hash.c revision 1.4
1/* $NetBSD: hash.c,v 1.4 2019/09/05 19:32:59 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 http://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/* 15 * 32 bit Fowler/Noll/Vo FNV-1a hash code with modification for BIND 16 */ 17 18#include <config.h> // IWYU pragma: keep 19 20#include <stdbool.h> 21#include <stddef.h> 22#include <inttypes.h> 23#if defined(WIN32) || defined(WIN64) 24#include <malloc.h> 25#endif 26 27#include "isc/hash.h" // IWYU pragma: keep 28#include "isc/likely.h" 29#include "isc/once.h" 30#include "isc/random.h" 31#include "isc/result.h" 32#include "isc/types.h" 33#include "isc/util.h" 34#include "isc/siphash.h" 35#include "isc/string.h" 36 37#include "entropy_private.h" 38 39static uint8_t isc_hash_key[16]; 40static bool hash_initialized = false; 41static isc_once_t isc_hash_once = ISC_ONCE_INIT; 42 43static void 44isc_hash_initialize(void) { 45 uint64_t key[2] = { 0, 1 }; 46#if FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION 47 /* 48 * Set a constant key to help in problem reproduction should 49 * fuzzing find a crash or a hang. 50 */ 51#else 52 isc_entropy_get(key, sizeof(key)); 53#endif 54 memmove(isc_hash_key, key, sizeof(isc_hash_key)); 55 hash_initialized = true; 56} 57 58static uint8_t maptolower[] = { 59 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 60 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, 61 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 62 0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f, 63 0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27, 64 0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f, 65 0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 66 0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0x3e, 0x3f, 67 0x40, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67, 68 0x68, 0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f, 69 0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77, 70 0x78, 0x79, 0x7a, 0x5b, 0x5c, 0x5d, 0x5e, 0x5f, 71 0x60, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67, 72 0x68, 0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f, 73 0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77, 74 0x78, 0x79, 0x7a, 0x7b, 0x7c, 0x7d, 0x7e, 0x7f, 75 0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87, 76 0x88, 0x89, 0x8a, 0x8b, 0x8c, 0x8d, 0x8e, 0x8f, 77 0x90, 0x91, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 78 0x98, 0x99, 0x9a, 0x9b, 0x9c, 0x9d, 0x9e, 0x9f, 79 0xa0, 0xa1, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa7, 80 0xa8, 0xa9, 0xaa, 0xab, 0xac, 0xad, 0xae, 0xaf, 81 0xb0, 0xb1, 0xb2, 0xb3, 0xb4, 0xb5, 0xb6, 0xb7, 82 0xb8, 0xb9, 0xba, 0xbb, 0xbc, 0xbd, 0xbe, 0xbf, 83 0xc0, 0xc1, 0xc2, 0xc3, 0xc4, 0xc5, 0xc6, 0xc7, 84 0xc8, 0xc9, 0xca, 0xcb, 0xcc, 0xcd, 0xce, 0xcf, 85 0xd0, 0xd1, 0xd2, 0xd3, 0xd4, 0xd5, 0xd6, 0xd7, 86 0xd8, 0xd9, 0xda, 0xdb, 0xdc, 0xdd, 0xde, 0xdf, 87 0xe0, 0xe1, 0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7, 88 0xe8, 0xe9, 0xea, 0xeb, 0xec, 0xed, 0xee, 0xef, 89 0xf0, 0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 90 0xf8, 0xf9, 0xfa, 0xfb, 0xfc, 0xfd, 0xfe, 0xff 91}; 92 93const void * 94isc_hash_get_initializer(void) { 95 if (ISC_UNLIKELY(!hash_initialized)) { 96 RUNTIME_CHECK(isc_once_do(&isc_hash_once, 97 isc_hash_initialize) 98 == ISC_R_SUCCESS); 99 } 100 101 return (isc_hash_key); 102} 103 104void 105isc_hash_set_initializer(const void *initializer) { 106 REQUIRE(initializer != NULL); 107 108 /* 109 * Ensure that isc_hash_initialize() is not called after 110 * isc_hash_set_initializer() is called. 111 */ 112 if (ISC_UNLIKELY(!hash_initialized)) { 113 RUNTIME_CHECK(isc_once_do(&isc_hash_once, 114 isc_hash_initialize) 115 == ISC_R_SUCCESS); 116 } 117 118 memmove(isc_hash_key, initializer, sizeof(isc_hash_key)); 119} 120 121uint64_t 122isc_hash_function(const void *data, 123 const size_t length, 124 const bool case_sensitive) 125{ 126 uint64_t hval; 127 128 REQUIRE(length == 0 || data != NULL); 129 130 RUNTIME_CHECK(isc_once_do(&isc_hash_once, 131 isc_hash_initialize) == ISC_R_SUCCESS); 132 133 if (case_sensitive) { 134 isc_siphash24(isc_hash_key, data, length, (uint8_t *)&hval); 135 } else { 136 uint8_t input[1024]; 137 REQUIRE(length <= 1024); 138 for (unsigned int i = 0; i < length; i++) { 139 input[i] = maptolower[((const uint8_t *)data)[i]]; 140 } 141 isc_siphash24(isc_hash_key, input, length, (uint8_t *)&hval); 142 } 143 144 return (hval); 145} 146