1 /* 2 * Universally Unique IDentifier (UUID) 3 * Copyright (c) 2008, Jouni Malinen <j (at) w1.fi> 4 * 5 * This software may be distributed under the terms of the BSD license. 6 * See README for more details. 7 */ 8 9 #include "includes.h" 10 11 #include "common.h" 12 #include "crypto/sha256.h" 13 #include "uuid.h" 14 15 int uuid_str2bin(const char *str, u8 *bin) 16 { 17 const char *pos; 18 u8 *opos; 19 20 pos = str; 21 opos = bin; 22 23 if (hexstr2bin(pos, opos, 4)) 24 return -1; 25 pos += 8; 26 opos += 4; 27 28 if (*pos++ != '-' || hexstr2bin(pos, opos, 2)) 29 return -1; 30 pos += 4; 31 opos += 2; 32 33 if (*pos++ != '-' || hexstr2bin(pos, opos, 2)) 34 return -1; 35 pos += 4; 36 opos += 2; 37 38 if (*pos++ != '-' || hexstr2bin(pos, opos, 2)) 39 return -1; 40 pos += 4; 41 opos += 2; 42 43 if (*pos++ != '-' || hexstr2bin(pos, opos, 6)) 44 return -1; 45 46 return 0; 47 } 48 49 50 int uuid_bin2str(const u8 *bin, char *str, size_t max_len) 51 { 52 int len; 53 len = os_snprintf(str, max_len, "%02x%02x%02x%02x-%02x%02x-%02x%02x-" 54 "%02x%02x-%02x%02x%02x%02x%02x%02x", 55 bin[0], bin[1], bin[2], bin[3], 56 bin[4], bin[5], bin[6], bin[7], 57 bin[8], bin[9], bin[10], bin[11], 58 bin[12], bin[13], bin[14], bin[15]); 59 if (os_snprintf_error(max_len, len)) 60 return -1; 61 return 0; 62 } 63 64 65 int is_nil_uuid(const u8 *uuid) 66 { 67 int i; 68 for (i = 0; i < UUID_LEN; i++) 69 if (uuid[i]) 70 return 0; 71 return 1; 72 } 73 74 75 int uuid_random(u8 *uuid) 76 { 77 struct os_time t; 78 u8 hash[SHA256_MAC_LEN]; 79 80 /* Use HMAC-SHA256 and timestamp as context to avoid exposing direct 81 * os_get_random() output in the UUID field. */ 82 os_get_time(&t); 83 if (os_get_random(uuid, UUID_LEN) < 0 || 84 hmac_sha256(uuid, UUID_LEN, (const u8 *) &t, sizeof(t), hash) < 0) 85 return -1; 86 87 os_memcpy(uuid, hash, UUID_LEN); 88 89 /* Version: 4 = random */ 90 uuid[6] = (4 << 4) | (uuid[6] & 0x0f); 91 92 /* Variant specified in RFC 4122 */ 93 uuid[8] = 0x80 | (uuid[8] & 0x3f); 94 95 return 0; 96 } 97
