From patchwork Thu Mar 16 18:14:10 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Luis Henriques X-Patchwork-Id: 13178177 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 09FB7C6FD1F for ; Thu, 16 Mar 2023 18:14:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230140AbjCPSOW (ORCPT ); Thu, 16 Mar 2023 14:14:22 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36374 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229621AbjCPSOV (ORCPT ); Thu, 16 Mar 2023 14:14:21 -0400 Received: from smtp-out1.suse.de (smtp-out1.suse.de [195.135.220.28]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 52D8D3C29; Thu, 16 Mar 2023 11:14:20 -0700 (PDT) Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id B984021A3B; Thu, 16 Mar 2023 18:14:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1678990458; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=wPYxUl/V0E0fQjPzR03hgTUP8YMge8ZIO2XP7gX1C3s=; b=S6Cs9pO/cWfbFKvIjeuhYXDHc+oVPLHQVLSFtRwJGAXesXJBfftVsm6nHeA/uCRhuTPQK4 Kgx1W9qnKxmufPDz1+3LpF4AAg2CS0nuO6OnFcDAEJbkpcWlMVThVPg0+b1yoLkJHk5wTr 5i5hUQigWt43VgmNVR+dYg+zTKYkGXQ= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1678990458; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=wPYxUl/V0E0fQjPzR03hgTUP8YMge8ZIO2XP7gX1C3s=; b=ylKYUdoHK6tYD29ZZc7kL6KnlL1I54rv2q+e0f/LpOy42rFxpHgCT5eR7QAjXMZ+Ax61sL ovSqcNwIHtqn/TBw== Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id 1D18C133E0; Thu, 16 Mar 2023 18:14:18 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id SSvEA3pcE2RtXAAAMHmgww (envelope-from ); Thu, 16 Mar 2023 18:14:18 +0000 Received: from localhost (brahms.olymp [local]) by brahms.olymp (OpenSMTPD) with ESMTPA id 36427925; Thu, 16 Mar 2023 18:14:14 +0000 (UTC) From: =?utf-8?q?Lu=C3=ADs_Henriques?= To: Eric Biggers , Xiubo Li , Jeff Layton Cc: "Theodore Y. Ts'o" , Jaegeuk Kim , Ilya Dryomov , linux-fscrypt@vger.kernel.org, ceph-devel@vger.kernel.org, linux-kernel@vger.kernel.org, =?utf-8?q?Lu?= =?utf-8?q?=C3=ADs_Henriques?= Subject: [PATCH v3 0/3] ceph: fscrypt: fix atomic open bug for encrypted directories Date: Thu, 16 Mar 2023 18:14:10 +0000 Message-Id: <20230316181413.26916-1-lhenriques@suse.de> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fscrypt@vger.kernel.org Hi! I started seeing fstest generic/123 failing in ceph fscrypt, when running it with 'test_dummy_encryption'. This test is quite simple: 1. Creates a directory with write permissions for root only 2. Writes into a file in that directory 3. Uses 'su' to try to modify that file as a different user, and gets -EPERM All the test steps succeed, but the test fails to cleanup: 'rm -rf ' will fail with -ENOTEMPTY. 'strace' shows that calling unlinkat() to remove the file got a -ENOENT and then -ENOTEMPTY for the directory. This is because 'su' does a drop_caches ('su (874): drop_caches: 2' in dmesg), and ceph's atomic open will do: if (IS_ENCRYPTED(dir)) { set_bit(CEPH_MDS_R_FSCRYPT_FILE, &req->r_req_flags); if (!fscrypt_has_encryption_key(dir)) { spin_lock(&dentry->d_lock); dentry->d_flags |= DCACHE_NOKEY_NAME; spin_unlock(&dentry->d_lock); } } Although 'dir' has the encryption key available, fscrypt_has_encryption_key() will return 'false' because fscrypt info isn't yet set after the cache cleanup. The first patch will add a new helper for the atomic_open that will force the fscrypt info to be loaded into an inode that has been evicted recently but for which the key is still available. The second patch switches ceph atomic_open to use the new fscrypt helper. Cheers, Tested-by: Xiubo Li and Reviewed-by: Xiubo Li --- Luís Changes since v2: - Make helper more generic and to be used both in lookup and atomic open operations - Modify ceph_lookup (patch 0002) and ceph_atomic_open (patch 0003) to use the new helper Changes since v1: - Dropped IS_ENCRYPTED() from helper function because kerneldoc says already that it applies to encrypted directories and, most importantly, because it would introduce a different behaviour for CONFIG_FS_ENCRYPTION and !CONFIG_FS_ENCRYPTION. - Rephrased helper kerneldoc Changes since initial RFC (after Eric's review): - Added kerneldoc comments to the new fscrypt helper - Dropped '__' from helper name (now fscrypt_prepare_atomic_open()) - Added IS_ENCRYPTED() check in helper - DCACHE_NOKEY_NAME is not set if fscrypt_get_encryption_info() returns an error - Fixed helper for !CONFIG_FS_ENCRYPTION (now defined 'static inline') Luís Henriques (3): fscrypt: new helper function - fscrypt_prepare_lookup_partial() ceph: switch ceph_open() to use new fscrypt helper ceph: switch ceph_open_atomic() to use the new fscrypt helper fs/ceph/dir.c | 13 +++++++------ fs/ceph/file.c | 8 +++----- fs/crypto/hooks.c | 37 +++++++++++++++++++++++++++++++++++++ include/linux/fscrypt.h | 7 +++++++ 4 files changed, 54 insertions(+), 11 deletions(-)