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
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
|
/*
* TLS Session State
* (C) 2011-2012,2015 Jack Lloyd
*
* Botan is released under the Simplified BSD License (see license.txt)
*/
#include <botan/tls_session.h>
#include <botan/der_enc.h>
#include <botan/ber_dec.h>
#include <botan/asn1_str.h>
#include <botan/pem.h>
#include <botan/aead.h>
#include <botan/mac.h>
namespace Botan {
namespace TLS {
Session::Session(const std::vector<byte>& session_identifier,
const secure_vector<byte>& master_secret,
Protocol_Version version,
u16bit ciphersuite,
byte compression_method,
Connection_Side side,
bool extended_master_secret,
bool encrypt_then_mac,
const std::vector<X509_Certificate>& certs,
const std::vector<byte>& ticket,
const Server_Information& server_info,
const std::string& srp_identifier,
u16bit srtp_profile) :
m_start_time(std::chrono::system_clock::now()),
m_identifier(session_identifier),
m_session_ticket(ticket),
m_master_secret(master_secret),
m_version(version),
m_ciphersuite(ciphersuite),
m_compression_method(compression_method),
m_connection_side(side),
m_srtp_profile(srtp_profile),
m_extended_master_secret(extended_master_secret),
m_encrypt_then_mac(encrypt_then_mac),
m_peer_certs(certs),
m_server_info(server_info),
m_srp_identifier(srp_identifier)
{
}
Session::Session(const std::string& pem)
{
secure_vector<byte> der = PEM_Code::decode_check_label(pem, "TLS SESSION");
*this = Session(der.data(), der.size());
}
Session::Session(const byte ber[], size_t ber_len)
{
byte side_code = 0;
ASN1_String server_hostname;
ASN1_String server_service;
size_t server_port;
ASN1_String srp_identifier_str;
byte major_version = 0, minor_version = 0;
std::vector<byte> peer_cert_bits;
size_t start_time = 0;
size_t srtp_profile = 0;
size_t fragment_size = 0;
BER_Decoder(ber, ber_len)
.start_cons(SEQUENCE)
.decode_and_check(static_cast<size_t>(TLS_SESSION_PARAM_STRUCT_VERSION),
"Unknown version in serialized TLS session")
.decode_integer_type(start_time)
.decode_integer_type(major_version)
.decode_integer_type(minor_version)
.decode(m_identifier, OCTET_STRING)
.decode(m_session_ticket, OCTET_STRING)
.decode_integer_type(m_ciphersuite)
.decode_integer_type(m_compression_method)
.decode_integer_type(side_code)
.decode_integer_type(fragment_size)
.decode(m_extended_master_secret)
.decode(m_encrypt_then_mac)
.decode(m_master_secret, OCTET_STRING)
.decode(peer_cert_bits, OCTET_STRING)
.decode(server_hostname)
.decode(server_service)
.decode(server_port)
.decode(srp_identifier_str)
.decode(srtp_profile)
.end_cons()
.verify_end();
/*
Fragment size is not supported anymore, but the field is still
set in the session object.
*/
if(fragment_size != 0)
{
throw Decoding_Error("Serialized TLS session used maximum fragment length which is "
" no longer supported");
}
m_version = Protocol_Version(major_version, minor_version);
m_start_time = std::chrono::system_clock::from_time_t(start_time);
m_connection_side = static_cast<Connection_Side>(side_code);
m_srtp_profile = srtp_profile;
m_server_info = Server_Information(server_hostname.value(),
server_service.value(),
server_port);
m_srp_identifier = srp_identifier_str.value();
if(!peer_cert_bits.empty())
{
DataSource_Memory certs(peer_cert_bits.data(), peer_cert_bits.size());
while(!certs.end_of_data())
m_peer_certs.push_back(X509_Certificate(certs));
}
}
secure_vector<byte> Session::DER_encode() const
{
std::vector<byte> peer_cert_bits;
for(size_t i = 0; i != m_peer_certs.size(); ++i)
peer_cert_bits += m_peer_certs[i].BER_encode();
return DER_Encoder()
.start_cons(SEQUENCE)
.encode(static_cast<size_t>(TLS_SESSION_PARAM_STRUCT_VERSION))
.encode(static_cast<size_t>(std::chrono::system_clock::to_time_t(m_start_time)))
.encode(static_cast<size_t>(m_version.major_version()))
.encode(static_cast<size_t>(m_version.minor_version()))
.encode(m_identifier, OCTET_STRING)
.encode(m_session_ticket, OCTET_STRING)
.encode(static_cast<size_t>(m_ciphersuite))
.encode(static_cast<size_t>(m_compression_method))
.encode(static_cast<size_t>(m_connection_side))
.encode(static_cast<size_t>(/*old fragment size*/0))
.encode(m_extended_master_secret)
.encode(m_encrypt_then_mac)
.encode(m_master_secret, OCTET_STRING)
.encode(peer_cert_bits, OCTET_STRING)
.encode(ASN1_String(m_server_info.hostname(), UTF8_STRING))
.encode(ASN1_String(m_server_info.service(), UTF8_STRING))
.encode(static_cast<size_t>(m_server_info.port()))
.encode(ASN1_String(m_srp_identifier, UTF8_STRING))
.encode(static_cast<size_t>(m_srtp_profile))
.end_cons()
.get_contents();
}
std::string Session::PEM_encode() const
{
return PEM_Code::encode(this->DER_encode(), "TLS SESSION");
}
std::chrono::seconds Session::session_age() const
{
return std::chrono::duration_cast<std::chrono::seconds>(
std::chrono::system_clock::now() - m_start_time);
}
std::vector<byte>
Session::encrypt(const SymmetricKey& key, RandomNumberGenerator& rng) const
{
std::unique_ptr<AEAD_Mode> aead(get_aead("AES-256/GCM", ENCRYPTION));
const size_t nonce_len = aead->default_nonce_length();
const secure_vector<byte> nonce = rng.random_vec(nonce_len);
const secure_vector<byte> bits = this->DER_encode();
// Support any length key for input
std::unique_ptr<MessageAuthenticationCode> hmac(MessageAuthenticationCode::create("HMAC(SHA-256)"));
hmac->set_key(key);
hmac->update(nonce);
aead->set_key(hmac->final());
secure_vector<byte> buf = nonce;
buf += bits;
aead->start(buf.data(), nonce_len);
aead->finish(buf, nonce_len);
return unlock(buf);
}
Session Session::decrypt(const byte in[], size_t in_len, const SymmetricKey& key)
{
try
{
std::unique_ptr<AEAD_Mode> aead(get_aead("AES-256/GCM", DECRYPTION));
const size_t nonce_len = aead->default_nonce_length();
if(in_len < nonce_len + aead->tag_size())
throw Decoding_Error("Encrypted session too short to be valid");
// Support any length key for input
std::unique_ptr<MessageAuthenticationCode> hmac(MessageAuthenticationCode::create("HMAC(SHA-256)"));
hmac->set_key(key);
hmac->update(in, nonce_len); // nonce bytes
aead->set_key(hmac->final());
aead->start(in, nonce_len);
secure_vector<byte> buf(in + nonce_len, in + in_len);
aead->finish(buf, 0);
return Session(buf.data(), buf.size());
}
catch(std::exception& e)
{
throw Decoding_Error("Failed to decrypt serialized TLS session: " +
std::string(e.what()));
}
}
}
}
|
