summaryrefslogtreecommitdiff
path: root/fs/gfs2/acl.c
blob: 87ee309d4c24d10e6dcac60f7d8bca17558553b2 (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
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
/*
 * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
 * Copyright (C) 2004-2006 Red Hat, Inc.  All rights reserved.
 *
 * This copyrighted material is made available to anyone wishing to use,
 * modify, copy, or redistribute it subject to the terms and conditions
 * of the GNU General Public License version 2.
 */

#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/completion.h>
#include <linux/buffer_head.h>
#include <linux/xattr.h>
#include <linux/posix_acl.h>
#include <linux/posix_acl_xattr.h>
#include <linux/gfs2_ondisk.h>

#include "gfs2.h"
#include "incore.h"
#include "acl.h"
#include "xattr.h"
#include "glock.h"
#include "inode.h"
#include "meta_io.h"
#include "trans.h"
#include "util.h"

static const char *gfs2_acl_name(int type)
{
	switch (type) {
	case ACL_TYPE_ACCESS:
		return GFS2_POSIX_ACL_ACCESS;
	case ACL_TYPE_DEFAULT:
		return GFS2_POSIX_ACL_DEFAULT;
	}
	return NULL;
}

static struct posix_acl *gfs2_acl_get(struct gfs2_inode *ip, int type)
{
	struct posix_acl *acl;
	const char *name;
	char *data;
	int len;

	if (!ip->i_eattr)
		return NULL;

	acl = get_cached_acl(&ip->i_inode, type);
	if (acl != ACL_NOT_CACHED)
		return acl;

	name = gfs2_acl_name(type);
	if (name == NULL)
		return ERR_PTR(-EINVAL);

	len = gfs2_xattr_acl_get(ip, name, &data);
	if (len < 0)
		return ERR_PTR(len);
	if (len == 0)
		return NULL;

	acl = posix_acl_from_xattr(data, len);
	kfree(data);
	return acl;
}

/**
 * gfs2_check_acl - Check an ACL to see if we're allowed to do something
 * @inode: the file we want to do something to
 * @mask: what we want to do
 *
 * Returns: errno
 */

int gfs2_check_acl(struct inode *inode, int mask)
{
	struct posix_acl *acl;
	int error;

	acl = gfs2_acl_get(GFS2_I(inode), ACL_TYPE_ACCESS);
	if (IS_ERR(acl))
		return PTR_ERR(acl);

	if (acl) {
		error = posix_acl_permission(inode, acl, mask);
		posix_acl_release(acl);
		return error;
	}

	return -EAGAIN;
}

static int gfs2_set_mode(struct inode *inode, mode_t mode)
{
	int error = 0;

	if (mode != inode->i_mode) {
		struct iattr iattr;

		iattr.ia_valid = ATTR_MODE;
		iattr.ia_mode = mode;

		error = gfs2_setattr_simple(GFS2_I(inode), &iattr);
	}

	return error;
}

static int gfs2_acl_set(struct inode *inode, int type, struct posix_acl *acl)
{
	int error;
	int len;
	char *data;
	const char *name = gfs2_acl_name(type);

	BUG_ON(name == NULL);
	len = posix_acl_to_xattr(acl, NULL, 0);
	if (len == 0)
		return 0;
	data = kmalloc(len, GFP_NOFS);
	if (data == NULL)
		return -ENOMEM;
	error = posix_acl_to_xattr(acl, data, len);
	if (error < 0)
		goto out;
	error = __gfs2_xattr_set(inode, name, data, len, 0, GFS2_EATYPE_SYS);
	if (!error)
		set_cached_acl(inode, type, acl);
out:
	kfree(data);
	return error;
}

int gfs2_acl_create(struct gfs2_inode *dip, struct inode *inode)
{
	struct gfs2_sbd *sdp = GFS2_SB(&dip->i_inode);
	struct posix_acl *acl, *clone;
	mode_t mode = inode->i_mode;
	int error = 0;

	if (!sdp->sd_args.ar_posix_acl)
		return 0;
	if (S_ISLNK(inode->i_mode))
		return 0;

	acl = gfs2_acl_get(dip, ACL_TYPE_DEFAULT);
	if (IS_ERR(acl))
		return PTR_ERR(acl);
	if (!acl) {
		mode &= ~current_umask();
		if (mode != inode->i_mode)
			error = gfs2_set_mode(inode, mode);
		return error;
	}

	if (S_ISDIR(inode->i_mode)) {
		error = gfs2_acl_set(inode, ACL_TYPE_DEFAULT, acl);
		if (error)
			goto out;
	}

	clone = posix_acl_clone(acl, GFP_NOFS);
	error = -ENOMEM;
	if (!clone)
		goto out;
	posix_acl_release(acl);
	acl = clone;

	error = posix_acl_create_masq(acl, &mode);
	if (error < 0)
		goto out;
	if (error == 0)
		goto munge;

	error = gfs2_acl_set(inode, ACL_TYPE_ACCESS, acl);
	if (error)
		goto out;
munge:
	error = gfs2_set_mode(inode, mode);
out:
	posix_acl_release(acl);
	return error;
}

int gfs2_acl_chmod(struct gfs2_inode *ip, struct iattr *attr)
{
	struct posix_acl *acl, *clone;
	char *data;
	unsigned int len;
	int error;

	acl = gfs2_acl_get(ip, ACL_TYPE_ACCESS);
	if (IS_ERR(acl))
		return PTR_ERR(acl);
	if (!acl)
		return gfs2_setattr_simple(ip, attr);

	clone = posix_acl_clone(acl, GFP_NOFS);
	error = -ENOMEM;
	if (!clone)
		goto out;
	posix_acl_release(acl);
	acl = clone;

	error = posix_acl_chmod_masq(acl, attr->ia_mode);
	if (!error) {
		len = posix_acl_to_xattr(acl, NULL, 0);
		data = kmalloc(len, GFP_NOFS);
		error = -ENOMEM;
		if (data == NULL)
			goto out;
		posix_acl_to_xattr(acl, data, len);
		error = gfs2_xattr_acl_chmod(ip, attr, data);
		kfree(data);
		set_cached_acl(&ip->i_inode, ACL_TYPE_ACCESS, acl);
	}

out:
	posix_acl_release(acl);
	return error;
}

static int gfs2_acl_type(const char *name)
{
	if (strcmp(name, GFS2_POSIX_ACL_ACCESS) == 0)
		return ACL_TYPE_ACCESS;
	if (strcmp(name, GFS2_POSIX_ACL_DEFAULT) == 0)
		return ACL_TYPE_DEFAULT;
	return -EINVAL;
}

static int gfs2_xattr_system_get(struct dentry *dentry, const char *name,
				 void *buffer, size_t size, int xtype)
{
	struct inode *inode = dentry->d_inode;
	struct posix_acl *acl;
	int type;
	int error;

	type = gfs2_acl_type(name);
	if (type < 0)
		return type;

	acl = gfs2_acl_get(GFS2_I(inode), type);
	if (IS_ERR(acl))
		return PTR_ERR(acl);
	if (acl == NULL)
		return -ENODATA;

	error = posix_acl_to_xattr(acl, buffer, size);
	posix_acl_release(acl);

	return error;
}

static int gfs2_xattr_system_set(struct dentry *dentry, const char *name,
				 const void *value, size_t size, int flags,
				 int xtype)
{
	struct inode *inode = dentry->d_inode;
	struct gfs2_sbd *sdp = GFS2_SB(inode);
	struct posix_acl *acl = NULL;
	int error = 0, type;

	if (!sdp->sd_args.ar_posix_acl)
		return -EOPNOTSUPP;

	type = gfs2_acl_type(name);
	if (type < 0)
		return type;
	if (flags & XATTR_CREATE)
		return -EINVAL;
	if (type == ACL_TYPE_DEFAULT && !S_ISDIR(inode->i_mode))
		return value ? -EACCES : 0;
	if ((current_fsuid() != inode->i_uid) && !capable(CAP_FOWNER))
		return -EPERM;
	if (S_ISLNK(inode->i_mode))
		return -EOPNOTSUPP;

	if (!value)
		goto set_acl;

	acl = posix_acl_from_xattr(value, size);
	if (!acl) {
		/*
		 * acl_set_file(3) may request that we set default ACLs with
		 * zero length -- defend (gracefully) against that here.
		 */
		goto out;
	}
	if (IS_ERR(acl)) {
		error = PTR_ERR(acl);
		goto out;
	}

	error = posix_acl_valid(acl);
	if (error)
		goto out_release;

	error = -EINVAL;
	if (acl->a_count > GFS2_ACL_MAX_ENTRIES)
		goto out_release;

	if (type == ACL_TYPE_ACCESS) {
		mode_t mode = inode->i_mode;
		error = posix_acl_equiv_mode(acl, &mode);

		if (error <= 0) {
			posix_acl_release(acl);
			acl = NULL;

			if (error < 0)
				return error;
		}

		error = gfs2_set_mode(inode, mode);
		if (error)
			goto out_release;
	}

set_acl:
	error = __gfs2_xattr_set(inode, name, value, size, 0, GFS2_EATYPE_SYS);
	if (!error) {
		if (acl)
			set_cached_acl(inode, type, acl);
		else
			forget_cached_acl(inode, type);
	}
out_release:
	posix_acl_release(acl);
out:
	return error;
}

struct xattr_handler gfs2_xattr_system_handler = {
	.prefix = XATTR_SYSTEM_PREFIX,
	.flags  = GFS2_EATYPE_SYS,
	.get    = gfs2_xattr_system_get,
	.set    = gfs2_xattr_system_set,
};