mcs/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 !NET_2_1
  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 #if NET_2_0
  46         [ComVisible (true)]
  47         public sealed class HashMembershipCondition : IMembershipCondition, IDeserializationCallback, ISerializable {
  48 #else
  49         public sealed class HashMembershipCondition : IMembershipCondition {
  50 #endif
  51                 private readonly int version = 1;
  52
  53                 private HashAlgorithm hash_algorithm;
  54                 private byte[] hash_value;
  55
  56                 // so System.Activator.CreateInstance can create an instance...
  57                 internal HashMembershipCondition ()
  58                 {
  59                 }
  60
  61                 public HashMembershipCondition (HashAlgorithm hashAlg, byte[] value)
  62                 {
  63                         if (hashAlg == null)
  64                                 throw new ArgumentNullException ("hashAlg");
  65                         if (value == null)
  66                                 throw new ArgumentNullException ("value");
  67
  68                         this.hash_algorithm = hashAlg;
  69                         this.hash_value = (byte[]) value.Clone ();
  70                 }
  71
  72                 //
  73                 // Public Properties
  74                 //
  75
  76                 public HashAlgorithm HashAlgorithm {
  77                         get {
  78                                 if (hash_algorithm == null)
  79                                         hash_algorithm = new SHA1Managed ();
  80                                 return hash_algorithm;
  81                         }
  82                         set {
  83                                 if (value == null)
  84                                         throw new ArgumentNullException ("HashAlgorithm");
  85                                 hash_algorithm = value;
  86                         }
  87                 }
  88
  89                 public byte[] HashValue {
  90                         get {
  91                                 if (hash_value == null)
  92                                         throw new ArgumentException (Locale.GetText ("No HashValue available."));
  93                                 return (byte[]) hash_value.Clone ();
  94                         }
  95                         set {
  96                                 if (value == null)
  97                                         throw new ArgumentNullException ("HashValue");
  98                                 hash_value = (byte[]) value.Clone ();
  99                         }
 100                 }
 101
 102                 //
 103                 // Public Methods
 104                 //
 105
 106                 public bool Check (Evidence evidence)
 107                 {
 108                         if (evidence == null)
 109                                 return false;
 110
 111                         IEnumerator e = evidence.GetHostEnumerator ();
 112                         while (e.MoveNext ()) {
 113                                 Hash hash = (e.Current as Hash);
 114                                 if (hash == null)
 115                                         continue;
 116                                 if (Compare (hash_value, hash.GenerateHash (hash_algorithm)))
 117                                         return true;
 118                                 break;
 119                         }
 120                         return false;
 121                 }
 122
 123                 public IMembershipCondition Copy ()
 124                 {
 125                         return new HashMembershipCondition (hash_algorithm, hash_value);
 126                 }
 127
 128                 public override bool Equals (object o)
 129                 {
 130                         HashMembershipCondition other = (o as HashMembershipCondition);
 131                         if (other == null)
 132                                 return false;
 133
 134                         return ((other.HashAlgorithm == hash_algorithm) &&
 135                                 Compare (hash_value, other.hash_value));
 136                 }
 137
 138                 public SecurityElement ToXml ()
 139                 {
 140                         return ToXml (null);
 141                 }
 142
 143                 public SecurityElement ToXml (PolicyLevel level)
 144                 {
 145                         SecurityElement se = MembershipConditionHelper.Element (typeof (HashMembershipCondition), version);
 146                         se.AddAttribute ("HashValue", CryptoConvert.ToHex (HashValue));
 147                         se.AddAttribute ("HashAlgorithm", hash_algorithm.GetType ().FullName);
 148                         return se;
 149                 }
 150
 151                 public void FromXml (SecurityElement e)
 152                 {
 153                         FromXml (e, null);
 154                 }
 155
 156                 public void FromXml (SecurityElement e, PolicyLevel level)
 157                 {
 158                         MembershipConditionHelper.CheckSecurityElement (e, "e", version, version);
 159
 160                         hash_value = CryptoConvert.FromHex (e.Attribute ("HashValue"));
 161
 162                         string algorithm = e.Attribute ("HashAlgorithm");
 163                         hash_algorithm = (algorithm == null) ? null : HashAlgorithm.Create (algorithm);
 164                 }
 165
 166                 public override int GetHashCode ()
 167                 {
 168                         // note: a Copy must have the same hash code
 169                         int code = hash_algorithm.GetType ().GetHashCode ();
 170                         if (hash_value != null) {
 171                                 foreach (byte b in hash_value) {
 172                                         code ^= b;
 173                                 }
 174                         }
 175                         return code;
 176                 }
 177
 178                 public override string ToString ()
 179                 {
 180                         Type alg_type = this.HashAlgorithm.GetType ();
 181                         return String.Format ("Hash - {0} {1} = {2}", alg_type.FullName,
 182                                 alg_type.Assembly, CryptoConvert.ToHex (HashValue));
 183                 }
 184
 185                 //
 186                 // Private Methods
 187                 //
 188
 189                 private bool Compare (byte[] expected, byte[] actual)
 190                 {
 191                         if (expected.Length != actual.Length)
 192                                 return false;
 193
 194                         int len = expected.Length;
 195                         for (int i = 0; i < len; i++) {
 196                                 if (expected [i] != actual [i])
 197                                         return false;
 198                         }
 199                         return true;
 200                 }
 201
 202 #if NET_2_0
 203                 [MonoTODO ("fx 2.0")]
 204                 void IDeserializationCallback.OnDeserialization (object sender)
 205                 {
 206                 }
 207
 208                 [MonoTODO ("fx 2.0")]
 209                 void ISerializable.GetObjectData (SerializationInfo info, StreamingContext context)
 210                 {
 211                 }
 212 #endif
 213         }
 214 }
 215
 216 #endif
 217