lib/rsa/rsa-verify.c - github/trini/u-boot - Gitiles

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

 #ifndef USE_HOSTCC
 #include <common.h>
 #include <fdtdec.h>
 #include <asm/types.h>
 #include <asm/byteorder.h>
 #include <asm/errno.h>
 #include <asm/types.h>
 #include <asm/unaligned.h>
 #else
 #include "fdt_host.h"
 #include "mkimage.h"
 #include <fdt_support.h>
 #endif
 #include <u-boot/rsa.h>
 #include <u-boot/sha1.h>
 #include <u-boot/sha256.h>

 #define UINT64_MULT32(v, multby)  (((uint64_t)(v)) * ((uint32_t)(multby)))

 #define get_unaligned_be32(a) fdt32_to_cpu(*(uint32_t *)a)
 #define put_unaligned_be32(a, b) (*(uint32_t *)(b) = cpu_to_fdt32(a))

 /**
  * subtract_modulus() - subtract modulus from the given value
  *
  * @key:	Key containing modulus to subtract
  * @num:	Number to subtract modulus from, as little endian word array
  */
 static void subtract_modulus(const struct rsa_public_key *key, uint32_t num[])
 {
 	int64_t acc = 0;
 	uint i;

 	for (i = 0; i < key->len; i++) {
 		acc += (uint64_t)num[i] - key->modulus[i];
 		num[i] = (uint32_t)acc;
 		acc >>= 32;
 	}
 }

 /**
  * greater_equal_modulus() - check if a value is >= modulus
  *
  * @key:	Key containing modulus to check
  * @num:	Number to check against modulus, as little endian word array
  * @return 0 if num < modulus, 1 if num >= modulus
  */
 static int greater_equal_modulus(const struct rsa_public_key *key,
 				 uint32_t num[])
 {
 	uint32_t i;

 	for (i = key->len - 1; i >= 0; i--) {
 		if (num[i] < key->modulus[i])
 			return 0;
 		if (num[i] > key->modulus[i])
 			return 1;
 	}

 	return 1;  /* equal */
 }

 /**
  * montgomery_mul_add_step() - Perform montgomery multiply-add step
  *
  * Operation: montgomery result[] += a * b[] / n0inv % modulus
  *
  * @key:	RSA key
  * @result:	Place to put result, as little endian word array
  * @a:		Multiplier
  * @b:		Multiplicand, as little endian word array
  */
 static void montgomery_mul_add_step(const struct rsa_public_key *key,
 		uint32_t result[], const uint32_t a, const uint32_t b[])
 {
 	uint64_t acc_a, acc_b;
 	uint32_t d0;
 	uint i;

 	acc_a = (uint64_t)a * b[0] + result[0];
 	d0 = (uint32_t)acc_a * key->n0inv;
 	acc_b = (uint64_t)d0 * key->modulus[0] + (uint32_t)acc_a;
 	for (i = 1; i < key->len; i++) {
 		acc_a = (acc_a >> 32) + (uint64_t)a * b[i] + result[i];
 		acc_b = (acc_b >> 32) + (uint64_t)d0 * key->modulus[i] +
 				(uint32_t)acc_a;
 		result[i - 1] = (uint32_t)acc_b;
 	}

 	acc_a = (acc_a >> 32) + (acc_b >> 32);

 	result[i - 1] = (uint32_t)acc_a;

 	if (acc_a >> 32)
 		subtract_modulus(key, result);
 }

 /**
  * montgomery_mul() - Perform montgomery mutitply
  *
  * Operation: montgomery result[] = a[] * b[] / n0inv % modulus
  *
  * @key:	RSA key
  * @result:	Place to put result, as little endian word array
  * @a:		Multiplier, as little endian word array
  * @b:		Multiplicand, as little endian word array
  */
 static void montgomery_mul(const struct rsa_public_key *key,
 		uint32_t result[], uint32_t a[], const uint32_t b[])
 {
 	uint i;

 	for (i = 0; i < key->len; ++i)
 		result[i] = 0;
 	for (i = 0; i < key->len; ++i)
 		montgomery_mul_add_step(key, result, a[i], b);
 }

 /**
  * pow_mod() - in-place public exponentiation
  *
  * @key:	RSA key
  * @inout:	Big-endian word array containing value and result
  */
 static int pow_mod(const struct rsa_public_key *key, uint32_t *inout)
 {
 	uint32_t *result, *ptr;
 	uint i;

 	/* Sanity check for stack size - key->len is in 32-bit words */
 	if (key->len > RSA_MAX_KEY_BITS / 32) {
 		debug("RSA key words %u exceeds maximum %d\n", key->len,
 		      RSA_MAX_KEY_BITS / 32);
 		return -EINVAL;
 	}

 	uint32_t val[key->len], acc[key->len], tmp[key->len];
 	result = tmp;  /* Re-use location. */

 	/* Convert from big endian byte array to little endian word array. */
 	for (i = 0, ptr = inout + key->len - 1; i < key->len; i++, ptr--)
 		val[i] = get_unaligned_be32(ptr);

 	montgomery_mul(key, acc, val, key->rr);  /* axx = a * RR / R mod M */
 	for (i = 0; i < 16; i += 2) {
 		montgomery_mul(key, tmp, acc, acc); /* tmp = acc^2 / R mod M */
 		montgomery_mul(key, acc, tmp, tmp); /* acc = tmp^2 / R mod M */
 	}
 	montgomery_mul(key, result, acc, val);  /* result = XX * a / R mod M */

 	/* Make sure result < mod; result is at most 1x mod too large. */
 	if (greater_equal_modulus(key, result))
 		subtract_modulus(key, result);

 	/* Convert to bigendian byte array */
 	for (i = key->len - 1, ptr = inout; (int)i >= 0; i--, ptr++)
 		put_unaligned_be32(result[i], ptr);
 	return 0;
 }

 static int rsa_verify_key(const struct rsa_public_key *key, const uint8_t *sig,
 			  const uint32_t sig_len, const uint8_t *hash,
 			  struct checksum_algo *algo)
 {
 	const uint8_t *padding;
 	int pad_len;
 	int ret;

 	if (!key || !sig || !hash || !algo)
 		return -EIO;

 	if (sig_len != (key->len * sizeof(uint32_t))) {
 		debug("Signature is of incorrect length %d\n", sig_len);
 		return -EINVAL;
 	}

 	debug("Checksum algorithm: %s", algo->name);

 	/* Sanity check for stack size */
 	if (sig_len > RSA_MAX_SIG_BITS / 8) {
 		debug("Signature length %u exceeds maximum %d\n", sig_len,
 		      RSA_MAX_SIG_BITS / 8);
 		return -EINVAL;
 	}

 	uint32_t buf[sig_len / sizeof(uint32_t)];

 	memcpy(buf, sig, sig_len);

 	ret = pow_mod(key, buf);
 	if (ret)
 		return ret;

 	padding = algo->rsa_padding;
 	pad_len = algo->pad_len - algo->checksum_len;

 	/* Check pkcs1.5 padding bytes. */
 	if (memcmp(buf, padding, pad_len)) {
 		debug("In RSAVerify(): Padding check failed!\n");
 		return -EINVAL;
 	}

 	/* Check hash. */
 	if (memcmp((uint8_t *)buf + pad_len, hash, sig_len - pad_len)) {
 		debug("In RSAVerify(): Hash check failed!\n");
 		return -EACCES;
 	}

 	return 0;
 }

 static void rsa_convert_big_endian(uint32_t *dst, const uint32_t *src, int len)
 {
 	int i;

 	for (i = 0; i < len; i++)
 		dst[i] = fdt32_to_cpu(src[len - 1 - i]);
 }

 static int rsa_verify_with_keynode(struct image_sign_info *info,
 		const void *hash, uint8_t *sig, uint sig_len, int node)
 {
 	const void *blob = info->fdt_blob;
 	struct rsa_public_key key;
 	const void *modulus, *rr;
 	int ret;

 	if (node < 0) {
 		debug("%s: Skipping invalid node", __func__);
 		return -EBADF;
 	}
 	if (!fdt_getprop(blob, node, "rsa,n0-inverse", NULL)) {
 		debug("%s: Missing rsa,n0-inverse", __func__);
 		return -EFAULT;
 	}
 	key.len = fdtdec_get_int(blob, node, "rsa,num-bits", 0);
 	key.n0inv = fdtdec_get_int(blob, node, "rsa,n0-inverse", 0);
 	modulus = fdt_getprop(blob, node, "rsa,modulus", NULL);
 	rr = fdt_getprop(blob, node, "rsa,r-squared", NULL);
 	if (!key.len || !modulus || !rr) {
 		debug("%s: Missing RSA key info", __func__);
 		return -EFAULT;
 	}

 	/* Sanity check for stack size */
 	if (key.len > RSA_MAX_KEY_BITS || key.len < RSA_MIN_KEY_BITS) {
 		debug("RSA key bits %u outside allowed range %d..%d\n",
 		      key.len, RSA_MIN_KEY_BITS, RSA_MAX_KEY_BITS);
 		return -EFAULT;
 	}
 	key.len /= sizeof(uint32_t) * 8;
 	uint32_t key1[key.len], key2[key.len];

 	key.modulus = key1;
 	key.rr = key2;
 	rsa_convert_big_endian(key.modulus, modulus, key.len);
 	rsa_convert_big_endian(key.rr, rr, key.len);
 	if (!key.modulus || !key.rr) {
 		debug("%s: Out of memory", __func__);
 		return -ENOMEM;
 	}

 	debug("key length %d\n", key.len);
 	ret = rsa_verify_key(&key, sig, sig_len, hash, info->algo->checksum);
 	if (ret) {
 		printf("%s: RSA failed to verify: %d\n", __func__, ret);
 		return ret;
 	}

 	return 0;
 }

 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->algo->checksum->pad_len];
 	int ndepth, noffset;
 	int sig_node, node;
 	char name[100];
 	int ret;

 	/*
 	 * Verify that the checksum-length does not exceed the
 	 * rsa-signature-length
 	 */
 	if (info->algo->checksum->checksum_len >
 	    info->algo->checksum->pad_len) {
 		debug("%s: invlaid checksum-algorithm %s for %s\n",
 		      __func__, info->algo->checksum->name, info->algo->name);
 		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 */
 	info->algo->checksum->calculate(region, region_count, hash);

 	/* See if we must use a particular key */
 	if (info->required_keynode != -1) {
 		ret = rsa_verify_with_keynode(info, hash, sig, sig_len,
 			info->required_keynode);
 		if (!ret)
 			return ret;
 	}

 	/* Look for a key that matches our hint */
 	snprintf(name, sizeof(name), "key-%s", info->keyname);
 	node = fdt_subnode_offset(blob, sig_node, name);
 	ret = rsa_verify_with_keynode(info, hash, sig, sig_len, node);
 	if (!ret)
 		return ret;

 	/* No luck, so try each of the keys in turn */
 	for (ndepth = 0, noffset = fdt_next_node(info->fit, sig_node, &ndepth);
 			(noffset >= 0) && (ndepth > 0);
 			noffset = fdt_next_node(info->fit, noffset, &ndepth)) {
 		if (ndepth == 1 && noffset != node) {
 			ret = rsa_verify_with_keynode(info, hash, sig, sig_len,
 						      noffset);
 			if (!ret)
 				break;
 		}
 	}

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

	#ifndef USE_HOSTCC
	#include <common.h>
	#include <fdtdec.h>
	#include <asm/types.h>
	#include <asm/byteorder.h>
	#include <asm/errno.h>
	#include <asm/types.h>
	#include <asm/unaligned.h>
	#else
	#include "fdt_host.h"
	#include "mkimage.h"
	#include <fdt_support.h>
	#endif
	#include <u-boot/rsa.h>
	#include <u-boot/sha1.h>
	#include <u-boot/sha256.h>

	#define UINT64_MULT32(v, multby) (((uint64_t)(v)) * ((uint32_t)(multby)))

	#define get_unaligned_be32(a) fdt32_to_cpu((uint32_t )a)
	#define put_unaligned_be32(a, b) ((uint32_t )(b) = cpu_to_fdt32(a))

	/**
	* subtract_modulus() - subtract modulus from the given value
	*
	* @key: Key containing modulus to subtract
	* @num: Number to subtract modulus from, as little endian word array
	*/
	static void subtract_modulus(const struct rsa_public_key *key, uint32_t num[])
	{
	int64_t acc = 0;
	uint i;

	for (i = 0; i < key->len; i++) {
	acc += (uint64_t)num[i] - key->modulus[i];
	num[i] = (uint32_t)acc;
	acc >>= 32;
	}
	}

	/**
	* greater_equal_modulus() - check if a value is >= modulus
	*
	* @key: Key containing modulus to check
	* @num: Number to check against modulus, as little endian word array
	* @return 0 if num < modulus, 1 if num >= modulus
	*/
	static int greater_equal_modulus(const struct rsa_public_key *key,
	uint32_t num[])
	{
	uint32_t i;

	for (i = key->len - 1; i >= 0; i--) {
	if (num[i] < key->modulus[i])
	return 0;
	if (num[i] > key->modulus[i])
	return 1;
	}

	return 1; /* equal */
	}

	/**
	* montgomery_mul_add_step() - Perform montgomery multiply-add step
	*
	* Operation: montgomery result[] += a * b[] / n0inv % modulus
	*
	* @key: RSA key
	* @result: Place to put result, as little endian word array
	* @a: Multiplier
	* @b: Multiplicand, as little endian word array
	*/
	static void montgomery_mul_add_step(const struct rsa_public_key *key,
	uint32_t result[], const uint32_t a, const uint32_t b[])
	{
	uint64_t acc_a, acc_b;
	uint32_t d0;
	uint i;

	acc_a = (uint64_t)a * b[0] + result[0];
	d0 = (uint32_t)acc_a * key->n0inv;
	acc_b = (uint64_t)d0 * key->modulus[0] + (uint32_t)acc_a;
	for (i = 1; i < key->len; i++) {
	acc_a = (acc_a >> 32) + (uint64_t)a * b[i] + result[i];
	acc_b = (acc_b >> 32) + (uint64_t)d0 * key->modulus[i] +
	(uint32_t)acc_a;
	result[i - 1] = (uint32_t)acc_b;
	}

	acc_a = (acc_a >> 32) + (acc_b >> 32);

	result[i - 1] = (uint32_t)acc_a;

	if (acc_a >> 32)
	subtract_modulus(key, result);
	}

	/**
	* montgomery_mul() - Perform montgomery mutitply
	*
	* Operation: montgomery result[] = a[] * b[] / n0inv % modulus
	*
	* @key: RSA key
	* @result: Place to put result, as little endian word array
	* @a: Multiplier, as little endian word array
	* @b: Multiplicand, as little endian word array
	*/
	static void montgomery_mul(const struct rsa_public_key *key,
	uint32_t result[], uint32_t a[], const uint32_t b[])
	{
	uint i;

	for (i = 0; i < key->len; ++i)
	result[i] = 0;
	for (i = 0; i < key->len; ++i)
	montgomery_mul_add_step(key, result, a[i], b);
	}

	/**
	* pow_mod() - in-place public exponentiation
	*
	* @key: RSA key
	* @inout: Big-endian word array containing value and result
	*/
	static int pow_mod(const struct rsa_public_key key, uint32_t inout)
	{
	uint32_t result, ptr;
	uint i;

	/* Sanity check for stack size - key->len is in 32-bit words */
	if (key->len > RSA_MAX_KEY_BITS / 32) {
	debug("RSA key words %u exceeds maximum %d\n", key->len,
	RSA_MAX_KEY_BITS / 32);
	return -EINVAL;
	}

	uint32_t val[key->len], acc[key->len], tmp[key->len];
	result = tmp; /* Re-use location. */

	/* Convert from big endian byte array to little endian word array. */
	for (i = 0, ptr = inout + key->len - 1; i < key->len; i++, ptr--)
	val[i] = get_unaligned_be32(ptr);

	montgomery_mul(key, acc, val, key->rr); /* axx = a * RR / R mod M */
	for (i = 0; i < 16; i += 2) {
	montgomery_mul(key, tmp, acc, acc); /* tmp = acc^2 / R mod M */
	montgomery_mul(key, acc, tmp, tmp); /* acc = tmp^2 / R mod M */
	}
	montgomery_mul(key, result, acc, val); /* result = XX * a / R mod M */

	/* Make sure result < mod; result is at most 1x mod too large. */
	if (greater_equal_modulus(key, result))
	subtract_modulus(key, result);

	/* Convert to bigendian byte array */
	for (i = key->len - 1, ptr = inout; (int)i >= 0; i--, ptr++)
	put_unaligned_be32(result[i], ptr);
	return 0;
	}

	static int rsa_verify_key(const struct rsa_public_key key, const uint8_t sig,
	const uint32_t sig_len, const uint8_t *hash,
	struct checksum_algo *algo)
	{
	const uint8_t *padding;
	int pad_len;
	int ret;

	if (!key \|\| !sig \|\| !hash \|\| !algo)
	return -EIO;

	if (sig_len != (key->len * sizeof(uint32_t))) {
	debug("Signature is of incorrect length %d\n", sig_len);
	return -EINVAL;
	}

	debug("Checksum algorithm: %s", algo->name);

	/* Sanity check for stack size */
	if (sig_len > RSA_MAX_SIG_BITS / 8) {
	debug("Signature length %u exceeds maximum %d\n", sig_len,
	RSA_MAX_SIG_BITS / 8);
	return -EINVAL;
	}

	uint32_t buf[sig_len / sizeof(uint32_t)];

	memcpy(buf, sig, sig_len);

	ret = pow_mod(key, buf);
	if (ret)
	return ret;

	padding = algo->rsa_padding;
	pad_len = algo->pad_len - algo->checksum_len;

	/* Check pkcs1.5 padding bytes. */
	if (memcmp(buf, padding, pad_len)) {
	debug("In RSAVerify(): Padding check failed!\n");
	return -EINVAL;
	}

	/* Check hash. */
	if (memcmp((uint8_t *)buf + pad_len, hash, sig_len - pad_len)) {
	debug("In RSAVerify(): Hash check failed!\n");
	return -EACCES;
	}

	return 0;
	}

	static void rsa_convert_big_endian(uint32_t dst, const uint32_t src, int len)
	{
	int i;

	for (i = 0; i < len; i++)
	dst[i] = fdt32_to_cpu(src[len - 1 - i]);
	}

	static int rsa_verify_with_keynode(struct image_sign_info *info,
	const void hash, uint8_t sig, uint sig_len, int node)
	{
	const void *blob = info->fdt_blob;
	struct rsa_public_key key;
	const void modulus, rr;
	int ret;

	if (node < 0) {
	debug("%s: Skipping invalid node", __func__);
	return -EBADF;
	}
	if (!fdt_getprop(blob, node, "rsa,n0-inverse", NULL)) {
	debug("%s: Missing rsa,n0-inverse", __func__);
	return -EFAULT;
	}
	key.len = fdtdec_get_int(blob, node, "rsa,num-bits", 0);
	key.n0inv = fdtdec_get_int(blob, node, "rsa,n0-inverse", 0);
	modulus = fdt_getprop(blob, node, "rsa,modulus", NULL);
	rr = fdt_getprop(blob, node, "rsa,r-squared", NULL);
	if (!key.len \|\| !modulus \|\| !rr) {
	debug("%s: Missing RSA key info", __func__);
	return -EFAULT;
	}

	/* Sanity check for stack size */
	if (key.len > RSA_MAX_KEY_BITS \|\| key.len < RSA_MIN_KEY_BITS) {
	debug("RSA key bits %u outside allowed range %d..%d\n",
	key.len, RSA_MIN_KEY_BITS, RSA_MAX_KEY_BITS);
	return -EFAULT;
	}
	key.len /= sizeof(uint32_t) * 8;
	uint32_t key1[key.len], key2[key.len];

	key.modulus = key1;
	key.rr = key2;
	rsa_convert_big_endian(key.modulus, modulus, key.len);
	rsa_convert_big_endian(key.rr, rr, key.len);
	if (!key.modulus \|\| !key.rr) {
	debug("%s: Out of memory", __func__);
	return -ENOMEM;
	}

	debug("key length %d\n", key.len);
	ret = rsa_verify_key(&key, sig, sig_len, hash, info->algo->checksum);
	if (ret) {
	printf("%s: RSA failed to verify: %d\n", __func__, ret);
	return ret;
	}

	return 0;
	}

	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->algo->checksum->pad_len];
	int ndepth, noffset;
	int sig_node, node;
	char name[100];
	int ret;

	/*
	* Verify that the checksum-length does not exceed the
	* rsa-signature-length
	*/
	if (info->algo->checksum->checksum_len >
	info->algo->checksum->pad_len) {
	debug("%s: invlaid checksum-algorithm %s for %s\n",
	__func__, info->algo->checksum->name, info->algo->name);
	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 */
	info->algo->checksum->calculate(region, region_count, hash);

	/* See if we must use a particular key */
	if (info->required_keynode != -1) {
	ret = rsa_verify_with_keynode(info, hash, sig, sig_len,
	info->required_keynode);
	if (!ret)
	return ret;
	}

	/* Look for a key that matches our hint */
	snprintf(name, sizeof(name), "key-%s", info->keyname);
	node = fdt_subnode_offset(blob, sig_node, name);
	ret = rsa_verify_with_keynode(info, hash, sig, sig_len, node);
	if (!ret)
	return ret;

	/* No luck, so try each of the keys in turn */
	for (ndepth = 0, noffset = fdt_next_node(info->fit, sig_node, &ndepth);
	(noffset >= 0) && (ndepth > 0);
	noffset = fdt_next_node(info->fit, noffset, &ndepth)) {
	if (ndepth == 1 && noffset != node) {
	ret = rsa_verify_with_keynode(info, hash, sig, sig_len,
	noffset);
	if (!ret)
	break;
	}
	}

	return ret;
	}