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

   1 //===-- dfsan.cc ----------------------------------------------------------===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 //
  10 // This file is a part of DataFlowSanitizer.
  11 //
  12 // This file defines the custom functions listed in done_abilist.txt.
  13 //===----------------------------------------------------------------------===//
  14
  15 #include "sanitizer_common/sanitizer_common.h"
  16 #include "sanitizer_common/sanitizer_internal_defs.h"
  17 #include "sanitizer_common/sanitizer_linux.h"
  18
  19 #include "dfsan/dfsan.h"
  20
  21 #include <arpa/inet.h>
  22 #include <assert.h>
  23 #include <ctype.h>
  24 #include <dlfcn.h>
  25 #include <link.h>
  26 #include <poll.h>
  27 #include <pthread.h>
  28 #include <pwd.h>
  29 #include <sched.h>
  30 #include <signal.h>
  31 #include <stdarg.h>
  32 #include <stdint.h>
  33 #include <stdio.h>
  34 #include <stdlib.h>
  35 #include <string.h>
  36 #include <sys/resource.h>
  37 #include <sys/select.h>
  38 #include <sys/stat.h>
  39 #include <sys/time.h>
  40 #include <sys/types.h>
  41 #include <time.h>
  42 #include <unistd.h>
  43
  44 using namespace __dfsan;
  45
  46 #define CALL_WEAK_INTERCEPTOR_HOOK(f, ...)                                     \
  47   do {                                                                         \
  48     if (f)                                                                     \
  49       f(__VA_ARGS__);                                                          \
  50   } while (false)
  51 #define DECLARE_WEAK_INTERCEPTOR_HOOK(f, ...) \
  52 SANITIZER_INTERFACE_ATTRIBUTE SANITIZER_WEAK_ATTRIBUTE void f(__VA_ARGS__);
  53
  54 extern "C" {
  55 SANITIZER_INTERFACE_ATTRIBUTE int
  56 __dfsw_stat(const char *path, struct stat *buf, dfsan_label path_label,
  57             dfsan_label buf_label, dfsan_label *ret_label) {
  58   int ret = stat(path, buf);
  59   if (ret == 0)
  60     dfsan_set_label(0, buf, sizeof(struct stat));
  61   *ret_label = 0;
  62   return ret;
  63 }
  64
  65 SANITIZER_INTERFACE_ATTRIBUTE int __dfsw_fstat(int fd, struct stat *buf,
  66                                                dfsan_label fd_label,
  67                                                dfsan_label buf_label,
  68                                                dfsan_label *ret_label) {
  69   int ret = fstat(fd, buf);
  70   if (ret == 0)
  71     dfsan_set_label(0, buf, sizeof(struct stat));
  72   *ret_label = 0;
  73   return ret;
  74 }
  75
  76 SANITIZER_INTERFACE_ATTRIBUTE char *__dfsw_strchr(const char *s, int c,
  77                                                   dfsan_label s_label,
  78                                                   dfsan_label c_label,
  79                                                   dfsan_label *ret_label) {
  80   for (size_t i = 0;; ++i) {
  81     if (s[i] == c || s[i] == 0) {
  82       if (flags().strict_data_dependencies) {
  83         *ret_label = s_label;
  84       } else {
  85         *ret_label = dfsan_union(dfsan_read_label(s, i + 1),
  86                                  dfsan_union(s_label, c_label));
  87       }
  88       return s[i] == 0 ? nullptr : const_cast<char *>(s+i);
  89     }
  90   }
  91 }
  92
  93 DECLARE_WEAK_INTERCEPTOR_HOOK(dfsan_weak_hook_memcmp, uptr caller_pc,
  94                               const void *s1, const void *s2, size_t n,
  95                               dfsan_label s1_label, dfsan_label s2_label,
  96                               dfsan_label n_label)
  97
  98 SANITIZER_INTERFACE_ATTRIBUTE int __dfsw_memcmp(const void *s1, const void *s2,
  99                                                 size_t n, dfsan_label s1_label,
 100                                                 dfsan_label s2_label,
 101                                                 dfsan_label n_label,
 102                                                 dfsan_label *ret_label) {
 103   CALL_WEAK_INTERCEPTOR_HOOK(dfsan_weak_hook_memcmp, GET_CALLER_PC(), s1, s2, n,
 104                              s1_label, s2_label, n_label);
 105   const char *cs1 = (const char *) s1, *cs2 = (const char *) s2;
 106   for (size_t i = 0; i != n; ++i) {
 107     if (cs1[i] != cs2[i]) {
 108       if (flags().strict_data_dependencies) {
 109         *ret_label = 0;
 110       } else {
 111         *ret_label = dfsan_union(dfsan_read_label(cs1, i + 1),
 112                                  dfsan_read_label(cs2, i + 1));
 113       }
 114       return cs1[i] - cs2[i];
 115     }
 116   }
 117
 118   if (flags().strict_data_dependencies) {
 119     *ret_label = 0;
 120   } else {
 121     *ret_label = dfsan_union(dfsan_read_label(cs1, n),
 122                              dfsan_read_label(cs2, n));
 123   }
 124   return 0;
 125 }
 126
 127 DECLARE_WEAK_INTERCEPTOR_HOOK(dfsan_weak_hook_strcmp, uptr caller_pc,
 128                               const char *s1, const char *s2,
 129                               dfsan_label s1_label, dfsan_label s2_label)
 130
 131 SANITIZER_INTERFACE_ATTRIBUTE int __dfsw_strcmp(const char *s1, const char *s2,
 132                                                 dfsan_label s1_label,
 133                                                 dfsan_label s2_label,
 134                                                 dfsan_label *ret_label) {
 135   CALL_WEAK_INTERCEPTOR_HOOK(dfsan_weak_hook_strcmp, GET_CALLER_PC(), s1, s2,
 136                              s1_label, s2_label);
 137   for (size_t i = 0;; ++i) {
 138     if (s1[i] != s2[i] || s1[i] == 0 || s2[i] == 0) {
 139       if (flags().strict_data_dependencies) {
 140         *ret_label = 0;
 141       } else {
 142         *ret_label = dfsan_union(dfsan_read_label(s1, i + 1),
 143                                  dfsan_read_label(s2, i + 1));
 144       }
 145       return s1[i] - s2[i];
 146     }
 147   }
 148   return 0;
 149 }
 150
 151 SANITIZER_INTERFACE_ATTRIBUTE int
 152 __dfsw_strcasecmp(const char *s1, const char *s2, dfsan_label s1_label,
 153                   dfsan_label s2_label, dfsan_label *ret_label) {
 154   for (size_t i = 0;; ++i) {
 155     if (tolower(s1[i]) != tolower(s2[i]) || s1[i] == 0 || s2[i] == 0) {
 156       if (flags().strict_data_dependencies) {
 157         *ret_label = 0;
 158       } else {
 159         *ret_label = dfsan_union(dfsan_read_label(s1, i + 1),
 160                                  dfsan_read_label(s2, i + 1));
 161       }
 162       return s1[i] - s2[i];
 163     }
 164   }
 165   return 0;
 166 }
 167
 168 DECLARE_WEAK_INTERCEPTOR_HOOK(dfsan_weak_hook_strncmp, uptr caller_pc,
 169                               const char *s1, const char *s2, size_t n,
 170                               dfsan_label s1_label, dfsan_label s2_label,
 171                               dfsan_label n_label)
 172
 173 SANITIZER_INTERFACE_ATTRIBUTE int __dfsw_strncmp(const char *s1, const char *s2,
 174                                                  size_t n, dfsan_label s1_label,
 175                                                  dfsan_label s2_label,
 176                                                  dfsan_label n_label,
 177                                                  dfsan_label *ret_label) {
 178   if (n == 0) {
 179     *ret_label = 0;
 180     return 0;
 181   }
 182
 183   CALL_WEAK_INTERCEPTOR_HOOK(dfsan_weak_hook_strncmp, GET_CALLER_PC(), s1, s2,
 184                              n, s1_label, s2_label, n_label);
 185
 186   for (size_t i = 0;; ++i) {
 187     if (s1[i] != s2[i] || s1[i] == 0 || s2[i] == 0 || i == n - 1) {
 188       if (flags().strict_data_dependencies) {
 189         *ret_label = 0;
 190       } else {
 191         *ret_label = dfsan_union(dfsan_read_label(s1, i + 1),
 192                                  dfsan_read_label(s2, i + 1));
 193       }
 194       return s1[i] - s2[i];
 195     }
 196   }
 197   return 0;
 198 }
 199
 200 SANITIZER_INTERFACE_ATTRIBUTE int
 201 __dfsw_strncasecmp(const char *s1, const char *s2, size_t n,
 202                    dfsan_label s1_label, dfsan_label s2_label,
 203                    dfsan_label n_label, dfsan_label *ret_label) {
 204   if (n == 0) {
 205     *ret_label = 0;
 206     return 0;
 207   }
 208
 209   for (size_t i = 0;; ++i) {
 210     if (tolower(s1[i]) != tolower(s2[i]) || s1[i] == 0 || s2[i] == 0 ||
 211         i == n - 1) {
 212       if (flags().strict_data_dependencies) {
 213         *ret_label = 0;
 214       } else {
 215         *ret_label = dfsan_union(dfsan_read_label(s1, i + 1),
 216                                  dfsan_read_label(s2, i + 1));
 217       }
 218       return s1[i] - s2[i];
 219     }
 220   }
 221   return 0;
 222 }
 223
 224 SANITIZER_INTERFACE_ATTRIBUTE void *__dfsw_calloc(size_t nmemb, size_t size,
 225                                                   dfsan_label nmemb_label,
 226                                                   dfsan_label size_label,
 227                                                   dfsan_label *ret_label) {
 228   void *p = calloc(nmemb, size);
 229   dfsan_set_label(0, p, nmemb * size);
 230   *ret_label = 0;
 231   return p;
 232 }
 233
 234 SANITIZER_INTERFACE_ATTRIBUTE size_t
 235 __dfsw_strlen(const char *s, dfsan_label s_label, dfsan_label *ret_label) {
 236   size_t ret = strlen(s);
 237   if (flags().strict_data_dependencies) {
 238     *ret_label = 0;
 239   } else {
 240     *ret_label = dfsan_read_label(s, ret + 1);
 241   }
 242   return ret;
 243 }
 244
 245
 246 static void *dfsan_memcpy(void *dest, const void *src, size_t n) {
 247   dfsan_label *sdest = shadow_for(dest);
 248   const dfsan_label *ssrc = shadow_for(src);
 249   internal_memcpy((void *)sdest, (const void *)ssrc, n * sizeof(dfsan_label));
 250   return internal_memcpy(dest, src, n);
 251 }
 252
 253 static void dfsan_memset(void *s, int c, dfsan_label c_label, size_t n) {
 254   internal_memset(s, c, n);
 255   dfsan_set_label(c_label, s, n);
 256 }
 257
 258 SANITIZER_INTERFACE_ATTRIBUTE
 259 void *__dfsw_memcpy(void *dest, const void *src, size_t n,
 260                     dfsan_label dest_label, dfsan_label src_label,
 261                     dfsan_label n_label, dfsan_label *ret_label) {
 262   *ret_label = dest_label;
 263   return dfsan_memcpy(dest, src, n);
 264 }
 265
 266 SANITIZER_INTERFACE_ATTRIBUTE
 267 void *__dfsw_memset(void *s, int c, size_t n,
 268                     dfsan_label s_label, dfsan_label c_label,
 269                     dfsan_label n_label, dfsan_label *ret_label) {
 270   dfsan_memset(s, c, c_label, n);
 271   *ret_label = s_label;
 272   return s;
 273 }
 274
 275 SANITIZER_INTERFACE_ATTRIBUTE char *
 276 __dfsw_strdup(const char *s, dfsan_label s_label, dfsan_label *ret_label) {
 277   size_t len = strlen(s);
 278   void *p = malloc(len+1);
 279   dfsan_memcpy(p, s, len+1);
 280   *ret_label = 0;
 281   return static_cast<char *>(p);
 282 }
 283
 284 SANITIZER_INTERFACE_ATTRIBUTE char *
 285 __dfsw_strncpy(char *s1, const char *s2, size_t n, dfsan_label s1_label,
 286                dfsan_label s2_label, dfsan_label n_label,
 287                dfsan_label *ret_label) {
 288   size_t len = strlen(s2);
 289   if (len < n) {
 290     dfsan_memcpy(s1, s2, len+1);
 291     dfsan_memset(s1+len+1, 0, 0, n-len-1);
 292   } else {
 293     dfsan_memcpy(s1, s2, n);
 294   }
 295
 296   *ret_label = s1_label;
 297   return s1;
 298 }
 299
 300 SANITIZER_INTERFACE_ATTRIBUTE ssize_t
 301 __dfsw_pread(int fd, void *buf, size_t count, off_t offset,
 302              dfsan_label fd_label, dfsan_label buf_label,
 303              dfsan_label count_label, dfsan_label offset_label,
 304              dfsan_label *ret_label) {
 305   ssize_t ret = pread(fd, buf, count, offset);
 306   if (ret > 0)
 307     dfsan_set_label(0, buf, ret);
 308   *ret_label = 0;
 309   return ret;
 310 }
 311
 312 SANITIZER_INTERFACE_ATTRIBUTE ssize_t
 313 __dfsw_read(int fd, void *buf, size_t count,
 314              dfsan_label fd_label, dfsan_label buf_label,
 315              dfsan_label count_label,
 316              dfsan_label *ret_label) {
 317   ssize_t ret = read(fd, buf, count);
 318   if (ret > 0)
 319     dfsan_set_label(0, buf, ret);
 320   *ret_label = 0;
 321   return ret;
 322 }
 323
 324 SANITIZER_INTERFACE_ATTRIBUTE int __dfsw_clock_gettime(clockid_t clk_id,
 325                                                        struct timespec *tp,
 326                                                        dfsan_label clk_id_label,
 327                                                        dfsan_label tp_label,
 328                                                        dfsan_label *ret_label) {
 329   int ret = clock_gettime(clk_id, tp);
 330   if (ret == 0)
 331     dfsan_set_label(0, tp, sizeof(struct timespec));
 332   *ret_label = 0;
 333   return ret;
 334 }
 335
 336 static void unpoison(const void *ptr, uptr size) {
 337   dfsan_set_label(0, const_cast<void *>(ptr), size);
 338 }
 339
 340 // dlopen() ultimately calls mmap() down inside the loader, which generally
 341 // doesn't participate in dynamic symbol resolution.  Therefore we won't
 342 // intercept its calls to mmap, and we have to hook it here.
 343 SANITIZER_INTERFACE_ATTRIBUTE void *
 344 __dfsw_dlopen(const char *filename, int flag, dfsan_label filename_label,
 345               dfsan_label flag_label, dfsan_label *ret_label) {
 346   void *handle = dlopen(filename, flag);
 347   link_map *map = GET_LINK_MAP_BY_DLOPEN_HANDLE(handle);
 348   if (map)
 349     ForEachMappedRegion(map, unpoison);
 350   *ret_label = 0;
 351   return handle;
 352 }
 353
 354 struct pthread_create_info {
 355   void *(*start_routine_trampoline)(void *, void *, dfsan_label, dfsan_label *);
 356   void *start_routine;
 357   void *arg;
 358 };
 359
 360 static void *pthread_create_cb(void *p) {
 361   pthread_create_info pci(*(pthread_create_info *)p);
 362   free(p);
 363   dfsan_label ret_label;
 364   return pci.start_routine_trampoline(pci.start_routine, pci.arg, 0,
 365                                       &ret_label);
 366 }
 367
 368 SANITIZER_INTERFACE_ATTRIBUTE int __dfsw_pthread_create(
 369     pthread_t *thread, const pthread_attr_t *attr,
 370     void *(*start_routine_trampoline)(void *, void *, dfsan_label,
 371                                       dfsan_label *),
 372     void *start_routine, void *arg, dfsan_label thread_label,
 373     dfsan_label attr_label, dfsan_label start_routine_label,
 374     dfsan_label arg_label, dfsan_label *ret_label) {
 375   pthread_create_info *pci =
 376       (pthread_create_info *)malloc(sizeof(pthread_create_info));
 377   pci->start_routine_trampoline = start_routine_trampoline;
 378   pci->start_routine = start_routine;
 379   pci->arg = arg;
 380   int rv = pthread_create(thread, attr, pthread_create_cb, (void *)pci);
 381   if (rv != 0)
 382     free(pci);
 383   *ret_label = 0;
 384   return rv;
 385 }
 386
 387 struct dl_iterate_phdr_info {
 388   int (*callback_trampoline)(void *callback, struct dl_phdr_info *info,
 389                              size_t size, void *data, dfsan_label info_label,
 390                              dfsan_label size_label, dfsan_label data_label,
 391                              dfsan_label *ret_label);
 392   void *callback;
 393   void *data;
 394 };
 395
 396 int dl_iterate_phdr_cb(struct dl_phdr_info *info, size_t size, void *data) {
 397   dl_iterate_phdr_info *dipi = (dl_iterate_phdr_info *)data;
 398   dfsan_set_label(0, *info);
 399   dfsan_set_label(0, const_cast<char *>(info->dlpi_name),
 400                   strlen(info->dlpi_name) + 1);
 401   dfsan_set_label(
 402       0, const_cast<char *>(reinterpret_cast<const char *>(info->dlpi_phdr)),
 403       sizeof(*info->dlpi_phdr) * info->dlpi_phnum);
 404   dfsan_label ret_label;
 405   return dipi->callback_trampoline(dipi->callback, info, size, dipi->data, 0, 0,
 406                                    0, &ret_label);
 407 }
 408
 409 SANITIZER_INTERFACE_ATTRIBUTE int __dfsw_dl_iterate_phdr(
 410     int (*callback_trampoline)(void *callback, struct dl_phdr_info *info,
 411                                size_t size, void *data, dfsan_label info_label,
 412                                dfsan_label size_label, dfsan_label data_label,
 413                                dfsan_label *ret_label),
 414     void *callback, void *data, dfsan_label callback_label,
 415     dfsan_label data_label, dfsan_label *ret_label) {
 416   dl_iterate_phdr_info dipi = { callback_trampoline, callback, data };
 417   *ret_label = 0;
 418   return dl_iterate_phdr(dl_iterate_phdr_cb, &dipi);
 419 }
 420
 421 SANITIZER_INTERFACE_ATTRIBUTE
 422 char *__dfsw_ctime_r(const time_t *timep, char *buf, dfsan_label timep_label,
 423                      dfsan_label buf_label, dfsan_label *ret_label) {
 424   char *ret = ctime_r(timep, buf);
 425   if (ret) {
 426     dfsan_set_label(dfsan_read_label(timep, sizeof(time_t)), buf,
 427                     strlen(buf) + 1);
 428     *ret_label = buf_label;
 429   } else {
 430     *ret_label = 0;
 431   }
 432   return ret;
 433 }
 434
 435 SANITIZER_INTERFACE_ATTRIBUTE
 436 char *__dfsw_fgets(char *s, int size, FILE *stream, dfsan_label s_label,
 437                    dfsan_label size_label, dfsan_label stream_label,
 438                    dfsan_label *ret_label) {
 439   char *ret = fgets(s, size, stream);
 440   if (ret) {
 441     dfsan_set_label(0, ret, strlen(ret) + 1);
 442     *ret_label = s_label;
 443   } else {
 444     *ret_label = 0;
 445   }
 446   return ret;
 447 }
 448
 449 SANITIZER_INTERFACE_ATTRIBUTE
 450 char *__dfsw_getcwd(char *buf, size_t size, dfsan_label buf_label,
 451                     dfsan_label size_label, dfsan_label *ret_label) {
 452   char *ret = getcwd(buf, size);
 453   if (ret) {
 454     dfsan_set_label(0, ret, strlen(ret) + 1);
 455     *ret_label = buf_label;
 456   } else {
 457     *ret_label = 0;
 458   }
 459   return ret;
 460 }
 461
 462 SANITIZER_INTERFACE_ATTRIBUTE
 463 char *__dfsw_get_current_dir_name(dfsan_label *ret_label) {
 464   char *ret = get_current_dir_name();
 465   if (ret) {
 466     dfsan_set_label(0, ret, strlen(ret) + 1);
 467   }
 468   *ret_label = 0;
 469   return ret;
 470 }
 471
 472 SANITIZER_INTERFACE_ATTRIBUTE
 473 int __dfsw_gethostname(char *name, size_t len, dfsan_label name_label,
 474                        dfsan_label len_label, dfsan_label *ret_label) {
 475   int ret = gethostname(name, len);
 476   if (ret == 0) {
 477     dfsan_set_label(0, name, strlen(name) + 1);
 478   }
 479   *ret_label = 0;
 480   return ret;
 481 }
 482
 483 SANITIZER_INTERFACE_ATTRIBUTE
 484 int __dfsw_getrlimit(int resource, struct rlimit *rlim,
 485                      dfsan_label resource_label, dfsan_label rlim_label,
 486                      dfsan_label *ret_label) {
 487   int ret = getrlimit(resource, rlim);
 488   if (ret == 0) {
 489     dfsan_set_label(0, rlim, sizeof(struct rlimit));
 490   }
 491   *ret_label = 0;
 492   return ret;
 493 }
 494
 495 SANITIZER_INTERFACE_ATTRIBUTE
 496 int __dfsw_getrusage(int who, struct rusage *usage, dfsan_label who_label,
 497                      dfsan_label usage_label, dfsan_label *ret_label) {
 498   int ret = getrusage(who, usage);
 499   if (ret == 0) {
 500     dfsan_set_label(0, usage, sizeof(struct rusage));
 501   }
 502   *ret_label = 0;
 503   return ret;
 504 }
 505
 506 SANITIZER_INTERFACE_ATTRIBUTE
 507 char *__dfsw_strcpy(char *dest, const char *src, dfsan_label dst_label,
 508                     dfsan_label src_label, dfsan_label *ret_label) {
 509   char *ret = strcpy(dest, src);
 510   if (ret) {
 511     internal_memcpy(shadow_for(dest), shadow_for(src),
 512                     sizeof(dfsan_label) * (strlen(src) + 1));
 513   }
 514   *ret_label = dst_label;
 515   return ret;
 516 }
 517
 518 SANITIZER_INTERFACE_ATTRIBUTE
 519 long int __dfsw_strtol(const char *nptr, char **endptr, int base,
 520                        dfsan_label nptr_label, dfsan_label endptr_label,
 521                        dfsan_label base_label, dfsan_label *ret_label) {
 522   char *tmp_endptr;
 523   long int ret = strtol(nptr, &tmp_endptr, base);
 524   if (endptr) {
 525     *endptr = tmp_endptr;
 526   }
 527   if (tmp_endptr > nptr) {
 528     // If *tmp_endptr is '\0' include its label as well.
 529     *ret_label = dfsan_union(
 530         base_label,
 531         dfsan_read_label(nptr, tmp_endptr - nptr + (*tmp_endptr ? 0 : 1)));
 532   } else {
 533     *ret_label = 0;
 534   }
 535   return ret;
 536 }
 537
 538 SANITIZER_INTERFACE_ATTRIBUTE
 539 double __dfsw_strtod(const char *nptr, char **endptr,
 540                        dfsan_label nptr_label, dfsan_label endptr_label,
 541                        dfsan_label *ret_label) {
 542   char *tmp_endptr;
 543   double ret = strtod(nptr, &tmp_endptr);
 544   if (endptr) {
 545     *endptr = tmp_endptr;
 546   }
 547   if (tmp_endptr > nptr) {
 548     // If *tmp_endptr is '\0' include its label as well.
 549     *ret_label = dfsan_read_label(
 550         nptr,
 551         tmp_endptr - nptr + (*tmp_endptr ? 0 : 1));
 552   } else {
 553     *ret_label = 0;
 554   }
 555   return ret;
 556 }
 557
 558 SANITIZER_INTERFACE_ATTRIBUTE
 559 long long int __dfsw_strtoll(const char *nptr, char **endptr, int base,
 560                        dfsan_label nptr_label, dfsan_label endptr_label,
 561                        dfsan_label base_label, dfsan_label *ret_label) {
 562   char *tmp_endptr;
 563   long long int ret = strtoll(nptr, &tmp_endptr, base);
 564   if (endptr) {
 565     *endptr = tmp_endptr;
 566   }
 567   if (tmp_endptr > nptr) {
 568     // If *tmp_endptr is '\0' include its label as well.
 569     *ret_label = dfsan_union(
 570         base_label,
 571         dfsan_read_label(nptr, tmp_endptr - nptr + (*tmp_endptr ? 0 : 1)));
 572   } else {
 573     *ret_label = 0;
 574   }
 575   return ret;
 576 }
 577
 578 SANITIZER_INTERFACE_ATTRIBUTE
 579 unsigned long int __dfsw_strtoul(const char *nptr, char **endptr, int base,
 580                        dfsan_label nptr_label, dfsan_label endptr_label,
 581                        dfsan_label base_label, dfsan_label *ret_label) {
 582   char *tmp_endptr;
 583   unsigned long int ret = strtoul(nptr, &tmp_endptr, base);
 584   if (endptr) {
 585     *endptr = tmp_endptr;
 586   }
 587   if (tmp_endptr > nptr) {
 588     // If *tmp_endptr is '\0' include its label as well.
 589     *ret_label = dfsan_union(
 590         base_label,
 591         dfsan_read_label(nptr, tmp_endptr - nptr + (*tmp_endptr ? 0 : 1)));
 592   } else {
 593     *ret_label = 0;
 594   }
 595   return ret;
 596 }
 597
 598 SANITIZER_INTERFACE_ATTRIBUTE
 599 long long unsigned int __dfsw_strtoull(const char *nptr, char **endptr,
 600                                        dfsan_label nptr_label,
 601                                        int base, dfsan_label endptr_label,
 602                                        dfsan_label base_label,
 603                                        dfsan_label *ret_label) {
 604   char *tmp_endptr;
 605   long long unsigned int ret = strtoull(nptr, &tmp_endptr, base);
 606   if (endptr) {
 607     *endptr = tmp_endptr;
 608   }
 609   if (tmp_endptr > nptr) {
 610     // If *tmp_endptr is '\0' include its label as well.
 611     *ret_label = dfsan_union(
 612         base_label,
 613         dfsan_read_label(nptr, tmp_endptr - nptr + (*tmp_endptr ? 0 : 1)));
 614   } else {
 615     *ret_label = 0;
 616   }
 617   return ret;
 618 }
 619
 620 SANITIZER_INTERFACE_ATTRIBUTE
 621 time_t __dfsw_time(time_t *t, dfsan_label t_label, dfsan_label *ret_label) {
 622   time_t ret = time(t);
 623   if (ret != (time_t) -1 && t) {
 624     dfsan_set_label(0, t, sizeof(time_t));
 625   }
 626   *ret_label = 0;
 627   return ret;
 628 }
 629
 630 SANITIZER_INTERFACE_ATTRIBUTE
 631 int __dfsw_inet_pton(int af, const char *src, void *dst, dfsan_label af_label,
 632                      dfsan_label src_label, dfsan_label dst_label,
 633                      dfsan_label *ret_label) {
 634   int ret = inet_pton(af, src, dst);
 635   if (ret == 1) {
 636     dfsan_set_label(dfsan_read_label(src, strlen(src) + 1), dst,
 637                     af == AF_INET ? sizeof(struct in_addr) : sizeof(in6_addr));
 638   }
 639   *ret_label = 0;
 640   return ret;
 641 }
 642
 643 SANITIZER_INTERFACE_ATTRIBUTE
 644 struct tm *__dfsw_localtime_r(const time_t *timep, struct tm *result,
 645                               dfsan_label timep_label, dfsan_label result_label,
 646                               dfsan_label *ret_label) {
 647   struct tm *ret = localtime_r(timep, result);
 648   if (ret) {
 649     dfsan_set_label(dfsan_read_label(timep, sizeof(time_t)), result,
 650                     sizeof(struct tm));
 651     *ret_label = result_label;
 652   } else {
 653     *ret_label = 0;
 654   }
 655   return ret;
 656 }
 657
 658 SANITIZER_INTERFACE_ATTRIBUTE
 659 int __dfsw_getpwuid_r(id_t uid, struct passwd *pwd,
 660                       char *buf, size_t buflen, struct passwd **result,
 661                       dfsan_label uid_label, dfsan_label pwd_label,
 662                       dfsan_label buf_label, dfsan_label buflen_label,
 663                       dfsan_label result_label, dfsan_label *ret_label) {
 664   // Store the data in pwd, the strings referenced from pwd in buf, and the
 665   // address of pwd in *result.  On failure, NULL is stored in *result.
 666   int ret = getpwuid_r(uid, pwd, buf, buflen, result);
 667   if (ret == 0) {
 668     dfsan_set_label(0, pwd, sizeof(struct passwd));
 669     dfsan_set_label(0, buf, strlen(buf) + 1);
 670   }
 671   *ret_label = 0;
 672   dfsan_set_label(0, result, sizeof(struct passwd*));
 673   return ret;
 674 }
 675
 676 SANITIZER_INTERFACE_ATTRIBUTE
 677 int __dfsw_poll(struct pollfd *fds, nfds_t nfds, int timeout,
 678                 dfsan_label dfs_label, dfsan_label nfds_label,
 679                 dfsan_label timeout_label, dfsan_label *ret_label) {
 680   int ret = poll(fds, nfds, timeout);
 681   if (ret >= 0) {
 682     for (; nfds > 0; --nfds) {
 683       dfsan_set_label(0, &fds[nfds - 1].revents, sizeof(fds[nfds - 1].revents));
 684     }
 685   }
 686   *ret_label = 0;
 687   return ret;
 688 }
 689
 690 SANITIZER_INTERFACE_ATTRIBUTE
 691 int __dfsw_select(int nfds, fd_set *readfds, fd_set *writefds,
 692                   fd_set *exceptfds, struct timeval *timeout,
 693                   dfsan_label nfds_label, dfsan_label readfds_label,
 694                   dfsan_label writefds_label, dfsan_label exceptfds_label,
 695                   dfsan_label timeout_label, dfsan_label *ret_label) {
 696   int ret = select(nfds, readfds, writefds, exceptfds, timeout);
 697   // Clear everything (also on error) since their content is either set or
 698   // undefined.
 699   if (readfds) {
 700     dfsan_set_label(0, readfds, sizeof(fd_set));
 701   }
 702   if (writefds) {
 703     dfsan_set_label(0, writefds, sizeof(fd_set));
 704   }
 705   if (exceptfds) {
 706     dfsan_set_label(0, exceptfds, sizeof(fd_set));
 707   }
 708   dfsan_set_label(0, timeout, sizeof(struct timeval));
 709   *ret_label = 0;
 710   return ret;
 711 }
 712
 713 SANITIZER_INTERFACE_ATTRIBUTE
 714 int __dfsw_sched_getaffinity(pid_t pid, size_t cpusetsize, cpu_set_t *mask,
 715                              dfsan_label pid_label,
 716                              dfsan_label cpusetsize_label,
 717                              dfsan_label mask_label, dfsan_label *ret_label) {
 718   int ret = sched_getaffinity(pid, cpusetsize, mask);
 719   if (ret == 0) {
 720     dfsan_set_label(0, mask, cpusetsize);
 721   }
 722   *ret_label = 0;
 723   return ret;
 724 }
 725
 726 SANITIZER_INTERFACE_ATTRIBUTE
 727 int __dfsw_sigemptyset(sigset_t *set, dfsan_label set_label,
 728                        dfsan_label *ret_label) {
 729   int ret = sigemptyset(set);
 730   dfsan_set_label(0, set, sizeof(sigset_t));
 731   return ret;
 732 }
 733
 734 SANITIZER_INTERFACE_ATTRIBUTE
 735 int __dfsw_sigaction(int signum, const struct sigaction *act,
 736                      struct sigaction *oldact, dfsan_label signum_label,
 737                      dfsan_label act_label, dfsan_label oldact_label,
 738                      dfsan_label *ret_label) {
 739   int ret = sigaction(signum, act, oldact);
 740   if (oldact) {
 741     dfsan_set_label(0, oldact, sizeof(struct sigaction));
 742   }
 743   *ret_label = 0;
 744   return ret;
 745 }
 746
 747 SANITIZER_INTERFACE_ATTRIBUTE
 748 int __dfsw_gettimeofday(struct timeval *tv, struct timezone *tz,
 749                         dfsan_label tv_label, dfsan_label tz_label,
 750                         dfsan_label *ret_label) {
 751   int ret = gettimeofday(tv, tz);
 752   if (tv) {
 753     dfsan_set_label(0, tv, sizeof(struct timeval));
 754   }
 755   if (tz) {
 756     dfsan_set_label(0, tz, sizeof(struct timezone));
 757   }
 758   *ret_label = 0;
 759   return ret;
 760 }
 761
 762 SANITIZER_INTERFACE_ATTRIBUTE void *__dfsw_memchr(void *s, int c, size_t n,
 763                                                   dfsan_label s_label,
 764                                                   dfsan_label c_label,
 765                                                   dfsan_label n_label,
 766                                                   dfsan_label *ret_label) {
 767   void *ret = memchr(s, c, n);
 768   if (flags().strict_data_dependencies) {
 769     *ret_label = ret ? s_label : 0;
 770   } else {
 771     size_t len =
 772         ret ? reinterpret_cast<char *>(ret) - reinterpret_cast<char *>(s) + 1
 773             : n;
 774     *ret_label =
 775         dfsan_union(dfsan_read_label(s, len), dfsan_union(s_label, c_label));
 776   }
 777   return ret;
 778 }
 779
 780 SANITIZER_INTERFACE_ATTRIBUTE char *__dfsw_strrchr(char *s, int c,
 781                                                    dfsan_label s_label,
 782                                                    dfsan_label c_label,
 783                                                    dfsan_label *ret_label) {
 784   char *ret = strrchr(s, c);
 785   if (flags().strict_data_dependencies) {
 786     *ret_label = ret ? s_label : 0;
 787   } else {
 788     *ret_label =
 789         dfsan_union(dfsan_read_label(s, strlen(s) + 1),
 790                     dfsan_union(s_label, c_label));
 791   }
 792
 793   return ret;
 794 }
 795
 796 SANITIZER_INTERFACE_ATTRIBUTE char *__dfsw_strstr(char *haystack, char *needle,
 797                                                   dfsan_label haystack_label,
 798                                                   dfsan_label needle_label,
 799                                                   dfsan_label *ret_label) {
 800   char *ret = strstr(haystack, needle);
 801   if (flags().strict_data_dependencies) {
 802     *ret_label = ret ? haystack_label : 0;
 803   } else {
 804     size_t len = ret ? ret + strlen(needle) - haystack : strlen(haystack) + 1;
 805     *ret_label =
 806         dfsan_union(dfsan_read_label(haystack, len),
 807                     dfsan_union(dfsan_read_label(needle, strlen(needle) + 1),
 808                                 dfsan_union(haystack_label, needle_label)));
 809   }
 810
 811   return ret;
 812 }
 813
 814 SANITIZER_INTERFACE_ATTRIBUTE int __dfsw_nanosleep(const struct timespec *req,
 815                                                    struct timespec *rem,
 816                                                    dfsan_label req_label,
 817                                                    dfsan_label rem_label,
 818                                                    dfsan_label *ret_label) {
 819   int ret = nanosleep(req, rem);
 820   *ret_label = 0;
 821   if (ret == -1) {
 822     // Interrupted by a signal, rem is filled with the remaining time.
 823     dfsan_set_label(0, rem, sizeof(struct timespec));
 824   }
 825   return ret;
 826 }
 827
 828 SANITIZER_INTERFACE_ATTRIBUTE int
 829 __dfsw_socketpair(int domain, int type, int protocol, int sv[2],
 830                   dfsan_label domain_label, dfsan_label type_label,
 831                   dfsan_label protocol_label, dfsan_label sv_label,
 832                   dfsan_label *ret_label) {
 833   int ret = socketpair(domain, type, protocol, sv);
 834   *ret_label = 0;
 835   if (ret == 0) {
 836     dfsan_set_label(0, sv, sizeof(*sv) * 2);
 837   }
 838   return ret;
 839 }
 840
 841 // Type of the trampoline function passed to the custom version of
 842 // dfsan_set_write_callback.
 843 typedef void (*write_trampoline_t)(
 844     void *callback,
 845     int fd, const void *buf, ssize_t count,
 846     dfsan_label fd_label, dfsan_label buf_label, dfsan_label count_label);
 847
 848 // Calls to dfsan_set_write_callback() set the values in this struct.
 849 // Calls to the custom version of write() read (and invoke) them.
 850 static struct {
 851   write_trampoline_t write_callback_trampoline = nullptr;
 852   void *write_callback = nullptr;
 853 } write_callback_info;
 854
 855 SANITIZER_INTERFACE_ATTRIBUTE void
 856 __dfsw_dfsan_set_write_callback(
 857     write_trampoline_t write_callback_trampoline,
 858     void *write_callback,
 859     dfsan_label write_callback_label,
 860     dfsan_label *ret_label) {
 861   write_callback_info.write_callback_trampoline = write_callback_trampoline;
 862   write_callback_info.write_callback = write_callback;
 863 }
 864
 865 SANITIZER_INTERFACE_ATTRIBUTE int
 866 __dfsw_write(int fd, const void *buf, size_t count,
 867              dfsan_label fd_label, dfsan_label buf_label,
 868              dfsan_label count_label, dfsan_label *ret_label) {
 869   if (write_callback_info.write_callback) {
 870     write_callback_info.write_callback_trampoline(
 871         write_callback_info.write_callback,
 872         fd, buf, count,
 873         fd_label, buf_label, count_label);
 874   }
 875
 876   *ret_label = 0;
 877   return write(fd, buf, count);
 878 }
 879 } // namespace __dfsan
 880
 881 // Type used to extract a dfsan_label with va_arg()
 882 typedef int dfsan_label_va;
 883
 884 // Formats a chunk either a constant string or a single format directive (e.g.,
 885 // '%.3f').
 886 struct Formatter {
 887   Formatter(char *str_, const char *fmt_, size_t size_)
 888       : str(str_), str_off(0), size(size_), fmt_start(fmt_), fmt_cur(fmt_),
 889         width(-1) {}
 890
 891   int format() {
 892     char *tmp_fmt = build_format_string();
 893     int retval =
 894         snprintf(str + str_off, str_off < size ? size - str_off : 0, tmp_fmt,
 895                  0 /* used only to avoid warnings */);
 896     free(tmp_fmt);
 897     return retval;
 898   }
 899
 900   template <typename T> int format(T arg) {
 901     char *tmp_fmt = build_format_string();
 902     int retval;
 903     if (width >= 0) {
 904       retval = snprintf(str + str_off, str_off < size ? size - str_off : 0,
 905                         tmp_fmt, width, arg);
 906     } else {
 907       retval = snprintf(str + str_off, str_off < size ? size - str_off : 0,
 908                         tmp_fmt, arg);
 909     }
 910     free(tmp_fmt);
 911     return retval;
 912   }
 913
 914   char *build_format_string() {
 915     size_t fmt_size = fmt_cur - fmt_start + 1;
 916     char *new_fmt = (char *)malloc(fmt_size + 1);
 917     assert(new_fmt);
 918     internal_memcpy(new_fmt, fmt_start, fmt_size);
 919     new_fmt[fmt_size] = '\0';
 920     return new_fmt;
 921   }
 922
 923   char *str_cur() { return str + str_off; }
 924
 925   size_t num_written_bytes(int retval) {
 926     if (retval < 0) {
 927       return 0;
 928     }
 929
 930     size_t num_avail = str_off < size ? size - str_off : 0;
 931     if (num_avail == 0) {
 932       return 0;
 933     }
 934
 935     size_t num_written = retval;
 936     // A return value of {v,}snprintf of size or more means that the output was
 937     // truncated.
 938     if (num_written >= num_avail) {
 939       num_written -= num_avail;
 940     }
 941
 942     return num_written;
 943   }
 944
 945   char *str;
 946   size_t str_off;
 947   size_t size;
 948   const char *fmt_start;
 949   const char *fmt_cur;
 950   int width;
 951 };
 952
 953 // Formats the input and propagates the input labels to the output. The output
 954 // is stored in 'str'. 'size' bounds the number of output bytes. 'format' and
 955 // 'ap' are the format string and the list of arguments for formatting. Returns
 956 // the return value vsnprintf would return.
 957 //
 958 // The function tokenizes the format string in chunks representing either a
 959 // constant string or a single format directive (e.g., '%.3f') and formats each
 960 // chunk independently into the output string. This approach allows to figure
 961 // out which bytes of the output string depends on which argument and thus to
 962 // propagate labels more precisely.
 963 //
 964 // WARNING: This implementation does not support conversion specifiers with
 965 // positional arguments.
 966 static int format_buffer(char *str, size_t size, const char *fmt,
 967                          dfsan_label *va_labels, dfsan_label *ret_label,
 968                          va_list ap) {
 969   Formatter formatter(str, fmt, size);
 970
 971   while (*formatter.fmt_cur) {
 972     formatter.fmt_start = formatter.fmt_cur;
 973     formatter.width = -1;
 974     int retval = 0;
 975
 976     if (*formatter.fmt_cur != '%') {
 977       // Ordinary character. Consume all the characters until a '%' or the end
 978       // of the string.
 979       for (; *(formatter.fmt_cur + 1) && *(formatter.fmt_cur + 1) != '%';
 980            ++formatter.fmt_cur) {}
 981       retval = formatter.format();
 982       dfsan_set_label(0, formatter.str_cur(),
 983                       formatter.num_written_bytes(retval));
 984     } else {
 985       // Conversion directive. Consume all the characters until a conversion
 986       // specifier or the end of the string.
 987       bool end_fmt = false;
 988       for (; *formatter.fmt_cur && !end_fmt; ) {
 989         switch (*++formatter.fmt_cur) {
 990         case 'd':
 991         case 'i':
 992         case 'o':
 993         case 'u':
 994         case 'x':
 995         case 'X':
 996           switch (*(formatter.fmt_cur - 1)) {
 997           case 'h':
 998             // Also covers the 'hh' case (since the size of the arg is still
 999             // an int).
1000             retval = formatter.format(va_arg(ap, int));
1001             break;
1002           case 'l':
1003             if (formatter.fmt_cur - formatter.fmt_start >= 2 &&
1004                 *(formatter.fmt_cur - 2) == 'l') {
1005               retval = formatter.format(va_arg(ap, long long int));
1006             } else {
1007               retval = formatter.format(va_arg(ap, long int));
1008             }
1009             break;
1010           case 'q':
1011             retval = formatter.format(va_arg(ap, long long int));
1012             break;
1013           case 'j':
1014             retval = formatter.format(va_arg(ap, intmax_t));
1015             break;
1016           case 'z':
1017           case 't':
1018             retval = formatter.format(va_arg(ap, size_t));
1019             break;
1020           default:
1021             retval = formatter.format(va_arg(ap, int));
1022           }
1023           dfsan_set_label(*va_labels++, formatter.str_cur(),
1024                           formatter.num_written_bytes(retval));
1025           end_fmt = true;
1026           break;
1027
1028         case 'a':
1029         case 'A':
1030         case 'e':
1031         case 'E':
1032         case 'f':
1033         case 'F':
1034         case 'g':
1035         case 'G':
1036           if (*(formatter.fmt_cur - 1) == 'L') {
1037             retval = formatter.format(va_arg(ap, long double));
1038           } else {
1039             retval = formatter.format(va_arg(ap, double));
1040           }
1041           dfsan_set_label(*va_labels++, formatter.str_cur(),
1042                           formatter.num_written_bytes(retval));
1043           end_fmt = true;
1044           break;
1045
1046         case 'c':
1047           retval = formatter.format(va_arg(ap, int));
1048           dfsan_set_label(*va_labels++, formatter.str_cur(),
1049                           formatter.num_written_bytes(retval));
1050           end_fmt = true;
1051           break;
1052
1053         case 's': {
1054           char *arg = va_arg(ap, char *);
1055           retval = formatter.format(arg);
1056           va_labels++;
1057           internal_memcpy(shadow_for(formatter.str_cur()), shadow_for(arg),
1058                           sizeof(dfsan_label) *
1059                               formatter.num_written_bytes(retval));
1060           end_fmt = true;
1061           break;
1062         }
1063
1064         case 'p':
1065           retval = formatter.format(va_arg(ap, void *));
1066           dfsan_set_label(*va_labels++, formatter.str_cur(),
1067                           formatter.num_written_bytes(retval));
1068           end_fmt = true;
1069           break;
1070
1071         case 'n': {
1072           int *ptr = va_arg(ap, int *);
1073           *ptr = (int)formatter.str_off;
1074           va_labels++;
1075           dfsan_set_label(0, ptr, sizeof(ptr));
1076           end_fmt = true;
1077           break;
1078         }
1079
1080         case '%':
1081           retval = formatter.format();
1082           dfsan_set_label(0, formatter.str_cur(),
1083                           formatter.num_written_bytes(retval));
1084           end_fmt = true;
1085           break;
1086
1087         case '*':
1088           formatter.width = va_arg(ap, int);
1089           va_labels++;
1090           break;
1091
1092         default:
1093           break;
1094         }
1095       }
1096     }
1097
1098     if (retval < 0) {
1099       return retval;
1100     }
1101
1102     formatter.fmt_cur++;
1103     formatter.str_off += retval;
1104   }
1105
1106   *ret_label = 0;
1107
1108   // Number of bytes written in total.
1109   return formatter.str_off;
1110 }
1111
1112 extern "C" {
1113 SANITIZER_INTERFACE_ATTRIBUTE
1114 int __dfsw_sprintf(char *str, const char *format, dfsan_label str_label,
1115                    dfsan_label format_label, dfsan_label *va_labels,
1116                    dfsan_label *ret_label, ...) {
1117   va_list ap;
1118   va_start(ap, ret_label);
1119   int ret = format_buffer(str, ~0ul, format, va_labels, ret_label, ap);
1120   va_end(ap);
1121   return ret;
1122 }
1123
1124 SANITIZER_INTERFACE_ATTRIBUTE
1125 int __dfsw_snprintf(char *str, size_t size, const char *format,
1126                     dfsan_label str_label, dfsan_label size_label,
1127                     dfsan_label format_label, dfsan_label *va_labels,
1128                     dfsan_label *ret_label, ...) {
1129   va_list ap;
1130   va_start(ap, ret_label);
1131   int ret = format_buffer(str, size, format, va_labels, ret_label, ap);
1132   va_end(ap);
1133   return ret;
1134 }
1135
1136 // Default empty implementations (weak). Users should redefine them.
1137 SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_trace_pc_guard, u32 *) {}
1138 SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_trace_pc_guard_init, u32 *,
1139                              u32 *) {}
1140 SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_pcs_init, void) {}
1141 SANITIZER_INTERFACE_WEAK_DEF(void, __sanitizer_cov_trace_pc_indir, void) {}
1142
1143 SANITIZER_INTERFACE_WEAK_DEF(void, __dfsw___sanitizer_cov_trace_cmp, void) {}
1144 SANITIZER_INTERFACE_WEAK_DEF(void, __dfsw___sanitizer_cov_trace_cmp1, void) {}
1145 SANITIZER_INTERFACE_WEAK_DEF(void, __dfsw___sanitizer_cov_trace_cmp2, void) {}
1146 SANITIZER_INTERFACE_WEAK_DEF(void, __dfsw___sanitizer_cov_trace_cmp4, void) {}
1147 SANITIZER_INTERFACE_WEAK_DEF(void, __dfsw___sanitizer_cov_trace_cmp8, void) {}
1148 SANITIZER_INTERFACE_WEAK_DEF(void, __dfsw___sanitizer_cov_trace_const_cmp1,
1149                              void) {}
1150 SANITIZER_INTERFACE_WEAK_DEF(void, __dfsw___sanitizer_cov_trace_const_cmp2,
1151                              void) {}
1152 SANITIZER_INTERFACE_WEAK_DEF(void, __dfsw___sanitizer_cov_trace_const_cmp4,
1153                              void) {}
1154 SANITIZER_INTERFACE_WEAK_DEF(void, __dfsw___sanitizer_cov_trace_const_cmp8,
1155                              void) {}
1156 SANITIZER_INTERFACE_WEAK_DEF(void, __dfsw___sanitizer_cov_trace_switch, void) {}
1157 }  // extern "C"