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