xref: /openbmc/linux/net/rxrpc/security.c (revision 2169e6da)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* RxRPC security handling
3  *
4  * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
5  * Written by David Howells (dhowells@redhat.com)
6  */
7 
8 #include <linux/module.h>
9 #include <linux/net.h>
10 #include <linux/skbuff.h>
11 #include <linux/udp.h>
12 #include <linux/crypto.h>
13 #include <net/sock.h>
14 #include <net/af_rxrpc.h>
15 #include <keys/rxrpc-type.h>
16 #include "ar-internal.h"
17 
18 static const struct rxrpc_security *rxrpc_security_types[] = {
19 	[RXRPC_SECURITY_NONE]	= &rxrpc_no_security,
20 #ifdef CONFIG_RXKAD
21 	[RXRPC_SECURITY_RXKAD]	= &rxkad,
22 #endif
23 };
24 
25 int __init rxrpc_init_security(void)
26 {
27 	int i, ret;
28 
29 	for (i = 0; i < ARRAY_SIZE(rxrpc_security_types); i++) {
30 		if (rxrpc_security_types[i]) {
31 			ret = rxrpc_security_types[i]->init();
32 			if (ret < 0)
33 				goto failed;
34 		}
35 	}
36 
37 	return 0;
38 
39 failed:
40 	for (i--; i >= 0; i--)
41 		if (rxrpc_security_types[i])
42 			rxrpc_security_types[i]->exit();
43 	return ret;
44 }
45 
46 void rxrpc_exit_security(void)
47 {
48 	int i;
49 
50 	for (i = 0; i < ARRAY_SIZE(rxrpc_security_types); i++)
51 		if (rxrpc_security_types[i])
52 			rxrpc_security_types[i]->exit();
53 }
54 
55 /*
56  * look up an rxrpc security module
57  */
58 static const struct rxrpc_security *rxrpc_security_lookup(u8 security_index)
59 {
60 	if (security_index >= ARRAY_SIZE(rxrpc_security_types))
61 		return NULL;
62 	return rxrpc_security_types[security_index];
63 }
64 
65 /*
66  * initialise the security on a client connection
67  */
68 int rxrpc_init_client_conn_security(struct rxrpc_connection *conn)
69 {
70 	const struct rxrpc_security *sec;
71 	struct rxrpc_key_token *token;
72 	struct key *key = conn->params.key;
73 	int ret;
74 
75 	_enter("{%d},{%x}", conn->debug_id, key_serial(key));
76 
77 	if (!key)
78 		return 0;
79 
80 	ret = key_validate(key);
81 	if (ret < 0)
82 		return ret;
83 
84 	token = key->payload.data[0];
85 	if (!token)
86 		return -EKEYREJECTED;
87 
88 	sec = rxrpc_security_lookup(token->security_index);
89 	if (!sec)
90 		return -EKEYREJECTED;
91 	conn->security = sec;
92 
93 	ret = conn->security->init_connection_security(conn);
94 	if (ret < 0) {
95 		conn->security = &rxrpc_no_security;
96 		return ret;
97 	}
98 
99 	_leave(" = 0");
100 	return 0;
101 }
102 
103 /*
104  * initialise the security on a server connection
105  */
106 int rxrpc_init_server_conn_security(struct rxrpc_connection *conn)
107 {
108 	const struct rxrpc_security *sec;
109 	struct rxrpc_local *local = conn->params.local;
110 	struct rxrpc_sock *rx;
111 	struct key *key;
112 	key_ref_t kref;
113 	char kdesc[5 + 1 + 3 + 1];
114 
115 	_enter("");
116 
117 	sprintf(kdesc, "%u:%u", conn->service_id, conn->security_ix);
118 
119 	sec = rxrpc_security_lookup(conn->security_ix);
120 	if (!sec) {
121 		_leave(" = -ENOKEY [lookup]");
122 		return -ENOKEY;
123 	}
124 
125 	/* find the service */
126 	read_lock(&local->services_lock);
127 	rx = rcu_dereference_protected(local->service,
128 				       lockdep_is_held(&local->services_lock));
129 	if (rx && (rx->srx.srx_service == conn->service_id ||
130 		   rx->second_service == conn->service_id))
131 		goto found_service;
132 
133 	/* the service appears to have died */
134 	read_unlock(&local->services_lock);
135 	_leave(" = -ENOENT");
136 	return -ENOENT;
137 
138 found_service:
139 	if (!rx->securities) {
140 		read_unlock(&local->services_lock);
141 		_leave(" = -ENOKEY");
142 		return -ENOKEY;
143 	}
144 
145 	/* look through the service's keyring */
146 	kref = keyring_search(make_key_ref(rx->securities, 1UL),
147 			      &key_type_rxrpc_s, kdesc, true);
148 	if (IS_ERR(kref)) {
149 		read_unlock(&local->services_lock);
150 		_leave(" = %ld [search]", PTR_ERR(kref));
151 		return PTR_ERR(kref);
152 	}
153 
154 	key = key_ref_to_ptr(kref);
155 	read_unlock(&local->services_lock);
156 
157 	conn->server_key = key;
158 	conn->security = sec;
159 
160 	_leave(" = 0");
161 	return 0;
162 }
163