0f8a647782
As memset() can be optimized out by a compiler it should not be used in privacy/security relevant code parts. OpenSSL provides the safe OPENSSL_cleanse() function in crypto.h, which perfectly does the job of clean and overwrite data. For details see: http://www.viva64.com/en/b/0178/ - change memset() to OPENSSL_cleanse() where appropriate - change a hard-coded number from netbase.cpp into a sizeof()
122 lines
3.8 KiB
C++
122 lines
3.8 KiB
C++
// Copyright (c) 2009-2012 The Bitcoin Developers
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// Distributed under the MIT/X11 software license, see the accompanying
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// file COPYING or http://www.opensource.org/licenses/mit-license.php.
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#include <openssl/aes.h>
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#include <openssl/evp.h>
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#include <vector>
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#include <string>
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#ifdef WIN32
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#include <windows.h>
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#endif
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#include "crypter.h"
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bool CCrypter::SetKeyFromPassphrase(const SecureString& strKeyData, const std::vector<unsigned char>& chSalt, const unsigned int nRounds, const unsigned int nDerivationMethod)
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{
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if (nRounds < 1 || chSalt.size() != WALLET_CRYPTO_SALT_SIZE)
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return false;
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int i = 0;
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if (nDerivationMethod == 0)
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i = EVP_BytesToKey(EVP_aes_256_cbc(), EVP_sha512(), &chSalt[0],
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(unsigned char *)&strKeyData[0], strKeyData.size(), nRounds, chKey, chIV);
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if (i != (int)WALLET_CRYPTO_KEY_SIZE)
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{
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OPENSSL_cleanse(chKey, sizeof(chKey));
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OPENSSL_cleanse(chIV, sizeof(chIV));
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return false;
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}
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fKeySet = true;
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return true;
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}
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bool CCrypter::SetKey(const CKeyingMaterial& chNewKey, const std::vector<unsigned char>& chNewIV)
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{
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if (chNewKey.size() != WALLET_CRYPTO_KEY_SIZE || chNewIV.size() != WALLET_CRYPTO_KEY_SIZE)
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return false;
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memcpy(&chKey[0], &chNewKey[0], sizeof chKey);
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memcpy(&chIV[0], &chNewIV[0], sizeof chIV);
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fKeySet = true;
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return true;
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}
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bool CCrypter::Encrypt(const CKeyingMaterial& vchPlaintext, std::vector<unsigned char> &vchCiphertext)
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{
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if (!fKeySet)
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return false;
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// max ciphertext len for a n bytes of plaintext is
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// n + AES_BLOCK_SIZE - 1 bytes
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int nLen = vchPlaintext.size();
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int nCLen = nLen + AES_BLOCK_SIZE, nFLen = 0;
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vchCiphertext = std::vector<unsigned char> (nCLen);
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EVP_CIPHER_CTX ctx;
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bool fOk = true;
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EVP_CIPHER_CTX_init(&ctx);
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if (fOk) fOk = EVP_EncryptInit_ex(&ctx, EVP_aes_256_cbc(), NULL, chKey, chIV);
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if (fOk) fOk = EVP_EncryptUpdate(&ctx, &vchCiphertext[0], &nCLen, &vchPlaintext[0], nLen);
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if (fOk) fOk = EVP_EncryptFinal_ex(&ctx, (&vchCiphertext[0])+nCLen, &nFLen);
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EVP_CIPHER_CTX_cleanup(&ctx);
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if (!fOk) return false;
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vchCiphertext.resize(nCLen + nFLen);
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return true;
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}
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bool CCrypter::Decrypt(const std::vector<unsigned char>& vchCiphertext, CKeyingMaterial& vchPlaintext)
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{
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if (!fKeySet)
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return false;
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// plaintext will always be equal to or lesser than length of ciphertext
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int nLen = vchCiphertext.size();
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int nPLen = nLen, nFLen = 0;
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vchPlaintext = CKeyingMaterial(nPLen);
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EVP_CIPHER_CTX ctx;
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bool fOk = true;
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EVP_CIPHER_CTX_init(&ctx);
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if (fOk) fOk = EVP_DecryptInit_ex(&ctx, EVP_aes_256_cbc(), NULL, chKey, chIV);
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if (fOk) fOk = EVP_DecryptUpdate(&ctx, &vchPlaintext[0], &nPLen, &vchCiphertext[0], nLen);
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if (fOk) fOk = EVP_DecryptFinal_ex(&ctx, (&vchPlaintext[0])+nPLen, &nFLen);
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EVP_CIPHER_CTX_cleanup(&ctx);
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if (!fOk) return false;
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vchPlaintext.resize(nPLen + nFLen);
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return true;
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}
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bool EncryptSecret(CKeyingMaterial& vMasterKey, const CSecret &vchPlaintext, const uint256& nIV, std::vector<unsigned char> &vchCiphertext)
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{
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CCrypter cKeyCrypter;
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std::vector<unsigned char> chIV(WALLET_CRYPTO_KEY_SIZE);
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memcpy(&chIV[0], &nIV, WALLET_CRYPTO_KEY_SIZE);
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if(!cKeyCrypter.SetKey(vMasterKey, chIV))
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return false;
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return cKeyCrypter.Encrypt((CKeyingMaterial)vchPlaintext, vchCiphertext);
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}
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bool DecryptSecret(const CKeyingMaterial& vMasterKey, const std::vector<unsigned char>& vchCiphertext, const uint256& nIV, CSecret& vchPlaintext)
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{
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CCrypter cKeyCrypter;
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std::vector<unsigned char> chIV(WALLET_CRYPTO_KEY_SIZE);
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memcpy(&chIV[0], &nIV, WALLET_CRYPTO_KEY_SIZE);
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if(!cKeyCrypter.SetKey(vMasterKey, chIV))
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return false;
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return cKeyCrypter.Decrypt(vchCiphertext, *((CKeyingMaterial*)&vchPlaintext));
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}
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