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
jffs2_acl_size(int count)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
jffs2_acl_count(size_t size)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
jffs2_acl_from_medium(void * value,size_t size)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
jffs2_acl_to_medium(const struct posix_acl * acl,size_t * size)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
jffs2_get_acl(struct inode * inode,int type)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
__jffs2_set_acl(struct inode * inode,int xprefix,struct posix_acl * acl)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
jffs2_set_acl(struct inode * inode,int type,struct posix_acl * acl)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 | 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
jffs2_check_acl(struct inode * inode,int mask,unsigned int flags)262 int jffs2_check_acl(struct inode *inode, int mask, unsigned int flags)
263 {
264 struct posix_acl *acl;
265 int rc;
266
267 if (flags & IPERM_FLAG_RCU)
268 return -ECHILD;
269
270 acl = jffs2_get_acl(inode, ACL_TYPE_ACCESS);
271 if (IS_ERR(acl))
272 return PTR_ERR(acl);
273 if (acl) {
274 rc = posix_acl_permission(inode, acl, mask);
275 posix_acl_release(acl);
276 return rc;
277 }
278 return -EAGAIN;
279 }
280
jffs2_init_acl_pre(struct inode * dir_i,struct inode * inode,int * i_mode)281 int jffs2_init_acl_pre(struct inode *dir_i, struct inode *inode, int *i_mode)
282 {
283 struct posix_acl *acl, *clone;
284 int rc;
285
286 cache_no_acl(inode);
287
288 if (S_ISLNK(*i_mode))
289 return 0; /* Symlink always has no-ACL */
290
291 acl = jffs2_get_acl(dir_i, ACL_TYPE_DEFAULT);
292 if (IS_ERR(acl))
293 return PTR_ERR(acl);
294
295 if (!acl) {
296 *i_mode &= ~current_umask();
297 } else {
298 if (S_ISDIR(*i_mode))
299 set_cached_acl(inode, ACL_TYPE_DEFAULT, acl);
300
301 clone = posix_acl_clone(acl, GFP_KERNEL);
302 if (!clone)
303 return -ENOMEM;
304 rc = posix_acl_create_masq(clone, (mode_t *)i_mode);
305 if (rc < 0) {
306 posix_acl_release(clone);
307 return rc;
308 }
309 if (rc > 0)
310 set_cached_acl(inode, ACL_TYPE_ACCESS, clone);
311
312 posix_acl_release(clone);
313 }
314 return 0;
315 }
316
jffs2_init_acl_post(struct inode * inode)317 int jffs2_init_acl_post(struct inode *inode)
318 {
319 int rc;
320
321 if (inode->i_default_acl) {
322 rc = __jffs2_set_acl(inode, JFFS2_XPREFIX_ACL_DEFAULT, inode->i_default_acl);
323 if (rc)
324 return rc;
325 }
326
327 if (inode->i_acl) {
328 rc = __jffs2_set_acl(inode, JFFS2_XPREFIX_ACL_ACCESS, inode->i_acl);
329 if (rc)
330 return rc;
331 }
332
333 return 0;
334 }
335
jffs2_acl_chmod(struct inode * inode)336 int jffs2_acl_chmod(struct inode *inode)
337 {
338 struct posix_acl *acl, *clone;
339 int rc;
340
341 if (S_ISLNK(inode->i_mode))
342 return -EOPNOTSUPP;
343 acl = jffs2_get_acl(inode, ACL_TYPE_ACCESS);
344 if (IS_ERR(acl) || !acl)
345 return PTR_ERR(acl);
346 clone = posix_acl_clone(acl, GFP_KERNEL);
347 posix_acl_release(acl);
348 if (!clone)
349 return -ENOMEM;
350 rc = posix_acl_chmod_masq(clone, inode->i_mode);
351 if (!rc)
352 rc = jffs2_set_acl(inode, ACL_TYPE_ACCESS, clone);
353 posix_acl_release(clone);
354 return rc;
355 }
356
jffs2_acl_access_listxattr(struct dentry * dentry,char * list,size_t list_size,const char * name,size_t name_len,int type)357 static size_t jffs2_acl_access_listxattr(struct dentry *dentry, char *list,
358 size_t list_size, const char *name, size_t name_len, int type)
359 {
360 const int retlen = sizeof(POSIX_ACL_XATTR_ACCESS);
361
362 if (list && retlen <= list_size)
363 strcpy(list, POSIX_ACL_XATTR_ACCESS);
364 return retlen;
365 }
366
jffs2_acl_default_listxattr(struct dentry * dentry,char * list,size_t list_size,const char * name,size_t name_len,int type)367 static size_t jffs2_acl_default_listxattr(struct dentry *dentry, char *list,
368 size_t list_size, const char *name, size_t name_len, int type)
369 {
370 const int retlen = sizeof(POSIX_ACL_XATTR_DEFAULT);
371
372 if (list && retlen <= list_size)
373 strcpy(list, POSIX_ACL_XATTR_DEFAULT);
374 return retlen;
375 }
376
jffs2_acl_getxattr(struct dentry * dentry,const char * name,void * buffer,size_t size,int type)377 static int jffs2_acl_getxattr(struct dentry *dentry, const char *name,
378 void *buffer, size_t size, int type)
379 {
380 struct posix_acl *acl;
381 int rc;
382
383 if (name[0] != '\0')
384 return -EINVAL;
385
386 acl = jffs2_get_acl(dentry->d_inode, type);
387 if (IS_ERR(acl))
388 return PTR_ERR(acl);
389 if (!acl)
390 return -ENODATA;
391 rc = posix_acl_to_xattr(acl, buffer, size);
392 posix_acl_release(acl);
393
394 return rc;
395 }
396
jffs2_acl_setxattr(struct dentry * dentry,const char * name,const void * value,size_t size,int flags,int type)397 static int jffs2_acl_setxattr(struct dentry *dentry, const char *name,
398 const void *value, size_t size, int flags, int type)
399 {
400 struct posix_acl *acl;
401 int rc;
402
403 if (name[0] != '\0')
404 return -EINVAL;
405 if (!inode_owner_or_capable(dentry->d_inode))
406 return -EPERM;
407
408 if (value) {
409 acl = posix_acl_from_xattr(value, size);
410 if (IS_ERR(acl))
411 return PTR_ERR(acl);
412 if (acl) {
413 rc = posix_acl_valid(acl);
414 if (rc)
415 goto out;
416 }
417 } else {
418 acl = NULL;
419 }
420 rc = jffs2_set_acl(dentry->d_inode, type, acl);
421 out:
422 posix_acl_release(acl);
423 return rc;
424 }
425
426 const struct xattr_handler jffs2_acl_access_xattr_handler = {
427 .prefix = POSIX_ACL_XATTR_ACCESS,
428 .flags = ACL_TYPE_DEFAULT,
429 .list = jffs2_acl_access_listxattr,
430 .get = jffs2_acl_getxattr,
431 .set = jffs2_acl_setxattr,
432 };
433
434 const struct xattr_handler jffs2_acl_default_xattr_handler = {
435 .prefix = POSIX_ACL_XATTR_DEFAULT,
436 .flags = ACL_TYPE_DEFAULT,
437 .list = jffs2_acl_default_listxattr,
438 .get = jffs2_acl_getxattr,
439 .set = jffs2_acl_setxattr,
440 };
441