1/*
2 * Universally Unique IDentifier (UUID)
3 * Copyright (c) 2008, Jouni Malinen <j@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
15int 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
50int 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
65int 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
75int 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