libsanitizer/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_openbsd.h"
  22 #include "sanitizer_platform_limits_posix.h"
  23 #include "sanitizer_platform_limits_solaris.h"
  24 #include "sanitizer_posix.h"
  25 #include "sanitizer_procmaps.h"
  26
  27 #include <errno.h>
  28 #include <fcntl.h>
  29 #include <pthread.h>
  30 #include <signal.h>
  31 #include <stdlib.h>
  32 #include <sys/mman.h>
  33 #include <sys/resource.h>
  34 #include <sys/stat.h>
  35 #include <sys/time.h>
  36 #include <sys/types.h>
  37 #include <sys/wait.h>
  38 #include <unistd.h>
  39
  40 #if SANITIZER_FREEBSD
  41 // The MAP_NORESERVE define has been removed in FreeBSD 11.x, and even before
  42 // that, it was never implemented.  So just define it to zero.
  43 #undef MAP_NORESERVE
  44 #define MAP_NORESERVE 0
  45 #endif
  46
  47 typedef void (*sa_sigaction_t)(int, siginfo_t *, void *);
  48
  49 namespace __sanitizer {
  50
  51 u32 GetUid() {
  52   return getuid();
  53 }
  54
  55 uptr GetThreadSelf() {
  56   return (uptr)pthread_self();
  57 }
  58
  59 void ReleaseMemoryPagesToOS(uptr beg, uptr end) {
  60   uptr page_size = GetPageSizeCached();
  61   uptr beg_aligned = RoundUpTo(beg, page_size);
  62   uptr end_aligned = RoundDownTo(end, page_size);
  63   if (beg_aligned < end_aligned)
  64     // In the default Solaris compilation environment, madvise() is declared
  65     // to take a caddr_t arg; casting it to void * results in an invalid
  66     // conversion error, so use char * instead.
  67     madvise((char *)beg_aligned, end_aligned - beg_aligned,
  68             SANITIZER_MADVISE_DONTNEED);
  69 }
  70
  71 void SetShadowRegionHugePageMode(uptr addr, uptr size) {
  72 #ifdef MADV_NOHUGEPAGE  // May not be defined on old systems.
  73   if (common_flags()->no_huge_pages_for_shadow)
  74     madvise((char *)addr, size, MADV_NOHUGEPAGE);
  75   else
  76     madvise((char *)addr, size, MADV_HUGEPAGE);
  77 #endif  // MADV_NOHUGEPAGE
  78 }
  79
  80 bool DontDumpShadowMemory(uptr addr, uptr length) {
  81 #if defined(MADV_DONTDUMP)
  82   return madvise((char *)addr, length, MADV_DONTDUMP) == 0;
  83 #elif defined(MADV_NOCORE)
  84   return madvise((char *)addr, length, MADV_NOCORE) == 0;
  85 #else
  86   return true;
  87 #endif  // MADV_DONTDUMP
  88 }
  89
  90 static rlim_t getlim(int res) {
  91   rlimit rlim;
  92   CHECK_EQ(0, getrlimit(res, &rlim));
  93   return rlim.rlim_cur;
  94 }
  95
  96 static void setlim(int res, rlim_t lim) {
  97   struct rlimit rlim;
  98   if (getrlimit(res, const_cast<struct rlimit *>(&rlim))) {
  99     Report("ERROR: %s getrlimit() failed %d\n", SanitizerToolName, errno);
 100     Die();
 101   }
 102   rlim.rlim_cur = lim;
 103   if (setrlimit(res, const_cast<struct rlimit *>(&rlim))) {
 104     Report("ERROR: %s setrlimit() failed %d\n", SanitizerToolName, errno);
 105     Die();
 106   }
 107 }
 108
 109 void DisableCoreDumperIfNecessary() {
 110   if (common_flags()->disable_coredump) {
 111     setlim(RLIMIT_CORE, 0);
 112   }
 113 }
 114
 115 bool StackSizeIsUnlimited() {
 116   rlim_t stack_size = getlim(RLIMIT_STACK);
 117   return (stack_size == RLIM_INFINITY);
 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 static bool MmapFixed(uptr fixed_addr, uptr size, int additional_flags,
 308                       const char *name) {
 309   size = RoundUpTo(size, GetPageSizeCached());
 310   fixed_addr = RoundDownTo(fixed_addr, GetPageSizeCached());
 311   uptr p =
 312       MmapNamed((void *)fixed_addr, size, PROT_READ | PROT_WRITE,
 313                 MAP_PRIVATE | MAP_FIXED | additional_flags | MAP_ANON, name);
 314   int reserrno;
 315   if (internal_iserror(p, &reserrno)) {
 316     Report("ERROR: %s failed to "
 317            "allocate 0x%zx (%zd) bytes at address %zx (errno: %d)\n",
 318            SanitizerToolName, size, size, fixed_addr, reserrno);
 319     return false;
 320   }
 321   IncreaseTotalMmap(size);
 322   return true;
 323 }
 324
 325 bool MmapFixedNoReserve(uptr fixed_addr, uptr size, const char *name) {
 326   return MmapFixed(fixed_addr, size, MAP_NORESERVE, name);
 327 }
 328
 329 bool MmapFixedSuperNoReserve(uptr fixed_addr, uptr size, const char *name) {
 330 #if SANITIZER_FREEBSD
 331   if (common_flags()->no_huge_pages_for_shadow)
 332     return MmapFixedNoReserve(fixed_addr, size, name);
 333   // MAP_NORESERVE is implicit with FreeBSD
 334   return MmapFixed(fixed_addr, size, MAP_ALIGNED_SUPER, name);
 335 #else
 336   bool r = MmapFixedNoReserve(fixed_addr, size, name);
 337   if (r)
 338     SetShadowRegionHugePageMode(fixed_addr, size);
 339   return r;
 340 #endif
 341 }
 342
 343 uptr ReservedAddressRange::Init(uptr size, const char *name, uptr fixed_addr) {
 344   base_ = fixed_addr ? MmapFixedNoAccess(fixed_addr, size, name)
 345                      : MmapNoAccess(size);
 346   size_ = size;
 347   name_ = name;
 348   (void)os_handle_;  // unsupported
 349   return reinterpret_cast<uptr>(base_);
 350 }
 351
 352 // Uses fixed_addr for now.
 353 // Will use offset instead once we've implemented this function for real.
 354 uptr ReservedAddressRange::Map(uptr fixed_addr, uptr size, const char *name) {
 355   return reinterpret_cast<uptr>(
 356       MmapFixedOrDieOnFatalError(fixed_addr, size, name));
 357 }
 358
 359 uptr ReservedAddressRange::MapOrDie(uptr fixed_addr, uptr size,
 360                                     const char *name) {
 361   return reinterpret_cast<uptr>(MmapFixedOrDie(fixed_addr, size, name));
 362 }
 363
 364 void ReservedAddressRange::Unmap(uptr addr, uptr size) {
 365   CHECK_LE(size, size_);
 366   if (addr == reinterpret_cast<uptr>(base_))
 367     // If we unmap the whole range, just null out the base.
 368     base_ = (size == size_) ? nullptr : reinterpret_cast<void*>(addr + size);
 369   else
 370     CHECK_EQ(addr + size, reinterpret_cast<uptr>(base_) + size_);
 371   size_ -= size;
 372   UnmapOrDie(reinterpret_cast<void*>(addr), size);
 373 }
 374
 375 void *MmapFixedNoAccess(uptr fixed_addr, uptr size, const char *name) {
 376   return (void *)MmapNamed((void *)fixed_addr, size, PROT_NONE,
 377                            MAP_PRIVATE | MAP_FIXED | MAP_NORESERVE | MAP_ANON,
 378                            name);
 379 }
 380
 381 void *MmapNoAccess(uptr size) {
 382   unsigned flags = MAP_PRIVATE | MAP_ANON | MAP_NORESERVE;
 383   return (void *)internal_mmap(nullptr, size, PROT_NONE, flags, -1, 0);
 384 }
 385
 386 // This function is defined elsewhere if we intercepted pthread_attr_getstack.
 387 extern "C" {
 388 SANITIZER_WEAK_ATTRIBUTE int
 389 real_pthread_attr_getstack(void *attr, void **addr, size_t *size);
 390 } // extern "C"
 391
 392 int my_pthread_attr_getstack(void *attr, void **addr, uptr *size) {
 393 #if !SANITIZER_GO && !SANITIZER_MAC
 394   if (&real_pthread_attr_getstack)
 395     return real_pthread_attr_getstack((pthread_attr_t *)attr, addr,
 396                                       (size_t *)size);
 397 #endif
 398   return pthread_attr_getstack((pthread_attr_t *)attr, addr, (size_t *)size);
 399 }
 400
 401 #if !SANITIZER_GO
 402 void AdjustStackSize(void *attr_) {
 403   pthread_attr_t *attr = (pthread_attr_t *)attr_;
 404   uptr stackaddr = 0;
 405   uptr stacksize = 0;
 406   my_pthread_attr_getstack(attr, (void**)&stackaddr, &stacksize);
 407   // GLibC will return (0 - stacksize) as the stack address in the case when
 408   // stacksize is set, but stackaddr is not.
 409   bool stack_set = (stackaddr != 0) && (stackaddr + stacksize != 0);
 410   // We place a lot of tool data into TLS, account for that.
 411   const uptr minstacksize = GetTlsSize() + 128*1024;
 412   if (stacksize < minstacksize) {
 413     if (!stack_set) {
 414       if (stacksize != 0) {
 415         VPrintf(1, "Sanitizer: increasing stacksize %zu->%zu\n", stacksize,
 416                 minstacksize);
 417         pthread_attr_setstacksize(attr, minstacksize);
 418       }
 419     } else {
 420       Printf("Sanitizer: pre-allocated stack size is insufficient: "
 421              "%zu < %zu\n", stacksize, minstacksize);
 422       Printf("Sanitizer: pthread_create is likely to fail.\n");
 423     }
 424   }
 425 }
 426 #endif // !SANITIZER_GO
 427
 428 pid_t StartSubprocess(const char *program, const char *const argv[],
 429                       fd_t stdin_fd, fd_t stdout_fd, fd_t stderr_fd) {
 430   auto file_closer = at_scope_exit([&] {
 431     if (stdin_fd != kInvalidFd) {
 432       internal_close(stdin_fd);
 433     }
 434     if (stdout_fd != kInvalidFd) {
 435       internal_close(stdout_fd);
 436     }
 437     if (stderr_fd != kInvalidFd) {
 438       internal_close(stderr_fd);
 439     }
 440   });
 441
 442   int pid = internal_fork();
 443
 444   if (pid < 0) {
 445     int rverrno;
 446     if (internal_iserror(pid, &rverrno)) {
 447       Report("WARNING: failed to fork (errno %d)\n", rverrno);
 448     }
 449     return pid;
 450   }
 451
 452   if (pid == 0) {
 453     // Child subprocess
 454     if (stdin_fd != kInvalidFd) {
 455       internal_close(STDIN_FILENO);
 456       internal_dup2(stdin_fd, STDIN_FILENO);
 457       internal_close(stdin_fd);
 458     }
 459     if (stdout_fd != kInvalidFd) {
 460       internal_close(STDOUT_FILENO);
 461       internal_dup2(stdout_fd, STDOUT_FILENO);
 462       internal_close(stdout_fd);
 463     }
 464     if (stderr_fd != kInvalidFd) {
 465       internal_close(STDERR_FILENO);
 466       internal_dup2(stderr_fd, STDERR_FILENO);
 467       internal_close(stderr_fd);
 468     }
 469
 470     for (int fd = sysconf(_SC_OPEN_MAX); fd > 2; fd--) internal_close(fd);
 471
 472     execv(program, const_cast<char **>(&argv[0]));
 473     internal__exit(1);
 474   }
 475
 476   return pid;
 477 }
 478
 479 bool IsProcessRunning(pid_t pid) {
 480   int process_status;
 481   uptr waitpid_status = internal_waitpid(pid, &process_status, WNOHANG);
 482   int local_errno;
 483   if (internal_iserror(waitpid_status, &local_errno)) {
 484     VReport(1, "Waiting on the process failed (errno %d).\n", local_errno);
 485     return false;
 486   }
 487   return waitpid_status == 0;
 488 }
 489
 490 int WaitForProcess(pid_t pid) {
 491   int process_status;
 492   uptr waitpid_status = internal_waitpid(pid, &process_status, 0);
 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 -1;
 497   }
 498   return process_status;
 499 }
 500
 501 bool IsStateDetached(int state) {
 502   return state == PTHREAD_CREATE_DETACHED;
 503 }
 504
 505 } // namespace __sanitizer
 506
 507 #endif // SANITIZER_POSIX