Merge pull request #125 from jstarks/listenpipe

pipe: Fix ListenPipe/DialPipe race

pipe.go

@@ -5,9 +5,11 @@ package winio
 import (
 	"context"
 	"errors"
+	"fmt"
 	"io"
 	"net"
 	"os"
+	"runtime"
 	"syscall"
 	"time"
 	"unsafe"
@@ -19,6 +21,48 @@ import (
 //sys getNamedPipeInfo(pipe syscall.Handle, flags *uint32, outSize *uint32, inSize *uint32, maxInstances *uint32) (err error) = GetNamedPipeInfo
 //sys getNamedPipeHandleState(pipe syscall.Handle, state *uint32, curInstances *uint32, maxCollectionCount *uint32, collectDataTimeout *uint32, userName *uint16, maxUserNameSize uint32) (err error) = GetNamedPipeHandleStateW
 //sys localAlloc(uFlags uint32, length uint32) (ptr uintptr) = LocalAlloc
+//sys ntCreateNamedPipeFile(pipe *syscall.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
+//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 *securityDescriptor
+	SecurityQoS        uintptr
+}
+
+type unicodeString struct {
+	Length        uint16
+	MaximumLength uint16
+	Buffer        uintptr
+}
+
+type securityDescriptor struct {
+	Revision byte
+	Sbz1     byte
+	Control  uint16
+	Owner    uintptr
+	Group    uintptr
+	Sacl     uintptr
+	Dacl     uintptr
+}
+
+type ntstatus int32
+
+func (status ntstatus) Err() error {
+	if status >= 0 {
+		return nil
+	}
+	return rtlNtStatusToDosError(status)
+}
 
 const (
 	cERROR_PIPE_BUSY      = syscall.Errno(231)
@@ -26,21 +70,20 @@ const (
 	cERROR_PIPE_CONNECTED = syscall.Errno(535)
 	cERROR_SEM_TIMEOUT    = syscall.Errno(121)
 
-	cPIPE_ACCESS_DUPLEX            = 0x3
+	cSECURITY_SQOS_PRESENT = 0x100000
-	cFILE_FLAG_FIRST_PIPE_INSTANCE = 0x80000
+	cSECURITY_ANONYMOUS    = 0
-	cSECURITY_SQOS_PRESENT         = 0x100000
-	cSECURITY_ANONYMOUS            = 0
-
-	cPIPE_REJECT_REMOTE_CLIENTS = 0x8
-
-	cPIPE_UNLIMITED_INSTANCES = 255
-
-	cNMPWAIT_USE_DEFAULT_WAIT = 0
-	cNMPWAIT_NOWAIT           = 1
 
 	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
+
+	cSE_DACL_PRESENT = 4
 )
 
 var (
@@ -215,43 +258,87 @@ type acceptResponse struct {
 }
 
 type win32PipeListener struct {
-	firstHandle        syscall.Handle
+	firstHandle syscall.Handle
-	path               string
+	path        string
-	securityDescriptor []byte
+	config      PipeConfig
-	config             PipeConfig
+	acceptCh    chan (chan acceptResponse)
-	acceptCh           chan (chan acceptResponse)
+	closeCh     chan int
-	closeCh            chan int
+	doneCh      chan int
-	doneCh             chan int
 }
 
-func makeServerPipeHandle(path string, securityDescriptor []byte, c *PipeConfig, first bool) (syscall.Handle, error) {
+func makeServerPipeHandle(path string, sd []byte, c *PipeConfig, first bool) (syscall.Handle, error) {
-	var flags uint32 = cPIPE_ACCESS_DUPLEX | syscall.FILE_FLAG_OVERLAPPED
+	path16, err := syscall.UTF16FromString(path)
-	if first {
-		flags |= cFILE_FLAG_FIRST_PIPE_INSTANCE
-	}
-
-	var mode uint32 = cPIPE_REJECT_REMOTE_CLIENTS
-	if c.MessageMode {
-		mode |= cPIPE_TYPE_MESSAGE
-	}
-
-	sa := &syscall.SecurityAttributes{}
-	sa.Length = uint32(unsafe.Sizeof(*sa))
-	if securityDescriptor != nil {
-		len := uint32(len(securityDescriptor))
-		sa.SecurityDescriptor = localAlloc(0, len)
-		defer localFree(sa.SecurityDescriptor)
-		copy((*[0xffff]byte)(unsafe.Pointer(sa.SecurityDescriptor))[:], securityDescriptor)
-	}
-	h, err := createNamedPipe(path, flags, mode, cPIPE_UNLIMITED_INSTANCES, uint32(c.OutputBufferSize), uint32(c.InputBufferSize), 0, sa)
 	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 localFree(ntPath.Buffer)
+	oa.ObjectName = &ntPath
+
+	// The security descriptor is only needed for the first pipe.
+	if first {
+		if sd != nil {
+			len := uint32(len(sd))
+			sdb := localAlloc(0, len)
+			defer localFree(sdb)
+			copy((*[0xffff]byte)(unsafe.Pointer(sdb))[:], sd)
+			oa.SecurityDescriptor = (*securityDescriptor)(unsafe.Pointer(sdb))
+		} 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 localFree(dacl)
+
+			sdb := &securityDescriptor{
+				Revision: 1,
+				Control:  cSE_DACL_PRESENT,
+				Dacl:     dacl,
+			}
+			oa.SecurityDescriptor = sdb
+		}
+	}
+
+	typ := uint32(cFILE_PIPE_REJECT_REMOTE_CLIENTS)
+	if c.MessageMode {
+		typ |= cFILE_PIPE_MESSAGE_TYPE
+	}
+
+	disposition := uint32(cFILE_OPEN)
+	access := uint32(syscall.GENERIC_READ | syscall.GENERIC_WRITE | syscall.SYNCHRONIZE)
+	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 = syscall.SYNCHRONIZE
+	}
+
+	timeout := int64(-50 * 10000) // 50ms
+
+	var (
+		h    syscall.Handle
+		iosb ioStatusBlock
+	)
+	err = ntCreateNamedPipeFile(&h, access, &oa, &iosb, syscall.FILE_SHARE_READ|syscall.FILE_SHARE_WRITE, disposition, 0, typ, 0, 0, 0xffffffff, uint32(c.InputBufferSize), uint32(c.OutputBufferSize), &timeout).Err()
+	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, l.securityDescriptor, &l.config, false)
+	h, err := makeServerPipeHandle(l.path, nil, &l.config, false)
 	if err != nil {
 		return nil, err
 	}
@@ -362,32 +449,13 @@ func ListenPipe(path string, c *PipeConfig) (net.Listener, error) {
 	if err != nil {
 		return nil, err
 	}
-	// Create a client handle and connect it.  This results in the pipe
-	// instance always existing, so that clients see ERROR_PIPE_BUSY
-	// rather than ERROR_FILE_NOT_FOUND.  This ties the first instance
-	// up so that no other instances can be used.  This would have been
-	// cleaner if the Win32 API matched CreateFile with ConnectNamedPipe
-	// instead of CreateNamedPipe.  (Apparently created named pipes are
-	// considered to be in listening state regardless of whether any
-	// active calls to ConnectNamedPipe are outstanding.)
-	h2, err := createFile(path, 0, 0, nil, syscall.OPEN_EXISTING, cSECURITY_SQOS_PRESENT|cSECURITY_ANONYMOUS, 0)
-	if err != nil {
-		syscall.Close(h)
-		return nil, err
-	}
-	// Close the client handle. The server side of the instance will
-	// still be busy, leading to ERROR_PIPE_BUSY instead of
-	// ERROR_NOT_FOUND, as long as we don't close the server handle,
-	// or disconnect the client with DisconnectNamedPipe.
-	syscall.Close(h2)
 	l := &win32PipeListener{
-		firstHandle:        h,
+		firstHandle: h,
-		path:               path,
+		path:        path,
-		securityDescriptor: sd,
+		config:      *c,
-		config:             *c,
+		acceptCh:    make(chan (chan acceptResponse)),
-		acceptCh:           make(chan (chan acceptResponse)),
+		closeCh:     make(chan int),
-		closeCh:            make(chan int),
+		doneCh:      make(chan int),
-		doneCh:             make(chan int),
 	}
 	go l.listenerRoutine()
 	return l, nil

pipe_test.go

@@ -549,3 +549,24 @@ func TestMessageReadMode(t *testing.T) {
 		t.Fatalf("expected %s: %s", msg, vmsg)
 	}
 }
+
+func TestListenConnectRace(t *testing.T) {
+	for i := 0; i < 50 && !t.Failed(); i++ {
+		var wg sync.WaitGroup
+		wg.Add(1)
+		go func() {
+			c, err := DialPipe(testPipeName, nil)
+			if err == nil {
+				c.Close()
+			}
+			wg.Done()
+		}()
+		s, err := ListenPipe(testPipeName, nil)
+		if err != nil {
+			t.Error(i, err)
+		} else {
+			s.Close()
+		}
+		wg.Wait()
+	}
+}

zsyscall_windows.go

@@ -1,4 +1,4 @@
-// MACHINE GENERATED BY 'go generate' COMMAND; DO NOT EDIT
+// Code generated by 'go generate'; DO NOT EDIT.
 
 package winio
 
@@ -38,6 +38,7 @@ func errnoErr(e syscall.Errno) error {
 
 var (
 	modkernel32 = windows.NewLazySystemDLL("kernel32.dll")
+	modntdll    = windows.NewLazySystemDLL("ntdll.dll")
 	modadvapi32 = windows.NewLazySystemDLL("advapi32.dll")
 
 	procCancelIoEx                                           = modkernel32.NewProc("CancelIoEx")
@@ -47,10 +48,13 @@ var (
 	procConnectNamedPipe                                     = modkernel32.NewProc("ConnectNamedPipe")
 	procCreateNamedPipeW                                     = modkernel32.NewProc("CreateNamedPipeW")
 	procCreateFileW                                          = modkernel32.NewProc("CreateFileW")
-	procWaitNamedPipeW                                       = modkernel32.NewProc("WaitNamedPipeW")
 	procGetNamedPipeInfo                                     = modkernel32.NewProc("GetNamedPipeInfo")
 	procGetNamedPipeHandleStateW                             = modkernel32.NewProc("GetNamedPipeHandleStateW")
 	procLocalAlloc                                           = modkernel32.NewProc("LocalAlloc")
+	procNtCreateNamedPipeFile                                = modntdll.NewProc("NtCreateNamedPipeFile")
+	procRtlNtStatusToDosErrorNoTeb                           = modntdll.NewProc("RtlNtStatusToDosErrorNoTeb")
+	procRtlDosPathNameToNtPathName_U                         = modntdll.NewProc("RtlDosPathNameToNtPathName_U")
+	procRtlDefaultNpAcl                                      = modntdll.NewProc("RtlDefaultNpAcl")
 	procLookupAccountNameW                                   = modadvapi32.NewProc("LookupAccountNameW")
 	procConvertSidToStringSidW                               = modadvapi32.NewProc("ConvertSidToStringSidW")
 	procConvertStringSecurityDescriptorToSecurityDescriptorW = modadvapi32.NewProc("ConvertStringSecurityDescriptorToSecurityDescriptorW")
@@ -176,27 +180,6 @@ func _createFile(name *uint16, access uint32, mode uint32, sa *syscall.SecurityA
 	return
 }
 
-func waitNamedPipe(name string, timeout uint32) (err error) {
-	var _p0 *uint16
-	_p0, err = syscall.UTF16PtrFromString(name)
-	if err != nil {
-		return
-	}
-	return _waitNamedPipe(_p0, timeout)
-}
-
-func _waitNamedPipe(name *uint16, timeout uint32) (err error) {
-	r1, _, e1 := syscall.Syscall(procWaitNamedPipeW.Addr(), 2, uintptr(unsafe.Pointer(name)), uintptr(timeout), 0)
-	if r1 == 0 {
-		if e1 != 0 {
-			err = errnoErr(e1)
-		} else {
-			err = syscall.EINVAL
-		}
-	}
-	return
-}
-
 func getNamedPipeInfo(pipe syscall.Handle, flags *uint32, outSize *uint32, inSize *uint32, maxInstances *uint32) (err error) {
 	r1, _, e1 := syscall.Syscall6(procGetNamedPipeInfo.Addr(), 5, uintptr(pipe), uintptr(unsafe.Pointer(flags)), uintptr(unsafe.Pointer(outSize)), uintptr(unsafe.Pointer(inSize)), uintptr(unsafe.Pointer(maxInstances)), 0)
 	if r1 == 0 {
@@ -227,6 +210,32 @@ func localAlloc(uFlags uint32, length uint32) (ptr uintptr) {
 	return
 }
 
+func ntCreateNamedPipeFile(pipe *syscall.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) {
+	r0, _, _ := syscall.Syscall15(procNtCreateNamedPipeFile.Addr(), 14, uintptr(unsafe.Pointer(pipe)), uintptr(access), uintptr(unsafe.Pointer(oa)), uintptr(unsafe.Pointer(iosb)), uintptr(share), uintptr(disposition), uintptr(options), uintptr(typ), uintptr(readMode), uintptr(completionMode), uintptr(maxInstances), uintptr(inboundQuota), uintptr(outputQuota), uintptr(unsafe.Pointer(timeout)), 0)
+	status = ntstatus(r0)
+	return
+}
+
+func rtlNtStatusToDosError(status ntstatus) (winerr error) {
+	r0, _, _ := syscall.Syscall(procRtlNtStatusToDosErrorNoTeb.Addr(), 1, uintptr(status), 0, 0)
+	if r0 != 0 {
+		winerr = syscall.Errno(r0)
+	}
+	return
+}
+
+func rtlDosPathNameToNtPathName(name *uint16, ntName *unicodeString, filePart uintptr, reserved uintptr) (status ntstatus) {
+	r0, _, _ := syscall.Syscall6(procRtlDosPathNameToNtPathName_U.Addr(), 4, uintptr(unsafe.Pointer(name)), uintptr(unsafe.Pointer(ntName)), uintptr(filePart), uintptr(reserved), 0, 0)
+	status = ntstatus(r0)
+	return
+}
+
+func rtlDefaultNpAcl(dacl *uintptr) (status ntstatus) {
+	r0, _, _ := syscall.Syscall(procRtlDefaultNpAcl.Addr(), 1, uintptr(unsafe.Pointer(dacl)), 0, 0)
+	status = ntstatus(r0)
+	return
+}
+
 func lookupAccountName(systemName *uint16, accountName string, sid *byte, sidSize *uint32, refDomain *uint16, refDomainSize *uint32, sidNameUse *uint32) (err error) {
 	var _p0 *uint16
 	_p0, err = syscall.UTF16PtrFromString(accountName)