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/* Copyright (C) 2010 Marc Maurer <uwog@uwog.net>
*
* 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, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301 USA.
*/
#include <stdlib.h>
#include <zlib.h>
#include <glib.h>
#include <gsf/gsf-input-gzip.h>
#include <gsf/gsf-input-memory.h>
#include "sha1.h"
#include "gc-pbkdf2-sha1.h"
#include "ut_assert.h"
#include "ut_debugmsg.h"
#include "ODc_Crypto.h"
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#ifdef HAVE_GCRYPT
#include "gcrypt.h"
#endif
#define PASSWORD_HASH_LEN 20
#define PBKDF2_KEYLEN 16
#define HANDLEGERR(e) \
{ \
gcry_err_code_t code = gcry_err_code(e); \
if( code != GPG_ERR_NO_ERROR ) \
{ \
switch(code) \
{ \
case GPG_ERR_ENOMEM: \
return UT_OUTOFMEM; \
case GPG_ERR_DECRYPT_FAILED: \
return UT_IE_PROTECTED; \
default: \
return UT_ERROR; \
} \
} \
}
UT_Error ODc_Crypto::performDecrypt(GsfInput* pStream,
unsigned char* salt, UT_uint32 salt_length, UT_uint32 iter_count,
unsigned char* ivec, gsize ivec_length, const std::string& password, UT_uint32 decrypted_size,
GsfInput** pDecryptedInput)
{
unsigned char sha1_password[PASSWORD_HASH_LEN];
char key[PBKDF2_KEYLEN];
// get the sha1 sum of the password
sha1_buffer(&password[0], password.size(), sha1_password);
// create a PBKDF2 key from the sha1 sum
int k = pbkdf2_sha1 ((const char*)sha1_password, PASSWORD_HASH_LEN, (const char*)salt, salt_length, iter_count, key, PBKDF2_KEYLEN);
if (k != 0)
return UT_ERROR;
// Get the encrypted content ready
UT_sint32 content_size = gsf_input_size(pStream);
if (content_size == -1)
return UT_ERROR;
const unsigned char* content = gsf_input_read(pStream, content_size, NULL);
if (!content)
return UT_ERROR;
unsigned char* content_decrypted = (unsigned char*)g_malloc(content_size);
// perform the actual decryption
#ifdef HAVE_GCRYPT
UT_DEBUGMSG(("ODc_Crypto::performDecrypt() using gcrypt\n" ));
gcry_cipher_hd_t h;
HANDLEGERR( gcry_cipher_open( &h,
GCRY_CIPHER_BLOWFISH,
GCRY_CIPHER_MODE_CFB,
0 ));
HANDLEGERR( gcry_cipher_setkey( h, key, PBKDF2_KEYLEN ));
HANDLEGERR( gcry_cipher_setiv ( h, ivec, ivec_length ));
HANDLEGERR( gcry_cipher_decrypt( h,
content_decrypted,
content_size,
content,
content_size ));
gcry_cipher_close( h );
#else
// removed old blowfish code
#endif
// deflate the decrypted content
z_stream zs;
zs.zalloc = Z_NULL;
zs.zfree = Z_NULL;
zs.opaque = Z_NULL;
zs.avail_in = 0;
zs.next_in = Z_NULL;
int err;
err = inflateInit2(&zs, -MAX_WBITS);
if (err != Z_OK)
return UT_ERROR;
unsigned char* decrypted = (unsigned char*)g_malloc(decrypted_size);
zs.avail_in = content_size;
zs.avail_out = decrypted_size;
zs.next_in = content_decrypted;
zs.next_out = decrypted;
err = inflate(&zs, Z_FINISH);
FREEP(content_decrypted);
if (err != Z_STREAM_END)
{
inflateEnd(&zs);
FREEP(decrypted);
return UT_ERROR;
}
inflateEnd(&zs);
*pDecryptedInput = gsf_input_memory_new(decrypted, decrypted_size, TRUE);
return UT_OK;
}
UT_Error ODc_Crypto::decrypt(GsfInput* pStream, const ODc_CryptoInfo& cryptInfo,
const std::string& password, GsfInput** pDecryptedInput)
{
UT_return_val_if_fail(pStream, UT_ERROR);
UT_return_val_if_fail(pDecryptedInput, UT_ERROR);
// check if we support the requested decryption method
UT_return_val_if_fail(g_ascii_strcasecmp(cryptInfo.m_algorithm.c_str(), "Blowfish CFB") == 0, UT_ERROR);
UT_return_val_if_fail(g_ascii_strcasecmp(cryptInfo.m_keyType.c_str(), "PBKDF2") == 0, UT_ERROR);
// base64 decode the salt
gsize salt_length;
unsigned char* salt = g_base64_decode(cryptInfo.m_salt.c_str(), &salt_length);
// base64 decode the initialization vector
gsize ivec_length;
unsigned char* ivec = g_base64_decode(cryptInfo.m_initVector.c_str(), &ivec_length);
// decrypt the content
UT_Error result = performDecrypt(pStream, salt, salt_length, cryptInfo.m_iterCount,
ivec, ivec_length, password, cryptInfo.m_decryptedSize, pDecryptedInput);
// cleanup
FREEP(salt);
FREEP(ivec);
return result;
}
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