From patchwork Sat Oct 31 22:05:51 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Eric Biggers X-Patchwork-Id: 1391672 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org (client-ip=23.128.96.18; helo=vger.kernel.org; envelope-from=linux-ext4-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=pass (p=none dis=none) header.from=kernel.org Authentication-Results: ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=default header.b=tHNjyLqY; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by ozlabs.org (Postfix) with ESMTP id 4CNtdg135kz9sRR for ; Sun, 1 Nov 2020 09:09:59 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726063AbgJaWJ5 (ORCPT ); Sat, 31 Oct 2020 18:09:57 -0400 Received: from mail.kernel.org ([198.145.29.99]:39750 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725972AbgJaWJy (ORCPT ); Sat, 31 Oct 2020 18:09:54 -0400 Received: from sol.attlocal.net (172-10-235-113.lightspeed.sntcca.sbcglobal.net [172.10.235.113]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 7479D2076D; Sat, 31 Oct 2020 22:09:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1604182193; bh=mU4u4OeBiyB0ajGFtgXeUtVhy39lvr5DXQg14RZoQVM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=tHNjyLqYTwSXhVsJ1eW6WsK8fMTy/PMcW0EWoU2wlHm20ApQrIeE84yGxvMeExIb+ FADZJdS5CtvF9EgYkt00zoFxOTLxR3ArG0krL6ujh73zsq+v3Xtt3tyiR95YD21kib WMQIkNpEBHW8ustesBzYUh5Q0PIpHx9WW669HT/0= From: Eric Biggers To: stable@vger.kernel.org Cc: linux-fscrypt@vger.kernel.org, linux-ext4@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, linux-mtd@lists.infradead.org, Sarthak Kukreti , Theodore Ts'o Subject: [PATCH 4.19 3/5] fs, fscrypt: clear DCACHE_ENCRYPTED_NAME when unaliasing directory Date: Sat, 31 Oct 2020 15:05:51 -0700 Message-Id: <20201031220553.1085782-4-ebiggers@kernel.org> X-Mailer: git-send-email 2.29.1 In-Reply-To: <20201031220553.1085782-1-ebiggers@kernel.org> References: <20201031220553.1085782-1-ebiggers@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org From: Eric Biggers commit 0bf3d5c1604ecbbd4e49e9f5b3c79152b87adb0d upstream. Make __d_move() clear DCACHE_ENCRYPTED_NAME on the source dentry. This is needed for when d_splice_alias() moves a directory's encrypted alias to its decrypted alias as a result of the encryption key being added. Otherwise, the decrypted alias will incorrectly be invalidated on the next lookup, causing problems such as unmounting a mount the user just mount()ed there. Note that we don't have to support arbitrary moves of this flag because fscrypt doesn't allow dentries with DCACHE_ENCRYPTED_NAME to be the source or target of a rename(). Fixes: 28b4c263961c ("ext4 crypto: revalidate dentry after adding or removing the key") Reported-by: Sarthak Kukreti Signed-off-by: Eric Biggers Signed-off-by: Theodore Ts'o --- fs/dcache.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff --git a/fs/dcache.c b/fs/dcache.c index 20370a0997bf9..1897833a46685 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -2712,6 +2712,20 @@ static void copy_name(struct dentry *dentry, struct dentry *target) call_rcu(&old_name->u.head, __d_free_external_name); } +/* + * When d_splice_alias() moves a directory's encrypted alias to its decrypted + * alias as a result of the encryption key being added, DCACHE_ENCRYPTED_NAME + * must be cleared. Note that we don't have to support arbitrary moves of this + * flag because fscrypt doesn't allow encrypted aliases to be the source or + * target of a rename(). + */ +static inline void fscrypt_handle_d_move(struct dentry *dentry) +{ +#if IS_ENABLED(CONFIG_FS_ENCRYPTION) + dentry->d_flags &= ~DCACHE_ENCRYPTED_NAME; +#endif +} + /* * __d_move - move a dentry * @dentry: entry to move @@ -2787,6 +2801,7 @@ static void __d_move(struct dentry *dentry, struct dentry *target, list_move(&dentry->d_child, &dentry->d_parent->d_subdirs); __d_rehash(dentry); fsnotify_update_flags(dentry); + fscrypt_handle_d_move(dentry); write_seqcount_end(&target->d_seq); write_seqcount_end(&dentry->d_seq);