lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  PHC 
Open Source and information security mailing list archives
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date:	Tue, 7 Oct 2014 10:58:27 -0700
From:	Andy Lutomirski <>
To:	Stefan Berger <>
Cc:	Peter Huewe <>,,,
	"" <>,
	LSM List <>,,
	James Morris <>,,
Subject: Re: [TrouSerS-tech] [Ksummit-discuss] TPM MiniSummit @ LinuxCon Europe

On Tue, Oct 7, 2014 at 10:54 AM, Stefan Berger
<> wrote:
> On 09/23/2014 12:42 PM, Andy Lutomirski wrote:
>> On Sep 22, 2014 2:07 AM, "Peter Huewe" <> wrote:
>>> Hi,
>>> I would like to 'invite' all interested parties in a short TPM minisummit
>>> where we can discuss the following hot topics of the TPM subsystem over a
>>> beer or two:
>>>   - State of the TPM Subsystem
>>>   - De-/Initialization Mess
>>>   - Devm'ification
>>>   - Testing
>>>   - TPM 2.0 Support
>>>   - Dependencies / interaction with other subsystems (e.g. keyring / IMA)
>>>   - Status of old 1.1b TPM drivers, deprecation plans
>>>   - ...
>> I am unlikely to be there, but I have a feature request / food for
>> thought:
>> Using a mandatory userspace daemon (e.g. trousers) for TPM access
>> sucks.  Might it be possible to teach the kernel to handle context
>> save and restore and let multiple processes open the device at once?
>> Then a daemon wouldn't be necessary.
> Why add the complexity of swapping of authenticated sessions and keys into
> the kernel if you can handle this in userspace? You need a library that is
> aware of the number of key slots and slots for sessions in the TPM and swaps
> them in at out when applications need them. Trousers is such a library that
> was designed to cope with the limitations of the device and make its
> functionality available to all applications that want to access it.

Trousers is a daemon, not a library, and it's really quite scary.

Admittedly, my information may be a bit out of date, but trousers
contains way too much code (it has layers in the server!), it has
parsers and serializers of questionable safety (I found one critical
bug *by accident* a couple years ago), it listens on a TCP socket
(this should really be a UNIX socket under /run), it's heavy-weight,
and it does far more than necessary (all it needs to do is context

Also, Trousers is quite unfriendly to non-Trousers-using programs
(e.g. chapsd/trunks).

If the kernel helped with context switching, then user programs that
actually want Trousers' functionality could run their own copies.

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
More majordomo info at
Please read the FAQ at

Powered by blists - more mailing lists