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=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,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 79F21C43381 for ; Mon, 18 Mar 2019 21:25:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 474D32085A for ; Mon, 18 Mar 2019 21:25:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727000AbfCRVZ0 (ORCPT ); Mon, 18 Mar 2019 17:25:26 -0400 Received: from zeniv.linux.org.uk ([195.92.253.2]:54506 "EHLO ZenIV.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726773AbfCRVZ0 (ORCPT ); Mon, 18 Mar 2019 17:25:26 -0400 Received: from viro by ZenIV.linux.org.uk with local (Exim 4.92 #3 (Red Hat Linux)) id 1h5zl4-000597-7o; Mon, 18 Mar 2019 21:25:22 +0000 Date: Mon, 18 Mar 2019 21:25:22 +0000 From: Al Viro To: Eric Biggers Cc: linux-fscrypt@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, linux-mtd@lists.infradead.org, linux-unionfs@vger.kernel.org, Sarthak Kukreti , Gao Xiang Subject: Re: [PATCH 1/5] fscrypt: clean up and improve dentry revalidation Message-ID: <20190318212522.GI2217@ZenIV.linux.org.uk> References: <20190317200444.5967-1-ebiggers@kernel.org> <20190317200444.5967-2-ebiggers@kernel.org> <20190317203822.GH2217@ZenIV.linux.org.uk> <20190318202948.GD194307@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190318202948.GD194307@gmail.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-ext4-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org On Mon, Mar 18, 2019 at 01:29:49PM -0700, Eric Biggers wrote: > On Sun, Mar 17, 2019 at 08:38:22PM +0000, Al Viro wrote: > > On Sun, Mar 17, 2019 at 01:04:40PM -0700, Eric Biggers wrote: > > > + /* > > > + * Ciphertext name; valid if the directory's key is still unavailable. > > > + * > > > + * Note: since fscrypt forbids rename() on ciphertext names, it should > > > + * be safe to access ->d_parent directly here. > > > > No, it is not. Again, d_splice_alias() on buggered fs image picking a reference > > to your subdirectory when doing a lookup elsewhere. It can relocate the > > damn thing, without rename() being allowed for _anything_. > > You're talking about directory hard links, right? In case of corrupted fs image - yes; the same can happen if you have a network filesystem with subdirectory moved around on server at the same time, but there you'll need a lot more elaborate ->d_revalidate() anyway. Directory hardlinks are certainly not allowed; however, we need the kernel to survive when it runs into that kind of crap on disk... From mboxrd@z Thu Jan 1 00:00:00 1970 From: Al Viro Subject: Re: [PATCH 1/5] fscrypt: clean up and improve dentry revalidation Date: Mon, 18 Mar 2019 21:25:22 +0000 Message-ID: <20190318212522.GI2217@ZenIV.linux.org.uk> References: <20190317200444.5967-1-ebiggers@kernel.org> <20190317200444.5967-2-ebiggers@kernel.org> <20190317203822.GH2217@ZenIV.linux.org.uk> <20190318202948.GD194307@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from [172.30.20.202] (helo=mx.sourceforge.net) by sfs-ml-2.v29.lw.sourceforge.com with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.90_1) (envelope-from ) id 1h5zlH-00007y-7e for linux-f2fs-devel@lists.sourceforge.net; Mon, 18 Mar 2019 21:25:35 +0000 Received: from zeniv.linux.org.uk ([195.92.253.2]) by sfi-mx-4.v28.lw.sourceforge.com with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.90_1) id 1h5zlF-00BU5O-8Z for linux-f2fs-devel@lists.sourceforge.net; Mon, 18 Mar 2019 21:25:35 +0000 Content-Disposition: inline In-Reply-To: <20190318202948.GD194307@gmail.com> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: linux-f2fs-devel-bounces@lists.sourceforge.net To: Eric Biggers Cc: linux-unionfs@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, linux-fscrypt@vger.kernel.org, linux-mtd@lists.infradead.org, Sarthak Kukreti , linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org On Mon, Mar 18, 2019 at 01:29:49PM -0700, Eric Biggers wrote: > On Sun, Mar 17, 2019 at 08:38:22PM +0000, Al Viro wrote: > > On Sun, Mar 17, 2019 at 01:04:40PM -0700, Eric Biggers wrote: > > > + /* > > > + * Ciphertext name; valid if the directory's key is still unavailable. > > > + * > > > + * Note: since fscrypt forbids rename() on ciphertext names, it should > > > + * be safe to access ->d_parent directly here. > > > > No, it is not. Again, d_splice_alias() on buggered fs image picking a reference > > to your subdirectory when doing a lookup elsewhere. It can relocate the > > damn thing, without rename() being allowed for _anything_. > > You're talking about directory hard links, right? In case of corrupted fs image - yes; the same can happen if you have a network filesystem with subdirectory moved around on server at the same time, but there you'll need a lot more elaborate ->d_revalidate() anyway. Directory hardlinks are certainly not allowed; however, we need the kernel to survive when it runs into that kind of crap on disk... 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=-2.5 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,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 B459AC43381 for ; Mon, 18 Mar 2019 21:27:38 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 76A40213F2 for ; Mon, 18 Mar 2019 21:27:38 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="uV4aTSmI" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 76A40213F2 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=zeniv.linux.org.uk Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-mtd-bounces+linux-mtd=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=4ZfpWNUIjL5HoWfiniEeMKZGUWxqxV9jVKhSimnEobk=; b=uV4aTSmIdlTdrf i0KUSUtGt1B2EdioKrpBxzsr4dcT9DfhVnIY+gDXqUn1Bcz6ZptaYEG4y3F2e5agXoEg06mx/kTKY 3JVxRCRiANJGa1AFqMvvGZcqMkJPQ1yczbnCHAo2ahFOVFgZbV+DdMxGGWrvme/1h4oNvdP54ZmI5 Iu0PHjcvJ3Gm3l3nGfPmlx3XFIJjOuoyeBgRP2L3OiCATKW9rY8amPU+tfQu6KiRV6EHQwSf5hdc5 WHSw38NtXabWM3LZHeMeVPuISxsxrUhi7qIjoX8IUks+6LfBPubv9Wyb3cPIs0cnz+nInAREXmCkK P6pEo5b3GwVN9GXMjGsw==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1h5znE-0003fl-Dj; Mon, 18 Mar 2019 21:27:36 +0000 Received: from zeniv.linux.org.uk ([195.92.253.2]) by bombadil.infradead.org with esmtps (Exim 4.90_1 #2 (Red Hat Linux)) id 1h5znA-0003bs-Ro for linux-mtd@lists.infradead.org; Mon, 18 Mar 2019 21:27:34 +0000 Received: from viro by ZenIV.linux.org.uk with local (Exim 4.92 #3 (Red Hat Linux)) id 1h5zl4-000597-7o; Mon, 18 Mar 2019 21:25:22 +0000 Date: Mon, 18 Mar 2019 21:25:22 +0000 From: Al Viro To: Eric Biggers Subject: Re: [PATCH 1/5] fscrypt: clean up and improve dentry revalidation Message-ID: <20190318212522.GI2217@ZenIV.linux.org.uk> References: <20190317200444.5967-1-ebiggers@kernel.org> <20190317200444.5967-2-ebiggers@kernel.org> <20190317203822.GH2217@ZenIV.linux.org.uk> <20190318202948.GD194307@gmail.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20190318202948.GD194307@gmail.com> User-Agent: Mutt/1.10.1 (2018-07-13) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190318_142732_900551_E5BD422A X-CRM114-Status: GOOD ( 10.54 ) X-BeenThere: linux-mtd@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Gao Xiang , linux-unionfs@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, linux-fscrypt@vger.kernel.org, linux-mtd@lists.infradead.org, Sarthak Kukreti , linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-mtd" Errors-To: linux-mtd-bounces+linux-mtd=archiver.kernel.org@lists.infradead.org On Mon, Mar 18, 2019 at 01:29:49PM -0700, Eric Biggers wrote: > On Sun, Mar 17, 2019 at 08:38:22PM +0000, Al Viro wrote: > > On Sun, Mar 17, 2019 at 01:04:40PM -0700, Eric Biggers wrote: > > > + /* > > > + * Ciphertext name; valid if the directory's key is still unavailable. > > > + * > > > + * Note: since fscrypt forbids rename() on ciphertext names, it should > > > + * be safe to access ->d_parent directly here. > > > > No, it is not. Again, d_splice_alias() on buggered fs image picking a reference > > to your subdirectory when doing a lookup elsewhere. It can relocate the > > damn thing, without rename() being allowed for _anything_. > > You're talking about directory hard links, right? In case of corrupted fs image - yes; the same can happen if you have a network filesystem with subdirectory moved around on server at the same time, but there you'll need a lot more elaborate ->d_revalidate() anyway. Directory hardlinks are certainly not allowed; however, we need the kernel to survive when it runs into that kind of crap on disk... ______________________________________________________ Linux MTD discussion mailing list http://lists.infradead.org/mailman/listinfo/linux-mtd/