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Merge pull request #125 from jstarks/listenpipe

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pipe: Fix ListenPipe/DialPipe race
This commit is contained in:
John Howard
2019-04-08 10:36:21 -07:00
committed by GitHub
parent b30741e1fe bd71ef0e5d
commit 84b4ab48a5
3 changed files with 185 additions and 87 deletions
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pipe.go
+132 -64
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@@ -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
cFILE_FLAG_FIRST_PIPE_INSTANCE = 0x80000
cSECURITY_SQOS_PRESENT = 0x100000
cSECURITY_ANONYMOUS = 0
cPIPE_REJECT_REMOTE_CLIENTS = 0x8
cPIPE_UNLIMITED_INSTANCES = 255
cNMPWAIT_USE_DEFAULT_WAIT = 0
cNMPWAIT_NOWAIT = 1
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
cSE_DACL_PRESENT = 4
)
var (
@@ -215,43 +258,87 @@ type acceptResponse struct {
}
type win32PipeListener struct {
firstHandle syscall.Handle
path string
securityDescriptor []byte
config PipeConfig
acceptCh chan (chan acceptResponse)
closeCh chan int
doneCh chan int
firstHandle syscall.Handle
path string
config PipeConfig
acceptCh chan (chan acceptResponse)
closeCh chan int
doneCh chan int
}
func makeServerPipeHandle(path string, securityDescriptor []byte, c *PipeConfig, first bool) (syscall.Handle, error) {
var flags uint32 = cPIPE_ACCESS_DUPLEX | syscall.FILE_FLAG_OVERLAPPED
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)
func makeServerPipeHandle(path string, sd []byte, c *PipeConfig, first bool) (syscall.Handle, error) {
path16, err := syscall.UTF16FromString(path)
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,
path: path,
securityDescriptor: sd,
config: *c,
acceptCh: make(chan (chan acceptResponse)),
closeCh: make(chan int),
doneCh: make(chan int),
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