mirror of
https://github.com/speed47/spectre-meltdown-checker
synced 2024-11-07 06:33:38 +01:00
302 lines
9.8 KiB
Bash
Executable File
302 lines
9.8 KiB
Bash
Executable File
#! /bin/sh
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# Spectre & Meltdown checker
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# Stephane Lesimple
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VERSION=0.10
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# print status function
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pstatus()
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{
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case "$1" in
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red) col="\033[101m\033[30m";;
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green) col="\033[102m\033[30m";;
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yellow) col="\033[103m\033[30m";;
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*) col="";;
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esac
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/bin/echo -ne "$col $2 \033[0m"
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[ -n "$3" ] && /bin/echo -n " ($3)"
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/bin/echo
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}
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# The 3 below functions are taken from the extract-linux script, available here:
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# https://github.com/torvalds/linux/blob/master/scripts/extract-vmlinux
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# The functions have been modified for better integration to this script
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# The original header of the file has been retained below
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# ----------------------------------------------------------------------
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# extract-vmlinux - Extract uncompressed vmlinux from a kernel image
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#
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# Inspired from extract-ikconfig
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# (c) 2009,2010 Dick Streefland <dick@streefland.net>
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#
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# (c) 2011 Corentin Chary <corentin.chary@gmail.com>
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#
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# Licensed under the GNU General Public License, version 2 (GPLv2).
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# ----------------------------------------------------------------------
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check_vmlinux()
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{
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file "$1" 2>/dev/null | grep -q ELF || return 1
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return 0
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}
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try_decompress()
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{
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# The obscure use of the "tr" filter is to work around older versions of
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# "grep" that report the byte offset of the line instead of the pattern.
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# Try to find the header ($1) and decompress from here
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for pos in `tr "$1\n$2" "\n$2=" < "$4" | grep -abo "^$2"`
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do
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pos=${pos%%:*}
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tail -c+$pos "$4" | $3 > $vmlinuxtmp 2> /dev/null
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check_vmlinux "$vmlinuxtmp" && echo "$vmlinuxtmp" && return 0
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done
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return 1
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}
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extract_vmlinux()
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{
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[ -n "$1" ] || return 1
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# Prepare temp files:
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vmlinuxtmp="$(mktemp /tmp/vmlinux-XXX)"
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# Initial attempt for uncompressed images or objects:
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if check_vmlinux "$1"; then
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cat "$1" > "$vmlinuxtmp"
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echo "$vmlinuxtmp"
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return 0
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fi
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# That didn't work, so retry after decompression.
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try_decompress '\037\213\010' xy gunzip "$1" && return 0
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try_decompress '\3757zXZ\000' abcde unxz "$1" && return 0
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try_decompress 'BZh' xy bunzip2 "$1" && return 0
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try_decompress '\135\0\0\0' xxx unlzma "$1" && return 0
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try_decompress '\211\114\132' xy 'lzop -d' "$1" && return 0
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return 1
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}
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# end of extract-vmlinux functions
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/bin/echo "Spectre and Meltdown mitigation detection tool v$VERSION"
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/bin/echo
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###########
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# SPECTRE 1
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/bin/echo -e "\033[1;34mCVE-2017-5753 [bounds check bypass] aka 'Spectre Variant 1'\033[0m"
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/bin/echo -n "* Kernel compiled with LFENCE opcode inserted at the proper places: "
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status=0
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img=''
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# try to find the image of the current running kernel
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[ -e /boot/vmlinuz-linux ] && img=/boot/vmlinuz-linux
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[ -e /boot/vmlinuz-$(uname -r) ] && img=/boot/vmlinuz-$(uname -r)
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[ -e /boot/kernel-$( uname -r) ] && img=/boot/kernel-$( uname -r)
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[ -e /boot/bzImage-$(uname -r) ] && img=/boot/bzImage-$(uname -r)
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[ -e /boot/kernel-genkernel-$(uname -m)-$(uname -r) ] && img=/boot/kernel-genkernel-$(uname -m)-$(uname -r)
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if [ -z "$img" ]; then
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pstatus yellow UNKNOWN "couldn't find your kernel image in /boot, if you used netboot, this is normal"
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else
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vmlinux=$(extract_vmlinux $img)
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if [ -z "$vmlinux" -o ! -r "$vmlinux" ]; then
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pstatus yellow UNKNOWN "couldn't extract your kernel from $img"
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elif ! which objdump >/dev/null 2>&1; then
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pstatus yellow UNKNOWN "missing 'objdump' tool, please install it, usually it's in the binutils package"
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else
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# here we disassemble the kernel and count the number of occurences of the LFENCE opcode
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# in non-patched kernels, this has been empirically determined as being around 40-50
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# in patched kernels, this is more around 70-80
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nb_lfence=$(objdump -D "$vmlinux" | grep -wc lfence)
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if [ "$nb_lfence" -lt 60 ]; then
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pstatus red NO "only $nb_lfence opcodes found, should be >= 60"
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status=1
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else
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pstatus green YES "$nb_lfence opcodes found, which is >= 60"
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status=2
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fi
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fi
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fi
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/bin/echo -ne "> \033[46m\033[30mSTATUS:\033[0m "
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[ "$status" = 0 ] && pstatus yellow UNKNOWN
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[ "$status" = 1 ] && pstatus red VULNERABLE
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[ "$status" = 2 ] && pstatus green 'NOT VULNERABLE'
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###########
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# VARIANT 2
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/bin/echo
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/bin/echo -e "\033[1;34mCVE-2017-5715 [branch target injection] aka 'Spectre Variant 2'\033[0m"
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/bin/echo "* Mitigation 1"
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/bin/echo -n "* Hardware (CPU microcode) support for mitigation: "
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if [ ! -e /dev/cpu/0/msr ]; then
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# try to load the module ourselves (and remember it so we can rmmod it afterwards)
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modprobe msr 2>/dev/null && insmod_msr=1
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fi
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if [ ! -e /dev/cpu/0/msr ]; then
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pstatus yellow UNKNOWN "couldn't read /dev/cpu/0/msr, is msr support enabled in your kernel?"
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else
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# the new MSR 'SPEC_CTRL' is at offset 0x48
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# here we use dd, it's the same as using 'rdmsr 0x48' but without needing the rdmsr tool
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# if we get a read error, the MSR is not there
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dd if=/dev/cpu/0/msr of=/dev/null bs=8 count=1 skip=9 2>/dev/null
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if [ $? -eq 0 ]; then
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pstatus green YES
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else
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pstatus red NO
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fi
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fi
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if [ "$insmod_msr" = 1 ]; then
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# if we used modprobe ourselves, rmmod the module
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rmmod msr 2>/dev/null
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fi
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/bin/echo -n "* Kernel support for IBRS: "
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if [ -e /sys/kernel/debug/sched_features ]; then
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# try to mount the debugfs hierarchy ourselves and remember it to umount afterwards
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mount -t debugfs debugfs /sys/kernel/debug 2>/dev/null && mounted_debugfs=1
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fi
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if [ -e /sys/kernel/debug/ibrs_enabled ]; then
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# if the file is there, we have IBRS compiled-in
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pstatus green YES
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ibrs_supported=1
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else
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pstatus red NO
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fi
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ibrs_enabled=$(cat /sys/kernel/debug/ibrs_enabled 2>/dev/null)
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/bin/echo -n "* IBRS enabled for Kernel space: "
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# 0 means disabled
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# 1 is enabled only for kernel space
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# 2 is enabled for kernel and user space
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case "$ibrs_enabled" in
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"") [ "$ibrs_supported" = 1 ] && pstatus yellow UNKNOWN || pstatus red NO;;
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0) pstatus red NO;;
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1 | 2) pstatus green YES;;
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*) pstatus yellow UNKNOWN;;
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esac
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/bin/echo -n "* IBRS enabled for User space: "
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case "$ibrs_enabled" in
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"") [ "$ibrs_supported" = 1 ] && pstatus yellow UNKNOWN || pstatus red NO;;
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0 | 1) pstatus red NO;;
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2) pstatus green YES;;
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*) pstatus yellow unknown;;
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esac
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if [ "$mounted_debugfs" = 1 ]; then
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# umount debugfs if we did mount it ourselves
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umount /sys/kernel/debug
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fi
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/bin/echo "* Mitigation 2"
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/bin/echo -n "* Kernel compiled with retpolines: "
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# We check the RETPOLINE kernel options
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# XXX this doesn't mean the kernel has been compiled with a retpoline-aware gcc
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# still looking for a way do detect that ...
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if [ -e /proc/config.gz ]; then
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# either the running kernel exports his own config
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if zgrep -q '^CONFIG_RETPOLINE=y' /proc/config.gz; then
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pstatus green YES
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retpoline=1
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else
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pstatus red NO
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fi
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elif [ -e /boot/config-$(uname -r) ]; then
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# or we can find a config file in /root with the kernel release name
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if grep -q '^CONFIG_RETPOLINE=y' /boot/config-$(uname -r); then
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pstatus green YES
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retpoline=1
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else
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pstatus red NO
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fi
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else
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pstatus yellow UNKNOWN "couldn't read your kernel configuration"
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fi
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/bin/echo -ne "> \033[46m\033[30mSTATUS:\033[0m "
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if grep -q AMD /proc/cpuinfo; then
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pstatus green "NOT VULNERABLE" "your CPU is not vulnerable as per the vendor"
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elif [ "$ibrs_enabled" = 1 -o "$ibrs_enabled" = 2 ]; then
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pstatus green "NOT VULNERABLE" "IBRS mitigates the vulnerability"
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elif [ "$retpoline" = 1 ]; then
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pstatus green "NOT VULNERABLE" "retpolines mitigate the vulnerability"
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else
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pstatus red VULNERABLE "IBRS hardware + kernel support OR kernel with retpolines are needed to mitigate the vulnerability"
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fi
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##########
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# MELTDOWN
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/bin/echo
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/bin/echo -e "\033[1;34mCVE-2017-5754 [rogue data cache load] aka 'Meltdown' aka 'Variant 3'\033[0m"
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/bin/echo -n "* Kernel supports Page Table Isolation (PTI): "
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kpti_support=0
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kpti_can_tell=0
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if [ -e /proc/config.gz ]; then
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# either the running kernel exports his own config
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kpti_can_tell=1
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if zgrep -q '^CONFIG_PAGE_TABLE_ISOLATION=y' /proc/config.gz; then
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kpti_support=1
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fi
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elif [ -e /boot/config-$(uname -r) ]; then
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# or we can find a config file in /root with the kernel release name
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kpti_can_tell=1
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if grep -q '^CONFIG_PAGE_TABLE_ISOLATION=y' /boot/config-$(uname -r); then
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kpti_support=1
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fi
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fi
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if [ -e /boot/System.map-$(uname -r) ]; then
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# it's not an elif: some backports don't have the PTI config but still include the patch
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# so we try to find an exported symbol that is part of the PTI patch in System.map
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kpti_can_tell=1
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if grep -qw kpti_force_enabled /boot/System.map-$(uname -r); then
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kpti_support=1
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fi
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fi
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if [ -n "$vmlinux" ]; then
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# same as above but in case we don't have System.map and only vmlinux, look for the
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# nopti option that is part of the patch (kernel command line option)
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kpti_can_tell=1
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if strings "$vmlinux" | grep -qw nopti; then
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kpti_support=1
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fi
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fi
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if [ "$kpti_support" = 1 ]; then
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pstatus green YES
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elif [ "$kpti_can_tell" = 1 ]; then
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pstatus red NO
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else
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pstatus yellow UNKNOWN "couldn't read your kernel configuration"
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fi
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/bin/echo -n "* PTI enabled and active: "
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if grep ^flags /proc/cpuinfo | grep -qw pti; then
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# vanilla PTI patch sets the 'pti' flag in cpuinfo
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pstatus green YES
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kpti_enabled=1
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elif dmesg | grep -Eq 'Kernel/User page tables isolation: enabled|Kernel page table isolation enabled'; then
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# if we can't find the flag, grep in dmesg
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pstatus green YES
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kpti_enabled=1
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else
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pstatus red NO
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fi
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/bin/echo -ne "> \033[46m\033[30mSTATUS:\033[0m "
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if grep -q AMD /proc/cpuinfo; then
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pstatus green "NOT VULNERABLE" "your CPU is not vulnerable as per the vendor"
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elif [ "$kpti_enabled" = 1 ]; then
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pstatus green "NOT VULNERABLE" "PTI mitigates the vulnerability"
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else
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pstatus red "VULNERABLE" "PTI is needed to mitigate the vulnerability"
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fi
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/bin/echo
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if [ "$(id -u)" -ne 0 ]; then
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/bin/echo "Note that you should launch this script with root privileges to get accurate information"
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/bin/echo "You can try the following command: sudo $0"
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fi
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[ -n "$vmlinux" -a -f "$vmlinux" ] && rm -f "$vmlinux"
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