xref: /linux/fs/f2fs/acl.c (revision 55f1b540d893da740a81200450014c45a8103f54) 
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * fs/f2fs/acl.c
4  *
5  * Copyright (c) 2012 Samsung Electronics Co., Ltd.
6  *             http://www.samsung.com/
7  *
8  * Portions of this code from linux/fs/ext2/acl.c
9  *
10  * Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de>
11  */
12 #include <linux/f2fs_fs.h>
13 #include "f2fs.h"
14 #include "xattr.h"
15 #include "acl.h"
16 
17 static inline size_t f2fs_acl_size(int count)
18 {
19 	if (count <= 4) {
20 		return sizeof(struct f2fs_acl_header) +
21 			count * sizeof(struct f2fs_acl_entry_short);
22 	} else {
23 		return sizeof(struct f2fs_acl_header) +
24 			4 * sizeof(struct f2fs_acl_entry_short) +
25 			(count - 4) * sizeof(struct f2fs_acl_entry);
26 	}
27 }
28 
29 static inline int f2fs_acl_count(size_t size)
30 {
31 	ssize_t s;
32 
33 	size -= sizeof(struct f2fs_acl_header);
34 	s = size - 4 * sizeof(struct f2fs_acl_entry_short);
35 	if (s < 0) {
36 		if (size % sizeof(struct f2fs_acl_entry_short))
37 			return -1;
38 		return size / sizeof(struct f2fs_acl_entry_short);
39 	} else {
40 		if (s % sizeof(struct f2fs_acl_entry))
41 			return -1;
42 		return s / sizeof(struct f2fs_acl_entry) + 4;
43 	}
44 }
45 
46 static struct posix_acl *f2fs_acl_from_disk(const char *value, size_t size)
47 {
48 	int i, count;
49 	struct posix_acl *acl;
50 	struct f2fs_acl_header *hdr = (struct f2fs_acl_header *)value;
51 	struct f2fs_acl_entry *entry = (struct f2fs_acl_entry *)(hdr + 1);
52 	const char *end = value + size;
53 
54 	if (size < sizeof(struct f2fs_acl_header))
55 		return ERR_PTR(-EINVAL);
56 
57 	if (hdr->a_version != cpu_to_le32(F2FS_ACL_VERSION))
58 		return ERR_PTR(-EINVAL);
59 
60 	count = f2fs_acl_count(size);
61 	if (count < 0)
62 		return ERR_PTR(-EINVAL);
63 	if (count == 0)
64 		return NULL;
65 
66 	acl = posix_acl_alloc(count, GFP_NOFS);
67 	if (!acl)
68 		return ERR_PTR(-ENOMEM);
69 
70 	for (i = 0; i < count; i++) {
71 
72 		if ((char *)entry > end)
73 			goto fail;
74 
75 		acl->a_entries[i].e_tag  = le16_to_cpu(entry->e_tag);
76 		acl->a_entries[i].e_perm = le16_to_cpu(entry->e_perm);
77 
78 		switch (acl->a_entries[i].e_tag) {
79 		case ACL_USER_OBJ:
80 		case ACL_GROUP_OBJ:
81 		case ACL_MASK:
82 		case ACL_OTHER:
83 			entry = (struct f2fs_acl_entry *)((char *)entry +
84 					sizeof(struct f2fs_acl_entry_short));
85 			break;
86 
87 		case ACL_USER:
88 			acl->a_entries[i].e_uid =
89 				make_kuid(&init_user_ns,
90 						le32_to_cpu(entry->e_id));
91 			entry = (struct f2fs_acl_entry *)((char *)entry +
92 					sizeof(struct f2fs_acl_entry));
93 			break;
94 		case ACL_GROUP:
95 			acl->a_entries[i].e_gid =
96 				make_kgid(&init_user_ns,
97 						le32_to_cpu(entry->e_id));
98 			entry = (struct f2fs_acl_entry *)((char *)entry +
99 					sizeof(struct f2fs_acl_entry));
100 			break;
101 		default:
102 			goto fail;
103 		}
104 	}
105 	if ((char *)entry != end)
106 		goto fail;
107 	return acl;
108 fail:
109 	posix_acl_release(acl);
110 	return ERR_PTR(-EINVAL);
111 }
112 
113 static void *f2fs_acl_to_disk(struct f2fs_sb_info *sbi,
114 				const struct posix_acl *acl, size_t *size)
115 {
116 	struct f2fs_acl_header *f2fs_acl;
117 	struct f2fs_acl_entry *entry;
118 	int i;
119 
120 	f2fs_acl = f2fs_kmalloc(sbi, sizeof(struct f2fs_acl_header) +
121 			acl->a_count * sizeof(struct f2fs_acl_entry),
122 			GFP_NOFS);
123 	if (!f2fs_acl)
124 		return ERR_PTR(-ENOMEM);
125 
126 	f2fs_acl->a_version = cpu_to_le32(F2FS_ACL_VERSION);
127 	entry = (struct f2fs_acl_entry *)(f2fs_acl + 1);
128 
129 	for (i = 0; i < acl->a_count; i++) {
130 
131 		entry->e_tag  = cpu_to_le16(acl->a_entries[i].e_tag);
132 		entry->e_perm = cpu_to_le16(acl->a_entries[i].e_perm);
133 
134 		switch (acl->a_entries[i].e_tag) {
135 		case ACL_USER:
136 			entry->e_id = cpu_to_le32(
137 					from_kuid(&init_user_ns,
138 						acl->a_entries[i].e_uid));
139 			entry = (struct f2fs_acl_entry *)((char *)entry +
140 					sizeof(struct f2fs_acl_entry));
141 			break;
142 		case ACL_GROUP:
143 			entry->e_id = cpu_to_le32(
144 					from_kgid(&init_user_ns,
145 						acl->a_entries[i].e_gid));
146 			entry = (struct f2fs_acl_entry *)((char *)entry +
147 					sizeof(struct f2fs_acl_entry));
148 			break;
149 		case ACL_USER_OBJ:
150 		case ACL_GROUP_OBJ:
151 		case ACL_MASK:
152 		case ACL_OTHER:
153 			entry = (struct f2fs_acl_entry *)((char *)entry +
154 					sizeof(struct f2fs_acl_entry_short));
155 			break;
156 		default:
157 			goto fail;
158 		}
159 	}
160 	*size = f2fs_acl_size(acl->a_count);
161 	return (void *)f2fs_acl;
162 
163 fail:
164 	kfree(f2fs_acl);
165 	return ERR_PTR(-EINVAL);
166 }
167 
168 static struct posix_acl *__f2fs_get_acl(struct inode *inode, int type,
169 						struct page *dpage)
170 {
171 	int name_index = F2FS_XATTR_INDEX_POSIX_ACL_DEFAULT;
172 	void *value = NULL;
173 	struct posix_acl *acl;
174 	int retval;
175 
176 	if (type == ACL_TYPE_ACCESS)
177 		name_index = F2FS_XATTR_INDEX_POSIX_ACL_ACCESS;
178 
179 	retval = f2fs_getxattr(inode, name_index, "", NULL, 0, dpage);
180 	if (retval > 0) {
181 		value = f2fs_kmalloc(F2FS_I_SB(inode), retval, GFP_F2FS_ZERO);
182 		if (!value)
183 			return ERR_PTR(-ENOMEM);
184 		retval = f2fs_getxattr(inode, name_index, "", value,
185 							retval, dpage);
186 	}
187 
188 	if (retval > 0)
189 		acl = f2fs_acl_from_disk(value, retval);
190 	else if (retval == -ENODATA)
191 		acl = NULL;
192 	else
193 		acl = ERR_PTR(retval);
194 	kfree(value);
195 
196 	return acl;
197 }
198 
199 struct posix_acl *f2fs_get_acl(struct inode *inode, int type, bool rcu)
200 {
201 	if (rcu)
202 		return ERR_PTR(-ECHILD);
203 
204 	return __f2fs_get_acl(inode, type, NULL);
205 }
206 
207 static int f2fs_acl_update_mode(struct mnt_idmap *idmap,
208 				struct inode *inode, umode_t *mode_p,
209 				struct posix_acl **acl)
210 {
211 	umode_t mode = inode->i_mode;
212 	int error;
213 
214 	if (is_inode_flag_set(inode, FI_ACL_MODE))
215 		mode = F2FS_I(inode)->i_acl_mode;
216 
217 	error = posix_acl_equiv_mode(*acl, &mode);
218 	if (error < 0)
219 		return error;
220 	if (error == 0)
221 		*acl = NULL;
222 	if (!in_group_or_capable(idmap, inode, i_gid_into_vfsgid(idmap, inode)))
223 		mode &= ~S_ISGID;
224 	*mode_p = mode;
225 	return 0;
226 }
227 
228 static int __f2fs_set_acl(struct mnt_idmap *idmap,
229 			struct inode *inode, int type,
230 			struct posix_acl *acl, struct page *ipage)
231 {
232 	int name_index;
233 	void *value = NULL;
234 	size_t size = 0;
235 	int error;
236 	umode_t mode = inode->i_mode;
237 
238 	switch (type) {
239 	case ACL_TYPE_ACCESS:
240 		name_index = F2FS_XATTR_INDEX_POSIX_ACL_ACCESS;
241 		if (acl && !ipage) {
242 			error = f2fs_acl_update_mode(idmap, inode,
243 								&mode, &acl);
244 			if (error)
245 				return error;
246 			set_acl_inode(inode, mode);
247 		}
248 		break;
249 
250 	case ACL_TYPE_DEFAULT:
251 		name_index = F2FS_XATTR_INDEX_POSIX_ACL_DEFAULT;
252 		if (!S_ISDIR(inode->i_mode))
253 			return acl ? -EACCES : 0;
254 		break;
255 
256 	default:
257 		return -EINVAL;
258 	}
259 
260 	if (acl) {
261 		value = f2fs_acl_to_disk(F2FS_I_SB(inode), acl, &size);
262 		if (IS_ERR(value)) {
263 			clear_inode_flag(inode, FI_ACL_MODE);
264 			return PTR_ERR(value);
265 		}
266 	}
267 
268 	error = f2fs_setxattr(inode, name_index, "", value, size, ipage, 0);
269 
270 	kfree(value);
271 	if (!error)
272 		set_cached_acl(inode, type, acl);
273 
274 	clear_inode_flag(inode, FI_ACL_MODE);
275 	return error;
276 }
277 
278 int f2fs_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
279 		 struct posix_acl *acl, int type)
280 {
281 	struct inode *inode = d_inode(dentry);
282 
283 	if (unlikely(f2fs_cp_error(F2FS_I_SB(inode))))
284 		return -EIO;
285 
286 	return __f2fs_set_acl(idmap, inode, type, acl, NULL);
287 }
288 
289 /*
290  * Most part of f2fs_acl_clone, f2fs_acl_create_masq, f2fs_acl_create
291  * are copied from posix_acl.c
292  */
293 static struct posix_acl *f2fs_acl_clone(const struct posix_acl *acl,
294 							gfp_t flags)
295 {
296 	struct posix_acl *clone = NULL;
297 
298 	if (acl) {
299 		int size = sizeof(struct posix_acl) + acl->a_count *
300 				sizeof(struct posix_acl_entry);
301 		clone = kmemdup(acl, size, flags);
302 		if (clone)
303 			refcount_set(&clone->a_refcount, 1);
304 	}
305 	return clone;
306 }
307 
308 static int f2fs_acl_create_masq(struct posix_acl *acl, umode_t *mode_p)
309 {
310 	struct posix_acl_entry *pa, *pe;
311 	struct posix_acl_entry *group_obj = NULL, *mask_obj = NULL;
312 	umode_t mode = *mode_p;
313 	int not_equiv = 0;
314 
315 	/* assert(atomic_read(acl->a_refcount) == 1); */
316 
317 	FOREACH_ACL_ENTRY(pa, acl, pe) {
318 		switch (pa->e_tag) {
319 		case ACL_USER_OBJ:
320 			pa->e_perm &= (mode >> 6) | ~S_IRWXO;
321 			mode &= (pa->e_perm << 6) | ~S_IRWXU;
322 			break;
323 
324 		case ACL_USER:
325 		case ACL_GROUP:
326 			not_equiv = 1;
327 			break;
328 
329 		case ACL_GROUP_OBJ:
330 			group_obj = pa;
331 			break;
332 
333 		case ACL_OTHER:
334 			pa->e_perm &= mode | ~S_IRWXO;
335 			mode &= pa->e_perm | ~S_IRWXO;
336 			break;
337 
338 		case ACL_MASK:
339 			mask_obj = pa;
340 			not_equiv = 1;
341 			break;
342 
343 		default:
344 			return -EIO;
345 		}
346 	}
347 
348 	if (mask_obj) {
349 		mask_obj->e_perm &= (mode >> 3) | ~S_IRWXO;
350 		mode &= (mask_obj->e_perm << 3) | ~S_IRWXG;
351 	} else {
352 		if (!group_obj)
353 			return -EIO;
354 		group_obj->e_perm &= (mode >> 3) | ~S_IRWXO;
355 		mode &= (group_obj->e_perm << 3) | ~S_IRWXG;
356 	}
357 
358 	*mode_p = (*mode_p & ~S_IRWXUGO) | mode;
359 	return not_equiv;
360 }
361 
362 static int f2fs_acl_create(struct inode *dir, umode_t *mode,
363 		struct posix_acl **default_acl, struct posix_acl **acl,
364 		struct page *dpage)
365 {
366 	struct posix_acl *p;
367 	struct posix_acl *clone;
368 	int ret;
369 
370 	*acl = NULL;
371 	*default_acl = NULL;
372 
373 	if (S_ISLNK(*mode) || !IS_POSIXACL(dir))
374 		return 0;
375 
376 	p = __f2fs_get_acl(dir, ACL_TYPE_DEFAULT, dpage);
377 	if (!p || p == ERR_PTR(-EOPNOTSUPP)) {
378 		*mode &= ~current_umask();
379 		return 0;
380 	}
381 	if (IS_ERR(p))
382 		return PTR_ERR(p);
383 
384 	clone = f2fs_acl_clone(p, GFP_NOFS);
385 	if (!clone) {
386 		ret = -ENOMEM;
387 		goto release_acl;
388 	}
389 
390 	ret = f2fs_acl_create_masq(clone, mode);
391 	if (ret < 0)
392 		goto release_clone;
393 
394 	if (ret == 0)
395 		posix_acl_release(clone);
396 	else
397 		*acl = clone;
398 
399 	if (!S_ISDIR(*mode))
400 		posix_acl_release(p);
401 	else
402 		*default_acl = p;
403 
404 	return 0;
405 
406 release_clone:
407 	posix_acl_release(clone);
408 release_acl:
409 	posix_acl_release(p);
410 	return ret;
411 }
412 
413 int f2fs_init_acl(struct inode *inode, struct inode *dir, struct page *ipage,
414 							struct page *dpage)
415 {
416 	struct posix_acl *default_acl = NULL, *acl = NULL;
417 	int error;
418 
419 	error = f2fs_acl_create(dir, &inode->i_mode, &default_acl, &acl, dpage);
420 	if (error)
421 		return error;
422 
423 	f2fs_mark_inode_dirty_sync(inode, true);
424 
425 	if (default_acl) {
426 		error = __f2fs_set_acl(NULL, inode, ACL_TYPE_DEFAULT, default_acl,
427 				       ipage);
428 		posix_acl_release(default_acl);
429 	} else {
430 		inode->i_default_acl = NULL;
431 	}
432 	if (acl) {
433 		if (!error)
434 			error = __f2fs_set_acl(NULL, inode, ACL_TYPE_ACCESS, acl,
435 					       ipage);
436 		posix_acl_release(acl);
437 	} else {
438 		inode->i_acl = NULL;
439 	}
440 
441 	return error;
442 }
443