public Task <(bool isValid, AcmeError?error)> ValidateCsrAsync(Order order, string csr, CancellationToken cancellationToken)
{
try
{
var request = new CertEnroll.CX509CertificateRequestPkcs10();
request.InitializeDecode(csr, CertEnroll.EncodingType.XCN_CRYPT_STRING_BASE64);
request.CheckSignature();
if (!SubjectIsValid(request, order))
{
return(Task.FromResult((false, (AcmeError?)new AcmeError("badCSR", "CN Invalid."))));
}
if (!SubjectAlternateNamesAreValid(request, order))
{
return(Task.FromResult((false, (AcmeError?)new AcmeError("badCSR", "SAN Invalid."))));
}
return(Task.FromResult((true, (AcmeError?)null)));
}
catch (Exception ex)
{
_logger.LogWarning(ex.ToString());
}
return(Task.FromResult((false, (AcmeError?)new AcmeError("badCSR", "CSR could not be read."))));
}
public Task <(bool isValid, AcmeError?error)> ValidateCsrAsync(Order order, string csr, CancellationToken cancellationToken)
{
_logger.LogDebug($"Attempting validation of CSR {csr}");
try
{
var request = new CertEnroll.CX509CertificateRequestPkcs10();
request.InitializeDecode(csr, CertEnroll.EncodingType.XCN_CRYPT_STRING_BASE64);
request.CheckSignature();
if (!SubjectIsValid(request, order))
{
_logger.LogDebug("CSR Validation failed due to invalid CN.");
return(Task.FromResult((false, (AcmeError?)new AcmeError("badCSR", "CN Invalid."))));
}
if (!SubjectAlternateNamesAreValid(request, order))
{
_logger.LogDebug("CSR Validation failed due to invalid SAN.");
return(Task.FromResult((false, (AcmeError?)new AcmeError("badCSR", "SAN Invalid."))));
}
_logger.LogDebug("CSR Validation succeeded.");
return(Task.FromResult((true, (AcmeError?)null)));
}
catch (Exception ex)
{
_logger.LogWarning(ex, $"Validation of CSR failed with exception.");
return(Task.FromResult((false, (AcmeError?)new AcmeError("badCSR", "CSR could not be read."))));
}
}
private bool SubjectIsValid(CertEnroll.CX509CertificateRequestPkcs10 request, Order order)
{
var validCNs = order.Identifiers.Select(x => x.Value)
.Concat(order.Identifiers.Where(x => x.IsWildcard).Select(x => x.Value.Substring(2)))
.Select(x => "CN=" + x)
.ToList();
return(validCNs.Any(x => request.Subject.Name.Equals(x) ||
(_options.Value.AllowCNSuffix && request.Subject.Name.StartsWith(x))));
}
private bool SubjectAlternateNamesAreValid(CertEnroll.CX509CertificateRequestPkcs10 request, Order order)
{
try
{
var identifiers = order.Identifiers.Select(x => x.Value).ToList();
foreach (var x509Ext in request.X509Extensions.Cast <CertEnroll.CX509Extension>())
{
if (x509Ext.ObjectId.Name != CertEnroll.CERTENROLL_OBJECTID.XCN_OID_SUBJECT_ALT_NAME2)
{
return(false);
}
var extBase64 = x509Ext.RawData[CertEnroll.EncodingType.XCN_CRYPT_STRING_BASE64];
if (string.IsNullOrWhiteSpace(extBase64))
{
return(false);
}
var sanNames = new CertEnroll.CX509ExtensionAlternativeNames();
sanNames.InitializeDecode(CertEnroll.EncodingType.XCN_CRYPT_STRING_BASE64, extBase64);
foreach (var san in sanNames.AlternativeNames.Cast <CertEnroll.CAlternativeName>())
{
if (san.Type != CertEnroll.AlternativeNameType.XCN_CERT_ALT_NAME_DNS_NAME)
{
return(false);
}
if (!identifiers.Contains(san.strValue))
{
return(false);
}
}
}
return(true);
}
catch (Exception ex)
{
_logger.LogError(ex, "Error occured during validation of CSR.");
return(false);
}
}
private bool SubjectIsValid(CertEnroll.CX509CertificateRequestPkcs10 request, Order order)
{
try
{
var validCNs = order.Identifiers.Select(x => x.Value)
.Concat(order.Identifiers.Where(x => x.IsWildcard).Select(x => x.Value.Substring(2)))
.Select(x => "CN=" + x)
.ToList();
return(validCNs.Any(x => request.Subject.Name.Equals(x) ||
(_options.Value.AllowCNSuffix && request.Subject.Name.StartsWith(x))));
}
// This is thrown, if there is no subject.
catch (Exception ex)
{
_logger.LogError(ex, "Error occured during validation of CSR Subject.");
return(_options.Value.AllowEmptyCN);
}
}