1 /*
2 * auth.c
3 *
4 * some bookkeeping functions for authentication functions
5 *
6 * David A. McGrew
7 * Cisco Systems, Inc.
8 */
9
10 /*
11 *
12 * Copyright (c) 2001-2017, Cisco Systems, Inc.
13 * All rights reserved.
14 *
15 * Redistribution and use in source and binary forms, with or without
16 * modification, are permitted provided that the following conditions
17 * are met:
18 *
19 * Redistributions of source code must retain the above copyright
20 * notice, this list of conditions and the following disclaimer.
21 *
22 * Redistributions in binary form must reproduce the above
23 * copyright notice, this list of conditions and the following
24 * disclaimer in the documentation and/or other materials provided
25 * with the distribution.
26 *
27 * Neither the name of the Cisco Systems, Inc. nor the names of its
28 * contributors may be used to endorse or promote products derived
29 * from this software without specific prior written permission.
30 *
31 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
32 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
33 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
34 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
35 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
36 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
37 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
38 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
39 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
40 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
41 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
42 * OF THE POSSIBILITY OF SUCH DAMAGE.
43 *
44 */
45
46 #ifdef HAVE_CONFIG_H
47 #include <config.h>
48 #endif
49
50 #include "auth.h"
51 #include "err.h" /* for srtp_debug */
52 #include "datatypes.h" /* for octet_string */
53
54 /* the debug module for authentiation */
55
56 srtp_debug_module_t srtp_mod_auth = {
57 0, /* debugging is off by default */
58 "auth func" /* printable name for module */
59 };
60
srtp_auth_get_key_length(const srtp_auth_t * a)61 int srtp_auth_get_key_length(const srtp_auth_t *a)
62 {
63 return a->key_len;
64 }
65
srtp_auth_get_tag_length(const srtp_auth_t * a)66 int srtp_auth_get_tag_length(const srtp_auth_t *a)
67 {
68 return a->out_len;
69 }
70
srtp_auth_get_prefix_length(const srtp_auth_t * a)71 int srtp_auth_get_prefix_length(const srtp_auth_t *a)
72 {
73 return a->prefix_len;
74 }
75
76 /*
77 * srtp_auth_type_test() tests an auth function of type ct against
78 * test cases provided in a list test_data of values of key, data, and tag
79 * that is known to be good
80 */
81
82 /* should be big enough for most occasions */
83 #define SELF_TEST_TAG_BUF_OCTETS 32
84
srtp_auth_type_test(const srtp_auth_type_t * at,const srtp_auth_test_case_t * test_data)85 srtp_err_status_t srtp_auth_type_test(const srtp_auth_type_t *at,
86 const srtp_auth_test_case_t *test_data)
87 {
88 const srtp_auth_test_case_t *test_case = test_data;
89 srtp_auth_t *a;
90 srtp_err_status_t status;
91 uint8_t tag[SELF_TEST_TAG_BUF_OCTETS];
92 int i, case_num = 0;
93
94 debug_print(srtp_mod_auth, "running self-test for auth function %s",
95 at->description);
96
97 /*
98 * check to make sure that we have at least one test case, and
99 * return an error if we don't - we need to be paranoid here
100 */
101 if (test_case == NULL) {
102 return srtp_err_status_cant_check;
103 }
104
105 /* loop over all test cases */
106 while (test_case != NULL) {
107 /* check test case parameters */
108 if (test_case->tag_length_octets > SELF_TEST_TAG_BUF_OCTETS) {
109 return srtp_err_status_bad_param;
110 }
111
112 /* allocate auth */
113 status = srtp_auth_type_alloc(at, &a, test_case->key_length_octets,
114 test_case->tag_length_octets);
115 if (status) {
116 return status;
117 }
118
119 /* initialize auth */
120 status = srtp_auth_init(a, test_case->key);
121 if (status) {
122 srtp_auth_dealloc(a);
123 return status;
124 }
125
126 /* zeroize tag then compute */
127 octet_string_set_to_zero(tag, test_case->tag_length_octets);
128 status = srtp_auth_compute(a, test_case->data,
129 test_case->data_length_octets, tag);
130 if (status) {
131 srtp_auth_dealloc(a);
132 return status;
133 }
134
135 debug_print(srtp_mod_auth, "key: %s",
136 srtp_octet_string_hex_string(test_case->key,
137 test_case->key_length_octets));
138 debug_print(srtp_mod_auth, "data: %s",
139 srtp_octet_string_hex_string(
140 test_case->data, test_case->data_length_octets));
141 debug_print(
142 srtp_mod_auth, "tag computed: %s",
143 srtp_octet_string_hex_string(tag, test_case->tag_length_octets));
144 debug_print(srtp_mod_auth, "tag expected: %s",
145 srtp_octet_string_hex_string(test_case->tag,
146 test_case->tag_length_octets));
147
148 /* check the result */
149 status = srtp_err_status_ok;
150 for (i = 0; i < test_case->tag_length_octets; i++) {
151 if (tag[i] != test_case->tag[i]) {
152 status = srtp_err_status_algo_fail;
153 debug_print(srtp_mod_auth, "test case %d failed", case_num);
154 debug_print(srtp_mod_auth, " (mismatch at octet %d)", i);
155 }
156 }
157 if (status) {
158 srtp_auth_dealloc(a);
159 return srtp_err_status_algo_fail;
160 }
161
162 /* deallocate the auth function */
163 status = srtp_auth_dealloc(a);
164 if (status) {
165 return status;
166 }
167
168 /*
169 * the auth function passed the test case, so move on to the next test
170 * case in the list; if NULL, we'll quit and return an OK
171 */
172 test_case = test_case->next_test_case;
173 ++case_num;
174 }
175
176 return srtp_err_status_ok;
177 }
178
179 /*
180 * srtp_auth_type_self_test(at) performs srtp_auth_type_test on at's internal
181 * list of test data.
182 */
183
srtp_auth_type_self_test(const srtp_auth_type_t * at)184 srtp_err_status_t srtp_auth_type_self_test(const srtp_auth_type_t *at)
185 {
186 return srtp_auth_type_test(at, at->test_data);
187 }
188