libsanitizer/hwasan/hwasan_thread.cpp

   1
   2 #include "hwasan_thread.h"
   3
   4 #include "hwasan.h"
   5 #include "hwasan_interface_internal.h"
   6 #include "hwasan_mapping.h"
   7 #include "hwasan_poisoning.h"
   8 #include "hwasan_thread_list.h"
   9 #include "sanitizer_common/sanitizer_atomic.h"
  10 #include "sanitizer_common/sanitizer_file.h"
  11 #include "sanitizer_common/sanitizer_placement_new.h"
  12 #include "sanitizer_common/sanitizer_tls_get_addr.h"
  13
  14 namespace __hwasan {
  15
  16 static u32 RandomSeed() {
  17   u32 seed;
  18   do {
  19     if (UNLIKELY(!GetRandom(reinterpret_cast<void *>(&seed), sizeof(seed),
  20                             /*blocking=*/false))) {
  21       seed = static_cast<u32>(
  22           (NanoTime() >> 12) ^
  23           (reinterpret_cast<uptr>(__builtin_frame_address(0)) >> 4));
  24     }
  25   } while (!seed);
  26   return seed;
  27 }
  28
  29 void Thread::InitRandomState() {
  30   random_state_ = flags()->random_tags ? RandomSeed() : unique_id_;
  31   random_state_inited_ = true;
  32
  33   // Push a random number of zeros onto the ring buffer so that the first stack
  34   // tag base will be random.
  35   for (tag_t i = 0, e = GenerateRandomTag(); i != e; ++i)
  36     stack_allocations_->push(0);
  37 }
  38
  39 void Thread::Init(uptr stack_buffer_start, uptr stack_buffer_size,
  40                   const InitState *state) {
  41   CHECK_EQ(0, unique_id_);  // try to catch bad stack reuse
  42   CHECK_EQ(0, stack_top_);
  43   CHECK_EQ(0, stack_bottom_);
  44
  45   static atomic_uint64_t unique_id;
  46   unique_id_ = atomic_fetch_add(&unique_id, 1, memory_order_relaxed);
  47   if (!IsMainThread())
  48     os_id_ = GetTid();
  49
  50   if (auto sz = flags()->heap_history_size)
  51     heap_allocations_ = HeapAllocationsRingBuffer::New(sz);
  52
  53 #if !SANITIZER_FUCHSIA
  54   // Do not initialize the stack ring buffer just yet on Fuchsia. Threads will
  55   // be initialized before we enter the thread itself, so we will instead call
  56   // this later.
  57   InitStackRingBuffer(stack_buffer_start, stack_buffer_size);
  58 #endif
  59   InitStackAndTls(state);
  60   dtls_ = DTLS_Get();
  61   AllocatorThreadStart(allocator_cache());
  62
  63   if (flags()->verbose_threads) {
  64     if (IsMainThread()) {
  65       Printf("sizeof(Thread): %zd sizeof(HeapRB): %zd sizeof(StackRB): %zd\n",
  66              sizeof(Thread), heap_allocations_->SizeInBytes(),
  67              stack_allocations_->size() * sizeof(uptr));
  68     }
  69     Print("Creating  : ");
  70   }
  71 }
  72
  73 void Thread::InitStackRingBuffer(uptr stack_buffer_start,
  74                                  uptr stack_buffer_size) {
  75   HwasanTSDThreadInit();  // Only needed with interceptors.
  76   uptr *ThreadLong = GetCurrentThreadLongPtr();
  77   // The following implicitly sets (this) as the current thread.
  78   stack_allocations_ = new (ThreadLong)
  79       StackAllocationsRingBuffer((void *)stack_buffer_start, stack_buffer_size);
  80   // Check that it worked.
  81   CHECK_EQ(GetCurrentThread(), this);
  82
  83   // ScopedTaggingDisable needs GetCurrentThread to be set up.
  84   ScopedTaggingDisabler disabler;
  85
  86   if (stack_bottom_) {
  87     int local;
  88     CHECK(AddrIsInStack((uptr)&local));
  89     CHECK(MemIsApp(stack_bottom_));
  90     CHECK(MemIsApp(stack_top_ - 1));
  91   }
  92 }
  93
  94 void Thread::ClearShadowForThreadStackAndTLS() {
  95   if (stack_top_ != stack_bottom_)
  96     TagMemory(UntagAddr(stack_bottom_),
  97               UntagAddr(stack_top_) - UntagAddr(stack_bottom_),
  98               GetTagFromPointer(stack_top_));
  99   if (tls_begin_ != tls_end_)
 100     TagMemory(UntagAddr(tls_begin_),
 101               UntagAddr(tls_end_) - UntagAddr(tls_begin_),
 102               GetTagFromPointer(tls_begin_));
 103 }
 104
 105 void Thread::Destroy() {
 106   if (flags()->verbose_threads)
 107     Print("Destroying: ");
 108   AllocatorThreadFinish(allocator_cache());
 109   ClearShadowForThreadStackAndTLS();
 110   if (heap_allocations_)
 111     heap_allocations_->Delete();
 112   DTLS_Destroy();
 113   // Unregister this as the current thread.
 114   // Instrumented code can not run on this thread from this point onwards, but
 115   // malloc/free can still be served. Glibc may call free() very late, after all
 116   // TSD destructors are done.
 117   CHECK_EQ(GetCurrentThread(), this);
 118   *GetCurrentThreadLongPtr() = 0;
 119 }
 120
 121 void Thread::Print(const char *Prefix) {
 122   Printf("%sT%zd %p stack: [%p,%p) sz: %zd tls: [%p,%p)\n", Prefix, unique_id_,
 123          (void *)this, stack_bottom(), stack_top(),
 124          stack_top() - stack_bottom(), tls_begin(), tls_end());
 125 }
 126
 127 static u32 xorshift(u32 state) {
 128   state ^= state << 13;
 129   state ^= state >> 17;
 130   state ^= state << 5;
 131   return state;
 132 }
 133
 134 // Generate a (pseudo-)random non-zero tag.
 135 tag_t Thread::GenerateRandomTag(uptr num_bits) {
 136   DCHECK_GT(num_bits, 0);
 137   if (tagging_disabled_)
 138     return 0;
 139   tag_t tag;
 140   const uptr tag_mask = (1ULL << num_bits) - 1;
 141   do {
 142     if (flags()->random_tags) {
 143       if (!random_buffer_) {
 144         EnsureRandomStateInited();
 145         random_buffer_ = random_state_ = xorshift(random_state_);
 146       }
 147       CHECK(random_buffer_);
 148       tag = random_buffer_ & tag_mask;
 149       random_buffer_ >>= num_bits;
 150     } else {
 151       EnsureRandomStateInited();
 152       random_state_ += 1;
 153       tag = random_state_ & tag_mask;
 154     }
 155   } while (!tag);
 156   return tag;
 157 }
 158
 159 void EnsureMainThreadIDIsCorrect() {
 160   auto *t = __hwasan::GetCurrentThread();
 161   if (t && (t->IsMainThread()))
 162     t->set_os_id(GetTid());
 163 }
 164
 165 } // namespace __hwasan
 166
 167 // --- Implementation of LSan-specific functions --- {{{1
 168 namespace __lsan {
 169
 170 static __hwasan::HwasanThreadList *GetHwasanThreadListLocked() {
 171   auto &tl = __hwasan::hwasanThreadList();
 172   tl.CheckLocked();
 173   return &tl;
 174 }
 175
 176 static __hwasan::Thread *GetThreadByOsIDLocked(tid_t os_id) {
 177   return GetHwasanThreadListLocked()->FindThreadLocked(
 178       [os_id](__hwasan::Thread *t) { return t->os_id() == os_id; });
 179 }
 180
 181 void LockThreads() {
 182   __hwasan::hwasanThreadList().Lock();
 183   __hwasan::hwasanThreadArgRetval().Lock();
 184 }
 185
 186 void UnlockThreads() {
 187   __hwasan::hwasanThreadArgRetval().Unlock();
 188   __hwasan::hwasanThreadList().Unlock();
 189 }
 190
 191 void EnsureMainThreadIDIsCorrect() { __hwasan::EnsureMainThreadIDIsCorrect(); }
 192
 193 bool GetThreadRangesLocked(tid_t os_id, uptr *stack_begin, uptr *stack_end,
 194                            uptr *tls_begin, uptr *tls_end, uptr *cache_begin,
 195                            uptr *cache_end, DTLS **dtls) {
 196   auto *t = GetThreadByOsIDLocked(os_id);
 197   if (!t)
 198     return false;
 199   *stack_begin = t->stack_bottom();
 200   *stack_end = t->stack_top();
 201   *tls_begin = t->tls_begin();
 202   *tls_end = t->tls_end();
 203   // Fixme: is this correct for HWASan.
 204   *cache_begin = 0;
 205   *cache_end = 0;
 206   *dtls = t->dtls();
 207   return true;
 208 }
 209
 210 void GetAllThreadAllocatorCachesLocked(InternalMmapVector<uptr> *caches) {}
 211
 212 void GetThreadExtraStackRangesLocked(tid_t os_id,
 213                                      InternalMmapVector<Range> *ranges) {}
 214 void GetThreadExtraStackRangesLocked(InternalMmapVector<Range> *ranges) {}
 215
 216 void GetAdditionalThreadContextPtrsLocked(InternalMmapVector<uptr> *ptrs) {
 217   __hwasan::hwasanThreadArgRetval().GetAllPtrsLocked(ptrs);
 218 }
 219
 220 void GetRunningThreadsLocked(InternalMmapVector<tid_t> *threads) {}
 221
 222 }  // namespace __lsan