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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id EFE87C74A4B for ; Mon, 13 Mar 2023 12:33:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229777AbjCMMdU (ORCPT ); Mon, 13 Mar 2023 08:33:20 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58608 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229548AbjCMMdQ (ORCPT ); Mon, 13 Mar 2023 08:33:16 -0400 Received: from smtp-out1.suse.de (smtp-out1.suse.de [IPv6:2001:67c:2178:6::1c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id ABE2E19127; Mon, 13 Mar 2023 05:33:14 -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 B8C0B221B4; Mon, 13 Mar 2023 12:33:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1678710792; 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=clL6isl+kRCjub6IYvTubyA1KWdyBcpxsCA8BvRWS64=; b=ynBkq9Jc8ZU6ci4AMmAMpO7o7lEmrVkCTioOZonMHMN585uolQKWXy2I5ezqIB7JzxdsiJ B0Yl2nkA++fdIXIHRJF0lbT0aATCcwmdmH43aeTTeZSvFTUQvpRoQj0AL9QJk0TnD9BwFN dxLkQuQkJ2cP28zshfsWJtQuU07BdK8= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1678710792; 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=clL6isl+kRCjub6IYvTubyA1KWdyBcpxsCA8BvRWS64=; b=uI4rhJsoXCvpymp30cEwbeMxOeB6fdG+1djc7TIhhBV/dDqtkwGeAGsc6WbokJOYZaP0NK oQbvM4+wNobryuAg== 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 2331013582; Mon, 13 Mar 2023 12:33:12 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id UWyqBQgYD2RnCQAAMHmgww (envelope-from ); Mon, 13 Mar 2023 12:33:12 +0000 Received: from localhost (brahms.olymp [local]) by brahms.olymp (OpenSMTPD) with ESMTPA id 8f5c4974; Mon, 13 Mar 2023 12:33:11 +0000 (UTC) From: =?UTF-8?q?Lu=C3=ADs=20Henriques?= 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=C3=ADs=20Henriques?= Subject: [PATCH 0/2] ceph: fscrypt: fix atomic open bug for encrypted directories Date: Mon, 13 Mar 2023 12:33:08 +0000 Message-Id: <20230313123310.13040-1-lhenriques@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: ceph-devel@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 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 (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 | 35 +++++++++++++++++++++++++++++++++++ include/linux/fscrypt.h | 7 +++++++ 3 files changed, 45 insertions(+), 5 deletions(-)