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freebsd-dev/libexec/save-entropy/save-entropy.sh

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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.
2001-01-11 13:01:20 +00:00
#!/bin/sh
#
libexec: adoption of SPDX licensing ID tags. Mainly focus on files that use BSD 2-Clause license, however the tool I was using misidentified many licenses so this was mostly a manual - error prone - task. The Software Package Data Exchange (SPDX) group provides a specification to make it easier for automated tools to detect and summarize well known opensource licenses. We are gradually adopting the specification, noting that the tags are considered only advisory and do not, in any way, superceed or replace the license texts. No functional change intended.
2017-11-27 15:25:02 +00:00
# SPDX-License-Identifier: BSD-2-Clause-FreeBSD
#
1. Use install -d to create the entropy_dir if missing so that we can do it all in one command, with no permissions race. 2. Simplify the rotation logic by cd'ing into the directory, with a test to make sure that it succeeds. 3. Remove any files numbered higher than entropy_save_num. This helps when the user reduces the number, and may be useful for other purposes down the road. 4. Simplify the rotation logic by first testing the common case (it's a regular file) then testing if something else exists with the same name using elif. Also switch from using jot to simpler countdown format. 5. Fix logger lines and error messages to be more consistent, and wrap the code more consistently in the 80 column range. The "not a regular file" error message was mistakenly wrapped entirely in "quotes" which caused logger to include line-wrapping whitespace. Change that to wrap only the variables in quotes, which is both consistent and works better. 6. Update copyright to reflect the fact that changes were made this year. Parts of 2-4 were taken from etc/periodic/daily/310.accounting
2012-09-04 16:00:51 +00:00
# Copyright (c) 2001-2006,2012 Douglas Barton, dougb@FreeBSD.org
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.
2001-01-11 13:01:20 +00:00
# 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.
1. Use install -d to create the entropy_dir if missing so that we can do it all in one command, with no permissions race. 2. Simplify the rotation logic by cd'ing into the directory, with a test to make sure that it succeeds. 3. Remove any files numbered higher than entropy_save_num. This helps when the user reduces the number, and may be useful for other purposes down the road. 4. Simplify the rotation logic by first testing the common case (it's a regular file) then testing if something else exists with the same name using elif. Also switch from using jot to simpler countdown format. 5. Fix logger lines and error messages to be more consistent, and wrap the code more consistently in the 80 column range. The "not a regular file" error message was mistakenly wrapped entirely in "quotes" which caused logger to include line-wrapping whitespace. Change that to wrap only the variables in quotes, which is both consistent and works better. 6. Update copyright to reflect the fact that changes were made this year. Parts of 2-4 were taken from etc/periodic/daily/310.accounting
2012-09-04 16:00:51 +00:00
# Originally developed by Doug Barton, dougb@FreeBSD.org
Move the process of storing entropy from /dev/random and reseeding with it at boot time closer to the way we want it to be in the final version. * Move the default directory to /var/db/entropy * Run the entropy saving cron job every 11 minutes. This seems to be a better default, although still bikeshed material. * Feed /dev/random some cheesy "entropy" from various commands and files before the disks are mounted. This gives /dev/random a better chance of running without blocking early. * Move the reseeding with previously stored entropy to the point immediately after the disks are mounted. * Make the harvesting script a little safer in regards to the possibility of accidentally overwriting something other than a regular file.
2001-01-14 07:18:31 +00:00
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.
2001-01-11 13:01:20 +00:00
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
1. Attempt to take one bullet out of the foot-shooting gun by silently ignoring errors when sourcing rc.conf* files. The most common error occurs when users put a command of some sort into those files. (ifconfig is a popular choice) 2. Make the file rotation logic simpler by starting one down from the "top" of the list, rather than at the top. 3. Try to make file rotation more secure by calling unlink(1) on all new file names before rotating an old file to the new name, rather than merely calling 'rm -f' on any files that exceed the number of files to save.
2006-08-28 06:41:50 +00:00
source_rc_confs 2>/dev/null
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.
2001-01-11 13:01:20 +00:00
elif [ -r /etc/rc.conf ]; then
1. Attempt to take one bullet out of the foot-shooting gun by silently ignoring errors when sourcing rc.conf* files. The most common error occurs when users put a command of some sort into those files. (ifconfig is a popular choice) 2. Make the file rotation logic simpler by starting one down from the "top" of the list, rather than at the top. 3. Try to make file rotation more secure by calling unlink(1) on all new file names before rotating an old file to the new name, rather than merely calling 'rm -f' on any files that exceed the number of files to save.
2006-08-28 06:41:50 +00:00
. /etc/rc.conf 2>/dev/null
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.
2001-01-11 13:01:20 +00:00
fi
Don't save entropy inside jails. As of r126744, we no longer feed the entropy device in jails upon start, and collecting them is no longer useful. PR: conf/126744 Submitted by: Eugene Grosbein <eugen grosbein net> (with minor changes) MFC after: 1 week Approved by: so (des)
2014-07-22 06:40:27 +00:00
[ $(/sbin/sysctl -n security.jail.jailed) = 0 ] || exit 0
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.
2001-01-11 13:01:20 +00:00
case ${entropy_dir} in
[Nn][Oo])
exit 0
;;
*)
Move the process of storing entropy from /dev/random and reseeding with it at boot time closer to the way we want it to be in the final version. * Move the default directory to /var/db/entropy * Run the entropy saving cron job every 11 minutes. This seems to be a better default, although still bikeshed material. * Feed /dev/random some cheesy "entropy" from various commands and files before the disks are mounted. This gives /dev/random a better chance of running without blocking early. * Move the reseeding with previously stored entropy to the point immediately after the disks are mounted. * Make the harvesting script a little safer in regards to the possibility of accidentally overwriting something other than a regular file.
2001-01-14 07:18:31 +00:00
entropy_dir=${entropy_dir:-/var/db/entropy}
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.
2001-01-11 13:01:20 +00:00
;;
esac
This is the much-discussed major upgrade to the random(4) device, known to you all as /dev/random. This code has had an extensive rewrite and a good series of reviews, both by the author and other parties. This means a lot of code has been simplified. Pluggable structures for high-rate entropy generators are available, and it is most definitely not the case that /dev/random can be driven by only a hardware souce any more. This has been designed out of the device. Hardware sources are stirred into the CSPRNG (Yarrow, Fortuna) like any other entropy source. Pluggable modules may be written by third parties for additional sources. The harvesting structures and consequently the locking have been simplified. Entropy harvesting is done in a more general way (the documentation for this will follow). There is some GREAT entropy to be had in the UMA allocator, but it is disabled for now as messing with that is likely to annoy many people. The venerable (but effective) Yarrow algorithm, which is no longer supported by its authors now has an alternative, Fortuna. For now, Yarrow is retained as the default algorithm, but this may be changed using a kernel option. It is intended to make Fortuna the default algorithm for 11.0. Interested parties are encouraged to read ISBN 978-0-470-47424-2 "Cryptography Engineering" By Ferguson, Schneier and Kohno for Fortuna's gory details. Heck, read it anyway. Many thanks to Arthur Mesh who did early grunt work, and who got caught in the crossfire rather more than he deserved to. My thanks also to folks who helped me thresh this out on whiteboards and in the odd "Hallway track", or otherwise. My Nomex pants are on. Let the feedback commence! Reviewed by: trasz,des(partial),imp(partial?),rwatson(partial?) Approved by: so(des)
2014-10-30 21:21:53 +00:00
entropy_save_sz=${entropy_save_sz:-4096}
Add a system to save entropy from /dev/random periodically so that it can be used to reseed at boot time. This will greatly increase the chances that there will be sufficient entropy available at boot time to prevent long delays. For /etc/rc, remove the vmstat and iostat runs from the attempt to provide some cheesy randomness if the files fail, since those programs are dynamically linked, and ldd seems to want some randomness to do its magic. Guidance and parameters for this project were provided by Mark Murray, based on the requirements of the Yarrow algorithm. Some helpful suggestions for implementation (including the tip about iostat and vmstat) were provided by Sheldon Hearn. All blame for problems or mistakes is mine of course.
2001-01-11 13:01:20 +00:00
entropy_save_num=${entropy_save_num:-8}
if [ ! -d "${entropy_dir}" ]; then
1. Use install -d to create the entropy_dir if missing so that we can do it all in one command, with no permissions race. 2. Simplify the rotation logic by cd'ing into the directory, with a test to make sure that it succeeds. 3. Remove any files numbered higher than entropy_save_num. This helps when the user reduces the number, and may be useful for other purposes down the road. 4. Simplify the rotation logic by first testing the common case (it's a regular file) then testing if something else exists with the same name using elif. Also switch from using jot to simpler countdown format. 5. Fix logger lines and error messages to be more consistent, and wrap the code more consistently in the 80 column range. The "not a regular file" error message was mistakenly wrapped entirely in "quotes" which caused logger to include line-wrapping whitespace. Change that to wrap only the variables in quotes, which is both consistent and works better. 6. Update copyright to reflect the fact that changes were made this year. Parts of 2-4 were taken from etc/periodic/daily/310.accounting
2012-09-04 16:00:51 +00:00
install -d -o operator -g operator -m 0700 "${entropy_dir}" || {
logger -is -t "$0" The entropy directory "${entropy_dir}" does \
not exist, and cannot be created. Therefore no entropy can \
be saved.; exit 1; }
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.
2001-01-11 13:01:20 +00:00
fi
1. Use install -d to create the entropy_dir if missing so that we can do it all in one command, with no permissions race. 2. Simplify the rotation logic by cd'ing into the directory, with a test to make sure that it succeeds. 3. Remove any files numbered higher than entropy_save_num. This helps when the user reduces the number, and may be useful for other purposes down the road. 4. Simplify the rotation logic by first testing the common case (it's a regular file) then testing if something else exists with the same name using elif. Also switch from using jot to simpler countdown format. 5. Fix logger lines and error messages to be more consistent, and wrap the code more consistently in the 80 column range. The "not a regular file" error message was mistakenly wrapped entirely in "quotes" which caused logger to include line-wrapping whitespace. Change that to wrap only the variables in quotes, which is both consistent and works better. 6. Update copyright to reflect the fact that changes were made this year. Parts of 2-4 were taken from etc/periodic/daily/310.accounting
2012-09-04 16:00:51 +00:00
cd "${entropy_dir}" || {
logger -is -t "$0" Cannot cd to the entropy directory: "${entropy_dir}". \
Entropy file rotation is aborted.; exit 1; }
for f in saved-entropy.*; do
case "${f}" in saved-entropy.\*) continue ;; esac # No files match
[ ${f#saved-entropy\.} -ge ${entropy_save_num} ] && unlink ${f}
done
Add a system to save entropy from /dev/random periodically so that it can be used to reseed at boot time. This will greatly increase the chances that there will be sufficient entropy available at boot time to prevent long delays. For /etc/rc, remove the vmstat and iostat runs from the attempt to provide some cheesy randomness if the files fail, since those programs are dynamically linked, and ldd seems to want some randomness to do its magic. Guidance and parameters for this project were provided by Mark Murray, based on the requirements of the Yarrow algorithm. Some helpful suggestions for implementation (including the tip about iostat and vmstat) were provided by Sheldon Hearn. All blame for problems or mistakes is mine of course.
2001-01-11 13:01:20 +00:00
umask 377
1. Use install -d to create the entropy_dir if missing so that we can do it all in one command, with no permissions race. 2. Simplify the rotation logic by cd'ing into the directory, with a test to make sure that it succeeds. 3. Remove any files numbered higher than entropy_save_num. This helps when the user reduces the number, and may be useful for other purposes down the road. 4. Simplify the rotation logic by first testing the common case (it's a regular file) then testing if something else exists with the same name using elif. Also switch from using jot to simpler countdown format. 5. Fix logger lines and error messages to be more consistent, and wrap the code more consistently in the 80 column range. The "not a regular file" error message was mistakenly wrapped entirely in "quotes" which caused logger to include line-wrapping whitespace. Change that to wrap only the variables in quotes, which is both consistent and works better. 6. Update copyright to reflect the fact that changes were made this year. Parts of 2-4 were taken from etc/periodic/daily/310.accounting
2012-09-04 16:00:51 +00:00
n=$(( ${entropy_save_num} - 1 ))
while [ ${n} -ge 1 ]; do
if [ -f "saved-entropy.${n}" ]; then
mv "saved-entropy.${n}" "saved-entropy.$(( ${n} + 1 ))"
elif [ -e "saved-entropy.${n}" -o -L "saved-entropy.${n}" ]; then
logger -is -t "$0" \
"${entropy_dir}/saved-entropy.${n}" is not a regular file, and so \
it will not be rotated. Entropy file rotation is aborted.
exit 1
Add a system to save entropy from /dev/random periodically so that it can be used to reseed at boot time. This will greatly increase the chances that there will be sufficient entropy available at boot time to prevent long delays. For /etc/rc, remove the vmstat and iostat runs from the attempt to provide some cheesy randomness if the files fail, since those programs are dynamically linked, and ldd seems to want some randomness to do its magic. Guidance and parameters for this project were provided by Mark Murray, based on the requirements of the Yarrow algorithm. Some helpful suggestions for implementation (including the tip about iostat and vmstat) were provided by Sheldon Hearn. All blame for problems or mistakes is mine of course.
2001-01-11 13:01:20 +00:00
fi
1. Use install -d to create the entropy_dir if missing so that we can do it all in one command, with no permissions race. 2. Simplify the rotation logic by cd'ing into the directory, with a test to make sure that it succeeds. 3. Remove any files numbered higher than entropy_save_num. This helps when the user reduces the number, and may be useful for other purposes down the road. 4. Simplify the rotation logic by first testing the common case (it's a regular file) then testing if something else exists with the same name using elif. Also switch from using jot to simpler countdown format. 5. Fix logger lines and error messages to be more consistent, and wrap the code more consistently in the 80 column range. The "not a regular file" error message was mistakenly wrapped entirely in "quotes" which caused logger to include line-wrapping whitespace. Change that to wrap only the variables in quotes, which is both consistent and works better. 6. Update copyright to reflect the fact that changes were made this year. Parts of 2-4 were taken from etc/periodic/daily/310.accounting
2012-09-04 16:00:51 +00:00
n=$(( ${n} - 1 ))
Add a system to save entropy from /dev/random periodically so that it can be used to reseed at boot time. This will greatly increase the chances that there will be sufficient entropy available at boot time to prevent long delays. For /etc/rc, remove the vmstat and iostat runs from the attempt to provide some cheesy randomness if the files fail, since those programs are dynamically linked, and ldd seems to want some randomness to do its magic. Guidance and parameters for this project were provided by Mark Murray, based on the requirements of the Yarrow algorithm. Some helpful suggestions for implementation (including the tip about iostat and vmstat) were provided by Sheldon Hearn. All blame for problems or mistakes is mine of course.
2001-01-11 13:01:20 +00:00
done
1. Use install -d to create the entropy_dir if missing so that we can do it all in one command, with no permissions race. 2. Simplify the rotation logic by cd'ing into the directory, with a test to make sure that it succeeds. 3. Remove any files numbered higher than entropy_save_num. This helps when the user reduces the number, and may be useful for other purposes down the road. 4. Simplify the rotation logic by first testing the common case (it's a regular file) then testing if something else exists with the same name using elif. Also switch from using jot to simpler countdown format. 5. Fix logger lines and error messages to be more consistent, and wrap the code more consistently in the 80 column range. The "not a regular file" error message was mistakenly wrapped entirely in "quotes" which caused logger to include line-wrapping whitespace. Change that to wrap only the variables in quotes, which is both consistent and works better. 6. Update copyright to reflect the fact that changes were made this year. Parts of 2-4 were taken from etc/periodic/daily/310.accounting
2012-09-04 16:00:51 +00:00
dd if=/dev/random of=saved-entropy.1 bs=${entropy_save_sz} count=1 2>/dev/null
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.
2001-01-11 13:01:20 +00:00
exit 0
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