From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:56747 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965731AbcIVRlZ (ORCPT ); Thu, 22 Sep 2016 13:41:25 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Eric Biggers , Theodore Tso , Jaegeuk Kim Subject: [PATCH 4.4 006/118] fscrypto: require write access to mount to set encryption policy Date: Thu, 22 Sep 2016 19:28:26 +0200 Message-Id: <20160922172938.953385875@linuxfoundation.org> In-Reply-To: <20160922172938.643879685@linuxfoundation.org> References: <20160922172938.643879685@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Biggers commit ba63f23d69a3a10e7e527a02702023da68ef8a6d upstream. Since setting an encryption policy requires writing metadata to the filesystem, it should be guarded by mnt_want_write/mnt_drop_write. Otherwise, a user could cause a write to a frozen or readonly filesystem. This was handled correctly by f2fs but not by ext4. Make fscrypt_process_policy() handle it rather than relying on the filesystem to get it right. Signed-off-by: Eric Biggers Cc: stable@vger.kernel.org # 4.1+; check fs/{ext4,f2fs} Signed-off-by: Theodore Ts'o Acked-by: Jaegeuk Kim Signed-off-by: Greg Kroah-Hartman --- fs/ext4/ioctl.c | 6 ++++++ 1 file changed, 6 insertions(+) --- a/fs/ext4/ioctl.c +++ b/fs/ext4/ioctl.c @@ -629,7 +629,13 @@ resizefs_out: goto encryption_policy_out; } + err = mnt_want_write_file(filp); + if (err) + goto encryption_policy_out; + err = ext4_process_policy(&policy, inode); + + mnt_drop_write_file(filp); encryption_policy_out: return err; #else