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 X-Spam-Level: X-Spam-Status: No, score=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 18E12C433FF for ; Wed, 7 Aug 2019 09:00:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E752022305 for ; Wed, 7 Aug 2019 09:00:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725940AbfHGJAL (ORCPT ); Wed, 7 Aug 2019 05:00:11 -0400 Received: from mga11.intel.com ([192.55.52.93]:3024 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725891AbfHGJAL (ORCPT ); Wed, 7 Aug 2019 05:00:11 -0400 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from orsmga002.jf.intel.com ([10.7.209.21]) by fmsmga102.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 07 Aug 2019 02:00:10 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.64,357,1559545200"; d="scan'208";a="185927601" Received: from smile.fi.intel.com (HELO smile) ([10.237.68.145]) by orsmga002.jf.intel.com with ESMTP; 07 Aug 2019 02:00:09 -0700 Received: from andy by smile with local (Exim 4.92.1) (envelope-from ) id 1hvHnj-0005sm-Rd; Wed, 07 Aug 2019 12:00:07 +0300 Date: Wed, 7 Aug 2019 12:00:07 +0300 From: Andy Shevchenko To: "J. Bruce Fields" Cc: linux-nfs@vger.kernel.org Subject: Re: [PATCH 08/16] nfsd: escape high characters in binary data Message-ID: <20190807090007.GK30120@smile.fi.intel.com> References: <1561042275-12723-1-git-send-email-bfields@redhat.com> <1561042275-12723-9-git-send-email-bfields@redhat.com> <20190806121931.GA29578@smile.fi.intel.com> <20190806185008.GC9456@parsley.fieldses.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190806185008.GC9456@parsley.fieldses.org> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-nfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org On Tue, Aug 06, 2019 at 02:50:08PM -0400, J. Bruce Fields wrote: > On Tue, Aug 06, 2019 at 03:19:31PM +0300, Andy Shevchenko wrote: > > On Thu, Jun 20, 2019 at 10:51:07AM -0400, J. Bruce Fields wrote: > > > From: "J. Bruce Fields" > > > > > > I'm exposing some information about NFS clients in pseudofiles. I > > > expect to eventually have simple tools to help read those pseudofiles. > > > > > > But it's also helpful if the raw files are human-readable to the extent > > > possible. It aids debugging and makes them usable on systems that don't > > > have the latest nfs-utils. > > > > > > A minor challenge there is opaque client-generated protocol objects like > > > state owners and client identifiers. Some clients generate those to > > > include handy information in plain ascii. But they may also include > > > arbitrary byte sequences. > > > > > > I think the simplest approach is to limit to isprint(c) && isascii(c) > > > and escape everything else. > > > > > > That means you can just cat the file and get something that looks OK. > > > Also, I'm trying to keep these files legal YAML, which requires them to > > > UTF-8, and this is a simple way to guarantee that. > > > > Two questions: > > - why can't be original function extended to cover this case > > (using additional flags, maybe)? > > I found the ESCAPE_NP/"only" logic made it a little difficult to extend > string_escape_mem(). Maybe it requires more thinking about? I think it is still possible to extend existing, rather to take workarounds like this one. > So, I wrote a patch series that removes the string_escape_mem flags that > aren't used Have you considered the potential users that can be converted to use string_escape_mem()? I know about at least one (needs to be reworked a bit, but it is in slow progress). There are potentially others that would be converted using "unused" flags. >, simplifies it a bit, then separates the flags into two > different types: those that select which characters to escape > (non-printable, non-ascii, whitespace, etc.) and those that choose a > style of escaping to use (octal, hex, or \\). That seems to make the > code a little easier to extend while still covering the cases people > actually use. I'll try to get those out this week and you can tell me > what you think. Will be glad to help! In any case regarding to this one, I would like rather to see it's never appeared, or now will be gone in favour of string_escape_mem() extension. -- With Best Regards, Andy Shevchenko