1 /* 2 * Unified UUID/GUID definition 3 * 4 * Copyright (C) 2009, 2016 Intel Corp. 5 * Huang Ying <ying.huang@intel.com> 6 * 7 * This program is free software; you can redistribute it and/or 8 * modify it under the terms of the GNU General Public License version 9 * 2 as published by the Free Software Foundation; 10 * 11 * This program is distributed in the hope that it will be useful, 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 * GNU General Public License for more details. 15 */ 16 17 #include <linux/kernel.h> 18 #include <linux/ctype.h> 19 #include <linux/errno.h> 20 #include <linux/export.h> 21 #include <linux/uuid.h> 22 #include <linux/random.h> 23 24 const u8 uuid_le_index[16] = {3,2,1,0,5,4,7,6,8,9,10,11,12,13,14,15}; 25 EXPORT_SYMBOL(uuid_le_index); 26 const u8 uuid_be_index[16] = {0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15}; 27 EXPORT_SYMBOL(uuid_be_index); 28 29 /*************************************************************** 30 * Random UUID interface 31 * 32 * Used here for a Boot ID, but can be useful for other kernel 33 * drivers. 34 ***************************************************************/ 35 36 /* 37 * Generate random UUID 38 */ 39 void generate_random_uuid(unsigned char uuid[16]) 40 { 41 get_random_bytes(uuid, 16); 42 /* Set UUID version to 4 --- truly random generation */ 43 uuid[6] = (uuid[6] & 0x0F) | 0x40; 44 /* Set the UUID variant to DCE */ 45 uuid[8] = (uuid[8] & 0x3F) | 0x80; 46 } 47 EXPORT_SYMBOL(generate_random_uuid); 48 49 static void __uuid_gen_common(__u8 b[16]) 50 { 51 prandom_bytes(b, 16); 52 /* reversion 0b10 */ 53 b[8] = (b[8] & 0x3F) | 0x80; 54 } 55 56 void uuid_le_gen(uuid_le *lu) 57 { 58 __uuid_gen_common(lu->b); 59 /* version 4 : random generation */ 60 lu->b[7] = (lu->b[7] & 0x0F) | 0x40; 61 } 62 EXPORT_SYMBOL_GPL(uuid_le_gen); 63 64 void uuid_be_gen(uuid_be *bu) 65 { 66 __uuid_gen_common(bu->b); 67 /* version 4 : random generation */ 68 bu->b[6] = (bu->b[6] & 0x0F) | 0x40; 69 } 70 EXPORT_SYMBOL_GPL(uuid_be_gen); 71 72 /** 73 * uuid_is_valid - checks if UUID string valid 74 * @uuid: UUID string to check 75 * 76 * Description: 77 * It checks if the UUID string is following the format: 78 * xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx 79 * where x is a hex digit. 80 * 81 * Return: true if input is valid UUID string. 82 */ 83 bool uuid_is_valid(const char *uuid) 84 { 85 unsigned int i; 86 87 for (i = 0; i < UUID_STRING_LEN; i++) { 88 if (i == 8 || i == 13 || i == 18 || i == 23) { 89 if (uuid[i] != '-') 90 return false; 91 } else if (!isxdigit(uuid[i])) { 92 return false; 93 } 94 } 95 96 return true; 97 } 98 EXPORT_SYMBOL(uuid_is_valid); 99 100 static int __uuid_to_bin(const char *uuid, __u8 b[16], const u8 ei[16]) 101 { 102 static const u8 si[16] = {0,2,4,6,9,11,14,16,19,21,24,26,28,30,32,34}; 103 unsigned int i; 104 105 if (!uuid_is_valid(uuid)) 106 return -EINVAL; 107 108 for (i = 0; i < 16; i++) { 109 int hi = hex_to_bin(uuid[si[i] + 0]); 110 int lo = hex_to_bin(uuid[si[i] + 1]); 111 112 b[ei[i]] = (hi << 4) | lo; 113 } 114 115 return 0; 116 } 117 118 int uuid_le_to_bin(const char *uuid, uuid_le *u) 119 { 120 return __uuid_to_bin(uuid, u->b, uuid_le_index); 121 } 122 EXPORT_SYMBOL(uuid_le_to_bin); 123 124 int uuid_be_to_bin(const char *uuid, uuid_be *u) 125 { 126 return __uuid_to_bin(uuid, u->b, uuid_be_index); 127 } 128 EXPORT_SYMBOL(uuid_be_to_bin); 129