1#!/bin/sh 2# 3# Copyright (c) 2001-2006,2012 Douglas Barton, dougb@FreeBSD.org 4# All rights reserved. 5# 6# Redistribution and use in source and binary forms, with or without 7# modification, are permitted provided that the following conditions 8# are met: 9# 1. Redistributions of source code must retain the above copyright 10# notice, this list of conditions and the following disclaimer. 11# 2. Redistributions in binary form must reproduce the above copyright 12# notice, this list of conditions and the following disclaimer in the 13# documentation and/or other materials provided with the distribution. 14# 15# THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 16# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 17# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 18# ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 19# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 20# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 21# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25# SUCH DAMAGE. 26# 27# $FreeBSD: stable/11/libexec/save-entropy/save-entropy.sh 355749 2019-12-14 09:54:30Z delphij $ 28 29# This script is called by cron to store bits of randomness which are 30# then used to seed /dev/random on boot. 31 32# Originally developed by Doug Barton, dougb@FreeBSD.org 33 34PATH=/bin:/usr/bin 35 36# If there is a global system configuration file, suck it in. 37# 38if [ -r /etc/defaults/rc.conf ]; then 39 . /etc/defaults/rc.conf 40 source_rc_confs 2>/dev/null 41elif [ -r /etc/rc.conf ]; then 42 . /etc/rc.conf 2>/dev/null 43fi 44 45[ $(/sbin/sysctl -n security.jail.jailed) = 0 ] || exit 0 46 47case ${entropy_dir} in 48[Nn][Oo]) 49 exit 0 50 ;; 51*) 52 entropy_dir=${entropy_dir:-/var/db/entropy} 53 ;; 54esac 55 56entropy_save_sz=${entropy_save_sz:-4096} 57entropy_save_num=${entropy_save_num:-8} 58 59if [ ! -d "${entropy_dir}" ]; then 60 install -d -o operator -g operator -m 0700 "${entropy_dir}" || { 61 logger -is -t "$0" The entropy directory "${entropy_dir}" does \ 62 not exist, and cannot be created. Therefore no entropy can \ 63 be saved.; exit 1; } 64fi 65 66cd "${entropy_dir}" || { 67 logger -is -t "$0" Cannot cd to the entropy directory: "${entropy_dir}". \ 68 Entropy file rotation is aborted.; exit 1; } 69 70for f in saved-entropy.*; do 71 case "${f}" in saved-entropy.\*) continue ;; esac # No files match 72 [ ${f#saved-entropy\.} -gt ${entropy_save_num} ] && unlink ${f} 73done 74 75umask 177 76 77# Scan slots [1..$entropy_save_num), picking an empty slot or the oldest 78# existing file if no empty slot was available. 79# 80# 1. Find out the first regular file or empty slot (and its serial number) 81# 82n=1 83while [ ${n} -le ${entropy_save_num} ]; do 84 save_file="saved-entropy.${n}" 85 if [ ! -e "${save_file}" -o -f "${save_file}" ]; then 86 break 87 else 88 logger -is -t "$0" \ 89 "${save_file}" is not a regular file, skipped. 90 fi 91 n=$(( ${n} + 1 )) 92done 93# 94# 2. Start from (serial number + 1), and check if the slot is empty 95# or is an older regular file, update save_file pointer in either 96# case, and break early if we found an empty slot. 97# 98if [ -f ${save_file} ]; then 99 n=$(( ${n} + 1 )) 100 while [ ${n} -le ${entropy_save_num} ]; do 101 next_file=saved-entropy.${n} 102 if [ -f "${next_file}" ]; then 103 [ "${next_file}" -ot "${save_file}" ] && \ 104 save_file="${next_file}" 105 elif [ ! -e "${next_file}" ]; then 106 save_file="${next_file}" 107 break 108 else 109 logger -is -t "$0" \ 110 "${next_file}" is not a regular file, skipped. 111 fi 112 n=$(( ${n} + 1 )) 113 done 114fi 115# 116# 3. Check if the pointer we have in hand is really a regular file or 117# an empty slot, and bail out as that means there is no available slot. 118# 119if [ -e "${save_file}" -a ! -f "${save_file}" ]; then 120 logger -is -t "$0" \ 121 No available slot in "${entropy_dir}", save entropy is aborted. 122 exit 1 123fi 124 125# Save entropy to the selected slot. 126chmod 600 "${save_file}" 2>/dev/null || : 127dd if=/dev/random of="${save_file}" bs=${entropy_save_sz} count=1 2>/dev/null 128 129exit 0 130