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=-6.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED 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 7DEB0C4360C for ; Thu, 26 Sep 2019 17:20:42 +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 5323B222C7 for ; Thu, 26 Sep 2019 17:20:42 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5323B222C7 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]:41504 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iDXRZ-0006dT-5S for qemu-devel@archiver.kernel.org; Thu, 26 Sep 2019 13:20:41 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:54717) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iDXNW-0004Lc-Ch for qemu-devel@nongnu.org; Thu, 26 Sep 2019 13:16:31 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iDXNU-0006jn-Bl for qemu-devel@nongnu.org; Thu, 26 Sep 2019 13:16:30 -0400 Received: from mx1.redhat.com ([209.132.183.28]:54058) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1iDXNU-0006Rc-3m for qemu-devel@nongnu.org; Thu, 26 Sep 2019 13:16:28 -0400 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 mx1.redhat.com (Postfix) with ESMTPS id 9F98D300BEA4; Thu, 26 Sep 2019 17:16:23 +0000 (UTC) Received: from x1.home (ovpn-118-102.phx2.redhat.com [10.3.118.102]) by smtp.corp.redhat.com (Postfix) with ESMTP id 673825D9C9; Thu, 26 Sep 2019 17:16:23 +0000 (UTC) Date: Thu, 26 Sep 2019 11:16:22 -0600 From: Alex Williamson To: Evgeny Yakovlev Subject: Re: [PATCH] hw/vfio/pci: fix double free in vfio_msi_disable Message-ID: <20190926111622.5cd9f856@x1.home> In-Reply-To: <1569497375-24633-1-git-send-email-wrfsh@yandex-team.ru> References: <1569497375-24633-1-git-send-email-wrfsh@yandex-team.ru> Organization: Red Hat MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.42]); Thu, 26 Sep 2019 17:16:23 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 209.132.183.28 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: qemu-devel@nongnu.org, yc-core@yandex-team.ru Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Thu, 26 Sep 2019 14:29:35 +0300 Evgeny Yakovlev wrote: > The following guest behaviour patter leads to double free in VFIO PCI: > > 1. Guest enables MSI interrupts > vfio_msi_enable is called, but fails in vfio_enable_vectors. > In our case this was because VFIO GPU device was in D3 state. > Unhappy path in vfio_msi_enable will g_free(vdev->msi_vectors) but not > set this pointer to NULL > > 2. Guest still sees MSI an enabled after that because emulated config > write is done in vfio_pci_write_config unconditionally before calling > vfio_msi_enable > > 3. Guest disables MSI interrupts > vfio_msi_disable is called and tries to g_free(vdev->msi_vectors) > in vfio_msi_disable_common => double free > > Signed-off-by: Evgeny Yakovlev > --- > hw/vfio/pci.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c > index c5e6fe6..12fac39 100644 > --- a/hw/vfio/pci.c > +++ b/hw/vfio/pci.c > @@ -651,6 +651,7 @@ retry: > } > > g_free(vdev->msi_vectors); > + vdev->msi_vectors = NULL; > > if (ret > 0 && ret != vdev->nr_vectors) { > vdev->nr_vectors = ret; Looks correct to me, I'll queue it. Thanks, Alex