From nobody Tue Feb 10 03:05:19 2026 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of redhat.com designates 209.132.183.28 as permitted sender) client-ip=209.132.183.28; envelope-from=libvir-list-bounces@redhat.com; helo=mx1.redhat.com; Authentication-Results: mx.zoho.com; spf=pass (zoho.com: domain of redhat.com designates 209.132.183.28 as permitted sender) smtp.mailfrom=libvir-list-bounces@redhat.com; Return-Path: Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) by mx.zohomail.com with SMTPS id 149639866252248.65650584771515; Fri, 2 Jun 2017 03:17:42 -0700 (PDT) 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 mx1.redhat.com (Postfix) with ESMTPS id 6BE58142A65; Fri, 2 Jun 2017 10:17:39 +0000 (UTC) Received: from colo-mx.corp.redhat.com (colo-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.20]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 368CC83EB7; Fri, 2 Jun 2017 10:17:39 +0000 (UTC) Received: from lists01.pubmisc.prod.ext.phx2.redhat.com (lists01.pubmisc.prod.ext.phx2.redhat.com [10.5.19.33]) by colo-mx.corp.redhat.com (Postfix) with ESMTP id C2EE4180BAFC; Fri, 2 Jun 2017 10:17:38 +0000 (UTC) Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) by lists01.pubmisc.prod.ext.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id v52AHRgT027907 for ; Fri, 2 Jun 2017 06:17:27 -0400 Received: by smtp.corp.redhat.com (Postfix) id ABE5D18216; Fri, 2 Jun 2017 10:17:27 +0000 (UTC) Received: from localhost.localdomain.com (ovpn-116-108.phx2.redhat.com [10.3.116.108]) by smtp.corp.redhat.com (Postfix) with ESMTP id 680665C54A for ; Fri, 2 Jun 2017 10:17:27 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 6BE58142A65 Authentication-Results: ext-mx10.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx10.extmail.prod.ext.phx2.redhat.com; spf=pass smtp.mailfrom=libvir-list-bounces@redhat.com DKIM-Filter: OpenDKIM Filter v2.11.0 mx1.redhat.com 6BE58142A65 From: John Ferlan To: libvir-list@redhat.com Date: Fri, 2 Jun 2017 06:17:18 -0400 Message-Id: <20170602101722.12157-5-jferlan@redhat.com> In-Reply-To: <20170602101722.12157-1-jferlan@redhat.com> References: <20170602101722.12157-1-jferlan@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-loop: libvir-list@redhat.com Subject: [libvirt] [PATCH v2 4/8] util: Add safety net of checks to ensure valid object X-BeenThere: libvir-list@redhat.com X-Mailman-Version: 2.1.12 Precedence: junk List-Id: Development discussions about the libvirt library & tools List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Sender: libvir-list-bounces@redhat.com Errors-To: libvir-list-bounces@redhat.com X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.39]); Fri, 02 Jun 2017 10:17:40 +0000 (UTC) X-ZohoMail: RSF_0 Z_629925259 SPT_0 Content-Type: text/plain; charset="utf-8" The virObject logic "assumes" that whatever is passed to its API's would be some sort of virObjectPtr; however, if it is not then some really bad things can happen. So far there's been only virObject{Ref|Unref}, virObject{Lock|Unlock}, and virObjectIsClass and the virObject and virObjectLockable class consumers have been well behaved and code well tested. Soon there will be more consumers and one such consumer tripped over this during testing by passing a virHashTablePtr to virObjectIsClass which ends up calling virClassIsDerivedFrom using "obj->klass", which wasn't really a klass object causing one of those bad things to happen. To avoid the future possibility that a non virObject class memory was passed to some virObject* API, this patch adds two new checks - one to validate that the object has the 0xCAFExxxx value in obj->->u.s.magic and the other to ensure obj->u.s.magic doesn't "wrap" some day to 0xCAFF0000 if we ever get that many objects. It is still left up to the caller to handle the failed API calls just as it would be if it passed a NULL opaque pointer anyobj. Signed-off-by: John Ferlan --- src/util/virobject.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/src/util/virobject.c b/src/util/virobject.c index 9f5f187..e0465b1 100644 --- a/src/util/virobject.c +++ b/src/util/virobject.c @@ -22,6 +22,7 @@ #include =20 #define VIR_PARENT_REQUIRED /* empty, to allow virObject to have no parent= */ +#include #include "virobject.h" #include "virthread.h" #include "viralloc.h" @@ -47,10 +48,12 @@ struct _virClass { virObjectDisposeCallback dispose; }; =20 +#define VIR_OBJECT_NOTVALID(obj) (!obj || ((obj->u.s.magic & 0xCAFE0000) != =3D 0xCAFE0000)) + #define VIR_OBJECT_USAGE_PRINT_WARNING(anyobj, objclass) = \ do { = \ virObjectPtr obj =3D anyobj; = \ - if (!obj) = \ + if (VIR_OBJECT_NOTVALID(obj)) = \ VIR_WARN("Object %p is not a virObject class instance", anyobj= );\ else = \ VIR_WARN("Object %p (%s) is not a %s instance", = \ @@ -156,6 +159,7 @@ virClassNew(virClassPtr parent, if (VIR_STRDUP(klass->name, name) < 0) goto error; klass->magic =3D virAtomicIntInc(&magicCounter); + assert(klass->magic <=3D 0xCAFEFFFF); klass->objectSize =3D objectSize; klass->dispose =3D dispose; =20 @@ -272,7 +276,7 @@ virObjectUnref(void *anyobj) { virObjectPtr obj =3D anyobj; =20 - if (!obj) + if (VIR_OBJECT_NOTVALID(obj)) return false; =20 bool lastRef =3D virAtomicIntDecAndTest(&obj->u.s.refs); @@ -311,7 +315,7 @@ virObjectRef(void *anyobj) { virObjectPtr obj =3D anyobj; =20 - if (!obj) + if (VIR_OBJECT_NOTVALID(obj)) return NULL; virAtomicIntInc(&obj->u.s.refs); PROBE(OBJECT_REF, "obj=3D%p", obj); @@ -389,7 +393,7 @@ virObjectIsClass(void *anyobj, virClassPtr klass) { virObjectPtr obj =3D anyobj; - if (!obj) + if (VIR_OBJECT_NOTVALID(obj)) return false; =20 return virClassIsDerivedFrom(obj->klass, klass); --=20 2.9.4 -- libvir-list mailing list libvir-list@redhat.com https://www.redhat.com/mailman/listinfo/libvir-list