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[net-next-2.6.git] / fs / jffs2 / acl.c
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652ecc20
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1/*
2 * JFFS2 -- Journalling Flash File System, Version 2.
aa98d7cf 3 *
c00c310e 4 * Copyright © 2006 NEC Corporation
aa98d7cf 5 *
652ecc20
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6 * Created by KaiGai Kohei <kaigai@ak.jp.nec.com>
7 *
8 * For licensing information, see the file 'LICENCE' in this directory.
9 *
10 */
c00c310e 11
aa98d7cf
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12#include <linux/kernel.h>
13#include <linux/slab.h>
14#include <linux/fs.h>
914e2637 15#include <linux/sched.h>
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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) {
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27 return sizeof(struct jffs2_acl_header)
28 + count * sizeof(struct jffs2_acl_entry_short);
aa98d7cf 29 } else {
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30 return sizeof(struct jffs2_acl_header)
31 + 4 * sizeof(struct jffs2_acl_entry_short)
32 + (count - 4) * sizeof(struct jffs2_acl_entry);
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33 }
34}
35
36static int jffs2_acl_count(size_t size)
37{
38 size_t s;
39
de1f72fa 40 size -= sizeof(struct jffs2_acl_header);
fc371a25 41 if (size < 4 * sizeof(struct jffs2_acl_entry_short)) {
de1f72fa 42 if (size % sizeof(struct jffs2_acl_entry_short))
aa98d7cf 43 return -1;
de1f72fa 44 return size / sizeof(struct jffs2_acl_entry_short);
aa98d7cf 45 } else {
fc371a25 46 s = size - 4 * sizeof(struct jffs2_acl_entry_short);
de1f72fa 47 if (s % sizeof(struct jffs2_acl_entry))
aa98d7cf 48 return -1;
de1f72fa 49 return s / sizeof(struct jffs2_acl_entry) + 4;
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50 }
51}
52
dea80134 53static struct posix_acl *jffs2_acl_from_medium(void *value, size_t size)
aa98d7cf 54{
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55 void *end = value + size;
56 struct jffs2_acl_header *header = value;
57 struct jffs2_acl_entry *entry;
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58 struct posix_acl *acl;
59 uint32_t ver;
60 int i, count;
61
62 if (!value)
63 return NULL;
de1f72fa 64 if (size < sizeof(struct jffs2_acl_header))
aa98d7cf 65 return ERR_PTR(-EINVAL);
dea80134 66 ver = je32_to_cpu(header->a_version);
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67 if (ver != JFFS2_ACL_VERSION) {
68 JFFS2_WARNING("Invalid ACL version. (=%u)\n", ver);
69 return ERR_PTR(-EINVAL);
70 }
71
dea80134 72 value += sizeof(struct jffs2_acl_header);
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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++) {
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84 entry = value;
85 if (value + sizeof(struct jffs2_acl_entry_short) > end)
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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:
dea80134 94 value += sizeof(struct jffs2_acl_entry_short);
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95 acl->a_entries[i].e_id = ACL_UNDEFINED_ID;
96 break;
97
98 case ACL_USER:
99 case ACL_GROUP:
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100 value += sizeof(struct jffs2_acl_entry);
101 if (value > end)
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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{
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120 struct jffs2_acl_header *header;
121 struct jffs2_acl_entry *entry;
122 void *e;
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123 size_t i;
124
125 *size = jffs2_acl_size(acl->a_count);
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126 header = kmalloc(sizeof(*header) + acl->a_count * sizeof(*entry), GFP_KERNEL);
127 if (!header)
aa98d7cf 128 return ERR_PTR(-ENOMEM);
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129 header->a_version = cpu_to_je32(JFFS2_ACL_VERSION);
130 e = header + 1;
aa98d7cf 131 for (i=0; i < acl->a_count; i++) {
dea80134 132 entry = e;
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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);
de1f72fa 139 e += sizeof(struct jffs2_acl_entry);
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140 break;
141
142 case ACL_USER_OBJ:
143 case ACL_GROUP_OBJ:
144 case ACL_MASK:
145 case ACL_OTHER:
de1f72fa 146 e += sizeof(struct jffs2_acl_entry_short);
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147 break;
148
149 default:
150 goto fail;
151 }
152 }
dea80134 153 return header;
aa98d7cf 154 fail:
dea80134 155 kfree(header);
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156 return ERR_PTR(-EINVAL);
157}
158
050416e9 159static struct posix_acl *jffs2_get_acl(struct inode *inode, int type)
aa98d7cf 160{
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KK
161 struct posix_acl *acl;
162 char *value = NULL;
163 int rc, xprefix;
164
073aaa1b
AV
165 acl = get_cached_acl(inode, type);
166 if (acl != ACL_NOT_CACHED)
167 return acl;
168
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KK
169 switch (type) {
170 case ACL_TYPE_ACCESS:
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171 xprefix = JFFS2_XPREFIX_ACL_ACCESS;
172 break;
173 case ACL_TYPE_DEFAULT:
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174 xprefix = JFFS2_XPREFIX_ACL_DEFAULT;
175 break;
176 default:
073aaa1b 177 BUG();
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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);
073aaa1b
AV
195 if (!IS_ERR(acl))
196 set_cached_acl(inode, type, acl);
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KK
197 return acl;
198}
199
cfc8dc6f
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200static 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
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219static int jffs2_set_acl(struct inode *inode, int type, struct posix_acl *acl)
220{
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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) {
9ed437c5
DW
235 struct iattr attr;
236
1c24d06f 237 attr.ia_valid = ATTR_MODE | ATTR_CTIME;
9ed437c5 238 attr.ia_mode = mode;
1c24d06f 239 attr.ia_ctime = CURRENT_TIME_SEC;
9ed437c5
DW
240 rc = jffs2_do_setattr(inode, &attr);
241 if (rc < 0)
242 return rc;
aa98d7cf
KK
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 }
cfc8dc6f 256 rc = __jffs2_set_acl(inode, xprefix, acl);
073aaa1b
AV
257 if (!rc)
258 set_cached_acl(inode, type, acl);
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259 return rc;
260}
261
18f4c644 262int jffs2_check_acl(struct inode *inode, int mask)
aa98d7cf
KK
263{
264 struct posix_acl *acl;
265 int rc;
266
267 acl = jffs2_get_acl(inode, ACL_TYPE_ACCESS);
268 if (IS_ERR(acl))
269 return PTR_ERR(acl);
270 if (acl) {
271 rc = posix_acl_permission(inode, acl, mask);
272 posix_acl_release(acl);
273 return rc;
274 }
275 return -EAGAIN;
276}
277
cfc8dc6f 278int jffs2_init_acl_pre(struct inode *dir_i, struct inode *inode, int *i_mode)
aa98d7cf 279{
cfc8dc6f
KK
280 struct posix_acl *acl, *clone;
281 int rc;
aa98d7cf 282
72c04902 283 cache_no_acl(inode);
cfc8dc6f
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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) {
ce3b0f8d 293 *i_mode &= ~current_umask();
cfc8dc6f
KK
294 } else {
295 if (S_ISDIR(*i_mode))
073aaa1b 296 set_cached_acl(inode, ACL_TYPE_DEFAULT, acl);
9ed437c5 297
aa98d7cf 298 clone = posix_acl_clone(acl, GFP_KERNEL);
aa98d7cf 299 if (!clone)
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300 return -ENOMEM;
301 rc = posix_acl_create_masq(clone, (mode_t *)i_mode);
36f97bc6
JL
302 if (rc < 0) {
303 posix_acl_release(clone);
cfc8dc6f 304 return rc;
36f97bc6 305 }
cfc8dc6f 306 if (rc > 0)
073aaa1b 307 set_cached_acl(inode, ACL_TYPE_ACCESS, clone);
cfc8dc6f 308
aa98d7cf
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309 posix_acl_release(clone);
310 }
cfc8dc6f
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311 return 0;
312}
313
314int jffs2_init_acl_post(struct inode *inode)
315{
cfc8dc6f
KK
316 int rc;
317
290c263b
AV
318 if (inode->i_default_acl) {
319 rc = __jffs2_set_acl(inode, JFFS2_XPREFIX_ACL_DEFAULT, inode->i_default_acl);
cfc8dc6f
KK
320 if (rc)
321 return rc;
322 }
323
290c263b
AV
324 if (inode->i_acl) {
325 rc = __jffs2_set_acl(inode, JFFS2_XPREFIX_ACL_ACCESS, inode->i_acl);
cfc8dc6f
KK
326 if (rc)
327 return rc;
328 }
329
8d6ea587 330 return 0;
aa98d7cf
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331}
332
aa98d7cf
KK
333int jffs2_acl_chmod(struct inode *inode)
334{
335 struct posix_acl *acl, *clone;
336 int rc;
337
338 if (S_ISLNK(inode->i_mode))
339 return -EOPNOTSUPP;
340 acl = jffs2_get_acl(inode, ACL_TYPE_ACCESS);
341 if (IS_ERR(acl) || !acl)
342 return PTR_ERR(acl);
343 clone = posix_acl_clone(acl, GFP_KERNEL);
344 posix_acl_release(acl);
345 if (!clone)
346 return -ENOMEM;
347 rc = posix_acl_chmod_masq(clone, inode->i_mode);
348 if (!rc)
349 rc = jffs2_set_acl(inode, ACL_TYPE_ACCESS, clone);
350 posix_acl_release(clone);
351 return rc;
352}
353
431547b3
CH
354static size_t jffs2_acl_access_listxattr(struct dentry *dentry, char *list,
355 size_t list_size, const char *name, size_t name_len, int type)
aa98d7cf
KK
356{
357 const int retlen = sizeof(POSIX_ACL_XATTR_ACCESS);
358
359 if (list && retlen <= list_size)
360 strcpy(list, POSIX_ACL_XATTR_ACCESS);
361 return retlen;
362}
363
431547b3
CH
364static size_t jffs2_acl_default_listxattr(struct dentry *dentry, char *list,
365 size_t list_size, const char *name, size_t name_len, int type)
aa98d7cf
KK
366{
367 const int retlen = sizeof(POSIX_ACL_XATTR_DEFAULT);
368
369 if (list && retlen <= list_size)
370 strcpy(list, POSIX_ACL_XATTR_DEFAULT);
371 return retlen;
372}
373
431547b3
CH
374static int jffs2_acl_getxattr(struct dentry *dentry, const char *name,
375 void *buffer, size_t size, int type)
aa98d7cf
KK
376{
377 struct posix_acl *acl;
378 int rc;
379
431547b3
CH
380 if (name[0] != '\0')
381 return -EINVAL;
382
383 acl = jffs2_get_acl(dentry->d_inode, type);
aa98d7cf
KK
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
431547b3
CH
394static int jffs2_acl_setxattr(struct dentry *dentry, const char *name,
395 const void *value, size_t size, int flags, int type)
aa98d7cf
KK
396{
397 struct posix_acl *acl;
398 int rc;
399
431547b3
CH
400 if (name[0] != '\0')
401 return -EINVAL;
402 if (!is_owner_or_cap(dentry->d_inode))
aa98d7cf
KK
403 return -EPERM;
404
405 if (value) {
406 acl = posix_acl_from_xattr(value, size);
407 if (IS_ERR(acl))
408 return PTR_ERR(acl);
409 if (acl) {
410 rc = posix_acl_valid(acl);
411 if (rc)
412 goto out;
413 }
414 } else {
415 acl = NULL;
416 }
431547b3 417 rc = jffs2_set_acl(dentry->d_inode, type, acl);
aa98d7cf
KK
418 out:
419 posix_acl_release(acl);
420 return rc;
421}
422
365f0cb9 423const struct xattr_handler jffs2_acl_access_xattr_handler = {
aa98d7cf 424 .prefix = POSIX_ACL_XATTR_ACCESS,
431547b3 425 .flags = ACL_TYPE_DEFAULT,
aa98d7cf 426 .list = jffs2_acl_access_listxattr,
431547b3
CH
427 .get = jffs2_acl_getxattr,
428 .set = jffs2_acl_setxattr,
aa98d7cf
KK
429};
430
365f0cb9 431const struct xattr_handler jffs2_acl_default_xattr_handler = {
aa98d7cf 432 .prefix = POSIX_ACL_XATTR_DEFAULT,
431547b3 433 .flags = ACL_TYPE_DEFAULT,
aa98d7cf 434 .list = jffs2_acl_default_listxattr,
431547b3
CH
435 .get = jffs2_acl_getxattr,
436 .set = jffs2_acl_setxattr,
aa98d7cf 437};