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fix(vmm): revert to checking the running processes to detect a hypervisor

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More information available on #278
This commit is contained in:
Stéphane Lesimple 2019-05-05 19:57:59 +02:00
parent 1264b1c7a3
commit 4edb867def
1 changed files with 8 additions and 28 deletions
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36
spectre-meltdown-checker.sh
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@ -3854,37 +3854,17 @@ check_CVE_2018_3646_linux()
# a hypervisor, as this requires more mitigations
has_vmm=2
elif [ "$has_vmm" = -1 ]; then
# Assumed to be running on bare metal unless evidence of vm is found.
has_vmm=0
# test for presence of hypervisor flag - definitive if set
if [ -e "$procfs/cpuinfo" ] && grep ^flags "$procfs/cpuinfo" | grep -qw hypervisor; then
# Here, we want to know if we are hosting a hypervisor, and running some VMs on it.
# If we find no evidence that this is the case, assume we're not (to avoid scaring users),
# this can always be overridden with --vmm in any case.
# ... ignore SC2009 as `ps ax` is actually used as a fallback if `pgrep` isn't installed
# shellcheck disable=SC2009
if command -v pgrep >/dev/null 2>&1 && { pgrep qemu >/dev/null || pgrep kvm >/dev/null || pgrep libvirtd >/dev/null; }; then
has_vmm=1
_debug "hypervisor: present - hypervisor flag set in $procfs/cpuinfo"
else
_debug "hypervisor: unknown - hypervisor flag not set in $procfs/cpuinfo"
fi
# test for kernel detected hypervisor
dmesg_grep "Hypervisor detected:" ; ret=$?
if [ $ret -eq 0 ]; then
_debug "hypervisor: present - found in dmesg: $dmesg_grepped"
elif ps ax | grep -vw grep | grep -q -e '\<qemu' -e '/qemu' -e '<\kvm' -e '/kvm' -e '/libvirtd'; then
has_vmm=1
elif [ $ret -eq 2 ]; then
_debug "hypervisor: dmesg truncated"
fi
# test for kernel detected paravirtualization
dmesg_grep "Booting paravirtualized kernel on bare hardware" ; ret=$?
if [ $ret -eq 0 ]; then
_debug "hypervisor: not present (bare hardware)- found in dmesg: $dmesg_grepped"
elif [ $ret -eq 2 ]; then
_debug "hypervisor: dmesg truncated"
else
dmesg_grep "Booting paravirtualized kernel on" ; ret=$?
if [ $ret -eq 0 ]; then
_debug "hypervisor: present - found in dmesg: $dmesg_grepped"
has_vmm=1
elif [ $ret -eq 2 ]; then
_debug "hypervisor: dmesg truncated"
fi
has_vmm=0
fi
fi
if [ "$has_vmm" = 0 ]; then