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/*
* Finished Message
* (C) 2004-2006,2012 Jack Lloyd
*
* Released under the terms of the Botan license
*/
#include <botan/internal/tls_messages.h>
#include <botan/prf_tls.h>
#include <botan/hmac.h>
#include <botan/sha2_32.h>
#include <memory>
namespace Botan {
namespace TLS {
namespace {
KDF* choose_tls_prf(Protocol_Version version)
{
if(version == Protocol_Version::TLS_V10 || version == Protocol_Version::TLS_V11)
return new TLS_PRF;
else if(version == Protocol_Version::TLS_V12)
return new TLS_12_PRF(new HMAC(new SHA_256)); // might depend on ciphersuite
else
throw TLS_Exception(PROTOCOL_VERSION,
"Unknown version for PRF");
}
/*
* Compute the verify_data
*/
MemoryVector<byte> finished_compute_verify(Handshake_State* state,
Connection_Side side)
{
if(state->version == Protocol_Version::SSL_V3)
{
const byte SSL_CLIENT_LABEL[] = { 0x43, 0x4C, 0x4E, 0x54 };
const byte SSL_SERVER_LABEL[] = { 0x53, 0x52, 0x56, 0x52 };
Handshake_Hash hash = state->hash; // don't modify state
MemoryVector<byte> ssl3_finished;
if(side == CLIENT)
hash.update(SSL_CLIENT_LABEL, sizeof(SSL_CLIENT_LABEL));
else
hash.update(SSL_SERVER_LABEL, sizeof(SSL_SERVER_LABEL));
return hash.final_ssl3(state->keys.master_secret());
}
else
{
const byte TLS_CLIENT_LABEL[] = {
0x63, 0x6C, 0x69, 0x65, 0x6E, 0x74, 0x20, 0x66, 0x69, 0x6E, 0x69,
0x73, 0x68, 0x65, 0x64 };
const byte TLS_SERVER_LABEL[] = {
0x73, 0x65, 0x72, 0x76, 0x65, 0x72, 0x20, 0x66, 0x69, 0x6E, 0x69,
0x73, 0x68, 0x65, 0x64 };
std::auto_ptr<KDF> prf(choose_tls_prf(state->version));
MemoryVector<byte> input;
if(side == CLIENT)
input += std::make_pair(TLS_CLIENT_LABEL, sizeof(TLS_CLIENT_LABEL));
else
input += std::make_pair(TLS_SERVER_LABEL, sizeof(TLS_SERVER_LABEL));
input += state->hash.final(state->version);
return prf->derive_key(12, state->keys.master_secret(), input);
}
}
}
/*
* Create a new Finished message
*/
Finished::Finished(Record_Writer& writer,
Handshake_State* state,
Connection_Side side)
{
verification_data = finished_compute_verify(state, side);
send(writer, state->hash);
}
/*
* Serialize a Finished message
*/
MemoryVector<byte> Finished::serialize() const
{
return verification_data;
}
/*
* Deserialize a Finished message
*/
Finished::Finished(const MemoryRegion<byte>& buf)
{
verification_data = buf;
}
/*
* Verify a Finished message
*/
bool Finished::verify(Handshake_State* state,
Connection_Side side)
{
return (verification_data == finished_compute_verify(state, side));
}
}
}
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