Add support for libassuan file sockets (WinGnuPG support)

npiperelay.go

@@ -1,25 +1,30 @@
 package main
 
 import (
+	"bufio"
+	"errors"
 	"flag"
+	"fmt"
 	"io"
 	"log"
 	"os"
+	"strconv"
 	"sync"
-	"syscall"
 	"time"
 
 	"golang.org/x/sys/windows"
 )
 
-const cERROR_PIPE_NOT_CONNECTED syscall.Errno = 233
+// How long to sleep between failures while polling
+const pollTimeout = 200 * time.Millisecond
 
 var (
 	poll            = flag.Bool("p", false, "poll until the the named pipe exists")
 	closeWrite      = flag.Bool("s", false, "send a 0-byte message to the pipe after EOF on stdin")
 	closeOnEOF      = flag.Bool("ep", false, "terminate on EOF reading from the pipe, even if there is more data to write")
 	closeOnStdinEOF = flag.Bool("ei", false, "terminate on EOF reading from stdin, even if there is more data to write")
 	verbose         = flag.Bool("v", false, "verbose output on stderr")
+	assuan          = flag.Bool("a", false, "treat the target as a libassuan file socket (Used by GnuPG)")
 )
 
 func dialPipe(p string, poll bool) (*overlappedFile, error) {
@@ -33,13 +38,107 @@ func dialPipe(p string, poll bool) (*overlappedFile, error) {
 			return newOverlappedFile(h), nil
 		}
 		if poll && os.IsNotExist(err) {
-			time.Sleep(200 * time.Millisecond)
+			time.Sleep(pollTimeout)
 			continue
 		}
 		return nil, &os.PathError{Path: p, Op: "open", Err: err}
 	}
 }
 
+func dialPort(p int, poll bool) (*overlappedFile, error) {
+	if p < 0 || p > 65535 {
+		return nil, errors.New("Invalid port value")
+	}
+
+	h, err := windows.Socket(windows.AF_INET, windows.SOCK_STREAM, 0)
+	if err != nil {
+		return nil, err
+	}
+
+	// Create a SockaddrInet4 for connecting to
+	sa := &windows.SockaddrInet4{Addr: [4]byte{0x7F, 0x00, 0x00, 0x01}, Port: p}
+
+	// Bind to a randomly assigned local port
+	err = windows.Bind(h, &windows.SockaddrInet4{})
+	if err != nil {
+		return nil, err
+	}
+
+	// Wrap our socket up to be properly handled
+	conn := newOverlappedFile(h)
+
+	// Connect to the LibAssuan socket using overlapped ConnectEx operation
+	_, err = conn.asyncIo(func(h windows.Handle, n *uint32, o *windows.Overlapped) error {
+		return windows.ConnectEx(h, sa, nil, 0, nil, o)
+	})
+	if err != nil {
+		return nil, err
+	}
+
+	return conn, nil
+}
+
+// LibAssaun file socket: Attempt to read contents of the target file and connect to a TCP port
+func dialAssuan(p string, poll bool) (*overlappedFile, error) {
+	pipeConn, err := dialPipe(p, poll)
+	if err != nil {
+		return nil, err
+	}
+
+	var port int
+	var nonce [16]byte
+
+	reader := bufio.NewReader(pipeConn)
+
+	// Read the target port number from the first line
+	tmp, _, err := reader.ReadLine()
+	if err == nil {
+		port, err = strconv.Atoi(string(tmp))
+	}
+	if err != nil {
+		return nil, err
+	}
+
+	// Read the rest of the nonce from the file
+	n, err := reader.Read(nonce[:])
+	if err != nil {
+		return nil, err
+	}
+
+	if n != 16 {
+		err = fmt.Errorf("Read incorrect number of bytes for nonce. Expected 16, got %d (0x%X)", n, nonce)
+		return nil, err
+	}
+
+	if *verbose {
+		log.Printf("Port: %d, Nonce: %X", port, nonce)
+	}
+
+	pipeConn.Close()
+
+	for {
+		// Try to connect to the libassaun TCP socket hosted on localhost
+		conn, err := dialPort(port, poll)
+
+		if poll && (err == windows.WSAETIMEDOUT || err == windows.WSAECONNREFUSED || err == windows.WSAENETUNREACH || err == windows.ERROR_CONNECTION_REFUSED) {
+			time.Sleep(pollTimeout)
+			continue
+		}
+
+		if err != nil {
+			err = os.NewSyscallError("ConnectEx", err)
+			return nil, err
+		}
+
+		_, err = conn.Write(nonce[:])
+		if err != nil {
+			return nil, err
+		}
+
+		return conn, nil
+	}
+}
+
 func underlyingError(err error) error {
 	if serr, ok := err.(*os.SyscallError); ok {
 		return serr.Err
@@ -59,7 +158,14 @@ func main() {
 		log.Println("connecting to", args[0])
 	}
 
-	conn, err := dialPipe(args[0], *poll)
+	var conn *overlappedFile
+	var err error
+
+	if !*assuan {
+		conn, err = dialPipe(args[0], *poll)
+	} else {
+		conn, err = dialAssuan(args[0], *poll)
+	}
 	if err != nil {
 		log.Fatalln(err)
 	}
@@ -94,7 +200,7 @@ func main() {
 	}()
 
 	_, err = io.Copy(os.Stdout, conn)
-	if underlyingError(err) == windows.ERROR_BROKEN_PIPE || underlyingError(err) == cERROR_PIPE_NOT_CONNECTED {
+	if underlyingError(err) == windows.ERROR_BROKEN_PIPE || underlyingError(err) == windows.ERROR_PIPE_NOT_CONNECTED {
 		// The named pipe is closed and there is no more data to read. Since
 		// named pipes are not bidirectional, there is no way for the other side
 		// of the pipe to get more data, so do not wait for the stdin copy to

scripts/gpg-relay

@@ -0,0 +1,3 @@
+#!/bin/sh
+
+exec socat UNIX-LISTEN:/home/<your-username>/.gnupg/S.gpg-agent,fork, EXEC:'npiperelay.exe -ei -ep -s -a "C:/Users/<your-user-folder>/AppData/Roaming/gnupg/S.gpg-agent"',nofork