MUTEX_XATTR);
873 err = reiserfs_readdir_inode(d_inode(dir), &buf.ctx);
874 inode_unlock(d_inode(dir));
875
876 if (!err)
877 err = buf.pos;
878
879 dput(dir);
880 out:
881 return err;
882 }
883
884 static int create_privroot(struct dentry *dentry)
885 {
886 int err;
887 struct inode *inode = d_inode(dentry->d_parent);
888
889 WARN_ON_ONCE(!inode_is_locked(inode));
890
891 err = xattr_mkdir(inode, dentry, 0700);
892 if (err || d_really_is_negative(dentry)) {
893 reiserfs_warning(dentry->d_sb, "jdm-20006",
894 "xattrs/ACLs enabled and couldn't "
895 "find/create .reiserfs_priv. "
896 "Failing mount.");
897 return -EOPNOTSUPP;
898 }
899
900 reiserfs_init_priv_inode(d_inode(dentry));
901 reiserfs_info(dentry->d_sb, "Created %s - reserved for xattr "
902 "storage.\n", PRIVROOT_NAME);
903
904 return 0;
905 }
906
907 #else
908 int __init reiserfs_xattr_register_handlers(void) { return 0; }
909 void reiserfs_xattr_unregister_handlers(void) {}
910 static int create_privroot(struct dentry *dentry) { return 0; }
911 #endif
912
913 /* Actual operations that are exported to VFS-land */
914 const struct xattr_handler * const reiserfs_xattr_handlers[] = {
915 #ifdef CONFIG_REISERFS_FS_XATTR
916 &reiserfs_xattr_user_handler,
917 &reiserfs_xattr_trusted_handler,
918 #endif
919 #ifdef CONFIG_REISERFS_FS_SECURITY
920 &reiserfs_xattr_security_handler,
921 #endif
922 NULL
923 };
924
925 static int xattr_mount_check(struct super_block *s)
926 {
927 /*
928 * We need generation numbers to ensure that the oid mapping is correct
929 * v3.5 filesystems don't have them.
930 */
931 if (old_format_only(s)) {
932 if (reiserfs_xattrs_optional(s)) {
933 /*
934 * Old format filesystem, but optional xattrs have
935 * been enabled. Error out.
936 */
937 reiserfs_warning(s, "jdm-2005",
938 "xattrs/ACLs not supported "
939 "on pre-v3.6 format filesystems. "
940 "Failing mount.");
941 return -EOPNOTSUPP;
942 }
943 }
944
945 return 0;
946 }
947
948 int reiserfs_permission(struct mnt_idmap *idmap, struct inode *inode,
949 int mask)
950 {
951 /*
952 * We don't do permission checks on the internal objects.
953 * Permissions are determined by the "owning" object.
954 */
955 if (IS_PRIVATE(inode))
956 return 0;
957
958 return generic_permission(&nop_mnt_idmap, inode, mask);
959 }
960
961 static int xattr_hide_revalidate(struct dentry *dentry, unsigned int flags)
962 {
963 return -EPERM;
964 }
965
966 static const struct dentry_operations xattr_lookup_poison_ops = {
967 .d_revalidate = xattr_hide_revalidate,
968 };
969
970 int reiserfs_lookup_privroot(struct super_block *s)
971 {
972 struct dentry *dentry;
973 int err = 0;
974
975 /* If we don't have the privroot located yet - go find it */
976 inode_lock(d_inode(s->s_root));
977 dentry = lookup_one_len(PRIVROOT_NAME, s->s_root,
978 strlen(PRIVROOT_NAME));
979 if (!IS_ERR(dentry)) {
980 REISERFS_SB(s)->priv_root = dentry;
981 d_set_d_op(dentry, &xattr_lookup_poison_ops);
982 if (d_really_is_positive(dentry))
983 reiserfs_init_priv_inode(d_inode(dentry));
984 } else
985 err = PTR_ERR(dentry);
986 inode_unlock(d_inode(s->s_root));
987
988 return err;
989 }
990
991 /*
992 * We need to take a copy of the mount flags since things like
993 * SB_RDONLY don't get set until *after* we're called.
994 * mount_flags != mount_options
995 */
996 int reiserfs_xattr_init(struct super_block *s, int mount_flags)
997 {
998 int err = 0;
999 struct dentry *privroot = REISERFS_SB(s)->priv_root;
1000
1001 err = xattr_mount_check(s);
1002 if (err)
1003 goto error;
1004
1005 if (d_really_is_negative(privroot) && !(mount_flags & SB_RDONLY)) {
1006 inode_lock(d_inode(s->s_root));
1007 err = create_privroot(REISERFS_SB(s)->priv_root);
1008 inode_unlock(d_inode(s->s_root));
1009 }
1010
1011 if (d_really_is_positive(privroot)) {
1012 inode_lock(d_inode(privroot));
1013 if (!REISERFS_SB(s)->xattr_root) {
1014 struct dentry *dentry;
1015
1016 dentry = lookup_one_len(XAROOT_NAME, privroot,
1017 strlen(XAROOT_NAME));
1018 if (!IS_ERR(dentry))
1019 REISERFS_SB(s)->xattr_root = dentry;
1020 else
1021 err = PTR_ERR(dentry);
1022 }
1023 inode_unlock(d_inode(privroot));
1024 }
1025
1026 error:
1027 if (err) {
1028 clear_bit(REISERFS_XATTRS_USER, &REISERFS_SB(s)->s_mount_opt);
1029 clear_bit(REISERFS_POSIXACL, &REISERFS_SB(s)->s_mount_opt);
1030 }
1031
1032 /* The super_block SB_POSIXACL must mirror the (no)acl mount option. */
1033 if (reiserfs_posixacl(s))
1034 s->s_flags |= SB_POSIXACL;
1035 else
1036 s->s_flags &= ~SB_POSIXACL;
1037
1038 return err;
1039 }
1040
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