From patchwork Wed Jul 14 12:27:53 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yi Zhuang X-Patchwork-Id: 1505162 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=lists.ozlabs.org (client-ip=112.213.38.117; helo=lists.ozlabs.org; envelope-from=linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org; receiver=) Received: from lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 4GPxjX0lkNz9sj1 for ; Wed, 14 Jul 2021 22:32:48 +1000 (AEST) Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4GPxjX00l0z30Dv for ; Wed, 14 Jul 2021 22:32:48 +1000 (AEST) X-Original-To: linuxppc-dev@lists.ozlabs.org Delivered-To: linuxppc-dev@lists.ozlabs.org Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=huawei.com (client-ip=45.249.212.188; helo=szxga02-in.huawei.com; envelope-from=zhuangyi1@huawei.com; receiver=) Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4GPxj84zkzz2yZ6 for ; Wed, 14 Jul 2021 22:32:25 +1000 (AEST) 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: , 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 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 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: hegdevasant@linux.vnet.ibm.com, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, zhuangyi1@huawei.com Errors-To: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" 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); }