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/*
* 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 = static_cast<u16bit>(srtp_profile);
m_server_info = Server_Information(server_hostname.value(),
server_service.value(),
static_cast<u16bit>(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()));
}
}
}
}
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