xref: /linux/fs/ntfs3/namei.c (revision 6f7e6393d1ce636bb7ec77a7fe7b77458fddf701) 
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  *
4  * Copyright (C) 2019-2021 Paragon Software GmbH, All rights reserved.
5  *
6  */
7 
8 #include <linux/fs.h>
9 #include <linux/nls.h>
10 #include <linux/ctype.h>
11 #include <linux/posix_acl.h>
12 
13 #include "debug.h"
14 #include "ntfs.h"
15 #include "ntfs_fs.h"
16 
17 /*
18  * fill_name_de - Format NTFS_DE in @buf.
19  */
20 int fill_name_de(struct ntfs_sb_info *sbi, void *buf, const struct qstr *name,
21 		 const struct cpu_str *uni)
22 {
23 	int err;
24 	struct NTFS_DE *e = buf;
25 	u16 data_size;
26 	struct ATTR_FILE_NAME *fname = (struct ATTR_FILE_NAME *)(e + 1);
27 
28 #ifndef CONFIG_NTFS3_64BIT_CLUSTER
29 	e->ref.high = fname->home.high = 0;
30 #endif
31 	if (uni) {
32 #ifdef __BIG_ENDIAN
33 		int ulen = uni->len;
34 		__le16 *uname = fname->name;
35 		const u16 *name_cpu = uni->name;
36 
37 		while (ulen--)
38 			*uname++ = cpu_to_le16(*name_cpu++);
39 #else
40 		memcpy(fname->name, uni->name, uni->len * sizeof(u16));
41 #endif
42 		fname->name_len = uni->len;
43 
44 	} else {
45 		/* Convert input string to unicode. */
46 		err = ntfs_nls_to_utf16(sbi, name->name, name->len,
47 					(struct cpu_str *)&fname->name_len,
48 					NTFS_NAME_LEN, UTF16_LITTLE_ENDIAN);
49 		if (err < 0)
50 			return err;
51 	}
52 
53 	fname->type = FILE_NAME_POSIX;
54 	data_size = fname_full_size(fname);
55 
56 	e->size = cpu_to_le16(ALIGN(data_size, 8) + sizeof(struct NTFS_DE));
57 	e->key_size = cpu_to_le16(data_size);
58 	e->flags = 0;
59 	e->res = 0;
60 
61 	return 0;
62 }
63 
64 /*
65  * ntfs_lookup - inode_operations::lookup
66  */
67 static struct dentry *ntfs_lookup(struct inode *dir, struct dentry *dentry,
68 				  u32 flags)
69 {
70 	struct ntfs_inode *ni = ntfs_i(dir);
71 	struct cpu_str *uni = kmalloc(PATH_MAX, GFP_KERNEL);
72 	struct inode *inode;
73 	int err;
74 
75 	if (!uni)
76 		inode = ERR_PTR(-ENOMEM);
77 	else {
78 		err = ntfs_nls_to_utf16(ni->mi.sbi, dentry->d_name.name,
79 					dentry->d_name.len, uni, NTFS_NAME_LEN,
80 					UTF16_HOST_ENDIAN);
81 		if (err < 0)
82 			inode = ERR_PTR(err);
83 		else {
84 			ni_lock_dir(ni);
85 			inode = dir_search_u(dir, uni, NULL);
86 			ni_unlock(ni);
87 		}
88 		kfree(uni);
89 	}
90 
91 	/*
92 	 * Check for a null pointer
93 	 * If the MFT record of ntfs inode is not a base record, inode->i_op can be NULL.
94 	 * This causes null pointer dereference in d_splice_alias().
95 	 */
96 	if (!IS_ERR_OR_NULL(inode) && !inode->i_op) {
97 		iput(inode);
98 		inode = ERR_PTR(-EINVAL);
99 	}
100 
101 	return d_splice_alias(inode, dentry);
102 }
103 
104 /*
105  * ntfs_create - inode_operations::create
106  */
107 static int ntfs_create(struct mnt_idmap *idmap, struct inode *dir,
108 		       struct dentry *dentry, umode_t mode, bool excl)
109 {
110 	return ntfs_create_inode(idmap, dir, dentry, NULL, S_IFREG | mode, 0,
111 				 NULL, 0, NULL);
112 }
113 
114 /*
115  * ntfs_mknod - inode_operations::mknod
116  */
117 static int ntfs_mknod(struct mnt_idmap *idmap, struct inode *dir,
118 		      struct dentry *dentry, umode_t mode, dev_t rdev)
119 {
120 	return ntfs_create_inode(idmap, dir, dentry, NULL, mode, rdev, NULL, 0,
121 				 NULL);
122 }
123 
124 /*
125  * ntfs_link - inode_operations::link
126  */
127 static int ntfs_link(struct dentry *ode, struct inode *dir, struct dentry *de)
128 {
129 	int err;
130 	struct inode *inode = d_inode(ode);
131 	struct ntfs_inode *ni = ntfs_i(inode);
132 
133 	if (S_ISDIR(inode->i_mode))
134 		return -EPERM;
135 
136 	if (inode->i_nlink >= NTFS_LINK_MAX)
137 		return -EMLINK;
138 
139 	ni_lock_dir(ntfs_i(dir));
140 	if (inode != dir)
141 		ni_lock(ni);
142 
143 	inc_nlink(inode);
144 	ihold(inode);
145 
146 	err = ntfs_link_inode(inode, de);
147 
148 	if (!err) {
149 		inode_set_ctime_current(inode);
150 		inode_set_mtime_to_ts(dir, inode_set_ctime_current(dir));
151 		mark_inode_dirty(inode);
152 		mark_inode_dirty(dir);
153 		d_instantiate(de, inode);
154 	} else {
155 		drop_nlink(inode);
156 		iput(inode);
157 	}
158 
159 	if (inode != dir)
160 		ni_unlock(ni);
161 	ni_unlock(ntfs_i(dir));
162 
163 	return err;
164 }
165 
166 /*
167  * ntfs_unlink - inode_operations::unlink
168  */
169 static int ntfs_unlink(struct inode *dir, struct dentry *dentry)
170 {
171 	struct ntfs_inode *ni = ntfs_i(dir);
172 	int err;
173 
174 	/* Avoid any operation if inode is bad. */
175 	if (unlikely(is_bad_ni(ni)))
176 		return -EINVAL;
177 
178 	if (unlikely(ntfs3_forced_shutdown(dir->i_sb)))
179 		return -EIO;
180 
181 	ni_lock_dir(ni);
182 
183 	err = ntfs_unlink_inode(dir, dentry);
184 
185 	ni_unlock(ni);
186 
187 	return err;
188 }
189 
190 /*
191  * ntfs_symlink - inode_operations::symlink
192  */
193 static int ntfs_symlink(struct mnt_idmap *idmap, struct inode *dir,
194 			struct dentry *dentry, const char *symname)
195 {
196 	u32 size = strlen(symname);
197 
198 	/* Avoid any operation if inode is bad. */
199 	if (unlikely(is_bad_ni(ntfs_i(dir))))
200 		return -EINVAL;
201 
202 	if (unlikely(ntfs3_forced_shutdown(dir->i_sb)))
203 		return -EIO;
204 
205 	return ntfs_create_inode(idmap, dir, dentry, NULL, S_IFLNK | 0777, 0,
206 				 symname, size, NULL);
207 }
208 
209 /*
210  * ntfs_mkdir - inode_operations::mkdir
211  */
212 static struct dentry *ntfs_mkdir(struct mnt_idmap *idmap, struct inode *dir,
213 				 struct dentry *dentry, umode_t mode)
214 {
215 	return ERR_PTR(ntfs_create_inode(idmap, dir, dentry, NULL,
216 					 S_IFDIR | mode, 0, NULL, 0, NULL));
217 }
218 
219 /*
220  * ntfs_rmdir - inode_operations::rmdir
221  */
222 static int ntfs_rmdir(struct inode *dir, struct dentry *dentry)
223 {
224 	struct ntfs_inode *ni = ntfs_i(dir);
225 	int err;
226 
227 	/* Avoid any operation if inode is bad. */
228 	if (unlikely(is_bad_ni(ni)))
229 		return -EINVAL;
230 
231 	if (unlikely(ntfs3_forced_shutdown(dir->i_sb)))
232 		return -EIO;
233 
234 	ni_lock_dir(ni);
235 
236 	err = ntfs_unlink_inode(dir, dentry);
237 
238 	ni_unlock(ni);
239 
240 	return err;
241 }
242 
243 /*
244  * ntfs_rename - inode_operations::rename
245  */
246 static int ntfs_rename(struct mnt_idmap *idmap, struct inode *dir,
247 		       struct dentry *dentry, struct inode *new_dir,
248 		       struct dentry *new_dentry, u32 flags)
249 {
250 	int err;
251 	struct super_block *sb = dir->i_sb;
252 	struct ntfs_sb_info *sbi = sb->s_fs_info;
253 	struct ntfs_inode *dir_ni = ntfs_i(dir);
254 	struct ntfs_inode *new_dir_ni = ntfs_i(new_dir);
255 	struct inode *inode = d_inode(dentry);
256 	struct ntfs_inode *ni = ntfs_i(inode);
257 	struct inode *new_inode = d_inode(new_dentry);
258 	struct NTFS_DE *de, *new_de;
259 	bool is_same;
260 	/*
261 	 * de		- memory of PATH_MAX bytes:
262 	 * [0-1024)	- original name (dentry->d_name)
263 	 * [1024-2048)	- paired to original name, usually DOS variant of dentry->d_name
264 	 * [2048-3072)	- new name (new_dentry->d_name)
265 	 */
266 	static_assert(SIZEOF_ATTRIBUTE_FILENAME_MAX + SIZEOF_RESIDENT < 1024);
267 	static_assert(SIZEOF_ATTRIBUTE_FILENAME_MAX + sizeof(struct NTFS_DE) <
268 		      1024);
269 	static_assert(PATH_MAX >= 4 * 1024);
270 
271 	/* Avoid any operation if inode is bad. */
272 	if (unlikely(is_bad_ni(ni)))
273 		return -EINVAL;
274 
275 	if (unlikely(ntfs3_forced_shutdown(sb)))
276 		return -EIO;
277 
278 	if (flags & ~RENAME_NOREPLACE)
279 		return -EINVAL;
280 
281 	is_same = dentry->d_name.len == new_dentry->d_name.len &&
282 		  !memcmp(dentry->d_name.name, new_dentry->d_name.name,
283 			  dentry->d_name.len);
284 
285 	if (is_same && dir == new_dir) {
286 		/* Nothing to do. */
287 		return 0;
288 	}
289 
290 	if (ntfs_is_meta_file(sbi, inode->i_ino)) {
291 		/* Should we print an error? */
292 		return -EINVAL;
293 	}
294 
295 	if (new_inode) {
296 		/* Target name exists. Unlink it. */
297 		dget(new_dentry);
298 		ni_lock_dir(new_dir_ni);
299 		err = ntfs_unlink_inode(new_dir, new_dentry);
300 		ni_unlock(new_dir_ni);
301 		dput(new_dentry);
302 		if (err)
303 			return err;
304 	}
305 
306 	de = kmalloc(PATH_MAX, GFP_KERNEL);
307 	if (!de)
308 		return -ENOMEM;
309 
310 	/* Translate dentry->d_name into unicode form. */
311 	err = fill_name_de(sbi, de, &dentry->d_name, NULL);
312 	if (err < 0)
313 		goto out;
314 
315 	if (is_same) {
316 		/* Reuse 'de'. */
317 		new_de = de;
318 	} else {
319 		/* Translate new_dentry->d_name into unicode form. */
320 		new_de = Add2Ptr(de, 2048);
321 		err = fill_name_de(sbi, new_de, &new_dentry->d_name, NULL);
322 		if (err < 0)
323 			goto out;
324 	}
325 
326 	ni_lock_dir(dir_ni);
327 	ni_lock(ni);
328 	if (dir_ni != new_dir_ni)
329 		ni_lock_dir2(new_dir_ni);
330 
331 	err = ni_rename(dir_ni, new_dir_ni, ni, de, new_de);
332 	if (!err) {
333 		simple_rename_timestamp(dir, dentry, new_dir, new_dentry);
334 		mark_inode_dirty(inode);
335 		mark_inode_dirty(dir);
336 		if (dir != new_dir)
337 			mark_inode_dirty(new_dir);
338 
339 		if (IS_DIRSYNC(dir))
340 			ntfs_sync_inode(dir);
341 
342 		if (IS_DIRSYNC(new_dir))
343 			ntfs_sync_inode(inode);
344 	}
345 
346 	if (dir_ni != new_dir_ni)
347 		ni_unlock(new_dir_ni);
348 	ni_unlock(ni);
349 	ni_unlock(dir_ni);
350 out:
351 	kfree(de);
352 	return err;
353 }
354 
355 struct dentry *ntfs3_get_parent(struct dentry *child)
356 {
357 	struct inode *inode = d_inode(child);
358 	struct ntfs_inode *ni = ntfs_i(inode);
359 
360 	struct ATTR_LIST_ENTRY *le = NULL;
361 	struct ATTRIB *attr = NULL;
362 	struct ATTR_FILE_NAME *fname;
363 
364 	while ((attr = ni_find_attr(ni, attr, &le, ATTR_NAME, NULL, 0, NULL,
365 				    NULL))) {
366 		fname = resident_data_ex(attr, SIZEOF_ATTRIBUTE_FILENAME);
367 		if (!fname)
368 			continue;
369 
370 		return d_obtain_alias(
371 			ntfs_iget5(inode->i_sb, &fname->home, NULL));
372 	}
373 
374 	return ERR_PTR(-ENOENT);
375 }
376 
377 /*
378  * dentry_operations::d_hash
379  */
380 static int ntfs_d_hash(const struct dentry *dentry, struct qstr *name)
381 {
382 	struct ntfs_sb_info *sbi;
383 	const char *n = name->name;
384 	unsigned int len = name->len;
385 	unsigned long hash;
386 	struct cpu_str *uni;
387 	unsigned int c;
388 	int err;
389 
390 	/* First try fast implementation. */
391 	hash = init_name_hash(dentry);
392 
393 	for (;;) {
394 		if (!len--) {
395 			name->hash = end_name_hash(hash);
396 			return 0;
397 		}
398 
399 		c = *n++;
400 		if (c >= 0x80)
401 			break;
402 
403 		hash = partial_name_hash(toupper(c), hash);
404 	}
405 
406 	/*
407 	 * Try slow way with current upcase table
408 	 */
409 	uni = kmalloc(PATH_MAX, GFP_NOWAIT);
410 	if (!uni)
411 		return -ENOMEM;
412 
413 	sbi = dentry->d_sb->s_fs_info;
414 
415 	err = ntfs_nls_to_utf16(sbi, name->name, name->len, uni, NTFS_NAME_LEN,
416 				UTF16_HOST_ENDIAN);
417 	if (err < 0)
418 		goto out;
419 
420 	if (!err) {
421 		err = -EINVAL;
422 		goto out;
423 	}
424 
425 	hash = ntfs_names_hash(uni->name, uni->len, sbi->upcase,
426 			       init_name_hash(dentry));
427 	name->hash = end_name_hash(hash);
428 	err = 0;
429 
430 out:
431 	kfree(uni);
432 	return err;
433 }
434 
435 /*
436  * dentry_operations::d_compare
437  */
438 static int ntfs_d_compare(const struct dentry *dentry, unsigned int len1,
439 			  const char *str, const struct qstr *name)
440 {
441 	struct ntfs_sb_info *sbi;
442 	int ret;
443 	const char *n1 = str;
444 	const char *n2 = name->name;
445 	unsigned int len2 = name->len;
446 	unsigned int lm = min(len1, len2);
447 	unsigned char c1, c2;
448 	struct cpu_str *uni1;
449 	struct le_str *uni2;
450 
451 	/* First try fast implementation. */
452 	for (;;) {
453 		if (!lm--)
454 			return len1 != len2;
455 
456 		if ((c1 = *n1++) == (c2 = *n2++))
457 			continue;
458 
459 		if (c1 >= 0x80 || c2 >= 0x80)
460 			break;
461 
462 		if (toupper(c1) != toupper(c2))
463 			return 1;
464 	}
465 
466 	/*
467 	 * Try slow way with current upcase table
468 	 */
469 	sbi = dentry->d_sb->s_fs_info;
470 	uni1 = kmalloc(PATH_MAX, GFP_NOWAIT);
471 	if (!uni1)
472 		return -ENOMEM;
473 
474 	ret = ntfs_nls_to_utf16(sbi, str, len1, uni1, NTFS_NAME_LEN,
475 				UTF16_HOST_ENDIAN);
476 	if (ret < 0)
477 		goto out;
478 
479 	if (!ret) {
480 		ret = -EINVAL;
481 		goto out;
482 	}
483 
484 	uni2 = Add2Ptr(uni1, 2048);
485 
486 	ret = ntfs_nls_to_utf16(sbi, name->name, name->len,
487 				(struct cpu_str *)uni2, NTFS_NAME_LEN,
488 				UTF16_LITTLE_ENDIAN);
489 	if (ret < 0)
490 		goto out;
491 
492 	if (!ret) {
493 		ret = -EINVAL;
494 		goto out;
495 	}
496 
497 	ret = !ntfs_cmp_names_cpu(uni1, uni2, sbi->upcase, false) ? 0 : 1;
498 
499 out:
500 	kfree(uni1);
501 	return ret;
502 }
503 
504 // clang-format off
505 const struct inode_operations ntfs_dir_inode_operations = {
506 	.lookup		= ntfs_lookup,
507 	.create		= ntfs_create,
508 	.link		= ntfs_link,
509 	.unlink		= ntfs_unlink,
510 	.symlink	= ntfs_symlink,
511 	.mkdir		= ntfs_mkdir,
512 	.rmdir		= ntfs_rmdir,
513 	.mknod		= ntfs_mknod,
514 	.rename		= ntfs_rename,
515 	.get_acl	= ntfs_get_acl,
516 	.set_acl	= ntfs_set_acl,
517 	.setattr	= ntfs_setattr,
518 	.getattr	= ntfs_getattr,
519 	.listxattr	= ntfs_listxattr,
520 	.fiemap		= ntfs_fiemap,
521 };
522 
523 const struct inode_operations ntfs_special_inode_operations = {
524 	.setattr	= ntfs_setattr,
525 	.getattr	= ntfs_getattr,
526 	.listxattr	= ntfs_listxattr,
527 	.get_acl	= ntfs_get_acl,
528 	.set_acl	= ntfs_set_acl,
529 };
530 
531 const struct dentry_operations ntfs_dentry_ops = {
532 	.d_hash		= ntfs_d_hash,
533 	.d_compare	= ntfs_d_compare,
534 };
535 
536 // clang-format on
537