From fc2f4246b4b3b750e8c5aa08440ec5e1c952088e Mon Sep 17 00:00:00 2001 From: Ruchika Gupta Date: Fri, 23 Jan 2015 16:01:50 +0530 Subject: rsa: Split the rsa-verify to separate the modular exponentiation Public exponentiation which is required in rsa verify functionality is tightly integrated with verification code in rsa_verify.c. The patch splits the file into twp separating the modular exponentiation. 1. rsa-verify.c - The file parses device tree keys node to fill a keyprop structure. The keyprop structure can then be converted to implementation specific format. (struct rsa_pub_key for sw implementation) - The parsed device tree node is then passed to a generic rsa_mod_exp function. 2. rsa-mod-exp.c Move the software specific functions related to modular exponentiation from rsa-verify.c to this file. Signed-off-by: Ruchika Gupta CC: Simon Glass Acked-by: Simon Glass --- include/u-boot/rsa-mod-exp.h | 43 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 43 insertions(+) create mode 100644 include/u-boot/rsa-mod-exp.h (limited to 'include') diff --git a/include/u-boot/rsa-mod-exp.h b/include/u-boot/rsa-mod-exp.h new file mode 100644 index 0000000..59cd9ea --- /dev/null +++ b/include/u-boot/rsa-mod-exp.h @@ -0,0 +1,43 @@ +/* + * Copyright (c) 2014, Ruchika Gupta. + * + * SPDX-License-Identifier: GPL-2.0+ +*/ + +#ifndef _RSA_MOD_EXP_H +#define _RSA_MOD_EXP_H + +#include +#include + +/** + * struct key_prop - holder for a public key properties + * + * The struct has pointers to modulus (Typically called N), + * The inverse, R^2, exponent. These can be typecasted and + * used as byte arrays or converted to the required format + * as per requirement of RSA implementation. + */ +struct key_prop { + const void *rr; /* R^2 can be treated as byte array */ + const void *modulus; /* modulus as byte array */ + const void *public_exponent; /* public exponent as byte array */ + uint32_t n0inv; /* -1 / modulus[0] mod 2^32 */ + int num_bits; /* Key length in bits */ + uint32_t exp_len; /* Exponent length in number of uint8_t */ +}; + +/** + * rsa_mod_exp_sw() - Perform RSA Modular Exponentiation in sw + * + * Operation: out[] = sig ^ exponent % modulus + * + * @sig: RSA PKCS1.5 signature + * @sig_len: Length of signature in number of bytes + * @node: Node with RSA key elements like modulus, exponent, R^2, n0inv + * @out: Result in form of byte array + */ +int rsa_mod_exp_sw(const uint8_t *sig, uint32_t sig_len, + struct key_prop *node, uint8_t *out); + +#endif -- cgit v1.1