[U-Boot] [PATCH v1 3/3] lib: rsa: add rsa_verify_with_pkey()

[AKASHI Takahiro]

On Wed, Oct 09, 2019 at 02:30:44PM +0900, AKASHI Takahiro wrote:
> This function, and hence rsa_verify(), will perform RSA verification
> with two essential parameters for a RSA public key in contract of
> rsa_verify_with_keynode(), which requires additional three parameters
> stored in FIT image.
> 
> It will be used in implementing UEFI secure boot, i.e. image authentication
> and variable authentication.
> 
> Signed-off-by: AKASHI Takahiro <takahiro.akashi at linaro.org>
> ---
>  lib/rsa/Kconfig      |  7 -----
>  lib/rsa/Makefile     |  1 -
>  lib/rsa/rsa-verify.c | 63 ++++++++++++++++++++++++++++++++++++++------
>  3 files changed, 55 insertions(+), 16 deletions(-)
> 
> diff --git a/lib/rsa/Kconfig b/lib/rsa/Kconfig
> index d1743d7a4c47..62b7ab9c5e5c 100644
> --- a/lib/rsa/Kconfig
> +++ b/lib/rsa/Kconfig
> @@ -30,13 +30,6 @@ config RSA_VERIFY
>  	help
>  	  Add RSA signature verification support.
>  
> -config RSA_VERIFY_WITH_PKEY
> -	bool "Execute RSA verification without key parameters from FDT"
> -	depends on RSA
> -	help
> -	  This options enables RSA signature verification without
> -	  using public key parameters which is embedded control FDT.
> -
>  config RSA_SOFTWARE_EXP
>  	bool "Enable driver for RSA Modular Exponentiation in software"
>  	depends on DM
> diff --git a/lib/rsa/Makefile b/lib/rsa/Makefile
> index 14ed3cb4012b..c07305188e0c 100644
> --- a/lib/rsa/Makefile
> +++ b/lib/rsa/Makefile
> @@ -6,5 +6,4 @@
>  # Wolfgang Denk, DENX Software Engineering, wd at denx.de.
>  
>  obj-$(CONFIG_$(SPL_)RSA_VERIFY) += rsa-verify.o rsa-checksum.o
> -obj-$(CONFIG_RSA_VERIFY_WITH_PKEY) += rsa-keyprop.o
>  obj-$(CONFIG_RSA_SOFTWARE_EXP) += rsa-mod-exp.o

Oops, those changes above against Kconfig and Makefile are wrong.
They should not be included in this commit. By removing them,
everything will work well.
# Those hunks are remnants from last-minute cleanup.

Thanks,
-Takahiro Akashi

> diff --git a/lib/rsa/rsa-verify.c b/lib/rsa/rsa-verify.c
> index 1df42f28c64a..ce79984b30f9 100644
> --- a/lib/rsa/rsa-verify.c
> +++ b/lib/rsa/rsa-verify.c
> @@ -17,9 +17,14 @@
>  #include "mkimage.h"
>  #include <fdt_support.h>
>  #endif
> +#include <linux/kconfig.h>
>  #include <u-boot/rsa-mod-exp.h>
>  #include <u-boot/rsa.h>
>  
> +#ifndef __UBOOT__ /* for host tools */
> +#undef CONFIG_RSA_VERIFY_WITH_PKEY
> +#endif
> +
>  /* Default public exponent for backward compatibility */
>  #define RSA_DEFAULT_PUBEXP	65537
>  
> @@ -344,6 +349,34 @@ static int rsa_verify_key(struct image_sign_info *info,
>  }
>  #endif
>  
> +#ifdef CONFIG_RSA_VERIFY_WITH_PKEY
> +/**
> + * rsa_verify_with_pkey()
> + *
> + */
> +static int rsa_verify_with_pkey(struct image_sign_info *info,
> +				const void *hash, uint8_t *sig, uint sig_len)
> +{
> +	struct key_prop *prop;
> +	int ret;
> +
> +	/* Public key is self-described to fill key_prop */
> +	prop = rsa_gen_key_prop(info->key, info->keylen);
> +	if (!prop) {
> +		debug("Generating necessary parameter for decoding failed\n");
> +		return -EACCES;
> +	}
> +
> +	ret = rsa_verify_key(info, prop, sig, sig_len, hash,
> +			     info->crypto->key_len);
> +
> +	rsa_free_key_prop(prop);
> +
> +	return ret;
> +}
> +#endif
> +
> +#if CONFIG_IS_ENABLED(FIT_SIGNATURE)
>  /**
>   * rsa_verify_with_keynode() - Verify a signature against some data using
>   * information in node with prperties of RSA Key like modulus, exponent etc.
> @@ -397,18 +430,21 @@ static int rsa_verify_with_keynode(struct image_sign_info *info,
>  
>  	return ret;
>  }
> +#endif
>  
>  int rsa_verify(struct image_sign_info *info,
>  	       const struct image_region region[], int region_count,
>  	       uint8_t *sig, uint sig_len)
>  {
> -	const void *blob = info->fdt_blob;
>  	/* Reserve memory for maximum checksum-length */
>  	uint8_t hash[info->crypto->key_len];
> +	int ret = -EACCES;
> +#if CONFIG_IS_ENABLED(FIT_SIGNATURE)
> +	const void *blob = info->fdt_blob;
>  	int ndepth, noffset;
>  	int sig_node, node;
>  	char name[100];
> -	int ret;
> +#endif
>  
>  	/*
>  	 * Verify that the checksum-length does not exceed the
> @@ -421,12 +457,6 @@ int rsa_verify(struct image_sign_info *info,
>  		return -EINVAL;
>  	}
>  
> -	sig_node = fdt_subnode_offset(blob, 0, FIT_SIG_NODENAME);
> -	if (sig_node < 0) {
> -		debug("%s: No signature node found\n", __func__);
> -		return -ENOENT;
> -	}
> -
>  	/* Calculate checksum with checksum-algorithm */
>  	ret = info->checksum->calculate(info->checksum->name,
>  					region, region_count, hash);
> @@ -435,6 +465,22 @@ int rsa_verify(struct image_sign_info *info,
>  		return -EINVAL;
>  	}
>  
> +#ifdef CONFIG_RSA_VERIFY_WITH_PKEY
> +	if (!info->fdt_blob) {
> +		/* don't rely on fdt properties */
> +		ret = rsa_verify_with_pkey(info, hash, sig, sig_len);
> +
> +		return ret;
> +	}
> +#endif
> +
> +#if CONFIG_IS_ENABLED(FIT_SIGNATURE)
> +	sig_node = fdt_subnode_offset(blob, 0, FIT_SIG_NODENAME);
> +	if (sig_node < 0) {
> +		debug("%s: No signature node found\n", __func__);
> +		return -ENOENT;
> +	}
> +
>  	/* See if we must use a particular key */
>  	if (info->required_keynode != -1) {
>  		ret = rsa_verify_with_keynode(info, hash, sig, sig_len,
> @@ -461,6 +507,7 @@ int rsa_verify(struct image_sign_info *info,
>  				break;
>  		}
>  	}
> +#endif
>  
>  	return ret;
>  }
> -- 
> 2.21.0
>