1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * Unified UUID/GUID definition
  4 *
  5 * Copyright (C) 2009, 2016 Intel Corp.
  6 *	Huang Ying <ying.huang@intel.com>
  7 */
  8
  9#include <linux/kernel.h>
 10#include <linux/ctype.h>
 11#include <linux/errno.h>
 12#include <linux/export.h>
 13#include <linux/uuid.h>
 14#include <linux/random.h>
 15
 16const guid_t guid_null;
 17EXPORT_SYMBOL(guid_null);
 18const uuid_t uuid_null;
 19EXPORT_SYMBOL(uuid_null);
 20
 21const u8 guid_index[16] = {3,2,1,0,5,4,7,6,8,9,10,11,12,13,14,15};
 22const u8 uuid_index[16] = {0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15};
 23
 24/**
 25 * generate_random_uuid - generate a random UUID
 26 * @uuid: where to put the generated UUID
 27 *
 28 * Random UUID interface
 29 *
 30 * Used to create a Boot ID or a filesystem UUID/GUID, but can be
 31 * useful for other kernel drivers.
 32 */
 33void generate_random_uuid(unsigned char uuid[16])
 34{
 35	get_random_bytes(uuid, 16);
 36	/* Set UUID version to 4 --- truly random generation */
 37	uuid[6] = (uuid[6] & 0x0F) | 0x40;
 38	/* Set the UUID variant to DCE */
 39	uuid[8] = (uuid[8] & 0x3F) | 0x80;
 40}
 41EXPORT_SYMBOL(generate_random_uuid);
 42
 43void generate_random_guid(unsigned char guid[16])
 44{
 45	get_random_bytes(guid, 16);
 46	/* Set GUID version to 4 --- truly random generation */
 47	guid[7] = (guid[7] & 0x0F) | 0x40;
 48	/* Set the GUID variant to DCE */
 49	guid[8] = (guid[8] & 0x3F) | 0x80;
 50}
 51EXPORT_SYMBOL(generate_random_guid);
 52
 53static void __uuid_gen_common(__u8 b[16])
 54{
 55	prandom_bytes(b, 16);
 56	/* reversion 0b10 */
 57	b[8] = (b[8] & 0x3F) | 0x80;
 58}
 59
 60void guid_gen(guid_t *lu)
 61{
 62	__uuid_gen_common(lu->b);
 63	/* version 4 : random generation */
 64	lu->b[7] = (lu->b[7] & 0x0F) | 0x40;
 65}
 66EXPORT_SYMBOL_GPL(guid_gen);
 67
 68void uuid_gen(uuid_t *bu)
 69{
 70	__uuid_gen_common(bu->b);
 71	/* version 4 : random generation */
 72	bu->b[6] = (bu->b[6] & 0x0F) | 0x40;
 73}
 74EXPORT_SYMBOL_GPL(uuid_gen);
 75
 76/**
 77 * uuid_is_valid - checks if a UUID string is valid
 78 * @uuid:	UUID string to check
 79 *
 80 * Description:
 81 * It checks if the UUID string is following the format:
 82 *	xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx
 83 *
 84 * where x is a hex digit.
 85 *
 86 * Return: true if input is valid UUID string.
 87 */
 88bool uuid_is_valid(const char *uuid)
 89{
 90	unsigned int i;
 91
 92	for (i = 0; i < UUID_STRING_LEN; i++) {
 93		if (i == 8 || i == 13 || i == 18 || i == 23) {
 94			if (uuid[i] != '-')
 95				return false;
 96		} else if (!isxdigit(uuid[i])) {
 97			return false;
 98		}
 99	}
100
101	return true;
102}
103EXPORT_SYMBOL(uuid_is_valid);
104
105static int __uuid_parse(const char *uuid, __u8 b[16], const u8 ei[16])
106{
107	static const u8 si[16] = {0,2,4,6,9,11,14,16,19,21,24,26,28,30,32,34};
108	unsigned int i;
109
110	if (!uuid_is_valid(uuid))
111		return -EINVAL;
112
113	for (i = 0; i < 16; i++) {
114		int hi = hex_to_bin(uuid[si[i] + 0]);
115		int lo = hex_to_bin(uuid[si[i] + 1]);
116
117		b[ei[i]] = (hi << 4) | lo;
118	}
119
120	return 0;
121}
122
123int guid_parse(const char *uuid, guid_t *u)
124{
125	return __uuid_parse(uuid, u->b, guid_index);
126}
127EXPORT_SYMBOL(guid_parse);
128
129int uuid_parse(const char *uuid, uuid_t *u)
130{
131	return __uuid_parse(uuid, u->b, uuid_index);
132}
133EXPORT_SYMBOL(uuid_parse);