summaryrefslogtreecommitdiff
path: root/fs/jffs2/acl.c
blob: 7ebacf14837fd8ed1d47d1eec3f753e546de22bc (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
/*
 * JFFS2 -- Journalling Flash File System, Version 2.
 *
 * Copyright © 2006  NEC Corporation
 *
 * Created by KaiGai Kohei <kaigai@ak.jp.nec.com>
 *
 * For licensing information, see the file 'LICENCE' in this directory.
 *
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/fs.h>
#include <linux/sched.h>
#include <linux/time.h>
#include <linux/crc32.h>
#include <linux/jffs2.h>
#include <linux/xattr.h>
#include <linux/posix_acl_xattr.h>
#include <linux/mtd/mtd.h>
#include "nodelist.h"

static size_t jffs2_acl_size(int count)
{
	if (count <= 4) {
		return sizeof(struct jffs2_acl_header)
		       + count * sizeof(struct jffs2_acl_entry_short);
	} else {
		return sizeof(struct jffs2_acl_header)
		       + 4 * sizeof(struct jffs2_acl_entry_short)
		       + (count - 4) * sizeof(struct jffs2_acl_entry);
	}
}

static int jffs2_acl_count(size_t size)
{
	size_t s;

	size -= sizeof(struct jffs2_acl_header);
	if (size < 4 * sizeof(struct jffs2_acl_entry_short)) {
		if (size % sizeof(struct jffs2_acl_entry_short))
			return -1;
		return size / sizeof(struct jffs2_acl_entry_short);
	} else {
		s = size - 4 * sizeof(struct jffs2_acl_entry_short);
		if (s % sizeof(struct jffs2_acl_entry))
			return -1;
		return s / sizeof(struct jffs2_acl_entry) + 4;
	}
}

static struct posix_acl *jffs2_acl_from_medium(void *value, size_t size)
{
	void *end = value + size;
	struct jffs2_acl_header *header = value;
	struct jffs2_acl_entry *entry;
	struct posix_acl *acl;
	uint32_t ver;
	int i, count;

	if (!value)
		return NULL;
	if (size < sizeof(struct jffs2_acl_header))
		return ERR_PTR(-EINVAL);
	ver = je32_to_cpu(header->a_version);
	if (ver != JFFS2_ACL_VERSION) {
		JFFS2_WARNING("Invalid ACL version. (=%u)\n", ver);
		return ERR_PTR(-EINVAL);
	}

	value += sizeof(struct jffs2_acl_header);
	count = jffs2_acl_count(size);
	if (count < 0)
		return ERR_PTR(-EINVAL);
	if (count == 0)
		return NULL;

	acl = posix_acl_alloc(count, GFP_KERNEL);
	if (!acl)
		return ERR_PTR(-ENOMEM);

	for (i=0; i < count; i++) {
		entry = value;
		if (value + sizeof(struct jffs2_acl_entry_short) > end)
			goto fail;
		acl->a_entries[i].e_tag = je16_to_cpu(entry->e_tag);
		acl->a_entries[i].e_perm = je16_to_cpu(entry->e_perm);
		switch (acl->a_entries[i].e_tag) {
			case ACL_USER_OBJ:
			case ACL_GROUP_OBJ:
			case ACL_MASK:
			case ACL_OTHER:
				value += sizeof(struct jffs2_acl_entry_short);
				break;

			case ACL_USER:
				value += sizeof(struct jffs2_acl_entry);
				if (value > end)
					goto fail;
				acl->a_entries[i].e_uid =
					make_kuid(&init_user_ns,
						  je32_to_cpu(entry->e_id));
				break;
			case ACL_GROUP:
				value += sizeof(struct jffs2_acl_entry);
				if (value > end)
					goto fail;
				acl->a_entries[i].e_gid =
					make_kgid(&init_user_ns,
						  je32_to_cpu(entry->e_id));
				break;

			default:
				goto fail;
		}
	}
	if (value != end)
		goto fail;
	return acl;
 fail:
	posix_acl_release(acl);
	return ERR_PTR(-EINVAL);
}

static void *jffs2_acl_to_medium(const struct posix_acl *acl, size_t *size)
{
	struct jffs2_acl_header *header;
	struct jffs2_acl_entry *entry;
	void *e;
	size_t i;

	*size = jffs2_acl_size(acl->a_count);
	header = kmalloc(sizeof(*header) + acl->a_count * sizeof(*entry), GFP_KERNEL);
	if (!header)
		return ERR_PTR(-ENOMEM);
	header->a_version = cpu_to_je32(JFFS2_ACL_VERSION);
	e = header + 1;
	for (i=0; i < acl->a_count; i++) {
		const struct posix_acl_entry *acl_e = &acl->a_entries[i];
		entry = e;
		entry->e_tag = cpu_to_je16(acl_e->e_tag);
		entry->e_perm = cpu_to_je16(acl_e->e_perm);
		switch(acl_e->e_tag) {
			case ACL_USER:
				entry->e_id = cpu_to_je32(
					from_kuid(&init_user_ns, acl_e->e_uid));
				e += sizeof(struct jffs2_acl_entry);
				break;
			case ACL_GROUP:
				entry->e_id = cpu_to_je32(
					from_kgid(&init_user_ns, acl_e->e_gid));
				e += sizeof(struct jffs2_acl_entry);
				break;

			case ACL_USER_OBJ:
			case ACL_GROUP_OBJ:
			case ACL_MASK:
			case ACL_OTHER:
				e += sizeof(struct jffs2_acl_entry_short);
				break;

			default:
				goto fail;
		}
	}
	return header;
 fail:
	kfree(header);
	return ERR_PTR(-EINVAL);
}

struct posix_acl *jffs2_get_acl(struct inode *inode, int type)
{
	struct posix_acl *acl;
	char *value = NULL;
	int rc, xprefix;

	switch (type) {
	case ACL_TYPE_ACCESS:
		xprefix = JFFS2_XPREFIX_ACL_ACCESS;
		break;
	case ACL_TYPE_DEFAULT:
		xprefix = JFFS2_XPREFIX_ACL_DEFAULT;
		break;
	default:
		BUG();
	}
	rc = do_jffs2_getxattr(inode, xprefix, "", NULL, 0);
	if (rc > 0) {
		value = kmalloc(rc, GFP_KERNEL);
		if (!value)
			return ERR_PTR(-ENOMEM);
		rc = do_jffs2_getxattr(inode, xprefix, "", value, rc);
	}
	if (rc > 0) {
		acl = jffs2_acl_from_medium(value, rc);
	} else if (rc == -ENODATA || rc == -ENOSYS) {
		acl = NULL;
	} else {
		acl = ERR_PTR(rc);
	}
	kfree(value);
	return acl;
}

static int __jffs2_set_acl(struct inode *inode, int xprefix, struct posix_acl *acl)
{
	char *value = NULL;
	size_t size = 0;
	int rc;

	if (acl) {
		value = jffs2_acl_to_medium(acl, &size);
		if (IS_ERR(value))
			return PTR_ERR(value);
	}
	rc = do_jffs2_setxattr(inode, xprefix, "", value, size, 0);
	if (!value && rc == -ENODATA)
		rc = 0;
	kfree(value);

	return rc;
}

int jffs2_set_acl(struct inode *inode, struct posix_acl *acl, int type)
{
	int rc, xprefix;

	switch (type) {
	case ACL_TYPE_ACCESS:
		xprefix = JFFS2_XPREFIX_ACL_ACCESS;
		if (acl) {
			umode_t mode;

			rc = posix_acl_update_mode(inode, &mode, &acl);
			if (rc)
				return rc;
			if (inode->i_mode != mode) {
				struct iattr attr;

				attr.ia_valid = ATTR_MODE | ATTR_CTIME;
				attr.ia_mode = mode;
				attr.ia_ctime = current_time(inode);
				rc = jffs2_do_setattr(inode, &attr);
				if (rc < 0)
					return rc;
			}
		}
		break;
	case ACL_TYPE_DEFAULT:
		xprefix = JFFS2_XPREFIX_ACL_DEFAULT;
		if (!S_ISDIR(inode->i_mode))
			return acl ? -EACCES : 0;
		break;
	default:
		return -EINVAL;
	}
	rc = __jffs2_set_acl(inode, xprefix, acl);
	if (!rc)
		set_cached_acl(inode, type, acl);
	return rc;
}

int jffs2_init_acl_pre(struct inode *dir_i, struct inode *inode, umode_t *i_mode)
{
	struct posix_acl *default_acl, *acl;
	int rc;

	cache_no_acl(inode);

	rc = posix_acl_create(dir_i, i_mode, &default_acl, &acl);
	if (rc)
		return rc;

	if (default_acl) {
		set_cached_acl(inode, ACL_TYPE_DEFAULT, default_acl);
		posix_acl_release(default_acl);
	}
	if (acl) {
		set_cached_acl(inode, ACL_TYPE_ACCESS, acl);
		posix_acl_release(acl);
	}
	return 0;
}

int jffs2_init_acl_post(struct inode *inode)
{
	int rc;

	if (inode->i_default_acl) {
		rc = __jffs2_set_acl(inode, JFFS2_XPREFIX_ACL_DEFAULT, inode->i_default_acl);
		if (rc)
			return rc;
	}

	if (inode->i_acl) {
		rc = __jffs2_set_acl(inode, JFFS2_XPREFIX_ACL_ACCESS, inode->i_acl);
		if (rc)
			return rc;
	}

	return 0;
}