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_format.h"
21#include "xfs_log_format.h"
22#include "xfs_trans_resv.h"
23#include "xfs_sb.h"
24#include "xfs_ag.h"
25#include "xfs_mount.h"
26#include "xfs_da_format.h"
27#include "xfs_inode.h"
28#include "xfs_attr.h"
29#include "xfs_attr_leaf.h"
30#include "xfs_acl.h"
31
32#include <linux/posix_acl_xattr.h>
33#include <linux/xattr.h>
34
35
36static int
37xfs_xattr_get(struct dentry *dentry, const char *name,
38		void *value, size_t size, int xflags)
39{
40	struct xfs_inode *ip = XFS_I(dentry->d_inode);
41	int error, asize = size;
42
43	if (strcmp(name, "") == 0)
44		return -EINVAL;
45
46	/* Convert Linux syscall to XFS internal ATTR flags */
47	if (!size) {
48		xflags |= ATTR_KERNOVAL;
49		value = NULL;
50	}
51
52	error = xfs_attr_get(ip, (unsigned char *)name, value, &asize, xflags);
53	if (error)
54		return error;
55	return asize;
56}
57
58static int
59xfs_xattr_set(struct dentry *dentry, const char *name, const void *value,
60		size_t size, int flags, int xflags)
61{
62	struct xfs_inode *ip = XFS_I(dentry->d_inode);
63
64	if (strcmp(name, "") == 0)
65		return -EINVAL;
66
67	/* Convert Linux syscall to XFS internal ATTR flags */
68	if (flags & XATTR_CREATE)
69		xflags |= ATTR_CREATE;
70	if (flags & XATTR_REPLACE)
71		xflags |= ATTR_REPLACE;
72
73	if (!value)
74		return xfs_attr_remove(ip, (unsigned char *)name, xflags);
75	return xfs_attr_set(ip, (unsigned char *)name,
76				(void *)value, size, xflags);
77}
78
79static const struct xattr_handler xfs_xattr_user_handler = {
80	.prefix	= XATTR_USER_PREFIX,
81	.flags	= 0, /* no flags implies user namespace */
82	.get	= xfs_xattr_get,
83	.set	= xfs_xattr_set,
84};
85
86static const struct xattr_handler xfs_xattr_trusted_handler = {
87	.prefix	= XATTR_TRUSTED_PREFIX,
88	.flags	= ATTR_ROOT,
89	.get	= xfs_xattr_get,
90	.set	= xfs_xattr_set,
91};
92
93static const struct xattr_handler xfs_xattr_security_handler = {
94	.prefix	= XATTR_SECURITY_PREFIX,
95	.flags	= ATTR_SECURE,
96	.get	= xfs_xattr_get,
97	.set	= xfs_xattr_set,
98};
99
100const struct xattr_handler *xfs_xattr_handlers[] = {
101	&xfs_xattr_user_handler,
102	&xfs_xattr_trusted_handler,
103	&xfs_xattr_security_handler,
104#ifdef CONFIG_XFS_POSIX_ACL
105	&posix_acl_access_xattr_handler,
106	&posix_acl_default_xattr_handler,
107#endif
108	NULL
109};
110
111static unsigned int xfs_xattr_prefix_len(int flags)
112{
113	if (flags & XFS_ATTR_SECURE)
114		return sizeof("security");
115	else if (flags & XFS_ATTR_ROOT)
116		return sizeof("trusted");
117	else
118		return sizeof("user");
119}
120
121static const char *xfs_xattr_prefix(int flags)
122{
123	if (flags & XFS_ATTR_SECURE)
124		return xfs_xattr_security_handler.prefix;
125	else if (flags & XFS_ATTR_ROOT)
126		return xfs_xattr_trusted_handler.prefix;
127	else
128		return xfs_xattr_user_handler.prefix;
129}
130
131static int
132xfs_xattr_put_listent(
133	struct xfs_attr_list_context *context,
134	int		flags,
135	unsigned char	*name,
136	int		namelen,
137	int		valuelen,
138	unsigned char	*value)
139{
140	unsigned int prefix_len = xfs_xattr_prefix_len(flags);
141	char *offset;
142	int arraytop;
143
144	ASSERT(context->count >= 0);
145
146	/*
147	 * Only show root namespace entries if we are actually allowed to
148	 * see them.
149	 */
150	if ((flags & XFS_ATTR_ROOT) && !capable(CAP_SYS_ADMIN))
151		return 0;
152
153	arraytop = context->count + prefix_len + namelen + 1;
154	if (arraytop > context->firstu) {
155		context->count = -1;	/* insufficient space */
156		return 1;
157	}
158	offset = (char *)context->alist + context->count;
159	strncpy(offset, xfs_xattr_prefix(flags), prefix_len);
160	offset += prefix_len;
161	strncpy(offset, (char *)name, namelen);			/* real name */
162	offset += namelen;
163	*offset = '\0';
164	context->count += prefix_len + namelen + 1;
165	return 0;
166}
167
168static int
169xfs_xattr_put_listent_sizes(
170	struct xfs_attr_list_context *context,
171	int		flags,
172	unsigned char	*name,
173	int		namelen,
174	int		valuelen,
175	unsigned char	*value)
176{
177	context->count += xfs_xattr_prefix_len(flags) + namelen + 1;
178	return 0;
179}
180
181static int
182list_one_attr(const char *name, const size_t len, void *data,
183		size_t size, ssize_t *result)
184{
185	char *p = data + *result;
186
187	*result += len;
188	if (!size)
189		return 0;
190	if (*result > size)
191		return -ERANGE;
192
193	strcpy(p, name);
194	return 0;
195}
196
197ssize_t
198xfs_vn_listxattr(struct dentry *dentry, char *data, size_t size)
199{
200	struct xfs_attr_list_context context;
201	struct attrlist_cursor_kern cursor = { 0 };
202	struct inode		*inode = dentry->d_inode;
203	int			error;
204
205	/*
206	 * First read the regular on-disk attributes.
207	 */
208	memset(&context, 0, sizeof(context));
209	context.dp = XFS_I(inode);
210	context.cursor = &cursor;
211	context.resynch = 1;
212	context.alist = data;
213	context.bufsize = size;
214	context.firstu = context.bufsize;
215
216	if (size)
217		context.put_listent = xfs_xattr_put_listent;
218	else
219		context.put_listent = xfs_xattr_put_listent_sizes;
220
221	xfs_attr_list_int(&context);
222	if (context.count < 0)
223		return -ERANGE;
224
225	/*
226	 * Then add the two synthetic ACL attributes.
227	 */
228	if (posix_acl_access_exists(inode)) {
229		error = list_one_attr(POSIX_ACL_XATTR_ACCESS,
230				strlen(POSIX_ACL_XATTR_ACCESS) + 1,
231				data, size, &context.count);
232		if (error)
233			return error;
234	}
235
236	if (posix_acl_default_exists(inode)) {
237		error = list_one_attr(POSIX_ACL_XATTR_DEFAULT,
238				strlen(POSIX_ACL_XATTR_DEFAULT) + 1,
239				data, size, &context.count);
240		if (error)
241			return error;
242	}
243
244	return context.count;
245}
246