aboutsummaryrefslogtreecommitdiffstats
path: root/net/rxrpc/ar-key.c
blob: ad8c7a782da1f0daabcd7ff1f9076e1785ae0f23 (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
/* RxRPC key management
 *
 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version
 * 2 of the License, or (at your option) any later version.
 *
 * RxRPC keys should have a description of describing their purpose:
 *	"afs@CAMBRIDGE.REDHAT.COM>
 */

#include <linux/module.h>
#include <linux/net.h>
#include <linux/skbuff.h>
#include <linux/key-type.h>
#include <linux/crypto.h>
#include <net/sock.h>
#include <net/af_rxrpc.h>
#include <keys/rxrpc-type.h>
#include <keys/user-type.h>
#include "ar-internal.h"

static int rxrpc_instantiate(struct key *, const void *, size_t);
static int rxrpc_instantiate_s(struct key *, const void *, size_t);
static void rxrpc_destroy(struct key *);
static void rxrpc_destroy_s(struct key *);
static void rxrpc_describe(const struct key *, struct seq_file *);

/*
 * rxrpc defined keys take an arbitrary string as the description and an
 * arbitrary blob of data as the payload
 */
struct key_type key_type_rxrpc = {
	.name		= "rxrpc",
	.instantiate	= rxrpc_instantiate,
	.match		= user_match,
	.destroy	= rxrpc_destroy,
	.describe	= rxrpc_describe,
};
EXPORT_SYMBOL(key_type_rxrpc);

/*
 * rxrpc server defined keys take "<serviceId>:<securityIndex>" as the
 * description and an 8-byte decryption key as the payload
 */
struct key_type key_type_rxrpc_s = {
	.name		= "rxrpc_s",
	.instantiate	= rxrpc_instantiate_s,
	.match		= user_match,
	.destroy	= rxrpc_destroy_s,
	.describe	= rxrpc_describe,
};

/*
 * instantiate an rxrpc defined key
 * data should be of the form:
 *	OFFSET	LEN	CONTENT
 *	0	4	key interface version number
 *	4	2	security index (type)
 *	6	2	ticket length
 *	8	4	key expiry time (time_t)
 *	12	4	kvno
 *	16	8	session key
 *	24	[len]	ticket
 *
 * if no data is provided, then a no-security key is made
 */
static int rxrpc_instantiate(struct key *key, const void *data, size_t datalen)
{
	const struct rxkad_key *tsec;
	struct rxrpc_key_payload *upayload;
	size_t plen;
	u32 kver;
	int ret;

	_enter("{%x},,%zu", key_serial(key), datalen);

	/* handle a no-security key */
	if (!data && datalen == 0)
		return 0;

	/* get the key interface version number */
	ret = -EINVAL;
	if (datalen <= 4 || !data)
		goto error;
	memcpy(&kver, data, sizeof(kver));
	data += sizeof(kver);
	datalen -= sizeof(kver);

	_debug("KEY I/F VERSION: %u", kver);

	ret = -EKEYREJECTED;
	if (kver != 1)
		goto error;

	/* deal with a version 1 key */
	ret = -EINVAL;
	if (datalen < sizeof(*tsec))
		goto error;

	tsec = data;
	if (datalen != sizeof(*tsec) + tsec->ticket_len)
		goto error;

	_debug("SCIX: %u", tsec->security_index);
	_debug("TLEN: %u", tsec->ticket_len);
	_debug("EXPY: %x", tsec->expiry);
	_debug("KVNO: %u", tsec->kvno);
	_debug("SKEY: %02x%02x%02x%02x%02x%02x%02x%02x",
	       tsec->session_key[0], tsec->session_key[1],
	       tsec->session_key[2], tsec->session_key[3],
	       tsec->session_key[4], tsec->session_key[5],
	       tsec->session_key[6], tsec->session_key[7]);
	if (tsec->ticket_len >= 8)
		_debug("TCKT: %02x%02x%02x%02x%02x%02x%02x%02x",
		       tsec->ticket[0], tsec->ticket[1],
		       tsec->ticket[2], tsec->ticket[3],
		       tsec->ticket[4], tsec->ticket[5],
		       tsec->ticket[6], tsec->ticket[7]);

	ret = -EPROTONOSUPPORT;
	if (tsec->security_index != 2)
		goto error;

	key->type_data.x[0] = tsec->security_index;

	plen = sizeof(*upayload) + tsec->ticket_len;
	ret = key_payload_reserve(key, plen);
	if (ret < 0)
		goto error;

	ret = -ENOMEM;
	upayload = kmalloc(plen, GFP_KERNEL);
	if (!upayload)
		goto error;

	/* attach the data */
	memcpy(&upayload->k, tsec, sizeof(*tsec));
	memcpy(&upayload->k.ticket, (void *)tsec + sizeof(*tsec),
	       tsec->ticket_len);
	key->payload.data = upayload;
	key->expiry = tsec->expiry;
	ret = 0;

error:
	return ret;
}

/*
 * instantiate a server secret key
 * data should be a pointer to the 8-byte secret key
 */
static int rxrpc_instantiate_s(struct key *key, const void *data,
			       size_t datalen)
{
	struct crypto_blkcipher *ci;

	_enter("{%x},,%zu", key_serial(key), datalen);

	if (datalen != 8)
		return -EINVAL;

	memcpy(&key->type_data, data, 8);

	ci = crypto_alloc_blkcipher("pcbc(des)", 0, CRYPTO_ALG_ASYNC);
	if (IS_ERR(ci)) {
		_leave(" = %ld", PTR_ERR(ci));
		return PTR_ERR(ci);
	}

	if (crypto_blkcipher_setkey(ci, data, 8) < 0)
		BUG();

	key->payload.data = ci;
	_leave(" = 0");
	return 0;
}

/*
 * dispose of the data dangling from the corpse of a rxrpc key
 */
static void rxrpc_destroy(struct key *key)
{
	kfree(key->payload.data);
}

/*
 * dispose of the data dangling from the corpse of a rxrpc key
 */
static void rxrpc_destroy_s(struct key *key)
{
	if (key->payload.data) {
		crypto_free_blkcipher(key->payload.data);
		key->payload.data = NULL;
	}
}

/*
 * describe the rxrpc key
 */
static void rxrpc_describe(const struct key *key, struct seq_file *m)
{
	seq_puts(m, key->description);
}

/*
 * grab the security key for a socket
 */
int rxrpc_request_key(struct rxrpc_sock *rx, char __user *optval, int optlen)
{
	struct key *key;
	char *description;

	_enter("");

	if (optlen <= 0 || optlen > PAGE_SIZE - 1)
		return -EINVAL;

	description = kmalloc(optlen + 1, GFP_KERNEL);
	if (!description)
		return -ENOMEM;

	if (copy_from_user(description, optval, optlen)) {
		kfree(description);
		return -EFAULT;
	}
	description[optlen] = 0;

	key = request_key(&key_type_rxrpc, description, NULL);
	if (IS_ERR(key)) {
		kfree(description);
		_leave(" = %ld", PTR_ERR(key));
		return PTR_ERR(key);
	}

	rx->key = key;
	kfree(description);
	_leave(" = 0 [key %x]", key->serial);
	return 0;
}

/*
 * grab the security keyring for a server socket
 */
int rxrpc_server_keyring(struct rxrpc_sock *rx, char __user *optval,
			 int optlen)
{
	struct key *key;
	char *description;

	_enter("");

	if (optlen <= 0 || optlen > PAGE_SIZE - 1)
		return -EINVAL;

	description = kmalloc(optlen + 1, GFP_KERNEL);
	if (!description)
		return -ENOMEM;

	if (copy_from_user(description, optval, optlen)) {
		kfree(description);
		return -EFAULT;
	}
	description[optlen] = 0;

	key = request_key(&key_type_keyring, description, NULL);
	if (IS_ERR(key)) {
		kfree(description);
		_leave(" = %ld", PTR_ERR(key));
		return PTR_ERR(key);
	}

	rx->securities = key;
	kfree(description);
	_leave(" = 0 [key %x]", key->serial);
	return 0;
}

/*
 * generate a server data key
 */
int rxrpc_get_server_data_key(struct rxrpc_connection *conn,
			      const void *session_key,
			      time_t expiry,
			      u32 kvno)
{
	const struct cred *cred = current_cred();
	struct key *key;
	int ret;

	struct {
		u32 kver;
		struct rxkad_key tsec;
	} data;

	_enter("");

	key = key_alloc(&key_type_rxrpc, "x", 0, 0, cred, 0,
			KEY_ALLOC_NOT_IN_QUOTA);
	if (IS_ERR(key)) {
		_leave(" = -ENOMEM [alloc %ld]", PTR_ERR(key));
		return -ENOMEM;
	}

	_debug("key %d", key_serial(key));

	data.kver = 1;
	data.tsec.security_index = 2;
	data.tsec.ticket_len = 0;
	data.tsec.expiry = expiry;
	data.tsec.kvno = 0;

	memcpy(&data.tsec.session_key, session_key,
	       sizeof(data.tsec.session_key));

	ret = key_instantiate_and_link(key, &data, sizeof(data), NULL, NULL);
	if (ret < 0)
		goto error;

	conn->key = key;
	_leave(" = 0 [%d]", key_serial(key));
	return 0;

error:
	key_revoke(key);
	key_put(key);
	_leave(" = -ENOMEM [ins %d]", ret);
	return -ENOMEM;
}
EXPORT_SYMBOL(rxrpc_get_server_data_key);

/**
 * rxrpc_get_null_key - Generate a null RxRPC key
 * @keyname: The name to give the key.
 *
 * Generate a null RxRPC key that can be used to indicate anonymous security is
 * required for a particular domain.
 */
struct key *rxrpc_get_null_key(const char *keyname)
{
	const struct cred *cred = current_cred();
	struct key *key;
	int ret;

	key = key_alloc(&key_type_rxrpc, keyname, 0, 0, cred,
			KEY_POS_SEARCH, KEY_ALLOC_NOT_IN_QUOTA);
	if (IS_ERR(key))
		return key;

	ret = key_instantiate_and_link(key, NULL, 0, NULL, NULL);
	if (ret < 0) {
		key_revoke(key);
		key_put(key);
		return ERR_PTR(ret);
	}

	return key;
}
EXPORT_SYMBOL(rxrpc_get_null_key);