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 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 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 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 */ 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 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 } 112 113 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); 118 119 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