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spectre-meltdown-checker/spectre-meltdown-checker.sh
2018-01-07 18:49:15 +01:00

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#! /bin/sh
# Spectre & Meltdown checker
# Stephane Lesimple
VERSION=0.07
pstatus()
{
case "$1" in
red) col="\033[101m\033[30m";;
green) col="\033[102m\033[30m";;
yellow) col="\033[103m\033[30m";;
*) col="";;
esac
/bin/echo -ne "$col $2 \033[0m"
[ -n "$3" ] && /bin/echo -n " ($3)"
/bin/echo
}
# ----------------------------------------------------------------------
# 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).
# ----------------------------------------------------------------------
check_vmlinux()
{
file "$1" 2>/dev/null | grep -q ELF || 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$2=" < "$img" | grep -abo "^$2"`
do
pos=${pos%%:*}
tail -c+$pos "$img" | $3 > $vmlinuxtmp 2> /dev/null
check_vmlinux $vmlinuxtmp && echo $vmlinuxtmp || rm -f $vmlinuxtmp
done
}
extract_vmlinux()
{
img="$1"
# Prepare temp files:
vmlinuxtmp=$(mktemp /tmp/vmlinux-XXX)
# Initial attempt for uncompressed images or objects:
check_vmlinux $img
# That didn't work, so retry after decompression.
try_decompress '\037\213\010' xy gunzip || \
try_decompress '\3757zXZ\000' abcde unxz || \
try_decompress 'BZh' xy bunzip2 || \
try_decompress '\135\0\0\0' xxx unlzma || \
try_decompress '\211\114\132' xy 'lzop -d'
}
/bin/echo "Spectre and Meltdown mitigation detection tool v$VERSION"
/bin/echo
# SPECTRE 1
/bin/echo -e "\033[1;34mCVE-2017-5753 [bounds check bypass] aka 'Spectre Variant 1'\033[0m"
/bin/echo -n "* Kernel compiled with LFENCE opcode inserted at the proper places: "
status=0
img=''
[ -e /boot/vmlinuz-$(uname -r) ] && img=/boot/vmlinuz-$(uname -r)
[ -e /boot/vmlinux-$(uname -r) ] && img=/boot/vmlinux-$(uname -r)
[ -e /boot/bzImage-$(uname -r) ] && img=/boot/bzImage-$(uname -r)
if [ -z "$img" ]; then
pstatus yellow UNKNOWN "couldn't find your kernel image in /boot"
else
vmlinux=$(extract_vmlinux $img)
if [ -z "$vmlinux" -o ! -r "$vmlinux" ]; then
pstatus yellow UNKNOWN "couldn't extract your kernel"
elif ! which objdump >/dev/null 2>&1; then
pstatus yellow UNKNOWN "missing 'objdump' tool, please install it, usually it's in the binutils package"
else
nb_lfence=$(objdump -D "$vmlinux" | grep -wc lfence)
if [ "$nb_lfence" -lt 60 ]; then
pstatus red NO "only $nb_lfence opcodes found, should be >= 60"
status=1
else
pstatus green YES "$nb_lfence opcodes found, which is >= 60"
status=2
fi
rm -f $vmlinux
fi
fi
/bin/echo -ne "> \033[46m\033[30mSTATUS:\033[0m "
[ "$status" = 0 ] && pstatus yellow UNKNOWN
[ "$status" = 1 ] && pstatus red VULNERABLE
[ "$status" = 2 ] && pstatus green 'NOT VULNERABLE'
# VARIANT 2
/bin/echo
/bin/echo -e "\033[1;34mCVE-2017-5715 [branch target injection] aka 'Spectre Variant 2'\033[0m"
/bin/echo "* Mitigation 1"
/bin/echo -n "* Hardware (CPU microcode) support for mitigation: "
if [ ! -e /dev/cpu/0/msr ]; then
modprobe msr 2>/dev/null && insmod_msr=1
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
# same that rdmsr 0x48 but without needing the rdmsr tool
dd if=/dev/cpu/0/msr of=/dev/null bs=8 count=1 skip=9 2>/dev/null
if [ $? -eq 0 ]; then
pstatus green YES
else
pstatus red NO
fi
fi
if [ "$insmod_msr" = 1 ]; then
rmmod msr 2>/dev/null
fi
/bin/echo -n "* Kernel support for IBRS: "
if [ -e /sys/kernel/debug/sched_features ]; then
mount -t debugfs debugfs /sys/kernel/debug 2>/dev/null && mounted_debugfs=1
fi
if [ -e /sys/kernel/debug/ibrs_enabled ]; then
pstatus green YES
ibrs_supported=1
else
pstatus red NO
fi
ibrs_enabled=$(cat /sys/kernel/debug/ibrs_enabled 2>/dev/null)
/bin/echo -n "* IBRS enabled for Kernel space: "
case "$ibrs_enabled" in
"") [ "$ibrs_supported" = 1 ] && pstatus yellow UNKNOWN || pstatus red NO;;
0) pstatus red NO;;
1 | 2) pstatus green YES;;
*) pstatus yellow UNKNOWN;;
esac
/bin/echo -n "* IBRS enabled for User space: "
case "$ibrs_enabled" in
"") [ "$ibrs_supported" = 1 ] && pstatus yellow UNKNOWN || pstatus red NO;;
0 | 1) pstatus red NO;;
2) pstatus green YES;;
*) pstatus yellow unknown;;
esac
if [ "$mounted_debugfs" = 1 ]; then
umount /sys/kernel/debug
fi
/bin/echo "* Mitigation 2"
/bin/echo -n "* Kernel compiled with retpolines: "
# XXX this doesn't mean the kernel has been compiled with a retpoline-aware gcc
if [ -e /proc/config.gz ]; then
if zgrep -q '^CONFIG_RETPOLINE=y' /proc/config.gz; then
pstatus green YES
retpoline=1
else
pstatus red NO
fi
elif [ -e /boot/config-$(uname -r) ]; then
if grep -q '^CONFIG_RETPOLINE=y' /boot/config-$(uname -r); then
pstatus green YES
retpoline=1
else
pstatus red NO
fi
else
pstatus yellow UNKNOWN "couldn't read your kernel configuration"
fi
/bin/echo -ne "> \033[46m\033[30mSTATUS:\033[0m "
if grep -q AMD /proc/cpuinfo; then
pstatus green "NOT VULNERABLE" "your CPU is not vulnerable as per the vendor"
elif [ "$ibrs_enabled" = 1 -o "$ibrs_enabled" = 2 ]; then
pstatus green "NOT VULNERABLE" "IBRS mitigates the vulnerability"
elif [ "$retpoline" = 1 ]; then
pstatus green "NOT VULNERABLE" "retpolines mitigate the vulnerability"
else
pstatus red VULNERABLE "IBRS hardware + kernel support OR kernel with retpolines are needed to mitigate the vulnerability"
fi
# MELTDOWN
/bin/echo
/bin/echo -e "\033[1;34mCVE-2017-5754 [rogue data cache load] aka 'Meltdown' aka 'Variant 3'\033[0m"
/bin/echo -n "* Kernel supports Page Table Isolation (PTI): "
if [ -e /proc/config.gz ]; then
if zgrep -q '^CONFIG_PAGE_TABLE_ISOLATION=y' /proc/config.gz; then
pstatus green YES
kpti_support=1
else
pstatus red NO
fi
elif [ -e /boot/config-$(uname -r) ]; then
if grep -q '^CONFIG_PAGE_TABLE_ISOLATION=y' /boot/config-$(uname -r); then
pstatus green YES
kpti_support=1
else
pstatus red NO
fi
elif [ -e /boot/System.map-$(uname -r) ]; then
if grep -qw kpti_force_enabled /boot/System.map-$(uname -r); then
pstatus green YES
kpti_support=1
else
pstatus red NO
fi
else
pstatus yellow UNKNOWN "couldn't read your kernel configuration"
fi
/bin/echo -n "* PTI enabled and active: "
if grep ^flags /proc/cpuinfo | grep -qw pti; then
pstatus green YES
kpti_enabled=1
elif dmesg | grep -q 'Kernel/User page tables isolation: enabled'; then
pstatus green YES
kpti_enabled=1
else
pstatus red NO
fi
/bin/echo -ne "> \033[46m\033[30mSTATUS:\033[0m "
if grep -q AMD /proc/cpuinfo; then
pstatus green "NOT VULNERABLE" "your CPU is not vulnerable as per the vendor"
elif [ "$kpti_enabled" = 1 ]; then
pstatus green "NOT VULNERABLE" "PTI mitigates the vulnerability"
else
pstatus red "VULNERABLE" "PTI is needed to mitigate the vulnerability"
fi
/bin/echo
if [ "$USER" != root ]; then
/bin/echo "Note that you should launch this script with root privileges to get accurate information"
/bin/echo "You can try the following command: sudo $0"
fi