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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 <linux/init.h>
8#include <linux/sched.h>
9#include <linux/slab.h>
10#include <linux/capability.h>
11#include <linux/fs.h>
12#include "ext4_jbd2.h"
13#include "ext4.h"
14#include "xattr.h"
15#include "acl.h"
16
17/*
18 * Convert from filesystem to in-memory representation.
19 */
20static struct posix_acl *
21ext4_acl_from_disk(const void *value, size_t size)
22{
23 const char *end = (char *)value + size;
24 int n, count;
25 struct posix_acl *acl;
26
27 if (!value)
28 return NULL;
29 if (size < sizeof(ext4_acl_header))
30 return ERR_PTR(-EINVAL);
31 if (((ext4_acl_header *)value)->a_version !=
32 cpu_to_le32(EXT4_ACL_VERSION))
33 return ERR_PTR(-EINVAL);
34 value = (char *)value + sizeof(ext4_acl_header);
35 count = ext4_acl_count(size);
36 if (count < 0)
37 return ERR_PTR(-EINVAL);
38 if (count == 0)
39 return NULL;
40 acl = posix_acl_alloc(count, GFP_NOFS);
41 if (!acl)
42 return ERR_PTR(-ENOMEM);
43 for (n = 0; n < count; n++) {
44 ext4_acl_entry *entry =
45 (ext4_acl_entry *)value;
46 if ((char *)value + sizeof(ext4_acl_entry_short) > end)
47 goto fail;
48 acl->a_entries[n].e_tag = le16_to_cpu(entry->e_tag);
49 acl->a_entries[n].e_perm = le16_to_cpu(entry->e_perm);
50
51 switch (acl->a_entries[n].e_tag) {
52 case ACL_USER_OBJ:
53 case ACL_GROUP_OBJ:
54 case ACL_MASK:
55 case ACL_OTHER:
56 value = (char *)value +
57 sizeof(ext4_acl_entry_short);
58 break;
59
60 case ACL_USER:
61 value = (char *)value + sizeof(ext4_acl_entry);
62 if ((char *)value > end)
63 goto fail;
64 acl->a_entries[n].e_uid =
65 make_kuid(&init_user_ns,
66 le32_to_cpu(entry->e_id));
67 break;
68 case ACL_GROUP:
69 value = (char *)value + sizeof(ext4_acl_entry);
70 if ((char *)value > end)
71 goto fail;
72 acl->a_entries[n].e_gid =
73 make_kgid(&init_user_ns,
74 le32_to_cpu(entry->e_id));
75 break;
76
77 default:
78 goto fail;
79 }
80 }
81 if (value != end)
82 goto fail;
83 return acl;
84
85fail:
86 posix_acl_release(acl);
87 return ERR_PTR(-EINVAL);
88}
89
90/*
91 * Convert from in-memory to filesystem representation.
92 */
93static void *
94ext4_acl_to_disk(const struct posix_acl *acl, size_t *size)
95{
96 ext4_acl_header *ext_acl;
97 char *e;
98 size_t n;
99
100 *size = ext4_acl_size(acl->a_count);
101 ext_acl = kmalloc(sizeof(ext4_acl_header) + acl->a_count *
102 sizeof(ext4_acl_entry), GFP_NOFS);
103 if (!ext_acl)
104 return ERR_PTR(-ENOMEM);
105 ext_acl->a_version = cpu_to_le32(EXT4_ACL_VERSION);
106 e = (char *)ext_acl + sizeof(ext4_acl_header);
107 for (n = 0; n < acl->a_count; n++) {
108 const struct posix_acl_entry *acl_e = &acl->a_entries[n];
109 ext4_acl_entry *entry = (ext4_acl_entry *)e;
110 entry->e_tag = cpu_to_le16(acl_e->e_tag);
111 entry->e_perm = cpu_to_le16(acl_e->e_perm);
112 switch (acl_e->e_tag) {
113 case ACL_USER:
114 entry->e_id = cpu_to_le32(
115 from_kuid(&init_user_ns, acl_e->e_uid));
116 e += sizeof(ext4_acl_entry);
117 break;
118 case ACL_GROUP:
119 entry->e_id = cpu_to_le32(
120 from_kgid(&init_user_ns, acl_e->e_gid));
121 e += sizeof(ext4_acl_entry);
122 break;
123
124 case ACL_USER_OBJ:
125 case ACL_GROUP_OBJ:
126 case ACL_MASK:
127 case ACL_OTHER:
128 e += sizeof(ext4_acl_entry_short);
129 break;
130
131 default:
132 goto fail;
133 }
134 }
135 return (char *)ext_acl;
136
137fail:
138 kfree(ext_acl);
139 return ERR_PTR(-EINVAL);
140}
141
142/*
143 * Inode operation get_posix_acl().
144 *
145 * inode->i_mutex: don't care
146 */
147struct posix_acl *
148ext4_get_acl(struct inode *inode, int type)
149{
150 int name_index;
151 char *value = NULL;
152 struct posix_acl *acl;
153 int retval;
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 if (!IS_ERR(acl))
181 set_cached_acl(inode, type, acl);
182
183 return acl;
184}
185
186/*
187 * Set the access or default ACL of an inode.
188 *
189 * inode->i_mutex: down unless called from ext4_new_inode
190 */
191static int
192__ext4_set_acl(handle_t *handle, struct inode *inode, int type,
193 struct posix_acl *acl)
194{
195 int name_index;
196 void *value = NULL;
197 size_t size = 0;
198 int error;
199
200 switch (type) {
201 case ACL_TYPE_ACCESS:
202 name_index = EXT4_XATTR_INDEX_POSIX_ACL_ACCESS;
203 if (acl) {
204 error = posix_acl_equiv_mode(acl, &inode->i_mode);
205 if (error < 0)
206 return error;
207 else {
208 inode->i_ctime = ext4_current_time(inode);
209 ext4_mark_inode_dirty(handle, inode);
210 if (error == 0)
211 acl = NULL;
212 }
213 }
214 break;
215
216 case ACL_TYPE_DEFAULT:
217 name_index = EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT;
218 if (!S_ISDIR(inode->i_mode))
219 return acl ? -EACCES : 0;
220 break;
221
222 default:
223 return -EINVAL;
224 }
225 if (acl) {
226 value = ext4_acl_to_disk(acl, &size);
227 if (IS_ERR(value))
228 return (int)PTR_ERR(value);
229 }
230
231 error = ext4_xattr_set_handle(handle, inode, name_index, "",
232 value, size, 0);
233
234 kfree(value);
235 if (!error)
236 set_cached_acl(inode, type, acl);
237
238 return error;
239}
240
241int
242ext4_set_acl(struct inode *inode, struct posix_acl *acl, int type)
243{
244 handle_t *handle;
245 int error, retries = 0;
246
247retry:
248 handle = ext4_journal_start(inode, EXT4_HT_XATTR,
249 ext4_jbd2_credits_xattr(inode));
250 if (IS_ERR(handle))
251 return PTR_ERR(handle);
252
253 error = __ext4_set_acl(handle, inode, type, acl);
254 ext4_journal_stop(handle);
255 if (error == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
256 goto retry;
257 return error;
258}
259
260/*
261 * Initialize the ACLs of a new inode. Called from ext4_new_inode.
262 *
263 * dir->i_mutex: down
264 * inode->i_mutex: up (access to inode is still exclusive)
265 */
266int
267ext4_init_acl(handle_t *handle, struct inode *inode, struct inode *dir)
268{
269 struct posix_acl *default_acl, *acl;
270 int error;
271
272 error = posix_acl_create(dir, &inode->i_mode, &default_acl, &acl);
273 if (error)
274 return error;
275
276 if (default_acl) {
277 error = __ext4_set_acl(handle, inode, ACL_TYPE_DEFAULT,
278 default_acl);
279 posix_acl_release(default_acl);
280 }
281 if (acl) {
282 if (!error)
283 error = __ext4_set_acl(handle, inode, ACL_TYPE_ACCESS,
284 acl);
285 posix_acl_release(acl);
286 }
287 return error;
288}