update sources to Ubuntu-4.13.0-17.20

[pve-kernel.git] / patches / kernel-cves / CVE-2017-12188_0001-KVM-nVMX-update-last_nonleaf_level-when-initializing.patch

From 8da45fe7977a1866ea95d5d281485e6f139d75c8 Mon Sep 17 00:00:00 2001
From: Ladi Prosek <lprosek@redhat.com>
Date: Tue, 10 Oct 2017 17:30:58 +0200
Subject: [CVE-2017-12188 1/2] KVM: nVMX: update last_nonleaf_level when
 initializing nested EPT
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The function updates context->root_level but didn't call
update_last_nonleaf_level so the previous and potentially wrong value
was used for page walks.  For example, a zero value of last_nonleaf_level
would allow a potential out-of-bounds access in arch/x86/mmu/paging_tmpl.h's
walk_addr_generic function (CVE-2017-12188).

Fixes: 155a97a3d7c78b46cef6f1a973c831bc5a4f82bb
Signed-off-by: Ladi Prosek <lprosek@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>
---
 arch/x86/kvm/mmu.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 56e68dfac974..ca0112742343 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -4459,6 +4459,7 @@ void kvm_init_shadow_ept_mmu(struct kvm_vcpu *vcpu, bool execonly,
 
 	update_permission_bitmask(vcpu, context, true);
 	update_pkru_bitmask(vcpu, context, true);
+	update_last_nonleaf_level(vcpu, context);
 	reset_rsvds_bits_mask_ept(vcpu, context, execonly);
 	reset_ept_shadow_zero_bits_mask(vcpu, context, execonly);
 }
-- 
2.14.1