From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754689Ab0LHBK1 (ORCPT ); Tue, 7 Dec 2010 20:10:27 -0500 Received: from kroah.org ([198.145.64.141]:33826 "EHLO coco.kroah.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932838Ab0LHBDv (ORCPT ); Tue, 7 Dec 2010 20:03:51 -0500 X-Mailbox-Line: From gregkh@clark.site Tue Dec 7 16:57:47 2010 Message-Id: <20101208005747.312069308@clark.site> User-Agent: quilt/0.48-11.2 Date: Tue, 07 Dec 2010 17:00:36 -0800 From: Greg KH To: linux-kernel@vger.kernel.org, stable@kernel.org Cc: stable-review@kernel.org, torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Thadeu Lima de Souza Cascardo , Matthew Garrett Subject: [259/289] wmi: use memcmp instead of strncmp to compare GUIDs In-Reply-To: <20101208005821.GA2922@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 2.6.36-stable review patch. If anyone has any objections, please let us know. ------------------ From: Thadeu Lima de Souza Cascardo commit 8b14d7b22c61f17ccb869e0047d9df6dd9f50a9f upstream. While looking for the duplicates in /sys/class/wmi/, I couldn't find them. The code that looks for duplicates uses strncmp in a binary GUID, which may contain zero bytes. The right function is memcmp, which is also used in another section of wmi code. It was finding 49142400-C6A3-40FA-BADB-8A2652834100 as a duplicate of 39142400-C6A3-40FA-BADB-8A2652834100. Since the first byte is the fourth printed, they were found as equal by strncmp. Signed-off-by: Thadeu Lima de Souza Cascardo Signed-off-by: Matthew Garrett Signed-off-by: Greg Kroah-Hartman --- drivers/platform/x86/wmi.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/drivers/platform/x86/wmi.c +++ b/drivers/platform/x86/wmi.c @@ -801,7 +801,7 @@ static bool guid_already_parsed(const ch wblock = list_entry(p, struct wmi_block, list); gblock = &wblock->gblock; - if (strncmp(gblock->guid, guid_string, 16) == 0) + if (memcmp(gblock->guid, guid_string, 16) == 0) return true; } return false;