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 // (C) 2004 Novell (http://www.novell.com)
   9 //
  10
  11 using System;
  12 using System.Globalization;
  13 using System.Text;
  14
  15 using Mono.Security;
  16 using Mono.Security.X509;
  17
  18 namespace Mono.Security.X509.Extensions {
  19
  20         // References:
  21         // 1.   RFC 3280: Internet X.509 Public Key Infrastructure, Section 4.2.1.10
  22         //      http://www.ietf.org/rfc/rfc3280.txt
  23
  24         /* id-ce-basicConstraints OBJECT IDENTIFIER ::=  { id-ce 19 }
  25          *
  26          * BasicConstraints ::= SEQUENCE {
  27          *      cA                      BOOLEAN DEFAULT FALSE,
  28          *      pathLenConstraint       INTEGER (0..MAX) OPTIONAL
  29          * }
  30          */
  31 #if INSIDE_CORLIB
  32         internal
  33 #else
  34         public
  35 #endif
  36         class BasicConstraintsExtension : X509Extension {
  37
  38                 private bool cA;
  39                 private int pathLenConstraint;
  40
  41                 public BasicConstraintsExtension () : base ()
  42                 {
  43                         extnOid = "2.5.29.19";
  44                 }
  45
  46                 public BasicConstraintsExtension (ASN1 asn1) : base (asn1) {}
  47
  48                 public BasicConstraintsExtension (X509Extension extension) : base (extension) {}
  49
  50                 protected override void Decode ()
  51                 {
  52                         // default values
  53                         cA = false;
  54                         pathLenConstraint = 0; // no constraint
  55
  56                         ASN1 sequence = new ASN1 (extnValue.Value);
  57                         if (sequence.Tag != 0x30)
  58                                 throw new ArgumentException ("Invalid BasicConstraints extension");
  59                         int n = 0;
  60                         ASN1 a = sequence [n++];
  61                         if ((a != null) && (a.Tag == 0x01)) {
  62                                 cA = (a.Value [0] == 0xFF);
  63                                 a = sequence [n++];
  64                         }
  65                         if ((a != null) && (a.Tag == 0x02))
  66                                 pathLenConstraint = ASN1Convert.ToInt32 (a);
  67                 }
  68
  69                 protected override void Encode ()
  70                 {
  71                         if (extnValue == null) {
  72                                 extnValue = new ASN1 (0x30);
  73                                 if (cA)
  74                                         extnValue.Add (new ASN1 (0x01, new byte[] { 0xFF }));
  75                                 if (pathLenConstraint > 0)
  76                                         extnValue.Add (ASN1Convert.FromInt32 (pathLenConstraint));
  77                         }
  78                 }
  79
  80                 public bool CertificateAuthority {
  81                         get { return cA; }
  82                         set { cA = value; }
  83                 }
  84
  85                 public override string Name {
  86                         get { return "Basic Constraints"; }
  87                 }
  88
  89                 public int PathLenConstraint {
  90                         get { return pathLenConstraint; }
  91                         set { pathLenConstraint = value; }
  92                 }
  93
  94                 public override string ToString ()
  95                 {
  96                         StringBuilder sb = new StringBuilder ();
  97                         sb.Append ("Subject Type=");
  98                         sb.Append ((cA) ? "CA" : "End Entity");
  99                         sb.Append (Environment.NewLine);
 100                         sb.Append ("Path Length Constraint=");
 101                         if (pathLenConstraint == 0)
 102                                 sb.Append ("None");
 103                         else
 104                                 sb.Append (pathLenConstraint.ToString (CultureInfo.InvariantCulture));
 105                         sb.Append (Environment.NewLine);
 106                         return sb.ToString ();
 107                 }
 108         }
 109 }