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/*
* TLS Handshaking
* (C) 2004-2006,2011 Jack Lloyd
*
* Released under the terms of the Botan license
*/
#include <botan/internal/tls_handshake_state.h>
#include <botan/internal/tls_messages.h>
#include <botan/internal/assert.h>
#include <botan/lookup.h>
namespace Botan {
namespace TLS {
namespace {
u32bit bitmask_for_handshake_type(Handshake_Type type)
{
switch(type)
{
case HELLO_VERIFY_REQUEST:
return (1 << 0);
case HELLO_REQUEST:
return (1 << 1);
/*
* Same code point for both client hello styles
*/
case CLIENT_HELLO:
case CLIENT_HELLO_SSLV2:
return (1 << 2);
case SERVER_HELLO:
return (1 << 3);
case CERTIFICATE:
return (1 << 4);
case CERTIFICATE_URL:
return (1 << 5);
case CERTIFICATE_STATUS:
return (1 << 6);
case SERVER_KEX:
return (1 << 7);
case CERTIFICATE_REQUEST:
return (1 << 8);
case SERVER_HELLO_DONE:
return (1 << 9);
case CERTIFICATE_VERIFY:
return (1 << 10);
case CLIENT_KEX:
return (1 << 11);
case NEXT_PROTOCOL:
return (1 << 12);
case NEW_SESSION_TICKET:
return (1 << 13);
case HANDSHAKE_CCS:
return (1 << 14);
case FINISHED:
return (1 << 15);
// allow explicitly disabling new handshakes
case HANDSHAKE_NONE:
return 0;
}
throw Internal_Error("Unknown handshake type " + std::to_string(type));
}
}
/*
* Initialize the SSL/TLS Handshake State
*/
Handshake_State::Handshake_State(Handshake_Reader* reader,
Handshake_Writer* writer) :
m_handshake_reader(reader),
m_handshake_writer(writer),
m_version(Protocol_Version::SSL_V3)
{
}
void Handshake_State::set_version(const Protocol_Version& version)
{
m_version = version;
}
void Handshake_State::confirm_transition_to(Handshake_Type handshake_msg)
{
const u32bit mask = bitmask_for_handshake_type(handshake_msg);
m_hand_received_mask |= mask;
const bool ok = (m_hand_expecting_mask & mask); // overlap?
if(!ok)
throw Unexpected_Message("Unexpected state transition in handshake, got " +
std::to_string(handshake_msg) +
" expected " + std::to_string(m_hand_expecting_mask) +
" received " + std::to_string(m_hand_received_mask));
/* We don't know what to expect next, so force a call to
set_expected_next; if it doesn't happen, the next transition
check will always fail which is what we want.
*/
m_hand_expecting_mask = 0;
}
void Handshake_State::set_expected_next(Handshake_Type handshake_msg)
{
m_hand_expecting_mask |= bitmask_for_handshake_type(handshake_msg);
}
bool Handshake_State::received_handshake_msg(Handshake_Type handshake_msg) const
{
const u32bit mask = bitmask_for_handshake_type(handshake_msg);
return (m_hand_received_mask & mask);
}
std::string Handshake_State::srp_identifier() const
{
if(suite.valid() && suite.kex_algo() == "SRP_SHA")
return client_hello->srp_identifier();
return "";
}
const std::vector<byte>& Handshake_State::session_ticket() const
{
if(new_session_ticket && !new_session_ticket->ticket().empty())
return new_session_ticket->ticket();
return client_hello->session_ticket();
}
KDF* Handshake_State::protocol_specific_prf()
{
if(version() == Protocol_Version::SSL_V3)
{
return get_kdf("SSL3-PRF");
}
else if(version() == Protocol_Version::TLS_V10 || version() == Protocol_Version::TLS_V11)
{
return get_kdf("TLS-PRF");
}
else if(version() == Protocol_Version::TLS_V12)
{
if(suite.mac_algo() == "MD5" ||
suite.mac_algo() == "SHA-1" ||
suite.mac_algo() == "SHA-256")
{
return get_kdf("TLS-12-PRF(SHA-256)");
}
return get_kdf("TLS-12-PRF(" + suite.mac_algo() + ")");
}
throw Internal_Error("Unknown version code " + version().to_string());
}
namespace {
std::string choose_hash(const std::string& sig_algo,
Protocol_Version negotiated_version,
const Policy& policy,
bool for_client_auth,
Client_Hello* client_hello,
Certificate_Req* cert_req)
{
if(!negotiated_version.supports_negotiable_signature_algorithms())
{
if(for_client_auth && negotiated_version == Protocol_Version::SSL_V3)
return "Raw";
if(sig_algo == "RSA")
return "TLS.Digest.0";
if(sig_algo == "DSA")
return "SHA-1";
if(sig_algo == "ECDSA")
return "SHA-1";
throw Internal_Error("Unknown TLS signature algo " + sig_algo);
}
const auto supported_algos = for_client_auth ?
cert_req->supported_algos() :
client_hello->supported_algos();
if(!supported_algos.empty())
{
const auto hashes = policy.allowed_signature_hashes();
/*
* Choose our most preferred hash that the counterparty supports
* in pairing with the signature algorithm we want to use.
*/
for(auto hash : hashes)
{
for(auto algo : supported_algos)
{
if(algo.first == hash && algo.second == sig_algo)
return hash;
}
}
}
// TLS v1.2 default hash if the counterparty sent nothing
return "SHA-1";
}
}
std::pair<std::string, Signature_Format>
Handshake_State::choose_sig_format(const Private_Key* key,
std::string& hash_algo_out,
std::string& sig_algo_out,
bool for_client_auth,
const Policy& policy)
{
const std::string sig_algo = key->algo_name();
const std::string hash_algo =
choose_hash(sig_algo,
this->version(),
policy,
for_client_auth,
client_hello,
cert_req);
if(this->version().supports_negotiable_signature_algorithms())
{
hash_algo_out = hash_algo;
sig_algo_out = sig_algo;
}
if(sig_algo == "RSA")
{
const std::string padding = "EMSA3(" + hash_algo + ")";
return std::make_pair(padding, IEEE_1363);
}
else if(sig_algo == "DSA" || sig_algo == "ECDSA")
{
const std::string padding = "EMSA1(" + hash_algo + ")";
return std::make_pair(padding, DER_SEQUENCE);
}
throw Invalid_Argument(sig_algo + " is invalid/unknown for TLS signatures");
}
std::pair<std::string, Signature_Format>
Handshake_State::understand_sig_format(const Public_Key* key,
std::string hash_algo,
std::string sig_algo,
bool for_client_auth)
{
const std::string algo_name = key->algo_name();
/*
FIXME: This should check what was sent against the client hello
preferences, or the certificate request, to ensure it was allowed
by those restrictions.
Or not?
*/
if(this->version().supports_negotiable_signature_algorithms())
{
if(hash_algo == "")
throw Decoding_Error("Counterparty did not send hash/sig IDS");
if(sig_algo != algo_name)
throw Decoding_Error("Counterparty sent inconsistent key and sig types");
}
else
{
if(hash_algo != "" || sig_algo != "")
throw Decoding_Error("Counterparty sent hash/sig IDs with old version");
}
if(algo_name == "RSA")
{
if(for_client_auth && this->version() == Protocol_Version::SSL_V3)
{
hash_algo = "Raw";
}
else if(!this->version().supports_negotiable_signature_algorithms())
{
hash_algo = "TLS.Digest.0";
}
const std::string padding = "EMSA3(" + hash_algo + ")";
return std::make_pair(padding, IEEE_1363);
}
else if(algo_name == "DSA" || algo_name == "ECDSA")
{
if(algo_name == "DSA" && for_client_auth && this->version() == Protocol_Version::SSL_V3)
{
hash_algo = "Raw";
}
else if(!this->version().supports_negotiable_signature_algorithms())
{
hash_algo = "SHA-1";
}
const std::string padding = "EMSA1(" + hash_algo + ")";
return std::make_pair(padding, DER_SEQUENCE);
}
throw Invalid_Argument(algo_name + " is invalid/unknown for TLS signatures");
}
/*
* Destroy the SSL/TLS Handshake State
*/
Handshake_State::~Handshake_State()
{
delete client_hello;
delete server_hello;
delete server_certs;
delete server_kex;
delete cert_req;
delete server_hello_done;
delete next_protocol;
delete new_session_ticket;
delete client_certs;
delete client_kex;
delete client_verify;
delete client_finished;
delete server_finished;
delete m_handshake_reader;
delete m_handshake_writer;
}
}
}
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