mirror of https://github.com/tailscale/tailscale/
cmd/tailscale/cli: add start of 'ssh' subcommand
Updates #3802 Change-Id: Iabc07c00c7e4f43944cfe7daec8d2b66ac002289 Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>pull/4284/head
Brad Fitzpatrick
2 years ago
committed by
Brad Fitzpatrick
parent
06fcf3b225
commit
8294915780
@ -0,0 +1,97 @@
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// Copyright (c) 2022 Tailscale Inc & AUTHORS All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package cli
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import (
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"context"
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"errors"
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"fmt"
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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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"runtime"
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"strings"
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"syscall"
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"github.com/alessio/shellescape"
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"github.com/peterbourgon/ff/v3/ffcli"
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"tailscale.com/envknob"
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)
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var sshCmd = &ffcli.Command{
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Name: "ssh",
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ShortUsage: "ssh [user@]<host> [args...]",
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ShortHelp: "SSH to a Tailscale machine",
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Exec: runSSH,
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}
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func runSSH(ctx context.Context, args []string) error {
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if len(args) == 0 {
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return errors.New("usage: ssh [user@]<host>")
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}
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arg, argRest := args[0], args[1:]
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username, host, ok := strings.Cut(arg, "@")
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if !ok {
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host = arg
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lu, err := user.Current()
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if err != nil {
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return nil
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}
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username = lu.Username
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}
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ssh, err := exec.LookPath("ssh")
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if err != nil {
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// TODO(bradfitz): use Go's crypto/ssh client instead
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// of failing. But for now:
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return fmt.Errorf("no system 'ssh' command found: %w", err)
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}
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tailscaleBin, err := os.Executable()
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if err != nil {
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return err
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}
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argv := append([]string{
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ssh,
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"-o", fmt.Sprintf("ProxyCommand %s --socket=%s nc %%h %%p",
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shellescape.Quote(tailscaleBin),
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shellescape.Quote(rootArgs.socket),
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),
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// Explicitly rebuild the user@host argument rather than
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// passing it through. In general, the use of OpenSSH's ssh
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// binary is a crutch for now. We don't want to be
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// Hyrum-locked into passing through all OpenSSH flags to the
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// OpenSSH client forever. We try to make our flags and args
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// be compatible, but only a subset. The "tailscale ssh"
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// command should be a simple and portable one. If they want
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// to use a different one, we'll later be making stock ssh
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// work well by default too. (doing things like automatically
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// setting known_hosts, etc)
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username + "@" + host,
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}, argRest...)
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if runtime.GOOS == "windows" {
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// Don't use syscall.Exec on Windows.
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cmd := exec.Command(ssh, argv[1:]...)
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cmd.Stderr = os.Stderr
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cmd.Stdout = os.Stdout
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cmd.Stderr = os.Stderr
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var ee *exec.ExitError
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err := cmd.Run()
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if errors.As(err, &ee) {
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os.Exit(ee.ExitCode())
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}
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return err
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}
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if envknob.Bool("TS_DEBUG_SSH_EXEC") {
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log.Printf("Running: %q, %q ...", ssh, argv)
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}
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if err := syscall.Exec(ssh, argv, os.Environ()); err != nil {
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return err
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}
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return errors.New("unreachable")
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}
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