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
jffs2_acl_size(int count)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
jffs2_acl_count(size_t size)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
jffs2_acl_from_medium(void * value,size_t size)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
jffs2_acl_to_medium(const struct posix_acl * acl,size_t * size)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_flex(*header, a_entries, acl->a_count);
137 if (!header)
138 return ERR_PTR(-ENOMEM);
139 header->a_version = cpu_to_je32(JFFS2_ACL_VERSION);
140 e = header + 1;
141 for (i=0; i < acl->a_count; i++) {
142 const struct posix_acl_entry *acl_e = &acl->a_entries[i];
143 entry = e;
144 entry->e_tag = cpu_to_je16(acl_e->e_tag);
145 entry->e_perm = cpu_to_je16(acl_e->e_perm);
146 switch(acl_e->e_tag) {
147 case ACL_USER:
148 entry->e_id = cpu_to_je32(
149 from_kuid(&init_user_ns, acl_e->e_uid));
150 e += sizeof(struct jffs2_acl_entry);
151 break;
152 case ACL_GROUP:
153 entry->e_id = cpu_to_je32(
154 from_kgid(&init_user_ns, acl_e->e_gid));
155 e += sizeof(struct jffs2_acl_entry);
156 break;
157
158 case ACL_USER_OBJ:
159 case ACL_GROUP_OBJ:
160 case ACL_MASK:
161 case ACL_OTHER:
162 e += sizeof(struct jffs2_acl_entry_short);
163 break;
164
165 default:
166 goto fail;
167 }
168 }
169 return header;
170 fail:
171 kfree(header);
172 return ERR_PTR(-EINVAL);
173 }
174
jffs2_get_acl(struct inode * inode,int type,bool rcu)175 struct posix_acl *jffs2_get_acl(struct inode *inode, int type, bool rcu)
176 {
177 struct posix_acl *acl;
178 char *value = NULL;
179 int rc, xprefix;
180
181 if (rcu)
182 return ERR_PTR(-ECHILD);
183
184 switch (type) {
185 case ACL_TYPE_ACCESS:
186 xprefix = JFFS2_XPREFIX_ACL_ACCESS;
187 break;
188 case ACL_TYPE_DEFAULT:
189 xprefix = JFFS2_XPREFIX_ACL_DEFAULT;
190 break;
191 default:
192 BUG();
193 }
194 rc = do_jffs2_getxattr(inode, xprefix, "", NULL, 0);
195 if (rc > 0) {
196 value = kmalloc(rc, GFP_KERNEL);
197 if (!value)
198 return ERR_PTR(-ENOMEM);
199 rc = do_jffs2_getxattr(inode, xprefix, "", value, rc);
200 }
201 if (rc > 0) {
202 acl = jffs2_acl_from_medium(value, rc);
203 } else if (rc == -ENODATA || rc == -ENOSYS) {
204 acl = NULL;
205 } else {
206 acl = ERR_PTR(rc);
207 }
208 kfree(value);
209 return acl;
210 }
211
__jffs2_set_acl(struct inode * inode,int xprefix,struct posix_acl * acl)212 static int __jffs2_set_acl(struct inode *inode, int xprefix, struct posix_acl *acl)
213 {
214 char *value = NULL;
215 size_t size = 0;
216 int rc;
217
218 if (acl) {
219 value = jffs2_acl_to_medium(acl, &size);
220 if (IS_ERR(value))
221 return PTR_ERR(value);
222 }
223 rc = do_jffs2_setxattr(inode, xprefix, "", value, size, 0);
224 if (!value && rc == -ENODATA)
225 rc = 0;
226 kfree(value);
227
228 return rc;
229 }
230
jffs2_set_acl(struct mnt_idmap * idmap,struct dentry * dentry,struct posix_acl * acl,int type)231 int jffs2_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
232 struct posix_acl *acl, int type)
233 {
234 int rc, xprefix;
235 struct inode *inode = d_inode(dentry);
236
237 switch (type) {
238 case ACL_TYPE_ACCESS:
239 xprefix = JFFS2_XPREFIX_ACL_ACCESS;
240 if (acl) {
241 umode_t mode;
242
243 rc = posix_acl_update_mode(&nop_mnt_idmap, inode, &mode,
244 &acl);
245 if (rc)
246 return rc;
247 if (inode->i_mode != mode) {
248 struct iattr attr;
249
250 attr.ia_valid = ATTR_MODE | ATTR_CTIME;
251 attr.ia_mode = mode;
252 attr.ia_ctime = current_time(inode);
253 rc = jffs2_do_setattr(inode, &attr);
254 if (rc < 0)
255 return rc;
256 }
257 }
258 break;
259 case ACL_TYPE_DEFAULT:
260 xprefix = JFFS2_XPREFIX_ACL_DEFAULT;
261 if (!S_ISDIR(inode->i_mode))
262 return acl ? -EACCES : 0;
263 break;
264 default:
265 return -EINVAL;
266 }
267 rc = __jffs2_set_acl(inode, xprefix, acl);
268 if (!rc)
269 set_cached_acl(inode, type, acl);
270 return rc;
271 }
272
jffs2_init_acl_pre(struct inode * dir_i,struct inode * inode,umode_t * i_mode)273 int jffs2_init_acl_pre(struct inode *dir_i, struct inode *inode, umode_t *i_mode)
274 {
275 struct posix_acl *default_acl, *acl;
276 int rc;
277
278 cache_no_acl(inode);
279
280 rc = posix_acl_create(dir_i, i_mode, &default_acl, &acl);
281 if (rc)
282 return rc;
283
284 if (default_acl) {
285 set_cached_acl(inode, ACL_TYPE_DEFAULT, default_acl);
286 posix_acl_release(default_acl);
287 }
288 if (acl) {
289 set_cached_acl(inode, ACL_TYPE_ACCESS, acl);
290 posix_acl_release(acl);
291 }
292 return 0;
293 }
294
jffs2_init_acl_post(struct inode * inode)295 int jffs2_init_acl_post(struct inode *inode)
296 {
297 int rc;
298
299 if (inode->i_default_acl) {
300 rc = __jffs2_set_acl(inode, JFFS2_XPREFIX_ACL_DEFAULT, inode->i_default_acl);
301 if (rc)
302 return rc;
303 }
304
305 if (inode->i_acl) {
306 rc = __jffs2_set_acl(inode, JFFS2_XPREFIX_ACL_ACCESS, inode->i_acl);
307 if (rc)
308 return rc;
309 }
310
311 return 0;
312 }
313