class/corlib/System.Security.Permissions/UrlIdentityPermission.cs

   1 //
   2 // System.Security.Permissions.UrlIdentityPermission.cs
   3 //
   4 // Author
   5 //      Sebastien Pouliot  <sebastien@ximian.com>
   6 //
   7 // Copyright (C) 2003 Motus Technologies. http://www.motus.com
   8 // Copyright (C) 2004-2005 Novell, Inc (http://www.novell.com)
   9 //
  10 // Permission is hereby granted, free of charge, to any person obtaining
  11 // a copy of this software and associated documentation files (the
  12 // "Software"), to deal in the Software without restriction, including
  13 // without limitation the rights to use, copy, modify, merge, publish,
  14 // distribute, sublicense, and/or sell copies of the Software, and to
  15 // permit persons to whom the Software is furnished to do so, subject to
  16 // the following conditions:
  17 //
  18 // The above copyright notice and this permission notice shall be
  19 // included in all copies or substantial portions of the Software.
  20 //
  21 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  22 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  23 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  24 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  25 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  26 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  27 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  28 //
  29
  30 using System.Globalization;
  31 using System.Runtime.InteropServices;
  32
  33 namespace System.Security.Permissions {
  34
  35         [Serializable]
  36         [ComVisible (true)]
  37         public sealed class UrlIdentityPermission : CodeAccessPermission, IBuiltInPermission {
  38
  39                 private const int version = 1;
  40
  41                 private string url;
  42
  43                 public UrlIdentityPermission (PermissionState state)
  44                 {
  45                         // false == do not allow Unrestricted for Identity Permissions
  46                         CheckPermissionState (state, false);
  47                         url = String.Empty;
  48                 }
  49
  50                 public UrlIdentityPermission (string site)
  51                 {
  52                         if (site == null)
  53                                 throw new ArgumentNullException ("site");
  54                         url = site;
  55                 }
  56
  57                 public string Url {
  58                         get { return url; }
  59                         set { url = ((value == null) ? String.Empty : value); }
  60                 }
  61                 public override IPermission Copy ()
  62                 {
  63                         if (url == null) {
  64                                 return new UrlIdentityPermission (PermissionState.None);
  65                         }
  66                         else
  67                                 return new UrlIdentityPermission (url);
  68                 }
  69
  70                 public override void FromXml (SecurityElement esd)
  71                 {
  72                         // General validation in CodeAccessPermission
  73                         CheckSecurityElement (esd, "esd", 1, 1);
  74                         // Note: we do not (yet) care about the return value
  75                         // as we only accept version 1 (min/max values)
  76
  77                         string u = esd.Attribute ("Url");
  78                         if (u == null)
  79                                 url = String.Empty;
  80                         else
  81                                 Url = u;
  82                 }
  83
  84                 public override IPermission Intersect (IPermission target)
  85                 {
  86                         // if one permission is null (object or url) then there's no intersection
  87                         // if both are null then intersection is null
  88                         UrlIdentityPermission uip = Cast (target);
  89                         if ((uip == null) || (IsEmpty ()))
  90                                 return null;
  91                         if (Match (uip.url)) {
  92                                 // longest form is the intersection
  93                                 if (url.Length > uip.url.Length)
  94                                         return Copy ();
  95                                 else
  96                                         return uip.Copy ();
  97                         }
  98                         return null;
  99                 }
 100
 101                 public override bool IsSubsetOf (IPermission target)
 102                 {
 103                         UrlIdentityPermission uip = Cast (target);
 104                         if (uip == null)
 105                                 return IsEmpty ();
 106                         if (IsEmpty ())
 107                                 return true;
 108                         if (uip.url == null)
 109                                 return false;
 110
 111                         // here Match wouldn't work as it is bidirectional
 112                         int wildcard = uip.url.LastIndexOf ('*');
 113                         if (wildcard == -1)
 114                                 wildcard = uip.url.Length;      // exact match
 115
 116                         return (String.Compare (url, 0, uip.url, 0, wildcard, true, CultureInfo.InvariantCulture) == 0);
 117                 }
 118
 119                 public override SecurityElement ToXml ()
 120                 {
 121                         SecurityElement se = Element (version);
 122                         if (!IsEmpty ())
 123                                 se.AddAttribute ("Url", url);
 124                         return se;
 125                 }
 126
 127                 public override IPermission Union (IPermission target)
 128                 {
 129                         UrlIdentityPermission uip = Cast (target);
 130                         if (uip == null)
 131                                 return Copy ();
 132                         if (IsEmpty () && uip.IsEmpty ())
 133                                 return null;
 134                         if (uip.IsEmpty ())
 135                                 return Copy ();
 136                         if (IsEmpty ())
 137                                 return uip.Copy ();
 138                         if (Match (uip.url)) {
 139                                 // shortest form is the union
 140                                 if (url.Length < uip.url.Length)
 141                                         return Copy ();
 142                                 else
 143                                         return uip.Copy ();
 144                         }
 145                         throw new ArgumentException (Locale.GetText (
 146                                 "Cannot union two different urls."), "target");
 147                 }
 148
 149                 // IBuiltInPermission
 150                 int IBuiltInPermission.GetTokenIndex ()
 151                 {
 152                         return (int) BuiltInToken.UrlIdentity;
 153                 }
 154
 155                 // helpers
 156
 157                 private bool IsEmpty ()
 158                 {
 159                         return ((url == null) || (url.Length == 0));
 160                 }
 161
 162                 private UrlIdentityPermission Cast (IPermission target)
 163                 {
 164                         if (target == null)
 165                                 return null;
 166
 167                         UrlIdentityPermission uip = (target as UrlIdentityPermission);
 168                         if (uip == null) {
 169                                 ThrowInvalidPermission (target, typeof (UrlIdentityPermission));
 170                         }
 171
 172                         return uip;
 173                 }
 174
 175                 private bool Match (string target)
 176                 {
 177                         if ((url == null) || (target == null))
 178                                 return false;
 179
 180                         int wcu = url.LastIndexOf ('*');
 181                         int wct = target.LastIndexOf ('*');
 182                         int length = Int32.MaxValue;
 183
 184                         if ((wcu == -1) && (wct == -1)) {
 185                                 // no wildcard, this is an exact match
 186                                 length = Math.Max (url.Length, target.Length);
 187                         }
 188                         else if (wcu == -1) {
 189                                 // only "this" has a wildcard, use it
 190                                 length = wct;
 191                         }
 192                         else if (wct == -1) {
 193                                 // only "target" has a wildcard, use it
 194                                 length = wcu;
 195                         }
 196                         else {
 197                                 // both have wildcards, partial match with the smallest
 198                                 length = Math.Min (wcu, wct);
 199                         }
 200
 201                         return (String.Compare (url, 0, target, 0, length, true, CultureInfo.InvariantCulture) == 0);
 202                 }
 203         }
 204 }