#!/bin/bash
# SPDX-Version: 3.0
# SPDX-CreationInfo: 2025-06-17; WEIDNER, Marc S.; <msw@coresecret.dev>
# SPDX-ExternalRef: GIT https://git.coresecret.dev/msw/CISS.debian.installer.git
# SPDX-FileContributor: WEIDNER, Marc S.; Centurion Intelligence Consulting Agency
# SPDX-FileCopyrightText: 2024-2025; WEIDNER, Marc S.; <msw@coresecret.dev>
# SPDX-FileType: SOURCE
# SPDX-License-Identifier: EUPL-1.2 OR LicenseRef-CCLA-1.0
# SPDX-LicenseComment: This file is part of the CISS.debian.installer.secure framework.
# SPDX-PackageName: CISS.debian.installer
# SPDX-Security-Contact: security@coresecret.eu

guard_sourcing

#######################################
# Hardening '/etc/logrotate'.
# Globals:
#   RECOVERY
#   TARGET
#   VAR_RUN_RECOVERY
# Arguments:
#   None
# Returns:
#   0: on success
#######################################
hardening_logrotate() {
  ### Declare Arrays, HashMaps, and Variables.
  declare     var_target="${TARGET}"

  ### Check for TARGET / RECOVERY.
  [[ "${VAR_RUN_RECOVERY}" == "true" ]] && var_target="${RECOVERY}"

  rm -f           "${var_target}/etc/logrotate.conf"
  insert_header   "${var_target}/etc/logrotate.conf"
  insert_comments "${var_target}/etc/logrotate.conf"
  cat << EOF >>   "${var_target}/etc/logrotate.conf"
# See "man logrotate" for details. Global options do not affect preceding include directives.

# Rotate log files daily
daily

# Keep 384 daily worth of backlogs.
rotate 384

# Hard cap: delete rotated logs older than 384 days.
maxage 384

# Do not rotate the log if it is empty (this overrides the ifempty option).
notifempty

# Create new (empty) log files after rotating old ones.
create

# Use date as a suffix of the rotated file.
dateext

# Use yesterday's instead of today's date to create the dateext extension, so that the rotated log file has a date in its name
# that is the same as the timestamps within it.
dateyesterday

# Enable compression
compress

# Use zstd instead of gzip.
compresscmd /usr/bin/zstd

# File extension for compressed logs.
compressext .zst

# Set zstd level 3 (default).
compressoptions -20

# How to decompress for 'logrotate -d' or similar.
uncompresscmd /usr/bin/unzstd

# Keep the most recent rotation uncompressed for one cycle.
delaycompress

# Delete log files using shred -u instead of unlink().
shred

# packages drop log rotation information into this directory
include /etc/logrotate.d

# system-specific logs may also be configured here.

# vim: number et ts=2 sw=2 sts=2 ai tw=128 ft=conf
EOF

  guard_dir && return 0
}
### Prevents accidental 'unset -f'.
# shellcheck disable=SC2034
readonly -f hardening_logrotate
# vim: number et ts=2 sw=2 sts=2 ai tw=128 ft=sh