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/*
* TLS Hello Request and Client Hello Messages
* (C) 2004-2011 Jack Lloyd
*
* Botan is released under the Simplified BSD License (see license.txt)
*/
#include <botan/internal/tls_messages.h>
#include <botan/internal/tls_reader.h>
#include <botan/internal/tls_session_key.h>
#include <botan/internal/tls_handshake_io.h>
#include <botan/internal/stl_util.h>
#include <chrono>
namespace Botan {
namespace TLS {
enum {
TLS_EMPTY_RENEGOTIATION_INFO_SCSV = 0x00FF,
TLS_FALLBACK_SCSV = 0x5600
};
std::vector<byte> make_hello_random(RandomNumberGenerator& rng,
const Policy& policy)
{
std::vector<byte> buf(32);
rng.randomize(&buf[0], buf.size());
if(policy.include_time_in_hello_random())
{
const u32bit time32 = static_cast<u32bit>(
std::chrono::system_clock::to_time_t(std::chrono::system_clock::now()));
store_be(time32, &buf[0]);
}
return buf;
}
/*
* Create a new Hello Request message
*/
Hello_Request::Hello_Request(Handshake_IO& io)
{
io.send(*this);
}
/*
* Deserialize a Hello Request message
*/
Hello_Request::Hello_Request(const std::vector<byte>& buf)
{
if(buf.size())
throw Decoding_Error("Bad Hello_Request, has non-zero size");
}
/*
* Serialize a Hello Request message
*/
std::vector<byte> Hello_Request::serialize() const
{
return std::vector<byte>();
}
/*
* Create a new Client Hello message
*/
Client_Hello::Client_Hello(Handshake_IO& io,
Handshake_Hash& hash,
Protocol_Version version,
const Policy& policy,
RandomNumberGenerator& rng,
const std::vector<byte>& reneg_info,
bool next_protocol,
const std::string& hostname,
const std::string& srp_identifier) :
m_version(version),
m_random(make_hello_random(rng, policy)),
m_suites(policy.ciphersuite_list(m_version, (srp_identifier != ""))),
m_comp_methods(policy.compression())
{
m_extensions.add(new Renegotiation_Extension(reneg_info));
m_extensions.add(new SRP_Identifier(srp_identifier));
m_extensions.add(new Server_Name_Indicator(hostname));
m_extensions.add(new Session_Ticket());
m_extensions.add(new Supported_Elliptic_Curves(policy.allowed_ecc_curves()));
if(policy.negotiate_heartbeat_support())
m_extensions.add(new Heartbeat_Support_Indicator(true));
if(m_version.supports_negotiable_signature_algorithms())
m_extensions.add(new Signature_Algorithms(policy.allowed_signature_hashes(),
policy.allowed_signature_methods()));
if(m_version.is_datagram_protocol())
m_extensions.add(new SRTP_Protection_Profiles(policy.srtp_profiles()));
if(reneg_info.empty() && next_protocol)
m_extensions.add(new Next_Protocol_Notification());
BOTAN_ASSERT(policy.acceptable_protocol_version(version),
"Our policy accepts the version we are offering");
if(policy.send_fallback_scsv(version))
m_suites.push_back(TLS_FALLBACK_SCSV);
hash.update(io.send(*this));
}
/*
* Create a new Client Hello message (session resumption case)
*/
Client_Hello::Client_Hello(Handshake_IO& io,
Handshake_Hash& hash,
const Policy& policy,
RandomNumberGenerator& rng,
const std::vector<byte>& reneg_info,
const Session& session,
bool next_protocol) :
m_version(session.version()),
m_session_id(session.session_id()),
m_random(make_hello_random(rng, policy)),
m_suites(policy.ciphersuite_list(m_version, (session.srp_identifier() != ""))),
m_comp_methods(policy.compression())
{
if(!value_exists(m_suites, session.ciphersuite_code()))
m_suites.push_back(session.ciphersuite_code());
if(!value_exists(m_comp_methods, session.compression_method()))
m_comp_methods.push_back(session.compression_method());
m_extensions.add(new Renegotiation_Extension(reneg_info));
m_extensions.add(new SRP_Identifier(session.srp_identifier()));
m_extensions.add(new Server_Name_Indicator(session.server_info().hostname()));
m_extensions.add(new Session_Ticket(session.session_ticket()));
m_extensions.add(new Supported_Elliptic_Curves(policy.allowed_ecc_curves()));
if(policy.negotiate_heartbeat_support())
m_extensions.add(new Heartbeat_Support_Indicator(true));
if(session.fragment_size() != 0)
m_extensions.add(new Maximum_Fragment_Length(session.fragment_size()));
if(m_version.supports_negotiable_signature_algorithms())
m_extensions.add(new Signature_Algorithms(policy.allowed_signature_hashes(),
policy.allowed_signature_methods()));
if(reneg_info.empty() && next_protocol)
m_extensions.add(new Next_Protocol_Notification());
hash.update(io.send(*this));
}
void Client_Hello::update_hello_cookie(const Hello_Verify_Request& hello_verify)
{
if(!m_version.is_datagram_protocol())
throw std::runtime_error("Cannot use hello cookie with stream protocol");
m_hello_cookie = hello_verify.cookie();
}
/*
* Serialize a Client Hello message
*/
std::vector<byte> Client_Hello::serialize() const
{
std::vector<byte> buf;
buf.push_back(m_version.major_version());
buf.push_back(m_version.minor_version());
buf += m_random;
append_tls_length_value(buf, m_session_id, 1);
if(m_version.is_datagram_protocol())
append_tls_length_value(buf, m_hello_cookie, 1);
append_tls_length_value(buf, m_suites, 2);
append_tls_length_value(buf, m_comp_methods, 1);
/*
* May not want to send extensions at all in some cases. If so,
* should include SCSV value (if reneg info is empty, if not we are
* renegotiating with a modern server)
*/
buf += m_extensions.serialize();
return buf;
}
/*
* Read a counterparty client hello
*/
Client_Hello::Client_Hello(const std::vector<byte>& buf)
{
if(buf.size() == 0)
throw Decoding_Error("Client_Hello: Packet corrupted");
if(buf.size() < 41)
throw Decoding_Error("Client_Hello: Packet corrupted");
TLS_Data_Reader reader("ClientHello", buf);
const byte major_version = reader.get_byte();
const byte minor_version = reader.get_byte();
m_version = Protocol_Version(major_version, minor_version);
m_random = reader.get_fixed<byte>(32);
if(m_version.is_datagram_protocol())
m_hello_cookie = reader.get_range<byte>(1, 0, 255);
m_session_id = reader.get_range<byte>(1, 0, 32);
m_suites = reader.get_range_vector<u16bit>(2, 1, 32767);
m_comp_methods = reader.get_range_vector<byte>(1, 1, 255);
m_extensions.deserialize(reader);
if(offered_suite(static_cast<u16bit>(TLS_EMPTY_RENEGOTIATION_INFO_SCSV)))
{
if(Renegotiation_Extension* reneg = m_extensions.get<Renegotiation_Extension>())
{
if(!reneg->renegotiation_info().empty())
throw TLS_Exception(Alert::HANDSHAKE_FAILURE,
"Client sent renegotiation SCSV and non-empty extension");
}
else
{
// add fake extension
m_extensions.add(new Renegotiation_Extension());
}
}
}
bool Client_Hello::sent_fallback_scsv() const
{
return offered_suite(static_cast<u16bit>(TLS_FALLBACK_SCSV));
}
/*
* Check if we offered this ciphersuite
*/
bool Client_Hello::offered_suite(u16bit ciphersuite) const
{
for(size_t i = 0; i != m_suites.size(); ++i)
if(m_suites[i] == ciphersuite)
return true;
return false;
}
}
}
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