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[asan] Rewrite Windows/heaprealloc_alloc_zero check to avoid dereference #156211

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Merged
merged 2 commits into from
Aug 30, 2025
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[asan] Rewrite Windows/heaprealloc_alloc_zero check to avoid dereference #156211

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cb5e1f2
[asan] Rewrite Windows/heaprealloc_alloc_zero check to avoid dereference
thurstond Aug 30, 2025
cc22e49
Enable test for 64-bit Windows as well
thurstond Aug 30, 2025
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9 changes: 7 additions & 2 deletions compiler-rt/test/asan/TestCases/Windows/heaprealloc_alloc_zero.cpp
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Original file line number Diff line number Diff line change
@@ -1,15 +1,20 @@
// RUN: %clang_cl_asan %Od %MT -o %t %s
// RUN: %env_asan_opts=windows_hook_rtl_allocators=true %run %t 2>&1 | FileCheck %s
// UNSUPPORTED: asan-64-bits
#include <cassert>
#include <iostream>
#include <sanitizer/allocator_interface.h>
#include <windows.h>

int main() {
void *ptr = malloc(0);
if (ptr)
std::cerr << "allocated!\n";
((char *)ptr)[0] = '\xff'; //check this 'allocate 1 instead of 0' hack hasn't changed

// Check the 'allocate 1 instead of 0' hack hasn't changed
// Note that as of b3452d90b043a398639e62b0ab01aa339cc649de, dereferencing
// the pointer will be detected as a heap-buffer-overflow.
if (__sanitizer_get_allocated_size(ptr) != 1)
return 1;

free(ptr);

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