mcs/class/System/System.Security.Cryptography.X509Certificates/X509SubjectKeyIdentifierExtension.cs

   1 //
   2 // System.Security.Cryptography.X509Certificates.X509SubjectKeyIdentifierExtension
   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 using MonoSecurity::Mono.Security.Cryptography;
  39
  40 namespace System.Security.Cryptography.X509Certificates {
  41
  42         public sealed class X509SubjectKeyIdentifierExtension : X509Extension {
  43
  44                 internal const string oid = "2.5.29.14";
  45                 internal const string friendlyName = "Subject Key Identifier";
  46
  47                 private byte[] _subjectKeyIdentifier;
  48                 private string _ski;
  49                 private AsnDecodeStatus _status;
  50
  51                 // constructors
  52
  53                 public X509SubjectKeyIdentifierExtension ()
  54                 {
  55                         _oid = new Oid (oid, friendlyName);
  56                 }
  57
  58                 public X509SubjectKeyIdentifierExtension (AsnEncodedData encodedSubjectKeyIdentifier, bool critical)
  59                 {
  60                         // ignore the Oid provided by encodedKeyUsage (our rules!)
  61                         _oid = new Oid (oid, friendlyName);
  62                         _raw = encodedSubjectKeyIdentifier.RawData;
  63                         base.Critical = critical;
  64                         _status = Decode (this.RawData);
  65                 }
  66
  67                 public X509SubjectKeyIdentifierExtension (byte[] subjectKeyIdentifier, bool critical)
  68                 {
  69                         if (subjectKeyIdentifier == null)
  70                                 throw new ArgumentNullException ("subjectKeyIdentifier");
  71                         if (subjectKeyIdentifier.Length == 0)
  72                                 throw new ArgumentException ("subjectKeyIdentifier");
  73
  74                         _oid = new Oid (oid, friendlyName);
  75                         base.Critical = critical;
  76                         _subjectKeyIdentifier = (byte[])subjectKeyIdentifier.Clone ();
  77                         RawData = Encode ();
  78                 }
  79
  80                 public X509SubjectKeyIdentifierExtension (string subjectKeyIdentifier, bool critical)
  81                 {
  82                         if (subjectKeyIdentifier == null)
  83                                 throw new ArgumentNullException ("subjectKeyIdentifier");
  84                         if (subjectKeyIdentifier.Length < 2)
  85                                 throw new ArgumentException ("subjectKeyIdentifier");
  86
  87                         _oid = new Oid (oid, friendlyName);
  88                         base.Critical = critical;
  89                         _subjectKeyIdentifier = FromHex (subjectKeyIdentifier);
  90                         RawData = Encode ();
  91                 }
  92
  93                 public X509SubjectKeyIdentifierExtension (PublicKey key, bool critical)
  94                         : this (key, X509SubjectKeyIdentifierHashAlgorithm.Sha1, critical)
  95                 {
  96                 }
  97
  98                 public X509SubjectKeyIdentifierExtension (PublicKey key, X509SubjectKeyIdentifierHashAlgorithm algorithm, bool critical)
  99                 {
 100                         if (key == null)
 101                                 throw new ArgumentNullException ("key");
 102
 103                         byte[] pkraw = key.EncodedKeyValue.RawData;
 104                         // compute SKI
 105                         switch (algorithm) {
 106                         // hash of the public key, excluding Tag, Length and unused bits values
 107                         case X509SubjectKeyIdentifierHashAlgorithm.Sha1:
 108                                 _subjectKeyIdentifier = SHA1.Create ().ComputeHash (pkraw);
 109                                 break;
 110                         // 0100 bit pattern followed by the 60 last bit of the hash
 111                         case X509SubjectKeyIdentifierHashAlgorithm.ShortSha1:
 112                                 byte[] hash = SHA1.Create ().ComputeHash (pkraw);
 113                                 _subjectKeyIdentifier = new byte [8];
 114                                 Buffer.BlockCopy (hash, 12, _subjectKeyIdentifier, 0, 8);
 115                                 _subjectKeyIdentifier [0] = (byte) (0x40 | (_subjectKeyIdentifier [0] & 0x0F));
 116                                 break;
 117                         // hash of the public key, including Tag, Length and unused bits values
 118                         case X509SubjectKeyIdentifierHashAlgorithm.CapiSha1:
 119                                 // CryptoAPI does that hash on the complete subjectPublicKeyInfo (unlike PKIX)
 120                                 // http://groups.google.ca/groups?selm=e7RqM%24plCHA.1488%40tkmsftngp02&oe=UTF-8&output=gplain
 121                                 ASN1 subjectPublicKeyInfo = new ASN1 (0x30);
 122                                 ASN1 algo = subjectPublicKeyInfo.Add (new ASN1 (0x30));
 123                                 algo.Add (new ASN1 (CryptoConfig.EncodeOID (key.Oid.Value)));
 124                                 algo.Add (new ASN1 (key.EncodedParameters.RawData));
 125                                 // add an extra byte for the unused bits (none)
 126                                 byte[] full = new byte [pkraw.Length + 1];
 127                                 Buffer.BlockCopy (pkraw, 0, full, 1, pkraw.Length);
 128                                 subjectPublicKeyInfo.Add (new ASN1 (0x03, full));
 129                                 _subjectKeyIdentifier = SHA1.Create ().ComputeHash (subjectPublicKeyInfo.GetBytes ());
 130                                 break;
 131                         default:
 132                                 throw new ArgumentException ("algorithm");
 133                         }
 134
 135                         _oid = new Oid (oid, friendlyName);
 136                         base.Critical = critical;
 137                         RawData = Encode ();
 138                 }
 139
 140                 // properties
 141
 142                 public string SubjectKeyIdentifier {
 143                         get {
 144                                 switch (_status) {
 145                                 case AsnDecodeStatus.Ok:
 146                                 case AsnDecodeStatus.InformationNotAvailable:
 147                                         if (_subjectKeyIdentifier != null)
 148                                                 _ski = CryptoConvert.ToHex (_subjectKeyIdentifier);
 149                                         return _ski;
 150                                 default:
 151                                         throw new CryptographicException ("Badly encoded extension.");
 152                                 }
 153                         }
 154                 }
 155
 156                 // methods
 157
 158                 public override void CopyFrom (AsnEncodedData encodedData)
 159                 {
 160                         if (encodedData == null)
 161                                 throw new ArgumentNullException ("encodedData");
 162
 163                         X509Extension ex = (encodedData as X509Extension);
 164                         if (ex == null)
 165                                 throw new ArgumentException (Locale.GetText ("Wrong type."), "encodedData");
 166
 167                         if (ex._oid == null)
 168                                 _oid = new Oid (oid, friendlyName);
 169                         else
 170                                 _oid = new Oid (ex._oid);
 171
 172                         RawData = ex.RawData;
 173                         base.Critical = ex.Critical;
 174                         // and we deal with the rest later
 175                         _status = Decode (this.RawData);
 176                 }
 177
 178                 // internal
 179
 180                 static internal byte FromHexChar (char c)
 181                 {
 182                         if ((c >= 'a') && (c <= 'f'))
 183                                 return (byte) (c - 'a' + 10);
 184                         if ((c >= 'A') && (c <= 'F'))
 185                                 return (byte) (c - 'A' + 10);
 186                         if ((c >= '0') && (c <= '9'))
 187                                 return (byte) (c - '0');
 188                         return 255;     // F
 189                 }
 190
 191                 static internal byte FromHexChars (char c1, char c2)
 192                 {
 193                         byte result = FromHexChar (c1);
 194                         if (result < 255)
 195                                 result = (byte) ((result << 4) | FromHexChar (c2));
 196                         return result;
 197                 }
 198
 199                 static internal byte[] FromHex (string hex)
 200                 {
 201                         // here we can't use CryptoConvert.FromHex because we
 202                         // must convert any *illegal* (non hex) 2 characters
 203                         // to 'FF' and ignore last char on odd length
 204                         if (hex == null)
 205                                 return null;
 206
 207                         int length = hex.Length >> 1;
 208
 209                         byte[] result = new byte [length]; // + (odd ? 1 : 0)];
 210                         int n = 0;
 211                         int i = 0;
 212                         while (n < length) {
 213                                 result [n++] = FromHexChars (hex [i++], hex [i++]);
 214                         }
 215                         return result;
 216                 }
 217
 218                 internal AsnDecodeStatus Decode (byte[] extension)
 219                 {
 220                         if ((extension == null) || (extension.Length == 0))
 221                                 return AsnDecodeStatus.BadAsn;
 222                         _ski = String.Empty;
 223                         if (extension [0] != 0x04)
 224                                 return AsnDecodeStatus.BadTag;
 225                         if (extension.Length == 2)
 226                                 return AsnDecodeStatus.InformationNotAvailable;
 227                         if (extension.Length < 3)
 228                                 return AsnDecodeStatus.BadLength;
 229
 230                         try {
 231                                 ASN1 ex = new ASN1 (extension);
 232                                 _subjectKeyIdentifier = ex.Value;
 233                         }
 234                         catch {
 235                                 return AsnDecodeStatus.BadAsn;
 236                         }
 237
 238                         return AsnDecodeStatus.Ok;
 239                 }
 240
 241                 internal byte[] Encode ()
 242                 {
 243                         ASN1 ex = new ASN1 (0x04, _subjectKeyIdentifier);
 244                         return ex.GetBytes ();
 245                 }
 246
 247                 internal override string ToString (bool multiLine)
 248                 {
 249                         switch (_status) {
 250                         case AsnDecodeStatus.BadAsn:
 251                                 return String.Empty;
 252                         case AsnDecodeStatus.BadTag:
 253                         case AsnDecodeStatus.BadLength:
 254                                 return FormatUnkownData (_raw);
 255                         case AsnDecodeStatus.InformationNotAvailable:
 256                                 return "Information Not Available";
 257                         }
 258
 259                         if (_oid.Value != oid)
 260                                 return String.Format ("Unknown Key Usage ({0})", _oid.Value);
 261
 262                         StringBuilder sb = new StringBuilder ();
 263
 264                         for (int i=0; i < _subjectKeyIdentifier.Length; i++) {
 265                                 sb.Append (_subjectKeyIdentifier [i].ToString ("x2"));
 266                                 if (i != _subjectKeyIdentifier.Length - 1)
 267                                         sb.Append (" ");
 268                         }
 269
 270                         if (multiLine)
 271                                 sb.Append (Environment.NewLine);
 272
 273                         return sb.ToString ();
 274                 }
 275         }
 276 }
 277
 278 #endif