IMO You first need to provide source for your spectre-meltdown checker, like any app of this type it's important to understand how it works and its limitations, possibly leading to false positives or ineffectiveness. Personally, I prefer the following It was one of the first tools available and the author seems to be reasonably conscientious about keeping his tool up to date.. It also doesn't hurt that it's open source and he describes what his tool does. https://github.com/speed47/spectre-meltdown-checker As for Spectre and Meltdown specifically... It's my understanding that openSUSE installs microcode patches during every bootup including Spectre and Meltdown mitigations. I don't know if simply booting an updated machine is sufficient to address the specific vulnerability you want to patch but in part that is what the vulnerability checker is supposed to tell you. Note also that regarding Meltdown and Spectre (more importantly the latter), the best first step to address these vulnerabilities is to be using a CPU shipped sometime between February 2018 and today, only those processors can be patched "properly." Once patched, it's my understanding that Meltdown and Spectre just won't work. Any earlier CPU cannot be properly patched, the only thing that can be done is to mitigate by blocking attack vectors as they are discovered. HTH and that is the best of my understanding, Tony On Sun, Apr 14, 2019 at 9:02 PM PGNet Dev wrote:

Following along at

CVE-2018-3646 Common Vulnerabilities and Exposures https://www.suse.com/security/cve/CVE-2018-3646/

&

Security Vulnerability: Spectre Variant 4 (Speculative Store Bypass) aka CVE-2018-3639. https://www.suse.com/support/kb/doc/?id=7022937

piecing together a number of other posts, and noting

https://lists.opensuse.org/opensuse-security-announce/2018-12/msg00073.html

An update that solves 9 vulnerabilities and has four fixes is now available. This update for xen fixes the following issues:

Update to Xen 4.10.2 bug fix release (bsc#1027519). ... - CVE-2018-3646: Mitigations for VMM aspects of L1 Terminal Fault (XSA-273) (bsc#1091107)

which references,

Bug 1091107 - VUL-0: CVE-2018-3646: xen: L1 Terminal Fault -VMM (XSA-273) https://bugzilla.suse.com/show_bug.cgi?id=1091107 ==> Status: RESOLVED FIXED

on

uname -rm 5.0.7-lp150.5.g012b5f1-default x86_64

lsb_release -rd Description: openSUSE Leap 15.0 Release: 15.0

grep "model name" /proc/cpuinfo | head -n 1 model name : Intel(R) Xeon(R) CPU E3-1220 v3 @ 3.10GHz

booting a Xen Dom0 host,

dmesg | grep -i "xen version" [ 1.188399] Xen version: 4.12.0_09-lp150.640 (preserve-AD)

In my grub cfg,

GRUB_CMDLINE_LINUX_XEN_REPLACE="... spectre_v2=retpoline,generic spec_store_bypass_disable=on ..." GRUB_CMDLINE_XEN="... spec-ctrl=ssbd,l1d-flush=true pv-l1tf=dom0=true,domu=true smt=true ucode=scan ..."

Updating microcode in Xen environments https://www.suse.com/support/kb/doc/?id=7022546

after grub re-config & mkinitrd, then reboot,

per

Updating microcode in Xen environments https://www.suse.com/support/kb/doc/?id=7022546

verifying,

egrep "family|model|stepping" /proc/cpuinfo -m 4 cpu family : 6 model : 60 model name : Intel(R) Xeon(R) CPU E3-1220 v3 @ 3.10GHz stepping : 3

in hex,

[cpu family]-[model]-[stepping] === 06-3C-03

rpm -qa | grep -i ucode-intel ucode-intel-20190312-lp150.3.1.x86_64

rpm -ql ucode-intel | grep -i 06-3C-03 /lib/firmware/intel-ucode/06-3c-03

lsinitrd /boot/initrd-5.0.7-lp150.5.g012b5f1-default Image: /boot/initrd-5.0.7-lp150.5.g012b5f1-default: 18M ======================================================================== Early CPIO image ======================================================================== drwxr-xr-x 3 root root 0 Apr 14 20:15 . -rw-r--r-- 1 root root 2 Apr 14 20:15 early_cpio drwxr-xr-x 3 root root 0 Apr 14 20:15 kernel drwxr-xr-x 3 root root 0 Apr 14 20:15 kernel/x86 drwxr-xr-x 2 root root 0 Apr 14 20:15 kernel/x86/microcode -rw-r--r-- 1 root root 23552 Apr 14 20:15 kernel/x86/microcode/GenuineIntel.bin ======================================================================== Version: dracut-044-lp150.14.27.1

grep -m1 microcode /proc/cpuinfo microcode : 0x25

in serial log

(XEN) [00000027c847dc37] Xen version 4.12.0_09-lp150.640 (abuild@suse.de) (gcc (SUSE Linux) 8.3.1 20190305 [gcc-8-branch revi sion 269383]) debug=n Thu Apr 11 22:29:39 UTC 2019 (XEN) [00000027cb3e1267] Latest ChangeSet: (XEN) [00000027cbff3231] Bootloader: EFI (XEN) [00000027ccb72e3d] Command line: dom0_mem=4016M,max:4096M bootscrub=false dom0_max_vcpus=4 spec-ctrl=ssbd,l1d-flush=true pv-l1tf=dom0=true,domu=true smt=true com1=115200,8n1,pci console=com1,vga console_timestamps console_to_ring conring_size=64 sched=credit2 reboot=acpi ucode=scan log_buf_len=16M loglvl=warning guest_loglvl=none/warning noreboot=false iommu=verbose ... (XEN) [00000028c099c50b] Speculative mitigation facilities: (XEN) [00000028c19f6e50] Hardware features: IBRS/IBPB STIBP L1D_FLUSH SSBD (XEN) [00000028c2f57689] Compiled-in support: INDIRECT_THUNK SHADOW_PAGING (XEN) [00000028c445abaf] Xen settings: BTI-Thunk RETPOLINE, SPEC_CTRL: IBRS- SSBD+, Other: IBPB L1D_FLUSH (XEN) [00000028c61da08b] L1TF: believed vulnerable, maxphysaddr L1D 46, CPUID 39, Safe address 8000000000 (XEN) [00000028c7f67494] Support for HVM VMs: MSR_SPEC_CTRL RSB EAGER_FPU (XEN) [00000028c94630dc] Support for PV VMs: MSR_SPEC_CTRL RSB EAGER_FPU (XEN) [00000028ca92b21c] XPTI (64-bit PV only): Dom0 enabled, DomU enabled (with PCID) (XEN) [00000028cc1cfa07] PV L1TF shadowing: Dom0 enabled, DomU enabled

then,

cd /sys/devices/system/cpu/vulnerabilities/ for f in $(ls); do echo -e "\n$f"; cat $f; done

l1tf Mitigation: PTE Inversion

meltdown Unknown (XEN PV detected, hypervisor mitigation required)

spec_store_bypass Mitigation: Speculative Store Bypass disabled

spectre_v1 Mitigation: __user pointer sanitization

spectre_v2 Mitigation: Full generic retpoline, IBPB: conditional, IBRS_FW, STIBP: conditional, RSB filling

BUT, checking with

spectre-meltdown-checker.sh

still returns "STATUS: VULNERABLE",

... CVE-2018-3646 aka 'Foreshadow-NG (VMM), L1 terminal fault' * Information from the /sys interface: * This system is a host running an hypervisor: YES * Mitigation 1 (KVM) * EPT is disabled: N/A (the kvm_intel module is not loaded) * Mitigation 2 * L1D flush is supported by kernel: YES (found flush_l1d in kernel image) * L1D flush enabled: UNKNOWN (unrecognized mode) * Hardware-backed L1D flush supported: NO (flush will be done in software, this is slower) * Hyper-Threading (SMT) is enabled: YES > STATUS: VULNERABLE (disable EPT or enabled L1D flushing to mitigate the vulnerability) ...

Since I'm on Xen, 'Mitigation 1' isn't an option.

Two things catch my attention:

(1) L1D flush enabled: UNKNOWN (unrecognized mode)

Not sure yet why I'm seeing UNKNOWN here,

&

(2) Hardware-backed L1D flush supported: NO

even though

(XEN) [00000028c19f6e50] Hardware features: IBRS/IBPB STIBP L1D_FLUSH SSBD ^^^^^^^^^

What's missing in my config to mitigate/remove the CVE-2018-3646 vulnerability?

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