1 files changed, 474 insertions, 0 deletions
diff --git a/ipc/winpipe/winpipe.go b/ipc/winpipe/winpipe.go
new file mode 100644
index 0000000..f02f3d8
--- /dev/null
+++ b/ipc/winpipe/winpipe.go
@@ -0,0 +1,474 @@
+// +build windows
+
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2005 Microsoft
+ * Copyright (C) 2017-2021 WireGuard LLC. All Rights Reserved.
+ */
+
+// Package winpipe implements a net.Conn and net.Listener around Windows named pipes.
+package winpipe
+
+import (
+	"context"
+	"io"
+	"net"
+	"os"
+	"runtime"
+	"time"
+	"unsafe"
+
+	"golang.org/x/sys/windows"
+)
+
+type pipe struct {
+	*file
+	path string
+}
+
+type messageBytePipe struct {
+	pipe
+	writeClosed bool
+	readEOF     bool
+}
+
+type pipeAddress string
+
+func (f *pipe) LocalAddr() net.Addr {
+	return pipeAddress(f.path)
+}
+
+func (f *pipe) RemoteAddr() net.Addr {
+	return pipeAddress(f.path)
+}
+
+func (f *pipe) SetDeadline(t time.Time) error {
+	f.SetReadDeadline(t)
+	f.SetWriteDeadline(t)
+	return nil
+}
+
+// CloseWrite closes the write side of a message pipe in byte mode.
+func (f *messageBytePipe) CloseWrite() error {
+	if f.writeClosed {
+		return io.ErrClosedPipe
+	}
+	err := f.file.Flush()
+	if err != nil {
+		return err
+	}
+	_, err = f.file.Write(nil)
+	if err != nil {
+		return err
+	}
+	f.writeClosed = true
+	return nil
+}
+
+// Write writes bytes to a message pipe in byte mode. Zero-byte writes are ignored, since
+// they are used to implement CloseWrite.
+func (f *messageBytePipe) Write(b []byte) (int, error) {
+	if f.writeClosed {
+		return 0, io.ErrClosedPipe
+	}
+	if len(b) == 0 {
+		return 0, nil
+	}
+	return f.file.Write(b)
+}
+
+// Read reads bytes from a message pipe in byte mode. A read of a zero-byte message on a message
+// mode pipe will return io.EOF, as will all subsequent reads.
+func (f *messageBytePipe) Read(b []byte) (int, error) {
+	if f.readEOF {
+		return 0, io.EOF
+	}
+	n, err := f.file.Read(b)
+	if err == io.EOF {
+		// If this was the result of a zero-byte read, then
+		// it is possible that the read was due to a zero-size
+		// message. Since we are simulating CloseWrite with a
+		// zero-byte message, ensure that all future Read calls
+		// also return EOF.
+		f.readEOF = true
+	} else if err == windows.ERROR_MORE_DATA {
+		// ERROR_MORE_DATA indicates that the pipe's read mode is message mode
+		// and the message still has more bytes. Treat this as a success, since
+		// this package presents all named pipes as byte streams.
+		err = nil
+	}
+	return n, err
+}
+
+func (f *pipe) Handle() windows.Handle {
+	return f.handle
+}
+
+func (s pipeAddress) Network() string {
+	return "pipe"
+}
+
+func (s pipeAddress) String() string {
+	return string(s)
+}
+
+// tryDialPipe attempts to dial the specified pipe until cancellation or timeout.
+func tryDialPipe(ctx context.Context, path *string) (windows.Handle, error) {
+	for {
+		select {
+		case <-ctx.Done():
+			return 0, ctx.Err()
+		default:
+			path16, err := windows.UTF16PtrFromString(*path)
+			if err != nil {
+				return 0, err
+			}
+			h, err := windows.CreateFile(path16, windows.GENERIC_READ|windows.GENERIC_WRITE, 0, nil, windows.OPEN_EXISTING, windows.FILE_FLAG_OVERLAPPED|windows.SECURITY_SQOS_PRESENT|windows.SECURITY_ANONYMOUS, 0)
+			if err == nil {
+				return h, nil
+			}
+			if err != windows.ERROR_PIPE_BUSY {
+				return h, &os.PathError{Err: err, Op: "open", Path: *path}
+			}
+			// Wait 10 msec and try again. This is a rather simplistic
+			// view, as we always try each 10 milliseconds.
+			time.Sleep(10 * time.Millisecond)
+		}
+	}
+}
+
+// DialConfig exposes various options for use in Dial and DialContext.
+type DialConfig struct {
+	ExpectedOwner *windows.SID // If non-nil, the pipe is verified to be owned by this SID.
+}
+
+// Dial connects to the specified named pipe by path, timing out if the connection
+// takes longer than the specified duration. If timeout is nil, then we use
+// a default timeout of 2 seconds.
+func Dial(path string, timeout *time.Duration, config *DialConfig) (net.Conn, error) {
+	var absTimeout time.Time
+	if timeout != nil {
+		absTimeout = time.Now().Add(*timeout)
+	} else {
+		absTimeout = time.Now().Add(2 * time.Second)
+	}
+	ctx, _ := context.WithDeadline(context.Background(), absTimeout)
+	conn, err := DialContext(ctx, path, config)
+	if err == context.DeadlineExceeded {
+		return nil, os.ErrDeadlineExceeded
+	}
+	return conn, err
+}
+
+// DialContext attempts to connect to the specified named pipe by path
+// cancellation or timeout.
+func DialContext(ctx context.Context, path string, config *DialConfig) (net.Conn, error) {
+	if config == nil {
+		config = &DialConfig{}
+	}
+	var err error
+	var h windows.Handle
+	h, err = tryDialPipe(ctx, &path)
+	if err != nil {
+		return nil, err
+	}
+
+	if config.ExpectedOwner != nil {
+		sd, err := windows.GetSecurityInfo(h, windows.SE_FILE_OBJECT, windows.OWNER_SECURITY_INFORMATION)
+		if err != nil {
+			windows.Close(h)
+			return nil, err
+		}
+		realOwner, _, err := sd.Owner()
+		if err != nil {
+			windows.Close(h)
+			return nil, err
+		}
+		if !realOwner.Equals(config.ExpectedOwner) {
+			windows.Close(h)
+			return nil, windows.ERROR_ACCESS_DENIED
+		}
+	}
+
+	var flags uint32
+	err = windows.GetNamedPipeInfo(h, &flags, nil, nil, nil)
+	if err != nil {
+		windows.Close(h)
+		return nil, err
+	}
+
+	f, err := makeFile(h)
+	if err != nil {
+		windows.Close(h)
+		return nil, err
+	}
+
+	// If the pipe is in message mode, return a message byte pipe, which
+	// supports CloseWrite.
+	if flags&windows.PIPE_TYPE_MESSAGE != 0 {
+		return &messageBytePipe{
+			pipe: pipe{file: f, path: path},
+		}, nil
+	}
+	return &pipe{file: f, path: path}, nil
+}
+
+type acceptResponse struct {
+	f   *file
+	err error
+}
+
+type pipeListener struct {
+	firstHandle windows.Handle
+	path        string
+	config      ListenConfig
+	acceptCh    chan (chan acceptResponse)
+	closeCh     chan int
+	doneCh      chan int
+}
+
+func makeServerPipeHandle(path string, sd *windows.SECURITY_DESCRIPTOR, c *ListenConfig, first bool) (windows.Handle, error) {
+	path16, err := windows.UTF16PtrFromString(path)
+	if err != nil {
+		return 0, &os.PathError{Op: "open", Path: path, Err: err}
+	}
+
+	var oa windows.OBJECT_ATTRIBUTES
+	oa.Length = uint32(unsafe.Sizeof(oa))
+
+	var ntPath windows.NTUnicodeString
+	if err := windows.RtlDosPathNameToNtPathName(path16, &ntPath, nil, nil); err != nil {
+		if ntstatus, ok := err.(windows.NTStatus); ok {
+			err = ntstatus.Errno()
+		}
+		return 0, &os.PathError{Op: "open", Path: path, Err: err}
+	}
+	defer windows.LocalFree(windows.Handle(unsafe.Pointer(ntPath.Buffer)))
+	oa.ObjectName = &ntPath
+
+	// The security descriptor is only needed for the first pipe.
+	if first {
+		if sd != nil {
+			oa.SecurityDescriptor = sd
+		} else {
+			// Construct the default named pipe security descriptor.
+			var acl *windows.ACL
+			if err := windows.RtlDefaultNpAcl(&acl); err != nil {
+				return 0, err
+			}
+			defer windows.LocalFree(windows.Handle(unsafe.Pointer(acl)))
+			sd, err := windows.NewSecurityDescriptor()
+			if err != nil {
+				return 0, err
+			}
+			if err = sd.SetDACL(acl, true, false); err != nil {
+				return 0, err
+			}
+			oa.SecurityDescriptor = sd
+		}
+	}
+
+	typ := uint32(windows.FILE_PIPE_REJECT_REMOTE_CLIENTS)
+	if c.MessageMode {
+		typ |= windows.FILE_PIPE_MESSAGE_TYPE
+	}
+
+	disposition := uint32(windows.FILE_OPEN)
+	access := uint32(windows.GENERIC_READ | windows.GENERIC_WRITE | windows.SYNCHRONIZE)
+	if first {
+		disposition = windows.FILE_CREATE
+		// By not asking for read or write access, the named pipe file system
+		// will put this pipe into an initially disconnected state, blocking
+		// client connections until the next call with first == false.
+		access = windows.SYNCHRONIZE
+	}
+
+	timeout := int64(-50 * 10000) // 50ms
+
+	var (
+		h    windows.Handle
+		iosb windows.IO_STATUS_BLOCK
+	)
+	err = windows.NtCreateNamedPipeFile(&h, access, &oa, &iosb, windows.FILE_SHARE_READ|windows.FILE_SHARE_WRITE, disposition, 0, typ, 0, 0, 0xffffffff, uint32(c.InputBufferSize), uint32(c.OutputBufferSize), &timeout)
+	if err != nil {
+		if ntstatus, ok := err.(windows.NTStatus); ok {
+			err = ntstatus.Errno()
+		}
+		return 0, &os.PathError{Op: "open", Path: path, Err: err}
+	}
+
+	runtime.KeepAlive(ntPath)
+	return h, nil
+}
+
+func (l *pipeListener) makeServerPipe() (*file, error) {
+	h, err := makeServerPipeHandle(l.path, nil, &l.config, false)
+	if err != nil {
+		return nil, err
+	}
+	f, err := makeFile(h)
+	if err != nil {
+		windows.Close(h)
+		return nil, err
+	}
+	return f, nil
+}
+
+func (l *pipeListener) makeConnectedServerPipe() (*file, error) {
+	p, err := l.makeServerPipe()
+	if err != nil {
+		return nil, err
+	}
+
+	// Wait for the client to connect.
+	ch := make(chan error)
+	go func(p *file) {
+		ch <- connectPipe(p)
+	}(p)
+
+	select {
+	case err = <-ch:
+		if err != nil {
+			p.Close()
+			p = nil
+		}
+	case <-l.closeCh:
+		// Abort the connect request by closing the handle.
+		p.Close()
+		p = nil
+		err = <-ch
+		if err == nil || err == os.ErrClosed {
+			err = net.ErrClosed
+		}
+	}
+	return p, err
+}
+
+func (l *pipeListener) listenerRoutine() {
+	closed := false
+	for !closed {
+		select {
+		case <-l.closeCh:
+			closed = true
+		case responseCh := <-l.acceptCh:
+			var (
+				p   *file
+				err error
+			)
+			for {
+				p, err = l.makeConnectedServerPipe()
+				// If the connection was immediately closed by the client, try
+				// again.
+				if err != windows.ERROR_NO_DATA {
+					break
+				}
+			}
+			responseCh <- acceptResponse{p, err}
+			closed = err == net.ErrClosed
+		}
+	}
+	windows.Close(l.firstHandle)
+	l.firstHandle = 0
+	// Notify Close and Accept callers that the handle has been closed.
+	close(l.doneCh)
+}
+
+// ListenConfig contains configuration for the pipe listener.
+type ListenConfig struct {
+	// SecurityDescriptor contains a Windows security descriptor. If nil, the default from RtlDefaultNpAcl is used.
+	SecurityDescriptor *windows.SECURITY_DESCRIPTOR
+
+	// MessageMode determines whether the pipe is in byte or message mode. In either
+	// case the pipe is read in byte mode by default. The only practical difference in
+	// this implementation is that CloseWrite is only supported for message mode pipes;
+	// CloseWrite is implemented as a zero-byte write, but zero-byte writes are only
+	// transferred to the reader (and returned as io.EOF in this implementation)
+	// when the pipe is in message mode.
+	MessageMode bool
+
+	// InputBufferSize specifies the initial size of the input buffer, in bytes, which the OS will grow as needed.
+	InputBufferSize int32
+
+	// OutputBufferSize specifies the initial size of the output buffer, in bytes, which the OS will grow as needed.
+	OutputBufferSize int32
+}
+
+// Listen creates a listener on a Windows named pipe path,such as \\.\pipe\mypipe.
+// The pipe must not already exist.
+func Listen(path string, c *ListenConfig) (net.Listener, error) {
+	if c == nil {
+		c = &ListenConfig{}
+	}
+	h, err := makeServerPipeHandle(path, c.SecurityDescriptor, c, true)
+	if err != nil {
+		return nil, err
+	}
+	l := &pipeListener{
+		firstHandle: h,
+		path:        path,
+		config:      *c,
+		acceptCh:    make(chan (chan acceptResponse)),
+		closeCh:     make(chan int),
+		doneCh:      make(chan int),
+	}
+	// The first connection is swallowed on Windows 7 & 8, so synthesize it.
+	if maj, _, _ := windows.RtlGetNtVersionNumbers(); maj <= 8 {
+		path16, err := windows.UTF16PtrFromString(path)
+		if err == nil {
+			h, err = windows.CreateFile(path16, 0, 0, nil, windows.OPEN_EXISTING, windows.SECURITY_SQOS_PRESENT|windows.SECURITY_ANONYMOUS, 0)
+			if err == nil {
+				windows.CloseHandle(h)
+			}
+		}
+	}
+	go l.listenerRoutine()
+	return l, nil
+}
+
+func connectPipe(p *file) error {
+	c, err := p.prepareIo()
+	if err != nil {
+		return err
+	}
+	defer p.wg.Done()
+
+	err = windows.ConnectNamedPipe(p.handle, &c.o)
+	_, err = p.asyncIo(c, nil, 0, err)
+	if err != nil && err != windows.ERROR_PIPE_CONNECTED {
+		return err
+	}
+	return nil
+}
+
+func (l *pipeListener) Accept() (net.Conn, error) {
+	ch := make(chan acceptResponse)
+	select {
+	case l.acceptCh <- ch:
+		response := <-ch
+		err := response.err
+		if err != nil {
+			return nil, err
+		}
+		if l.config.MessageMode {
+			return &messageBytePipe{
+				pipe: pipe{file: response.f, path: l.path},
+			}, nil
+		}
+		return &pipe{file: response.f, path: l.path}, nil
+	case <-l.doneCh:
+		return nil, net.ErrClosed
+	}
+}
+
+func (l *pipeListener) Close() error {
+	select {
+	case l.closeCh <- 1:
+		<-l.doneCh
+	case <-l.doneCh:
+	}
+	return nil
+}
+
+func (l *pipeListener) Addr() net.Addr {
+	return pipeAddress(l.path)
+}