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=-5.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,UNPARSEABLE_RELAY,URIBL_BLOCKED,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 2FC3BC433ED for ; Tue, 27 Apr 2021 11:13:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E06E4613CA for ; Tue, 27 Apr 2021 11:13:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235796AbhD0LNz (ORCPT ); Tue, 27 Apr 2021 07:13:55 -0400 Received: from bhuna.collabora.co.uk ([46.235.227.227]:57850 "EHLO bhuna.collabora.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230270AbhD0LNz (ORCPT ); Tue, 27 Apr 2021 07:13:55 -0400 Received: from [127.0.0.1] (localhost [127.0.0.1]) (Authenticated sender: shreeya) with ESMTPSA id ADD7E1F42573 Subject: Re: [PATCH] generic/453: Exclude filenames that are not supported by exfat To: Matthew Wilcox Cc: fstests@vger.kernel.org, linux-fsdevel@vger.kernel.org, krisman@collabora.com, preichl@redhat.com, kernel@collabora.com References: <20210425223105.1855098-1-shreeya.patel@collabora.com> <20210426003430.GH235567@casper.infradead.org> <20210426123734.GK235567@casper.infradead.org> From: Shreeya Patel Message-ID: Date: Tue, 27 Apr 2021 16:43:05 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.9.0 MIME-Version: 1.0 In-Reply-To: <20210426123734.GK235567@casper.infradead.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US Precedence: bulk List-ID: X-Mailing-List: fstests@vger.kernel.org On 26/04/21 6:07 pm, Matthew Wilcox wrote: > On Mon, Apr 26, 2021 at 05:27:51PM +0530, Shreeya Patel wrote: >> On 26/04/21 6:04 am, Matthew Wilcox wrote: >>> On Mon, Apr 26, 2021 at 04:01:05AM +0530, Shreeya Patel wrote: >>>> exFAT filesystem does not support the following character codes >>>> 0x0000 - 0x001F ( Control Codes ), /, ?, :, ", \, *, <, |, > >>> ummm ... >>> >>>> -# Fake slash? >>>> -setf "urk\xc0\xafmoo" "FAKESLASH" >>> That doesn't use any of the explained banned characters. It uses 0xc0, >>> 0xaf. >>> >>> Now, in utf-8, that's an nonconforming sequence. "The Unicode and UCS >>> standards require that producers of UTF-8 shall use the shortest form >>> possible, for example, producing a two-byte sequence with first byte 0xc0 >>> is nonconforming. Unicode 3.1 has added the requirement that conforming >>> programs must not accept non-shortest forms in their input." >>> >>> So is it that exfat is rejecting nonconforming sequences? Or is it >>> converting the nonconforming sequence from 0xc0 0xaf to the conforming >>> sequence 0x2f, and then rejecting it (because it's '/')? >>> >> No, I don't think exfat is not converting nonconforming sequence from 0xc0 >> 0xaf >> to the conforming sequence 0x2f. >> Because I get different outputs when tried with both ways. >> When I create a file with "urk\xc0\xafmoo", I get output as "Operation not >> permitted" >> and when I create it as "urk\x2fmoo", it gives "No such file or directory >> error" or >> you can consider this error as "Invalid argument" >> ( because that's what I get when I try for other characters like |, :, ?, >> etc ) > I think we need to understand this before skipping the test. Does it > also fail, eg, on cifs, vfat, jfs or udf? I tested it for VFAT, UDF and JFS and following are the results. 1. VFAT ( as per wikipedia 0x00-0x1F 0x7F " * / : < > ? \ | are reserved characters) For \x2f - /var/mnt/scratch/test-453/urk/moo.txt: No such file or directory For \xc0\xaf) - /var/mnt/scratch/test-453/urk��moo.txt: Invalid argument Also gives error for Box filename ( this is very much similar to exfat, the only difference is that I do not get Operation not permitted when using \xc0\xaf, instead it gives invalid argument.) 2. UDF ( as per wikipedia - only NULL cannot be used ) For \x2f - /var/mnt/scratch/test-453/urk/moo.txt: No such file or directory For \xc0\xaf - creates filename something like this 'urk??moo.txt' and does not throw any error. ( But this seems to be invalid and should have thrown some error) Also gives error for dotdot entry. I am not sure why UDF was giving error for / and dot dot entry but then I read the following for UDF in one of the man pages which justifies the above errors I think "Invalid characters such as "NULL" and "/" and  invalid  file names  such  as "." and ".." will be translated according to the following rule: Replace the invalid character with an "_," then  append  the file name with # followed by a 4 digit hex representation of the 16-bit CRC of the original FileIdentifier. For  example, the file name ".." will become "__#4C05" " Source - http://www-it.desy.de/cgi-bin/man-cgi?udfs+7 3. JFS ( as per Wikipedia NULL cannot be used ) For \x2f - /var/mnt/scratch/test-453/urk/moo.txt: No such file or directory For \xc0\xaf - Works fine Again not sure why / is failing here. Did not find much resource about the restricted filenames for JFS. So as per above all the results, it seems like using \x2f fails for all but \xc0\xaf does work for JFS. > >> Box filename also fails with "Invalid argument" error. >> >>