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[linux-2.6.git] / net / rxrpc / ar-security.c
1 /* RxRPC security handling
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
12 #include <linux/module.h>
13 #include <linux/net.h>
14 #include <linux/skbuff.h>
15 #include <linux/udp.h>
16 #include <linux/crypto.h>
17 #include <net/sock.h>
18 #include <net/af_rxrpc.h>
19 #include <keys/rxrpc-type.h>
20 #include "ar-internal.h"
21
22 static LIST_HEAD(rxrpc_security_methods);
23 static DECLARE_RWSEM(rxrpc_security_sem);
24
25 /*
26  * get an RxRPC security module
27  */
28 static struct rxrpc_security *rxrpc_security_get(struct rxrpc_security *sec)
29 {
30         return try_module_get(sec->owner) ? sec : NULL;
31 }
32
33 /*
34  * release an RxRPC security module
35  */
36 static void rxrpc_security_put(struct rxrpc_security *sec)
37 {
38         module_put(sec->owner);
39 }
40
41 /*
42  * look up an rxrpc security module
43  */
44 static struct rxrpc_security *rxrpc_security_lookup(u8 security_index)
45 {
46         struct rxrpc_security *sec = NULL;
47
48         _enter("");
49
50         down_read(&rxrpc_security_sem);
51
52         list_for_each_entry(sec, &rxrpc_security_methods, link) {
53                 if (sec->security_index == security_index) {
54                         if (unlikely(!rxrpc_security_get(sec)))
55                                 break;
56                         goto out;
57                 }
58         }
59
60         sec = NULL;
61 out:
62         up_read(&rxrpc_security_sem);
63         _leave(" = %p [%s]", sec, sec ? sec->name : "");
64         return sec;
65 }
66
67 /**
68  * rxrpc_register_security - register an RxRPC security handler
69  * @sec: security module
70  *
71  * register an RxRPC security handler for use by RxRPC
72  */
73 int rxrpc_register_security(struct rxrpc_security *sec)
74 {
75         struct rxrpc_security *psec;
76         int ret;
77
78         _enter("");
79         down_write(&rxrpc_security_sem);
80
81         ret = -EEXIST;
82         list_for_each_entry(psec, &rxrpc_security_methods, link) {
83                 if (psec->security_index == sec->security_index)
84                         goto out;
85         }
86
87         list_add(&sec->link, &rxrpc_security_methods);
88
89         printk(KERN_NOTICE "RxRPC: Registered security type %d '%s'\n",
90                sec->security_index, sec->name);
91         ret = 0;
92
93 out:
94         up_write(&rxrpc_security_sem);
95         _leave(" = %d", ret);
96         return ret;
97 }
98
99 EXPORT_SYMBOL_GPL(rxrpc_register_security);
100
101 /**
102  * rxrpc_unregister_security - unregister an RxRPC security handler
103  * @sec: security module
104  *
105  * unregister an RxRPC security handler
106  */
107 void rxrpc_unregister_security(struct rxrpc_security *sec)
108 {
109
110         _enter("");
111         down_write(&rxrpc_security_sem);
112         list_del_init(&sec->link);
113         up_write(&rxrpc_security_sem);
114
115         printk(KERN_NOTICE "RxRPC: Unregistered security type %d '%s'\n",
116                sec->security_index, sec->name);
117 }
118
119 EXPORT_SYMBOL_GPL(rxrpc_unregister_security);
120
121 /*
122  * initialise the security on a client connection
123  */
124 int rxrpc_init_client_conn_security(struct rxrpc_connection *conn)
125 {
126         struct rxrpc_key_token *token;
127         struct rxrpc_security *sec;
128         struct key *key = conn->key;
129         int ret;
130
131         _enter("{%d},{%x}", conn->debug_id, key_serial(key));
132
133         if (!key)
134                 return 0;
135
136         ret = key_validate(key);
137         if (ret < 0)
138                 return ret;
139
140         if (!key->payload.data)
141                 return -EKEYREJECTED;
142         token = key->payload.data;
143
144         sec = rxrpc_security_lookup(token->security_index);
145         if (!sec)
146                 return -EKEYREJECTED;
147         conn->security = sec;
148
149         ret = conn->security->init_connection_security(conn);
150         if (ret < 0) {
151                 rxrpc_security_put(conn->security);
152                 conn->security = NULL;
153                 return ret;
154         }
155
156         _leave(" = 0");
157         return 0;
158 }
159
160 /*
161  * initialise the security on a server connection
162  */
163 int rxrpc_init_server_conn_security(struct rxrpc_connection *conn)
164 {
165         struct rxrpc_security *sec;
166         struct rxrpc_local *local = conn->trans->local;
167         struct rxrpc_sock *rx;
168         struct key *key;
169         key_ref_t kref;
170         char kdesc[5+1+3+1];
171
172         _enter("");
173
174         sprintf(kdesc, "%u:%u", ntohs(conn->service_id), conn->security_ix);
175
176         sec = rxrpc_security_lookup(conn->security_ix);
177         if (!sec) {
178                 _leave(" = -ENOKEY [lookup]");
179                 return -ENOKEY;
180         }
181
182         /* find the service */
183         read_lock_bh(&local->services_lock);
184         list_for_each_entry(rx, &local->services, listen_link) {
185                 if (rx->service_id == conn->service_id)
186                         goto found_service;
187         }
188
189         /* the service appears to have died */
190         read_unlock_bh(&local->services_lock);
191         rxrpc_security_put(sec);
192         _leave(" = -ENOENT");
193         return -ENOENT;
194
195 found_service:
196         if (!rx->securities) {
197                 read_unlock_bh(&local->services_lock);
198                 rxrpc_security_put(sec);
199                 _leave(" = -ENOKEY");
200                 return -ENOKEY;
201         }
202
203         /* look through the service's keyring */
204         kref = keyring_search(make_key_ref(rx->securities, 1UL),
205                               &key_type_rxrpc_s, kdesc);
206         if (IS_ERR(kref)) {
207                 read_unlock_bh(&local->services_lock);
208                 rxrpc_security_put(sec);
209                 _leave(" = %ld [search]", PTR_ERR(kref));
210                 return PTR_ERR(kref);
211         }
212
213         key = key_ref_to_ptr(kref);
214         read_unlock_bh(&local->services_lock);
215
216         conn->server_key = key;
217         conn->security = sec;
218
219         _leave(" = 0");
220         return 0;
221 }
222
223 /*
224  * secure a packet prior to transmission
225  */
226 int rxrpc_secure_packet(const struct rxrpc_call *call,
227                         struct sk_buff *skb,
228                         size_t data_size,
229                         void *sechdr)
230 {
231         if (call->conn->security)
232                 return call->conn->security->secure_packet(
233                         call, skb, data_size, sechdr);
234         return 0;
235 }
236
237 /*
238  * secure a packet prior to transmission
239  */
240 int rxrpc_verify_packet(const struct rxrpc_call *call, struct sk_buff *skb,
241                         u32 *_abort_code)
242 {
243         if (call->conn->security)
244                 return call->conn->security->verify_packet(
245                         call, skb, _abort_code);
246         return 0;
247 }
248
249 /*
250  * clear connection security
251  */
252 void rxrpc_clear_conn_security(struct rxrpc_connection *conn)
253 {
254         _enter("{%d}", conn->debug_id);
255
256         if (conn->security) {
257                 conn->security->clear(conn);
258                 rxrpc_security_put(conn->security);
259                 conn->security = NULL;
260         }
261
262         key_put(conn->key);
263         key_put(conn->server_key);
264 }