private bool CheckClientCertificateExtensions(X509Certificate cert)
{
KeyUsages ku = KeyUsages.digitalSignature | KeyUsages.keyEncipherment | KeyUsages.keyAgreement;
KeyUsageExtension kux = null;
ExtendedKeyUsageExtension eku = null;
X509Extension xtn = cert.Extensions["2.5.29.15"];
if (xtn != null)
kux = new KeyUsageExtension (xtn);
xtn = cert.Extensions["2.5.29.37"];
if (xtn != null)
eku = new ExtendedKeyUsageExtension (xtn);
if ((kux != null) && (eku != null)) {
// RFC3280 states that when both KeyUsageExtension and
// ExtendedKeyUsageExtension are present then BOTH should
// be valid
return (kux.Support (ku) &&
eku.KeyPurpose.Contains ("1.3.6.1.5.5.7.3.2"));
} else if (kux != null) {
return kux.Support (ku);
} else if (eku != null) {
// Client Authentication (1.3.6.1.5.5.7.3.2)
return eku.KeyPurpose.Contains ("1.3.6.1.5.5.7.3.2");
}
// last chance - try with older (deprecated) Netscape extensions
xtn = cert.Extensions["2.16.840.1.113730.1.1"];
if (xtn != null) {
NetscapeCertTypeExtension ct = new NetscapeCertTypeExtension (xtn);
return ct.Support (NetscapeCertTypeExtension.CertTypes.SslClient);
}
// certificate isn't valid for SSL client usage
return false;
}
bool NetscapeCertType(MSX.PKCS12 pfx)
{
foreach (MSX.X509Certificate cert in pfx.Certificates) {
MSX.X509Extension xtn = cert.Extensions ["2.16.840.1.113730.1.1"];
if (xtn == null)
continue;
var ct = new NetscapeCertTypeExtension (xtn);
if (!ct.Support (NetscapeCertTypeExtension.CertTypes.SslServer))
continue;
key = GetKeyMatchingCertificate (pfx, cert);
if (key == null)
continue;
x509 = new X509Certificate (cert.RawData);
break;
}
// complete ?
return ((x509 != null) && (key != null));
}
// Note: this method only works for RSA certificates
// DH certificates requires some changes - does anyone use one ?
private bool checkCertificateUsage (X509Certificate cert)
{
ClientContext context = (ClientContext)this.Context;
// certificate extensions are required for this
// we "must" accept older certificates without proofs
if (cert.Version < 3)
return true;
KeyUsages ku = KeyUsages.none;
switch (context.Negotiating.Cipher.ExchangeAlgorithmType)
{
case ExchangeAlgorithmType.RsaSign:
ku = KeyUsages.digitalSignature;
break;
case ExchangeAlgorithmType.RsaKeyX:
ku = KeyUsages.keyEncipherment;
break;
case ExchangeAlgorithmType.DiffieHellman:
ku = KeyUsages.keyAgreement;
break;
case ExchangeAlgorithmType.Fortezza:
return false; // unsupported certificate type
}
KeyUsageExtension kux = null;
ExtendedKeyUsageExtension eku = null;
X509Extension xtn = cert.Extensions ["2.5.29.15"];
if (xtn != null)
kux = new KeyUsageExtension (xtn);
xtn = cert.Extensions ["2.5.29.37"];
if (xtn != null)
eku = new ExtendedKeyUsageExtension (xtn);
if ((kux != null) && (eku != null))
{
// RFC3280 states that when both KeyUsageExtension and
// ExtendedKeyUsageExtension are present then BOTH should
// be valid
if (!kux.Support (ku))
return false;
return (eku.KeyPurpose.Contains ("1.3.6.1.5.5.7.3.1") ||
eku.KeyPurpose.Contains ("2.16.840.1.113730.4.1"));
}
else if (kux != null)
{
return kux.Support (ku);
}
else if (eku != null)
{
// Server Authentication (1.3.6.1.5.5.7.3.1) or
// Netscape Server Gated Crypto (2.16.840.1.113730.4)
return (eku.KeyPurpose.Contains ("1.3.6.1.5.5.7.3.1") ||
eku.KeyPurpose.Contains ("2.16.840.1.113730.4.1"));
}
// last chance - try with older (deprecated) Netscape extensions
xtn = cert.Extensions ["2.16.840.1.113730.1.1"];
if (xtn != null)
{
NetscapeCertTypeExtension ct = new NetscapeCertTypeExtension (xtn);
return ct.Support (NetscapeCertTypeExtension.CertTypes.SslServer);
}
// if the CN=host (checked later) then we assume this is meant for SSL/TLS
// e.g. the new smtp.gmail.com certificate
return true;
}
private bool checkCertificateUsage (X509Certificate cert)
{
ServerContext context = (ServerContext)this.Context;
// certificate extensions are required for this
// we "must" accept older certificates without proofs
if (cert.Version < 3)
return true;
KeyUsages ku = KeyUsages.none;
switch (context.Negotiating.Cipher.ExchangeAlgorithmType)
{
case ExchangeAlgorithmType.RsaSign:
case ExchangeAlgorithmType.RsaKeyX:
ku = KeyUsages.digitalSignature;
break;
case ExchangeAlgorithmType.DiffieHellman:
ku = KeyUsages.keyAgreement;
break;
case ExchangeAlgorithmType.Fortezza:
return false; // unsupported certificate type
}
KeyUsageExtension kux = null;
ExtendedKeyUsageExtension eku = null;
X509Extension xtn = cert.Extensions["2.5.29.15"];
if (xtn != null)
kux = new KeyUsageExtension (xtn);
xtn = cert.Extensions["2.5.29.37"];
if (xtn != null)
eku = new ExtendedKeyUsageExtension (xtn);
if ((kux != null) && (eku != null))
{
// RFC3280 states that when both KeyUsageExtension and
// ExtendedKeyUsageExtension are present then BOTH should
// be valid
return (kux.Support (ku) &&
eku.KeyPurpose.Contains ("1.3.6.1.5.5.7.3.2"));
}
else if (kux != null)
{
return kux.Support (ku);
}
else if (eku != null)
{
// Client Authentication (1.3.6.1.5.5.7.3.2)
return eku.KeyPurpose.Contains ("1.3.6.1.5.5.7.3.2");
}
// last chance - try with older (deprecated) Netscape extensions
xtn = cert.Extensions["2.16.840.1.113730.1.1"];
if (xtn != null)
{
NetscapeCertTypeExtension ct = new NetscapeCertTypeExtension (xtn);
return ct.Support (NetscapeCertTypeExtension.CertTypes.SslClient);
}
// certificate isn't valid for SSL server usage
return false;
}
