Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964792AbWESSqd (ORCPT ); Fri, 19 May 2006 14:46:33 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S964795AbWESSqd (ORCPT ); Fri, 19 May 2006 14:46:33 -0400 Received: from citi.umich.edu ([141.211.133.111]:12990 "EHLO citi.umich.edu") by vger.kernel.org with ESMTP id S964792AbWESSqd (ORCPT ); Fri, 19 May 2006 14:46:33 -0400 Message-ID: <446E1287.4070200@citi.umich.edu> Date: Fri, 19 May 2006 14:46:31 -0400 From: Chuck Lever Reply-To: cel@citi.umich.edu Organization: Center for Information Technology Integration User-Agent: Thunderbird 1.5.0.2 (Macintosh/20060308) MIME-Version: 1.0 To: Andrew Morton Cc: cel@netapp.com, linux-kernel@vger.kernel.org, trond.myklebust@fys.uio.no, Badari Pulavarty Subject: Re: [PATCH 5/6] nfs: check all iov segments for correct memory access rights References: <20060519175652.3244.7079.stgit@brahms.dsl.sfldmi.ameritech.net> <20060519180036.3244.70897.stgit@brahms.dsl.sfldmi.ameritech.net> <20060519112231.5ed3d565.akpm@osdl.org> In-Reply-To: <20060519112231.5ed3d565.akpm@osdl.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1403 Lines: 42 Andrew Morton wrote: > Chuck Lever wrote: >> +static ssize_t check_access_ok(int type, const struct iovec *iov, unsigned long nr_segs) >> +{ >> + ssize_t count = 0; >> + ssize_t retval = -EINVAL; >> + unsigned long seg; >> + >> + for (seg = 0; seg < nr_segs; seg++) { >> + void __user *buf = iov[seg].iov_base; >> + ssize_t len = (ssize_t) iov[seg].iov_len; >> + >> + if (len < 0) /* size_t not fitting an ssize_t .. */ >> + goto out; > > do_readv_writev() already checked for negative iov_len, and that's the more > appropriate place to do it, rather than duplicating it in each filesystem > (or forgetting to!) > > So is this check really needed? Ok, didn't see that function before. Badari, is this checking still needed? >> + if (unlikely(!access_ok(type, buf, len))) { >> + retval = -EFAULT; >> + goto out; >> + } > > Now what's up here? Why does NFS, at this level, care about the page's > virtual address? get_user_pages() will handle that? Interesting point. That may be a historical artifact that can be removed. I'll take a look. -- corporate: cel at netapp dot com personal: chucklever at bigfoot dot com - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/