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	get_random_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);
134