From: joeyli <jlee@suse.com>
To: Yu Chen <yu.c.chen@intel.com>
Cc: Pavel Machek <pavel@ucw.cz>, Ryan Chen <yu.chen.surf@gmail.com>,
oneukum@suse.com,
"Rafael J. Wysocki" <rafael.j.wysocki@intel.com>,
ebiggers@google.com, Theodore Ts'o <tytso@mit.edu>,
smueller@chronox.de, denkenz@gmail.com,
Linux PM list <linux-pm@vger.kernel.org>,
linux-crypto@vger.kernel.org,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
kookoo.gu@intel.com, Zhang Rui <rui.zhang@intel.com>
Subject: Re: [PATCH 0/4][RFC v2] Introduce the in-kernel hibernation encryption
Date: Wed, 8 Aug 2018 00:27:46 +0800 [thread overview]
Message-ID: <20180807162746.GJ19234@linux-l9pv.suse> (raw)
In-Reply-To: <20180807074312.GB17894@chenyu-desktop>
On Tue, Aug 07, 2018 at 03:43:12PM +0800, Yu Chen wrote:
> 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.
In your A/B user case, when STR, B user can still open A's laptop
and wakes up the system and do what he wants because he can get
the console like resume from STD. I didn't see difference.
> > > > 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.
>
Regards
Joey Lee
next prev parent reply other threads:[~2018-08-07 16:28 UTC|newest]
Thread overview: 53+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-18 16:38 [PATCH 0/4][RFC v2] Introduce the in-kernel hibernation encryption Chen Yu
2018-07-18 16:39 ` [PATCH 1/4][RFC v2] PM / Hibernate: Add helper functions for " Chen Yu
2018-07-18 16:39 ` [PATCH 2/4][RFC v2] PM / hibernate: Install crypto hooks " Chen Yu
2018-07-18 16:40 ` [PATCH 4/4][RFC v2] tools: create power/crypto utility Chen Yu
2018-07-18 20:22 ` [PATCH 0/4][RFC v2] Introduce the in-kernel hibernation encryption Pavel Machek
2018-07-18 23:58 ` Yu Chen
2018-07-19 11:01 ` Pavel Machek
2018-07-19 13:20 ` Yu Chen
2018-07-20 10:25 ` Pavel Machek
2018-07-23 11:42 ` Oliver Neukum
2018-07-23 12:22 ` Pavel Machek
2018-07-23 16:38 ` Yu Chen
2018-07-24 12:05 ` Pavel Machek
2018-07-24 11:49 ` Oliver Neukum
2018-07-24 13:04 ` Pavel Machek
2018-07-23 16:23 ` Yu Chen
2018-07-24 11:40 ` Oliver Neukum
2018-07-24 12:01 ` Pavel Machek
2018-07-24 12:47 ` Oliver Neukum
2018-07-24 13:03 ` Pavel Machek
2018-07-24 13:01 ` Oliver Neukum
2018-07-26 7:30 ` Oliver Neukum
2018-07-26 8:14 ` joeyli
2018-07-30 17:04 ` joeyli
2018-08-03 3:37 ` Yu Chen
2018-08-03 5:34 ` joeyli
2018-08-03 13:14 ` Ryan Chen
2018-08-03 14:05 ` joeyli
2018-08-03 16:09 ` Ryan Chen
2018-08-03 18:06 ` joeyli
2018-08-05 10:02 ` Pavel Machek
2018-08-06 8:45 ` Yu Chen
2018-08-06 10:39 ` joeyli
2018-08-07 7:43 ` Yu Chen
2018-08-07 16:27 ` joeyli [this message]
2018-08-08 17:58 ` Pavel Machek
2018-08-09 3:43 ` Yu Chen
2018-08-09 8:12 ` joeyli
2018-08-08 17:50 ` Pavel Machek
2018-08-09 3:01 ` Yu Chen
2018-08-09 6:53 ` Pavel Machek
2018-08-09 9:03 ` Oliver Neukum
2018-08-09 15:55 ` joeyli
2018-08-06 7:57 ` Yu Chen
2018-08-06 9:48 ` joeyli
2018-08-06 10:07 ` Yu Chen
2018-08-06 10:20 ` Oliver Neukum
2018-08-07 7:38 ` Yu Chen
2018-08-07 7:49 ` Ryan Chen
2018-08-07 10:04 ` Oliver Neukum
2018-07-24 14:47 ` joeyli
2018-07-19 14:58 ` joeyli
[not found] ` <edf92acf665b928f02104bb1835fd50723ab9980.1531924968.git.yu.c.chen@intel.com>
2018-07-19 5:32 ` [PATCH 3/4][RFC v2] PM / Hibernate: Encrypt the snapshot pages before submitted to the block device Yu Chen
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