#!/usr/bin/env sh set -e EXITCODE=0 # bits of this were adapted from lxc-checkconfig # see also https://github.com/lxc/lxc/blob/lxc-1.0.2/src/lxc/lxc-checkconfig.in possibleConfigs=" /proc/config.gz /boot/config-$(uname -r) /usr/src/linux-$(uname -r)/.config /usr/src/linux/.config " if [ $# -gt 0 ]; then CONFIG="$1" else : "${CONFIG:=/proc/config.gz}" fi if ! command -v zgrep > /dev/null 2>&1; then zgrep() { zcat "$2" | grep "$1" } fi useColor=true if [ "$NO_COLOR" = "1" ] || [ ! -t 1 ]; then useColor=false fi kernelVersion="$(uname -r)" kernelMajor="${kernelVersion%%.*}" kernelMinor="${kernelVersion#$kernelMajor.}" kernelMinor="${kernelMinor%%.*}" is_set() { zgrep "CONFIG_$1=[y|m]" "$CONFIG" > /dev/null } is_set_in_kernel() { zgrep "CONFIG_$1=y" "$CONFIG" > /dev/null } is_set_as_module() { zgrep "CONFIG_$1=m" "$CONFIG" > /dev/null } color() { # if stdout is not a terminal, then don't do color codes. if [ "$useColor" = "false" ]; then return 0 fi codes= if [ "$1" = 'bold' ]; then codes='1' shift fi if [ "$#" -gt 0 ]; then code= case "$1" in # see https://en.wikipedia.org/wiki/ANSI_escape_code#Colors black) code=30 ;; red) code=31 ;; green) code=32 ;; yellow) code=33 ;; blue) code=34 ;; magenta) code=35 ;; cyan) code=36 ;; white) code=37 ;; esac if [ "$code" ]; then codes="${codes:+$codes;}$code" fi fi printf '\033[%sm' "$codes" } wrap_color() { text="$1" shift color "$@" printf '%s' "$text" color reset echo } wrap_good() { echo "$(wrap_color "$1" white): $(wrap_color "$2" green)" } wrap_bad() { echo "$(wrap_color "$1" bold): $(wrap_color "$2" bold red)" } wrap_warning() { wrap_color >&2 "$*" red } check_flag() { if is_set_in_kernel "$1"; then wrap_good "CONFIG_$1" 'enabled' elif is_set_as_module "$1"; then wrap_good "CONFIG_$1" 'enabled (as module)' else wrap_bad "CONFIG_$1" 'missing' EXITCODE=1 fi } check_flags() { for flag in "$@"; do printf -- '- ' check_flag "$flag" done } check_command() { if command -v "$1" > /dev/null 2>&1; then wrap_good "$1 command" 'available' else wrap_bad "$1 command" 'missing' EXITCODE=1 fi } check_device() { if [ -c "$1" ]; then wrap_good "$1" 'present' else wrap_bad "$1" 'missing' EXITCODE=1 fi } if [ ! -e "$CONFIG" ]; then wrap_warning "warning: $CONFIG does not exist, searching other paths for kernel config ..." for tryConfig in $possibleConfigs; do if [ -e "$tryConfig" ]; then CONFIG="$tryConfig" break fi done if [ ! -e "$CONFIG" ]; then wrap_warning "error: cannot find kernel config" wrap_warning " try running this script again, specifying the kernel config:" wrap_warning " CONFIG=/path/to/kernel/.config $0 or $0 /path/to/kernel/.config" exit 1 fi fi wrap_color "info: reading kernel config from $CONFIG ..." white echo echo 'Generally Necessary:' printf -- '- ' if [ "$(stat -f -c %t /sys/fs/cgroup 2> /dev/null)" = '63677270' ]; then wrap_good 'cgroup hierarchy' 'cgroupv2' cgroupv2ControllerFile='/sys/fs/cgroup/cgroup.controllers' if [ -f "$cgroupv2ControllerFile" ]; then echo ' Controllers:' for controller in cpu cpuset io memory pids; do if grep -qE '(^| )'"$controller"'($| )' "$cgroupv2ControllerFile"; then echo " - $(wrap_good "$controller" 'available')" else echo " - $(wrap_bad "$controller" 'missing')" fi done else wrap_bad "$cgroupv2ControllerFile" 'nonexistent??' fi # TODO find an efficient way to check if cgroup.freeze exists in subdir else cgroupSubsystemDir="$(sed -rne '/^[^ ]+ ([^ ]+) cgroup ([^ ]*,)?(cpu|cpuacct|cpuset|devices|freezer|memory)[, ].*$/ { s//\1/p; q }' /proc/mounts)" cgroupDir="$(dirname "$cgroupSubsystemDir")" if [ -d "$cgroupDir/cpu" ] || [ -d "$cgroupDir/cpuacct" ] || [ -d "$cgroupDir/cpuset" ] || [ -d "$cgroupDir/devices" ] || [ -d "$cgroupDir/freezer" ] || [ -d "$cgroupDir/memory" ]; then echo "$(wrap_good 'cgroup hierarchy' 'properly mounted') [$cgroupDir]" else if [ "$cgroupSubsystemDir" ]; then echo "$(wrap_bad 'cgroup hierarchy' 'single mountpoint!') [$cgroupSubsystemDir]" else wrap_bad 'cgroup hierarchy' 'nonexistent??' fi EXITCODE=1 echo " $(wrap_color '(see https://github.com/tianon/cgroupfs-mount)' yellow)" fi fi if [ "$(cat /sys/module/apparmor/parameters/enabled 2> /dev/null)" = 'Y' ]; then printf -- '- ' if command -v apparmor_parser > /dev/null 2>&1; then wrap_good 'apparmor' 'enabled and tools installed' else wrap_bad 'apparmor' 'enabled, but apparmor_parser missing' printf ' ' if command -v apt-get > /dev/null 2>&1; then wrap_color '(use "apt-get install apparmor" to fix this)' elif command -v yum > /dev/null 2>&1; then wrap_color '(your best bet is "yum install apparmor-parser")' else wrap_color '(look for an "apparmor" package for your distribution)' fi EXITCODE=1 fi fi check_flags \ NAMESPACES NET_NS PID_NS IPC_NS UTS_NS \ CGROUPS CGROUP_CPUACCT CGROUP_DEVICE CGROUP_FREEZER CGROUP_SCHED CPUSETS MEMCG \ KEYS \ VETH BRIDGE BRIDGE_NETFILTER \ IP_NF_FILTER IP_NF_MANGLE IP_NF_TARGET_MASQUERADE \ NETFILTER_XT_MATCH_ADDRTYPE \ NETFILTER_XT_MATCH_CONNTRACK \ NETFILTER_XT_MATCH_IPVS \ NETFILTER_XT_MARK \ IP_NF_NAT NF_NAT \ POSIX_MQUEUE # (POSIX_MQUEUE is required for bind-mounting /dev/mqueue into containers) if [ "$kernelMajor" -lt 4 ] || ([ "$kernelMajor" -eq 4 ] && [ "$kernelMinor" -lt 8 ]); then check_flags DEVPTS_MULTIPLE_INSTANCES fi if [ "$kernelMajor" -lt 5 ] || [ "$kernelMajor" -eq 5 -a "$kernelMinor" -le 1 ]; then check_flags NF_NAT_IPV4 fi if [ "$kernelMajor" -lt 5 ] || [ "$kernelMajor" -eq 5 -a "$kernelMinor" -le 2 ]; then check_flags NF_NAT_NEEDED fi # check availability of BPF_CGROUP_DEVICE support if [ "$kernelMajor" -ge 5 ] || ([ "$kernelMajor" -eq 4 ] && [ "$kernelMinor" -ge 15 ]); then check_flags CGROUP_BPF fi echo echo 'Optional Features:' { check_flags USER_NS } { check_flags SECCOMP check_flags SECCOMP_FILTER } { check_flags CGROUP_PIDS } { check_flags MEMCG_SWAP # Kernel v5.8+ removes MEMCG_SWAP_ENABLED. if [ "$kernelMajor" -lt 5 ] || [ "$kernelMajor" -eq 5 -a "$kernelMinor" -le 8 ]; then CODE=${EXITCODE} check_flags MEMCG_SWAP_ENABLED # FIXME this check is cgroupv1-specific if [ -e /sys/fs/cgroup/memory/memory.memsw.limit_in_bytes ]; then echo " $(wrap_color '(cgroup swap accounting is currently enabled)' bold black)" EXITCODE=${CODE} elif is_set MEMCG_SWAP && ! is_set MEMCG_SWAP_ENABLED; then echo " $(wrap_color '(cgroup swap accounting is currently not enabled, you can enable it by setting boot option "swapaccount=1")' bold black)" fi else # Kernel v5.8+ enables swap accounting by default. echo " $(wrap_color '(cgroup swap accounting is currently enabled)' bold black)" fi } { if is_set LEGACY_VSYSCALL_NATIVE; then printf -- '- ' wrap_bad "CONFIG_LEGACY_VSYSCALL_NATIVE" 'enabled' echo " $(wrap_color '(dangerous, provides an ASLR-bypassing target with usable ROP gadgets.)' bold black)" elif is_set LEGACY_VSYSCALL_EMULATE; then printf -- '- ' wrap_good "CONFIG_LEGACY_VSYSCALL_EMULATE" 'enabled' elif is_set LEGACY_VSYSCALL_NONE; then printf -- '- ' wrap_bad "CONFIG_LEGACY_VSYSCALL_NONE" 'enabled' echo " $(wrap_color '(containers using eglibc <= 2.13 will not work. Switch to' bold black)" echo " $(wrap_color ' "CONFIG_VSYSCALL_[NATIVE|EMULATE]" or use "vsyscall=[native|emulate]"' bold black)" echo " $(wrap_color ' on kernel command line. Note that this will disable ASLR for the,' bold black)" echo " $(wrap_color ' VDSO which may assist in exploiting security vulnerabilities.)' bold black)" # else Older kernels (prior to 3dc33bd30f3e, released in v4.40-rc1) do # not have these LEGACY_VSYSCALL options and are effectively # LEGACY_VSYSCALL_EMULATE. Even older kernels are presumably # effectively LEGACY_VSYSCALL_NATIVE. fi } if [ "$kernelMajor" -lt 4 ] || ([ "$kernelMajor" -eq 4 ] && [ "$kernelMinor" -le 5 ]); then check_flags MEMCG_KMEM fi if [ "$kernelMajor" -lt 3 ] || ([ "$kernelMajor" -eq 3 ] && [ "$kernelMinor" -le 18 ]); then check_flags RESOURCE_COUNTERS fi if [ "$kernelMajor" -lt 3 ] || ([ "$kernelMajor" -eq 3 ] && [ "$kernelMinor" -le 13 ]); then netprio=NETPRIO_CGROUP else netprio=CGROUP_NET_PRIO fi if [ "$kernelMajor" -lt 5 ]; then check_flags IOSCHED_CFQ CFQ_GROUP_IOSCHED fi check_flags \ BLK_CGROUP BLK_DEV_THROTTLING \ CGROUP_PERF \ CGROUP_HUGETLB \ NET_CLS_CGROUP $netprio \ CFS_BANDWIDTH FAIR_GROUP_SCHED \ IP_NF_TARGET_REDIRECT \ IP_VS \ IP_VS_NFCT \ IP_VS_PROTO_TCP \ IP_VS_PROTO_UDP \ IP_VS_RR \ SECURITY_SELINUX \ SECURITY_APPARMOR if ! is_set EXT4_USE_FOR_EXT2; then check_flags EXT3_FS EXT3_FS_XATTR EXT3_FS_POSIX_ACL EXT3_FS_SECURITY if ! is_set EXT3_FS || ! is_set EXT3_FS_XATTR || ! is_set EXT3_FS_POSIX_ACL || ! is_set EXT3_FS_SECURITY; then echo " $(wrap_color '(enable these ext3 configs if you are using ext3 as backing filesystem)' bold black)" fi fi check_flags EXT4_FS EXT4_FS_POSIX_ACL EXT4_FS_SECURITY if ! is_set EXT4_FS || ! is_set EXT4_FS_POSIX_ACL || ! is_set EXT4_FS_SECURITY; then if is_set EXT4_USE_FOR_EXT2; then echo " $(wrap_color 'enable these ext4 configs if you are using ext3 or ext4 as backing filesystem' bold black)" else echo " $(wrap_color 'enable these ext4 configs if you are using ext4 as backing filesystem' bold black)" fi fi echo '- Network Drivers:' echo " - \"$(wrap_color 'overlay' blue)\":" check_flags VXLAN BRIDGE_VLAN_FILTERING | sed 's/^/ /' echo ' Optional (for encrypted networks):' check_flags CRYPTO CRYPTO_AEAD CRYPTO_GCM CRYPTO_SEQIV CRYPTO_GHASH \ XFRM XFRM_USER XFRM_ALGO INET_ESP NETFILTER_XT_MATCH_BPF | sed 's/^/ /' if [ "$kernelMajor" -lt 5 ] || [ "$kernelMajor" -eq 5 -a "$kernelMinor" -le 3 ]; then check_flags INET_XFRM_MODE_TRANSPORT | sed 's/^/ /' fi echo " - \"$(wrap_color 'ipvlan' blue)\":" check_flags IPVLAN | sed 's/^/ /' echo " - \"$(wrap_color 'macvlan' blue)\":" check_flags MACVLAN DUMMY | sed 's/^/ /' echo " - \"$(wrap_color 'ftp,tftp client in container' blue)\":" check_flags NF_NAT_FTP NF_CONNTRACK_FTP NF_NAT_TFTP NF_CONNTRACK_TFTP | sed 's/^/ /' # only fail if no storage drivers available CODE=${EXITCODE} EXITCODE=0 STORAGE=1 echo '- Storage Drivers:' echo " - \"$(wrap_color 'btrfs' blue)\":" check_flags BTRFS_FS | sed 's/^/ /' check_flags BTRFS_FS_POSIX_ACL | sed 's/^/ /' [ "$EXITCODE" = 0 ] && STORAGE=0 EXITCODE=0 echo " - \"$(wrap_color 'overlay' blue)\":" check_flags OVERLAY_FS | sed 's/^/ /' [ "$EXITCODE" = 0 ] && STORAGE=0 EXITCODE=0 echo " - \"$(wrap_color 'zfs' blue)\":" printf ' - ' check_device /dev/zfs printf ' - ' check_command zfs printf ' - ' check_command zpool [ "$EXITCODE" = 0 ] && STORAGE=0 EXITCODE=0 EXITCODE=$CODE [ "$STORAGE" = 1 ] && EXITCODE=1 echo check_limit_over() { if [ "$(cat "$1")" -le "$2" ]; then wrap_bad "- $1" "$(cat "$1")" wrap_color " This should be set to at least $2, for example set: sysctl -w kernel/keys/root_maxkeys=1000000" bold black EXITCODE=1 else wrap_good "- $1" "$(cat "$1")" fi } echo 'Limits:' check_limit_over /proc/sys/kernel/keys/root_maxkeys 10000 echo exit $EXITCODE