From patchwork Thu Oct 10 19:15:04 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alex Williamson X-Patchwork-Id: 1174771 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=nongnu.org (client-ip=209.51.188.17; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=) Authentication-Results: ozlabs.org; dmarc=fail (p=none dis=none) header.from=redhat.com 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 ozlabs.org (Postfix) with ESMTPS id 46q15Y2g01z9sDB for ; Fri, 11 Oct 2019 06:16:01 +1100 (AEDT) Received: from localhost ([::1]:43386 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iIdup-00017Y-3z for incoming@patchwork.ozlabs.org; Thu, 10 Oct 2019 15:15:59 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:34095) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iIdu3-00015z-Ln for qemu-devel@nongnu.org; Thu, 10 Oct 2019 15:15:12 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iIdu2-00019g-G5 for qemu-devel@nongnu.org; Thu, 10 Oct 2019 15:15:11 -0400 Received: from mx1.redhat.com ([209.132.183.28]:60116) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1iIdu2-00019W-Ab for qemu-devel@nongnu.org; Thu, 10 Oct 2019 15:15:10 -0400 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 8154430013A1 for ; Thu, 10 Oct 2019 19:15:09 +0000 (UTC) Received: from gimli.home (ovpn-118-102.phx2.redhat.com [10.3.118.102]) by smtp.corp.redhat.com (Postfix) with ESMTP id 46478100EBD6; Thu, 10 Oct 2019 19:15:05 +0000 (UTC) Subject: [PULL 1/1] hw/vfio/pci: fix double free in vfio_msi_disable From: Alex Williamson To: qemu-devel@nongnu.org Date: Thu, 10 Oct 2019 13:15:04 -0600 Message-ID: <157073488735.23153.15612488542845648378.stgit@gimli.home> In-Reply-To: <157073476983.23153.13333563650903948665.stgit@gimli.home> References: <157073476983.23153.13333563650903948665.stgit@gimli.home> User-Agent: StGit/0.19-dirty MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.42]); Thu, 10 Oct 2019 19:15:09 +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: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" From: Evgeny Yakovlev 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 Signed-off-by: Alex Williamson --- hw/vfio/pci.c | 1 + 1 file changed, 1 insertion(+) diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c index c5e6fe61cb3e..12fac3980465 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;