118 lines
3.6 KiB
C++
118 lines
3.6 KiB
C++
//===-- asan_fake_stack.h ---------------------------------------*- C++ -*-===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file is a part of AddressSanitizer, an address sanity checker.
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//
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// ASan-private header for asan_fake_stack.cc
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//===----------------------------------------------------------------------===//
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#ifndef ASAN_FAKE_STACK_H
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#define ASAN_FAKE_STACK_H
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namespace __asan {
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// Fake stack frame contains local variables of one function.
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struct FakeFrame {
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uptr magic; // Modified by the instrumented code.
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uptr descr; // Modified by the instrumented code.
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uptr pc; // Modified by the instrumented code.
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u64 real_stack : 48;
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u64 size_minus_one : 16;
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// End of the first 32 bytes.
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// The rest should not be used when the frame is active.
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FakeFrame *next;
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};
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struct FakeFrameFifo {
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public:
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void FifoPush(FakeFrame *node);
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FakeFrame *FifoPop();
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private:
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FakeFrame *first_, *last_;
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};
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template<uptr kMaxNumberOfFrames>
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class FakeFrameLifo {
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public:
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explicit FakeFrameLifo(LinkerInitialized) {}
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FakeFrameLifo() : n_frames_(0) {}
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void LifoPush(FakeFrame *node) {
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CHECK_LT(n_frames_, kMaxNumberOfFrames);
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frames_[n_frames_++] = node;
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}
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void LifoPop() {
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CHECK(n_frames_);
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n_frames_--;
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}
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FakeFrame *top() {
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if (n_frames_ == 0)
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return 0;
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return frames_[n_frames_ - 1];
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}
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private:
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uptr n_frames_;
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FakeFrame *frames_[kMaxNumberOfFrames];
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};
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// For each thread we create a fake stack and place stack objects on this fake
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// stack instead of the real stack. The fake stack is not really a stack but
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// a fast malloc-like allocator so that when a function exits the fake stack
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// is not poped but remains there for quite some time until gets used again.
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// So, we poison the objects on the fake stack when function returns.
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// It helps us find use-after-return bugs.
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// We can not rely on __asan_stack_free being called on every function exit,
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// so we maintain a lifo list of all current fake frames and update it on every
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// call to __asan_stack_malloc.
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class FakeStack {
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public:
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FakeStack();
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explicit FakeStack(LinkerInitialized x) : call_stack_(x) {}
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void Init(uptr stack_size);
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void StopUsingFakeStack() { alive_ = false; }
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void Cleanup();
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uptr AllocateStack(uptr size, uptr real_stack);
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static void OnFree(uptr ptr, uptr size, uptr real_stack);
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// Return the bottom of the maped region.
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uptr AddrIsInFakeStack(uptr addr);
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bool StackSize() { return stack_size_; }
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private:
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static const uptr kMinStackFrameSizeLog = 9; // Min frame is 512B.
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static const uptr kMaxStackFrameSizeLog = 16; // Max stack frame is 64K.
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static const uptr kMaxStackMallocSize = 1 << kMaxStackFrameSizeLog;
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static const uptr kNumberOfSizeClasses =
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kMaxStackFrameSizeLog - kMinStackFrameSizeLog + 1;
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static const uptr kMaxRecursionDepth = 1023;
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bool AddrIsInSizeClass(uptr addr, uptr size_class);
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// Each size class should be large enough to hold all frames.
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uptr ClassMmapSize(uptr size_class);
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uptr ClassSize(uptr size_class) {
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return 1UL << (size_class + kMinStackFrameSizeLog);
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}
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void DeallocateFrame(FakeFrame *fake_frame);
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uptr ComputeSizeClass(uptr alloc_size);
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void AllocateOneSizeClass(uptr size_class);
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uptr stack_size_;
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bool alive_;
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uptr allocated_size_classes_[kNumberOfSizeClasses];
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FakeFrameFifo size_classes_[kNumberOfSizeClasses];
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FakeFrameLifo<kMaxRecursionDepth> call_stack_;
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};
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} // namespace __asan
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#endif // ASAN_FAKE_STACK_H
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