1 //===-- dfsan.cpp ---------------------------------------------------------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 // 9 // This file is a part of DataFlowSanitizer. 10 // 11 // This file defines the custom functions listed in done_abilist.txt. 12 //===----------------------------------------------------------------------===// 13 14 #include <arpa/inet.h> 15 #include <assert.h> 16 #include <ctype.h> 17 #include <dlfcn.h> 18 #include <link.h> 19 #include <poll.h> 20 #include <pthread.h> 21 #include <pwd.h> 22 #include <sched.h> 23 #include <signal.h> 24 #include <stdarg.h> 25 #include <stdint.h> 26 #include <stdio.h> 27 #include <stdlib.h> 28 #include <string.h> 29 #include <sys/epoll.h> 30 #include <sys/resource.h> 31 #include <sys/select.h> 32 #include <sys/socket.h> 33 #include <sys/stat.h> 34 #include <sys/time.h> 35 #include <sys/types.h> 36 #include <time.h> 37 #include <unistd.h> 38 39 #include "dfsan/dfsan.h" 40 #include "dfsan/dfsan_thread.h" 41 #include "sanitizer_common/sanitizer_common.h" 42 #include "sanitizer_common/sanitizer_internal_defs.h" 43 #include "sanitizer_common/sanitizer_linux.h" 44 45 using namespace __dfsan; 46 47 #define CALL_WEAK_INTERCEPTOR_HOOK(f, ...) \ 48 do { \ 49 if (f) \ 50 f(__VA_ARGS__); \ 51 } while (false) 52 #define DECLARE_WEAK_INTERCEPTOR_HOOK(f, ...) \ 53 SANITIZER_INTERFACE_ATTRIBUTE SANITIZER_WEAK_ATTRIBUTE void f(__VA_ARGS__); 54 55 // Async-safe, non-reentrant spin lock. 56 class SignalSpinLocker { 57 public: 58 SignalSpinLocker() { 59 sigset_t all_set; 60 sigfillset(&all_set); 61 pthread_sigmask(SIG_SETMASK, &all_set, &saved_thread_mask_); 62 sigactions_mu.Lock(); 63 } 64 ~SignalSpinLocker() { 65 sigactions_mu.Unlock(); 66 pthread_sigmask(SIG_SETMASK, &saved_thread_mask_, nullptr); 67 } 68 69 private: 70 static StaticSpinMutex sigactions_mu; 71 sigset_t saved_thread_mask_; 72 73 SignalSpinLocker(const SignalSpinLocker &) = delete; 74 SignalSpinLocker &operator=(const SignalSpinLocker &) = delete; 75 }; 76 77 StaticSpinMutex SignalSpinLocker::sigactions_mu; 78 79 extern "C" { 80 SANITIZER_INTERFACE_ATTRIBUTE int 81 __dfsw_stat(const char *path, struct stat *buf, dfsan_label path_label, 82 dfsan_label buf_label, dfsan_label *ret_label) { 83 int ret = stat(path, buf); 84 if (ret == 0) 85 dfsan_set_label(0, buf, sizeof(struct stat)); 86 *ret_label = 0; 87 return ret; 88 } 89 90 SANITIZER_INTERFACE_ATTRIBUTE int __dfsw_fstat(int fd, struct stat *buf, 91 dfsan_label fd_label, 92 dfsan_label buf_label, 93 dfsan_label *ret_label) { 94 int ret = fstat(fd, buf); 95 if (ret == 0) 96 dfsan_set_label(0, buf, sizeof(struct stat)); 97 *ret_label = 0; 98 return ret; 99 } 100 101 SANITIZER_INTERFACE_ATTRIBUTE char *__dfsw_strchr(const char *s, int c, 102 dfsan_label s_label, 103 dfsan_label c_label, 104 dfsan_label *ret_label) { 105 for (size_t i = 0;; ++i) { 106 if (s[i] == c || s[i] == 0) { 107 if (flags().strict_data_dependencies) { 108 *ret_label = s_label; 109 } else { 110 *ret_label = dfsan_union(dfsan_read_label(s, i + 1), 111 dfsan_union(s_label, c_label)); 112 } 113 114 // If s[i] is the \0 at the end of the string, and \0 is not the 115 // character we are searching for, then return null. 116 if (s[i] == 0 && c != 0) { 117 return nullptr; 118 } 119 return const_cast<char *>(s + i); 120 } 121 } 122 } 123 124 SANITIZER_INTERFACE_ATTRIBUTE char *__dfsw_strpbrk(const char *s, 125 const char *accept, 126 dfsan_label s_label, 127 dfsan_label accept_label, 128 dfsan_label *ret_label) { 129 const char *ret = strpbrk(s, accept); 130 if (flags().strict_data_dependencies) { 131 *ret_label = ret ? s_label : 0; 132 } else { 133 size_t s_bytes_read = (ret ? ret - s : strlen(s)) + 1; 134 *ret_label = 135 dfsan_union(dfsan_read_label(s, s_bytes_read), 136 dfsan_union(dfsan_read_label(accept, strlen(accept) + 1), 137 dfsan_union(s_label, accept_label))); 138 } 139 return const_cast<char *>(ret); 140 } 141 142 static int dfsan_memcmp_bcmp(const void *s1, const void *s2, size_t n, 143 dfsan_label s1_label, dfsan_label s2_label, 144 dfsan_label n_label, dfsan_label *ret_label) { 145 const char *cs1 = (const char *) s1, *cs2 = (const char *) s2; 146 for (size_t i = 0; i != n; ++i) { 147 if (cs1[i] != cs2[i]) { 148 if (flags().strict_data_dependencies) { 149 *ret_label = 0; 150 } else { 151 *ret_label = dfsan_union(dfsan_read_label(cs1, i + 1), 152 dfsan_read_label(cs2, i + 1)); 153 } 154 return cs1[i] - cs2[i]; 155 } 156 } 157 158 if (flags().strict_data_dependencies) { 159 *ret_label = 0; 160 } else { 161 *ret_label = dfsan_union(dfsan_read_label(cs1, n), 162 dfsan_read_label(cs2, n)); 163 } 164 return 0; 165 } 166 167 DECLARE_WEAK_INTERCEPTOR_HOOK(dfsan_weak_hook_memcmp, uptr caller_pc, 168 const void *s1, const void *s2, size_t n, 169 dfsan_label s1_label, dfsan_label s2_label, 170 dfsan_label n_label) 171 172 SANITIZER_INTERFACE_ATTRIBUTE int __dfsw_memcmp(const void *s1, const void *s2, 173 size_t n, dfsan_label s1_label, 174 dfsan_label s2_label, 175 dfsan_label n_label, 176 dfsan_label *ret_label) { 177 CALL_WEAK_INTERCEPTOR_HOOK(dfsan_weak_hook_memcmp, GET_CALLER_PC(), s1, s2, n, 178 s1_label, s2_label, n_label); 179 return dfsan_memcmp_bcmp(s1, s2, n, s1_label, s2_label, n_label, ret_label); 180 } 181 182 SANITIZER_INTERFACE_ATTRIBUTE int __dfsw_bcmp(const void *s1, const void *s2, 183 size_t n, dfsan_label s1_label, 184 dfsan_label s2_label, 185 dfsan_label n_label, 186 dfsan_label *ret_label) { 187 return dfsan_memcmp_bcmp(s1, s2, n, s1_label, s2_label, n_label, ret_label); 188 } 189 190 DECLARE_WEAK_INTERCEPTOR_HOOK(dfsan_weak_hook_strcmp, uptr caller_pc, 191 const char *s1, const char *s2, 192 dfsan_label s1_label, dfsan_label s2_label) 193 194 SANITIZER_INTERFACE_ATTRIBUTE int __dfsw_strcmp(const char *s1, const char *s2, 195 dfsan_label s1_label, 196 dfsan_label s2_label, 197 dfsan_label *ret_label) { 198 CALL_WEAK_INTERCEPTOR_HOOK(dfsan_weak_hook_strcmp, GET_CALLER_PC(), s1, s2, 199 s1_label, s2_label); 200 for (size_t i = 0;; ++i) { 201 if (s1[i] != s2[i] || s1[i] == 0 || s2[i] == 0) { 202 if (flags().strict_data_dependencies) { 203 *ret_label = 0; 204 } else { 205 *ret_label = dfsan_union(dfsan_read_label(s1, i + 1), 206 dfsan_read_label(s2, i + 1)); 207 } 208 return s1[i] - s2[i]; 209 } 210 } 211 return 0; 212 } 213 214 SANITIZER_INTERFACE_ATTRIBUTE int 215 __dfsw_strcasecmp(const char *s1, const char *s2, dfsan_label s1_label, 216 dfsan_label s2_label, dfsan_label *ret_label) { 217 for (size_t i = 0;; ++i) { 218 char s1_lower = tolower(s1[i]); 219 char s2_lower = tolower(s2[i]); 220 221 if (s1_lower != s2_lower || s1[i] == 0 || s2[i] == 0) { 222 if (flags().strict_data_dependencies) { 223 *ret_label = 0; 224 } else { 225 *ret_label = dfsan_union(dfsan_read_label(s1, i + 1), 226 dfsan_read_label(s2, i + 1)); 227 } 228 return s1_lower - s2_lower; 229 } 230 } 231 return 0; 232 } 233 234 DECLARE_WEAK_INTERCEPTOR_HOOK(dfsan_weak_hook_strncmp, uptr caller_pc, 235 const char *s1, const char *s2, size_t n, 236 dfsan_label s1_label, dfsan_label s2_label, 237 dfsan_label n_label) 238 239 SANITIZER_INTERFACE_ATTRIBUTE int __dfsw_strncmp(const char *s1, const char *s2, 240 size_t n, dfsan_label s1_label, 241 dfsan_label s2_label, 242 dfsan_label n_label, 243 dfsan_label *ret_label) { 244 if (n == 0) { 245 *ret_label = 0; 246 return 0; 247 } 248 249 CALL_WEAK_INTERCEPTOR_HOOK(dfsan_weak_hook_strncmp, GET_CALLER_PC(), s1, s2, 250 n, s1_label, s2_label, n_label); 251 252 for (size_t i = 0;; ++i) { 253 if (s1[i] != s2[i] || s1[i] == 0 || s2[i] == 0 || i == n - 1) { 254 if (flags().strict_data_dependencies) { 255 *ret_label = 0; 256 } else { 257 *ret_label = dfsan_union(dfsan_read_label(s1, i + 1), 258 dfsan_read_label(s2, i + 1)); 259 } 260 return s1[i] - s2[i]; 261 } 262 } 263 return 0; 264 } 265 266 SANITIZER_INTERFACE_ATTRIBUTE int 267 __dfsw_strncasecmp(const char *s1, const char *s2, size_t n, 268 dfsan_label s1_label, dfsan_label s2_label, 269 dfsan_label n_label, dfsan_label *ret_label) { 270 if (n == 0) { 271 *ret_label = 0; 272 return 0; 273 } 274 275 for (size_t i = 0;; ++i) { 276 char s1_lower = tolower(s1[i]); 277 char s2_lower = tolower(s2[i]); 278 279 if (s1_lower != s2_lower || s1[i] == 0 || s2[i] == 0 || i == n - 1) { 280 if (flags().strict_data_dependencies) { 281 *ret_label = 0; 282 } else { 283 *ret_label = dfsan_union(dfsan_read_label(s1, i + 1), 284 dfsan_read_label(s2, i + 1)); 285 } 286 return s1_lower - s2_lower; 287 } 288 } 289 return 0; 290 } 291 292 SANITIZER_INTERFACE_ATTRIBUTE void *__dfsw_calloc(size_t nmemb, size_t size, 293 dfsan_label nmemb_label, 294 dfsan_label size_label, 295 dfsan_label *ret_label) { 296 void *p = calloc(nmemb, size); 297 dfsan_set_label(0, p, nmemb * size); 298 *ret_label = 0; 299 return p; 300 } 301 302 SANITIZER_INTERFACE_ATTRIBUTE size_t 303 __dfsw_strlen(const char *s, dfsan_label s_label, dfsan_label *ret_label) { 304 size_t ret = strlen(s); 305 if (flags().strict_data_dependencies) { 306 *ret_label = 0; 307 } else { 308 *ret_label = dfsan_read_label(s, ret + 1); 309 } 310 return ret; 311 } 312 313 static void *dfsan_memmove(void *dest, const void *src, size_t n) { 314 dfsan_label *sdest = shadow_for(dest); 315 const dfsan_label *ssrc = shadow_for(src); 316 internal_memmove((void *)sdest, (const void *)ssrc, n * sizeof(dfsan_label)); 317 return internal_memmove(dest, src, n); 318 } 319 320 static void *dfsan_memcpy(void *dest, const void *src, size_t n) { 321 dfsan_label *sdest = shadow_for(dest); 322 const dfsan_label *ssrc = shadow_for(src); 323 internal_memcpy((void *)sdest, (const void *)ssrc, n * sizeof(dfsan_label)); 324 return internal_memcpy(dest, src, n); 325 } 326 327 static void dfsan_memset(void *s, int c, dfsan_label c_label, size_t n) { 328 internal_memset(s, c, n); 329 dfsan_set_label(c_label, s, n); 330 } 331 332 SANITIZER_INTERFACE_ATTRIBUTE 333 void *__dfsw_memcpy(void *dest, const void *src, size_t n, 334 dfsan_label dest_label, dfsan_label src_label, 335 dfsan_label n_label, dfsan_label *ret_label) { 336 *ret_label = dest_label; 337 return dfsan_memcpy(dest, src, n); 338 } 339 340 SANITIZER_INTERFACE_ATTRIBUTE 341 void *__dfsw_memmove(void *dest, const void *src, size_t n, 342 dfsan_label dest_label, dfsan_label src_label, 343 dfsan_label n_label, dfsan_label *ret_label) { 344 *ret_label = dest_label; 345 return dfsan_memmove(dest, src, n); 346 } 347 348 SANITIZER_INTERFACE_ATTRIBUTE 349 void *__dfsw_memset(void *s, int c, size_t n, 350 dfsan_label s_label, dfsan_label c_label, 351 dfsan_label n_label, dfsan_label *ret_label) { 352 dfsan_memset(s, c, c_label, n); 353 *ret_label = s_label; 354 return s; 355 } 356 357 SANITIZER_INTERFACE_ATTRIBUTE char *__dfsw_strcat(char *dest, const char *src, 358 dfsan_label dest_label, 359 dfsan_label src_label, 360 dfsan_label *ret_label) { 361 size_t dest_len = strlen(dest); 362 char *ret = strcat(dest, src); 363 dfsan_label *sdest = shadow_for(dest + dest_len); 364 const dfsan_label *ssrc = shadow_for(src); 365 internal_memcpy((void *)sdest, (const void *)ssrc, 366 strlen(src) * sizeof(dfsan_label)); 367 *ret_label = dest_label; 368 return ret; 369 } 370 371 SANITIZER_INTERFACE_ATTRIBUTE char * 372 __dfsw_strdup(const char *s, dfsan_label s_label, dfsan_label *ret_label) { 373 size_t len = strlen(s); 374 void *p = malloc(len+1); 375 dfsan_memcpy(p, s, len+1); 376 *ret_label = 0; 377 return static_cast<char *>(p); 378 } 379 380 SANITIZER_INTERFACE_ATTRIBUTE char * 381 __dfsw_strncpy(char *s1, const char *s2, size_t n, dfsan_label s1_label, 382 dfsan_label s2_label, dfsan_label n_label, 383 dfsan_label *ret_label) { 384 size_t len = strlen(s2); 385 if (len < n) { 386 dfsan_memcpy(s1, s2, len+1); 387 dfsan_memset(s1+len+1, 0, 0, n-len-1); 388 } else { 389 dfsan_memcpy(s1, s2, n); 390 } 391 392 *ret_label = s1_label; 393 return s1; 394 } 395 396 SANITIZER_INTERFACE_ATTRIBUTE ssize_t 397 __dfsw_pread(int fd, void *buf, size_t count, off_t offset, 398 dfsan_label fd_label, dfsan_label buf_label, 399 dfsan_label count_label, dfsan_label offset_label, 400 dfsan_label *ret_label) { 401 ssize_t ret = pread(fd, buf, count, offset); 402 if (ret > 0) 403 dfsan_set_label(0, buf, ret); 404 *ret_label = 0; 405 return ret; 406 } 407 408 SANITIZER_INTERFACE_ATTRIBUTE ssize_t 409 __dfsw_read(int fd, void *buf, size_t count, 410 dfsan_label fd_label, dfsan_label buf_label, 411 dfsan_label count_label, 412 dfsan_label *ret_label) { 413 ssize_t ret = read(fd, buf, count); 414 if (ret > 0) 415 dfsan_set_label(0, buf, ret); 416 *ret_label = 0; 417 return ret; 418 } 419 420 SANITIZER_INTERFACE_ATTRIBUTE int __dfsw_clock_gettime(clockid_t clk_id, 421 struct timespec *tp, 422 dfsan_label clk_id_label, 423 dfsan_label tp_label, 424 dfsan_label *ret_label) { 425 int ret = clock_gettime(clk_id, tp); 426 if (ret == 0) 427 dfsan_set_label(0, tp, sizeof(struct timespec)); 428 *ret_label = 0; 429 return ret; 430 } 431 432 static void unpoison(const void *ptr, uptr size) { 433 dfsan_set_label(0, const_cast<void *>(ptr), size); 434 } 435 436 // dlopen() ultimately calls mmap() down inside the loader, which generally 437 // doesn't participate in dynamic symbol resolution. Therefore we won't 438 // intercept its calls to mmap, and we have to hook it here. 439 SANITIZER_INTERFACE_ATTRIBUTE void * 440 __dfsw_dlopen(const char *filename, int flag, dfsan_label filename_label, 441 dfsan_label flag_label, dfsan_label *ret_label) { 442 void *handle = dlopen(filename, flag); 443 link_map *map = GET_LINK_MAP_BY_DLOPEN_HANDLE(handle); 444 if (map) 445 ForEachMappedRegion(map, unpoison); 446 *ret_label = 0; 447 return handle; 448 } 449 450 static void *DFsanThreadStartFunc(void *arg) { 451 DFsanThread *t = (DFsanThread *)arg; 452 SetCurrentThread(t); 453 return t->ThreadStart(); 454 } 455 456 static int dfsan_pthread_create(pthread_t *thread, const pthread_attr_t *attr, 457 void *start_routine_trampoline, 458 void *start_routine, void *arg, 459 dfsan_label *ret_label) { 460 pthread_attr_t myattr; 461 if (!attr) { 462 pthread_attr_init(&myattr); 463 attr = &myattr; 464 } 465 466 // Ensure that the thread stack is large enough to hold all TLS data. 467 AdjustStackSize((void *)(const_cast<pthread_attr_t *>(attr))); 468 469 DFsanThread *t = DFsanThread::Create(start_routine_trampoline, 470 (thread_callback_t)start_routine, arg); 471 int res = pthread_create(thread, attr, DFsanThreadStartFunc, t); 472 473 if (attr == &myattr) 474 pthread_attr_destroy(&myattr); 475 *ret_label = 0; 476 return res; 477 } 478 479 SANITIZER_INTERFACE_ATTRIBUTE int __dfsw_pthread_create( 480 pthread_t *thread, const pthread_attr_t *attr, 481 void *(*start_routine_trampoline)(void *, void *, dfsan_label, 482 dfsan_label *), 483 void *start_routine, void *arg, dfsan_label thread_label, 484 dfsan_label attr_label, dfsan_label start_routine_label, 485 dfsan_label arg_label, dfsan_label *ret_label) { 486 return dfsan_pthread_create(thread, attr, (void *)start_routine_trampoline, 487 start_routine, arg, ret_label); 488 } 489 490 SANITIZER_INTERFACE_ATTRIBUTE int __dfsw_pthread_join(pthread_t thread, 491 void **retval, 492 dfsan_label thread_label, 493 dfsan_label retval_label, 494 dfsan_label *ret_label) { 495 int ret = pthread_join(thread, retval); 496 if (ret == 0 && retval) 497 dfsan_set_label(0, retval, sizeof(*retval)); 498 *ret_label = 0; 499 return ret; 500 } 501 502 struct dl_iterate_phdr_info { 503 int (*callback_trampoline)(void *callback, struct dl_phdr_info *info, 504 size_t size, void *data, dfsan_label info_label, 505 dfsan_label size_label, dfsan_label data_label, 506 dfsan_label *ret_label); 507 void *callback; 508 void *data; 509 }; 510 511 int dl_iterate_phdr_cb(struct dl_phdr_info *info, size_t size, void *data) { 512 dl_iterate_phdr_info *dipi = (dl_iterate_phdr_info *)data; 513 dfsan_set_label(0, *info); 514 dfsan_set_label(0, const_cast<char *>(info->dlpi_name), 515 strlen(info->dlpi_name) + 1); 516 dfsan_set_label( 517 0, const_cast<char *>(reinterpret_cast<const char *>(info->dlpi_phdr)), 518 sizeof(*info->dlpi_phdr) * info->dlpi_phnum); 519 dfsan_label ret_label; 520 return dipi->callback_trampoline(dipi->callback, info, size, dipi->data, 0, 0, 521 0, &ret_label); 522 } 523 524 SANITIZER_INTERFACE_ATTRIBUTE int __dfsw_dl_iterate_phdr( 525 int (*callback_trampoline)(void *callback, struct dl_phdr_info *info, 526 size_t size, void *data, dfsan_label info_label, 527 dfsan_label size_label, dfsan_label data_label, 528 dfsan_label *ret_label), 529 void *callback, void *data, dfsan_label callback_label, 530 dfsan_label data_label, dfsan_label *ret_label) { 531 dl_iterate_phdr_info dipi = { callback_trampoline, callback, data }; 532 *ret_label = 0; 533 return dl_iterate_phdr(dl_iterate_phdr_cb, &dipi); 534 } 535 536 // This function is only available for glibc 2.27 or newer. Mark it weak so 537 // linking succeeds with older glibcs. 538 SANITIZER_WEAK_ATTRIBUTE void _dl_get_tls_static_info(size_t *sizep, 539 size_t *alignp); 540 541 SANITIZER_INTERFACE_ATTRIBUTE void __dfsw__dl_get_tls_static_info( 542 size_t *sizep, size_t *alignp, dfsan_label sizep_label, 543 dfsan_label alignp_label) { 544 assert(_dl_get_tls_static_info); 545 _dl_get_tls_static_info(sizep, alignp); 546 dfsan_set_label(0, sizep, sizeof(*sizep)); 547 dfsan_set_label(0, alignp, sizeof(*alignp)); 548 } 549 550 SANITIZER_INTERFACE_ATTRIBUTE 551 char *__dfsw_ctime_r(const time_t *timep, char *buf, dfsan_label timep_label, 552 dfsan_label buf_label, dfsan_label *ret_label) { 553 char *ret = ctime_r(timep, buf); 554 if (ret) { 555 dfsan_set_label(dfsan_read_label(timep, sizeof(time_t)), buf, 556 strlen(buf) + 1); 557 *ret_label = buf_label; 558 } else { 559 *ret_label = 0; 560 } 561 return ret; 562 } 563 564 SANITIZER_INTERFACE_ATTRIBUTE 565 char *__dfsw_fgets(char *s, int size, FILE *stream, dfsan_label s_label, 566 dfsan_label size_label, dfsan_label stream_label, 567 dfsan_label *ret_label) { 568 char *ret = fgets(s, size, stream); 569 if (ret) { 570 dfsan_set_label(0, ret, strlen(ret) + 1); 571 *ret_label = s_label; 572 } else { 573 *ret_label = 0; 574 } 575 return ret; 576 } 577 578 SANITIZER_INTERFACE_ATTRIBUTE 579 char *__dfsw_getcwd(char *buf, size_t size, dfsan_label buf_label, 580 dfsan_label size_label, dfsan_label *ret_label) { 581 char *ret = getcwd(buf, size); 582 if (ret) { 583 dfsan_set_label(0, ret, strlen(ret) + 1); 584 *ret_label = buf_label; 585 } else { 586 *ret_label = 0; 587 } 588 return ret; 589 } 590 591 SANITIZER_INTERFACE_ATTRIBUTE 592 char *__dfsw_get_current_dir_name(dfsan_label *ret_label) { 593 char *ret = get_current_dir_name(); 594 if (ret) { 595 dfsan_set_label(0, ret, strlen(ret) + 1); 596 } 597 *ret_label = 0; 598 return ret; 599 } 600 601 SANITIZER_INTERFACE_ATTRIBUTE 602 int __dfsw_gethostname(char *name, size_t len, dfsan_label name_label, 603 dfsan_label len_label, dfsan_label *ret_label) { 604 int ret = gethostname(name, len); 605 if (ret == 0) { 606 dfsan_set_label(0, name, strlen(name) + 1); 607 } 608 *ret_label = 0; 609 return ret; 610 } 611 612 SANITIZER_INTERFACE_ATTRIBUTE 613 int __dfsw_getrlimit(int resource, struct rlimit *rlim, 614 dfsan_label resource_label, dfsan_label rlim_label, 615 dfsan_label *ret_label) { 616 int ret = getrlimit(resource, rlim); 617 if (ret == 0) { 618 dfsan_set_label(0, rlim, sizeof(struct rlimit)); 619 } 620 *ret_label = 0; 621 return ret; 622 } 623 624 SANITIZER_INTERFACE_ATTRIBUTE 625 int __dfsw_getrusage(int who, struct rusage *usage, dfsan_label who_label, 626 dfsan_label usage_label, dfsan_label *ret_label) { 627 int ret = getrusage(who, usage); 628 if (ret == 0) { 629 dfsan_set_label(0, usage, sizeof(struct rusage)); 630 } 631 *ret_label = 0; 632 return ret; 633 } 634 635 SANITIZER_INTERFACE_ATTRIBUTE 636 char *__dfsw_strcpy(char *dest, const char *src, dfsan_label dst_label, 637 dfsan_label src_label, dfsan_label *ret_label) { 638 char *ret = strcpy(dest, src); // NOLINT 639 if (ret) { 640 internal_memcpy(shadow_for(dest), shadow_for(src), 641 sizeof(dfsan_label) * (strlen(src) + 1)); 642 } 643 *ret_label = dst_label; 644 return ret; 645 } 646 647 SANITIZER_INTERFACE_ATTRIBUTE 648 long int __dfsw_strtol(const char *nptr, char **endptr, int base, 649 dfsan_label nptr_label, dfsan_label endptr_label, 650 dfsan_label base_label, dfsan_label *ret_label) { 651 char *tmp_endptr; 652 long int ret = strtol(nptr, &tmp_endptr, base); 653 if (endptr) { 654 *endptr = tmp_endptr; 655 } 656 if (tmp_endptr > nptr) { 657 // If *tmp_endptr is '\0' include its label as well. 658 *ret_label = dfsan_union( 659 base_label, 660 dfsan_read_label(nptr, tmp_endptr - nptr + (*tmp_endptr ? 0 : 1))); 661 } else { 662 *ret_label = 0; 663 } 664 return ret; 665 } 666 667 SANITIZER_INTERFACE_ATTRIBUTE 668 double __dfsw_strtod(const char *nptr, char **endptr, 669 dfsan_label nptr_label, dfsan_label endptr_label, 670 dfsan_label *ret_label) { 671 char *tmp_endptr; 672 double ret = strtod(nptr, &tmp_endptr); 673 if (endptr) { 674 *endptr = tmp_endptr; 675 } 676 if (tmp_endptr > nptr) { 677 // If *tmp_endptr is '\0' include its label as well. 678 *ret_label = dfsan_read_label( 679 nptr, 680 tmp_endptr - nptr + (*tmp_endptr ? 0 : 1)); 681 } else { 682 *ret_label = 0; 683 } 684 return ret; 685 } 686 687 SANITIZER_INTERFACE_ATTRIBUTE 688 long long int __dfsw_strtoll(const char *nptr, char **endptr, int base, 689 dfsan_label nptr_label, dfsan_label endptr_label, 690 dfsan_label base_label, dfsan_label *ret_label) { 691 char *tmp_endptr; 692 long long int ret = strtoll(nptr, &tmp_endptr, base); 693 if (endptr) { 694 *endptr = tmp_endptr; 695 } 696 if (tmp_endptr > nptr) { 697 // If *tmp_endptr is '\0' include its label as well. 698 *ret_label = dfsan_union( 699 base_label, 700 dfsan_read_label(nptr, tmp_endptr - nptr + (*tmp_endptr ? 0 : 1))); 701 } else { 702 *ret_label = 0; 703 } 704 return ret; 705 } 706 707 SANITIZER_INTERFACE_ATTRIBUTE 708 unsigned long int __dfsw_strtoul(const char *nptr, char **endptr, int base, 709 dfsan_label nptr_label, dfsan_label endptr_label, 710 dfsan_label base_label, dfsan_label *ret_label) { 711 char *tmp_endptr; 712 unsigned long int ret = strtoul(nptr, &tmp_endptr, base); 713 if (endptr) { 714 *endptr = tmp_endptr; 715 } 716 if (tmp_endptr > nptr) { 717 // If *tmp_endptr is '\0' include its label as well. 718 *ret_label = dfsan_union( 719 base_label, 720 dfsan_read_label(nptr, tmp_endptr - nptr + (*tmp_endptr ? 0 : 1))); 721 } else { 722 *ret_label = 0; 723 } 724 return ret; 725 } 726 727 SANITIZER_INTERFACE_ATTRIBUTE 728 long long unsigned int __dfsw_strtoull(const char *nptr, char **endptr, 729 int base, dfsan_label nptr_label, 730 dfsan_label endptr_label, 731 dfsan_label base_label, 732 dfsan_label *ret_label) { 733 char *tmp_endptr; 734 long long unsigned int ret = strtoull(nptr, &tmp_endptr, base); 735 if (endptr) { 736 *endptr = tmp_endptr; 737 } 738 if (tmp_endptr > nptr) { 739 // If *tmp_endptr is '\0' include its label as well. 740 *ret_label = dfsan_union( 741 base_label, 742 dfsan_read_label(nptr, tmp_endptr - nptr + (*tmp_endptr ? 0 : 1))); 743 } else { 744 *ret_label = 0; 745 } 746 return ret; 747 } 748 749 SANITIZER_INTERFACE_ATTRIBUTE 750 time_t __dfsw_time(time_t *t, dfsan_label t_label, dfsan_label *ret_label) { 751 time_t ret = time(t); 752 if (ret != (time_t) -1 && t) { 753 dfsan_set_label(0, t, sizeof(time_t)); 754 } 755 *ret_label = 0; 756 return ret; 757 } 758 759 SANITIZER_INTERFACE_ATTRIBUTE 760 int __dfsw_inet_pton(int af, const char *src, void *dst, dfsan_label af_label, 761 dfsan_label src_label, dfsan_label dst_label, 762 dfsan_label *ret_label) { 763 int ret = inet_pton(af, src, dst); 764 if (ret == 1) { 765 dfsan_set_label(dfsan_read_label(src, strlen(src) + 1), dst, 766 af == AF_INET ? sizeof(struct in_addr) : sizeof(in6_addr)); 767 } 768 *ret_label = 0; 769 return ret; 770 } 771 772 SANITIZER_INTERFACE_ATTRIBUTE 773 struct tm *__dfsw_localtime_r(const time_t *timep, struct tm *result, 774 dfsan_label timep_label, dfsan_label result_label, 775 dfsan_label *ret_label) { 776 struct tm *ret = localtime_r(timep, result); 777 if (ret) { 778 dfsan_set_label(dfsan_read_label(timep, sizeof(time_t)), result, 779 sizeof(struct tm)); 780 *ret_label = result_label; 781 } else { 782 *ret_label = 0; 783 } 784 return ret; 785 } 786 787 SANITIZER_INTERFACE_ATTRIBUTE 788 int __dfsw_getpwuid_r(id_t uid, struct passwd *pwd, 789 char *buf, size_t buflen, struct passwd **result, 790 dfsan_label uid_label, dfsan_label pwd_label, 791 dfsan_label buf_label, dfsan_label buflen_label, 792 dfsan_label result_label, dfsan_label *ret_label) { 793 // Store the data in pwd, the strings referenced from pwd in buf, and the 794 // address of pwd in *result. On failure, NULL is stored in *result. 795 int ret = getpwuid_r(uid, pwd, buf, buflen, result); 796 if (ret == 0) { 797 dfsan_set_label(0, pwd, sizeof(struct passwd)); 798 dfsan_set_label(0, buf, strlen(buf) + 1); 799 } 800 *ret_label = 0; 801 dfsan_set_label(0, result, sizeof(struct passwd*)); 802 return ret; 803 } 804 805 SANITIZER_INTERFACE_ATTRIBUTE 806 int __dfsw_epoll_wait(int epfd, struct epoll_event *events, int maxevents, 807 int timeout, dfsan_label epfd_label, 808 dfsan_label events_label, dfsan_label maxevents_label, 809 dfsan_label timeout_label, dfsan_label *ret_label) { 810 int ret = epoll_wait(epfd, events, maxevents, timeout); 811 if (ret > 0) 812 dfsan_set_label(0, events, ret * sizeof(*events)); 813 *ret_label = 0; 814 return ret; 815 } 816 817 SANITIZER_INTERFACE_ATTRIBUTE 818 int __dfsw_poll(struct pollfd *fds, nfds_t nfds, int timeout, 819 dfsan_label dfs_label, dfsan_label nfds_label, 820 dfsan_label timeout_label, dfsan_label *ret_label) { 821 int ret = poll(fds, nfds, timeout); 822 if (ret >= 0) { 823 for (; nfds > 0; --nfds) { 824 dfsan_set_label(0, &fds[nfds - 1].revents, sizeof(fds[nfds - 1].revents)); 825 } 826 } 827 *ret_label = 0; 828 return ret; 829 } 830 831 SANITIZER_INTERFACE_ATTRIBUTE 832 int __dfsw_select(int nfds, fd_set *readfds, fd_set *writefds, 833 fd_set *exceptfds, struct timeval *timeout, 834 dfsan_label nfds_label, dfsan_label readfds_label, 835 dfsan_label writefds_label, dfsan_label exceptfds_label, 836 dfsan_label timeout_label, dfsan_label *ret_label) { 837 int ret = select(nfds, readfds, writefds, exceptfds, timeout); 838 // Clear everything (also on error) since their content is either set or 839 // undefined. 840 if (readfds) { 841 dfsan_set_label(0, readfds, sizeof(fd_set)); 842 } 843 if (writefds) { 844 dfsan_set_label(0, writefds, sizeof(fd_set)); 845 } 846 if (exceptfds) { 847 dfsan_set_label(0, exceptfds, sizeof(fd_set)); 848 } 849 dfsan_set_label(0, timeout, sizeof(struct timeval)); 850 *ret_label = 0; 851 return ret; 852 } 853 854 SANITIZER_INTERFACE_ATTRIBUTE 855 int __dfsw_sched_getaffinity(pid_t pid, size_t cpusetsize, cpu_set_t *mask, 856 dfsan_label pid_label, 857 dfsan_label cpusetsize_label, 858 dfsan_label mask_label, dfsan_label *ret_label) { 859 int ret = sched_getaffinity(pid, cpusetsize, mask); 860 if (ret == 0) { 861 dfsan_set_label(0, mask, cpusetsize); 862 } 863 *ret_label = 0; 864 return ret; 865 } 866 867 SANITIZER_INTERFACE_ATTRIBUTE 868 int __dfsw_sigemptyset(sigset_t *set, dfsan_label set_label, 869 dfsan_label *ret_label) { 870 int ret = sigemptyset(set); 871 dfsan_set_label(0, set, sizeof(sigset_t)); 872 return ret; 873 } 874 875 class SignalHandlerScope { 876 public: 877 SignalHandlerScope() { 878 if (DFsanThread *t = GetCurrentThread()) 879 t->EnterSignalHandler(); 880 } 881 ~SignalHandlerScope() { 882 if (DFsanThread *t = GetCurrentThread()) 883 t->LeaveSignalHandler(); 884 } 885 }; 886 887 // Clear DFSan runtime TLS state at the end of a scope. 888 // 889 // Implementation must be async-signal-safe and use small data size, because 890 // instances of this class may live on the signal handler stack. 891 // 892 // DFSan uses TLS to pass metadata of arguments and return values. When an 893 // instrumented function accesses the TLS, if a signal callback happens, and the 894 // callback calls other instrumented functions with updating the same TLS, the 895 // TLS is in an inconsistent state after the callback ends. This may cause 896 // either under-tainting or over-tainting. 897 // 898 // The current implementation simply resets TLS at restore. This prevents from 899 // over-tainting. Although under-tainting may still happen, a taint flow can be 900 // found eventually if we run a DFSan-instrumented program multiple times. The 901 // alternative option is saving the entire TLS. However the TLS storage takes 902 // 2k bytes, and signal calls could be nested. So it does not seem worth. 903 class ScopedClearThreadLocalState { 904 public: 905 ScopedClearThreadLocalState() {} 906 ~ScopedClearThreadLocalState() { dfsan_clear_thread_local_state(); } 907 }; 908 909 // SignalSpinLocker::sigactions_mu guarantees atomicity of sigaction() calls. 910 const int kMaxSignals = 1024; 911 static atomic_uintptr_t sigactions[kMaxSignals]; 912 913 static void SignalHandler(int signo) { 914 SignalHandlerScope signal_handler_scope; 915 ScopedClearThreadLocalState scoped_clear_tls; 916 917 // Clear shadows for all inputs provided by system. This is why DFSan 918 // instrumentation generates a trampoline function to each function pointer, 919 // and uses the trampoline to clear shadows. However sigaction does not use 920 // a function pointer directly, so we have to do this manually. 921 dfsan_clear_arg_tls(0, sizeof(dfsan_label)); 922 923 typedef void (*signal_cb)(int x); 924 signal_cb cb = 925 (signal_cb)atomic_load(&sigactions[signo], memory_order_relaxed); 926 cb(signo); 927 } 928 929 static void SignalAction(int signo, siginfo_t *si, void *uc) { 930 SignalHandlerScope signal_handler_scope; 931 ScopedClearThreadLocalState scoped_clear_tls; 932 933 // Clear shadows for all inputs provided by system. Similar to SignalHandler. 934 dfsan_clear_arg_tls(0, 3 * sizeof(dfsan_label)); 935 dfsan_set_label(0, si, sizeof(*si)); 936 dfsan_set_label(0, uc, sizeof(ucontext_t)); 937 938 typedef void (*sigaction_cb)(int, siginfo_t *, void *); 939 sigaction_cb cb = 940 (sigaction_cb)atomic_load(&sigactions[signo], memory_order_relaxed); 941 cb(signo, si, uc); 942 } 943 944 SANITIZER_INTERFACE_ATTRIBUTE 945 int __dfsw_sigaction(int signum, const struct sigaction *act, 946 struct sigaction *oldact, dfsan_label signum_label, 947 dfsan_label act_label, dfsan_label oldact_label, 948 dfsan_label *ret_label) { 949 CHECK_LT(signum, kMaxSignals); 950 SignalSpinLocker lock; 951 uptr old_cb = atomic_load(&sigactions[signum], memory_order_relaxed); 952 struct sigaction new_act; 953 struct sigaction *pnew_act = act ? &new_act : nullptr; 954 if (act) { 955 internal_memcpy(pnew_act, act, sizeof(struct sigaction)); 956 if (pnew_act->sa_flags & SA_SIGINFO) { 957 uptr cb = (uptr)(pnew_act->sa_sigaction); 958 if (cb != (uptr)SIG_IGN && cb != (uptr)SIG_DFL) { 959 atomic_store(&sigactions[signum], cb, memory_order_relaxed); 960 pnew_act->sa_sigaction = SignalAction; 961 } 962 } else { 963 uptr cb = (uptr)(pnew_act->sa_handler); 964 if (cb != (uptr)SIG_IGN && cb != (uptr)SIG_DFL) { 965 atomic_store(&sigactions[signum], cb, memory_order_relaxed); 966 pnew_act->sa_handler = SignalHandler; 967 } 968 } 969 } 970 971 int ret = sigaction(signum, pnew_act, oldact); 972 973 if (ret == 0 && oldact) { 974 if (oldact->sa_flags & SA_SIGINFO) { 975 if (oldact->sa_sigaction == SignalAction) 976 oldact->sa_sigaction = (decltype(oldact->sa_sigaction))old_cb; 977 } else { 978 if (oldact->sa_handler == SignalHandler) 979 oldact->sa_handler = (decltype(oldact->sa_handler))old_cb; 980 } 981 } 982 983 if (oldact) { 984 dfsan_set_label(0, oldact, sizeof(struct sigaction)); 985 } 986 *ret_label = 0; 987 return ret; 988 } 989 990 SANITIZER_INTERFACE_ATTRIBUTE 991 sighandler_t __dfsw_signal(int signum, 992 void *(*handler_trampoline)(void *, int, dfsan_label, 993 dfsan_label *), 994 sighandler_t handler, dfsan_label signum_label, 995 dfsan_label handler_label, dfsan_label *ret_label) { 996 CHECK_LT(signum, kMaxSignals); 997 SignalSpinLocker lock; 998 uptr old_cb = atomic_load(&sigactions[signum], memory_order_relaxed); 999 if (handler != SIG_IGN && handler != SIG_DFL) { 1000 atomic_store(&sigactions[signum], (uptr)handler, memory_order_relaxed); 1001 handler = &SignalHandler; 1002 } 1003 1004 sighandler_t ret = signal(signum, handler); 1005 1006 if (ret == SignalHandler) 1007 ret = (sighandler_t)old_cb; 1008 1009 *ret_label = 0; 1010 return ret; 1011 } 1012 1013 SANITIZER_INTERFACE_ATTRIBUTE 1014 int __dfsw_sigaltstack(const stack_t *ss, stack_t *old_ss, dfsan_label ss_label, 1015 dfsan_label old_ss_label, dfsan_label *ret_label) { 1016 int ret = sigaltstack(ss, old_ss); 1017 if (ret != -1 && old_ss) 1018 dfsan_set_label(0, old_ss, sizeof(*old_ss)); 1019 *ret_label = 0; 1020 return ret; 1021 } 1022 1023 SANITIZER_INTERFACE_ATTRIBUTE 1024 int __dfsw_gettimeofday(struct timeval *tv, struct timezone *tz, 1025 dfsan_label tv_label, dfsan_label tz_label, 1026 dfsan_label *ret_label) { 1027 int ret = gettimeofday(tv, tz); 1028 if (tv) { 1029 dfsan_set_label(0, tv, sizeof(struct timeval)); 1030 } 1031 if (tz) { 1032 dfsan_set_label(0, tz, sizeof(struct timezone)); 1033 } 1034 *ret_label = 0; 1035 return ret; 1036 } 1037 1038 SANITIZER_INTERFACE_ATTRIBUTE void *__dfsw_memchr(void *s, int c, size_t n, 1039 dfsan_label s_label, 1040 dfsan_label c_label, 1041 dfsan_label n_label, 1042 dfsan_label *ret_label) { 1043 void *ret = memchr(s, c, n); 1044 if (flags().strict_data_dependencies) { 1045 *ret_label = ret ? s_label : 0; 1046 } else { 1047 size_t len = 1048 ret ? reinterpret_cast<char *>(ret) - reinterpret_cast<char *>(s) + 1 1049 : n; 1050 *ret_label = 1051 dfsan_union(dfsan_read_label(s, len), dfsan_union(s_label, c_label)); 1052 } 1053 return ret; 1054 } 1055 1056 SANITIZER_INTERFACE_ATTRIBUTE char *__dfsw_strrchr(char *s, int c, 1057 dfsan_label s_label, 1058 dfsan_label c_label, 1059 dfsan_label *ret_label) { 1060 char *ret = strrchr(s, c); 1061 if (flags().strict_data_dependencies) { 1062 *ret_label = ret ? s_label : 0; 1063 } else { 1064 *ret_label = 1065 dfsan_union(dfsan_read_label(s, strlen(s) + 1), 1066 dfsan_union(s_label, c_label)); 1067 } 1068 1069 return ret; 1070 } 1071 1072 SANITIZER_INTERFACE_ATTRIBUTE char *__dfsw_strstr(char *haystack, char *needle, 1073 dfsan_label haystack_label, 1074 dfsan_label needle_label, 1075 dfsan_label *ret_label) { 1076 char *ret = strstr(haystack, needle); 1077 if (flags().strict_data_dependencies) { 1078 *ret_label = ret ? haystack_label : 0; 1079 } else { 1080 size_t len = ret ? ret + strlen(needle) - haystack : strlen(haystack) + 1; 1081 *ret_label = 1082 dfsan_union(dfsan_read_label(haystack, len), 1083 dfsan_union(dfsan_read_label(needle, strlen(needle) + 1), 1084 dfsan_union(haystack_label, needle_label))); 1085 } 1086 1087 return ret; 1088 } 1089 1090 SANITIZER_INTERFACE_ATTRIBUTE int __dfsw_nanosleep(const struct timespec *req, 1091 struct timespec *rem, 1092 dfsan_label req_label, 1093 dfsan_label rem_label, 1094 dfsan_label *ret_label) { 1095 int ret = nanosleep(req, rem); 1096 *ret_label = 0; 1097 if (ret == -1) { 1098 // Interrupted by a signal, rem is filled with the remaining time. 1099 dfsan_set_label(0, rem, sizeof(struct timespec)); 1100 } 1101 return ret; 1102 } 1103 1104 static void clear_msghdr_labels(size_t bytes_written, struct msghdr *msg) { 1105 dfsan_set_label(0, msg, sizeof(*msg)); 1106 dfsan_set_label(0, msg->msg_name, msg->msg_namelen); 1107 dfsan_set_label(0, msg->msg_control, msg->msg_controllen); 1108 for (size_t i = 0; bytes_written > 0; ++i) { 1109 assert(i < msg->msg_iovlen); 1110 struct iovec *iov = &msg->msg_iov[i]; 1111 size_t iov_written = 1112 bytes_written < iov->iov_len ? bytes_written : iov->iov_len; 1113 dfsan_set_label(0, iov->iov_base, iov_written); 1114 bytes_written -= iov_written; 1115 } 1116 } 1117 1118 SANITIZER_INTERFACE_ATTRIBUTE int __dfsw_recvmmsg( 1119 int sockfd, struct mmsghdr *msgvec, unsigned int vlen, int flags, 1120 struct timespec *timeout, dfsan_label sockfd_label, 1121 dfsan_label msgvec_label, dfsan_label vlen_label, dfsan_label flags_label, 1122 dfsan_label timeout_label, dfsan_label *ret_label) { 1123 int ret = recvmmsg(sockfd, msgvec, vlen, flags, timeout); 1124 for (int i = 0; i < ret; ++i) { 1125 dfsan_set_label(0, &msgvec[i].msg_len, sizeof(msgvec[i].msg_len)); 1126 clear_msghdr_labels(msgvec[i].msg_len, &msgvec[i].msg_hdr); 1127 } 1128 *ret_label = 0; 1129 return ret; 1130 } 1131 1132 SANITIZER_INTERFACE_ATTRIBUTE ssize_t __dfsw_recvmsg( 1133 int sockfd, struct msghdr *msg, int flags, dfsan_label sockfd_label, 1134 dfsan_label msg_label, dfsan_label flags_label, dfsan_label *ret_label) { 1135 ssize_t ret = recvmsg(sockfd, msg, flags); 1136 if (ret >= 0) 1137 clear_msghdr_labels(ret, msg); 1138 *ret_label = 0; 1139 return ret; 1140 } 1141 1142 SANITIZER_INTERFACE_ATTRIBUTE int 1143 __dfsw_socketpair(int domain, int type, int protocol, int sv[2], 1144 dfsan_label domain_label, dfsan_label type_label, 1145 dfsan_label protocol_label, dfsan_label sv_label, 1146 dfsan_label *ret_label) { 1147 int ret = socketpair(domain, type, protocol, sv); 1148 *ret_label = 0; 1149 if (ret == 0) { 1150 dfsan_set_label(0, sv, sizeof(*sv) * 2); 1151 } 1152 return ret; 1153 } 1154 1155 SANITIZER_INTERFACE_ATTRIBUTE int __dfsw_getsockopt( 1156 int sockfd, int level, int optname, void *optval, socklen_t *optlen, 1157 dfsan_label sockfd_label, dfsan_label level_label, 1158 dfsan_label optname_label, dfsan_label optval_label, 1159 dfsan_label optlen_label, dfsan_label *ret_label) { 1160 int ret = getsockopt(sockfd, level, optname, optval, optlen); 1161 if (ret != -1 && optval && optlen) { 1162 dfsan_set_label(0, optlen, sizeof(*optlen)); 1163 dfsan_set_label(0, optval, *optlen); 1164 } 1165 *ret_label = 0; 1166 return ret; 1167 } 1168 1169 SANITIZER_INTERFACE_ATTRIBUTE int __dfsw_getsockname( 1170 int sockfd, struct sockaddr *addr, socklen_t *addrlen, 1171 dfsan_label sockfd_label, dfsan_label addr_label, dfsan_label addrlen_label, 1172 dfsan_label *ret_label) { 1173 socklen_t origlen = addrlen ? *addrlen : 0; 1174 int ret = getsockname(sockfd, addr, addrlen); 1175 if (ret != -1 && addr && addrlen) { 1176 socklen_t written_bytes = origlen < *addrlen ? origlen : *addrlen; 1177 dfsan_set_label(0, addrlen, sizeof(*addrlen)); 1178 dfsan_set_label(0, addr, written_bytes); 1179 } 1180 *ret_label = 0; 1181 return ret; 1182 } 1183 1184 SANITIZER_INTERFACE_ATTRIBUTE int __dfsw_getpeername( 1185 int sockfd, struct sockaddr *addr, socklen_t *addrlen, 1186 dfsan_label sockfd_label, dfsan_label addr_label, dfsan_label addrlen_label, 1187 dfsan_label *ret_label) { 1188 socklen_t origlen = addrlen ? *addrlen : 0; 1189 int ret = getpeername(sockfd, addr, addrlen); 1190 if (ret != -1 && addr && addrlen) { 1191 socklen_t written_bytes = origlen < *addrlen ? origlen : *addrlen; 1192 dfsan_set_label(0, addrlen, sizeof(*addrlen)); 1193 dfsan_set_label(0, addr, written_bytes); 1194 } 1195 *ret_label = 0; 1196 return ret; 1197 } 1198 1199 // Type of the trampoline function passed to the custom version of 1200 // dfsan_set_write_callback. 1201 typedef void (*write_trampoline_t)( 1202 void *callback, 1203 int fd, const void *buf, ssize_t count, 1204 dfsan_label fd_label, dfsan_label buf_label, dfsan_label count_label); 1205 1206 // Calls to dfsan_set_write_callback() set the values in this struct. 1207 // Calls to the custom version of write() read (and invoke) them. 1208 static struct { 1209 write_trampoline_t write_callback_trampoline = nullptr; 1210 void *write_callback = nullptr; 1211 } write_callback_info; 1212 1213 SANITIZER_INTERFACE_ATTRIBUTE void 1214 __dfsw_dfsan_set_write_callback( 1215 write_trampoline_t write_callback_trampoline, 1216 void *write_callback, 1217 dfsan_label write_callback_label, 1218 dfsan_label *ret_label) { 1219 write_callback_info.write_callback_trampoline = write_callback_trampoline; 1220 write_callback_info.write_callback = write_callback; 1221 } 1222 1223 SANITIZER_INTERFACE_ATTRIBUTE int 1224 __dfsw_write(int fd, const void *buf, size_t count, 1225 dfsan_label fd_label, dfsan_label buf_label, 1226 dfsan_label count_label, dfsan_label *ret_label) { 1227 if (write_callback_info.write_callback) { 1228 write_callback_info.write_callback_trampoline( 1229 write_callback_info.write_callback, 1230 fd, buf, count, 1231 fd_label, buf_label, count_label); 1232 } 1233 1234 *ret_label = 0; 1235 return write(fd, buf, count); 1236 } 1237 } // namespace __dfsan 1238 1239 // Type used to extract a dfsan_label with va_arg() 1240 typedef int dfsan_label_va; 1241 1242 // Formats a chunk either a constant string or a single format directive (e.g., 1243 // '%.3f'). 1244 struct Formatter { 1245 Formatter(char *str_, const char *fmt_, size_t size_) 1246 : str(str_), str_off(0), size(size_), fmt_start(fmt_), fmt_cur(fmt_), 1247 width(-1) {} 1248 1249 int format() { 1250 char *tmp_fmt = build_format_string(); 1251 int retval = 1252 snprintf(str + str_off, str_off < size ? size - str_off : 0, tmp_fmt, 1253 0 /* used only to avoid warnings */); 1254 free(tmp_fmt); 1255 return retval; 1256 } 1257 1258 template <typename T> int format(T arg) { 1259 char *tmp_fmt = build_format_string(); 1260 int retval; 1261 if (width >= 0) { 1262 retval = snprintf(str + str_off, str_off < size ? size - str_off : 0, 1263 tmp_fmt, width, arg); 1264 } else { 1265 retval = snprintf(str + str_off, str_off < size ? size - str_off : 0, 1266 tmp_fmt, arg); 1267 } 1268 free(tmp_fmt); 1269 return retval; 1270 } 1271 1272 char *build_format_string() { 1273 size_t fmt_size = fmt_cur - fmt_start + 1; 1274 char *new_fmt = (char *)malloc(fmt_size + 1); 1275 assert(new_fmt); 1276 internal_memcpy(new_fmt, fmt_start, fmt_size); 1277 new_fmt[fmt_size] = '\0'; 1278 return new_fmt; 1279 } 1280 1281 char *str_cur() { return str + str_off; } 1282 1283 size_t num_written_bytes(int retval) { 1284 if (retval < 0) { 1285 return 0; 1286 } 1287 1288 size_t num_avail = str_off < size ? size - str_off : 0; 1289 if (num_avail == 0) { 1290 return 0; 1291 } 1292 1293 size_t num_written = retval; 1294 // A return value of {v,}snprintf of size or more means that the output was 1295 // truncated. 1296 if (num_written >= num_avail) { 1297 num_written -= num_avail; 1298 } 1299 1300 return num_written; 1301 } 1302 1303 char *str; 1304 size_t str_off; 1305 size_t size; 1306 const char *fmt_start; 1307 const char *fmt_cur; 1308 int width; 1309 }; 1310 1311 // Formats the input and propagates the input labels to the output. The output 1312 // is stored in 'str'. 'size' bounds the number of output bytes. 'format' and 1313 // 'ap' are the format string and the list of arguments for formatting. Returns 1314 // the return value vsnprintf would return. 1315 // 1316 // The function tokenizes the format string in chunks representing either a 1317 // constant string or a single format directive (e.g., '%.3f') and formats each 1318 // chunk independently into the output string. This approach allows to figure 1319 // out which bytes of the output string depends on which argument and thus to 1320 // propagate labels more precisely. 1321 // 1322 // WARNING: This implementation does not support conversion specifiers with 1323 // positional arguments. 1324 static int format_buffer(char *str, size_t size, const char *fmt, 1325 dfsan_label *va_labels, dfsan_label *ret_label, 1326 va_list ap) { 1327 Formatter formatter(str, fmt, size); 1328 1329 while (*formatter.fmt_cur) { 1330 formatter.fmt_start = formatter.fmt_cur; 1331 formatter.width = -1; 1332 int retval = 0; 1333 1334 if (*formatter.fmt_cur != '%') { 1335 // Ordinary character. Consume all the characters until a '%' or the end 1336 // of the string. 1337 for (; *(formatter.fmt_cur + 1) && *(formatter.fmt_cur + 1) != '%'; 1338 ++formatter.fmt_cur) {} 1339 retval = formatter.format(); 1340 dfsan_set_label(0, formatter.str_cur(), 1341 formatter.num_written_bytes(retval)); 1342 } else { 1343 // Conversion directive. Consume all the characters until a conversion 1344 // specifier or the end of the string. 1345 bool end_fmt = false; 1346 for (; *formatter.fmt_cur && !end_fmt; ) { 1347 switch (*++formatter.fmt_cur) { 1348 case 'd': 1349 case 'i': 1350 case 'o': 1351 case 'u': 1352 case 'x': 1353 case 'X': 1354 switch (*(formatter.fmt_cur - 1)) { 1355 case 'h': 1356 // Also covers the 'hh' case (since the size of the arg is still 1357 // an int). 1358 retval = formatter.format(va_arg(ap, int)); 1359 break; 1360 case 'l': 1361 if (formatter.fmt_cur - formatter.fmt_start >= 2 && 1362 *(formatter.fmt_cur - 2) == 'l') { 1363 retval = formatter.format(va_arg(ap, long long int)); 1364 } else { 1365 retval = formatter.format(va_arg(ap, long int)); 1366 } 1367 break; 1368 case 'q': 1369 retval = formatter.format(va_arg(ap, long long int)); 1370 break; 1371 case 'j': 1372 retval = formatter.format(va_arg(ap, intmax_t)); 1373 break; 1374 case 'z': 1375 case 't': 1376 retval = formatter.format(va_arg(ap, size_t)); 1377 break; 1378 default: 1379 retval = formatter.format(va_arg(ap, int)); 1380 } 1381 dfsan_set_label(*va_labels++, formatter.str_cur(), 1382 formatter.num_written_bytes(retval)); 1383 end_fmt = true; 1384 break; 1385 1386 case 'a': 1387 case 'A': 1388 case 'e': 1389 case 'E': 1390 case 'f': 1391 case 'F': 1392 case 'g': 1393 case 'G': 1394 if (*(formatter.fmt_cur - 1) == 'L') { 1395 retval = formatter.format(va_arg(ap, long double)); 1396 } else { 1397 retval = formatter.format(va_arg(ap, double)); 1398 } 1399 dfsan_set_label(*va_labels++, formatter.str_cur(), 1400 formatter.num_written_bytes(retval)); 1401 end_fmt = true; 1402 break; 1403 1404 case 'c': 1405 retval = formatter.format(va_arg(ap, int)); 1406 dfsan_set_label(*va_labels++, formatter.str_cur(), 1407 formatter.num_written_bytes(retval)); 1408 end_fmt = true; 1409 break; 1410 1411 case 's': { 1412 char *arg = va_arg(ap, char *); 1413 retval = formatter.format(arg); 1414 va_labels++; 1415 internal_memcpy(shadow_for(formatter.str_cur()), shadow_for(arg), 1416 sizeof(dfsan_label) * 1417 formatter.num_written_bytes(retval)); 1418 end_fmt = true; 1419 break; 1420 } 1421 1422 case 'p': 1423 retval = formatter.format(va_arg(ap, void *)); 1424 dfsan_set_label(*va_labels++, formatter.str_cur(), 1425 formatter.num_written_bytes(retval)); 1426 end_fmt = true; 1427 break; 1428 1429 case 'n': { 1430 int *ptr = va_arg(ap, int *); 1431 *ptr = (int)formatter.str_off; 1432 va_labels++; 1433 dfsan_set_label(0, ptr, sizeof(ptr)); 1434 end_fmt = true; 1435 break; 1436 } 1437 1438 case '%': 1439 retval = formatter.format(); 1440 dfsan_set_label(0, formatter.str_cur(), 1441 formatter.num_written_bytes(retval)); 1442 end_fmt = true; 1443 break; 1444 1445 case '*': 1446 formatter.width = va_arg(ap, int); 1447 va_labels++; 1448 break; 1449 1450 default: 1451 break; 1452 } 1453 } 1454 } 1455 1456 if (retval < 0) { 1457 return retval; 1458 } 1459 1460 formatter.fmt_cur++; 1461 formatter.str_off += retval; 1462 } 1463 1464 *ret_label = 0; 1465 1466 // Number of bytes written in total. 1467 return formatter.str_off; 1468 } 1469 1470 extern "C" { 1471 SANITIZER_INTERFACE_ATTRIBUTE 1472 int __dfsw_sprintf(char *str, const char *format, dfsan_label str_label, 1473 dfsan_label format_label, dfsan_label *va_labels, 1474 dfsan_label *ret_label, ...) { 1475 va_list ap; 1476 va_start(ap, ret_label); 1477 int ret = format_buffer(str, ~0ul, format, va_labels, ret_label, ap); 1478 va_end(ap); 1479 return ret; 1480 } 1481 1482 SANITIZER_INTERFACE_ATTRIBUTE 1483 int __dfsw_snprintf(char *str, size_t size, const char *format, 1484 dfsan_label str_label, dfsan_label size_label, 1485 dfsan_label format_label, dfsan_label *va_labels, 1486 dfsan_label *ret_label, ...) { 1487 va_list ap; 1488 va_start(ap, ret_label); 1489 int ret = format_buffer(str, size, format, va_labels, ret_label, ap); 1490 va_end(ap); 1491 return ret; 1492 } 1493 1494 // Default empty implementations (weak). Users should redefine them. 1495 SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_trace_pc_guard, u32 *) {} 1496 SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_trace_pc_guard_init, u32 *, 1497 u32 *) {} 1498 SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_pcs_init, void) {} 1499 SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_trace_pc_indir, void) {} 1500 1501 SANITIZER_INTERFACE_WEAK_DEF(void, __dfsw___sanitizer_cov_trace_cmp, void) {} 1502 SANITIZER_INTERFACE_WEAK_DEF(void, __dfsw___sanitizer_cov_trace_cmp1, void) {} 1503 SANITIZER_INTERFACE_WEAK_DEF(void, __dfsw___sanitizer_cov_trace_cmp2, void) {} 1504 SANITIZER_INTERFACE_WEAK_DEF(void, __dfsw___sanitizer_cov_trace_cmp4, void) {} 1505 SANITIZER_INTERFACE_WEAK_DEF(void, __dfsw___sanitizer_cov_trace_cmp8, void) {} 1506 SANITIZER_INTERFACE_WEAK_DEF(void, __dfsw___sanitizer_cov_trace_const_cmp1, 1507 void) {} 1508 SANITIZER_INTERFACE_WEAK_DEF(void, __dfsw___sanitizer_cov_trace_const_cmp2, 1509 void) {} 1510 SANITIZER_INTERFACE_WEAK_DEF(void, __dfsw___sanitizer_cov_trace_const_cmp4, 1511 void) {} 1512 SANITIZER_INTERFACE_WEAK_DEF(void, __dfsw___sanitizer_cov_trace_const_cmp8, 1513 void) {} 1514 SANITIZER_INTERFACE_WEAK_DEF(void, __dfsw___sanitizer_cov_trace_switch, void) {} 1515 } // extern "C" 1516