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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 | * | |
4690148f | 21 | * xattr.c |
f41d207c PL |
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 | ||
f6db25a8 | 37 | static const 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; | |
f6db25a8 | 60 | const struct xattr_handler *handler; |
f41d207c PL |
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 | ||
5c80f5aa PL |
148 | if (prefix == name_index && name_size == name_len) |
149 | err = squashfs_read_metadata(sb, target, &start, | |
150 | &offset, name_size); | |
151 | else | |
152 | err = squashfs_read_metadata(sb, NULL, &start, | |
153 | &offset, name_size); | |
f41d207c PL |
154 | if (err < 0) |
155 | goto failed; | |
156 | ||
157 | if (prefix == name_index && name_size == name_len && | |
158 | strncmp(target, name, name_size) == 0) { | |
159 | /* found xattr */ | |
160 | if (type & SQUASHFS_XATTR_VALUE_OOL) { | |
161 | __le64 xattr; | |
162 | /* val is a reference to the real location */ | |
163 | err = squashfs_read_metadata(sb, &val, &start, | |
164 | &offset, sizeof(val)); | |
165 | if (err < 0) | |
166 | goto failed; | |
167 | err = squashfs_read_metadata(sb, &xattr, &start, | |
168 | &offset, sizeof(xattr)); | |
169 | if (err < 0) | |
170 | goto failed; | |
171 | xattr = le64_to_cpu(xattr); | |
172 | start = SQUASHFS_XATTR_BLK(xattr) + | |
173 | msblk->xattr_table; | |
174 | offset = SQUASHFS_XATTR_OFFSET(xattr); | |
175 | } | |
176 | /* read xattr value */ | |
177 | err = squashfs_read_metadata(sb, &val, &start, &offset, | |
178 | sizeof(val)); | |
179 | if (err < 0) | |
180 | goto failed; | |
181 | ||
182 | vsize = le32_to_cpu(val.vsize); | |
183 | if (buffer) { | |
184 | if (vsize > buffer_size) { | |
185 | err = -ERANGE; | |
186 | goto failed; | |
187 | } | |
188 | err = squashfs_read_metadata(sb, buffer, &start, | |
189 | &offset, vsize); | |
190 | if (err < 0) | |
191 | goto failed; | |
192 | } | |
193 | break; | |
194 | } | |
195 | ||
196 | /* no match, skip remaining xattr entry */ | |
197 | err = squashfs_read_metadata(sb, &val, &start, &offset, | |
198 | sizeof(val)); | |
199 | if (err < 0) | |
200 | goto failed; | |
201 | err = squashfs_read_metadata(sb, NULL, &start, &offset, | |
202 | le32_to_cpu(val.vsize)); | |
203 | if (err < 0) | |
204 | goto failed; | |
205 | } | |
206 | err = count ? vsize : -ENODATA; | |
207 | ||
208 | failed: | |
209 | kfree(target); | |
210 | return err; | |
211 | } | |
212 | ||
213 | ||
214 | /* | |
215 | * User namespace support | |
216 | */ | |
217 | static size_t squashfs_user_list(struct dentry *d, char *list, size_t list_size, | |
218 | const char *name, size_t name_len, int type) | |
219 | { | |
220 | if (list && XATTR_USER_PREFIX_LEN <= list_size) | |
221 | memcpy(list, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN); | |
222 | return XATTR_USER_PREFIX_LEN; | |
223 | } | |
224 | ||
225 | static int squashfs_user_get(struct dentry *d, const char *name, void *buffer, | |
226 | size_t size, int type) | |
227 | { | |
228 | if (name[0] == '\0') | |
229 | return -EINVAL; | |
230 | ||
231 | return squashfs_xattr_get(d->d_inode, SQUASHFS_XATTR_USER, name, | |
232 | buffer, size); | |
233 | } | |
234 | ||
f6db25a8 | 235 | static const struct xattr_handler squashfs_xattr_user_handler = { |
f41d207c PL |
236 | .prefix = XATTR_USER_PREFIX, |
237 | .list = squashfs_user_list, | |
238 | .get = squashfs_user_get | |
239 | }; | |
240 | ||
241 | /* | |
242 | * Trusted namespace support | |
243 | */ | |
244 | static size_t squashfs_trusted_list(struct dentry *d, char *list, | |
245 | size_t list_size, const char *name, size_t name_len, int type) | |
246 | { | |
247 | if (!capable(CAP_SYS_ADMIN)) | |
248 | return 0; | |
249 | ||
250 | if (list && XATTR_TRUSTED_PREFIX_LEN <= list_size) | |
251 | memcpy(list, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN); | |
252 | return XATTR_TRUSTED_PREFIX_LEN; | |
253 | } | |
254 | ||
255 | static int squashfs_trusted_get(struct dentry *d, const char *name, | |
256 | void *buffer, size_t size, int type) | |
257 | { | |
258 | if (name[0] == '\0') | |
259 | return -EINVAL; | |
260 | ||
261 | return squashfs_xattr_get(d->d_inode, SQUASHFS_XATTR_TRUSTED, name, | |
262 | buffer, size); | |
263 | } | |
264 | ||
f6db25a8 | 265 | static const struct xattr_handler squashfs_xattr_trusted_handler = { |
f41d207c PL |
266 | .prefix = XATTR_TRUSTED_PREFIX, |
267 | .list = squashfs_trusted_list, | |
268 | .get = squashfs_trusted_get | |
269 | }; | |
270 | ||
271 | /* | |
272 | * Security namespace support | |
273 | */ | |
274 | static size_t squashfs_security_list(struct dentry *d, char *list, | |
275 | size_t list_size, const char *name, size_t name_len, int type) | |
276 | { | |
277 | if (list && XATTR_SECURITY_PREFIX_LEN <= list_size) | |
278 | memcpy(list, XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN); | |
279 | return XATTR_SECURITY_PREFIX_LEN; | |
280 | } | |
281 | ||
282 | static int squashfs_security_get(struct dentry *d, const char *name, | |
283 | void *buffer, size_t size, int type) | |
284 | { | |
285 | if (name[0] == '\0') | |
286 | return -EINVAL; | |
287 | ||
288 | return squashfs_xattr_get(d->d_inode, SQUASHFS_XATTR_SECURITY, name, | |
289 | buffer, size); | |
290 | } | |
291 | ||
f6db25a8 | 292 | static const struct xattr_handler squashfs_xattr_security_handler = { |
f41d207c PL |
293 | .prefix = XATTR_SECURITY_PREFIX, |
294 | .list = squashfs_security_list, | |
295 | .get = squashfs_security_get | |
296 | }; | |
297 | ||
a02956e4 | 298 | static const struct xattr_handler *squashfs_xattr_handler(int type) |
f41d207c PL |
299 | { |
300 | if (type & ~(SQUASHFS_XATTR_PREFIX_MASK | SQUASHFS_XATTR_VALUE_OOL)) | |
301 | /* ignore unrecognised type */ | |
302 | return NULL; | |
303 | ||
304 | switch (type & SQUASHFS_XATTR_PREFIX_MASK) { | |
305 | case SQUASHFS_XATTR_USER: | |
306 | return &squashfs_xattr_user_handler; | |
307 | case SQUASHFS_XATTR_TRUSTED: | |
308 | return &squashfs_xattr_trusted_handler; | |
309 | case SQUASHFS_XATTR_SECURITY: | |
310 | return &squashfs_xattr_security_handler; | |
311 | default: | |
312 | /* ignore unrecognised type */ | |
313 | return NULL; | |
314 | } | |
315 | } | |
316 | ||
f6db25a8 | 317 | const struct xattr_handler *squashfs_xattr_handlers[] = { |
f41d207c PL |
318 | &squashfs_xattr_user_handler, |
319 | &squashfs_xattr_trusted_handler, | |
320 | &squashfs_xattr_security_handler, | |
321 | NULL | |
322 | }; | |
323 |