[RFC PATCH 0/4] add software ecdsa support

[Philippe Reynes]

This serie adds the support of ecdsa with software
using mbedtls. So boards without ecdsa hardware may
also use signature with ecdsa.

To add the support of ecdsa with mbedtls, I have:
- enabled ecdsa in mbedtls
- add a function sw_ecdsa_verify that uses mbedtls
- add a driver sw_ecdsa that call sw_ecdsa_verify

I have tested this code with sandbox, and I have
followed those steps:

0) build u-boot using sandbox_defconfig and adding those options:
CONFIG_ECDSA_SW=y
CONFIG_ECDSA_MBEDTLS=y
CONFIG_ECDSA=y
CONFIG_ECDSA_VERIFY=y

1) add a signature node to an its file
	signature-256 {
		algo = "sha256,ecdsa256";
		key-name-hint = "private-key-256";
	};

2) generate an ecdsa key
openssl ecparam -name prime256v1 -genkey -noout -out private-key-256.pem

3) create the itb file
./tools/mkimage -f <file.its> -k . -K arch/sandbox/dts/test.dtb <file.itb>

4) launch sandbox u-boot

./u-boot -d arch/sandbox/dts/test.dtb

5) on sandbox u-boot prompt, load the itb and launch bootm on it

=> host load hostfs - 1000000 uboot-ecdsa.itb
4628674 bytes read in 1 ms (4.3 GiB/s)
=> bootm 1000000
...
...
   Verifying Hash Integrity ... sha256,ecdsa256:private-key-256+ OK


I have tested with success ecdsa256 and ecdsa384,
but there is an issue with secp521r1. 


Philippe Reynes (4):
  mbedtls: enable support of ecc
  ecdsa: initial support of ecdsa using mbedtls
  test: lib: sw_ecdsa: add initial test
  drivers: crypto: add software ecdsa support

 drivers/crypto/Kconfig             |   2 +
 drivers/crypto/Makefile            |   1 +
 drivers/crypto/ecdsa/Kconfig       |   6 +
 drivers/crypto/ecdsa/Makefile      |   6 +
 drivers/crypto/ecdsa/ecdsa-sw.c    |  33 +++
 include/crypto/internal/sw_ecdsa.h |  14 +
 lib/mbedtls/Kconfig                |   8 +
 lib/mbedtls/Makefile               |  10 +
 lib/mbedtls/mbedtls_def_config.h   |  18 ++
 lib/mbedtls/sw_ecdsa.c             |  94 ++++++
 test/lib/Makefile                  |   1 +
 test/lib/sw_ecdsa.c                | 445 +++++++++++++++++++++++++++++
 12 files changed, 638 insertions(+)
 create mode 100644 drivers/crypto/ecdsa/Kconfig
 create mode 100644 drivers/crypto/ecdsa/Makefile
 create mode 100644 drivers/crypto/ecdsa/ecdsa-sw.c
 create mode 100644 include/crypto/internal/sw_ecdsa.h
 create mode 100644 lib/mbedtls/sw_ecdsa.c
 create mode 100644 test/lib/sw_ecdsa.c

-- 
2.43.0