Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S966537AbbBDXJV (ORCPT ); Wed, 4 Feb 2015 18:09:21 -0500 Received: from mx1.redhat.com ([209.132.183.28]:54598 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756042AbbBDXJT (ORCPT ); Wed, 4 Feb 2015 18:09:19 -0500 Message-ID: <1423091348.22865.477.camel@redhat.com> Subject: Re: [PATCH v3] PCI/sysfs: off by two when checking the limit on driver_override length From: Alex Williamson To: Sasha Levin Cc: linux-kernel@vger.kernel.org, stable@vger.kernel.org, Bjorn Helgaas , Konrad Rzeszutek Wilk , Alexander Graf , Greg Kroah-Hartman , "open list:PCI SUBSYSTEM" Date: Wed, 04 Feb 2015 16:09:08 -0700 In-Reply-To: <1423089495-5647-1-git-send-email-sasha.levin@oracle.com> References: <1423089495-5647-1-git-send-email-sasha.levin@oracle.com> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1909 Lines: 52 On Wed, 2015-02-04 at 17:38 -0500, Sasha Levin wrote: > 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 > --- > drivers/pci/pci-sysfs.c | 5 +++-- > 1 files changed, 3 insertions(+), 2 deletions(-) Acked-by: Alex Williamson > 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); > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/