Error: calloc-overflow

Address Sanitizer Error: calloc-overflow

The CRT function calloc creates an array in memory with elements initialized to 0. The arguments can create an internal error that leads to a NULL pointer as the return value.

Example

// example1.cpp
// calloc-overflow error
#include <stdio.h>
#include <stdlib.h>

int number = -1;
int element_size = 1000;

int main() {

    void *p = calloc(number, element_size);      // Boom!

    printf("calloc returned: %zu\n", (size_t)p);

    return 0;
}

To build and test this example, run these commands in a Visual Studio 2019 version 16.9 or later developer command prompt:

cl example1.cpp /fsanitize=address /Zi
devenv /debugexe example1.exe

Resulting error

See also

AddressSanitizer overview
AddressSanitizer known issues
AddressSanitizer build and language reference
AddressSanitizer runtime reference
AddressSanitizer shadow bytes
AddressSanitizer cloud or distributed testing
AddressSanitizer debugger integration
AddressSanitizer error examples