From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934450AbbLQWB1 (ORCPT ); Thu, 17 Dec 2015 17:01:27 -0500 Received: from mga01.intel.com ([192.55.52.88]:40629 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934354AbbLQWBX (ORCPT ); Thu, 17 Dec 2015 17:01:23 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.20,443,1444719600"; d="scan'208";a="619800400" Subject: [PATCH 5/5] x86: simplify early command line parsing To: linux-kernel@vger.kernel.org Cc: Dave Hansen , dave.hansen@linux.intel.com, bp@suse.de, hpa@zytor.com, fenghua.yu@intel.com, yu-cheng.yu@intel.com From: Dave Hansen Date: Thu, 17 Dec 2015 14:01:01 -0800 References: <20151217220051.E8C7A8C9@viggo.jf.intel.com> In-Reply-To: <20151217220051.E8C7A8C9@viggo.jf.intel.com> Message-Id: <20151217220101.F736D3E3@viggo.jf.intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Dave Hansen __cmdline_find_option_bool() tries to account for both NULL-terminated and non-NULL-terminated strings. It keeps 'pos' to look for the end of the buffer and also looks for '!c' in a bunch of places to look for NULL termination. But, it also calls strlen(). You can't call strlen on a non-NULL-terminated string. If !strlen(cmdline), then cmdline[0]=='\0'. In that case, we will go in to the while() loop, set c='\0', hit st_wordstart, notice !c, and will immediately return 0. So, remove the strlen(). It is unnecessary and unsafe. Signed-off-by: Dave Hansen Cc: Borislav Petkov Cc: H. Peter Anvin Cc: linux-kernel@vger.kernel.org Cc: fenghua.yu@intel.com Cc: yu-cheng.yu@intel.com --- b/arch/x86/lib/cmdline.c | 3 --- 1 file changed, 3 deletions(-) diff -puN arch/x86/lib/cmdline.c~x86-early-command-line-non-term arch/x86/lib/cmdline.c --- a/arch/x86/lib/cmdline.c~x86-early-command-line-non-term 2015-12-17 13:54:54.211004070 -0800 +++ b/arch/x86/lib/cmdline.c 2015-12-17 13:54:54.214004206 -0800 @@ -41,9 +41,6 @@ static int __cmdline_find_option_bool(co if (!cmdline) return -1; /* No command line */ - if (!strlen(cmdline)) - return 0; - /* * This 'pos' check ensures we do not overrun * a non-NULL-terminated 'cmdline' _