From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from userp1040.oracle.com ([156.151.31.81]:45719 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751520AbbABA1c (ORCPT ); Thu, 1 Jan 2015 19:27:32 -0500 From: Sasha Levin To: linux-kernel@vger.kernel.org Cc: gregkh@linuxfoundation.org, Sasha Levin , Bjorn Helgaas , linux-pci@vger.kernel.org (open list:PCI SUBSYSTEM) Subject: [PATCH] PCI/sysfs: off by two and memory corruption in driver_override parameter Date: Thu, 1 Jan 2015 19:27:12 -0500 Message-Id: <1420158432-645-1-git-send-email-sasha.levin@oracle.com> Sender: linux-pci-owner@vger.kernel.org List-ID: There are two different issues fixed here: - On nun-NULL terminated input a random byte of memory would get flipped from '\n' to '\0'. - When printing the driver_override parameter when it is 4095 and 4094 bytes long the printing code would access invalid memory. Signed-off-by: Sasha Levin --- drivers/pci/pci-sysfs.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c index aa012fb..be6b2b1 100644 --- a/drivers/pci/pci-sysfs.c +++ b/drivers/pci/pci-sysfs.c @@ -521,17 +521,17 @@ 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 >= (PATH_MAX - 1)) return -EINVAL; driver_override = kstrndup(buf, count, GFP_KERNEL); if (!driver_override) return -ENOMEM; - cp = strchr(driver_override, '\n'); - if (cp) - *cp = '\0'; - + driver_override[count] = '\0'; + if (driver_override[count - 1] == '\n') + driver_override[count - 1] = 0; if (strlen(driver_override)) { pdev->driver_override = driver_override; } else { -- 1.7.10.4