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=-7.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS 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 0AD57C43461 for ; Thu, 17 Sep 2020 16:34:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AF138214D8 for ; Thu, 17 Sep 2020 16:34:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600360456; bh=64guTUZ7EKPT2qpTc7D0yaFTflRcH4pcyFWo+xuAOGU=; h=Subject:From:To:Cc:Date:In-Reply-To:References:List-ID:From; b=WEaJI7PvGva8GjP4tDAGGNeIHI3QWqQE2Qe92QGbPUaqOC0IlhanbB31xE6/b4ez4 3OcfWyj2S9RKTRR0Ul94lkkVhusAqrAxXYbj5SNbWEHEBf/XtwPnb3fYOqdTXGQPlB wm/UvRu381V0loqnvMzN2cBU1YTm6yP/ZZII36rM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728576AbgIQQdx (ORCPT ); Thu, 17 Sep 2020 12:33:53 -0400 Received: from mail.kernel.org ([198.145.29.99]:43992 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728369AbgIQQdd (ORCPT ); Thu, 17 Sep 2020 12:33:33 -0400 Received: from tleilax.poochiereds.net (68-20-15-154.lightspeed.rlghnc.sbcglobal.net [68.20.15.154]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id C27D2214D8; Thu, 17 Sep 2020 16:33:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600360408; bh=64guTUZ7EKPT2qpTc7D0yaFTflRcH4pcyFWo+xuAOGU=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=eU1pP6hgmXz25xyBg9bazb9fKAso0aXmNP2dVveMx2ztmBwOjVdBVik39B9/dsfyi l7B1BELQj4b0ud+U4UFntHF3lCMR/Rq5xrFwpLL3OBQuZckdLAshp7dwLe0wC59tkq GBid0tzn4y03cySN4r38Z/i9cVEe43zaJsX5UFUA= Message-ID: <197468586b4a9b933755d2f9a462a234d654e280.camel@kernel.org> Subject: Re: [PATCH v3 13/13] fscrypt: make fscrypt_set_test_dummy_encryption() take a 'const char *' From: Jeff Layton To: Eric Biggers Cc: linux-fscrypt@vger.kernel.org, linux-ext4@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, linux-mtd@lists.infradead.org, ceph-devel@vger.kernel.org, Daniel Rosenberg Date: Thu, 17 Sep 2020 12:33:26 -0400 In-Reply-To: <20200917152907.GB855@sol.localdomain> References: <20200917041136.178600-1-ebiggers@kernel.org> <20200917041136.178600-14-ebiggers@kernel.org> <41ad3cd50f4d213455bef4e7c42143c289690222.camel@kernel.org> <20200917152907.GB855@sol.localdomain> Content-Type: text/plain; charset="UTF-8" User-Agent: Evolution 3.36.5 (3.36.5-1.fc32) MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: ceph-devel@vger.kernel.org On Thu, 2020-09-17 at 08:29 -0700, Eric Biggers wrote: > On Thu, Sep 17, 2020 at 08:32:39AM -0400, Jeff Layton wrote: > > On Wed, 2020-09-16 at 21:11 -0700, Eric Biggers wrote: > > > From: Eric Biggers > > > > > > fscrypt_set_test_dummy_encryption() requires that the optional argument > > > to the test_dummy_encryption mount option be specified as a substring_t. > > > That doesn't work well with filesystems that use the new mount API, > > > since the new way of parsing mount options doesn't use substring_t. > > > > > > Make it take the argument as a 'const char *' instead. > > > > > > Instead of moving the match_strdup() into the callers in ext4 and f2fs, > > > make them just use arg->from directly. Since the pattern is > > > "test_dummy_encryption=%s", the argument will be null-terminated. > > > > > > > Are you sure about that? I thought the point of substring_t was to give > > you a token from the string without null terminating it. > > > > ISTM that when you just pass in ->from, you might end up with trailing > > arguments in your string like this. e.g.: > > > > "v2,foo,bar,baz" > > > > ...and then that might fail to match properly > > in fscrypt_set_test_dummy_encryption. > > > > Yes I'm sure, and I had also tested it. The use of match_token() here is to > parse one null-terminated mount option at a time. > > The reason that match_token() can return multiple substrings is that the pattern > might be something like "foo=%d:%d". > > But here it's just "test_dummy_encryption=%s". "%s" matches until end-of-string. Got it. Thanks for explaining! -- Jeff Layton