wireguard-go/ipc/winpipe/pipe.go

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// +build windows
/* SPDX-License-Identifier: MIT
*
* Copyright (C) 2005 Microsoft
* Copyright (C) 2017-2019 WireGuard LLC. All Rights Reserved.
*/
package winpipe
import (
"context"
"errors"
"fmt"
"io"
"net"
"os"
"runtime"
"time"
"unsafe"
"golang.org/x/sys/windows"
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)
//sys connectNamedPipe(pipe windows.Handle, o *windows.Overlapped) (err error) = ConnectNamedPipe
//sys createNamedPipe(name string, flags uint32, pipeMode uint32, maxInstances uint32, outSize uint32, inSize uint32, defaultTimeout uint32, sa *windows.SecurityAttributes) (handle windows.Handle, err error) [failretval==windows.InvalidHandle] = CreateNamedPipeW
//sys createFile(name string, access uint32, mode uint32, sa *windows.SecurityAttributes, createmode uint32, attrs uint32, templatefile windows.Handle) (handle windows.Handle, err error) [failretval==windows.InvalidHandle] = CreateFileW
//sys getNamedPipeInfo(pipe windows.Handle, flags *uint32, outSize *uint32, inSize *uint32, maxInstances *uint32) (err error) = GetNamedPipeInfo
//sys getNamedPipeHandleState(pipe windows.Handle, state *uint32, curInstances *uint32, maxCollectionCount *uint32, collectDataTimeout *uint32, userName *uint16, maxUserNameSize uint32) (err error) = GetNamedPipeHandleStateW
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//sys localAlloc(uFlags uint32, length uint32) (ptr uintptr) = LocalAlloc
//sys ntCreateNamedPipeFile(pipe *windows.Handle, access uint32, oa *objectAttributes, iosb *ioStatusBlock, share uint32, disposition uint32, options uint32, typ uint32, readMode uint32, completionMode uint32, maxInstances uint32, inboundQuota uint32, outputQuota uint32, timeout *int64) (status ntstatus) = ntdll.NtCreateNamedPipeFile
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//sys rtlNtStatusToDosError(status ntstatus) (winerr error) = ntdll.RtlNtStatusToDosErrorNoTeb
//sys rtlDosPathNameToNtPathName(name *uint16, ntName *unicodeString, filePart uintptr, reserved uintptr) (status ntstatus) = ntdll.RtlDosPathNameToNtPathName_U
//sys rtlDefaultNpAcl(dacl *uintptr) (status ntstatus) = ntdll.RtlDefaultNpAcl
type ioStatusBlock struct {
Status, Information uintptr
}
type objectAttributes struct {
Length uintptr
RootDirectory uintptr
ObjectName *unicodeString
Attributes uintptr
SecurityDescriptor *windows.SECURITY_DESCRIPTOR
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SecurityQoS uintptr
}
type unicodeString struct {
Length uint16
MaximumLength uint16
Buffer uintptr
}
type ntstatus int32
func (status ntstatus) Err() error {
if status >= 0 {
return nil
}
return rtlNtStatusToDosError(status)
}
const (
cSECURITY_SQOS_PRESENT = 0x100000
cSECURITY_ANONYMOUS = 0
cPIPE_TYPE_MESSAGE = 4
cPIPE_READMODE_MESSAGE = 2
cFILE_OPEN = 1
cFILE_CREATE = 2
cFILE_PIPE_MESSAGE_TYPE = 1
cFILE_PIPE_REJECT_REMOTE_CLIENTS = 2
)
var (
// ErrPipeListenerClosed is returned for pipe operations on listeners that have been closed.
// This error should match net.errClosing since docker takes a dependency on its text.
ErrPipeListenerClosed = errors.New("use of closed network connection")
errPipeWriteClosed = errors.New("pipe has been closed for write")
)
type win32Pipe struct {
*win32File
path string
}
type win32MessageBytePipe struct {
win32Pipe
writeClosed bool
readEOF bool
}
type pipeAddress string
func (f *win32Pipe) LocalAddr() net.Addr {
return pipeAddress(f.path)
}
func (f *win32Pipe) RemoteAddr() net.Addr {
return pipeAddress(f.path)
}
func (f *win32Pipe) 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 *win32MessageBytePipe) CloseWrite() error {
if f.writeClosed {
return errPipeWriteClosed
}
err := f.win32File.Flush()
if err != nil {
return err
}
_, err = f.win32File.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 *win32MessageBytePipe) Write(b []byte) (int, error) {
if f.writeClosed {
return 0, errPipeWriteClosed
}
if len(b) == 0 {
return 0, nil
}
return f.win32File.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 *win32MessageBytePipe) Read(b []byte) (int, error) {
if f.readEOF {
return 0, io.EOF
}
n, err := f.win32File.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 {
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// 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 (s pipeAddress) Network() string {
return "pipe"
}
func (s pipeAddress) String() string {
return string(s)
}
// tryDialPipe attempts to dial the pipe at `path` until `ctx` cancellation or timeout.
func tryDialPipe(ctx context.Context, path *string) (windows.Handle, error) {
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for {
select {
case <-ctx.Done():
return windows.Handle(0), ctx.Err()
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default:
h, err := createFile(*path, windows.GENERIC_READ|windows.GENERIC_WRITE, 0, nil, windows.OPEN_EXISTING, windows.FILE_FLAG_OVERLAPPED|cSECURITY_SQOS_PRESENT|cSECURITY_ANONYMOUS, 0)
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if err == nil {
return h, nil
}
if err != windows.ERROR_PIPE_BUSY {
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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(time.Millisecond * 10)
}
}
}
// DialPipe connects to a 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. (We do not use WaitNamedPipe.)
func DialPipe(path string, timeout *time.Duration, expectedOwner *windows.SID) (net.Conn, error) {
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var absTimeout time.Time
if timeout != nil {
absTimeout = time.Now().Add(*timeout)
} else {
absTimeout = time.Now().Add(time.Second * 2)
}
ctx, _ := context.WithDeadline(context.Background(), absTimeout)
conn, err := DialPipeContext(ctx, path, expectedOwner)
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if err == context.DeadlineExceeded {
return nil, ErrTimeout
}
return conn, err
}
// DialPipeContext attempts to connect to a named pipe by `path` until `ctx`
// cancellation or timeout.
func DialPipeContext(ctx context.Context, path string, expectedOwner *windows.SID) (net.Conn, error) {
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var err error
var h windows.Handle
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h, err = tryDialPipe(ctx, &path)
if err != nil {
return nil, err
}
if 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(expectedOwner) {
windows.Close(h)
return nil, windows.ERROR_ACCESS_DENIED
}
}
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var flags uint32
err = getNamedPipeInfo(h, &flags, nil, nil, nil)
if err != nil {
windows.Close(h)
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return nil, err
}
f, err := makeWin32File(h)
if err != nil {
windows.Close(h)
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return nil, err
}
// If the pipe is in message mode, return a message byte pipe, which
// supports CloseWrite().
if flags&cPIPE_TYPE_MESSAGE != 0 {
return &win32MessageBytePipe{
win32Pipe: win32Pipe{win32File: f, path: path},
}, nil
}
return &win32Pipe{win32File: f, path: path}, nil
}
type acceptResponse struct {
f *win32File
err error
}
type win32PipeListener struct {
firstHandle windows.Handle
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path string
config PipeConfig
acceptCh chan (chan acceptResponse)
closeCh chan int
doneCh chan int
}
func makeServerPipeHandle(path string, sd *windows.SECURITY_DESCRIPTOR, c *PipeConfig, first bool) (windows.Handle, error) {
path16, err := windows.UTF16FromString(path)
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if err != nil {
return 0, &os.PathError{Op: "open", Path: path, Err: err}
}
var oa objectAttributes
oa.Length = unsafe.Sizeof(oa)
var ntPath unicodeString
if err := rtlDosPathNameToNtPathName(&path16[0], &ntPath, 0, 0).Err(); err != nil {
return 0, &os.PathError{Op: "open", Path: path, Err: err}
}
defer windows.LocalFree(windows.Handle(ntPath.Buffer))
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oa.ObjectName = &ntPath
// The security descriptor is only needed for the first pipe.
if first {
if sd != nil {
oa.SecurityDescriptor = sd
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} else {
// Construct the default named pipe security descriptor.
var dacl uintptr
if err := rtlDefaultNpAcl(&dacl).Err(); err != nil {
return 0, fmt.Errorf("getting default named pipe ACL: %s", err)
}
defer windows.LocalFree(windows.Handle(dacl))
sd, err := windows.NewSecurityDescriptor()
if err != nil {
return 0, fmt.Errorf("creating new security descriptor: %s", err)
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}
if err = sd.SetDACL((*windows.ACL)(unsafe.Pointer(dacl)), true, false); err != nil {
return 0, fmt.Errorf("assigning dacl: %s", err)
}
sd, err = sd.ToSelfRelative()
if err != nil {
return 0, fmt.Errorf("converting to self-relative: %s", err)
}
oa.SecurityDescriptor = sd
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}
}
typ := uint32(cFILE_PIPE_REJECT_REMOTE_CLIENTS)
if c.MessageMode {
typ |= cFILE_PIPE_MESSAGE_TYPE
}
disposition := uint32(cFILE_OPEN)
access := uint32(windows.GENERIC_READ | windows.GENERIC_WRITE | windows.SYNCHRONIZE)
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if first {
disposition = cFILE_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
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}
timeout := int64(-50 * 10000) // 50ms
var (
h windows.Handle
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iosb ioStatusBlock
)
err = 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).Err()
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if err != nil {
return 0, &os.PathError{Op: "open", Path: path, Err: err}
}
runtime.KeepAlive(ntPath)
return h, nil
}
func (l *win32PipeListener) makeServerPipe() (*win32File, error) {
h, err := makeServerPipeHandle(l.path, nil, &l.config, false)
if err != nil {
return nil, err
}
f, err := makeWin32File(h)
if err != nil {
windows.Close(h)
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return nil, err
}
return f, nil
}
func (l *win32PipeListener) makeConnectedServerPipe() (*win32File, error) {
p, err := l.makeServerPipe()
if err != nil {
return nil, err
}
// Wait for the client to connect.
ch := make(chan error)
go func(p *win32File) {
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 == ErrFileClosed {
err = ErrPipeListenerClosed
}
}
return p, err
}
func (l *win32PipeListener) listenerRoutine() {
closed := false
for !closed {
select {
case <-l.closeCh:
closed = true
case responseCh := <-l.acceptCh:
var (
p *win32File
err error
)
for {
p, err = l.makeConnectedServerPipe()
// If the connection was immediately closed by the client, try
// again.
if err != windows.ERROR_NO_DATA {
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break
}
}
responseCh <- acceptResponse{p, err}
closed = err == ErrPipeListenerClosed
}
}
windows.Close(l.firstHandle)
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l.firstHandle = 0
// Notify Close() and Accept() callers that the handle has been closed.
close(l.doneCh)
}
// PipeConfig contain configuration for the pipe listener.
type PipeConfig struct {
// SecurityDescriptor contains a Windows security descriptor.
SecurityDescriptor *windows.SECURITY_DESCRIPTOR
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// 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 size the input buffer, in bytes.
InputBufferSize int32
// OutputBufferSize specifies the size the input buffer, in bytes.
OutputBufferSize int32
}
// ListenPipe creates a listener on a Windows named pipe path, e.g. \\.\pipe\mypipe.
// The pipe must not already exist.
func ListenPipe(path string, c *PipeConfig) (net.Listener, error) {
if c == nil {
c = &PipeConfig{}
}
h, err := makeServerPipeHandle(path, c.SecurityDescriptor, c, true)
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if err != nil {
return nil, err
}
l := &win32PipeListener{
firstHandle: h,
path: path,
config: *c,
acceptCh: make(chan (chan acceptResponse)),
closeCh: make(chan int),
doneCh: make(chan int),
}
go l.listenerRoutine()
return l, nil
}
func connectPipe(p *win32File) error {
c, err := p.prepareIo()
if err != nil {
return err
}
defer p.wg.Done()
err = connectNamedPipe(p.handle, &c.o)
_, err = p.asyncIo(c, nil, 0, err)
if err != nil && err != windows.ERROR_PIPE_CONNECTED {
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return err
}
return nil
}
func (l *win32PipeListener) 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 &win32MessageBytePipe{
win32Pipe: win32Pipe{win32File: response.f, path: l.path},
}, nil
}
return &win32Pipe{win32File: response.f, path: l.path}, nil
case <-l.doneCh:
return nil, ErrPipeListenerClosed
}
}
func (l *win32PipeListener) Close() error {
select {
case l.closeCh <- 1:
<-l.doneCh
case <-l.doneCh:
}
return nil
}
func (l *win32PipeListener) Addr() net.Addr {
return pipeAddress(l.path)
}