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=-11.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS 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 C9942C56201 for ; Tue, 24 Nov 2020 23:28:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 834FD2137B for ; Tue, 24 Nov 2020 23:28:18 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="xe5/qIrg" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388575AbgKXX2R (ORCPT ); Tue, 24 Nov 2020 18:28:17 -0500 Received: from mail.kernel.org ([198.145.29.99]:37914 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388499AbgKXX2R (ORCPT ); Tue, 24 Nov 2020 18:28:17 -0500 Received: from sol.localdomain (172-10-235-113.lightspeed.sntcca.sbcglobal.net [172.10.235.113]) (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 213DF2100A; Tue, 24 Nov 2020 23:28:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1606260496; bh=Oo4Tlzm+6V2f+cAlPJ1FnNFARv4c7gmBZzibGJ+KTPA=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=xe5/qIrgFn//Ktx8T3FzD8iH+OmarHXR72XJec5aY3dKU9ct5j77kLudzv2sZf5oJ OGLz2xon5t1SKARHH1Shpa+fH+vE/ro2Dxh4IgiIiXhu9GMsszm9Js/C2MAv2yO0kf +eIj3mO0kFqZH0y5k2Aj81/VXm+rLTLYJc0plIV0= Date: Tue, 24 Nov 2020 15:28:14 -0800 From: Eric Biggers To: linux-fscrypt@vger.kernel.org Cc: linux-ext4@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, linux-mtd@lists.infradead.org, linux-fsdevel@vger.kernel.org Subject: Re: [PATCH 0/5] fscrypt: prevent creating duplicate encrypted filenames Message-ID: References: <20201118075609.120337-1-ebiggers@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201118075609.120337-1-ebiggers@kernel.org> Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org On Tue, Nov 17, 2020 at 11:56:04PM -0800, Eric Biggers wrote: > This series fixes a longstanding race condition where a duplicate > filename can be created in an encrypted directory if a syscall that > creates a new filename (e.g. open() or mkdir()) races with the > directory's encryption key being added. > > To close this race, we need to prevent creating files if the dentry is > still marked as a no-key name. I.e. we need to fail the ->create() (or > other operation that creates a new filename) if the key wasn't available > when doing the dentry lookup earlier in the syscall, even if the key was > concurrently added between the dentry lookup and ->create(). > > See patch 1 for a more detailed explanation. > > Patch 1 introduces a helper function required for the fix. Patches 2-4 > fix the bug on ext4, f2fs, and ubifs. Patch 5 is a cleanup. > > This fixes xfstest generic/595 on ubifs, but that test was hitting this > bug only accidentally. I've also written a new xfstest which reproduces > this bug on both ext4 and ubifs. > > Eric Biggers (5): > fscrypt: add fscrypt_is_nokey_name() > ext4: prevent creating duplicate encrypted filenames > f2fs: prevent creating duplicate encrypted filenames > ubifs: prevent creating duplicate encrypted filenames > fscrypt: remove unnecessary calls to fscrypt_require_key() > > fs/crypto/hooks.c | 31 +++++++++++-------------------- > fs/ext4/namei.c | 3 +++ > fs/f2fs/f2fs.h | 2 ++ > fs/ubifs/dir.c | 17 +++++++++++++---- > include/linux/fscrypt.h | 37 +++++++++++++++++++++++++++++++++++-- > 5 files changed, 64 insertions(+), 26 deletions(-) > > > base-commit: 3ceb6543e9cf6ed87cc1fbc6f23ca2db903564cd All applied to fscrypt.git#master for 5.11. I'd still appreciate acks for ext4, f2fs, and ubifs though. - Eric