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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS autolearn=unavailable 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 CC80FC282CE for ; Tue, 12 Feb 2019 14:45:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A402A2083B for ; Tue, 12 Feb 2019 14:45:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730194AbfBLOpC (ORCPT ); Tue, 12 Feb 2019 09:45:02 -0500 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:48450 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730018AbfBLOpB (ORCPT ); Tue, 12 Feb 2019 09:45:01 -0500 Received: from pps.filterd (m0098394.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x1CEhsQA061532 for ; Tue, 12 Feb 2019 09:45:00 -0500 Received: from e06smtp07.uk.ibm.com (e06smtp07.uk.ibm.com [195.75.94.103]) by mx0a-001b2d01.pphosted.com with ESMTP id 2qkyk3sxx4-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Tue, 12 Feb 2019 09:45:00 -0500 Received: from localhost by e06smtp07.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Tue, 12 Feb 2019 14:44:53 -0000 Received: from d06av24.portsmouth.uk.ibm.com (mk.ibm.com [9.149.105.60]) by b06cxnps3075.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x1CEiqOr43581624 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Tue, 12 Feb 2019 14:44:52 GMT Received: from d06av24.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 721184203F; Tue, 12 Feb 2019 14:44:52 +0000 (GMT) Received: from d06av24.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 026B942041; Tue, 12 Feb 2019 14:44:50 +0000 (GMT) Received: from localhost.localdomain (unknown [9.80.91.85]) by d06av24.portsmouth.uk.ibm.com (Postfix) with ESMTP; Tue, 12 Feb 2019 14:44:49 +0000 (GMT) Subject: Re: Proposal: Yet another possible fs-verity interface From: Mimi Zohar To: "Theodore Y. Ts'o" , Linus Torvalds Cc: Dave Chinner , Christoph Hellwig , "Darrick J. Wong" , Eric Biggers , linux-fscrypt@vger.kernel.org, linux-fsdevel , linux-ext4@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net Date: Tue, 12 Feb 2019 09:44:39 -0500 In-Reply-To: <20190212051237.GQ23000@mit.edu> References: <20190207031101.GA7387@mit.edu> <20190212051237.GQ23000@mit.edu> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.20.5 (3.20.5-1.fc24) Mime-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 x-cbid: 19021214-0028-0000-0000-00000347B03A X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19021214-0029-0000-0000-00002405D054 Message-Id: <1549982679.12743.248.camel@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-02-12_08:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1902120107 Sender: linux-ext4-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org > At that point, the merkle tree thing ends up fairly equivalent to the > > IMA "measurement" thing, with the exception that the filesystem *may* > > optimize it to be long-term. Hmm? > > Well, except that it's just a less efficient way of doing IMA > "measurement" (if the file system doesn't support Merkle tree > storage). > > So adding that complexity is, in my view, not really worth it, since I > very much doubt anyone would use a slower scheme. I think the much > better model is that fsverity is for file system where you can store > the Merkle tree (and it's really not that hard for most file systems > to store it); and if you are using a file system which doesn't, use > IMA in good health. Ted, one of the problems with IMA is that the file hash/signature verification is at file open.  It isn't aware when files are brought in from cache.  Does fs-verity re-verify blocks as they're restored from cache?  For some use cases, that might justify the up front cost associated with building the Merkle tree. Mimi From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mimi Zohar Subject: Re: Proposal: Yet another possible fs-verity interface Date: Tue, 12 Feb 2019 09:44:39 -0500 Message-ID: <1549982679.12743.248.camel@linux.ibm.com> References: <20190207031101.GA7387@mit.edu> <20190212051237.GQ23000@mit.edu> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Return-path: Received: from [172.30.20.202] (helo=mx.sourceforge.net) by sfs-ml-1.v29.lw.sourceforge.com with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.90_1) (envelope-from ) id 1gtZJ6-0005NX-BB for linux-f2fs-devel@lists.sourceforge.net; Tue, 12 Feb 2019 14:45:08 +0000 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]) by sfi-mx-1.v28.lw.sourceforge.com with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.90_1) id 1gtZJ3-00AWH4-PU for linux-f2fs-devel@lists.sourceforge.net; Tue, 12 Feb 2019 14:45:08 +0000 Received: from pps.filterd (m0098410.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x1CEiLBB015236 for ; Tue, 12 Feb 2019 09:45:00 -0500 Received: from e06smtp07.uk.ibm.com (e06smtp07.uk.ibm.com [195.75.94.103]) by mx0a-001b2d01.pphosted.com with ESMTP id 2qkww9pejr-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Tue, 12 Feb 2019 09:44:59 -0500 Received: from localhost by e06smtp07.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 12 Feb 2019 14:44:57 -0000 In-Reply-To: <20190212051237.GQ23000@mit.edu> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: linux-f2fs-devel-bounces@lists.sourceforge.net To: "Theodore Y. Ts'o" , Linus Torvalds Cc: Eric Biggers , "Darrick J. Wong" , Dave Chinner , linux-f2fs-devel@lists.sourceforge.net, Christoph Hellwig , linux-fscrypt@vger.kernel.org, linux-fsdevel , linux-ext4@vger.kernel.org PiBBdCB0aGF0IHBvaW50LCB0aGUgbWVya2xlIHRyZWUgdGhpbmcgZW5kcyB1cCBmYWlybHkgZXF1 aXZhbGVudCB0bwp0aGUKPiA+IElNQSAibWVhc3VyZW1lbnQiIHRoaW5nLCB3aXRoIHRoZSBleGNl cHRpb24gdGhhdCB0aGUgZmlsZXN5c3RlbSAqbWF5Kgo+ID4gb3B0aW1pemUgaXQgdG8gYmUgbG9u Zy10ZXJtLiBIbW0/Cj4gCj4gV2VsbCwgZXhjZXB0IHRoYXQgaXQncyBqdXN0IGEgbGVzcyBlZmZp Y2llbnQgd2F5IG9mIGRvaW5nIElNQQo+ICJtZWFzdXJlbWVudCIgKGlmIHRoZSBmaWxlIHN5c3Rl bSBkb2Vzbid0IHN1cHBvcnQgTWVya2xlIHRyZWUKPiBzdG9yYWdlKS4KPiAKPiBTbyBhZGRpbmcg dGhhdCBjb21wbGV4aXR5IGlzLCBpbiBteSB2aWV3LCBub3QgcmVhbGx5IHdvcnRoIGl0LCBzaW5j ZSBJCj4gdmVyeSBtdWNoIGRvdWJ0IGFueW9uZSB3b3VsZCB1c2UgYSBzbG93ZXIgc2NoZW1lLiAg SSB0aGluayB0aGUgbXVjaAo+IGJldHRlciBtb2RlbCBpcyB0aGF0IGZzdmVyaXR5IGlzIGZvciBm aWxlIHN5c3RlbSB3aGVyZSB5b3UgY2FuIHN0b3JlCj4gdGhlIE1lcmtsZSB0cmVlIChhbmQgaXQn cyByZWFsbHkgbm90IHRoYXQgaGFyZCBmb3IgbW9zdCBmaWxlIHN5c3RlbXMKPiB0byBzdG9yZSBp dCk7IGFuZCBpZiB5b3UgYXJlIHVzaW5nIGEgZmlsZSBzeXN0ZW0gd2hpY2ggZG9lc24ndCwgdXNl Cj4gSU1BIGluIGdvb2QgaGVhbHRoLgoKVGVkLCBvbmUgb2YgdGhlIHByb2JsZW1zIHdpdGggSU1B IGlzIHRoYXQgdGhlIGZpbGUgaGFzaC9zaWduYXR1cmUKdmVyaWZpY2F0aW9uIGlzIGF0IGZpbGUg b3Blbi4gwqBJdCBpc24ndCBhd2FyZSB3aGVuIGZpbGVzIGFyZSBicm91Z2h0CmluIGZyb20gY2Fj aGUuIMKgRG9lcyBmcy12ZXJpdHkgcmUtdmVyaWZ5IGJsb2NrcyBhcyB0aGV5J3JlIHJlc3RvcmVk CmZyb20gY2FjaGU/IMKgRm9yIHNvbWUgdXNlIGNhc2VzLCB0aGF0IG1pZ2h0IGp1c3RpZnkgdGhl IHVwIGZyb250IGNvc3QKYXNzb2NpYXRlZCB3aXRoIGJ1aWxkaW5nIHRoZSBNZXJrbGUgdHJlZS4K Ck1pbWkKCgoKX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX18K TGludXgtZjJmcy1kZXZlbCBtYWlsaW5nIGxpc3QKTGludXgtZjJmcy1kZXZlbEBsaXN0cy5zb3Vy Y2Vmb3JnZS5uZXQKaHR0cHM6Ly9saXN0cy5zb3VyY2Vmb3JnZS5uZXQvbGlzdHMvbGlzdGluZm8v bGludXgtZjJmcy1kZXZlbAo=