common/image-sig.c - github/trini/u-boot - Gitiles

 /*
  * Copyright (c) 2013, Google Inc.
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License as
  * published by the Free Software Foundation; either version 2 of
  * the License, or (at your option) any later version.
  *
  * This program is distributed in the hope that 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.
  *
  * You should have received a copy of the GNU General Public License
  * along with this program; if not, write to the Free Software
  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  * MA 02111-1307 USA
  */

 #ifdef USE_HOSTCC
 #include "mkimage.h"
 #include <time.h>
 #else
 #include <common.h>
 #include <malloc.h>
 DECLARE_GLOBAL_DATA_PTR;
 #endif /* !USE_HOSTCC*/
 #include <image.h>
 #include <rsa.h>

 #define IMAGE_MAX_HASHED_NODES		100

 struct image_sig_algo image_sig_algos[] = {
 	{
 		"sha1,rsa2048",
 		rsa_sign,
 		rsa_add_verify_data,
 		rsa_verify,
 	}
 };

 struct image_sig_algo *image_get_sig_algo(const char *name)
 {
 	int i;

 	for (i = 0; i < ARRAY_SIZE(image_sig_algos); i++) {
 		if (!strcmp(image_sig_algos[i].name, name))
 			return &image_sig_algos[i];
 	}

 	return NULL;
 }

 /**
  * fit_region_make_list() - Make a list of image regions
  *
  * Given a list of fdt_regions, create a list of image_regions. This is a
  * simple conversion routine since the FDT and image code use different
  * structures.
  *
  * @fit: FIT image
  * @fdt_regions: Pointer to FDT regions
  * @count: Number of FDT regions
  * @region: Pointer to image regions, which must hold @count records. If
  * region is NULL, then (except for an SPL build) the array will be
  * allocated.
  * @return: Pointer to image regions
  */
 struct image_region *fit_region_make_list(const void *fit,
 		struct fdt_region *fdt_regions, int count,
 		struct image_region *region)
 {
 	int i;

 	debug("Hash regions:\n");
 	debug("%10s %10s\n", "Offset", "Size");

 	/*
 	 * Use malloc() except in SPL (to save code size). In SPL the caller
 	 * must allocate the array.
 	 */
 #ifndef CONFIG_SPL_BUILD
 	if (!region)
 		region = calloc(sizeof(*region), count);
 #endif
 	if (!region)
 		return NULL;
 	for (i = 0; i < count; i++) {
 		debug("%10x %10x\n", fdt_regions[i].offset,
 		      fdt_regions[i].size);
 		region[i].data = fit + fdt_regions[i].offset;
 		region[i].size = fdt_regions[i].size;
 	}

 	return region;
 }

 static int fit_image_setup_verify(struct image_sign_info *info,
 		const void *fit, int noffset, int required_keynode,
 		char **err_msgp)
 {
 	char *algo_name;

 	if (fit_image_hash_get_algo(fit, noffset, &algo_name)) {
 		*err_msgp = "Can't get hash algo property";
 		return -1;
 	}
 	memset(info, '\0', sizeof(*info));
 	info->keyname = fdt_getprop(fit, noffset, "key-name-hint", NULL);
 	info->fit = (void *)fit;
 	info->node_offset = noffset;
 	info->algo = image_get_sig_algo(algo_name);
 	info->fdt_blob = gd_fdt_blob();
 	info->required_keynode = required_keynode;
 	printf("%s:%s", algo_name, info->keyname);

 	if (!info->algo) {
 		*err_msgp = "Unknown signature algorithm";
 		return -1;
 	}

 	return 0;
 }

 int fit_image_check_sig(const void *fit, int noffset, const void *data,
 		size_t size, int required_keynode, char **err_msgp)
 {
 	struct image_sign_info info;
 	struct image_region region;
 	uint8_t *fit_value;
 	int fit_value_len;

 	*err_msgp = NULL;
 	if (fit_image_setup_verify(&info, fit, noffset, required_keynode,
 				   err_msgp))
 		return -1;

 	if (fit_image_hash_get_value(fit, noffset, &fit_value,
 				     &fit_value_len)) {
 		*err_msgp = "Can't get hash value property";
 		return -1;
 	}

 	region.data = data;
 	region.size = size;

 	if (info.algo->verify(&info, &region, 1, fit_value, fit_value_len)) {
 		*err_msgp = "Verification failed";
 		return -1;
 	}

 	return 0;
 }

 static int fit_image_verify_sig(const void *fit, int image_noffset,
 		const char *data, size_t size, const void *sig_blob,
 		int sig_offset)
 {
 	int noffset;
 	char *err_msg = "";
 	int verified = 0;
 	int ret;

 	/* Process all hash subnodes of the component image node */
 	for (noffset = fdt_first_subnode(fit, image_noffset);
 	     noffset >= 0;
 	     noffset = fdt_next_subnode(fit, noffset)) {
 		const char *name = fit_get_name(fit, noffset, NULL);

 		if (!strncmp(name, FIT_SIG_NODENAME,
 			     strlen(FIT_SIG_NODENAME))) {
 			ret = fit_image_check_sig(fit, noffset, data,
 							size, -1, &err_msg);
 			if (ret) {
 				puts("- ");
 			} else {
 				puts("+ ");
 				verified = 1;
 				break;
 			}
 		}
 	}

 	if (noffset == -FDT_ERR_TRUNCATED || noffset == -FDT_ERR_BADSTRUCTURE) {
 		err_msg = "Corrupted or truncated tree";
 		goto error;
 	}

 	return verified ? 0 : -EPERM;

 error:
 	printf(" error!\n%s for '%s' hash node in '%s' image node\n",
 	       err_msg, fit_get_name(fit, noffset, NULL),
 	       fit_get_name(fit, image_noffset, NULL));
 	return -1;
 }

 int fit_image_verify_required_sigs(const void *fit, int image_noffset,
 		const char *data, size_t size, const void *sig_blob,
 		int *no_sigsp)
 {
 	int verify_count = 0;
 	int noffset;
 	int sig_node;

 	/* Work out what we need to verify */
 	*no_sigsp = 1;
 	sig_node = fdt_subnode_offset(sig_blob, 0, FIT_SIG_NODENAME);
 	if (sig_node < 0) {
 		debug("%s: No signature node found: %s\n", __func__,
 		      fdt_strerror(sig_node));
 		return 0;
 	}

 	for (noffset = fdt_first_subnode(sig_blob, sig_node);
 	     noffset >= 0;
 	     noffset = fdt_next_subnode(sig_blob, noffset)) {
 		const char *required;
 		int ret;

 		required = fdt_getprop(sig_blob, noffset, "required", NULL);
 		if (!required || strcmp(required, "image"))
 			continue;
 		ret = fit_image_verify_sig(fit, image_noffset, data, size,
 					sig_blob, noffset);
 		if (ret) {
 			printf("Failed to verify required signature '%s'\n",
 			       fit_get_name(sig_blob, noffset, NULL));
 			return ret;
 		}
 		verify_count++;
 	}

 	if (verify_count)
 		*no_sigsp = 0;

 	return 0;
 }

 int fit_config_check_sig(const void *fit, int noffset, int required_keynode,
 			 char **err_msgp)
 {
 	char * const exc_prop[] = {"data"};
 	const char *prop, *end, *name;
 	struct image_sign_info info;
 	const uint32_t *strings;
 	uint8_t *fit_value;
 	int fit_value_len;
 	int max_regions;
 	int i, prop_len;
 	char path[200];
 	int count;

 	debug("%s: fdt=%p, conf='%s', sig='%s'\n", __func__, gd_fdt_blob(),
 	      fit_get_name(fit, noffset, NULL),
 	      fit_get_name(gd_fdt_blob(), required_keynode, NULL));
 	*err_msgp = NULL;
 	if (fit_image_setup_verify(&info, fit, noffset, required_keynode,
 				   err_msgp))
 		return -1;

 	if (fit_image_hash_get_value(fit, noffset, &fit_value,
 				     &fit_value_len)) {
 		*err_msgp = "Can't get hash value property";
 		return -1;
 	}

 	/* Count the number of strings in the property */
 	prop = fdt_getprop(fit, noffset, "hashed-nodes", &prop_len);
 	end = prop ? prop + prop_len : prop;
 	for (name = prop, count = 0; name < end; name++)
 		if (!*name)
 			count++;
 	if (!count) {
 		*err_msgp = "Can't get hashed-nodes property";
 		return -1;
 	}

 	/* Add a sanity check here since we are using the stack */
 	if (count > IMAGE_MAX_HASHED_NODES) {
 		*err_msgp = "Number of hashed nodes exceeds maximum";
 		return -1;
 	}

 	/* Create a list of node names from those strings */
 	char *node_inc[count];

 	debug("Hash nodes (%d):\n", count);
 	for (name = prop, i = 0; name < end; name += strlen(name) + 1, i++) {
 		debug("   '%s'\n", name);
 		node_inc[i] = (char *)name;
 	}

 	/*
 	 * Each node can generate one region for each sub-node. Allow for
 	 * 7 sub-nodes (hash@1, signature@1, etc.) and some extra.
 	 */
 	max_regions = 20 + count * 7;
 	struct fdt_region fdt_regions[max_regions];

 	/* Get a list of regions to hash */
 	count = fdt_find_regions(fit, node_inc, count,
 			exc_prop, ARRAY_SIZE(exc_prop),
 			fdt_regions, max_regions - 1,
 			path, sizeof(path), 0);
 	if (count < 0) {
 		*err_msgp = "Failed to hash configuration";
 		return -1;
 	}
 	if (count == 0) {
 		*err_msgp = "No data to hash";
 		return -1;
 	}
 	if (count >= max_regions - 1) {
 		*err_msgp = "Too many hash regions";
 		return -1;
 	}

 	/* Add the strings */
 	strings = fdt_getprop(fit, noffset, "hashed-strings", NULL);
 	if (strings) {
 		fdt_regions[count].offset = fdt_off_dt_strings(fit) +
 				fdt32_to_cpu(strings[0]);
 		fdt_regions[count].size = fdt32_to_cpu(strings[1]);
 		count++;
 	}

 	/* Allocate the region list on the stack */
 	struct image_region region[count];

 	fit_region_make_list(fit, fdt_regions, count, region);
 	if (info.algo->verify(&info, region, count, fit_value,
 			      fit_value_len)) {
 		*err_msgp = "Verification failed";
 		return -1;
 	}

 	return 0;
 }

 static int fit_config_verify_sig(const void *fit, int conf_noffset,
 		const void *sig_blob, int sig_offset)
 {
 	int noffset;
 	char *err_msg = "";
 	int verified = 0;
 	int ret;

 	/* Process all hash subnodes of the component conf node */
 	for (noffset = fdt_first_subnode(fit, conf_noffset);
 	     noffset >= 0;
 	     noffset = fdt_next_subnode(fit, noffset)) {
 		const char *name = fit_get_name(fit, noffset, NULL);

 		if (!strncmp(name, FIT_SIG_NODENAME,
 			     strlen(FIT_SIG_NODENAME))) {
 			ret = fit_config_check_sig(fit, noffset, sig_offset,
 						   &err_msg);
 			if (ret) {
 				puts("- ");
 			} else {
 				puts("+ ");
 				verified = 1;
 				break;
 			}
 		}
 	}

 	if (noffset == -FDT_ERR_TRUNCATED || noffset == -FDT_ERR_BADSTRUCTURE) {
 		err_msg = "Corrupted or truncated tree";
 		goto error;
 	}

 	return verified ? 0 : -EPERM;

 error:
 	printf(" error!\n%s for '%s' hash node in '%s' config node\n",
 	       err_msg, fit_get_name(fit, noffset, NULL),
 	       fit_get_name(fit, conf_noffset, NULL));
 	return -1;
 }

 int fit_config_verify_required_sigs(const void *fit, int conf_noffset,
 		const void *sig_blob)
 {
 	int noffset;
 	int sig_node;

 	/* Work out what we need to verify */
 	sig_node = fdt_subnode_offset(sig_blob, 0, FIT_SIG_NODENAME);
 	if (sig_node < 0) {
 		debug("%s: No signature node found: %s\n", __func__,
 		      fdt_strerror(sig_node));
 		return 0;
 	}

 	for (noffset = fdt_first_subnode(sig_blob, sig_node);
 	     noffset >= 0;
 	     noffset = fdt_next_subnode(sig_blob, noffset)) {
 		const char *required;
 		int ret;

 		required = fdt_getprop(sig_blob, noffset, "required", NULL);
 		if (!required || strcmp(required, "conf"))
 			continue;
 		ret = fit_config_verify_sig(fit, conf_noffset, sig_blob,
 					    noffset);
 		if (ret) {
 			printf("Failed to verify required signature '%s'\n",
 			       fit_get_name(sig_blob, noffset, NULL));
 			return ret;
 		}
 	}

 	return 0;
 }

 int fit_config_verify(const void *fit, int conf_noffset)
 {
 	return !fit_config_verify_required_sigs(fit, conf_noffset,
 						gd_fdt_blob());
 }
	/*
	* Copyright (c) 2013, Google Inc.
	*
	* This program is free software; you can redistribute it and/or
	* modify it under the terms of the GNU General Public License as
	* published by the Free Software Foundation; either version 2 of
	* the License, or (at your option) any later version.
	*
	* This program is distributed in the hope that 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.
	*
	* You should have received a copy of the GNU General Public License
	* along with this program; if not, write to the Free Software
	* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
	* MA 02111-1307 USA
	*/

	#ifdef USE_HOSTCC
	#include "mkimage.h"
	#include <time.h>
	#else
	#include <common.h>
	#include <malloc.h>
	DECLARE_GLOBAL_DATA_PTR;
	#endif /* !USE_HOSTCC*/
	#include <image.h>
	#include <rsa.h>

	#define IMAGE_MAX_HASHED_NODES 100

	struct image_sig_algo image_sig_algos[] = {
	{
	"sha1,rsa2048",
	rsa_sign,
	rsa_add_verify_data,
	rsa_verify,
	}
	};

	struct image_sig_algo image_get_sig_algo(const char name)
	{
	int i;

	for (i = 0; i < ARRAY_SIZE(image_sig_algos); i++) {
	if (!strcmp(image_sig_algos[i].name, name))
	return &image_sig_algos[i];
	}

	return NULL;
	}

	/**
	* fit_region_make_list() - Make a list of image regions
	*
	* Given a list of fdt_regions, create a list of image_regions. This is a
	* simple conversion routine since the FDT and image code use different
	* structures.
	*
	* @fit: FIT image
	* @fdt_regions: Pointer to FDT regions
	* @count: Number of FDT regions
	* @region: Pointer to image regions, which must hold @count records. If
	* region is NULL, then (except for an SPL build) the array will be
	* allocated.
	* @return: Pointer to image regions
	*/
	struct image_region fit_region_make_list(const void fit,
	struct fdt_region *fdt_regions, int count,
	struct image_region *region)
	{
	int i;

	debug("Hash regions:\n");
	debug("%10s %10s\n", "Offset", "Size");

	/*
	* Use malloc() except in SPL (to save code size). In SPL the caller
	* must allocate the array.
	*/
	#ifndef CONFIG_SPL_BUILD
	if (!region)
	region = calloc(sizeof(*region), count);
	#endif
	if (!region)
	return NULL;
	for (i = 0; i < count; i++) {
	debug("%10x %10x\n", fdt_regions[i].offset,
	fdt_regions[i].size);
	region[i].data = fit + fdt_regions[i].offset;
	region[i].size = fdt_regions[i].size;
	}

	return region;
	}

	static int fit_image_setup_verify(struct image_sign_info *info,
	const void *fit, int noffset, int required_keynode,
	char **err_msgp)
	{
	char *algo_name;

	if (fit_image_hash_get_algo(fit, noffset, &algo_name)) {
	*err_msgp = "Can't get hash algo property";
	return -1;
	}
	memset(info, '\0', sizeof(*info));
	info->keyname = fdt_getprop(fit, noffset, "key-name-hint", NULL);
	info->fit = (void *)fit;
	info->node_offset = noffset;
	info->algo = image_get_sig_algo(algo_name);
	info->fdt_blob = gd_fdt_blob();
	info->required_keynode = required_keynode;
	printf("%s:%s", algo_name, info->keyname);

	if (!info->algo) {
	*err_msgp = "Unknown signature algorithm";
	return -1;
	}

	return 0;
	}

	int fit_image_check_sig(const void fit, int noffset, const void data,
	size_t size, int required_keynode, char **err_msgp)
	{
	struct image_sign_info info;
	struct image_region region;
	uint8_t *fit_value;
	int fit_value_len;

	*err_msgp = NULL;
	if (fit_image_setup_verify(&info, fit, noffset, required_keynode,
	err_msgp))
	return -1;

	if (fit_image_hash_get_value(fit, noffset, &fit_value,
	&fit_value_len)) {
	*err_msgp = "Can't get hash value property";
	return -1;
	}

	region.data = data;
	region.size = size;

	if (info.algo->verify(&info, &region, 1, fit_value, fit_value_len)) {
	*err_msgp = "Verification failed";
	return -1;
	}

	return 0;
	}

	static int fit_image_verify_sig(const void *fit, int image_noffset,
	const char data, size_t size, const void sig_blob,
	int sig_offset)
	{
	int noffset;
	char *err_msg = "";
	int verified = 0;
	int ret;

	/* Process all hash subnodes of the component image node */
	for (noffset = fdt_first_subnode(fit, image_noffset);
	noffset >= 0;
	noffset = fdt_next_subnode(fit, noffset)) {
	const char *name = fit_get_name(fit, noffset, NULL);

	if (!strncmp(name, FIT_SIG_NODENAME,
	strlen(FIT_SIG_NODENAME))) {
	ret = fit_image_check_sig(fit, noffset, data,
	size, -1, &err_msg);
	if (ret) {
	puts("- ");
	} else {
	puts("+ ");
	verified = 1;
	break;
	}
	}
	}

	if (noffset == -FDT_ERR_TRUNCATED \|\| noffset == -FDT_ERR_BADSTRUCTURE) {
	err_msg = "Corrupted or truncated tree";
	goto error;
	}

	return verified ? 0 : -EPERM;

	error:
	printf(" error!\n%s for '%s' hash node in '%s' image node\n",
	err_msg, fit_get_name(fit, noffset, NULL),
	fit_get_name(fit, image_noffset, NULL));
	return -1;
	}

	int fit_image_verify_required_sigs(const void *fit, int image_noffset,
	const char data, size_t size, const void sig_blob,
	int *no_sigsp)
	{
	int verify_count = 0;
	int noffset;
	int sig_node;

	/* Work out what we need to verify */
	*no_sigsp = 1;
	sig_node = fdt_subnode_offset(sig_blob, 0, FIT_SIG_NODENAME);
	if (sig_node < 0) {
	debug("%s: No signature node found: %s\n", __func__,
	fdt_strerror(sig_node));
	return 0;
	}

	for (noffset = fdt_first_subnode(sig_blob, sig_node);
	noffset >= 0;
	noffset = fdt_next_subnode(sig_blob, noffset)) {
	const char *required;
	int ret;

	required = fdt_getprop(sig_blob, noffset, "required", NULL);
	if (!required \|\| strcmp(required, "image"))
	continue;
	ret = fit_image_verify_sig(fit, image_noffset, data, size,
	sig_blob, noffset);
	if (ret) {
	printf("Failed to verify required signature '%s'\n",
	fit_get_name(sig_blob, noffset, NULL));
	return ret;
	}
	verify_count++;
	}

	if (verify_count)
	*no_sigsp = 0;

	return 0;
	}

	int fit_config_check_sig(const void *fit, int noffset, int required_keynode,
	char **err_msgp)
	{
	char * const exc_prop[] = {"data"};
	const char prop, end, *name;
	struct image_sign_info info;
	const uint32_t *strings;
	uint8_t *fit_value;
	int fit_value_len;
	int max_regions;
	int i, prop_len;
	char path[200];
	int count;

	debug("%s: fdt=%p, conf='%s', sig='%s'\n", __func__, gd_fdt_blob(),
	fit_get_name(fit, noffset, NULL),
	fit_get_name(gd_fdt_blob(), required_keynode, NULL));
	*err_msgp = NULL;
	if (fit_image_setup_verify(&info, fit, noffset, required_keynode,
	err_msgp))
	return -1;

	if (fit_image_hash_get_value(fit, noffset, &fit_value,
	&fit_value_len)) {
	*err_msgp = "Can't get hash value property";
	return -1;
	}

	/* Count the number of strings in the property */
	prop = fdt_getprop(fit, noffset, "hashed-nodes", &prop_len);
	end = prop ? prop + prop_len : prop;
	for (name = prop, count = 0; name < end; name++)
	if (!*name)
	count++;
	if (!count) {
	*err_msgp = "Can't get hashed-nodes property";
	return -1;
	}

	/* Add a sanity check here since we are using the stack */
	if (count > IMAGE_MAX_HASHED_NODES) {
	*err_msgp = "Number of hashed nodes exceeds maximum";
	return -1;
	}

	/* Create a list of node names from those strings */
	char *node_inc[count];

	debug("Hash nodes (%d):\n", count);
	for (name = prop, i = 0; name < end; name += strlen(name) + 1, i++) {
	debug(" '%s'\n", name);
	node_inc[i] = (char *)name;
	}

	/*
	* Each node can generate one region for each sub-node. Allow for
	* 7 sub-nodes (hash@1, signature@1, etc.) and some extra.
	*/
	max_regions = 20 + count * 7;
	struct fdt_region fdt_regions[max_regions];

	/* Get a list of regions to hash */
	count = fdt_find_regions(fit, node_inc, count,
	exc_prop, ARRAY_SIZE(exc_prop),
	fdt_regions, max_regions - 1,
	path, sizeof(path), 0);
	if (count < 0) {
	*err_msgp = "Failed to hash configuration";
	return -1;
	}
	if (count == 0) {
	*err_msgp = "No data to hash";
	return -1;
	}
	if (count >= max_regions - 1) {
	*err_msgp = "Too many hash regions";
	return -1;
	}

	/* Add the strings */
	strings = fdt_getprop(fit, noffset, "hashed-strings", NULL);
	if (strings) {
	fdt_regions[count].offset = fdt_off_dt_strings(fit) +
	fdt32_to_cpu(strings[0]);
	fdt_regions[count].size = fdt32_to_cpu(strings[1]);
	count++;
	}

	/* Allocate the region list on the stack */
	struct image_region region[count];

	fit_region_make_list(fit, fdt_regions, count, region);
	if (info.algo->verify(&info, region, count, fit_value,
	fit_value_len)) {
	*err_msgp = "Verification failed";
	return -1;
	}

	return 0;
	}

	static int fit_config_verify_sig(const void *fit, int conf_noffset,
	const void *sig_blob, int sig_offset)
	{
	int noffset;
	char *err_msg = "";
	int verified = 0;
	int ret;

	/* Process all hash subnodes of the component conf node */
	for (noffset = fdt_first_subnode(fit, conf_noffset);
	noffset >= 0;
	noffset = fdt_next_subnode(fit, noffset)) {
	const char *name = fit_get_name(fit, noffset, NULL);

	if (!strncmp(name, FIT_SIG_NODENAME,
	strlen(FIT_SIG_NODENAME))) {
	ret = fit_config_check_sig(fit, noffset, sig_offset,
	&err_msg);
	if (ret) {
	puts("- ");
	} else {
	puts("+ ");
	verified = 1;
	break;
	}
	}
	}

	if (noffset == -FDT_ERR_TRUNCATED \|\| noffset == -FDT_ERR_BADSTRUCTURE) {
	err_msg = "Corrupted or truncated tree";
	goto error;
	}

	return verified ? 0 : -EPERM;

	error:
	printf(" error!\n%s for '%s' hash node in '%s' config node\n",
	err_msg, fit_get_name(fit, noffset, NULL),
	fit_get_name(fit, conf_noffset, NULL));
	return -1;
	}

	int fit_config_verify_required_sigs(const void *fit, int conf_noffset,
	const void *sig_blob)
	{
	int noffset;
	int sig_node;

	/* Work out what we need to verify */
	sig_node = fdt_subnode_offset(sig_blob, 0, FIT_SIG_NODENAME);
	if (sig_node < 0) {
	debug("%s: No signature node found: %s\n", __func__,
	fdt_strerror(sig_node));
	return 0;
	}

	for (noffset = fdt_first_subnode(sig_blob, sig_node);
	noffset >= 0;
	noffset = fdt_next_subnode(sig_blob, noffset)) {
	const char *required;
	int ret;

	required = fdt_getprop(sig_blob, noffset, "required", NULL);
	if (!required \|\| strcmp(required, "conf"))
	continue;
	ret = fit_config_verify_sig(fit, conf_noffset, sig_blob,
	noffset);
	if (ret) {
	printf("Failed to verify required signature '%s'\n",
	fit_get_name(sig_blob, noffset, NULL));
	return ret;
	}
	}

	return 0;
	}

	int fit_config_verify(const void *fit, int conf_noffset)
	{
	return !fit_config_verify_required_sigs(fit, conf_noffset,
	gd_fdt_blob());
	}