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enh: downfall: detect kernel mitigation without sysfs

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This commit is contained in:
Stéphane Lesimple 2023-08-11 17:17:06 +02:00
parent aca4e2a9b1
commit dbe208fc48
1 changed files with 20 additions and 7 deletions
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27
spectre-meltdown-checker.sh
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@ -6229,17 +6229,30 @@ check_CVE_2022_40982_linux() {
fi
if [ -n "$kernel_gds" ]; then
_info_nol "* Is the kernel mitigation active: "
_info_nol "* Kernel has disabled AVX as a mitigation: "
# Check dmesg message to see whether AVX has been disabled
dmesg_grep 'Microcode update needed! Disabling AVX as mitigation'; ret=$?
if [ $ret -eq 2 ]; then
pstatus yellow UNKNOWN "dmesg truncated, AVX mitigation detection will be unreliable. Please reboot and relaunch this script"
elif [ $ret -eq 0 ]; then
kernel_avx_disabled="AVX disabled by the kernel"
dmesg_grep 'Microcode update needed! Disabling AVX as mitigation'; dmesgret=$?
if [ $dmesgret -eq 0 ]; then
kernel_avx_disabled="AVX disabled by the kernel (dmesg)"
pstatus green YES "$kernel_avx_disabled"
elif [ "$has_avx2" = 0 ]; then
# Find out by ourselves
# cpuinfo says we don't have AVX2, query
# the CPU directly about AVX2 support
read_cpuid 0x7 0x0 $EBX 5 1 1; ret=$?
if [ $ret -eq $READ_CPUID_RET_OK ]; then
kernel_avx_disabled="AVX disabled by the kernel (cpuid)"
pstatus green YES "$kernel_avx_disabled"
elif [ $ret -eq $READ_CPUID_RET_KO ]; then
pstatus yellow NO "CPU doesn't support AVX"
elif [ $dmesgret -eq 2 ]; then
pstatus yellow UNKNOWN "dmesg truncated, can't tell whether mitigation is active, please reboot and relaunch this script"
else
pstatus yellow UNKNOWN "No sign of mitigation in dmesg and couldn't read cpuid info"
fi
else
pstatus red NO "No trace of AVX mitigation in dmesg"
pstatus yellow NO "AVX support is enabled"
fi
fi