1 #include "dfsan_thread.h" 2 3 #include <pthread.h> 4 5 #include "dfsan.h" 6 #include "sanitizer_common/sanitizer_tls_get_addr.h" 7 8 namespace __dfsan { 9 10 DFsanThread *DFsanThread::Create(thread_callback_t start_routine, void *arg, 11 bool track_origins) { 12 uptr PageSize = GetPageSizeCached(); 13 uptr size = RoundUpTo(sizeof(DFsanThread), PageSize); 14 DFsanThread *thread = (DFsanThread *)MmapOrDie(size, __func__); 15 thread->start_routine_ = start_routine; 16 thread->arg_ = arg; 17 thread->track_origins_ = track_origins; 18 thread->destructor_iterations_ = GetPthreadDestructorIterations(); 19 20 return thread; 21 } 22 23 void DFsanThread::SetThreadStackAndTls() { 24 uptr tls_size = 0; 25 uptr stack_size = 0; 26 GetThreadStackAndTls(IsMainThread(), &stack_.bottom, &stack_size, &tls_begin_, 27 &tls_size); 28 stack_.top = stack_.bottom + stack_size; 29 tls_end_ = tls_begin_ + tls_size; 30 31 int local; 32 CHECK(AddrIsInStack((uptr)&local)); 33 } 34 35 void DFsanThread::ClearShadowForThreadStackAndTLS() { 36 dfsan_set_label(0, (void *)stack_.bottom, stack_.top - stack_.bottom); 37 if (tls_begin_ != tls_end_) 38 dfsan_set_label(0, (void *)tls_begin_, tls_end_ - tls_begin_); 39 DTLS *dtls = DTLS_Get(); 40 CHECK_NE(dtls, 0); 41 ForEachDVT(dtls, [](const DTLS::DTV &dtv, int id) { 42 dfsan_set_label(0, (void *)(dtv.beg), dtv.size); 43 }); 44 } 45 46 void DFsanThread::Init() { 47 SetThreadStackAndTls(); 48 ClearShadowForThreadStackAndTLS(); 49 } 50 51 void DFsanThread::TSDDtor(void *tsd) { 52 DFsanThread *t = (DFsanThread *)tsd; 53 t->Destroy(); 54 } 55 56 void DFsanThread::Destroy() { 57 malloc_storage().CommitBack(); 58 // We also clear the shadow on thread destruction because 59 // some code may still be executing in later TSD destructors 60 // and we don't want it to have any poisoned stack. 61 ClearShadowForThreadStackAndTLS(); 62 uptr size = RoundUpTo(sizeof(DFsanThread), GetPageSizeCached()); 63 UnmapOrDie(this, size); 64 DTLS_Destroy(); 65 } 66 67 thread_return_t DFsanThread::ThreadStart() { 68 if (!start_routine_) { 69 // start_routine_ == 0 if we're on the main thread or on one of the 70 // OS X libdispatch worker threads. But nobody is supposed to call 71 // ThreadStart() for the worker threads. 72 return 0; 73 } 74 75 // The only argument is void* arg. 76 // 77 // We have never supported propagating the pointer arg as tainted, 78 // __dfsw_pthread_create/__dfso_pthread_create ignore the taint label. 79 // Note that the bytes pointed-to (probably the much more common case) 80 // can still have taint labels attached to them. 81 dfsan_clear_thread_local_state(); 82 83 return start_routine_(arg_); 84 } 85 86 DFsanThread::StackBounds DFsanThread::GetStackBounds() const { 87 return {stack_.bottom, stack_.top}; 88 } 89 90 uptr DFsanThread::stack_top() { return GetStackBounds().top; } 91 92 uptr DFsanThread::stack_bottom() { return GetStackBounds().bottom; } 93 94 bool DFsanThread::AddrIsInStack(uptr addr) { 95 const auto bounds = GetStackBounds(); 96 return addr >= bounds.bottom && addr < bounds.top; 97 } 98 99 static pthread_key_t tsd_key; 100 static bool tsd_key_inited = false; 101 102 void DFsanTSDInit(void (*destructor)(void *tsd)) { 103 CHECK(!tsd_key_inited); 104 tsd_key_inited = true; 105 CHECK_EQ(0, pthread_key_create(&tsd_key, destructor)); 106 } 107 108 static THREADLOCAL DFsanThread *dfsan_current_thread; 109 110 DFsanThread *GetCurrentThread() { return dfsan_current_thread; } 111 112 void SetCurrentThread(DFsanThread *t) { 113 // Make sure we do not reset the current DFsanThread. 114 CHECK_EQ(0, dfsan_current_thread); 115 dfsan_current_thread = t; 116 // Make sure that DFsanTSDDtor gets called at the end. 117 CHECK(tsd_key_inited); 118 pthread_setspecific(tsd_key, t); 119 } 120 121 void DFsanTSDDtor(void *tsd) { 122 DFsanThread *t = (DFsanThread *)tsd; 123 if (t->destructor_iterations_ > 1) { 124 t->destructor_iterations_--; 125 CHECK_EQ(0, pthread_setspecific(tsd_key, tsd)); 126 return; 127 } 128 dfsan_current_thread = nullptr; 129 // Make sure that signal handler can not see a stale current thread pointer. 130 atomic_signal_fence(memory_order_seq_cst); 131 DFsanThread::TSDDtor(tsd); 132 } 133 134 } // namespace __dfsan 135