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/hex.h> 14 #include <linux/uuid.h> 15 #include <linux/random.h> 16 17 const guid_t guid_null; 18 EXPORT_SYMBOL(guid_null); 19 const uuid_t uuid_null; 20 EXPORT_SYMBOL(uuid_null); 21 22 const u8 guid_index[16] = {3,2,1,0,5,4,7,6,8,9,10,11,12,13,14,15}; 23 const 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 */ 34 void 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 } 42 EXPORT_SYMBOL(generate_random_uuid); 43 44 void 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 } 52 EXPORT_SYMBOL(generate_random_guid); 53 54 static void __uuid_gen_common(__u8 b[16]) 55 { 56 get_random_bytes(b, 16); 57 /* reversion 0b10 */ 58 b[8] = (b[8] & 0x3F) | 0x80; 59 } 60 61 void 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 } 67 EXPORT_SYMBOL_GPL(guid_gen); 68 69 void 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 } 75 EXPORT_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 */ 89 bool 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 } 104 EXPORT_SYMBOL(uuid_is_valid); 105 106 static 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 } 123 124 int guid_parse(const char *uuid, guid_t *u) 125 { 126 return __uuid_parse(uuid, u->b, guid_index); 127 } 128 EXPORT_SYMBOL(guid_parse); 129 130 int uuid_parse(const char *uuid, uuid_t *u) 131 { 132 return __uuid_parse(uuid, u->b, uuid_index); 133 } 134 EXPORT_SYMBOL(uuid_parse); 135