2 * Copyright 2015-2018 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").
19 #include <openssl/crypto.h>
23 /* e_os.h defines OPENSSL_SECURE_MEMORY if secure memory can be implemented */
24 #ifdef OPENSSL_SECURE_MEMORY
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>
36 # include <sys/param.h>
38 # include <sys/stat.h>
42 #define CLEAR(p, s) OPENSSL_cleanse(p, s)
44 # define PAGE_SIZE 4096
46 #if !defined(MAP_ANON) && defined(MAP_ANONYMOUS)
47 # define MAP_ANON MAP_ANONYMOUS
50 #ifdef OPENSSL_SECURE_MEMORY
51 static size_t secure_mem_used
;
53 static int secure_mem_initialized
;
55 static CRYPTO_RWLOCK
*sec_malloc_lock
= NULL
;
58 * These are the functions that must be implemented by a secure heap (sh).
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
);
68 int CRYPTO_secure_malloc_init(size_t size
, int minsize
)
70 #ifdef OPENSSL_SECURE_MEMORY
73 if (!secure_mem_initialized
) {
74 sec_malloc_lock
= CRYPTO_THREAD_lock_new();
75 if (sec_malloc_lock
== NULL
)
77 if ((ret
= sh_init(size
, minsize
)) != 0) {
78 secure_mem_initialized
= 1;
80 CRYPTO_THREAD_lock_free(sec_malloc_lock
);
81 sec_malloc_lock
= NULL
;
88 #endif /* OPENSSL_SECURE_MEMORY */
91 int CRYPTO_secure_malloc_done(void)
93 #ifdef OPENSSL_SECURE_MEMORY
94 if (secure_mem_used
== 0) {
96 secure_mem_initialized
= 0;
97 CRYPTO_THREAD_lock_free(sec_malloc_lock
);
98 sec_malloc_lock
= NULL
;
101 #endif /* OPENSSL_SECURE_MEMORY */
105 int CRYPTO_secure_malloc_initialized(void)
107 #ifdef OPENSSL_SECURE_MEMORY
108 return secure_mem_initialized
;
111 #endif /* OPENSSL_SECURE_MEMORY */
114 void *CRYPTO_secure_malloc(size_t num
, const char *file
, int line
)
116 #ifdef OPENSSL_SECURE_MEMORY
120 if (!secure_mem_initialized
) {
121 return CRYPTO_malloc(num
, file
, line
);
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
);
130 return CRYPTO_malloc(num
, file
, line
);
131 #endif /* OPENSSL_SECURE_MEMORY */
134 void *CRYPTO_secure_zalloc(size_t num
, const char *file
, int line
)
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
);
141 return CRYPTO_zalloc(num
, file
, line
);
144 void CRYPTO_secure_free(void *ptr
, const char *file
, int line
)
146 #ifdef OPENSSL_SECURE_MEMORY
151 if (!CRYPTO_secure_allocated(ptr
)) {
152 CRYPTO_free(ptr
, file
, line
);
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
;
160 CRYPTO_THREAD_unlock(sec_malloc_lock
);
162 CRYPTO_free(ptr
, file
, line
);
163 #endif /* OPENSSL_SECURE_MEMORY */
166 void CRYPTO_secure_clear_free(void *ptr
, size_t num
,
167 const char *file
, int line
)
169 #ifdef OPENSSL_SECURE_MEMORY
174 if (!CRYPTO_secure_allocated(ptr
)) {
175 OPENSSL_cleanse(ptr
, num
);
176 CRYPTO_free(ptr
, file
, line
);
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
;
184 CRYPTO_THREAD_unlock(sec_malloc_lock
);
188 OPENSSL_cleanse(ptr
, num
);
189 CRYPTO_free(ptr
, file
, line
);
190 #endif /* OPENSSL_SECURE_MEMORY */
193 int CRYPTO_secure_allocated(const void *ptr
)
195 #ifdef OPENSSL_SECURE_MEMORY
198 if (!secure_mem_initialized
)
200 CRYPTO_THREAD_write_lock(sec_malloc_lock
);
201 ret
= sh_allocated(ptr
);
202 CRYPTO_THREAD_unlock(sec_malloc_lock
);
206 #endif /* OPENSSL_SECURE_MEMORY */
209 size_t CRYPTO_secure_used(void)
211 #ifdef OPENSSL_SECURE_MEMORY
212 return secure_mem_used
;
215 #endif /* OPENSSL_SECURE_MEMORY */
218 size_t CRYPTO_secure_actual_size(void *ptr
)
220 #ifdef OPENSSL_SECURE_MEMORY
223 CRYPTO_THREAD_write_lock(sec_malloc_lock
);
224 actual_size
= sh_actual_size(ptr
);
225 CRYPTO_THREAD_unlock(sec_malloc_lock
);
236 * SECURE HEAP IMPLEMENTATION
238 #ifdef OPENSSL_SECURE_MEMORY
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.
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.
252 * This code assumes eight-bit bytes. The numbers 3 and 7 are all over the
256 #define ONE ((size_t)1)
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))))
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])
268 typedef struct sh_list_st
270 struct sh_list_st
*next
;
271 struct sh_list_st
**p_next
;
281 ossl_ssize_t freelist_size
;
283 unsigned char *bittable
;
284 unsigned char *bitmalloc
;
285 size_t bittable_size
; /* size in bits */
290 static size_t sh_getlist(char *ptr
)
292 ossl_ssize_t list
= sh
.freelist_size
- 1;
293 size_t bit
= (sh
.arena_size
+ ptr
- sh
.arena
) / sh
.minsize
;
295 for (; bit
; bit
>>= 1, list
--) {
296 if (TESTBIT(sh
.bittable
, bit
))
298 OPENSSL_assert((bit
& 1) == 0);
305 static int sh_testbit(char *ptr
, int list
, unsigned char *table
)
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
);
316 static void sh_clearbit(char *ptr
, int list
, unsigned char *table
)
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
);
328 static void sh_setbit(char *ptr
, int list
, unsigned char *table
)
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
));
340 static void sh_add_to_list(char **list
, char *ptr
)
344 OPENSSL_assert(WITHIN_FREELIST(list
));
345 OPENSSL_assert(WITHIN_ARENA(ptr
));
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
;
352 if (temp
->next
!= NULL
) {
353 OPENSSL_assert((char **)temp
->next
->p_next
== list
);
354 temp
->next
->p_next
= &(temp
->next
);
360 static void sh_remove_from_list(char *ptr
)
362 SH_LIST
*temp
, *temp2
;
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
)
372 OPENSSL_assert(WITHIN_FREELIST(temp2
->p_next
) || WITHIN_ARENA(temp2
->p_next
));
376 static int sh_init(size_t size
, int minsize
)
383 memset(&sh
, 0, sizeof(sh
));
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)
392 if (minsize
<= 0 || (minsize
& (minsize
- 1)) != 0)
395 while (minsize
< (int)sizeof(SH_LIST
))
398 sh
.arena_size
= size
;
399 sh
.minsize
= minsize
;
400 sh
.bittable_size
= (sh
.arena_size
/ sh
.minsize
) * 2;
402 /* Prevent allocations of size 0 later on */
403 if (sh
.bittable_size
>> 3 == 0)
406 sh
.freelist_size
= -1;
407 for (i
= sh
.bittable_size
; i
; i
>>= 1)
410 sh
.freelist
= OPENSSL_zalloc(sh
.freelist_size
* sizeof(char *));
411 OPENSSL_assert(sh
.freelist
!= NULL
);
412 if (sh
.freelist
== NULL
)
415 sh
.bittable
= OPENSSL_zalloc(sh
.bittable_size
>> 3);
416 OPENSSL_assert(sh
.bittable
!= NULL
);
417 if (sh
.bittable
== NULL
)
420 sh
.bitmalloc
= OPENSSL_zalloc(sh
.bittable_size
>> 3);
421 OPENSSL_assert(sh
.bitmalloc
!= NULL
);
422 if (sh
.bitmalloc
== NULL
)
425 /* Allocate space for heap, and two extra pages as guards */
426 #if defined(_SC_PAGE_SIZE) || defined (_SC_PAGESIZE)
428 # if defined(_SC_PAGE_SIZE)
429 long tmppgsize
= sysconf(_SC_PAGE_SIZE
);
431 long tmppgsize
= sysconf(_SC_PAGESIZE
);
436 pgsize
= (size_t)tmppgsize
;
441 sh
.map_size
= pgsize
+ sh
.arena_size
+ pgsize
;
444 sh
.map_result
= mmap(NULL
, sh
.map_size
,
445 PROT_READ
|PROT_WRITE
, MAP_ANON
|MAP_PRIVATE
, -1, 0);
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);
457 if (sh
.map_result
== MAP_FAILED
)
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
);
463 /* Now try to add guard pages and lock into memory. */
466 /* Starting guard is already aligned from mmap. */
467 if (mprotect(sh
.map_result
, pgsize
, PROT_NONE
) < 0)
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)
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)
485 if (mlock(sh
.arena
, sh
.arena_size
) < 0)
489 if (madvise(sh
.arena
, sh
.arena_size
, MADV_DONTDUMP
) < 0)
500 static void sh_done(void)
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
));
510 static int sh_allocated(const char *ptr
)
512 return WITHIN_ARENA(ptr
) ? 1 : 0;
515 static char *sh_find_my_buddy(char *ptr
, int list
)
520 bit
= (ONE
<< list
) + (ptr
- sh
.arena
) / (sh
.arena_size
>> list
);
523 if (TESTBIT(sh
.bittable
, bit
) && !TESTBIT(sh
.bitmalloc
, bit
))
524 chunk
= sh
.arena
+ ((bit
& ((ONE
<< list
) - 1)) * (sh
.arena_size
>> list
));
529 static void *sh_malloc(size_t size
)
531 ossl_ssize_t list
, slist
;
535 if (size
> sh
.arena_size
)
538 list
= sh
.freelist_size
- 1;
539 for (i
= sh
.minsize
; i
< size
; i
<<= 1)
544 /* try to find a larger entry to split */
545 for (slist
= list
; slist
>= 0; slist
--)
546 if (sh
.freelist
[slist
] != NULL
)
551 /* split larger entry */
552 while (slist
!= list
) {
553 char *temp
= sh
.freelist
[slist
];
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
]);
561 /* done with bigger list */
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
);
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
);
577 OPENSSL_assert(temp
-(sh
.arena_size
>> slist
) == sh_find_my_buddy(temp
, slist
));
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
);
586 OPENSSL_assert(WITHIN_ARENA(chunk
));
588 /* zero the free list header as a precaution against information leakage */
589 memset(chunk
, 0, sizeof(SH_LIST
));
594 static void sh_free(void *ptr
)
601 OPENSSL_assert(WITHIN_ARENA(ptr
));
602 if (!WITHIN_ARENA(ptr
))
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
);
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
);
623 /* Zero the higher addressed block's free list pointers */
624 memset(ptr
> buddy
? ptr
: buddy
, 0, sizeof(SH_LIST
));
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
);
635 static size_t sh_actual_size(char *ptr
)
639 OPENSSL_assert(WITHIN_ARENA(ptr
));
640 if (!WITHIN_ARENA(ptr
))
642 list
= sh_getlist(ptr
);
643 OPENSSL_assert(sh_testbit(ptr
, list
, sh
.bittable
));
644 return sh
.arena_size
/ (ONE
<< list
);
646 #endif /* OPENSSL_SECURE_MEMORY */