mcs/class/corlib/Mono.Security/ASN1Convert.cs

   1 //
   2 // ASN1Convert.cs: Abstract Syntax Notation 1 convertion routines
   3 //
   4 // Authors:
   5 //      Sebastien Pouliot  <sebastien@ximian.com>
   6 //      Jesper Pedersen  <jep@itplus.dk>
   7 //
   8 // (C) 2003 Motus Technologies Inc. (http://www.motus.com)
   9 // (C) 2004 Novell (http://www.novell.com)
  10 // (C) 2004 IT+ A/S (http://www.itplus.dk)
  11 //
  12
  13 //
  14 // Copyright (C) 2004 Novell, Inc (http://www.novell.com)
  15 //
  16 // Permission is hereby granted, free of charge, to any person obtaining
  17 // a copy of this software and associated documentation files (the
  18 // "Software"), to deal in the Software without restriction, including
  19 // without limitation the rights to use, copy, modify, merge, publish,
  20 // distribute, sublicense, and/or sell copies of the Software, and to
  21 // permit persons to whom the Software is furnished to do so, subject to
  22 // the following conditions:
  23 //
  24 // The above copyright notice and this permission notice shall be
  25 // included in all copies or substantial portions of the Software.
  26 //
  27 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  28 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  29 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  30 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  31 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  32 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  33 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  34 //
  35
  36 using System;
  37 using System.Collections;
  38 using System.Globalization;
  39 using System.Security.Cryptography;
  40 using System.Text;
  41
  42 namespace Mono.Security {
  43
  44         // References:
  45         // a.   ITU ASN.1 standards (free download)
  46         //      http://www.itu.int/ITU-T/studygroups/com17/languages/
  47
  48 #if INSIDE_CORLIB
  49         internal
  50 #else
  51         public
  52 #endif
  53         sealed class ASN1Convert {
  54
  55                 private ASN1Convert ()
  56                 {
  57                 }
  58
  59                 // RFC3280, section 4.2.1.5
  60                 // CAs conforming to this profile MUST always encode certificate
  61                 // validity dates through the year 2049 as UTCTime; certificate validity
  62                 // dates in 2050 or later MUST be encoded as GeneralizedTime.
  63                 static public ASN1 FromDateTime (DateTime dt)
  64                 {
  65                         if (dt.Year < 2050) {
  66                                 // UTCTIME
  67                                 return new ASN1 (0x17, Encoding.ASCII.GetBytes (
  68                                         dt.ToUniversalTime ().ToString ("yyMMddHHmmss",
  69                                         CultureInfo.InvariantCulture) + "Z"));
  70                         }
  71                         else {
  72                                 // GENERALIZEDTIME
  73                                 return new ASN1 (0x18, Encoding.ASCII.GetBytes (
  74                                         dt.ToUniversalTime ().ToString ("yyyyMMddHHmmss",
  75                                         CultureInfo.InvariantCulture) + "Z"));
  76                         }
  77                 }
  78
  79                 static public ASN1 FromInt32 (Int32 value)
  80                 {
  81                         byte[] integer = BitConverterLE.GetBytes (value);
  82                         Array.Reverse (integer);
  83                         int x = 0;
  84                         while ((x < integer.Length) && (integer [x] == 0x00))
  85                                 x++;
  86                         ASN1 asn1 = new ASN1 (0x02);
  87                         switch (x) {
  88                         case 0:
  89                                 asn1.Value = integer;
  90                                 break;
  91                         case 4:
  92                                 asn1.Value = new byte [0];
  93                                 break;
  94                         default:
  95                                 byte[] smallerInt = new byte [4 - x];
  96                                 Buffer.BlockCopy (integer, x, smallerInt, 0, smallerInt.Length);
  97                                 asn1.Value = smallerInt;
  98                                 break;
  99                         }
 100                         return asn1;
 101                 }
 102
 103                 static public ASN1 FromOid (string oid)
 104                 {
 105                         if (oid == null)
 106                                 throw new ArgumentNullException ("oid");
 107
 108                         return new ASN1 (CryptoConfig.EncodeOID (oid));
 109                 }
 110
 111                 static public ASN1 FromUnsignedBigInteger (byte[] big)
 112                 {
 113                         if (big == null)
 114                                 throw new ArgumentNullException ("big");
 115
 116                         if (big [0] != 0x00) {
 117                                 // this first byte is added so we're sure this is an unsigned integer
 118                                 // however we can't feed it into RSAParameters or DSAParameters
 119                                 int length = big.Length + 1;
 120                                 byte[] uinteger = new byte [length];
 121                                 Buffer.BlockCopy (big, 0, uinteger, 1, length - 1);
 122                                 big = uinteger;
 123                         }
 124                         return new ASN1 (0x02, big);
 125                 }
 126
 127                 static public int ToInt32 (ASN1 asn1)
 128                 {
 129                         if (asn1 == null)
 130                                 throw new ArgumentNullException ("asn1");
 131                         if (asn1.Tag != 0x02)
 132                                 throw new FormatException ("Only integer can be converted");
 133
 134                         int x = 0;
 135                         for (int i=0; i < asn1.Value.Length; i++)
 136                                 x = (x << 8) + asn1.Value [i];
 137                         return x;
 138                 }
 139
 140                 // Convert a binary encoded OID to human readable string representation of
 141                 // an OID (IETF style). Based on DUMPASN1.C from Peter Gutmann.
 142                 static public string ToOid (ASN1 asn1)
 143                 {
 144                         if (asn1 == null)
 145                                 throw new ArgumentNullException ("asn1");
 146
 147                         byte[] aOID = asn1.Value;
 148                         StringBuilder sb = new StringBuilder ();
 149                         // Pick apart the OID
 150                         byte x = (byte) (aOID[0] / 40);
 151                         byte y = (byte) (aOID[0] % 40);
 152                         if (x > 2) {
 153                                 // Handle special case for large y if x = 2
 154                                 y += (byte) ((x - 2) * 40);
 155                                 x = 2;
 156                         }
 157                         sb.Append (x.ToString (CultureInfo.InvariantCulture));
 158                         sb.Append (".");
 159                         sb.Append (y.ToString (CultureInfo.InvariantCulture));
 160                         ulong val = 0;
 161                         for (x = 1; x < aOID.Length; x++) {
 162                                 val = ((val << 7) | ((byte) (aOID [x] & 0x7F)));
 163                                 if ( !((aOID [x] & 0x80) == 0x80)) {
 164                                         sb.Append (".");
 165                                         sb.Append (val.ToString (CultureInfo.InvariantCulture));
 166                                         val = 0;
 167                                 }
 168                         }
 169                         return sb.ToString ();
 170                 }
 171
 172                 static public DateTime ToDateTime (ASN1 time)
 173                 {
 174                         if (time == null)
 175                                 throw new ArgumentNullException ("time");
 176
 177                         string t = Encoding.ASCII.GetString (time.Value);
 178                         // to support both UTCTime and GeneralizedTime (and not so common format)
 179                         string mask = null;
 180                         switch (t.Length) {
 181                                 case 11:
 182                                         mask = "yyMMddHHmmZ"; // illegal I think ... must check
 183                                         break;
 184                                 case 13:
 185                                         // RFC3280: 4.1.2.5.1  UTCTime
 186                                         int year = Convert.ToInt16 (t.Substring (0, 2), CultureInfo.InvariantCulture);
 187                                         // Where YY is greater than or equal to 50, the
 188                                         // year SHALL be interpreted as 19YY; and
 189                                         // Where YY is less than 50, the year SHALL be
 190                                         // interpreted as 20YY.
 191                                         if (year >= 50)
 192                                                 t = "19" + t;
 193                                         else
 194                                                 t = "20" + t;
 195                                         mask = "yyyyMMddHHmmssZ";
 196                                         break;
 197                                 case 15:
 198                                         mask = "yyyyMMddHHmmssZ"; // GeneralizedTime
 199                                         break;
 200                         }
 201                         return DateTime.ParseExact (t, mask, null);
 202                 }
 203         }
 204 }