protected virtual PkixCertPathBuilderResult Build(
X509Certificate tbvCert,
PkixBuilderParameters pkixParams,
IList tbvPath)
{
// If tbvCert is readily present in tbvPath, it indicates having run
// into a cycle in the PKI graph.
if (tbvPath.Contains(tbvCert))
{
return(null);
}
// step out, the certificate is not allowed to appear in a certification
// chain.
if (pkixParams.GetExcludedCerts().Contains(tbvCert))
{
return(null);
}
// test if certificate path exceeds maximum length
if (pkixParams.MaxPathLength != -1)
{
if (tbvPath.Count - 1 > pkixParams.MaxPathLength)
{
return(null);
}
}
tbvPath.Add(tbvCert);
// X509CertificateParser certParser = new X509CertificateParser();
PkixCertPathBuilderResult builderResult = null;
PkixCertPathValidator validator = new PkixCertPathValidator();
try
{
// check whether the issuer of <tbvCert> is a TrustAnchor
if (PkixCertPathValidatorUtilities.FindTrustAnchor(tbvCert, pkixParams.GetTrustAnchors()) != null)
{
// exception message from possibly later tried certification
// chains
PkixCertPath certPath = null;
try
{
certPath = new PkixCertPath(tbvPath);
}
catch (Exception e)
{
throw new Exception(
"Certification path could not be constructed from certificate list.",
e);
}
PkixCertPathValidatorResult result = null;
try
{
result = (PkixCertPathValidatorResult)validator.Validate(
certPath, pkixParams);
}
catch (Exception e)
{
throw new Exception(
"Certification path could not be validated.", e);
}
return(new PkixCertPathBuilderResult(certPath, result.TrustAnchor,
result.PolicyTree, result.SubjectPublicKey));
}
else
{
// add additional X.509 stores from locations in certificate
try
{
PkixCertPathValidatorUtilities.AddAdditionalStoresFromAltNames(
tbvCert, pkixParams);
}
catch (CertificateParsingException e)
{
throw new Exception(
"No additiontal X.509 stores can be added from certificate locations.",
e);
}
// try to get the issuer certificate from one of the stores
HashSet issuers = new HashSet();
try
{
issuers.AddAll(PkixCertPathValidatorUtilities.FindIssuerCerts(tbvCert, pkixParams));
}
catch (Exception e)
{
throw new Exception(
"Cannot find issuer certificate for certificate in certification path.",
e);
}
if (issuers.IsEmpty)
{
throw new Exception("No issuer certificate for certificate in certification path found.");
}
foreach (X509Certificate issuer in issuers)
{
builderResult = Build(issuer, pkixParams, tbvPath);
if (builderResult != null)
{
break;
}
}
}
}
catch (Exception e)
{
certPathException = e;
}
if (builderResult == null)
{
tbvPath.Remove(tbvCert);
}
return(builderResult);
}
/**
* Searches for a holder public key certificate and verifies its
* certification path.
*
* @param attrCert the attribute certificate.
* @param pkixParams The PKIX parameters.
* @return The certificate path of the holder certificate.
* @throws Exception if
* <ul>
* <li>no public key certificate can be found although holder
* information is given by an entity name or a base certificate
* ID</li>
* <li>support classes cannot be created</li>
* <li>no certification path for the public key certificate can
* be built</li>
* </ul>
*/
internal static PkixCertPath ProcessAttrCert1(
IX509AttributeCertificate attrCert,
PkixParameters pkixParams)
{
PkixCertPathBuilderResult result = null;
// find holder PKCs
ISet holderPKCs = new HashSet();
if (attrCert.Holder.GetIssuer() != null)
{
X509CertStoreSelector selector = new X509CertStoreSelector();
selector.SerialNumber = attrCert.Holder.SerialNumber;
X509Name[] principals = attrCert.Holder.GetIssuer();
for (int i = 0; i < principals.Length; i++)
{
try
{
// if (principals[i] is X500Principal)
{
selector.Issuer = principals[i];
}
holderPKCs.AddAll(PkixCertPathValidatorUtilities
.FindCertificates(selector, pkixParams.GetStores()));
}
catch (Exception e)
{
throw new PkixCertPathValidatorException(
"Public key certificate for attribute certificate cannot be searched.",
e);
}
}
if (holderPKCs.IsEmpty)
{
throw new PkixCertPathValidatorException(
"Public key certificate specified in base certificate ID for attribute certificate cannot be found.");
}
}
if (attrCert.Holder.GetEntityNames() != null)
{
X509CertStoreSelector selector = new X509CertStoreSelector();
X509Name[] principals = attrCert.Holder.GetEntityNames();
for (int i = 0; i < principals.Length; i++)
{
try
{
// if (principals[i] is X500Principal)
{
selector.Issuer = principals[i];
}
holderPKCs.AddAll(PkixCertPathValidatorUtilities
.FindCertificates(selector, pkixParams.GetStores()));
}
catch (Exception e)
{
throw new PkixCertPathValidatorException(
"Public key certificate for attribute certificate cannot be searched.",
e);
}
}
if (holderPKCs.IsEmpty)
{
throw new PkixCertPathValidatorException(
"Public key certificate specified in entity name for attribute certificate cannot be found.");
}
}
// verify cert paths for PKCs
PkixBuilderParameters parameters = (PkixBuilderParameters)
PkixBuilderParameters.GetInstance(pkixParams);
PkixCertPathValidatorException lastException = null;
foreach (X509Certificate cert in holderPKCs)
{
X509CertStoreSelector selector = new X509CertStoreSelector();
selector.Certificate = cert;
parameters.SetTargetConstraints(selector);
PkixCertPathBuilder builder = new PkixCertPathBuilder();
try
{
result = builder.Build(PkixBuilderParameters.GetInstance(parameters));
}
catch (PkixCertPathBuilderException e)
{
lastException = new PkixCertPathValidatorException(
"Certification path for public key certificate of attribute certificate could not be build.",
e);
}
}
if (lastException != null)
{
throw lastException;
}
return(result.CertPath);
}