From patchwork Tue Nov 15 08:35:55 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Li Hua X-Patchwork-Id: 625429 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 4BF89C4332F for ; Tue, 15 Nov 2022 08:07:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232629AbiKOIHO (ORCPT ); Tue, 15 Nov 2022 03:07:14 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37012 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229585AbiKOIHN (ORCPT ); Tue, 15 Nov 2022 03:07:13 -0500 Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C0C792124E; Tue, 15 Nov 2022 00:07:12 -0800 (PST) Received: from canpemm500009.china.huawei.com (unknown [172.30.72.55]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4NBJg0745mzRpKx; Tue, 15 Nov 2022 16:06:52 +0800 (CST) Received: from huawei.com (10.67.174.191) by canpemm500009.china.huawei.com (7.192.105.203) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Tue, 15 Nov 2022 16:07:06 +0800 From: Li Hua To: , CC: , , , , Subject: [PATCH] watchdog: pcwd_usb: Fix attempting to access uninitialized memory Date: Tue, 15 Nov 2022 16:35:55 +0800 Message-ID: <20221115083555.22928-1-hucool.lihua@huawei.com> X-Mailer: git-send-email 2.17.1 MIME-Version: 1.0 X-Originating-IP: [10.67.174.191] X-ClientProxiedBy: dggems701-chm.china.huawei.com (10.3.19.178) To canpemm500009.china.huawei.com (7.192.105.203) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-watchdog@vger.kernel.org The stack variable msb and lsb may be used uninitialized in function usb_pcwd_get_temperature and usb_pcwd_get_timeleft when usb card no response. The build waring is: drivers/watchdog/pcwd_usb.c:336:22: error: ‘lsb’ is used uninitialized in this function [-Werror=uninitialized] *temperature = (lsb * 9 / 5) + 32; ~~~~^~~ drivers/watchdog/pcwd_usb.c:328:21: note: ‘lsb’ was declared here unsigned char msb, lsb; ^~~ cc1: all warnings being treated as errors scripts/Makefile.build:250: recipe for target 'drivers/watchdog/pcwd_usb.o' failed make[3]: *** [drivers/watchdog/pcwd_usb.o] Error 1 Fixes: b7e04f8c61a4 ("mv watchdog tree under drivers") Signed-off-by: Li Hua --- drivers/watchdog/pcwd_usb.c | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-) diff --git a/drivers/watchdog/pcwd_usb.c b/drivers/watchdog/pcwd_usb.c index 1bdaf17c1d38..89b0b5d8a7e6 100644 --- a/drivers/watchdog/pcwd_usb.c +++ b/drivers/watchdog/pcwd_usb.c @@ -326,8 +326,13 @@ static int usb_pcwd_get_temperature(struct usb_pcwd_private *usb_pcwd, int *temperature) { unsigned char msb, lsb; + int retval; - usb_pcwd_send_command(usb_pcwd, CMD_READ_TEMP, &msb, &lsb); + retval = usb_pcwd_send_command(usb_pcwd, CMD_READ_TEMP, &msb, &lsb); + if (retval != 1) { + pr_err("Card did not acknowledge CMD_READ_TEMP\n"); + return -1; + } /* * Convert celsius to fahrenheit, since this was @@ -342,10 +347,16 @@ static int usb_pcwd_get_timeleft(struct usb_pcwd_private *usb_pcwd, int *time_left) { unsigned char msb, lsb; + int retval; /* Read the time that's left before rebooting */ /* Note: if the board is not yet armed then we will read 0xFFFF */ - usb_pcwd_send_command(usb_pcwd, CMD_READ_WATCHDOG_TIMEOUT, &msb, &lsb); + retval = usb_pcwd_send_command(usb_pcwd, CMD_READ_WATCHDOG_TIMEOUT, + &msb, &lsb); + if (retval != 1) { + pr_err("Card did not acknowledge CMD_READ_WATCHDOG_TIMEOUT\n"); + return -1; + } *time_left = (msb << 8) + lsb;