1/*
2 * JFFS2 -- Journalling Flash File System, Version 2.
3 *
4 * Copyright �� 2006  NEC Corporation
5 *
6 * Created by KaiGai Kohei <kaigai@ak.jp.nec.com>
7 *
8 * For licensing information, see the file 'LICENCE' in this directory.
9 *
10 */
11
12#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
13
14#include <linux/kernel.h>
15#include <linux/slab.h>
16#include <linux/fs.h>
17#include <linux/sched.h>
18#include <linux/time.h>
19#include <linux/crc32.h>
20#include <linux/jffs2.h>
21#include <linux/xattr.h>
22#include <linux/posix_acl_xattr.h>
23#include <linux/mtd/mtd.h>
24#include "nodelist.h"
25
26static size_t jffs2_acl_size(int count)
27{
28	if (count <= 4) {
29		return sizeof(struct jffs2_acl_header)
30		       + count * sizeof(struct jffs2_acl_entry_short);
31	} else {
32		return sizeof(struct jffs2_acl_header)
33		       + 4 * sizeof(struct jffs2_acl_entry_short)
34		       + (count - 4) * sizeof(struct jffs2_acl_entry);
35	}
36}
37
38static int jffs2_acl_count(size_t size)
39{
40	size_t s;
41
42	size -= sizeof(struct jffs2_acl_header);
43	if (size < 4 * sizeof(struct jffs2_acl_entry_short)) {
44		if (size % sizeof(struct jffs2_acl_entry_short))
45			return -1;
46		return size / sizeof(struct jffs2_acl_entry_short);
47	} else {
48		s = size - 4 * sizeof(struct jffs2_acl_entry_short);
49		if (s % sizeof(struct jffs2_acl_entry))
50			return -1;
51		return s / sizeof(struct jffs2_acl_entry) + 4;
52	}
53}
54
55static struct posix_acl *jffs2_acl_from_medium(void *value, size_t size)
56{
57	void *end = value + size;
58	struct jffs2_acl_header *header = value;
59	struct jffs2_acl_entry *entry;
60	struct posix_acl *acl;
61	uint32_t ver;
62	int i, count;
63
64	if (!value)
65		return NULL;
66	if (size < sizeof(struct jffs2_acl_header))
67		return ERR_PTR(-EINVAL);
68	ver = je32_to_cpu(header->a_version);
69	if (ver != JFFS2_ACL_VERSION) {
70		JFFS2_WARNING("Invalid ACL version. (=%u)\n", ver);
71		return ERR_PTR(-EINVAL);
72	}
73
74	value += sizeof(struct jffs2_acl_header);
75	count = jffs2_acl_count(size);
76	if (count < 0)
77		return ERR_PTR(-EINVAL);
78	if (count == 0)
79		return NULL;
80
81	acl = posix_acl_alloc(count, GFP_KERNEL);
82	if (!acl)
83		return ERR_PTR(-ENOMEM);
84
85	for (i=0; i < count; i++) {
86		entry = value;
87		if (value + sizeof(struct jffs2_acl_entry_short) > end)
88			goto fail;
89		acl->a_entries[i].e_tag = je16_to_cpu(entry->e_tag);
90		acl->a_entries[i].e_perm = je16_to_cpu(entry->e_perm);
91		switch (acl->a_entries[i].e_tag) {
92			case ACL_USER_OBJ:
93			case ACL_GROUP_OBJ:
94			case ACL_MASK:
95			case ACL_OTHER:
96				value += sizeof(struct jffs2_acl_entry_short);
97				break;
98
99			case ACL_USER:
100				value += sizeof(struct jffs2_acl_entry);
101				if (value > end)
102					goto fail;
103				acl->a_entries[i].e_uid =
104					make_kuid(&init_user_ns,
105						  je32_to_cpu(entry->e_id));
106				break;
107			case ACL_GROUP:
108				value += sizeof(struct jffs2_acl_entry);
109				if (value > end)
110					goto fail;
111				acl->a_entries[i].e_gid =
112					make_kgid(&init_user_ns,
113						  je32_to_cpu(entry->e_id));
114				break;
115
116			default:
117				goto fail;
118		}
119	}
120	if (value != end)
121		goto fail;
122	return acl;
123 fail:
124	posix_acl_release(acl);
125	return ERR_PTR(-EINVAL);
126}
127
128static void *jffs2_acl_to_medium(const struct posix_acl *acl, size_t *size)
129{
130	struct jffs2_acl_header *header;
131	struct jffs2_acl_entry *entry;
132	void *e;
133	size_t i;
134
135	*size = jffs2_acl_size(acl->a_count);
136	header = kmalloc(sizeof(*header) + acl->a_count * sizeof(*entry), GFP_KERNEL);
137	if (!header)
138		return ERR_PTR(-ENOMEM);
139	header->a_version = cpu_to_je32(JFFS2_ACL_VERSION);
140	e = header + 1;
141	for (i=0; i < acl->a_count; i++) {
142		const struct posix_acl_entry *acl_e = &acl->a_entries[i];
143		entry = e;
144		entry->e_tag = cpu_to_je16(acl_e->e_tag);
145		entry->e_perm = cpu_to_je16(acl_e->e_perm);
146		switch(acl_e->e_tag) {
147			case ACL_USER:
148				entry->e_id = cpu_to_je32(
149					from_kuid(&init_user_ns, acl_e->e_uid));
150				e += sizeof(struct jffs2_acl_entry);
151				break;
152			case ACL_GROUP:
153				entry->e_id = cpu_to_je32(
154					from_kgid(&init_user_ns, acl_e->e_gid));
155				e += sizeof(struct jffs2_acl_entry);
156				break;
157
158			case ACL_USER_OBJ:
159			case ACL_GROUP_OBJ:
160			case ACL_MASK:
161			case ACL_OTHER:
162				e += sizeof(struct jffs2_acl_entry_short);
163				break;
164
165			default:
166				goto fail;
167		}
168	}
169	return header;
170 fail:
171	kfree(header);
172	return ERR_PTR(-EINVAL);
173}
174
175struct posix_acl *jffs2_get_acl(struct inode *inode, int type)
176{
177	struct posix_acl *acl;
178	char *value = NULL;
179	int rc, xprefix;
180
181	switch (type) {
182	case ACL_TYPE_ACCESS:
183		xprefix = JFFS2_XPREFIX_ACL_ACCESS;
184		break;
185	case ACL_TYPE_DEFAULT:
186		xprefix = JFFS2_XPREFIX_ACL_DEFAULT;
187		break;
188	default:
189		BUG();
190	}
191	rc = do_jffs2_getxattr(inode, xprefix, "", NULL, 0);
192	if (rc > 0) {
193		value = kmalloc(rc, GFP_KERNEL);
194		if (!value)
195			return ERR_PTR(-ENOMEM);
196		rc = do_jffs2_getxattr(inode, xprefix, "", value, rc);
197	}
198	if (rc > 0) {
199		acl = jffs2_acl_from_medium(value, rc);
200	} else if (rc == -ENODATA || rc == -ENOSYS) {
201		acl = NULL;
202	} else {
203		acl = ERR_PTR(rc);
204	}
205	kfree(value);
206	if (!IS_ERR(acl))
207		set_cached_acl(inode, type, acl);
208	return acl;
209}
210
211static int __jffs2_set_acl(struct inode *inode, int xprefix, struct posix_acl *acl)
212{
213	char *value = NULL;
214	size_t size = 0;
215	int rc;
216
217	if (acl) {
218		value = jffs2_acl_to_medium(acl, &size);
219		if (IS_ERR(value))
220			return PTR_ERR(value);
221	}
222	rc = do_jffs2_setxattr(inode, xprefix, "", value, size, 0);
223	if (!value && rc == -ENODATA)
224		rc = 0;
225	kfree(value);
226
227	return rc;
228}
229
230int jffs2_set_acl(struct inode *inode, struct posix_acl *acl, int type)
231{
232	int rc, xprefix;
233
234	switch (type) {
235	case ACL_TYPE_ACCESS:
236		xprefix = JFFS2_XPREFIX_ACL_ACCESS;
237		if (acl) {
238			umode_t mode = inode->i_mode;
239			rc = posix_acl_equiv_mode(acl, &mode);
240			if (rc < 0)
241				return rc;
242			if (inode->i_mode != mode) {
243				struct iattr attr;
244
245				attr.ia_valid = ATTR_MODE | ATTR_CTIME;
246				attr.ia_mode = mode;
247				attr.ia_ctime = CURRENT_TIME_SEC;
248				rc = jffs2_do_setattr(inode, &attr);
249				if (rc < 0)
250					return rc;
251			}
252			if (rc == 0)
253				acl = NULL;
254		}
255		break;
256	case ACL_TYPE_DEFAULT:
257		xprefix = JFFS2_XPREFIX_ACL_DEFAULT;
258		if (!S_ISDIR(inode->i_mode))
259			return acl ? -EACCES : 0;
260		break;
261	default:
262		return -EINVAL;
263	}
264	rc = __jffs2_set_acl(inode, xprefix, acl);
265	if (!rc)
266		set_cached_acl(inode, type, acl);
267	return rc;
268}
269
270int jffs2_init_acl_pre(struct inode *dir_i, struct inode *inode, umode_t *i_mode)
271{
272	struct posix_acl *default_acl, *acl;
273	int rc;
274
275	cache_no_acl(inode);
276
277	rc = posix_acl_create(dir_i, i_mode, &default_acl, &acl);
278	if (rc)
279		return rc;
280
281	if (default_acl) {
282		set_cached_acl(inode, ACL_TYPE_DEFAULT, default_acl);
283		posix_acl_release(default_acl);
284	}
285	if (acl) {
286		set_cached_acl(inode, ACL_TYPE_ACCESS, acl);
287		posix_acl_release(acl);
288	}
289	return 0;
290}
291
292int jffs2_init_acl_post(struct inode *inode)
293{
294	int rc;
295
296	if (inode->i_default_acl) {
297		rc = __jffs2_set_acl(inode, JFFS2_XPREFIX_ACL_DEFAULT, inode->i_default_acl);
298		if (rc)
299			return rc;
300	}
301
302	if (inode->i_acl) {
303		rc = __jffs2_set_acl(inode, JFFS2_XPREFIX_ACL_ACCESS, inode->i_acl);
304		if (rc)
305			return rc;
306	}
307
308	return 0;
309}
310