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Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * linux/fs/ext2/acl.c | |
3 | * | |
4 | * Copyright (C) 2001-2003 Andreas Gruenbacher, <[email protected]> | |
5 | */ | |
6 | ||
16f7e0fe | 7 | #include <linux/capability.h> |
1da177e4 LT |
8 | #include <linux/init.h> |
9 | #include <linux/sched.h> | |
10 | #include <linux/slab.h> | |
11 | #include <linux/fs.h> | |
12 | #include "ext2.h" | |
13 | #include "xattr.h" | |
14 | #include "acl.h" | |
15 | ||
16 | /* | |
17 | * Convert from filesystem to in-memory representation. | |
18 | */ | |
19 | static struct posix_acl * | |
20 | ext2_acl_from_disk(const void *value, size_t size) | |
21 | { | |
22 | const char *end = (char *)value + size; | |
23 | int n, count; | |
24 | struct posix_acl *acl; | |
25 | ||
26 | if (!value) | |
27 | return NULL; | |
28 | if (size < sizeof(ext2_acl_header)) | |
29 | return ERR_PTR(-EINVAL); | |
30 | if (((ext2_acl_header *)value)->a_version != | |
31 | cpu_to_le32(EXT2_ACL_VERSION)) | |
32 | return ERR_PTR(-EINVAL); | |
33 | value = (char *)value + sizeof(ext2_acl_header); | |
34 | count = ext2_acl_count(size); | |
35 | if (count < 0) | |
36 | return ERR_PTR(-EINVAL); | |
37 | if (count == 0) | |
38 | return NULL; | |
39 | acl = posix_acl_alloc(count, GFP_KERNEL); | |
40 | if (!acl) | |
41 | return ERR_PTR(-ENOMEM); | |
42 | for (n=0; n < count; n++) { | |
43 | ext2_acl_entry *entry = | |
44 | (ext2_acl_entry *)value; | |
45 | if ((char *)value + sizeof(ext2_acl_entry_short) > end) | |
46 | goto fail; | |
47 | acl->a_entries[n].e_tag = le16_to_cpu(entry->e_tag); | |
48 | acl->a_entries[n].e_perm = le16_to_cpu(entry->e_perm); | |
49 | switch(acl->a_entries[n].e_tag) { | |
50 | case ACL_USER_OBJ: | |
51 | case ACL_GROUP_OBJ: | |
52 | case ACL_MASK: | |
53 | case ACL_OTHER: | |
54 | value = (char *)value + | |
55 | sizeof(ext2_acl_entry_short); | |
1da177e4 LT |
56 | break; |
57 | ||
58 | case ACL_USER: | |
af84df93 EB |
59 | value = (char *)value + sizeof(ext2_acl_entry); |
60 | if ((char *)value > end) | |
61 | goto fail; | |
62 | acl->a_entries[n].e_uid = | |
63 | make_kuid(&init_user_ns, | |
64 | le32_to_cpu(entry->e_id)); | |
65 | break; | |
1da177e4 LT |
66 | case ACL_GROUP: |
67 | value = (char *)value + sizeof(ext2_acl_entry); | |
68 | if ((char *)value > end) | |
69 | goto fail; | |
af84df93 EB |
70 | acl->a_entries[n].e_gid = |
71 | make_kgid(&init_user_ns, | |
72 | le32_to_cpu(entry->e_id)); | |
1da177e4 LT |
73 | break; |
74 | ||
75 | default: | |
76 | goto fail; | |
77 | } | |
78 | } | |
79 | if (value != end) | |
80 | goto fail; | |
81 | return acl; | |
82 | ||
83 | fail: | |
84 | posix_acl_release(acl); | |
85 | return ERR_PTR(-EINVAL); | |
86 | } | |
87 | ||
88 | /* | |
89 | * Convert from in-memory to filesystem representation. | |
90 | */ | |
91 | static void * | |
92 | ext2_acl_to_disk(const struct posix_acl *acl, size_t *size) | |
93 | { | |
94 | ext2_acl_header *ext_acl; | |
95 | char *e; | |
96 | size_t n; | |
97 | ||
98 | *size = ext2_acl_size(acl->a_count); | |
f52720ca PI |
99 | ext_acl = kmalloc(sizeof(ext2_acl_header) + acl->a_count * |
100 | sizeof(ext2_acl_entry), GFP_KERNEL); | |
1da177e4 LT |
101 | if (!ext_acl) |
102 | return ERR_PTR(-ENOMEM); | |
103 | ext_acl->a_version = cpu_to_le32(EXT2_ACL_VERSION); | |
104 | e = (char *)ext_acl + sizeof(ext2_acl_header); | |
105 | for (n=0; n < acl->a_count; n++) { | |
af84df93 | 106 | const struct posix_acl_entry *acl_e = &acl->a_entries[n]; |
1da177e4 | 107 | ext2_acl_entry *entry = (ext2_acl_entry *)e; |
af84df93 EB |
108 | entry->e_tag = cpu_to_le16(acl_e->e_tag); |
109 | entry->e_perm = cpu_to_le16(acl_e->e_perm); | |
110 | switch(acl_e->e_tag) { | |
1da177e4 | 111 | case ACL_USER: |
af84df93 EB |
112 | entry->e_id = cpu_to_le32( |
113 | from_kuid(&init_user_ns, acl_e->e_uid)); | |
114 | e += sizeof(ext2_acl_entry); | |
115 | break; | |
1da177e4 | 116 | case ACL_GROUP: |
af84df93 EB |
117 | entry->e_id = cpu_to_le32( |
118 | from_kgid(&init_user_ns, acl_e->e_gid)); | |
1da177e4 LT |
119 | e += sizeof(ext2_acl_entry); |
120 | break; | |
121 | ||
122 | case ACL_USER_OBJ: | |
123 | case ACL_GROUP_OBJ: | |
124 | case ACL_MASK: | |
125 | case ACL_OTHER: | |
126 | e += sizeof(ext2_acl_entry_short); | |
127 | break; | |
128 | ||
129 | default: | |
130 | goto fail; | |
131 | } | |
132 | } | |
133 | return (char *)ext_acl; | |
134 | ||
135 | fail: | |
136 | kfree(ext_acl); | |
137 | return ERR_PTR(-EINVAL); | |
138 | } | |
139 | ||
1da177e4 | 140 | /* |
1b1dcc1b | 141 | * inode->i_mutex: don't care |
1da177e4 | 142 | */ |
4e34e719 | 143 | struct posix_acl * |
1da177e4 LT |
144 | ext2_get_acl(struct inode *inode, int type) |
145 | { | |
1da177e4 LT |
146 | int name_index; |
147 | char *value = NULL; | |
148 | struct posix_acl *acl; | |
149 | int retval; | |
150 | ||
151 | if (!test_opt(inode->i_sb, POSIX_ACL)) | |
152 | return NULL; | |
153 | ||
073aaa1b AV |
154 | acl = get_cached_acl(inode, type); |
155 | if (acl != ACL_NOT_CACHED) | |
156 | return acl; | |
157 | ||
158 | switch (type) { | |
159 | case ACL_TYPE_ACCESS: | |
160 | name_index = EXT2_XATTR_INDEX_POSIX_ACL_ACCESS; | |
161 | break; | |
162 | case ACL_TYPE_DEFAULT: | |
163 | name_index = EXT2_XATTR_INDEX_POSIX_ACL_DEFAULT; | |
164 | break; | |
165 | default: | |
166 | BUG(); | |
1da177e4 LT |
167 | } |
168 | retval = ext2_xattr_get(inode, name_index, "", NULL, 0); | |
169 | if (retval > 0) { | |
170 | value = kmalloc(retval, GFP_KERNEL); | |
171 | if (!value) | |
172 | return ERR_PTR(-ENOMEM); | |
173 | retval = ext2_xattr_get(inode, name_index, "", value, retval); | |
174 | } | |
175 | if (retval > 0) | |
176 | acl = ext2_acl_from_disk(value, retval); | |
177 | else if (retval == -ENODATA || retval == -ENOSYS) | |
178 | acl = NULL; | |
179 | else | |
180 | acl = ERR_PTR(retval); | |
f99d49ad | 181 | kfree(value); |
1da177e4 | 182 | |
073aaa1b AV |
183 | if (!IS_ERR(acl)) |
184 | set_cached_acl(inode, type, acl); | |
1da177e4 | 185 | |
1da177e4 LT |
186 | return acl; |
187 | } | |
188 | ||
189 | /* | |
1b1dcc1b | 190 | * inode->i_mutex: down |
1da177e4 LT |
191 | */ |
192 | static int | |
193 | ext2_set_acl(struct inode *inode, int type, struct posix_acl *acl) | |
194 | { | |
1da177e4 LT |
195 | int name_index; |
196 | void *value = NULL; | |
dfa08592 | 197 | size_t size = 0; |
1da177e4 LT |
198 | int error; |
199 | ||
200 | if (S_ISLNK(inode->i_mode)) | |
201 | return -EOPNOTSUPP; | |
202 | if (!test_opt(inode->i_sb, POSIX_ACL)) | |
203 | return 0; | |
204 | ||
205 | switch(type) { | |
206 | case ACL_TYPE_ACCESS: | |
207 | name_index = EXT2_XATTR_INDEX_POSIX_ACL_ACCESS; | |
208 | if (acl) { | |
d6952123 | 209 | error = posix_acl_equiv_mode(acl, &inode->i_mode); |
1da177e4 LT |
210 | if (error < 0) |
211 | return error; | |
212 | else { | |
523825bc | 213 | inode->i_ctime = CURRENT_TIME_SEC; |
1da177e4 LT |
214 | mark_inode_dirty(inode); |
215 | if (error == 0) | |
216 | acl = NULL; | |
217 | } | |
218 | } | |
219 | break; | |
220 | ||
221 | case ACL_TYPE_DEFAULT: | |
222 | name_index = EXT2_XATTR_INDEX_POSIX_ACL_DEFAULT; | |
223 | if (!S_ISDIR(inode->i_mode)) | |
224 | return acl ? -EACCES : 0; | |
225 | break; | |
226 | ||
227 | default: | |
228 | return -EINVAL; | |
229 | } | |
230 | if (acl) { | |
231 | value = ext2_acl_to_disk(acl, &size); | |
232 | if (IS_ERR(value)) | |
233 | return (int)PTR_ERR(value); | |
234 | } | |
235 | ||
236 | error = ext2_xattr_set(inode, name_index, "", value, size, 0); | |
237 | ||
f99d49ad | 238 | kfree(value); |
073aaa1b AV |
239 | if (!error) |
240 | set_cached_acl(inode, type, acl); | |
1da177e4 LT |
241 | return error; |
242 | } | |
243 | ||
1da177e4 LT |
244 | /* |
245 | * Initialize the ACLs of a new inode. Called from ext2_new_inode. | |
246 | * | |
1b1dcc1b JS |
247 | * dir->i_mutex: down |
248 | * inode->i_mutex: up (access to inode is still exclusive) | |
1da177e4 LT |
249 | */ |
250 | int | |
251 | ext2_init_acl(struct inode *inode, struct inode *dir) | |
252 | { | |
253 | struct posix_acl *acl = NULL; | |
254 | int error = 0; | |
255 | ||
256 | if (!S_ISLNK(inode->i_mode)) { | |
257 | if (test_opt(dir->i_sb, POSIX_ACL)) { | |
258 | acl = ext2_get_acl(dir, ACL_TYPE_DEFAULT); | |
259 | if (IS_ERR(acl)) | |
260 | return PTR_ERR(acl); | |
261 | } | |
262 | if (!acl) | |
ce3b0f8d | 263 | inode->i_mode &= ~current_umask(); |
1da177e4 LT |
264 | } |
265 | if (test_opt(inode->i_sb, POSIX_ACL) && acl) { | |
1da177e4 LT |
266 | if (S_ISDIR(inode->i_mode)) { |
267 | error = ext2_set_acl(inode, ACL_TYPE_DEFAULT, acl); | |
268 | if (error) | |
269 | goto cleanup; | |
270 | } | |
d3fb6120 | 271 | error = posix_acl_create(&acl, GFP_KERNEL, &inode->i_mode); |
826cae2f AV |
272 | if (error < 0) |
273 | return error; | |
826cae2f AV |
274 | if (error > 0) { |
275 | /* This is an extended ACL */ | |
276 | error = ext2_set_acl(inode, ACL_TYPE_ACCESS, acl); | |
1da177e4 | 277 | } |
1da177e4 LT |
278 | } |
279 | cleanup: | |
280 | posix_acl_release(acl); | |
281 | return error; | |
282 | } | |
283 | ||
284 | /* | |
285 | * Does chmod for an inode that may have an Access Control List. The | |
286 | * inode->i_mode field must be updated to the desired value by the caller | |
287 | * before calling this function. | |
288 | * Returns 0 on success, or a negative error number. | |
289 | * | |
290 | * We change the ACL rather than storing some ACL entries in the file | |
291 | * mode permission bits (which would be more efficient), because that | |
292 | * would break once additional permissions (like ACL_APPEND, ACL_DELETE | |
293 | * for directories) are added. There are no more bits available in the | |
294 | * file mode. | |
295 | * | |
1b1dcc1b | 296 | * inode->i_mutex: down |
1da177e4 LT |
297 | */ |
298 | int | |
299 | ext2_acl_chmod(struct inode *inode) | |
300 | { | |
bc26ab5f | 301 | struct posix_acl *acl; |
1da177e4 LT |
302 | int error; |
303 | ||
304 | if (!test_opt(inode->i_sb, POSIX_ACL)) | |
305 | return 0; | |
306 | if (S_ISLNK(inode->i_mode)) | |
307 | return -EOPNOTSUPP; | |
308 | acl = ext2_get_acl(inode, ACL_TYPE_ACCESS); | |
309 | if (IS_ERR(acl) || !acl) | |
310 | return PTR_ERR(acl); | |
5bf3258f | 311 | error = __posix_acl_chmod(&acl, GFP_KERNEL, inode->i_mode); |
bc26ab5f AV |
312 | if (error) |
313 | return error; | |
314 | error = ext2_set_acl(inode, ACL_TYPE_ACCESS, acl); | |
1da177e4 | 315 | posix_acl_release(acl); |
1da177e4 LT |
316 | return error; |
317 | } | |
318 | ||
319 | /* | |
320 | * Extended attribut handlers | |
321 | */ | |
322 | static size_t | |
431547b3 CH |
323 | ext2_xattr_list_acl_access(struct dentry *dentry, char *list, size_t list_size, |
324 | const char *name, size_t name_len, int type) | |
1da177e4 | 325 | { |
9a59f452 | 326 | const size_t size = sizeof(POSIX_ACL_XATTR_ACCESS); |
1da177e4 | 327 | |
431547b3 | 328 | if (!test_opt(dentry->d_sb, POSIX_ACL)) |
1da177e4 LT |
329 | return 0; |
330 | if (list && size <= list_size) | |
9a59f452 | 331 | memcpy(list, POSIX_ACL_XATTR_ACCESS, size); |
1da177e4 LT |
332 | return size; |
333 | } | |
334 | ||
335 | static size_t | |
431547b3 CH |
336 | ext2_xattr_list_acl_default(struct dentry *dentry, char *list, size_t list_size, |
337 | const char *name, size_t name_len, int type) | |
1da177e4 | 338 | { |
9a59f452 | 339 | const size_t size = sizeof(POSIX_ACL_XATTR_DEFAULT); |
1da177e4 | 340 | |
431547b3 | 341 | if (!test_opt(dentry->d_sb, POSIX_ACL)) |
1da177e4 LT |
342 | return 0; |
343 | if (list && size <= list_size) | |
9a59f452 | 344 | memcpy(list, POSIX_ACL_XATTR_DEFAULT, size); |
1da177e4 LT |
345 | return size; |
346 | } | |
347 | ||
348 | static int | |
431547b3 CH |
349 | ext2_xattr_get_acl(struct dentry *dentry, const char *name, void *buffer, |
350 | size_t size, int type) | |
1da177e4 LT |
351 | { |
352 | struct posix_acl *acl; | |
353 | int error; | |
354 | ||
431547b3 CH |
355 | if (strcmp(name, "") != 0) |
356 | return -EINVAL; | |
357 | if (!test_opt(dentry->d_sb, POSIX_ACL)) | |
1da177e4 LT |
358 | return -EOPNOTSUPP; |
359 | ||
431547b3 | 360 | acl = ext2_get_acl(dentry->d_inode, type); |
1da177e4 LT |
361 | if (IS_ERR(acl)) |
362 | return PTR_ERR(acl); | |
363 | if (acl == NULL) | |
364 | return -ENODATA; | |
5f3a4a28 | 365 | error = posix_acl_to_xattr(&init_user_ns, acl, buffer, size); |
1da177e4 LT |
366 | posix_acl_release(acl); |
367 | ||
368 | return error; | |
369 | } | |
370 | ||
371 | static int | |
431547b3 CH |
372 | ext2_xattr_set_acl(struct dentry *dentry, const char *name, const void *value, |
373 | size_t size, int flags, int type) | |
1da177e4 LT |
374 | { |
375 | struct posix_acl *acl; | |
376 | int error; | |
377 | ||
431547b3 CH |
378 | if (strcmp(name, "") != 0) |
379 | return -EINVAL; | |
380 | if (!test_opt(dentry->d_sb, POSIX_ACL)) | |
1da177e4 | 381 | return -EOPNOTSUPP; |
2e149670 | 382 | if (!inode_owner_or_capable(dentry->d_inode)) |
1da177e4 LT |
383 | return -EPERM; |
384 | ||
385 | if (value) { | |
5f3a4a28 | 386 | acl = posix_acl_from_xattr(&init_user_ns, value, size); |
1da177e4 LT |
387 | if (IS_ERR(acl)) |
388 | return PTR_ERR(acl); | |
389 | else if (acl) { | |
390 | error = posix_acl_valid(acl); | |
391 | if (error) | |
392 | goto release_and_out; | |
393 | } | |
394 | } else | |
395 | acl = NULL; | |
396 | ||
431547b3 | 397 | error = ext2_set_acl(dentry->d_inode, type, acl); |
1da177e4 LT |
398 | |
399 | release_and_out: | |
400 | posix_acl_release(acl); | |
401 | return error; | |
402 | } | |
403 | ||
749c72ef | 404 | const struct xattr_handler ext2_xattr_acl_access_handler = { |
9a59f452 | 405 | .prefix = POSIX_ACL_XATTR_ACCESS, |
431547b3 | 406 | .flags = ACL_TYPE_ACCESS, |
1da177e4 | 407 | .list = ext2_xattr_list_acl_access, |
431547b3 CH |
408 | .get = ext2_xattr_get_acl, |
409 | .set = ext2_xattr_set_acl, | |
1da177e4 LT |
410 | }; |
411 | ||
749c72ef | 412 | const struct xattr_handler ext2_xattr_acl_default_handler = { |
9a59f452 | 413 | .prefix = POSIX_ACL_XATTR_DEFAULT, |
431547b3 | 414 | .flags = ACL_TYPE_DEFAULT, |
1da177e4 | 415 | .list = ext2_xattr_list_acl_default, |
431547b3 CH |
416 | .get = ext2_xattr_get_acl, |
417 | .set = ext2_xattr_set_acl, | |
1da177e4 | 418 | }; |