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/**
* TLS Record Writing
* (C) 2004-2010 Jack Lloyd
*
* Released under the terms of the Botan license
*/
#include <botan/tls_record.h>
#include <botan/handshake_hash.h>
#include <botan/lookup.h>
#include <botan/loadstor.h>
namespace Botan {
/**
* Record_Writer Constructor
*/
Record_Writer::Record_Writer(Socket& sock) :
socket(sock), buffer(DEFAULT_BUFFERSIZE)
{
reset();
}
/**
* Reset the state
*/
void Record_Writer::reset()
{
cipher.reset();
mac.reset();
buffer.clear();
buf_pos = 0;
major = minor = buf_type = 0;
block_size = 0;
mac_size = 0;
seq_no = 0;
}
/**
* Set the version to use
*/
void Record_Writer::set_version(Version_Code version)
{
if(version != SSL_V3 && version != TLS_V10)
throw Invalid_Argument("Record_Writer: Invalid protocol version");
major = (version >> 8) & 0xFF;
minor = (version & 0xFF);
}
/**
* Set the keys for writing
*/
void Record_Writer::set_keys(const CipherSuite& suite, const SessionKeys& keys,
Connection_Side side)
{
cipher.reset();
mac.reset();
SymmetricKey mac_key, cipher_key;
InitializationVector iv;
if(side == CLIENT)
{
cipher_key = keys.client_cipher_key();
iv = keys.client_iv();
mac_key = keys.client_mac_key();
}
else
{
cipher_key = keys.server_cipher_key();
iv = keys.server_iv();
mac_key = keys.server_mac_key();
}
const std::string cipher_algo = suite.cipher_algo();
const std::string mac_algo = suite.mac_algo();
if(have_block_cipher(cipher_algo))
{
cipher.append(get_cipher(
cipher_algo + "/CBC/NoPadding",
cipher_key, iv, ENCRYPTION)
);
block_size = block_size_of(cipher_algo);
}
else if(have_stream_cipher(cipher_algo))
{
cipher.append(get_cipher(cipher_algo, cipher_key, ENCRYPTION));
block_size = 0;
}
else
throw Invalid_Argument("Record_Writer: Unknown cipher " + cipher_algo);
if(have_hash(mac_algo))
{
if(major == 3 && minor == 0)
mac.append(new MAC_Filter("SSL3-MAC(" + mac_algo + ")", mac_key));
else
mac.append(new MAC_Filter("HMAC(" + mac_algo + ")", mac_key));
mac_size = output_length_of(mac_algo);
}
else
throw Invalid_Argument("Record_Writer: Unknown hash " + mac_algo);
}
/**
* Send one or more records to the other side
*/
void Record_Writer::send(byte type, byte input)
{
send(type, &input, 1);
}
/**
* Send one or more records to the other side
*/
void Record_Writer::send(byte type, const byte input[], u32bit length)
{
if(type != buf_type)
flush();
const u32bit BUFFER_SIZE = buffer.size();
buf_type = type;
// FIXME: compression right here
buffer.copy(buf_pos, input, length);
if(buf_pos + length >= BUFFER_SIZE)
{
send_record(buf_type, buffer, length);
input += (BUFFER_SIZE - buf_pos);
length -= (BUFFER_SIZE - buf_pos);
while(length >= BUFFER_SIZE)
{
send_record(buf_type, input, BUFFER_SIZE);
input += BUFFER_SIZE;
length -= BUFFER_SIZE;
}
buffer.copy(input, length);
buf_pos = 0;
}
buf_pos += length;
}
/**
* Split buffer into records, and send them all
*/
void Record_Writer::flush()
{
const byte* buf_ptr = buffer.begin();
u32bit offset = 0;
while(offset != buf_pos)
{
u32bit record_size = buf_pos - offset;
if(record_size > MAX_PLAINTEXT_SIZE)
record_size = MAX_PLAINTEXT_SIZE;
send_record(buf_type, buf_ptr + offset, record_size);
offset += record_size;
}
buf_type = 0;
buf_pos = 0;
}
/**
* Encrypt and send the record
*/
void Record_Writer::send_record(byte type, const byte buf[], u32bit length)
{
if(length >= MAX_COMPRESSED_SIZE)
throw TLS_Exception(INTERNAL_ERROR,
"Record_Writer: Compressed packet is too big");
if(mac_size == 0)
send_record(type, major, minor, buf, length);
else
{
mac.start_msg();
for(u32bit j = 0; j != 8; j++)
mac.write(get_byte(j, seq_no));
mac.write(type);
if(major > 3 || (major == 3 && minor != 0))
{
mac.write(major);
mac.write(minor);
}
mac.write(get_byte(2, length));
mac.write(get_byte(3, length));
mac.write(buf, length);
mac.end_msg();
// TODO: This could all use a single buffer
SecureVector<byte> buf_mac = mac.read_all(Pipe::LAST_MESSAGE);
cipher.start_msg();
cipher.write(buf, length);
cipher.write(buf_mac);
if(block_size)
{
u32bit pad_val =
(block_size - (1 + length + buf_mac.size())) % block_size;
for(u32bit j = 0; j != pad_val + 1; j++)
cipher.write(pad_val);
}
cipher.end_msg();
SecureVector<byte> output = cipher.read_all(Pipe::LAST_MESSAGE);
send_record(type, major, minor, output, output.size());
seq_no++;
}
}
/**
* Send a final record packet
*/
void Record_Writer::send_record(byte type, byte major, byte minor,
const byte out[], u32bit length)
{
if(length >= MAX_CIPHERTEXT_SIZE)
throw TLS_Exception(INTERNAL_ERROR,
"Record_Writer: Record is too big");
byte header[5] = { type, major, minor, 0 };
for(u32bit j = 0; j != 2; j++)
header[j+3] = get_byte<u16bit>(j, length);
socket.write(header, 5);
socket.write(out, length);
}
/**
* Send an alert
*/
void Record_Writer::alert(Alert_Level level, Alert_Type type)
{
byte alert[2] = { level, type };
send(ALERT, alert, sizeof(alert));
flush();
}
}
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