Re: [PATCH 00/19] RFC, v2: "New" /dev/crypto user-space interface

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From: Ted Ts'o
Date: Friday, August 20, 2010 - 6:56 am

On Fri, Aug 20, 2010 at 10:45:43AM +0200, Miloslav Trmač wrote:

What's the goal of exporting the kernel crypto routines to userspace,
as opposed to just simply doing the crypto in userspace?  Is it to
access hardware crypto accelerators?  (1) I wasn't aware the kernel
crypto routines actually used crypto accelerators, and (2) more often
than not, by the time you take into account the time to move the
crypto context as well as the data into kernel space and back out, and
after you take into account price/performance, most hardware crypto
accellerators have marginal performance benefits; in fact, more often
than not, it's a lose.

If the goal is access to hardware-escrowed keys, don't we have the TPM
interface for that already?

So I'm bit at a list what's the whole point of this patch series.
Could you explain that in the documentation, please?  Especially for
crypto, explaining when something should be used, what the threat
model is, etc., is often very important.

Thanks, regards,

						- Ted


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Messages in current thread:
[PATCH 00/19] RFC, v2: "New" /dev/crypto user-space interface, =?UTF-8?q?Miloslav=2 ..., (Fri Aug 20, 1:45 am)
[PATCH 01/19] User-space API definition, =?UTF-8?q?Miloslav=2 ..., (Fri Aug 20, 1:45 am)
[PATCH 02/19] Add CRYPTO_USERSPACE config option, =?UTF-8?q?Miloslav=2 ..., (Fri Aug 20, 1:45 am)
[PATCH 03/19] Add libtommath headers, =?UTF-8?q?Miloslav=2 ..., (Fri Aug 20, 1:45 am)
[PATCH 04/19] Add libtomcrypt headers, =?UTF-8?q?Miloslav=2 ..., (Fri Aug 20, 1:45 am)
[PATCH 05/19] Add internal /dev/crypto implementation headers, =?UTF-8?q?Miloslav=2 ..., (Fri Aug 20, 1:45 am)
[PATCH 06/19] Add ioctl() argument and attribute handling ..., =?UTF-8?q?Miloslav=2 ..., (Fri Aug 20, 1:45 am)
[PATCH 07/19] Add crypto API utilities., =?UTF-8?q?Miloslav=2 ..., (Fri Aug 20, 1:45 am)
[PATCH 08/19] Add per-process and per-user limits, =?UTF-8?q?Miloslav=2 ..., (Fri Aug 20, 1:45 am)
[PATCH 09/19] Add libtommath implementation, =?UTF-8?q?Miloslav=2 ..., (Fri Aug 20, 1:45 am)
[PATCH 10/19] Add libtomcrypt implementation, =?UTF-8?q?Miloslav=2 ..., (Fri Aug 20, 1:45 am)
[PATCH 10/19] Add libtommath implementation, =?UTF-8?q?Miloslav=2 ..., (Fri Aug 20, 1:45 am)
[PATCH 11/19] Add algorithm properties table., =?UTF-8?q?Miloslav=2 ..., (Fri Aug 20, 1:45 am)
[PATCH 12/19] Add DH implementation and pubkey abstraction ..., =?UTF-8?q?Miloslav=2 ..., (Fri Aug 20, 1:45 am)
[PATCH 13/19] Add /dev/crypto auditing infrastructure, =?UTF-8?q?Miloslav=2 ..., (Fri Aug 20, 1:45 am)
[PATCH 14/19] Add most operations on key objects., =?UTF-8?q?Miloslav=2 ..., (Fri Aug 20, 1:45 am)
[PATCH 15/19] Add key wrapping operations, =?UTF-8?q?Miloslav=2 ..., (Fri Aug 20, 1:45 am)
[PATCH 16/19] Add helpers for zero-copy userspace access, =?UTF-8?q?Miloslav=2 ..., (Fri Aug 20, 1:46 am)
[PATCH 17/19] Add session operations, =?UTF-8?q?Miloslav=2 ..., (Fri Aug 20, 1:46 am)
[PATCH 18/19] Add ioctl handlers, =?UTF-8?q?Miloslav=2 ..., (Fri Aug 20, 1:46 am)
[PATCH 19/19] Finally, add the /dev/crypto device., =?UTF-8?q?Miloslav=2 ..., (Fri Aug 20, 1:46 am)
Re: [PATCH 01/19] User-space API definition, Stefan Richter, (Fri Aug 20, 5:48 am)
Re: [PATCH 00/19] RFC, v2: "New" /dev/crypto user-space in ..., Ted Ts'o, (Fri Aug 20, 6:56 am)
Re: [PATCH 00/19] RFC, v2: "New" /dev/crypto user-space in ..., Nikos Mavrogiannopoulos, (Fri Aug 20, 10:03 am)
Re: [PATCH 01/19] User-space API definition, Randy Dunlap, (Fri Aug 20, 10:12 am)
Re: [PATCH 01/19] User-space API definition, Nikos Mavrogiannopoulos, (Sat Aug 21, 12:35 am)
Re: [PATCH 01/19] User-space API definition, Kyle Moffett, (Sat Aug 21, 6:09 am)
Re: [PATCH 01/19] User-space API definition, Nikos Mavrogiannopoulos, (Sat Aug 21, 7:54 am)
Re: [PATCH 00/19] RFC, v2: "New" /dev/crypto user-space in ..., Nikos Mavrogiannopoulos, (Sun Aug 22, 12:52 am)
Re: [PATCH 01/19] User-space API definition, David Howells, (Sun Aug 22, 3:22 am)
Re: [PATCH 00/19] RFC, v2: "New" /dev/crypto user-space in ..., Nikos Mavrogiannopoulos, (Mon Aug 23, 2:34 am)
Re: [PATCH 01/19] User-space API definition, Herbert Xu, (Fri Sep 3, 2:18 am)
Re: [PATCH 01/19] User-space API definition, Nikos Mavrogiannopoulos, (Fri Sep 3, 2:34 am)
Re: [PATCH 01/19] User-space API definition, Nikos Mavrogiannopoulos, (Fri Sep 3, 8:20 am)