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 prandom_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