1 /* 2 * Copyright 2015-2018 The OpenSSL Project Authors. All Rights Reserved. 3 * Copyright 2004-2014, Akamai Technologies. All Rights Reserved. 4 * 5 * Licensed under the OpenSSL license (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 9 */ 10 11 /* 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"). 17 */ 18 #include "e_os.h" 19 #include <openssl/crypto.h> 20 21 #include <string.h> 22 23 /* e_os.h defines OPENSSL_SECURE_MEMORY if secure memory can be implemented */ 24 #ifdef OPENSSL_SECURE_MEMORY 25 # include <stdlib.h> 26 # include <assert.h> 27 # include <unistd.h> 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> 34 # include <errno.h> 35 # endif 36 # endif 37 # include <sys/param.h> 38 # include <sys/stat.h> 39 # include <fcntl.h> 40 #endif 41 42 #define CLEAR(p, s) OPENSSL_cleanse(p, s) 43 #ifndef PAGE_SIZE 44 # define PAGE_SIZE 4096 45 #endif 46 #if !defined(MAP_ANON) && defined(MAP_ANONYMOUS) 47 # define MAP_ANON MAP_ANONYMOUS 48 #endif 49 50 #ifdef OPENSSL_SECURE_MEMORY 51 static size_t secure_mem_used; 52 53 static int secure_mem_initialized; 54 55 static CRYPTO_RWLOCK *sec_malloc_lock = NULL; 56 57 /* 58 * These are the functions that must be implemented by a secure heap (sh). 59 */ 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); 66 #endif 67 68 int CRYPTO_secure_malloc_init(size_t size, int minsize) 69 { 70 #ifdef OPENSSL_SECURE_MEMORY 71 int ret = 0; 72 73 if (!secure_mem_initialized) { 74 sec_malloc_lock = CRYPTO_THREAD_lock_new(); 75 if (sec_malloc_lock == NULL) 76 return 0; 77 if ((ret = sh_init(size, minsize)) != 0) { 78 secure_mem_initialized = 1; 79 } else { 80 CRYPTO_THREAD_lock_free(sec_malloc_lock); 81 sec_malloc_lock = NULL; 82 } 83 } 84 85 return ret; 86 #else 87 return 0; 88 #endif /* OPENSSL_SECURE_MEMORY */ 89 } 90 91 int CRYPTO_secure_malloc_done(void) 92 { 93 #ifdef OPENSSL_SECURE_MEMORY 94 if (secure_mem_used == 0) { 95 sh_done(); 96 secure_mem_initialized = 0; 97 CRYPTO_THREAD_lock_free(sec_malloc_lock); 98 sec_malloc_lock = NULL; 99 return 1; 100 } 101 #endif /* OPENSSL_SECURE_MEMORY */ 102 return 0; 103 } 104 105 int CRYPTO_secure_malloc_initialized(void) 106 { 107 #ifdef OPENSSL_SECURE_MEMORY 108 return secure_mem_initialized; 109 #else 110 return 0; 111 #endif /* OPENSSL_SECURE_MEMORY */ 112 } 113 114 void *CRYPTO_secure_malloc(size_t num, const char *file, int line) 115 { 116 #ifdef OPENSSL_SECURE_MEMORY 117 void *ret; 118 size_t actual_size; 119 120 if (!secure_mem_initialized) { 121 return CRYPTO_malloc(num, file, line); 122 } 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); 128 return ret; 129 #else 130 return CRYPTO_malloc(num, file, line); 131 #endif /* OPENSSL_SECURE_MEMORY */ 132 } 133 134 void *CRYPTO_secure_zalloc(size_t num, const char *file, int line) 135 { 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); 140 #endif 141 return CRYPTO_zalloc(num, file, line); 142 } 143 144 void CRYPTO_secure_free(void *ptr, const char *file, int line) 145 { 146 #ifdef OPENSSL_SECURE_MEMORY 147 size_t actual_size; 148 149 if (ptr == NULL) 150 return; 151 if (!CRYPTO_secure_allocated(ptr)) { 152 CRYPTO_free(ptr, file, line); 153 return; 154 } 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; 159 sh_free(ptr); 160 CRYPTO_THREAD_unlock(sec_malloc_lock); 161 #else 162 CRYPTO_free(ptr, file, line); 163 #endif /* OPENSSL_SECURE_MEMORY */ 164 } 165 166 void CRYPTO_secure_clear_free(void *ptr, size_t num, 167 const char *file, int line) 168 { 169 #ifdef OPENSSL_SECURE_MEMORY 170 size_t actual_size; 171 172 if (ptr == NULL) 173 return; 174 if (!CRYPTO_secure_allocated(ptr)) { 175 OPENSSL_cleanse(ptr, num); 176 CRYPTO_free(ptr, file, line); 177 return; 178 } 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; 183 sh_free(ptr); 184 CRYPTO_THREAD_unlock(sec_malloc_lock); 185 #else 186 if (ptr == NULL) 187 return; 188 OPENSSL_cleanse(ptr, num); 189 CRYPTO_free(ptr, file, line); 190 #endif /* OPENSSL_SECURE_MEMORY */ 191 } 192 193 int CRYPTO_secure_allocated(const void *ptr) 194 { 195 #ifdef OPENSSL_SECURE_MEMORY 196 int ret; 197 198 if (!secure_mem_initialized) 199 return 0; 200 CRYPTO_THREAD_write_lock(sec_malloc_lock); 201 ret = sh_allocated(ptr); 202 CRYPTO_THREAD_unlock(sec_malloc_lock); 203 return ret; 204 #else 205 return 0; 206 #endif /* OPENSSL_SECURE_MEMORY */ 207 } 208 209 size_t CRYPTO_secure_used(void) 210 { 211 #ifdef OPENSSL_SECURE_MEMORY 212 return secure_mem_used; 213 #else 214 return 0; 215 #endif /* OPENSSL_SECURE_MEMORY */ 216 } 217 218 size_t CRYPTO_secure_actual_size(void *ptr) 219 { 220 #ifdef OPENSSL_SECURE_MEMORY 221 size_t actual_size; 222 223 CRYPTO_THREAD_write_lock(sec_malloc_lock); 224 actual_size = sh_actual_size(ptr); 225 CRYPTO_THREAD_unlock(sec_malloc_lock); 226 return actual_size; 227 #else 228 return 0; 229 #endif 230 } 231 /* END OF PAGE ... 232 233 ... START OF PAGE */ 234 235 /* 236 * SECURE HEAP IMPLEMENTATION 237 */ 238 #ifdef OPENSSL_SECURE_MEMORY 239 240 241 /* 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. 247 * 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. 251 * 252 * This code assumes eight-bit bytes. The numbers 3 and 7 are all over the 253 * place. 254 */ 255 256 #define ONE ((size_t)1) 257 258 # 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)))) 261 262 #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]) 266 267 268 typedef struct sh_list_st 269 { 270 struct sh_list_st *next; 271 struct sh_list_st **p_next; 272 } SH_LIST; 273 274 typedef struct sh_st 275 { 276 char* map_result; 277 size_t map_size; 278 char *arena; 279 size_t arena_size; 280 char **freelist; 281 ossl_ssize_t freelist_size; 282 size_t minsize; 283 unsigned char *bittable; 284 unsigned char *bitmalloc; 285 size_t bittable_size; /* size in bits */ 286 } SH; 287 288 static SH sh; 289 290 static size_t sh_getlist(char *ptr) 291 { 292 ossl_ssize_t list = sh.freelist_size - 1; 293 size_t bit = (sh.arena_size + ptr - sh.arena) / sh.minsize; 294 295 for (; bit; bit >>= 1, list--) { 296 if (TESTBIT(sh.bittable, bit)) 297 break; 298 OPENSSL_assert((bit & 1) == 0); 299 } 300 301 return list; 302 } 303 304 305 static int sh_testbit(char *ptr, int list, unsigned char *table) 306 { 307 size_t bit; 308 309 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); 314 } 315 316 static void sh_clearbit(char *ptr, int list, unsigned char *table) 317 { 318 size_t bit; 319 320 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); 326 } 327 328 static void sh_setbit(char *ptr, int list, unsigned char *table) 329 { 330 size_t bit; 331 332 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)); 337 SETBIT(table, bit); 338 } 339 340 static void sh_add_to_list(char **list, char *ptr) 341 { 342 SH_LIST *temp; 343 344 OPENSSL_assert(WITHIN_FREELIST(list)); 345 OPENSSL_assert(WITHIN_ARENA(ptr)); 346 347 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; 351 352 if (temp->next != NULL) { 353 OPENSSL_assert((char **)temp->next->p_next == list); 354 temp->next->p_next = &(temp->next); 355 } 356 357 *list = ptr; 358 } 359 360 static void sh_remove_from_list(char *ptr) 361 { 362 SH_LIST *temp, *temp2; 363 364 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) 369 return; 370 371 temp2 = temp->next; 372 OPENSSL_assert(WITHIN_FREELIST(temp2->p_next) || WITHIN_ARENA(temp2->p_next)); 373 } 374 375 376 static int sh_init(size_t size, int minsize) 377 { 378 int ret; 379 size_t i; 380 size_t pgsize; 381 size_t aligned; 382 383 memset(&sh, 0, sizeof(sh)); 384 385 /* 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) 391 goto err; 392 if (minsize <= 0 || (minsize & (minsize - 1)) != 0) 393 goto err; 394 395 while (minsize < (int)sizeof(SH_LIST)) 396 minsize *= 2; 397 398 sh.arena_size = size; 399 sh.minsize = minsize; 400 sh.bittable_size = (sh.arena_size / sh.minsize) * 2; 401 402 /* Prevent allocations of size 0 later on */ 403 if (sh.bittable_size >> 3 == 0) 404 goto err; 405 406 sh.freelist_size = -1; 407 for (i = sh.bittable_size; i; i >>= 1) 408 sh.freelist_size++; 409 410 sh.freelist = OPENSSL_zalloc(sh.freelist_size * sizeof(char *)); 411 OPENSSL_assert(sh.freelist != NULL); 412 if (sh.freelist == NULL) 413 goto err; 414 415 sh.bittable = OPENSSL_zalloc(sh.bittable_size >> 3); 416 OPENSSL_assert(sh.bittable != NULL); 417 if (sh.bittable == NULL) 418 goto err; 419 420 sh.bitmalloc = OPENSSL_zalloc(sh.bittable_size >> 3); 421 OPENSSL_assert(sh.bitmalloc != NULL); 422 if (sh.bitmalloc == NULL) 423 goto err; 424 425 /* Allocate space for heap, and two extra pages as guards */ 426 #if defined(_SC_PAGE_SIZE) || defined (_SC_PAGESIZE) 427 { 428 # if defined(_SC_PAGE_SIZE) 429 long tmppgsize = sysconf(_SC_PAGE_SIZE); 430 # else 431 long tmppgsize = sysconf(_SC_PAGESIZE); 432 # endif 433 if (tmppgsize < 1) 434 pgsize = PAGE_SIZE; 435 else 436 pgsize = (size_t)tmppgsize; 437 } 438 #else 439 pgsize = PAGE_SIZE; 440 #endif 441 sh.map_size = pgsize + sh.arena_size + pgsize; 442 if (1) { 443 #ifdef MAP_ANON 444 sh.map_result = mmap(NULL, sh.map_size, 445 PROT_READ|PROT_WRITE, MAP_ANON|MAP_PRIVATE, -1, 0); 446 } else { 447 #endif 448 int fd; 449 450 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); 454 close(fd); 455 } 456 } 457 if (sh.map_result == MAP_FAILED) 458 goto err; 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); 462 463 /* Now try to add guard pages and lock into memory. */ 464 ret = 1; 465 466 /* Starting guard is already aligned from mmap. */ 467 if (mprotect(sh.map_result, pgsize, PROT_NONE) < 0) 468 ret = 2; 469 470 /* 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) 473 ret = 2; 474 475 #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) 479 ret = 2; 480 } else { 481 ret = 2; 482 } 483 } 484 #else 485 if (mlock(sh.arena, sh.arena_size) < 0) 486 ret = 2; 487 #endif 488 #ifdef MADV_DONTDUMP 489 if (madvise(sh.arena, sh.arena_size, MADV_DONTDUMP) < 0) 490 ret = 2; 491 #endif 492 493 return ret; 494 495 err: 496 sh_done(); 497 return 0; 498 } 499 500 static void sh_done(void) 501 { 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)); 508 } 509 510 static int sh_allocated(const char *ptr) 511 { 512 return WITHIN_ARENA(ptr) ? 1 : 0; 513 } 514 515 static char *sh_find_my_buddy(char *ptr, int list) 516 { 517 size_t bit; 518 char *chunk = NULL; 519 520 bit = (ONE << list) + (ptr - sh.arena) / (sh.arena_size >> list); 521 bit ^= 1; 522 523 if (TESTBIT(sh.bittable, bit) && !TESTBIT(sh.bitmalloc, bit)) 524 chunk = sh.arena + ((bit & ((ONE << list) - 1)) * (sh.arena_size >> list)); 525 526 return chunk; 527 } 528 529 static void *sh_malloc(size_t size) 530 { 531 ossl_ssize_t list, slist; 532 size_t i; 533 char *chunk; 534 535 if (size > sh.arena_size) 536 return NULL; 537 538 list = sh.freelist_size - 1; 539 for (i = sh.minsize; i < size; i <<= 1) 540 list--; 541 if (list < 0) 542 return NULL; 543 544 /* try to find a larger entry to split */ 545 for (slist = list; slist >= 0; slist--) 546 if (sh.freelist[slist] != NULL) 547 break; 548 if (slist < 0) 549 return NULL; 550 551 /* split larger entry */ 552 while (slist != list) { 553 char *temp = sh.freelist[slist]; 554 555 /* 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]); 560 561 /* done with bigger list */ 562 slist++; 563 564 /* 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); 569 570 /* split in 2 */ 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); 576 577 OPENSSL_assert(temp-(sh.arena_size >> slist) == sh_find_my_buddy(temp, slist)); 578 } 579 580 /* 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); 585 586 OPENSSL_assert(WITHIN_ARENA(chunk)); 587 588 /* zero the free list header as a precaution against information leakage */ 589 memset(chunk, 0, sizeof(SH_LIST)); 590 591 return chunk; 592 } 593 594 static void sh_free(void *ptr) 595 { 596 size_t list; 597 void *buddy; 598 599 if (ptr == NULL) 600 return; 601 OPENSSL_assert(WITHIN_ARENA(ptr)); 602 if (!WITHIN_ARENA(ptr)) 603 return; 604 605 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); 609 610 /* 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); 620 621 list--; 622 623 /* Zero the higher addressed block's free list pointers */ 624 memset(ptr > buddy ? ptr : buddy, 0, sizeof(SH_LIST)); 625 if (ptr > buddy) 626 ptr = buddy; 627 628 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); 632 } 633 } 634 635 static size_t sh_actual_size(char *ptr) 636 { 637 int list; 638 639 OPENSSL_assert(WITHIN_ARENA(ptr)); 640 if (!WITHIN_ARENA(ptr)) 641 return 0; 642 list = sh_getlist(ptr); 643 OPENSSL_assert(sh_testbit(ptr, list, sh.bittable)); 644 return sh.arena_size / (ONE << list); 645 } 646 #endif /* OPENSSL_SECURE_MEMORY */ 647