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
17static 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
29static 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
46static 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;
108fail:
109	posix_acl_release(acl);
110	return ERR_PTR(-EINVAL);
111}
112
113static 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
163fail:
164	kfree(f2fs_acl);
165	return ERR_PTR(-EINVAL);
166}
167
168static 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
199struct 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
207static 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 (!vfsgid_in_group_p(i_gid_into_vfsgid(idmap, inode)) &&
223	    !capable_wrt_inode_uidgid(idmap, inode, CAP_FSETID))
224		mode &= ~S_ISGID;
225	*mode_p = mode;
226	return 0;
227}
228
229static int __f2fs_set_acl(struct mnt_idmap *idmap,
230			struct inode *inode, int type,
231			struct posix_acl *acl, struct page *ipage)
232{
233	int name_index;
234	void *value = NULL;
235	size_t size = 0;
236	int error;
237	umode_t mode = inode->i_mode;
238
239	switch (type) {
240	case ACL_TYPE_ACCESS:
241		name_index = F2FS_XATTR_INDEX_POSIX_ACL_ACCESS;
242		if (acl && !ipage) {
243			error = f2fs_acl_update_mode(idmap, inode,
244								&mode, &acl);
245			if (error)
246				return error;
247			set_acl_inode(inode, mode);
248		}
249		break;
250
251	case ACL_TYPE_DEFAULT:
252		name_index = F2FS_XATTR_INDEX_POSIX_ACL_DEFAULT;
253		if (!S_ISDIR(inode->i_mode))
254			return acl ? -EACCES : 0;
255		break;
256
257	default:
258		return -EINVAL;
259	}
260
261	if (acl) {
262		value = f2fs_acl_to_disk(F2FS_I_SB(inode), acl, &size);
263		if (IS_ERR(value)) {
264			clear_inode_flag(inode, FI_ACL_MODE);
265			return PTR_ERR(value);
266		}
267	}
268
269	error = f2fs_setxattr(inode, name_index, "", value, size, ipage, 0);
270
271	kfree(value);
272	if (!error)
273		set_cached_acl(inode, type, acl);
274
275	clear_inode_flag(inode, FI_ACL_MODE);
276	return error;
277}
278
279int f2fs_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
280		 struct posix_acl *acl, int type)
281{
282	struct inode *inode = d_inode(dentry);
283
284	if (unlikely(f2fs_cp_error(F2FS_I_SB(inode))))
285		return -EIO;
286
287	return __f2fs_set_acl(idmap, inode, type, acl, NULL);
288}
289
290/*
291 * Most part of f2fs_acl_clone, f2fs_acl_create_masq, f2fs_acl_create
292 * are copied from posix_acl.c
293 */
294static struct posix_acl *f2fs_acl_clone(const struct posix_acl *acl,
295							gfp_t flags)
296{
297	struct posix_acl *clone = NULL;
298
299	if (acl) {
300		int size = sizeof(struct posix_acl) + acl->a_count *
301				sizeof(struct posix_acl_entry);
302		clone = kmemdup(acl, size, flags);
303		if (clone)
304			refcount_set(&clone->a_refcount, 1);
305	}
306	return clone;
307}
308
309static int f2fs_acl_create_masq(struct posix_acl *acl, umode_t *mode_p)
310{
311	struct posix_acl_entry *pa, *pe;
312	struct posix_acl_entry *group_obj = NULL, *mask_obj = NULL;
313	umode_t mode = *mode_p;
314	int not_equiv = 0;
315
316	/* assert(atomic_read(acl->a_refcount) == 1); */
317
318	FOREACH_ACL_ENTRY(pa, acl, pe) {
319		switch (pa->e_tag) {
320		case ACL_USER_OBJ:
321			pa->e_perm &= (mode >> 6) | ~S_IRWXO;
322			mode &= (pa->e_perm << 6) | ~S_IRWXU;
323			break;
324
325		case ACL_USER:
326		case ACL_GROUP:
327			not_equiv = 1;
328			break;
329
330		case ACL_GROUP_OBJ:
331			group_obj = pa;
332			break;
333
334		case ACL_OTHER:
335			pa->e_perm &= mode | ~S_IRWXO;
336			mode &= pa->e_perm | ~S_IRWXO;
337			break;
338
339		case ACL_MASK:
340			mask_obj = pa;
341			not_equiv = 1;
342			break;
343
344		default:
345			return -EIO;
346		}
347	}
348
349	if (mask_obj) {
350		mask_obj->e_perm &= (mode >> 3) | ~S_IRWXO;
351		mode &= (mask_obj->e_perm << 3) | ~S_IRWXG;
352	} else {
353		if (!group_obj)
354			return -EIO;
355		group_obj->e_perm &= (mode >> 3) | ~S_IRWXO;
356		mode &= (group_obj->e_perm << 3) | ~S_IRWXG;
357	}
358
359	*mode_p = (*mode_p & ~S_IRWXUGO) | mode;
360	return not_equiv;
361}
362
363static int f2fs_acl_create(struct inode *dir, umode_t *mode,
364		struct posix_acl **default_acl, struct posix_acl **acl,
365		struct page *dpage)
366{
367	struct posix_acl *p;
368	struct posix_acl *clone;
369	int ret;
370
371	*acl = NULL;
372	*default_acl = NULL;
373
374	if (S_ISLNK(*mode) || !IS_POSIXACL(dir))
375		return 0;
376
377	p = __f2fs_get_acl(dir, ACL_TYPE_DEFAULT, dpage);
378	if (!p || p == ERR_PTR(-EOPNOTSUPP)) {
379		*mode &= ~current_umask();
380		return 0;
381	}
382	if (IS_ERR(p))
383		return PTR_ERR(p);
384
385	clone = f2fs_acl_clone(p, GFP_NOFS);
386	if (!clone) {
387		ret = -ENOMEM;
388		goto release_acl;
389	}
390
391	ret = f2fs_acl_create_masq(clone, mode);
392	if (ret < 0)
393		goto release_clone;
394
395	if (ret == 0)
396		posix_acl_release(clone);
397	else
398		*acl = clone;
399
400	if (!S_ISDIR(*mode))
401		posix_acl_release(p);
402	else
403		*default_acl = p;
404
405	return 0;
406
407release_clone:
408	posix_acl_release(clone);
409release_acl:
410	posix_acl_release(p);
411	return ret;
412}
413
414int f2fs_init_acl(struct inode *inode, struct inode *dir, struct page *ipage,
415							struct page *dpage)
416{
417	struct posix_acl *default_acl = NULL, *acl = NULL;
418	int error;
419
420	error = f2fs_acl_create(dir, &inode->i_mode, &default_acl, &acl, dpage);
421	if (error)
422		return error;
423
424	f2fs_mark_inode_dirty_sync(inode, true);
425
426	if (default_acl) {
427		error = __f2fs_set_acl(NULL, inode, ACL_TYPE_DEFAULT, default_acl,
428				       ipage);
429		posix_acl_release(default_acl);
430	} else {
431		inode->i_default_acl = NULL;
432	}
433	if (acl) {
434		if (!error)
435			error = __f2fs_set_acl(NULL, inode, ACL_TYPE_ACCESS, acl,
436					       ipage);
437		posix_acl_release(acl);
438	} else {
439		inode->i_acl = NULL;
440	}
441
442	return error;
443}
444