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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 <[email protected]>
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/hex.h>
14#include <linux/uuid.h>
15#include <linux/random.h>
16
17const guid_t guid_null;
18EXPORT_SYMBOL(guid_null);
19const uuid_t uuid_null;
20EXPORT_SYMBOL(uuid_null);
21
22const u8 guid_index[16] = {3,2,1,0,5,4,7,6,8,9,10,11,12,13,14,15};
23const u8 uuid_index[16] = {0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15};
24
25/**
26 * generate_random_uuid - generate a random UUID
27 * @uuid: where to put the generated UUID
28 *
29 * Random UUID interface
30 *
31 * Used to create a Boot ID or a filesystem UUID/GUID, but can be
32 * useful for other kernel drivers.
33 */
34void generate_random_uuid(unsigned char uuid[16])
35{
36 get_random_bytes(uuid, 16);
37 /* Set UUID version to 4 --- truly random generation */
38 uuid[6] = (uuid[6] & 0x0F) | 0x40;
39 /* Set the UUID variant to DCE */
40 uuid[8] = (uuid[8] & 0x3F) | 0x80;
41}
42EXPORT_SYMBOL(generate_random_uuid);
43
44void generate_random_guid(unsigned char guid[16])
45{
46 get_random_bytes(guid, 16);
47 /* Set GUID version to 4 --- truly random generation */
48 guid[7] = (guid[7] & 0x0F) | 0x40;
49 /* Set the GUID variant to DCE */
50 guid[8] = (guid[8] & 0x3F) | 0x80;
51}
52EXPORT_SYMBOL(generate_random_guid);
53
54static void __uuid_gen_common(__u8 b[16])
55{
56 get_random_bytes(b, 16);
57 /* revision 0b10 */
58 b[8] = (b[8] & 0x3F) | 0x80;
59}
60
61void guid_gen(guid_t *lu)
62{
63 __uuid_gen_common(lu->b);
64 /* version 4 : random generation */
65 lu->b[7] = (lu->b[7] & 0x0F) | 0x40;
66}
67EXPORT_SYMBOL_GPL(guid_gen);
68
69void uuid_gen(uuid_t *bu)
70{
71 __uuid_gen_common(bu->b);
72 /* version 4 : random generation */
73 bu->b[6] = (bu->b[6] & 0x0F) | 0x40;
74}
75EXPORT_SYMBOL_GPL(uuid_gen);
76
77/**
78 * uuid_is_valid - checks if a UUID string is valid
79 * @uuid: UUID string to check
80 *
81 * Description:
82 * It checks if the UUID string is following the format:
83 * xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx
84 *
85 * where x is a hex digit.
86 *
87 * Return: true if input is valid UUID string.
88 */
89bool uuid_is_valid(const char *uuid)
90{
91 unsigned int i;
92
93 for (i = 0; i < UUID_STRING_LEN; i++) {
94 if (i == 8 || i == 13 || i == 18 || i == 23) {
95 if (uuid[i] != '-')
96 return false;
97 } else if (!isxdigit(uuid[i])) {
98 return false;
99 }
100 }
101
102 return true;
103}
104EXPORT_SYMBOL(uuid_is_valid);
105
106static int __uuid_parse(const char *uuid, __u8 b[16], const u8 ei[16])
107{
108 static const u8 si[16] = {0,2,4,6,9,11,14,16,19,21,24,26,28,30,32,34};
109 unsigned int i;
110
111 if (!uuid_is_valid(uuid))
112 return -EINVAL;
113
114 for (i = 0; i < 16; i++) {
115 int hi = hex_to_bin(uuid[si[i] + 0]);
116 int lo = hex_to_bin(uuid[si[i] + 1]);
117
118 b[ei[i]] = (hi << 4) | lo;
119 }
120
121 return 0;
122}
123
124int guid_parse(const char *uuid, guid_t *u)
125{
126 return __uuid_parse(uuid, u->b, guid_index);
127}
128EXPORT_SYMBOL(guid_parse);
129
130int uuid_parse(const char *uuid, uuid_t *u)
131{
132 return __uuid_parse(uuid, u->b, uuid_index);
133}
134EXPORT_SYMBOL(uuid_parse);