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f41d207c PL |
1 | /* |
2 | * Squashfs - a compressed read only filesystem for Linux | |
3 | * | |
4 | * Copyright (c) 2010 | |
5 | * Phillip Lougher <phillip@lougher.demon.co.uk> | |
6 | * | |
7 | * This program is free software; you can redistribute it and/or | |
8 | * modify it under the terms of the GNU General Public License | |
9 | * as published by the Free Software Foundation; either version 2, | |
10 | * or (at your option) any later version. | |
11 | * | |
12 | * This program is distributed in the hope that it will be useful, | |
13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
15 | * GNU General Public License for more details. | |
16 | * | |
17 | * You should have received a copy of the GNU General Public License | |
18 | * along with this program; if not, write to the Free Software | |
19 | * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. | |
20 | * | |
21 | * xattr_id.c | |
22 | */ | |
23 | ||
24 | #include <linux/init.h> | |
25 | #include <linux/module.h> | |
26 | #include <linux/string.h> | |
27 | #include <linux/fs.h> | |
28 | #include <linux/vfs.h> | |
29 | #include <linux/xattr.h> | |
30 | #include <linux/slab.h> | |
31 | ||
32 | #include "squashfs_fs.h" | |
33 | #include "squashfs_fs_sb.h" | |
34 | #include "squashfs_fs_i.h" | |
35 | #include "squashfs.h" | |
36 | ||
0f87ee08 | 37 | static struct xattr_handler *squashfs_xattr_handler(int); |
f41d207c PL |
38 | |
39 | ssize_t squashfs_listxattr(struct dentry *d, char *buffer, | |
40 | size_t buffer_size) | |
41 | { | |
42 | struct inode *inode = d->d_inode; | |
43 | struct super_block *sb = inode->i_sb; | |
44 | struct squashfs_sb_info *msblk = sb->s_fs_info; | |
45 | u64 start = SQUASHFS_XATTR_BLK(squashfs_i(inode)->xattr) | |
46 | + msblk->xattr_table; | |
47 | int offset = SQUASHFS_XATTR_OFFSET(squashfs_i(inode)->xattr); | |
48 | int count = squashfs_i(inode)->xattr_count; | |
49 | size_t rest = buffer_size; | |
50 | int err; | |
51 | ||
52 | /* check that the file system has xattrs */ | |
53 | if (msblk->xattr_id_table == NULL) | |
54 | return -EOPNOTSUPP; | |
55 | ||
56 | /* loop reading each xattr name */ | |
57 | while (count--) { | |
58 | struct squashfs_xattr_entry entry; | |
59 | struct squashfs_xattr_val val; | |
60 | struct xattr_handler *handler; | |
61 | int name_size, prefix_size = 0; | |
62 | ||
63 | err = squashfs_read_metadata(sb, &entry, &start, &offset, | |
64 | sizeof(entry)); | |
65 | if (err < 0) | |
66 | goto failed; | |
67 | ||
68 | name_size = le16_to_cpu(entry.size); | |
69 | handler = squashfs_xattr_handler(le16_to_cpu(entry.type)); | |
70 | if (handler) | |
71 | prefix_size = handler->list(d, buffer, rest, NULL, | |
72 | name_size, handler->flags); | |
73 | if (prefix_size) { | |
74 | if (buffer) { | |
75 | if (prefix_size + name_size + 1 > rest) { | |
76 | err = -ERANGE; | |
77 | goto failed; | |
78 | } | |
79 | buffer += prefix_size; | |
80 | } | |
81 | err = squashfs_read_metadata(sb, buffer, &start, | |
82 | &offset, name_size); | |
83 | if (err < 0) | |
84 | goto failed; | |
85 | if (buffer) { | |
86 | buffer[name_size] = '\0'; | |
87 | buffer += name_size + 1; | |
88 | } | |
89 | rest -= prefix_size + name_size + 1; | |
90 | } else { | |
91 | /* no handler or insuffficient privileges, so skip */ | |
92 | err = squashfs_read_metadata(sb, NULL, &start, | |
93 | &offset, name_size); | |
94 | if (err < 0) | |
95 | goto failed; | |
96 | } | |
97 | ||
98 | ||
99 | /* skip remaining xattr entry */ | |
100 | err = squashfs_read_metadata(sb, &val, &start, &offset, | |
101 | sizeof(val)); | |
102 | if (err < 0) | |
103 | goto failed; | |
104 | ||
105 | err = squashfs_read_metadata(sb, NULL, &start, &offset, | |
106 | le32_to_cpu(val.vsize)); | |
107 | if (err < 0) | |
108 | goto failed; | |
109 | } | |
110 | err = buffer_size - rest; | |
111 | ||
112 | failed: | |
113 | return err; | |
114 | } | |
115 | ||
116 | ||
117 | static int squashfs_xattr_get(struct inode *inode, int name_index, | |
118 | const char *name, void *buffer, size_t buffer_size) | |
119 | { | |
120 | struct super_block *sb = inode->i_sb; | |
121 | struct squashfs_sb_info *msblk = sb->s_fs_info; | |
122 | u64 start = SQUASHFS_XATTR_BLK(squashfs_i(inode)->xattr) | |
123 | + msblk->xattr_table; | |
124 | int offset = SQUASHFS_XATTR_OFFSET(squashfs_i(inode)->xattr); | |
125 | int count = squashfs_i(inode)->xattr_count; | |
126 | int name_len = strlen(name); | |
127 | int err, vsize; | |
128 | char *target = kmalloc(name_len, GFP_KERNEL); | |
129 | ||
130 | if (target == NULL) | |
131 | return -ENOMEM; | |
132 | ||
133 | /* loop reading each xattr name */ | |
134 | for (; count; count--) { | |
135 | struct squashfs_xattr_entry entry; | |
136 | struct squashfs_xattr_val val; | |
137 | int type, prefix, name_size; | |
138 | ||
139 | err = squashfs_read_metadata(sb, &entry, &start, &offset, | |
140 | sizeof(entry)); | |
141 | if (err < 0) | |
142 | goto failed; | |
143 | ||
144 | name_size = le16_to_cpu(entry.size); | |
145 | type = le16_to_cpu(entry.type); | |
146 | prefix = type & SQUASHFS_XATTR_PREFIX_MASK; | |
147 | ||
148 | err = squashfs_read_metadata(sb, target, &start, &offset, | |
149 | name_size); | |
150 | if (err < 0) | |
151 | goto failed; | |
152 | ||
153 | if (prefix == name_index && name_size == name_len && | |
154 | strncmp(target, name, name_size) == 0) { | |
155 | /* found xattr */ | |
156 | if (type & SQUASHFS_XATTR_VALUE_OOL) { | |
157 | __le64 xattr; | |
158 | /* val is a reference to the real location */ | |
159 | err = squashfs_read_metadata(sb, &val, &start, | |
160 | &offset, sizeof(val)); | |
161 | if (err < 0) | |
162 | goto failed; | |
163 | err = squashfs_read_metadata(sb, &xattr, &start, | |
164 | &offset, sizeof(xattr)); | |
165 | if (err < 0) | |
166 | goto failed; | |
167 | xattr = le64_to_cpu(xattr); | |
168 | start = SQUASHFS_XATTR_BLK(xattr) + | |
169 | msblk->xattr_table; | |
170 | offset = SQUASHFS_XATTR_OFFSET(xattr); | |
171 | } | |
172 | /* read xattr value */ | |
173 | err = squashfs_read_metadata(sb, &val, &start, &offset, | |
174 | sizeof(val)); | |
175 | if (err < 0) | |
176 | goto failed; | |
177 | ||
178 | vsize = le32_to_cpu(val.vsize); | |
179 | if (buffer) { | |
180 | if (vsize > buffer_size) { | |
181 | err = -ERANGE; | |
182 | goto failed; | |
183 | } | |
184 | err = squashfs_read_metadata(sb, buffer, &start, | |
185 | &offset, vsize); | |
186 | if (err < 0) | |
187 | goto failed; | |
188 | } | |
189 | break; | |
190 | } | |
191 | ||
192 | /* no match, skip remaining xattr entry */ | |
193 | err = squashfs_read_metadata(sb, &val, &start, &offset, | |
194 | sizeof(val)); | |
195 | if (err < 0) | |
196 | goto failed; | |
197 | err = squashfs_read_metadata(sb, NULL, &start, &offset, | |
198 | le32_to_cpu(val.vsize)); | |
199 | if (err < 0) | |
200 | goto failed; | |
201 | } | |
202 | err = count ? vsize : -ENODATA; | |
203 | ||
204 | failed: | |
205 | kfree(target); | |
206 | return err; | |
207 | } | |
208 | ||
209 | ||
210 | /* | |
211 | * User namespace support | |
212 | */ | |
213 | static size_t squashfs_user_list(struct dentry *d, char *list, size_t list_size, | |
214 | const char *name, size_t name_len, int type) | |
215 | { | |
216 | if (list && XATTR_USER_PREFIX_LEN <= list_size) | |
217 | memcpy(list, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN); | |
218 | return XATTR_USER_PREFIX_LEN; | |
219 | } | |
220 | ||
221 | static int squashfs_user_get(struct dentry *d, const char *name, void *buffer, | |
222 | size_t size, int type) | |
223 | { | |
224 | if (name[0] == '\0') | |
225 | return -EINVAL; | |
226 | ||
227 | return squashfs_xattr_get(d->d_inode, SQUASHFS_XATTR_USER, name, | |
228 | buffer, size); | |
229 | } | |
230 | ||
0f87ee08 | 231 | static struct xattr_handler squashfs_xattr_user_handler = { |
f41d207c PL |
232 | .prefix = XATTR_USER_PREFIX, |
233 | .list = squashfs_user_list, | |
234 | .get = squashfs_user_get | |
235 | }; | |
236 | ||
237 | /* | |
238 | * Trusted namespace support | |
239 | */ | |
240 | static size_t squashfs_trusted_list(struct dentry *d, char *list, | |
241 | size_t list_size, const char *name, size_t name_len, int type) | |
242 | { | |
243 | if (!capable(CAP_SYS_ADMIN)) | |
244 | return 0; | |
245 | ||
246 | if (list && XATTR_TRUSTED_PREFIX_LEN <= list_size) | |
247 | memcpy(list, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN); | |
248 | return XATTR_TRUSTED_PREFIX_LEN; | |
249 | } | |
250 | ||
251 | static int squashfs_trusted_get(struct dentry *d, const char *name, | |
252 | void *buffer, size_t size, int type) | |
253 | { | |
254 | if (name[0] == '\0') | |
255 | return -EINVAL; | |
256 | ||
257 | return squashfs_xattr_get(d->d_inode, SQUASHFS_XATTR_TRUSTED, name, | |
258 | buffer, size); | |
259 | } | |
260 | ||
0f87ee08 | 261 | static struct xattr_handler squashfs_xattr_trusted_handler = { |
f41d207c PL |
262 | .prefix = XATTR_TRUSTED_PREFIX, |
263 | .list = squashfs_trusted_list, | |
264 | .get = squashfs_trusted_get | |
265 | }; | |
266 | ||
267 | /* | |
268 | * Security namespace support | |
269 | */ | |
270 | static size_t squashfs_security_list(struct dentry *d, char *list, | |
271 | size_t list_size, const char *name, size_t name_len, int type) | |
272 | { | |
273 | if (list && XATTR_SECURITY_PREFIX_LEN <= list_size) | |
274 | memcpy(list, XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN); | |
275 | return XATTR_SECURITY_PREFIX_LEN; | |
276 | } | |
277 | ||
278 | static int squashfs_security_get(struct dentry *d, const char *name, | |
279 | void *buffer, size_t size, int type) | |
280 | { | |
281 | if (name[0] == '\0') | |
282 | return -EINVAL; | |
283 | ||
284 | return squashfs_xattr_get(d->d_inode, SQUASHFS_XATTR_SECURITY, name, | |
285 | buffer, size); | |
286 | } | |
287 | ||
0f87ee08 | 288 | static struct xattr_handler squashfs_xattr_security_handler = { |
f41d207c PL |
289 | .prefix = XATTR_SECURITY_PREFIX, |
290 | .list = squashfs_security_list, | |
291 | .get = squashfs_security_get | |
292 | }; | |
293 | ||
294 | static inline struct xattr_handler *squashfs_xattr_handler(int type) | |
295 | { | |
296 | if (type & ~(SQUASHFS_XATTR_PREFIX_MASK | SQUASHFS_XATTR_VALUE_OOL)) | |
297 | /* ignore unrecognised type */ | |
298 | return NULL; | |
299 | ||
300 | switch (type & SQUASHFS_XATTR_PREFIX_MASK) { | |
301 | case SQUASHFS_XATTR_USER: | |
302 | return &squashfs_xattr_user_handler; | |
303 | case SQUASHFS_XATTR_TRUSTED: | |
304 | return &squashfs_xattr_trusted_handler; | |
305 | case SQUASHFS_XATTR_SECURITY: | |
306 | return &squashfs_xattr_security_handler; | |
307 | default: | |
308 | /* ignore unrecognised type */ | |
309 | return NULL; | |
310 | } | |
311 | } | |
312 | ||
313 | struct xattr_handler *squashfs_xattr_handlers[] = { | |
314 | &squashfs_xattr_user_handler, | |
315 | &squashfs_xattr_trusted_handler, | |
316 | &squashfs_xattr_security_handler, | |
317 | NULL | |
318 | }; | |
319 |