summaryrefslogtreecommitdiff
path: root/fs/xfs/xfs_acl.c
blob: b744c62052b667e1cde8112e0bd01b7bbd54e0d6 (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
// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (c) 2008, Christoph Hellwig
 * All Rights Reserved.
 */
#include "xfs.h"
#include "xfs_shared.h"
#include "xfs_format.h"
#include "xfs_log_format.h"
#include "xfs_trans_resv.h"
#include "xfs_mount.h"
#include "xfs_inode.h"
#include "xfs_da_format.h"
#include "xfs_da_btree.h"
#include "xfs_attr.h"
#include "xfs_trace.h"
#include "xfs_error.h"
#include "xfs_acl.h"
#include "xfs_trans.h"
#include "xfs_xattr.h"

#include <linux/posix_acl_xattr.h>

/*
 * Locking scheme:
 *  - all ACL updates are protected by inode->i_mutex, which is taken before
 *    calling into this file.
 */

STATIC struct posix_acl *
xfs_acl_from_disk(
	struct xfs_mount	*mp,
	const struct xfs_acl	*aclp,
	int			len,
	int			max_entries)
{
	struct posix_acl_entry *acl_e;
	struct posix_acl *acl;
	const struct xfs_acl_entry *ace;
	unsigned int count, i;

	if (len < sizeof(*aclp)) {
		XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp, aclp,
				len);
		return ERR_PTR(-EFSCORRUPTED);
	}

	count = be32_to_cpu(aclp->acl_cnt);
	if (count > max_entries || XFS_ACL_SIZE(count) != len) {
		XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp, aclp,
				len);
		return ERR_PTR(-EFSCORRUPTED);
	}

	acl = posix_acl_alloc(count, GFP_KERNEL);
	if (!acl)
		return ERR_PTR(-ENOMEM);

	for (i = 0; i < count; i++) {
		acl_e = &acl->a_entries[i];
		ace = &aclp->acl_entry[i];

		/*
		 * The tag is 32 bits on disk and 16 bits in core.
		 *
		 * Because every access to it goes through the core
		 * format first this is not a problem.
		 */
		acl_e->e_tag = be32_to_cpu(ace->ae_tag);
		acl_e->e_perm = be16_to_cpu(ace->ae_perm);

		switch (acl_e->e_tag) {
		case ACL_USER:
			acl_e->e_uid = make_kuid(&init_user_ns,
						 be32_to_cpu(ace->ae_id));
			break;
		case ACL_GROUP:
			acl_e->e_gid = make_kgid(&init_user_ns,
						 be32_to_cpu(ace->ae_id));
			break;
		case ACL_USER_OBJ:
		case ACL_GROUP_OBJ:
		case ACL_MASK:
		case ACL_OTHER:
			break;
		default:
			goto fail;
		}
	}
	return acl;

fail:
	posix_acl_release(acl);
	return ERR_PTR(-EINVAL);
}

STATIC void
xfs_acl_to_disk(struct xfs_acl *aclp, const struct posix_acl *acl)
{
	const struct posix_acl_entry *acl_e;
	struct xfs_acl_entry *ace;
	int i;

	aclp->acl_cnt = cpu_to_be32(acl->a_count);
	for (i = 0; i < acl->a_count; i++) {
		ace = &aclp->acl_entry[i];
		acl_e = &acl->a_entries[i];

		ace->ae_tag = cpu_to_be32(acl_e->e_tag);
		switch (acl_e->e_tag) {
		case ACL_USER:
			ace->ae_id = cpu_to_be32(
					from_kuid(&init_user_ns, acl_e->e_uid));
			break;
		case ACL_GROUP:
			ace->ae_id = cpu_to_be32(
					from_kgid(&init_user_ns, acl_e->e_gid));
			break;
		default:
			ace->ae_id = cpu_to_be32(ACL_UNDEFINED_ID);
			break;
		}

		ace->ae_perm = cpu_to_be16(acl_e->e_perm);
	}
}

struct posix_acl *
xfs_get_acl(struct inode *inode, int type, bool rcu)
{
	struct xfs_inode	*ip = XFS_I(inode);
	struct xfs_mount	*mp = ip->i_mount;
	struct posix_acl	*acl = NULL;
	struct xfs_da_args	args = {
		.dp		= ip,
		.attr_filter	= XFS_ATTR_ROOT,
		.valuelen	= XFS_ACL_MAX_SIZE(mp),
	};
	int			error;

	if (rcu)
		return ERR_PTR(-ECHILD);

	trace_xfs_get_acl(ip);

	switch (type) {
	case ACL_TYPE_ACCESS:
		args.name = SGI_ACL_FILE;
		break;
	case ACL_TYPE_DEFAULT:
		args.name = SGI_ACL_DEFAULT;
		break;
	default:
		BUG();
	}
	args.namelen = strlen(args.name);

	/*
	 * If the attribute doesn't exist make sure we have a negative cache
	 * entry, for any other error assume it is transient.
	 */
	error = xfs_attr_get(&args);
	if (!error) {
		acl = xfs_acl_from_disk(mp, args.value, args.valuelen,
					XFS_ACL_MAX_ENTRIES(mp));
	} else if (error != -ENOATTR) {
		acl = ERR_PTR(error);
	}

	kmem_free(args.value);
	return acl;
}

int
__xfs_set_acl(struct inode *inode, struct posix_acl *acl, int type)
{
	struct xfs_inode	*ip = XFS_I(inode);
	struct xfs_da_args	args = {
		.dp		= ip,
		.attr_filter	= XFS_ATTR_ROOT,
	};
	int			error;

	switch (type) {
	case ACL_TYPE_ACCESS:
		args.name = SGI_ACL_FILE;
		break;
	case ACL_TYPE_DEFAULT:
		if (!S_ISDIR(inode->i_mode))
			return acl ? -EACCES : 0;
		args.name = SGI_ACL_DEFAULT;
		break;
	default:
		return -EINVAL;
	}
	args.namelen = strlen(args.name);

	if (acl) {
		args.valuelen = XFS_ACL_SIZE(acl->a_count);
		args.value = kvzalloc(args.valuelen, GFP_KERNEL);
		if (!args.value)
			return -ENOMEM;
		xfs_acl_to_disk(args.value, acl);
	}

	error = xfs_attr_change(&args);
	kmem_free(args.value);

	/*
	 * If the attribute didn't exist to start with that's fine.
	 */
	if (!acl && error == -ENOATTR)
		error = 0;
	if (!error)
		set_cached_acl(inode, type, acl);
	return error;
}

static int
xfs_acl_set_mode(
	struct inode		*inode,
	umode_t			mode)
{
	struct xfs_inode	*ip = XFS_I(inode);
	struct xfs_mount	*mp = ip->i_mount;
	struct xfs_trans	*tp;
	int			error;

	error = xfs_trans_alloc(mp, &M_RES(mp)->tr_ichange, 0, 0, 0, &tp);
	if (error)
		return error;

	xfs_ilock(ip, XFS_ILOCK_EXCL);
	xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
	inode->i_mode = mode;
	inode->i_ctime = current_time(inode);
	xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);

	if (xfs_has_wsync(mp))
		xfs_trans_set_sync(tp);
	return xfs_trans_commit(tp);
}

int
xfs_set_acl(struct user_namespace *mnt_userns, struct inode *inode,
	    struct posix_acl *acl, int type)
{
	umode_t mode;
	bool set_mode = false;
	int error = 0;

	if (!acl)
		goto set_acl;

	error = -E2BIG;
	if (acl->a_count > XFS_ACL_MAX_ENTRIES(XFS_M(inode->i_sb)))
		return error;

	if (type == ACL_TYPE_ACCESS) {
		error = posix_acl_update_mode(mnt_userns, inode, &mode, &acl);
		if (error)
			return error;
		set_mode = true;
	}

 set_acl:
	/*
	 * We set the mode after successfully updating the ACL xattr because the
	 * xattr update can fail at ENOSPC and we don't want to change the mode
	 * if the ACL update hasn't been applied.
	 */
	error =  __xfs_set_acl(inode, acl, type);
	if (!error && set_mode && mode != inode->i_mode)
		error = xfs_acl_set_mode(inode, mode);
	return error;
}

/*
 * Invalidate any cached ACLs if the user has bypassed the ACL interface.
 * We don't validate the content whatsoever so it is caller responsibility to
 * provide data in valid format and ensure i_mode is consistent.
 */
void
xfs_forget_acl(
	struct inode		*inode,
	const char		*name)
{
	if (!strcmp(name, SGI_ACL_FILE))
		forget_cached_acl(inode, ACL_TYPE_ACCESS);
	else if (!strcmp(name, SGI_ACL_DEFAULT))
		forget_cached_acl(inode, ACL_TYPE_DEFAULT);
}