PIN inject script for openvpn PKCS11 smart cards

inject-pin.sh

#!/bin/bash

cd /etc/openvpn

function waitforport {
  i=0
  # Wait for openvpn management interface
  while ! timeout 1 bash -c 'cat < /dev/null > /dev/tcp/127.0.0.1/8888' 2> /dev/null; do
    i=$((i+1))
    if [ $i -gt 10 ]; then
        echo "Timeout waiting for openvpn management interface" 1>&2
        exit 1
    fi
    sleep 1
  done
}

function injectloop {
  PIN=$(head -1 pin.txt)

  exec 3<>/dev/tcp/127.0.0.1/8888
  # Send management password
  head -1 management.pwd >&3

  # read anything it sends
  while read -r -u 3; do
    # First, release hold
    if [[ $REPLY == ?HOLD:Waiting* ]]; then
      echo 'hold release' >&3
    # if it asks for a password, then give it one
    elif [[ $REPLY == ?PASSWORD:Need* ]]; then
      PWTYPE=$(echo $REPLY | sed -e "s/^[^']*'//;s/'.*$//")
      echo 'Received password requested, injecting PIN' >&2
      echo 'password "'$PWTYPE'" '"$PIN" >&3
    elif [[ $REPLY == *"password entered, but not yet verified"* ]]; then
      echo "All done: $REPLY" >&2
      echo "quit" >&3
    else
      echo "Ignoring message: $REPLY" >&2
    fi
  done
}

(
  # wait for lock on /run/lock/inject-pin (fd 200) for 10 seconds
  flock -x -w 10 200 || exit 1
  while [ 1 ]; do 
    waitforport
    injectloop
  done
) 200>/run/lock/inject-pin