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