1 /* $NetBSD: subr_asan.c,v 1.10 2019/06/15 06:40:34 maxv Exp $ */ 2 3 /* 4 * Copyright (c) 2018 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Maxime Villard. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 * POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32 #include <sys/cdefs.h> 33 __KERNEL_RCSID(0, "$NetBSD: subr_asan.c,v 1.10 2019/06/15 06:40:34 maxv Exp $"); 34 35 #include <sys/param.h> 36 #include <sys/device.h> 37 #include <sys/kernel.h> 38 #include <sys/param.h> 39 #include <sys/conf.h> 40 #include <sys/systm.h> 41 #include <sys/types.h> 42 #include <sys/asan.h> 43 44 #include <uvm/uvm.h> 45 46 #ifdef KASAN_PANIC 47 #define REPORT panic 48 #else 49 #define REPORT printf 50 #endif 51 52 /* ASAN constants. Part of the compiler ABI. */ 53 #define KASAN_SHADOW_SCALE_SHIFT 3 54 #define KASAN_SHADOW_SCALE_SIZE (1UL << KASAN_SHADOW_SCALE_SHIFT) 55 #define KASAN_SHADOW_MASK (KASAN_SHADOW_SCALE_SIZE - 1) 56 57 /* The MD code. */ 58 #include <machine/asan.h> 59 60 /* ASAN ABI version. */ 61 #if defined(__clang__) && (__clang_major__ - 0 >= 6) 62 #define ASAN_ABI_VERSION 8 63 #elif __GNUC_PREREQ__(7, 1) && !defined(__clang__) 64 #define ASAN_ABI_VERSION 8 65 #elif __GNUC_PREREQ__(6, 1) && !defined(__clang__) 66 #define ASAN_ABI_VERSION 6 67 #else 68 #error "Unsupported compiler version" 69 #endif 70 71 #define __RET_ADDR (unsigned long)__builtin_return_address(0) 72 73 /* Global variable descriptor. Part of the compiler ABI. */ 74 struct __asan_global_source_location { 75 const char *filename; 76 int line_no; 77 int column_no; 78 }; 79 struct __asan_global { 80 const void *beg; /* address of the global variable */ 81 size_t size; /* size of the global variable */ 82 size_t size_with_redzone; /* size with the redzone */ 83 const void *name; /* name of the variable */ 84 const void *module_name; /* name of the module where the var is declared */ 85 unsigned long has_dynamic_init; /* the var has dyn initializer (c++) */ 86 struct __asan_global_source_location *location; 87 #if ASAN_ABI_VERSION >= 7 88 uintptr_t odr_indicator; /* the address of the ODR indicator symbol */ 89 #endif 90 }; 91 92 static bool kasan_enabled __read_mostly = false; 93 94 /* -------------------------------------------------------------------------- */ 95 96 void 97 kasan_shadow_map(void *addr, size_t size) 98 { 99 size_t sz, npages, i; 100 vaddr_t sva, eva; 101 102 KASSERT((vaddr_t)addr % KASAN_SHADOW_SCALE_SIZE == 0); 103 104 sz = roundup(size, KASAN_SHADOW_SCALE_SIZE) / KASAN_SHADOW_SCALE_SIZE; 105 106 sva = (vaddr_t)kasan_md_addr_to_shad(addr); 107 eva = (vaddr_t)kasan_md_addr_to_shad(addr) + sz; 108 109 sva = rounddown(sva, PAGE_SIZE); 110 eva = roundup(eva, PAGE_SIZE); 111 112 npages = (eva - sva) / PAGE_SIZE; 113 114 KASSERT(sva >= KASAN_MD_SHADOW_START && eva < KASAN_MD_SHADOW_END); 115 116 for (i = 0; i < npages; i++) { 117 kasan_md_shadow_map_page(sva + i * PAGE_SIZE); 118 } 119 } 120 121 static void 122 kasan_ctors(void) 123 { 124 extern uint64_t __CTOR_LIST__, __CTOR_END__; 125 size_t nentries, i; 126 uint64_t *ptr; 127 128 nentries = ((size_t)&__CTOR_END__ - (size_t)&__CTOR_LIST__) / 129 sizeof(uintptr_t); 130 131 ptr = &__CTOR_LIST__; 132 for (i = 0; i < nentries; i++) { 133 void (*func)(void); 134 135 func = (void *)(*ptr); 136 (*func)(); 137 138 ptr++; 139 } 140 } 141 142 void 143 kasan_early_init(void *stack) 144 { 145 kasan_md_early_init(stack); 146 } 147 148 void 149 kasan_init(void) 150 { 151 /* MD initialization. */ 152 kasan_md_init(); 153 154 /* Now officially enabled. */ 155 kasan_enabled = true; 156 157 /* Call the ASAN constructors. */ 158 kasan_ctors(); 159 } 160 161 static inline const char * 162 kasan_code_name(uint8_t code) 163 { 164 switch (code) { 165 case KASAN_GENERIC_REDZONE: 166 return "GenericRedZone"; 167 case KASAN_MALLOC_REDZONE: 168 return "MallocRedZone"; 169 case KASAN_KMEM_REDZONE: 170 return "KmemRedZone"; 171 case KASAN_POOL_REDZONE: 172 return "PoolRedZone"; 173 case KASAN_POOL_FREED: 174 return "PoolUseAfterFree"; 175 case 1 ... 7: 176 return "RedZonePartial"; 177 case KASAN_STACK_LEFT: 178 return "StackLeft"; 179 case KASAN_STACK_RIGHT: 180 return "StackRight"; 181 case KASAN_STACK_PARTIAL: 182 return "StackPartial"; 183 case KASAN_USE_AFTER_SCOPE: 184 return "UseAfterScope"; 185 default: 186 return "Unknown"; 187 } 188 } 189 190 static void 191 kasan_report(unsigned long addr, size_t size, bool write, unsigned long pc, 192 uint8_t code) 193 { 194 REPORT("ASan: Unauthorized Access In %p: Addr %p [%zu byte%s, %s," 195 " %s]\n", 196 (void *)pc, (void *)addr, size, (size > 1 ? "s" : ""), 197 (write ? "write" : "read"), kasan_code_name(code)); 198 kasan_md_unwind(); 199 } 200 201 static __always_inline void 202 kasan_shadow_1byte_markvalid(unsigned long addr) 203 { 204 int8_t *byte = kasan_md_addr_to_shad((void *)addr); 205 int8_t last = (addr & KASAN_SHADOW_MASK) + 1; 206 207 *byte = last; 208 } 209 210 static __always_inline void 211 kasan_shadow_Nbyte_markvalid(const void *addr, size_t size) 212 { 213 size_t i; 214 215 for (i = 0; i < size; i++) { 216 kasan_shadow_1byte_markvalid((unsigned long)addr+i); 217 } 218 } 219 220 static __always_inline void 221 kasan_shadow_Nbyte_fill(const void *addr, size_t size, uint8_t code) 222 { 223 void *shad; 224 225 if (__predict_false(size == 0)) 226 return; 227 if (__predict_false(kasan_md_unsupported((vaddr_t)addr))) 228 return; 229 230 KASSERT((vaddr_t)addr % KASAN_SHADOW_SCALE_SIZE == 0); 231 KASSERT(size % KASAN_SHADOW_SCALE_SIZE == 0); 232 233 shad = (void *)kasan_md_addr_to_shad(addr); 234 size = size >> KASAN_SHADOW_SCALE_SHIFT; 235 236 __builtin_memset(shad, code, size); 237 } 238 239 void 240 kasan_add_redzone(size_t *size) 241 { 242 *size = roundup(*size, KASAN_SHADOW_SCALE_SIZE); 243 *size += KASAN_SHADOW_SCALE_SIZE; 244 } 245 246 void 247 kasan_softint(struct lwp *l) 248 { 249 const void *stk = (const void *)uvm_lwp_getuarea(l); 250 251 kasan_shadow_Nbyte_fill(stk, USPACE, 0); 252 } 253 254 /* 255 * In an area of size 'sz_with_redz', mark the 'size' first bytes as valid, 256 * and the rest as invalid. There are generally two use cases: 257 * 258 * o kasan_mark(addr, origsize, size, code), with origsize < size. This marks 259 * the redzone at the end of the buffer as invalid. 260 * 261 * o kasan_mark(addr, size, size, 0). This marks the entire buffer as valid. 262 */ 263 void 264 kasan_mark(const void *addr, size_t size, size_t sz_with_redz, uint8_t code) 265 { 266 size_t i, n, redz; 267 int8_t *shad; 268 269 KASSERT((vaddr_t)addr % KASAN_SHADOW_SCALE_SIZE == 0); 270 redz = sz_with_redz - roundup(size, KASAN_SHADOW_SCALE_SIZE); 271 KASSERT(redz % KASAN_SHADOW_SCALE_SIZE == 0); 272 shad = kasan_md_addr_to_shad(addr); 273 274 /* Chunks of 8 bytes, valid. */ 275 n = size / KASAN_SHADOW_SCALE_SIZE; 276 for (i = 0; i < n; i++) { 277 *shad++ = 0; 278 } 279 280 /* Possibly one chunk, mid. */ 281 if ((size & KASAN_SHADOW_MASK) != 0) { 282 *shad++ = (size & KASAN_SHADOW_MASK); 283 } 284 285 /* Chunks of 8 bytes, invalid. */ 286 n = redz / KASAN_SHADOW_SCALE_SIZE; 287 for (i = 0; i < n; i++) { 288 *shad++ = code; 289 } 290 } 291 292 /* -------------------------------------------------------------------------- */ 293 294 #define ADDR_CROSSES_SCALE_BOUNDARY(addr, size) \ 295 (addr >> KASAN_SHADOW_SCALE_SHIFT) != \ 296 ((addr + size - 1) >> KASAN_SHADOW_SCALE_SHIFT) 297 298 static __always_inline bool 299 kasan_shadow_1byte_isvalid(unsigned long addr, uint8_t *code) 300 { 301 int8_t *byte = kasan_md_addr_to_shad((void *)addr); 302 int8_t last = (addr & KASAN_SHADOW_MASK) + 1; 303 304 if (__predict_true(*byte == 0 || last <= *byte)) { 305 return true; 306 } 307 *code = *byte; 308 return false; 309 } 310 311 static __always_inline bool 312 kasan_shadow_2byte_isvalid(unsigned long addr, uint8_t *code) 313 { 314 int8_t *byte, last; 315 316 if (ADDR_CROSSES_SCALE_BOUNDARY(addr, 2)) { 317 return (kasan_shadow_1byte_isvalid(addr, code) && 318 kasan_shadow_1byte_isvalid(addr+1, code)); 319 } 320 321 byte = kasan_md_addr_to_shad((void *)addr); 322 last = ((addr + 1) & KASAN_SHADOW_MASK) + 1; 323 324 if (__predict_true(*byte == 0 || last <= *byte)) { 325 return true; 326 } 327 *code = *byte; 328 return false; 329 } 330 331 static __always_inline bool 332 kasan_shadow_4byte_isvalid(unsigned long addr, uint8_t *code) 333 { 334 int8_t *byte, last; 335 336 if (ADDR_CROSSES_SCALE_BOUNDARY(addr, 4)) { 337 return (kasan_shadow_2byte_isvalid(addr, code) && 338 kasan_shadow_2byte_isvalid(addr+2, code)); 339 } 340 341 byte = kasan_md_addr_to_shad((void *)addr); 342 last = ((addr + 3) & KASAN_SHADOW_MASK) + 1; 343 344 if (__predict_true(*byte == 0 || last <= *byte)) { 345 return true; 346 } 347 *code = *byte; 348 return false; 349 } 350 351 static __always_inline bool 352 kasan_shadow_8byte_isvalid(unsigned long addr, uint8_t *code) 353 { 354 int8_t *byte, last; 355 356 if (ADDR_CROSSES_SCALE_BOUNDARY(addr, 8)) { 357 return (kasan_shadow_4byte_isvalid(addr, code) && 358 kasan_shadow_4byte_isvalid(addr+4, code)); 359 } 360 361 byte = kasan_md_addr_to_shad((void *)addr); 362 last = ((addr + 7) & KASAN_SHADOW_MASK) + 1; 363 364 if (__predict_true(*byte == 0 || last <= *byte)) { 365 return true; 366 } 367 *code = *byte; 368 return false; 369 } 370 371 static __always_inline bool 372 kasan_shadow_Nbyte_isvalid(unsigned long addr, size_t size, uint8_t *code) 373 { 374 size_t i; 375 376 for (i = 0; i < size; i++) { 377 if (!kasan_shadow_1byte_isvalid(addr+i, code)) 378 return false; 379 } 380 381 return true; 382 } 383 384 static __always_inline void 385 kasan_shadow_check(unsigned long addr, size_t size, bool write, 386 unsigned long retaddr) 387 { 388 uint8_t code; 389 bool valid; 390 391 if (__predict_false(!kasan_enabled)) 392 return; 393 if (__predict_false(size == 0)) 394 return; 395 if (__predict_false(kasan_md_unsupported(addr))) 396 return; 397 398 if (__builtin_constant_p(size)) { 399 switch (size) { 400 case 1: 401 valid = kasan_shadow_1byte_isvalid(addr, &code); 402 break; 403 case 2: 404 valid = kasan_shadow_2byte_isvalid(addr, &code); 405 break; 406 case 4: 407 valid = kasan_shadow_4byte_isvalid(addr, &code); 408 break; 409 case 8: 410 valid = kasan_shadow_8byte_isvalid(addr, &code); 411 break; 412 default: 413 valid = kasan_shadow_Nbyte_isvalid(addr, size, &code); 414 break; 415 } 416 } else { 417 valid = kasan_shadow_Nbyte_isvalid(addr, size, &code); 418 } 419 420 if (__predict_false(!valid)) { 421 kasan_report(addr, size, write, retaddr, code); 422 } 423 } 424 425 /* -------------------------------------------------------------------------- */ 426 427 void * 428 kasan_memcpy(void *dst, const void *src, size_t len) 429 { 430 kasan_shadow_check((unsigned long)src, len, false, __RET_ADDR); 431 kasan_shadow_check((unsigned long)dst, len, true, __RET_ADDR); 432 return __builtin_memcpy(dst, src, len); 433 } 434 435 int 436 kasan_memcmp(const void *b1, const void *b2, size_t len) 437 { 438 kasan_shadow_check((unsigned long)b1, len, false, __RET_ADDR); 439 kasan_shadow_check((unsigned long)b2, len, false, __RET_ADDR); 440 return __builtin_memcmp(b1, b2, len); 441 } 442 443 void * 444 kasan_memset(void *b, int c, size_t len) 445 { 446 kasan_shadow_check((unsigned long)b, len, true, __RET_ADDR); 447 return __builtin_memset(b, c, len); 448 } 449 450 char * 451 kasan_strcpy(char *dst, const char *src) 452 { 453 char *save = dst; 454 455 while (1) { 456 kasan_shadow_check((unsigned long)src, 1, false, __RET_ADDR); 457 kasan_shadow_check((unsigned long)dst, 1, true, __RET_ADDR); 458 *dst = *src; 459 if (*src == '\0') 460 break; 461 src++, dst++; 462 } 463 464 return save; 465 } 466 467 int 468 kasan_strcmp(const char *s1, const char *s2) 469 { 470 while (1) { 471 kasan_shadow_check((unsigned long)s1, 1, false, __RET_ADDR); 472 kasan_shadow_check((unsigned long)s2, 1, false, __RET_ADDR); 473 if (*s1 != *s2) 474 break; 475 if (*s1 == '\0') 476 return 0; 477 s1++, s2++; 478 } 479 480 return (*(const unsigned char *)s1 - *(const unsigned char *)s2); 481 } 482 483 size_t 484 kasan_strlen(const char *str) 485 { 486 const char *s; 487 488 s = str; 489 while (1) { 490 kasan_shadow_check((unsigned long)s, 1, false, __RET_ADDR); 491 if (*s == '\0') 492 break; 493 s++; 494 } 495 496 return (s - str); 497 } 498 499 #undef kcopy 500 #undef copystr 501 #undef copyinstr 502 #undef copyoutstr 503 #undef copyin 504 505 int kasan_kcopy(const void *, void *, size_t); 506 int kasan_copystr(const void *, void *, size_t, size_t *); 507 int kasan_copyinstr(const void *, void *, size_t, size_t *); 508 int kasan_copyoutstr(const void *, void *, size_t, size_t *); 509 int kasan_copyin(const void *, void *, size_t); 510 int kcopy(const void *, void *, size_t); 511 int copystr(const void *, void *, size_t, size_t *); 512 int copyinstr(const void *, void *, size_t, size_t *); 513 int copyoutstr(const void *, void *, size_t, size_t *); 514 int copyin(const void *, void *, size_t); 515 516 int 517 kasan_kcopy(const void *src, void *dst, size_t len) 518 { 519 kasan_shadow_check((unsigned long)src, len, false, __RET_ADDR); 520 kasan_shadow_check((unsigned long)dst, len, true, __RET_ADDR); 521 return kcopy(src, dst, len); 522 } 523 524 int 525 kasan_copystr(const void *kfaddr, void *kdaddr, size_t len, size_t *done) 526 { 527 kasan_shadow_check((unsigned long)kdaddr, len, true, __RET_ADDR); 528 return copystr(kfaddr, kdaddr, len, done); 529 } 530 531 int 532 kasan_copyin(const void *uaddr, void *kaddr, size_t len) 533 { 534 kasan_shadow_check((unsigned long)kaddr, len, true, __RET_ADDR); 535 return copyin(uaddr, kaddr, len); 536 } 537 538 int 539 kasan_copyinstr(const void *uaddr, void *kaddr, size_t len, size_t *done) 540 { 541 kasan_shadow_check((unsigned long)kaddr, len, true, __RET_ADDR); 542 return copyinstr(uaddr, kaddr, len, done); 543 } 544 545 int 546 kasan_copyoutstr(const void *kaddr, void *uaddr, size_t len, size_t *done) 547 { 548 kasan_shadow_check((unsigned long)kaddr, len, false, __RET_ADDR); 549 return copyoutstr(kaddr, uaddr, len, done); 550 } 551 552 /* -------------------------------------------------------------------------- */ 553 554 void __asan_register_globals(struct __asan_global *, size_t); 555 void __asan_unregister_globals(struct __asan_global *, size_t); 556 557 void 558 __asan_register_globals(struct __asan_global *globals, size_t n) 559 { 560 size_t i; 561 562 for (i = 0; i < n; i++) { 563 kasan_mark(globals[i].beg, globals[i].size, 564 globals[i].size_with_redzone, KASAN_GENERIC_REDZONE); 565 } 566 } 567 568 void 569 __asan_unregister_globals(struct __asan_global *globals, size_t n) 570 { 571 /* never called */ 572 } 573 574 #define ASAN_LOAD_STORE(size) \ 575 void __asan_load##size(unsigned long); \ 576 void __asan_load##size(unsigned long addr) \ 577 { \ 578 kasan_shadow_check(addr, size, false, __RET_ADDR);\ 579 } \ 580 void __asan_load##size##_noabort(unsigned long); \ 581 void __asan_load##size##_noabort(unsigned long addr) \ 582 { \ 583 kasan_shadow_check(addr, size, false, __RET_ADDR);\ 584 } \ 585 void __asan_store##size(unsigned long); \ 586 void __asan_store##size(unsigned long addr) \ 587 { \ 588 kasan_shadow_check(addr, size, true, __RET_ADDR);\ 589 } \ 590 void __asan_store##size##_noabort(unsigned long); \ 591 void __asan_store##size##_noabort(unsigned long addr) \ 592 { \ 593 kasan_shadow_check(addr, size, true, __RET_ADDR);\ 594 } 595 596 ASAN_LOAD_STORE(1); 597 ASAN_LOAD_STORE(2); 598 ASAN_LOAD_STORE(4); 599 ASAN_LOAD_STORE(8); 600 ASAN_LOAD_STORE(16); 601 602 void __asan_loadN(unsigned long, size_t); 603 void __asan_loadN_noabort(unsigned long, size_t); 604 void __asan_storeN(unsigned long, size_t); 605 void __asan_storeN_noabort(unsigned long, size_t); 606 void __asan_handle_no_return(void); 607 608 void 609 __asan_loadN(unsigned long addr, size_t size) 610 { 611 kasan_shadow_check(addr, size, false, __RET_ADDR); 612 } 613 614 void 615 __asan_loadN_noabort(unsigned long addr, size_t size) 616 { 617 kasan_shadow_check(addr, size, false, __RET_ADDR); 618 } 619 620 void 621 __asan_storeN(unsigned long addr, size_t size) 622 { 623 kasan_shadow_check(addr, size, true, __RET_ADDR); 624 } 625 626 void 627 __asan_storeN_noabort(unsigned long addr, size_t size) 628 { 629 kasan_shadow_check(addr, size, true, __RET_ADDR); 630 } 631 632 void 633 __asan_handle_no_return(void) 634 { 635 /* nothing */ 636 } 637 638 #define ASAN_SET_SHADOW(byte) \ 639 void __asan_set_shadow_##byte(void *, size_t); \ 640 void __asan_set_shadow_##byte(void *addr, size_t size) \ 641 { \ 642 __builtin_memset((void *)addr, 0x##byte, size); \ 643 } 644 645 ASAN_SET_SHADOW(00); 646 ASAN_SET_SHADOW(f1); 647 ASAN_SET_SHADOW(f2); 648 ASAN_SET_SHADOW(f3); 649 ASAN_SET_SHADOW(f5); 650 ASAN_SET_SHADOW(f8); 651 652 void __asan_poison_stack_memory(const void *, size_t); 653 void __asan_unpoison_stack_memory(const void *, size_t); 654 655 void __asan_poison_stack_memory(const void *addr, size_t size) 656 { 657 size = roundup(size, KASAN_SHADOW_SCALE_SIZE); 658 kasan_shadow_Nbyte_fill(addr, size, KASAN_USE_AFTER_SCOPE); 659 } 660 661 void __asan_unpoison_stack_memory(const void *addr, size_t size) 662 { 663 kasan_shadow_Nbyte_markvalid(addr, size); 664 } 665