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Date: Mon, 23 Oct 2017 13:10:00 +0200
From: Christian Borntraeger <borntraeger@...ibm.com>
To: David Hildenbrand <david@...hat.com>, Paolo Bonzini
<pbonzini@...hat.com>,
linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Cc: kernel-hardening@...ts.openwall.com, Kees Cook <keescook@...omium.org>,
Radim Krčmář <rkrcmar@...hat.com>,
Christoffer Dall <christoffer.dall@...aro.org>,
Marc Zyngier <marc.zyngier@....com>, Cornelia Huck <cohuck@...hat.com>,
James Hogan <james.hogan@...tec.com>,
Paul Mackerras <paulus@...ba.org>
Subject: Re: [PATCH 0/2] KVM: fixes for the kernel-hardening tree
On 10/23/2017 11:52 AM, David Hildenbrand wrote:
> On 21.10.2017 01:25, Paolo Bonzini wrote:
>> Two KVM ioctls (KVM_GET/SET_CPUID2) directly access the cpuid_entries
>> field of struct kvm_vcpu_arch. Therefore, the new usercopy hardening
>> work in linux-next, which forbids copies from and to slab objects
>> unless they are from kmalloc or explicitly whitelisted, breaks KVM
>> completely.
>>
>> This series fixes it by adding the two new usercopy arguments
>> to kvm_init (more precisely to a new function kvm_init_usercopy,
>> while kvm_init passes zeroes as a default).
>>
>> There's also another broken ioctl, KVM_XEN_HVM_CONFIG, but it is
>> obsolete and not a big deal at all.
>>
>> I'm Ccing all submaintainers in case they have something similar
>> going on in their kvm_arch and kvm_vcpu_arch structs. KVM has a
>> pretty complex userspace API, so thorough with linux-next is highly
>> recommended.
>
> I assume on s390x, at least
>
> kvm_arch_vcpu_ioctl_get_one_reg() and
> kvm_arch_vcpu_ioctl_set_one_reg()
>
> have to be fixed.
>
> Christian, are you already looking into this?
Not yet. I am in preparation for travel.
>
>>
>> Many thanks to Thomas Gleixner for reporting this to me.
>>
>> Paolo
>>
>> Paolo Bonzini (2):
>> KVM: allow setting a usercopy region in struct kvm_vcpu
>> KVM: fix KVM_XEN_HVM_CONFIG ioctl
>>
>> arch/x86/include/asm/kvm_host.h | 3 +++
>> arch/x86/kvm/svm.c | 4 ++--
>> arch/x86/kvm/vmx.c | 4 ++--
>> arch/x86/kvm/x86.c | 17 ++++++++++++++---
>> include/linux/kvm_host.h | 13 +++++++++++--
>> virt/kvm/kvm_main.c | 13 ++++++++-----
>> 6 files changed, 40 insertions(+), 14 deletions(-)
>>
>
>
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