From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8C8C4EB64D9 for ; Wed, 14 Jun 2023 11:32:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238399AbjFNLcr (ORCPT ); Wed, 14 Jun 2023 07:32:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48146 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234041AbjFNLco (ORCPT ); Wed, 14 Jun 2023 07:32:44 -0400 Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 281F810CB for ; Wed, 14 Jun 2023 04:32:43 -0700 (PDT) Received: from kwepemi500009.china.huawei.com (unknown [172.30.72.54]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4Qh37K3YrRzqTRl; Wed, 14 Jun 2023 19:27:41 +0800 (CST) Received: from [10.67.110.89] (10.67.110.89) by kwepemi500009.china.huawei.com (7.221.188.199) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.23; Wed, 14 Jun 2023 19:32:38 +0800 Message-ID: <86c6040d-17ab-fb01-2b75-717d82ba9345@huawei.com> Date: Wed, 14 Jun 2023 19:32:38 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.4.1 Subject: Re: [PATCH v7] kobject: Fix global-out-of-bounds in kobject_action_type() To: , CC: References: <20230518091614.137522-1-xiafukun@huawei.com> From: Xia Fukun In-Reply-To: <20230518091614.137522-1-xiafukun@huawei.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.67.110.89] X-ClientProxiedBy: dggems703-chm.china.huawei.com (10.3.19.180) To kwepemi500009.china.huawei.com (7.221.188.199) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2023/5/18 17:16, Xia Fukun wrote: > --- > v6 -> v7: > - Move macro UEVENT_KACT_STRSIZE to the .c file to > improve maintainability. > Gentle ping ... UEVENT_KACT_STRSIZE is defined as the maximum length of the string contained in kobject_actions[]. At present, the maximum length of strings in this array is 7. Based on the actual meaning of these strings, these actions will not exceed 16 if there are any subsequent changes. I have submitted v7 of the patch according to your suggestion and tested it to ensure its functionality is correct. Please take the time to review it. Thank you very much. > --- > lib/kobject_uevent.c | 38 +++++++++++++++++++++++++------------- > 1 file changed, 25 insertions(+), 13 deletions(-) > > diff --git a/lib/kobject_uevent.c b/lib/kobject_uevent.c > index 7c44b7ae4c5c..2171e1648dad 100644 > --- a/lib/kobject_uevent.c > +++ b/lib/kobject_uevent.c > @@ -47,6 +47,14 @@ static LIST_HEAD(uevent_sock_list); > /* This lock protects uevent_seqnum and uevent_sock_list */ > static DEFINE_MUTEX(uevent_sock_mutex); > > +/* > + * The maximum length of the string contained in kobject_actions[]. > + * If there are any actions added or modified, please ensure that > + * the string length does not exceed the macro, otherwise > + * should modify the macro definition. > + */ > +#define UEVENT_KACT_STRSIZE 16 > + > /* the strings here must match the enum in include/linux/kobject.h */ > static const char *kobject_actions[] = { > [KOBJ_ADD] = "add", > @@ -66,7 +74,8 @@ static int kobject_action_type(const char *buf, size_t count, > enum kobject_action action; > size_t count_first; > const char *args_start; > - int ret = -EINVAL; > + int i, ret = -EINVAL; > + char kobj_act_buf[UEVENT_KACT_STRSIZE] = {0}; > > if (count && (buf[count-1] == '\n' || buf[count-1] == '\0')) > count--; > @@ -77,21 +86,24 @@ static int kobject_action_type(const char *buf, size_t count, > args_start = strnchr(buf, count, ' '); > if (args_start) { > count_first = args_start - buf; > + if (count_first > UEVENT_KACT_STRSIZE) > + goto out; > + > args_start = args_start + 1; > + strncpy(kobj_act_buf, buf, count_first); > + i = sysfs_match_string(kobject_actions, kobj_act_buf); > } else > - count_first = count; > + i = sysfs_match_string(kobject_actions, buf); > > - for (action = 0; action < ARRAY_SIZE(kobject_actions); action++) { > - if (strncmp(kobject_actions[action], buf, count_first) != 0) > - continue; > - if (kobject_actions[action][count_first] != '\0') > - continue; > - if (args) > - *args = args_start; > - *type = action; > - ret = 0; > - break; > - } > + if (i < 0) > + goto out; > + > + action = i; > + if (args) > + *args = args_start; > + > + *type = action; > + ret = 0; > out: > return ret; > }