fix: mcepsc: fix logic error on non-speculative CPUs that prevented detection of MCEPSC immunity

pull/332/head
Stéphane Lesimple 3 years ago
parent 4993b04922
commit 6e799e8b01
  1. 4
      README.md
  2. 68
      spectre-meltdown-checker.sh

@ -15,7 +15,7 @@ A shell script to tell if your system is vulnerable against the several "specula
- CVE-2018-12127 [microarchitectural load port data sampling (MLPDS)] aka 'RIDL'
- CVE-2019-11091 [microarchitectural data sampling uncacheable memory (MDSUM)] aka 'RIDL'
- CVE-2019-11135 [TSX asynchronous abort] aka 'TAA' aka 'ZombieLoad V2'
- CVE-2018-12207 [iTLB Multihit] aka 'No eXcuses'
- CVE-2018-12207 [machine check exception on page size changes (MCEPSC)] aka 'No eXcuses' aka 'iTLB Multihit'
Supported operating systems:
- Linux (all versions, flavors and distros)
@ -153,7 +153,7 @@ docker run --rm --privileged -v /boot:/boot:ro -v /dev/cpu:/dev/cpu:ro -v /lib/m
- Mitigation: microcode update + kernel update making possible to protect various CPU internal buffers from unprivileged speculative access to data
- Performance impact of the mitigation: low to significant
**CVE-2018-12207** iTLB Multihit (No eXcuses)
**CVE-2018-12207** machine check exception on page size changes (No eXcuses, iTLB Multihit)
- Impact: Virtualization software and Virtual Machine Monitors
- Mitigation: disable hugepages use in hypervisor, or update hypervisor to benefit from mitigation

@ -286,7 +286,7 @@ cve2name()
CVE-2018-12127) echo "RIDL, microarchitectural load port data sampling (MLPDS)";;
CVE-2019-11091) echo "RIDL, microarchitectural data sampling uncacheable memory (MDSUM)";;
CVE-2019-11135) echo "ZombieLoad V2, TSX Asynchronous Abort (TAA)";;
CVE-2018-12207) echo "No eXcuses, iTLB Multihit";;
CVE-2018-12207) echo "No eXcuses, iTLB Multihit, machine check exception on page size changes (MCEPSC)";;
*) echo "$0: error: invalid CVE '$1' passed to cve2name()" >&2; exit 255;;
esac
}
@ -430,34 +430,6 @@ is_cpu_vulnerable()
_debug "is_cpu_vulnerable: intel family < 6 is immune to l1tf"
[ -z "$variantl1tf" ] && variantl1tf=immune
fi
# iTLB MultiHit
# commit f9aa6b73a407b714c9aac44734eb4045c893c6f7
if [ "$cpu_model" = 6 ]; then
if [ "$cpu_model" = "$INTEL_FAM6_ATOM_SALTWELL" ] || \
[ "$cpu_model" = "$INTEL_FAM6_ATOM_SALTWELL_TABLET" ] || \
[ "$cpu_model" = "$INTEL_FAM6_ATOM_SALTWELL_MID" ] || \
[ "$cpu_model" = "$INTEL_FAM6_ATOM_BONNELL" ] || \
[ "$cpu_model" = "$INTEL_FAM6_ATOM_BONNELL_MID" ] || \
[ "$cpu_model" = "$INTEL_FAM6_ATOM_SILVERMONT" ] || \
[ "$cpu_model" = "$INTEL_FAM6_ATOM_SILVERMONT_D" ] || \
[ "$cpu_model" = "$INTEL_FAM6_ATOM_SILVERMONT_MID" ] || \
[ "$cpu_model" = "$INTEL_FAM6_ATOM_AIRMONT" ] || \
[ "$cpu_model" = "$INTEL_FAM6_XEON_PHI_KNL" ] || \
[ "$cpu_model" = "$INTEL_FAM6_XEON_PHI_KNM" ] || \
[ "$cpu_model" = "$INTEL_FAM6_ATOM_AIRMONT_MID" ] || \
[ "$cpu_model" = "$INTEL_FAM6_ATOM_GOLDMONT" ] || \
[ "$cpu_model" = "$INTEL_FAM6_ATOM_GOLDMONT_D" ] || \
[ "$cpu_model" = "$INTEL_FAM6_ATOM_GOLDMONT_PLUS" ]; then
_debug "is_cpu_vulnerable: intel family 6 but model known to be immune to itlbmh"
[ -z "$variantitlbmh" ] && variantitlbmh=immune
else
_debug "is_cpu_vulnerable: intel family 6 is vuln to itlbmh"
variantitlbmh=vuln
fi
elif [ "$cpu_family" -lt 6 ]; then
_debug "is_cpu_vulnerable: intel family < 6 is immune to itlbmh"
[ -z "$variantitlbmh" ] && variantitlbmh=immune
fi
elif is_amd || is_hygon; then
# AMD revised their statement about variant2 => vulnerable
# https://www.amd.com/en/corporate/speculative-execution
@ -472,12 +444,10 @@ is_cpu_vulnerable()
_debug "is_cpu_vulnerable: cpu not affected by speculative store bypass so not vuln to variant4"
fi
variantl1tf=immune
variantitlbmh=immune
elif [ "$cpu_vendor" = CAVIUM ]; then
variant3=immune
variant3a=immune
variantl1tf=immune
variantitlbmh=immune
elif [ "$cpu_vendor" = ARM ]; then
# ARM
# reference: https://developer.arm.com/support/security-update
@ -566,8 +536,42 @@ is_cpu_vulnerable()
_debug "is_cpu_vulnerable: for cpu$i and so far, we have <$variant1> <$variant2> <$variant3> <$variant3a> <$variant4>"
done
variantl1tf=immune
variantitlbmh=immune
fi
# we handle iTLB Multihit here (not linked to is_specex_free)
if is_intel; then
# commit f9aa6b73a407b714c9aac44734eb4045c893c6f7
if [ "$cpu_family" = 6 ]; then
if [ "$cpu_model" = "$INTEL_FAM6_ATOM_SALTWELL" ] || \
[ "$cpu_model" = "$INTEL_FAM6_ATOM_SALTWELL_TABLET" ] || \
[ "$cpu_model" = "$INTEL_FAM6_ATOM_SALTWELL_MID" ] || \
[ "$cpu_model" = "$INTEL_FAM6_ATOM_BONNELL" ] || \
[ "$cpu_model" = "$INTEL_FAM6_ATOM_BONNELL_MID" ] || \
[ "$cpu_model" = "$INTEL_FAM6_ATOM_SILVERMONT" ] || \
[ "$cpu_model" = "$INTEL_FAM6_ATOM_SILVERMONT_D" ] || \
[ "$cpu_model" = "$INTEL_FAM6_ATOM_SILVERMONT_MID" ] || \
[ "$cpu_model" = "$INTEL_FAM6_ATOM_AIRMONT" ] || \
[ "$cpu_model" = "$INTEL_FAM6_XEON_PHI_KNL" ] || \
[ "$cpu_model" = "$INTEL_FAM6_XEON_PHI_KNM" ] || \
[ "$cpu_model" = "$INTEL_FAM6_ATOM_AIRMONT_MID" ] || \
[ "$cpu_model" = "$INTEL_FAM6_ATOM_GOLDMONT" ] || \
[ "$cpu_model" = "$INTEL_FAM6_ATOM_GOLDMONT_D" ] || \
[ "$cpu_model" = "$INTEL_FAM6_ATOM_GOLDMONT_PLUS" ]; then
_debug "is_cpu_vulnerable: intel family 6 but model known to be immune to itlbmh"
[ -z "$variant_itlbmh" ] && variant_itlbmh=immune
else
_debug "is_cpu_vulnerable: intel family 6 is vuln to itlbmh"
variant_itlbmh=vuln
fi
elif [ "$cpu_family" -lt 6 ]; then
_debug "is_cpu_vulnerable: intel family < 6 is immune to itlbmh"
[ -z "$variant_itlbmh" ] && variant_itlbmh=immune
fi
else
_debug "is_cpu_vulnerable: non-intel not vulnerable to itlbmh"
[ -z "$variant_itlbmh" ] && variant_itlbmh=immune
fi
_debug "is_cpu_vulnerable: temp results are <$variant1> <$variant2> <$variant3> <$variant3a> <$variant4> <$variantl1tf>"
[ "$variant1" = "immune" ] && variant1=1 || variant1=0
[ "$variant2" = "immune" ] && variant2=1 || variant2=0

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