tailscale/safesocket/safesocket_darwin.go

147 lines
4.6 KiB
Go
Raw Permalink Normal View History

// Copyright (c) 2021 Tailscale Inc & AUTHORS All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package safesocket
import (
"bufio"
"bytes"
"errors"
"fmt"
"io/ioutil"
"os"
"os/exec"
"path/filepath"
"strconv"
"strings"
"sync"
)
func init() {
localTCPPortAndToken = localTCPPortAndTokenDarwin
}
// localTCPPortAndTokenMacsys returns the localhost TCP port number and auth token
// from /Library/Tailscale.
//
// In that case the files are:
// /Library/Tailscale/ipnport => $port (symlink with localhost port number target)
// /Library/Tailscale/sameuserproof-$port is a file with auth
func localTCPPortAndTokenMacsys() (port int, token string, err error) {
const dir = "/Library/Tailscale"
portStr, err := os.Readlink(filepath.Join(dir, "ipnport"))
if err != nil {
return 0, "", err
}
port, err = strconv.Atoi(portStr)
if err != nil {
return 0, "", err
}
authb, err := os.ReadFile(filepath.Join(dir, "sameuserproof-"+portStr))
if err != nil {
return 0, "", err
}
auth := strings.TrimSpace(string(authb))
if auth == "" {
return 0, "", errors.New("empty auth token in sameuserproof file")
}
return port, auth, nil
}
var warnAboutRootOnce sync.Once
func localTCPPortAndTokenDarwin() (port int, token string, err error) {
// There are two ways this binary can be run: as the Mac App Store sandboxed binary,
// or a normal binary that somebody built or download and are being run from outside
// the sandbox. Detect which way we're running and then figure out how to connect
// to the local daemon.
if dir := os.Getenv("TS_MACOS_CLI_SHARED_DIR"); dir != "" {
// First see if we're running as the non-AppStore "macsys" variant.
if strings.Contains(os.Getenv("HOME"), "/Containers/io.tailscale.ipn.macsys/") {
if port, token, err := localTCPPortAndTokenMacsys(); err == nil {
return port, token, nil
}
}
// The current binary (this process) is sandboxed. The user is
// running the CLI via /Applications/Tailscale.app/Contents/MacOS/Tailscale
// which sets the TS_MACOS_CLI_SHARED_DIR environment variable.
fis, err := ioutil.ReadDir(dir)
if err != nil {
return 0, "", err
}
for _, fi := range fis {
name := filepath.Base(fi.Name())
// Look for name like "sameuserproof-61577-2ae2ec9e0aa2005784f1"
// to extract out the port number and token.
if strings.HasPrefix(name, "sameuserproof-") {
f := strings.SplitN(name, "-", 3)
if len(f) == 3 {
if port, err := strconv.Atoi(f[1]); err == nil {
return port, f[2], nil
}
}
}
}
if os.Geteuid() == 0 {
// Log a warning as the clue to the user, in case the error
// message is swallowed. Only do this once since we may retry
// multiple times to connect, and don't want to spam.
warnAboutRootOnce.Do(func() {
fmt.Fprintf(os.Stderr, "Warning: The CLI is running as root from within a sandboxed binary. It cannot reach the local tailscaled, please try again as a regular user.\n")
})
}
return 0, "", fmt.Errorf("failed to find sandboxed sameuserproof-* file in TS_MACOS_CLI_SHARED_DIR %q", dir)
}
// The current process is running outside the sandbox, so use
// lsof to find the IPNExtension (the Mac App Store variant).
cmd := exec.Command("lsof",
"-n", // numeric sockets; don't do DNS lookups, etc
"-a", // logical AND remaining options
fmt.Sprintf("-u%d", os.Getuid()), // process of same user only
"-c", "IPNExtension", // starting with IPNExtension
"-F", // machine-readable output
)
out, err := cmd.Output()
if err != nil {
// Before returning an error, see if we're running the
// macsys variant at the normal location.
if port, token, err := localTCPPortAndTokenMacsys(); err == nil {
return port, token, nil
}
return 0, "", fmt.Errorf("failed to run '%s' looking for IPNExtension: %w", cmd, err)
}
bs := bufio.NewScanner(bytes.NewReader(out))
subStr := []byte(".tailscale.ipn.macos/sameuserproof-")
for bs.Scan() {
line := bs.Bytes()
i := bytes.Index(line, subStr)
if i == -1 {
continue
}
f := strings.SplitN(string(line[i+len(subStr):]), "-", 2)
if len(f) != 2 {
continue
}
portStr, token := f[0], f[1]
port, err := strconv.Atoi(portStr)
if err != nil {
return 0, "", fmt.Errorf("invalid port %q found in lsof", portStr)
}
return port, token, nil
}
// Before returning an error, see if we're running the
// macsys variant at the normal location.
if port, token, err := localTCPPortAndTokenMacsys(); err == nil {
return port, token, nil
}
return 0, "", ErrTokenNotFound
}