mirror of https://gogs.blitter.com/RLabs/xs
531 lines
15 KiB
Go
Executable File
531 lines
15 KiB
Go
Executable File
// hkexsh client
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//
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// Copyright (c) 2017-2018 Russell Magee
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// Licensed under the terms of the MIT license (see LICENSE.mit in this
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// distribution)
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//
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// golang implementation by Russ Magee (rmagee_at_gmail.com)
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package main
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import (
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"flag"
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"fmt"
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"io"
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"io/ioutil"
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"log"
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"os"
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"os/exec"
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"os/user"
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"path"
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"runtime"
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"strings"
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"sync"
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"syscall"
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hkexsh "blitter.com/go/hkexsh"
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"blitter.com/go/hkexsh/hkexnet"
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isatty "github.com/mattn/go-isatty"
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)
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type cmdSpec struct {
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op []byte
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who []byte
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cmd []byte
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authCookie []byte
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status int // UNIX exit status is uint8, but os.Exit() wants int
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}
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var (
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wg sync.WaitGroup
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)
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// Get terminal size using 'stty' command
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func GetSize() (cols, rows int, err error) {
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cmd := exec.Command("stty", "size")
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cmd.Stdin = os.Stdin
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out, err := cmd.Output()
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if err != nil {
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log.Println(err)
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cols, rows = 80, 24 //failsafe
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} else {
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fmt.Sscanf(string(out), "%d %d\n", &rows, &cols)
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}
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return
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}
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func parseNonSwitchArgs(a []string) (user, host, path string, isDest bool, otherArgs []string) {
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// Whether fancyArg is src or dst file depends on flag.Args() index;
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// fancyArg as last flag.Args() element denotes dstFile
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// fancyArg as not-last flag.Args() element denotes srcFile
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var fancyUser, fancyHost, fancyPath string
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for i, arg := range a {
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if strings.Contains(arg, ":") || strings.Contains(arg, "@") {
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fancyArg := strings.Split(flag.Arg(i), "@")
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var fancyHostPath []string
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if len(fancyArg) < 2 {
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//TODO: no user specified, use current
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fancyUser = "[default:getUser]"
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fancyHostPath = strings.Split(fancyArg[0], ":")
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} else {
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// user@....
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fancyUser = fancyArg[0]
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fancyHostPath = strings.Split(fancyArg[1], ":")
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}
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// [...@]host[:path]
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if len(fancyHostPath) > 1 {
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fancyPath = fancyHostPath[1]
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}
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fancyHost = fancyHostPath[0]
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//if fancyPath == "" {
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// fancyPath = "."
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//}
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if i == len(a)-1 {
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isDest = true
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fmt.Println("remote path isDest")
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}
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fmt.Println("fancyArgs: user:", fancyUser, "host:", fancyHost, "path:", fancyPath)
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} else {
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otherArgs = append(otherArgs, a[i])
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}
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}
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return fancyUser, fancyHost, fancyPath, isDest, otherArgs
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}
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// doCopyMode begins a secure hkexsh local<->remote file copy operation.
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func doCopyMode(conn *hkexnet.Conn, remoteDest bool, files string, rec *cmdSpec) (err error, exitStatus int) {
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if remoteDest {
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fmt.Println("local files:", files, "remote filepath:", string(rec.cmd))
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var c *exec.Cmd
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//os.Clearenv()
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//os.Setenv("HOME", u.HomeDir)
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//os.Setenv("TERM", "vt102") // TODO: server or client option?
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cmdName := "/bin/tar"
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cmdArgs := []string{"-cz", "-f", "/dev/stdout"}
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files = strings.TrimSpace(files)
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// Awesome fact: tar actually can take multiple -C args, and
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// changes to the dest dir *as it sees each one*. This enables
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// its use below, where clients can send scattered sets of source
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// files and dirs to be extraced to a single dest dir server-side,
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// whilst preserving the subtrees of dirs on the other side. :)
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// Eg., tar -c -f /dev/stdout -C /dirA fileInA -C /some/where/dirB fileInB /foo/dirC
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// packages fileInA, fileInB, and dirC at a single toplevel in the tar.
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// The tar authors are/were real smarties :)
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for _, v := range strings.Split(files, " ") {
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dirTmp, fileTmp := path.Split(v)
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cmdArgs = append(cmdArgs, "-C", dirTmp, fileTmp)
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//cmdArgs = append(cmdArgs, v)
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}
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fmt.Printf("[%v %v]\n", cmdName, cmdArgs)
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// NOTE the lack of quotes around --xform option's sed expression.
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// When args are passed in exec() format, no quoting is required
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// (as this isn't input from a shell) (right? -rlm 20180823)
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//cmdArgs := []string{"-xvz", "-C", files, `--xform=s#.*/\(.*\)#\1#`}
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c = exec.Command(cmdName, cmdArgs...)
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c.Dir, _ = os.Getwd()
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fmt.Println("[wd:", c.Dir, "]")
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c.Stdout = conn
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// Stderr sinkholing is important. Any extraneous output to tarpipe
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// messes up remote side as it's expecting pure tar data.
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// (For example, if user specifies abs paths, tar outputs
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// "Removing leading '/' from path names")
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c.Stderr = nil
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// Start the command (no pty)
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err = c.Start() // returns immediately
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if err != nil {
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fmt.Println(err)
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//log.Fatal(err)
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} else {
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if err = c.Wait(); err != nil {
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if exiterr, ok := err.(*exec.ExitError); ok {
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// The program has exited with an exit code != 0
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// This works on both Unix and Windows. Although package
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// syscall is generally platform dependent, WaitStatus is
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// defined for both Unix and Windows and in both cases has
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// an ExitStatus() method with the same signature.
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if status, ok := exiterr.Sys().(syscall.WaitStatus); ok {
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exitStatus = status.ExitStatus()
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log.Printf("Exit Status: %d", exitStatus)
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}
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}
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}
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fmt.Println("*** client->server cp finished ***")
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}
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} else {
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fmt.Println("remote filepath:", string(rec.cmd), "local files:", files)
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var c *exec.Cmd
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//os.Clearenv()
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//os.Setenv("HOME", u.HomeDir)
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//os.Setenv("TERM", "vt102") // TODO: server or client option?
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cmdName := "/bin/tar"
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destPath := files
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cmdArgs := []string{"-xz", "-C", destPath}
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fmt.Printf("[%v %v]\n", cmdName, cmdArgs)
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// NOTE the lack of quotes around --xform option's sed expression.
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// When args are passed in exec() format, no quoting is required
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// (as this isn't input from a shell) (right? -rlm 20180823)
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//cmdArgs := []string{"-xvz", "-C", destPath, `--xform=s#.*/\(.*\)#\1#`}
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c = exec.Command(cmdName, cmdArgs...)
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c.Stdin = conn
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c.Stdout = os.Stdout
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c.Stderr = os.Stderr
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// Start the command (no pty)
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err = c.Start() // returns immediately
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if err != nil {
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fmt.Println(err)
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//log.Fatal(err)
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} else {
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if err = c.Wait(); err != nil {
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if exiterr, ok := err.(*exec.ExitError); ok {
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// The program has exited with an exit code != 0
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// This works on both Unix and Windows. Although package
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// syscall is generally platform dependent, WaitStatus is
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// defined for both Unix and Windows and in both cases has
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// an ExitStatus() method with the same signature.
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if status, ok := exiterr.Sys().(syscall.WaitStatus); ok {
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exitStatus = status.ExitStatus()
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log.Printf("Exit Status: %d", exitStatus)
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}
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}
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}
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fmt.Println("*** server->client cp finished ***")
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}
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}
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return
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}
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// doShellMode begins an hkexsh shell session (one-shot command or interactive).
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func doShellMode(isInteractive bool, conn *hkexnet.Conn, oldState *hkexsh.State, rec *cmdSpec) {
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//client reader (from server) goroutine
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//Read remote end's stdout
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wg.Add(1)
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go func() {
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defer wg.Done()
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// By deferring a call to wg.Done(),
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// each goroutine guarantees that it marks
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// its direction's stream as finished.
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// io.Copy() expects EOF so normally this will
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// exit with inerr == nil
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_, inerr := io.Copy(os.Stdout, conn)
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if inerr != nil {
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fmt.Println(inerr)
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_ = hkexsh.Restore(int(os.Stdin.Fd()), oldState) // Best effort.
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os.Exit(1)
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}
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rec.status = int(conn.GetStatus())
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log.Println("rec.status:", rec.status)
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if isInteractive {
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log.Println("[* Got EOF *]")
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_ = hkexsh.Restore(int(os.Stdin.Fd()), oldState) // Best effort.
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}
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}()
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// Only look for data from stdin to send to remote end
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// for interactive sessions.
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if isInteractive {
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handleTermResizes(conn)
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// client writer (to server) goroutine
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// Write local stdin to remote end
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wg.Add(1)
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go func() {
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defer wg.Done()
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//!defer wg.Done()
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// Copy() expects EOF so this will
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// exit with outerr == nil
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//!_, outerr := io.Copy(conn, os.Stdin)
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_, outerr := func(conn *hkexnet.Conn, r io.Reader) (w int64, e error) {
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w, e = io.Copy(conn, r)
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return w, e
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}(conn, os.Stdin)
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if outerr != nil {
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log.Println(outerr)
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fmt.Println(outerr)
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_ = hkexsh.Restore(int(os.Stdin.Fd()), oldState) // Best effort.
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os.Exit(255)
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}
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log.Println("[Sent EOF]")
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}()
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}
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// Wait until both stdin and stdout goroutines finish before returning
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// (ensure client gets all data from server before closing)
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wg.Wait()
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}
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func UsageShell() {
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fmt.Fprintf(os.Stderr, "Usage of %s:\n", os.Args[0])
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fmt.Fprintf(os.Stderr, "%s [opts] [user]@server\n", os.Args[0])
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flag.PrintDefaults()
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}
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func UsageCp() {
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fmt.Fprintf(os.Stderr, "Usage of %s:\n", os.Args[0])
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fmt.Fprintf(os.Stderr, "%s [opts] srcFileOrDir [...] [user]@server[:dstpath]\n", os.Args[0])
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fmt.Fprintf(os.Stderr, "%s [opts] [user]@server[:srcFileOrDir] dstPath\n", os.Args[0])
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flag.PrintDefaults()
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}
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// hkexsh - a client for secure shell and file copy operations.
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//
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// While conforming to the basic net.Conn interface HKex.Conn has extra
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// capabilities designed to allow apps to define connection options,
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// encryption/hmac settings and operations across the encrypted channel.
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//
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// Initial setup is the same as using plain net.Dial(), but one may
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// specify extra extension tags (strings) to set the cipher and hmac
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// setting desired; as well as the intended operation mode for the
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// connection (app-specific, passed through to the server to use or
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// ignore at its discretion).
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func main() {
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version := "0.1pre (NO WARRANTY)"
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var vopt bool
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var dbg bool
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var shellMode bool // if true act as shell, else file copier
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var cAlg string
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var hAlg string
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var server string
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var port uint
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var cmdStr string
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var copySrc []byte
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var copyDst string
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var authCookie string
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var chaffEnabled bool
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var chaffFreqMin uint
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var chaffFreqMax uint
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var chaffBytesMax uint
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var op []byte
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isInteractive := false
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flag.BoolVar(&vopt, "v", false, "show version")
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flag.BoolVar(&dbg, "d", false, "debug logging")
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flag.StringVar(&cAlg, "c", "C_AES_256", "`cipher` [\"C_AES_256\" | \"C_TWOFISH_128\" | \"C_BLOWFISH_64\"]")
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flag.StringVar(&hAlg, "m", "H_SHA256", "`hmac` [\"H_SHA256\"]")
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flag.UintVar(&port, "p", 2000, "`port`")
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flag.StringVar(&authCookie, "a", "", "auth cookie")
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flag.BoolVar(&chaffEnabled, "e", true, "enabled chaff pkts (default true)")
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flag.UintVar(&chaffFreqMin, "f", 100, "chaff pkt `freq` min (msecs)")
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flag.UintVar(&chaffFreqMax, "F", 5000, "chaff pkt `freq` max (msecs)")
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flag.UintVar(&chaffBytesMax, "B", 64, "chaff pkt `size` max (bytes)")
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// Find out what program we are (shell or copier)
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myPath := strings.Split(os.Args[0], string(os.PathSeparator))
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if myPath[len(myPath)-1] != "hkexcp" && myPath[len(myPath)-1] != "hkexcp.exe" {
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// hkexsh accepts a command (-x) but not
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// a srcpath (-r) or dstpath (-t)
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flag.StringVar(&cmdStr, "x", "", "`command` to run (if not specified run interactive shell)")
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shellMode = true
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flag.Usage = UsageShell
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} else {
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flag.Usage = UsageCp
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}
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flag.Parse()
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remoteUser, tmpHost, tmpPath, pathIsDest, otherArgs :=
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parseNonSwitchArgs(flag.Args())
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fmt.Println("otherArgs:", otherArgs)
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// Set defaults if user doesn't specify user, path or port
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var uname string
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if remoteUser == "" {
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u, _ := user.Current()
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uname = u.Username
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} else {
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uname = remoteUser
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}
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if tmpHost != "" {
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server = tmpHost + ":" + fmt.Sprintf("%d", port)
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}
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if tmpPath == "" {
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tmpPath = "."
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}
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var fileArgs string
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if !shellMode /*&& tmpPath != ""*/ {
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// -if pathIsSrc && len(otherArgs) > 1 ERROR
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// -else flatten otherArgs into space-delim list => copySrc
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if pathIsDest {
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if len(otherArgs) == 0 {
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log.Fatal("ERROR: Must specify at least one dest path for copy")
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} else {
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for _, v := range otherArgs {
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copySrc = append(copySrc, ' ')
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copySrc = append(copySrc, v...)
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}
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copyDst = tmpPath
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fileArgs = string(copySrc)
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}
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} else {
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if len(otherArgs) == 0 {
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log.Fatal("ERROR: Must specify src path for copy")
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} else if len(otherArgs) == 1 {
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copyDst = otherArgs[0]
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if strings.Contains(copyDst, "*") || strings.Contains(copyDst, "?") {
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log.Fatal("ERROR: wildcards not allowed in dest path for copy")
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}
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} else {
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log.Fatal("ERROR: cannot specify more than one dest path for copy")
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}
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copySrc = []byte(tmpPath)
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fileArgs = copyDst
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}
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}
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// Do some more option consistency checks
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//fmt.Println("server finally is:", server)
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if flag.NFlag() == 0 && server == "" {
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flag.Usage()
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os.Exit(0)
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}
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if vopt {
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fmt.Printf("version v%s\n", version)
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os.Exit(0)
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}
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if len(cmdStr) != 0 && (len(copySrc) != 0 || len(copyDst) != 0) {
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log.Fatal("incompatible options -- either cmd (-x) or copy ops but not both")
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}
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//-------------------------------------------------------------------
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// Here we have parsed all options and can now carry out
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// either the shell session or copy operation.
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_ = shellMode
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if dbg {
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log.SetOutput(os.Stdout)
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} else {
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log.SetOutput(ioutil.Discard)
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}
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if shellMode {
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// We must make the decision about interactivity before Dial()
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// as it affects chaffing behaviour. 20180805
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if len(cmdStr) == 0 {
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op = []byte{'s'}
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isInteractive = true
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} else {
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op = []byte{'c'}
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// non-interactive cmds may complete quickly, so chaff earlier/faster
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// to help ensure there's some cover to the brief traffic.
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// (ignoring cmdline values)
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chaffFreqMin = 2
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chaffFreqMax = 10
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}
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} else {
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// as copy mode is also non-interactive, set up chaffing
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// just like the 'c' mode above
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chaffFreqMin = 2
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chaffFreqMax = 10
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|
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if pathIsDest {
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// client->server file copy
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// src file list is in copySrc
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op = []byte{'D'}
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fmt.Println("client->server copy:", string(copySrc), "->", copyDst)
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cmdStr = copyDst
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} else {
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// server->client file copy
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// remote src file(s) in copyDsr
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op = []byte{'S'}
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fmt.Println("server->client copy:", string(copySrc), "->", copyDst)
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cmdStr = string(copySrc)
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}
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}
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conn, err := hkexnet.Dial("tcp", server, cAlg, hAlg)
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if err != nil {
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fmt.Println("Err!")
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panic(err)
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}
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defer conn.Close()
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// From this point on, conn is a secure encrypted channel
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// Set stdin in raw mode if it's an interactive session
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// TODO: send flag to server side indicating this
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// affects shell command used
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var oldState *hkexsh.State
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if shellMode {
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if isatty.IsTerminal(os.Stdin.Fd()) {
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oldState, err = hkexsh.MakeRaw(int(os.Stdin.Fd()))
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if err != nil {
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panic(err)
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}
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defer func() { _ = hkexsh.Restore(int(os.Stdin.Fd()), oldState) }() // Best effort.
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} else {
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log.Println("NOT A TTY")
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}
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}
|
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|
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if len(authCookie) == 0 {
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fmt.Printf("Gimme cookie:")
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ab, err := hkexsh.ReadPassword(int(os.Stdin.Fd()))
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fmt.Printf("\r\n")
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if err != nil {
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panic(err)
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}
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authCookie = string(ab)
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// Security scrub
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ab = nil
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runtime.GC()
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}
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|
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rec := &cmdSpec{
|
|
op: op,
|
|
who: []byte(uname),
|
|
cmd: []byte(cmdStr),
|
|
authCookie: []byte(authCookie),
|
|
status: 0}
|
|
|
|
_, err = fmt.Fprintf(conn, "%d %d %d %d\n",
|
|
len(rec.op), len(rec.who), len(rec.cmd), len(rec.authCookie))
|
|
|
|
_, err = conn.Write(rec.op)
|
|
_, err = conn.Write(rec.who)
|
|
_, err = conn.Write(rec.cmd)
|
|
_, err = conn.Write(rec.authCookie)
|
|
|
|
// Set up chaffing to server
|
|
conn.SetupChaff(chaffFreqMin, chaffFreqMax, chaffBytesMax) // enable client->server chaffing
|
|
if chaffEnabled {
|
|
conn.EnableChaff()
|
|
defer conn.DisableChaff()
|
|
defer conn.ShutdownChaff()
|
|
}
|
|
|
|
if shellMode {
|
|
doShellMode(isInteractive, conn, oldState, rec)
|
|
} else {
|
|
doCopyMode(conn, pathIsDest, fileArgs, rec)
|
|
}
|
|
|
|
if oldState != nil {
|
|
_ = hkexsh.Restore(int(os.Stdin.Fd()), oldState) // Best effort.
|
|
}
|
|
|
|
os.Exit(rec.status)
|
|
}
|