Mitchell-JohnsonandClaude Fable 5.1
468f45251d
The Mac mini's daemon started while the machine was still booting, sudo -n true took longer than the 3 s timeout, and sync.Once kept the answer: no root, so the next self-update could not replace the binary. Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
93 lines
2.6 KiB
Go
93 lines
2.6 KiB
Go
// Package priv is the one place that knows how this daemon gets root: it already is root,
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// or it has passwordless sudo, or passwordless doas (Alpine, some BSD-minded setups), or
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// it has nothing and the privileged features stay off.
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package priv
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import (
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"context"
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"os"
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"os/exec"
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"strings"
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"sync"
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"time"
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)
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var (
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mu sync.Mutex
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mode string // "root" | "sudo" | "doas" | ""
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prefix []string
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probed time.Time
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reprobe = 30 * time.Second
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)
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// detect settles how root is reached. Finding a way is remembered for good; finding none
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// is only believed for a while, because the probe can fail for reasons that pass — sudo
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// taking longer than the timeout on a machine that is still booting left a daemon
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// convinced it had no root until its next restart.
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func detect() {
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mu.Lock()
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defer mu.Unlock()
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if mode != "" || (!probed.IsZero() && time.Since(probed) < reprobe) {
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return
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}
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probed = time.Now()
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if os.Geteuid() == 0 {
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mode = "root"
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return
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}
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for _, tool := range []string{"sudo", "doas"} {
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if _, err := exec.LookPath(tool); err != nil {
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continue
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}
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ctx, cancel := context.WithTimeout(context.Background(), 3*time.Second)
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err := exec.CommandContext(ctx, tool, "-n", "true").Run()
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cancel()
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if err == nil {
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mode, prefix = tool, []string{tool, "-n"}
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return
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}
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}
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}
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// Mode reports how root is reached: "root", "sudo", "doas", or "" when it can't be.
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func Mode() string { detect(); mu.Lock(); defer mu.Unlock(); return mode }
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// Available reports whether commands can be run as root without a prompt.
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func Available() bool { return Mode() != "" }
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// Wrap returns args prefixed so they run as root. Without privilege it returns args
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// unchanged; callers gate on Available() where that matters.
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func Wrap(args ...string) []string {
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detect()
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mu.Lock()
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defer mu.Unlock()
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return append(append([]string{}, prefix...), args...)
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}
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// AsUser returns args prefixed so they run as another user with that user's HOME.
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func AsUser(user string, args ...string) []string {
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switch Mode() {
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case "sudo":
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return append([]string{"sudo", "-n", "-u", user, "-H"}, args...)
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case "doas":
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return append([]string{"doas", "-n", "-u", user}, args...)
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case "root":
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if user == "root" {
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return args
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}
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// su exists everywhere (util-linux, shadow, busybox), needs no password from root
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// and sets HOME for the target user.
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return []string{"su", "-s", "/bin/sh", user, "-c", Quote(args)}
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}
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return args
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}
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// Quote joins args into one POSIX shell command line.
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func Quote(args []string) string {
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q := make([]string, len(args))
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for i, a := range args {
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q[i] = "'" + strings.ReplaceAll(a, "'", `'\''`) + "'"
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}
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return strings.Join(q, " ")
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}
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