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//
// ProtectedMemory.cs: Protect (encrypt) memory without (user involved) key management
//
// Author:
// Sebastien Pouliot <sebastien@ximian.com>
//
// (C) 2003 Motus Technologies Inc. (http://www.motus.com)
// Copyright (C) 2004-2005 Novell, Inc (http://www.novell.com)
//
// Permission is hereby granted, free of charge, to any person obtaining
// a copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to
// permit persons to whom the Software is furnished to do so, subject to
// the following conditions:
//
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//
using System.Runtime.InteropServices;
using System.Security;
using System.Security.Permissions;
namespace System.Security.Cryptography {
// References:
// a. Windows Data Protection
// http://msdn.microsoft.com/library/en-us/dnsecure/html/windataprotection-dpapi.asp?frame=true
public sealed class ProtectedMemory {
private ProtectedMemory ()
{
}
[MonoTODO ("only supported on Windows 2000 SP3 and later")]
// FIXME [DataProtectionPermission (SecurityAction.Demand, ProtectMemory = true)]
public static void Protect (byte[] userData, MemoryProtectionScope scope)
{
if (userData == null)
throw new ArgumentNullException ("userData");
Check (userData.Length, scope);
try {
uint flags = (uint) scope;
uint length = (uint) userData.Length;
switch (impl) {
case MemoryProtectionImplementation.Win32RtlEncryptMemory:
int err = RtlEncryptMemory (userData, length, flags);
if (err < 0) {
string msg = Locale.GetText ("Error. NTSTATUS = {0}.", err);
throw new CryptographicException (msg);
}
break;
case MemoryProtectionImplementation.Win32CryptoProtect:
bool result = CryptProtectMemory (userData, length, flags);
if (!result)
throw new CryptographicException (Marshal.GetLastWin32Error ());
break;
default:
throw new PlatformNotSupportedException ();
}
}
catch {
// Windows 2000 before SP3 will throw
impl = MemoryProtectionImplementation.Unsupported;
throw new PlatformNotSupportedException ();
}
}
[MonoTODO ("only supported on Windows 2000 SP3 and later")]
// FIXME [DataProtectionPermission (SecurityAction.Demand, UnprotectMemory = true)]
public static void Unprotect (byte[] encryptedData, MemoryProtectionScope scope)
{
if (encryptedData == null)
throw new ArgumentNullException ("encryptedData");
Check (encryptedData.Length, scope);
try {
uint flags = (uint) scope;
uint length = (uint) encryptedData.Length;
switch (impl) {
case MemoryProtectionImplementation.Win32RtlEncryptMemory:
int err = RtlDecryptMemory (encryptedData, length, flags);
if (err < 0) {
string msg = Locale.GetText ("Error. NTSTATUS = {0}.", err);
throw new CryptographicException (msg);
}
break;
case MemoryProtectionImplementation.Win32CryptoProtect:
bool result = CryptUnprotectMemory (encryptedData, length, flags);
if (!result)
throw new CryptographicException (Marshal.GetLastWin32Error ());
break;
default:
throw new PlatformNotSupportedException ();
}
}
catch {
// Windows 2000 before SP3 will throw
impl = MemoryProtectionImplementation.Unsupported;
throw new PlatformNotSupportedException ();
}
}
// private stuff
private const int BlockSize = 16;
enum MemoryProtectionImplementation {
Unknown,
Win32RtlEncryptMemory,
Win32CryptoProtect,
Unsupported = Int32.MinValue
}
private static MemoryProtectionImplementation impl;
private static void Detect ()
{
OperatingSystem os = Environment.OSVersion;
switch (os.Platform) {
case PlatformID.Win32NT:
Version v = os.Version;
if (v.Major < 5) {
impl = MemoryProtectionImplementation.Unsupported;
} else if (v.Major == 5) {
if (v.Minor < 2) {
// 2000 (5.0) Service Pack 3 and XP (5.1)
impl = MemoryProtectionImplementation.Win32RtlEncryptMemory;
} else {
impl = MemoryProtectionImplementation.Win32CryptoProtect;
}
} else {
// vista (6.0) and later
impl = MemoryProtectionImplementation.Win32CryptoProtect;
}
break;
default:
impl = MemoryProtectionImplementation.Unsupported;
break;
}
}
private static void Check (int size, MemoryProtectionScope scope)
{
if (size % BlockSize != 0) {
string msg = Locale.GetText ("Not a multiple of {0} bytes.", BlockSize);
throw new CryptographicException (msg);
}
if ((scope < MemoryProtectionScope.SameProcess) || (scope > MemoryProtectionScope.SameLogon)) {
string msg = Locale.GetText ("Invalid enum value for '{0}'.", "MemoryProtectionScope");
throw new ArgumentException (msg, "scope");
}
switch (impl) {
case MemoryProtectionImplementation.Unknown:
Detect ();
break;
case MemoryProtectionImplementation.Unsupported:
throw new PlatformNotSupportedException ();
}
}
// http://msdn.microsoft.com/library/en-us/dncode/html/secure06122003.asp
// Summary: CryptProtectMemory and CryptUnprotectMemory exists only in Windows 2003 +
// but they are available in advapi32.dll as RtlEncryptMemory (SystemFunction040) and
// RtlDecryptMemory (SystemFunction041) since Windows 2000 SP 3. Sadly both can disappear
// anytime with newer OS so we include support for Crypt[Unp|P]rotectMemory too.
[SuppressUnmanagedCodeSecurity]
[DllImport ("advapi32.dll", EntryPoint="SystemFunction040", SetLastError = true, CallingConvention = CallingConvention.StdCall, CharSet = CharSet.Auto)]
private static extern int RtlEncryptMemory (byte[] pData, uint cbData, uint dwFlags);
[SuppressUnmanagedCodeSecurity]
[DllImport ("advapi32.dll", EntryPoint = "SystemFunction041", SetLastError = true, CallingConvention = CallingConvention.StdCall, CharSet = CharSet.Auto)]
private static extern int RtlDecryptMemory (byte[] pData, uint cbData, uint dwFlags);
[SuppressUnmanagedCodeSecurity]
[DllImport ("crypt32.dll", SetLastError = true, CallingConvention = CallingConvention.StdCall, CharSet = CharSet.Auto)]
private static extern bool CryptProtectMemory (byte[] pData, uint cbData, uint dwFlags);
[SuppressUnmanagedCodeSecurity]
[DllImport ("crypt32.dll", SetLastError = true, CallingConvention = CallingConvention.StdCall, CharSet = CharSet.Auto)]
private static extern bool CryptUnprotectMemory (byte[] pData, uint cbData, uint dwFlags);
}
}