1 /*
2 * JFFS2 -- Journalling Flash File System, Version 2.
3 *
4 * Copyright © 2006 NEC Corporation
5 *
6 * Created by KaiGai Kohei <kaigai@ak.jp.nec.com>
7 *
8 * For licensing information, see the file 'LICENCE' in this directory.
9 *
10 */
11
12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
13
14 #include <linux/kernel.h>
15 #include <linux/slab.h>
16 #include <linux/fs.h>
17 #include <linux/sched.h>
18 #include <linux/time.h>
19 #include <linux/crc32.h>
20 #include <linux/jffs2.h>
21 #include <linux/xattr.h>
22 #include <linux/posix_acl_xattr.h>
23 #include <linux/mtd/mtd.h>
24 #include "nodelist.h"
25
26 static size_t jffs2_acl_size(int count)
27 {
28 if (count <= 4) {
29 return sizeof(struct jffs2_acl_header)
30 + count * sizeof(struct jffs2_acl_entry_short);
31 } else {
32 return sizeof(struct jffs2_acl_header)
33 + 4 * sizeof(struct jffs2_acl_entry_short)
34 + (count - 4) * sizeof(struct jffs2_acl_entry);
35 }
36 }
37
38 static int jffs2_acl_count(size_t size)
39 {
40 size_t s;
41
42 size -= sizeof(struct jffs2_acl_header);
43 if (size < 4 * sizeof(struct jffs2_acl_entry_short)) {
44 if (size % sizeof(struct jffs2_acl_entry_short))
45 return -1;
46 return size / sizeof(struct jffs2_acl_entry_short);
47 } else {
48 s = size - 4 * sizeof(struct jffs2_acl_entry_short);
49 if (s % sizeof(struct jffs2_acl_entry))
50 return -1;
51 return s / sizeof(struct jffs2_acl_entry) + 4;
52 }
53 }
54
55 static struct posix_acl *jffs2_acl_from_medium(void *value, size_t size)
56 {
57 void *end = value + size;
58 struct jffs2_acl_header *header = value;
59 struct jffs2_acl_entry *entry;
60 struct posix_acl *acl;
61 uint32_t ver;
62 int i, count;
63
64 if (!value)
65 return NULL;
66 if (size < sizeof(struct jffs2_acl_header))
67 return ERR_PTR(-EINVAL);
68 ver = je32_to_cpu(header->a_version);
69 if (ver != JFFS2_ACL_VERSION) {
70 JFFS2_WARNING("Invalid ACL version. (=%u)\n", ver);
71 return ERR_PTR(-EINVAL);
72 }
73
74 value += sizeof(struct jffs2_acl_header);
75 count = jffs2_acl_count(size);
76 if (count < 0)
77 return ERR_PTR(-EINVAL);
78 if (count == 0)
79 return NULL;
80
81 acl = posix_acl_alloc(count, GFP_KERNEL);
82 if (!acl)
83 return ERR_PTR(-ENOMEM);
84
85 for (i=0; i < count; i++) {
86 entry = value;
87 if (value + sizeof(struct jffs2_acl_entry_short) > end)
88 goto fail;
89 acl->a_entries[i].e_tag = je16_to_cpu(entry->e_tag);
90 acl->a_entries[i].e_perm = je16_to_cpu(entry->e_perm);
91 switch (acl->a_entries[i].e_tag) {
92 case ACL_USER_OBJ:
93 case ACL_GROUP_OBJ:
94 case ACL_MASK:
95 case ACL_OTHER:
96 value += sizeof(struct jffs2_acl_entry_short);
97 break;
98
99 case ACL_USER:
100 value += sizeof(struct jffs2_acl_entry);
101 if (value > end)
102 goto fail;
103 acl->a_entries[i].e_uid =
104 make_kuid(&init_user_ns,
105 je32_to_cpu(entry->e_id));
106 break;
107 case ACL_GROUP:
108 value += sizeof(struct jffs2_acl_entry);
109 if (value > end)
110 goto fail;
111 acl->a_entries[i].e_gid =
112 make_kgid(&init_user_ns,
113 je32_to_cpu(entry->e_id));
114 break;
115
116 default:
117 goto fail;
118 }
119 }
120 if (value != end)
121 goto fail;
122 return acl;
123 fail:
124 posix_acl_release(acl);
125 return ERR_PTR(-EINVAL);
126 }
127
128 static void *jffs2_acl_to_medium(const struct posix_acl *acl, size_t *size)
129 {
130 struct jffs2_acl_header *header;
131 struct jffs2_acl_entry *entry;
132 void *e;
133 size_t i;
134
135 *size = jffs2_acl_size(acl->a_count);
136 header = kmalloc(struct_size(header, a_entries, acl->a_count),
137 GFP_KERNEL);
138 if (!header)
139 return ERR_PTR(-ENOMEM);
140 header->a_version = cpu_to_je32(JFFS2_ACL_VERSION);
141 e = header + 1;
142 for (i=0; i < acl->a_count; i++) {
143 const struct posix_acl_entry *acl_e = &acl->a_entries[i];
144 entry = e;
145 entry->e_tag = cpu_to_je16(acl_e->e_tag);
146 entry->e_perm = cpu_to_je16(acl_e->e_perm);
147 switch(acl_e->e_tag) {
148 case ACL_USER:
149 entry->e_id = cpu_to_je32(
150 from_kuid(&init_user_ns, acl_e->e_uid));
151 e += sizeof(struct jffs2_acl_entry);
152 break;
153 case ACL_GROUP:
154 entry->e_id = cpu_to_je32(
155 from_kgid(&init_user_ns, acl_e->e_gid));
156 e += sizeof(struct jffs2_acl_entry);
157 break;
158
159 case ACL_USER_OBJ:
160 case ACL_GROUP_OBJ:
161 case ACL_MASK:
162 case ACL_OTHER:
163 e += sizeof(struct jffs2_acl_entry_short);
164 break;
165
166 default:
167 goto fail;
168 }
169 }
170 return header;
171 fail:
172 kfree(header);
173 return ERR_PTR(-EINVAL);
174 }
175
176 struct posix_acl *jffs2_get_acl(struct inode *inode, int type, bool rcu)
177 {
178 struct posix_acl *acl;
179 char *value = NULL;
180 int rc, xprefix;
181
182 if (rcu)
183 return ERR_PTR(-ECHILD);
184
185 switch (type) {
186 case ACL_TYPE_ACCESS:
187 xprefix = JFFS2_XPREFIX_ACL_ACCESS;
188 break;
189 case ACL_TYPE_DEFAULT:
190 xprefix = JFFS2_XPREFIX_ACL_DEFAULT;
191 break;
192 default:
193 BUG();
194 }
195 rc = do_jffs2_getxattr(inode, xprefix, "", NULL, 0);
196 if (rc > 0) {
197 value = kmalloc(rc, GFP_KERNEL);
198 if (!value)
199 return ERR_PTR(-ENOMEM);
200 rc = do_jffs2_getxattr(inode, xprefix, "", value, rc);
201 }
202 if (rc > 0) {
203 acl = jffs2_acl_from_medium(value, rc);
204 } else if (rc == -ENODATA || rc == -ENOSYS) {
205 acl = NULL;
206 } else {
207 acl = ERR_PTR(rc);
208 }
209 kfree(value);
210 return acl;
211 }
212
213 static int __jffs2_set_acl(struct inode *inode, int xprefix, struct posix_acl *acl)
214 {
215 char *value = NULL;
216 size_t size = 0;
217 int rc;
218
219 if (acl) {
220 value = jffs2_acl_to_medium(acl, &size);
221 if (IS_ERR(value))
222 return PTR_ERR(value);
223 }
224 rc = do_jffs2_setxattr(inode, xprefix, "", value, size, 0);
225 if (!value && rc == -ENODATA)
226 rc = 0;
227 kfree(value);
228
229 return rc;
230 }
231
232 int jffs2_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
233 struct posix_acl *acl, int type)
234 {
235 int rc, xprefix;
236 struct inode *inode = d_inode(dentry);
237
238 switch (type) {
239 case ACL_TYPE_ACCESS:
240 xprefix = JFFS2_XPREFIX_ACL_ACCESS;
241 if (acl) {
242 umode_t mode;
243
244 rc = posix_acl_update_mode(&nop_mnt_idmap, inode, &mode,
245 &acl);
246 if (rc)
247 return rc;
248 if (inode->i_mode != mode) {
249 struct iattr attr;
250
251 attr.ia_valid = ATTR_MODE | ATTR_CTIME;
252 attr.ia_mode = mode;
253 attr.ia_ctime = current_time(inode);
254 rc = jffs2_do_setattr(inode, &attr);
255 if (rc < 0)
256 return rc;
257 }
258 }
259 break;
260 case ACL_TYPE_DEFAULT:
261 xprefix = JFFS2_XPREFIX_ACL_DEFAULT;
262 if (!S_ISDIR(inode->i_mode))
263 return acl ? -EACCES : 0;
264 break;
265 default:
266 return -EINVAL;
267 }
268 rc = __jffs2_set_acl(inode, xprefix, acl);
269 if (!rc)
270 set_cached_acl(inode, type, acl);
271 return rc;
272 }
273
274 int jffs2_init_acl_pre(struct inode *dir_i, struct inode *inode, umode_t *i_mode)
275 {
276 struct posix_acl *default_acl, *acl;
277 int rc;
278
279 cache_no_acl(inode);
280
281 rc = posix_acl_create(dir_i, i_mode, &default_acl, &acl);
282 if (rc)
283 return rc;
284
285 if (default_acl) {
286 set_cached_acl(inode, ACL_TYPE_DEFAULT, default_acl);
287 posix_acl_release(default_acl);
288 }
289 if (acl) {
290 set_cached_acl(inode, ACL_TYPE_ACCESS, acl);
291 posix_acl_release(acl);
292 }
293 return 0;
294 }
295
296 int jffs2_init_acl_post(struct inode *inode)
297 {
298 int rc;
299
300 if (inode->i_default_acl) {
301 rc = __jffs2_set_acl(inode, JFFS2_XPREFIX_ACL_DEFAULT, inode->i_default_acl);
302 if (rc)
303 return rc;
304 }
305
306 if (inode->i_acl) {
307 rc = __jffs2_set_acl(inode, JFFS2_XPREFIX_ACL_ACCESS, inode->i_acl);
308 if (rc)
309 return rc;
310 }
311
312 return 0;
313 }
314
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