compiler-rt/lib/sanitizer_common/sanitizer_posix_libcdep.cpp

   1 //===-- sanitizer_posix_libcdep.cpp ---------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // This file is shared between AddressSanitizer and ThreadSanitizer
  10 // run-time libraries and implements libc-dependent POSIX-specific functions
  11 // from sanitizer_libc.h.
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "sanitizer_platform.h"
  15
  16 #if SANITIZER_POSIX
  17
  18 #include "sanitizer_common.h"
  19 #include "sanitizer_flags.h"
  20 #include "sanitizer_platform_limits_netbsd.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     internal_madvise(beg_aligned, end_aligned - beg_aligned,
  64                      SANITIZER_MADVISE_DONTNEED);
  65 }
  66
  67 void SetShadowRegionHugePageMode(uptr addr, uptr size) {
  68 #ifdef MADV_NOHUGEPAGE  // May not be defined on old systems.
  69   if (common_flags()->no_huge_pages_for_shadow)
  70     internal_madvise(addr, size, MADV_NOHUGEPAGE);
  71   else
  72     internal_madvise(addr, size, MADV_HUGEPAGE);
  73 #endif  // MADV_NOHUGEPAGE
  74 }
  75
  76 bool DontDumpShadowMemory(uptr addr, uptr length) {
  77 #if defined(MADV_DONTDUMP)
  78   return internal_madvise(addr, length, MADV_DONTDUMP) == 0;
  79 #elif defined(MADV_NOCORE)
  80   return internal_madvise(addr, length, MADV_NOCORE) == 0;
  81 #else
  82   return true;
  83 #endif  // MADV_DONTDUMP
  84 }
  85
  86 static rlim_t getlim(int res) {
  87   rlimit rlim;
  88   CHECK_EQ(0, getrlimit(res, &rlim));
  89   return rlim.rlim_cur;
  90 }
  91
  92 static void setlim(int res, rlim_t lim) {
  93   struct rlimit rlim;
  94   if (getrlimit(res, const_cast<struct rlimit *>(&rlim))) {
  95     Report("ERROR: %s getrlimit() failed %d\n", SanitizerToolName, errno);
  96     Die();
  97   }
  98   rlim.rlim_cur = 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 void SetStackSizeLimitInBytes(uptr limit) {
 117   setlim(RLIMIT_STACK, (rlim_t)limit);
 118   CHECK(!StackSizeIsUnlimited());
 119 }
 120
 121 bool AddressSpaceIsUnlimited() {
 122   rlim_t as_size = getlim(RLIMIT_AS);
 123   return (as_size == RLIM_INFINITY);
 124 }
 125
 126 void SetAddressSpaceUnlimited() {
 127   setlim(RLIMIT_AS, RLIM_INFINITY);
 128   CHECK(AddressSpaceIsUnlimited());
 129 }
 130
 131 void Abort() {
 132 #if !SANITIZER_GO
 133   // If we are handling SIGABRT, unhandle it first.
 134   // TODO(vitalybuka): Check if handler belongs to sanitizer.
 135   if (GetHandleSignalMode(SIGABRT) != kHandleSignalNo) {
 136     struct sigaction sigact;
 137     internal_memset(&sigact, 0, sizeof(sigact));
 138     sigact.sa_handler = SIG_DFL;
 139     internal_sigaction(SIGABRT, &sigact, nullptr);
 140   }
 141 #endif
 142
 143   abort();
 144 }
 145
 146 int Atexit(void (*function)(void)) {
 147 #if !SANITIZER_GO
 148   return atexit(function);
 149 #else
 150   return 0;
 151 #endif
 152 }
 153
 154 bool CreateDir(const char *pathname) { return mkdir(pathname, 0755) == 0; }
 155
 156 bool SupportsColoredOutput(fd_t fd) {
 157   return isatty(fd) != 0;
 158 }
 159
 160 #if !SANITIZER_GO
 161 // TODO(glider): different tools may require different altstack size.
 162 static uptr GetAltStackSize() {
 163   // Note: since GLIBC_2.31, SIGSTKSZ may be a function call, so this may be
 164   // more costly that you think. However GetAltStackSize is only call 2-3 times
 165   // per thread so don't cache the evaluation.
 166   return SIGSTKSZ * 4;
 167 }
 168
 169 void SetAlternateSignalStack() {
 170   stack_t altstack, oldstack;
 171   CHECK_EQ(0, sigaltstack(nullptr, &oldstack));
 172   // If the alternate stack is already in place, do nothing.
 173   // Android always sets an alternate stack, but it's too small for us.
 174   if (!SANITIZER_ANDROID && !(oldstack.ss_flags & SS_DISABLE)) return;
 175   // TODO(glider): the mapped stack should have the MAP_STACK flag in the
 176   // future. It is not required by man 2 sigaltstack now (they're using
 177   // malloc()).
 178   altstack.ss_size = GetAltStackSize();
 179   altstack.ss_sp = (char *)MmapOrDie(altstack.ss_size, __func__);
 180   altstack.ss_flags = 0;
 181   CHECK_EQ(0, sigaltstack(&altstack, nullptr));
 182 }
 183
 184 void UnsetAlternateSignalStack() {
 185   stack_t altstack, oldstack;
 186   altstack.ss_sp = nullptr;
 187   altstack.ss_flags = SS_DISABLE;
 188   altstack.ss_size = GetAltStackSize();  // Some sane value required on Darwin.
 189   CHECK_EQ(0, sigaltstack(&altstack, &oldstack));
 190   UnmapOrDie(oldstack.ss_sp, oldstack.ss_size);
 191 }
 192
 193 static void MaybeInstallSigaction(int signum,
 194                                   SignalHandlerType handler) {
 195   if (GetHandleSignalMode(signum) == kHandleSignalNo) return;
 196
 197   struct sigaction sigact;
 198   internal_memset(&sigact, 0, sizeof(sigact));
 199   sigact.sa_sigaction = (sa_sigaction_t)handler;
 200   // Do not block the signal from being received in that signal's handler.
 201   // Clients are responsible for handling this correctly.
 202   sigact.sa_flags = SA_SIGINFO | SA_NODEFER;
 203   if (common_flags()->use_sigaltstack) sigact.sa_flags |= SA_ONSTACK;
 204   CHECK_EQ(0, internal_sigaction(signum, &sigact, nullptr));
 205   VReport(1, "Installed the sigaction for signal %d\n", signum);
 206 }
 207
 208 void InstallDeadlySignalHandlers(SignalHandlerType handler) {
 209   // Set the alternate signal stack for the main thread.
 210   // This will cause SetAlternateSignalStack to be called twice, but the stack
 211   // will be actually set only once.
 212   if (common_flags()->use_sigaltstack) SetAlternateSignalStack();
 213   MaybeInstallSigaction(SIGSEGV, handler);
 214   MaybeInstallSigaction(SIGBUS, handler);
 215   MaybeInstallSigaction(SIGABRT, handler);
 216   MaybeInstallSigaction(SIGFPE, handler);
 217   MaybeInstallSigaction(SIGILL, handler);
 218   MaybeInstallSigaction(SIGTRAP, handler);
 219 }
 220
 221 bool SignalContext::IsStackOverflow() const {
 222   // Access at a reasonable offset above SP, or slightly below it (to account
 223   // for x86_64 or PowerPC redzone, ARM push of multiple registers, etc) is
 224   // probably a stack overflow.
 225 #ifdef __s390__
 226   // On s390, the fault address in siginfo points to start of the page, not
 227   // to the precise word that was accessed.  Mask off the low bits of sp to
 228   // take it into account.
 229   bool IsStackAccess = addr >= (sp & ~0xFFF) && addr < sp + 0xFFFF;
 230 #else
 231   // Let's accept up to a page size away from top of stack. Things like stack
 232   // probing can trigger accesses with such large offsets.
 233   bool IsStackAccess = addr + GetPageSizeCached() > sp && addr < sp + 0xFFFF;
 234 #endif
 235
 236 #if __powerpc__
 237   // Large stack frames can be allocated with e.g.
 238   //   lis r0,-10000
 239   //   stdux r1,r1,r0 # store sp to [sp-10000] and update sp by -10000
 240   // If the store faults then sp will not have been updated, so test above
 241   // will not work, because the fault address will be more than just "slightly"
 242   // below sp.
 243   if (!IsStackAccess && IsAccessibleMemoryRange(pc, 4)) {
 244     u32 inst = *(unsigned *)pc;
 245     u32 ra = (inst >> 16) & 0x1F;
 246     u32 opcd = inst >> 26;
 247     u32 xo = (inst >> 1) & 0x3FF;
 248     // Check for store-with-update to sp. The instructions we accept are:
 249     //   stbu rs,d(ra)          stbux rs,ra,rb
 250     //   sthu rs,d(ra)          sthux rs,ra,rb
 251     //   stwu rs,d(ra)          stwux rs,ra,rb
 252     //   stdu rs,ds(ra)         stdux rs,ra,rb
 253     // where ra is r1 (the stack pointer).
 254     if (ra == 1 &&
 255         (opcd == 39 || opcd == 45 || opcd == 37 || opcd == 62 ||
 256          (opcd == 31 && (xo == 247 || xo == 439 || xo == 183 || xo == 181))))
 257       IsStackAccess = true;
 258   }
 259 #endif  // __powerpc__
 260
 261   // We also check si_code to filter out SEGV caused by something else other
 262   // then hitting the guard page or unmapped memory, like, for example,
 263   // unaligned memory access.
 264   auto si = static_cast<const siginfo_t *>(siginfo);
 265   return IsStackAccess &&
 266          (si->si_code == si_SEGV_MAPERR || si->si_code == si_SEGV_ACCERR);
 267 }
 268
 269 #endif  // SANITIZER_GO
 270
 271 bool IsAccessibleMemoryRange(uptr beg, uptr size) {
 272   uptr page_size = GetPageSizeCached();
 273   // Checking too large memory ranges is slow.
 274   CHECK_LT(size, page_size * 10);
 275   int sock_pair[2];
 276   if (pipe(sock_pair))
 277     return false;
 278   uptr bytes_written =
 279       internal_write(sock_pair[1], reinterpret_cast<void *>(beg), size);
 280   int write_errno;
 281   bool result;
 282   if (internal_iserror(bytes_written, &write_errno)) {
 283     CHECK_EQ(EFAULT, write_errno);
 284     result = false;
 285   } else {
 286     result = (bytes_written == size);
 287   }
 288   internal_close(sock_pair[0]);
 289   internal_close(sock_pair[1]);
 290   return result;
 291 }
 292
 293 void PlatformPrepareForSandboxing(void *args) {
 294   // Some kinds of sandboxes may forbid filesystem access, so we won't be able
 295   // to read the file mappings from /proc/self/maps. Luckily, neither the
 296   // process will be able to load additional libraries, so it's fine to use the
 297   // cached mappings.
 298   MemoryMappingLayout::CacheMemoryMappings();
 299 }
 300
 301 static bool MmapFixed(uptr fixed_addr, uptr size, int additional_flags,
 302                       const char *name) {
 303   size = RoundUpTo(size, GetPageSizeCached());
 304   fixed_addr = RoundDownTo(fixed_addr, GetPageSizeCached());
 305   uptr p =
 306       MmapNamed((void *)fixed_addr, size, PROT_READ | PROT_WRITE,
 307                 MAP_PRIVATE | MAP_FIXED | additional_flags | MAP_ANON, name);
 308   int reserrno;
 309   if (internal_iserror(p, &reserrno)) {
 310     Report("ERROR: %s failed to "
 311            "allocate 0x%zx (%zd) bytes at address %zx (errno: %d)\n",
 312            SanitizerToolName, size, size, fixed_addr, reserrno);
 313     return false;
 314   }
 315   IncreaseTotalMmap(size);
 316   return true;
 317 }
 318
 319 bool MmapFixedNoReserve(uptr fixed_addr, uptr size, const char *name) {
 320   return MmapFixed(fixed_addr, size, MAP_NORESERVE, name);
 321 }
 322
 323 bool MmapFixedSuperNoReserve(uptr fixed_addr, uptr size, const char *name) {
 324 #if SANITIZER_FREEBSD
 325   if (common_flags()->no_huge_pages_for_shadow)
 326     return MmapFixedNoReserve(fixed_addr, size, name);
 327   // MAP_NORESERVE is implicit with FreeBSD
 328   return MmapFixed(fixed_addr, size, MAP_ALIGNED_SUPER, name);
 329 #else
 330   bool r = MmapFixedNoReserve(fixed_addr, size, name);
 331   if (r)
 332     SetShadowRegionHugePageMode(fixed_addr, size);
 333   return r;
 334 #endif
 335 }
 336
 337 uptr ReservedAddressRange::Init(uptr size, const char *name, uptr fixed_addr) {
 338   base_ = fixed_addr ? MmapFixedNoAccess(fixed_addr, size, name)
 339                      : MmapNoAccess(size);
 340   size_ = size;
 341   name_ = name;
 342   (void)os_handle_;  // unsupported
 343   return reinterpret_cast<uptr>(base_);
 344 }
 345
 346 // Uses fixed_addr for now.
 347 // Will use offset instead once we've implemented this function for real.
 348 uptr ReservedAddressRange::Map(uptr fixed_addr, uptr size, const char *name) {
 349   return reinterpret_cast<uptr>(
 350       MmapFixedOrDieOnFatalError(fixed_addr, size, name));
 351 }
 352
 353 uptr ReservedAddressRange::MapOrDie(uptr fixed_addr, uptr size,
 354                                     const char *name) {
 355   return reinterpret_cast<uptr>(MmapFixedOrDie(fixed_addr, size, name));
 356 }
 357
 358 void ReservedAddressRange::Unmap(uptr addr, uptr size) {
 359   CHECK_LE(size, size_);
 360   if (addr == reinterpret_cast<uptr>(base_))
 361     // If we unmap the whole range, just null out the base.
 362     base_ = (size == size_) ? nullptr : reinterpret_cast<void*>(addr + size);
 363   else
 364     CHECK_EQ(addr + size, reinterpret_cast<uptr>(base_) + size_);
 365   size_ -= size;
 366   UnmapOrDie(reinterpret_cast<void*>(addr), size);
 367 }
 368
 369 void *MmapFixedNoAccess(uptr fixed_addr, uptr size, const char *name) {
 370   return (void *)MmapNamed((void *)fixed_addr, size, PROT_NONE,
 371                            MAP_PRIVATE | MAP_FIXED | MAP_NORESERVE | MAP_ANON,
 372                            name);
 373 }
 374
 375 void *MmapNoAccess(uptr size) {
 376   unsigned flags = MAP_PRIVATE | MAP_ANON | MAP_NORESERVE;
 377   return (void *)internal_mmap(nullptr, size, PROT_NONE, flags, -1, 0);
 378 }
 379
 380 // This function is defined elsewhere if we intercepted pthread_attr_getstack.
 381 extern "C" {
 382 SANITIZER_WEAK_ATTRIBUTE int
 383 real_pthread_attr_getstack(void *attr, void **addr, size_t *size);
 384 } // extern "C"
 385
 386 int my_pthread_attr_getstack(void *attr, void **addr, uptr *size) {
 387 #if !SANITIZER_GO && !SANITIZER_MAC
 388   if (&real_pthread_attr_getstack)
 389     return real_pthread_attr_getstack((pthread_attr_t *)attr, addr,
 390                                       (size_t *)size);
 391 #endif
 392   return pthread_attr_getstack((pthread_attr_t *)attr, addr, (size_t *)size);
 393 }
 394
 395 #if !SANITIZER_GO
 396 void AdjustStackSize(void *attr_) {
 397   pthread_attr_t *attr = (pthread_attr_t *)attr_;
 398   uptr stackaddr = 0;
 399   uptr stacksize = 0;
 400   my_pthread_attr_getstack(attr, (void**)&stackaddr, &stacksize);
 401   // GLibC will return (0 - stacksize) as the stack address in the case when
 402   // stacksize is set, but stackaddr is not.
 403   bool stack_set = (stackaddr != 0) && (stackaddr + stacksize != 0);
 404   // We place a lot of tool data into TLS, account for that.
 405   const uptr minstacksize = GetTlsSize() + 128*1024;
 406   if (stacksize < minstacksize) {
 407     if (!stack_set) {
 408       if (stacksize != 0) {
 409         VPrintf(1, "Sanitizer: increasing stacksize %zu->%zu\n", stacksize,
 410                 minstacksize);
 411         pthread_attr_setstacksize(attr, minstacksize);
 412       }
 413     } else {
 414       Printf("Sanitizer: pre-allocated stack size is insufficient: "
 415              "%zu < %zu\n", stacksize, minstacksize);
 416       Printf("Sanitizer: pthread_create is likely to fail.\n");
 417     }
 418   }
 419 }
 420 #endif // !SANITIZER_GO
 421
 422 pid_t StartSubprocess(const char *program, const char *const argv[],
 423                       const char *const envp[], fd_t stdin_fd, fd_t stdout_fd,
 424                       fd_t stderr_fd) {
 425   auto file_closer = at_scope_exit([&] {
 426     if (stdin_fd != kInvalidFd) {
 427       internal_close(stdin_fd);
 428     }
 429     if (stdout_fd != kInvalidFd) {
 430       internal_close(stdout_fd);
 431     }
 432     if (stderr_fd != kInvalidFd) {
 433       internal_close(stderr_fd);
 434     }
 435   });
 436
 437   int pid = internal_fork();
 438
 439   if (pid < 0) {
 440     int rverrno;
 441     if (internal_iserror(pid, &rverrno)) {
 442       Report("WARNING: failed to fork (errno %d)\n", rverrno);
 443     }
 444     return pid;
 445   }
 446
 447   if (pid == 0) {
 448     // Child subprocess
 449     if (stdin_fd != kInvalidFd) {
 450       internal_close(STDIN_FILENO);
 451       internal_dup2(stdin_fd, STDIN_FILENO);
 452       internal_close(stdin_fd);
 453     }
 454     if (stdout_fd != kInvalidFd) {
 455       internal_close(STDOUT_FILENO);
 456       internal_dup2(stdout_fd, STDOUT_FILENO);
 457       internal_close(stdout_fd);
 458     }
 459     if (stderr_fd != kInvalidFd) {
 460       internal_close(STDERR_FILENO);
 461       internal_dup2(stderr_fd, STDERR_FILENO);
 462       internal_close(stderr_fd);
 463     }
 464
 465     for (int fd = sysconf(_SC_OPEN_MAX); fd > 2; fd--) internal_close(fd);
 466
 467     internal_execve(program, const_cast<char **>(&argv[0]),
 468                     const_cast<char *const *>(envp));
 469     internal__exit(1);
 470   }
 471
 472   return pid;
 473 }
 474
 475 bool IsProcessRunning(pid_t pid) {
 476   int process_status;
 477   uptr waitpid_status = internal_waitpid(pid, &process_status, WNOHANG);
 478   int local_errno;
 479   if (internal_iserror(waitpid_status, &local_errno)) {
 480     VReport(1, "Waiting on the process failed (errno %d).\n", local_errno);
 481     return false;
 482   }
 483   return waitpid_status == 0;
 484 }
 485
 486 int WaitForProcess(pid_t pid) {
 487   int process_status;
 488   uptr waitpid_status = internal_waitpid(pid, &process_status, 0);
 489   int local_errno;
 490   if (internal_iserror(waitpid_status, &local_errno)) {
 491     VReport(1, "Waiting on the process failed (errno %d).\n", local_errno);
 492     return -1;
 493   }
 494   return process_status;
 495 }
 496
 497 bool IsStateDetached(int state) {
 498   return state == PTHREAD_CREATE_DETACHED;
 499 }
 500
 501 } // namespace __sanitizer
 502
 503 #endif // SANITIZER_POSIX