[PATCH v6 0/7] rsa: extend rsa_verify() for UEFI secure boot

[Tom Rini]

On Mon, Jan 27, 2020 at 07:27:33PM +0900, AKASHI Takahiro wrote:

> # This patch set is a prerequisite for UEFI secure boot.
> 
> The current rsa_verify() requires five parameters for a RSA public key
> for efficiency while RSA, in theory, requires only two. In addition,
> those parameters are expected to come from FIT image.
> 
> So this function won't fit very well when we want to use it for the purpose
> of implementing UEFI secure boot, in particular, image authentication
> as well as variable authentication, where the essential two parameters
> are set to be retrieved from one of X509 certificates in signature
> database.
> 
> So, in this patch, additional three parameters will be calculated
> on the fly when rsa_verify() is called without fdt which should contain
> parameters above.
> 
> This calculation heavily relies on "big-number (or multi-precision)
> library." Therefore some routines from BearSSL[1] under MIT license are
> imported in this implementation. See Patch#4.
> # Please let me know if this is not appropriate.
> 
> Prerequisite:
> * public key parser in my "import x509/pkcs7 parser" patch[2]
> 
> # Checkpatch will complain with lots of warnings/errors, but
> # I intentionally don't fix them for maximum maintainability.
> 
>   [1] https://bearssl.org/
>   [2] https://lists.denx.de/pipermail/u-boot/2019-November/390127.html

At this point it needs to be rebased again.  There's a ton of failures
in https://gitlab.denx.de/u-boot/u-boot/pipelines/2198 which is after I
did
https://gitlab.denx.de/u-boot/u-boot/commit/7db0379f85995d8c7673db7b04eb36d96546c9c8
and I'll put a proper commit message on that later today and post it and
CC relevant parties.  It's otherwise looking good.  I do want to confirm
that on boards like minnowmax the slight growth in fit_image_check_sig
is expected.  It's only 6 bytes so it probably is and we get a larger
reduction in rsa_verify all-around.

Thanks!

-- 
Tom
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