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

Simon Glass
2014-12-24T00:49:10Z

Hi Ruchika,

On 23 December 2014 at 04:32, Ruchika Gupta <ruchika.gupta@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@freescale.com>
> CC: Simon Glass <sjg@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