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
24 static 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
36 static 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
53 static 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
118 static 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
159 static 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
200 static 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
219 static 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;
238 attr.ia_mode = mode;
239 rc = jffs2_do_setattr(inode, &attr);
240 if (rc < 0)
241 return rc;
242 }
243 if (rc == 0)
244 acl = NULL;
245 }
246 break;
247 case ACL_TYPE_DEFAULT:
248 xprefix = JFFS2_XPREFIX_ACL_DEFAULT;
249 if (!S_ISDIR(inode->i_mode))
250 return acl ? -EACCES : 0;
251 break;
252 default:
253 return -EINVAL;
254 }
255 rc = __jffs2_set_acl(inode, xprefix, acl);
256 if (!rc)
257 set_cached_acl(inode, type, acl);
258 return rc;
259 }
260
261 static int jffs2_check_acl(struct inode *inode, int mask)
262 {
263 struct posix_acl *acl;
264 int rc;
265
266 acl = jffs2_get_acl(inode, ACL_TYPE_ACCESS);
267 if (IS_ERR(acl))
268 return PTR_ERR(acl);
269 if (acl) {
270 rc = posix_acl_permission(inode, acl, mask);
271 posix_acl_release(acl);
272 return rc;
273 }
274 return -EAGAIN;
275 }
276
277 int jffs2_permission(struct inode *inode, int mask)
278 {
279 return generic_permission(inode, mask, jffs2_check_acl);
280 }
281
282 int jffs2_init_acl_pre(struct inode *dir_i, struct inode *inode, int *i_mode)
283 {
284 struct posix_acl *acl, *clone;
285 int rc;
286
287 cache_no_acl(inode);
288
289 if (S_ISLNK(*i_mode))
290 return 0; /* Symlink always has no-ACL */
291
292 acl = jffs2_get_acl(dir_i, ACL_TYPE_DEFAULT);
293 if (IS_ERR(acl))
294 return PTR_ERR(acl);
295
296 if (!acl) {
297 *i_mode &= ~current_umask();
298 } else {
299 if (S_ISDIR(*i_mode))
300 set_cached_acl(inode, ACL_TYPE_DEFAULT, acl);
301
302 clone = posix_acl_clone(acl, GFP_KERNEL);
303 if (!clone)
304 return -ENOMEM;
305 rc = posix_acl_create_masq(clone, (mode_t *)i_mode);
306 if (rc < 0) {
307 posix_acl_release(clone);
308 return rc;
309 }
310 if (rc > 0)
311 set_cached_acl(inode, ACL_TYPE_ACCESS, clone);
312
313 posix_acl_release(clone);
314 }
315 return 0;
316 }
317
318 int jffs2_init_acl_post(struct inode *inode)
319 {
320 int rc;
321
322 if (inode->i_default_acl) {
323 rc = __jffs2_set_acl(inode, JFFS2_XPREFIX_ACL_DEFAULT, inode->i_default_acl);
324 if (rc)
325 return rc;
326 }
327
328 if (inode->i_acl) {
329 rc = __jffs2_set_acl(inode, JFFS2_XPREFIX_ACL_ACCESS, inode->i_acl);
330 if (rc)
331 return rc;
332 }
333
334 return 0;
335 }
336
337 int jffs2_acl_chmod(struct inode *inode)
338 {
339 struct posix_acl *acl, *clone;
340 int rc;
341
342 if (S_ISLNK(inode->i_mode))
343 return -EOPNOTSUPP;
344 acl = jffs2_get_acl(inode, ACL_TYPE_ACCESS);
345 if (IS_ERR(acl) || !acl)
346 return PTR_ERR(acl);
347 clone = posix_acl_clone(acl, GFP_KERNEL);
348 posix_acl_release(acl);
349 if (!clone)
350 return -ENOMEM;
351 rc = posix_acl_chmod_masq(clone, inode->i_mode);
352 if (!rc)
353 rc = jffs2_set_acl(inode, ACL_TYPE_ACCESS, clone);
354 posix_acl_release(clone);
355 return rc;
356 }
357
358 static size_t jffs2_acl_access_listxattr(struct inode *inode, char *list, size_t list_size,
359 const char *name, size_t name_len)
360 {
361 const int retlen = sizeof(POSIX_ACL_XATTR_ACCESS);
362
363 if (list && retlen <= list_size)
364 strcpy(list, POSIX_ACL_XATTR_ACCESS);
365 return retlen;
366 }
367
368 static size_t jffs2_acl_default_listxattr(struct inode *inode, char *list, size_t list_size,
369 const char *name, size_t name_len)
370 {
371 const int retlen = sizeof(POSIX_ACL_XATTR_DEFAULT);
372
373 if (list && retlen <= list_size)
374 strcpy(list, POSIX_ACL_XATTR_DEFAULT);
375 return retlen;
376 }
377
378 static int jffs2_acl_getxattr(struct inode *inode, int type, void *buffer, size_t size)
379 {
380 struct posix_acl *acl;
381 int rc;
382
383 acl = jffs2_get_acl(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
394 static int jffs2_acl_access_getxattr(struct inode *inode, const char *name, void *buffer, size_t size)
395 {
396 if (name[0] != '\0')
397 return -EINVAL;
398 return jffs2_acl_getxattr(inode, ACL_TYPE_ACCESS, buffer, size);
399 }
400
401 static int jffs2_acl_default_getxattr(struct inode *inode, const char *name, void *buffer, size_t size)
402 {
403 if (name[0] != '\0')
404 return -EINVAL;
405 return jffs2_acl_getxattr(inode, ACL_TYPE_DEFAULT, buffer, size);
406 }
407
408 static int jffs2_acl_setxattr(struct inode *inode, int type, const void *value, size_t size)
409 {
410 struct posix_acl *acl;
411 int rc;
412
413 if (!is_owner_or_cap(inode))
414 return -EPERM;
415
416 if (value) {
417 acl = posix_acl_from_xattr(value, size);
418 if (IS_ERR(acl))
419 return PTR_ERR(acl);
420 if (acl) {
421 rc = posix_acl_valid(acl);
422 if (rc)
423 goto out;
424 }
425 } else {
426 acl = NULL;
427 }
428 rc = jffs2_set_acl(inode, type, acl);
429 out:
430 posix_acl_release(acl);
431 return rc;
432 }
433
434 static int jffs2_acl_access_setxattr(struct inode *inode, const char *name,
435 const void *buffer, size_t size, int flags)
436 {
437 if (name[0] != '\0')
438 return -EINVAL;
439 return jffs2_acl_setxattr(inode, ACL_TYPE_ACCESS, buffer, size);
440 }
441
442 static int jffs2_acl_default_setxattr(struct inode *inode, const char *name,
443 const void *buffer, size_t size, int flags)
444 {
445 if (name[0] != '\0')
446 return -EINVAL;
447 return jffs2_acl_setxattr(inode, ACL_TYPE_DEFAULT, buffer, size);
448 }
449
450 struct xattr_handler jffs2_acl_access_xattr_handler = {
451 .prefix = POSIX_ACL_XATTR_ACCESS,
452 .list = jffs2_acl_access_listxattr,
453 .get = jffs2_acl_access_getxattr,
454 .set = jffs2_acl_access_setxattr,
455 };
456
457 struct xattr_handler jffs2_acl_default_xattr_handler = {
458 .prefix = POSIX_ACL_XATTR_DEFAULT,
459 .list = jffs2_acl_default_listxattr,
460 .get = jffs2_acl_default_getxattr,
461 .set = jffs2_acl_default_setxattr,
462 };
463
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