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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 267A1C433F5 for ; Mon, 3 Jan 2022 17:28:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233216AbiACR2z (ORCPT ); Mon, 3 Jan 2022 12:28:55 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53026 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229992AbiACR2z (ORCPT ); Mon, 3 Jan 2022 12:28:55 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 073AAC061761; Mon, 3 Jan 2022 09:28:55 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 84AB0B80E66; Mon, 3 Jan 2022 17:28:53 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9F787C36AEB; Mon, 3 Jan 2022 17:28:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1641230932; bh=zw1NdbOtkyijo7fXN+XvLZTKIYt/6pYw8B0XdMToLBU=; h=From:To:Cc:Subject:Date:From; b=NQfiROXpLiIqG0IxOaTU5uq8Qi1snYHst6D9tJdAEZvQ6dbu+T9rIPqaHBSHVprTQ nAVAAsw++k1DTAm3gL0gzL3aI2uBBqMliXqPygsOPgqdlsuMzEIHbs+yGKSbCGpduL 8IOrlsHBzLUimq1jjpr9BrVp9ywjoNggfL9y+kQV1wt9Dg1th4J4MxbeJq0wTPdP4l Nz/AqOpgGxNMQhX7tNPMdsHFV77XTFXtkQ2OoHvfXuaAYaR0lSONEqj4hAjIJMGeA6 0NLsLQcI9zG3hyZo2mrQGqW/E9cvM5HfVrxjU24LawpOzQPtuP6S5Gvbx8Rb14zkLW RrxkmS+eQ9jng== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Luiz Sampaio , Miguel Ojeda , Sasha Levin Subject: [PATCH AUTOSEL 5.15 01/16] auxdisplay: charlcd: checking for pointer reference before dereferencing Date: Mon, 3 Jan 2022 12:28:34 -0500 Message-Id: <20220103172849.1612731-1-sashal@kernel.org> X-Mailer: git-send-email 2.34.1 MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Luiz Sampaio [ Upstream commit 4daa9ff89ef27be43c15995412d6aee393a78200 ] 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 Signed-off-by: Miguel Ojeda Signed-off-by: Sasha Levin --- drivers/auxdisplay/charlcd.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/auxdisplay/charlcd.c b/drivers/auxdisplay/charlcd.c index 304accde365c8..6c010d4efa4ae 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 (WARN_ON(!lcd->ops->init_display)) + return -EINVAL; + ret = lcd->ops->init_display(lcd); if (ret) return ret; -- 2.34.1