From patchwork Thu Mar 9 12:19:08 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Luis Henriques X-Patchwork-Id: 13167336 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 E8F11C61DA4 for ; Thu, 9 Mar 2023 12:19:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230143AbjCIMTS (ORCPT ); Thu, 9 Mar 2023 07:19:18 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33680 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229722AbjCIMTR (ORCPT ); Thu, 9 Mar 2023 07:19:17 -0500 Received: from smtp-out1.suse.de (smtp-out1.suse.de [IPv6:2001:67c:2178:6::1c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5268D1C7FC; Thu, 9 Mar 2023 04:19:16 -0800 (PST) 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 EB262219B9; Thu, 9 Mar 2023 12:19:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1678364354; 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=YtlE06MK38v4wUEGCfv9Lya1P+SBRtcUPdCKrIFmkWY=; b=QwhEfbgNYoa66mBXwPIK8+kmgDqlUpWJkv6ic6Gy6A7Rq9mKxoPQHH0y4k/0UxBPIHIQD0 t6jTVm0xwkpiQBSBAt4Nf4r9NC3dflMXxqe8ns4QsiAPFD/5PQwL9Rvvds/MVfplCxK6ih ihqL+OtK1toFylXVi5L7C8629S9aKvs= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1678364354; 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=YtlE06MK38v4wUEGCfv9Lya1P+SBRtcUPdCKrIFmkWY=; b=WIhze/eSN4I/rAvLyoYJrZuLC+wJtkXKfuRQSukyV+HhYD79jz9HhL9NvBqZqMXS717V9b UJHzZ04V1VSwo2Bw== 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 4D12913A10; Thu, 9 Mar 2023 12:19:14 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id V2WpD8LOCWSqbAAAMHmgww (envelope-from ); Thu, 09 Mar 2023 12:19:14 +0000 Received: from localhost (brahms.olymp [local]) by brahms.olymp (OpenSMTPD) with ESMTPA id a07c9311; Thu, 9 Mar 2023 12:19:13 +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: [RFC PATCH 0/2] ceph: fscrypt: fix atomic open bug for encrypted directories Date: Thu, 9 Mar 2023 12:19:08 +0000 Message-Id: <20230309121910.18939-1-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, --- Luís Henriques Luís Henriques (2): fscrypt: new helper function - __fscrypt_prepare_atomic_open() ceph: switch atomic open to use new fscrypt helper fs/ceph/file.c | 8 +++----- fs/crypto/hooks.c | 14 ++++++++++++++ include/linux/fscrypt.h | 6 ++++++ 3 files changed, 23 insertions(+), 5 deletions(-)