Apply PBKDF2 when storing passwords

src/base/utils/password.cpp

@@ -0,0 +1,120 @@
+/*
+ * Bittorrent Client using Qt and libtorrent.
+ * Copyright (C) 2018  Mike Tzou (Chocobo1)
+ *
+ * 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.
+ *
+ * In addition, as a special exception, the copyright holders give permission to
+ * link this program with the OpenSSL project's "OpenSSL" library (or with
+ * modified versions of it that use the same license as the "OpenSSL" library),
+ * and distribute the linked executables. You must obey the GNU General Public
+ * License in all respects for all of the code used other than "OpenSSL".  If you
+ * modify file(s), you may extend this exception to your version of the file(s),
+ * but you are not obligated to do so. If you do not wish to do so, delete this
+ * exception statement from your version.
+ */
+
+#include "password.h"
+
+#include <array>
+
+#include <openssl/evp.h>
+
+#include <QByteArray>
+#include <QList>
+#include <QString>
+
+#include "bytearray.h"
+#include "random.h"
+#include "string.h"
+
+namespace Utils
+{
+    namespace Password
+    {
+        namespace PBKDF2
+        {
+            const int hashIterations = 100000;
+            const auto hashMethod = EVP_sha512();
+        }
+    }
+}
+
+// Implements constant-time comparison to protect against timing attacks
+// Taken from https://crackstation.net/hashing-security.htm
+bool Utils::Password::slowEquals(const QByteArray &a, const QByteArray &b)
+{
+    const int lengthA = a.length();
+    const int lengthB = b.length();
+
+    int diff = lengthA ^ lengthB;
+    for (int i = 0; (i < lengthA) && (i < lengthB); ++i)
+        diff |= a[i] ^ b[i];
+
+    return (diff == 0);
+}
+
+QByteArray Utils::Password::PBKDF2::generate(const QString &password)
+{
+    return generate(password.toUtf8());
+}
+
+QByteArray Utils::Password::PBKDF2::generate(const QByteArray &password)
+{
+    const std::array<uint32_t, 4> salt {{Random::rand(), Random::rand()
+        , Random::rand(), Random::rand()}};
+
+    std::array<unsigned char, 64> outBuf {};
+    const int hmacResult = PKCS5_PBKDF2_HMAC(password.constData(), password.size()
+        , reinterpret_cast<const unsigned char *>(salt.data()), (sizeof(salt[0]) * salt.size())
+        , hashIterations, hashMethod
+        , outBuf.size(), outBuf.data());
+    if (hmacResult != 1)
+        return {};
+
+    const QByteArray saltView = QByteArray::fromRawData(
+        reinterpret_cast<const char *>(salt.data()), (sizeof(salt[0]) * salt.size()));
+    const QByteArray outBufView = QByteArray::fromRawData(
+        reinterpret_cast<const char *>(outBuf.data()), outBuf.size());
+
+    return (saltView.toBase64() + ':' + outBufView.toBase64());
+}
+
+bool Utils::Password::PBKDF2::verify(const QByteArray &secret, const QString &password)
+{
+    return verify(secret, password.toUtf8());
+}
+
+bool Utils::Password::PBKDF2::verify(const QByteArray &secret, const QByteArray &password)
+{
+    const QList<QByteArray> list = ByteArray::splitToViews(secret, ":", QString::SkipEmptyParts);
+    if (list.size() != 2)
+        return false;
+
+    const QByteArray salt = QByteArray::fromBase64(list[0]);
+    const QByteArray key = QByteArray::fromBase64(list[1]);
+
+    std::array<unsigned char, 64> outBuf {};
+    const int hmacResult = PKCS5_PBKDF2_HMAC(password.constData(), password.size()
+        , reinterpret_cast<const unsigned char *>(salt.constData()), salt.size()
+        , hashIterations, hashMethod
+        , outBuf.size(), outBuf.data());
+    if (hmacResult != 1)
+        return false;
+
+    const QByteArray outBufView = QByteArray::fromRawData(
+        reinterpret_cast<const char *>(outBuf.data()), outBuf.size());
+    return slowEquals(key, outBufView);
+}