1 //===-- dfsan.cc ----------------------------------------------------------===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 // 10 // This file is a part of DataFlowSanitizer. 11 // 12 // This file defines the custom functions listed in done_abilist.txt. 13 //===----------------------------------------------------------------------===// 14 15 #include "sanitizer_common/sanitizer_common.h" 16 #include "sanitizer_common/sanitizer_internal_defs.h" 17 #include "sanitizer_common/sanitizer_linux.h" 18 19 #include "dfsan/dfsan.h" 20 21 #include <arpa/inet.h> 22 #include <assert.h> 23 #include <ctype.h> 24 #include <dlfcn.h> 25 #include <link.h> 26 #include <poll.h> 27 #include <pthread.h> 28 #include <pwd.h> 29 #include <sched.h> 30 #include <signal.h> 31 #include <stdarg.h> 32 #include <stdint.h> 33 #include <stdio.h> 34 #include <stdlib.h> 35 #include <string.h> 36 #include <sys/resource.h> 37 #include <sys/select.h> 38 #include <sys/stat.h> 39 #include <sys/time.h> 40 #include <sys/types.h> 41 #include <time.h> 42 #include <unistd.h> 43 44 using namespace __dfsan; 45 46 #define CALL_WEAK_INTERCEPTOR_HOOK(f, ...) \ 47 do { \ 48 if (f) \ 49 f(__VA_ARGS__); \ 50 } while (false) 51 #define DECLARE_WEAK_INTERCEPTOR_HOOK(f, ...) \ 52 SANITIZER_INTERFACE_ATTRIBUTE SANITIZER_WEAK_ATTRIBUTE void f(__VA_ARGS__); 53 54 extern "C" { 55 SANITIZER_INTERFACE_ATTRIBUTE int 56 __dfsw_stat(const char *path, struct stat *buf, dfsan_label path_label, 57 dfsan_label buf_label, dfsan_label *ret_label) { 58 int ret = stat(path, buf); 59 if (ret == 0) 60 dfsan_set_label(0, buf, sizeof(struct stat)); 61 *ret_label = 0; 62 return ret; 63 } 64 65 SANITIZER_INTERFACE_ATTRIBUTE int __dfsw_fstat(int fd, struct stat *buf, 66 dfsan_label fd_label, 67 dfsan_label buf_label, 68 dfsan_label *ret_label) { 69 int ret = fstat(fd, buf); 70 if (ret == 0) 71 dfsan_set_label(0, buf, sizeof(struct stat)); 72 *ret_label = 0; 73 return ret; 74 } 75 76 SANITIZER_INTERFACE_ATTRIBUTE char *__dfsw_strchr(const char *s, int c, 77 dfsan_label s_label, 78 dfsan_label c_label, 79 dfsan_label *ret_label) { 80 for (size_t i = 0;; ++i) { 81 if (s[i] == c || s[i] == 0) { 82 if (flags().strict_data_dependencies) { 83 *ret_label = s_label; 84 } else { 85 *ret_label = dfsan_union(dfsan_read_label(s, i + 1), 86 dfsan_union(s_label, c_label)); 87 } 88 return s[i] == 0 ? nullptr : const_cast<char *>(s+i); 89 } 90 } 91 } 92 93 DECLARE_WEAK_INTERCEPTOR_HOOK(dfsan_weak_hook_memcmp, uptr caller_pc, 94 const void *s1, const void *s2, size_t n, 95 dfsan_label s1_label, dfsan_label s2_label, 96 dfsan_label n_label) 97 98 SANITIZER_INTERFACE_ATTRIBUTE int __dfsw_memcmp(const void *s1, const void *s2, 99 size_t n, dfsan_label s1_label, 100 dfsan_label s2_label, 101 dfsan_label n_label, 102 dfsan_label *ret_label) { 103 CALL_WEAK_INTERCEPTOR_HOOK(dfsan_weak_hook_memcmp, GET_CALLER_PC(), s1, s2, n, 104 s1_label, s2_label, n_label); 105 const char *cs1 = (const char *) s1, *cs2 = (const char *) s2; 106 for (size_t i = 0; i != n; ++i) { 107 if (cs1[i] != cs2[i]) { 108 if (flags().strict_data_dependencies) { 109 *ret_label = 0; 110 } else { 111 *ret_label = dfsan_union(dfsan_read_label(cs1, i + 1), 112 dfsan_read_label(cs2, i + 1)); 113 } 114 return cs1[i] - cs2[i]; 115 } 116 } 117 118 if (flags().strict_data_dependencies) { 119 *ret_label = 0; 120 } else { 121 *ret_label = dfsan_union(dfsan_read_label(cs1, n), 122 dfsan_read_label(cs2, n)); 123 } 124 return 0; 125 } 126 127 DECLARE_WEAK_INTERCEPTOR_HOOK(dfsan_weak_hook_strcmp, uptr caller_pc, 128 const char *s1, const char *s2, 129 dfsan_label s1_label, dfsan_label s2_label) 130 131 SANITIZER_INTERFACE_ATTRIBUTE int __dfsw_strcmp(const char *s1, const char *s2, 132 dfsan_label s1_label, 133 dfsan_label s2_label, 134 dfsan_label *ret_label) { 135 CALL_WEAK_INTERCEPTOR_HOOK(dfsan_weak_hook_strcmp, GET_CALLER_PC(), s1, s2, 136 s1_label, s2_label); 137 for (size_t i = 0;; ++i) { 138 if (s1[i] != s2[i] || s1[i] == 0 || s2[i] == 0) { 139 if (flags().strict_data_dependencies) { 140 *ret_label = 0; 141 } else { 142 *ret_label = dfsan_union(dfsan_read_label(s1, i + 1), 143 dfsan_read_label(s2, i + 1)); 144 } 145 return s1[i] - s2[i]; 146 } 147 } 148 return 0; 149 } 150 151 SANITIZER_INTERFACE_ATTRIBUTE int 152 __dfsw_strcasecmp(const char *s1, const char *s2, dfsan_label s1_label, 153 dfsan_label s2_label, dfsan_label *ret_label) { 154 for (size_t i = 0;; ++i) { 155 if (tolower(s1[i]) != tolower(s2[i]) || s1[i] == 0 || s2[i] == 0) { 156 if (flags().strict_data_dependencies) { 157 *ret_label = 0; 158 } else { 159 *ret_label = dfsan_union(dfsan_read_label(s1, i + 1), 160 dfsan_read_label(s2, i + 1)); 161 } 162 return s1[i] - s2[i]; 163 } 164 } 165 return 0; 166 } 167 168 DECLARE_WEAK_INTERCEPTOR_HOOK(dfsan_weak_hook_strncmp, uptr caller_pc, 169 const char *s1, const char *s2, size_t n, 170 dfsan_label s1_label, dfsan_label s2_label, 171 dfsan_label n_label) 172 173 SANITIZER_INTERFACE_ATTRIBUTE int __dfsw_strncmp(const char *s1, const char *s2, 174 size_t n, dfsan_label s1_label, 175 dfsan_label s2_label, 176 dfsan_label n_label, 177 dfsan_label *ret_label) { 178 if (n == 0) { 179 *ret_label = 0; 180 return 0; 181 } 182 183 CALL_WEAK_INTERCEPTOR_HOOK(dfsan_weak_hook_strncmp, GET_CALLER_PC(), s1, s2, 184 n, s1_label, s2_label, n_label); 185 186 for (size_t i = 0;; ++i) { 187 if (s1[i] != s2[i] || s1[i] == 0 || s2[i] == 0 || i == n - 1) { 188 if (flags().strict_data_dependencies) { 189 *ret_label = 0; 190 } else { 191 *ret_label = dfsan_union(dfsan_read_label(s1, i + 1), 192 dfsan_read_label(s2, i + 1)); 193 } 194 return s1[i] - s2[i]; 195 } 196 } 197 return 0; 198 } 199 200 SANITIZER_INTERFACE_ATTRIBUTE int 201 __dfsw_strncasecmp(const char *s1, const char *s2, size_t n, 202 dfsan_label s1_label, dfsan_label s2_label, 203 dfsan_label n_label, dfsan_label *ret_label) { 204 if (n == 0) { 205 *ret_label = 0; 206 return 0; 207 } 208 209 for (size_t i = 0;; ++i) { 210 if (tolower(s1[i]) != tolower(s2[i]) || s1[i] == 0 || s2[i] == 0 || 211 i == n - 1) { 212 if (flags().strict_data_dependencies) { 213 *ret_label = 0; 214 } else { 215 *ret_label = dfsan_union(dfsan_read_label(s1, i + 1), 216 dfsan_read_label(s2, i + 1)); 217 } 218 return s1[i] - s2[i]; 219 } 220 } 221 return 0; 222 } 223 224 SANITIZER_INTERFACE_ATTRIBUTE void *__dfsw_calloc(size_t nmemb, size_t size, 225 dfsan_label nmemb_label, 226 dfsan_label size_label, 227 dfsan_label *ret_label) { 228 void *p = calloc(nmemb, size); 229 dfsan_set_label(0, p, nmemb * size); 230 *ret_label = 0; 231 return p; 232 } 233 234 SANITIZER_INTERFACE_ATTRIBUTE size_t 235 __dfsw_strlen(const char *s, dfsan_label s_label, dfsan_label *ret_label) { 236 size_t ret = strlen(s); 237 if (flags().strict_data_dependencies) { 238 *ret_label = 0; 239 } else { 240 *ret_label = dfsan_read_label(s, ret + 1); 241 } 242 return ret; 243 } 244 245 246 static void *dfsan_memcpy(void *dest, const void *src, size_t n) { 247 dfsan_label *sdest = shadow_for(dest); 248 const dfsan_label *ssrc = shadow_for(src); 249 internal_memcpy((void *)sdest, (const void *)ssrc, n * sizeof(dfsan_label)); 250 return internal_memcpy(dest, src, n); 251 } 252 253 static void dfsan_memset(void *s, int c, dfsan_label c_label, size_t n) { 254 internal_memset(s, c, n); 255 dfsan_set_label(c_label, s, n); 256 } 257 258 SANITIZER_INTERFACE_ATTRIBUTE 259 void *__dfsw_memcpy(void *dest, const void *src, size_t n, 260 dfsan_label dest_label, dfsan_label src_label, 261 dfsan_label n_label, dfsan_label *ret_label) { 262 *ret_label = dest_label; 263 return dfsan_memcpy(dest, src, n); 264 } 265 266 SANITIZER_INTERFACE_ATTRIBUTE 267 void *__dfsw_memset(void *s, int c, size_t n, 268 dfsan_label s_label, dfsan_label c_label, 269 dfsan_label n_label, dfsan_label *ret_label) { 270 dfsan_memset(s, c, c_label, n); 271 *ret_label = s_label; 272 return s; 273 } 274 275 SANITIZER_INTERFACE_ATTRIBUTE char * 276 __dfsw_strdup(const char *s, dfsan_label s_label, dfsan_label *ret_label) { 277 size_t len = strlen(s); 278 void *p = malloc(len+1); 279 dfsan_memcpy(p, s, len+1); 280 *ret_label = 0; 281 return static_cast<char *>(p); 282 } 283 284 SANITIZER_INTERFACE_ATTRIBUTE char * 285 __dfsw_strncpy(char *s1, const char *s2, size_t n, dfsan_label s1_label, 286 dfsan_label s2_label, dfsan_label n_label, 287 dfsan_label *ret_label) { 288 size_t len = strlen(s2); 289 if (len < n) { 290 dfsan_memcpy(s1, s2, len+1); 291 dfsan_memset(s1+len+1, 0, 0, n-len-1); 292 } else { 293 dfsan_memcpy(s1, s2, n); 294 } 295 296 *ret_label = s1_label; 297 return s1; 298 } 299 300 SANITIZER_INTERFACE_ATTRIBUTE ssize_t 301 __dfsw_pread(int fd, void *buf, size_t count, off_t offset, 302 dfsan_label fd_label, dfsan_label buf_label, 303 dfsan_label count_label, dfsan_label offset_label, 304 dfsan_label *ret_label) { 305 ssize_t ret = pread(fd, buf, count, offset); 306 if (ret > 0) 307 dfsan_set_label(0, buf, ret); 308 *ret_label = 0; 309 return ret; 310 } 311 312 SANITIZER_INTERFACE_ATTRIBUTE ssize_t 313 __dfsw_read(int fd, void *buf, size_t count, 314 dfsan_label fd_label, dfsan_label buf_label, 315 dfsan_label count_label, 316 dfsan_label *ret_label) { 317 ssize_t ret = read(fd, buf, count); 318 if (ret > 0) 319 dfsan_set_label(0, buf, ret); 320 *ret_label = 0; 321 return ret; 322 } 323 324 SANITIZER_INTERFACE_ATTRIBUTE int __dfsw_clock_gettime(clockid_t clk_id, 325 struct timespec *tp, 326 dfsan_label clk_id_label, 327 dfsan_label tp_label, 328 dfsan_label *ret_label) { 329 int ret = clock_gettime(clk_id, tp); 330 if (ret == 0) 331 dfsan_set_label(0, tp, sizeof(struct timespec)); 332 *ret_label = 0; 333 return ret; 334 } 335 336 static void unpoison(const void *ptr, uptr size) { 337 dfsan_set_label(0, const_cast<void *>(ptr), size); 338 } 339 340 // dlopen() ultimately calls mmap() down inside the loader, which generally 341 // doesn't participate in dynamic symbol resolution. Therefore we won't 342 // intercept its calls to mmap, and we have to hook it here. 343 SANITIZER_INTERFACE_ATTRIBUTE void * 344 __dfsw_dlopen(const char *filename, int flag, dfsan_label filename_label, 345 dfsan_label flag_label, dfsan_label *ret_label) { 346 void *handle = dlopen(filename, flag); 347 link_map *map = GET_LINK_MAP_BY_DLOPEN_HANDLE(handle); 348 if (map) 349 ForEachMappedRegion(map, unpoison); 350 *ret_label = 0; 351 return handle; 352 } 353 354 struct pthread_create_info { 355 void *(*start_routine_trampoline)(void *, void *, dfsan_label, dfsan_label *); 356 void *start_routine; 357 void *arg; 358 }; 359 360 static void *pthread_create_cb(void *p) { 361 pthread_create_info pci(*(pthread_create_info *)p); 362 free(p); 363 dfsan_label ret_label; 364 return pci.start_routine_trampoline(pci.start_routine, pci.arg, 0, 365 &ret_label); 366 } 367 368 SANITIZER_INTERFACE_ATTRIBUTE int __dfsw_pthread_create( 369 pthread_t *thread, const pthread_attr_t *attr, 370 void *(*start_routine_trampoline)(void *, void *, dfsan_label, 371 dfsan_label *), 372 void *start_routine, void *arg, dfsan_label thread_label, 373 dfsan_label attr_label, dfsan_label start_routine_label, 374 dfsan_label arg_label, dfsan_label *ret_label) { 375 pthread_create_info *pci = 376 (pthread_create_info *)malloc(sizeof(pthread_create_info)); 377 pci->start_routine_trampoline = start_routine_trampoline; 378 pci->start_routine = start_routine; 379 pci->arg = arg; 380 int rv = pthread_create(thread, attr, pthread_create_cb, (void *)pci); 381 if (rv != 0) 382 free(pci); 383 *ret_label = 0; 384 return rv; 385 } 386 387 struct dl_iterate_phdr_info { 388 int (*callback_trampoline)(void *callback, struct dl_phdr_info *info, 389 size_t size, void *data, dfsan_label info_label, 390 dfsan_label size_label, dfsan_label data_label, 391 dfsan_label *ret_label); 392 void *callback; 393 void *data; 394 }; 395 396 int dl_iterate_phdr_cb(struct dl_phdr_info *info, size_t size, void *data) { 397 dl_iterate_phdr_info *dipi = (dl_iterate_phdr_info *)data; 398 dfsan_set_label(0, *info); 399 dfsan_set_label(0, const_cast<char *>(info->dlpi_name), 400 strlen(info->dlpi_name) + 1); 401 dfsan_set_label( 402 0, const_cast<char *>(reinterpret_cast<const char *>(info->dlpi_phdr)), 403 sizeof(*info->dlpi_phdr) * info->dlpi_phnum); 404 dfsan_label ret_label; 405 return dipi->callback_trampoline(dipi->callback, info, size, dipi->data, 0, 0, 406 0, &ret_label); 407 } 408 409 SANITIZER_INTERFACE_ATTRIBUTE int __dfsw_dl_iterate_phdr( 410 int (*callback_trampoline)(void *callback, struct dl_phdr_info *info, 411 size_t size, void *data, dfsan_label info_label, 412 dfsan_label size_label, dfsan_label data_label, 413 dfsan_label *ret_label), 414 void *callback, void *data, dfsan_label callback_label, 415 dfsan_label data_label, dfsan_label *ret_label) { 416 dl_iterate_phdr_info dipi = { callback_trampoline, callback, data }; 417 *ret_label = 0; 418 return dl_iterate_phdr(dl_iterate_phdr_cb, &dipi); 419 } 420 421 SANITIZER_INTERFACE_ATTRIBUTE 422 char *__dfsw_ctime_r(const time_t *timep, char *buf, dfsan_label timep_label, 423 dfsan_label buf_label, dfsan_label *ret_label) { 424 char *ret = ctime_r(timep, buf); 425 if (ret) { 426 dfsan_set_label(dfsan_read_label(timep, sizeof(time_t)), buf, 427 strlen(buf) + 1); 428 *ret_label = buf_label; 429 } else { 430 *ret_label = 0; 431 } 432 return ret; 433 } 434 435 SANITIZER_INTERFACE_ATTRIBUTE 436 char *__dfsw_fgets(char *s, int size, FILE *stream, dfsan_label s_label, 437 dfsan_label size_label, dfsan_label stream_label, 438 dfsan_label *ret_label) { 439 char *ret = fgets(s, size, stream); 440 if (ret) { 441 dfsan_set_label(0, ret, strlen(ret) + 1); 442 *ret_label = s_label; 443 } else { 444 *ret_label = 0; 445 } 446 return ret; 447 } 448 449 SANITIZER_INTERFACE_ATTRIBUTE 450 char *__dfsw_getcwd(char *buf, size_t size, dfsan_label buf_label, 451 dfsan_label size_label, dfsan_label *ret_label) { 452 char *ret = getcwd(buf, size); 453 if (ret) { 454 dfsan_set_label(0, ret, strlen(ret) + 1); 455 *ret_label = buf_label; 456 } else { 457 *ret_label = 0; 458 } 459 return ret; 460 } 461 462 SANITIZER_INTERFACE_ATTRIBUTE 463 char *__dfsw_get_current_dir_name(dfsan_label *ret_label) { 464 char *ret = get_current_dir_name(); 465 if (ret) { 466 dfsan_set_label(0, ret, strlen(ret) + 1); 467 } 468 *ret_label = 0; 469 return ret; 470 } 471 472 SANITIZER_INTERFACE_ATTRIBUTE 473 int __dfsw_gethostname(char *name, size_t len, dfsan_label name_label, 474 dfsan_label len_label, dfsan_label *ret_label) { 475 int ret = gethostname(name, len); 476 if (ret == 0) { 477 dfsan_set_label(0, name, strlen(name) + 1); 478 } 479 *ret_label = 0; 480 return ret; 481 } 482 483 SANITIZER_INTERFACE_ATTRIBUTE 484 int __dfsw_getrlimit(int resource, struct rlimit *rlim, 485 dfsan_label resource_label, dfsan_label rlim_label, 486 dfsan_label *ret_label) { 487 int ret = getrlimit(resource, rlim); 488 if (ret == 0) { 489 dfsan_set_label(0, rlim, sizeof(struct rlimit)); 490 } 491 *ret_label = 0; 492 return ret; 493 } 494 495 SANITIZER_INTERFACE_ATTRIBUTE 496 int __dfsw_getrusage(int who, struct rusage *usage, dfsan_label who_label, 497 dfsan_label usage_label, dfsan_label *ret_label) { 498 int ret = getrusage(who, usage); 499 if (ret == 0) { 500 dfsan_set_label(0, usage, sizeof(struct rusage)); 501 } 502 *ret_label = 0; 503 return ret; 504 } 505 506 SANITIZER_INTERFACE_ATTRIBUTE 507 char *__dfsw_strcpy(char *dest, const char *src, dfsan_label dst_label, 508 dfsan_label src_label, dfsan_label *ret_label) { 509 char *ret = strcpy(dest, src); 510 if (ret) { 511 internal_memcpy(shadow_for(dest), shadow_for(src), 512 sizeof(dfsan_label) * (strlen(src) + 1)); 513 } 514 *ret_label = dst_label; 515 return ret; 516 } 517 518 SANITIZER_INTERFACE_ATTRIBUTE 519 long int __dfsw_strtol(const char *nptr, char **endptr, int base, 520 dfsan_label nptr_label, dfsan_label endptr_label, 521 dfsan_label base_label, dfsan_label *ret_label) { 522 char *tmp_endptr; 523 long int ret = strtol(nptr, &tmp_endptr, base); 524 if (endptr) { 525 *endptr = tmp_endptr; 526 } 527 if (tmp_endptr > nptr) { 528 // If *tmp_endptr is '\0' include its label as well. 529 *ret_label = dfsan_union( 530 base_label, 531 dfsan_read_label(nptr, tmp_endptr - nptr + (*tmp_endptr ? 0 : 1))); 532 } else { 533 *ret_label = 0; 534 } 535 return ret; 536 } 537 538 SANITIZER_INTERFACE_ATTRIBUTE 539 double __dfsw_strtod(const char *nptr, char **endptr, 540 dfsan_label nptr_label, dfsan_label endptr_label, 541 dfsan_label *ret_label) { 542 char *tmp_endptr; 543 double ret = strtod(nptr, &tmp_endptr); 544 if (endptr) { 545 *endptr = tmp_endptr; 546 } 547 if (tmp_endptr > nptr) { 548 // If *tmp_endptr is '\0' include its label as well. 549 *ret_label = dfsan_read_label( 550 nptr, 551 tmp_endptr - nptr + (*tmp_endptr ? 0 : 1)); 552 } else { 553 *ret_label = 0; 554 } 555 return ret; 556 } 557 558 SANITIZER_INTERFACE_ATTRIBUTE 559 long long int __dfsw_strtoll(const char *nptr, char **endptr, int base, 560 dfsan_label nptr_label, dfsan_label endptr_label, 561 dfsan_label base_label, dfsan_label *ret_label) { 562 char *tmp_endptr; 563 long long int ret = strtoll(nptr, &tmp_endptr, base); 564 if (endptr) { 565 *endptr = tmp_endptr; 566 } 567 if (tmp_endptr > nptr) { 568 // If *tmp_endptr is '\0' include its label as well. 569 *ret_label = dfsan_union( 570 base_label, 571 dfsan_read_label(nptr, tmp_endptr - nptr + (*tmp_endptr ? 0 : 1))); 572 } else { 573 *ret_label = 0; 574 } 575 return ret; 576 } 577 578 SANITIZER_INTERFACE_ATTRIBUTE 579 unsigned long int __dfsw_strtoul(const char *nptr, char **endptr, int base, 580 dfsan_label nptr_label, dfsan_label endptr_label, 581 dfsan_label base_label, dfsan_label *ret_label) { 582 char *tmp_endptr; 583 unsigned long int ret = strtoul(nptr, &tmp_endptr, base); 584 if (endptr) { 585 *endptr = tmp_endptr; 586 } 587 if (tmp_endptr > nptr) { 588 // If *tmp_endptr is '\0' include its label as well. 589 *ret_label = dfsan_union( 590 base_label, 591 dfsan_read_label(nptr, tmp_endptr - nptr + (*tmp_endptr ? 0 : 1))); 592 } else { 593 *ret_label = 0; 594 } 595 return ret; 596 } 597 598 SANITIZER_INTERFACE_ATTRIBUTE 599 long long unsigned int __dfsw_strtoull(const char *nptr, char **endptr, 600 dfsan_label nptr_label, 601 int base, dfsan_label endptr_label, 602 dfsan_label base_label, 603 dfsan_label *ret_label) { 604 char *tmp_endptr; 605 long long unsigned int ret = strtoull(nptr, &tmp_endptr, base); 606 if (endptr) { 607 *endptr = tmp_endptr; 608 } 609 if (tmp_endptr > nptr) { 610 // If *tmp_endptr is '\0' include its label as well. 611 *ret_label = dfsan_union( 612 base_label, 613 dfsan_read_label(nptr, tmp_endptr - nptr + (*tmp_endptr ? 0 : 1))); 614 } else { 615 *ret_label = 0; 616 } 617 return ret; 618 } 619 620 SANITIZER_INTERFACE_ATTRIBUTE 621 time_t __dfsw_time(time_t *t, dfsan_label t_label, dfsan_label *ret_label) { 622 time_t ret = time(t); 623 if (ret != (time_t) -1 && t) { 624 dfsan_set_label(0, t, sizeof(time_t)); 625 } 626 *ret_label = 0; 627 return ret; 628 } 629 630 SANITIZER_INTERFACE_ATTRIBUTE 631 int __dfsw_inet_pton(int af, const char *src, void *dst, dfsan_label af_label, 632 dfsan_label src_label, dfsan_label dst_label, 633 dfsan_label *ret_label) { 634 int ret = inet_pton(af, src, dst); 635 if (ret == 1) { 636 dfsan_set_label(dfsan_read_label(src, strlen(src) + 1), dst, 637 af == AF_INET ? sizeof(struct in_addr) : sizeof(in6_addr)); 638 } 639 *ret_label = 0; 640 return ret; 641 } 642 643 SANITIZER_INTERFACE_ATTRIBUTE 644 struct tm *__dfsw_localtime_r(const time_t *timep, struct tm *result, 645 dfsan_label timep_label, dfsan_label result_label, 646 dfsan_label *ret_label) { 647 struct tm *ret = localtime_r(timep, result); 648 if (ret) { 649 dfsan_set_label(dfsan_read_label(timep, sizeof(time_t)), result, 650 sizeof(struct tm)); 651 *ret_label = result_label; 652 } else { 653 *ret_label = 0; 654 } 655 return ret; 656 } 657 658 SANITIZER_INTERFACE_ATTRIBUTE 659 int __dfsw_getpwuid_r(id_t uid, struct passwd *pwd, 660 char *buf, size_t buflen, struct passwd **result, 661 dfsan_label uid_label, dfsan_label pwd_label, 662 dfsan_label buf_label, dfsan_label buflen_label, 663 dfsan_label result_label, dfsan_label *ret_label) { 664 // Store the data in pwd, the strings referenced from pwd in buf, and the 665 // address of pwd in *result. On failure, NULL is stored in *result. 666 int ret = getpwuid_r(uid, pwd, buf, buflen, result); 667 if (ret == 0) { 668 dfsan_set_label(0, pwd, sizeof(struct passwd)); 669 dfsan_set_label(0, buf, strlen(buf) + 1); 670 } 671 *ret_label = 0; 672 dfsan_set_label(0, result, sizeof(struct passwd*)); 673 return ret; 674 } 675 676 SANITIZER_INTERFACE_ATTRIBUTE 677 int __dfsw_poll(struct pollfd *fds, nfds_t nfds, int timeout, 678 dfsan_label dfs_label, dfsan_label nfds_label, 679 dfsan_label timeout_label, dfsan_label *ret_label) { 680 int ret = poll(fds, nfds, timeout); 681 if (ret >= 0) { 682 for (; nfds > 0; --nfds) { 683 dfsan_set_label(0, &fds[nfds - 1].revents, sizeof(fds[nfds - 1].revents)); 684 } 685 } 686 *ret_label = 0; 687 return ret; 688 } 689 690 SANITIZER_INTERFACE_ATTRIBUTE 691 int __dfsw_select(int nfds, fd_set *readfds, fd_set *writefds, 692 fd_set *exceptfds, struct timeval *timeout, 693 dfsan_label nfds_label, dfsan_label readfds_label, 694 dfsan_label writefds_label, dfsan_label exceptfds_label, 695 dfsan_label timeout_label, dfsan_label *ret_label) { 696 int ret = select(nfds, readfds, writefds, exceptfds, timeout); 697 // Clear everything (also on error) since their content is either set or 698 // undefined. 699 if (readfds) { 700 dfsan_set_label(0, readfds, sizeof(fd_set)); 701 } 702 if (writefds) { 703 dfsan_set_label(0, writefds, sizeof(fd_set)); 704 } 705 if (exceptfds) { 706 dfsan_set_label(0, exceptfds, sizeof(fd_set)); 707 } 708 dfsan_set_label(0, timeout, sizeof(struct timeval)); 709 *ret_label = 0; 710 return ret; 711 } 712 713 SANITIZER_INTERFACE_ATTRIBUTE 714 int __dfsw_sched_getaffinity(pid_t pid, size_t cpusetsize, cpu_set_t *mask, 715 dfsan_label pid_label, 716 dfsan_label cpusetsize_label, 717 dfsan_label mask_label, dfsan_label *ret_label) { 718 int ret = sched_getaffinity(pid, cpusetsize, mask); 719 if (ret == 0) { 720 dfsan_set_label(0, mask, cpusetsize); 721 } 722 *ret_label = 0; 723 return ret; 724 } 725 726 SANITIZER_INTERFACE_ATTRIBUTE 727 int __dfsw_sigemptyset(sigset_t *set, dfsan_label set_label, 728 dfsan_label *ret_label) { 729 int ret = sigemptyset(set); 730 dfsan_set_label(0, set, sizeof(sigset_t)); 731 return ret; 732 } 733 734 SANITIZER_INTERFACE_ATTRIBUTE 735 int __dfsw_sigaction(int signum, const struct sigaction *act, 736 struct sigaction *oldact, dfsan_label signum_label, 737 dfsan_label act_label, dfsan_label oldact_label, 738 dfsan_label *ret_label) { 739 int ret = sigaction(signum, act, oldact); 740 if (oldact) { 741 dfsan_set_label(0, oldact, sizeof(struct sigaction)); 742 } 743 *ret_label = 0; 744 return ret; 745 } 746 747 SANITIZER_INTERFACE_ATTRIBUTE 748 int __dfsw_gettimeofday(struct timeval *tv, struct timezone *tz, 749 dfsan_label tv_label, dfsan_label tz_label, 750 dfsan_label *ret_label) { 751 int ret = gettimeofday(tv, tz); 752 if (tv) { 753 dfsan_set_label(0, tv, sizeof(struct timeval)); 754 } 755 if (tz) { 756 dfsan_set_label(0, tz, sizeof(struct timezone)); 757 } 758 *ret_label = 0; 759 return ret; 760 } 761 762 SANITIZER_INTERFACE_ATTRIBUTE void *__dfsw_memchr(void *s, int c, size_t n, 763 dfsan_label s_label, 764 dfsan_label c_label, 765 dfsan_label n_label, 766 dfsan_label *ret_label) { 767 void *ret = memchr(s, c, n); 768 if (flags().strict_data_dependencies) { 769 *ret_label = ret ? s_label : 0; 770 } else { 771 size_t len = 772 ret ? reinterpret_cast<char *>(ret) - reinterpret_cast<char *>(s) + 1 773 : n; 774 *ret_label = 775 dfsan_union(dfsan_read_label(s, len), dfsan_union(s_label, c_label)); 776 } 777 return ret; 778 } 779 780 SANITIZER_INTERFACE_ATTRIBUTE char *__dfsw_strrchr(char *s, int c, 781 dfsan_label s_label, 782 dfsan_label c_label, 783 dfsan_label *ret_label) { 784 char *ret = strrchr(s, c); 785 if (flags().strict_data_dependencies) { 786 *ret_label = ret ? s_label : 0; 787 } else { 788 *ret_label = 789 dfsan_union(dfsan_read_label(s, strlen(s) + 1), 790 dfsan_union(s_label, c_label)); 791 } 792 793 return ret; 794 } 795 796 SANITIZER_INTERFACE_ATTRIBUTE char *__dfsw_strstr(char *haystack, char *needle, 797 dfsan_label haystack_label, 798 dfsan_label needle_label, 799 dfsan_label *ret_label) { 800 char *ret = strstr(haystack, needle); 801 if (flags().strict_data_dependencies) { 802 *ret_label = ret ? haystack_label : 0; 803 } else { 804 size_t len = ret ? ret + strlen(needle) - haystack : strlen(haystack) + 1; 805 *ret_label = 806 dfsan_union(dfsan_read_label(haystack, len), 807 dfsan_union(dfsan_read_label(needle, strlen(needle) + 1), 808 dfsan_union(haystack_label, needle_label))); 809 } 810 811 return ret; 812 } 813 814 SANITIZER_INTERFACE_ATTRIBUTE int __dfsw_nanosleep(const struct timespec *req, 815 struct timespec *rem, 816 dfsan_label req_label, 817 dfsan_label rem_label, 818 dfsan_label *ret_label) { 819 int ret = nanosleep(req, rem); 820 *ret_label = 0; 821 if (ret == -1) { 822 // Interrupted by a signal, rem is filled with the remaining time. 823 dfsan_set_label(0, rem, sizeof(struct timespec)); 824 } 825 return ret; 826 } 827 828 SANITIZER_INTERFACE_ATTRIBUTE int 829 __dfsw_socketpair(int domain, int type, int protocol, int sv[2], 830 dfsan_label domain_label, dfsan_label type_label, 831 dfsan_label protocol_label, dfsan_label sv_label, 832 dfsan_label *ret_label) { 833 int ret = socketpair(domain, type, protocol, sv); 834 *ret_label = 0; 835 if (ret == 0) { 836 dfsan_set_label(0, sv, sizeof(*sv) * 2); 837 } 838 return ret; 839 } 840 841 // Type of the trampoline function passed to the custom version of 842 // dfsan_set_write_callback. 843 typedef void (*write_trampoline_t)( 844 void *callback, 845 int fd, const void *buf, ssize_t count, 846 dfsan_label fd_label, dfsan_label buf_label, dfsan_label count_label); 847 848 // Calls to dfsan_set_write_callback() set the values in this struct. 849 // Calls to the custom version of write() read (and invoke) them. 850 static struct { 851 write_trampoline_t write_callback_trampoline = nullptr; 852 void *write_callback = nullptr; 853 } write_callback_info; 854 855 SANITIZER_INTERFACE_ATTRIBUTE void 856 __dfsw_dfsan_set_write_callback( 857 write_trampoline_t write_callback_trampoline, 858 void *write_callback, 859 dfsan_label write_callback_label, 860 dfsan_label *ret_label) { 861 write_callback_info.write_callback_trampoline = write_callback_trampoline; 862 write_callback_info.write_callback = write_callback; 863 } 864 865 SANITIZER_INTERFACE_ATTRIBUTE int 866 __dfsw_write(int fd, const void *buf, size_t count, 867 dfsan_label fd_label, dfsan_label buf_label, 868 dfsan_label count_label, dfsan_label *ret_label) { 869 if (write_callback_info.write_callback) { 870 write_callback_info.write_callback_trampoline( 871 write_callback_info.write_callback, 872 fd, buf, count, 873 fd_label, buf_label, count_label); 874 } 875 876 *ret_label = 0; 877 return write(fd, buf, count); 878 } 879 } // namespace __dfsan 880 881 // Type used to extract a dfsan_label with va_arg() 882 typedef int dfsan_label_va; 883 884 // Formats a chunk either a constant string or a single format directive (e.g., 885 // '%.3f'). 886 struct Formatter { 887 Formatter(char *str_, const char *fmt_, size_t size_) 888 : str(str_), str_off(0), size(size_), fmt_start(fmt_), fmt_cur(fmt_), 889 width(-1) {} 890 891 int format() { 892 char *tmp_fmt = build_format_string(); 893 int retval = 894 snprintf(str + str_off, str_off < size ? size - str_off : 0, tmp_fmt, 895 0 /* used only to avoid warnings */); 896 free(tmp_fmt); 897 return retval; 898 } 899 900 template <typename T> int format(T arg) { 901 char *tmp_fmt = build_format_string(); 902 int retval; 903 if (width >= 0) { 904 retval = snprintf(str + str_off, str_off < size ? size - str_off : 0, 905 tmp_fmt, width, arg); 906 } else { 907 retval = snprintf(str + str_off, str_off < size ? size - str_off : 0, 908 tmp_fmt, arg); 909 } 910 free(tmp_fmt); 911 return retval; 912 } 913 914 char *build_format_string() { 915 size_t fmt_size = fmt_cur - fmt_start + 1; 916 char *new_fmt = (char *)malloc(fmt_size + 1); 917 assert(new_fmt); 918 internal_memcpy(new_fmt, fmt_start, fmt_size); 919 new_fmt[fmt_size] = '\0'; 920 return new_fmt; 921 } 922 923 char *str_cur() { return str + str_off; } 924 925 size_t num_written_bytes(int retval) { 926 if (retval < 0) { 927 return 0; 928 } 929 930 size_t num_avail = str_off < size ? size - str_off : 0; 931 if (num_avail == 0) { 932 return 0; 933 } 934 935 size_t num_written = retval; 936 // A return value of {v,}snprintf of size or more means that the output was 937 // truncated. 938 if (num_written >= num_avail) { 939 num_written -= num_avail; 940 } 941 942 return num_written; 943 } 944 945 char *str; 946 size_t str_off; 947 size_t size; 948 const char *fmt_start; 949 const char *fmt_cur; 950 int width; 951 }; 952 953 // Formats the input and propagates the input labels to the output. The output 954 // is stored in 'str'. 'size' bounds the number of output bytes. 'format' and 955 // 'ap' are the format string and the list of arguments for formatting. Returns 956 // the return value vsnprintf would return. 957 // 958 // The function tokenizes the format string in chunks representing either a 959 // constant string or a single format directive (e.g., '%.3f') and formats each 960 // chunk independently into the output string. This approach allows to figure 961 // out which bytes of the output string depends on which argument and thus to 962 // propagate labels more precisely. 963 // 964 // WARNING: This implementation does not support conversion specifiers with 965 // positional arguments. 966 static int format_buffer(char *str, size_t size, const char *fmt, 967 dfsan_label *va_labels, dfsan_label *ret_label, 968 va_list ap) { 969 Formatter formatter(str, fmt, size); 970 971 while (*formatter.fmt_cur) { 972 formatter.fmt_start = formatter.fmt_cur; 973 formatter.width = -1; 974 int retval = 0; 975 976 if (*formatter.fmt_cur != '%') { 977 // Ordinary character. Consume all the characters until a '%' or the end 978 // of the string. 979 for (; *(formatter.fmt_cur + 1) && *(formatter.fmt_cur + 1) != '%'; 980 ++formatter.fmt_cur) {} 981 retval = formatter.format(); 982 dfsan_set_label(0, formatter.str_cur(), 983 formatter.num_written_bytes(retval)); 984 } else { 985 // Conversion directive. Consume all the characters until a conversion 986 // specifier or the end of the string. 987 bool end_fmt = false; 988 for (; *formatter.fmt_cur && !end_fmt; ) { 989 switch (*++formatter.fmt_cur) { 990 case 'd': 991 case 'i': 992 case 'o': 993 case 'u': 994 case 'x': 995 case 'X': 996 switch (*(formatter.fmt_cur - 1)) { 997 case 'h': 998 // Also covers the 'hh' case (since the size of the arg is still 999 // an int). 1000 retval = formatter.format(va_arg(ap, int)); 1001 break; 1002 case 'l': 1003 if (formatter.fmt_cur - formatter.fmt_start >= 2 && 1004 *(formatter.fmt_cur - 2) == 'l') { 1005 retval = formatter.format(va_arg(ap, long long int)); 1006 } else { 1007 retval = formatter.format(va_arg(ap, long int)); 1008 } 1009 break; 1010 case 'q': 1011 retval = formatter.format(va_arg(ap, long long int)); 1012 break; 1013 case 'j': 1014 retval = formatter.format(va_arg(ap, intmax_t)); 1015 break; 1016 case 'z': 1017 case 't': 1018 retval = formatter.format(va_arg(ap, size_t)); 1019 break; 1020 default: 1021 retval = formatter.format(va_arg(ap, int)); 1022 } 1023 dfsan_set_label(*va_labels++, formatter.str_cur(), 1024 formatter.num_written_bytes(retval)); 1025 end_fmt = true; 1026 break; 1027 1028 case 'a': 1029 case 'A': 1030 case 'e': 1031 case 'E': 1032 case 'f': 1033 case 'F': 1034 case 'g': 1035 case 'G': 1036 if (*(formatter.fmt_cur - 1) == 'L') { 1037 retval = formatter.format(va_arg(ap, long double)); 1038 } else { 1039 retval = formatter.format(va_arg(ap, double)); 1040 } 1041 dfsan_set_label(*va_labels++, formatter.str_cur(), 1042 formatter.num_written_bytes(retval)); 1043 end_fmt = true; 1044 break; 1045 1046 case 'c': 1047 retval = formatter.format(va_arg(ap, int)); 1048 dfsan_set_label(*va_labels++, formatter.str_cur(), 1049 formatter.num_written_bytes(retval)); 1050 end_fmt = true; 1051 break; 1052 1053 case 's': { 1054 char *arg = va_arg(ap, char *); 1055 retval = formatter.format(arg); 1056 va_labels++; 1057 internal_memcpy(shadow_for(formatter.str_cur()), shadow_for(arg), 1058 sizeof(dfsan_label) * 1059 formatter.num_written_bytes(retval)); 1060 end_fmt = true; 1061 break; 1062 } 1063 1064 case 'p': 1065 retval = formatter.format(va_arg(ap, void *)); 1066 dfsan_set_label(*va_labels++, formatter.str_cur(), 1067 formatter.num_written_bytes(retval)); 1068 end_fmt = true; 1069 break; 1070 1071 case 'n': { 1072 int *ptr = va_arg(ap, int *); 1073 *ptr = (int)formatter.str_off; 1074 va_labels++; 1075 dfsan_set_label(0, ptr, sizeof(ptr)); 1076 end_fmt = true; 1077 break; 1078 } 1079 1080 case '%': 1081 retval = formatter.format(); 1082 dfsan_set_label(0, formatter.str_cur(), 1083 formatter.num_written_bytes(retval)); 1084 end_fmt = true; 1085 break; 1086 1087 case '*': 1088 formatter.width = va_arg(ap, int); 1089 va_labels++; 1090 break; 1091 1092 default: 1093 break; 1094 } 1095 } 1096 } 1097 1098 if (retval < 0) { 1099 return retval; 1100 } 1101 1102 formatter.fmt_cur++; 1103 formatter.str_off += retval; 1104 } 1105 1106 *ret_label = 0; 1107 1108 // Number of bytes written in total. 1109 return formatter.str_off; 1110 } 1111 1112 extern "C" { 1113 SANITIZER_INTERFACE_ATTRIBUTE 1114 int __dfsw_sprintf(char *str, const char *format, dfsan_label str_label, 1115 dfsan_label format_label, dfsan_label *va_labels, 1116 dfsan_label *ret_label, ...) { 1117 va_list ap; 1118 va_start(ap, ret_label); 1119 int ret = format_buffer(str, ~0ul, format, va_labels, ret_label, ap); 1120 va_end(ap); 1121 return ret; 1122 } 1123 1124 SANITIZER_INTERFACE_ATTRIBUTE 1125 int __dfsw_snprintf(char *str, size_t size, const char *format, 1126 dfsan_label str_label, dfsan_label size_label, 1127 dfsan_label format_label, dfsan_label *va_labels, 1128 dfsan_label *ret_label, ...) { 1129 va_list ap; 1130 va_start(ap, ret_label); 1131 int ret = format_buffer(str, size, format, va_labels, ret_label, ap); 1132 va_end(ap); 1133 return ret; 1134 } 1135 } // extern "C" 1136
