[Buildroot] [PATCH 1/1] package/cryptodev-linux: needs CONFIG_CRYPTO_USER_API_AEAD

[Fabrice Fontaine]

Le mar. 26 avr. 2022 à 23:57, Thomas Petazzoni
<thomas.petazzoni at bootlin.com> a écrit :
>
> On Tue, 26 Apr 2022 23:20:26 +0200
> Fabrice Fontaine <fontaine.fabrice at gmail.com> wrote:
>
> > CONFIG_CRYPTO_USER_API_AEAD is needed to fix the following build
> > failure:
> >
> > ERROR: modpost: "crypto_alloc_skcipher" [/home/autobuild/autobuild/instance-2/output-1/build/cryptodev-linux-1.12/./cryptodev.ko] undefined!
> > ERROR: modpost: "scatterwalk_map_and_copy" [/home/autobuild/autobuild/instance-2/output-1/build/cryptodev-linux-1.12/./cryptodev.ko] undefined!
> > ERROR: modpost: "crypto_ahash_final" [/home/autobuild/autobuild/instance-2/output-1/build/cryptodev-linux-1.12/./cryptodev.ko] undefined!
> > ERROR: modpost: "crypto_aead_encrypt" [/home/autobuild/autobuild/instance-2/output-1/build/cryptodev-linux-1.12/./cryptodev.ko] undefined!
> > ERROR: modpost: "crypto_aead_setkey" [/home/autobuild/autobuild/instance-2/output-1/build/cryptodev-linux-1.12/./cryptodev.ko] undefined!
> > ERROR: modpost: "crypto_skcipher_decrypt" [/home/autobuild/autobuild/instance-2/output-1/build/cryptodev-linux-1.12/./cryptodev.ko] undefined!
> > ERROR: modpost: "crypto_destroy_tfm" [/home/autobuild/autobuild/instance-2/output-1/build/cryptodev-linux-1.12/./cryptodev.ko] undefined!
> > ERROR: modpost: "crypto_skcipher_setkey" [/home/autobuild/autobuild/instance-2/output-1/build/cryptodev-linux-1.12/./cryptodev.ko] undefined!
> > ERROR: modpost: "crypto_aead_decrypt" [/home/autobuild/autobuild/instance-2/output-1/build/cryptodev-linux-1.12/./cryptodev.ko] undefined!
> > ERROR: modpost: "crypto_aead_setauthsize" [/home/autobuild/autobuild/instance-2/output-1/build/cryptodev-linux-1.12/./cryptodev.ko] undefined!
>
> Are you sure of the relationship between these functions and
> CONFIG_CRYPTO_USER_API_AEAD ?
>
> crypto_aead_encrypt() is implemented in crypto/aead.c, which is built
> when CONFIG_CRYPTO_AEAD2=y.
>
> crypto_skcipher_setkey() is implemented in crypto/skcipher.c, which is
> built when CONFIG_CRYPTO_SKCIPHER2=y.
>
> CRYPTO_USER_API_AEAD enables a user-space interface, but here we're
> talking about a kernel-level interface.
>
> Could you clarify?

I'm far from being a kernel or cryptodev-linux expert but here is was
my reasonning:
  - CONFIG_CRYPTO_AEAD2 and CONFIG_CRYPTO_SKCIPHER2 are hidden options
that can't be enabled by KCONFIG_ENABLE_OPT.
  - From my understanding cryptodev-linux allows "userspace
applications to take advantage of hardware accelerators". So, I
assumed that cryptodev-linux needed some sort of userspace API on the
kernel. However, I didn't find a lot of information about this subject
on cryptodev-linux website. It seems that some projects pointed out
that CRYPTO_USER_API_AEAD should be enabled (e.g.
https://github.com/scaleway/kernel-tools/issues/148). Indeed,
CRYPTO_USER_API_AEAD will select CONFIG_CRYPTO_{AEAD,SKCIPHER} (and so
CONFIG_CRYPTO_{AEAD,SKCIPHER}2).

However, as I said, I could be totally wrong, perhaps selecting
CRYPTO_USER_API_AEAD is not correct (even if it fixes the build
failure).
Hopefully, someone with more knowledge of cryptodev-linux should be
able to find the correct fix.

>
> Thomas
> --
> Thomas Petazzoni, co-owner and CEO, Bootlin
> Embedded Linux and Kernel engineering and training
> https://bootlin.com

Best Regards,

Fabrice