AES.cpp

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/*
 * This file is part of the TrinityCore Project. See AUTHORS file for Copyright information
 *
 * This program 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 2 of the License, or (at your
 * option) any later version.
 *
 * This program 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 this program. If not, see <http://www.gnu.org/licenses/>.
 */
 
#include "AES.h"
#include "Errors.h"
#include <limits>
 
Trinity::Crypto::AES::AES(bool encrypting, size_t keySizeBits /*= 128*/) : _ctx(EVP_CIPHER_CTX_new()), _encrypting(encrypting)
{
    EVP_CIPHER_CTX_init(_ctx);
    EVP_CIPHER const* cipher = nullptr;
    switch (keySizeBits)
    {
        case 128:
            cipher = EVP_aes_128_gcm();
            break;
        case 192:
            cipher = EVP_aes_192_gcm();
            break;
        case 256:
            cipher = EVP_aes_256_gcm();
            break;
        default:
            ASSERT(false, "Invalid AES key size " SZFMTD, keySizeBits);
    }
 
    int status = EVP_CipherInit_ex(_ctx, cipher, nullptr, nullptr, nullptr, _encrypting ? 1 : 0);
    ASSERT(status);
}
 
Trinity::Crypto::AES::~AES()
{
    EVP_CIPHER_CTX_free(_ctx);
}
 
void Trinity::Crypto::AES::Init(Key const& key)
{
    int status = EVP_CipherInit_ex(_ctx, nullptr, nullptr, key.data(), nullptr, -1);
    ASSERT(status);
}
 
void Trinity::Crypto::AES::Init(std::span<uint8 const> key)
{
    ASSERT(key.size() == size_t(EVP_CIPHER_CTX_get_key_length(_ctx)));
    int status = EVP_CipherInit_ex(_ctx, nullptr, nullptr, key.data(), nullptr, -1);
    ASSERT(status);
}
 
bool Trinity::Crypto::AES::Process(IV const& iv, uint8* data, size_t length, Tag& tag)
{
    ASSERT(length <= static_cast<size_t>(std::numeric_limits<int>::max()));
    int len = static_cast<int>(length);
    if (!EVP_CipherInit_ex(_ctx, nullptr, nullptr, nullptr, iv.data(), -1))
        return false;
 
    int outLen;
    if (!EVP_CipherUpdate(_ctx, data, &outLen, data, len))
        return false;
 
    len -= outLen;
 
    if (!_encrypting && !EVP_CIPHER_CTX_ctrl(_ctx, EVP_CTRL_GCM_SET_TAG, sizeof(tag), tag))
        return false;
 
    if (!EVP_CipherFinal_ex(_ctx, data + outLen, &outLen))
        return false;
 
    ASSERT(len == outLen);
 
    if (_encrypting && !EVP_CIPHER_CTX_ctrl(_ctx, EVP_CTRL_GCM_GET_TAG, sizeof(tag), tag))
        return false;
 
    return true;
}
 
bool Trinity::Crypto::AES::ProcessNoIntegrityCheck(IV const& iv, uint8* data, size_t partialLength)
{
    ASSERT(!_encrypting, "Partial encryption is not allowed");
    ASSERT(partialLength <= static_cast<size_t>(std::numeric_limits<int>::max()));
    int len = static_cast<int>(partialLength);
    if (!EVP_CipherInit_ex(_ctx, nullptr, nullptr, nullptr, iv.data(), -1))
        return false;
 
    int outLen;
    if (!EVP_CipherUpdate(_ctx, data, &outLen, data, len))
        return false;
 
    len -= outLen;
 
    if (!EVP_CipherFinal_ex(_ctx, data + outLen, &outLen))
        return false;
 
    ASSERT(len == outLen);
 
    return true;
}