V8.13.384.2025.11.06

Signed-off-by: Marc S. Weidner <msw@coresecret.dev>

lib/lib_hardening_ssh_tcp.sh

@@ -0,0 +1,100 @@
+#!/bin/bash
+# SPDX-Version: 3.0
+# SPDX-CreationInfo: 2025-05-05; WEIDNER, Marc S.; <msw@coresecret.dev>
+# SPDX-ExternalRef: GIT https://git.coresecret.dev/msw/CISS.debian.live.builder.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.live.builder
+# SPDX-Security-Contact: security@coresecret.eu
+
+guard_sourcing
+
+#######################################
+# SSH hardening via TCP wrapper.
+# Globals:
+#   ARY_HANDLER_JUMPHOST
+#   BASH_SOURCE
+#   VAR_WORKDIR
+# Arguments:
+#   None
+# Returns:
+#   0: on success
+#######################################
+hardening_ssh_tcp() {
+  printf "\e[95m++++ ++++ ++++ ++++ ++++ ++++ ++ 🧪 %s starting ... \e[0m\n" "${BASH_SOURCE[0]}"
+
+  if ((${#ARY_HANDLER_JUMPHOST[@]} > 0)); then
+    declare allowed=""
+    cat << 'EOF' >| "${VAR_WORKDIR}/hosts.allow"
+# SPDX-Version: 3.0
+# SPDX-CreationInfo: 2025-05-05; WEIDNER, Marc S.; <msw@coresecret.dev>
+# SPDX-ExternalRef: GIT https://git.coresecret.dev/msw/CISS.debian.live.builder.git
+# SPDX-FileContributor: WEIDNER, Marc S.; Centurion Intelligence Consulting Agency
+# SPDX-FileCopyrightText: 2024-2025; WEIDNER, Marc S.; <msw@coresecret.dev>
+# SPDX-FileType: SOURCE
+# SPDX-License-Identifier: EUPL-1.2 OR LicenseRef-CCLA-1.0
+# SPDX-LicenseComment: This file is part of the CISS.debian.installer.secure framework.
+# SPDX-PackageName: CISS.debian.live.builder
+# SPDX-Security-Contact: security@coresecret.eu
+
+# /etc/hosts.allow: list of hosts that are allowed to access the system.
+#                   See the manual pages hosts_access(5) and hosts_options(5).
+#
+# Example:    ALL: LOCAL @some_netgroup
+#             ALL: .foobar.edu EXCEPT terminalserver.foobar.edu
+#
+# If you're going to protect the portmapper use the name "rpcbind" for the
+# daemon name. See rpcbind(8) and rpc.mountd(8) for further information.
+#
+
+EOF
+
+    allowed=$(echo "${ARY_HANDLER_JUMPHOST[*]}" | tr '\n' ' ')
+    printf 'sshd: %s\n\n# vim: number et ts=2 sw=2 sts=2 ai tw=128 ft=conf\n' "${allowed}" >> "${VAR_WORKDIR}/hosts.allow"
+
+    cat << 'EOF' >| "${VAR_WORKDIR}/hosts.deny"
+# SPDX-Version: 3.0
+# SPDX-CreationInfo: 2025-05-05; WEIDNER, Marc S.; <msw@coresecret.dev>
+# SPDX-ExternalRef: GIT https://git.coresecret.dev/msw/CISS.debian.live.builder.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.live.builder
+# SPDX-Security-Contact: security@coresecret.eu
+
+# /etc/hosts.deny: list of hosts that are _not_ allowed to access the system.
+#                  See the manual pages hosts_access(5) and hosts_options(5).
+#
+# Example:    ALL: some.host.name, .some.domain
+#             ALL EXCEPT in.fingerd: other.host.name, .other.domain
+#
+# If you're going to protect the portmapper use the name "rpcbind" for the
+# daemon name. See rpcbind(8) and rpc.mountd(8) for further information.
+#
+# The PARANOID wildcard matches any host whose name does not match its
+# address.
+#
+# You may wish to enable this to ensure any programs that don't
+# validate looked-up hostnames still leave understandable logs. In past
+# versions of Debian, this has been the default.
+# ALL: PARANOID
+
+ALL: ALL
+
+# vim: number et ts=2 sw=2 sts=2 ai tw=128 ft=conf
+EOF
+  fi
+
+  printf "\e[92m++++ ++++ ++++ ++++ ++++ ++++ ++ ✅ %s successfully applied. \e[0m\n" "${BASH_SOURCE[0]}"
+
+  return 0
+}
+### Prevents accidental 'unset -f'.
+# shellcheck disable=SC2034
+readonly -f hardening_ssh_tcp
+# vim: number et ts=2 sw=2 sts=2 ai tw=128 ft=sh