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>
23 #ifndef OPENSSL_NO_SECURE_MEMORY
26 # if defined(WINAPI_FAMILY_PARTITION) \
27 && !WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_DESKTOP | WINAPI_PARTITION_SYSTEM)
29 * While VirtualLock is available under the app partition (e.g. UWP),
30 * the headers do not define the API. Define it ourselves instead.
36 _In_ LPVOID lpAddress
,
43 # if defined(OPENSSL_SYS_UNIX)
46 # include <sys/types.h>
47 # if defined(OPENSSL_SYS_UNIX)
48 # include <sys/mman.h>
49 # if defined(__FreeBSD__)
50 # define MADV_DONTDUMP MADV_NOCORE
52 # if !defined(MAP_CONCEAL)
53 # define MAP_CONCEAL 0
56 # if defined(OPENSSL_SYS_LINUX)
57 # include <sys/syscall.h>
58 # if defined(SYS_mlock2)
59 # include <linux/mman.h>
62 # include <sys/param.h>
64 # include <sys/stat.h>
68 #define CLEAR(p, s) OPENSSL_cleanse(p, s)
70 # define PAGE_SIZE 4096
72 #if !defined(MAP_ANON) && defined(MAP_ANONYMOUS)
73 # define MAP_ANON MAP_ANONYMOUS
76 #ifndef OPENSSL_NO_SECURE_MEMORY
77 static size_t secure_mem_used
;
79 static int secure_mem_initialized
;
81 static CRYPTO_RWLOCK
*sec_malloc_lock
= NULL
;
84 * These are the functions that must be implemented by a secure heap (sh).
86 static int sh_init(size_t size
, size_t minsize
);
87 static void *sh_malloc(size_t size
);
88 static void sh_free(void *ptr
);
89 static void sh_done(void);
90 static size_t sh_actual_size(char *ptr
);
91 static int sh_allocated(const char *ptr
);
94 int CRYPTO_secure_malloc_init(size_t size
, size_t minsize
)
96 #ifndef OPENSSL_NO_SECURE_MEMORY
99 if (!secure_mem_initialized
) {
100 sec_malloc_lock
= CRYPTO_THREAD_lock_new();
101 if (sec_malloc_lock
== NULL
)
103 if ((ret
= sh_init(size
, minsize
)) != 0) {
104 secure_mem_initialized
= 1;
106 CRYPTO_THREAD_lock_free(sec_malloc_lock
);
107 sec_malloc_lock
= NULL
;
114 #endif /* OPENSSL_NO_SECURE_MEMORY */
117 int CRYPTO_secure_malloc_done(void)
119 #ifndef OPENSSL_NO_SECURE_MEMORY
120 if (secure_mem_used
== 0) {
122 secure_mem_initialized
= 0;
123 CRYPTO_THREAD_lock_free(sec_malloc_lock
);
124 sec_malloc_lock
= NULL
;
127 #endif /* OPENSSL_NO_SECURE_MEMORY */
131 int CRYPTO_secure_malloc_initialized(void)
133 #ifndef OPENSSL_NO_SECURE_MEMORY
134 return secure_mem_initialized
;
137 #endif /* OPENSSL_NO_SECURE_MEMORY */
140 void *CRYPTO_secure_malloc(size_t num
, const char *file
, int line
)
142 #ifndef OPENSSL_NO_SECURE_MEMORY
146 if (!secure_mem_initialized
) {
147 return CRYPTO_malloc(num
, file
, line
);
149 if (!CRYPTO_THREAD_write_lock(sec_malloc_lock
))
151 ret
= sh_malloc(num
);
152 actual_size
= ret
? sh_actual_size(ret
) : 0;
153 secure_mem_used
+= actual_size
;
154 CRYPTO_THREAD_unlock(sec_malloc_lock
);
157 return CRYPTO_malloc(num
, file
, line
);
158 #endif /* OPENSSL_NO_SECURE_MEMORY */
161 void *CRYPTO_secure_zalloc(size_t num
, const char *file
, int line
)
163 #ifndef OPENSSL_NO_SECURE_MEMORY
164 if (secure_mem_initialized
)
165 /* CRYPTO_secure_malloc() zeroes allocations when it is implemented */
166 return CRYPTO_secure_malloc(num
, file
, line
);
168 return CRYPTO_zalloc(num
, file
, line
);
171 void CRYPTO_secure_free(void *ptr
, const char *file
, int line
)
173 #ifndef OPENSSL_NO_SECURE_MEMORY
178 if (!CRYPTO_secure_allocated(ptr
)) {
179 CRYPTO_free(ptr
, file
, line
);
182 if (!CRYPTO_THREAD_write_lock(sec_malloc_lock
))
184 actual_size
= sh_actual_size(ptr
);
185 CLEAR(ptr
, actual_size
);
186 secure_mem_used
-= actual_size
;
188 CRYPTO_THREAD_unlock(sec_malloc_lock
);
190 CRYPTO_free(ptr
, file
, line
);
191 #endif /* OPENSSL_NO_SECURE_MEMORY */
194 void CRYPTO_secure_clear_free(void *ptr
, size_t num
,
195 const char *file
, int line
)
197 #ifndef OPENSSL_NO_SECURE_MEMORY
202 if (!CRYPTO_secure_allocated(ptr
)) {
203 OPENSSL_cleanse(ptr
, num
);
204 CRYPTO_free(ptr
, file
, line
);
207 if (!CRYPTO_THREAD_write_lock(sec_malloc_lock
))
209 actual_size
= sh_actual_size(ptr
);
210 CLEAR(ptr
, actual_size
);
211 secure_mem_used
-= actual_size
;
213 CRYPTO_THREAD_unlock(sec_malloc_lock
);
217 OPENSSL_cleanse(ptr
, num
);
218 CRYPTO_free(ptr
, file
, line
);
219 #endif /* OPENSSL_NO_SECURE_MEMORY */
222 int CRYPTO_secure_allocated(const void *ptr
)
224 #ifndef OPENSSL_NO_SECURE_MEMORY
225 if (!secure_mem_initialized
)
228 * Only read accesses to the arena take place in sh_allocated() and this
229 * is only changed by the sh_init() and sh_done() calls which are not
230 * locked. Hence, it is safe to make this check without a lock too.
232 return sh_allocated(ptr
);
235 #endif /* OPENSSL_NO_SECURE_MEMORY */
238 size_t CRYPTO_secure_used(void)
240 #ifndef OPENSSL_NO_SECURE_MEMORY
241 return secure_mem_used
;
244 #endif /* OPENSSL_NO_SECURE_MEMORY */
247 size_t CRYPTO_secure_actual_size(void *ptr
)
249 #ifndef OPENSSL_NO_SECURE_MEMORY
252 if (!CRYPTO_THREAD_write_lock(sec_malloc_lock
))
254 actual_size
= sh_actual_size(ptr
);
255 CRYPTO_THREAD_unlock(sec_malloc_lock
);
263 * SECURE HEAP IMPLEMENTATION
265 #ifndef OPENSSL_NO_SECURE_MEMORY
269 * The implementation provided here uses a fixed-sized mmap() heap,
270 * which is locked into memory, not written to core files, and protected
271 * on either side by an unmapped page, which will catch pointer overruns
272 * (or underruns) and an attempt to read data out of the secure heap.
273 * Free'd memory is zero'd or otherwise cleansed.
275 * This is a pretty standard buddy allocator. We keep areas in a multiple
276 * of "sh.minsize" units. The freelist and bitmaps are kept separately,
277 * so all (and only) data is kept in the mmap'd heap.
279 * This code assumes eight-bit bytes. The numbers 3 and 7 are all over the
283 #define ONE ((size_t)1)
285 # define TESTBIT(t, b) (t[(b) >> 3] & (ONE << ((b) & 7)))
286 # define SETBIT(t, b) (t[(b) >> 3] |= (ONE << ((b) & 7)))
287 # define CLEARBIT(t, b) (t[(b) >> 3] &= (0xFF & ~(ONE << ((b) & 7))))
289 #define WITHIN_ARENA(p) \
290 ((char*)(p) >= sh.arena && (char*)(p) < &sh.arena[sh.arena_size])
291 #define WITHIN_FREELIST(p) \
292 ((char*)(p) >= (char*)sh.freelist && (char*)(p) < (char*)&sh.freelist[sh.freelist_size])
295 typedef struct sh_list_st
297 struct sh_list_st
*next
;
298 struct sh_list_st
**p_next
;
308 ossl_ssize_t freelist_size
;
310 unsigned char *bittable
;
311 unsigned char *bitmalloc
;
312 size_t bittable_size
; /* size in bits */
317 static size_t sh_getlist(char *ptr
)
319 ossl_ssize_t list
= sh
.freelist_size
- 1;
320 size_t bit
= (sh
.arena_size
+ ptr
- sh
.arena
) / sh
.minsize
;
322 for (; bit
; bit
>>= 1, list
--) {
323 if (TESTBIT(sh
.bittable
, bit
))
325 OPENSSL_assert((bit
& 1) == 0);
332 static int sh_testbit(char *ptr
, int list
, unsigned char *table
)
336 OPENSSL_assert(list
>= 0 && list
< sh
.freelist_size
);
337 OPENSSL_assert(((ptr
- sh
.arena
) & ((sh
.arena_size
>> list
) - 1)) == 0);
338 bit
= (ONE
<< list
) + ((ptr
- sh
.arena
) / (sh
.arena_size
>> list
));
339 OPENSSL_assert(bit
> 0 && bit
< sh
.bittable_size
);
340 return TESTBIT(table
, bit
);
343 static void sh_clearbit(char *ptr
, int list
, unsigned char *table
)
347 OPENSSL_assert(list
>= 0 && list
< sh
.freelist_size
);
348 OPENSSL_assert(((ptr
- sh
.arena
) & ((sh
.arena_size
>> list
) - 1)) == 0);
349 bit
= (ONE
<< list
) + ((ptr
- sh
.arena
) / (sh
.arena_size
>> list
));
350 OPENSSL_assert(bit
> 0 && bit
< sh
.bittable_size
);
351 OPENSSL_assert(TESTBIT(table
, bit
));
352 CLEARBIT(table
, bit
);
355 static void sh_setbit(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 OPENSSL_assert(!TESTBIT(table
, bit
));
367 static void sh_add_to_list(char **list
, char *ptr
)
371 OPENSSL_assert(WITHIN_FREELIST(list
));
372 OPENSSL_assert(WITHIN_ARENA(ptr
));
374 temp
= (SH_LIST
*)ptr
;
375 temp
->next
= *(SH_LIST
**)list
;
376 OPENSSL_assert(temp
->next
== NULL
|| WITHIN_ARENA(temp
->next
));
377 temp
->p_next
= (SH_LIST
**)list
;
379 if (temp
->next
!= NULL
) {
380 OPENSSL_assert((char **)temp
->next
->p_next
== list
);
381 temp
->next
->p_next
= &(temp
->next
);
387 static void sh_remove_from_list(char *ptr
)
389 SH_LIST
*temp
, *temp2
;
391 temp
= (SH_LIST
*)ptr
;
392 if (temp
->next
!= NULL
)
393 temp
->next
->p_next
= temp
->p_next
;
394 *temp
->p_next
= temp
->next
;
395 if (temp
->next
== NULL
)
399 OPENSSL_assert(WITHIN_FREELIST(temp2
->p_next
) || WITHIN_ARENA(temp2
->p_next
));
403 static int sh_init(size_t size
, size_t minsize
)
411 SYSTEM_INFO systemInfo
;
414 memset(&sh
, 0, sizeof(sh
));
416 /* make sure size is a powers of 2 */
417 OPENSSL_assert(size
> 0);
418 OPENSSL_assert((size
& (size
- 1)) == 0);
419 if (size
== 0 || (size
& (size
- 1)) != 0)
422 if (minsize
<= sizeof(SH_LIST
)) {
423 OPENSSL_assert(sizeof(SH_LIST
) <= 65536);
425 * Compute the minimum possible allocation size.
426 * This must be a power of 2 and at least as large as the SH_LIST
429 minsize
= sizeof(SH_LIST
) - 1;
430 minsize
|= minsize
>> 1;
431 minsize
|= minsize
>> 2;
432 if (sizeof(SH_LIST
) > 16)
433 minsize
|= minsize
>> 4;
434 if (sizeof(SH_LIST
) > 256)
435 minsize
|= minsize
>> 8;
438 /* make sure minsize is a powers of 2 */
439 OPENSSL_assert((minsize
& (minsize
- 1)) == 0);
440 if ((minsize
& (minsize
- 1)) != 0)
444 sh
.arena_size
= size
;
445 sh
.minsize
= minsize
;
446 sh
.bittable_size
= (sh
.arena_size
/ sh
.minsize
) * 2;
448 /* Prevent allocations of size 0 later on */
449 if (sh
.bittable_size
>> 3 == 0)
452 sh
.freelist_size
= -1;
453 for (i
= sh
.bittable_size
; i
; i
>>= 1)
456 sh
.freelist
= OPENSSL_zalloc(sh
.freelist_size
* sizeof(char *));
457 OPENSSL_assert(sh
.freelist
!= NULL
);
458 if (sh
.freelist
== NULL
)
461 sh
.bittable
= OPENSSL_zalloc(sh
.bittable_size
>> 3);
462 OPENSSL_assert(sh
.bittable
!= NULL
);
463 if (sh
.bittable
== NULL
)
466 sh
.bitmalloc
= OPENSSL_zalloc(sh
.bittable_size
>> 3);
467 OPENSSL_assert(sh
.bitmalloc
!= NULL
);
468 if (sh
.bitmalloc
== NULL
)
471 /* Allocate space for heap, and two extra pages as guards */
472 #if defined(_SC_PAGE_SIZE) || defined (_SC_PAGESIZE)
474 # if defined(_SC_PAGE_SIZE)
475 long tmppgsize
= sysconf(_SC_PAGE_SIZE
);
477 long tmppgsize
= sysconf(_SC_PAGESIZE
);
482 pgsize
= (size_t)tmppgsize
;
484 #elif defined(_WIN32)
485 GetSystemInfo(&systemInfo
);
486 pgsize
= (size_t)systemInfo
.dwPageSize
;
490 sh
.map_size
= pgsize
+ sh
.arena_size
+ pgsize
;
494 sh
.map_result
= mmap(NULL
, sh
.map_size
,
495 PROT_READ
|PROT_WRITE
, MAP_ANON
|MAP_PRIVATE
|MAP_CONCEAL
, -1, 0);
500 sh
.map_result
= MAP_FAILED
;
501 if ((fd
= open("/dev/zero", O_RDWR
)) >= 0) {
502 sh
.map_result
= mmap(NULL
, sh
.map_size
,
503 PROT_READ
|PROT_WRITE
, MAP_PRIVATE
, fd
, 0);
508 if (sh
.map_result
== MAP_FAILED
)
511 sh
.map_result
= VirtualAlloc(NULL
, sh
.map_size
, MEM_COMMIT
| MEM_RESERVE
, PAGE_READWRITE
);
513 if (sh
.map_result
== NULL
)
517 sh
.arena
= (char *)(sh
.map_result
+ pgsize
);
518 sh_setbit(sh
.arena
, 0, sh
.bittable
);
519 sh_add_to_list(&sh
.freelist
[0], sh
.arena
);
521 /* Now try to add guard pages and lock into memory. */
525 /* Starting guard is already aligned from mmap. */
526 if (mprotect(sh
.map_result
, pgsize
, PROT_NONE
) < 0)
529 if (VirtualProtect(sh
.map_result
, pgsize
, PAGE_NOACCESS
, &flOldProtect
) == FALSE
)
533 /* Ending guard page - need to round up to page boundary */
534 aligned
= (pgsize
+ sh
.arena_size
+ (pgsize
- 1)) & ~(pgsize
- 1);
536 if (mprotect(sh
.map_result
+ aligned
, pgsize
, PROT_NONE
) < 0)
539 if (VirtualProtect(sh
.map_result
+ aligned
, pgsize
, PAGE_NOACCESS
, &flOldProtect
) == FALSE
)
543 #if defined(OPENSSL_SYS_LINUX) && defined(MLOCK_ONFAULT) && defined(SYS_mlock2)
544 if (syscall(SYS_mlock2
, sh
.arena
, sh
.arena_size
, MLOCK_ONFAULT
) < 0) {
545 if (errno
== ENOSYS
) {
546 if (mlock(sh
.arena
, sh
.arena_size
) < 0)
552 #elif defined(_WIN32)
553 if (VirtualLock(sh
.arena
, sh
.arena_size
) == FALSE
)
556 if (mlock(sh
.arena
, sh
.arena_size
) < 0)
560 if (madvise(sh
.arena
, sh
.arena_size
, MADV_DONTDUMP
) < 0)
571 static void sh_done(void)
573 OPENSSL_free(sh
.freelist
);
574 OPENSSL_free(sh
.bittable
);
575 OPENSSL_free(sh
.bitmalloc
);
577 if (sh
.map_result
!= MAP_FAILED
&& sh
.map_size
)
578 munmap(sh
.map_result
, sh
.map_size
);
580 if (sh
.map_result
!= NULL
&& sh
.map_size
)
581 VirtualFree(sh
.map_result
, 0, MEM_RELEASE
);
583 memset(&sh
, 0, sizeof(sh
));
586 static int sh_allocated(const char *ptr
)
588 return WITHIN_ARENA(ptr
) ? 1 : 0;
591 static char *sh_find_my_buddy(char *ptr
, int list
)
596 bit
= (ONE
<< list
) + (ptr
- sh
.arena
) / (sh
.arena_size
>> list
);
599 if (TESTBIT(sh
.bittable
, bit
) && !TESTBIT(sh
.bitmalloc
, bit
))
600 chunk
= sh
.arena
+ ((bit
& ((ONE
<< list
) - 1)) * (sh
.arena_size
>> list
));
605 static void *sh_malloc(size_t size
)
607 ossl_ssize_t list
, slist
;
611 if (size
> sh
.arena_size
)
614 list
= sh
.freelist_size
- 1;
615 for (i
= sh
.minsize
; i
< size
; i
<<= 1)
620 /* try to find a larger entry to split */
621 for (slist
= list
; slist
>= 0; slist
--)
622 if (sh
.freelist
[slist
] != NULL
)
627 /* split larger entry */
628 while (slist
!= list
) {
629 char *temp
= sh
.freelist
[slist
];
631 /* remove from bigger list */
632 OPENSSL_assert(!sh_testbit(temp
, slist
, sh
.bitmalloc
));
633 sh_clearbit(temp
, slist
, sh
.bittable
);
634 sh_remove_from_list(temp
);
635 OPENSSL_assert(temp
!= sh
.freelist
[slist
]);
637 /* done with bigger list */
640 /* add to smaller list */
641 OPENSSL_assert(!sh_testbit(temp
, slist
, sh
.bitmalloc
));
642 sh_setbit(temp
, slist
, sh
.bittable
);
643 sh_add_to_list(&sh
.freelist
[slist
], temp
);
644 OPENSSL_assert(sh
.freelist
[slist
] == temp
);
647 temp
+= sh
.arena_size
>> slist
;
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
);
653 OPENSSL_assert(temp
-(sh
.arena_size
>> slist
) == sh_find_my_buddy(temp
, slist
));
656 /* peel off memory to hand back */
657 chunk
= sh
.freelist
[list
];
658 OPENSSL_assert(sh_testbit(chunk
, list
, sh
.bittable
));
659 sh_setbit(chunk
, list
, sh
.bitmalloc
);
660 sh_remove_from_list(chunk
);
662 OPENSSL_assert(WITHIN_ARENA(chunk
));
664 /* zero the free list header as a precaution against information leakage */
665 memset(chunk
, 0, sizeof(SH_LIST
));
670 static void sh_free(void *ptr
)
677 OPENSSL_assert(WITHIN_ARENA(ptr
));
678 if (!WITHIN_ARENA(ptr
))
681 list
= sh_getlist(ptr
);
682 OPENSSL_assert(sh_testbit(ptr
, list
, sh
.bittable
));
683 sh_clearbit(ptr
, list
, sh
.bitmalloc
);
684 sh_add_to_list(&sh
.freelist
[list
], ptr
);
686 /* Try to coalesce two adjacent free areas. */
687 while ((buddy
= sh_find_my_buddy(ptr
, list
)) != NULL
) {
688 OPENSSL_assert(ptr
== sh_find_my_buddy(buddy
, list
));
689 OPENSSL_assert(ptr
!= NULL
);
690 OPENSSL_assert(!sh_testbit(ptr
, list
, sh
.bitmalloc
));
691 sh_clearbit(ptr
, list
, sh
.bittable
);
692 sh_remove_from_list(ptr
);
693 OPENSSL_assert(!sh_testbit(ptr
, list
, sh
.bitmalloc
));
694 sh_clearbit(buddy
, list
, sh
.bittable
);
695 sh_remove_from_list(buddy
);
699 /* Zero the higher addressed block's free list pointers */
700 memset(ptr
> buddy
? ptr
: buddy
, 0, sizeof(SH_LIST
));
704 OPENSSL_assert(!sh_testbit(ptr
, list
, sh
.bitmalloc
));
705 sh_setbit(ptr
, list
, sh
.bittable
);
706 sh_add_to_list(&sh
.freelist
[list
], ptr
);
707 OPENSSL_assert(sh
.freelist
[list
] == ptr
);
711 static size_t sh_actual_size(char *ptr
)
715 OPENSSL_assert(WITHIN_ARENA(ptr
));
716 if (!WITHIN_ARENA(ptr
))
718 list
= sh_getlist(ptr
);
719 OPENSSL_assert(sh_testbit(ptr
, list
, sh
.bittable
));
720 return sh
.arena_size
/ (ONE
<< list
);
722 #endif /* OPENSSL_NO_SECURE_MEMORY */