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 */
generate_random_uuid(unsigned char uuid[16])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
__uuid_gen_common(__u8 b[16])43 static void __uuid_gen_common(__u8 b[16])
44 {
45 prandom_bytes(b, 16);
46 /* reversion 0b10 */
47 b[8] = (b[8] & 0x3F) | 0x80;
48 }
49
guid_gen(guid_t * lu)50 void guid_gen(guid_t *lu)
51 {
52 __uuid_gen_common(lu->b);
53 /* version 4 : random generation */
54 lu->b[7] = (lu->b[7] & 0x0F) | 0x40;
55 }
56 EXPORT_SYMBOL_GPL(guid_gen);
57
uuid_gen(uuid_t * bu)58 void uuid_gen(uuid_t *bu)
59 {
60 __uuid_gen_common(bu->b);
61 /* version 4 : random generation */
62 bu->b[6] = (bu->b[6] & 0x0F) | 0x40;
63 }
64 EXPORT_SYMBOL_GPL(uuid_gen);
65
66 /**
67 * uuid_is_valid - checks if a UUID string is valid
68 * @uuid: UUID string to check
69 *
70 * Description:
71 * It checks if the UUID string is following the format:
72 * xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx
73 *
74 * where x is a hex digit.
75 *
76 * Return: true if input is valid UUID string.
77 */
uuid_is_valid(const char * uuid)78 bool uuid_is_valid(const char *uuid)
79 {
80 unsigned int i;
81
82 for (i = 0; i < UUID_STRING_LEN; i++) {
83 if (i == 8 || i == 13 || i == 18 || i == 23) {
84 if (uuid[i] != '-')
85 return false;
86 } else if (!isxdigit(uuid[i])) {
87 return false;
88 }
89 }
90
91 return true;
92 }
93 EXPORT_SYMBOL(uuid_is_valid);
94
__uuid_parse(const char * uuid,__u8 b[16],const u8 ei[16])95 static int __uuid_parse(const char *uuid, __u8 b[16], const u8 ei[16])
96 {
97 static const u8 si[16] = {0,2,4,6,9,11,14,16,19,21,24,26,28,30,32,34};
98 unsigned int i;
99
100 if (!uuid_is_valid(uuid))
101 return -EINVAL;
102
103 for (i = 0; i < 16; i++) {
104 int hi = hex_to_bin(uuid[si[i] + 0]);
105 int lo = hex_to_bin(uuid[si[i] + 1]);
106
107 b[ei[i]] = (hi << 4) | lo;
108 }
109
110 return 0;
111 }
112
guid_parse(const char * uuid,guid_t * u)113 int guid_parse(const char *uuid, guid_t *u)
114 {
115 return __uuid_parse(uuid, u->b, guid_index);
116 }
117 EXPORT_SYMBOL(guid_parse);
118
uuid_parse(const char * uuid,uuid_t * u)119 int uuid_parse(const char *uuid, uuid_t *u)
120 {
121 return __uuid_parse(uuid, u->b, uuid_index);
122 }
123 EXPORT_SYMBOL(uuid_parse);
124