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);
}
}
private static byte[] EncodeExtension(IList<X509AlternativeName> altNames)
{
var certAltName = new CERT_ALT_NAME_INFO
{
cAltEntry = (uint)altNames.Count
};
var structSize = Marshal.SizeOf<CERT_ALT_NAME_ENTRY>();
var altNamesBuffer = Marshal.AllocHGlobal(structSize * altNames.Count);
var unionValues = new List<IntPtr>();
byte[] data = null;
int dataSize = 0;
try
{
for (int index = 0, offset = 0; index < altNames.Count; index++, offset += structSize)
{
var altName = new CERT_ALT_NAME_ENTRY
{
dwAltNameChoice = (uint)altNames[index].Type
};
switch (altNames[index].Type)
{
case X509AlternateNameType.DnsName:
altName.Value = new CERT_ALT_NAME_ENTRY_UNION
{
pwszDNSName = Marshal.StringToHGlobalUni((string)altNames[index].Value)
};
unionValues.Add(altName.Value.pwszDNSName);
break;
case X509AlternateNameType.Url:
altName.Value = new CERT_ALT_NAME_ENTRY_UNION
{
pwszURL = Marshal.StringToHGlobalUni((string)altNames[index].Value)
};
unionValues.Add(altName.Value.pwszURL);
break;
case X509AlternateNameType.IPAddress:
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, altNamesBuffer + offset, false);
}
certAltName.rgAltEntry = altNamesBuffer;
if (!NativeMethods.CryptEncodeObjectEx(
X509_ASN_ENCODING,
OID_SUBJECT_ALT_NAME2,
ref certAltName,
0,
IntPtr.Zero,
null,
ref dataSize))
{
throw new Win32Exception(Marshal.GetLastWin32Error());
}
data = new byte[dataSize];
if (!NativeMethods.CryptEncodeObjectEx(
X509_ASN_ENCODING,
OID_SUBJECT_ALT_NAME2,
ref certAltName,
0,
IntPtr.Zero,
data,
ref dataSize))
{
throw new Win32Exception(Marshal.GetLastWin32Error());
}
return data;
}
finally
{
Marshal.FreeHGlobal(altNamesBuffer);
unionValues.ForEach(Marshal.FreeHGlobal);
}
}
// see MSDN docs for more info
public CERT_ACCESS_DESCRIPTION(IntPtr buffer, int offset)
{
IntPtr str = Marshal.ReadIntPtr(buffer, offset);
this.pszAccessMethod = Marshal.PtrToStringAnsi(str);
this.AccessLocation = new CERT_ALT_NAME_ENTRY(buffer, offset + IntPtr.Size);
}
// creates the alternate name extension for the certificate.
static void CreateSubjectAltNameExtension(
string applicationUri,
IList<string> hostNames,
ref CERT_EXTENSION pExtension)
{
int count = hostNames.Count + 1;
// initialize extension.
pExtension.pszObjId = szOID_SUBJECT_ALT_NAME2;
pExtension.fCritical = 0;
IntPtr pData = IntPtr.Zero;
int dwDataSize = 0;
// build list of alternate names.
IntPtr pAlternateNames = IntPtr.Zero;
IntPtr pEntries = Marshal.AllocHGlobal(Marshal.SizeOf(typeof(CERT_ALT_NAME_ENTRY))*count);
// create structure to encode.
try
{
// set application uri.
CERT_ALT_NAME_ENTRY pEntry = new CERT_ALT_NAME_ENTRY();
pEntry.dwAltNameChoice = CERT_ALT_NAME_URL;
pEntry.Value.pwszURL = Marshal.StringToHGlobalUni(applicationUri);
Marshal.StructureToPtr(pEntry, pEntries, false);
IntPtr pPos = new IntPtr(pEntries.ToInt64() + Marshal.SizeOf(typeof(CERT_ALT_NAME_ENTRY)));
for (int ii = 0; ii < hostNames.Count; ii++)
{
System.Net.IPAddress ipAddress = null;
// check for ip address.
if (System.Net.IPAddress.TryParse(hostNames[ii], out ipAddress))
{
byte[] bytes = ipAddress.GetAddressBytes();
pEntry.dwAltNameChoice = CERT_ALT_NAME_IP_ADDRESS;
pEntry.Value.IPAddress.cbData = bytes.Length;
pEntry.Value.IPAddress.pbData = AllocBytes(bytes);
}
// treat as DNS host name.
else
{
pEntry.dwAltNameChoice = CERT_ALT_NAME_DNS_NAME;
pEntry.Value.pwszDNSName = Marshal.StringToHGlobalUni(hostNames[ii]);
}
Marshal.StructureToPtr(pEntry, pPos, false);
pPos = new IntPtr(pPos.ToInt64() + Marshal.SizeOf(typeof(CERT_ALT_NAME_ENTRY)));
}
CERT_ALT_NAME_INFO alternateNames = new CERT_ALT_NAME_INFO();
alternateNames.cAltEntry = count;
alternateNames.rgAltEntry = pEntries;
pAlternateNames = Marshal.AllocHGlobal(Marshal.SizeOf(typeof(CERT_ALT_NAME_INFO)));
Marshal.StructureToPtr(alternateNames, pAlternateNames, false);
// calculate amount of memory required.
int bResult = NativeMethods.CryptEncodeObjectEx(
X509_ASN_ENCODING | PKCS_7_ASN_ENCODING,
szOID_SUBJECT_ALT_NAME2, // X509_ALTERNATE_NAME,
pAlternateNames,
0,
IntPtr.Zero,
IntPtr.Zero,
ref dwDataSize);
if (bResult == 0)
{
throw new InvalidOperationException("Could not get size for subject alternate name extension.");
}
// allocate memory.
pData = Marshal.AllocHGlobal(dwDataSize);
// encode blob.
bResult = NativeMethods.CryptEncodeObjectEx(
X509_ASN_ENCODING | PKCS_7_ASN_ENCODING,
szOID_SUBJECT_ALT_NAME2, // X509_ALTERNATE_NAME,
pAlternateNames,
0,
IntPtr.Zero,
pData,
ref dwDataSize);
if (bResult == 0)
{
throw new InvalidOperationException("Could not create subject alternate name extension.");
}
pExtension.Value.cbData = dwDataSize;
pExtension.Value.pbData = pData;
pData = IntPtr.Zero;
}
finally
{
if (pData != IntPtr.Zero)
{
Marshal.FreeHGlobal(pData);
}
if (pAlternateNames != IntPtr.Zero)
{
Marshal.DestroyStructure(pAlternateNames, typeof(CERT_ALT_NAME_INFO));
Marshal.FreeHGlobal(pAlternateNames);
}
if (pEntries != IntPtr.Zero)
{
IntPtr pPos = pEntries;
for (int ii = 0; ii < count; ii++)
{
CERT_ALT_NAME_ENTRY pEntry = (CERT_ALT_NAME_ENTRY)Marshal.PtrToStructure(pPos, typeof(CERT_ALT_NAME_ENTRY));
pPos = new IntPtr(pPos.ToInt64() + Marshal.SizeOf(typeof(CERT_ALT_NAME_ENTRY)));
switch (pEntry.dwAltNameChoice)
{
case CERT_ALT_NAME_URL:
{
Marshal.FreeHGlobal(pEntry.Value.pwszURL);
break;
}
case CERT_ALT_NAME_DNS_NAME:
{
Marshal.FreeHGlobal(pEntry.Value.pwszDNSName);
break;
}
case CERT_ALT_NAME_IP_ADDRESS:
{
Marshal.FreeHGlobal(pEntry.Value.IPAddress.pbData);
break;
}
}
}
Marshal.FreeHGlobal(pEntries);
}
}
}
private static byte[] EncodeExtension(IList <X509AlternativeName> altNames)
{
var certAltName = new CERT_ALT_NAME_INFO
{
cAltEntry = (uint)altNames.Count
};
var structSize = Marshal.SizeOf <CERT_ALT_NAME_ENTRY>();
var altNamesBuffer = Marshal.AllocHGlobal(structSize * altNames.Count);
var unionValues = new List <IntPtr>();
byte[] data = null;
int dataSize = 0;
try
{
for (int index = 0, offset = 0; index < altNames.Count; index++, offset += structSize)
{
var altName = new CERT_ALT_NAME_ENTRY
{
dwAltNameChoice = (uint)altNames[index].Type
};
switch (altNames[index].Type)
{
case X509AlternateNameType.DnsName:
altName.Value = new CERT_ALT_NAME_ENTRY_UNION
{
pwszDNSName = Marshal.StringToHGlobalUni((string)altNames[index].Value)
};
unionValues.Add(altName.Value.pwszDNSName);
break;
case X509AlternateNameType.Url:
altName.Value = new CERT_ALT_NAME_ENTRY_UNION
{
pwszURL = Marshal.StringToHGlobalUni((string)altNames[index].Value)
};
unionValues.Add(altName.Value.pwszURL);
break;
case X509AlternateNameType.IPAddress:
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, altNamesBuffer + offset, false);
}
certAltName.rgAltEntry = altNamesBuffer;
if (!NativeMethods.CryptEncodeObjectEx(
X509_ASN_ENCODING,
OID_SUBJECT_ALT_NAME2,
ref certAltName,
0,
IntPtr.Zero,
null,
ref dataSize))
{
throw new Win32Exception(Marshal.GetLastWin32Error());
}
data = new byte[dataSize];
if (!NativeMethods.CryptEncodeObjectEx(
X509_ASN_ENCODING,
OID_SUBJECT_ALT_NAME2,
ref certAltName,
0,
IntPtr.Zero,
data,
ref dataSize))
{
throw new Win32Exception(Marshal.GetLastWin32Error());
}
return(data);
}
finally
{
Marshal.FreeHGlobal(altNamesBuffer);
unionValues.ForEach(Marshal.FreeHGlobal);
}
}