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
 22static LIST_HEAD(rxrpc_security_methods);
 23static DECLARE_RWSEM(rxrpc_security_sem);
 24
 25/*
 26 * get an RxRPC security module
 27 */
 28static 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 */
 36static 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 */
 44static 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;
 61out:
 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 */
 73int 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
 93out:
 94	up_write(&rxrpc_security_sem);
 95	_leave(" = %d", ret);
 96	return ret;
 97}
 98
 99EXPORT_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 */
107void 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
119EXPORT_SYMBOL_GPL(rxrpc_unregister_security);
120
121/*
122 * initialise the security on a client connection
123 */
124int 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 */
163int 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
195found_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 */
226int 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 */
240int 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 */
252void 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}