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=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,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 DA327C65C20 for ; Mon, 8 Oct 2018 13:28:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9668E20841 for ; Mon, 8 Oct 2018 13:28:53 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9668E20841 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=pengutronix.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726616AbeJHUkf (ORCPT ); Mon, 8 Oct 2018 16:40:35 -0400 Received: from metis.ext.pengutronix.de ([85.220.165.71]:45707 "EHLO metis.ext.pengutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726065AbeJHUkf (ORCPT ); Mon, 8 Oct 2018 16:40:35 -0400 Received: from lupine.hi.pengutronix.de ([2001:67c:670:100:3ad5:47ff:feaf:1a17] helo=lupine) by metis.ext.pengutronix.de with esmtp (Exim 4.89) (envelope-from ) id 1g9Vab-0005V7-Ai; Mon, 08 Oct 2018 15:28:49 +0200 Message-ID: <1539005329.11512.26.camel@pengutronix.de> Subject: Re: [PATCH] reset: Fix potential use-after-free in __of_reset_control_get() From: Philipp Zabel To: Geert Uytterhoeven Cc: Geert Uytterhoeven , Linux Kernel Mailing List , "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" Date: Mon, 08 Oct 2018 15:28:49 +0200 In-Reply-To: References: <20181008111435.25994-1-geert+renesas@glider.be> <1539003375.11512.19.camel@pengutronix.de> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.22.6-1+deb9u1 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit X-SA-Exim-Connect-IP: 2001:67c:670:100:3ad5:47ff:feaf:1a17 X-SA-Exim-Mail-From: p.zabel@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-kernel@vger.kernel.org Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2018-10-08 at 15:12 +0200, Geert Uytterhoeven wrote: > Hi Philipp, > > On Mon, Oct 8, 2018 at 2:56 PM Philipp Zabel wrote: > > On Mon, 2018-10-08 at 13:14 +0200, Geert Uytterhoeven wrote: > > > Calling of_node_put() decreases the reference count of a device tree > > > object, and may free some data. > > > > > > However, the of_phandle_args structure embedding it is passed to > > > reset_controller_dev.of_xlate() after that, so it may still be accessed. > > > > > > Move the call to of_node_put() down to fix this. > > > > > > Signed-off-by: Geert Uytterhoeven > > > --- > > > drivers/reset/core.c | 15 ++++++++------- > > > 1 file changed, 8 insertions(+), 7 deletions(-) > > > > > > diff --git a/drivers/reset/core.c b/drivers/reset/core.c > > > index 225e34c56b94a2e3..bc9df10d31b4bae1 100644 > > > --- a/drivers/reset/core.c > > > +++ b/drivers/reset/core.c > > > @@ -496,27 +496,28 @@ struct reset_control *__of_reset_control_get(struct device_node *node, [...] > > > /* reset_list_mutex also protects the rcdev's reset_control list */ > > > rstc = __reset_control_get_internal(rcdev, rstc_id, shared); > > > > > > +out: > > > + of_node_put(args.np); > > > mutex_unlock(&reset_list_mutex); > > > > Thank you for the patch. I'd like to move of_node_put after mutex_unlock > > for symmetry. If you agree, I can switch the two when applying. > > No objection, thanks! Applied to reset/next with that change. regards Philipp