[people/ms/u-boot.git] / lib / rsa / rsa-sign.c

/*
 * Copyright (c) 2013, Google Inc.
 *
 * SPDX-License-Identifier:	GPL-2.0+
 */

#include "mkimage.h"
#include <stdio.h>
#include <string.h>
#include <image.h>
#include <time.h>
#include <openssl/rsa.h>
#include <openssl/pem.h>
#include <openssl/err.h>
#include <openssl/ssl.h>
#include <openssl/evp.h>

#if OPENSSL_VERSION_NUMBER >= 0x10000000L
#define HAVE_ERR_REMOVE_THREAD_STATE
#endif

static int rsa_err(const char *msg)
{
	unsigned long sslErr = ERR_get_error();

	fprintf(stderr, "%s", msg);
	fprintf(stderr, ": %s\n",
		ERR_error_string(sslErr, 0));

	return -1;
}

/**
 * rsa_get_pub_key() - read a public key from a .crt file
 *
 * @keydir:	Directory containins the key
 * @name	Name of key file (will have a .crt extension)
 * @rsap	Returns RSA object, or NULL on failure
 * @return 0 if ok, -ve on error (in which case *rsap will be set to NULL)
 */
static int rsa_get_pub_key(const char *keydir, const char *name, RSA **rsap)
{
	char path[1024];
	EVP_PKEY *key;
	X509 *cert;
	RSA *rsa;
	FILE *f;
	int ret;

	*rsap = NULL;
	snprintf(path, sizeof(path), "%s/%s.crt", keydir, name);
	f = fopen(path, "r");
	if (!f) {
		fprintf(stderr, "Couldn't open RSA certificate: '%s': %s\n",
			path, strerror(errno));
		return -EACCES;
	}

	/* Read the certificate */
	cert = NULL;
	if (!PEM_read_X509(f, &cert, NULL, NULL)) {
		rsa_err("Couldn't read certificate");
		ret = -EINVAL;
		goto err_cert;
	}

	/* Get the public key from the certificate. */
	key = X509_get_pubkey(cert);
	if (!key) {
		rsa_err("Couldn't read public key\n");
		ret = -EINVAL;
		goto err_pubkey;
	}

	/* Convert to a RSA_style key. */
	rsa = EVP_PKEY_get1_RSA(key);
	if (!rsa) {
		rsa_err("Couldn't convert to a RSA style key");
		ret = -EINVAL;
		goto err_rsa;
	}
	fclose(f);
	EVP_PKEY_free(key);
	X509_free(cert);
	*rsap = rsa;

	return 0;

err_rsa:
	EVP_PKEY_free(key);
err_pubkey:
	X509_free(cert);
err_cert:
	fclose(f);
	return ret;
}

/**
 * rsa_get_priv_key() - read a private key from a .key file
 *
 * @keydir:	Directory containins the key
 * @name	Name of key file (will have a .key extension)
 * @rsap	Returns RSA object, or NULL on failure
 * @return 0 if ok, -ve on error (in which case *rsap will be set to NULL)
 */
static int rsa_get_priv_key(const char *keydir, const char *name, RSA **rsap)
{
	char path[1024];
	RSA *rsa;
	FILE *f;

	*rsap = NULL;
	snprintf(path, sizeof(path), "%s/%s.key", keydir, name);
	f = fopen(path, "r");
	if (!f) {
		fprintf(stderr, "Couldn't open RSA private key: '%s': %s\n",
			path, strerror(errno));
		return -ENOENT;
	}

	rsa = PEM_read_RSAPrivateKey(f, 0, NULL, path);
	if (!rsa) {
		rsa_err("Failure reading private key");
		fclose(f);
		return -EPROTO;
	}
	fclose(f);
	*rsap = rsa;

	return 0;
}

static int rsa_init(void)
{
	int ret;

	ret = SSL_library_init();
	if (!ret) {
		fprintf(stderr, "Failure to init SSL library\n");
		return -1;
	}
	SSL_load_error_strings();

	OpenSSL_add_all_algorithms();
	OpenSSL_add_all_digests();
	OpenSSL_add_all_ciphers();

	return 0;
}

static void rsa_remove(void)
{
	CRYPTO_cleanup_all_ex_data();
	ERR_free_strings();
#ifdef HAVE_ERR_REMOVE_THREAD_STATE
	ERR_remove_thread_state(NULL);
#else
	ERR_remove_state(0);
#endif
	EVP_cleanup();
}

static int rsa_sign_with_key(RSA *rsa, struct checksum_algo *checksum_algo,
		const struct image_region region[], int region_count,
		uint8_t **sigp, uint *sig_size)
{
	EVP_PKEY *key;
	EVP_MD_CTX *context;
	int size, ret = 0;
	uint8_t *sig;
	int i;

	key = EVP_PKEY_new();
	if (!key)
		return rsa_err("EVP_PKEY object creation failed");

	if (!EVP_PKEY_set1_RSA(key, rsa)) {
		ret = rsa_err("EVP key setup failed");
		goto err_set;
	}

	size = EVP_PKEY_size(key);
	sig = malloc(size);
	if (!sig) {
		fprintf(stderr, "Out of memory for signature (%d bytes)\n",
			size);
		ret = -ENOMEM;
		goto err_alloc;
	}

	context = EVP_MD_CTX_create();
	if (!context) {
		ret = rsa_err("EVP context creation failed");
		goto err_create;
	}
	EVP_MD_CTX_init(context);
	if (!EVP_SignInit(context, checksum_algo->calculate_sign())) {
		ret = rsa_err("Signer setup failed");
		goto err_sign;
	}

	for (i = 0; i < region_count; i++) {
		if (!EVP_SignUpdate(context, region[i].data, region[i].size)) {
			ret = rsa_err("Signing data failed");
			goto err_sign;
		}
	}

	if (!EVP_SignFinal(context, sig, sig_size, key)) {
		ret = rsa_err("Could not obtain signature");
		goto err_sign;
	}
	EVP_MD_CTX_cleanup(context);
	EVP_MD_CTX_destroy(context);
	EVP_PKEY_free(key);

	debug("Got signature: %d bytes, expected %d\n", *sig_size, size);
	*sigp = sig;
	*sig_size = size;

	return 0;

err_sign:
	EVP_MD_CTX_destroy(context);
err_create:
	free(sig);
err_alloc:
err_set:
	EVP_PKEY_free(key);
	return ret;
}

int rsa_sign(struct image_sign_info *info,
	     const struct image_region region[], int region_count,
	     uint8_t **sigp, uint *sig_len)
{
	RSA *rsa;
	int ret;

	ret = rsa_init();
	if (ret)
		return ret;

	ret = rsa_get_priv_key(info->keydir, info->keyname, &rsa);
	if (ret)
		goto err_priv;
	ret = rsa_sign_with_key(rsa, info->algo->checksum, region,
				region_count, sigp, sig_len);
	if (ret)
		goto err_sign;

	RSA_free(rsa);
	rsa_remove();

	return ret;

err_sign:
	RSA_free(rsa);
err_priv:
	rsa_remove();
	return ret;
}

/*
 * rsa_get_exponent(): - Get the public exponent from an RSA key
 */
static int rsa_get_exponent(RSA *key, uint64_t *e)
{
	int ret;
	BIGNUM *bn_te;
	uint64_t te;

	ret = -EINVAL;
	bn_te = NULL;

	if (!e)
		goto cleanup;

	if (BN_num_bits(key->e) > 64)
		goto cleanup;

	*e = BN_get_word(key->e);

	if (BN_num_bits(key->e) < 33) {
		ret = 0;
		goto cleanup;
	}

	bn_te = BN_dup(key->e);
	if (!bn_te)
		goto cleanup;

	if (!BN_rshift(bn_te, bn_te, 32))
		goto cleanup;

	if (!BN_mask_bits(bn_te, 32))
		goto cleanup;

	te = BN_get_word(bn_te);
	te <<= 32;
	*e |= te;
	ret = 0;

cleanup:
	if (bn_te)
		BN_free(bn_te);

	return ret;
}

/*
 * rsa_get_params(): - Get the important parameters of an RSA public key
 */
int rsa_get_params(RSA *key, uint64_t *exponent, uint32_t *n0_invp,
		   BIGNUM **modulusp, BIGNUM **r_squaredp)
{
	BIGNUM *big1, *big2, *big32, *big2_32;
	BIGNUM *n, *r, *r_squared, *tmp;
	BN_CTX *bn_ctx = BN_CTX_new();
	int ret = 0;

	/* Initialize BIGNUMs */
	big1 = BN_new();
	big2 = BN_new();
	big32 = BN_new();
	r = BN_new();
	r_squared = BN_new();
	tmp = BN_new();
	big2_32 = BN_new();
	n = BN_new();
	if (!big1 || !big2 || !big32 || !r || !r_squared || !tmp || !big2_32 ||
	    !n) {
		fprintf(stderr, "Out of memory (bignum)\n");
		return -ENOMEM;
	}

	if (0 != rsa_get_exponent(key, exponent))
		ret = -1;

	if (!BN_copy(n, key->n) || !BN_set_word(big1, 1L) ||
	    !BN_set_word(big2, 2L) || !BN_set_word(big32, 32L))
		ret = -1;

	/* big2_32 = 2^32 */
	if (!BN_exp(big2_32, big2, big32, bn_ctx))
		ret = -1;

	/* Calculate n0_inv = -1 / n[0] mod 2^32 */
	if (!BN_mod_inverse(tmp, n, big2_32, bn_ctx) ||
	    !BN_sub(tmp, big2_32, tmp))
		ret = -1;
	*n0_invp = BN_get_word(tmp);

	/* Calculate R = 2^(# of key bits) */
	if (!BN_set_word(tmp, BN_num_bits(n)) ||
	    !BN_exp(r, big2, tmp, bn_ctx))
		ret = -1;

	/* Calculate r_squared = R^2 mod n */
	if (!BN_copy(r_squared, r) ||
	    !BN_mul(tmp, r_squared, r, bn_ctx) ||
	    !BN_mod(r_squared, tmp, n, bn_ctx))
		ret = -1;

	*modulusp = n;
	*r_squaredp = r_squared;

	BN_free(big1);
	BN_free(big2);
	BN_free(big32);
	BN_free(r);
	BN_free(tmp);
	BN_free(big2_32);
	if (ret) {
		fprintf(stderr, "Bignum operations failed\n");
		return -ENOMEM;
	}

	return ret;
}

static int fdt_add_bignum(void *blob, int noffset, const char *prop_name,
			  BIGNUM *num, int num_bits)
{
	int nwords = num_bits / 32;
	int size;
	uint32_t *buf, *ptr;
	BIGNUM *tmp, *big2, *big32, *big2_32;
	BN_CTX *ctx;
	int ret;

	tmp = BN_new();
	big2 = BN_new();
	big32 = BN_new();
	big2_32 = BN_new();
	if (!tmp || !big2 || !big32 || !big2_32) {
		fprintf(stderr, "Out of memory (bignum)\n");
		return -ENOMEM;
	}
	ctx = BN_CTX_new();
	if (!tmp) {
		fprintf(stderr, "Out of memory (bignum context)\n");
		return -ENOMEM;
	}
	BN_set_word(big2, 2L);
	BN_set_word(big32, 32L);
	BN_exp(big2_32, big2, big32, ctx); /* B = 2^32 */

	size = nwords * sizeof(uint32_t);
	buf = malloc(size);
	if (!buf) {
		fprintf(stderr, "Out of memory (%d bytes)\n", size);
		return -ENOMEM;
	}

	/* Write out modulus as big endian array of integers */
	for (ptr = buf + nwords - 1; ptr >= buf; ptr--) {
		BN_mod(tmp, num, big2_32, ctx); /* n = N mod B */
		*ptr = cpu_to_fdt32(BN_get_word(tmp));
		BN_rshift(num, num, 32); /*  N = N/B */
	}

	/*
	 * We try signing with successively increasing size values, so this
	 * might fail several times
	 */
	ret = fdt_setprop(blob, noffset, prop_name, buf, size);
	if (ret)
		return -FDT_ERR_NOSPACE;
	free(buf);
	BN_free(tmp);
	BN_free(big2);
	BN_free(big32);
	BN_free(big2_32);

	return ret;
}

int rsa_add_verify_data(struct image_sign_info *info, void *keydest)
{
	BIGNUM *modulus, *r_squared;
	uint64_t exponent;
	uint32_t n0_inv;
	int parent, node;
	char name[100];
	int ret;
	int bits;
	RSA *rsa;

	debug("%s: Getting verification data\n", __func__);
	ret = rsa_get_pub_key(info->keydir, info->keyname, &rsa);
	if (ret)
		return ret;
	ret = rsa_get_params(rsa, &exponent, &n0_inv, &modulus, &r_squared);
	if (ret)
		return ret;
	bits = BN_num_bits(modulus);
	parent = fdt_subnode_offset(keydest, 0, FIT_SIG_NODENAME);
	if (parent == -FDT_ERR_NOTFOUND) {
		parent = fdt_add_subnode(keydest, 0, FIT_SIG_NODENAME);
		if (parent < 0) {
			ret = parent;
			if (ret != -FDT_ERR_NOSPACE) {
				fprintf(stderr, "Couldn't create signature node: %s\n",
					fdt_strerror(parent));
			}
		}
	}
	if (ret)
		goto done;

	/* Either create or overwrite the named key node */
	snprintf(name, sizeof(name), "key-%s", info->keyname);
	node = fdt_subnode_offset(keydest, parent, name);
	if (node == -FDT_ERR_NOTFOUND) {
		node = fdt_add_subnode(keydest, parent, name);
		if (node < 0) {
			ret = node;
			if (ret != -FDT_ERR_NOSPACE) {
				fprintf(stderr, "Could not create key subnode: %s\n",
					fdt_strerror(node));
			}
		}
	} else if (node < 0) {
		fprintf(stderr, "Cannot select keys parent: %s\n",
			fdt_strerror(node));
		ret = node;
	}

	if (!ret) {
		ret = fdt_setprop_string(keydest, node, "key-name-hint",
				 info->keyname);
	}
	if (!ret)
		ret = fdt_setprop_u32(keydest, node, "rsa,num-bits", bits);
	if (!ret)
		ret = fdt_setprop_u32(keydest, node, "rsa,n0-inverse", n0_inv);
	if (!ret) {
		ret = fdt_setprop_u64(keydest, node, "rsa,exponent", exponent);
	}
	if (!ret) {
		ret = fdt_add_bignum(keydest, node, "rsa,modulus", modulus,
				     bits);
	}
	if (!ret) {
		ret = fdt_add_bignum(keydest, node, "rsa,r-squared", r_squared,
				     bits);
	}
	if (!ret) {
		ret = fdt_setprop_string(keydest, node, FIT_ALGO_PROP,
					 info->algo->name);
	}
	if (!ret && info->require_keys) {
		ret = fdt_setprop_string(keydest, node, "required",
					 info->require_keys);
	}
done:
	BN_free(modulus);
	BN_free(r_squared);
	if (ret)
		return ret == -FDT_ERR_NOSPACE ? -ENOSPC : -EIO;

	return 0;
}
Commit	Line	Data
19c402af SG	1	/*
	2	* Copyright (c) 2013, Google Inc.
	3	*
1a459660	4	* SPDX-License-Identifier: GPL-2.0+
19c402af SG	5	*/
	6
	7	#include "mkimage.h"
	8	#include <stdio.h>
	9	#include <string.h>
19c402af SG	10	#include <image.h>
	11	#include <time.h>
	12	#include <openssl/rsa.h>
	13	#include <openssl/pem.h>
	14	#include <openssl/err.h>
	15	#include <openssl/ssl.h>
	16	#include <openssl/evp.h>
	17
	18	#if OPENSSL_VERSION_NUMBER >= 0x10000000L
	19	#define HAVE_ERR_REMOVE_THREAD_STATE
	20	#endif
	21
	22	static int rsa_err(const char *msg)
	23	{
	24	unsigned long sslErr = ERR_get_error();
	25
	26	fprintf(stderr, "%s", msg);
	27	fprintf(stderr, ": %s\n",
	28	ERR_error_string(sslErr, 0));
	29
	30	return -1;
	31	}
	32
	33	/**
	34	* rsa_get_pub_key() - read a public key from a .crt file
	35	*
	36	* @keydir: Directory containins the key
	37	* @name Name of key file (will have a .crt extension)
	38	* @rsap Returns RSA object, or NULL on failure
	39	* @return 0 if ok, -ve on error (in which case *rsap will be set to NULL)
	40	*/
	41	static int rsa_get_pub_key(const char keydir, const char name, RSA **rsap)
	42	{
	43	char path[1024];
	44	EVP_PKEY *key;
	45	X509 *cert;
	46	RSA *rsa;
	47	FILE *f;
	48	int ret;
	49
	50	*rsap = NULL;
	51	snprintf(path, sizeof(path), "%s/%s.crt", keydir, name);
	52	f = fopen(path, "r");
	53	if (!f) {
	54	fprintf(stderr, "Couldn't open RSA certificate: '%s': %s\n",
	55	path, strerror(errno));
	56	return -EACCES;
	57	}
	58
	59	/* Read the certificate */
	60	cert = NULL;
	61	if (!PEM_read_X509(f, &cert, NULL, NULL)) {
	62	rsa_err("Couldn't read certificate");
	63	ret = -EINVAL;
	64	goto err_cert;
	65	}
	66
	67	/* Get the public key from the certificate. */
	68	key = X509_get_pubkey(cert);
	69	if (!key) {
	70	rsa_err("Couldn't read public key\n");
	71	ret = -EINVAL;
	72	goto err_pubkey;
	73	}
74
75	/* Convert to a RSA_style key. */
76	rsa = EVP_PKEY_get1_RSA(key);
77	if (!rsa) {
78	rsa_err("Couldn't convert to a RSA style key");
54267162	79	ret = -EINVAL;
19c402af SG	80	goto err_rsa;
	81	}
	82	fclose(f);
	83	EVP_PKEY_free(key);
	84	X509_free(cert);
	85	*rsap = rsa;
	86
	87	return 0;
	88
	89	err_rsa:
	90	EVP_PKEY_free(key);
	91	err_pubkey:
	92	X509_free(cert);
	93	err_cert:
	94	fclose(f);
	95	return ret;
	96	}
	97
	98	/**
	99	* rsa_get_priv_key() - read a private key from a .key file
	100	*
	101	* @keydir: Directory containins the key
	102	* @name Name of key file (will have a .key extension)
	103	* @rsap Returns RSA object, or NULL on failure
	104	* @return 0 if ok, -ve on error (in which case *rsap will be set to NULL)
	105	*/
	106	static int rsa_get_priv_key(const char keydir, const char name, RSA **rsap)
	107	{
	108	char path[1024];
	109	RSA *rsa;
	110	FILE *f;
	111
	112	*rsap = NULL;
	113	snprintf(path, sizeof(path), "%s/%s.key", keydir, name);
	114	f = fopen(path, "r");
	115	if (!f) {
	116	fprintf(stderr, "Couldn't open RSA private key: '%s': %s\n",
	117	path, strerror(errno));
	118	return -ENOENT;
	119	}
	120
	121	rsa = PEM_read_RSAPrivateKey(f, 0, NULL, path);
	122	if (!rsa) {
	123	rsa_err("Failure reading private key");
	124	fclose(f);
	125	return -EPROTO;
	126	}
	127	fclose(f);
	128	*rsap = rsa;
	129
	130	return 0;
	131	}
	132
	133	static int rsa_init(void)
	134	{
	135	int ret;
	136
	137	ret = SSL_library_init();
	138	if (!ret) {
	139	fprintf(stderr, "Failure to init SSL library\n");
	140	return -1;
	141	}
	142	SSL_load_error_strings();
	143
144	OpenSSL_add_all_algorithms();
145	OpenSSL_add_all_digests();
146	OpenSSL_add_all_ciphers();
147
148	return 0;
149	}
150
151	static void rsa_remove(void)
152	{
153	CRYPTO_cleanup_all_ex_data();
154	ERR_free_strings();
155	#ifdef HAVE_ERR_REMOVE_THREAD_STATE
156	ERR_remove_thread_state(NULL);
157	#else
158	ERR_remove_state(0);
159	#endif
160	EVP_cleanup();
161	}
162
646257d1 HS	163	static int rsa_sign_with_key(RSA rsa, struct checksum_algo checksum_algo,
	164	const struct image_region region[], int region_count,
	165	uint8_t *sigp, uint sig_size)
19c402af SG	166	{
	167	EVP_PKEY *key;
	168	EVP_MD_CTX *context;
	169	int size, ret = 0;
	170	uint8_t *sig;
	171	int i;
	172
	173	key = EVP_PKEY_new();
	174	if (!key)
	175	return rsa_err("EVP_PKEY object creation failed");
	176
	177	if (!EVP_PKEY_set1_RSA(key, rsa)) {
	178	ret = rsa_err("EVP key setup failed");
	179	goto err_set;
	180	}
	181
	182	size = EVP_PKEY_size(key);
	183	sig = malloc(size);
	184	if (!sig) {
	185	fprintf(stderr, "Out of memory for signature (%d bytes)\n",
	186	size);
	187	ret = -ENOMEM;
	188	goto err_alloc;
	189	}
	190
	191	context = EVP_MD_CTX_create();
	192	if (!context) {
	193	ret = rsa_err("EVP context creation failed");
	194	goto err_create;
	195	}
	196	EVP_MD_CTX_init(context);
29a23f9d	197	if (!EVP_SignInit(context, checksum_algo->calculate_sign())) {
19c402af SG	198	ret = rsa_err("Signer setup failed");
	199	goto err_sign;
	200	}
	201
	202	for (i = 0; i < region_count; i++) {
	203	if (!EVP_SignUpdate(context, region[i].data, region[i].size)) {
	204	ret = rsa_err("Signing data failed");
	205	goto err_sign;
	206	}
	207	}
	208
	209	if (!EVP_SignFinal(context, sig, sig_size, key)) {
	210	ret = rsa_err("Could not obtain signature");
	211	goto err_sign;
	212	}
	213	EVP_MD_CTX_cleanup(context);
	214	EVP_MD_CTX_destroy(context);
	215	EVP_PKEY_free(key);
	216
	217	debug("Got signature: %d bytes, expected %d\n", *sig_size, size);
	218	*sigp = sig;
	219	*sig_size = size;
	220
	221	return 0;
	222
	223	err_sign:
	224	EVP_MD_CTX_destroy(context);
	225	err_create:
	226	free(sig);
	227	err_alloc:
	228	err_set:
	229	EVP_PKEY_free(key);
	230	return ret;
	231	}
	232
	233	int rsa_sign(struct image_sign_info *info,
	234	const struct image_region region[], int region_count,
	235	uint8_t *sigp, uint sig_len)
	236	{
	237	RSA *rsa;
	238	int ret;
	239
	240	ret = rsa_init();
	241	if (ret)
	242	return ret;
	243
	244	ret = rsa_get_priv_key(info->keydir, info->keyname, &rsa);
	245	if (ret)
	246	goto err_priv;
646257d1 HS	247	ret = rsa_sign_with_key(rsa, info->algo->checksum, region,
646257d1 HS	248	region_count, sigp, sig_len);
19c402af SG	249	if (ret)
	250	goto err_sign;
	251
	252	RSA_free(rsa);
	253	rsa_remove();
	254
	255	return ret;
	256
	257	err_sign:
	258	RSA_free(rsa);
	259	err_priv:
	260	rsa_remove();
	261	return ret;
	262	}
	263
e0f2f155 MW	264	/*
	265	* rsa_get_exponent(): - Get the public exponent from an RSA key
	266	*/
	267	static int rsa_get_exponent(RSA key, uint64_t e)
	268	{
	269	int ret;
	270	BIGNUM *bn_te;
	271	uint64_t te;
	272
	273	ret = -EINVAL;
	274	bn_te = NULL;
	275
	276	if (!e)
	277	goto cleanup;
	278
	279	if (BN_num_bits(key->e) > 64)
	280	goto cleanup;
	281
	282	*e = BN_get_word(key->e);
	283
	284	if (BN_num_bits(key->e) < 33) {
	285	ret = 0;
	286	goto cleanup;
	287	}
	288
	289	bn_te = BN_dup(key->e);
	290	if (!bn_te)
	291	goto cleanup;
	292
	293	if (!BN_rshift(bn_te, bn_te, 32))
	294	goto cleanup;
	295
	296	if (!BN_mask_bits(bn_te, 32))
	297	goto cleanup;
	298
	299	te = BN_get_word(bn_te);
	300	te <<= 32;
	301	*e \|= te;
	302	ret = 0;
	303
	304	cleanup:
	305	if (bn_te)
	306	BN_free(bn_te);
	307
	308	return ret;
	309	}
	310
19c402af SG	311	/*
	312	* rsa_get_params(): - Get the important parameters of an RSA public key
	313	*/
e0f2f155 MW	314	int rsa_get_params(RSA key, uint64_t exponent, uint32_t *n0_invp,
e0f2f155 MW	315	BIGNUM modulusp, BIGNUM r_squaredp)
19c402af SG	316	{
	317	BIGNUM big1, big2, big32, big2_32;
	318	BIGNUM n, r, r_squared, tmp;
	319	BN_CTX *bn_ctx = BN_CTX_new();
	320	int ret = 0;
	321
	322	/* Initialize BIGNUMs */
	323	big1 = BN_new();
	324	big2 = BN_new();
	325	big32 = BN_new();
	326	r = BN_new();
	327	r_squared = BN_new();
	328	tmp = BN_new();
	329	big2_32 = BN_new();
	330	n = BN_new();
	331	if (!big1 \|\| !big2 \|\| !big32 \|\| !r \|\| !r_squared \|\| !tmp \|\| !big2_32 \|\|
	332	!n) {
	333	fprintf(stderr, "Out of memory (bignum)\n");
	334	return -ENOMEM;
	335	}
	336
e0f2f155 MW	337	if (0 != rsa_get_exponent(key, exponent))
	338	ret = -1;
	339
19c402af SG	340	if (!BN_copy(n, key->n) \|\| !BN_set_word(big1, 1L) \|\|
	341	!BN_set_word(big2, 2L) \|\| !BN_set_word(big32, 32L))
	342	ret = -1;
	343
	344	/* big2_32 = 2^32 */
	345	if (!BN_exp(big2_32, big2, big32, bn_ctx))
	346	ret = -1;
	347
	348	/* Calculate n0_inv = -1 / n[0] mod 2^32 */
	349	if (!BN_mod_inverse(tmp, n, big2_32, bn_ctx) \|\|
	350	!BN_sub(tmp, big2_32, tmp))
	351	ret = -1;
	352	*n0_invp = BN_get_word(tmp);
	353
	354	/* Calculate R = 2^(# of key bits) */
	355	if (!BN_set_word(tmp, BN_num_bits(n)) \|\|
	356	!BN_exp(r, big2, tmp, bn_ctx))
	357	ret = -1;
	358
	359	/* Calculate r_squared = R^2 mod n */
	360	if (!BN_copy(r_squared, r) \|\|
	361	!BN_mul(tmp, r_squared, r, bn_ctx) \|\|
	362	!BN_mod(r_squared, tmp, n, bn_ctx))
	363	ret = -1;
	364
	365	*modulusp = n;
	366	*r_squaredp = r_squared;
	367
	368	BN_free(big1);
	369	BN_free(big2);
	370	BN_free(big32);
	371	BN_free(r);
	372	BN_free(tmp);
	373	BN_free(big2_32);
	374	if (ret) {
	375	fprintf(stderr, "Bignum operations failed\n");
	376	return -ENOMEM;
	377	}
	378
	379	return ret;
	380	}
	381
	382	static int fdt_add_bignum(void blob, int noffset, const char prop_name,
	383	BIGNUM *num, int num_bits)
	384	{
	385	int nwords = num_bits / 32;
	386	int size;
	387	uint32_t buf, ptr;
	388	BIGNUM tmp, big2, big32, big2_32;
	389	BN_CTX *ctx;
	390	int ret;
	391
	392	tmp = BN_new();
	393	big2 = BN_new();
	394	big32 = BN_new();
	395	big2_32 = BN_new();
	396	if (!tmp \|\| !big2 \|\| !big32 \|\| !big2_32) {
	397	fprintf(stderr, "Out of memory (bignum)\n");
	398	return -ENOMEM;
	399	}
	400	ctx = BN_CTX_new();
	401	if (!tmp) {
	402	fprintf(stderr, "Out of memory (bignum context)\n");
	403	return -ENOMEM;
404	}
405	BN_set_word(big2, 2L);
406	BN_set_word(big32, 32L);
407	BN_exp(big2_32, big2, big32, ctx); /* B = 2^32 */
408
409	size = nwords * sizeof(uint32_t);
410	buf = malloc(size);
411	if (!buf) {
412	fprintf(stderr, "Out of memory (%d bytes)\n", size);
413	return -ENOMEM;
414	}
415
416	/* Write out modulus as big endian array of integers */
417	for (ptr = buf + nwords - 1; ptr >= buf; ptr--) {
418	BN_mod(tmp, num, big2_32, ctx); /* n = N mod B */
419	*ptr = cpu_to_fdt32(BN_get_word(tmp));
420	BN_rshift(num, num, 32); /* N = N/B */
421	}
422
713fb2dc	423	/*
	424	* We try signing with successively increasing size values, so this
	425	* might fail several times
	426	*/
19c402af	427	ret = fdt_setprop(blob, noffset, prop_name, buf, size);
2b9ec762	428	if (ret)
2b9ec762	429	return -FDT_ERR_NOSPACE;
19c402af SG	430	free(buf);
	431	BN_free(tmp);
	432	BN_free(big2);
	433	BN_free(big32);
	434	BN_free(big2_32);
	435
	436	return ret;
	437	}
	438
	439	int rsa_add_verify_data(struct image_sign_info info, void keydest)
	440	{
	441	BIGNUM modulus, r_squared;
e0f2f155	442	uint64_t exponent;
19c402af SG	443	uint32_t n0_inv;
	444	int parent, node;
	445	char name[100];
	446	int ret;
	447	int bits;
	448	RSA *rsa;
	449
	450	debug("%s: Getting verification data\n", __func__);
	451	ret = rsa_get_pub_key(info->keydir, info->keyname, &rsa);
	452	if (ret)
	453	return ret;
e0f2f155	454	ret = rsa_get_params(rsa, &exponent, &n0_inv, &modulus, &r_squared);
19c402af SG	455	if (ret)
	456	return ret;
	457	bits = BN_num_bits(modulus);
	458	parent = fdt_subnode_offset(keydest, 0, FIT_SIG_NODENAME);
	459	if (parent == -FDT_ERR_NOTFOUND) {
	460	parent = fdt_add_subnode(keydest, 0, FIT_SIG_NODENAME);
	461	if (parent < 0) {
597a8b2c SG	462	ret = parent;
	463	if (ret != -FDT_ERR_NOSPACE) {
	464	fprintf(stderr, "Couldn't create signature node: %s\n",
	465	fdt_strerror(parent));
	466	}
19c402af SG	467	}
19c402af SG	468	}
597a8b2c SG	469	if (ret)
597a8b2c SG	470	goto done;
19c402af SG	471
	472	/* Either create or overwrite the named key node */
	473	snprintf(name, sizeof(name), "key-%s", info->keyname);
	474	node = fdt_subnode_offset(keydest, parent, name);
	475	if (node == -FDT_ERR_NOTFOUND) {
	476	node = fdt_add_subnode(keydest, parent, name);
	477	if (node < 0) {
597a8b2c SG	478	ret = node;
	479	if (ret != -FDT_ERR_NOSPACE) {
	480	fprintf(stderr, "Could not create key subnode: %s\n",
	481	fdt_strerror(node));
	482	}
19c402af SG	483	}
	484	} else if (node < 0) {
	485	fprintf(stderr, "Cannot select keys parent: %s\n",
	486	fdt_strerror(node));
597a8b2c	487	ret = node;
19c402af SG	488	}
19c402af SG	489
597a8b2c SG	490	if (!ret) {
597a8b2c SG	491	ret = fdt_setprop_string(keydest, node, "key-name-hint",
19c402af	492	info->keyname);
597a8b2c	493	}
4f427a42 SG	494	if (!ret)
	495	ret = fdt_setprop_u32(keydest, node, "rsa,num-bits", bits);
	496	if (!ret)
	497	ret = fdt_setprop_u32(keydest, node, "rsa,n0-inverse", n0_inv);
e0f2f155 MW	498	if (!ret) {
	499	ret = fdt_setprop_u64(keydest, node, "rsa,exponent", exponent);
	500	}
4f427a42 SG	501	if (!ret) {
	502	ret = fdt_add_bignum(keydest, node, "rsa,modulus", modulus,
	503	bits);
	504	}
	505	if (!ret) {
	506	ret = fdt_add_bignum(keydest, node, "rsa,r-squared", r_squared,
	507	bits);
	508	}
	509	if (!ret) {
	510	ret = fdt_setprop_string(keydest, node, FIT_ALGO_PROP,
	511	info->algo->name);
	512	}
2b9ec762	513	if (!ret && info->require_keys) {
4f427a42 SG	514	ret = fdt_setprop_string(keydest, node, "required",
4f427a42 SG	515	info->require_keys);
19c402af	516	}
597a8b2c	517	done:
19c402af SG	518	BN_free(modulus);
	519	BN_free(r_squared);
	520	if (ret)
597a8b2c	521	return ret == -FDT_ERR_NOSPACE ? -ENOSPC : -EIO;
19c402af SG	522
	523	return 0;
	524	}