security-misc/usr/libexec/security-misc/hide-hardware-info
2024-05-11 13:18:36 +10:00

134 lines
3.7 KiB
Bash
Executable File

#!/bin/bash
## Copyright (C) 2012 - 2024 ENCRYPTED SUPPORT LP <adrelanos@whonix.org>
## See the file COPYING for copying conditions.
set -e
run_cmd() {
echo "INFO: normal executing : $@"
"$@"
}
run_cmd_whitelist() {
echo "INFO: whitelist executing: $@"
"$@"
}
echo "$0: INFO: START"
sysfs_whitelist=1
cpuinfo_whitelist=1
sysfs=1
## https://www.kicksecure.com/wiki/Security-misc#selinux
selinux=0
shopt -s nullglob
## Allows for disabling the whitelist.
for i in /etc/hide-hardware-info.d/*.conf
do
bash -n "${i}"
source "${i}"
done
create_whitelist() {
if [ "${1}" = "sysfs" ]; then
whitelist_path="/sys"
elif [ "${1}" = "cpuinfo" ]; then
whitelist_path="/proc/cpuinfo"
else
echo "ERROR: ${1} is not a correct parameter."
exit 1
fi
if grep -q "${1}" /etc/group; then
## Changing the permissions of /sys recursively
## causes errors as the permissions of /sys/kernel/debug
## and /sys/fs/cgroup cannot be changed.
run_cmd_whitelist chgrp --quiet --recursive "${1}" "${whitelist_path}" || true
run_cmd_whitelist chmod o-rwx "${whitelist_path}"
else
echo "ERROR: The ${1} group does not exist, the ${1} whitelist was not created."
fi
}
## sysfs and debugfs expose a lot of information
## that should not be accessible by an unprivileged
## user which includes hardware info, debug info and
## more. This restricts /sys, /proc/cpuinfo, /proc/bus
## and /proc/scsi to the root user only. This hides
## many hardware identifiers from ordinary users
## and increases security.
for i in /proc/cpuinfo /proc/bus /proc/scsi /sys
do
if [ -e "${i}" ]; then
if [ "${i}" = "/sys" ]; then
if [ "${sysfs}" = "1" ]; then
## Whitelist for /sys.
if [ "${sysfs_whitelist}" = "1" ]; then
create_whitelist sysfs
else
echo "INFO: The sysfs whitelist is not enabled. Some things may not work properly. Full sysfs hardening..."
run_cmd chmod og-rwx /sys
fi
fi
elif [ "${i}" = "/proc/cpuinfo" ]; then
if [ "${cpuinfo_whitelist}" = "1" ]; then
create_whitelist cpuinfo
else
echo "INFO: The cpuinfo whitelist is not enabled. Some things may not work properly. Full cpuinfo hardening..."
run_cmd chmod og-rwx /proc/cpuinfo
fi
else
run_cmd chmod og-rwx "${i}"
fi
else
## /proc/scsi doesn't exist on Debian so errors
## are expected here.
if ! [ "${i}" = "/proc/scsi" ]; then
echo "ERROR: ${i} could not be found."
fi
fi
done
if [ "${sysfs}" = "1" ]; then
## restrict permissions on everything but
## what is needed
for i in /sys/* /sys/fs/*
do
## Using '|| true':
## https://github.com/Kicksecure/security-misc/pull/108
if [ "${sysfs_whitelist}" = "1" ]; then
run_cmd chmod o-rwx "${i}" || true
else
run_cmd chmod og-rwx "${i}" || true
fi
done
## polkit needs stat access to /sys/fs/cgroup
## to function properly
run_cmd chmod o+rx /sys /sys/fs
## on SELinux systems, at least /sys/fs/selinux
## must be visible to unprivileged users, else
## SELinux userspace utilities will not function
## properly
if [ -d /sys/fs/selinux ]; then
echo "INFO: SELinux detected because folder /sys/fs/selinux exists. See also:"
echo "https://www.kicksecure.com/wiki/Security-misc#selinux"
if [ "${selinux}" = "1" ]; then
run_cmd chmod o+rx /sys /sys/fs /sys/fs/selinux
echo "INFO: SELinux mode enabled. Restrictions loosened slightly in order to allow userspace utilities to function."
else
echo "INFO: SELinux detected, but SELinux mode is not enabled. Some userspace utilities may not work properly."
fi
fi
fi
echo "$0: INFO: END"