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3e454f1817
spectre-meltdown-checker/spectre-meltdown-checker.sh
Stéphane Lesimple 3e454f1817 fix(offline): report unknown when too few info 
In offline mode, in the worst case where an invalid
config file is given, and we have no vmlinux image
nor System.map, the script was reporting Variant 2
and Variant 3 as vulnerable in the global status.
Replace this by a proper pair of UNKNOWNs
2018-01-23 22:20:34 +01:00

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#! /bin/sh
# Spectre & Meltdown checker
#
# Check for the latest version at:
# https://github.com/speed47/spectre-meltdown-checker
# git clone https://github.com/speed47/spectre-meltdown-checker.git
# or wget https://raw.githubusercontent.com/speed47/spectre-meltdown-checker/master/spectre-meltdown-checker.sh
#
# Stephane Lesimple
#
VERSION=0.32
show_usage()
{
cat <<EOF
Usage:
Live mode: `basename $0` [options] [--live]
Offline mode: `basename $0` [options] [--kernel <vmlinux_file>] [--config <kernel_config>] [--map <kernel_map_file>]
Modes:
Two modes are available.
First mode is the "live" mode (default), it does its best to find information about the currently running kernel.
To run under this mode, just start the script without any option (you can also use --live explicitly)
Second mode is the "offline" mode, where you can inspect a non-running kernel.
You'll need to specify the location of the vmlinux file, config and System.map files:
--kernel vmlinux_file Specify a (possibly compressed) vmlinux file
--config kernel_config Specify a kernel config file
--map kernel_map_file Specify a kernel System.map file
Options:
--no-color Don't use color codes
--verbose, -v Increase verbosity level
--no-sysfs Don't use the /sys interface even if present
--coreos Special mode for CoreOS (use an ephemeral toolbox to inspect kernel)
--batch text Produce machine readable output, this is the default if --batch is specified alone
--batch json Produce JSON output formatted for Puppet, Ansible, Chef...
--batch nrpe Produce machine readable output formatted for NRPE
--variant [1,2,3] Specify which variant you'd like to check, by default all variants are checked
Can be specified multiple times (e.g. --variant 2 --variant 3)
Return codes:
0 (not vulnerable), 2 (vulnerable), 3 (unknown), 255 (error)
IMPORTANT:
A false sense of security is worse than no security at all.
Please use the --disclaimer option to understand exactly what this script does.
EOF
}
show_disclaimer()
{
cat <<EOF
Disclaimer:
This tool does its best to determine whether your system is immune (or has proper mitigations in place) for the
collectively named "speculative execution" vulnerabilities. It doesn't attempt to run any kind of exploit, and can't guarantee
that your system is secure, but rather helps you verifying whether your system has the known correct mitigations in place.
However, some mitigations could also exist in your kernel that this script doesn't know (yet) how to detect, or it might
falsely detect mitigations that in the end don't work as expected (for example, on backported or modified kernels).
Your system exposure also depends on your CPU. As of now, AMD and ARM processors are marked as immune to some or all of these
vulnerabilities (except some specific ARM models). All Intel processors manufactured since circa 1995 are thought to be vulnerable.
Whatever processor one uses, one might seek more information from the manufacturer of that processor and/or of the device
in which it runs.
The nature of the discovered vulnerabilities being quite new, the landscape of vulnerable processors can be expected
to change over time, which is why this script makes the assumption that all CPUs are vulnerable, except if the manufacturer
explicitly stated otherwise in a verifiable public announcement.
This tool has been released in the hope that it'll be useful, but don't use it to jump to conclusions about your security.
EOF
}
# parse options
opt_kernel=''
opt_config=''
opt_map=''
opt_live_explicit=0
opt_live=1
opt_no_color=0
opt_batch=0
opt_batch_format="text"
opt_verbose=1
opt_variant1=0
opt_variant2=0
opt_variant3=0
opt_allvariants=1
opt_no_sysfs=0
opt_coreos=0
global_critical=0
global_unknown=0
nrpe_vuln=""
echo_cmd=''
__echo()
{
opt="$1"
shift
_msg="$@"
if [ -z "$echo_cmd" ]; then
# find a sane `echo` command
# we'll try to avoid using shell builtins that might not take options
if which echo >/dev/null 2>&1; then
echo_cmd=`which echo`
else
[ -x /bin/echo ] && echo_cmd=/bin/echo
[ -x /system/bin/echo ] && echo_cmd=/system/bin/echo
fi
# still empty ? fallback to builtin
[ -z "$echo_cmd" ] && echo_cmd=echo
fi
if [ "$opt_no_color" = 1 ] ; then
# strip ANSI color codes
_msg=$($echo_cmd -e "$_msg" | sed -r "s/\x1B\[([0-9]{1,2}(;[0-9]{1,2})?)?[m|K]//g")
fi
$echo_cmd $opt -e "$_msg"
}
_echo()
{
if [ $opt_verbose -ge $1 ]; then
shift
__echo '' "$@"
fi
}
_echo_nol()
{
if [ $opt_verbose -ge $1 ]; then
shift
__echo -n "$@"
fi
}
_warn()
{
_echo 0 "\033[31m${@}\033[0m" >&2
}
_info()
{
_echo 1 "$@"
}
_info_nol()
{
_echo_nol 1 "$@"
}
_verbose()
{
_echo 2 "$@"
}
_verbose_nol()
{
_echo_nol 2 "$@"
}
_debug()
{
_echo 3 "\033[34m(debug) $@\033[0m"
}
is_cpu_vulnerable_cached=0
_is_cpu_vulnerable_cached()
{
[ "$1" = 1 ] && return $variant1
[ "$1" = 2 ] && return $variant2
[ "$1" = 3 ] && return $variant3
echo "$0: error: invalid variant '$1' passed to is_cpu_vulnerable()" >&2
exit 255
}
is_cpu_vulnerable()
{
# param: 1, 2 or 3 (variant)
# returns 0 if vulnerable, 1 if not vulnerable
# (note that in shell, a return of 0 is success)
# by default, everything is vulnerable, we work in a "whitelist" logic here.
# usage: is_cpu_vulnerable 2 && do something if vulnerable
if [ "$is_cpu_vulnerable_cached" = 1 ]; then
_is_cpu_vulnerable_cached "$1"
return $?
fi
variant1=''
variant2=''
variant3=''
# we also set a friendly name for the CPU to be used in the script if needed
cpu_friendly_name=$(grep '^model name' /proc/cpuinfo | cut -d: -f2- | head -1)
if grep -q GenuineIntel /proc/cpuinfo; then
# Intel
# Old Atoms are not vulnerable to spectre 2 nor meltdown
# https://security-center.intel.com/advisory.aspx?intelid=INTEL-SA-00088&languageid=en-fr
# model name : Genuine Intel(R) CPU N270 @ 1.60GHz
# model name : Intel(R) Atom(TM) CPU N270 @ 1.60GHz
# model name : Intel(R) Atom(TM) CPU 330 @ 1.60GHz
#
# https://github.com/crozone/SpectrePoC/issues/1 ^F E5200:
# model name : Pentium(R) Dual-Core CPU E5200 @ 2.50GHz
if grep -qE -e '^model name.+ Intel\(R\) (Atom\(TM\) CPU +(S|D|N|230|330)|CPU N[0-9]{3} )' \
-e '^model name.+ Pentium\(R\) Dual-Core[[:space:]]+CPU[[:space:]]+E[0-9]{4}K? ' \
/proc/cpuinfo; then
variant1=vuln
[ -z "$variant2" ] && variant2=immune
[ -z "$variant3" ] && variant3=immune
fi
elif grep -q AuthenticAMD /proc/cpuinfo; then
# AMD revised their statement about variant2 => vulnerable
# https://www.amd.com/en/corporate/speculative-execution
variant1=vuln
variant2=vuln
[ -z "$variant3" ] && variant3=immune
elif grep -qi 'CPU implementer[[:space:]]*:[[:space:]]*0x41' /proc/cpuinfo; then
# ARM
# reference: https://developer.arm.com/support/security-update
# some devices (phones or other) have several ARMs and as such different part numbers,
# an example is "bigLITTLE". we shouldn't rely on the first CPU only, so we check the whole list
cpupart_list=$(awk '/CPU part/ {print $4}' /proc/cpuinfo)
cpuarch_list=$(awk '/CPU architecture/ {print $3}' /proc/cpuinfo)
i=0
for cpupart in $cpupart_list
do
i=$(( i + 1 ))
cpuarch=$(echo $cpuarch_list | awk '{ print $'$i' }')
_debug "checking cpu$i: <$cpupart> <$cpuarch>"
# some kernels report AArch64 instead of 8
[ "$cpuarch" = "AArch64" ] && cpuarch=8
if [ -n "$cpupart" -a -n "$cpuarch" ]; then
cpu_friendly_name="ARM v$cpuarch model $cpupart"
# Cortex-R7 and Cortex-R8 are real-time and only used in medical devices or such
# I can't find their CPU part number, but it's probably not that useful anyway
# model R7 R8 A9 A15 A17 A57 A72 A73 A75
# part ? ? 0xc09 0xc0f 0xc0e 0xd07 0xd08 0xd09 0xd0a
# arch 7? 7? 7 7 7 8 8 8 8
#
# variant 1 & variant 2
if [ "$cpuarch" = 7 ] && echo "$cpupart" | grep -Eq '^0x(c09|c0f|c0e)$'; then
# armv7 vulnerable chips
_debug "checking cpu$i: this armv7 vulnerable to spectre 1 & 2"
variant1=vuln
variant2=vuln
elif [ "$cpuarch" = 8 ] && echo "$cpupart" | grep -Eq '^0x(d07|d08|d09|d0a)$'; then
# armv8 vulnerable chips
_debug "checking cpu$i: this armv8 vulnerable to spectre 1 & 2"
variant1=vuln
variant2=vuln
else
_debug "checking cpu$i: this arm non vulnerable to 1 & 2"
# others are not vulnerable
[ -z "$variant1" ] && variant1=immune
[ -z "$variant2" ] && variant2=immune
fi
# for variant3, only A75 is vulnerable
if [ "$cpuarch" = 8 -a "$cpupart" = 0xd0a ]; then
_debug "checking cpu$i: arm A75 vulnerable to meltdown"
variant3=vuln
else
_debug "checking cpu$i: this arm non vulnerable to meltdown"
[ -z "$variant3" ] && variant3=immune
fi
fi
_debug "is_cpu_vulnerable: for cpu$i and so far, we have <$variant1> <$variant2> <$variant3>"
done
fi
_debug "is_cpu_vulnerable: temp results are <$variant1> <$variant2> <$variant3>"
# if at least one of the cpu is vulnerable, then the system is vulnerable
[ "$variant1" = "immune" ] && variant1=1 || variant1=0
[ "$variant2" = "immune" ] && variant2=1 || variant2=0
[ "$variant3" = "immune" ] && variant3=1 || variant3=0
_debug "is_cpu_vulnerable: final results are <$variant1> <$variant2> <$variant3>"
is_cpu_vulnerable_cached=1
_is_cpu_vulnerable_cached "$1"
return $?
}
show_header()
{
_info "\033[1;34mSpectre and Meltdown mitigation detection tool v$VERSION\033[0m"
_info
}
parse_opt_file()
{
# parse_opt_file option_name option_value
option_name="$1"
option_value="$2"
if [ -z "$option_value" ]; then
show_header
show_usage
echo "$0: error: --$option_name expects one parameter (a file)" >&2
exit 1
elif [ ! -e "$option_value" ]; then
show_header
echo "$0: error: couldn't find file $option_value" >&2
exit 1
elif [ ! -f "$option_value" ]; then
show_header
echo "$0: error: $option_value is not a file" >&2
exit 1
elif [ ! -r "$option_value" ]; then
show_header
echo "$0: error: couldn't read $option_value (are you root?)" >&2
exit 1
fi
echo "$option_value"
exit 0
}
while [ -n "$1" ]; do
if [ "$1" = "--kernel" ]; then
opt_kernel=$(parse_opt_file kernel "$2")
[ $? -ne 0 ] && exit 255
shift 2
opt_live=0
elif [ "$1" = "--config" ]; then
opt_config=$(parse_opt_file config "$2")
[ $? -ne 0 ] && exit 255
shift 2
opt_live=0
elif [ "$1" = "--map" ]; then
opt_map=$(parse_opt_file map "$2")
[ $? -ne 0 ] && exit 255
shift 2
opt_live=0
elif [ "$1" = "--live" ]; then
opt_live_explicit=1
shift
elif [ "$1" = "--no-color" ]; then
opt_no_color=1
shift
elif [ "$1" = "--no-sysfs" ]; then
opt_no_sysfs=1
shift
elif [ "$1" = "--coreos" ]; then
opt_coreos=1
shift
elif [ "$1" = "--coreos-within-toolbox" ]; then
# don't use directly: used internally by --coreos
opt_coreos=0
shift
elif [ "$1" = "--batch" ]; then
opt_batch=1
opt_verbose=0
shift
case "$1" in
text|nrpe|json) opt_batch_format="$1"; shift;;
--*) ;; # allow subsequent flags
'') ;; # allow nothing at all
*)
echo "$0: error: unknown batch format '$1'" >&2
echo "$0: error: --batch expects a format from: text, nrpe, json" >&2
exit 255
;;
esac
elif [ "$1" = "-v" -o "$1" = "--verbose" ]; then
opt_verbose=$(expr $opt_verbose + 1)
shift
elif [ "$1" = "--variant" ]; then
if [ -z "$2" ]; then
echo "$0: error: option --variant expects a parameter (1, 2 or 3)" >&2
exit 255
fi
case "$2" in
1) opt_variant1=1; opt_allvariants=0;;
2) opt_variant2=1; opt_allvariants=0;;
3) opt_variant3=1; opt_allvariants=0;;
*)
echo "$0: error: invalid parameter '$2' for --variant, expected either 1, 2 or 3" >&2;
exit 255
;;
esac
shift 2
elif [ "$1" = "-h" -o "$1" = "--help" ]; then
show_header
show_usage
exit 0
elif [ "$1" = "--version" ]; then
opt_no_color=1
show_header
exit 0
elif [ "$1" = "--disclaimer" ]; then
show_header
show_disclaimer
exit 0
else
show_header
show_usage
echo "$0: error: unknown option '$1'"
exit 255
fi
done
show_header
# print status function
pstatus()
{
if [ "$opt_no_color" = 1 ]; then
_info_nol "$2"
else
case "$1" in
red) col="\033[41m\033[30m";;
green) col="\033[42m\033[30m";;
yellow) col="\033[43m\033[30m";;
blue) col="\033[44m\033[30m";;
*) col="";;
esac
_info_nol "$col $2 \033[0m"
fi
[ -n "$3" ] && _info_nol " ($3)"
_info
}
# Print the final status of a vulnerability (incl. batch mode)
# Arguments are: CVE UNK/OK/VULN description
pvulnstatus()
{
if [ "$opt_batch" = 1 ]; then
case "$opt_batch_format" in
text) _echo 0 "$1: $2 ($3)";;
json)
case "$1" in
CVE-2017-5753) aka="SPECTRE VARIANT 1";;
CVE-2017-5715) aka="SPECTRE VARIANT 2";;
CVE-2017-5754) aka="MELTDOWN";;
esac
case "$2" in
UNK) is_vuln="null";;
VULN) is_vuln="true";;
OK) is_vuln="false";;
esac
json_output="${json_output:-[}{\"NAME\":\""$aka"\",\"CVE\":\""$1"\",\"VULNERABLE\":$is_vuln,\"INFOS\":\""$3"\"},"
;;
nrpe) [ "$2" = VULN ] && nrpe_vuln="$nrpe_vuln $1";;
esac
fi
# always fill global_* vars because we use that do decide the program exit code
case "$2" in
UNK) global_unknown="1";;
VULN) global_critical="1";;
esac
# display info if we're not in quiet/batch mode
vulnstatus="$2"
shift 2
_info_nol "> \033[46m\033[30mSTATUS:\033[0m "
case "$vulnstatus" in
UNK) pstatus yellow 'UNKNOWN' "$@";;
VULN) pstatus red 'VULNERABLE' "$@";;
OK) pstatus green 'NOT VULNERABLE' "$@";;
esac
}
# The 3 below functions are taken from the extract-linux script, available here:
# https://github.com/torvalds/linux/blob/master/scripts/extract-vmlinux
# The functions have been modified for better integration to this script
# The original header of the file has been retained below
# ----------------------------------------------------------------------
# extract-vmlinux - Extract uncompressed vmlinux from a kernel image
#
# Inspired from extract-ikconfig
# (c) 2009,2010 Dick Streefland <dick@streefland.net>
#
# (c) 2011 Corentin Chary <corentin.chary@gmail.com>
#
# Licensed under the GNU General Public License, version 2 (GPLv2).
# ----------------------------------------------------------------------
vmlinux=''
vmlinux_err=''
check_vmlinux()
{
readelf -h "$1" >/dev/null 2>&1 && return 0
return 1
}
try_decompress()
{
# The obscure use of the "tr" filter is to work around older versions of
# "grep" that report the byte offset of the line instead of the pattern.
# Try to find the header ($1) and decompress from here
for pos in `tr "$1\n$2" "\n$2=" < "$6" | grep -abo "^$2"`
do
_debug "try_decompress: magic for $3 found at offset $pos"
if ! which "$3" >/dev/null 2>&1; then
vmlinux_err="missing '$3' tool, please install it, usually it's in the '$5' package"
return 0
fi
pos=${pos%%:*}
tail -c+$pos "$6" 2>/dev/null | $3 $4 > $vmlinuxtmp 2>/dev/null
if check_vmlinux "$vmlinuxtmp"; then
vmlinux="$vmlinuxtmp"
_debug "try_decompress: decompressed with $3 successfully!"
return 0
else
_debug "try_decompress: decompression with $3 did not work"
fi
done
return 1
}
extract_vmlinux()
{
[ -n "$1" ] || return 1
# Prepare temp files:
vmlinuxtmp="$(mktemp /tmp/vmlinux-XXXXXX)"
trap "rm -f $vmlinuxtmp" EXIT
# Initial attempt for uncompressed images or objects:
if check_vmlinux "$1"; then
cat "$1" > "$vmlinuxtmp"
vmlinux=$vmlinuxtmp
return 0
fi
# That didn't work, so retry after decompression.
try_decompress '\037\213\010' xy gunzip '' gunzip "$1" && return 0
try_decompress '\3757zXZ\000' abcde unxz '' xz-utils "$1" && return 0
try_decompress 'BZh' xy bunzip2 '' bzip2 "$1" && return 0
try_decompress '\135\0\0\0' xxx unlzma '' xz-utils "$1" && return 0
try_decompress '\211\114\132' xy 'lzop' '-d' lzop "$1" && return 0
try_decompress '\002\041\114\030' xyy 'lz4' '-d -l' liblz4-tool "$1" && return 0
return 1
}
# end of extract-vmlinux functions
mount_debugfs()
{
if [ ! -e /sys/kernel/debug/sched_features ]; then
# try to mount the debugfs hierarchy ourselves and remember it to umount afterwards
mount -t debugfs debugfs /sys/kernel/debug 2>/dev/null && mounted_debugfs=1
fi
}
umount_debugfs()
{
if [ "$mounted_debugfs" = 1 ]; then
# umount debugfs if we did mount it ourselves
umount /sys/kernel/debug
fi
}
load_msr()
{
modprobe msr 2>/dev/null && insmod_msr=1
_debug "attempted to load module msr, insmod_msr=$insmod_msr"
}
unload_msr()
{
if [ "$insmod_msr" = 1 ]; then
# if we used modprobe ourselves, rmmod the module
rmmod msr 2>/dev/null
_debug "attempted to unload module msr, ret=$?"
fi
}
load_cpuid()
{
modprobe cpuid 2>/dev/null && insmod_cpuid=1
_debug "attempted to load module cpuid, insmod_cpuid=$insmod_cpuid"
}
unload_cpuid()
{
if [ "$insmod_cpuid" = 1 ]; then
# if we used modprobe ourselves, rmmod the module
rmmod cpuid 2>/dev/null
_debug "attempted to unload module cpuid, ret=$?"
fi
}
dmesg_grep()
{
# grep for something in dmesg, ensuring that the dmesg buffer
# has not been truncated
dmesg_grepped=''
if ! dmesg | grep -qE '(^|\] )Linux version [0-9]'; then
# dmesg truncated
return 2
fi
dmesg_grepped=$(dmesg | grep -E "$1" | head -1)
# not found:
[ -z "$dmesg_grepped" ] && return 1
# found, output is in $dmesg_grepped
return 0
}
is_coreos()
{
which coreos-install >/dev/null 2>&1 && which toolbox >/dev/null 2>&1 && return 0
return 1
}
# check for mode selection inconsistency
if [ "$opt_live_explicit" = 1 ]; then
if [ -n "$opt_kernel" -o -n "$opt_config" -o -n "$opt_map" ]; then
show_usage
echo "$0: error: incompatible modes specified, use either --live or --kernel/--config/--map" >&2
exit 255
fi
fi
# coreos mode
if [ "$opt_coreos" = 1 ]; then
if ! is_coreos; then
_warn "CoreOS mode asked, but we're not under CoreOS!"
exit 255
fi
_warn "CoreOS mode, starting an ephemeral toolbox to launch the script"
load_msr
load_cpuid
mount_debugfs
toolbox --ephemeral --bind-ro /dev/cpu:/dev/cpu -- sh -c "dnf install -y binutils which && /media/root$PWD/$0 $@ --coreos-within-toolbox"
exitcode=$?
mount_debugfs
unload_cpuid
unload_msr
exit $exitcode
else
if is_coreos; then
_warn "You seem to be running CoreOS, you might want to use the --coreos option for better results"
_warn
fi
fi
# root check (only for live mode, for offline mode, we already checked if we could read the files)
if [ "$opt_live" = 1 ]; then
if [ "$(id -u)" -ne 0 ]; then
_warn "Note that you should launch this script with root privileges to get accurate information."
_warn "We'll proceed but you might see permission denied errors."
_warn "To run it as root, you can try the following command: sudo $0"
_warn
fi
_info "Checking for vulnerabilities against running kernel \033[35m"$(uname -s) $(uname -r) $(uname -v) $(uname -m)"\033[0m"
# call is_cpu_vulnerable to fill the cpu_friendly_name var
is_cpu_vulnerable 1
_info "CPU is \033[35m$cpu_friendly_name\033[0m"
# try to find the image of the current running kernel
# first, look for the BOOT_IMAGE hint in the kernel cmdline
if [ -r /proc/cmdline ] && grep -q 'BOOT_IMAGE=' /proc/cmdline; then
opt_kernel=$(grep -Eo 'BOOT_IMAGE=[^ ]+' /proc/cmdline | cut -d= -f2)
_debug "found opt_kernel=$opt_kernel in /proc/cmdline"
# if we have a dedicated /boot partition, our bootloader might have just called it /
# so try to prepend /boot and see if we find anything
[ -e "/boot/$opt_kernel" ] && opt_kernel="/boot/$opt_kernel"
# special case for CoreOS if we're inside the toolbox
[ -e "/media/root/boot/$opt_kernel" ] && opt_kernel="/media/root/boot/$opt_kernel"
_debug "opt_kernel is now $opt_kernel"
# else, the full path is already there (most probably /boot/something)
fi
# if we didn't find a kernel, default to guessing
if [ ! -e "$opt_kernel" ]; then
# Fedora:
[ -e /lib/modules/$(uname -r)/vmlinuz ] && opt_kernel=/lib/modules/$(uname -r)/vmlinuz
# Slackare:
[ -e /boot/vmlinuz ] && opt_kernel=/boot/vmlinuz
# Arch:
[ -e /boot/vmlinuz-linux ] && opt_kernel=/boot/vmlinuz-linux
# Linux-Libre:
[ -e /boot/vmlinuz-linux-libre ] && opt_kernel=/boot/vmlinuz-linux-libre
# generic:
[ -e /boot/vmlinuz-$(uname -r) ] && opt_kernel=/boot/vmlinuz-$(uname -r)
[ -e /boot/kernel-$( uname -r) ] && opt_kernel=/boot/kernel-$( uname -r)
[ -e /boot/bzImage-$(uname -r) ] && opt_kernel=/boot/bzImage-$(uname -r)
# Gentoo:
[ -e /boot/kernel-genkernel-$(uname -m)-$(uname -r) ] && opt_kernel=/boot/kernel-genkernel-$(uname -m)-$(uname -r)
# NixOS:
[ -e /run/booted-system/kernel ] && opt_kernel=/run/booted-system/kernel
fi
# system.map
if [ -e /proc/kallsyms ] ; then
opt_map="/proc/kallsyms"
elif [ -e /lib/modules/$(uname -r)/System.map ] ; then
opt_map=/lib/modules/$(uname -r)/System.map
elif [ -e /boot/System.map-$(uname -r) ] ; then
opt_map=/boot/System.map-$(uname -r)
fi
# config
if [ -e /proc/config.gz ] ; then
dumped_config="$(mktemp /tmp/config-XXXXXX)"
gunzip -c /proc/config.gz > $dumped_config
# dumped_config will be deleted at the end of the script
opt_config=$dumped_config
elif [ -e /lib/modules/$(uname -r)/config ]; then
opt_config=/lib/modules/$(uname -r)/config
elif [ -e /boot/config-$(uname -r) ]; then
opt_config=/boot/config-$(uname -r)
fi
else
_info "Checking for vulnerabilities against specified kernel"
fi
if [ -n "$opt_kernel" ]; then
_verbose "Will use vmlinux image \033[35m$opt_kernel\033[0m"
else
_verbose "Will use no vmlinux image (accuracy might be reduced)"
bad_accuracy=1
fi
if [ -n "$opt_config" ] && ! grep -q '^CONFIG_' "$opt_config"; then
# given file is invalid!
_warn "The kernel config file seems invalid, was expecting a plain-text file, ignoring it!"
opt_config=''
fi
if [ -n "$dumped_config" ] && [ -n "$opt_config" ]; then
_verbose "Will use kconfig \033[35m/proc/config.gz (decompressed)\033[0m"
elif [ -n "$opt_config" ]; then
_verbose "Will use kconfig \033[35m$opt_config\033[0m"
else
_verbose "Will use no kconfig (accuracy might be reduced)"
bad_accuracy=1
fi
if [ -n "$opt_map" ]; then
_verbose "Will use System.map file \033[35m$opt_map\033[0m"
else
_verbose "Will use no System.map file (accuracy might be reduced)"
bad_accuracy=1
fi
if [ "$bad_accuracy" = 1 ]; then
_info "We're missing some kernel info (see -v), accuracy might be reduced"
fi
if [ -e "$opt_kernel" ]; then
if ! which readelf >/dev/null 2>&1; then
_debug "readelf not found"
vmlinux_err="missing 'readelf' tool, please install it, usually it's in the 'binutils' package"
else
extract_vmlinux "$opt_kernel"
fi
else
_debug "no opt_kernel defined"
vmlinux_err="couldn't find your kernel image in /boot, if you used netboot, this is normal"
fi
if [ -z "$vmlinux" -o ! -r "$vmlinux" ]; then
[ -z "$vmlinux_err" ] && vmlinux_err="couldn't extract your kernel from $opt_kernel"
fi
_info
# end of header stuff
# now we define some util functions and the check_*() funcs, as
# the user can choose to execute only some of those
sys_interface_check()
{
[ "$opt_live" = 1 -a "$opt_no_sysfs" = 0 -a -r "$1" ] || return 1
_info_nol "* Checking whether we're safe according to the /sys interface: "
if grep -qi '^not affected' "$1"; then
# Not affected
status=OK
pstatus green YES "kernel confirms that your CPU is unaffected"
elif grep -qi '^mitigation' "$1"; then
# Mitigation: PTI
status=OK
pstatus green YES "kernel confirms that the mitigation is active"
elif grep -qi '^vulnerable' "$1"; then
# Vulnerable
status=VULN
pstatus red NO "kernel confirms your system is vulnerable"
else
status=UNK
pstatus yellow UNKNOWN "unknown value reported by kernel"
fi
msg=$(cat "$1")
_debug "sys_interface_check: $1=$msg"
return 0
}
###################
# SPECTRE VARIANT 1
check_variant1()
{
_info "\033[1;34mCVE-2017-5753 [bounds check bypass] aka 'Spectre Variant 1'\033[0m"
status=UNK
sys_interface_available=0
msg=''
if sys_interface_check "/sys/devices/system/cpu/vulnerabilities/spectre_v1"; then
# this kernel has the /sys interface, trust it over everything
sys_interface_available=1
else
# no /sys interface (or offline mode), fallback to our own ways
_info_nol "* Checking count of LFENCE opcodes in kernel: "
if [ -n "$vmlinux_err" ]; then
msg="couldn't check ($vmlinux_err)"
status=UNK
pstatus yellow UNKNOWN
else
if ! which objdump >/dev/null 2>&1; then
msg="missing 'objdump' tool, please install it, usually it's in the binutils package"
status=UNK
pstatus yellow UNKNOWN
else
# here we disassemble the kernel and count the number of occurrences of the LFENCE opcode
# in non-patched kernels, this has been empirically determined as being around 40-50
# in patched kernels, this is more around 70-80, sometimes way higher (100+)
# v0.13: 68 found in a 3.10.23-xxxx-std-ipv6-64 (with lots of modules compiled-in directly), which doesn't have the LFENCE patches,
# so let's push the threshold to 70.
nb_lfence=$(objdump -d "$vmlinux" | grep -wc lfence)
if [ "$nb_lfence" -lt 70 ]; then
msg="only $nb_lfence opcodes found, should be >= 70, heuristic to be improved when official patches become available"
status=VULN
pstatus red NO
else
msg="$nb_lfence opcodes found, which is >= 70, heuristic to be improved when official patches become available"
status=OK
pstatus green YES
fi
fi
fi
fi
# if we have the /sys interface, don't even check is_cpu_vulnerable ourselves, the kernel already does it
if [ "$sys_interface_available" = 0 ] && ! is_cpu_vulnerable 1; then
# override status & msg in case CPU is not vulnerable after all
msg="your CPU vendor reported your CPU model as not vulnerable"
status=OK
fi
# report status
pvulnstatus CVE-2017-5753 "$status" "$msg"
}
###################
# SPECTRE VARIANT 2
check_variant2()
{
_info "\033[1;34mCVE-2017-5715 [branch target injection] aka 'Spectre Variant 2'\033[0m"
status=UNK
sys_interface_available=0
msg=''
if sys_interface_check "/sys/devices/system/cpu/vulnerabilities/spectre_v2"; then
# this kernel has the /sys interface, trust it over everything
sys_interface_available=1
else
_info "* Mitigation 1"
_info "* Hardware (CPU microcode) support for mitigation"
_info_nol "* The SPEC_CTRL MSR is available: "
if [ ! -e /dev/cpu/0/msr ]; then
# try to load the module ourselves (and remember it so we can rmmod it afterwards)
load_msr
fi
if [ ! -e /dev/cpu/0/msr ]; then
pstatus yellow UNKNOWN "couldn't read /dev/cpu/0/msr, is msr support enabled in your kernel?"
else
# the new MSR 'SPEC_CTRL' is at offset 0x48
# here we use dd, it's the same as using 'rdmsr 0x48' but without needing the rdmsr tool
# if we get a read error, the MSR is not there
dd if=/dev/cpu/0/msr of=/dev/null bs=8 count=1 skip=9 2>/dev/null
if [ $? -eq 0 ]; then
pstatus green YES
else
pstatus red NO
fi
fi
unload_msr
# CPUID test
_info_nol "* The SPEC_CTRL CPUID feature bit is set: "
if [ ! -e /dev/cpu/0/cpuid ]; then
# try to load the module ourselves (and remember it so we can rmmod it afterwards)
load_cpuid
fi
if [ ! -e /dev/cpu/0/cpuid ]; then
pstatus yellow UNKNOWN "couldn't read /dev/cpu/0/cpuidr, is cpuid support enabled in your kernel?"
else
# from kernel src: { X86_FEATURE_SPEC_CTRL, CPUID_EDX,26, 0x00000007, 0 },
if [ "$opt_verbose" -ge 3 ]; then
dd if=/dev/cpu/0/cpuid bs=16 skip=7 iflag=skip_bytes count=1 >/dev/null 2>/dev/null
_debug "cpuid: reading leaf7 of cpuid on cpu0, ret=$?"
_debug "cpuid: leaf7 eax-ebx-ecd-edx: "$(dd if=/dev/cpu/0/cpuid bs=16 skip=7 iflag=skip_bytes count=1 2>/dev/null | od -x -A n)
_debug "cpuid: leaf7 edx higher-half is: "$(dd if=/dev/cpu/0/cpuid bs=16 skip=7 iflag=skip_bytes count=1 2>/dev/null | dd bs=1 skip=15 count=1 2>/dev/null | od -x -A n)
fi
# getting high byte of edx on leaf7 of cpuinfo in decimal
edx_hb=$(dd if=/dev/cpu/0/cpuid bs=16 skip=7 iflag=skip_bytes count=1 2>/dev/null | dd bs=1 skip=15 count=1 2>/dev/null | od -t u -A n | awk '{print $1}')
_debug "cpuid: leaf7 edx higher byte: $edx_hb (decimal)"
edx_bit26=$(( edx_hb & 8 ))
_debug "cpuid: edx_bit26=$edx_bit26"
if [ "$edx_bit26" -eq 8 ]; then
pstatus green YES
else
pstatus red NO
fi
fi
unload_cpuid
# hardware support according to kernel
if [ "$opt_verbose" -ge 2 ]; then
_verbose_nol "* The kernel has set the spec_ctrl flag in cpuinfo: "
if [ "$opt_live" = 1 ]; then
if grep ^flags /proc/cpuinfo | grep -qw spec_ctrl; then
pstatus green YES
else
pstatus red NO
fi
else
pstatus blue N/A "not testable in offline mode"
fi
fi
_info_nol "* Kernel support for IBRS: "
ibrs_can_tell=0
if [ "$opt_live" = 1 ]; then
ibrs_can_tell=1
mount_debugfs
for ibrs_file in \
/sys/kernel/debug/ibrs_enabled \
/sys/kernel/debug/x86/ibrs_enabled \
/proc/sys/kernel/ibrs_enabled; do
if [ -e "$ibrs_file" ]; then
# if the file is there, we have IBRS compiled-in
# /sys/kernel/debug/ibrs_enabled: vanilla
# /sys/kernel/debug/x86/ibrs_enabled: RedHat (see https://access.redhat.com/articles/3311301)
# /proc/sys/kernel/ibrs_enabled: OpenSUSE tumbleweed
pstatus green YES
ibrs_supported=1
ibrs_enabled=$(cat "$ibrs_file" 2>/dev/null)
_debug "ibrs: found $ibrs_file=$ibrs_enabled"
break
else
_debug "ibrs: file $ibrs_file doesn't exist"
fi
done
# on some newer kernels, the spec_ctrl_ibrs flag in /proc/cpuinfo
# is set when ibrs has been administratively enabled (usually from cmdline)
# which in that case means ibrs is supported *and* enabled for kernel & user
# as per the ibrs patch series v3
if [ "$ibrs_supported" = 0 ]; then
if grep ^flags /proc/cpuinfo | grep -qw spec_ctrl_ibrs; then
_debug "ibrs: found spec_ctrl_ibrs flag in /proc/cpuinfo"
ibrs_supported=1
# enabled=2 -> kernel & user
ibrs_enabled=2
fi
fi
fi
if [ "$ibrs_supported" != 1 -a -n "$opt_map" ]; then
ibrs_can_tell=1
if grep -q spec_ctrl "$opt_map"; then
pstatus green YES
ibrs_supported=1
_debug "ibrs: found '*spec_ctrl*' symbol in $opt_map"
fi
fi
if [ "$ibrs_supported" != 1 ]; then
if [ "$ibrs_can_tell" = 1 ]; then
pstatus red NO
else
# if we're in offline mode without System.map, we can't really know
pstatus yellow UNKNOWN "in offline mode, we need System.map to be able to tell"
fi
fi
_info_nol "* IBRS enabled for Kernel space: "
if [ "$opt_live" = 1 ]; then
# 0 means disabled
# 1 is enabled only for kernel space
# 2 is enabled for kernel and user space
case "$ibrs_enabled" in
"") [ "$ibrs_supported" = 1 ] && pstatus yellow UNKNOWN || pstatus red NO;;
0) pstatus red NO;;
1 | 2) pstatus green YES;;
*) pstatus yellow UNKNOWN;;
esac
else
pstatus blue N/A "not testable in offline mode"
fi
_info_nol "* IBRS enabled for User space: "
if [ "$opt_live" = 1 ]; then
case "$ibrs_enabled" in
"") [ "$ibrs_supported" = 1 ] && pstatus yellow UNKNOWN || pstatus red NO;;
0 | 1) pstatus red NO;;
2) pstatus green YES;;
*) pstatus yellow UNKNOWN;;
esac
else
pstatus blue N/A "not testable in offline mode"
fi
_info "* Mitigation 2"
_info_nol "* Kernel compiled with retpoline option: "
# We check the RETPOLINE kernel options
if [ -r "$opt_config" ]; then
if grep -q '^CONFIG_RETPOLINE=y' "$opt_config"; then
pstatus green YES
retpoline=1
_debug "retpoline: found "$(grep '^CONFIG_RETPOLINE' "$opt_config")" in $opt_config"
else
pstatus red NO
fi
else
pstatus yellow UNKNOWN "couldn't read your kernel configuration"
fi
_info_nol "* Kernel compiled with a retpoline-aware compiler: "
# Now check if the compiler used to compile the kernel knows how to insert retpolines in generated asm
# For gcc, this is -mindirect-branch=thunk-extern (detected by the kernel makefiles)
# See gcc commit https://github.com/hjl-tools/gcc/commit/23b517d4a67c02d3ef80b6109218f2aadad7bd79
# In latest retpoline LKML patches, the noretpoline_setup symbol exists only if CONFIG_RETPOLINE is set
# *AND* if the compiler is retpoline-compliant, so look for that symbol
if [ -n "$opt_map" ]; then
# look for the symbol
if grep -qw noretpoline_setup "$opt_map"; then
retpoline_compiler=1
pstatus green YES "noretpoline_setup symbol found in System.map"
else
pstatus red NO
fi
elif [ -n "$vmlinux" ]; then
# look for the symbol
if which nm >/dev/null 2>&1; then
# the proper way: use nm and look for the symbol
if nm "$vmlinux" 2>/dev/null | grep -qw 'noretpoline_setup'; then
retpoline_compiler=1
pstatus green YES "noretpoline_setup found in vmlinux symbols"
else
pstatus red NO
fi
elif grep -q noretpoline_setup "$vmlinux"; then
# if we don't have nm, nevermind, the symbol name is long enough to not have
# any false positive using good old grep directly on the binary
retpoline_compiler=1
pstatus green YES "noretpoline_setup found in vmlinux"
else
pstatus red NO
fi
else
pstatus yellow UNKNOWN "couldn't find your kernel image or System.map"
fi
fi
# if we have the /sys interface, don't even check is_cpu_vulnerable ourselves, the kernel already does it
if [ "$sys_interface_available" = 0 ] && ! is_cpu_vulnerable 2; then
# override status & msg in case CPU is not vulnerable after all
pvulnstatus CVE-2017-5715 OK "your CPU vendor reported your CPU model as not vulnerable"
elif [ -z "$msg" ]; then
# if msg is empty, sysfs check didn't fill it, rely on our own test
if [ "$retpoline" = 1 -a "$retpoline_compiler" = 1 ]; then
pvulnstatus CVE-2017-5715 OK "retpoline mitigate the vulnerability"
elif [ "$opt_live" = 1 ]; then
if [ "$ibrs_enabled" = 1 -o "$ibrs_enabled" = 2 ]; then
pvulnstatus CVE-2017-5715 OK "IBRS mitigates the vulnerability"
else
pvulnstatus CVE-2017-5715 VULN "IBRS hardware + kernel support OR kernel with retpoline are needed to mitigate the vulnerability"
fi
else
if [ "$ibrs_supported" = 1 ]; then
pvulnstatus CVE-2017-5715 OK "offline mode: IBRS will mitigate the vulnerability if enabled at runtime"
elif [ "$ibrs_can_tell" = 1 ]; then
pvulnstatus CVE-2017-5715 VULN "IBRS hardware + kernel support OR kernel with retpoline are needed to mitigate the vulnerability"
else
pvulnstatus CVE-2017-5715 UNK "offline mode: not enough information"
fi
fi
else
pvulnstatus CVE-2017-5715 "$status" "$msg"
fi
}
########################
# MELTDOWN aka VARIANT 3
check_variant3()
{
_info "\033[1;34mCVE-2017-5754 [rogue data cache load] aka 'Meltdown' aka 'Variant 3'\033[0m"
status=UNK
sys_interface_available=0
msg=''
if sys_interface_check "/sys/devices/system/cpu/vulnerabilities/meltdown"; then
# this kernel has the /sys interface, trust it over everything
sys_interface_available=1
else
_info_nol "* Kernel supports Page Table Isolation (PTI): "
kpti_support=0
kpti_can_tell=0
if [ -n "$opt_config" ]; then
kpti_can_tell=1
if grep -Eq '^(CONFIG_PAGE_TABLE_ISOLATION|CONFIG_KAISER)=y' "$opt_config"; then
_debug "kpti_support: found option "$(grep -E '^(CONFIG_PAGE_TABLE_ISOLATION|CONFIG_KAISER)=y' "$opt_config")" in $opt_config"
kpti_support=1
fi
fi
if [ "$kpti_support" = 0 -a -n "$opt_map" ]; then
# it's not an elif: some backports don't have the PTI config but still include the patch
# so we try to find an exported symbol that is part of the PTI patch in System.map
kpti_can_tell=1
if grep -qw kpti_force_enabled "$opt_map"; then
_debug "kpti_support: found kpti_force_enabled in $opt_map"
kpti_support=1
fi
fi
if [ "$kpti_support" = 0 -a -n "$vmlinux" ]; then
# same as above but in case we don't have System.map and only vmlinux, look for the
# nopti option that is part of the patch (kernel command line option)
kpti_can_tell=1
if ! which strings >/dev/null 2>&1; then
pstatus yellow UNKNOWN "missing 'strings' tool, please install it, usually it's in the binutils package"
else
if strings "$vmlinux" | grep -qw nopti; then
_debug "kpti_support: found nopti string in $vmlinux"
kpti_support=1
fi
fi
fi
if [ "$kpti_support" = 1 ]; then
pstatus green YES
elif [ "$kpti_can_tell" = 1 ]; then
pstatus red NO
else
pstatus yellow UNKNOWN "couldn't read your kernel configuration nor System.map file"
fi
mount_debugfs
_info_nol "* PTI enabled and active: "
if [ "$opt_live" = 1 ]; then
dmesg_grep="Kernel/User page tables isolation: enabled"
dmesg_grep="$dmesg_grep|Kernel page table isolation enabled"
dmesg_grep="$dmesg_grep|x86/pti: Unmapping kernel while in userspace"
if grep ^flags /proc/cpuinfo | grep -qw pti; then
# vanilla PTI patch sets the 'pti' flag in cpuinfo
_debug "kpti_enabled: found 'pti' flag in /proc/cpuinfo"
kpti_enabled=1
elif grep ^flags /proc/cpuinfo | grep -qw kaiser; then
# kernel line 4.9 sets the 'kaiser' flag in cpuinfo
_debug "kpti_enabled: found 'kaiser' flag in /proc/cpuinfo"
kpti_enabled=1
elif [ -e /sys/kernel/debug/x86/pti_enabled ]; then
# RedHat Backport creates a dedicated file, see https://access.redhat.com/articles/3311301
kpti_enabled=$(cat /sys/kernel/debug/x86/pti_enabled 2>/dev/null)
_debug "kpti_enabled: file /sys/kernel/debug/x86/pti_enabled exists and says: $kpti_enabled"
fi
if [ -z "$kpti_enabled" ]; then
dmesg_grep "$dmesg_grep"; ret=$?
if [ $ret -eq 0 ]; then
_debug "kpti_enabled: found hint in dmesg: $dmesg_grepped"
kpti_enabled=1
elif [ $ret -eq 2 ]; then
_debug "kpti_enabled: dmesg truncated"
kpti_enabled=-1
fi
fi
if [ -z "$kpti_enabled" ]; then
_debug "kpti_enabled: couldn't find any hint that PTI is enabled"
kpti_enabled=0
fi
if [ "$kpti_enabled" = 1 ]; then
pstatus green YES
elif [ "$kpti_enabled" = -1 ]; then
pstatus yellow UNKNOWN "dmesg truncated, please reboot and relaunch this script"
else
pstatus red NO
fi
else
pstatus blue N/A "can't verify if PTI is enabled in offline mode"
fi
# no security impact but give a hint to the user in verbose mode
# about PCID/INVPCID cpuid features that must be present to avoid
# too big a performance impact with PTI
# refs:
# https://marc.info/?t=151532047900001&r=1&w=2
# https://groups.google.com/forum/m/#!topic/mechanical-sympathy/L9mHTbeQLNU
if [ "$opt_verbose" -ge 2 ]; then
_info "* Performance impact if PTI is enabled"
_info_nol "* CPU supports PCID: "
if grep ^flags /proc/cpuinfo | grep -qw pcid; then
pstatus green YES 'performance degradation with PTI will be limited'
else
pstatus blue NO 'no security impact but performance will be degraded with PTI'
fi
_info_nol "* CPU supports INVPCID: "
if grep ^flags /proc/cpuinfo | grep -qw invpcid; then
pstatus green YES 'performance degradation with PTI will be limited'
else
pstatus blue NO 'no security impact but performance will be degraded with PTI'
fi
fi
if [ "$opt_live" = 1 ]; then
# checking whether we're running under Xen PV 64 bits. If yes, we're not affected by variant3
_info_nol "* Checking if we're running under Xen PV (64 bits): "
if [ "$(uname -m)" = "x86_64" ]; then
# XXX do we have a better way that relying on dmesg?
dmesg_grep 'Booting paravirtualized kernel on Xen$'; ret=$?
if [ $ret -eq 0 ]; then
pstatus green YES 'Xen PV is not vulnerable'
xen_pv=1
elif [ $ret -eq 2 ]; then
pstatus yellow UNKNOWN "dmesg truncated, please reboot and relaunch this script"
else
pstatus blue NO
fi
else
pstatus blue NO
fi
fi
fi
# if we have the /sys interface, don't even check is_cpu_vulnerable ourselves, the kernel already does it
cve='CVE-2017-5754'
if [ "$sys_interface_available" = 0 ] && ! is_cpu_vulnerable 3; then
# override status & msg in case CPU is not vulnerable after all
pvulnstatus $cve OK "your CPU vendor reported your CPU model as not vulnerable"
elif [ -z "$msg" ]; then
# if msg is empty, sysfs check didn't fill it, rely on our own test
if [ "$opt_live" = 1 ]; then
if [ "$kpti_enabled" = 1 ]; then
pvulnstatus $cve OK "PTI mitigates the vulnerability"
elif [ "$xen_pv" = 1 ]; then
pvulnstatus $cve OK "Xen PV 64 bits is not vulnerable"
else
pvulnstatus $cve VULN "PTI is needed to mitigate the vulnerability"
fi
else
if [ "$kpti_support" = 1 ]; then
pvulnstatus $cve OK "offline mode: PTI will mitigate the vulnerability if enabled at runtime"
elif [ "$kpti_can_tell" = 1 ]; then
pvulnstatus $cve VULN "PTI is needed to mitigate the vulnerability"
else
pvulnstatus $cve UNK "offline mode: not enough information"
fi
fi
else
pvulnstatus $cve "$status" "$msg"
fi
}
# now run the checks the user asked for
if [ "$opt_variant1" = 1 -o "$opt_allvariants" = 1 ]; then
check_variant1
_info
fi
if [ "$opt_variant2" = 1 -o "$opt_allvariants" = 1 ]; then
check_variant2
_info
fi
if [ "$opt_variant3" = 1 -o "$opt_allvariants" = 1 ]; then
check_variant3
_info
fi
_info "A false sense of security is worse than no security at all, see --disclaimer"
# this'll umount only if we mounted debugfs ourselves
umount_debugfs
# cleanup the temp decompressed config
[ -n "$dumped_config" ] && [ -f "$dumped_config" ] && rm -f "$dumped_config"
if [ "$opt_batch" = 1 -a "$opt_batch_format" = "nrpe" ]; then
if [ ! -z "$nrpe_vuln" ]; then
echo "Vulnerable:$nrpe_vuln"
else
echo "OK"
fi
fi
if [ "$opt_batch" = 1 -a "$opt_batch_format" = "json" ]; then
_echo 0 ${json_output%?}']'
fi
# exit with the proper exit code
[ "$global_critical" = 1 ] && exit 2 # critical
[ "$global_unknown" = 1 ] && exit 3 # unknown
exit 0 # ok
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