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 7735DC31E40 for ; Tue, 6 Aug 2019 18:50:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4E8FF20818 for ; Tue, 6 Aug 2019 18:50:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725973AbfHFSuK (ORCPT ); Tue, 6 Aug 2019 14:50:10 -0400 Received: from mx1.redhat.com ([209.132.183.28]:38104 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725798AbfHFSuK (ORCPT ); Tue, 6 Aug 2019 14:50:10 -0400 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 48D2C315C01E; Tue, 6 Aug 2019 18:50:10 +0000 (UTC) Received: from parsley.fieldses.org (ovpn-116-185.phx2.redhat.com [10.3.116.185]) by smtp.corp.redhat.com (Postfix) with ESMTP id 0FC425C559; Tue, 6 Aug 2019 18:50:10 +0000 (UTC) Received: by parsley.fieldses.org (Postfix, from userid 2815) id CA2E61804A0; Tue, 6 Aug 2019 14:50:08 -0400 (EDT) Date: Tue, 6 Aug 2019 14:50:08 -0400 From: "J. Bruce Fields" To: Andy Shevchenko Cc: linux-nfs@vger.kernel.org Subject: Re: [PATCH 08/16] nfsd: escape high characters in binary data Message-ID: <20190806185008.GC9456@parsley.fieldses.org> 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> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190806121931.GA29578@smile.fi.intel.com> User-Agent: Mutt/1.12.0 (2019-05-25) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.41]); Tue, 06 Aug 2019 18:50:10 +0000 (UTC) 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 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(). So, I wrote a patch series that removes the string_escape_mem flags that aren't used, 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. > - where are the test cases? I didn't write a test case. I agree that it would be a good idea--I'll work on it. --b.