Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm...
[linux-3.10.git] / fs / jffs2 / acl.c
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
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
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
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                                 break;
98
99                         case ACL_USER:
100                                 value += sizeof(struct jffs2_acl_entry);
101                                 if (value > end)
102                                         goto fail;
103                                 acl->a_entries[i].e_uid =
104                                         make_kuid(&init_user_ns,
105                                                   je32_to_cpu(entry->e_id));
106                                 break;
107                         case ACL_GROUP:
108                                 value += sizeof(struct jffs2_acl_entry);
109                                 if (value > end)
110                                         goto fail;
111                                 acl->a_entries[i].e_gid =
112                                         make_kgid(&init_user_ns,
113                                                   je32_to_cpu(entry->e_id));
114                                 break;
115
116                         default:
117                                 goto fail;
118                 }
119         }
120         if (value != end)
121                 goto fail;
122         return acl;
123  fail:
124         posix_acl_release(acl);
125         return ERR_PTR(-EINVAL);
126 }
127
128 static void *jffs2_acl_to_medium(const struct posix_acl *acl, size_t *size)
129 {
130         struct jffs2_acl_header *header;
131         struct jffs2_acl_entry *entry;
132         void *e;
133         size_t i;
134
135         *size = jffs2_acl_size(acl->a_count);
136         header = kmalloc(sizeof(*header) + acl->a_count * sizeof(*entry), GFP_KERNEL);
137         if (!header)
138                 return ERR_PTR(-ENOMEM);
139         header->a_version = cpu_to_je32(JFFS2_ACL_VERSION);
140         e = header + 1;
141         for (i=0; i < acl->a_count; i++) {
142                 const struct posix_acl_entry *acl_e = &acl->a_entries[i];
143                 entry = e;
144                 entry->e_tag = cpu_to_je16(acl_e->e_tag);
145                 entry->e_perm = cpu_to_je16(acl_e->e_perm);
146                 switch(acl_e->e_tag) {
147                         case ACL_USER:
148                                 entry->e_id = cpu_to_je32(
149                                         from_kuid(&init_user_ns, acl_e->e_uid));
150                                 e += sizeof(struct jffs2_acl_entry);
151                                 break;
152                         case ACL_GROUP:
153                                 entry->e_id = cpu_to_je32(
154                                         from_kgid(&init_user_ns, acl_e->e_gid));
155                                 e += sizeof(struct jffs2_acl_entry);
156                                 break;
157
158                         case ACL_USER_OBJ:
159                         case ACL_GROUP_OBJ:
160                         case ACL_MASK:
161                         case ACL_OTHER:
162                                 e += sizeof(struct jffs2_acl_entry_short);
163                                 break;
164
165                         default:
166                                 goto fail;
167                 }
168         }
169         return header;
170  fail:
171         kfree(header);
172         return ERR_PTR(-EINVAL);
173 }
174
175 struct posix_acl *jffs2_get_acl(struct inode *inode, int type)
176 {
177         struct posix_acl *acl;
178         char *value = NULL;
179         int rc, xprefix;
180
181         acl = get_cached_acl(inode, type);
182         if (acl != ACL_NOT_CACHED)
183                 return acl;
184
185         switch (type) {
186         case ACL_TYPE_ACCESS:
187                 xprefix = JFFS2_XPREFIX_ACL_ACCESS;
188                 break;
189         case ACL_TYPE_DEFAULT:
190                 xprefix = JFFS2_XPREFIX_ACL_DEFAULT;
191                 break;
192         default:
193                 BUG();
194         }
195         rc = do_jffs2_getxattr(inode, xprefix, "", NULL, 0);
196         if (rc > 0) {
197                 value = kmalloc(rc, GFP_KERNEL);
198                 if (!value)
199                         return ERR_PTR(-ENOMEM);
200                 rc = do_jffs2_getxattr(inode, xprefix, "", value, rc);
201         }
202         if (rc > 0) {
203                 acl = jffs2_acl_from_medium(value, rc);
204         } else if (rc == -ENODATA || rc == -ENOSYS) {
205                 acl = NULL;
206         } else {
207                 acl = ERR_PTR(rc);
208         }
209         if (value)
210                 kfree(value);
211         if (!IS_ERR(acl))
212                 set_cached_acl(inode, type, acl);
213         return acl;
214 }
215
216 static int __jffs2_set_acl(struct inode *inode, int xprefix, struct posix_acl *acl)
217 {
218         char *value = NULL;
219         size_t size = 0;
220         int rc;
221
222         if (acl) {
223                 value = jffs2_acl_to_medium(acl, &size);
224                 if (IS_ERR(value))
225                         return PTR_ERR(value);
226         }
227         rc = do_jffs2_setxattr(inode, xprefix, "", value, size, 0);
228         if (!value && rc == -ENODATA)
229                 rc = 0;
230         kfree(value);
231
232         return rc;
233 }
234
235 static int jffs2_set_acl(struct inode *inode, int type, struct posix_acl *acl)
236 {
237         int rc, xprefix;
238
239         if (S_ISLNK(inode->i_mode))
240                 return -EOPNOTSUPP;
241
242         switch (type) {
243         case ACL_TYPE_ACCESS:
244                 xprefix = JFFS2_XPREFIX_ACL_ACCESS;
245                 if (acl) {
246                         umode_t mode = inode->i_mode;
247                         rc = posix_acl_equiv_mode(acl, &mode);
248                         if (rc < 0)
249                                 return rc;
250                         if (inode->i_mode != mode) {
251                                 struct iattr attr;
252
253                                 attr.ia_valid = ATTR_MODE | ATTR_CTIME;
254                                 attr.ia_mode = mode;
255                                 attr.ia_ctime = CURRENT_TIME_SEC;
256                                 rc = jffs2_do_setattr(inode, &attr);
257                                 if (rc < 0)
258                                         return rc;
259                         }
260                         if (rc == 0)
261                                 acl = NULL;
262                 }
263                 break;
264         case ACL_TYPE_DEFAULT:
265                 xprefix = JFFS2_XPREFIX_ACL_DEFAULT;
266                 if (!S_ISDIR(inode->i_mode))
267                         return acl ? -EACCES : 0;
268                 break;
269         default:
270                 return -EINVAL;
271         }
272         rc = __jffs2_set_acl(inode, xprefix, acl);
273         if (!rc)
274                 set_cached_acl(inode, type, acl);
275         return rc;
276 }
277
278 int jffs2_init_acl_pre(struct inode *dir_i, struct inode *inode, umode_t *i_mode)
279 {
280         struct posix_acl *acl;
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                 rc = posix_acl_create(&acl, GFP_KERNEL, i_mode);
299                 if (rc < 0)
300                         return rc;
301                 if (rc > 0)
302                         set_cached_acl(inode, ACL_TYPE_ACCESS, acl);
303
304                 posix_acl_release(acl);
305         }
306         return 0;
307 }
308
309 int jffs2_init_acl_post(struct inode *inode)
310 {
311         int rc;
312
313         if (inode->i_default_acl) {
314                 rc = __jffs2_set_acl(inode, JFFS2_XPREFIX_ACL_DEFAULT, inode->i_default_acl);
315                 if (rc)
316                         return rc;
317         }
318
319         if (inode->i_acl) {
320                 rc = __jffs2_set_acl(inode, JFFS2_XPREFIX_ACL_ACCESS, inode->i_acl);
321                 if (rc)
322                         return rc;
323         }
324
325         return 0;
326 }
327
328 int jffs2_acl_chmod(struct inode *inode)
329 {
330         struct posix_acl *acl;
331         int rc;
332
333         if (S_ISLNK(inode->i_mode))
334                 return -EOPNOTSUPP;
335         acl = jffs2_get_acl(inode, ACL_TYPE_ACCESS);
336         if (IS_ERR(acl) || !acl)
337                 return PTR_ERR(acl);
338         rc = posix_acl_chmod(&acl, GFP_KERNEL, inode->i_mode);
339         if (rc)
340                 return rc;
341         rc = jffs2_set_acl(inode, ACL_TYPE_ACCESS, acl);
342         posix_acl_release(acl);
343         return rc;
344 }
345
346 static size_t jffs2_acl_access_listxattr(struct dentry *dentry, char *list,
347                 size_t list_size, const char *name, size_t name_len, int type)
348 {
349         const int retlen = sizeof(POSIX_ACL_XATTR_ACCESS);
350
351         if (list && retlen <= list_size)
352                 strcpy(list, POSIX_ACL_XATTR_ACCESS);
353         return retlen;
354 }
355
356 static size_t jffs2_acl_default_listxattr(struct dentry *dentry, char *list,
357                 size_t list_size, const char *name, size_t name_len, int type)
358 {
359         const int retlen = sizeof(POSIX_ACL_XATTR_DEFAULT);
360
361         if (list && retlen <= list_size)
362                 strcpy(list, POSIX_ACL_XATTR_DEFAULT);
363         return retlen;
364 }
365
366 static int jffs2_acl_getxattr(struct dentry *dentry, const char *name,
367                 void *buffer, size_t size, int type)
368 {
369         struct posix_acl *acl;
370         int rc;
371
372         if (name[0] != '\0')
373                 return -EINVAL;
374
375         acl = jffs2_get_acl(dentry->d_inode, type);
376         if (IS_ERR(acl))
377                 return PTR_ERR(acl);
378         if (!acl)
379                 return -ENODATA;
380         rc = posix_acl_to_xattr(&init_user_ns, acl, buffer, size);
381         posix_acl_release(acl);
382
383         return rc;
384 }
385
386 static int jffs2_acl_setxattr(struct dentry *dentry, const char *name,
387                 const void *value, size_t size, int flags, int type)
388 {
389         struct posix_acl *acl;
390         int rc;
391
392         if (name[0] != '\0')
393                 return -EINVAL;
394         if (!inode_owner_or_capable(dentry->d_inode))
395                 return -EPERM;
396
397         if (value) {
398                 acl = posix_acl_from_xattr(&init_user_ns, value, size);
399                 if (IS_ERR(acl))
400                         return PTR_ERR(acl);
401                 if (acl) {
402                         rc = posix_acl_valid(acl);
403                         if (rc)
404                                 goto out;
405                 }
406         } else {
407                 acl = NULL;
408         }
409         rc = jffs2_set_acl(dentry->d_inode, type, acl);
410  out:
411         posix_acl_release(acl);
412         return rc;
413 }
414
415 const struct xattr_handler jffs2_acl_access_xattr_handler = {
416         .prefix = POSIX_ACL_XATTR_ACCESS,
417         .flags  = ACL_TYPE_DEFAULT,
418         .list   = jffs2_acl_access_listxattr,
419         .get    = jffs2_acl_getxattr,
420         .set    = jffs2_acl_setxattr,
421 };
422
423 const struct xattr_handler jffs2_acl_default_xattr_handler = {
424         .prefix = POSIX_ACL_XATTR_DEFAULT,
425         .flags  = ACL_TYPE_DEFAULT,
426         .list   = jffs2_acl_default_listxattr,
427         .get    = jffs2_acl_getxattr,
428         .set    = jffs2_acl_setxattr,
429 };