1 /*
2 * libjingle
3 * Copyright 2014 Google Inc.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions are met:
7 *
8 * 1. Redistributions of source code must retain the above copyright notice,
9 * this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright notice,
11 * this list of conditions and the following disclaimer in the documentation
12 * and/or other materials provided with the distribution.
13 * 3. The name of the author may not be used to endorse or promote products
14 * derived from this software without specific prior written permission.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
17 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
18 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
19 * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
20 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
21 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
22 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
23 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
24 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
25 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26 */
27
28 #if defined(HAVE_SRTP) && defined(ENABLE_EXTERNAL_AUTH)
29
30 #include "talk/session/media/externalhmac.h"
31
32 #include <stdlib.h> // For malloc/free.
33
34 #ifdef SRTP_RELATIVE_PATH
35 #include "srtp.h" // NOLINT
36 #else
37 #include "third_party/libsrtp/include/srtp.h"
38 #endif // SRTP_RELATIVE_PATH
39
40 #include "talk/base/logging.h"
41
42 // Begin test case 0 */
43 static const uint8_t kExternalHmacTestCase0Key[20] = {
44 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b,
45 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b,
46 0x0b, 0x0b, 0x0b, 0x0b
47 };
48
49 static const uint8_t kExternalHmacTestCase0Data[8] = {
50 0x48, 0x69, 0x20, 0x54, 0x68, 0x65, 0x72, 0x65 // "Hi There"
51 };
52
53 static const uint8_t kExternalHmacFakeTag[10] = {
54 0xba, 0xdd, 0xba, 0xdd, 0xba, 0xdd, 0xba, 0xdd, 0xba, 0xdd
55 };
56
57 static const auth_test_case_t kExternalHmacTestCase0 = {
58 20, // Octets in key
59 const_cast<uint8_t*>(kExternalHmacTestCase0Key), // Key
60 8, // Octets in data
61 const_cast<uint8_t*>(kExternalHmacTestCase0Data), // Data
62 10, // Octets in tag
63 const_cast<uint8_t*>(kExternalHmacFakeTag), // Tag
64 NULL // Pointer to next
65 // testcase
66 };
67
68 static const char kExternalHmacDescription[] =
69 "external hmac sha-1 authentication";
70
71 // auth_type_t external_hmac is the hmac metaobject
72
73 static const auth_type_t external_hmac = {
74 external_hmac_alloc,
75 external_hmac_dealloc,
76 (auth_init_func) external_hmac_init,
77 (auth_compute_func) external_hmac_compute,
78 (auth_update_func) external_hmac_update,
79 (auth_start_func) external_hmac_start,
80 const_cast<char*>(kExternalHmacDescription),
81 0, // Instance count.
82 const_cast<auth_test_case_t*>(&kExternalHmacTestCase0),
83 NULL, // No debugging module.
84 EXTERNAL_HMAC_SHA1
85 };
86
87
external_hmac_alloc(auth_t ** a,int key_len,int out_len)88 err_status_t external_hmac_alloc(auth_t** a, int key_len, int out_len) {
89 uint8_t* pointer;
90
91 // Check key length - note that we don't support keys larger
92 // than 20 bytes yet
93 if (key_len > 20)
94 return err_status_bad_param;
95
96 // Check output length - should be less than 20 bytes/
97 if (out_len > 20)
98 return err_status_bad_param;
99
100 // Allocate memory for auth and hmac_ctx_t structures.
101 pointer = new uint8_t[(sizeof(external_hmac_ctx_t) + sizeof(auth_t))];
102 if (pointer == NULL)
103 return err_status_alloc_fail;
104
105 // Set pointers
106 *a = (auth_t *)pointer;
107 // |external_hmac| is const and libsrtp expects |type| to be non-const.
108 // const conversion is required. |external_hmac| is constant because we don't
109 // want to increase global count in Chrome.
110 (*a)->type = const_cast<auth_type_t*>(&external_hmac);
111 (*a)->state = pointer + sizeof(auth_t);
112 (*a)->out_len = out_len;
113 (*a)->key_len = key_len;
114 (*a)->prefix_len = 0;
115
116 return err_status_ok;
117 }
118
external_hmac_dealloc(auth_t * a)119 err_status_t external_hmac_dealloc(auth_t* a) {
120 // Zeroize entire state
121 memset((uint8_t *)a, 0, sizeof(external_hmac_ctx_t) + sizeof(auth_t));
122
123 // Free memory
124 delete[] a;
125
126 return err_status_ok;
127 }
128
external_hmac_init(external_hmac_ctx_t * state,const uint8_t * key,int key_len)129 err_status_t external_hmac_init(external_hmac_ctx_t* state,
130 const uint8_t* key,
131 int key_len) {
132 if (key_len > HMAC_KEY_LENGTH)
133 return err_status_bad_param;
134
135 memset(state->key, 0, key_len);
136 memcpy(state->key, key, key_len);
137 state->key_length = key_len;
138 return err_status_ok;
139 }
140
external_hmac_start(external_hmac_ctx_t * state)141 err_status_t external_hmac_start(external_hmac_ctx_t* state) {
142 return err_status_ok;
143 }
144
external_hmac_update(external_hmac_ctx_t * state,const uint8_t * message,int msg_octets)145 err_status_t external_hmac_update(external_hmac_ctx_t* state,
146 const uint8_t* message,
147 int msg_octets) {
148 return err_status_ok;
149 }
150
external_hmac_compute(external_hmac_ctx_t * state,const void * message,int msg_octets,int tag_len,uint8_t * result)151 err_status_t external_hmac_compute(external_hmac_ctx_t* state,
152 const void* message,
153 int msg_octets,
154 int tag_len,
155 uint8_t* result) {
156 memcpy(result, kExternalHmacFakeTag, tag_len);
157 return err_status_ok;
158 }
159
external_crypto_init()160 err_status_t external_crypto_init() {
161 // |external_hmac| is const. const_cast is required as libsrtp expects
162 // non-const.
163 err_status_t status = crypto_kernel_replace_auth_type(
164 const_cast<auth_type_t*>(&external_hmac), EXTERNAL_HMAC_SHA1);
165 if (status) {
166 LOG(LS_ERROR) << "Error in replacing default auth module, error: "
167 << status;
168 return err_status_fail;
169 }
170 return err_status_ok;
171 }
172
173 #endif // defined(HAVE_SRTP) && defined(ENABLE_EXTERNAL_AUTH)
174