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