sof/rimage/pkcs1_5.c

163 lines
4.3 KiB
C

/*
* Copyright (c) 2017, Intel Corporation.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* Author: Liam Girdwood <liam.r.girdwood@linux.intel.com>
* Keyon Jie <yang.jie@linux.intel.com>
*/
#include <openssl/pem.h>
#include <openssl/ssl.h>
#include <openssl/rsa.h>
#include <openssl/evp.h>
#include <openssl/bio.h>
#include <openssl/sha.h>
#include <openssl/objects.h>
#include <openssl/bn.h>
#include <stdio.h>
#include <errno.h>
#include "config.h"
#include "rimage.h"
#include "css.h"
#include "manifest.h"
#if OPENSSL_VERSION_NUMBER < 0x10100000L
void RSA_get0_key(const RSA *r,
const BIGNUM **n, const BIGNUM **e, const BIGNUM **d);
void RSA_get0_key(const RSA *r,
const BIGNUM **n, const BIGNUM **e, const BIGNUM **d)
{
if (n != NULL)
*n = r->n;
if (e != NULL)
*e = r->e;
if (d != NULL)
*d = r->d;
}
#endif
#define DEBUG_PKCS 0
static void bytes_swap(uint8_t *ptr, uint32_t size)
{
uint8_t tmp;
uint32_t index;
for (index = 0; index < (size / 2); index++) {
tmp = ptr[index];
ptr[index] = ptr[size - 1 - index];
ptr[size - 1 - index] = tmp;
}
}
/*
* RSA signature of manifest. The signature is an PKCS
* #1-v1_5 of the entire manifest structure, including all
* extensions, and excluding the last 3 fields of the
* manifest header (Public Key, Exponent and Signature).
*/
int pkcs_sign(struct image *image, struct fw_image_manifest *man,
void *ptr1, unsigned int size1, void *ptr2, unsigned int size2)
{
RSA *priv_rsa = NULL;
EVP_PKEY *privkey;
FILE *fp;
const BIGNUM *n, *e, *d;
unsigned char digest[SHA256_DIGEST_LENGTH], mod[MAN_RSA_KEY_MODULUS_LEN];
unsigned int siglen = MAN_RSA_SIGNATURE_LEN;
char path[256];
int ret = -EINVAL, i;
#if DEBUG_PKCS
fprintf(stdout, "offsets 0x%lx size 0x%x offset 0x%lx size 0x%x\n",
ptr1 - (void *)man, size1, ptr2 - (void *)man, size2);
#endif
/* create new key */
privkey = EVP_PKEY_new();
if (privkey == NULL)
return -ENOMEM;
/* load in RSA private key from PEM file */
if (image->key_name == NULL) {
sprintf(path, "%s/otc_private_key.pem", PEM_KEY_PREFIX);
image->key_name = path;
}
fprintf(stdout, " pkcs: signing with key %s\n", image->key_name);
fp = fopen(image->key_name, "r");
if (fp == NULL) {
fprintf(stderr, "error: can't open file %s %d\n",
image->key_name, -errno);
return -errno;
}
PEM_read_PrivateKey(fp, &privkey, NULL, NULL);
fclose(fp);
/* validate RSA private key */
priv_rsa = EVP_PKEY_get1_RSA(privkey);
if (RSA_check_key(priv_rsa)) {
fprintf(stdout, " pkcs: RSA private key is valid.\n");
} else {
fprintf(stderr, "error: validating RSA private key.\n");
return -EINVAL;
}
/* calculate the digest */
module_sha256_create(image);
module_sha256_update(image, ptr1, size1);
module_sha256_update(image, ptr2, size2);
module_sha256_complete(image, digest);
fprintf(stdout, " pkcs: digest for manifest is ");
for (i = 0; i < SHA256_DIGEST_LENGTH; i++)
fprintf(stdout, "%02x", digest[i]);
fprintf(stdout, "\n");
/* sign the manifest */
ret = RSA_sign(NID_sha256, digest, SHA256_DIGEST_LENGTH,
(unsigned char *)man->css.signature,
&siglen, priv_rsa);
if (ret < 0)
fprintf(stderr, "error: failed to sign manifest\n");
/* copy public key modulus and exponent to manifest */
RSA_get0_key(priv_rsa, &n, &e, &d);
BN_bn2bin(n, mod);
BN_bn2bin(e, (unsigned char *)man->css.exponent);
/* modulus is reveresd */
for (i = 0; i < MAN_RSA_KEY_MODULUS_LEN; i++)
man->css.modulus[i] = mod[MAN_RSA_KEY_MODULUS_LEN - (1 + i)];
/* signature is reveresd, swap it */
bytes_swap(man->css.signature, sizeof(man->css.signature));
EVP_PKEY_free(privkey);
return ret;
}
int ri_manifest_sign(struct image *image)
{
struct fw_image_manifest *man = image->fw_image;
pkcs_sign(image, man, (void *)man + MAN_CSS_HDR_OFFSET,
sizeof(struct css_header) -
(MAN_RSA_KEY_MODULUS_LEN + MAN_RSA_KEY_EXPONENT_LEN +
MAN_RSA_SIGNATURE_LEN),
(void *)man + MAN_SIG_PKG_OFFSET,
(man->css.size - man->css.header_len) * sizeof(uint32_t));
return 0;
}