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     ˆÁÇƒuÆÀÂÅ ß    // SPDX-License-Identifier: (GPL-2.0-or-later OR BSD-2-Clause)
/*
 * libfdt - Flat Device Tree manipulation
 * Copyright (C) 2006 David Gibson, IBM Corporation.
 */
#include "libfdt_env.h"

#include <fdt.h>
#include <libfdt.h>

#include "libfdt_internal.h"

/*
 * Minimal sanity check for a read-only tree. fdt_ro_probe_() checks
 * that the given buffer contains what appears to be a flattened
 * device tree with sane information in its header.
 */
int32_t fdt_ro_probe_(const void *fdt)
{
	uint32_t totalsize = fdt_totalsize(fdt);

	if (can_assume(VALID_DTB))
		return totalsize;

	/* The device tree must be at an 8-byte aligned address */
	if ((uintptr_t)fdt & 7)
		return -FDT_ERR_ALIGNMENT;

	if (fdt_magic(fdt) == FDT_MAGIC) {
		/* Complete tree */
		if (!can_assume(LATEST)) {
			if (fdt_version(fdt) < FDT_FIRST_SUPPORTED_VERSION)
				return -FDT_ERR_BADVERSION;
			if (fdt_last_comp_version(fdt) >
					FDT_LAST_SUPPORTED_VERSION)
				return -FDT_ERR_BADVERSION;
		}
	} else if (fdt_magic(fdt) == FDT_SW_MAGIC) {
		/* Unfinished sequential-write blob */
		if (!can_assume(VALID_INPUT) && fdt_size_dt_struct(fdt) == 0)
			return -FDT_ERR_BADSTATE;
	} else {
		return -FDT_ERR_BADMAGIC;
	}

	if (totalsize < INT32_MAX)
		return totalsize;
	else
		return -FDT_ERR_TRUNCATED;
}

static int check_off_(uint32_t hdrsize, uint32_t totalsize, uint32_t off)
{
	return (off >= hdrsize) && (off <= totalsize);
}

static int check_block_(uint32_t hdrsize, uint32_t totalsize,
			uint32_t base, uint32_t size)
{
	if (!check_off_(hdrsize, totalsize, base))
		return 0; /* block start out of bounds */
	if ((base + size) < base)
		return 0; /* overflow */
	if (!check_off_(hdrsize, totalsize, base + size))
		return 0; /* block end out of bounds */
	return 1;
}

size_t fdt_header_size_(uint32_t version)
{
	if (version <= 1)
		return FDT_V1_SIZE;
	else if (version <= 2)
		return FDT_V2_SIZE;
	else if (version <= 3)
		return FDT_V3_SIZE;
	else if (version <= 16)
		return FDT_V16_SIZE;
	else
		return FDT_V17_SIZE;
}

size_t fdt_header_size(const void *fdt)
{
	return can_assume(LATEST) ? FDT_V17_SIZE :
		fdt_header_size_(fdt_version(fdt));
}

int fdt_check_header(const void *fdt)
{
	size_t hdrsize;

	if (fdt_magic(fdt) != FDT_MAGIC)
		return -FDT_ERR_BADMAGIC;
	if (!can_assume(LATEST)) {
		if ((fdt_version(fdt) < FDT_FIRST_SUPPORTED_VERSION)
		    || (fdt_last_comp_version(fdt) >
			FDT_LAST_SUPPORTED_VERSION))
			return -FDT_ERR_BADVERSION;
		if (fdt_version(fdt) < fdt_last_comp_version(fdt))
			return -FDT_ERR_BADVERSION;
	}
	hdrsize = fdt_header_size(fdt);
	if (!can_assume(VALID_DTB)) {

		if ((fdt_totalsize(fdt) < hdrsize)
		    || (fdt_totalsize(fdt) > INT_MAX))
			return -FDT_ERR_TRUNCATED;

		/* Bounds check memrsv block */
		if (!check_off_(hdrsize, fdt_totalsize(fdt),
				fdt_off_mem_rsvmap(fdt)))
			return -FDT_ERR_TRUNCATED;
	}

	if (!can_assume(VALID_DTB)) {
		/* Bounds check structure block */
		if (!can_assume(LATEST) && fdt_version(fdt) < 17) {
			if (!check_off_(hdrsize, fdt_totalsize(fdt),
					fdt_off_dt_struct(fdt)))
				return -FDT_ERR_TRUNCATED;
		} else {
			if (!check_block_(hdrsize, fdt_totalsize(fdt),
					  fdt_off_dt_struct(fdt),
					  fdt_size_dt_struct(fdt)))
				return -FDT_ERR_TRUNCATED;
		}

		/* Bounds check strings block */
		if (!check_block_(hdrsize, fdt_totalsize(fdt),
				  fdt_off_dt_strings(fdt),
				  fdt_size_dt_strings(fdt)))
			return -FDT_ERR_TRUNCATED;
	}

	return 0;
}

const void *fdt_offset_ptr(const void *fdt, int offset, unsigned int len)
{
	unsigned int uoffset = offset;
	unsigned int absoffset = offset + fdt_off_dt_struct(fdt);

	if (offset < 0)
		return NULL;

	if (!can_assume(VALID_INPUT))
		if ((absoffset < uoffset)
		    || ((absoffset + len) < absoffset)
		    || (absoffset + len) > fdt_totalsize(fdt))
			return NULL;

	if (can_assume(LATEST) || fdt_version(fdt) >= 0x11)
		if (((uoffset + len) < uoffset)
		    || ((offset + len) > fdt_size_dt_struct(fdt)))
			return NULL;

	return fdt_offset_ptr_(fdt, offset);
}

uint32_t fdt_next_tag(const void *fdt, int startoffs