1/* 2 * Copyright 1995-2023 The OpenSSL Project Authors. All Rights Reserved. 3 * 4 * Licensed under the Apache License 2.0 (the "License"). You may not use 5 * this file except in compliance with the License. You can obtain a copy 6 * in the file LICENSE in the source distribution or at 7 * https://www.openssl.org/source/license.html 8 */ 9 10#include <stdio.h> 11#include <string.h> 12#include <stdlib.h> 13#include <openssl/crypto.h> 14#include <openssl/lhash.h> 15#include <openssl/err.h> 16#include "crypto/ctype.h" 17#include "crypto/lhash.h" 18#include "lhash_local.h" 19 20/* 21 * A hashing implementation that appears to be based on the linear hashing 22 * algorithm: 23 * https://en.wikipedia.org/wiki/Linear_hashing 24 * 25 * Litwin, Witold (1980), "Linear hashing: A new tool for file and table 26 * addressing", Proc. 6th Conference on Very Large Databases: 212-223 27 * https://hackthology.com/pdfs/Litwin-1980-Linear_Hashing.pdf 28 * 29 * From the Wikipedia article "Linear hashing is used in the BDB Berkeley 30 * database system, which in turn is used by many software systems such as 31 * OpenLDAP, using a C implementation derived from the CACM article and first 32 * published on the Usenet in 1988 by Esmond Pitt." 33 * 34 * The CACM paper is available here: 35 * https://pdfs.semanticscholar.org/ff4d/1c5deca6269cc316bfd952172284dbf610ee.pdf 36 */ 37 38#undef MIN_NODES 39#define MIN_NODES 16 40#define UP_LOAD (2*LH_LOAD_MULT) /* load times 256 (default 2) */ 41#define DOWN_LOAD (LH_LOAD_MULT) /* load times 256 (default 1) */ 42 43static int expand(OPENSSL_LHASH *lh); 44static void contract(OPENSSL_LHASH *lh); 45static OPENSSL_LH_NODE **getrn(OPENSSL_LHASH *lh, const void *data, unsigned long *rhash); 46 47OPENSSL_LHASH *OPENSSL_LH_new(OPENSSL_LH_HASHFUNC h, OPENSSL_LH_COMPFUNC c) 48{ 49 OPENSSL_LHASH *ret; 50 51 if ((ret = OPENSSL_zalloc(sizeof(*ret))) == NULL) { 52 /* 53 * Do not set the error code, because the ERR code uses LHASH 54 * and we want to avoid possible endless error loop. 55 * ERR_raise(ERR_LIB_CRYPTO, ERR_R_MALLOC_FAILURE); 56 */ 57 return NULL; 58 } 59 if ((ret->b = OPENSSL_zalloc(sizeof(*ret->b) * MIN_NODES)) == NULL) 60 goto err; 61 ret->comp = ((c == NULL) ? (OPENSSL_LH_COMPFUNC)strcmp : c); 62 ret->hash = ((h == NULL) ? (OPENSSL_LH_HASHFUNC)OPENSSL_LH_strhash : h); 63 ret->num_nodes = MIN_NODES / 2; 64 ret->num_alloc_nodes = MIN_NODES; 65 ret->pmax = MIN_NODES / 2; 66 ret->up_load = UP_LOAD; 67 ret->down_load = DOWN_LOAD; 68 return ret; 69 70err: 71 OPENSSL_free(ret->b); 72 OPENSSL_free(ret); 73 return NULL; 74} 75 76void OPENSSL_LH_free(OPENSSL_LHASH *lh) 77{ 78 if (lh == NULL) 79 return; 80 81 OPENSSL_LH_flush(lh); 82 OPENSSL_free(lh->b); 83 OPENSSL_free(lh); 84} 85 86void OPENSSL_LH_flush(OPENSSL_LHASH *lh) 87{ 88 unsigned int i; 89 OPENSSL_LH_NODE *n, *nn; 90 91 if (lh == NULL) 92 return; 93 94 for (i = 0; i < lh->num_nodes; i++) { 95 n = lh->b[i]; 96 while (n != NULL) { 97 nn = n->next; 98 OPENSSL_free(n); 99 n = nn; 100 } 101 lh->b[i] = NULL; 102 } 103 104 lh->num_items = 0; 105} 106 107void *OPENSSL_LH_insert(OPENSSL_LHASH *lh, void *data) 108{ 109 unsigned long hash; 110 OPENSSL_LH_NODE *nn, **rn; 111 void *ret; 112 113 lh->error = 0; 114 if ((lh->up_load <= (lh->num_items * LH_LOAD_MULT / lh->num_nodes)) && !expand(lh)) 115 return NULL; /* 'lh->error++' already done in 'expand' */ 116 117 rn = getrn(lh, data, &hash); 118 119 if (*rn == NULL) { 120 if ((nn = OPENSSL_malloc(sizeof(*nn))) == NULL) { 121 lh->error++; 122 return NULL; 123 } 124 nn->data = data; 125 nn->next = NULL; 126 nn->hash = hash; 127 *rn = nn; 128 ret = NULL; 129 lh->num_items++; 130 } else { /* replace same key */ 131 ret = (*rn)->data; 132 (*rn)->data = data; 133 } 134 return ret; 135} 136 137void *OPENSSL_LH_delete(OPENSSL_LHASH *lh, const void *data) 138{ 139 unsigned long hash; 140 OPENSSL_LH_NODE *nn, **rn; 141 void *ret; 142 143 lh->error = 0; 144 rn = getrn(lh, data, &hash); 145 146 if (*rn == NULL) { 147 return NULL; 148 } else { 149 nn = *rn; 150 *rn = nn->next; 151 ret = nn->data; 152 OPENSSL_free(nn); 153 } 154 155 lh->num_items--; 156 if ((lh->num_nodes > MIN_NODES) && 157 (lh->down_load >= (lh->num_items * LH_LOAD_MULT / lh->num_nodes))) 158 contract(lh); 159 160 return ret; 161} 162 163void *OPENSSL_LH_retrieve(OPENSSL_LHASH *lh, const void *data) 164{ 165 unsigned long hash; 166 OPENSSL_LH_NODE **rn; 167 168 if (lh->error != 0) 169 lh->error = 0; 170 171 rn = getrn(lh, data, &hash); 172 173 return *rn == NULL ? NULL : (*rn)->data; 174} 175 176static void doall_util_fn(OPENSSL_LHASH *lh, int use_arg, 177 OPENSSL_LH_DOALL_FUNC func, 178 OPENSSL_LH_DOALL_FUNCARG func_arg, void *arg) 179{ 180 int i; 181 OPENSSL_LH_NODE *a, *n; 182 183 if (lh == NULL) 184 return; 185 186 /* 187 * reverse the order so we search from 'top to bottom' We were having 188 * memory leaks otherwise 189 */ 190 for (i = lh->num_nodes - 1; i >= 0; i--) { 191 a = lh->b[i]; 192 while (a != NULL) { 193 n = a->next; 194 if (use_arg) 195 func_arg(a->data, arg); 196 else 197 func(a->data); 198 a = n; 199 } 200 } 201} 202 203void OPENSSL_LH_doall(OPENSSL_LHASH *lh, OPENSSL_LH_DOALL_FUNC func) 204{ 205 doall_util_fn(lh, 0, func, (OPENSSL_LH_DOALL_FUNCARG)0, NULL); 206} 207 208void OPENSSL_LH_doall_arg(OPENSSL_LHASH *lh, OPENSSL_LH_DOALL_FUNCARG func, void *arg) 209{ 210 doall_util_fn(lh, 1, (OPENSSL_LH_DOALL_FUNC)0, func, arg); 211} 212 213static int expand(OPENSSL_LHASH *lh) 214{ 215 OPENSSL_LH_NODE **n, **n1, **n2, *np; 216 unsigned int p, pmax, nni, j; 217 unsigned long hash; 218 219 nni = lh->num_alloc_nodes; 220 p = lh->p; 221 pmax = lh->pmax; 222 if (p + 1 >= pmax) { 223 j = nni * 2; 224 n = OPENSSL_realloc(lh->b, sizeof(OPENSSL_LH_NODE *) * j); 225 if (n == NULL) { 226 lh->error++; 227 return 0; 228 } 229 lh->b = n; 230 memset(n + nni, 0, sizeof(*n) * (j - nni)); 231 lh->pmax = nni; 232 lh->num_alloc_nodes = j; 233 lh->p = 0; 234 } else { 235 lh->p++; 236 } 237 238 lh->num_nodes++; 239 n1 = &(lh->b[p]); 240 n2 = &(lh->b[p + pmax]); 241 *n2 = NULL; 242 243 for (np = *n1; np != NULL;) { 244 hash = np->hash; 245 if ((hash % nni) != p) { /* move it */ 246 *n1 = (*n1)->next; 247 np->next = *n2; 248 *n2 = np; 249 } else 250 n1 = &((*n1)->next); 251 np = *n1; 252 } 253 254 return 1; 255} 256 257static void contract(OPENSSL_LHASH *lh) 258{ 259 OPENSSL_LH_NODE **n, *n1, *np; 260 261 np = lh->b[lh->p + lh->pmax - 1]; 262 lh->b[lh->p + lh->pmax - 1] = NULL; /* 24/07-92 - eay - weird but :-( */ 263 if (lh->p == 0) { 264 n = OPENSSL_realloc(lh->b, 265 (unsigned int)(sizeof(OPENSSL_LH_NODE *) * lh->pmax)); 266 if (n == NULL) { 267 /* fputs("realloc error in lhash",stderr); */ 268 lh->error++; 269 } else { 270 lh->b = n; 271 } 272 lh->num_alloc_nodes /= 2; 273 lh->pmax /= 2; 274 lh->p = lh->pmax - 1; 275 } else 276 lh->p--; 277 278 lh->num_nodes--; 279 280 n1 = lh->b[(int)lh->p]; 281 if (n1 == NULL) 282 lh->b[(int)lh->p] = np; 283 else { 284 while (n1->next != NULL) 285 n1 = n1->next; 286 n1->next = np; 287 } 288} 289 290static OPENSSL_LH_NODE **getrn(OPENSSL_LHASH *lh, 291 const void *data, unsigned long *rhash) 292{ 293 OPENSSL_LH_NODE **ret, *n1; 294 unsigned long hash, nn; 295 OPENSSL_LH_COMPFUNC cf; 296 297 hash = (*(lh->hash)) (data); 298 *rhash = hash; 299 300 nn = hash % lh->pmax; 301 if (nn < lh->p) 302 nn = hash % lh->num_alloc_nodes; 303 304 cf = lh->comp; 305 ret = &(lh->b[(int)nn]); 306 for (n1 = *ret; n1 != NULL; n1 = n1->next) { 307 if (n1->hash != hash) { 308 ret = &(n1->next); 309 continue; 310 } 311 if (cf(n1->data, data) == 0) 312 break; 313 ret = &(n1->next); 314 } 315 return ret; 316} 317 318/* 319 * The following hash seems to work very well on normal text strings no 320 * collisions on /usr/dict/words and it distributes on %2^n quite well, not 321 * as good as MD5, but still good. 322 */ 323unsigned long OPENSSL_LH_strhash(const char *c) 324{ 325 unsigned long ret = 0; 326 long n; 327 unsigned long v; 328 int r; 329 330 if ((c == NULL) || (*c == '\0')) 331 return ret; 332 333 n = 0x100; 334 while (*c) { 335 v = n | (*c); 336 n += 0x100; 337 r = (int)((v >> 2) ^ v) & 0x0f; 338 /* cast to uint64_t to avoid 32 bit shift of 32 bit value */ 339 ret = (ret << r) | (unsigned long)((uint64_t)ret >> (32 - r)); 340 ret &= 0xFFFFFFFFL; 341 ret ^= v * v; 342 c++; 343 } 344 return (ret >> 16) ^ ret; 345} 346 347unsigned long ossl_lh_strcasehash(const char *c) 348{ 349 unsigned long ret = 0; 350 long n; 351 unsigned long v; 352 int r; 353 354 if (c == NULL || *c == '\0') 355 return ret; 356 357 for (n = 0x100; *c != '\0'; n += 0x100) { 358 v = n | ossl_tolower(*c); 359 r = (int)((v >> 2) ^ v) & 0x0f; 360 /* cast to uint64_t to avoid 32 bit shift of 32 bit value */ 361 ret = (ret << r) | (unsigned long)((uint64_t)ret >> (32 - r)); 362 ret &= 0xFFFFFFFFL; 363 ret ^= v * v; 364 c++; 365 } 366 return (ret >> 16) ^ ret; 367} 368 369unsigned long OPENSSL_LH_num_items(const OPENSSL_LHASH *lh) 370{ 371 return lh ? lh->num_items : 0; 372} 373 374unsigned long OPENSSL_LH_get_down_load(const OPENSSL_LHASH *lh) 375{ 376 return lh->down_load; 377} 378 379void OPENSSL_LH_set_down_load(OPENSSL_LHASH *lh, unsigned long down_load) 380{ 381 lh->down_load = down_load; 382} 383 384int OPENSSL_LH_error(OPENSSL_LHASH *lh) 385{ 386 return lh->error; 387} 388