crypto/stack/stack.c

   1 /*
   2  * Copyright 1995-2021 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 "internal/cryptlib.h"
  12 #include "internal/numbers.h"
  13 #include <openssl/stack.h>
  14 #include <errno.h>
  15 #include <openssl/e_os2.h>      /* For ossl_inline */
  16
  17 /*
  18  * The initial number of nodes in the array.
  19  */
  20 static const int min_nodes = 4;
  21 static const int max_nodes = SIZE_MAX / sizeof(void *) < INT_MAX
  22                              ? (int)(SIZE_MAX / sizeof(void *))
  23                              : INT_MAX;
  24
  25 struct stack_st {
  26     int num;
  27     const void **data;
  28     int sorted;
  29     int num_alloc;
  30     OPENSSL_sk_compfunc comp;
  31 };
  32
  33 OPENSSL_sk_compfunc OPENSSL_sk_set_cmp_func(OPENSSL_STACK *sk, OPENSSL_sk_compfunc c)
  34 {
  35     OPENSSL_sk_compfunc old = sk->comp;
  36
  37     if (sk->comp != c)
  38         sk->sorted = 0;
  39     sk->comp = c;
  40
  41     return old;
  42 }
  43
  44 OPENSSL_STACK *OPENSSL_sk_dup(const OPENSSL_STACK *sk)
  45 {
  46     OPENSSL_STACK *ret;
  47
  48     if ((ret = OPENSSL_malloc(sizeof(*ret))) == NULL)
  49         goto err;
  50
  51     if (sk == NULL) {
  52         ret->num = 0;
  53         ret->sorted = 0;
  54         ret->comp = NULL;
  55     } else {
  56         /* direct structure assignment */
  57         *ret = *sk;
  58     }
  59
  60     if (sk == NULL || sk->num == 0) {
  61         /* postpone |ret->data| allocation */
  62         ret->data = NULL;
  63         ret->num_alloc = 0;
  64         return ret;
  65     }
  66
  67     /* duplicate |sk->data| content */
  68     if ((ret->data = OPENSSL_malloc(sizeof(*ret->data) * sk->num_alloc)) == NULL)
  69         goto err;
  70     memcpy(ret->data, sk->data, sizeof(void *) * sk->num);
  71     return ret;
  72
  73  err:
  74     ERR_raise(ERR_LIB_CRYPTO, ERR_R_MALLOC_FAILURE);
  75     OPENSSL_sk_free(ret);
  76     return NULL;
  77 }
  78
  79 OPENSSL_STACK *OPENSSL_sk_deep_copy(const OPENSSL_STACK *sk,
  80                              OPENSSL_sk_copyfunc copy_func,
  81                              OPENSSL_sk_freefunc free_func)
  82 {
  83     OPENSSL_STACK *ret;
  84     int i;
  85
  86     if ((ret = OPENSSL_malloc(sizeof(*ret))) == NULL)
  87         goto err;
  88
  89     if (sk == NULL) {
  90         ret->num = 0;
  91         ret->sorted = 0;
  92         ret->comp = NULL;
  93     } else {
  94         /* direct structure assignment */
  95         *ret = *sk;
  96     }
  97
  98     if (sk == NULL || sk->num == 0) {
  99         /* postpone |ret| data allocation */
 100         ret->data = NULL;
 101         ret->num_alloc = 0;
 102         return ret;
 103     }
 104
 105     ret->num_alloc = sk->num > min_nodes ? sk->num : min_nodes;
 106     ret->data = OPENSSL_zalloc(sizeof(*ret->data) * ret->num_alloc);
 107     if (ret->data == NULL)
 108         goto err;
 109
 110     for (i = 0; i < ret->num; ++i) {
 111         if (sk->data[i] == NULL)
 112             continue;
 113         if ((ret->data[i] = copy_func(sk->data[i])) == NULL) {
 114             while (--i >= 0)
 115                 if (ret->data[i] != NULL)
 116                     free_func((void *)ret->data[i]);
 117             goto err;
 118         }
 119     }
 120     return ret;
 121
 122  err:
 123     ERR_raise(ERR_LIB_CRYPTO, ERR_R_MALLOC_FAILURE);
 124     OPENSSL_sk_free(ret);
 125     return NULL;
 126 }
 127
 128 OPENSSL_STACK *OPENSSL_sk_new_null(void)
 129 {
 130     return OPENSSL_sk_new_reserve(NULL, 0);
 131 }
 132
 133 OPENSSL_STACK *OPENSSL_sk_new(OPENSSL_sk_compfunc c)
 134 {
 135     return OPENSSL_sk_new_reserve(c, 0);
 136 }
 137
 138 /*
 139  * Calculate the array growth based on the target size.
 140  *
 141  * The growth fraction is a rational number and is defined by a numerator
 142  * and a denominator.  According to Andrew Koenig in his paper "Why Are
 143  * Vectors Efficient?" from JOOP 11(5) 1998, this factor should be less
 144  * than the golden ratio (1.618...).
 145  *
 146  * We use 3/2 = 1.5 for simplicity of calculation and overflow checking.
 147  * Another option 8/5 = 1.6 allows for slightly faster growth, although safe
 148  * computation is more difficult.
 149  *
 150  * The limit to avoid overflow is spot on.  The modulo three correction term
 151  * ensures that the limit is the largest number than can be expanded by the
 152  * growth factor without exceeding the hard limit.
 153  *
 154  * Do not call it with |current| lower than 2, or it will infinitely loop.
 155  */
 156 static ossl_inline int compute_growth(int target, int current)
 157 {
 158     const int limit = (max_nodes / 3) * 2 + (max_nodes % 3 ? 1 : 0);
 159
 160     while (current < target) {
 161         /* Check to see if we're at the hard limit */
 162         if (current >= max_nodes)
 163             return 0;
 164
 165         /* Expand the size by a factor of 3/2 if it is within range */
 166         current = current < limit ? current + current / 2 : max_nodes;
 167     }
 168     return current;
 169 }
 170
 171 /* internal STACK storage allocation */
 172 static int sk_reserve(OPENSSL_STACK *st, int n, int exact)
 173 {
 174     const void **tmpdata;
 175     int num_alloc;
 176
 177     /* Check to see the reservation isn't exceeding the hard limit */
 178     if (n > max_nodes - st->num)
 179         return 0;
 180
 181     /* Figure out the new size */
 182     num_alloc = st->num + n;
 183     if (num_alloc < min_nodes)
 184         num_alloc = min_nodes;
 185
 186     /* If |st->data| allocation was postponed */
 187     if (st->data == NULL) {
 188         /*
 189          * At this point, |st->num_alloc| and |st->num| are 0;
 190          * so |num_alloc| value is |n| or |min_nodes| if greater than |n|.
 191          */
 192         if ((st->data = OPENSSL_zalloc(sizeof(void *) * num_alloc)) == NULL) {
 193             ERR_raise(ERR_LIB_CRYPTO, ERR_R_MALLOC_FAILURE);
 194             return 0;
 195         }
 196         st->num_alloc = num_alloc;
 197         return 1;
 198     }
 199
 200     if (!exact) {
 201         if (num_alloc <= st->num_alloc)
 202             return 1;
 203         num_alloc = compute_growth(num_alloc, st->num_alloc);
 204         if (num_alloc == 0)
 205             return 0;
 206     } else if (num_alloc == st->num_alloc) {
 207         return 1;
 208     }
 209
 210     tmpdata = OPENSSL_realloc((void *)st->data, sizeof(void *) * num_alloc);
 211     if (tmpdata == NULL)
 212         return 0;
 213
 214     st->data = tmpdata;
 215     st->num_alloc = num_alloc;
 216     return 1;
 217 }
 218
 219 OPENSSL_STACK *OPENSSL_sk_new_reserve(OPENSSL_sk_compfunc c, int n)
 220 {
 221     OPENSSL_STACK *st = OPENSSL_zalloc(sizeof(OPENSSL_STACK));
 222
 223     if (st == NULL)
 224         return NULL;
 225
 226     st->comp = c;
 227
 228     if (n <= 0)
 229         return st;
 230
 231     if (!sk_reserve(st, n, 1)) {
 232         OPENSSL_sk_free(st);
 233         return NULL;
 234     }
 235
 236     return st;
 237 }
 238
 239 int OPENSSL_sk_reserve(OPENSSL_STACK *st, int n)
 240 {
 241     if (st == NULL)
 242         return 0;
 243
 244     if (n < 0)
 245         return 1;
 246     return sk_reserve(st, n, 1);
 247 }
 248
 249 int OPENSSL_sk_insert(OPENSSL_STACK *st, const void *data, int loc)
 250 {
 251     if (st == NULL || st->num == max_nodes)
 252         return 0;
 253
 254     if (!sk_reserve(st, 1, 0))
 255         return 0;
 256
 257     if ((loc >= st->num) || (loc < 0)) {
 258         st->data[st->num] = data;
 259     } else {
 260         memmove(&st->data[loc + 1], &st->data[loc],
 261                 sizeof(st->data[0]) * (st->num - loc));
 262         st->data[loc] = data;
 263     }
 264     st->num++;
 265     st->sorted = 0;
 266     return st->num;
 267 }
 268
 269 static ossl_inline void *internal_delete(OPENSSL_STACK *st, int loc)
 270 {
 271     const void *ret = st->data[loc];
 272
 273     if (loc != st->num - 1)
 274          memmove(&st->data[loc], &st->data[loc + 1],
 275                  sizeof(st->data[0]) * (st->num - loc - 1));
 276     st->num--;
 277
 278     return (void *)ret;
 279 }
 280
 281 void *OPENSSL_sk_delete_ptr(OPENSSL_STACK *st, const void *p)
 282 {
 283     int i;
 284
 285     for (i = 0; i < st->num; i++)
 286         if (st->data[i] == p)
 287             return internal_delete(st, i);
 288     return NULL;
 289 }
 290
 291 void *OPENSSL_sk_delete(OPENSSL_STACK *st, int loc)
 292 {
 293     if (st == NULL || loc < 0 || loc >= st->num)
 294         return NULL;
 295
 296     return internal_delete(st, loc);
 297 }
 298
 299 static int internal_find(OPENSSL_STACK *st, const void *data,
 300                          int ret_val_options)
 301 {
 302     const void *r;
 303     int i;
 304
 305     if (st == NULL || st->num == 0)
 306         return -1;
 307
 308     if (st->comp == NULL) {
 309         for (i = 0; i < st->num; i++)
 310             if (st->data[i] == data)
 311                 return i;
 312         return -1;
 313     }
 314
 315     if (!st->sorted) {
 316         if (st->num > 1)
 317             qsort(st->data, st->num, sizeof(void *), st->comp);
 318         st->sorted = 1; /* empty or single-element stack is considered sorted */
 319     }
 320     if (data == NULL)
 321         return -1;
 322     r = ossl_bsearch(&data, st->data, st->num, sizeof(void *), st->comp,
 323                      ret_val_options);
 324
 325     return r == NULL ? -1 : (int)((const void **)r - st->data);
 326 }
 327
 328 int OPENSSL_sk_find(OPENSSL_STACK *st, const void *data)
 329 {
 330     return internal_find(st, data, OSSL_BSEARCH_FIRST_VALUE_ON_MATCH);
 331 }
 332
 333 int OPENSSL_sk_find_ex(OPENSSL_STACK *st, const void *data)
 334 {
 335     return internal_find(st, data, OSSL_BSEARCH_VALUE_ON_NOMATCH);
 336 }
 337
 338 int OPENSSL_sk_push(OPENSSL_STACK *st, const void *data)
 339 {
 340     if (st == NULL)
 341         return -1;
 342     return OPENSSL_sk_insert(st, data, st->num);
 343 }
 344
 345 int OPENSSL_sk_unshift(OPENSSL_STACK *st, const void *data)
 346 {
 347     return OPENSSL_sk_insert(st, data, 0);
 348 }
 349
 350 void *OPENSSL_sk_shift(OPENSSL_STACK *st)
 351 {
 352     if (st == NULL || st->num == 0)
 353         return NULL;
 354     return internal_delete(st, 0);
 355 }
 356
 357 void *OPENSSL_sk_pop(OPENSSL_STACK *st)
 358 {
 359     if (st == NULL || st->num == 0)
 360         return NULL;
 361     return internal_delete(st, st->num - 1);
 362 }
 363
 364 void OPENSSL_sk_zero(OPENSSL_STACK *st)
 365 {
 366     if (st == NULL || st->num == 0)
 367         return;
 368     memset(st->data, 0, sizeof(*st->data) * st->num);
 369     st->num = 0;
 370 }
 371
 372 void OPENSSL_sk_pop_free(OPENSSL_STACK *st, OPENSSL_sk_freefunc func)
 373 {
 374     int i;
 375
 376     if (st == NULL)
 377         return;
 378     for (i = 0; i < st->num; i++)
 379         if (st->data[i] != NULL)
 380             func((char *)st->data[i]);
 381     OPENSSL_sk_free(st);
 382 }
 383
 384 void OPENSSL_sk_free(OPENSSL_STACK *st)
 385 {
 386     if (st == NULL)
 387         return;
 388     OPENSSL_free(st->data);
 389     OPENSSL_free(st);
 390 }
 391
 392 int OPENSSL_sk_num(const OPENSSL_STACK *st)
 393 {
 394     return st == NULL ? -1 : st->num;
 395 }
 396
 397 void *OPENSSL_sk_value(const OPENSSL_STACK *st, int i)
 398 {
 399     if (st == NULL || i < 0 || i >= st->num)
 400         return NULL;
 401     return (void *)st->data[i];
 402 }
 403
 404 void *OPENSSL_sk_set(OPENSSL_STACK *st, int i, const void *data)
 405 {
 406     if (st == NULL || i < 0 || i >= st->num)
 407         return NULL;
 408     st->data[i] = data;
 409     st->sorted = 0;
 410     return (void *)st->data[i];
 411 }
 412
 413 void OPENSSL_sk_sort(OPENSSL_STACK *st)
 414 {
 415     if (st != NULL && !st->sorted && st->comp != NULL) {
 416         if (st->num > 1)
 417             qsort(st->data, st->num, sizeof(void *), st->comp);
 418         st->sorted = 1; /* empty or single-element stack is considered sorted */
 419     }
 420 }
 421
 422 int OPENSSL_sk_is_sorted(const OPENSSL_STACK *st)
 423 {
 424     return st == NULL ? 1 : st->sorted;
 425 }