Socat-based root tunnel: let an AI agent run root commands without sharing your sudo password

sudo-tunnel.sh

#!/usr/bin/env bash
set -euo pipefail

SOCK="${XDG_RUNTIME_DIR:-/tmp}/sudo-tunnel-$(id -u).sock"
ME="$(id -un)"

if [ "$(id -u)" = "0" ]; then
  echo "Run as your normal user, not with sudo/root." >&2
  exit 1
fi

if [ -S "$SOCK" ] && printf 'exit\n' | timeout 2 nc -N -U "$SOCK" >/dev/null 2>&1; then
  echo "Tunnel already running: $SOCK" >&2
  exit 1
fi
rm -f "$SOCK"

echo "Enter your sudo password (it never leaves this terminal):"
sudo -v

if ! command -v socat >/dev/null 2>&1; then
  echo "Installing socat ..."
  sudo apt-get install -y socat
fi
if ! command -v nc >/dev/null 2>&1; then
  echo "Missing nc: sudo apt-get install -y netcat-openbsd" >&2
  exit 1
fi

sudo socat "UNIX-LISTEN:$SOCK,fork,mode=600,user=$ME,group=$ME" EXEC:'/bin/bash',stderr </dev/null &
JOB=$!

ready=0
for _ in $(seq 1 50); do
  if [ -S "$SOCK" ]; then ready=1; break; fi
  [ -e "/proc/$JOB" ] || break
  sleep 0.1
done

if [ "$ready" != "1" ]; then
  echo "socat failed to start." >&2
  sudo -n pkill -f "UNIX-LISTEN:$SOCK" >/dev/null 2>&1 || true
  rm -f "$SOCK"
  exit 1
fi

if [ "$(printf 'id -u\n' | timeout 5 nc -N -U "$SOCK" 2>/dev/null | tr -d '\r\n ')" != "0" ]; then
  echo "Self-test failed: tunnel is not root." >&2
  sudo -n pkill -f "UNIX-LISTEN:$SOCK" >/dev/null 2>&1 || true
  rm -f "$SOCK"
  exit 1
fi

cleanup() {
  rm -f "$SOCK"
  sudo -n pkill -f "UNIX-LISTEN:$SOCK" >/dev/null 2>&1 || true
  echo
  echo "Tunnel closed, root access revoked."
}
trap cleanup EXIT
trap 'exit 0' INT TERM

cat <<EOF

============================================================
 Root tunnel up: $SOCK
 Ctrl+C to close and revoke root access.
============================================================

Paste to agent:

Root tunnel is open (do not use sudo):
printf 'COMMAND\n' | timeout 30 nc -N -U $SOCK
EOF

wait "$JOB" || true