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 X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 58B96C07E9A for ; Wed, 14 Jul 2021 12:14:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2D576613B6 for ; Wed, 14 Jul 2021 12:14:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239378AbhGNMQ4 (ORCPT ); Wed, 14 Jul 2021 08:16:56 -0400 Received: from szxga02-in.huawei.com ([45.249.212.188]:6927 "EHLO szxga02-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239209AbhGNMQy (ORCPT ); Wed, 14 Jul 2021 08:16:54 -0400 Received: from dggeml757-chm.china.huawei.com (unknown [172.30.72.55]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4GPxCk6Cwzz7BR9; Wed, 14 Jul 2021 20:10:26 +0800 (CST) Received: from huawei.com (10.90.53.225) by dggeml757-chm.china.huawei.com (10.1.199.137) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2176.2; Wed, 14 Jul 2021 20:13:59 +0800 From: Yi Zhuang To: , CC: , , , , Subject: [PATCH v2] powerpc/rtas_flash: fix a potential buffer overflow Date: Wed, 14 Jul 2021 20:27:53 +0800 Message-ID: <20210714122753.76021-1-zhuangyi1@huawei.com> X-Mailer: git-send-email 2.26.0.106.g9fadedd MIME-Version: 1.0 Content-Transfer-Encoding: 7BIT Content-Type: text/plain; charset=US-ASCII X-Originating-IP: [10.90.53.225] X-ClientProxiedBy: dggems703-chm.china.huawei.com (10.3.19.180) To dggeml757-chm.china.huawei.com (10.1.199.137) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Since snprintf() returns the possible output size instead of the actual output size, the available flash_msg length returned by get_validate_flash_msg may exceed the given buffer limit when simple_read_from_buffer calls copy_to_user Reported-by: kernel test robot Fixes: a94a14720eaf5 powerpc/rtas_flash: Fix validate_flash buffer overflow issue Signed-off-by: Yi Zhuang --- arch/powerpc/kernel/rtas_flash.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/arch/powerpc/kernel/rtas_flash.c b/arch/powerpc/kernel/rtas_flash.c index a99179d83538..062f0724c2ff 100644 --- a/arch/powerpc/kernel/rtas_flash.c +++ b/arch/powerpc/kernel/rtas_flash.c @@ -470,9 +470,14 @@ static int get_validate_flash_msg(struct rtas_validate_flash_t *args_buf, if (args_buf->status >= VALIDATE_TMP_UPDATE) { n = sprintf(msg, "%d\n", args_buf->update_results); if ((args_buf->update_results >= VALIDATE_CUR_UNKNOWN) || - (args_buf->update_results == VALIDATE_TMP_UPDATE)) + (args_buf->update_results == VALIDATE_TMP_UPDATE)) { n += snprintf(msg + n, msglen - n, "%s\n", args_buf->buf); + if (n >= msglen) { + n = msglen; + printk(KERN_ERR "FLASH: msg too long.\n"); + } + } } else { n = sprintf(msg, "%d\n", args_buf->status); } -- 2.26.0.106.g9fadedd