contrib/llvm-project/compiler-rt/lib/dfsan/dfsan_custom.cc

   1 //===-- dfsan.cc ----------------------------------------------------------===//
   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 "sanitizer_common/sanitizer_common.h"
  15 #include "sanitizer_common/sanitizer_internal_defs.h"
  16 #include "sanitizer_common/sanitizer_linux.h"
  17
  18 #include "dfsan/dfsan.h"
  19
  20 #include <arpa/inet.h>
  21 #include <assert.h>
  22 #include <ctype.h>
  23 #include <dlfcn.h>
  24 #include <link.h>
  25 #include <poll.h>
  26 #include <pthread.h>
  27 #include <pwd.h>
  28 #include <sched.h>
  29 #include <signal.h>
  30 #include <stdarg.h>
  31 #include <stdint.h>
  32 #include <stdio.h>
  33 #include <stdlib.h>
  34 #include <string.h>
  35 #include <sys/resource.h>
  36 #include <sys/select.h>
  37 #include <sys/stat.h>
  38 #include <sys/time.h>
  39 #include <sys/types.h>
  40 #include <time.h>
  41 #include <unistd.h>
  42
  43 using namespace __dfsan;
  44
  45 #define CALL_WEAK_INTERCEPTOR_HOOK(f, ...)                                     \
  46   do {                                                                         \
  47     if (f)                                                                     \
  48       f(__VA_ARGS__);                                                          \
  49   } while (false)
  50 #define DECLARE_WEAK_INTERCEPTOR_HOOK(f, ...) \
  51 SANITIZER_INTERFACE_ATTRIBUTE SANITIZER_WEAK_ATTRIBUTE void f(__VA_ARGS__);
  52
  53 extern "C" {
  54 SANITIZER_INTERFACE_ATTRIBUTE int
  55 __dfsw_stat(const char *path, struct stat *buf, dfsan_label path_label,
  56             dfsan_label buf_label, dfsan_label *ret_label) {
  57   int ret = stat(path, buf);
  58   if (ret == 0)
  59     dfsan_set_label(0, buf, sizeof(struct stat));
  60   *ret_label = 0;
  61   return ret;
  62 }
  63
  64 SANITIZER_INTERFACE_ATTRIBUTE int __dfsw_fstat(int fd, struct stat *buf,
  65                                                dfsan_label fd_label,
  66                                                dfsan_label buf_label,
  67                                                dfsan_label *ret_label) {
  68   int ret = fstat(fd, buf);
  69   if (ret == 0)
  70     dfsan_set_label(0, buf, sizeof(struct stat));
  71   *ret_label = 0;
  72   return ret;
  73 }
  74
  75 SANITIZER_INTERFACE_ATTRIBUTE char *__dfsw_strchr(const char *s, int c,
  76                                                   dfsan_label s_label,
  77                                                   dfsan_label c_label,
  78                                                   dfsan_label *ret_label) {
  79   for (size_t i = 0;; ++i) {
  80     if (s[i] == c || s[i] == 0) {
  81       if (flags().strict_data_dependencies) {
  82         *ret_label = s_label;
  83       } else {
  84         *ret_label = dfsan_union(dfsan_read_label(s, i + 1),
  85                                  dfsan_union(s_label, c_label));
  86       }
  87       return s[i] == 0 ? nullptr : const_cast<char *>(s+i);
  88     }
  89   }
  90 }
  91
  92 DECLARE_WEAK_INTERCEPTOR_HOOK(dfsan_weak_hook_memcmp, uptr caller_pc,
  93                               const void *s1, const void *s2, size_t n,
  94                               dfsan_label s1_label, dfsan_label s2_label,
  95                               dfsan_label n_label)
  96
  97 SANITIZER_INTERFACE_ATTRIBUTE int __dfsw_memcmp(const void *s1, const void *s2,
  98                                                 size_t n, dfsan_label s1_label,
  99                                                 dfsan_label s2_label,
 100                                                 dfsan_label n_label,
 101                                                 dfsan_label *ret_label) {
 102   CALL_WEAK_INTERCEPTOR_HOOK(dfsan_weak_hook_memcmp, GET_CALLER_PC(), s1, s2, n,
 103                              s1_label, s2_label, n_label);
 104   const char *cs1 = (const char *) s1, *cs2 = (const char *) s2;
 105   for (size_t i = 0; i != n; ++i) {
 106     if (cs1[i] != cs2[i]) {
 107       if (flags().strict_data_dependencies) {
 108         *ret_label = 0;
 109       } else {
 110         *ret_label = dfsan_union(dfsan_read_label(cs1, i + 1),
 111                                  dfsan_read_label(cs2, i + 1));
 112       }
 113       return cs1[i] - cs2[i];
 114     }
 115   }
 116
 117   if (flags().strict_data_dependencies) {
 118     *ret_label = 0;
 119   } else {
 120     *ret_label = dfsan_union(dfsan_read_label(cs1, n),
 121                              dfsan_read_label(cs2, n));
 122   }
 123   return 0;
 124 }
 125
 126 DECLARE_WEAK_INTERCEPTOR_HOOK(dfsan_weak_hook_strcmp, uptr caller_pc,
 127                               const char *s1, const char *s2,
 128                               dfsan_label s1_label, dfsan_label s2_label)
 129
 130 SANITIZER_INTERFACE_ATTRIBUTE int __dfsw_strcmp(const char *s1, const char *s2,
 131                                                 dfsan_label s1_label,
 132                                                 dfsan_label s2_label,
 133                                                 dfsan_label *ret_label) {
 134   CALL_WEAK_INTERCEPTOR_HOOK(dfsan_weak_hook_strcmp, GET_CALLER_PC(), s1, s2,
 135                              s1_label, s2_label);
 136   for (size_t i = 0;; ++i) {
 137     if (s1[i] != s2[i] || s1[i] == 0 || s2[i] == 0) {
 138       if (flags().strict_data_dependencies) {
 139         *ret_label = 0;
 140       } else {
 141         *ret_label = dfsan_union(dfsan_read_label(s1, i + 1),
 142                                  dfsan_read_label(s2, i + 1));
 143       }
 144       return s1[i] - s2[i];
 145     }
 146   }
 147   return 0;
 148 }
 149
 150 SANITIZER_INTERFACE_ATTRIBUTE int
 151 __dfsw_strcasecmp(const char *s1, const char *s2, dfsan_label s1_label,
 152                   dfsan_label s2_label, dfsan_label *ret_label) {
 153   for (size_t i = 0;; ++i) {
 154     if (tolower(s1[i]) != tolower(s2[i]) || s1[i] == 0 || s2[i] == 0) {
 155       if (flags().strict_data_dependencies) {
 156         *ret_label = 0;
 157       } else {
 158         *ret_label = dfsan_union(dfsan_read_label(s1, i + 1),
 159                                  dfsan_read_label(s2, i + 1));
 160       }
 161       return s1[i] - s2[i];
 162     }
 163   }
 164   return 0;
 165 }
 166
 167 DECLARE_WEAK_INTERCEPTOR_HOOK(dfsan_weak_hook_strncmp, uptr caller_pc,
 168                               const char *s1, const char *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_strncmp(const char *s1, const char *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   if (n == 0) {
 178     *ret_label = 0;
 179     return 0;
 180   }
 181
 182   CALL_WEAK_INTERCEPTOR_HOOK(dfsan_weak_hook_strncmp, GET_CALLER_PC(), s1, s2,
 183                              n, s1_label, s2_label, n_label);
 184
 185   for (size_t i = 0;; ++i) {
 186     if (s1[i] != s2[i] || s1[i] == 0 || s2[i] == 0 || i == n - 1) {
 187       if (flags().strict_data_dependencies) {
 188         *ret_label = 0;
 189       } else {
 190         *ret_label = dfsan_union(dfsan_read_label(s1, i + 1),
 191                                  dfsan_read_label(s2, i + 1));
 192       }
 193       return s1[i] - s2[i];
 194     }
 195   }
 196   return 0;
 197 }
 198
 199 SANITIZER_INTERFACE_ATTRIBUTE int
 200 __dfsw_strncasecmp(const char *s1, const char *s2, size_t n,
 201                    dfsan_label s1_label, dfsan_label s2_label,
 202                    dfsan_label n_label, dfsan_label *ret_label) {
 203   if (n == 0) {
 204     *ret_label = 0;
 205     return 0;
 206   }
 207
 208   for (size_t i = 0;; ++i) {
 209     if (tolower(s1[i]) != tolower(s2[i]) || s1[i] == 0 || s2[i] == 0 ||
 210         i == n - 1) {
 211       if (flags().strict_data_dependencies) {
 212         *ret_label = 0;
 213       } else {
 214         *ret_label = dfsan_union(dfsan_read_label(s1, i + 1),
 215                                  dfsan_read_label(s2, i + 1));
 216       }
 217       return s1[i] - s2[i];
 218     }
 219   }
 220   return 0;
 221 }
 222
 223 SANITIZER_INTERFACE_ATTRIBUTE void *__dfsw_calloc(size_t nmemb, size_t size,
 224                                                   dfsan_label nmemb_label,
 225                                                   dfsan_label size_label,
 226                                                   dfsan_label *ret_label) {
 227   void *p = calloc(nmemb, size);
 228   dfsan_set_label(0, p, nmemb * size);
 229   *ret_label = 0;
 230   return p;
 231 }
 232
 233 SANITIZER_INTERFACE_ATTRIBUTE size_t
 234 __dfsw_strlen(const char *s, dfsan_label s_label, dfsan_label *ret_label) {
 235   size_t ret = strlen(s);
 236   if (flags().strict_data_dependencies) {
 237     *ret_label = 0;
 238   } else {
 239     *ret_label = dfsan_read_label(s, ret + 1);
 240   }
 241   return ret;
 242 }
 243
 244
 245 static void *dfsan_memcpy(void *dest, const void *src, size_t n) {
 246   dfsan_label *sdest = shadow_for(dest);
 247   const dfsan_label *ssrc = shadow_for(src);
 248   internal_memcpy((void *)sdest, (const void *)ssrc, n * sizeof(dfsan_label));
 249   return internal_memcpy(dest, src, n);
 250 }
 251
 252 static void dfsan_memset(void *s, int c, dfsan_label c_label, size_t n) {
 253   internal_memset(s, c, n);
 254   dfsan_set_label(c_label, s, n);
 255 }
 256
 257 SANITIZER_INTERFACE_ATTRIBUTE
 258 void *__dfsw_memcpy(void *dest, const void *src, size_t n,
 259                     dfsan_label dest_label, dfsan_label src_label,
 260                     dfsan_label n_label, dfsan_label *ret_label) {
 261   *ret_label = dest_label;
 262   return dfsan_memcpy(dest, src, n);
 263 }
 264
 265 SANITIZER_INTERFACE_ATTRIBUTE
 266 void *__dfsw_memset(void *s, int c, size_t n,
 267                     dfsan_label s_label, dfsan_label c_label,
 268                     dfsan_label n_label, dfsan_label *ret_label) {
 269   dfsan_memset(s, c, c_label, n);
 270   *ret_label = s_label;
 271   return s;
 272 }
 273
 274 SANITIZER_INTERFACE_ATTRIBUTE char *
 275 __dfsw_strdup(const char *s, dfsan_label s_label, dfsan_label *ret_label) {
 276   size_t len = strlen(s);
 277   void *p = malloc(len+1);
 278   dfsan_memcpy(p, s, len+1);
 279   *ret_label = 0;
 280   return static_cast<char *>(p);
 281 }
 282
 283 SANITIZER_INTERFACE_ATTRIBUTE char *
 284 __dfsw_strncpy(char *s1, const char *s2, size_t n, dfsan_label s1_label,
 285                dfsan_label s2_label, dfsan_label n_label,
 286                dfsan_label *ret_label) {
 287   size_t len = strlen(s2);
 288   if (len < n) {
 289     dfsan_memcpy(s1, s2, len+1);
 290     dfsan_memset(s1+len+1, 0, 0, n-len-1);
 291   } else {
 292     dfsan_memcpy(s1, s2, n);
 293   }
 294
 295   *ret_label = s1_label;
 296   return s1;
 297 }
 298
 299 SANITIZER_INTERFACE_ATTRIBUTE ssize_t
 300 __dfsw_pread(int fd, void *buf, size_t count, off_t offset,
 301              dfsan_label fd_label, dfsan_label buf_label,
 302              dfsan_label count_label, dfsan_label offset_label,
 303              dfsan_label *ret_label) {
 304   ssize_t ret = pread(fd, buf, count, offset);
 305   if (ret > 0)
 306     dfsan_set_label(0, buf, ret);
 307   *ret_label = 0;
 308   return ret;
 309 }
 310
 311 SANITIZER_INTERFACE_ATTRIBUTE ssize_t
 312 __dfsw_read(int fd, void *buf, size_t count,
 313              dfsan_label fd_label, dfsan_label buf_label,
 314              dfsan_label count_label,
 315              dfsan_label *ret_label) {
 316   ssize_t ret = read(fd, buf, count);
 317   if (ret > 0)
 318     dfsan_set_label(0, buf, ret);
 319   *ret_label = 0;
 320   return ret;
 321 }
 322
 323 SANITIZER_INTERFACE_ATTRIBUTE int __dfsw_clock_gettime(clockid_t clk_id,
 324                                                        struct timespec *tp,
 325                                                        dfsan_label clk_id_label,
 326                                                        dfsan_label tp_label,
 327                                                        dfsan_label *ret_label) {
 328   int ret = clock_gettime(clk_id, tp);
 329   if (ret == 0)
 330     dfsan_set_label(0, tp, sizeof(struct timespec));
 331   *ret_label = 0;
 332   return ret;
 333 }
 334
 335 static void unpoison(const void *ptr, uptr size) {
 336   dfsan_set_label(0, const_cast<void *>(ptr), size);
 337 }
 338
 339 // dlopen() ultimately calls mmap() down inside the loader, which generally
 340 // doesn't participate in dynamic symbol resolution.  Therefore we won't
 341 // intercept its calls to mmap, and we have to hook it here.
 342 SANITIZER_INTERFACE_ATTRIBUTE void *
 343 __dfsw_dlopen(const char *filename, int flag, dfsan_label filename_label,
 344               dfsan_label flag_label, dfsan_label *ret_label) {
 345   void *handle = dlopen(filename, flag);
 346   link_map *map = GET_LINK_MAP_BY_DLOPEN_HANDLE(handle);
 347   if (map)
 348     ForEachMappedRegion(map, unpoison);
 349   *ret_label = 0;
 350   return handle;
 351 }
 352
 353 struct pthread_create_info {
 354   void *(*start_routine_trampoline)(void *, void *, dfsan_label, dfsan_label *);
 355   void *start_routine;
 356   void *arg;
 357 };
 358
 359 static void *pthread_create_cb(void *p) {
 360   pthread_create_info pci(*(pthread_create_info *)p);
 361   free(p);
 362   dfsan_label ret_label;
 363   return pci.start_routine_trampoline(pci.start_routine, pci.arg, 0,
 364                                       &ret_label);
 365 }
 366
 367 SANITIZER_INTERFACE_ATTRIBUTE int __dfsw_pthread_create(
 368     pthread_t *thread, const pthread_attr_t *attr,
 369     void *(*start_routine_trampoline)(void *, void *, dfsan_label,
 370                                       dfsan_label *),
 371     void *start_routine, void *arg, dfsan_label thread_label,
 372     dfsan_label attr_label, dfsan_label start_routine_label,
 373     dfsan_label arg_label, dfsan_label *ret_label) {
 374   pthread_create_info *pci =
 375       (pthread_create_info *)malloc(sizeof(pthread_create_info));
 376   pci->start_routine_trampoline = start_routine_trampoline;
 377   pci->start_routine = start_routine;
 378   pci->arg = arg;
 379   int rv = pthread_create(thread, attr, pthread_create_cb, (void *)pci);
 380   if (rv != 0)
 381     free(pci);
 382   *ret_label = 0;
 383   return rv;
 384 }
 385
 386 struct dl_iterate_phdr_info {
 387   int (*callback_trampoline)(void *callback, struct dl_phdr_info *info,
 388                              size_t size, void *data, dfsan_label info_label,
 389                              dfsan_label size_label, dfsan_label data_label,
 390                              dfsan_label *ret_label);
 391   void *callback;
 392   void *data;
 393 };
 394
 395 int dl_iterate_phdr_cb(struct dl_phdr_info *info, size_t size, void *data) {
 396   dl_iterate_phdr_info *dipi = (dl_iterate_phdr_info *)data;
 397   dfsan_set_label(0, *info);
 398   dfsan_set_label(0, const_cast<char *>(info->dlpi_name),
 399                   strlen(info->dlpi_name) + 1);
 400   dfsan_set_label(
 401       0, const_cast<char *>(reinterpret_cast<const char *>(info->dlpi_phdr)),
 402       sizeof(*info->dlpi_phdr) * info->dlpi_phnum);
 403   dfsan_label ret_label;
 404   return dipi->callback_trampoline(dipi->callback, info, size, dipi->data, 0, 0,
 405                                    0, &ret_label);
 406 }
 407
 408 SANITIZER_INTERFACE_ATTRIBUTE int __dfsw_dl_iterate_phdr(
 409     int (*callback_trampoline)(void *callback, struct dl_phdr_info *info,
 410                                size_t size, void *data, dfsan_label info_label,
 411                                dfsan_label size_label, dfsan_label data_label,
 412                                dfsan_label *ret_label),
 413     void *callback, void *data, dfsan_label callback_label,
 414     dfsan_label data_label, dfsan_label *ret_label) {
 415   dl_iterate_phdr_info dipi = { callback_trampoline, callback, data };
 416   *ret_label = 0;
 417   return dl_iterate_phdr(dl_iterate_phdr_cb, &dipi);
 418 }
 419
 420 SANITIZER_INTERFACE_ATTRIBUTE
 421 char *__dfsw_ctime_r(const time_t *timep, char *buf, dfsan_label timep_label,
 422                      dfsan_label buf_label, dfsan_label *ret_label) {
 423   char *ret = ctime_r(timep, buf);
 424   if (ret) {
 425     dfsan_set_label(dfsan_read_label(timep, sizeof(time_t)), buf,
 426                     strlen(buf) + 1);
 427     *ret_label = buf_label;
 428   } else {
 429     *ret_label = 0;
 430   }
 431   return ret;
 432 }
 433
 434 SANITIZER_INTERFACE_ATTRIBUTE
 435 char *__dfsw_fgets(char *s, int size, FILE *stream, dfsan_label s_label,
 436                    dfsan_label size_label, dfsan_label stream_label,
 437                    dfsan_label *ret_label) {
 438   char *ret = fgets(s, size, stream);
 439   if (ret) {
 440     dfsan_set_label(0, ret, strlen(ret) + 1);
 441     *ret_label = s_label;
 442   } else {
 443     *ret_label = 0;
 444   }
 445   return ret;
 446 }
 447
 448 SANITIZER_INTERFACE_ATTRIBUTE
 449 char *__dfsw_getcwd(char *buf, size_t size, dfsan_label buf_label,
 450                     dfsan_label size_label, dfsan_label *ret_label) {
 451   char *ret = getcwd(buf, size);
 452   if (ret) {
 453     dfsan_set_label(0, ret, strlen(ret) + 1);
 454     *ret_label = buf_label;
 455   } else {
 456     *ret_label = 0;
 457   }
 458   return ret;
 459 }
 460
 461 SANITIZER_INTERFACE_ATTRIBUTE
 462 char *__dfsw_get_current_dir_name(dfsan_label *ret_label) {
 463   char *ret = get_current_dir_name();
 464   if (ret) {
 465     dfsan_set_label(0, ret, strlen(ret) + 1);
 466   }
 467   *ret_label = 0;
 468   return ret;
 469 }
 470
 471 SANITIZER_INTERFACE_ATTRIBUTE
 472 int __dfsw_gethostname(char *name, size_t len, dfsan_label name_label,
 473                        dfsan_label len_label, dfsan_label *ret_label) {
 474   int ret = gethostname(name, len);
 475   if (ret == 0) {
 476     dfsan_set_label(0, name, strlen(name) + 1);
 477   }
 478   *ret_label = 0;
 479   return ret;
 480 }
 481
 482 SANITIZER_INTERFACE_ATTRIBUTE
 483 int __dfsw_getrlimit(int resource, struct rlimit *rlim,
 484                      dfsan_label resource_label, dfsan_label rlim_label,
 485                      dfsan_label *ret_label) {
 486   int ret = getrlimit(resource, rlim);
 487   if (ret == 0) {
 488     dfsan_set_label(0, rlim, sizeof(struct rlimit));
 489   }
 490   *ret_label = 0;
 491   return ret;
 492 }
 493
 494 SANITIZER_INTERFACE_ATTRIBUTE
 495 int __dfsw_getrusage(int who, struct rusage *usage, dfsan_label who_label,
 496                      dfsan_label usage_label, dfsan_label *ret_label) {
 497   int ret = getrusage(who, usage);
 498   if (ret == 0) {
 499     dfsan_set_label(0, usage, sizeof(struct rusage));
 500   }
 501   *ret_label = 0;
 502   return ret;
 503 }
 504
 505 SANITIZER_INTERFACE_ATTRIBUTE
 506 char *__dfsw_strcpy(char *dest, const char *src, dfsan_label dst_label,
 507                     dfsan_label src_label, dfsan_label *ret_label) {
 508   char *ret = strcpy(dest, src);
 509   if (ret) {
 510     internal_memcpy(shadow_for(dest), shadow_for(src),
 511                     sizeof(dfsan_label) * (strlen(src) + 1));
 512   }
 513   *ret_label = dst_label;
 514   return ret;
 515 }
 516
 517 SANITIZER_INTERFACE_ATTRIBUTE
 518 long int __dfsw_strtol(const char *nptr, char **endptr, int base,
 519                        dfsan_label nptr_label, dfsan_label endptr_label,
 520                        dfsan_label base_label, dfsan_label *ret_label) {
 521   char *tmp_endptr;
 522   long int ret = strtol(nptr, &tmp_endptr, base);
 523   if (endptr) {
 524     *endptr = tmp_endptr;
 525   }
 526   if (tmp_endptr > nptr) {
 527     // If *tmp_endptr is '\0' include its label as well.
 528     *ret_label = dfsan_union(
 529         base_label,
 530         dfsan_read_label(nptr, tmp_endptr - nptr + (*tmp_endptr ? 0 : 1)));
 531   } else {
 532     *ret_label = 0;
 533   }
 534   return ret;
 535 }
 536
 537 SANITIZER_INTERFACE_ATTRIBUTE
 538 double __dfsw_strtod(const char *nptr, char **endptr,
 539                        dfsan_label nptr_label, dfsan_label endptr_label,
 540                        dfsan_label *ret_label) {
 541   char *tmp_endptr;
 542   double ret = strtod(nptr, &tmp_endptr);
 543   if (endptr) {
 544     *endptr = tmp_endptr;
 545   }
 546   if (tmp_endptr > nptr) {
 547     // If *tmp_endptr is '\0' include its label as well.
 548     *ret_label = dfsan_read_label(
 549         nptr,
 550         tmp_endptr - nptr + (*tmp_endptr ? 0 : 1));
 551   } else {
 552     *ret_label = 0;
 553   }
 554   return ret;
 555 }
 556
 557 SANITIZER_INTERFACE_ATTRIBUTE
 558 long long int __dfsw_strtoll(const char *nptr, char **endptr, int base,
 559                        dfsan_label nptr_label, dfsan_label endptr_label,
 560                        dfsan_label base_label, dfsan_label *ret_label) {
 561   char *tmp_endptr;
 562   long long int ret = strtoll(nptr, &tmp_endptr, base);
 563   if (endptr) {
 564     *endptr = tmp_endptr;
 565   }
 566   if (tmp_endptr > nptr) {
 567     // If *tmp_endptr is '\0' include its label as well.
 568     *ret_label = dfsan_union(
 569         base_label,
 570         dfsan_read_label(nptr, tmp_endptr - nptr + (*tmp_endptr ? 0 : 1)));
 571   } else {
 572     *ret_label = 0;
 573   }
 574   return ret;
 575 }
 576
 577 SANITIZER_INTERFACE_ATTRIBUTE
 578 unsigned long int __dfsw_strtoul(const char *nptr, char **endptr, int base,
 579                        dfsan_label nptr_label, dfsan_label endptr_label,
 580                        dfsan_label base_label, dfsan_label *ret_label) {
 581   char *tmp_endptr;
 582   unsigned long int ret = strtoul(nptr, &tmp_endptr, base);
 583   if (endptr) {
 584     *endptr = tmp_endptr;
 585   }
 586   if (tmp_endptr > nptr) {
 587     // If *tmp_endptr is '\0' include its label as well.
 588     *ret_label = dfsan_union(
 589         base_label,
 590         dfsan_read_label(nptr, tmp_endptr - nptr + (*tmp_endptr ? 0 : 1)));
 591   } else {
 592     *ret_label = 0;
 593   }
 594   return ret;
 595 }
 596
 597 SANITIZER_INTERFACE_ATTRIBUTE
 598 long long unsigned int __dfsw_strtoull(const char *nptr, char **endptr,
 599                                        dfsan_label nptr_label,
 600                                        int base, dfsan_label endptr_label,
 601                                        dfsan_label base_label,
 602                                        dfsan_label *ret_label) {
 603   char *tmp_endptr;
 604   long long unsigned int ret = strtoull(nptr, &tmp_endptr, base);
 605   if (endptr) {
 606     *endptr = tmp_endptr;
 607   }
 608   if (tmp_endptr > nptr) {
 609     // If *tmp_endptr is '\0' include its label as well.
 610     *ret_label = dfsan_union(
 611         base_label,
 612         dfsan_read_label(nptr, tmp_endptr - nptr + (*tmp_endptr ? 0 : 1)));
 613   } else {
 614     *ret_label = 0;
 615   }
 616   return ret;
 617 }
 618
 619 SANITIZER_INTERFACE_ATTRIBUTE
 620 time_t __dfsw_time(time_t *t, dfsan_label t_label, dfsan_label *ret_label) {
 621   time_t ret = time(t);
 622   if (ret != (time_t) -1 && t) {
 623     dfsan_set_label(0, t, sizeof(time_t));
 624   }
 625   *ret_label = 0;
 626   return ret;
 627 }
 628
 629 SANITIZER_INTERFACE_ATTRIBUTE
 630 int __dfsw_inet_pton(int af, const char *src, void *dst, dfsan_label af_label,
 631                      dfsan_label src_label, dfsan_label dst_label,
 632                      dfsan_label *ret_label) {
 633   int ret = inet_pton(af, src, dst);
 634   if (ret == 1) {
 635     dfsan_set_label(dfsan_read_label(src, strlen(src) + 1), dst,
 636                     af == AF_INET ? sizeof(struct in_addr) : sizeof(in6_addr));
 637   }
 638   *ret_label = 0;
 639   return ret;
 640 }
 641
 642 SANITIZER_INTERFACE_ATTRIBUTE
 643 struct tm *__dfsw_localtime_r(const time_t *timep, struct tm *result,
 644                               dfsan_label timep_label, dfsan_label result_label,
 645                               dfsan_label *ret_label) {
 646   struct tm *ret = localtime_r(timep, result);
 647   if (ret) {
 648     dfsan_set_label(dfsan_read_label(timep, sizeof(time_t)), result,
 649                     sizeof(struct tm));
 650     *ret_label = result_label;
 651   } else {
 652     *ret_label = 0;
 653   }
 654   return ret;
 655 }
 656
 657 SANITIZER_INTERFACE_ATTRIBUTE
 658 int __dfsw_getpwuid_r(id_t uid, struct passwd *pwd,
 659                       char *buf, size_t buflen, struct passwd **result,
 660                       dfsan_label uid_label, dfsan_label pwd_label,
 661                       dfsan_label buf_label, dfsan_label buflen_label,
 662                       dfsan_label result_label, dfsan_label *ret_label) {
 663   // Store the data in pwd, the strings referenced from pwd in buf, and the
 664   // address of pwd in *result.  On failure, NULL is stored in *result.
 665   int ret = getpwuid_r(uid, pwd, buf, buflen, result);
 666   if (ret == 0) {
 667     dfsan_set_label(0, pwd, sizeof(struct passwd));
 668     dfsan_set_label(0, buf, strlen(buf) + 1);
 669   }
 670   *ret_label = 0;
 671   dfsan_set_label(0, result, sizeof(struct passwd*));
 672   return ret;
 673 }
 674
 675 SANITIZER_INTERFACE_ATTRIBUTE
 676 int __dfsw_poll(struct pollfd *fds, nfds_t nfds, int timeout,
 677                 dfsan_label dfs_label, dfsan_label nfds_label,
 678                 dfsan_label timeout_label, dfsan_label *ret_label) {
 679   int ret = poll(fds, nfds, timeout);
 680   if (ret >= 0) {
 681     for (; nfds > 0; --nfds) {
 682       dfsan_set_label(0, &fds[nfds - 1].revents, sizeof(fds[nfds - 1].revents));
 683     }
 684   }
 685   *ret_label = 0;
 686   return ret;
 687 }
 688
 689 SANITIZER_INTERFACE_ATTRIBUTE
 690 int __dfsw_select(int nfds, fd_set *readfds, fd_set *writefds,
 691                   fd_set *exceptfds, struct timeval *timeout,
 692                   dfsan_label nfds_label, dfsan_label readfds_label,
 693                   dfsan_label writefds_label, dfsan_label exceptfds_label,
 694                   dfsan_label timeout_label, dfsan_label *ret_label) {
 695   int ret = select(nfds, readfds, writefds, exceptfds, timeout);
 696   // Clear everything (also on error) since their content is either set or
 697   // undefined.
 698   if (readfds) {
 699     dfsan_set_label(0, readfds, sizeof(fd_set));
 700   }
 701   if (writefds) {
 702     dfsan_set_label(0, writefds, sizeof(fd_set));
 703   }
 704   if (exceptfds) {
 705     dfsan_set_label(0, exceptfds, sizeof(fd_set));
 706   }
 707   dfsan_set_label(0, timeout, sizeof(struct timeval));
 708   *ret_label = 0;
 709   return ret;
 710 }
 711
 712 SANITIZER_INTERFACE_ATTRIBUTE
 713 int __dfsw_sched_getaffinity(pid_t pid, size_t cpusetsize, cpu_set_t *mask,
 714                              dfsan_label pid_label,
 715                              dfsan_label cpusetsize_label,
 716                              dfsan_label mask_label, dfsan_label *ret_label) {
 717   int ret = sched_getaffinity(pid, cpusetsize, mask);
 718   if (ret == 0) {
 719     dfsan_set_label(0, mask, cpusetsize);
 720   }
 721   *ret_label = 0;
 722   return ret;
 723 }
 724
 725 SANITIZER_INTERFACE_ATTRIBUTE
 726 int __dfsw_sigemptyset(sigset_t *set, dfsan_label set_label,
 727                        dfsan_label *ret_label) {
 728   int ret = sigemptyset(set);
 729   dfsan_set_label(0, set, sizeof(sigset_t));
 730   return ret;
 731 }
 732
 733 SANITIZER_INTERFACE_ATTRIBUTE
 734 int __dfsw_sigaction(int signum, const struct sigaction *act,
 735                      struct sigaction *oldact, dfsan_label signum_label,
 736                      dfsan_label act_label, dfsan_label oldact_label,
 737                      dfsan_label *ret_label) {
 738   int ret = sigaction(signum, act, oldact);
 739   if (oldact) {
 740     dfsan_set_label(0, oldact, sizeof(struct sigaction));
 741   }
 742   *ret_label = 0;
 743   return ret;
 744 }
 745
 746 SANITIZER_INTERFACE_ATTRIBUTE
 747 int __dfsw_gettimeofday(struct timeval *tv, struct timezone *tz,
 748                         dfsan_label tv_label, dfsan_label tz_label,
 749                         dfsan_label *ret_label) {
 750   int ret = gettimeofday(tv, tz);
 751   if (tv) {
 752     dfsan_set_label(0, tv, sizeof(struct timeval));
 753   }
 754   if (tz) {
 755     dfsan_set_label(0, tz, sizeof(struct timezone));
 756   }
 757   *ret_label = 0;
 758   return ret;
 759 }
 760
 761 SANITIZER_INTERFACE_ATTRIBUTE void *__dfsw_memchr(void *s, int c, size_t n,
 762                                                   dfsan_label s_label,
 763                                                   dfsan_label c_label,
 764                                                   dfsan_label n_label,
 765                                                   dfsan_label *ret_label) {
 766   void *ret = memchr(s, c, n);
 767   if (flags().strict_data_dependencies) {
 768     *ret_label = ret ? s_label : 0;
 769   } else {
 770     size_t len =
 771         ret ? reinterpret_cast<char *>(ret) - reinterpret_cast<char *>(s) + 1
 772             : n;
 773     *ret_label =
 774         dfsan_union(dfsan_read_label(s, len), dfsan_union(s_label, c_label));
 775   }
 776   return ret;
 777 }
 778
 779 SANITIZER_INTERFACE_ATTRIBUTE char *__dfsw_strrchr(char *s, int c,
 780                                                    dfsan_label s_label,
 781                                                    dfsan_label c_label,
 782                                                    dfsan_label *ret_label) {
 783   char *ret = strrchr(s, c);
 784   if (flags().strict_data_dependencies) {
 785     *ret_label = ret ? s_label : 0;
 786   } else {
 787     *ret_label =
 788         dfsan_union(dfsan_read_label(s, strlen(s) + 1),
 789                     dfsan_union(s_label, c_label));
 790   }
 791
 792   return ret;
 793 }
 794
 795 SANITIZER_INTERFACE_ATTRIBUTE char *__dfsw_strstr(char *haystack, char *needle,
 796                                                   dfsan_label haystack_label,
 797                                                   dfsan_label needle_label,
 798                                                   dfsan_label *ret_label) {
 799   char *ret = strstr(haystack, needle);
 800   if (flags().strict_data_dependencies) {
 801     *ret_label = ret ? haystack_label : 0;
 802   } else {
 803     size_t len = ret ? ret + strlen(needle) - haystack : strlen(haystack) + 1;
 804     *ret_label =
 805         dfsan_union(dfsan_read_label(haystack, len),
 806                     dfsan_union(dfsan_read_label(needle, strlen(needle) + 1),
 807                                 dfsan_union(haystack_label, needle_label)));
 808   }
 809
 810   return ret;
 811 }
 812
 813 SANITIZER_INTERFACE_ATTRIBUTE int __dfsw_nanosleep(const struct timespec *req,
 814                                                    struct timespec *rem,
 815                                                    dfsan_label req_label,
 816                                                    dfsan_label rem_label,
 817                                                    dfsan_label *ret_label) {
 818   int ret = nanosleep(req, rem);
 819   *ret_label = 0;
 820   if (ret == -1) {
 821     // Interrupted by a signal, rem is filled with the remaining time.
 822     dfsan_set_label(0, rem, sizeof(struct timespec));
 823   }
 824   return ret;
 825 }
 826
 827 SANITIZER_INTERFACE_ATTRIBUTE int
 828 __dfsw_socketpair(int domain, int type, int protocol, int sv[2],
 829                   dfsan_label domain_label, dfsan_label type_label,
 830                   dfsan_label protocol_label, dfsan_label sv_label,
 831                   dfsan_label *ret_label) {
 832   int ret = socketpair(domain, type, protocol, sv);
 833   *ret_label = 0;
 834   if (ret == 0) {
 835     dfsan_set_label(0, sv, sizeof(*sv) * 2);
 836   }
 837   return ret;
 838 }
 839
 840 // Type of the trampoline function passed to the custom version of
 841 // dfsan_set_write_callback.
 842 typedef void (*write_trampoline_t)(
 843     void *callback,
 844     int fd, const void *buf, ssize_t count,
 845     dfsan_label fd_label, dfsan_label buf_label, dfsan_label count_label);
 846
 847 // Calls to dfsan_set_write_callback() set the values in this struct.
 848 // Calls to the custom version of write() read (and invoke) them.
 849 static struct {
 850   write_trampoline_t write_callback_trampoline = nullptr;
 851   void *write_callback = nullptr;
 852 } write_callback_info;
 853
 854 SANITIZER_INTERFACE_ATTRIBUTE void
 855 __dfsw_dfsan_set_write_callback(
 856     write_trampoline_t write_callback_trampoline,
 857     void *write_callback,
 858     dfsan_label write_callback_label,
 859     dfsan_label *ret_label) {
 860   write_callback_info.write_callback_trampoline = write_callback_trampoline;
 861   write_callback_info.write_callback = write_callback;
 862 }
 863
 864 SANITIZER_INTERFACE_ATTRIBUTE int
 865 __dfsw_write(int fd, const void *buf, size_t count,
 866              dfsan_label fd_label, dfsan_label buf_label,
 867              dfsan_label count_label, dfsan_label *ret_label) {
 868   if (write_callback_info.write_callback) {
 869     write_callback_info.write_callback_trampoline(
 870         write_callback_info.write_callback,
 871         fd, buf, count,
 872         fd_label, buf_label, count_label);
 873   }
 874
 875   *ret_label = 0;
 876   return write(fd, buf, count);
 877 }
 878 } // namespace __dfsan
 879
 880 // Type used to extract a dfsan_label with va_arg()
 881 typedef int dfsan_label_va;
 882
 883 // Formats a chunk either a constant string or a single format directive (e.g.,
 884 // '%.3f').
 885 struct Formatter {
 886   Formatter(char *str_, const char *fmt_, size_t size_)
 887       : str(str_), str_off(0), size(size_), fmt_start(fmt_), fmt_cur(fmt_),
 888         width(-1) {}
 889
 890   int format() {
 891     char *tmp_fmt = build_format_string();
 892     int retval =
 893         snprintf(str + str_off, str_off < size ? size - str_off : 0, tmp_fmt,
 894                  0 /* used only to avoid warnings */);
 895     free(tmp_fmt);
 896     return retval;
 897   }
 898
 899   template <typename T> int format(T arg) {
 900     char *tmp_fmt = build_format_string();
 901     int retval;
 902     if (width >= 0) {
 903       retval = snprintf(str + str_off, str_off < size ? size - str_off : 0,
 904                         tmp_fmt, width, arg);
 905     } else {
 906       retval = snprintf(str + str_off, str_off < size ? size - str_off : 0,
 907                         tmp_fmt, arg);
 908     }
 909     free(tmp_fmt);
 910     return retval;
 911   }
 912
 913   char *build_format_string() {
 914     size_t fmt_size = fmt_cur - fmt_start + 1;
 915     char *new_fmt = (char *)malloc(fmt_size + 1);
 916     assert(new_fmt);
 917     internal_memcpy(new_fmt, fmt_start, fmt_size);
 918     new_fmt[fmt_size] = '\0';
 919     return new_fmt;
 920   }
 921
 922   char *str_cur() { return str + str_off; }
 923
 924   size_t num_written_bytes(int retval) {
 925     if (retval < 0) {
 926       return 0;
 927     }
 928
 929     size_t num_avail = str_off < size ? size - str_off : 0;
 930     if (num_avail == 0) {
 931       return 0;
 932     }
 933
 934     size_t num_written = retval;
 935     // A return value of {v,}snprintf of size or more means that the output was
 936     // truncated.
 937     if (num_written >= num_avail) {
 938       num_written -= num_avail;
 939     }
 940
 941     return num_written;
 942   }
 943
 944   char *str;
 945   size_t str_off;
 946   size_t size;
 947   const char *fmt_start;
 948   const char *fmt_cur;
 949   int width;
 950 };
 951
 952 // Formats the input and propagates the input labels to the output. The output
 953 // is stored in 'str'. 'size' bounds the number of output bytes. 'format' and
 954 // 'ap' are the format string and the list of arguments for formatting. Returns
 955 // the return value vsnprintf would return.
 956 //
 957 // The function tokenizes the format string in chunks representing either a
 958 // constant string or a single format directive (e.g., '%.3f') and formats each
 959 // chunk independently into the output string. This approach allows to figure
 960 // out which bytes of the output string depends on which argument and thus to
 961 // propagate labels more precisely.
 962 //
 963 // WARNING: This implementation does not support conversion specifiers with
 964 // positional arguments.
 965 static int format_buffer(char *str, size_t size, const char *fmt,
 966                          dfsan_label *va_labels, dfsan_label *ret_label,
 967                          va_list ap) {
 968   Formatter formatter(str, fmt, size);
 969
 970   while (*formatter.fmt_cur) {
 971     formatter.fmt_start = formatter.fmt_cur;
 972     formatter.width = -1;
 973     int retval = 0;
 974
 975     if (*formatter.fmt_cur != '%') {
 976       // Ordinary character. Consume all the characters until a '%' or the end
 977       // of the string.
 978       for (; *(formatter.fmt_cur + 1) && *(formatter.fmt_cur + 1) != '%';
 979            ++formatter.fmt_cur) {}
 980       retval = formatter.format();
 981       dfsan_set_label(0, formatter.str_cur(),
 982                       formatter.num_written_bytes(retval));
 983     } else {
 984       // Conversion directive. Consume all the characters until a conversion
 985       // specifier or the end of the string.
 986       bool end_fmt = false;
 987       for (; *formatter.fmt_cur && !end_fmt; ) {
 988         switch (*++formatter.fmt_cur) {
 989         case 'd':
 990         case 'i':
 991         case 'o':
 992         case 'u':
 993         case 'x':
 994         case 'X':
 995           switch (*(formatter.fmt_cur - 1)) {
 996           case 'h':
 997             // Also covers the 'hh' case (since the size of the arg is still
 998             // an int).
 999             retval = formatter.format(va_arg(ap, int));
1000             break;
1001           case 'l':
1002             if (formatter.fmt_cur - formatter.fmt_start >= 2 &&
1003                 *(formatter.fmt_cur - 2) == 'l') {
1004               retval = formatter.format(va_arg(ap, long long int));
1005             } else {
1006               retval = formatter.format(va_arg(ap, long int));
1007             }
1008             break;
1009           case 'q':
1010             retval = formatter.format(va_arg(ap, long long int));
1011             break;
1012           case 'j':
1013             retval = formatter.format(va_arg(ap, intmax_t));
1014             break;
1015           case 'z':
1016           case 't':
1017             retval = formatter.format(va_arg(ap, size_t));
1018             break;
1019           default:
1020             retval = formatter.format(va_arg(ap, int));
1021           }
1022           dfsan_set_label(*va_labels++, formatter.str_cur(),
1023                           formatter.num_written_bytes(retval));
1024           end_fmt = true;
1025           break;
1026
1027         case 'a':
1028         case 'A':
1029         case 'e':
1030         case 'E':
1031         case 'f':
1032         case 'F':
1033         case 'g':
1034         case 'G':
1035           if (*(formatter.fmt_cur - 1) == 'L') {
1036             retval = formatter.format(va_arg(ap, long double));
1037           } else {
1038             retval = formatter.format(va_arg(ap, double));
1039           }
1040           dfsan_set_label(*va_labels++, formatter.str_cur(),
1041                           formatter.num_written_bytes(retval));
1042           end_fmt = true;
1043           break;
1044
1045         case 'c':
1046           retval = formatter.format(va_arg(ap, int));
1047           dfsan_set_label(*va_labels++, formatter.str_cur(),
1048                           formatter.num_written_bytes(retval));
1049           end_fmt = true;
1050           break;
1051
1052         case 's': {
1053           char *arg = va_arg(ap, char *);
1054           retval = formatter.format(arg);
1055           va_labels++;
1056           internal_memcpy(shadow_for(formatter.str_cur()), shadow_for(arg),
1057                           sizeof(dfsan_label) *
1058                               formatter.num_written_bytes(retval));
1059           end_fmt = true;
1060           break;
1061         }
1062
1063         case 'p':
1064           retval = formatter.format(va_arg(ap, void *));
1065           dfsan_set_label(*va_labels++, formatter.str_cur(),
1066                           formatter.num_written_bytes(retval));
1067           end_fmt = true;
1068           break;
1069
1070         case 'n': {
1071           int *ptr = va_arg(ap, int *);
1072           *ptr = (int)formatter.str_off;
1073           va_labels++;
1074           dfsan_set_label(0, ptr, sizeof(ptr));
1075           end_fmt = true;
1076           break;
1077         }
1078
1079         case '%':
1080           retval = formatter.format();
1081           dfsan_set_label(0, formatter.str_cur(),
1082                           formatter.num_written_bytes(retval));
1083           end_fmt = true;
1084           break;
1085
1086         case '*':
1087           formatter.width = va_arg(ap, int);
1088           va_labels++;
1089           break;
1090
1091         default:
1092           break;
1093         }
1094       }
1095     }
1096
1097     if (retval < 0) {
1098       return retval;
1099     }
1100
1101     formatter.fmt_cur++;
1102     formatter.str_off += retval;
1103   }
1104
1105   *ret_label = 0;
1106
1107   // Number of bytes written in total.
1108   return formatter.str_off;
1109 }
1110
1111 extern "C" {
1112 SANITIZER_INTERFACE_ATTRIBUTE
1113 int __dfsw_sprintf(char *str, const char *format, dfsan_label str_label,
1114                    dfsan_label format_label, dfsan_label *va_labels,
1115                    dfsan_label *ret_label, ...) {
1116   va_list ap;
1117   va_start(ap, ret_label);
1118   int ret = format_buffer(str, ~0ul, format, va_labels, ret_label, ap);
1119   va_end(ap);
1120   return ret;
1121 }
1122
1123 SANITIZER_INTERFACE_ATTRIBUTE
1124 int __dfsw_snprintf(char *str, size_t size, const char *format,
1125                     dfsan_label str_label, dfsan_label size_label,
1126                     dfsan_label format_label, dfsan_label *va_labels,
1127                     dfsan_label *ret_label, ...) {
1128   va_list ap;
1129   va_start(ap, ret_label);
1130   int ret = format_buffer(str, size, format, va_labels, ret_label, ap);
1131   va_end(ap);
1132   return ret;
1133 }
1134
1135 // Default empty implementations (weak). Users should redefine them.
1136 SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_trace_pc_guard, u32 *) {}
1137 SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_trace_pc_guard_init, u32 *,
1138                              u32 *) {}
1139 SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_pcs_init, void) {}
1140 SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_trace_pc_indir, void) {}
1141
1142 SANITIZER_INTERFACE_WEAK_DEF(void, __dfsw___sanitizer_cov_trace_cmp, void) {}
1143 SANITIZER_INTERFACE_WEAK_DEF(void, __dfsw___sanitizer_cov_trace_cmp1, void) {}
1144 SANITIZER_INTERFACE_WEAK_DEF(void, __dfsw___sanitizer_cov_trace_cmp2, void) {}
1145 SANITIZER_INTERFACE_WEAK_DEF(void, __dfsw___sanitizer_cov_trace_cmp4, void) {}
1146 SANITIZER_INTERFACE_WEAK_DEF(void, __dfsw___sanitizer_cov_trace_cmp8, void) {}
1147 SANITIZER_INTERFACE_WEAK_DEF(void, __dfsw___sanitizer_cov_trace_const_cmp1,
1148                              void) {}
1149 SANITIZER_INTERFACE_WEAK_DEF(void, __dfsw___sanitizer_cov_trace_const_cmp2,
1150                              void) {}
1151 SANITIZER_INTERFACE_WEAK_DEF(void, __dfsw___sanitizer_cov_trace_const_cmp4,
1152                              void) {}
1153 SANITIZER_INTERFACE_WEAK_DEF(void, __dfsw___sanitizer_cov_trace_const_cmp8,
1154                              void) {}
1155 SANITIZER_INTERFACE_WEAK_DEF(void, __dfsw___sanitizer_cov_trace_switch, void) {}
1156 }  // extern "C"