mcs/class/System.Security/System.Security.Cryptography.Xml/XmlDecryptionTransform.cs

   1 //
   2 // XmlDecryptionTransform.cs - XmlDecryptionTransform implementation for XML Encryption
   3 //
   4 // Author:
   5 //      Tim Coleman (tim@timcoleman.com)
   6 //
   7 // Copyright (C) Tim Coleman, 2004
   8
   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 #if NET_2_0
  31
  32 using System.Collections;
  33 using System.IO;
  34 using System.Xml;
  35
  36 namespace System.Security.Cryptography.Xml {
  37
  38         public class XmlDecryptionTransform : Transform {
  39
  40                 #region Fields
  41
  42                 EncryptedXml encryptedXml;
  43                 Type[] inputTypes;
  44                 Type[] outputTypes;
  45                 object inputObj;
  46                 ArrayList exceptUris;
  47
  48                 const string NamespaceUri = "http://www.w3.org/2002/07/decrypt#";
  49
  50                 #endregion // Fields
  51
  52                 #region Constructors
  53
  54                 public XmlDecryptionTransform ()
  55                 {
  56                         Algorithm = XmlSignature.AlgorithmNamespaces.XmlDecryptionTransform;
  57                         encryptedXml = new EncryptedXml ();
  58                         exceptUris = new ArrayList ();
  59                 }
  60
  61                 #endregion // Constructors
  62
  63                 #region Properties
  64
  65                 public EncryptedXml EncryptedXml {
  66                         get { return encryptedXml; }
  67                         set { encryptedXml = value; }
  68                 }
  69
  70                 public override Type[] InputTypes {
  71                         get {
  72                                 if (inputTypes == null)
  73                                         inputTypes = new Type [2] {typeof (System.IO.Stream), typeof (System.Xml.XmlDocument)};
  74
  75                                 return inputTypes;
  76                         }
  77                 }
  78
  79                 public override Type[] OutputTypes {
  80                         get {
  81                                 if (outputTypes == null)
  82                                         outputTypes = new Type [1] {typeof (System.Xml.XmlDocument)};
  83
  84                                 return outputTypes;
  85                         }
  86                 }
  87
  88                 #endregion // Properties
  89
  90                 #region Methods
  91
  92                 public void AddExceptUri (string uri)
  93                 {
  94                         exceptUris.Add (uri);
  95                 }
  96
  97                 private void ClearExceptUris ()
  98                 {
  99                         exceptUris.Clear ();
 100                 }
 101
 102                 [MonoTODO ("Verify")]
 103                 protected override XmlNodeList GetInnerXml ()
 104                 {
 105                         XmlDocument doc = new XmlDocument ();
 106                         doc.AppendChild (doc.CreateElement ("DecryptionTransform"));
 107
 108                         foreach (object o in exceptUris) {
 109                                 XmlElement element = doc.CreateElement ("Except", NamespaceUri);
 110                                 element.Attributes.Append (doc.CreateAttribute ("URI", NamespaceUri));
 111                                 element.Attributes ["URI", NamespaceUri].Value = (string) o;
 112                                 doc.DocumentElement.AppendChild (element);
 113                         }
 114
 115                         return doc.GetElementsByTagName ("Except", NamespaceUri);
 116                 }
 117
 118                 [MonoTODO ("Verify processing of ExceptURIs")]
 119                 public override object GetOutput ()
 120                 {
 121                         XmlDocument document;
 122                         if (inputObj is Stream) {
 123                                 document = new XmlDocument ();
 124                                 document.PreserveWhitespace = true;
 125                                 document.XmlResolver = GetResolver ();
 126                                 document.Load (new XmlSignatureStreamReader (
 127                                         new StreamReader (inputObj as Stream)));
 128                         }
 129                         else if (inputObj is XmlDocument) {
 130                                 document = inputObj as XmlDocument;
 131                         }
 132                         else
 133                                 throw new NullReferenceException ();
 134
 135                         XmlNodeList nodes = document.GetElementsByTagName ("EncryptedData", EncryptedXml.XmlEncNamespaceUrl);
 136                         foreach (XmlNode node in nodes) {
 137                                 if (node == document.DocumentElement && exceptUris.Contains ("#xpointer(/)"))
 138                                         break;
 139
 140                                 // Need to exclude based on ExceptURI.  Only accept #id references.
 141                                 foreach (string uri in exceptUris)
 142                                         if (IsTargetElement ((XmlElement) node, uri.Substring (1)))
 143                                                 break;
 144
 145                                 EncryptedData encryptedData = new EncryptedData ();
 146                                 encryptedData.LoadXml ((XmlElement) node);
 147                                 SymmetricAlgorithm symAlg = EncryptedXml.GetDecryptionKey (encryptedData, encryptedData.EncryptionMethod.KeyAlgorithm);
 148                                 EncryptedXml.ReplaceData ((XmlElement) node, EncryptedXml.DecryptData (encryptedData, symAlg));
 149                         }
 150
 151                         return document;
 152                 }
 153
 154                 public override object GetOutput (Type type)
 155                 {
 156                         if (type == typeof (Stream))
 157                                 return GetOutput ();
 158                         throw new ArgumentException ("type");
 159                 }
 160
 161                 [MonoTODO ("verify")]
 162                 protected virtual bool IsTargetElement (XmlElement inputElement, string idValue)
 163                 {
 164                         if ((inputElement == null) || (idValue == null))
 165                                 return false;
 166                         return (inputElement.Attributes ["id"].Value == idValue);
 167                 }
 168
 169                 [MonoTODO ("This doesn't seem to work in .NET")]
 170                 public override void LoadInnerXml (XmlNodeList nodeList)
 171                 {
 172                         if (nodeList == null)
 173                                 throw new NullReferenceException ();
 174
 175                         ClearExceptUris ();
 176                         foreach (XmlNode node in nodeList) {
 177                                 XmlElement element = node as XmlElement;
 178                                 if (element.NamespaceURI.Equals (NamespaceUri) && element.LocalName.Equals ("Except")) {
 179                                         string uri = element.Attributes ["URI", NamespaceUri].Value;
 180                                         if (!uri.StartsWith ("#"))
 181                                                 throw new CryptographicException ("A Uri attribute is required for a CipherReference element.");
 182                                         AddExceptUri (uri);
 183                                 }
 184                         }
 185                 }
 186
 187                 public override void LoadInput (object obj)
 188                 {
 189                         inputObj = obj;
 190                 }
 191
 192                 #endregion // Methods
 193         }
 194 }
 195
 196 #endif