summaryrefslogtreecommitdiff
path: root/fs/xfs/xfs_xattr.c
blob: c325a28b89a8d4bd87f8a178300b92b7badd540a (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
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2008 Christoph Hellwig.
 * Portions Copyright (C) 2000-2008 Silicon Graphics, Inc.
 */

#include "xfs.h"
#include "xfs_shared.h"
#include "xfs_format.h"
#include "xfs_log_format.h"
#include "xfs_da_format.h"
#include "xfs_trans_resv.h"
#include "xfs_mount.h"
#include "xfs_inode.h"
#include "xfs_da_btree.h"
#include "xfs_attr.h"
#include "xfs_acl.h"
#include "xfs_log.h"
#include "xfs_xattr.h"

#include <linux/posix_acl_xattr.h>

/*
 * Get permission to use log-assisted atomic exchange of file extents.
 *
 * Callers must not be running any transactions or hold any inode locks, and
 * they must release the permission by calling xlog_drop_incompat_feat
 * when they're done.
 */
static inline int
xfs_attr_grab_log_assist(
	struct xfs_mount	*mp)
{
	int			error = 0;

	/*
	 * Protect ourselves from an idle log clearing the logged xattrs log
	 * incompat feature bit.
	 */
	xlog_use_incompat_feat(mp->m_log);

	/*
	 * If log-assisted xattrs are already enabled, the caller can use the
	 * log assisted swap functions with the log-incompat reference we got.
	 */
	if (xfs_sb_version_haslogxattrs(&mp->m_sb))
		return 0;

	/* Enable log-assisted xattrs. */
	error = xfs_add_incompat_log_feature(mp,
			XFS_SB_FEAT_INCOMPAT_LOG_XATTRS);
	if (error)
		goto drop_incompat;

	xfs_warn_mount(mp, XFS_OPSTATE_WARNED_LARP,
 "EXPERIMENTAL logged extended attributes feature in use. Use at your own risk!");

	return 0;
drop_incompat:
	xlog_drop_incompat_feat(mp->m_log);
	return error;
}

static inline void
xfs_attr_rele_log_assist(
	struct xfs_mount	*mp)
{
	xlog_drop_incompat_feat(mp->m_log);
}

static inline bool
xfs_attr_want_log_assist(
	struct xfs_mount	*mp)
{
#ifdef DEBUG
	/* Logged xattrs require a V5 super for log_incompat */
	return xfs_has_crc(mp) && xfs_globals.larp;
#else
	return false;
#endif
}

/*
 * Set or remove an xattr, having grabbed the appropriate logging resources
 * prior to calling libxfs.
 */
int
xfs_attr_change(
	struct xfs_da_args	*args)
{
	struct xfs_mount	*mp = args->dp->i_mount;
	bool			use_logging = false;
	int			error;

	ASSERT(!(args->op_flags & XFS_DA_OP_LOGGED));

	if (xfs_attr_want_log_assist(mp)) {
		error = xfs_attr_grab_log_assist(mp);
		if (error)
			return error;

		args->op_flags |= XFS_DA_OP_LOGGED;
		use_logging = true;
	}

	error = xfs_attr_set(args);

	if (use_logging)
		xfs_attr_rele_log_assist(mp);
	return error;
}


static int
xfs_xattr_get(const struct xattr_handler *handler, struct dentry *unused,
		struct inode *inode, const char *name, void *value, size_t size)
{
	struct xfs_da_args	args = {
		.dp		= XFS_I(inode),
		.attr_filter	= handler->flags,
		.name		= name,
		.namelen	= strlen(name),
		.value		= value,
		.valuelen	= size,
	};
	int			error;

	error = xfs_attr_get(&args);
	if (error)
		return error;
	return args.valuelen;
}

static int
xfs_xattr_set(const struct xattr_handler *handler,
	      struct user_namespace *mnt_userns, struct dentry *unused,
	      struct inode *inode, const char *name, const void *value,
	      size_t size, int flags)
{
	struct xfs_da_args	args = {
		.dp		= XFS_I(inode),
		.attr_filter	= handler->flags,
		.attr_flags	= flags,
		.name		= name,
		.namelen	= strlen(name),
		.value		= (void *)value,
		.valuelen	= size,
	};
	int			error;

	error = xfs_attr_change(&args);
	if (!error && (handler->flags & XFS_ATTR_ROOT))
		xfs_forget_acl(inode, name);
	return error;
}

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	= XFS_ATTR_ROOT,
	.get	= xfs_xattr_get,
	.set	= xfs_xattr_set,
};

static const struct xattr_handler xfs_xattr_security_handler = {
	.prefix	= XATTR_SECURITY_PREFIX,
	.flags	= XFS_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
	&posix_acl_access_xattr_handler,
	&posix_acl_default_xattr_handler,
#endif
	NULL
};

static void
__xfs_xattr_put_listent(
	struct xfs_attr_list_context *context,
	char *prefix,
	int prefix_len,
	unsigned char *name,
	int namelen)
{
	char *offset;
	int arraytop;

	if (context->count < 0 || context->seen_enough)
		return;

	if (!context->buffer)
		goto compute_size;

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

compute_size:
	context->count += prefix_len + namelen + 1;
	return;
}

static void
xfs_xattr_put_listent(
	struct xfs_attr_list_context *context,
	int		flags,
	unsigned char	*name,
	int		namelen,
	int		valuelen)
{
	char *prefix;
	int prefix_len;

	ASSERT(context->count >= 0);

	if (flags & XFS_ATTR_ROOT) {
#ifdef CONFIG_XFS_POSIX_ACL
		if (namelen == SGI_ACL_FILE_SIZE &&
		    strncmp(name, SGI_ACL_FILE,
			    SGI_ACL_FILE_SIZE) == 0) {
			__xfs_xattr_put_listent(
					context, XATTR_SYSTEM_PREFIX,
					XATTR_SYSTEM_PREFIX_LEN,
					XATTR_POSIX_ACL_ACCESS,
					strlen(XATTR_POSIX_ACL_ACCESS));
		} else if (namelen == SGI_ACL_DEFAULT_SIZE &&
			 strncmp(name, SGI_ACL_DEFAULT,
				 SGI_ACL_DEFAULT_SIZE) == 0) {
			__xfs_xattr_put_listent(
					context, XATTR_SYSTEM_PREFIX,
					XATTR_SYSTEM_PREFIX_LEN,
					XATTR_POSIX_ACL_DEFAULT,
					strlen(XATTR_POSIX_ACL_DEFAULT));
		}
#endif

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

		prefix = XATTR_TRUSTED_PREFIX;
		prefix_len = XATTR_TRUSTED_PREFIX_LEN;
	} else if (flags & XFS_ATTR_SECURE) {
		prefix = XATTR_SECURITY_PREFIX;
		prefix_len = XATTR_SECURITY_PREFIX_LEN;
	} else {
		prefix = XATTR_USER_PREFIX;
		prefix_len = XATTR_USER_PREFIX_LEN;
	}

	__xfs_xattr_put_listent(context, prefix, prefix_len, name,
				namelen);
	return;
}

ssize_t
xfs_vn_listxattr(
	struct dentry	*dentry,
	char		*data,
	size_t		size)
{
	struct xfs_attr_list_context context;
	struct inode	*inode = d_inode(dentry);
	int		error;

	/*
	 * First read the regular on-disk attributes.
	 */
	memset(&context, 0, sizeof(context));
	context.dp = XFS_I(inode);
	context.resynch = 1;
	context.buffer = size ? data : NULL;
	context.bufsize = size;
	context.firstu = context.bufsize;
	context.put_listent = xfs_xattr_put_listent;

	error = xfs_attr_list(&context);
	if (error)
		return error;
	if (context.count < 0)
		return -ERANGE;

	return context.count;
}