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2023-12-11 072de836f53be56a70cecf70b43ae43b7ce17376 
 kernel/fs/configfs/dir.c
....@@ -1,22 +1,8 @@
1
+// SPDX-License-Identifier: GPL-2.0-or-later
12 /* -*- mode: c; c-basic-offset: 8; -*-
23  * vim: noexpandtab sw=8 ts=8 sts=0:
34  *
45  * dir.c - Operations for configfs directories.
5
- *
6
- * This program is free software; you can redistribute it and/or
7
- * modify it under the terms of the GNU General Public
8
- * License as published by the Free Software Foundation; either
9
- * version 2 of the License, or (at your option) any later version.
10
- *
11
- * This program is distributed in the hope that it will be useful,
12
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
13
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
14
- * General Public License for more details.
15
- *
16
- * You should have received a copy of the GNU General Public
17
- * License along with this program; if not, write to the
18
- * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
19
- * Boston, MA 021110-1307, USA.
206  *
217  * Based on sysfs:
228  * 	sysfs is Copyright (C) 2001, 2002, 2003 Patrick Mochel
....@@ -27,6 +13,7 @@
2713 #undef DEBUG
2814 
2915 #include <linux/fs.h>
16
+#include <linux/fsnotify.h>
3017 #include <linux/mount.h>
3118 #include <linux/module.h>
3219 #include <linux/slab.h>
....@@ -35,7 +22,6 @@
3522 #include <linux/configfs.h>
3623 #include "configfs_internal.h"
3724 
38
-DECLARE_RWSEM(configfs_rename_sem);
3925 /*
4026  * Protects mutations of configfs_dirent linkage together with proper i_mutex
4127  * Also protects mutations of symlinks linkage to target configfs_dirent
....@@ -212,7 +198,6 @@
212198 		return ERR_PTR(-ENOMEM);
213199 
214200 	atomic_set(&sd->s_count, 1);
215
-	INIT_LIST_HEAD(&sd->s_links);
216201 	INIT_LIST_HEAD(&sd->s_children);
217202 	sd->s_element = element;
218203 	sd->s_type = type;
....@@ -274,30 +259,16 @@
274259 	return 0;
275260 }
276261 
277
-static void init_dir(struct inode * inode)
262
+static void configfs_remove_dirent(struct dentry *dentry)
278263 {
279
-	inode->i_op = &configfs_dir_inode_operations;
280
-	inode->i_fop = &configfs_dir_operations;
264
+	struct configfs_dirent *sd = dentry->d_fsdata;
281265 
282
-	/* directory inodes start off with i_nlink == 2 (for "." entry) */
283
-	inc_nlink(inode);
284
-}
285
-
286
-static void configfs_init_file(struct inode * inode)
287
-{
288
-	inode->i_size = PAGE_SIZE;
289
-	inode->i_fop = &configfs_file_operations;
290
-}
291
-
292
-static void configfs_init_bin_file(struct inode *inode)
293
-{
294
-	inode->i_size = 0;
295
-	inode->i_fop = &configfs_bin_file_operations;
296
-}
297
-
298
-static void init_symlink(struct inode * inode)
299
-{
300
-	inode->i_op = &configfs_symlink_inode_operations;
266
+	if (!sd)
267
+		return;
268
+	spin_lock(&configfs_dirent_lock);
269
+	list_del_init(&sd->s_sibling);
270
+	spin_unlock(&configfs_dirent_lock);
271
+	configfs_put(sd);
301272 }
302273 
303274 /**
....@@ -315,6 +286,7 @@
315286 	int error;
316287 	umode_t mode = S_IFDIR| S_IRWXU | S_IRUGO | S_IXUGO;
317288 	struct dentry *p = dentry->d_parent;
289
+	struct inode *inode;
318290 
319291 	BUG_ON(!item);
320292 
....@@ -329,20 +301,24 @@
329301 		return error;
330302 
331303 	configfs_set_dir_dirent_depth(p->d_fsdata, dentry->d_fsdata);
332
-	error = configfs_create(dentry, mode, init_dir);
333
-	if (!error) {
334
-		inc_nlink(d_inode(p));
335
-		item->ci_dentry = dentry;
336
-	} else {
337
-		struct configfs_dirent *sd = dentry->d_fsdata;
338
-		if (sd) {
339
-			spin_lock(&configfs_dirent_lock);
340
-			list_del_init(&sd->s_sibling);
341
-			spin_unlock(&configfs_dirent_lock);
342
-			configfs_put(sd);
343
-		}
344
-	}
345
-	return error;
304
+	inode = configfs_create(dentry, mode);
305
+	if (IS_ERR(inode))
306
+		goto out_remove;
307
+
308
+	inode->i_op = &configfs_dir_inode_operations;
309
+	inode->i_fop = &configfs_dir_operations;
310
+	/* directory inodes start off with i_nlink == 2 (for "." entry) */
311
+	inc_nlink(inode);
312
+	d_instantiate(dentry, inode);
313
+	/* already hashed */
314
+	dget(dentry);  /* pin directory dentries in core */
315
+	inc_nlink(d_inode(p));
316
+	item->ci_dentry = dentry;
317
+	return 0;
318
+
319
+out_remove:
320
+	configfs_remove_dirent(dentry);
321
+	return PTR_ERR(inode);
346322 }
347323 
348324 /*
....@@ -383,41 +359,40 @@
383359 	return ret;
384360 }
385361 
386
-int configfs_create_link(struct configfs_symlink *sl,
387
-			 struct dentry *parent,
388
-			 struct dentry *dentry)
362
+int configfs_create_link(struct configfs_dirent *target, struct dentry *parent,
363
+		struct dentry *dentry, char *body)
389364 {
390365 	int err = 0;
391366 	umode_t mode = S_IFLNK | S_IRWXUGO;
392367 	struct configfs_dirent *p = parent->d_fsdata;
368
+	struct inode *inode;
393369 
394
-	err = configfs_make_dirent(p, dentry, sl, mode,
395
-				   CONFIGFS_ITEM_LINK, p->s_frag);
396
-	if (!err) {
397
-		err = configfs_create(dentry, mode, init_symlink);
398
-		if (err) {
399
-			struct configfs_dirent *sd = dentry->d_fsdata;
400
-			if (sd) {
401
-				spin_lock(&configfs_dirent_lock);
402
-				list_del_init(&sd->s_sibling);
403
-				spin_unlock(&configfs_dirent_lock);
404
-				configfs_put(sd);
405
-			}
406
-		}
407
-	}
408
-	return err;
370
+	err = configfs_make_dirent(p, dentry, target, mode, CONFIGFS_ITEM_LINK,
371
+			p->s_frag);
372
+	if (err)
373
+		return err;
374
+
375
+	inode = configfs_create(dentry, mode);
376
+	if (IS_ERR(inode))
377
+		goto out_remove;
378
+
379
+	inode->i_link = body;
380
+	inode->i_op = &configfs_symlink_inode_operations;
381
+	d_instantiate(dentry, inode);
382
+	dget(dentry);  /* pin link dentries in core */
383
+	return 0;
384
+
385
+out_remove:
386
+	configfs_remove_dirent(dentry);
387
+	return PTR_ERR(inode);
409388 }
410389 
411390 static void remove_dir(struct dentry * d)
412391 {
413392 	struct dentry * parent = dget(d->d_parent);
414
-	struct configfs_dirent * sd;
415393 
416
-	sd = d->d_fsdata;
417
-	spin_lock(&configfs_dirent_lock);
418
-	list_del_init(&sd->s_sibling);
419
-	spin_unlock(&configfs_dirent_lock);
420
-	configfs_put(sd);
394
+	configfs_remove_dirent(d);
395
+
421396 	if (d_really_is_positive(d))
422397 		simple_rmdir(d_inode(parent),d);
423398 
....@@ -458,20 +433,27 @@
458433 static int configfs_attach_attr(struct configfs_dirent * sd, struct dentry * dentry)
459434 {
460435 	struct configfs_attribute * attr = sd->s_element;
461
-	int error;
436
+	struct inode *inode;
462437 
463438 	spin_lock(&configfs_dirent_lock);
464439 	dentry->d_fsdata = configfs_get(sd);
465440 	sd->s_dentry = dentry;
466441 	spin_unlock(&configfs_dirent_lock);
467442 
468
-	error = configfs_create(dentry, (attr->ca_mode & S_IALLUGO) | S_IFREG,
469
-				(sd->s_type & CONFIGFS_ITEM_BIN_ATTR) ?
470
-					configfs_init_bin_file :
471
-					configfs_init_file);
472
-	if (error)
443
+	inode = configfs_create(dentry, (attr->ca_mode & S_IALLUGO) | S_IFREG);
444
+	if (IS_ERR(inode)) {
473445 		configfs_put(sd);
474
-	return error;
446
+		return PTR_ERR(inode);
447
+	}
448
+	if (sd->s_type & CONFIGFS_ITEM_BIN_ATTR) {
449
+		inode->i_size = 0;
450
+		inode->i_fop = &configfs_bin_file_operations;
451
+	} else {
452
+		inode->i_size = PAGE_SIZE;
453
+		inode->i_fop = &configfs_file_operations;
454
+	}
455
+	d_add(dentry, inode);
456
+	return 0;
475457 }
476458 
477459 static struct dentry * configfs_lookup(struct inode *dir,
....@@ -541,7 +523,7 @@
541523 	parent_sd->s_type |= CONFIGFS_USET_DROPPING;
542524 
543525 	ret = -EBUSY;
544
-	if (!list_empty(&parent_sd->s_links))
526
+	if (parent_sd->s_links)
545527 		goto out;
546528 
547529 	ret = 0;
....@@ -1194,7 +1176,7 @@
11941176 
11951177 /*
11961178  * Release the dependent linkage.  This is much simpler than
1197
- * configfs_depend_item() because we know that that the client driver is
1179
+ * configfs_depend_item() because we know that the client driver is
11981180  * pinned, thus the subsystem is pinned, and therefore configfs is pinned.
11991181  */
12001182 void configfs_undepend_item(struct config_item *target)
....@@ -1435,6 +1417,21 @@
14351417 	else
14361418 		ret = configfs_attach_item(parent_item, item, dentry, frag);
14371419 
1420
+	/* inherit uid/gid from process creating the directory */
1421
+	if (!uid_eq(current_fsuid(), GLOBAL_ROOT_UID) ||
1422
+	    !gid_eq(current_fsgid(), GLOBAL_ROOT_GID)) {
1423
+		struct iattr ia = {
1424
+			.ia_uid = current_fsuid(),
1425
+			.ia_gid = current_fsgid(),
1426
+			.ia_valid = ATTR_UID | ATTR_GID,
1427
+		};
1428
+		struct inode *inode = d_inode(dentry);
1429
+		inode->i_uid = ia.ia_uid;
1430
+		inode->i_gid = ia.ia_gid;
1431
+		/* the above manual assignments skip the permission checks */
1432
+		configfs_setattr(dentry, &ia);
1433
+	}
1434
+
14381435 	spin_lock(&configfs_dirent_lock);
14391436 	sd->s_type &= ~CONFIGFS_USET_IN_MKDIR;
14401437 	if (!ret)
....@@ -1600,44 +1597,6 @@
16001597 	.setattr	= configfs_setattr,
16011598 };
16021599 
1603
-#if 0
1604
-int configfs_rename_dir(struct config_item * item, const char *new_name)
1605
-{
1606
-	int error = 0;
1607
-	struct dentry * new_dentry, * parent;
1608
-
1609
-	if (!strcmp(config_item_name(item), new_name))
1610
-		return -EINVAL;
1611
-
1612
-	if (!item->parent)
1613
-		return -EINVAL;
1614
-
1615
-	down_write(&configfs_rename_sem);
1616
-	parent = item->parent->dentry;
1617
-
1618
-	inode_lock(d_inode(parent));
1619
-
1620
-	new_dentry = lookup_one_len(new_name, parent, strlen(new_name));
1621
-	if (!IS_ERR(new_dentry)) {
1622
-		if (d_really_is_negative(new_dentry)) {
1623
-			error = config_item_set_name(item, "%s", new_name);
1624
-			if (!error) {
1625
-				d_add(new_dentry, NULL);
1626
-				d_move(item->dentry, new_dentry);
1627
-			}
1628
-			else
1629
-				d_delete(new_dentry);
1630
-		} else
1631
-			error = -EEXIST;
1632
-		dput(new_dentry);
1633
-	}
1634
-	inode_unlock(d_inode(parent));
1635
-	up_write(&configfs_rename_sem);
1636
-
1637
-	return error;
1638
-}
1639
-#endif
1640
-
16411600 static int configfs_dir_open(struct inode *inode, struct file *file)
16421601 {
16431602 	struct dentry * dentry = file->f_path.dentry;
....@@ -1752,9 +1711,11 @@
17521711 	switch (whence) {
17531712 		case 1:
17541713 			offset += file->f_pos;
1714
+			fallthrough;
17551715 		case 0:
17561716 			if (offset >= 0)
17571717 				break;
1718
+			fallthrough;
17581719 		default:
17591720 			return -EINVAL;
17601721 	}
....@@ -1867,7 +1828,8 @@
18671828 	configfs_detach_group(&group->cg_item);
18681829 	d_inode(dentry)->i_flags |= S_DEAD;
18691830 	dont_mount(dentry);
1870
-	d_delete(dentry);
1831
+	d_drop(dentry);
1832
+	fsnotify_rmdir(d_inode(parent), dentry);
18711833 	inode_unlock(d_inode(parent));
18721834 
18731835 	dput(dentry);
....@@ -2014,7 +1976,8 @@
20141976 	dont_mount(dentry);
20151977 	inode_unlock(d_inode(dentry));
20161978 
2017
-	d_delete(dentry);
1979
+	d_drop(dentry);
1980
+	fsnotify_rmdir(d_inode(root), dentry);
20181981 
20191982 	inode_unlock(d_inode(root));
20201983