#!/bin/bash
#===============================================================================
#
# DIRECTORY:
#   /home/*/.local/share/nautilus/scripts/01-verify/
# OR
#   /home/*/.gnome2/nautilus-sctipts/01-verify/ (deprecated)
#
# FILE:
#   03-freetsa-verify
#
# USAGE:
#   Right klick on the first file of an EWF image and
#   choose this nautilus script from the context menu.
#
# OPTIONS:
#   none
#
# DESCRIPTION:
#   Verifies that the content of a log file has not been changed after a
#   specific date.
#
# REQUIREMENTS:
#   bash, zenity, curl and openssl
#
# BUGS:
#   ---
#
# NOTES:
#   Tested on
#   - Arch Linux
#
# AUTHOR:
#   Patrick Neumann, patrick@neumannsland.de
#
# COMPANY:
#   (privately)
#
# VERSION:
#   0.9 (beta)
#
# LINK TO THE MOST CURRENT VERSIONS:
#   https://...
#
# CREATED:
#   12.09.2020
#
# COPYRIGHT (C):
#   2015-2020 - Patrick Neumann
#
# LICENSE:
#   This program is free software: you can redistribute it and/or modify
#   it under the terms of the GNU General Public License as published by
#   the Free Software Foundation, either version 3 of the License, or
#   (at your option) any later version.
#
# WARRANTY:
#   This program is distributed in the hope that it will be useful,
#   but WITHOUT ANY WARRANTY; without even the implied warranty of
#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#   GNU General Public License for more details.
#
#   You should have received a copy of the GNU General Public License
#   along with this program. If not, see <http://www.gnu.org/licenses/>.
#
# TODO:
#   ---
#
# HISTORY:
#   0.9 - Patrick Neumann - Initial (public) release
#
#===============================================================================

#-------------------------------------------------------------------------------
# Additional supported Distribution(s) (add before Library!).
#-------------------------------------------------------------------------------
SUPPORTED_OSR="arch"

#-------------------------------------------------------------------------------
# Check for library (casualscripter_nautilus-scripts_functions.sh).
#-------------------------------------------------------------------------------
readonly LIBRARY="${0%/*/*}/.casualscripter_nautilus-scripts_functions.sh"
if [ ! -f "${LIBRARY}" ] ; then
  zenity --error \
         --text \
         "ERROR: casualscripter_nautilus-scripts_functions.sh MISSING!"
  exit 1
fi

source "${LIBRARY}"

#-------------------------------------------------------------------------------
# Checks (see library "casualscripter_nautilus-scripts_functions.sh").
#-------------------------------------------------------------------------------
check_dep "${BASENAME_BIN}" "coreutils"
check_dep "${CURL_BIN}" "curl"
check_dep "${OPENSSL_BIN}" "openssl"

check_ext "${SOURCE}" "info|log|txt"

check_tmp

#-------------------------------------------------------------------------------
# Ask user for a response file if default is missing.
#-------------------------------------------------------------------------------
if [ -r "${SOURCE}.tsr" ] ; then
  readonly RESPONSE_FILE="${SOURCE}.tsr"
else
  readonly RESPONSE_FILE="$( ${ZENITY_BIN} --title="Select timestamp service response file (.tsr)" \
                                           --file-selection )"

  if [ -z "${RESPONSE_FILE}" ] ; then
    error_exit "no timestamp service response file (.tsr) choosen"
  fi
fi

#-------------------------------------------------------------------------------
# Generate freetsa verify file, if necessary.
#-------------------------------------------------------------------------------
readonly CACERTURL="http://freetsa.org/files/cacert.pem"
readonly PEMFILE="${DIRNAME}/freetsa-org-cacert.pem"
readonly FREETSAVERIFY="${TMP}/freetsa-verify-$( ${BASENAME_BIN} "${SOURCE}" ).txt"

if [ ! -f "${FREETSAVERIFY}" ] ; then
    ${PRINTF_BIN} "Verified log file:\n  %s\n\n" $( ${BASENAME_BIN} "${SOURCE}" ) > "${FREETSAVERIFY}"
    ${CURL_BIN} -o "${PEMFILE}" "${CACERTURL}"
    ${PRINTF_BIN} "URL to used certificate file of the Time Stamp Authority (freeTSA.org):\n  %s\n\n" "${CACERTURL}" >> "${FREETSAVERIFY}"
    ${PRINTF_BIN} "Used timestamp service response file (.tsr):\n  %s\n\n" "$( ${BASENAME_BIN} "${RESPONSE_FILE}" )" >> "${FREETSAVERIFY}"
    ${PRINTF_BIN} "Timestamp (date):\n  %s\n\n" "$( ${OPENSSL_BIN} ts -reply -in "${RESPONSE_FILE}" -text 2>/dev/null | ${SED_BIN} -n '/Time stamp:/ s/Time stamp: // p' )" >> "${FREETSAVERIFY}"
    ${PRINTF_BIN} "Output of 'openssl ts -verify' itself:\n  " >> "${FREETSAVERIFY}"
    ${OPENSSL_BIN} ts -verify -in "${RESPONSE_FILE}" -data "${SOURCE}" -CAfile "${PEMFILE}" 2>/dev/null >> "${FREETSAVERIFY}"
fi

#-------------------------------------------------------------------------------
# Display content of the resultfile "freetsa-verify...txt".
#-------------------------------------------------------------------------------
display_resultfile "${FREETSAVERIFY}"

exit 0