Known limitation or intra-object-overflow not working?

[Stefan_Pusl]

Hello,

normally buffer overflows are detected by address sanitizer. Then I recognized, that this is not the case, if the array is located inside a structure. Thus I created a small example (test.c):

struct xxx {

int a;

int buffer\[10\];

int b;

};

int main(void) {

struct xxx var;

int buffer\[10\];

int count;

for \(count = 0; count <=10; count\+\+\) \{

   var\.buffer\[count\] = count;

   buffer\[count\] = count;

\}

return 0;

}

The command I used is: clang -g -fsanitize=address -fsanitize-address-field-padding=2 test.c

The clang version I used is: clang version 5.0.0

When I run the executable, I get a stack-buffer-overflow. But the buffer-overflow of the array inside the structure, which happens before the stack-buffer overflow, is not detected by address sanitizer.

My question is now: Is this a known limitation of the address sanitizer or is the intra-object-overflow not working correct?

Thanks,

Stefan