From patchwork Fri Jul 16 11:58:51 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vitaly Kuznetsov X-Patchwork-Id: 12382059 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=-13.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham 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 EAE55C07E95 for ; Fri, 16 Jul 2021 12:01:19 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 855E1613E9 for ; Fri, 16 Jul 2021 12:01:19 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 855E1613E9 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:58716 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1m4MWs-00064O-Er for qemu-devel@archiver.kernel.org; Fri, 16 Jul 2021 08:01:18 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:39542) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1m4MUe-0003TV-K8 for qemu-devel@nongnu.org; Fri, 16 Jul 2021 07:59:01 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:57177) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1m4MUc-0004le-Hh for qemu-devel@nongnu.org; Fri, 16 Jul 2021 07:59:00 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1626436737; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=UhQYb2x4NIX908cRk1SvJjhhUbKkvXuUfwDK6FTzTvM=; b=enf2/kDr/+zY1xzu/VBdkCCJSiHAlNoWXnp8CAj/hJWsikxAma4Um7iiJJb1EjiqXuAws5 kUxZC41VJSXqZnhwNbVhAlhw6YsiJWkgj2/KeZaoEqoHIWQ1B9qHsIJdejSB7JxnnCsjL7 /gGLc2fozCBP71fttnzXG5t3KrtvxE4= 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-334-68SLks1aNA-2Zp2vvOuolA-1; Fri, 16 Jul 2021 07:58:56 -0400 X-MC-Unique: 68SLks1aNA-2Zp2vvOuolA-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 641741018721; Fri, 16 Jul 2021 11:58:55 +0000 (UTC) Received: from vitty.brq.redhat.com (unknown [10.40.195.55]) by smtp.corp.redhat.com (Postfix) with ESMTP id 49739604CD; Fri, 16 Jul 2021 11:58:53 +0000 (UTC) From: Vitaly Kuznetsov To: qemu-devel@nongnu.org, Eduardo Habkost Subject: [PATCH 1/2] i386: assert 'cs->kvm_state' is not null Date: Fri, 16 Jul 2021 13:58:51 +0200 Message-Id: <20210716115852.418293-1-vkuznets@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=vkuznets@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Received-SPF: pass client-ip=170.10.133.124; envelope-from=vkuznets@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -34 X-Spam_score: -3.5 X-Spam_bar: --- X-Spam_report: (-3.5 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.7, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Peter Maydell , Paolo Bonzini , Marcelo Tosatti , Igor Mammedov Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Coverity reports potential NULL pointer dereference in get_supported_hv_cpuid_legacy() when 'cs->kvm_state' is NULL. While 'cs->kvm_state' can indeed be NULL in hv_cpuid_get_host(), kvm_hyperv_expand_features() makes sure that it only happens when KVM_CAP_SYS_HYPERV_CPUID is supported and KVM_CAP_SYS_HYPERV_CPUID implies KVM_CAP_HYPERV_CPUID so get_supported_hv_cpuid_legacy() is never really called. Add asserts to strengthen the protection against broken KVM behavior. Coverity: CID 1458243 Signed-off-by: Vitaly Kuznetsov --- target/i386/kvm/kvm.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/target/i386/kvm/kvm.c b/target/i386/kvm/kvm.c index 59ed8327ac13..e69abe48e3f8 100644 --- a/target/i386/kvm/kvm.c +++ b/target/i386/kvm/kvm.c @@ -974,6 +974,12 @@ static struct kvm_cpuid2 *get_supported_hv_cpuid(CPUState *cs) do_sys_ioctl = kvm_check_extension(kvm_state, KVM_CAP_SYS_HYPERV_CPUID) > 0; + /* + * Non-empty KVM context is needed when KVM_CAP_SYS_HYPERV_CPUID is + * unsupported, kvm_hyperv_expand_features() checks for that. + */ + assert(do_sys_ioctl || cs->kvm_state); + /* * When the buffer is too small, KVM_GET_SUPPORTED_HV_CPUID fails with * -E2BIG, however, it doesn't report back the right size. Keep increasing @@ -1105,6 +1111,14 @@ static uint32_t hv_cpuid_get_host(CPUState *cs, uint32_t func, int reg) if (kvm_check_extension(kvm_state, KVM_CAP_HYPERV_CPUID) > 0) { cpuid = get_supported_hv_cpuid(cs); } else { + /* + * 'cs->kvm_state' may be NULL when Hyper-V features are expanded + * before KVM context is created but this is only done when + * KVM_CAP_SYS_HYPERV_CPUID is supported and it implies + * KVM_CAP_HYPERV_CPUID. + */ + assert(cs->kvm_state); + cpuid = get_supported_hv_cpuid_legacy(cs); } hv_cpuid_cache = cpuid;