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=-2.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_PASS,T_DKIMWL_WL_HIGH,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 EDE81C433F4 for ; Sun, 26 Aug 2018 17:04:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9F1DA208DB for ; Sun, 26 Aug 2018 17:04:39 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="YKO/eJeb" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9F1DA208DB Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org 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 S1726949AbeHZUrn (ORCPT ); Sun, 26 Aug 2018 16:47:43 -0400 Received: from mail.kernel.org ([198.145.29.99]:33958 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726714AbeHZUrm (ORCPT ); Sun, 26 Aug 2018 16:47:42 -0400 Received: from sol.localdomain (c-67-185-97-198.hsd1.wa.comcast.net [67.185.97.198]) (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 32FFD208C1; Sun, 26 Aug 2018 17:04:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1535303076; bh=ohaZbZAB95OjMvy7U3GOyZwt2LQUz230ySU1sSUuS6k=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=YKO/eJebcKyjtkaEnYRW+KGAwoHJC+HtU56EmGM0fagRT8D186na3vA2xa+XvLaR4 UWtUnK1ihI5Ls4gS+XSKfYaOgsR/XXOLj94Iwu9AiokLVvD24lNKyf//aRwWR24lR2 Bpr/GuK13K/i6VdnHAyhWzlVd5DC1GiW9vordyUE= Date: Sun, 26 Aug 2018 10:04:34 -0700 From: Eric Biggers To: Chuck Lever Cc: 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 02/10] fs-verity: add data verification hooks for ->readpages() Message-ID: <20180826170433.GA728@sol.localdomain> References: <20180824161642.1144-1-ebiggers@kernel.org> <20180824161642.1144-3-ebiggers@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Chuck, On Sun, Aug 26, 2018 at 11:55:57AM -0400, Chuck Lever wrote: > > + > > +/** > > + * fsverity_verify_page - verify a data page > > + * > > + * Verify a page that has just been read from a file against that file's Merkle > > + * tree. The page is assumed to be a pagecache page. > > + * > > + * Return: true if the page is valid, else false. > > + */ > > +bool fsverity_verify_page(struct page *data_page) > > +{ > > + struct inode *inode = data_page->mapping->host; > > + const struct fsverity_info *vi = get_fsverity_info(inode); > > + struct ahash_request *req; > > + bool valid; > > + > > + req = ahash_request_alloc(vi->hash_alg->tfm, GFP_KERNEL); > > + if (unlikely(!req)) > > + return false; > > + > > + valid = verify_page(inode, vi, req, data_page); > > + > > + ahash_request_free(req); > > + > > + return valid; > > +} > > +EXPORT_SYMBOL_GPL(fsverity_verify_page); > > + > > +/** > > + * fsverity_verify_bio - verify a 'read' bio that has just completed > > + * > > + * Verify a set of pages that have just been read from a file against that > > + * file's Merkle tree. The pages are assumed to be pagecache pages. Pages that > > + * fail verification are set to the Error state. Verification is skipped for > > + * pages already in the Error state, e.g. due to fscrypt decryption failure. > > + */ > > +void fsverity_verify_bio(struct bio *bio) > > Hi Eric- > > This kind of API won't work for remote filesystems, which do not use > "struct bio" to do their I/O. Could a remote filesystem solely use > fsverity_verify_page instead? > Yes, filesystems don't have to use fsverity_verify_bio(). They can call fsverity_verify_page() on each page instead. I will clarify this in the next revision of the patchset. - Eric