1#!/bin/sh 2# 3# SPDX-License-Identifier: BSD-2-Clause-FreeBSD 4# 5# Copyright (c) 2001-2006,2012 Douglas Barton, dougb@FreeBSD.org 6# All rights reserved. 7# 8# Redistribution and use in source and binary forms, with or without 9# modification, are permitted provided that the following conditions 10# are met: 11# 1. Redistributions of source code must retain the above copyright 12# notice, this list of conditions and the following disclaimer. 13# 2. Redistributions in binary form must reproduce the above copyright 14# notice, this list of conditions and the following disclaimer in the 15# documentation and/or other materials provided with the distribution. 16# 17# THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 18# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20# ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 21# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27# SUCH DAMAGE. 28# 29# $FreeBSD$ 30 31# This script is called by cron to store bits of randomness which are 32# then used to seed /dev/random on boot. 33 34# Originally developed by Doug Barton, dougb@FreeBSD.org 35 36PATH=/bin:/usr/bin 37 38# If there is a global system configuration file, suck it in. 39# 40if [ -r /etc/defaults/rc.conf ]; then 41 . /etc/defaults/rc.conf 42 source_rc_confs 2>/dev/null 43elif [ -r /etc/rc.conf ]; then 44 . /etc/rc.conf 2>/dev/null 45fi 46 47[ $(/sbin/sysctl -n security.jail.jailed) = 0 ] || exit 0 48 49case ${entropy_dir} in 50[Nn][Oo]) 51 exit 0 52 ;; 53*) 54 entropy_dir=${entropy_dir:-/var/db/entropy} 55 ;; 56esac 57 58entropy_save_sz=${entropy_save_sz:-4096} 59entropy_save_num=${entropy_save_num:-8} 60 61if [ ! -d "${entropy_dir}" ]; then 62 install -d -o operator -g operator -m 0700 "${entropy_dir}" || { 63 logger -is -t "$0" The entropy directory "${entropy_dir}" does \ 64 not exist, and cannot be created. Therefore no entropy can \ 65 be saved.; exit 1; } 66fi 67 68cd "${entropy_dir}" || { 69 logger -is -t "$0" Cannot cd to the entropy directory: "${entropy_dir}". \ 70 Entropy file rotation is aborted.; exit 1; } 71 72for f in saved-entropy.*; do 73 case "${f}" in saved-entropy.\*) continue ;; esac # No files match 74 [ ${f#saved-entropy\.} -gt ${entropy_save_num} ] && unlink ${f} 75done 76 77umask 177 78 79# Scan slots [1..$entropy_save_num), picking an empty slot or the oldest 80# existing file if no empty slot was available. 81# 82# 1. Find out the first regular file or empty slot (and its serial number) 83# 84n=1 85while [ ${n} -le ${entropy_save_num} ]; do 86 save_file="saved-entropy.${n}" 87 if [ ! -e "${save_file}" -o -f "${save_file}" ]; then 88 break 89 else 90 logger -is -t "$0" \ 91 "${save_file}" is not a regular file, skipped. 92 fi 93 n=$(( ${n} + 1 )) 94done 95# 96# 2. Start from (serial number + 1), and check if the slot is empty 97# or is an older regular file, update save_file pointer in either 98# case, and break early if we found an empty slot. 99# 100if [ -f ${save_file} ]; then 101 n=$(( ${n} + 1 )) 102 while [ ${n} -le ${entropy_save_num} ]; do 103 next_file=saved-entropy.${n} 104 if [ -f "${next_file}" ]; then 105 [ "${next_file}" -ot "${save_file}" ] && \ 106 save_file="${next_file}" 107 elif [ ! -e "${next_file}" ]; then 108 save_file="${next_file}" 109 break 110 else 111 logger -is -t "$0" \ 112 "${next_file}" is not a regular file, skipped. 113 fi 114 n=$(( ${n} + 1 )) 115 done 116fi 117# 118# 3. Check if the pointer we have in hand is really a regular file or 119# an empty slot, and bail out as that means there is no available slot. 120# 121if [ -e "${save_file}" -a ! -f "${save_file}" ]; then 122 logger -is -t "$0" \ 123 No available slot in "${entropy_dir}", save entropy is aborted. 124 exit 1 125fi 126 127# Save entropy to the selected slot. 128chmod 600 "${save_file}" 2>/dev/null || : 129dd if=/dev/random of="${save_file}" bs=${entropy_save_sz} count=1 2>/dev/null 130chflags nodump "${save_file}" 2>/dev/null || : 131fsync "${save_file}" "." 132 133exit 0 134