2 * Copyright 2015-2022 The OpenSSL Project Authors. All Rights Reserved.
3 * Copyright 2004-2014, Akamai Technologies. All Rights Reserved.
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
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").
18 #include "internal/e_os.h"
19 #include <openssl/crypto.h>
20 #include <openssl/err.h>
24 #ifndef OPENSSL_NO_SECURE_MEMORY
27 # if defined(WINAPI_FAMILY_PARTITION)
28 # if !WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_DESKTOP | WINAPI_PARTITION_SYSTEM)
30 * While VirtualLock is available under the app partition (e.g. UWP),
31 * the headers do not define the API. Define it ourselves instead.
37 _In_ LPVOID lpAddress,
45 # if defined(OPENSSL_SYS_UNIX)
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
54 # if !defined(MAP_CONCEAL)
55 # define MAP_CONCEAL 0
58 # if defined(OPENSSL_SYS_LINUX)
59 # include <sys/syscall.h>
60 # if defined(SYS_mlock2)
61 # include <linux/mman.h>
64 # include <sys/param.h>
66 # include <sys/stat.h>
70 # if defined(MADV_DONTDUMP)
71 # define HAVE_MADVISE 1
73 # define HAVE_MADVISE 0
82 #define CLEAR(p, s) OPENSSL_cleanse(p, s)
84 # define PAGE_SIZE 4096
86 #if !defined(MAP_ANON) && defined(MAP_ANONYMOUS)
87 # define MAP_ANON MAP_ANONYMOUS
90 #ifndef OPENSSL_NO_SECURE_MEMORY
91 static size_t secure_mem_used;
93 static int secure_mem_initialized;
95 static CRYPTO_RWLOCK *sec_malloc_lock = NULL;
98 * These are the functions that must be implemented by a secure heap (sh).
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);
108 int CRYPTO_secure_malloc_init(size_t size, size_t minsize)
110 #ifndef OPENSSL_NO_SECURE_MEMORY
113 if (!secure_mem_initialized) {
114 sec_malloc_lock = CRYPTO_THREAD_lock_new();
115 if (sec_malloc_lock == NULL)
117 if ((ret = sh_init(size, minsize)) != 0) {
118 secure_mem_initialized = 1;
120 CRYPTO_THREAD_lock_free(sec_malloc_lock);
121 sec_malloc_lock = NULL;
128 #endif /* OPENSSL_NO_SECURE_MEMORY */
131 int CRYPTO_secure_malloc_done(void)
133 #ifndef OPENSSL_NO_SECURE_MEMORY
134 if (secure_mem_used == 0) {
136 secure_mem_initialized = 0;
137 CRYPTO_THREAD_lock_free(sec_malloc_lock);
138 sec_malloc_lock = NULL;
141 #endif /* OPENSSL_NO_SECURE_MEMORY */
145 int CRYPTO_secure_malloc_initialized(void)
147 #ifndef OPENSSL_NO_SECURE_MEMORY
148 return secure_mem_initialized;
151 #endif /* OPENSSL_NO_SECURE_MEMORY */
154 void *CRYPTO_secure_malloc(size_t num, const char *file, int line)
156 #ifndef OPENSSL_NO_SECURE_MEMORY
159 int reason = CRYPTO_R_SECURE_MALLOC_FAILURE;
161 if (!secure_mem_initialized) {
162 return CRYPTO_malloc(num, file, line);
164 if (!CRYPTO_THREAD_write_lock(sec_malloc_lock)) {
165 reason = ERR_R_CRYPTO_LIB;
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);
173 if (ret == NULL && (file != NULL || line != 0)) {
175 ERR_set_debug(file, line, NULL);
176 ERR_set_error(ERR_LIB_CRYPTO, reason, NULL);
180 return CRYPTO_malloc(num, file, line);
181 #endif /* OPENSSL_NO_SECURE_MEMORY */
184 void *CRYPTO_secure_zalloc(size_t num, const char *file, int line)
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);
191 return CRYPTO_zalloc(num, file, line);
194 void CRYPTO_secure_free(void *ptr, const char *file, int line)
196 #ifndef OPENSSL_NO_SECURE_MEMORY
201 if (!CRYPTO_secure_allocated(ptr)) {
202 CRYPTO_free(ptr, file, line);
205 if (!CRYPTO_THREAD_write_lock(sec_malloc_lock))
207 actual_size = sh_actual_size(ptr);
208 CLEAR(ptr, actual_size);
209 secure_mem_used -= actual_size;
211 CRYPTO_THREAD_unlock(sec_malloc_lock);
213 CRYPTO_free(ptr, file, line);
214 #endif /* OPENSSL_NO_SECURE_MEMORY */
217 void CRYPTO_secure_clear_free(void *ptr, size_t num,
218 const char *file, int line)
220 #ifndef OPENSSL_NO_SECURE_MEMORY
225 if (!CRYPTO_secure_allocated(ptr)) {
226 OPENSSL_cleanse(ptr, num);
227 CRYPTO_free(ptr, file, line);
230 if (!CRYPTO_THREAD_write_lock(sec_malloc_lock))
232 actual_size = sh_actual_size(ptr);
233 CLEAR(ptr, actual_size);
234 secure_mem_used -= actual_size;
236 CRYPTO_THREAD_unlock(sec_malloc_lock);
240 OPENSSL_cleanse(ptr, num);
241 CRYPTO_free(ptr, file, line);
242 #endif /* OPENSSL_NO_SECURE_MEMORY */
245 int CRYPTO_secure_allocated(const void *ptr)
247 #ifndef OPENSSL_NO_SECURE_MEMORY
248 if (!secure_mem_initialized)
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.
255 return sh_allocated(ptr);
258 #endif /* OPENSSL_NO_SECURE_MEMORY */
261 size_t CRYPTO_secure_used(void)
263 #ifndef OPENSSL_NO_SECURE_MEMORY
264 return secure_mem_used;
267 #endif /* OPENSSL_NO_SECURE_MEMORY */
270 size_t CRYPTO_secure_actual_size(void *ptr)
272 #ifndef OPENSSL_NO_SECURE_MEMORY
275 if (!CRYPTO_THREAD_write_lock(sec_malloc_lock))
277 actual_size = sh_actual_size(ptr);
278 CRYPTO_THREAD_unlock(sec_malloc_lock);
286 * SECURE HEAP IMPLEMENTATION
288 #ifndef OPENSSL_NO_SECURE_MEMORY
292 * The implementation provided here uses a fixed-sized mmap() heap,
293 * which is locked into memory, not written to core files, and protected
294 * on either side by an unmapped page, which will catch pointer overruns
295 * (or underruns) and an attempt to read data out of the secure heap.
296 * Free'd memory is zero'd or otherwise cleansed.
298 * This is a pretty standard buddy allocator. We keep areas in a multiple
299 * of "sh.minsize" units. The freelist and bitmaps are kept separately,
300 * so all (and only) data is kept in the mmap'd heap.
302 * This code assumes eight-bit bytes. The numbers 3 and 7 are all over the
306 #define ONE ((size_t)1)
308 # define TESTBIT(t, b) (t[(b) >> 3] & (ONE << ((b) & 7)))
309 # define SETBIT(t, b) (t[(b) >> 3] |= (ONE << ((b) & 7)))
310 # define CLEARBIT(t, b) (t[(b) >> 3] &= (0xFF & ~(ONE << ((b) & 7))))
312 #define WITHIN_ARENA(p) \
313 ((char*)(p) >= sh.arena && (char*)(p) < &sh.arena[sh.arena_size])
314 #define WITHIN_FREELIST(p) \
315 ((char*)(p) >= (char*)sh.freelist && (char*)(p) < (char*)&sh.freelist[sh.freelist_size])
318 typedef struct sh_list_st
320 struct sh_list_st *next;
321 struct sh_list_st **p_next;
331 ossl_ssize_t freelist_size;
333 unsigned char *bittable;
334 unsigned char *bitmalloc;
335 size_t bittable_size; /* size in bits */
340 static size_t sh_getlist(char *ptr)
342 ossl_ssize_t list = sh.freelist_size - 1;
343 size_t bit = (sh.arena_size + ptr - sh.arena) / sh.minsize;
345 for (; bit; bit >>= 1, list--) {
346 if (TESTBIT(sh.bittable, bit))
348 OPENSSL_assert((bit & 1) == 0);
355 static int sh_testbit(char *ptr, int list, unsigned char *table)
359 OPENSSL_assert(list >= 0 && list < sh.freelist_size);
360 OPENSSL_assert(((ptr - sh.arena) & ((sh.arena_size >> list) - 1)) == 0);
361 bit = (ONE << list) + ((ptr - sh.arena) / (sh.arena_size >> list));
362 OPENSSL_assert(bit > 0 && bit < sh.bittable_size);
363 return TESTBIT(table, bit);
366 static void sh_clearbit(char *ptr, int list, unsigned char *table)
370 OPENSSL_assert(list >= 0 && list < sh.freelist_size);
371 OPENSSL_assert(((ptr - sh.arena) & ((sh.arena_size >> list) - 1)) == 0);
372 bit = (ONE << list) + ((ptr - sh.arena) / (sh.arena_size >> list));
373 OPENSSL_assert(bit > 0 && bit < sh.bittable_size);
374 OPENSSL_assert(TESTBIT(table, bit));
375 CLEARBIT(table, bit);
378 static void sh_setbit(char *ptr, int list, unsigned char *table)
382 OPENSSL_assert(list >= 0 && list < sh.freelist_size);
383 OPENSSL_assert(((ptr - sh.arena) & ((sh.arena_size >> list) - 1)) == 0);
384 bit = (ONE << list) + ((ptr - sh.arena) / (sh.arena_size >> list));
385 OPENSSL_assert(bit > 0 && bit < sh.bittable_size);
386 OPENSSL_assert(!TESTBIT(table, bit));
390 static void sh_add_to_list(char **list, char *ptr)
394 OPENSSL_assert(WITHIN_FREELIST(list));
395 OPENSSL_assert(WITHIN_ARENA(ptr));
397 temp = (SH_LIST *)ptr;
398 temp->next = *(SH_LIST **)list;
399 OPENSSL_assert(temp->next == NULL || WITHIN_ARENA(temp->next));
400 temp->p_next = (SH_LIST **)list;
402 if (temp->next != NULL) {
403 OPENSSL_assert((char **)temp->next->p_next == list);
404 temp->next->p_next = &(temp->next);
410 static void sh_remove_from_list(char *ptr)
412 SH_LIST *temp, *temp2;
414 temp = (SH_LIST *)ptr;
415 if (temp->next != NULL)
416 temp->next->p_next = temp->p_next;
417 *temp->p_next = temp->next;
418 if (temp->next == NULL)
422 OPENSSL_assert(WITHIN_FREELIST(temp2->p_next) || WITHIN_ARENA(temp2->p_next));
426 static int sh_init(size_t size, size_t minsize)
434 SYSTEM_INFO systemInfo;
437 memset(&sh, 0, sizeof(sh));
439 /* make sure size is a powers of 2 */
440 OPENSSL_assert(size > 0);
441 OPENSSL_assert((size & (size - 1)) == 0);
442 if (size == 0 || (size & (size - 1)) != 0)
445 if (minsize <= sizeof(SH_LIST)) {
446 OPENSSL_assert(sizeof(SH_LIST) <= 65536);
448 * Compute the minimum possible allocation size.
449 * This must be a power of 2 and at least as large as the SH_LIST
452 minsize = sizeof(SH_LIST) - 1;
453 minsize |= minsize >> 1;
454 minsize |= minsize >> 2;
455 if (sizeof(SH_LIST) > 16)
456 minsize |= minsize >> 4;
457 if (sizeof(SH_LIST) > 256)
458 minsize |= minsize >> 8;
461 /* make sure minsize is a powers of 2 */
462 OPENSSL_assert((minsize & (minsize - 1)) == 0);
463 if ((minsize & (minsize - 1)) != 0)
467 sh.arena_size = size;
468 sh.minsize = minsize;
469 sh.bittable_size = (sh.arena_size / sh.minsize) * 2;
471 /* Prevent allocations of size 0 later on */
472 if (sh.bittable_size >> 3 == 0)
475 sh.freelist_size = -1;
476 for (i = sh.bittable_size; i; i >>= 1)
479 sh.freelist = OPENSSL_zalloc(sh.freelist_size * sizeof(char *));
480 OPENSSL_assert(sh.freelist != NULL);
481 if (sh.freelist == NULL)
484 sh.bittable = OPENSSL_zalloc(sh.bittable_size >> 3);
485 OPENSSL_assert(sh.bittable != NULL);
486 if (sh.bittable == NULL)
489 sh.bitmalloc = OPENSSL_zalloc(sh.bittable_size >> 3);
490 OPENSSL_assert(sh.bitmalloc != NULL);
491 if (sh.bitmalloc == NULL)
494 /* Allocate space for heap, and two extra pages as guards */
495 #if defined(_SC_PAGE_SIZE) || defined (_SC_PAGESIZE)
497 # if defined(_SC_PAGE_SIZE)
498 long tmppgsize = sysconf(_SC_PAGE_SIZE);
500 long tmppgsize = sysconf(_SC_PAGESIZE);
505 pgsize = (size_t)tmppgsize;
507 #elif defined(_WIN32)
508 GetSystemInfo(&systemInfo);
509 pgsize = (size_t)systemInfo.dwPageSize;
513 sh.map_size = pgsize + sh.arena_size + pgsize;
517 sh.map_result = mmap(NULL, sh.map_size,
518 PROT_READ|PROT_WRITE, MAP_ANON|MAP_PRIVATE|MAP_CONCEAL, -1, 0);
523 sh.map_result = MAP_FAILED;
524 if ((fd = open("/dev/zero", O_RDWR)) >= 0) {
525 sh.map_result = mmap(NULL, sh.map_size,
526 PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
531 if (sh.map_result == MAP_FAILED)
534 sh.map_result = VirtualAlloc(NULL, sh.map_size, MEM_COMMIT | MEM_RESERVE, PAGE_READWRITE);
536 if (sh.map_result == NULL)
540 sh.arena = (char *)(sh.map_result + pgsize);
541 sh_setbit(sh.arena, 0, sh.bittable);
542 sh_add_to_list(&sh.freelist[0], sh.arena);
544 /* Now try to add guard pages and lock into memory. */
548 /* Starting guard is already aligned from mmap. */
549 if (mprotect(sh.map_result, pgsize, PROT_NONE) < 0)
552 if (VirtualProtect(sh.map_result, pgsize, PAGE_NOACCESS, &flOldProtect) == FALSE)
556 /* Ending guard page - need to round up to page boundary */
557 aligned = (pgsize + sh.arena_size + (pgsize - 1)) & ~(pgsize - 1);
559 if (mprotect(sh.map_result + aligned, pgsize, PROT_NONE) < 0)
562 if (VirtualProtect(sh.map_result + aligned, pgsize, PAGE_NOACCESS, &flOldProtect) == FALSE)
566 #if defined(OPENSSL_SYS_LINUX) && defined(MLOCK_ONFAULT) && defined(SYS_mlock2)
567 if (syscall(SYS_mlock2, sh.arena, sh.arena_size, MLOCK_ONFAULT) < 0) {
568 if (errno == ENOSYS) {
569 if (mlock(sh.arena, sh.arena_size) < 0)
575 #elif defined(_WIN32)
576 if (VirtualLock(sh.arena, sh.arena_size) == FALSE)
579 if (mlock(sh.arena, sh.arena_size) < 0)
583 if (madvise(sh.arena, sh.arena_size, MADV_DONTDUMP) < 0)
594 static void sh_done(void)
596 OPENSSL_free(sh.freelist);
597 OPENSSL_free(sh.bittable);
598 OPENSSL_free(sh.bitmalloc);
600 if (sh.map_result != MAP_FAILED && sh.map_size)
601 munmap(sh.map_result, sh.map_size);
603 if (sh.map_result != NULL && sh.map_size)
604 VirtualFree(sh.map_result, 0, MEM_RELEASE);
606 memset(&sh, 0, sizeof(sh));
609 static int sh_allocated(const char *ptr)
611 return WITHIN_ARENA(ptr) ? 1 : 0;
614 static char *sh_find_my_buddy(char *ptr, int list)
619 bit = (ONE << list) + (ptr - sh.arena) / (sh.arena_size >> list);
622 if (TESTBIT(sh.bittable, bit) && !TESTBIT(sh.bitmalloc, bit))
623 chunk = sh.arena + ((bit & ((ONE << list) - 1)) * (sh.arena_size >> list));
628 static void *sh_malloc(size_t size)
630 ossl_ssize_t list, slist;
634 if (size > sh.arena_size)
637 list = sh.freelist_size - 1;
638 for (i = sh.minsize; i < size; i <<= 1)
643 /* try to find a larger entry to split */
644 for (slist = list; slist >= 0; slist--)
645 if (sh.freelist[slist] != NULL)
650 /* split larger entry */
651 while (slist != list) {
652 char *temp = sh.freelist[slist];
654 /* remove from bigger list */
655 OPENSSL_assert(!sh_testbit(temp, slist, sh.bitmalloc));
656 sh_clearbit(temp, slist, sh.bittable);
657 sh_remove_from_list(temp);
658 OPENSSL_assert(temp != sh.freelist[slist]);
660 /* done with bigger list */
663 /* add to smaller list */
664 OPENSSL_assert(!sh_testbit(temp, slist, sh.bitmalloc));
665 sh_setbit(temp, slist, sh.bittable);
666 sh_add_to_list(&sh.freelist[slist], temp);
667 OPENSSL_assert(sh.freelist[slist] == temp);
670 temp += sh.arena_size >> slist;
671 OPENSSL_assert(!sh_testbit(temp, slist, sh.bitmalloc));
672 sh_setbit(temp, slist, sh.bittable);
673 sh_add_to_list(&sh.freelist[slist], temp);
674 OPENSSL_assert(sh.freelist[slist] == temp);
676 OPENSSL_assert(temp-(sh.arena_size >> slist) == sh_find_my_buddy(temp, slist));
679 /* peel off memory to hand back */
680 chunk = sh.freelist[list];
681 OPENSSL_assert(sh_testbit(chunk, list, sh.bittable));
682 sh_setbit(chunk, list, sh.bitmalloc);
683 sh_remove_from_list(chunk);
685 OPENSSL_assert(WITHIN_ARENA(chunk));
687 /* zero the free list header as a precaution against information leakage */
688 memset(chunk, 0, sizeof(SH_LIST));
693 static void sh_free(void *ptr)
700 OPENSSL_assert(WITHIN_ARENA(ptr));
701 if (!WITHIN_ARENA(ptr))
704 list = sh_getlist(ptr);
705 OPENSSL_assert(sh_testbit(ptr, list, sh.bittable));
706 sh_clearbit(ptr, list, sh.bitmalloc);
707 sh_add_to_list(&sh.freelist[list], ptr);
709 /* Try to coalesce two adjacent free areas. */
710 while ((buddy = sh_find_my_buddy(ptr, list)) != NULL) {
711 OPENSSL_assert(ptr == sh_find_my_buddy(buddy, list));
712 OPENSSL_assert(ptr != NULL);
713 OPENSSL_assert(!sh_testbit(ptr, list, sh.bitmalloc));
714 sh_clearbit(ptr, list, sh.bittable);
715 sh_remove_from_list(ptr);
716 OPENSSL_assert(!sh_testbit(ptr, list, sh.bitmalloc));
717 sh_clearbit(buddy, list, sh.bittable);
718 sh_remove_from_list(buddy);
722 /* Zero the higher addressed block's free list pointers */
723 memset(ptr > buddy ? ptr : buddy, 0, sizeof(SH_LIST));
727 OPENSSL_assert(!sh_testbit(ptr, list, sh.bitmalloc));
728 sh_setbit(ptr, list, sh.bittable);
729 sh_add_to_list(&sh.freelist[list], ptr);
730 OPENSSL_assert(sh.freelist[list] == ptr);
734 static size_t sh_actual_size(char *ptr)
738 OPENSSL_assert(WITHIN_ARENA(ptr));
739 if (!WITHIN_ARENA(ptr))
741 list = sh_getlist(ptr);
742 OPENSSL_assert(sh_testbit(ptr, list, sh.bittable));
743 return sh.arena_size / (ONE << list);
745 #endif /* OPENSSL_NO_SECURE_MEMORY */