public static extern int CredUIPromptForWindowsCredentials(
ref CredentialUiInfo credInfo,
uint authError,
ref uint authPackage,
IntPtr inAuthBuffer,
uint inAuthBufferSize,
out IntPtr outAuthBuffer,
out uint outAuthBufferSize,
ref bool saveCredentials,
CredentialUiWindowsFlags flags);
public static extern int CredUIPromptForWindowsCredentials(ref CredentialUiInfo credInfo, uint authError, ref CredentialPackFlags authPackage, IntPtr inAuthBuffer, uint inAuthBufferSize, out IntPtr outAuthBuffer, out uint outAuthBufferSize, ref bool saveCredentials, CredentialUiWindowsFlags flags);
public static bool DisplayModal(Program program,
ref CredentialUiInfo credUiInfo,
ref CredentialPackFlags authPackage,
IntPtr packedAuthBufferPtr,
uint packedAuthBufferSize,
IntPtr inBufferPtr,
int inBufferSize,
bool saveCredentials,
CredentialUiWindowsFlags flags,
out string username,
out string password)
{
if (program is null)
{
throw new ArgumentNullException(nameof(program));
}
int error;
try
{
// open a standard Windows authentication dialog to acquire username + password credentials
if ((error = CredUIPromptForWindowsCredentials(credInfo: ref credUiInfo,
authError: 0,
authPackage: ref authPackage,
inAuthBuffer: inBufferPtr,
inAuthBufferSize: (uint)inBufferSize,
outAuthBuffer: out packedAuthBufferPtr,
outAuthBufferSize: out packedAuthBufferSize,
saveCredentials: ref saveCredentials,
flags: flags)) != Win32Error.Success)
{
program.Trace.WriteLine($"credential prompt failed ('{Win32Error.GetText(error)}').");
username = null;
password = null;
return(false);
}
// use `StringBuilder` references instead of string so that they can be written to
var usernameBuffer = new StringBuilder(512);
var domainBuffer = new StringBuilder(256);
var passwordBuffer = new StringBuilder(512);
int usernameLen = usernameBuffer.Capacity;
int passwordLen = passwordBuffer.Capacity;
int domainLen = domainBuffer.Capacity;
// unpack the result into locally useful data
if (!CredUnPackAuthenticationBuffer(flags: authPackage,
authBuffer: packedAuthBufferPtr,
authBufferSize: packedAuthBufferSize,
username: usernameBuffer,
maxUsernameLen: ref usernameLen,
domainName: domainBuffer,
maxDomainNameLen: ref domainLen,
password: passwordBuffer,
maxPasswordLen: ref passwordLen))
{
username = null;
password = null;
error = Marshal.GetLastWin32Error();
program.Trace.WriteLine($"failed to unpack buffer ('{Win32Error.GetText(error)}').");
return(false);
}
program.Trace.WriteLine("successfully acquired credentials from user.");
username = usernameBuffer.ToString();
password = passwordBuffer.ToString();
return(true);
}
finally
{
if (packedAuthBufferPtr != IntPtr.Zero)
{
Marshal.FreeHGlobal(packedAuthBufferPtr);
}
}
}
