From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Theodore Ts'o" Subject: Re: [PATCH 4/4] ubifs: Implement new mount option, fscrypt_key_required Date: Thu, 14 Mar 2019 19:07:02 -0400 Message-ID: <20190314230702.GE6482@mit.edu> References: <20190314171559.27584-5-richard@nod.at> <20190314174913.GA30026@gmail.com> <1957441.Hty6t2mpXG@blindfold> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <1957441.Hty6t2mpXG@blindfold> Sender: linux-kernel-owner@vger.kernel.org To: Richard Weinberger Cc: Eric Biggers , linux-mtd@lists.infradead.org, linux-fscrypt@vger.kernel.org, jaegeuk@kernel.org, linux-unionfs@vger.kernel.org, miklos@szeredi.hu, amir73il@gmail.com, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, paullawrence@google.com List-Id: linux-unionfs@vger.kernel.org Richard --- stepping back for a moment, in your use case, are you assuming that the encryption key is always going to be present while the system is running? Ubifs can't use dm-crypt, since it doesn't have a block device, but if you could, is much more like dm-crypt, in that you have the key *before* the file system is mounted, and you don't really expect the key to ever be expunged from the system while it is mounted? If that's true, maybe the real mismatch is in using fscrypt in the first place --- and in fact, something where you encrypt everything, including the file system metadata (ala dm-crypt), would actually give you much better security properties. - Ted