windows: add support for creating well known SIDs

The security API is already quite extensive, but for some strange
reason, this essential and useful function was left out of the initial
port. So, we add it here, along with the relevant constants and a test
case.

Change-Id: I99568703565addf15603480f11b0edafdfc1718f
Reviewed-on: https://go-review.googlesource.com/c/sys/+/167378
Reviewed-by: Alex Brainman <alex.brainman@gmail.com>
Run-TryBot: Alex Brainman <alex.brainman@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

windows/zsyscall_windows.go

@@ -246,6 +246,7 @@ var (
 	procGetLengthSid                       = modadvapi32.NewProc("GetLengthSid")
 	procCopySid                            = modadvapi32.NewProc("CopySid")
 	procAllocateAndInitializeSid           = modadvapi32.NewProc("AllocateAndInitializeSid")
+	procCreateWellKnownSid                 = modadvapi32.NewProc("CreateWellKnownSid")
 	procFreeSid                            = modadvapi32.NewProc("FreeSid")
 	procEqualSid                           = modadvapi32.NewProc("EqualSid")
 	procCheckTokenMembership               = modadvapi32.NewProc("CheckTokenMembership")
@@ -2654,6 +2655,18 @@ func AllocateAndInitializeSid(identAuth *SidIdentifierAuthority, subAuth byte, s
 	return
 }
 
+func createWellKnownSid(sidType WELL_KNOWN_SID_TYPE, domainSid *SID, sid *SID, sizeSid *uint32) (err error) {
+	r1, _, e1 := syscall.Syscall6(procCreateWellKnownSid.Addr(), 4, uintptr(sidType), uintptr(unsafe.Pointer(domainSid)), uintptr(unsafe.Pointer(sid)), uintptr(unsafe.Pointer(sizeSid)), 0, 0)
+	if r1 == 0 {
+		if e1 != 0 {
+			err = errnoErr(e1)
+		} else {
+			err = syscall.EINVAL
+		}
+	}
+	return
+}
+
 func FreeSid(sid *SID) (err error) {
 	r1, _, e1 := syscall.Syscall(procFreeSid.Addr(), 1, uintptr(unsafe.Pointer(sid)), 0, 0)
 	if r1 != 0 {