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Phillip Lougherf41d2072010-05-17 03:17:04 +01001/*
2 * Squashfs - a compressed read only filesystem for Linux
3 *
4 * Copyright (c) 2010
Phillip Lougherd7f2ff62011-05-26 10:39:56 +01005 * Phillip Lougher <phillip@squashfs.org.uk>
Phillip Lougherf41d2072010-05-17 03:17:04 +01006 *
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 *
Phillip Lougher46901482010-05-31 18:50:22 +010021 * xattr.c
Phillip Lougherf41d2072010-05-17 03:17:04 +010022 */
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
Phillip Lougherf6db25a2010-05-23 03:29:26 +010037static const struct xattr_handler *squashfs_xattr_handler(int);
Phillip Lougherf41d2072010-05-17 03:17:04 +010038
39ssize_t squashfs_listxattr(struct dentry *d, char *buffer,
40 size_t buffer_size)
41{
David Howells2b0143b2015-03-17 22:25:59 +000042 struct inode *inode = d_inode(d);
Phillip Lougherf41d2072010-05-17 03:17:04 +010043 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;
Phillip Lougherf6db25a2010-05-23 03:29:26 +010060 const struct xattr_handler *handler;
Andreas Gruenbacher764a5c62015-12-02 14:44:43 +010061 int name_size;
Phillip Lougherf41d2072010-05-17 03:17:04 +010062
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));
Andreas Gruenbacher764a5c62015-12-02 14:44:43 +010070 if (handler && (!handler->list || handler->list(d))) {
71 const char *prefix = handler->prefix ?: handler->name;
72 size_t prefix_size = strlen(prefix);
73
Phillip Lougherf41d2072010-05-17 03:17:04 +010074 if (buffer) {
75 if (prefix_size + name_size + 1 > rest) {
76 err = -ERANGE;
77 goto failed;
78 }
Andreas Gruenbacher764a5c62015-12-02 14:44:43 +010079 memcpy(buffer, prefix, prefix_size);
Phillip Lougherf41d2072010-05-17 03:17:04 +010080 buffer += prefix_size;
81 }
82 err = squashfs_read_metadata(sb, buffer, &start,
83 &offset, name_size);
84 if (err < 0)
85 goto failed;
86 if (buffer) {
87 buffer[name_size] = '\0';
88 buffer += name_size + 1;
89 }
90 rest -= prefix_size + name_size + 1;
91 } else {
92 /* no handler or insuffficient privileges, so skip */
93 err = squashfs_read_metadata(sb, NULL, &start,
94 &offset, name_size);
95 if (err < 0)
96 goto failed;
97 }
98
99
100 /* skip remaining xattr entry */
101 err = squashfs_read_metadata(sb, &val, &start, &offset,
102 sizeof(val));
103 if (err < 0)
104 goto failed;
105
106 err = squashfs_read_metadata(sb, NULL, &start, &offset,
107 le32_to_cpu(val.vsize));
108 if (err < 0)
109 goto failed;
110 }
111 err = buffer_size - rest;
112
113failed:
114 return err;
115}
116
117
118static int squashfs_xattr_get(struct inode *inode, int name_index,
119 const char *name, void *buffer, size_t buffer_size)
120{
121 struct super_block *sb = inode->i_sb;
122 struct squashfs_sb_info *msblk = sb->s_fs_info;
123 u64 start = SQUASHFS_XATTR_BLK(squashfs_i(inode)->xattr)
124 + msblk->xattr_table;
125 int offset = SQUASHFS_XATTR_OFFSET(squashfs_i(inode)->xattr);
126 int count = squashfs_i(inode)->xattr_count;
127 int name_len = strlen(name);
128 int err, vsize;
129 char *target = kmalloc(name_len, GFP_KERNEL);
130
131 if (target == NULL)
132 return -ENOMEM;
133
134 /* loop reading each xattr name */
135 for (; count; count--) {
136 struct squashfs_xattr_entry entry;
137 struct squashfs_xattr_val val;
138 int type, prefix, name_size;
139
140 err = squashfs_read_metadata(sb, &entry, &start, &offset,
141 sizeof(entry));
142 if (err < 0)
143 goto failed;
144
145 name_size = le16_to_cpu(entry.size);
146 type = le16_to_cpu(entry.type);
147 prefix = type & SQUASHFS_XATTR_PREFIX_MASK;
148
Phillip Lougher5c80f5a2010-05-23 08:27:42 +0100149 if (prefix == name_index && name_size == name_len)
150 err = squashfs_read_metadata(sb, target, &start,
151 &offset, name_size);
152 else
153 err = squashfs_read_metadata(sb, NULL, &start,
154 &offset, name_size);
Phillip Lougherf41d2072010-05-17 03:17:04 +0100155 if (err < 0)
156 goto failed;
157
158 if (prefix == name_index && name_size == name_len &&
159 strncmp(target, name, name_size) == 0) {
160 /* found xattr */
161 if (type & SQUASHFS_XATTR_VALUE_OOL) {
Phillip Lougher07724582010-10-24 23:13:57 +0100162 __le64 xattr_val;
163 u64 xattr;
Phillip Lougherf41d2072010-05-17 03:17:04 +0100164 /* val is a reference to the real location */
165 err = squashfs_read_metadata(sb, &val, &start,
166 &offset, sizeof(val));
167 if (err < 0)
168 goto failed;
Phillip Lougher07724582010-10-24 23:13:57 +0100169 err = squashfs_read_metadata(sb, &xattr_val,
170 &start, &offset, sizeof(xattr_val));
Phillip Lougherf41d2072010-05-17 03:17:04 +0100171 if (err < 0)
172 goto failed;
Phillip Lougher07724582010-10-24 23:13:57 +0100173 xattr = le64_to_cpu(xattr_val);
Phillip Lougherf41d2072010-05-17 03:17:04 +0100174 start = SQUASHFS_XATTR_BLK(xattr) +
175 msblk->xattr_table;
176 offset = SQUASHFS_XATTR_OFFSET(xattr);
177 }
178 /* read xattr value */
179 err = squashfs_read_metadata(sb, &val, &start, &offset,
180 sizeof(val));
181 if (err < 0)
182 goto failed;
183
184 vsize = le32_to_cpu(val.vsize);
185 if (buffer) {
186 if (vsize > buffer_size) {
187 err = -ERANGE;
188 goto failed;
189 }
190 err = squashfs_read_metadata(sb, buffer, &start,
191 &offset, vsize);
192 if (err < 0)
193 goto failed;
194 }
195 break;
196 }
197
198 /* no match, skip remaining xattr entry */
199 err = squashfs_read_metadata(sb, &val, &start, &offset,
200 sizeof(val));
201 if (err < 0)
202 goto failed;
203 err = squashfs_read_metadata(sb, NULL, &start, &offset,
204 le32_to_cpu(val.vsize));
205 if (err < 0)
206 goto failed;
207 }
208 err = count ? vsize : -ENODATA;
209
210failed:
211 kfree(target);
212 return err;
213}
214
215
Andreas Gruenbacher0ddaf722015-10-04 19:18:53 +0200216static int squashfs_xattr_handler_get(const struct xattr_handler *handler,
217 struct dentry *d, const char *name,
218 void *buffer, size_t size)
Phillip Lougherf41d2072010-05-17 03:17:04 +0100219{
Andreas Gruenbacher0ddaf722015-10-04 19:18:53 +0200220 return squashfs_xattr_get(d_inode(d), handler->flags, name,
Phillip Lougherf41d2072010-05-17 03:17:04 +0100221 buffer, size);
222}
223
Andreas Gruenbacher0ddaf722015-10-04 19:18:53 +0200224/*
225 * User namespace support
226 */
Phillip Lougherf6db25a2010-05-23 03:29:26 +0100227static const struct xattr_handler squashfs_xattr_user_handler = {
Phillip Lougherf41d2072010-05-17 03:17:04 +0100228 .prefix = XATTR_USER_PREFIX,
Andreas Gruenbacher0ddaf722015-10-04 19:18:53 +0200229 .flags = SQUASHFS_XATTR_USER,
Andreas Gruenbacher0ddaf722015-10-04 19:18:53 +0200230 .get = squashfs_xattr_handler_get
Phillip Lougherf41d2072010-05-17 03:17:04 +0100231};
232
233/*
234 * Trusted namespace support
235 */
Andreas Gruenbacher764a5c62015-12-02 14:44:43 +0100236static bool squashfs_trusted_xattr_handler_list(struct dentry *d)
Phillip Lougherf41d2072010-05-17 03:17:04 +0100237{
Andreas Gruenbacher764a5c62015-12-02 14:44:43 +0100238 return capable(CAP_SYS_ADMIN);
Phillip Lougherf41d2072010-05-17 03:17:04 +0100239}
240
Phillip Lougherf6db25a2010-05-23 03:29:26 +0100241static const struct xattr_handler squashfs_xattr_trusted_handler = {
Phillip Lougherf41d2072010-05-17 03:17:04 +0100242 .prefix = XATTR_TRUSTED_PREFIX,
Andreas Gruenbacher0ddaf722015-10-04 19:18:53 +0200243 .flags = SQUASHFS_XATTR_TRUSTED,
244 .list = squashfs_trusted_xattr_handler_list,
245 .get = squashfs_xattr_handler_get
Phillip Lougherf41d2072010-05-17 03:17:04 +0100246};
247
248/*
249 * Security namespace support
250 */
Phillip Lougherf6db25a2010-05-23 03:29:26 +0100251static const struct xattr_handler squashfs_xattr_security_handler = {
Phillip Lougherf41d2072010-05-17 03:17:04 +0100252 .prefix = XATTR_SECURITY_PREFIX,
Andreas Gruenbacher0ddaf722015-10-04 19:18:53 +0200253 .flags = SQUASHFS_XATTR_SECURITY,
Andreas Gruenbacher0ddaf722015-10-04 19:18:53 +0200254 .get = squashfs_xattr_handler_get
Phillip Lougherf41d2072010-05-17 03:17:04 +0100255};
256
Phillip Loughera02956e2010-05-31 18:32:17 +0100257static const struct xattr_handler *squashfs_xattr_handler(int type)
Phillip Lougherf41d2072010-05-17 03:17:04 +0100258{
259 if (type & ~(SQUASHFS_XATTR_PREFIX_MASK | SQUASHFS_XATTR_VALUE_OOL))
260 /* ignore unrecognised type */
261 return NULL;
262
263 switch (type & SQUASHFS_XATTR_PREFIX_MASK) {
264 case SQUASHFS_XATTR_USER:
265 return &squashfs_xattr_user_handler;
266 case SQUASHFS_XATTR_TRUSTED:
267 return &squashfs_xattr_trusted_handler;
268 case SQUASHFS_XATTR_SECURITY:
269 return &squashfs_xattr_security_handler;
270 default:
271 /* ignore unrecognised type */
272 return NULL;
273 }
274}
275
Phillip Lougherf6db25a2010-05-23 03:29:26 +0100276const struct xattr_handler *squashfs_xattr_handlers[] = {
Phillip Lougherf41d2072010-05-17 03:17:04 +0100277 &squashfs_xattr_user_handler,
278 &squashfs_xattr_trusted_handler,
279 &squashfs_xattr_security_handler,
280 NULL
281};
282