235 lines
6.8 KiB
C#
235 lines
6.8 KiB
C#
/*
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KeePass Password Safe - The Open-Source Password Manager
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Copyright (C) 2003-2012 Dominik Reichl <dominik.reichl@t-online.de>
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Modified to be used with Mono for Android. Changes Copyright (C) 2013 Philipp Crocoll
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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using System;
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using System.Security.Cryptography;
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using System.Diagnostics;
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using KeePassLib.Cryptography;
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using KeePassLib.Utility;
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#if KeePassLibSD
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using KeePassLibSD;
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#endif
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namespace KeePassLib.Security
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{
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/// <summary>
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/// Represents a protected binary, i.e. a byte array that is encrypted
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/// in memory. A <c>ProtectedBinary</c> object is immutable and
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/// thread-safe.
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/// </summary>
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public sealed class ProtectedBinary : IEquatable<ProtectedBinary>
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{
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private const int PmBlockSize = 16;
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// In-memory protection is supported only on Windows 2000 SP3 and
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// higher.
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private static bool m_bProtectionSupported;
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private byte[] m_pbData; // Never null
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// The real length of the data. This value can be different than
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// m_pbData.Length, as the length of m_pbData always is a multiple
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// of PmBlockSize (required for fast in-memory protection).
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private uint m_uDataLen;
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private bool m_bProtected;
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private object m_objSync = new object();
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/// <summary>
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/// A flag specifying whether the <c>ProtectedBinary</c> object has
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/// turned on in-memory protection or not.
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/// </summary>
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public bool IsProtected
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{
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get { return m_bProtected; }
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}
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/// <summary>
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/// Length of the stored data.
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/// </summary>
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public uint Length
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{
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get { return m_uDataLen; }
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}
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static ProtectedBinary()
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{
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//protection not supported on Android currently
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m_bProtectionSupported = false;
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}
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/// <summary>
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/// Construct a new, empty protected binary data object. Protection
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/// is disabled.
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/// </summary>
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public ProtectedBinary()
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{
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Init(false, new byte[0]);
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}
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/// <summary>
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/// Construct a new protected binary data object.
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/// </summary>
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/// <param name="bEnableProtection">If this paremeter is <c>true</c>,
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/// the data will be encrypted in memory. If it is <c>false</c>, the
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/// data is stored in plain-text in the process memory.</param>
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/// <param name="pbData">Value of the protected object.
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/// The input parameter is not modified and
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/// <c>ProtectedBinary</c> doesn't take ownership of the data,
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/// i.e. the caller is responsible for clearing it.</param>
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public ProtectedBinary(bool bEnableProtection, byte[] pbData)
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{
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Init(bEnableProtection, pbData);
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}
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/// <summary>
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/// Construct a new protected binary data object. Copy the data from
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/// a <c>XorredBuffer</c> object.
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/// </summary>
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/// <param name="bEnableProtection">Enable protection or not.</param>
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/// <param name="xbProtected"><c>XorredBuffer</c> object used to
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/// initialize the <c>ProtectedBinary</c> object.</param>
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/// <exception cref="System.ArgumentNullException">Thrown if the input
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/// parameter is <c>null</c>.</exception>
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public ProtectedBinary(bool bEnableProtection, XorredBuffer xbProtected)
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{
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Debug.Assert(xbProtected != null); if(xbProtected == null) throw new ArgumentNullException("xbProtected");
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byte[] pb = xbProtected.ReadPlainText();
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Init(bEnableProtection, pb);
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MemUtil.ZeroByteArray(pb);
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}
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private void Init(bool bEnableProtection, byte[] pbData)
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{
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if(pbData == null) throw new ArgumentNullException("pbData");
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m_bProtected = bEnableProtection;
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m_uDataLen = (uint)pbData.Length;
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int nBlocks = (int)m_uDataLen / PmBlockSize;
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if((nBlocks * PmBlockSize) < (int)m_uDataLen) ++nBlocks;
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Debug.Assert((nBlocks * PmBlockSize) >= (int)m_uDataLen);
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m_pbData = new byte[nBlocks * PmBlockSize];
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Array.Copy(pbData, m_pbData, (int)m_uDataLen);
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// Data size must be > 0, otherwise 'Protect' throws
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if(m_bProtected && m_bProtectionSupported && (m_uDataLen > 0))
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throw new NotSupportedException();
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}
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/// <summary>
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/// Get a copy of the protected data as a byte array.
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/// Please note that the returned byte array is not protected and
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/// can therefore been read by any other application.
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/// Make sure that your clear it properly after usage.
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/// </summary>
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/// <returns>Unprotected byte array. This is always a copy of the internal
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/// protected data and can therefore be cleared safely.</returns>
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public byte[] ReadData()
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{
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if(m_uDataLen == 0) return new byte[0];
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byte[] pbReturn = new byte[m_uDataLen];
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if(m_bProtected && m_bProtectionSupported)
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{
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lock(m_objSync)
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{
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throw new NotSupportedException();
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}
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}
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else Array.Copy(m_pbData, pbReturn, (int)m_uDataLen);
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return pbReturn;
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}
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/// <summary>
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/// Read the protected data and return it protected with a sequence
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/// of bytes generated by a random stream.
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/// </summary>
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/// <param name="crsRandomSource">Random number source.</param>
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/// <returns>Protected data.</returns>
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/// <exception cref="System.ArgumentNullException">Thrown if the input
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/// parameter is <c>null</c>.</exception>
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public byte[] ReadXorredData(CryptoRandomStream crsRandomSource)
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{
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Debug.Assert(crsRandomSource != null);
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if(crsRandomSource == null) throw new ArgumentNullException("crsRandomSource");
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byte[] pbData = ReadData();
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uint uLen = (uint)pbData.Length;
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byte[] randomPad = crsRandomSource.GetRandomBytes(uLen);
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Debug.Assert(randomPad.Length == uLen);
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for(uint i = 0; i < uLen; ++i)
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pbData[i] ^= randomPad[i];
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return pbData;
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}
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public override int GetHashCode()
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{
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int h = (m_bProtected ? 0x7B11D289 : 0);
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byte[] pb = ReadData();
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unchecked
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{
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for(int i = 0; i < pb.Length; ++i)
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h = (h << 3) + h + (int)pb[i];
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}
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MemUtil.ZeroByteArray(pb);
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return h;
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}
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public override bool Equals(object obj)
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{
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return Equals(obj as ProtectedBinary);
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}
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public bool Equals(ProtectedBinary other)
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{
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if(other == null) return false; // No assert
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if(m_bProtected != other.m_bProtected) return false;
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if(m_uDataLen != other.m_uDataLen) return false;
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byte[] pbL = ReadData();
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byte[] pbR = other.ReadData();
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bool bEq = MemUtil.ArraysEqual(pbL, pbR);
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MemUtil.ZeroByteArray(pbL);
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MemUtil.ZeroByteArray(pbR);
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#if DEBUG
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if(bEq) { Debug.Assert(GetHashCode() == other.GetHashCode()); }
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#endif
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return bEq;
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}
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}
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}
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