From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from outgoing.mit.edu (outgoing-auth-1.mit.edu [18.9.28.11]) (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 2071F60B9C for ; Fri, 17 May 2024 19:37:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=18.9.28.11 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1715974634; cv=none; b=Ojz4uPOK7wPBECipNQ9HGZTkgeS3necDUzNTvUobciZDygaw2vZF1DYWTTE/k8+I1Zpcp72OwI2xkPoh9D+WTmuMGrUgnX36pfDszkNnzFPawndKXNXB0pEm6IznCEgAeAZEgnBcBB6DqiefbuDIFfpPvBgYC+JQZN5uOhQc1L0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1715974634; c=relaxed/simple; bh=JAA8iSyx6bgiRG8Ddo2k0qxje0uyk0tV5RfZ/HiAvnk=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=JpAffXwXunOaolORqjcakYoZjEJ20veQnb9Tqun5X5aHBR7+OlrgCEfUglMo3nGqeXd4VBZ5RUnm1phr6OOsc8YVWuasgzlTyRnZkco4NnehTUd/TzrCdw7w3uk5yFBCVhbCcToPcQG6tWoLh+/gG3ntvOKn3Q11bQdnY1NfY+U= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=mit.edu; spf=pass smtp.mailfrom=mit.edu; dkim=pass (2048-bit key) header.d=mit.edu header.i=@mit.edu header.b=EclpJ7PQ; arc=none smtp.client-ip=18.9.28.11 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=mit.edu Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=mit.edu Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=mit.edu header.i=@mit.edu header.b="EclpJ7PQ" Received: from cwcc.thunk.org (pool-173-48-113-2.bstnma.fios.verizon.net [173.48.113.2]) (authenticated bits=0) (User authenticated as tytso@ATHENA.MIT.EDU) by outgoing.mit.edu (8.14.7/8.12.4) with ESMTP id 44HJaevV011512 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 17 May 2024 15:36:41 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=mit.edu; s=outgoing; t=1715974602; bh=art33/7wTYbQAOP1A+9aiHxSsPpImcDO5odsBbbfpUQ=; h=Date:From:Subject:Message-ID:MIME-Version:Content-Type; b=EclpJ7PQjaegxz8wu5lKouYqK1JbiU4EjkVr+hWch040PZby/TBfP1l1T7G9Ayisx viipOADDd+813uFUK7KcegkdN8stsYl7MtSldKfeudFInaciKEVKGdeodtg8Dl2eGQ U5DI2kA0ISW2iYIX8BcTV4JJyiwHIzhq3wwnkzfzDikMnzkYLG/nnGNB9Q7mpdOP+B Km6IBJZ4PE/yx4kiExEQvBJmpXoi6fDy8Ad8ZbpRaJ02w/KItoBMxUTNqbv1ZCQlLs WVqJ2wQXUbyUFS6GFJ2NXVhFVcLQ7T5AvLfEe3YwTWEimpYgP1e6lkN3gXgjeblySd w/NjYcktGc0fw== Received: by cwcc.thunk.org (Postfix, from userid 15806) id D12E415C00DC; Fri, 17 May 2024 15:36:39 -0400 (EDT) Date: Fri, 17 May 2024 15:36:39 -0400 From: "Theodore Ts'o" To: "Darrick J. Wong" Cc: Christoph Hellwig , Eric Biggers , aalbersh@redhat.com, linux-xfs@vger.kernel.org, alexl@redhat.com, walters@verbum.org, fsverity@lists.linux.dev, linux-fsdevel@vger.kernel.org Subject: Re: [PATCH 25/26] xfs: make it possible to disable fsverity Message-ID: <20240517193639.GA65648@mit.edu> References: <20240501225007.GM360919@frogsfrogsfrogs> <20240502001501.GB1853833@google.com> <20240508203148.GE360919@frogsfrogsfrogs> <20240509144542.GJ360919@frogsfrogsfrogs> <20240509150955.GL360919@frogsfrogsfrogs> <20240509154323.GM360919@frogsfrogsfrogs> Precedence: bulk X-Mailing-List: linux-fsdevel@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: <20240509154323.GM360919@frogsfrogsfrogs> On Thu, May 09, 2024 at 08:43:23AM -0700, Darrick J. Wong wrote: > > Well, fsverity as-is is intended for use cases where you care about > > integrity of the file. For that disabling it really doesn't make > > sense. If we have other use cases we can probably add a variant > > of fsverity that clearly deals with non-integrity checksums. > > Although just disabling them if they mismatch still feels like a > > somewhat odd usage model. > > Yeah, it definitely exists in the same weird grey area of turning off > metadata checksum validation to extract as many files from a busted fs > as can be done. I've certainly thought about the possibilities of adding a CRC checksum type. We do need to explicitly mark this as a non-cryptographic checksum since it might have make a difference for IMA policies, etc. This would be useful for detecting problems for people's video or music archives, for example. I can imagine situations where it might make sense to allow the file owner to be able to disable fsverity, whether the checksum and use case involves cryptographic or non-cryptographic checksums. Having a flag in the fsverity header indicating whether dropping fsverity protection requires elevated privileged or can be done by the file owner seems to make sense to me. - Ted