1 /* RxRPC key management
2 *
3 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
10 *
11 * RxRPC keys should have a description of describing their purpose:
12 * "afs@CAMBRIDGE.REDHAT.COM>
13 */
14
15 #include <linux/module.h>
16 #include <linux/net.h>
17 #include <linux/skbuff.h>
18 #include <linux/key-type.h>
19 #include <linux/crypto.h>
20 #include <net/sock.h>
21 #include <net/af_rxrpc.h>
22 #include <keys/rxrpc-type.h>
23 #include <keys/user-type.h>
24 #include "ar-internal.h"
25
26 static int rxrpc_instantiate(struct key *, const void *, size_t);
27 static int rxrpc_instantiate_s(struct key *, const void *, size_t);
28 static void rxrpc_destroy(struct key *);
29 static void rxrpc_destroy_s(struct key *);
30 static void rxrpc_describe(const struct key *, struct seq_file *);
31
32 /*
33 * rxrpc defined keys take an arbitrary string as the description and an
34 * arbitrary blob of data as the payload
35 */
36 struct key_type key_type_rxrpc = {
37 .name = "rxrpc",
38 .instantiate = rxrpc_instantiate,
39 .match = user_match,
40 .destroy = rxrpc_destroy,
41 .describe = rxrpc_describe,
42 };
43 EXPORT_SYMBOL(key_type_rxrpc);
44
45 /*
46 * rxrpc server defined keys take "<serviceId>:<securityIndex>" as the
47 * description and an 8-byte decryption key as the payload
48 */
49 struct key_type key_type_rxrpc_s = {
50 .name = "rxrpc_s",
51 .instantiate = rxrpc_instantiate_s,
52 .match = user_match,
53 .destroy = rxrpc_destroy_s,
54 .describe = rxrpc_describe,
55 };
56
57 /*
58 * instantiate an rxrpc defined key
59 * data should be of the form:
60 * OFFSET LEN CONTENT
61 * 0 4 key interface version number
62 * 4 2 security index (type)
63 * 6 2 ticket length
64 * 8 4 key expiry time (time_t)
65 * 12 4 kvno
66 * 16 8 session key
67 * 24 [len] ticket
68 *
69 * if no data is provided, then a no-security key is made
70 */
rxrpc_instantiate(struct key * key,const void * data,size_t datalen)71 static int rxrpc_instantiate(struct key *key, const void *data, size_t datalen)
72 {
73 const struct rxkad_key *tsec;
74 struct rxrpc_key_payload *upayload;
75 size_t plen;
76 u32 kver;
77 int ret;
78
79 _enter("{%x},,%zu", key_serial(key), datalen);
80
81 /* handle a no-security key */
82 if (!data && datalen == 0)
83 return 0;
84
85 /* get the key interface version number */
86 ret = -EINVAL;
87 if (datalen <= 4 || !data)
88 goto error;
89 memcpy(&kver, data, sizeof(kver));
90 data += sizeof(kver);
91 datalen -= sizeof(kver);
92
93 _debug("KEY I/F VERSION: %u", kver);
94
95 ret = -EKEYREJECTED;
96 if (kver != 1)
97 goto error;
98
99 /* deal with a version 1 key */
100 ret = -EINVAL;
101 if (datalen < sizeof(*tsec))
102 goto error;
103
104 tsec = data;
105 if (datalen != sizeof(*tsec) + tsec->ticket_len)
106 goto error;
107
108 _debug("SCIX: %u", tsec->security_index);
109 _debug("TLEN: %u", tsec->ticket_len);
110 _debug("EXPY: %x", tsec->expiry);
111 _debug("KVNO: %u", tsec->kvno);
112 _debug("SKEY: %02x%02x%02x%02x%02x%02x%02x%02x",
113 tsec->session_key[0], tsec->session_key[1],
114 tsec->session_key[2], tsec->session_key[3],
115 tsec->session_key[4], tsec->session_key[5],
116 tsec->session_key[6], tsec->session_key[7]);
117 if (tsec->ticket_len >= 8)
118 _debug("TCKT: %02x%02x%02x%02x%02x%02x%02x%02x",
119 tsec->ticket[0], tsec->ticket[1],
120 tsec->ticket[2], tsec->ticket[3],
121 tsec->ticket[4], tsec->ticket[5],
122 tsec->ticket[6], tsec->ticket[7]);
123
124 ret = -EPROTONOSUPPORT;
125 if (tsec->security_index != 2)
126 goto error;
127
128 key->type_data.x[0] = tsec->security_index;
129
130 plen = sizeof(*upayload) + tsec->ticket_len;
131 ret = key_payload_reserve(key, plen);
132 if (ret < 0)
133 goto error;
134
135 ret = -ENOMEM;
136 upayload = kmalloc(plen, GFP_KERNEL);
137 if (!upayload)
138 goto error;
139
140 /* attach the data */
141 memcpy(&upayload->k, tsec, sizeof(*tsec));
142 memcpy(&upayload->k.ticket, (void *)tsec + sizeof(*tsec),
143 tsec->ticket_len);
144 key->payload.data = upayload;
145 key->expiry = tsec->expiry;
146 ret = 0;
147
148 error:
149 return ret;
150 }
151
152 /*
153 * instantiate a server secret key
154 * data should be a pointer to the 8-byte secret key
155 */
rxrpc_instantiate_s(struct key * key,const void * data,size_t datalen)156 static int rxrpc_instantiate_s(struct key *key, const void *data,
157 size_t datalen)
158 {
159 struct crypto_blkcipher *ci;
160
161 _enter("{%x},,%zu", key_serial(key), datalen);
162
163 if (datalen != 8)
164 return -EINVAL;
165
166 memcpy(&key->type_data, data, 8);
167
168 ci = crypto_alloc_blkcipher("pcbc(des)", 0, CRYPTO_ALG_ASYNC);
169 if (IS_ERR(ci)) {
170 _leave(" = %ld", PTR_ERR(ci));
171 return PTR_ERR(ci);
172 }
173
174 if (crypto_blkcipher_setkey(ci, data, 8) < 0)
175 BUG();
176
177 key->payload.data = ci;
178 _leave(" = 0");
179 return 0;
180 }
181
182 /*
183 * dispose of the data dangling from the corpse of a rxrpc key
184 */
rxrpc_destroy(struct key * key)185 static void rxrpc_destroy(struct key *key)
186 {
187 kfree(key->payload.data);
188 }
189
190 /*
191 * dispose of the data dangling from the corpse of a rxrpc key
192 */
rxrpc_destroy_s(struct key * key)193 static void rxrpc_destroy_s(struct key *key)
194 {
195 if (key->payload.data) {
196 crypto_free_blkcipher(key->payload.data);
197 key->payload.data = NULL;
198 }
199 }
200
201 /*
202 * describe the rxrpc key
203 */
rxrpc_describe(const struct key * key,struct seq_file * m)204 static void rxrpc_describe(const struct key *key, struct seq_file *m)
205 {
206 seq_puts(m, key->description);
207 }
208
209 /*
210 * grab the security key for a socket
211 */
rxrpc_request_key(struct rxrpc_sock * rx,char __user * optval,int optlen)212 int rxrpc_request_key(struct rxrpc_sock *rx, char __user *optval, int optlen)
213 {
214 struct key *key;
215 char *description;
216
217 _enter("");
218
219 if (optlen <= 0 || optlen > PAGE_SIZE - 1)
220 return -EINVAL;
221
222 description = kmalloc(optlen + 1, GFP_KERNEL);
223 if (!description)
224 return -ENOMEM;
225
226 if (copy_from_user(description, optval, optlen)) {
227 kfree(description);
228 return -EFAULT;
229 }
230 description[optlen] = 0;
231
232 key = request_key(&key_type_rxrpc, description, NULL);
233 if (IS_ERR(key)) {
234 kfree(description);
235 _leave(" = %ld", PTR_ERR(key));
236 return PTR_ERR(key);
237 }
238
239 rx->key = key;
240 kfree(description);
241 _leave(" = 0 [key %x]", key->serial);
242 return 0;
243 }
244
245 /*
246 * grab the security keyring for a server socket
247 */
rxrpc_server_keyring(struct rxrpc_sock * rx,char __user * optval,int optlen)248 int rxrpc_server_keyring(struct rxrpc_sock *rx, char __user *optval,
249 int optlen)
250 {
251 struct key *key;
252 char *description;
253
254 _enter("");
255
256 if (optlen <= 0 || optlen > PAGE_SIZE - 1)
257 return -EINVAL;
258
259 description = kmalloc(optlen + 1, GFP_KERNEL);
260 if (!description)
261 return -ENOMEM;
262
263 if (copy_from_user(description, optval, optlen)) {
264 kfree(description);
265 return -EFAULT;
266 }
267 description[optlen] = 0;
268
269 key = request_key(&key_type_keyring, description, NULL);
270 if (IS_ERR(key)) {
271 kfree(description);
272 _leave(" = %ld", PTR_ERR(key));
273 return PTR_ERR(key);
274 }
275
276 rx->securities = key;
277 kfree(description);
278 _leave(" = 0 [key %x]", key->serial);
279 return 0;
280 }
281
282 /*
283 * generate a server data key
284 */
rxrpc_get_server_data_key(struct rxrpc_connection * conn,const void * session_key,time_t expiry,u32 kvno)285 int rxrpc_get_server_data_key(struct rxrpc_connection *conn,
286 const void *session_key,
287 time_t expiry,
288 u32 kvno)
289 {
290 const struct cred *cred = current_cred();
291 struct key *key;
292 int ret;
293
294 struct {
295 u32 kver;
296 struct rxkad_key tsec;
297 } data;
298
299 _enter("");
300
301 key = key_alloc(&key_type_rxrpc, "x", 0, 0, cred, 0,
302 KEY_ALLOC_NOT_IN_QUOTA);
303 if (IS_ERR(key)) {
304 _leave(" = -ENOMEM [alloc %ld]", PTR_ERR(key));
305 return -ENOMEM;
306 }
307
308 _debug("key %d", key_serial(key));
309
310 data.kver = 1;
311 data.tsec.security_index = 2;
312 data.tsec.ticket_len = 0;
313 data.tsec.expiry = expiry;
314 data.tsec.kvno = 0;
315
316 memcpy(&data.tsec.session_key, session_key,
317 sizeof(data.tsec.session_key));
318
319 ret = key_instantiate_and_link(key, &data, sizeof(data), NULL, NULL);
320 if (ret < 0)
321 goto error;
322
323 conn->key = key;
324 _leave(" = 0 [%d]", key_serial(key));
325 return 0;
326
327 error:
328 key_revoke(key);
329 key_put(key);
330 _leave(" = -ENOMEM [ins %d]", ret);
331 return -ENOMEM;
332 }
333 EXPORT_SYMBOL(rxrpc_get_server_data_key);
334
335 /**
336 * rxrpc_get_null_key - Generate a null RxRPC key
337 * @keyname: The name to give the key.
338 *
339 * Generate a null RxRPC key that can be used to indicate anonymous security is
340 * required for a particular domain.
341 */
rxrpc_get_null_key(const char * keyname)342 struct key *rxrpc_get_null_key(const char *keyname)
343 {
344 const struct cred *cred = current_cred();
345 struct key *key;
346 int ret;
347
348 key = key_alloc(&key_type_rxrpc, keyname, 0, 0, cred,
349 KEY_POS_SEARCH, KEY_ALLOC_NOT_IN_QUOTA);
350 if (IS_ERR(key))
351 return key;
352
353 ret = key_instantiate_and_link(key, NULL, 0, NULL, NULL);
354 if (ret < 0) {
355 key_revoke(key);
356 key_put(key);
357 return ERR_PTR(ret);
358 }
359
360 return key;
361 }
362 EXPORT_SYMBOL(rxrpc_get_null_key);
363