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cosmetic + v0.02

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Stéphane Lesimple 2018-01-07 16:22:30 +01:00
parent ef7c0d7ec5
commit 9ed1fcd98a
2 changed files with 27 additions and 22 deletions
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35
README.md
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@ -5,29 +5,34 @@ A simple shell script to tell if your Linux installation is vulnerable
against the 3 "speculative execution" CVEs:
CVE-2017-5753 bounds check bypass (Spectre Variant 1)
Impact: Kernel & all software
Mitigation: recompile software *and* kernel with a modified compiler that introduces the LFENCE opcode at the proper positions in the resulting code
Performance impact of the mitigation: negligible
- Impact: Kernel & all software
- Mitigation: recompile software *and* kernel with a modified compiler that introduces the LFENCE opcode at the proper positions in the resulting code
- Performance impact of the mitigation: negligible
CVE-2017-5715: branch target injection (Spectre Variant 2)
Impact: Kernel
Mitigation 1: new opcode via microcode update that should be used by up to date compilers to protect the BTB (by flushing indirect branch predictors)
Mitigation 2: introducing "retpoline" into compilers, and recompile software/OS with it
Performance impact of the mitigation: high for mitigation 1, medium for mitigation 2, depending on your CPU
- Impact: Kernel
- Mitigation 1: new opcode via microcode update that should be used by up to date compilers to protect the BTB (by flushing indirect branch predictors)
- Mitigation 2: introducing "retpoline" into compilers, and recompile software/OS with it
- Performance impact of the mitigation: high for mitigation 1, medium for mitigation 2, depending on your CPU
CVE-2017-5754: rogue data cache load (Meltdown)
Impact: Kernel
Mitigation: updated kernel (with PTI/KPTI patches), updating the kernel is enough
Performance impact of the mitigation: low to medium
- Impact: Kernel
- Mitigation: updated kernel (with PTI/KPTI patches), updating the kernel is enough
- Performance impact of the mitigation: low to medium
Example of the output of the script:
Spectre and Meltdown mitigation detection tool v0.01
```
$ sudo ./spectre-meltdown-checker.sh
Spectre and Meltdown mitigation detection tool v0.02
CVE-2017-5753 [bounds check bypass] aka 'Spectre Variant 1'
* Kernel recompiled with LFENCE opcode insertion: UNKNOWN (check not yet implemented)
> STATUS: UNKNOWN (not implemented, but real answer is most probably VULNERABLE at this stage)
* Kernel compiled with LFENCE opcode inserted at the proper places: NO (only 38 opcodes found, should be >= 60)
> STATUS: VULNERABLE
CVE-2017-5715 [branch target injection] aka 'Spectre Variant 2'
* Mitigation 1
@ -36,8 +41,8 @@ CVE-2017-5715 [branch target injection] aka 'Spectre Variant 2'
* IBRS enabled for Kernel space: NO
* IBRS enabled for User space: NO
* Mitigation 2
* Kernel recompiled with retpoline: UNKNOWN (check not yet implemented)
> STATUS: VULNERABLE (IBRS hardware + kernel support OR retpoline-compiled kernel are needed to mitigate the vulnerability)
* Kernel recompiled with retpolines: UNKNOWN (check not yet implemented)
> STATUS: VULNERABLE (IBRS hardware + kernel support OR retpolines-compiled kernel are needed to mitigate the vulnerability)
CVE-2017-5754 [rogue data cache load] aka 'Meltdown' aka 'Variant 3'
* Kernel supports Page Table Isolation (PTI): YES

14
spectre-meltdown-checker.sh
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@ -1,7 +1,7 @@
#! /bin/sh
# Spectre & Meltdown checker
# Stephane Lesimple, v0.00.01
VERSION=0.01
# Stephane Lesimple
VERSION=0.02
pstatus()
{
@ -81,11 +81,11 @@ elif ! which objdump >/dev/null 2>&1; then
pstatus yellow UNKNOWN "missing 'objdump' tool, please install it, usually it's in the binutils package"
else
nb_lfence=$(objdump -D "$vmlinux" | grep -wc lfence)
if [ "$nb_lfence" -lt 50 ]; then
pstatus red NO "only $nb_lfence lfence opcodes found, should be >= 50"
if [ "$nb_lfence" -lt 60 ]; then
pstatus red NO "only $nb_lfence opcodes found, should be >= 60"
status=1
else
pstatus green YES "$nb_lfence opcodes found, which is >= 50"
pstatus green YES "$nb_lfence opcodes found, which is >= 60"
status=2
fi
rm -f $vmlinux
@ -155,7 +155,7 @@ if [ "$mounted_debugfs" = 1 ]; then
fi
/bin/echo "* Mitigation 2"
/bin/echo -n "* Kernel recompiled with retpoline: "
/bin/echo -n "* Kernel recompiled with retpolines: "
pstatus yellow UNKNOWN "check not yet implemented"
/bin/echo -ne "> \033[46m\033[30mSTATUS:\033[0m "
@ -164,7 +164,7 @@ if grep -q AMD /proc/cpuinfo; then
elif [ "$ibrs_enabled" = 1 -o "$ibrs_enabled" = 2 ]; then
pstatus green "NOT VULNERABLE" "IBRS mitigates the vulnerability"
else
pstatus red VULNERABLE "IBRS hardware + kernel support OR retpoline-compiled kernel are needed to mitigate the vulnerability"
pstatus red VULNERABLE "IBRS hardware + kernel support OR retpolines-compiled kernel are needed to mitigate the vulnerability"
fi
# MELTDOWN