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// SPDX-License-Identifier: GPL-2.0+
/*
* Copyright (C) 2022 Google LLC
*/
#include <asm/global_data.h>
#include <asm/io.h>
#include <android_bootloader.h>
#include <android_image.h>
#include <avb_verify.h>
#include <bcc.h>
#include <command.h>
#include <config.h>
#include <dm/uclass.h>
#include <fdt_support.h>
#include <malloc.h>
#include <rng.h>
#include <string.h>
#include <linux/err.h>
#include "avb_preloaded.h"
#include "generate_fdt.h"
/* Taken from libavb/avb_slot_verify.c */
#define VBMETA_MAX_SIZE SZ_64K
/* Taken from crosvm */
#define FDT_MAX_SIZE SZ_2M
DECLARE_GLOBAL_DATA_PTR;
static bool is_valid_ram(const void *ptr)
{
uintptr_t addr = (uintptr_t)ptr;
return CONFIG_SYS_SDRAM_BASE <= addr && addr < gd->ram_top;
}
static bool is_valid_ram_region(const void *ptr, size_t size)
{
return is_valid_ram(ptr) && (size <= gd->ram_top - (uintptr_t)ptr);
}
static struct AvbOps *alloc_avb_ops(void *image, size_t size)
{
int error;
AvbFooter footer;
const void *avb_footer = image + size - AVB_FOOTER_SIZE;
struct AvbOps *ops = avb_preloaded_alloc();
if (!ops)
return NULL;
if (size < AVB_FOOTER_SIZE ||
!avb_footer_validate_and_byteswap(avb_footer, &footer) ||
!is_valid_ram_region(image, footer.original_image_size) ||
!is_valid_ram_region(image + footer.vbmeta_offset, VBMETA_MAX_SIZE))
goto free_ops;
error = avb_preloaded_add_part(ops, "boot", image,
footer.original_image_size);
if (error)
goto free_ops;
/*
* We can't simply use footer.vbmeta_size as avb_slot_verify() requires
* the partition to be VBMETA_MAX_SIZE; as the image was created through
* avbtool, there should always be enough 0-padding after the actual
* vbmeta data to safely meet that requirement.
*/
error = avb_preloaded_add_part(ops, "vbmeta",
image + footer.vbmeta_offset,
VBMETA_MAX_SIZE);
if (error)
goto free_ops;
return ops;
free_ops:
avb_preloaded_free(ops);
return NULL;
}
static int verify_image(void *image, size_t size, struct boot_config *cfg)
{
const char *instance_uuid = "90d2174a-038a-4bc6-adf3-824848fc5825";
const char *iface_str = "virtio";
const int devnum = 1;
int ret = 0;
const char *parts[] = { "boot", NULL };
AvbSlotVerifyData *data = NULL;
struct AvbOps *ops = NULL;
ops = alloc_avb_ops(image, size);
if (!ops)
return -ENOMEM;
ret = avb_slot_verify(ops, parts, /*slot_suffix=*/"",
AVB_SLOT_VERIFY_FLAGS_NONE,
AVB_HASHTREE_ERROR_MODE_RESTART_AND_INVALIDATE,
&data);
if (ret != AVB_SLOT_VERIFY_RESULT_OK) {
ret = -EACCES;
goto err;
}
cfg->new_instance = false;
ret = bcc_vm_instance_handover(iface_str, devnum, instance_uuid,
/*must_exist=*/false, "vm_entry",
BCC_MODE_NORMAL, data, NULL,
cfg, sizeof(*cfg));
if (ret < 0)
goto err;
cfg->new_instance = (ret == BCC_VM_INSTANCE_CREATED);
ret = 0;
err:
if (data)
avb_slot_verify_data_free(data);
if (ops)
avb_preloaded_free(ops);
return ret;
}
static int seed_u64(uint64_t *seed)
{
int res;
struct udevice *dev;
res = uclass_get_device_by_name(UCLASS_RNG, "smccc-trng", &dev);
if (res)
return res;
return dm_rng_read(dev, seed, sizeof(*seed));
}
int pvmfw_boot_flow(void *fdt, size_t fdt_max_size, void *image, size_t size,
void *bcc, size_t bcc_size)
{
int ret;
struct boot_config cfg = {
.bcc_addr = virt_to_phys(bcc),
.bcc_size = bcc_size,
};
if (!size || !is_valid_ram_region(image, size)) {
ret = -EPERM;
goto err;
}
if (fdt != (const void *)CONFIG_SYS_SDRAM_BASE) {
ret = -EFAULT;
goto err;
}
if (fdt_totalsize(fdt) > fdt_max_size) {
ret = -E2BIG;
goto err;
}
bcc_set_handover(bcc, bcc_size);
ret = parse_input_fdt(fdt, &cfg);
if (ret)
goto err;
ret = verify_image(image, size, &cfg);
if (ret)
goto err;
ret = transfer_fdt_template(fdt, fdt_max_size);
if (ret)
goto err;
ret = seed_u64(&cfg.kaslr_seed);
if (ret)
goto err;
ret = patch_output_fdt(fdt, &cfg);
err:
if (ret)
bcc_clear_memory(bcc, bcc_size);
return ret;
}
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