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#include <linux/kernel.h>
13#include <linux/slab.h>
14#include <linux/fs.h>
15#include <linux/sched.h>
16#include <linux/time.h>
17#include <linux/crc32.h>
18#include <linux/jffs2.h>
19#include <linux/xattr.h>
20#include <linux/posix_acl_xattr.h>
21#include <linux/mtd/mtd.h>
22#include "nodelist.h"
23
24static size_t jffs2_acl_size(int count)
25{
26	if (count <= 4) {
27		return sizeof(struct jffs2_acl_header)
28		       + count * sizeof(struct jffs2_acl_entry_short);
29	} else {
30		return sizeof(struct jffs2_acl_header)
31		       + 4 * sizeof(struct jffs2_acl_entry_short)
32		       + (count - 4) * sizeof(struct jffs2_acl_entry);
33	}
34}
35
36static int jffs2_acl_count(size_t size)
37{
38	size_t s;
39
40	size -= sizeof(struct jffs2_acl_header);
41	if (size < 4 * sizeof(struct jffs2_acl_entry_short)) {
42		if (size % sizeof(struct jffs2_acl_entry_short))
43			return -1;
44		return size / sizeof(struct jffs2_acl_entry_short);
45	} else {
46		s = size - 4 * sizeof(struct jffs2_acl_entry_short);
47		if (s % sizeof(struct jffs2_acl_entry))
48			return -1;
49		return s / sizeof(struct jffs2_acl_entry) + 4;
50	}
51}
52
53static struct posix_acl *jffs2_acl_from_medium(void *value, size_t size)
54{
55	void *end = value + size;
56	struct jffs2_acl_header *header = value;
57	struct jffs2_acl_entry *entry;
58	struct posix_acl *acl;
59	uint32_t ver;
60	int i, count;
61
62	if (!value)
63		return NULL;
64	if (size < sizeof(struct jffs2_acl_header))
65		return ERR_PTR(-EINVAL);
66	ver = je32_to_cpu(header->a_version);
67	if (ver != JFFS2_ACL_VERSION) {
68		JFFS2_WARNING("Invalid ACL version. (=%u)\n", ver);
69		return ERR_PTR(-EINVAL);
70	}
71
72	value += sizeof(struct jffs2_acl_header);
73	count = jffs2_acl_count(size);
74	if (count < 0)
75		return ERR_PTR(-EINVAL);
76	if (count == 0)
77		return NULL;
78
79	acl = posix_acl_alloc(count, GFP_KERNEL);
80	if (!acl)
81		return ERR_PTR(-ENOMEM);
82
83	for (i=0; i < count; i++) {
84		entry = value;
85		if (value + sizeof(struct jffs2_acl_entry_short) > end)
86			goto fail;
87		acl->a_entries[i].e_tag = je16_to_cpu(entry->e_tag);
88		acl->a_entries[i].e_perm = je16_to_cpu(entry->e_perm);
89		switch (acl->a_entries[i].e_tag) {
90			case ACL_USER_OBJ:
91			case ACL_GROUP_OBJ:
92			case ACL_MASK:
93			case ACL_OTHER:
94				value += sizeof(struct jffs2_acl_entry_short);
95				acl->a_entries[i].e_id = ACL_UNDEFINED_ID;
96				break;
97
98			case ACL_USER:
99			case ACL_GROUP:
100				value += sizeof(struct jffs2_acl_entry);
101				if (value > end)
102					goto fail;
103				acl->a_entries[i].e_id = je32_to_cpu(entry->e_id);
104				break;
105
106			default:
107				goto fail;
108		}
109	}
110	if (value != end)
111		goto fail;
112	return acl;
113 fail:
114	posix_acl_release(acl);
115	return ERR_PTR(-EINVAL);
116}
117
118static void *jffs2_acl_to_medium(const struct posix_acl *acl, size_t *size)
119{
120	struct jffs2_acl_header *header;
121	struct jffs2_acl_entry *entry;
122	void *e;
123	size_t i;
124
125	*size = jffs2_acl_size(acl->a_count);
126	header = kmalloc(sizeof(*header) + acl->a_count * sizeof(*entry), GFP_KERNEL);
127	if (!header)
128		return ERR_PTR(-ENOMEM);
129	header->a_version = cpu_to_je32(JFFS2_ACL_VERSION);
130	e = header + 1;
131	for (i=0; i < acl->a_count; i++) {
132		entry = e;
133		entry->e_tag = cpu_to_je16(acl->a_entries[i].e_tag);
134		entry->e_perm = cpu_to_je16(acl->a_entries[i].e_perm);
135		switch(acl->a_entries[i].e_tag) {
136			case ACL_USER:
137			case ACL_GROUP:
138				entry->e_id = cpu_to_je32(acl->a_entries[i].e_id);
139				e += sizeof(struct jffs2_acl_entry);
140				break;
141
142			case ACL_USER_OBJ:
143			case ACL_GROUP_OBJ:
144			case ACL_MASK:
145			case ACL_OTHER:
146				e += sizeof(struct jffs2_acl_entry_short);
147				break;
148
149			default:
150				goto fail;
151		}
152	}
153	return header;
154 fail:
155	kfree(header);
156	return ERR_PTR(-EINVAL);
157}
158
159static struct posix_acl *jffs2_get_acl(struct inode *inode, int type)
160{
161	struct posix_acl *acl;
162	char *value = NULL;
163	int rc, xprefix;
164
165	acl = get_cached_acl(inode, type);
166	if (acl != ACL_NOT_CACHED)
167		return acl;
168
169	switch (type) {
170	case ACL_TYPE_ACCESS:
171		xprefix = JFFS2_XPREFIX_ACL_ACCESS;
172		break;
173	case ACL_TYPE_DEFAULT:
174		xprefix = JFFS2_XPREFIX_ACL_DEFAULT;
175		break;
176	default:
177		BUG();
178	}
179	rc = do_jffs2_getxattr(inode, xprefix, "", NULL, 0);
180	if (rc > 0) {
181		value = kmalloc(rc, GFP_KERNEL);
182		if (!value)
183			return ERR_PTR(-ENOMEM);
184		rc = do_jffs2_getxattr(inode, xprefix, "", value, rc);
185	}
186	if (rc > 0) {
187		acl = jffs2_acl_from_medium(value, rc);
188	} else if (rc == -ENODATA || rc == -ENOSYS) {
189		acl = NULL;
190	} else {
191		acl = ERR_PTR(rc);
192	}
193	if (value)
194		kfree(value);
195	if (!IS_ERR(acl))
196		set_cached_acl(inode, type, acl);
197	return acl;
198}
199
200static int __jffs2_set_acl(struct inode *inode, int xprefix, struct posix_acl *acl)
201{
202	char *value = NULL;
203	size_t size = 0;
204	int rc;
205
206	if (acl) {
207		value = jffs2_acl_to_medium(acl, &size);
208		if (IS_ERR(value))
209			return PTR_ERR(value);
210	}
211	rc = do_jffs2_setxattr(inode, xprefix, "", value, size, 0);
212	if (!value && rc == -ENODATA)
213		rc = 0;
214	kfree(value);
215
216	return rc;
217}
218
219static int jffs2_set_acl(struct inode *inode, int type, struct posix_acl *acl)
220{
221	int rc, xprefix;
222
223	if (S_ISLNK(inode->i_mode))
224		return -EOPNOTSUPP;
225
226	switch (type) {
227	case ACL_TYPE_ACCESS:
228		xprefix = JFFS2_XPREFIX_ACL_ACCESS;
229		if (acl) {
230			mode_t mode = inode->i_mode;
231			rc = posix_acl_equiv_mode(acl, &mode);
232			if (rc < 0)
233				return rc;
234			if (inode->i_mode != mode) {
235				struct iattr attr;
236
237				attr.ia_valid = ATTR_MODE | ATTR_CTIME;
238				attr.ia_mode = mode;
239				attr.ia_ctime = CURRENT_TIME_SEC;
240				rc = jffs2_do_setattr(inode, &attr);
241				if (rc < 0)
242					return rc;
243			}
244			if (rc == 0)
245				acl = NULL;
246		}
247		break;
248	case ACL_TYPE_DEFAULT:
249		xprefix = JFFS2_XPREFIX_ACL_DEFAULT;
250		if (!S_ISDIR(inode->i_mode))
251			return acl ? -EACCES : 0;
252		break;
253	default:
254		return -EINVAL;
255	}
256	rc = __jffs2_set_acl(inode, xprefix, acl);
257	if (!rc)
258		set_cached_acl(inode, type, acl);
259	return rc;
260}
261
262int jffs2_check_acl(struct inode *inode, int mask)
263{
264	struct posix_acl *acl;
265	int rc;
266
267	acl = jffs2_get_acl(inode, ACL_TYPE_ACCESS);
268	if (IS_ERR(acl))
269		return PTR_ERR(acl);
270	if (acl) {
271		rc = posix_acl_permission(inode, acl, mask);
272		posix_acl_release(acl);
273		return rc;
274	}
275	return -EAGAIN;
276}
277
278int jffs2_init_acl_pre(struct inode *dir_i, struct inode *inode, int *i_mode)
279{
280	struct posix_acl *acl, *clone;
281	int rc;
282
283	cache_no_acl(inode);
284
285	if (S_ISLNK(*i_mode))
286		return 0;	/* Symlink always has no-ACL */
287
288	acl = jffs2_get_acl(dir_i, ACL_TYPE_DEFAULT);
289	if (IS_ERR(acl))
290		return PTR_ERR(acl);
291
292	if (!acl) {
293		*i_mode &= ~current_umask();
294	} else {
295		if (S_ISDIR(*i_mode))
296			set_cached_acl(inode, ACL_TYPE_DEFAULT, acl);
297
298		clone = posix_acl_clone(acl, GFP_KERNEL);
299		if (!clone)
300			return -ENOMEM;
301		rc = posix_acl_create_masq(clone, (mode_t *)i_mode);
302		if (rc < 0) {
303			posix_acl_release(clone);
304			return rc;
305		}
306		if (rc > 0)
307			set_cached_acl(inode, ACL_TYPE_ACCESS, clone);
308
309		posix_acl_release(clone);
310	}
311	return 0;
312}
313
314int jffs2_init_acl_post(struct inode *inode)
315{
316	int rc;
317
318	if (inode->i_default_acl) {
319		rc = __jffs2_set_acl(inode, JFFS2_XPREFIX_ACL_DEFAULT, inode->i_default_acl);
320		if (rc)
321			return rc;
322	}
323
324	if (inode->i_acl) {
325		rc = __jffs2_set_acl(inode, JFFS2_XPREFIX_ACL_ACCESS, inode->i_acl);
326		if (rc)
327			return rc;
328	}
329
330	return 0;
331}
332
333int jffs2_acl_chmod(struct inode *inode)
334{
335	struct posix_acl *acl, *clone;
336	int rc;
337
338	if (S_ISLNK(inode->i_mode))
339		return -EOPNOTSUPP;
340	acl = jffs2_get_acl(inode, ACL_TYPE_ACCESS);
341	if (IS_ERR(acl) || !acl)
342		return PTR_ERR(acl);
343	clone = posix_acl_clone(acl, GFP_KERNEL);
344	posix_acl_release(acl);
345	if (!clone)
346		return -ENOMEM;
347	rc = posix_acl_chmod_masq(clone, inode->i_mode);
348	if (!rc)
349		rc = jffs2_set_acl(inode, ACL_TYPE_ACCESS, clone);
350	posix_acl_release(clone);
351	return rc;
352}
353
354static size_t jffs2_acl_access_listxattr(struct dentry *dentry, char *list,
355		size_t list_size, const char *name, size_t name_len, int type)
356{
357	const int retlen = sizeof(POSIX_ACL_XATTR_ACCESS);
358
359	if (list && retlen <= list_size)
360		strcpy(list, POSIX_ACL_XATTR_ACCESS);
361	return retlen;
362}
363
364static size_t jffs2_acl_default_listxattr(struct dentry *dentry, char *list,
365		size_t list_size, const char *name, size_t name_len, int type)
366{
367	const int retlen = sizeof(POSIX_ACL_XATTR_DEFAULT);
368
369	if (list && retlen <= list_size)
370		strcpy(list, POSIX_ACL_XATTR_DEFAULT);
371	return retlen;
372}
373
374static int jffs2_acl_getxattr(struct dentry *dentry, const char *name,
375		void *buffer, size_t size, int type)
376{
377	struct posix_acl *acl;
378	int rc;
379
380	if (name[0] != '\0')
381		return -EINVAL;
382
383	acl = jffs2_get_acl(dentry->d_inode, type);
384	if (IS_ERR(acl))
385		return PTR_ERR(acl);
386	if (!acl)
387		return -ENODATA;
388	rc = posix_acl_to_xattr(acl, buffer, size);
389	posix_acl_release(acl);
390
391	return rc;
392}
393
394static int jffs2_acl_setxattr(struct dentry *dentry, const char *name,
395		const void *value, size_t size, int flags, int type)
396{
397	struct posix_acl *acl;
398	int rc;
399
400	if (name[0] != '\0')
401		return -EINVAL;
402	if (!is_owner_or_cap(dentry->d_inode))
403		return -EPERM;
404
405	if (value) {
406		acl = posix_acl_from_xattr(value, size);
407		if (IS_ERR(acl))
408			return PTR_ERR(acl);
409		if (acl) {
410			rc = posix_acl_valid(acl);
411			if (rc)
412				goto out;
413		}
414	} else {
415		acl = NULL;
416	}
417	rc = jffs2_set_acl(dentry->d_inode, type, acl);
418 out:
419	posix_acl_release(acl);
420	return rc;
421}
422
423const struct xattr_handler jffs2_acl_access_xattr_handler = {
424	.prefix	= POSIX_ACL_XATTR_ACCESS,
425	.flags	= ACL_TYPE_DEFAULT,
426	.list	= jffs2_acl_access_listxattr,
427	.get	= jffs2_acl_getxattr,
428	.set	= jffs2_acl_setxattr,
429};
430
431const struct xattr_handler jffs2_acl_default_xattr_handler = {
432	.prefix	= POSIX_ACL_XATTR_DEFAULT,
433	.flags	= ACL_TYPE_DEFAULT,
434	.list	= jffs2_acl_default_listxattr,
435	.get	= jffs2_acl_getxattr,
436	.set	= jffs2_acl_setxattr,
437};
438