xref: /linux/fs/ntfs3/namei.c (revision 43b46e6bc69c2aa4331cfd7fa4e2943a894339e5)
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 
11 #include "debug.h"
12 #include "ntfs.h"
13 #include "ntfs_fs.h"
14 
15 /*
16  * fill_name_de - Format NTFS_DE in @buf.
17  */
18 int fill_name_de(struct ntfs_sb_info *sbi, void *buf, const struct qstr *name,
19 		 const struct cpu_str *uni)
20 {
21 	int err;
22 	struct NTFS_DE *e = buf;
23 	u16 data_size;
24 	struct ATTR_FILE_NAME *fname = (struct ATTR_FILE_NAME *)(e + 1);
25 
26 #ifndef CONFIG_NTFS3_64BIT_CLUSTER
27 	e->ref.high = fname->home.high = 0;
28 #endif
29 	if (uni) {
30 #ifdef __BIG_ENDIAN
31 		int ulen = uni->len;
32 		__le16 *uname = fname->name;
33 		const u16 *name_cpu = uni->name;
34 
35 		while (ulen--)
36 			*uname++ = cpu_to_le16(*name_cpu++);
37 #else
38 		memcpy(fname->name, uni->name, uni->len * sizeof(u16));
39 #endif
40 		fname->name_len = uni->len;
41 
42 	} else {
43 		/* Convert input string to unicode. */
44 		err = ntfs_nls_to_utf16(sbi, name->name, name->len,
45 					(struct cpu_str *)&fname->name_len,
46 					NTFS_NAME_LEN, UTF16_LITTLE_ENDIAN);
47 		if (err < 0)
48 			return err;
49 	}
50 
51 	fname->type = FILE_NAME_POSIX;
52 	data_size = fname_full_size(fname);
53 
54 	e->size = cpu_to_le16(ALIGN(data_size, 8) + sizeof(struct NTFS_DE));
55 	e->key_size = cpu_to_le16(data_size);
56 	e->flags = 0;
57 	e->res = 0;
58 
59 	return 0;
60 }
61 
62 /*
63  * ntfs_lookup - inode_operations::lookup
64  */
65 static struct dentry *ntfs_lookup(struct inode *dir, struct dentry *dentry,
66 				  u32 flags)
67 {
68 	struct ntfs_inode *ni = ntfs_i(dir);
69 	struct cpu_str *uni = __getname();
70 	struct inode *inode;
71 	int err;
72 
73 	if (!uni)
74 		inode = ERR_PTR(-ENOMEM);
75 	else {
76 		err = ntfs_nls_to_utf16(ni->mi.sbi, dentry->d_name.name,
77 					dentry->d_name.len, uni, NTFS_NAME_LEN,
78 					UTF16_HOST_ENDIAN);
79 		if (err < 0)
80 			inode = ERR_PTR(err);
81 		else {
82 			ni_lock(ni);
83 			inode = dir_search_u(dir, uni, NULL);
84 			ni_unlock(ni);
85 		}
86 		__putname(uni);
87 	}
88 
89 	return d_splice_alias(inode, dentry);
90 }
91 
92 /*
93  * ntfs_create - inode_operations::create
94  */
95 static int ntfs_create(struct user_namespace *mnt_userns, struct inode *dir,
96 		       struct dentry *dentry, umode_t mode, bool excl)
97 {
98 	struct inode *inode;
99 
100 	inode = ntfs_create_inode(mnt_userns, dir, dentry, NULL, S_IFREG | mode,
101 				  0, NULL, 0, NULL);
102 
103 	return IS_ERR(inode) ? PTR_ERR(inode) : 0;
104 }
105 
106 /*
107  * ntfs_mknod
108  *
109  * inode_operations::mknod
110  */
111 static int ntfs_mknod(struct user_namespace *mnt_userns, struct inode *dir,
112 		      struct dentry *dentry, umode_t mode, dev_t rdev)
113 {
114 	struct inode *inode;
115 
116 	inode = ntfs_create_inode(mnt_userns, dir, dentry, NULL, mode, rdev,
117 				  NULL, 0, NULL);
118 
119 	return IS_ERR(inode) ? PTR_ERR(inode) : 0;
120 }
121 
122 /*
123  * ntfs_link - inode_operations::link
124  */
125 static int ntfs_link(struct dentry *ode, struct inode *dir, struct dentry *de)
126 {
127 	int err;
128 	struct inode *inode = d_inode(ode);
129 	struct ntfs_inode *ni = ntfs_i(inode);
130 
131 	if (S_ISDIR(inode->i_mode))
132 		return -EPERM;
133 
134 	if (inode->i_nlink >= NTFS_LINK_MAX)
135 		return -EMLINK;
136 
137 	ni_lock_dir(ntfs_i(dir));
138 	if (inode != dir)
139 		ni_lock(ni);
140 
141 	inc_nlink(inode);
142 	ihold(inode);
143 
144 	err = ntfs_link_inode(inode, de);
145 
146 	if (!err) {
147 		dir->i_ctime = dir->i_mtime = inode->i_ctime =
148 			current_time(dir);
149 		mark_inode_dirty(inode);
150 		mark_inode_dirty(dir);
151 		d_instantiate(de, inode);
152 	} else {
153 		drop_nlink(inode);
154 		iput(inode);
155 	}
156 
157 	if (inode != dir)
158 		ni_unlock(ni);
159 	ni_unlock(ntfs_i(dir));
160 
161 	return err;
162 }
163 
164 /*
165  * ntfs_unlink - inode_operations::unlink
166  */
167 static int ntfs_unlink(struct inode *dir, struct dentry *dentry)
168 {
169 	struct ntfs_inode *ni = ntfs_i(dir);
170 	int err;
171 
172 	ni_lock_dir(ni);
173 
174 	err = ntfs_unlink_inode(dir, dentry);
175 
176 	ni_unlock(ni);
177 
178 	return err;
179 }
180 
181 /*
182  * ntfs_symlink - inode_operations::symlink
183  */
184 static int ntfs_symlink(struct user_namespace *mnt_userns, struct inode *dir,
185 			struct dentry *dentry, const char *symname)
186 {
187 	u32 size = strlen(symname);
188 	struct inode *inode;
189 
190 	inode = ntfs_create_inode(mnt_userns, dir, dentry, NULL, S_IFLNK | 0777,
191 				  0, symname, size, NULL);
192 
193 	return IS_ERR(inode) ? PTR_ERR(inode) : 0;
194 }
195 
196 /*
197  * ntfs_mkdir- inode_operations::mkdir
198  */
199 static int ntfs_mkdir(struct user_namespace *mnt_userns, struct inode *dir,
200 		      struct dentry *dentry, umode_t mode)
201 {
202 	struct inode *inode;
203 
204 	inode = ntfs_create_inode(mnt_userns, dir, dentry, NULL, S_IFDIR | mode,
205 				  0, NULL, 0, NULL);
206 
207 	return IS_ERR(inode) ? PTR_ERR(inode) : 0;
208 }
209 
210 /*
211  * ntfs_rmdir - inode_operations::rmdir
212  */
213 static int ntfs_rmdir(struct inode *dir, struct dentry *dentry)
214 {
215 	struct ntfs_inode *ni = ntfs_i(dir);
216 	int err;
217 
218 	ni_lock_dir(ni);
219 
220 	err = ntfs_unlink_inode(dir, dentry);
221 
222 	ni_unlock(ni);
223 
224 	return err;
225 }
226 
227 /*
228  * ntfs_rename - inode_operations::rename
229  */
230 static int ntfs_rename(struct user_namespace *mnt_userns, struct inode *dir,
231 		       struct dentry *dentry, struct inode *new_dir,
232 		       struct dentry *new_dentry, u32 flags)
233 {
234 	int err;
235 	struct super_block *sb = dir->i_sb;
236 	struct ntfs_sb_info *sbi = sb->s_fs_info;
237 	struct ntfs_inode *dir_ni = ntfs_i(dir);
238 	struct ntfs_inode *new_dir_ni = ntfs_i(new_dir);
239 	struct inode *inode = d_inode(dentry);
240 	struct ntfs_inode *ni = ntfs_i(inode);
241 	struct inode *new_inode = d_inode(new_dentry);
242 	struct NTFS_DE *de, *new_de;
243 	bool is_same, is_bad;
244 	/*
245 	 * de		- memory of PATH_MAX bytes:
246 	 * [0-1024)	- original name (dentry->d_name)
247 	 * [1024-2048)	- paired to original name, usually DOS variant of dentry->d_name
248 	 * [2048-3072)	- new name (new_dentry->d_name)
249 	 */
250 	static_assert(SIZEOF_ATTRIBUTE_FILENAME_MAX + SIZEOF_RESIDENT < 1024);
251 	static_assert(SIZEOF_ATTRIBUTE_FILENAME_MAX + sizeof(struct NTFS_DE) <
252 		      1024);
253 	static_assert(PATH_MAX >= 4 * 1024);
254 
255 	if (flags & ~RENAME_NOREPLACE)
256 		return -EINVAL;
257 
258 	is_same = dentry->d_name.len == new_dentry->d_name.len &&
259 		  !memcmp(dentry->d_name.name, new_dentry->d_name.name,
260 			  dentry->d_name.len);
261 
262 	if (is_same && dir == new_dir) {
263 		/* Nothing to do. */
264 		return 0;
265 	}
266 
267 	if (ntfs_is_meta_file(sbi, inode->i_ino)) {
268 		/* Should we print an error? */
269 		return -EINVAL;
270 	}
271 
272 	if (new_inode) {
273 		/* Target name exists. Unlink it. */
274 		dget(new_dentry);
275 		ni_lock_dir(new_dir_ni);
276 		err = ntfs_unlink_inode(new_dir, new_dentry);
277 		ni_unlock(new_dir_ni);
278 		dput(new_dentry);
279 		if (err)
280 			return err;
281 	}
282 
283 	/* Allocate PATH_MAX bytes. */
284 	de = __getname();
285 	if (!de)
286 		return -ENOMEM;
287 
288 	/* Translate dentry->d_name into unicode form. */
289 	err = fill_name_de(sbi, de, &dentry->d_name, NULL);
290 	if (err < 0)
291 		goto out;
292 
293 	if (is_same) {
294 		/* Reuse 'de'. */
295 		new_de = de;
296 	} else {
297 		/* Translate new_dentry->d_name into unicode form. */
298 		new_de = Add2Ptr(de, 2048);
299 		err = fill_name_de(sbi, new_de, &new_dentry->d_name, NULL);
300 		if (err < 0)
301 			goto out;
302 	}
303 
304 	ni_lock_dir(dir_ni);
305 	ni_lock(ni);
306 
307 	is_bad = false;
308 	err = ni_rename(dir_ni, new_dir_ni, ni, de, new_de, &is_bad);
309 	if (is_bad) {
310 		/* Restore after failed rename failed too. */
311 		_ntfs_bad_inode(inode);
312 	} else if (!err) {
313 		inode->i_ctime = dir->i_ctime = dir->i_mtime =
314 			current_time(dir);
315 		mark_inode_dirty(inode);
316 		mark_inode_dirty(dir);
317 		if (dir != new_dir) {
318 			new_dir->i_mtime = new_dir->i_ctime = dir->i_ctime;
319 			mark_inode_dirty(new_dir);
320 		}
321 
322 		if (IS_DIRSYNC(dir))
323 			ntfs_sync_inode(dir);
324 
325 		if (IS_DIRSYNC(new_dir))
326 			ntfs_sync_inode(inode);
327 	}
328 
329 	ni_unlock(ni);
330 	ni_unlock(dir_ni);
331 out:
332 	__putname(de);
333 	return err;
334 }
335 
336 struct dentry *ntfs3_get_parent(struct dentry *child)
337 {
338 	struct inode *inode = d_inode(child);
339 	struct ntfs_inode *ni = ntfs_i(inode);
340 
341 	struct ATTR_LIST_ENTRY *le = NULL;
342 	struct ATTRIB *attr = NULL;
343 	struct ATTR_FILE_NAME *fname;
344 
345 	while ((attr = ni_find_attr(ni, attr, &le, ATTR_NAME, NULL, 0, NULL,
346 				    NULL))) {
347 		fname = resident_data_ex(attr, SIZEOF_ATTRIBUTE_FILENAME);
348 		if (!fname)
349 			continue;
350 
351 		return d_obtain_alias(
352 			ntfs_iget5(inode->i_sb, &fname->home, NULL));
353 	}
354 
355 	return ERR_PTR(-ENOENT);
356 }
357 
358 // clang-format off
359 const struct inode_operations ntfs_dir_inode_operations = {
360 	.lookup		= ntfs_lookup,
361 	.create		= ntfs_create,
362 	.link		= ntfs_link,
363 	.unlink		= ntfs_unlink,
364 	.symlink	= ntfs_symlink,
365 	.mkdir		= ntfs_mkdir,
366 	.rmdir		= ntfs_rmdir,
367 	.mknod		= ntfs_mknod,
368 	.rename		= ntfs_rename,
369 	.permission	= ntfs_permission,
370 	.get_acl	= ntfs_get_acl,
371 	.set_acl	= ntfs_set_acl,
372 	.setattr	= ntfs3_setattr,
373 	.getattr	= ntfs_getattr,
374 	.listxattr	= ntfs_listxattr,
375 	.fiemap		= ntfs_fiemap,
376 };
377 
378 const struct inode_operations ntfs_special_inode_operations = {
379 	.setattr	= ntfs3_setattr,
380 	.getattr	= ntfs_getattr,
381 	.listxattr	= ntfs_listxattr,
382 	.get_acl	= ntfs_get_acl,
383 	.set_acl	= ntfs_set_acl,
384 };
385 // clang-format on
386