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=-8.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,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 99948C43613 for ; Sat, 22 Jun 2019 22:29:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6CBF22073F for ; Sat, 22 Jun 2019 22:29:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1561242541; bh=c8fVFZZuYkZhgy8reLNIA8g+E5ers06eeDGckiaZq3E=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=dyeu0RGB3Zwrt7v6j0/1FxSMcsnOGuAxl5PIpGRjj9/ipIMqueuXLiJmyt/1AS9lZ fWPPfn4ttB2+6tVTWwVIx2fpnMcBiX6mkH0R8tyLW4Y0O2Js+U7Qm++Rabq/QzBVvv uZ2rhOrRqRW05C8Zp7OMG65OEpjsSd1q/S/1Oa+8= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726437AbfFVW3B (ORCPT ); Sat, 22 Jun 2019 18:29:01 -0400 Received: from mail.kernel.org ([198.145.29.99]:49000 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725844AbfFVW3A (ORCPT ); Sat, 22 Jun 2019 18:29:00 -0400 Received: from localhost (unknown [104.132.1.68]) (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 45A6E206B7; Sat, 22 Jun 2019 22:28:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1561242539; bh=c8fVFZZuYkZhgy8reLNIA8g+E5ers06eeDGckiaZq3E=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=AYXStsrVq/xuYzf7uWcwMuGUXLnWY2Lo7cZxbMQPrq04wyTcErdo9cKIrdtloCcw2 80jHKyEdHZqbsjLmjF+7FwM2ykvZmhCZOYDwBNbJX8w4Xl7uYNzfqNncqR8ZgEYcpU Nh1jzXQiG2CFGViyc0d8oXrh17vVK382gSxHhz+A= Date: Sat, 22 Jun 2019 15:28:58 -0700 From: Jaegeuk Kim 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, "Theodore Y . Ts'o" , Victor Hsieh , Chandan Rajendra , Dave Chinner , Christoph Hellwig , "Darrick J . Wong" , Linus Torvalds Subject: Re: [PATCH v5 08/16] fs-verity: add the hook for file ->setattr() Message-ID: <20190622222858.GH19686@jaegeuk-macbookpro.roam.corp.google.com> References: <20190620205043.64350-1-ebiggers@kernel.org> <20190620205043.64350-9-ebiggers@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190620205043.64350-9-ebiggers@kernel.org> User-Agent: Mutt/1.8.2 (2017-04-18) Sender: linux-integrity-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org On 06/20, Eric Biggers wrote: > From: Eric Biggers > > Add a function fsverity_prepare_setattr() which filesystems that support > fs-verity must call to deny truncates of verity files. > > Reviewed-by: Theodore Ts'o Reviewed-by: Jaegeuk Kim > Signed-off-by: Eric Biggers > --- > fs/verity/open.c | 21 +++++++++++++++++++++ > include/linux/fsverity.h | 7 +++++++ > 2 files changed, 28 insertions(+) > > diff --git a/fs/verity/open.c b/fs/verity/open.c > index 3a3bb27e23f5e3..21ae0ef254a695 100644 > --- a/fs/verity/open.c > +++ b/fs/verity/open.c > @@ -296,6 +296,27 @@ int fsverity_file_open(struct inode *inode, struct file *filp) > } > EXPORT_SYMBOL_GPL(fsverity_file_open); > > +/** > + * fsverity_prepare_setattr - prepare to change a verity inode's attributes > + * @dentry: dentry through which the inode is being changed > + * @attr: attributes to change > + * > + * Verity files are immutable, so deny truncates. This isn't covered by the > + * open-time check because sys_truncate() takes a path, not a file descriptor. > + * > + * Return: 0 on success, -errno on failure > + */ > +int fsverity_prepare_setattr(struct dentry *dentry, struct iattr *attr) > +{ > + if (IS_VERITY(d_inode(dentry)) && (attr->ia_valid & ATTR_SIZE)) { > + pr_debug("Denying truncate of verity file (ino %lu)\n", > + d_inode(dentry)->i_ino); > + return -EPERM; > + } > + return 0; > +} > +EXPORT_SYMBOL_GPL(fsverity_prepare_setattr); > + > /** > * fsverity_cleanup_inode - free the inode's verity info, if present > * > diff --git a/include/linux/fsverity.h b/include/linux/fsverity.h > index 1372c236c8770c..cbcc358d073652 100644 > --- a/include/linux/fsverity.h > +++ b/include/linux/fsverity.h > @@ -46,6 +46,7 @@ static inline struct fsverity_info *fsverity_get_info(const struct inode *inode) > /* open.c */ > > extern int fsverity_file_open(struct inode *inode, struct file *filp); > +extern int fsverity_prepare_setattr(struct dentry *dentry, struct iattr *attr); > extern void fsverity_cleanup_inode(struct inode *inode); > > #else /* !CONFIG_FS_VERITY */ > @@ -62,6 +63,12 @@ static inline int fsverity_file_open(struct inode *inode, struct file *filp) > return IS_VERITY(inode) ? -EOPNOTSUPP : 0; > } > > +static inline int fsverity_prepare_setattr(struct dentry *dentry, > + struct iattr *attr) > +{ > + return IS_VERITY(d_inode(dentry)) ? -EOPNOTSUPP : 0; > +} > + > static inline void fsverity_cleanup_inode(struct inode *inode) > { > } > -- > 2.22.0.410.gd8fdbe21b5-goog