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=-9.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 1886BC4741F for ; Mon, 9 Nov 2020 09:34:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B6D2F20719 for ; Mon, 9 Nov 2020 09:34:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729071AbgKIJeM (ORCPT ); Mon, 9 Nov 2020 04:34:12 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44932 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726176AbgKIJeM (ORCPT ); Mon, 9 Nov 2020 04:34:12 -0500 Received: from smtp3-1.goneo.de (smtp3.goneo.de [IPv6:2001:1640:5::8:37]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2FC4CC0613CF for ; Mon, 9 Nov 2020 01:34:12 -0800 (PST) Received: from localhost (localhost [127.0.0.1]) by smtp3.goneo.de (Postfix) with ESMTP id C282723EEDC; Mon, 9 Nov 2020 10:34:10 +0100 (CET) X-Virus-Scanned: by goneo Received: from smtp3.goneo.de ([127.0.0.1]) by localhost (smtp3.goneo.de [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id m8iLppu4mIMG; Mon, 9 Nov 2020 10:34:09 +0100 (CET) Received: from lem-wkst-02.lemonage (hq.lemonage.de [87.138.178.34]) by smtp3.goneo.de (Postfix) with ESMTPSA id 378B923F3C7; Mon, 9 Nov 2020 10:34:09 +0100 (CET) Date: Mon, 9 Nov 2020 10:34:01 +0100 From: Lars Poeschel To: Dan Carpenter Cc: Miguel Ojeda Sandonis , linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org Subject: Re: [PATCH] auxdisplay: fix use after free in lcd2s_i2c_remove() Message-ID: <20201109093401.oufzm5z3kcckloks@lem-wkst-02.lemonage> References: <20201106192415.GA2696904@mwanda> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20201106192415.GA2696904@mwanda> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Nov 06, 2020 at 10:24:15PM +0300, Dan Carpenter wrote: > The kfree() needs to be moved down a line to prevent a use after free. > > Fixes: 8c9108d014c5 ("auxdisplay: add a driver for lcd2s character display") > Signed-off-by: Dan Carpenter > --- > drivers/auxdisplay/lcd2s.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/auxdisplay/lcd2s.c b/drivers/auxdisplay/lcd2s.c > index cfa5f86deeef..3eb7f04db6cb 100644 > --- a/drivers/auxdisplay/lcd2s.c > +++ b/drivers/auxdisplay/lcd2s.c > @@ -348,8 +348,8 @@ static int lcd2s_i2c_remove(struct i2c_client *i2c) > { > struct lcd2s_data *lcd2s = i2c_get_clientdata(i2c); > > - kfree(lcd2s->charlcd); > charlcd_unregister(lcd2s->charlcd); > + kfree(lcd2s->charlcd); > return 0; > } Reviewed-by: Lars Pöschel Thanks, Lars