1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
|
/*
* anytun
*
* The secure anycast tunneling protocol (satp) defines a protocol used
* for communication between any combination of unicast and anycast
* tunnel endpoints. It has less protocol overhead than IPSec in Tunnel
* mode and allows tunneling of every ETHER TYPE protocol (e.g.
* ethernet, ip, arp ...). satp directly includes cryptography and
* message authentication based on the methodes used by SRTP. It is
* intended to deliver a generic, scaleable and secure solution for
* tunneling and relaying of packets of any protocol.
*
*
* Copyright (C) 2007-2008 Othmar Gsenger, Erwin Nindl,
* Christian Pointner <satp@wirdorange.org>
*
* This file is part of Anytun.
*
* Anytun is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 3 as
* published by the Free Software Foundation.
*
* Anytun is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with anytun. If not, see <http://www.gnu.org/licenses/>.
*/
#include "authAlgo.h"
#include "log.h"
#include "buffer.h"
#include "encryptedPacket.h"
#include <iostream>
#include <cstring>
//****** NullAuthAlgo ******
void NullAuthAlgo::generate(KeyDerivation& kd, EncryptedPacket& packet)
{
}
bool NullAuthAlgo::checkTag(KeyDerivation& kd, EncryptedPacket& packet)
{
return true;
}
#ifndef NO_CRYPT
//****** Sha1AuthAlgo ******
Sha1AuthAlgo::Sha1AuthAlgo(kd_dir_t d) : AuthAlgo(d), key_(DIGEST_LENGTH)
{
#ifndef USE_SSL_CRYPTO
gcry_error_t err = gcry_md_open(&handle_, GCRY_MD_SHA1, GCRY_MD_FLAG_HMAC);
if(err) {
cLog.msg(Log::PRIO_CRIT) << "Sha1AuthAlgo::Sha1AuthAlgo: Failed to open message digest algo";
return;
}
#else
HMAC_CTX_init(&ctx_);
HMAC_Init_ex(&ctx_, NULL, 0, EVP_sha1(), NULL);
#endif
}
Sha1AuthAlgo::~Sha1AuthAlgo()
{
#ifndef USE_SSL_CRYPTO
if(handle_)
gcry_md_close(handle_);
#else
HMAC_CTX_cleanup(&ctx_);
#endif
}
void Sha1AuthAlgo::generate(KeyDerivation& kd, EncryptedPacket& packet)
{
#ifndef USE_SSL_CRYPTO
if(!handle_)
return;
#endif
packet.addAuthTag();
if(!packet.getAuthTagLength())
return;
kd.generate(dir_, LABEL_SATP_MSG_AUTH, packet.getSeqNr(), key_);
#ifndef USE_SSL_CRYPTO
gcry_error_t err = gcry_md_setkey(handle_, key_.getBuf(), key_.getLength());
if(err) {
cLog.msg(Log::PRIO_ERR) << "Sha1AuthAlgo::setKey: Failed to set hmac key: " << LogGpgError(err);
return;
}
gcry_md_reset(handle_);
gcry_md_write(handle_, packet.getAuthenticatedPortion(), packet.getAuthenticatedPortionLength());
gcry_md_final(handle_);
u_int8_t* hmac = gcry_md_read(handle_, 0);
#else
HMAC_Init_ex(&ctx_, key_.getBuf(), key_.getLength(), EVP_sha1(), NULL);
u_int8_t hmac[DIGEST_LENGTH];
HMAC_Update(&ctx_, packet.getAuthenticatedPortion(), packet.getAuthenticatedPortionLength());
HMAC_Final(&ctx_, hmac, NULL);
#endif
u_int8_t* tag = packet.getAuthTag();
u_int32_t length = (packet.getAuthTagLength() < DIGEST_LENGTH) ? packet.getAuthTagLength() : DIGEST_LENGTH;
if(length > DIGEST_LENGTH)
std::memset(tag, 0, packet.getAuthTagLength());
std::memcpy(&tag[packet.getAuthTagLength() - length], &hmac[DIGEST_LENGTH - length], length);
}
bool Sha1AuthAlgo::checkTag(KeyDerivation& kd, EncryptedPacket& packet)
{
#ifndef USE_SSL_CRYPTO
if(!handle_)
return false;
#endif
packet.withAuthTag(true);
if(!packet.getAuthTagLength())
return true;
kd.generate(dir_, LABEL_SATP_MSG_AUTH, packet.getSeqNr(), key_);
#ifndef USE_SSL_CRYPTO
gcry_error_t err = gcry_md_setkey(handle_, key_.getBuf(), key_.getLength());
if(err) {
cLog.msg(Log::PRIO_ERR) << "Sha1AuthAlgo::setKey: Failed to set hmac key: " << LogGpgError(err);
return false;
}
gcry_md_reset(handle_);
gcry_md_write(handle_, packet.getAuthenticatedPortion(), packet.getAuthenticatedPortionLength());
gcry_md_final(handle_);
u_int8_t* hmac = gcry_md_read(handle_, 0);
#else
HMAC_Init_ex(&ctx_, key_.getBuf(), key_.getLength(), EVP_sha1(), NULL);
u_int8_t hmac[DIGEST_LENGTH];
HMAC_Update(&ctx_, packet.getAuthenticatedPortion(), packet.getAuthenticatedPortionLength());
HMAC_Final(&ctx_, hmac, NULL);
#endif
u_int8_t* tag = packet.getAuthTag();
u_int32_t length = (packet.getAuthTagLength() < DIGEST_LENGTH) ? packet.getAuthTagLength() : DIGEST_LENGTH;
if(length > DIGEST_LENGTH)
for(u_int32_t i=0; i < (packet.getAuthTagLength() - DIGEST_LENGTH); ++i)
if(tag[i]) return false;
int ret = std::memcmp(&tag[packet.getAuthTagLength() - length], &hmac[DIGEST_LENGTH - length], length);
packet.removeAuthTag();
if(ret)
return false;
return true;
}
#endif
|
