堆溢出之unlink

/*
Heap overflow vulnerable program. 
 */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int main( int argc, char * argv[] )
{
        char * first, * second;

/*[1]*/ first = malloc( 666 );
/*[2]*/ second = malloc( 12 );
        if(argc!=1)
/*[3]*/         strcpy( first, argv[1] );
/*[4]*/ free( first );
/*[5]*/ free( second );
        printf("this is morty\n");
/*[6]*/ return( 0 );
}