1 /*
2 * Copyright 2015-2024 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 "internal/e_os.h"
19 #include <openssl/crypto.h>
20 #include <openssl/err.h>
21
22 #include <string.h>
23
24 #ifndef OPENSSL_NO_SECURE_MEMORY
25 # if defined(_WIN32)
26 # include <windows.h>
27 # if defined(WINAPI_FAMILY_PARTITION)
28 # if !WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_DESKTOP | WINAPI_PARTITION_SYSTEM)
29 /*
30 * While VirtualLock is available under the app partition (e.g. UWP),
31 * the headers do not define the API. Define it ourselves instead.
32 */
33 WINBASEAPI
34 BOOL
35 WINAPI
36 VirtualLock(
37 _In_ LPVOID lpAddress,
38 _In_ SIZE_T dwSize
39 );
40 # endif
41 # endif
42 # endif
43 # include <stdlib.h>
44 # include <assert.h>
45 # if defined(OPENSSL_SYS_UNIX)
46 # include <unistd.h>
47 # endif
48 # include <sys/types.h>
49 # if defined(OPENSSL_SYS_UNIX)
50 # include <sys/mman.h>
51 # if defined(__FreeBSD__)
52 # define MADV_DONTDUMP MADV_NOCORE
53 # endif
54 # if !defined(MAP_CONCEAL)
55 # define MAP_CONCEAL 0
56 # endif
57 # endif
58 # if defined(OPENSSL_SYS_LINUX)
59 # include <sys/syscall.h>
60 # if defined(SYS_mlock2)
61 # include <linux/mman.h>
62 # include <errno.h>
63 # endif
64 # include <sys/param.h>
65 # endif
66 # include <sys/stat.h>
67 # include <fcntl.h>
68 #endif
69 #ifndef HAVE_MADVISE
70 # if defined(MADV_DONTDUMP)
71 # define HAVE_MADVISE 1
72 # else
73 # define HAVE_MADVISE 0
74 # endif
75 #endif
76 #if HAVE_MADVISE
77 # undef NO_MADVISE
78 #else
79 # define NO_MADVISE
80 #endif
81
82 #define CLEAR(p, s) OPENSSL_cleanse(p, s)
83 #ifndef PAGE_SIZE
84 # define PAGE_SIZE 4096
85 #endif
86 #if !defined(MAP_ANON) && defined(MAP_ANONYMOUS)
87 # define MAP_ANON MAP_ANONYMOUS
88 #endif
89
90 #ifndef OPENSSL_NO_SECURE_MEMORY
91 static size_t secure_mem_used;
92
93 static int secure_mem_initialized;
94
95 static CRYPTO_RWLOCK *sec_malloc_lock = NULL;
96
97 /*
98 * These are the functions that must be implemented by a secure heap (sh).
99 */
100 static int sh_init(size_t size, size_t minsize);
101 static void *sh_malloc(size_t size);
102 static void sh_free(void *ptr);
103 static void sh_done(void);
104 static size_t sh_actual_size(char *ptr);
105 static int sh_allocated(const char *ptr);
106 #endif
107
CRYPTO_secure_malloc_init(size_t size,size_t minsize)108 int CRYPTO_secure_malloc_init(size_t size, size_t minsize)
109 {
110 #ifndef OPENSSL_NO_SECURE_MEMORY
111 int ret = 0;
112
113 if (!secure_mem_initialized) {
114 sec_malloc_lock = CRYPTO_THREAD_lock_new();
115 if (sec_malloc_lock == NULL)
116 return 0;
117 if ((ret = sh_init(size, minsize)) != 0) {
118 secure_mem_initialized = 1;
119 } else {
120 CRYPTO_THREAD_lock_free(sec_malloc_lock);
121 sec_malloc_lock = NULL;
122 }
123 }
124
125 return ret;
126 #else
127 return 0;
128 #endif /* OPENSSL_NO_SECURE_MEMORY */
129 }
130
CRYPTO_secure_malloc_done(void)131 int CRYPTO_secure_malloc_done(void)
132 {
133 #ifndef OPENSSL_NO_SECURE_MEMORY
134 if (secure_mem_used == 0) {
135 sh_done();
136 secure_mem_initialized = 0;
137 CRYPTO_THREAD_lock_free(sec_malloc_lock);
138 sec_malloc_lock = NULL;
139 return 1;
140 }
141 #endif /* OPENSSL_NO_SECURE_MEMORY */
142 return 0;
143 }
144
CRYPTO_secure_malloc_initialized(void)145 int CRYPTO_secure_malloc_initialized(void)
146 {
147 #ifndef OPENSSL_NO_SECURE_MEMORY
148 return secure_mem_initialized;
149 #else
150 return 0;
151 #endif /* OPENSSL_NO_SECURE_MEMORY */
152 }
153
CRYPTO_secure_malloc(size_t num,const char * file,int line)154 void *CRYPTO_secure_malloc(size_t num, const char *file, int line)
155 {
156 #ifndef OPENSSL_NO_SECURE_MEMORY
157 void *ret = NULL;
158 size_t actual_size;
159 int reason = CRYPTO_R_SECURE_MALLOC_FAILURE;
160
161 if (!secure_mem_initialized) {
162 return CRYPTO_malloc(num, file, line);
163 }
164 if (!CRYPTO_THREAD_write_lock(sec_malloc_lock)) {
165 reason = ERR_R_CRYPTO_LIB;
166 goto err;
167 }
168 ret = sh_malloc(num);
169 actual_size = ret ? sh_actual_size(ret) : 0;
170 secure_mem_used += actual_size;
171 CRYPTO_THREAD_unlock(sec_malloc_lock);
172 err:
173 if (ret == NULL && (file != NULL || line != 0)) {
174 ERR_new();
175 ERR_set_debug(file, line, NULL);
176 ERR_set_error(ERR_LIB_CRYPTO, reason, NULL);
177 }
178 return ret;
179 #else
180 return CRYPTO_malloc(num, file, line);
181 #endif /* OPENSSL_NO_SECURE_MEMORY */
182 }
183
CRYPTO_secure_zalloc(size_t num,const char * file,int line)184 void *CRYPTO_secure_zalloc(size_t num, const char *file, int line)
185 {
186 #ifndef OPENSSL_NO_SECURE_MEMORY
187 if (secure_mem_initialized)
188 /* CRYPTO_secure_malloc() zeroes allocations when it is implemented */
189 return CRYPTO_secure_malloc(num, file, line);
190 #endif
191 return CRYPTO_zalloc(num, file, line);
192 }
193
CRYPTO_secure_free(void * ptr,const char * file,int line)194 void CRYPTO_secure_free(void *ptr, const char *file, int line)
195 {
196 #ifndef OPENSSL_NO_SECURE_MEMORY
197 size_t actual_size;
198
199 if (ptr == NULL)
200 return;
201 if (!CRYPTO_secure_allocated(ptr)) {
202 CRYPTO_free(ptr, file, line);
203 return;
204 }
205 if (!CRYPTO_THREAD_write_lock(sec_malloc_lock))
206 return;
207 actual_size = sh_actual_size(ptr);
208 CLEAR(ptr, actual_size);
209 secure_mem_used -= actual_size;
210 sh_free(ptr);
211 CRYPTO_THREAD_unlock(sec_malloc_lock);
212 #else
213 CRYPTO_free(ptr, file, line);
214 #endif /* OPENSSL_NO_SECURE_MEMORY */
215 }
216
CRYPTO_secure_clear_free(void * ptr,size_t num,const char * file,int line)217 void CRYPTO_secure_clear_free(void *ptr, size_t num,
218 const char *file, int line)
219 {
220 #ifndef OPENSSL_NO_SECURE_MEMORY
221 size_t actual_size;
222
223 if (ptr == NULL)
224 return;
225 if (!CRYPTO_secure_allocated(ptr)) {
226 OPENSSL_cleanse(ptr, num);
227 CRYPTO_free(ptr, file, line);
228 return;
229 }
230 if (!CRYPTO_THREAD_write_lock(sec_malloc_lock))
231 return;
232 actual_size = sh_actual_size(ptr);
233 CLEAR(ptr, actual_size);
234 secure_mem_used -= actual_size;
235 sh_free(ptr);
236 CRYPTO_THREAD_unlock(sec_malloc_lock);
237 #else
238 if (ptr == NULL)
239 return;
240 OPENSSL_cleanse(ptr, num);
241 CRYPTO_free(ptr, file, line);
242 #endif /* OPENSSL_NO_SECURE_MEMORY */
243 }
244
CRYPTO_secure_allocated(const void * ptr)245 int CRYPTO_secure_allocated(const void *ptr)
246 {
247 #ifndef OPENSSL_NO_SECURE_MEMORY
248 if (!secure_mem_initialized)
249 return 0;
250 /*
251 * Only read accesses to the arena take place in sh_allocated() and this
252 * is only changed by the sh_init() and sh_done() calls which are not
253 * locked. Hence, it is safe to make this check without a lock too.
254 */
255 return sh_allocated(ptr);
256 #else
257 return 0;
258 #endif /* OPENSSL_NO_SECURE_MEMORY */
259 }
260
CRYPTO_secure_used(void)261 size_t CRYPTO_secure_used(void)
262 {
263 size_t ret = 0;
264
265 #ifndef OPENSSL_NO_SECURE_MEMORY
266 if (!CRYPTO_THREAD_read_lock(sec_malloc_lock))
267 return 0;
268
269 ret = secure_mem_used;
270
271 CRYPTO_THREAD_unlock(sec_malloc_lock);
272 #endif /* OPENSSL_NO_SECURE_MEMORY */
273 return ret;
274 }
275
CRYPTO_secure_actual_size(void * ptr)276 size_t CRYPTO_secure_actual_size(void *ptr)
277 {
278 #ifndef OPENSSL_NO_SECURE_MEMORY
279 size_t actual_size;
280
281 if (!CRYPTO_THREAD_write_lock(sec_malloc_lock))
282 return 0;
283 actual_size = sh_actual_size(ptr);
284 CRYPTO_THREAD_unlock(sec_malloc_lock);
285 return actual_size;
286 #else
287 return 0;
288 #endif
289 }
290
291 /*
292 * SECURE HEAP IMPLEMENTATION
293 */
294 #ifndef OPENSSL_NO_SECURE_MEMORY
295
296
297 /*
298 * The implementation provided here uses a fixed-sized mmap() heap,
299 * which is locked into memory, not written to core files, and protected
300 * on either side by an unmapped page, which will catch pointer overruns
301 * (or underruns) and an attempt to read data out of the secure heap.
302 * Free'd memory is zero'd or otherwise cleansed.
303 *
304 * This is a pretty standard buddy allocator. We keep areas in a multiple
305 * of "sh.minsize" units. The freelist and bitmaps are kept separately,
306 * so all (and only) data is kept in the mmap'd heap.
307 *
308 * This code assumes eight-bit bytes. The numbers 3 and 7 are all over the
309 * place.
310 */
311
312 #define ONE ((size_t)1)
313
314 # define TESTBIT(t, b) (t[(b) >> 3] & (ONE << ((b) & 7)))
315 # define SETBIT(t, b) (t[(b) >> 3] |= (ONE << ((b) & 7)))
316 # define CLEARBIT(t, b) (t[(b) >> 3] &= (0xFF & ~(ONE << ((b) & 7))))
317
318 #define WITHIN_ARENA(p) \
319 ((char*)(p) >= sh.arena && (char*)(p) < &sh.arena[sh.arena_size])
320 #define WITHIN_FREELIST(p) \
321 ((char*)(p) >= (char*)sh.freelist && (char*)(p) < (char*)&sh.freelist[sh.freelist_size])
322
323
324 typedef struct sh_list_st {
325 struct sh_list_st *next;
326 struct sh_list_st **p_next;
327 } SH_LIST;
328
329 typedef struct sh_st {
330 char* map_result;
331 size_t map_size;
332 char *arena;
333 size_t arena_size;
334 char **freelist;
335 ossl_ssize_t freelist_size;
336 size_t minsize;
337 unsigned char *bittable;
338 unsigned char *bitmalloc;
339 size_t bittable_size; /* size in bits */
340 } SH;
341
342 static SH sh;
343
sh_getlist(char * ptr)344 static size_t sh_getlist(char *ptr)
345 {
346 ossl_ssize_t list = sh.freelist_size - 1;
347 size_t bit = (sh.arena_size + ptr - sh.arena) / sh.minsize;
348
349 for (; bit; bit >>= 1, list--) {
350 if (TESTBIT(sh.bittable, bit))
351 break;
352 OPENSSL_assert((bit & 1) == 0);
353 }
354
355 return list;
356 }
357
358
sh_testbit(char * ptr,int list,unsigned char * table)359 static int sh_testbit(char *ptr, int list, unsigned char *table)
360 {
361 size_t bit;
362
363 OPENSSL_assert(list >= 0 && list < sh.freelist_size);
364 OPENSSL_assert(((ptr - sh.arena) & ((sh.arena_size >> list) - 1)) == 0);
365 bit = (ONE << list) + ((ptr - sh.arena) / (sh.arena_size >> list));
366 OPENSSL_assert(bit > 0 && bit < sh.bittable_size);
367 return TESTBIT(table, bit);
368 }
369
sh_clearbit(char * ptr,int list,unsigned char * table)370 static void sh_clearbit(char *ptr, int list, unsigned char *table)
371 {
372 size_t bit;
373
374 OPENSSL_assert(list >= 0 && list < sh.freelist_size);
375 OPENSSL_assert(((ptr - sh.arena) & ((sh.arena_size >> list) - 1)) == 0);
376 bit = (ONE << list) + ((ptr - sh.arena) / (sh.arena_size >> list));
377 OPENSSL_assert(bit > 0 && bit < sh.bittable_size);
378 OPENSSL_assert(TESTBIT(table, bit));
379 CLEARBIT(table, bit);
380 }
381
sh_setbit(char * ptr,int list,unsigned char * table)382 static void sh_setbit(char *ptr, int list, unsigned char *table)
383 {
384 size_t bit;
385
386 OPENSSL_assert(list >= 0 && list < sh.freelist_size);
387 OPENSSL_assert(((ptr - sh.arena) & ((sh.arena_size >> list) - 1)) == 0);
388 bit = (ONE << list) + ((ptr - sh.arena) / (sh.arena_size >> list));
389 OPENSSL_assert(bit > 0 && bit < sh.bittable_size);
390 OPENSSL_assert(!TESTBIT(table, bit));
391 SETBIT(table, bit);
392 }
393
sh_add_to_list(char ** list,char * ptr)394 static void sh_add_to_list(char **list, char *ptr)
395 {
396 SH_LIST *temp;
397
398 OPENSSL_assert(WITHIN_FREELIST(list));
399 OPENSSL_assert(WITHIN_ARENA(ptr));
400
401 temp = (SH_LIST *)ptr;
402 temp->next = *(SH_LIST **)list;
403 OPENSSL_assert(temp->next == NULL || WITHIN_ARENA(temp->next));
404 temp->p_next = (SH_LIST **)list;
405
406 if (temp->next != NULL) {
407 OPENSSL_assert((char **)temp->next->p_next == list);
408 temp->next->p_next = &(temp->next);
409 }
410
411 *list = ptr;
412 }
413
sh_remove_from_list(char * ptr)414 static void sh_remove_from_list(char *ptr)
415 {
416 SH_LIST *temp, *temp2;
417
418 temp = (SH_LIST *)ptr;
419 if (temp->next != NULL)
420 temp->next->p_next = temp->p_next;
421 *temp->p_next = temp->next;
422 if (temp->next == NULL)
423 return;
424
425 temp2 = temp->next;
426 OPENSSL_assert(WITHIN_FREELIST(temp2->p_next) || WITHIN_ARENA(temp2->p_next));
427 }
428
429
sh_init(size_t size,size_t minsize)430 static int sh_init(size_t size, size_t minsize)
431 {
432 int ret;
433 size_t i;
434 size_t pgsize;
435 size_t aligned;
436 #if defined(_WIN32)
437 DWORD flOldProtect;
438 SYSTEM_INFO systemInfo;
439 #endif
440
441 memset(&sh, 0, sizeof(sh));
442
443 /* make sure size is a powers of 2 */
444 OPENSSL_assert(size > 0);
445 OPENSSL_assert((size & (size - 1)) == 0);
446 if (size == 0 || (size & (size - 1)) != 0)
447 goto err;
448
449 if (minsize <= sizeof(SH_LIST)) {
450 OPENSSL_assert(sizeof(SH_LIST) <= 65536);
451 /*
452 * Compute the minimum possible allocation size.
453 * This must be a power of 2 and at least as large as the SH_LIST
454 * structure.
455 */
456 minsize = sizeof(SH_LIST) - 1;
457 minsize |= minsize >> 1;
458 minsize |= minsize >> 2;
459 if (sizeof(SH_LIST) > 16)
460 minsize |= minsize >> 4;
461 if (sizeof(SH_LIST) > 256)
462 minsize |= minsize >> 8;
463 minsize++;
464 } else {
465 /* make sure minsize is a powers of 2 */
466 OPENSSL_assert((minsize & (minsize - 1)) == 0);
467 if ((minsize & (minsize - 1)) != 0)
468 goto err;
469 }
470
471 sh.arena_size = size;
472 sh.minsize = minsize;
473 sh.bittable_size = (sh.arena_size / sh.minsize) * 2;
474
475 /* Prevent allocations of size 0 later on */
476 if (sh.bittable_size >> 3 == 0)
477 goto err;
478
479 sh.freelist_size = -1;
480 for (i = sh.bittable_size; i; i >>= 1)
481 sh.freelist_size++;
482
483 sh.freelist = OPENSSL_zalloc(sh.freelist_size * sizeof(char *));
484 OPENSSL_assert(sh.freelist != NULL);
485 if (sh.freelist == NULL)
486 goto err;
487
488 sh.bittable = OPENSSL_zalloc(sh.bittable_size >> 3);
489 OPENSSL_assert(sh.bittable != NULL);
490 if (sh.bittable == NULL)
491 goto err;
492
493 sh.bitmalloc = OPENSSL_zalloc(sh.bittable_size >> 3);
494 OPENSSL_assert(sh.bitmalloc != NULL);
495 if (sh.bitmalloc == NULL)
496 goto err;
497
498 /* Allocate space for heap, and two extra pages as guards */
499 #if defined(_SC_PAGE_SIZE) || defined (_SC_PAGESIZE)
500 {
501 # if defined(_SC_PAGE_SIZE)
502 long tmppgsize = sysconf(_SC_PAGE_SIZE);
503 # else
504 long tmppgsize = sysconf(_SC_PAGESIZE);
505 # endif
506 if (tmppgsize < 1)
507 pgsize = PAGE_SIZE;
508 else
509 pgsize = (size_t)tmppgsize;
510 }
511 #elif defined(_WIN32)
512 GetSystemInfo(&systemInfo);
513 pgsize = (size_t)systemInfo.dwPageSize;
514 #else
515 pgsize = PAGE_SIZE;
516 #endif
517 sh.map_size = pgsize + sh.arena_size + pgsize;
518
519 #if !defined(_WIN32)
520 # ifdef MAP_ANON
521 sh.map_result = mmap(NULL, sh.map_size,
522 PROT_READ|PROT_WRITE, MAP_ANON|MAP_PRIVATE|MAP_CONCEAL, -1, 0);
523 # else
524 {
525 int fd;
526
527 sh.map_result = MAP_FAILED;
528 if ((fd = open("/dev/zero", O_RDWR)) >= 0) {
529 sh.map_result = mmap(NULL, sh.map_size,
530 PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
531 close(fd);
532 }
533 }
534 # endif
535 if (sh.map_result == MAP_FAILED)
536 goto err;
537 #else
538 sh.map_result = VirtualAlloc(NULL, sh.map_size, MEM_COMMIT | MEM_RESERVE, PAGE_READWRITE);
539
540 if (sh.map_result == NULL)
541 goto err;
542 #endif
543
544 sh.arena = (char *)(sh.map_result + pgsize);
545 sh_setbit(sh.arena, 0, sh.bittable);
546 sh_add_to_list(&sh.freelist[0], sh.arena);
547
548 /* Now try to add guard pages and lock into memory. */
549 ret = 1;
550
551 #if !defined(_WIN32)
552 /* Starting guard is already aligned from mmap. */
553 if (mprotect(sh.map_result, pgsize, PROT_NONE) < 0)
554 ret = 2;
555 #else
556 if (VirtualProtect(sh.map_result, pgsize, PAGE_NOACCESS, &flOldProtect) == FALSE)
557 ret = 2;
558 #endif
559
560 /* Ending guard page - need to round up to page boundary */
561 aligned = (pgsize + sh.arena_size + (pgsize - 1)) & ~(pgsize - 1);
562 #if !defined(_WIN32)
563 if (mprotect(sh.map_result + aligned, pgsize, PROT_NONE) < 0)
564 ret = 2;
565 #else
566 if (VirtualProtect(sh.map_result + aligned, pgsize, PAGE_NOACCESS, &flOldProtect) == FALSE)
567 ret = 2;
568 #endif
569
570 #if defined(OPENSSL_SYS_LINUX) && defined(MLOCK_ONFAULT) && defined(SYS_mlock2)
571 if (syscall(SYS_mlock2, sh.arena, sh.arena_size, MLOCK_ONFAULT) < 0) {
572 if (errno == ENOSYS) {
573 if (mlock(sh.arena, sh.arena_size) < 0)
574 ret = 2;
575 } else {
576 ret = 2;
577 }
578 }
579 #elif defined(_WIN32)
580 if (VirtualLock(sh.arena, sh.arena_size) == FALSE)
581 ret = 2;
582 #else
583 if (mlock(sh.arena, sh.arena_size) < 0)
584 ret = 2;
585 #endif
586 #ifndef NO_MADVISE
587 if (madvise(sh.arena, sh.arena_size, MADV_DONTDUMP) < 0)
588 ret = 2;
589 #endif
590
591 return ret;
592
593 err:
594 sh_done();
595 return 0;
596 }
597
sh_done(void)598 static void sh_done(void)
599 {
600 OPENSSL_free(sh.freelist);
601 OPENSSL_free(sh.bittable);
602 OPENSSL_free(sh.bitmalloc);
603 #if !defined(_WIN32)
604 if (sh.map_result != MAP_FAILED && sh.map_size)
605 munmap(sh.map_result, sh.map_size);
606 #else
607 if (sh.map_result != NULL && sh.map_size)
608 VirtualFree(sh.map_result, 0, MEM_RELEASE);
609 #endif
610 memset(&sh, 0, sizeof(sh));
611 }
612
sh_allocated(const char * ptr)613 static int sh_allocated(const char *ptr)
614 {
615 return WITHIN_ARENA(ptr) ? 1 : 0;
616 }
617
sh_find_my_buddy(char * ptr,int list)618 static char *sh_find_my_buddy(char *ptr, int list)
619 {
620 size_t bit;
621 char *chunk = NULL;
622
623 bit = (ONE << list) + (ptr - sh.arena) / (sh.arena_size >> list);
624 bit ^= 1;
625
626 if (TESTBIT(sh.bittable, bit) && !TESTBIT(sh.bitmalloc, bit))
627 chunk = sh.arena + ((bit & ((ONE << list) - 1)) * (sh.arena_size >> list));
628
629 return chunk;
630 }
631
sh_malloc(size_t size)632 static void *sh_malloc(size_t size)
633 {
634 ossl_ssize_t list, slist;
635 size_t i;
636 char *chunk;
637
638 if (size > sh.arena_size)
639 return NULL;
640
641 list = sh.freelist_size - 1;
642 for (i = sh.minsize; i < size; i <<= 1)
643 list--;
644 if (list < 0)
645 return NULL;
646
647 /* try to find a larger entry to split */
648 for (slist = list; slist >= 0; slist--)
649 if (sh.freelist[slist] != NULL)
650 break;
651 if (slist < 0)
652 return NULL;
653
654 /* split larger entry */
655 while (slist != list) {
656 char *temp = sh.freelist[slist];
657
658 /* remove from bigger list */
659 OPENSSL_assert(!sh_testbit(temp, slist, sh.bitmalloc));
660 sh_clearbit(temp, slist, sh.bittable);
661 sh_remove_from_list(temp);
662 OPENSSL_assert(temp != sh.freelist[slist]);
663
664 /* done with bigger list */
665 slist++;
666
667 /* add to smaller list */
668 OPENSSL_assert(!sh_testbit(temp, slist, sh.bitmalloc));
669 sh_setbit(temp, slist, sh.bittable);
670 sh_add_to_list(&sh.freelist[slist], temp);
671 OPENSSL_assert(sh.freelist[slist] == temp);
672
673 /* split in 2 */
674 temp += sh.arena_size >> slist;
675 OPENSSL_assert(!sh_testbit(temp, slist, sh.bitmalloc));
676 sh_setbit(temp, slist, sh.bittable);
677 sh_add_to_list(&sh.freelist[slist], temp);
678 OPENSSL_assert(sh.freelist[slist] == temp);
679
680 OPENSSL_assert(temp-(sh.arena_size >> slist) == sh_find_my_buddy(temp, slist));
681 }
682
683 /* peel off memory to hand back */
684 chunk = sh.freelist[list];
685 OPENSSL_assert(sh_testbit(chunk, list, sh.bittable));
686 sh_setbit(chunk, list, sh.bitmalloc);
687 sh_remove_from_list(chunk);
688
689 OPENSSL_assert(WITHIN_ARENA(chunk));
690
691 /* zero the free list header as a precaution against information leakage */
692 memset(chunk, 0, sizeof(SH_LIST));
693
694 return chunk;
695 }
696
sh_free(void * ptr)697 static void sh_free(void *ptr)
698 {
699 size_t list;
700 void *buddy;
701
702 if (ptr == NULL)
703 return;
704 OPENSSL_assert(WITHIN_ARENA(ptr));
705 if (!WITHIN_ARENA(ptr))
706 return;
707
708 list = sh_getlist(ptr);
709 OPENSSL_assert(sh_testbit(ptr, list, sh.bittable));
710 sh_clearbit(ptr, list, sh.bitmalloc);
711 sh_add_to_list(&sh.freelist[list], ptr);
712
713 /* Try to coalesce two adjacent free areas. */
714 while ((buddy = sh_find_my_buddy(ptr, list)) != NULL) {
715 OPENSSL_assert(ptr == sh_find_my_buddy(buddy, list));
716 OPENSSL_assert(ptr != NULL);
717 OPENSSL_assert(!sh_testbit(ptr, list, sh.bitmalloc));
718 sh_clearbit(ptr, list, sh.bittable);
719 sh_remove_from_list(ptr);
720 OPENSSL_assert(!sh_testbit(ptr, list, sh.bitmalloc));
721 sh_clearbit(buddy, list, sh.bittable);
722 sh_remove_from_list(buddy);
723
724 list--;
725
726 /* Zero the higher addressed block's free list pointers */
727 memset(ptr > buddy ? ptr : buddy, 0, sizeof(SH_LIST));
728 if (ptr > buddy)
729 ptr = buddy;
730
731 OPENSSL_assert(!sh_testbit(ptr, list, sh.bitmalloc));
732 sh_setbit(ptr, list, sh.bittable);
733 sh_add_to_list(&sh.freelist[list], ptr);
734 OPENSSL_assert(sh.freelist[list] == ptr);
735 }
736 }
737
sh_actual_size(char * ptr)738 static size_t sh_actual_size(char *ptr)
739 {
740 int list;
741
742 OPENSSL_assert(WITHIN_ARENA(ptr));
743 if (!WITHIN_ARENA(ptr))
744 return 0;
745 list = sh_getlist(ptr);
746 OPENSSL_assert(sh_testbit(ptr, list, sh.bittable));
747 return sh.arena_size / (ONE << list);
748 }
749 #endif /* OPENSSL_NO_SECURE_MEMORY */
750
