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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C14E4C433EF for ; Sun, 7 Nov 2021 15:03:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9F98260E78 for ; Sun, 7 Nov 2021 15:03:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235586AbhKGPGC (ORCPT ); Sun, 7 Nov 2021 10:06:02 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40058 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235571AbhKGPF4 (ORCPT ); Sun, 7 Nov 2021 10:05:56 -0500 Received: from mail-qt1-x831.google.com (mail-qt1-x831.google.com [IPv6:2607:f8b0:4864:20::831]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B4F1BC061570 for ; Sun, 7 Nov 2021 07:03:13 -0800 (PST) Received: by mail-qt1-x831.google.com with SMTP id x10so11215946qta.6 for ; Sun, 07 Nov 2021 07:03:13 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=ZdSkp/wjCjH5O8nJQPBwfhqtOJTZO7qRybqidn7xqBA=; b=OFQu6UKAT8zNIkDXt6usQzrm9MZ5u4HFFiXimPLU1FnWAtnYJNUfqnDtLqtp/bNXLt Cru/9gLN3BVKJi9n/CSXMF6yS0sypDc9Scqn8LF4cz+DFq7eGPkSivD51LMeoX5uFWk3 om+TEbJuJx3FYYsiTnSjA/4JsUR9UKGdrkbXyk51fexKW/EL7oqX9Cd+qMfVOFK/YDKU Q88nn4uWBLcHxkeYEMlvcKKTFba4vEjXL3g+IJ4R5rXZcVXUeAK2wIlvJQyiBLJOThvb lv5HlmgrnF/mh2nSSEupz5L2ypGX/hwb1RYv4KWkU81ykl4mXfkyu/S8oZx/Ju/qoRpB 8FlQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=ZdSkp/wjCjH5O8nJQPBwfhqtOJTZO7qRybqidn7xqBA=; b=rHuHMurea6+WtZMuBJrx4iFVc6TkhoYk8sC/qLz1TV7TNBjt2xVt/jg/XZRDQ6f9Ff iqp1VQxy7eo0GqVWQOddWD5RLF9nGaaxCS0RTP/0oEWu7M4JMDutWxRYB7+GRBHnXWg5 DNwi5u3+QopP6oCJ2v6xYr+Ikx8XuY2tJ17h4RtQN3FAjrvBCwPjWHpDcWLW+Rwyh8/E UuT5hbEwsJr4DQt9QfStXaV+yY2ghCrfc+w2CLglutql/9IxMv77nS/B4sKEHacJNz0N XYOaHXClavG0qPxYwc3v70Iw2JMCQp3dULlG/jorJumLXQ/YXSoBz0HiHSX9AzwxTcsO gL4Q== X-Gm-Message-State: AOAM532kBOj7d3tfjBmMRliq8Kt6eU0JOKfyh+mBVr2WC8XXwLXep5U+ mXCkPbGhOEI539mvFynWLvZJj9qgy8Hz1yG0 X-Google-Smtp-Source: ABdhPJzenFbJJb0owKyIhCV+xlXslz167FOS0s9KT08aOA46dyUxREKX+4LNF+6Kd5MF7atyNmm6Sg== X-Received: by 2002:ac8:5c08:: with SMTP id i8mr77507150qti.181.1636297392982; Sun, 07 Nov 2021 07:03:12 -0800 (PST) Received: from thinkpad.localdomain ([2804:14d:5c21:92d0:fc01:11b0:47fa:d730]) by smtp.gmail.com with ESMTPSA id x11sm9554883qta.90.2021.11.07.07.03.11 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 07 Nov 2021 07:03:12 -0800 (PST) From: Luiz Sampaio To: ojeda@kernel.org Cc: linux-kernel@vger.kernel.org, Luiz Sampaio Subject: [PATCH 2/2] auxdisplay: charlcd: checking for pointer reference before dereferencing Date: Sun, 7 Nov 2021 12:03:04 -0300 Message-Id: <20211107150304.3253-3-sampaio.ime@gmail.com> X-Mailer: git-send-email 2.33.1 In-Reply-To: <20211107150304.3253-1-sampaio.ime@gmail.com> References: <20211107150304.3253-1-sampaio.ime@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Check if the pointer lcd->ops->init_display exists before dereferencing it. If a driver called charlcd_init() without defining the ops, this would return segmentation fault, as happened to me when implementing a charlcd driver. Checking the pointer before dereferencing protects from segmentation fault. Signed-off-by: Luiz Sampaio --- drivers/auxdisplay/charlcd.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/auxdisplay/charlcd.c b/drivers/auxdisplay/charlcd.c index cca3b600c0ba..47363fb2fe94 100644 --- a/drivers/auxdisplay/charlcd.c +++ b/drivers/auxdisplay/charlcd.c @@ -578,6 +578,9 @@ static int charlcd_init(struct charlcd *lcd) * Since charlcd_init_display() needs to write data, we have to * enable mark the LCD initialized just before. */ + if (!lcd->ops->init_display) + return -EFAULT; + ret = lcd->ops->init_display(lcd); if (ret) return ret; -- 2.33.1