xref: /freebsd/libexec/save-entropy/save-entropy.sh (revision 10fe5181ec081554fdfb3c63dec05c6deaf7b72c)
127a803d6SDoug Barton#!/bin/sh
227a803d6SDoug Barton#
327a803d6SDoug Barton# Copyright (c) 2001  The FreeBSD Project
427a803d6SDoug Barton# All rights reserved.
527a803d6SDoug Barton#
627a803d6SDoug Barton# Redistribution and use in source and binary forms, with or without
727a803d6SDoug Barton# modification, are permitted provided that the following conditions
827a803d6SDoug Barton# are met:
927a803d6SDoug Barton# 1. Redistributions of source code must retain the above copyright
1027a803d6SDoug Barton#    notice, this list of conditions and the following disclaimer.
1127a803d6SDoug Barton# 2. Redistributions in binary form must reproduce the above copyright
1227a803d6SDoug Barton#    notice, this list of conditions and the following disclaimer in the
1327a803d6SDoug Barton#    documentation and/or other materials provided with the distribution.
1427a803d6SDoug Barton#
1527a803d6SDoug Barton# THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
1627a803d6SDoug Barton# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
1727a803d6SDoug Barton# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
1827a803d6SDoug Barton# ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
1927a803d6SDoug Barton# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
2027a803d6SDoug Barton# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
2127a803d6SDoug Barton# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
2227a803d6SDoug Barton# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
2327a803d6SDoug Barton# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
2427a803d6SDoug Barton# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
2527a803d6SDoug Barton# SUCH DAMAGE.
2627a803d6SDoug Barton#
2727a803d6SDoug Barton# $FreeBSD$
2827a803d6SDoug Barton
2927a803d6SDoug Barton# This script is called by cron to store bits of randomness which are
3027a803d6SDoug Barton# then used to seed /dev/random on boot.
3127a803d6SDoug Barton
3210fe5181SDoug Barton# Originally developed by Doug Barton, DougB@FreeBSD.org
3310fe5181SDoug Barton
3427a803d6SDoug BartonPATH=/bin:/usr/bin
3527a803d6SDoug Barton
3627a803d6SDoug Barton# If there is a global system configuration file, suck it in.
3727a803d6SDoug Barton#
3827a803d6SDoug Bartonif [ -r /etc/defaults/rc.conf ]; then
3927a803d6SDoug Barton	. /etc/defaults/rc.conf
4027a803d6SDoug Barton	source_rc_confs
4127a803d6SDoug Bartonelif [ -r /etc/rc.conf ]; then
4227a803d6SDoug Barton	. /etc/rc.conf
4327a803d6SDoug Bartonfi
4427a803d6SDoug Barton
4527a803d6SDoug Bartoncase ${entropy_dir} in
4627a803d6SDoug Barton[Nn][Oo])
4727a803d6SDoug Barton	exit 0
4827a803d6SDoug Barton	;;
4927a803d6SDoug Barton*)
5010fe5181SDoug Barton	entropy_dir=${entropy_dir:-/var/db/entropy}
5127a803d6SDoug Barton	;;
5227a803d6SDoug Bartonesac
5327a803d6SDoug Barton
5427a803d6SDoug Bartonentropy_save_sz=${entropy_save_sz:-2048}
5527a803d6SDoug Bartonentropy_save_num=${entropy_save_num:-8}
5627a803d6SDoug Barton
5727a803d6SDoug Bartonif [ ! -d "${entropy_dir}" ]; then
5827a803d6SDoug Barton	umask 077
5927a803d6SDoug Barton	mkdir "${entropy_dir}" || {
6010fe5181SDoug Barton	    logger -is -t "$0" The entropy directory "${entropy_dir}" does not \
6127a803d6SDoug Bartonexist, and cannot be created.  Therefore no entropy can be saved. ;
6227a803d6SDoug Barton	    exit 1;}
6327a803d6SDoug Barton	/usr/sbin/chown operator:operator "${entropy_dir}"
6427a803d6SDoug Barton	chmod 0700 "${entropy_dir}"
6527a803d6SDoug Bartonfi
6627a803d6SDoug Barton
6727a803d6SDoug Bartonumask 377
6827a803d6SDoug Barton
6910fe5181SDoug Bartonfor file_num in `jot ${entropy_save_num} ${entropy_save_num} 1`; do
7010fe5181SDoug Barton	if [ -e "${entropy_dir}/saved-entropy.${file_num}" ]; then
7127a803d6SDoug Barton		if [ -f "${entropy_dir}/saved-entropy.${file_num}" ]; then
7227a803d6SDoug Barton			new_num=$(($file_num + 1))
7310fe5181SDoug Barton			if [ "${new_num}" -gt "${entropy_save_num}" ]; then
7410fe5181SDoug Barton				rm -f "${entropy_dir}/saved-entropy.${file_num}"
7510fe5181SDoug Barton			else
7627a803d6SDoug Barton				mv "${entropy_dir}/saved-entropy.${file_num}" \
7727a803d6SDoug Barton				    "${entropy_dir}/saved-entropy.${new_num}"
7827a803d6SDoug Barton			fi
7910fe5181SDoug Barton		else
8010fe5181SDoug Barton			logger -is -t "$0" \
8110fe5181SDoug Barton"${entropy_dir}/saved-entropy.${file_num} is not a regular file, and therefore \
8210fe5181SDoug Bartonit will not be rotated. Entropy file harvesting is aborted."
8310fe5181SDoug Barton			exit 1
8410fe5181SDoug Barton		fi
8510fe5181SDoug Barton	fi
8627a803d6SDoug Bartondone
8727a803d6SDoug Barton
8827a803d6SDoug Bartondd if=/dev/random of="${entropy_dir}/saved-entropy.1" \
8927a803d6SDoug Barton    bs=2048 count=1 2> /dev/null
9027a803d6SDoug Barton
9127a803d6SDoug Bartonexit 0
9227a803d6SDoug Barton
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