1 /*
2 * Copyright 2015-2023 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 #ifndef OPENSSL_NO_SECURE_MEMORY
24 # if defined(_WIN32)
25 # include <windows.h>
26 # if defined(WINAPI_FAMILY_PARTITION)
27 # if !WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_DESKTOP | WINAPI_PARTITION_SYSTEM)
28 /*
29 * While VirtualLock is available under the app partition (e.g. UWP),
30 * the headers do not define the API. Define it ourselves instead.
31 */
32 WINBASEAPI
33 BOOL
34 WINAPI
35 VirtualLock(
36 _In_ LPVOID lpAddress,
37 _In_ SIZE_T dwSize
38 );
39 # endif
40 # endif
41 # endif
42 # include <stdlib.h>
43 # include <assert.h>
44 # if defined(OPENSSL_SYS_UNIX)
45 # include <unistd.h>
46 # endif
47 # include <sys/types.h>
48 # if defined(OPENSSL_SYS_UNIX)
49 # include <sys/mman.h>
50 # if defined(__FreeBSD__)
51 # define MADV_DONTDUMP MADV_NOCORE
52 # endif
53 # if !defined(MAP_CONCEAL)
54 # define MAP_CONCEAL 0
55 # endif
56 # endif
57 # if defined(OPENSSL_SYS_LINUX)
58 # include <sys/syscall.h>
59 # if defined(SYS_mlock2)
60 # include <linux/mman.h>
61 # include <errno.h>
62 # endif
63 # include <sys/param.h>
64 # endif
65 # include <sys/stat.h>
66 # include <fcntl.h>
67 #endif
68
69 #define CLEAR(p, s) OPENSSL_cleanse(p, s)
70 #ifndef PAGE_SIZE
71 # define PAGE_SIZE 4096
72 #endif
73 #if !defined(MAP_ANON) && defined(MAP_ANONYMOUS)
74 # define MAP_ANON MAP_ANONYMOUS
75 #endif
76
77 #ifndef OPENSSL_NO_SECURE_MEMORY
78 static size_t secure_mem_used;
79
80 static int secure_mem_initialized;
81
82 static CRYPTO_RWLOCK *sec_malloc_lock = NULL;
83
84 /*
85 * These are the functions that must be implemented by a secure heap (sh).
86 */
87 static int sh_init(size_t size, size_t minsize);
88 static void *sh_malloc(size_t size);
89 static void sh_free(void *ptr);
90 static void sh_done(void);
91 static size_t sh_actual_size(char *ptr);
92 static int sh_allocated(const char *ptr);
93 #endif
94
CRYPTO_secure_malloc_init(size_t size,size_t minsize)95 int CRYPTO_secure_malloc_init(size_t size, size_t minsize)
96 {
97 #ifndef OPENSSL_NO_SECURE_MEMORY
98 int ret = 0;
99
100 if (!secure_mem_initialized) {
101 sec_malloc_lock = CRYPTO_THREAD_lock_new();
102 if (sec_malloc_lock == NULL)
103 return 0;
104 if ((ret = sh_init(size, minsize)) != 0) {
105 secure_mem_initialized = 1;
106 } else {
107 CRYPTO_THREAD_lock_free(sec_malloc_lock);
108 sec_malloc_lock = NULL;
109 }
110 }
111
112 return ret;
113 #else
114 return 0;
115 #endif /* OPENSSL_NO_SECURE_MEMORY */
116 }
117
CRYPTO_secure_malloc_done(void)118 int CRYPTO_secure_malloc_done(void)
119 {
120 #ifndef OPENSSL_NO_SECURE_MEMORY
121 if (secure_mem_used == 0) {
122 sh_done();
123 secure_mem_initialized = 0;
124 CRYPTO_THREAD_lock_free(sec_malloc_lock);
125 sec_malloc_lock = NULL;
126 return 1;
127 }
128 #endif /* OPENSSL_NO_SECURE_MEMORY */
129 return 0;
130 }
131
CRYPTO_secure_malloc_initialized(void)132 int CRYPTO_secure_malloc_initialized(void)
133 {
134 #ifndef OPENSSL_NO_SECURE_MEMORY
135 return secure_mem_initialized;
136 #else
137 return 0;
138 #endif /* OPENSSL_NO_SECURE_MEMORY */
139 }
140
CRYPTO_secure_malloc(size_t num,const char * file,int line)141 void *CRYPTO_secure_malloc(size_t num, const char *file, int line)
142 {
143 #ifndef OPENSSL_NO_SECURE_MEMORY
144 void *ret;
145 size_t actual_size;
146
147 if (!secure_mem_initialized) {
148 return CRYPTO_malloc(num, file, line);
149 }
150 if (!CRYPTO_THREAD_write_lock(sec_malloc_lock))
151 return NULL;
152 ret = sh_malloc(num);
153 actual_size = ret ? sh_actual_size(ret) : 0;
154 secure_mem_used += actual_size;
155 CRYPTO_THREAD_unlock(sec_malloc_lock);
156 return ret;
157 #else
158 return CRYPTO_malloc(num, file, line);
159 #endif /* OPENSSL_NO_SECURE_MEMORY */
160 }
161
CRYPTO_secure_zalloc(size_t num,const char * file,int line)162 void *CRYPTO_secure_zalloc(size_t num, const char *file, int line)
163 {
164 #ifndef OPENSSL_NO_SECURE_MEMORY
165 if (secure_mem_initialized)
166 /* CRYPTO_secure_malloc() zeroes allocations when it is implemented */
167 return CRYPTO_secure_malloc(num, file, line);
168 #endif
169 return CRYPTO_zalloc(num, file, line);
170 }
171
CRYPTO_secure_free(void * ptr,const char * file,int line)172 void CRYPTO_secure_free(void *ptr, const char *file, int line)
173 {
174 #ifndef OPENSSL_NO_SECURE_MEMORY
175 size_t actual_size;
176
177 if (ptr == NULL)
178 return;
179 if (!CRYPTO_secure_allocated(ptr)) {
180 CRYPTO_free(ptr, file, line);
181 return;
182 }
183 if (!CRYPTO_THREAD_write_lock(sec_malloc_lock))
184 return;
185 actual_size = sh_actual_size(ptr);
186 CLEAR(ptr, actual_size);
187 secure_mem_used -= actual_size;
188 sh_free(ptr);
189 CRYPTO_THREAD_unlock(sec_malloc_lock);
190 #else
191 CRYPTO_free(ptr, file, line);
192 #endif /* OPENSSL_NO_SECURE_MEMORY */
193 }
194
CRYPTO_secure_clear_free(void * ptr,size_t num,const char * file,int line)195 void CRYPTO_secure_clear_free(void *ptr, size_t num,
196 const char *file, int line)
197 {
198 #ifndef OPENSSL_NO_SECURE_MEMORY
199 size_t actual_size;
200
201 if (ptr == NULL)
202 return;
203 if (!CRYPTO_secure_allocated(ptr)) {
204 OPENSSL_cleanse(ptr, num);
205 CRYPTO_free(ptr, file, line);
206 return;
207 }
208 if (!CRYPTO_THREAD_write_lock(sec_malloc_lock))
209 return;
210 actual_size = sh_actual_size(ptr);
211 CLEAR(ptr, actual_size);
212 secure_mem_used -= actual_size;
213 sh_free(ptr);
214 CRYPTO_THREAD_unlock(sec_malloc_lock);
215 #else
216 if (ptr == NULL)
217 return;
218 OPENSSL_cleanse(ptr, num);
219 CRYPTO_free(ptr, file, line);
220 #endif /* OPENSSL_NO_SECURE_MEMORY */
221 }
222
CRYPTO_secure_allocated(const void * ptr)223 int CRYPTO_secure_allocated(const void *ptr)
224 {
225 #ifndef OPENSSL_NO_SECURE_MEMORY
226 if (!secure_mem_initialized)
227 return 0;
228 /*
229 * Only read accesses to the arena take place in sh_allocated() and this
230 * is only changed by the sh_init() and sh_done() calls which are not
231 * locked. Hence, it is safe to make this check without a lock too.
232 */
233 return sh_allocated(ptr);
234 #else
235 return 0;
236 #endif /* OPENSSL_NO_SECURE_MEMORY */
237 }
238
CRYPTO_secure_used(void)239 size_t CRYPTO_secure_used(void)
240 {
241 size_t ret = 0;
242
243 #ifndef OPENSSL_NO_SECURE_MEMORY
244 if (!CRYPTO_THREAD_read_lock(sec_malloc_lock))
245 return 0;
246
247 ret = secure_mem_used;
248
249 CRYPTO_THREAD_unlock(sec_malloc_lock);
250 #endif /* OPENSSL_NO_SECURE_MEMORY */
251 return ret;
252 }
253
CRYPTO_secure_actual_size(void * ptr)254 size_t CRYPTO_secure_actual_size(void *ptr)
255 {
256 #ifndef OPENSSL_NO_SECURE_MEMORY
257 size_t actual_size;
258
259 if (!CRYPTO_THREAD_write_lock(sec_malloc_lock))
260 return 0;
261 actual_size = sh_actual_size(ptr);
262 CRYPTO_THREAD_unlock(sec_malloc_lock);
263 return actual_size;
264 #else
265 return 0;
266 #endif
267 }
268
269 /*
270 * SECURE HEAP IMPLEMENTATION
271 */
272 #ifndef OPENSSL_NO_SECURE_MEMORY
273
274
275 /*
276 * The implementation provided here uses a fixed-sized mmap() heap,
277 * which is locked into memory, not written to core files, and protected
278 * on either side by an unmapped page, which will catch pointer overruns
279 * (or underruns) and an attempt to read data out of the secure heap.
280 * Free'd memory is zero'd or otherwise cleansed.
281 *
282 * This is a pretty standard buddy allocator. We keep areas in a multiple
283 * of "sh.minsize" units. The freelist and bitmaps are kept separately,
284 * so all (and only) data is kept in the mmap'd heap.
285 *
286 * This code assumes eight-bit bytes. The numbers 3 and 7 are all over the
287 * place.
288 */
289
290 #define ONE ((size_t)1)
291
292 # define TESTBIT(t, b) (t[(b) >> 3] & (ONE << ((b) & 7)))
293 # define SETBIT(t, b) (t[(b) >> 3] |= (ONE << ((b) & 7)))
294 # define CLEARBIT(t, b) (t[(b) >> 3] &= (0xFF & ~(ONE << ((b) & 7))))
295
296 #define WITHIN_ARENA(p) \
297 ((char*)(p) >= sh.arena && (char*)(p) < &sh.arena[sh.arena_size])
298 #define WITHIN_FREELIST(p) \
299 ((char*)(p) >= (char*)sh.freelist && (char*)(p) < (char*)&sh.freelist[sh.freelist_size])
300
301
302 typedef struct sh_list_st
303 {
304 struct sh_list_st *next;
305 struct sh_list_st **p_next;
306 } SH_LIST;
307
308 typedef struct sh_st
309 {
310 char* map_result;
311 size_t map_size;
312 char *arena;
313 size_t arena_size;
314 char **freelist;
315 ossl_ssize_t freelist_size;
316 size_t minsize;
317 unsigned char *bittable;
318 unsigned char *bitmalloc;
319 size_t bittable_size; /* size in bits */
320 } SH;
321
322 static SH sh;
323
sh_getlist(char * ptr)324 static size_t sh_getlist(char *ptr)
325 {
326 ossl_ssize_t list = sh.freelist_size - 1;
327 size_t bit = (sh.arena_size + ptr - sh.arena) / sh.minsize;
328
329 for (; bit; bit >>= 1, list--) {
330 if (TESTBIT(sh.bittable, bit))
331 break;
332 OPENSSL_assert((bit & 1) == 0);
333 }
334
335 return list;
336 }
337
338
sh_testbit(char * ptr,int list,unsigned char * table)339 static int sh_testbit(char *ptr, int list, unsigned char *table)
340 {
341 size_t bit;
342
343 OPENSSL_assert(list >= 0 && list < sh.freelist_size);
344 OPENSSL_assert(((ptr - sh.arena) & ((sh.arena_size >> list) - 1)) == 0);
345 bit = (ONE << list) + ((ptr - sh.arena) / (sh.arena_size >> list));
346 OPENSSL_assert(bit > 0 && bit < sh.bittable_size);
347 return TESTBIT(table, bit);
348 }
349
sh_clearbit(char * ptr,int list,unsigned char * table)350 static void sh_clearbit(char *ptr, int list, unsigned char *table)
351 {
352 size_t bit;
353
354 OPENSSL_assert(list >= 0 && list < sh.freelist_size);
355 OPENSSL_assert(((ptr - sh.arena) & ((sh.arena_size >> list) - 1)) == 0);
356 bit = (ONE << list) + ((ptr - sh.arena) / (sh.arena_size >> list));
357 OPENSSL_assert(bit > 0 && bit < sh.bittable_size);
358 OPENSSL_assert(TESTBIT(table, bit));
359 CLEARBIT(table, bit);
360 }
361
sh_setbit(char * ptr,int list,unsigned char * table)362 static void sh_setbit(char *ptr, int list, unsigned char *table)
363 {
364 size_t bit;
365
366 OPENSSL_assert(list >= 0 && list < sh.freelist_size);
367 OPENSSL_assert(((ptr - sh.arena) & ((sh.arena_size >> list) - 1)) == 0);
368 bit = (ONE << list) + ((ptr - sh.arena) / (sh.arena_size >> list));
369 OPENSSL_assert(bit > 0 && bit < sh.bittable_size);
370 OPENSSL_assert(!TESTBIT(table, bit));
371 SETBIT(table, bit);
372 }
373
sh_add_to_list(char ** list,char * ptr)374 static void sh_add_to_list(char **list, char *ptr)
375 {
376 SH_LIST *temp;
377
378 OPENSSL_assert(WITHIN_FREELIST(list));
379 OPENSSL_assert(WITHIN_ARENA(ptr));
380
381 temp = (SH_LIST *)ptr;
382 temp->next = *(SH_LIST **)list;
383 OPENSSL_assert(temp->next == NULL || WITHIN_ARENA(temp->next));
384 temp->p_next = (SH_LIST **)list;
385
386 if (temp->next != NULL) {
387 OPENSSL_assert((char **)temp->next->p_next == list);
388 temp->next->p_next = &(temp->next);
389 }
390
391 *list = ptr;
392 }
393
sh_remove_from_list(char * ptr)394 static void sh_remove_from_list(char *ptr)
395 {
396 SH_LIST *temp, *temp2;
397
398 temp = (SH_LIST *)ptr;
399 if (temp->next != NULL)
400 temp->next->p_next = temp->p_next;
401 *temp->p_next = temp->next;
402 if (temp->next == NULL)
403 return;
404
405 temp2 = temp->next;
406 OPENSSL_assert(WITHIN_FREELIST(temp2->p_next) || WITHIN_ARENA(temp2->p_next));
407 }
408
409
sh_init(size_t size,size_t minsize)410 static int sh_init(size_t size, size_t minsize)
411 {
412 int ret;
413 size_t i;
414 size_t pgsize;
415 size_t aligned;
416 #if defined(_WIN32)
417 DWORD flOldProtect;
418 SYSTEM_INFO systemInfo;
419 #endif
420
421 memset(&sh, 0, sizeof(sh));
422
423 /* make sure size is a powers of 2 */
424 OPENSSL_assert(size > 0);
425 OPENSSL_assert((size & (size - 1)) == 0);
426 if (size == 0 || (size & (size - 1)) != 0)
427 goto err;
428
429 if (minsize <= sizeof(SH_LIST)) {
430 OPENSSL_assert(sizeof(SH_LIST) <= 65536);
431 /*
432 * Compute the minimum possible allocation size.
433 * This must be a power of 2 and at least as large as the SH_LIST
434 * structure.
435 */
436 minsize = sizeof(SH_LIST) - 1;
437 minsize |= minsize >> 1;
438 minsize |= minsize >> 2;
439 if (sizeof(SH_LIST) > 16)
440 minsize |= minsize >> 4;
441 if (sizeof(SH_LIST) > 256)
442 minsize |= minsize >> 8;
443 minsize++;
444 } else {
445 /* make sure minsize is a powers of 2 */
446 OPENSSL_assert((minsize & (minsize - 1)) == 0);
447 if ((minsize & (minsize - 1)) != 0)
448 goto err;
449 }
450
451 sh.arena_size = size;
452 sh.minsize = minsize;
453 sh.bittable_size = (sh.arena_size / sh.minsize) * 2;
454
455 /* Prevent allocations of size 0 later on */
456 if (sh.bittable_size >> 3 == 0)
457 goto err;
458
459 sh.freelist_size = -1;
460 for (i = sh.bittable_size; i; i >>= 1)
461 sh.freelist_size++;
462
463 sh.freelist = OPENSSL_zalloc(sh.freelist_size * sizeof(char *));
464 OPENSSL_assert(sh.freelist != NULL);
465 if (sh.freelist == NULL)
466 goto err;
467
468 sh.bittable = OPENSSL_zalloc(sh.bittable_size >> 3);
469 OPENSSL_assert(sh.bittable != NULL);
470 if (sh.bittable == NULL)
471 goto err;
472
473 sh.bitmalloc = OPENSSL_zalloc(sh.bittable_size >> 3);
474 OPENSSL_assert(sh.bitmalloc != NULL);
475 if (sh.bitmalloc == NULL)
476 goto err;
477
478 /* Allocate space for heap, and two extra pages as guards */
479 #if defined(_SC_PAGE_SIZE) || defined (_SC_PAGESIZE)
480 {
481 # if defined(_SC_PAGE_SIZE)
482 long tmppgsize = sysconf(_SC_PAGE_SIZE);
483 # else
484 long tmppgsize = sysconf(_SC_PAGESIZE);
485 # endif
486 if (tmppgsize < 1)
487 pgsize = PAGE_SIZE;
488 else
489 pgsize = (size_t)tmppgsize;
490 }
491 #elif defined(_WIN32)
492 GetSystemInfo(&systemInfo);
493 pgsize = (size_t)systemInfo.dwPageSize;
494 #else
495 pgsize = PAGE_SIZE;
496 #endif
497 sh.map_size = pgsize + sh.arena_size + pgsize;
498
499 #if !defined(_WIN32)
500 # ifdef MAP_ANON
501 sh.map_result = mmap(NULL, sh.map_size,
502 PROT_READ|PROT_WRITE, MAP_ANON|MAP_PRIVATE|MAP_CONCEAL, -1, 0);
503 # else
504 {
505 int fd;
506
507 sh.map_result = MAP_FAILED;
508 if ((fd = open("/dev/zero", O_RDWR)) >= 0) {
509 sh.map_result = mmap(NULL, sh.map_size,
510 PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
511 close(fd);
512 }
513 }
514 # endif
515 if (sh.map_result == MAP_FAILED)
516 goto err;
517 #else
518 sh.map_result = VirtualAlloc(NULL, sh.map_size, MEM_COMMIT | MEM_RESERVE, PAGE_READWRITE);
519
520 if (sh.map_result == NULL)
521 goto err;
522 #endif
523
524 sh.arena = (char *)(sh.map_result + pgsize);
525 sh_setbit(sh.arena, 0, sh.bittable);
526 sh_add_to_list(&sh.freelist[0], sh.arena);
527
528 /* Now try to add guard pages and lock into memory. */
529 ret = 1;
530
531 #if !defined(_WIN32)
532 /* Starting guard is already aligned from mmap. */
533 if (mprotect(sh.map_result, pgsize, PROT_NONE) < 0)
534 ret = 2;
535 #else
536 if (VirtualProtect(sh.map_result, pgsize, PAGE_NOACCESS, &flOldProtect) == FALSE)
537 ret = 2;
538 #endif
539
540 /* Ending guard page - need to round up to page boundary */
541 aligned = (pgsize + sh.arena_size + (pgsize - 1)) & ~(pgsize - 1);
542 #if !defined(_WIN32)
543 if (mprotect(sh.map_result + aligned, pgsize, PROT_NONE) < 0)
544 ret = 2;
545 #else
546 if (VirtualProtect(sh.map_result + aligned, pgsize, PAGE_NOACCESS, &flOldProtect) == FALSE)
547 ret = 2;
548 #endif
549
550 #if defined(OPENSSL_SYS_LINUX) && defined(MLOCK_ONFAULT) && defined(SYS_mlock2)
551 if (syscall(SYS_mlock2, sh.arena, sh.arena_size, MLOCK_ONFAULT) < 0) {
552 if (errno == ENOSYS) {
553 if (mlock(sh.arena, sh.arena_size) < 0)
554 ret = 2;
555 } else {
556 ret = 2;
557 }
558 }
559 #elif defined(_WIN32)
560 if (VirtualLock(sh.arena, sh.arena_size) == FALSE)
561 ret = 2;
562 #else
563 if (mlock(sh.arena, sh.arena_size) < 0)
564 ret = 2;
565 #endif
566 #ifdef MADV_DONTDUMP
567 if (madvise(sh.arena, sh.arena_size, MADV_DONTDUMP) < 0)
568 ret = 2;
569 #endif
570
571 return ret;
572
573 err:
574 sh_done();
575 return 0;
576 }
577
sh_done(void)578 static void sh_done(void)
579 {
580 OPENSSL_free(sh.freelist);
581 OPENSSL_free(sh.bittable);
582 OPENSSL_free(sh.bitmalloc);
583 #if !defined(_WIN32)
584 if (sh.map_result != MAP_FAILED && sh.map_size)
585 munmap(sh.map_result, sh.map_size);
586 #else
587 if (sh.map_result != NULL && sh.map_size)
588 VirtualFree(sh.map_result, 0, MEM_RELEASE);
589 #endif
590 memset(&sh, 0, sizeof(sh));
591 }
592
sh_allocated(const char * ptr)593 static int sh_allocated(const char *ptr)
594 {
595 return WITHIN_ARENA(ptr) ? 1 : 0;
596 }
597
sh_find_my_buddy(char * ptr,int list)598 static char *sh_find_my_buddy(char *ptr, int list)
599 {
600 size_t bit;
601 char *chunk = NULL;
602
603 bit = (ONE << list) + (ptr - sh.arena) / (sh.arena_size >> list);
604 bit ^= 1;
605
606 if (TESTBIT(sh.bittable, bit) && !TESTBIT(sh.bitmalloc, bit))
607 chunk = sh.arena + ((bit & ((ONE << list) - 1)) * (sh.arena_size >> list));
608
609 return chunk;
610 }
611
sh_malloc(size_t size)612 static void *sh_malloc(size_t size)
613 {
614 ossl_ssize_t list, slist;
615 size_t i;
616 char *chunk;
617
618 if (size > sh.arena_size)
619 return NULL;
620
621 list = sh.freelist_size - 1;
622 for (i = sh.minsize; i < size; i <<= 1)
623 list--;
624 if (list < 0)
625 return NULL;
626
627 /* try to find a larger entry to split */
628 for (slist = list; slist >= 0; slist--)
629 if (sh.freelist[slist] != NULL)
630 break;
631 if (slist < 0)
632 return NULL;
633
634 /* split larger entry */
635 while (slist != list) {
636 char *temp = sh.freelist[slist];
637
638 /* remove from bigger list */
639 OPENSSL_assert(!sh_testbit(temp, slist, sh.bitmalloc));
640 sh_clearbit(temp, slist, sh.bittable);
641 sh_remove_from_list(temp);
642 OPENSSL_assert(temp != sh.freelist[slist]);
643
644 /* done with bigger list */
645 slist++;
646
647 /* add to smaller list */
648 OPENSSL_assert(!sh_testbit(temp, slist, sh.bitmalloc));
649 sh_setbit(temp, slist, sh.bittable);
650 sh_add_to_list(&sh.freelist[slist], temp);
651 OPENSSL_assert(sh.freelist[slist] == temp);
652
653 /* split in 2 */
654 temp += sh.arena_size >> slist;
655 OPENSSL_assert(!sh_testbit(temp, slist, sh.bitmalloc));
656 sh_setbit(temp, slist, sh.bittable);
657 sh_add_to_list(&sh.freelist[slist], temp);
658 OPENSSL_assert(sh.freelist[slist] == temp);
659
660 OPENSSL_assert(temp-(sh.arena_size >> slist) == sh_find_my_buddy(temp, slist));
661 }
662
663 /* peel off memory to hand back */
664 chunk = sh.freelist[list];
665 OPENSSL_assert(sh_testbit(chunk, list, sh.bittable));
666 sh_setbit(chunk, list, sh.bitmalloc);
667 sh_remove_from_list(chunk);
668
669 OPENSSL_assert(WITHIN_ARENA(chunk));
670
671 /* zero the free list header as a precaution against information leakage */
672 memset(chunk, 0, sizeof(SH_LIST));
673
674 return chunk;
675 }
676
sh_free(void * ptr)677 static void sh_free(void *ptr)
678 {
679 size_t list;
680 void *buddy;
681
682 if (ptr == NULL)
683 return;
684 OPENSSL_assert(WITHIN_ARENA(ptr));
685 if (!WITHIN_ARENA(ptr))
686 return;
687
688 list = sh_getlist(ptr);
689 OPENSSL_assert(sh_testbit(ptr, list, sh.bittable));
690 sh_clearbit(ptr, list, sh.bitmalloc);
691 sh_add_to_list(&sh.freelist[list], ptr);
692
693 /* Try to coalesce two adjacent free areas. */
694 while ((buddy = sh_find_my_buddy(ptr, list)) != NULL) {
695 OPENSSL_assert(ptr == sh_find_my_buddy(buddy, list));
696 OPENSSL_assert(ptr != NULL);
697 OPENSSL_assert(!sh_testbit(ptr, list, sh.bitmalloc));
698 sh_clearbit(ptr, list, sh.bittable);
699 sh_remove_from_list(ptr);
700 OPENSSL_assert(!sh_testbit(ptr, list, sh.bitmalloc));
701 sh_clearbit(buddy, list, sh.bittable);
702 sh_remove_from_list(buddy);
703
704 list--;
705
706 /* Zero the higher addressed block's free list pointers */
707 memset(ptr > buddy ? ptr : buddy, 0, sizeof(SH_LIST));
708 if (ptr > buddy)
709 ptr = buddy;
710
711 OPENSSL_assert(!sh_testbit(ptr, list, sh.bitmalloc));
712 sh_setbit(ptr, list, sh.bittable);
713 sh_add_to_list(&sh.freelist[list], ptr);
714 OPENSSL_assert(sh.freelist[list] == ptr);
715 }
716 }
717
sh_actual_size(char * ptr)718 static size_t sh_actual_size(char *ptr)
719 {
720 int list;
721
722 OPENSSL_assert(WITHIN_ARENA(ptr));
723 if (!WITHIN_ARENA(ptr))
724 return 0;
725 list = sh_getlist(ptr);
726 OPENSSL_assert(sh_testbit(ptr, list, sh.bittable));
727 return sh.arena_size / (ONE << list);
728 }
729 #endif /* OPENSSL_NO_SECURE_MEMORY */
730