diff libsanitizer/asan/asan_malloc_win.cpp @ 145:1830386684a0

gcc-9.2.0
author anatofuz
date Thu, 13 Feb 2020 11:34:05 +0900
parents
children
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--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/libsanitizer/asan/asan_malloc_win.cpp	Thu Feb 13 11:34:05 2020 +0900
@@ -0,0 +1,551 @@
+//===-- asan_malloc_win.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.
+//
+// Windows-specific malloc interception.
+//===----------------------------------------------------------------------===//
+
+#include "sanitizer_common/sanitizer_allocator_interface.h"
+#include "sanitizer_common/sanitizer_platform.h"
+#if SANITIZER_WINDOWS
+#include "asan_allocator.h"
+#include "asan_interceptors.h"
+#include "asan_internal.h"
+#include "asan_stack.h"
+#include "interception/interception.h"
+#include <stddef.h>
+
+// Intentionally not including windows.h here, to avoid the risk of
+// pulling in conflicting declarations of these functions. (With mingw-w64,
+// there's a risk of windows.h pulling in stdint.h.)
+typedef int BOOL;
+typedef void *HANDLE;
+typedef const void *LPCVOID;
+typedef void *LPVOID;
+
+typedef unsigned long DWORD;
+constexpr unsigned long HEAP_ZERO_MEMORY = 0x00000008;
+constexpr unsigned long HEAP_REALLOC_IN_PLACE_ONLY = 0x00000010;
+constexpr unsigned long HEAP_ALLOCATE_SUPPORTED_FLAGS = (HEAP_ZERO_MEMORY);
+constexpr unsigned long HEAP_ALLOCATE_UNSUPPORTED_FLAGS =
+    (~HEAP_ALLOCATE_SUPPORTED_FLAGS);
+constexpr unsigned long HEAP_FREE_UNSUPPORTED_FLAGS =
+    (~HEAP_ALLOCATE_SUPPORTED_FLAGS);
+constexpr unsigned long HEAP_REALLOC_UNSUPPORTED_FLAGS =
+    (~HEAP_ALLOCATE_SUPPORTED_FLAGS);
+
+
+extern "C" {
+LPVOID WINAPI HeapAlloc(HANDLE hHeap, DWORD dwFlags, size_t dwBytes);
+LPVOID WINAPI HeapReAlloc(HANDLE hHeap, DWORD dwFlags, LPVOID lpMem,
+                         size_t dwBytes);
+BOOL WINAPI HeapFree(HANDLE hHeap, DWORD dwFlags, LPVOID lpMem);
+size_t WINAPI HeapSize(HANDLE hHeap, DWORD dwFlags, LPCVOID lpMem);
+
+BOOL WINAPI HeapValidate(HANDLE hHeap, DWORD dwFlags, LPCVOID lpMem);
+}
+
+using namespace __asan;
+
+// MT: Simply defining functions with the same signature in *.obj
+// files overrides the standard functions in the CRT.
+// MD: Memory allocation functions are defined in the CRT .dll,
+// so we have to intercept them before they are called for the first time.
+
+#if ASAN_DYNAMIC
+# define ALLOCATION_FUNCTION_ATTRIBUTE
+#else
+# define ALLOCATION_FUNCTION_ATTRIBUTE SANITIZER_INTERFACE_ATTRIBUTE
+#endif
+
+extern "C" {
+ALLOCATION_FUNCTION_ATTRIBUTE
+size_t _msize(void *ptr) {
+  GET_CURRENT_PC_BP_SP;
+  (void)sp;
+  return asan_malloc_usable_size(ptr, pc, bp);
+}
+
+ALLOCATION_FUNCTION_ATTRIBUTE
+size_t _msize_base(void *ptr) {
+  return _msize(ptr);
+}
+
+ALLOCATION_FUNCTION_ATTRIBUTE
+void free(void *ptr) {
+  GET_STACK_TRACE_FREE;
+  return asan_free(ptr, &stack, FROM_MALLOC);
+}
+
+ALLOCATION_FUNCTION_ATTRIBUTE
+void _free_dbg(void *ptr, int) {
+  free(ptr);
+}
+
+ALLOCATION_FUNCTION_ATTRIBUTE
+void _free_base(void *ptr) {
+  free(ptr);
+}
+
+ALLOCATION_FUNCTION_ATTRIBUTE
+void *malloc(size_t size) {
+  GET_STACK_TRACE_MALLOC;
+  return asan_malloc(size, &stack);
+}
+
+ALLOCATION_FUNCTION_ATTRIBUTE
+void *_malloc_base(size_t size) {
+  return malloc(size);
+}
+
+ALLOCATION_FUNCTION_ATTRIBUTE
+void *_malloc_dbg(size_t size, int, const char *, int) {
+  return malloc(size);
+}
+
+ALLOCATION_FUNCTION_ATTRIBUTE
+void *calloc(size_t nmemb, size_t size) {
+  GET_STACK_TRACE_MALLOC;
+  return asan_calloc(nmemb, size, &stack);
+}
+
+ALLOCATION_FUNCTION_ATTRIBUTE
+void *_calloc_base(size_t nmemb, size_t size) {
+  return calloc(nmemb, size);
+}
+
+ALLOCATION_FUNCTION_ATTRIBUTE
+void *_calloc_dbg(size_t nmemb, size_t size, int, const char *, int) {
+  return calloc(nmemb, size);
+}
+
+ALLOCATION_FUNCTION_ATTRIBUTE
+void *_calloc_impl(size_t nmemb, size_t size, int *errno_tmp) {
+  return calloc(nmemb, size);
+}
+
+ALLOCATION_FUNCTION_ATTRIBUTE
+void *realloc(void *ptr, size_t size) {
+  GET_STACK_TRACE_MALLOC;
+  return asan_realloc(ptr, size, &stack);
+}
+
+ALLOCATION_FUNCTION_ATTRIBUTE
+void *_realloc_dbg(void *ptr, size_t size, int) {
+  UNREACHABLE("_realloc_dbg should not exist!");
+  return 0;
+}
+
+ALLOCATION_FUNCTION_ATTRIBUTE
+void *_realloc_base(void *ptr, size_t size) {
+  return realloc(ptr, size);
+}
+
+ALLOCATION_FUNCTION_ATTRIBUTE
+void *_recalloc(void *p, size_t n, size_t elem_size) {
+  if (!p)
+    return calloc(n, elem_size);
+  const size_t size = n * elem_size;
+  if (elem_size != 0 && size / elem_size != n)
+    return 0;
+
+  size_t old_size = _msize(p);
+  void *new_alloc = malloc(size);
+  if (new_alloc) {
+    REAL(memcpy)(new_alloc, p, Min<size_t>(size, old_size));
+    if (old_size < size)
+      REAL(memset)(((u8 *)new_alloc) + old_size, 0, size - old_size);
+    free(p);
+  }
+  return new_alloc;
+}
+
+ALLOCATION_FUNCTION_ATTRIBUTE
+void *_recalloc_base(void *p, size_t n, size_t elem_size) {
+  return _recalloc(p, n, elem_size);
+}
+
+ALLOCATION_FUNCTION_ATTRIBUTE
+void *_expand(void *memblock, size_t size) {
+  // _expand is used in realloc-like functions to resize the buffer if possible.
+  // We don't want memory to stand still while resizing buffers, so return 0.
+  return 0;
+}
+
+ALLOCATION_FUNCTION_ATTRIBUTE
+void *_expand_dbg(void *memblock, size_t size) {
+  return _expand(memblock, size);
+}
+
+// TODO(timurrrr): Might want to add support for _aligned_* allocation
+// functions to detect a bit more bugs.  Those functions seem to wrap malloc().
+
+int _CrtDbgReport(int, const char*, int,
+                  const char*, const char*, ...) {
+  ShowStatsAndAbort();
+}
+
+int _CrtDbgReportW(int reportType, const wchar_t*, int,
+                   const wchar_t*, const wchar_t*, ...) {
+  ShowStatsAndAbort();
+}
+
+int _CrtSetReportMode(int, int) {
+  return 0;
+}
+}  // extern "C"
+
+#define OWNED_BY_RTL(heap, memory) \
+  (!__sanitizer_get_ownership(memory) && HeapValidate(heap, 0, memory))
+
+INTERCEPTOR_WINAPI(size_t, HeapSize, HANDLE hHeap, DWORD dwFlags,
+                   LPCVOID lpMem) {
+  // If the RTL allocators are hooked we need to check whether the ASAN
+  // allocator owns the pointer we're about to use. Allocations occur before
+  // interception takes place, so if it is not owned by the RTL heap we can
+  // pass it to the ASAN heap for inspection.
+  if (flags()->windows_hook_rtl_allocators) {
+    if (!asan_inited || OWNED_BY_RTL(hHeap, lpMem))
+      return REAL(HeapSize)(hHeap, dwFlags, lpMem);
+  } else {
+    CHECK(dwFlags == 0 && "unsupported heap flags");
+  }
+  GET_CURRENT_PC_BP_SP;
+  (void)sp;
+  return asan_malloc_usable_size(lpMem, pc, bp);
+}
+
+INTERCEPTOR_WINAPI(LPVOID, HeapAlloc, HANDLE hHeap, DWORD dwFlags,
+                   size_t dwBytes) {
+  // If the ASAN runtime is not initialized, or we encounter an unsupported
+  // flag, fall back to the original allocator.
+  if (flags()->windows_hook_rtl_allocators) {
+    if (UNLIKELY(!asan_inited ||
+                 (dwFlags & HEAP_ALLOCATE_UNSUPPORTED_FLAGS) != 0)) {
+      return REAL(HeapAlloc)(hHeap, dwFlags, dwBytes);
+    }
+  } else {
+    // In the case that we don't hook the rtl allocators,
+    // this becomes an assert since there is no failover to the original
+    // allocator.
+    CHECK((HEAP_ALLOCATE_UNSUPPORTED_FLAGS & dwFlags) != 0 &&
+          "unsupported flags");
+  }
+  GET_STACK_TRACE_MALLOC;
+  void *p = asan_malloc(dwBytes, &stack);
+  // Reading MSDN suggests that the *entire* usable allocation is zeroed out.
+  // Otherwise it is difficult to HeapReAlloc with HEAP_ZERO_MEMORY.
+  // https://blogs.msdn.microsoft.com/oldnewthing/20120316-00/?p=8083
+  if (p && (dwFlags & HEAP_ZERO_MEMORY)) {
+    GET_CURRENT_PC_BP_SP;
+    (void)sp;
+    auto usable_size = asan_malloc_usable_size(p, pc, bp);
+    internal_memset(p, 0, usable_size);
+  }
+  return p;
+}
+
+INTERCEPTOR_WINAPI(BOOL, HeapFree, HANDLE hHeap, DWORD dwFlags, LPVOID lpMem) {
+  // Heap allocations happen before this function is hooked, so we must fall
+  // back to the original function if the pointer is not from the ASAN heap,
+  // or unsupported flags are provided.
+  if (flags()->windows_hook_rtl_allocators) {
+    if (OWNED_BY_RTL(hHeap, lpMem))
+      return REAL(HeapFree)(hHeap, dwFlags, lpMem);
+  } else {
+    CHECK((HEAP_FREE_UNSUPPORTED_FLAGS & dwFlags) != 0 && "unsupported flags");
+  }
+  GET_STACK_TRACE_FREE;
+  asan_free(lpMem, &stack, FROM_MALLOC);
+  return true;
+}
+
+namespace __asan {
+using AllocFunction = LPVOID(WINAPI *)(HANDLE, DWORD, size_t);
+using ReAllocFunction = LPVOID(WINAPI *)(HANDLE, DWORD, LPVOID, size_t);
+using SizeFunction = size_t(WINAPI *)(HANDLE, DWORD, LPVOID);
+using FreeFunction = BOOL(WINAPI *)(HANDLE, DWORD, LPVOID);
+
+void *SharedReAlloc(ReAllocFunction reallocFunc, SizeFunction heapSizeFunc,
+                    FreeFunction freeFunc, AllocFunction allocFunc,
+                    HANDLE hHeap, DWORD dwFlags, LPVOID lpMem, size_t dwBytes) {
+  CHECK(reallocFunc && heapSizeFunc && freeFunc && allocFunc);
+  GET_STACK_TRACE_MALLOC;
+  GET_CURRENT_PC_BP_SP;
+  (void)sp;
+  if (flags()->windows_hook_rtl_allocators) {
+    enum AllocationOwnership { NEITHER = 0, ASAN = 1, RTL = 2 };
+    AllocationOwnership ownershipState;
+    bool owned_rtlalloc = false;
+    bool owned_asan = __sanitizer_get_ownership(lpMem);
+
+    if (!owned_asan)
+      owned_rtlalloc = HeapValidate(hHeap, 0, lpMem);
+
+    if (owned_asan && !owned_rtlalloc)
+      ownershipState = ASAN;
+    else if (!owned_asan && owned_rtlalloc)
+      ownershipState = RTL;
+    else if (!owned_asan && !owned_rtlalloc)
+      ownershipState = NEITHER;
+
+    // If this heap block which was allocated before the ASAN
+    // runtime came up, use the real HeapFree function.
+    if (UNLIKELY(!asan_inited)) {
+      return reallocFunc(hHeap, dwFlags, lpMem, dwBytes);
+    }
+    bool only_asan_supported_flags =
+        (HEAP_REALLOC_UNSUPPORTED_FLAGS & dwFlags) == 0;
+
+    if (ownershipState == RTL ||
+        (ownershipState == NEITHER && !only_asan_supported_flags)) {
+      if (only_asan_supported_flags) {
+        // if this is a conversion to ASAN upported flags, transfer this
+        // allocation to the ASAN allocator
+        void *replacement_alloc;
+        if (dwFlags & HEAP_ZERO_MEMORY)
+          replacement_alloc = asan_calloc(1, dwBytes, &stack);
+        else
+          replacement_alloc = asan_malloc(dwBytes, &stack);
+        if (replacement_alloc) {
+          size_t old_size = heapSizeFunc(hHeap, dwFlags, lpMem);
+          if (old_size == ((size_t)0) - 1) {
+            asan_free(replacement_alloc, &stack, FROM_MALLOC);
+            return nullptr;
+          }
+          REAL(memcpy)(replacement_alloc, lpMem, old_size);
+          freeFunc(hHeap, dwFlags, lpMem);
+        }
+        return replacement_alloc;
+      } else {
+        // owned by rtl or neither with unsupported ASAN flags,
+        // just pass back to original allocator
+        CHECK(ownershipState == RTL || ownershipState == NEITHER);
+        CHECK(!only_asan_supported_flags);
+        return reallocFunc(hHeap, dwFlags, lpMem, dwBytes);
+      }
+    }
+
+    if (ownershipState == ASAN && !only_asan_supported_flags) {
+      // Conversion to unsupported flags allocation,
+      // transfer this allocation back to the original allocator.
+      void *replacement_alloc = allocFunc(hHeap, dwFlags, dwBytes);
+      size_t old_usable_size = 0;
+      if (replacement_alloc) {
+        old_usable_size = asan_malloc_usable_size(lpMem, pc, bp);
+        REAL(memcpy)(replacement_alloc, lpMem,
+                     Min<size_t>(dwBytes, old_usable_size));
+        asan_free(lpMem, &stack, FROM_MALLOC);
+      }
+      return replacement_alloc;
+    }
+
+    CHECK((ownershipState == ASAN || ownershipState == NEITHER) &&
+          only_asan_supported_flags);
+    // At this point we should either be ASAN owned with ASAN supported flags
+    // or we owned by neither and have supported flags.
+    // Pass through even when it's neither since this could be a null realloc or
+    // UAF that ASAN needs to catch.
+  } else {
+    CHECK((HEAP_REALLOC_UNSUPPORTED_FLAGS & dwFlags) != 0 &&
+          "unsupported flags");
+  }
+  // asan_realloc will never reallocate in place, so for now this flag is
+  // unsupported until we figure out a way to fake this.
+  if (dwFlags & HEAP_REALLOC_IN_PLACE_ONLY)
+    return nullptr;
+
+  // HeapReAlloc and HeapAlloc both happily accept 0 sized allocations.
+  // passing a 0 size into asan_realloc will free the allocation.
+  // To avoid this and keep behavior consistent, fudge the size if 0.
+  // (asan_malloc already does this)
+  if (dwBytes == 0)
+    dwBytes = 1;
+
+  size_t old_size;
+  if (dwFlags & HEAP_ZERO_MEMORY)
+    old_size = asan_malloc_usable_size(lpMem, pc, bp);
+
+  void *ptr = asan_realloc(lpMem, dwBytes, &stack);
+  if (ptr == nullptr)
+    return nullptr;
+
+  if (dwFlags & HEAP_ZERO_MEMORY) {
+    size_t new_size = asan_malloc_usable_size(ptr, pc, bp);
+    if (old_size < new_size)
+      REAL(memset)(((u8 *)ptr) + old_size, 0, new_size - old_size);
+  }
+
+  return ptr;
+}
+}  // namespace __asan
+
+INTERCEPTOR_WINAPI(LPVOID, HeapReAlloc, HANDLE hHeap, DWORD dwFlags,
+                   LPVOID lpMem, size_t dwBytes) {
+  return SharedReAlloc(REAL(HeapReAlloc), (SizeFunction)REAL(HeapSize),
+                       REAL(HeapFree), REAL(HeapAlloc), hHeap, dwFlags, lpMem,
+                       dwBytes);
+}
+
+// The following functions are undocumented and subject to change.
+// However, hooking them is necessary to hook Windows heap
+// allocations with detours and their definitions are unlikely to change.
+// Comments in /minkernel/ntos/rtl/heappublic.c indicate that these functions
+// are part of the heap's public interface.
+typedef unsigned long LOGICAL;
+
+// This function is documented as part of the Driver Development Kit but *not*
+// the Windows Development Kit.
+LOGICAL RtlFreeHeap(void* HeapHandle, DWORD Flags,
+                            void* BaseAddress);
+
+// This function is documented as part of the Driver Development Kit but *not*
+// the Windows Development Kit.
+void* RtlAllocateHeap(void* HeapHandle, DWORD Flags, size_t Size);
+
+// This function is completely undocumented.
+void*
+RtlReAllocateHeap(void* HeapHandle, DWORD Flags, void* BaseAddress,
+                  size_t Size);
+
+// This function is completely undocumented.
+size_t RtlSizeHeap(void* HeapHandle, DWORD Flags, void* BaseAddress);
+
+INTERCEPTOR_WINAPI(size_t, RtlSizeHeap, HANDLE HeapHandle, DWORD Flags,
+                   void* BaseAddress) {
+  if (!flags()->windows_hook_rtl_allocators ||
+      UNLIKELY(!asan_inited || OWNED_BY_RTL(HeapHandle, BaseAddress))) {
+    return REAL(RtlSizeHeap)(HeapHandle, Flags, BaseAddress);
+  }
+  GET_CURRENT_PC_BP_SP;
+  (void)sp;
+  return asan_malloc_usable_size(BaseAddress, pc, bp);
+}
+
+INTERCEPTOR_WINAPI(BOOL, RtlFreeHeap, HANDLE HeapHandle, DWORD Flags,
+                   void* BaseAddress) {
+  // Heap allocations happen before this function is hooked, so we must fall
+  // back to the original function if the pointer is not from the ASAN heap, or
+  // unsupported flags are provided.
+  if (!flags()->windows_hook_rtl_allocators ||
+      UNLIKELY((HEAP_FREE_UNSUPPORTED_FLAGS & Flags) != 0 ||
+               OWNED_BY_RTL(HeapHandle, BaseAddress))) {
+    return REAL(RtlFreeHeap)(HeapHandle, Flags, BaseAddress);
+  }
+  GET_STACK_TRACE_FREE;
+  asan_free(BaseAddress, &stack, FROM_MALLOC);
+  return true;
+}
+
+INTERCEPTOR_WINAPI(void*, RtlAllocateHeap, HANDLE HeapHandle, DWORD Flags,
+                   size_t Size) {
+  // If the ASAN runtime is not initialized, or we encounter an unsupported
+  // flag, fall back to the original allocator.
+  if (!flags()->windows_hook_rtl_allocators ||
+      UNLIKELY(!asan_inited ||
+               (Flags & HEAP_ALLOCATE_UNSUPPORTED_FLAGS) != 0)) {
+    return REAL(RtlAllocateHeap)(HeapHandle, Flags, Size);
+  }
+  GET_STACK_TRACE_MALLOC;
+  void *p;
+  // Reading MSDN suggests that the *entire* usable allocation is zeroed out.
+  // Otherwise it is difficult to HeapReAlloc with HEAP_ZERO_MEMORY.
+  // https://blogs.msdn.microsoft.com/oldnewthing/20120316-00/?p=8083
+  if (Flags & HEAP_ZERO_MEMORY) {
+    p = asan_calloc(Size, 1, &stack);
+  } else {
+    p = asan_malloc(Size, &stack);
+  }
+  return p;
+}
+
+INTERCEPTOR_WINAPI(void*, RtlReAllocateHeap, HANDLE HeapHandle, DWORD Flags,
+                   void* BaseAddress, size_t Size) {
+  // If it's actually a heap block which was allocated before the ASAN runtime
+  // came up, use the real RtlFreeHeap function.
+  if (!flags()->windows_hook_rtl_allocators)
+    return REAL(RtlReAllocateHeap)(HeapHandle, Flags, BaseAddress, Size);
+
+  return SharedReAlloc(REAL(RtlReAllocateHeap), REAL(RtlSizeHeap),
+                       REAL(RtlFreeHeap), REAL(RtlAllocateHeap), HeapHandle,
+                       Flags, BaseAddress, Size);
+}
+
+namespace __asan {
+
+static void TryToOverrideFunction(const char *fname, uptr new_func) {
+  // Failure here is not fatal. The CRT may not be present, and different CRT
+  // versions use different symbols.
+  if (!__interception::OverrideFunction(fname, new_func))
+    VPrintf(2, "Failed to override function %s\n", fname);
+}
+
+void ReplaceSystemMalloc() {
+#if defined(ASAN_DYNAMIC)
+  TryToOverrideFunction("free", (uptr)free);
+  TryToOverrideFunction("_free_base", (uptr)free);
+  TryToOverrideFunction("malloc", (uptr)malloc);
+  TryToOverrideFunction("_malloc_base", (uptr)malloc);
+  TryToOverrideFunction("_malloc_crt", (uptr)malloc);
+  TryToOverrideFunction("calloc", (uptr)calloc);
+  TryToOverrideFunction("_calloc_base", (uptr)calloc);
+  TryToOverrideFunction("_calloc_crt", (uptr)calloc);
+  TryToOverrideFunction("realloc", (uptr)realloc);
+  TryToOverrideFunction("_realloc_base", (uptr)realloc);
+  TryToOverrideFunction("_realloc_crt", (uptr)realloc);
+  TryToOverrideFunction("_recalloc", (uptr)_recalloc);
+  TryToOverrideFunction("_recalloc_base", (uptr)_recalloc);
+  TryToOverrideFunction("_recalloc_crt", (uptr)_recalloc);
+  TryToOverrideFunction("_msize", (uptr)_msize);
+  TryToOverrideFunction("_msize_base", (uptr)_msize);
+  TryToOverrideFunction("_expand", (uptr)_expand);
+  TryToOverrideFunction("_expand_base", (uptr)_expand);
+
+  if (flags()->windows_hook_rtl_allocators) {
+    INTERCEPT_FUNCTION(HeapSize);
+    INTERCEPT_FUNCTION(HeapFree);
+    INTERCEPT_FUNCTION(HeapReAlloc);
+    INTERCEPT_FUNCTION(HeapAlloc);
+
+    // Undocumented functions must be intercepted by name, not by symbol.
+    __interception::OverrideFunction("RtlSizeHeap", (uptr)WRAP(RtlSizeHeap),
+                                     (uptr *)&REAL(RtlSizeHeap));
+    __interception::OverrideFunction("RtlFreeHeap", (uptr)WRAP(RtlFreeHeap),
+                                     (uptr *)&REAL(RtlFreeHeap));
+    __interception::OverrideFunction("RtlReAllocateHeap",
+                                     (uptr)WRAP(RtlReAllocateHeap),
+                                     (uptr *)&REAL(RtlReAllocateHeap));
+    __interception::OverrideFunction("RtlAllocateHeap",
+                                     (uptr)WRAP(RtlAllocateHeap),
+                                     (uptr *)&REAL(RtlAllocateHeap));
+  } else {
+#define INTERCEPT_UCRT_FUNCTION(func)                                  \
+  if (!INTERCEPT_FUNCTION_DLLIMPORT(                                   \
+          "ucrtbase.dll", "api-ms-win-core-heap-l1-1-0.dll", func)) {  \
+    VPrintf(2, "Failed to intercept ucrtbase.dll import %s\n", #func); \
+  }
+    INTERCEPT_UCRT_FUNCTION(HeapAlloc);
+    INTERCEPT_UCRT_FUNCTION(HeapFree);
+    INTERCEPT_UCRT_FUNCTION(HeapReAlloc);
+    INTERCEPT_UCRT_FUNCTION(HeapSize);
+#undef INTERCEPT_UCRT_FUNCTION
+  }
+  // Recent versions of ucrtbase.dll appear to be built with PGO and LTCG, which
+  // enable cross-module inlining. This means our _malloc_base hook won't catch
+  // all CRT allocations. This code here patches the import table of
+  // ucrtbase.dll so that all attempts to use the lower-level win32 heap
+  // allocation API will be directed to ASan's heap. We don't currently
+  // intercept all calls to HeapAlloc. If we did, we would have to check on
+  // HeapFree whether the pointer came from ASan of from the system.
+
+#endif  // defined(ASAN_DYNAMIC)
+}
+}  // namespace __asan
+
+#endif  // _WIN32