crypto/stack/stack.c

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