Updates #3802 Change-Id: Iabc07c00c7e4f43944cfe7daec8d2b66ac002289 Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>main
Brad Fitzpatrick
4 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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