src/wallet/crypter.cpp

   1 // Copyright (c) 2009-2016 The Bitcoin Core developers
   2 // Distributed under the MIT software license, see the accompanying
   3 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
   4
   5 #include "crypter.h"
   6
   7 #include "crypto/aes.h"
   8 #include "crypto/sha512.h"
   9 #include "script/script.h"
  10 #include "script/standard.h"
  11 #include "util.h"
  12
  13 #include <string>
  14 #include <vector>
  15
  16 int CCrypter::BytesToKeySHA512AES(const std::vector<unsigned char>& chSalt, const SecureString& strKeyData, int count, unsigned char *key,unsigned char *iv) const
  17 {
  18     // This mimics the behavior of openssl's EVP_BytesToKey with an aes256cbc
  19     // cipher and sha512 message digest. Because sha512's output size (64b) is
  20     // greater than the aes256 block size (16b) + aes256 key size (32b),
  21     // there's no need to process more than once (D_0).
  22
  23     if(!count || !key || !iv)
  24         return 0;
  25
  26     unsigned char buf[CSHA512::OUTPUT_SIZE];
  27     CSHA512 di;
  28
  29     di.Write((const unsigned char*)strKeyData.c_str(), strKeyData.size());
  30     if(chSalt.size())
  31         di.Write(&chSalt[0], chSalt.size());
  32     di.Finalize(buf);
  33
  34     for(int i = 0; i != count - 1; i++)
  35         di.Reset().Write(buf, sizeof(buf)).Finalize(buf);
  36
  37     memcpy(key, buf, WALLET_CRYPTO_KEY_SIZE);
  38     memcpy(iv, buf + WALLET_CRYPTO_KEY_SIZE, WALLET_CRYPTO_IV_SIZE);
  39     memory_cleanse(buf, sizeof(buf));
  40     return WALLET_CRYPTO_KEY_SIZE;
  41 }
  42
  43 bool CCrypter::SetKeyFromPassphrase(const SecureString& strKeyData, const std::vector<unsigned char>& chSalt, const unsigned int nRounds, const unsigned int nDerivationMethod)
  44 {
  45     if (nRounds < 1 || chSalt.size() != WALLET_CRYPTO_SALT_SIZE)
  46         return false;
  47
  48     int i = 0;
  49     if (nDerivationMethod == 0)
  50         i = BytesToKeySHA512AES(chSalt, strKeyData, nRounds, vchKey.data(), vchIV.data());
  51
  52     if (i != (int)WALLET_CRYPTO_KEY_SIZE)
  53     {
  54         memory_cleanse(vchKey.data(), vchKey.size());
  55         memory_cleanse(vchIV.data(), vchIV.size());
  56         return false;
  57     }
  58
  59     fKeySet = true;
  60     return true;
  61 }
  62
  63 bool CCrypter::SetKey(const CKeyingMaterial& chNewKey, const std::vector<unsigned char>& chNewIV)
  64 {
  65     if (chNewKey.size() != WALLET_CRYPTO_KEY_SIZE || chNewIV.size() != WALLET_CRYPTO_IV_SIZE)
  66         return false;
  67
  68     memcpy(vchKey.data(), chNewKey.data(), chNewKey.size());
  69     memcpy(vchIV.data(), chNewIV.data(), chNewIV.size());
  70
  71     fKeySet = true;
  72     return true;
  73 }
  74
  75 bool CCrypter::Encrypt(const CKeyingMaterial& vchPlaintext, std::vector<unsigned char> &vchCiphertext) const
  76 {
  77     if (!fKeySet)
  78         return false;
  79
  80     // max ciphertext len for a n bytes of plaintext is
  81     // n + AES_BLOCKSIZE bytes
  82     vchCiphertext.resize(vchPlaintext.size() + AES_BLOCKSIZE);
  83
  84     AES256CBCEncrypt enc(vchKey.data(), vchIV.data(), true);
  85     size_t nLen = enc.Encrypt(&vchPlaintext[0], vchPlaintext.size(), &vchCiphertext[0]);
  86     if(nLen < vchPlaintext.size())
  87         return false;
  88     vchCiphertext.resize(nLen);
  89
  90     return true;
  91 }
  92
  93 bool CCrypter::Decrypt(const std::vector<unsigned char>& vchCiphertext, CKeyingMaterial& vchPlaintext) const
  94 {
  95     if (!fKeySet)
  96         return false;
  97
  98     // plaintext will always be equal to or lesser than length of ciphertext
  99     int nLen = vchCiphertext.size();
 100
 101     vchPlaintext.resize(nLen);
 102
 103     AES256CBCDecrypt dec(vchKey.data(), vchIV.data(), true);
 104     nLen = dec.Decrypt(&vchCiphertext[0], vchCiphertext.size(), &vchPlaintext[0]);
 105     if(nLen == 0)
 106         return false;
 107     vchPlaintext.resize(nLen);
 108     return true;
 109 }
 110
 111
 112 static bool EncryptSecret(const CKeyingMaterial& vMasterKey, const CKeyingMaterial &vchPlaintext, const uint256& nIV, std::vector<unsigned char> &vchCiphertext)
 113 {
 114     CCrypter cKeyCrypter;
 115     std::vector<unsigned char> chIV(WALLET_CRYPTO_IV_SIZE);
 116     memcpy(&chIV[0], &nIV, WALLET_CRYPTO_IV_SIZE);
 117     if(!cKeyCrypter.SetKey(vMasterKey, chIV))
 118         return false;
 119     return cKeyCrypter.Encrypt(*((const CKeyingMaterial*)&vchPlaintext), vchCiphertext);
 120 }
 121
 122 static bool DecryptSecret(const CKeyingMaterial& vMasterKey, const std::vector<unsigned char>& vchCiphertext, const uint256& nIV, CKeyingMaterial& vchPlaintext)
 123 {
 124     CCrypter cKeyCrypter;
 125     std::vector<unsigned char> chIV(WALLET_CRYPTO_IV_SIZE);
 126     memcpy(&chIV[0], &nIV, WALLET_CRYPTO_IV_SIZE);
 127     if(!cKeyCrypter.SetKey(vMasterKey, chIV))
 128         return false;
 129     return cKeyCrypter.Decrypt(vchCiphertext, *((CKeyingMaterial*)&vchPlaintext));
 130 }
 131
 132 static bool DecryptKey(const CKeyingMaterial& vMasterKey, const std::vector<unsigned char>& vchCryptedSecret, const CPubKey& vchPubKey, CKey& key)
 133 {
 134     CKeyingMaterial vchSecret;
 135     if(!DecryptSecret(vMasterKey, vchCryptedSecret, vchPubKey.GetHash(), vchSecret))
 136         return false;
 137
 138     if (vchSecret.size() != 32)
 139         return false;
 140
 141     key.Set(vchSecret.begin(), vchSecret.end(), vchPubKey.IsCompressed());
 142     return key.VerifyPubKey(vchPubKey);
 143 }
 144
 145 bool CCryptoKeyStore::SetCrypted()
 146 {
 147     LOCK(cs_KeyStore);
 148     if (fUseCrypto)
 149         return true;
 150     if (!mapKeys.empty())
 151         return false;
 152     fUseCrypto = true;
 153     return true;
 154 }
 155
 156 bool CCryptoKeyStore::Lock()
 157 {
 158     if (!SetCrypted())
 159         return false;
 160
 161     {
 162         LOCK(cs_KeyStore);
 163         vMasterKey.clear();
 164     }
 165
 166     NotifyStatusChanged(this);
 167     return true;
 168 }
 169
 170 bool CCryptoKeyStore::Unlock(const CKeyingMaterial& vMasterKeyIn)
 171 {
 172     {
 173         LOCK(cs_KeyStore);
 174         if (!SetCrypted())
 175             return false;
 176
 177         bool keyPass = false;
 178         bool keyFail = false;
 179         CryptedKeyMap::const_iterator mi = mapCryptedKeys.begin();
 180         for (; mi != mapCryptedKeys.end(); ++mi)
 181         {
 182             const CPubKey &vchPubKey = (*mi).second.first;
 183             const std::vector<unsigned char> &vchCryptedSecret = (*mi).second.second;
 184             CKey key;
 185             if (!DecryptKey(vMasterKeyIn, vchCryptedSecret, vchPubKey, key))
 186             {
 187                 keyFail = true;
 188                 break;
 189             }
 190             keyPass = true;
 191             if (fDecryptionThoroughlyChecked)
 192                 break;
 193         }
 194         if (keyPass && keyFail)
 195         {
 196             LogPrintf("The wallet is probably corrupted: Some keys decrypt but not all.\n");
 197             assert(false);
 198         }
 199         if (keyFail || !keyPass)
 200             return false;
 201         vMasterKey = vMasterKeyIn;
 202         fDecryptionThoroughlyChecked = true;
 203     }
 204     NotifyStatusChanged(this);
 205     return true;
 206 }
 207
 208 bool CCryptoKeyStore::AddKeyPubKey(const CKey& key, const CPubKey &pubkey)
 209 {
 210     {
 211         LOCK(cs_KeyStore);
 212         if (!IsCrypted())
 213             return CBasicKeyStore::AddKeyPubKey(key, pubkey);
 214
 215         if (IsLocked())
 216             return false;
 217
 218         std::vector<unsigned char> vchCryptedSecret;
 219         CKeyingMaterial vchSecret(key.begin(), key.end());
 220         if (!EncryptSecret(vMasterKey, vchSecret, pubkey.GetHash(), vchCryptedSecret))
 221             return false;
 222
 223         if (!AddCryptedKey(pubkey, vchCryptedSecret))
 224             return false;
 225     }
 226     return true;
 227 }
 228
 229
 230 bool CCryptoKeyStore::AddCryptedKey(const CPubKey &vchPubKey, const std::vector<unsigned char> &vchCryptedSecret)
 231 {
 232     {
 233         LOCK(cs_KeyStore);
 234         if (!SetCrypted())
 235             return false;
 236
 237         mapCryptedKeys[vchPubKey.GetID()] = make_pair(vchPubKey, vchCryptedSecret);
 238     }
 239     return true;
 240 }
 241
 242 bool CCryptoKeyStore::GetKey(const CKeyID &address, CKey& keyOut) const
 243 {
 244     {
 245         LOCK(cs_KeyStore);
 246         if (!IsCrypted())
 247             return CBasicKeyStore::GetKey(address, keyOut);
 248
 249         CryptedKeyMap::const_iterator mi = mapCryptedKeys.find(address);
 250         if (mi != mapCryptedKeys.end())
 251         {
 252             const CPubKey &vchPubKey = (*mi).second.first;
 253             const std::vector<unsigned char> &vchCryptedSecret = (*mi).second.second;
 254             return DecryptKey(vMasterKey, vchCryptedSecret, vchPubKey, keyOut);
 255         }
 256     }
 257     return false;
 258 }
 259
 260 bool CCryptoKeyStore::GetPubKey(const CKeyID &address, CPubKey& vchPubKeyOut) const
 261 {
 262     {
 263         LOCK(cs_KeyStore);
 264         if (!IsCrypted())
 265             return CBasicKeyStore::GetPubKey(address, vchPubKeyOut);
 266
 267         CryptedKeyMap::const_iterator mi = mapCryptedKeys.find(address);
 268         if (mi != mapCryptedKeys.end())
 269         {
 270             vchPubKeyOut = (*mi).second.first;
 271             return true;
 272         }
 273         // Check for watch-only pubkeys
 274         return CBasicKeyStore::GetPubKey(address, vchPubKeyOut);
 275     }
 276 }
 277
 278 bool CCryptoKeyStore::EncryptKeys(CKeyingMaterial& vMasterKeyIn)
 279 {
 280     {
 281         LOCK(cs_KeyStore);
 282         if (!mapCryptedKeys.empty() || IsCrypted())
 283             return false;
 284
 285         fUseCrypto = true;
 286         for (KeyMap::value_type& mKey : mapKeys)
 287         {
 288             const CKey &key = mKey.second;
 289             CPubKey vchPubKey = key.GetPubKey();
 290             CKeyingMaterial vchSecret(key.begin(), key.end());
 291             std::vector<unsigned char> vchCryptedSecret;
 292             if (!EncryptSecret(vMasterKeyIn, vchSecret, vchPubKey.GetHash(), vchCryptedSecret))
 293                 return false;
 294             if (!AddCryptedKey(vchPubKey, vchCryptedSecret))
 295                 return false;
 296         }
 297         mapKeys.clear();
 298     }
 299     return true;
 300 }