xref: /linux/fs/f2fs/acl.c (revision d8441523f21375b11a4593a2d89942b407bcb44f)
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 
f2fs_acl_size(int count)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 
f2fs_acl_count(size_t size)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 
f2fs_acl_from_disk(const char * value,size_t size)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 
f2fs_acl_to_disk(struct f2fs_sb_info * sbi,const struct posix_acl * acl,size_t * size)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 
__f2fs_get_acl(struct inode * inode,int type,struct folio * dfolio)168 static struct posix_acl *__f2fs_get_acl(struct inode *inode, int type,
169 						struct folio *dfolio)
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, dfolio);
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, dfolio);
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 
f2fs_get_acl(struct inode * inode,int type,bool rcu)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 
f2fs_acl_update_mode(struct mnt_idmap * idmap,struct inode * inode,umode_t * mode_p,struct posix_acl ** acl)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 
__f2fs_set_acl(struct mnt_idmap * idmap,struct inode * inode,int type,struct posix_acl * acl,struct folio * ifolio)228 static int __f2fs_set_acl(struct mnt_idmap *idmap,
229 			struct inode *inode, int type,
230 			struct posix_acl *acl, struct folio *ifolio)
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 && !ifolio) {
242 			error = f2fs_acl_update_mode(idmap, inode, &mode, &acl);
243 			if (error)
244 				return error;
245 			set_acl_inode(inode, mode);
246 		}
247 		break;
248 
249 	case ACL_TYPE_DEFAULT:
250 		name_index = F2FS_XATTR_INDEX_POSIX_ACL_DEFAULT;
251 		if (!S_ISDIR(inode->i_mode))
252 			return acl ? -EACCES : 0;
253 		break;
254 
255 	default:
256 		return -EINVAL;
257 	}
258 
259 	if (acl) {
260 		value = f2fs_acl_to_disk(F2FS_I_SB(inode), acl, &size);
261 		if (IS_ERR(value)) {
262 			clear_inode_flag(inode, FI_ACL_MODE);
263 			return PTR_ERR(value);
264 		}
265 	}
266 
267 	error = f2fs_setxattr(inode, name_index, "", value, size, ifolio, 0);
268 
269 	kfree(value);
270 	if (!error)
271 		set_cached_acl(inode, type, acl);
272 
273 	clear_inode_flag(inode, FI_ACL_MODE);
274 	return error;
275 }
276 
f2fs_set_acl(struct mnt_idmap * idmap,struct dentry * dentry,struct posix_acl * acl,int type)277 int f2fs_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
278 		 struct posix_acl *acl, int type)
279 {
280 	struct inode *inode = d_inode(dentry);
281 
282 	if (unlikely(f2fs_cp_error(F2FS_I_SB(inode))))
283 		return -EIO;
284 
285 	return __f2fs_set_acl(idmap, inode, type, acl, NULL);
286 }
287 
288 /*
289  * Most part of f2fs_acl_clone, f2fs_acl_create_masq, f2fs_acl_create
290  * are copied from posix_acl.c
291  */
f2fs_acl_clone(const struct posix_acl * acl,gfp_t flags)292 static struct posix_acl *f2fs_acl_clone(const struct posix_acl *acl,
293 							gfp_t flags)
294 {
295 	struct posix_acl *clone = NULL;
296 
297 	if (acl) {
298 		clone = kmemdup(acl, struct_size(acl, a_entries, acl->a_count),
299 				flags);
300 		if (clone)
301 			refcount_set(&clone->a_refcount, 1);
302 	}
303 	return clone;
304 }
305 
f2fs_acl_create_masq(struct posix_acl * acl,umode_t * mode_p)306 static int f2fs_acl_create_masq(struct posix_acl *acl, umode_t *mode_p)
307 {
308 	struct posix_acl_entry *pa, *pe;
309 	struct posix_acl_entry *group_obj = NULL, *mask_obj = NULL;
310 	umode_t mode = *mode_p;
311 	int not_equiv = 0;
312 
313 	/* assert(atomic_read(acl->a_refcount) == 1); */
314 
315 	FOREACH_ACL_ENTRY(pa, acl, pe) {
316 		switch (pa->e_tag) {
317 		case ACL_USER_OBJ:
318 			pa->e_perm &= (mode >> 6) | ~S_IRWXO;
319 			mode &= (pa->e_perm << 6) | ~S_IRWXU;
320 			break;
321 
322 		case ACL_USER:
323 		case ACL_GROUP:
324 			not_equiv = 1;
325 			break;
326 
327 		case ACL_GROUP_OBJ:
328 			group_obj = pa;
329 			break;
330 
331 		case ACL_OTHER:
332 			pa->e_perm &= mode | ~S_IRWXO;
333 			mode &= pa->e_perm | ~S_IRWXO;
334 			break;
335 
336 		case ACL_MASK:
337 			mask_obj = pa;
338 			not_equiv = 1;
339 			break;
340 
341 		default:
342 			return -EIO;
343 		}
344 	}
345 
346 	if (mask_obj) {
347 		mask_obj->e_perm &= (mode >> 3) | ~S_IRWXO;
348 		mode &= (mask_obj->e_perm << 3) | ~S_IRWXG;
349 	} else {
350 		if (!group_obj)
351 			return -EIO;
352 		group_obj->e_perm &= (mode >> 3) | ~S_IRWXO;
353 		mode &= (group_obj->e_perm << 3) | ~S_IRWXG;
354 	}
355 
356 	*mode_p = (*mode_p & ~S_IRWXUGO) | mode;
357 	return not_equiv;
358 }
359 
f2fs_acl_create(struct inode * dir,umode_t * mode,struct posix_acl ** default_acl,struct posix_acl ** acl,struct folio * dfolio)360 static int f2fs_acl_create(struct inode *dir, umode_t *mode,
361 		struct posix_acl **default_acl, struct posix_acl **acl,
362 		struct folio *dfolio)
363 {
364 	struct posix_acl *p;
365 	struct posix_acl *clone;
366 	int ret;
367 
368 	*acl = NULL;
369 	*default_acl = NULL;
370 
371 	if (S_ISLNK(*mode) || !IS_POSIXACL(dir))
372 		return 0;
373 
374 	p = __f2fs_get_acl(dir, ACL_TYPE_DEFAULT, dfolio);
375 	if (!p || p == ERR_PTR(-EOPNOTSUPP)) {
376 		*mode &= ~current_umask();
377 		return 0;
378 	}
379 	if (IS_ERR(p))
380 		return PTR_ERR(p);
381 
382 	clone = f2fs_acl_clone(p, GFP_NOFS);
383 	if (!clone) {
384 		ret = -ENOMEM;
385 		goto release_acl;
386 	}
387 
388 	ret = f2fs_acl_create_masq(clone, mode);
389 	if (ret < 0)
390 		goto release_clone;
391 
392 	if (ret == 0)
393 		posix_acl_release(clone);
394 	else
395 		*acl = clone;
396 
397 	if (!S_ISDIR(*mode))
398 		posix_acl_release(p);
399 	else
400 		*default_acl = p;
401 
402 	return 0;
403 
404 release_clone:
405 	posix_acl_release(clone);
406 release_acl:
407 	posix_acl_release(p);
408 	return ret;
409 }
410 
f2fs_init_acl(struct inode * inode,struct inode * dir,struct folio * ifolio,struct folio * dfolio)411 int f2fs_init_acl(struct inode *inode, struct inode *dir, struct folio *ifolio,
412 							struct folio *dfolio)
413 {
414 	struct posix_acl *default_acl = NULL, *acl = NULL;
415 	int error;
416 
417 	error = f2fs_acl_create(dir, &inode->i_mode, &default_acl, &acl, dfolio);
418 	if (error)
419 		return error;
420 
421 	f2fs_mark_inode_dirty_sync(inode, true);
422 
423 	if (default_acl) {
424 		error = __f2fs_set_acl(NULL, inode, ACL_TYPE_DEFAULT,
425 				default_acl, ifolio);
426 		posix_acl_release(default_acl);
427 	} else {
428 		inode->i_default_acl = NULL;
429 	}
430 	if (acl) {
431 		if (!error)
432 			error = __f2fs_set_acl(NULL, inode, ACL_TYPE_ACCESS,
433 					acl, ifolio);
434 		posix_acl_release(acl);
435 	} else {
436 		inode->i_acl = NULL;
437 	}
438 
439 	return error;
440 }
441