From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752504AbdGMRHP (ORCPT ); Thu, 13 Jul 2017 13:07:15 -0400 Received: from casper.infradead.org ([85.118.1.10]:38226 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751157AbdGMRHO (ORCPT ); Thu, 13 Jul 2017 13:07:14 -0400 Date: Thu, 13 Jul 2017 18:07:07 +0100 (BST) From: James Simmons To: Arnd Bergmann cc: Oleg Drokin , Andreas Dilger , stable@vger.kernel.org, Greg Kroah-Hartman , Doug Oucharek , Dmitry Eremin , Al Viro , Liang Zhen , Nicholas Hanley , lustre-devel@lists.lustre.org, devel@driverdev.osuosl.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] lustre: check copy_from_iter/copy_to_iter return code In-Reply-To: <20170710130833.1834210-1-arnd@arndb.de> Message-ID: References: <20170710130833.1834210-1-arnd@arndb.de> User-Agent: Alpine 2.20 (LFD 67 2015-01-07) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20170713_180707_353968_EFE09419 X-CRM114-Status: GOOD ( 21.93 ) X-Spam-Score: -1.9 (-) X-Spam-Report: SpamAssassin version 3.4.1 on casper.infradead.org summary: Content analysis details: (-1.9 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- -0.0 NO_RELAYS Informational: message was not relayed via SMTP -1.9 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > We now get a helpful warning for code that calls copy_{from,to}_iter > without checking the return value, introduced by commit aa28de275a24 > ("iov_iter/hardening: move object size checks to inlined part"). > > drivers/staging/lustre/lnet/klnds/o2iblnd/o2iblnd_cb.c: In function 'kiblnd_send': > drivers/staging/lustre/lnet/klnds/o2iblnd/o2iblnd_cb.c:1643:2: error: ignoring return value of 'copy_from_iter', declared with attribute warn_unused_result [-Werror=unused-result] > drivers/staging/lustre/lnet/klnds/o2iblnd/o2iblnd_cb.c: In function 'kiblnd_recv': > drivers/staging/lustre/lnet/klnds/o2iblnd/o2iblnd_cb.c:1744:3: error: ignoring return value of 'copy_to_iter', declared with attribute warn_unused_result [-Werror=unused-result] > > In case we get short copies here, we may get incorrect behavior. > I've added failure handling for both rx and tx now, returning > -EFAULT as expected. > > Cc: stable@vger.kernel.org > Signed-off-by: Arnd Bergmann > --- > This warning now shows up in 'allmodconfig' builds, so it would be > good to get it fixed quickly for 4.13, but my patch should not go > in without careful review since I'm not familiar with with code > and the error handling is a bit tricky here. > > I added 'Cc: stable' since this is a preexisting condition that we > only started warning about now. > --- > drivers/staging/lustre/lnet/klnds/o2iblnd/o2iblnd_cb.c | 15 +++++++++++++-- > 1 file changed, 13 insertions(+), 2 deletions(-) > > diff --git a/drivers/staging/lustre/lnet/klnds/o2iblnd/o2iblnd_cb.c b/drivers/staging/lustre/lnet/klnds/o2iblnd/o2iblnd_cb.c > index 85b242ec5f9b..70256a0ffd2e 100644 > --- a/drivers/staging/lustre/lnet/klnds/o2iblnd/o2iblnd_cb.c > +++ b/drivers/staging/lustre/lnet/klnds/o2iblnd/o2iblnd_cb.c > @@ -1640,8 +1640,13 @@ kiblnd_send(struct lnet_ni *ni, void *private, struct lnet_msg *lntmsg) > ibmsg = tx->tx_msg; > ibmsg->ibm_u.immediate.ibim_hdr = *hdr; > > - copy_from_iter(&ibmsg->ibm_u.immediate.ibim_payload, IBLND_MSG_SIZE, > + rc = copy_from_iter(&ibmsg->ibm_u.immediate.ibim_payload, IBLND_MSG_SIZE, > &from); I have to Nak this to prevent it from landing but for some reason in my testing its returning zero from copy_from_iter. > + if (rc != IBLND_MSG_SIZE) { > + kiblnd_pool_free_node(&tx->tx_pool->tpo_pool, &tx->tx_list); > + return -EFAULT; > + } > + > nob = offsetof(struct kib_immediate_msg, ibim_payload[payload_nob]); > kiblnd_init_tx_msg(ni, tx, IBLND_MSG_IMMEDIATE, nob); > > @@ -1741,8 +1746,14 @@ kiblnd_recv(struct lnet_ni *ni, void *private, struct lnet_msg *lntmsg, > break; > } > > - copy_to_iter(&rxmsg->ibm_u.immediate.ibim_payload, > + rc = copy_to_iter(&rxmsg->ibm_u.immediate.ibim_payload, > IBLND_MSG_SIZE, to); > + if (rc != IBLND_MSG_SIZE) { > + rc = -EFAULT; > + break; > + } > + > + rc = 0; > lnet_finalize(ni, lntmsg, 0); > break; > > -- > 2.9.0 > >