Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
1/*
2 * linux/fs/ext2/acl.c
3 *
4 * Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de>
5 */
6
7#include <linux/capability.h>
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 */
19static struct posix_acl *
20ext2_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);
56 acl->a_entries[n].e_id = ACL_UNDEFINED_ID;
57 break;
58
59 case ACL_USER:
60 case ACL_GROUP:
61 value = (char *)value + sizeof(ext2_acl_entry);
62 if ((char *)value > end)
63 goto fail;
64 acl->a_entries[n].e_id =
65 le32_to_cpu(entry->e_id);
66 break;
67
68 default:
69 goto fail;
70 }
71 }
72 if (value != end)
73 goto fail;
74 return acl;
75
76fail:
77 posix_acl_release(acl);
78 return ERR_PTR(-EINVAL);
79}
80
81/*
82 * Convert from in-memory to filesystem representation.
83 */
84static void *
85ext2_acl_to_disk(const struct posix_acl *acl, size_t *size)
86{
87 ext2_acl_header *ext_acl;
88 char *e;
89 size_t n;
90
91 *size = ext2_acl_size(acl->a_count);
92 ext_acl = kmalloc(sizeof(ext2_acl_header) + acl->a_count *
93 sizeof(ext2_acl_entry), GFP_KERNEL);
94 if (!ext_acl)
95 return ERR_PTR(-ENOMEM);
96 ext_acl->a_version = cpu_to_le32(EXT2_ACL_VERSION);
97 e = (char *)ext_acl + sizeof(ext2_acl_header);
98 for (n=0; n < acl->a_count; n++) {
99 ext2_acl_entry *entry = (ext2_acl_entry *)e;
100 entry->e_tag = cpu_to_le16(acl->a_entries[n].e_tag);
101 entry->e_perm = cpu_to_le16(acl->a_entries[n].e_perm);
102 switch(acl->a_entries[n].e_tag) {
103 case ACL_USER:
104 case ACL_GROUP:
105 entry->e_id =
106 cpu_to_le32(acl->a_entries[n].e_id);
107 e += sizeof(ext2_acl_entry);
108 break;
109
110 case ACL_USER_OBJ:
111 case ACL_GROUP_OBJ:
112 case ACL_MASK:
113 case ACL_OTHER:
114 e += sizeof(ext2_acl_entry_short);
115 break;
116
117 default:
118 goto fail;
119 }
120 }
121 return (char *)ext_acl;
122
123fail:
124 kfree(ext_acl);
125 return ERR_PTR(-EINVAL);
126}
127
128/*
129 * inode->i_mutex: don't care
130 */
131struct posix_acl *
132ext2_get_acl(struct inode *inode, int type)
133{
134 int name_index;
135 char *value = NULL;
136 struct posix_acl *acl;
137 int retval;
138
139 if (!test_opt(inode->i_sb, POSIX_ACL))
140 return NULL;
141
142 acl = get_cached_acl(inode, type);
143 if (acl != ACL_NOT_CACHED)
144 return acl;
145
146 switch (type) {
147 case ACL_TYPE_ACCESS:
148 name_index = EXT2_XATTR_INDEX_POSIX_ACL_ACCESS;
149 break;
150 case ACL_TYPE_DEFAULT:
151 name_index = EXT2_XATTR_INDEX_POSIX_ACL_DEFAULT;
152 break;
153 default:
154 BUG();
155 }
156 retval = ext2_xattr_get(inode, name_index, "", NULL, 0);
157 if (retval > 0) {
158 value = kmalloc(retval, GFP_KERNEL);
159 if (!value)
160 return ERR_PTR(-ENOMEM);
161 retval = ext2_xattr_get(inode, name_index, "", value, retval);
162 }
163 if (retval > 0)
164 acl = ext2_acl_from_disk(value, retval);
165 else if (retval == -ENODATA || retval == -ENOSYS)
166 acl = NULL;
167 else
168 acl = ERR_PTR(retval);
169 kfree(value);
170
171 if (!IS_ERR(acl))
172 set_cached_acl(inode, type, acl);
173
174 return acl;
175}
176
177/*
178 * inode->i_mutex: down
179 */
180static int
181ext2_set_acl(struct inode *inode, int type, struct posix_acl *acl)
182{
183 int name_index;
184 void *value = NULL;
185 size_t size = 0;
186 int error;
187
188 if (S_ISLNK(inode->i_mode))
189 return -EOPNOTSUPP;
190 if (!test_opt(inode->i_sb, POSIX_ACL))
191 return 0;
192
193 switch(type) {
194 case ACL_TYPE_ACCESS:
195 name_index = EXT2_XATTR_INDEX_POSIX_ACL_ACCESS;
196 if (acl) {
197 error = posix_acl_equiv_mode(acl, &inode->i_mode);
198 if (error < 0)
199 return error;
200 else {
201 inode->i_ctime = CURRENT_TIME_SEC;
202 mark_inode_dirty(inode);
203 if (error == 0)
204 acl = NULL;
205 }
206 }
207 break;
208
209 case ACL_TYPE_DEFAULT:
210 name_index = EXT2_XATTR_INDEX_POSIX_ACL_DEFAULT;
211 if (!S_ISDIR(inode->i_mode))
212 return acl ? -EACCES : 0;
213 break;
214
215 default:
216 return -EINVAL;
217 }
218 if (acl) {
219 value = ext2_acl_to_disk(acl, &size);
220 if (IS_ERR(value))
221 return (int)PTR_ERR(value);
222 }
223
224 error = ext2_xattr_set(inode, name_index, "", value, size, 0);
225
226 kfree(value);
227 if (!error)
228 set_cached_acl(inode, type, acl);
229 return error;
230}
231
232/*
233 * Initialize the ACLs of a new inode. Called from ext2_new_inode.
234 *
235 * dir->i_mutex: down
236 * inode->i_mutex: up (access to inode is still exclusive)
237 */
238int
239ext2_init_acl(struct inode *inode, struct inode *dir)
240{
241 struct posix_acl *acl = NULL;
242 int error = 0;
243
244 if (!S_ISLNK(inode->i_mode)) {
245 if (test_opt(dir->i_sb, POSIX_ACL)) {
246 acl = ext2_get_acl(dir, ACL_TYPE_DEFAULT);
247 if (IS_ERR(acl))
248 return PTR_ERR(acl);
249 }
250 if (!acl)
251 inode->i_mode &= ~current_umask();
252 }
253 if (test_opt(inode->i_sb, POSIX_ACL) && acl) {
254 if (S_ISDIR(inode->i_mode)) {
255 error = ext2_set_acl(inode, ACL_TYPE_DEFAULT, acl);
256 if (error)
257 goto cleanup;
258 }
259 error = posix_acl_create(&acl, GFP_KERNEL, &inode->i_mode);
260 if (error < 0)
261 return error;
262 if (error > 0) {
263 /* This is an extended ACL */
264 error = ext2_set_acl(inode, ACL_TYPE_ACCESS, acl);
265 }
266 }
267cleanup:
268 posix_acl_release(acl);
269 return error;
270}
271
272/*
273 * Does chmod for an inode that may have an Access Control List. The
274 * inode->i_mode field must be updated to the desired value by the caller
275 * before calling this function.
276 * Returns 0 on success, or a negative error number.
277 *
278 * We change the ACL rather than storing some ACL entries in the file
279 * mode permission bits (which would be more efficient), because that
280 * would break once additional permissions (like ACL_APPEND, ACL_DELETE
281 * for directories) are added. There are no more bits available in the
282 * file mode.
283 *
284 * inode->i_mutex: down
285 */
286int
287ext2_acl_chmod(struct inode *inode)
288{
289 struct posix_acl *acl;
290 int error;
291
292 if (!test_opt(inode->i_sb, POSIX_ACL))
293 return 0;
294 if (S_ISLNK(inode->i_mode))
295 return -EOPNOTSUPP;
296 acl = ext2_get_acl(inode, ACL_TYPE_ACCESS);
297 if (IS_ERR(acl) || !acl)
298 return PTR_ERR(acl);
299 error = posix_acl_chmod(&acl, GFP_KERNEL, inode->i_mode);
300 if (error)
301 return error;
302 error = ext2_set_acl(inode, ACL_TYPE_ACCESS, acl);
303 posix_acl_release(acl);
304 return error;
305}
306
307/*
308 * Extended attribut handlers
309 */
310static size_t
311ext2_xattr_list_acl_access(struct dentry *dentry, char *list, size_t list_size,
312 const char *name, size_t name_len, int type)
313{
314 const size_t size = sizeof(POSIX_ACL_XATTR_ACCESS);
315
316 if (!test_opt(dentry->d_sb, POSIX_ACL))
317 return 0;
318 if (list && size <= list_size)
319 memcpy(list, POSIX_ACL_XATTR_ACCESS, size);
320 return size;
321}
322
323static size_t
324ext2_xattr_list_acl_default(struct dentry *dentry, char *list, size_t list_size,
325 const char *name, size_t name_len, int type)
326{
327 const size_t size = sizeof(POSIX_ACL_XATTR_DEFAULT);
328
329 if (!test_opt(dentry->d_sb, POSIX_ACL))
330 return 0;
331 if (list && size <= list_size)
332 memcpy(list, POSIX_ACL_XATTR_DEFAULT, size);
333 return size;
334}
335
336static int
337ext2_xattr_get_acl(struct dentry *dentry, const char *name, void *buffer,
338 size_t size, int type)
339{
340 struct posix_acl *acl;
341 int error;
342
343 if (strcmp(name, "") != 0)
344 return -EINVAL;
345 if (!test_opt(dentry->d_sb, POSIX_ACL))
346 return -EOPNOTSUPP;
347
348 acl = ext2_get_acl(dentry->d_inode, type);
349 if (IS_ERR(acl))
350 return PTR_ERR(acl);
351 if (acl == NULL)
352 return -ENODATA;
353 error = posix_acl_to_xattr(acl, buffer, size);
354 posix_acl_release(acl);
355
356 return error;
357}
358
359static int
360ext2_xattr_set_acl(struct dentry *dentry, const char *name, const void *value,
361 size_t size, int flags, int type)
362{
363 struct posix_acl *acl;
364 int error;
365
366 if (strcmp(name, "") != 0)
367 return -EINVAL;
368 if (!test_opt(dentry->d_sb, POSIX_ACL))
369 return -EOPNOTSUPP;
370 if (!inode_owner_or_capable(dentry->d_inode))
371 return -EPERM;
372
373 if (value) {
374 acl = posix_acl_from_xattr(value, size);
375 if (IS_ERR(acl))
376 return PTR_ERR(acl);
377 else if (acl) {
378 error = posix_acl_valid(acl);
379 if (error)
380 goto release_and_out;
381 }
382 } else
383 acl = NULL;
384
385 error = ext2_set_acl(dentry->d_inode, type, acl);
386
387release_and_out:
388 posix_acl_release(acl);
389 return error;
390}
391
392const struct xattr_handler ext2_xattr_acl_access_handler = {
393 .prefix = POSIX_ACL_XATTR_ACCESS,
394 .flags = ACL_TYPE_ACCESS,
395 .list = ext2_xattr_list_acl_access,
396 .get = ext2_xattr_get_acl,
397 .set = ext2_xattr_set_acl,
398};
399
400const struct xattr_handler ext2_xattr_acl_default_handler = {
401 .prefix = POSIX_ACL_XATTR_DEFAULT,
402 .flags = ACL_TYPE_DEFAULT,
403 .list = ext2_xattr_list_acl_default,
404 .get = ext2_xattr_get_acl,
405 .set = ext2_xattr_set_acl,
406};