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 76E5BC433EF for ; Fri, 14 Jan 2022 08:23:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237647AbiANIXR (ORCPT ); Fri, 14 Jan 2022 03:23:17 -0500 Received: from smtp23.cstnet.cn ([159.226.251.23]:48726 "EHLO cstnet.cn" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S237202AbiANIVm (ORCPT ); Fri, 14 Jan 2022 03:21:42 -0500 Received: from localhost.localdomain (unknown [124.16.138.126]) by APP-03 (Coremail) with SMTP id rQCowAD3_S2AMuFh4HuGBQ--.10268S2; Fri, 14 Jan 2022 16:21:20 +0800 (CST) From: Jiasheng Jiang To: keescook@chromium.org, arnd@arndb.de, gregkh@linuxfoundation.org Cc: linux-kernel@vger.kernel.org, Jiasheng Jiang Subject: [PATCH] lkdtm/bugs: Check for the NULL pointer after calling kmalloc Date: Fri, 14 Jan 2022 16:21:19 +0800 Message-Id: <20220114082119.1270966-1-jiasheng@iscas.ac.cn> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CM-TRANSID: rQCowAD3_S2AMuFh4HuGBQ--.10268S2 X-Coremail-Antispam: 1UD129KBjvdXoW7Wr4UGw4UJFyxAr4xtw4xJFb_yoWDCrc_Ga n5Jr98JryYkF1Skwn7tr97urZFka1DuF4FqF9xt3y3A34xZr12vFyqgrn3Xw43GayvqFsx CrWDZay0vr129jkaLaAFLSUrUUUUUb8apTn2vfkv8UJUUUU8Yxn0WfASr-VFAUDa7-sFnT 9fnUUIcSsGvfJTRUUUbckFF20E14v26r1j6r4UM7CY07I20VC2zVCF04k26cxKx2IYs7xG 6rWj6s0DM7CIcVAFz4kK6r1j6r18M28lY4IEw2IIxxk0rwA2F7IY1VAKz4vEj48ve4kI8w A2z4x0Y4vE2Ix0cI8IcVAFwI0_Xr0_Ar1l84ACjcxK6xIIjxv20xvEc7CjxVAFwI0_Cr0_ Gr1UM28EF7xvwVC2z280aVAFwI0_Cr1j6rxdM28EF7xvwVC2z280aVCY1x0267AKxVW0oV Cq3wAS0I0E0xvYzxvE52x082IY62kv0487Mc02F40EFcxC0VAKzVAqx4xG6I80ewAv7VC0 I7IYx2IY67AKxVWUJVWUGwAv7VC2z280aVAFwI0_Jr0_Gr1lOx8S6xCaFVCjc4AY6r1j6r 4UM4x0Y48IcxkI7VAKI48JM4x0x7Aq67IIx4CEVc8vx2IErcIFxwCY02Avz4vE14v_GFyl 42xK82IYc2Ij64vIr41l4I8I3I0E4IkC6x0Yz7v_Jr0_Gr1lx2IqxVAqx4xG67AKxVWUJV WUGwC20s026x8GjcxK67AKxVWUGVWUWwC2zVAF1VAY17CE14v26r126r1DMIIYrxkI7VAK I48JMIIF0xvE2Ix0cI8IcVAFwI0_Jr0_JF4lIxAIcVC0I7IYx2IY6xkF7I0E14v26r1j6r 4UMIIF0xvE42xK8VAvwI8IcIk0rVWrZr1j6s0DMIIF0xvEx4A2jsIE14v26r1j6r4UMIIF 0xvEx4A2jsIEc7CjxVAFwI0_Gr0_Gr1UYxBIdaVFxhVjvjDU0xZFpf9x0JUIzuXUUUUU= X-Originating-IP: [124.16.138.126] X-CM-SenderInfo: pmld2xxhqjqxpvfd2hldfou0/ Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org As the possible failure of the kmalloc(), the not_checked and checked could be NULL pointer. Therefore, it should be better to check it in order to avoid the dereference of the NULL pointer. And since it is just a test, it may directly return without error number. Fixes: ae2e1aad3e48 ("drivers/misc/lkdtm/bugs.c: add arithmetic overflow and array bounds checks") Signed-off-by: Jiasheng Jiang --- drivers/misc/lkdtm/bugs.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/misc/lkdtm/bugs.c b/drivers/misc/lkdtm/bugs.c index f4cb94a9aa9c..12c474a38494 100644 --- a/drivers/misc/lkdtm/bugs.c +++ b/drivers/misc/lkdtm/bugs.c @@ -325,6 +325,8 @@ void lkdtm_ARRAY_BOUNDS(void) not_checked = kmalloc(sizeof(*not_checked) * 2, GFP_KERNEL); checked = kmalloc(sizeof(*checked) * 2, GFP_KERNEL); + if (!not_checked || !checked) + return; pr_info("Array access within bounds ...\n"); /* For both, touch all bytes in the actual member size. */ -- 2.25.1