My first shellcode

sc.c

#include <stdio.h>
#include <stdlib.h>

/**
 *
 * ba 0b 00 00 00    ; mov ?, 0b (write ?)
 * be 01 00 00 00    ; mov ?,1 (stdout)
 * bf cb 06 40 00    ; mov edi, 0x00 40 06 cb (char * helloworld)
 * e8 bb fe ff ff    ; call fwrite
 * 5d
 * c3
 *
 * - fwrite position is not known
 * - char * helloworld position is not known either :(
 *
 */



char * sc = "\xba\x0b\x00\x00\x00\xbe\x01\x00\x00\x00\xbf\xcb\x06\x50\x00\xe8\xbb\xfe\xff\xff\x5d\xc3";


char * helloworld = "helloworld\n";

int main(void) {

  char * blah = NULL;
  blah =  0x4006cb;
  fprintf(stdout, "0x%x\n", helloworld);
  fprintf(stdout, "%s", blah);
  void * (* ret)() = (void * (*)()) sc;
  ret();
  return 0;
}