topic Re: I.MX6 Cryptographic Acceleration in i.MX Processors

I.MX6 Cryptographic Acceleration

johnlangworthy — Thu, 10 Jan 2013 07:53:38 GMT

The I.MX6 is described as offering cryptographic acceleration in the CAAM. However, as far as I can see, there is no documentation avaialble to support this. Does anybody know what the capabilities are, and how we can access them?

Cheers

Re: I.MX6 Cryptographic Acceleration

Yuri — Thu, 10 Jan 2013 08:18:23 GMT

There is Security Reference Manual for i.MX6 - please apply to local Freescale FAE to get it.
(NDA is required.)

Re: I.MX6 Cryptographic Acceleration

rodz — Thu, 10 Jan 2013 23:08:27 GMT

Hi John,

As Yuri has mentioned above the i.MX 6 Security reference manual contains all the information on CAAM and it's capabilities. This is a moderated document but should not require an NDA. Please contact your local Freescale FAE to obtain access to this document.

At a high level the CAAM is a DMA master supporting the following capabilities:

Secure memory feature with HW enforced access control

Cryptographic authentication

* Hashing algorithms

* MD5

* SHA-1

* SHA-224

* SHA-256

* Message authentication codes (MAC)

* HMAC-all hashing algorithms

* AES-CMAC

* AES-XCBC-MAC

* Auto padding

* ICV checking

Authenticated encryption algorithms

* AES-CCM (counter with CBC-MAC)

Symmetric key block ciphers

* AES (128-bit, 192-bit or 256-bit keys)

* DES (64-bit keys, including key parity)

* 3DES (128-bit or 192-bit keys, including key parity)

Cipher modes

* ECB, CBC, CFB, OFB for all block ciphers

* CTR for AES

Symmetric key stream ciphers

* ArcFour (alleged RC4 with 40 - 128 bit keys)

* Random-number generation

* Entropy is generated via an independent free running ring oscillator

* Oscillator is off when not generating entropy; for lower-power consumption

* NIST-compliant, pseudo random-number generator seeded using hardware generated entropy

The Freescale Linux BSP contains a CAAM driver to make use of the above features. The use of CAAM is via the Linux CryptoAPI. The driver itself is integrated with the Crypto API kernel service in which the algorithms supported by CAAM can replace the native SW implementations.

Regards,

-Rod

Re: I.MX6 Cryptographic Acceleration

markoh — Wed, 23 Jan 2013 17:49:28 GMT

Should there be aes-ccm support in the caam driver? At least for the public linux-imx git repos and mainline linux kernel I can see support for most algorithms but no ccm(aes) support. For example the nx driver registers support for ccm(aes) but he caam does not.

Re: I.MX6 Cryptographic Acceleration

rodz — Fri, 25 Jan 2013 23:15:08 GMT

Support for CCM other capabilities will be added in future releases of the CAAM driver.

-Rod

Re: I.MX6 Cryptographic Acceleration

_benjamindubb — Mon, 04 Mar 2013 20:51:04 GMT

When I include the 'caam' argument in the bootargs I see that the caam driver gets registered with the kernel on startup. But I'm still unable to use it with 'openssl speed -engine cryptodev'. Also the 'openssl engine' shows no caam/cryptodev engine installed. I'm using L3.0.35_1.1.0 version. Any idea?

Thanks,

-Ben

Re: I.MX6 Cryptographic Acceleration

Yuri — Tue, 05 Mar 2013 01:59:36 GMT

As for current BSP CAAM support :

The driver is integrated to the standard Linux cryptographic services interface

known as the Linux Crypto API (or Linux Scatterlist API). All current features

of CAAM, that the driver supports, are via the Linux Crypto API.

Basically Open SSL is able to use a crypto hardware though NetKey API ,
which in turn can use Linux scatterlist crypto API. As for the cryptodev, /dev/crypto
today does not use hardware features of the CAAM, it is just a software implementation.

Re: I.MX6 Cryptographic Acceleration

AlbertT — Tue, 05 Mar 2013 08:08:11 GMT

Hello Yuri,

So we can take advantage of the CAAM using OpenSSL ? Or it is restricted to some functions ?

Jocelyn

Re: I.MX6 Cryptographic Acceleration

Yuri — Tue, 05 Mar 2013 08:29:40 GMT

> So we can take advantage of the CAAM using OpenSSL ?

Yes, if we find Open SSL implementation via scatterlist crypto API.

Re: I.MX6 Cryptographic Acceleration

AlbertT — Tue, 05 Mar 2013 09:13:38 GMT

I don't fully understand, right now, if I use an OpenSSL function for AES encryption for instance, will it take advantage of CAAM or not ? Or should I code everything with Job Descriptor and so on ?

Re: I.MX6 Cryptographic Acceleration

Yuri — Tue, 05 Mar 2013 09:20:25 GMT

If the OpenSSL uses /dev/crypto - we will use software implementation, no CAAM.

Re: I.MX6 Cryptographic Acceleration

AlbertT — Tue, 05 Mar 2013 09:27:15 GMT

Oh ok, and is it possible to force OpenSSL to not use /dev/crypto or we have to wait for a new release of OSSL ?

Re: I.MX6 Cryptographic Acceleration

_benjamindubb — Tue, 05 Mar 2013 14:38:58 GMT

Yura,

are you saying that IPSec will use CAAM driver as long as I include 'caam' in the bootargs?

And for openssl to take advantage of CAAM, do I need to rebuild it? I'm using rootfs from Freescale i.MX6 BSP L3.0.35_1.1.0. Any idea how to configure openssl for it?

Thanks,

-Ben

Re: I.MX6 Cryptographic Acceleration

_benjamindubb — Wed, 06 Mar 2013 00:52:06 GMT

I tried using CAAM with ipsec and it seems like the kernel caam driver crashes. I'm on LTIB kernel 3.0.35-2310 version:

<8004a688>] (dma_sync_sg_for_device+0x18/0x4c) from [<803b290c>] (dma_map_sg_chained+0x48/0xa4)

[<803b290c>] (dma_map_sg_chained+0x48/0xa4) from [<803b4bfc>] (ablkcipher_edesc_alloc.constprop.27+0x3ac/0x3c8)

[<803b4bfc>] (ablkcipher_edesc_alloc.constprop.27+0x3ac/0x3c8) from [<803b4c34>] (ablkcipher_encrypt+0x1c/0x94)

[<803b4c34>] (ablkcipher_encrypt+0x1c/0x94) from [<8020b2bc>] (eseqiv_givencrypt+0x2c8/0x3d0)

[<8020b2bc>] (eseqiv_givencrypt+0x2c8/0x3d0) from [<8021ccc4>] (crypto_authenc_givencrypt+0x64/0x84)

[<8021ccc4>] (crypto_authenc_givencrypt+0x64/0x84) from [<8046daf8>] (esp_output+0x324/0x4bc)

[<8046daf8>] (esp_output+0x324/0x4bc) from [<8047a10c>] (xfrm_output_resume+0x188/0x278)

[<8047a10c>] (xfrm_output_resume+0x188/0x278) from [<80472034>] (xfrm4_output+0x20/0x24)

[<80472034>] (xfrm4_output+0x20/0x24) from [<80434f94>] (ip_local_out+0x28/0x2c)

[<80434f94>] (ip_local_out+0x28/0x2c) from [<8043610c>] (ip_send_skb+0xc/0xd8)

[<8043610c>] (ip_send_skb+0xc/0xd8) from [<80454560>] (udp_send_skb+0xf0/0x3c8)

[<80454560>] (udp_send_skb+0xf0/0x3c8) from [<80456008>] (udp_sendmsg+0x254/0x7f8)

[<80456008>] (udp_sendmsg+0x254/0x7f8) from [<8045d8e8>] (inet_sendmsg+0x94/0xb8)

[<8045d8e8>] (inet_sendmsg+0x94/0xb8) from [<803feb84>] (sock_aio_write+0x114/0x13c)

[<803feb84>] (sock_aio_write+0x114/0x13c) from [<800eff30>] (do_sync_write+0xa4/0xe4)

[<800eff30>] (do_sync_write+0xa4/0xe4) from [<800f06bc>] (vfs_write+0x130/0x138)

[<800f06bc>] (vfs_write+0x130/0x138) from [<800f08a4>] (sys_write+0x40/0x6c)

[<800f08a4>] (sys_write+0x40/0x6c) from [<80040f80>] (ret_fast_syscall+0x0/0x30)

Code: e1a07003 d8bd80f8 e1a04001 e3a05000 (e5940000)

---[ end trace 9693d9778bad1379 ]---

I'm just trying to see what type of improvement to expect from the CAAM driver. I expect the CPU should not be so busy with HW CAAM engine. Any idea how much faster the CAAM engine is compared to plain software implementation?

Thanks,

-Ben

Re: I.MX6 Cryptographic Acceleration

Yuri — Wed, 06 Mar 2013 01:18:35 GMT

Linux CAAM performance estimations may be found under the following discussion.

< https://community.freescale.com/message/313424#313424 >

Re: I.MX6 Cryptographic Acceleration

Yuri — Wed, 06 Mar 2013 01:34:29 GMT

While not officially supported in the SDK, there are userspace interface implementations,

that enable offloading OpenSSL requests to the built-in kernel crypto API, and thus the CAAM

h/w via its respective driver. As known, the AF_ALG family provides the user-space interface

for the kernel crypto API. While a kernel (2.6.38 and later) supports the AF_ALG socket interface,

various third-party cryptodev implementations are also available.

Here are some links to a couple of starting points:

http://carnivore.it/2011/04/23/openssl_-_af_alg

http://home.gna.org/cryptodev-linux/

http://ocf-linux.sourceforge.net/

The enclosed is implementaion from Dipen Patel.

https://community.freescale.com/message/342822#342822

Re: I.MX6 Cryptographic Acceleration

Yuri — Wed, 06 Mar 2013 01:41:43 GMT

Linux kernel contains various users of the Scatterlist CryptoAPI, including its IPSec implementation, sometimes referred to as the NETKEY stack.

Re: I.MX6 Cryptographic Acceleration

_benjamindubb — Wed, 06 Mar 2013 02:57:53 GMT

I get "Unauthorized" when I click on the link you provided. Do I need to ask my FAE for special access to this "secret" data?

Re: I.MX6 Cryptographic Acceleration

_benjamindubb — Wed, 06 Mar 2013 02:59:55 GMT

Where can I find the latest CAAM patches that address the issue reported by the callstack above?

Re: I.MX6 Cryptographic Acceleration

AlbertT — Wed, 06 Mar 2013 15:45:07 GMT

What do you mean by bootargs ? Where do you put caam ?