From 27a803d631193a49a09c117d72371fca3bf4869c Mon Sep 17 00:00:00 2001 From: Doug Barton Date: Thu, 11 Jan 2001 13:01:20 +0000 Subject: [PATCH] Add a system to save entropy from /dev/random periodically so that it can be used to reseed at boot time. This will greatly increase the chances that there will be sufficient entropy available at boot time to prevent long delays. For /etc/rc, remove the vmstat and iostat runs from the attempt to provide some cheesy randomness if the files fail, since those programs are dynamically linked, and ldd seems to want some randomness to do its magic. Guidance and parameters for this project were provided by Mark Murray, based on the requirements of the Yarrow algorithm. Some helpful suggestions for implementation (including the tip about iostat and vmstat) were provided by Sheldon Hearn. All blame for problems or mistakes is mine of course. --- etc/crontab | 3 + etc/defaults/rc.conf | 3 + etc/mtree/BSD.root.dist | 4 ++ etc/rc | 36 ++++++++---- libexec/Makefile | 1 + libexec/save-entropy/Makefile | 10 ++++ libexec/save-entropy/save-entropy.sh | 82 ++++++++++++++++++++++++++++ 7 files changed, 129 insertions(+), 10 deletions(-) create mode 100644 libexec/save-entropy/Makefile create mode 100755 libexec/save-entropy/save-entropy.sh diff --git a/etc/crontab b/etc/crontab index 784980c48d63..1f0950efcbbc 100644 --- a/etc/crontab +++ b/etc/crontab @@ -8,6 +8,9 @@ HOME=/var/log # #minute hour mday month wday who command # +# save some entropy so that /dev/random can reseed on boot +*/3 * * * * operator /usr/libexec/save-entropy +# */5 * * * * root /usr/libexec/atrun # # rotate log files every hour, if necessary diff --git a/etc/defaults/rc.conf b/etc/defaults/rc.conf index b76156409d53..7e3d2767c48f 100644 --- a/etc/defaults/rc.conf +++ b/etc/defaults/rc.conf @@ -324,6 +324,9 @@ start_vinum="" # set to YES to start vinum unaligned_print="YES" # print unaligned access warnings on the alpha (or NO). entropy_file="/entropy" # Set to NO to disable caching entropy through reboots. # /var/db/entropy is preferred if / is not available. +entropy_dir="/.entropy" # Set to NO to disable caching entropy via cron. +entropy_save_sz="2048" # Size of the entropy cache files. +entropy_save_num="8" # Number of entropy cache files to save. ############################################################## ### Define source_rc_confs, the mechanism used by /etc/rc.* ## diff --git a/etc/mtree/BSD.root.dist b/etc/mtree/BSD.root.dist index e6e9a4d64c3a..0fc9833f2040 100644 --- a/etc/mtree/BSD.root.dist +++ b/etc/mtree/BSD.root.dist @@ -5,6 +5,10 @@ /set type=dir uname=root gname=wheel mode=0755 . +/set type=dir uname=operator gname=operator mode=0700 + .entropy + .. +/set type=dir uname=root gname=wheel mode=0755 bin .. boot diff --git a/etc/rc b/etc/rc index d3db56a37c40..3f9fba7cc905 100644 --- a/etc/rc +++ b/etc/rc @@ -102,16 +102,34 @@ chkdepend NIS nis_client_enable portmap portmap_enable # First pass at entropy recovery so the rebooting /dev/random can reseed. # +feed_dev_random() { + if [ -f "${1}" -a -r "${1}" -a -s "${1}" ]; then + echo "Using ${1} as an entropy file" + cat ${1} > /dev/random 2> /dev/random && + entropy_reseeded=yes + fi +} + case ${entropy_file} in [Nn][Oo] | '') ;; *) if [ -w /dev/random ]; then - if [ -f "${entropy_file}" -a -r "${entropy_file}" -a \ - -s "${entropy_file}" ]; then - echo "Using ${entropy_file} as an entropy file" - cat ${entropy_file} > /dev/random 2> /dev/random - entropy_reseeded=yes + feed_dev_random "${entropy_file}" + fi + ;; +esac + +case ${entropy_dir} in +[Nn][Oo]) + ;; +*) + entropy_dir=${entropy_dir:-/.entropy} + if [ -d "${entropy_dir}" ]; then + if [ -w /dev/random ]; then + for seedfile in ${entropy_dir}/*; do + feed_dev_random "${seedfile}" + done fi fi ;; @@ -219,20 +237,18 @@ yes) if [ -w /dev/random ]; then if [ -f "${entropy_file}" -a -r "${entropy_file}" -a \ -s "${entropy_file}" ]; then - echo "Using ${entropy_file} as an entropy file" - cat ${entropy_file} > /dev/random 2> /dev/random + feed_dev_random "${entropy_file}" elif [ "${entropy_file}" != /var/db/entropy -a \ -f /var/db/entropy -a -r /var/db/entropy -a \ -s /var/db/entropy ]; then - echo 'Using /var/db/entropy as an entropy file' - cat /var/db/entropy > /dev/random 2> /dev/random + feed_dev_random /var/db/entropy else echo "Can't use ${entropy_file} as an entropy file, trying other sources" # XXX temporary until we can get the entropy # harvesting rate up # Entropy below is not great, # but better than nothing. - (ps -gauxwww; iostat; vmstat; sysctl -a; + (ps -gauxwww; sysctl -a; dmesg) | /bin/dd of=/dev/random bs=8k 2>/dev/null ( for i in /etc /var/run ; do cd $i ; ls -al ; cat * diff --git a/libexec/Makefile b/libexec/Makefile index c051e13ff89e..6ee31ed4ab73 100644 --- a/libexec/Makefile +++ b/libexec/Makefile @@ -22,6 +22,7 @@ SUBDIR= atrun \ rpc.rwalld \ rpc.sprayd \ rshd \ + save-entropy \ talkd \ tftpd \ xtend \ diff --git a/libexec/save-entropy/Makefile b/libexec/save-entropy/Makefile new file mode 100644 index 000000000000..c3de2caaf45c --- /dev/null +++ b/libexec/save-entropy/Makefile @@ -0,0 +1,10 @@ +# $FreeBSD$ + +NOMAN= noman + +beforeinstall: + ${INSTALL} -c -o operator -g operator -m 500 \ + ${.CURDIR}/save-entropy.sh ${DESTDIR}${BINDIR}/save-entropy + +.include + diff --git a/libexec/save-entropy/save-entropy.sh b/libexec/save-entropy/save-entropy.sh new file mode 100755 index 000000000000..4a84fd741959 --- /dev/null +++ b/libexec/save-entropy/save-entropy.sh @@ -0,0 +1,82 @@ +#!/bin/sh +# +# Copyright (c) 2001 The FreeBSD Project +# All rights reserved. +# +# Redistribution and use in source and binary forms, with or without +# modification, are permitted provided that the following conditions +# are met: +# 1. Redistributions of source code must retain the above copyright +# notice, this list of conditions and the following disclaimer. +# 2. Redistributions in binary form must reproduce the above copyright +# notice, this list of conditions and the following disclaimer in the +# documentation and/or other materials provided with the distribution. +# +# THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND +# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE +# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE +# ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE +# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL +# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS +# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) +# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT +# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY +# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF +# SUCH DAMAGE. +# +# $FreeBSD$ + +# This script is called by cron to store bits of randomness which are +# then used to seed /dev/random on boot. + +PATH=/bin:/usr/bin + +# If there is a global system configuration file, suck it in. +# +if [ -r /etc/defaults/rc.conf ]; then + . /etc/defaults/rc.conf + source_rc_confs +elif [ -r /etc/rc.conf ]; then + . /etc/rc.conf +fi + +case ${entropy_dir} in +[Nn][Oo]) + exit 0 + ;; +*) + entropy_dir=${entropy_dir:-/.entropy} + ;; +esac + +entropy_save_sz=${entropy_save_sz:-2048} +entropy_save_num=${entropy_save_num:-8} +entropy_save_jot=$(($entropy_save_num - 1)) + +if [ ! -d "${entropy_dir}" ]; then + umask 077 + mkdir "${entropy_dir}" || { + logger -is The entropy directory "${entropy_dir}" does not \ +exist, and cannot be created. Therefore no entropy can be saved. ; + exit 1;} + /usr/sbin/chown operator:operator "${entropy_dir}" + chmod 0700 "${entropy_dir}" +fi + +rm -f "${entropy_dir}/saved-entropy.${entropy_save_num}" + +umask 377 + +for file_num in `jot ${entropy_save_jot} ${entropy_save_jot} 1`; do + if [ -f "${entropy_dir}/saved-entropy.${file_num}" ]; then + new_num=$(($file_num + 1)) + mv "${entropy_dir}/saved-entropy.${file_num}" \ + "${entropy_dir}/saved-entropy.${new_num}" + fi +done + +dd if=/dev/random of="${entropy_dir}/saved-entropy.1" \ + bs=2048 count=1 2> /dev/null + +exit 0 +