f290af2cd5
from ubuntu-focal upstream/master-next Signed-off-by: Stoiko Ivanov <s.ivanov@proxmox.com> Signed-off-by: Wolfgang Bumiller <w.bumiller@proxmox.com>
46 lines
1.8 KiB
Diff
46 lines
1.8 KiB
Diff
From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
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From: Maxim Levitsky <mlevitsk@redhat.com>
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Date: Thu, 29 Jul 2021 18:37:38 +0300
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Subject: [PATCH] UBUNTU: SAUCE: KVM: nSVM: always intercept VMLOAD/VMSAVE when
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nested
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If L1 disables VMLOAD/VMSAVE intercepts, and doesn't enable
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Virtual VMLOAD/VMSAVE (currently not supported for the nested hypervisor),
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then VMLOAD/VMSAVE must operate on the L1 physical memory, which is only
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possible by making L0 intercept these instructions.
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Failure to do so allowed the nested guest to run VMLOAD/VMSAVE unintercepted,
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and thus read/write portions of the host physical memory.
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This fixes CVE-2021-3656, which was discovered by Maxim Levitsky and
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Paolo Bonzini.
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Fixes: 89c8a4984fc9 ("KVM: SVM: Enable Virtual VMLOAD VMSAVE feature")
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Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
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Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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CVE-2021-3656
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Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
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Acked-by: Stefan Bader <stefan.bader@canonical.com>
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Acked-by: Ben Romer <benjamin.romer@canonical.com>
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Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
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(cherry picked from commit 001ba8ebae0d2489b3e671b231daed4ad6f558d2)
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Signed-off-by: Stoiko Ivanov <s.ivanov@proxmox.com>
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---
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arch/x86/kvm/svm.c | 3 +++
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1 file changed, 3 insertions(+)
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diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
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index be8a017be58b..3b1b57521d8b 100644
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--- a/arch/x86/kvm/svm.c
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+++ b/arch/x86/kvm/svm.c
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@@ -516,6 +516,9 @@ static void recalc_intercepts(struct vcpu_svm *svm)
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c->intercept_dr = h->intercept_dr | g->intercept_dr;
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c->intercept_exceptions = h->intercept_exceptions | g->intercept_exceptions;
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c->intercept = h->intercept | g->intercept;
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+
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+ c->intercept |= (1ULL << INTERCEPT_VMLOAD);
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+ c->intercept |= (1ULL << INTERCEPT_VMSAVE);
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}
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static inline struct vmcb *get_host_vmcb(struct vcpu_svm *svm)
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