mcs/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 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
  32 namespace System.Security.Permissions {
  33
  34         [Serializable]
  35         public sealed class UrlIdentityPermission : CodeAccessPermission, IBuiltInPermission {
  36
  37                 private const int version = 1;
  38
  39                 private string url;
  40
  41                 public UrlIdentityPermission (PermissionState state)
  42                 {
  43                         // false == do not allow Unrestricted for Identity Permissions
  44                         CheckPermissionState (state, false);
  45 #if NET_2_0
  46                         url = String.Empty;
  47 #endif
  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 {
  59 #if !NET_2_0
  60                                 if (url == null)
  61                                         throw new NullReferenceException ("Url");
  62 #endif
  63                                 return url;
  64                         }
  65                         set {
  66                                 if (value == null)
  67                                         throw new ArgumentNullException ("Url");
  68                                 url = value;
  69                         }
  70                 }
  71
  72                 public override IPermission Copy ()
  73                 {
  74                         if (url == null) {
  75 #if NET_2_0
  76                                 return new UrlIdentityPermission (PermissionState.None);
  77 #else
  78                                 throw new NullReferenceException ("Url");
  79 #endif
  80                         }
  81                         else
  82                                 return new UrlIdentityPermission (url);
  83                 }
  84
  85                 public override void FromXml (SecurityElement esd)
  86                 {
  87                         // General validation in CodeAccessPermission
  88                         CheckSecurityElement (esd, "esd", 1, 1);
  89                         // Note: we do not (yet) care about the return value
  90                         // as we only accept version 1 (min/max values)
  91
  92                         string u = esd.Attribute ("Url");
  93                         if (u == null)
  94                                 url = String.Empty;
  95                         else
  96                                 Url = u;
  97                 }
  98
  99                 public override IPermission Intersect (IPermission target)
 100                 {
 101                         // if one permission is null (object or url) then there's no intersection
 102                         // if both are null then intersection is null
 103                         UrlIdentityPermission uip = Cast (target);
 104                         if ((uip == null) || (IsEmpty ()))
 105                                 return null;
 106                         if (Match (uip.url)) {
 107                                 // longest form is the intersection
 108                                 if (url.Length > uip.url.Length)
 109                                         return Copy ();
 110                                 else
 111                                         return uip.Copy ();
 112                         }
 113                         return null;
 114                 }
 115
 116                 public override bool IsSubsetOf (IPermission target)
 117                 {
 118                         UrlIdentityPermission uip = Cast (target);
 119                         if (uip == null)
 120                                 return IsEmpty ();
 121                         if (IsEmpty ())
 122                                 return true;
 123                         if (uip.url == null)
 124                                 return false;
 125
 126                         // here Match wouldn't work as it is bidirectional
 127                         int wildcard = uip.url.LastIndexOf ('*');
 128                         if (wildcard == -1)
 129                                 wildcard = uip.url.Length;      // exact match
 130
 131                         return (String.Compare (url, 0, uip.url, 0, wildcard, true, CultureInfo.InvariantCulture) == 0);
 132                 }
 133
 134                 public override SecurityElement ToXml ()
 135                 {
 136                         SecurityElement se = Element (version);
 137                         if (!IsEmpty ())
 138                                 se.AddAttribute ("Url", url);
 139                         return se;
 140                 }
 141
 142                 public override IPermission Union (IPermission target)
 143                 {
 144                         UrlIdentityPermission uip = Cast (target);
 145                         if (uip == null)
 146                                 return Copy ();
 147                         if (IsEmpty () && uip.IsEmpty ())
 148                                 return null;
 149                         if (uip.IsEmpty ())
 150                                 return Copy ();
 151                         if (IsEmpty ())
 152                                 return uip.Copy ();
 153                         if (Match (uip.url)) {
 154                                 // shortest form is the union
 155                                 if (url.Length < uip.url.Length)
 156                                         return Copy ();
 157                                 else
 158                                         return uip.Copy ();
 159                         }
 160 #if NET_2_0
 161                         throw new ArgumentException (Locale.GetText (
 162                                 "Cannot union two different urls."), "target");
 163 #else
 164                         return null;
 165 #endif
 166                 }
 167
 168                 // IBuiltInPermission
 169                 int IBuiltInPermission.GetTokenIndex ()
 170                 {
 171                         return (int) BuiltInToken.UrlIdentity;
 172                 }
 173
 174                 // helpers
 175
 176                 private bool IsEmpty ()
 177                 {
 178                         return ((url == null) || (url.Length == 0));
 179                 }
 180
 181                 private UrlIdentityPermission Cast (IPermission target)
 182                 {
 183                         if (target == null)
 184                                 return null;
 185
 186                         UrlIdentityPermission uip = (target as UrlIdentityPermission);
 187                         if (uip == null) {
 188                                 ThrowInvalidPermission (target, typeof (UrlIdentityPermission));
 189                         }
 190
 191                         return uip;
 192                 }
 193
 194                 private bool Match (string target)
 195                 {
 196                         if ((url == null) || (target == null))
 197                                 return false;
 198
 199                         int wcu = url.LastIndexOf ('*');
 200                         int wct = target.LastIndexOf ('*');
 201                         int length = Int32.MaxValue;
 202
 203                         if ((wcu == -1) && (wct == -1)) {
 204                                 // no wildcard, this is an exact match
 205                                 length = Math.Max (url.Length, target.Length);
 206                         }
 207                         else if (wcu == -1) {
 208                                 // only "this" has a wildcard, use it
 209                                 length = wct;
 210                         }
 211                         else if (wct == -1) {
 212                                 // only "target" has a wildcard, use it
 213                                 length = wcu;
 214                         }
 215                         else {
 216                                 // both have wildcards, partial match with the smallest
 217                                 length = Math.Min (wcu, wct);
 218                         }
 219
 220                         return (String.Compare (url, 0, target, 0, length, true, CultureInfo.InvariantCulture) == 0);
 221                 }
 222         }
 223 }