crypto/stack/stack.c

   1 /*
   2  * Copyright 1995-2018 The OpenSSL Project Authors. All Rights Reserved.
   3  *
   4  * Licensed under the OpenSSL license (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 "internal/cryptlib.h"
  12 #include "internal/numbers.h"
  13 #include <openssl/stack.h>
  14 #include <openssl/objects.h>
  15 #include <errno.h>
  16 #include <openssl/e_os2.h>      /* For ossl_inline */
  17
  18 /*
  19  * The initial number of nodes in the array.
  20  */
  21 static const int min_nodes = 4;
  22 static const int max_nodes = SIZE_MAX / sizeof(void *) < INT_MAX
  23                              ? (int)(SIZE_MAX / sizeof(void *))
  24                              : INT_MAX;
  25
  26 struct stack_st {
  27     int num;
  28     const void **data;
  29     int sorted;
  30     int num_alloc;
  31     OPENSSL_sk_compfunc comp;
  32 };
  33
  34 OPENSSL_sk_compfunc OPENSSL_sk_set_cmp_func(OPENSSL_STACK *sk, OPENSSL_sk_compfunc c)
  35 {
  36     OPENSSL_sk_compfunc old = sk->comp;
  37
  38     if (sk->comp != c)
  39         sk->sorted = 0;
  40     sk->comp = c;
  41
  42     return old;
  43 }
  44
  45 OPENSSL_STACK *OPENSSL_sk_dup(const OPENSSL_STACK *sk)
  46 {
  47     OPENSSL_STACK *ret;
  48
  49     if ((ret = OPENSSL_malloc(sizeof(*ret))) == NULL)
  50         return NULL;
  51
  52     /* direct structure assignment */
  53     *ret = *sk;
  54
  55     if (sk->num == 0) {
  56         /* postpone |ret->data| allocation */
  57         ret->data = NULL;
  58         ret->num_alloc = 0;
  59         return ret;
  60     }
  61     /* duplicate |sk->data| content */
  62     if ((ret->data = OPENSSL_malloc(sizeof(*ret->data) * sk->num_alloc)) == NULL)
  63         goto err;
  64     memcpy(ret->data, sk->data, sizeof(void *) * sk->num);
  65     return ret;
  66  err:
  67     OPENSSL_sk_free(ret);
  68     return NULL;
  69 }
  70
  71 OPENSSL_STACK *OPENSSL_sk_deep_copy(const OPENSSL_STACK *sk,
  72                              OPENSSL_sk_copyfunc copy_func,
  73                              OPENSSL_sk_freefunc free_func)
  74 {
  75     OPENSSL_STACK *ret;
  76     int i;
  77
  78     if ((ret = OPENSSL_malloc(sizeof(*ret))) == NULL)
  79         return NULL;
  80
  81     /* direct structure assignment */
  82     *ret = *sk;
  83
  84     if (sk->num == 0) {
  85         /* postpone |ret| data allocation */
  86         ret->data = NULL;
  87         ret->num_alloc = 0;
  88         return ret;
  89     }
  90
  91     ret->num_alloc = sk->num > min_nodes ? sk->num : min_nodes;
  92     ret->data = OPENSSL_zalloc(sizeof(*ret->data) * ret->num_alloc);
  93     if (ret->data == NULL) {
  94         OPENSSL_free(ret);
  95         return NULL;
  96     }
  97
  98     for (i = 0; i < ret->num; ++i) {
  99         if (sk->data[i] == NULL)
 100             continue;
 101         if ((ret->data[i] = copy_func(sk->data[i])) == NULL) {
 102             while (--i >= 0)
 103                 if (ret->data[i] != NULL)
 104                     free_func((void *)ret->data[i]);
 105             OPENSSL_sk_free(ret);
 106             return NULL;
 107         }
 108     }
 109     return ret;
 110 }
 111
 112 OPENSSL_STACK *OPENSSL_sk_new_null(void)
 113 {
 114     return OPENSSL_sk_new_reserve(NULL, 0);
 115 }
 116
 117 OPENSSL_STACK *OPENSSL_sk_new(OPENSSL_sk_compfunc c)
 118 {
 119     return OPENSSL_sk_new_reserve(c, 0);
 120 }
 121
 122 /*
 123  * Calculate the array growth based on the target size.
 124  *
 125  * The growth fraction is a rational number and is defined by a numerator
 126  * and a denominator.  According to Andrew Koenig in his paper "Why Are
 127  * Vectors Efficient?" from JOOP 11(5) 1998, this factor should be less
 128  * than the golden ratio (1.618...).
 129  *
 130  * We use 3/2 = 1.5 for simplicity of calculation and overflow checking.
 131  * Another option 8/5 = 1.6 allows for slightly faster growth, although safe
 132  * computation is more difficult.
 133  *
 134  * The limit to avoid overflow is spot on.  The modulo three correction term
 135  * ensures that the limit is the largest number than can be expanded by the
 136  * growth factor without exceeding the hard limit.
 137  *
 138  * Do not call it with |current| lower than 2, or it will infinitely loop.
 139  */
 140 static ossl_inline int compute_growth(int target, int current)
 141 {
 142     const int limit = (max_nodes / 3) * 2 + (max_nodes % 3 ? 1 : 0);
 143
 144     while (current < target) {
 145         /* Check to see if we're at the hard limit */
 146         if (current >= max_nodes)
 147             return 0;
 148
 149         /* Expand the size by a factor of 3/2 if it is within range */
 150         current = current < limit ? current + current / 2 : max_nodes;
 151     }
 152     return current;
 153 }
 154
 155 /* internal STACK storage allocation */
 156 static int sk_reserve(OPENSSL_STACK *st, int n, int exact)
 157 {
 158     const void **tmpdata;
 159     int num_alloc;
 160
 161     /* Check to see the reservation isn't exceeding the hard limit */
 162     if (n > max_nodes - st->num)
 163         return 0;
 164
 165     /* Figure out the new size */
 166     num_alloc = st->num + n;
 167     if (num_alloc < min_nodes)
 168         num_alloc = min_nodes;
 169
 170     /* If |st->data| allocation was postponed */
 171     if (st->data == NULL) {
 172         /*
 173          * At this point, |st->num_alloc| and |st->num| are 0;
 174          * so |num_alloc| value is |n| or |min_nodes| if greater than |n|.
 175          */
 176         if ((st->data = OPENSSL_zalloc(sizeof(void *) * num_alloc)) == NULL) {
 177             /* STACKerr(STACK_F_SK_RESERVE, ERR_R_MALLOC_FAILURE); */
 178             return 0;
 179         }
 180         st->num_alloc = num_alloc;
 181         return 1;
 182     }
 183
 184     if (!exact) {
 185         if (num_alloc <= st->num_alloc)
 186             return 1;
 187         num_alloc = compute_growth(num_alloc, st->num_alloc);
 188         if (num_alloc == 0)
 189             return 0;
 190     } else if (num_alloc == st->num_alloc) {
 191         return 1;
 192     }
 193
 194     tmpdata = OPENSSL_realloc((void *)st->data, sizeof(void *) * num_alloc);
 195     if (tmpdata == NULL)
 196         return 0;
 197
 198     st->data = tmpdata;
 199     st->num_alloc = num_alloc;
 200     return 1;
 201 }
 202
 203 OPENSSL_STACK *OPENSSL_sk_new_reserve(OPENSSL_sk_compfunc c, int n)
 204 {
 205     OPENSSL_STACK *st = OPENSSL_zalloc(sizeof(OPENSSL_STACK));
 206
 207     if (st == NULL)
 208         return NULL;
 209
 210     st->comp = c;
 211
 212     if (n <= 0)
 213         return st;
 214
 215     if (!sk_reserve(st, n, 1)) {
 216         OPENSSL_sk_free(st);
 217         return NULL;
 218     }
 219
 220     return st;
 221 }
 222
 223 int OPENSSL_sk_reserve(OPENSSL_STACK *st, int n)
 224 {
 225     if (st == NULL)
 226         return 0;
 227
 228     if (n < 0)
 229         return 1;
 230     return sk_reserve(st, n, 1);
 231 }
 232
 233 int OPENSSL_sk_insert(OPENSSL_STACK *st, const void *data, int loc)
 234 {
 235     if (st == NULL || st->num == max_nodes)
 236         return 0;
 237
 238     if (!sk_reserve(st, 1, 0))
 239         return 0;
 240
 241     if ((loc >= st->num) || (loc < 0)) {
 242         st->data[st->num] = data;
 243     } else {
 244         memmove(&st->data[loc + 1], &st->data[loc],
 245                 sizeof(st->data[0]) * (st->num - loc));
 246         st->data[loc] = data;
 247     }
 248     st->num++;
 249     st->sorted = 0;
 250     return st->num;
 251 }
 252
 253 static ossl_inline void *internal_delete(OPENSSL_STACK *st, int loc)
 254 {
 255     const void *ret = st->data[loc];
 256
 257     if (loc != st->num - 1)
 258          memmove(&st->data[loc], &st->data[loc + 1],
 259                  sizeof(st->data[0]) * (st->num - loc - 1));
 260     st->num--;
 261
 262     return (void *)ret;
 263 }
 264
 265 void *OPENSSL_sk_delete_ptr(OPENSSL_STACK *st, const void *p)
 266 {
 267     int i;
 268
 269     for (i = 0; i < st->num; i++)
 270         if (st->data[i] == p)
 271             return internal_delete(st, i);
 272     return NULL;
 273 }
 274
 275 void *OPENSSL_sk_delete(OPENSSL_STACK *st, int loc)
 276 {
 277     if (st == NULL || loc < 0 || loc >= st->num)
 278         return NULL;
 279
 280     return internal_delete(st, loc);
 281 }
 282
 283 static int internal_find(OPENSSL_STACK *st, const void *data,
 284                          int ret_val_options)
 285 {
 286     const void *r;
 287     int i;
 288
 289     if (st == NULL || st->num == 0)
 290         return -1;
 291
 292     if (st->comp == NULL) {
 293         for (i = 0; i < st->num; i++)
 294             if (st->data[i] == data)
 295                 return i;
 296         return -1;
 297     }
 298
 299     if (!st->sorted) {
 300         if (st->num > 1)
 301             qsort(st->data, st->num, sizeof(void *), st->comp);
 302         st->sorted = 1; /* empty or single-element stack is considered sorted */
 303     }
 304     if (data == NULL)
 305         return -1;
 306     r = OBJ_bsearch_ex_(&data, st->data, st->num, sizeof(void *), st->comp,
 307                         ret_val_options);
 308
 309     return r == NULL ? -1 : (int)((const void **)r - st->data);
 310 }
 311
 312 int OPENSSL_sk_find(OPENSSL_STACK *st, const void *data)
 313 {
 314     return internal_find(st, data, OBJ_BSEARCH_FIRST_VALUE_ON_MATCH);
 315 }
 316
 317 int OPENSSL_sk_find_ex(OPENSSL_STACK *st, const void *data)
 318 {
 319     return internal_find(st, data, OBJ_BSEARCH_VALUE_ON_NOMATCH);
 320 }
 321
 322 int OPENSSL_sk_push(OPENSSL_STACK *st, const void *data)
 323 {
 324     if (st == NULL)
 325         return -1;
 326     return OPENSSL_sk_insert(st, data, st->num);
 327 }
 328
 329 int OPENSSL_sk_unshift(OPENSSL_STACK *st, const void *data)
 330 {
 331     return OPENSSL_sk_insert(st, data, 0);
 332 }
 333
 334 void *OPENSSL_sk_shift(OPENSSL_STACK *st)
 335 {
 336     if (st == NULL || st->num == 0)
 337         return NULL;
 338     return internal_delete(st, 0);
 339 }
 340
 341 void *OPENSSL_sk_pop(OPENSSL_STACK *st)
 342 {
 343     if (st == NULL || st->num == 0)
 344         return NULL;
 345     return internal_delete(st, st->num - 1);
 346 }
 347
 348 void OPENSSL_sk_zero(OPENSSL_STACK *st)
 349 {
 350     if (st == NULL || st->num == 0)
 351         return;
 352     memset(st->data, 0, sizeof(*st->data) * st->num);
 353     st->num = 0;
 354 }
 355
 356 void OPENSSL_sk_pop_free(OPENSSL_STACK *st, OPENSSL_sk_freefunc func)
 357 {
 358     int i;
 359
 360     if (st == NULL)
 361         return;
 362     for (i = 0; i < st->num; i++)
 363         if (st->data[i] != NULL)
 364             func((char *)st->data[i]);
 365     OPENSSL_sk_free(st);
 366 }
 367
 368 void OPENSSL_sk_free(OPENSSL_STACK *st)
 369 {
 370     if (st == NULL)
 371         return;
 372     OPENSSL_free(st->data);
 373     OPENSSL_free(st);
 374 }
 375
 376 int OPENSSL_sk_num(const OPENSSL_STACK *st)
 377 {
 378     return st == NULL ? -1 : st->num;
 379 }
 380
 381 void *OPENSSL_sk_value(const OPENSSL_STACK *st, int i)
 382 {
 383     if (st == NULL || i < 0 || i >= st->num)
 384         return NULL;
 385     return (void *)st->data[i];
 386 }
 387
 388 void *OPENSSL_sk_set(OPENSSL_STACK *st, int i, const void *data)
 389 {
 390     if (st == NULL || i < 0 || i >= st->num)
 391         return NULL;
 392     st->data[i] = data;
 393     st->sorted = 0;
 394     return (void *)st->data[i];
 395 }
 396
 397 void OPENSSL_sk_sort(OPENSSL_STACK *st)
 398 {
 399     if (st != NULL && !st->sorted && st->comp != NULL) {
 400         if (st->num > 1)
 401             qsort(st->data, st->num, sizeof(void *), st->comp);
 402         st->sorted = 1; /* empty or single-element stack is considered sorted */
 403     }
 404 }
 405
 406 int OPENSSL_sk_is_sorted(const OPENSSL_STACK *st)
 407 {
 408     return st == NULL ? 1 : st->sorted;
 409 }