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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 49BC6C19F2C for ; Tue, 2 Aug 2022 13:30:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233356AbiHBNav (ORCPT ); Tue, 2 Aug 2022 09:30:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34762 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233142AbiHBNau (ORCPT ); Tue, 2 Aug 2022 09:30:50 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DCCE81707C for ; Tue, 2 Aug 2022 06:30:48 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 3EE98612CF for ; Tue, 2 Aug 2022 13:30:48 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3769CC433C1; Tue, 2 Aug 2022 13:30:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1659447047; bh=V7YgclhDBrvWsuine6tiNhPVA45+HP55IICMmZXWP/4=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=udfttrtu8aS2GXePGe23VpNSOB0JAx6YUpi3VLCoFcZj53HVrRLm7n5v3ySo13QzX jUS+Wp3uMPiRUjyskc2W7Y7WVMlSirBRwYLI0PiAmNZYp9RMNReqVqyJ1lS2Orp7kA gDZR0kqIZz2nDSVZK4Pw9bBNtK2x8gHGLFogoZjw2U0scrbFeyaxLCCbMbrfb1LsBf UroMymbvgvspQel76P7Cnl5G8JZJRmUxlzkYGzNhraU2btblAxdC8iW2uPXyZG1JPr mPl98dUIdmFpne3TpzJ73os33nrVkd6YoGk8gskIRYQHuRemi5pm8YWhd5148882ZD om093mzAwZA1A== Message-ID: <0a456cb7d59353e4d22c7e04f15ce2b71348a32b.camel@kernel.org> Subject: Re: [PATCH v2] NFSD: fix use-after-free on source server when doing inter-server copy From: Jeff Layton To: Dai Ngo , chuck.lever@oracle.com, olga.kornievskaia@gmail.com Cc: linux-nfs@vger.kernel.org Date: Tue, 02 Aug 2022 09:30:45 -0400 In-Reply-To: <1659405154-21910-1-git-send-email-dai.ngo@oracle.com> References: <1659405154-21910-1-git-send-email-dai.ngo@oracle.com> Content-Type: text/plain; charset="ISO-8859-15" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.44.3 (3.44.3-1.fc36) MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org On Mon, 2022-08-01 at 18:52 -0700, Dai Ngo wrote: > Use-after-free occurred when the laundromat tried to free expired > cpntf_state entry on the s2s_cp_stateids list after inter-server > copy completed. The sc_cp_list that the expired copy state was > inserted on was already freed. >=20 > When COPY completes, the Linux client normally sends LOCKU(lock_state x), > FREE_STATEID(lock_state x) and CLOSE(open_state y) to the source server. > The nfs4_put_stid call from nfsd4_free_stateid cleans up the copy state > from the s2s_cp_stateids list before freeing the lock state's stid. >=20 > However, sometimes the CLOSE was sent before the FREE_STATEID request. > When this happens, the nfsd4_close_open_stateid call from nfsd4_close > frees all lock states on its st_locks list without cleaning up the copy > state on the sc_cp_list list. When the time the FREE_STATEID arrives the > server returns BAD_STATEID since the lock state was freed. This causes > the use-after-free error to occur when the laundromat tries to free > the expired cpntf_state. >=20 > This patch adds a call to nfs4_free_cpntf_statelist in > nfsd4_close_open_stateid to clean up the copy state before calling > free_ol_stateid_reaplist to free the lock state's stid on the reaplist. >=20 > Signed-off-by: Dai Ngo > --- > fs/nfsd/nfs4state.c | 7 +++++++ > 1 file changed, 7 insertions(+) >=20 > diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c > index 9409a0dc1b76..b99c545f93e4 100644 > --- a/fs/nfsd/nfs4state.c > +++ b/fs/nfsd/nfs4state.c > @@ -1049,6 +1049,9 @@ static struct nfs4_ol_stateid * nfs4_alloc_open_sta= teid(struct nfs4_client *clp) > =20 > static void nfs4_free_deleg(struct nfs4_stid *stid) > { > + struct nfs4_ol_stateid *stp =3D openlockstateid(stid); > + > + WARN_ON(!list_empty(&stp->st_stid.sc_cp_list)); > kmem_cache_free(deleg_slab, stid); > atomic_long_dec(&num_delegations); > } > @@ -1463,6 +1466,7 @@ static void nfs4_free_ol_stateid(struct nfs4_stid *= stid) > release_all_access(stp); > if (stp->st_stateowner) > nfs4_put_stateowner(stp->st_stateowner); > + WARN_ON(!list_empty(&stp->st_stid.sc_cp_list)); > kmem_cache_free(stateid_slab, stid); > } > =20 > @@ -6608,6 +6612,7 @@ static void nfsd4_close_open_stateid(struct nfs4_ol= _stateid *s) > struct nfs4_client *clp =3D s->st_stid.sc_client; > bool unhashed; > LIST_HEAD(reaplist); > + struct nfs4_ol_stateid *stp; > =20 > spin_lock(&clp->cl_lock); > unhashed =3D unhash_open_stateid(s, &reaplist); > @@ -6616,6 +6621,8 @@ static void nfsd4_close_open_stateid(struct nfs4_ol= _stateid *s) > if (unhashed) > put_ol_stateid_locked(s, &reaplist); > spin_unlock(&clp->cl_lock); > + list_for_each_entry(stp, &reaplist, st_locks) > + nfs4_free_cpntf_statelist(clp->net, &stp->st_stid); > free_ol_stateid_reaplist(&reaplist); > } else { > spin_unlock(&clp->cl_lock); Reviewed-by: Jeff Layton