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#include "hwasan_thread.h"
#include "hwasan.h"
#include "hwasan_interface_internal.h"
#include "hwasan_mapping.h"
#include "hwasan_poisoning.h"
#include "sanitizer_common/sanitizer_atomic.h"
#include "sanitizer_common/sanitizer_file.h"
#include "sanitizer_common/sanitizer_placement_new.h"
#include "sanitizer_common/sanitizer_tls_get_addr.h"
namespace __hwasan {
static u32 RandomSeed() {
u32 seed;
do {
if (UNLIKELY(!GetRandom(reinterpret_cast<void *>(&seed), sizeof(seed),
/*blocking=*/false))) {
seed = static_cast<u32>(
(NanoTime() >> 12) ^
(reinterpret_cast<uptr>(__builtin_frame_address(0)) >> 4));
}
} while (!seed);
return seed;
}
void Thread::InitRandomState() {
random_state_ = flags()->random_tags ? RandomSeed() : unique_id_;
random_state_inited_ = true;
// Push a random number of zeros onto the ring buffer so that the first stack
// tag base will be random.
for (tag_t i = 0, e = GenerateRandomTag(); i != e; ++i)
stack_allocations_->push(0);
}
void Thread::Init(uptr stack_buffer_start, uptr stack_buffer_size,
const InitState *state) {
CHECK_EQ(0, unique_id_); // try to catch bad stack reuse
CHECK_EQ(0, stack_top_);
CHECK_EQ(0, stack_bottom_);
static atomic_uint64_t unique_id;
unique_id_ = atomic_fetch_add(&unique_id, 1, memory_order_relaxed);
if (auto sz = flags()->heap_history_size)
heap_allocations_ = HeapAllocationsRingBuffer::New(sz);
#if !SANITIZER_FUCHSIA
// Do not initialize the stack ring buffer just yet on Fuchsia. Threads will
// be initialized before we enter the thread itself, so we will instead call
// this later.
InitStackRingBuffer(stack_buffer_start, stack_buffer_size);
#endif
InitStackAndTls(state);
}
void Thread::InitStackRingBuffer(uptr stack_buffer_start,
uptr stack_buffer_size) {
HwasanTSDThreadInit(); // Only needed with interceptors.
uptr *ThreadLong = GetCurrentThreadLongPtr();
// The following implicitly sets (this) as the current thread.
stack_allocations_ = new (ThreadLong)
StackAllocationsRingBuffer((void *)stack_buffer_start, stack_buffer_size);
// Check that it worked.
CHECK_EQ(GetCurrentThread(), this);
// ScopedTaggingDisable needs GetCurrentThread to be set up.
ScopedTaggingDisabler disabler;
if (stack_bottom_) {
int local;
CHECK(AddrIsInStack((uptr)&local));
CHECK(MemIsApp(stack_bottom_));
CHECK(MemIsApp(stack_top_ - 1));
}
if (flags()->verbose_threads) {
if (IsMainThread()) {
Printf("sizeof(Thread): %zd sizeof(HeapRB): %zd sizeof(StackRB): %zd\n",
sizeof(Thread), heap_allocations_->SizeInBytes(),
stack_allocations_->size() * sizeof(uptr));
}
Print("Creating : ");
}
}
void Thread::ClearShadowForThreadStackAndTLS() {
if (stack_top_ != stack_bottom_)
TagMemory(stack_bottom_, stack_top_ - stack_bottom_, 0);
if (tls_begin_ != tls_end_)
TagMemory(tls_begin_, tls_end_ - tls_begin_, 0);
}
void Thread::Destroy() {
if (flags()->verbose_threads)
Print("Destroying: ");
AllocatorSwallowThreadLocalCache(allocator_cache());
ClearShadowForThreadStackAndTLS();
if (heap_allocations_)
heap_allocations_->Delete();
DTLS_Destroy();
// Unregister this as the current thread.
// Instrumented code can not run on this thread from this point onwards, but
// malloc/free can still be served. Glibc may call free() very late, after all
// TSD destructors are done.
CHECK_EQ(GetCurrentThread(), this);
*GetCurrentThreadLongPtr() = 0;
}
void Thread::Print(const char *Prefix) {
Printf("%sT%zd %p stack: [%p,%p) sz: %zd tls: [%p,%p)\n", Prefix, unique_id_,
(void *)this, stack_bottom(), stack_top(),
stack_top() - stack_bottom(), tls_begin(), tls_end());
}
static u32 xorshift(u32 state) {
state ^= state << 13;
state ^= state >> 17;
state ^= state << 5;
return state;
}
// Generate a (pseudo-)random non-zero tag.
tag_t Thread::GenerateRandomTag(uptr num_bits) {
DCHECK_GT(num_bits, 0);
if (tagging_disabled_)
return 0;
tag_t tag;
const uptr tag_mask = (1ULL << num_bits) - 1;
do {
if (flags()->random_tags) {
if (!random_buffer_) {
EnsureRandomStateInited();
random_buffer_ = random_state_ = xorshift(random_state_);
}
CHECK(random_buffer_);
tag = random_buffer_ & tag_mask;
random_buffer_ >>= num_bits;
} else {
EnsureRandomStateInited();
random_state_ += 1;
tag = random_state_ & tag_mask;
}
} while (!tag);
return tag;
}
} // namespace __hwasan
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