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

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The test currently checks that 1-byte is allocated when malloc(0) is
called, by dereferencing the pointer.
https://github.com/llvm/llvm-project/pull/155943 changed ASan to
consider the dereference to be a heap buffer overflow. This patch
changes the test to check the allocated size is still 1-byte, but not
dereference the pointer.

This aims to fix the breakage reported in
https://github.com/llvm/llvm-project/pull/155943#issuecomment-3239543505

It also enables the test for 64-bit Windows.
This commit is contained in:
Thurston Dang 2025-08-30 22:43:51 +00:00 committed by GitHub
parent 2824b3c00e
commit 6dfd8d0ab4
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1 changed files with 7 additions and 2 deletions
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9
compiler-rt/test/asan/TestCases/Windows/heaprealloc_alloc_zero.cpp
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@ -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);