[U-Boot] [PATCH 5/9] [v3] lib/rsa: Modify rsa to use DM driver if available

[Simon Glass]

Hi Ruchika,

On 23 December 2014 at 04:32, Ruchika Gupta <ruchika.gupta at freescale.com> wrote:
> Modify rsa_verify to use the rsa driver of DM library available.The tools
> and the configurations which don't use Driver Model, will continue to use
> the same RSA sw library. The software implementation of RSA Modular
> Exponentation is now compiled if RSA_MOD_EXP_SW is selected.
>
> Kconfig options are also added for rsa library.
>
> Signed-off-by: Ruchika Gupta <ruchika.gupta at freescale.com>
> CC: Simon Glass <sjg at chromium.org>
> ---
> Changes in v3:
> New patch
>
>  include/configs/am335x_evm.h |  1 +
>  lib/Kconfig                  |  6 +-----
>  lib/rsa/Kconfig              | 31 +++++++++++++++++++++++++++++++
>  lib/rsa/Makefile             |  3 ++-
>  lib/rsa/rsa-verify.c         | 18 ++++++++++++++++++
>  5 files changed, 53 insertions(+), 6 deletions(-)
>  create mode 100644 lib/rsa/Kconfig
>
> diff --git a/include/configs/am335x_evm.h b/include/configs/am335x_evm.h
> index cc36985..aa79841 100644
> --- a/include/configs/am335x_evm.h
> +++ b/include/configs/am335x_evm.h
> @@ -25,6 +25,7 @@
>  # ifdef CONFIG_ENABLE_VBOOT
>  # define CONFIG_FIT_SIGNATURE
>  # define CONFIG_RSA
> +# define CONFIG_RSA_MOD_EXP_SW

This should go in am335x_boneblack_vboot_defconfig I think.

>  # endif
>  #endif
>
> diff --git a/lib/Kconfig b/lib/Kconfig
> index 602dd37..a1f30a2 100644
> --- a/lib/Kconfig
> +++ b/lib/Kconfig
> @@ -27,10 +27,6 @@ config SYS_HZ
>           get_timer() must operate in milliseconds and this option must be
>           set to 1000.
>
> -config RSA
> -       bool "Use RSA Library"
> -       help
> -         RSA support.This enables the RSA algorithm used for FIT image
> -         verification in U-Boot.
> +source lib/rsa/Kconfig
>
>  endmenu
> diff --git a/lib/rsa/Kconfig b/lib/rsa/Kconfig
> new file mode 100644
> index 0000000..8f9aa44
> --- /dev/null
> +++ b/lib/rsa/Kconfig
> @@ -0,0 +1,31 @@
> +config RSA
> +       bool "Use RSA Library"
> +       select RSA_MOD_EXP_SW if !DM
> +       select DM_RSA if DM
> +       help
> +         RSA support.This enables the RSA algorithm used for FIT image
> +         verification in U-Boot.
> +         See doc/uImage.FIT/signature.txt for more details.
> +
> +if RSA && DM_RSA
> +
> +config RSA_SW
> +       bool "User driver Model for RSA Modular Exponentiation in software"
> +       depends on DM && DM_RSA && RSA
> +       select RSA_MOD_EXP_SW
> +       default y
> +       help
> +         Enables driver for modular exponentiation in software. This is a RSA
> +         algorithm used in FIT image verification. It required RSA Key as
> +         input.
> +         See doc/uImage.FIT/signature.txt for more details.
> +
> +endif
> +
> +config RSA_MOD_EXP_SW
> +       bool
> +       default n
> +       help
> +         Library for SW implementation of RSA Modular Exponentiation. This
> +         library is used by the mkimage tool(not selected through this option)
> +         as well as by the RSA driver model with SW implementation.
> diff --git a/lib/rsa/Makefile b/lib/rsa/Makefile
> index cc25b3c..ccc6060 100644
> --- a/lib/rsa/Makefile
> +++ b/lib/rsa/Makefile
> @@ -7,4 +7,5 @@
>  # SPDX-License-Identifier:     GPL-2.0+
>  #
>
> -obj-$(CONFIG_FIT_SIGNATURE) += rsa-verify.o rsa-checksum.o rsa-mod-exp.o
> +obj-$(CONFIG_FIT_SIGNATURE) += rsa-verify.o rsa-checksum.o
> +obj-$(CONFIG_RSA_MOD_EXP_SW) += rsa-mod-exp.o
> diff --git a/lib/rsa/rsa-verify.c b/lib/rsa/rsa-verify.c
> index f8bc086..27f10ef 100644
> --- a/lib/rsa/rsa-verify.c
> +++ b/lib/rsa/rsa-verify.c
> @@ -12,6 +12,7 @@
>  #include <asm/errno.h>
>  #include <asm/types.h>
>  #include <asm/unaligned.h>
> +#include <dm.h>
>  #else
>  #include "fdt_host.h"
>  #include "mkimage.h"
> @@ -43,6 +44,9 @@ static int rsa_verify_key(struct key_prop *prop, const uint8_t *sig,
>         const uint8_t *padding;
>         int pad_len;
>         int ret;
> +#if defined(CONFIG_DM_RSA) && !defined(USE_HOSTCC)
> +       struct udevice *rsa_dev;
> +#endif
>
>         if (!prop || !sig || !hash || !algo)
>                 return -EIO;
> @@ -63,11 +67,25 @@ static int rsa_verify_key(struct key_prop *prop, const uint8_t *sig,
>
>         uint8_t buf[sig_len];
>
> +#if defined(CONFIG_DM_RSA) && !defined(USE_HOSTCC)
> +       ret = uclass_get_device(UCLASS_RSA, 0, &rsa_dev);
> +       if (!ret) {
> +               ret = rsa_mod_exp(rsa_dev, sig, sig_len, prop, buf);
> +               if (ret) {
> +                       debug("Error in Modular exponentation\n");
> +                       return ret;
> +               }
> +       } else {
> +               printf("RSA: Can't find Mod Exp implemnetation\n");
> +               return -EINVAL;
> +       }
> +#else
>         ret = rsa_mod_exp_sw(sig, sig_len, prop, buf);
>         if (ret) {
>                 debug("Error in Modular exponentation\n");
>                 return ret;
>         }
> +#endif

This should use the uclass regardless I think. The software
implementation should just be a driver like the hardware
implementation.

>
>         padding = algo->rsa_padding;
>         pad_len = algo->pad_len - algo->checksum_len;
> --
> 1.8.1.4
>

Regards,
Simon