Code:
/ FX-1434 / FX-1434 / 1.0 / untmp / whidbey / REDBITS / ndp / fx / src / xsp / System / Web / ImpersonationContext.cs / 2 / 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 check if there is a current token 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)); } } } }
Link Menu
This book is available now!
Buy at Amazon US or
Buy at Amazon UK
- SafePEFileHandle.cs
- ConditionChanges.cs
- Wizard.cs
- SolidColorBrush.cs
- KnownTypeAttribute.cs
- HttpConfigurationContext.cs
- BaseCollection.cs
- ClientSettingsSection.cs
- EpmCustomContentDeSerializer.cs
- IsolatedStorage.cs
- KoreanLunisolarCalendar.cs
- StructuredProperty.cs
- SchemaImporterExtensionElementCollection.cs
- EntityReference.cs
- ContentOperations.cs
- SystemIPGlobalProperties.cs
- XmlWhitespace.cs
- mediaeventshelper.cs
- CharEntityEncoderFallback.cs
- Win32KeyboardDevice.cs
- SystemColorTracker.cs
- OraclePermission.cs
- TextEmbeddedObject.cs
- SplitContainer.cs
- SpeechDetectedEventArgs.cs
- APCustomTypeDescriptor.cs
- LeftCellWrapper.cs
- LocalizationParserHooks.cs
- Certificate.cs
- CustomAttribute.cs
- ObjectViewFactory.cs
- StatusInfoItem.cs
- NameSpaceExtractor.cs
- XmlLanguage.cs
- Scripts.cs
- StatusBarDrawItemEvent.cs
- MenuItem.cs
- CellQuery.cs
- GAC.cs
- ScalarRestriction.cs
- HandleInitializationContext.cs
- TreeNodeBindingDepthConverter.cs
- PersistenceContext.cs
- WindowsFormsHelpers.cs
- CompilerGeneratedAttribute.cs
- TextBoxLine.cs
- ContentControl.cs
- Encoder.cs
- WebServiceHandler.cs
- SortFieldComparer.cs
- AsmxEndpointPickerExtension.cs
- ExpandCollapseProviderWrapper.cs
- GlobalizationSection.cs
- SyndicationElementExtension.cs
- AlignmentYValidation.cs
- ListViewInsertionMark.cs
- URLString.cs
- PanelStyle.cs
- XsdValidatingReader.cs
- SiteMembershipCondition.cs
- CollectionMarkupSerializer.cs
- StringSource.cs
- DisplayNameAttribute.cs
- FontSource.cs
- TreeNodeConverter.cs
- WebControlParameterProxy.cs
- PlanCompiler.cs
- OAVariantLib.cs
- _DynamicWinsockMethods.cs
- TextEditor.cs
- ScrollData.cs
- TracedNativeMethods.cs
- Converter.cs
- XmlSchemaSimpleTypeUnion.cs
- ExecutionScope.cs
- CanExecuteRoutedEventArgs.cs
- DocumentStream.cs
- EdmError.cs
- DefaultMemberAttribute.cs
- QilStrConcat.cs
- PrimitiveSchema.cs
- CounterSetInstance.cs
- RoleManagerEventArgs.cs
- ObjectDataSourceView.cs
- Listen.cs
- TypeTypeConverter.cs
- ViewBase.cs
- MethodBody.cs
- CryptoStream.cs
- ServiceBuildProvider.cs
- TraceFilter.cs
- XmlComment.cs
- PerformanceCounterPermission.cs
- RecordsAffectedEventArgs.cs
- ParameterElementCollection.cs
- TimeSpanConverter.cs
- DataSpaceManager.cs
- SQLRoleProvider.cs
- StylusButton.cs
- FrameworkReadOnlyPropertyMetadata.cs