1 /* 2 * Copyright 2015-2020 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 # if defined(__FreeBSD__) 38 # define MADV_DONTDUMP MADV_NOCORE 39 # endif 40 # if !defined(MAP_CONCEAL) 41 # define MAP_CONCEAL 0 42 # endif 43 # include <sys/param.h> 44 # include <sys/stat.h> 45 # include <fcntl.h> 46 #endif 47 48 #define CLEAR(p, s) OPENSSL_cleanse(p, s) 49 #ifndef PAGE_SIZE 50 # define PAGE_SIZE 4096 51 #endif 52 #if !defined(MAP_ANON) && defined(MAP_ANONYMOUS) 53 # define MAP_ANON MAP_ANONYMOUS 54 #endif 55 56 #ifdef OPENSSL_SECURE_MEMORY 57 static size_t secure_mem_used; 58 59 static int secure_mem_initialized; 60 61 static CRYPTO_RWLOCK *sec_malloc_lock = NULL; 62 63 /* 64 * These are the functions that must be implemented by a secure heap (sh). 65 */ 66 static int sh_init(size_t size, int minsize); 67 static void *sh_malloc(size_t size); 68 static void sh_free(void *ptr); 69 static void sh_done(void); 70 static size_t sh_actual_size(char *ptr); 71 static int sh_allocated(const char *ptr); 72 #endif 73 74 int CRYPTO_secure_malloc_init(size_t size, int minsize) 75 { 76 #ifdef OPENSSL_SECURE_MEMORY 77 int ret = 0; 78 79 if (!secure_mem_initialized) { 80 sec_malloc_lock = CRYPTO_THREAD_lock_new(); 81 if (sec_malloc_lock == NULL) 82 return 0; 83 if ((ret = sh_init(size, minsize)) != 0) { 84 secure_mem_initialized = 1; 85 } else { 86 CRYPTO_THREAD_lock_free(sec_malloc_lock); 87 sec_malloc_lock = NULL; 88 } 89 } 90 91 return ret; 92 #else 93 return 0; 94 #endif /* OPENSSL_SECURE_MEMORY */ 95 } 96 97 int CRYPTO_secure_malloc_done(void) 98 { 99 #ifdef OPENSSL_SECURE_MEMORY 100 if (secure_mem_used == 0) { 101 sh_done(); 102 secure_mem_initialized = 0; 103 CRYPTO_THREAD_lock_free(sec_malloc_lock); 104 sec_malloc_lock = NULL; 105 return 1; 106 } 107 #endif /* OPENSSL_SECURE_MEMORY */ 108 return 0; 109 } 110 111 int CRYPTO_secure_malloc_initialized(void) 112 { 113 #ifdef OPENSSL_SECURE_MEMORY 114 return secure_mem_initialized; 115 #else 116 return 0; 117 #endif /* OPENSSL_SECURE_MEMORY */ 118 } 119 120 void *CRYPTO_secure_malloc(size_t num, const char *file, int line) 121 { 122 #ifdef OPENSSL_SECURE_MEMORY 123 void *ret; 124 size_t actual_size; 125 126 if (!secure_mem_initialized) { 127 return CRYPTO_malloc(num, file, line); 128 } 129 CRYPTO_THREAD_write_lock(sec_malloc_lock); 130 ret = sh_malloc(num); 131 actual_size = ret ? sh_actual_size(ret) : 0; 132 secure_mem_used += actual_size; 133 CRYPTO_THREAD_unlock(sec_malloc_lock); 134 return ret; 135 #else 136 return CRYPTO_malloc(num, file, line); 137 #endif /* OPENSSL_SECURE_MEMORY */ 138 } 139 140 void *CRYPTO_secure_zalloc(size_t num, const char *file, int line) 141 { 142 #ifdef OPENSSL_SECURE_MEMORY 143 if (secure_mem_initialized) 144 /* CRYPTO_secure_malloc() zeroes allocations when it is implemented */ 145 return CRYPTO_secure_malloc(num, file, line); 146 #endif 147 return CRYPTO_zalloc(num, file, line); 148 } 149 150 void CRYPTO_secure_free(void *ptr, const char *file, int line) 151 { 152 #ifdef OPENSSL_SECURE_MEMORY 153 size_t actual_size; 154 155 if (ptr == NULL) 156 return; 157 if (!CRYPTO_secure_allocated(ptr)) { 158 CRYPTO_free(ptr, file, line); 159 return; 160 } 161 CRYPTO_THREAD_write_lock(sec_malloc_lock); 162 actual_size = sh_actual_size(ptr); 163 CLEAR(ptr, actual_size); 164 secure_mem_used -= actual_size; 165 sh_free(ptr); 166 CRYPTO_THREAD_unlock(sec_malloc_lock); 167 #else 168 CRYPTO_free(ptr, file, line); 169 #endif /* OPENSSL_SECURE_MEMORY */ 170 } 171 172 void CRYPTO_secure_clear_free(void *ptr, size_t num, 173 const char *file, int line) 174 { 175 #ifdef OPENSSL_SECURE_MEMORY 176 size_t actual_size; 177 178 if (ptr == NULL) 179 return; 180 if (!CRYPTO_secure_allocated(ptr)) { 181 OPENSSL_cleanse(ptr, num); 182 CRYPTO_free(ptr, file, line); 183 return; 184 } 185 CRYPTO_THREAD_write_lock(sec_malloc_lock); 186 actual_size = sh_actual_size(ptr); 187 CLEAR(ptr, actual_size); 188 secure_mem_used -= actual_size; 189 sh_free(ptr); 190 CRYPTO_THREAD_unlock(sec_malloc_lock); 191 #else 192 if (ptr == NULL) 193 return; 194 OPENSSL_cleanse(ptr, num); 195 CRYPTO_free(ptr, file, line); 196 #endif /* OPENSSL_SECURE_MEMORY */ 197 } 198 199 int CRYPTO_secure_allocated(const void *ptr) 200 { 201 #ifdef OPENSSL_SECURE_MEMORY 202 int ret; 203 204 if (!secure_mem_initialized) 205 return 0; 206 CRYPTO_THREAD_write_lock(sec_malloc_lock); 207 ret = sh_allocated(ptr); 208 CRYPTO_THREAD_unlock(sec_malloc_lock); 209 return ret; 210 #else 211 return 0; 212 #endif /* OPENSSL_SECURE_MEMORY */ 213 } 214 215 size_t CRYPTO_secure_used(void) 216 { 217 #ifdef OPENSSL_SECURE_MEMORY 218 return secure_mem_used; 219 #else 220 return 0; 221 #endif /* OPENSSL_SECURE_MEMORY */ 222 } 223 224 size_t CRYPTO_secure_actual_size(void *ptr) 225 { 226 #ifdef OPENSSL_SECURE_MEMORY 227 size_t actual_size; 228 229 CRYPTO_THREAD_write_lock(sec_malloc_lock); 230 actual_size = sh_actual_size(ptr); 231 CRYPTO_THREAD_unlock(sec_malloc_lock); 232 return actual_size; 233 #else 234 return 0; 235 #endif 236 } 237 /* END OF PAGE ... 238 239 ... START OF PAGE */ 240 241 /* 242 * SECURE HEAP IMPLEMENTATION 243 */ 244 #ifdef OPENSSL_SECURE_MEMORY 245 246 247 /* 248 * The implementation provided here uses a fixed-sized mmap() heap, 249 * which is locked into memory, not written to core files, and protected 250 * on either side by an unmapped page, which will catch pointer overruns 251 * (or underruns) and an attempt to read data out of the secure heap. 252 * Free'd memory is zero'd or otherwise cleansed. 253 * 254 * This is a pretty standard buddy allocator. We keep areas in a multiple 255 * of "sh.minsize" units. The freelist and bitmaps are kept separately, 256 * so all (and only) data is kept in the mmap'd heap. 257 * 258 * This code assumes eight-bit bytes. The numbers 3 and 7 are all over the 259 * place. 260 */ 261 262 #define ONE ((size_t)1) 263 264 # define TESTBIT(t, b) (t[(b) >> 3] & (ONE << ((b) & 7))) 265 # define SETBIT(t, b) (t[(b) >> 3] |= (ONE << ((b) & 7))) 266 # define CLEARBIT(t, b) (t[(b) >> 3] &= (0xFF & ~(ONE << ((b) & 7)))) 267 268 #define WITHIN_ARENA(p) \ 269 ((char*)(p) >= sh.arena && (char*)(p) < &sh.arena[sh.arena_size]) 270 #define WITHIN_FREELIST(p) \ 271 ((char*)(p) >= (char*)sh.freelist && (char*)(p) < (char*)&sh.freelist[sh.freelist_size]) 272 273 274 typedef struct sh_list_st 275 { 276 struct sh_list_st *next; 277 struct sh_list_st **p_next; 278 } SH_LIST; 279 280 typedef struct sh_st 281 { 282 char* map_result; 283 size_t map_size; 284 char *arena; 285 size_t arena_size; 286 char **freelist; 287 ossl_ssize_t freelist_size; 288 size_t minsize; 289 unsigned char *bittable; 290 unsigned char *bitmalloc; 291 size_t bittable_size; /* size in bits */ 292 } SH; 293 294 static SH sh; 295 296 static size_t sh_getlist(char *ptr) 297 { 298 ossl_ssize_t list = sh.freelist_size - 1; 299 size_t bit = (sh.arena_size + ptr - sh.arena) / sh.minsize; 300 301 for (; bit; bit >>= 1, list--) { 302 if (TESTBIT(sh.bittable, bit)) 303 break; 304 OPENSSL_assert((bit & 1) == 0); 305 } 306 307 return list; 308 } 309 310 311 static int sh_testbit(char *ptr, int list, unsigned char *table) 312 { 313 size_t bit; 314 315 OPENSSL_assert(list >= 0 && list < sh.freelist_size); 316 OPENSSL_assert(((ptr - sh.arena) & ((sh.arena_size >> list) - 1)) == 0); 317 bit = (ONE << list) + ((ptr - sh.arena) / (sh.arena_size >> list)); 318 OPENSSL_assert(bit > 0 && bit < sh.bittable_size); 319 return TESTBIT(table, bit); 320 } 321 322 static void sh_clearbit(char *ptr, int list, unsigned char *table) 323 { 324 size_t bit; 325 326 OPENSSL_assert(list >= 0 && list < sh.freelist_size); 327 OPENSSL_assert(((ptr - sh.arena) & ((sh.arena_size >> list) - 1)) == 0); 328 bit = (ONE << list) + ((ptr - sh.arena) / (sh.arena_size >> list)); 329 OPENSSL_assert(bit > 0 && bit < sh.bittable_size); 330 OPENSSL_assert(TESTBIT(table, bit)); 331 CLEARBIT(table, bit); 332 } 333 334 static void sh_setbit(char *ptr, int list, unsigned char *table) 335 { 336 size_t bit; 337 338 OPENSSL_assert(list >= 0 && list < sh.freelist_size); 339 OPENSSL_assert(((ptr - sh.arena) & ((sh.arena_size >> list) - 1)) == 0); 340 bit = (ONE << list) + ((ptr - sh.arena) / (sh.arena_size >> list)); 341 OPENSSL_assert(bit > 0 && bit < sh.bittable_size); 342 OPENSSL_assert(!TESTBIT(table, bit)); 343 SETBIT(table, bit); 344 } 345 346 static void sh_add_to_list(char **list, char *ptr) 347 { 348 SH_LIST *temp; 349 350 OPENSSL_assert(WITHIN_FREELIST(list)); 351 OPENSSL_assert(WITHIN_ARENA(ptr)); 352 353 temp = (SH_LIST *)ptr; 354 temp->next = *(SH_LIST **)list; 355 OPENSSL_assert(temp->next == NULL || WITHIN_ARENA(temp->next)); 356 temp->p_next = (SH_LIST **)list; 357 358 if (temp->next != NULL) { 359 OPENSSL_assert((char **)temp->next->p_next == list); 360 temp->next->p_next = &(temp->next); 361 } 362 363 *list = ptr; 364 } 365 366 static void sh_remove_from_list(char *ptr) 367 { 368 SH_LIST *temp, *temp2; 369 370 temp = (SH_LIST *)ptr; 371 if (temp->next != NULL) 372 temp->next->p_next = temp->p_next; 373 *temp->p_next = temp->next; 374 if (temp->next == NULL) 375 return; 376 377 temp2 = temp->next; 378 OPENSSL_assert(WITHIN_FREELIST(temp2->p_next) || WITHIN_ARENA(temp2->p_next)); 379 } 380 381 382 static int sh_init(size_t size, int minsize) 383 { 384 int ret; 385 size_t i; 386 size_t pgsize; 387 size_t aligned; 388 389 memset(&sh, 0, sizeof(sh)); 390 391 /* make sure size and minsize are powers of 2 */ 392 OPENSSL_assert(size > 0); 393 OPENSSL_assert((size & (size - 1)) == 0); 394 OPENSSL_assert(minsize > 0); 395 OPENSSL_assert((minsize & (minsize - 1)) == 0); 396 if (size <= 0 || (size & (size - 1)) != 0) 397 goto err; 398 if (minsize <= 0 || (minsize & (minsize - 1)) != 0) 399 goto err; 400 401 while (minsize < (int)sizeof(SH_LIST)) 402 minsize *= 2; 403 404 sh.arena_size = size; 405 sh.minsize = minsize; 406 sh.bittable_size = (sh.arena_size / sh.minsize) * 2; 407 408 /* Prevent allocations of size 0 later on */ 409 if (sh.bittable_size >> 3 == 0) 410 goto err; 411 412 sh.freelist_size = -1; 413 for (i = sh.bittable_size; i; i >>= 1) 414 sh.freelist_size++; 415 416 sh.freelist = OPENSSL_zalloc(sh.freelist_size * sizeof(char *)); 417 OPENSSL_assert(sh.freelist != NULL); 418 if (sh.freelist == NULL) 419 goto err; 420 421 sh.bittable = OPENSSL_zalloc(sh.bittable_size >> 3); 422 OPENSSL_assert(sh.bittable != NULL); 423 if (sh.bittable == NULL) 424 goto err; 425 426 sh.bitmalloc = OPENSSL_zalloc(sh.bittable_size >> 3); 427 OPENSSL_assert(sh.bitmalloc != NULL); 428 if (sh.bitmalloc == NULL) 429 goto err; 430 431 /* Allocate space for heap, and two extra pages as guards */ 432 #if defined(_SC_PAGE_SIZE) || defined (_SC_PAGESIZE) 433 { 434 # if defined(_SC_PAGE_SIZE) 435 long tmppgsize = sysconf(_SC_PAGE_SIZE); 436 # else 437 long tmppgsize = sysconf(_SC_PAGESIZE); 438 # endif 439 if (tmppgsize < 1) 440 pgsize = PAGE_SIZE; 441 else 442 pgsize = (size_t)tmppgsize; 443 } 444 #else 445 pgsize = PAGE_SIZE; 446 #endif 447 sh.map_size = pgsize + sh.arena_size + pgsize; 448 if (1) { 449 #ifdef MAP_ANON 450 sh.map_result = mmap(NULL, sh.map_size, 451 PROT_READ|PROT_WRITE, MAP_ANON|MAP_PRIVATE|MAP_CONCEAL, -1, 0); 452 } else { 453 #endif 454 int fd; 455 456 sh.map_result = MAP_FAILED; 457 if ((fd = open("/dev/zero", O_RDWR)) >= 0) { 458 sh.map_result = mmap(NULL, sh.map_size, 459 PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0); 460 close(fd); 461 } 462 } 463 if (sh.map_result == MAP_FAILED) 464 goto err; 465 sh.arena = (char *)(sh.map_result + pgsize); 466 sh_setbit(sh.arena, 0, sh.bittable); 467 sh_add_to_list(&sh.freelist[0], sh.arena); 468 469 /* Now try to add guard pages and lock into memory. */ 470 ret = 1; 471 472 /* Starting guard is already aligned from mmap. */ 473 if (mprotect(sh.map_result, pgsize, PROT_NONE) < 0) 474 ret = 2; 475 476 /* Ending guard page - need to round up to page boundary */ 477 aligned = (pgsize + sh.arena_size + (pgsize - 1)) & ~(pgsize - 1); 478 if (mprotect(sh.map_result + aligned, pgsize, PROT_NONE) < 0) 479 ret = 2; 480 481 #if defined(OPENSSL_SYS_LINUX) && defined(MLOCK_ONFAULT) && defined(SYS_mlock2) 482 if (syscall(SYS_mlock2, sh.arena, sh.arena_size, MLOCK_ONFAULT) < 0) { 483 if (errno == ENOSYS) { 484 if (mlock(sh.arena, sh.arena_size) < 0) 485 ret = 2; 486 } else { 487 ret = 2; 488 } 489 } 490 #else 491 if (mlock(sh.arena, sh.arena_size) < 0) 492 ret = 2; 493 #endif 494 #ifdef MADV_DONTDUMP 495 if (madvise(sh.arena, sh.arena_size, MADV_DONTDUMP) < 0) 496 ret = 2; 497 #endif 498 499 return ret; 500 501 err: 502 sh_done(); 503 return 0; 504 } 505 506 static void sh_done(void) 507 { 508 OPENSSL_free(sh.freelist); 509 OPENSSL_free(sh.bittable); 510 OPENSSL_free(sh.bitmalloc); 511 if (sh.map_result != MAP_FAILED && sh.map_size) 512 munmap(sh.map_result, sh.map_size); 513 memset(&sh, 0, sizeof(sh)); 514 } 515 516 static int sh_allocated(const char *ptr) 517 { 518 return WITHIN_ARENA(ptr) ? 1 : 0; 519 } 520 521 static char *sh_find_my_buddy(char *ptr, int list) 522 { 523 size_t bit; 524 char *chunk = NULL; 525 526 bit = (ONE << list) + (ptr - sh.arena) / (sh.arena_size >> list); 527 bit ^= 1; 528 529 if (TESTBIT(sh.bittable, bit) && !TESTBIT(sh.bitmalloc, bit)) 530 chunk = sh.arena + ((bit & ((ONE << list) - 1)) * (sh.arena_size >> list)); 531 532 return chunk; 533 } 534 535 static void *sh_malloc(size_t size) 536 { 537 ossl_ssize_t list, slist; 538 size_t i; 539 char *chunk; 540 541 if (size > sh.arena_size) 542 return NULL; 543 544 list = sh.freelist_size - 1; 545 for (i = sh.minsize; i < size; i <<= 1) 546 list--; 547 if (list < 0) 548 return NULL; 549 550 /* try to find a larger entry to split */ 551 for (slist = list; slist >= 0; slist--) 552 if (sh.freelist[slist] != NULL) 553 break; 554 if (slist < 0) 555 return NULL; 556 557 /* split larger entry */ 558 while (slist != list) { 559 char *temp = sh.freelist[slist]; 560 561 /* remove from bigger list */ 562 OPENSSL_assert(!sh_testbit(temp, slist, sh.bitmalloc)); 563 sh_clearbit(temp, slist, sh.bittable); 564 sh_remove_from_list(temp); 565 OPENSSL_assert(temp != sh.freelist[slist]); 566 567 /* done with bigger list */ 568 slist++; 569 570 /* add to smaller list */ 571 OPENSSL_assert(!sh_testbit(temp, slist, sh.bitmalloc)); 572 sh_setbit(temp, slist, sh.bittable); 573 sh_add_to_list(&sh.freelist[slist], temp); 574 OPENSSL_assert(sh.freelist[slist] == temp); 575 576 /* split in 2 */ 577 temp += sh.arena_size >> slist; 578 OPENSSL_assert(!sh_testbit(temp, slist, sh.bitmalloc)); 579 sh_setbit(temp, slist, sh.bittable); 580 sh_add_to_list(&sh.freelist[slist], temp); 581 OPENSSL_assert(sh.freelist[slist] == temp); 582 583 OPENSSL_assert(temp-(sh.arena_size >> slist) == sh_find_my_buddy(temp, slist)); 584 } 585 586 /* peel off memory to hand back */ 587 chunk = sh.freelist[list]; 588 OPENSSL_assert(sh_testbit(chunk, list, sh.bittable)); 589 sh_setbit(chunk, list, sh.bitmalloc); 590 sh_remove_from_list(chunk); 591 592 OPENSSL_assert(WITHIN_ARENA(chunk)); 593 594 /* zero the free list header as a precaution against information leakage */ 595 memset(chunk, 0, sizeof(SH_LIST)); 596 597 return chunk; 598 } 599 600 static void sh_free(void *ptr) 601 { 602 size_t list; 603 void *buddy; 604 605 if (ptr == NULL) 606 return; 607 OPENSSL_assert(WITHIN_ARENA(ptr)); 608 if (!WITHIN_ARENA(ptr)) 609 return; 610 611 list = sh_getlist(ptr); 612 OPENSSL_assert(sh_testbit(ptr, list, sh.bittable)); 613 sh_clearbit(ptr, list, sh.bitmalloc); 614 sh_add_to_list(&sh.freelist[list], ptr); 615 616 /* Try to coalesce two adjacent free areas. */ 617 while ((buddy = sh_find_my_buddy(ptr, list)) != NULL) { 618 OPENSSL_assert(ptr == sh_find_my_buddy(buddy, list)); 619 OPENSSL_assert(ptr != NULL); 620 OPENSSL_assert(!sh_testbit(ptr, list, sh.bitmalloc)); 621 sh_clearbit(ptr, list, sh.bittable); 622 sh_remove_from_list(ptr); 623 OPENSSL_assert(!sh_testbit(ptr, list, sh.bitmalloc)); 624 sh_clearbit(buddy, list, sh.bittable); 625 sh_remove_from_list(buddy); 626 627 list--; 628 629 /* Zero the higher addressed block's free list pointers */ 630 memset(ptr > buddy ? ptr : buddy, 0, sizeof(SH_LIST)); 631 if (ptr > buddy) 632 ptr = buddy; 633 634 OPENSSL_assert(!sh_testbit(ptr, list, sh.bitmalloc)); 635 sh_setbit(ptr, list, sh.bittable); 636 sh_add_to_list(&sh.freelist[list], ptr); 637 OPENSSL_assert(sh.freelist[list] == ptr); 638 } 639 } 640 641 static size_t sh_actual_size(char *ptr) 642 { 643 int list; 644 645 OPENSSL_assert(WITHIN_ARENA(ptr)); 646 if (!WITHIN_ARENA(ptr)) 647 return 0; 648 list = sh_getlist(ptr); 649 OPENSSL_assert(sh_testbit(ptr, list, sh.bittable)); 650 return sh.arena_size / (ONE << list); 651 } 652 #endif /* OPENSSL_SECURE_MEMORY */ 653