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=-20.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=unavailable 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 3CEBFC07E9D for ; Mon, 19 Jul 2021 15:57:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 17F89613F1 for ; Mon, 19 Jul 2021 15:57:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1346173AbhGSPOL (ORCPT ); Mon, 19 Jul 2021 11:14:11 -0400 Received: from mail.kernel.org ([198.145.29.99]:40442 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1344207AbhGSOsm (ORCPT ); Mon, 19 Jul 2021 10:48:42 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 2445161403; Mon, 19 Jul 2021 15:26:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1626708416; bh=alClgonaliYo7bbQrEoXPOwyF03/KVXnqZEw2BqJkKM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=KwSxR5p0gLZq3IQdw7JmMR9nElBfMwJNCDn74FMSIt80m/uMgPioQHBMjpgQGlsQK laML7Dr1hOBDh9dsNBWjPGrGsPrTeREggUz8Nn9pk15/2xKvkqrOMPtrMPcJcIaDMO bwWu0eMcyKgE27FRESWiVNxzBxcC/pUbca1QJm/E= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Dan Carpenter , Alexandre Belloni , Sasha Levin Subject: [PATCH 4.14 303/315] rtc: fix snprintf() checking in is_rtc_hctosys() Date: Mon, 19 Jul 2021 16:53:12 +0200 Message-Id: <20210719144953.430307490@linuxfoundation.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210719144942.861561397@linuxfoundation.org> References: <20210719144942.861561397@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Dan Carpenter [ Upstream commit 54b909436ede47e0ee07f1765da27ec2efa41e84 ] The scnprintf() function silently truncates the printf() and returns the number bytes that it was able to copy (not counting the NUL terminator). Thus, the highest value it can return here is "NAME_SIZE - 1" and the overflow check is dead code. Fix this by using the snprintf() function which returns the number of bytes that would have been copied if there was enough space and changing the condition from "> NAME_SIZE" to ">= NAME_SIZE". Fixes: 92589c986b33 ("rtc-proc: permit the /proc/driver/rtc device to use other devices") Signed-off-by: Dan Carpenter Signed-off-by: Alexandre Belloni Link: https://lore.kernel.org/r/YJov/pcGmhLi2pEl@mwanda Signed-off-by: Sasha Levin --- drivers/rtc/rtc-proc.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/rtc/rtc-proc.c b/drivers/rtc/rtc-proc.c index 31e7e23cc5be..9396b69f75e8 100644 --- a/drivers/rtc/rtc-proc.c +++ b/drivers/rtc/rtc-proc.c @@ -26,8 +26,8 @@ static bool is_rtc_hctosys(struct rtc_device *rtc) int size; char name[NAME_SIZE]; - size = scnprintf(name, NAME_SIZE, "rtc%d", rtc->id); - if (size > NAME_SIZE) + size = snprintf(name, NAME_SIZE, "rtc%d", rtc->id); + if (size >= NAME_SIZE) return false; return !strncmp(name, CONFIG_RTC_HCTOSYS_DEVICE, NAME_SIZE); -- 2.30.2