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	s = size - 4 * sizeof(struct jffs2_acl_entry_short);
42	if (s < 0) {
43		if (size % sizeof(struct jffs2_acl_entry_short))
44			return -1;
45		return size / sizeof(struct jffs2_acl_entry_short);
46	} else {
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_iget_acl(struct inode *inode, struct posix_acl **i_acl)
160{
161	struct posix_acl *acl = JFFS2_ACL_NOT_CACHED;
162
163	spin_lock(&inode->i_lock);
164	if (*i_acl != JFFS2_ACL_NOT_CACHED)
165		acl = posix_acl_dup(*i_acl);
166	spin_unlock(&inode->i_lock);
167	return acl;
168}
169
170static void jffs2_iset_acl(struct inode *inode, struct posix_acl **i_acl, struct posix_acl *acl)
171{
172	spin_lock(&inode->i_lock);
173	if (*i_acl != JFFS2_ACL_NOT_CACHED)
174		posix_acl_release(*i_acl);
175	*i_acl = posix_acl_dup(acl);
176	spin_unlock(&inode->i_lock);
177}
178
179static struct posix_acl *jffs2_get_acl(struct inode *inode, int type)
180{
181	struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
182	struct posix_acl *acl;
183	char *value = NULL;
184	int rc, xprefix;
185
186	switch (type) {
187	case ACL_TYPE_ACCESS:
188		acl = jffs2_iget_acl(inode, &f->i_acl_access);
189		if (acl != JFFS2_ACL_NOT_CACHED)
190			return acl;
191		xprefix = JFFS2_XPREFIX_ACL_ACCESS;
192		break;
193	case ACL_TYPE_DEFAULT:
194		acl = jffs2_iget_acl(inode, &f->i_acl_default);
195		if (acl != JFFS2_ACL_NOT_CACHED)
196			return acl;
197		xprefix = JFFS2_XPREFIX_ACL_DEFAULT;
198		break;
199	default:
200		return ERR_PTR(-EINVAL);
201	}
202	rc = do_jffs2_getxattr(inode, xprefix, "", NULL, 0);
203	if (rc > 0) {
204		value = kmalloc(rc, GFP_KERNEL);
205		if (!value)
206			return ERR_PTR(-ENOMEM);
207		rc = do_jffs2_getxattr(inode, xprefix, "", value, rc);
208	}
209	if (rc > 0) {
210		acl = jffs2_acl_from_medium(value, rc);
211	} else if (rc == -ENODATA || rc == -ENOSYS) {
212		acl = NULL;
213	} else {
214		acl = ERR_PTR(rc);
215	}
216	if (value)
217		kfree(value);
218	if (!IS_ERR(acl)) {
219		switch (type) {
220		case ACL_TYPE_ACCESS:
221			jffs2_iset_acl(inode, &f->i_acl_access, acl);
222			break;
223		case ACL_TYPE_DEFAULT:
224			jffs2_iset_acl(inode, &f->i_acl_default, acl);
225			break;
226		}
227	}
228	return acl;
229}
230
231static int jffs2_set_acl(struct inode *inode, int type, struct posix_acl *acl)
232{
233	struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
234	size_t size = 0;
235	char *value = NULL;
236	int rc, xprefix;
237
238	if (S_ISLNK(inode->i_mode))
239		return -EOPNOTSUPP;
240
241	switch (type) {
242	case ACL_TYPE_ACCESS:
243		xprefix = JFFS2_XPREFIX_ACL_ACCESS;
244		if (acl) {
245			mode_t mode = inode->i_mode;
246			rc = posix_acl_equiv_mode(acl, &mode);
247			if (rc < 0)
248				return rc;
249			if (inode->i_mode != mode) {
250				inode->i_mode = mode;
251				jffs2_dirty_inode(inode);
252			}
253			if (rc == 0)
254				acl = NULL;
255		}
256		break;
257	case ACL_TYPE_DEFAULT:
258		xprefix = JFFS2_XPREFIX_ACL_DEFAULT;
259		if (!S_ISDIR(inode->i_mode))
260			return acl ? -EACCES : 0;
261		break;
262	default:
263		return -EINVAL;
264	}
265	if (acl) {
266		value = jffs2_acl_to_medium(acl, &size);
267		if (IS_ERR(value))
268			return PTR_ERR(value);
269	}
270
271	rc = do_jffs2_setxattr(inode, xprefix, "", value, size, 0);
272	if (!value && rc == -ENODATA)
273		rc = 0;
274	if (value)
275		kfree(value);
276	if (!rc) {
277		switch(type) {
278		case ACL_TYPE_ACCESS:
279			jffs2_iset_acl(inode, &f->i_acl_access, acl);
280			break;
281		case ACL_TYPE_DEFAULT:
282			jffs2_iset_acl(inode, &f->i_acl_default, acl);
283			break;
284		}
285	}
286	return rc;
287}
288
289static int jffs2_check_acl(struct inode *inode, int mask)
290{
291	struct posix_acl *acl;
292	int rc;
293
294	acl = jffs2_get_acl(inode, ACL_TYPE_ACCESS);
295	if (IS_ERR(acl))
296		return PTR_ERR(acl);
297	if (acl) {
298		rc = posix_acl_permission(inode, acl, mask);
299		posix_acl_release(acl);
300		return rc;
301	}
302	return -EAGAIN;
303}
304
305int jffs2_permission(struct inode *inode, int mask, struct nameidata *nd)
306{
307	return generic_permission(inode, mask, jffs2_check_acl);
308}
309
310int jffs2_init_acl(struct inode *inode, struct inode *dir)
311{
312	struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
313	struct posix_acl *acl = NULL, *clone;
314	mode_t mode;
315	int rc = 0;
316
317	f->i_acl_access = JFFS2_ACL_NOT_CACHED;
318	f->i_acl_default = JFFS2_ACL_NOT_CACHED;
319	if (!S_ISLNK(inode->i_mode)) {
320		acl = jffs2_get_acl(dir, ACL_TYPE_DEFAULT);
321		if (IS_ERR(acl))
322			return PTR_ERR(acl);
323		if (!acl)
324			inode->i_mode &= ~current->fs->umask;
325	}
326	if (acl) {
327		if (S_ISDIR(inode->i_mode)) {
328			rc = jffs2_set_acl(inode, ACL_TYPE_DEFAULT, acl);
329			if (rc)
330				goto cleanup;
331		}
332		clone = posix_acl_clone(acl, GFP_KERNEL);
333		rc = -ENOMEM;
334		if (!clone)
335			goto cleanup;
336		mode = inode->i_mode;
337		rc = posix_acl_create_masq(clone, &mode);
338		if (rc >= 0) {
339			inode->i_mode = mode;
340			if (rc > 0)
341				rc = jffs2_set_acl(inode, ACL_TYPE_ACCESS, clone);
342		}
343		posix_acl_release(clone);
344	}
345 cleanup:
346	posix_acl_release(acl);
347	return rc;
348}
349
350void jffs2_clear_acl(struct jffs2_inode_info *f)
351{
352	if (f->i_acl_access && f->i_acl_access != JFFS2_ACL_NOT_CACHED) {
353		posix_acl_release(f->i_acl_access);
354		f->i_acl_access = JFFS2_ACL_NOT_CACHED;
355	}
356	if (f->i_acl_default && f->i_acl_default != JFFS2_ACL_NOT_CACHED) {
357		posix_acl_release(f->i_acl_default);
358		f->i_acl_default = JFFS2_ACL_NOT_CACHED;
359	}
360}
361
362int jffs2_acl_chmod(struct inode *inode)
363{
364	struct posix_acl *acl, *clone;
365	int rc;
366
367	if (S_ISLNK(inode->i_mode))
368		return -EOPNOTSUPP;
369	acl = jffs2_get_acl(inode, ACL_TYPE_ACCESS);
370	if (IS_ERR(acl) || !acl)
371		return PTR_ERR(acl);
372	clone = posix_acl_clone(acl, GFP_KERNEL);
373	posix_acl_release(acl);
374	if (!clone)
375		return -ENOMEM;
376	rc = posix_acl_chmod_masq(clone, inode->i_mode);
377	if (!rc)
378		rc = jffs2_set_acl(inode, ACL_TYPE_ACCESS, clone);
379	posix_acl_release(clone);
380	return rc;
381}
382
383static size_t jffs2_acl_access_listxattr(struct inode *inode, char *list, size_t list_size,
384					 const char *name, size_t name_len)
385{
386	const int retlen = sizeof(POSIX_ACL_XATTR_ACCESS);
387
388	if (list && retlen <= list_size)
389		strcpy(list, POSIX_ACL_XATTR_ACCESS);
390	return retlen;
391}
392
393static size_t jffs2_acl_default_listxattr(struct inode *inode, char *list, size_t list_size,
394					  const char *name, size_t name_len)
395{
396	const int retlen = sizeof(POSIX_ACL_XATTR_DEFAULT);
397
398	if (list && retlen <= list_size)
399		strcpy(list, POSIX_ACL_XATTR_DEFAULT);
400	return retlen;
401}
402
403static int jffs2_acl_getxattr(struct inode *inode, int type, void *buffer, size_t size)
404{
405	struct posix_acl *acl;
406	int rc;
407
408	acl = jffs2_get_acl(inode, type);
409	if (IS_ERR(acl))
410		return PTR_ERR(acl);
411	if (!acl)
412		return -ENODATA;
413	rc = posix_acl_to_xattr(acl, buffer, size);
414	posix_acl_release(acl);
415
416	return rc;
417}
418
419static int jffs2_acl_access_getxattr(struct inode *inode, const char *name, void *buffer, size_t size)
420{
421	if (name[0] != '\0')
422		return -EINVAL;
423	return jffs2_acl_getxattr(inode, ACL_TYPE_ACCESS, buffer, size);
424}
425
426static int jffs2_acl_default_getxattr(struct inode *inode, const char *name, void *buffer, size_t size)
427{
428	if (name[0] != '\0')
429		return -EINVAL;
430	return jffs2_acl_getxattr(inode, ACL_TYPE_DEFAULT, buffer, size);
431}
432
433static int jffs2_acl_setxattr(struct inode *inode, int type, const void *value, size_t size)
434{
435	struct posix_acl *acl;
436	int rc;
437
438	if ((current->fsuid != inode->i_uid) && !capable(CAP_FOWNER))
439		return -EPERM;
440
441	if (value) {
442		acl = posix_acl_from_xattr(value, size);
443		if (IS_ERR(acl))
444			return PTR_ERR(acl);
445		if (acl) {
446			rc = posix_acl_valid(acl);
447			if (rc)
448				goto out;
449		}
450	} else {
451		acl = NULL;
452	}
453	rc = jffs2_set_acl(inode, type, acl);
454 out:
455	posix_acl_release(acl);
456	return rc;
457}
458
459static int jffs2_acl_access_setxattr(struct inode *inode, const char *name,
460				     const void *buffer, size_t size, int flags)
461{
462	if (name[0] != '\0')
463		return -EINVAL;
464	return jffs2_acl_setxattr(inode, ACL_TYPE_ACCESS, buffer, size);
465}
466
467static int jffs2_acl_default_setxattr(struct inode *inode, const char *name,
468				      const void *buffer, size_t size, int flags)
469{
470	if (name[0] != '\0')
471		return -EINVAL;
472	return jffs2_acl_setxattr(inode, ACL_TYPE_DEFAULT, buffer, size);
473}
474
475struct xattr_handler jffs2_acl_access_xattr_handler = {
476	.prefix	= POSIX_ACL_XATTR_ACCESS,
477	.list	= jffs2_acl_access_listxattr,
478	.get	= jffs2_acl_access_getxattr,
479	.set	= jffs2_acl_access_setxattr,
480};
481
482struct xattr_handler jffs2_acl_default_xattr_handler = {
483	.prefix	= POSIX_ACL_XATTR_DEFAULT,
484	.list	= jffs2_acl_default_listxattr,
485	.get	= jffs2_acl_default_getxattr,
486	.set	= jffs2_acl_default_setxattr,
487};
488