aboutsummaryrefslogtreecommitdiff
path: root/fs/9p/acl.c
blob: 7350f53f3b51bb53b5f8d3cdc9d9c876b29afaf5 (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
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
/*
 * Copyright IBM Corporation, 2010
 * Author Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of version 2.1 of the GNU Lesser General Public License
 * as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it would be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 *
 */

#include <linux/module.h>
#include <linux/fs.h>
#include <net/9p/9p.h>
#include <net/9p/client.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/posix_acl_xattr.h>
#include "xattr.h"
#include "acl.h"
#include "v9fs.h"
#include "v9fs_vfs.h"

static struct posix_acl *__v9fs_get_acl(struct p9_fid *fid, char *name)
{
	ssize_t size;
	void *value = NULL;
	struct posix_acl *acl = NULL;

	size = v9fs_fid_xattr_get(fid, name, NULL, 0);
	if (size > 0) {
		value = kzalloc(size, GFP_NOFS);
		if (!value)
			return ERR_PTR(-ENOMEM);
		size = v9fs_fid_xattr_get(fid, name, value, size);
		if (size > 0) {
			acl = posix_acl_from_xattr(value, size);
			if (IS_ERR(acl))
				goto err_out;
		}
	} else if (size == -ENODATA || size == 0 ||
		   size == -ENOSYS || size == -EOPNOTSUPP) {
		acl = NULL;
	} else
		acl = ERR_PTR(-EIO);

err_out:
	kfree(value);
	return acl;
}

int v9fs_get_acl(struct inode *inode, struct p9_fid *fid)
{
	int retval = 0;
	struct posix_acl *pacl, *dacl;
	struct v9fs_session_info *v9ses;

	v9ses = v9fs_inode2v9ses(inode);
	if (((v9ses->flags & V9FS_ACCESS_MASK) != V9FS_ACCESS_CLIENT) ||
			((v9ses->flags & V9FS_ACL_MASK) != V9FS_POSIX_ACL)) {
		set_cached_acl(inode, ACL_TYPE_DEFAULT, NULL);
		set_cached_acl(inode, ACL_TYPE_ACCESS, NULL);
		return 0;
	}
	/* get the default/access acl values and cache them */
	dacl = __v9fs_get_acl(fid, POSIX_ACL_XATTR_DEFAULT);
	pacl = __v9fs_get_acl(fid, POSIX_ACL_XATTR_ACCESS);

	if (!IS_ERR(dacl) && !IS_ERR(pacl)) {
		set_cached_acl(inode, ACL_TYPE_DEFAULT, dacl);
		set_cached_acl(inode, ACL_TYPE_ACCESS, pacl);
	} else
		retval = -EIO;

	if (!IS_ERR(dacl))
		posix_acl_release(dacl);

	if (!IS_ERR(pacl))
		posix_acl_release(pacl);

	return retval;
}

static struct posix_acl *v9fs_get_cached_acl(struct inode *inode, int type)
{
	struct posix_acl *acl;
	/*
	 * 9p Always cache the acl value when
	 * instantiating the inode (v9fs_inode_from_fid)
	 */
	acl = get_cached_acl(inode, type);
	BUG_ON(acl == ACL_NOT_CACHED);
	return acl;
}

int v9fs_check_acl(struct inode *inode, int mask)
{
	struct posix_acl *acl;
	struct v9fs_session_info *v9ses;

	if (mask & MAY_NOT_BLOCK)
		return -ECHILD;

	v9ses = v9fs_inode2v9ses(inode);
	if (((v9ses->flags & V9FS_ACCESS_MASK) != V9FS_ACCESS_CLIENT) ||
			((v9ses->flags & V9FS_ACL_MASK) != V9FS_POSIX_ACL)) {
		/*
		 * On access = client  and acl = on mode get the acl
		 * values from the server
		 */
		return 0;
	}
	acl = v9fs_get_cached_acl(inode, ACL_TYPE_ACCESS);

	if (IS_ERR(acl))
		return PTR_ERR(acl);
	if (acl) {
		int error = posix_acl_permission(inode, acl, mask);
		posix_acl_release(acl);
		return error;
	}
	return -EAGAIN;
}

static int v9fs_set_acl(struct dentry *dentry, int type, struct posix_acl *acl)
{
	int retval;
	char *name;
	size_t size;
	void *buffer;
	struct inode *inode = dentry->d_inode;

	set_cached_acl(inode, type, acl);

	if (!acl)
		return 0;

	/* Set a setxattr request to server */
	size = posix_acl_xattr_size(acl->a_count);
	buffer = kmalloc(size, GFP_KERNEL);
	if (!buffer)
		return -ENOMEM;
	retval = posix_acl_to_xattr(acl, buffer, size);
	if (retval < 0)
		goto err_free_out;
	switch (type) {
	case ACL_TYPE_ACCESS:
		name = POSIX_ACL_XATTR_ACCESS;
		break;
	case ACL_TYPE_DEFAULT:
		name = POSIX_ACL_XATTR_DEFAULT;
		break;
	default:
		BUG();
	}
	retval = v9fs_xattr_set(dentry, name, buffer, size, 0);
err_free_out:
	kfree(buffer);
	return retval;
}

int v9fs_acl_chmod(struct dentry *dentry)
{
	int retval = 0;
	struct posix_acl *acl, *clone;
	struct inode *inode = dentry->d_inode;

	if (S_ISLNK(inode->i_mode))
		return -EOPNOTSUPP;
	acl = v9fs_get_cached_acl(inode, ACL_TYPE_ACCESS);
	if (acl) {
		clone = posix_acl_clone(acl, GFP_KERNEL);
		posix_acl_release(acl);
		if (!clone)
			return -ENOMEM;
		retval = posix_acl_chmod_masq(clone, inode->i_mode);
		if (!retval)
			retval = v9fs_set_acl(dentry, ACL_TYPE_ACCESS, clone);
		posix_acl_release(clone);
	}
	return retval;
}

int v9fs_set_create_acl(struct dentry *dentry,
			struct posix_acl **dpacl, struct posix_acl **pacl)
{
	if (dentry) {
		v9fs_set_acl(dentry, ACL_TYPE_DEFAULT, *dpacl);
		v9fs_set_acl(dentry, ACL_TYPE_ACCESS, *pacl);
	}
	posix_acl_release(*dpacl);
	posix_acl_release(*pacl);
	*dpacl = *pacl = NULL;
	return 0;
}

int v9fs_acl_mode(struct inode *dir, mode_t *modep,
		  struct posix_acl **dpacl, struct posix_acl **pacl)
{
	int retval = 0;
	mode_t mode = *modep;
	struct posix_acl *acl = NULL;

	if (!S_ISLNK(mode)) {
		acl = v9fs_get_cached_acl(dir, ACL_TYPE_DEFAULT);
		if (IS_ERR(acl))
			return PTR_ERR(acl);
		if (!acl)
			mode &= ~current_umask();
	}
	if (acl) {
		struct posix_acl *clone;

		if (S_ISDIR(mode))
			*dpacl = posix_acl_dup(acl);
		clone = posix_acl_clone(acl, GFP_NOFS);
		posix_acl_release(acl);
		if (!clone)
			return -ENOMEM;

		retval = posix_acl_create_masq(clone, &mode);
		if (retval < 0) {
			posix_acl_release(clone);
			goto cleanup;
		}
		if (retval > 0)
			*pacl = clone;
		else
			posix_acl_release(clone);
	}
	*modep  = mode;
	return 0;
cleanup:
	return retval;

}

static int v9fs_remote_get_acl(struct dentry *dentry, const char *name,
			       void *buffer, size_t size, int type)
{
	char *full_name;

	switch (type) {
	case ACL_TYPE_ACCESS:
		full_name =  POSIX_ACL_XATTR_ACCESS;
		break;
	case ACL_TYPE_DEFAULT:
		full_name = POSIX_ACL_XATTR_DEFAULT;
		break;
	default:
		BUG();
	}
	return v9fs_xattr_get(dentry, full_name, buffer, size);
}

static int v9fs_xattr_get_acl(struct dentry *dentry, const char *name,
			      void *buffer, size_t size, int type)
{
	struct v9fs_session_info *v9ses;
	struct posix_acl *acl;
	int error;

	if (strcmp(name, "") != 0)
		return -EINVAL;

	v9ses = v9fs_dentry2v9ses(dentry);
	/*
	 * We allow set/get/list of acl when access=client is not specified
	 */
	if ((v9ses->flags & V9FS_ACCESS_MASK) != V9FS_ACCESS_CLIENT)
		return v9fs_remote_get_acl(dentry, name, buffer, size, type);

	acl = v9fs_get_cached_acl(dentry->d_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 v9fs_remote_set_acl(struct dentry *dentry, const char *name,
			      const void *value, size_t size,
			      int flags, int type)
{
	char *full_name;

	switch (type) {
	case ACL_TYPE_ACCESS:
		full_name =  POSIX_ACL_XATTR_ACCESS;
		break;
	case ACL_TYPE_DEFAULT:
		full_name = POSIX_ACL_XATTR_DEFAULT;
		break;
	default:
		BUG();
	}
	return v9fs_xattr_set(dentry, full_name, value, size, flags);
}


static int v9fs_xattr_set_acl(struct dentry *dentry, const char *name,
			      const void *value, size_t size,
			      int flags, int type)
{
	int retval;
	struct posix_acl *acl;
	struct v9fs_session_info *v9ses;
	struct inode *inode = dentry->d_inode;

	if (strcmp(name, "") != 0)
		return -EINVAL;

	v9ses = v9fs_dentry2v9ses(dentry);
	/*
	 * set the attribute on the remote. Without even looking at the
	 * xattr value. We leave it to the server to validate
	 */
	if ((v9ses->flags & V9FS_ACCESS_MASK) != V9FS_ACCESS_CLIENT)
		return v9fs_remote_set_acl(dentry, name,
					   value, size, flags, type);

	if (S_ISLNK(inode->i_mode))
		return -EOPNOTSUPP;
	if (!inode_owner_or_capable(inode))
		return -EPERM;
	if (value) {
		/* update the cached acl value */
		acl = posix_acl_from_xattr(value, size);
		if (IS_ERR(acl))
			return PTR_ERR(acl);
		else if (acl) {
			retval = posix_acl_valid(acl);
			if (retval)
				goto err_out;
		}
	} else
		acl = NULL;

	switch (type) {
	case ACL_TYPE_ACCESS:
		name = POSIX_ACL_XATTR_ACCESS;
		if (acl) {
			mode_t mode = inode->i_mode;
			retval = posix_acl_equiv_mode(acl, &mode);
			if (retval < 0)
				goto err_out;
			else {
				struct iattr iattr;
				if (retval == 0) {
					/*
					 * ACL can be represented
					 * by the mode bits. So don't
					 * update ACL.
					 */
					acl = NULL;
					value = NULL;
					size = 0;
				}
				/* Updte the mode bits */
				iattr.ia_mode = ((mode & S_IALLUGO) |
						 (inode->i_mode & ~S_IALLUGO));
				iattr.ia_valid = ATTR_MODE;
				/* FIXME should we update ctime ?
				 * What is the following setxattr update the
				 * mode ?
				 */
				v9fs_vfs_setattr_dotl(dentry, &iattr);
			}
		}
		break;
	case ACL_TYPE_DEFAULT:
		name = POSIX_ACL_XATTR_DEFAULT;
		if (!S_ISDIR(inode->i_mode)) {
			retval = acl ? -EINVAL : 0;
			goto err_out;
		}
		break;
	default:
		BUG();
	}
	retval = v9fs_xattr_set(dentry, name, value, size, flags);
	if (!retval)
		set_cached_acl(inode, type, acl);
err_out:
	posix_acl_release(acl);
	return retval;
}

const struct xattr_handler v9fs_xattr_acl_access_handler = {
	.prefix	= POSIX_ACL_XATTR_ACCESS,
	.flags	= ACL_TYPE_ACCESS,
	.get	= v9fs_xattr_get_acl,
	.set	= v9fs_xattr_set_acl,
};

const struct xattr_handler v9fs_xattr_acl_default_handler = {
	.prefix	= POSIX_ACL_XATTR_DEFAULT,
	.flags	= ACL_TYPE_DEFAULT,
	.get	= v9fs_xattr_get_acl,
	.set	= v9fs_xattr_set_acl,
};