path: root/drivers/thunderbolt/property.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Thunderbolt XDomain property support
 *
 * Copyright (C) 2017, Intel Corporation
 * Authors: Michael Jamet <michael.jamet@intel.com>
 *          Mika Westerberg <mika.westerberg@linux.intel.com>
 */

#include <linux/err.h>
#include <linux/overflow.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/uuid.h>
#include <linux/thunderbolt.h>

struct tb_property_entry {
	u32 key_hi;
	u32 key_lo;
	u16 length;
	u8 reserved;
	u8 type;
	u32 value;
};

struct tb_property_rootdir_entry {
	u32 magic;
	u32 length;
	struct tb_property_entry entries[];
};

struct tb_property_dir_entry {
	u32 uuid[4];
	struct tb_property_entry entries[];
};

#define TB_PROPERTY_ROOTDIR_MAGIC	0x55584401
#define TB_PROPERTY_MAX_DEPTH		8

static struct tb_property_dir *__tb_property_parse_dir(const u32 *block,
	size_t block_len, unsigned int dir_offset, size_t dir_len,
	bool is_root, unsigned int depth);
static struct tb_property *tb_property_copy(const struct tb_property *property);

static inline void parse_dwdata(void *dst, const void *src, size_t dwords)
{
	be32_to_cpu_array(dst, src, dwords);
}

static inline void format_dwdata(void *dst, const void *src, size_t dwords)
{
	cpu_to_be32_array(dst, src, dwords);
}

static bool tb_property_entry_valid(const struct tb_property_entry *entry,
				  size_t block_len)
{
	u32 end;

	switch (entry->type) {
	case TB_PROPERTY_TYPE_DIRECTORY:
	case TB_PROPERTY_TYPE_DATA:
	case TB_PROPERTY_TYPE_TEXT:
		if (!entry->length)
			return false;
		if (entry->length > block_len)
			return false;
		if (check_add_overflow(entry->value, entry->length, &end) ||
		    end > block_len)
			return false;
		break;

	case TB_PROPERTY_TYPE_VALUE:
		if (entry->length != 1)
			return false;
		break;
	}

	return true;
}

static bool tb_property_key_valid(const char *key)
{
	return key && strlen(key) <= TB_PROPERTY_KEY_SIZE;
}

static struct tb_property *
tb_property_alloc(const char *key, enum tb_property_type type)
{
	struct tb_property *property;

	property = kzalloc_obj(*property);
	if (!property)
		return NULL;

	strcpy(property->key, key);
	property->type = type;
	INIT_LIST_HEAD(&property->list);

	return property;
}

static struct tb_property *tb_property_parse(const u32 *block, size_t block_len,
					const struct tb_property_entry *entry,
					unsigned int depth)
{
	char key[TB_PROPERTY_KEY_SIZE + 1];
	struct tb_property *property;
	struct tb_property_dir *dir;

	if (!tb_property_entry_valid(entry, block_len))
		return NULL;

	parse_dwdata(key, entry, 2);
	key[TB_PROPERTY_KEY_SIZE] = '\0';

	property = tb_property_alloc(key, entry->type);
	if (!property)
		return NULL;

	property->length = entry->length;

	switch (property->type) {
	case TB_PROPERTY_TYPE_DIRECTORY:
		dir = __tb_property_parse_dir(block, block_len, entry->value,
					      entry->length, false, depth + 1);
		if (!dir) {
			kfree(property);
			return NULL;
		}
		property->value.dir = dir;
		break;

	case TB_PROPERTY_TYPE_DATA:
		property->value.data = kcalloc(property->length, sizeof(u32),
					       GFP_KERNEL);
		if (!property->value.data) {
			kfree(property);
			return NULL;
		}
		parse_dwdata(property->value.data, block + entry->value,
			     entry->length);
		break;

	case TB_PROPERTY_TYPE_TEXT:
		property->value.text = kcalloc(property->length, sizeof(u32),
					       GFP_KERNEL);
		if (!property->value.text) {
			kfree(property);
			return NULL;
		}
		parse_dwdata(property->value.text, block + entry->value,
			     entry->length);
		/* Force null termination */
		property->value.text[property->length * 4 - 1] = '\0';
		break;

	case TB_PROPERTY_TYPE_VALUE:
		property->value.immediate = entry->value;
		break;

	default:
		property->type = TB_PROPERTY_TYPE_UNKNOWN;
		break;
	}

	return property;
}

static struct tb_property_dir *__tb_property_parse_dir(const u32 *block,
	size_t block_len, unsigned int dir_offset, size_t dir_len