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
16 const guid_t guid_null;
17 EXPORT_SYMBOL(guid_null);
18 const uuid_t uuid_null;
19 EXPORT_SYMBOL(uuid_null);
20
21 const u8 guid_index[16] = {3,2,1,0,5,4,7,6,8,9,10,11,12,13,14,15};
22 const 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 */
33 void 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 }
41 EXPORT_SYMBOL(generate_random_uuid);
42
43 void 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 }
51 EXPORT_SYMBOL(generate_random_guid);
52
53 static 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
60 void 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 }
66 EXPORT_SYMBOL_GPL(guid_gen);
67
68 void 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 }
74 EXPORT_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 */
88 bool 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 }
103 EXPORT_SYMBOL(uuid_is_valid);
104
105 static 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
123 int guid_parse(const char *uuid, guid_t *u)
124 {
125 return __uuid_parse(uuid, u->b, guid_index);
126 }
127 EXPORT_SYMBOL(guid_parse);
128
129 int uuid_parse(const char *uuid, uuid_t *u)
130 {
131 return __uuid_parse(uuid, u->b, uuid_index);
132 }
133 EXPORT_SYMBOL(uuid_parse);
134
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