From 82f3e9e2afc1b52a88a691b1ce173623e525e4f0 Mon Sep 17 00:00:00 2001 From: "Jason A. Donenfeld" Date: Wed, 3 Mar 2021 12:26:59 +0100 Subject: winpipe: move syscalls into x/sys Signed-off-by: Jason A. Donenfeld --- ipc/winpipe/winpipe.go | 474 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 474 insertions(+) create mode 100644 ipc/winpipe/winpipe.go (limited to 'ipc/winpipe/winpipe.go') 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) +} -- cgit v1.2.3