private void RebuildExtensions()
{
if (_frozen)
{
return;
}
Marshal.FreeHGlobal(_blob);
var structSize = Marshal.SizeOf(typeof(CERT_EXTENSION));
_blob = Marshal.AllocHGlobal(structSize * _marshaledExtensions.Count);
for (int index = 0, offset = 0; index < _marshaledExtensions.Count; index++, offset += structSize)
{
var marshalX509Extension = _marshaledExtensions[index];
Marshal.StructureToPtr(marshalX509Extension.Value, IntPtrArithmetic.Add(_blob, offset), false);
}
}
private static byte[] EncodeExtension(IList <X509AlternativeName> altNames)
{
var certAltName = new CERT_ALT_NAME_INFO();
certAltName.cAltEntry = (uint)altNames.Count;
var structSize = Marshal.SizeOf(typeof(CERT_ALT_NAME_ENTRY));
var altNamesBuffer = Marshal.AllocHGlobal(structSize * altNames.Count);
var unionValues = new List <IntPtr>();
try
{
for (int index = 0, offset = 0; index < altNames.Count; index++, offset += structSize)
{
var altName = new CERT_ALT_NAME_ENTRY();
altName.dwAltNameChoice = (CertAltNameChoice)altNames[index].Type;
switch (altName.dwAltNameChoice)
{
case CertAltNameChoice.CERT_ALT_NAME_DNS_NAME:
altName.Value = new CERT_ALT_NAME_ENTRY_UNION
{
pwszDNSName = Marshal.StringToHGlobalUni((string)altNames[index].Value)
};
unionValues.Add(altName.Value.pwszDNSName);
break;
case CertAltNameChoice.CERT_ALT_NAME_URL:
altName.Value = new CERT_ALT_NAME_ENTRY_UNION
{
pwszURL = Marshal.StringToHGlobalUni((string)altNames[index].Value)
};
unionValues.Add(altName.Value.pwszURL);
break;
case CertAltNameChoice.CERT_ALT_NAME_IP_ADDRESS:
var ip = (IPAddress)altNames[index].Value;
var addressBytes = ip.GetAddressBytes();
var ipBytes = Marshal.AllocHGlobal(addressBytes.Length);
Marshal.Copy(addressBytes, 0, ipBytes, addressBytes.Length);
altName.Value = new CERT_ALT_NAME_ENTRY_UNION
{
IPAddress = new CRYPTOAPI_BLOB
{
cbData = (uint)addressBytes.Length,
pbData = ipBytes
}
};
unionValues.Add(ipBytes);
break;
}
Marshal.StructureToPtr(altName, IntPtrArithmetic.Add(altNamesBuffer, offset), false);
}
certAltName.rgAltEntry = altNamesBuffer;
uint dataSize = 0;
LocalBufferSafeHandle data;
if (!Crypt32.CryptEncodeObjectEx(EncodingType.X509_ASN_ENCODING, OIDs.szOID_SUBJECT_ALT_NAME2, ref certAltName, 0x8000, IntPtr.Zero, out data, ref dataSize))
{
throw new Win32Exception(Marshal.GetLastWin32Error());
}
using (data)
{
var buffer = new byte[dataSize];
Marshal.Copy(data.DangerousGetHandle(), buffer, 0, (int)dataSize);
return(buffer);
}
}
finally
{
Marshal.FreeHGlobal(altNamesBuffer);
unionValues.ForEach(Marshal.FreeHGlobal);
}
}