From owner-freebsd-fs@FreeBSD.ORG  Sat Mar 28 21:41:19 2015
Return-Path: <owner-freebsd-fs@FreeBSD.ORG>
Delivered-To: freebsd-fs@freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org
 [IPv6:2001:1900:2254:206a::19:1])
 (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits))
 (No client certificate requested)
 by hub.freebsd.org (Postfix) with ESMTPS id 67958A3
 for <freebsd-fs@freebsd.org>; Sat, 28 Mar 2015 21:41:19 +0000 (UTC)
Received: from hergotha.csail.mit.edu
 (wollman-1-pt.tunnel.tserv4.nyc4.ipv6.he.net [IPv6:2001:470:1f06:ccb::2])
 (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits))
 (Client did not present a certificate)
 by mx1.freebsd.org (Postfix) with ESMTPS id 24934D98
 for <freebsd-fs@freebsd.org>; Sat, 28 Mar 2015 21:41:18 +0000 (UTC)
Received: from hergotha.csail.mit.edu (localhost [127.0.0.1])
 by hergotha.csail.mit.edu (8.14.9/8.14.9) with ESMTP id t2SLfGgo044831
 for <freebsd-fs@freebsd.org>; Sat, 28 Mar 2015 17:41:16 -0400 (EDT)
 (envelope-from wollman@hergotha.csail.mit.edu)
Received: (from wollman@localhost)
 by hergotha.csail.mit.edu (8.14.9/8.14.4/Submit) id t2SLfGWl044828;
 Sat, 28 Mar 2015 17:41:16 -0400 (EDT) (envelope-from wollman)
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit
Message-ID: <21783.8188.747673.152040@hergotha.csail.mit.edu>
Date: Sat, 28 Mar 2015 17:41:16 -0400
From: Garrett Wollman <wollman@bimajority.org>
To: freebsd-fs@freebsd.org
Subject: Serious overflow/signedness issue in NFS server
X-Mailer: VM 7.17 under 21.4 (patch 22) "Instant Classic" XEmacs Lucid
X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.4.3
 (hergotha.csail.mit.edu [127.0.0.1]); Sat, 28 Mar 2015 17:41:16 -0400 (EDT)
X-Spam-Status: No, score=-1.0 required=5.0 tests=ALL_TRUSTED,
 HEADER_FROM_DIFFERENT_DOMAINS autolearn=disabled version=3.4.0
X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on
 hergotha.csail.mit.edu
X-BeenThere: freebsd-fs@freebsd.org
X-Mailman-Version: 2.1.18-1
Precedence: list
List-Id: Filesystems <freebsd-fs.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/options/freebsd-fs>,
 <mailto:freebsd-fs-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-fs/>
List-Post: <mailto:freebsd-fs@freebsd.org>
List-Help: <mailto:freebsd-fs-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-fs>,
 <mailto:freebsd-fs-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Sat, 28 Mar 2015 21:41:19 -0000

Yesterday I upgraded my production NFS servers to 10.1 from 9.3.
Very quickly, my users ran into the kernel RPC's buffer space
throttling mechanism.  Besides having a stupidly low and arbitrary
hard-coded limit, this code also has overflow bugs which which were
exposed by the switch to clang as the system compiler.

Please have a look at <https://reviews.freebsd.org/D2165> for what I
think is going to be the fix, and if you have a FreeBSD phabricator
account, please sign on as a reviewer.

I'm sure there are other lingering overflow bugs in this code.

-GAWollman