From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 892FC16415 for ; Sun, 25 Feb 2024 17:03:05 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708880585; cv=none; b=MVLGjUkNefKL4gJbwKIgKdWnxtwDKvtDO/hOyBaNLfpfw7z+WxQQt5GmvXXBScGDiS9BydoKRekhbp6IKQ/dAqhaPG/MSqp3db4DsUkLTiknZR5ta93g7TO+Y2vV5KFfiMa6xzbKh493bfBasNWvj8jiA79wAzNTQUpvoU/vU6g= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708880585; c=relaxed/simple; bh=7y4WFcUZqhu2eoE6Mhi7ZtnR++wOlajGzudyraHHAYM=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=UKoP62DcdSdqztsE4Ptnpkc+tFs01fzq1irGVKFdraCJMHiRMJiqt49uuXvDIO/b1JrKsm9YFmmlhM5/nzK/oY6K7GeeIJh6/sXnSnBi2gDqutIs/F7OktoO8hD+NQ5BYTlHJdcJzhIJF7Zi/RrkEEQ7vgDWgX7REgdhfEQjI7o= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=cuyRCAkI; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="cuyRCAkI" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 01ADEC433F1; Sun, 25 Feb 2024 17:03:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1708880585; bh=7y4WFcUZqhu2eoE6Mhi7ZtnR++wOlajGzudyraHHAYM=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=cuyRCAkIrlaB505UFrIWjNoRI0ZfXFgi9254UlQvXaCLUqXusoaAGCWr3LBLm9D5V B77nFgWWUWIEbCgdchD5S/hdpn75DYuVi2UvG6h41reqDqSf7gq4c6yfVm6XozjEO/ z2Dtrkf8z9Ncfz6bOi/fq0Nu+bGbd3LPtwu4mavbdbYm7ih16B4pr98y2C3wp1ePBq vPx18xg5dWLHu5Vetz2GebJGUMqWqpIRxqpf1SL4TI72SKMGgik+r7CkWS5+iYlZXE 0eSfhaTl7SLlY6mHzMI5+0aZr3mqKHr/QTYlhP/MZBf5Lyrxu9nqbMRod5kq3GtbAd lDJVvom8hkaEg== Date: Sun, 25 Feb 2024 09:03:04 -0800 From: "Darrick J. Wong" To: Eric Biggers Cc: Zorro Lang , David Sterba , fstests@vger.kernel.org Subject: Re: Dangerous commands (was:[ANNOUNCE] fstests: for-next branch updated to v2024.02.04) Message-ID: <20240225170304.GO6188@frogsfrogsfrogs> References: <20240221140951.GJ355@suse.cz> <20240225151616.owk5v4ioplhrioe6@dell-per750-06-vm-08.rhts.eng.pek2.redhat.com> <20240225165128.GA1128@sol.localdomain> Precedence: bulk X-Mailing-List: fstests@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240225165128.GA1128@sol.localdomain> On Sun, Feb 25, 2024 at 08:51:28AM -0800, Eric Biggers wrote: > On Sun, Feb 25, 2024 at 11:16:16PM +0800, Zorro Lang wrote: > > On Wed, Feb 21, 2024 at 03:09:51PM +0100, David Sterba wrote: > > > Hi, > > > > > > reading [1] and how late it was found that effectively a "rm -rf /" can > > > happen makes me worried about what I can expect from fstests after git > > > pull. Many people contribute and the number for custom _cleanup() > > > functions with unquoted 'rm' commands is just asking for more problems. > > > > > > [1] https://lore.kernel.org/all/20240205060016.7fgiyafbnrvf5chj@dell-per750-06-vm-08.rhts.eng.pek2.redhat.com/ > > > > > > Unquoted arguments in shell scripts is IMO a big anti-pattern, > > > unfortunately present everywhere in xfstests since the beginning. > > > Rewriting all scripts would be quite a lot of work, could you at least > > > provide safe versions of the cleanup helpers? > > > > Hi David, > > > > Thanks for taking care about it :) > > > > > > > > For example: > > > > > > _rm_tmp() { > > > rm -rf -- $tmp > > > > It's "$tmp.*" > > > > May I ask what problem does the "--" hope to avoid? If the "$tmp" is empty, > > "rm -rf" and "rm -rf --"" looks like both doing nothing. So what kind > > of situation does the "--" hope to fix? > > > > The root problem in above [1] is about "${FOO}*". If someone does "rm -rf ${FOO}*" > > in its custom _cleanup_xxxxx function, then it's dangerous if "$FOO" is empty. > > > > I thought some ways to avoid that: > > 1) Try to avoid doing rm -rf ${FOO}*, if not necessary. > > 2) Must checks [ -n "$FOO" ] before doing any rm -rf ${FOO}* > > 3) Someone's custom _cleanup_xxxxx better to be called before default _cleanup > > does "cd /". > > 4) Think about bringing in someone "Static program analysis" tool about bash > > script, but I don't know if there're someone good, feel free to give me > > suggestions. > > "--" prevents the following arguments from being interpreted as options if they > begin with "-". That's a good practice, but it doesn't help with ${FOO} being > empty. To cause the script to exit if ${FOO} is empty, it can be written as > ${FOO:?}. Alternatively, 'set -u' can be used. I said that four days ago. Did nobody receive that reply? https://lore.kernel.org/fstests/20240225165128.GA1128@sol.localdomain/T/#m0efd851c5a1fb0dbe418f4aff818d20f4355638b --D > - Eric >