Re: [Lsf-pc] [LSF/MM TOPIC] ext4 Encryption Update: Policies, File Names, and Integrity

[Michael Halcrow <mhalcrow@google.com>]

On Thu, Jan 15, 2015 at 01:56:43PM -0500, Sasha Levin wrote:
> On 01/15/2015 01:43 PM, Michael Halcrow wrote:
> > I previously presented on ext4 encryption at the 2014 Linux Security
> > Summit:
> > 
> > http://kernsec.org/wiki/index.php/Linux_Security_Summit_2014/Abstracts/Halcrow
> > 
> > http://kernsec.org/files/lss2014/Halcrow_EXT4_Encryption.pdf
> > 
> > Our first prototype implementation has been in Ted Ts'o's unstable git
> > branch since November 2014. My team has made significant progress in
> > the months since, developing encryption policy and file name
> > encryption capabilities. We have completed the first major phase of
> > development and are preparing a patchset to iterate on the prototype.
> > 
> > I will present our approach at applying different encryption policies
> > to different segments of the file system via a policy inheritance
> > scheme. I will discuss how file-granular policies can sythesize
> > multiple keys to cryptographically protect files. For example, both
> > logon credentials and off-device keys can together preclude access.
> > This work represents efforts by Ildar Muslukhov.
> > 
> > I will also present the challenges involved in file name encryption on
> > a multi-tenant system and will discuss novel solutions spearheaded by
> > Uday Savagaonkar. This approach involves treating the user domain,
> > HTree domain, and disk domains for the file names separately and
> > applying different transformations depending upon whether or not the
> > encryption keys for the file names are available.
> > 
> > Finally, I will discuss what our future plans are with respect to
> > encryption with integrity, which will include leveraging ext4
> > transactions to enforce cryptographic consistency while managing
> > additional per-block authentication data.
> 
> Are there any controversial topics that require a discussion here? It really
> sounds like just a presentation about ext4 encryption.

Yes, it's largely a presentation. I'd be very happy to see this topic
rejected on the grounds that there's too little controversy.