1/*
  2 * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
  3 * Copyright (C) 2004-2006 Red Hat, Inc.  All rights reserved.
  4 *
  5 * This copyrighted material is made available to anyone wishing to use,
  6 * modify, copy, or redistribute it subject to the terms and conditions
  7 * of the GNU General Public License version 2.
  8 */
  9
 10#include <linux/sched.h>
 11#include <linux/slab.h>
 12#include <linux/spinlock.h>
 13#include <linux/completion.h>
 14#include <linux/buffer_head.h>
 15#include <linux/xattr.h>
 16#include <linux/posix_acl.h>
 17#include <linux/posix_acl_xattr.h>
 18#include <linux/gfs2_ondisk.h>
 19
 20#include "gfs2.h"
 21#include "incore.h"
 22#include "acl.h"
 23#include "xattr.h"
 24#include "glock.h"
 25#include "inode.h"
 26#include "meta_io.h"
 27#include "trans.h"
 28#include "util.h"
 29
 30static const char *gfs2_acl_name(int type)
 31{
 32	switch (type) {
 33	case ACL_TYPE_ACCESS:
 34		return GFS2_POSIX_ACL_ACCESS;
 35	case ACL_TYPE_DEFAULT:
 36		return GFS2_POSIX_ACL_DEFAULT;
 37	}
 38	return NULL;
 39}
 40
 41struct posix_acl *gfs2_get_acl(struct inode *inode, int type)
 42{
 43	struct gfs2_inode *ip = GFS2_I(inode);
 44	struct posix_acl *acl;
 45	const char *name;
 46	char *data;
 47	int len;
 48
 49	if (!ip->i_eattr)
 50		return NULL;
 51
 52	acl = get_cached_acl(&ip->i_inode, type);
 53	if (acl != ACL_NOT_CACHED)
 54		return acl;
 55
 56	name = gfs2_acl_name(type);
 57	if (name == NULL)
 58		return ERR_PTR(-EINVAL);
 59
 60	len = gfs2_xattr_acl_get(ip, name, &data);
 61	if (len < 0)
 62		return ERR_PTR(len);
 63	if (len == 0)
 64		return NULL;
 65
 66	acl = posix_acl_from_xattr(data, len);
 67	kfree(data);
 68	return acl;
 69}
 70
 71static int gfs2_set_mode(struct inode *inode, umode_t mode)
 72{
 73	int error = 0;
 74
 75	if (mode != inode->i_mode) {
 76		inode->i_mode = mode;
 77		mark_inode_dirty(inode);
 78	}
 79
 80	return error;
 81}
 82
 83static int gfs2_acl_set(struct inode *inode, int type, struct posix_acl *acl)
 84{
 85	int error;
 86	int len;
 87	char *data;
 88	const char *name = gfs2_acl_name(type);
 89
 90	BUG_ON(name == NULL);
 91	len = posix_acl_to_xattr(acl, NULL, 0);
 92	if (len == 0)
 93		return 0;
 94	data = kmalloc(len, GFP_NOFS);
 95	if (data == NULL)
 96		return -ENOMEM;
 97	error = posix_acl_to_xattr(acl, data, len);
 98	if (error < 0)
 99		goto out;
100	error = __gfs2_xattr_set(inode, name, data, len, 0, GFS2_EATYPE_SYS);
101	if (!error)
102		set_cached_acl(inode, type, acl);
103out:
104	kfree(data);
105	return error;
106}
107
108int gfs2_acl_create(struct gfs2_inode *dip, struct inode *inode)
109{
110	struct gfs2_sbd *sdp = GFS2_SB(&dip->i_inode);
111	struct posix_acl *acl;
112	umode_t mode = inode->i_mode;
113	int error = 0;
114
115	if (!sdp->sd_args.ar_posix_acl)
116		return 0;
117	if (S_ISLNK(inode->i_mode))
118		return 0;
119
120	acl = gfs2_get_acl(&dip->i_inode, ACL_TYPE_DEFAULT);
121	if (IS_ERR(acl))
122		return PTR_ERR(acl);
123	if (!acl) {
124		mode &= ~current_umask();
125		return gfs2_set_mode(inode, mode);
126	}
127
128	if (S_ISDIR(inode->i_mode)) {
129		error = gfs2_acl_set(inode, ACL_TYPE_DEFAULT, acl);
130		if (error)
131			goto out;
132	}
133
134	error = posix_acl_create(&acl, GFP_NOFS, &mode);
135	if (error < 0)
136		return error;
137
138	if (error == 0)
139		goto munge;
140
141	error = gfs2_acl_set(inode, ACL_TYPE_ACCESS, acl);
142	if (error)
143		goto out;
144munge:
145	error = gfs2_set_mode(inode, mode);
146out:
147	posix_acl_release(acl);
148	return error;
149}
150
151int gfs2_acl_chmod(struct gfs2_inode *ip, struct iattr *attr)
152{
153	struct inode *inode = &ip->i_inode;
154	struct posix_acl *acl;
155	char *data;
156	unsigned int len;
157	int error;
158
159	acl = gfs2_get_acl(&ip->i_inode, ACL_TYPE_ACCESS);
160	if (IS_ERR(acl))
161		return PTR_ERR(acl);
162	if (!acl)
163		return gfs2_setattr_simple(inode, attr);
164
165	error = posix_acl_chmod(&acl, GFP_NOFS, attr->ia_mode);
166	if (error)
167		return error;
168
169	len = posix_acl_to_xattr(acl, NULL, 0);
170	data = kmalloc(len, GFP_NOFS);
171	error = -ENOMEM;
172	if (data == NULL)
173		goto out;
174	posix_acl_to_xattr(acl, data, len);
175	error = gfs2_xattr_acl_chmod(ip, attr, data);
176	kfree(data);
177	set_cached_acl(&ip->i_inode, ACL_TYPE_ACCESS, acl);
178
179out:
180	posix_acl_release(acl);
181	return error;
182}
183
184static int gfs2_acl_type(const char *name)
185{
186	if (strcmp(name, GFS2_POSIX_ACL_ACCESS) == 0)
187		return ACL_TYPE_ACCESS;
188	if (strcmp(name, GFS2_POSIX_ACL_DEFAULT) == 0)
189		return ACL_TYPE_DEFAULT;
190	return -EINVAL;
191}
192
193static int gfs2_xattr_system_get(struct dentry *dentry, const char *name,
194				 void *buffer, size_t size, int xtype)
195{
196	struct inode *inode = dentry->d_inode;
197	struct gfs2_sbd *sdp = GFS2_SB(inode);
198	struct posix_acl *acl;
199	int type;
200	int error;
201
202	if (!sdp->sd_args.ar_posix_acl)
203		return -EOPNOTSUPP;
204
205	type = gfs2_acl_type(name);
206	if (type < 0)
207		return type;
208
209	acl = gfs2_get_acl(inode, type);
210	if (IS_ERR(acl))
211		return PTR_ERR(acl);
212	if (acl == NULL)
213		return -ENODATA;
214
215	error = posix_acl_to_xattr(acl, buffer, size);
216	posix_acl_release(acl);
217
218	return error;
219}
220
221static int gfs2_xattr_system_set(struct dentry *dentry, const char *name,
222				 const void *value, size_t size, int flags,
223				 int xtype)
224{
225	struct inode *inode = dentry->d_inode;
226	struct gfs2_sbd *sdp = GFS2_SB(inode);
227	struct posix_acl *acl = NULL;
228	int error = 0, type;
229
230	if (!sdp->sd_args.ar_posix_acl)
231		return -EOPNOTSUPP;
232
233	type = gfs2_acl_type(name);
234	if (type < 0)
235		return type;
236	if (flags & XATTR_CREATE)
237		return -EINVAL;
238	if (type == ACL_TYPE_DEFAULT && !S_ISDIR(inode->i_mode))
239		return value ? -EACCES : 0;
240	if ((current_fsuid() != inode->i_uid) && !capable(CAP_FOWNER))
241		return -EPERM;
242	if (S_ISLNK(inode->i_mode))
243		return -EOPNOTSUPP;
244
245	if (!value)
246		goto set_acl;
247
248	acl = posix_acl_from_xattr(value, size);
249	if (!acl) {
250		/*
251		 * acl_set_file(3) may request that we set default ACLs with
252		 * zero length -- defend (gracefully) against that here.
253		 */
254		goto out;
255	}
256	if (IS_ERR(acl)) {
257		error = PTR_ERR(acl);
258		goto out;
259	}
260
261	error = posix_acl_valid(acl);
262	if (error)
263		goto out_release;
264
265	error = -EINVAL;
266	if (acl->a_count > GFS2_ACL_MAX_ENTRIES)
267		goto out_release;
268
269	if (type == ACL_TYPE_ACCESS) {
270		umode_t mode = inode->i_mode;
271		error = posix_acl_equiv_mode(acl, &mode);
272
273		if (error <= 0) {
274			posix_acl_release(acl);
275			acl = NULL;
276
277			if (error < 0)
278				return error;
279		}
280
281		error = gfs2_set_mode(inode, mode);
282		if (error)
283			goto out_release;
284	}
285
286set_acl:
287	error = __gfs2_xattr_set(inode, name, value, size, 0, GFS2_EATYPE_SYS);
288	if (!error) {
289		if (acl)
290			set_cached_acl(inode, type, acl);
291		else
292			forget_cached_acl(inode, type);
293	}
294out_release:
295	posix_acl_release(acl);
296out:
297	return error;
298}
299
300const struct xattr_handler gfs2_xattr_system_handler = {
301	.prefix = XATTR_SYSTEM_PREFIX,
302	.flags  = GFS2_EATYPE_SYS,
303	.get    = gfs2_xattr_system_get,
304	.set    = gfs2_xattr_system_set,
305};
306