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