add SDDL support

example_windows_test.go

@@ -26,7 +26,7 @@ func ExampleDial() {
 
 // Use Listen to start a server, and accept connections with Accept().
 func ExampleListen() {
-	ln, err := npipe.Listen(`\\.\pipe\mypipe`)
+	ln, err := npipe.Listen(`\\.\pipe\mypipe`, npipe.AllowEveryone)
 	if err != nil {
 		// handle error
 	}

npipe_windows.go

@@ -253,8 +253,12 @@ func dial(address string, timeout uint32) (*PipeConn, error) {
 // The address must be of the form \\.\pipe\<name>
 //
 // Listen will return a PipeError for an incorrectly formatted pipe name.
-func Listen(address string) (*PipeListener, error) {
-	handle, err := createPipe(address, true)
+func Listen(address string, SDDL ...string) (*PipeListener, error) {
+	var sddl string
+	if len(SDDL) > 0 {
+		sddl = SDDL[0]
+	}
+	handle, err := createPipe(address, true, sddl)
 	if err == error_invalid_name {
 		return nil, badAddr(address)
 	}
@@ -295,7 +299,7 @@ func (l *PipeListener) AcceptPipe() (*PipeConn, error) {
 	handle := l.handle
 	if handle == 0 {
 		var err error
-		handle, err = createPipe(string(l.addr), false)
+		handle, err = createPipe(string(l.addr), false, ``)
 		if err != nil {
 			return nil, err
 		}
@@ -463,7 +467,7 @@ func (a PipeAddr) String() string {
 // with the same arguments, since subsequent calls to create pipe need
 // to use the same arguments as the first one. If first is set, fail
 // if the pipe already exists.
-func createPipe(address string, first bool) (syscall.Handle, error) {
+func createPipe(address string, first bool, SDDL string) (syscall.Handle, error) {
 	n, err := syscall.UTF16PtrFromString(address)
 	if err != nil {
 		return 0, err
@@ -473,10 +477,13 @@ func createPipe(address string, first bool) (syscall.Handle, error) {
 		mode |= file_flag_first_pipe_instance
 	}
 
-	sa, err := initSecurityAttributes()
+	sa, err := initSecurityAttributes(SDDL)
 	if err != nil {
 		return 0, err
 	}
+	if 0 != sa.SecurityDescriptor {
+		defer syscall.LocalFree((syscall.Handle)(sa.SecurityDescriptor))
+	}
 
 	return createNamedPipe(n,
 		mode,

sec_attr.go

@@ -1,46 +1,35 @@
 package npipe
 
 import (
-	"os"
 	"syscall"
 	"unsafe"
 )
 
-const SECURITY_DESCRIPTOR_REVISION = 1
+const SDDL_REVISION_1 = 1
+const AllowEveryone = `D:(A;;FA;;;WD)`
+const AllowAnonymous = `D:(A;;FA;;;AN)`
 
 var (
-	advapi32                         = syscall.NewLazyDLL("advapi32.dll")
-	procInitializeSecurityDescriptor = advapi32.NewProc("InitializeSecurityDescriptor")
-	procSetSecurityDescriptorDacl    = advapi32.NewProc("SetSecurityDescriptorDacl")
+	advapi32 = syscall.NewLazyDLL("advapi32.dll")
+	procConvertStringSecurityDescriptorToSecurityDescriptor = advapi32.NewProc(`ConvertStringSecurityDescriptorToSecurityDescriptorW`)
 )
 
-func initSecurityAttributes() (*syscall.SecurityAttributes, error) {
-
-	// create security descriptor
-	sd := make([]byte, 4096)
-	if res, _, err := procInitializeSecurityDescriptor.Call(
-		uintptr(unsafe.Pointer(&sd[0])),
-		SECURITY_DESCRIPTOR_REVISION); int(res) == 0 {
-
-		return nil, os.NewSyscallError("InitializeSecurityDescriptor", err)
-	}
-
-	// configure security descriptor
-	present := 1
-	defaulted := 0
-	if res, _, err := procSetSecurityDescriptorDacl.Call(
-		uintptr(unsafe.Pointer(&sd[0])),
-		uintptr(present),
-		uintptr(unsafe.Pointer(nil)), // acl
-		uintptr(defaulted)); int(res) == 0 {
-
-		return nil, os.NewSyscallError("SetSecurityDescriptorDacl", err)
-	}
-
+func initSecurityAttributes(SDDL string) (*syscall.SecurityAttributes, error) {
 	var sa syscall.SecurityAttributes
 	sa.Length = uint32(unsafe.Sizeof(sa))
-	sa.SecurityDescriptor = uintptr(unsafe.Pointer(&sd[0]))
-
+	if `` != SDDL {
+		u, err := syscall.UTF16PtrFromString(SDDL)
+		if nil != err {
+			return nil, err
+		}
+		r0, _, err := procConvertStringSecurityDescriptorToSecurityDescriptor.Call(
+			uintptr(unsafe.Pointer(u)),
+			SDDL_REVISION_1,
+			uintptr(unsafe.Pointer(&sa.SecurityDescriptor)),
+			uintptr(0))
+		if 0 == r0 {
+			return nil, err
+		}
+	}
 	return &sa, nil
-
 }