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lib: rsa: add rsa_verify_with_pkey()

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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@linaro.org>
Reviewed-by: Simon Glass <sjg@chromium.org>
This commit is contained in:
AKASHI Takahiro 2020-02-21 15:12:59 +09:00 committed by Tom Rini
parent e0d310b098
commit 0cc7a7535f
1 changed files with 64 additions and 1 deletions
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65
lib/rsa/rsa-verify.c
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@ -18,9 +18,22 @@
#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__
/*
* NOTE:
* Since host tools, like mkimage, make use of openssl library for
* RSA encryption, rsa_verify_with_pkey()/rsa_gen_key_prop() are
* of no use and should not be compiled in.
* So just turn off CONFIG_RSA_VERIFY_WITH_PKEY.
*/
#undef CONFIG_RSA_VERIFY_WITH_PKEY
#endif
/* Default public exponent for backward compatibility */
#define RSA_DEFAULT_PUBEXP 65537
@ -271,7 +284,7 @@ out:
}
#endif
#if CONFIG_IS_ENABLED(FIT_SIGNATURE)
#if CONFIG_IS_ENABLED(FIT_SIGNATURE) || IS_ENABLED(CONFIG_RSA_VERIFY_WITH_PKEY)
/**
* rsa_verify_key() - Verify a signature against some data using RSA Key
*
@ -345,6 +358,49 @@ static int rsa_verify_key(struct image_sign_info *info,
}
#endif
#ifdef CONFIG_RSA_VERIFY_WITH_PKEY
/**
* rsa_verify_with_pkey() - Verify a signature against some data using
* only modulus and exponent as RSA key properties.
* @info: Specifies key information
* @hash: Pointer to the expected hash
* @sig: Signature
* @sig_len: Number of bytes in signature
*
* Parse a RSA public key blob in DER format pointed to in @info and fill
* a key_prop structure with properties of the key. Then verify a RSA PKCS1.5
* signature against an expected hash using the calculated properties.
*
* Return 0 if verified, -ve on error
*/
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 */
ret = rsa_gen_key_prop(info->key, info->keylen, &prop);
if (ret) {
debug("Generating necessary parameter for decoding failed\n");
return ret;
}
ret = rsa_verify_key(info, prop, sig, sig_len, hash,
info->crypto->key_len);
rsa_free_key_prop(prop);
return ret;
}
#else
static int rsa_verify_with_pkey(struct image_sign_info *info,
const void *hash, uint8_t *sig, uint sig_len)
{
return -EACCES;
}
#endif
#if CONFIG_IS_ENABLED(FIT_SIGNATURE)
/**
* rsa_verify_with_keynode() - Verify a signature against some data using
@ -435,6 +491,13 @@ int rsa_verify(struct image_sign_info *info,
return -EINVAL;
}
if (IS_ENABLED(CONFIG_RSA_VERIFY_WITH_PKEY) && !info->fdt_blob) {
/* don't rely on fdt properties */
ret = rsa_verify_with_pkey(info, hash, sig, sig_len);
return ret;
}
if (CONFIG_IS_ENABLED(FIT_SIGNATURE)) {
const void *blob = info->fdt_blob;
int ndepth, noffset;