board/amlogic/g12b_newman_bx/permanent_attributes.c

/*
 * Copyright (c) 2019 The Fuchsia Authors
 *
 * SPDX-License-Identifier:	BSD-3-Clause
 */

#include <common.h>
#include <libavb/libavb.h>
#include <libavb_atx/libavb_atx.h>
#include <tee/ta_vx_helper.h>
#include <u-boot/sha256.h>

#ifdef DEV_BUILD_CONFIG
#include "avb_dev_attrs/atx_permanent_attrs.h"
#elif defined(DOGFOOD_BUILD_CONFIG)
#include "avb_dogfood_attrs/atx_permanent_attrs.h"
#elif defined(PROD_BUILD_CONFIG)
#include "avb_prod_attrs/atx_permanent_attrs.h"
#else
#error "Unknown build config"
#endif

_Static_assert(sizeof(avb_atx_permanent_attributes_hash) ==
		       AVB_SHA256_DIGEST_SIZE,
	       "AVB digest size mismatch");

AvbIOResult avb_read_permanent_attributes(AvbAtxOps *atx_ops,
					  AvbAtxPermanentAttributes *attributes)
{
	size_t bytes_read = 0;
	int ret = ta_vx_read_perm_attr(attributes, sizeof(*attributes),
				       &bytes_read);
	if (ret != 0) {
		printf("Failed to read perm attrs from VX TA (error 0x%X)\n",
		       ret);
		return AVB_IO_RESULT_ERROR_IO;
	}
	if (bytes_read != sizeof(*attributes)) {
		printf("VX TA perm attr size error (expected %zu, got %zu)\n",
		       sizeof(*attributes), bytes_read);
		return AVB_IO_RESULT_ERROR_INVALID_VALUE_SIZE;
	}
	return AVB_IO_RESULT_OK;
}

AvbIOResult
avb_read_permanent_attributes_hash(AvbAtxOps *atx_ops,
				   uint8_t hash[AVB_SHA256_DIGEST_SIZE])
{
	/* Even though the VX TA could provide the permanent attribute hash as
	 * well, keeping it here has two purposes:
	 *  1. Ensures matching VX/u-boot builds; libavb will refuse to validate
	 *     if the hash doesn't match the attributes.
	 *  2. We use the presence of the hash bytestring in a u-boot image to
	 *     determine what variant that image is, which is necessary to
	 *     validate that we're signing the right one. */
	memcpy(hash, avb_atx_permanent_attributes_hash, AVB_SHA256_DIGEST_SIZE);
	return AVB_IO_RESULT_OK;
}