libsanitizer/asan/asan_posix.cpp

   1 //===-- asan_posix.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 a part of AddressSanitizer, an address sanity checker.
  10 //
  11 // Posix-specific details.
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "sanitizer_common/sanitizer_platform.h"
  15 #if SANITIZER_POSIX
  16
  17 #include "asan_internal.h"
  18 #include "asan_interceptors.h"
  19 #include "asan_mapping.h"
  20 #include "asan_poisoning.h"
  21 #include "asan_report.h"
  22 #include "asan_stack.h"
  23 #include "sanitizer_common/sanitizer_libc.h"
  24 #include "sanitizer_common/sanitizer_posix.h"
  25 #include "sanitizer_common/sanitizer_procmaps.h"
  26
  27 #include <pthread.h>
  28 #include <signal.h>
  29 #include <stdlib.h>
  30 #include <sys/time.h>
  31 #include <sys/resource.h>
  32 #include <unistd.h>
  33
  34 namespace __asan {
  35
  36 void AsanOnDeadlySignal(int signo, void *siginfo, void *context) {
  37   StartReportDeadlySignal();
  38   SignalContext sig(siginfo, context);
  39   ReportDeadlySignal(sig);
  40 }
  41
  42 bool PlatformUnpoisonStacks() {
  43   stack_t signal_stack;
  44   CHECK_EQ(0, sigaltstack(nullptr, &signal_stack));
  45   uptr sigalt_bottom = (uptr)signal_stack.ss_sp;
  46   uptr sigalt_top = (uptr)((char *)signal_stack.ss_sp + signal_stack.ss_size);
  47   // If we're executing on the signal alternate stack AND the Linux flag
  48   // SS_AUTODISARM was used, then we cannot get the signal alternate stack
  49   // bounds from sigaltstack -- sigaltstack's output looks just as if no
  50   // alternate stack has ever been set up.
  51   // We're always unpoisoning the signal alternate stack to support jumping
  52   // between the default stack and signal alternate stack.
  53   if (signal_stack.ss_flags != SS_DISABLE)
  54     UnpoisonStack(sigalt_bottom, sigalt_top, "sigalt");
  55
  56   if (signal_stack.ss_flags != SS_ONSTACK)
  57     return false;
  58
  59   // Since we're on the signal alternate stack, we cannot find the DEFAULT
  60   // stack bottom using a local variable.
  61   uptr default_bottom, tls_addr, tls_size, stack_size;
  62   GetThreadStackAndTls(/*main=*/false, &default_bottom, &stack_size, &tls_addr,
  63                        &tls_size);
  64   UnpoisonStack(default_bottom, default_bottom + stack_size, "default");
  65   return true;
  66 }
  67
  68 // ---------------------- TSD ---------------- {{{1
  69
  70 #if SANITIZER_NETBSD && !ASAN_DYNAMIC
  71 // Thread Static Data cannot be used in early static ASan init on NetBSD.
  72 // Reuse the Asan TSD API for compatibility with existing code
  73 // with an alternative implementation.
  74
  75 static void (*tsd_destructor)(void *tsd) = nullptr;
  76
  77 struct tsd_key {
  78   tsd_key() : key(nullptr) {}
  79   ~tsd_key() {
  80     CHECK(tsd_destructor);
  81     if (key)
  82       (*tsd_destructor)(key);
  83   }
  84   void *key;
  85 };
  86
  87 static thread_local struct tsd_key key;
  88
  89 void AsanTSDInit(void (*destructor)(void *tsd)) {
  90   CHECK(!tsd_destructor);
  91   tsd_destructor = destructor;
  92 }
  93
  94 void *AsanTSDGet() {
  95   CHECK(tsd_destructor);
  96   return key.key;
  97 }
  98
  99 void AsanTSDSet(void *tsd) {
 100   CHECK(tsd_destructor);
 101   CHECK(tsd);
 102   CHECK(!key.key);
 103   key.key = tsd;
 104 }
 105
 106 void PlatformTSDDtor(void *tsd) {
 107   CHECK(tsd_destructor);
 108   CHECK_EQ(key.key, tsd);
 109   key.key = nullptr;
 110   // Make sure that signal handler can not see a stale current thread pointer.
 111   atomic_signal_fence(memory_order_seq_cst);
 112   AsanThread::TSDDtor(tsd);
 113 }
 114 #else
 115 static pthread_key_t tsd_key;
 116 static bool tsd_key_inited = false;
 117 void AsanTSDInit(void (*destructor)(void *tsd)) {
 118   CHECK(!tsd_key_inited);
 119   tsd_key_inited = true;
 120   CHECK_EQ(0, pthread_key_create(&tsd_key, destructor));
 121 }
 122
 123 void *AsanTSDGet() {
 124   CHECK(tsd_key_inited);
 125   return pthread_getspecific(tsd_key);
 126 }
 127
 128 void AsanTSDSet(void *tsd) {
 129   CHECK(tsd_key_inited);
 130   pthread_setspecific(tsd_key, tsd);
 131 }
 132
 133 void PlatformTSDDtor(void *tsd) {
 134   AsanThreadContext *context = (AsanThreadContext*)tsd;
 135   if (context->destructor_iterations > 1) {
 136     context->destructor_iterations--;
 137     CHECK_EQ(0, pthread_setspecific(tsd_key, tsd));
 138     return;
 139   }
 140   AsanThread::TSDDtor(tsd);
 141 }
 142 #endif
 143 }  // namespace __asan
 144
 145 #endif  // SANITIZER_POSIX