mcs/class/System.Web/System.Web.Configuration/MachineKeyConfigHandler.cs

   1 //
   2 // System.Web.Configuration.MachineKeyConfigHandler
   3 //
   4 // Authors:
   5 //      Gonzalo Paniagua Javier (gonzalo@ximian.com)
   6 //
   7 // (C) 2002 Ximian, Inc (http://www.ximian.com)
   8 //
   9
  10 using System;
  11 using System.Collections;
  12 using System.Configuration;
  13 using System.Security.Cryptography;
  14 using System.Xml;
  15
  16 namespace System.Web.Configuration
  17 {
  18         class MachineKeyConfigHandler : IConfigurationSectionHandler
  19         {
  20                 static byte [] autogenerated;
  21                 static MachineKeyConfigHandler ()
  22                 {
  23                         autogenerated = new byte [64];
  24                         RNGCryptoServiceProvider cp = new RNGCryptoServiceProvider ();
  25                         cp.GetBytes (autogenerated);
  26                 }
  27
  28                 static byte ToHexValue (char c, bool high)
  29                 {
  30                         byte v;
  31                         if (c >= '0' && c <= '9')
  32                                 v = (byte) (c - '0');
  33                         else if (c >= 'a' && c <= 'f')
  34                                 v = (byte) (c - 'a' + 10);
  35                         else if (c >= 'A' && c <= 'F')
  36                                 v = (byte) (c - 'A' + 10);
  37                         else
  38                                 throw new ArgumentException ("Invalid hex character");
  39
  40                         if (high)
  41                                 v <<= 4;
  42
  43                         return v;
  44                 }
  45
  46                 internal static byte [] GetBytes (string key, int len)
  47                 {
  48                         byte [] result = new byte [len / 2];
  49                         for (int i = 0; i < len; i += 2)
  50                                 result [i / 2] = (byte) (ToHexValue (key [i], true) + ToHexValue (key [i + 1], false));
  51
  52                         return result;
  53                 }
  54
  55                 static byte [] MakeKey (string key)
  56                 {
  57                         if (key == null || key == "AutoGenerated")
  58                                 return autogenerated;
  59
  60                         int len = key.Length;
  61                         if (len < 40 || len > 128 || (len % 2) == 1)
  62                                 throw new ArgumentException ("Invalid key length");
  63
  64                         return GetBytes (key, len);
  65                 }
  66
  67                 public object Create (object parent, object context, XmlNode section)
  68                 {
  69                         if (section.HasChildNodes)
  70                                 ThrowException ("Child nodes not allowed here", section.FirstChild);
  71
  72                         MachineKeyConfig config = new MachineKeyConfig (parent);
  73
  74                         string validationKey = AttValue ("validationKey", section);
  75                         try {
  76                                 config.ValidationKey = MakeKey (validationKey);
  77                         } catch (ArgumentException e) {
  78                                 ThrowException (e.Message, section);
  79                         }
  80
  81                         string decryptionKey = AttValue ("decryptionKey", section);
  82                         try {
  83                                 config.DecryptionKey = MakeKey (decryptionKey);
  84                         } catch (ArgumentException e) {
  85                                 ThrowException (e.Message, section);
  86                         }
  87
  88                         string validation = AttValue ("validation", section);
  89                         if (validation != "SHA1" && validation != "MD5" && validation != "3DES")
  90                                 ThrowException ("Invalid 'validation' value", section);
  91
  92                         config.ValidationType = validation;
  93
  94                         if (section.Attributes != null && section.Attributes.Count != 0)
  95                                 ThrowException ("Unrecognized attribute", section);
  96
  97                         MachineKeyConfig.MachineKey = config;
  98                         return config;
  99                 }
 100
 101                 // A few methods to save some typing
 102                 static string AttValue (string name, XmlNode node)
 103                 {
 104                         return HandlersUtil.ExtractAttributeValue (name, node, true);
 105                 }
 106
 107                 static void ThrowException (string message, XmlNode node)
 108                 {
 109                         HandlersUtil.ThrowException (message, node);
 110                 }
 111                 //
 112
 113         }
 114 }
 115