Code:
/ FXUpdate3074 / FXUpdate3074 / 1.1 / untmp / whidbey / QFE / ndp / fx / src / xsp / System / Web / ImpersonationContext.cs / 4 / ImpersonationContext.cs
//------------------------------------------------------------------------------ //// Copyright (c) Microsoft Corporation. All rights reserved. // //----------------------------------------------------------------------------- namespace System.Web { using System; using System.Runtime.InteropServices; using System.Security.Permissions; using System.Web.Configuration; using System.Web.Hosting; using System.Web.Util; internal class ImpersonationContext : IDisposable { private HandleRef _savedToken; private bool _reverted; private bool _impersonating; // arg-less ctor creates dummy context internal ImpersonationContext() { } // ctor that takes a token impersonates that token internal ImpersonationContext(IntPtr token) { ImpersonateToken(new HandleRef(this, token)); } // IDisposable pattern ~ImpersonationContext() { Dispose(false); } void IDisposable.Dispose() { Undo(); } private void Dispose(bool disposing) { if (_savedToken.Handle != IntPtr.Zero) { try {} finally { UnsafeNativeMethods.CloseHandle(_savedToken.Handle); _savedToken = new HandleRef(this, IntPtr.Zero); } } } // impersonate a given token protected void ImpersonateToken(HandleRef token) { try { // first revert _savedToken = new HandleRef(this, GetCurrentToken()); if (_savedToken.Handle != IntPtr.Zero) { if (UnsafeNativeMethods.RevertToSelf() != 0) { _reverted = true; } } // impersonate token if not zero if (token.Handle != IntPtr.Zero) { if (UnsafeNativeMethods.SetThreadToken(IntPtr.Zero, token.Handle) == 0) { throw new HttpException(SR.GetString(SR.Cannot_impersonate)); } _impersonating = true; } } catch { RestoreImpersonation(); throw; } } // restore impersonation to the original state private void RestoreImpersonation() { // first revert before reimpersonating if (_impersonating) { UnsafeNativeMethods.RevertToSelf(); _impersonating = false; } // second reimpersonate the orignal saved identity (if exists) if (_savedToken.Handle != IntPtr.Zero) { if (_reverted) { if (UnsafeNativeMethods.SetThreadToken(IntPtr.Zero, _savedToken.Handle) == 0) { throw new HttpException(SR.GetString(SR.Cannot_impersonate)); } } _reverted = false; } } // 'public' version of Dispose internal void Undo() { RestoreImpersonation(); // free unmanaged resources Dispose(true); System.GC.SuppressFinalize(this); } // helper to get the currently impersonated token private static IntPtr GetCurrentToken() { IntPtr token = IntPtr.Zero; if (UnsafeNativeMethods.OpenThreadToken( UnsafeNativeMethods.GetCurrentThread(), UnsafeNativeMethods.TOKEN_READ | UnsafeNativeMethods.TOKEN_IMPERSONATE, true, ref token) == 0) { // if the last error is ERROR_NO_TOKEN it is ok, otherwise throw if (Marshal.GetLastWin32Error() != UnsafeNativeMethods.ERROR_NO_TOKEN) { throw new HttpException(SR.GetString(SR.Cannot_impersonate)); } } return token; } // helper to internal static bool CurrentThreadTokenExists { get { bool impersonating = false; try {} finally { IntPtr token = GetCurrentToken(); if (token != IntPtr.Zero) { impersonating = true; UnsafeNativeMethods.CloseHandle(token); } } return impersonating; } } } internal sealed class ProcessImpersonationContext : ImpersonationContext { internal ProcessImpersonationContext() { ImpersonateToken(new HandleRef(this, IntPtr.Zero)); } } internal sealed class ApplicationImpersonationContext : ImpersonationContext { internal ApplicationImpersonationContext() { ImpersonateToken(new HandleRef(this, HostingEnvironment.ApplicationIdentityToken)); } } internal sealed class ClientImpersonationContext : ImpersonationContext { internal ClientImpersonationContext(HttpContext context) { Start(context, true); } internal ClientImpersonationContext(HttpContext context, bool throwOnError) { Start(context, throwOnError); } private void Start(HttpContext context, bool throwOnError) { IntPtr token = IntPtr.Zero; try { if (context != null) { token = context.ImpersonationToken; } else { // by default use app identity token = HostingEnvironment.ApplicationIdentityToken; } } catch { if (throwOnError) { throw; } } // only impersonate if there is a token // this is to optimize for the default case of impersonation="false" // and no UNC identity, when requests run under process identity if (token != IntPtr.Zero) { ImpersonateToken(new HandleRef(this, token)); } } } } // File provided for Reference Use Only by Microsoft Corporation (c) 2007. // Copyright (c) Microsoft Corporation. All rights reserved.
Link Menu
This book is available now!
Buy at Amazon US or
Buy at Amazon UK
- XmlBinaryReader.cs
- BitmapInitialize.cs
- altserialization.cs
- CompositionDesigner.cs
- DataRecordInternal.cs
- TextFormatterHost.cs
- AssemblyName.cs
- SocketPermission.cs
- Cursors.cs
- HwndAppCommandInputProvider.cs
- _ConnectionGroup.cs
- TransactionFormatter.cs
- basecomparevalidator.cs
- GroupLabel.cs
- RangeBaseAutomationPeer.cs
- HttpProxyCredentialType.cs
- WmlTextBoxAdapter.cs
- CompModSwitches.cs
- ExternalException.cs
- ButtonChrome.cs
- UpdateProgress.cs
- StorageMappingItemLoader.cs
- BroadcastEventHelper.cs
- HttpCapabilitiesEvaluator.cs
- ServiceDescriptions.cs
- ReadOnlyCollection.cs
- ToolStripDropDownClosedEventArgs.cs
- EntityDataSourceUtil.cs
- DataGridViewComponentPropertyGridSite.cs
- NumberSubstitution.cs
- UpdateTranslator.cs
- PersonalizationProviderHelper.cs
- RegionData.cs
- XNodeNavigator.cs
- HttpDictionary.cs
- XmlQualifiedName.cs
- DataTemplateKey.cs
- CodeBlockBuilder.cs
- CreateUserWizardDesigner.cs
- BindingExpression.cs
- EventWaitHandle.cs
- PassportAuthenticationModule.cs
- WindowsListBox.cs
- BitmapPalette.cs
- AsyncStreamReader.cs
- XmlCDATASection.cs
- RuntimeCompatibilityAttribute.cs
- TextEncodedRawTextWriter.cs
- ISAPIWorkerRequest.cs
- SignerInfo.cs
- PathBox.cs
- LinqDataSourceValidationException.cs
- WebSysDescriptionAttribute.cs
- StateManagedCollection.cs
- PropertyMetadata.cs
- ArrayEditor.cs
- AutomationIdentifierGuids.cs
- HwndTarget.cs
- PeerInvitationResponse.cs
- ParserExtension.cs
- XMLSyntaxException.cs
- ColumnMapVisitor.cs
- AssemblyResolver.cs
- CodeExporter.cs
- Application.cs
- WebPartVerbsEventArgs.cs
- DefaultProxySection.cs
- SoapTypeAttribute.cs
- OverlappedAsyncResult.cs
- WindowsSysHeader.cs
- HitTestResult.cs
- EndPoint.cs
- ScrollItemProviderWrapper.cs
- FieldAccessException.cs
- XPathBinder.cs
- DbProviderFactory.cs
- CollectionChangeEventArgs.cs
- SqlProfileProvider.cs
- UniqueSet.cs
- CodeSubDirectory.cs
- WriteableBitmap.cs
- UTF8Encoding.cs
- SiteMapDataSource.cs
- BindToObject.cs
- PageParser.cs
- TabControl.cs
- VisualTreeFlattener.cs
- PersistenceTypeAttribute.cs
- ResourceWriter.cs
- AppDomainResourcePerfCounters.cs
- CodeArrayCreateExpression.cs
- QilGeneratorEnv.cs
- FieldBuilder.cs
- XmlReflectionMember.cs
- SerializationSectionGroup.cs
- ServerType.cs
- ObjectListField.cs
- SByteStorage.cs
- WebPartCloseVerb.cs
- HandleCollector.cs