Botan  2.1.0
Crypto and TLS for C++11
tls_session.cpp
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1 /*
2 * TLS Session State
3 * (C) 2011-2012,2015 Jack Lloyd
4 *
5 * Botan is released under the Simplified BSD License (see license.txt)
6 */
7 
8 #include <botan/tls_session.h>
9 #include <botan/der_enc.h>
10 #include <botan/ber_dec.h>
11 #include <botan/asn1_str.h>
12 #include <botan/pem.h>
13 #include <botan/aead.h>
14 #include <botan/mac.h>
15 
16 namespace Botan {
17 
18 namespace TLS {
19 
20 Session::Session(const std::vector<uint8_t>& session_identifier,
21  const secure_vector<uint8_t>& master_secret,
22  Protocol_Version version,
23  uint16_t ciphersuite,
24  uint8_t compression_method,
25  Connection_Side side,
26  bool extended_master_secret,
27  bool encrypt_then_mac,
28  const std::vector<X509_Certificate>& certs,
29  const std::vector<uint8_t>& ticket,
30  const Server_Information& server_info,
31  const std::string& srp_identifier,
32  uint16_t srtp_profile) :
33  m_start_time(std::chrono::system_clock::now()),
34  m_identifier(session_identifier),
35  m_session_ticket(ticket),
36  m_master_secret(master_secret),
37  m_version(version),
38  m_ciphersuite(ciphersuite),
39  m_compression_method(compression_method),
40  m_connection_side(side),
41  m_srtp_profile(srtp_profile),
42  m_extended_master_secret(extended_master_secret),
43  m_encrypt_then_mac(encrypt_then_mac),
44  m_peer_certs(certs),
45  m_server_info(server_info),
46  m_srp_identifier(srp_identifier)
47  {
48  }
49 
50 Session::Session(const std::string& pem)
51  {
52  secure_vector<uint8_t> der = PEM_Code::decode_check_label(pem, "TLS SESSION");
53 
54  *this = Session(der.data(), der.size());
55  }
56 
57 Session::Session(const uint8_t ber[], size_t ber_len)
58  {
59  uint8_t side_code = 0;
60 
61  ASN1_String server_hostname;
62  ASN1_String server_service;
63  size_t server_port;
64 
65  ASN1_String srp_identifier_str;
66 
67  uint8_t major_version = 0, minor_version = 0;
68  std::vector<uint8_t> peer_cert_bits;
69 
70  size_t start_time = 0;
71  size_t srtp_profile = 0;
72  size_t fragment_size = 0;
73 
74  BER_Decoder(ber, ber_len)
76  .decode_and_check(static_cast<size_t>(TLS_SESSION_PARAM_STRUCT_VERSION),
77  "Unknown version in serialized TLS session")
78  .decode_integer_type(start_time)
79  .decode_integer_type(major_version)
80  .decode_integer_type(minor_version)
81  .decode(m_identifier, OCTET_STRING)
82  .decode(m_session_ticket, OCTET_STRING)
83  .decode_integer_type(m_ciphersuite)
84  .decode_integer_type(m_compression_method)
85  .decode_integer_type(side_code)
86  .decode_integer_type(fragment_size)
87  .decode(m_extended_master_secret)
88  .decode(m_encrypt_then_mac)
89  .decode(m_master_secret, OCTET_STRING)
90  .decode(peer_cert_bits, OCTET_STRING)
91  .decode(server_hostname)
92  .decode(server_service)
93  .decode(server_port)
94  .decode(srp_identifier_str)
95  .decode(srtp_profile)
96  .end_cons()
97  .verify_end();
98 
99  /*
100  Fragment size is not supported anymore, but the field is still
101  set in the session object.
102  */
103  if(fragment_size != 0)
104  {
105  throw Decoding_Error("Serialized TLS session used maximum fragment length which is "
106  " no longer supported");
107  }
108 
109  m_version = Protocol_Version(major_version, minor_version);
110  m_start_time = std::chrono::system_clock::from_time_t(start_time);
111  m_connection_side = static_cast<Connection_Side>(side_code);
112  m_srtp_profile = static_cast<uint16_t>(srtp_profile);
113 
114  m_server_info = Server_Information(server_hostname.value(),
115  server_service.value(),
116  static_cast<uint16_t>(server_port));
117 
118  m_srp_identifier = srp_identifier_str.value();
119 
120  if(!peer_cert_bits.empty())
121  {
122  DataSource_Memory certs(peer_cert_bits.data(), peer_cert_bits.size());
123 
124  while(!certs.end_of_data())
125  m_peer_certs.push_back(X509_Certificate(certs));
126  }
127  }
128 
130  {
131  std::vector<uint8_t> peer_cert_bits;
132  for(size_t i = 0; i != m_peer_certs.size(); ++i)
133  peer_cert_bits += m_peer_certs[i].BER_encode();
134 
135  return DER_Encoder()
137  .encode(static_cast<size_t>(TLS_SESSION_PARAM_STRUCT_VERSION))
138  .encode(static_cast<size_t>(std::chrono::system_clock::to_time_t(m_start_time)))
139  .encode(static_cast<size_t>(m_version.major_version()))
140  .encode(static_cast<size_t>(m_version.minor_version()))
141  .encode(m_identifier, OCTET_STRING)
142  .encode(m_session_ticket, OCTET_STRING)
143  .encode(static_cast<size_t>(m_ciphersuite))
144  .encode(static_cast<size_t>(m_compression_method))
145  .encode(static_cast<size_t>(m_connection_side))
146  .encode(static_cast<size_t>(/*old fragment size*/0))
147  .encode(m_extended_master_secret)
148  .encode(m_encrypt_then_mac)
149  .encode(m_master_secret, OCTET_STRING)
150  .encode(peer_cert_bits, OCTET_STRING)
151  .encode(ASN1_String(m_server_info.hostname(), UTF8_STRING))
152  .encode(ASN1_String(m_server_info.service(), UTF8_STRING))
153  .encode(static_cast<size_t>(m_server_info.port()))
154  .encode(ASN1_String(m_srp_identifier, UTF8_STRING))
155  .encode(static_cast<size_t>(m_srtp_profile))
156  .end_cons()
157  .get_contents();
158  }
159 
160 std::string Session::PEM_encode() const
161  {
162  return PEM_Code::encode(this->DER_encode(), "TLS SESSION");
163  }
164 
165 std::chrono::seconds Session::session_age() const
166  {
167  return std::chrono::duration_cast<std::chrono::seconds>(
168  std::chrono::system_clock::now() - m_start_time);
169  }
170 
171 std::vector<uint8_t>
173  {
174  std::unique_ptr<AEAD_Mode> aead(get_aead("AES-256/GCM", ENCRYPTION));
175  const size_t nonce_len = aead->default_nonce_length();
176 
177  const secure_vector<uint8_t> nonce = rng.random_vec(nonce_len);
178  const secure_vector<uint8_t> bits = this->DER_encode();
179 
180  // Support any length key for input
181  std::unique_ptr<MessageAuthenticationCode> hmac(MessageAuthenticationCode::create("HMAC(SHA-256)"));
182  hmac->set_key(key);
183  hmac->update(nonce);
184  aead->set_key(hmac->final());
185 
186  secure_vector<uint8_t> buf = nonce;
187  buf += bits;
188  aead->start(buf.data(), nonce_len);
189  aead->finish(buf, nonce_len);
190  return unlock(buf);
191  }
192 
193 Session Session::decrypt(const uint8_t in[], size_t in_len, const SymmetricKey& key)
194  {
195  try
196  {
197  std::unique_ptr<AEAD_Mode> aead(get_aead("AES-256/GCM", DECRYPTION));
198  const size_t nonce_len = aead->default_nonce_length();
199 
200  if(in_len < nonce_len + aead->tag_size())
201  throw Decoding_Error("Encrypted session too short to be valid");
202 
203  // Support any length key for input
204  std::unique_ptr<MessageAuthenticationCode> hmac(MessageAuthenticationCode::create("HMAC(SHA-256)"));
205  hmac->set_key(key);
206  hmac->update(in, nonce_len); // nonce bytes
207  aead->set_key(hmac->final());
208 
209  aead->start(in, nonce_len);
210  secure_vector<uint8_t> buf(in + nonce_len, in + in_len);
211  aead->finish(buf, 0);
212 
213  return Session(buf.data(), buf.size());
214  }
215  catch(std::exception& e)
216  {
217  throw Decoding_Error("Failed to decrypt serialized TLS session: " +
218  std::string(e.what()));
219  }
220  }
221 
222 }
223 
224 }
uint8_t minor_version() const
Definition: tls_version.h:82
static Session decrypt(const uint8_t ctext[], size_t ctext_size, const SymmetricKey &key)
std::chrono::system_clock::time_point start_time() const
Definition: tls_session.h:175
std::string value() const
Definition: asn1_str.cpp:99
static std::unique_ptr< MessageAuthenticationCode > create(const std::string &algo_spec, const std::string &provider="")
Definition: mac.cpp:43
secure_vector< uint8_t > random_vec(size_t bytes)
Definition: rng.h:133
BER_Decoder & decode_integer_type(T &out)
Definition: ber_dec.h:111
std::string service() const
secure_vector< uint8_t > DER_encode() const
std::string encode(const uint8_t der[], size_t length, const std::string &label, size_t width)
Definition: pem.cpp:43
BER_Decoder & decode_and_check(const T &expected, const std::string &error_msg)
Definition: ber_dec.h:146
secure_vector< uint8_t > BER_encode(const Private_Key &key)
Definition: pkcs8.cpp:130
secure_vector< uint8_t > get_contents()
Definition: der_enc.cpp:124
Definition: bigint.h:619
std::vector< uint8_t > encrypt(const SymmetricKey &key, RandomNumberGenerator &rng) const
BER_Decoder & decode(bool &v)
Definition: ber_dec.cpp:376
DER_Encoder & end_cons()
Definition: der_enc.cpp:147
std::string hostname() const
DER_Encoder & encode(bool b)
Definition: der_enc.cpp:216
std::vector< T, secure_allocator< T >> secure_vector
Definition: secmem.h:121
BER_Decoder & end_cons()
Definition: ber_dec.cpp:272
uint8_t major_version() const
Definition: tls_version.h:77
AEAD_Mode * get_aead(const std::string &algo, Cipher_Dir dir)
Definition: aead.cpp:41
BER_Decoder start_cons(ASN1_Tag type_tag, ASN1_Tag class_tag=UNIVERSAL)
Definition: ber_dec.cpp:258
Definition: alg_id.cpp:13
std::chrono::seconds session_age() const
std::vector< T > unlock(const secure_vector< T > &in)
Definition: secmem.h:125
secure_vector< uint8_t > decode_check_label(DataSource &source, const std::string &label_want)
Definition: pem.cpp:54
BER_Decoder & verify_end()
Definition: ber_dec.cpp:168
DER_Encoder & start_cons(ASN1_Tag type_tag, ASN1_Tag class_tag=UNIVERSAL)
Definition: der_enc.cpp:137
std::string PEM_encode() const