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Commit 28955b03 authored by Ladi Prosek's avatar Ladi Prosek Committed by Greg Kroah-Hartman
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KVM: nVMX: update last_nonleaf_level when initializing nested EPT 



commit fd19d3b45164466a4adce7cbff448ba9189e1427 upstream.

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: 155a97a3
Signed-off-by: default avatarLadi Prosek <lprosek@redhat.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent fb6da44f

arch/x86/kvm/mmu.c

+1 −0
Original line number Diff line number Diff line
@@ -4169,6 +4169,7 @@ 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);

}