Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752503AbbGAESb (ORCPT ); Wed, 1 Jul 2015 00:18:31 -0400 Received: from mga03.intel.com ([134.134.136.65]:18411 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750783AbbGAESW (ORCPT ); Wed, 1 Jul 2015 00:18:22 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.15,383,1432623600"; d="scan'208";a="597893295" Message-ID: <55936976.7090001@intel.com> Date: Wed, 01 Jul 2015 12:15:50 +0800 From: Pan Xinhui User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.5.0 MIME-Version: 1.0 To: "linux-kernel@vger.kernel.org" CC: Yury Norov , Andrew Morton , Rasmus Villemoes , tj@kernel.org, peterz@infradead.org, sudeep.holla@arm.com, mina86@mina86.com, "mnipxh@163.com" , Alexey Klimov , "yanmin_zhang@linux.intel.com" Subject: [PATCH V2] lib/bitmap.c: fix some parsing issues and code style References: <55935B19.5080103@intel.com> In-Reply-To: <55935B19.5080103@intel.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3949 Lines: 135 In __bitmap_parselist we can accept whitespaces on head or tail during every parsing procedure. If input has valid ranges, there is no reason to reject the user. fixes are: 1) if input ends with ',', bit 0 might be set unexpectedly. now we check if any digit is available after every loop. 2) if input has '0-', bit 0 might be set unexpectedly, now we return -EINVAL as this kind of input is definitely wrong. 3) minor code style fix in __bitmap_parse. and avoid in-loop incrementation of ndigits. commit 2528a8b also add some check, but it's still not enough. it only correct the result in fix 1 above. Signed-off-by: Pan Xinhui --- lib/bitmap.c | 43 ++++++++++++++++++++++++++----------------- 1 file changed, 26 insertions(+), 17 deletions(-) --- change log V2 from v1: solve the codes conflicts --- diff --git a/lib/bitmap.c b/lib/bitmap.c index a578a01..b0e3afc 100644 --- a/lib/bitmap.c +++ b/lib/bitmap.c @@ -367,7 +367,8 @@ int __bitmap_parse(const char *buf, unsigned int buflen, nchunks = nbits = totaldigits = c = 0; do { - chunk = ndigits = 0; + chunk = 0; + ndigits = totaldigits; /* Get the next chunk of the bitmap */ while (buflen) { @@ -406,9 +407,9 @@ int __bitmap_parse(const char *buf, unsigned int buflen, return -EOVERFLOW; chunk = (chunk << 4) | hex_to_bin(c); - ndigits++; totaldigits++; + totaldigits++; } - if (ndigits == 0) + if (unlikely(ndigits == totaldigits)) return -EINVAL; if (nchunks == 0 && chunk == 0) continue; @@ -505,7 +506,7 @@ static int __bitmap_parselist(const char *buf, unsigned int buflen, int nmaskbits) { unsigned a, b; - int c, old_c, totaldigits; + int c, old_c, totaldigits, ndigits; const char __user __force *ubuf = (const char __user __force *)buf; int at_start, in_range; @@ -515,6 +516,7 @@ static int __bitmap_parselist(const char *buf, unsigned int buflen, at_start = 1; in_range = 0; a = b = 0; + ndigits = totaldigits; /* Get the next cpu# or a range of cpu#'s */ while (buflen) { @@ -528,23 +530,27 @@ static int __bitmap_parselist(const char *buf, unsigned int buflen, if (isspace(c)) continue; - /* - * If the last character was a space and the current - * character isn't '\0', we've got embedded whitespace. - * This is a no-no, so throw an error. - */ - if (totaldigits && c && isspace(old_c)) - return -EINVAL; - /* A '\0' or a ',' signal the end of a cpu# or range */ if (c == '\0' || c == ',') break; + /* + * whitespaces between digits are not allowed, + * but it's ok if whitespaces are on head or tail. + * when old_c is whilespace, + * if totaldigits == ndigits, whitespace is on head. + * if whitespace is on tail, it should not run here. + * as c was ',' or '\0', + * the last code line has broken the current loop. + */ + if ((totaldigits != ndigits) && isspace(old_c)) + return -EINVAL; if (c == '-') { if (at_start || in_range) return -EINVAL; b = 0; in_range = 1; + at_start = 1; continue; } @@ -557,15 +563,18 @@ static int __bitmap_parselist(const char *buf, unsigned int buflen, at_start = 0; totaldigits++; } + if (unlikely(ndigits == totaldigits)) + continue; + /* if no digit is after '-', it's wrong*/ + if (unlikely(at_start && in_range)) + return -EINVAL; if (!(a <= b)) return -EINVAL; if (b >= nmaskbits) return -ERANGE; - if (!at_start) { - while (a <= b) { - set_bit(a, maskp); - a++; - } + while (a <= b) { + set_bit(a, maskp); + a++; } } while (buflen && c == ','); return 0; -- 1.9.1 -- 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/