wanproxy/ssh/ssh_encryption.cc
2015-08-31 14:01:44 +02:00

128 lines
4.7 KiB
C++

/*
* Copyright (c) 2011-2012 Juli Mallett. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <common/buffer.h>
#include <ssh/ssh_algorithm_negotiation.h>
#include <ssh/ssh_encryption.h>
#include <ssh/ssh_session.h>
namespace {
struct ssh_encryption_algorithm {
const char *rfc4250_name_;
CryptoEncryption::Algorithm crypto_algorithm_;
CryptoEncryption::Mode crypto_mode_;
};
static const struct ssh_encryption_algorithm ssh_encryption_algorithms[] = {
{ "aes128-ctr", CryptoEncryption::AES128, CryptoEncryption::CTR },
{ "aes128-cbc", CryptoEncryption::AES128, CryptoEncryption::CBC },
{ "aes192-ctr", CryptoEncryption::AES192, CryptoEncryption::CTR },
{ "aes192-cbc", CryptoEncryption::AES192, CryptoEncryption::CBC },
{ "aes256-ctr", CryptoEncryption::AES256, CryptoEncryption::CTR },
{ "aes256-cbc", CryptoEncryption::AES256, CryptoEncryption::CBC },
{ "blowfish-ctr", CryptoEncryption::Blowfish, CryptoEncryption::CTR },
{ "blowfish-cbc", CryptoEncryption::Blowfish, CryptoEncryption::CBC },
{ "3des-ctr", CryptoEncryption::TripleDES, CryptoEncryption::CTR },
{ "3des-cbc", CryptoEncryption::TripleDES, CryptoEncryption::CBC },
{ "cast128-cbc", CryptoEncryption::CAST, CryptoEncryption::CBC },
{ "idea-cbc", CryptoEncryption::IDEA, CryptoEncryption::CBC },
{ "arcfour", CryptoEncryption::RC4, CryptoEncryption::Stream},
{ NULL, CryptoEncryption::AES128, CryptoEncryption::CBC }
};
class CryptoSSHEncryption : public SSH::Encryption {
LogHandle log_;
CryptoEncryption::Session *session_;
public:
CryptoSSHEncryption(const std::string& xname, CryptoEncryption::Session *session)
: SSH::Encryption(xname, session->block_size(), session->key_size(), session->iv_size()),
log_("/ssh/encryption/crypto/" + xname),
session_(session)
{ }
~CryptoSSHEncryption()
{ }
Encryption *clone(void) const
{
return (new CryptoSSHEncryption(name_, session_->clone()));
}
bool initialize(CryptoEncryption::Operation operation, const Buffer *key, const Buffer *iv)
{
return (session_->initialize(operation, key, iv));
}
bool cipher(Buffer *out, Buffer *in)
{
if (!session_->cipher(out, in)) {
in->clear();
return (false);
}
in->clear();
return (true);
}
};
}
void
SSH::Encryption::add_algorithms(Session *session)
{
const struct ssh_encryption_algorithm *alg;
for (alg = ssh_encryption_algorithms; alg->rfc4250_name_ != NULL; alg++) {
Encryption *encryption = cipher(CryptoEncryption::Cipher(alg->crypto_algorithm_, alg->crypto_mode_));
if (encryption == NULL)
continue;
session->algorithm_negotiation_->add_algorithm(encryption);
}
}
SSH::Encryption *
SSH::Encryption::cipher(CryptoEncryption::Cipher cipher)
{
const struct ssh_encryption_algorithm *alg;
for (alg = ssh_encryption_algorithms; alg->rfc4250_name_ != NULL; alg++) {
if (cipher.first != alg->crypto_algorithm_)
continue;
if (cipher.second != alg->crypto_mode_)
continue;
const CryptoEncryption::Method *method = CryptoEncryption::Method::method(cipher);
if (method == NULL) {
DEBUG("/ssh/encryption") << "Could not get method for cipher: " << cipher;
return (NULL);
}
CryptoEncryption::Session *session = method->session(cipher);
if (session == NULL) {
ERROR("/ssh/encryption") << "Could not get session for cipher: " << cipher;
return (NULL);
}
return (new CryptoSSHEncryption(alg->rfc4250_name_, session));
}
DEBUG("/ssh/encryption") << "No SSH encryption support is available for cipher: " << cipher;
return (NULL);
}