From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755277Ab2ARWlO (ORCPT ); Wed, 18 Jan 2012 17:41:14 -0500 Received: from fieldses.org ([174.143.236.118]:35510 "EHLO fieldses.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755214Ab2ARWlL (ORCPT ); Wed, 18 Jan 2012 17:41:11 -0500 Date: Wed, 18 Jan 2012 17:41:08 -0500 From: "J. Bruce Fields" To: Dan Carpenter Cc: Sasha Levin , linux-kernel@vger.kernel.org, Neil Brown , linux-nfs@vger.kernel.org Subject: Re: [patch] nfsd: don't allow zero length strings in cache_parse() Message-ID: <20120118224107.GC27205@fieldses.org> References: <1321611289-21809-1-git-send-email-levinsasha928@gmail.com> <20120116115258.GC3294@mwanda> <20120116155031.GC1750@fieldses.org> <20120118095601.GE3356@mwanda> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20120118095601.GE3356@mwanda> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jan 18, 2012 at 12:56:02PM +0300, Dan Carpenter wrote: > There is no point in passing a zero length string here and quite a > few of that cache_parse() implementations will Oops if count is > zero. Thanks, I'll apply. Could we clean up any checks in cache_parse() that are unnecessary now? --b. > > Signed-off-by: Dan Carpenter > > diff --git a/net/sunrpc/cache.c b/net/sunrpc/cache.c > index 465df9a..8c6598e 100644 > --- a/net/sunrpc/cache.c > +++ b/net/sunrpc/cache.c > @@ -828,6 +828,8 @@ static ssize_t cache_do_downcall(char *kaddr, const char __user *buf, > { > ssize_t ret; > > + if (count == 0) > + return -EINVAL; > if (copy_from_user(kaddr, buf, count)) > return -EFAULT; > kaddr[count] = '\0';