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