#!/usr/bin/env bash

# Copyright 2015 Martin Preisler <martin@preisler.me> 
#
# This library is free software; you can redistribute it and/or
# modify it under the terms of the GNU Lesser General Public
# License as published by the Free Software Foundation; either
# version 2 of the License, or (at your option) any later version.
#
# This library 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
# Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public
# License along with this library; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

function die()
{
    echo "$*" >&2
    exit 1
}

function invalid()
{
    echo -e "$*\n" >&2
    usage
    exit 1
}

function usage()
{
    echo "oscap-ssh -- Tool for running oscap over SSH and collecting results."
    echo
    echo "Usage:"
    echo
    echo "$ oscap-ssh user@host 22 info INPUT_CONTENT"
    echo "$ oscap-ssh user@host 22 xccdf eval [options] INPUT_CONTENT"
    echo
    echo "Only source datastreams are supported as INPUT_CONTENT!"
    echo
    echo "supported oscap xccdf eval options are:"
    echo "  --profile"
    echo "  --tailoring-file"
    echo "  --tailoring-id"
    echo "  --cpe (external OVAL dependencies are not supported yet!)"
    # --check-engine-results is not supported
    # use --results-arf instead
    echo "  --oval-results"
    echo "  --results"
    echo "  --results-arf"
    echo "  --report"
    echo "  --skip-valid"
    echo "  --fetch-remote-resources"
    echo "  --progress"
    echo "  --datastream-id"
    echo "  --xccdf-id"
    echo "  --benchmark-id"
    echo "  --remediate"
    echo
    echo "$ oscap-ssh user@host 22 oval eval [options] INPUT_CONTENT"
    echo
    echo "supported oscap oval eval options are:"
    echo "  --id"
    echo "  --variables"
    echo "  --directives"
    echo "  --results"
    echo "  --report"
    echo "  --skip-valid"
    echo "  --datastream-id"
    echo "  --oval-id"
    echo
    echo "$ oscap-ssh user@host 22 oval collect [options] INPUT_CONTENT"
    echo
    echo "supported oscap oval collect options are:"
    echo "  --id"
    echo "  --syschar"
    echo "  --variables"
    echo "  --skip-valid"
    echo
    echo "specific option for oscap-ssh (must be first argument):"
    echo "  --sudo"
    echo
    echo "To supply additional options to ssh/scp, define the SSH_ADDITIONAL_OPTIONS variable"
    echo "For instance, to ignore known hosts records, define SSH_ADDITIONAL_OPTIONS='-o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null'"
    echo
    echo "specific option for oscap-ssh (must be first argument):"
    echo
    echo "See \`man oscap\` to learn more about semantics of these options."
}

# $1, $2, ... SSH options (pass them as separate arguments)
function ssh_execute_with_options {
    ssh -o ControlPath="$MASTER_SOCKET" $SSH_ADDITIONAL_OPTIONS "$@" -p "$SSH_PORT" "$SSH_HOST"
}

# $1: The SSH command.
# $2: More of additional options (optional, pass one space-separated string)
function ssh_execute_with_command_and_options {
    ssh -o ControlPath="$MASTER_SOCKET" $SSH_ADDITIONAL_OPTIONS $2 -p "$SSH_PORT" "$SSH_HOST" "$1"
}

# $1: Local filename to copy
# $2: Remote destination
function scp_copy_to_temp_dir {
    scp -o ControlPath="$MASTER_SOCKET" -P "$SSH_PORT" $SSH_ADDITIONAL_OPTIONS "$1" "$SSH_HOST:$REMOTE_TEMP_DIR/$2"
}

# $1: Remote filename to get
# $2: Local destination
function scp_retreive_from_temp_dir {
    scp -o ControlPath="$MASTER_SOCKET" -P "$SSH_PORT" $SSH_ADDITIONAL_OPTIONS "$SSH_HOST:$REMOTE_TEMP_DIR/$1" "$2"
}

# $1: The name of the array holding command elements
# Returns: String, where individual command components are double-quoted, so they are not interpreted by the shell.
#  For example, an array ('-p' '(all)') will be transformed to "\"-p\" \"(all)\"", so after the shell expansion, it will end up as "-p" "(all)".
function command_array_to_string {
    eval "printf '\"%s\" ' \"\${$1[@]}\""
}

function first_argument_is_sudo {
    [ "$1" == "sudo" ] || [ "$1" == "--sudo" ]
    return $?
}

function sanity_check_arguments {
    if [ $# -lt 1 ]; then
        invalid "No arguments provided."
    elif [ "$1" == "-h" ] || [ "$1" == "--help" ]; then
        usage
        exit 0
    elif first_argument_is_sudo "$@"; then
        OSCAP_SUDO="sudo"
        # force pseudo-tty allocation so that users can type their password if necessary
        SSH_TTY_ALLOCATION_OPTION="-t"
        shift
    fi
    if [ $# -lt 2 ]; then
        invalid "Missing ssh host and ssh port."
    fi
}

function check_oscap_arguments {
    if [ "$1" == "--v" ] || [ "$1" == "--version" ]; then
        true
    elif [ "$1" == "-h" ] || [ "$1" == "--help" ]; then
        true
    elif [ "$1" == "info" ]; then
        true
    elif [ "$1 $2" == "xccdf eval" ]; then
        true
    elif [ "$1 $2" == "oval eval" ]; then
        true
    elif [ "$1 $2" == "oval collect" ]; then
        true
    else
        die "This script only supports 'sudo' as first argument, '-h', '--help', '--v', '--version', 'info', 'xccdf eval', 'oval eval' and 'oval collect'."
    fi
}


hash ssh 2> /dev/null || die "Cannot find ssh, please install the OpenSSH client."
hash scp 2> /dev/null || die "Cannot find scp, please install the OpenSSH client."
hash mktemp 2> /dev/null || die "Cannot find mktemp, please install coreutils."


OSCAP_SUDO=""
# SSH_ADDITIONAL_OPTIONS may be defined in the calling shell
SSH_TTY_ALLOCATION_OPTION=""

sanity_check_arguments "$@"
first_argument_is_sudo "$@" && shift

SSH_HOST="$1"
SSH_PORT="$2"

shift 2

check_oscap_arguments "$@"

MASTER_SOCKET_DIR=$(mktemp -d)
MASTER_SOCKET="$MASTER_SOCKET_DIR/ssh_socket"

echo "Connecting to '$SSH_HOST' on port '$SSH_PORT'..."
ssh_execute_with_options -M -f -N -o ServerAliveInterval=60 || die "Failed to connect!"
echo "Connected!"

REMOTE_TEMP_DIR=$(ssh_execute_with_command_and_options "mktemp -d") || die "Failed to create remote temporary directory!"

oscap_args=("$@")

LOCAL_CONTENT_PATH=""
LOCAL_TAILORING_PATH=""
LOCAL_CPE_PATH=""
LOCAL_VARIABLES_PATH=""
LOCAL_DIRECTIVES_PATH=""
TARGET_RESULTS=""
TARGET_RESULTS_ARF=""
TARGET_REPORT=""
TARGET_SYSCHAR=""
OVAL_RESULTS=""

# We have to rewrite various paths to a remote temp dir
for i in $(seq 0 `expr $# - 1`); do
    let j=i+1

    case "${oscap_args[i]}" in
    ("--tailoring-file")
        LOCAL_TAILORING_PATH=${oscap_args[j]}
        oscap_args[j]="$REMOTE_TEMP_DIR/tailoring.xml"
      ;;
    ("--cpe")
        LOCAL_CPE_PATH=${oscap_args[j]}
        oscap_args[j]="$REMOTE_TEMP_DIR/cpe.xml"
      ;;
    ("--variables")
        LOCAL_VARIABLES_PATH=${oscap_args[j]}
        oscap_args[j]="$REMOTE_TEMP_DIR/variables.xml"
      ;;
    ("--directives")
        LOCAL_DIRECTIVES_PATH=${oscap_args[j]}
        oscap_args[j]="$REMOTE_TEMP_DIR/directives.xml"
      ;;
    ("--results")
        TARGET_RESULTS=${oscap_args[j]}
        oscap_args[j]="$REMOTE_TEMP_DIR/results.xml"
      ;;
    ("--results-arf")
        TARGET_RESULTS_ARF=${oscap_args[j]}
        oscap_args[j]="$REMOTE_TEMP_DIR/results-arf.xml"
      ;;
    ("--report")
        TARGET_REPORT=${oscap_args[j]}
        oscap_args[j]="$REMOTE_TEMP_DIR/report.html"
      ;;
    ("--syschar")
        TARGET_SYSCHAR=${oscap_args[j]}
        oscap_args[j]="$REMOTE_TEMP_DIR/syschar.xml"
      ;;
    ("--oval-results")
        OVAL_RESULTS="yes"
      ;;
    *)
      ;;
    esac
done

if [ "$1" != "--v" ] && [ "$1" != "--version" ] && [ "$1" != "-h" ] && [ "$1" != "--help" ]; then
    # Last argument should be the content path
    LOCAL_CONTENT_PATH="${oscap_args[`expr $# - 1`]}"
    oscap_args[`expr $# - 1`]="$REMOTE_TEMP_DIR/input.xml"
fi

[ "$LOCAL_CONTENT_PATH" == "" ] || [ -f "$LOCAL_CONTENT_PATH" ] || die "Expected the last argument to be an input file, '$LOCAL_CONTENT_PATH' isn't a valid file path or the file doesn't exist!"
[ "$LOCAL_TAILORING_PATH" == "" ] || [ -f "$LOCAL_TAILORING_PATH" ] || die "Tailoring file path '$LOCAL_TAILORING_PATH' isn't a valid file path or the file doesn't exist!"
[ "$LOCAL_CPE_PATH" == "" ] || [ -f "$LOCAL_CPE_PATH" ] || die "CPE file path '$LOCAL_CPE_PATH' isn't a valid file path or the file doesn't exist!"
[ "$LOCAL_VARIABLES_PATH" == "" ] || [ -f "$LOCAL_VARIABLES_PATH" ] || die "OVAL variables file path '$LOCAL_VARIABLES_PATH' isn't a valid file path or the file doesn't exist!"
[ "$LOCAL_DIRECTIVES_PATH" == "" ] || [ -f "$LOCAL_DIRECTIVES_PATH" ] || die "OVAL directives file path '$LOCAL_DIRECTIVES_PATH' isn't a valid file path or the file doesn't exist!"

if [ "$LOCAL_CONTENT_PATH" != "" ]; then
    echo "Copying input file '$LOCAL_CONTENT_PATH' to remote working directory '$REMOTE_TEMP_DIR'..."
    scp_copy_to_temp_dir "$LOCAL_CONTENT_PATH" input.xml || die "Failed to copy input file to remote temporary directory!"
fi
if [ "$LOCAL_TAILORING_PATH" != "" ]; then
    echo "Copying tailoring file '$LOCAL_TAILORING_PATH' to remote working directory '$REMOTE_TEMP_DIR'..."
    scp_copy_to_temp_dir "$LOCAL_TAILORING_PATH" tailoring.xml || die "Failed to copy tailoring file to remote temporary directory!"
fi
if [ "$LOCAL_CPE_PATH" != "" ]; then
    echo "Copying CPE file '$LOCAL_CPE_PATH' to remote working directory '$REMOTE_TEMP_DIR'..."
    scp_copy_to_temp_dir "$LOCAL_CPE_PATH" cpe.xml || die "Failed to copy CPE file to remote temporary directory!"
fi
if [ "$LOCAL_VARIABLES_PATH" != "" ]; then
    echo "Copying OVAL variables file '$LOCAL_VARIABLES_PATH' to remote working directory '$REMOTE_TEMP_DIR'..."
    scp_copy_to_temp_dir "$LOCAL_VARIABLES_PATH" variables.xml || die "Failed to copy OVAL variables file to remote temporary directory!"
fi
if [ "$LOCAL_DIRECTIVES_PATH" != "" ]; then
    echo "Copying OVAL directives file '$LOCAL_DIRECTIVES_PATH' to remote working directory '$REMOTE_TEMP_DIR'..."
    scp_copy_to_temp_dir "$LOCAL_DIRECTIVES_PATH" directives.xml || die "Failed to copy OVAL directives file to remote temporary directory!"
fi

echo "Starting the evaluation..."
# changing directory because of --oval-results support. oval results files are
# dumped into PWD, and we can't be sure by the file names - we need controlled
# environment
if [ -z "$OSCAP_SUDO" ]; then
    ssh_execute_with_command_and_options "cd $REMOTE_TEMP_DIR; oscap $(command_array_to_string oscap_args)" "$SSH_TTY_ALLOCATION_OPTION"
else
    OSCAP_CMD="oscap $(command_array_to_string oscap_args); rc=\$?; chown \$SUDO_USER $REMOTE_TEMP_DIR/*; exit \$rc"
    ssh_execute_with_command_and_options "cd $REMOTE_TEMP_DIR; $OSCAP_SUDO sh -c '$OSCAP_CMD'" "$SSH_TTY_ALLOCATION_OPTION"
fi
OSCAP_EXIT_CODE=$?
echo "oscap exit code: $OSCAP_EXIT_CODE"

echo "Copying back requested files..."
if [ "$TARGET_RESULTS" != "" ]; then
    scp_retreive_from_temp_dir results.xml "$TARGET_RESULTS" || die "Failed to copy the results file back to local machine!"
fi
if [ "$TARGET_RESULTS_ARF" != "" ]; then
    scp_retreive_from_temp_dir results-arf.xml "$TARGET_RESULTS_ARF" || die "Failed to copy the ARF file back to local machine!"
fi
if [ "$TARGET_REPORT" != "" ]; then
    scp_retreive_from_temp_dir report.html "$TARGET_REPORT" || die "Failed to copy the HTML report back to local machine!"
fi
if [ "$TARGET_SYSCHAR" != "" ]; then
    scp_retreive_from_temp_dir syschar.xml "$TARGET_SYSCHAR" || die "Failed to copy the OVAL syschar file back to local machine!"
fi
if [ "$OVAL_RESULTS" == "yes" ]; then
    scp_retreive_from_temp_dir '*.result.xml' "./" || die "Failed to copy OVAL result files back to local machine!"
fi

echo "Removing remote temporary directory..."
ssh_execute_with_command_and_options "rm -r $REMOTE_TEMP_DIR" || die "Failed to remove remote temporary directory!"
echo "Disconnecting ssh and removing master ssh socket directory..."
ssh_execute_with_options -O exit || die "Failed to disconnect!"
rm -r "$MASTER_SOCKET_DIR" || die "Failed to remove local master SSH socket directory!"

exit $OSCAP_EXIT_CODE