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 04038C433EF for ; Mon, 11 Oct 2021 13:50:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E5BA061040 for ; Mon, 11 Oct 2021 13:50:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237602AbhJKNwE (ORCPT ); Mon, 11 Oct 2021 09:52:04 -0400 Received: from mail.kernel.org ([198.145.29.99]:39356 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237361AbhJKNvJ (ORCPT ); Mon, 11 Oct 2021 09:51:09 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 3B2DE61056; Mon, 11 Oct 2021 13:48:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1633960138; bh=qQ1MSWuaX5GKaoeukYrLPxRqvuiM40+VmOg6aGJbrpY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ZVI7tvPJij1irXpJrLjD4IvC/L4wXem5KKQTWvAUdnQozHhGn/ZMjSFu3yKXvWZhL FhCbE3FGHhwcQ3himgpkBa7S5uX3TuvSLR1dnZiO4cDagqQo2f6xLtSnxTUazWSXtA wphtRMiMV2ihu1yJnLF/8BaK//h2IQAowgPer9IE= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Trond Myklebust , Chuck Lever Subject: [PATCH 5.4 09/52] nfsd4: Handle the NFSv4 READDIR dircount hint being zero Date: Mon, 11 Oct 2021 15:45:38 +0200 Message-Id: <20211011134504.034986456@linuxfoundation.org> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20211011134503.715740503@linuxfoundation.org> References: <20211011134503.715740503@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: linux-kernel@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 @@ -3131,15 +3131,18 @@ 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: