hash.c revision 1.6 
1/*	$NetBSD: hash.c,v 1.6 2021/02/19 16:42:19 christos Exp $	*/
2
3/*
4 * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
5 *
6 * This Source Code Form is subject to the terms of the Mozilla Public
7 * License, v. 2.0. If a copy of the MPL was not distributed with this
8 * file, you can obtain one at https://mozilla.org/MPL/2.0/.
9 *
10 * See the COPYRIGHT file distributed with this work for additional
11 * information regarding copyright ownership.
12 */
13
14#include <inttypes.h>
15#include <stdbool.h>
16#include <stddef.h>
17#if defined(WIN32) || defined(WIN64)
18#include <malloc.h>
19#endif /* if defined(WIN32) || defined(WIN64) */
20
21#include "entropy_private.h"
22#include "isc/hash.h" /* IWYU pragma: keep */
23#include "isc/likely.h"
24#include "isc/once.h"
25#include "isc/random.h"
26#include "isc/result.h"
27#include "isc/siphash.h"
28#include "isc/string.h"
29#include "isc/types.h"
30#include "isc/util.h"
31
32static uint8_t isc_hash_key[16];
33static uint8_t isc_hash32_key[8];
34static bool hash_initialized = false;
35static isc_once_t isc_hash_once = ISC_ONCE_INIT;
36
37static void
38isc_hash_initialize(void) {
39	/*
40	 * Set a constant key to help in problem reproduction should
41	 * fuzzing find a crash or a hang.
42	 */
43	uint64_t key[2] = { 0, 1 };
44#if !FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
45	isc_entropy_get(key, sizeof(key));
46#endif /* if FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION */
47	memmove(isc_hash_key, key, sizeof(isc_hash_key));
48#if !FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
49	isc_entropy_get(key, sizeof(key));
50#endif /* if FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION */
51	memmove(isc_hash32_key, key, sizeof(isc_hash32_key));
52	hash_initialized = true;
53}
54
55static uint8_t maptolower[] = {
56	0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b,
57	0x0c, 0x0d, 0x0e, 0x0f, 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17,
58	0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f, 0x20, 0x21, 0x22, 0x23,
59	0x24, 0x25, 0x26, 0x27, 0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f,
60	0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3a, 0x3b,
61	0x3c, 0x3d, 0x3e, 0x3f, 0x40, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67,
62	0x68, 0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f, 0x70, 0x71, 0x72, 0x73,
63	0x74, 0x75, 0x76, 0x77, 0x78, 0x79, 0x7a, 0x5b, 0x5c, 0x5d, 0x5e, 0x5f,
64	0x60, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69, 0x6a, 0x6b,
65	0x6c, 0x6d, 0x6e, 0x6f, 0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77,
66	0x78, 0x79, 0x7a, 0x7b, 0x7c, 0x7d, 0x7e, 0x7f, 0x80, 0x81, 0x82, 0x83,
67	0x84, 0x85, 0x86, 0x87, 0x88, 0x89, 0x8a, 0x8b, 0x8c, 0x8d, 0x8e, 0x8f,
68	0x90, 0x91, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98, 0x99, 0x9a, 0x9b,
69	0x9c, 0x9d, 0x9e, 0x9f, 0xa0, 0xa1, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa7,
70	0xa8, 0xa9, 0xaa, 0xab, 0xac, 0xad, 0xae, 0xaf, 0xb0, 0xb1, 0xb2, 0xb3,
71	0xb4, 0xb5, 0xb6, 0xb7, 0xb8, 0xb9, 0xba, 0xbb, 0xbc, 0xbd, 0xbe, 0xbf,
72	0xc0, 0xc1, 0xc2, 0xc3, 0xc4, 0xc5, 0xc6, 0xc7, 0xc8, 0xc9, 0xca, 0xcb,
73	0xcc, 0xcd, 0xce, 0xcf, 0xd0, 0xd1, 0xd2, 0xd3, 0xd4, 0xd5, 0xd6, 0xd7,
74	0xd8, 0xd9, 0xda, 0xdb, 0xdc, 0xdd, 0xde, 0xdf, 0xe0, 0xe1, 0xe2, 0xe3,
75	0xe4, 0xe5, 0xe6, 0xe7, 0xe8, 0xe9, 0xea, 0xeb, 0xec, 0xed, 0xee, 0xef,
76	0xf0, 0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8, 0xf9, 0xfa, 0xfb,
77	0xfc, 0xfd, 0xfe, 0xff
78};
79
80const void *
81isc_hash_get_initializer(void) {
82	if (ISC_UNLIKELY(!hash_initialized)) {
83		RUNTIME_CHECK(
84			isc_once_do(&isc_hash_once, isc_hash_initialize) ==
85			ISC_R_SUCCESS);
86	}
87
88	return (isc_hash_key);
89}
90
91void
92isc_hash_set_initializer(const void *initializer) {
93	REQUIRE(initializer != NULL);
94
95	/*
96	 * Ensure that isc_hash_initialize() is not called after
97	 * isc_hash_set_initializer() is called.
98	 */
99	if (ISC_UNLIKELY(!hash_initialized)) {
100		RUNTIME_CHECK(
101			isc_once_do(&isc_hash_once, isc_hash_initialize) ==
102			ISC_R_SUCCESS);
103	}
104
105	memmove(isc_hash_key, initializer, sizeof(isc_hash_key));
106}
107
108uint64_t
109isc_hash64(const void *data, const size_t length, const bool case_sensitive) {
110	uint64_t hval;
111
112	REQUIRE(length == 0 || data != NULL);
113
114	RUNTIME_CHECK(isc_once_do(&isc_hash_once, isc_hash_initialize) ==
115		      ISC_R_SUCCESS);
116
117	if (case_sensitive) {
118		isc_siphash24(isc_hash_key, data, length, (uint8_t *)&hval);
119	} else {
120		uint8_t input[1024];
121		REQUIRE(length <= 1024);
122		for (unsigned int i = 0; i < length; i++) {
123			input[i] = maptolower[((const uint8_t *)data)[i]];
124		}
125		isc_siphash24(isc_hash_key, input, length, (uint8_t *)&hval);
126	}
127
128	return (hval);
129}
130
131uint32_t
132isc_hash32(const void *data, const size_t length, const bool case_sensitive) {
133	uint32_t hval;
134
135	REQUIRE(length == 0 || data != NULL);
136
137	RUNTIME_CHECK(isc_once_do(&isc_hash_once, isc_hash_initialize) ==
138		      ISC_R_SUCCESS);
139
140	if (case_sensitive) {
141		isc_halfsiphash24(isc_hash_key, data, length, (uint8_t *)&hval);
142	} else {
143		uint8_t input[1024];
144		REQUIRE(length <= 1024);
145		for (unsigned int i = 0; i < length; i++) {
146			input[i] = maptolower[((const uint8_t *)data)[i]];
147		}
148		isc_halfsiphash24(isc_hash_key, input, length,
149				  (uint8_t *)&hval);
150	}
151
152	return (hval);
153}
154