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