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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no 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 F3D37C433E1 for ; Wed, 13 May 2020 21:03:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0A0E0207DF for ; Wed, 13 May 2020 21:03:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727030AbgEMVDO (ORCPT ); Wed, 13 May 2020 17:03:14 -0400 Received: from jabberwock.ucw.cz ([46.255.230.98]:51200 "EHLO jabberwock.ucw.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725952AbgEMVDN (ORCPT ); Wed, 13 May 2020 17:03:13 -0400 Received: by jabberwock.ucw.cz (Postfix, from userid 1017) id 088FC1C0285; Wed, 13 May 2020 23:03:12 +0200 (CEST) Date: Wed, 13 May 2020 23:03:11 +0200 From: Pavel Machek To: Greg Kroah-Hartman Cc: linux-kernel@vger.kernel.org, stable@vger.kernel.org, Xiyu Yang , Xin Tan , Sven Eckelmann , Simon Wunderlich Subject: Re: [PATCH 4.19 35/48] batman-adv: Fix refcnt leak in batadv_store_throughput_override Message-ID: <20200513210311.GA1822@duo.ucw.cz> References: <20200513094351.100352960@linuxfoundation.org> <20200513094400.720293748@linuxfoundation.org> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="FCuugMFkClbJLl1L" Content-Disposition: inline In-Reply-To: <20200513094400.720293748@linuxfoundation.org> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --FCuugMFkClbJLl1L Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hi! > From: Xiyu Yang >=20 > commit 6107c5da0fca8b50b4d3215e94d619d38cc4a18c upstream. >=20 > batadv_show_throughput_override() invokes batadv_hardif_get_by_netdev(), > which gets a batadv_hard_iface object from net_dev with increased refcnt > and its reference is assigned to a local pointer 'hard_iface'. >=20 > When batadv_store_throughput_override() returns, "hard_iface" becomes > invalid, so the refcount should be decreased to keep refcount balanced. >=20 > The issue happens in one error path of > batadv_store_throughput_override(). When batadv_parse_throughput() > returns NULL, the refcnt increased by batadv_hardif_get_by_netdev() is > not decreased, causing a refcnt leak. >=20 > Fix this issue by jumping to "out" label when batadv_parse_throughput() > returns NULL. Ok, this fixes the issue, but it brings up a question: > --- a/net/batman-adv/sysfs.c > +++ b/net/batman-adv/sysfs.c > @@ -1093,7 +1093,7 @@ static ssize_t batadv_store_throughput_o > ret =3D batadv_parse_throughput(net_dev, buff, "throughput_override", > &tp_override); > if (!ret) > - return count; > + goto out; > If parsing of value from userspace failed we are currently returning success. That seems wrong. Should we return -EINVAL instead? Best regards, Pavel --=20 (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blo= g.html --FCuugMFkClbJLl1L Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iF0EABECAB0WIQRPfPO7r0eAhk010v0w5/Bqldv68gUCXrxgjwAKCRAw5/Bqldv6 8jBxAKCPatfcX8F+QT4Xyocp9Z5aK5zspQCfeBHvHJ78hSvs+RqKA0ND11ZVfKs= =SVkw -----END PGP SIGNATURE----- --FCuugMFkClbJLl1L--