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/*
This file is part of cpp-ethereum.
cpp-ethereum 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 3 of the License, or
(at your option) any later version.
cpp-ethereum 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 cpp-ethereum. If not, see <http://www.gnu.org/licenses/>.
*/
/** @file SecretStore.cpp
* @author Gav Wood <i@gavwood.com>
* @date 2014
*/
#include "SecretStore.h"
#include <thread>
#include <mutex>
#include <boost/algorithm/string.hpp>
#include <boost/filesystem.hpp>
#include <libdevcore/Log.h>
#include <libdevcore/Guards.h>
#include <libdevcore/SHA3.h>
#include <libdevcore/FileSystem.h>
#include <test/JsonSpiritHeaders.h>
#include <libdevcrypto/Exceptions.h>
using namespace std;
using namespace dev;
namespace js = json_spirit;
namespace fs = boost::filesystem;
static const int c_keyFileVersion = 3;
/// Upgrade the json-format to the current version.
static js::mValue upgraded(string const& _s)
{
js::mValue v;
js::read_string(_s, v);
if (v.type() != js::obj_type)
return js::mValue();
js::mObject ret = v.get_obj();
unsigned version = ret.count("Version") ? stoi(ret["Version"].get_str()) : ret.count("version") ? ret["version"].get_int() : 0;
if (version == 1)
{
// upgrade to version 2
js::mObject old;
swap(old, ret);
ret["id"] = old["Id"];
js::mObject c;
c["ciphertext"] = old["Crypto"].get_obj()["CipherText"];
c["cipher"] = "aes-128-cbc";
{
js::mObject cp;
cp["iv"] = old["Crypto"].get_obj()["IV"];
c["cipherparams"] = cp;
}
c["kdf"] = old["Crypto"].get_obj()["KeyHeader"].get_obj()["Kdf"];
{
js::mObject kp;
kp["salt"] = old["Crypto"].get_obj()["Salt"];
for (auto const& i: old["Crypto"].get_obj()["KeyHeader"].get_obj()["KdfParams"].get_obj())
if (i.first != "SaltLen")
kp[boost::to_lower_copy(i.first)] = i.second;
c["kdfparams"] = kp;
}
c["sillymac"] = old["Crypto"].get_obj()["MAC"];
c["sillymacjson"] = _s;
ret["crypto"] = c;
version = 2;
}
if (version == 2)
{
ret["crypto"].get_obj()["cipher"] = "aes-128-ctr";
ret["crypto"].get_obj()["compat"] = "2";
version = 3;
}
if (version == c_keyFileVersion)
return ret;
return js::mValue();
}
SecretStore::SecretStore(string const& _path): m_path(_path)
{
load();
}
bytesSec SecretStore::secret(h128 const& _uuid, function<string()> const& _pass, bool _useCache) const
{
auto rit = m_cached.find(_uuid);
if (_useCache && rit != m_cached.end())
return rit->second;
auto it = m_keys.find(_uuid);
bytesSec key;
if (it != m_keys.end())
{
key = bytesSec(decrypt(it->second.encryptedKey, _pass()));
if (!key.empty())
m_cached[_uuid] = key;
}
return key;
}
h128 SecretStore::importSecret(bytesSec const& _s, string const& _pass)
{
h128 r;
EncryptedKey key{encrypt(_s.ref(), _pass), string()};
r = h128::random();
m_cached[r] = _s;
m_keys[r] = move(key);
save();
return r;
}
h128 SecretStore::importSecret(bytesConstRef _s, string const& _pass)
{
h128 r;
EncryptedKey key{encrypt(_s, _pass), string()};
r = h128::random();
m_cached[r] = bytesSec(_s);
m_keys[r] = move(key);
save();
return r;
}
void SecretStore::kill(h128 const& _uuid)
{
m_cached.erase(_uuid);
if (m_keys.count(_uuid))
{
fs::remove(m_keys[_uuid].filename);
m_keys.erase(_uuid);
}
}
void SecretStore::clearCache() const
{
m_cached.clear();
}
void SecretStore::save(string const& _keysPath)
{
fs::path p(_keysPath);
fs::create_directories(p);
DEV_IGNORE_EXCEPTIONS(fs::permissions(p, fs::owner_all));
for (auto& k: m_keys)
{
string uuid = toUUID(k.first);
string filename = (p / uuid).string() + ".json";
js::mObject v;
js::mValue crypto;
js::read_string(k.second.encryptedKey, crypto);
v["crypto"] = crypto;
v["id"] = uuid;
v["version"] = c_keyFileVersion;
writeFile(filename, js::write_string(js::mValue(v), true));
swap(k.second.filename, filename);
if (!filename.empty() && !fs::equivalent(filename, k.second.filename))
fs::remove(filename);
}
}
void SecretStore::load(string const& _keysPath)
{
fs::path p(_keysPath);
fs::create_directories(p);
DEV_IGNORE_EXCEPTIONS(fs::permissions(p, fs::owner_all));
for (fs::directory_iterator it(p); it != fs::directory_iterator(); ++it)
if (fs::is_regular_file(it->path()))
readKey(it->path().string(), true);
}
h128 SecretStore::readKey(string const& _file, bool _takeFileOwnership)
{
cnote << "Reading" << _file;
return readKeyContent(contentsString(_file), _takeFileOwnership ? _file : string());
}
h128 SecretStore::readKeyContent(string const& _content, string const& _file)
{
js::mValue u = upgraded(_content);
if (u.type() == js::obj_type)
{
js::mObject& o = u.get_obj();
auto uuid = fromUUID(o["id"].get_str());
m_keys[uuid] = EncryptedKey{js::write_string(o["crypto"], false), _file};
return uuid;
}
else
cwarn << "Invalid JSON in key file" << _file;
return h128();
}
bool SecretStore::recode(h128 const& _uuid, string const& _newPass, function<string()> const& _pass, KDF _kdf)
{
bytesSec s = secret(_uuid, _pass, true);
if (s.empty())
return false;
m_cached.erase(_uuid);
m_keys[_uuid].encryptedKey = encrypt(s.ref(), _newPass, _kdf);
save();
return true;
}
static bytesSec deriveNewKey(string const& _pass, KDF _kdf, js::mObject& o_ret)
{
unsigned dklen = 32;
unsigned iterations = 1 << 18;
bytes salt = h256::random().asBytes();
if (_kdf == KDF::Scrypt)
{
unsigned p = 1;
unsigned r = 8;
o_ret["kdf"] = "scrypt";
{
js::mObject params;
params["n"] = int64_t(iterations);
params["r"] = int(r);
params["p"] = int(p);
params["dklen"] = int(dklen);
params["salt"] = toHex(salt);
o_ret["kdfparams"] = params;
}
return scrypt(_pass, salt, iterations, r, p, dklen);
}
else
{
o_ret["kdf"] = "pbkdf2";
{
js::mObject params;
params["prf"] = "hmac-sha256";
params["c"] = int(iterations);
params["salt"] = toHex(salt);
params["dklen"] = int(dklen);
o_ret["kdfparams"] = params;
}
return pbkdf2(_pass, salt, iterations, dklen);
}
}
string SecretStore::encrypt(bytesConstRef _v, string const& _pass, KDF _kdf)
{
js::mObject ret;
bytesSec derivedKey = deriveNewKey(_pass, _kdf, ret);
if (derivedKey.empty())
BOOST_THROW_EXCEPTION(crypto::CryptoException() << errinfo_comment("Key derivation failed."));
ret["cipher"] = "aes-128-ctr";
SecureFixedHash<16> key(derivedKey, h128::AlignLeft);
h128 iv = h128::random();
{
js::mObject params;
params["iv"] = toHex(iv.ref());
ret["cipherparams"] = params;
}
// cipher text
bytes cipherText = encryptSymNoAuth(key, iv, _v);
if (cipherText.empty())
BOOST_THROW_EXCEPTION(crypto::CryptoException() << errinfo_comment("Key encryption failed."));
ret["ciphertext"] = toHex(cipherText);
// and mac.
h256 mac = sha3(derivedKey.ref().cropped(16, 16).toBytes() + cipherText);
ret["mac"] = toHex(mac.ref());
return js::write_string(js::mValue(ret), true);
}
bytesSec SecretStore::decrypt(string const& _v, string const& _pass)
{
js::mObject o;
{
js::mValue ov;
js::read_string(_v, ov);
o = ov.get_obj();
}
// derive key
bytesSec derivedKey;
if (o["kdf"].get_str() == "pbkdf2")
{
auto params = o["kdfparams"].get_obj();
if (params["prf"].get_str() != "hmac-sha256")
{
cwarn << "Unknown PRF for PBKDF2" << params["prf"].get_str() << "not supported.";
return bytesSec();
}
unsigned iterations = params["c"].get_int();
bytes salt = fromHex(params["salt"].get_str());
derivedKey = pbkdf2(_pass, salt, iterations, params["dklen"].get_int());
}
else if (o["kdf"].get_str() == "scrypt")
{
auto p = o["kdfparams"].get_obj();
derivedKey = scrypt(_pass, fromHex(p["salt"].get_str()), p["n"].get_int(), p["r"].get_int(), p["p"].get_int(), p["dklen"].get_int());
}
else
{
cwarn << "Unknown KDF" << o["kdf"].get_str() << "not supported.";
return bytesSec();
}
if (derivedKey.size() < 32 && !(o.count("compat") && o["compat"].get_str() == "2"))
{
cwarn << "Derived key's length too short (<32 bytes)";
return bytesSec();
}
bytes cipherText = fromHex(o["ciphertext"].get_str());
// check MAC
if (o.count("mac"))
{
h256 mac(o["mac"].get_str());
h256 macExp;
if (o.count("compat") && o["compat"].get_str() == "2")
macExp = sha3(derivedKey.ref().cropped(derivedKey.size() - 16).toBytes() + cipherText);
else
macExp = sha3(derivedKey.ref().cropped(16, 16).toBytes() + cipherText);
if (mac != macExp)
{
cwarn << "Invalid key - MAC mismatch; expected" << toString(macExp) << ", got" << toString(mac);
return bytesSec();
}
}
else if (o.count("sillymac"))
{
h256 mac(o["sillymac"].get_str());
h256 macExp = sha3(asBytes(o["sillymacjson"].get_str()) + derivedKey.ref().cropped(derivedKey.size() - 16).toBytes() + cipherText);
if (mac != macExp)
{
cwarn << "Invalid key - MAC mismatch; expected" << toString(macExp) << ", got" << toString(mac);
return bytesSec();
}
}
else
cwarn << "No MAC. Proceeding anyway.";
// decrypt
if (o["cipher"].get_str() == "aes-128-ctr")
{
auto params = o["cipherparams"].get_obj();
h128 iv(params["iv"].get_str());
if (o.count("compat") && o["compat"].get_str() == "2")
{
SecureFixedHash<16> key(sha3Secure(derivedKey.ref().cropped(derivedKey.size() - 16)), h128::AlignRight);
return decryptSymNoAuth(key, iv, &cipherText);
}
else
return decryptSymNoAuth(SecureFixedHash<16>(derivedKey, h128::AlignLeft), iv, &cipherText);
}
else
{
cwarn << "Unknown cipher" << o["cipher"].get_str() << "not supported.";
return bytesSec();
}
}