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/*
* anytun
*
* The secure anycast tunneling protocol (satp) defines a protocol used
* for communication between any combination of unicast and anycast
* tunnel endpoints. It has less protocol overhead than IPSec in Tunnel
* mode and allows tunneling of every ETHER TYPE protocol (e.g.
* ethernet, ip, arp ...). satp directly includes cryptography and
* message authentication based on the methods used by SRTP. It is
* intended to deliver a generic, scaleable and secure solution for
* tunneling and relaying of packets of any protocol.
*
*
* Copyright (C) 2007-2009 Othmar Gsenger, Erwin Nindl,
* Christian Pointner <satp@wirdorange.org>
*
* This file is part of Anytun.
*
* Anytun is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* any later version.
*
* Anytun is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with anytun. If not, see <http://www.gnu.org/licenses/>.
*/
#include <stdexcept>
#include <iostream>
#include <string>
#include <cstdio>
#include <cstring>
#include "endian.h"
#include "cipher.h"
#if defined(USE_NETTLE)
#include <nettle/ctr.h>
#endif
#include "log.h"
#include "anytunError.h"
void Cipher::encrypt(KeyDerivation& kd, PlainPacket& in, EncryptedPacket& out, seq_nr_t seq_nr, sender_id_t sender_id, mux_t mux)
{
uint32_t len = cipher(kd, in, in.getLength(), out.getPayload(), out.getPayloadLength(), seq_nr, sender_id, mux);
out.setSenderId(sender_id);
out.setSeqNr(seq_nr);
out.setMux(mux);
out.setPayloadLength(len);
}
void Cipher::decrypt(KeyDerivation& kd, EncryptedPacket& in, PlainPacket& out)
{
uint32_t len = decipher(kd, in.getPayload() , in.getPayloadLength(), out, out.getLength(), in.getSeqNr(), in.getSenderId(), in.getMux());
out.setLength(len);
}
//******* NullCipher *******
uint32_t NullCipher::cipher(KeyDerivation& kd, uint8_t* in, uint32_t ilen, uint8_t* out, uint32_t olen, seq_nr_t seq_nr, sender_id_t sender_id, mux_t mux)
{
std::memcpy(out, in, (ilen < olen) ? ilen : olen);
return (ilen < olen) ? ilen : olen;
}
uint32_t NullCipher::decipher(KeyDerivation& kd, uint8_t* in, uint32_t ilen, uint8_t* out, uint32_t olen, seq_nr_t seq_nr, sender_id_t sender_id, mux_t mux)
{
std::memcpy(out, in, (ilen < olen) ? ilen : olen);
return (ilen < olen) ? ilen : olen;
}
#ifndef NO_CRYPT
//****** AesIcmCipher ******
AesIcmCipher::AesIcmCipher(kd_dir_t d) : Cipher(d), key_(uint32_t(DEFAULT_KEY_LENGTH/8)), salt_(uint32_t(SALT_LENGTH))
{
init();
}
AesIcmCipher::AesIcmCipher(kd_dir_t d, uint16_t key_length) : Cipher(d), key_(uint32_t(key_length/8)), salt_(uint32_t(SALT_LENGTH))
{
init(key_length);
}
void AesIcmCipher::init(uint16_t key_length)
{
#if defined(USE_SSL_CRYPTO)
// nothing here
#elif defined(USE_NETTLE)
// nothing here
#else // USE_GCRYPT is the default
handle_ = NULL;
int algo;
switch(key_length) {
case 128:
algo = GCRY_CIPHER_AES128;
break;
case 192:
algo = GCRY_CIPHER_AES192;
break;
case 256:
algo = GCRY_CIPHER_AES256;
break;
default: {
cLog.msg(Log::PRIO_ERROR) << "AesIcmCipher::AesIcmCipher: cipher key length of " << key_length << " Bits is not supported";
return;
}
}
gcry_error_t err = gcry_cipher_open(&handle_, algo, GCRY_CIPHER_MODE_CTR, 0);
if(err) {
cLog.msg(Log::PRIO_ERROR) << "AesIcmCipher::AesIcmCipher: Failed to open cipher" << AnytunGpgError(err);
}
#endif
}
AesIcmCipher::~AesIcmCipher()
{
#if defined(USE_SSL_CRYPTO)
// nothing here
#elif defined(USE_NETTLE)
// nothing here
#else // USE_GCRYPT is the default
if(handle_) {
gcry_cipher_close(handle_);
}
#endif
}
uint32_t AesIcmCipher::cipher(KeyDerivation& kd, uint8_t* in, uint32_t ilen, uint8_t* out, uint32_t olen, seq_nr_t seq_nr, sender_id_t sender_id, mux_t mux)
{
calc(kd, in, ilen, out, olen, seq_nr, sender_id, mux);
return (ilen < olen) ? ilen : olen;
}
uint32_t AesIcmCipher::decipher(KeyDerivation& kd, uint8_t* in, uint32_t ilen, uint8_t* out, uint32_t olen, seq_nr_t seq_nr, sender_id_t sender_id, mux_t mux)
{
calc(kd, in, ilen, out, olen, seq_nr, sender_id, mux);
return (ilen < olen) ? ilen : olen;
}
void AesIcmCipher::calcCtr(KeyDerivation& kd, seq_nr_t seq_nr, sender_id_t sender_id, mux_t mux)
{
kd.generate(dir_, LABEL_SALT, seq_nr, salt_);
std::memcpy(ctr_.salt_.buf_, salt_.getBuf(), SALT_LENGTH);
ctr_.salt_.zero_ = 0;
ctr_.params_.mux_ ^= MUX_T_HTON(mux);
ctr_.params_.sender_id_ ^= SENDER_ID_T_HTON(sender_id);
ctr_.params_.seq_nr_ ^= SEQ_NR_T_HTON(seq_nr);
return;
}
void AesIcmCipher::calc(KeyDerivation& kd, uint8_t* in, uint32_t ilen, uint8_t* out, uint32_t olen, seq_nr_t seq_nr, sender_id_t sender_id, mux_t mux)
{
#if defined(USE_GCRYPT)
if(!handle_) {
return;
}
#endif
kd.generate(dir_, LABEL_ENC, seq_nr, key_);
#if defined(USE_SSL_CRYPTO)
int ret = AES_set_encrypt_key(key_.getBuf(), key_.getLength()*8, &aes_key_);
if(ret) {
cLog.msg(Log::PRIO_ERROR) << "AesIcmCipher: Failed to set cipher ssl key (code: " << ret << ")";
return;
}
#elif defined(USE_NETTLE)
aes_set_encrypt_key(&ctx_, key_.getLength(), key_.getBuf());
#else // USE_GCRYPT is the default
gcry_error_t err = gcry_cipher_setkey(handle_, key_.getBuf(), key_.getLength());
if(err) {
cLog.msg(Log::PRIO_ERROR) << "AesIcmCipher: Failed to set cipher key: " << AnytunGpgError(err);
return;
}
#endif
calcCtr(kd, seq_nr, sender_id, mux);
#if defined(USE_SSL_CRYPTO)
if(CTR_LENGTH != AES_BLOCK_SIZE) {
cLog.msg(Log::PRIO_ERROR) << "AesIcmCipher: Failed to set cipher CTR: size doesn't fit";
return;
}
unsigned int num = 0;
std::memset(ecount_buf_, 0, AES_BLOCK_SIZE);
AES_ctr128_encrypt(in, out, (ilen < olen) ? ilen : olen, &aes_key_, ctr_.buf_, ecount_buf_, &num);
#elif defined(USE_NETTLE)
if(CTR_LENGTH != AES_BLOCK_SIZE) {
cLog.msg(Log::PRIO_ERROR) << "AesIcmCipher: Failed to set cipher CTR: size doesn't fit";
return;
}
ctr_crypt(&ctx_, (nettle_crypt_func *)(aes_encrypt), AES_BLOCK_SIZE, ctr_.buf_, (ilen < olen) ? ilen : olen, out, in);
#else // USE_GCRYPT is the default
err = gcry_cipher_setctr(handle_, ctr_.buf_, CTR_LENGTH);
if(err) {
cLog.msg(Log::PRIO_ERROR) << "AesIcmCipher: Failed to set cipher CTR: " << AnytunGpgError(err);
return;
}
err = gcry_cipher_encrypt(handle_, out, olen, in, ilen);
if(err) {
cLog.msg(Log::PRIO_ERROR) << "AesIcmCipher: Failed to de/encrypt packet: " << AnytunGpgError(err);
return;
}
#endif
}
#endif
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