private PkixCertPathBuilderResult Build(
IX509AttributeCertificate attrCert,
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);
PkixCertPathBuilderResult builderResult = null;
// X509CertificateParser certParser = new X509CertificateParser();
PkixAttrCertPathValidator validator = new PkixAttrCertPathValidator();
try
{
// check whether the issuer of <tbvCert> is a TrustAnchor
if (PkixCertPathValidatorUtilities.FindTrustAnchor(tbvCert, pkixParams.GetTrustAnchors()) != null)
{
PkixCertPath certPath = new PkixCertPath(tbvPath);
PkixCertPathValidatorResult result;
try
{
result = 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 additional X.509 stores can be added from certificate locations.", e);
}
// try to get the issuer certificate from one of the stores
ISet 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)
{
// if untrusted self signed certificate continue
if (PkixCertPathValidatorUtilities.IsSelfIssued(issuer))
{
continue;
}
builderResult = Build(attrCert, issuer, pkixParams, tbvPath);
if (builderResult != null)
{
break;
}
}
}
}
catch (Exception e)
{
certPathException = new Exception("No valid certification path could be build.", e);
}
if (builderResult == null)
{
tbvPath.Remove(tbvCert);
}
return(builderResult);
}
public virtual PkixCertPathValidatorResult Validate(
PkixCertPath certPath,
PkixParameters paramsPkix)
{
if (paramsPkix.GetTrustAnchors() == null)
{
throw new ArgumentException(
"trustAnchors is null, this is not allowed for certification path validation.",
"parameters");
}
//
// 6.1.1 - inputs
//
//
// (a)
//
IList certs = certPath.Certificates;
int n = certs.Count;
if (certs.Count == 0)
{
throw new PkixCertPathValidatorException("Certification path is empty.", null, certPath, 0);
}
//
// (b)
//
// DateTime validDate = PkixCertPathValidatorUtilities.GetValidDate(paramsPkix);
//
// (c)
//
ISet userInitialPolicySet = paramsPkix.GetInitialPolicies();
//
// (d)
//
TrustAnchor trust;
try
{
trust = PkixCertPathValidatorUtilities.FindTrustAnchor(
(X509Certificate)certs[certs.Count - 1],
paramsPkix.GetTrustAnchors());
}
catch (Exception e)
{
throw new PkixCertPathValidatorException(e.Message, e, certPath, certs.Count - 1);
}
if (trust == null)
{
throw new PkixCertPathValidatorException("Trust anchor for certification path not found.", null, certPath, -1);
}
//
// (e), (f), (g) are part of the paramsPkix object.
//
IEnumerator certIter;
int index = 0;
int i;
// Certificate for each interation of the validation loop
// Signature information for each iteration of the validation loop
//
// 6.1.2 - setup
//
//
// (a)
//
IList[] policyNodes = new IList[n + 1];
for (int j = 0; j < policyNodes.Length; j++)
{
policyNodes[j] = Platform.CreateArrayList();
}
ISet policySet = new HashSet();
policySet.Add(Rfc3280CertPathUtilities.ANY_POLICY);
PkixPolicyNode validPolicyTree = new PkixPolicyNode(Platform.CreateArrayList(), 0, policySet, null, new HashSet(),
Rfc3280CertPathUtilities.ANY_POLICY, false);
policyNodes[0].Add(validPolicyTree);
//
// (b) and (c)
//
PkixNameConstraintValidator nameConstraintValidator = new PkixNameConstraintValidator();
// (d)
//
int explicitPolicy;
ISet acceptablePolicies = new HashSet();
if (paramsPkix.IsExplicitPolicyRequired)
{
explicitPolicy = 0;
}
else
{
explicitPolicy = n + 1;
}
//
// (e)
//
int inhibitAnyPolicy;
if (paramsPkix.IsAnyPolicyInhibited)
{
inhibitAnyPolicy = 0;
}
else
{
inhibitAnyPolicy = n + 1;
}
//
// (f)
//
int policyMapping;
if (paramsPkix.IsPolicyMappingInhibited)
{
policyMapping = 0;
}
else
{
policyMapping = n + 1;
}
//
// (g), (h), (i), (j)
//
AsymmetricKeyParameter workingPublicKey;
X509Name workingIssuerName;
X509Certificate sign = trust.TrustedCert;
try
{
if (sign != null)
{
workingIssuerName = sign.SubjectDN;
workingPublicKey = sign.GetPublicKey();
}
else
{
workingIssuerName = new X509Name(trust.CAName);
workingPublicKey = trust.CAPublicKey;
}
}
catch (ArgumentException ex)
{
throw new PkixCertPathValidatorException("Subject of trust anchor could not be (re)encoded.", ex, certPath,
-1);
}
AlgorithmIdentifier workingAlgId = null;
try
{
workingAlgId = PkixCertPathValidatorUtilities.GetAlgorithmIdentifier(workingPublicKey);
}
catch (PkixCertPathValidatorException e)
{
throw new PkixCertPathValidatorException(
"Algorithm identifier of public key of trust anchor could not be read.", e, certPath, -1);
}
// DerObjectIdentifier workingPublicKeyAlgorithm = workingAlgId.Algorithm;
// Asn1Encodable workingPublicKeyParameters = workingAlgId.Parameters;
//
// (k)
//
int maxPathLength = n;
//
// 6.1.3
//
X509CertStoreSelector certConstraints = paramsPkix.GetTargetCertConstraints();
if (certConstraints != null && !certConstraints.Match((X509Certificate)certs[0]))
{
throw new PkixCertPathValidatorException(
"Target certificate in certification path does not match targetConstraints.", null, certPath, 0);
}
//
// initialize CertPathChecker's
//
IList pathCheckers = paramsPkix.GetCertPathCheckers();
certIter = pathCheckers.GetEnumerator();
while (certIter.MoveNext())
{
((PkixCertPathChecker)certIter.Current).Init(false);
}
X509Certificate cert = null;
for (index = certs.Count - 1; index >= 0; index--)
{
// try
// {
//
// i as defined in the algorithm description
//
i = n - index;
//
// set certificate to be checked in this round
// sign and workingPublicKey and workingIssuerName are set
// at the end of the for loop and initialized the
// first time from the TrustAnchor
//
cert = (X509Certificate)certs[index];
//
// 6.1.3
//
Rfc3280CertPathUtilities.ProcessCertA(certPath, paramsPkix, index, workingPublicKey,
workingIssuerName, sign);
Rfc3280CertPathUtilities.ProcessCertBC(certPath, index, nameConstraintValidator);
validPolicyTree = Rfc3280CertPathUtilities.ProcessCertD(certPath, index,
acceptablePolicies, validPolicyTree, policyNodes, inhibitAnyPolicy);
validPolicyTree = Rfc3280CertPathUtilities.ProcessCertE(certPath, index, validPolicyTree);
Rfc3280CertPathUtilities.ProcessCertF(certPath, index, validPolicyTree, explicitPolicy);
//
// 6.1.4
//
if (i != n)
{
if (cert != null && cert.Version == 1)
{
throw new PkixCertPathValidatorException(
"Version 1 certificates can't be used as CA ones.", null, certPath, index);
}
Rfc3280CertPathUtilities.PrepareNextCertA(certPath, index);
validPolicyTree = Rfc3280CertPathUtilities.PrepareCertB(certPath, index, policyNodes,
validPolicyTree, policyMapping);
Rfc3280CertPathUtilities.PrepareNextCertG(certPath, index, nameConstraintValidator);
// (h)
explicitPolicy = Rfc3280CertPathUtilities.PrepareNextCertH1(certPath, index, explicitPolicy);
policyMapping = Rfc3280CertPathUtilities.PrepareNextCertH2(certPath, index, policyMapping);
inhibitAnyPolicy = Rfc3280CertPathUtilities.PrepareNextCertH3(certPath, index, inhibitAnyPolicy);
//
// (i)
//
explicitPolicy = Rfc3280CertPathUtilities.PrepareNextCertI1(certPath, index, explicitPolicy);
policyMapping = Rfc3280CertPathUtilities.PrepareNextCertI2(certPath, index, policyMapping);
// (j)
inhibitAnyPolicy = Rfc3280CertPathUtilities.PrepareNextCertJ(certPath, index, inhibitAnyPolicy);
// (k)
Rfc3280CertPathUtilities.PrepareNextCertK(certPath, index);
// (l)
maxPathLength = Rfc3280CertPathUtilities.PrepareNextCertL(certPath, index, maxPathLength);
// (m)
maxPathLength = Rfc3280CertPathUtilities.PrepareNextCertM(certPath, index, maxPathLength);
// (n)
Rfc3280CertPathUtilities.PrepareNextCertN(certPath, index);
ISet criticalExtensions1 = cert.GetCriticalExtensionOids();
if (criticalExtensions1 != null)
{
criticalExtensions1 = new HashSet(criticalExtensions1);
// these extensions are handled by the algorithm
criticalExtensions1.Remove(X509Extensions.KeyUsage.Id);
criticalExtensions1.Remove(X509Extensions.CertificatePolicies.Id);
criticalExtensions1.Remove(X509Extensions.PolicyMappings.Id);
criticalExtensions1.Remove(X509Extensions.InhibitAnyPolicy.Id);
criticalExtensions1.Remove(X509Extensions.IssuingDistributionPoint.Id);
criticalExtensions1.Remove(X509Extensions.DeltaCrlIndicator.Id);
criticalExtensions1.Remove(X509Extensions.PolicyConstraints.Id);
criticalExtensions1.Remove(X509Extensions.BasicConstraints.Id);
criticalExtensions1.Remove(X509Extensions.SubjectAlternativeName.Id);
criticalExtensions1.Remove(X509Extensions.NameConstraints.Id);
}
else
{
criticalExtensions1 = new HashSet();
}
// (o)
Rfc3280CertPathUtilities.PrepareNextCertO(certPath, index, criticalExtensions1, pathCheckers);
// set signing certificate for next round
sign = cert;
// (c)
workingIssuerName = sign.SubjectDN;
// (d)
try
{
workingPublicKey = PkixCertPathValidatorUtilities.GetNextWorkingKey(certPath.Certificates, index);
}
catch (PkixCertPathValidatorException e)
{
throw new PkixCertPathValidatorException("Next working key could not be retrieved.", e, certPath, index);
}
workingAlgId = PkixCertPathValidatorUtilities.GetAlgorithmIdentifier(workingPublicKey);
// (f)
// workingPublicKeyAlgorithm = workingAlgId.Algorithm;
// (e)
// workingPublicKeyParameters = workingAlgId.Parameters;
}
}
//
// 6.1.5 Wrap-up procedure
//
explicitPolicy = Rfc3280CertPathUtilities.WrapupCertA(explicitPolicy, cert);
explicitPolicy = Rfc3280CertPathUtilities.WrapupCertB(certPath, index + 1, explicitPolicy);
//
// (c) (d) and (e) are already done
//
//
// (f)
//
ISet criticalExtensions = cert.GetCriticalExtensionOids();
if (criticalExtensions != null)
{
criticalExtensions = new HashSet(criticalExtensions);
// Requires .Id
// these extensions are handled by the algorithm
criticalExtensions.Remove(X509Extensions.KeyUsage.Id);
criticalExtensions.Remove(X509Extensions.CertificatePolicies.Id);
criticalExtensions.Remove(X509Extensions.PolicyMappings.Id);
criticalExtensions.Remove(X509Extensions.InhibitAnyPolicy.Id);
criticalExtensions.Remove(X509Extensions.IssuingDistributionPoint.Id);
criticalExtensions.Remove(X509Extensions.DeltaCrlIndicator.Id);
criticalExtensions.Remove(X509Extensions.PolicyConstraints.Id);
criticalExtensions.Remove(X509Extensions.BasicConstraints.Id);
criticalExtensions.Remove(X509Extensions.SubjectAlternativeName.Id);
criticalExtensions.Remove(X509Extensions.NameConstraints.Id);
criticalExtensions.Remove(X509Extensions.CrlDistributionPoints.Id);
}
else
{
criticalExtensions = new HashSet();
}
Rfc3280CertPathUtilities.WrapupCertF(certPath, index + 1, pathCheckers, criticalExtensions);
PkixPolicyNode intersection = Rfc3280CertPathUtilities.WrapupCertG(certPath, paramsPkix, userInitialPolicySet,
index + 1, policyNodes, validPolicyTree, acceptablePolicies);
if ((explicitPolicy > 0) || (intersection != null))
{
return(new PkixCertPathValidatorResult(trust, intersection, cert.GetPublicKey()));
}
throw new PkixCertPathValidatorException("Path processing failed on policy.", null, certPath, index);
}