adding support for new /sys interface (#55)

* adding support for new /sys interface
* fix(objdump): prefer -d instead of -D, some kernels crash objdump otherwise
This commit is contained in:
Stéphane Lesimple 2018-01-11 12:23:16 +01:00 committed by GitHub
parent 56b67f8082
commit 62f8ed6f61
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@ -8,7 +8,7 @@
# #
# Stephane Lesimple # Stephane Lesimple
# #
VERSION=0.25 VERSION=0.26
# Script configuration # Script configuration
show_usage() show_usage()
@ -33,7 +33,8 @@ show_usage()
Options: Options:
--no-color Don't use color codes --no-color Don't use color codes
-v, --verbose Increase verbosity level --verbose, -v Increase verbosity level
--no-sysfs Don't use the /sys interface even if present
--batch text Produce machine readable output, this is the default if --batch is specified alone --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 json Produce JSON output formatted for Puppet, Ansible, Chef...
--batch nrpe Produce machine readable output formatted for NRPE --batch nrpe Produce machine readable output formatted for NRPE
@ -86,6 +87,7 @@ opt_variant1=0
opt_variant2=0 opt_variant2=0
opt_variant3=0 opt_variant3=0
opt_allvariants=1 opt_allvariants=1
opt_no_sysfs=0
nrpe_critical=0 nrpe_critical=0
nrpe_unknown=0 nrpe_unknown=0
@ -95,13 +97,13 @@ __echo()
{ {
opt="$1" opt="$1"
shift shift
msg="$@" _msg="$@"
if [ "$opt_no_color" = 1 ] ; then if [ "$opt_no_color" = 1 ] ; then
# strip ANSI color codes # strip ANSI color codes
msg=$(/bin/echo -e "$msg" | sed -r "s/\x1B\[([0-9]{1,2}(;[0-9]{1,2})?)?[m|K]//g") _msg=$(/bin/echo -e "$_msg" | sed -r "s/\x1B\[([0-9]{1,2}(;[0-9]{1,2})?)?[m|K]//g")
fi fi
# explicitely call /bin/echo to avoid shell builtins that might not take options # explicitely call /bin/echo to avoid shell builtins that might not take options
/bin/echo $opt -e "$msg" /bin/echo $opt -e "$_msg"
} }
_echo() _echo()
@ -250,6 +252,9 @@ while [ -n "$1" ]; do
elif [ "$1" = "--no-color" ]; then elif [ "$1" = "--no-color" ]; then
opt_no_color=1 opt_no_color=1
shift shift
elif [ "$1" = "--no-sysfs" ]; then
opt_no_sysfs=1
shift
elif [ "$1" = "--batch" ]; then elif [ "$1" = "--batch" ]; then
opt_batch=1 opt_batch=1
opt_verbose=0 opt_verbose=0
@ -548,46 +553,83 @@ umount_debugfs()
fi fi
} }
sys_interface_check()
{
[ "$opt_live" = 1 -a "$opt_no_sysfs" = 0 -a -r "$1" ] || return 1
_info_nol "* Checking wheter 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 "$1")
return 0
}
################### ###################
# SPECTRE VARIANT 1 # SPECTRE VARIANT 1
check_variant1() check_variant1()
{ {
_info "\033[1;34mCVE-2017-5753 [bounds check bypass] aka 'Spectre Variant 1'\033[0m" _info "\033[1;34mCVE-2017-5753 [bounds check bypass] aka 'Spectre Variant 1'\033[0m"
_info_nol "* Checking count of LFENCE opcodes in kernel: "
status=0 status=UNK
if [ -n "$vmlinux_err" ]; then sys_interface_available=0
pstatus yellow UNKNOWN "$vmlinux_err" msg=''
if sys_interface_check "/sys/devices/system/cpu/vulnerabilities/spectre_v1"; then
# this kernel has the /sys interface, trust it over everything
sys_interface_available=1
else else
if ! which objdump >/dev/null 2>&1; then # no /sys interface (or offline mode), fallback to our own ways
pstatus yellow UNKNOWN "missing 'objdump' tool, please install it, usually it's in the binutils package" _info_nol "* Checking count of LFENCE opcodes in kernel: "
if [ -n "$vmlinux_err" ]; then
msg="couldn't check ($vmlinux_err)"
status=UNK
pstatus yellow UNKNOWN
else else
# here we disassemble the kernel and count the number of occurences of the LFENCE opcode if ! which objdump >/dev/null 2>&1; then
# in non-patched kernels, this has been empirically determined as being around 40-50 msg="missing 'objdump' tool, please install it, usually it's in the binutils package"
# in patched kernels, this is more around 70-80, sometimes way higher (100+) status=UNK
# v0.13: 68 found in a 3.10.23-xxxx-std-ipv6-64 (with lots of modules compiled-in directly), which doesn't have the LFENCE patches, pstatus yellow UNKNOWN
# so let's push the threshold to 70.
# TODO LKML patch is starting to dump LFENCE in favor of the PAUSE opcode, we might need to check that (patch not stabilized yet)
nb_lfence=$(objdump -D "$vmlinux" | grep -wc lfence)
if [ "$nb_lfence" -lt 70 ]; then
pstatus red NO "only $nb_lfence opcodes found, should be >= 70"
status=1
else else
pstatus green YES "$nb_lfence opcodes found, which is >= 70" # here we disassemble the kernel and count the number of occurences of the LFENCE opcode
status=2 # 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 $nb_lfence opcodes found, should be >= 70, heuristic to be improved when official patches become available"
status=VULN
pstatus yellow UNKNOWN
else
msg="$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 fi
fi fi
if ! is_cpu_vulnerable 1; then # if we have the /sys interface, don't even check is_cpu_vulnerable ourselves, the kernel already does it
pvulnstatus CVE-2017-5753 OK "your CPU vendor reported your CPU model as not vulnerable" if [ "$sys_interface_available" = 0 ] && ! is_cpu_vulnerable 1; then
else # override status & msg in case CPU is not vulnerable after all
case "$status" in msg="your CPU vendor reported your CPU model as not vulnerable"
0) pvulnstatus CVE-2017-5753 UNK "impossible to check ${vmlinux}";; status=OK
1) pvulnstatus CVE-2017-5753 VULN 'heuristic to be improved when official patches become available';;
2) pvulnstatus CVE-2017-5753 OK 'heuristic to be improved when official patches become available';;
esac
fi fi
# report status
pvulnstatus CVE-2017-5753 "$status" "$msg"
} }
################### ###################
@ -595,153 +637,169 @@ check_variant1()
check_variant2() check_variant2()
{ {
_info "\033[1;34mCVE-2017-5715 [branch target injection] aka 'Spectre Variant 2'\033[0m" _info "\033[1;34mCVE-2017-5715 [branch target injection] aka 'Spectre Variant 2'\033[0m"
_info "* Mitigation 1"
_info_nol "* Hardware (CPU microcode) support for mitigation: " status=UNK
if [ ! -e /dev/cpu/0/msr ]; then sys_interface_available=0
# try to load the module ourselves (and remember it so we can rmmod it afterwards) msg=''
modprobe msr 2>/dev/null && insmod_msr=1 if sys_interface_check "/sys/devices/system/cpu/vulnerabilities/spectre_v2"; then
fi # this kernel has the /sys interface, trust it over everything
if [ ! -e /dev/cpu/0/msr ]; then sys_interface_available=1
pstatus yellow UNKNOWN "couldn't read /dev/cpu/0/msr, is msr support enabled in your kernel?"
else else
# the new MSR 'SPEC_CTRL' is at offset 0x48 _info "* Mitigation 1"
# here we use dd, it's the same as using 'rdmsr 0x48' but without needing the rdmsr tool _info_nol "* Hardware (CPU microcode) support for mitigation: "
# if we get a read error, the MSR is not there if [ ! -e /dev/cpu/0/msr ]; then
dd if=/dev/cpu/0/msr of=/dev/null bs=8 count=1 skip=9 2>/dev/null # try to load the module ourselves (and remember it so we can rmmod it afterwards)
if [ $? -eq 0 ]; then modprobe msr 2>/dev/null && insmod_msr=1
pstatus green YES
else
pstatus red NO
fi fi
fi if [ ! -e /dev/cpu/0/msr ]; then
pstatus yellow UNKNOWN "couldn't read /dev/cpu/0/msr, is msr support enabled in your kernel?"
if [ "$insmod_msr" = 1 ]; then else
# if we used modprobe ourselves, rmmod the module # the new MSR 'SPEC_CTRL' is at offset 0x48
rmmod msr 2>/dev/null # here we use dd, it's the same as using 'rdmsr 0x48' but without needing the rdmsr tool
fi # 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
_info_nol "* Kernel support for IBRS: " if [ $? -eq 0 ]; then
if [ "$opt_live" = 1 ]; then
mount_debugfs
for ibrs_file in \
/sys/kernel/debug/ibrs_enabled \
/sys/kernel/debug/x86/ibrs_enabled \
/proc/sys/kernel/ibrs_enabled; do
if [ -e "$ibrs_file" ]; then
# if the file is there, we have IBRS compiled-in
# /sys/kernel/debug/ibrs_enabled: vanilla
# /sys/kernel/debug/x86/ibrs_enabled: RedHat (see https://access.redhat.com/articles/3311301)
# /proc/sys/kernel/ibrs_enabled: OpenSUSE tumbleweed
pstatus green YES pstatus green YES
ibrs_supported=1
ibrs_enabled=$(cat "$ibrs_file" 2>/dev/null)
break
fi
done
fi
if [ "$ibrs_supported" != 1 -a -n "$opt_map" ]; then
if grep -q spec_ctrl "$opt_map"; then
pstatus green YES
ibrs_supported=1
fi
fi
if [ "$ibrs_supported" != 1 ]; then
pstatus red NO
fi
_info_nol "* IBRS enabled for Kernel space: "
if [ "$opt_live" = 1 ]; then
# 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;;
1 | 2) pstatus green YES;;
*) pstatus yellow UNKNOWN;;
esac
else
pstatus blue N/A "not testable in offline mode"
fi
_info_nol "* IBRS enabled for User space: "
if [ "$opt_live" = 1 ]; then
case "$ibrs_enabled" in
"") [ "$ibrs_supported" = 1 ] && pstatus yellow UNKNOWN || pstatus red NO;;
0 | 1) pstatus red NO;;
2) pstatus green YES;;
*) pstatus yellow UNKNOWN;;
esac
else
pstatus blue N/A "not testable in offline mode"
fi
_info "* Mitigation 2"
_info_nol "* Kernel compiled with retpoline option: "
# We check the RETPOLINE kernel options
if [ -r "$opt_config" ]; then
if grep -q '^CONFIG_RETPOLINE=y' "$opt_config"; then
pstatus green YES
retpoline=1
else
pstatus red NO
fi
else
pstatus yellow UNKNOWN "couldn't read your kernel configuration"
fi
_info_nol "* Kernel compiled with a retpoline-aware compiler: "
# Now check if the compiler used to compile the kernel knows how to insert retpolines in generated asm
# For gcc, this is -mindirect-branch=thunk-extern (detected by the kernel makefiles)
# See gcc commit https://github.com/hjl-tools/gcc/commit/23b517d4a67c02d3ef80b6109218f2aadad7bd79
# In latest retpoline LKML patches, the noretpoline_setup symbol exists only if CONFIG_RETPOLINE is set
# *AND* if the compiler is retpoline-compliant, so look for that symbol
if [ -n "$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 "$vmlinux" 2>/dev/null | grep -qw 'noretpoline_setup'; then
retpoline_compiler=1
pstatus green YES "noretpoline_setup found in vmlinux symbols"
else else
pstatus red NO pstatus red NO
fi fi
elif grep -q noretpoline_setup "$vmlinux"; then fi
# 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 if [ "$insmod_msr" = 1 ]; then
retpoline_compiler=1 # if we used modprobe ourselves, rmmod the module
pstatus green YES "noretpoline_setup found in vmlinux" rmmod msr 2>/dev/null
else fi
_info_nol "* Kernel support for IBRS: "
if [ "$opt_live" = 1 ]; then
mount_debugfs
for ibrs_file in \
/sys/kernel/debug/ibrs_enabled \
/sys/kernel/debug/x86/ibrs_enabled \
/proc/sys/kernel/ibrs_enabled; do
if [ -e "$ibrs_file" ]; then
# if the file is there, we have IBRS compiled-in
# /sys/kernel/debug/ibrs_enabled: vanilla
# /sys/kernel/debug/x86/ibrs_enabled: RedHat (see https://access.redhat.com/articles/3311301)
# /proc/sys/kernel/ibrs_enabled: OpenSUSE tumbleweed
pstatus green YES
ibrs_supported=1
ibrs_enabled=$(cat "$ibrs_file" 2>/dev/null)
break
fi
done
fi
if [ "$ibrs_supported" != 1 -a -n "$opt_map" ]; then
if grep -q spec_ctrl "$opt_map"; then
pstatus green YES
ibrs_supported=1
fi
fi
if [ "$ibrs_supported" != 1 ]; then
pstatus red NO pstatus red NO
fi fi
else
pstatus yellow UNKNOWN "couldn't find your kernel image or System.map" _info_nol "* IBRS enabled for Kernel space: "
if [ "$opt_live" = 1 ]; then
# 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;;
1 | 2) pstatus green YES;;
*) pstatus yellow UNKNOWN;;
esac
else
pstatus blue N/A "not testable in offline mode"
fi
_info_nol "* IBRS enabled for User space: "
if [ "$opt_live" = 1 ]; then
case "$ibrs_enabled" in
"") [ "$ibrs_supported" = 1 ] && pstatus yellow UNKNOWN || pstatus red NO;;
0 | 1) pstatus red NO;;
2) pstatus green YES;;
*) pstatus yellow UNKNOWN;;
esac
else
pstatus blue N/A "not testable in offline mode"
fi
_info "* Mitigation 2"
_info_nol "* Kernel compiled with retpoline option: "
# We check the RETPOLINE kernel options
if [ -r "$opt_config" ]; then
if grep -q '^CONFIG_RETPOLINE=y' "$opt_config"; then
pstatus green YES
retpoline=1
else
pstatus red NO
fi
else
pstatus yellow UNKNOWN "couldn't read your kernel configuration"
fi
_info_nol "* Kernel compiled with a retpoline-aware compiler: "
# Now check if the compiler used to compile the kernel knows how to insert retpolines in generated asm
# For gcc, this is -mindirect-branch=thunk-extern (detected by the kernel makefiles)
# See gcc commit https://github.com/hjl-tools/gcc/commit/23b517d4a67c02d3ef80b6109218f2aadad7bd79
# In latest retpoline LKML patches, the noretpoline_setup symbol exists only if CONFIG_RETPOLINE is set
# *AND* if the compiler is retpoline-compliant, so look for that symbol
if [ -n "$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 fi
if ! is_cpu_vulnerable 2; then # if we have the /sys interface, don't even check is_cpu_vulnerable ourselves, the kernel already does it
if [ "$sys_interface_available" = 0 ] && ! is_cpu_vulnerable 2; then
# override status & msg in case CPU is not vulnerable after all
pvulnstatus CVE-2017-5715 OK "your CPU vendor reported your CPU model as not vulnerable" pvulnstatus CVE-2017-5715 OK "your CPU vendor reported your CPU model as not vulnerable"
elif [ "$retpoline" = 1 -a "$retpoline_compiler" = 1 ]; then elif [ -z "$msg" ]; then
pvulnstatus CVE-2017-5715 OK "retpoline mitigate the vulnerability" # if msg is empty, sysfs check didn't fill it, rely on our own test
elif [ "$opt_live" = 1 ]; then if [ "$retpoline" = 1 -a "$retpoline_compiler" = 1 ]; then
if [ "$ibrs_enabled" = 1 -o "$ibrs_enabled" = 2 ]; then pvulnstatus CVE-2017-5715 OK "retpoline mitigate the vulnerability"
pvulnstatus CVE-2017-5715 OK "IBRS mitigates the vulnerability" elif [ "$opt_live" = 1 ]; then
if [ "$ibrs_enabled" = 1 -o "$ibrs_enabled" = 2 ]; then
pvulnstatus CVE-2017-5715 OK "IBRS mitigates the vulnerability"
else
pvulnstatus CVE-2017-5715 VULN "IBRS hardware + kernel support OR kernel with retpoline are needed to mitigate the vulnerability"
fi
else else
pvulnstatus CVE-2017-5715 VULN "IBRS hardware + kernel support OR kernel with retpoline are needed to mitigate the vulnerability" if [ "$ibrs_supported" = 1 ]; then
pvulnstatus CVE-2017-5715 OK "offline mode: IBRS will mitigate the vulnerability if enabled at runtime"
else
pvulnstatus CVE-2017-5715 VULN "IBRS hardware + kernel support OR kernel with retpoline are needed to mitigate the vulnerability"
fi
fi fi
else else
if [ "$ibrs_supported" = 1 ]; then pvulnstatus CVE-2017-5715 "$status" "$msg"
pvulnstatus CVE-2017-5715 OK "offline mode: IBRS will mitigate the vulnerability if enabled at runtime"
else
pvulnstatus CVE-2017-5715 VULN "IBRS hardware + kernel support OR kernel with retpoline are needed to mitigate the vulnerability"
fi
fi fi
} }
@ -750,88 +808,105 @@ check_variant2()
check_variant3() check_variant3()
{ {
_info "\033[1;34mCVE-2017-5754 [rogue data cache load] aka 'Meltdown' aka 'Variant 3'\033[0m" _info "\033[1;34mCVE-2017-5754 [rogue data cache load] aka 'Meltdown' aka 'Variant 3'\033[0m"
_info_nol "* Kernel supports Page Table Isolation (PTI): "
kpti_support=0 status=UNK
kpti_can_tell=0 sys_interface_available=0
if [ -n "$opt_config" ]; then msg=''
kpti_can_tell=1 if sys_interface_check "/sys/devices/system/cpu/vulnerabilities/meltdown"; then
if grep -Eq '^(CONFIG_PAGE_TABLE_ISOLATION|CONFIG_KAISER)=y' "$opt_config"; then # this kernel has the /sys interface, trust it over everything
kpti_support=1 sys_interface_available=1
fi else
fi _info_nol "* Kernel supports Page Table Isolation (PTI): "
if [ "$kpti_support" = 0 -a -n "$opt_map" ]; then kpti_support=0
# it's not an elif: some backports don't have the PTI config but still include the patch kpti_can_tell=0
# so we try to find an exported symbol that is part of the PTI patch in System.map if [ -n "$opt_config" ]; then
kpti_can_tell=1 kpti_can_tell=1
if grep -qw kpti_force_enabled "$opt_map"; then if grep -Eq '^(CONFIG_PAGE_TABLE_ISOLATION|CONFIG_KAISER)=y' "$opt_config"; then
kpti_support=1
fi
fi
if [ "$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
kpti_support=1 kpti_support=1
fi fi
fi 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
if [ "$kpti_support" = 1 ]; then # so we try to find an exported symbol that is part of the PTI patch in System.map
pstatus green YES kpti_can_tell=1
elif [ "$kpti_can_tell" = 1 ]; then if grep -qw kpti_force_enabled "$opt_map"; then
pstatus red NO kpti_support=1
else fi
pstatus yellow UNKNOWN "couldn't read your kernel configuration nor System.map file"
fi
mount_debugfs
_info_nol "* PTI enabled and active: "
if [ "$opt_live" = 1 ]; then
if grep ^flags /proc/cpuinfo | grep -qw pti; then
# vanilla PTI patch sets the 'pti' flag in cpuinfo
kpti_enabled=1
elif grep ^flags /proc/cpuinfo | grep -qw kaiser; then
# kernel line 4.9 sets the 'kaiser' flag in 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=$(cat /sys/kernel/debug/x86/pti_enabled 2>/dev/null)
elif dmesg | grep -Eq 'Kernel/User page tables isolation: enabled|Kernel page table isolation enabled'; then
# if we can't find the flag, grep dmesg output
kpti_enabled=1
elif [ -r /var/log/dmesg ] && grep -Eq 'Kernel/User page tables isolation: enabled|Kernel page table isolation enabled' /var/log/dmesg; then
# if we can't find the flag in dmesg output, grep in /var/log/dmesg when readable
kpti_enabled=1
else
kpti_enabled=0
fi fi
if [ "$kpti_enabled" = 1 ]; then if [ "$kpti_support" = 0 -a -n "$vmlinux" ]; then
pstatus green YES # same as above but in case we don't have System.map and only vmlinux, look for the
else # nopti option that is part of the patch (kernel command line option)
pstatus red NO 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 "$vmlinux" | grep -qw nopti; then
kpti_support=1
fi
fi
fi fi
else
pstatus blue N/A "can't verify if PTI is enabled in offline mode"
fi
if ! is_cpu_vulnerable 3; then
pvulnstatus CVE-2017-5754 OK "your CPU vendor reported your CPU model as not vulnerable"
elif [ "$opt_live" = 1 ]; then
if [ "$kpti_enabled" = 1 ]; then
pvulnstatus CVE-2017-5754 OK "PTI mitigates the vulnerability"
else
pvulnstatus CVE-2017-5754 VULN "PTI is needed to mitigate the vulnerability"
fi
else
if [ "$kpti_support" = 1 ]; then if [ "$kpti_support" = 1 ]; then
pvulnstatus CVE-2017-5754 OK "offline mode: PTI will mitigate the vulnerability if enabled at runtime" pstatus green YES
elif [ "$kpti_can_tell" = 1 ]; then
pstatus red NO
else else
pvulnstatus CVE-2017-5754 VULN "PTI is needed to mitigate the vulnerability" pstatus yellow UNKNOWN "couldn't read your kernel configuration nor System.map file"
fi fi
mount_debugfs
_info_nol "* PTI enabled and active: "
if [ "$opt_live" = 1 ]; then
if grep ^flags /proc/cpuinfo | grep -qw pti; then
# vanilla PTI patch sets the 'pti' flag in cpuinfo
kpti_enabled=1
elif grep ^flags /proc/cpuinfo | grep -qw kaiser; then
# kernel line 4.9 sets the 'kaiser' flag in cpuinfo
kpti_enabled=1
elif [ -e /sys/kernel/debug/x86/pti_enabled ]; then
# RedHat Backport creates a dedicated file, see https://access.redhat.com/articles/3311301
kpti_enabled=$(cat /sys/kernel/debug/x86/pti_enabled 2>/dev/null)
elif dmesg | grep -Eq 'Kernel/User page tables isolation: enabled|Kernel page table isolation enabled'; then
# if we can't find the flag, grep dmesg output
kpti_enabled=1
elif [ -r /var/log/dmesg ] && grep -Eq 'Kernel/User page tables isolation: enabled|Kernel page table isolation enabled' /var/log/dmesg; then
# if we can't find the flag in dmesg output, grep in /var/log/dmesg when readable
kpti_enabled=1
else
kpti_enabled=0
fi
if [ "$kpti_enabled" = 1 ]; then
pstatus green YES
else
pstatus red NO
fi
else
pstatus blue N/A "can't verify if PTI is enabled in offline mode"
fi
fi
# if we have the /sys interface, don't even check is_cpu_vulnerable ourselves, the kernel already does it
cve='CVE-2017-5754'
if [ "$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"
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"
else
pvulnstatus $cve VULN "PTI is needed to mitigate the vulnerability"
fi
fi
else
pvulnstatus $cve "$status" "$msg"
fi fi
} }