summaryrefslogtreecommitdiff
path: root/fs/xfs/xfs_xattr.c
blob: 23052992c7e216df2582d9d1847d7ec5fef23635 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
/*
 * Copyright (C) 2008 Christoph Hellwig.
 * Portions Copyright (C) 2000-2008 Silicon Graphics, Inc.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it would be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write the Free Software Foundation,
 * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */

#include "xfs.h"
#include "xfs_log_format.h"
#include "xfs_trans_resv.h"
#include "xfs_sb.h"
#include "xfs_ag.h"
#include "xfs_mount.h"
#include "xfs_da_format.h"
#include "xfs_bmap_btree.h"
#include "xfs_inode.h"
#include "xfs_attr.h"
#include "xfs_attr_leaf.h"
#include "xfs_acl.h"

#include <linux/posix_acl_xattr.h>
#include <linux/xattr.h>


static int
xfs_xattr_get(struct dentry *dentry, const char *name,
		void *value, size_t size, int xflags)
{
	struct xfs_inode *ip = XFS_I(dentry->d_inode);
	int error, asize = size;

	if (strcmp(name, "") == 0)
		return -EINVAL;

	/* Convert Linux syscall to XFS internal ATTR flags */
	if (!size) {
		xflags |= ATTR_KERNOVAL;
		value = NULL;
	}

	error = -xfs_attr_get(ip, (unsigned char *)name, value, &asize, xflags);
	if (error)
		return error;
	return asize;
}

static int
xfs_xattr_set(struct dentry *dentry, const char *name, const void *value,
		size_t size, int flags, int xflags)
{
	struct xfs_inode *ip = XFS_I(dentry->d_inode);

	if (strcmp(name, "") == 0)
		return -EINVAL;

	/* Convert Linux syscall to XFS internal ATTR flags */
	if (flags & XATTR_CREATE)
		xflags |= ATTR_CREATE;
	if (flags & XATTR_REPLACE)
		xflags |= ATTR_REPLACE;

	if (!value)
		return -xfs_attr_remove(ip, (unsigned char *)name, xflags);
	return -xfs_attr_set(ip, (unsigned char *)name,
				(void *)value, size, xflags);
}

static const struct xattr_handler xfs_xattr_user_handler = {
	.prefix	= XATTR_USER_PREFIX,
	.flags	= 0, /* no flags implies user namespace */
	.get	= xfs_xattr_get,
	.set	= xfs_xattr_set,
};

static const struct xattr_handler xfs_xattr_trusted_handler = {
	.prefix	= XATTR_TRUSTED_PREFIX,
	.flags	= ATTR_ROOT,
	.get	= xfs_xattr_get,
	.set	= xfs_xattr_set,
};

static const struct xattr_handler xfs_xattr_security_handler = {
	.prefix	= XATTR_SECURITY_PREFIX,
	.flags	= ATTR_SECURE,
	.get	= xfs_xattr_get,
	.set	= xfs_xattr_set,
};

const struct xattr_handler *xfs_xattr_handlers[] = {
	&xfs_xattr_user_handler,
	&xfs_xattr_trusted_handler,
	&xfs_xattr_security_handler,
#ifdef CONFIG_XFS_POSIX_ACL
	&xfs_xattr_acl_access_handler,
	&xfs_xattr_acl_default_handler,
#endif
	NULL
};

static unsigned int xfs_xattr_prefix_len(int flags)
{
	if (flags & XFS_ATTR_SECURE)
		return sizeof("security");
	else if (flags & XFS_ATTR_ROOT)
		return sizeof("trusted");
	else
		return sizeof("user");
}

static const char *xfs_xattr_prefix(int flags)
{
	if (flags & XFS_ATTR_SECURE)
		return xfs_xattr_security_handler.prefix;
	else if (flags & XFS_ATTR_ROOT)
		return xfs_xattr_trusted_handler.prefix;
	else
		return xfs_xattr_user_handler.prefix;
}

static int
xfs_xattr_put_listent(
	struct xfs_attr_list_context *context,
	int		flags,
	unsigned char	*name,
	int		namelen,
	int		valuelen,
	unsigned char	*value)
{
	unsigned int prefix_len = xfs_xattr_prefix_len(flags);
	char *offset;
	int arraytop;

	ASSERT(context->count >= 0);

	/*
	 * Only show root namespace entries if we are actually allowed to
	 * see them.
	 */
	if ((flags & XFS_ATTR_ROOT) && !capable(CAP_SYS_ADMIN))
		return 0;

	arraytop = context->count + prefix_len + namelen + 1;
	if (arraytop > context->firstu) {
		context->count = -1;	/* insufficient space */
		return 1;
	}
	offset = (char *)context->alist + context->count;
	strncpy(offset, xfs_xattr_prefix(flags), prefix_len);
	offset += prefix_len;
	strncpy(offset, (char *)name, namelen);			/* real name */
	offset += namelen;
	*offset = '\0';
	context->count += prefix_len + namelen + 1;
	return 0;
}

static int
xfs_xattr_put_listent_sizes(
	struct xfs_attr_list_context *context,
	int		flags,
	unsigned char	*name,
	int		namelen,
	int		valuelen,
	unsigned char	*value)
{
	context->count += xfs_xattr_prefix_len(flags) + namelen + 1;
	return 0;
}

static int
list_one_attr(const char *name, const size_t len, void *data,
		size_t size, ssize_t *result)
{
	char *p = data + *result;

	*result += len;
	if (!size)
		return 0;
	if (*result > size)
		return -ERANGE;

	strcpy(p, name);
	return 0;
}

ssize_t
xfs_vn_listxattr(struct dentry *dentry, char *data, size_t size)
{
	struct xfs_attr_list_context context;
	struct attrlist_cursor_kern cursor = { 0 };
	struct inode		*inode = dentry->d_inode;
	int			error;

	/*
	 * First read the regular on-disk attributes.
	 */
	memset(&context, 0, sizeof(context));
	context.dp = XFS_I(inode);
	context.cursor = &cursor;
	context.resynch = 1;
	context.alist = data;
	context.bufsize = size;
	context.firstu = context.bufsize;

	if (size)
		context.put_listent = xfs_xattr_put_listent;
	else
		context.put_listent = xfs_xattr_put_listent_sizes;

	xfs_attr_list_int(&context);
	if (context.count < 0)
		return -ERANGE;

	/*
	 * Then add the two synthetic ACL attributes.
	 */
	if (posix_acl_access_exists(inode)) {
		error = list_one_attr(POSIX_ACL_XATTR_ACCESS,
				strlen(POSIX_ACL_XATTR_ACCESS) + 1,
				data, size, &context.count);
		if (error)
			return error;
	}

	if (posix_acl_default_exists(inode)) {
		error = list_one_attr(POSIX_ACL_XATTR_DEFAULT,
				strlen(POSIX_ACL_XATTR_DEFAULT) + 1,
				data, size, &context.count);
		if (error)
			return error;
	}

	return context.count;
}