From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932541AbdJJPbJ (ORCPT ); Tue, 10 Oct 2017 11:31:09 -0400 Received: from mail-wm0-f68.google.com ([74.125.82.68]:51692 "EHLO mail-wm0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932345AbdJJPbG (ORCPT ); Tue, 10 Oct 2017 11:31:06 -0400 X-Google-Smtp-Source: AOwi7QAl/fpA3oxGlPN4Kay1+JJUYHKA3cI0QuI348z/S27/31+Cd9h8E2/p2quGuv4t5FM1wtDhow== From: Paolo Bonzini To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: lprosek@redhat.com, ahonig@google.com Subject: [PATCH 1/2] KVM: nVMX: update last_nonleaf_level when initializing nested EPT Date: Tue, 10 Oct 2017 17:30:58 +0200 Message-Id: <1507649459-144559-2-git-send-email-pbonzini@redhat.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1507649459-144559-1-git-send-email-pbonzini@redhat.com> References: <1507649459-144559-1-git-send-email-pbonzini@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Ladi Prosek 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 Signed-off-by: Paolo Bonzini --- 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 106d4a029a8a..3c25f20115bc 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -4555,6 +4555,7 @@ 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); } -- 1.8.3.1