crypto/mem_sec.c

   1 /*
   2  * Copyright 2015-2018 The OpenSSL Project Authors. All Rights Reserved.
   3  * Copyright 2004-2014, Akamai Technologies. All Rights Reserved.
   4  *
   5  * Licensed under the Apache License 2.0 (the "License").  You may not use
   6  * this file except in compliance with the License.  You can obtain a copy
   7  * in the file LICENSE in the source distribution or at
   8  * https://www.openssl.org/source/license.html
   9  */
  10
  11 /*
  12  * This file is in two halves. The first half implements the public API
  13  * to be used by external consumers, and to be used by OpenSSL to store
  14  * data in a "secure arena." The second half implements the secure arena.
  15  * For details on that implementation, see below (look for uppercase
  16  * "SECURE HEAP IMPLEMENTATION").
  17  */
  18 #include "e_os.h"
  19 #include <openssl/crypto.h>
  20
  21 #include <string.h>
  22
  23 /* e_os.h defines OPENSSL_SECURE_MEMORY if secure memory can be implemented */
  24 #ifdef OPENSSL_SECURE_MEMORY
  25 # include <stdlib.h>
  26 # include <assert.h>
  27 # include <unistd.h>
  28 # include <sys/types.h>
  29 # include <sys/mman.h>
  30 # if defined(OPENSSL_SYS_LINUX)
  31 #  include <sys/syscall.h>
  32 #  if defined(SYS_mlock2)
  33 #   include <linux/mman.h>
  34 #   include <errno.h>
  35 #  endif
  36 #  include <sys/param.h>
  37 # endif
  38 # include <sys/stat.h>
  39 # include <fcntl.h>
  40 #endif
  41
  42 #define CLEAR(p, s) OPENSSL_cleanse(p, s)
  43 #ifndef PAGE_SIZE
  44 # define PAGE_SIZE    4096
  45 #endif
  46 #if !defined(MAP_ANON) && defined(MAP_ANONYMOUS)
  47 # define MAP_ANON MAP_ANONYMOUS
  48 #endif
  49
  50 #ifdef OPENSSL_SECURE_MEMORY
  51 static size_t secure_mem_used;
  52
  53 static int secure_mem_initialized;
  54
  55 static CRYPTO_RWLOCK *sec_malloc_lock = NULL;
  56
  57 /*
  58  * These are the functions that must be implemented by a secure heap (sh).
  59  */
  60 static int sh_init(size_t size, int minsize);
  61 static void *sh_malloc(size_t size);
  62 static void sh_free(void *ptr);
  63 static void sh_done(void);
  64 static size_t sh_actual_size(char *ptr);
  65 static int sh_allocated(const char *ptr);
  66 #endif
  67
  68 int CRYPTO_secure_malloc_init(size_t size, int minsize)
  69 {
  70 #ifdef OPENSSL_SECURE_MEMORY
  71     int ret = 0;
  72
  73     if (!secure_mem_initialized) {
  74         sec_malloc_lock = CRYPTO_THREAD_lock_new();
  75         if (sec_malloc_lock == NULL)
  76             return 0;
  77         if ((ret = sh_init(size, minsize)) != 0) {
  78             secure_mem_initialized = 1;
  79         } else {
  80             CRYPTO_THREAD_lock_free(sec_malloc_lock);
  81             sec_malloc_lock = NULL;
  82         }
  83     }
  84
  85     return ret;
  86 #else
  87     return 0;
  88 #endif /* OPENSSL_SECURE_MEMORY */
  89 }
  90
  91 int CRYPTO_secure_malloc_done(void)
  92 {
  93 #ifdef OPENSSL_SECURE_MEMORY
  94     if (secure_mem_used == 0) {
  95         sh_done();
  96         secure_mem_initialized = 0;
  97         CRYPTO_THREAD_lock_free(sec_malloc_lock);
  98         sec_malloc_lock = NULL;
  99         return 1;
 100     }
 101 #endif /* OPENSSL_SECURE_MEMORY */
 102     return 0;
 103 }
 104
 105 int CRYPTO_secure_malloc_initialized(void)
 106 {
 107 #ifdef OPENSSL_SECURE_MEMORY
 108     return secure_mem_initialized;
 109 #else
 110     return 0;
 111 #endif /* OPENSSL_SECURE_MEMORY */
 112 }
 113
 114 void *CRYPTO_secure_malloc(size_t num, const char *file, int line)
 115 {
 116 #ifdef OPENSSL_SECURE_MEMORY
 117     void *ret;
 118     size_t actual_size;
 119
 120     if (!secure_mem_initialized) {
 121         return CRYPTO_malloc(num, file, line);
 122     }
 123     CRYPTO_THREAD_write_lock(sec_malloc_lock);
 124     ret = sh_malloc(num);
 125     actual_size = ret ? sh_actual_size(ret) : 0;
 126     secure_mem_used += actual_size;
 127     CRYPTO_THREAD_unlock(sec_malloc_lock);
 128     return ret;
 129 #else
 130     return CRYPTO_malloc(num, file, line);
 131 #endif /* OPENSSL_SECURE_MEMORY */
 132 }
 133
 134 void *CRYPTO_secure_zalloc(size_t num, const char *file, int line)
 135 {
 136 #ifdef OPENSSL_SECURE_MEMORY
 137     if (secure_mem_initialized)
 138         /* CRYPTO_secure_malloc() zeroes allocations when it is implemented */
 139         return CRYPTO_secure_malloc(num, file, line);
 140 #endif
 141     return CRYPTO_zalloc(num, file, line);
 142 }
 143
 144 void CRYPTO_secure_free(void *ptr, const char *file, int line)
 145 {
 146 #ifdef OPENSSL_SECURE_MEMORY
 147     size_t actual_size;
 148
 149     if (ptr == NULL)
 150         return;
 151     if (!CRYPTO_secure_allocated(ptr)) {
 152         CRYPTO_free(ptr, file, line);
 153         return;
 154     }
 155     CRYPTO_THREAD_write_lock(sec_malloc_lock);
 156     actual_size = sh_actual_size(ptr);
 157     CLEAR(ptr, actual_size);
 158     secure_mem_used -= actual_size;
 159     sh_free(ptr);
 160     CRYPTO_THREAD_unlock(sec_malloc_lock);
 161 #else
 162     CRYPTO_free(ptr, file, line);
 163 #endif /* OPENSSL_SECURE_MEMORY */
 164 }
 165
 166 void CRYPTO_secure_clear_free(void *ptr, size_t num,
 167                               const char *file, int line)
 168 {
 169 #ifdef OPENSSL_SECURE_MEMORY
 170     size_t actual_size;
 171
 172     if (ptr == NULL)
 173         return;
 174     if (!CRYPTO_secure_allocated(ptr)) {
 175         OPENSSL_cleanse(ptr, num);
 176         CRYPTO_free(ptr, file, line);
 177         return;
 178     }
 179     CRYPTO_THREAD_write_lock(sec_malloc_lock);
 180     actual_size = sh_actual_size(ptr);
 181     CLEAR(ptr, actual_size);
 182     secure_mem_used -= actual_size;
 183     sh_free(ptr);
 184     CRYPTO_THREAD_unlock(sec_malloc_lock);
 185 #else
 186     if (ptr == NULL)
 187         return;
 188     OPENSSL_cleanse(ptr, num);
 189     CRYPTO_free(ptr, file, line);
 190 #endif /* OPENSSL_SECURE_MEMORY */
 191 }
 192
 193 int CRYPTO_secure_allocated(const void *ptr)
 194 {
 195 #ifdef OPENSSL_SECURE_MEMORY
 196     int ret;
 197
 198     if (!secure_mem_initialized)
 199         return 0;
 200     CRYPTO_THREAD_write_lock(sec_malloc_lock);
 201     ret = sh_allocated(ptr);
 202     CRYPTO_THREAD_unlock(sec_malloc_lock);
 203     return ret;
 204 #else
 205     return 0;
 206 #endif /* OPENSSL_SECURE_MEMORY */
 207 }
 208
 209 size_t CRYPTO_secure_used(void)
 210 {
 211 #ifdef OPENSSL_SECURE_MEMORY
 212     return secure_mem_used;
 213 #else
 214     return 0;
 215 #endif /* OPENSSL_SECURE_MEMORY */
 216 }
 217
 218 size_t CRYPTO_secure_actual_size(void *ptr)
 219 {
 220 #ifdef OPENSSL_SECURE_MEMORY
 221     size_t actual_size;
 222
 223     CRYPTO_THREAD_write_lock(sec_malloc_lock);
 224     actual_size = sh_actual_size(ptr);
 225     CRYPTO_THREAD_unlock(sec_malloc_lock);
 226     return actual_size;
 227 #else
 228     return 0;
 229 #endif
 230 }
 231 /* END OF PAGE ...
 232
 233    ... START OF PAGE */
 234
 235 /*
 236  * SECURE HEAP IMPLEMENTATION
 237  */
 238 #ifdef OPENSSL_SECURE_MEMORY
 239
 240
 241 /*
 242  * The implementation provided here uses a fixed-sized mmap() heap,
 243  * which is locked into memory, not written to core files, and protected
 244  * on either side by an unmapped page, which will catch pointer overruns
 245  * (or underruns) and an attempt to read data out of the secure heap.
 246  * Free'd memory is zero'd or otherwise cleansed.
 247  *
 248  * This is a pretty standard buddy allocator.  We keep areas in a multiple
 249  * of "sh.minsize" units.  The freelist and bitmaps are kept separately,
 250  * so all (and only) data is kept in the mmap'd heap.
 251  *
 252  * This code assumes eight-bit bytes.  The numbers 3 and 7 are all over the
 253  * place.
 254  */
 255
 256 #define ONE ((size_t)1)
 257
 258 # define TESTBIT(t, b)  (t[(b) >> 3] &  (ONE << ((b) & 7)))
 259 # define SETBIT(t, b)   (t[(b) >> 3] |= (ONE << ((b) & 7)))
 260 # define CLEARBIT(t, b) (t[(b) >> 3] &= (0xFF & ~(ONE << ((b) & 7))))
 261
 262 #define WITHIN_ARENA(p) \
 263     ((char*)(p) >= sh.arena && (char*)(p) < &sh.arena[sh.arena_size])
 264 #define WITHIN_FREELIST(p) \
 265     ((char*)(p) >= (char*)sh.freelist && (char*)(p) < (char*)&sh.freelist[sh.freelist_size])
 266
 267
 268 typedef struct sh_list_st
 269 {
 270     struct sh_list_st *next;
 271     struct sh_list_st **p_next;
 272 } SH_LIST;
 273
 274 typedef struct sh_st
 275 {
 276     char* map_result;
 277     size_t map_size;
 278     char *arena;
 279     size_t arena_size;
 280     char **freelist;
 281     ossl_ssize_t freelist_size;
 282     size_t minsize;
 283     unsigned char *bittable;
 284     unsigned char *bitmalloc;
 285     size_t bittable_size; /* size in bits */
 286 } SH;
 287
 288 static SH sh;
 289
 290 static size_t sh_getlist(char *ptr)
 291 {
 292     ossl_ssize_t list = sh.freelist_size - 1;
 293     size_t bit = (sh.arena_size + ptr - sh.arena) / sh.minsize;
 294
 295     for (; bit; bit >>= 1, list--) {
 296         if (TESTBIT(sh.bittable, bit))
 297             break;
 298         OPENSSL_assert((bit & 1) == 0);
 299     }
 300
 301     return list;
 302 }
 303
 304
 305 static int sh_testbit(char *ptr, int list, unsigned char *table)
 306 {
 307     size_t bit;
 308
 309     OPENSSL_assert(list >= 0 && list < sh.freelist_size);
 310     OPENSSL_assert(((ptr - sh.arena) & ((sh.arena_size >> list) - 1)) == 0);
 311     bit = (ONE << list) + ((ptr - sh.arena) / (sh.arena_size >> list));
 312     OPENSSL_assert(bit > 0 && bit < sh.bittable_size);
 313     return TESTBIT(table, bit);
 314 }
 315
 316 static void sh_clearbit(char *ptr, int list, unsigned char *table)
 317 {
 318     size_t bit;
 319
 320     OPENSSL_assert(list >= 0 && list < sh.freelist_size);
 321     OPENSSL_assert(((ptr - sh.arena) & ((sh.arena_size >> list) - 1)) == 0);
 322     bit = (ONE << list) + ((ptr - sh.arena) / (sh.arena_size >> list));
 323     OPENSSL_assert(bit > 0 && bit < sh.bittable_size);
 324     OPENSSL_assert(TESTBIT(table, bit));
 325     CLEARBIT(table, bit);
 326 }
 327
 328 static void sh_setbit(char *ptr, int list, unsigned char *table)
 329 {
 330     size_t bit;
 331
 332     OPENSSL_assert(list >= 0 && list < sh.freelist_size);
 333     OPENSSL_assert(((ptr - sh.arena) & ((sh.arena_size >> list) - 1)) == 0);
 334     bit = (ONE << list) + ((ptr - sh.arena) / (sh.arena_size >> list));
 335     OPENSSL_assert(bit > 0 && bit < sh.bittable_size);
 336     OPENSSL_assert(!TESTBIT(table, bit));
 337     SETBIT(table, bit);
 338 }
 339
 340 static void sh_add_to_list(char **list, char *ptr)
 341 {
 342     SH_LIST *temp;
 343
 344     OPENSSL_assert(WITHIN_FREELIST(list));
 345     OPENSSL_assert(WITHIN_ARENA(ptr));
 346
 347     temp = (SH_LIST *)ptr;
 348     temp->next = *(SH_LIST **)list;
 349     OPENSSL_assert(temp->next == NULL || WITHIN_ARENA(temp->next));
 350     temp->p_next = (SH_LIST **)list;
 351
 352     if (temp->next != NULL) {
 353         OPENSSL_assert((char **)temp->next->p_next == list);
 354         temp->next->p_next = &(temp->next);
 355     }
 356
 357     *list = ptr;
 358 }
 359
 360 static void sh_remove_from_list(char *ptr)
 361 {
 362     SH_LIST *temp, *temp2;
 363
 364     temp = (SH_LIST *)ptr;
 365     if (temp->next != NULL)
 366         temp->next->p_next = temp->p_next;
 367     *temp->p_next = temp->next;
 368     if (temp->next == NULL)
 369         return;
 370
 371     temp2 = temp->next;
 372     OPENSSL_assert(WITHIN_FREELIST(temp2->p_next) || WITHIN_ARENA(temp2->p_next));
 373 }
 374
 375
 376 static int sh_init(size_t size, int minsize)
 377 {
 378     int ret;
 379     size_t i;
 380     size_t pgsize;
 381     size_t aligned;
 382
 383     memset(&sh, 0, sizeof(sh));
 384
 385     /* make sure size and minsize are powers of 2 */
 386     OPENSSL_assert(size > 0);
 387     OPENSSL_assert((size & (size - 1)) == 0);
 388     OPENSSL_assert(minsize > 0);
 389     OPENSSL_assert((minsize & (minsize - 1)) == 0);
 390     if (size <= 0 || (size & (size - 1)) != 0)
 391         goto err;
 392     if (minsize <= 0 || (minsize & (minsize - 1)) != 0)
 393         goto err;
 394
 395     while (minsize < (int)sizeof(SH_LIST))
 396         minsize *= 2;
 397
 398     sh.arena_size = size;
 399     sh.minsize = minsize;
 400     sh.bittable_size = (sh.arena_size / sh.minsize) * 2;
 401
 402     /* Prevent allocations of size 0 later on */
 403     if (sh.bittable_size >> 3 == 0)
 404         goto err;
 405
 406     sh.freelist_size = -1;
 407     for (i = sh.bittable_size; i; i >>= 1)
 408         sh.freelist_size++;
 409
 410     sh.freelist = OPENSSL_zalloc(sh.freelist_size * sizeof(char *));
 411     OPENSSL_assert(sh.freelist != NULL);
 412     if (sh.freelist == NULL)
 413         goto err;
 414
 415     sh.bittable = OPENSSL_zalloc(sh.bittable_size >> 3);
 416     OPENSSL_assert(sh.bittable != NULL);
 417     if (sh.bittable == NULL)
 418         goto err;
 419
 420     sh.bitmalloc = OPENSSL_zalloc(sh.bittable_size >> 3);
 421     OPENSSL_assert(sh.bitmalloc != NULL);
 422     if (sh.bitmalloc == NULL)
 423         goto err;
 424
 425     /* Allocate space for heap, and two extra pages as guards */
 426 #if defined(_SC_PAGE_SIZE) || defined (_SC_PAGESIZE)
 427     {
 428 # if defined(_SC_PAGE_SIZE)
 429         long tmppgsize = sysconf(_SC_PAGE_SIZE);
 430 # else
 431         long tmppgsize = sysconf(_SC_PAGESIZE);
 432 # endif
 433         if (tmppgsize < 1)
 434             pgsize = PAGE_SIZE;
 435         else
 436             pgsize = (size_t)tmppgsize;
 437     }
 438 #else
 439     pgsize = PAGE_SIZE;
 440 #endif
 441     sh.map_size = pgsize + sh.arena_size + pgsize;
 442     if (1) {
 443 #ifdef MAP_ANON
 444         sh.map_result = mmap(NULL, sh.map_size,
 445                              PROT_READ|PROT_WRITE, MAP_ANON|MAP_PRIVATE, -1, 0);
 446     } else {
 447 #endif
 448         int fd;
 449
 450         sh.map_result = MAP_FAILED;
 451         if ((fd = open("/dev/zero", O_RDWR)) >= 0) {
 452             sh.map_result = mmap(NULL, sh.map_size,
 453                                  PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
 454             close(fd);
 455         }
 456     }
 457     if (sh.map_result == MAP_FAILED)
 458         goto err;
 459     sh.arena = (char *)(sh.map_result + pgsize);
 460     sh_setbit(sh.arena, 0, sh.bittable);
 461     sh_add_to_list(&sh.freelist[0], sh.arena);
 462
 463     /* Now try to add guard pages and lock into memory. */
 464     ret = 1;
 465
 466     /* Starting guard is already aligned from mmap. */
 467     if (mprotect(sh.map_result, pgsize, PROT_NONE) < 0)
 468         ret = 2;
 469
 470     /* Ending guard page - need to round up to page boundary */
 471     aligned = (pgsize + sh.arena_size + (pgsize - 1)) & ~(pgsize - 1);
 472     if (mprotect(sh.map_result + aligned, pgsize, PROT_NONE) < 0)
 473         ret = 2;
 474
 475 #if defined(OPENSSL_SYS_LINUX) && defined(MLOCK_ONFAULT) && defined(SYS_mlock2)
 476     if (syscall(SYS_mlock2, sh.arena, sh.arena_size, MLOCK_ONFAULT) < 0) {
 477         if (errno == ENOSYS) {
 478             if (mlock(sh.arena, sh.arena_size) < 0)
 479                 ret = 2;
 480         } else {
 481             ret = 2;
 482         }
 483     }
 484 #else
 485     if (mlock(sh.arena, sh.arena_size) < 0)
 486         ret = 2;
 487 #endif
 488 #ifdef MADV_DONTDUMP
 489     if (madvise(sh.arena, sh.arena_size, MADV_DONTDUMP) < 0)
 490         ret = 2;
 491 #endif
 492
 493     return ret;
 494
 495  err:
 496     sh_done();
 497     return 0;
 498 }
 499
 500 static void sh_done(void)
 501 {
 502     OPENSSL_free(sh.freelist);
 503     OPENSSL_free(sh.bittable);
 504     OPENSSL_free(sh.bitmalloc);
 505     if (sh.map_result != NULL && sh.map_size)
 506         munmap(sh.map_result, sh.map_size);
 507     memset(&sh, 0, sizeof(sh));
 508 }
 509
 510 static int sh_allocated(const char *ptr)
 511 {
 512     return WITHIN_ARENA(ptr) ? 1 : 0;
 513 }
 514
 515 static char *sh_find_my_buddy(char *ptr, int list)
 516 {
 517     size_t bit;
 518     char *chunk = NULL;
 519
 520     bit = (ONE << list) + (ptr - sh.arena) / (sh.arena_size >> list);
 521     bit ^= 1;
 522
 523     if (TESTBIT(sh.bittable, bit) && !TESTBIT(sh.bitmalloc, bit))
 524         chunk = sh.arena + ((bit & ((ONE << list) - 1)) * (sh.arena_size >> list));
 525
 526     return chunk;
 527 }
 528
 529 static void *sh_malloc(size_t size)
 530 {
 531     ossl_ssize_t list, slist;
 532     size_t i;
 533     char *chunk;
 534
 535     if (size > sh.arena_size)
 536         return NULL;
 537
 538     list = sh.freelist_size - 1;
 539     for (i = sh.minsize; i < size; i <<= 1)
 540         list--;
 541     if (list < 0)
 542         return NULL;
 543
 544     /* try to find a larger entry to split */
 545     for (slist = list; slist >= 0; slist--)
 546         if (sh.freelist[slist] != NULL)
 547             break;
 548     if (slist < 0)
 549         return NULL;
 550
 551     /* split larger entry */
 552     while (slist != list) {
 553         char *temp = sh.freelist[slist];
 554
 555         /* remove from bigger list */
 556         OPENSSL_assert(!sh_testbit(temp, slist, sh.bitmalloc));
 557         sh_clearbit(temp, slist, sh.bittable);
 558         sh_remove_from_list(temp);
 559         OPENSSL_assert(temp != sh.freelist[slist]);
 560
 561         /* done with bigger list */
 562         slist++;
 563
 564         /* add to smaller list */
 565         OPENSSL_assert(!sh_testbit(temp, slist, sh.bitmalloc));
 566         sh_setbit(temp, slist, sh.bittable);
 567         sh_add_to_list(&sh.freelist[slist], temp);
 568         OPENSSL_assert(sh.freelist[slist] == temp);
 569
 570         /* split in 2 */
 571         temp += sh.arena_size >> slist;
 572         OPENSSL_assert(!sh_testbit(temp, slist, sh.bitmalloc));
 573         sh_setbit(temp, slist, sh.bittable);
 574         sh_add_to_list(&sh.freelist[slist], temp);
 575         OPENSSL_assert(sh.freelist[slist] == temp);
 576
 577         OPENSSL_assert(temp-(sh.arena_size >> slist) == sh_find_my_buddy(temp, slist));
 578     }
 579
 580     /* peel off memory to hand back */
 581     chunk = sh.freelist[list];
 582     OPENSSL_assert(sh_testbit(chunk, list, sh.bittable));
 583     sh_setbit(chunk, list, sh.bitmalloc);
 584     sh_remove_from_list(chunk);
 585
 586     OPENSSL_assert(WITHIN_ARENA(chunk));
 587
 588     /* zero the free list header as a precaution against information leakage */
 589     memset(chunk, 0, sizeof(SH_LIST));
 590
 591     return chunk;
 592 }
 593
 594 static void sh_free(void *ptr)
 595 {
 596     size_t list;
 597     void *buddy;
 598
 599     if (ptr == NULL)
 600         return;
 601     OPENSSL_assert(WITHIN_ARENA(ptr));
 602     if (!WITHIN_ARENA(ptr))
 603         return;
 604
 605     list = sh_getlist(ptr);
 606     OPENSSL_assert(sh_testbit(ptr, list, sh.bittable));
 607     sh_clearbit(ptr, list, sh.bitmalloc);
 608     sh_add_to_list(&sh.freelist[list], ptr);
 609
 610     /* Try to coalesce two adjacent free areas. */
 611     while ((buddy = sh_find_my_buddy(ptr, list)) != NULL) {
 612         OPENSSL_assert(ptr == sh_find_my_buddy(buddy, list));
 613         OPENSSL_assert(ptr != NULL);
 614         OPENSSL_assert(!sh_testbit(ptr, list, sh.bitmalloc));
 615         sh_clearbit(ptr, list, sh.bittable);
 616         sh_remove_from_list(ptr);
 617         OPENSSL_assert(!sh_testbit(ptr, list, sh.bitmalloc));
 618         sh_clearbit(buddy, list, sh.bittable);
 619         sh_remove_from_list(buddy);
 620
 621         list--;
 622
 623         /* Zero the higher addressed block's free list pointers */
 624         memset(ptr > buddy ? ptr : buddy, 0, sizeof(SH_LIST));
 625         if (ptr > buddy)
 626             ptr = buddy;
 627
 628         OPENSSL_assert(!sh_testbit(ptr, list, sh.bitmalloc));
 629         sh_setbit(ptr, list, sh.bittable);
 630         sh_add_to_list(&sh.freelist[list], ptr);
 631         OPENSSL_assert(sh.freelist[list] == ptr);
 632     }
 633 }
 634
 635 static size_t sh_actual_size(char *ptr)
 636 {
 637     int list;
 638
 639     OPENSSL_assert(WITHIN_ARENA(ptr));
 640     if (!WITHIN_ARENA(ptr))
 641         return 0;
 642     list = sh_getlist(ptr);
 643     OPENSSL_assert(sh_testbit(ptr, list, sh.bittable));
 644     return sh.arena_size / (ONE << list);
 645 }
 646 #endif /* OPENSSL_SECURE_MEMORY */