From patchwork Thu Oct 20 09:30:55 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Maxim Levitsky X-Patchwork-Id: 13012911 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2FA5BC433FE for ; Thu, 20 Oct 2022 09:31:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230410AbiJTJbk (ORCPT ); Thu, 20 Oct 2022 05:31:40 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56940 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230390AbiJTJb2 (ORCPT ); Thu, 20 Oct 2022 05:31:28 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A415C1578B7 for ; Thu, 20 Oct 2022 02:31:24 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1666258283; 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=nm86sopHALiAvOTB3Mb1uaCRxtNMK3Osw7jYg3LC+M0=; b=PrBzeCYAoQuMxz23urWDMNkIm5te+d7ccZd/Ny3fT2+GBPnEdZQzALrJUB0+ZWxImEOq0R FxlTuhZwN9aiV2wCuoOqdZKlnGjeOvZ3/+qd0nm8GSV8P1te/gh8W9+vapaOfVD/6YmAEk iJ9eu6619IYI28GShB35+XZwssdMIUc= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-423-MgE-q4rgP1SE4fwskpXN-A-1; Thu, 20 Oct 2022 05:31:18 -0400 X-MC-Unique: MgE-q4rgP1SE4fwskpXN-A-1 Received: from smtp.corp.redhat.com (int-mx09.intmail.prod.int.rdu2.redhat.com [10.11.54.9]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 9305729324B0; Thu, 20 Oct 2022 09:31:17 +0000 (UTC) Received: from localhost.localdomain (ovpn-192-51.brq.redhat.com [10.40.192.51]) by smtp.corp.redhat.com (Postfix) with ESMTP id C4AAC49BB60; Thu, 20 Oct 2022 09:31:14 +0000 (UTC) From: Maxim Levitsky To: kvm@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Paolo Bonzini , Borislav Petkov , Ingo Molnar , Sean Christopherson , x86@kernel.org, Thomas Gleixner , Dave Hansen , "H. Peter Anvin" , Maxim Levitsky , stable@vger.kernel.org Subject: [PATCH 4/4] KVM: x86: forcibly leave nested mode on vCPU reset Date: Thu, 20 Oct 2022 12:30:55 +0300 Message-Id: <20221020093055.224317-5-mlevitsk@redhat.com> In-Reply-To: <20221020093055.224317-1-mlevitsk@redhat.com> References: <20221020093055.224317-1-mlevitsk@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.9 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org While not obivous, kvm_vcpu_reset leaves the nested mode by clearing 'vcpu->arch.hflags' but it does so without all the required housekeeping. This makes SVM and VMX continue to use vmcs02/vmcb02 while the cpu is not in nested mode. In particular, in SVM code, it makes the 'svm_free_nested' free the vmcb02, while still in use, which later triggers use after free and a kernel crash. This issue is assigned CVE-2022-3344 Cc: stable@vger.kernel.org Signed-off-by: Maxim Levitsky --- arch/x86/kvm/x86.c | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index d86a8aae1471d3..313c4a6dc65e45 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -11931,6 +11931,7 @@ void kvm_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event) WARN_ON_ONCE(!init_event && (old_cr0 || kvm_read_cr3(vcpu) || kvm_read_cr4(vcpu))); + kvm_leave_nested(vcpu); kvm_lapic_reset(vcpu, init_event); vcpu->arch.hflags = 0;