From: David Hildenbrand <david@redhat.com> To: Paolo Bonzini <pbonzini@redhat.com>, Cornelia Huck <cohuck@redhat.com> Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org, kernel-hardening@lists.openwall.com, "Kees Cook" <keescook@chromium.org>, "Radim Krčmář" <rkrcmar@redhat.com>, "Christoffer Dall" <christoffer.dall@linaro.org>, "Marc Zyngier" <marc.zyngier@arm.com>, "Christian Borntraeger" <borntraeger@de.ibm.com>, "James Hogan" <james.hogan@imgtec.com>, "Paul Mackerras" <paulus@samba.org> Subject: Re: [PATCH 0/2] KVM: fixes for the kernel-hardening tree Date: Wed, 25 Oct 2017 11:45:21 +0200 [thread overview] Message-ID: <f942d9b4-6fde-267d-aa04-a64218b1391f@redhat.com> (raw) In-Reply-To: <6fbcdbac-a717-def4-1864-6426d58986fc@redhat.com> On 23.10.2017 16:15, Paolo Bonzini wrote: > On 23/10/2017 14:39, Cornelia Huck wrote: >> On Mon, 23 Oct 2017 11:52:51 +0200 >> David Hildenbrand <david@redhat.com> 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. >> >> At a glance, seems like it. >> >>> >>> Christian, are you already looking into this? >> >> I'm afraid I'm also busy with travel preparation/travel, so I'd be glad >> for any takers. > > Let's do a generic fix now, so that we don't need to rush the switch to > explicit whitelisting. You mean a arch specific fix (allow writes/reads to arch) or even more generic? Otherwise I can you send a patch to fix these two functions. > > Paolo > -- Thanks, David
WARNING: multiple messages have this Message-ID (diff)
From: David Hildenbrand <david@redhat.com> To: Paolo Bonzini <pbonzini@redhat.com>, Cornelia Huck <cohuck@redhat.com> Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org, kernel-hardening@lists.openwall.com, "Kees Cook" <keescook@chromium.org>, "Radim Krčmář" <rkrcmar@redhat.com>, "Christoffer Dall" <christoffer.dall@linaro.org>, "Marc Zyngier" <marc.zyngier@arm.com>, "Christian Borntraeger" <borntraeger@de.ibm.com>, "James Hogan" <james.hogan@imgtec.com>, "Paul Mackerras" <paulus@samba.org> Subject: [kernel-hardening] Re: [PATCH 0/2] KVM: fixes for the kernel-hardening tree Date: Wed, 25 Oct 2017 11:45:21 +0200 [thread overview] Message-ID: <f942d9b4-6fde-267d-aa04-a64218b1391f@redhat.com> (raw) In-Reply-To: <6fbcdbac-a717-def4-1864-6426d58986fc@redhat.com> On 23.10.2017 16:15, Paolo Bonzini wrote: > On 23/10/2017 14:39, Cornelia Huck wrote: >> On Mon, 23 Oct 2017 11:52:51 +0200 >> David Hildenbrand <david@redhat.com> 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. >> >> At a glance, seems like it. >> >>> >>> Christian, are you already looking into this? >> >> I'm afraid I'm also busy with travel preparation/travel, so I'd be glad >> for any takers. > > Let's do a generic fix now, so that we don't need to rush the switch to > explicit whitelisting. You mean a arch specific fix (allow writes/reads to arch) or even more generic? Otherwise I can you send a patch to fix these two functions. > > Paolo > -- Thanks, David
next prev parent reply other threads:[~2017-10-25 9:45 UTC|newest] Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top 2017-10-20 23:25 [PATCH 0/2] KVM: fixes for the kernel-hardening tree Paolo Bonzini 2017-10-20 23:25 ` [kernel-hardening] " Paolo Bonzini 2017-10-20 23:25 ` [PATCH 1/2] KVM: allow setting a usercopy region in struct kvm_vcpu Paolo Bonzini 2017-10-20 23:25 ` [kernel-hardening] " Paolo Bonzini 2017-10-21 14:53 ` Kees Cook 2017-10-21 14:53 ` [kernel-hardening] " Kees Cook 2017-10-20 23:25 ` [PATCH 2/2] KVM: fix KVM_XEN_HVM_CONFIG ioctl Paolo Bonzini 2017-10-20 23:25 ` [kernel-hardening] " Paolo Bonzini 2017-10-21 18:45 ` [PATCH] KVM: arm/arm64: Allow usercopy to vcpu->arch.ctxt and arm64 debug Christoffer Dall 2017-10-21 18:45 ` [kernel-hardening] " Christoffer Dall 2017-10-21 18:45 ` Christoffer Dall 2017-10-22 3:06 ` Kees Cook 2017-10-22 3:06 ` [kernel-hardening] " Kees Cook 2017-10-22 3:06 ` Kees Cook 2017-10-22 7:44 ` Christoffer Dall 2017-10-22 7:44 ` [kernel-hardening] " Christoffer Dall 2017-10-22 7:44 ` Christoffer Dall 2017-10-23 14:14 ` Paolo Bonzini 2017-10-23 14:14 ` [kernel-hardening] " Paolo Bonzini 2017-10-23 14:14 ` Paolo Bonzini 2017-10-23 14:49 ` Christoffer Dall 2017-10-23 14:49 ` [kernel-hardening] " Christoffer Dall 2017-10-23 14:49 ` Christoffer Dall 2017-10-23 19:40 ` Kees Cook 2017-10-23 19:40 ` [kernel-hardening] " Kees Cook 2017-10-23 19:40 ` Kees Cook 2017-10-23 21:06 ` R: " Paolo Bonzini 2017-10-23 21:06 ` [kernel-hardening] " Paolo Bonzini 2017-10-23 21:06 ` Paolo Bonzini 2017-10-22 7:48 ` [PATCH v2] " Christoffer Dall 2017-10-22 7:48 ` Christoffer Dall 2017-10-23 9:52 ` [PATCH 0/2] KVM: fixes for the kernel-hardening tree David Hildenbrand 2017-10-23 9:52 ` [kernel-hardening] " David Hildenbrand 2017-10-23 11:10 ` Christian Borntraeger 2017-10-23 11:10 ` [kernel-hardening] " Christian Borntraeger 2017-10-23 12:39 ` Cornelia Huck 2017-10-23 12:39 ` [kernel-hardening] " Cornelia Huck 2017-10-23 14:15 ` Paolo Bonzini 2017-10-23 14:15 ` [kernel-hardening] " Paolo Bonzini 2017-10-25 9:45 ` David Hildenbrand [this message] 2017-10-25 9:45 ` David Hildenbrand 2017-10-25 10:31 ` Christian Borntraeger 2017-10-25 10:31 ` [kernel-hardening] " Christian Borntraeger
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