1/* 2 * Copyright (C) 2004-2007, 2009, 2013, 2014 Internet Systems Consortium, Inc. ("ISC") 3 * Copyright (C) 2003 Internet Software Consortium. 4 * 5 * Permission to use, copy, modify, and/or distribute this software for any 6 * purpose with or without fee is hereby granted, provided that the above 7 * copyright notice and this permission notice appear in all copies. 8 * 9 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH 10 * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY 11 * AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT, 12 * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM 13 * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE 14 * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR 15 * PERFORMANCE OF THIS SOFTWARE. 16 */ 17 18/* $Id: hash.c,v 1.16 2009/09/01 00:22:28 jinmei Exp $ */ 19 20/*! \file 21 * Some portion of this code was derived from universal hash function 22 * libraries of Rice University. 23\section license UH Universal Hashing Library 24 25Copyright ((c)) 2002, Rice University 26All rights reserved. 27 28Redistribution and use in source and binary forms, with or without 29modification, are permitted provided that the following conditions are 30met: 31 32 * Redistributions of source code must retain the above copyright 33 notice, this list of conditions and the following disclaimer. 34 35 * Redistributions in binary form must reproduce the above 36 copyright notice, this list of conditions and the following 37 disclaimer in the documentation and/or other materials provided 38 with the distribution. 39 40 * Neither the name of Rice University (RICE) nor the names of its 41 contributors may be used to endorse or promote products derived 42 from this software without specific prior written permission. 43 44 45This software is provided by RICE and the contributors on an "as is" 46basis, without any representations or warranties of any kind, express 47or implied including, but not limited to, representations or 48warranties of non-infringement, merchantability or fitness for a 49particular purpose. In no event shall RICE or contributors be liable 50for any direct, indirect, incidental, special, exemplary, or 51consequential damages (including, but not limited to, procurement of 52substitute goods or services; loss of use, data, or profits; or 53business interruption) however caused and on any theory of liability, 54whether in contract, strict liability, or tort (including negligence 55or otherwise) arising in any way out of the use of this software, even 56if advised of the possibility of such damage. 57*/ 58 59#include <config.h> 60 61#include <isc/entropy.h> 62#include <isc/hash.h> 63#include <isc/mem.h> 64#include <isc/magic.h> 65#include <isc/mutex.h> 66#include <isc/once.h> 67#include <isc/random.h> 68#include <isc/refcount.h> 69#include <isc/string.h> 70#include <isc/util.h> 71 72#define HASH_MAGIC ISC_MAGIC('H', 'a', 's', 'h') 73#define VALID_HASH(h) ISC_MAGIC_VALID((h), HASH_MAGIC) 74 75/*% 76 * A large 32-bit prime number that specifies the range of the hash output. 77 */ 78#define PRIME32 0xFFFFFFFB /* 2^32 - 5 */ 79 80/*@{*/ 81/*% 82 * Types of random seed and hash accumulator. Perhaps they can be system 83 * dependent. 84 */ 85typedef isc_uint32_t hash_accum_t; 86typedef isc_uint16_t hash_random_t; 87/*@}*/ 88 89/*% isc hash structure */ 90struct isc_hash { 91 unsigned int magic; 92 isc_mem_t *mctx; 93 isc_mutex_t lock; 94 isc_boolean_t initialized; 95 isc_refcount_t refcnt; 96 isc_entropy_t *entropy; /*%< entropy source */ 97 size_t limit; /*%< upper limit of key length */ 98 size_t vectorlen; /*%< size of the vector below */ 99 hash_random_t *rndvector; /*%< random vector for universal hashing */ 100}; 101 102static isc_mutex_t createlock; 103static isc_once_t once = ISC_ONCE_INIT; 104static isc_hash_t *hash = NULL; 105 106static unsigned char maptolower[] = { 107 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 108 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, 109 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 110 0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f, 111 0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27, 112 0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f, 113 0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 114 0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0x3e, 0x3f, 115 0x40, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67, 116 0x68, 0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f, 117 0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77, 118 0x78, 0x79, 0x7a, 0x5b, 0x5c, 0x5d, 0x5e, 0x5f, 119 0x60, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67, 120 0x68, 0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f, 121 0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77, 122 0x78, 0x79, 0x7a, 0x7b, 0x7c, 0x7d, 0x7e, 0x7f, 123 0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87, 124 0x88, 0x89, 0x8a, 0x8b, 0x8c, 0x8d, 0x8e, 0x8f, 125 0x90, 0x91, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 126 0x98, 0x99, 0x9a, 0x9b, 0x9c, 0x9d, 0x9e, 0x9f, 127 0xa0, 0xa1, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa7, 128 0xa8, 0xa9, 0xaa, 0xab, 0xac, 0xad, 0xae, 0xaf, 129 0xb0, 0xb1, 0xb2, 0xb3, 0xb4, 0xb5, 0xb6, 0xb7, 130 0xb8, 0xb9, 0xba, 0xbb, 0xbc, 0xbd, 0xbe, 0xbf, 131 0xc0, 0xc1, 0xc2, 0xc3, 0xc4, 0xc5, 0xc6, 0xc7, 132 0xc8, 0xc9, 0xca, 0xcb, 0xcc, 0xcd, 0xce, 0xcf, 133 0xd0, 0xd1, 0xd2, 0xd3, 0xd4, 0xd5, 0xd6, 0xd7, 134 0xd8, 0xd9, 0xda, 0xdb, 0xdc, 0xdd, 0xde, 0xdf, 135 0xe0, 0xe1, 0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7, 136 0xe8, 0xe9, 0xea, 0xeb, 0xec, 0xed, 0xee, 0xef, 137 0xf0, 0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 138 0xf8, 0xf9, 0xfa, 0xfb, 0xfc, 0xfd, 0xfe, 0xff 139}; 140 141isc_result_t 142isc_hash_ctxcreate(isc_mem_t *mctx, isc_entropy_t *entropy, 143 size_t limit, isc_hash_t **hctxp) 144{ 145 isc_result_t result; 146 isc_hash_t *hctx; 147 size_t vlen; 148 hash_random_t *rv; 149 hash_accum_t overflow_limit; 150 151 REQUIRE(mctx != NULL); 152 REQUIRE(hctxp != NULL && *hctxp == NULL); 153 154 /* 155 * Overflow check. Since our implementation only does a modulo 156 * operation at the last stage of hash calculation, the accumulator 157 * must not overflow. 158 */ 159 overflow_limit = 160 1 << (((sizeof(hash_accum_t) - sizeof(hash_random_t))) * 8); 161 if (overflow_limit < (limit + 1) * 0xff) 162 return (ISC_R_RANGE); 163 164 hctx = isc_mem_get(mctx, sizeof(isc_hash_t)); 165 if (hctx == NULL) 166 return (ISC_R_NOMEMORY); 167 168 vlen = sizeof(hash_random_t) * (limit + 1); 169 rv = isc_mem_get(mctx, vlen); 170 if (rv == NULL) { 171 result = ISC_R_NOMEMORY; 172 goto errout; 173 } 174 175 /* 176 * We need a lock. 177 */ 178 result = isc_mutex_init(&hctx->lock); 179 if (result != ISC_R_SUCCESS) 180 goto errout; 181 182 /* 183 * From here down, no failures will/can occur. 184 */ 185 hctx->magic = HASH_MAGIC; 186 hctx->mctx = NULL; 187 isc_mem_attach(mctx, &hctx->mctx); 188 hctx->initialized = ISC_FALSE; 189 result = isc_refcount_init(&hctx->refcnt, 1); 190 if (result != ISC_R_SUCCESS) 191 goto cleanup_lock; 192 hctx->entropy = NULL; 193 hctx->limit = limit; 194 hctx->vectorlen = vlen; 195 hctx->rndvector = rv; 196 197#ifdef BIND9 198 if (entropy != NULL) 199 isc_entropy_attach(entropy, &hctx->entropy); 200#else 201 UNUSED(entropy); 202#endif 203 204 *hctxp = hctx; 205 return (ISC_R_SUCCESS); 206 207 cleanup_lock: 208 DESTROYLOCK(&hctx->lock); 209 errout: 210 isc_mem_put(mctx, hctx, sizeof(isc_hash_t)); 211 if (rv != NULL) 212 isc_mem_put(mctx, rv, vlen); 213 214 return (result); 215} 216 217static void 218initialize_lock(void) { 219 RUNTIME_CHECK(isc_mutex_init(&createlock) == ISC_R_SUCCESS); 220} 221 222isc_result_t 223isc_hash_create(isc_mem_t *mctx, isc_entropy_t *entropy, size_t limit) { 224 isc_result_t result = ISC_R_SUCCESS; 225 226 REQUIRE(mctx != NULL); 227 INSIST(hash == NULL); 228 229 RUNTIME_CHECK(isc_once_do(&once, initialize_lock) == ISC_R_SUCCESS); 230 231 LOCK(&createlock); 232 233 if (hash == NULL) 234 result = isc_hash_ctxcreate(mctx, entropy, limit, &hash); 235 236 UNLOCK(&createlock); 237 238 return (result); 239} 240 241void 242isc_hash_ctxinit(isc_hash_t *hctx) { 243 LOCK(&hctx->lock); 244 245 if (hctx->initialized == ISC_TRUE) 246 goto out; 247 248 if (hctx->entropy) { 249#ifdef BIND9 250 isc_result_t result; 251 252 result = isc_entropy_getdata(hctx->entropy, 253 hctx->rndvector, 254 (unsigned int)hctx->vectorlen, 255 NULL, 0); 256 INSIST(result == ISC_R_SUCCESS); 257#else 258 INSIST(0); 259#endif 260 } else { 261 isc_uint32_t pr; 262 size_t i, copylen; 263 unsigned char *p; 264 265 p = (unsigned char *)hctx->rndvector; 266 for (i = 0; i < hctx->vectorlen; i += copylen, p += copylen) { 267 isc_random_get(&pr); 268 if (i + sizeof(pr) <= hctx->vectorlen) 269 copylen = sizeof(pr); 270 else 271 copylen = hctx->vectorlen - i; 272 273 memmove(p, &pr, copylen); 274 } 275 INSIST(p == (unsigned char *)hctx->rndvector + 276 hctx->vectorlen); 277 } 278 279 hctx->initialized = ISC_TRUE; 280 281 out: 282 UNLOCK(&hctx->lock); 283} 284 285void 286isc_hash_init() { 287 INSIST(hash != NULL && VALID_HASH(hash)); 288 289 isc_hash_ctxinit(hash); 290} 291 292void 293isc_hash_ctxattach(isc_hash_t *hctx, isc_hash_t **hctxp) { 294 REQUIRE(VALID_HASH(hctx)); 295 REQUIRE(hctxp != NULL && *hctxp == NULL); 296 297 isc_refcount_increment(&hctx->refcnt, NULL); 298 *hctxp = hctx; 299} 300 301static void 302destroy(isc_hash_t **hctxp) { 303 isc_hash_t *hctx; 304 isc_mem_t *mctx; 305 unsigned char canary0[4], canary1[4]; 306 307 REQUIRE(hctxp != NULL && *hctxp != NULL); 308 hctx = *hctxp; 309 *hctxp = NULL; 310 311 LOCK(&hctx->lock); 312 313 isc_refcount_destroy(&hctx->refcnt); 314 315 mctx = hctx->mctx; 316#ifdef BIND9 317 if (hctx->entropy != NULL) 318 isc_entropy_detach(&hctx->entropy); 319#endif 320 if (hctx->rndvector != NULL) 321 isc_mem_put(mctx, hctx->rndvector, hctx->vectorlen); 322 323 UNLOCK(&hctx->lock); 324 325 DESTROYLOCK(&hctx->lock); 326 327 memmove(canary0, hctx + 1, sizeof(canary0)); 328 memset(hctx, 0, sizeof(isc_hash_t)); 329 memmove(canary1, hctx + 1, sizeof(canary1)); 330 INSIST(memcmp(canary0, canary1, sizeof(canary0)) == 0); 331 isc_mem_put(mctx, hctx, sizeof(isc_hash_t)); 332 isc_mem_detach(&mctx); 333} 334 335void 336isc_hash_ctxdetach(isc_hash_t **hctxp) { 337 isc_hash_t *hctx; 338 unsigned int refs; 339 340 REQUIRE(hctxp != NULL && VALID_HASH(*hctxp)); 341 hctx = *hctxp; 342 343 isc_refcount_decrement(&hctx->refcnt, &refs); 344 if (refs == 0) 345 destroy(&hctx); 346 347 *hctxp = NULL; 348} 349 350void 351isc_hash_destroy() { 352 unsigned int refs; 353 354 INSIST(hash != NULL && VALID_HASH(hash)); 355 356 isc_refcount_decrement(&hash->refcnt, &refs); 357 INSIST(refs == 0); 358 359 destroy(&hash); 360} 361 362static inline unsigned int 363hash_calc(isc_hash_t *hctx, const unsigned char *key, unsigned int keylen, 364 isc_boolean_t case_sensitive) 365{ 366 hash_accum_t partial_sum = 0; 367 hash_random_t *p = hctx->rndvector; 368 unsigned int i = 0; 369 370 /* Make it sure that the hash context is initialized. */ 371 if (hctx->initialized == ISC_FALSE) 372 isc_hash_ctxinit(hctx); 373 374 if (case_sensitive) { 375 for (i = 0; i < keylen; i++) 376 partial_sum += key[i] * (hash_accum_t)p[i]; 377 } else { 378 for (i = 0; i < keylen; i++) 379 partial_sum += maptolower[key[i]] * (hash_accum_t)p[i]; 380 } 381 382 partial_sum += p[i]; 383 384 return ((unsigned int)(partial_sum % PRIME32)); 385} 386 387unsigned int 388isc_hash_ctxcalc(isc_hash_t *hctx, const unsigned char *key, 389 unsigned int keylen, isc_boolean_t case_sensitive) 390{ 391 REQUIRE(hctx != NULL && VALID_HASH(hctx)); 392 REQUIRE(keylen <= hctx->limit); 393 394 return (hash_calc(hctx, key, keylen, case_sensitive)); 395} 396 397unsigned int 398isc_hash_calc(const unsigned char *key, unsigned int keylen, 399 isc_boolean_t case_sensitive) 400{ 401 INSIST(hash != NULL && VALID_HASH(hash)); 402 REQUIRE(keylen <= hash->limit); 403 404 return (hash_calc(hash, key, keylen, case_sensitive)); 405} 406