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=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT 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 C8776C46470 for ; Tue, 7 Aug 2018 07:37:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7C3EB2177A for ; Tue, 7 Aug 2018 07:37:19 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7C3EB2177A Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388893AbeHGJuU (ORCPT ); Tue, 7 Aug 2018 05:50:20 -0400 Received: from mga01.intel.com ([192.55.52.88]:3687 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732805AbeHGJuU (ORCPT ); Tue, 7 Aug 2018 05:50:20 -0400 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from orsmga005.jf.intel.com ([10.7.209.41]) by fmsmga101.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 07 Aug 2018 00:37:16 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.51,454,1526367600"; d="scan'208";a="246785540" Received: from chenyu-desktop.sh.intel.com (HELO chenyu-desktop) ([10.239.160.116]) by orsmga005.jf.intel.com with ESMTP; 07 Aug 2018 00:36:57 -0700 Date: Tue, 7 Aug 2018 15:43:12 +0800 From: Yu Chen To: joeyli Cc: Pavel Machek , Ryan Chen , oneukum@suse.com, "Rafael J. Wysocki" , ebiggers@google.com, Theodore Ts'o , smueller@chronox.de, denkenz@gmail.com, Linux PM list , linux-crypto@vger.kernel.org, Linux Kernel Mailing List , kookoo.gu@intel.com, Zhang Rui Subject: Re: [PATCH 0/4][RFC v2] Introduce the in-kernel hibernation encryption Message-ID: <20180807074312.GB17894@chenyu-desktop> References: <20180723162302.GA4503@sandybridge-desktop> <1532590246.7411.3.camel@suse.com> <20180726081404.GG4244@linux-l9pv.suse> <20180730170415.GQ4244@linux-l9pv.suse> <20180803033702.GB416@sandybridge-desktop> <20180803053445.GC4244@linux-l9pv.suse> <20180805100200.GB22948@amd> <20180806084534.GB12124@chenyu-desktop> <20180806103958.GI27062@linux-l9pv.suse> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180806103958.GI27062@linux-l9pv.suse> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Aug 06, 2018 at 06:39:58PM +0800, joeyli wrote: > On Mon, Aug 06, 2018 at 04:45:34PM +0800, Yu Chen wrote: > > Hi Pavel, > > On Sun, Aug 05, 2018 at 12:02:00PM +0200, Pavel Machek wrote: > > > Hi! > > > > > > > > User space doesn't need to involve. The EFI root key is generated by > > > > > EFI boot stub and be transfer to kernel. It's stored in EFI boot service > > > > > variable that it can only be accessed by trusted EFI binary when > > > > > secure boot is enabled. > > > > > > > > > Okay, this apply to the 'suspend' phase, right? > > > > I'm still a little confused about the 'resume' phase. > > > > Taking encryption as example(not signature), > > > > the purpose of doing hibernation encryption is to prevent other users > > > > from stealing ram content. Say, user A uses a passphrase to generate the > > > > > > No, I don't think that's purpose here. > > > > > > Purpose here is to prevent user from reading/modifying kernel memory > > > content on machine he owns. > > > > > Say, A puts his laptop into hibernation and walks away, > > and B walks by, and opens A's laptop and wakes up the system and he > > can do what he wants. Although EFI key/TPM trusted key is enabled, > > currently there's no certification during resume, which sounds > > unsafe to me. Afterall, the original requirement is to probe > > user for password during resume, which sounds more natural. > > OK, I saw your case. This is a physical accessing. > > I have a question: The suspend to memory also has the same behavior > and more people are using suspend. Should we think a common solution > to cover S3 and S4? > Since STD behaves more likely a boot up, STR does not have solid requirement for certification. > > > Strange as it may sound, that is what "secure" boot requires (and what > > > Disney wants). > > > > > Ok, I understand this requirement, and I'm also concerning how to > > distinguish different users from seeing data of each other. > > > > Joey, > > I'm thinking of a possible direction which could take advantage > > of the password. It leverages either EFI key or TPM > > trusted key to get it done. Does it make sense? > > > > 1. The user space generates a symetric key key_user using > > the password, and passes the key_user to the kernel as the master > > key. > > 2. The kernel uses the EFI key or TPM trusted key to encrypt > > the key_user thus gets a encrypt_key. > > 3. Uses the encrypt_key to do snapshot encryption > > 4. During resume, the same encrypt_key is generated following > > the same steps(I assume the same EFI key or TPM key could be fetched > > during resumed, right?) and do the snapshot decryption. > > > > Yes, we can use TPM key to protect the user key. But I suggest that we > should give user a function to disable the user key because not everyone > want to key-in a password for hibernate/resume and also snapshot image > encryption. > > Two policies: > - When user key-in user key, the snapshot image must be encryption. > - Without key-in user key, I still want the snapshot image can be encryption. > > No matter that the user key be key-in or not, the snapshot image must be > encrypted by a kernel key. So I suggest that we treat the user key as a salt > for snapshot image encryption and authentication. If the user key > be disabled, then kernel just generates a random number as a salt. > > Actually, the kernel must compares the user key before snapshot decryption. > If the user key doesn't match but user space still triggers furture resume > process. Then kernel direct drops the snapshot image. > Anyway I'm ok with using TPM for major 'security', please feel free to send a second version out, and for certification implementation we can have further discussion on that later. Best, Yu > > And this is what fscrypt is doing: > > Documentation/filesystems/fscrypt.rst > > > The use case is different. We have two key for two purposes. And the two > functions can be separated. > > Thanks > Joey Lee