class/corlib/System.Security.Policy/HashMembershipCondition.cs

   1 //
   2 // System.Security.Policy.HashMembershipCondition.cs
   3 //
   4 // Authors:
   5 //      Jackson Harper (Jackson@LatitudeGeo.com)
   6 //      Sebastien Pouliot  <sebastien@ximian.com>
   7 //
   8 // (C) 2002 Jackson Harper, All rights reserved
   9 // Copyright (C) 2004-2005 Novell, Inc (http://www.novell.com)
  10 //
  11 // Permission is hereby granted, free of charge, to any person obtaining
  12 // a copy of this software and associated documentation files (the
  13 // "Software"), to deal in the Software without restriction, including
  14 // without limitation the rights to use, copy, modify, merge, publish,
  15 // distribute, sublicense, and/or sell copies of the Software, and to
  16 // permit persons to whom the Software is furnished to do so, subject to
  17 // the following conditions:
  18 //
  19 // The above copyright notice and this permission notice shall be
  20 // included in all copies or substantial portions of the Software.
  21 //
  22 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  23 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  24 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  25 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  26 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  27 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  28 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  29 //
  30
  31 #if !MOONLIGHT
  32
  33 using System.Collections;
  34 using System.Globalization;
  35 using System.Reflection;
  36 using System.Runtime.InteropServices;
  37 using System.Runtime.Serialization;
  38 using System.Security.Cryptography;
  39
  40 using Mono.Security.Cryptography;
  41
  42 namespace System.Security.Policy {
  43
  44         [Serializable]
  45         [ComVisible (true)]
  46         public sealed class HashMembershipCondition : IMembershipCondition, IDeserializationCallback, ISerializable {
  47                 private readonly int version = 1;
  48
  49                 private HashAlgorithm hash_algorithm;
  50                 private byte[] hash_value;
  51
  52                 // so System.Activator.CreateInstance can create an instance...
  53                 internal HashMembershipCondition ()
  54                 {
  55                 }
  56
  57                 public HashMembershipCondition (HashAlgorithm hashAlg, byte[] value)
  58                 {
  59                         if (hashAlg == null)
  60                                 throw new ArgumentNullException ("hashAlg");
  61                         if (value == null)
  62                                 throw new ArgumentNullException ("value");
  63
  64                         this.hash_algorithm = hashAlg;
  65                         this.hash_value = (byte[]) value.Clone ();
  66                 }
  67
  68                 //
  69                 // Public Properties
  70                 //
  71
  72                 public HashAlgorithm HashAlgorithm {
  73                         get {
  74                                 if (hash_algorithm == null)
  75                                         hash_algorithm = new SHA1Managed ();
  76                                 return hash_algorithm;
  77                         }
  78                         set {
  79                                 if (value == null)
  80                                         throw new ArgumentNullException ("HashAlgorithm");
  81                                 hash_algorithm = value;
  82                         }
  83                 }
  84
  85                 public byte[] HashValue {
  86                         get {
  87                                 if (hash_value == null)
  88                                         throw new ArgumentException (Locale.GetText ("No HashValue available."));
  89                                 return (byte[]) hash_value.Clone ();
  90                         }
  91                         set {
  92                                 if (value == null)
  93                                         throw new ArgumentNullException ("HashValue");
  94                                 hash_value = (byte[]) value.Clone ();
  95                         }
  96                 }
  97
  98                 //
  99                 // Public Methods
 100                 //
 101
 102                 public bool Check (Evidence evidence)
 103                 {
 104                         if (evidence == null)
 105                                 return false;
 106
 107                         IEnumerator e = evidence.GetHostEnumerator ();
 108                         while (e.MoveNext ()) {
 109                                 Hash hash = (e.Current as Hash);
 110                                 if (hash == null)
 111                                         continue;
 112                                 if (Compare (hash_value, hash.GenerateHash (hash_algorithm)))
 113                                         return true;
 114                                 break;
 115                         }
 116                         return false;
 117                 }
 118
 119                 public IMembershipCondition Copy ()
 120                 {
 121                         return new HashMembershipCondition (hash_algorithm, hash_value);
 122                 }
 123
 124                 public override bool Equals (object o)
 125                 {
 126                         HashMembershipCondition other = (o as HashMembershipCondition);
 127                         if (other == null)
 128                                 return false;
 129
 130                         return ((other.HashAlgorithm == hash_algorithm) &&
 131                                 Compare (hash_value, other.hash_value));
 132                 }
 133
 134                 public SecurityElement ToXml ()
 135                 {
 136                         return ToXml (null);
 137                 }
 138
 139                 public SecurityElement ToXml (PolicyLevel level)
 140                 {
 141                         SecurityElement se = MembershipConditionHelper.Element (typeof (HashMembershipCondition), version);
 142                         se.AddAttribute ("HashValue", CryptoConvert.ToHex (HashValue));
 143                         se.AddAttribute ("HashAlgorithm", hash_algorithm.GetType ().FullName);
 144                         return se;
 145                 }
 146
 147                 public void FromXml (SecurityElement e)
 148                 {
 149                         FromXml (e, null);
 150                 }
 151
 152                 public void FromXml (SecurityElement e, PolicyLevel level)
 153                 {
 154                         MembershipConditionHelper.CheckSecurityElement (e, "e", version, version);
 155
 156                         hash_value = CryptoConvert.FromHex (e.Attribute ("HashValue"));
 157
 158                         string algorithm = e.Attribute ("HashAlgorithm");
 159                         hash_algorithm = (algorithm == null) ? null : HashAlgorithm.Create (algorithm);
 160                 }
 161
 162                 public override int GetHashCode ()
 163                 {
 164                         // note: a Copy must have the same hash code
 165                         int code = hash_algorithm.GetType ().GetHashCode ();
 166                         if (hash_value != null) {
 167                                 foreach (byte b in hash_value) {
 168                                         code ^= b;
 169                                 }
 170                         }
 171                         return code;
 172                 }
 173
 174                 public override string ToString ()
 175                 {
 176                         Type alg_type = this.HashAlgorithm.GetType ();
 177                         return String.Format ("Hash - {0} {1} = {2}", alg_type.FullName,
 178                                 alg_type.Assembly, CryptoConvert.ToHex (HashValue));
 179                 }
 180
 181                 //
 182                 // Private Methods
 183                 //
 184
 185                 private bool Compare (byte[] expected, byte[] actual)
 186                 {
 187                         if (expected.Length != actual.Length)
 188                                 return false;
 189
 190                         int len = expected.Length;
 191                         for (int i = 0; i < len; i++) {
 192                                 if (expected [i] != actual [i])
 193                                         return false;
 194                         }
 195                         return true;
 196                 }
 197
 198                 [MonoTODO ("fx 2.0")]
 199                 void IDeserializationCallback.OnDeserialization (object sender)
 200                 {
 201                 }
 202
 203                 [MonoTODO ("fx 2.0")]
 204                 void ISerializable.GetObjectData (SerializationInfo info, StreamingContext context)
 205                 {
 206                 }
 207         }
 208 }
 209
 210 #endif
 211