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=-8.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 448FFC32750 for ; Tue, 30 Jul 2019 23:03:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 20DAA20679 for ; Tue, 30 Jul 2019 23:03:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726712AbfG3XDk (ORCPT ); Tue, 30 Jul 2019 19:03:40 -0400 Received: from fieldses.org ([173.255.197.46]:41902 "EHLO fieldses.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726343AbfG3XDk (ORCPT ); Tue, 30 Jul 2019 19:03:40 -0400 Received: by fieldses.org (Postfix, from userid 2815) id DADB82010; Tue, 30 Jul 2019 19:03:39 -0400 (EDT) Date: Tue, 30 Jul 2019 19:03:39 -0400 From: "J. Bruce Fields" To: Jia-Ju Bai Cc: chuck.lever@oracle.com, linux-nfs@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] fs: nfsd: Fix three possible null-pointer dereferences Message-ID: <20190730230339.GD3544@fieldses.org> References: <20190724082803.1077-1-baijiaju1990@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190724082803.1077-1-baijiaju1990@gmail.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-nfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org On Wed, Jul 24, 2019 at 04:28:03PM +0800, Jia-Ju Bai wrote: > In nfs4_xdr_dec_cb_recall(), nfs4_xdr_dec_cb_layout() and > nfs4_xdr_dec_cb_notify_lock(), there is an if statement to check whether > cb is NULL. > > When cb is NULL, the three functions all call: > decode_cb_op_status(..., &cb->cb_status); > > Thus, possible null-pointer dereferences may occur. > > To fix these possible bugs, -EINVAL is returned when cb is NULL. > > These bugs are found by a static analysis tool STCheck written by us. Thanks! But I think actually the correct fix is just to remove the NULL checks entirely. --b. > > Signed-off-by: Jia-Ju Bai > --- > fs/nfsd/nfs4callback.c | 11 ++++++++--- > 1 file changed, 8 insertions(+), 3 deletions(-) > > diff --git a/fs/nfsd/nfs4callback.c b/fs/nfsd/nfs4callback.c > index 397eb7820929..55949a158b6b 100644 > --- a/fs/nfsd/nfs4callback.c > +++ b/fs/nfsd/nfs4callback.c > @@ -516,7 +516,8 @@ static int nfs4_xdr_dec_cb_recall(struct rpc_rqst *rqstp, > status = decode_cb_sequence4res(xdr, cb); > if (unlikely(status || cb->cb_seq_status)) > return status; > - } > + } else > + return -EINVAL; > > return decode_cb_op_status(xdr, OP_CB_RECALL, &cb->cb_status); > } > @@ -608,7 +609,9 @@ static int nfs4_xdr_dec_cb_layout(struct rpc_rqst *rqstp, > status = decode_cb_sequence4res(xdr, cb); > if (unlikely(status || cb->cb_seq_status)) > return status; > - } > + } else > + return -EINVAL; > + > return decode_cb_op_status(xdr, OP_CB_LAYOUTRECALL, &cb->cb_status); > } > #endif /* CONFIG_NFSD_PNFS */ > @@ -667,7 +670,9 @@ static int nfs4_xdr_dec_cb_notify_lock(struct rpc_rqst *rqstp, > status = decode_cb_sequence4res(xdr, cb); > if (unlikely(status || cb->cb_seq_status)) > return status; > - } > + } else > + return -EINVAL; > + > return decode_cb_op_status(xdr, OP_CB_NOTIFY_LOCK, &cb->cb_status); > } > > -- > 2.17.0