spectre-meltdown-checker/spectre-meltdown-checker.sh

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#! /bin/sh
# Spectre & Meltdown checker
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#
# 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
#
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# Stephane Lesimple
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#
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VERSION=0.31
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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>]
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Modes:
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Two modes are available.
First mode is the "live" mode (default), it does its best to find information about the currently running kernel.
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To run under this mode, just start the script without any option (you can also use --live explicitly)
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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:
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--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
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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...
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--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)
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Return codes:
0 (not vulnerable), 2 (vulnerable), 3 (unknown), 255 (error)
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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
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explicitly stated otherwise in a verifiable public announcement.
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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.
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EOF
}
# parse options
opt_kernel=''
opt_config=''
opt_map=''
opt_live_explicit=0
opt_live=1
opt_no_color=0
opt_batch=0
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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
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global_critical=0
global_unknown=0
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nrpe_vuln=""
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__echo()
{
opt="$1"
shift
_msg="$@"
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if [ "$opt_no_color" = 1 ] ; then
# strip ANSI color codes
_msg=$(/bin/echo -e "$_msg" | sed -r "s/\x1B\[([0-9]{1,2}(;[0-9]{1,2})?)?[m|K]//g")
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fi
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# explicitly call /bin/echo to avoid shell builtins that might not take options
/bin/echo $opt -e "$_msg"
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}
_echo()
{
if [ $opt_verbose -ge $1 ]; then
shift
__echo '' "$@"
fi
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}
_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 "$@"
}
_verbose()
{
_echo 2 "$@"
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}
_verbose_nol()
{
_echo_nol 2 "$@"
}
_debug()
{
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_echo 3 "\033[34m(debug) $@\033[0m"
}
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is_cpu_vulnerable()
{
# param: 1, 2 or 3 (variant)
# returns 0 if vulnerable, 1 if not vulnerable
# (note that in shell, a return of 0 is success)
# by default, everything is vulnerable, we work in a "whitelist" logic here.
# usage: is_cpu_vulnerable 2 && do something if vulnerable
variant1=0
variant2=0
variant3=0
# we also set a friendly name for the CPU to be used in the script if needed
cpu_friendly_name=$(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
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# model name : Intel(R) Atom(TM) CPU N270 @ 1.60GHz
# model name : Intel(R) Atom(TM) CPU 330 @ 1.60GHz
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if grep -qE '^model name.+ Intel\(R\) (Atom\(TM\) CPU +(S|D|N|230|330)|CPU N[0-9]{3} )' /proc/cpuinfo; then
variant2=1
variant3=1
fi
elif grep -q AuthenticAMD /proc/cpuinfo; then
# AMD revised their statement about variant2 => vulnerable
# https://www.amd.com/en/corporate/speculative-execution
variant3=1
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elif grep -qi 'CPU implementer\s*:\s*0x41' /proc/cpuinfo; then
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# ARM
# reference: https://developer.arm.com/support/security-update
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cpupart=$(awk '/CPU part/ {print $4;exit}' /proc/cpuinfo)
cpuarch=$(awk '/CPU architecture/ {print $3;exit}' /proc/cpuinfo)
# some kernels report AArch64 instead of 8
[ "$cpuarch" = "AArch64" ] && cpuarch=8
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if [ -n "$cpupart" -a -n "$cpuarch" ]; then
cpu_friendly_name="ARM v$cpuarch model $cpupart"
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# Cortex-R7 and Cortex-R8 are real-time and only used in medical devices or such
# I can't find their CPU part number, but it's probably not that useful anyway
# model R7 R8 A9 A15 A17 A57 A72 A73 A75
# part ? ? 0xc09 0xc0f 0xc0e 0xd07 0xd08 0xd09 0xd0a
# arch 7? 7? 7 7 7 8 8 8 8
if [ "$cpuarch" = 7 ] && echo "$cpupart" | grep -Eq '^0x(c09|c0f|c0e)$'; then
# armv7 vulnerable chips
:
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elif [ "$cpuarch" = 8 ] && echo "$cpupart" | grep -Eq '^0x(d07|d08|d09|d0a)$'; then
# armv8 vulnerable chips
:
else
# others are not vulnerable
variant1=1
variant2=1
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fi
# for variant3, only A75 is vulnerable
if ! [ "$cpuarch" = 8 -a "$cpupart" = 0xd0a ]; then
variant3=1
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fi
fi
fi
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[ "$1" = 1 ] && return $variant1
[ "$1" = 2 ] && return $variant2
[ "$1" = 3 ] && return $variant3
echo "$0: error: invalid variant '$1' passed to is_cpu_vulnerable()" >&2
exit 255
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}
show_header()
{
_info "\033[1;34mSpectre and Meltdown mitigation detection tool v$VERSION\033[0m"
_info
}
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parse_opt_file()
{
# parse_opt_file option_name option_value
option_name="$1"
option_value="$2"
if [ -z "$option_value" ]; then
show_header
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show_usage
echo "$0: error: --$option_name expects one parameter (a file)" >&2
exit 1
elif [ ! -e "$option_value" ]; then
show_header
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echo "$0: error: couldn't find file $option_value" >&2
exit 1
elif [ ! -f "$option_value" ]; then
show_header
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echo "$0: error: $option_value is not a file" >&2
exit 1
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elif [ ! -r "$option_value" ]; then
show_header
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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
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shift 2
opt_live=0
elif [ "$1" = "--config" ]; then
opt_config=$(parse_opt_file config "$2")
[ $? -ne 0 ] && exit 255
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shift 2
opt_live=0
elif [ "$1" = "--map" ]; then
opt_map=$(parse_opt_file map "$2")
[ $? -ne 0 ] && exit 255
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shift 2
opt_live=0
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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
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case "$1" in
text|nrpe|json) opt_batch_format="$1"; shift;;
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--*) ;; # 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
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;;
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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
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elif [ "$1" = "-h" -o "$1" = "--help" ]; then
show_header
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show_usage
exit 0
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elif [ "$1" = "--version" ]; then
opt_no_color=1
show_header
exit 0
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elif [ "$1" = "--disclaimer" ]; then
show_header
show_disclaimer
exit 0
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else
show_header
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show_usage
echo "$0: error: unknown option '$1'"
exit 255
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fi
done
show_header
# print status function
pstatus()
{
if [ "$opt_no_color" = 1 ]; then
_info_nol "$2"
else
case "$1" in
red) col="\033[101m\033[30m";;
green) col="\033[102m\033[30m";;
yellow) col="\033[103m\033[30m";;
blue) col="\033[104m\033[30m";;
*) col="";;
esac
_info_nol "$col $2 \033[0m"
fi
[ -n "$3" ] && _info_nol " ($3)"
_info
}
# Print the final status of a vulnerability (incl. batch mode)
# Arguments are: CVE UNK/OK/VULN description
pvulnstatus()
{
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if [ "$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";;
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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
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vulnstatus="$2"
shift 2
_info_nol "> \033[46m\033[30mSTATUS:\033[0m "
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case "$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 1
return 0
}
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
}
is_coreos()
{
which coreos-install >/dev/null 2>&1 && which toolbox >/dev/null 2>&1 && return 0
return 1
}
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# 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 "$0: error: incompatible modes specified, use either --live or --kernel/--config/--map" >&2
exit 255
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fi
fi
# coreos mode
if [ "$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 $exitcode
else
if is_coreos; then
_warn "You seem to be running CoreOS, you might want to use the --coreos option for better results"
_warn
fi
fi
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# root check (only for live mode, for offline mode, we already checked if we could read the files)
if [ "$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 $0"
_warn
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fi
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_info "Checking for vulnerabilities against running kernel \033[35m"$(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"
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# 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
[ -e /lib/modules/$(uname -r)/vmlinuz ] && opt_kernel=/lib/modules/$(uname -r)/vmlinuz
[ -e /boot/vmlinuz ] && opt_kernel=/boot/vmlinuz
[ -e /boot/vmlinuz-linux ] && opt_kernel=/boot/vmlinuz-linux
[ -e /boot/vmlinuz-linux-libre ] && opt_kernel=/boot/vmlinuz-linux-libre
[ -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)
[ -e /boot/kernel-genkernel-$(uname -m)-$(uname -r) ] && opt_kernel=/boot/kernel-genkernel-$(uname -m)-$(uname -r)
[ -e /run/booted-system/kernel ] && opt_kernel=/run/booted-system/kernel
fi
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# 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
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# config
if [ -e /proc/config.gz ] ; then
dumped_config="$(mktemp /tmp/config-XXXXXX)"
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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
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elif [ -e /boot/config-$(uname -r) ]; then
opt_config=/boot/config-$(uname -r)
fi
else
_info "Checking for vulnerabilities against specified kernel"
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fi
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if [ -n "$opt_kernel" ]; then
_verbose "Will use vmlinux image \033[35m$opt_kernel\033[0m"
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else
_verbose "Will use no vmlinux image (accuracy might be reduced)"
bad_accuracy=1
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fi
if [ -n "$dumped_config" ]; then
_verbose "Will use kconfig \033[35m/proc/config.gz\033[0m"
elif [ -n "$opt_config" ]; then
_verbose "Will use kconfig \033[35m$opt_config\033[0m"
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else
_verbose "Will use no kconfig (accuracy might be reduced)"
bad_accuracy=1
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fi
if [ -n "$opt_map" ]; then
_verbose "Will use System.map file \033[35m$opt_map\033[0m"
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else
_verbose "Will use no System.map file (accuracy might be reduced)"
bad_accuracy=1
fi
if [ "$bad_accuracy" = 1 ]; then
_info "We're missing some kernel info (see -v), accuracy might be reduced"
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fi
if [ -e "$opt_kernel" ]; then
if ! which readelf >/dev/null 2>&1; then
_debug "readelf not found"
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vmlinux_err="missing 'readelf' tool, please install it, usually it's in the 'binutils' package"
else
extract_vmlinux "$opt_kernel"
fi
else
_debug "no opt_kernel defined"
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vmlinux_err="couldn't find your kernel image in /boot, if you used netboot, this is normal"
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fi
if [ -z "$vmlinux" -o ! -r "$vmlinux" ]; then
[ -z "$vmlinux_err" ] && vmlinux_err="couldn't extract your kernel from $opt_kernel"
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fi
_info
# end of header stuff
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# now we define some util functions and the check_*() funcs, as
# the user can choose to execute only some of those
sys_interface_check()
{
[ "$opt_live" = 1 -a "$opt_no_sysfs" = 0 -a -r "$1" ] || return 1
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_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")
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_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
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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
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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
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# 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
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