mirror of
https://github.com/speed47/spectre-meltdown-checker
synced 2024-11-19 04:22:22 +01:00
add some comments, enhance pti detection
This commit is contained in:
Stéphane Lesimple
parent
5c14384e15
commit
fa0850466e
@ -3,6 +3,7 @@
|
||||
# Stephane Lesimple
|
||||
VERSION=0.09
|
||||
|
||||
# print status function
|
||||
pstatus()
|
||||
{
|
||||
case "$1" in
|
||||
@ -16,6 +17,11 @@ pstatus()
|
||||
/bin/echo
|
||||
}
|
||||
|
||||
# The 3 below functions are taken from the extract-linux script, available here:
|
||||
# https://github.com/torvalds/linux/blob/master/scripts/extract-vmlinux
|
||||
# The functions have been modified for better integration to this script
|
||||
# The original header of the file has been retained below
|
||||
|
||||
# ----------------------------------------------------------------------
|
||||
# extract-vmlinux - Extract uncompressed vmlinux from a kernel image
|
||||
#
|
||||
@ -69,29 +75,35 @@ extract_vmlinux()
|
||||
try_decompress '\211\114\132' xy 'lzop -d'
|
||||
}
|
||||
|
||||
# end of extract-vmlinux functions
|
||||
|
||||
/bin/echo "Spectre and Meltdown mitigation detection tool v$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=''
|
||||
# try to find the image of the current running kernel
|
||||
[ -e /boot/vmlinuz-$(uname -r) ] && img=/boot/vmlinuz-$(uname -r)
|
||||
[ -e /boot/vmlinux-$(uname -r) ] && img=/boot/vmlinux-$(uname -r)
|
||||
[ -e /boot/kernel-$( uname -r) ] && img=/boot/kernel-$( uname -r)
|
||||
[ -e /boot/bzImage-$(uname -r) ] && img=/boot/bzImage-$(uname -r)
|
||||
if [ -z "$img" ]; then
|
||||
pstatus yellow UNKNOWN "couldn't find your kernel image in /boot"
|
||||
pstatus yellow UNKNOWN "couldn't find your kernel image in /boot, if you used netboot, this is normal"
|
||||
else
|
||||
vmlinux=$(extract_vmlinux $img)
|
||||
if [ -z "$vmlinux" -o ! -r "$vmlinux" ]; then
|
||||
pstatus yellow UNKNOWN "couldn't extract your kernel"
|
||||
pstatus yellow UNKNOWN "couldn't extract your kernel from $img"
|
||||
elif ! which objdump >/dev/null 2>&1; then
|
||||
pstatus yellow UNKNOWN "missing 'objdump' tool, please install it, usually it's in the binutils package"
|
||||
else
|
||||
# here we disassemble the kernel and count the number of occurences of the LFENCE opcode
|
||||
# in non-patched kernels, this has been empirically determined as being around 40-50
|
||||
# in patched kernels, this is more around 70-80
|
||||
nb_lfence=$(objdump -D "$vmlinux" | grep -wc lfence)
|
||||
if [ "$nb_lfence" -lt 60 ]; then
|
||||
pstatus red NO "only $nb_lfence opcodes found, should be >= 60"
|
||||
@ -108,19 +120,22 @@ fi
|
||||
[ "$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
|
||||
# try to load the module ourselves (and remember it so we can rmmod it afterwards)
|
||||
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
|
||||
# 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 [ $? -eq 0 ]; then
|
||||
pstatus green YES
|
||||
@ -130,14 +145,17 @@ else
|
||||
fi
|
||||
|
||||
if [ "$insmod_msr" = 1 ]; then
|
||||
# if we used modprobe ourselves, rmmod the module
|
||||
rmmod msr 2>/dev/null
|
||||
fi
|
||||
|
||||
/bin/echo -n "* Kernel support for IBRS: "
|
||||
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
|
||||
if [ -e /sys/kernel/debug/ibrs_enabled ]; then
|
||||
# if the file is there, we have IBRS compiled-in
|
||||
pstatus green YES
|
||||
ibrs_supported=1
|
||||
else
|
||||
@ -146,6 +164,9 @@ fi
|
||||
|
||||
ibrs_enabled=$(cat /sys/kernel/debug/ibrs_enabled 2>/dev/null)
|
||||
/bin/echo -n "* IBRS enabled for Kernel space: "
|
||||
# 0 means disabled
|
||||
# 1 is enabled only for kernel space
|
||||
# 2 is enabled for kernel and user space
|
||||
case "$ibrs_enabled" in
|
||||
"") [ "$ibrs_supported" = 1 ] && pstatus yellow UNKNOWN || pstatus red NO;;
|
||||
0) pstatus red NO;;
|
||||
@ -162,13 +183,17 @@ case "$ibrs_enabled" in
|
||||
esac
|
||||
|
||||
if [ "$mounted_debugfs" = 1 ]; then
|
||||
# umount debugfs if we did mount it ourselves
|
||||
umount /sys/kernel/debug
|
||||
fi
|
||||
|
||||
/bin/echo "* Mitigation 2"
|
||||
/bin/echo -n "* Kernel compiled with retpolines: "
|
||||
# We check the RETPOLINE kernel options
|
||||
# XXX this doesn't mean the kernel has been compiled with a retpoline-aware gcc
|
||||
# still looking for a way do detect that ...
|
||||
if [ -e /proc/config.gz ]; then
|
||||
# either the running kernel exports his own config
|
||||
if zgrep -q '^CONFIG_RETPOLINE=y' /proc/config.gz; then
|
||||
pstatus green YES
|
||||
retpoline=1
|
||||
@ -176,6 +201,7 @@ if [ -e /proc/config.gz ]; then
|
||||
pstatus red NO
|
||||
fi
|
||||
elif [ -e /boot/config-$(uname -r) ]; then
|
||||
# or we can find a config file in /root with the kernel release name
|
||||
if grep -q '^CONFIG_RETPOLINE=y' /boot/config-$(uname -r); then
|
||||
pstatus green YES
|
||||
retpoline=1
|
||||
@ -197,48 +223,58 @@ else
|
||||
pstatus red VULNERABLE "IBRS hardware + kernel support OR kernel with retpolines are needed to mitigate the vulnerability"
|
||||
fi
|
||||
|
||||
##########
|
||||
# MELTDOWN
|
||||
/bin/echo
|
||||
/bin/echo -e "\033[1;34mCVE-2017-5754 [rogue data cache load] aka 'Meltdown' aka 'Variant 3'\033[0m"
|
||||
/bin/echo -n "* Kernel supports Page Table Isolation (PTI): "
|
||||
kpti_support=0
|
||||
kpti_can_tell=0
|
||||
if [ -e /proc/config.gz ]; then
|
||||
# either the running kernel exports his own config
|
||||
kpti_can_tell=1
|
||||
if zgrep -q '^CONFIG_PAGE_TABLE_ISOLATION=y' /proc/config.gz; then
|
||||
pstatus green YES
|
||||
kpti_support=1
|
||||
else
|
||||
pstatus red NO
|
||||
fi
|
||||
elif [ -e /boot/config-$(uname -r) ]; then
|
||||
# or we can find a config file in /root with the kernel release name
|
||||
kpti_can_tell=1
|
||||
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
|
||||
fi
|
||||
if [ -e /boot/System.map-$(uname -r) ]; then
|
||||
# it's not an elif: some backports don't have the PTI config but still include the patch
|
||||
# so we try to find an exported symbol that is part of the PTI patch in System.map
|
||||
kpti_can_tell=1
|
||||
if grep -qw kpti_force_enabled /boot/System.map-$(uname -r); then
|
||||
pstatus green YES
|
||||
kpti_support=1
|
||||
else
|
||||
pstatus red NO
|
||||
fi
|
||||
elif [ -n "$vmlinux" ]; then
|
||||
# some backports don't have the option but still have the patch, try to find out
|
||||
fi
|
||||
if [ -n "$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 strings "$vmlinux" | grep -qw nopti; then
|
||||
pstatus green YES
|
||||
kpti_support=1
|
||||
else
|
||||
pstatus red NO
|
||||
fi
|
||||
fi
|
||||
|
||||
if [ "$kpti_support" = 1 ]; then
|
||||
pstatus green YES
|
||||
elif [ "$kpti_can_tell" = 1 ]; then
|
||||
pstatus red NO
|
||||
else
|
||||
pstatus yellow UNKNOWN "couldn't read your kernel configuration"
|
||||
fi
|
||||
|
||||
/bin/echo -n "* PTI enabled and active: "
|
||||
if grep ^flags /proc/cpuinfo | grep -qw pti; then
|
||||
# vanilla PTI patch sets the 'pti' flag in cpuinfo
|
||||
pstatus green YES
|
||||
kpti_enabled=1
|
||||
elif dmesg | grep -Eq 'Kernel/User page tables isolation: enabled|Kernel page table isolation enabled'; then
|
||||
# if we can't find the flag, grep in dmesg
|
||||
pstatus green YES
|
||||
kpti_enabled=1
|
||||
else
|
||||
@ -254,7 +290,6 @@ else
|
||||
pstatus red "VULNERABLE" "PTI is needed to mitigate the vulnerability"
|
||||
fi
|
||||
|
||||
|
||||
/bin/echo
|
||||
if [ "$(id -u)" -ne 0 ]; then
|
||||
/bin/echo "Note that you should launch this script with root privileges to get accurate information"
|
||||
@ -262,4 +297,3 @@ if [ "$(id -u)" -ne 0 ]; then
|
||||
fi
|
||||
|
||||
[ -n "$vmlinux" -a -f "$vmlinux" ] && rm -f "$vmlinux"
|
||||
|
||||
|
||||
Loading…
Reference in New Issue
Block a user