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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D2A54C433F5 for ; Mon, 11 Oct 2021 14:14:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C1D7660C49 for ; Mon, 11 Oct 2021 14:14:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243986AbhJKOQu (ORCPT ); Mon, 11 Oct 2021 10:16:50 -0400 Received: from mail.kernel.org ([198.145.29.99]:34948 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243377AbhJKOOn (ORCPT ); Mon, 11 Oct 2021 10:14:43 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 8489A61177; Mon, 11 Oct 2021 14:04:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1633961094; bh=0MDKaSEaNK55zglKbOL+auRaeQ7qIQHTinkUGZ0UK0E=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=slgUfDjFVgcx3Ez0+MHCx+/tupSe+jFMO8DefYtL89rNGivyCzWr4dcF6ORkITzh6 p68ubngFXS6IDiOOcFWZNzwXU9MA09kqidkDVSGjiwFo05Xa22x/4i/SsKOwje5VfO awaxSv7tgX8BUulOStpVMAqKClj3mhQqNhwr2iyo= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Trond Myklebust , Chuck Lever Subject: [PATCH 4.19 06/28] nfsd4: Handle the NFSv4 READDIR dircount hint being zero Date: Mon, 11 Oct 2021 15:46:56 +0200 Message-Id: <20211011134640.916263507@linuxfoundation.org> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20211011134640.711218469@linuxfoundation.org> References: <20211011134640.711218469@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Trond Myklebust commit f2e717d655040d632c9015f19aa4275f8b16e7f2 upstream. RFC3530 notes that the 'dircount' field may be zero, in which case the recommendation is to ignore it, and only enforce the 'maxcount' field. In RFC5661, this recommendation to ignore a zero valued field becomes a requirement. Fixes: aee377644146 ("nfsd4: fix rd_dircount enforcement") Cc: Signed-off-by: Trond Myklebust Signed-off-by: Chuck Lever Signed-off-by: Greg Kroah-Hartman --- fs/nfsd/nfs4xdr.c | 19 +++++++++++-------- 1 file changed, 11 insertions(+), 8 deletions(-) --- a/fs/nfsd/nfs4xdr.c +++ b/fs/nfsd/nfs4xdr.c @@ -3124,15 +3124,18 @@ nfsd4_encode_dirent(void *ccdv, const ch goto fail; cd->rd_maxcount -= entry_bytes; /* - * RFC 3530 14.2.24 describes rd_dircount as only a "hint", so - * let's always let through the first entry, at least: + * RFC 3530 14.2.24 describes rd_dircount as only a "hint", and + * notes that it could be zero. If it is zero, then the server + * should enforce only the rd_maxcount value. */ - if (!cd->rd_dircount) - goto fail; - name_and_cookie = 4 + 4 * XDR_QUADLEN(namlen) + 8; - if (name_and_cookie > cd->rd_dircount && cd->cookie_offset) - goto fail; - cd->rd_dircount -= min(cd->rd_dircount, name_and_cookie); + if (cd->rd_dircount) { + name_and_cookie = 4 + 4 * XDR_QUADLEN(namlen) + 8; + if (name_and_cookie > cd->rd_dircount && cd->cookie_offset) + goto fail; + cd->rd_dircount -= min(cd->rd_dircount, name_and_cookie); + if (!cd->rd_dircount) + cd->rd_maxcount = 0; + } cd->cookie_offset = cookie_offset; skip_entry: