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 X-Spam-Level: X-Spam-Status: No, score=-5.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 429DAC31E40 for ; Tue, 13 Aug 2019 00:39:55 +0000 (UTC) Received: from lists.sourceforge.net (lists.sourceforge.net [216.105.38.7]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 0B242206A2; Tue, 13 Aug 2019 00:39:54 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=sourceforge.net header.i=@sourceforge.net header.b="RKmT/LqL"; dkim=fail reason="signature verification failed" (1024-bit key) header.d=sf.net header.i=@sf.net header.b="CPc9N3DC" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0B242206A2 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=mit.edu Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linux-f2fs-devel-bounces@lists.sourceforge.net Received: from [127.0.0.1] (helo=sfs-ml-2.v29.lw.sourceforge.com) by sfs-ml-2.v29.lw.sourceforge.com with esmtp (Exim 4.90_1) (envelope-from ) id 1hxKqw-00055m-Li; Tue, 13 Aug 2019 00:39:54 +0000 Received: from [172.30.20.202] (helo=mx.sourceforge.net) by sfs-ml-2.v29.lw.sourceforge.com with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.90_1) (envelope-from ) id 1hxKqv-00055a-Rs for linux-f2fs-devel@lists.sourceforge.net; Tue, 13 Aug 2019 00:39:53 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=sourceforge.net; s=x; h=In-Reply-To:Content-Type:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To:Content-Transfer-Encoding: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=8Nj8gcAdAyF2PrqbSBR9mjod/iUGSBR3MkMGJVHtkSU=; b=RKmT/LqLUaxN7J4Z0oasHwxgCt QaySiGgjmdFd+k/PD3sokxqA/MOvvAXJ3ClDEpJOXb9hOtp/RyztKunBFAqN0BoIYoG563OYkAEiJ 1BeSHpFjKgnc4U7YzazPaLfKOeAvqrAr+0GWAyizCRFWZoYg+FonjKTBdDYxHbQnzXdE=; DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=sf.net; s=x ; h=In-Reply-To:Content-Type:MIME-Version:References:Message-ID:Subject:Cc:To :From:Date:Sender:Reply-To:Content-Transfer-Encoding:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=8Nj8gcAdAyF2PrqbSBR9mjod/iUGSBR3MkMGJVHtkSU=; b=CPc9N3DCMTJ4fVsrC2auWorOWB bhG+FhbsdMoLksUCklWryndu/mVAe6HhqB32+t0dvdEcJ+DzhVKgWhHnzj3lc3f7fRw//QGxUhxmZ Ok7aySyr+IJSpCB4vcAZ3R5r5dynlxWewDoHSKY6cRyizGlURMuBAmjVujnyE8qe+gsQ=; Received: from outgoing-auth-1.mit.edu ([18.9.28.11] helo=outgoing.mit.edu) by sfi-mx-3.v28.lw.sourceforge.com with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.90_1) id 1hxKqu-001nmJ-7e for linux-f2fs-devel@lists.sourceforge.net; Tue, 13 Aug 2019 00:39:53 +0000 Received: from callcc.thunk.org (guestnat-104-133-9-109.corp.google.com [104.133.9.109] (may be forged)) (authenticated bits=0) (User authenticated as tytso@ATHENA.MIT.EDU) by outgoing.mit.edu (8.14.7/8.12.4) with ESMTP id x7D0dcO9023746 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 12 Aug 2019 20:39:39 -0400 Received: by callcc.thunk.org (Postfix, from userid 15806) id B8C504218EF; Mon, 12 Aug 2019 20:39:37 -0400 (EDT) Date: Mon, 12 Aug 2019 20:39:37 -0400 From: "Theodore Y. Ts'o" To: Eric Biggers Message-ID: <20190813003937.GK28705@mit.edu> References: <20190805162521.90882-1-ebiggers@kernel.org> <20190805162521.90882-14-ebiggers@kernel.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20190805162521.90882-14-ebiggers@kernel.org> User-Agent: Mutt/1.10.1 (2018-07-13) X-Headers-End: 1hxKqu-001nmJ-7e Subject: Re: [f2fs-dev] [PATCH v8 13/20] fscrypt: v2 encryption policy support X-BeenThere: linux-f2fs-devel@lists.sourceforge.net X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Satya Tangirala , linux-api@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, linux-fscrypt@vger.kernel.org, keyrings@vger.kernel.org, linux-mtd@lists.infradead.org, linux-crypto@vger.kernel.org, linux-fsdevel@vger.kernel.org, Jaegeuk Kim , linux-ext4@vger.kernel.org, Paul Crowley Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: linux-f2fs-devel-bounces@lists.sourceforge.net On Mon, Aug 05, 2019 at 09:25:14AM -0700, Eric Biggers wrote: > From: Eric Biggers > > Add a new fscrypt policy version, "v2". It has the following changes > from the original policy version, which we call "v1" (*): > > - Master keys (the user-provided encryption keys) are only ever used as > input to HKDF-SHA512. This is more flexible and less error-prone, and > it avoids the quirks and limitations of the AES-128-ECB based KDF. > Three classes of cryptographically isolated subkeys are defined: > > - Per-file keys, like used in v1 policies except for the new KDF. > > - Per-mode keys. These implement the semantics of the DIRECT_KEY > flag, which for v1 policies made the master key be used directly. > These are also planned to be used for inline encryption when > support for it is added. > > - Key identifiers (see below). > > - Each master key is identified by a 16-byte master_key_identifier, > which is derived from the key itself using HKDF-SHA512. This prevents > users from associating the wrong key with an encrypted file or > directory. This was easily possible with v1 policies, which > identified the key by an arbitrary 8-byte master_key_descriptor. > > - The key must be provided in the filesystem-level keyring, not in a > process-subscribed keyring. > > The following UAPI additions are made: > > - The existing ioctl FS_IOC_SET_ENCRYPTION_POLICY can now be passed a > fscrypt_policy_v2 to set a v2 encryption policy. It's disambiguated > from fscrypt_policy/fscrypt_policy_v1 by the version code prefix. > > - A new ioctl FS_IOC_GET_ENCRYPTION_POLICY_EX is added. It allows > getting the v1 or v2 encryption policy of an encrypted file or > directory. The existing FS_IOC_GET_ENCRYPTION_POLICY ioctl could not > be used because it did not have a way for userspace to indicate which > policy structure is expected. The new ioctl includes a size field, so > it is extensible to future fscrypt policy versions. > > - The ioctls FS_IOC_ADD_ENCRYPTION_KEY, FS_IOC_REMOVE_ENCRYPTION_KEY, > and FS_IOC_GET_ENCRYPTION_KEY_STATUS now support managing keys for v2 > encryption policies. Such keys are kept logically separate from keys > for v1 encryption policies, and are identified by 'identifier' rather > than by 'descriptor'. The 'identifier' need not be provided when > adding a key, since the kernel will calculate it anyway. > > This patch temporarily keeps adding/removing v2 policy keys behind the > same permission check done for adding/removing v1 policy keys: > capable(CAP_SYS_ADMIN). However, the next patch will carefully take > advantage of the cryptographically secure master_key_identifier to allow > non-root users to add/remove v2 policy keys, thus providing a full > replacement for v1 policies. > > (*) Actually, in the API fscrypt_policy::version is 0 while on-disk > fscrypt_context::format is 1. But I believe it makes the most sense > to advance both to '2' to have them be in sync, and to consider the > numbering to start at 1 except for the API quirk. > > Signed-off-by: Eric Biggers Looks good, feel free to add: Reviewed-by: Theodore Ts'o _______________________________________________ Linux-f2fs-devel mailing list Linux-f2fs-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel