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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_MUTT 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 20501C31E52 for ; Sat, 15 Jun 2019 15:08:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id F343D20866 for ; Sat, 15 Jun 2019 15:08:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726905AbfFOPIq (ORCPT ); Sat, 15 Jun 2019 11:08:46 -0400 Received: from outgoing-auth-1.mit.edu ([18.9.28.11]:57351 "EHLO outgoing.mit.edu" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725944AbfFOPIp (ORCPT ); Sat, 15 Jun 2019 11:08:45 -0400 Received: from callcc.thunk.org (rrcs-74-87-88-165.west.biz.rr.com [74.87.88.165]) (authenticated bits=0) (User authenticated as tytso@ATHENA.MIT.EDU) by outgoing.mit.edu (8.14.7/8.12.4) with ESMTP id x5FF8Lhv005865 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Sat, 15 Jun 2019 11:08:22 -0400 Received: by callcc.thunk.org (Postfix, from userid 15806) id 2BC23420484; Sat, 15 Jun 2019 11:08:21 -0400 (EDT) Date: Sat, 15 Jun 2019 11:08:21 -0400 From: "Theodore Ts'o" To: Eric Biggers Cc: linux-fscrypt@vger.kernel.org, linux-ext4@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, linux-fsdevel@vger.kernel.org, linux-api@vger.kernel.org, linux-integrity@vger.kernel.org, Jaegeuk Kim , Victor Hsieh , Dave Chinner , Christoph Hellwig , "Darrick J . Wong" , Linus Torvalds Subject: Re: [PATCH v4 10/16] fs-verity: implement FS_IOC_ENABLE_VERITY ioctl Message-ID: <20190615150821.GK6142@mit.edu> References: <20190606155205.2872-1-ebiggers@kernel.org> <20190606155205.2872-11-ebiggers@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190606155205.2872-11-ebiggers@kernel.org> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Thu, Jun 06, 2019 at 08:51:59AM -0700, Eric Biggers wrote: > From: Eric Biggers > > Add a function for filesystems to call to implement the > FS_IOC_ENABLE_VERITY ioctl. This ioctl enables fs-verity on a file. > > See the "FS_IOC_ENABLE_VERITY" section of > Documentation/filesystems/fsverity.rst for the documentation. > > Signed-off-by: Eric Biggers > diff --git a/fs/verity/enable.c b/fs/verity/enable.c > new file mode 100644 > index 000000000000..7e7ef9d3c376 > --- /dev/null > +++ b/fs/verity/enable.c > + /* Tell the filesystem to finish enabling verity on the file */ > + err = vops->end_enable_verity(filp, desc, desc_size, params.tree_size); > + if (err) { > + fsverity_err(inode, "%ps() failed with err %d", > + vops->end_enable_verity, err); > + fsverity_free_info(vi); > + } else { > + /* Successfully enabled verity */ > + > + WARN_ON(!IS_VERITY(inode)); > + > + /* > + * Readers can start using ->i_verity_info immediately, so it > + * can't be rolled back once set. So don't set it until just > + * after the filesystem has successfully enabled verity. > + */ > + fsverity_set_info(inode, vi); > + } If end_enable_Verity() retuns success, and IS_VERITY is not set, I would think that we should report the error via fsverity_err() and return an error to userspace, and *not* call fsverity_set_info(). I don't think the stack trace printed by WARN_ON is going to very interesting, since the call path which gets us to enable_verity() is not going to be surprising. > + > + if (inode->i_size <= 0) { > + err = -EINVAL; > + goto out_unlock; > + } How hard would it be to support fsverity for zero-length files? There would be no Merkle tree, but there still would be an fsverity header file on which we can calculate a checksum for the digital signature. - Ted