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pti-rem
Guru
Joined: 14 Oct 2011
Posts: 490
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 Posted: Tue Mar 23, 2021 10:50 am Post subject: Vulnérabilités CPU : que faire de bien ? |
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Bonjour,
Je constate que ma machine est vulnérable pour certaines failles du CPU :
| Code: | rem@n73sm ~ $ uname -r
4.19.97-gentoo
rem@n73sm ~ $ lscpu | grep -e CPU -e Vulnerability
Nom de modèle : Intel(R) Core(TM) i7-2670QM CPU @ 2.20GHz
Vulnerability Itlb multihit: KVM: Mitigation: Split huge pages
Vulnerability L1tf: Mitigation; PTE Inversion; VMX conditional cache flushes, SMT vulnerable
Vulnerability Mds: Vulnerable: Clear CPU buffers attempted, no microcode; SMT vulnerable
Vulnerability Meltdown: Mitigation; PTI
Vulnerability Spec store bypass: Vulnerable
Vulnerability Spectre v1: Mitigation; usercopy/swapgs barriers and __user pointer sanitization
Vulnerability Spectre v2: Mitigation; Full generic retpoline, STIBP disabled, RSB filling
Vulnerability Tsx async abort: Not affected
rem@n73sm ~ $ |
| Code: | rem@n73sm ~ $ cat /sys/devices/system/cpu/vulnerabilities/mds
Vulnerable: Clear CPU buffers attempted, no microcode; SMT vulnerable
rem@n73sm ~ $ |
Est-ce que je peux faire quelque chose pour améliorer cette situation ?
J'ai lu rapidement https://www.kernel.org/doc/html/latest/admin-guide/hw-vuln/mds.html
et je me demande si c'est une bonne chose de désactiver SMT avec l'option d'amorçage mds=full,nosmt ?
Je n'ai rien lu encore sur Spec store bypass.
Merci |
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xaviermiller
Bodhisattva
Joined: 23 Jul 2004
Posts: 8722
Location: ~Brussels - Belgique
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| Posted: Tue Mar 23, 2021 11:02 am Post subject: |
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Bonjour,
As-tu intégré le microcode à jour dans ton noyau ?
voir https://wiki.gentoo.org/wiki/Intel-microcode
Ensuite, relance le test pour voir si toutes les failles ont été corrigées.
_________________
Kind regards,
Xavier Miller |
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pti-rem
Guru
Joined: 14 Oct 2011
Posts: 490
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| Posted: Tue Mar 23, 2021 11:39 am Post subject: |
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Les options du noyau étaient bien mises pour sys-firmware/intel-microcode
| Code: | rem@n73sm ~ $ zcat /proc/config.gz | grep -e CONFIG_BLK_DEV_INITRD -e CONFIG_MICROCODE -e CONFIG_MICROCODE_INTEL
CONFIG_BLK_DEV_INITRD=y
CONFIG_MICROCODE=y
CONFIG_MICROCODE_INTEL=y
CONFIG_MICROCODE_AMD=y
CONFIG_MICROCODE_OLD_INTERFACE=y
rem@n73sm ~ $ |
Je n'avais pas mis le drapeau initramfs pour sys-firmware/intel-microcode
Le microcode /boot/intel-uc.img a été automatiquement détecté lors de l'exécution de grub-mkconfig
| Code: | rem@n73sm ~ $ dmesg | head -n 1
[ 0.000000] microcode: microcode updated early to revision 0x2f, date = 2019-02-17
rem@n73sm ~ $ lscpu | grep Vulnerability
Vulnerability Itlb multihit: KVM: Mitigation: Split huge pages
Vulnerability L1tf: Mitigation; PTE Inversion; VMX conditional cache flushes, SMT vulnerable
Vulnerability Mds: Mitigation; Clear CPU buffers; SMT vulnerable
Vulnerability Meltdown: Mitigation; PTI
Vulnerability Spec store bypass: Mitigation; Speculative Store Bypass disabled via prctl and seccomp
Vulnerability Spectre v1: Mitigation; usercopy/swapgs barriers and __user pointer sanitization
Vulnerability Spectre v2: Mitigation; Full generic retpoline, IBPB conditional, IBRS_FW, STIBP conditional, RSB filling
Vulnerability Tsx async abort: Not affected
rem@n73sm ~ $ |
| Code: | rem@n73sm ~ $ cat /sys/devices/system/cpu/vulnerabilities/mds
Mitigation: Clear CPU buffers; SMT vulnerable
rem@n73sm ~ $ |
J'ai bien envie de désactiver SMT !
Ça va ralentir la machine ?
Merci Xavier  |
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pti-rem
Guru
Joined: 14 Oct 2011
Posts: 490
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| Posted: Tue Mar 23, 2021 11:54 am Post subject: |
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| Code: | rem@n73sm ~ $ dmesg | head -n 3
[ 0.000000] microcode: microcode updated early to revision 0x2f, date = 2019-02-17
[ 0.000000] Linux version 4.19.97-gentoo (root@n73sm) (gcc version 9.2.0 (Gentoo 9.2.0-r2 p3)) #2 SMP Mon Feb 3 07:13:03 CET 2020
[ 0.000000] Command line: BOOT_IMAGE=/boot/vmlinuz-4.19.97-gentoo root=UUID=b56ef48b-982a-499d-b02d-4442ac784b8a ro acpi_osi=Linux mds=full,nosmt quiet
rem@n73sm ~ $ |
| Code: | rem@n73sm ~ $ lscpu | grep Vulnerability
Vulnerability Itlb multihit: KVM: Mitigation: Split huge pages
Vulnerability L1tf: Mitigation; PTE Inversion; VMX conditional cache flushes, SMT disabled
Vulnerability Mds: Mitigation; Clear CPU buffers; SMT disabled
Vulnerability Meltdown: Mitigation; PTI
Vulnerability Spec store bypass: Mitigation; Speculative Store Bypass disabled via prctl and seccomp
Vulnerability Spectre v1: Mitigation; usercopy/swapgs barriers and __user pointer sanitization
Vulnerability Spectre v2: Mitigation; Full generic retpoline, IBPB conditional, IBRS_FW, RSB filling
Vulnerability Tsx async abort: Not affected
rem@n73sm ~ $ |
| Code: | rem@n73sm ~ $ cat /sys/devices/system/cpu/vulnerabilities/mds
Mitigation: Clear CPU buffers; SMT disabled
rem@n73sm ~ $ |
Je verrai bien à l'usage.
Je me sens plus détendu tout d'un coup !
Comment j'ai pu passer à côté de ça, depuis le temps... |
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Skwal
Apprentice
Joined: 07 Jun 2019
Posts: 154
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| Posted: Mon Mar 29, 2021 1:33 pm Post subject: |
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Bonjour,
Merci pti-rem ! 
Suite à ton message je découvre le microcode, je ne m'y était pas spécialement intérresssé, et suis en train de le mettre en place.
Ca pourrait expliquer et réparer certains problèmes:
| Code: | ╰─ lscpu | grep -e CPU -e Vulnerability
Nom de modèle : Intel(R) Core(TM) i5-6400T CPU @ 2.20GHz
Vulnerability Itlb multihit: Processor vulnerable
Vulnerability L1tf: Mitigation; PTE Inversion
Vulnerability Mds: Vulnerable: Clear CPU buffers attempted, no microcode; SMT disabled
Vulnerability Meltdown: Mitigation; PTI
Vulnerability Spec store bypass: Vulnerable
Vulnerability Spectre v1: Mitigation; usercopy/swapgs barriers and __user pointer sanitization
Vulnerability Spectre v2: Mitigation; Full generic retpoline, STIBP disabled, RSB filling
Vulnerability Srbds: Vulnerable: No microcode
Vulnerability Tsx async abort: Not affected
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Cordialement, Skwal. |
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