Setup solution

ModernKeePassLib/Cryptography/PasswordGenerator/PwGenerator.cs

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+/*
+  KeePass Password Safe - The Open-Source Password Manager
+  Copyright (C) 2003-2019 Dominik Reichl <dominik.reichl@t-online.de>
+
+  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 St, Fifth Floor, Boston, MA  02110-1301  USA
+*/
+
+using System;
+using System.Collections.Generic;
+using System.Diagnostics;
+using System.Text;
+
+#if !KeePassUAP
+using System.Security.Cryptography;
+#endif
+
+using ModernKeePassLib.Security;
+using ModernKeePassLib.Utility;
+
+namespace ModernKeePassLib.Cryptography.PasswordGenerator
+{
+	public enum PwgError
+	{
+		Success = 0,
+		Unknown = 1,
+		TooFewCharacters = 2,
+		UnknownAlgorithm = 3
+	}
+
+	/// <summary>
+	/// Utility functions for generating random passwords.
+	/// </summary>
+	public static class PwGenerator
+	{
+		public static PwgError Generate(out ProtectedString psOut,
+			PwProfile pwProfile, byte[] pbUserEntropy,
+			CustomPwGeneratorPool pwAlgorithmPool)
+		{
+			Debug.Assert(pwProfile != null);
+			if(pwProfile == null) throw new ArgumentNullException("pwProfile");
+
+			PwgError e = PwgError.Unknown;
+			CryptoRandomStream crs = null;
+			byte[] pbKey = null;
+			try
+			{
+				crs = CreateRandomStream(pbUserEntropy, out pbKey);
+
+				if(pwProfile.GeneratorType == PasswordGeneratorType.CharSet)
+					e = CharSetBasedGenerator.Generate(out psOut, pwProfile, crs);
+				else if(pwProfile.GeneratorType == PasswordGeneratorType.Pattern)
+					e = PatternBasedGenerator.Generate(out psOut, pwProfile, crs);
+				else if(pwProfile.GeneratorType == PasswordGeneratorType.Custom)
+					e = GenerateCustom(out psOut, pwProfile, crs, pwAlgorithmPool);
+				else { Debug.Assert(false); psOut = ProtectedString.Empty; }
+			}
+			finally
+			{
+				if(crs != null) crs.Dispose();
+				if(pbKey != null) MemUtil.ZeroByteArray(pbKey);
+			}
+
+			return e;
+		}
+
+		private static CryptoRandomStream CreateRandomStream(byte[] pbAdditionalEntropy,
+			out byte[] pbKey)
+		{
+			pbKey = CryptoRandom.Instance.GetRandomBytes(128);
+
+			// Mix in additional entropy
+			Debug.Assert(pbKey.Length >= 64);
+			if((pbAdditionalEntropy != null) && (pbAdditionalEntropy.Length > 0))
+			{
+				using(SHA512Managed h = new SHA512Managed())
+				{
+					byte[] pbHash = h.ComputeHash(pbAdditionalEntropy);
+					MemUtil.XorArray(pbHash, 0, pbKey, 0, pbHash.Length);
+				}
+			}
+
+			return new CryptoRandomStream(CrsAlgorithm.ChaCha20, pbKey);
+		}
+
+		internal static char GenerateCharacter(PwProfile pwProfile,
+			PwCharSet pwCharSet, CryptoRandomStream crsRandomSource)
+		{
+			if(pwCharSet.Size == 0) return char.MinValue;
+
+			ulong uIndex = crsRandomSource.GetRandomUInt64();
+			uIndex %= (ulong)pwCharSet.Size;
+
+			char ch = pwCharSet[(uint)uIndex];
+
+			if(pwProfile.NoRepeatingCharacters)
+				pwCharSet.Remove(ch);
+
+			return ch;
+		}
+
+		internal static void PrepareCharSet(PwCharSet pwCharSet, PwProfile pwProfile)
+		{
+			pwCharSet.Remove(PwCharSet.Invalid);
+
+			if(pwProfile.ExcludeLookAlike) pwCharSet.Remove(PwCharSet.LookAlike);
+
+			if(pwProfile.ExcludeCharacters.Length > 0)
+				pwCharSet.Remove(pwProfile.ExcludeCharacters);
+		}
+
+		internal static void Shuffle(char[] v, CryptoRandomStream crsRandomSource)
+		{
+			if(v == null) { Debug.Assert(false); return; }
+			if(crsRandomSource == null) { Debug.Assert(false); return; }
+
+			for(int i = v.Length - 1; i >= 1; --i)
+			{
+				ulong r = crsRandomSource.GetRandomUInt64();
+				int j = (int)(r % (ulong)(i + 1));
+
+				char t = v[i];
+				v[i] = v[j];
+				v[j] = t;
+			}
+		}
+
+		private static PwgError GenerateCustom(out ProtectedString psOut,
+			PwProfile pwProfile, CryptoRandomStream crs,
+			CustomPwGeneratorPool pwAlgorithmPool)
+		{
+			psOut = ProtectedString.Empty;
+
+			Debug.Assert(pwProfile.GeneratorType == PasswordGeneratorType.Custom);
+			if(pwAlgorithmPool == null) return PwgError.UnknownAlgorithm;
+
+			string strID = pwProfile.CustomAlgorithmUuid;
+			if(string.IsNullOrEmpty(strID)) return PwgError.UnknownAlgorithm;
+
+			byte[] pbUuid = Convert.FromBase64String(strID);
+			PwUuid uuid = new PwUuid(pbUuid);
+			CustomPwGenerator pwg = pwAlgorithmPool.Find(uuid);
+			if(pwg == null) { Debug.Assert(false); return PwgError.UnknownAlgorithm; }
+
+			ProtectedString pwd = pwg.Generate(pwProfile.CloneDeep(), crs);
+			if(pwd == null) return PwgError.Unknown;
+
+			psOut = pwd;
+			return PwgError.Success;
+		}
+	}
+}