46 lines
1.8 KiB
Diff
46 lines
1.8 KiB
Diff
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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 7e23c00e809c1669676363962e2ef9df1bd2840b)
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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/nested.c | 3 +++
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1 file changed, 3 insertions(+)
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diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c
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index 049d3cbbee5a..3bd5c7d6716e 100644
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--- a/arch/x86/kvm/svm/nested.c
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+++ b/arch/x86/kvm/svm/nested.c
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@@ -147,6 +147,9 @@ void recalc_intercepts(struct vcpu_svm *svm)
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for (i = 0; i < MAX_INTERCEPT; i++)
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c->intercepts[i] |= g->intercepts[i];
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+
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+ vmcb_set_intercept(c, INTERCEPT_VMLOAD);
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+ vmcb_set_intercept(c, INTERCEPT_VMSAVE);
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}
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static void copy_vmcb_control_area(struct vmcb_control_area *dst,
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