From 55c1cdbddef84ddbf1a2be1fed74a2d9246950fe Mon Sep 17 00:00:00 2001
From: Thibault Ayanides <thibault.ayanides@ovhcloud.com>
Date: Mon, 5 Oct 2020 17:05:47 +0200
Subject: [PATCH] 5.2.3_ssh_host_public_keys_perm_ownership

---
 .../5.2.3_ssh_public_keys_perm_ownership.sh   | 88 +++++++++++++++++++
 .../5.2.3_ssh_public_keys_perm_ownership.sh   | 10 +++
 2 files changed, 98 insertions(+)
 create mode 100755 bin/hardening/5.2.3_ssh_public_keys_perm_ownership.sh
 create mode 100755 tests/hardening/5.2.3_ssh_public_keys_perm_ownership.sh

diff --git a/bin/hardening/5.2.3_ssh_public_keys_perm_ownership.sh b/bin/hardening/5.2.3_ssh_public_keys_perm_ownership.sh
new file mode 100755
index 0000000..c068618
--- /dev/null
+++ b/bin/hardening/5.2.3_ssh_public_keys_perm_ownership.sh
@@ -0,0 +1,88 @@
+#!/bin/bash
+
+#
+# CIS Debian Hardening
+#
+
+#
+# 5.2.3 Ensure permissions on SSH public host key files are configured (Scored)
+#
+
+set -e # One error, it's over
+set -u # One variable unset, it's over
+
+HARDENING_LEVEL=1
+DESCRIPTION="Checking permissions and ownership to root 644 for ssh public keys. "
+
+DIR='/etc/ssh'
+PERMISSIONS='644'
+USER='root'
+GROUP='root'
+OPTIONS=(-xdev -type f -name "ssh_host_*_key.pub")
+
+# This function will be called if the script status is on enabled / audit mode
+audit () {
+    have_files_in_dir_correct_ownership $DIR $USER $GROUP OPTIONS
+    if [ $FNRET = 0 ]; then
+        ok "SSH public keys in $DIR have correct ownership"
+    else
+        crit "Some $DIR SSH public keys ownership were not set to $USER:$GROUP"
+    fi
+    have_files_in_dir_correct_permissions $DIR $PERMISSIONS OPTIONS
+    if [ $FNRET = 0 ]; then
+        ok "SSH public keys in $DIR have correct permissions"
+    else
+        crit "Some $DIR SSH public keys permissions were not set to $PERMISSIONS"
+    fi 
+}
+
+# This function will be called if the script status is on enabled mode
+apply () {
+
+    have_files_in_dir_correct_ownership $DIR $USER $GROUP OPTIONS
+    if [ $FNRET = 0 ]; then
+        ok "SSH public keys in $DIR have correct ownership"
+    else
+        warn "fixing $DIR SSH public keys ownership to $USER:$GROUP"
+        find /etc/ssh -xdev -type f -name 'ssh_host_*_key.pub' -exec chown root:root {} \;
+    fi
+    have_files_in_dir_correct_permissions $DIR $PERMISSIONS OPTIONS
+    if [ $FNRET = 0 ]; then
+        ok "SSH public keys in $DIR have correct permissions"
+    else
+        info "fixing $DIR SSH public keys permissions to $PERMISSIONS"
+        find /etc/ssh -xdev -type f -name 'ssh_host_*_key.pub' -exec chmod 0644 {} \;
+    fi
+}
+
+# This function will check config parameters required
+check_config() {
+    does_user_exist $USER
+    if [ $FNRET != 0 ]; then
+        crit "$USER does not exist"
+        exit 128
+    fi
+    does_group_exist $GROUP
+    if [ $FNRET != 0 ]; then
+        crit "$GROUP does not exist"
+        exit 128
+    fi
+}
+
+# Source Root Dir Parameter
+if [ -r /etc/default/cis-hardening ]; then
+    . /etc/default/cis-hardening
+fi
+if [ -z "$CIS_ROOT_DIR" ]; then
+     echo "There is no /etc/default/cis-hardening file nor cis-hardening directory in current environment."
+     echo "Cannot source CIS_ROOT_DIR variable, aborting."
+    exit 128
+fi
+
+# Main function, will call the proper functions given the configuration (audit, enabled, disabled)
+if [ -r $CIS_ROOT_DIR/lib/main.sh ]; then
+    . $CIS_ROOT_DIR/lib/main.sh
+else
+    echo "Cannot find main.sh, have you correctly defined your root directory? Current value is $CIS_ROOT_DIR in /etc/default/cis-hardening"
+    exit 128
+fi
diff --git a/tests/hardening/5.2.3_ssh_public_keys_perm_ownership.sh b/tests/hardening/5.2.3_ssh_public_keys_perm_ownership.sh
new file mode 100755
index 0000000..b333419
--- /dev/null
+++ b/tests/hardening/5.2.3_ssh_public_keys_perm_ownership.sh
@@ -0,0 +1,10 @@
+# run-shellcheck
+test_audit() {
+    describe Running on blank host
+    register_test retvalshouldbe 0
+    dismiss_count_for_test
+    # shellcheck disable=2154
+    run blank /opt/debian-cis/bin/hardening/"${script}".sh --audit-all
+
+    # TODO fill comprehensive tests
+}