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74924dcb RS |
1 | /* |
2 | * Copyright 2004-2014, Akamai Technologies. All Rights Reserved. | |
3 | * This file is distributed under the terms of the OpenSSL license. | |
4 | */ | |
5 | ||
6 | /* | |
7 | * This file is in two halves. The first half implements the public API | |
8 | * to be used by external consumers, and to be used by OpenSSL to store | |
9 | * data in a "secure arena." The second half implements the secure arena. | |
10 | * For details on that implementation, see below (look for uppercase | |
11 | * "SECURE HEAP IMPLEMENTATION"). | |
12 | */ | |
13 | #include <openssl/crypto.h> | |
14 | #include <e_os.h> | |
74924dcb RS |
15 | |
16 | #if defined(OPENSSL_SYS_LINUX) || defined(OPENSSL_SYS_UNIX) | |
17 | # define IMPLEMENTED | |
d4dfb0ba RS |
18 | # include <stdlib.h> |
19 | # include <string.h> | |
20 | # include <assert.h> | |
21 | # include <unistd.h> | |
74924dcb RS |
22 | # include <sys/mman.h> |
23 | # include <sys/param.h> | |
24 | #endif | |
25 | ||
26 | #define LOCK() CRYPTO_w_lock(CRYPTO_LOCK_MALLOC) | |
27 | #define UNLOCK() CRYPTO_w_unlock(CRYPTO_LOCK_MALLOC) | |
28 | #define CLEAR(p, s) OPENSSL_cleanse(p, s) | |
34750dc2 BL |
29 | #ifndef PAGE_SIZE |
30 | # define PAGE_SIZE 4096 | |
31 | #endif | |
74924dcb RS |
32 | |
33 | #ifdef IMPLEMENTED | |
34 | size_t secure_mem_used; | |
35 | ||
36 | static int secure_mem_initialized; | |
37 | static int too_late; | |
38 | ||
39 | /* | |
40 | * These are the functions that must be implemented by a secure heap (sh). | |
41 | */ | |
42 | static int sh_init(size_t size, int minsize); | |
43 | static char *sh_malloc(size_t size); | |
44 | static void sh_free(char *ptr); | |
45 | static void sh_done(void); | |
46 | static int sh_actual_size(char *ptr); | |
47 | static int sh_allocated(const char *ptr); | |
48 | #endif | |
49 | ||
50 | int CRYPTO_secure_malloc_init(size_t size, int minsize) | |
51 | { | |
52 | #ifdef IMPLEMENTED | |
53 | int ret = 0; | |
54 | ||
55 | if (too_late) | |
56 | return ret; | |
57 | LOCK(); | |
58 | OPENSSL_assert(!secure_mem_initialized); | |
59 | if (!secure_mem_initialized) { | |
60 | ret = sh_init(size, minsize); | |
61 | secure_mem_initialized = 1; | |
62 | } | |
63 | UNLOCK(); | |
64 | return ret; | |
65 | #else | |
66 | return 0; | |
67 | #endif /* IMPLEMENTED */ | |
68 | } | |
69 | ||
70 | void CRYPTO_secure_malloc_done() | |
71 | { | |
72 | #ifdef IMPLEMENTED | |
73 | LOCK(); | |
74 | sh_done(); | |
75 | secure_mem_initialized = 0; | |
76 | UNLOCK(); | |
77 | #endif /* IMPLEMENTED */ | |
78 | } | |
79 | ||
80 | int CRYPTO_secure_malloc_initialized() | |
81 | { | |
82 | #ifdef IMPLEMENTED | |
83 | return secure_mem_initialized; | |
84 | #else | |
85 | return 0; | |
86 | #endif /* IMPLEMENTED */ | |
87 | } | |
88 | ||
89 | void *CRYPTO_secure_malloc(int num, const char *file, int line) | |
90 | { | |
91 | #ifdef IMPLEMENTED | |
92 | void *ret; | |
93 | size_t actual_size; | |
94 | ||
95 | if (!secure_mem_initialized) { | |
96 | too_late = 1; | |
97 | return CRYPTO_malloc(num, file, line); | |
98 | } | |
99 | LOCK(); | |
100 | ret = sh_malloc(num); | |
101 | actual_size = ret ? sh_actual_size(ret) : 0; | |
102 | secure_mem_used += actual_size; | |
103 | UNLOCK(); | |
104 | return ret; | |
105 | #else | |
106 | return CRYPTO_malloc(num, file, line); | |
107 | #endif /* IMPLEMENTED */ | |
108 | } | |
109 | ||
110 | void CRYPTO_secure_free(void *ptr) | |
111 | { | |
112 | #ifdef IMPLEMENTED | |
113 | size_t actual_size; | |
114 | ||
115 | if (ptr == NULL) | |
116 | return; | |
117 | if (!secure_mem_initialized) { | |
118 | CRYPTO_free(ptr); | |
119 | return; | |
120 | } | |
121 | LOCK(); | |
122 | actual_size = sh_actual_size(ptr); | |
123 | CLEAR(ptr, actual_size); | |
124 | secure_mem_used -= actual_size; | |
125 | sh_free(ptr); | |
126 | UNLOCK(); | |
127 | #else | |
128 | CRYPTO_free(ptr); | |
129 | #endif /* IMPLEMENTED */ | |
130 | } | |
131 | ||
132 | int CRYPTO_secure_allocated(const void *ptr) | |
133 | { | |
134 | #ifdef IMPLEMENTED | |
135 | int ret; | |
136 | ||
137 | if (!secure_mem_initialized) | |
138 | return 0; | |
139 | LOCK(); | |
140 | ret = sh_allocated(ptr); | |
141 | UNLOCK(); | |
142 | return ret; | |
143 | #else | |
144 | return 0; | |
145 | #endif /* IMPLEMENTED */ | |
146 | } | |
147 | ||
148 | /* END OF PAGE ... | |
149 | ||
150 | ... START OF PAGE */ | |
151 | ||
152 | /* | |
153 | * SECURE HEAP IMPLEMENTATION | |
154 | */ | |
155 | #ifdef IMPLEMENTED | |
156 | ||
157 | ||
158 | /* | |
159 | * The implementation provided here uses a fixed-sized mmap() heap, | |
160 | * which is locked into memory, not written to core files, and protected | |
161 | * on either side by an unmapped page, which will catch pointer overruns | |
162 | * (or underruns) and an attempt to read data out of the secure heap. | |
163 | * Free'd memory is zero'd or otherwise cleansed. | |
164 | * | |
165 | * This is a pretty standard buddy allocator. We keep areas in a multiple | |
166 | * of "sh.minsize" units. The freelist and bitmaps are kept separately, | |
167 | * so all (and only) data is kept in the mmap'd heap. | |
168 | * | |
169 | * This code assumes eight-bit bytes. The numbers 3 and 7 are all over the | |
170 | * place. | |
171 | */ | |
172 | ||
173 | # define TESTBIT(t, b) (t[(b) >> 3] & (1 << ((b) & 7))) | |
174 | # define SETBIT(t, b) (t[(b) >> 3] |= (1 << ((b) & 7))) | |
175 | # define CLEARBIT(t, b) (t[(b) >> 3] &= (0xFF & ~(1 << ((b) & 7)))) | |
176 | ||
177 | #define WITHIN_ARENA(p) \ | |
178 | ((char*)(p) >= sh.arena && (char*)(p) < &sh.arena[sh.arena_size]) | |
179 | #define WITHIN_FREELIST(p) \ | |
180 | ((char*)(p) >= (char*)sh.freelist && (char*)(p) < (char*)&sh.freelist[sh.freelist_size]) | |
181 | ||
182 | ||
183 | typedef struct sh_list_st | |
184 | { | |
185 | struct sh_list_st *next; | |
186 | struct sh_list_st **p_next; | |
187 | } SH_LIST; | |
188 | ||
189 | typedef struct sh_st | |
190 | { | |
191 | char* map_result; | |
192 | size_t map_size; | |
193 | char *arena; | |
194 | int arena_size; | |
195 | char **freelist; | |
196 | int freelist_size; | |
197 | int minsize; | |
198 | unsigned char *bittable; | |
199 | unsigned char *bitmalloc; | |
200 | int bittable_size; /* size in bits */ | |
201 | } SH; | |
202 | ||
203 | static SH sh; | |
204 | ||
205 | static int sh_getlist(char *ptr) | |
206 | { | |
207 | int list = sh.freelist_size - 1; | |
208 | int bit = (sh.arena_size + ptr - sh.arena) / sh.minsize; | |
209 | ||
210 | for (; bit; bit >>= 1, list--) { | |
211 | if (TESTBIT(sh.bittable, bit)) | |
212 | break; | |
213 | OPENSSL_assert((bit & 1) == 0); | |
214 | } | |
215 | ||
216 | return list; | |
217 | } | |
218 | ||
219 | ||
220 | static int sh_testbit(char *ptr, int list, unsigned char *table) | |
221 | { | |
222 | int bit; | |
223 | ||
224 | OPENSSL_assert(list >= 0 && list < sh.freelist_size); | |
225 | OPENSSL_assert(((ptr - sh.arena) & ((sh.arena_size >> list) - 1)) == 0); | |
226 | bit = (1 << list) + ((ptr - sh.arena) / (sh.arena_size >> list)); | |
227 | OPENSSL_assert(bit > 0 && bit < sh.bittable_size); | |
228 | return TESTBIT(table, bit); | |
229 | } | |
230 | ||
231 | static void sh_clearbit(char *ptr, int list, unsigned char *table) | |
232 | { | |
233 | int bit; | |
234 | ||
235 | OPENSSL_assert(list >= 0 && list < sh.freelist_size); | |
236 | OPENSSL_assert(((ptr - sh.arena) & ((sh.arena_size >> list) - 1)) == 0); | |
237 | bit = (1 << list) + ((ptr - sh.arena) / (sh.arena_size >> list)); | |
238 | OPENSSL_assert(bit > 0 && bit < sh.bittable_size); | |
239 | OPENSSL_assert(TESTBIT(table, bit)); | |
240 | CLEARBIT(table, bit); | |
241 | } | |
242 | ||
243 | static void sh_setbit(char *ptr, int list, unsigned char *table) | |
244 | { | |
245 | int bit; | |
246 | ||
247 | OPENSSL_assert(list >= 0 && list < sh.freelist_size); | |
248 | OPENSSL_assert(((ptr - sh.arena) & ((sh.arena_size >> list) - 1)) == 0); | |
249 | bit = (1 << list) + ((ptr - sh.arena) / (sh.arena_size >> list)); | |
250 | OPENSSL_assert(bit > 0 && bit < sh.bittable_size); | |
251 | OPENSSL_assert(!TESTBIT(table, bit)); | |
252 | SETBIT(table, bit); | |
253 | } | |
254 | ||
255 | static void sh_add_to_list(char **list, char *ptr) | |
256 | { | |
257 | SH_LIST *temp; | |
258 | ||
259 | OPENSSL_assert(WITHIN_FREELIST(list)); | |
260 | OPENSSL_assert(WITHIN_ARENA(ptr)); | |
261 | ||
262 | temp = (SH_LIST *)ptr; | |
263 | temp->next = *(SH_LIST **)list; | |
264 | OPENSSL_assert(temp->next == NULL || WITHIN_ARENA(temp->next)); | |
265 | temp->p_next = (SH_LIST **)list; | |
266 | ||
267 | if (temp->next != NULL) { | |
268 | OPENSSL_assert((char **)temp->next->p_next == list); | |
269 | temp->next->p_next = &(temp->next); | |
270 | } | |
271 | ||
272 | *list = ptr; | |
273 | } | |
274 | ||
275 | static void sh_remove_from_list(char *ptr, char *list) | |
276 | { | |
277 | SH_LIST *temp, *temp2; | |
278 | ||
279 | temp = (SH_LIST *)ptr; | |
280 | if (temp->next != NULL) | |
281 | temp->next->p_next = temp->p_next; | |
282 | *temp->p_next = temp->next; | |
283 | if (temp->next == NULL) | |
284 | return; | |
285 | ||
286 | temp2 = temp->next; | |
287 | OPENSSL_assert(WITHIN_FREELIST(temp2->p_next) || WITHIN_ARENA(temp2->p_next)); | |
288 | } | |
289 | ||
290 | ||
291 | static int sh_init(size_t size, int minsize) | |
292 | { | |
293 | int i, ret; | |
294 | size_t pgsize; | |
295 | size_t aligned; | |
296 | ||
297 | memset(&sh, 0, sizeof sh); | |
298 | ||
299 | /* make sure size and minsize are powers of 2 */ | |
300 | OPENSSL_assert(size > 0); | |
301 | OPENSSL_assert((size & (size - 1)) == 0); | |
302 | OPENSSL_assert(minsize > 0); | |
303 | OPENSSL_assert((minsize & (minsize - 1)) == 0); | |
304 | if (size <= 0 || (size & (size - 1)) != 0) | |
305 | goto err; | |
306 | if (minsize <= 0 || (minsize & (minsize - 1)) != 0) | |
307 | goto err; | |
308 | ||
309 | sh.arena_size = size; | |
310 | sh.minsize = minsize; | |
311 | sh.bittable_size = (sh.arena_size / sh.minsize) * 2; | |
312 | ||
313 | sh.freelist_size = -1; | |
314 | for (i = sh.bittable_size; i; i >>= 1) | |
315 | sh.freelist_size++; | |
316 | ||
b51bce94 | 317 | sh.freelist = OPENSSL_zalloc(sh.freelist_size * sizeof (char *)); |
74924dcb RS |
318 | OPENSSL_assert(sh.freelist != NULL); |
319 | if (sh.freelist == NULL) | |
320 | goto err; | |
74924dcb | 321 | |
b51bce94 | 322 | sh.bittable = OPENSSL_zalloc(sh.bittable_size >> 3); |
74924dcb RS |
323 | OPENSSL_assert(sh.bittable != NULL); |
324 | if (sh.bittable == NULL) | |
325 | goto err; | |
74924dcb | 326 | |
b51bce94 | 327 | sh.bitmalloc = OPENSSL_zalloc(sh.bittable_size >> 3); |
74924dcb RS |
328 | OPENSSL_assert(sh.bitmalloc != NULL); |
329 | if (sh.bitmalloc == NULL) | |
330 | goto err; | |
74924dcb RS |
331 | |
332 | /* Allocate space for heap, and two extra pages as guards */ | |
333 | #ifdef _SC_PAGE_SIZE | |
334 | pgsize = (size_t)sysconf(_SC_PAGE_SIZE); | |
335 | #else | |
336 | pgsize = PAGE_SIZE; | |
337 | #endif | |
338 | sh.map_size = pgsize + sh.arena_size + pgsize; | |
339 | sh.map_result = mmap(NULL, sh.map_size, | |
340 | PROT_READ|PROT_WRITE, MAP_ANON|MAP_PRIVATE, -1, 0); | |
341 | OPENSSL_assert(sh.map_result != MAP_FAILED); | |
342 | if (sh.map_result == MAP_FAILED) | |
343 | goto err; | |
344 | sh.arena = (char *)(sh.map_result + pgsize); | |
345 | sh_setbit(sh.arena, 0, sh.bittable); | |
346 | sh_add_to_list(&sh.freelist[0], sh.arena); | |
347 | ||
348 | /* Now try to add guard pages and lock into memory. */ | |
349 | ret = 1; | |
350 | ||
351 | /* Starting guard is already aligned from mmap. */ | |
352 | if (mprotect(sh.map_result, pgsize, PROT_NONE) < 0) | |
353 | ret = 2; | |
354 | ||
355 | /* Ending guard page - need to round up to page boundary */ | |
356 | aligned = (pgsize + sh.arena_size + (pgsize - 1)) & ~(pgsize - 1); | |
357 | if (mprotect(sh.map_result + aligned, pgsize, PROT_NONE) < 0) | |
358 | ret = 2; | |
359 | ||
360 | if (mlock(sh.arena, sh.arena_size) < 0) | |
361 | ret = 2; | |
362 | #ifdef MADV_DONTDUMP | |
363 | if (madvise(sh.arena, sh.arena_size, MADV_DONTDUMP) < 0) | |
364 | ret = 2; | |
365 | #endif | |
366 | ||
367 | return ret; | |
368 | ||
369 | err: | |
370 | sh_done(); | |
371 | return 0; | |
372 | } | |
373 | ||
374 | static void sh_done() | |
375 | { | |
376 | OPENSSL_free(sh.freelist); | |
377 | OPENSSL_free(sh.bittable); | |
378 | OPENSSL_free(sh.bitmalloc); | |
379 | if (sh.map_result != NULL && sh.map_size) | |
380 | munmap(sh.map_result, sh.map_size); | |
381 | memset(&sh, 0, sizeof sh); | |
382 | } | |
383 | ||
384 | static int sh_allocated(const char *ptr) | |
385 | { | |
386 | return WITHIN_ARENA(ptr) ? 1 : 0; | |
387 | } | |
388 | ||
389 | static char *sh_find_my_buddy(char *ptr, int list) | |
390 | { | |
391 | int bit; | |
392 | char *chunk = NULL; | |
393 | ||
394 | bit = (1 << list) + (ptr - sh.arena) / (sh.arena_size >> list); | |
395 | bit ^= 1; | |
396 | ||
397 | if (TESTBIT(sh.bittable, bit) && !TESTBIT(sh.bitmalloc, bit)) | |
398 | chunk = sh.arena + ((bit & ((1 << list) - 1)) * (sh.arena_size >> list)); | |
399 | ||
400 | return chunk; | |
401 | } | |
402 | ||
403 | static char *sh_malloc(size_t size) | |
404 | { | |
405 | int list, slist; | |
406 | size_t i; | |
407 | char *chunk; | |
408 | ||
409 | list = sh.freelist_size - 1; | |
410 | for (i = sh.minsize; i < size; i <<= 1) | |
411 | list--; | |
412 | if (list < 0) | |
413 | return NULL; | |
414 | ||
415 | /* try to find a larger entry to split */ | |
416 | for (slist = list; slist >= 0; slist--) | |
417 | if (sh.freelist[slist] != NULL) | |
418 | break; | |
419 | if (slist < 0) | |
420 | return NULL; | |
421 | ||
422 | /* split larger entry */ | |
423 | while (slist != list) { | |
424 | char *temp = sh.freelist[slist]; | |
425 | ||
426 | /* remove from bigger list */ | |
427 | OPENSSL_assert(!sh_testbit(temp, slist, sh.bitmalloc)); | |
428 | sh_clearbit(temp, slist, sh.bittable); | |
429 | sh_remove_from_list(temp, sh.freelist[slist]); | |
430 | OPENSSL_assert(temp != sh.freelist[slist]); | |
431 | ||
432 | /* done with bigger list */ | |
433 | slist++; | |
434 | ||
435 | /* add to smaller list */ | |
436 | OPENSSL_assert(!sh_testbit(temp, slist, sh.bitmalloc)); | |
437 | sh_setbit(temp, slist, sh.bittable); | |
438 | sh_add_to_list(&sh.freelist[slist], temp); | |
439 | OPENSSL_assert(sh.freelist[slist] == temp); | |
440 | ||
441 | /* split in 2 */ | |
442 | temp += sh.arena_size >> slist; | |
443 | OPENSSL_assert(!sh_testbit(temp, slist, sh.bitmalloc)); | |
444 | sh_setbit(temp, slist, sh.bittable); | |
445 | sh_add_to_list(&sh.freelist[slist], temp); | |
446 | OPENSSL_assert(sh.freelist[slist] == temp); | |
447 | ||
448 | OPENSSL_assert(temp-(sh.arena_size >> slist) == sh_find_my_buddy(temp, slist)); | |
449 | } | |
450 | ||
451 | /* peel off memory to hand back */ | |
452 | chunk = sh.freelist[list]; | |
453 | OPENSSL_assert(sh_testbit(chunk, list, sh.bittable)); | |
454 | sh_setbit(chunk, list, sh.bitmalloc); | |
455 | sh_remove_from_list(chunk, sh.freelist[list]); | |
456 | ||
457 | OPENSSL_assert(WITHIN_ARENA(chunk)); | |
458 | ||
459 | return chunk; | |
460 | } | |
461 | ||
462 | static void sh_free(char *ptr) | |
463 | { | |
464 | int list; | |
465 | char *buddy; | |
466 | ||
467 | if (ptr == NULL) | |
468 | return; | |
469 | OPENSSL_assert(WITHIN_ARENA(ptr)); | |
470 | if (!WITHIN_ARENA(ptr)) | |
471 | return; | |
472 | ||
473 | list = sh_getlist(ptr); | |
474 | OPENSSL_assert(sh_testbit(ptr, list, sh.bittable)); | |
475 | sh_clearbit(ptr, list, sh.bitmalloc); | |
476 | sh_add_to_list(&sh.freelist[list], ptr); | |
477 | ||
478 | /* Try to coalesce two adjacent free areas. */ | |
479 | while ((buddy = sh_find_my_buddy(ptr, list)) != NULL) { | |
480 | OPENSSL_assert(ptr == sh_find_my_buddy(buddy, list)); | |
481 | OPENSSL_assert(ptr != NULL); | |
482 | OPENSSL_assert(!sh_testbit(ptr, list, sh.bitmalloc)); | |
483 | sh_clearbit(ptr, list, sh.bittable); | |
484 | sh_remove_from_list(ptr, sh.freelist[list]); | |
485 | OPENSSL_assert(!sh_testbit(ptr, list, sh.bitmalloc)); | |
486 | sh_clearbit(buddy, list, sh.bittable); | |
487 | sh_remove_from_list(buddy, sh.freelist[list]); | |
488 | ||
489 | list--; | |
490 | ||
491 | if (ptr > buddy) | |
492 | ptr = buddy; | |
493 | ||
494 | OPENSSL_assert(!sh_testbit(ptr, list, sh.bitmalloc)); | |
495 | sh_setbit(ptr, list, sh.bittable); | |
496 | sh_add_to_list(&sh.freelist[list], ptr); | |
497 | OPENSSL_assert(sh.freelist[list] == ptr); | |
498 | } | |
499 | } | |
500 | ||
501 | static int sh_actual_size(char *ptr) | |
502 | { | |
503 | int list; | |
504 | ||
505 | OPENSSL_assert(WITHIN_ARENA(ptr)); | |
506 | if (!WITHIN_ARENA(ptr)) | |
507 | return 0; | |
508 | list = sh_getlist(ptr); | |
509 | OPENSSL_assert(sh_testbit(ptr, list, sh.bittable)); | |
510 | return sh.arena_size / (1 << list); | |
511 | } | |
512 | #endif /* IMPLEMENTED */ |