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=-6.7 required=3.0 tests=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 945B2C38A2A for ; Fri, 8 May 2020 21:25:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 68F75217BA for ; Fri, 8 May 2020 21:25:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727082AbgEHVZX (ORCPT ); Fri, 8 May 2020 17:25:23 -0400 Received: from mx2.suse.de ([195.135.220.15]:34058 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726811AbgEHVZX (ORCPT ); Fri, 8 May 2020 17:25:23 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 77347AF37; Fri, 8 May 2020 21:25:24 +0000 (UTC) From: NeilBrown To: syzbot , anna.schumaker@netapp.com, bfields@fieldses.org, chuck.lever@oracle.com, linux-kernel@vger.kernel.org, linux-nfs@vger.kernel.org, syzkaller-bugs@googlegroups.com, trond.myklebust@hammerspace.com Date: Sat, 09 May 2020 07:25:11 +1000 Subject: [PATCH] SUNRPC: fix use-after-free in rpc_free_client_work() In-Reply-To: <000000000000925dda05a50b9c13@google.com> References: <000000000000925dda05a50b9c13@google.com> Message-ID: <87r1vuazm0.fsf@notabene.neil.brown.name> MIME-Version: 1.0 Content-Type: multipart/signed; boundary="=-=-="; micalg=pgp-sha256; protocol="application/pgp-signature" Sender: linux-nfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org --=-=-= Content-Type: text/plain Content-Transfer-Encoding: quoted-printable Parts of rpc_free_client() were recently moved to a separate rpc_free_clent_work(). This introduced a use-after-free as rpc_clnt_remove_pipedir() calls rpc_net_ns(), and that uses clnt->cl_xprt which has already been freed. So move the call to xprt_put() after the call to rpc_clnt_remove_pipedir(). Reported-by: syzbot+22b5ef302c7c40d94ea8@syzkaller.appspotmail.com Fixes: 7c4310ff5642 ("SUNRPC: defer slow parts of rpc_free_client() to a wo= rkqueue.") Signed-off-by: NeilBrown =2D-- net/sunrpc/clnt.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c index 8350d3a2e9a7..8d3972ea688b 100644 =2D-- a/net/sunrpc/clnt.c +++ b/net/sunrpc/clnt.c @@ -890,6 +890,7 @@ static void rpc_free_client_work(struct work_struct *wo= rk) */ rpc_clnt_debugfs_unregister(clnt); rpc_clnt_remove_pipedir(clnt); + xprt_put(rcu_dereference_raw(clnt->cl_xprt)); =20 kfree(clnt); rpciod_down(); @@ -907,7 +908,6 @@ rpc_free_client(struct rpc_clnt *clnt) rpc_unregister_client(clnt); rpc_free_iostats(clnt->cl_metrics); clnt->cl_metrics =3D NULL; =2D xprt_put(rcu_dereference_raw(clnt->cl_xprt)); xprt_iter_destroy(&clnt->cl_xpi); put_cred(clnt->cl_cred); rpc_free_clid(clnt); =2D-=20 2.26.2 --=-=-= Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAEBCAAdFiEEG8Yp69OQ2HB7X0l6Oeye3VZigbkFAl61zjgACgkQOeye3VZi gblVlw/8CCtC/Q5JSGk4ecudVzz/GotzZtcL+ayh2Qx3YDzyCOkvqaSIiDF1s88m 8Tz+KYodZvdxFt157sv3JZ4SK5kIvNgy2UaCMhO3VqBc//9DOsGaRfWlT0kq6LWA 0hzwEiYLpIHjw2zBmC8Y2tMdoU2rg/OVXphuNXfESOWHFTdeQ8Scj5n4wer0E2/n RG/Glj3kKWBa6W7bjYhR+LHuF+7ufmqqCkd20t/iYGkfwQB+kI9qMpS7N7SAI3zX Csx7TZaYnEeENKC8igA+8IUcq3smlh9j6BnF+F3YI+5gAHqis+9bOSbpAIVoBKHm xkQLc+r+QP7OP+3diZZwptwWqB2oS4Slk/BtM2F4K53PUjnv4HnEjFal4Yo2MXRW rDrL0YLdJuVebiYoxzm/Wqcnn9xQxizAfn6RpTLMabGiHzjQeg7CKRzAPcY7Stv3 PfZ6T2ojmS4Xy8B0Ba4vtpzKdzC3o4IYYvtyAbr+pjw8OyEw8qSo9BPAvINS2ELE bV5NSzAVUCToOMNzuPUUlZEf2MeZvRfrMXUaKSwX79y8okDm7CHKgE5+tE+PKaic xFUh3wLhKIbAuM8CREMv98zCba8WIsrjPYCaoJQkE1e+lY2wtzmMmCZzXzHkhTWq o4Q65yrtHCV5anwW72GjUPCDp089jOpKWXsnulhPUVDjSlJ/ERA= =mg24 -----END PGP SIGNATURE----- --=-=-=--