acrn-hypervisor/hypervisor/boot/sbl/abl_seed_parse.c

/*
 * Copyright (C) 2018 Intel Corporation. All rights reserved.
 *
 * SPDX-License-Identifier: BSD-3-Clause
 */

#include <hypervisor.h>
#include <abl_seed_parse.h>

#define ABL_SEED_LEN 32U
struct abl_seed_info {
	uint8_t svn;
	uint8_t reserved[3];
	uint8_t seed[ABL_SEED_LEN];
};

#define ABL_SEED_LIST_MAX 4U
struct dev_sec_info {
	uint32_t size_of_this_struct;
	uint32_t version;
	uint32_t num_seeds;
	struct abl_seed_info seed_list[ABL_SEED_LIST_MAX];
};

static const char *dev_sec_info_arg= "dev_sec_info.param_addr=";

static void parse_seed_list_abl(void *param_addr)
{
	uint32_t i;
	uint32_t legacy_seed_index = 0U;
	struct seed_info dseed_list[BOOTLOADER_SEED_MAX_ENTRIES];
	struct dev_sec_info *sec_info = (struct dev_sec_info *)param_addr;

	if (sec_info == NULL) {
		goto fail;
	}

	if (sec_info->num_seeds < 2U ||
			sec_info->num_seeds > ABL_SEED_LIST_MAX) {
		goto fail;
	}

	/*
	 * The seed_list from ABL contains several seeds which based on SVN
	 * and one legacy seed which is not based on SVN. The legacy seed's
	 * svn value is minimum in the seed list. And CSE ensures at least two
	 * seeds will be generated which will contain the legacy seed.
	 * Here find the legacy seed index first.
	 */
	for (i = 1U; i < sec_info->num_seeds; i++) {
		if (sec_info->seed_list[i].svn <
				sec_info->seed_list[legacy_seed_index].svn) {
			legacy_seed_index = i;
		}
	}

	/*
	 * Copy out abl_seed for trusty and clear the original seed in memory.
	 * The SOS requires the legacy seed to derive RPMB key. So skip the
	 * legacy seed when clear original seed.
	 */
	(void)memset((void *)dseed_list, 0U, sizeof(dseed_list));
	for (i = 0U; i < sec_info->num_seeds; i++) {
		dseed_list[i].cse_svn = sec_info->seed_list[i].svn;
		(void)memcpy_s((void *)dseed_list[i].seed,
				sizeof(dseed_list[i].seed),
				(void *)sec_info->seed_list[i].seed,
				sizeof(sec_info->seed_list[i].seed));

		if (i == legacy_seed_index) {
			continue;
		}

		(void)memset((void *)sec_info->seed_list[i].seed, 0U,
				sizeof(sec_info->seed_list[i].seed));
	}

	trusty_set_dseed((void *)dseed_list, (uint8_t)(sec_info->num_seeds));
	(void)memset((void *)dseed_list, 0U, sizeof(dseed_list));
	return;
fail:
	trusty_set_dseed(NULL, 0U);
	(void)memset((void *)dseed_list, 0U, sizeof(dseed_list));
}

/*
 * abl_seed_parse
 *
 * description:
 *    This function parse dev_sec_info from cmdline. Mainly on
 *    1. parse structure address from cmdline
 *    2. call  parse_seed_list_abl to parse seed_list
 *    3. convert address in the structure from HPA to SOS's GPA
 *    4. clear original image_boot_params argument in cmdline since
 *       original address is HPA.
 *
 * input:
 *    vm            pointer to vm structure
 *    cmdline       pointer to cmdline string
 *    out_len       the max len of out_arg
 *
 * output:
 *    out_arg       the argument with SOS's GPA
 *
 * return value:
 *    true if parse successfully, otherwise false.
 */
bool abl_seed_parse(struct acrn_vm *vm, char *cmdline, char *out_arg, uint32_t out_len)
{
	char *arg, *arg_end;
	char *param;
	void *param_addr;
	uint32_t len;

	if (cmdline == NULL) {
		goto fail;
	}

	len = strnlen_s(dev_sec_info_arg, MEM_1K);
	arg = strstr_s(cmdline, MEM_2K, dev_sec_info_arg, len);

	if (arg == NULL) {
		goto fail;
	}

	param = arg + len;
	param_addr = (void *)hpa2hva(strtoul_hex(param));
	if (param_addr == NULL) {
		goto fail;
	}

	parse_seed_list_abl(param_addr);

	/*
	 * Replace original arguments with spaces since SOS's GPA is not
	 * identity mapped to HPA. The argument will be appended later when
	 * compose cmdline for SOS.
	 */
	arg_end = strchr(arg, ' ');
	len = (arg_end != NULL) ? (uint32_t)(arg_end - arg) :
							strnlen_s(arg, MEM_2K);
	(void)memset((void *)arg, ' ', len);

	/* Convert the param_addr to SOS GPA and copy to caller */
	if (out_arg != NULL) {
		snprintf(out_arg, out_len, "%s0x%X ",
			dev_sec_info_arg, hva2gpa(vm, param_addr));
	}

	return true;

fail:
	parse_seed_list_abl(NULL);
	return false;
}