2fa2qr

#!/bin/bash
#
# Display a QR code for a 2fa token
#
# Requires the qrencode binary in $PATH
#
# Optional configuration environment variables - $DIR_2FA (default is ~)
#
# Optional command line argument - name of file to load from $DIR_2FA/ (default is .secret_2fa)
#
# Default is TOTP but if "#HOTP:TRUE" exists on a line in the file, HOTP will be used instead
#
# 2fa token can be pgp encrypted and it will be decrypted by the script

set -o nounset
#set -o verbose
#set -o pipefail
#set -o errexit

if [ ! "${DIR_2FA:-}" ]
then
  DIR_2FA=~
fi

if [ "${1:-}" ]
then
  KEYFILE="$DIR_2FA/${1:-}"
  label="${1:-}"
else
  KEYFILE="$DIR_2FA/.secret_2fa"
  label="default"
fi

if [ ! -e "$KEYFILE" ]
then
  echo "File not found: $KEYFILE"
  exit 3
fi

LAST_COUNTER_FILE=$DIR_2FA/".2fa-counter-${1:-}.txt"

if file --brief "$KEYFILE" | grep -q PGP
then
  SECRET_2FA="$(gpg --decrypt < "$KEYFILE" | grep -v ^\# | tr -d \ )"
else
  SECRET_2FA="$(grep -v ^\# "$KEYFILE" | tr -d \ )"
fi

HOTP=""
if grep -qx \#HOTP:TRUE "$KEYFILE"
then
  HOTP="true"
fi

if [ -e "$LAST_COUNTER_FILE" ]
then
  last_counter=$(cat $LAST_COUNTER_FILE)
  echo "Found last counter:"
  echo "$last_counter"
else
  last_counter="-1"
fi
new_counter=$last_counter

if [ "$HOTP" ]
then
  method=hotp
  counterkeyval="&counter=$new_counter"
else
  method=totp
  counterkeyval=""
fi
URL="otpauth://$method/$label?issuer=cli&secret=$SECRET_2FA$counterkeyval"

echo "$URL"
qrencode "$URL" -t ansi