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=-2.4 required=3.0 tests=DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,T_DKIM_INVALID, USER_AGENT_MUTT autolearn=ham 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 36883C433F5 for ; Fri, 24 Aug 2018 22:45:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CEFFD208EB for ; Fri, 24 Aug 2018 22:45:28 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=thunk.org header.i=@thunk.org header.b="WUX7zhmU" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CEFFD208EB Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=mit.edu Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727442AbeHYCWD (ORCPT ); Fri, 24 Aug 2018 22:22:03 -0400 Received: from imap.thunk.org ([74.207.234.97]:43548 "EHLO imap.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726564AbeHYCWD (ORCPT ); Fri, 24 Aug 2018 22:22:03 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=thunk.org; s=ef5046eb; h=In-Reply-To:Content-Type:MIME-Version:References:Message-ID: Subject:Cc:To:From:Date:Sender:Reply-To:Content-Transfer-Encoding:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=MW8Mo5WYV/jtB27uNo0lWYcPFClWZRNLFXHgrmRymlQ=; b=WUX7zhmUQaow2VmP74JlgUqwn7 jg6ziRYU7ErCPdtQ4By5qasGjzmfKXl6n2uknAMGx8Gi1NQHZap8jjvxQ71akcLM4ytmLNniw/IZz CN4EmXIkMkAs1fXbM3xfSTBa6Jkqx8FLFcRtyECA8QcCTOHVu1P6iEEwUQs95DAhY7qk=; Received: from root (helo=callcc.thunk.org) by imap.thunk.org with local-esmtp (Exim 4.89) (envelope-from ) id 1ftKpS-0005i4-8i; Fri, 24 Aug 2018 22:45:18 +0000 Received: by callcc.thunk.org (Postfix, from userid 15806) id 1A50B7A57A9; Fri, 24 Aug 2018 18:45:17 -0400 (EDT) Date: Fri, 24 Aug 2018 18:45:17 -0400 From: "Theodore Y. Ts'o" To: Colin Walters Cc: Eric Biggers , linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, linux-integrity@vger.kernel.org, linux-fscrypt@vger.kernel.org, linux-kernel@vger.kernel.org, Mimi Zohar , Dmitry Kasatkin , Michael Halcrow , Victor Hsieh Subject: Re: [RFC PATCH 01/10] fs-verity: add setup code, UAPI, and Kconfig Message-ID: <20180824224517.GF15262@thunk.org> Mail-Followup-To: "Theodore Y. Ts'o" , Colin Walters , Eric Biggers , linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, linux-integrity@vger.kernel.org, linux-fscrypt@vger.kernel.org, linux-kernel@vger.kernel.org, Mimi Zohar , Dmitry Kasatkin , Michael Halcrow , Victor Hsieh References: <20180824161642.1144-1-ebiggers@kernel.org> <20180824161642.1144-2-ebiggers@kernel.org> <1535132549.2855027.1485213752.129E3334@webmail.messagingengine.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1535132549.2855027.1485213752.129E3334@webmail.messagingengine.com> User-Agent: Mutt/1.10.1 (2018-07-13) X-SA-Exim-Connect-IP: X-SA-Exim-Mail-From: tytso@thunk.org X-SA-Exim-Scanned: No (on imap.thunk.org); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Aug 24, 2018 at 01:42:29PM -0400, Colin Walters wrote: > > While I'm not too familiar with the vfs, as far as I can > tell from inspection of Linus' git master is that pretty much any change (timestamp, hardlinks) ends up > calling notify_change() which calls the fs-specific one, and in > the verity case basically denies everything, right? That's not correct. The verity case only denies truncate, because changing the data of the file would break the Merkle tree checksums. The metadata of the file is is not made immutable. So a verity-protected file can be deleted, renamed, can have hard links, and the timestamps can be set via utimes(), etc. Cheers, - Ted