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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  */
rxrpc_security_get(struct rxrpc_security * sec)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  */
rxrpc_security_put(struct rxrpc_security * sec)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  */
rxrpc_security_lookup(u8 security_index)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  */
rxrpc_register_security(struct rxrpc_security * sec)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  */
rxrpc_unregister_security(struct rxrpc_security * sec)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  */
rxrpc_init_client_conn_security(struct rxrpc_connection * conn)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 	token = key->payload.data[0];
141 	if (!token)
142 		return -EKEYREJECTED;
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  */
rxrpc_init_server_conn_security(struct rxrpc_connection * conn)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  */
rxrpc_secure_packet(const struct rxrpc_call * call,struct sk_buff * skb,size_t data_size,void * sechdr)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  */
rxrpc_verify_packet(const struct rxrpc_call * call,struct sk_buff * skb,u32 * _abort_code)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  */
rxrpc_clear_conn_security(struct rxrpc_connection * conn)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 }
265