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=-10.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable 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 2C207C43460 for ; Mon, 19 Apr 2021 21:29:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id ECB57613AE for ; Mon, 19 Apr 2021 21:29:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240454AbhDSVaD (ORCPT ); Mon, 19 Apr 2021 17:30:03 -0400 Received: from jabberwock.ucw.cz ([46.255.230.98]:46346 "EHLO jabberwock.ucw.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229714AbhDSVaC (ORCPT ); Mon, 19 Apr 2021 17:30:02 -0400 Received: by jabberwock.ucw.cz (Postfix, from userid 1017) id 4CE431C0B7A; Mon, 19 Apr 2021 23:29:31 +0200 (CEST) Date: Mon, 19 Apr 2021 23:29:30 +0200 From: Pavel Machek To: Greg Kroah-Hartman Cc: linux-kernel@vger.kernel.org, stable@vger.kernel.org, Aditya Pakki , Santosh Shilimkar , "David S. Miller" , Sasha Levin Subject: Re: [PATCH 5.10 042/103] net/rds: Avoid potential use after free in rds_send_remove_from_sock Message-ID: <20210419212930.GA6626@amd> References: <20210419130527.791982064@linuxfoundation.org> <20210419130529.251281725@linuxfoundation.org> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="ReaqsoxgOBHFXBhH" Content-Disposition: inline In-Reply-To: <20210419130529.251281725@linuxfoundation.org> User-Agent: Mutt/1.5.23 (2014-03-12) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --ReaqsoxgOBHFXBhH Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hi! > [ Upstream commit 0c85a7e87465f2d4cbc768e245f4f45b2f299b05 ] >=20 > In case of rs failure in rds_send_remove_from_sock(), the 'rm' resource > is freed and later under spinlock, causing potential use-after-free. > Set the free pointer to NULL to avoid undefined behavior. This patch is crazy. Take a look at Message-ID: <20210419084953.GA28564@amd>. Or just look at the patch :-). Best regards, Pavel > +++ b/net/rds/message.c > @@ -180,6 +180,7 @@ void rds_message_put(struct rds_message *rm) > rds_message_purge(rm); > =20 > kfree(rm); > + rm =3D NULL; > } > } > EXPORT_SYMBOL_GPL(rds_message_put); > diff --git a/net/rds/send.c b/net/rds/send.c > index 985d0b7713ac..fe5264b9d4b3 100644 > --- a/net/rds/send.c > +++ b/net/rds/send.c > @@ -665,7 +665,7 @@ static void rds_send_remove_from_sock(struct list_hea= d *messages, int status) > unlock_and_drop: > spin_unlock_irqrestore(&rm->m_rs_lock, flags); > rds_message_put(rm); > - if (was_on_sock) > + if (was_on_sock && rm) > rds_message_put(rm); > } > =20 --=20 DENX Software Engineering GmbH, Managing Director: Wolfgang Denk HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany --ReaqsoxgOBHFXBhH Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iEYEARECAAYFAmB99joACgkQMOfwapXb+vIAGQCgnL84YaGH4RnXJ87ZuqGryccv qM0AoMJI8M8nrmObS7svKsM+A4zKVp2Q =Ms63 -----END PGP SIGNATURE----- --ReaqsoxgOBHFXBhH--