namei.c

  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 */
 20int 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 */
 67static 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 */
107static 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 */
117static 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 */
127static 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 */
169static 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 */
193static 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 */
212static 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 */
222static 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 */
246static 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);
350out:
351	kfree(de);
352	return err;
353}
354
355struct 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 */
380static 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
430out:
431	kfree(uni);
432	return err;
433}
434
435/*
436 * dentry_operations::d_compare
437 */
438static 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
499out:
500	kfree(uni1);
501	return ret;
502}
503
504// clang-format off
505const 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
523const 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
531const struct dentry_operations ntfs_dentry_ops = {
532	.d_hash		= ntfs_d_hash,
533	.d_compare	= ntfs_d_compare,
534};
535
536// clang-format on