#! /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 <] [--config ] [--map ] 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 </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 # # (c) 2011 Corentin Chary # # 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 support (CPU microcode)" _info " * Indirect Branch Restricted Speculation (IBRS)" _info_nol " * 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. bs has to be 8 for msr # skip=9 because 8*9=72=0x48 dd if=/dev/cpu/0/msr of=/dev/null bs=8 count=1 skip=9 2>/dev/null if [ $? -eq 0 ]; then pstatus green YES else pstatus red NO fi fi _info_nol " * CPU indicates IBRS capability: " if [ ! -e /dev/cpu/0/cpuid ]; then # try to load the module ourselves (and remember it so we can rmmod it afterwards) load_cpuid fi if [ ! -e /dev/cpu/0/cpuid ]; then pstatus yellow UNKNOWN "couldn't read /dev/cpu/0/cpuid, is cpuid support enabled in your kernel?" else # from kernel src: { X86_FEATURE_SPEC_CTRL, CPUID_EDX,26, 0x00000007, 0 }, if [ "$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=$?" _debug "cpuid: leaf7 eax-ebx-ecx-edx: "$(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 byte 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 "SPEC_CTRL feature bit" cpuid_spec_ctrl=1 else pstatus red NO fi fi # hardware support according to kernel if [ "$opt_verbose" -ge 2 ]; then # the spec_ctrl flag in cpuinfo is set if and only if the kernel sees # that the spec_ctrl cpuinfo bit set. we already check that ourselves above # but let's check it anyway (in verbose mode only) _verbose_nol " * Kernel has set the spec_ctrl flag in cpuinfo: " if [ "$opt_live" = 1 ]; then if grep ^flags /proc/cpuinfo | grep -qw spec_ctrl; then pstatus green YES else pstatus blue NO fi else pstatus blue N/A "not testable in offline mode" fi fi # IBPB _info " * Indirect Branch Prediction Barrier (IBPB)" _info_nol " * PRED_CMD MSR is available: " 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 'PRED_CTRL' is at offset 0x49, write-only # here we use dd, it's the same as using 'wrmsr 0x49 0' but without needing the wrmsr tool # if we get a write error, the MSR is not there $echo_cmd -ne "\0\0\0\0\0\0\0\0" | dd of=/dev/cpu/0/msr bs=8 count=1 seek=73 oflag=seek_bytes 2>/dev/null if [ $? -eq 0 ]; then pstatus green YES else pstatus red NO fi fi _info_nol " * CPU indicates IBPB capability: " if [ ! -e /dev/cpu/0/cpuid ]; then pstatus yellow UNKNOWN "couldn't read /dev/cpu/0/cpuidr, is cpuid support enabled in your kernel?" else # CPUID EAX=0x80000008, ECX=0x00 return EBX[12] indicates support for just IBPB. if [ "$opt_verbose" -ge 3 ]; then dd if=/dev/cpu/0/cpuid bs=16 skip=2147483656 iflag=skip_bytes count=1 >/dev/null 2>/dev/null _debug "cpuid: reading leaf80000008 of cpuid on cpu0, ret=$?" _debug "cpuid: leaf80000008 eax-ebx-ecx-edx: "$(dd if=/dev/cpu/0/cpuid bs=16 skip=2147483656 iflag=skip_bytes count=1 2>/dev/null | od -x -A n) _debug "cpuid: leaf80000008 ebx 3rd byte is: "$(dd if=/dev/cpu/0/cpuid bs=16 skip=2147483656 iflag=skip_bytes count=1 2>/dev/null | dd bs=1 skip=5 count=1 2>/dev/null | od -x -A n) fi # getting high byte of edx on leaf7 of cpuinfo in decimal ebx_b3=$(dd if=/dev/cpu/0/cpuid bs=16 skip=2147483656 iflag=skip_bytes count=1 2>/dev/null | dd bs=1 skip=5 count=1 2>/dev/null | od -t u -A n | awk '{print $1}') _debug "cpuid: leaf80000008 ebx 3rd byte: $ebx_b3 (decimal)" ebx_bit12=$(( ebx_b3 & 16 )) _debug "cpuid: ebx_bit12=$ebx_bit12" if [ "$ebx_bit12" -eq 16 ]; then pstatus green YES "IBPB_SUPPORT feature bit" cpuid_ibpb=1 elif [ "$cpuid_spec_ctrl" = 1 ]; then pstatus green YES "SPEC_CTRL feature bit" else pstatus red NO fi fi _info_nol " * Kernel is compiled with IBRS/IBPB support: " ibrs_can_tell=0 if [ "$opt_live" = 1 ]; then ibrs_can_tell=1 mount_debugfs for dir in \ /sys/kernel/debug \ /sys/kernel/debug/x86 \ /proc/sys/kernel; do if [ -e "$dir/ibrs_enabled" ]; then # if the file is there, we have IBRS compiled-in # /sys/kernel/debug/ibrs_enabled: vanilla # /sys/kernel/debug/x86/ibrs_enabled: RedHat (see https://access.redhat.com/articles/3311301) # /proc/sys/kernel/ibrs_enabled: OpenSUSE tumbleweed pstatus green YES ibrs_knob_dir=$dir ibrs_supported=1 ibrs_enabled=$(cat "$dir/ibrs_enabled" 2>/dev/null) _debug "ibrs: found $dir/ibrs_enabled=$ibrs_enabled" if [ -e "$dir/ibpb_enabled" ]; then ibpb_enabled=$(cat "$dir/ibpb_enabled" 2>/dev/null) _debug "ibpb: found $dir/ibpb_enabled=$ibpb_enabled" else _debug "ibpb: no ibpb_enabled file in $dir" fi break else _debug "ibrs: $dir/ibrs_enabled file doesn't exist" fi done # on some newer kernels, the spec_ctrl_ibrs flag in /proc/cpuinfo # is set when ibrs has been administratively enabled (usually from cmdline) # which in that case means ibrs is supported *and* enabled for kernel & user # as per the ibrs patch series v3 if [ "$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 # XXX and what about ibpb ? 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 [ "$ibrs_can_tell" = 1 ]; then pstatus red NO else # if we're in offline mode without System.map, we can't really know pstatus yellow UNKNOWN "in offline mode, we need System.map to be able to tell" fi fi _info " * Currently enabled features" _info_nol " * IBRS enabled for Kernel space: " if [ "$opt_live" = 1 ]; then if [ "$ibpb_enabled" = 2 ]; then # if ibpb=2, ibrs is forcefully=0 pstatus blue NO "IBPB used instead of IBRS in all kernel entrypoints" else # 0 means disabled # 1 is enabled only for kernel space # 2 is enabled for kernel and user space case "$ibrs_enabled" in "") [ "$ibrs_supported" = 1 ] && pstatus yellow UNKNOWN || pstatus red NO;; 0) pstatus red NO "echo 1 > $ibrs_knob_dir/ibrs_enabled";; 1 | 2) pstatus green YES;; *) pstatus yellow UNKNOWN;; esac fi else pstatus blue N/A "not testable in offline mode" fi _info_nol " * IBRS enabled for User space: " if [ "$opt_live" = 1 ]; then if [ "$ibpb_enabled" = 2 ]; then # if ibpb=2, ibrs is forcefully=0 pstatus blue NO "IBPB used instead of IBRS in all kernel entrypoints" else case "$ibrs_enabled" in "") [ "$ibrs_supported" = 1 ] && pstatus yellow UNKNOWN || pstatus red NO;; 0 | 1) pstatus red NO "echo 2 > $ibrs_knob_dir/ibrs_enabled";; 2) pstatus green YES;; *) pstatus yellow UNKNOWN;; esac fi else pstatus blue N/A "not testable in offline mode" fi _info_nol " * IBPB enabled: " if [ "$opt_live" = 1 ]; then case "$ibpb_enabled" in "") [ "$ibrs_supported" = 1 ] && pstatus yellow UNKNOWN || pstatus red NO;; 0) pstatus red NO "echo 1 > $ibrs_knob_dir/ibpb_enabled";; 1) pstatus green YES;; 2) pstatus green YES "IBPB used instead of IBRS in all kernel entrypoints";; *) pstatus yellow UNKNOWN;; esac else pstatus blue N/A "not testable in offline mode" fi unload_msr unload_cpuid _info "* Mitigation 2" _info_nol "* Kernel compiled with retpoline option: " # We check the RETPOLINE kernel options if [ -r "$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 "$ibrs_enabled" = 2 ] && [ "$ibpb_enabled" = 1 ]; then pvulnstatus CVE-2017-5715 OK "IBRS/IBPB are mitigating the vulnerability" elif [ "$ibpb_enabled" = 2 ]; then pvulnstatus CVE-2017-5715 OK "Full IBPB is mitigating the vulnerability" else pvulnstatus CVE-2017-5715 VULN "IBRS hardware + kernel support OR kernel with retpoline are needed to mitigate the vulnerability" fi else if [ "$ibrs_supported" = 1 ]; then pvulnstatus CVE-2017-5715 OK "offline mode: IBRS/IBPB 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