mcs/class/corlib/Mono.Security.X509.Extensions/BasicConstraintsExtension.cs

   1 //
   2 // BasicConstraintsExtension.cs: Handles X.509 BasicConstrains extensions.
   3 //
   4 // Author:
   5 //      Sebastien Pouliot  <sebastien@ximian.com>
   6 //
   7 // (C) 2003 Motus Technologies Inc. (http://www.motus.com)
   8 // Copyright (C) 2004-2005 Novell, Inc (http://www.novell.com)
   9 //
  10 // Permission is hereby granted, free of charge, to any person obtaining
  11 // a copy of this software and associated documentation files (the
  12 // "Software"), to deal in the Software without restriction, including
  13 // without limitation the rights to use, copy, modify, merge, publish,
  14 // distribute, sublicense, and/or sell copies of the Software, and to
  15 // permit persons to whom the Software is furnished to do so, subject to
  16 // the following conditions:
  17 //
  18 // The above copyright notice and this permission notice shall be
  19 // included in all copies or substantial portions of the Software.
  20 //
  21 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  22 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  23 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  24 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  25 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  26 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  27 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  28 //
  29
  30 using System;
  31 using System.Globalization;
  32 using System.Text;
  33
  34 using Mono.Security;
  35 using Mono.Security.X509;
  36
  37 namespace Mono.Security.X509.Extensions {
  38
  39         // References:
  40         // 1.   RFC 3280: Internet X.509 Public Key Infrastructure, Section 4.2.1.10
  41         //      http://www.ietf.org/rfc/rfc3280.txt
  42
  43         /* id-ce-basicConstraints OBJECT IDENTIFIER ::=  { id-ce 19 }
  44          *
  45          * BasicConstraints ::= SEQUENCE {
  46          *      cA                      BOOLEAN DEFAULT FALSE,
  47          *      pathLenConstraint       INTEGER (0..MAX) OPTIONAL
  48          * }
  49          */
  50 #if INSIDE_CORLIB
  51         internal
  52 #else
  53         public
  54 #endif
  55         class BasicConstraintsExtension : X509Extension {
  56
  57                 public const int NoPathLengthConstraint = -1;
  58
  59                 private bool cA;
  60                 private int pathLenConstraint;
  61
  62                 public BasicConstraintsExtension () : base ()
  63                 {
  64                         extnOid = "2.5.29.19";
  65                         pathLenConstraint = NoPathLengthConstraint;
  66                 }
  67
  68                 public BasicConstraintsExtension (ASN1 asn1) : base (asn1) {}
  69
  70                 public BasicConstraintsExtension (X509Extension extension) : base (extension) {}
  71
  72                 protected override void Decode ()
  73                 {
  74                         // default values
  75                         cA = false;
  76                         pathLenConstraint = NoPathLengthConstraint;
  77
  78                         ASN1 sequence = new ASN1 (extnValue.Value);
  79                         if (sequence.Tag != 0x30)
  80                                 throw new ArgumentException ("Invalid BasicConstraints extension");
  81                         int n = 0;
  82                         ASN1 a = sequence [n++];
  83                         if ((a != null) && (a.Tag == 0x01)) {
  84                                 cA = (a.Value [0] == 0xFF);
  85                                 a = sequence [n++];
  86                         }
  87                         if ((a != null) && (a.Tag == 0x02))
  88                                 pathLenConstraint = ASN1Convert.ToInt32 (a);
  89                 }
  90
  91                 protected override void Encode ()
  92                 {
  93                         ASN1 seq = new ASN1 (0x30);
  94                         if (cA)
  95                                 seq.Add (new ASN1 (0x01, new byte[] { 0xFF }));
  96                         // CAs MUST NOT include the pathLenConstraint field unless the cA boolean is asserted
  97                         if (cA && (pathLenConstraint >= 0))
  98                                 seq.Add (ASN1Convert.FromInt32 (pathLenConstraint));
  99
 100                         extnValue = new ASN1 (0x04);
 101                         extnValue.Add (seq);
 102                 }
 103
 104                 public bool CertificateAuthority {
 105                         get { return cA; }
 106                         set { cA = value; }
 107                 }
 108
 109                 public override string Name {
 110                         get { return "Basic Constraints"; }
 111                 }
 112
 113                 public int PathLenConstraint {
 114                         get { return pathLenConstraint; }
 115                         set {
 116                                 if (value < NoPathLengthConstraint) {
 117                                         string msg = Locale.GetText ("PathLenConstraint must be positive or -1 for none ({0}).", value);
 118                                         throw new ArgumentOutOfRangeException (msg);
 119                                 }
 120                                 pathLenConstraint = value;
 121                         }
 122                 }
 123
 124                 public override string ToString ()
 125                 {
 126                         StringBuilder sb = new StringBuilder ();
 127                         sb.Append ("Subject Type=");
 128                         sb.Append ((cA) ? "CA" : "End Entity");
 129                         sb.Append (Environment.NewLine);
 130                         sb.Append ("Path Length Constraint=");
 131                         if (pathLenConstraint == NoPathLengthConstraint)
 132                                 sb.Append ("None");
 133                         else
 134                                 sb.Append (pathLenConstraint.ToString (CultureInfo.InvariantCulture));
 135                         sb.Append (Environment.NewLine);
 136                         return sb.ToString ();
 137                 }
 138         }
 139 }