From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Ladi Prosek , Paolo Bonzini Subject: [PATCH 4.9 39/39] KVM: nVMX: update last_nonleaf_level when initializing nested EPT Date: Mon, 16 Oct 2017 18:16:35 +0200 Message-Id: <20171016161432.655316697@linuxfoundation.org> In-Reply-To: <20171016161429.968555175@linuxfoundation.org> References: <20171016161429.968555175@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Ladi Prosek 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: 155a97a3d7c78b46cef6f1a973c831bc5a4f82bb Signed-off-by: Ladi Prosek Signed-off-by: Paolo Bonzini Signed-off-by: Greg Kroah-Hartman --- arch/x86/kvm/mmu.c | 1 + 1 file changed, 1 insertion(+) --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -4169,6 +4169,7 @@ void kvm_init_shadow_ept_mmu(struct kvm_ 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); }