class/System.Security/System.Security.Cryptography.Xml/Signature.cs

   1 //
   2 // Signature.cs - Signature implementation for XML Signature
   3 //
   4 // Author:
   5 //      Sebastien Pouliot (spouliot@motus.com)
   6 //      Tim Coleman (tim@timcoleman.com)
   7 //
   8 // (C) 2002, 2003 Motus Technologies Inc. (http://www.motus.com)
   9 // Copyright (C) Tim Coleman, 2004
  10 //
  11
  12 //
  13 // Permission is hereby granted, free of charge, to any person obtaining
  14 // a copy of this software and associated documentation files (the
  15 // "Software"), to deal in the Software without restriction, including
  16 // without limitation the rights to use, copy, modify, merge, publish,
  17 // distribute, sublicense, and/or sell copies of the Software, and to
  18 // permit persons to whom the Software is furnished to do so, subject to
  19 // the following conditions:
  20 //
  21 // The above copyright notice and this permission notice shall be
  22 // included in all copies or substantial portions of the Software.
  23 //
  24 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  25 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  26 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  27 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  28 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  29 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  30 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  31 //
  32
  33 using System.Collections;
  34 using System.Security.Cryptography;
  35 using System.Xml;
  36
  37 namespace System.Security.Cryptography.Xml {
  38
  39         public class Signature {
  40                 static XmlNamespaceManager dsigNsmgr;
  41
  42                 static Signature ()
  43                 {
  44                         dsigNsmgr = new XmlNamespaceManager (new NameTable ());
  45                         dsigNsmgr.AddNamespace ("xd", XmlSignature.NamespaceURI);
  46                 }
  47
  48                 private ArrayList list;
  49                 private SignedInfo info;
  50                 private KeyInfo key;
  51                 private string id;
  52                 private byte[] signature;
  53                 private XmlElement element;
  54
  55                 public Signature ()
  56                 {
  57                         list = new ArrayList ();
  58                 }
  59
  60                 public string Id {
  61                         get { return id; }
  62                         set {
  63                                 element = null;
  64                                 id = value;
  65                         }
  66                 }
  67
  68                 public KeyInfo KeyInfo {
  69                         get { return key; }
  70                         set {
  71                                 element = null;
  72                                 key = value;
  73                         }
  74                 }
  75
  76                 public IList ObjectList {
  77                         get { return list; }
  78                         set { list = ArrayList.Adapter (value); }
  79                 }
  80
  81                 public byte[] SignatureValue {
  82                         get { return signature; }
  83                         set {
  84                                 element = null;
  85                                 signature = value;
  86                         }
  87                 }
  88
  89                 public SignedInfo SignedInfo {
  90                         get { return info; }
  91                         set {
  92                                 element = null;
  93                                 info = value;
  94                         }
  95                 }
  96
  97                 public void AddObject (DataObject dataObject)
  98                 {
  99                         list.Add (dataObject);
 100                 }
 101
 102                 public XmlElement GetXml ()
 103                 {
 104                         return GetXml (null);
 105                 }
 106
 107                 internal XmlElement GetXml (XmlDocument document)
 108                 {
 109                         if (element != null)
 110                                 return element;
 111
 112                         if (info == null)
 113                                 throw new CryptographicException ("SignedInfo");
 114                         if (signature == null)
 115                                 throw new CryptographicException ("SignatureValue");
 116
 117                         if (document == null)
 118                                 document = new XmlDocument ();
 119
 120                         XmlElement xel = document.CreateElement (XmlSignature.ElementNames.Signature, XmlSignature.NamespaceURI);
 121                         if (id != null)
 122                                 xel.SetAttribute (XmlSignature.AttributeNames.Id, id);
 123
 124                         XmlNode xn = info.GetXml ();
 125                         XmlNode newNode = document.ImportNode (xn, true);
 126                         xel.AppendChild (newNode);
 127
 128                         if (signature != null) {
 129                                 XmlElement sv = document.CreateElement (XmlSignature.ElementNames.SignatureValue, XmlSignature.NamespaceURI);
 130                                 sv.InnerText = Convert.ToBase64String (signature);
 131                                 xel.AppendChild (sv);
 132                         }
 133
 134                         if (key != null) {
 135                                 xn = key.GetXml ();
 136                                 newNode = document.ImportNode (xn, true);
 137                                 xel.AppendChild (newNode);
 138                         }
 139
 140                         if (list.Count > 0) {
 141                                 foreach (DataObject obj in list) {
 142                                         xn = obj.GetXml ();
 143                                         newNode = document.ImportNode (xn, true);
 144                                         xel.AppendChild (newNode);
 145                                 }
 146                         }
 147
 148                         return xel;
 149                 }
 150
 151                 private string GetAttribute (XmlElement xel, string attribute)
 152                 {
 153                         XmlAttribute xa = xel.Attributes [attribute];
 154                         return ((xa != null) ? xa.InnerText : null);
 155                 }
 156
 157                 public void LoadXml (XmlElement value)
 158                 {
 159                         if (value == null)
 160                                 throw new ArgumentNullException ("value");
 161
 162                         if ((value.LocalName == XmlSignature.ElementNames.Signature) && (value.NamespaceURI == XmlSignature.NamespaceURI)) {
 163                                 id = GetAttribute (value, XmlSignature.AttributeNames.Id);
 164
 165                                 // LAMESPEC: This library is totally useless against eXtensibly Marked-up document.
 166                                 int i = NextElementPos (value.ChildNodes, 0, XmlSignature.ElementNames.SignedInfo, XmlSignature.NamespaceURI, true);
 167                                 XmlElement sinfo = (XmlElement) value.ChildNodes [i];
 168                                 info = new SignedInfo ();
 169                                 info.LoadXml (sinfo);
 170
 171                                 i = NextElementPos (value.ChildNodes, ++i, XmlSignature.ElementNames.SignatureValue, XmlSignature.NamespaceURI, true);
 172                                 XmlElement sigValue = (XmlElement) value.ChildNodes [i];
 173                                 signature = Convert.FromBase64String (sigValue.InnerText);
 174
 175                                 // signature isn't required: <element ref="ds:KeyInfo" minOccurs="0"/>
 176                                 i = NextElementPos (value.ChildNodes, ++i, XmlSignature.ElementNames.KeyInfo, XmlSignature.NamespaceURI, false);
 177                                 if (i > 0) {
 178                                         XmlElement kinfo = (XmlElement) value.ChildNodes [i];
 179                                         key = new KeyInfo ();
 180                                         key.LoadXml (kinfo);
 181                                 }
 182
 183                                 XmlNodeList xnl = value.SelectNodes ("xd:Object", dsigNsmgr);
 184                                 foreach (XmlElement xn in xnl) {
 185                                         DataObject obj = new DataObject ();
 186                                         obj.LoadXml (xn);
 187                                         AddObject (obj);
 188                                 }
 189                         }
 190                         else
 191                                 throw new CryptographicException ("Malformed element: Signature.");
 192
 193                         // if invalid
 194                         if (info == null)
 195                                 throw new CryptographicException ("SignedInfo");
 196                         if (signature == null)
 197                                 throw new CryptographicException ("SignatureValue");
 198                 }
 199
 200                 private int NextElementPos (XmlNodeList nl, int pos, string name, string ns, bool required)
 201                 {
 202                         while (pos < nl.Count) {
 203                                 if (nl [pos].NodeType == XmlNodeType.Element) {
 204                                         if (nl [pos].LocalName != name || nl [pos].NamespaceURI != ns) {
 205                                                 if (required)
 206                                                         throw new CryptographicException ("Malformed element " + name);
 207                                                 else
 208                                                         return -2;
 209                                         }
 210                                         else
 211                                                 return pos;
 212                                 }
 213                                 else
 214                                         pos++;
 215                         }
 216                         if (required)
 217                                 throw new CryptographicException ("Malformed element " + name);
 218                         return -1;
 219                 }
 220         }
 221 }