xref: /arm-trusted-firmware/plat/arm/board/juno/juno_trusted_boot.c (revision 91f16700b400a8c0651d24a598fc48ee2997a0d7)

/*
 * Copyright (c) 2019-2020, ARM Limited. All rights reserved.
 *
 * SPDX-License-Identifier: BSD-3-Clause
 */

#include <assert.h>
#include <stdint.h>
#include <string.h>

#include <plat/arm/common/plat_arm.h>
#include <plat/common/common_def.h>
#include <plat/common/platform.h>

#if (ARM_ROTPK_LOCATION_ID == ARM_ROTPK_REGS_ID)

static unsigned char rotpk_hash_der[ARM_ROTPK_HEADER_LEN + ARM_ROTPK_HASH_LEN];

extern unsigned char arm_rotpk_header[];

/*
 * Return the ROTPK hash stored in the registers of Juno board.
 */
static int juno_get_rotpk_info_regs(void **key_ptr, unsigned int *key_len,
			unsigned int *flags)
{
	uint8_t *dst;
	uint32_t *src, tmp;
	unsigned int words, i;

	assert(key_ptr != NULL);
	assert(key_len != NULL);
	assert(flags != NULL);

	/* Copy the DER header */
	memcpy(rotpk_hash_der, arm_rotpk_header, ARM_ROTPK_HEADER_LEN);
	dst = (uint8_t *)&rotpk_hash_der[ARM_ROTPK_HEADER_LEN];


	/*
	 * Append the hash from Trusted Root-Key Storage registers. The hash has
	 * not been written linearly into the registers, so we have to do a bit
	 * of byte swapping:
	 *
	 *     0x00    0x04    0x08    0x0C    0x10    0x14    0x18    0x1C
	 * +---------------------------------------------------------------+
	 * | Reg0  | Reg1  | Reg2  | Reg3  | Reg4  | Reg5  | Reg6  | Reg7  |
	 * +---------------------------------------------------------------+
	 *  | ...                    ... |   | ...                   ...  |
	 *  |       +--------------------+   |                    +-------+
	 *  |       |                        |                    |
	 *  +----------------------------+   +----------------------------+
	 *          |                    |                        |       |
	 *  +-------+                    |   +--------------------+       |
	 *  |                            |   |                            |
	 *  v                            v   v                            v
	 * +---------------------------------------------------------------+
	 * |                               |                               |
	 * +---------------------------------------------------------------+
	 *  0                           15  16                           31
	 *
	 * Additionally, we have to access the registers in 32-bit words
	 */
	words = ARM_ROTPK_HASH_LEN >> 3;

	/* Swap bytes 0-15 (first four registers) */
	src = (uint32_t *)TZ_PUB_KEY_HASH_BASE;
	for (i = 0 ; i < words ; i++) {
		tmp = src[words - 1 - i];
		/* Words are read in little endian */
		*dst++ = (uint8_t)((tmp >> 24) & 0xFF);
		*dst++ = (uint8_t)((tmp >> 16) & 0xFF);
		*dst++ = (uint8_t)((tmp >> 8) & 0xFF);
		*dst++ = (uint8_t)(tmp & 0xFF);
	}

	/* Swap bytes 16-31 (last four registers) */
	src = (uint32_t *)(TZ_PUB_KEY_HASH_BASE + ARM_ROTPK_HASH_LEN / 2);
	for (i = 0 ; i < words ; i++) {
		tmp = src[words - 1 - i];
		*dst++ = (uint8_t)((tmp >> 24) & 0xFF);
		*dst++ = (uint8_t)((tmp >> 16) & 0xFF);
		*dst++ = (uint8_t)((tmp >> 8) & 0xFF);
		*dst++ = (uint8_t)(tmp & 0xFF);
	}

	*key_ptr = (void *)rotpk_hash_der;
	*key_len = (unsigned int)sizeof(rotpk_hash_der);
	*flags = ROTPK_IS_HASH;
	return 0;
}

#endif

/*
 * Return the ROTPK hash in the following ASN.1 structure in DER format:
 *
 * AlgorithmIdentifier  ::=  SEQUENCE  {
 *     algorithm         OBJECT IDENTIFIER,
 *     parameters        ANY DEFINED BY algorithm OPTIONAL
 * }
 *
 * DigestInfo ::= SEQUENCE {
 *     digestAlgorithm   AlgorithmIdentifier,
 *     digest            OCTET STRING
 * }
 */
int plat_get_rotpk_info(void *cookie, void **key_ptr, unsigned int *key_len,
			unsigned int *flags)
{
#if (ARM_ROTPK_LOCATION_ID == ARM_ROTPK_DEVEL_RSA_ID) || \
    (ARM_ROTPK_LOCATION_ID == ARM_ROTPK_DEVEL_ECDSA_ID)
	return arm_get_rotpk_info_dev(key_ptr, key_len, flags);
#elif (ARM_ROTPK_LOCATION_ID == ARM_ROTPK_REGS_ID)
	return juno_get_rotpk_info_regs(key_ptr, key_len, flags);
#else
	return 1;
#endif
}