From patchwork Wed Feb 4 22:38:15 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sasha Levin X-Patchwork-Id: 436505 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 0D4EE140129 for ; Thu, 5 Feb 2015 09:39:00 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965186AbbBDWin (ORCPT ); Wed, 4 Feb 2015 17:38:43 -0500 Received: from aserp1040.oracle.com ([141.146.126.69]:41782 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S964917AbbBDWim (ORCPT ); Wed, 4 Feb 2015 17:38:42 -0500 Received: from acsinet21.oracle.com (acsinet21.oracle.com [141.146.126.237]) by aserp1040.oracle.com (Sentrion-MTA-4.3.2/Sentrion-MTA-4.3.2) with ESMTP id t14McZrZ018697 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Wed, 4 Feb 2015 22:38:36 GMT Received: from userz7021.oracle.com (userz7021.oracle.com [156.151.31.85]) by acsinet21.oracle.com (8.14.4+Sun/8.14.4) with ESMTP id t14McYHB009224 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=FAIL); Wed, 4 Feb 2015 22:38:35 GMT Received: from ubhmt108.oracle.com (ubhmt108.oracle.com [156.151.24.13]) by userz7021.oracle.com (8.14.4+Sun/8.14.4) with ESMTP id t14McY6C007673; Wed, 4 Feb 2015 22:38:34 GMT Received: from lappy.hsd1.nh.comcast.net (/10.154.128.80) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Wed, 04 Feb 2015 14:38:33 -0800 From: Sasha Levin To: linux-kernel@vger.kernel.org Cc: Sasha Levin , , Alex Williamson , Bjorn Helgaas , Konrad Rzeszutek Wilk , Alexander Graf , Greg Kroah-Hartman , linux-pci@vger.kernel.org (open list:PCI SUBSYSTEM) Subject: [PATCH v3] PCI/sysfs: off by two when checking the limit on driver_override length Date: Wed, 4 Feb 2015 17:38:15 -0500 Message-Id: <1423089495-5647-1-git-send-email-sasha.levin@oracle.com> X-Mailer: git-send-email 2.1.0 X-Source-IP: acsinet21.oracle.com [141.146.126.237] Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org When printing the driver_override parameter when it is 4095 and 4094 bytes long the printing code would access invalid memory because we need count+1 bytes for printing. Cc: # v3.16+ Fixes: 782a985d ("PCI: Introduce new device binding path using pci_dev.driver_override") Cc: Alex Williamson Cc: Bjorn Helgaas Cc: Konrad Rzeszutek Wilk Cc: Alexander Graf Cc: Greg Kroah-Hartman Signed-off-by: Sasha Levin Acked-by: Alex Williamson --- drivers/pci/pci-sysfs.c | 5 +++-- 1 files changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c index aa012fb..312f23a 100644 --- a/drivers/pci/pci-sysfs.c +++ b/drivers/pci/pci-sysfs.c @@ -521,7 +521,8 @@ static ssize_t driver_override_store(struct device *dev, struct pci_dev *pdev = to_pci_dev(dev); char *driver_override, *old = pdev->driver_override, *cp; - if (count > PATH_MAX) + /* We need to keep extra room for a newline */ + if (count >= (PAGE_SIZE - 1)) return -EINVAL; driver_override = kstrndup(buf, count, GFP_KERNEL); @@ -549,7 +550,7 @@ static ssize_t driver_override_show(struct device *dev, { struct pci_dev *pdev = to_pci_dev(dev); - return sprintf(buf, "%s\n", pdev->driver_override); + return snprintf(buf, PAGE_SIZE, "%s\n", pdev->driver_override); } static DEVICE_ATTR_RW(driver_override);