overflow-in-qsort.cpp
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// RUN: %clangxx_asan -O2 %s -o %t
// RUN: %env_asan_opts=fast_unwind_on_fatal=1 not %run %t 2>&1 | FileCheck %s --check-prefix=CHECK-FAST
// RUN: %env_asan_opts=fast_unwind_on_fatal=0 not %run %t 2>&1 | FileCheck %s --check-prefix=CHECK-SLOW
// Test how well we unwind in presence of qsort in the stack
// (i.e. if we can unwind through a function compiled w/o frame pointers).
// https://code.google.com/p/address-sanitizer/issues/detail?id=137
// Fast unwinder is only available on x86_64 and i386.
// REQUIRES: x86-target-arch
#include <stdlib.h>
#include <stdio.h>
int global_array[10];
volatile int one = 1;
extern "C" {
int QsortCallback(const void *a, const void *b) {
char *x = (char*)a;
char *y = (char*)b;
printf("Calling QsortCallback\n");
global_array[one * 10] = 0; // BOOM
return (int)*x - (int)*y;
}
__attribute__((noinline))
void MyQsort(char *a, size_t size) {
printf("Calling qsort\n");
qsort(a, size, sizeof(char), QsortCallback);
printf("Done\n"); // Avoid tail call.
}
} // extern "C"
int main() {
char a[2] = {1, 2};
MyQsort(a, 2);
}
// Fast unwind may not unwind through qsort.
// CHECK-FAST: ERROR: AddressSanitizer: global-buffer-overflow
// CHECK-FAST: #0{{.*}} in QsortCallback
// CHECK-FAST: is located 0 bytes to the right of global variable 'global_array
// CHECK-SLOW: ERROR: AddressSanitizer: global-buffer-overflow
// CHECK-SLOW: #0{{.*}} in QsortCallback
// CHECK-SLOW: #{{.*}} in MyQsort
// CHECK-SLOW: #{{.*}} in main
// CHECK-SLOW: is located 0 bytes to the right of global variable 'global_array