freebsd-skq/etc/rc.d/random
delphij faa6908918 Tighten /entropy permissions.
PR:		219527
Reported by:	Lu Tung-Pin <lutungpin at openmailbox.org>
Submitted by:	jilles
MFC after:	3 days
2017-05-27 06:24:06 +00:00

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#!/bin/sh
#
# $FreeBSD$
#
# PROVIDE: random
# REQUIRE: FILESYSTEMS
# BEFORE: netif
# KEYWORD: nojail shutdown
. /etc/rc.subr
name="random"
desc="Harvest and save entropy for random device"
start_cmd="random_start"
stop_cmd="random_stop"
extra_commands="saveseed"
saveseed_cmd="${name}_stop"
save_dev_random()
{
oumask=`umask`
umask 077
for f ; do
debug "saving entropy to $f"
dd if=/dev/random of="$f" bs=4096 count=1 status=none &&
chmod 600 "$f"
done
umask ${oumask}
}
feed_dev_random()
{
for f ; do
if [ -f "$f" -a -r "$f" -a -s "$f" ] ; then
if dd if="$f" of=/dev/random bs=4096 2>/dev/null ; then
debug "entropy read from $f"
rm -f "$f"
fi
fi
done
}
random_start()
{
if [ ${harvest_mask} -gt 0 ]; then
echo -n 'Setting up harvesting: '
${SYSCTL} kern.random.harvest.mask=${harvest_mask} > /dev/null
${SYSCTL_N} kern.random.harvest.mask_symbolic
fi
echo -n 'Feeding entropy: '
if [ ! -w /dev/random ] ; then
warn "/dev/random is not writeable"
return 1
fi
# Reseed /dev/random with previously stored entropy.
case ${entropy_dir:=/var/db/entropy} in
[Nn][Oo])
;;
*)
if [ -d "${entropy_dir}" ] ; then
feed_dev_random "${entropy_dir}"/*
fi
;;
esac
case ${entropy_file:=/entropy} in
[Nn][Oo])
;;
*)
feed_dev_random "${entropy_file}" /var/db/entropy-file
save_dev_random "${entropy_file}"
;;
esac
case ${entropy_boot_file:=/boot/entropy} in
[Nn][Oo])
;;
*)
save_dev_random "${entropy_boot_file}"
;;
esac
echo '.'
}
random_stop()
{
# Write some entropy so when the machine reboots /dev/random
# can be reseeded
#
case ${entropy_file:=/entropy} in
[Nn][Oo])
;;
*)
echo -n 'Writing entropy file:'
rm -f ${entropy_file} 2> /dev/null
oumask=`umask`
umask 077
if touch ${entropy_file} 2> /dev/null; then
entropy_file_confirmed="${entropy_file}"
else
# Try this as a reasonable alternative for read-only
# roots, diskless workstations, etc.
rm -f /var/db/entropy-file 2> /dev/null
if touch /var/db/entropy-file 2> /dev/null; then
entropy_file_confirmed=/var/db/entropy-file
fi
fi
case ${entropy_file_confirmed} in
'')
warn 'write failed (read-only fs?)'
;;
*)
dd if=/dev/random of=${entropy_file_confirmed} \
bs=4096 count=1 2> /dev/null ||
warn 'write failed (unwriteable file or full fs?)'
echo '.'
;;
esac
umask ${oumask}
;;
esac
case ${entropy_boot_file:=/boot/entropy} in
[Nn][Oo])
;;
*)
echo -n 'Writing early boot entropy file:'
rm -f ${entropy_boot_file} 2> /dev/null
oumask=`umask`
umask 077
if touch ${entropy_boot_file} 2> /dev/null; then
entropy_boot_file_confirmed="${entropy_boot_file}"
fi
case ${entropy_boot_file_confirmed} in
'')
warn 'write failed (read-only fs?)'
;;
*)
dd if=/dev/random of=${entropy_boot_file_confirmed} \
bs=4096 count=1 2> /dev/null ||
warn 'write failed (unwriteable file or full fs?)'
echo '.'
;;
esac
umask ${oumask}
;;
esac
}
load_rc_config $name
run_rc_command "$1"