libsanitizer/sanitizer_common/sanitizer_posix_libcdep.cc

   1 //===-- sanitizer_posix_libcdep.cc ----------------------------------------===//
   2 //
   3 // This file is distributed under the University of Illinois Open Source
   4 // License. See LICENSE.TXT for details.
   5 //
   6 //===----------------------------------------------------------------------===//
   7 //
   8 // This file is shared between AddressSanitizer and ThreadSanitizer
   9 // run-time libraries and implements libc-dependent POSIX-specific functions
  10 // from sanitizer_libc.h.
  11 //===----------------------------------------------------------------------===//
  12
  13 #include "sanitizer_platform.h"
  14
  15 #if SANITIZER_POSIX
  16
  17 #include "sanitizer_common.h"
  18 #include "sanitizer_flags.h"
  19 #include "sanitizer_platform_limits_netbsd.h"
  20 #include "sanitizer_platform_limits_openbsd.h"
  21 #include "sanitizer_platform_limits_posix.h"
  22 #include "sanitizer_platform_limits_solaris.h"
  23 #include "sanitizer_posix.h"
  24 #include "sanitizer_procmaps.h"
  25
  26 #include <errno.h>
  27 #include <fcntl.h>
  28 #include <pthread.h>
  29 #include <signal.h>
  30 #include <stdlib.h>
  31 #include <sys/mman.h>
  32 #include <sys/resource.h>
  33 #include <sys/stat.h>
  34 #include <sys/time.h>
  35 #include <sys/types.h>
  36 #include <sys/wait.h>
  37 #include <unistd.h>
  38
  39 #if SANITIZER_FREEBSD
  40 // The MAP_NORESERVE define has been removed in FreeBSD 11.x, and even before
  41 // that, it was never implemented.  So just define it to zero.
  42 #undef MAP_NORESERVE
  43 #define MAP_NORESERVE 0
  44 #endif
  45
  46 typedef void (*sa_sigaction_t)(int, siginfo_t *, void *);
  47
  48 namespace __sanitizer {
  49
  50 u32 GetUid() {
  51   return getuid();
  52 }
  53
  54 uptr GetThreadSelf() {
  55   return (uptr)pthread_self();
  56 }
  57
  58 void ReleaseMemoryPagesToOS(uptr beg, uptr end) {
  59   uptr page_size = GetPageSizeCached();
  60   uptr beg_aligned = RoundUpTo(beg, page_size);
  61   uptr end_aligned = RoundDownTo(end, page_size);
  62   if (beg_aligned < end_aligned)
  63     // In the default Solaris compilation environment, madvise() is declared
  64     // to take a caddr_t arg; casting it to void * results in an invalid
  65     // conversion error, so use char * instead.
  66     madvise((char *)beg_aligned, end_aligned - beg_aligned,
  67             SANITIZER_MADVISE_DONTNEED);
  68 }
  69
  70 bool NoHugePagesInRegion(uptr addr, uptr size) {
  71 #ifdef MADV_NOHUGEPAGE  // May not be defined on old systems.
  72   return madvise((void *)addr, size, MADV_NOHUGEPAGE) == 0;
  73 #else
  74   return true;
  75 #endif  // MADV_NOHUGEPAGE
  76 }
  77
  78 bool DontDumpShadowMemory(uptr addr, uptr length) {
  79 #if defined(MADV_DONTDUMP)
  80   return madvise((void *)addr, length, MADV_DONTDUMP) == 0;
  81 #elif defined(MADV_NOCORE)
  82   return madvise((void *)addr, length, MADV_NOCORE) == 0;
  83 #else
  84   return true;
  85 #endif  // MADV_DONTDUMP
  86 }
  87
  88 static rlim_t getlim(int res) {
  89   rlimit rlim;
  90   CHECK_EQ(0, getrlimit(res, &rlim));
  91   return rlim.rlim_cur;
  92 }
  93
  94 static void setlim(int res, rlim_t lim) {
  95   // The following magic is to prevent clang from replacing it with memset.
  96   volatile struct rlimit rlim;
  97   rlim.rlim_cur = lim;
  98   rlim.rlim_max = lim;
  99   if (setrlimit(res, const_cast<struct rlimit *>(&rlim))) {
 100     Report("ERROR: %s setrlimit() failed %d\n", SanitizerToolName, errno);
 101     Die();
 102   }
 103 }
 104
 105 void DisableCoreDumperIfNecessary() {
 106   if (common_flags()->disable_coredump) {
 107     setlim(RLIMIT_CORE, 0);
 108   }
 109 }
 110
 111 bool StackSizeIsUnlimited() {
 112   rlim_t stack_size = getlim(RLIMIT_STACK);
 113   return (stack_size == RLIM_INFINITY);
 114 }
 115
 116 uptr GetStackSizeLimitInBytes() {
 117   return (uptr)getlim(RLIMIT_STACK);
 118 }
 119
 120 void SetStackSizeLimitInBytes(uptr limit) {
 121   setlim(RLIMIT_STACK, (rlim_t)limit);
 122   CHECK(!StackSizeIsUnlimited());
 123 }
 124
 125 bool AddressSpaceIsUnlimited() {
 126   rlim_t as_size = getlim(RLIMIT_AS);
 127   return (as_size == RLIM_INFINITY);
 128 }
 129
 130 void SetAddressSpaceUnlimited() {
 131   setlim(RLIMIT_AS, RLIM_INFINITY);
 132   CHECK(AddressSpaceIsUnlimited());
 133 }
 134
 135 void SleepForSeconds(int seconds) {
 136   sleep(seconds);
 137 }
 138
 139 void SleepForMillis(int millis) {
 140   usleep(millis * 1000);
 141 }
 142
 143 void Abort() {
 144 #if !SANITIZER_GO
 145   // If we are handling SIGABRT, unhandle it first.
 146   // TODO(vitalybuka): Check if handler belongs to sanitizer.
 147   if (GetHandleSignalMode(SIGABRT) != kHandleSignalNo) {
 148     struct sigaction sigact;
 149     internal_memset(&sigact, 0, sizeof(sigact));
 150     sigact.sa_sigaction = (sa_sigaction_t)SIG_DFL;
 151     internal_sigaction(SIGABRT, &sigact, nullptr);
 152   }
 153 #endif
 154
 155   abort();
 156 }
 157
 158 int Atexit(void (*function)(void)) {
 159 #if !SANITIZER_GO
 160   return atexit(function);
 161 #else
 162   return 0;
 163 #endif
 164 }
 165
 166 bool SupportsColoredOutput(fd_t fd) {
 167   return isatty(fd) != 0;
 168 }
 169
 170 #if !SANITIZER_GO
 171 // TODO(glider): different tools may require different altstack size.
 172 static const uptr kAltStackSize = SIGSTKSZ * 4;  // SIGSTKSZ is not enough.
 173
 174 void SetAlternateSignalStack() {
 175   stack_t altstack, oldstack;
 176   CHECK_EQ(0, sigaltstack(nullptr, &oldstack));
 177   // If the alternate stack is already in place, do nothing.
 178   // Android always sets an alternate stack, but it's too small for us.
 179   if (!SANITIZER_ANDROID && !(oldstack.ss_flags & SS_DISABLE)) return;
 180   // TODO(glider): the mapped stack should have the MAP_STACK flag in the
 181   // future. It is not required by man 2 sigaltstack now (they're using
 182   // malloc()).
 183   void* base = MmapOrDie(kAltStackSize, __func__);
 184   altstack.ss_sp = (char*) base;
 185   altstack.ss_flags = 0;
 186   altstack.ss_size = kAltStackSize;
 187   CHECK_EQ(0, sigaltstack(&altstack, nullptr));
 188 }
 189
 190 void UnsetAlternateSignalStack() {
 191   stack_t altstack, oldstack;
 192   altstack.ss_sp = nullptr;
 193   altstack.ss_flags = SS_DISABLE;
 194   altstack.ss_size = kAltStackSize;  // Some sane value required on Darwin.
 195   CHECK_EQ(0, sigaltstack(&altstack, &oldstack));
 196   UnmapOrDie(oldstack.ss_sp, oldstack.ss_size);
 197 }
 198
 199 static void MaybeInstallSigaction(int signum,
 200                                   SignalHandlerType handler) {
 201   if (GetHandleSignalMode(signum) == kHandleSignalNo) return;
 202
 203   struct sigaction sigact;
 204   internal_memset(&sigact, 0, sizeof(sigact));
 205   sigact.sa_sigaction = (sa_sigaction_t)handler;
 206   // Do not block the signal from being received in that signal's handler.
 207   // Clients are responsible for handling this correctly.
 208   sigact.sa_flags = SA_SIGINFO | SA_NODEFER;
 209   if (common_flags()->use_sigaltstack) sigact.sa_flags |= SA_ONSTACK;
 210   CHECK_EQ(0, internal_sigaction(signum, &sigact, nullptr));
 211   VReport(1, "Installed the sigaction for signal %d\n", signum);
 212 }
 213
 214 void InstallDeadlySignalHandlers(SignalHandlerType handler) {
 215   // Set the alternate signal stack for the main thread.
 216   // This will cause SetAlternateSignalStack to be called twice, but the stack
 217   // will be actually set only once.
 218   if (common_flags()->use_sigaltstack) SetAlternateSignalStack();
 219   MaybeInstallSigaction(SIGSEGV, handler);
 220   MaybeInstallSigaction(SIGBUS, handler);
 221   MaybeInstallSigaction(SIGABRT, handler);
 222   MaybeInstallSigaction(SIGFPE, handler);
 223   MaybeInstallSigaction(SIGILL, handler);
 224   MaybeInstallSigaction(SIGTRAP, handler);
 225 }
 226
 227 bool SignalContext::IsStackOverflow() const {
 228   // Access at a reasonable offset above SP, or slightly below it (to account
 229   // for x86_64 or PowerPC redzone, ARM push of multiple registers, etc) is
 230   // probably a stack overflow.
 231 #ifdef __s390__
 232   // On s390, the fault address in siginfo points to start of the page, not
 233   // to the precise word that was accessed.  Mask off the low bits of sp to
 234   // take it into account.
 235   bool IsStackAccess = addr >= (sp & ~0xFFF) && addr < sp + 0xFFFF;
 236 #else
 237   // Let's accept up to a page size away from top of stack. Things like stack
 238   // probing can trigger accesses with such large offsets.
 239   bool IsStackAccess = addr + GetPageSizeCached() > sp && addr < sp + 0xFFFF;
 240 #endif
 241
 242 #if __powerpc__
 243   // Large stack frames can be allocated with e.g.
 244   //   lis r0,-10000
 245   //   stdux r1,r1,r0 # store sp to [sp-10000] and update sp by -10000
 246   // If the store faults then sp will not have been updated, so test above
 247   // will not work, because the fault address will be more than just "slightly"
 248   // below sp.
 249   if (!IsStackAccess && IsAccessibleMemoryRange(pc, 4)) {
 250     u32 inst = *(unsigned *)pc;
 251     u32 ra = (inst >> 16) & 0x1F;
 252     u32 opcd = inst >> 26;
 253     u32 xo = (inst >> 1) & 0x3FF;
 254     // Check for store-with-update to sp. The instructions we accept are:
 255     //   stbu rs,d(ra)          stbux rs,ra,rb
 256     //   sthu rs,d(ra)          sthux rs,ra,rb
 257     //   stwu rs,d(ra)          stwux rs,ra,rb
 258     //   stdu rs,ds(ra)         stdux rs,ra,rb
 259     // where ra is r1 (the stack pointer).
 260     if (ra == 1 &&
 261         (opcd == 39 || opcd == 45 || opcd == 37 || opcd == 62 ||
 262          (opcd == 31 && (xo == 247 || xo == 439 || xo == 183 || xo == 181))))
 263       IsStackAccess = true;
 264   }
 265 #endif  // __powerpc__
 266
 267   // We also check si_code to filter out SEGV caused by something else other
 268   // then hitting the guard page or unmapped memory, like, for example,
 269   // unaligned memory access.
 270   auto si = static_cast<const siginfo_t *>(siginfo);
 271   return IsStackAccess &&
 272          (si->si_code == si_SEGV_MAPERR || si->si_code == si_SEGV_ACCERR);
 273 }
 274
 275 #endif  // SANITIZER_GO
 276
 277 bool IsAccessibleMemoryRange(uptr beg, uptr size) {
 278   uptr page_size = GetPageSizeCached();
 279   // Checking too large memory ranges is slow.
 280   CHECK_LT(size, page_size * 10);
 281   int sock_pair[2];
 282   if (pipe(sock_pair))
 283     return false;
 284   uptr bytes_written =
 285       internal_write(sock_pair[1], reinterpret_cast<void *>(beg), size);
 286   int write_errno;
 287   bool result;
 288   if (internal_iserror(bytes_written, &write_errno)) {
 289     CHECK_EQ(EFAULT, write_errno);
 290     result = false;
 291   } else {
 292     result = (bytes_written == size);
 293   }
 294   internal_close(sock_pair[0]);
 295   internal_close(sock_pair[1]);
 296   return result;
 297 }
 298
 299 void PlatformPrepareForSandboxing(__sanitizer_sandbox_arguments *args) {
 300   // Some kinds of sandboxes may forbid filesystem access, so we won't be able
 301   // to read the file mappings from /proc/self/maps. Luckily, neither the
 302   // process will be able to load additional libraries, so it's fine to use the
 303   // cached mappings.
 304   MemoryMappingLayout::CacheMemoryMappings();
 305 }
 306
 307 #if SANITIZER_ANDROID || SANITIZER_GO
 308 int GetNamedMappingFd(const char *name, uptr size) {
 309   return -1;
 310 }
 311 #else
 312 int GetNamedMappingFd(const char *name, uptr size) {
 313   if (!common_flags()->decorate_proc_maps)
 314     return -1;
 315   char shmname[200];
 316   CHECK(internal_strlen(name) < sizeof(shmname) - 10);
 317   internal_snprintf(shmname, sizeof(shmname), "%zu [%s]", internal_getpid(),
 318                     name);
 319   int fd = shm_open(shmname, O_RDWR | O_CREAT | O_TRUNC, S_IRWXU);
 320   CHECK_GE(fd, 0);
 321   int res = internal_ftruncate(fd, size);
 322   CHECK_EQ(0, res);
 323   res = shm_unlink(shmname);
 324   CHECK_EQ(0, res);
 325   return fd;
 326 }
 327 #endif
 328
 329 bool MmapFixedNoReserve(uptr fixed_addr, uptr size, const char *name) {
 330   int fd = name ? GetNamedMappingFd(name, size) : -1;
 331   unsigned flags = MAP_PRIVATE | MAP_FIXED | MAP_NORESERVE;
 332   if (fd == -1) flags |= MAP_ANON;
 333
 334   uptr PageSize = GetPageSizeCached();
 335   uptr p = internal_mmap((void *)(fixed_addr & ~(PageSize - 1)),
 336                          RoundUpTo(size, PageSize), PROT_READ | PROT_WRITE,
 337                          flags, fd, 0);
 338   int reserrno;
 339   if (internal_iserror(p, &reserrno)) {
 340     Report("ERROR: %s failed to "
 341            "allocate 0x%zx (%zd) bytes at address %zx (errno: %d)\n",
 342            SanitizerToolName, size, size, fixed_addr, reserrno);
 343     return false;
 344   }
 345   IncreaseTotalMmap(size);
 346   return true;
 347 }
 348
 349 uptr ReservedAddressRange::Init(uptr size, const char *name, uptr fixed_addr) {
 350   // We don't pass `name` along because, when you enable `decorate_proc_maps`
 351   // AND actually use a named mapping AND are using a sanitizer intercepting
 352   // `open` (e.g. TSAN, ESAN), then you'll get a failure during initialization.
 353   // TODO(flowerhack): Fix the implementation of GetNamedMappingFd to solve
 354   // this problem.
 355   base_ = fixed_addr ? MmapFixedNoAccess(fixed_addr, size) : MmapNoAccess(size);
 356   size_ = size;
 357   name_ = name;
 358   (void)os_handle_;  // unsupported
 359   return reinterpret_cast<uptr>(base_);
 360 }
 361
 362 // Uses fixed_addr for now.
 363 // Will use offset instead once we've implemented this function for real.
 364 uptr ReservedAddressRange::Map(uptr fixed_addr, uptr size) {
 365   return reinterpret_cast<uptr>(MmapFixedOrDieOnFatalError(fixed_addr, size));
 366 }
 367
 368 uptr ReservedAddressRange::MapOrDie(uptr fixed_addr, uptr size) {
 369   return reinterpret_cast<uptr>(MmapFixedOrDie(fixed_addr, size));
 370 }
 371
 372 void ReservedAddressRange::Unmap(uptr addr, uptr size) {
 373   CHECK_LE(size, size_);
 374   if (addr == reinterpret_cast<uptr>(base_))
 375     // If we unmap the whole range, just null out the base.
 376     base_ = (size == size_) ? nullptr : reinterpret_cast<void*>(addr + size);
 377   else
 378     CHECK_EQ(addr + size, reinterpret_cast<uptr>(base_) + size_);
 379   size_ -= size;
 380   UnmapOrDie(reinterpret_cast<void*>(addr), size);
 381 }
 382
 383 void *MmapFixedNoAccess(uptr fixed_addr, uptr size, const char *name) {
 384   int fd = name ? GetNamedMappingFd(name, size) : -1;
 385   unsigned flags = MAP_PRIVATE | MAP_FIXED | MAP_NORESERVE;
 386   if (fd == -1) flags |= MAP_ANON;
 387
 388   return (void *)internal_mmap((void *)fixed_addr, size, PROT_NONE, flags, fd,
 389                                0);
 390 }
 391
 392 void *MmapNoAccess(uptr size) {
 393   unsigned flags = MAP_PRIVATE | MAP_ANON | MAP_NORESERVE;
 394   return (void *)internal_mmap(nullptr, size, PROT_NONE, flags, -1, 0);
 395 }
 396
 397 // This function is defined elsewhere if we intercepted pthread_attr_getstack.
 398 extern "C" {
 399 SANITIZER_WEAK_ATTRIBUTE int
 400 real_pthread_attr_getstack(void *attr, void **addr, size_t *size);
 401 } // extern "C"
 402
 403 int my_pthread_attr_getstack(void *attr, void **addr, uptr *size) {
 404 #if !SANITIZER_GO && !SANITIZER_MAC
 405   if (&real_pthread_attr_getstack)
 406     return real_pthread_attr_getstack((pthread_attr_t *)attr, addr,
 407                                       (size_t *)size);
 408 #endif
 409   return pthread_attr_getstack((pthread_attr_t *)attr, addr, (size_t *)size);
 410 }
 411
 412 #if !SANITIZER_GO
 413 void AdjustStackSize(void *attr_) {
 414   pthread_attr_t *attr = (pthread_attr_t *)attr_;
 415   uptr stackaddr = 0;
 416   uptr stacksize = 0;
 417   my_pthread_attr_getstack(attr, (void**)&stackaddr, &stacksize);
 418   // GLibC will return (0 - stacksize) as the stack address in the case when
 419   // stacksize is set, but stackaddr is not.
 420   bool stack_set = (stackaddr != 0) && (stackaddr + stacksize != 0);
 421   // We place a lot of tool data into TLS, account for that.
 422   const uptr minstacksize = GetTlsSize() + 128*1024;
 423   if (stacksize < minstacksize) {
 424     if (!stack_set) {
 425       if (stacksize != 0) {
 426         VPrintf(1, "Sanitizer: increasing stacksize %zu->%zu\n", stacksize,
 427                 minstacksize);
 428         pthread_attr_setstacksize(attr, minstacksize);
 429       }
 430     } else {
 431       Printf("Sanitizer: pre-allocated stack size is insufficient: "
 432              "%zu < %zu\n", stacksize, minstacksize);
 433       Printf("Sanitizer: pthread_create is likely to fail.\n");
 434     }
 435   }
 436 }
 437 #endif // !SANITIZER_GO
 438
 439 pid_t StartSubprocess(const char *program, const char *const argv[],
 440                       fd_t stdin_fd, fd_t stdout_fd, fd_t stderr_fd) {
 441   auto file_closer = at_scope_exit([&] {
 442     if (stdin_fd != kInvalidFd) {
 443       internal_close(stdin_fd);
 444     }
 445     if (stdout_fd != kInvalidFd) {
 446       internal_close(stdout_fd);
 447     }
 448     if (stderr_fd != kInvalidFd) {
 449       internal_close(stderr_fd);
 450     }
 451   });
 452
 453   int pid = internal_fork();
 454
 455   if (pid < 0) {
 456     int rverrno;
 457     if (internal_iserror(pid, &rverrno)) {
 458       Report("WARNING: failed to fork (errno %d)\n", rverrno);
 459     }
 460     return pid;
 461   }
 462
 463   if (pid == 0) {
 464     // Child subprocess
 465     if (stdin_fd != kInvalidFd) {
 466       internal_close(STDIN_FILENO);
 467       internal_dup2(stdin_fd, STDIN_FILENO);
 468       internal_close(stdin_fd);
 469     }
 470     if (stdout_fd != kInvalidFd) {
 471       internal_close(STDOUT_FILENO);
 472       internal_dup2(stdout_fd, STDOUT_FILENO);
 473       internal_close(stdout_fd);
 474     }
 475     if (stderr_fd != kInvalidFd) {
 476       internal_close(STDERR_FILENO);
 477       internal_dup2(stderr_fd, STDERR_FILENO);
 478       internal_close(stderr_fd);
 479     }
 480
 481     for (int fd = sysconf(_SC_OPEN_MAX); fd > 2; fd--) internal_close(fd);
 482
 483     execv(program, const_cast<char **>(&argv[0]));
 484     internal__exit(1);
 485   }
 486
 487   return pid;
 488 }
 489
 490 bool IsProcessRunning(pid_t pid) {
 491   int process_status;
 492   uptr waitpid_status = internal_waitpid(pid, &process_status, WNOHANG);
 493   int local_errno;
 494   if (internal_iserror(waitpid_status, &local_errno)) {
 495     VReport(1, "Waiting on the process failed (errno %d).\n", local_errno);
 496     return false;
 497   }
 498   return waitpid_status == 0;
 499 }
 500
 501 int WaitForProcess(pid_t pid) {
 502   int process_status;
 503   uptr waitpid_status = internal_waitpid(pid, &process_status, 0);
 504   int local_errno;
 505   if (internal_iserror(waitpid_status, &local_errno)) {
 506     VReport(1, "Waiting on the process failed (errno %d).\n", local_errno);
 507     return -1;
 508   }
 509   return process_status;
 510 }
 511
 512 bool IsStateDetached(int state) {
 513   return state == PTHREAD_CREATE_DETACHED;
 514 }
 515
 516 } // namespace __sanitizer
 517
 518 #endif // SANITIZER_POSIX