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                 object lockObject;
  48
  49                 const string NamespaceUri = "http://www.w3.org/2002/07/decrypt#";
  50
  51                 #endregion // Fields
  52
  53                 #region Constructors
  54
  55                 public XmlDecryptionTransform ()
  56                 {
  57                         Algorithm = XmlSignature.AlgorithmNamespaces.XmlDecryptionTransform;
  58                         encryptedXml = new EncryptedXml ();
  59                         exceptUris = new ArrayList ();
  60                         lockObject = new object ();
  61                 }
  62
  63                 #endregion // Constructors
  64
  65                 #region Properties
  66
  67                 public EncryptedXml EncryptedXml {
  68                         get { return encryptedXml; }
  69                         set { encryptedXml = value; }
  70                 }
  71
  72                 public override Type[] InputTypes {
  73                         get {
  74                                 if (inputTypes == null) {
  75                                         lock (lockObject) {
  76                                                 inputTypes = new Type [2] {typeof (System.IO.Stream), typeof (System.Xml.XmlDocument)};
  77                                         }
  78                                 }
  79                                 return inputTypes;
  80                         }
  81                 }
  82
  83                 public override Type[] OutputTypes {
  84                         get {
  85                                 if (outputTypes == null) {
  86                                         lock (lockObject) {
  87                                                 outputTypes = new Type [1] {typeof (System.Xml.XmlDocument)};
  88                                         }
  89                                 }
  90                                 return outputTypes;
  91                         }
  92                 }
  93
  94                 #endregion // Properties
  95
  96                 #region Methods
  97
  98                 public void AddExceptUri (string uri)
  99                 {
 100                         exceptUris.Add (uri);
 101                 }
 102
 103                 private void ClearExceptUris ()
 104                 {
 105                         exceptUris.Clear ();
 106                 }
 107
 108                 [MonoTODO ("Verify")]
 109                 protected override XmlNodeList GetInnerXml ()
 110                 {
 111                         XmlDocument doc = new XmlDocument ();
 112                         doc.AppendChild (doc.CreateElement ("DecryptionTransform"));
 113
 114                         foreach (object o in exceptUris) {
 115                                 XmlElement element = doc.CreateElement ("Except", NamespaceUri);
 116                                 element.Attributes.Append (doc.CreateAttribute ("URI", NamespaceUri));
 117                                 element.Attributes ["URI", NamespaceUri].Value = (string) o;
 118                                 doc.DocumentElement.AppendChild (element);
 119                         }
 120
 121                         return doc.GetElementsByTagName ("Except", NamespaceUri);
 122                 }
 123
 124                 [MonoTODO ("Verify processing of ExceptURIs")]
 125                 public override object GetOutput ()
 126                 {
 127                         XmlDocument document;
 128                         if (inputObj is Stream) {
 129                                 document = new XmlDocument ();
 130                                 document.PreserveWhitespace = true;
 131                                 document.XmlResolver = GetResolver ();
 132                                 document.Load (new XmlSignatureStreamReader (
 133                                         new StreamReader (inputObj as Stream)));
 134                         }
 135                         else if (inputObj is XmlDocument) {
 136                                 document = inputObj as XmlDocument;
 137                         }
 138                         else
 139                                 throw new NullReferenceException ();
 140
 141                         XmlNodeList nodes = document.GetElementsByTagName ("EncryptedData", EncryptedXml.XmlEncNamespaceUrl);
 142                         foreach (XmlNode node in nodes) {
 143                                 if (node == document.DocumentElement && exceptUris.Contains ("#xpointer(/)"))
 144                                         break;
 145
 146                                 // Need to exclude based on ExceptURI.  Only accept #id references.
 147                                 foreach (string uri in exceptUris)
 148                                         if (IsTargetElement ((XmlElement) node, uri.Substring (1)))
 149                                                 break;
 150
 151                                 EncryptedData encryptedData = new EncryptedData ();
 152                                 encryptedData.LoadXml ((XmlElement) node);
 153                                 SymmetricAlgorithm symAlg = EncryptedXml.GetDecryptionKey (encryptedData, encryptedData.EncryptionMethod.KeyAlgorithm);
 154                                 EncryptedXml.ReplaceData ((XmlElement) node, EncryptedXml.DecryptData (encryptedData, symAlg));
 155                         }
 156
 157                         return document;
 158                 }
 159
 160                 public override object GetOutput (Type type)
 161                 {
 162                         if (type == Type.GetType ("Stream"))
 163                                 return GetOutput ();
 164                         throw new ArgumentException ("type");
 165                 }
 166
 167                 [MonoTODO ("verify")]
 168                 protected virtual bool IsTargetElement (XmlElement inputElement, string idValue)
 169                 {
 170                         return (inputElement.Attributes ["id"].Value == idValue);
 171                 }
 172
 173                 [MonoTODO ("This doesn't seem to work in .NET")]
 174                 public override void LoadInnerXml (XmlNodeList nodeList)
 175                 {
 176                         if (nodeList == null)
 177                                 throw new NullReferenceException ();
 178
 179                         ClearExceptUris ();
 180                         foreach (XmlNode node in nodeList) {
 181                                 XmlElement element = node as XmlElement;
 182                                 if (element.NamespaceURI.Equals (NamespaceUri) && element.LocalName.Equals ("Except")) {
 183                                         string uri = element.Attributes ["URI", NamespaceUri].Value;
 184                                         if (!uri.StartsWith ("#"))
 185                                                 throw new CryptographicException ("A Uri attribute is required for a CipherReference element.");
 186                                         AddExceptUri (uri);
 187                                 }
 188                         }
 189                 }
 190
 191                 public override void LoadInput (object obj)
 192                 {
 193                         inputObj = obj;
 194                 }
 195
 196                 #endregion // Methods
 197         }
 198 }
 199
 200 #endif