class/corlib/System.Security/SecurityContext.cs

   1 //
   2 // System.Security.SecurityContext class
   3 //
   4 // Author:
   5 //      Sebastien Pouliot  <sebastien@ximian.com>
   6 //
   7 // Copyright (C) 2004-2005 Novell, Inc (http://www.novell.com)
   8 //
   9 // Permission is hereby granted, free of charge, to any person obtaining
  10 // a copy of this software and associated documentation files (the
  11 // "Software"), to deal in the Software without restriction, including
  12 // without limitation the rights to use, copy, modify, merge, publish,
  13 // distribute, sublicense, and/or sell copies of the Software, and to
  14 // permit persons to whom the Software is furnished to do so, subject to
  15 // the following conditions:
  16 //
  17 // The above copyright notice and this permission notice shall be
  18 // included in all copies or substantial portions of the Software.
  19 //
  20 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  21 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  22 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  23 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  24 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  25 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  26 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  27 //
  28
  29 using System.Runtime.InteropServices;
  30 using System.Security.Permissions;
  31 using System.Security.Principal;
  32 using System.Threading;
  33
  34 namespace System.Security {
  35
  36         public sealed class SecurityContext {
  37                 private bool _capture;
  38                 private IntPtr _winid;
  39                 private CompressedStack _stack;
  40                 private bool _suppressFlowWindowsIdentity;
  41                 private bool _suppressFlow;
  42
  43                 internal SecurityContext ()
  44                 {
  45                 }
  46
  47                 // copy constructor
  48                 internal SecurityContext (SecurityContext sc)
  49                 {
  50                         _capture = true;
  51                         _winid = sc._winid;
  52                         if (sc._stack != null)
  53                                 _stack = sc._stack.CreateCopy ();
  54                 }
  55
  56                 public SecurityContext CreateCopy ()
  57                 {
  58                         if (!_capture)
  59                                 throw new InvalidOperationException ();
  60
  61                         return new SecurityContext (this);
  62                 }
  63
  64                 // static methods
  65
  66                 static public SecurityContext Capture ()
  67                 {
  68                         SecurityContext sc = Thread.CurrentThread.ExecutionContext.SecurityContext;
  69                         if (sc.FlowSuppressed)
  70                                 return null;
  71
  72                         SecurityContext capture = new SecurityContext ();
  73                         capture._capture = true;
  74                         capture._winid = WindowsIdentity.GetCurrentToken ();
  75                         capture._stack = CompressedStack.Capture ();
  76                         return capture;
  77                 }
  78
  79                 // internal stuff
  80
  81                 internal bool FlowSuppressed {
  82                         get { return _suppressFlow; }
  83                         set { _suppressFlow = value; }
  84                 }
  85
  86                 internal bool WindowsIdentityFlowSuppressed {
  87                         get { return _suppressFlowWindowsIdentity; }
  88                         set { _suppressFlowWindowsIdentity = value; }
  89                 }
  90
  91                 internal CompressedStack CompressedStack {
  92                         get { return _stack; }
  93                         set { _stack = value; }
  94                 }
  95
  96                 internal IntPtr IdentityToken {
  97                         get { return _winid; }
  98                         set { _winid = value; }
  99                 }
 100
 101                 // Suppressing the SecurityContext flow wasn't required before 2.0
 102
 103                 static public bool IsFlowSuppressed ()
 104                 {
 105                         return Thread.CurrentThread.ExecutionContext.SecurityContext.FlowSuppressed;
 106                 }
 107
 108                 static public bool IsWindowsIdentityFlowSuppressed ()
 109                 {
 110                         return Thread.CurrentThread.ExecutionContext.SecurityContext.WindowsIdentityFlowSuppressed;
 111                 }
 112
 113                 static public void RestoreFlow ()
 114                 {
 115                         SecurityContext sc = Thread.CurrentThread.ExecutionContext.SecurityContext;
 116                         // if nothing is suppressed then throw
 117                         if (!sc.FlowSuppressed && !sc.WindowsIdentityFlowSuppressed)
 118                                 throw new InvalidOperationException ();
 119
 120                         sc.FlowSuppressed = false;
 121                         sc.WindowsIdentityFlowSuppressed = false;
 122                 }
 123
 124                 // if you got the context then you can use it
 125                 [SecurityPermission (SecurityAction.Assert, ControlPrincipal = true)]
 126                 [SecurityPermission (SecurityAction.LinkDemand, Infrastructure = true)]
 127                 static public void Run (SecurityContext securityContext, ContextCallback callback, object state)
 128                 {
 129                         if (securityContext == null) {
 130                                 throw new InvalidOperationException (Locale.GetText (
 131                                         "Null SecurityContext"));
 132                         }
 133
 134                         SecurityContext sc = Thread.CurrentThread.ExecutionContext.SecurityContext;
 135                         IPrincipal original = Thread.CurrentPrincipal;
 136                         try {
 137                                 if (sc.IdentityToken != IntPtr.Zero) {
 138                                         Thread.CurrentPrincipal = new WindowsPrincipal (new WindowsIdentity (sc.IdentityToken));
 139                                 }
 140
 141                                 // FIXME: is the security manager isn't active then we may not have
 142                                 // a compressed stack (bug #78652)
 143                                 if (securityContext.CompressedStack != null)
 144                                         CompressedStack.Run (securityContext.CompressedStack, callback, state);
 145                                 else
 146                                         callback (state);
 147                         }
 148                         finally {
 149                                 if ((original != null) && (sc.IdentityToken != IntPtr.Zero))
 150                                         Thread.CurrentPrincipal = original;
 151                         }
 152                 }
 153
 154                 [SecurityPermission (SecurityAction.LinkDemand, Infrastructure = true)]
 155                 static public AsyncFlowControl SuppressFlow ()
 156                 {
 157                         Thread t = Thread.CurrentThread;
 158                         // suppress both flows
 159                         t.ExecutionContext.SecurityContext.FlowSuppressed = true;
 160                         t.ExecutionContext.SecurityContext.WindowsIdentityFlowSuppressed = true;
 161                         return new AsyncFlowControl (t, AsyncFlowControlType.Security);
 162                 }
 163
 164                 static public AsyncFlowControl SuppressFlowWindowsIdentity ()
 165                 {
 166                         Thread t = Thread.CurrentThread;
 167                         t.ExecutionContext.SecurityContext.WindowsIdentityFlowSuppressed = true;
 168                         return new AsyncFlowControl (t, AsyncFlowControlType.Security);
 169                 }
 170         }
 171 }