mcs/class/System/System.Security.Cryptography.X509Certificates/X509KeyUsageExtension.cs

   1 //
   2 // System.Security.Cryptography.X509Certificates.X509KeyUsageExtension
   3 //
   4 // Authors:
   5 //      Tim Coleman (tim@timcoleman.com)
   6 //      Sebastien Pouliot  <sebastien@ximian.com>
   7 //
   8 // Copyright (C) Tim Coleman, 2004
   9 // Copyright (C) 2004-2005 Novell Inc. (http://www.novell.com)
  10 //
  11 // Permission is hereby granted, free of charge, to any person obtaining
  12 // a copy of this software and associated documentation files (the
  13 // "Software"), to deal in the Software without restriction, including
  14 // without limitation the rights to use, copy, modify, merge, publish,
  15 // distribute, sublicense, and/or sell copies of the Software, and to
  16 // permit persons to whom the Software is furnished to do so, subject to
  17 // the following conditions:
  18 //
  19 // The above copyright notice and this permission notice shall be
  20 // included in all copies or substantial portions of the Software.
  21 //
  22 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  23 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  24 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  25 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  26 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  27 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  28 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  29 //
  30
  31 #if SECURITY_DEP
  32
  33 extern alias MonoSecurity;
  34
  35 using System.Text;
  36
  37 using MonoSecurity::Mono.Security;
  38
  39 namespace System.Security.Cryptography.X509Certificates {
  40
  41         public sealed class X509KeyUsageExtension : X509Extension {
  42
  43                 internal const string oid = "2.5.29.15";
  44                 internal const string friendlyName = "Key Usage";
  45
  46                 internal const X509KeyUsageFlags all = X509KeyUsageFlags.EncipherOnly | X509KeyUsageFlags.CrlSign |
  47                         X509KeyUsageFlags.KeyCertSign | X509KeyUsageFlags.KeyAgreement | X509KeyUsageFlags.DataEncipherment |
  48                         X509KeyUsageFlags.KeyEncipherment | X509KeyUsageFlags.NonRepudiation |
  49                         X509KeyUsageFlags.DigitalSignature | X509KeyUsageFlags.DecipherOnly;
  50
  51                 private X509KeyUsageFlags _keyUsages;
  52                 private AsnDecodeStatus _status;
  53
  54                 // constructors
  55
  56                 public X509KeyUsageExtension ()
  57                 {
  58                         _oid = new Oid (oid, friendlyName);
  59                 }
  60
  61                 public X509KeyUsageExtension (AsnEncodedData encodedKeyUsage, bool critical)
  62                 {
  63                         // ignore the Oid provided by encodedKeyUsage (our rules!)
  64                         _oid = new Oid (oid, friendlyName);
  65                         _raw = encodedKeyUsage.RawData;
  66                         base.Critical = critical;
  67                         _status = Decode (this.RawData);
  68                 }
  69
  70                 public X509KeyUsageExtension (X509KeyUsageFlags keyUsages, bool critical)
  71                 {
  72                         _oid = new Oid (oid, friendlyName);
  73                         base.Critical = critical;
  74                         _keyUsages = GetValidFlags (keyUsages);
  75                         RawData = Encode ();
  76                 }
  77
  78                 // properties
  79
  80                 public X509KeyUsageFlags KeyUsages {
  81                         get {
  82                                 switch (_status) {
  83                                 case AsnDecodeStatus.Ok:
  84                                 case AsnDecodeStatus.InformationNotAvailable:
  85                                         return _keyUsages;
  86                                 default:
  87                                         throw new CryptographicException ("Badly encoded extension.");
  88                                 }
  89                         }
  90                 }
  91
  92                 // methods
  93
  94                 public override void CopyFrom (AsnEncodedData encodedData)
  95                 {
  96                         if (encodedData == null)
  97                                 throw new ArgumentNullException ("encodedData");
  98
  99                         X509Extension ex = (encodedData as X509Extension);
 100                         if (ex == null)
 101                                 throw new ArgumentException (Locale.GetText ("Wrong type."), "encodedData");
 102
 103                         if (ex._oid == null)
 104                                 _oid = new Oid (oid, friendlyName);
 105                         else
 106                                 _oid = new Oid (ex._oid);
 107
 108                         RawData = ex.RawData;
 109                         base.Critical = ex.Critical;
 110                         // and we deal with the rest later
 111                         _status = Decode (this.RawData);
 112                 }
 113
 114                 // internal
 115
 116                 internal X509KeyUsageFlags GetValidFlags (X509KeyUsageFlags flags)
 117                 {
 118                         if ((flags & all) != flags)
 119                                 return (X509KeyUsageFlags) 0;
 120                         return flags;
 121                 }
 122
 123                 internal AsnDecodeStatus Decode (byte[] extension)
 124                 {
 125                         if ((extension == null) || (extension.Length == 0))
 126                                 return AsnDecodeStatus.BadAsn;
 127                         if (extension [0] != 0x03)
 128                                 return AsnDecodeStatus.BadTag;
 129                         if (extension.Length < 3)
 130                                 return AsnDecodeStatus.BadLength;
 131                         if (extension.Length < 4)
 132                                 return AsnDecodeStatus.InformationNotAvailable;
 133
 134                         try {
 135                                 ASN1 ex = new ASN1 (extension);
 136                                 int kubits = 0;
 137                                 int i = 1; // byte zero has the number of unused bits (ASN1's BITSTRING)
 138                                 while (i < ex.Value.Length)
 139                                         kubits = (kubits << 8) + ex.Value [i++];
 140
 141                                 _keyUsages = GetValidFlags ((X509KeyUsageFlags)kubits);
 142                         }
 143                         catch {
 144                                 return AsnDecodeStatus.BadAsn;
 145                         }
 146
 147                         return AsnDecodeStatus.Ok;
 148                 }
 149
 150                 internal byte[] Encode ()
 151                 {
 152                         ASN1 ex = null;
 153                         int kubits = (int)_keyUsages;
 154                         byte empty = 0;
 155
 156                         if (kubits == 0) {
 157                                 ex = new ASN1 (0x03, new byte[] { empty });
 158                         } else {
 159                                 // count empty bits (applicable to first byte only)
 160                                 int ku = ((kubits < Byte.MaxValue) ? kubits : (kubits >> 8));
 161                                 while (((ku & 0x01) == 0x00) && (empty < 8)) {
 162                                         empty++;
 163                                         ku >>= 1;
 164                                 }
 165
 166                                 if (kubits <= Byte.MaxValue) {
 167                                         ex = new ASN1 (0x03, new byte[] { empty, (byte)kubits });
 168                                 } else {
 169                                         ex = new ASN1 (0x03, new byte[] { empty, (byte)kubits, (byte)(kubits >> 8) });
 170                                 }
 171                         }
 172
 173                         return ex.GetBytes ();
 174                 }
 175
 176                 internal override string ToString (bool multiLine)
 177                 {
 178                         switch (_status) {
 179                         case AsnDecodeStatus.BadAsn:
 180                                 return String.Empty;
 181                         case AsnDecodeStatus.BadTag:
 182                         case AsnDecodeStatus.BadLength:
 183                                 return FormatUnkownData (_raw);
 184                         case AsnDecodeStatus.InformationNotAvailable:
 185                                 return "Information Not Available";
 186                         }
 187
 188                         if (_oid.Value != oid)
 189                                 return String.Format ("Unknown Key Usage ({0})", _oid.Value);
 190                         if (_keyUsages == 0)
 191                                 return "Information Not Available";
 192
 193                         StringBuilder sb = new StringBuilder ();
 194
 195                         if ((_keyUsages & X509KeyUsageFlags.DigitalSignature) != 0) {
 196                                 sb.Append ("Digital Signature");
 197                         }
 198                         if ((_keyUsages & X509KeyUsageFlags.NonRepudiation) != 0) {
 199                                 if (sb.Length > 0)
 200                                         sb.Append (", ");
 201                                 sb.Append ("Non-Repudiation");
 202                         }
 203                         if ((_keyUsages & X509KeyUsageFlags.KeyEncipherment) != 0) {
 204                                 if (sb.Length > 0)
 205                                         sb.Append (", ");
 206                                 sb.Append ("Key Encipherment");
 207                         }
 208                         if ((_keyUsages & X509KeyUsageFlags.DataEncipherment) != 0) {
 209                                 if (sb.Length > 0)
 210                                         sb.Append (", ");
 211                                 sb.Append ("Data Encipherment");
 212                         }
 213                         if ((_keyUsages & X509KeyUsageFlags.KeyAgreement) != 0) {
 214                                 if (sb.Length > 0)
 215                                         sb.Append (", ");
 216                                 sb.Append ("Key Agreement");
 217                         }
 218                         if ((_keyUsages & X509KeyUsageFlags.KeyCertSign) != 0) {
 219                                 if (sb.Length > 0)
 220                                         sb.Append (", ");
 221                                 sb.Append ("Certificate Signing");
 222                         }
 223                         if ((_keyUsages & X509KeyUsageFlags.CrlSign) != 0) {
 224                                 if (sb.Length > 0)
 225                                         sb.Append (", ");
 226                                 sb.Append ("Off-line CRL Signing, CRL Signing");
 227                         }
 228                         if ((_keyUsages & X509KeyUsageFlags.EncipherOnly) != 0) {
 229                                 if (sb.Length > 0)
 230                                         sb.Append (", ");
 231                                 sb.Append ("Encipher Only");
 232                         }
 233                         if ((_keyUsages & X509KeyUsageFlags.DecipherOnly) != 0) {
 234                                 if (sb.Length > 0)
 235                                         sb.Append (", ");
 236                                 sb.Append ("Decipher Only");
 237                         }
 238
 239                         int ku = (int)_keyUsages;
 240                         sb.Append (" (");
 241                         sb.Append (((byte)ku).ToString ("x2"));
 242                         if (ku > Byte.MaxValue) {
 243                                 sb.Append (" ");
 244                                 sb.Append (((byte)(ku >> 8)).ToString ("x2"));
 245                         }
 246                         sb.Append (")");
 247
 248                         if (multiLine)
 249                                 sb.Append (Environment.NewLine);
 250
 251                         return sb.ToString ();
 252                 }
 253         }
 254 }
 255
 256 #endif