private static Credential ReadCredential(PrivateCredential credential)
{
var applicationName = Marshal.PtrToStringUni(credential.TargetName);
var userName = Marshal.PtrToStringUni(credential.UserName);
string insecureSecret = null;
if (credential.CredentialBlob != IntPtr.Zero)
{
insecureSecret = Marshal.PtrToStringUni(credential.CredentialBlob, (int)credential.CredentialBlobSize / 2);
}
var secret = SecureStringHelper.GetSecureString(insecureSecret);
return(new Credential(credential.Type, applicationName, userName, secret));
}
/// <summary>
/// Save user credentials for current application
/// </summary>
/// <param name="userName">User name</param>
/// <param name="secret">User secret</param>
/// <param name="credentialPersistence">Persistence type</param>
/// <returns>Zero in case of success</returns>
public int WriteCredential(string userName, string secret, CredentialPersistence credentialPersistence = CredentialPersistence.LocalMachine)
{
var byteArray = Encoding.Unicode.GetBytes(secret);
if (byteArray.Length > 512)
{
throw new ArgumentOutOfRangeException(nameof(secret), @"The secret message has exceeded 512 bytes.");
}
var credential = new PrivateCredential
{
AttributeCount = 0,
Attributes = IntPtr.Zero,
Comment = IntPtr.Zero,
TargetAlias = IntPtr.Zero,
Type = CredentialType.Generic,
Persist = (uint)credentialPersistence,
CredentialBlobSize = (uint)Encoding.Unicode.GetBytes(secret).Length,
TargetName = Marshal.StringToCoTaskMemUni(_applicationName),
CredentialBlob = Marshal.StringToCoTaskMemUni(secret),
UserName = Marshal.StringToCoTaskMemUni(userName ?? Environment.UserName)
};
var written = CredWrite(ref credential, 0);
var lastError = Marshal.GetLastWin32Error();
Marshal.FreeCoTaskMem(credential.TargetName);
Marshal.FreeCoTaskMem(credential.CredentialBlob);
Marshal.FreeCoTaskMem(credential.UserName);
if (written)
{
return(0);
}
throw new Exception($"CredWrite failed with the error code {lastError}.");
}
private static extern bool CredWrite([In] ref PrivateCredential userCredential, [In] uint flags);
