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fix(variant4): whitelist from common.c::cpu_no_spec_store_bypass (#202)

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* variant4 from common.c::cpu_no_spec_store_bypass

Variant 4 - Add function to 'whitelist' the hand-full of CPUs unaffected by speculative store bypass. 

This would allow improved determination of variant 4 status ( #189 ) of immune CPUs while waiting for the 4.17/stable patches to be backported to distro kernels.

Source of cpu list : https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/arch/x86/kernel/cpu/common.c#n945)
Modeled after is_cpu_specex_free()

* amd families fix

amd families are reported by parse_cpu_details() in decimal

* remove duplicates

Only list processors which speculate and are immune to variant 4.
Avoids duplication with non-speculating CPUs listed in is_cpu_specex_free()
This commit is contained in:
Rob Gill 2018-05-27 23:14:29 +10:00 committed by Stéphane Lesimple
parent 17a3488505
commit 5962d20ba7
1 changed files with 53 additions and 0 deletions
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53
spectre-meltdown-checker.sh
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@ -306,6 +306,10 @@ is_cpu_vulnerable()
variant4=immune
_debug "is_cpu_vulnerable: SSB_NO is set so not vuln to variant4"
fi
if is_cpu_ssb_free; then
[ -z "$variant4" ] && variant4=immune
_debug "is_cpu_vulnerable: cpu not affected by speculative store bypass so not vuln to variant4"
fi
elif is_amd; then
# AMD revised their statement about variant2 => vulnerable
# https://www.amd.com/en/corporate/speculative-execution
@ -315,6 +319,10 @@ is_cpu_vulnerable()
# https://www.amd.com/en/corporate/security-updates
# "We have not identified any AMD x86 products susceptible to the Variant 3a vulnerability in our analysis to-date."
[ -z "$variant3a" ] && variant3a=immune
if is_cpu_ssb_free; then
[ -z "$variant4" ] && variant4=immune
_debug "is_cpu_vulnerable: cpu not affected by speculative store bypass so not vuln to variant4"
fi
elif [ "$cpu_vendor" = ARM ]; then
# ARM
# reference: https://developer.arm.com/support/security-update
@ -432,6 +440,51 @@ is_cpu_specex_free()
return 1
}
is_cpu_ssb_free()
{
# return true (0) if the CPU isn't affected by speculative store bypass, false (1) if it does.
# if it's not in the list we know, return false (1).
# source1: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/arch/x86/kernel/cpu/common.c#n945
# source2: https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git/tree/arch/x86/kernel/cpu/common.c
# Only list CPUs that speculate but are immune, to avoid duplication of cpus listed in is_cpu_specex_free()
#{ X86_VENDOR_INTEL, 6, INTEL_FAM6_ATOM_SILVERMONT1 },
#{ X86_VENDOR_INTEL, 6, INTEL_FAM6_ATOM_AIRMONT },
#{ X86_VENDOR_INTEL, 6, INTEL_FAM6_ATOM_SILVERMONT2 },
#{ X86_VENDOR_INTEL, 6, INTEL_FAM6_ATOM_MERRIFIELD },
#{ X86_VENDOR_INTEL, 6, INTEL_FAM6_CORE_YONAH },
#{ X86_VENDOR_INTEL, 6, INTEL_FAM6_XEON_PHI_KNL },
#{ X86_VENDOR_INTEL, 6, INTEL_FAM6_XEON_PHI_KNM },
#{ X86_VENDOR_AMD, 0x12, },
#{ X86_VENDOR_AMD, 0x11, },
#{ X86_VENDOR_AMD, 0x10, },
#{ X86_VENDOR_AMD, 0xf, },
parse_cpu_details
if is_intel; then
if [ "$cpu_family" = 6 ]; then
if [ "$cpu_model" = "$INTEL_FAM6_ATOM_AIRMONT" ] || \
[ "$cpu_model" = "$INTEL_FAM6_ATOM_SILVERMONT1" ] || \
[ "$cpu_model" = "$INTEL_FAM6_ATOM_SILVERMONT2" ] || \
[ "$cpu_model" = "$INTEL_FAM6_ATOM_MERRIFIELD" ]; then
return 0
elif [ "$cpu_model" = "$INTEL_FAM6_CORE_YONAH" ] || \
[ "$cpu_model" = "$INTEL_FAM6_XEON_PHI_KNL" ] || \
[ "$cpu_model" = "$INTEL_FAM6_XEON_PHI_KNM" ]; then
return 0
fi
fi
fi
if is_amd; then
if [ "$cpu_family" = "18" ] || \
[ "$cpu_family" = "17" ] || \
[ "$cpu_family" = "16" ] || \
[ "$cpu_family" = "15" ]; then
return 0
fi
fi
[ "$cpu_family" = 4 ] && return 0
return 1
}
show_header()
{
_info "Spectre and Meltdown mitigation detection tool v$VERSION"