1 /*
2 * null_auth.c
3 *
4 * implements the do-nothing auth algorithm
5 *
6 * David A. McGrew
7 * Cisco Systems, Inc.
8 *
9 */
10
11 /*
12 *
13 * Copyright (c) 2001-2017, Cisco Systems, Inc.
14 * All rights reserved.
15 *
16 * Redistribution and use in source and binary forms, with or without
17 * modification, are permitted provided that the following conditions
18 * are met:
19 *
20 * Redistributions of source code must retain the above copyright
21 * notice, this list of conditions and the following disclaimer.
22 *
23 * Redistributions in binary form must reproduce the above
24 * copyright notice, this list of conditions and the following
25 * disclaimer in the documentation and/or other materials provided
26 * with the distribution.
27 *
28 * Neither the name of the Cisco Systems, Inc. nor the names of its
29 * contributors may be used to endorse or promote products derived
30 * from this software without specific prior written permission.
31 *
32 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
33 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
34 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
35 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
36 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
37 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
38 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
39 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
40 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
41 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
42 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
43 * OF THE POSSIBILITY OF SUCH DAMAGE.
44 *
45 */
46
47 #ifdef HAVE_CONFIG_H
48 #include <config.h>
49 #endif
50
51 #include "null_auth.h"
52 #include "err.h" /* for srtp_debug */
53 #include "alloc.h"
54 #include "cipher_types.h"
55
srtp_null_auth_alloc(srtp_auth_t ** a,int key_len,int out_len)56 static srtp_err_status_t srtp_null_auth_alloc(srtp_auth_t **a,
57 int key_len,
58 int out_len)
59 {
60 extern const srtp_auth_type_t srtp_null_auth;
61 uint8_t *pointer;
62
63 debug_print(srtp_mod_auth, "allocating auth func with key length %d",
64 key_len);
65 debug_print(srtp_mod_auth, " tag length %d",
66 out_len);
67
68 /* allocate memory for auth and srtp_null_auth_ctx_t structures */
69 pointer = (uint8_t *)srtp_crypto_alloc(sizeof(srtp_null_auth_ctx_t) +
70 sizeof(srtp_auth_t));
71 if (pointer == NULL) {
72 return srtp_err_status_alloc_fail;
73 }
74
75 /* set pointers */
76 *a = (srtp_auth_t *)pointer;
77 (*a)->type = &srtp_null_auth;
78 (*a)->state = pointer + sizeof(srtp_auth_t);
79 (*a)->out_len = out_len;
80 (*a)->prefix_len = out_len;
81 (*a)->key_len = key_len;
82
83 return srtp_err_status_ok;
84 }
85
srtp_null_auth_dealloc(srtp_auth_t * a)86 static srtp_err_status_t srtp_null_auth_dealloc(srtp_auth_t *a)
87 {
88 extern const srtp_auth_type_t srtp_null_auth;
89
90 /* zeroize entire state*/
91 octet_string_set_to_zero(a, sizeof(srtp_null_auth_ctx_t) +
92 sizeof(srtp_auth_t));
93
94 /* free memory */
95 srtp_crypto_free(a);
96
97 return srtp_err_status_ok;
98 }
99
srtp_null_auth_init(void * statev,const uint8_t * key,int key_len)100 static srtp_err_status_t srtp_null_auth_init(void *statev,
101 const uint8_t *key,
102 int key_len)
103 {
104 /* srtp_null_auth_ctx_t *state = (srtp_null_auth_ctx_t *)statev; */
105 /* accept any length of key, and do nothing */
106
107 return srtp_err_status_ok;
108 }
109
srtp_null_auth_compute(void * statev,const uint8_t * message,int msg_octets,int tag_len,uint8_t * result)110 static srtp_err_status_t srtp_null_auth_compute(void *statev,
111 const uint8_t *message,
112 int msg_octets,
113 int tag_len,
114 uint8_t *result)
115 {
116 /* srtp_null_auth_ctx_t *state = (srtp_null_auth_ctx_t *)statev; */
117
118 return srtp_err_status_ok;
119 }
120
srtp_null_auth_update(void * statev,const uint8_t * message,int msg_octets)121 static srtp_err_status_t srtp_null_auth_update(void *statev,
122 const uint8_t *message,
123 int msg_octets)
124 {
125 /* srtp_null_auth_ctx_t *state = (srtp_null_auth_ctx_t *)statev; */
126
127 return srtp_err_status_ok;
128 }
129
srtp_null_auth_start(void * statev)130 static srtp_err_status_t srtp_null_auth_start(void *statev)
131 {
132 /* srtp_null_auth_ctx_t *state = (srtp_null_auth_ctx_t *)statev; */
133
134 return srtp_err_status_ok;
135 }
136
137 /*
138 * srtp_auth_type_t - defines description, test case, and null_auth
139 * metaobject
140 */
141
142 /* begin test case 0 */
143
144 static const srtp_auth_test_case_t srtp_null_auth_test_case_0 = {
145 0, /* octets in key */
146 NULL, /* key */
147 0, /* octets in data */
148 NULL, /* data */
149 0, /* octets in tag */
150 NULL, /* tag */
151 NULL /* pointer to next testcase */
152 };
153
154 /* end test case 0 */
155
156 static const char srtp_null_auth_description[] = "null authentication function";
157
158 const srtp_auth_type_t srtp_null_auth = {
159 srtp_null_auth_alloc, /* */
160 srtp_null_auth_dealloc, /* */
161 srtp_null_auth_init, /* */
162 srtp_null_auth_compute, /* */
163 srtp_null_auth_update, /* */
164 srtp_null_auth_start, /* */
165 srtp_null_auth_description, /* */
166 &srtp_null_auth_test_case_0, /* */
167 SRTP_NULL_AUTH /* */
168 };
169