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

   1 //
   2 // System.Security.Policy.HashMembershipCondition
   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 using System.Collections;
  32 using System.Globalization;
  33 using System.Reflection;
  34 using System.Runtime.InteropServices;
  35 using System.Runtime.Serialization;
  36 using System.Security.Cryptography;
  37
  38 using Mono.Security.Cryptography;
  39
  40 namespace System.Security.Policy {
  41
  42         [Serializable]
  43 #if NET_2_0
  44         [ComVisible (true)]
  45         public sealed class HashMembershipCondition : IMembershipCondition, IDeserializationCallback, ISerializable {
  46 #else
  47         public sealed class HashMembershipCondition : IMembershipCondition {
  48 #endif
  49                 private readonly int version = 1;
  50
  51                 private HashAlgorithm hash_algorithm;
  52                 private byte[] hash_value;
  53
  54                 // so System.Activator.CreateInstance can create an instance...
  55                 internal HashMembershipCondition ()
  56                 {
  57                 }
  58
  59                 public HashMembershipCondition (HashAlgorithm hash_algorithm, byte[] hash_value)
  60                 {
  61                         if (hash_algorithm == null)
  62                                 throw new ArgumentNullException ("hash_algorithm");
  63                         if (hash_value == null)
  64                                 throw new ArgumentNullException ("hash_value");
  65
  66                         this.hash_algorithm = hash_algorithm;
  67                         this.hash_value = (byte[]) hash_value.Clone ();
  68                 }
  69
  70                 //
  71                 // Public Properties
  72                 //
  73
  74                 public HashAlgorithm HashAlgorithm {
  75                         get {
  76                                 if (hash_algorithm == null)
  77                                         hash_algorithm = new SHA1Managed ();
  78                                 return hash_algorithm;
  79                         }
  80                         set {
  81                                 if (value == null)
  82                                         throw new ArgumentNullException ("HashAlgorithm");
  83                                 hash_algorithm = value;
  84                         }
  85                 }
  86
  87                 public byte[] HashValue {
  88                         get {
  89                                 if (hash_value == null)
  90                                         throw new ArgumentException (Locale.GetText ("No HashValue available."));
  91                                 return (byte[]) hash_value.Clone ();
  92                         }
  93                         set {
  94                                 if (value == null)
  95                                         throw new ArgumentNullException ("HashValue");
  96                                 hash_value = (byte[]) value.Clone ();
  97                         }
  98                 }
  99
 100                 //
 101                 // Public Methods
 102                 //
 103
 104                 public bool Check (Evidence evidence)
 105                 {
 106                         if (evidence == null)
 107                                 return false;
 108
 109                         IEnumerator e = evidence.GetHostEnumerator ();
 110                         while (e.MoveNext ()) {
 111                                 Hash hash = (e.Current as Hash);
 112                                 if (hash == null)
 113                                         continue;
 114                                 if (Compare (hash_value, hash.GenerateHash (hash_algorithm)))
 115                                         return true;
 116                                 break;
 117                         }
 118                         return false;
 119                 }
 120
 121                 public IMembershipCondition Copy ()
 122                 {
 123                         return new HashMembershipCondition (hash_algorithm, hash_value);
 124                 }
 125
 126                 public override bool Equals (object o)
 127                 {
 128                         HashMembershipCondition other = (o as HashMembershipCondition);
 129                         if (other == null)
 130                                 return false;
 131
 132                         return ((other.HashAlgorithm == hash_algorithm) &&
 133                                 Compare (hash_value, other.hash_value));
 134                 }
 135
 136                 public SecurityElement ToXml ()
 137                 {
 138                         return ToXml (null);
 139                 }
 140
 141                 public SecurityElement ToXml (PolicyLevel level)
 142                 {
 143                         SecurityElement se = MembershipConditionHelper.Element (typeof (HashMembershipCondition), version);
 144                         se.AddAttribute ("HashValue", CryptoConvert.ToHex (HashValue));
 145                         se.AddAttribute ("HashAlgorithm", hash_algorithm.GetType ().FullName);
 146                         return se;
 147                 }
 148
 149                 public void FromXml (SecurityElement element)
 150                 {
 151                         FromXml (element, null);
 152                 }
 153
 154                 public void FromXml (SecurityElement e, PolicyLevel level)
 155                 {
 156                         MembershipConditionHelper.CheckSecurityElement (e, "e", version, version);
 157
 158                         hash_value = CryptoConvert.FromHex (e.Attribute ("HashValue"));
 159
 160                         string algorithm = e.Attribute ("HashAlgorithm");
 161                         hash_algorithm = (algorithm == null) ? null : HashAlgorithm.Create (algorithm);
 162                 }
 163
 164                 public override int GetHashCode ()
 165                 {
 166                         // note: a Copy must have the same hash code
 167                         int code = hash_algorithm.GetType ().GetHashCode ();
 168                         if (hash_value != null) {
 169                                 foreach (byte b in hash_value) {
 170                                         code ^= b;
 171                                 }
 172                         }
 173                         return code;
 174                 }
 175
 176                 public override string ToString ()
 177                 {
 178                         Type alg_type = this.HashAlgorithm.GetType ();
 179                         return String.Format ("Hash - {0} {1} = {2}", alg_type.FullName,
 180                                 alg_type.Assembly, CryptoConvert.ToHex (HashValue));
 181                 }
 182
 183                 //
 184                 // Private Methods
 185                 //
 186
 187                 private bool Compare (byte[] expected, byte[] actual)
 188                 {
 189                         if (expected.Length != actual.Length)
 190                                 return false;
 191
 192                         int len = expected.Length;
 193                         for (int i = 0; i < len; i++) {
 194                                 if (expected [i] != actual [i])
 195                                         return false;
 196                         }
 197                         return true;
 198                 }
 199
 200 #if NET_2_0
 201                 [MonoTODO ("fx 2.0")]
 202                 void IDeserializationCallback.OnDeserialization (object sender)
 203                 {
 204                 }
 205
 206                 [MonoTODO ("fx 2.0")]
 207                 void ISerializable.GetObjectData (SerializationInfo info, StreamingContext context)
 208                 {
 209                 }
 210 #endif
 211         }
 212 }
 213