From patchwork Fri Jul 2 15:37:51 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "J. Bruce Fields" X-Patchwork-Id: 12356327 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=-17.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,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 200E0C11F68 for ; Fri, 2 Jul 2021 15:37:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 09F4F610A1 for ; Fri, 2 Jul 2021 15:37:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232106AbhGBPkY (ORCPT ); Fri, 2 Jul 2021 11:40:24 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57046 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231883AbhGBPkX (ORCPT ); Fri, 2 Jul 2021 11:40:23 -0400 Received: from fieldses.org (fieldses.org [IPv6:2600:3c00:e000:2f7::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E6874C061762 for ; Fri, 2 Jul 2021 08:37:51 -0700 (PDT) Received: by fieldses.org (Postfix, from userid 2815) id 2646B6482; Fri, 2 Jul 2021 11:37:51 -0400 (EDT) DKIM-Filter: OpenDKIM Filter v2.11.0 fieldses.org 2646B6482 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fieldses.org; s=default; t=1625240271; bh=RMlGmxw1gL9vINTfmaaDQlB36HAck4fofdq2QwTDLfM=; h=Date:To:Cc:Subject:From:From; b=NVKy/i57vRHObguXY7ZZW12vmP/BGGBtpQGTAdVX997nICQABOgKetTCx+SC9sI21 1Gn8C5h8sXNHs09YtODhy1+ofmvHMXrUTmFlppSsNwzyRh0yOi104k/pfJjggt1Esd 25CpEqdg7Ts/mqECFjMjgA+3P+vUSnmZzzrNko3o= Date: Fri, 2 Jul 2021 11:37:51 -0400 To: linux-nfs@vger.kernel.org Cc: Chuck Lever Subject: [PATCH] nfsd: fix NULL dereference in nfs3svc_encode_getaclres Message-ID: <20210702153751.GA29685@fieldses.org> MIME-Version: 1.0 Content-Disposition: inline User-Agent: Mutt/1.5.21 (2010-09-15) From: bfields@fieldses.org (J. Bruce Fields) Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org From: "J. Bruce Fields" In error cases the dentry may be NULL. Before 20798dfe249a, the encoder also checked dentry and d_really_is_positive(dentry), but that looks like overkill to me--zero status should be enough to guarantee a positive dentry. This isn't the first time we've seen an error-case NULL dereference hidden in the initialization of a local variable in an xdr encoder. But I went back through the other recent rewrites and didn't spot any similar bugs. Reported-by: JianHong Yin Fixes: 20798dfe249a ("NFSD: Update the NFSv3 GETACL result encoder...") Signed-off-by: J. Bruce Fields Reviewed-by: Chuck Lever --- fs/nfsd/nfs3acl.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/fs/nfsd/nfs3acl.c b/fs/nfsd/nfs3acl.c index a1591feeea22..5dfe7644a517 100644 --- a/fs/nfsd/nfs3acl.c +++ b/fs/nfsd/nfs3acl.c @@ -172,7 +172,7 @@ static int nfs3svc_encode_getaclres(struct svc_rqst *rqstp, __be32 *p) struct nfsd3_getaclres *resp = rqstp->rq_resp; struct dentry *dentry = resp->fh.fh_dentry; struct kvec *head = rqstp->rq_res.head; - struct inode *inode = d_inode(dentry); + struct inode *inode; unsigned int base; int n; int w; @@ -181,6 +181,7 @@ static int nfs3svc_encode_getaclres(struct svc_rqst *rqstp, __be32 *p) return 0; switch (resp->status) { case nfs_ok: + inode = d_inode(dentry); if (!svcxdr_encode_post_op_attr(rqstp, xdr, &resp->fh)) return 0; if (xdr_stream_encode_u32(xdr, resp->mask) < 0)