1 files changed, 536 insertions, 0 deletions
diff --git a/lib/asan/asan_thread.cpp b/lib/asan/asan_thread.cpp
new file mode 100644
index 000000000000..6734d9a1668c
--- /dev/null
+++ b/lib/asan/asan_thread.cpp
@@ -0,0 +1,536 @@
+//===-- asan_thread.cpp ---------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file is a part of AddressSanitizer, an address sanity checker.
+//
+// Thread-related code.
+//===----------------------------------------------------------------------===//
+#include "asan_allocator.h"
+#include "asan_interceptors.h"
+#include "asan_poisoning.h"
+#include "asan_stack.h"
+#include "asan_thread.h"
+#include "asan_mapping.h"
+#include "sanitizer_common/sanitizer_common.h"
+#include "sanitizer_common/sanitizer_placement_new.h"
+#include "sanitizer_common/sanitizer_stackdepot.h"
+#include "sanitizer_common/sanitizer_tls_get_addr.h"
+#include "lsan/lsan_common.h"
+
+namespace __asan {
+
+// AsanThreadContext implementation.
+
+void AsanThreadContext::OnCreated(void *arg) {
+  CreateThreadContextArgs *args = static_cast<CreateThreadContextArgs*>(arg);
+  if (args->stack)
+    stack_id = StackDepotPut(*args->stack);
+  thread = args->thread;
+  thread->set_context(this);
+}
+
+void AsanThreadContext::OnFinished() {
+  // Drop the link to the AsanThread object.
+  thread = nullptr;
+}
+
+// MIPS requires aligned address
+static ALIGNED(16) char thread_registry_placeholder[sizeof(ThreadRegistry)];
+static ThreadRegistry *asan_thread_registry;
+
+static BlockingMutex mu_for_thread_context(LINKER_INITIALIZED);
+static LowLevelAllocator allocator_for_thread_context;
+
+static ThreadContextBase *GetAsanThreadContext(u32 tid) {
+  BlockingMutexLock lock(&mu_for_thread_context);
+  return new(allocator_for_thread_context) AsanThreadContext(tid);
+}
+
+ThreadRegistry &asanThreadRegistry() {
+  static bool initialized;
+  // Don't worry about thread_safety - this should be called when there is
+  // a single thread.
+  if (!initialized) {
+    // Never reuse ASan threads: we store pointer to AsanThreadContext
+    // in TSD and can't reliably tell when no more TSD destructors will
+    // be called. It would be wrong to reuse AsanThreadContext for another
+    // thread before all TSD destructors will be called for it.
+    asan_thread_registry = new(thread_registry_placeholder) ThreadRegistry(
+        GetAsanThreadContext, kMaxNumberOfThreads, kMaxNumberOfThreads);
+    initialized = true;
+  }
+  return *asan_thread_registry;
+}
+
+AsanThreadContext *GetThreadContextByTidLocked(u32 tid) {
+  return static_cast<AsanThreadContext *>(
+      asanThreadRegistry().GetThreadLocked(tid));
+}
+
+// AsanThread implementation.
+
+AsanThread *AsanThread::Create(thread_callback_t start_routine, void *arg,
+                               u32 parent_tid, StackTrace *stack,
+                               bool detached) {
+  uptr PageSize = GetPageSizeCached();
+  uptr size = RoundUpTo(sizeof(AsanThread), PageSize);
+  AsanThread *thread = (AsanThread*)MmapOrDie(size, __func__);
+  thread->start_routine_ = start_routine;
+  thread->arg_ = arg;
+  AsanThreadContext::CreateThreadContextArgs args = {thread, stack};
+  asanThreadRegistry().CreateThread(*reinterpret_cast<uptr *>(thread), detached,
+                                    parent_tid, &args);
+
+  return thread;
+}
+
+void AsanThread::TSDDtor(void *tsd) {
+  AsanThreadContext *context = (AsanThreadContext*)tsd;
+  VReport(1, "T%d TSDDtor\n", context->tid);
+  if (context->thread)
+    context->thread->Destroy();
+}
+
+void AsanThread::Destroy() {
+  int tid = this->tid();
+  VReport(1, "T%d exited\n", tid);
+
+  malloc_storage().CommitBack();
+  if (common_flags()->use_sigaltstack) UnsetAlternateSignalStack();
+  asanThreadRegistry().FinishThread(tid);
+  FlushToDeadThreadStats(&stats_);
+  // We also clear the shadow on thread destruction because
+  // some code may still be executing in later TSD destructors
+  // and we don't want it to have any poisoned stack.
+  ClearShadowForThreadStackAndTLS();
+  DeleteFakeStack(tid);
+  uptr size = RoundUpTo(sizeof(AsanThread), GetPageSizeCached());
+  UnmapOrDie(this, size);
+  DTLS_Destroy();
+}
+
+void AsanThread::StartSwitchFiber(FakeStack **fake_stack_save, uptr bottom,
+                                  uptr size) {
+  if (atomic_load(&stack_switching_, memory_order_relaxed)) {
+    Report("ERROR: starting fiber switch while in fiber switch\n");
+    Die();
+  }
+
+  next_stack_bottom_ = bottom;
+  next_stack_top_ = bottom + size;
+  atomic_store(&stack_switching_, 1, memory_order_release);
+
+  FakeStack *current_fake_stack = fake_stack_;
+  if (fake_stack_save)
+    *fake_stack_save = fake_stack_;
+  fake_stack_ = nullptr;
+  SetTLSFakeStack(nullptr);
+  // if fake_stack_save is null, the fiber will die, delete the fakestack
+  if (!fake_stack_save && current_fake_stack)
+    current_fake_stack->Destroy(this->tid());
+}
+
+void AsanThread::FinishSwitchFiber(FakeStack *fake_stack_save,
+                                   uptr *bottom_old,
+                                   uptr *size_old) {
+  if (!atomic_load(&stack_switching_, memory_order_relaxed)) {
+    Report("ERROR: finishing a fiber switch that has not started\n");
+    Die();
+  }
+
+  if (fake_stack_save) {
+    SetTLSFakeStack(fake_stack_save);
+    fake_stack_ = fake_stack_save;
+  }
+
+  if (bottom_old)
+    *bottom_old = stack_bottom_;
+  if (size_old)
+    *size_old = stack_top_ - stack_bottom_;
+  stack_bottom_ = next_stack_bottom_;
+  stack_top_ = next_stack_top_;
+  atomic_store(&stack_switching_, 0, memory_order_release);
+  next_stack_top_ = 0;
+  next_stack_bottom_ = 0;
+}
+
+inline AsanThread::StackBounds AsanThread::GetStackBounds() const {
+  if (!atomic_load(&stack_switching_, memory_order_acquire)) {
+    // Make sure the stack bounds are fully initialized.
+    if (stack_bottom_ >= stack_top_) return {0, 0};
+    return {stack_bottom_, stack_top_};
+  }
+  char local;
+  const uptr cur_stack = (uptr)&local;
+  // Note: need to check next stack first, because FinishSwitchFiber
+  // may be in process of overwriting stack_top_/bottom_. But in such case
+  // we are already on the next stack.
+  if (cur_stack >= next_stack_bottom_ && cur_stack < next_stack_top_)
+    return {next_stack_bottom_, next_stack_top_};
+  return {stack_bottom_, stack_top_};
+}
+
+uptr AsanThread::stack_top() {
+  return GetStackBounds().top;
+}
+
+uptr AsanThread::stack_bottom() {
+  return GetStackBounds().bottom;
+}
+
+uptr AsanThread::stack_size() {
+  const auto bounds = GetStackBounds();
+  return bounds.top - bounds.bottom;
+}
+
+// We want to create the FakeStack lazyly on the first use, but not eralier
+// than the stack size is known and the procedure has to be async-signal safe.
+FakeStack *AsanThread::AsyncSignalSafeLazyInitFakeStack() {
+  uptr stack_size = this->stack_size();
+  if (stack_size == 0)  // stack_size is not yet available, don't use FakeStack.
+    return nullptr;
+  uptr old_val = 0;
+  // fake_stack_ has 3 states:
+  // 0   -- not initialized
+  // 1   -- being initialized
+  // ptr -- initialized
+  // This CAS checks if the state was 0 and if so changes it to state 1,
+  // if that was successful, it initializes the pointer.
+  if (atomic_compare_exchange_strong(
+      reinterpret_cast<atomic_uintptr_t *>(&fake_stack_), &old_val, 1UL,
+      memory_order_relaxed)) {
+    uptr stack_size_log = Log2(RoundUpToPowerOfTwo(stack_size));
+    CHECK_LE(flags()->min_uar_stack_size_log, flags()->max_uar_stack_size_log);
+    stack_size_log =
+        Min(stack_size_log, static_cast<uptr>(flags()->max_uar_stack_size_log));
+    stack_size_log =
+        Max(stack_size_log, static_cast<uptr>(flags()->min_uar_stack_size_log));
+    fake_stack_ = FakeStack::Create(stack_size_log);
+    SetTLSFakeStack(fake_stack_);
+    return fake_stack_;
+  }
+  return nullptr;
+}
+
+void AsanThread::Init(const InitOptions *options) {
+  next_stack_top_ = next_stack_bottom_ = 0;
+  atomic_store(&stack_switching_, false, memory_order_release);
+  CHECK_EQ(this->stack_size(), 0U);
+  SetThreadStackAndTls(options);
+  if (stack_top_ != stack_bottom_) {
+    CHECK_GT(this->stack_size(), 0U);
+    CHECK(AddrIsInMem(stack_bottom_));
+    CHECK(AddrIsInMem(stack_top_ - 1));
+  }
+  ClearShadowForThreadStackAndTLS();
+  fake_stack_ = nullptr;
+  if (__asan_option_detect_stack_use_after_return)
+    AsyncSignalSafeLazyInitFakeStack();
+  int local = 0;
+  VReport(1, "T%d: stack [%p,%p) size 0x%zx; local=%p\n", tid(),
+          (void *)stack_bottom_, (void *)stack_top_, stack_top_ - stack_bottom_,
+          &local);
+}
+
+// Fuchsia and RTEMS don't use ThreadStart.
+// asan_fuchsia.c/asan_rtems.c define CreateMainThread and
+// SetThreadStackAndTls.
+#if !SANITIZER_FUCHSIA && !SANITIZER_RTEMS
+
+thread_return_t AsanThread::ThreadStart(
+    tid_t os_id, atomic_uintptr_t *signal_thread_is_registered) {
+  Init();
+  asanThreadRegistry().StartThread(tid(), os_id, ThreadType::Regular, nullptr);
+  if (signal_thread_is_registered)
+    atomic_store(signal_thread_is_registered, 1, memory_order_release);
+
+  if (common_flags()->use_sigaltstack) SetAlternateSignalStack();
+
+  if (!start_routine_) {
+    // start_routine_ == 0 if we're on the main thread or on one of the
+    // OS X libdispatch worker threads. But nobody is supposed to call
+    // ThreadStart() for the worker threads.
+    CHECK_EQ(tid(), 0);
+    return 0;
+  }
+
+  thread_return_t res = start_routine_(arg_);
+
+  // On POSIX systems we defer this to the TSD destructor. LSan will consider
+  // the thread's memory as non-live from the moment we call Destroy(), even
+  // though that memory might contain pointers to heap objects which will be
+  // cleaned up by a user-defined TSD destructor. Thus, calling Destroy() before
+  // the TSD destructors have run might cause false positives in LSan.
+  if (!SANITIZER_POSIX)
+    this->Destroy();
+
+  return res;
+}
+
+AsanThread *CreateMainThread() {
+  AsanThread *main_thread = AsanThread::Create(
+      /* start_routine */ nullptr, /* arg */ nullptr, /* parent_tid */ 0,
+      /* stack */ nullptr, /* detached */ true);
+  SetCurrentThread(main_thread);
+  main_thread->ThreadStart(internal_getpid(),
+                           /* signal_thread_is_registered */ nullptr);
+  return main_thread;
+}
+
+// This implementation doesn't use the argument, which is just passed down
+// from the caller of Init (which see, above).  It's only there to support
+// OS-specific implementations that need more information passed through.
+void AsanThread::SetThreadStackAndTls(const InitOptions *options) {
+  DCHECK_EQ(options, nullptr);
+  uptr tls_size = 0;
+  uptr stack_size = 0;
+  GetThreadStackAndTls(tid() == 0, &stack_bottom_, &stack_size, &tls_begin_,
+                       &tls_size);
+  stack_top_ = stack_bottom_ + stack_size;
+  tls_end_ = tls_begin_ + tls_size;
+  dtls_ = DTLS_Get();
+
+  if (stack_top_ != stack_bottom_) {
+    int local;
+    CHECK(AddrIsInStack((uptr)&local));
+  }
+}
+
+#endif  // !SANITIZER_FUCHSIA && !SANITIZER_RTEMS
+
+void AsanThread::ClearShadowForThreadStackAndTLS() {
+  if (stack_top_ != stack_bottom_)
+    PoisonShadow(stack_bottom_, stack_top_ - stack_bottom_, 0);
+  if (tls_begin_ != tls_end_) {
+    uptr tls_begin_aligned = RoundDownTo(tls_begin_, SHADOW_GRANULARITY);
+    uptr tls_end_aligned = RoundUpTo(tls_end_, SHADOW_GRANULARITY);
+    FastPoisonShadowPartialRightRedzone(tls_begin_aligned,
+                                        tls_end_ - tls_begin_aligned,
+                                        tls_end_aligned - tls_end_, 0);
+  }
+}
+
+bool AsanThread::GetStackFrameAccessByAddr(uptr addr,
+                                           StackFrameAccess *access) {
+  if (stack_top_ == stack_bottom_)
+    return false;
+
+  uptr bottom = 0;
+  if (AddrIsInStack(addr)) {
+    bottom = stack_bottom();
+  } else if (has_fake_stack()) {
+    bottom = fake_stack()->AddrIsInFakeStack(addr);
+    CHECK(bottom);
+    access->offset = addr - bottom;
+    access->frame_pc = ((uptr*)bottom)[2];
+    access->frame_descr = (const char *)((uptr*)bottom)[1];
+    return true;
+  }
+  uptr aligned_addr = RoundDownTo(addr, SANITIZER_WORDSIZE / 8);  // align addr.
+  uptr mem_ptr = RoundDownTo(aligned_addr, SHADOW_GRANULARITY);
+  u8 *shadow_ptr = (u8*)MemToShadow(aligned_addr);
+  u8 *shadow_bottom = (u8*)MemToShadow(bottom);
+
+  while (shadow_ptr >= shadow_bottom &&
+         *shadow_ptr != kAsanStackLeftRedzoneMagic) {
+    shadow_ptr--;
+    mem_ptr -= SHADOW_GRANULARITY;
+  }
+
+  while (shadow_ptr >= shadow_bottom &&
+         *shadow_ptr == kAsanStackLeftRedzoneMagic) {
+    shadow_ptr--;
+    mem_ptr -= SHADOW_GRANULARITY;
+  }
+
+  if (shadow_ptr < shadow_bottom) {
+    return false;
+  }
+
+  uptr* ptr = (uptr*)(mem_ptr + SHADOW_GRANULARITY);
+  CHECK(ptr[0] == kCurrentStackFrameMagic);
+  access->offset = addr - (uptr)ptr;
+  access->frame_pc = ptr[2];
+  access->frame_descr = (const char*)ptr[1];
+  return true;
+}
+
+uptr AsanThread::GetStackVariableShadowStart(uptr addr) {
+  uptr bottom = 0;
+  if (AddrIsInStack(addr)) {
+    bottom = stack_bottom();
+  } else if (has_fake_stack()) {
+    bottom = fake_stack()->AddrIsInFakeStack(addr);
+    CHECK(bottom);
+  } else {
+    return 0;
+  }
+
+  uptr aligned_addr = RoundDownTo(addr, SANITIZER_WORDSIZE / 8);  // align addr.
+  u8 *shadow_ptr = (u8*)MemToShadow(aligned_addr);
+  u8 *shadow_bottom = (u8*)MemToShadow(bottom);
+
+  while (shadow_ptr >= shadow_bottom &&
+         (*shadow_ptr != kAsanStackLeftRedzoneMagic &&
+          *shadow_ptr != kAsanStackMidRedzoneMagic &&
+          *shadow_ptr != kAsanStackRightRedzoneMagic))
+    shadow_ptr--;
+
+  return (uptr)shadow_ptr + 1;
+}
+
+bool AsanThread::AddrIsInStack(uptr addr) {
+  const auto bounds = GetStackBounds();
+  return addr >= bounds.bottom && addr < bounds.top;
+}
+
+static bool ThreadStackContainsAddress(ThreadContextBase *tctx_base,
+                                       void *addr) {
+  AsanThreadContext *tctx = static_cast<AsanThreadContext*>(tctx_base);
+  AsanThread *t = tctx->thread;
+  if (!t) return false;
+  if (t->AddrIsInStack((uptr)addr)) return true;
+  if (t->has_fake_stack() && t->fake_stack()->AddrIsInFakeStack((uptr)addr))
+    return true;
+  return false;
+}
+
+AsanThread *GetCurrentThread() {
+  if (SANITIZER_RTEMS && !asan_inited)
+    return nullptr;
+
+  AsanThreadContext *context =
+      reinterpret_cast<AsanThreadContext *>(AsanTSDGet());
+  if (!context) {
+    if (SANITIZER_ANDROID) {
+      // On Android, libc constructor is called _after_ asan_init, and cleans up
+      // TSD. Try to figure out if this is still the main thread by the stack
+      // address. We are not entirely sure that we have correct main thread
+      // limits, so only do this magic on Android, and only if the found thread
+      // is the main thread.
+      AsanThreadContext *tctx = GetThreadContextByTidLocked(0);
+      if (tctx && ThreadStackContainsAddress(tctx, &context)) {
+        SetCurrentThread(tctx->thread);
+        return tctx->thread;
+      }
+    }
+    return nullptr;
+  }
+  return context->thread;
+}
+
+void SetCurrentThread(AsanThread *t) {
+  CHECK(t->context());
+  VReport(2, "SetCurrentThread: %p for thread %p\n", t->context(),
+          (void *)GetThreadSelf());
+  // Make sure we do not reset the current AsanThread.
+  CHECK_EQ(0, AsanTSDGet());
+  AsanTSDSet(t->context());
+  CHECK_EQ(t->context(), AsanTSDGet());
+}
+
+u32 GetCurrentTidOrInvalid() {
+  AsanThread *t = GetCurrentThread();
+  return t ? t->tid() : kInvalidTid;
+}
+
+AsanThread *FindThreadByStackAddress(uptr addr) {
+  asanThreadRegistry().CheckLocked();
+  AsanThreadContext *tctx = static_cast<AsanThreadContext *>(
+      asanThreadRegistry().FindThreadContextLocked(ThreadStackContainsAddress,
+                                                   (void *)addr));
+  return tctx ? tctx->thread : nullptr;
+}
+
+void EnsureMainThreadIDIsCorrect() {
+  AsanThreadContext *context =
+      reinterpret_cast<AsanThreadContext *>(AsanTSDGet());
+  if (context && (context->tid == 0))
+    context->os_id = GetTid();
+}
+
+__asan::AsanThread *GetAsanThreadByOsIDLocked(tid_t os_id) {
+  __asan::AsanThreadContext *context = static_cast<__asan::AsanThreadContext *>(
+      __asan::asanThreadRegistry().FindThreadContextByOsIDLocked(os_id));
+  if (!context) return nullptr;
+  return context->thread;
+}
+} // namespace __asan
+
+// --- Implementation of LSan-specific functions --- {{{1
+namespace __lsan {
+bool GetThreadRangesLocked(tid_t os_id, uptr *stack_begin, uptr *stack_end,
+                           uptr *tls_begin, uptr *tls_end, uptr *cache_begin,
+                           uptr *cache_end, DTLS **dtls) {
+  __asan::AsanThread *t = __asan::GetAsanThreadByOsIDLocked(os_id);
+  if (!t) return false;
+  *stack_begin = t->stack_bottom();
+  *stack_end = t->stack_top();
+  *tls_begin = t->tls_begin();
+  *tls_end = t->tls_end();
+  // ASan doesn't keep allocator caches in TLS, so these are unused.
+  *cache_begin = 0;
+  *cache_end = 0;
+  *dtls = t->dtls();
+  return true;
+}
+
+void ForEachExtraStackRange(tid_t os_id, RangeIteratorCallback callback,
+                            void *arg) {
+  __asan::AsanThread *t = __asan::GetAsanThreadByOsIDLocked(os_id);
+  if (t && t->has_fake_stack())
+    t->fake_stack()->ForEachFakeFrame(callback, arg);
+}
+
+void LockThreadRegistry() {
+  __asan::asanThreadRegistry().Lock();
+}
+
+void UnlockThreadRegistry() {
+  __asan::asanThreadRegistry().Unlock();
+}
+
+ThreadRegistry *GetThreadRegistryLocked() {
+  __asan::asanThreadRegistry().CheckLocked();
+  return &__asan::asanThreadRegistry();
+}
+
+void EnsureMainThreadIDIsCorrect() {
+  __asan::EnsureMainThreadIDIsCorrect();
+}
+} // namespace __lsan
+
+// ---------------------- Interface ---------------- {{{1
+using namespace __asan;
+
+extern "C" {
+SANITIZER_INTERFACE_ATTRIBUTE
+void __sanitizer_start_switch_fiber(void **fakestacksave, const void *bottom,
+                                    uptr size) {
+  AsanThread *t = GetCurrentThread();
+  if (!t) {
+    VReport(1, "__asan_start_switch_fiber called from unknown thread\n");
+    return;
+  }
+  t->StartSwitchFiber((FakeStack**)fakestacksave, (uptr)bottom, size);
+}
+
+SANITIZER_INTERFACE_ATTRIBUTE
+void __sanitizer_finish_switch_fiber(void* fakestack,
+                                     const void **bottom_old,
+                                     uptr *size_old) {
+  AsanThread *t = GetCurrentThread();
+  if (!t) {
+    VReport(1, "__asan_finish_switch_fiber called from unknown thread\n");
+    return;
+  }
+  t->FinishSwitchFiber((FakeStack*)fakestack,
+                       (uptr*)bottom_old,
+                       (uptr*)size_old);
+}
+}