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//
// KeyUsageExtension.cs: Handles X.509 KeyUsage extensions.
//
// Author:
// Sebastien Pouliot <sebastien@ximian.com>
//
// (C) 2003 Motus Technologies Inc. (http://www.motus.com)
// Copyright (C) 2004-2005 Novell, Inc (http://www.novell.com)
//
// Permission is hereby granted, free of charge, to any person obtaining
// a copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to
// permit persons to whom the Software is furnished to do so, subject to
// the following conditions:
//
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//
using System;
using System.Globalization;
using System.Text;
using Mono.Security;
using Mono.Security.X509;
namespace Mono.Security.X509.Extensions {
/*
* id-ce-keyUsage OBJECT IDENTIFIER ::= { id-ce 15 }
*
* KeyUsage ::= BIT STRING {
* digitalSignature (0),
* nonRepudiation (1),
* keyEncipherment (2),
* dataEncipherment (3),
* keyAgreement (4),
* keyCertSign (5),
* cRLSign (6),
* encipherOnly (7),
* decipherOnly (8)
* }
*/
// note: because nothing is simple in ASN.1 bits are reversed
[Flags]
#if INSIDE_CORLIB || INSIDE_SYSTEM
internal
#else
public
#endif
enum KeyUsages {
digitalSignature = 0x80,
nonRepudiation = 0x40,
keyEncipherment = 0x20,
dataEncipherment = 0x10,
keyAgreement = 0x08,
keyCertSign = 0x04,
cRLSign = 0x02,
encipherOnly = 0x01,
decipherOnly = 0x800,
none = 0x0
}
#if INSIDE_CORLIB || INSIDE_SYSTEM
internal
#else
public
#endif
class KeyUsageExtension : X509Extension {
private int kubits;
public KeyUsageExtension (ASN1 asn1) : base (asn1) {}
public KeyUsageExtension (X509Extension extension) : base (extension) {}
public KeyUsageExtension () : base ()
{
extnOid = "2.5.29.15";
}
protected override void Decode ()
{
ASN1 bitString = new ASN1 (extnValue.Value);
if (bitString.Tag != 0x03)
throw new ArgumentException ("Invalid KeyUsage extension");
int i = 1; // byte zero has the number of unused bits (ASN1's BITSTRING)
while (i < bitString.Value.Length)
kubits = (kubits << 8) + bitString.Value [i++];
}
protected override void Encode ()
{
extnValue = new ASN1 (0x04);
ushort ku = (ushort) kubits;
byte unused = 16;
if (ku > 0) {
// count the unused bits
for (unused = 15; unused > 0; unused--) {
if ((ku & 0x8000) == 0x8000)
break;
ku <<= 1;
}
if (kubits > Byte.MaxValue) {
unused -= 8;
extnValue.Add (new ASN1 (0x03, new byte[] { unused, (byte) kubits, (byte) (kubits >> 8) }));
} else {
extnValue.Add (new ASN1 (0x03, new byte[] { unused, (byte) kubits }));
}
} else {
// note: a BITSTRING with a 0 length is invalid (in ASN.1), so would an
// empty OCTETSTRING (at the parent level) so we're encoding a 0
extnValue.Add (new ASN1 (0x03, new byte[] { 7, 0 }));
}
}
public KeyUsages KeyUsage {
get { return (KeyUsages) kubits; }
set { kubits = Convert.ToInt32 (value, CultureInfo.InvariantCulture); }
}
public override string Name {
get { return "Key Usage"; }
}
public bool Support (KeyUsages usage)
{
int x = Convert.ToInt32 (usage, CultureInfo.InvariantCulture);
return ((x & kubits) == x);
}
public override string ToString ()
{
const string separator = " , ";
StringBuilder sb = new StringBuilder ();
if (Support (KeyUsages.digitalSignature))
sb.Append ("Digital Signature");
if (Support (KeyUsages.nonRepudiation)) {
if (sb.Length > 0)
sb.Append (separator);
sb.Append ("Non-Repudiation");
}
if (Support (KeyUsages.keyEncipherment)) {
if (sb.Length > 0)
sb.Append (separator);
sb.Append ("Key Encipherment");
}
if (Support (KeyUsages.dataEncipherment)) {
if (sb.Length > 0)
sb.Append (separator);
sb.Append ("Data Encipherment");
}
if (Support (KeyUsages.keyAgreement)) {
if (sb.Length > 0)
sb.Append (separator);
sb.Append ("Key Agreement");
}
if (Support (KeyUsages.keyCertSign)) {
if (sb.Length > 0)
sb.Append (separator);
sb.Append ("Certificate Signing");
}
if (Support (KeyUsages.cRLSign)) {
if (sb.Length > 0)
sb.Append (separator);
sb.Append ("CRL Signing");
}
if (Support (KeyUsages.encipherOnly)) {
if (sb.Length > 0)
sb.Append (separator);
sb.Append ("Encipher Only "); // ???
}
if (Support (KeyUsages.decipherOnly)) {
if (sb.Length > 0)
sb.Append (separator);
sb.Append ("Decipher Only"); // ???
}
sb.Append ("(");
sb.Append (kubits.ToString ("X2", CultureInfo.InvariantCulture));
sb.Append (")");
sb.Append (Environment.NewLine);
return sb.ToString ();
}
}
}
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