Loading...
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * linux/fs/ext4/acl.c
4 *
5 * Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de>
6 */
7
8#include <linux/quotaops.h>
9#include "ext4_jbd2.h"
10#include "ext4.h"
11#include "xattr.h"
12#include "acl.h"
13
14/*
15 * Convert from filesystem to in-memory representation.
16 */
17static struct posix_acl *
18ext4_acl_from_disk(const void *value, size_t size)
19{
20 const char *end = (char *)value + size;
21 int n, count;
22 struct posix_acl *acl;
23
24 if (!value)
25 return NULL;
26 if (size < sizeof(ext4_acl_header))
27 return ERR_PTR(-EINVAL);
28 if (((ext4_acl_header *)value)->a_version !=
29 cpu_to_le32(EXT4_ACL_VERSION))
30 return ERR_PTR(-EINVAL);
31 value = (char *)value + sizeof(ext4_acl_header);
32 count = ext4_acl_count(size);
33 if (count < 0)
34 return ERR_PTR(-EINVAL);
35 if (count == 0)
36 return NULL;
37 acl = posix_acl_alloc(count, GFP_NOFS);
38 if (!acl)
39 return ERR_PTR(-ENOMEM);
40 for (n = 0; n < count; n++) {
41 ext4_acl_entry *entry =
42 (ext4_acl_entry *)value;
43 if ((char *)value + sizeof(ext4_acl_entry_short) > end)
44 goto fail;
45 acl->a_entries[n].e_tag = le16_to_cpu(entry->e_tag);
46 acl->a_entries[n].e_perm = le16_to_cpu(entry->e_perm);
47
48 switch (acl->a_entries[n].e_tag) {
49 case ACL_USER_OBJ:
50 case ACL_GROUP_OBJ:
51 case ACL_MASK:
52 case ACL_OTHER:
53 value = (char *)value +
54 sizeof(ext4_acl_entry_short);
55 break;
56
57 case ACL_USER:
58 value = (char *)value + sizeof(ext4_acl_entry);
59 if ((char *)value > end)
60 goto fail;
61 acl->a_entries[n].e_uid =
62 make_kuid(&init_user_ns,
63 le32_to_cpu(entry->e_id));
64 break;
65 case ACL_GROUP:
66 value = (char *)value + sizeof(ext4_acl_entry);
67 if ((char *)value > end)
68 goto fail;
69 acl->a_entries[n].e_gid =
70 make_kgid(&init_user_ns,
71 le32_to_cpu(entry->e_id));
72 break;
73
74 default:
75 goto fail;
76 }
77 }
78 if (value != end)
79 goto fail;
80 return acl;
81
82fail:
83 posix_acl_release(acl);
84 return ERR_PTR(-EINVAL);
85}
86
87/*
88 * Convert from in-memory to filesystem representation.
89 */
90static void *
91ext4_acl_to_disk(const struct posix_acl *acl, size_t *size)
92{
93 ext4_acl_header *ext_acl;
94 char *e;
95 size_t n;
96
97 *size = ext4_acl_size(acl->a_count);
98 ext_acl = kmalloc(sizeof(ext4_acl_header) + acl->a_count *
99 sizeof(ext4_acl_entry), GFP_NOFS);
100 if (!ext_acl)
101 return ERR_PTR(-ENOMEM);
102 ext_acl->a_version = cpu_to_le32(EXT4_ACL_VERSION);
103 e = (char *)ext_acl + sizeof(ext4_acl_header);
104 for (n = 0; n < acl->a_count; n++) {
105 const struct posix_acl_entry *acl_e = &acl->a_entries[n];
106 ext4_acl_entry *entry = (ext4_acl_entry *)e;
107 entry->e_tag = cpu_to_le16(acl_e->e_tag);
108 entry->e_perm = cpu_to_le16(acl_e->e_perm);
109 switch (acl_e->e_tag) {
110 case ACL_USER:
111 entry->e_id = cpu_to_le32(
112 from_kuid(&init_user_ns, acl_e->e_uid));
113 e += sizeof(ext4_acl_entry);
114 break;
115 case ACL_GROUP:
116 entry->e_id = cpu_to_le32(
117 from_kgid(&init_user_ns, acl_e->e_gid));
118 e += sizeof(ext4_acl_entry);
119 break;
120
121 case ACL_USER_OBJ:
122 case ACL_GROUP_OBJ:
123 case ACL_MASK:
124 case ACL_OTHER:
125 e += sizeof(ext4_acl_entry_short);
126 break;
127
128 default:
129 goto fail;
130 }
131 }
132 return (char *)ext_acl;
133
134fail:
135 kfree(ext_acl);
136 return ERR_PTR(-EINVAL);
137}
138
139/*
140 * Inode operation get_posix_acl().
141 *
142 * inode->i_rwsem: don't care
143 */
144struct posix_acl *
145ext4_get_acl(struct inode *inode, int type, bool rcu)
146{
147 int name_index;
148 char *value = NULL;
149 struct posix_acl *acl;
150 int retval;
151
152 if (rcu)
153 return ERR_PTR(-ECHILD);
154
155 switch (type) {
156 case ACL_TYPE_ACCESS:
157 name_index = EXT4_XATTR_INDEX_POSIX_ACL_ACCESS;
158 break;
159 case ACL_TYPE_DEFAULT:
160 name_index = EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT;
161 break;
162 default:
163 BUG();
164 }
165 retval = ext4_xattr_get(inode, name_index, "", NULL, 0);
166 if (retval > 0) {
167 value = kmalloc(retval, GFP_NOFS);
168 if (!value)
169 return ERR_PTR(-ENOMEM);
170 retval = ext4_xattr_get(inode, name_index, "", value, retval);
171 }
172 if (retval > 0)
173 acl = ext4_acl_from_disk(value, retval);
174 else if (retval == -ENODATA || retval == -ENOSYS)
175 acl = NULL;
176 else
177 acl = ERR_PTR(retval);
178 kfree(value);
179
180 return acl;
181}
182
183/*
184 * Set the access or default ACL of an inode.
185 *
186 * inode->i_rwsem: down unless called from ext4_new_inode
187 */
188static int
189__ext4_set_acl(handle_t *handle, struct inode *inode, int type,
190 struct posix_acl *acl, int xattr_flags)
191{
192 int name_index;
193 void *value = NULL;
194 size_t size = 0;
195 int error;
196
197 switch (type) {
198 case ACL_TYPE_ACCESS:
199 name_index = EXT4_XATTR_INDEX_POSIX_ACL_ACCESS;
200 break;
201
202 case ACL_TYPE_DEFAULT:
203 name_index = EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT;
204 if (!S_ISDIR(inode->i_mode))
205 return acl ? -EACCES : 0;
206 break;
207
208 default:
209 return -EINVAL;
210 }
211 if (acl) {
212 value = ext4_acl_to_disk(acl, &size);
213 if (IS_ERR(value))
214 return (int)PTR_ERR(value);
215 }
216
217 error = ext4_xattr_set_handle(handle, inode, name_index, "",
218 value, size, xattr_flags);
219
220 kfree(value);
221 if (!error)
222 set_cached_acl(inode, type, acl);
223
224 return error;
225}
226
227int
228ext4_set_acl(struct user_namespace *mnt_userns, struct dentry *dentry,
229 struct posix_acl *acl, int type)
230{
231 handle_t *handle;
232 int error, credits, retries = 0;
233 size_t acl_size = acl ? ext4_acl_size(acl->a_count) : 0;
234 struct inode *inode = d_inode(dentry);
235 umode_t mode = inode->i_mode;
236 int update_mode = 0;
237
238 error = dquot_initialize(inode);
239 if (error)
240 return error;
241retry:
242 error = ext4_xattr_set_credits(inode, acl_size, false /* is_create */,
243 &credits);
244 if (error)
245 return error;
246
247 handle = ext4_journal_start(inode, EXT4_HT_XATTR, credits);
248 if (IS_ERR(handle))
249 return PTR_ERR(handle);
250
251 if ((type == ACL_TYPE_ACCESS) && acl) {
252 error = posix_acl_update_mode(mnt_userns, inode, &mode, &acl);
253 if (error)
254 goto out_stop;
255 if (mode != inode->i_mode)
256 update_mode = 1;
257 }
258
259 error = __ext4_set_acl(handle, inode, type, acl, 0 /* xattr_flags */);
260 if (!error && update_mode) {
261 inode->i_mode = mode;
262 inode->i_ctime = current_time(inode);
263 error = ext4_mark_inode_dirty(handle, inode);
264 }
265out_stop:
266 ext4_journal_stop(handle);
267 if (error == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
268 goto retry;
269 return error;
270}
271
272/*
273 * Initialize the ACLs of a new inode. Called from ext4_new_inode.
274 *
275 * dir->i_rwsem: down
276 * inode->i_rwsem: up (access to inode is still exclusive)
277 */
278int
279ext4_init_acl(handle_t *handle, struct inode *inode, struct inode *dir)
280{
281 struct posix_acl *default_acl, *acl;
282 int error;
283
284 error = posix_acl_create(dir, &inode->i_mode, &default_acl, &acl);
285 if (error)
286 return error;
287
288 if (default_acl) {
289 error = __ext4_set_acl(handle, inode, ACL_TYPE_DEFAULT,
290 default_acl, XATTR_CREATE);
291 posix_acl_release(default_acl);
292 } else {
293 inode->i_default_acl = NULL;
294 }
295 if (acl) {
296 if (!error)
297 error = __ext4_set_acl(handle, inode, ACL_TYPE_ACCESS,
298 acl, XATTR_CREATE);
299 posix_acl_release(acl);
300 } else {
301 inode->i_acl = NULL;
302 }
303 return error;
304}
1/*
2 * linux/fs/ext4/acl.c
3 *
4 * Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de>
5 */
6
7#include "ext4_jbd2.h"
8#include "ext4.h"
9#include "xattr.h"
10#include "acl.h"
11
12/*
13 * Convert from filesystem to in-memory representation.
14 */
15static struct posix_acl *
16ext4_acl_from_disk(const void *value, size_t size)
17{
18 const char *end = (char *)value + size;
19 int n, count;
20 struct posix_acl *acl;
21
22 if (!value)
23 return NULL;
24 if (size < sizeof(ext4_acl_header))
25 return ERR_PTR(-EINVAL);
26 if (((ext4_acl_header *)value)->a_version !=
27 cpu_to_le32(EXT4_ACL_VERSION))
28 return ERR_PTR(-EINVAL);
29 value = (char *)value + sizeof(ext4_acl_header);
30 count = ext4_acl_count(size);
31 if (count < 0)
32 return ERR_PTR(-EINVAL);
33 if (count == 0)
34 return NULL;
35 acl = posix_acl_alloc(count, GFP_NOFS);
36 if (!acl)
37 return ERR_PTR(-ENOMEM);
38 for (n = 0; n < count; n++) {
39 ext4_acl_entry *entry =
40 (ext4_acl_entry *)value;
41 if ((char *)value + sizeof(ext4_acl_entry_short) > end)
42 goto fail;
43 acl->a_entries[n].e_tag = le16_to_cpu(entry->e_tag);
44 acl->a_entries[n].e_perm = le16_to_cpu(entry->e_perm);
45
46 switch (acl->a_entries[n].e_tag) {
47 case ACL_USER_OBJ:
48 case ACL_GROUP_OBJ:
49 case ACL_MASK:
50 case ACL_OTHER:
51 value = (char *)value +
52 sizeof(ext4_acl_entry_short);
53 break;
54
55 case ACL_USER:
56 value = (char *)value + sizeof(ext4_acl_entry);
57 if ((char *)value > end)
58 goto fail;
59 acl->a_entries[n].e_uid =
60 make_kuid(&init_user_ns,
61 le32_to_cpu(entry->e_id));
62 break;
63 case ACL_GROUP:
64 value = (char *)value + sizeof(ext4_acl_entry);
65 if ((char *)value > end)
66 goto fail;
67 acl->a_entries[n].e_gid =
68 make_kgid(&init_user_ns,
69 le32_to_cpu(entry->e_id));
70 break;
71
72 default:
73 goto fail;
74 }
75 }
76 if (value != end)
77 goto fail;
78 return acl;
79
80fail:
81 posix_acl_release(acl);
82 return ERR_PTR(-EINVAL);
83}
84
85/*
86 * Convert from in-memory to filesystem representation.
87 */
88static void *
89ext4_acl_to_disk(const struct posix_acl *acl, size_t *size)
90{
91 ext4_acl_header *ext_acl;
92 char *e;
93 size_t n;
94
95 *size = ext4_acl_size(acl->a_count);
96 ext_acl = kmalloc(sizeof(ext4_acl_header) + acl->a_count *
97 sizeof(ext4_acl_entry), GFP_NOFS);
98 if (!ext_acl)
99 return ERR_PTR(-ENOMEM);
100 ext_acl->a_version = cpu_to_le32(EXT4_ACL_VERSION);
101 e = (char *)ext_acl + sizeof(ext4_acl_header);
102 for (n = 0; n < acl->a_count; n++) {
103 const struct posix_acl_entry *acl_e = &acl->a_entries[n];
104 ext4_acl_entry *entry = (ext4_acl_entry *)e;
105 entry->e_tag = cpu_to_le16(acl_e->e_tag);
106 entry->e_perm = cpu_to_le16(acl_e->e_perm);
107 switch (acl_e->e_tag) {
108 case ACL_USER:
109 entry->e_id = cpu_to_le32(
110 from_kuid(&init_user_ns, acl_e->e_uid));
111 e += sizeof(ext4_acl_entry);
112 break;
113 case ACL_GROUP:
114 entry->e_id = cpu_to_le32(
115 from_kgid(&init_user_ns, acl_e->e_gid));
116 e += sizeof(ext4_acl_entry);
117 break;
118
119 case ACL_USER_OBJ:
120 case ACL_GROUP_OBJ:
121 case ACL_MASK:
122 case ACL_OTHER:
123 e += sizeof(ext4_acl_entry_short);
124 break;
125
126 default:
127 goto fail;
128 }
129 }
130 return (char *)ext_acl;
131
132fail:
133 kfree(ext_acl);
134 return ERR_PTR(-EINVAL);
135}
136
137/*
138 * Inode operation get_posix_acl().
139 *
140 * inode->i_mutex: don't care
141 */
142struct posix_acl *
143ext4_get_acl(struct inode *inode, int type)
144{
145 int name_index;
146 char *value = NULL;
147 struct posix_acl *acl;
148 int retval;
149
150 switch (type) {
151 case ACL_TYPE_ACCESS:
152 name_index = EXT4_XATTR_INDEX_POSIX_ACL_ACCESS;
153 break;
154 case ACL_TYPE_DEFAULT:
155 name_index = EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT;
156 break;
157 default:
158 BUG();
159 }
160 retval = ext4_xattr_get(inode, name_index, "", NULL, 0);
161 if (retval > 0) {
162 value = kmalloc(retval, GFP_NOFS);
163 if (!value)
164 return ERR_PTR(-ENOMEM);
165 retval = ext4_xattr_get(inode, name_index, "", value, retval);
166 }
167 if (retval > 0)
168 acl = ext4_acl_from_disk(value, retval);
169 else if (retval == -ENODATA || retval == -ENOSYS)
170 acl = NULL;
171 else
172 acl = ERR_PTR(retval);
173 kfree(value);
174
175 return acl;
176}
177
178/*
179 * Set the access or default ACL of an inode.
180 *
181 * inode->i_mutex: down unless called from ext4_new_inode
182 */
183static int
184__ext4_set_acl(handle_t *handle, struct inode *inode, int type,
185 struct posix_acl *acl)
186{
187 int name_index;
188 void *value = NULL;
189 size_t size = 0;
190 int error;
191
192 switch (type) {
193 case ACL_TYPE_ACCESS:
194 name_index = EXT4_XATTR_INDEX_POSIX_ACL_ACCESS;
195 if (acl) {
196 error = posix_acl_update_mode(inode, &inode->i_mode, &acl);
197 if (error)
198 return error;
199 inode->i_ctime = current_time(inode);
200 ext4_mark_inode_dirty(handle, inode);
201 }
202 break;
203
204 case ACL_TYPE_DEFAULT:
205 name_index = EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT;
206 if (!S_ISDIR(inode->i_mode))
207 return acl ? -EACCES : 0;
208 break;
209
210 default:
211 return -EINVAL;
212 }
213 if (acl) {
214 value = ext4_acl_to_disk(acl, &size);
215 if (IS_ERR(value))
216 return (int)PTR_ERR(value);
217 }
218
219 error = ext4_xattr_set_handle(handle, inode, name_index, "",
220 value, size, 0);
221
222 kfree(value);
223 if (!error)
224 set_cached_acl(inode, type, acl);
225
226 return error;
227}
228
229int
230ext4_set_acl(struct inode *inode, struct posix_acl *acl, int type)
231{
232 handle_t *handle;
233 int error, retries = 0;
234
235retry:
236 handle = ext4_journal_start(inode, EXT4_HT_XATTR,
237 ext4_jbd2_credits_xattr(inode));
238 if (IS_ERR(handle))
239 return PTR_ERR(handle);
240
241 error = __ext4_set_acl(handle, inode, type, acl);
242 ext4_journal_stop(handle);
243 if (error == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
244 goto retry;
245 return error;
246}
247
248/*
249 * Initialize the ACLs of a new inode. Called from ext4_new_inode.
250 *
251 * dir->i_mutex: down
252 * inode->i_mutex: up (access to inode is still exclusive)
253 */
254int
255ext4_init_acl(handle_t *handle, struct inode *inode, struct inode *dir)
256{
257 struct posix_acl *default_acl, *acl;
258 int error;
259
260 error = posix_acl_create(dir, &inode->i_mode, &default_acl, &acl);
261 if (error)
262 return error;
263
264 if (default_acl) {
265 error = __ext4_set_acl(handle, inode, ACL_TYPE_DEFAULT,
266 default_acl);
267 posix_acl_release(default_acl);
268 }
269 if (acl) {
270 if (!error)
271 error = __ext4_set_acl(handle, inode, ACL_TYPE_ACCESS,
272 acl);
273 posix_acl_release(acl);
274 }
275 return error;
276}