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