96 lines
2.7 KiB
Go
96 lines
2.7 KiB
Go
// Copyright (c) Tailscale Inc & AUTHORS
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// SPDX-License-Identifier: BSD-3-Clause
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//go:build !windows && !js && !plan9
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package safesocket
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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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"net"
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"os"
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"os/exec"
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"path/filepath"
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"runtime"
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)
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func connect(ctx context.Context, path string) (net.Conn, error) {
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if runtime.GOOS == "js" {
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return nil, errors.New("safesocket.Connect not yet implemented on js/wasm")
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}
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var std net.Dialer
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return std.DialContext(ctx, "unix", path)
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}
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func listen(path string) (net.Listener, error) {
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// Unix sockets hang around in the filesystem even after nobody
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// is listening on them. (Which is really unfortunate but long-
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// entrenched semantics.) Try connecting first; if it works, then
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// the socket is still live, so let's not replace it. If it doesn't
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// work, then replace it.
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//
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// Note that there's a race condition between these two steps. A
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// "proper" daemon usually uses a dance involving pidfiles to first
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// ensure that no other instances of itself are running, but that's
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// beyond the scope of our simple socket library.
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c, err := net.Dial("unix", path)
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if err == nil {
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c.Close()
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if tailscaledRunningUnderLaunchd() {
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return nil, fmt.Errorf("%v: address already in use; tailscaled already running under launchd (to stop, run: $ sudo launchctl stop com.tailscale.tailscaled)", path)
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}
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return nil, fmt.Errorf("%v: address already in use", path)
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}
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_ = os.Remove(path)
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perm := socketPermissionsForOS()
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sockDir := filepath.Dir(path)
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if _, err := os.Stat(sockDir); os.IsNotExist(err) {
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os.MkdirAll(sockDir, 0755) // best effort
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// If we're on a platform where we want the socket
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// world-readable, open up the permissions on the
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// just-created directory too, in case a umask ate
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// it. This primarily affects running tailscaled by
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// hand as root in a shell, as there is no umask when
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// running under systemd.
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if perm == 0666 {
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if fi, err := os.Stat(sockDir); err == nil && fi.Mode()&0077 == 0 {
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if err := os.Chmod(sockDir, 0755); err != nil {
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log.Print(err)
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}
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}
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}
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}
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pipe, err := net.Listen("unix", path)
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if err != nil {
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return nil, err
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}
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os.Chmod(path, perm)
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return pipe, err
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}
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func tailscaledRunningUnderLaunchd() bool {
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if runtime.GOOS != "darwin" {
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return false
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}
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plist, err := exec.Command("launchctl", "list", "com.tailscale.tailscaled").Output()
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_ = plist // parse it? https://github.com/DHowett/go-plist if we need something.
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running := err == nil
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return running
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}
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// socketPermissionsForOS returns the permissions to use for the
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// tailscaled.sock.
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func socketPermissionsForOS() os.FileMode {
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if PlatformUsesPeerCreds() {
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return 0666
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}
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// Otherwise, root only.
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return 0600
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}
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