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1/*
2 * Copyright (C) 2008 Christoph Hellwig.
3 * Portions Copyright (C) 2000-2008 Silicon Graphics, Inc.
4 *
5 * This program is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU General Public License as
7 * published by the Free Software Foundation.
8 *
9 * This program is distributed in the hope that it would be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write the Free Software Foundation,
16 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
17 */
18
19#include "xfs.h"
20#include "xfs_da_btree.h"
21#include "xfs_bmap_btree.h"
22#include "xfs_inode.h"
23#include "xfs_attr.h"
24#include "xfs_attr_leaf.h"
25#include "xfs_acl.h"
26#include "xfs_vnodeops.h"
27
28#include <linux/posix_acl_xattr.h>
29#include <linux/xattr.h>
30
31
32static int
33xfs_xattr_get(struct dentry *dentry, const char *name,
34 void *value, size_t size, int xflags)
35{
36 struct xfs_inode *ip = XFS_I(dentry->d_inode);
37 int error, asize = size;
38
39 if (strcmp(name, "") == 0)
40 return -EINVAL;
41
42 /* Convert Linux syscall to XFS internal ATTR flags */
43 if (!size) {
44 xflags |= ATTR_KERNOVAL;
45 value = NULL;
46 }
47
48 error = -xfs_attr_get(ip, (unsigned char *)name, value, &asize, xflags);
49 if (error)
50 return error;
51 return asize;
52}
53
54static int
55xfs_xattr_set(struct dentry *dentry, const char *name, const void *value,
56 size_t size, int flags, int xflags)
57{
58 struct xfs_inode *ip = XFS_I(dentry->d_inode);
59
60 if (strcmp(name, "") == 0)
61 return -EINVAL;
62
63 /* Convert Linux syscall to XFS internal ATTR flags */
64 if (flags & XATTR_CREATE)
65 xflags |= ATTR_CREATE;
66 if (flags & XATTR_REPLACE)
67 xflags |= ATTR_REPLACE;
68
69 if (!value)
70 return -xfs_attr_remove(ip, (unsigned char *)name, xflags);
71 return -xfs_attr_set(ip, (unsigned char *)name,
72 (void *)value, size, xflags);
73}
74
75static const struct xattr_handler xfs_xattr_user_handler = {
76 .prefix = XATTR_USER_PREFIX,
77 .flags = 0, /* no flags implies user namespace */
78 .get = xfs_xattr_get,
79 .set = xfs_xattr_set,
80};
81
82static const struct xattr_handler xfs_xattr_trusted_handler = {
83 .prefix = XATTR_TRUSTED_PREFIX,
84 .flags = ATTR_ROOT,
85 .get = xfs_xattr_get,
86 .set = xfs_xattr_set,
87};
88
89static const struct xattr_handler xfs_xattr_security_handler = {
90 .prefix = XATTR_SECURITY_PREFIX,
91 .flags = ATTR_SECURE,
92 .get = xfs_xattr_get,
93 .set = xfs_xattr_set,
94};
95
96const struct xattr_handler *xfs_xattr_handlers[] = {
97 &xfs_xattr_user_handler,
98 &xfs_xattr_trusted_handler,
99 &xfs_xattr_security_handler,
100#ifdef CONFIG_XFS_POSIX_ACL
101 &xfs_xattr_acl_access_handler,
102 &xfs_xattr_acl_default_handler,
103#endif
104 NULL
105};
106
107static unsigned int xfs_xattr_prefix_len(int flags)
108{
109 if (flags & XFS_ATTR_SECURE)
110 return sizeof("security");
111 else if (flags & XFS_ATTR_ROOT)
112 return sizeof("trusted");
113 else
114 return sizeof("user");
115}
116
117static const char *xfs_xattr_prefix(int flags)
118{
119 if (flags & XFS_ATTR_SECURE)
120 return xfs_xattr_security_handler.prefix;
121 else if (flags & XFS_ATTR_ROOT)
122 return xfs_xattr_trusted_handler.prefix;
123 else
124 return xfs_xattr_user_handler.prefix;
125}
126
127static int
128xfs_xattr_put_listent(
129 struct xfs_attr_list_context *context,
130 int flags,
131 unsigned char *name,
132 int namelen,
133 int valuelen,
134 unsigned char *value)
135{
136 unsigned int prefix_len = xfs_xattr_prefix_len(flags);
137 char *offset;
138 int arraytop;
139
140 ASSERT(context->count >= 0);
141
142 /*
143 * Only show root namespace entries if we are actually allowed to
144 * see them.
145 */
146 if ((flags & XFS_ATTR_ROOT) && !capable(CAP_SYS_ADMIN))
147 return 0;
148
149 arraytop = context->count + prefix_len + namelen + 1;
150 if (arraytop > context->firstu) {
151 context->count = -1; /* insufficient space */
152 return 1;
153 }
154 offset = (char *)context->alist + context->count;
155 strncpy(offset, xfs_xattr_prefix(flags), prefix_len);
156 offset += prefix_len;
157 strncpy(offset, (char *)name, namelen); /* real name */
158 offset += namelen;
159 *offset = '\0';
160 context->count += prefix_len + namelen + 1;
161 return 0;
162}
163
164static int
165xfs_xattr_put_listent_sizes(
166 struct xfs_attr_list_context *context,
167 int flags,
168 unsigned char *name,
169 int namelen,
170 int valuelen,
171 unsigned char *value)
172{
173 context->count += xfs_xattr_prefix_len(flags) + namelen + 1;
174 return 0;
175}
176
177static int
178list_one_attr(const char *name, const size_t len, void *data,
179 size_t size, ssize_t *result)
180{
181 char *p = data + *result;
182
183 *result += len;
184 if (!size)
185 return 0;
186 if (*result > size)
187 return -ERANGE;
188
189 strcpy(p, name);
190 return 0;
191}
192
193ssize_t
194xfs_vn_listxattr(struct dentry *dentry, char *data, size_t size)
195{
196 struct xfs_attr_list_context context;
197 struct attrlist_cursor_kern cursor = { 0 };
198 struct inode *inode = dentry->d_inode;
199 int error;
200
201 /*
202 * First read the regular on-disk attributes.
203 */
204 memset(&context, 0, sizeof(context));
205 context.dp = XFS_I(inode);
206 context.cursor = &cursor;
207 context.resynch = 1;
208 context.alist = data;
209 context.bufsize = size;
210 context.firstu = context.bufsize;
211
212 if (size)
213 context.put_listent = xfs_xattr_put_listent;
214 else
215 context.put_listent = xfs_xattr_put_listent_sizes;
216
217 xfs_attr_list_int(&context);
218 if (context.count < 0)
219 return -ERANGE;
220
221 /*
222 * Then add the two synthetic ACL attributes.
223 */
224 if (posix_acl_access_exists(inode)) {
225 error = list_one_attr(POSIX_ACL_XATTR_ACCESS,
226 strlen(POSIX_ACL_XATTR_ACCESS) + 1,
227 data, size, &context.count);
228 if (error)
229 return error;
230 }
231
232 if (posix_acl_default_exists(inode)) {
233 error = list_one_attr(POSIX_ACL_XATTR_DEFAULT,
234 strlen(POSIX_ACL_XATTR_DEFAULT) + 1,
235 data, size, &context.count);
236 if (error)
237 return error;
238 }
239
240 return context.count;
241}