1/*
2 * Copyright 1995-2018 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 * CRYPTOerr(CRYPTO_F_OPENSSL_LH_NEW, 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
105void *OPENSSL_LH_insert(OPENSSL_LHASH *lh, void *data)
106{
107 unsigned long hash;
108 OPENSSL_LH_NODE *nn, **rn;
109 void *ret;
110
111 lh->error = 0;
112 if ((lh->up_load <= (lh->num_items * LH_LOAD_MULT / lh->num_nodes)) && !expand(lh))
113 return NULL; /* 'lh->error++' already done in 'expand' */
114
115 rn = getrn(lh, data, &hash);
116
117 if (*rn == NULL) {
118 if ((nn = OPENSSL_malloc(sizeof(*nn))) == NULL) {
119 lh->error++;
120 return NULL;
121 }
122 nn->data = data;
123 nn->next = NULL;
124 nn->hash = hash;
125 *rn = nn;
126 ret = NULL;
127 lh->num_insert++;
128 lh->num_items++;
129 } else { /* replace same key */
130 ret = (*rn)->data;
131 (*rn)->data = data;
132 lh->num_replace++;
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 lh->num_no_delete++;
148 return NULL;
149 } else {
150 nn = *rn;
151 *rn = nn->next;
152 ret = nn->data;
153 OPENSSL_free(nn);
154 lh->num_delete++;
155 }
156
157 lh->num_items--;
158 if ((lh->num_nodes > MIN_NODES) &&
159 (lh->down_load >= (lh->num_items * LH_LOAD_MULT / lh->num_nodes)))
160 contract(lh);
161
162 return ret;
163}
164
165void *OPENSSL_LH_retrieve(OPENSSL_LHASH *lh, const void *data)
166{
167 unsigned long hash;
168 OPENSSL_LH_NODE **rn;
169 void *ret;
170
171 tsan_store((TSAN_QUALIFIER int *)&lh->error, 0);
172
173 rn = getrn(lh, data, &hash);
174
175 if (*rn == NULL) {
176 tsan_counter(&lh->num_retrieve_miss);
177 return NULL;
178 } else {
179 ret = (*rn)->data;
180 tsan_counter(&lh->num_retrieve);
181 }
182
183 return ret;
184}
185
186static void doall_util_fn(OPENSSL_LHASH *lh, int use_arg,
187 OPENSSL_LH_DOALL_FUNC func,
188 OPENSSL_LH_DOALL_FUNCARG func_arg, void *arg)
189{
190 int i;
191 OPENSSL_LH_NODE *a, *n;
192
193 if (lh == NULL)
194 return;
195
196 /*
197 * reverse the order so we search from 'top to bottom' We were having
198 * memory leaks otherwise
199 */
200 for (i = lh->num_nodes - 1; i >= 0; i--) {
201 a = lh->b[i];
202 while (a != NULL) {
203 n = a->next;
204 if (use_arg)
205 func_arg(a->data, arg);
206 else
207 func(a->data);
208 a = n;
209 }
210 }
211}
212
213void OPENSSL_LH_doall(OPENSSL_LHASH *lh, OPENSSL_LH_DOALL_FUNC func)
214{
215 doall_util_fn(lh, 0, func, (OPENSSL_LH_DOALL_FUNCARG)0, NULL);
216}
217
218void OPENSSL_LH_doall_arg(OPENSSL_LHASH *lh, OPENSSL_LH_DOALL_FUNCARG func, void *arg)
219{
220 doall_util_fn(lh, 1, (OPENSSL_LH_DOALL_FUNC)0, func, arg);
221}
222
223static int expand(OPENSSL_LHASH *lh)
224{
225 OPENSSL_LH_NODE **n, **n1, **n2, *np;
226 unsigned int p, pmax, nni, j;
227 unsigned long hash;
228
229 nni = lh->num_alloc_nodes;
230 p = lh->p;
231 pmax = lh->pmax;
232 if (p + 1 >= pmax) {
233 j = nni * 2;
234 n = OPENSSL_realloc(lh->b, sizeof(OPENSSL_LH_NODE *) * j);
235 if (n == NULL) {
236 lh->error++;
237 return 0;
238 }
239 lh->b = n;
240 memset(n + nni, 0, sizeof(*n) * (j - nni));
241 lh->pmax = nni;
242 lh->num_alloc_nodes = j;
243 lh->num_expand_reallocs++;
244 lh->p = 0;
245 } else {
246 lh->p++;
247 }
248
249 lh->num_nodes++;
250 lh->num_expands++;
251 n1 = &(lh->b[p]);
252 n2 = &(lh->b[p + pmax]);
253 *n2 = NULL;
254
255 for (np = *n1; np != NULL;) {
256 hash = np->hash;
257 if ((hash % nni) != p) { /* move it */
258 *n1 = (*n1)->next;
259 np->next = *n2;
260 *n2 = np;
261 } else
262 n1 = &((*n1)->next);
263 np = *n1;
264 }
265
266 return 1;
267}
268
269static void contract(OPENSSL_LHASH *lh)
270{
271 OPENSSL_LH_NODE **n, *n1, *np;
272
273 np = lh->b[lh->p + lh->pmax - 1];
274 lh->b[lh->p + lh->pmax - 1] = NULL; /* 24/07-92 - eay - weird but :-( */
275 if (lh->p == 0) {
276 n = OPENSSL_realloc(lh->b,
277 (unsigned int)(sizeof(OPENSSL_LH_NODE *) * lh->pmax));
278 if (n == NULL) {
279 /* fputs("realloc error in lhash",stderr); */
280 lh->error++;
281 return;
282 }
283 lh->num_contract_reallocs++;
284 lh->num_alloc_nodes /= 2;
285 lh->pmax /= 2;
286 lh->p = lh->pmax - 1;
287 lh->b = n;
288 } else
289 lh->p--;
290
291 lh->num_nodes--;
292 lh->num_contracts++;
293
294 n1 = lh->b[(int)lh->p];
295 if (n1 == NULL)
296 lh->b[(int)lh->p] = np;
297 else {
298 while (n1->next != NULL)
299 n1 = n1->next;
300 n1->next = np;
301 }
302}
303
304static OPENSSL_LH_NODE **getrn(OPENSSL_LHASH *lh,
305 const void *data, unsigned long *rhash)
306{
307 OPENSSL_LH_NODE **ret, *n1;
308 unsigned long hash, nn;
309 OPENSSL_LH_COMPFUNC cf;
310
311 hash = (*(lh->hash)) (data);
312 tsan_counter(&lh->num_hash_calls);
313 *rhash = hash;
314
315 nn = hash % lh->pmax;
316 if (nn < lh->p)
317 nn = hash % lh->num_alloc_nodes;
318
319 cf = lh->comp;
320 ret = &(lh->b[(int)nn]);
321 for (n1 = *ret; n1 != NULL; n1 = n1->next) {
322 tsan_counter(&lh->num_hash_comps);
323 if (n1->hash != hash) {
324 ret = &(n1->next);
325 continue;
326 }
327 tsan_counter(&lh->num_comp_calls);
328 if (cf(n1->data, data) == 0)
329 break;
330 ret = &(n1->next);
331 }
332 return ret;
333}
334
335/*
336 * The following hash seems to work very well on normal text strings no
337 * collisions on /usr/dict/words and it distributes on %2^n quite well, not
338 * as good as MD5, but still good.
339 */
340unsigned long OPENSSL_LH_strhash(const char *c)
341{
342 unsigned long ret = 0;
343 long n;
344 unsigned long v;
345 int r;
346
347 if ((c == NULL) || (*c == '\0'))
348 return ret;
349
350 n = 0x100;
351 while (*c) {
352 v = n | (*c);
353 n += 0x100;
354 r = (int)((v >> 2) ^ v) & 0x0f;
355 ret = (ret << r) | (ret >> (32 - r));
356 ret &= 0xFFFFFFFFL;
357 ret ^= v * v;
358 c++;
359 }
360 return (ret >> 16) ^ ret;
361}
362
363unsigned long openssl_lh_strcasehash(const char *c)
364{
365 unsigned long ret = 0;
366 long n;
367 unsigned long v;
368 int r;
369
370 if (c == NULL || *c == '\0')
371 return ret;
372
373 for (n = 0x100; *c != '\0'; n += 0x100) {
374 v = n | ossl_tolower(*c);
375 r = (int)((v >> 2) ^ v) & 0x0f;
376 ret = (ret << r) | (ret >> (32 - r));
377 ret &= 0xFFFFFFFFL;
378 ret ^= v * v;
379 c++;
380 }
381 return (ret >> 16) ^ ret;
382}
383
384unsigned long OPENSSL_LH_num_items(const OPENSSL_LHASH *lh)
385{
386 return lh ? lh->num_items : 0;
387}
388
389unsigned long OPENSSL_LH_get_down_load(const OPENSSL_LHASH *lh)
390{
391 return lh->down_load;
392}
393
394void OPENSSL_LH_set_down_load(OPENSSL_LHASH *lh, unsigned long down_load)
395{
396 lh->down_load = down_load;
397}
398
399int OPENSSL_LH_error(OPENSSL_LHASH *lh)
400{
401 return lh->error;
402}
403