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
167
168
169
170
171
172
173
174
175
176
177
178
179
|
/*
* Server Key Exchange Message
* (C) 2004-2010 Jack Lloyd
*
* Released under the terms of the Botan license
*/
#include <botan/internal/tls_messages.h>
#include <botan/internal/tls_reader.h>
#include <botan/pubkey.h>
#include <botan/dh.h>
#include <botan/rsa.h>
#include <botan/dsa.h>
#include <botan/loadstor.h>
#include <memory>
namespace Botan {
/**
* Create a new Server Key Exchange message
*/
Server_Key_Exchange::Server_Key_Exchange(RandomNumberGenerator& rng,
Record_Writer& writer,
const Public_Key* kex_key,
const Private_Key* priv_key,
const MemoryRegion<byte>& c_random,
const MemoryRegion<byte>& s_random,
HandshakeHash& hash)
{
const DH_PublicKey* dh_pub = dynamic_cast<const DH_PublicKey*>(kex_key);
const RSA_PublicKey* rsa_pub = dynamic_cast<const RSA_PublicKey*>(kex_key);
if(dh_pub)
{
params.push_back(dh_pub->get_domain().get_p());
params.push_back(dh_pub->get_domain().get_g());
params.push_back(BigInt::decode(dh_pub->public_value()));
}
else if(rsa_pub)
{
params.push_back(rsa_pub->get_n());
params.push_back(rsa_pub->get_e());
}
else
throw Invalid_Argument("Bad key for TLS key exchange: not DH or RSA");
std::string padding = "";
Signature_Format format = IEEE_1363;
if(priv_key->algo_name() == "RSA")
padding = "EMSA3(TLS.Digest.0)";
else if(priv_key->algo_name() == "DSA")
{
padding = "EMSA1(SHA-1)";
format = DER_SEQUENCE;
}
else
throw Invalid_Argument(priv_key->algo_name() +
" is invalid/unknown for TLS signatures");
PK_Signer signer(*priv_key, padding, format);
signer.update(c_random);
signer.update(s_random);
signer.update(serialize_params());
signature = signer.signature(rng);
send(writer, hash);
}
/**
* Serialize a Server Key Exchange message
*/
SecureVector<byte> Server_Key_Exchange::serialize() const
{
SecureVector<byte> buf = serialize_params();
append_tls_length_value(buf, signature, 2);
return buf;
}
/**
* Serialize the ServerParams structure
*/
SecureVector<byte> Server_Key_Exchange::serialize_params() const
{
SecureVector<byte> buf;
for(u32bit j = 0; j != params.size(); j++)
append_tls_length_value(buf, BigInt::encode(params[j]), 2);
return buf;
}
/**
* Deserialize a Server Key Exchange message
*/
void Server_Key_Exchange::deserialize(const MemoryRegion<byte>& buf)
{
if(buf.size() < 6)
throw Decoding_Error("Server_Key_Exchange: Packet corrupted");
SecureVector<byte> values[4];
u32bit so_far = 0;
for(u32bit j = 0; j != 4; j++)
{
u16bit len = make_u16bit(buf[so_far], buf[so_far+1]);
so_far += 2;
if(len + so_far > buf.size())
throw Decoding_Error("Server_Key_Exchange: Packet corrupted");
values[j].set(&buf[so_far], len);
so_far += len;
if(j == 2 && so_far == buf.size())
break;
}
params.push_back(BigInt::decode(values[0]));
params.push_back(BigInt::decode(values[1]));
if(values[3].size())
{
params.push_back(BigInt::decode(values[2]));
signature = values[3];
}
else
signature = values[2];
}
/**
* Return the public key
*/
Public_Key* Server_Key_Exchange::key() const
{
if(params.size() == 2)
return new RSA_PublicKey(params[0], params[1]);
else if(params.size() == 3)
return new DH_PublicKey(DL_Group(params[0], params[1]), params[2]);
else
throw Internal_Error("Server_Key_Exchange::key: No key set");
}
/**
* Verify a Server Key Exchange message
*/
bool Server_Key_Exchange::verify(const X509_Certificate& cert,
const MemoryRegion<byte>& c_random,
const MemoryRegion<byte>& s_random) const
{
std::auto_ptr<Public_Key> key(cert.subject_public_key());
std::string padding = "";
Signature_Format format = IEEE_1363;
if(key->algo_name() == "RSA")
padding = "EMSA3(TLS.Digest.0)";
else if(key->algo_name() == "DSA")
{
padding == "EMSA1(SHA-1)";
format = DER_SEQUENCE;
}
else
throw Invalid_Argument(key->algo_name() +
" is invalid/unknown for TLS signatures");
PK_Verifier verifier(*key, padding, format);
SecureVector<byte> params_got = serialize_params();
verifier.update(c_random);
verifier.update(s_random);
verifier.update(params_got);
return verifier.check_signature(signature);
}
}
|
