mcs/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 //
   7 // (C) 2002, 2003 Motus Technologies Inc. (http://www.motus.com)
   8 //
   9
  10 using System.Collections;
  11 using System.Security.Cryptography;
  12 using System.Xml;
  13
  14 namespace System.Security.Cryptography.Xml {
  15
  16         public class Signature {
  17                 static XmlNamespaceManager dsigNsmgr;
  18
  19                 static Signature ()
  20                 {
  21                         dsigNsmgr = new XmlNamespaceManager (new NameTable ());
  22                         dsigNsmgr.AddNamespace ("xd", XmlSignature.NamespaceURI);
  23                 }
  24
  25                 private ArrayList list;
  26                 private SignedInfo info;
  27                 private KeyInfo key;
  28                 private string id;
  29                 private byte[] signature;
  30                 private XmlElement element;
  31
  32                 public Signature ()
  33                 {
  34                         list = new ArrayList ();
  35                 }
  36
  37                 public string Id {
  38                         get { return id; }
  39                         set {
  40                                 element = null;
  41                                 id = value;
  42                         }
  43                 }
  44
  45                 public KeyInfo KeyInfo {
  46                         get { return key; }
  47                         set {
  48                                 element = null;
  49                                 key = value;
  50                         }
  51                 }
  52
  53                 public IList ObjectList {
  54                         get { return list; }
  55                         set { list = ArrayList.Adapter (value); }
  56                 }
  57
  58                 public byte[] SignatureValue {
  59                         get { return signature; }
  60                         set {
  61                                 element = null;
  62                                 signature = value;
  63                         }
  64                 }
  65
  66                 public SignedInfo SignedInfo {
  67                         get { return info; }
  68                         set {
  69                                 element = null;
  70                                 info = value;
  71                         }
  72                 }
  73
  74                 public void AddObject (DataObject dataObject)
  75                 {
  76                         list.Add (dataObject);
  77                 }
  78
  79                 public XmlElement GetXml ()
  80                 {
  81                         if (element != null)
  82                                 return element;
  83
  84                         if (info == null)
  85                                 throw new CryptographicException ("SignedInfo");
  86                         if (signature == null)
  87                                 throw new CryptographicException ("SignatureValue");
  88
  89                         XmlDocument document = new XmlDocument ();
  90                         XmlElement xel = document.CreateElement (XmlSignature.ElementNames.Signature, XmlSignature.NamespaceURI);
  91                         if (id != null)
  92                                 xel.SetAttribute (XmlSignature.AttributeNames.Id, id);
  93
  94                         XmlNode xn = info.GetXml ();
  95                         XmlNode newNode = document.ImportNode (xn, true);
  96                         xel.AppendChild (newNode);
  97
  98                         if (signature != null) {
  99                                 XmlElement sv = document.CreateElement (XmlSignature.ElementNames.SignatureValue, XmlSignature.NamespaceURI);
 100                                 sv.InnerText = Convert.ToBase64String (signature);
 101                                 xel.AppendChild (sv);
 102                         }
 103
 104                         if (key != null) {
 105                                 xn = key.GetXml ();
 106                                 newNode = document.ImportNode (xn, true);
 107                                 xel.AppendChild (newNode);
 108                         }
 109
 110                         if (list.Count > 0) {
 111                                 foreach (DataObject obj in list) {
 112                                         xn = obj.GetXml ();
 113                                         newNode = document.ImportNode (xn, true);
 114                                         xel.AppendChild (newNode);
 115                                 }
 116                         }
 117
 118                         return xel;
 119                 }
 120
 121                 private string GetAttribute (XmlElement xel, string attribute)
 122                 {
 123                         XmlAttribute xa = xel.Attributes [attribute];
 124                         return ((xa != null) ? xa.InnerText : null);
 125                 }
 126
 127                 public void LoadXml (XmlElement value)
 128                 {
 129                         if (value == null)
 130                                 throw new ArgumentNullException ("value");
 131
 132                         if ((value.LocalName == XmlSignature.ElementNames.Signature) && (value.NamespaceURI == XmlSignature.NamespaceURI)) {
 133                                 id = GetAttribute (value, XmlSignature.AttributeNames.Id);
 134
 135                                 // LAMESPEC: This library is totally useless against eXtensibly Marked-up document.
 136                                 int i = NextElementPos (value.ChildNodes, 0, XmlSignature.ElementNames.SignedInfo, XmlSignature.NamespaceURI, true);
 137                                 XmlElement sinfo = (XmlElement) value.ChildNodes [i];
 138                                 info = new SignedInfo ();
 139                                 info.LoadXml (sinfo);
 140
 141                                 i = NextElementPos (value.ChildNodes, ++i, XmlSignature.ElementNames.SignatureValue, XmlSignature.NamespaceURI, true);
 142                                 XmlElement sigValue = (XmlElement) value.ChildNodes [i];
 143                                 signature = Convert.FromBase64String (sigValue.InnerText);
 144
 145                                 // signature isn't required: <element ref="ds:KeyInfo" minOccurs="0"/>
 146                                 i = NextElementPos (value.ChildNodes, ++i, XmlSignature.ElementNames.KeyInfo, XmlSignature.NamespaceURI, false);
 147                                 if (i > 0) {
 148                                         XmlElement kinfo = (XmlElement) value.ChildNodes [i];
 149                                         key = new KeyInfo ();
 150                                         key.LoadXml (kinfo);
 151                                 }
 152
 153                                 XmlNodeList xnl = value.SelectNodes ("xd:Object", dsigNsmgr);
 154                                 foreach (XmlElement xn in xnl) {
 155                                         DataObject obj = new DataObject ();
 156                                         obj.LoadXml (xn);
 157                                         AddObject (obj);
 158                                 }
 159                         }
 160                         else
 161                                 throw new CryptographicException ("Malformed element: Signature.");
 162
 163                         // if invalid
 164                         if (info == null)
 165                                 throw new CryptographicException ("SignedInfo");
 166                         if (signature == null)
 167                                 throw new CryptographicException ("SignatureValue");
 168                 }
 169
 170                 private int NextElementPos (XmlNodeList nl, int pos, string name, string ns, bool required)
 171                 {
 172                         while (pos < nl.Count) {
 173                                 if (nl [pos].NodeType == XmlNodeType.Element) {
 174                                         if (nl [pos].LocalName != name && nl [pos].NamespaceURI != ns) {
 175                                                 if (required)
 176                                                         throw new CryptographicException ("Malformed element " + name);
 177                                                 else
 178                                                         return -2;
 179                                         }
 180                                         return pos;
 181                                 }
 182                                 else
 183                                         pos++;
 184                         }
 185                         if (required)
 186                                 throw new CryptographicException ("Malformed element " + name);
 187                         return -1;
 188                 }
 189         }
 190 }