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/**
* @file llblowfishcipher.cpp
* @brief Wrapper around OpenSSL Blowfish encryption algorithm.
*
* $LicenseInfo:firstyear=2007&license=viewerlgpl$
* Second Life Viewer Source Code
* Copyright (C) 2010, Linden Research, Inc.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation;
* version 2.1 of the License only.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*
* Linden Research, Inc., 945 Battery Street, San Francisco, CA 94111 USA
* $/LicenseInfo$
*/
#include "linden_common.h"
#include "llblowfishcipher.h"
#include <openssl/evp.h>
LLBlowfishCipher::LLBlowfishCipher(const U8* secret, size_t secret_size)
: LLCipher()
{
llassert(secret);
mSecretSize = secret_size;
mSecret = new U8[mSecretSize];
memcpy(mSecret, secret, mSecretSize);
}
LLBlowfishCipher::~LLBlowfishCipher()
{
delete [] mSecret;
mSecret = NULL;
}
// virtual
U32 LLBlowfishCipher::encrypt(const U8* src, U32 src_len, U8* dst, U32 dst_len)
{
if (!src || !src_len || !dst || !dst_len) return 0;
if (src_len > dst_len) return 0;
// OpenSSL uses "cipher contexts" to hold encryption parameters.
EVP_CIPHER_CTX context;
EVP_CIPHER_CTX_init(&context);
// We want a blowfish cyclic block chain cipher, but need to set
// the key length before we pass in a key, so call EncryptInit
// first with NULLs.
EVP_EncryptInit_ex(&context, EVP_bf_cbc(), NULL, NULL, NULL);
EVP_CIPHER_CTX_set_key_length(&context, (int)mSecretSize);
// Complete initialization. Per EVP_EncryptInit man page, the
// cipher pointer must be NULL. Apparently initial_vector must
// be 8 bytes for blowfish, as this is the block size.
unsigned char initial_vector[] = { 0, 0, 0, 0, 0, 0, 0, 0 };
EVP_EncryptInit_ex(&context, NULL, NULL, mSecret, initial_vector);
int blocksize = EVP_CIPHER_CTX_block_size(&context);
int keylen = EVP_CIPHER_CTX_key_length(&context);
int iv_length = EVP_CIPHER_CTX_iv_length(&context);
lldebugs << "LLBlowfishCipher blocksize " << blocksize
<< " keylen " << keylen
<< " iv_len " << iv_length
<< llendl;
int output_len = 0;
int temp_len = 0;
if (!EVP_EncryptUpdate(&context,
dst,
&output_len,
src,
src_len))
{
llwarns << "LLBlowfishCipher::encrypt EVP_EncryptUpdate failure" << llendl;
goto ERROR;
}
// There may be some final data left to encrypt if the input is
// not an exact multiple of the block size.
if (!EVP_EncryptFinal_ex(&context, (unsigned char*)(dst + output_len), &temp_len))
{
llwarns << "LLBlowfishCipher::encrypt EVP_EncryptFinal failure" << llendl;
goto ERROR;
}
output_len += temp_len;
EVP_CIPHER_CTX_cleanup(&context);
return output_len;
ERROR:
EVP_CIPHER_CTX_cleanup(&context);
return 0;
}
// virtual
U32 LLBlowfishCipher::decrypt(const U8* src, U32 src_len, U8* dst, U32 dst_len)
{
llerrs << "LLBlowfishCipher decrypt unsupported" << llendl;
return 0;
}
// virtual
U32 LLBlowfishCipher::requiredEncryptionSpace(U32 len) const
{
// *HACK: We know blowfish uses an 8 byte block size.
// Oddly, sometimes EVP_Encrypt produces an extra block
// if the input is an exact multiple of the block size.
// So round up.
const U32 BLOCK_SIZE = 8;
len += BLOCK_SIZE;
len -= (len % BLOCK_SIZE);
return len;
}
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