public DesktopSecurity(Desktop desktop, AccessControlSections includeSections)
: base(false /* isContainer */, ResourceType.WindowObject, desktop, includeSections)
{
this.desktop = desktop;
}
/// <summary>
/// Creates a new desktop with minimal rights.
/// </summary>
/// <param name="tracer">A tracer instance.</param>
/// <returns>The desktop instance.</returns>
public static Desktop Create(ITracer tracer, string mandatoryLevelSacl)
{
using (var disposalEscrow = new DisposalEscrow())
using (Desktop currentDesktop = Desktop.GetCurrent())
{
try
{
string name = "sbox" + DateTime.UtcNow.Ticks;
tracer.Trace(nameof(Desktop), "Creating desktop '{0}'", name);
SECURITY_ATTRIBUTES securityAttributes = null;
if (mandatoryLevelSacl != null)
{
tracer.Trace(nameof(Desktop), "Generating security attributes for '{0}'", mandatoryLevelSacl);
// If a security descriptor (in SDDL form) was provided convert it to binary form and then marshal
// it into native memory to that we can pass it in to the native method.
var rawSecurityDescriptor = new RawSecurityDescriptor(mandatoryLevelSacl);
var binaryForm = new byte[rawSecurityDescriptor.BinaryLength];
rawSecurityDescriptor.GetBinaryForm(binaryForm, 0 /* offset */);
var nativeBinaryForm = disposalEscrow.Add(new SafeHGlobalBuffer(binaryForm.Length));
Marshal.Copy(binaryForm, 0 /* startIndex */, nativeBinaryForm.DangerousGetHandle(), binaryForm.Length);
securityAttributes = new SECURITY_ATTRIBUTES {
lpSecurityDescriptor = nativeBinaryForm.DangerousGetHandle()
};
}
// Since we're creating the desktop we'll ask for all rights so that we have the ability to modify security as
// required. Since the created desktop will be referenced by name when creating the process this will not impact
// the security of the desktop.
IntPtr unsafeDesktopHandle = Methods.CreateDesktop(
name,
device: null,
deviceMode: null,
flags: 0,
accessMask: DESKTOP_RIGHTS.GENERIC_ALL,
attributes: securityAttributes);
if (unsafeDesktopHandle == IntPtr.Zero)
{
throw
new SandboxException(
$"Unable to create new desktop",
new Win32Exception());
}
tracer.Trace(nameof(Desktop), "Desktop successfully created");
return(new Desktop(unsafeDesktopHandle, ownsHandle: true)
{
Name = name,
});
}
finally
{
// Since CreateDesktop automatically switches to the new desktop we need to make sure that we switch back
// to the original one.
currentDesktop.MakeCurrent();
}
}
}
