From patchwork Mon Jul 10 07:48:44 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?C=C3=A9dric_Le_Goater?= X-Patchwork-Id: 13306409 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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id ADC76EB64D9 for ; Mon, 10 Jul 2023 07:51:28 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qIleK-0006li-0C; Mon, 10 Jul 2023 03:49:36 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qIldz-0006NW-Ov for qemu-devel@nongnu.org; Mon, 10 Jul 2023 03:49:20 -0400 Received: from gandalf.ozlabs.org ([150.107.74.76]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qIldy-0006us-5p for qemu-devel@nongnu.org; Mon, 10 Jul 2023 03:49:15 -0400 Received: from gandalf.ozlabs.org (gandalf.ozlabs.org [150.107.74.76]) by gandalf.ozlabs.org (Postfix) with ESMTP id 4Qzx3F3ql4z4wxx; Mon, 10 Jul 2023 17:49:13 +1000 (AEST) Received: from authenticated.ozlabs.org (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by mail.ozlabs.org (Postfix) with ESMTPSA id 4Qzx3C2cd2z4wy9; Mon, 10 Jul 2023 17:49:11 +1000 (AEST) From: =?utf-8?q?C=C3=A9dric_Le_Goater?= To: qemu-devel@nongnu.org Cc: Richard Henderson , Alex Williamson , Avihai Horon , =?utf-8?q?Philippe_Mathieu-Daud=C3=A9?= , =?utf-8?q?C?= =?utf-8?q?=C3=A9dric_Le_Goater?= Subject: [PULL 07/11] vfio: Fix null pointer dereference bug in vfio_bars_finalize() Date: Mon, 10 Jul 2023 09:48:44 +0200 Message-ID: <20230710074848.456453-8-clg@redhat.com> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230710074848.456453-1-clg@redhat.com> References: <20230710074848.456453-1-clg@redhat.com> MIME-Version: 1.0 Received-SPF: pass client-ip=150.107.74.76; envelope-from=SRS0=Zxd8=C4=redhat.com=clg@ozlabs.org; helo=gandalf.ozlabs.org X-Spam_score_int: -16 X-Spam_score: -1.7 X-Spam_bar: - X-Spam_report: (-1.7 / 5.0 requ) BAYES_00=-1.9, HEADER_FROM_DIFFERENT_DOMAINS=0.249, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org From: Avihai Horon vfio_realize() has the following flow: 1. vfio_bars_prepare() -- sets VFIOBAR->size. 2. msix_early_setup(). 3. vfio_bars_register() -- allocates VFIOBAR->mr. After vfio_bars_prepare() is called msix_early_setup() can fail. If it does fail, vfio_bars_register() is never called and VFIOBAR->mr is not allocated. In this case, vfio_bars_finalize() is called as part of the error flow to free the bars' resources. However, vfio_bars_finalize() calls object_unparent() for VFIOBAR->mr after checking only VFIOBAR->size, and thus we get a null pointer dereference. Fix it by checking VFIOBAR->mr in vfio_bars_finalize(). Fixes: 89d5202edc50 ("vfio/pci: Allow relocating MSI-X MMIO") Signed-off-by: Avihai Horon Reviewed-by: Philippe Mathieu-Daudé Reviewed-by: Cédric Le Goater Reviewed-by: Alex Williamson Signed-off-by: Cédric Le Goater --- hw/vfio/pci.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c index 68dd99283620..c89fdf7ae6c2 100644 --- a/hw/vfio/pci.c +++ b/hw/vfio/pci.c @@ -1752,9 +1752,11 @@ static void vfio_bars_finalize(VFIOPCIDevice *vdev) vfio_bar_quirk_finalize(vdev, i); vfio_region_finalize(&bar->region); - if (bar->size) { + if (bar->mr) { + assert(bar->size); object_unparent(OBJECT(bar->mr)); g_free(bar->mr); + bar->mr = NULL; } }