linux-kernel - Re: [PATCH 2/2] KVM: x86: Forbid KVM_SET_CPUID{,2} after KVM

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <5505d731-cf87-9662-33f3-08844d92877c@redhat.com>
Date:   Fri, 7 Jan 2022 19:15:43 +0100
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     Vitaly Kuznetsov <vkuznets@...hat.com>,
        Igor Mammedov <imammedo@...hat.com>
Cc:     kvm@...r.kernel.org, Sean Christopherson <seanjc@...gle.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/2] KVM: x86: Forbid KVM_SET_CPUID{,2} after KVM_RUN

On 1/7/22 10:02, Vitaly Kuznetsov wrote:
> 
> I'm again leaning towards an allowlist and currently I see only two
> candidates:
> 
> CPUID.01H.EBX bits 31:24 (initial LAPIC id)
> CPUID.0BH.EDX (x2APIC id)
> 
> Anything else I'm missing?

I would also ignore completely CPUID leaves 03H, 04H, 0BH, 80000005h, 
80000006h, 8000001Dh, 8000001Eh (cache and processor topology), just to 
err on the safe side.

We could change kvm_find_cpuid_entry to WARN if any of those leaves are 
passed.

Paolo