we have a main program that calculate the exponentiation, whose result is the return value of int_pow. then we find the position of that function, and replace it with another function fake in machine code.

1. main program

   make 
   ./main 9 5
   

   and the program tells us that '9 to the 5 is 59049'.

2. inject program and fake machine code

   make inject
   make fake.raw
   

   fake is a very easy implementaion of addition operation.

3. copy main and hack it

   make hack
   ./hack 9 5
   

   and this time, the program tells us that '9 to the 5 is 14', which means our hack succeeds.