From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-10.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8CDB7C433E8 for ; Mon, 27 Jul 2020 13:39:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6C1FB208E4 for ; Mon, 27 Jul 2020 13:39:50 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="E7SM65mZ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729112AbgG0Njt (ORCPT ); Mon, 27 Jul 2020 09:39:49 -0400 Received: from us-smtp-1.mimecast.com ([207.211.31.81]:33202 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1729110AbgG0Njq (ORCPT ); Mon, 27 Jul 2020 09:39:46 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1595857185; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=IXS0lkSpu6Sgs9lUnBVrdmTtxQyF0fd0pmeFbgzfAyE=; b=E7SM65mZpPI02pMCu9WG6QWfNU2UKOdbm3FuYEXFVHsY9u/NjnIs7n91rH6uS3JIptr5n7 tykgagoOU3Wt0myLEaFSh2OyUix8vBjiSry9pYt86q9RIjFk+v4w7B5KClwH8i0XfwncPi zFaJA4T/Link9ZSrKVBLeLCpL9lkcQw= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-317-EpdeGXJJPVWS2VuQk2p9ZA-1; Mon, 27 Jul 2020 09:39:43 -0400 X-MC-Unique: EpdeGXJJPVWS2VuQk2p9ZA-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 6CA0C106B245; Mon, 27 Jul 2020 13:39:42 +0000 (UTC) Received: from virtlab701.virt.lab.eng.bos.redhat.com (virtlab701.virt.lab.eng.bos.redhat.com [10.19.152.228]) by smtp.corp.redhat.com (Postfix) with ESMTP id E5D265D9F3; Mon, 27 Jul 2020 13:39:39 +0000 (UTC) From: Paolo Bonzini To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: vkuznets@redhat.com, aaronlewis@google.com Subject: [PATCH 2/3] KVM: nVMX: check for required but missing VMCS12 in KVM_SET_NESTED_STATE Date: Mon, 27 Jul 2020 09:39:33 -0400 Message-Id: <20200727133934.25482-3-pbonzini@redhat.com> In-Reply-To: <20200727133934.25482-1-pbonzini@redhat.com> References: <20200727133934.25482-1-pbonzini@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org A missing VMCS12 was not causing -EINVAL (it was just read with copy_from_user, so it is not a security issue, but it is still wrong). Test for VMCS12 validity and reject the nested state if a VMCS12 is required but not present. Signed-off-by: Paolo Bonzini --- arch/x86/kvm/vmx/nested.c | 13 ++++++++++--- arch/x86/kvm/vmx/nested.h | 5 +++++ .../kvm/x86_64/vmx_set_nested_state_test.c | 12 +++++++++++- 3 files changed, 26 insertions(+), 4 deletions(-) diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c index d4a4cec034d0..6a0e32a7418c 100644 --- a/arch/x86/kvm/vmx/nested.c +++ b/arch/x86/kvm/vmx/nested.c @@ -6108,9 +6108,16 @@ static int vmx_set_nested_state(struct kvm_vcpu *vcpu, if (ret) return ret; - /* Empty 'VMXON' state is permitted */ - if (kvm_state->size < sizeof(*kvm_state) + sizeof(*vmcs12)) - return 0; + /* Empty VMX data is permitted if no VMCS loaded */ + if (kvm_state->size < sizeof(*kvm_state) + sizeof(*vmcs12)) { + /* See vmx_has_valid_vmcs12. */ + if ((kvm_state->flags & KVM_STATE_NESTED_GUEST_MODE) || + (kvm_state->flags & KVM_STATE_NESTED_EVMCS) || + (kvm_state->hdr.vmx.vmcs12_pa != -1ull)) + return -EINVAL; + else + return 0; + } if (kvm_state->hdr.vmx.vmcs12_pa != -1ull) { if (kvm_state->hdr.vmx.vmcs12_pa == kvm_state->hdr.vmx.vmxon_pa || diff --git a/arch/x86/kvm/vmx/nested.h b/arch/x86/kvm/vmx/nested.h index 758bccc26cf9..197148d76b8f 100644 --- a/arch/x86/kvm/vmx/nested.h +++ b/arch/x86/kvm/vmx/nested.h @@ -47,6 +47,11 @@ static inline struct vmcs12 *get_shadow_vmcs12(struct kvm_vcpu *vcpu) return to_vmx(vcpu)->nested.cached_shadow_vmcs12; } +/* + * Note: the same condition is checked against the state provided by userspace + * in vmx_set_nested_state; if it is satisfied, the nested state must include + * the VMCS12. + */ static inline int vmx_has_valid_vmcs12(struct kvm_vcpu *vcpu) { struct vcpu_vmx *vmx = to_vmx(vcpu); diff --git a/tools/testing/selftests/kvm/x86_64/vmx_set_nested_state_test.c b/tools/testing/selftests/kvm/x86_64/vmx_set_nested_state_test.c index d14a34f1b018..94f28a657569 100644 --- a/tools/testing/selftests/kvm/x86_64/vmx_set_nested_state_test.c +++ b/tools/testing/selftests/kvm/x86_64/vmx_set_nested_state_test.c @@ -183,9 +183,19 @@ void test_vmx_nested_state(struct kvm_vm *vm) state->hdr.vmx.smm.flags = KVM_STATE_NESTED_SMM_GUEST_MODE; test_nested_state_expect_einval(vm, state); - /* Size must be large enough to fit kvm_nested_state and vmcs12. */ + /* + * Size must be large enough to fit kvm_nested_state and vmcs12 + * if VMCS12 physical address is set + */ + set_default_vmx_state(state, state_sz); + state->size = sizeof(*state); + state->flags = 0; + test_nested_state_expect_einval(vm, state); + set_default_vmx_state(state, state_sz); state->size = sizeof(*state); + state->flags = 0; + state->hdr.vmx.vmcs12_pa = -1; test_nested_state(vm, state); /* -- 2.26.2